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Identification and characterization of mutations in housefly (Musca domestica) acetylcholinesterase involved in insecticide resistance
DEFF Research Database (Denmark)
Walsh, Sinead B.; Dolden, Tracey A.; Moores, Graham D.
Acetylcholinesterase (AChE) insensitive to organophosphate and carbamate insecticides has been identified as a major resistance mechanism in numerous arthropod species. However, the associated genetic changes have been reported in the AChE genes from only three insect species; their role in confe...... of the AChE protein from Torpedo californica and D. melanogaster....
Resistance to Insecticides in Insects
In recent years, the frequent usage of insecticides in struggle aganist insects, has caused development of resistance to those chemicals in insects. The increase in dosage of insecticide used due to development of resistance in insects, causes important problems in terms of environment and human health. This study includes topics such as insecticides which are used frequently in insect struggle, insecticide resistant types, genetic changes posing resistance, enzymes of resistance and resistan...
Energetic cost of insecticide resistance in Culex pipiens mosquitoes.
Rivero, A; Magaud, A; Nicot, A; Vézilier, J
The extensive use of insecticides to control vector populations has lead to the widespread development of different mechanisms of insecticide resistance. Mutations that confer insecticide resistance are often associated to fitness costs that prevent them from spreading to fixation. In vectors, such fitness costs include reductions in preimaginal survival, adult size, longevity, and fecundity. The most commonly invoked explanation for the nature of such pleiotropic effects of insecticide resistance is the existence of resource-based trade-offs. According to this hypothesis, insecticide resistance would deplete the energetic stores of vectors, reducing the energy available for other biological functions and generating trade-offs between insecticide resistance and key life history traits. Here we test this hypothesis by quantifying the energetic resources (lipids, glycogen, and glucose) of larvae and adult females of the mosquito Culex pipiens L. resistant to insecticides through two different mechanisms: esterase overproduction and acetylcholinesterase modification. We find that, as expected from trade-off theory, insecticide resistant mosquitoes through the overproduction of esterases contain on average 30% less energetic reserves than their susceptible counterparts. Acetylcholinesterase-modified mosquitoes, however, also showed a significant reduction in energetic resources (20% less). We suggest that, in acetylcholinesterase-modified mosquitoes, resource depletion may not be the result of resource-based trade-offs but a consequence of the hyperactivation of the nervous system. We argue that these results not only provide a mechanistic explanation for the negative pleiotropic effects of insecticide resistance on mosquito life history traits but also can have a direct effect on the development of parasites that depend on the vector's energetic reserves to fulfil their own metabolic needs.
Insecticide resistance in Bemisia tabaci from Cyprus
Institute of Scientific and Technical Information of China (English)
Vassilis Vassiliou; Maria Emmanouilidou; Andreas Perrakis; Evangelia Morou; John Vontas; Anastasia Tsagkarakou; Emmanouil Roditakis
A comprehensive study on the Bemisia tabaci(biotype B)resistance to neonicotinoid insecticides imidacloprid,acetamiprid and thiamethoxam,and pyrethroid bifenthrin was conducted in Cyprus.The resistance level to eight field-collected B.tabaci populations was investigated.The activities of enzymes involved in metabolic detoxification and the frequencies of pyrethroid and organophosphates target site resistance mutations were determined.Moderate to high levels of resistance were detected for imidacloprid(resistance factor[RF]77-392)and thiamethoxam(RF 50-164)while low resistance levels were observed for acetamiprid(RF 7-12).Uniform responses by the Cypriot whiteflies could be observed against all neonicotinoid insecticides.No cross-resistance between the neonicotinoids was detected as well as no association with the activity of the P450 microsomal oxidases.Only imidacloprid resistance correlated with carboxylesterase activity.Low to extremely high resistance was observed for insecticide bifenthrin(RF 49-1 243)which was associated with the frequency of the resistant allele in the sodium channel gene but not with the activity of the detoxification enzymes.Finally,the F331W mutation in the acetylcholinesterase enzyme ace1 gene was fixed in all B.tabaci populations from Cyprus.
Site-directed mutagenesis of an acetylcholinesterase gene from the yellow fever mosquito Aedes aegypti confers insecticide insensitivity.
Vaughan, A; Rocheleau, T; ffrench-Constant, R
Insecticide resistance is a serious problem facing the effective control of insect vectors of disease. Insensitive acetylcholinesterase (AChE) confers resistance to organophosphorus (OP) and carbamate insecticides and is a widespread resistance mechanism in vector mosquitoes. Although the point mutations that underlie AChE insensitivity have been described from Drosophila, the Colorado potato beetle, and house flies, no resistance associated mutations have been documented from mosquitoes to date. We are therefore using a cloned acetylcholinesterase gene from the yellow fever mosquito Aedes aegypti as a model in which to perform site directed mutagenesis in order to understand the effects of potential resistance associated mutations. The same resistance associated amino-acid replacements as found in other insects also confer OP and carbamate resistance to the mosquito enzyme. Here we describe the levels of resistance conferred by different combinations of these mutations and the effects of these mutations on the kinetics of the AChE enzyme. Over-expression of these constructs in baculovirus will facilitate purification of each of the mutant enzymes and a more detailed analysis of their associated inhibition kinetics.
[Determination of insecticide-resistance and resistance mechanisms of Blattella germanica (Dictyoptera: Blattellidae)].
Díaz, Pantoja Cristina; Alvarez Gavilán, Yudelmis; de Armas Rodríguez, Yaxsier; Bisset Lazcano, Juan A
In this paper, the level of resistance to four insecticides of 3 Blatella germanica strains collected from various places in the City of Havana province was evaluated. These strains were resistant to two pyrethroids (cypermethrin and lambda-cyalothrine) and to organophosphorate malathion but susceptible to carbamate propoxur. The values of alpha and beta esterases, acetylcholinesterase and gluthatione-S-transferase were estimated in three strains involved in the study. The results of the study showed high esterase activity in all the strains, mainly beta esterases and two of the three strains presented with high gluthation-S-transferase enzyme. No changes in acetylcholinesterase were demonstrated in relation to the reference strain. The association of levels of resistance to insecticides, the possible resistance mechanisms in each strain and the results of the enzymatic activity were also analyzed.
Multiple insecticide resistance: an impediment to insecticide-based malaria vector control program.
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Delenasaw Yewhalaw
Full Text Available BACKGROUND: Indoor Residual Spraying (IRS, insecticide-treated nets (ITNs and long-lasting insecticidal nets (LLINs are key components in malaria prevention and control strategy. However, the development of resistance by mosquitoes to insecticides recommended for IRS and/or ITNs/LLINs would affect insecticide-based malaria vector control. We assessed the susceptibility levels of Anopheles arabiensis to insecticides used in malaria control, characterized basic mechanisms underlying resistance, and evaluated the role of public health use of insecticides in resistance selection. METHODOLOGY/PRINCIPAL FINDINGS: Susceptibility status of An. arabiensis was assessed using WHO bioassay tests to DDT, permethrin, deltamethrin, malathion and propoxur in Ethiopia from August to September 2009. Mosquito specimens were screened for knockdown resistance (kdr and insensitive acetylcholinesterase (ace-1(R mutations using AS-PCR and PCR-RFLP, respectively. DDT residues level in soil from human dwellings and the surrounding environment were determined by Gas Chromatography with Electron Capture Detector. An. arabiensis was resistant to DDT, permethrin, deltamethrin and malathion, but susceptible to propoxur. The West African kdr allele was found in 280 specimens out of 284 with a frequency ranged from 95% to 100%. Ace-1(R mutation was not detected in all specimens scored for the allele. Moreover, DDT residues were found in soil samples from human dwellings but not in the surrounding environment. CONCLUSION: The observed multiple-resistance coupled with the occurrence of high kdr frequency in populations of An. arabiensis could profoundly affect the malaria vector control programme in Ethiopia. This needs an urgent call for implementing rational resistance management strategies and integrated vector control intervention.
Novel AChE inhibitors for sustainable insecticide resistance management.
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Haoues Alout
Full Text Available Resistance to insecticides has become a critical issue in pest management and it is particularly chronic in the control of human disease vectors. The gravity of this situation is being exacerbated since there has not been a new insecticide class produced for over twenty years. Reasoned strategies have been developed to limit resistance spread but have proven difficult to implement in the field. Here we propose a new conceptual strategy based on inhibitors that preferentially target mosquitoes already resistant to a currently used insecticide. Application of such inhibitors in rotation with the insecticide against which resistance has been selected initially is expected to restore vector control efficacy and reduce the odds of neo-resistance. We validated this strategy by screening for inhibitors of the G119S mutated acetylcholinesterase-1 (AChE1, which mediates insensitivity to the widely used organophosphates (OP and carbamates (CX insecticides. PyrimidineTrione Furan-substituted (PTF compounds came out as best hits, acting biochemically as reversible and competitive inhibitors of mosquito AChE1 and preferentially inhibiting the mutated form, insensitive to OP and CX. PTF application in bioassays preferentially killed OP-resistant Culex pipiens and Anopheles gambiae larvae as a consequence of AChE1 inhibition. Modeling the evolution of frequencies of wild type and OP-insensitive AChE1 alleles in PTF-treated populations using the selectivity parameters estimated from bioassays predicts a rapid rise in the wild type allele frequency. This study identifies the first compound class that preferentially targets OP-resistant mosquitoes, thus restoring OP-susceptibility, which validates a new prospect of sustainable insecticide resistance management.
Insecticide Resistance Management
thuringiensis var. membranes israeknsis A2 Bacillus sphaencus Inhibitocs of chitin biosynthesis type 0 15 Benzaylureas Diflubenzuron, triflnmuron...resistance can detoxify or destroy the pesticide toxins at a faster rate, break down the toxins inside the body, and/or prevent the pesticide from entering...hocmone analogues MethOJre!le, hydorpene Juvenile hormone mimics 7 c Pyri proxyfen Pyriproxyfen Microbial disrupters of insect midgut 11 AI Bacillus
Immobilization of acetylcholinesterase on one-dimensional gold nanoparticles for detection of organophosphorous insecticides
Institute of Scientific and Technical Information of China (English)
This paper reports a simple method for immobilization of acetylcholinesterase (AChE) on one-dimensional (1D) gold (Au) nanoparticles for detection of organophosphorous (OP) insecticides. 1D Au nanoparticles were prepared by electrodeposition in the pores of an alumina template which was subsequently removed by 2.0 M NaOH solution. They were characterized by XRD and FESEM. The immobilized AChE retained its biological activity and catalyzed the hydrolysis of acetylthiocholine to form thiocholine, which was subsequently oxidized to produce detectable signals. Based on the inhibition toward the enzymatic activity of AChE by OP insecticides, sensitive detection of methamidophos (an OP insecticide) was performed. Under optimal conditions, the sensors could be used for the determination of methamidophos ranging from 0.004 to 24 μg/mL with the detection limit of 0.001 μg/mL. The developed OP insecticide biosensors exhibited satisfactory stability and reproducibility. This work demonstrated that 1D Au nanoparticles could serve as an ideal carrier for immobilization of AChE to fabricate the corresponding biosensor.
Insecticide resistance mechanisms in the green peach aphid Myzus persicae (Hemiptera: Aphididae I: A transcriptomic survey.
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Andrea X Silva
Full Text Available BACKGROUND: Insecticide resistance is one of the best examples of rapid micro-evolution found in nature. Since the development of the first synthetic insecticide in 1939, humans have invested considerable effort to stay ahead of resistance phenotypes that repeatedly develop in insects. Aphids are a group of insects that have become global pests in agriculture and frequently exhibit insecticide resistance. The green peach aphid, Myzus persicae, has developed resistance to at least seventy different synthetic compounds, and different insecticide resistance mechanisms have been reported worldwide. METHODOLOGY/PRINCIPAL FINDINGS: To further characterize this resistance, we analyzed genome-wide transcriptional responses in three genotypes of M. persicae, each exhibiting different resistance mechanisms, in response to an anti-cholinesterase insecticide. The sensitive genotype (exhibiting no resistance mechanism responded to the insecticide by up-regulating 183 genes primarily ones related to energy metabolism, detoxifying enzymes, proteins of extracellular transport, peptidases and cuticular proteins. The second genotype (resistant through a kdr sodium channel mutation, up-regulated 17 genes coding for detoxifying enzymes, peptidase and cuticular proteins. Finally, a multiply resistant genotype (carrying kdr and a modified acetylcholinesterase, up-regulated only 7 genes, appears not to require induced insecticide detoxification, and instead down-regulated many genes. CONCLUSIONS/SIGNIFICANCE: This study suggests strongly that insecticide resistance in M. persicae is more complex that has been described, with the participation of a broad array of resistance mechanisms. The sensitive genotype exhibited the highest transcriptional plasticity, accounting for the wide range of potential adaptations to insecticides that this species can evolve. In contrast, the multiply resistant genotype exhibited a low transcriptional plasticity, even for the expression
Chromogenic platform based on recombinant Drosophila melanogaster acetylcholinesterase for visible unidirectional assay of organophosphate and carbamate insecticide residues
Energy Technology Data Exchange (ETDEWEB)
Han Zheng [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Chi Chensen [School of Life Science and Biotechnology, Bor Luh Food Safety Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Bai Bing; Liu Gang; Rao Qinxiong [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Peng Shaojie [Institute of Shanghai Food and Drug Supervision, 615 Liuzhou Road, Shanghai 200233 (China); Liu Hong [Shanghai Municipal Center for Disease Control and Prevention, 1380 Zhongshan West Road, Shanghai 200336 (China); Zhao Zhihui [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Zhang Dabing [School of Life Science and Biotechnology, Bor Luh Food Safety Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Wu Aibo, E-mail: email@example.com [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China)
Highlight: Black-Right-Pointing-Pointer A visible chromogenic platform for rapid analysis of OP and CM insecticide residues was developed. Black-Right-Pointing-Pointer The assay has the capabilities of both qualitative measurement and quantitative analysis. Black-Right-Pointing-Pointer The sensitivity, capabilities of resisting interferences and storage stability were desirable. Black-Right-Pointing-Pointer Matrix effects were acceptable and detection performance was satisfactory in real application. - Abstract: In this study we propose a chromogenic platform for rapid analysis of organophosphate (OP) and carbamate (CM) insecticide residues, based on recombinant Drosophila melanogaster acetylcholinesterase (R-DmAChE) as enzyme and indoxyl acetate as substrate. The visible chromogenic strip had the advantages identical to those of commonly used lateral flow assays (LFAs) with utmost simplicity in sample loading and result observation. After optimization, depending on the color intensity (CI) values, the well-established assay has the capabilities of both qualitative measurement via naked eyes and quantitative analysis by colorimetric reader with the desirable IC{sub 50} values against the tested six insecticides (0.06 {mu}g mL{sup -1} of carbofuran, 0.28 {mu}g mL{sup -1} of methomyl, 0.03 {mu}g mL{sup -1} of dichlorvos, 31.6 {mu}g mL{sup -1} of methamidophos, 2.0 {mu}g mL{sup -1} of monocrotophos, 6.3 {mu}g mL{sup -1} of omethoate). Acceptable matrix effects and satisfactory detection performance were confirmed by in-parallel LC-MS/MS analysis in different vegetable varieties at various spiked levels of 10{sup -3} to 10{sup 1} {mu}g g{sup -1}. Overall, the testified suitability and applicability of this novel platform meet the requirements for practical use in food safety management and environmental monitoring, especially in the developing world.
Insecticide Resistance Reducing Effectiveness of Malaria Control
Centers for Disease Control (CDC) Podcasts
Malaria prevention is increasingly insecticide based. Dr. John Gimnig, an entomologist with the Division of Parasitic Diseases, CDC, discusses evidence that mosquito resistance to insecticides, which is measured in the laboratory, could compromise malaria prevention in the field. Created: 1/24/2007 by Emerging Infectious Diseases. Date Released: 3/13/2007.
Insecticide resistance selection in rice planthoppers
Institute of Scientific and Technical Information of China (English)
@@ Brown planthopper (BPH, Nilaparvata lugens Stal) and white backed planthopper (WBPH, Sogatella furcifera Horvath) are the main insects on rice in China. The insecticide resistance of the two planthoppers have often been reported. Availability of the resistant population is a prerequisite for studying the resistance mechanism. In this paper, one method to select methamidophos resistance of the two planthoppers was recommended.
Cytochromes P450 and insecticide resistance.
Scott, J G
The cytochrome P450-dependent monooxygenases (monooxygenases) are an extremely important metabolic system involved in the catabolism and anabolism of xenobiotics and endogenous compounds. Monooxygenase-mediated metabolism is a common mechanism by which insects become resistant to insecticides as evidenced by the numerous insect species and insecticides affected. This review begins by presenting background information about P450s, the role of monooxygenases in insects, and the different techniques that have been used to isolate individual insect P450s. Next, insecticide resistance is briefly described, and then historical information about monooxygenase-mediated insecticide resistance is reviewed. For any case of monooxygenase-mediated resistance, identification of the P450(s) involved, out of the dozens that are present in an insect, has proven very challenging. Therefore, the next section of the review focuses on the minimal criteria for establishing that a P450 is involved in resistance. This is followed by a comprehensive examination of the literature concerning the individual P450s that have been isolated from insecticide resistant strains. In each case, the history of the strain and the evidence for monooxygenase-mediated resistance are reviewed. The isolation and characterization of the P450(s) from the strain are then described, and the evidence of whether or not the isolated P450(s) is involved in resistance is summarized. The remainder of the review summarizes our current knowledge of the molecular basis of monooxygenase-mediated resistance and the implications for the future. The importance of these studies for development of effective insecticide resistance management strategies is discussed.
Fitness costs associated with insecticide resistance.
Kliot, Adi; Ghanim, Murad
Insects are exposed to a variety of stress factors in their environment, and, in many cases for insect pests to agriculture, those factors include toxic chemical insecticides. Coping with the toxicity of insecticides can be costly and requires energy and resource allocation for adaptation and survival. Several behavioural, physiological and genetic mechanisms are used by insects to handle toxic insecticides, sometimes leading to resistance by constitutive overexpression of detoxification enzymes or inducing mutations in the target sites. Such actions are costly and may affect reproduction, impair dispersal ability and have several other effects on the insect's fitness. Fitness costs resulting from resistance to insecticides has been reported in many insects from different orders, and several examples are given in this mini-review.
acetylcholinesterase inhibitory potential and insecticidal activity of an endophytic Alternaria sp. from Ricinus communis.
Singh, Bahaderjeet; Thakur, Abhinay; Kaur, Sanehdeep; Chadha, B S; Kaur, Amarjeet
Keeping in view the vast potential of endophytic fungi to produce bioactive molecules, this study aimed at isolating and screening endophytes for the production of acetylcholinesterase inhibitors. Fifty-four endophytic fungi were isolated from Ricinus communis and screened for their AChE inhibitory activity using Ellman's colorimetric assay method. Six isolates were found to possess AChE inhibitory activity with maximum inhibition of 78 % being evinced by culture Cas1 which was identified to be Alternaria sp. on the basis of molecular as well as microscopic methods. Optimization of inhibitor production was carried out using one factor at a time approach. Maximum production of inhibitor was obtained on potato dextrose broth after 10 days incubation. The IC(50) of the chloroform extract was observed to be 40 μg/ml. The extract was purified on silica gel and eluted stepwise with a gradient of chloroform/methanol. The insecticidal potential of the extract was evaluated by feeding the larvae of Spodoptera litura on diet containing varying concentrations of the extract. It was observed that with increase in the concentration of the extract, mortality of the larvae increased. The culture has the potential of being exploited in medicine as well as a biocontrol agent.
Enzymatic characterization of insecticide resistance mechanisms in field populations of Malaysian Culex quinquefasciatus say (Diptera: Culicidae.
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Van Lun Low
Full Text Available BACKGROUND: There has been no comprehensive study on biochemical characterization of insecticide resistance mechanisms in field populations of Malaysian Culex quinquefasciatus. To fill this void in the literature, a nationwide investigation was performed to quantify the enzyme activities, thereby attempting to characterize the potential resistance mechanisms in Cx. quinquefasciatus in residential areas in Malaysia. METHODOLOGY/PRINCIPAL FINDINGS: Culex quinquefasciatus from 14 residential areas across 13 states and one federal territory were subjected to esterases, mixed function oxidases, glutathione-S-transferase and insensitive acetylcholinesterase assays. Enzyme assays revealed that α-esterases and β-esterases were elevated in 13 populations and 12 populations, respectively. Nine populations demonstrated elevated levels of mixed function oxidases and glutathione-S-transferase. Acetylcholinesterase was insensitive to propoxur in all 14 populations. Activity of α-esterases associated with malathion resistance was found in the present study. In addition, an association between the activity of α-esterases and β-esterases was also demonstrated. CONCLUSIONS/SIGNIFICANCE: The present study has characterized the potential biochemical mechanisms in contributing towards insecticide resistance in Cx. quinquefasciatus field populations in Malaysia. Identification of mechanisms underlying the insecticide resistance will be beneficial in developing effective mosquito control programs in Malaysia.
Salivary gland proteome analysis reveals modulation of anopheline unique proteins in insensitive acetylcholinesterase resistant Anopheles gambiae mosquitoes.
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Sylvie Cornelie
Full Text Available Insensitive acetylcholinesterase resistance due to a mutation in the acetylcholinesterase (ace encoding ace-1 gene confers cross-resistance to organophosphate and carbamate insecticides in Anopheles gambiae populations from Central and West Africa. This mutation is associated with a strong genetic cost revealed through alterations of some life history traits but little is known about the physiological and behavioural changes in insects bearing the ace-1(R allele. Comparative analysis of the salivary gland contents between An. gambiae susceptible and ace-1(R resistant strains was carried out to charaterize factors that could be involved in modifications of blood meal process, trophic behaviour or pathogen interaction in the insecticide-resistant mosquitoes. Differential analysis of the salivary gland protein profiles revealed differences in abundance for several proteins, two of them showing major differences between the two strains. These two proteins identified as saglin and TRIO are salivary gland-1 related proteins, a family unique to anopheline mosquitoes, one of them playing a crucial role in salivary gland invasion by Plasmodium falciparum sporozoites. Differential expression of two other proteins previously identified in the Anopheles sialome was also observed. The differentially regulated proteins are involved in pathogen invasion, blood feeding process, and protection against oxidation, relevant steps in the outcome of malaria infection. Further functional studies and insect behaviour experiments would confirm the impact of the modification of the sialome composition on blood feeding and pathogen transmission abilities of the resistant mosquitoes. The data supports the hypothesis of alterations linked to insecticide resistance in the biology of the primary vector of human malaria in Africa.
[Insecticide resistance mechanisms of Aedes aegypti (Diptera: Culicidae) from two Peruvian provinces].
Bisset, Juan A; Rodríguez, María; Fernández, Ditter; Palomino, Miriam
Insecticide resistance of Aedes aegypti larvae and adults from two Peruvian provinces, that is, Trujillo and Tumbes provinces, was conducted. High infestation indexes and extensive use of insecticides based on the Vector Surveillance and Control Strategy of the Ministry of Public Health prevailed in these places. Larval bioassays revealed susceptibility to organophosphorate insecticide called malathion in TRUJILLO strain, it being moderate to fention and fenitrotion and high to chlorpyriphos and temephos;however, TUMBES strain was susceptible to the evaluated organophosphorate compounds, except for fention, with moderate resistance. In the adult state, at the recommended dose, TRUJILLO strain showed resistence to DDT organochlorate insecticide and to pyrethoids called lambdacyalotrine and cyflutrine whereas TUMBES was resistant to DDT and to all assessed pyrethoids. None of them was resistant to chlorpiriphos in adult stage. By using synergists, the results showed that esterases and monooxigenases played an important role in the detected resistence to organophosphorate in Aedes larvae from TRUJILLO province. Biochemical assays yielded that increased activity of esterases was very frequent in TRUJILLO strain as was the case of glutathion transferase(GST) and modified acetylcholinesterase (AchR). On the other hand, the polyacrylamide gel electrophoresis allowed observing the prevalence of amplified activity of esterases A4 in TRUJILLO strain but not in TUMBES strain.
Insecticide Resistance: Challenge to Pest Management and Basic Research
Brattsten, L. B.; Holyoke, C. W.; Leeper, J. R.; Raffa, K. F.
The agricultural use of synthetic insecticides usually protects crops but imposes strong selection pressures that can result in the development of resistance. The most important resistance mechanisms are enhancement of the capacity to metabolically detoxify insecticides and alterations in target sites that prevent insecticides from binding to them. Insect control methods must incorporate strategies to minimize resistance development and preserve the utility of the insecticides. The most promising approach, integrated pest management, includes the use of chemical insecticides in combination with improved cultural and biologically based techniques.
Validating the importance of two acetylcholinesterases in insecticide sensitivities by RNAi in Pardosa pseudoannulata, an important predatory enemy against several insect pests.
Meng, Xiangkun; Li, Chunrui; Bao, Haibo; Fang, Jichao; Liu, Zewen; Zhang, Yixi
The pond wolf spider (Pardosa pseudoannulata) is an important predatory enemy against several insect pests and showed relative different sensitivities to organophosphate and carbamate insecticides compared to insect pests. In our previous studies, two acetylcholinesterases were identified in P. pseudoannulata and played important roles in insecticide sensitivities. In order to understand the contributions of the two acetylcholinesterases to insecticide sensitivities, we firstly employed the RNAi technology in the spider. For a suitable microinjection RNAi method, the injection site, injection volume and interference time were optimized, which then demonstrated that the injection RNAi method was applicable in this spider. With the new RNAi method, it was revealed that both Pp-AChE1 and Pp-AChE2, encoded by genes Ppace1 and Ppace2, were the targets of organophosphate insecticides, but Pp-AChE1 would be more important. In contrast, the carbamate acted selectively on Pp-AChE1. The results showed that Pp-AChE1 was the major catalytic enzyme in P. pseudoannulata and the major target of organophosphate and carbamate insecticides. In a word, an RNAi method was established in the pond wolf spider, which further validated the importance of two acetylcholinesterases in insecticide sensitivities in this spider.
Insecticide Resistance and Management Strategies in Urban Ecosystems
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Fang Zhu
Full Text Available The increased urbanization of a growing global population makes imperative the development of sustainable integrated pest management (IPM strategies for urban pest control. This emphasizes pests that are closely associated with the health and wellbeing of humans and domesticated animals. Concurrently there are regulatory requirements enforced to minimize inadvertent exposures to insecticides in the urban environment. Development of insecticide resistance management (IRM strategies in urban ecosystems involves understanding the status and mechanisms of insecticide resistance and reducing insecticide selection pressure by combining multiple chemical and non-chemical approaches. In this review, we will focus on the commonly used insecticides and molecular and physiological mechanisms underlying insecticide resistance in six major urban insect pests: house fly, German cockroach, mosquitoes, red flour beetle, bed bugs and head louse. We will also discuss several strategies that may prove promising for future urban IPM programs.
Insecticide resistance in the sand fly, Phlebotomus papatasi from Khartoum State, Sudan
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Hassan Mo'awia
Full Text Available Abstract Background Phlebotomus papatasi the vector of cutaneous leishmaniasis (CL is the most widely spread sand fly in Sudan. No data has previously been collected on insecticide susceptibility and/or resistance of this vector, and a first study to establish a baseline data is reported here. Methods Sand flies were collected from Surogia village, (Khartoum State, Rahad Game Reserve (eastern Sudan and White Nile area (Central Sudan using light traps. Sand flies were reared in the Tropical Medicine Research Institute laboratory. The insecticide susceptibility status of first progeny (F1 of P. papatasi of each population was tested using WHO insecticide kits. Also, P. papatasi specimens from Surogia village and Rahad Game Reserve were assayed for activities of enzyme systems involved in insecticide resistance (acetylcholinesterase (AChE, non-specific carboxylesterases (EST, glutathione-S-transferases (GSTs and cytochrome p450 monooxygenases (Cyt p450. Results Populations of P. papatasi from White Nile and Rahad Game Reserve were sensitive to dichlorodiphenyltrichloroethane (DDT, permethrin, malathion, and propoxur. However, the P. papatasi population from Surogia village was sensitive to DDT and permethrin but highly resistant to malathion and propoxur. Furthermore, P. papatasi of Surogia village had significantly higher insecticide detoxification enzyme activity than of those of Rahad Game Reserve. The sand fly population in Surogia displayed high AChE activity and only three specimens had elevated levels for EST and GST. Conclusions The study provided evidence for malathion and propoxur resistance in the sand fly population of Surogia village, which probably resulted from anti-malarial control activities carried out in the area during the past 50 years.
An Operational Framework for Insecticide Resistance Management Planning.
Chanda, Emmanuel; Thomsen, Edward K; Musapa, Mulenga; Kamuliwo, Mulakwa; Brogdon, William G; Norris, Douglas E; Masaninga, Freddie; Wirtz, Robert; Sikaala, Chadwick H; Muleba, Mbanga; Craig, Allen; Govere, John M; Ranson, Hilary; Hemingway, Janet; Seyoum, Aklilu; Macdonald, Michael B; Coleman, Michael
Arthropod vectors transmit organisms that cause many emerging and reemerging diseases, and their control is reliant mainly on the use of chemical insecticides. Only a few classes of insecticides are available for public health use, and the increased spread of insecticide resistance is a major threat to sustainable disease control. The primary strategy for mitigating the detrimental effects of insecticide resistance is the development of an insecticide resistance management plan. However, few examples exist to show how to implement such plans programmatically. We describe the formulation and implementation of a resistance management plan for mosquito vectors of human disease in Zambia. We also discuss challenges, steps taken to address the challenges, and directions for the future.
Averting a malaria disaster: will insecticide resistance derail malaria control?
Hemingway, Janet; Ranson, Hilary; Magill, Alan; Kolaczinski, Jan; Fornadel, Christen; Gimnig, John; Coetzee, Maureen; Simard, Frederic; Roch, Dabiré K; Hinzoumbe, Clément Kerah; Pickett, John; Schellenberg, David; Gething, Peter; Hoppé, Mark; Hamon, Nicholas
World Malaria Day 2015 highlighted the progress made in the development of new methods of prevention (vaccines and insecticides) and treatment (single dose drugs) of the disease. However, increasing drug and insecticide resistance threatens the successes made with existing methods. Insecticide resistance has decreased the efficacy of the most commonly used insecticide class of pyrethroids. This decreased efficacy has increased mosquito survival, which is a prelude to rising incidence of malaria and fatalities. Despite intensive research efforts, new insecticides will not reach the market for at least 5 years. Elimination of malaria is not possible without effective mosquito control. Therefore, to combat the threat of resistance, key stakeholders need to rapidly embrace a multifaceted approach including a reduction in the cost of bringing new resistance management methods to market and the streamlining of associated development, policy, and implementation pathways to counter this looming public health catastrophe.
Multiple-Insecticide Resistance and Classic Gene Mutations to Japanese Encephalitis Vector Culex tritaeniorhynchus from China.
Wu, Zhi-Ming; Chu, Hong-Liang; Wang, Gang; Zhu, Xiao-Juan; Guo, Xiao-Xia; Zhang, Ying-Mei; Xing, Dan; Yan, Ting; Zhao, Ming-Hui; Dong, Yan-De; Li, Chun-Xiao; Zhao, Tong-Yan
Widespread resistance of insect pests to insecticides has been widely reported in China and there is consequently an urgent need to adjust pest management strategies appropriately. This requires detailed information on the extent and causes of resistance. The aim of the present study was to investigate levels of resistance to 5 insecticides among 12 strains of Culex tritaeniorhynchus, a major vector of Japanese encephalitis in China. Resistance to deltamethrin, beta-cypermethrin, permethrin, dichlorvos, and propoxur were measured using larval bioassays. The allelic frequency of knockdown resistance (kdr) and acetylcholinesterase (AChE) mutations were determined in all strains. Larval bioassay results indicated that the field strains collected from different sites were resistant to deltamethrin, beta-cypermethrin, permethrin, dichlorvos, and propoxur, with resistance ratio values ranging from 1.70- to 71.98-fold, 7.83- to 43.07-fold, 3.54- to 40.03-fold, 291.85- to 530.89-fold, and 51.32- to 108.83-fold, respectively. A polymerase chain reaction amplification of specific alleles method for individual was developed to detect genotypes of the AChE gene mutation F455W in Cx. tritaeniorhynchus. The frequency of the AChE gene mutation F455W was 100.00% in all strains, making this mutation of no value as a marker of resistance to organophosphorous and carbamate pesticides in Cx. tritaeniorhynchus in China. The kdr allele was present in all strains at frequencies of 10.00-29.55%. Regression analysis indicated a significant correlation between kdr allele frequencies and levels of resistance to deltamethrin, beta-cypermethrin, and permethrin. These results highlight the need to monitor and map insecticide resistance in Cx. tritaeniorhynchus and to adjust pesticide use to minimize the development of resistance in these mosquitoes.
Mechanism of Insect Resistance to the Microbial Insecticide Bacillus thuringiensis
van Rie, J.; McGaughey, W. H.; Johnson, D. E.; Barnett, B. D.; van Mellaert, H.
Receptor binding studies show that resistance of a laboratory-selected Plodia interpunctella strain to a Bacillus thuringiensis insecticidal crystal protein (ICP) is correlated with a 50-fold reduction in affinity of the membrane receptor for this protein. The strain is sensitive to a second type of ICP that apparently recognizes a different receptor. Understanding the mechanism of resistance will provide strategies to prevent or delay resistance and hence prolong the usefulness of B. thuringiensis ICPs as environmentally safe insecticides.
The global status of insect resistance to neonicotinoid insecticides.
Bass, Chris; Denholm, Ian; Williamson, Martin S; Nauen, Ralf
The first neonicotinoid insecticide, imidacloprid, was launched in 1991. Today this class of insecticides comprises at least seven major compounds with a market share of more than 25% of total global insecticide sales. Neonicotinoid insecticides are highly selective agonists of insect nicotinic acetylcholine receptors and provide farmers with invaluable, highly effective tools against some of the world's most destructive crop pests. These include sucking pests such as aphids, whiteflies, and planthoppers, and also some coleopteran, dipteran and lepidopteran species. Although many insect species are still successfully controlled by neonicotinoids, their popularity has imposed a mounting selection pressure for resistance, and in several species resistance has now reached levels that compromise the efficacy of these insecticides. Research to understand the molecular basis of neonicotinoid resistance has revealed both target-site and metabolic mechanisms conferring resistance. For target-site resistance, field-evolved mutations have only been characterized in two aphid species. Metabolic resistance appears much more common, with the enhanced expression of one or more cytochrome P450s frequently reported in resistant strains. Despite the current scale of resistance, neonicotinoids remain a major component of many pest control programmes, and resistance management strategies, based on mode of action rotation, are of crucial importance in preventing resistance becoming more widespread. In this review we summarize the current status of neonicotinoid resistance, the biochemical and molecular mechanisms involved, and the implications for resistance management.
Resistance Status to the Insecticides Temephos, Deltamethrin, and Diflubenzuron in Brazilian Aedes aegypti Populations
Viana-Medeiros, Priscila Fernandes; Araújo, Simone Costa; Martins, Ademir J.; Lima, José Bento Pereira
Insecticides are still largely applied in public health to control disease vectors. In Brazil, organophosphates (OP) and pyrethroids (PY) are used against Aedes aegypti for years. Since 2009 Insect Growth Regulators (IGR) are also employed in the control of larvae. We quantified resistance to temephos (OP), deltamethrin (PY), and diflubenzuron (IGR) of A. aegypti samples from 12 municipalities distributed throughout the country, collected between 2010 and 2012. High levels of resistance to neurotoxic insecticides were detected in almost all populations: RR95 to temephos varied between 4.0 and 27.1; the lowest RR95 to deltamethrin was 13.1, and values higher than 70.0 were found. In contrast, all samples were susceptible to diflubenzuron (RR95 < 2.3). Biochemical tests performed with larvae and adults discarded the participation of acetylcholinesterase, the OP target, and confirmed involvement of the detoxifying enzymes esterases, mixed function oxidases, and glutathione-S-transferases. The results obtained were discussed taking into account the public chemical control component and the increase in the domestic use of insecticides during dengue epidemic seasons in the evaluated municipalities. PMID:27419140
Resistance Status to the Insecticides Temephos, Deltamethrin, and Diflubenzuron in Brazilian Aedes aegypti Populations
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Diogo Fernandes Bellinato
Full Text Available Insecticides are still largely applied in public health to control disease vectors. In Brazil, organophosphates (OP and pyrethroids (PY are used against Aedes aegypti for years. Since 2009 Insect Growth Regulators (IGR are also employed in the control of larvae. We quantified resistance to temephos (OP, deltamethrin (PY, and diflubenzuron (IGR of A. aegypti samples from 12 municipalities distributed throughout the country, collected between 2010 and 2012. High levels of resistance to neurotoxic insecticides were detected in almost all populations: RR95 to temephos varied between 4.0 and 27.1; the lowest RR95 to deltamethrin was 13.1, and values higher than 70.0 were found. In contrast, all samples were susceptible to diflubenzuron (RR95 < 2.3. Biochemical tests performed with larvae and adults discarded the participation of acetylcholinesterase, the OP target, and confirmed involvement of the detoxifying enzymes esterases, mixed function oxidases, and glutathione-S-transferases. The results obtained were discussed taking into account the public chemical control component and the increase in the domestic use of insecticides during dengue epidemic seasons in the evaluated municipalities.
Susceptibility to insecticides and resistance mechanisms in Aedes aegypti from the Colombian Caribbean Region.
Maestre-Serrano, Ronald; Gomez-Camargo, Doris; Ponce-Garcia, Gustavo; Flores, Adriana E
We determined the susceptibility to insecticides and the biochemical and molecular mechanisms involved in resistance in nine populations of Aedes aegypti (L.) of the Colombian Caribbean region. Bioassays were performed on larvae for susceptibility to temephos and on adults to the insecticides malathion, fenitrothion, pirimiphos-methyl, permethrin, deltamethrin, λ-cyhalothrin and cyfluthrin. The resistance ratio (RR) for each insecticide in the populations was determined, using the susceptible Rockefeller strain as a susceptible control. Additionally, we evaluated the response of the populations to the diagnostic dose (DD) of the organochlorine pesticide DDT. The following biochemical mechanisms associated with resistance were studied: α-esterases, β-esterases, mixed-function oxidases (MFO), glutathione s-transferases (GST) and insensitive acetylcholinesterase (iAChE) as well as the presence of kdr I1,016 mutation and its frequency. All populations studied showed susceptibility to the organophosphates evaluated (RR < 5-fold), except for the Puerto Colombia and Soledad populations which showed high resistance (RR 15-fold) and moderate resistance (RR 5-fold) to temephos, respectively, and Sincelejo (Sucre) with moderate resistance to pirimiphos-methyl (RR 5-fold). All populations evaluated with DD of DDT were found to be resistant with 2-28% of mortality. Variability was observed in the resistance to pyrethroids: permethrin (RR 1.2- to 30.8-fold), deltamethrin RR 0.9- to 37.8-fold), λ-cyalothrin (RR 3.4- to 83-fold) and cyfluthrin (RR 0.3- to 33.8-fold). Incipiently α-esterases and MFO levels were found in the Valledupar population; MFO showed the same profile in Cienaga and GST in the Sincelejo population, all other populations showed unaltered profiles of the enzymes evaluated. The kdr I1,016 mutation was found in all populations evaluated with variability in its allelic and genotypic frequencies.
Fungal infection counters insecticide resistance in African malaria mosquitoes
Farenhorst, M.; Mouatcho, J.C.; Kikankie, C.K.; Brooke, B.D.; Hunt, R.H.; Thomas, M.B.; Koekemoer, L.L.; Knols, B.G.J.; Coetzee, M.
The evolution of insecticide resistance in mosquitoes is threatening the effectiveness and sustainability of malaria control programs in various parts of the world. Through their unique mode of action, entomopathogenic fungi provide promising alternatives to chemical control. However, potential inte
Insecticide resistance in vector Chagas disease: evolution, mechanisms and management.
Mougabure-Cueto, Gastón; Picollo, María Inés
Chagas disease is a chronic parasitic infection restricted to America. The disease is caused by the protozoa Trypanosoma cruzi, which is transmitted to human through the feces of infected triatomine insects. Because no treatment is available for the chronic forms of the disease, vector chemical control represents the best way to reduce the incidence of the disease. Chemical control has been based principally on spraying dwellings with insecticide formulations and led to the reduction of triatomine distribution and consequent interruption of disease transmission in several areas from endemic region. However, in the last decade it has been repeatedly reported the presence triatomnes, mainly Triatoma infestans, after spraying with pyrethroid insecticides, which was associated to evolution to insecticide resistance. In this paper the evolution of insecticide resistance in triatomines is reviewed. The insecticide resistance was detected in 1970s in Rhodnius prolixus and 1990s in R. prolixus and T. infestans, but not until the 2000s resistance to pyrthroids in T. infestans associated to control failures was described in Argentina and Bolivia. The main resistance mechanisms (i.e. enhanced metabolism, altered site of action and reduced penetration) were described in the T. infestans resistant to pyrethrods. Different resistant profiles were demonstrated suggesting independent origin of the different resistant foci of Argentina and Bolivia. The deltamethrin resistance in T. infestans was showed to be controlled by semi-dominant, autosomally inherited factors. Reproductive and developmental costs were also demonstrated for the resistant T. infestans. A discussion about resistance and tolerance concepts and the persistence of T. infestans in Gran Chaco region are presented. In addition, theoretical concepts related to toxicological, evolutionary and ecological aspects of insecticide resistance are discussed in order to understand the particular scenario of pyrethroid
Insecticide Resistance in the Western Flower Thrips, Frankliniella occidentalis
DEFF Research Database (Denmark)
Jensen, Sten Erik
The western flower thrips, Frankliniella occidentalis (Pergande) is a serious pest on a wide range of crops throughout the world. In Denmark F. occidentalis is a pest in greenhouses. F. occidentalis is difficult to control with insecticides because of its thigmokinetic behaviour and resistance...... to insecticides. Since F. occidentulis spread to become a worldwide pest in 1980'es, resistance to a number of different insecticides has been shown in many populations of F. occidentalis. This flower thrips has the potential of fast development of resistance owing to the short generation time, high fecundity......, and a haplodiploid breeding system. Although resistance in F. occidentalis is a common problem, the underlying mechanisms conferring resistance have only been studied on a few populations. A purpose of this study was to gain more knowledge about possible resistance mechanisms in F. occidentulis and, furthermore...
Selection of insensitive acetylcholinesterase as a resistance mechanism in Aedes aegypti (Diptera: Culicidae) from Santiago de Cuba.
Bisset, Juan; Rodríguez, María M; Fernández, Ditter
A sample of Aedes aegypti (L.) (Diptera: Culicidae) from Santiago de Cuba, Cuba, with a high level of propoxur resistance compared with the reference susceptible Rockefeller strain (12.60 x at the 50% lethal concentration [LC50] and 18.08 at the 90% lethal concentration [LC90]), with a 4.3% frequency of insensitive acetylcholinesterase (AChE) frequency, was subjected to propoxur selection for 13 successive generations to increase the frequency of this resistance mechanism in Ae. aegypti. High resistance to propoxur was developed during this selection (41.73-fold), and the frequency of insensitive AChE mechanism was increased 13.25-fold. Other mechanisms (overproduced esterases, glutathione transferases, or monooxygenases) were not detected in the propoxur-selected strain. The selection of an insensitive AChE resistance mechanism in Ae. aegypti has important implications and will be a valuable resource for genetic studies and molecular characterization of the ace gene mutation(s) associated with insecticide resistance in Ae. aegypti.
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Full Text Available Introduction. Toxaphene is resistant to degration and has been known as persistent bioaccumulator. In oder to understand the persistence and degradation phenomena of toxaphene in soil a series of tests were run. Methods. All experiments for dry and moist soil were conducted with 10 to 20 kg soil samples, contained in plastic tubs. The experiment was carried out in two parts. The five samples studied in each part are described below. Part I: "Dry samples". Soil control I soil amended with 10 percent gin trash/soil amended with 25 percent gin trash/soil amended with 10 percent gin trash and treated with 500 ppm toxaphene and soil treated with 500 ppm toxaphene. These samples were kept dry during the entire experimental period. Part II: "Moist samples". The samples were the same as described in part I, but they were kept moist by addition of water weekly during the experimental period. Periodically twenty grams of soil were analyzed using a gas chromatograph. Results. Chromatograms of dry and moist samples from soil containers (Part I and II analyzed up to 12 months after initiation of the experiments showed that no toxaphene degradation or dissipation had occurred. GLC profiles of extracts of 12 months soil samples were identical to those of 0 dry samples and almost 100 percent of toxaphene was recovered in all samples after one year regardless of whether samples were dry or moist I amended or not. Discussion. The results suggest that toxaphene dose not undergo degradation in soil" under aerobic condition, so it can be a persistent insecticide in soil under environmental condition.
Underpinning sustainable vector control through informed insecticide resistance management.
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Edward K Thomsen
Full Text Available BACKGROUND: There has been rapid scale-up of malaria vector control in the last ten years. Both of the primary control strategies, long-lasting pyrethroid treated nets and indoor residual spraying, rely on the use of a limited number of insecticides. Insecticide resistance, as measured by bioassay, has rapidly increased in prevalence and has come to the forefront as an issue that needs to be addressed to maintain the sustainability of malaria control and the drive to elimination. Zambia's programme reported high levels of resistance to the insecticides it used in 2010, and, as a result, increased its investment in resistance monitoring to support informed resistance management decisions. METHODOLOGY/PRINCIPAL FINDINGS: A country-wide survey on insecticide resistance in Zambian malaria vectors was performed using WHO bioassays to detect resistant phenotypes. Molecular techniques were used to detect target-site mutations and microarray to detect metabolic resistance mechanisms. Anopheles gambiae s.s. was resistant to pyrethroids, DDT and carbamates, with potential organophosphate resistance in one population. The resistant phenotypes were conferred by both target-site and metabolic mechanisms. Anopheles funestus s.s. was largely resistant to pyrethroids and carbamates, with potential resistance to DDT in two locations. The resistant phenotypes were conferred by elevated levels of cytochrome p450s. CONCLUSIONS/SIGNIFICANCE: Currently, the Zambia National Malaria Control Centre is using these results to inform their vector control strategy. The methods employed here can serve as a template to all malaria-endemic countries striving to create a sustainable insecticide resistance management plan.
The insecticide resistance in stripped stem borer, Chilo suppressalis (Walker)
Institute of Scientific and Technical Information of China (English)
@@ The stripped stem borer (SSB), Chilo suppressalis (Walker) is one of the major insect pests of rice in China. Chemical control has been a common practice in SSB management since 1950s. Insecticides used included BHC before 1983;organophosphorus insecticides (methyl-parathion, trichophon, methamidophos, and monocrotophos), and chlordimeform in mid-1970s-1980s; Shachongshuang (dimehypo) and Shachongdan (monousltap) since early 1980s. In recent years, SSB population and its damage to rice increased rapidly and failures on control has been reported. To find out the cause of failure and to put forward the suitable control methods, we studied the resistance of SSB to major insecticides used in China.
The insecticide resistance in two planthoppers from three areas to three insecticides
Institute of Scientific and Technical Information of China (English)
@@ Migrating insects brown planthopper (BPH), Nilaparata lugens Stal and white-backed planthopper (WBPH), Sogatellafurcifera Horvath are both most harmful insects on rice in China. Chemical control is thought to be the best way to manage them, but it may cause insecticide resistance.
Multiple insecticide resistance mechanisms involving metabolic changes and insensitive target sites selected in anopheline vectors of malaria in Sri Lanka
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Karunaratne SHP Parakrama
Full Text Available Abstract Background The current status of insecticide resistance and the underlying resistance mechanisms were studied in the major vector of malaria, Anopheles culicifacies, and the secondary vector, Anopheles subpictus in five districts (Anuradhapura, Kurunegala, Moneragala, Puttalam and Trincomalee of Sri Lanka. Eight other anophelines, Anopheles annularis, Anopheles barbirostris, Anopheles jamesii, Anopheles nigerrimus, Anopheles peditaeniatus, Anopheles tessellatus, Anopheles vagus and Anopheles varuna from Anuradhapura district were also tested. Methods Adult females were exposed to the WHO discriminating dosages of DDT, malathion, fenitrothion, propoxur, λ-cyhalothrin, cyfluthrin, cypermethrin, deltamethrin, permethrin and etofenprox. The presence of metabolic resistance by esterase, glutathione S-transferase (GST and monooxygenase-based mechanisms, and the sensitivity of the acetylcholinesterase target site were assessed using synergists, and biochemical, and metabolic techniques. Results All the anopheline species had high DDT resistance. All An. culicifacies and An. subpictus populations were resistant to malathion, except An. culicifacies from Kurunegala, where there was no malathion carboxylesterase activity. Kurunegala and Puttalam populations of An. culicifacies were susceptible to fenitrothion. All the An. culicifacies populations were susceptible to carbamates. Both species were susceptible to the discriminating dosages of cypermethrin and cyfluthrin, but had different levels of resistance to other pyrethroids. Of the 8 other anophelines, only An. nigerrimus and An. peditaeniatus were resistant to all the insecticides tested, probably due to their high exposure to the insecticides used in agriculture. An. vagus showed some resistance to permethrin. Esterases, GSTs and monooxygenases were elevated in both An. culicifacies and An. subpictus. AChE was most sensitive to insecticides in Kurunegala and Trincomalee An. culicifacies
Evaluation of Insecticide Resistance and Biochemical Mechanisms in a Population of Culex quinquefasciatus (Diptera: Culicidae from São Paulo, Brazil
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Bracco José Eduardo
Full Text Available To establish an insecticidal resistance surveillance program, Culex quinquefasciatus mosquitoes from São Paulo, Brazil, were colonized (PIN95 strain and analyzed for levels of resistance. The PIN95 strain showed low levels of resistance to organophosphates [malathion (3.3-fold, fenitrothion (11.2-fold] and a carbamate [propoxur (3.0-fold]. We also observed an increase of 7.4 and 9.9 in a and b esterase activities, respectively, when compared with the reference IAL strain. An alteration in the sensitivity of acetylcholinesterase to insecticide inhibition was also found in the PIN95 mosquitoes. The resistant allele (Ace.1R, however, was found at low frequencies (0.12 and does not play an important role in the described insecticide resistance. One year later, Cx. quinquefasciatus mosquitoes were collected (PIN96 strain at the same site and compared to the PIN95 strain. The esterase activity patterns observed for the PIN96 strain were similar to those of the PIN95 mosquitoes. However the occurrence of the Ace.1R allele was statistically higher in the PIN96 strain. The results show that esterase-based insecticide resistance was established in the PIN95 Cx. quinquefasciatus population and that an acethylcholinesterase based resistant mechanism has been selected for. A continuous monitoring of this phenomenon is fundamental for rational mosquito control and insecticide application programs.
Resistance to bio-insecticides or how to enhance their sustainability: a review.
Siegwart, Myriam; Graillot, Benoit; Blachere Lopez, Christine; Besse, Samantha; Bardin, Marc; Nicot, Philippe C; Lopez-Ferber, Miguel
After more than 70 years of chemical pesticide use, modern agriculture is increasingly using biological control products. Resistances to conventional insecticides are wide spread, while those to bio-insecticides have raised less attention, and resistance management is frequently neglected. However, a good knowledge of the limitations of a new technique often provides greater sustainability. In this review, we compile cases of resistance to widely used bio-insecticides and describe the associated resistance mechanisms. This overview shows that all widely used bio-insecticides ultimately select resistant individuals. For example, at least 27 species of insects have been described as resistant to Bacillus thuringiensis toxins. The resistance mechanisms are at least as diverse as those that are involved in resistance to chemical insecticides, some of them being common to bio-insecticides and chemical insecticides. This analysis highlights the specific properties of bio-insecticides that the scientific community should use to provide a better sustainability of these products.
Changes in insecticide resistance of the rice striped stem borer (Lepidoptera: Crambidae).
Su, Jianya; Zhang, Zhenzhen; Wu, Min; Gao, Congfen
Application of insecticides is the most important method to control Chilo suppressalis (Walker) (Lepidoptera: Crambidae), and continuous use of individual insecticides has driven the rapid development of insecticide resistance in C. suppressalis during the past 30 yr. Monitoring insecticide resistance provides information essential for integrated pest management. Insecticide resistance of field populations to monosultap, triazophos, chlorpyrifos, and abamectin in China was examined in 2010 and 2011. The results indicated that the resistance levels of 14 field populations to four insecticides were significantly different. Four populations showed moderate resistance, and other populations possessed low-level resistance or were susceptible to monosultap. Nine populations displayed an extremely high or a high level of resistance to triazophos, whereas four populations were sensitive to this agent. Five populations exhibited a low level of resistance to abamectin, while the others remained sensitive. When compared with historical data, resistance to monosultap and triazophos decreased significantly, and the percentage of populations with high-level or extremely high-level resistance was obviously reduced. By contrast, the resistance to abamectin increased slightly. The increasing and decreasing resistance levels reported in this study highlight the different evolutionary patterns of insecticide resistance in C. suppressalis. An overreliance on one or two insecticides may promote rapid development of resistance. Slow development of resistance to abamectin, which was used mainly in mixtures with other insecticides, implies that the use of insecticide mixtures may be an effective method to delay the evolution of resistance to insecticides.
Insecticide resistance status in Anopheles gambiae in southern Benin
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Corbel Vincent
Full Text Available Abstract Background The emergence of pyrethroid resistance in Anopheles gambiae has become a serious concern to the future success of malaria control. In Benin, the National Malaria Control Programme has recently planned to scaling up long-lasting insecticidal nets (LLINs and indoor residual spraying (IRS for malaria prevention. It is, therefore, crucial to monitor the level and type of insecticide resistance in An. gambiae, particularly in southern Benin where reduced efficacy of insecticide-treated nets (ITNs and IRS has previously been reported. Methods The protocol was based on mosquito collection during both dry and rainy seasons across forty districts selected in southern Benin. Bioassay were performed on adults collected from the field to assess the susceptibility of malaria vectors to insecticide-impregnated papers (permethrin 0.75%, delthamethrin 0.05%, DDT 4%, and bendiocarb 0.1% following WHOPES guidelines. The species within An. gambiae complex, molecular form and presence of kdr and ace-1 mutations were determined by PCR. Results Strong resistance to permethrin and DDT was found in An. gambiae populations from southern Benin, except in Aglangandan where mosquitoes were fully susceptible (mortality 100% to all insecticides tested. PCR showed the presence of two sub-species of An. gambiae, namely An. gambiae s.s, and Anopheles melas, with a predominance for An. gambiae s.s (98%. The molecular M form of An. gambiae was predominant in southern Benin (97%. The kdr mutation was detected in all districts at various frequency (1% to 95% whereas the Ace-1 mutation was found at a very low frequency (≤ 5%. Conclusion This study showed a widespread resistance to permethrin in An. gambiae populations from southern Benin, with a significant increase of kdr frequency compared to what was observed previously in Benin. The low frequency of Ace-1 recorded in all populations is encouraging for the use of bendiocarb as an alternative insecticide to
Multiple Mutations on the Second Acetylcholinesterase Gene Associated With Dimethoate Resistance in the Melon Aphid, Aphis gossypii (Hemiptera: Aphididae).
Lokeshwari, D; Krishna Kumar, N K; Manjunatha, H
The melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is an important cosmopolitan and extremely polyphagous species capable of causing direct and indirect damage to various crops. Insecticide resistance in melon aphids is of particular concern. To determine the basis of resistance, organophosphate (OP)-resistant strains of A. gossypii were obtained by continuous selection with dimethoate in the laboratory, and resistance mechanisms were investigated along with susceptible strains. Three resistant strains LKR-1, LKR-2, and LKR-3 exhibiting 270-, 243-, and 210-fold resistance obtained after 30 generations of selection with dimethoate, respectively, were utilized in this study. The role of acetylcholinesterase (AChE), a target enzyme for OPs and carbamates (CMs), was investigated. AChE enzyme assay revealed that there was no significant change in the activities of AChE in resistant and susceptible strains. However, AChE inhibitory assay showed that 50% of the enzyme activity in resistant strains was inhibited at significantly higher concentration of dimethoate (131.87, 158.65, and 99.29 µmolL(−1)) as compared with susceptible strains (1.75 and 2.01 µmolL(−1)), indicating AChE insensitivity owing to altered AChE. Molecular diagnostic tool polymerase chain reaction-restriction fragment length polymorphism revealed the existence of two consistent non-synonymous point mutations, single-nucleotide polymorphism, viz., A302S (equivalent to A201 in Torpedo californica Ayres) and S431F (equivalent to F331 in T. californica), in the AChE gene Ace2 of resistant strains. Further, cloning and sequencing of a partial fragment of Ace2 (897 bp) gene from susceptible and resistant strains revealed an additional novel mutation G221A in resistant strains, LKR-1 and LKR-2. Susceptible Ace2 genes shared 99.6 and 98.9% identity at the nucleic acid and amino acid levels with resistant ones, respectively. Functional analysis of these point mutations was assessed by in
Insecticide resistance in Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) and Anopheles gambiae Giles (Diptera: Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa.
Gnankiné, Olivier; Bassolé, Imael H N; Chandre, Fabrice; Glitho, Isabelle; Akogbeto, Martin; Dabiré, Roch K; Martin, Thibaud
Insecticides from the organophosphate (OP) and pyrethroid (PY) chemical families, have respectively, been in use for 50 and 30 years in West Africa, mainly against agricultural pests, but also against vectors of human disease. The selection pressure, with practically the same molecules year after year (mainly on cotton), has caused insecticide resistance in pest populations such as Bemisia tabaci, vector of harmful phytoviruses on vegetables. The evolution toward insecticide resistance in malaria vectors such as Anopheles gambiae sensus lato (s.l.) is probably related to the current use of these insecticides in agriculture. Thus, successful pest and vector control in West Africa requires an investigation of insect susceptibility, in relation to the identification of species and sub species, such as molecular forms or biotypes. Identification of knock down resistance (kdr) and acetylcholinesterase gene (Ace1) mutations modifying insecticide targets in individual insects and measure of enzymes activity typically involved in insecticide metabolism (oxidase, esterase and glutathion-S-transferase) are indispensable in understanding the mechanisms of resistance. Insecticide resistance is a good example in which genotype-phenotype links have been made successfully. Insecticides used in agriculture continue to select new resistant populations of B. tabaci that could be from different biotype vectors of plant viruses. As well, the evolution of insecticide resistance in An. gambiae threatens the management of malaria vectors in West Africa. It raises the question of priority in the use of insecticides in health and/or agriculture, and more generally, the question of sustainability of crop protection and vector control strategies in the region. Here, we review the susceptibility tests, biochemical and molecular assays data for B. tabaci, a major pest in cotton and vegetable crops, and An. gambiae, main vector of malaria. The data reviewed was collected in Benin and Burkina
Impact of three years of large scale Indoor Residual Spraying (IRS and Insecticide Treated Nets (ITNs interventions on insecticide resistance in Anopheles gambiae s.l. in Benin
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Padonou Gil
Full Text Available Abstract Background In Benin, Indoor Residual Spraying (IRS and long-lasting insecticidal nets (LLINs are the cornerstones of malaria prevention. In the context of high resistance of Anopheles gambiae to pyrethroids, The National Malaria Control Program (NMCP has undertaken a full coverage of IRS in a no-flood zone in the Oueme region, coupled with the distribution of LLINs in a flood zone. We assessed the impact of this campaign on phenotypic resistance, kdr (knock-down resistance and ace-1R (insensitive acetylcholinesterase mutations. Methods Insecticides used for malaria vector control interventions were bendiocarb WP (0.4 g/m2 and deltamethrin (55 mg/m2, respectively for IRS and LLINs. Susceptibility status of An. gambiae was assessed using World Health Organization bioassay tests to DDT, permethrin, deltamethrin and bendiocarb in the Oueme region before intervention (2007 and after interventions in 2008 and 2010. An. gambiae specimens were screened for identification of species, molecular M and S forms and for the detection of the West African kdr (L1014F as well as ace-1R mutations using PCR techniques. Results The univariate logistic regression performed showed that kdr frequency has increased significantly during the three years in the intervention area and in the control area. Several factors (LLINs, IRS, mosquito coils, aerosols, use of pesticides for crop protection could explain the selection of individual resistant An. gambiae. The Kdr resistance gene could not be the only mechanism of resistance observed in the Oueme region. The high susceptibility to bendiocarb is in agreement with a previous study conducted in Benin. However, the occurrence of ace-1R heterozygous individuals even on sites far from IRS areas, suggests other factors may contribute to the selection of resistance other than those exerted by the vector control program. Conclusion The results of this study have confirmed that An.gambiae have maintained and developed
Insecticide resistance and its molecular basis in urban insect pests.
Naqqash, Muhammad Nadir; Gökçe, Ayhan; Bakhsh, Allah; Salim, Muhammad
Insecticide resistance is one of the most important evolutionary phenomena for researchers. Overuse of chemicals has induced resistance in insect pests that ultimately has led to the collapse of disease control programs in many countries. The erroneous and inappropriate management of insect vectors has resulted in dissemination of many vector-borne diseases like dengue, malaria, diarrhea, leishmaniasis, and many others. In most cases, the emergence of new diseases and the revival of old ones can be related with ecological changes that have favored rapid growth of vector densities. Understanding molecular mechanisms in resistant strains can assist in the development of management programs to control the development and spread of resistant insect populations. The dominant, recessive, and co-dominant forms of genes encoding resistance can be investigated, and furthermore, resistance development can be addressed either by the release of susceptible strains or timely insecticide rotation. The present review discusses the resistance level in all important insect vectors of human diseases; the molecular basis of evolvement of resistance has also been discussed.
Zhakhongirov, Sh M; Saifiev, Sh T; Abidov, Z I
The resistance of Anopheles artemievi to DDT (26.7%) and propoxur (80.0%) was established in the kishlak of Chubat, Bulungursky District, Samarkand Viloyati and that in the kishlak of Rastguzar, Uichinsky District, Namangan Viloyati, was 45.0 and 22.5%, respectively. In the kishlak of Navruz, Kanlikulsky District, Republic of Karakalpakstan, there was reduced propoxur susceptibil- ity (90.0% An. superpictus death); in other human settle- ments, An. artemievi was susceptible--100% death in the use of the test insecticides. An. superpictus proved to be susceptive to 7 test insecticides (other than propoxur). In Uzbekistan, the resistance of An. artemievi was noted only in a small area. Among the major malaria vectors, An. superpictus remained susceptible to pyrethroid insec- ticides.
Characterization of acetylcholinesterases, and their genes, from the hemipteran species Myzus persicae (Sulzer), Aphis gossypii (Glover), Bemisia tabaci (Gennadius) and Trialeurodes vaporariorum (Westwood).
Javed, N; Viner, R; Williamson, M S; Field, L M; Devonshire, A L; Moores, G D
Gene sequences encoding putative acetylcholinesterases have been reported for four hemipteran insect species. Although acetylcholinesterase insensitivity occurs in insecticide-resistant populations of each of these species, no mutations were detected in the gene sequences from the resistant insects. This, coupled with a series of experiments using novel reversible inhibitors to compare the biochemical characteristics of acetylcholinesterase from a range of insect species, showed that the cloned cDNA fragments are unlikely to encode the hemipteran synaptic acetylcholinesterases, and there is likely to be a second ace locus.
Efficacy of an insecticide paint against insecticide-susceptible and resistant mosquitoes - Part 1: Laboratory evaluation
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Carnevale Pierre
Full Text Available Abstract Background The main malaria vector Anopheles gambiae and the urban pest nuisance Culex quinquefasciatus are increasingly resistant to pyrethroids in many African countries. There is a need for new products and strategies. Insecticide paint Inesfly 5A IGR™, containing two organophosphates (OPs, chlorpyrifos and diazinon, and insect growth regulator (IGR, pyriproxyfen, was tested under laboratory conditions for 12 months following WHOPES Phase I procedures. Methods Mosquitoes used were laboratory strains of Cx. quinquefasciatus susceptible and resistant to OPs. The paint was applied at two different doses (1 kg/6 m2 and 1 kg/12 m2 on different commonly used surfaces: porous (cement and stucco and non-porous (softwood and hard plastic. Insecticide efficacy was studied in terms of delayed mortality using 30-minute WHO bioassay cones. IGR efficacy on fecundity, fertility and larval development was studied on OP-resistant females exposed for 30 minutes to cement treated and control surfaces. Results After treatment, delayed mortality was high (87-100% even against OP-resistant females on all surfaces except cement treated at 1 kg/12 m2. Remarkably, one year after treatment delayed mortality was 93-100% against OP-resistant females on non-porous surfaces at both doses. On cement, death rates were low 12 months after treatment regardless of the dose and the resistance status. Fecundity, fertility and adult emergence were reduced after treatment even at the lower dose (p -3. A reduction in fecundity was still observed nine months after treatment at both doses (p -3 and adult emergence was reduced at the higher dose (p -3. Conclusions High mortality rates were observed against laboratory strains of the pest mosquito Cx. quinquefasciatus susceptible and resistant to insecticides. Long-term killing remained equally important on non-porous surfaces regardless the resistance status for over 12 months. The paint's effect on fecundity, fertility and
Laboratory development of permethrin resistance and cross-resistance pattern of Culex quinquefasciatus to other insecticides.
Ramkumar, Govindaraju; Shivakumar, Muthugoundar S
Resistance of mosquitoes to insecticides is a growing concern in India. Since only a few insecticides are used for public health and limited development of new molecules is expected in the next decade, maintaining the efficacy of control programs mostly relies on resistance management strategies. Developing such strategies requires a deep understanding of factors influencing resistance together with characterizing the mechanisms involved. Among factors likely to influence insecticide resistance in mosquitoes, agriculture and urbanization have been implicated but rarely studied in detail. In the present study, we evaluate the permethrin resistance and cross-resistance pattern of several insecticides in Culex quinquefasciatus mosquitoes. After 10 generation of selection with permethrin, the LC50 value for both larvae and adult Cx. quinquefasciatus was increased by 17.3- and 17.1-folds compared with susceptible strain. Detoxification enzyme profiles and native PAGE electrophoresis of esterase isoenzyme further revealed that esterase and CytP450 may be involved in permethrin resistance (PerRes) strain compared with susceptible strain. In addition to cross-resistance, study revealed that high resistance to cypermethrin (RR = 6.3, 8.8-folds). This study provided important information for understanding permethrin resistance and facilitating a better strategy for the management of resistance. These studies conclude that a strong foundation for further study of permethrin resistance mechanisms observed in Cx. quinquefasciatus mosquitoes.
Managing insecticide resistance by mass release of engineered insects.
Alphey, Nina; Coleman, Paul G; Donnelly, Christl A; Alphey, Luke
Transgenic crops producing insecticidal toxins are now widely used to control insect pests. The benefits of this method would be lost if resistance to the toxins spread to a significant proportion of the pest population. The primary resistance management method, mandatory in the United States, is the high-dose/ refuge strategy, requiring toxin-free crops as refuges near the insecticidal crops, and the use of toxin doses sufficiently high to kill insects heterozygous for a resistance allele, thereby rendering resistance functionally recessive. We propose that mass-release of harmless susceptible (toxin-sensitive) insects could substantially delay or even reverse the spread of resistance. Mass-release of such insects is an integral part of release of insects carrying a dominant lethal (RIDL), a method of pest control related to the sterile insect technique. We show by mathematical modeling that specific RIDL strategies could form an effective component of a resistance management strategy for plant-incorporated protectants and other toxins.
Resistance is not Futile: It Shapes Insecticide Discovery
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Margaret C. Hardy
Full Text Available Conventional chemical control compounds used for the management of insect pests have been much maligned, but still serve a critical role in protecting people and agricultural products from insect pests, as well as conserving biodiversity by eradicating invasive species. Although biological control can be an effective option for area-wide management of established pests, chemical control methods are important for use in integrated pest management (IPM programs, as well as in export treatments, eradicating recently arrived invasive species, and minimizing population explosions of vectors of human disease. Cogitated research and development programs have continued the innovation of insecticides, with a particular focus on combating insecticide resistance. Recent developments in the fields of human health, protecting the global food supply, and biosecurity will be highlighted.
Toxicity, synergism, and neurological effects of novel volatile insecticides in insecticide-susceptible and -resistant Drosophila strains.
Nguyen, Sam N; Song, Cheol; Scharf, Michael E
Naturally derived volatile insecticides from the heterobicyclic and formate ester classes were investigated using a combination of volatility and synergist bioassays. In these studies, Drosophila melanogaster (Meigen) was used as a model for other medically important dipterans. In addition to a susceptible strain (Canton-S), three mutant strains were tested that included a strain resistant by P450-based metabolism (Hikone-R) and two resistant neurological mutant strains; one voltage-gated sodium channel mutant (para(ts-1)) and one GABA-gated chloride channel mutant (Rdl). In general, the 11 tested insecticides displayed a diversity of toxicity, metabolism, and resistance characteristics that correlate with their structural diversity. Several important trends were revealed by these studies, including hydrolase- and cytochrome P450 (P450)-based activation, P450-based resistance, distinct patterns of neurological activity, and negative cross-resistance with established insecticides. These findings provide important insight into the metabolism and modes of action for the volatile insecticides. These findings also suggest potential approaches for insecticide deployment in integrated vector management and resistance management programs.
Insecticide resistance to organophosphates in Culex pipiens complex from Lebanon
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Osta Mike A
Full Text Available Abstract Background Analysis of Culex pipiens mosquitoes collected from a single site in Lebanon in 2005, revealed an alarming frequency of ace-1 alleles conferring resistance to organophosphate insecticides. Following this, in 2006 the majority of municipalities switched to pyrethroids after a long history of organophosphate usage in the country; however, since then no studies have assessed the impact of changing insecticide class on the frequency of resistant ace-1 alleles in C. pipiens. Methods C. pipiens mosquitoes were captured indoors from 25 villages across the country and subjected to established methods for the analysis of gene amplification at the Ester locus and target site mutations in ace-1 gene that confer resistance to organophosphates. Results We conducted the first large-scale screen for resistance to organosphosphates in C. pipiens mosquitoes collected from Lebanon. The frequency of carboxylesterase (Ester and ace-1 alleles conferring resistance to organophosphates were assessed among C. pipiens mosquitoes collected from 25 different villages across the country between December 2008 and December 2009. Established enzymatic assay and PCR-based molecular tests, both diagnostic of the major target site mutations in ace-1 revealed the absence of the F290V mutation among sampled mosquitoes and significant reduction in the frequency of G119S mutation compared to that previously reported for mosquitoes collected from Beirut in 2005. We also identified a new duplicated ace-1 allele, named ace-1D13, exhibiting a resistant phenotype by associating a susceptible and a resistant copy of ace-1 in a mosquito line sampled from Beirut in 2005. Fisher's exact test on ace-1 frequencies in the new sample sites, showed that some populations exhibited a significant excess of heterozygotes, suggesting that the duplicated allele is still present. Starch gel electrophoresis indicated that resistance at the Ester locus was mainly attributed to the
CYP6 P450 enzymes and ACE-1 duplication produce extreme and multiple insecticide resistance in the malaria mosquito Anopheles gambiae.
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Constant V Edi
Full Text Available Malaria control relies heavily on pyrethroid insecticides, to which susceptibility is declining in Anopheles mosquitoes. To combat pyrethroid resistance, application of alternative insecticides is advocated for indoor residual spraying (IRS, and carbamates are increasingly important. Emergence of a very strong carbamate resistance phenotype in Anopheles gambiae from Tiassalé, Côte d'Ivoire, West Africa, is therefore a potentially major operational challenge, particularly because these malaria vectors now exhibit resistance to multiple insecticide classes. We investigated the genetic basis of resistance to the most commonly-applied carbamate, bendiocarb, in An. gambiae from Tiassalé. Geographically-replicated whole genome microarray experiments identified elevated P450 enzyme expression as associated with bendiocarb resistance, most notably genes from the CYP6 subfamily. P450s were further implicated in resistance phenotypes by induction of significantly elevated mortality to bendiocarb by the synergist piperonyl butoxide (PBO, which also enhanced the action of pyrethroids and an organophosphate. CYP6P3 and especially CYP6M2 produced bendiocarb resistance via transgenic expression in Drosophila in addition to pyrethroid resistance for both genes, and DDT resistance for CYP6M2 expression. CYP6M2 can thus cause resistance to three distinct classes of insecticide although the biochemical mechanism for carbamates is unclear because, in contrast to CYP6P3, recombinant CYP6M2 did not metabolise bendiocarb in vitro. Strongly bendiocarb resistant mosquitoes also displayed elevated expression of the acetylcholinesterase ACE-1 gene, arising at least in part from gene duplication, which confers a survival advantage to carriers of additional copies of resistant ACE-1 G119S alleles. Our results are alarming for vector-based malaria control. Extreme carbamate resistance in Tiassalé An. gambiae results from coupling of over-expressed target site allelic
CYP6 P450 enzymes and ACE-1 duplication produce extreme and multiple insecticide resistance in the malaria mosquito Anopheles gambiae.
Edi, Constant V; Djogbénou, Luc; Jenkins, Adam M; Regna, Kimberly; Muskavitch, Marc A T; Poupardin, Rodolphe; Jones, Christopher M; Essandoh, John; Kétoh, Guillaume K; Paine, Mark J I; Koudou, Benjamin G; Donnelly, Martin J; Ranson, Hilary; Weetman, David
Malaria control relies heavily on pyrethroid insecticides, to which susceptibility is declining in Anopheles mosquitoes. To combat pyrethroid resistance, application of alternative insecticides is advocated for indoor residual spraying (IRS), and carbamates are increasingly important. Emergence of a very strong carbamate resistance phenotype in Anopheles gambiae from Tiassalé, Côte d'Ivoire, West Africa, is therefore a potentially major operational challenge, particularly because these malaria vectors now exhibit resistance to multiple insecticide classes. We investigated the genetic basis of resistance to the most commonly-applied carbamate, bendiocarb, in An. gambiae from Tiassalé. Geographically-replicated whole genome microarray experiments identified elevated P450 enzyme expression as associated with bendiocarb resistance, most notably genes from the CYP6 subfamily. P450s were further implicated in resistance phenotypes by induction of significantly elevated mortality to bendiocarb by the synergist piperonyl butoxide (PBO), which also enhanced the action of pyrethroids and an organophosphate. CYP6P3 and especially CYP6M2 produced bendiocarb resistance via transgenic expression in Drosophila in addition to pyrethroid resistance for both genes, and DDT resistance for CYP6M2 expression. CYP6M2 can thus cause resistance to three distinct classes of insecticide although the biochemical mechanism for carbamates is unclear because, in contrast to CYP6P3, recombinant CYP6M2 did not metabolise bendiocarb in vitro. Strongly bendiocarb resistant mosquitoes also displayed elevated expression of the acetylcholinesterase ACE-1 gene, arising at least in part from gene duplication, which confers a survival advantage to carriers of additional copies of resistant ACE-1 G119S alleles. Our results are alarming for vector-based malaria control. Extreme carbamate resistance in Tiassalé An. gambiae results from coupling of over-expressed target site allelic variants with
Highly Sensitive Detection of Organophosphate Insecticides Using Biosensors Based on Genetically Engineered Acetylcholinesterase and Poly(3,4-Ethylenedioxythiophene
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Tomasz Sikora
Full Text Available A poly(3,4-ethylenedioxythiophene (PEDOT conducting ink is presented as a new electroactive material to be incorporated in acetylcholinesterase-(AChE- based screen printed biosensors, acting not only as a conducting template but also as an electrochemical mediator for thiocholine oxidation. Two different strategies have been studied for the chemical synthesis of PEDOT: (a a classical oxidative polymerisation and (b a more innovative enzymatic polymerisation, giving a water-soluble PEDOT. The use of this water-soluble conducting polymer as mediator in screen-printed biosensors enables its deposition by printing like the rest of the layers. Highly sensitive acetylcholinesterase-(AChE- based screen-printed biosensors have been constructed using both classical and enzymatic PEDOT, in combination with genetically modified AChE. These electrodes allow the measurement of thiocholine oxidation at potentials of 100 mV versus Ag/AgCl reference electrode through the mediation of PEDOT. Inhibition of thiocholine production in presence of CPO allow for detection of this pesticide in concentrations as low as 1·10−10 M.
Insecticide applications to soil contribute to the development of Burkholderia mediating insecticide resistance in stinkbugs.
Tago, Kanako; Kikuchi, Yoshitomo; Nakaoka, Sinji; Katsuyama, Chie; Hayatsu, Masahito
Some soil Burkholderia strains are capable of degrading the organophosphorus insecticide, fenitrothion, and establish symbiosis with stinkbugs, making the host insects fenitrothion-resistant. However, the ecology of the symbiotic degrading Burkholderia adapting to fenitrothion in the free-living environment is unknown. We hypothesized that fenitrothion applications affect the dynamics of fenitrothion-degrading Burkholderia, thereby controlling the transmission of symbiotic degrading Burkholderia from the soil to stinkbugs. We investigated changes in the density and diversity of culturable Burkholderia (i.e. symbiotic and nonsymbiotic fenitrothion degraders and nondegraders) in fenitrothion-treated soil using microcosms. During the incubation with five applications of pesticide, the density of the degraders increased from less than the detection limit to around 10(6)/g of soil. The number of dominant species among the degraders declined with the increasing density of degraders; eventually, one species predominated. This process can be explained according to the competitive exclusion principle using V(max) and K(m) values for fenitrothion metabolism by the degraders. We performed a phylogenetic analysis of representative strains isolated from the microcosms and evaluated their ability to establish symbiosis with the stinkbug Riptortus pedestris. The strains that established symbiosis with R. pedestris were assigned to a cluster including symbionts commonly isolated from stinkbugs. The strains outside the cluster could not necessarily associate with the host. The degraders in the cluster predominated during the initial phase of degrader dynamics in the soil. Therefore, only a few applications of fenitrothion could allow symbiotic degraders to associate with their hosts and may cause the emergence of symbiont-mediated insecticide resistance.
The insecticide resistance status of malaria vectors in the Mekong region
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Denis Leen
Full Text Available Abstract Background Knowledge on insecticide resistance in target species is a basic requirement to guide insecticide use in malaria control programmes. Malaria transmission in the Mekong region is mainly concentrated in forested areas along the country borders, so that decisions on insecticide use should ideally be made at regional level. Consequently, cross-country monitoring of insecticide resistance is indispensable to acquire comparable baseline data on insecticide resistance. Methods A network for the monitoring of insecticide resistance, MALVECASIA, was set up in the Mekong region in order to assess the insecticide resistance status of the major malaria vectors in Cambodia, Laos, Thailand, and Vietnam. From 2003 till 2005, bioassays were performed on adult mosquitoes using the standard WHO susceptibility test with diagnostic concentrations of permethrin 0.75% and DDT 4%. Additional tests were done with pyrethroid insecticides applied by the different national malaria control programmes. Results Anopheles dirus s.s., the main vector in forested malaria foci, was susceptible to permethrin. However, in central Vietnam, it showed possible resistance to type II pyrethroids. In the Mekong delta, Anopheles epiroticus was highly resistant to all pyrethroid insecticides tested. It was susceptible to DDT, except near Ho Chi Minh City where it showed possible DDT resistance. In Vietnam, pyrethroid susceptible and tolerant Anopheles minimus s.l. populations were found, whereas An. minimus s.l. from Cambodia, Laos and Thailand were susceptible. Only two An. minimus s.l. populations showed DDT tolerance. Anopheles vagus was found resistant to DDT and to several pyrethroids in Vietnam and Cambodia. Conclusion This is the first large scale, cross-country survey of insecticide resistance in Anopheles species in the Mekong Region. A unique baseline data on insecticide resistance for the Mekong region is now available, which enables the follow-up of trends
抗药性与敏感性德国小蠊乙酰胆碱酶的活性比较%A comparative study on the activity of acetylcholinesterase in the pesticides resistant strains of Blattella germanica
Institute of Scientific and Technical Information of China (English)
王式春; 林琳; 刘渠; 张起文; 沈培林; 韦薇; 王德全
目的 研究德国小蠊抗药性与乙酰胆碱酯酶活性的关系.方法 采用化学比色方法对敏感品系和抗性品系的德国小蠊分别测试乙酰胆碱酯酶,对比两者的测定值,分析抗性品系和敏感品系德国小蠊乙酰胆碱酯酶的差异.结果 敏感品系和抗性品系德国小蠊的乙酰胆碱酯酶活性分别是2.863和5.609,抗性品系德国小蠊酶活性显著高于敏感品系,两者酶活性比值为1.96.结论 乙酰胆碱酯酶活性与德国小蠊抗药性有关.%Objective To study the activity of acetylcholinesterase (AChE) in insecticide resistant German cockroaches.Methods Different strains and gender of German cockroaches were used in this study. Colorimetric method was used to determine the activity of acetylcholinesternse. Results Blattella germanica were studied for their acetylcholinesterase activity.AChE activity in the insecticide resistant and insecticide sensitive strains was 2.863 and 5.609, respectively. AChE activity of the field strain was significantly higher than the susceptible strain. And the ratio of AChE activity between the resistant and the sensitive strain was 1.96. Conclusion The activity of AChE from the field strains was correlated with the pesticides resistance.
Synergy in efficacy of fungal entomopathogens and permethrin against West African insecticide-resistant Anopheles gambiae mosquitoes
Farenhorst, M.; Knols, B.G.J.; Thomas, M.B.; Howard, A.F.V.; Takken, W.; Rowland, M.; N'Guessan, R.
Background Increasing incidences of insecticide resistance in malaria vectors are threatening the sustainable use of contemporary chemical vector control measures. Fungal entomopathogens provide a possible additional tool for the control of insecticide-resistant malaria mosquitoes. This study invest
Adulticidal & larvicidal efficacy of three neonicotinoids against insecticide susceptible & resistant mosquito strains
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Sreehari Uragayala
Interpretation & conclusions: The present study indicated that insecticide resistant strains of mosquito species tested showed more susceptibility to the three neonicotinoids tested, and the possibility of using neonicotinoids for the control of resistant mosquitoes should be explored.
Insecticidal properties of essential oils against Tribolium castaneum (Herbst) and their inhibitory effects on acetylcholinesterase and adenosine triphosphatases.
Abou-Taleb, Hamdy K; Mohamed, Magdy I E; Shawir, Mohamed S; Abdelgaleil, Samir A M
Essential oils from 20 Egyptian plants were obtained by using hydrodistillation. The chemical composition of the isolated oils was identified by gas chromatograph/mass spectrometer. Fumigant and contact toxicities of the essential oils were evaluated against the adults of Tribolium castaneum. In fumigation assays, the oil of Origanum vulgare (LC50 = 9.97 mg/L air) displayed the highest toxicity towards the adults of T. castaneum. In contact assays, the oils of Artemisia monosperma (LC50 = 0.07 mg/cm(2)) and O. vulgare (LC50 = 0.07 mg/cm(2)) were the most potent toxicants against the adults of T. castaneum. Biochemical studies showed that the tested oils caused pronounced inhibition of acetylcholinesterase (AChE) and adenosine triphosphatases (ATPases) isolated from the larvae of T. castaneum. The oil Cupressus macrocarpa (IC50 = 12.3 mg/L) was the most potent inhibitor of AChE, while the oil of Calistemon viminals (IC50 = 4.4 mg/L) was the most potent inhibitor of ATPases.
A comparative study on the relationship between acetylcholinesterase activity and acute toxicity in Daphnia magna exposed to anticholinesterase insecticides.
Printes, Liane Biehl; Callaghan, Amanda
Acetylcholinesterase (AChE) activity was measured in Daphnia magna that had been exposed to four organophosphates (OPs; parathion, chlorpyrifos, malathion, and acephate) and one carbamate (propoxur) for 48 h. These results were related to acute toxicity (median effective concentration [EC50] for immobility). For the four OPs, the EC50s were 7.03 pM, 3.17 pM, 10.56 pM, and 309.82 microM, respectively. The EC50 for propoxur was 449.90 pM. Reduction in AChE activity was directly related to an increase in immobility in all chemicals tested. However, the ratio between the EC50 and the AChE median inhibiting concentration ranged from 0.31 to 0.90. A 50% reduction in AChE activity generally was associated with detrimental effects on mobility. However, for acephate, high levels of AChE inhibition (70%) were observed in very low concentrations and were not associated with immobility. In addition, increasing the concentration of acephate further had a slight negative effect on AChE activity but a strong detrimental effect on mobility. Binding sites other than AChE possibly are involved in acephate toxicity to D. magna. Our findings demonstrate different associations between AChE inhibition and toxicity when different chemicals are compared. Therefore, the value of using AChE activity as a biomarker in D. magna will be dependent on the chemical tested.
Role of cytochrome P450s in insecticide resistance: impact on the control of mosquito-borne diseases and use of insecticides on Earth.
David, Jean-Philippe; Ismail, Hanafy Mahmoud; Chandor-Proust, Alexia; Paine, Mark John Ingraham
The fight against diseases spread by mosquitoes and other insects has enormous environmental, economic and social consequences. Chemical insecticides remain the first line of defence but the control of diseases, especially malaria and dengue fever, is being increasingly undermined by insecticide resistance. Mosquitoes have a large repertoire of P450s (over 100 genes). By pinpointing the key enzymes associated with insecticide resistance we can begin to develop new tools to aid the implementation of control interventions and reduce their environmental impact on Earth. Recent technological advances are helping us to build a functional profile of the P450 determinants of insecticide metabolic resistance in mosquitoes. Alongside, the cross-responses of mosquito P450s to insecticides and pollutants are also being investigated. Such research will provide the means to produce diagnostic tools for early detection of P450s linked to resistance. It will also enable the design of new insecticides with optimized efficacy in different environments.
Evolution of insecticide resistance in non-target black flies (Diptera: Simuliidae from Argentina
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Cristina Mónica Montagna
Full Text Available Black flies, a non-target species of the insecticides used in fruit production, represent a severe medical and veterinary problem. Large increases in the level of resistance to the pyrethroids fenvalerate (more than 355-fold and deltamethrin (162-fold and a small increase in resistance to the organophosphate azinphos methyl (2-fold were observed between 1996-2008 in black fly larvae under insecticide pressure. Eventually, no change or a slight variation in insecticide resistance was followed by a subsequent increase in resistance. The evolution of pesticide resistance in a field population is a complex and stepwise process that is influenced by several factors, the most significant of which is the insecticide selection pressure, such as the dose and frequency of application. The variation in insecticide susceptibility within a black fly population in the productive area may be related to changes in fruit-pest control. The frequency of individuals with esterase activities higher than the maximum value determined in the susceptible population increased consistently over the sampling period. However, the insecticide resistance was not attributed to glutathione S-transferase activity. In conclusion, esterase activity in black flies from the productive area is one mechanism underlying the high levels of resistance to pyrethroids, which have been recently used infrequently. These enzymes may be reselected by currently used pesticides and enhance the resistance to these insecticides.
An amperometric biosensor based on acetylcholinesterase immobilized onto iron oxide nanoparticles/multi-walled carbon nanotubes modified gold electrode for measurement of organophosphorus insecticides
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Chauhan, Nidhi [Department of Biochemistry, M.D. University, Rohtak 124001, Haryana (India); Pundir, Chandra Shekhar, E-mail: email@example.com [Department of Biochemistry, M.D. University, Rohtak 124001, Haryana (India)
Graphical abstract: The stepwise amperometric biosensor fabrication process and immobilized acetylcholinesterase inhibition in pesticide solution. Highlights: {center_dot} Constructed a novel composite material using Fe{sub 3}O{sub 4}NP and c-MWCNT at Au electrode for electrocatalysis. {center_dot} The properties of nanoparticles modified electrodes were studied by SEM, FTIR, CVs and EIS. {center_dot} The biosensor exhibited good sensitivity (0.475 mA {mu}M{sup -1}) {center_dot} The half life of electrode was 2 months. {center_dot} The sensor was suitable for trace detection of OP pesticide residues in milk and water. - Abstract: An acetylcholinesterase (AChE) purified from maize seedlings was immobilized covalently onto iron oxide nanoparticles (Fe{sub 3}O{sub 4}NP) and carboxylated multi walled carbon nanotubes (c-MWCNT) modified Au electrode. An organophosphorus (OP) biosensor was fabricated using this AChE/Fe{sub 3}O{sub 4}/c-MWCNT/Au electrode as a working electrode, Ag/AgCl as standard and Pt wire as an auxiliary electrode connected through a potentiostat. The biosensor was based on inhibition of AChE by OP compounds/insecticides. The properties of nanoparticles modified electrodes were studied by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), cyclic voltammograms (CVs) and electrochemical impedance spectroscopy (EIS). The synergistic action of Fe{sub 3}O{sub 4}NP and c-MWCNT showed excellent electrocatalytic activity at low potential (+0.4 V). The optimum working conditions for the sensor were pH 7.5, 35 deg. C, 600 {mu}M substrate concentration and 10 min for inhibition by pesticide. Under optimum conditions, the inhibition rates of OP pesticides were proportional to their concentrations in the range of 0.1-40 nM, 0.1-50 nM, 1-50 nM and 10-100 nM for malathion, chlorpyrifos, monocrotophos and endosulfan respectively. The detection limits were 0.1 nM for malathion and chlorpyrifos, 1 nM for monocrotophos and 10 nM for endosulfan. The
蚊虫抗药性分子机制研究进展%Advances in the molecular mechanisms of mosquito resistance to insecticides
Institute of Scientific and Technical Information of China (English)
刘宏美; 代玉华; 公茂庆
蚊虫是重要的医学昆虫,可以通过叮咬传播疾病(例如疟疾、丝虫病、登革热等),其行为与人类生活息息相关.由于长久以来大量、广泛地使用杀虫剂,使蚊虫抗性日益严重.蚊虫的抗性机制主要有靶标抗性(包括神经轴突钠离子通道、乙酰胆碱酯酶和γ-氨基丁酸受体氯离子通道的突变)和代谢抗性(包括非特异性羧酸酯酶、细胞色素P450和谷胱甘肽-S-转移酶的活性增加)两方面.现对这些机制的研究进展进行综述,试图全面了解大量、广泛使用杀虫剂之后蚊虫抗性产生的分子机制.%Mosquitoes, which act as important medical insects, can transmit diseases such as malaria, fiariasis and dengue fever, etc. by bites, being harmful to humans. For a long period of time, due to the extensive use of chemical insecticides, the insecticide resistance in mosquitoes is becoming more and more serious. The mechanisms of resistance can be classified into two groups, knockdown resistance (such as saltations in sodium channel, Acetylcholinesterase and 7-aminobutyric acid) and metabolic resistance (such as augmentations in carboxylesterase, cytochrome P450 and glutathione-S-transferase). In this article, recent research advances in the resistance of mosquitoes to chemical insecticides are reviewed for better understanding of the molecular mechanism of mosquito resistance to the extensively used chemical insecticides.
Resistance Monitoring for Eight Insecticides on the Sweetpotato Whitefly (Hemiptera: Aleyrodidae) in China.
Wang, Shaoli; Zhang, Youjun; Yang, Xin; Xie, Wen; Wu, Qingjun
The sweetpotato whitefly, Bemisia tabaci (Gennadius), is an important pest of many crops worldwide. Because control of B. tabaci still depends on the application of insecticides in China, monitoring the insecticide resistance of B. tabaci populations is essential for achieving control and for managing resistance. In this study, field populations of B. tabaci on vegetables were collected in three regions of China in 2011, 2012, and 2013. The resistance of these populations (all of which were determined to belong to biotype Q) to eight insecticides (abamectin, spinetoram, imidacloprid, thiamethoxam, acetamiprid, nitenpyram, chlorpyrifos, and bifenthrin) was assessed by the leaf-dip method. No resistance to abamectin and spinetoram was detected. All of the B. tabaci populations exhibited resistance to neonicotinoid insecticides; the resistance was 3.6- to 125.0-fold greater than that of a susceptible reference strain. The traditional insecticides chlorpyrifos and bifenthrin had very low toxicity. Bemisia tabaci specimens in some regions exhibited annual differences in resistance to some of the insecticides. The data presented will be helpful for making decisions on the proper insecticide usage in the field.
Development of Resistance to Pyrethroid in Culex pipiens pallens Population under Different Insecticide Selection Pressures.
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Linna Shi
Full Text Available Current vector control programs are largely dependent on pyrethroids, which are the most commonly used and only insecticides recommended by the World Health Organization for insecticide-treated nets (ITNs. However, the rapid spread of pyrethroid resistance worldwide compromises the effectiveness of control programs and threatens public health. Since few new insecticide classes for vector control are anticipated, limiting the development of resistance is crucial for prolonging efficacy of pyrethroids. In this study, we exposed a field-collected population of Culex pipiens pallens to different insecticide selection intensities to dynamically monitor the development of resistance. Moreover, we detected kdr mutations and three detoxification enzyme activities in order to explore the evolutionary mechanism of pyrethroid resistance. Our results revealed that the level of pyrethroid resistance was proportional to the insecticide selection pressure. The kdr and metabolic resistance both contributed to pyrethroid resistance in the Cx. pipiens pallens populations, but they had different roles under different selection pressures. We have provided important evidence for better understanding of the development and mechanisms of pyrethroid resistance which may guide future insecticide use and vector management in order to avoid or delay resistance.
Development of Resistance to Pyrethroid in Culex pipiens pallens Population under Different Insecticide Selection Pressures.
Shi, Linna; Hu, Hongxia; Ma, Kai; Zhou, Dan; Yu, Jing; Zhong, Daibin; Fang, Fujin; Chang, Xuelian; Hu, Shengli; Zou, Feifei; Wang, Weijie; Sun, Yan; Shen, Bo; Zhang, Donghui; Ma, Lei; Zhou, Guofa; Yan, Guiyun; Zhu, Changliang
Current vector control programs are largely dependent on pyrethroids, which are the most commonly used and only insecticides recommended by the World Health Organization for insecticide-treated nets (ITNs). However, the rapid spread of pyrethroid resistance worldwide compromises the effectiveness of control programs and threatens public health. Since few new insecticide classes for vector control are anticipated, limiting the development of resistance is crucial for prolonging efficacy of pyrethroids. In this study, we exposed a field-collected population of Culex pipiens pallens to different insecticide selection intensities to dynamically monitor the development of resistance. Moreover, we detected kdr mutations and three detoxification enzyme activities in order to explore the evolutionary mechanism of pyrethroid resistance. Our results revealed that the level of pyrethroid resistance was proportional to the insecticide selection pressure. The kdr and metabolic resistance both contributed to pyrethroid resistance in the Cx. pipiens pallens populations, but they had different roles under different selection pressures. We have provided important evidence for better understanding of the development and mechanisms of pyrethroid resistance which may guide future insecticide use and vector management in order to avoid or delay resistance.
Insecticide resistance in bedbugs in Thailand and laboratory evaluation of insecticides for the control of Cimex hemipterus and Cimex lectularius (Hemiptera: Cimicidae).
Tawatsin, Apiwat; Thavara, Usavadee; Chompoosri, Jakkrawarn; Phusup, Yutthana; Jonjang, Nisarat; Khumsawads, Chayada; Bhakdeenuan, Payu; Sawanpanyalert, Pathom; Asavadachanukorn, Preecha; Mulla, Mir S; Siriyasatien, Padet; Debboun, Mustapha
Bedbugs are found in many countries around the world, and in some regions they are resistant to numerous insecticides. This study surveyed bedbugs in Thailand and determined their resistance to insecticides. The surveys were carried out in six provinces that attract large numbers of foreign tourists: Bangkok, Chonburi, Chiang Mai, Ubon Ratchathani, Phuket, and Krabi. Bedbugs were collected from hotels and colonized in the laboratory to evaluate their resistance to insecticides. Cimex hemipterus (F.) was found in some hotels in Bangkok, Chonburi, Phuket, and Krabi, whereas Cimex lectularius L. was found only in hotels in Chiang Mai. No bedbugs were found in Ubon Ratchathani. The colonized bedbugs showed resistance to groups of insecticides, including organochlorines (dichlorodiphenyl trichloroethane, dieldrin), carbamates (bendiocarb, propoxur), organophosphates (malathion, fenitrothion), and pyrethroids (cyfluthrin, deltamethrin, permethrin, lambda-cyhalothrin, etofenprox) in tests using World Health Organization insecticide-impregnated papers. The new insecticides imidacloprid (neonicotinoid group), chlorfenapyr (pyrrole group), and fipronil (phenylpyrazole group) were effective against the bedbugs; however, organophosphate (diazinon), carbamates (fenobucarb, propoxur), and pyrethroids (bifenthrin, cypermethrin, esfenvalerate, etofenprox) were ineffective. Aerosols containing various pyrethroid insecticides with two to four different active ingredients were effective against the bedbugs. The results obtained from this study suggested that both species of bedbugs in Thailand have developed marked resistance to various groups of insecticides, especially those in the pyrethroid group, which are the most common insecticides used for pest control. Therefore, an integrated pest management should be implemented for managing bedbugs in Thailand.
Indirect evidence that agricultural pesticides select for insecticide resistance in the malaria vector Anopheles gambiae.
Luc, Djogbénou S; Benoit, Assogba; Laurette, Djossou; Michel, Makoutode
We investigated the possible relationship between the agricultural use of insecticides and the emergence of insecticide resistance. Bioassays were conducted using simulated mosquito larval habitats and well known Anopheles gambiae strains. Soil samples were collected from vegetable production areas in Benin, including one site with insecticide use, one site where insecticides had not been used for two months, and a third where insecticides had not been used. Pupation and emergence rates were very low in pyrethroid-susceptible strains when exposed to soil that had been recently exposed to insecticides. Pupation and emergence rates in strains with the kdr mutation alone or both the kdr and Ace-1 mutations were much higher. Overall, strains with the kdr mutation survived at higher rates compared to that without kdr mutation. Although this study is observational, we provide indirect evidence indicating that soils from agricultural areas contain insecticide residues that can play a role in the emergence of insecticide resistance in Anopheles. This aspect should be taken into account to better utilize the insecticide in the context of integrated pest management programs.
Carboxylesterase-mediated insecticide resistance: Quantitative increase induces broader metabolic resistance than qualitative change.
Cui, Feng; Li, Mei-Xia; Chang, Hai-Jing; Mao, Yun; Zhang, Han-Ying; Lu, Li-Xia; Yan, Shuai-Guo; Lang, Ming-Lin; Liu, Li; Qiao, Chuan-Ling
Carboxylesterases are mainly involved in the mediation of metabolic resistance of many insects to organophosphate (OP) insecticides. Carboxylesterases underwent two divergent evolutionary events: (1) quantitative mechanism characterized by the overproduction of carboxylesterase protein; and (2) qualitative mechanism caused by changes in enzymatic properties because of mutation from glycine/alanine to aspartate at the 151 site (G/A151D) or from tryptophan to leucine at the 271 site (W271L), following the numbering of Drosophila melanogaster AChE. Qualitative mechanism has been observed in few species. However, whether this carboxylesterase mutation mechanism is prevalent in insects remains unclear. In this study, wild-type, G/A151D and W271L mutant carboxylesterases from Culex pipiens and Aphis gossypii were subjected to germline transformation and then transferred to D. melanogaster. These germlines were ubiquitously expressed as induced by tub-Gal4. In carboxylesterase activity assay, the introduced mutant carboxylesterase did not enhance the overall carboxylesterase activity of flies. This result indicated that G/A151D or W271L mutation disrupted the original activities of the enzyme. Less than 1.5-fold OP resistance was only observed in flies expressing A. gossypii mutant carboxylesterases compared with those expressing A. gossypii wild-type carboxylesterase. However, transgenic flies universally showed low resistance to OP insecticides compared with non-transgenic flies. The flies expressing A. gossypii W271L mutant esterase exhibited 1.5-fold resistance to deltamethrin, a pyrethroid insecticide compared with non-transgenic flies. The present transgenic Drosophila system potentially showed that a quantitative increase in carboxylesterases induced broader resistance of insects to insecticides than a qualitative change.
Resistance of Dusky Cotton Bug, Oxycarenus hyalinipennis Costa (Lygaidae: Hemiptera), to Conventional and Novel Chemistry Insecticides.
Ullah, Saif; Shad, Sarfraz Ali; Abbas, Naeem
The dusky cotton bug, Oxycarenus hyalinipennis Costa (Lygaidae: Hemiptera), is polyphagous in nature and has become one of the severe sucking pests of cotton in Pakistan. O. hyalinipennis has the potential to develop resistance to a number of insecticides, and as a result, O. hyalinipennis outbreaks occur. There is no previous study from Pakistan regarding O. hyalinipennis resistance to insecticides. Therefore, the aim of this study was to assess the resistance of different field populations of O. hyalinipennis to conventional (bifenthrin, deltamethrin, lambda-cyhalothrin, profenofos, triazophos) and novel chemistry (emamectin benzoate, spinosad, chlorfenapyr, imidacloprid, and nitenpyram) insecticides. Five populations of O. hyalinipennis, collected from Multan, Khanewal, Muzaffargarh, Lodhran, and Bahawalpur, were tested for resistance to selected insecticides by the leaf dip method. For three pyrethroids, the resistance ratios were in the range of 14- to 30-fold for bifenthrin, 2.14- to 8.41-fold for deltamethrin, and 9.12- to 16-fold for lambda-cyhalothrin, compared with the laboratory susceptible strain (Lab-PK). For two organophosphates, the range of resistance ratios was 12- to 14-fold for profenofos and 9.04- to 15-fold for triazophos. For five novel chemistry insecticides, the range of resistance ratios was 4.68- to 9.83-fold for emamectin benzoate, 6.38- to 17-fold for spinosad, 16- to 46-fold for chlorfenapyr, 11- to 22-fold for imidacloprid, and 1.32- to 11-fold for nitenpyram. Regular assessment of resistance to insecticides and integrated management plans like judicious use of insecticides and rotation of insecticides along with different modes of action are required to delay resistance development in O. hyalinipennis.
Mitochondrial P-glycoprotein ATPase contributes to insecticide resistance in the cotton bollworm, Helicoverpa armigera (Noctuidae: Lepidoptera).
Akbar, S Md; Aurade, Ravindra M; Sharma, H C; Sreeramulu, K
Cotton bollworm, Helicoverpa armigera, is one of the most damaging polyphagous pests worldwide, which has developed high levels of resistance to commonly applied insecticides. Mitochondrial P-glycoprotein (Pgp) was detected in the insecticide-resistant strain of H. armigera using C219 antibodies, and its possible role was demonstrated in the efflux of xenobiotic compounds using spectrofluorometer. The TMR accumulated in mitochondria in the absence of ATP, and effluxed out in presence of ATP; the process of efflux was inhibited in the presence of ortho-vandate, an inhibitor of Pgp, in insecticide-resistant larvae of H. armigera. The mitochondria isolated from insecticide-resistant larvae were resistant to insecticide-induced inhibition of oxygen consumption and cytochrome c release. Membrane potential decreased in a dose-dependent manner in the presence of higher concentration of insecticides (>50 µM) in mitochondria of insecticide-resistant larvae. In conclusion, mitochondrial Pgp ATPase detected in the insecticide-resistant larvae influenced the efflux of xenobiotic compounds. Pgp might be involved in protecting the mitochondrial DNA and the components of the electron transport chain from damage due to insecticides, and contributing to the resistance to the deleterious effects of insecticides on the growth of insecticide-resistant H. armigera larvae.
The impact of insecticides management linked with resistance expression in Anopheles spp. populations
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Guilherme Liberato da Silva
Full Text Available Abstract The resistance of some species of Anopheles to chemical insecticides is spreading quickly throughout the world and has hindered the actions of prevention and control of malaria. The main mechanism responsible for resistance in these insects appears to be the target site known as knock-down resistance (kdr, which causes mutations in the sodium channel. Even so, many countries have made significant progress in the prevention of malaria, focusing largely on vector control through long-lasting insecticide nets (LLINs, indoor residual spraying and (IRS of insecticides. The objective of this review is to contribute with information on the more applied insecticides for the control of the main vectors of malaria, its effects, and the different mechanisms of resistance. Currently it is necessary to look for others alternatives, e.g. biological control and products derived from plants and fungi, by using other organisms as a possible regulator of the populations of malaria vectors in critical outbreaks.
Acetylcholinesterase of the Sand Fly, Phlebotomus papatasi (Scopoli): Construction, Expression and Biochemical Properties of the G119S Orthologous Mutant
permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public...acetylcholinesterase. Bull Entomol Res 2005, 95:371–380. 24. Hassan MM, Widaa SO, Osman OM, Numiary MSM, Ibrahim MA, Abushama HM: Insecticide resistance in the
Spatial and Temporal Potato Intensification Drives Insecticide Resistance in the Specialist Herbivore, Leptinotarsa decemlineata.
Huseth, Anders S; Petersen, Jessica D; Poveda, Katja; Szendrei, Zsofia; Nault, Brian A; Kennedy, George G; Groves, Russell L
Landscape-scale intensification of individual crops and pesticide use that is associated with this intensification is an emerging, environmental problem that is expected to have unequal effects on pests with different lifecycles, host ranges, and dispersal abilities. We investigate if intensification of a single crop in an agroecosystem has a direct effect on insecticide resistance in a specialist insect herbivore. Using a major potato pest, Leptinotarsa decemlineata, we measured imidacloprid (neonicotinoid) resistance in populations across a spatiotemporal crop production gradient where potato production has increased in Michigan and Wisconsin, USA. We found that concurrent estimates of area and temporal frequency of potato production better described patterns of imidacloprid resistance among L. decemlineata populations than general measures of agricultural production (% cropland, landscape diversity). This study defines the effects individual crop rotation patterns can have on specialist herbivore insecticide resistance in an agroecosystem context, and how impacts of intensive production can be estimated with general estimates of insecticide use. Our results provide empirical evidence that variation in the intensity of neonicotinoid-treated potato in an agricultural landscape can have unequal impacts on L. decemlineata insecticide insensitivity, a process that can lead to resistance and locally intensive insecticide use. Our study provides a novel approach applicable in other agricultural systems to estimate impacts of crop rotation, increased pesticide dependence, insecticide resistance, and external costs of pest management practices on ecosystem health.
Spatial and Temporal Potato Intensification Drives Insecticide Resistance in the Specialist Herbivore, Leptinotarsa decemlineata.
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Anders S Huseth
Full Text Available Landscape-scale intensification of individual crops and pesticide use that is associated with this intensification is an emerging, environmental problem that is expected to have unequal effects on pests with different lifecycles, host ranges, and dispersal abilities. We investigate if intensification of a single crop in an agroecosystem has a direct effect on insecticide resistance in a specialist insect herbivore. Using a major potato pest, Leptinotarsa decemlineata, we measured imidacloprid (neonicotinoid resistance in populations across a spatiotemporal crop production gradient where potato production has increased in Michigan and Wisconsin, USA. We found that concurrent estimates of area and temporal frequency of potato production better described patterns of imidacloprid resistance among L. decemlineata populations than general measures of agricultural production (% cropland, landscape diversity. This study defines the effects individual crop rotation patterns can have on specialist herbivore insecticide resistance in an agroecosystem context, and how impacts of intensive production can be estimated with general estimates of insecticide use. Our results provide empirical evidence that variation in the intensity of neonicotinoid-treated potato in an agricultural landscape can have unequal impacts on L. decemlineata insecticide insensitivity, a process that can lead to resistance and locally intensive insecticide use. Our study provides a novel approach applicable in other agricultural systems to estimate impacts of crop rotation, increased pesticide dependence, insecticide resistance, and external costs of pest management practices on ecosystem health.
Insecticide resistance and nutrition interactively shape life-history parameters in German cockroaches
Jensen, Kim; Ko, Alexander E.; Schal, Coby; Silverman, Jules
Fitness-related costs of evolving insecticide resistance have been reported in a number of insect species, but the interplay between evolutionary adaptation to insecticide pressure and variable environmental conditions has received little attention. We provisioned nymphs from three German cockroach (Blattella germanica L.) populations, which differed in insecticide resistance, with either nutritionally rich or poor (diluted) diet throughout their development. One population was an insecticide-susceptible laboratory strain; the other two populations originated from a field-collected indoxacarb-resistant population, which upon collection was maintained either with or without further selection with indoxacarb. We then measured development time, survival to the adult stage, adult body size, and results of a challenge with indoxacarb. Our results show that indoxacarb resistance and poor nutritional condition increased development time and lowered adult body size, with reinforcing interactions. We also found lower survival to the adult stage in the indoxacarb-selected population, which was exacerbated by poor nutrition. In addition, nutrition imparted a highly significant effect on indoxacarb susceptibility. This study exemplifies how poor nutritional condition can aggravate the life-history costs of resistance and elevate the detrimental effects of insecticide exposure, demonstrating how environmental conditions and resistance may interactively impact individual fitness and insecticide efficacy.
Behavioral Avoidance - Will Physiological Insecticide Resistance Level of Insect Strains Affect Their Oviposition and Movement Responses?
Nansen, Christian; Baissac, Olivier; Nansen, Maria; Powis, Kevin; Baker, Greg
Agricultural organisms, such as insect herbivores, provide unique opportunities for studies of adaptive evolutionary processes, including effects of insecticides on movement and oviposition behavior. In this study, Brassica leaves were treated with one of two non-systemic insecticides and exposed to two individual strains (referred to as single or double resistance) of diamondback moth (Plutella xylostella) (DBM) exhibiting physiological resistance. Behavioral responses by these two strains were compared as part of characterizing the relative effect of levels of physiological resistance on the likelihood of insects showing signs of behavioral avoidance. For each DBM strain, we used choice bioassays to quantify two possible types of behavioral avoidance: 1) females ovipositing predominantly on leaf surfaces without insecticides, and 2) larvae avoiding insecticide-treated leaf surfaces. In three-choice bioassays (leaves with no pesticide, 50% coverage with pesticide, or 100% coverage with pesticide), females from the single resistance DBM strain laid significantly more eggs on water treated leaves compared to leaves with 100% insecticide coverage (both gamma-cyhalothrin and spinetoram). Females from the double resistance DBM strain also laid significantly more eggs on water treated leaves compared to leaves with 100% gamma-cyhalothrin, while moths did not adjust their oviposition behavior in response to spinetoram. Larvae from the single resistance DBM strain showed a significant increase in mobility in response to both insecticides and avoided insecticide-treated portions of leaves when given a choice. On the other hand, DBM larvae from the double resistance strain showed a significant decrease in mobility in response to insecticides, and they did not avoid insecticide-treated portions of leaves when given a choice. Our results suggest that pest populations with physiological resistance may show behavioral avoidance, as resistant females avoided oviposition on
Does Drought Increase the Risk of Insects Developing Behavioral Resistance to Systemic Insecticides?
Khodaverdi, Haleh; Fowles, Trevor; Bick, Emily; Nansen, Christian
Increases in severity and frequency of drought periods, average global temperatures, and more erratic fluctuations in rainfall patterns due to climate change are predicted to have a dramatic impact on agricultural production systems. Insect pest populations in agricultural and horticultural systems are also expected to be impacted, both in terms of their spatial and temporal distributions and in their status as pest species. In this opinion-based article, we discuss how indirect effects of drought may adversely affect the performance of systemic insecticides and also lead to increased risk of insect pests developing behavioral insecticide resistance. We hypothesize that more pronounced drought will decrease uptake and increase the magnitude of nonuniform translocation of systemic insecticides within treated crop plants, and that may have two concurrent consequences: 1) reduced pesticide performance, and 2) increased likelihood of insect pests evolving behavioral insecticide resistance. Under this scenario, pests that can sense and avoid acquisition of lethal dosages of systemic insecticides within crop plants will have a selective advantage. This may lead to selection for insect behavioral avoidance, so that insects predominantly feed and oviposit on portions of crop plants with low concentration of systemic insecticide. Limited research has been published on the effect of environmental variables, including drought, on pesticide performance, but we present and discuss studies that support the hypothesis described above. In addition, we wish to highlight the importance of studying the many ways environmental factors can affect, directly and indirectly, both the performance of insecticides and the risk of target insect pests developing resistance.
Monitoring of Insecticide Resistance and Genetic Analysis of Triazophos Resistance in Chilo suppressalis (Lepidoptera:Pyralidae)
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LIU Ze-wen; CAO Ming-zhang; HAN Zhao-jun; SHEN Jin-liang; ZHANG Ling-chun; ZHANG Jin-zhen; LU Mei; LIU Xiao-yu; ZHOU Wei-jun
During 2001 and 2002, insecticide resistance in the fourth instar larvae of striped stem borer (Chilo suppressalis), which were collected from Zhejiang, Jiangsu, Anhui and Jiangxi provinces in China, was monitored using topical application method. Low level of resistance to fipronil (6.5-fold) was detected for the first time in RA (Rui'an) population from southeast Zhejiang, but the other six populations tested remained susceptible to this recently introduced insecticide. No resistance to abamectin had been found after examining six populations from Zhejiang, Jiangsu and Anhui provinces. Resistance to triazophos was monitored in ten populations from the four Provinces, and very high level resistance(163.1-fold) was found in RA population, moderate (18.2-fold) in WZ (Wenzhou, Zhejiang Province) population, and low (6.7- to 9.7-fold) in populations of CS (Changshu), XS (Xishan) and JT (Jintan) from south Jiangsu, whereas the other five populations were susceptible. All the nine populations monitored were resistant to monosultap with varying degree, i.e. high level (113.7- and 57.6-fold, respectively) of resistance in RA and YF (Yifeng, Jiangxi Province) populations, moderate (11.0- to 29.7-fold) in WZ, CS, JT and TH (Taihu, Anhui Province) populations, low (6.7- and 7.5-fold, respectively) in XY (Xinyang, Jiangsu Province) and XS populations, and the lowest (3.7-fold) in GY (Guanyun, Jiangsu Province) population. Inheritance of resistance in triazophos selected strain Rts was studied through reciprocal cross and backcross experiments. The preliminary results indicated that inheritance of triazophos resistance in Rts strain was incompletely dominant, with degrees of dominance being 0.46 and 0.68 for reciprocal crosses, and that the resistance was controlled by a major gene, though minor modifying gene(s) might be involved.
Detoxification enzymes associated with insecticide resistance in laboratory strains of Anopheles arabiensis of different geographic origin
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Nardini Luisa
Full Text Available Abstract Background The use of insecticides to control malaria vectors is essential to reduce the prevalence of malaria and as a result, the development of insecticide resistance in vector populations is of major concern. Anopheles arabiensis is one of the main African malaria vectors and insecticide resistance in this species has been reported in a number of countries. The aim of this study was to investigate the detoxification enzymes that are involved in An. arabiensis resistance to DDT and pyrethroids. Methods The detoxification enzyme profiles were compared between two DDT selected, insecticide resistant strains of An. arabiensis, one from South Africa and one from Sudan, using the An. gambiae detoxification chip, a boutique microarray based on the major classes of enzymes associated with metabolism and detoxification of insecticides. Synergist assays were performed in order to clarify the roles of over-transcribed detoxification genes in the observed resistance phenotypes. In addition, the presence of kdr mutations in the colonies under investigation was determined. Results The microarray data identifies several genes over-transcribed in the insecticide selected South African strain, while in the Sudanese population, only one gene, CYP9L1, was found to be over-transcribed. The outcome of the synergist experiments indicate that the over-transcription of detoxification enzymes is linked to deltamethrin resistance, while DDT and permethrin resistance are mainly associated with the presence of the L1014F kdr mutation. Conclusions These data emphasise the complexity associated with resistance phenotypes and suggest that specific insecticide resistance mechanisms cannot be extrapolated to different vector populations of the same species.
Correlation between carboxylesterase alleles and insecticide resistance in Culex pipiens complex from China
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Liu Yangyang
Full Text Available Abstract Background In China, large amounts of chemical insecticides are applied in fields or indoors every year, directly or indirectly bringing selection pressure on vector mosquitoes. Culex pipiens complex has evolved to be resistant to all types of chemical insecticides, especially organophosphates, through carboxylesterases. Six resistant carboxylesterase alleles (Ester were recorded previously and sometimes co-existed in one field population, representing a complex situation for the evolution of Ester genes. Results In order to explore the evolutionary scenario, we analyzed the data from an historical record in 2003 and a recent investigation on five Culex pipiens pallens populations sampled from north China in 2010. Insecticide bioassays showed that these five populations had high resistance to pyrethroids, medium resistance to organophosphates, and low resistance to carbamates. Six types of Ester alleles, EsterB1, Ester2, Ester8, Ester9, EsterB10, and Ester11 were identified, and the overall pattern of their frequencies in geographic distribution was consistent with the report seven years prior to this study. Statistical correlation analysis indicated that Ester8 and Ester9 positively correlated with resistance to four insecticides, and EsterB10 to one insecticide. The occurrences of these three alleles were positively correlated, while the occurrence of EsterB1 was negatively correlated with Ester8, indicating an allelic competition. Conclusion Our analysis suggests that one insecticide can select multiple Ester alleles and one Ester allele can work on multiple insecticides. The evolutionary scenario of carboxylesterases under insecticide selection is possibly "one to many".
Insensitive Acetylcholine Receptor Conferring Resistance of Plutella xylostella to Nereistoxin Insecticides
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CHENG Luo-gen; YU Guang; CHEN Zi-hao; LI Zhong-yin
The combinative rate measurement of (3-[Ⅰ125] iodotyrosyl) α-bungarotoxin was applied in the analysis of the relation between nerve acetylcholine receptor and three types of insecticide resistance in diamondback moth, Plutella xylostella (L.). In the dimehypo-resistant strain and in the cartap-resistant strain, the nerve acetylcholine receptor showed the remarkable insensitivity to dimehypo and cartap, of which the binding rate to ligand was approximately 66 and 60%, respectively, of the susceptible strain. The sensitivity to deltamethrin in the deltamethrin-resistant strain did not show visible change. These results indicated that the decline in the sensitivity of nerve acetylcholine receptor to insecticide might be a potential mechanism to nereistoxin insecticides resistance in the diamondback moth.
Insecticide resistance and, efficacy of space spraying and larviciding in the control of dengue vectors Aedes aegypti and Aedes albopictus in Sri Lanka.
Karunaratne, S H P P; Weeraratne, T C; Perera, M D B; Surendran, S N
Unprecedented incidence of dengue has been recorded in Sri Lanka in recent times. Source reduction and use of insecticides in space spraying/fogging and larviciding, are the primary means of controlling the vector mosquitoes Aedes aegypti and Ae. albopictus in the island nation. A study was carried out to understand insecticide cross-resistance spectra and mechanisms of insecticide resistance of both these vectors from six administrative districts, i.e. Kandy, Kurunegala, Puttalam, Gampaha, Ratnapura and Jaffna, of Sri Lanka. Efficacy of the recommended dosages of frequently used insecticides in space spraying and larviciding in dengue vector control programmes was also tested. Insecticide bioassay results revealed that, in general, both mosquito species were highly resistant to DDT but susceptible to propoxur and malathion except Jaffna Ae. aegypti population. Moderate resistance to malathion shown by Jaffna Ae. aegypti population correlated with esterase and malathion carboxylesterase activities of the population. High levels of acetylcholinesterase (AChE) insensitivity in the absence of malathion and propoxur resistance may be due to non-synaptic forms of AChE proteins. Moderate pyrethroid resistance in the absence of high monooxygenase levels indicated the possible involvement of 'kdr' type resistance mechanism in Sri Lankan dengue vectors. Results of the space spraying experiments revealed that 100% mortality at a 10 m distance and >50% mortality at a 50 m distance can be achieved with malathion, pesguard and deltacide even in a ground with dense vegetation. Pesguard and deltacide spraying gave 100% mortality up to 50 m distance in open area and areas with little vegetation. Both species gave >50% mortalities for deltacide at a distance of 75 m in a dense vegetation area. Larval bioassays conducted in the laboratory showed that a 1 ppm temephos solution can maintain a larval mortality rate of 100% for ten months, and the mortality rate declined to 0% in the
Three years of insecticide resistance monitoring in Anopheles gambiae in Burkina Faso: resistance on the rise?
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Badolo Athanase
Full Text Available Abstract Background and methods A longitudinal Anopheles gambiae s.l. insecticide-resistance monitoring programme was established in four sentinel sites in Burkina Faso. For three years, between 2008 and 2010, WHO diagnostic dose assays were used to measure the prevalence of resistance to all the major classes of insecticides at the beginning and end of the malaria transmission season. Species identification and genotyping for target site mutations was also performed and the sporozoite rate in adults determined. Results At the onset of the study, resistance to DDT and pyrethroids was already prevalent in An. gambiae s.l. from the south-west of the country but mosquitoes from the two sites in central Burkina Faso were largely susceptible. Within three years, DDT and permethrin resistance was established in all four sites. Carbamate and organophosphate resistance remains relatively rare and largely confined to the south-western areas although a small number of bendiocarb survivors were found in all sites by the final round of monitoring. The ace-1R target site resistance allele was present in all localities and its frequency exceeded 20% in 2010 in two of the sites. The frequency of the 1014F kdr mutation increased throughout the three years and by 2010, the frequency of 1014F in all sites combined was 0.02 in Anopheles arabiensis, 0.56 in An. gambiae M form and 0.96 in An. gambiae S form. This frequency did not differ significantly between the sites. The 1014S kdr allele was only found in An. arabiensis but its frequency increased significantly throughout the study (P = 0.0003 and in 2010 the 1014S allele frequency was 0.08 in An. arabiensis. Maximum sporozoite rates (12% were observed in Soumousso in 2009 and the difference between sites is significant for each year. Conclusion Pyrethroid and DDT resistance is now established in An. gambiae s.l. throughout Burkina Faso. Results from diagnostic dose assays are highly variable within and
Biochemical mechanisms of insecticide resistance in field population of Dengue vector Aedes aegypti (Diptera: Culicidae.
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R. Muthusamy
Full Text Available Insecticide resistance has been known to be prevalent in several insect species including mosquito. It has become a major problem in vector control programme due to pesticide resistance through detoxification enzymes. The present study investigated the toxicity of Ae. aegypti to organophosphates and pyrethroid insecticide and biochemical mechanisms involved in insecticide resistance in larval population. Larval bioassay revealed an LC50 value of 0.734 ppm for dichlorvos and 1.140 ppm for λ-cyhalothrin exposure. Biochemical assay revealed increased activity of AChE (0.3 µmole/mg protein and GST in dichlorvos (1-1.5 µmole/mg protein treatment and esterase activity in λ-cyhalothrin treated compared to control activity. These studies suggest that AChE and GST is associated with organophosphate and esterase associated with pyrethroid resistance in Ae. aegypti.
Insecticide resistance and activities of relative enzymes in different populations of the white backed planthopper
Institute of Scientific and Technical Information of China (English)
@@ White backed planthopper (WBPH), Sogatella furcifera (Horvath), is one of the most devastating insect pests on rice in Asia. Its control mainly depended on the chemical pesticides. Surveys of insecticide susceptibility revealed that organophosphorus and carbamate resistance has emerged since early 1980s in China and Japan. WBPH has the long distance migration property, and Heinrichs(1994) considered that the migration might influence the resistance level of planthoppers. So we conducted the comparative studies on insecticide susceptibility and activities of resistance relative enzymes in four WBPH populations collected from Zhejiang, Yunnan, and Hainan provinces of China in 1997.
Functional characterization of glutathione S-transferases associated with insecticide resistance in Tetranychus urticae
Pavlidi, N.; Tseliou, V.; Riga, M.; Nauen, R.; Van Leeuwen, T.; Labrou, N.E.; Vontas, J.
The two-spotted spider mite Tetranychus urticae is one of the most important agricultural pests world-wide. It is extremely polyphagous and develops resistance to acaricides. The overexpression of several glutathione S-transferases (GSTs) has been associated with insecticide resistance. Here, we fun
Identifying genomic changes associated with insecticide resistance in the dengue mosquito Aedes aegypti by deep targeted sequencing.
Faucon, Frederic; Dusfour, Isabelle; Gaude, Thierry; Navratil, Vincent; Boyer, Frederic; Chandre, Fabrice; Sirisopa, Patcharawan; Thanispong, Kanutcharee; Juntarajumnong, Waraporn; Poupardin, Rodolphe; Chareonviriyaphap, Theeraphap; Girod, Romain; Corbel, Vincent; Reynaud, Stephane; David, Jean-Philippe
The capacity of mosquitoes to resist insecticides threatens the control of diseases such as dengue and malaria. Until alternative control tools are implemented, characterizing resistance mechanisms is crucial for managing resistance in natural populations. Insecticide biodegradation by detoxification enzymes is a common resistance mechanism; however, the genomic changes underlying this mechanism have rarely been identified, precluding individual resistance genotyping. In particular, the role of copy number variations (CNVs) and polymorphisms of detoxification enzymes have never been investigated at the genome level, although they can represent robust markers of metabolic resistance. In this context, we combined target enrichment with high-throughput sequencing for conducting the first comprehensive screening of gene amplifications and polymorphisms associated with insecticide resistance in mosquitoes. More than 760 candidate genes were captured and deep sequenced in several populations of the dengue mosquito Ae. aegypti displaying distinct genetic backgrounds and contrasted resistance levels to the insecticide deltamethrin. CNV analysis identified 41 gene amplifications associated with resistance, most affecting cytochrome P450s overtranscribed in resistant populations. Polymorphism analysis detected more than 30,000 variants and strong selection footprints in specific genomic regions. Combining Bayesian and allele frequency filtering approaches identified 55 nonsynonymous variants strongly associated with resistance. Both CNVs and polymorphisms were conserved within regions but differed across continents, confirming that genomic changes underlying metabolic resistance to insecticides are not universal. By identifying novel DNA markers of insecticide resistance, this study opens the way for tracking down metabolic changes developed by mosquitoes to resist insecticides within and among populations.
Dynamics of multiple insecticide resistance in the malaria vector Anopheles gambiae in a rice growing area in South-Western Burkina Faso
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Ouédraogo Jean-Bosco
Full Text Available Abstract Background Insecticide resistance of the main malaria vector, Anopheles gambiae, has been reported in south-western Burkina Faso, West Africa. Cross-resistance to DDT and pyrethroids was conferred by alterations at site of action in the sodium channel, the Leu-Phe kdr mutation; resistance to organophosphates and carbamates resulted from a single point mutation in the oxyanion hole of the acetylcholinesterase enzyme designed as ace-1R. Methods An entomological survey was carried out during the rainy season of 2005 at Vallée du Kou, a rice growing area in south-western Burkina Faso. At the Vallée du Kou, both insecticide resistance mechanisms have been previously described in the M and S molecular forms of An. gambiae. This survey aimed i to update the temporal dynamics and the circumsporozoite infection rate of the two molecular forms M and S of An. gambiae ii to update the frequency of the Leu-Phe kdr mutation within these forms and finally iii to investigate the occurrence of the ace-1R mutation. Mosquitoes collected by indoor residual collection and by human landing catches were counted and morphologically identified. Species and molecular forms of An. gambiae, ace-1R and Leu-Phe kdr mutations were determined using PCR techniques. The presence of the circumsporozoite protein of Plasmodium falciparum was determined using ELISA. Results Anopheles gambiae populations were dominated by the M form. However the S form occurred in relative important proportion towards the end of the rainy season with a maximum peak in October at 51%. Sporozoite rates were similar in both forms. The frequency of the Leu-Phe kdr mutation in the S form reached a fixation level while it is still spreading in the M form. Furthermore, the ace-1R mutation prevailed predominately in the S form and has just started spreading in the M form. The two mutations occurred concomitantly both in M and S populations. Conclusion These results showed that the Vallée du Kou
Modes of action, resistance and toxicity of insecticides targeting nicotinic acetylcholine receptors.
Ihara, Makoto; Buckingham, Steven D; Matsuda, Kazuhiko; Sattelle, David B
Nicotinic acetylcholine receptors (nAChRs) are members of the cys-loop superfamily of ligand-gated ion channels (cys-loop LGICs) and mediate fast cholinergic synaptic transmission in the nervous system of insects. The completion of many insect genome projects has greatly enhanced our understanding of the individual subunits that make up nAChR gene families from an insect genetic model organism (Drosophila melanogaster), crop pests, disease vectors and beneficial (pollinator) species. In addition to considerable insect nAChR subunit diversity, individual subunits can be subject to alternative splicing and RNA editing and these post-transcriptional modifications can add significantly to the diversity of nAChR receptor subtypes. The actions of insecticides targeting nAChRs, notably cartap, neonicotinoids, sulfoximines, flupyradifurone, spinosyns and triflumezopyrim are reviewed. Structural studies obtained using an acetylcholine binding protein (AChBP) co-crystallised with neonicotinoids have yielded important new insights into the requirements for neonicotinoid insecticide - nAChR interactions. The persistent application of insecticides to crop pests leads to the onset of resistance and several examples of resistance to insecticides targeting nAChRs have been documented. Understanding the molecular basis of resistance can inform our understanding of the mechanism of insecticide action. It also provides an important driver for the development of new chemistry, diagnostic tests for resistance and the adoption of application strategies designed to attenuate such problems. Finally, we consider toxicity issues relating to nAChR-active insecticides, with particular reference to beneficial insect species (pollinators) as well as mammalian and avian toxicity. This review is part of the special issue "Insecticide Mode of Action: From Insect to Mammalian Toxicity.".
Dissecting the organ specificity of insecticide resistance candidate genes in Anopheles gambiae: known and novel candidate genes
Background The elevated expression of enzymes with insecticide metabolism activity can lead to high levels of insecticide resistance in the malaria vector, Anopheles gambiae. In this study, adult female mosquitoes from an insecticide susceptible and resistant strain were dissected into four different body parts. RNA from each of these samples was used in microarray analysis to determine the enrichment patterns of the key detoxification gene families within the mosquito and to identify additio...
Vectorial status and insecticide resistance of Anopheles funestus from a sugar estate in southern Mozambique
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Nhamahanga Eduardo
Full Text Available Abstract Background The dual problems of rising insecticide resistance in the malaria vectors and increasing human malaria cases since 2001 in southern Mozambique are cause for serious concern. The selection of insecticides for use in indoor residual spraying (IRS programmes is highly dependent on the extent to which local mosquitoes are susceptible to the approved classes of insecticides. The insecticide resistance status and role in malaria transmission of Anopheles funestus was evaluated at the Maragra Sugar Estate in southern Mozambique where an IRS vector control programme has been in operation for seven years using the carbamate insecticide bendiocarb. Results No Anopheles species were captured inside the sugar estate control area. Anopheles funestus group captured outside of the estate represented 90% (n = 475 of the total collections. Of the specimens identified to species by PCR (n = 167, 95% were An. funestus s.s. One An. rivulorum was identified and seven specimens did not amplify. The Anopheles gambiae complex was less abundant (n = 53 and of those identified (n = 33 76% were An. arabiensis and 24% An. merus. Insecticide susceptibility tests showed that wild-caught and F-1 family An. funestus were resistant to deltamethrin (32.5% mortality and lambda-cyhalothrin (14.6% mortality, less so to bendiocarb (71.5% mortality and fully susceptible to both malathion and DDT (100%. Bendiocarb and pyrethroid resistance was nullified using 4% piperonyl butoxide (Pbo, strongly suggesting that both are mediated by P450 monooxygenase detoxification. ELISA tests of An. funestus for Plasmodium falciparum, gave a sporozoite rate of 6.02% (n = 166. One unidentified member of the An. gambiae complex tested positive for P. falciparum sporozoites. Conclusion Anopheles funestus was found to be the most abundant and principle vector of malaria in this area, with members of the An. gambiae complex being secondary vectors. Despite the continual use of
Insecticide resistance in Blattella germanica (L.)(Dictyoptera: Blattellidae) from food producing establishments in Denmark
DEFF Research Database (Denmark)
Jensen, Karl-Martin Vagn
Abstract-A number of cases of Blartella germanica control failure were reported to the Danish Pest Infestation Laboratory from 1987 to 1991. A screening of the insecticide resistance in B. germancia in some selected locations was conducted with permethrin using tarsal contact tests to estimate KT......,(/WHO/VBC/75.593). Based on these data more detailed measurement of the resistance in the German Cockroaches from chosen locations was then assessed by topical application techniques; 2.5 p1 insecticide in acetone on the ventral ...
Evolution of Resistance by Helicoverpa zea (Lepidoptera: Noctuidae) Infesting Insecticidal Crops in the Southern United States.
Pan, Zaiqi; Onstad, David; Crain, Philip; Crespo, Andre; Hutchison, William; Buntin, David; Porter, Pat; Catchot, Angus; Cook, Don; Pilcher, Clint; Flexner, Lindsey; Higgins, Laura
We created a deterministic, frequency-based model of the evolution of resistance by corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), to insecticidal traits expressed in crops planted in the heterogeneous landscapes of the southern United States. The model accounts for four generations of selection by insecticidal traits each year. We used the model results to investigate the influence of three factors on insect resistance management (IRM): 1) how does adding a third insecticidal trait to both corn and cotton affect durability of the products, 2) how does unstructured corn refuge influence IRM, and 3) how do block refuges (50% compliance) and blended refuges compare with regard to IRM? When Bt cotton expresses the same number of insecticidal traits, Bt corn with three insecticidal traits provides longer durability than Bt corn with two pyramided traits. Blended refuge provides similar durability for corn products compared with the same level of required block refuge when the rate of refuge compliance by farmers is 50%. Results for Mississippi and Texas are similar, but durabilities for corn traits are surprisingly lower in Georgia, where unstructured corn refuge is the highest of the three states, but refuge for Bt cotton is the lowest of the three states. Thus, unstructured corn refuge can be valuable for IRM but its influence is determined by selection for resistance by Bt cotton.
Chlorfenapyr: a new insecticide with novel mode of action can control pyrethroid resistant malaria vectors
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Srivastava Harish C
Full Text Available Abstract Background Malaria vectors have acquired widespread resistance to many of the currently used insecticides, including synthetic pyrethroids. Hence, there is an urgent need to develop alternative insecticides for effective management of insecticide resistance in malaria vectors. In the present study, chlorfenapyr was evaluated against Anopheles culicifacies and Anopheles stephensi for its possible use in vector control. Methods Efficacy of chlorfenapyr against An. culicifacies and An. stephensi was assessed using adult bioassay tests. In the laboratory, determination of diagnostic dose, assessment of residual activity on different substrates, cross-resistance pattern with different insecticides and potentiation studies using piperonyl butoxide were undertaken by following standard procedures. Potential cross-resistance patterns were assessed on field populations of An. culicifacies. Results A dose of 5.0% chlorfenapyr was determined as the diagnostic concentration for assessing susceptibility applying the WHO tube test method in anopheline mosquitoes with 2 h exposure and 48 h holding period. The DDT-resistant/malathion-deltamethrin-susceptible strain of An. culicifacies species C showed higher LD50 and LD99 (0.67 and 2.39% respectively values than the DDT-malathion-deltamethrin susceptible An. culicifacies species A (0.41 and 2.0% respectively and An. stephensi strains (0.43 and 2.13% respectively and there was no statistically significant difference in mortalities among the three mosquito species tested (p > 0.05. Residual activity of chlorfenapyr a.i. of 400 mg/m2 on five fabricated substrates, namely wood, mud, mud+lime, cement and cement + distemper was found to be effective up to 24 weeks against An. culicifacies and up to 34 weeks against An. stephensi. No cross-resistance to DDT, malathion, bendiocarb and deltamethrin was observed with chlorfenapyr in laboratory-reared strains of An. stephensi and field-caught An. culicifacies
Mixed function oxidases and insecticide resistance in medically important insects
MFOs are a large diverse superfamily of enzymes found in all insect tissues. They are involved in the metabolism of xenobiotics (e.g. drugs, pesticides and plant toxins) and endogenous compounds (e.g. ecdysteroids and juvenile hormones). They are also involved in bioactivation of phosphorothioate compounds such as organophosphorus insecticides. They have very diverse activities like hydroxylation, epoxidation, N-, O-or S-dealkylation, deamination, sulfoxidation, desulfuration and oxidative de...
A Common Mechanism for Resistance to Oxime Reactivation of Acetylcholinesterase Inhibited by Organophosphorus Compounds
Organophosphates and Carbamates, Butterworth & Heinemann, Oxford, 1992. pp. 555–577. [2] P. Taylor, Anticholinesterase agents, in: L.L. Brunton, J.S...agent poisoning by in vitro analysis, Toxicol. Appl. Pharmacol. 219 (2007) 226–234. [7] A. Ashani, Z. Radic, I. Tsigelny, D.C. Vellom, N.A. Pickering... organophosphate -inhibited fetal bovine serum acetylcholinesterase by monoquaternary and bisquaternary ligands, Mol. Pharmacol. 55 (1998) 718– 726. [19] Z. Kovarik
Insecticide Resistance in Eggs and First Instars of the Bed Bug, Cimex lectularius (Hemiptera: Cimicidae).
Campbell, Brittany E; Miller, Dini M
Two strains of the common bed bug, Cimex lectularius L., eggs and first instars collected from pyrethroid-resistant adults were evaluated for insecticide resistance and compared to a susceptible strain. Dose-response bioassays were conducted using two insecticide formulations (Temprid: imidacloprid/β-cyfluthrin, and Transport: acetamiprid/ bifenthrin). The lethal concentration (LC50) for the two resistant egg strains exposed to imidacloprid/β-cyfluthrin ranged from 3 to 5-fold higher than susceptible strain eggs. Resistant strain eggs dipped into formulations of acetamiprid/bifenthrin had LC50 values which were significantly greater (39 to 1,080-fold) than susceptible strain eggs. Similar to eggs, resistant strain first instars exposed to residual applications of imidacloprid/β-cyfluthrin had LC50 values ranging from 121 to 493-fold greater than susceptible strain first instars. When resistant strain first instars were treated with acetamiprid/bifenthrin, they had LC50 values that were 99 to >1,900-fold greater than susceptible strain first instars. To determine differences between egg and first instar resistance, stage resistance ratios (SRR) were compared between the two stages. There was little difference between the egg and first instar stages, indicated by small SRR values ranging from 1.1 to 10.0. This study suggests that insecticide resistance is expressed early during bed bug development.
Insecticide Resistance in Eggs and First Instars of the Bed Bug, Cimex lectularius (Hemiptera: Cimicidae
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Brittany E. Campbell
Full Text Available Two strains of the common bed bug, Cimex lectularius L., eggs and first instars collected from pyrethroid-resistant adults were evaluated for insecticide resistance and compared to a susceptible strain. Dose-response bioassays were conducted using two insecticide formulations (Temprid: imidacloprid/β-cyfluthrin, and Transport: acetamiprid/ bifenthrin. The lethal concentration (LC50 for the two resistant egg strains exposed to imidacloprid/β-cyfluthrin ranged from 3 to 5-fold higher than susceptible strain eggs. Resistant strain eggs dipped into formulations of acetamiprid/bifenthrin had LC50 values which were significantly greater (39 to 1,080-fold than susceptible strain eggs. Similar to eggs, resistant strain first instars exposed to residual applications of imidacloprid/β-cyfluthrin had LC50 values ranging from 121 to 493-fold greater than susceptible strain first instars. When resistant strain first instars were treated with acetamiprid/bifenthrin, they had LC50 values that were 99 to >1,900-fold greater than susceptible strain first instars. To determine differences between egg and first instar resistance, stage resistance ratios (SRR were compared between the two stages. There was little difference between the egg and first instar stages, indicated by small SRR values ranging from 1.1 to 10.0. This study suggests that insecticide resistance is expressed early during bed bug development.
Sulfoxaflor and the sulfoximine insecticides: chemistry, mode of action and basis for efficacy on resistant insects.
Sparks, Thomas C; Watson, Gerald B; Loso, Michael R; Geng, Chaoxian; Babcock, Jon M; Thomas, James D
The sulfoximines, as exemplified by sulfoxaflor ([N-[methyloxido[1-[6-(trifluoromethyl)-3-pyridinyl]ethyl]-λ(4)-sulfanylidene] cyanamide] represent a new class of insecticides. Sulfoxaflor exhibits a high degree of efficacy against a wide range of sap-feeding insects, including those resistant to neonicotinoids and other insecticides. Sulfoxaflor is an agonist at insect nicotinic acetylcholine receptors (nAChRs) and functions in a manner distinct from other insecticides acting at nAChRs. The sulfoximines also exhibit structure activity relationships (SAR) that are different from other nAChR agonists such as the neonicotinoids. This review summarizes the sulfoximine SAR, mode of action and the biochemistry underlying the observed efficacy on resistant insect pests, with a particular focus on sulfoxaflor.
Susceptibility of Bonagota salubricola (Lepidoptera: Tortricidae) to Insecticides in Brazilian Apple Orchards: Implications for Resistance Management.
Bernardi, Daniel; Botton, Marcos; Andreazza, Felipe; Arnaldo Batista Neto E Silva, Oscar; João Arioli, Cristiano; Omoto, Celso
The Bonagota salubricola (Meyrick) is a major pest in apple orchards in Brazil, and chemical control has been the primary tool for insect management. To support the development of an insect resistance management (IRM) program, baseline studies of the susceptibility of a reference (laboratory) B. salubricola population were conducted; seven wild B. salubricola populations were monitored for susceptibility to insecticide; and the toxicity of some new chemicals to third-instar larvae and adults was evaluated by a leaf dip and ingestion bioassay, respectively. Neonates from the susceptible (laboratory) population exposed to insecticide showed an LC50 ranging from 0.34 (spinetoram) to 30.19 (novaluron) µg of a.i. ml(-1) (88.8-fold variation), so the diagnostic concentrations for an IRM program in Brazil based on the LC99 were as follows: 19.0 µg of a.i./ml chlorantraniliprole, 510.0 novaluron, 72.0 phosmet, 4.1 spinetoram, 12.8 spinosad, and 110.0 tebufenozide. Based on the LC99, significant differences were not observed in the susceptibility of the field and laboratory populations to chlorantraniliprole, phosmet, spinetoram, spinosad, and tebufenozide insecticides, but there were significant differences in the survival rates of the two populations to novaluron insecticide (3.3%). All insecticides at the diagnostic concentrations showed high toxicity to third-instar larvae (mortality rates between 73 to 97%). Phosmet, spinetoram, and spinosad insecticides were toxic to B. salubricola adults (mortality >85%), while chlorantraniliprole, novaluron, and tebufenozide insecticides caused mortality below 5%. The evaluated insecticides showed high toxicity to different developmental stages of B. salubricola, so the diagnostic concentrations may be used in IRM programs in Brazil.
Identification of genes involved in pyrethroid-, propoxur-, and dichlorvos- insecticides resistance in the mosquitoes, Culex pipiens complex (Diptera: Culicidae).
Li, Chun-xiao; Guo, Xiao-xia; Zhang, Ying-mei; Dong, Yan-de; Xing, Dan; Yan, Ting; Wang, Gang; Zhang, Heng-duan; Zhao, Tong-yan
Culex pipiens pallens and Cx. p. quinquefasciatus are important vectors of many diseases, such as West Nile fever and lymphatic filariasis. The widespread use of insecticides to control these disease vectors and other insect pests has led to insecticide resistance becoming common in these species. In this study, high throughout Illumina sequencing was used to identify hundreds of Cx. p. pallens and Cx. p. quinquefasciatus genes that were differentially expressed in response to insecticide exposure. The identification of these genes is a vital first step for more detailed investigation of the molecular mechanisms involved in insecticide resistance in Culex mosquitoes.
INSECTICIDE RESISTANCE IN THE GROUND SPIDER, Pardosa sumatrana (THORELL, 1890; ARANEAE: LYCOSIDAE).
Tahir, Hafiz Muhammad; Khizar, Farva; Naseem, Sajida; Yaqoob, Rabia; Samiullah, Khizar
Elevated levels of insecticides detoxifying enzymes, such as esterases, glutathione S-transferases (GSTs), and cytochrome P-450 monooxygenases, act in the resistance mechanisms in insects. In the present study, levels of these enzymes in the insecticide-resistant ground spider Pardosa sumatrana (Thorell, 1890) were compared with a susceptible population (control) of the same species. Standard protocols were used for biochemical estimation of enzymes. The results showed significantly higher levels of nonspecific esterases and monooxygenases in resistant spiders compared to controls. The activity of GSTs was lower in the resistant spiders. Elevated levels of nonspecific esterases and monooxygenases suggest their role in metabolic resistance in P. sumatrana. The reduced levels of total protein contents revealed its possible consumption to meet energy demands.
Resurgence of the cotton bollworm Helicoverpa armigera in northern Greece associated with insecticide resistance.
Mironidis, George K; Kapantaidaki, Despina; Bentila, Maria; Morou, Evangelia; Savopoulou-Soultani, M; Vontas, John
Helicoverpa armigera has been controlled effectively with chemical insecticides in the major cotton crop production areas of northern Greece for many years. However, a resurgence of the pest was observed in 2010, which significantly affected crop production. During a 4-year survey (2007-2010), we examined the insecticide resistance status of H. armigera populations from two major and representative cotton production areas in northern Greece against seven insecticides (chlorpyrifos, diazinon, methomyl, alpha-cypermethrin, cypermethrin, gamma-cyhalothrin and endosulfan). Full dose-response bioassays on third instar larvae were performed by topical application. Lethal doses at 50% were estimated by probit analysis and resistance factors (RF) were calculated, compared to a susceptible laboratory reference strain. Resistance levels were relatively moderate until 2009, with resistance ratios below 10-fold for organophosphates and carbamates and up to 16-fold for the pyrethroid alpha-cypermethrin. However, resistance rose to 46- and 81-fold for chlorpyrifos and alpha-cypermethrin, respectively in 2010, when the resurgence of the pest was observed. None of the known pyrethroid resistance mutations were found in the pyrethroid-resistant insects. The possible association between resistance and H. armigera resurgence in Greece is discussed.
Resistance to Conventional and New Insecticides in House Flies (Diptera: Muscidae) From Poultry Facilities in Punjab, Pakistan.
Abbas, Naeem; Ali Shad, Sarfraz; Ismail, Muhammad
House flies, Musca domestica L., are pests of poultry facilities and have the ability to develop resistance against different insecticides. This study was conducted to assess the resistance status of house flies to pyrethroid, organophosphate, and novel chemistry insecticides from poultry facilities in Punjab, Pakistan. Five adult house fly populations were studied for their resistance status to selected conventional and novel chemistry insecticides. For four pyrethroids, the range of resistance ratios was 14-55-fold for cypermethrin, 11-45-fold for bifenthrin, 0.84-4.06-fold for deltamethrin, and 4.42-24-fold for lambda-cyhalothrin when compared with a susceptible population. Very low levels of resistance were found to deltamethrin compared with the other pyrethroids. For the three organophosphate insecticides, the range of resistance ratios was 1.70-16-fold for profenofos, 7.50-60-fold for chlorpyrifos, and 4.37-53-fold for triazophos. Very low levels of resistance were found to profenofos compared with the other insecticides. For five novel chemistry insecticides, the range of resistance ratios was 1.20-16.00-fold for fipronil, 3.73-7.16-fold for spinosad, 3.06-23-fold for indoxacarb, 0.96-5.88-fold for abamectin, and 0.56-3.07-fold for emamectin benzoate. Rotation of insecticides with different modes of action showing no or very low resistance may prevent insecticide resistance in house flies. Regular insecticide resistance monitoring and integrated management plans on poultry farms are required to prevent resistance development, field control failures, and environmental pollution.
Assessment of resistance risk to fipronil and cross resistance to other insecticides in the Musca domestica L. (Diptera: Muscidae).
Abbas, Naeem; Ijaz, Mamuna; Shad, Sarfraz Ali; Binyameen, Muhammad
Fipronil, a phenyl-pyrazole insecticide has been used frequently for the control of disease vector house flies, Musca domestica L., (Diptera: Muscidae) worldwide including Pakistan. This experiment was performed to determine the selection and assessment of fipronil resistance evolution along with cross resistance to other three insecticides. After 26 generations of selection, the house fly strain developed 430-fold resistance to fipronil compared to a susceptible strain. Realized heritability (h(2)) of resistance to fipronil was 0.05. The projected rate of resistance development revealed that if 30-90% house flies were selected then a tenfold increase in lethal concentration 50 happened after 95.51-26.59 generations for fipronil (h(2)=0.05, Slope=2.34). At similar slope, if h(2)=0.15, then 31.84-8.86 generations are required for tenfold increase in LC50 at 30-90% selection intensity, respectively. Likewise, if h(2)=0.25, then similar would occur in 19.10-5.32 generations. Differences in any of the variable would affect the rate of resistance development. Selection with fipronil did not increase the level of resistance to lambda-cyhalothrin, profenofos and indoxacarb, suggesting no cross resistance to these insecticides. The results of our study concluded that house flies have the potential to develop resistances following continued selection pressure with fipronil.
Experimental hut evaluation of bednets treated with an organophosphate (chlorpyrifos-methyl or a pyrethroid (lambdacyhalothrin alone and in combination against insecticide-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes
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Corbel Vincent
Full Text Available Abstract Background Pyrethroid resistant mosquitoes are becoming increasingly common in parts of Africa. It is important to identify alternative insecticides which, if necessary, could be used to replace or supplement the pyrethroids for use on treated nets. Certain compounds of an earlier generation of insecticides, the organophosphates may have potential as net treatments. Methods Comparative studies of chlorpyrifos-methyl (CM, an organophosphate with low mammalian toxicity, and lambdacyhalothrin (L, a pyrethroid, were conducted in experimental huts in Côte d'Ivoire, West Africa. Anopheles gambiae and Culex quinquefasciatus mosquitoes from the area are resistant to pyrethroids and organophosphates (kdr and insensitive acetylcholinesterase Ace.1R. Several treatments and application rates on intact or holed nets were evaluated, including single treatments, mixtures, and differential wall/ceiling treatments. Results and Conclusion All of the treatments were effective in reducing blood feeding from sleepers under the nets and in killing both species of mosquito, despite the presence of the kdr and Ace.1R genes at high frequency. In most cases, the effects of the various treatments did not differ significantly. Five washes of the nets in soap solution did not reduce the impact of the insecticides on A. gambiae mortality, but did lead to an increase in blood feeding. The three combinations performed no differently from the single insecticide treatments, but the low dose mixture performed encouragingly well indicating that such combinations might be used for controlling insecticide resistant mosquitoes. Mortality of mosquitoes that carried both Ace.1R and Ace.1S genes did not differ significantly from mosquitoes that carried only Ace.1S genes on any of the treated nets, indicating that the Ace.1R allele does not confer effective resistance to chlorpyrifos-methyl under the realistic conditions of an experimental hut.
Structure, function and applications of carboxylesterases from insects for insecticide resistance.
Yan, Shuaiguo; Cui, Feng; Qiao, Chuanling
Carboxylesterases (EC 188.8.131.52) distribute broadly in insects, and play an important role in the metabolism with various functions. This paper reviews the insect carboxylesterases including the definitions and reaction mechanism, classification, structural context, functions especially on insecticide resistance, and its application.
Monitoring for resistance to organophosphorus and pyrethroid insecticides in varroa mite populations
The occurrence of resistance in Varroa mite populations is a serious threat to the beekeeping industry and crops that rely on the honey bee for pollination. Integrated pest management strategies for control of this pest include the judicious use of insecticides. To monitor field populations of Varro...
A Bioassay for Determining Resistance Levels in Tarnished Plant Bug Populations to Neonicotinoid Insecticides
A laboratory bioassay was developed and used to test field populations of the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), for resistance development to the neonicitinoid insecticides imidacloprid (Trimax®) and thiamethoxam (Centric®). The bioassay determined LC50 values by feeding...
Effects of insecticides on strawberry aphid Chaetosiphon fragaefolii (Cockerell) on resistant and susceptible strawberry genotypes
Strawberry aphid, Chaetosiphon fragaefolii (Cockerell), is the most important vector of strawberry virus. Breeding of genotypes resistant to this pest is an important preventive control measure, which can be compatible with rational insecticide application. The aim of the paper was to determine effects of dimethoate and deltamethrin on C. fragaefolii populations reared on two strawberry genotypes different in susceptibility: susceptible strawberry cultivar ...
Resistance Status to the Insecticides Temephos, Deltamethrin, and Diflubenzuron in Brazilian Aedes aegypti Populations
Bellinato, Diogo Fernandes; Viana-Medeiros, Priscila Fernandes; Araújo, Simone Costa; Martins, Ademir J; Lima, José Bento Pereira; Valle, Denise
Insecticides are still largely applied in public health to control disease vectors. In Brazil, organophosphates (OP) and pyrethroids (PY) are used against Aedes aegypti for years. Since 2009 Insect Growth Regulators (IGR) are also employed in the control of larvae. We quantified resistance to temephos (OP), deltamethrin (PY), and diflubenzuron (IGR) of A. aegypti samples from 12 municipalities distributed throughout the country, collected between 2010 and 2012. High levels of resistance to ne...
Acceptability and perceived side effects of insecticide indoor residual spraying under different resistance management strategies
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Rodríguez Américo David
Full Text Available OBJECTIVE: To assess household acceptability and perceived side effects of residual indoor pyrethroid (PYR, carbamate and organophosphate insecticides sprayed by annual rotation (ROT, spatial mosaic (MOS, and a single insecticide (DDT or PYR in communities of the coastal plain of Chiapas, Mexico. MATERIAL AND METHODS: A questionnaire to assess the acceptability and perceived side effects of indoor insecticides was administered to one member of 30% of the families in eight villages of Chiapas. The association of different insecticide treatments with their responses was evaluated (Chi-square. The intensity of side effects indicated under different treatments was compared in an ordered logistic model, using a severity index as the response variable. RESULTS: Insecticide spraying as a probable cause of symptoms was identified by 2.1% of interviewees. A significantly high percentage of persons with blurred vision, dizziness, sneezing, coughing, numbness, watery eyes, and itching lived in villages under MOS and ROT and a high severity index was significantly associated with ROT treatment. Reduction of mosquito bites and cockroaches were the perceived main benefits, and most villagers that perceived no benefits lived in DDT treated villages. Most of the interviewees welcomed spraying (83.7%, but the smell and having to remove furniture from houses were the main arguments against it. CONCLUSIONS: Acceptability correlated with insecticide spray coverage, although the most frequent suggestion for improvement was to increase the understanding of the objectives of spraying in the communities. The frequency of side effects was low, but higher in localities where a combination of insecticides was applied. This is a limitation for the use of this type of resistance management strategy in public health.
Multiple resistance of Culex vishnui Theobald against four major classes of insecticides in an agricultural area in Sekinchan, Selangor, Malaysia.
Leong, C S; Chen, C D; Low, V L; Karen-Chia, H M; Azidah, A A; Sofian-Azirun, M
The resistance status of riceland Culex vishnui against four major groups of insecticides (i.e., organochlorines, carbamates, organophosphates and pyrethroids) was investigated. Biochemical assays (ESTα, ESTβ, MFO and GST) were also conducted to detect the resistance levels. Throughout a 12-month study period, multiple insecticide resistance was observed in both larvae and adult Cx vishnui. Culex vishnui larvae exhibited low resistance against malathion, temephos and permethrin with resistance ratio (RR) values GST. Spearman rank-order analysis showed that ESTα, ESTβ and GST were involved in multiple resistances in Cx. vishnui. The findings of this study established a baseline of insecticide susceptibility and revealed the effects of agricultural insecticide pressure on the vectors of Japanese encephalitis in Malaysia.
Susceptibility to Insecticides and Ecological Fitness in Resistant Rice Varieties of Field Nilaparvata lugens Stål Population Free from Insecticides in Laboratory
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YANG Ya-jun; DONG Bi-qin; XU Hong-xing; ZHENG Xu-song; K.L.HEONG; LU Zhong-xian
A population of rice brown planthopper (BPH) Nilaparvata lugens collected from a paddy field in Hangzhou was successively reared on susceptible rice Taichung Native 1 (TN1) in a laboratory free from insecticides for more than 14 generations. The changes in susceptibility to insecticides and ecological fitness on different resistant rice varieties were monitored in each generation. The resistance ratio to imidacloprid sharply declined with the succession of rearing generations without insecticides from 359.94-fold at F1 to 6.50-fold at F14 compared with the susceptible strain, and the resistance ratio to chlorpyrifos was from 9.90-fold at F1 to 5.94-fold at F14. Nymphal duration and weights of newly hatched female adults were significantly affected by rice variety, generation and their interactions, but nymphal survival was significantly affected by the generation only. The ratio of brachypterous adults in males was affected by the generation and generation × variety interaction, whereas no difference was found in females. Nymphal duration extended with increasing generations, and the female nymphal duration was shorter in the susceptible variety TN1 than those in the resistant varieties IR26 and IR36. In addition, the female adult weight in TN1 was higher than those in IR26 and IR36. These results indicated that the resistance of field BPH population to insecticides was reversed after several generations of no-exposure to insecticides, and the ecological fitness in TN1 was higher than those in IR26 and IR36. These findings suggested the rational and reduced use of insecticides in combination with the manipulation of resistant rice varieties would be effective for BPH management.
Kinetic characters and resistance to inhibition of crude and purified brain acetylcholinesterase of three freshwater fishes by organophosphates.
Shaonan, Li; Xianchuan, Xie; Guonian, Zhu; Yajun, Tan
Acetylcholinesterase (AChE) was purified from the brain of three fresh-water fishes, topmouth gudgeon (Pseudorasbora parva), goldfish (Carassius auratus auratus) and rainbow trout (Oncorrhychus mykiss, formerly named Salmo gairdneri) by PEG2000/phosphate-salt two phases extraction, DEAE-Sephadex A-50 and Sephadex G-200 chromatography. Kinetic characters and resistance to inhibition of crude and purified enzymes by organophosphates were then studied. Although the crude enzyme from the trout displayed a different specific activity, kinetic curve, Vmax, and sensitivity to inhibition by oxidized malathion and triazopos compared with the two cyprinoids (i.e. topmouth gudgeon and goldfish), the purified enzymes of all the three species showed no significant difference in all aspects. The result suggested a negligible intrinsic difference of brain AChEs among the tested species.
A whole transcriptomal linkage analysis of gene co-regulation in insecticide resistant house flies, Musca domestica
Background Studies suggest that not only is insecticide resistance conferred via multiple gene up-regulation, but it is mediated through the interaction of regulatory factors. However, no regulatory factors in insecticide resistance have yet been identified, and there has been no examination of the regulatory interaction of resistance genes. Our current study generated the first reference transcriptome from the adult house fly and conducted a whole transcriptome analysis for the multiple inse...
Contrasting patterns of insecticide resistance and knockdown resistance (kdr in Aedes aegypti populations from Jacarezinho (Brazil after a Dengue Outbreak
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Oscar Alexander Aguirre-Obando
Full Text Available ABSTRACT After a dengue outbreak, the knowledge on the extent, distribution and mechanisms of insecticide resistance is essential for successful insecticide-based dengue control interventions. Therefore, we evaluated the potential changes to insecticide resistance in natural Aedes aegypti populations to Organophosphates (OP and Pyrethroids (PY after chemical vector control interventions. After a Dengue outbreak in 2010, A. aegypti mosquitoes from the urban area of Jacarezinho (Paraná, Brazil were collected in 2011 and 2012. Insecticide resistance to OP Temephos was assessed in 2011 and 2012 by dose–response bioassays adopting WHO-based protocols. Additionally, in both sampling, PY resistance was also investigated by the Val1016Ile mutation genotyping. In 2011, a random collection of mosquitoes was carried out; while in 2012, the urban area was divided into four regions where mosquitoes were sampled randomly. Bioassays conducted with larvae in 2011 (82 ± 10%; RR95 = 3.6 and 2012 (95 ± 3%; RR95 = 2.5 indicated an incipient altered susceptibility to Temephos. On the other hand, the Val1016IIe mutation analysis in 2011, presented frequencies of the 1016Ilekdr allele equal to 80%. Nevertheless, in 2012, when the urban area of Jacarezinho was analyzed as a single unit, the frequency of the mutant allele was 70%. Additionally, the distribution analysis of the Val1016Ile mutation in 2012 showed the mutant allele frequencies ≥60% in all regions. These outcomes indicated the necessity of developing alternative strategies such as insecticide rotations for delaying the evolution of resistance.
Mating behavior and reproductive output in insecticide-resistant and -susceptible strains of the maize weevil (Sitophilus zeamais)
Insecticide resistance is the most broadly recognized and well studied ecological problem resulting from intensive insecticide use, which also provides useful evolutionary models of newly adapted phenotypes to changing environments. Two common assumptions in such population-oriented models are the e...
First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions
Howard, A.F.V.; N'Guessan, R.; Koenraadt, C.J.M.; Asidi, A.; Farenhorst, M.; Akogbeto, M.; Knols, B.G.J.; Takken, W.
Background - Insecticide-resistant mosquitoes are compromising the ability of current mosquito control tools to control malaria vectors. A proposed new approach for mosquito control is to use entomopathogenic fungi. These fungi have been shown to be lethal to both insecticide-susceptible and insecti
Insecticide resistance in malaria vector mosquitoes at four localities in Ghana, West Africa
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Kaiser Maria L
Full Text Available Abstract Background Malaria vector control programmes that rely on insecticide-based interventions such as indoor house spraying with residual insecticides or insecticide treated bed nets, need to base their decision-making process on sound baseline data. More and more commercial entities in Africa, such as mining companies, are realising the value to staff productivity of controlling malaria transmission in their areas of operation. This paper presents baseline entomological data obtained during surveys conducted for four mining operations in Ghana, West Africa. Results The vast majority of the samples were identified as Anopheles gambiae S form with only a few M form specimens being identified from Tarkwa. Plasmodium falciparum infection rates ranged from 4.5 to 8.6% in An. gambiae and 1.81 to 8.06% in An. funestus. High survival rates on standard WHO bioassay tests were recorded for all insecticide classes except the organophosphates that showed reasonable mortality at all locations (i.e. > 90%. The West African kdr mutation was detected and showed high frequencies in all populations. Conclusions The data highlight the complexity of the situation prevailing in southern Ghana and the challenges facing the malaria vector control programmes in this region. Vector control programmes in Ghana need to carefully consider the resistance profiles of the local mosquito populations in order to base their resistance management strategies on sound scientific data.
DNA sequencing reveals the midgut microbiota of diamondback moth, Plutella xylostella (L. and a possible relationship with insecticide resistance.
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Xiaofeng Xia
Full Text Available BACKGROUND: Insect midgut microbiota is important in host nutrition, development and immune response. Recent studies indicate possible links between insect gut microbiota and resistance to biological and chemical toxins. Studies of this phenomenon and symbionts in general have been hampered by difficulties in culture-based approach. In the present study, DNA sequencing was used to examine the midgut microbiota of diamondback moth (DBM, Plutella xylostella (L., a destructive pest that attacks cruciferous crops worldwide. Its ability to develop resistance to many types of synthetic insecticide and even Bacillus thuringiensis toxins makes it an important species to study. METHODOLOGY/PRINCIPAL FINDINGS: Bacteria of the DBM larval midgut in a susceptible and two insecticide (chlorpyrifos and fipronil resistant lines were examined by Illumina sequencing sampled from an insect generation that was not exposed to insecticide. This revealed that more than 97% of the bacteria were from three orders: Enterobacteriales, Vibrionales and Lactobacillales. Both insecticide-resistant lines had more Lactobacillales and the much scarcer taxa Pseudomonadales and Xanthomonadales with fewer Enterobacteriales compared with the susceptible strain. Consistent with this, a second study observed an increase in the proportion of Lactobacillales in the midgut of DBM individuals from a generation treated with insecticides. CONCLUSIONS/SIGNIFICANCE: This is the first report of high-throughput DNA sequencing of the entire microbiota of DBM. It reveals differences related to inter- and intra-generational exposure to insecticides. Differences in the midgut microbiota among susceptible and insecticide-resistant lines are independent of insecticide exposure in the sampled generations. While this is consistent with the hypothesis that Lactobacillales or other scarcer taxa play a role in conferring DBM insecticide resistance, further studies are necessary to rule out other
Bollgard cotton and resistance of tobacco budworm (Lepidoptera: Noctuidae) to conventional insecticides in southern Tamaulipas, Mexico.
Terán-Vargas, A P; Rodríguez, J C; Blanco, C A; Martínez-Carrillo, J L; Cibrián-Tovar, J; Sánchez-Arroyo, H; Rodríguez-del-Bosque, L A; Stanley, D
Insecticide susceptibility in tobacco budworm, Heliothis virescens (F.) (Lepidoptera: Noctuidae), was determined for 8 yr (1991-2001) with larvae sampled from cotton in southern Tamaulipas, Mexico. Before 1996, when Bollgard cotton expressing the Cry1A(c) delta-endotoxin was introduced into the region, two important patterns were documented. The first was economically significant increases in resistance to certain insecticide groups. The second was occurrence of virtually complete control failures in the field during 1994 and 1995. The largest resistance changes were recorded for the type II pyrethroids cypermethrin and deltamethrin. These products are the most widely used products in the region. Resistance ratios for these products increased up to > 100-fold from 1991 to 1995. After 1996, the resistance levels declined. These findings did not occur with other products of scant use (e.g., permethrin, profenofos, and endosulfan) or low tobacco budworm efficacy coupled to a high use pattern (e.g., methyl parathion). This clear trend toward reversal of resistance to type II pyrethroids can be understood, in part, with respect to two factors: 1) the high adoption rate of transgenic cotton in the region, from 31.2% in the beginning (1996) to approximately 90% in 1998; this has considerably curbed the use of synthetic insecticides, with the attending loss of selection pressure on this pest; and 2) the potential immigration to the region of susceptible tobacco budworms from cultivated and wild suitable hosts as well as from transgenic cotton might have influenced the pest population as a whole. The influence of transgenic cotton on southern Tamaulipas can be more clearly seen by the drastic reduction of insecticide use to control this important pest. Now tobacco budworms in this region are susceptible to type II pyrethroids. Two effective and fundamentally different pest management tools are now available to cotton growers in southern Tamaulipas: transgenic cotton
Insecticide resistance in Anopheles gambiae from south-western Chad, Central Africa
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Etang Josiane
Full Text Available Abstract Background Indoor residual spraying and insecticide-treated nets (ITN are essential components of malaria vector control in Africa. Pyrethroids are the only recommended compounds for nets treatment because they are fast-acting insecticides with low mammalian toxicity. However, there is growing concern that pyrethroid resistance may threaten the sustainability of ITN scaling-up programmes. Here, insecticide susceptibility was investigated in Anopheles gambiae sensu lato from an area of large scale ITN distribution programme in south-western Chad. Methods Susceptibility to 4% DDT, 0.05% deltamethrin, 0.75% permethrin, 0.1% bendiocarb and 5% malathion was assessed using the WHO standard procedures for adult mosquitoes. Tests were carried out with two to four days-old, non-engorged female mosquitoes. The An. gambiae Kisumu strain was used as a reference. Knockdown effect was recorded every 5 min and mortality scored 24 h after exposure. Mosquitoes were identified to species and molecular form by PCR-RFLP and genotypes at the kdr locus were determined in surviving specimens by Hot Oligonucleotide Ligation Assay (HOLA. Results During this survey, full susceptibility to malathion was recorded in all samples. Reduced susceptibility to bendiocarb (mortality rate of 96.1% was found in one sample out of nine assayed. Increased tolerance to pyrethroids was detected in most samples (8/9 with mortality rates ranging from 70.2 to 96.6% for deltamethrin and from 26.7 to 96.3% for permethrin. Pyrethroid tolerance was not associated with a significant increase of knock-down times. Anopheles arabiensis was the predominant species of the An. gambiae complex in the study area, representing 75 to 100% of the samples. Screening for kdr mutations detected the L1014F mutation in 88.6% (N = 35 of surviving An. gambiae sensu stricto S form mosquitoes. All surviving An. arabiensis (N = 49 and M form An. gambiae s.s. (N = 1 carried the susceptible allele
Report of resistance to the neonicotinoid insecticide imidacloprid in Trialeurodes vaporariorum (Hemiptera: Aleyrodidae).
Gorman, Kevin; Devine, Gregor; Bennison, Jude; Coussons, Peter; Punchard, Neville; Denholm, Ian
Susceptibilities of UK and mainland European samples of Trialeurodes vaporariorum (Westwood) to the neonicotinoid insecticide imidacloprid were investigated over a 7 year period. All 24 strains collected between 1997 and 2003 showed similar baseline levels of susceptibility to that of a known susceptible laboratory strain when exposed to a diagnostic concentration (128 mg L(-1)) of formulated imidacloprid. Two samples collected during 2004, one from the UK and one from The Netherlands, demonstrated reduced susceptibility at this concentration. Using dose-response assays, the presence of resistant individuals was disclosed in both these strains; some individuals were unaffected at doses high enough to induce phytotoxic effects. This report represents the first confirmed cases of neonicotinoid resistance inducing control failures in T. vaporariorum, and highlights a need for careful vigilance to sustain the effectiveness of imidacloprid and related neonicotinoid insecticides.
Comparative and functional triatomine genomics reveals reductions and expansions in insecticide resistance-related gene families
Traverso, Lucila; Lavore, Andrés; Sierra, Ivana; Palacio, Victorio; Martinez-Barnetche, Jesús; Latorre-Estivalis, José Manuel; Mougabure-Cueto, Gaston; Francini, Flavio; Lorenzo, Marcelo G.; Rodríguez, Mario Henry; Ons, Sheila; Rivera-Pomar, Rolando V.
Background Triatomine insects are vectors of Trypanosoma cruzi, a protozoan parasite that is the causative agent of Chagas' disease. This is a neglected disease affecting approximately 8 million people in Latin America. The existence of diverse pyrethroid resistant populations of at least two species demonstrates the potential of triatomines to develop high levels of insecticide resistance. Therefore, the incorporation of strategies for resistance management is a main concern for vector control programs. Three enzymatic superfamilies are thought to mediate xenobiotic detoxification and resistance: Glutathione Transferases (GSTs), Cytochromes P450 (CYPs) and Carboxyl/Cholinesterases (CCEs). Improving our knowledge of key triatomine detoxification enzymes will strengthen our understanding of insecticide resistance processes in vectors of Chagas' disease. Methods and findings The discovery and description of detoxification gene superfamilies in normalized transcriptomes of three triatomine species: Triatoma dimidiata, Triatoma infestans and Triatoma pallidipennis is presented. Furthermore, a comparative analysis of these superfamilies among the triatomine transcriptomes and the genome of Rhodnius prolixus, also a triatomine vector of Chagas' disease, and other well-studied insect genomes was performed. The expression pattern of detoxification genes in R. prolixus transcriptomes from key organs was analyzed. The comparisons reveal gene expansions in Sigma class GSTs, CYP3 in CYP superfamily and clade E in CCE superfamily. Moreover, several CYP families identified in these triatomines have not yet been described in other insects. Conversely, several groups of insecticide resistance related enzymes within each enzyme superfamily are reduced or lacking in triatomines. Furthermore, our qRT-PCR results showed an increase in the expression of a CYP4 gene in a T. infestans population resistant to pyrethroids. These results could point to an involvement of metabolic
Insecticide resistance and its underlying mechanisms in field populations of Aedes aegypti adults (Diptera: Culicidae) in Singapore
Koou, Sin-Ying; Chong, Chee-Seng; Vythilingam, Indra; Lee, Chow-Yang; Ng, Lee-Ching
Background In Singapore, dose–response bioassays of Aedes aegypti (L.) adults have been conducted, but the mechanisms underlying resistance to insecticides remain unclear. In this study, we evaluated insecticide resistance and its underlying mechanism in field populations of Ae. aegypti adults. Methods Seven populations of Ae. aegypti were collected from public residential areas and assays were conducted according to WHO guidelines to determine their susceptibility to several commonly used in...
The Anopheles gambiae detoxification chip: A highly specific microarray to study metabolic-based insecticide resistance in malaria vectors
Metabolic pathways play an important role in insecticide resistance, but the full spectra of the genes involved in resistance has not been established. We constructed a microarray containing unique fragments from 230 Anopheles gambiae genes putatively involved in insecticide metabolism [cytochrome P450s (P450s), GSTs, and carboxylesterases and redox genes, partners of the P450 oxidative metabolic complex, and various controls]. We used this detox chip to monitor the expression of the detoxify...
Impact of insecticide-treated nets on wild pyrethroid resistant Anopheles epiroticus population from southern Vietnam tested in experimental huts
Trung Ho; Speybroeck Niko; Berkvens Dirk; Chinh Vu; Van Bortel Wim; Coosemans Marc
Abstract Background In this study, the efficacy of insecticide-treated nets was evaluated in terms of deterrence, blood-feeding inhibition, induced exophily and mortality on a wild resistant population of Anopheles epiroticus in southern Vietnam, in order to gain insight into the operational consequences of the insecticide resistance observed in this malaria vector in the Mekong delta. Method An experimental station, based on the model of West Africa and adapted to the behaviour of the target...
Costly Inheritance and the Persistence of Insecticide Resistance in Aedes aegypti Populations.
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Helio Schechtman
Full Text Available Global emergence of arboviruses is a growing public health concern, since most of these diseases have no vaccine or prevention treatment available. In this scenario, vector control through the use of chemical insecticides is one of the most important prevention tools. Nevertheless, their effectiveness has been increasingly compromised by the development of strong resistance observed in field populations, even in spite of fitness costs usually associated to resistance. Using a stage-structured deterministic model parametrised for the Aedes aegypti--the main vector for dengue--we investigated the persistence of resistance by studying the time for a population which displays resistance to insecticide to revert to a susceptible population. By means of a comprehensive series of in-silico experiments, we studied this reversal time as a function of fitness costs and the initial presence of the resistance allele in the population. The resulting map provides both a guiding and a surveillance tool for public health officers to address the resistance situation of field populations. Application to field data from Brazil indicates that reversal can take, in some cases, decades even if fitness costs are not small. As by-products of this investigation, we were able to fit very simple formulas to the reversal times as a function of either cost or initial presence of the resistance allele. In addition, the in-silico experiments also showed that density dependent regulation plays an important role in the dynamics, slowing down the reversal process.
Inhibition of acetylcholinesterase by Tea Tree oil.
Mills, Clive; Cleary, Brian J; Gilmer, John F; Walsh, John J
Pediculosis is a widespread condition reported in schoolchildren. Treatment most commonly involves the physical removal of nits using fine-toothcombs and the chemical treatment of adult lice and eggs with topical preparations. The active constituents of these preparations frequently exert their effects through inhibition of acetylcholinesterase (AChE, EC 184.108.40.206). Increasing resistance to many preparations has led to the search for more effective treatments. Tea Tree oil, otherwise known as Melaleuca oil, has been added to several preparations as an alternative treatment of head lice infestations. In this study two major constituents of Tea Tree oil, 1,8-cineole and terpinen-4-ol, were shown to inhibit acetylcholinesterase at IC50 values (inhibitor concentrations required to give 50% inhibition) of 0.04 and 10.30 mM, respectively. Four samples of Tea Tree oil tested (Tisserand, Body Treats, Main Camp and Irish Health Culture Association Pure Undiluted) showed anticholinesterase activity at IC50 values of 0.05, 0.10, 0.08 and 0.11 microL mL(-1), respectively. The results supported the hypothesis that the insecticidal activity of Tea Tree oil was attributable, in part, to the anticholinesterase activity of Tea Tree oil.
Deltamethrin-mediated survival, behavior, and oenocyte morphology of insecticide-susceptible and resistant yellow fever mosquitos (Aedes aegypti).
Marriel, Nadja Biondine; Tomé, Hudson Vaner Ventura; Guedes, Raul Carvalho Narciso; Martins, Gustavo Ferreira
Insecticide use is the prevailing control tactic for the mosquito Aedes aegypti, a vector of several human viruses, which leads to ever-increasing problems of insecticide resistance in populations of this insect pest species. The underlying mechanisms of insecticide resistance may be linked to the metabolism of insecticides by various cells, including oenocytes. Oenocytes are ectodermal cells responsible for lipid metabolism and detoxification. The goal of this study was to evaluate the sublethal effects of deltamethrin on survival, behavior, and oenocyte structure in the immature mosquitoes of insecticide-susceptible and resistant strains of A. aegypti. Fourth instar larvae (L4) of both strains were exposed to different concentrations of deltamethrin (i.e., 0.001, 0.003, 0.005, and 0.007 ppm). After exposure, L4 were subjected to behavioral bioassays. Insecticide effects on cell integrity after deltamethrin exposure (at 0.003 or 0.005 ppm) were assessed by processing pupal oenocytes for transmission electron microscopy or TUNEL reaction. The insecticide resistant L4 survived all the tested concentrations, whereas the 0.007-ppm deltamethrin concentration had lethal effects on susceptible L4. Susceptible L4 were lethargic and exhibited less swimming activity than unexposed larvae, whereas the resistant L4 were hyperexcited following exposure to 0.005 ppm deltamethrin. No sublethal effects and no significant cell death were observed in the oenocytes of either susceptible or resistant insects exposed to deltamethrin. The present study illustrated the different responses of susceptible and resistant strains of A. aegypti following exposure to sublethal concentration of deltamethrin, and demonstrated how the behavior of the immature stage of the two strains varied, as well as oenocyte structure following insecticide exposure.
Using mass-release of engineered insects to manage insecticide resistance
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Alphey, Nina [University of Oxford (United Kingdom). Dept. of Zoology; Alphey, Luke [Oxitec Limited, Oxford (United Kingdom); Coleman, Paul G. [London School of Hygiene and Tropical Medicine (United Kingdom). Dept. of Infectious and Tropical Diseases; Donnelly, Christl A. [Imperial College Faculty of Medicine, London (United Kingdom). Dept. of Infectious Disease Epidemiology
Transgenic crops expressing insecticidal toxins derived from Bacillus thuringiensis (Bt) are widely used to control insect pests. The benefits of such crops would be lost if resistance to the toxins spread to a significant proportion of the pest population. The main resistance management method, mandatory in the US, is the high-dose/refuge strategy, requiring nearby refuges of toxin-free crops, and the use of toxin doses sufficiently high to kill not only wild type insects but also insects heterozygous for a resistance allele, thereby rendering the resistance functionally recessive. We propose that mass-release of harmless toxin-sensitive insects could substantially delay or even reverse the spread of resistance. Mass-release of such insects is an integral part of RIDL, a genetics-based method of pest control related to the Sterile Insect Technique. We used a population genetic mathematical model to analyze the effects of releasing male insects homozygous for a female-specific dominant lethal genetic construct, and concluded that this RIDL strategy could form an effective component of a resistance management scheme for insecticidal plants and other toxins. (author)
Functional characterization of glutathione S-transferases associated with insecticide resistance in Tetranychus urticae.
Pavlidi, Nena; Tseliou, Vasilis; Riga, Maria; Nauen, Ralf; Van Leeuwen, Thomas; Labrou, Nikolaos E; Vontas, John
The two-spotted spider mite Tetranychus urticae is one of the most important agricultural pests world-wide. It is extremely polyphagous and develops resistance to acaricides. The overexpression of several glutathione S-transferases (GSTs) has been associated with insecticide resistance. Here, we functionally expressed and characterized three GSTs, two of the delta class (TuGSTd10, TuGSTd14) and one of the mu class (TuGSTm09), which had been previously associated with striking resistance phenotypes against abamectin and other acaricides/insecticides, by transcriptional studies. Functional analysis showed that all three GSTs were capable of catalyzing the conjugation of both 1-chloro-2,4 dinitrobenzene (CDNB) and 1,2-dichloro-4-nitrobenzene(DCNB) to glutathione (GSH), as well as exhibiting GSH-dependent peroxidase activity toward Cumene hydroperoxide (CumOOH). The steady-state kinetics of the T. urticae GSTs for the GSH/CDNB conjugation reaction were determined and compared with other GSTs. The interaction of the three recombinant proteins with several acaricides and insecticides was also investigated. TuGSTd14 showed the highest affinity toward abamectin and a competitive type of inhibition, which suggests that the insecticide may bind to the H-site of the enzyme. The three-dimensional structure of the TuGSTd14 was predicted based on X-ray structures of delta class GSTs using molecular modeling. Structural analysis was used to identify key structural characteristics and to provide insights into the substrate specificity and the catalytic mechanism of TuGSTd14.
The Relationship Between Resistance to Controlled Atmosphere and Insecticides of Liposcelis bostrychophila Badonnel (Psocoptera:Liposcelididae)
Institute of Scientific and Technical Information of China (English)
DING Wei; ZHAO Zhi-mo; WANG Jin-jun; TAO Hui-ying; ZHANG Yong-qiang
The cross resistance of four resistant strains of Liposcelis bostrychophila Badonnel, an important stored-product insect pest, was investigated. These four strains included the HCO2-R (hypercarbia-resistant strain), HCLO-R (hypoxia and hypercarbia resistant strain),DDVP-R (DDVP-resistant strain) and PH3-R (PH3-resistant strain). The results indicated that there were cross-resistances between CA and insecticides, and the quantities of the cross-resistance were different. The cross-resistance factor (RF) of HCO2-R to hypoxia and hypercarbia was 3.2458, whilst, that of HCLO-R to hypercarbia was 1.8280. The RF of DDVP-R to PH3 was 3.9614, whilst, that of PH3-R to DDVP was 2.7852. The RF values of DDVPR and PH3-R to hypercarbia were 1.3550 and 1.1816, respectively. However, the RF of HCO2-R to DDVP was 2.1372. There also was a low cross-resistance between DDVP-R and HCO2-R. The RF of HCO2-R to PH3 was 3.3698. This sugqested that the insects resistant to high CO2concentration atmosphere would develop significant resistance to PH3. However, the insects resistant to PH3 remain sensitive to hypercarbia atmosphere. Both DDVP-R and PH3-R developed resistance to high CO2 treatment. There was a low cross-resistance between DDVP-R and HCLO-R. The insects resistant to hypoxia and hypercarbia were very sensitive to DDVP. There also was cross-resistance between HCLO-R and PH3-R, but the resistance of PH3-R to hypoxia and hypercarbia was lower than that of HCLO-R to PH3. The difference of the overlapping and separate values indicated that there were differences in the intercross-resistance of four resistant strains.
Insecticide resistance monitoring and correlation analysis of insecticides in field populations of the brown planthopper Nilaparvata lugens (stål) in China 2012-2014.
Zhang, Xiaolei; Liao, Xun; Mao, Kaikai; Zhang, Kaixiong; Wan, Hu; Li, Jianhong
The brown planthopper is a serious rice pest in China. Chemical insecticides have been considered a satisfactory means of controlling the brown planthopper. In the present study, we determined the susceptibility of twenty-one populations of Nilaparvata lugens to eleven insecticides by a rice-stem dipping method from 2012 to 2014 in eight provinces of China. These field-collected populations of N. lugens had developed high levels of resistance to imidacloprid (resistant ratio, RR=233.3-2029-fold) and buprofezin (RR=147.0-1222). Furthermore, N. lugens showed moderate to high levels of resistance to thiamethoxam (RR=25.9-159.2) and low to moderate levels of resistance to dinotefuran (RR=6.4-29.1), clothianidin (RR=6.1-33.6), ethiprole (RR=11.5-71.8), isoprocarb (RR=17.1-70.2), and chlorpyrifos (RR=7.4-30.7). In contrast, the susceptibility of N. lugens to etofenprox (RR=1.1-4.9), thiacloprid (RR=2.9-8.2) and acetamiprid (RR=2.7-26.2) remained susceptible to moderate levels of resistance. Significant correlations were detected between the LC50 values of imidacloprid and thiamethoxam, dinotefuran, buprofezin, and etofenprox, as well as between clothianidin and thiamethoxam, dinotefuran, ethiprole, acetamiprid, and thiacloprid. Similarly, significant correlations were observed between chlorpyrifos and etofenprox, acetamiprid and thiacloprid. Additionally, the activity of the detoxification enzymes of N. lugens showed a significant correlation with the log LC50 values of imidacloprid, dinotefuran and ethiprole. These results will be beneficial for effective insecticide resistance management strategies to prevent or delay the development of insecticide resistance.
Impact of insecticide-treated nets on wild pyrethroid resistant Anopheles epiroticus population from southern Vietnam tested in experimental huts
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Trung Ho
Full Text Available Abstract Background In this study, the efficacy of insecticide-treated nets was evaluated in terms of deterrence, blood-feeding inhibition, induced exophily and mortality on a wild resistant population of Anopheles epiroticus in southern Vietnam, in order to gain insight into the operational consequences of the insecticide resistance observed in this malaria vector in the Mekong delta. Method An experimental station, based on the model of West Africa and adapted to the behaviour of the target species, was built in southern Vietnam. The study design was adapted from the WHO phase 2 guidelines. The study arms included a conventionally treated polyester net (CTN with deltamethrin washed just before exhaustion, the WHO recommended long-lasting insecticidal net (LLIN PermaNet 2.0® unwashed and 20 times washed and PermaNet 3.0®, designed for the control of pyrethroid resistant vectors, unwashed and 20 times washed. Results The nets still provided personal protection against the resistant An. epiroticus population. The personal protection ranged from 67% for deltamethrin CTN to 85% for unwashed PermaNet 3.0. Insecticide resistance in the An. epiroticus mosquitoes did not seem to alter the deterrent effect of pyrethroids. A significant higher mortality was still observed among the treatment arms despite the fact that the An. epiroticus population is resistant against the tested insecticides. Conclusion This study shows that CTN and LLINs still protect individuals against a pyrethroid resistant malaria vector from the Mekong region, where insecticide resistance is caused by a metabolic mechanism. In the light of a possible elimination of malaria from the Mekong region these insights in operational consequences of the insecticide resistance on control tools is of upmost importance.
Insecticide resistance in populations of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), from the state of Pernambuco, Brazil.
Santos, V C; de Siqueira, H A A; da Silva, J E; de Farias, M J D C
The diamondback moth Plutella xylostella (L.) has a great economic importance in Brassicaceae crops in many parts of the world. Recurrent infestations of this pest in growing areas of Pernambuco state, Brazil, have led farmers to frequently spray their crops with insecticides. However, control failures by several insecticides have been alleged by farmers. The objective of this study was to check whether resistance to insecticides could explain these control failures in P. xylostella. Populations of P. xylostella from Pernambuco were collected between January and April 2009. The resistance ratios of P. xylostella populations were compared among five different active ingredients: abamectin, methomyl, lufenuron, indoxacarb, and diafenthiuron by leaf dipping bioassays using foliar discs of kale leaves. Mortality data were submitted to probit analysis. The P. xylostella populations showed variable response and significant resistance to one or more insecticides. The population from Bezerros County exhibited the highest resistance ratios to indoxacarb (25.3 times), abamectin (61.7 times), and lufenuron (705.2 times), when compared to the reference population. The populations from Bonito and Jupi Counties were 33.0 and 12.0 times more resistant to lufenuron and abamectin, respectively, when compared with the reference population. Resistance to methomyl was the least common, but not less important, in at least four populations. These results indicated that control failures were associated with resistance by some of the evaluated insecticides, reinforcing the need for resistance management in areas of the state of Pernambuco.
Mechanisms of insecticide resistance in field populations of Aedes aegypti (L.) from Quintana Roo, Southern Mexico.
Flores, Adriana E; Grajales, Jaime Salomon; Salas, Ildefonso Fernandez; Garcia, Gustavo Ponce; Becerra, Ma Haydee Loaiza; Lozano, Saul; Brogdon, William G; Black, William C; Beaty, Barry
Potential insecticide-resistance mechanisms were studied with the use of biochemical assays in Aedes aegypti (L.) collected from 5 municipalities representing the north part of Quintana Roo: Benito Juarez, Cozumel, Isla Mujeres, Lazaro Cardenas, and Solidaridad. The activities of alpha and beta esterases, mixed-function oxidases (MFO), glutathione-S-transferase (GST), acethylcholinesterase (AChE), and insensitive acethylcholinesterase (iAChE) were assayed in microplates. Three replicates were performed for each enzyme and 60 males and 60 females were analyzed in each population. The New Orleans (NO) susceptible strain of Ae. aegypti was used as a susceptible reference and the threshold criteria for each enzyme were the highest NO absorbance values. In none of the 6 tests were absorbance values correlated in males and females. alpha esterases were elevated in Benito Juarez, Cozumel females and in Lazaro Cardenas males and females. beta esterases were elevated in Benito Juarez, Cozumel females and in Cozumel and Lazaro Cardenas males. Elevated esterases suggest potential insecticide-resistance mechanisms against organophosphate, carbamate, and some pyrethroid insecticides. Slightly elevated levels of MFOs appeared in Lazaro Cardenas females and in Cozumel, Isla Mujeres, and Solidaridad males. Mechanisms involving iAChE or GST were not apparent.
Use of mutagenesis, genetic mapping and next generation transcriptomics to investigate insecticide resistance mechanisms.
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Predrag Kalajdzic
Full Text Available Insecticide resistance is a worldwide problem with major impact on agriculture and human health. Understanding the underlying molecular mechanisms is crucial for the management of the phenomenon; however, this information often comes late with respect to the implementation of efficient counter-measures, particularly in the case of metabolism-based resistance mechanisms. We employed a genome-wide insertional mutagenesis screen to Drosophila melanogaster, using a Minos-based construct, and retrieved a line (MiT[w(-]3R2 resistant to the neonicotinoid insecticide Imidacloprid. Biochemical and bioassay data indicated that resistance was due to increased P450 detoxification. Deep sequencing transcriptomic analysis revealed substantial over- and under-representation of 357 transcripts in the resistant line, including statistically significant changes in mixed function oxidases, peptidases and cuticular proteins. Three P450 genes (Cyp4p2, Cyp6a2 and Cyp6g1 located on the 2R chromosome, are highly up-regulated in mutant flies compared to susceptible Drosophila. One of them (Cyp6g1 has been already described as a major factor for Imidacloprid resistance, which validated the approach. Elevated expression of the Cyp4p2 was not previously documented in Drosophila lines resistant to neonicotinoids. In silico analysis using the Drosophila reference genome failed to detect transcription binding factors or microRNAs associated with the over-expressed Cyp genes. The resistant line did not contain a Minos insertion in its chromosomes, suggesting a hit-and-run event, i.e. an insertion of the transposable element, followed by an excision which caused the mutation. Genetic mapping placed the resistance locus to the right arm of the second chromosome, within a ∼1 Mb region, where the highly up-regulated Cyp6g1 gene is located. The nature of the unknown mutation that causes resistance is discussed on the basis of these results.
Staggered larval time-to-hatch and insecticide resistance in the major malaria vector Anopheles gambiae S form
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Coetzee Maureen
Full Text Available Abstract Background Anopheles gambiae is a major vector of malaria in the West African region. Resistance to multiple insecticides has been recorded in An. gambiae S form in the Ahafo region of Ghana. A laboratory population (GAH established using wild material from this locality has enabled a mechanistic characterization of each resistance phenotype as well as an analysis of another adaptive characteristic - staggered larval time-to-hatch. Methods Individual egg batches obtained from wild caught females collected from Ghana and the Republic of the Congo were monitored for staggered larval time-to-hatch. In addition, early and late larval time-to-hatch sub-colonies were selected from GAH. These selected sub-colonies were cross-mated and their hybrid progeny were subsequently intercrossed and back-crossed to the parental strains. The insecticide susceptibilities of the GAH base colony and the time-to-hatch selected sub-colonies were quantified for four insecticide classes using insecticide bioassays. Resistance phenotypes were mechanistically characterized using insecticide-synergist bioassays and diagnostic molecular assays for known reduced target-site sensitivity mutations. Results Anopheles gambiae GAH showed varying levels of resistance to all insecticide classes. Metabolic detoxification and reduced target-site sensitivity mechanisms were implicated. Most wild-caught families showed staggered larval time-to-hatch. However, some families were either exclusively early hatching or late hatching. Most GAH larvae hatched early but many egg batches contained a proportion of late hatching larvae. Crosses between the time-to-hatch selected sub-colonies yielded ambiguous results that did not fit any hypothetical models based on single-locus Mendelian inheritance. There was significant variation in the expression of insecticide resistance between the time-to-hatch phenotypes. Conclusions An adaptive response to the presence of multiple insecticide
Synergy in efficacy of fungal entomopathogens and permethrin against West African insecticide-resistant Anopheles gambiae mosquitoes.
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Marit Farenhorst
Full Text Available BACKGROUND: Increasing incidences of insecticide resistance in malaria vectors are threatening the sustainable use of contemporary chemical vector control measures. Fungal entomopathogens provide a possible additional tool for the control of insecticide-resistant malaria mosquitoes. This study investigated the compatibility of the pyrethroid insecticide permethrin and two mosquito-pathogenic fungi, Beauveria bassiana and Metarhizium anisopliae, against a laboratory colony and field population of West African insecticide-resistant Anopheles gambiae s.s. mosquitoes. METHODOLOGY/FINDINGS: A range of fungus-insecticide combinations was used to test effects of timing and sequence of exposure. Both the laboratory-reared and field-collected mosquitoes were highly resistant to permethrin but susceptible to B. bassiana and M. anisopliae infection, inducing 100% mortality within nine days. Combinations of insecticide and fungus showed synergistic effects on mosquito survival. Fungal infection increased permethrin-induced mortality rates in wild An. gambiae s.s. mosquitoes and reciprocally, exposure to permethrin increased subsequent fungal-induced mortality rates in both colonies. Simultaneous co-exposure induced the highest mortality; up to 70.3+/-2% for a combined Beauveria and permethrin exposure within a time range of one gonotrophic cycle (4 days. CONCLUSIONS/SIGNIFICANCE: Combining fungi and permethrin induced a higher impact on mosquito survival than the use of these control agents alone. The observed synergism in efficacy shows the potential for integrated fungus-insecticide control measures to dramatically reduce malaria transmission and enable control at more moderate levels of coverage even in areas where insecticide resistance has rendered pyrethroids essentially ineffective.
An acetylcholinesterase (AChE) biosensor with enhanced solvent resistance based on chitosan for the detection of pesticides.
Warner, John; Andreescu, Silvana
Solvent tolerance of immobilized enzymes is important for many biosensing and biotechnological applications. In this paper we report an acetylcholinesterase (AChE) biosensor based on chitosan that exhibits high solvent resistance and enables sensitive detection of pesticides in presence of a high content of organic solvents. The solvent effect was established comparatively for the enzyme immobilized in chitosan and covalently cross-linked with glutaraldehyde. The activity of the immobilized AChE was dependent on the immobilization method and solvent type. The enzyme entrapped in chitosan fully conserved its activity in up to 25% methanol, 15% acetonitrile and 100% cyclohexane while the enzyme cross-linked with glutaraldehyde gradually lost its activity starting at 5% acetonitrile and methanol, and showed variable levels in cyclohexane. The detection limits of the biosensor for paraoxon were: 7.5 nM in 25% methanol, 100 nM in 15% acetonitrile and 2.5 μM in 100% cyclohexane. This study demonstrates that chitosan provides an excellent immobilization environment for AChE biosensors designed to operate in environments containing high amounts of organic solvents. It also highlights the effect of the immobilization material and solvent type on enzyme stability. These findings can enable future selection of the immobilization matrix and solvent type for the development of organic phase enzyme based systems.
"Monitoring of Insecticide Resistance in Anopheles Sacharovi (Favre, 1903 in Borderline of Iran, Armenia, Naxcivan and Turkey, 2001"
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Sh Salari Lak
Full Text Available Malaria has recently been resurged in some parts of Iran which is bordered with Armenia, Naxcivan and Turkey. An attempt was made to asses the current status of insecticide resistance in the main malaria vector , An.sacharovi. Adult engorged mosquitoes were collected from dwellings during the seasonal activity of the vector, which is synchronized in summer 2001. Mosquitoes were subjected to the diagnostic dose of insecticides based on WHO method. Results showed that this species is still resistant to DDT, tolerant to dieldrin but susceptible to other insecticides such as, bendiocarb, propoxur, malathion, fenitothion, deltamethrin, permethrin, cyfluthrin, lambdacyhalothrin, and etofenprox with low frequency of tolerant gene in some population to some above mentioned insecticides.
High Insecticides Resistance in Culex pipiens (Diptera: Culicidae from Tehran, Capital of Iran
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Yaser Salim-Abadi
Full Text Available Background: During recent years transmission of Dirofilaria immitis (dog heart worm by Culex pipiens and West Nile virus have been reported from Iran. The present study was preformed for evaluating the susceptibility status of Cx. pipiens collected from capital city of Tehran, Iran.Methods: Four Insecticides including: DDT 4%, Lambdacyhalothrin 0.05%, Deltamethrin 0.05% and Cyfluthrin 0.15 % according to WHO standard methods were used for evaluating the susceptibility status of Cx. pipiens from Tehran moreover For comparison susceptibility status a Laboratory strain also was used. Bioassay data were analyzed using Probit program. The lethal time for 50% and 90% mortality (LT50 and LT90 values were calculated from regression line.Results: The susceptibility status of lab strain of Cx. pipiens revealed that it is susceptible to Lambdacyhalothrin, Deltamethrin, Cyfluthrin and resistant to DDT. Moreover cyfluthrin with LT50=36 seconds and DDT with LT50=3005 seconds had the least and most LT50s. Field population was resistance to all tested insecticides and DDT yielded no mortality.Conclusion: Highly resistance level against all WHO recommended imagicides were detected in field populations. We suggest more biochemical and molecular investigations to detect resistance mechanisms in the field population for further decision of vector control.
Evidence of carbamate resistance in urban populations of Anopheles gambiae s.s. mosquitoes resistant to DDT and deltamethrin insecticides in Lagos, South-Western Nigeria
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Oduola Adedayo O
Full Text Available Abstract Background Resistance monitoring is essential in ensuring the success of insecticide based vector control programmes. This study was carried out to assess the susceptibility status of urban populations of Anopheles gambiae to carbamate insecticide being considered for vector control in mosquito populations previously reported to be resistant to DDT and permethrin. Methods Two – three day old adult female Anopheles mosquitoes reared from larval collections in 11 study sites from Local Government Areas of Lagos were exposed to test papers impregnated with DDT 4%, deltamethrin 0.05% and propoxur 0.1% insecticides. Additional tests were carried out to determine the susceptibility status of the Anopheles gambiae population to bendiocarb insecticide. Members of the A. gambiae complex, the molecular forms, were identified by PCR assays. The involvement of metabolic enzymes in carbamate resistance was assessed using Piperonyl butoxide (PBO synergist assays. The presence of kdr-w/e and ace-1R point mutations responsible for DDT-pyrethroid and carbamate resistance mechanisms was also investigated by PCR. Results Propoxur resistance was found in 10 out of the 11 study sites. Resistance to three classes of insecticides was observed in five urban localities. Mortality rates in mosquitoes exposed to deltamethrin and propoxur did not show any significant difference (P > 0.05 but was significantly higher (P A. gambiae s.s (M form. The kdr -w point mutation at allelic frequencies between 45%-77% was identified as one of the resistant mechanisms responsible for DDT and pyrethroid resistance. Ace-1R point mutation was absent in the carbamate resistant population. However, the possible involvement of metabolic resistance was confirmed by synergistic assays conducted. Conclusion Evidence of carbamate resistance in A. gambiae populations already harbouring resistance to DDT and permethrin is a clear indication that calls for the implementation of
Insecticide resistance in Aedes aegypti populations from Ceará, Brazil
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Goulart Marilia OF
Full Text Available Abstract Background Organophosphates and pyrethroids are used widely in Brazil to control Aedes aegypti, the main vector of dengue viruses, under the auspices of the National Programme for Dengue Control. Resistance to these insecticides is widespread throughout Brazil. In Ceará the vector is present in 98% of districts and resistance to temephos has been reported previously. Here we measure resistance to temephos and the pyrethroid cypermethrin in three populations from Ceará and use biochemical and molecular assays to characterise resistance mechanisms. Results Resistance to temephos varied widely across the three studied populations, with resistance ratios (RR95 of 7.2, 30 and 192.7 in Juazeiro do Norte, Barbalha and Crato respectively. The high levels of resistance detected in Barbalha and Crato (RR95 ≥ 30 imply a reduction of temephos efficacy, and indeed in simulated field tests reduced effectiveness was observed for the Barbalha population. Two populations (Crato and Barbalha were also resistant to cypermethrin, whilst Juazeiro do Norte showed only an altered susceptibility. The Ile1011Met kdr mutation was detected in all three populations and Val1016Ile in Crato and Juazeiro do Norte. 1011Met was significantly associated with resistance to cypermethrin in the Crato population. Biochemical tests showed that only the activity of esterases and GSTs, among the tested detoxification enzymes, was altered in these populations when compared with the Rockefeller strain. Conclusions Our results demonstrate that two A. aegypti populations from Ceará are under strong selection pressure by temephos, compromising the field effectiveness of this organophosphate. Our results also provide evidence that the process of reducing resistance to this larvicide in the field is difficult and slow and may require more than seven years for reversal. In addition, we show resistance to cypermethrin in two of the three populations studied, and for the first time
Amplification of a cytochrome P450 gene is associated with resistance to neonicotinoid insecticides in the aphid Myzus persicae.
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Alin M Puinean
Full Text Available The aphid Myzus persicae is a globally significant crop pest that has evolved high levels of resistance to almost all classes of insecticide. To date, the neonicotinoids, an economically important class of insecticides that target nicotinic acetylcholine receptors (nAChRs, have remained an effective control measure; however, recent reports of resistance in M. persicae represent a threat to the long-term efficacy of this chemical class. In this study, the mechanisms underlying resistance to the neonicotinoid insecticides were investigated using biological, biochemical, and genomic approaches. Bioassays on a resistant M. persicae clone (5191A suggested that P450-mediated detoxification plays a primary role in resistance, although additional mechanism(s may also contribute. Microarray analysis, using an array populated with probes corresponding to all known detoxification genes in M. persicae, revealed constitutive over-expression (22-fold of a single P450 gene (CYP6CY3; and quantitative PCR showed that the over-expression is due, at least in part, to gene amplification. This is the first report of a P450 gene amplification event associated with insecticide resistance in an agriculturally important insect pest. The microarray analysis also showed over-expression of several gene sequences that encode cuticular proteins (2-16-fold, and artificial feeding assays and in vivo penetration assays using radiolabeled insecticide provided direct evidence of a role for reduced cuticular penetration in neonicotinoid resistance. Conversely, receptor radioligand binding studies and nucleotide sequencing of nAChR subunit genes suggest that target-site changes are unlikely to contribute to resistance to neonicotinoid insecticides in M. persicae.
Comparing Host Plant Resistance, Engineered Resistance, and Insecticide Treatment for Control of Colorado Potato Beetle and Potato Leafhopper in Potatoes
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Gerald M. Ghidiu
Full Text Available The Colorado potato beetle, Leptinotarsa decemlineata (Say Order Coleoptera and the potato leafhopper, Empoasca fabae (Harris Order Homoptera, are the major insect pests of potato in eastern North America. In two years of field trials, we compared the effectiveness of three pest management options for the control of Colorado potato beetle and potato leafhopper: natural host plant resistance (glandular trichomes, engineered resistance (Bacillus thuringiensis [Bt] Berliner cry3A gene and a susceptible potato cultivar (Superior with an at-planting application of the insecticide thiamethoxam. Similar and acceptable control of the Colorado potato beetle larvae was obtained with the Bt-cry3A lines and the thiamethoxam treated "Superior" variety. The glandular trichome cultivar had significantly less Colorado potato beetle damage than did the untreated "Superior" in 2004, although damage was significantly greater than in the Bt-cry3A lines and the insecticide-treated potatoes for both years, and was the only treatment that consistently had very little potato leafhopper damage. These data demonstrate that although each type of host plant resistance mechanism (Bt-cry3A or glandular trichomes was as effective as the chemical control against one of the insects, neither provides adequate resistance to both Colorado potato beetle and potato leaf hopper.
Additional selection for insecticide resistance in urban malaria vectors: DDT resistance in Anopheles arabiensis from Bobo-Dioulasso, Burkina Faso.
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Christopher M Jones
Full Text Available In the city of Bobo-Dioulasso in Burkina Faso, Anopheles arabiensis has superseded Anopheles gambiae s.s. as the major malaria vector and the larvae are found in highly polluted habitats normally considered unsuitable for Anopheles mosquitoes. Here we show that An. gambiae s.l. adults emerging from a highly polluted site in the city centre (Dioulassoba have a high prevalence of DDT resistance (percentage mortality after exposure to diagnostic dose=65.8% in the dry season and 70.4% in the rainy season, respectively. An investigation into the mechanisms responsible found an unexpectedly high frequency of the 1014S kdr mutation (allele frequency=0.4, which is found at very low frequencies in An. arabiensis in the surrounding rural areas, and an increase in transcript levels of several detoxification genes, notably from the glutathione transferase and cytochrome P450 gene families. A number of ABC transporter genes were also expressed at elevated levels in the DDT resistant An. arabiensis. Unplanned urbanisation provides numerous breeding grounds for mosquitoes. The finding that Anopheles mosquitoes adapted to these urban breeding sites have a high prevalence of insecticide resistance has important implications for our understanding of the selective forces responsible for the rapid spread of insecticide resistant populations of malaria vectors in Africa.
Identification and validation of a gene causing cross-resistance between insecticide classes in Anopheles gambiae from Ghana.
Mitchell, Sara N; Stevenson, Bradley J; Müller, Pie; Wilding, Craig S; Egyir-Yawson, Alexander; Field, Stuart G; Hemingway, Janet; Paine, Mark J I; Ranson, Hilary; Donnelly, Martin James
In the last decade there have been marked reductions in malaria incidence in sub-Saharan Africa. Sustaining these reductions will rely upon insecticides to control the mosquito malaria vectors. We report that in the primary African malaria vector, Anopheles gambiae sensu stricto, a single enzyme, CYP6M2, confers resistance to two classes of insecticide. This is unique evidence in a disease vector of cross-resistance associated with a single metabolic gene that simultaneously reduces the efficacy of two of the four classes of insecticide routinely used for malaria control. The gene-expression profile of a highly DDT-resistant population of A. gambiae s.s. from Ghana was characterized using a unique whole-genome microarray. A number of genes were significantly overexpressed compared with two susceptible West African colonies, including genes from metabolic families previously linked to insecticide resistance. One of the most significantly overexpressed probe groups (false-discovery rate-adjusted P metabolize both type I and type II pyrethroids in recombinant protein assays. Using in vitro assays we show that recombinant CYP6M2 is also capable of metabolizing the organochlorine insecticide DDT in the presence of solubilizing factor sodium cholate.
Impact of insecticide resistance on the field control of Aedes aegypti in the State of São Paulo
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Maria de Lourdes da Graça Macoris
Full Text Available Introduction The need to control dengue transmission by means of insecticides has led to the development of resistance to most of the products used worldwide against mosquitoes. In the State of São Paulo, the Superintendência de Controle de Endemias (SUCEN has annually monitored the susceptibility of Aedes aegypti to insecticides since 1996; since 1999, surveys were conducted in collaboration with the National Network of Laboratories (MoReNAa Network and were coordinated by the Ministry of Health. In this study, in addition to the biological characterization of insecticide resistance in the laboratory, the impact of resistance on field control was evaluated for vector populations that showed resistance in laboratory assays. Methods Field efficacy tests with larvicides and adulticides were performed over a 13-year period, using World Health Organization protocols. Results Data from the field tests showed a reduction in the residual effect of temephos on populations with a resistance ratio of 3. For adults, field control was less effective in populations characterized as resistant in laboratory qualitative assays, and this was confirmed using qualitative assays and field evaluation. Conclusions Our results indicated that management of resistance development needs to be adopted when insect populations show reduced susceptibility. The use of insecticides is a self-limiting tool that needs to be applied cautiously, and dengue control requires more sustainable strategies.
Rhodnius prolixus supergene families of enzymes potentially associated with insecticide resistance.
Schama, Renata; Pedrini, Nicolás; Juárez, M Patricia; Nelson, David R; Torres, André Q; Valle, Denise; Mesquita, Rafael D
Chagas disease or American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite, Trypanosoma cruzi. Once known as an endemic health problem of poor rural populations in Latin American countries, it has now spread worldwide. The parasite is transmitted by triatomine bugs, of which Rhodnius prolixus (Hemiptera, Reduviidae, Triatominae) is one of the vectors and a model organism. This species occurs mainly in Central and South American countries where the disease is endemic. Disease prevention focuses on vector control programs that, in general, rely intensely on insecticide use. However, the massive use of chemical insecticides can lead to resistance. One of the major mechanisms is known as metabolic resistance that is associated with an increase in the expression or activity of detoxification genes. Three of the enzyme families that are involved in this process - carboxylesterases (CCE), glutathione s-transferases (GST) and cytochrome P450s (CYP) - are analyzed in the R. prolixus genome. A similar set of detoxification genes to those of the Hemipteran Acyrthosiphon pisum but smaller than in most dipteran species was found in R. prolixus genome. All major CCE classes (43 genes found) are present but the pheromone/hormone processing class had fewer genes than usual. One main expansion was detected on the detoxification/dietary class. The phosphotriesterase family, recently associated with insecticide resistance, was also represented with one gene. One microsomal GST gene was found and the cytosolic GST gene count (14 genes) is extremely low when compared to the other hemipteran species with sequenced genomes. However, this is similar to Apis mellifera, a species known for its deficit in detoxification genes. In R. prolixus 88 CYP genes were found, with representatives in the four clans (CYP2, CYP3, CYP4 and mitochondrial) usually found in insects. R. prolixus seems to have smaller species-specific expansions of CYP genes than
Characterization of the transcriptome of the Asian gypsy moth Lymantria dispar identifies numerous transcripts associated with insecticide resistance.
Cao, ChuanWang; Sun, LiLi; Wen, RongRong; Shang, QingLi; Ma, Ling; Wang, ZhiYing
Although the Asian gypsy moth Lymantria dispar causes extensive forest damage worldwide, little is known regarding the genes involved in its development or response to insecticides. Accordingly, characterization of the transcriptome of L. dispar larvae would promote the development of toxicological methods for its control. RNA-seq analysis of L. dispar larvae messenger RNA (mRNA) generated 62,063 unigenes with N50 of 993 bp, from which 23,975 unique sequences (E-value insecticide targets, or proteins involved in the metabolism of insecticides. Reads per kilobase of unigene length per million mapped reads (RPKM) analysis identified 39 high abundance transcripts, of which 27 exhibited significantly altered expression patterns across the egg, larvae, pupae, male and female adult stages. Our study provides the most comprehensive transcriptomic sequence resource for L. dispar, which will form the basis for future identification of candidate insecticide resistance genes in L. dispar.
Mining genes involved in insecticide resistance of Liposcelis bostrychophila Badonnel by transcriptome and expression profile analysis.
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Wei Dou
Full Text Available BACKGROUND: Recent studies indicate that infestations of psocids pose a new risk for global food security. Among the psocids species, Liposcelis bostrychophila Badonnel has gained recognition in importance because of its parthenogenic reproduction, rapid adaptation, and increased worldwide distribution. To date, the molecular data available for L. bostrychophila is largely limited to genes identified through homology. Also, no transcriptome data relevant to psocids infection is available. METHODOLOGY AND PRINCIPAL FINDINGS: In this study, we generated de novo assembly of L. bostrychophila transcriptome performed through the short read sequencing technology (Illumina. In a single run, we obtained more than 51 million sequencing reads that were assembled into 60,012 unigenes (mean size = 711 bp by Trinity. The transcriptome sequences from different developmental stages of L. bostrychophila including egg, nymph and adult were annotated with non-redundant (Nr protein database, gene ontology (GO, cluster of orthologous groups of proteins (COG, and KEGG orthology (KO. The analysis revealed three major enzyme families involved in insecticide metabolism as differentially expressed in the L. bostrychophila transcriptome. A total of 49 P450-, 31 GST- and 21 CES-specific genes representing the three enzyme families were identified. Besides, 16 transcripts were identified to contain target site sequences of resistance genes. Furthermore, we profiled gene expression patterns upon insecticide (malathion and deltamethrin exposure using the tag-based digital gene expression (DGE method. CONCLUSION: The L. bostrychophila transcriptome and DGE data provide gene expression data that would further our understanding of molecular mechanisms in psocids. In particular, the findings of this investigation will facilitate identification of genes involved in insecticide resistance and designing of new compounds for control of psocids.
Insecticide resistance in Bemisia tabaci Gennadius (Homoptera : Aleyrodidae) and Anopheles gambiae Giles (Diptera : Culicidae) could compromise the sustainability of malaria vector control strategies in West Africa
Insecticides from the organophosphate (OP) and pyrethroid (PY) chemical families, have respectively, been in use for 50 and 30 years in West Africa, mainly against agricultural pests, but also against vectors of human disease. The selection pressure, with practically the same molecules year after year (mainly on cotton), has caused insecticide resistance in pest populations such as Bemisia tabaci, vector of harmful phytoviruses on vegetables. The evolution toward insecticide resistance in mal...
Alsheikh, Adel A; Mohammed, W S; Noureldin, E M; Daffalla, O M; Shrwani, Y A; Hobani, K J; Alsheikh, F A; Alzahrani, M H; Binsaeed, A A
The present study provided information on the susceptibility status of the adult and larvae of Aedes aegypti mosquitoes in Jazan region of Saudi Arabia. Bioassay tests were performed on adults and larvae by using WHO recommended concentrations and test kits. Adults of Ae. aegypti mosquitoes were exposed to test papers impregnated with Lambda-cyhalothrin (0.05%), Cyfluthrin (0.15%), Deltamethrin (0.05%), Permethrin (0.75%), Fenitrothion (1%), Bendiocarb (0.1%) and DDT (4%) insecticides. Ae. aegypti mosquitoes were found to be susceptible only to Cyfluthrin; (mortality rate was 100%), whereas variable resistances were observed from the rest of the other insecticides tested (mortality rates ranged between 93.6 and 17%). Larvae were subjected to different concentrations of Diflubenzuron, Methoprene (IGRs) and Temephos (Organophosphate). Adult emergence inhibition (IE₅₀ & IE₉₅) values for the IGRs and the (LC₅₀ & LC₉₅) for Temephos were determined by log-probit regression analysis. Ae. aegypti larvae were resistant to Temephos (LC₅₀ 61.8-LC₉₅ 35600.1 mg/l) and showed high susceptibility to Methoprene than Diflubenzuron (IE₅₀ 0.49-IE₉₅ 10.9 mg/l) and (IE₅₀ 0.86 and IE₉₅ 93.8 mg/l), respectively. Larvae were more susceptible to Methoprene than Diflubenzuron by 1.8 folds.
Assessment of resistance risk in obliquebanded leafroller (Lepidoptera: Tortricidae) to the reduced-risk insecticides chlorantraniliprole and spinetoram.
Sial, Ashfaq A; Brunner, Jay F
Obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), is a major pest of pome fruit in Washington. The use of broad-spectrum insecticides for decades has led to the development of insecticide resistance in C. rosaceana. Recently registered insecticides with novel modes of action, such as chlorantraniliprole and spinetoram, have provided effective C. rosaceana control, but resistance remains a threat. The risk of insecticide resistance development in a pest can be assessed by artificial selection in the laboratory. Subsequently, this information can be valuable in developing strategies to retain susceptibility in the field. A laboratory population of C. rosaceana was selected after repeated exposure to chlorantraniliprole and spinetoram to determine the risk of resistance evolution. After six generations of selection, 6.58- and 3.64-fold increases in LC50 were recorded for chlorantraniliprole and spinetoram, respectively. The realized heritability (h2) of resistance was estimated as 0.17 for chlorantraniliprole and 0.18 for spinetoram by using threshold trait analysis. The rates of resistance development were compared using the response quotient (Q), which was estimated as 0.11 and 0.07 for chlorantraniliprole and spinetoram, respectively. Projected rates of resistance evolution indicated that if h2 = 0.2 and 80% of the population was killed at each generation, then a 10-fold increase in LC50 would be expected in less than six generations for chlorantraniliprole and 10 generations for spinetoram. These results indicate that the risk of resistance development in C. rosaceana exists to both of these insecticides but that resistance development in C. rosaceana would be slower against spinetoram than chlorantraniliprole.
Insecticide resistance in the dengue vector Aedes aegypti from Martinique: distribution, mechanisms and relations with environmental factors.
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Sébastien Marcombe
Full Text Available Dengue is an important mosquito borne viral disease in Martinique Island (French West Indies. The viruses responsible for dengue are transmitted by Aedes aegypti, an indoor day-biting mosquito. The most effective proven method for disease prevention has been by vector control by various chemical or biological means. Unfortunately insecticide resistance has already been observed on the Island and recently showed to significantly reduce the efficacy of vector control interventions. In this study, we investigated the distribution of resistance and the underlying mechanisms in nine Ae. aegypti populations. Statistical multifactorial approach was used to investigate the correlations between insecticide resistance levels, associated mechanisms and environmental factors characterizing the mosquito populations. Bioassays revealed high levels of resistance to temephos and deltamethrin and susceptibility to Bti in the 9 populations tested. Biochemical assays showed elevated detoxification enzyme activities of monooxygenases, carboxylesterases and glutathione S-tranferases in most of the populations. Molecular screening for common insecticide target-site mutations, revealed the presence of the "knock-down resistance" V1016I Kdr mutation at high frequency (>87%. Real time quantitative RT-PCR showed the potential involvement of several candidate detoxification genes in insecticide resistance. Principal Component Analysis (PCA performed with variables characterizing Ae. aegypti from Martinique permitted to underline potential links existing between resistance distribution and other variables such as agriculture practices, vector control interventions and urbanization. Insecticide resistance is widespread but not homogeneously distributed across Martinique. The influence of environmental and operational factors on the evolution of the resistance and mechanisms are discussed.
Dynamics of Bemisia tabaci biotypes and insecticide resistance in Fujian province in China during 2005–2014
Yao, Feng-Luan; Zheng, Yu; Huang, Xiao-Yan; Ding, Xue-Ling; Zhao, Jian-Wei; Desneux, Nicolas; He, Yu-Xian; Weng, Qi-Yong
The whitefly Bemisia tabaci (Gennadius) is an important agricultural insect pest worldwide. The B and Q biotypes are the two most predominant and devastating biotypes prevalent across China. However, there are few studies regarding the occurrence of the Q biotype in Fujian Province, China, where high insecticide resistance has been reported in the B biotype. Differences in some biological characteristics between the B and Q biotypes, especially insecticide resistance, are considered to affect the outcome of their competition. Extensive surveys in Fujian revealed that the B biotype was predominant during 2005–2014, whereas the Q biotype was first detected in some locations in 2013 and widely detected throughout the province in 2014. Resistance to neonicotinoids (that have been used for more than 10 years) exhibited fluctuations in open fields, but showed a continual increasing trend in protected areas. Resistance to lambda-cyhalothrin, chlorpyrifos, and abamectin exhibited a declining trend. Resistance to novel insecticides, such as nitenpyram, pymetrozine, sulfoxaflor, and cyantraniliprole, in 2014 was generally below a moderate level. A decline in insecticide resistance in the B biotype and the rapid buildup of protected crops under global temperature increase may have promoted the establishment of the Q biotype in Fujian. PMID:28112233
德国小蠊抗药性机理%Advances in mechanisms of insecticide resistance in Blattella germanica
Institute of Scientific and Technical Information of China (English)
德国小蠊(Blattella germanica)是一种重要的室内卫生害虫,化学防治是目前主要的防治手段,但抗药性已逐渐成为制约德国小蠊防治的关键因素.德国小蠊抗药性的产生存在多种机理,本文从行为抗性、表皮穿透性降低、代谢抗性、靶标抗性及微生物降解等方面对德国小蠊抗药性产生机理进行了综述,重点阐述了近年来德国小蠊抗药性机理最新的研究进展.%Blattella germanica (L.) is an important household insect pest, and chemical insecticides are currently the main control means. Insecticide resistance has gradually become a major obstacle to control Blattella germanica. The mechanisms of insecticide resistance are multiple and are reviewed from behavioral resistance, reduction of cuticle penetration, metabolic resistance, target resistance and microbial degradation. In this paper, we concentrate on the research progress of the mechanisms of insecticide resistance in Blattella germanica in recent years.
The insecticide DDT decreases membrane potential and cell input resistance of cultured human liver cells.
Schefczik, K; Buff, K
The resting membrane potential, Em, and the cell input resistance, Rinp, of cultured human Chang liver cells were measured using the single electrode 'double-pulse' current clamp technique, following exposure of the cells to the insecticide DDT (20 microM). In control (unexposed) cells, the mean Em was -24 mV, and the mean Rinp was 30 M omega. Neither parameter was significantly impaired after 1 h of cell exposure to DDT. But after 7 and 48 h, the Em was depolarized by 15 and 25 mV, respectively, in parallel with a decrease of the cell input resistance. The strongly time-delayed effect of DDT on Chang liver cell membranes may indicate a mode of interaction different from excitable membranes.
The effect of engineered disulfide bonds on the stability of Drosophila melanogaster acetylcholinesterase
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Lamouroux Lucille
Full Text Available Background Acetylcholinesterase is irreversibly inhibited by organophosphate and carbamate insecticides allowing its use in biosensors for detection of these insecticides. Drosophila acetylcholinesterase is the most sensitive enzyme known and has been improved by in vitro mutagenesis. However, its stability has to be improved for extensive utilization. Results To create a disulfide bond that could increase the stability of the Drosophila melanogaster acetylcholinesterase, we selected seven positions taking into account first the distance between Cβ of two residues, in which newly introduced cysteines will form the new disulfide bond and second the conservation of the residues in the cholinesterase family. Most disulfide bonds tested did not increase and even decreased the stability of the protein. However, one engineered disulfide bridge, I327C/D375C showed significant stability increase toward denaturation by temperature (170 fold at 50°C, urea, organic solvent and provided resistance to protease degradation. The new disulfide bridge links the N-terminal domain (first 356 aa to the C-terminal domain. The quantities produced by this mutant were the same as in wild-type flies. Conclusion Addition of a disulfide bridge may either stabilize or unstabilize proteins. One bond out of the 7 tested provided significant stabilisation.
Geographic variation in cypermethrin insecticide resistance and morphometry in Spodoptera litura (Fabricius) (Lepidoptera:Noctuidae)
Institute of Scientific and Technical Information of China (English)
Anbalagan Santhosh Kumar; Kathirvelu Baskar; Ajith Johnson; Savarior Vincent
Objective: To find out the most resistant strain of Spodoptera litura (S. litura) from Tamil Nadu, Kerala and Karnataka by synthetic insecticide treatment. Methods:Using leaf disc no-choice method, the insects were tested with different doses for pesticides. The LC50 and LC90 values were calculated by probit analysis. Results:In the insect bioassay, the cypermethrin insecticide showed significantly higher LC50 values of 14.699 g/L and 15.738 g/L against the Tamil Nadu and Kerala S. litura insect cultures respectively. The body length of 2nd, 3rd and 4th instar larvae were significantly higher (P≤0.05) in TTP insect population [(19.2±2.3) mm, (28.05±3.20) mm, (36.1±2.0) mm], when compared with KTK [(18.5±2.7) mm, (23.38±2.00) mm, (31.75±2.70) mm] and control, KBB [(15.65±2.30) mm, (23.65±2.70) mm, (33.2±2.2) mm] populations. The body breadth of 3rd instar larvae was significantly higher (P≤0.05) in TTP insect population (4.9±1.1) mm, when compared with KTK (3.93±0.80) mm and control, KBB (3.65±0.70) mm populations. Conclusions: The present study clearly showed that field collected strains were highly resistant when compared to control. Based on our study, we conclude that reduced use of synthetic pesticides is necessary and IPM is a better way to reduce the development of pesticide resistance among strains of S. litura.
Efficacy of the Olyset Duo net against insecticide-resistant mosquito vectors of malaria.
Ngufor, Corine; N'Guessan, Raphael; Fagbohoun, Josias; Todjinou, Damien; Odjo, Abibath; Malone, David; Ismail, Hanafy; Akogbeto, Martin; Rowland, Mark
Olyset Duo is a new long-lasting insecticidal net treated with permethrin (a pyrethroid) and pyriproxyfen, an insect growth regulator that disrupts the maturation of oocytes in mosquitoes exposed to the net. We tested the Olyset Duo net against pyrethroid-resistant Anopheles gambiae mosquitoes, which transmit malaria parasites, in laboratory bioassays and in a trial in Benin using experimental huts that closely resemble local habitations. Host-seeking mosquitoes that entered to feed were free to contact the occupied nets and were collected the next morning from exit traps. Surviving blood-fed mosquitoes were observed for effects on reproduction. Control nets were treated with pyrethroid only or pyriproxyfen only, and nets were tested unwashed and after 20 standardized washes. The Olyset Duo net showed improved efficacy and wash resistance relative to the pyrethroid-treated net in terms of mosquito mortality and prevention of blood feeding. The production of offspring among surviving blood-fed A. gambiae in the hut trial was reduced by the pyriproxyfen-treated net and the Olyset Duo net both before washing (90 and 71% reduction, respectively) and after washing (38 and 43% reduction, respectively). The degree of reproductive suppression in the hut trial was predicted by laboratory tunnel tests but not by cone bioassays. The overall reduction in reproductive rate of A. gambiae with the Olyset Duo net in the trial was 94% with no washing and 78% after 20 washes. The Olyset Duo net has the potential to provide community control of mosquito populations and reduce malaria transmission in areas of high insecticide resistance.
Cycloxaprid: A novel cis-nitromethylene neonicotinoid insecticide to control imidacloprid-resistant cotton aphid (Aphis gossypii).
Cui, Li; Qi, Haoliang; Yang, Daibin; Yuan, Huizhu; Rui, Changhui
Imidacloprid is a nicotinic acetylcholine receptor (nAChR) agonist with potent insecticidal activity. However, resistance to imidacloprid is a significant threat and has been identified in several pest species. Cycloxaprid with cis-configuration is a novel neonicotinoid insecticide, which shows high activity against imidacloprid-resistant pests. The LC50 of imidacloprid against the resistant Aphis gossypii was 14.33mgL(-1) while it was only 0.70mgL(-1) for the susceptible population, giving a resistance ratio of 20.47. In this imidacloprid-resistant population, a point mutation (R81T) located in the loop D region of the nAChR β1 subunit was found out. But this point mutation did not decrease the activity of cycloxaprid against A. gossypii. The LC50 of cycloxaprid was 1.05 and 1.36mgL(-1) for the imidacloprid-susceptible and imidacloprid-resistant populations, respectively. In addition, cycloxaprid provided better efficacies against resistant A. gossypii than imidacloprid in the fields. Although cycloxaprid was highly toxic to A. gossypii, it showed high selective activity between A. gossypii and its predominant natural enemies, Harmonia axyridis and Chrysoperla sinica. These results demonstrate that cycloxaprid is a promising insecticide against imidacloprid-resistant A. gossypii and suitable for the integrated pest management.
Discovery of genes related to insecticide resistance in Bactrocera dorsalis by functional genomic analysis of a de novo assembled transcriptome.
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Ju-Chun Hsu
Full Text Available Insecticide resistance has recently become a critical concern for control of many insect pest species. Genome sequencing and global quantization of gene expression through analysis of the transcriptome can provide useful information relevant to this challenging problem. The oriental fruit fly, Bactrocera dorsalis, is one of the world's most destructive agricultural pests, and recently it has been used as a target for studies of genetic mechanisms related to insecticide resistance. However, prior to this study, the molecular data available for this species was largely limited to genes identified through homology. To provide a broader pool of gene sequences of potential interest with regard to insecticide resistance, this study uses whole transcriptome analysis developed through de novo assembly of short reads generated by next-generation sequencing (NGS. The transcriptome of B. dorsalis was initially constructed using Illumina's Solexa sequencing technology. Qualified reads were assembled into contigs and potential splicing variants (isotigs. A total of 29,067 isotigs have putative homologues in the non-redundant (nr protein database from NCBI, and 11,073 of these correspond to distinct D. melanogaster proteins in the RefSeq database. Approximately 5,546 isotigs contain coding sequences that are at least 80% complete and appear to represent B. dorsalis genes. We observed a strong correlation between the completeness of the assembled sequences and the expression intensity of the transcripts. The assembled sequences were also used to identify large numbers of genes potentially belonging to families related to insecticide resistance. A total of 90 P450-, 42 GST-and 37 COE-related genes, representing three major enzyme families involved in insecticide metabolism and resistance, were identified. In addition, 36 isotigs were discovered to contain target site sequences related to four classes of resistance genes. Identified sequence motifs were also
A Survey of Insecticide Resistance in Aedes albopictus (Diptera: Culicidae) During a 2014 Dengue Fever Outbreak in Guangzhou, China.
Yiguan, Wang; Xin, Liu; Chengling, Li; Su, Tianyun; Jianchao, Jin; Yuhong, Guo; Dongsheng, Ren; Zhicong, Yang; Qiyong, Liu; Fengxia, Meng
A dengue fever outbreak in Guangzhou, Guangdong Province, China, in 2014 resulted in ∼37,000 cases and five deaths. Insecticides were sprayed to control the vector of this outbreak, Aedes albopictus (Skuse), a species of mosquito. Aedes albopictus specimens collected from Huadu District (HD), Huangpu District (HP), Luogang District (LG), and Nansha District (NS) in Guangzhou were evaluated using WHO-recommended bioassays for both larvae and adult mosquitoes to determine population resistance to deltamethrin, beta-cypermethrin, cypermethrin, permethrin, dichlorvos, temephos, propoxur, and DDT. Compared with a susceptible laboratory strain of Ae. albopictus (S-lab), all populations showed decreased sensitivities to the eight insecticides, with resistance ratios (RRs) ranging from 2.2 to 275. The RRs were 6.8-275 for pyrethroids, 2.2-4.4 for organophosphates, 5.7-9.0 for carbamates, and 5.3-94.3 for organochlorines. For adult mosquitoes, all populations were sensitive to dichlorvos with 100% mortalities. Mosquitoes from HP, LG, and NS were also sensitive to propoxur. But for other tested insecticides, different degrees of resistance (mortality rate ranging from 11.7% to 94.7%) were observed. Among the four field populations, the resistance levels are presented as follows in descending order: HP > HD > NS > LG. The levels among insecticides classes were pyrethroids > organochlorines > carbamates > organophosphates.
Insect cytochromes P450: diversity, insecticide resistance and tolerance to plant toxins.
Scott, J G; Liu, N; Wen, Z
In the last decade, studies of individual insect P450s have blossomed. This new information has furthered our understanding of P450 diversity, insecticide resistance and tolerance to plant toxins. Insect P450s can be adult specific, larval specific or life stage independent. Similarly, insect P450s vary as to the tissues where they are expressed and in their response to inducers. Insect P450s can now be rapidly sequenced using degenerate PCR primers. Given the huge diversity represented by the Class Insecta, this technique will provide vast amounts of new information about insect P450s and the evolution of the P450 gene superfamily. CYP6D1 is responsible for monooxygenase-mediated resistance to pyrethroid insecticides in the house fly. CYP6D1 is ubiquitously expressed in adults with 10-fold higher levels found in the resistant strain compared to susceptible strains. CYP6D1 is on autosome 1 in house fly. The high level of expression found in the resistant strain is due to genes on autosomes 1 and 2. Whether or not the different CYP6D1 alleles found in resistant and susceptible strains have any role in resistance remains to be elucidated. The CYP6B gene subfamily is involved in the metabolism of host plant toxins (i.e. furanocoumarins). CYP6B gene transcripts in two Papilio (swallowtail) species have been shown to be induced by host plant toxins and in turn to metabolize these toxins. CYP6B P450s play a critical role in allowing Papilio to adapt to furanocoumarin-containing host plants. Similarities in structural and promoter regions of the CYP6B genes suggest that they are derived from a common ancestral gene. Although the P450 monooxygenases of insects are important for the metabolism of hormones and phermones, no individual P450 has yet been shown to metabolize an endogenous compound. Advances in this area are critical because they will provide important new information about insect physiology, biochemistry and development.
Modeling evolution of resistance by Maruca vitrata (Lepidoptera: Crambidae) to transgenic insecticidal cowpea in Africa.
Onstad, D W; Kang, J; Ba, N M; Tamò, M; Jackai, L; Dabire, C; Pittendrigh, B R
We created a detailed model of the Maruca vitrata (F.) and cowpea [Vigna unguiculata (L.) Walp] system to study the possible evolution of resistance by the insect to transgenic insecticidal cowpea, which is under development. We focused on population dynamics and genetics in a region of west Africa. We simulated single-toxin and pyramided (two-toxin) cowpea and emphasized conservative, worst-case scenarios in our analysis. The results indicate that as long as a pyramided, transgenic cowpea can be developed, seed saving by farmers and reliance on natural refuge are not major problems for resistance management. Furthermore, it is possible that one or both toxins in the pyramid may not need to be high dose for evolution to be delayed significantly (>20 yr or 80 generations for resistance to become a concern if transgenic cowpea is deployed in areas where M. vitrata is endemic). If efforts are made to deploy transgenic cowpea only into the regions where M. vitrata is not endemic, then there is little to no concern with resistance emerging in the M. vitrata population.
Assessment of insecticide resistance of Lobesia botrana (Lepidoptera: Tortricidae) in Emilia-Romagna region.
Civolani, Stefano; Boselli, Mauro; Butturini, Alda; Chicca, Milvia; Fano, Elisa Anna; Cassanelli, Stefano
The European grapevine moth, Lobesia botrana (Denis & Schiffermüller) (Lepidoptera: Tortricidae), is the key pest of vineyard, Vitis vinifera L. In Italy, failures in field chemical pest control have been recently reported. The susceptibility to insecticides indoxacarb, methoxyfenozide, and emamectin benzoate was then evaluated in a L. botrana population collected from a vineyard in Emilia-Romagna (northeastern Italy) where pest management programs achieved unsatisfactory results. The field trial showed that the indoxacarb efficacy toward L. botrana was very low in the two timings of application (7.9 and -1.5%) in comparison with untreated control, while the efficacy of methoxyfenozide (76.1%) and emamectin benzoate (88.8%) was high. The decreased efficacy of indoxacarb was also supported by the results of the laboratory bioassay on neonate L. botrana larvae, in which the resistance ratio was 72-fold in comparison with that of the susceptible strain.
Tissue distribution of human acetylcholinesterase and butyrylcholinesterase messenger RNA
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Jbilo, O.; Barteles, C.F.; Chatonnet, A.; Toutant, J.P.; Lockridge, O.
Tissue distribution of human acetyicholinesterase and butyryicholinesterase messenger RNA. 1 Cholinesterase inhibitors occur naturally in the calabar bean (eserine), green potatoes (solanine), insect-resistant crab apples, the coca plant (cocaine) and snake venom (fasciculin). There are also synthetic cholinesterase inhibitors, for example man-made insecticides. These inhibitors inactivate acetyicholinesterase and butyrylcholinesterase as well as other targets. From a study of the tissue distribution of acetylcholinesterase and butyrylcholinesterase mRNA by Northern blot analysis, we have found the highest levels of butyrylcholinesterase mRNA in the liver and lungs, tissues known as the principal detoxication sites of the human body. These results indicate that butyrylcholinesterase may be a first line of defense against poisons that are eaten or inhaled.
Spinosad and the tomato borer Tuta absoluta: a bioinsecticide, an invasive pest threat, and high insecticide resistance.
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Mateus R Campos
Full Text Available The introduction of an agricultural pest species into a new environment is a potential threat to agroecosystems of the invaded area. The phytosanitary concern is even greater if the introduced pest's phenotype expresses traits that will impair the management of that species. The invasive tomato borer, Tuta absoluta (Meyrick (Lepidoptera: Gelechiidae, is one such species and the characterization of the insecticide resistance prevailing in the area of origin is important to guide management efforts in new areas of introduction. The spinosad is one the main insecticides currently used in Brazil for control of the tomato borer; Brazil is the likely source of the introduction of the tomato borer into Europe. For this reason, spinosad resistance in Brazilian populations of this species was characterized. Spinosad resistance has been reported in Brazilian field populations of this pest species, and one resistant population that was used in this study was subjected to an additional seven generations of selection for spinosad resistance reaching levels over 180,000-fold. Inheritance studies indicated that spinosad resistance is monogenic, incompletely recessive and autosomal with high heritability (h(2 = 0.71. Spinosad resistance was unstable without selection pressure with a negative rate of change in the resistance level ( = -0.51 indicating an associated adaptive cost. Esterases and cytochrome P450-dependent monooxygenases titration decreased with spinosad selection, indicating that these detoxification enzymes are not the underlying resistance mechanism. Furthermore, the cross-resistance spectrum was restricted to the insecticide spinetoram, another spinosyn, suggesting that altered target site may be the mechanism involved. Therefore, the suspension of spinosyn use against the tomato borer would be a useful component in spinosad resistance management for this species. Spinosad use against this species in introduced areas should be carefully
Distribution of Voltage-Gated Sodium Channel (Nav) Alleles among the Aedes aegypti Populations In Central Java Province and Its Association with Resistance to Pyrethroid Insecticides
Sayono Sayono; Anggie Puspa Nur Hidayati; Sukmal Fahri; Didik Sumanto; Edi Dharmana; Suharyo Hadisaputro; Puji Budi Setia Asih; Din Syafruddin
The emergence of insecticide resistant Aedes aegypti mosquitoes has hampered dengue control efforts. WHO susceptibility tests, using several pyrethroid compounds, were conducted on Ae. aegypti larvae that were collected and raised to adulthood from Semarang, Surakarta, Kudus and Jepara in Java. The AaNa V gene fragment encompassing kdr polymorphic sites from both susceptible and resistant mosquitoes was amplified, and polymorphisms were associated with the resistant phenotype. The insecticide...
The infectivity of the entomopathogenic fungus Beauveria bassiana to insecticide-resistant and susceptible Anopheles arabiensis mosquitoes at two different temperatures
Kikankie, C.K.; Brooke, B.D.; Knols, B.G.J.; Koekemoer, L.L.; Farenhorst, M.; Hunt, R.H.; Thomas, M.B.; Coetzee, M.
BACKGROUND: Control of the major African malaria vector species continues to rely extensively on the application of residual insecticides through indoor house spraying or bed net impregnation. Insecticide resistance is undermining the sustainability of these control strategies. Alternatives to the c
Differential expression of glutathione s-transferase enzyme in different life stages of various insecticide-resistant strains of Anopheles stephensi: A malaria vector
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D. Sanil
Full Text Available Background & objectives: Interest in insect glutathione s-transferases (GSTs has primarily focused on their role in insecticide resistance. These play an important role in biotransformation and detoxification of many different xenobiotic and endogenous substances including insecticides. The GST activity among 10 laboratory selected insecticide resistant and susceptible/control strains of Anopheles stephensi was compared using the substrates 1-chloro-2,4-dinitrobenzene (CDNB. The difference in the GST activities of different life stages of diverse insecticide resistant strains was compared and presented. Methods: About 100 larvae, pupae, adult males, adult females and eggs (100 μg in total weight were collected and used for the experiment. The extracts were prepared from each of the insecticide-resistant strains and control. Protein contents of the enzyme homogenate and GST activities were determined. Results: Deltamethrin and cyfluthrin-resistant strains of An. stephensi showed significantly higher GST activity. Larvae and pupae of DDT-resistant strain showed peak GST activity followed by the propoxur-resistant strain. On contrary, the GST activity was found in reduced quantity in alphamethrin, bifenthrin, carbofuran and chloropyrifos resistant strains. Adults of either sexes showed higher GST activity in mosquito strain resistant to organophosphate group of insecticides namely, temephos and chloropyrifos. Interpretation & conclusion: The GST activity was closely associated with almost all of the insecticides used in the study, strengthening the fact that one of the mechanisms associated with resistance includes an increase of GST activity. This comparative data on GST activity in An. stephensi can be useful database to identify possible underlying mechanisms governing insecticide-resistance by GSTs.
The role of the Aedes aegypti Epsilon glutathione transferases in conferring resistance to DDT and pyrethroid insecticides.
Lumjuan, Nongkran; Rajatileka, Shavanthi; Changsom, Donch; Wicheer, Jureeporn; Leelapat, Posri; Prapanthadara, La-aied; Somboon, Pradya; Lycett, Gareth; Ranson, Hilary
The Epsilon glutathione transferase (GST) class in the dengue vector Aedes aegypti consists of eight sequentially arranged genes spanning 53,645 bp on super contig 1.291, which maps to chromosome 2. One Epsilon GST, GSTE2, has previously been implicated in conferring resistance to DDT. The amino acid sequence of GSTE2 in an insecticide susceptible and a DDT resistant strain differs at five residues two of which occur in the putative DDT binding site. Characterization of the respective recombinant enzymes revealed that both variants have comparable DDT dehydrochlorinase activity although the isoform from the resistant strain has higher affinity for the insecticide. GSTe2 and two additional Epsilon GST genes, GSTe5 and GSTe7, are expressed at elevated levels in the resistant population and the recombinant homodimer GSTE5-5 also exhibits low levels of DDT dehydrochlorinase activity. Partial silencing of either GSTe7 or GSTe2 by RNA interference resulted in an increased susceptibility to the pyrethroid, deltamethrin suggesting that these GST enzymes may also play a role in resistance to pyrethroid insecticides.
Acetylcholinesterases from the Disease Vectors Aedes aegypti and Anopheles gambiae: Functional Characterization and Comparisons with Vertebrate Orthologues.
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Cecilia Engdahl
Full Text Available Mosquitoes of the Anopheles (An. and Aedes (Ae. genus are principal vectors of human diseases including malaria, dengue and yellow fever. Insecticide-based vector control is an established and important way of preventing transmission of such infections. Currently used insecticides can efficiently control mosquito populations, but there are growing concerns about emerging resistance, off-target toxicity and their ability to alter ecosystems. A potential target for the development of insecticides with reduced off-target toxicity is the cholinergic enzyme acetylcholinesterase (AChE. Herein, we report cloning, baculoviral expression and functional characterization of the wild-type AChE genes (ace-1 from An. gambiae and Ae. aegypti, including a naturally occurring insecticide-resistant (G119S mutant of An. gambiae. Using enzymatic digestion and liquid chromatography-tandem mass spectrometry we found that the secreted proteins were post-translationally modified. The Michaelis-Menten constants and turnover numbers of the mosquito enzymes were lower than those of the orthologous AChEs from Mus musculus and Homo sapiens. We also found that the G119S substitution reduced the turnover rate of substrates and the potency of selected covalent inhibitors. Furthermore, non-covalent inhibitors were less sensitive to the G119S substitution and differentiate the mosquito enzymes from corresponding vertebrate enzymes. Our findings indicate that it may be possible to develop selective non-covalent inhibitors that effectively target both the wild-type and insecticide resistant mutants of mosquito AChE.
Acetylcholinesterases from the Disease Vectors Aedes aegypti and Anopheles gambiae: Functional Characterization and Comparisons with Vertebrate Orthologues.
Engdahl, Cecilia; Knutsson, Sofie; Fredriksson, Sten-Åke; Linusson, Anna; Bucht, Göran; Ekström, Fredrik
Mosquitoes of the Anopheles (An.) and Aedes (Ae.) genus are principal vectors of human diseases including malaria, dengue and yellow fever. Insecticide-based vector control is an established and important way of preventing transmission of such infections. Currently used insecticides can efficiently control mosquito populations, but there are growing concerns about emerging resistance, off-target toxicity and their ability to alter ecosystems. A potential target for the development of insecticides with reduced off-target toxicity is the cholinergic enzyme acetylcholinesterase (AChE). Herein, we report cloning, baculoviral expression and functional characterization of the wild-type AChE genes (ace-1) from An. gambiae and Ae. aegypti, including a naturally occurring insecticide-resistant (G119S) mutant of An. gambiae. Using enzymatic digestion and liquid chromatography-tandem mass spectrometry we found that the secreted proteins were post-translationally modified. The Michaelis-Menten constants and turnover numbers of the mosquito enzymes were lower than those of the orthologous AChEs from Mus musculus and Homo sapiens. We also found that the G119S substitution reduced the turnover rate of substrates and the potency of selected covalent inhibitors. Furthermore, non-covalent inhibitors were less sensitive to the G119S substitution and differentiate the mosquito enzymes from corresponding vertebrate enzymes. Our findings indicate that it may be possible to develop selective non-covalent inhibitors that effectively target both the wild-type and insecticide resistant mutants of mosquito AChE.
Time-of-day specific changes in metabolic detoxification and insecticide resistance in the malaria mosquito Anopheles gambiae.
Balmert, Nathaniel J; Rund, Samuel S C; Ghazi, John P; Zhou, Peng; Duffield, Giles E
Mosquitoes exhibit ∼24 h rhythms in physiology and behavior, regulated by the cooperative action of an endogenous circadian clock and the environmental light:dark cycle. Here, we characterize diel (observed under light:dark conditions) time-of-day changes in metabolic detoxification and resistance to insecticide challenge in Anopheles gambiae mosquitoes. A better understanding of mosquito chronobiology will yield insights into developing novel control strategies for this important disease vector. We have previously identified >2000 rhythmically expressed An. gambiae genes. These include metabolic detoxification enzymes peaking at various times throughout the day. Especially interesting was the identification of rhythmic genes encoding enzymes capable of pyrethroid and/or DDT metabolism (CYP6M2, CYP6P3, CYP6Z1, and GSTE2). We hypothesized that these temporal changes in gene expression would confer time-of-day specific changes in metabolic detoxification and responses to insecticide challenge. An. gambiae mosquitoes (adult female Pimperena and Mali-NIH strains) were tested by gene expression analysis for diel rhythms in key genes associated with insecticidal resistance. Biochemical assays for total GST, esterase, and oxidase enzymatic activities were undertaken on time-specific mosquito head and body protein lysates. To determine for rhythmic susceptibility to insecticides by survivorship, mosquitoes were exposed to DDT or deltamethrin across the diel cycle. We report the occurrence of temporal changes in GST activity in samples extracted from the body and head with a single peak at late-night to dawn, but no rhythms were detected in oxidase or esterase activity. The Pimperena strain was found to be resistant to insecticidal challenge, and subsequent genomic analysis revealed the presence of the resistance-conferring kdr mutation. We observed diel rhythmicity in key insecticide detoxification genes in the Mali-NIH strain, with peak phases as previously reported in
Adaptation and evaluation of the bottle assay for monitoring insecticide resistance in disease vector mosquitoes in the Peruvian Amazon
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Brogdon William G
Full Text Available Abstract Background The purpose of this study was to establish whether the "bottle assay", a tool for monitoring insecticide resistance in mosquitoes, can complement and augment the capabilities of the established WHO assay, particularly in resource-poor, logistically challenging environments. Methods Laboratory reared Aedes aegypti and field collected Anopheles darlingi and Anopheles albimanus were used to assess the suitability of locally sourced solvents and formulated insecticides for use with the bottle assay. Using these adapted protocols, the ability of the bottle assay and the WHO assay to discriminate between deltamethrin-resistant Anopheles albimanus populations was compared. The diagnostic dose of deltamethrin that would identify resistance in currently susceptible populations of An. darlingi and Ae. aegypti was defined. The robustness of the bottle assay during a surveillance exercise in the Amazon was assessed. Results The bottle assay (using technical or formulated material and the WHO assay were equally able to differentiate deltamethrin-resistant and susceptible An. albimanus populations. A diagnostic dose of 10 μg a.i./bottle was identified as the most sensitive discriminating dose for characterizing resistance in An. darlingi and Ae. aegypti. Treated bottles, prepared using locally sourced solvents and insecticide formulations, can be stored for > 14 days and used three times. Bottles can be stored and transported under local conditions and field-assays can be completed in a single evening. Conclusion The flexible and portable nature of the bottle assay and the ready availability of its components make it a potentially robust and useful tool for monitoring insecticide resistance and efficacy in remote areas that require minimal cost tools.
Exploring the molecular basis of insecticide resistance in the dengue vector Aedes aegypti: a case study in Martinique Island (French West Indies
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Yébakima André
Full Text Available Abstract Background The yellow fever mosquito Aedes aegypti is a major vector of dengue and hemorrhagic fevers, causing up to 100 million dengue infections every year. As there is still no medicine and efficient vaccine available, vector control largely based on insecticide treatments remains the only method to reduce dengue virus transmission. Unfortunately, vector control programs are facing operational challenges with mosquitoes becoming resistant to commonly used insecticides. Resistance of Ae. aegypti to chemical insecticides has been reported worldwide and the underlying molecular mechanisms, including the identification of enzymes involved in insecticide detoxification are not completely understood. Results The present paper investigates the molecular basis of insecticide resistance in a population of Ae. aegypti collected in Martinique (French West Indies. Bioassays with insecticides on adults and larvae revealed high levels of resistance to organophosphate and pyrethroid insecticides. Molecular screening for common insecticide target-site mutations showed a high frequency (71% of the sodium channel 'knock down resistance' (kdr mutation. Exposing mosquitoes to detoxification enzymes inhibitors prior to bioassays induced a significant increased susceptibility of mosquitoes to insecticides, revealing the presence of metabolic-based resistance mechanisms. This trend was biochemically confirmed by significant elevated activities of cytochrome P450 monooxygenases, glutathione S-transferases and carboxylesterases at both larval and adult stages. Utilization of the microarray Aedes Detox Chip containing probes for all members of detoxification and other insecticide resistance-related enzymes revealed the significant constitutive over-transcription of multiple detoxification genes at both larval and adult stages. The over-transcription of detoxification genes in the resistant strain was confirmed by using real-time quantitative RT
Allelic Variation of Cytochrome P450s Drives Resistance to Bednet Insecticides in a Major Malaria Vector.
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Sulaiman S Ibrahim
Full Text Available Scale up of Long Lasting Insecticide Nets (LLINs has massively contributed to reduce malaria mortality across Africa. However, resistance to pyrethroid insecticides in malaria vectors threatens its continued effectiveness. Deciphering the detailed molecular basis of such resistance and designing diagnostic tools is critical to implement suitable resistance management strategies. Here, we demonstrated that allelic variation in two cytochrome P450 genes is the most important driver of pyrethroid resistance in the major African malaria vector Anopheles funestus and detected key mutations controlling this resistance. An Africa-wide polymorphism analysis of the duplicated genes CYP6P9a and CYP6P9b revealed that both genes are directionally selected with alleles segregating according to resistance phenotypes. Modelling and docking simulations predicted that resistant alleles were better metabolizers of pyrethroids than susceptible alleles. Metabolism assays performed with recombinant enzymes of various alleles confirmed that alleles from resistant mosquitoes had significantly higher activities toward pyrethroids. Additionally, transgenic expression in Drosophila showed that flies expressing resistant alleles of both genes were significantly more resistant to pyrethroids compared with those expressing the susceptible alleles, indicating that allelic variation is the key resistance mechanism. Furthermore, site-directed mutagenesis and functional analyses demonstrated that three amino acid changes (Val109Ile, Asp335Glu and Asn384Ser from the resistant allele of CYP6P9b were key pyrethroid resistance mutations inducing high metabolic efficiency. The detection of these first DNA markers of metabolic resistance to pyrethroids allows the design of DNA-based diagnostic tools to detect and track resistance associated with bednets scale up, which will improve the design of evidence-based resistance management strategies.
First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions
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Akogbéto Martin
Full Text Available Abstract Background Insecticide-resistant mosquitoes are compromising the ability of current mosquito control tools to control malaria vectors. A proposed new approach for mosquito control is to use entomopathogenic fungi. These fungi have been shown to be lethal to both insecticide-susceptible and insecticide-resistant mosquitoes under laboratory conditions. The goal of this study was to see whether entomopathogenic fungi could be used to infect insecticide-resistant malaria vectors under field conditions, and to see whether the virulence and viability of the fungal conidia decreased after exposure to ambient African field conditions. Methods This study used the fungus Beauveria bassiana to infect the insecticide-resistant malaria vector Anopheles gambiae s.s (Diptera: Culicidae VKPER laboratory colony strain. Fungal conidia were applied to polyester netting and kept under West African field conditions for varying periods of time. The virulence of the fungal-treated netting was tested 1, 3 and 5 days after net application by exposing An. gambiae s.s. VKPER mosquitoes in WHO cone bioassays carried out under field conditions. In addition, the viability of B. bassiana conidia was measured after up to 20 days exposure to field conditions. Results The results show that B. bassiana infection caused significantly increased mortality with the daily risk of dying being increased by 2.5× for the fungus-exposed mosquitoes compared to the control mosquitoes. However, the virulence of the B. bassiana conidia decreased with increasing time spent exposed to the field conditions, the older the treatment on the net, the lower the fungus-induced mortality rate. This is likely to be due to the climate because laboratory trials found no such decline within the same trial time period. Conidial viability also decreased with increasing exposure to the net and natural abiotic environmental conditions. After 20 days field exposure the conidial viability was 30%, but
First report of the infection of insecticide-resistant malaria vector mosquitoes with an entomopathogenic fungus under field conditions
Background Insecticide-resistant mosquitoes are compromising the ability of current mosquito control tools to control malaria vectors. A proposed new approach for mosquito control is to use entomopathogenic fungi. These fungi have been shown to be lethal to both insecticide-susceptible and insecticide-resistant mosquitoes under laboratory conditions. The goal of this study was to see whether entomopathogenic fungi could be used to infect insecticide-resistant malaria vectors under field conditions, and to see whether the virulence and viability of the fungal conidia decreased after exposure to ambient African field conditions. Methods This study used the fungus Beauveria bassiana to infect the insecticide-resistant malaria vector Anopheles gambiae s.s (Diptera: Culicidae) VKPER laboratory colony strain. Fungal conidia were applied to polyester netting and kept under West African field conditions for varying periods of time. The virulence of the fungal-treated netting was tested 1, 3 and 5 days after net application by exposing An. gambiae s.s. VKPER mosquitoes in WHO cone bioassays carried out under field conditions. In addition, the viability of B. bassiana conidia was measured after up to 20 days exposure to field conditions. Results The results show that B. bassiana infection caused significantly increased mortality with the daily risk of dying being increased by 2.5× for the fungus-exposed mosquitoes compared to the control mosquitoes. However, the virulence of the B. bassiana conidia decreased with increasing time spent exposed to the field conditions, the older the treatment on the net, the lower the fungus-induced mortality rate. This is likely to be due to the climate because laboratory trials found no such decline within the same trial time period. Conidial viability also decreased with increasing exposure to the net and natural abiotic environmental conditions. After 20 days field exposure the conidial viability was 30%, but the viability of control
Insecticide resistance may enhance the response to a host-plant volatile kairomone for the codling moth, Cydia pomonella (L.)
Sauphanor, Benoît; Franck, Pierre; Lasnier, Thérèse; Toubon, Jean-François; Beslay, Dominique; Boivin, Thomas; Bouvier, Jean-Charles; Renou, Michel
The behavioral and electroantennographic responses of Cydia pomonella (L.) to the ripe pear volatile ethyl (2 E,4 Z)-2,4-decadienoate (Et- E, Z-DD), were compared in insecticide-susceptible and -resistant populations originating from southern France. A dose-response relationship to this kairomonal attractant was established for antennal activity and did not reveal differences between susceptible and resistant strains. Conversely, males of the laboratory strains expressing metabolic [cytochrome P450-dependent mixed-function oxidases (mfo)] or physiological (kdr-type mutation of the sodium-channel gene) resistance mechanisms exhibited a significantly higher response to Et- E, Z-DD than those of the susceptible strain in a wind tunnel experiment. No response of the females to this kairomone could be obtained in our wind-tunnel conditions. In apple orchards, mfo-resistant male moths were captured at significantly higher rates in kairomone-baited traps than in traps baited with the sex pheromone of C. pomonella. Such a differential phenomenon was not verified for the kdr-resistant insects, which exhibited a similar response to both the sex pheromone and the kairomonal attractant in apple orchards. Considering the widespread distribution of metabolic resistance in European populations of C. pomonella and the enhanced behavioral response to Et- E, Z-DD in resistant moths, the development of control measures based on this kairomonal compound would be of great interest for the management of insecticide resistance in this species.
Insecticide resistance and genetic variability in natural populations of Aedes (Stegomyia aegypti (Diptera: Culicidae from Colombia
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Oscar A. Aguirre-Obando
Full Text Available Mosquito control prevails as the most efficient method to protect humans from the dengue virus, despite recent efforts to find a vaccine for this disease. We evaluated insecticide resistance and genetic variability in natural populations of Aedes aegypti (Linnaeus, 1762 from Colombia. This is the first Colombian study examining kdr mutations and population structure. Bioassays with larvae of three mosquito populations (Armenia, Calarcá and Montenegro were performed according to the World Health Organization (WHO guidelines, using Temephos. For the analysis of the Val1016Ile mutation and genetic diversity, we sampled recently-emerged adults from four mosquito populations (Armenia, Calarcá, Montenegro and Barcelona. Following the WHO protocol, bioassays implemented with larvae showed resistance to Temephos in mosquito populations from Armenia (77% ± 2 and Calarcá (62% ± 14, and an incipient altered susceptibility at Montenegro (88% ± 8. The RR95 of mosquito populations ranged from 3.7 (Montenegro to 6.0 (Calarca. The Val1016Ile mutation analysis of 107 genotyped samples indicates that 94% of the specimens were homozygous for the wild allele (1016Val and 6% were heterozygous (Val1016Ile. The 1016Ile allele was not found in Barcelona. Genetic variability analysis found three mitochondrial lineages with low genetic diversity and gene flow. In comparison with haplotypes from the American continent, those from this study suggest connections with Mexican and North American populations. These results confirm that a continuous monitoring and managing program of A. aegypti resistance in the state of Quindío is required.
Field evaluation of pyriproxyfen and spinosad mixture for the control of insecticide resistant Aedes aegypti in Martinique (French West Indies
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Darriet Frédéric
Full Text Available Abstract Background The resistance of Ae. aegypti to insecticides is already widespread and continues to develop. It represents a serious problem for programmes aimed at the control and prevention of dengue in tropical countries. In the light of this problem measures to control Ae. aegypti are being orientated towards how best to use existing insecticides, notably by combining those that have different modes of action. Results In this study we evaluated the operational efficiency of a mixture composed of pyriproxyfen (an insect growth regulator and spinosad (a biopesticide against a population of Ae. aegypti from Martinique resistant to pyrethroid and organophosphate insecticides. The first step consisted of evaluating the efficacy of pyriproxyfen and spinosad when used alone, or in combination, against Ae. aegypti larvae under simulated conditions. The results showed that the mixture of pyriproxyfen+spinosad remained active for at least 8 months, compared with 3 months for spinosad alone, and 5 months for pyriproxyfen alone. In a second step in containers experiencing natural conditions, pyriproxyfen and spinosad, maintained the rate of adult emergence at 20% for 3 weeks and 3.5 months, respectively. Following the same criteria of evaluation, the mixture pyriproxyfen+spinosad remained effective for 4.5 months, showing that the combination of the two larvicides with different modes of action acted to increase the residual activity of the treatment. Conclusion The mixture of pyriproxyfen and spinosad kills larvae and pupae giving it a broader range of action than either insecticide. This mixture could preserve the utility of both insecticides in public health programs.
If you see one, have you seen them all?: Community-wide effects of insecticide cross-resistance in zooplankton populations near and far from agriculture.
Bendis, Randall J; Relyea, Rick A
The worldwide use of pesticides has led to increases in agricultural yields by reducing crop losses. However, increased pesticide use has resulted in pesticide-resistant pest species and recent studies have discovered pesticide-resistance in non-target species living close to farms. Such increased tolerance not only affects the species, but can alter the entire food web. Given that some species can evolve not only resistance to a single pesticide, but also cross-resistance to other pesticides that share the same mode of action, one would predict that cross-resistance to pesticides would also have effects on the entire community and affect community stability. To address this hypothesis, we conducted an outdoor mesocosm experiment comprised of 200 identical aquatic communities with phytoplankton, periphyton, and leopard frog (Lithobates pipiens) tadpoles. To these communities, we added one of four Daphnia pulex populations that we previously discovered were either resistant or sensitive to the insecticide of chlorpyrifos as a result of living close to or far from agriculture, respectively. We then exposed the communities to either no insecticide or three different concentrations of AChE-inhibiting insecticides (chlorpyrifos, malathion or carbaryl) or sodium channel-inhibiting insecticides (permethrin or cypermethrin). We discovered that communities containing sensitive Daphnia pulex experienced phytoplankton blooms and subsequent cascades through all trophic groups including amphibians at moderate to high concentrations of all five insecticides. However, communities containing resistant D. pulex were buffered from these effects at low to moderate concentrations of all AChE-inhibiting insecticides, but were not buffered against the pyrethroid insecticides. These data suggest that a simple change in the population-level resistance of zooplankton to a single insecticide can have widespread consequences for community stability and that the effects can be extrapolated
Insecticide susceptible/resistance status in Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus (Diptera : Culicidae) in Thailand during 2003-2005
Jirakanjanakit, N.; Rongnoparut, P.; Saengtharatip, S.; T Chareonviriyaphap; Duchn, S.; Bellec, Christian; Yoksan, S
Susceptibility baselines and diagnostic doses of the technical grade insecticides deltamethrin, permethrin, fenitrothion, and propoxur were established based on Aedes aegypti (L.), Bora (French Polynesia), a reference susceptible strain. Field-collected Aedes mosquitoes from each part of Thailand were subjected to bioassay for their susceptibility to the diagnostic doses of each insecticide. Almost all Ae. aegypti collected were incipient resistant or resistant to deltamethrin and permethrin,...
Evolutionary changes in gene expression, coding sequence and copy-number at the Cyp6g1 locus contribute to resistance to multiple insecticides in Drosophila.
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Thomas W R Harrop
Full Text Available Widespread use of insecticides has led to insecticide resistance in many populations of insects. In some populations, resistance has evolved to multiple pesticides. In Drosophila melanogaster, resistance to multiple classes of insecticide is due to the overexpression of a single cytochrome P450 gene, Cyp6g1. Overexpression of Cyp6g1 appears to have evolved in parallel in Drosophila simulans, a sibling species of D. melanogaster, where it is also associated with insecticide resistance. However, it is not known whether the ability of the CYP6G1 enzyme to provide resistance to multiple insecticides evolved recently in D. melanogaster or if this function is present in all Drosophila species. Here we show that duplication of the Cyp6g1 gene occurred at least four times during the evolution of different Drosophila species, and the ability of CYP6G1 to confer resistance to multiple insecticides exists in D. melanogaster and D. simulans but not in Drosophila willistoni or Drosophila virilis. In D. virilis, which has multiple copies of Cyp6g1, one copy confers resistance to DDT and another to nitenpyram, suggesting that the divergence of protein sequence between copies subsequent to the duplication affected the activity of the enzyme. All orthologs tested conferred resistance to one or more insecticides, suggesting that CYP6G1 had the capacity to provide resistance to anthropogenic chemicals before they existed. Finally, we show that expression of Cyp6g1 in the Malpighian tubules, which contributes to DDT resistance in D. melanogaster, is specific to the D. melanogaster-D. simulans lineage. Our results suggest that a combination of gene duplication, regulatory changes and protein coding changes has taken place at the Cyp6g1 locus during evolution and this locus may play a role in providing resistance to different environmental toxins in different Drosophila species.
Obtaining High Pest-resistant Tobacco Plants Carrying B.t. insecticidal Gene
Institute of Scientific and Technical Information of China (English)
To increase the expression level of CryIA(c) gene in transgenic plants, a plant expression vector pBinMoBc carrying the CryIA(c) gene under control of chimeric OM promoter and Ω factor was constructed. As a control, pBinoBc carrying the CryIA(c) gene with the CaMV 35S promoter was also constructed. The vectors were transferred into tobacco plants respectively via Agrobacterium-mediated transformation. ELISA assay showed that the expression level of the CryIA(c) gene in pBinMoBc transgenic tobacco plants was 2.44-times that in pBinoBc transgenic tobacco plants, and it could be up to 0.255% of total soluble proteins. Bioassay showed that pBinMoBc transgenic tobacco plants had more notable insecticidal effect than pBinoBc transgenic tobacco plants. The above results showed that the chimeric OM promoter was a stronger promoter than CaMV 35S promoter that was widely used in plant genetic engineering, and this is very useful in pest-resistant plant genetic engineering.
Surveillance, insecticide resistance and control of an invasive Aedes aegypti (Diptera: Culicidae) population in California.
Cornel, Anthony J; Holeman, Jodi; Nieman, Catelyn C; Lee, Yoosook; Smith, Charles; Amorino, Mark; Brisco, Katherine K; Barrera, Roberto; Lanzaro, Gregory C; Mulligan Iii, F Stephen
The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS) traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B), when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV) trials using a new formulation of deltamethrin (DeltaGard®) demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath) after a single truck mounted aerial ULV application in residential areas.
Surveillance, insecticide resistance and control of an invasive Aedes aegypti (Diptera: Culicidae) population in California
Cornel, Anthony J.; Holeman, Jodi; Nieman, Catelyn C.; Lee, Yoosook; Smith, Charles; Amorino, Mark; Brisco, Katherine K.; Barrera, Roberto; Lanzaro, Gregory C.; Mulligan III, F. Stephen
The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS) traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B), when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV) trials using a new formulation of deltamethrin (DeltaGard®) demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath) after a single truck mounted aerial ULV application in residential areas. PMID:27158450
Multiple Insecticide Resistance in the Malaria Vector Anopheles funestus from Northern Cameroon Is Mediated by Metabolic Resistance Alongside Potential Target Site Insensitivity Mutations
Menze, Benjamin D.; Riveron, Jacob M.; Ibrahim, Sulaiman S.; Irving, Helen; Antonio-Nkondjio, Christophe; Awono-Ambene, Parfait H.; Wondji, Charles S.
Background Despite the recent progress in establishing the patterns of insecticide resistance in the major malaria vector Anopheles funestus, Central African populations of this species remain largely uncharacterised. To bridge this important gap and facilitate the implementation of suitable control strategies against this vector, we characterised the resistance patterns of An. funestus population from northern Cameroon. Methods and Findings Collection of indoor-resting female mosquitoes in Gounougou (northern Cameroon) in 2012 and 2015 revealed a predominance of An. funestus during dry season. WHO bioassays performed using F1 An. funestus revealed that the population was multiple resistant to several insecticide classes including pyrethroids (permethrin, deltamethrin, lambda-cyhalothrin and etofenprox), carbamates (bendiocarb) and organochlorines (DDT and dieldrin). However, a full susceptibility was observed against the organophosphate malathion. Bioassays performed with 2015 collection revealed that resistance against pyrethroids and DDT is increasing. PBO synergist assays revealed a significant recovery of susceptibility for all pyrethroids but less for DDT. Analysis of the polymorphism of a portion of the voltage-gated sodium channel gene (VGSC) revealed the absence of the L1014F/S kdr mutation but identified 3 novel amino acid changes I877L, V881L and A1007S. However, no association was established between VGSC polymorphism and pyrethroid/DDT resistance. The DDT resistant 119F-GSTe2 allele (52%) and the dieldrin resistant 296S-RDL allele (45%) were detected in Gounougou. Temporal analysis between 2006, 2012 and 2015 collections revealed that the 119F-GSTe2 allele was relatively stable whereas a significant decrease is observed for 296S-RDL allele. Conclusion This multiple resistance coupled with the temporal increased in resistance intensity highlights the need to take urgent measures to prolong the efficacy of current insecticide-based interventions against
3-Oxoisoxazole-2(3H)-carboxamides and isoxazol-3-yl carbamates: Resistance-breaking acetylcholinesterase inhibitors targeting the malaria mosquito, Anopheles gambiae
Verma, Astha; Wong, Dawn M.; Islam, Rafique; Tong, Fan; Ghavami, Maryam; Mutunga, James M.; Slebodnick, Carla; Li, Jianyong; Viayna, Elisabet; Lam, Polo C.-H.; Totrov, Maxim M.; Bloomquist, Jeffrey R.; Carlier, Paul R.
To identify potential selective and resistance-breaking mosquitocides against the African malaria vector Anopheles gambiae, we investigated the acetylcholinesterase (AChE) inhibitory and mosquitocidal properties of isoxazol-3-yl dimethylcarbamates (15), and the corresponding 3-oxoisoxazole-2(3H)-dimethylcarboxamide isomers (14). In both series, compounds were found with excellent contact toxicity to wild-type susceptible (G3) strain and multiply resistant (Akron) strain mosquitoes that carry the G119S resistance mutation of AChE. Compounds possessing good to excellent toxicity to Akron strain mosquitoes inhibit the G119S mutant of An. gambiae AChE (AgAChE) with ki values at least 10- to 600-fold higher than that of propoxur, a compound that does not kill Akron mosquitoes at the highest concentration tested. On average, inactivation of WT AgAChE by dimethylcarboxamides 14 was 10-20 fold faster than that of the corresponding isoxazol-3-yl dimethylcarbamates 15. X-ray crystallography of dimethylcarboxamide 14d provided insight into that reactivity, a finding that may explain the inhibitory power of structurally-related inhibitors of hormone-sensitive lipase. Finally, human/An. gambiae AChE inhibition selectivities of these compounds were low, suggesting the need for additional structural modification. PMID:25684426
Detoxifying enzyme studies on cotton leafhopper, Amrasca biguttula biguttula (Ishida, resistance to neonicotinoid insecticides in field populations in Karnataka, India
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Halappa Banakar
Full Text Available The cotton leafhopper (Amrasca biguttula biguttula Ishida is considered to be an alarming insect pest causing both quantitative and qualitative loss in cotton. In situ bioassay studies were done and the role of detoxifying enzymes in conferring resistance to neonicotinoid groups of insecticides in low (MUD, medium (DVG, high (HVR and very high (GLB pesticide usage areas of Karnataka were determined. Bioassay studies showed that imidacloprid, thiamethoxam, acetamiprid, thiacloprid and clothianidin registered varying levels of resistance for all the locations studied. The resistance ratio was high in imidacloprid (3.35, 8.57, 9.15 and 12.27 fold respectively and the lowest in dinoferuran (1.86, 5.13, 6.71 and 9.88 fold respectively. Furthermore, the enzyme activity ratio (glutathione-S-transferase was relatively greater, and corresponded to the higher LC50 values of neonicotinoids for very high, high, medium and low pesticide usage areas. Our study suggested that the higher activity of the detoxifying enzyme in the resistance population of cotton leafhopper apparently has a significant role in endowing resistance to neonicotinoid groups of insecticides. However, this study recommends using neonicotinoids in cotton growing areas with caution.
[The effect of insecticide resistance on the demographic parameters of 3 strains of Culex quinquefasciatus (Diptera: Culicidae) under laboratory conditions].
Suárez, S; Montada, D; Fuentes, O; Castex, M; Leyva, M
The life tables of 3 strains of Culex quinquefasciatus were studied under laboratory conditions: Slab, susceptible to reference; Old Havana, treated with cypermethrin until its fourth generation; and Cotorro, from the field. It was found that the different levels of resistance to organophosphate insecticides and pyrethroids present in the Cotorro and Old Havana strains did not influence either on the duration of the period of development of the immature stages or in the sexual proportion of the emerged adults, but they had a favorable and directly proportional effect on the survival and longevity of the adults. However, they exerted a negative and inversely proportional influence on the reproduction and population growth of these strains. Useful data for the use and management of insecticides within the strategies of control of Culex quinquefasciatus, an important vector of lymphatic filariasis, are provided.
"Insecticide Resistance /Susceptibility Monitoring in Anopheles pulcherrimus (Diptera: Culicidae in Ghasreghand District, Sistan and Baluchistan Province, Iran"
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AH Zahirnia
Full Text Available Two organochlorine, one organophosphate, two carbamate and two pyrethroid insecticides have been studied for their comparative study against fieldcollected An.pulcherrimus. The trail was conducted in Ghasreghand district, Sistan and Baluchistan province, Southeastern Iran using WHO impregnated papers at the diagnostic dose. Results revealed that this species exhibit resistant to 0.4% dieldrin (mortality 86 ± 2.07. Dose response regression line from interval exposure times to 0.4% dieldrin showed that LT50 and LT90 was 14 and 76 minutes, respectively. The efficacles of other insecticides such as 4% DDT, 5% malathion, 0.1% bendiocarb, 0.1% propoxur, 0.25% permethrin and 0.1% lambdacyhalothrin were maximum when mosquitoes exposed 1 hour at diagnostic dose followed by 24 hour recovery period.
Resistance of Aedes aegypti from the state of São Paulo, Brazil, to organophosphates insecticides
Macoris Maria de Lourdes G; Andrighetti Maria Teresa M; Takaku Luiz; Glasser Carmen M; Garbeloto Vanessa C; Bracco José Eduardo
Since the reintroduction of Aedes aegypti in the state of São Paulo, in the middle of the 1980-decade, organophosphate insecticides are being used to control the dengue vector. In 1996, an annual program for monitoring the susceptibility of Ae. aegypti to the insecticides was implemented. Some of the results of this monitoring program are presented. Ae. aegypti populations from ten localities have been submitted to bioassays with the diagnostic dose of temephos and fenitrothion. Only two (Mar...
Distribution of Voltage-Gated Sodium Channel (Nav) Alleles among the Aedes aegypti Populations In Central Java Province and Its Association with Resistance to Pyrethroid Insecticides.
Sayono, Sayono; Hidayati, Anggie Puspa Nur; Fahri, Sukmal; Sumanto, Didik; Dharmana, Edi; Hadisaputro, Suharyo; Asih, Puji Budi Setia; Syafruddin, Din
The emergence of insecticide resistant Aedes aegypti mosquitoes has hampered dengue control efforts. WHO susceptibility tests, using several pyrethroid compounds, were conducted on Ae. aegypti larvae that were collected and raised to adulthood from Semarang, Surakarta, Kudus and Jepara in Java. The AaNaV gene fragment encompassing kdr polymorphic sites from both susceptible and resistant mosquitoes was amplified, and polymorphisms were associated with the resistant phenotype. The insecticide susceptibility tests demonstrated Ae, aegypti resistance to the pyrethroids, with mortality rates ranging from 1.6%-15.2%. Three non-synonymous polymorphisms (S989P, V1016G and F1534C) and one synonymous polymorphism (codon 982) were detected in the AaNaV gene. Eight AaNaV alleles were observed in specimens from Central Java. Allele 3 (SGF) and allele 7 (PGF) represent the most common alleles found and demonstrated strong associations with resistance to pyrethroids (OR = 2.75, CI: 0.97-7.8 and OR = 7.37, CI: 2.4-22.5, respectively). This is the first report of 8 Ae. aegypti AaNaV alleles, and it indicates the development of resistance in Ae. aegypti in response to pyrethroid insecticide-based selective pressure. These findings strongly suggest the need for an appropriate integrated use of insecticides in the region. The 989P, 1016G and 1534C polymorphisms in the AaNaV gene are potentially valuable molecular markers for pyrethroid insecticide resistance monitoring.
Distribution of Voltage-Gated Sodium Channel (Nav Alleles among the Aedes aegypti Populations In Central Java Province and Its Association with Resistance to Pyrethroid Insecticides.
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Sayono Sayono
Full Text Available The emergence of insecticide resistant Aedes aegypti mosquitoes has hampered dengue control efforts. WHO susceptibility tests, using several pyrethroid compounds, were conducted on Ae. aegypti larvae that were collected and raised to adulthood from Semarang, Surakarta, Kudus and Jepara in Java. The AaNaV gene fragment encompassing kdr polymorphic sites from both susceptible and resistant mosquitoes was amplified, and polymorphisms were associated with the resistant phenotype. The insecticide susceptibility tests demonstrated Ae, aegypti resistance to the pyrethroids, with mortality rates ranging from 1.6%-15.2%. Three non-synonymous polymorphisms (S989P, V1016G and F1534C and one synonymous polymorphism (codon 982 were detected in the AaNaV gene. Eight AaNaV alleles were observed in specimens from Central Java. Allele 3 (SGF and allele 7 (PGF represent the most common alleles found and demonstrated strong associations with resistance to pyrethroids (OR = 2.75, CI: 0.97-7.8 and OR = 7.37, CI: 2.4-22.5, respectively. This is the first report of 8 Ae. aegypti AaNaV alleles, and it indicates the development of resistance in Ae. aegypti in response to pyrethroid insecticide-based selective pressure. These findings strongly suggest the need for an appropriate integrated use of insecticides in the region. The 989P, 1016G and 1534C polymorphisms in the AaNaV gene are potentially valuable molecular markers for pyrethroid insecticide resistance monitoring.
Bacillus thuringiensis insecticidal three-domain Cry toxins: mode of action, insect resistance and consequences for crop protection.
Pardo-López, Liliana; Soberón, Mario; Bravo, Alejandra
Bacillus thuringiensis bacteria are insect pathogens that produce different Cry and Cyt toxins to kill their hosts. Here we review the group of three-domain Cry (3d-Cry) toxins. Expression of these 3d-Cry toxins in transgenic crops has contributed to efficient control of insect pests and a reduction in the use of chemical insecticides. The mode of action of 3d-Cry toxins involves sequential interactions with several insect midgut proteins that facilitate the formation of an oligomeric structure and induce its insertion into the membrane, forming a pore that kills midgut cells. We review recent progress in our understanding of the mechanism of action of these Cry toxins and focus our attention on the different mechanisms of resistance that insects have evolved to counter their action, such as mutations in cadherin, APN and ABC transporter genes. Activity of Cry1AMod toxins, which are able to form toxin oligomers in the absence of receptors, against different resistant populations, including those affected in the ABC transporter and the role of dominant negative mutants as antitoxins, supports the hypothesis that toxin oligomerization is a limiting step in the Cry insecticidal activity. Knowledge of the action of 3d-Cry toxin and the resistance mechanisms to these toxins will set the basis for a rational design of novel toxins to overcome insect resistance, extending the useful lifespan of Cry toxins in insect control programs.
De novo sequencing-based transcriptome and digital gene expression analysis reveals insecticide resistance-relevant genes in Propylaea japonica (Thunberg (Coleoptea: Coccinellidae.
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Liang-De Tang
Full Text Available The ladybird Propylaea japonica (Thunberg is one of most important natural enemies of aphids in China. This species is threatened by the extensive use of insecticides but genomics-based information on the molecular mechanisms underlying insecticide resistance is limited. Hence, we analyzed the transcriptome and expression profile data of P. japonica in order to gain a deeper understanding of insecticide resistance in ladybirds. We performed de novo assembly of a transcriptome using Illumina's Solexa sequencing technology and short reads. A total of 27,243,552 reads were generated. These were assembled into 81,458 contigs and 33,647 unigenes (6,862 clusters and 26,785 singletons. Of the unigenes, 23,965 (71.22% have putative homologues in the non-redundant (nr protein database from NCBI, using BLASTX, with a cut-off E-value of 10(-5. We examined COG, GO and KEGG annotations to better understand the functions of these unigenes. Digital gene expression (DGE libraries showed differences in gene expression profiles between two insecticide resistant strains. When compared with an insecticide susceptible profile, a total of 4,692 genes were significantly up- or down- regulated in a moderately resistant strain. Among these genes, 125 putative insecticide resistance genes were identified. To confirm the DGE results, 16 selected genes were validated using quantitative real time PCR (qRT-PCR. This study is the first to report genetic information on P. japonica and has greatly enriched the sequence data for ladybirds. The large number of gene sequences produced from the transcriptome and DGE sequencing will greatly improve our understanding of this important insect, at the molecular level, and could contribute to the in-depth research into insecticide resistance mechanisms.
Dynamics of knockdown pyrethroid insecticide resistance alleles in a field population of Anopheles gambiae s.s. in southwestern Nigeria
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T.S. Awolola, A.O. Oduola, I.O. Oyewole, J.B. Obansa, C.N. Amajoh
Full Text Available Background & objectives: Pyrethroid insecticide resistance in the malaria vector Anopheles gambiaeGiles is mainly associated with reduced target site sensitivity arising from a single point mutation inthe sodium channel gene, often referred to as knockdown resistance (kdr. This resistance mechanismis widespread in West Africa and was reported for the first time in Nigeria in 2002. Here we presentchanges in the susceptibility/resistance status of the molecular 'M' and 'S' forms of An. gambiae andthe frequency of the kdr alleles from 2002–05.Methods: Adult anophelines were sampled quarterly inside human dwellings from January 2002 toDecember 2005 and adults reared from wild larvae were identified using morphological keys. Samplesbelonging to the An. gambiae complex were subjected to PCR assays for species identification anddetection of molecular 'M' and 'S' forms. Insecticide susceptibility tests were carried out usingstandard WHO procedures and test kits only on 2–3 days old adult An. gambiae s.s. reared fromlarval collections. The kdr genotypes were determined in both live and dead specimens of An. gambiaes.s. using alleles-specific polymerase chain reaction diagnostic tests.Results: The overall collection showed that the molecular 'S' form was predominant (>60% but theproportions of both forms in the mosquito populations from 2002–05 were not statistically different.Both forms also occurred throughout the period without apparent relationship to wet or dry season.Insecticide susceptibility tests did not show any significant increase in the resistance status recordedfor either Permethrin or DDT from 2002–05, rather, an improvement in the susceptibility status ofthe mosquitoes to these insecticides was observed from 2004–05 relative to the tests performed in2002–03.Conclusion: The proportion of the molecular 'M' and 'S' form of An. gambiae and the kdr frequencieshave not increased significantly from 2002
Pyrosequencing the Bemisia tabaci transcriptome reveals a highly diverse bacterial community and a robust system for insecticide resistance.
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Wen Xie
Full Text Available BACKGROUND: Bemisia tabaci (Gennadius is a phloem-feeding insect poised to become one of the major insect pests in open field and greenhouse production systems throughout the world. The high level of resistance to insecticides is a main factor that hinders continued use of insecticides for suppression of B. tabaci. Despite its prevalence, little is known about B. tabaci at the genome level. To fill this gap, an invasive B. tabaci B biotype was subjected to pyrosequencing-based transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes. METHODOLOGY AND PRINCIPAL FINDINGS: Using Roche 454 pyrosequencing, 857,205 reads containing approximately 340 megabases were obtained from the B. tabaci transcriptome. De novo assembly generated 178,669 unigenes including 30,980 from insects, 17,881 from bacteria, and 129,808 from the nohit. A total of 50,835 (28.45% unigenes showed similarity to the non-redundant database in GenBank with a cut-off E-value of 10-5. Among them, 40,611 unigenes were assigned to one or more GO terms and 6,917 unigenes were assigned to 288 known pathways. De novo metatranscriptome analysis revealed highly diverse bacterial symbionts in B. tabaci, and demonstrated the host-symbiont cooperation in amino acid production. In-depth transcriptome analysis indentified putative molecular markers, and genes potentially involved in insecticide resistance and nutrient digestion. The utility of this transcriptome was validated by a thiamethoxam resistance study, in which annotated cytochrome P450 genes were significantly overexpressed in the resistant B. tabaci in comparison to its susceptible counterparts. CONCLUSIONS: This transcriptome/metatranscriptome analysis sheds light on the molecular understanding of symbiosis and insecticide resistance in an agriculturally important phloem-feeding insect pest, and lays the foundation for future functional genomics research of the
Stable expression and functional characterisation of the diamondback moth ryanodine receptor G4946E variant conferring resistance to diamide insecticides.
Troczka, Bartlomiej J; Williams, Alan J; Williamson, Martin S; Field, Linda M; Lüemmen, Peter; Davies, T G Emyr
Diamides, such as flubendiamide and chlorantraniliprole, belong to a new chemical class of insecticides that act as conformation-sensitive activators of insect ryanodine receptors (RyRs). Both compounds are registered for use against lepidopteran species such as the diamondback moth, Plutella xylostella, a notorious global pest of cruciferous crops. Recently acquired resistance to diamide insecticides in this species is thought to be due to a target-site mutation conferring an amino acid substitution (G4946E), located within the trans-membrane domain of the RyR, though the exact role of this mutation has not yet been fully determined. To address this we have cloned a full-length cDNA encoding the P. xylostella RyR and established clonal Sf9 cell lines stably expressing either the wildtype RyR or the G4946E variant, in order to test the sensitivity to flubendiamide and chlorantraniliprole on the recombinant receptor. We report that the efficacy of both diamides was dramatically reduced in clonal Sf9 cells stably expressing the G4946E modified RyR, providing clear functional evidence that the G4946E RyR mutation impairs diamide insecticide binding.
A review of plant protection against the olive fly (Bactrocera oleae (Rossi, 1790 Gmelin and molecular methods to monitor the insecticide resistance alleles
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Matjaž Hladnik
Full Text Available Olive fly (Bactrocera oleae (Rossi, 1790 Gmelin is one of the most important olive pests worldwide. Most plant protection measures are based on insecticides, especially organophosphates, pyrethroids, and recently a spinosad. Insecticides are used as cover sprays or in more environmentally friendly methods in which insecticides are used in combination with attractants and pheromones as bait sprays or for mass trapping. However, due to negative impacts of insecticides to environment, new plant protection methods are constantly developing with the aim to lower the consumption of insecticides or even to eliminate them by biological control with entomopathogenic organisms, sterile insect technique (SIT, or transgenic method RIDL (release of insects carrying a dominant lethal. However, these methods need to be improved in order to guarantee adequate protection. Alternative methods than those traditionally used are required due to long term usage causing the development of resistance to the insecticides, ultimately lowering their effectiveness. Molecular methods for monitoring the frequencies of resistant alleles and the current status of resistance alleles in olive growing countries are reviewed here.
Relationship between the activities of Glutathione S-transferase and Acetylcholinesterase of Blattella germanica and its resistance%德国小蠊谷胱甘肽S-转移酶和乙酰胆碱酯酶活力与抗药性的关系
Institute of Scientific and Technical Information of China (English)
陈东亚; 褚宏亮; 杨维芳; 孙俊
Objective To understand the relationship between the activities of glutathione S-transferase and acetylcholinesterase of Blattella germanica and its resistance, and then provide scientific evidence for the establishment of resistance detection by biochemistry. Methods The insecticide film was used to identify the resistance of German cockroach to four kinds of insecticides. The enzyme activity was tested by spectrophotometry. Results The resistance ratio of B. germanica to four insecticides was 1.08, 2.35, 7.47, 10.92, respectively. GSTs activity of resistant strain was much higher than that of susceptibility strain, and the difference was very significant. AChE activity of resistant strain was lower than that of susceptibility strain, and the difference was significant. Conclusion B.germanica had high resistance to beta-cypermethrin and deltamethrin, and low resistance to DDVP and propoxur. The increase of GSTs activity could speed up the metabolism of pesticides, leading to the decrease of B. germanica susceptibility. AChE as an orgnaophosphorus and carbamate insecticides target enzyme, the decrease of the activity led to the decline of B. germanica susceptibility. The results indicated that the changes of enzyme activity had the close relationship with the development of resistance.%目的 了解德国小蠊的谷胱甘肽S-转移酶(GSTs)和乙酰胆碱酯酶(ACHE)与抗药性的关系,为探讨德国小蠊抗性机制及建立抗性生化检测方法提供理论依据.方法 采用药膜法测定德国小蠊对4种常用杀虫剂的抗性水平,采用分光光度法测定酶活性.结果 德国小蠊对DDVP、残杀威、溴氰菊酯和高效氯氰菊酯抗性系数分别为1.08、2.35、7.47和10.92.对德国小蠊抗性和敏感品系GSTs、AChE活力比较结果表明,抗性品系GSTs活力相对于敏感品系明显升高,差异有统计学意义(P<0.01),抗性品系AChE活力相对于敏感品系明显下降,差异亦有统计学意义(P<0.01).结论 德�
A whole transcriptomal linkage analysis of gene co-regulation in insecticide resistant house flies, Musca domestica
DEFF Research Database (Denmark)
Li, Ming; Reid, William R; Zhang, Lee;
generated from the de novo transcriptome assembly. A total of 6159 (43%) of the contigs contained coding regions, among which 1316 genes were identified as being co-up-regulated in ALHF in comparison to both aabys and CS. The majority of these up-regulated genes fell within the SCOP categories of metabolism...... recessive markers) and CS (wild type) to gain valuable insights into the gene interaction and complex regulation in insecticide resistance of house flies, Musca domestica. Results Over 56 million reads were used to assemble the adult female M. domestica transcriptome reference and 14488 contigs were...
Larvicidal activities of chinaberry, neem and Bacillus thuringiensis israelensis (Bti to an insecticide resistant population of Anopheles arabiensis from Tolay, Southwest Ethiopia
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Assalif Demissew
Conclusions: Neem, chinaberry and Bti showed potent larvicidal and pupicidal activities. However, in the area, high level of mosquito resistance to pyrethroids and dichloro-diphenyl-tricgloroethane was seen which will pose serious challenge to vector control in the future. Therefore, using integrated approach including these botanical larvicides is warranted to manage insecticide resistance.
The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa
Howard, A.F.V.; N'Guessan, R.; Koenraadt, C.J.M.; Asidi, A.; Farenhorst, M.; Akogbéto, M.; Thomas, M.B.; Knols, B.G.J.; Takken, W.
Background Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show that
The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa
Howard, A.F.V.; N'Guessan, R.; Koenraadt, C.J.M.; Asidi, A.; Farenhorst, M.; Akogbeto, M.; Thomas, M.B.; Knols, B.G.J.; Takken, W.
Background: Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show tha
Agrobacterium tumefaciens-mediated transformation of rice with the spider insecticidal gene conferring resistance to leaffolder and striped stem borer
Institute of Scientific and Technical Information of China (English)
Immature embryos of rice varieties "Xiushui11" and "Chunjiang 11" precultured for 4d were infected and transformed by Agrobacterium tumefaciens strain EHA101/pExT7(containing the spider insecticidal gene).The resistant calli were transferred onto the differentiation medium and plants were regenerated.The transformation frequency reached 56%~72% measured as numbers of Geneticin(G418)-resistant calli produced and 36%~60% measured as numbers of transgenic plants regenerated,respectively.PCR and Southern blot analysis of transgenic plants confirmed that the T-DNA had been integrated into the rice genome.Insect bioassays using T1 transgenic plants indicated that the mortality of the leaffolder(Cnaphalocrasis medinalis)after 7d of leaf feeding reached 38%~61% and the corrected mortality of the striped stem borer(Chilo suppressalis)after 7d of leaf feeding reached 16%~75%.The insect bioassay results demonstrated that the transgenic plants expressing the spider insecticidal protein conferred enhanced resistance to these pests.
Relationship between kdr mutation and resistance to pyrethroid and DDT insecticides in natural populations of Anopheles gambiae.
Reimer, Lisa; Fondjo, Etienne; Patchoké, Salomon; Diallo, Brehima; Lee, Yoosook; Ng, Arash; Ndjemai, Hamadou M; Atangana, Jean; Traore, Sekou F; Lanzaro, Gregory; Cornel, Anthony J
The spread of insecticide resistance genes in Anopheles gambiae Giles sensu stricto threatens to compromise vector-based malaria control programs. Two mutations at the same locus in the voltage-gated sodium channel gene are known to confer knockdown resistance (kdr) to pyrethroids and DDT. Kdr-e involves a leucine-serine substitution, and it was until recently thought to be restricted to East Africa, whereas kdr-w, which involves a leucine-phenylalanine substitution, is associated with resistance in West Africa. In this study, we analyze the frequency and relationship between the kdr genotypes and resistance to type I and type II pyrethroids and DDT by using WHO test kits in both the Forest-M and S molecular forms of An. gambiae in Cameroon. Both kdr-w and kdr-e polymorphisms were found in sympatric An. gambiae, and in many cases in the same mosquito. Kdr-e and kdr-w were detected in both forms, but they were predominant in the S form. Both kdr-e and kdr-w were closely associated with resistance to DDT and weakly associated with resistance to type II pyrethroids. Kdr-w conferred greater resistance to permethrin than kdr-e. We also describe a modified diagnostic designed to detect both resistant alleles simultaneously.
Organophosphorus Insecticide Pharmacokinetics
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Timchalk, Charles
This chapter highlights a number of current and future applications of pharmacokinetics to assess organophosphate (OP) insecticide dosimetry, biological response and risk in humans exposed to these agents. Organophosphates represent a large family of pesticides where insecticidal as well as toxicological mode of action is associated with their ability to target and inhibit acetylcholinesterase (AChE). Pharmacokinetics entails the quantitative integration of physiological and metabolic processes associated with the absorption, distribution, metabolism and excretion (ADME) of drugs and xenobiotics. Pharmacokinetic studies provide important data on the amount of toxicant delivered to a target site as well as species-, age-, gender-specific and dose-dependent differences in biological response. These studies have been conducted with organophosphorus insecticides in multiple species, at various dose levels, and across different routes of exposure to understand their in vivo pharmacokinetics and how they contribute to the observed toxicological response. To access human exposure to organophosphorus insecticides, human pharmacokinetic studies have been conducted and used to develop biological monitoring strategies based on the quantitation of key metabolites in biological fluids. Pharmacokinetic studies with these insecticides are also useful to facilitate extrapolation of dosimetry and biological response from animals to humans and for the assessment of human health risk. In this regard, physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) models are being utilized to assess risk and understand the toxicological implications of known or suspected exposures to various insecticides. In this chapter a number of examples are presented that illustrate the utility and limitation of pharmacokinetic studies to address human health concerns associated with organophosphorus insecticides.
The infectivity of the entomopathogenic fungus Beauveria bassiana to insecticide-resistant and susceptible Anopheles arabiensis mosquitoes at two different temperatures
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Koekemoer Lizette L
Full Text Available Abstract Background Control of the major African malaria vector species continues to rely extensively on the application of residual insecticides through indoor house spraying or bed net impregnation. Insecticide resistance is undermining the sustainability of these control strategies. Alternatives to the currently available conventional chemical insecticides are, therefore, urgently needed. Use of fungal pathogens as biopesticides is one such possibility. However, one of the challenges to the approach is the potential influence of varied environmental conditions and target species that could affect the efficacy of a biological 'active ingredient'. An initial investigation into this was carried out to assess the susceptibility of insecticide-susceptible and resistant laboratory strains and wild-collected Anopheles arabiensis mosquitoes to infection with the fungus Beauveria bassiana under two different laboratory temperature regimes. Methods Insecticide susceptibility to all four classes of insecticides recommended by WHO for vector control was tested on laboratory and wild-caught An. arabiensis, using standard WHO bioassay protocols. Mosquito susceptibility to fungus infection was tested using dry spores of B. bassiana under two temperature regimes (21 ± 1°C or 25 ± 2°C representative of indoor conditions observed in western Kenya. Cox regression analysis was used to assess the effect of fungal infection on mosquito survival and the effect of insecticide resistance status and temperature on mortality rates following fungus infection. Results Survival data showed no relationship between insecticide susceptibility and susceptibility to B. bassiana. All tested colonies showed complete susceptibility to fungal infection despite some showing high resistance levels to chemical insecticides. There was, however, a difference in fungus-induced mortality rates between temperature treatments with virulence significantly higher at 25°C than 21�
Susceptibility profile of Aedes aegypti from Santiago Island, Cabo Verde, to insecticides.
Rocha, Hélio Daniel Ribeiro; Paiva, Marcelo Henrique Santos; Silva, Norma Machado; de Araújo, Ana Paula; Camacho, Denise dos Reis da Rosa de Azevedo; Moura, Aires Januário Fernandes da; Gómez, Lara Ferrero; Ayres, Constância Flávia Junqueira; Santos, Maria Alice Varjal de Melo
In 2009, Cabo Verde diagnosed the first dengue cases, with 21,137 cases reported and Aedes aegypti was identified as the vector. Since the outbreak, chemical insecticides and source reduction were used to control the mosquito population. This study aimed to assess the susceptibility of A. aegypti populations from Santiago, Cabo Verde to insecticides and identify the mechanisms of resistance. Samples of A. aegypti eggs were obtained at two different time periods (2012 and 2014), using ovitraps in different locations in Santiago Island to establish the parental population. F1 larvae were exposed to different concentrations of insecticides (Bacillus thuringiensis var israelensis (Bti), diflubenzuron and temephos) to estimate the lethal concentrations (LC90) and calculate the respective rate of resistance (RR90). Semi-field tests using temephos-ABATE(®) were performed to evaluate the persistence of the product. Bottle tests using female mosquitoes were carried out to determine the susceptibility to the adulticides malathion, cypermethrin and deltamethrin. Biochemical and molecular tests were performed to investigate the presence of metabolic resistance mechanisms, associated with the enzymes glutathione S-transferases (GSTs), esterases and mixed-function oxidases (MFO) and to detect mutations or alterations in the sodium channel and acetylcholinesterase genes. A. aegypti mosquitoes from Santiago exhibited resistance to deltamethrin, cypermethrin (mortalityaegypti population from Santiago is resistant to two major insecticides used for vector control, deltamethrin and temephos. To our knowledge, this is the first report of temephos resistance in an African A. aegypti population. The low level of temephos resistance was maintained from 2012-2014, which suggested the imposition of selective pressure, although it was not possible to identify the resistance mechanisms involved. These data show that the potential failures in the local mosquito control program are not
The Role of Oxidative Stress in the Longevity and Insecticide Resistance Phenotype of the Major Malaria Vectors Anopheles arabiensis and Anopheles funestus.
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Shüné V Oliver
Full Text Available Oxidative stress plays numerous biological roles, both functional and pathological. The role of oxidative stress in various epidemiologically relevant biological traits in Anopheles mosquitoes is not well established. In this study, the effects of oxidative stress on the longevity and insecticide resistance phenotype in the major malaria vector species An. arabiensis and An. funestus were examined. Responses to dietary copper sulphate and hydrogen peroxide were used as proxies for the oxidative stress phenotype by determining the effect of copper on longevity and hydrogen peroxide lethal dose. Glutathione peroxidase and catalase activities were determined colorimetrically. Oxidative burden was quantified as protein carbonyl content. Changes in insecticide resistance phenotype were monitored by WHO bioassay. Insecticide resistant individuals showed an increased capacity for coping with oxidative stress, mediated by increased glutathione peroxidase and catalase activity. This effect was observed in both species, as well as in laboratory strains and F1 individuals derived from wild-caught An. funestus mothers. Phenotypic capacity for coping with oxidative stress was greatest in strains with elevated Cytochrome P450 activity. Synergism of oxidative stress defence enzymes by dietary supplementation with haematin, 3-Amino-1, 2, 4-triazole and Sodium diethyldithiocarbamate significantly increased pyrethroid-induced mortality in An. arabiensis and An. funestus. It is therefore concluded that defence against oxidative stress underlies the augmentation of the insecticide resistance phenotype associated with multiple blood-feeding. This is because multiple blood-feeding ultimately leads to a reduction of oxidative stress in insecticide resistant females, and also reduces the oxidative burden induced by DDT and pyrethroids, by inducing increased glutathione peroxidase activity. This study highlights the importance of oxidative stress in the longevity and
Genome analysis of cytochrome P450s and their expression profiles in insecticide resistant mosquitoes, Culex quinquefasciatus.
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Ting Yang
Full Text Available Here we report a study of the 204 P450 genes in the whole genome sequence of larvae and adult Culex quinquefasciatus mosquitoes. The expression profiles of the P450 genes were compared for susceptible (S-Lab and resistant mosquito populations, two different field populations of mosquitoes (HAmCq and MAmCq, and field parental mosquitoes (HAmCq(G0 and MAmCq(G0 and their permethrin selected offspring (HAmCq(G8 and MAmCq(G6. While the majority of the P450 genes were expressed at a similar level between the field parental strains and their permethrin selected offspring, an up- or down-regulation feature in the P450 gene expression was observed following permethrin selection. Compared to their parental strains and the susceptible S-Lab strain, HAmCq(G8 and MAmCq(G6 were found to up-regulate 11 and 6% of total P450 genes in larvae and 7 and 4% in adults, respectively, while 5 and 11% were down-regulated in larvae and 4 and 2% in adults. Although the majority of these up- and down-regulated P450 genes appeared to be developmentally controlled, a few were either up- or down-regulated in both the larvae and adult stages. Interestingly, a different gene set was found to be up- or down-regulated in the HAmCq(G8 and MAmCq(G6 mosquito populations in response to insecticide selection. Several genes were identified as being up- or down-regulated in either the larvae or adults for both HAmCq(G8 and MAmCq(G6; of these, CYP6AA7 and CYP4C52v1 were up-regulated and CYP6BY3 was down-regulated across the life stages and populations of mosquitoes, suggesting a link with the permethrin selection in these mosquitoes. Taken together, the findings from this study indicate that not only are multiple P450 genes involved in insecticide resistance but up- or down-regulation of P450 genes may also be co-responsible for detoxification of insecticides, insecticide selection, and the homeostatic response of mosquitoes to changes in cellular environment.
Methods of insecticides resistance monitoring of the striped stem borer, Chilo suppressalis%水稻二化螟抗药性监测方法
Institute of Scientific and Technical Information of China (English)
吴敏; 张真真; 高聪芬
Methods of insecticide resistance monitoring, including micro-topical and rice seedling dipping methods, adapted for resistance monitoring in the striped stem borer, are introduced. The topical method is used to bioassay contact insecticides. However, this method does not accurately reflect the activity of insecticides which act after being ingested. The rice seedling dipping technique was therefore established to detect resistance to insecticides that require ingestion, such as diamides and Bt microbial insecticides.%本文首先介绍了二化螟Chilo suppressalis(Walker)抗药性监测的方法:点滴法和稻苗浸渍法.其中点滴法已有标准化的生测规程,其适用于以触杀作用为主的杀虫剂抗性监测,但无法准确反映以胃毒作用为主的杀虫剂的毒力效果,因此,本文新建了以胃毒作用为主的双酰胺类或微生物杀虫剂Bt等的抗性监测方法——稻苗浸渍法.
Association mapping of insecticide resistance in wild Anopheles gambiae populations: major variants identified in a low-linkage disequilbrium genome.
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David Weetman
Full Text Available BACKGROUND: Association studies are a promising way to uncover the genetic basis of complex traits in wild populations. Data on population stratification, linkage disequilibrium and distribution of variant effect-sizes for different trait-types are required to predict study success but are lacking for most taxa. We quantified and investigated the impacts of these key variables in a large-scale association study of a strongly selected trait of medical importance: pyrethroid resistance in the African malaria vector Anopheles gambiae. METHODOLOGY/PRINCIPAL FINDINGS: We genotyped ≈1500 resistance-phenotyped wild mosquitoes from Ghana and Cameroon using a 1536-SNP array enriched for candidate insecticide resistance gene SNPs. Three factors greatly impacted study power. (1 Population stratification, which was attributable to co-occurrence of molecular forms (M and S, and cryptic within-form stratification necessitating both a partitioned analysis and genomic control. (2 All SNPs of substantial effect (odds ratio, OR>2 were rare (minor allele frequency, MAF<0.05. (3 Linkage disequilibrium (LD was very low throughout most of the genome. Nevertheless, locally high LD, consistent with a recent selective sweep, and uniformly high ORs in each subsample facilitated significant direct and indirect detection of the known insecticide target site mutation kdr L1014F (OR≈6; P<10(-6, but with resistance level modified by local haplotypic background. CONCLUSION: Primarily as a result of very low LD in wild A. Gambiae, LD-based association mapping is challenging, but is feasible at least for major effect variants, especially where LD is enhanced by selective sweeps. Such variants will be of greatest importance for predictive diagnostic screening.
Institute of Scientific and Technical Information of China (English)
施明安; 袁建忠; 吴峻; 庄佩君; 唐振华
本文对家蝇抗性和敏感品系中的乙酰胆碱酯酶(AChE)的催化特性进行了研究.抗性品系中AChE水解ATCh和BTCh的Vmax分别为4578.50和1716.08;而敏感品系的Vmax则为1884.75和864.72 nmol/min/mg protein;Vmax的比率(R/S)对ATCh是2.26倍;对BTCh则是1.74倍.AChE的Km值在敏感品系中分别是0.069和0.034;而在抗性品系中则分别是0.156和0.059mmol/L;Km的比率(R/S)对ATCh是2.43倍;对BTCh则是1.98倍.此外,我们还用eserine作为滴定剂测定了AChE的转换数kcat和酶特异性常数kca/Km,抗性品系中的AChE kca值均比敏感品系的要高;而kcat/Km值与此相反.本文着重分析了抗性品系与敏感品系间AChE的催化特性以及对残杀威、灭多威、对氧磷的敏感度差异,研究结果表明抗性品系中的AChE性质有可能发生变化.同时还观察到某些杀虫剂能增强抗性品系AChE的活力,我们认为这种"增强反应"可能与家蝇对有机磷或氨基甲酸酯类杀虫剂的抗性发展有关.%Acetylcholinesterase (AChE) in the susceptible (S) and the resistant (R) strains of housefly (Musca domestica ) was investigated using kinetic analysis. The Vmax values of AChE for hydrolyzing acetylthiocholine (ATCh) and butyrylthiocholine (BTCh) were 4578.50 and 1716.08nmol/min/mg@protein in the R strain, and were 1884.75 and 864.72 nmol/min/mg. protein in the S strain, respectively. The Vmax ratios of R to S enzyme were 2.43 for ATCh and 1.98 for BTCh. The Km values of AChE for ATCh and BTCh were 0. 069 and 0. 034 mmol/L in the S strain, and 0. 156, 0. 059 mmol/L in the R strain, respectively. The Km ratios of R to S enzyme were 2.26 for ATCh and 1.74 for BTCh. The ki ratios of S to R enzyme for three insecticides propoxur, methomyl and paraoxon were 46.04, 4.17 and 2.86, respectively. In addition, kcat and kcat/Km for measuring turnover and catalytic efficiency of AChE were determined using eserine as titrant. The kcat values of AChE from the R strain for both ATCh and
Insecticide resistance status in the whitefly, Bemisia tabaci genetic groups Asia-I, Asia-II-1 and Asia-II-7 on the Indian subcontinent
Naveen, N. C.; Chaubey, Rahul; Kumar, Dinesh; Rebijith, K. B.; Rajagopal, Raman; Subrahmanyam, B.; Subramanian, S.
The present study is a summary of the current level of the insecticide resistance to selected organophosphates, pyrethroids, and neonicotinoids in seven Indian field populations of Bemisia tabaci genetic groups Asia-I, Asia-II-1, and Asia-II-7. Susceptibility of these populations was varied with Asia-II-7 being the most susceptible, while Asia-I and Asia-II-1 populations were showing significant resistance to these insecticides. The variability of the LC50 values was 7x for imidacloprid and thiamethoxam, 5x for monocrotophos and 3x for cypermethrin among the Asia-I, while, they were 7x for cypermethrin, 6x for deltamethrin and 5x for imidacloprid within the Asia-II-1 populations. When compared with the most susceptible, PUSA population (Asia-II-7), a substantial increase in resistant ratios was observed in both the populations of Asia-I and Asia-II-1. Comparative analysis during 2010–13 revealed a decline in susceptibility in Asia-I and Asia-II-1 populations of B. tabaci to the tested organophosphate, pyrethroid, and neonicotinoid insecticides. Evidence of potential control failure was detected using probit analysis estimates for cypermethrin, deltamethrin, monocrotophos and imidacloprid. Our results update resistance status of B. tabaci in India. The implications of insecticide resistance management of B. tabaci on Indian subcontinent are discussed. PMID:28098188
Distribution of Voltage-Gated Sodium Channel (Nav) Alleles among the Aedes aegypti Populations In Central Java Province and Its Association with Resistance to Pyrethroid Insecticides
Sayono, Sayono; Hidayati, Anggie Puspa Nur; Fahri, Sukmal; Sumanto, Didik; Dharmana, Edi; Hadisaputro, Suharyo; Asih, Puji Budi Setia; Syafruddin, Din
The emergence of insecticide resistant Aedes aegypti mosquitoes has hampered dengue control efforts. WHO susceptibility tests, using several pyrethroid compounds, were conducted on Ae. aegypti larvae that were collected and raised to adulthood from Semarang, Surakarta, Kudus and Jepara in Java. The AaNaV gene fragment encompassing kdr polymorphic sites from both susceptible and resistant mosquitoes was amplified, and polymorphisms were associated with the resistant phenotype. The insecticide susceptibility tests demonstrated Ae, aegypti resistance to the pyrethroids, with mortality rates ranging from 1.6%–15.2%. Three non-synonymous polymorphisms (S989P, V1016G and F1534C) and one synonymous polymorphism (codon 982) were detected in the AaNaV gene. Eight AaNaV alleles were observed in specimens from Central Java. Allele 3 (SGF) and allele 7 (PGF) represent the most common alleles found and demonstrated strong associations with resistance to pyrethroids (OR = 2.75, CI: 0.97–7.8 and OR = 7.37, CI: 2.4–22.5, respectively). This is the first report of 8 Ae. aegypti AaNaV alleles, and it indicates the development of resistance in Ae. aegypti in response to pyrethroid insecticide-based selective pressure. These findings strongly suggest the need for an appropriate integrated use of insecticides in the region. The 989P, 1016G and 1534C polymorphisms in the AaNaV gene are potentially valuable molecular markers for pyrethroid insecticide resistance monitoring. PMID:26939002
Mtx toxins synergize Bacillus sphaericus and Cry11Aa against susceptible and insecticide-resistant Culex quinquefasciatus larvae.
Wirth, Margaret C; Yang, Yangkun; Walton, William E; Federici, Brian A; Berry, Colin
Two mosquitocidal toxins (Mtx) of Bacillus sphaericus, which are produced during vegetative growth, were investigated for their potential to increase toxicity and reduce the expression of insecticide resistance through their interactions with other mosquitocidal proteins. Mtx-1 and Mtx-2 were fused with glutathione S-transferase and produced in Escherichia coli, after which lyophilized powders of these fusions were assayed against Culex quinquefasciatus larvae. Both Mtx proteins showed a high level of activity against susceptible C. quinquefasciatus mosquitoes, with 50% lethal concentrations (LC(50)) of Mtx-1 and Mtx-2 of 0.246 and 4.13 microg/ml, respectively. The LC(50)s were 0.406 to 0.430 microg/ml when Mtx-1 or Mtx-2 was mixed with B. sphaericus, and synergy improved activity and reduced resistance levels. When the proteins were combined with a recombinant Bacillus thuringiensis strain that produces Cry11Aa, the mixtures were highly active against Cry11A-resistant larvae and resistance was also reduced. The mixture of two Mtx toxins and B. sphaericus was 10 times more active against susceptible mosquitoes than B. sphaericus alone, demonstrating the influence of relatively low concentrations of these toxins. These results show that, similar to Cyt toxins from B. thuringiensis subsp. israelensis, Mtx toxins can increase the toxicity of other mosquitocidal proteins and may be useful for both increasing the activity of commercial bacterial larvicides and managing potential resistance to these substances among mosquito populations.
蚊虫抗药性分子机制研究进展%Progress in molecular mechanisms of mosquito resistance to insecticides
Institute of Scientific and Technical Information of China (English)
史琦琪; 程鹏; 公茂庆
蚊虫抗药性机制的研究对抗药性监测、治理及新的卫生杀虫剂研制具有重要意义。现已对与蚊虫杀虫剂抗性的相关行为、生理代谢活动及作用靶标等进行了全面研究。目前证实蚊虫抗药性与行为、生理功能改变、解毒功能增强和靶标不敏感性等有关。近年来,随着分子生物学、基因组学以及遗传学的发展,蚊虫抗药性的分子机制有了新的研究进展,已发现并克隆了一些靶标基因,与抗药性相关的基因突变也得到普遍验证。该文综述了蚊虫的抗药性机制在分子生物学水平的研究进展,重点阐述了与蚊虫抗药性相关基因的扩增、表达及基因结构的改变等。%Studies on the mechanisms of insecticide resistance is very important to develop effective strategies for monitoring and managing insecticide resistance as well as new pesticide research. In the past several decades, a great deal of studies on insecticide resistance mechanisms, such as behavior, physiological function, metabolic action and target⁃site have been reported. It has been proven correct that mechanisms of insecticide resistance were confirmed by changed behavior, modified physiological function, enhanced detoxification and target⁃site insensitivity. Recently, with the development of the molecular biology, insect genomes and genetics, the molecular mechanism of insect resistance has been elucidated to much greater details. Some target genes have been identified and cloned in many mosquitoes. Some insecticide resistance related mutations have been screened out in some mosquitoes. This paper reviewed the progress in molecular mechanisms of mosquito resistance to insecticides. The alterations in genes related to insecticide resistance including amplification, over⁃expression and structure change were introduced in details.
Assay of Acetylcholinesterase Activity and Electrochemical Determination of Fenthion in Oil-in-water Emulsion
Institute of Scientific and Technical Information of China (English)
Sun Kai; He JingJing; Miao YuQing
@@ Organophosphates (OPs) have been widely used as pesticides,insecticides or even chemical warfare agents.Acetylcholinesterase (ACHE) inhibition has been employed to develop verious assay methods for detection of pesticides with the advantages of low cost,simple procedure and quick assay time.The study of acetylcholinesterase (ACHE) activity and OPs inhibition in the solution containing organic solvent is extremely important owing to poor solubility of Ops in water and a higher solubility in organic solvents.
Multiple insecticide resistance/susceptibility status of Culex quinquefasciatus, principal vector of bancroftian filariasis from filaria endemic areas of northern India
Institute of Scientific and Technical Information of China (English)
Kaushal Kumar; Abhay K Sharma; Sarita Kumar; Sunita Patel; Manas Sarkar; Chauhan LS
Objective:To understand the insecticide resistance status of Culex quinquefasciatus Say (Diptera:Culicidae) (Cx. Quinquefasciatus) to deltamethrin, cyfluthrin, permethrin, lambdacyhalothrin, DDT and malathion in filarial endemic areas of Uttar Pradesh, India. Methods:Insecticide susceptibility assays were performed on wild-caught adult female Cx. quinquefasciatus mosquitoes to deltamethrin (0.05%), cyfluthrin (0.15%), permethrin (0.75%), lambdacyhalothrin (0.05%), malathion (5.0%) and DDT (4.0%), the discriminating doses recommended by the World Health Organisation (WHO). Results: The data showed that Cx. quinquefasciatus is highly resistant to DDT and malathion;the mortality was 28.33%and 27.5%, respectively and incipient resistance to synthetic pyrethroids (deltamethrin, cyfluthrin, permethrin, and lambdacyhalothrin), where mortality ranged from 95.83%in permethrin to 98.33%in cyfluthrin and lambdacyhalothrin. Knockdown times (KDT50) in response to synthetic pyrethroids varied significantly between different insecticides (P<0.01) from 31.480 min for permethrin to 21.650 for cyfluthrin. Conclusions:The results presents here provide the status report of the insecticide resistance/susceptibility of Cx. quinquefasciatus in major filaria endemic areas of northern India.
Role of a gamma-aminobutryic acid (GABA) receptor mutation in the evolution and spread of Diabrotica virgifera virgifera resistance to cyclodiene insecticides
An alanine to serine amino acid substitution within the Rdl subunit of the gamma-aminobutyric acid (GABA) receptor confers resistance to cyclodiene insecticides in many species. The corn rootworm, Diabrotica virgifera virgifera, is a damaging pest of cultivated corn that was partially controlled by ...
The draft genome of whitefly Bemisia tabaci MEAM1, a global crop pest, provides novel insights into virus transmission, host adaptation, and insecticide resistance
Whiteflies are among the most important agricultural pests. They have a broad range of host plants and exceptional ability to transmit a large number of plant viruses, and can rapidly evolve insecticide resistance. Here we present a high-quality draft genome of the whitefly, Bemisia tabaci. Comparat...
Effect of transmission reduction by insecticide-treated bednets (ITNs on antimalarial drug resistance in western Kenya.
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Monica Shah
Full Text Available Despite the clear public health benefit of insecticide-treated bednets (ITNs, the impact of malaria transmission-reduction by vector control on the spread of drug resistance is not well understood. In the present study, the effect of sustained transmission reduction by ITNs on the prevalence of Plasmodium falciparum gene mutations associated with resistance to the antimalarial drugs sulfadoxine-pyrimethamine (SP and chloroquine (CQ in children under the age of five years was investigated during an ITN trial in Asembo area, western Kenya. During the ITN trial, the national first line antimalarial treatment changed from CQ to SP. Smear-positive samples collected from cross sectional surveys prior to ITN introduction (baseline, n = 250 and five years post-ITN intervention (year 5 survey, n = 242 were genotyped for single nucleotide polymorphisms (SNPs at dhfr-51, 59, 108, 164 and dhps-437, 540 (SP resistance, and pfcrt-76 and pfmdr1-86 (CQ resistance. The association between the drug resistance mutations and epidemiological variables was evaluated. There were significant increases in the prevalence of SP dhps mutations and the dhfr/dhps quintuple mutant, and a significant reduction in the proportion of mixed infections detected at dhfr-51, 59 and dhps-437, 540 SNPs from baseline to the year 5 survey. There was no change in the high prevalence of pfcrt-76 and pfmdr1-86 mutations. Multivariable regression analysis further showed that current antifolate use and year of survey were significantly associated with more SP drug resistance mutations. These results suggest that increased antifolate drug use due to drug policy change likely led to the high prevalence of SP mutations 5 years post-ITN intervention and reduced transmission had no apparent effect on the existing high prevalence of CQ mutations. There is no evidence from the current study that sustained transmission reduction by ITNs reduces the prevalence of genes associated with malaria
Turning cigarette butt waste into an alternative control tool against an insecticide-resistant mosquito vector.
Dieng, Hamady; Rajasaygar, Sudha; Ahmad, Abu Hassan; Ahmad, Hamdan; Rawi, Che Salmah Md; Zuharah, Wan Fatma; Satho, Tomomitsu; Miake, Fumio; Fukumitsu, Yuki; Saad, Ahmad Ramli; Ghani, Idris Abd; Vargas, Ronald Enrique Morales; Majid, Abdul Hafiz Ab; Abubakar, Sazaly
Annually, 4.5 trillion cigarette butts (CBs) are flicked into our environment. Evidence exists that CB waste is deadly to aquatic life, but their lethality to the aquatic life of the main dengue vector is unknown. CBs are full of toxicants that occur naturally, during planting and manufacturing, which may act as larvicidal agents. We assessed Aedes aegypti vulnerability to Marlboro butts during its development. Overall, CBs showed insecticidal activities against larvae. At early phases of development, mortality rates were much higher in two CBs solution (2CBSol) and 3CBSol microcosms (MICRs). Larval survival gradually decreased with development in 1CBSol-MICRs. However, in great presence of CBs, mortality was high even for the late developmental stages. These results suggest that A. aegypti larvae are vulnerable to CB presence in their habitats, but this effect was seen most during the early developmental phases and in the presence of increased amounts of cigarette remnants. CB filters are being used as raw material in many sectors, i.e., brick, art, fashion, plastic industries, as a practical solution to the pollution problem, the observed butt waste toxicity to mosquito larvae open new avenues for the identification of novel insecticide products.
Bioefficacy of long-lasting insecticidal nets against pyrethroid-resistant populations of Anopheles gambiae s.s. from different malaria transmission zones in Uganda
Okia, Michael; Ndyomugyenyi, Richard; Kirunda, James; Byaruhanga, Anatol; Adibaku, Seraphine; Lwamafa, Denis K; Kironde, Fred
Background There are major concerns over sustaining the efficacy of current malaria vector control interventions given the rapid spread of resistance, particularly to pyrethroids. This study assessed the bioefficacy of five WHO-recommended long-lasting insecticidal nets (LLINs) against pyrethroid-resistant Anopheles gambiae field populations from Uganda. Methods Adult An. gambiae from Lira, Tororo, Wakiso and Kanungu districts were exposed to permethrin (0.75%) or deltamethrin (0.05%) in stan...
Evidence of multiple/cross resistance to Bt and organophosphate insecticides in Puerto Rico population of the fall armyworm, Spodoptera frugiperda.
Zhu, Yu Cheng; Blanco, Carlos A; Portilla, Maribel; Adamczyk, John; Luttrell, Randall; Huang, Fangneng
Fall armyworm (FAW) is a damaging pest of many economic crops. Long-term use of chemical control prompted resistance development to many insecticide classes. Many populations were found to be significantly less susceptible to major Bt toxins expressed in transgenic crops. In this study, a FAW strain collected from Puerto Rico (PR) with 7717-fold Cry1F-resistance was examined to determine if it had also developed multiple/cross resistance to non-Bt insecticides. Dose response assays showed that the PR strain developed 19-fold resistance to acephate. Besides having a slightly smaller larval body weight and length, PR also evolved a deep (2.8%) molecular divergence in mitochondrial oxidase subunit II. Further examination of enzyme activities in the midgut of PR larvae exhibited substantial decreases of alkaline phosphatase (ALP), aminopeptidase (APN), 1-NA- and 2-NA-specific esterase, trypsin, and chymotrypsin activities, and significant increases of PNPA-specific esterase and glutathione S-transferase (GST) activities. When enzyme preparations from the whole larval body were examined, all three esterase, GST, trypsin, and chymotrypsin activities were significantly elevated in the PR strain, while ALP and APN activities were not significantly different from those of susceptible strain. Data indicated that multiple/cross resistances may have developed in the PR strain to both Bt toxins and conventional insecticides. Consistently reduced ALP provided evidence to support an ALP-mediated Bt resistance mechanism. Esterases and GSTs may be associated with acephate resistance through elevated metabolic detoxification. Further studies are needed to clarify whether and how esterases, GSTs, and other enzymes (such as P450s) are involved in cross resistance development to Bt and other insecticide classes.
The knockdown resistance mutation and knockdown time in Anopheles gambiae collected from Mali evaluated through a bottle bioassay and a novel insecticide-treated net bioassay.
Fryxell, Rebecca T Trout; Seifert, Stephanie N; Lee, Yoosook; Sacko, Adama; Lanzaro, Gregory; Cornel, Anthony
Successful malaria management in Mali includes the use of pyrethroids and insecticide-treated nets (ITNs) for mosquito control; however, management is threatened by the spread of insecticide resistance detected via the knockdown resistance (kdr) allele. In a preliminary study, we compared the knockdown times of Anopheles gambiae from Mali using a novel ITN bioassay and the World Health Organization (WHO) bottle bioassay. Additionally, the frequency and relationship between kdr genotypes, molecular forms, and pyrethroid resistance were analyzed. The S molecular form was predominant and accounted for 76% of the assayed population. Both kdr resistant alleles, West Africa resistant (kdr-w) and East Africa resistant (kdr-e), were observed. There was no significant difference in knockdown time based on kdr genotype or molecular form of individual mosquitoes, but mosquitoes in the ITN bioassay homozygous for the kdr-w allele were knocked down significantly faster than those in the WHO bottle bioassay. The ITN bioassay provides an additional indicator of insecticide efficacy because ITNs, frequently used within homes, are the most common form of vector control and malaria prevention, and the ITN bioassays can evaluate seasonal field effects.
Insecticidal resistance of Musca domestica in urban areas of Liaoning%辽宁省4市城区家蝇抗药性调查
Institute of Scientific and Technical Information of China (English)
李志; 白玉银; 李鑫; 邢丽; 贾吉中; 王陆玲; 刘晓鹏; 王忠利
目的 了解辽宁省不同市区家蝇抗药性状况,为科学地使用杀虫剂提供依据.方法 采用点滴法.用微量点滴器,将丙酮配制的试验药剂,点滴于家蝇中胸背板进行测试.结果 辽宁省抚顺、本溪、辽阳、鞍山市的家蝇对4种常用杀虫剂均产生了不同程度的抗药性,以溴氰菊酯的抗性最为突出,4市家蝇对该杀虫剂的平均抗性系数为61.60倍,对残杀威的抗药性次之,平均抗性系数为22.65倍,对高效氯氰菊酯和敌敌畏的平均抗性系数分别为8.71和4.72倍.结论 应采取科学的方法使用杀虫剂,有效控制家蝇的抗药性增长.%Objective To determine the insecticidal resistance of Musca domestica in urban areas of Liaoning in order to provide the basis for scientific administration of insecticides in fly control.Methods Topical application of insecticides solved in acetone was made to the mesonotum of M.domestica.Results Different degrees of resistance of M.domestica to four commonly used insecticides were observed in Fushun, Benxi, Liaoyang, Anshan city of Liaoning.The resistance to deltamethrin was the highest, with the average resistance coefficient of 61.60, followed by the resistance to propoxur with an average resistance coefficient of 22.65.The average resistance coefficients to alpha-cypermethrin and dichlorvos were 8.71 and 4.72, respectively.Conclusion Insecticides should be applied scientifically to effectively curb the increase in insecticidal resistance ofM.domestica.
Proteases as Insecticidal Agents
Robert L. Harrison; Bonning, Bryony C.
Proteases from a variety of sources (viruses, bacteria, fungi, plants, and insects) have toxicity towards insects. Some of these insecticidal proteases evolved as venom components, herbivore resistance factors, or microbial pathogenicity factors, while other proteases play roles in insect development or digestion, but exert an insecticidal effect when over-expressed from genetically engineered plants or microbial pathogens. Many of these proteases are cysteine proteases, although insect-toxic...
Analysis of insecticide resistance-related genes of the Carmine spider mite Tetranychus cinnabarinus based on a de novo assembled transcriptome.
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Zhifeng Xu
Full Text Available The carmine spider mite (CSM, Tetranychus cinnabarinus, is an important pest mite in agriculture, because it can develop insecticide resistance easily. To gain valuable gene information and molecular basis for the future insecticide resistance study of CSM, the first transcriptome analysis of CSM was conducted. A total of 45,016 contigs and 25,519 unigenes were generated from the de novo transcriptome assembly, and 15,167 unigenes were annotated via BLAST querying against current databases, including nr, SwissProt, the Clusters of Orthologous Groups (COGs, Kyoto Encyclopedia of Genes and Genomes (KEGG and Gene Ontology (GO. Aligning the transcript to Tetranychus urticae genome, the 19255 (75.45% of the transcripts had significant (e-value <10-5 matches to T. urticae DNA genome, 19111 sequences matched to T. urticae proteome with an average protein length coverage of 42.55%. Core Eukaryotic Genes Mapping Approach (CEGMA analysis identified 435 core eukaryotic genes (CEGs in the CSM dataset corresponding to 95% coverage. Ten gene categories that relate to insecticide resistance in arthropod were generated from CSM transcriptome, including 53 P450-, 22 GSTs-, 23 CarEs-, 1 AChE-, 7 GluCls-, 9 nAChRs-, 8 GABA receptor-, 1 sodium channel-, 6 ATPase- and 12 Cyt b genes. We developed significant molecular resources for T. cinnabarinus putatively involved in insecticide resistance. The transcriptome assembly analysis will significantly facilitate our study on the mechanism of adapting environmental stress (including insecticide in CSM at the molecular level, and will be very important for developing new control strategies against this pest mite.
Transcriptome Analysis of an Insecticide Resistant Housefly Strain: Insights about SNPs and Regulatory Elements in Cytochrome P450 Genes.
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Khalid Mahmood
Full Text Available Insecticide resistance in the housefly, Musca domestica, has been investigated for more than 60 years. It will enter a new era after the recent publication of the housefly genome and the development of multiple next generation sequencing technologies. The genetic background of the xenobiotic response can now be investigated in greater detail. Here, we investigate the 454-pyrosequencing transcriptome of the spinosad-resistant 791spin strain in relation to the housefly genome with focus on P450 genes.The de novo assembly of clean reads gave 35,834 contigs consisting of 21,780 sequences of the spinosad resistant strain. The 3,648 sequences were annotated with an enzyme code EC number and were mapped to 124 KEGG pathways with metabolic processes as most highly represented pathway. One hundred and twenty contigs were annotated as P450s covering 44 different P450 genes of housefly. Eight differentially expressed P450s genes were identified and investigated for SNPs, CpG islands and common regulatory motifs in promoter and coding regions. Functional annotation clustering of metabolic related genes and motif analysis of P450s revealed their association with epigenetic, transcription and gene expression related functions. The sequence variation analysis resulted in 12 SNPs and eight of them found in cyp6d1. There is variation in location, size and frequency of CpG islands and specific motifs were also identified in these P450s. Moreover, identified motifs were associated to GO terms and transcription factors using bioinformatic tools.Transcriptome data of a spinosad resistant strain provide together with genome data fundamental support for future research to understand evolution of resistance in houseflies. Here, we report for the first time the SNPs, CpG islands and common regulatory motifs in differentially expressed P450s. Taken together our findings will serve as a stepping stone to advance understanding of the mechanism and role of P450s in
Partial purification and characterization of {alpha}-amylases from one insecticide-resistant population of Sitophilus zeamais
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Lopes, K.V.; Oliveira, M.G.A.; Paixao, G.P.; Visotto, L.E. [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Bioquimica e Biologia Molecular; Veloso, R.V.S.; Marinho, J.S.; Guedes, R.N.C. [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Biologia Animal; Oliveira, J.A. [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Quimica
Full text: {alpha}-Amylases (EC 18.104.22.168) constitute a family of endo-amylases that catalyze the hydrolysis of a-D- (1,4)-glucan linkages in st ach components and various other related carbohydrates. They play a central role in carbohydrate metabolism of animals, plants and microorganisms. Many insects, especially those that feed on grain products during larval and/or adult life, depend on their amylases for survival. This is particularly true for the Sitophilus zeamais Motschulsky, a cosmopolitan pest of stored products. It is mainly controlled by insecticides. Amylases from adults of S.zeamais insecticide-resistant were purified by using a sequential procedure of glycogen-complex precipitation and ion exchange chromatography. Specific activity increased from 58,0454 AU/dL/mg protein in the crude homogenate to 2558,8720 AU/dL/mg protein in the final purified sample. Amylase unit (AU/dL) refers to the amount of amylase that hydrolysis 10 mg starch in 30 min at 37 deg C. The purified amylase ran as a single protein band on SDS-PAGE. From a plot of log molecular weight against relative mobility in 10% acrylamide gel, molecular weight was estimated to be 56 kDa. The enzyme had a K{sub m} of 0,2243 g/L for soluble starch and was most active at ph 5,0. The temperature of major activity was 40 deg C. The activity of enzyme was unaffected by presence or absence of Cl{sup -} and Ca{sup 2+}.
RNA interference of NADPH-cytochrome P450 reductase results in reduced insecticide resistance in the bed bug, Cimex lectularius.
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Fang Zhu
Full Text Available BACKGROUND: NADPH-cytochrome P450 reductase (CPR plays a central role in cytochrome P450 action. The genes coding for P450s are not yet fully identified in the bed bug, Cimex lectularius. Hence, we decided to clone cDNA and knockdown the expression of the gene coding for CPR which is suggested to be required for the function of all P450s to determine whether or not P450s are involved in resistance of bed bugs to insecticides. METHODOLOGY/PRINCIPAL FINDINGS: The full length Cimex lectularius CPR (ClCPR cDNA was isolated from a deltamethrin resistant bed bug population (CIN-1 using a combined PCR strategy. Bioinformatics and in silico modeling were employed to identify three conserved binding domains (FMN, FAD, NADP, a FAD binding motif, and the catalytic residues. The critical amino acids involved in FMN, FAD, NADP binding and their putative functions were also analyzed. No signal peptide but a membrane anchor domain with 21 amino acids which facilitates the localization of ClCPR on the endoplasmic reticulum was identified in ClCPR protein. Phylogenetic analysis showed that ClCPR is closer to the CPR from the body louse, Pediculus humanus corporis than to the CPRs from the other insect species studied. The ClCPR gene was ubiquitously expressed in all tissues tested but showed an increase in expression as immature stages develop into adults. We exploited the traumatic insemination mechanism of bed bugs to inject dsRNA and successfully knockdown the expression of the gene coding for ClCPR. Suppression of the ClCPR expression increased susceptibility to deltamethrin in resistant populations but not in the susceptible population of bed bugs. CONCLUSIONS/SIGNIFICANCE: These data suggest that P450-mediated metabolic detoxification may serve as one of the resistance mechanisms in bed bugs.
Variations in susceptibility to common insecticides and resistance mechanisms among morphologically identified sibling species of the malaria vector Anopheles subpictus in Sri Lanka
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Surendran Sinnathamby N
Full Text Available Abstract Background Anopheles subpictus s.l., an important malaria vector in Sri Lanka, is a complex of four morphologically identified sibling species A-D. Species A-D reportedly differ in bio-ecological traits that are important for vector control. We investigated possible variations that had not been reported previously, in the susceptibility to common insecticides and resistance mechanisms among the An. subpictus sibling species. Methods Adult An. subpictus were collected from localities in four administrative districts in the dry zone of Sri Lanka. Single female isoprogeny lines were established and sibling species status determined according to reported egg morphology. World Health Organization's standard protocols were used for insecticide bioassays and biochemical assays to determine insecticide susceptibility and resistance mechanisms. Susceptibility of mosquitoes was tested against DDT (5%, malathion (4%, deltamethrin (0.05% and λ-cyhalothrin (0.05%. Biochemical basis for resistance was determined through assaying for esterase, glutathione-S-transferase and monooxygenase activities and the insensitivity of acetycholinesterase (AChE to propoxur inhibition. Results All sibling species were highly resistant to DDT. However there were significant differences among the sibling species in their susceptibility to the other tested insecticides. Few species A could be collected for testing, and where testing was possible, species A tended to behave more similarly to species C and D than to B. Species B was more susceptible to all the tested insecticides than the other sibling species. This difference may be attributed to the predominance of species B in coastal areas where selection pressure due to indoor residual spraying of insecticides (IRS was lower. However there were significant differences between the more inland species C and D mainly towards pyrethroids. Higher GST activities in species C and D might have contributed to their greater
Tolerance to the carbamate insecticide propoxur.
Costa, L G; Hand, H; Schwab, B W; Murphy, S D
Male mice were given the carbamate insecticide propoxur (2-isopropoxy phenyl methylcarbamate; Baygon) in the drinking water at weekly increasing concentrations (from 50 to 2000 ppm), for a period of 6 weeks. At the end of the treatment the LD50 for propoxur was significantly higher in the treated animals as compared with controls. Propoxur-treated animals were also resistant to the hypothermic effect of an acute administration of the same compound. Groups of mice were challenged with the cholinergic agonist carbachol at intervals during the drinking water dosing and at its end. No differences in sensitivity to carbachol acute toxicity were found between control and treated animals. Propoxur-tolerant animals were also not resistant to the hypothermic effect of oxotremorine, another cholinergic agonist. [3H]Quinuclidinyl benzilate ([3H]QNB) binding (a measure of muscarinic receptor density and affinity) in forebrain, hindbrain and ileum never differed in control and treated mice. The possibility that repeated administrations of propoxur induced increased metabolic inactivation was tested by measuring hexobarbital sleeping time and carboxylesterase activity in treated and control mice. No changes in tissue carboxylesterase activities occurred but hexobarbital sleeping time was significantly reduced in propoxur treated animals suggesting an induction of hepatic microsomal enzymes. These results suggest that tolerance to propoxur is not mediated by a decrease of cholinergic receptors, as reported for other acetylcholinesterase inhibitors, but possibly by an enhancement of its metabolism.
Candidate genes revealed by a genome scan for mosquito resistance to a bacterial insecticide: sequence and gene expression variations
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David Jean-Philippe
Full Text Available Abstract Background Genome scans are becoming an increasingly popular approach to study the genetic basis of adaptation and speciation, but on their own, they are often helpless at identifying the specific gene(s or mutation(s targeted by selection. This shortcoming is hopefully bound to disappear in the near future, thanks to the wealth of new genomic resources that are currently being developed for many species. In this article, we provide a foretaste of this exciting new era by conducting a genome scan in the mosquito Aedes aegypti with the aim to look for candidate genes involved in resistance to Bacillus thuringiensis subsp. israelensis (Bti insecticidal toxins. Results The genome of a Bti-resistant and a Bti-susceptible strains was surveyed using about 500 MITE-based molecular markers, and the loci showing the highest inter-strain genetic differentiation were sequenced and mapped on the Aedes aegypti genome sequence. Several good candidate genes for Bti-resistance were identified in the vicinity of these highly differentiated markers. Two of them, coding for a cadherin and a leucine aminopeptidase, were further examined at the sequence and gene expression levels. In the resistant strain, the cadherin gene displayed patterns of nucleotide polymorphisms consistent with the action of positive selection (e.g. an excess of high compared to intermediate frequency mutations, as well as a significant under-expression compared to the susceptible strain. Conclusion Both sequence and gene expression analyses agree to suggest a role for positive selection in the evolution of this cadherin gene in the resistant strain. However, it is unlikely that resistance to Bti is conferred by this gene alone, and further investigation will be needed to characterize other genes significantly associated with Bti resistance in Ae. aegypti. Beyond these results, this article illustrates how genome scans can build on the body of new genomic information (here, full
Research Progress on Insecticide Resistance and Mechanism in Diamondback Moth%小菜蛾抗药性及抗性机制研究进展
Institute of Scientific and Technical Information of China (English)
侯艳红; 姬琨
小菜蛾抗药性发生严重,目前已经对多类杀虫剂产生了抗药性,该文主要对小菜蛾抗药性发生现状、抗性机制、杀虫剂之间的交互抗性等方面的研究进展进行了讨论。%The diamondback moth, Plutella xylostella Linnaeus became resistant seriously to many insecticides. The pesticides resistance,mechanism and cross-resistance were systematiclly discussed in this paper.
Pinpointing P450s Associated with Pyrethroid Metabolism in the Dengue Vector, Aedes aegypti: Developing New Tools to Combat Insecticide Resistance
BACKGROUND: Pyrethroids are increasingly used to block the transmission of diseases spread by Aedes aegypti such as dengue and yellow fever. However, insecticide resistance poses a serious threat, thus there is an urgent need to identify the genes and proteins associated with pyrethroid resistance in order to produce effective counter measures. In Ae. aegypti, overexpression of P450s such as the CYP9J32 gene have been linked with pyrethroid resistance. Our aim was to confirm the role of CYP9J...
The emergence of insecticide resistance in central Mozambique and potential threat to the successful indoor residual spraying malaria control programme
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Wilding Craig S
Full Text Available Abstract Background Malaria vector control by indoor residual spraying was reinitiated in 2006 with DDT in Zambézia province, Mozambique. In 2007, these efforts were strengthened by the President's Malaria Initiative. This manuscript reports on the monitoring and evaluation of this programme as carried out by the Malaria Decision Support Project. Methods Mosquitoes were captured daily through a series of 114 window exit traps located at 19 sentinel sites, identified to species and analysed for sporozoites. Anopheles mosquitoes were collected resting indoors and tested for insecticide resistance following the standard WHO protocol. Annual cross sectional household parasite surveys were carried out to monitor the impact of the control programme on prevalence of Plasmodium falciparum in children aged 1 to 15 years. Results A total of 3,769 and 2,853 Anopheles gambiae s.l. and Anopheles funestus, respectively, were captured from window exit traps throughout the period. In 2010 resistance to the pyrethroids lambda-cyhalothrin and permethrin and the carbamate, bendiocarb was detected in An. funestus. In 2006, the sporozoite rate in An. gambiae s.s. was 4% and this reduced to 1% over 4 rounds of spraying. The sporozoite rate for An. funestus was also reduced from 2% to 0 by 2008. Of the 437 Anopheles arabiensis identified, none were infectious. Overall prevalence of P. falciparum in the sentinel sites fell from 60% to 32% between October 2006 and October 2008. Conclusion Both An. gambiae s.s. and An. funestus were controlled effectively with the DDT-based IRS programme in Zambézia, reducing disease transmission and burden. However, the discovery of pyrethroid resistance in the province and Mozambique's policy change away from DDT to pyrethroids for IRS threatens the gains made here.
Insecticide resistance in Anopheles gambiae: data from the first year of a multi-country study highlight the extent of the problem
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Sagnon N'Falé
Full Text Available Abstract Background Insecticide resistance in malaria vectors is a growing concern in many countries which requires immediate attention because of the limited chemical arsenal available for vector control. The current extent and distribution of this resistance in many parts of the continent is unknown and yet such information is essential for the planning of effective malaria control interventions. Methods In 2008, a network was established, with financial support from WHO/TDR, to investigate the extent of insecticide resistance in malaria vectors in five African countries. Here, the results of bioassays on Anopheles gambiae sensu lato from two rounds of monitoring from 12 sentinel sites in three of the partner countries are reported. Results Resistance is very heterogeneous even over relatively small distances. Furthermore, in some sites, large differences in mortality rates were observed during the course of the malaria transmission season. Using WHO diagnostic doses, all populations from Burkina Faso and Chad and two of the four populations from Sudan were classified as resistant to permethrin and/or deltamethrin. Very high frequencies of DDT resistance were found in urban areas in Burkina Faso and Sudan and in a cotton-growing district in Chad. In areas where both An. gambiae s.s. and Anopheles arabiensis were present, resistance was found in both species, although generally at a higher frequency in An gambiae s.s. Anopheles gambiae s.l. remains largely susceptible to the organophosphate fenitrothion and the carbamate bendiocarb in the majority of the sentinel sites with the exception of two sites in Burkina Faso. In the cotton-growing region of Soumousso in Burkina Faso, the vector population is resistant to all four classes of insecticide available for malaria control. Conclusions Possible factors influencing the frequency of resistant individuals observed in the sentinel sites are discussed. The results of this study highlight the
Novel Detection of Insecticide Resistance Related P450 Genes and Transcriptome Analysis of the Hemimetabolous Pest Erthesina fullo (Thunberg) (Hemiptera: Heteroptera).
Liu, Yang; Wu, Haoyang; Xie, Qiang; Bu, Wenjun
Erthesina fullo (Thunberg, 1783) is an economically important heteropteran species in China. Since only three nucleotide sequences of this species (COI, 16S rRNA, and 18S rRNA) appear in the GenBank database so far, no analysis of the molecular mechanisms underlying E. fullo's resistance to insecticide and environmental stress has been accomplished. We reported a de novo assembled and annotated transcriptome for adult E. fullo using the Illumina sequence system. A total of 53,359,458 clean reads of 4.8 billion nucleotides (nt) were assembled into 27,488 unigenes with an average length of 750 bp, of which 17,743 (64.55%) were annotated. In the present study, we identified 88 putative cytochrome P450 sequences and analyzed the evolution of cytochrome P450 superfamilies, genes of the CYP3 clan related to metabolizing xenobiotics and plant natural compounds, in E. fullo, increasing the candidate genes for the molecular mechanisms of insecticide resistance in P450. The sequenced transcriptome greatly expands the available genomic information and could allow a better understanding of the mechanisms of insecticide resistance at the systems biology level.
Breeding and Identification of Insect-Resistant Rice by Transferring Two Insecticidal Genes, sbk and sck
Institute of Scientific and Technical Information of China (English)
ZHANG Qi-jun; LI Cong; LIU Shao-kui; LAI Dong; QI Qing-ming; LU Chuan-gen
The plasmid of pCDMARUBA-Hyg,which contained two insect-resistance genes,sbk (modified from Cry1A(c)) and sck (modified from CpTI),was transformed into an Agrobacterium EHA105 for infection of the calli of a super japonica rice Nanjing 45.Primarily,using polymerase chain reaction (PCR) detection with the primers of sbk and sck genes,42 positive transgenic plants that were marker-free and contained the two target genes were selected from 97 regenerated plants.Results of southern-blotting indicated that 23,11,5,2 and 1 plants had one,two,three,four and five copies of the transformed genes,respectively.Analysis of reverse transcription PCR (RT-PCR) and Bt gene testing paper showed that 28 T3 generation plants derived from four transgenic plants having a single copy were insect-resistant.Feeding experiment with rice stem borer revealed that the insect resistance was greatly increased with the larva mortality ranging from 94% to 100%.In addition,among the transgenic plants,three T3 transgenic plants possessed some desirable characteristics for breeding and production,such as plant height,seed-setting rate,1000-grain weight and larva mortality.The mechanism of insect resistance of Bt gene and its application in rice transgenic research were also briefly discussed.
Optimization of conditions for assaying activity of acetylcholinesterase in Bombus hypocrita(Hymenoptera: Apidae)and its sensitivity to six common insecticides%小峰熊蜂头部乙酰胆碱酯酶测定条件的优化及其对六种常用杀虫剂的敏感性
Institute of Scientific and Technical Information of China (English)
廖秀丽; 罗术东; 伍翔; 吴杰
小峰熊蜂Bombus hypocrita是我国优势熊蜂种群之一,因其易于饲养、群势较强且授粉性能优良而成为我国设施农业常用优良授粉蜂种,但常受到以乙酰胆碱酯酶(AChE)为靶标酶的有机磷和氨基甲酸酯类杀虫剂的危害.为合理规避这两类杀虫剂对熊蜂的危害,同时也为完善熊蜂授粉配套技术和保护野生熊蜂资源提供理论基础,本研究利用正交试验对小峰熊蜂头部乙酰胆碱酯酶活性的测定条件进行了优化,并明确了 6种常用有机磷和氨基甲酸酯类杀虫剂对乙酰胆碱酯酶活性的影响.结果表明:各测定因素对小峰熊蜂乙酰胆碱酯酶活性测定影响的大小顺序依次为:酶浓度>pH>温度>底物浓度>反应时间;小峰熊蜂头部乙酰胆碱酯酶活性的最适反应条件为:酶浓度0.25 g蛋白质/L,底物浓度0.8 mmol/L,pH值7.5,温度40℃,反应时间5 min.毒死蜱、三唑磷、丙溴磷、异丙威、仲丁威和残杀威6种杀虫剂对小峰熊蜂头部乙酰胆碱酯酶离体抑制作用均呈现明显的剂量-效应关系,其抑制中浓度IC50分别为0.39,1.79,0.42,0.04,0.43和0.63 mmol/L.这6种杀虫剂对小峰熊蜂AChE抑制作用的强弱依次为:异丙威>毒死蜱>三唑磷>仲丁威>残杀威>丙溴磷,即小峰熊蜂对异丙威最敏感,而对丙溴磷的敏感性最弱.%Bombus hypocrita ( Hymenoptera: Apidae) is one of the dominant bumblebees in China, and is widely used as one of the most crucial pollinators in greenhouse due to easy mass-rearing, strong population and effective pollinating performance. However, it is often threatened by organophosphate and carbamate insecticides which are widely used in China, as these insecticides can inhibit the acetylcholinesterase ( AChE) activity in insects. In order to avoid harm to bumblebees by these insecticides and improve the pollination technology and conservation of bumblebees, we optimized the reaction conditions to assay
Surveillance, insecticide resistance and control of an invasive Aedes aegypti (Diptera: Culicidae population in California [version 3; referees: 2 approved
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Anthony J. Cornel
Full Text Available The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B, when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV trials using a new formulation of deltamethrin (DeltaGard® demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath after a single truck mounted aerial ULV application in residential areas.
Point mutations associated with insecticide resistance in the Drosophila cytochrome P450 Cyp6a2 enable DDT metabolism.
Amichot, Marcel; Tarès, Sophie; Brun-Barale, Alexandra; Arthaud, Laury; Bride, Jean-Marc; Bergé, Jean-Baptiste
Three point mutations R335S, L336V and V476L, distinguish the sequence of a cytochrome P450 CYP6A2 variant assumed to be responsible for 1,1,1-trichloro-2,2-bis-(4'-chlorophenyl)ethane (DDT) resistance in the RDDT(R) strain of Drosophila melanogaster. To determine the impact of each mutation on the function of CYP6A2, the wild-type enzyme (CYP6A2wt) of Cyp6a2 was expressed in Escherichia coli as well as three variants carrying a single mutation, the double mutant CYP6A2vSV and the triple mutant CYP6A2vSVL. All CYP6A2 variants were less stable than the CYP6A2wt protein. Two activities enhanced in the RDDT(R) strain were measured with all recombinant proteins, namely testosterone hydroxylation and DDT metabolism. Testosterone was hydroxylated at the 2beta position with little quantitative variation among the variants. In contrast, metabolism of DDT was strongly affected by the mutations. The CYP6A2vSVL enzyme had an enhanced metabolism of DDT, producing dicofol, dichlorodiphenyldichloroethane and dichlorodiphenyl acetic acid. The apparent affinity of the enzymes CYP6A2wt and CYP6A2vSVL for DDT and testosterone was not significantly different as revealed by the type I difference spectra. Sequence alignments with CYP102A1 provided clues to the positions of the amino acids mutated in CYP6A2. These mutations were found spatially clustered in the vicinity of the distal end of helix I relative to the substrate recognition valley. Thus this area, including helix J, is important for the structure and activity of CYP6A2. Furthermore, we show here that point mutations in a cytochrome P450 can have a prominent role in insecticide resistance.
Surveillance, insecticide resistance and control of an invasive Aedes aegypti (Diptera: Culicidae population in California [version 2; referees: 2 approved
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Anthony J. Cornel
Full Text Available The invasion and subsequent establishment in California of Aedes aegypti in 2013 has created new challenges for local mosquito abatement and vector control districts. Studies were undertaken to identify effective and economical strategies to monitor the abundance and spread of this mosquito species as well as for its control. Overall, BG Sentinel (BGS traps were found to be the most sensitive trap type to measure abundance and spread into new locations. Autocidal-Gravid-Ovitraps (AGO-B, when placed at a site for a week, performed equally to BGS in detecting the presence of female Ae. aegypti. Considering operational cost and our findings, we recommend use of BGS traps for surveillance in response to service requests especially in locations outside the known infestation area. We recommend AGO-Bs be placed at fixed sites, cleared and processed once a week to monitor mosquito abundance within a known infestation area. Long-term high density placements of AGO-Bs were found to show promise as an environmentally friendly trap-kill control strategy. California Ae. aegypti were found to be homozygous for the V1016I mutation in the voltage gated sodium channel gene, which is implicated to be involved in insecticide resistance. This strain originating from Clovis, California was resistant to some pyrethroids but not to deltamethrin in bottle bio-assays. Sentinel cage ultra-low-volume (ULV trials using a new formulation of deltamethrin (DeltaGard® demonstrated that it provided some control (average of 56% death in sentinel cages in a 91.4 m spray swath after a single truck mounted aerial ULV application in residential areas.
传疟按蚊抗药性研究进展%Research advance on insecticide resistance of malaria vector mosquito Anopheles
Institute of Scientific and Technical Information of China (English)
秦茜; 闫桂云; 陈晓光
In May 2010,the Ministry of Health and Chinese Government issued Action Plan of China Malaria Elimination (2010-2020),aiming at complete elimination of malaria in P.R.China by 2020.Vector control is a fundamental element of the existing global strategy to fight malaria.Anopheles is the main malaria vector mosquito.However,rapidly increasing insecticide resistance of mosquitoes threatens current malaria vector control efforts.In order to understand current status of mosquito resistance to insecticide and resistance mechanisms of the malaria vector,the current status of insecticide resistance in malaria vector mosquito Anopheles,the resistance mechanisms and the detection methods on resistance were reviewed in this paper.%我国卫生部于2010年5月印发《中国消除疟疾行动计划(2010-2020年)》,提出在2020年,将全面彻底消除疟疾.控制及消除疟疾的关键在于传播媒介的控制,而按蚊为疟疾主要传播媒介,传疟媒介对杀虫剂的抗药性直接导致了疟疾发病的死灰复燃.为了全面了解疟疾蚊媒的抗药性现状和产生机制,该文对国内外传疟按蚊抗药性现状、产生机制和检测方法进行综述.
Effect of isodillapiole on the expression of the insecticide resistance genes GSTE7 and CYP6N12 in Aedes aegypti from central Amazonia.
Lima, V S; Pinto, A C; Rafael, M S
The yellow fever mosquito Aedes (Stegomyia) aegypti is the main vector of dengue arbovirus and other arboviruses. Dengue prevention measures for the control of A. aegypti involve mainly the use of synthetic insecticides. The constant use of insecticides has caused resistance in this mosquito. Alternative studies on plant extracts and their products have been conducted with the aim of controlling the spread of the mosquito. Dillapiole is a compound found in essential oils of the plant Piper aduncum (Piperaceae) which has been effective as a biopesticide against A. aegypti. Isodillapiole is a semisynthetic substance obtained by the isomerization of dillapiole. In the present study, isodillapiole was evaluated for its potential to induce differential expression of insecticide resistance genes (GSTE7 and CYP6N12) in 3rd instar larvae of A. aegypti. These larvae were exposed to this compound at two concentrations (20 and 40 μg/mL) for 4 h during four generations (G1, G2, G3, and G4). Quantitative RT-PCR was used to assess the expression of GSTE7 and CYP6N12 genes. GSTE7 and CYP6N12 relative expression levels were higher at 20 than at 40 μg/mL and varied among generations. The decrease in GSTE7 and CYP6N12 expression levels at the highest isodillapiole concentration suggests that larvae may have suffered from metabolic stress, revealing a potential alternative product in the control of A. aegypti.
抗高效氯氰菊酯家蝇品系对几种杀虫剂的交互抗性%Cross resistance of beta-cypermethrin resistant Musca domestica strains to several kinds of insecticides
Institute of Scientific and Technical Information of China (English)
陈德国; 霍新北
Objective To explore the beta-cypermethrin resistance Musca domestica strains development and cross resistance to the other three insecticides, and supply evidence for using insecticides reasonably. Methods Topical application method was used. Results The resistance ratio of Musca domestica to beta-cypermethrin increased to 152.907 9 times after 26 generations' selection, and the ratio of cross resistance to deltamethrin was 44.819 6,there was significant cross resistance, multiple resistance to DDVP was 8.789 9, cross resistance was not obvious,multiple cross resistance to propoxur was 0.607 4 with negative cross resistance. Conclusion Long-term use of the same insecticide will result in resistance and also cross resistance to other insecticides. It is necessary to pay attention to the choice of insecticide kinds.%目的 探讨家蝇高效氯氰菊酯抗性品系抗性的发展及对其他3种杀虫剂交互抗性,为合理使用杀虫剂提供依据.方法 采用微量点滴法.结果 经过26代的选育,抗高效氯氰菊酯家蝇品系的抗性倍数达152.9079,对溴氰菊酯的交互抗性倍数为44.8196,有明显的交互抗性,对DDVP抗性倍数8.7899,交互抗性不明显,对残杀威的交互抗性倍数0.6074,呈负交互抗性.结论 长期使用同一种杀虫剂易产生抗性,对其他杀虫剂也会产生交互抗性,使用杀虫剂时应注意种类的选择.
Impact of Insecticide Resistance on the Effectiveness of Pyrethroid-Based Malaria Vectors Control Tools in Benin: Decreased Toxicity and Repellent Effect.
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Fiacre R Agossa
Full Text Available Since the first evidence of pyrethroids resistance in 1999 in Benin, mutations have rapidly increased in mosquitoes and it is now difficult to design a study including a control area where malaria vectors are fully susceptible. Few studies have assessed the after effect of resistance on the success of pyrethroid based prevention methods in mosquito populations. We therefore assessed the impact of resistance on the effectiveness of pyrethroids based indoor residual spraying (IRS in semi-field conditions and long lasting insecticidal nets (LLINs in laboratory conditions. The results observed showed low repulsion and low toxicity of pyrethroids compounds in the test populations. The toxicity of pyrethroids used in IRS was significantly low with An. gambiae s.l (< 46% but high for other predominant species such as Mansonia africana (93% to 97%. There were significant differences in terms of the repellent effect expressed as exophily and deterrence compared to the untreated huts (P<0.001. Furthermore, mortality was 23.71% for OlyseNet® and 39.06% for PermaNet®. However, with laboratory susceptible "Kisumu", mortality was 100% for both nets suggesting a resistance within the wild mosquito populations. Thus treatment with pyrethroids at World Health Organization recommended dose will not be effective at reducing malaria in the coming years. Therefore it is necessary to study how insecticide resistance decreases the efficacy of particular pyrethroids used in pyrethroid-based vector control so that a targeted approach can be adopted.
Methods for monitoring the resistance of whiteflies and thrips to insecticides%粉虱和蓟马类害虫的抗药性监测方法
Institute of Scientific and Technical Information of China (English)
吴青君; 徐宝云; 谢文; 王少丽; 张友军
粉虱和蓟马类害虫是我国经济作物上的主要害虫,为害呈逐年加重趋势,其抗药性也是生产中的主要问题.抗药性水平监测是害虫抗性早期预警和治理的基础,了解害虫抗药性水平须建立一套准确易于操作的监测方法.分别针对粉虱成虫和蓟马的琼脂保湿浸叶法和叶管药膜法的最大特点是快速、便于操作,接虫前的准备工作可以提前1-2d完成,可监测当代试虫的抗性水平,结果更接近于田间实际,适合在粉虱和蓟马抗性监测中推广使用.%Whiteflies and thrips are major insect pests that cause serious crop damage each year. Insecticide resistance is a major obstacle to the effective control of these pests. Monitoring insecticide resistance is a key step for early warning and resistance management which requires an accurate and convenient methodology. The main benefits of the agar leaf-dipping method for whitefly adults and the leaf tube residue method for thrips are that they are quick and easy to operate. Preparatory work can be completed one or two days ahead of introducing the insects. Also, both methods can monitor the resistance level of the F0 generation, which is closer to the field situation. These two methods are therefore suitable for promotion for use in monitoring insecticide resistance in whitefly and thrips.
Anopheles gambiae distribution and insecticide resistance in the cities of Douala and Yaoundé (Cameroon: influence of urban agriculture and pollution
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Awono-Ambene Parfait
Full Text Available Abstract Background Urban malaria is becoming a major health priority across Africa. A study was undertaken to assess the importance of urban pollution and agriculture practice on the distribution and susceptibility to insecticide of malaria vectors in the two main cities in Cameroon. Methods Anopheline larval breeding sites were surveyed and water samples analysed monthly from October 2009 to December 2010. Parameters analysed included turbidity, pH, temperature, conductivity, sulfates, phosphates, nitrates, nitrites, ammonia, aluminium, alkalinity, iron, potassium, manganese, magnesium, magnesium hardness and total hardness. Characteristics of water bodies in urban areas were compared to rural areas and between urban sites. The level of susceptibility of Anopheles gambiae to 4% DDT, 0.75% permethrin, 0.05% deltamethrin, 0.1% bendiocarb and 5% malathion were compared between mosquitoes collected from polluted, non polluted and cultivated areas. Results A total of 1,546 breeding sites, 690 in Yaoundé and 856 in Douala, were sampled in the course of the study. Almost all measured parameters had a concentration of 2- to 100-fold higher in urban compare to rural breeding sites. No resistance to malathion was detected, but bendiocarb resistance was present in Yaounde. Very low mortality rates were observed following DDT or permethrin exposure, associated with high kdr frequencies. Mosquitoes collected in cultivated areas, exhibited the highest resistant levels. There was little difference in insecticide resistance or kdr allele frequency in mosquitoes collected from polluted versus non-polluted sites. Conclusion The data confirm high selection pressure on mosquitoes originating from urban areas and suggest urban agriculture rather than pollution as the major factor driving resistance to insecticide.
Influence of insecticide Bacillus thuringiensis subsp. israelensis treatments on resistance and enzyme activities in Aedes rusticus larvae (Diptera : Culicidae)
Boyer, Sébastien; M. Paris(LANL); JEGO S.; Lempérière, Guy; Ravanel, P.
The bacterio-insecticide Bacillus thuringiensis subsp. israelensis (Bti) represents currently a safe alternative to chemical insecticides in mosquito-borne diseases control and is intensively used worldwide. In the French Rhone-alpine mosquito Aedes rusticus Rossi, several genomic signatures of selection were detected in populations treated for more than 15 years with Bti. In this study we investigated whether detoxifying enzyme activities such as cytochromes P450, esterases and glutathione S...
Acetylcholinesterase Inhibitors: Pharmacology and Toxicology
Čolović, Mirjana B.; Krstić, Danijela Z; Lazarević-Pašti, Tamara D; Bondžić, Aleksandra M; Vasić, Vesna M
Acetylcholinesterase is involved in the termination of impulse transmission by rapid hydrolysis of the neurotransmitter acetylcholine in numerous cholinergic pathways in the central and peripheral nervous systems. The enzyme inactivation, induced by various inhibitors, leads to acetylcholine accumulation, hyperstimulation of nicotinic and muscarinic receptors, and disrupted neurotransmission. Hence, acetylcholinesterase inhibitors, interacting with the enzyme as their primary target, are appl...
The impact of pyrethroid resistance on the efficacy of insecticide-treated bed nets against African anopheline mosquitoes: systematic review and meta-analysis.
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Clare Strode
Full Text Available Pyrethroid insecticide-treated bed nets (ITNs help contribute to reducing malaria deaths in Africa, but their efficacy is threatened by insecticide resistance in some malaria mosquito vectors. We therefore assessed the evidence that resistance is attenuating the effect of ITNs on entomological outcomes.We included laboratory and field studies of African malaria vectors that measured resistance at the time of the study and used World Health Organization-recommended impregnation regimens. We reported mosquito mortality, blood feeding, induced exophily (premature exit of mosquitoes from the hut, deterrence, time to 50% or 95% knock-down, and percentage knock-down at 60 min. Publications were searched from 1 January 1980 to 31 December 2013 using MEDLINE, Cochrane Central Register of Controlled Trials, Science Citation Index Expanded, Social Sciences Citation Index, African Index Medicus, and CAB Abstracts. We stratified studies into three levels of insecticide resistance, and ITNs were compared with untreated bed nets (UTNs using the risk difference (RD. Heterogeneity was explored visually and statistically. Included were 36 laboratory and 24 field studies, reported in 25 records. Studies tested and reported resistance inconsistently. Based on the meta-analytic results, the difference in mosquito mortality risk for ITNs compared to UTNs was lower in higher resistance categories. However, mortality risk was significantly higher for ITNs compared to UTNs regardless of resistance. For cone tests: low resistance, risk difference (RD 0.86 (95% CI 0.72 to 1.01; moderate resistance, RD 0.71 (95% CI 0.53 to 0.88; high resistance, RD 0.56 (95% CI 0.17 to 0.95. For tunnel tests: low resistance, RD 0.74 (95% CI 0.61 to 0.87; moderate resistance, RD 0.50 (95% CI 0.40 to 0.60; high resistance, RD 0.39 (95% CI 0.24 to 0.54. For hut studies: low resistance, RD 0.56 (95% CI 0.43 to 0.68; moderate resistance, RD 0.39 (95% CI 0.16 to 0.61; high resistance, RD 0
北京西城区家蝇抗药性调查研究%Insecticide resistance of Musca domestica in Xicheng district of Beijing
Institute of Scientific and Technical Information of China (English)
申同洋; 秦迪; 杜晓旭; 赵秀英; 王晓军
目的 探讨家蝇抗药性状况及防治对策.方法 药膜法.结果 西城区家蝇对高效氯氰菊酯、残杀威的抗药系数为125.4和1194.3.结论 家蝇在西城区对高效氯氰菊酯、残杀威达到了高等抗药水平,应停止使用残杀威药物灭蝇,高效氯氰菊酯类药物应与其他药物交替使用,以达到更好的防治效果.%Objective To survey the insecticide resistance of Musca domestica and discuss its control strategy. Methods Using the method of residual film. Rusults The resistance to Beta-cypermethrin was 125.4 folds;the resistance to propoxur was 1194.3 folds. Conclusion The resistance of Musca domestica to Beta-cypermethrin and propoxur is high in Xicheng district. It is necessary to stop using propoxur. Beta-cypermethrin should be used alternately with other insecticides.
Metabolism of methoxychlor by the P450-monooxygenase CYP6G1 involved in insecticide resistance of Drosophila melanogaster after expression in cell cultures of Nicotiana tabacum.
Joussen, Nicole; Schuphan, Ingolf; Schmidt, Burkhard
Cytochrome P450 monooxygenase CYP6G1 of Drosophila melanogaster was heterologously expressed in a cell suspension culture of Nicotiana tabacum. This in vitro system was used to study the capability of CYP6G1 to metabolize the insecticide methoxychlor (=1,1,1-trichloro-2,2-bis(4-methoxyphenyl)ethane, 1) against the background of endogenous enzymes of the corresponding non-transgenic culture. The Cyp6g1-transgenic cell culture metabolized 96% of applied methoxychlor (45.8 microg per assay) within 24 h by demethylation and hydroxylation mainly to trishydroxy and catechol methoxychlor (16 and 17%, resp.). About 34% of the metabolism and the distinct formation of trishydroxy and catechol methoxychlor were due to foreign enzyme CYP6G1. Furthermore, methoxychlor metabolism was inhibited by 43% after simultaneous addition of piperonyl butoxide (458 microg), whereas inhibition in the non-transgenic culture amounted to 92%. Additionally, the rate of glycosylation was reduced in both cultures. These results were supported by the inhibition of the metabolism of the insecticide imidacloprid (6; 20 microg, 24 h) in the Cyp6g1-transgenic culture by 82% in the presence of piperonyl butoxide (200 microg). Due to CYP6G1 being responsible for imidacloprid resistance of Drosophila or being involved in DDT resistance, it is likely that CYP6G1 conveys resistance to methoxychlor (1). Furthermore, treating Drosophila with piperonyl butoxide could weaken the observed resistance phenomena.
Research Progress on Mechanism of Insect Resistance to Insecticides%昆虫抗药性机制研究进展
Institute of Scientific and Technical Information of China (English)
阮成龙; 米智; 朱勇
由于杀虫剂的长期使用,昆虫产生的抗药性已成为农林虫害治理面临的重大问题.研究昆虫抗药性机制有助于为农林害虫防控、资源昆虫抗性品系选育及新型杀虫剂研发提供科学指导.长期以来,人们通过对模式昆虫、卫生昆虫和农林害虫的研究,对昆虫的代谢抗性、靶标抗性有了一定认识,继而利用分子生物学手段克隆、分析了一些抗性相关基因,目前正从基因组学角度去深入阐明昆虫抗药性机制.结合近年来的研究成果,由昆虫抗药性涉及的主要解毒酶入手,对昆虫抗药性形成的生理生化及分子生物学机制作一综述.%Drug resistance in insects has become a major problem faced by pest control in agriculture and forestry due to long term use of insecticides.Studies on insect resistance mechanism could provide scientific guidance for prevention and control of agricultural and forestry pests,selection and breeding of resistant strains in resource insect,and exploitation of novel insecticides.Primary understanding on the metabolic resistance and target-site resistance has been obtained through studying the model insects,medical insects,agricultural and forestry pests.And a number of genes related to drug resistance have been cloned and analyzed using molecular biological methods.At present,further research is being conducted to elucidate mechanism of insect resistance to insecticides in view of genomics.Based on the research achievements of recent years,this article summarizes physiological,biochemical,and molecular mechanisms contributing to the formation of drug resistance with emphasis on analyzing the major detoxification enzymes involved in drug resistance.
苹果蠹蛾抗药性研究进展%Research advances concerning insecticide resistance in the codling moth, Cydia pomonella (L.)
Institute of Scientific and Technical Information of China (English)
段辛乐; 乔宪凤; 陈茂华
苹果蠹蛾是世界各国高度关注的严重危害苹果生产的外来有害生物。该虫于20世纪50年代在我国首次报道,目前是我国一类进境检疫性有害生物,正严重威胁我国苹果主产区的水果生产安全。苹果蠹蛾以幼虫钻蛀到果实内部为害,防治难度高,对其主要采用化学农药、交配干扰和苹果蠹蛾颗粒体病毒进行防治。由于农药的长期大量使用,苹果蠹蛾已对有机磷、氨基甲酸酯、拟除虫菊酯、昆虫生长调节剂、阿维菌素和苹果蠹蛾颗粒体病毒等不同类型的杀虫剂产生了抗药性。本文总结了国内外有关苹果蠹蛾抗药性现状和抗药性机理方面的研究,并分析了其对几种农药产生抗性的主要原因,同时结合国外苹果蠹蛾防治和抗药性相关研究,以及其在我国发生与防治的现状,提出该虫抗药性治理策略,即及时对我国疫区苹果蠹蛾的抗药性现状进行监测,在此基础上,注意科学地使用化学农药,并结合农业防治和生物防治等措施对该虫进行综合治理。%The codling moth, Cydia pomonella, is one of the most important pest insects in fruit orchards worldwide as well as an important invasive species in different regions of the world.In China, C.pomonella was first reported in the 1950ie-s and was consid-ered a serious invasive species, threatening the safety of fruit production.As the larvae of codling moth bear into the fruit, it is diffi-cult to control this pest.Chemical insecticides, mating disruption and the virus CpGV were the main control methods.In different re-gions of the world, C.pomonella had developed resistance to different types of insecticides including organophosphates, carbamates, pyrethroids, insect growth regulators, abamectin and CpGV.In this paper, the status of insecticide resistance, knowledge on the de-velopment insecticide resistance, the resistance mechanisms and the main reasons causing
Push-pull Strategy with Trap Crops, Neem and Nuclear Polyhedrosis Virus for Insecticide Resistance Management in Helicoverpa armigera (Hubner in Cotton
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P. Duraimurugan
Full Text Available Insecticide resistance in Helicoverpa armigera (Hubner is a major threat to cotton production in India. The virus infection was found to increase the susceptibility of H. armigera to the insecticides. But, use of Nuclear Polyhedrosis Virus (NPV on a larger scale and on cotton due to leaf alkalinity poses certain practical problems. Hence, studies were carried out to assess the effects of push-pull strategy with trap crops, neem and NPV in cotton for the management of insecticide resistant H. armigera. Field experiments were conducted on cotton (MCU5 with trap crops (okra and pigeonpea and neem was used to diversify the pests to trap crops whereby the control of these pests was assessed with the application of NPV. The preference of H. armigera was towards okra and pigeonpea as a trap crop compared to cotton. Application of NSKE on cotton diversified the H. armigera towards untreated okra and pigeonpea. Push-pull strategy with the conjunctive use of trap crops, restricted application of NSKE on cotton leaving trap crops and restricted application of NPV on trap crops was highly effective in reducing the incidence of H. armigera and damage to fruiting bodies, boll, locule and inter locule basis over cotton sole crop (untreated check. The percent recovery of NPV infected larvae varied from 37.5-47.5, 32.8-39.2 and 14.2-20.2% on okra, pigeon pea and cotton respectively. The synthetic pyrethroids resistance in field survived H. armigera at the end of the season was reduced from 87.5-93.1% to 76.4-84.3%.
The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa
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Howard Annabel FV
Full Text Available Abstract Background Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show that entomopathogenic fungi can kill insecticide-resistant malaria vectors but this needs to be verified in the field. Methods The present study investigated whether these fungi will be effective at infecting, killing and/or modifying the behaviour of wild multi-insecticide-resistant West African mosquitoes. The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were separately applied to white polyester window netting and used in combination with either a permethrin-treated or untreated bednet in an experimental hut trial. Untreated nets were used because we wanted to test the effect of fungus alone and in combination with an insecticide to examine any potential additive or synergistic effects. Results In total, 1125 female mosquitoes were collected during the hut trial, mainly Culex quinquefasciatus Say. Unfortunately, not enough wild Anopheles gambiae Giles were collected to allow the effect the fungi may have on this malaria vector to be analysed. None of the treatment combinations caused significantly increased mortality of Cx. quinquefasciatus when compared to the control hut. The only significant behaviour modification found was a reduction in blood feeding by Cx. quinquefasciatus, caused by the permethrin and B. bassiana treatments, although no additive effect was seen in the B. bassiana and permethrin combination treatment. Beauveria bassiana did not repel blood foraging mosquitoes either in the laboratory or field. Conclusions This is the first time that an entomopathogenic fungus has been shown to reduce blood feeding of wild mosquitoes. This behaviour modification indicates that B. bassiana could potentially be a new
Larvicidal activities of chinaberry, neem and Bacillus thuringiensis israelensis (Bti) to an insecticide resistant population of Anopheles arabiensis from Tolay, Southwest Ethiopia
Assalif Demissew; Meshesha Balkew; Melaku Girma
Objective: To elucidate the larvicidal potency of neem, chinaberry and Bacillus thuringiensis israelensis (Bti) to larvae of Anopheles arabiensis under semi-field condition and adult susceptibility/resistance to the conventionally used insecticides in Tolay, Southwestern Ethiopia. Methods: Wild collected 3rd and 4th stage larvae were exposed to neem, and chinaberry seed powder dissolved in water and Bti in artificial containers at three treatment levels: 0.2, 0.1 and 0.05 g/m2 and controls...
General Research Situation of Resistance of Target Insect to Bt Insecticidal Crystal Protein%目标昆虫对Bt杀虫晶体蛋白抗性的研究概况
Institute of Scientific and Technical Information of China (English)
杨宙; 康美花; 陈红萍; 刘建华; 曹丰生
This article summarized the resistance of many target insect species to Bt insecticidal crystal protein, and introduced the mechanism of generating resistance and its hereditary characters.%综述了多种目标昆虫对Bt杀虫晶体蛋白的抗性机制和遗传特性.
Binding site alteration is responsible for field-isolated resistance to Bacillus thuringiensis Cry2A insecticidal proteins in two Helicoverpa species.
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Silvia Caccia
Full Text Available BACKGROUND: Evolution of resistance by target pests is the main threat to the long-term efficacy of crops expressing Bacillus thuringiensis (Bt insecticidal proteins. Cry2 proteins play a pivotal role in current Bt spray formulations and transgenic crops and they complement Cry1A proteins because of their different mode of action. Their presence is critical in the control of those lepidopteran species, such as Helicoverpa spp., which are not highly susceptible to Cry1A proteins. In Australia, a transgenic variety of cotton expressing Cry1Ac and Cry2Ab (Bollgard II comprises at least 80% of the total cotton area. Prior to the widespread adoption of Bollgard II, the frequency of alleles conferring resistance to Cry2Ab in field populations of Helicoverpa armigera and Helicoverpa punctigera was significantly higher than anticipated. Colonies established from survivors of F(2 screens against Cry2Ab are highly resistant to this toxin, but susceptible to Cry1Ac. METHODOLOGY/PRINCIPAL FINDINGS: Bioassays performed with surface-treated artificial diet on neonates of H. armigera and H. punctigera showed that Cry2Ab resistant insects were cross-resistant to Cry2Ae while susceptible to Cry1Ab. Binding analyses with (125I-labeled Cry2Ab were performed with brush border membrane vesicles from midguts of Cry2Ab susceptible and resistant insects. The results of the binding analyses correlated with bioassay data and demonstrated that resistant insects exhibited greatly reduced binding of Cry2Ab toxin to midgut receptors, whereas no change in (125I-labeled-Cry1Ac binding was detected. As previously demonstrated for H. armigera, Cry2Ab binding sites in H. punctigera were shown to be shared by Cry2Ae, which explains why an alteration of the shared binding site would lead to cross-resistance between the two Cry2A toxins. CONCLUSION/SIGNIFICANCE: This is the first time that a mechanism of resistance to the Cry2 class of insecticidal proteins has been reported
[Laboratory evaluation of alpha-cypermethrin insecticide efficacy on Anopheles gambiae populations of Côte d'Ivoire resistant to permethrin and deltamethrin].
Koffi, A A; Darriet, F; N'Guessan, R; Doannio, J M; Carnevale, P
Susceptibility tests were carried out in laboratory conditions to evaluate the efficacy of alpha-cypermethrin (a synthetic pyrethroid never used in Côte d'Ivoire) for malaria vector control. Five wild populations of Anopheles gambiae originating from M'bé, Yaokoffikro, Korhogo, Kafiné and Daola and two laboratory reared strains (Kisumu susceptible and Kou permethrin resistant selected strain) were tested. The diagnostic dosage of alpha-cypermethrin for the sensitive strain Kisumu was 2.5 x 10(-3)%. A comparative study of the susceptibility of samples of wild populations of An. gambiae was carried out according to the WHO standard susceptibility test. Impregnated papers with 4% DDT, 0.25% permethrin, 0.025% deltamethrin and 0.0025% alpha-cypermethrin were used. The results showed that except for mosquitoes from M'bé, all the other populations were resistant to these insecticides. Bioassays were carried out with alpha-cypermethrin at the operational dosage of 20 mg a.i./m2 on the same population and laboratory reared strains. The results showed the efficacy of this insecticide on both the Kisumu strain and the population from M'bé, a maintained efficacy for the Daloa, Kafiné and Korhogo mosquito populations, but the wild anopheline population from Yaokoffikro clearly appeared fully resistant.
Genetic divergence between two sympatric species of the Lutzomyia longipalpis complex in the paralytic gene, a locus associated with insecticide resistance and lovesong production
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RMMA Lins
Full Text Available The sandfly Lutzomyia longipalpis s.l. is the main vector of American Visceral Leishmaniasis. L. longipalpis s.l. is a species complex but until recently the existence of cryptic sibling species among Brazilian populations was a controversial issue. A fragment of paralytic (para, a voltage dependent sodium channel gene associated with insecticide resistance and courtship song production in Drosophila, was isolated and used as a molecular marker to study the divergence between two sympatric siblings of the L. longipalpis complex from Sobral, Brazil. The results revealed para as the first single locus DNA marker presenting fixed differences between the two species in this locality. In addition, two low frequency amino-acid changes in an otherwise very conserved region of the channel were observed, raising the possibility that it might be associated with incipient resistance in this vector. To the best of our knowledge, the present study represents the first population genetics analysis of insecticide resistance genes in this important leishmaniasis vector.
New developments in insecticide resistance in the glasshouse whitefly (Trialeurodes vaporariorum) and the two-spotted spider mite (Tetranychus urticae) in the UK.
Gorman, Kevin; Hewitt, Fiona; Denholm, Ian; Devine, Gregor J
A recent survey of insecticide resistance in two of the most problematic pests in UK glasshouses revealed some new developments. At least some individuals in all UK samples of Trialeurodes vaporariorum that were tested resisted the insect growth regulator (IGR) buprofezin. The most strongly resistant strains were unaffected by the field application rate of this compound, and even samples from populations that had never been exposed to buprofezin contained individuals that survived the highest concentration applied (10,000 mg litre-1). The field rate of buprofezin was shown to select for resistance through vapour action alone. The benzophenylurea teflubenzuron, an unrelated IGR, was cross-resisted by buprofezin-resistant individuals. There was no evidence of resistance to imidacloprid, but all T vaporariorum strains tested, regardless of origin, exhibited a high innate tolerance to nicotine, when compared with another whitefly species, Bemisia tabaci. Marked resistance to fenbutatin oxide and tebufenpyrad was found in single glasshouse populations of Tetranychus urticae, but these compounds and abamectin appeared to remain highly effective against all other strains collected.
Resistance of Blattella germanica to five kinds of insecticides%德国小蠊对5种杀虫剂的抗药性测定
Institute of Scientific and Technical Information of China (English)
侯威远; 蔡伟; 赵岩; 王磊
目的 了解海淀区现场品系德国小蠊对常用杀虫剂的抗性水平,为合理选择用药提供依据.方法 采用药膜接触法测定抗性水平.结果 现场品系德国小蠊对氯氰菊酯、溴氰菊酯、残杀威、乙酰甲胺磷和敌敌畏的抗性系数分别为7.03、3.20、2.90、7.57和>13.13.结论 海淀区德国小蠊对残杀威没有产生明显的抗药性,对溴氰菊酯产生了耐药性,而对氯氰菊酯、乙酰甲胺磷和敌敌畏产生了明显的抗药性.%Objective To determine the resistance of Blattella germanica to five commonly used insecticides in Haidian district and provide the evidence for rational insecticides selection. Methods The resistance was examined by the method of contacting with chemical cover. Results The resistance index of field collected strains to cypermethrin, deltamethrin, propoxur, acephate and dichlorvos were 7.03,3.20,2.90,7.57 and > 13. 13 respectively. Conclusion The field strain in Haidian district has no significant resistance to propoxur. However, it has developed low resistance to deltamethrin and high resistance to cypermethrin, acephate and dichlorvos.
Pinpointing P450s associated with pyrethroid metabolism in the dengue vector, Aedes aegypti: developing new tools to combat insecticide resistance.
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Bradley J Stevenson
Full Text Available BACKGROUND: Pyrethroids are increasingly used to block the transmission of diseases spread by Aedes aegypti such as dengue and yellow fever. However, insecticide resistance poses a serious threat, thus there is an urgent need to identify the genes and proteins associated with pyrethroid resistance in order to produce effective counter measures. In Ae. aegypti, overexpression of P450s such as the CYP9J32 gene have been linked with pyrethroid resistance. Our aim was to confirm the role of CYP9J32 and other P450s in insecticide metabolism in order to identify potential diagnostic resistance markers. METHODOLOGY/PRINCIPAL FINDINGS: We have expressed CYP9J32 in Escherichia coli and show that the enzyme can metabolize the pyrethroids permethrin and deltamethrin. In addition, three other Ae. aegypti P450s (CYP9J24, CYP9J26, CYP9J28 were found capable of pyrethroid metabolism, albeit with lower activity. Both Ae. aegypti and Anopheles gambiae P450s (CYP's 6M2, 6Z2, 6P3 were screened against fluorogenic and luminescent substrates to identify potential diagnostic probes for P450 activity. Luciferin-PPXE was preferentially metabolised by the three major pyrethroid metabolisers (CYP9J32, CYP6M2 and CYP6P3, identifying a potential diagnostic substrate for these P450s. CONCLUSIONS/SIGNIFICANCE: P450s have been identified with the potential to confer pyrethroid resistance in Ae.aegypti. It is recommended that over expression of these enzymes should be monitored as indicators of resistance where pyrethroids are used.
Anticholinesterase insecticide retrospective.
Casida, John E; Durkin, Kathleen A
The anticholinesterase (antiChE) organophosphorus (OP) and methylcarbamate (MC) insecticides have been used very effectively as contact and systemic plant protectants for seven decades. About 90 of these compounds are still in use - the largest number for any insecticide chemotype or mode of action. In both insects and mammals, AChE inhibition and acetylcholine accumulation leads to excitation and death. The cholinergic system of insects is located centrally (where it is protected from ionized OPs and MCs) but not at the neuromuscular junction. Structural differences between insect and mammalian AChE are also evident in their genomics, amino acid sequences and active site conformations. Species selectivity is determined in part by inhibitor and target site specificity. Pest population selection with OPs and MCs has resulted in a multitude of modified AChEs of altered inhibitor specificity some conferring insecticide resistance and others enhancing sensitivity. Much of the success of antiChE insecticides results from a suitable balance of bioactivation and detoxification by families of CYP450 oxidases, hydrolases, glutathione S-transferases and others. Known inhibitors for these enzymes block detoxification and enhance potency which is particularly important in resistant strains. The current market for OPs and MCs of 19% of worldwide insecticide sales is only half of that of 10 years ago for several reasons: there have been no major new compounds for 30 years; resistance has eroded their effectiveness; human toxicity problems are still encountered; the patents have expired reducing the incentive to update registration packages; alternative chemotypes or control methods have been developed. Despite this decline, they still play a major role in pest control and the increasing knowledge on their target sites and metabolism may make it possible to redesign the inhibitors for insensitive AChEs and to target new sites in the cholinergic system. The OPs and MCs are down
鄂尔多斯市家蝇抗药性调查分析%Insecticide resistance in Musca domestica in Ordos
Institute of Scientific and Technical Information of China (English)
王玲芳; 海玉和; 白长义; 高慧; 蔺权德
Objective To determine current resistance to commonly used insecticides in the natural population of Musca domestica in Ordos city, in order to evidence for proper application of insecticides for fly control. Methods Topical application method was used in the study. Results The natural populations of M. Domestica in Ordos city had developed various degrees of resistances to dichlorovos, deltamethrin and beta-cypermethrin, with resistance ratios of 19.39, 48.05, and 407.69, respectively. Propoxur resulted in low fatality in M. Domestica. Conclusion The natural populations of M. Domestica in Ordos city had low resistance to dichlorovos and high resistance to deltamethrin and beta-cypermethrin. Propoxur had a low lethality rate in the flies.%目的 了解鄂尔多斯市近年来家蝇自然种群对常用卫生杀虫剂的抗药性现状,为合理使用杀虫剂和指导灭蝇工作提供依据.方法 采用微量点滴法.结果 鄂尔多斯市家蝇自然种群对敌敌畏、溴氰菊酯、高效氯氰菊酯已呈现出不同程度的抗药性,抗性倍数依次为19.39、48.05和407.69倍,残杀威对家蝇的致死率较低.结论 鄂尔多斯市家蝇自然种群对敌敌畏的抗药性较低,对溴氰菊酯和高效氯氰菊酯呈现高抗水平,对残杀威致死率较低.
Pilot study on the combination of an organophosphate-based insecticide paint and pyrethroid-treated long lasting nets against pyrethroid resistant malaria vectors in Burkina Faso.
Mosqueira, Beatriz; Soma, Dieudonné D; Namountougou, Moussa; Poda, Serge; Diabaté, Abdoulaye; Ali, Ouari; Fournet, Florence; Baldet, Thierry; Carnevale, Pierre; Dabiré, Roch K; Mas-Coma, Santiago
A pilot study to test the efficacy of combining an organophosphate-based insecticide paint and pyrethroid-treated Long Lasting Insecticide Treated Nets (LLINs) against pyrethroid-resistant malaria vector mosquitoes was performed in a real village setting in Burkina Faso. Paint Inesfly 5A IGR™, comprised of two organophosphates (OPs) and an Insect Growth Regulator (IGR), was tested in combination with pyrethroid-treated LLINs. Efficacy was assessed in terms of mortality for 12 months using Early Morning Collections of malaria vectors and 30-minute WHO bioassays. Resistance to pyrethroids and OPs was assessed by detecting the frequency of L1014F and L1014S kdr mutations and Ace-1(R)G119S mutation, respectively. Blood meal origin was identified using a direct enzyme-linked immunosorbent assay (ELISA). The combination of Inesfly 5A IGR™ and LLINs was effective in killing 99.9-100% of malaria vector populations for 6 months regardless of the dose and volume treated. After 12 months, mortality rates decreased to 69.5-82.2%. The highest mortality rates observed in houses treated with 2 layers of insecticide paint and a larger volume. WHO bioassays supported these results: mortalities were 98.8-100% for 6 months and decreased after 12 months to 81.7-97.0%. Mortality rates in control houses with LLINs were low. Collected malaria vectors consisted exclusively of Anopheles coluzzii and were resistant to pyrethroids, with a L1014 kdr mutation frequency ranging from 60 to 98% through the study. About 58% of An. coluzzii collected inside houses had bloodfed on non-human animals. Combining Inesfly 5A IGR™ and LLINs yielded a one year killing efficacy against An. coluzzii highly resistant to pyrethroids but susceptible to OPs that exhibited an anthropo-zoophilic behaviour in the study area. The results obtained in a real setting supported previous work performed in experimental huts and underscore the need to study the impact that this novel strategy may have on clinical
Generation of insect-resistant and glyphosate-tolerant rice by introduction of a T-DNA containing two Bt insecticidal genes and an EPSPS gene.
Zhao, Qi-chao; Liu, Ming-hong; Zhang, Xian-wen; Lin, Chao-yang; Zhang, Qing; Shen, Zhi-cheng
Insect resistance and glyphosate tolerance have been two of the most important traits in the genetic improvement of various crops. In this study, two Bacillus thuringiensis (Bt) insecticidal genes, Cry1Ac and Cry1Ig, and a modified glyphosate-tolerant 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene (G10) were combined into a single transferred DNA (T-DNA) fragment and introduced into rice by Agrobacterium-mediated transformation. A transgenic line with single-copy T-DNA insertion named GAI-14 was found to be highly resistant to striped stem borer and rice leaf roller, and tolerant to glyphosate. Analysis of T-DNA border sequence suggested that the transgenes were inserted at the chromosome 3 and appeared to have not interrupted any known or putative genes. A field trial observed no significant difference in the basic agronomic traits between GAI-14 and the recipient rice.
Current status and management strategies of insecticide resistance in aphids on the vegetable crops%蔬菜蚜虫抗药性现状及抗性治理策略
Institute of Scientific and Technical Information of China (English)
汤秋玲; 马康生; 高希武
Vegetables are important economic crops and the aphids are a group of important insect pests that cause great losses in vegetable production.The application of insecticides is an important means for controlling the aphids on vegetable crops.However,because of irrational application of insecticides,many aphid species on vege-table crops have developed strong resistance to most of commonly used insecticides,such as organophosphate,py-rethroid,carbamate and neonicotinoid insecticides.In the present review,the current status of insecticide resist-ance and resistance mechanisms of aphids on vegetable crops were reviewed.In addition,the strategies for insecti-cides resistance management in these aphids were summarized.The review could provide useful information for the sustainable control of aphid pests on vegetable crops.%蚜虫是为害蔬菜作物的一类重要害虫,如不防治会给蔬菜生产造成重大经济损失。长期以来主要依靠使用农药防治蔬菜蚜虫,但由于化学农药的不合理使用,蔬菜蚜虫对有机磷、拟除虫菊酯、氨基甲酸酯、新烟碱等多种类型的杀虫药剂均产生了不同程度的抗性。本文对常见的蔬菜蚜虫的抗药性现状、抗药性机理以及治理策略进行了论述,以期为该类害虫的可持续控制提供参考。
Resistance detection of Musca domestica in various habitats with the method of acetylcholinesterase%乙酰胆碱酯酶用于不同生境家蝇抗药性研究
Institute of Scientific and Technical Information of China (English)
陶卉英; 马红梅; 柳小青; 陈海婴; 熊志伟; 郭学俭; 李卫民
Objective To detect the resistance of Musca domestics in various habitats in early phase with the method of acetylcholinesterase. Methods The traditional assay method and acetylcholinesterase were used to detect the resistance of M. domestica in various habitats to dichlorvos (DDVP) and propoxur. Results The bioassay results showed that 4 strains of M. domestics in the residential areas, restaurants, refuse transfer stations and agricultural fair had different resistance to DDVP, and the resistance ratio were 34.07, 22.57,20.05 and 17.43, respectively. The resistance ratio to propoxur was 2.68, 3.48, 2.15 and 2.74, respectively. The DDVP-resistanee individual rates of 4 strains in the residential areas, restaurants, refuse transfer stations and agricultural fair were 100%, 82%, 55% and 29%, while propoxur-resistant individual rates of them were 28%, 42%, 12% and 27%, respectively. Except for the strain in refuse transfer stations, the others had resistance to DDVP and propoxur. Conclusion The detection results of acetylcholinesterase were basically consistent with that of bioaasays, and it could be used to the early detection of resistance. The 4 resistant strains had middle or high resistance to DDVP and low resistance to propoxur. So, DDVP should be inhibited, and the mixed and rotational use measure could be taken to avoid and delay the development of resistance.%目的 应用一种家蝇抗药性早期检测方法即乙酰胆碱酯酶(AChE)法,了解南昌市不同生境家蝇对常用的有机磷和氨基甲酸酯类杀虫剂的抗性现状及其发展趋势.方法 采用微量点滴法进行生物测定,同时采用AChE检测不同生境家蝇对敌敌畏和残杀威的抗性水平.结果 生物测定结果表明,居民区、餐饮店、垃圾中转站和农贸市场4个家蝇品系对敌敌晨和残杀威产生了不同程度的抗性,对敌敌畏的抗性指数依次为34.07、22.57、20.05、17.43倍,其中农贸市场品系为中抗水平,其余3个品�
Culex pipiens pallens resistance to eight insecticides in Shaanxi province%陕西省淡色库蚊抗药性研究
Institute of Scientific and Technical Information of China (English)
孙养信; 吕文; 佘建军; 霍丽霞
目的 了解陕西省不同地区淡色库蚊对常用杀虫剂的抗性水平.方法 采用区分剂量法测定淡色库蚊幼虫对4种杀虫剂的24h死亡率;采用半数致死浓度(LC50)法测定淡色库蚊幼虫对8种杀虫剂的LC50.结果 区分剂量法测定结果显示,除榆林市淡色库蚊对氯菊酯属初步抗性群体外,其余均为抗性群体;LC50测定结果显示,5个市的淡色库蚊对高效氯氰菊酯、氯菊酯、溴氰菊酯、氯氰菊酯、DDT、DDVP、双硫磷、残杀威的LC5o分别为0.001 82~0.012 24、0.008 16~0.094 19、0.000 58~0.005 59、0.002 76~0.020 17、0.100 96~1.296 86、0.144 11~0.512 40、0.001 47~0.007 06、0.234 60~1.182 37 mg/L.宝鸡市淡色库蚊的抗药性普遍较高,除溴氰菊酯、氯氰菊酯、双硫磷3种药剂外,其余抗性倍数均在全省最高,而榆林市淡色库蚊的抗药性则普遍较低,除双硫磷和残杀威外,其余各药抗性倍数均为全省最低.结论 蚊虫抗药性的产生与杀虫剂的使用密切相关,在创建卫生城市、卫生县城工作中要科学合理用药,开展抗药性监测,以减缓蚊虫抗药性的产生.%Objective To evaluate the resistance in Culex pipiens pollens to commonly used insecticides in different areas of Shaanxi province. Methods Larval mortality for 4 insecticides and LC? Of 8 insecticides determined via the dosing method and median lethal dose method, respectively. Results The resistance level of Cx. Pipiens pollens in all five areas was high except the population in Yulin city, which had elementary resistance to permethrin. The LC? Values for larvae to p - cypermethrin, permethrin, deltamethrin, cypermethrin, DDT, DDVP, parathion and propoxur were 0.001 82-0.012 24, 0.008 16-0.094 19, 0.000 58-0.005 59, 0.002 76-0.020 17, 0.100 96-1.296 86, 0.144 11-0.512 40, 0.001 47-0.007 06, and 0.234 60-1.182 37 mg/L, respectively. The highest resistance level to all pesticides was found in Baoji city, except for
Larvicidal activities of chinaberry, neem and Bacillus thuringiensis israelensis (Bti) to an insecticide resistant population of Anopheles arabiensis from Tolay, Southwest Ethiopia
Institute of Scientific and Technical Information of China (English)
Assalif Demissew; Meshesha Balkew; Melaku Girma
Objective: To elucidate the larvicidal potency of neem, chinaberry and Bacillus thur-ingiensis israelensis (Bti) to larvae of Anopheles arabiensis under semi-field condition and adult susceptibility/resistance to the conventionally used insecticides in Tolay, Southwestern Ethiopia. Methods: Wild collected 3rd and 4th stage larvae were exposed to neem, and chinaberry seed powder dissolved in water and Bti in artificial containers at three treatment levels:0.2, 0.1 and 0.05 g/m2 and controls were free of treatments. Larval and pupal mortalities were monitored daily and residual activities were determined. The experiments were replicated three times. The World Health Organization tube test for all classes of in-secticides was conducted on adult Anopheles arabiensis reared from field collected larvae and pupae. Data were analyzed using STATA software version 11. Results: In the first application, neem powder caused 88.9%, 87.9%and 79.4%larval and pupal mortality at 0.2, 0.1 and 0.05 g/m2 after 4.3, 6.0 and 5.7 days, respectively. The cor-responding killing effect of chinaberry was 80.3%, 62.1%and 30.3%after 7.0, 7.7 and 8.3 days respectively. Bti at all treatments killed 100%after 24 h except 2.7 days for 0.05 g/m2. Adult mosquitoes were susceptible only for fenitrothion and pirimiphos-methyl with 100%mortality while resistant to deltamethrin, alpha-cypermethrin, etofenprox and dichloro-diphenyl-tricgloroethane with only 9.0%, 3.0%, 5.1%and 2.0%mortalities respectively. Conclusions: Neem, chinaberry and Bti showed potent larvicidal and pupicidal activ-ities. However, in the area, high level of mosquito resistance to pyrethroids and dichloro-diphenyl-tricgloroethane was seen which will pose serious challenge to vector control in the future. Therefore, using integrated approach including these botanical larvicides is warranted to manage insecticide resistance.
Larvicidal activities of chinaberry,neem and Bacillus thuringiensis israelensis(Bti) to an insecticide resistant population of Anopheles arabiensis from Tolay,Southwest Ethiopia
Institute of Scientific and Technical Information of China (English)
Assalif Demissew; Meshesha Balkew; Melaku Girma
Objective:To elucidate the larvicidal potency of neem, chinaberry and Bacillus thuringiensis israelensis(Bti) to larvae of Anopheles arabiensis under semi-field condition and adult susceptibility/resistance to the conventionally used insecticides in Tolay,Southwestern Ethiopia.Methods: Wild collected 3rd and 4th stage larvae were exposed to neem, and chinaberry seed powder dissolved in water and Bti in artificial containers at three treatment levels:0.2, 0.1 and 0.05 g/m~2 and controls were free of treatments. Larval and pupal mortalities were monitored daily and residual activities were determined. The experiments were replicated three times. The World Health Organization tube test for all classes of insecticides was conducted on adult Anopheles arabiensis reared from field collected larvae and pupae. Data were analyzed using STATA software version 11.Results: In the first application, neem powder caused 88.9%, 87.9% and 79.4% larval and pupal mortality at 0.2, 0.1 and 0.05 g/m~2 after 4.3, 6.0 and 5.7 days, respectively. The corresponding killing effect of chinaberry was 80.3%, 62.1% and 30.3% after 7.0, 7.7 and 8.3days respectively. Bti at all treatments killed 100% after 24 h except 2.7 days for 0.05 g/m~2.Adult mosquitoes were susceptible only for fenitrothion and pirimiphos-methyl with 100%mortality while resistant to deltamethrin, alpha-cypermethrin, etofenprox and dichlorodiphenyl-tricgloroethane with only 9.0%, 3.0%, 5.1% and 2.0% mortalities respectively.Conclusions: Neem, chinaberry and Bti showed potent larvicidal and pupicidal activities. However, in the area, high level of mosquito resistance to pyrethroids and dichlorodiphenyl-tricgloroethane was seen which will pose serious challenge to vector control in the future. Therefore, using integrated approach including these botanical larvicides is warranted to manage insecticide resistance.
Oral delivery mediated RNA interference of a carboxylesterase gene results in reduced resistance to organophosphorus insecticides in the cotton Aphid, Aphis gossypii Glover.
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You-Hui Gong
Full Text Available BACKGROUND: RNA interference (RNAi is an effective tool to examine the function of individual genes. Carboxylesterases (CarE, EC 184.108.40.206 are known to play significant roles in the metabolism of xenobiotic compounds in many insect species. Previous studies in our laboratory found that CarE expression was up-regulated in Aphis gossypii (Glover (Hemiptera: Aphididae adults of both omethoate and malathion resistant strains, indicating the potential involvement of CarE in organophosphorus (OP insecticide resistance. Functional analysis (RNAi is therefore warranted to investigate the role of CarE in A. gossypii to OPs resistance. RESULT: CarE expression in omethoate resistant individuals of Aphis gossypii was dramatically suppressed following ingestion of dsRNA-CarE. The highest knockdown efficiency (33% was observed at 72 h after feeding when dsRNA-CarE concentration was 100 ng/µL. The CarE activities from the CarE knockdown aphids were consistent with the correspondingly significant reduction in CarE expression. The CarE activity in the individuals of control aphids was concentrated in the range of 650-900 mOD/per/min, while in the individuals of dsRNA-CarE-fed aphids, the CarE activity was concentrated in the range of 500-800 mOD/per/min. In vitro inhibition experiments also demonstrated that total CarE activity in the CarE knockdown aphids decreased significantly as compared to control aphids. Bioassay results of aphids fed dsRNA-CarE indicated that suppression of CarE expression increased susceptibility to omethoate in individuals of the resistant aphid strains. CONCLUSION: The results of this study not only suggest that ingestion of dsRNA through artificial diet could be exploited for functional genomic studies in cotton aphids, but also indicate that CarE can be considered as a major target of organophosphorus insecticide (OPs resistance in A. gossypii. Further, our results suggest that the CarE would be a propitious target for OPs resistant
Development of acetylcholinesterase biosensors for neurotoxins detection in foods and the environment
Roepcke, Clarisse Brüning Schmitt
Acetylcholinesterase (AChE) is responsible for the hydrolysis of acetylcholine in the nervous system. It is inhibited by several substances, like organophosphate and carbamate insecticides, glycoalkaloids, nerve gas and anatoxin-a(s). There is a growing need to develop new technologies to reduce time spent with sample preparation, discriminate between positive and negative samples, and to reduce analysis costs. Over the last decades, AChE biosensors have emerged as an ultra sensitive and rapi...
Resistance of Culex tritaeniorhynchus in Huangzhou district,Huanggang city,Hubei province,China to commonly used insecticides and the potential effect of Romanomermis wuchangensis infection on its insecticide resistance%湖北省黄州区三带喙库蚊抗药性调查及武昌罗索线虫感染对其影响研究
Institute of Scientific and Technical Information of China (English)
董循; 潘海; 雷桂兰; 吴中华; 崔峰; 乔传令
目的 了解湖北省黄冈市黄州区近郊三带喙库蚊对常用化学杀虫剂的抗性现状,研究武昌罗索线虫的寄生对其抗性的影响,为蚊虫治理和疾病预防提供技术支撑.方法 采用生物测定法测定湖北省黄州区一中(QYZ)感染了武昌罗索线虫的三带喙库蚊种群和东方广场(DFGC)未感染的三带喙库蚊种群对常用杀虫剂半数致死浓度(LC50),以判定抗性等级.结果 DFGC种群对对硫磷、毒死蜱、敌敌畏、残杀威、巴沙、氯菊酯、高效氯氰菊酯、溴氰菊酯和胺菊酯9种杀虫剂的LC50分别为1.854 74、0.295 74、24.865 10、2.179 81、6.137 24、0.040 87、0.016 69、0.009 60和2.071 32 mg/L;DFGC种群的LC50均高于QYZ种群,比率为1~7倍.与敏感品系相比,黄州区三带喙库蚊对敌敌畏、残杀威、氯菊酯、高效氯氰菊酯和溴氰菊酯的抗性比率分别为388、9、11、8和24倍.结论 黄州区近郊三带喙库蚊对常用化学杀虫剂抗性较高,而武昌罗索线虫的寄生可能是显著降低其对杀虫剂抵抗性的原因.%Objective To investigate the resistance of Culex tritaeniorhynchus in the suburbs of Huangzhou district, Huanggang city, Hubei province, China to commonly used insecticides and the effect of Romanomermis wuchangensis infection on its insecticide resistance, and to provide technical support for mosquito control and disease prevention. Methods The LC50 values of commonly used insecticides for Cx. Tritaeniorhynchus infected with R. Wuchangensis from the First Middle School of Huangzhou (QYZ) and the uninfected Cx. Tritaeniorhynchus from the Dongfang Square (DFGC) were measured by bioassay to evaluate their insecticide resistance levels. Results The LC50 values of parathion, chlorpyrifos, dichlorvos, propoxur, fenobucarb, permethrin, beta-cypermethrin, deltamethrin, and tetramethrin for the uninfected Cx. Tritaeniorhynchus in DFGC were 1.854 74, 0.295 74, 24.865 10, 2.179 81, 6.137 24, 0.040 87, 0.016 69
Combining indoor residual spraying with chlorfenapyr and long-lasting insecticidal bed nets for improved control of pyrethroid-resistant Anopheles gambiae: an experimental hut trial in Benin
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Ngufor Corine
Full Text Available Abstract Background Neither indoor residual spraying (IRS nor long-lasting insecticidal nets (LLINs are able to fully interrupt transmission in holoendemic Africa as single interventions. The combining of IRS and LLINs presents an opportunity for improved control and management of pyrethroid resistance through the simultaneous presentation of unrelated insecticides. Method Chlorfenapyr IRS and a pyrethroid-impregnated polyester LLIN (WHO approved were tested separately and together in experimental huts in southern Benin against pyrethroid resistant Anopheles gambiae and Culex quinquefasciatus. The bed nets were deliberately holed with either six or 80 holes to examine the effect of increasing wear and tear on protectiveness. Anopheles gambiae were genotyped for the kdr gene to assess the combination's potential to prevent the selection of pyrethroid resistance. Results The frequency of kdr was 84%. The overall mortality rates of An. gambiae were 37% and 49% with the six-hole and 80-hole LLINs, respectively, and reached 57% with chlorfenapyr IRS. Overall mortality rates were significantly higher with the combination treatments (82-83% than with the LLIN or IRS individual treatments. Blood feeding (mosquito biting rates were lowest with the 6-hole LLIN (12%, intermediate with the 80-hole LLIN (32% and highest with untreated nets (56% with the 6-hole and 54% with the 80-hole nets. Blood feeding (biting rates and repellency of mosquitoes with the combination of LLIN and chlorfenapyr IRS showed significant improvement compared to the IRS treatment but did not differ from the LLIN treatments indicating that the LLINs were the primary agents of personal protection. The combination killed significantly higher proportions of Cx. quinquefasciatus (51%, 41% than the LLIN (15%, 13% or IRS (32% treatments. Conclusion The chlorfenapyr IRS component was largely responsible for controlling pyrethroid-resistant mosquitoes and the LLIN component was largely
2010年长沙市家蝇抗药性测定研究%Study on Resistance of Musca domestica to Insecticides in Changsha
Institute of Scientific and Technical Information of China (English)
彭莱; 李平非; 谭亮
目的 掌握长沙市城区家蝇抗性动态.方法 点滴法.结果 2010年5种杀虫剂LD50分别为溴氰菊酯0.0262 μg/虫、氯氰菊酯0.3189 μg/虫、氯菊酯0.1490 μg/虫、敌敌畏0.2320 μg/虫、高效氯氰菊酯0.1506μg/虫.结论 长沙市家蝇对5种杀虫剂的抗药性相比于2003年呈整体上升趋势,但抗药性增长到一定程度会出现相对平缓的波动状态.%Objective To investigate the resistance of Musca domestka to pesticides in urban areas of Changsha in 2010. Method Dropping method was used in this study. Results The LD50 of five kinds of pesticides was deltamethrin0.0262, cypermethrin0.3189, permethrin0.1490, DDVP0.2320, andcypemnethrin 0.1506, respectively. Conclusions Compared with the year 2003, the resistance of Musca domestka to the five insecticides showed an overall upward trend, but the resistance was in a state of relatively smooth fluctuation when it increased to a certain extent.
Update on resistance status of Anopheles gambiae s.s. to conventional insecticides at a previous WHOPES field site, "Yaokoffikro", 6 years after the political crisis in Côte d'Ivoire
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Koffi Alphonsine A
Full Text Available Abstract Background At Yaokoffikro field site near Bouaké, in central Côte d'Ivoire, a group of experimental huts built in 1996 served over many years for the evaluation of insecticides against highly resistant mosquitoes. Breeding sites of mosquitoes and selection pressure in the area were maintained by local farming practices until a war broke out in September 2002. Six years after the crisis, we conducted bioassays and biochemical analysis to update the resistance status of Anopheles gambiae s.s. populations and detect other potential mechanisms of resistance that might have evolved. Methods An. gambiae s.s. larvae from Yaokoffikro were collected in breeding sites and reared to adults. Resistance status of this population to insecticides was assessed using WHO bioassay test kits for adult mosquitoes with seven insecticides: two pyrethroids, a pseudo-pyrethroid, an organochloride, two carbamates and an organophosphate. Molecular and biochemical assays were carried out to identify the L1014F kdr and ace-1R alleles in individual mosquitoes and to detect potential increase in mixed function oxidases (MFO, non-specific esterases (NSE and glutathione S-transferases (GST activity. Results High pyrethroids, DDT and carbamate resistance was confirmed in An. gambiae s.s. populations from Yaokoffikro. Mortality rates were less than 70% with pyrethroids and etofenprox, 12% with DDT, and less than 22% with the carbamates. Tolerance to fenitrothion was observed, with 95% mortality after 24 h. PCR analysis of samples from the site showed high allelic frequency of the L1014F kdr (0.94 and the ace-1R (0.50 as before the crisis. In addition, increased activity of NSE, GST and to a lesser extent MFO was found relative to the reference strain Kisumu. This was the first report detecting enhanced activity of these enzymes in An. gambiae s.s from Yaokoffikro, which could have serious implications in detoxification of insecticides. Their specific roles in
Kang, Xin-Le; Zhang, Meng; Wang, Kang; Qiao, Xian-Feng; Chen, Mao-Hua
The ATP-binding cassette (ABC) transporters are important transmembrane proteins encoded by a supergene family. The majority of ABC proteins are primary active transporters that bind and hydrolyze ATP to mediate the efflux of a diverse range of substrates across lipid membranes. In this study, we cloned and characterized a putative multidrug resistance associated protein 1 (MRP1) from Rhopalosiphum padi encoded by ABCC1. Structural analysis showed that this protein has structural features typical of the ABC transporter family. Phylogenetic analysis indicated that the amino acid sequence was highly similar that of the corresponding protein from Acyrthosiphon pisum. Real-time quantitative polymerase chain reaction (PCR) analysis showed that ABCC1 was expressed throughout all R. padi developmental stages, with the highest level of expression in the fourth larval instar. We also examined ABCC1 expression in four different tissue types and found that it was most highly expressed in the midgut. Exposing R. padi to imidacloprid and chlorpyrifos increased ABCC1 expression. Furthermore, ABCC1 expression was higher in the imidacloprid-resistant (IR) and chlorpyrifos-resistant (CR) strains than in an insecticide-susceptible strain (SS) of R. padi. Exposing R. padi to verapamil in combination with insecticides significantly increased the toxicity of the insecticides. The respective synergy factor of CR and IR R. padi strain was 1.33 and 1.26, which was lower than that (2.72 and 1.64, respectively) of the SS. Our results clarify the biological function of ABCC1 in R. padi, particularly its role in insecticide resistance, and suggest novel strategies for pest management that use ABC transporter inhibitors to increase the effectiveness of insecticides.
Target-site resistance to pyrethroid insecticides in German populations of the cabbage stem flea beetle, Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae).
Zimmer, Christoph T; Müller, Andreas; Heimbach, Udo; Nauen, Ralf
Cabbage stem flea beetle, Psylliodes chrysocephala L. (Coleoptera: Chrysomelidae) is a major pest of winter oilseed rape in several European countries particularly attacking young emerging plants in autumn. Over the last several decades, pyrethroid insecticides have been foliarly applied to control flea beetle outbreaks. Recent control failures in northern Germany suggested pyrethroid resistance development in cabbage stem flea beetles, which were confirmed by resistance monitoring bioassays using lambda-cyhalothrin in an adult vial test. The purpose of this study was to investigate the presence of polymorphisms in the para-type voltage-gated sodium channel gene of P. chrysocephala known to be involved in knock-down resistance (kdr). By using a degenerate primer approach we PCR amplified part of the para-type sodium channel gene and identified in resistant flea beetles a single nucleotide polymorphism resulting in an L1014F (kdr) mutation within domain IIS6 of the channel protein, known as one of the chief pyrethroid target-site resistance mechanisms in several other pest insects. Twenty populations including four archived museum samples collected between 1945 and 1958 were analyzed using a newly developed pyrosequencing diagnostic assay. The assay revealed a kdr allele frequency of 90-100% in those flea beetle populations expressing high-level cross-resistance in discriminating dose bioassays against different pyrethroids such as lambda-cyhalothrin, tau-fluvalinate, etofenprox and bifenthrin. The presence of target-site resistance to pyrethroids in cabbage stem flea beetle is extremely worrying considering the lack of effective alternative modes of action to control this pest in Germany and other European countries, and is likely to result in major control problems once it expands to other geographies. The striking fact that cabbage stem flea beetle is next to pollen beetle, Meligethes aeneus the second coleopteran pest in European winter oilseed rape resisting
Synthesis and Computational Simulation of New Phosphorilated Sulfoximines with Insecticidal Activity
Licastrode, S. A.; M. E. Bellozas Reinhard
New organophosphorus insecticides of dialkylsulphoximines derived with activity upon acetylcholinesterase were synthesized. The obtained compounds were characterized by NMR and IR, and anticholinesterase activity and toxicity was measured. A simulation through computer was done in order to establish the relationship between structure and activity.
天津市2010年蚊蝇抗药性监测%Surveillance of the resistance of Culex pipiens pallens and Musca domestica to insecticides in Tianjin in 2010
Institute of Scientific and Technical Information of China (English)
吴彤宇; 张咏梅; 张静; 秦娜; 王伟; 李培羽; 李今越; 郝连义
目的 了解天津市蚊、蝇对常用杀虫剂的抗药性,为科学合理使用杀虫剂提供依据.方法 选择6个区(县)作为监测点,分别用浸渍法和点滴法测定淡色库蚊和家蝇的抗药性.结果 天津市蚊、蝇对常用杀虫剂均产生了一定的抗性,淡色库蚊对DDVP、溴氰菊酯、高效氯氰菊酯、双硫磷和仲丁威的平均相对抗性分别为61.49、13.08、3.72、5.03和17.84倍;家蝇对DDVP、高效氯氰菊酯、溴氰菊酯、残杀威、氯菊酯的平均抗性分别为9.49、58.44、11.24、2.66和2.95倍.结论 各地应根据抗药性监测结果,合理应用杀虫剂,积极提倡综合防制,有效开展灭蚊、蝇工作.%Objective To study the resistance of Culex pipiens pollens and Musca domestica to insecticides in Tianjin in order to provide the basis for better use of insecticides. Methods Six districts(counties) of Tianjin were selected as the surveillance sites. The resistance of mosquitoes to insecticides was evaluated by dipping method, with the topical application method used for the detection of the resistance of houseflies. Results It was found that Cx. Pipiens pattens and M. Domestica in Tianjin were resistant to insecticides to a certain extent. The mean relative resistance of Cx. Pipiens pallens to DDVP, deltaMethri, (3 -Cypermethrin, parathion and fenobucarb were 61.49, 13.08, 3.72, 5.03 and 17.84, respectively, and that of M. Domestica to DDVP, (3-Cypermethrin, deltamethri, propoxur and permethin were 9.49, 58.44, 11.24, 2.66 and 2.95, respectively. Conclusion The resistance of Cx. Pipiens pallens and M. Domestica to different insecticides varies and the surveillance results should be a guidance for the reasonable use of the insecticides for better control of the insects.
昆虫对拟除虫菊酯类杀虫剂的代谢抗性机制研究进展%Mechanism of insect metabolic resistance to pyrethroid insecticides
Institute of Scientific and Technical Information of China (English)
陈澄宇; 史雪岩; 髙希武
随着拟除虫菊酯类杀虫剂在卫生和农业害虫防治中的广泛应用,昆虫对此类杀虫剂产生抗性的报道越来越多。目前已明确昆虫对拟除虫菊酯类杀虫剂的抗性机制包括表皮穿透率下降、靶标抗性以及代谢抗性,其中代谢抗性机制较为普遍,而且其与昆虫对多种杀虫剂的交互抗性关系密切。目前,随着基因组、转录组以及蛋白质组学等新技术的发展及应用,昆虫对拟除虫菊酯类杀虫剂的代谢抗性机制研究也取得了很多新进展。昆虫体内细胞色素 P450酶(P450s)、羧酸酯酶(CarE)及谷胱甘肽S-转移酶(GSTs)等重要解毒酶系的改变均与昆虫对拟除虫菊酯类杀虫剂的代谢抗性有关,其中这3类解毒酶的活性及相关基因表达量的变化是昆虫对此类杀虫剂产生代谢抗性的主要原因。明确昆虫对拟除虫菊酯类杀虫剂的代谢抗性机制,对合理使用此类杀虫剂及延缓抗药性的产生均具有重要意义。本文在总结拟除虫菊酯类杀虫剂代谢路径及相关生物酶研究概况的基础上,综述了近年来有关昆虫对此类杀虫剂代谢抗性机制研究的主要进展。%With indiscriminate use of pyrethroid insecticides on agricultural and urban settings insect pests, the pyrethroid resistance in insects has occurred widely. The resistance mechanisms of insects to pyrethroid insecticides include the resistance caused by the decline of insect cuticular penetration rate, insensitive target resistance and metabolic resistance. Among those mechanisms, the metabolic resistance of insects to pyrethroids is more commonly existed and closely related to insects cross resistance to a variety of insecticides. Recently, many new achievements on the mechanisms of insect metabolic resistance to pyrethroids insecticides have been obtained, with the application of new techniques such as proteomics, transcriptome and genomic techniques. The changes of
Effects of piperonyl butoxide on the toxicity of the organophosphate temephos and the role of esterases in the insecticide resistance of Aedes aegypti
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Boscolli Barbosa Pereira
Full Text Available Introduction The effects of piperonyl butoxide (PBO on the toxicity of the organophosphate temephos (TE and the role of esterases in the resistance of Aedes aegypti to this insecticide were evaluated. Methods A. aegypti L4 larvae susceptible and resistant to TE were pre-treated with PBO solutions in acetone at concentrations of 0.125, 0.25, 0.5, 1, and 2% for 24h and subsequently exposed to a diagnostic concentration of 0.02mg/L aqueous TE solution. The esterase activity of the larvae extracts pre-treated with varying PBO concentrations and exposed to TE for three time periods was determined. Results At concentrations of 0.25, 0.5, 1, and 2%, PBO showed a significant synergistic effect with TE toxicity. High levels of esterase activity were associated with the survival of A. aegypti L4 larvae exposed to TE only. Conclusions The results of the biochemical assays suggest that PBO has a significant inhibitory effect on the total esterase activity in A. aegypti larvae.
Comparative Effectiveness of Insecticides for Use Against the House Fly (Diptera: Muscidae): Determination of Resistance Levels on a Malaysian Poultry Farm.
Ong, Song-Quan; Ahmad, Hamdan; Jaal, Zairi; Rus, Adanan Che
In this study, the toxicology of two commercial larvicides--cyromazine (Neporex 50SP) and ChCy (combination of chlorpyrifos and cypermethrin, Naga 505)--and five commercial adulticides--thiamethoxam (Agita 10WG), cyfluthrin (Responsar WP), lambda-cyhalothrin (Icon 2.8EC), fipronil (Regent 50SC), and imidacloprid (Toxilat 10WP)--was examined against the WHO/VCRU (World Health Organization/ Vector Control Research Unit) susceptible strain and the AYTW (Ayer Tawar) field strain of house fly, Musca domestica L. These pesticides were administered topically, in the diet, or as a dry residue treatment on plywood. Probit analysis using at least five concentrations and the concentration that was lethal to 50% (LC(50)) of the organisms was applied to compare the toxicology and resistance levels of the AYTW population to different insecticides. In the larvicide laboratory study, ChCy was more effective than cyromazine, with a significantly lower LC(50) value when administered topically or in the diet, although the AYTW population was susceptible to both larvicides with a resistance ratio (RR) activity, which significantly reduced adult fly numbers compared with the control group. Cyfluthrin and fipronil were also confirmed to be effective, with a significant reduction in adult fly numbers compared with the control group.
High level of pyrethroid resistance in an Anopheles funestus population of the Chokwe District in Mozambique.
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Nelson Cuamba
Full Text Available BACKGROUND: Although Anopheles funestus is difficult to rear, it is crucial to analyse field populations of this malaria vector in order to successfully characterise mechanisms of insecticide resistance observed in this species in Africa. In this study we carried out a large-scale field collection and rearing of An. funestus from Mozambique in order to analyse its susceptibility status to insecticides and to broadly characterise the main resistance mechanisms involved in natural populations. METHODOLOGY/PRINCIPAL FINDINGS: 3,000 F(1 adults were obtained through larval rearing. WHO susceptibility assays indicated a very high resistance to pyrethroids with no mortality recorded after 1 h 30 min exposure and less than 50% mortality at 3 h 30 min. Resistance to the carbamate, bendiocarb was also noted, with 70% mortality after 1h exposure. In contrast, no DDT resistance was observed, indicating that no kdr-type resistance was involved. The sequencing of the acetylcholinesterase gene indicated the absence of the G119S and F455W mutations associated with carbamate and organophosphate resistance. This could explain the absence of malathion resistance in this population. Both biochemical assays and quantitative PCR implicated up-regulated P450 genes in pyrethroid resistance, with GSTs playing a secondary role. The carbamate resistance observed in this population is probably conferred by the observed altered AChE with esterases also involved. CONCLUSION/SIGNIFICANCE: The high level of pyrethroid resistance in this population despite the cessation of pyrethroid use for IRS in 1999 is a serious concern for resistance management strategies such as rotational use of insecticides. As DDT has now been re-introduced for IRS, susceptibility to DDT needs to be closely monitored to prevent the appearance and spread of resistance to this insecticide.
Resistance of Blattella germanica to four kinds of common used insecticides in Shanghai%上海市德国小蠊对4种常用杀虫剂的抗药性测定
Institute of Scientific and Technical Information of China (English)
刘洪霞; 徐仁权; 冷培恩; 张春哲
Objective To know the resistance of Blattella germanica to four kinds of common used insecticides in Shanghai. Methods The surface contact method was used. Results The field population of B. Germanica had different resistance to deltamethrin, cypermethrin, propoxur and dichlorovos. The resistance ratios to these tested insecticides were 3.39 - 16.87, 1.41 - 13.61, 0.57-4.39 and 4.44-4.89 respectively. Of which, the resistance of CN population to deltamethrin and cypermethrin was higher. Conclusion The resistance of B. Germanica field population to four kinds of insecticides differs greatly, so the cockroach control by chemical method must be selected suitable insecticides.%目的 全面了解上海市德国小蠊对4种常用杀虫药剂的抗药性,指导科学、合理使用杀虫剂.方法药膜接触法.结果德国小蠊野外种群对溴氰菊酯、氯氰菊酯、残杀威和敌敌畏均产生了不同程度的抗药性,其抗性系数分别为3.39~16.87、1.41 ~ 13.61、0.57~4.39和4.44~4.89,其中CN种群对溴氰菊酯和氯氰菊酯的抗性较高.结论上海地区德国小蠊不同种群对4种杀虫剂的敏感度有很大差异,进行化学防治时必须选择合适的杀虫剂.
The Stability of Resistance and the Strategies for Management of Insecticide Resistance in Plutella xylostella(L.)%小菜蛾抗性稳定性及抗性治理对策研究
Institute of Scientific and Technical Information of China (English)
吴刚; 尤民生; 赵士熙
试验表明,福州地区田间小菜蛾已对有机磷、氨基甲酸酯及拟除虫菊酯产生高抗性。脱离选择压力3代后,小菜蛾的抗性水平迅速下降。Bt预处理可提高抗性和敏感小菜蛾幼虫对有机磷的敏感性,尤其对抗性小菜蛾增效极显著,对敏感小菜蛾AChE的Ki值则影响不大。据此提出在抗性治理中,应轮用或换用不同毒理机制的杀虫剂,且其间隔至少为2~3代。%High resistances to organophosphates(OPs), carbamates and pyrethroids were found in the field strain of diamondback moth(DBM),P. xylostella(L.),in Fuzhou,Fujian Province. The resistance quickly decreased after DBM were released from selection pressure for only 3 generations,and significant synergism to OPs in R strain was found after 24 h pretreatment with Bt. The activities of AchE were strongly depressed by Bt pretreatment in R Strain. The higher values of Ki were detected in R Strain with Bt pretreatment, but no significant changes in S strain. The results showed that the resistance management of insecticides with different toxicity mechanism, in volving alternating and mixing insecticide, should be adopted in IPM strategies.
Carbamate and Pyrethroid Resistance in the Akron Strain of Anopheles gambiae
Mutunga, James M.; Anderson, Troy D.; Craft, Derek T.; Gross, Aaron D.; Swale, Daniel R.; Tong, Fan; Wong, Dawn M.; Carlier, Paul R.; Bloomquist, Jeffrey R.
Insecticide resistance in the malaria vector, Anopheles gambiae is a serious problem, epitomized by the multi-resistant Akron strain, originally isolated in the country of Benin. Here we report resistance in this strain to pyrethroids and DDT (13-fold to 35-fold compared to the susceptible G3 strain), but surprisingly little resistance to etofenprox, a compound sometimes described as a "pseudo-pyrethroid." There was also strong resistance to topically-applied commercial carbamates (45-fold to 81-fold), except for the oximes aldicarb and methomyl. Biochemical assays showed enhanced cytochrome P450 monooxygenase and carboxylesterase activity, but not that of glutathione-S-transferase. A series of substituted α,α,α,-trifluoroacetophenone oxime methylcarbamates were evaluated for enzyme inhibition potency and toxicity against G3 and Akron mosquitoes. The compound bearing an unsubstituted phenyl ring showed the greatest toxicity to mosquitoes of both strains. Low cross resistance in Akron was retained by all analogs in the series. Kinetic analysis of acetylcholinesterase activity and its inhibition by insecticides in the G3 strain showed inactivation rate constants greater than that of propoxur, and against Akron enzyme inactivation rate constants similar to that of aldicarb. However, inactivation rate constants against recombinant human AChE were essentially identical to that of the G3 strain. Thus, the acetophenone oxime carbamates described here, though potent insecticides that control resistant Akron mosquitoes, require further structural modification to attain acceptable selectivity and human safety. PMID:26047119
Resistance of Brazilian diamondback moth populations to insecticides Resistência de populações brasileiras de traça das brássicas a inseticidas
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Alexandre Conte de Oliveira
Full Text Available Plutella xylostella is a recurring pest on cruciferous crops around the world. In Brazil, it typically requires large number of insecticide sprays, which may lead to fast evolution of resistance. The aim of this study was to assess the susceptibility of Brazilian diamondback moth populations to the insecticides abamectin, deltamethrin, and spinosad. Leaf dip bioassays were used to determine mortality data obtained after 48 h of exposure to insecticides and subjected to Probit analysis. The population from Bonito, state of Pernambuco, Brazil, had the highest toxicity ratio (20.2 - fold to abamectin compared to the reference population. The LC50 values for deltamethrin ranged from 85.2 to 360.1 mg L-1, demonstrating a high survival of populations in relation to this insecticide field dose rate (7.5 mg L-1. The toxicity ratios of the estimated LC50s, however, were very low (varying from 2.2 - to 4.2 - fold. Most populations exhibited toxicity ratios for spinosad, ranging from 2.3 - to 5.1 - fold, while both the LC50 and LC95 values reflected a high susceptibility to the spinosad field dosage (120 mg L-1. Only the Bonito - PE population resisted to abamectin, while all P. xylostella populations were resistant to deltamethrin, but particularly susceptible to spinosad because of the absence of selection pressure with it in these areas.Plutella xylostella é uma praga recorrente em brássicas de todo o mundo. No Brasil, normalmente exige grande número de pulverizações de inseticidas, que pode levar à rápida evolução da resistência. Avaliou-se a suscetibilidade de populações brasileiras da traça das crucíferas aos inseticidas abamectina, deltametrina e espinosade. Bioensaios de imersão de folhas foram utilizados para determinar a mortalidade, sendo os dados obtidos após 48 h de exposição aos inseticidas e submetidos à análise de Probit. A população de Bonito-PE apresentou a maior razão de toxicidade (20,2 vezes para abamectina em
Insecticide-induced hormesis and arthropod pest management.
Guedes, Raul Narciso C; Cutler, G Christopher
Ecological backlashes such as insecticide resistance, resurgence and secondary pest outbreaks are frequent problems associated with insecticide use against arthropod pest species. The last two have been particularly important in sparking interest in the phenomenon of insecticide-induced hormesis within entomology and acarology. Hormesis describes a biphasic dose-response relationship that is characterized by a reversal of response between low and high doses of a stressor (e.g. insecticides). Although the concept of insecticide-induced hormesis often does not receive sufficient attention, or has been subject to semantic confusion, it has been reported in many arthropod pest species and natural enemies, and has been linked to pest outbreaks and potential problems with insecticide resistance. The study of hormesis remains largely neglected in entomology and acarology. Here, we examined the concept of insecticide-induced hormesis in arthropods, its functional basis and potential fitness consequences, and its importance in arthropod pest management and other areas.
宝鸡市家蝇对常用杀虫剂抗性状况及防治对策%Resistance of Musca domestica to insecticides and countermeasure for its control in Baoji city
Institute of Scientific and Technical Information of China (English)
张铮; 吕文; 李旭龙; 张宝芳; 王军浩
Objective To find out the situation of Musca domestica' s resistance to insecticides in Baoji city, and provide scientific use of insecticides in Baoji. Methods Dropping method was adopted to determine median lethal dose of Musca domestica. Results LD50 of the eight insecticides of Musca domestica in Baoji city was 0.016 - 22.092 μg per piece. The resistance ratios of Musca domestica to DDVP, deltamethrin, propoxur, cypermethrin were 38. 21,36. 51,103. 41 and 7. 82 respectively. Conclusion In Baoji city,Musca domestica have had resistance to DDVP,deltamethrin, propoxur, cypermethrin in different degrees, so it is necessary to reinforce scientific and effective drug regimen to prevent and delay the rising of Musca domestica's resistance to insecticides.%目的 了解宝鸡市家蝇抗药性情况,以便科学合理地使用杀虫剂.方法 采用点滴法,测定家蝇半数致死量.结果 宝鸡市家蝇对8种杀虫剂的LD50为0.016 ~ 22.092μg/只.敌敌畏、溴氰菊酯、残杀威、高效氯氰菊酯的抗药倍数分别为38.21、36.51、103.41、7.82.结论 宝鸡市家蝇对敌敌畏、溴氰菊酯、残杀威、高效氯氰菊酯均已产生了不同程度的抗药性,今后应加强科学合理用药,预防和延缓家蝇抗药性的增长.
Insecticide resistance status of woolly apple aphid, Eriosoma lanigerum in China%苹果绵蚜田间种群的抗性监测
Institute of Scientific and Technical Information of China (English)
祝菁; 李晨歌; 沈雅楠; 张濛; 陈金华; 朱佳伟; 李烨; 姜卫华
To evaluate the current situation and development of resistance of woolly apple aphid, Eriosoma lanigerum (Hausmann), to conventional insecticides in China, the sensitivity of theE. lanigerum populations from several apple orchards of Qapqal in Xinjiang, Jinan in Shandong province, Qian county in Shaanxi province, Changli in Hebei province and Feng county in Jiangsu province to chlorpyrifos,lambda-cyhalothrin and imidacloprid were investigated by using the leaf dipping method during 2012–2015. Meanwhile, the enzyme activity of esterase and glutathioneS-transferase of the populations were determined. The Qapqal population in 2012 was the most susceptible sample and it was selected as a reference strain. Compared with Qapqal 2012, all the other populations developed different levels of resistance to imidacloprid with the highest level found in Qapqal and Feng populations in 2015 (resistance ratio, RR > 2 000 fold). As tolambda-cyhalothrin, the aphid populations found in Qian, Changli and Qapqal at 2014 were susceptible, while the populations from Jinan during different years, Feng and Qapaqal at 2015 developed medium to high levels of resistance. With regard to chlorpyrifos, Qian population exhibited susceptibility, while Qapaqal, Jinan, Changli and Feng populations exhibited low to high levels of resistance. The investigation of the detoxification enzyme activity indicated that there was significant correlation between resistance levels of imidacloprid and lambda-cyhalothrin and the activity of glutathioneS-transferase, respectively. However, the similar correlation was not observed with esterase. The results demonstrated that most of the tested populations ofE. lanigerum developed different levels of resistance to three tested insecticides, showing a tendency to increase yearly; the resistance level to imidacloprid was the highest; and reasonable rotation of insecticides should be used in the control ofE. lanigerum.%为了掌握果�
Microdistribution of the resistance of malaria vectors to deltamethrin in the region of Plateau (southeastern Benin) in preparation for an assessment of the impact of resistance on the effectiveness of Long Lasting Insecticidal Nets (LLINs)
Background This study aims to research two areas, one with a resistant and the other with a susceptible profile of An. gambiae to deltamethrin in the region of Plateau (southern Benin). In each area, eight localities were sought. Both areas were needed for the assessment of the impact of malaria vector resistance to pyrethroids on the effectiveness of Long Lasting Insecticidal Nets (LLINs). The susceptible area of An. gambiae to deltamethrin was used as a control. Methods In total, 119 localities in the region of Plateau were screened by sampling An. gambiae s.l larvae. Female mosquitoes resulting from these larvae were exposed to 0.05% deltamethrin following WHO standards. PCR was used to identify species and molecular forms of the dead and alive mosquitoes. Finally, we identified kdr mutations (1014 F and1014S) using the HOLA technique. Results Fifty-six out of 119 prospected localities tested positive for Anopheles gambae s.l breeding sites. The results showed that An. gambiae was resistant to deltamethrin in 39 localities and susceptible in only 2 localities; resistance to deltamethrin was suspected in 15 localities. The HOLA technique confirmed the presence of kdr 1014 F mutation and the absence of kdr 1014S mutation. The kdr 1014 F mutation was found in both M and S molecular forms at relatively high frequencies therefore confirming the susceptibility tests. Conclusion We were unable to identify the eight susceptible areas due to the overall resistance of An. gambiae to deltamethrin in the region of Plateau. To implement the study, we kept two areas, one with high resistance (R+++) and the other with low resistance (R+) of An. gambiae to deltamethrin. PMID:24564260
Investigation on resistance to common insecticides of blattella germanica in Lianyungang City%连云港市德国小蠊对常用杀虫剂的抗药性调查
Institute of Scientific and Technical Information of China (English)
魏春清; 周日辉; 赵兴
目的 研究并掌握连云港市德国小蠊对常用杀虫剂的抗性情况,为合理使用杀虫剂提供科学依据.方法 采用常用的药膜接触法,测定德国小蠊对高效氯氰菊酯、乙酰甲胺磷和残杀威抗药性.结果 连云港市德国小蠊对高效氯氰菊酯、乙酰甲胺磷和残杀威的抗性系数分别为38.2、6.0和1.8,其抗性水平分别为高度抗性、中度抗性和低度抗性.结论 连云港市德国小蠊对高效氯氰菊酯、乙酰甲胺磷抗和残杀威均产生不同程度的抗性,在防制蟑螂中,应根据抗性情况合理选择杀虫剂,以提高蟑螂的防制效果.%Objective To study and understand the resistance to common insecticides of blattella germanica in Lianyungang, and provide scientific basis for rational use of insecticides. Method Use the common drug contacting method of drug sensitive layers to determiner the resistance to cypermethrin, acephate and propoxur of blattella germanica. Results The resistance coefficients of blattella germanica to cypermethrin, acephate and propoxur were 38. 2, 6. 0, 1. 8, and the resistance levels were high, moderate and low resistance, respectively. Conclusions Blattella germanica had different resistance to cypermethrin, acephate and propoxur. We should select appropriate insecticides to improve the control effect of cockroach according to their resistance to drugs.
Relationship of structure to effectiveness of some organophosphorus insecticides and the crystal and molecular structures of tris(bicarbonato) tetraaquoholmium (III) dihydrate and tris(ethylenediamine-cobalt (III) tetrakis (isothiocyanato cobaltate(II) nitrate
Energy Technology Data Exchange (ETDEWEB)
Rohrbaugh, W. J.
Results are reported from an investigation of correlations between molecular structural parameters of selected organophosphorus insecticides and their corresponding toxic effectiveness. The crystal and molecular structures of azinphos-methyl, emidithion, and tetrachlorvinphos were determined via three-dimensional x-ray analysis. Acetylcholinesterase (AChE) in nerve cells was identified as the target for organophosphorus insecticides.
Possibility of Acetylcholinesterase Overexpression in Alzheimer Disease Patients after Therapy with Acetylcholinesterase Inhibitors
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Alžběta Kračmarová
Full Text Available Acetylcholinesterase is an enzyme responsible for termination of excitatory transmission at cholinergic synapses by the hydrolyzing of a neurotransmitter acetylcholine. Nowadays, other functions of acetylcholinesterase in the organism are considered, for example its role in regulation of apoptosis. Cholinergic nervous system as well as acetylcholinesterase activity is closely related to pathogenesis of Alzheimer disease. The mostly used therapy of Alzheimer disease is based on enhancing cholinergic function using inhibitors of acetylcholinesterase like rivastigmine, donepezil or galantamine. These drugs can influence not only the acetylcholinesterase activity but also other processes in treated organism. The paper is aimed mainly on possibility of increased expression and protein level of acetylcholinesterase caused by the therapy with acetylcholinesterase inhibitors.
Possibility of Acetylcholinesterase Overexpression in Alzheimer Disease Patients after Therapy with Acetylcholinesterase Inhibitors.
Kračmarová, Alžběta; Drtinová, Lucie; Pohanka, Miroslav
Acetylcholinesterase is an enzyme responsible for termination of excitatory transmission at cholinergic synapses by the hydrolyzing of a neurotransmitter acetylcholine. Nowadays, other functions of acetylcholinesterase in the organism are considered, for example its role in regulation of apoptosis. Cholinergic nervous system as well as acetylcholinesterase activity is closely related to pathogenesis of Alzheimer disease. The mostly used therapy of Alzheimer disease is based on enhancing cholinergic function using inhibitors of acetylcholinesterase like rivastigmine, donepezil or galantamine. These drugs can influence not only the acetylcholinesterase activity but also other processes in treated organism. The paper is aimed mainly on possibility of increased expression and protein level of acetylcholinesterase caused by the therapy with acetylcholinesterase inhibitors.
Selective and irreversible inhibitors of mosquito acetylcholinesterases for controlling malaria and other mosquito-borne diseases.
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Yuan-Ping Pang
Full Text Available New insecticides are urgently needed because resistance to current insecticides allows resurgence of disease-transmitting mosquitoes while concerns for human toxicity from current compounds are growing. We previously reported the finding of a free cysteine (Cys residue at the entrance of the active site of acetylcholinesterase (AChE in some insects but not in mammals, birds, and fish. These insects have two AChE genes (AP and AO, and only AP-AChE carries the Cys residue. Most of these insects are disease vectors such as the African malaria mosquito (Anopheles gambiae sensu stricto or crop pests such as aphids. Recently we reported a Cys-targeting small molecule that irreversibly inhibited all AChE activity extracted from aphids while an identical exposure caused no effect on the human AChE. Full inhibition of AChE in aphids indicates that AP-AChE contributes most of the enzymatic activity and suggests that the Cys residue might serve as a target for developing better aphicides. It is therefore worth investigating whether the Cys-targeting strategy is applicable to mosquitocides. Herein, we report that, under conditions that spare the human AChE, a methanethiosulfonate-containing molecule at 6 microM irreversibly inhibited 95% of the AChE activity extracted from An. gambiae s. str. and >80% of the activity from the yellow fever mosquito (Aedes aegypti L. or the northern house mosquito (Culex pipiens L. that is a vector of St. Louis encephalitis. This type of inhibition is fast ( approximately 30 min and due to conjugation of the inhibitor to the active-site Cys of mosquito AP-AChE, according to our observed reactivation of the methanethiosulfonate-inhibited AChE by 2-mercaptoethanol. We also note that our sulfhydryl agents partially and irreversibly inhibited the human AChE after prolonged exposure (>4 hr. This slow inhibition is due to partial enzyme denaturation by the inhibitor and/or micelles of the inhibitor, according to our studies using
Relationship between Resistance of Rice Stem Borer and Insecticide Use Intensity in South China%中国华南水稻螟虫抗药性与用药的关系
Institute of Scientific and Technical Information of China (English)
周克; 闫苗苗
[Objective] This study aimed to survey the effect of insecticide use intensity on the resistance of rice stem borer in South China.[Method] The data includes 19 counties from Guangdong Province and Guangxi Province from 1991 to 2010.A fixed effect model was established to evaluate the effect of insecticide use intensity on the resistance of rice stem borer.[Result] The regression results suggest that one-period lagged total number of insecticide sprays has significant effect on the infestation level of rice stem borer.[Conclusion] Although rice stem borer is a migratory rice pest,insecticide use intensity has significant effect on the resistance level of rice stem borer in South China.%[目标]研究中国华南稻田用药强度对水稻螟虫的抗药性的影响.[方法]采用来自广东和广西的19个水稻种植县从1991年到2010年的面板数据,建立个体固定效应模型.[结果]滞后一期针对水稻螟虫的总用药次数对当期水稻螟虫的发生级别有显著的正的影响.[结论]虽然水稻螟虫是一种迁飞性害虫,但是不同地区的农民的用药行为都受到了水稻螟虫发生级别的影响,因此,长期来看滞后一期用药对当期水稻螟虫的抗药性有显著的正的影响.
Behavioral and metabolic effects of sublethal doses of two insecticides, chlorpyrifos and methomyl, in the Egyptian cotton leafworm, Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae).
Dewer, Youssef; Pottier, Marie-Anne; Lalouette, Lisa; Maria, Annick; Dacher, Matthieu; Belzunces, Luc P; Kairo, Guillaume; Renault, David; Maibeche, Martine; Siaussat, David
Insecticides have long been used as the main method in limiting agricultural pests, but their widespread use has resulted in environmental pollution, development of resistances, and biodiversity reduction. The effects of insecticides at low residual doses on both the targeted crop pest species and beneficial insects have become a major concern. In particular, these low doses can induce unexpected positive (hormetic) effects on pest insects, such as surges in population growth exceeding what would have been observed without pesticide application. Methomyl and chlorpyrifos are two insecticides commonly used to control the population levels of the cotton leafworm Spodoptera littoralis, a major pest moth. The aim of the present study was to examine the effects of sublethal doses of these two pesticides, known to present a residual activity and persistence in the environment, on the moth physiology. Using a metabolomic approach, we showed that sublethal doses of methomyl and chlorpyrifos have a systemic effect on the treated insects. We also demonstrated a behavioral disruption of S. littoralis larvae exposed to sublethal doses of methomyl, whereas no effects were observed for the same doses of chlorpyrifos. Interestingly, we highlighted that sublethal doses of both pesticides did not induce a change in acetylcholinesterase activity in head of exposed larvae.
Resistance mutation conserved between insects and mites unravels the benzoylurea insecticide mode of action on chitin biosynthesis.
Douris, Vassilis; Steinbach, Denise; Panteleri, Rafaela; Livadaras, Ioannis; Pickett, John Anthony; Van Leeuwen, Thomas; Nauen, Ralf; Vontas, John
Despite the major role of chitin biosynthesis inhibitors such as benzoylureas (BPUs) in the control of pests in agricultural and public health for almost four decades, their molecular mode of action (MoA) has in most cases remained elusive. BPUs interfere with chitin biosynthesis and were thought to interact with sulfonylurea receptors that mediate chitin vesicle transport. Here, we uncover a mutation (I1042M) in the chitin synthase 1 (CHS1) gene of BPU-resistant Plutella xylostella at the same position as the I1017F mutation reported in spider mites that confers etoxazole resistance. Using a genome-editing CRISPR/Cas9 approach coupled with homology-directed repair (HDR) in Drosophila melanogaster, we introduced both substitutions (I1056M/F) in the corresponding fly CHS1 gene (kkv). Homozygous lines bearing either of these mutations were highly resistant to etoxazole and all tested BPUs, as well as buprofezin-an important hemipteran chitin biosynthesis inhibitor. This provides compelling evidence that BPUs, etoxazole, and buprofezin share in fact the same molecular MoA and directly interact with CHS. This finding has immediate effects on resistance management strategies of major agricultural pests but also on mosquito vectors of serious human diseases such as Dengue and Zika, as diflubenzuron, the standard BPU, is one of the few effective larvicides in use. The study elaborates on how genome editing can directly, rapidly, and convincingly elucidate the MoA of bioactive molecules, especially when target sites are complex and hard to reconstitute in vitro.
Multiple origins of pyrethroid insecticide resistance across the species complex of a nontarget aquatic crustacean, Hyalella azteca.
Weston, Donald P; Poynton, Helen C; Wellborn, Gary A; Lydy, Michael J; Blalock, Bonnie J; Sepulveda, Maria S; Colbourne, John K
Use of pesticides can have substantial nonlethal impacts on nontarget species, including driving evolutionary change, often with unknown consequences for species, ecosystems, and society. Hyalella azteca, a species complex of North American freshwater amphipods, is widely used for toxicity testing of water and sediment and has frequently shown toxicity due to pyrethroid pesticides. We demonstrate that 10 populations, 3 from laboratory cultures and 7 from California water bodies, differed by at least 550-fold in sensitivity to pyrethroids. The populations sorted into four phylogenetic groups consistent with species-level divergence. By sequencing the primary pyrethroid target site, the voltage-gated sodium channel, we show that point mutations and their spread in natural populations were responsible for differences in pyrethroid sensitivity. At least one population had both mutant and WT alleles, suggesting ongoing evolution of resistance. Although nonresistant H. azteca were susceptible to the typical neurotoxic effects of pyrethroids, gene expression analysis suggests the mode of action in resistant H. azteca was not neurotoxicity but was oxidative stress sustained only at considerably higher pyrethroid concentrations. The finding that a nontarget aquatic species has acquired resistance to pesticides used only on terrestrial pests is troubling evidence of the impact of chronic pesticide transport from land-based applications into aquatic systems. Our findings have far-reaching implications for continued uncritical use of H. azteca as a principal species for monitoring and environmental policy decisions.
Efficacy of PermaNet® 2.0 and PermaNet® 3.0 against insecticide-resistant Anopheles gambiae in experimental huts in Côte d'Ivoire
Koffi Alphonsine A; Koudou Benjamin G; Malone David; Hemingway Janet
Abstract Background Pyrethroid resistance in vectors could limit the efficacy of long-lasting insecticidal nets (LLINs) because all LLINs are currently treated with pyrethroids. The goal of this study was to evaluate the efficacy and wash resistance of PermaNet® 3.0 compared to PermaNet® 2.0 in an area of high pyrethroid in Côte d'Ivoire. PermaNet® 3.0 is impregnated with deltamethrin at 85 mg/m2 on the sides of the net and with deltamethrin and piperonyl butoxide on the roof. PermaNet® 2.0 i...
Resistance of Blattella germanica to five kinds of insecticides in Shandong Province%山东省德国小蠊对5种杀虫剂的抗药性调查研究
Institute of Scientific and Technical Information of China (English)
王学军; 赖世宏; 赵志刚; 宫学诗; 霍新北
目的 了解山东省德国小蠊对常用杀虫剂的抗药性现状,指导科学、合理选择和使用杀虫剂.方法 药膜接触法.结果 山东省7个地区德国小蠊野外品系对氯氰菊酯、溴氰菊酯、高效氯氰菊酯、乙酰甲胺磷和残杀威的抗性系数分别为3.57 ~ 37.99、2.11 ~28.49、1.83~ 8.42、1.31 ~7.44、0.84~ 1.87.其中济南、淄博、德州和曲阜野外品系对溴氰菊酯抗性水平较高,济南、淄博和东营野外品系对氯氰菊酯抗性水平较高.结论 山东省部分地区德国小蠊对5种常用杀虫剂均产生了不同程度的抗药性,其中对氯氰菊酯和溴氰菊酯的抗性水平最高;对高效氯氰菊酯和乙酰甲胺磷的抗药性处于中、低度水平,对残杀威为低度抗性.%Objective To study the resistance of Blattella germanica to common used insecticides in Shandong Province,and provide evidence for using insecticides scientifically and reasonably. Methods Residual film method. Results The resistance ratios of seven field-collected strains to cypermethrin, deltamethrin, beta-cyper-methrin, acephate and propoxur were 3. 57 - 37. 99, 2. 11 - 28. 49, 1. 83 - 8. 42, 1. 37 - 7. 44 and 0. 84 - 1. 87 respectively. The resistance ratios of deltamethrin were high in Jinan,Zibo, Dezhou and Qufu for field-collected strains. The resistance also reached the high level to cypermethrin in Jinan, Zibo and Dongying for three field-collected strains. Conclusion Currently, different resistance levels to common insecticides have been developed in seven geographic populations of Blattella germanica within Shandong Province. Among the five commonly used insecticides, the resistance levels to cypermethrin and deltamethrin are the highest, followed by beta-cypermethrin and acephate, and the resistance levels to propoxur are low.
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H. Vatandoost
Full Text Available Anopheles culicifacies s.l. plays an important role In transmission of malaria in Sistan and Baluchistan province, southeastern Iran. Adult susceptibility test on fieltt-collccled mosquitoes was conducted in Ohasreghand district. WHO diagnostic test procedures revealed that adult females were resistant to 0.4% dieUirin (mortality 64.5 ± 3.13, tolerant to 0.1% propoxur (mortality 88.5 ± 2.24 and susceptible to 4% DDT (mortality 98.75 ± 0.8. 5% malathion (mortality 100%, 0.1% bendiocarb (mortality 98.86 ± 0.7, 0.25% pcrmcthrin (mortality 98.4 ± 0.1, ami 0.1% lamhdacyhalothrin (mortality 100%. Malathion and lamhdacyhalothrin had the highest efficacy against this species when they were exposed at the diagnostic dose for 1 hour followed by a 24 hour recovery period. DieUirin, DDT a nil malathion had been used for malaria control as an indoor residual spraying. Tlic implication of these findings in the control programme is discussed.
Acetylcholinesterase Immobilized on Magnetic Beads for Pesticides Detection: Application to Olive Oil Analysis
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Ihya Ait-Ichou
Full Text Available This work presents the development of bioassays and biosensors for the detection of insecticides widely used in the treatment of olive trees. The systems are based on the covalent immobilisation of acetylcholinesterase on magnetic microbeads using either colorimetry or amperometry as detection technique. The magnetic beads were immobilised on screen-printed electrodes or microtitration plates and tested using standard solutions and real samples. The developed devices showed good analytical performances with limits of detection much lower than the maximum residue limit tolerated by international regulations, as well as a good reproducibility and stability.
经敌敌畏选育家蝇对常用杀虫剂交互抗性的研究%Cross resistance of dichlorvos selected Musca domestica to commonly used insecticides
Institute of Scientific and Technical Information of China (English)
李彦; 孙宏迪; 史慧勤; 杨振洲
目的 探讨经敌敌畏选育家蝇对常用杀虫剂的交互抗性,为合理使用杀虫剂提供依据.方法 采用微量点滴法.结果 敌敌畏、乙酰甲胺磷、残杀威、高效氯氰菊酯对家蝇的抗性系数分别为19.61、6.81、9.81、9.86.结论 当家蝇对敌敌畏杀虫剂产生抗性以后,对乙酰甲胺磷、残杀威和高效氯氰菊酯均产生了交互抗性.%Objective To study the cross resistance of dichlorvos selected Musca domestica to commonly used insecticides and supply evidence for using insecticides reasonably.Methods Topical application method.Results The Musca domestica resistant ratios to dichlorvos,acephate,propoxur,beta-cypermethrin respectively were 19.61,6.81,9.81 and 9.86 respectively.Conclusion After the Musca domestica has resistance to dichlorvos,acephate,they have cross resistance to propoxur and beta-cypermethrin.
Resistência a inseticidas em populações de Simulium (Diptera, Simuliidae Insecticide resistance in Simulium populations (Diptera, Simuliidae
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Jairo Campos
Full Text Available Populações de Simulium (Chirostilbia pertinax Kollar, 1832 do Sul e Sudeste do Brasil, foram analisadas quanto à susceptibilidade ao Temephos, considerando-se os históricos de controle e possível resistência. Bioensaios in situ foram realizados para populações dos estados do Paraná (Tibaji e Rolândia, Rio de Janeiro (Muriqui e São Paulo (Barra do Una, Ilhabela, e Morungaba. As populações foram caracterizadas como susceptíveis (S ou resistentes (R submetendo-se larvas nos últimos estádios a uma concentração operacional (0,1ppm i.a./10min de Temephos (Abate 500E como diagnóstica. Os possíveis mecanismos para o desenvolvimento de resistência ao organofosforado são discutidos considerando-se antigas e novas estratégias de controle.Populations of Simulium (Chirostilbia pertinax Kollar, 1832 from Southern and Southeastern States of Brazil were analyzed for temephos susceptibility considering control historical information and possible resistance. In situ bioassays were carried out for populations from the states of Paraná (Tibaji and Rolândia, Rio de Janeiro (Muriqui and São Paulo (Barra do Una, Ilhabela and Morungaba. The populations were characterized as susceptible (S or resistant (R by submitting larvae in the last instars to an operational concentration (0.1ppm a.i./10min of temephos (Abate 500E as diagnostic. The possible mechanisms for the organophosphorus resistance development are discussed considering old and new control strategies.
Altered GPI modification of insect AChE improves tolerance to organophosphate insecticides.
Kakani, Evdoxia G; Bon, Suzanne; Massoulié, Jean; Mathiopoulos, Kostas D
The olive fruit fly Bactrocera oleae is the most destructive and intractable pest of olives. The management of B. oleae has been based on the use of organophosphate (OP) insecticides, a practice that induced resistance. OP-resistance in the olive fly was previously shown to be associated with two mutations in the acetylcholinesterase (AChE) enzyme that, apparently, hinder the entrance of the OP into the active site. The search for additional mutations in the ace gene that encodes AChE revealed a short deletion of three glutamines (Δ3Q) from a stretch of five glutamines, in the C-terminal peptide that is normally cleaved and substituted by a GPI anchor. We verified that AChEs from B. oleae and other Dipterans are actually GPI-anchored, although this is not predicted by the "big-PI" algorithm. The Δ3Q mutation shortens the unusually long hydrophilic spacer that follows the predicted GPI attachment site and may thus improve the efficiency of GPI anchor addition. We expressed the wild type B. oleae AChE, the natural mutant Δ3Q and a constructed mutant lacking all 5 consecutive glutamines (Δ5Q) in COS cells and compared their kinetic properties. All constructs presented identical K(m) and k(cat) values, in agreement with the fact that the mutations did not affect the catalytic domain of the enzyme. In contrast, the mutants produced higher AChE activity, suggesting that a higher proportion of the precursor protein becomes GPI-anchored. An increase in the number of GPI-anchored molecules in the synaptic cleft may reduce the sensitivity to insecticides.
Musical hallucinations treated with acetylcholinesterase inhibitors
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Jan Dirk eBlom
Full Text Available Musical hallucinations are relatively rare auditory percepts which, due to their intrusive nature and the accompanying fear of impending mental decline, tend to cause significant distress and impairment. Although their etiology and pathophysiology appear to be heterogeneous and no evidence-based treatment methods are available, case reports indicate that acetylcholinesterase inhibitors may yield positive results in patients with comorbid hearing loss. We present two female patients (aged 76 and 78 years both of whom suffered from hearing impairment and practically incessant musical hallucinations. Both patients were successfully treated with the acetylcholinesterase inhibitor rivastigmine. Based on these two case descriptions and an overview of studies describing the use of acetylcholinesterase inhibitors in similar patients, we discuss possible mechanisms and propose further research on the use of acetylcholinesterase inhibitors for musical hallucinations experienced in concordance with hearing loss.
Musical hallucinations treated with acetylcholinesterase inhibitors.
Blom, Jan Dirk; Coebergh, Jan Adriaan F; Lauw, René; Sommer, Iris E C
Musical hallucinations are relatively rare auditory percepts which, due to their intrusive nature and the accompanying fear of impending mental decline, tend to cause significant distress and impairment. Although their etiology and pathophysiology appear to be heterogeneous and no evidence-based treatment methods are available, case reports indicate that acetylcholinesterase inhibitors may yield positive results in patients with comorbid hearing loss. We present two female patients (aged 76 and 78 years) both of whom suffered from hearing impairment and practically incessant musical hallucinations. Both patients were successfully treated with the acetylcholinesterase inhibitor rivastigmine. Based on these two case descriptions and an overview of studies describing the use of acetylcholinesterase inhibitors in similar patients, we discuss possible mechanisms and propose further research on the use of acetylcholinesterase inhibitors for musical hallucinations experienced in concordance with hearing loss.
Variation of Musca domestica L. acetylcholinesterase in Danish housefly populations
DEFF Research Database (Denmark)
Kristensen, Michael; Huang, Jing; Qiao, Chuan-Ling;
Anti-cholinesterase resistance is in many cases caused by modified acetylcholinesterase (MACE). A comparison was made of toxicological data and AChE activity gathered from 21 field populations and nine laboratory strains of houseflies, Musca domestica L., to elucidate the best way of generating d...
Optimization of RNA interference (RNAi) targeting acetylcholinesterase in the Southern cattle tick (Rhipicephalus microplus)
Acetylcholinesterase (AChE) is the primary target for organophosphate (OP) acaricides. OP resistant strains of the Southern cattle tick Rhipicephalus microplus have been identified and represent a major threat to the control of this important disease vector. R. microplus ticks possess at least three...
Insecticidal and Nematicidal Activities of Novel Mimosine Derivatives.
Nguyen, Binh Cao Quan; Chompoo, Jamnian; Tawata, Shinkichi
Mimosine, a non-protein amino acid, is found in several tropical and subtropical plants, which has high value for medicine and agricultural chemicals. Here, in continuation of works aimed to development of natural product-based pesticidal agents, we present the first significant findings for insecticidal and nematicidal activities of novel mimosine derivatives. Interestingly, mimosinol and deuterated mimosinol (D-mimosinol) from mimosine had strong insecticidal activity which could be a result of tyrosinase inhibition (IC50 = 31.4 and 46.1 μM, respectively). Of synthesized phosphoramidothionate derivatives from two these amino alcohols, two compounds (1a and 1b) showed high insecticidal activity (LD50 = 0.5 and 0.7 μg/insect, respectively) with 50%-60% mortality at 50 μg/mL which may be attributed to acetylcholinesterase inhibition. Compounds 1a and 1b also had strong nematicidal activity with IC50 = 31.8 and 50.2 μM, respectively. Our results suggest that the length of the alkyl chain and the functional group at the C₅-position of phosphoramidothionates derived from mimosinol and d-mimosinol are essential for the insecticidal and nematicidal activities. These results reveal an unexplored scaffold as new insecticide and nematicide.
Report on the surveillance of insecticidal resistance of Culex pipiens pallens in Hanzhuang%微山湖区韩庄镇淡色库蚊抗药性现状监测报告
Institute of Scientific and Technical Information of China (English)
赵方明; 杨秋兰
Culex pipiens pallens was collected from the Weishan Lake district and its insecticidal resistance was measured using a standard WHO bioassay. Cx. Pipiens pallens of Hanzhuang was resistant to five insecticides to some degree. The LC50 of Cx. Pipiens pallens to propoxur, DDVP, acetofenate, deltamethrin, and cypermethrin was 0. 474 1, 1. 401 2, 0. 242 0, 0. 003 4, and 0. 004 1 mg · L-1 , respectively. Cx. Pipiens pallens was most resistant to synthetic py-rethroid pesticides.%采用WHO生物测试法,测定了微山湖区韩庄镇淡色库蚊幼虫对常用杀虫剂的抗性水平.结果 显示韩庄镇淡色库蚊幼虫对残杀威、DDVP、三氯杀虫酯、溴氰菊酯、氯氰菊酯等5种常用杀虫剂的LC5.分别为0.474 1、1.401 2、0.242 0、0.003 4和0.004 1 mg· L-1,以菊酯类杀虫剂抗性最高.
济宁市蜚蠊侵害现况及抗药性调查%Study of cockroach infestation and insecticide resistance in the City of Jining
Institute of Scientific and Technical Information of China (English)
郝学安; 梁玉民
目的 掌握济宁市蜚蠊侵害现况及其抗药性、种群分布、季节消长和密度等情况. 方法 采用粘捕法捕捉蜚蠊,调查其种类及侵害程度;采用三角烧瓶药膜接触法检测蜚蠊抗药性. 结果 本次共回收有效粘蟑纸5400张,捕获蜚蠊715只,均为德国小蠊,其中成虫421只(占58.9%),若虫294只(占41.1%);蟑螂总密度为0.13只/张,侵害率为9.11%;蜚蠊密度以5~8月最高.场所蜚蠊密度以宾馆最高,侵害率医院最高,其次是餐饮和宾馆,居民区最低.济宁市德国小蠊对高效氯氰菊酯已产生高抗药性,对残杀威、溴氰菊酯和敌敌畏仍然敏感. 结论 济宁市宾馆、餐饮、医院为蜚蠊高侵害场所,并有向居民区快速扩散的趋势,必须加强对重点行业的管理,采取综合性防制措施,控制蜚蠊扩散和蔓延.%Objective To ascertain the level of cockroach infestation in the City of Jining and determine the insecticide resistance, population distribution, seasonal variations, and density of cockroaches. Methods Cockroaches caught with glue traps were used to investigate the types of cockroaches and extent of their infestation. An Erlenmeyer flask was used to expose cockroaches to a film of pesticide to test resistance. Results Five thousand four hundred sticky traps were collected and 715 cockroaches were caught. All were Blattella germanica, consisting of 421 adults (58. 9%) and 294 nymphs (41. 1%). Cockroach density was 0. 13 per trap and the rate of infestation was 9. 11%. Cockroach density peaked in May, June, July, and August. Infestation was worst in hospitals, followed by restaurants and hotels; density was lowest in residential areas. Cockroaches in the City of Jining were highly resistant to beta-cypermethrin but still suscepti-ble to propoxur, deltamethrin, and dichlorvos. Conclusion Hotels, restaurants, and hospitals were heavily infested, and infestation is rapidly spreading to residential areas. Management of key
The use of insecticides to control insect pests
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M Wojciechowska
Full Text Available Pesticides are used as plants protection products. Among those, insecticides serve as agents to control insects. When incorrectly applied, however these substances may negatively affect people's health and natural environment. Administration routes of insecticides depend on many factors and vary from spraying to fertilizers. These different methods influence how insects prey and how pests develop. Additionally, too frequent use of the same chemicals can lead to development of resistance of insects to these insecticides. In order to prevent occurrence of negative effects of insecticides on surroundings, the effects of these compounds should be studied
Resistance of Musca domestica to insecticides in Jiangxia district of Wuhan in 2010%武汉市江夏区2010年家蝇抗性水平调查
Institute of Scientific and Technical Information of China (English)
刘智; 董明娜; 彭建军; 唐作文; 田俊华; 陈晓敏; 吴太平
目的 了解武汉市江夏区家蝇对5种常见杀虫剂的抗性水平,为科学合理使用杀虫剂提供依据.方法 采用微量点滴法,检测江夏区家蝇野外种群对DDVP、甲基吡恶磷、高效氯氰菊酯、胺菊酯、氯氰菊酯5种杀虫剂的抗性水平.结果 2010年江夏区家蝇对DDVP和胺菊酯的抗性较低,LD50分别为0.19927和0.65550 μg/9,抗性倍数均在10倍以内,属低抗性(或耐药性);对氯氰菊酯和高效氯氰菊酯均已产生高抗性,LD50分别为0.81560和0.64850μg/♀,抗性倍数分别为177.3和231.6倍.结论 应根据抗药性调查结果科学合理使用杀虫剂,提倡综合防治.%Objective To provide a scientific basis for fly control by investigating resistance of Musca domestica to five common insecticides in Jiangxia district, Wuhan city. Methods The resistance of M. domestica to DDVP, azamethiphos, beta -cypermethrin, tetramethrin and cypermethrin were measured by topical application methods. Results M. domestica had low resisiteance to DDVP (LD50=0.199 27 μg/ ♀) and beta-cypermethrin (LD50=0.655 50μg/ ♀), with the resistance ratio below 10-fold. M. domestica had devoloped high resistance to cypermethrin (LD50=0.815 60 μg/ ♀) and propoxur (LD50=0.648 50 μg/ ♀), and the resistances ratio to the two insecticides was 177.3 and 231.6 respectively. Conclusion It is essential to use insecticides reasonably based on researches of M. domestica's resistance. It is also important to develop comprehensive prevention and control strategies.
Surface display of recombinant Drosophila melanogaster acetylcholinesterase for detection of organic phosphorus and carbamate pesticides.
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Jingquan Li
Full Text Available Acetylcholinesterase (AChE is commonly used for the detection of organophosphate (OP and carbamate (CB insecticides. However, the cost of this commercially available enzyme is high, making high-throughput insecticide detection improbable. In this study we constructed a new AChE yeast expression system in Saccharomyces cerevisiae for the expression of a highly reactive recombinant AChE originating from Drosophila melanogaster (DmAChE. Specifically, the coding sequence of DmAChE was fused with the 3'-terminal half of an α-agglutinin anchor region, along with an antigen tag for the detection of the recombinant protein. The target sequence was cloned into the yeast expression vector pYes-DEST52, and the signal peptide sequence was replaced with a glucoamylase secretion region for induced expression. The resultant engineered vector was transformed into S. cerevisiae. DmAChE was expressed and displayed on the cell surface after galactose induction. Our results showed that the recombinant protein displayed activity comparable to the commercial enzyme. We also detected different types of OP and CB insecticides through enzyme inhibition assays, with the expressed DmAChE showing high sensitivity. These results show the construction of a new yeast expression system for DmAChE, which can subsequently be used for detecting OP and CB insecticides with reduced economic costs.
Determination and analysis on resistance to 5 insecticides of musca domestica in Haidian District of Beijing%北京市海淀区家蝇对5种杀虫剂的抗性测定和分析
Institute of Scientific and Technical Information of China (English)
侯威远; 王磊; 赵岩; 蔡伟
Objective To understand the resistance of musca domestica to 5 common insecticides in Haidian District , and provide evidence for rational use of drugs. Method Determine the resistance by topical application method. Results The resistance indexs of musca domesticas to deltamethrin, cypermethrin, chlorpyrifos, acephate and propoxur were 40. 10, 46. 48, 10. 36, 15. 33 and 5. 43 , respectively. Conclusions The collected musca domesticas in Haidian District presented obvious resistance to the five insecticides, and the resistance level from high to low was cypermethrin, deltamethrin, acephate, chlorpyrifos, and propoxur, respectively.%目的 了解北京市海淀区现场品系家蝇对5种常用杀虫剂的抗性水平,为合理选择用药提供依据.方法 采用点滴法测定抗性水平.结果 现场品系家蝇对溴氰菊酯、氯氰菊酯、毒死蜱、乙酰甲胺磷和残杀威的抗性系数分别为40.10,46.48,10.36,15.33和5.43.结论 北京市海淀区现场品系家蝇对5种杀虫剂均产生了明显的抗性,但抗性的程度不同,从高到低依次为:氯氰菊酯、溴氰菊酯、乙酰甲胺磷、毒死蜱和残杀威.
抗高效氯氰菊酯家蝇对常用杀虫剂的敏感性研究%Susceptibility of beta cypermethrin-resistant Musca domestica to common used insecticides
Institute of Scientific and Technical Information of China (English)
张莹; 唐勇; 孙炳欣; 张丽梅
Objective To study the susceptibility of beta cypermethrin-resistant Musca dornestica to common used insecticides and supply evidence for using insecticides reasonably. Methods Topical application method. Results The housefly' s resistant ratios to clorpyrifos, propoxur, beta cypermethrin, allethrin, cyhalothrin, DDVP folds respectively were 0. 85 ,8. 75 ,153. 79,35. 59,679. 71,0. 09 respectively. Conclusion If the housefly yields resisitance to beta cypermethrin, exchanging or mixing used of organophosphate insecticdes may be a better method.%目的 探讨抗高效氯氰菊酯家蝇对常用杀虫剂的敏感性,为合理使用杀虫剂提供依据.方法 采用微量点滴法.结果 毒死蜱、残杀威、高效氯氰菊酯、胺菊酯、三氟氯氰菊酯、敌敌畏对家蝇的抗性系数分别为0.85、8.75、153.79、35.59、679.71、0.09.结论 当家蝇对高效氯氰菊酯产生抗性以后,不宜继续使用其他拟除虫菊酯杀虫剂,而应换用或混用有机磷类杀虫剂.
国际航行船舶携带德国小蠊抗药性调查%Investigation on insecticide resistance of Blattella germanica collected from international voyage ships
Institute of Scientific and Technical Information of China (English)
周炯林; 丁言良; 胡攀; 林纲
目的 了解国际航行船舶携带的德国小蠊抗药性情况,为口岸防治合理用药提供科学依据.方法 采集国际航行船舶上孳生的德国小蠊自然种群,带回实验室繁育,培养1代后,取2~3周龄雄性成虫,用药膜接触法测定其对丙烯菊酯、溴氰菊酯、敌敌畏、仲丁威、残杀威、毒死蜱、高效氯氰菊酯7种杀虫剂的抗性倍数.结果 采自3艘国际航行船舶的德国小蠊对7种杀虫剂的抗性依次为2.54~5.56、2.18~5.14、3.98~5.87、1.57~1.91、0.83~1.27、1.06~1.59、2.89~3.93倍.结论 3艘国际航行船舶携带的德国小蠊对菊酯类及有机磷类杀虫剂敌敌畏已产生耐药性或抗药性,对氨基甲酸酯类杀虫剂及毒死蜱较为敏感,口岸防治德国小蠊可采用氨基甲酸酯类杀虫剂.%Objective To evaluate the insecticide resistance of Blattella germanica collected from international voyage ships. Methods B. germanicas were collected from international voyage ships and bred in laboratory, male insects of the first offspring aged 2-3 weeks were collected to evaluate their resistance to allethrin, deltamethrin, DDVP, fenobucarb, propoxur, chlorpyrifos, and decamethrim. The resistance was determined by the insecticide film contact method. Results The resistance level of B. germanica from three ships against allethrin, deltamethrin, DDVP, fenobucarb, propoxur, chlorpyrifos, and decamethrim was 2.54-5.56, 2.18-5.14, 3.98-5.87, 1.57-1.91, 0.83-1.27, 1.06-1.59 and 2.89-3.93 times of the susceptible strain, respectively. Conclusion The B. germanica from the three ships have developed different degrees of resistance to pyrethroid insecticides and DDVP, but still susceptible to carbamate insecticides and chlorpyrifos. The carbamate insecticides can be used for controlling cockroaches in ports.
Detecção e monitoramento da resistência do tripes Frankliniella occidentalis ao inseticida espinosade Detection and monitoring of resistance to the insecticide spinosad in the thrips Frankliniella occidentalis
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Débora Soller Rais
pests in greenhouses, especially on ornamental plants and vegetables. Among the problems faced by farmers are the difficulties in the control of this pest with the use of insecticides because of its preference for the inner parts of the flowers and the evolution of resistance to agrochemicals. The objective of this research was to characterize the spinosad resistance in F. occidentalis and to assess the frequency of resistant insects in commercial chrysanthemum fields from several counties in the state of São Paulo (SP. Selections for resistance to spinosad were performed under laboratory conditions, using a population of F. occidentalis collected in 2007 in a commercial chrysanthemum field in Campinas (SP. In the course of seven selections for resistance, the LC50 of spinosad increased from 8.41 mg a.i. L-1 to 1,111 mg a.i. L-1. Comparing the resistant (R and the susceptible (S strains, the resistance ratio (LC50 R / LC50 S reached values up to 280-folds. A discriminating concentration of 98 mg a.i. L-1 was established for monitoring the spinosad resistance in F. occidentalis. The survey was conducted by collecting 19 populations of thrips in commercial chrysanthemum fields in the state of São Paulo. The bioassays were conducted with second ínstar nymphs of F. occidentalis, placed in bean leaf disc arenas. The spinosad was sprayed at the discriminating concentration on the nymphs of thrips, using a Potter spray tower. The results indicated high variability in the susceptibility to spinosad among F. occidentalis populations. Populations with up to 40.7% of resistant insects were found. This is the first report on spinosad resistance in F. occidentalis in Brazil.
Detecção e monitoramento da resistência do tripes Frankliniella occidentalis ao inseticida espinosade Detection and monitoring of resistance to the insecticide spinosad in the thrips Frankliniella occidentalis
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Débora Soller Rais
pests in greenhouses, especially on ornamental plants and vegetables. Among the problems faced by farmers are the difficulties in the control of this pest with the use of insecticides because of its preference for the inner parts of the flowers and the evolution of resistance to agrochemicals. The objective of this research was to characterize the spinosad resistance in F. occidentalis and to assess the frequency of resistant insects in commercial chrysanthemum fields from several counties in the state of São Paulo (SP. Selections for resistance to spinosad were performed under laboratory conditions, using a population of F. occidentalis collected in 2007 in a commercial chrysanthemum field in Campinas (SP. In the course of seven selections for resistance, the LC50 of spinosad increased from 8.41 mg a.i. L-1 to 1,111 mg a.i. L-1. Comparing the resistant (R and the susceptible (S strains, the resistance ratio (LC50 R / LC50 S reached values up to 280-folds. A discriminating concentration of 98 mg a.i. L-1 was established for monitoring the spinosad resistance in F. occidentalis. The survey was conducted by collecting 19 populations of thrips in commercial chrysanthemum fields in the state of São Paulo. The bioassays were conducted with second ínstar nymphs of F. occidentalis, placed in bean leaf disc arenas. The spinosad was sprayed at the discriminating concentration on the nymphs of thrips, using a Potter spray tower. The results indicated high variability in the susceptibility to spinosad among F. occidentalis populations. Populations with up to 40.7% of resistant insects were found. This is the first report on spinosad resistance in F. occidentalis in Brazil.
Synthesis of Novel Chalcones as Acetylcholinesterase Inhibitors
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Thanh-Dao Tran
Full Text Available A new series of benzylaminochalcone derivatives with different substituents on ring B were synthesized and evaluated as inhibitors of acetylcholinesterase. The study is aimed at identification of novel benzylaminochalcones capable of blocking acetylcholinesterase activity for further development of an approach to Alzheimer's disease treatment. These compounds were produced in moderate to good yields via Claisen-Schmidt condensation and subjected to an in vitro acetylcholinesterase inhibition assay, using Ellman's method. The in silico docking procedure was also employed to identify molecular interactions between the chalcone compounds and the enzyme. Compounds with ring B bearing pyridin-4-yl, 4-nitrophenyl, 4-chlorophenyl and 3,4-dimethoxyphenyl moieties were discovered to exhibit significant inhibitory activities against acetylcholinesterase, with IC50 values ranging from 23 to 39 µM. The molecular modeling studies are consistent with the hypothesis that benzylaminochalcones could exert their effects as dual-binding-site acetylcholinesterase inhibitors, which might simultaneously enhance cholinergic neurotransmission and inhibit β-amyloid aggregation through binding to both catalytic and peripheral sites of the enzyme. These derivatives could be further developed to provide novel leads for the discovery of new anti-Alzheimer drugs in the future.
北京市朝阳区德国小蠊对杀虫剂抗性分布情况调查%Study on geographic distribution of insecticides resistance of German cockroaches (Blattella germanica) in Chaoyang district, Beijing
Institute of Scientific and Technical Information of China (English)
葛军旗; 张洪江; 张政; 王仲华; 孟凤霞
Objective To know the resistance situation and its geographic distribution of German cockroaches (Blattella germanica) in Chaoyang district. Methods German cockroaches were trapped from eight sites belonging to different geographic zone. The insecticides film contact method was used to the detection of resistance. The resistance level of German cockroach from different sites was analyzed by average linkage method. Results There was significant difference among the resistance level of cockroach to seven insecticides (X~2=26.880, P=0.000). It had the highest resistance to organophosphorus insecticides (X~2=20.494, P=0.000). The resistance levels of cockroach from 8 sites were also significantly different (X~2=29.143, P=0.000), which could be classified into four groups by duster analysis. Conclusion The resistance of cockroach to insecticides was different in different areas in Chaoyang district, so the same control method.%目的 了解朝阳区不同区域德国小蠊对杀虫剂的抗性水平及分布情况.方法 按行政区划选定8个取样点,采集每个取样点的德国小蠊自然种群,带回实验室繁育,用药膜接触法测定其对7种杀虫剂的抗性系数.比较德国小蠊对7种杀虫剂的抗性程度差别;比较8个取样点德国小蠊种群的抗性差别,并以类平均法做聚类分析.结果 德国小蠊对7种杀虫剂的抗性程度差异具有统计学意义(X~2=26.880,P=0.000),对有机磷类杀虫剂的抗性最高(X~2=20.494,P=0.000);8个取样点德国小蠊种群对杀虫剂抗性水平差异亦有统计学意义(X~2=29.143,P=0.000),根据聚类分析结果和专业知识可将其划分为4类.结论 朝阳区德国小蠊对杀虫剂存在地理位置差别,抗性监测和指导用药时"以点代面"做法不可取.
Acetylcholinesterase Inhibition by Biofumigant (Coumaran from Leaves of Lantana camara in Stored Grain and Household Insect Pests
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Yallappa Rajashekar
Full Text Available Recent studies proved that the biofumigants could be an alternative to chemical fumigants against stored grain insect pests. For this reason, it is necessary to understand the mode of action of biofumigants. In the present study the prospectus of utilising Lantana camara as a potent fumigant insecticide is being discussed. Inhibition of acetylcholinesterase (AChE by Coumaran, an active ingredient extracted from the plant L. camara, was studied. The biofumigant was used as an enzyme inhibitor and acetylthiocholine iodide as a substrate along with Ellman's reagent to carry out the reactions. The in vivo inhibition was observed in both dose dependent and time dependent in case of housefly, and the nervous tissue (ganglion and the whole insect homogenate of stored grain insect exposed to Coumaran. The possible mode of action of Coumaran as an acetylcholinesterase inhibitor is discussed.
Positive correlation of methamidophos resistance between Lipaphis erysimi and Diaeretilla rapae and effects of methamidophos ingested by host insect on the parasitoid
Institute of Scientific and Technical Information of China (English)
Gang Wu; Yong-Wen Lin; Tadashi Miyata; Shu-Ren Jiang; Lian-Hui Xie
Temporal and spatial correlated variations on the methamidophos resistance and biomolecular rate constant of acetylcholinesterase to insecticides were found between the turnip aphid, Lipaphis erysimi and its endoparasitoid, Diaeretilla rapae, collected from field colonies and an insecticide-free field insectarium in Fujian, China. Compared to the related susceptible iusectarium population, L. erysimi and D. rapae displayed 7.4-29.2- and 2.6-9.2-fold resistance ratios, respectively. In addition, two populations of L. erysimi with different methamidophos resistance levels, that is, a field (with 5.8-fold resistance ratio) and an insectarium population, were used to study the effects of methamidophos ingested by the host insect on D. rapae development. The percentage of D. rapae cocoon formation decreased significantly when the parasitized L. erysimi were fed on cauliflower leaves treated with methamidophos at lethal concentration dosages 10 (LC10) or LC50. At LC50 dosages the percentage of D. rapae cocoon formation and adult emergence decreased significantly. When the parasitized L. erysimi were fed on methamidophos at LC50 dosage, no D. rapae cocoons were found. When the field or insectarium L. erysimi were treated with methamidophos at LC10, the susceptibility to methamidophos in the adult D. rapae emerged from the treated host insect was similar to the control. However, the susceptibility to methamidophos in the adult D. rapae became lower than the control when the host insects were treated at LC50 dosages. The data thus suggested that the methamidophos ingested by the host insect L. erysimi could be an important factor in the endoparasitoids' insecticide resistance development. The natural selectivity would favor the parasitoids that had developed an insensitivity to the insecticide(s).
德国小蠊对3种常用杀虫剂的抗性调查%Resistance of Blattella germanica to three commonly used insecticides in Baoshan district of Shanghai
Institute of Scientific and Technical Information of China (English)
目的 了解2010年上海市宝山区的德国小蠊对溴氰菊酯、残杀威和高效氯氰菊酯的抗药性,以便科学合理使用杀虫剂.方法 药膜接触法.结果 上海市宝山区现场品系德国小蠊对溴氰菊酯、残杀威、高效氯氰菊酯的KT50分别为48.86、25.39、34.79 min,其抗性系数分别是敏感品系德国小蠊的9.18、1.83、6.09倍.结论 上海市宝山区现场品系德国小蠊对溴氰菊酯和高效氯氰菊酯已产生抗药性,对残杀威尚处敏感水平.%Objective To investigate the resistance of Blattella germanica to deltamethrin, propoxur, beta-eyper-methrin in Baoshan district of Shanghai in 2010, and give guidance to use insecticides scientifically. Methods The method of contact with chemical insecticides in jar was used. Results The KT50 of field-collected population of B. Germanica to deltamethrin, propoxur, beta-cypermethrin were 48. 86, 25. 39 and 34. 79 min respectively. The resistance ratios to deltamethrin, propoxur, beta-cypermethrin were 9.18, 1. 83 and 6. 09 respectively. Conclusion The field-collected population of B. Germanica from Baoshan district of Shanghai have developed resistance to deltamethrin and beta-cypermethrin, but they are susceptible to propoxur.
Control of pyrethroid and DDT-resistant Anopheles gambiae by application of indoor residual spraying or mosquito nets treated with a long-lasting organophosphate insecticide, chlorpyrifos-methyl
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Chabi Joseph
Full Text Available Abstract Background Scaling up of long-lasting insecticidal nets (LLINs and indoor residual spraying (IRS with support from the Global Fund and President's Malaria Initiative is providing increased opportunities for malaria control in Africa. The most cost-effective and longest-lasting residual insecticide DDT is also the most environmentally persistent. Alternative residual insecticides exist, but are too short-lived or too expensive to sustain. Dow Agrosciences have developed a microencapsulated formulation (CS of the organophosphate chlorpyrifos methyl as a cost-effective, long-lasting alternative to DDT. Methods Chlorpyrifos methyl CS was tested as an IRS or ITN treatment in experimental huts in an area of Benin where Anopheles gambiae and Culex quinquefasiactus are resistant to pyrethroids, but susceptible to organophosphates. Efficacy and residual activity was compared to that of DDT and the pyrethroid lambdacyalothrin. Results IRS with chlorpyrifos methyl killed 95% of An. gambiae that entered the hut as compared to 31% with lambdacyhalothrin and 50% with DDT. Control of Cx. quinquefasciatus showed a similar trend; although the level of mortality with chlorpyrifos methyl was lower (66% it was still much higher than for DDT (14% or pyrethroid (15% treatments. Nets impregnated with lambdacyhalothrin were compromized by resistance, killing only 30% of An. gambiae and 8% of Cx. quinquefasciatus. Nets impregnated with chlorpyrifos methyl killed more (45% of An gambiae and 15% of Cx. quinquefasciatus, but its activity on netting was of short duration. Contact bioassays on the sprayed cement-sand walls over the nine months of monitoring showed no loss of activity of chlorpyrifos methyl, whereas lambdacyhalothrin and DDT lost activity within a few months of spraying. Conclusion As an IRS treatment against pyrethroid resistant mosquitoes chlorpyrifos methyl CS outperformed DDT and lambdacyhalothrin. In IRS campaigns, chlorpyrifos methyl CS should
昆虫抗药性机理:行为和生理改变及解毒代谢增强%Behavioral change, physiological modification, and metabolic detoxification: mechanisms of insecticide resistance
Institute of Scientific and Technical Information of China (English)
刘喃喃; 朱芳; 徐强; Julia W.PRIDGEON; 高希武
Insecticide resistance is "the development of an ability in a strain of some organisms to tolerate doses of a toxicant which would prove lethal to a majority of individuals in a normal population of the same species".Mechanisms of resistance, such as behavioral change, physiological modification or metabolic detoxification, decrease the effective dose available at the target site. Behavioral resistance is defined as any behavior that reduces an insect's exposure to toxic compounds or that allows an insect to survive in an environment that is harmful and/or fatal to the majority of insects. Physiological modification mechanisms permit insects to survive lethal doses of a toxicant through decreased penetration of insecticides, increased sequestration/storage of insecticides, and accelerated excretion of insecticides. Metabolic detoxification is conferred by cytochrome P450 monooxygenases (cytochrome P450s),hydrolases, and glutathione transferases (GSTs). Cytochrome P450s constitute the largest gene superfamily and are critical for the detoxification and/or activation of xenobiotics and the metabolism of endogenous compounds. Increased P450-mediated detoxification has been found in many insect species, resulting in enhanced insecticide resistance.Glutathione transferases (GSTs) are soluble dimeric proteins involved in the metabolism, detoxification, and excretion of a large number of endogenous and exogenous compounds. Elevated GST activities have been implicated in resistance in many insect species. Hydrolases or esterases, a group of heterogeneous enzymes, have been identified as the active agents promoting hydrolase-mediated resistance that protect insects by either binding and sequestering insecticides through overproduction of proteins, or enhancing the metabolism of insecticides through increased enzyme activities.%杀虫剂抗性是指"生物的一个品系发展了对该生物正常种群中大多数个体具有致死作用剂量的杀虫药剂的能力".行�
Generation of insect-resistant and glyphosate-tolerant rice by introduction of a T-DNA containing two Bt insecticidal genes and an EPSPS gene
Institute of Scientific and Technical Information of China (English)
Qi-chao ZHAO; Ming-hong LIU; Xian-wen ZHANG; Chao-yang LIN; Qing ZHANG; Zhi-cheng SHEN‡
题目:转Cry1Ac、Cry1Ig和EPSPS基因水稻及其抗虫、抗草甘膦活性鉴定 目的:获得具有高水平表达 Cry1Ac、Cry1Ig和 EPSPS基因并且具有抗虫、抗草甘膦活性的转基因水稻株。 创新点:Cry1Ig为新发现的苏云金杆菌(Bt)杀虫基因;Cry1Ig与 Cry1Ac共同使用有利于延缓害虫产生对Bt杀虫蛋白抗性。 方法:将Cry1Ac、Cry1Ig和EPSPS(G10)基因的表达框依次插入到同一转移 DNA(T-DNA)中,再将此 T-DNA 利用农杆菌介导法转化到水稻中。从转基因后代中,利用蛋白质印迹法(Western blot)、DNA印迹法(Southern blot)和热不对称交错聚合酶链式反应(TAIL-PCR)技术,筛选出能够高水平表达上述三个基因以及 T-DNA 单拷贝插入并且未发生明显插入突变的转化株。对于筛选到的转化株,利用 Western blot进一步分析 Cry1Ac、Cry1Ig和 G10基因的表达水平;使用酶联免疫吸附测定(ELISA)检测Cry1Ac的表达量;使用棉铃虫、二化螟和稻纵卷叶螟为对象,测定转基因水稻的抗虫活性;使用草甘膦喷施法,测定转基因水稻的抗草甘膦活性。最后,在大田试验中,考察转基因水稻与非转基因水稻的基本农艺性状,观察 T-DNA 的插入是否对转基因水稻的生长产生明显的影响。 结论:本实验最终获得具有高水平表达Cry1Ac、Cry1Ig和G10基因以及T-DNA单拷贝插入并且未引起明显变化的转化株 GAI-14。GAI-14对棉铃虫、二化螟、稻纵卷叶螟以及草甘膦均具有明显的抗性。田间试验表明 GAI-14在基本农艺性状上与非转基因水稻无明显差异。%Insect resistance and glyphosate tolerance have been two of the most important traits in the genetic improvement of various crops. In this study, two Bacil us thuringiensis (Bt) insecticidal genes, Cry1Ac and Cry1Ig, and a modified glyphosate-tolerant 5-enolpyruvylshikimate-3-phosphate
Delayed action insecticides and their role in mosquito and malaria control.
Wang, Chuncheng; Gourley, Stephen A; Liu, Rongsong
There is considerable interest in the management of insecticide resistance in mosquitoes. One possible approach to slowing down the evolution of resistance is to use late-life-acting (LLA) insecticides that selectively kill only the old mosquitoes that transmit malaria, thereby reducing selection pressure favoring resistance. In this paper we consider an age-structured compartmental model for malaria with two mosquito strains that differ in resistance to insecticide, using an SEI approach to model malaria in the mosquitoes and thereby incorporating the parasite developmental times for the two strains. The human population is modeled using an SEI approach. We consider both conventional insecticides that target all adult mosquitoes, and LLA insecticides that target only old mosquitoes. According to linearised theory the potency of the insecticide affects mainly the speed of evolution of resistance. Mutations that confer resistance can also affect other parameters such as mean adult life span and parasite developmental time. For both conventional and LLA insecticides the stability of the malaria-free equilibrium, with only the resistant mosquito strain present, depends mainly on these other parameters. This suggests that the main long term role of an insecticide could be to induce genetic changes that have a desirable effect on a vital parameter such as adult life span. However, when this equilibrium is unstable, numerical simulations suggest that a potent LLA insecticide can slow down the spread of malaria in humans but that the timing of its action is very important.
Resistance of Blattella germanica to common used insecticides in Yancheng city%盐城市区德国小蠊对常用杀虫剂的抗药性测定
Institute of Scientific and Technical Information of China (English)
徐慧; 陈胤忠
目的 测定盐城市区蟑螂对溴氰菊酯、敌敌畏、残杀威、乙酰甲胺磷、高效氯氰菊酯5种杀虫剂的抗药性,以便通过抗药性水平在全市开展有效、科学的灭蟑工作.方法 采用500 ml三角烧瓶药膜接触法,测定德国小蠊半数击倒时间.结果 现场德国小蠊对上述5种杀虫剂的抗性系数分别为0.16、5.43、0.0013、1.13和11.03.盐城市区德国小蠊对高效氯氰菊酯为高抗性,对敌敌畏为中度抗性,对乙酰甲胺磷为低度抗性,而对溴氰菊酯、残杀威敏感.结论 应该根据抗药性合理选择杀虫剂,以提高蟑螂的防治效果.%Objective To determine resistance of Blattella germanica to deltamethrin, dichlorvos , propoxur, acephate,high effect cypermethrin in Yancheng city,and develop scientifical and reasonable work of killing cockroaches. Methods Using the method of medicine membrane - touching in 500 ml flask to find out the KT50 of Blattella germanica. Results The resistance index of field collected strains of Blattella germanica to above mentioned insecticides were 0. 16,5.43.0.0013,1. 13 and 11.03. Blattella germanica in Yancheng city showed high resistance to high effect cypermethrin, middle resistance to dichlorvos ,low resistance to acephate and sensitive to deltamethrin and propoxur. Conclusion It is necessary to select appropriate insecticides according to the situation of resistance so as to improve cockroach control effect.
Insecticide Compendium. MP-29.
Spackman, Everett W.; And Others
This document presents information on most of the known insecticides and their general usage, toxicity, formulation, compound type, manufacturers, and the chemical, trade and common names applied to each compound. (CS)
Insecticides and Biological Control
Furness, G. O.
Use of insecticides has been questioned due to their harmful effects on edible items. Biological control of insects along with other effective practices for checking spread of parasites on crops are discussed. (PS)
Directory of Open Access Journals (Sweden)
E.K. Hartwig
Full Text Available An insecticide is a chemical used to kill insects. Insect control can also include other materials such as repellents, oils, antifeedants and attractants. Ideally, an insecticide would effectively control any target insect exposed to it and would be harmless to man and his domestic animals. It would also be readily available in necessary quantitie s , s table chemically, noninflammable, easily prepared and applied, noncorrosive, non-staining, and would have no undesirable odour.
Investigation of resistance of Musca domestica to insecticides in the four areas of Shaanxi province%陕西省不同地区家蝇抗药性调查
Institute of Scientific and Technical Information of China (English)
吕文; 霍丽霞; 孙养信
目的 了解陕西省安康、渭南、宝鸡、铜川市家蝇抗药性情况,指导科学合理地使用杀虫剂.方法 现场试虫采自城区蝇类孳生场所,敏感试虫为实验室不接触杀虫剂的家蝇,采用点滴法,以丙酮为对照,检查不同药物浓度对应的试虫死亡率,用POLO软件分析获得半数致死量(LD50).结果 实验室家蝇对敌敌畏、双硫磷、DDT、残杀威、高效氯氰菊酯、溴氰菊酯、氯氰菊酯和氯菊酯的LD50依次为0.004、0.113、0.010、0.214、0.003 07、0.000 63、0.003和0.013μg/只.安康、渭南、宝鸡、铜川市的家蝇对8种常用杀虫剂均产生了不同程度的抗药性,对敌敌畏、双硫磷、DDT、残杀威、高效氯氰菊酯、溴氰菊酯、氯氰菊酯和氯菊酯的LD50分别为0.051~0.301、4.429~14.480、1.259~1.573、13.579~33.556、0.024~0.303、0.017~0.046、0.047~0.269和0.016~0.053 μg/只;8种杀虫剂的平均LD50为0.028~23.549μg/只,抗性倍数为2.54~140.20倍,以DDT最高,氯菊酯最低.结论 应采取科学的方法使用杀虫剂,延缓家蝇抗性增长.%Objective To understand the resistance of Musca domestica to insecticides in the four areas of Shaanxi province for providing evidence for scientific application of insecticides. Methods Insects were collected in the fields in urban areas where flies bred and sensitive insects were reared in laboratory without exposure to insecticides. Topical dropping method was used to determine the death rate by different drug concentrations, with LD50 obtained by POLO software analysis. Results The LD50 of sensitive insects to DDVP, temephos, DDT, propoxur, beta-cypermethrin, deltamethrin, cypermethrin and permethrin was 0.004, 0.113, 0.010, 0.214, 0.003 07, 0.000 63, 0.003 and 0.013 μg/♀ , respectively. Different degrees of resistance of M. domestica to the eight commonly used insecticides were observed in Ankang, Weinan, Baoji, Tongchuan city of Shaanxi province. The LD50 of M
按蚊对5种常用杀虫剂的抗药性现场调查研究%Resistance of Anopheles to 5 kinds of common used insecticides in Dalian city
Institute of Scientific and Technical Information of China (English)
宋丽华; 周祎; 齐上; 庞为; 吴炜; 张衡谦; 邓凯
Objective To investigate the resistance of adult mosquito of Anopheles to DDT, deltamethrin, prop-oxur,beta cypermethrin and permethrin in Dalian and provide scientific evidence for its control. Methods Anopheles were captured with filter contact method recommended by WHO and the knockdown rate,the knockdown time and 24 h mortality were observed. Results The knockdown time of the first Anopheles to DDT,deltamethrin,propoxur, beta cypermethrin,permethrin in Dalian were 6,6,4,8,8 min. Death rate of discrimination dosages:deltamethrin 91. 30% , propoxur 89.48% ,permethrin 84.93% ,beta cypermethrin 80.43% ,they were initially resistant group( M) ;DDT 50. 60% was a resistant group(R). Conclusion Resistance should be monitored regularly. Integrated use of insecticides and other methods for control of Anopheles should be carried out according to local conditions. The occurrence and development of resistance could be prevented and reduced by scientific and rational use of insecticides.%目的 调查大连市媒介按蚊成蚊对DDT、溴氰菊酯、残杀威、高效氯氰菊酯、氯菊酯抗药性,为合理使用杀虫剂提供科学依据.方法 采用WHO成蚊滤纸接触筒法,观察区分剂量开始击倒时间、不同时间击倒率和24 h死亡率,根据死亡率判定抗性级别.结果 大连市媒介按蚊成蚊对DDT、溴氰菊酯、残杀威、高效氯氰菊酯、氯菊酯首只蚊虫击倒时间分别为6、6、4、8、8 min.区分剂量24h死亡率:依次为溴氰菊酯91.30%、残杀威89.48%、氯菊酯84.93%、高效氯氰菊酯80.43%为初步抗性群体(M);DDT 50.60%为抗性群体(R).结论 应加强媒介按蚊抗药性监测,并根据具体情况,采用适宜防蚊方法,合理地使用杀虫剂,预防或减缓媒介按蚊对杀虫剂抗药性的产生和发展.
Methods for field detection of resistance to temephos in simuliids. Larval esterase level and topical application of the insecticide to adults
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Carlos Fernando S. de Andrade
Full Text Available Two practical field methods for indirect detection of simuliid populations resistant to temephos are proposed. The first is based on high esterase activity in resistant larvae and involves adaptations of a filter paper test in which faintly stained spots indicate susceptible populations and strongly stained ones reveal populations resistant to temephos. The second is based on the resistance to the larvicide when adults are topically exposed, and involves the use of diagnostic doses obtained by the comparison between the LD50 for susceptible and resistant populations. The relevance of such methods is discussed in order to help resistance detection in Simulium pertinax Kollar control programmes.
Resistance of rice stem borer(Chilo suppressalis Walker) to insecticides in Cixi, Zhejiang Province%浙江慈溪水稻二化螟抗药性研究初报
Institute of Scientific and Technical Information of China (English)
胡仕孟; 谢士杰; 徐善刚; 毛国孟
采用毛细管点滴法,测定了浙江慈溪水稻二化螟对4类9种杀虫剂的抗性和敏感性水平。结果表明,该地的二化螟对杀虫双、杀虫单、杀虫安、甲胺磷4种杀虫剂均已产生高水平抗性,对杀螟硫磷已产生中抗,对甲基对硫磷、三唑磷、氰戊菊酯则仍保持敏感水平,同时发现二化螟对氟虫腈极为敏感,对6龄幼虫的LD50仅0.3833μg/g。%Resistance level of rice stem borer (Chilo suppressalis Walker) to aeveral conventional insecticides was tested with topical application in Cixi, Zhejiang Province. Results showed high level of resistance appeared to dimhypo and other two derivatives,methamidophos; moderate level of resistance to fenitrothion; but parathionmethyl, triazophos, fenvalerate remained susceptible. The borer was discovered to be extremely susceptible to fipronil with LD50 to 6-instar larvae being 0.3833 μg/g.
Resistance Mechanisms of Anopheles stephensi (Diptera: Culicidae to Temephos
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Aboozar Soltani
Full Text Available Background: Anopheles stephensi is a sub-tropical species and has been considered as one of the most important vector of human malaria throughout the Middle East and South Asian region including the malarious areas of southern Iran. Current reports confirmed An. stephensi resistance to temephos in Oman and India. However, there is no comprehensive research on mechanisms of temephos resistance in An. stephensi in the literature. This study was designed in order to clarify the enzymatic and molecular mechanisms of temephos resistance in this species.Methods: Profile activities of α- and ß-esterases, mixed function oxidase (MFO, glutathione-S-transferase (GST, insensitive acetylcholinesterase, and para-nitrophenyl acetate (PNPA-esterase enzymes were tested for An. stephensi strain with resistance ratio of 15.82 to temephos in comparison with susceptible strain.Results: Results showed that the mean activity of α-EST, GST and AChE enzymes were classified as altered indicating metabolic mechanisms have considerable role in resistance of An. stephensi to temephos. Molecular study using PCR-RFLP method to trace the G119S mutation in ACE-1 gene showed lack of the mutation responsible for organophosphate insecticide resistance in the temephos-selected strain of An. stephensi.Conclusion: This study showed that the altered enzymes but not targets site insensitivity of ACE-1 are responsible for temephos resistance in An. stephensi in south of Iran.
Investigation of flies population composition and its insecticide resistance in Lianyungang%连云港地区蝇类种群构成及其抗性调查研究
Institute of Scientific and Technical Information of China (English)
魏春清; 周日辉; 赵兴; 崔凤云; 邱成娟; 张琦
目的 研究并掌握连云港地区蝇类的构成、发生、发展规律以及抗性的发生情况.方法 采用诱蝇笼法进行蝇的调查研究,诱饵为醋与红糖的混合物;采用点滴法进行抗药性测试.结果 连云港地区蝇类隶属4科12属22种.每年4-11月均有蝇类发生,蝇密度基本呈双峰型,9月为最高,6、8月为次高,家蝇为优势种,占蝇类总体的57.7%.农贸市场蝇密度最高,其次为绿化带;家蝇对氯菊酯、氯氰菊酯、残杀威产生了高抗性.结论 连云港地区的蝇类每年4 -11月份均有活动,优势种为家蝇.其对氯菊酯、氯氰菊酯、残杀威均产生了高抗性,对敌敌畏也产生了中抗性.%Objective To study and understand the flies' proportion,regulation of occuring and resistance to common used insecticides in Lianyungang city. Methods Using the luring cage for investigating the flies with the mixed sugar and vinegar,examming the resistance with drop way for common used insecticides. Results The files in Lianyungang belonged to 22 species , 12 genus, 4 families. The flies occurred and were active between April to November annually with two peaks in a year. The highest peak occurred in September, and the second in June and August. 57. 7% of all flies were Musca domestica. The area of highest flies density was at farm product market,followed by trees and lawn. The Musca domestica had high resistance to permethrin, cypermethrin and propoxur. Conclusion The flies occur between April to November annually in Lianyungang district. The major species is Musca domestica with high resistance to permethrin, cypermethrin and propoxur.
淡色库蚊幼虫对7种杀虫剂的敏感性和抗性调查%Survey on the sensitivity and resistance of Culex pipiens pallens larva to seven kinds of insecticide
Institute of Scientific and Technical Information of China (English)
陈志龙; 陈东亚; 刘慧; 杨维芳; 褚宏亮; 刘大鹏; 张爱军; 徐燕; 孙俊
Objective To investigate the resistance of Culex pipiens pallens larva to insecticides in Jiangsu Province and provide scientific evidence for control. Methods Larva immersion method. Results The lab population was the most susceptive with LC50 of 0.001 3 mg/L to deltamethrin, 0.003 8 mg/L to beta -cypermethrin, 0.027 7 mg/L to permethrin, 0. 181 3 mg/L to esbiothrin,0. 018 3 mg/L to DDVP, 0.096 8 mg/L to propoxur and 0. 000 4 mg/L to temephos. The highest resistance ratio of insecticide was 200 in Nanjing, Xuzhou, Lianyungang and Wuxi. Conclusion In Jiangsu Province C. pipens pallens have developed different resistance to DDVP, temephos, deltamethrin, beta - cypermethrin and propoxur. It is necessary to use the result of survey to prevent the resistance from developing.%目的 为了解江苏省淡色库蚊幼虫对卫生杀虫剂的敏感性和抗药性发生发展状况进行生物学抗性调查.方法 幼虫浸渍法.结果 实验室淡色库蚊幼虫对溴氰菊酯、高效氯氰菊酯、氯菊酯、生物丙烯菊酯、敌敌畏、残杀威和双硫磷幼虫敏感性LC50分别为0.001 3、0.003 8、0.027 7,0.181 3、0.018 3、0.096 8、0.000 4 mg/L.南京、徐州、连云港和无锡等地蚊虫幼虫抗性分别是敏感品系的数倍到200倍不等.结论 江苏省淡色库蚊幼虫对敌敌畏、双硫磷、溴氰菊酯、高效氯氰菊酯和残杀威等杀虫剂均产生不同程度的抗性.抗性调查的结果为指导江苏省蚊虫防治以及合理使用卫生杀虫剂提供科学依据.
Purification and partial characterization of glutathione S-transferase from insecticide-resistant field populations of Liposcelis paeta Pearman (Psocoptera: Liposcelididae).
Wu, Shuang; Dou, Wei; Wu, Jing-Jing; Wang, Jin-Jun
Enzymes that possess glutathione S-transferase (GST) activity were purified to homogeneity by glutathione-agarose affinity chromatography from three field populations of Liposcelis paeta (Pearman). These populations were collected from Nanyang city of Henan Province (NY), Wuzhou (WZ) and Hezhou (HZ) cities of Guangxi Province, China, and had different susceptibilities to dichlorvos [LC(50)s of the NY (281.48 mg/m(2)), the WZ (285.07 mg/m(2)), and the HZ (243.52 mg/m(2)), respectively]. The specific activities of purified enzymes from these three populations increased 32.24-, 99.81-, and 42.52-fold, respectively. Kinetic analyses showed that the catalytic activity of purified GST from NY population towards GSH was much higher than the others, while WZ population reached the highest in V(max) (CDNB). SDS-polyacrylamide electrophoresis revealed that the purified GST had two subunits with a molecular mass of 23.31 and 20.43 kDa for NY, 53.14 and 20.13 kDa for WZ, and 50.79 and 19.42 kDa for HZ, respectively. The in vitro inhibition studies of GSTs indicated that three kinds of insecticides (chlorpyrifos, carbosulfan, and cypermethrin) and five metallic ions (Zn(2+), Ba(2+), Ca(2+), Hg(2+), Mn(2+), and Mg(2+)) all possessed inhibitory effects on purified GST, and ethacrynic acid (EA, a specific inhibitor of GST) expressed inhibitory effects. In the bioassay, three populations of L. paeta had different susceptibilities to different insecticides, even after they were reared on diets consisting of 25% EA. The GST activities of L. paeta from different areas also showed different temperature and pH stabilities. The differences in GST among the three populations may be attributed partially to the differences in control practices for psocids between Henan and Guangxi Provinces. (c) 2009 Wiley Periodicals, Inc.
Declining ring-necked pheasants in the Klamath Basin, California: I. Insecticide exposure
Grove, Robert A.; Buhler, D.R.; Henny, Charles J.; Drew, A.D.
A study of organophosphorus (OP) insecticide exposure was conducted on a declining population of ring-necked pheasants (Phasianus colchicus) associated with agricultural lands at Tule Lake National Wildlife Refuge (TLNWR) during the summers of 1990a??92. Findings at TLNWR were compared with a nearby pheasant population at Lower Klamath National Wildlife Refuge (LKNWR) not subjected to intensive farming or OP insecticide applications. Direct toxicity of anticholinesterase (antiChE) compounds (in this case methamidophos) killed 2 young pheasants (91 and 92% brain acetylcholinesterase [AChE] inhibition), but no deaths of adult radio-equipped hens were ascribed to direct insecticide intoxication. However, within 20 days postspray of OP insecticides, 68% (28 of 41) of the adult pheasants collected at TLNWR were exposed to antiChE insecticides, and exhibited brain AChE inhibition of 19a??62%, with 15% (6 of 41) showing >55% brain AChE inhibition. The lack of radio-equipped hens dying was unexpected because >50% brain AChE inhibition has been frequently used as a diagnostic tool for evaluating cause of death from antiChE insecticides. No young were radio-equipped, so the extent of the effects of insecticide exposure on the survivorship of young was unknown. It is concluded that insecticide exposure was not the major factor impacting the pheasant population (see Grove et al., in press), although some young were acutely intoxicated. However, the loss of insects killed by insecticide use may have contributed to food shortages of young pheasants, indirectly influencing survival.
Insect P450 inhibitors and insecticides: challenges and opportunities.
Feyereisen, René
P450 enzymes are encoded by a large number of genes in insects, often over a hundred. They play important roles in insecticide metabolism and resistance, and growing numbers of P450 enzymes are now known to catalyse important physiological reactions, such as hormone metabolism or cuticular hydrocarbon synthesis. Ways to inhibit P450 enzymes specifically or less specifically are well understood, as P450 inhibitors are found as drugs, as fungicides, as plant growth regulators and as insecticide synergists. Yet there are no P450 inhibitors as insecticides on the market. As new modes of action are constantly needed to support insecticide resistance management, P450 inhibitors should be considered because of their high potential for insect selectivity, their well-known mechanisms of action and the increasing ease of rational design and testing.
陕西省白纹伊蚊抗药性研究和防制策略%Insecticide resistance of Aedes albopictus in Shaanxi province,China and its control strategy
Institute of Scientific and Technical Information of China (English)
孙养信; 吕文; 霍丽霞; 周以军; 王博
目的 了解陕西省伊蚊分布地区铜川及安康市白纹伊蚊抗药性情况.方法 采用区分剂量法测定白纹伊蚊幼虫对3种杀虫剂的24 h死亡率;采用半数致死剂量(LC50)法测定白纹伊蚊幼虫对9种杀虫剂的LC50.结果 区分剂量法测定结果显示,铜川和安康地区白纹伊蚊对敌敌畏、氯菊酯、溴氰菊酯均为抗性群体;半数致死量法测定结果显示,安康、铜川市白纹伊蚊对高效氯氰菊酯的LC50分别为0.003 71和0.001 45 mg/L;对氯菊酯的LC50分别为0.006 25和0.017 67 mg/L;对溴氰菊酯的LC50分别为0.002 69和0.000 76 mg/L;对氯氰菊酯的LC50分别为0.017 46和0.009 37 mg/L;对DDT的LC50分别为0.809 54和0.217 06 mg/L;对敌敌畏的LC50分别为0.040 15和0.026 77 mg/L;对双硫磷的LC50分别为0.002 22和0.003 10 mg/L;对残杀威的LC50分别为0.348 14和0.651 91 mg/L;对仲丁威的LC50分别为0.157 19和0.543 77 mg/L;抗性倍数以敌敌畏、双硫磷、残杀威等较高.结论 在应用杀虫剂防治媒介伊蚊时,应结合地理区域及生态环境特点对蚊虫进行综合治理,科学合理地使用杀虫剂,以减缓抗药性的产生.%Objective To evaluate the insecticide resistance of Aedes albopictus in Tongchuan city and Ankang city of Shaanxi province, China. Methods Distinguishing dosage method was used to measure the mortality rates of Ae. Albopictus larvae within 24 h of exposure to three insecticides; median lethal dose (LC50) method was used to measure the LC50 of nine insecticides for Ae. Albopictus larvae. Results The distinguishing dosage method showed that Ae. Albopictus in Ankang and Tongchuan had resistances to dichlorvos, permethrin, and deltamethrin. The LC50 method showed that for Ae. Albopictus in Ankang and Tongchuan, the LC50 of (5-cypermethrin was 0.003 71 mg/L and 0.001 45 mg/L, the LC50 of permethrin was 0.006 25 mg/L and 0.017 67 mg/L, the LC50 of deltamethrin was 0.002 69 mg/L and 0.000 76 mg/L, the LC50 of
Flavanone glycosides as acetylcholinesterase inhibitors: Computational and experimental evidence
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C Remya
Full Text Available Acetylcholinesterase hydrolyzes the neurotransmitter called acetylcholine and is crucially involved in the regulation of neurotransmission. One of the observable facts in the neurodegenerative disorders like Alzheimer′s disease is the decrease in the level of acetylcholine. Available drugs that are used for the treatment of Alzheimer′s disease are primarily acetylcholinesterase inhibitors with multiple activities. They maintain the level of acetylcholine in the brain by inhibiting the acetylcholinesterase function. Hence acetylcholinesterase inhibitors can be used as lead compounds for the development of drugs against AD. In the present study, the binding potential of four flavanone glycosides such as naringin, hesperidin, poncirin and sakuranin against acetylcholinesterase was analysed by using the method of molecular modeling and docking. The activity of the top scored compound, naringin was further investigated by enzyme inhibition studies and its inhibitory concentration (IC 50 towards acetylcholinesterase was also determined.
Acetylcholinesterase Inhibitory Activities of Flavonoids from the Leaves of Ginkgo biloba against Brown Planthopper
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Xiao Ding
Full Text Available Ginkgo biloba is a traditional Chinese medicinal plant which has potent insecticidal activity against brown planthopper. The MeOH extract was tested in the acetylcholinesterase (AChE inhibitory assay with IC50 values of 252.1 μg/mL. Two ginkgolides and thirteen flavonoids were isolated from the leaves of Ginkgo biloba. Their structures were established on the basis of spectroscopic data interpretation. It revealed that the 13 isolated flavonoids were found to inhibit AChE with IC50 values ranging from 57.8 to 133.1 μg/mL in the inhibitory assay. AChE was inhibited dose dependently by all tested flavonoids, and compound 6 displayed the highest inhibitory effect against AChE with IC50 values of 57.8 μg/mL.
Acetylcholinesterase inhibition by flavonoids from Agrimonia pilosa.
Jung, Mankil; Park, Moonso
In a bioassay-guided search for acetylcholinesterase (AChE) inhibitors from 180 medicinal plants, an ethyl acetate extract of whole plants of Agrimonia pilosa ledeb yielded tiliroside (1), 3-methoxy quercetin (2), quercitrin (3) and quercetin (4). We report herein for the first time that all four flavonol compounds showed significant inhibitory effects on AChE, particularly quercetin (4), which showed twice the activity of dehydroevodiamine (DHED).
Acetylcholinesterase Inhibition by Flavonoids from Agrimonia pilosa
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Moonso Park
Full Text Available In a bioassay-guided search for acetylcholinesterase (AChE inhibitors from 180 medicinal plants, an ethyl acetate extract of whole plants of Agrimonia pilosa ledeb yielded tiliroside (1, 3-methoxy quercetin (2, quercitrin (3 and quercetin (4. We report herein for the first time that all four flavonol compounds showed significant inhibitory effects on AChE, particularly quercetin (4, which showed twice the activity of dehydroevodiamine (DHED.
Molecular Probe Analysis of Mammalian Brain Acetylcholinesterase
Project and Degrees Awarded During this Reporting Period: Judith K. Marquis, Principal Investigator Thomas Biagioni , Senior Research Technician Robert...binding sites in nerve membrane vesicles. Comp. Biochem. Physiol. 80C: 203-205 (1985). 5. Volpe, L.S., T.M. Biagioni & J.K. Marquis: In vitro modulation of...Saxena, Vol. 6(1988Y.8 11. Marquis, J.K. & T.M. Biagioni : Selective inhibition of acetylcholinesterase and butyrylcholinesterase in human plasma
Moving From the Old to the New: Insecticide Research on Bed Bugs since the Resurgence
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Alvaro Romero
Full Text Available The scarcity of bed bugs in many countries over the last 50 years has resulted in a lack of modern research into the toxicology of this pest. Although bed bugs resurged in the late 1990s, published research related to insecticides has lagged behind and only began to appear in 2006. The difficulty in controlling bed bugs triggered the interest of both private and academic sectors to determine the value of currently available insecticides. What follows, is updated information on effectiveness of products, studies on insecticide susceptibility, identification of mechanisms of insecticide resistance and chemical strategies proposed to overcome resistance in modern bed bug populations.
Modeling the integration of parasitoid, insecticide, and transgenic insecticidal crop for the long-term control of an insect pest.
Onstad, David W; Liu, Xiaoxia; Chen, Mao; Roush, Rick; Shelton, Anthony M
The tools of insect pest management include host plant resistance, biological control, and insecticides and how they are integrated will influence the durability of each. We created a detailed model of the population dynamics and population genetics of the diamondback moth, Plutella xylostella L., and its parasitoid, Diadegma insulare (Cresson), to study long-term pest management in broccoli Brassica oleracea L. Given this pest's history of evolving resistance to various toxins, we also evaluated the evolution of resistance to transgenic insecticidal Bt broccoli (expressing Cry1Ac) and two types of insecticides. Simulations demonstrated that parasitism provided the most reliable, long-term control of P. xylostella populations. Use of Bt broccoli with a 10% insecticide-free refuge did not reduce the long-term contribution of parasitism to pest control. Small refuges within Bt broccoli fields can delay evolution of resistance > 30 generations if resistance alleles are rare in the pest population. However, the effectiveness of these refuges can be compromised by insecticide use. Rainfall mortality during the pest's egg and neonate stages significantly influences pest control but especially resistance management. Our model results support the idea that Bt crops and biological control can be integrated in integrated pest management and actually synergistically support each other. However, the planting and maintenance of toxin-free refuges are critical to this integration.
Acceptability and perceived side effects of insecticide indoor residual spraying under different resistance management strategies Aceptabilidad y efectos secundarios percibidos del rociado residual intradomiciliario de insecticidas bajo diferentes esquemas de manejo de resistencia
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Américo David Rodríguez
Full Text Available OBJECTIVE: To assess household acceptability and perceived side effects of residual indoor pyrethroid (PYR, carbamate and organophosphate insecticides sprayed by annual rotation (ROT, spatial mosaic (MOS, and a single insecticide (DDT or PYR in communities of the coastal plain of Chiapas, Mexico. MATERIAL AND METHODS: A questionnaire to assess the acceptability and perceived side effects of indoor insecticides was administered to one member of 30% of the families in eight villages of Chiapas. The association of different insecticide treatments with their responses was evaluated (Chi-square. The intensity of side effects indicated under different treatments was compared in an ordered logistic model, using a severity index as the response variable. RESULTS: Insecticide spraying as a probable cause of symptoms was identified by 2.1% of interviewees. A significantly high percentage of persons with blurred vision, dizziness, sneezing, coughing, numbness, watery eyes, and itching lived in villages under MOS and ROT and a high severity index was significantly associated with ROT treatment. Reduction of mosquito bites and cockroaches were the perceived main benefits, and most villagers that perceived no benefits lived in DDT treated villages. Most of the interviewees welcomed spraying (83.7%, but the smell and having to remove furniture from houses were the main arguments against it. CONCLUSIONS: Acceptability correlated with insecticide spray coverage, although the most frequent suggestion for improvement was to increase the understanding of the objectives of spraying in the communities. The frequency of side effects was low, but higher in localities where a combination of insecticides was applied. This is a limitation for the use of this type of resistance management strategy in public health.OBJETIVO: Evaluar la aceptabilidad y los efectos secundarios del rociado intradomiciliar de insecticidas pyrethroides (PYR, carbamato y organophosphato rociados
An Indigenously Developed Insecticidal Aerosol
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R. N. Varma
Full Text Available A total of 6 "Test" insecticidal aerosols (TA-I to VI indigenously produced were tested during the years 1966-67 as suitable replacements for imported aerosols.TA-I produced deep yellow staining and a yellowish spray mist. Its capacity was only 120 ml fluid. TA-III types II and III containing modified aerosol formulation with "Esso solvent 3245" and mineral turpentine oil (Burmah Shelland Freon 12 11 (all indigenouswere comparable to he "SRA" in insecticidial efficacy. The container was also manufactured in the country and it compared well with the "SRA" in construction, resistance against rough usage and mechanical function. They were both finally approved for introduction in the services as replacement for imported aerosols. TA-IV performed well in inscticidial assessment, but the aerosols formulation. TA-V and VI were similar to TA-III types II and III respectively.
Mutagenic and cytotoxic activities of benfuracarb insecticide.
Eren, Yasin; Erdoğmuş, Sevim Feyza; Akyıl, Dilek; Özkara, Arzu
Benfuracarb is a carbamate insecticide used to control insect pests in vegetables and it has anti-acetylcholinesterase activity lower than other carbamates. Cytotoxic effects of benfuracarb were evaluated by using root growth inhibition (EC50), mitotic index (MI), and mitotic phase determinations on the root meristem cells of Allium cepa and mutagenic effects were determined in Salmonella typhymurium Ames test by TA98 and TA100 strains with and without metabolic activation. In Allium test, 1 % DMSO was used as negative control group and 10 ppm MMS was used as positive control group. 75 ppm concentration of benfuracarb was found as EC50. In MI and mitotic phases determination study, 37.5, 75 and 150 ppm doses of benfuracarb were used. Dose-dependent cytotoxic activity was found by root growth inhibition and MI studies. It was identified that mitotic inhibition activity of benfuracarb was higher than 10 ppm MMS. In Ames test, mutagenic activity was not observed and over 200 µg/plate of benfuracarb was determined as cytotoxic to S. typhymurium strains. Benfuracarb can be called as "mitotic inhibitor" but not called as mutagen.
Mutations in Acetylcholinesterase2 (ace2) increase the insensitivity of acetylcholinesterase to fosthiazate in the root-knot nematode Meloidogyne incognita.
Huang, Wen-Kun; Wu, Qin-Song; Peng, Huan; Kong, Ling-An; Liu, Shi-Ming; Yin, Hua-Qun; Cui, Ru-Qiang; Zhan, Li-Ping; Cui, Jiang-Kuan; Peng, De-Liang
The root-knot nematode Meloidogyne incognita causes severe damage to continuously cropping vegetables. The control of this nematode relies heavily on organophosphate nematicides in China. Here, we described resistance to the organophosphate nematicide fosthiazate in a greenhouse-collected resistant population (RP) and a laboratory susceptible population (SP) of M. incognita. Fosthiazate was 2.74-fold less toxic to nematodes from RP than that from SP. Quantitative real-time PCR revealed that the acetylcholinesterase2 (ace2) transcription level in the RP was significantly higher than that in the SP. Eighteen nonsynonymous amino acid differences in ace2 were observed between the cDNA fragments of the RP and SP. The acetylcholinesterase (AChE) protein activity in the RP was significantly reduced compared with that in the SP. After knocking down the ace2 gene, the ace2 transcription level was significantly decreased, but no negative impact on the infection of juveniles was observed. The 50% lethal concentration of the RNAi RP population decreased 40%, but the inhibition rate of fosthiazate against AChE activity was significantly increased in RP population. Thus, the increased fosthiazate insensitivity in the M. incognita resistant population was strongly associated with mutations in ace2. These results provide valuable insights into the resistance mechanism of root-knot nematode to organophosphate nematicides.
Detecting resistance to organophosphates and carbamates in the cattle tick Boophilus microplus, with a propoxur-based biochemical test.
Baxter, G D; Green, P; Stuttgen, M; Barker, S C
Rapid and sensitive detection of resistance to insecticides in arthropods is needed. In the cattle tick. Boophilus microplus, resistance to a variety of acaricides is widespread. The most commonly used assay for resistance, the larval packet test, takes at least two, but generally six weeks for a one-host tick like B. microplus to complete and may take up to three months to complete for three-host ticks. Here we describe a test for resistance to organophosphate acaricides that can be used on larvae and adult ticks which takes less than 24 hours. The test measures the difference in acetylcholinesterase (AChE) activity in homogenates of ticks in the presence and absence of propoxur, a carbamate acaricide. We found clear discrimination of organophosphate-susceptible and organophosphate-resistant adults with 100 microM propoxur. AChE from susceptible ticks had almost no activity at this concentration of propoxur whereas AChE from resistant ticks had 67% of its potential activity. AChE from heterozygote ticks could also be distinguished from AChE from homozygous-susceptible and homozygous-resistant ticks. This is the first biochemical test for resistance to an acaricide. Rapid, sensitive tests like ours will allow resistance to organophosphates to be detected soon after it develops in the field, thus, the spread of resistance might be slowed and the useful life of acaricides extended.
The resistance dynamics of Musca domestica to insecticides and the control strategies in the 26 years in Jinan city%济南市家蝇26年抗药性动态及防制对策
Institute of Scientific and Technical Information of China (English)
王永明; 刘慧媛; 王东; 彭文广; 辛正
Objective To investigate the resistance dynamics of Musca domestica in the 26 years in Jinan city for the development of its control strategies. Methods The micro - drop method was used for bioassay of M. domestuia collected in different years in different parts of the city to determine its resistance status and trends. Insecticides dissolved in acetone were applied topically on the thoracic notum of female adults. Results M. domestica in Jinan city and surrounding area in 1982 were susceptible to conventional pyrethrin chemicals. However, 26 years later, the susceptibility of M. domestica to conventional pyrethrin chemicals decreased to varying degrees. Compared with the susceptible strain, the resistance of field housefly to deltamethrn and to bata-cypermethrinwas was 75.00-211.67 and 25.52-116.21 folds in 2008 respectively, indicating that the degree of housefly resistance was at a medium or high level. Conclusion The resistance of M. domestica to pyrethrin chemicals in Jinan and the surrounding areas has developed to varying degrees. Strategies for the control of resistance should be developed based on the local conditions.%目的 了解济南市家蝇26年来抗药性的发展动态,探讨其防制对策.方法 采用微量点滴法,对不同年份采集的不同地区家蝇进行生物测定,以确定家蝇的抗药性状况及其发展趋势.结果 1982年济南市区及周边地区家蝇对常用菊酯类药剂均处于敏感阶段,26年后对菊酯类药剂敏感性均有不同程度的下降.2008年,济南市家蝇对溴氰菊酯的抗性为75.00~211.67倍,对高效氯氰菊酯的抗性为25.52~116.21倍,均已达到中、高度抗性.结论 济南市区及周边地区的家蝇对菊酯类药剂已产生不同程度的抗性,各县(市、区)应根据当地的具体情况制定防制对策.
江苏省部分地区德国小蠊对常用杀虫剂的抗药性调查%Resistance of Blattella germanica to common used insecticides in some areas in Jiangsu Province
Institute of Scientific and Technical Information of China (English)
刘慧; 张爱军; 杨维芳; 褚宏亮; 孙俊
目的 了解江苏省部分地区德国小蠊对溴氰菊酯、高效氯氰菊酯、敌敌畏、残杀威、乙酰甲胺磷5种常用杀虫剂的抗药性程度,以便通过抗性程度来指导科学、合理的用药.方法 药膜接触法.结果 江苏省4个地市的德国小蠊野外品系对上述5种杀虫剂的平均抗性系数分别为17.0、8.4、3.2、1.6和4.4.南京、南通、淮安品系对溴氰菊酯的抗性倍数最高,分别为22.9、20.6、16.1;丹阳品系对高效氯氰菊酯的抗性程度最高(R=10.9).各品系德国小蠊对残杀威的抗性程度较低(R=1.6).结论 江苏地区4个野外品系德国小蠊对溴氰菊酯、高效氯氰菊酯、敌敌畏和乙酰甲胺磷均产生不同程度的抗性.%Objective To estimate the susceptibility or resistance of Blattella germanica, including normal strain and four field-collected strain to deltamethrin, beta-cypermethrin, dichlorvos, propoxur and acephate in some areas in Jiangsu Province. Methods Contacting with chemical cover. Results The average resistance ratios of field-collected strains to deltamethrin, beta-cypermethrin, dichlorvos, propoxur and acephate were 17.0, 8.4, 3.2, 1.6 and 4.4 respectively. The resistance ratios of deltamethrin were high in Nanjing, Nantong and Huaian four tield - collected strain( R = 22. 9 , 20. 6 , 16.1). The resistance also reached the high level to beta - cypermethrin in Danyang strain ( R = 10. 9) . The average resistance ratios of field - collected strains to propoxur was low ( R = 1. 6). Conclusion Field collected strains of Blattella germanica in Jiangsu Province have already developed different resistance to four kinds of insecticides.
Efficacy of PermaNet® 2.0 and PermaNet® 3.0 against insecticide-resistant Anopheles gambiae in experimental huts in Côte d'Ivoire
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Koffi Alphonsine A
Full Text Available Abstract Background Pyrethroid resistance in vectors could limit the efficacy of long-lasting insecticidal nets (LLINs because all LLINs are currently treated with pyrethroids. The goal of this study was to evaluate the efficacy and wash resistance of PermaNet® 3.0 compared to PermaNet® 2.0 in an area of high pyrethroid in Côte d'Ivoire. PermaNet® 3.0 is impregnated with deltamethrin at 85 mg/m2 on the sides of the net and with deltamethrin and piperonyl butoxide on the roof. PermaNet® 2.0 is impregnated with deltamethrin at 55 mg/m2 across the entire net. Methods The study was conducted in the station of Yaokoffikro, in central Côte d'Ivoire. The efficacy of intact unwashed and washed LLINs was compared over a 12-week period with a conventionally-treated net (CTN washed to just before exhaustion. WHO cone bioassays were performed on sub-sections of the nets, using wild-resistant An. gambiae and Kisumu strains. Mosquitoes were collected five days per week and were identified to genus and species level and classified as dead or alive, then unfed or blood-fed. Results Mortality rates of over 80% from cone bioassays with wild-caught pyrethroid-resistant An. gambiae s.s were recorded only with unwashed PermaNet® 3.0. Over 12 weeks, a total of 7,291 mosquitoes were collected. There were significantly more An. gambiae s.s. and Culex spp. caught in control huts than with other treatments (P An. gambiae s.s and Culex spp, were lower for the control than for other treatments (P 0.05 except for unwashed PermaNet® 3.0 (P Conclusions This study showed that unwashed PermaNet® 3.0 caused significantly higher mortality against pyrethroid resistant An. gambiae s.s and Culex spp than PermaNet® 2.0 and the CTN. The increased efficacy with unwashed PermaNet® 3.0 over PermaNet® 2.0 and the CTN was also demonstrated by higher KD and mortality rates (KD > 95% and mortality rate > 80% in cone bioassays performed with wild pyrethroid-resistant An. gambiae s
Acetylcholinesterase Inhibitory and Antioxidant Properties of Euphorbiacharacias Latex
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Francesca Pintus
Full Text Available The aim of the present study was to evaluate the acetylcholinesterase inhibitory capacity and the antioxidant properties of extracts of Euphorbia characias latex, a Mediterranean shrub. We performed a new extraction method involving the use of the trichloroacetic acid. The extract showed high antioxidant activity, was rich in total polyphenolic and flavonoid content and exhibited substantial inhibition of acetylcholinesterase activity.
Current Perspectives on Plague Vector Control in Madagascar: Susceptibility Status of Xenopsylla cheopis to 12 Insecticides.
Miarinjara, Adélaïde; Boyer, Sébastien
Plague is a rodent disease transmissible to humans by infected flea bites, and Madagascar is one of the countries with the highest plague incidence in the world. This study reports the susceptibility of the main plague vector Xenopsylla cheopis to 12 different insecticides belonging to 4 insecticide families (carbamates, organophosphates, pyrethroids and organochlorines). Eight populations from different geographical regions of Madagascar previously resistant to deltamethrin were tested with a World Health Organization standard bioassay. Insecticide susceptibility varied amongst populations, but all of them were resistant to six insecticides belonging to pyrethroid and carbamate insecticides (alphacypermethrin, lambdacyhalothrin, etofenprox, deltamethrin, bendiocarb and propoxur). Only one insecticide (dieldrin) was an efficient pulicide for all flea populations. Cross resistances were suspected. This study proposes at least three alternative insecticides (malathion, fenitrothion and cyfluthrin) to replace deltamethrin during plague epidemic responses, but the most efficient insecticide may be different for each population studied. We highlight the importance of continuous insecticide susceptibility surveillance in the areas of high plague risk in Madagascar.
Current Perspectives on Plague Vector Control in Madagascar: Susceptibility Status of Xenopsylla cheopis to 12 Insecticides.
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Adélaïde Miarinjara
Full Text Available Plague is a rodent disease transmissible to humans by infected flea bites, and Madagascar is one of the countries with the highest plague incidence in the world. This study reports the susceptibility of the main plague vector Xenopsylla cheopis to 12 different insecticides belonging to 4 insecticide families (carbamates, organophosphates, pyrethroids and organochlorines. Eight populations from different geographical regions of Madagascar previously resistant to deltamethrin were tested with a World Health Organization standard bioassay. Insecticide susceptibility varied amongst populations, but all of them were resistant to six insecticides belonging to pyrethroid and carbamate insecticides (alphacypermethrin, lambdacyhalothrin, etofenprox, deltamethrin, bendiocarb and propoxur. Only one insecticide (dieldrin was an efficient pulicide for all flea populations. Cross resistances were suspected. This study proposes at least three alternative insecticides (malathion, fenitrothion and cyfluthrin to replace deltamethrin during plague epidemic responses, but the most efficient insecticide may be different for each population studied. We highlight the importance of continuous insecticide susceptibility surveillance in the areas of high plague risk in Madagascar.
Current Perspectives on Plague Vector Control in Madagascar: Susceptibility Status of Xenopsylla cheopis to 12 Insecticides
Miarinjara, Adélaïde; Boyer, Sébastien
Plague is a rodent disease transmissible to humans by infected flea bites, and Madagascar is one of the countries with the highest plague incidence in the world. This study reports the susceptibility of the main plague vector Xenopsylla cheopis to 12 different insecticides belonging to 4 insecticide families (carbamates, organophosphates, pyrethroids and organochlorines). Eight populations from different geographical regions of Madagascar previously resistant to deltamethrin were tested with a World Health Organization standard bioassay. Insecticide susceptibility varied amongst populations, but all of them were resistant to six insecticides belonging to pyrethroid and carbamate insecticides (alphacypermethrin, lambdacyhalothrin, etofenprox, deltamethrin, bendiocarb and propoxur). Only one insecticide (dieldrin) was an efficient pulicide for all flea populations. Cross resistances were suspected. This study proposes at least three alternative insecticides (malathion, fenitrothion and cyfluthrin) to replace deltamethrin during plague epidemic responses, but the most efficient insecticide may be different for each population studied. We highlight the importance of continuous insecticide susceptibility surveillance in the areas of high plague risk in Madagascar. PMID:26844772
A comparison of Drosophila melanogaster detoxification gene induction responses for six insecticides, caffeine and phenobarbital.
Willoughby, Lee; Chung, Henry; Lumb, Chris; Robin, Charles; Batterham, Philip; Daborn, Phillip J
Modifications of metabolic pathways are important in insecticide resistance evolution. Mutations leading to changes in expression levels or substrate specificities of cytochrome P450 (P450), glutathione-S-transferase (GST) and esterase genes have been linked to many cases of resistance with the responsible enzyme shown to utilize the insecticide as a substrate. Many studies show that the substrates of enzymes are capable of inducing the expression of those enzymes. We investigated if this was the case for insecticides and the enzymes responsible for their metabolism. The induction responses for P450s, GSTs and esterases to six different insecticides were investigated using a custom designed microarray in Drosophila melanogaster. Even though these gene families can all contribute to insecticide resistance, their induction responses when exposed to insecticides are minimal. The insecticides spinosad, diazinon, nitenpyram, lufenuron and dicyclanil did not induce any P450, GST or esterase gene expression after a short exposure to high lethal concentrations of insecticide. DDT elicited the low-level induction of one GST and one P450. These results are in contrast to induction responses we observed for the natural plant compound caffeine and the barbituate drug phenobarbital, both of which highly induced a number of P450 and GST genes under the same short exposure regime. Our results indicate that, under the insecticide exposure conditions we used, constitutive over-expression of metabolic genes play more of a role in insect survival than induction of members of these gene families.
Determination of Plutella xylostella(L.)Resistance to Nine Insecticides in Central China%华中地区小菜蛾对9种杀虫剂的抗药性测定
Institute of Scientific and Technical Information of China (English)
夏耀民; 鲁艳辉; 朱勋; 申君; 游红; 李建洪
采用室内浸叶法,测定了华中地区5个蔬菜产区(河南洛阳白马寺镇、湖南岳阳广兴洲镇、湖北武穴梅川镇、湖北宜昌当阳市、湖北云梦隔蒲镇)田间小菜蛾种群对2%阿维菌素乳油(EC)、16000 IU·mg-1 Bt工程菌WG-001可湿性粉剂(WP)、20%高效氯氰菊酯EC、5%氯虫苯甲酰胺EC、2.5%多杀菌素悬浮剂(SC)、10%溴虫腈EC、5%氟啶脲EC、20%丁醚脲EC、5%茚虫威EC等9种常用杀虫剂的抗药性。结果表明:5个小菜蛾种群对阿维菌素(抗药性倍数为44.5~92.0倍)、Bt(抗药性倍数为66.5~202.1倍)、高效氯氰菊酯(抗药性倍数为76.2~146.4倍)已产生了高水平至极高水平抗性,对氟啶脲(抗药性倍数为32.5~82.5倍)的抗药性达到中等至高水平抗性,对多杀菌素(抗药性倍数为6.5~19.4倍)、氯虫苯甲酰胺(抗药性倍数为3.1~23.1倍)、溴虫腈(抗药性倍数为2.6~22.3倍)和茚虫威(抗药性倍数为7.1~26.3倍)表现为中等及以下水平抗性,对丁醚脲(抗药性倍数为2.3~7.7倍)表现为敏感至低水平抗性。因此,华中地区的小菜蛾防治应注重氯虫苯甲酰胺、溴虫腈、丁醚脲与多杀菌素、茚虫威、氟啶脲交替、轮换使用,以便延缓抗药性的产生与发展,取得更好的防效。%Five field populations of diamondback moth,Plutella xylostella,including Luoyang in Henan Province,Yueyang in Hunan Province,and Wuxue,Yunmeng and Yichang in Hubei Province, were collected from the central China.P. xylostella populations had resistance to 9 insecticides as 2%abamectin EC,16 000 IU·mg-1 Bt WG-001 WP,20%beta-cypermethrin EC,5%chlorantraniliprole EC,2.5% spinosad SC,10% chlorfenapyr EC,5% chlorfluazuron EC,20% diafenthiuron EC,5%indoxacarb EC.The bioassay results indicated that 5 populations exhibited high to extreme high level of resistance to abamectin,Bt,beta-cypermethrin,with the resistance ratio 44
Improving Selection of Insecticide Resistance to Acetamiprid in the Parasitiod Tetrastichus brontispae and Asecodes hispinarum,by Integrating Brontispa longissima%抗啶虫脒椰心叶甲种群对椰甲截脉姬小峰和椰心叶甲啮小蜂抗药性选育的影响
Institute of Scientific and Technical Information of China (English)
金涛; 金启安; 林玉英; 温海波; 彭正强
筛选椰心叶甲对啶虫脒的抗药性,并以筛选后的椰心叶甲作为椰甲截脉姬小峰和椰心叶甲啮小蜂的寄主,观察这两种寄生蜂后代种群的抗性水平变化情况.结果表明,经筛选后,椰心叶甲的抗性水平增长了1.33倍,椰甲截脉姬小峰和椰心叶甲啮小蜂的抗性倍数分别增长了2.3倍和2.73倍,且椰心叶甲及其寄生蜂的后代种群抗性个体频率均显著高于初始种群.表明可利用椰心叶甲的抗药性来促进椰甲截脉姬小峰和椰心叶甲啮小蜂的抗性选育.%The insecticide resistance of Brontispa longissima to acetamiprid was studied, and the insecticide resistance of Tetrastichus brontispae and Asecodes hispinarum was investigated after using the population of B. longissima as the host for rearing offspring population of these two parasitoid wasps. The results showed that resistance level of B. longissima was only increased 1.33 times, and resistance ratio of T. brontispae and A. hispinarum was increased 2.3 and 2.73 times, respectively. But resistant individual frequency in the populations of B. longissima and its parasitic wasps were significantly higher than in their original populations. It proved that using insecticide resistance of B. longissima could promote resistance selection of T. brontispae and A. hispinarum.
抗吡虫啉棉蚜对其他新烟碱类药剂的交互抗性及相关酶的活性变化%Cross-resistance of the imidacloprid-resistant population of Aphis gossypii Glover (Homoptera: Aphididae ) to other neonicotinoid insecticides and changes in activities of related enzymes
Institute of Scientific and Technical Information of China (English)
史晓斌; 石绪根; 王红艳; 夏晓明; 王开运
In order to clarify the cross-resistance and the change in related enzymes of the imidacloprid-resistant population of Aphis gossypii to other neonicotinoid insecticides, the bioassay method was used to determine the cross-resistance of different resistant populations of imidacloprid-resistant A. Gossypii to dinotefuran and nitenpyram, and the synergism of three detoxification enzyme inhibitors to imidacloprid and other two neonicotinoid insecticides using cotton aphids of the imidacloprid-resistant population selected in the laboratory, the Xiajin resistant population in the field in Shandong and the susceptible population. The activities of detoxification enzymes and AChE of three populations of cotton aphid and the inhibition effect of insecticides were determined through biochemical analysis. The results showed that the imidacloprid-resistant population and the Xiajin resistant population exhibited no cross-resistance to dinotefuran, but showed 5. 28-fold and 4. 89-fold cross-resistance to nitenpyram, respectively. Dinotefuran could significantly inhibit the activities of CarE, GST and AChE of the imidacloprid-resistant cotton aphid. Nitenpyram showed little effect on the activities of CarE, GST and AChE of the imidacloprid-resistant cotton aphid. Carboxylesterase inhibitor TPP and mixed-functional oxidase inhibitor PBO had obvious synergism to imidacloprid and nitenpyram, while had little synergism to dinotefuran. Glutathione-S-transferase inhibitor DEM showed no obvious synergism to the three insecticides. Dinotefuran and nitenpyram could inhibit the activities of detoxification enzymes and AChE of the imidacloprid-resistant conton aphid, with dinotefuran showing significant effect. The results demonstrate the great application value of dinotefuran in control of the imidacloprid-resistant cotton aphid, and its structure can provide a reference to the development of neonicotinoid insecticides in the future.%为明确抗吡虫啉棉蚜Aphis gossypii对其他�
Knockdown and lethal effects of eight commercial nonconventional and two pyrethroid insecticides against moderately permethrin-resistant adult bed bugs, Cimex lectularius (L.) (Hemiptera: Cimicidae)
The common bed bug, Cimex lectularius (L.) (Hemiptera: Cimicidae) is undergoing a rapid resurgence in the United States during the last decade which has created a notable pest management challenge largely because the pest has developed resistance against DDT, organophosphates, carbamates, and pyreth...
Ion channels: molecular targets of neuroactive insecticides.
Raymond-Delpech, Valérie; Matsuda, Kazuhiko; Sattelle, Benedict M; Rauh, James J; Sattelle, David B
Many of the insecticides in current use act on molecular targets in the insect nervous system. Recently, our understanding of these targets has improved as a result of the complete sequencing of an insect genome, i.e., Drosophila melanogaster. Here we examine the recent work, drawing on genetics, genomics and physiology, which has provided evidence that specific receptors and ion channels are targeted by distinct chemical classes of insect control agents. The examples discussed include, sodium channels (pyrethroids, p,p'-dichlorodiphenyl-trichloroethane (DDT), dihydropyrazoles and oxadiazines); nicotinic acetylcholine receptors (cartap, spinosad, imidacloprid and related nitromethylenes/nitroguanidines); gamma-aminobutyric acid (GABA) receptors (cyclodienes, gamma-BHC and fipronil) and L-glutamate receptors (avermectins). Finally, we have examined the molecular basis of resistance to these molecules, which in some cases involves mutations in the molecular target, and we also consider the future impact of molecular genetic technologies in our understanding of the actions of neuroactive insecticides.
Global Trends in the Use of Insecticides to Control Vector-Borne Diseases
Berg, van den H.; Zaim, M.; Yadav, R.S.; Soares, A.; Ameneshewa, B.; Mnzava, A.; Hii, J.; Dash, A.P.; Ejov, M.
Background: Data on insecticide use for vector control are essential for guiding pesticide management systems on judicious and appropriate use, resistance management, and reduction of risks to human health and the environment. Objective: We studied the global use and trends of insecticide use for co
Multiple insecticide resistances and kdr mutation of Culex pipiens pallens in north-central Anhui Province%安徽省中北部淡色库蚊对多种杀虫剂抗性及其kdr基因突变研究
Institute of Scientific and Technical Information of China (English)
魏星; 杨小迪; 王小莉; 李江艳; 王媛媛; 夏惠; 常雪莲; 方强
Objective To understand the status of resistance to multiple insecticides and the frequencies of kdr mutations in Culex pipiens pallens from north⁃central Anhui Province. Methods From July to September,2014,the C. pipiens pallens mosquito larvae were collected in Huaibei,Bengbu and Chuzhou cities of the north⁃central Anhui Province and reared to adults. The female adult mosquitoes at 3-5 days post emergence were tested for susceptibility to the four insecticides,namely 0.05%deltamethrin,5%malathion,0.1%bendiocarb and 4%DDT,by using the standard WHO resistance tube bioassay. The detec⁃tion of the point mutations of the kdr gene at codon 1014 was conducted by PCR and DNA sequencing in the deltamethrin⁃resis⁃tant and⁃susceptible mosquitoes. Results High levels of resistance to all the four insecticides were found in all the three tested populations,although mosquito mortality varied among populations and test insecticides. Among the test insecticides,DDT showed lowest mortality with no significant difference(F=1.027,P>0.05)in all test populations,whereas significantly differ⁃ent mortalities were observed among populations for the remained three insecticides tested(deltamethrin,malathion,and ben⁃diocarb)(F = 23.823,33.955,128.841;all P 0.05);但接触溴氰菊酯、马拉硫磷、噁虫威后的死亡率差异均有统计学意义(F=23.823、33.955、128.841,P均<0.01)。3地淡色库蚊种群的kdr基因1014位点均存在L1014F、L1014S这2种非同义突变;L1014F突变频率与溴氰菊酯抗性水平呈正相关(r2=0.718,P<0.01)。结论安徽省中北部地区淡色库蚊对溴氰菊酯、马拉硫磷、噁虫威、DDT均产生了较强的抗性,kdr基因L1014F突变频率与溴氰菊酯抗性水平呈正相关;各地区卫生部门需加强对媒介蚊虫抗性的动态监测。
Study on Resistance of German Cockroach in Naval Vessels to Three Insecticides%舰艇上德国小蠊对3种杀虫剂的敏感性研究
Institute of Scientific and Technical Information of China (English)
林永丽; 曹敏; 郝蕙玲; 孙锦程
目的:研究大连 (Rp)、上海(Rc)、湛江(Rz)3地海军舰艇上的德国小蠊对溴 氰菊酯、高效氯氰菊酯和残杀威的敏感性。方法:药膜接触法。结果:Rp、Rc、Rz对溴氰菊 酯的平均抗性系数分别为1.84、1.75、1.92;对高效氯氰菊酯的平均抗性系数 分别为2.44、2.82、1.15;对残杀威的平均抗性系数分别为0.89、1. 27、1.36。结论:3个品系德国小蠊对3种杀虫剂均产生不同 程度的耐药性。%Objective:To study the susceptibility or resistance of German cockroach, including three field-collected strains in naval vessels fr om Dalian(Rp), Shanghai(Rc) and Zhanjiang(Rz) to cypermethrin,deltamethrin a nd propoxur. Methods:The method of contact with chemical cover was used in this study. Result:The average resistanc e ratioes of field-collected strains to cypermethrin were 1.84,1.75,1.92 respec tively; those of field-collected strains to deltamethrin were 2.44,2.82,1.15 res pectively; those of field-collected strains to propoxur were 0.89,1.27,1.36 resp ectively. Conclusion:Three strains of German cockroach hav e already developed varied low resistance to the three kinds of insecticides.
Population dynamics and insecticide resistance of Plutella xylostella in Inner Mongolia%内蒙古小菜蛾种群数量动态及抗药性监测
Institute of Scientific and Technical Information of China (English)
周晓榕; 常静; 庞保平; 吴青君; 张友军
2009-2011年对内蒙古呼和浩特市郊区十字花科蔬菜和武川县油菜上小菜蛾Plutella xylostella(L.)种群消长动态进行了调查,并比较了呼和浩特地区小菜蛾对11种杀虫剂的抗药性.结果表明,在呼和浩特郊区,小菜蛾成虫于4月上旬开始出现,一年中有4个发生高峰,分别为4月下旬或5月上旬、6月中旬、8月下旬和10月上旬;小菜蛾幼虫在春甘蓝和秋白菜整个生长期间均有发生,大约有4个发生高峰,分别为6月上中旬、6月下旬或7月上旬、9月上旬和10月上旬.在武川县,小菜蛾成虫于4月末或5月初开始发生,春夏季数量高于秋季,共有2个发生高峰,2009年为5月下旬和6月中旬,2010年为6月上旬和8月上中旬;小菜蛾幼虫在6月下旬开始出现,在油菜整个生长期间,小菜蛾幼虫约有3个数量高峰,分别为7月初、7月末和8月下旬,秋季数量高于春夏季.在供试的11种杀虫剂中,溴虫腈对小菜蛾幼虫的毒力最高,LC50为0.22 mg·L-1;其次为多杀菌素、氯虫苯甲酰胺、氟虫腈和BT,LC50分别为0.82 ~0.83、1.09、1.36和3.41 mg·L-1;再次为茚虫威和阿维菌素,LC50分别为15.74 mg·L-1和6.03~23.47 mg·L-1;然后为丁醚尿、虫酰肼和啶虫隆,LC50分别为51.30、52.66和61.91 mg·L-1;最低为高效氯氰菊酯,LC50为462.66~673.26 mg·L-1.抗药性测定表明,呼和浩特地区小菜蛾幼虫未对溴虫腈、虫酰肼、氯虫苯甲酰胺和丁醚尿产生抗性,对多杀菌素和氟虫腈为低抗性,对茚虫威和BT为中抗性,对高效氯氰菊酯、啶虫隆和阿维菌素为极高抗性.%The population dynamics and insecticide resistance of the diamondback moth, Plutetla xylostella ( L.) , were investigated on cruciferous vegetables in a Hohhot suburb, and on rapeseed in Wuchuan County, Inner Mongolia from 2009 to 2011. In the suburb of Hohhot city, adult moths began to occur in early April and had four peaks of abundance during the year: late
Chemical and biological insecticides select distinct gene expression patterns in Aedes aegypti mosquito.
Després, Laurence; Stalinski, Renaud; Faucon, Frédéric; Navratil, Vincent; Viari, Alain; Paris, Margot; Tetreau, Guillaume; Poupardin, Rodolphe; Riaz, Muhammad Asam; Bonin, Aurélie; Reynaud, Stéphane; David, Jean-Philippe
Worldwide evolution of mosquito resistance to chemical insecticides represents a major challenge for public health, and the future of vector control largely relies on the development of biological insecticides that can be used in combination with chemicals (integrated management), with the expectation that populations already resistant to chemicals will not become readily resistant to biological insecticides. However, little is known about the metabolic pathways affected by selection with chemical or biological insecticides. Here we show that Aedes aegypti, a laboratory mosquito strain selected with a biological insecticide (Bacillus thuringiensis israelensis, Bti) evolved increased transcription of many genes coding for endopeptidases while most genes coding for detoxification enzymes were under-expressed. By contrast, in strains selected with chemicals, genes encoding detoxification enzymes were mostly over-expressed. In all the resistant strains, genes involved in immune response were under-transcribed, suggesting that basal immunity might be a general adjustment variable to compensate metabolic costs caused by insecticide selection. Bioassays generally showed no evidence for an increased susceptibility of selected strains towards the other insecticide type, and all chemical-resistant strains were as susceptible to Bti as the unselected parent strain, which is a good premise for sustainable integrated management of mosquito populations resistant to chemicals.
Insects resistance bioassay and insecticide penetration biology%昆虫抗药性测定与杀虫剂穿透生物学
Institute of Scientific and Technical Information of China (English)
杨健; 王真; 姚安庆
论文阐明了杀虫剂穿透生物学的基本概念及其对昆虫抗药性测定的指导意义;论述了杀虫剂穿透生物学提出的背景及其与"田间毒理学"的关系,分析了在昆虫抗药性生物测定中存在的问题及其主要原因;提出了杀虫剂穿透生物学在昆虫抗药性测定中的应用原则.%This paper sets out the basic concepts of pesticide penetration biology and the determination of insect resistance. The main problems of resistance in insect bioassays are discussed with reference to the principles of pesticide penetration biology.
Loss of protection with insecticide-treated nets against pyrethroid-resistant Culex quinquefasciatus mosquitoes once nets become holed: an experimental hut study
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Full Text Available Abstract Background An important advantage of pyrethroid-treated nets over untreated nets is that once nets become worn or holed a pyrethroid treatment will normally restore protection. The capacity of pyrethroids to kill or irritate any mosquito that comes into contact with the net and prevent penetration of holes or feeding through the sides are the main reasons why treated nets continue to provide protection despite their condition deteriorating over time. Pyrethroid resistance is a growing problem among Anopheline and Culicine mosquitoes in many parts of Africa. When mosquitoes become resistant the capacity of treated nets to provide protection might be diminished, particularly when holed. An experimental hut trial against pyrethroid-resistant Culex quinquefasciatus was therefore undertaken in southern Benin using a series of intact and holed nets, both untreated and treated, to assess any loss of protection as nets deteriorate with use and time. Results There was loss of protection when untreated nets became holed; the proportion of mosquitoes blood feeding increased from 36.2% when nets were intact to between 59.7% and 68.5% when nets were holed to differing extents. The proportion of mosquitoes blood feeding when treated nets were intact was 29.4% which increased to 43.6–57.4% when nets were holed. The greater the number of holes the greater the loss of protection regardless of whether nets were untreated or treated. Mosquito mortality in huts with untreated nets was 12.9–13.6%; treatment induced mortality was less than 12%. The exiting rate of mosquitoes into the verandas was higher in huts with intact nets. Conclusion As nets deteriorate with use and become increasingly holed the capacity of pyrethroid treatments to restore protection is greatly diminished against resistant Culex quinquefasciatus mosquitoes.
Resistance Risk Assessment of Spodoptera frugiperda (Lepidoptera: Noctuidae) and Diatraea saccharalis (Lepidoptera: Crambidae) to Vip3Aa20 Insecticidal Protein Expressed in Corn.
Bernardi, Oderlei; Bernardi, Daniel; Amado, Douglas; Sousa, Renan S; Fatoretto, Julio; Medeiros, Fernanda C L; Conville, Jared; Burd, Tony; Omoto, Celso
Transgenic Agrisure Viptera 3 corn that expresses Cry1Ab, Vip3Aa20, and EPSPS proteins and Agrisure Viptera expressing Vip3Aa20 are used for control of Spodoptera frugiperda (J.E. Smith) and Diatraea saccharalis (F.) in Brazil. To support a resistance management program, resistance risk assessment studies were conducted to characterize the dose expression of Vip3Aa20 protein and level of control against these species. The Vip3Aa20 expression in Agrisure Viptera 3 and Agrisure Viptera decreased from V6 to V10 stage of growth. However, Vip3Aa20 expression in Agrisure Viptera 3 at V6 and V10 stages was 13- and 16-fold greater than Cry1Ab, respectively. The Vip3Aa20 expression in lyophilized tissue of Agrisure Viptera 3 and Agrisure Viptera diluted 25-fold in an artificial diet caused complete larval mortality of S. frugiperda and D. saccharalis. In contrast, lyophilized tissue of Bt11 at the same dilution does not provide complete mortality of these species. Agrisure Viptera 3 and Agrisure Viptera also caused a high level of mortality against S. frugiperda and D. saccharalis. Moreover, 100% mortality was observed for S. frugiperda larvae (neonates through fifth-instar larvae) when fed in corn with the Vip trait technology. Viptera corn achieves a high level of control against S. frugiperda and D. saccharalis providing a high dose, which is an important determination to support the refuge strategy for an effective resistance management program.
[Obtainment of transgenic wheat with the insecticidal lectin from snowdrop (Galanthus nivalis agglutinin; GNA) gene and analysis of resistance to aphid].
Liang, Hui; Zhu, Yin-Feng; Zhu, Zhen; Sun, Dong-Fa; Jia, Xu
Snowdrop lectin (Galanthus nivalis agglutinin; GNA) is toxic to sap sucking injurious insects of Homopteran. A new gna gene has been transferred into common spring wheat Zhong60634 and winter wheat Yumai66 with high yield by using the biolistic transformation method. Transgenic wheat plants have been obtained in both of the two varieties. Two transgenic plants (T0) have been obtained from the bombarded 535 immature embryos of Zhong60634. Bioassay results show that the development of aphid could be slowed down and the survival rate of young aphid could be reduced by gna gene. Seventeen transgenic plants (T0) were obtained from the bombarded 4636 immature embryos of Yumai66. Twenty plantlets with good resistance to Rhopalosiphum padi and Macrosiphum avenae, which are mainly aphid in north wheat area, were identified from the transgenic plants of T1 generation that came from 8 T0 transgenic plants with good resistance to aphid. The anti-aphid bioassay shows that resistance to the different grain aphid is not the same in transgenic wheat plants. To Rhopalosiphum padi, the rate of survival aphid 8 days after exposing transgenic plants to aphids is significantly lower than that of nontransgenic plants. To Macrosiphum avenae, growth speed of aphids is slowed down but not killed. At the same time, the death rate of young aphids is increased. Anyway, feeding of the two kinds of aphids has been controlled in a certain degree by gna gene when aphids can free to move in plants.
广东省韶关市白纹伊蚊抗药性现状调查%Investigation on the current status of Aedes albopictus resistance to commonly used insecticides in Shaoguan
Institute of Scientific and Technical Information of China (English)
邓惠; 刘旭振; 蓝志忠; 胡应辉; 邹钦
Objective In order to provide a basis for scientific and reasonable use of pesticides, we investigated the resistance of Aedes albopictus to commonly used insecticides in urban area of Shaoguan city. Methods WHO standard bioassay method was applied to calculate LC50 and to obtain resistance index by comparing with susceptible strains. Results The median lethal concentration of Ae. albopictus to beta⁃cypermethrin, decamethrin, dichlorvos, propoxur are 0.0036, 0.0060, 0.2606, 2.1266 mg/L respectively. The resistance index are 3.60, 2.73, 1.53, 1.24 respectively. Conclusion Aedes albopictus in urban area of Shaoguan had low level resistance to beta⁃cypermethrin and decamethrin. It is important to alternate pesticides and choose appropriate doses in mosquito prevention and control.%目的:调查韶关市白纹伊蚊对常用杀虫剂的抗药性,为科学合理使用杀虫剂提供依据。方法按照WHO生物测试法,计算半数致死浓度(LC50)并与敏感品系进行比较得出抗性指数。结果韶关市白纹伊蚊对溴氰菊酯、高效氯氰菊酯、敌敌畏、残杀威的LC50分别为0.0036、0.0060、0.2606和2.1266 mg/L,抗性指数分别为3.60、2.73、1.53和1.24倍。结论韶关市白纹伊蚊对溴氰菊酯、高效氯氰菊酯杀虫剂已产生低度抗性,在实际防治中应注意轮换、合理用药。
Distribution of ace-1R and resistance to carbamates and organophosphates in Anopheles gambiae s.s. populations from Côte d'Ivoire
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Ahoua Alou Ludovic P
Full Text Available Abstract Background The spread of pyrethroid resistance in Anopheles gambiae s.s. is a critical issue for malaria vector control based on the use of insecticide-treated nets. Carbamates and organophosphates insecticides are regarded as alternatives or supplements to pyrethroids used in nets treatment. It is, therefore, essential to investigate on the susceptibility of pyrethroid resistant populations of An. gambiae s.s. to these alternative products. Methods In September 2004, a cross sectional survey was conducted in six localities in Côte d'Ivoire: Toumbokro, Yamoussoukro, Toumodi in the Southern Guinea savannah, Tiassalé in semi-deciduous forest, then Nieky and Abidjan in evergreen forest area. An. gambiae populations from these localities were previously reported to be highly resistant to pyrethroids insecticides. Anopheline larvae were collected from the field and reared to adults. Resistance/susceptibility to carbamates (0.4% carbosulfan, 0.1% propoxur and organophosphates (0.4% chlorpyrifos-methyl, 1% fenitrothion was assessed using WHO bioassay test kits for adult mosquitoes. Then, PCR assays were run to determine the molecular forms (M and (S, as well as phenotypes for insensitive acetylcholinesterase (AChE1 due to G119S mutation. Results Bioassays showed carbamates (carbosulfan and propoxur resistance in all tested populations of An. gambiae s.s. In addition, two out of the six tested populations (Toumodi and Tiassalé were also resistant to organophosphates (mortality rates ranged from 29.5% to 93.3%. The M-form was predominant in tested samples (91.8%. M and S molecular forms were sympatric at two localities but no M/S hybrids were detected. The highest proportion of S-form (7.9% of An. gambiae identified was in sample from Toumbokro, in the southern Guinea savannah. The G119S mutation was found in both M and S molecular forms with frequency from 30.9 to 35.2%. Conclusion This study revealed a wide distribution of insensitive
Neurological symptoms among Sri Lankan farmers occupationally exposed to acetylcholinesterase-inhibiting insecticides
Smit, L.A.M.; Wendel- de Joode, B.N. van; Heederik, D.; Peiris-John, R.J.; Hoek, W. van der
Background: In many agricultural districts in Sri Lanka, pesticide poisoning is a leading cause of death. This study aims to evaluate the impact of pesticide use on Sri Lankan farmers' health. Methods: A total of 260 subjects were surveyed in both a low and a high exposure period. Acetylcholinestera
Comparison of three transgenic Bt rice lines for insecticidal protein expression and resistance against a target pest, Chilo suppressalis (Lepidoptera: Crambidae).
Wang, Ya-Nan; Ke, Kai-Qie; Li, Yun-He; Han, Lan-Zhi; Liu, Yan-Min; Hua, Hong-Xia; Peng, Yu-Fa
Two transgenic rice lines (T2A-1 and T1C-19b) expressing cry2A and cry1C genes, respectively, were developed in China, targeting lepidopteran pests including Chilo suppressalis (Walker) (Lepidoptera: Crambidae). The seasonal expression of Cry proteins in different tissues of the rice lines and their resistance to C. suppressalis were assessed in comparison to a Bt rice line expressing a cry1Ab/Ac fusion gene, Huahui 1, which has been granted a biosafety certificate. In general, levels of Cry proteins were T2A-1 > Huahui 1 > T1C-19b among rice lines, and leaf > stem > root among rice tissues. The expression patterns of Cry protein in the rice line plants were similar: higher level at early stages than at later stages with an exception that high Cry1C level in T1C-19b stems at the maturing stage. The bioassay results revealed that the three transgenic rice lines exhibited significantly high resistance against C. suppressalis larvae throughout the rice growing season. According to Cry protein levels in rice tissues, the raw and corrected mortalities of C. suppressalis caused by each Bt rice line were the highest in the seedling and declined through the jointing stage with an exception for T1C-19b providing an excellent performance at the maturing stage. By comparison, T1C-19b exhibited more stable and greater resistance to C. suppressalis larvae than T2A-1, being close to Huahui 1. The results suggest cry1C is an ideal Bt gene for plant transformation for lepidopteran pest control, and T1C-19b is a promising Bt rice line for commercial use for tolerating lepidopteran rice pests.
Insecticidal and Repellent Activit ies of Laurinterol from the Okinawan Red Alga Laurencia nidifica
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Takahiro Ishii
Full Text Available An ethyl acetate (EtOAc extract of Laurencia nidifica was found to have toxic effect against brine shrimp larvae (Artemia salina. Bioassay-guided fractionation of the EtOAc extract resulted in the isolation of four known halogenated sesquiterpenes, laurinterol (1, isolaurinterol (2, aplysin (3, and a -bromocuparene (4. Their structures were established on the basis of spectral analysis and comparison with literature data. Among isolated compounds, only laurinterol showed strong toxicity against A. salina. Further experiments revealed that laurinterol also exhibited repellent activity against the maize weevil Sitophilus zeamais , insecticidal activity against the termite Reticulitermes speratus, and acetylcholinesterase (AChE inhibitory effect . This is the first report of insecticidal and repellent activities of laurinterol.
Dosis diagnóstica y umbral de resistencia de Lutzomyia evansi (Diptera: Psychodidae, a dos insecticidas utilizados en salud pública en Colombia: deltametrina y lambdacihalotrina Diagnostic dose and resistance threshold to Lutzomyia evansi (Diptera: Psychodidae for two insecticides used in public health in Colombia: deltamethrin and lambdacyhalothrin
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Caterine Henriquez
Full Text Available Los insecticidas son una herramienta importante para el control de los insectos transmisores de microorganismos patógenos. El objetivo de este estudio fue determinar la dosis diagnóstica de deltametrina y lambdacihalotrina en el flebotomíneo Lutzomyia evansi (Núñez-Tovar, vector de Leishmania infantum en Colombia. Los insectos se recolectaron en la Estación Experimental de Fauna Silvestre de Colosó, Sucre, un área de reserva natural que no ha sido sometida a presión con insecticidas. Los bioensayos se realizaron en botellas de vidrio, siguiendo el método simplificado de determinación de resistencia del CDC. En los experimentos, se usaron hembras silvestres de L. evansi que fueron expuestas a diferentes concentraciones de los insecticidas por espacio de 80 minutos, tiempo de duración de la prueba. Los valores de dosis diagnóstica hallados fueron 0,00035% para lambdacihalotrina y 0,0007% para deltametrina, con un umbral de resistencia de diez minutos para ambos insecticidas, tiempo en el cual se alcanza una mortalidad del 100%. Los datos de tiempo-mortalidad indican que la lambdacihalotrina tiene un efecto letal sobre L. evansi en menor concentración que la deltametrina, mientras que la última fue menos tóxica.Insecticides are an important tool for controlling insect vectors of microorganism pathogens. The aim of this study was to determine the diagnostic dosages of deltamethrin and lambdacyhalothrin for the sand fly Lutzomyia evansi (Núñez-Tovar, a vector of Leishmania infantum in Colombia. Sand flies were collected in the Estación Experimental de Fauna Silvestre of Colosó, Sucre, a natural reserve that had not been previously treated with insecticides. Glass bottles were used for bioassays, following the simplified method (CDC for detecting insecticide resistance. Wild females of L. evansi were exposed to different concentrations of insecticides during a test period of 80 minutes. The diagnostic dosages of deltamethrin and
The Wiggle Index: An Open Source Bioassay to Assess Sub-Lethal Insecticide Response in Drosophila melanogaster.
Denecke, Shane; Nowell, Cameron J; Fournier-Level, Alexandre; Perry, Trent; Batterham, Phil
Toxicological assays measuring mortality are routinely used to describe insecticide response, but sub-lethal exposures to insecticides can select for resistance and yield additional biological information describing the ways in which an insecticide impacts the insect. Here we present the Wiggle Index (WI), a high-throughput method to quantify insecticide response by measuring the reduction in motility during sub-lethal exposures in larvae of the vinegar fly Drosophila melanogaster. A susceptible wild type strain was exposed to the insecticides chlorantraniliprole, imidacloprid, spinosad, and ivermectin. Each insecticide reduced larval motility, but response times and profiles differed among insecticides. Two sets of target site mutants previously identified in mortality studies on the basis of imidacloprid or spinosad resistance phenotypes were tested. In each case the resistant mutant responded significantly less than the control. The WI was also able to detect a spinosad response in the absence of the primary spinosad target site. This response was not detected in mortality assays suggesting that spinosad, like many other insecticides, may have secondary targets affecting behaviour. The ability of the WI to detect changes in insecticide metabolism was confirmed by overexpressing the imidacloprid metabolizing Cyp6g1 gene in digestive tissues or the central nervous system. The data presented here validate the WI as an inexpensive, generic, sub-lethal assay that can complement information gained from mortality assays, extending our understanding of the genetic basis of insecticide response in D. melanogaster.
The Wiggle Index: An Open Source Bioassay to Assess Sub-Lethal Insecticide Response in Drosophila melanogaster.
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Shane Denecke
Full Text Available Toxicological assays measuring mortality are routinely used to describe insecticide response, but sub-lethal exposures to insecticides can select for resistance and yield additional biological information describing the ways in which an insecticide impacts the insect. Here we present the Wiggle Index (WI, a high-throughput method to quantify insecticide response by measuring the reduction in motility during sub-lethal exposures in larvae of the vinegar fly Drosophila melanogaster. A susceptible wild type strain was exposed to the insecticides chlorantraniliprole, imidacloprid, spinosad, and ivermectin. Each insecticide reduced larval motility, but response times and profiles differed among insecticides. Two sets of target site mutants previously identified in mortality studies on the basis of imidacloprid or spinosad resistance phenotypes were tested. In each case the resistant mutant responded significantly less than the control. The WI was also able to detect a spinosad response in the absence of the primary spinosad target site. This response was not detected in mortality assays suggesting that spinosad, like many other insecticides, may have secondary targets affecting behaviour. The ability of the WI to detect changes in insecticide metabolism was confirmed by overexpressing the imidacloprid metabolizing Cyp6g1 gene in digestive tissues or the central nervous system. The data presented here validate the WI as an inexpensive, generic, sub-lethal assay that can complement information gained from mortality assays, extending our understanding of the genetic basis of insecticide response in D. melanogaster.
New Acetylcholinesterase Inhibitors for Alzheimer's Disease
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Mona Mehta
Full Text Available Acetylcholinesterase (AChE remains a highly viable target for the symptomatic improvement in Alzheimer's disease (AD because cholinergic deficit is a consistent and early finding in AD. The treatment approach of inhibiting peripheral AchE for myasthenia gravis had effectively proven that AchE inhibition was a reachable therapeutic target. Subsequently tacrine, donepezil, rivastigmine, and galantamine were developed and approved for the symptomatic treatment of AD. Since then, multiple cholinesterase inhibitors (ChEI continue to be developed. These include newer ChEIs, naturally derived ChEIs, hybrids, and synthetic analogues. In this paper, we summarize the different types of ChEIs in development and their respective mechanisms of actions. This pharmacological approach continues to be active with many promising compounds.
Método de diagnóstico para el monitoreo de resistencia a insecticidas en poblaciones de "picudo del algodonero", Anthonomus grandis (Coleoptera: Curculionidae A diagnostic test for insecticide resistance monitoring in "cotton boll weevil" Anthonomus grandis (Coleoptera: Curculionidae populations
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Teodoro Stadler
Full Text Available El control de las poblaciones de Anthonomus grandis Boheman, por debajo de su umbral de daño económico durante el ciclo del cultivo del algodón, se realiza en forma efectiva hasta el momento, a través de insecticidas de síntesis. La presión selectiva de las aplicaciones extensivas e intensivas de insecticidas hace imperativa la detección temprana de focos de resistencia a los mismos, en función de un correcto manejo del fenómeno. Se desarrolló un método de diagnóstico de resistencia para A. grandis a partir de la técnica "vial test", que fue adaptada en forma de "kit" para el monitoreo rápido y sencillo de los focos de resistencia en el campo. La toxicidad (CL99, para calcular la concentración discriminante (CD del insecticida y la preparación del "kit", se obtiene a partir de bioensayos de laboratorio con una cepa normal susceptible de A. grandis. Se determinó la vida media de los insecticidas dentro de los viales por CIPAC MT 46, para establecer una fecha de vencimiento del "kit". La CD y el método en su conjunto fueron validados a través de ensayos a campo. El "kit", usado en el monitoreo de resistencia en el campo, fue especialmente diseñado para ser utilizado en las condiciones geográficas, económicas y socio-culturales presentes en la región algodonera argentina. La implementación de esta técnica permitirá conseguir la información necesaria, y así obtener una apropiada alternancia de insecticidas. Como consecuencia, se prevé una reducción de impacto ambiental de las prácticas agronómicas en el control de plagas en algodón.The in-season control of the cotton boll weevil Anthonomus grandis Boheman is done by insecticide application, which so far is the only effective way to reduce boll weevil populations to levels below economic significance. The extensive and intensive control actions with insecticides cause selective pressure on pest populations. Thus, to achieve an accurate insecticide resistance
Domains of Bacillus thuringiensis crystal proteins involved in insecticidal activity
Bosch, H.J.; Schipper, B.; Kleij, van der H.; Maagd, de R.A.; Stiekema, W.J.
The expected increase in application of Bacillus thuringiensis (Bt) in crop protection makes it necessary to anticipate the development of Bt-resistant insects. To safeguard the long-term use of Bt-based insecticides, we studied the mode of action of Bt crystal proteins. CryIA(b), CryIC and CryIE ar
Two Step Synthesis of a Non-symmetric Acetylcholinesterase Reactivator
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Vit Koleckar
Full Text Available The newly developed and very promising acetylcholinesterase reactivator (E-1- (2-hydroxyiminomethylpyridinium-4-(4-hydroxyiminomethylpyridinium-but-2-ene dibromide was prepared using two different pathways via a two-step synthesis involving the appropriate (E-1-(4-bromobut-2-enyl-2- or 4-hydroxyiminomethyl-pyridinium bromides. Afterwards, purities and yields of the desired product prepared by both routes were compared. Finally, its potency to reactivate several nerve agent-inhibited acetylcholinesterases was tested.
Chlorpyrifos Detection by Piezoelectric Biosensor Based on Acetylcholinesterase Immobilization
Institute of Scientific and Technical Information of China (English)
Acetylcholinesterase (AChE) was immobilized on multilayer films assembled by poly diallyldimethylammonium chloride (PDDA) and ι-carrageenan (IC) on silver-coated crystal electrode surfaces to detect the chlorpyrifos belonging to the organophosphates pesticide.Mass sensitive quartz crystal microbalance (QCM) was used to study the effect of AChE concentration and pH of phosphate buffer solution on immobilized acetylcholinesterase.The optimized conditions were as follows: pH was 6.0 which was near isoelectric ...
Sub-acute Toxicity of Carbofuran on Acetylcholinesterase Activity in the Freshwater Catfish, Clarias batrachus
Institute of Scientific and Technical Information of China (English)
The inhibition of acetylcholinesterase (ACHE) activity has been widely used as a biomarker in an animal exposed to the pesticides. However, the interaction of extensively used organocarbamate insecticide, carbofuran, with the nervous system of the aquatic organisms is not properly studied. AChE is a key enzyme which catalyses the hydrolysis of acetylcholine, a neurotransmitter at the neuromuscular junctions, and thus regulates the neurotransmission system. In the present study, we have evaluated the impact of sub-acute concentrations (0.01 and 0.02 mg/L i.e. 1/20th and 1/10th of LC50) of carbofuran on the activity of acetylcholinesterase,from different tissues of Clarias batrachus, a fresh water teleost, after 96 hr and 15 days exposure periods in vivo. The carbofuran significantly reduced the activity of AChE in different tissues of C. batrachus at both concentrations and periods of exposure. The greater inhibition of AChE activities were recorded in fish tissues at higher carbofuran concentration (0.02 mg/L) after longer (15days) treatment period. The inhibition of AChE activity in all fish tissues tested was dependent on pesticide concentration and the duration of treatment. AChE from the tissues of C. batrachus was found to be a true cholinesterase as it was completely inhibited by the small concentration (nM) of eserine as tested in vitro. It was found that carbofuran at very low concentration exerted significant inhibitory effect on AChE activity in fish tissues.
Impact of pesticide resistance on toxicity and tolerance of hostplant phytochemicals in Amyelois transitella (Lepidoptera: Pyralidae)
For some polyphagous insects adaptation to phytochemically novel plants confers enhanced resistance to insecticides, but whether insecticide resistance enhances tolerance to novel phytochemicals has not been assessed. We used Amyelois transitella Walker (navel orangeworm), an economically important ...
Effects of the synthetic pyrethroid insecticide, permethrin, on two estuarine fish species.
Parent, Lindsey M; Delorenzo, Marie E; Fulton, Michael H
Limited toxicity data are available for estuarine and marine species and the widely used pyrethroid insecticide, permethrin. This study determined acute effects of permethrin on survival, lipid peroxidation, acetylcholinesterase activity, and splenocyte proliferation for two fish species found in South Carolina estuaries; juvenile red drum (Sciaenops ocellatus) and adult mummichog (Fundulus heteroclitus). Juvenile S. ocellatus were significantly more sensitive than adult F. heteroclitus to permethrin exposure, with a 96-h LC50 value of 8 μg/L determined for red drum compared to 23 μg/L for mummichog. Lipid peroxidation activity of the liver increased in permethrin-treated fish compared to control animals after 24 h and decreased after 96 h. Permethrin had no effect on acetylcholinesterase activity of the brain at the concentrations tested. Permethrin exposure significantly inhibited splenocyte proliferation, indicating an immunosuppressive effect. Most of the effects of permethrin on fish cellular stress enzymes and survival occurred at concentrations much higher than those typically measured in the environment. However, inhibition of splenocyte proliferation in juvenile red drum occurred at approximately twice that of measured permethrin concentrations in surface water. These findings may prove useful to the future management and regulation of pyrethroid insecticide use near estuarine habitats.
Identification and Biochemical Properties of Two New Acetylcholinesterases in the Pond Wolf Spider (Pardosa pseudoannulata).
Meng, Xiangkun; Li, Chunrui; Xiu, Chunli; Zhang, Jianhua; Li, Jingjing; Huang, Lixin; Zhang, Yixi; Liu, Zewen
Acetylcholinesterase (AChE), an important neurotransmitter hydrolase in both invertebrates and vertebrates, is targeted by organophosphorus and carbamate insecticides. In this study, two new AChEs were identified in the pond wolf spider Pardosa pseudoannulata, an important predatory natural enemy of several insect pests. In total, four AChEs were found in P. pseudoannulata (including two AChEs previously identified in our laboratory). The new putative AChEs PpAChE3 and PpAChE4 contain most of the common features of the AChE family, including cysteine residues, choline binding sites, the conserved sequence 'FGESAG' and conserved aromatic residues but with a catalytic triad of 'SDH' rather than 'SEH'. Recombinant enzymes expressed in Sf9 cells showed significant differences in biochemical properties compared to other AChEs, such as the optimal pH, substrate specificity, and catalytic efficiency. Among three test substrates, PpAChE1, PpAChE3 and PpAChE4 showed the highest catalytic efficiency (Vmax/KM) for ATC (acetylthiocholine iodide), with PpAChE3 exhibiting a clear preference for ATC based on the VmaxATC/VmaxBTC ratio. In addition, the four PpAChEs were more sensitive to the AChE-specific inhibitor BW284C51, which acts against ATC hydrolysis, than to the BChE-specific inhibitor ISO-OMPA, which acts against BTC hydrolysis, with at least a 8.5-fold difference in IC50 values for each PpAChE. PpAChE3, PpAChE4, and PpAChE1 were more sensitive than PpAChE2 to the tested Carb insecticides, and PpAChE3 was more sensitive than the other three AChEs to the tested OP insecticides. Based on all the results, two new functional AChEs were identified from P. pseudoannulata. The differences in AChE sequence between this spider and insects enrich our knowledge of invertebrate AChE diversity, and our findings will be helpful for understanding the selectivity of insecticides between insects and natural enemy spiders.
Identification and Biochemical Properties of Two New Acetylcholinesterases in the Pond Wolf Spider (Pardosa pseudoannulata.
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Xiangkun Meng
Full Text Available Acetylcholinesterase (AChE, an important neurotransmitter hydrolase in both invertebrates and vertebrates, is targeted by organophosphorus and carbamate insecticides. In this study, two new AChEs were identified in the pond wolf spider Pardosa pseudoannulata, an important predatory natural enemy of several insect pests. In total, four AChEs were found in P. pseudoannulata (including two AChEs previously identified in our laboratory. The new putative AChEs PpAChE3 and PpAChE4 contain most of the common features of the AChE family, including cysteine residues, choline binding sites, the conserved sequence 'FGESAG' and conserved aromatic residues but with a catalytic triad of 'SDH' rather than 'SEH'. Recombinant enzymes expressed in Sf9 cells showed significant differences in biochemical properties compared to other AChEs, such as the optimal pH, substrate specificity, and catalytic efficiency. Among three test substrates, PpAChE1, PpAChE3 and PpAChE4 showed the highest catalytic efficiency (Vmax/KM for ATC (acetylthiocholine iodide, with PpAChE3 exhibiting a clear preference for ATC based on the VmaxATC/VmaxBTC ratio. In addition, the four PpAChEs were more sensitive to the AChE-specific inhibitor BW284C51, which acts against ATC hydrolysis, than to the BChE-specific inhibitor ISO-OMPA, which acts against BTC hydrolysis, with at least a 8.5-fold difference in IC50 values for each PpAChE. PpAChE3, PpAChE4, and PpAChE1 were more sensitive than PpAChE2 to the tested Carb insecticides, and PpAChE3 was more sensitive than the other three AChEs to the tested OP insecticides. Based on all the results, two new functional AChEs were identified from P. pseudoannulata. The differences in AChE sequence between this spider and insects enrich our knowledge of invertebrate AChE diversity, and our findings will be helpful for understanding the selectivity of insecticides between insects and natural enemy spiders.
Effect of organophosphorus insecticides on phosphorylation of the M2 muscarinic acetylcholine receptor
Institute of Scientific and Technical Information of China (English)
Shuyin Li; Liming Zou; Carry Pope
BACKGROUND: Organophosphorus insecticides may promote the accumulation of acetylcholine at synapses and the neuromuscular junction by inhibiting acetylcholinesterase activity to cause disturbance of neural signal conduction and induce a toxic reaction. Organophosphorus insecticides may act on M2 muscarinic acetylcholine receptors, whose combination with G proteins is regulated by phosphorylation of G protein-coupled receptor kinase 2.OBJECTIVE: To investigate the effects of organophosphorus insecticides on the phosphorylation of G protein-coupled receptor kinase 2-mediated M2 muscarinic acetylcholine receptors and to reveal other possible actions of organophosphorus insecticides.DESIGN, TIME AND SETTING: An observational study, which was performed in the Central Laboratory of Shenyang Medical College, and Department of Physiological Sciences, College of Veterinary Medicine, Oklahoma State University from June 2002 to December 2004.METHODS: The M2 muscarinic acetylcholine receptor was extracted and purified from pig brain using affinity chromatography. Subsequently, the purified M2 muscarinic acetylcholine receptor, G protein-coupled receptor kinase 2, and [OP32] ATP were incubated with different concentrations of paraoxon and chlorpyrifos oxon together. The mixture then underwent polyacrylamide gel electrophoresis, and the gel film was dried and radioactively autographed to detect phosphorylation of the M2 muscarinic acetylcholine receptor. Finally, the radio-labeled phosphorylated M2 receptor protein band was excised for counting with an isotope liquid scintillation counter.MAIN OUTCOME MEASURES: Effects of chlorpyrifos oxon, paraoxon, chlorpyrifos, and parathion in different concentrations on the phosphorylation of the M2 muscarinic acetylcholine receptor; effects of chlorpyrifos oxon on the phosphorylation of the adrenergic receptor.CONCLUSION: Different kinds of organophosphorus insecticides have different effects on the phosphorylation of the G protein
Effects of Four Insecticides on Respiratory Metabolism of Resistant Cotton Bollworm Larvae%4种杀虫剂对棉铃虫抗药性种群幼虫呼吸代谢的影响
Institute of Scientific and Technical Information of China (English)
王开运; 姜兴印; 仪美芹; 孙学振
The 5 instar larvae of susceptible and resistant populations of cotton bollworm Helicoverpa armigera (Hübner) were treated with fenvalerate, methomyl, parathion-methyl and endosulfan at the LD50 and LD95 dosages. The effects of 4 insecticides on respiratory metabolism to 5 instar larvae were measured. The results showed that although the dosages at the LD50 of fenvalerate and methomyl to R-population were 15.8 and 14.1 fold higher than that of S-population, but the respiratory inhibitory rate of R-population were lower than S-population.The respiratory inhibitory rates of parathion-methyl and endosulfan at LD50 dosages to R-population were lower than that S-population after treating 300~1440 min. At the LD95 dosages, the respiratory inhibotory rates of fenvalerate and parathion-methyl to R-population were 14.7%~27.3% and 27.2%~15.5%,to S-population were 42.0%~48.6% and 45.8%~50.4%. It showed that the endurance abilities of R-population to insecticides and respiratory metabolism were higher than that of S-population.%利用LD50及LD95剂量的氰戊菊酯、灭多威、甲基对硫磷和硫丹4种杀虫剂,分别处理棉铃虫Helicoverpa armigra Hübner敏感和抗药性种群的5龄幼虫,测定各药剂对幼虫呼吸代谢的影响。结果表明,以LD50计,氰戊菊酯和灭多威对抗药性种群的处理剂量分别是敏感种群的15.8和14.1倍,但其呼吸抑制率却显著降低;用甲基对硫磷、硫丹处理300~1 440 min对抗药性种群的呼吸抑制率也低于对敏感种群。在LD95剂量下,用氰戊菊酯、甲基对硫磷处理10~60 min对抗性种群呼吸抑制率分别为14.7%~27.3%和27.2%~15.5%,而对敏感种群则分别达42.0%~48.6%和45.8%~50.4%。
Sensitivity of Bemisia tabaci (Hemiptera: Aleyrodidae) to several new insecticides in China: effects of insecticide type and whitefly species, strain, and stage.
Xie, Wen; Liu, Yang; Wang, Shaoli; Wu, Qingjun; Pan, Huipeng; Yang, Xin; Guo, Litao; Zhang, Youjun
Whitefly biotypes B and Q are the two most damaging members of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex. Control of B. tabaci (and especially of Q) has been impaired by resistance to commonly used insecticides. To find new insecticides for B. tabaci management in China, we investigated the sensitivity of eggs, larvae, and adults of laboratory strains of B and Q (named Lab-B and Lab-Q) and field strains of Q to several insecticides. For eggs, larvae, and adults of B. tabaci and for six insecticides (cyantraniliprole, chlorantraniliprole, pyriproxyfen, buprofezin, acetamiprid, and thiamethoxam), LC50 values were higher for Lab-Q than for Lab-B; avermectin LC50 values, however, were low for adults of both Lab-Q and Lab-B. Based on the laboratory results, insecticides were selected to test against eggs, larvae, and adults of four field strains of B. tabaci Q. Although the field strains differed in their sensitivity to the insecticides, the eggs and larvae of all strains were highly sensitive to cyantraniliprole, and the adults of all strains were highly sensitive to avermectin. The eggs, larvae, and adults of B. tabaci Q were generally more resistant than those of B. tabaci B to the tested insecticides. B. tabaci Q eggs and larvae were sensitive to cyantraniliprole and pyriproxyfen, whereas B. tabaci Q adults were sensitive to avermectin. Field trials should be conducted with cyantraniliprole, pyriproxyfen, and avermectin for control of B. tabaci Q and B in China.
旅客列车德国小蠊对5种杀虫剂的抗药性监测%Resistance surveillance of Blattella germanica to five kinds of insecticides in passenger train
Institute of Scientific and Technical Information of China (English)
米登书; 陈明超; 王彦恒; 马建民; 蒋邓桓; 朱湘仪
Objective To investigate the resistance of Blattella germanica to acephate, propoxur,clocythrin,betacypermethrin and fipronil.Methods Residual smearing and contacting method.Results On the basis of KT50,the beta-cypermethrin was the shortest, the fipronil was the longest, and from short to long the sequence were betacypermethrin, propoxur, clocythrin, acephate and fipronil.The Blattella germanica had emerged high resistance to fipronil( R > 30) ,resistance coefficient to beta-cypermethrin and clocythrin were 6.30 and 3.69 respectively, and resistance coefficient to propoxur was below 2 but the deadly effect during 24 h was 46.67%.Conclusion The Blattella germanica from passenger train were sensitive to acephate, and should give priority to consider using it,reduce the use of fipronil ,beta-cypermethrin and clocythrin ,use propoxur carefully ,and use insecticides in a planned way by turns.%目的 研究旅客列车德国小蠊对乙酰甲胺磷、残杀威、三氟氯氰菊酯、高效氯氰菊酯、氟虫腈等杀虫剂的抗药性.方法 采用WHO推荐的果酱瓶药膜法.结果 KT50最短为高效氯氰菊酯(19 min),最长为氟虫腈(>120 min).从低到高按高效氯氰菊酯、残杀威、三氟氯氰菊酯、乙酰甲胺磷、氟虫腈顺序排列.氟虫睛抗性系数>30,属高抗;高效氯氰菊酯的抗性系数为6.30,三氟氯氰菊酯的抗性系数为3.69,已产生抗药性;残杀威抗性系数<2,但24 h致死效果下降率达46.67%,说明亦产生抗药性.乙酰甲胺磷的抗性系数为1,致死效果下降率较低.结论 旅客列车德国小蠊对乙酰甲胺磷较敏感,提示在今后的防治工作中可考虑优先使用,同时应减少氟虫腈、高效氯氰菊酯、三氟氯氰菊酯的使用量,慎用残杀威,有计划地交替、轮换用药.
咸阳市淡色库蚊对5种杀虫剂的抗药性研究及防制对策%Resistance of Culex pipiens pallens to five insecticides in Xianyang city and the corresponding control strategies
Institute of Scientific and Technical Information of China (English)
孙亮; 吕文; 孙养信
Objective To identify the resistance of Culex pipiens pattens to five commonly used insecticides in Xianyang city so as to provide evidence for control strategy development. Methods The mortality of larvae exposed to five insecticides was determined by the distinguishing dosage method. Results The resistance level of Cx. Pipwns pattens was high under the diagnosis dose to DDT, DDVP, permethrin, and deltamethrin, and the mortality in 24 hours was 23.45%, 14.02%, 28.77%, 25.00%, respectively. The resistance to cypermethrin was moderate and the mortality was 58.63%. Conclusion The resistance of Cx. Pipiens pallens to five commonly used insecticides in Xianyang has reached middle to high levels. Different kinds of insecticides should be used for control of mosquitoes.%目的 了解咸阳市淡色库蚊对5种杀虫剂的抗药性现状,为制定防制对策提供科学依据.方法 采用区分剂量法测定淡色库蚊幼虫对5种杀虫剂的24 h死亡率.结果 咸阳市淡色库蚊对DDT、敌敌畏、氯菊酯和溴氰菊酯的抗性均达到高抗以上,24 h死亡率分别为23.45%、14.02%、28.77%和25.00%;对氯氰菊酯的抗性达到中抗以上,24 h死亡率为58.63%.结论 咸阳市淡色库蚊对5种杀虫剂均产生了不同程度的抗药性,今后在这些地区进行蚊虫防治时应考虑换用其他种类的杀虫剂.
Susceptibility of Anopheles maculipennis to different classes of insecticides in West Azarbaijan Province, Northwestern Iran
Institute of Scientific and Technical Information of China (English)
Ali; Reza; Chavshin; Farrokh; Dabiri; Hassan; Vatandoost; Mulood; Mohammadi; Bavani
Objective: To determine the susceptibility status of Anopheles maculipennis(An. maculipennis) against the major insecticides used in the health sectors in West Azarbaijan Province, Northwestern Iran.Methods: Unfed 3-5 days old adult females of An. maculipennis were collected across the West Azarbaijan Province and were subjected to evaluation of their susceptibility following World Health Organization recommended protocol against six insecticides(permethrin, deltamethrin, propoxur, bendiocarb, malathion and dieldrin) belonging to four different classes. Results: In this study, 916 specimens of An. maculipennis were examined against the insecticides which indicated that An. maculipennis was tolerant to permethrin, deltamethrin and dielderin, but displayed resistance against propoxur, bendiocarb and malathion. Conclusions: The pattern of resistance in An. maculipennis could be attributed to the agricultural landscapes, agricultural pesticides used and the exposure of the mosquitoes to insecticides. Logical cooperation is needed between the agriculture and health sectors to ensure the judicious use of pesticides in each sector and the management of probable resistance.
Pralidoxime in acute organophosphorus insecticide poisoning--a randomised controlled trial.
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Michael Eddleston
Full Text Available BACKGROUND: Poisoning with organophosphorus (OP insecticides is a major global public health problem, causing an estimated 200,000 deaths each year. Although the World Health Organization recommends use of pralidoxime, this antidote's effectiveness remains unclear. We aimed to determine whether the addition of pralidoxime chloride to atropine and supportive care offers benefit. METHODS AND FINDINGS: We performed a double-blind randomised placebo-controlled trial of pralidoxime chloride (2 g loading dose over 20 min, followed by a constant infusion of 0.5 g/h for up to 7 d versus saline in patients with organophosphorus insecticide self-poisoning. Mortality was the primary outcome; secondary outcomes included intubation, duration of intubation, and time to death. We measured baseline markers of exposure and pharmacodynamic markers of response to aid interpretation of clinical outcomes. Two hundred thirty-five patients were randomised to receive pralidoxime (121 or saline placebo (114. Pralidoxime produced substantial and moderate red cell acetylcholinesterase reactivation in patients poisoned by diethyl and dimethyl compounds, respectively. Mortality was nonsignificantly higher in patients receiving pralidoxime: 30/121 (24.8% receiving pralidoxime died, compared with 18/114 (15.8% receiving placebo (adjusted hazard ratio [HR] 1.69, 95% confidence interval [CI] 0.88-3.26, p = 0.12. Incorporating the baseline amount of acetylcholinesterase already aged and plasma OP concentration into the analysis increased the HR for patients receiving pralidoxime compared to placebo, further decreasing the likelihood that pralidoxime is beneficial. The need for intubation was similar in both groups (pralidoxime 26/121 [21.5%], placebo 24/114 [21.1%], adjusted HR 1.27 [95% CI 0.71-2.29]. To reduce confounding due to ingestion of different insecticides, we further analysed patients with confirmed chlorpyrifos or dimethoate poisoning alone, finding no evidence of
A renaissance for botanical insecticides?
Isman, Murray B
Botanical insecticides continue to be a subject of keen interest among the international research community, reflected in the steady growth in scientific publications devoted to the subject. Until very recently though, the translation of that theory to practice, i.e. the commercialisation and adoption of new botanical insecticides in the marketplace, has seriously lagged behind. Strict regulatory regimes, long the bane of small pesticide producers, are beginning to relax some of the data requirements for 'low-risk' pesticide products, facilitating movement of more botanicals into the commercial arena. In this paper I discuss some of the jurisdictions where botanicals are increasingly finding favour, some of the newer botanical insecticides in the plant and animal health arsenal and some of the specific sectors where botanicals are most likely to compete effectively with other types of insecticidal product.
Acetylcholinesterase modulates neurite outgrowth on fibronectin.
Giordano, C; Poiana, G; Augusti-Tocco, G; Biagioni, S
Acetylcholinesterase (AChE) has been reported to be involved in the modulation of neurite outgrowth. To understand the role played by different domains, we transfected neuroblastoma cells with three constructs containing the invariant region of AChE, differing in the exon encoding the C-terminus and therefore in AChE cellular fate and localization. All isoforms increased neurite extension, suggesting the involvement of the invariant domain [A. De Jaco, G. Augusti-Tocco, S. Biagioni, Alternative AChE molecular forms exhibit similar ability to induce neurite outgrowth, J. Neurosci. Res. 70 (2002) 756-765]. The peripheral anionic site (PAS) is encoded by invariant exons and represents the domain involved in non-cholinergic functions of AChE. Masking of PAS with fasciculin results in a significant decrease of neurite outgrowth in all clones overexpressing AChE. A strong reduction was also observed when clones were cultured on fibronectin. Treatment of clones with fasciculin, therefore masking PAS, abolished the fibronectin-induced reduction. The inhibition of the catalytic site cannot revert the fibronectin effect. Finally, when clones were cultured on fibronectin in the presence of heparin, a ligand of fibronectin, the inhibitory effect was completely reversed. Our results indicate that PAS could directly or indirectly mediate AChE/fibronectin interactions.
Contrasting patterns of tolerance between chemical and biological insecticides in mosquitoes exposed to UV-A.
Tetreau, Guillaume; Chandor-Proust, Alexia; Faucon, Frédéric; Stalinski, Renaud; Akhouayri, Idir; Prud'homme, Sophie M; Raveton, Muriel; Reynaud, Stéphane
Mosquitoes are vectors of major human diseases, such as malaria, dengue or yellow fever. Because no efficient treatments or vaccines are available for most of these diseases, control measures rely mainly on reducing mosquito populations by the use of insecticides. Numerous biotic and abiotic factors are known to modulate the efficacy of insecticides used in mosquito control. Mosquito breeding sites vary from opened to high vegetation covered areas leading to a large ultraviolet gradient exposure. This ecological feature may affect the general physiology of the insect, including the resistance status against insecticides. In the context of their contrasted breeding sites, we assessed the impact of low-energetic ultraviolet exposure on mosquito sensitivity to biological and chemical insecticides. We show that several mosquito detoxification enzyme activities (cytochrome P450, glutathione S-transferases, esterases) were increased upon low-energy UV-A exposure. Additionally, five specific genes encoding detoxification enzymes (CYP6BB2, CYP6Z7, CYP6Z8, GSTD4, and GSTE2) previously shown to be involved in resistance to chemical insecticides were found over-transcribed in UV-A exposed mosquitoes, revealed by RT-qPCR experiments. More importantly, toxicological bioassays revealed that UV-exposed mosquitoes were more tolerant to four main chemical insecticide classes (DDT, imidacloprid, permethrin, temephos), whereas the bioinsecticide Bacillus thuringiensis subsp. israelensis (Bti) appeared more toxic. The present article provides the first experimental evidence of the capacity of low-energy UV-A to increase mosquito tolerance to major chemical insecticides. This is also the first time that a metabolic resistance to chemical insecticides is linked to a higher susceptibility to a bioinsecticide. These results support the use of Bti as an efficient alternative to chemical insecticides when a metabolic resistance to chemicals has been developed