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Identification of genes associated with growth cessation and bud dormancy entrance using a dormancy-incapable tree mutant
Microsoft Academic Search
BACKGROUND: In many tree species the perception of short days (SD) can trigger growth cessation, dormancy entrance, and the establishment of a chilling requirement for bud break. The molecular mechanisms connecting photoperiod perception, growth cessation and dormancy entrance in perennials are not clearly understood. The peach [Prunus persica (L.) Batsch] evergrowing (evg) mutant fails to cease growth and therefore cannot
Sergio Jiménez; Zhigang Li; Gregory L Reighard; Douglas G Bielenberg
Epigenetic regulation of bud dormancy events in perennial plants.
Release of bud dormancy in perennial plants resembles vernalization in Arabidopsis thaliana and cereals. In both cases, a certain period of chilling is required for accomplishing the reproductive phase, and several transcription factors with the MADS-box domain perform a central regulatory role in these processes. The expression of DORMANCY-ASSOCIATED MADS-box (DAM)-related genes has been found to be up-regulated in dormant buds of numerous plant species, such as poplar, raspberry, leafy spurge, blackcurrant, Japanese apricot, and peach. Moreover, functional evidence suggests the involvement of DAM genes in the regulation of seasonal dormancy in peach. Recent findings highlight the presence of genome-wide epigenetic modifications related to dormancy events, and more specifically the epigenetic regulation of DAM-related genes in a similar way to FLOWERING LOCUS C, a key integrator of vernalization effectors on flowering initiation in Arabidopsis. We revise the most relevant molecular and genomic contributions in the field of bud dormancy, and discuss the increasing evidence for chromatin modification involvement in the epigenetic regulation of seasonal dormancy cycles in perennial plants. PMID:24917873
Ríos, Gabino; Leida, Carmen; Conejero, Ana; Badenes, María Luisa
Epigenetic regulation of bud dormancy events in perennial plants
PubMed Central
Release of bud dormancy in perennial plants resembles vernalization in Arabidopsis thaliana and cereals. In both cases, a certain period of chilling is required for accomplishing the reproductive phase, and several transcription factors with the MADS-box domain perform a central regulatory role in these processes. The expression of DORMANCY-ASSOCIATED MADS-box (DAM)-related genes has been found to be up-regulated in dormant buds of numerous plant species, such as poplar, raspberry, leafy spurge, blackcurrant, Japanese apricot, and peach. Moreover, functional evidence suggests the involvement of DAM genes in the regulation of seasonal dormancy in peach. Recent findings highlight the presence of genome-wide epigenetic modifications related to dormancy events, and more specifically the epigenetic regulation of DAM-related genes in a similar way to FLOWERING LOCUS C, a key integrator of vernalization effectors on flowering initiation in Arabidopsis. We revise the most relevant molecular and genomic contributions in the field of bud dormancy, and discuss the increasing evidence for chromatin modification involvement in the epigenetic regulation of seasonal dormancy cycles in perennial plants.
Rios, Gabino; Leida, Carmen; Conejero, Ana; Badenes, Maria Luisa
Grape Bud Dormancy Release ? The Molecular Aspect
Grapevine is a woody temperate-zone perennial. As such, it presents a period of active growth from spring to fall, followed\\u000a by a rest period in the winter. Soon after bud burst in the spring, a complex bud is formed within the axil of each leaf on\\u000a the young shoot. In the prophyll of the prompt bud, which may burst within
Transcriptome analysis of chestnut (Castanea sativa) tree buds suggests a putative role for epigenetic control of bud dormancy
Background and Aims Recent papers indicated that epigenetic control is involved in transitions in bud dormancy, purportedly controlling gene expression. The present study aimed to identify genes that are differentially expressed in dormant and non-dormant Castanea sativa buds. Methods Two suppression subtractive hybridization cDNA libraries were constructed to characterize the transcriptomes of dormant apical buds of C. sativa, and buds in which dormancy was released. Key Results A total of 512 expressed sequence tags (ESTs) were generated in a forward and reverse subtractive hybridization experiment. Classification of these ESTs into functional groups demonstrated that dormant buds were predominantly characterized by genes associated with stress response, while non-dormant buds were characterized by genes associated with energy, protein synthesis and cellular components for development and growth. ESTs for a few genes involved in different forms of epigenetic modification were found in both libraries, suggesting a role for epigenetic control in bud dormancy different from that in growth. Genes encoding histone mono-ubiquitinase HUB2 and histone acetyltransferase GCN5L were associated with dormancy, while a gene encoding histone H3 kinase AUR3 was associated with growth. Real-time RT-PCR with a selection of genes involved in epigenetic modification and stress tolerance confirmed the expression of the majority of investigated genes in various stages of bud development, revealing a cyclical expression pattern concurring with the growth seasons for most genes. However, senescing leaves also showed an increased expression of several of the genes associated with dormancy, implying pleiotropy. Furthermore, a comparison between these subtraction cDNA libraries and the poplar bud dormancy transcriptome and arabidopsis transcriptomes for seed dormancy and non-dormancy indicated a common basis for dormancy in all three systems. Conclusions Bud dormancy and non-dormancy in C. sativa were characterized by distinct sets of genes and are likely to be under different epigenetic control.
Santamaria, Maria Estrella; Rodriguez, Roberto; Canal, Maria Jesus; Toorop, Peter E.
Chilling-Dependent Release of Seed and Bud Dormancy in Peach Associates to Common Changes in Gene Expression
Reproductive meristems and embryos display dormancy mechanisms in specialized structures named respectively buds and seeds that arrest the growth of perennial plants until environmental conditions are optimal for survival. Dormancy shows common physiological features in buds and seeds. A genotype-specific period of chilling is usually required to release dormancy by molecular mechanisms that are still poorly understood. In order to
Carmen Leida; Ana Conejero; Vicent Arbona; Aurelio Gómez-Cadenas; Gerardo Llácer; María Luisa Badenes; Gabino Ríos
A Molecular Timetable for Apical Bud Formation and Dormancy Induction in Poplar[W
The growth of perennial plants in the temperate zone alternates with periods of dormancy that are typically initiated during bud development in autumn. In a systems biology approach to unravel the underlying molecular program of apical bud development in poplar (Populus tremula × Populus alba), combined transcript and metabolite profiling were applied to a high-resolution time course from short-day induction to complete dormancy. Metabolite and gene expression dynamics were used to reconstruct the temporal sequence of events during bud development. Importantly, bud development could be dissected into bud formation, acclimation to dehydration and cold, and dormancy. To each of these processes, specific sets of regulatory and marker genes and metabolites are associated and provide a reference frame for future functional studies. Light, ethylene, and abscisic acid signal transduction pathways consecutively control bud development by setting, modifying, or terminating these processes. Ethylene signal transduction is positioned temporally between light and abscisic acid signals and is putatively activated by transiently low hexose pools. The timing and place of cell proliferation arrest (related to dormancy) and of the accumulation of storage compounds (related to acclimation processes) were established within the bud by electron microscopy. Finally, the identification of a large set of genes commonly expressed during the growth-to-dormancy transitions in poplar apical buds, cambium, or Arabidopsis thaliana seeds suggests parallels in the underlying molecular mechanisms in different plant organs.
Ruttink, Tom; Arend, Matthias; Morreel, Kris; Storme, Veronique; Rombauts, Stephane; Fromm, Jorg; Bhalerao, Rishikesh P.; Boerjan, Wout; Rohde, Antje
Identification of genes associated with bud dormancy release in Prunus persica by suppression subtractive hybridization.
To better understand the molecular and physiological mechanisms underlying maintenance and release of seasonal bud dormancy in perennial trees, we identified differentially expressed genes during dormancy progression in reproductive buds from peach (Prunus persica [L.] Batsch) by suppression subtractive hybridization (SSH) and microarray hybridization. Four SSH libraries were constructed, which were respectively enriched in cDNA highly expressed in dormant buds (named DR), in dormancy-released buds (RD) and in the cultivars with different chilling requirement, 'Zincal 5' (ZS) and 'Springlady' (SZ), sampled after dormancy release. About 2500 clones picked from the four libraries were loaded on a glass microarray. Hybridization of microarrays with the final products of SSH procedure was performed in order to validate the selected clones that were effectively enriched in their respective sample. Nearly 400 positive clones were sequenced, which corresponded to 101 different unigenes with diverse functional annotation. We obtained DAM4, 5 and 6 genes coding for MADS-box transcription factors previously related to growth cessation and terminal bud formation in the evergrowing mutant of peach. Several other cDNAs are similar to dormancy factors described in other species, and others have been related to bud dormancy for the first time in this study. Quantitative reverse transcription polymerase chain reaction analysis confirmed differential expression of cDNAs coding for a Zn-finger transcription factor, a GRAS-like regulator, a DNA-binding protein and proteins similar to forisome subunits involved in the reversible occlusion of sieve elements in Fabaceae, among others. PMID:20231169
Leida, Carmen; Terol, Javier; Martí, Gracia; Agustí, Manuel; Llácer, Gerardo; Badenes, María Luisa; Ríos, Gabino
A Molecular Timetable for Apical Bud Formation and Dormancy Induction in Poplar
The growth of perennial plants in the temperate zone alternates with periods of dormancy that are typically initiated during bud development in autumn. In a systems biology approach to unravel the underlying molecular program of apical bud development in poplar (Populus tremula 3 Populus alba), combined transcript and metabolite profiling were applied to a high-resolution time course from short-day induction
Tom Ruttink; Matthias Arend; Kris Morreel; Veronique Storme; Stephane Rombauts; Jorg Fromm; Rishikesh P. Bhalerao; Wout Boerjan; A. Rohde
Dose and tissue-specific interaction of monoterpenes with the gibberellin-mediated release of potato tuber bud dormancy, sprout growth and induction of ?-amylases and ?-amylases
Gibberellins (GA) are involved in bud dormancy release in several species. We show here that GA-treatment released bud dormancy,\\u000a initiated bud sprouting and promoted sprout growth of excised potato tuber bud discs ('eyes'). Monoterpenes from peppermint\\u000a oil (PMO) and S-(+)-carvone (CAR) interact with the GA-mediated bud dormancy release in a hormesis-type response: low monoterpene concentrations\\u000a enhance dormancy release and the
Sonja RentzschDagmara; Dagmara Podzimska; Antje Voegele; Madeleine Imbeck; Kerstin Müller; Ada Linkies; Gerhard Leubner-Metzger
Light and temperature sensing and signaling in induction of bud dormancy in woody plants
In woody species cycling between growth and dormancy must be precisely synchronized with the seasonal climatic variations.\\u000a Cessation of apical growth, resulting from exposure to short photoperiod (SD) and altered light quality, is gating the chain\\u000a of events resulting in bud dormancy and cold hardiness. The relative importance of these light parameters, sensed by phytochromes\\u000a and possibly a blue light
Jorunn E. Olsen
Light and temperature sensing and signaling in induction of bud dormancy in woody plants.
In woody species cycling between growth and dormancy must be precisely synchronized with the seasonal climatic variations. Cessation of apical growth, resulting from exposure to short photoperiod (SD) and altered light quality, is gating the chain of events resulting in bud dormancy and cold hardiness. The relative importance of these light parameters, sensed by phytochromes and possibly a blue light receptor, varies with latitude. Early in SD, changes in expression of light signaling components dominate. In Populus active shoot elongation is linked to high expression of FLOWERING LOCUS T (FT) resulting from coincidence of high levels of CONSTANS and light at the end of days longer than a critical one. In Picea, PaFT4 expression increases substantially in response to SD. Thus, in contrast to Populus-FT, PaFT4 appears to function in inhibition of shoot elongation or promotion of growth cessation. Accordingly, different FT-genes appear to have opposite effects in photoperiodic control of shoot elongation. Reduction in gibberellin under SD is involved in control of growth cessation and bud formation, but not further dormancy development. Coinciding with formation of a closed bud, abscisic acid activity increases and cell-proliferation genes are down-regulated. When dormancy is established very few changes in gene expression occur. Thus, maintenance of dormancy is not dependent on comprehensive transcriptional regulation. In some species low temperature induces growth cessation and dormancy, in others temperature affects photoperiod requirement. The temperature under SD affects both the rate of growth cessation, bud formation and depth of dormancy. As yet, information on the molecular basis of these responses to temperature is scarce. PMID:20213333
Olsen, Jorunn E
Bud dormancy and vegetative growth in Salix polaris as affected by temperature and photoperiod
Vegetative growth of two ecotypes (lat. 78° 15'N and 69°37'N) of Salix polaris L. was studied in phytotron experiments. Dormancy of the winter buds was broken by chilling at 0.5°C for 14 to 42 days. Chilling requirement increased with decreasing growth temperature. The optimum temperature for bud break and shoot growth was about 15°C for both ecotypes. Cessation of apical
Espen Paus; Jarle Nilsen; Olavi Junttila
Differential expression of proteins associated with seasonal bud dormancy at four critical stages in Japanese apricot.
Dormancy is of great significance in the growth and development of deciduous fruit trees. We used a combination of two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionisation time of flight/time of flight mass spectrometry (MALDI-TOF/TOF MS) to identify the differentially expressed proteome of Japanese apricot flower buds at four critical stages, from paradormancy before leaf fall to dormancy release. More than 400 highly reproducible protein spots (P < 0.05) were detected: 34 protein spots showed a greater than twofold difference in expression values, of which 32 protein spots were confidently identified from databases. Identified proteins were classified into six functional categories: stress response and defence (11), energy metabolism (ten), protein metabolism (five), cell structure (three), transcription (one) and unclassified (two). The glyoxalase I homologue could help Japanese apricot survival under various abiotic and biotic stresses, greatly contributing to its dormancy. Enolase, thioredoxin family proteins and triose phosphate isomerase provide adequate energy to complete consecutive dormancy release and bud break in Japanese apricot. Cinnamyl alcohol dehydrogenase 9 and arginase enhance the resilience of plants, enabling them to complete dormancy safely. Analysis of functions of identified proteins and related metabolic pathways will increase our knowledge of dormancy in woody plants. PMID:22672637
Zhuang, W-B; Shi, T; Gao, Z-H; Zhang, Z; Zhang, J-Y
Reproductive meristems and embryos display dormancy mechanisms in specialized structures named respectively buds and seeds that arrest the growth of perennial plants until environmental conditions are optimal for survival. Dormancy shows common physiological features in buds and seeds. A genotype-specific period of chilling is usually required to release dormancy by molecular mechanisms that are still poorly understood. In order to find common transcriptional pathways associated to dormancy release, we analyzed the chilling-dependent expression in embryos of certain genes that were previously found related to dormancy in flower buds of peach. We propose the presence of short and long-term dormancy events affecting respectively the germination rate and seedling development by independent mechanisms. Short periods of chilling seem to improve germination in an abscisic acid-dependent manner, whereas the positive effect of longer cold treatments on physiological dwarfing coincides with the accumulation of phenylpropanoids in the seed.
Arbona, Vicent; Gomez-Cadenas, Aurelio; Llacer, Gerardo; Badenes, Maria Luisa; Rios, Gabino
Slash pine bud dormancy as affected by lifting date and root wrenching in the nursery.
Bud dormancy of root wrenched and unwrenched slash pine (Pinus elliottii Engelm.) seedlings growing in a forest nursery was measured on five lifting dates. Determination of bud dormancy was based on days to budbreak (DBB) under optimal growing conditions, mitotic activity in the apical meristem, chilling hours accumulated, and bud morphology. Based on DBB, seedlings were most dormant at Lift 2 on November 24 after exposure to 189 hours below 10 degrees C and 93 hours below 6.7 degrees C. Mitotic activity in the apical meristem was at its lowest 23 days later at Lift 3, possibly indicating the period when seedlings are most resistant to transplanting stresses. Multiple wrenching resulted in a slight shift in the dormancy cycle as wrenched seedlings set bud sooner in the nursery and broke bud sooner at the planting site in the spring than control seedlings. This implies that wrenched seedlings can be successfully lifted from the nursery earlier and will initiate spring shoot growth earlier than control seedlings. PMID:14972840
Kainer, K A; Duryea, M L; White, T L; Johnson, J D
Transcriptomic analysis of 'Suli' pear (Pyrus pyrifolia white pear group) buds during the dormancy by RNA-Seq
Background Bud dormancy is a critical developmental process that allows perennial plants to survive unfavorable environmental conditions. Pear is one of the most important deciduous fruit trees in the world, but the mechanisms regulating bud dormancy in this species are unknown. Because genomic information for pear is currently unavailable, transcriptome and digital gene expression data for this species would be valuable resources to better understand the molecular and biological mechanisms regulating its bud dormancy. Results We performed de novo transcriptome assembly and digital gene expression (DGE) profiling analyses of 'Suli' pear (Pyrus pyrifolia white pear group) using the Illumina RNA-seq system. RNA-Seq generated approximately 100 M high-quality reads that were assembled into 69,393 unigenes (mean length?=?853 bp), including 14,531 clusters and 34,194 singletons. A total of 51,448 (74.1%) unigenes were annotated using public protein databases with a cut-off E-value above 10-5. We mainly compared gene expression levels at four time-points during bud dormancy. Between Nov. 15 and Dec. 15, Dec. 15 and Jan. 15, and Jan. 15 and Feb. 15, 1,978, 1,024, and 3,468 genes were differentially expressed, respectively. Hierarchical clustering analysis arranged 190 significantly differentially-expressed genes into seven groups. Seven genes were randomly selected to confirm their expression levels using quantitative real-time PCR. Conclusions The new transcriptomes offer comprehensive sequence and DGE profiling data for a dynamic view of transcriptomic variation during bud dormancy in pear. These data provided a basis for future studies of metabolism during bud dormancy in non-model but economically-important perennial species.
EARLY BUD-BREAK 1 (EBB1) is a regulator of release from seasonal dormancy in poplar trees.
Trees from temperate latitudes transition between growth and dormancy to survive dehydration and freezing stress during winter months. We used activation tagging to isolate a dominant mutation affecting release from dormancy and identified the corresponding gene EARLY BUD-BREAK 1 (EBB1). We demonstrate through positioning of the tag, expression analysis, and retransformation experiments that EBB1 encodes a putative APETALA2/Ethylene responsive factor transcription factor. Transgenic up-regulation of the gene caused early bud-flush, whereas down-regulation delayed bud-break. Native EBB1 expression was highest in actively growing apices, undetectable during the dormancy period, but rapidly increased before bud-break. The EBB1 transcript was localized in the L1/L2 layers of the shoot meristem and leaf primordia. EBB1-overexpressing transgenic plants displayed enlarged shoot meristems, open and poorly differentiated buds, and a higher rate of cell division in the apex. Transcriptome analyses of the EBB1 transgenics identified 971 differentially expressed genes whose expression correlated with the EBB1 expression changes in the transgenic plants. Promoter analysis among the differentially expressed genes for the presence of a canonical EBB1-binding site identified 65 putative target genes, indicative of a broad regulatory context of EBB1 function. Our results suggest that EBB1 has a major and integrative role in reactivation of meristem activity after winter dormancy. PMID:24951507
Yordanov, Yordan S; Ma, Cathleen; Strauss, Steven H; Busov, Victor B
Comparative proteomic and transcriptomic approaches to address the active role of GA4 in Japanese apricot flower bud dormancy release
Hormones are closely associated with dormancy in deciduous fruit trees, and gibberellins (GAs) are known to be particularly important. In this study, we observed that GA4 treatment led to earlier bud break in Japanese apricot. To understand better the promoting effect of GA4 on the dormancy release of Japanese apricot flower buds, proteomic and transcriptomic approaches were used to analyse the mechanisms of dormancy release following GA4 treatment, based on two-dimensional gel electrophoresis (2-DE) and digital gene expression (DGE) profiling, respectively. More than 600 highly reproducible protein spots (P<0.05) were detected and, following GA4 treatment, 38 protein spots showed more than a 2-fold difference in expression, and 32 protein spots were confidently identified according to the databases. Compared with water treatment, many proteins that were associated with energy metabolism and oxidation–reduction showed significant changes after GA4 treatment, which might promote dormancy release. We observed that genes at the mRNA level associated with energy metabolism and oxidation–reduction also played an important role in this process. Analysis of the functions of the identified proteins and genes and the related metabolic pathways would provide a comprehensive proteomic and transcriptomic view of the coordination of dormancy release after GA4 treatment in Japanese apricot flower buds.
Zhuang, Weibing; Gao, Zhihong; Zhang, Zhen
Bud burst timing in Picea abies seedlings as affected by temperature during dormancy induction and mild spells during chilling.
In trees adapted to cold climates, conditions during autumn and winter may influence the subsequent timing of bud burst and hence tree survival during early spring frosts. We tested the effects of two temperatures during dormancy induction and mild spells (MS) during chilling on the timing of bud burst in three Picea abies (L.) Karst. provenances (58-66 degrees N). One-year-old seedlings were induced to become dormant at temperatures of 12 or 21 degrees C applied during 9 weeks of short days (12-h photoperiod). The seedlings were then moved to cold storage and given either continuous chilling at 0.7 degrees C (control), or chilling interrupted by one 14-day MS at either 8 or 12 degrees C. Interruptions with MS were staggered throughout the 175-day chilling period, resulting in 10 MS differing in date of onset. Subsets of seedlings were moved to forcing conditions (12-h photoperiod, 12 degrees C) throughout the chilling period, to assess dormancy status at different timings of the MS treatment. Finally, after 175 days of chilling, timing of bud burst was assessed in a 24-h photoperiod at 12 degrees C (control and MS-treated seedlings). The MS treatment did not significantly affect days to bud burst when given early (after 7-35 chilling days). When MS was given after 49 chilling days or later, the seedlings burst bud earlier than the controls, and the difference increased with increasing length of the chilling period given before the MS. The 12 degrees C MS treatment was more effective than the 8 degrees C MS treatment, and the difference remained constant after the seedlings had received 66 or more chilling days before the MS treatment was applied. In all provenances, a constant temperature of 21 degrees C during dormancy induction resulted in more dormant seedlings (delayed bud burst) than a constant temperature of 12 degrees C, but this did not delay the response to the MS treatment. PMID:19203964
Granhus, Aksel; Flřistad, Inger Sundheim; Sřgaard, Gunnhild
Seasonal progression of bud dormancy in apricot (Prunus armeniaca L.) in a Mediterranean climate: A single-node cutting approach
The progression of the dormancy of apricot (Prunus armeniaca L.) vegetative and reproductive buds in the summer–winter period (June–March) was analysed with the single-node cutting method during two consecutive years in a Mediterranean climate. The progression of the mean time to budbreak (MTB) was studied. Low MTB values were obtained, which show endodormancy intensity under climatic conditions in the South
J. A. Campoy; D. Ruiz; J. Egea
Conservation and divergence of four kiwifruit SVP-like MADS-box genes suggest distinct roles in kiwifruit bud dormancy and flowering
MADS-box genes similar to Arabidopsis SHORT VEGETATIVE PHASE (SVP) have been implicated in the regulation of flowering in annual species and bud dormancy in perennial species. Kiwifruit (Actinidia spp.) are woody perennial vines where bud dormancy and out-growth affect flower development. To determine the role of SVP-like genes in dormancy and flowering of kiwifruit, four MADS-box genes with homology to Arabidopsis SVP, designated SVP1, SVP2, SVP3, and SVP4, have been identified and analysed in kiwifruit and functionally characterized in Arabidopsis. Phylogenetic analysis indicate that these genes fall into different sub-clades within the SVP-like gene group, suggesting distinct functions. Expression was generally confined to vegetative tissues, and increased transcript accumulation in shoot buds over the winter period suggests a role for these genes in bud dormancy. Down-regulation before flower differentiation indicate possible roles as floral repressors. Over-expression and complementation studies in Arabidopsis resulted in a range of floral reversion phenotypes arising from interactions with Arabidopsis MADS-box proteins, but only SVP1 and SVP3 were able to complement the svp mutant. These results suggest that the kiwifruit SVP-like genes may have distinct roles during bud dormancy and flowering.
Wu, Rong-Mei; Walton, Eric F.; Richardson, Annette C.; Wood, Marion; Hellens, Roger P.; Varkonyi-Gasic, Erika
Gibberellic Acid and Ethephon Alter Potato Minituber Bud Dormancy and Improve Seed Tuber Yield
While greenhouse production of minitubers has markedly improved production of disease free seed, minituber dormancy can be\\u000a an issue. This study tested application of abscisic acid (ABA), ethylene (E), gibberellic acid (GA) and the combination of\\u000a E+GA on release of dormancy in potato minitubers, sprout development, and subsequent effects on field plant growth and yield\\u000a of seed tubers. Cultivars were
Oktay Külen; Cecil Stushnoff; Robert D. Davidson; David G. Holm
Dose- and tissue-specific interaction of monoterpenes with the gibberellin-mediated release of potato tuber bud dormancy, sprout growth and induction of ?-amylases and ?-amylases.
Gibberellins (GA) are involved in bud dormancy release in several species. We show here that GA-treatment released bud dormancy, initiated bud sprouting and promoted sprout growth of excised potato tuber bud discs ('eyes'). Monoterpenes from peppermint oil (PMO) and S-(+)-carvone (CAR) interact with the GA-mediated bud dormancy release in a hormesis-type response: low monoterpene concentrations enhance dormancy release and the initiation of bud sprouting, whereas high concentrations inhibit it. PMO and CAR did, however, not affect sprout growth rate after its onset. We further show that GA-induced dormancy release is associated with tissue-specific regulation of ?- and ?-amylases. Molecular phylogenetic analysis shows that potato ?-amylases cluster into two distinct groups: ?-AMY1 and ?-AMY2. GA-treatment induced transcript accumulation of members of both ?-amylase groups, as well as ?- and ?-amylase enzyme activity in sprout and 'sub-eye' tissues. In sprouts, CAR interacts with the GA-mediated accumulation of ?-amylase transcripts in an ?-AMY2-specific and dose-dependent manner. Low CAR concentrations enhance the accumulation of ?-AMY2-type ?-amylase transcripts, but do not affect the ?-AMY1-type transcripts. Low CAR concentrations also enhance the accumulation of ?- and ?-amylase enzyme activity in sprouts, but not in 'sub-eye' tissues. In contrast, high CAR concentrations have no appreciable effect in sprouts on the enzyme activities and the ?-amylase transcript abundances of either group. The dose-dependent effects on the enzyme activities and the ?-AMY2-type ?-amylase transcripts in sprouts are specific for CAR but not for PMO. Different monoterpenes therefore may have specific targets for their interaction with hormone signalling pathways. PMID:21858448
Rentzsch, Sonja; Podzimska, Dagmara; Voegele, Antje; Imbeck, Madeleine; Müller, Kerstin; Linkies, Ada; Leubner-Metzger, Gerhard
ptr-MIR169 is a posttranscriptional repressor of PtrHAP2 during vegetative bud dormancy period of aspen (Populus tremuloides) trees
SciTech Connect
Highlights: ? We show a novel microRNA-mediated mechanism for control of bud dormancy in trees. ? ptr-MIR169a and PtrHAP2–5 gene showed inverse expression during dormancy period. ? The PtrHAP2–5 decline in abundance correlated with high ptr-MIR169a levels. ? PtrHAP2–5 cleavage occurred at the miR169 site during PtrHAP2–5 transcript decline. ? Our results show that miR169 attenuates PtrHAP2–5 transcript during dormancy. -- Abstract: Dormancy is a mechanism evolved in woody perennial plants to survive the winter freezing and dehydration stress via temporary suspension of growth. We have identified two aspen microRNAs (ptr-MIR169a and ptr-MIR169h) which were highly and specifically expressed in dormant floral and vegetative buds. ptr-MIR169a and its target gene PtrHAP2–5 showed inverse expression patterns during the dormancy period. ptr-MIR169a transcript steadily increased through the first half of the dormancy period and gradually declined with the approach of active growing season. PtrHAP2–5 abundance was higher in the beginning of the dormancy period but rapidly declined thereafter. The decline of PtrHAP2–5 correlated with the high levels of ptr-MIR169a accumulation, suggesting miR169-mediated attenuation of the target PtrHAP2–5 transcript. We experimentally verified the cleavage of PtrHAP2–5 at the predicted miR169a site at the time when PtrHAP2–5 transcript decline was observed. HAP2 is a subunit of a nuclear transcription factor Y (NF-Y) complex consisting of two other units, HAP3 and HAP5. Using digital expression profiling we show that poplar HAP2 and HAP5 are preferentially detected in dormant tissues. Our study shows that microRNAs play a significant and as of yet unknown and unstudied role in regulating the timing of bud dormancy in trees.
Potkar, Rewati; Recla, Jill [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)] [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States); Busov, Victor, E-mail: email@example.com [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)] [School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931 (United States)
BRANCHED1 promotes axillary bud dormancy in response to shade in Arabidopsis.
Plants interpret a decrease in the red to far-red light ratio (R:FR) as a sign of impending shading by neighboring vegetation. This triggers a set of developmental responses known as shade avoidance syndrome. One of these responses is reduced branching through suppression of axillary bud outgrowth. The Arabidopsis thaliana gene BRANCHED1 (BRC1), expressed in axillary buds, is required for branch suppression in response to shade. Unlike wild-type plants, brc1 mutants develop several branches after a shade treatment. BRC1 transcription is positively regulated 4 h after exposure to low R:FR. Consistently, BRC1 is negatively regulated by phytochrome B. Transcriptional profiling of wild-type and brc1 buds of plants treated with simulated shade has revealed groups of genes whose mRNA levels are dependent on BRC1, among them a set of upregulated abscisic acid response genes and two networks of cell cycle- and ribosome-related downregulated genes. The downregulated genes have promoters enriched in TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) binding sites, suggesting that they could be transcriptionally regulated by TCP factors. Some of these genes respond to BRC1 in seedlings and buds, supporting their close relationship with BRC1 activity. This response may allow the rapid adaptation of plants to fluctuations in the ratio of R:FR light. PMID:23524661
González-Grandío, Eduardo; Poza-Carrión, César; Sorzano, Carlos Oscar S; Cubas, Pilar
Dormancy in Peach (Prunus persica L.) Flower Buds : I. Floral Morphogenesis and Endogenous Gibberellins at the End of the Dormancy Period.
Flower buds of peach (Prunus persica L.) trees, cv Novedad de Cordoba (Argentina), were collected near the end of the dormant period and immediately before anthesis. After removal of scale leaves, morphological observations of representative buds, made on transverse and longitudinal microtome sections, showed that all verticils making up the flower are present in an undifferentiated form during the dormant period (June). Flower buds collected at the end of dormant period (August) showed additional growth and differentiation, at which time formation of two ovules was beginning in the unicarpelar gynoecium. Dehiscence of anthers had not yet occurred 10 days before full bloom, and the ovules were still developing. Free endogenous gibberellin (GA)-like substances were quantified by bioassay (Tan-ginbozu dwarf rice microdrop) after SiO(2) partition column chromatography, reversed phase C18-high performance liquid chromatography, and finally Nucleosil [N(CH(3))(2)]high performance liquid chromatography. Bioactive fractions were then subjected to capillary gas chromatography-mass spectrometry-selected ion monitoring (GC-MS-SIM). Gibberellins A(1), A(3), and A(8) were tentatively identified in peach flower buds using GC-SIM and Kovat's retention indices, and relative amounts approximated by GC-SIM (2:8:6 for GA(1), GA(3), and GA(8), respectively). The highest concentration (330 nanograms per gram dry weight) of free GA(1)/GA(3) was found in dormant buds (June) and diminished thereafter. The concentration free of GA(1)/GA(3) did not increase immediately prior to bud break. However, high GA(1)/GA(3) concentrations occurred during stages where rate of growth and cellular differentiation of (mainly fertile) verticils can be influenced. PMID:16667435
Luna, V; Lorenzo, E; Reinoso, H; Tordable, M C; Abdala, G; Pharis, R P; Bottini, R
A rapid transcriptional activation is induced by the dormancy-breaking chemical hydrogen cyanamide in kiwifruit (Actinidia deliciosa) buds
Budbreak in kiwifruit (Actinidia deliciosa) can be poor in locations that have warm winters with insufficient winter chilling. Kiwifruit vines are often treated with the dormancy-breaking chemical hydrogen cyanamide (HC) to increase and synchronize budbreak. This treatment also offers a tool to understand the processes involved in budbreak. A genomics approach is presented here to increase our understanding of budbreak in kiwifruit. Most genes identified following HC application appear to be associated with responses to stress, but a number of genes appear to be associated with the reactivation of growth. Three patterns of gene expression were identified: Profile 1, an HC-induced transient activation; Profile 2, an HC-induced transient activation followed by a growth-related activation; and Profile 3, HC- and growth-repressed. One group of genes that was rapidly up-regulated in response to HC was the glutathione S-transferase (GST) class of genes, which have been associated with stress and signalling. Previous budbreak studies, in three other species, also report up-regulated GST expression. Phylogenetic analysis of these GSTs showed that they clustered into two sub-clades, suggesting a strong correlation between their expression and budbreak across species.
Walton, Eric F.; Wu, Rong-Mei; Richardson, Annette C.; Davy, Marcus; Hellens, Roger P.; Thodey, Kate; Janssen, Bart J.; Gleave, Andrew P.; Rae, Georgina M.; Wood, Marion; Schaffer, Robert J.
Chilling of Dormant Buds Hyperinduces FLOWERING LOCUS T and Recruits GA-Inducible 1,3-?-Glucanases to Reopen Signal Conduits and Release Dormancy in Populus[W][OA
In trees, production of intercellular signals and accessibility of signal conduits jointly govern dormancy cycling at the shoot apex. We identified 10 putative cell wall 1,3-?-glucanase genes (glucan hydrolase family 17 [GH17]) in Populus that could turn over 1,3-?-glucan (callose) at pores and plasmodesmata (PD) and investigated their regulation in relation to FT and CENL1 expression. The 10 genes encode orthologs of Arabidopsis thaliana BG_ppap, a PD-associated glycosylphosphatidylinositol (GPI) lipid-anchored protein, the Arabidopsis PD callose binding protein PDCB, and a birch (Betula pendula) putative lipid body (LB) protein. We found that these genes were differentially regulated by photoperiod, by chilling (5°C), and by feeding of gibberellins GA3 and GA4. GA3 feeding upregulated all LB-associated GH17s, whereas GA4 upregulated most GH17s with a GPI anchor and/or callose binding motif, but only GA4 induced true bud burst. Chilling upregulated a number of GA biosynthesis and signaling genes as well as FT, but not CENL1, while the reverse was true for both GA3 and GA4. Collectively, the results suggest a model for dormancy release in which chilling induces FT and both GPI lipid-anchored and GA3-inducible GH17s to reopen signaling conduits in the embryonic shoot. When temperatures rise, the reopened conduits enable movement of FT and CENL1 to their targets, where they drive bud burst, shoot elongation, and morphogenesis.
Rinne, Paivi L.H.; Welling, Annikki; Vahala, Jorma; Ripel, Linda; Ruonala, Raili; Kangasjarvi, Jaakko; van der Schoot, Christiaan
Phylogenetic analysis and molecular evolution of the dormancy associated MADS-box genes from peach
BACKGROUND: Dormancy associated MADS-box (DAM) genes are candidates for the regulation of growth cessation and terminal bud formation in peach. These genes are not expressed in the peach mutant evergrowing, which fails to cease growth and enter dormancy under dormancy-inducing conditions. We analyzed the phylogenetic relationships among and the rates and patterns of molecular evolution within DAM genes in the
Sergio Jiménez; Amy L Lawton-Rauh; Gregory L Reighard; Albert G Abbott; Douglas G Bielenberg
Label-free quantitative proteomics analysis of dormant terminal buds of poplar.
Induction and break of bud dormancy are important features for perennial plants surviving extreme seasonal variations in climate. However, the molecular mechanism of the dormancy regulation, still remain poorly understood. To better understand the molecular basis of poplar bud dormancy, we used a label-free quantitative proteomics method based on nanoscale ultra performance liquid chromatography-ESI-MS(E) for investigation of differential protein expression during dormancy induction, dormancy, and dormancy break in apical buds of poplar (Populus simonii × P. nigra). Among these identified over 300 proteins during poplar bud dormancy, there are 74 significantly altered proteins, most of which involved in carbohydrate metabolism (22 %), redox regulation (19 %), amino acid transport and metabolism (10 %), and stress response (8 %). Thirty-one of these proteins were up-regulated, five were down-regulated during three phase, and thirty-eight were expressed specifically under different conditions. Pathway analysis suggests that there are still the presence of various physiological activities and a particular influence on photosynthesis and energy metabolism during poplar bud dormancy. Differential expression patterns were identified for key enzymes involved in major metabolic pathways such as glycolysis and the pentose phosphate pathway, thus manifesting the interplay of intricate molecular events in energy generation for new protein synthesis in the dormant buds. Furthermore, there are significant changes present in redox regulation and defense response proteins, for instance in peroxidase and ascorbate peroxidase. Overall, this study provides a better understanding of the possible regulation mechanisms during poplar bud dormancy. PMID:23677710
Ning, De-Li; Liu, Chang-Cai; Liu, Jin-Wen; Shen, Zhuo; Chen, Su; Liu, Feng; Wang, Bai-Chen; Yang, Chuan-Ping
The minimum temperature for budburst in Betula depends on the state of dormancy.
Vegis has put forward the theory that the range of growth-promoting temperatures changes during the induction and the release of dormancy. We have tested the response of buds of Betula pubescens Ehrh. and B. pendula Roth. on temperature during the induction and release of dormancy. Betula seedlings were exposed to dormancy-inducing high-temperature and short-day conditions and subsequently to dormancy-releasing chilling conditions in darkness. To monitor the dormancy status of the seedlings, subsets of them were transferred to five forcing temperatures and their budburst was observed. The results show that the expression of dormancy was temperature dependent, so that the minimum temperature for 100% budburst rose during the induction and dropped during the release of dormancy. These responses may explain previous contradictions between experimental and modelling studies, but that needs to be verified with more extensive experiments, some of which are identified in this study. The results provide further evidence for the concept of gradual change in bud dormancy. They also suggest that global change studies modelling budburst phenology should address the changing expression of bud dormancy. PMID:22391009
Junttila, Olavi; Hänninen, Heikki
Photoperiod and temperature responses of bud swelling and bud burst in four temperate forest tree species.
Spring phenology of temperate forest trees is optimized to maximize the length of the growing season while minimizing the risk of freezing damage. The release from winter dormancy is environmentally mediated by species-specific responses to temperature and photoperiod. We investigated the response of early spring phenology to temperature and photoperiod at different stages of dormancy release in cuttings from four temperate tree species in controlled environments. By tracking bud development, we were able to identify the onset of bud swelling and bud growth in Acer pseudoplatanus L., Fagus sylvatica L., Quercus petraea (Mattuschka) Liebl. and Picea abies (L.) H. Karst. At a given early stage of dormancy release, the onset and duration of the bud swelling prior to bud burst are driven by concurrent temperature and photoperiod, while the maximum growth rate is temperature dependent only, except for Fagus, where long photoperiods also increased bud growth rates. Similarly, the later bud burst was controlled by temperature and photoperiod (in the photoperiod sensitive species Fagus, Quercus and Picea). We conclude that photoperiod is involved in the release of dormancy during the ecodormancy phase and may influence bud burst in trees that have experienced sufficient chilling. This study explored and documented the early bud swelling period that precedes and defines later phenological stages such as canopy greening in conventional phenological works. It is the early bud growth resumption that needs to be understood in order to arrive at a causal interpretation and modelling of tree phenology at a large scale. Classic spring phenology events mark visible endpoints of a cascade of processes as evidenced here. PMID:24713858
Basler, David; Körner, Christian
Dormancy in Plant Seeds
\\u000a Seed dormancy has been studied intensely over the past decades and, at present, knowledge of this plant trait is at the forefront\\u000a of plant biology. The main model species is Arabidopsis thaliana, an annual weed, possessing nondeep physiological dormancy. This overview presents the state-of-the-art of seed dormancy\\u000a research, focusing mainly on physiological and molecular-genetic aspects in this species. It has
Henk W. M. Hilhorst; William E. Finch-Savage; Julia Buitink; William Bolingue; Gerhard Leubner-Metzger
Molecular Aspects of Seed Dormancy
Seed dormancy provides a mechanism for plants to delay germina- tion until conditions are optimal for survival of the next generation. Dormancy release is regulated by a combination of environmental and endogenous signals with both synergistic and competing effects. Molecular studies of dormancy have correlated changes in transcrip- tomes, proteomes, and hormone levels with dormancy states ranging from deep primary
Ruth Finkelstein; Wendy Reeves; Tohru Ariizumi; Camille Steber
Seed Dormancy and Germination
Seed dormancy allows seeds to overcome periods that are unfavourable for seedling established and is therefore important for plant ecology and agriculture. Several processes are known to be involved in the induction of dormancy and in the switch from the dormant to the germinating state. The role of plant hormones, the different tissues and genes involved, including newly identified genes in dormancy and germination are described in this chapter, as well as the use transcriptome, proteome and metabolome analyses to study these mechanistically not well understood processes.
Bentsink, Leonie; Koornneef, Maarten
Climatic control of bud burst in young seedlings of nine provenances of Norway spruce.
Detailed knowledge of temperature effects on the timing of dormancy development and bud burst will help evaluate the impacts of climate change on forest trees. We tested the effects of temperature applied during short-day treatment, duration of short-day treatment, duration of chilling and light regime applied during forcing on the timing of bud burst in 1- and 2-year-old seedlings of nine provenances of Norway spruce (Picea abies (L.) Karst.). High temperature during dormancy induction, little or no chilling and low temperature during forcing all delayed dormancy release but did not prevent bud burst or growth onset provided the seedlings were forced under long-day conditions. Without chilling, bud burst occurred in about 20% of seedlings kept in short days at 12 degrees C, indicating that young Norway spruce seedlings do not exhibit true bud dormancy. Chilling hastened bud burst and removed the long photoperiod requirement, but the effect of high temperature applied during dormancy induction was observed even after prolonged chilling. Extension of the short-day treatment from 4 to 8 or 12 weeks hastened bud burst. The effect of treatments applied during dormancy development was larger than that of provenance; in some cases no provenance effect was detected, but in 1-year-old seedlings, time to bud burst decreased linearly with increasing latitude of origin. Differences among provenances were complicated by different responses of some origins to light conditions under long-day forcing. In conclusion, timing of bud burst in Norway spruce seedlings is significantly affected by temperature during bud set, and these effects are modified by chilling and environmental conditions during forcing. PMID:18055441
Sřgaard, Gunnhild; Johnsen, Oystein; Nilsen, Jarle; Junttila, Olavi
Quantitative trait loci and candidate gene mapping of bud set and bud flush in populus.
The genetic control of bud phenology in hybrid poplar was studied by mapping quantitative trait loci (QTL) affecting the timing of autumn bud set and spring bud flush. The founders of the mapping pedigree were collected from widely separated latitudes to maximize segregating variation for dormancy-related traits in the F(2) generation-the female Populus trichocarpa parent is from Washington State (48 degrees N) and the male P. deltoides parent is from Texas (31 degrees N). Bud set and bud flush timing were measured on the F(2) generation in a replicated clonal field trial. Using a linkage map constructed of AFLP and microsatellite markers, three QTL controlling bud set and six QTL controlling bud flush were detected. Additionally, five candidate genes believed to be involved in perception of photoperiod (PHYB1, PHYB2) or transduction of abscisic acid response signals (ABI1B, ABI1D, and ABI3) were placed on the QTL map. PHYB2 and ABI1B were found to be coincident with QTL affecting bud set and bud flush.
Frewen, B E; Chen, T H; Howe, G T; Davis, J; Rohde, A; Boerjan, W; Bradshaw, H D
Genes associated with the end of dormancy in grapes.
A grape bud EST library was constructed and 4270 ESTs sequenced. The library clones were arrayed for the purpose of investigating the level of gene expression over time, particularly leading up to the buds' release from dormancy. The arrays were hybridized with P(33)-labeled probes produced from samples of buds collected at weekly intervals. These probes covered the time from 9 weeks prior to bud burst until just after the emergence of the shoots. Expression patterns from these genes have been examined. It was found that 74% of the genes in the data set were homologous to known proteins. Genes were then assigned to functional categories according to their primary BLAST match. Of these 13% were involved with photosynthesis, 13% with disease resistance and defense, 5% energy, 12% metabolism, 20% protein production and processing, 25% cell structure and plant growth and the remaining 12% were unclassified The expression pattern of a selection of "candidate" genes retrieved from literature previously reporting an association with dormancy changes was assessed. On closer examination most of these genes relate to the oxidative processes and stress responses within the cell. The results of this study show that even in the dormant state, gene expression in the buds is high. PMID:14648239
Pacey-Miller, Toni; Scott, Kirsten; Ablett, Effie; Tingey, Scott; Ching, Ada; Henry, Robert
Dormancy of metastatic melanoma
Summary Metastatic dormancy of melanoma has not received sufficient attention, most likely because once detectable, metastasis is almost invariably fatal and, understandably, the focus has been on finding ways to prolong life of patients with overt recurrences. Nevertheless, analysis of the published clinical and experimental data on melanoma indicates that some aspect of melanoma biology imitate traits recently associated with dormancy in other solid cancers. Among them the ability of some melanomas to disseminate early during primary tumor progression and once disseminated, to remain undetected (dormant) for years. Comparison of cutaneous and uveal melanoma indicates that, in spite of being of the same origin, they differ profoundly in their clinical progression. Importantly for this discussion, between 40 and 50% of uveal melanoma remain undetected for longer than a decade, while less than 5% of cutaneous melanoma show this behavior. Both types of melanoma have activating oncogene mutations that provide autonomous pro-proliferative signals, yet the consensus is that those are not sufficient for tumor progression. If that is the case, it is possible to envision that signals from outside the tumor cell, (microenvironment) shape the fate of an individual disseminated cell, regardless of an oncogene mutation, to progress or to pause in a state of dormancy. To stimulate further debate and inquiry we describe here a few examples of potential signals that might modify the fate of disseminated cell and provide brief description of the current knowledge on dormancy in other cancers. Our hope is to convince the reader that disseminated melanoma cells do enter periods of prolonged dormancy and that finding ways to induce it, or to prolong it, might mean an extension of symptoms-free life for melanoma patients. Ultimately, understanding the biology of dormancy and the mechanisms of dormant cell survival, might allow for their specific targeting and elimination.
Ossowski, Liliana; Aguirre-Ghiso, Julio A.
Dormancy in breast cancer
Tumor dormancy describes a prolonged quiescent state in which tumor cells are present, but disease progression is not yet clinically apparent. Breast cancer is especially known for long asymptomatic periods, up to 25 years, with no evidence of the disease, followed by a relapse. Factors that determine the cell's decision to enter a dormant state and that control its duration remain unclear. In recent years, considerable progress has been made in understanding how tumor cells circulating in the blood interact and extravasate into secondary sites and which factors might determine whether these cells survive, remain dormant, or become macrometastases. The mechanisms of tumor cell dormancy are still not clear. Two different hypotheses are currently discussed: tumor cells persist either by completely withdrawing from the cell cycle or by continuing to proliferate at a slow rate that is counterbalanced by cell death. Because dormant disseminated tumor cells may be the founders of metastasis, one hypothesis is that dormant tumor cells, or at least a fraction of them, share stem cell-like characteristics that may be responsible for their long half-lives and their suggested resistance to standard chemotherapy. Therefore, knowledge of the biology of tumor cell dormancy may be the basis from which to develop innovative targeted therapies to control or eliminate this tumor cell fraction. In this review, we discuss biological mechanisms and clinical implications of tumor dormancy in breast cancer patients.
Banys, Malgorzata; Hartkopf, Andreas D; Krawczyk, Natalia; Kaiser, Tatjana; Meier-Stiegen, Franziska; Fehm, Tanja; Neubauer, Hans
Yield stability of peach germplasm differing in dormancy and blooming season in the Mexican subtropics
Peach cultivation in Mexico has recently extended to subtropical climates to reduce drought, but in many areas winter frosts are a strong limiting factor. Information about the behavior of a wide range of peach accessions during dormancy and bud-break was collected over a 4-year period in the most important peach growing region in the subtropical highlands of central Mexico where
S Pérez
Water impermeable seed dormancy
Viable seeds that do not imbibe water and thus fail to germinate in an apparently favorable environment are commonly termed\\u000a impermeable or hard seed. This physical, exogenous dormancy is especially common in species of the Fabaceae. The ecological\\u000a significance of hard seed includes the ability to rapidly recolonize burnt areas after fire and to withstand ingestion by\\u000a animals and birds.
M. Philip Rolston
Expression analysis of PpDAM5 and PpDAM6 during flower bud development in peach ( Prunus persica)
We previously reported transcript amounts of peach PpDAM5 and PpDAM6 (Prunus persica Dormancy-Associated MADS 5 and 6) were negatively correlated with endodormancy release of peach vegetative buds (Yamane et al., 2011). We here investigated PpDAM5 and PpDAM6 expressions in lateral flower buds of peach in relation to seasonal flower bud development by using peach cultivars differing in their chilling requirements,
Hisayo Yamane; Tomomi Ooka; Hiroaki Jotatsu; Ryuta Sasaki; Ryutaro Tao
Release of apical dominance in potato tuber is accompanied by programmed cell death in the apical bud meristem.
Potato (Solanum tuberosum) tuber, a swollen underground stem, is used as a model system for the study of dormancy release and sprouting. Natural dormancy release, at room temperature, is initiated by tuber apical bud meristem (TAB-meristem) sprouting characterized by apical dominance (AD). Dormancy is shortened by treatments such as bromoethane (BE), which mimics the phenotype of dormancy release in cold storage by inducing early sprouting of several buds simultaneously. We studied the mechanisms governing TAB-meristem dominance release. TAB-meristem decapitation resulted in the development of increasing numbers of axillary buds with time in storage, suggesting the need for autonomous dormancy release of each bud prior to control by the apical bud. Hallmarks of programmed cell death (PCD) were identified in the TAB-meristems during normal growth, and these were more extensive when AD was lost following either extended cold storage or BE treatment. Hallmarks included DNA fragmentation, induced gene expression of vacuolar processing enzyme1 (VPE1), and elevated VPE activity. VPE1 protein was semipurified from BE-treated apical buds, and its endogenous activity was fully inhibited by a cysteinyl aspartate-specific protease-1-specific inhibitor N-Acetyl-Tyr-Val-Ala-Asp-CHO (Ac-YVAD-CHO). Transmission electron microscopy further revealed PCD-related structural alterations in the TAB-meristem of BE-treated tubers: a knob-like body in the vacuole, development of cytoplasmic vesicles, and budding-like nuclear segmentations. Treatment of tubers with BE and then VPE inhibitor induced faster growth and recovered AD in detached and nondetached apical buds, respectively. We hypothesize that PCD occurrence is associated with the weakening of tuber AD, allowing early sprouting of mature lateral buds. PMID:22362870
Teper-Bamnolker, Paula; Buskila, Yossi; Lopesco, Yael; Ben-Dor, Shifra; Saad, Inbal; Holdengreber, Vered; Belausov, Eduard; Zemach, Hanita; Ori, Naomi; Lers, Amnon; Eshel, Dani
The Normalcy of Dormancy
All microorganisms are exposed to periodic stresses that inhibit growth. Many bacteria and fungi weather these periods by entering a hardy, non-replicating state, often termed quiescence or dormancy. When this occurs during an infection, the resulting slowly-growing pathogen is able to tolerate both immune insults and prolonged antibiotic exposure. While the stresses encountered in a free-living environment may differ from those imposed by host immunity, these growth-limiting conditions impose common pressures and many of the corresponding microbial responses appear to be universal. In this review, we discuss the common features of these growth-limited states, which suggest new approaches for treating chronic infections such as tuberculosis.
Rittershaus, Emily S. C.; Baek, Seung-hun; Sassetti, Christopher M.
The Effects of Dormancy Status on the Endogenous Contents and Biological Activities of Jasmonic Acid, N-(jasmonoyl)Isoleucine, and Tuberonic Acid in Potato Tubers
The effects of storage and dormancy progression on the endogenous contents and the growth-regulating activities of jasmonic\\u000a acid (JA), jasmonoyl-isoleucine (JA-Ile), and tuberonic acid (TA) were determined in potato (Solanum tuberosum L. cv. Russet Burbank) minitubers and seed tubers over several harvest\\/storage seasons. In apical discs (consisting of both\\u000a periderm and buds) isolated from minitubers undergoing natural dormancy progression, JA
Jeffrey C. Suttle; Linda L. Huckle; Edward C. Lulai
Sequencing and annotation of the evergrowing locus in peach [ Prunus persica (L.) Batsch] reveals a cluster of six MADS-box transcription factors as candidate genes for regulation of terminal bud formation
Buds are specialized structures that protect fragile meristematic regions during dormancy and are part of the mechanism that\\u000a plants use to survive unfavorable environmental conditions such as low temperature or dessication stress. The evergrowing (evg) mutant of peach [Prunus persica (L.) Batsch] does not form terminal vegetative buds in response to dormancy-inducing conditions such as short days and low\\u000a temperatures,
Douglas Gary Bielenberg; Zhigang Li; Tetyana Zhebentyayeva; Shenghua Fan; Gregory Lynn Reighard; Ralph Scorza; Albert Glenn Abbott
Catalase inhibition accelerates dormancy release and sprouting in potato (Solanum tuberosum L.) tubers
The involvement of hydrogen peroxide (H2O2) metabolism in dormancy release and sprouting of potato (Solanum tuberosum L.) tubers has been investigated using three complementary approaches. In the fi rst approach, the evolution of the sprouting kinetics, H2O2 content and antioxidant enzyme activities were examined during tuber storage. The most important changes occurred at the « bud\\/sprout » level. In particular,
Mohammed Bajji; Frédéric Gastiny
Characterization, expression and function of DORMANCY ASSOCIATED MADS-BOX genes from leafy spurge
DORMANCY ASSOCIATED MADS-BOX (DAM) genes are related to AGAMOUS-LIKE 24 and SHORT VEGETATIVE PHASE genes of arabidopsis and are differentially regulated coordinately with endodormancy induction and release in buds of several\\u000a perennial plant species. DAM genes were first shown to directly impact endodormancy in peach where a deletion of a series of DAM resulted in loss of endodormancy induction. We
David P. HorvathSibum; Sibum Sung; Donghwan Kim; Wun Chao; James Anderson
Nitric oxide reduces seed dormancy in Arabidopsis
Dormancy is a property of many mature seeds, and experimentation over the past century has identified numerous chemical treatments that will reduce seed dormancy. Nitrogen-containing compounds including nitrate, nitrite, and cyanide break seed dormancy in a range of species. Experiments are described here that were carried out to further our understanding of the mechanism whereby these and other compounds, such
Paul C. Bethke; Igor G. L. Libourel; Russell L. Jones
Detail of secondary entrance south of main entrance on east ...
Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey
Detail of secondary entrance south of main entrance on east elevation; camera facing west. - Mare Island Naval Shipyard, Mechanics Shop, Waterfront Avenue, west side between A Street & Third Street, Vallejo, Solano County, CA
Expressional regulation of PpDAM5 and PpDAM6, peach (Prunus persica) dormancy-associated MADS-box genes, by low temperature and dormancy-breaking reagent treatment
The present study investigated the expressional regulation of PpDAM5 and PpDAM6, two of the six peach (Prunus persica) dormancy-associated MADS-box genes, in relation to lateral bud endodormancy. PpDAM5 and PpDAM6 were originally identified as homologues of Arabidopsis SHORT VEGETATIVE PHASE/AGAMOUS-LIKE 24 identified in the EVERGROWING locus of peach. Furthermore, PpDAM5 and PpDAM6 have recently been suggested to be involved in terminal bud dormancy. In this study, seasonal expression analyses using leaves, stems, and lateral buds of high-chill and low-chill peaches in field conditions indicated that both genes were up-regulated during the endodormancy period and down-regulated with endodormancy release. Controlled environment experiments showed that the expression of both PpDAM5 and PpDAM6 were up-regulated by ambient cool temperatures in autumn, while they were down-regulated by the prolonged period of cold temperatures in winter. A negative correlation between expression levels of PpDAM5 and PpDAM6 and bud burst percentage was found in the prolonged cold temperature treatment. Application of the dormancy-breaking reagent cyanamide to endo/ecodormant lateral buds induced early bud break and down-regulation of PpDAM5 and PpDAM6 expression at the same time. These results collectively suggest that PpDAM5 and PpDAM6 may function in the chilling requirement of peach lateral buds through growth-inhibiting functions for bud break.
Yamane, Hisayo; Ooka, Tomomi; Jotatsu, Hiroaki; Hosaka, Yukari; Sasaki, Ryuta; Tao, Ryutaro
Expressional regulation of PpDAM5 and PpDAM6, peach (Prunus persica) dormancy-associated MADS-box genes, by low temperature and dormancy-breaking reagent treatment.
The present study investigated the expressional regulation of PpDAM5 and PpDAM6, two of the six peach (Prunus persica) dormancy-associated MADS-box genes, in relation to lateral bud endodormancy. PpDAM5 and PpDAM6 were originally identified as homologues of Arabidopsis SHORT VEGETATIVE PHASE/AGAMOUS-LIKE 24 identified in the EVERGROWING locus of peach. Furthermore, PpDAM5 and PpDAM6 have recently been suggested to be involved in terminal bud dormancy. In this study, seasonal expression analyses using leaves, stems, and lateral buds of high-chill and low-chill peaches in field conditions indicated that both genes were up-regulated during the endodormancy period and down-regulated with endodormancy release. Controlled environment experiments showed that the expression of both PpDAM5 and PpDAM6 were up-regulated by ambient cool temperatures in autumn, while they were down-regulated by the prolonged period of cold temperatures in winter. A negative correlation between expression levels of PpDAM5 and PpDAM6 and bud burst percentage was found in the prolonged cold temperature treatment. Application of the dormancy-breaking reagent cyanamide to endo/ecodormant lateral buds induced early bud break and down-regulation of PpDAM5 and PpDAM6 expression at the same time. These results collectively suggest that PpDAM5 and PpDAM6 may function in the chilling requirement of peach lateral buds through growth-inhibiting functions for bud break. PMID:21378115
Roles of Endoplasmic Reticulum Stress and Unfolded Protein Response Associated Genes in Seed Stratification and Bud Endodormancy during Chilling Accumulation in Prunus persica
Dormancy mechanisms in seeds and buds arrest growth until environmental conditions are optimal for development. A genotype-specific period of chilling is usually required to release dormancy, but the underlying molecular mechanisms are still not fully understood. To discover transcriptional pathways associated with dormancy release common to seed stratification and bud endodormancy, we explored the chilling-dependent expression of 11 genes involved in endoplasmic reticulum stress and the unfolded protein response signal pathways. We propose that endoplasmic reticulum stress and the unfolded protein response impact on seed as well as bud germination and development by chilling-dependent mechanisms. The emerging discovery of similarities between seed stratification and bud endodormancy status indicate that these two processes are probably regulated by common endoplasmic reticulum stress and unfolded protein response signalling pathways. Clarification of regulatory pathways common to both seed and bud dormancy may enhance understanding of the mechanisms underlying dormancy and breeding programs may benefit from earlier prediction of chilling requirements for uniform blooming of novel genotypes of deciduous fruit tree species.
Fu, Xi Ling; Xiao, Wei; Wang, Dong Ling; Chen, Min; Tan, Qiu Ping; Li, Ling; De Chen, Xiu; Gao, Dong Sheng
Terminal bud failure of black cottonwood (Populus trichocarpa) exposed to salt-laden winter storms.
At coastal sites, trees are exposed to marine aerosols that may cause foliar necrosis and shoot dieback, which can result in deformed crowns and contorted stems. A six-year study of leaf primordia in terminal buds of black cottonwood trees (Populus trichocarpa Torr. & Gray) on Heimaey Island off the south coast of Iceland was undertaken to elucidate the physiological events associated with salt-deposition-related bud failure. Leaf and bud lengths, dry mass, water content and chloride concentrations were monitored and related to four phenological stages: (1) bud set; (2) dormancy induction; (3) dormancy release; and (4) bud break. The trees set buds in July and shed their leaves by late September. Leaf primordia generally stopped growing by September 10 +/- 22 days and attained midwinter water content in late September. Leaf growth commenced in the terminal buds by March 2 +/- 16 days, but mean dates of bud swelling and bud break were April 29 +/- 19 and May 10 +/- 12 days. In summer and until November, chloride concentrations in leaf primordia were low, but increasing. Chloride concentrations remained stable from December to February, even though the dormant trees were exposed to large amounts of marine aerosols. In February and March, three events occurred more or less simultaneously: (1) leaf extension growth commenced; (2) chloride concentration surged in the leaf primordia; and (3) the leaf primordia began to hydrate. Following dormancy release, growth and hydration of leaf primordia were negatively related to chloride concentration in the leaf primordia, with inhibition of leaf growth, tissue hydration and chloride acquisition occurring at a chloride concentration threshold estimated at 7.3 mg Cl- g(-1) tissue water. Necrosis of leaf primordia was observed above 14 mg Cl- g(-1) tissue water. Growth and hydration of leaves at bud break in mid-May was explained by a three-parameter logistic model of chloride concentration in leaf primordia at the end of March. By mid-May, 90% of all buds remained non-necrotic, but only 56% the terminal buds had broken. Salt alone explained the observed growth suppression of leaf primordia in the buds and the resultant failure of terminal buds to break by mid-May. PMID:16585036
Jonsson, Thorbergur H
Release of Apical Dominance in Potato Tuber Is Accompanied by Programmed Cell Death in the Apical Bud Meristem[C][W
Potato (Solanum tuberosum) tuber, a swollen underground stem, is used as a model system for the study of dormancy release and sprouting. Natural dormancy release, at room temperature, is initiated by tuber apical bud meristem (TAB-meristem) sprouting characterized by apical dominance (AD). Dormancy is shortened by treatments such as bromoethane (BE), which mimics the phenotype of dormancy release in cold storage by inducing early sprouting of several buds simultaneously. We studied the mechanisms governing TAB-meristem dominance release. TAB-meristem decapitation resulted in the development of increasing numbers of axillary buds with time in storage, suggesting the need for autonomous dormancy release of each bud prior to control by the apical bud. Hallmarks of programmed cell death (PCD) were identified in the TAB-meristems during normal growth, and these were more extensive when AD was lost following either extended cold storage or BE treatment. Hallmarks included DNA fragmentation, induced gene expression of vacuolar processing enzyme1 (VPE1), and elevated VPE activity. VPE1 protein was semipurified from BE-treated apical buds, and its endogenous activity was fully inhibited by a cysteinyl aspartate-specific protease-1-specific inhibitor N-Acetyl-Tyr-Val-Ala-Asp-CHO (Ac-YVAD-CHO). Transmission electron microscopy further revealed PCD-related structural alterations in the TAB-meristem of BE-treated tubers: a knob-like body in the vacuole, development of cytoplasmic vesicles, and budding-like nuclear segmentations. Treatment of tubers with BE and then VPE inhibitor induced faster growth and recovered AD in detached and nondetached apical buds, respectively. We hypothesize that PCD occurrence is associated with the weakening of tuber AD, allowing early sprouting of mature lateral buds.
Differential floral development and gene expression in grapevines during long and short photoperiods suggests a role for floral genes in dormancy transitioning
Daylength is an important environmental cue for synchronizing growth, flowering, and dormancy with seasonality. As many floral\\u000a development genes are photoperiod regulated, it has been suggested that they could have a regulatory role in bud endodormancy.\\u000a Therefore, the influence of photoperiod was studied on inflorescence primordia differentiation and floral pathway related\\u000a gene expression during the development of overwintering buds in
Lekha Sreekantan; Kathy Mathiason; Jérôme Grimplet; Karen Schlauch; Julie A. Dickerson; Anne Y. Fennell
Dormancy-associated MADS genes from the EVG locus of peach [Prunus persica (L.) Batsch] have distinct seasonal and photoperiodic expression patterns
Mapping and sequencing of the non-dormant evg mutant in peach (Prunus persica (L.) Batsch) identified six tandem- arrayed DAM (dormancy-associated MADS-box) genes as candidates for regulating growth cessation and terminal bud formation. To narrow the list of candidate genes, an attempt was made to associate bud phenology with the seasonal and environmental patterns of expression of the candidates in wild-type
Zhigang Li; Gregory Lynn Reighard; Albert Glenn Abbott; Douglas Gary Bielenberg
Role of Abscisic Acid in Seed Dormancy
Seed dormancy is an adaptive trait that improves survival of the next generation by optimizing the distribution of germination\\u000a over time. The agricultural and forest industries rely on seeds that exhibit high rates of germination and vigorous, synchronous\\u000a growth after germination; hence dormancy is sometimes considered an undesirable trait. The forest industry encounters problems\\u000a with the pronounced dormancy of some
Allison R. Kermode
Summer Dormancy in Perennial Temperate Grasses
• Background and Aims Dormancy has been extensively studied in plants which experience severe winter conditions but much less so in perennial herbaceous plants that must survive summer drought. This paper reviews the current knowledge on summer dormancy in both native and cultivated perennial temperate grasses originating from the Mediterranean Basin, and presents a unified terminology to describe this trait. • Scope Under severe drought, it is difficult to separate the responses by which plants avoid and tolerate dehydration from those associated with the expression of summer dormancy. Consequently, this type of endogenous (endo-) dormancy can be tested only in plants that are not subjected to moisture deficit. Summer dormancy can be defined by four criteria, one of which is considered optional: (1) reduction or cessation of leaf production and expansion; (2) senescence of mature foliage; (3) dehydration of surviving organs; and (4, optional) formation of resting organs. The proposed terminology recognizes two levels of summer dormancy: (a) complete dormancy, when cessation of growth is associated with full senescence of foliage and induced dehydration of leaf bases; and (b) incomplete dormancy, when leaf growth is partially inhibited and is associated with moderate levels of foliage senescence. Summer dormancy is expressed under increasing photoperiod and temperature. It is under hormonal control and usually associated with flowering and a reduction in metabolic activity in meristematic tissues. Dehydration tolerance and dormancy are independent phenomena and differ from the adaptations of resurrection plants. • Conclusions Summer dormancy has been correlated with superior survival after severe and repeated summer drought in a large range of perennial grasses. In the face of increasing aridity, this trait could be used in the development of cultivars that are able to meet agronomic and environmental goals. It is therefore important to have a better understanding of the genetic and environmental control of summer dormancy.
Seed dormancy and ABA signaling
The seed is an important organ in higher plants, it is an important organ for plant survival and species dispersion. The transition between seed dormancy and germination represents a critical stage in the plant life cycle and it is an important ecological and commercial trait. A dynamic balance of synthesis and catabolism of two antagonistic hormones, abscisic acid (ABA) and giberellins (GAs), controls the equilibrium between seed dormancy and germination. Embryonic ABA plays a central role in induction and maintenance of seed dormancy and also inhibits the transition from embryonic to germination growth. Therefore, the ABA metabolism must be highly regulated at both temporal and spatial levels during phase of dessication tolerance. On the other hand, the ABA levels do not depend exclusively on the seeds because sometimes it becomes a strong sink and imports it from the roots and rhizosphere through the xylem and/or phloem. These events are discussed in depth here. Likewise, the role of some recently characterized genes belonging to seeds of woody species and related to ABA signaling are also included. Finally, although four possible ABA receptors have been reported, not much is known about how they mediate ABA signaling transduction. However, new publications seem to show that almost all these receptors lack several properties to consider them as such.
del Carmen Rodriguez-Gacio, Maria; Matilla-Vazquez, Miguel A
Transcript Profiling of Paoenia ostii during Artificial Chilling Induced Dormancy Release Identifies Activation of GA Pathway and Carbohydrate Metabolism
Endo-dormant flower buds must pass through a period of chilling to reinitiate growth and subsequent flowering, which is a major obstacle to the forcing culture of tree peony in winter. Customized cDNA microarray (8×15 K element) was used to investigate gene expression profiling in tree peony 'Feng Dan Bai' buds during 24 d chilling treatment at 0–4°C. According to the morphological changes after the whole plants were transferred to green house, endo-dormancy was released after 18 d chilling treatment, and prolonged chilling treatment increased bud break rate. Pearson correlation hierarchical clustering of sample groups was highly consistent with the dormancy transitions revealed by morphological changes. Totally 3,174 significantly differentially-expressed genes (P<0.05) were observed through endo-dormancy release process, of which the number of up-regulated (1,611) and that of down-regulated (1,563) was almost the same. Functional annotation of differentially-expressed genes revealed that cellular process, metabolic process, response to stimulus, regulation of biological process and development process were well-represented. Hierarchical clustering indicated that activation of genes involved in carbohydrate metabolism (Glycolysis, Citrate cycle and Pentose phosphate pathway), energy metabolism and cell growth. Based on the results of GO analysis, totally 51 probes presented in the microarray were associated with GA response and GA signaling pathway, and 22 of them were differently expressed. The expression profiles also revealed that the genes of GA biosynthesis, signaling and response involved in endo-dormancy release. We hypothesized that activation of GA pathway played a central role in the regulation of dormancy release in tree peony.
Liu, Chunying; Zhang, Yang; Zheng, Guosheng
Transcript profiling of Paoenia ostii during artificial chilling induced dormancy release identifies activation of GA pathway and carbohydrate metabolism.
Endo-dormant flower buds must pass through a period of chilling to reinitiate growth and subsequent flowering, which is a major obstacle to the forcing culture of tree peony in winter. Customized cDNA microarray (8×15 K element) was used to investigate gene expression profiling in tree peony 'Feng Dan Bai' buds during 24 d chilling treatment at 0-4°C. According to the morphological changes after the whole plants were transferred to green house, endo-dormancy was released after 18 d chilling treatment, and prolonged chilling treatment increased bud break rate. Pearson correlation hierarchical clustering of sample groups was highly consistent with the dormancy transitions revealed by morphological changes. Totally 3,174 significantly differentially-expressed genes (P<0.05) were observed through endo-dormancy release process, of which the number of up-regulated (1,611) and that of down-regulated (1,563) was almost the same. Functional annotation of differentially-expressed genes revealed that cellular process, metabolic process, response to stimulus, regulation of biological process and development process were well-represented. Hierarchical clustering indicated that activation of genes involved in carbohydrate metabolism (Glycolysis, Citrate cycle and Pentose phosphate pathway), energy metabolism and cell growth. Based on the results of GO analysis, totally 51 probes presented in the microarray were associated with GA response and GA signaling pathway, and 22 of them were differently expressed. The expression profiles also revealed that the genes of GA biosynthesis, signaling and response involved in endo-dormancy release. We hypothesized that activation of GA pathway played a central role in the regulation of dormancy release in tree peony. PMID:23405132
Gai, Shupeng; Zhang, Yuxi; Liu, Chunying; Zhang, Yang; Zheng, Guosheng
Background and Aims Dormancy has been extensively studied in plants which experience severe winter conditions but much less so in perennial herbaceous plants that must survive summer drought. This paper reviews the current knowledge on summer dormancy in both native and cultivated perennial temperate grasses originating from the Mediterranean Basin, and presents a unified terminology to describe this trait. Scope
The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan for implementation in Phase II; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation.
Mushtaq Ahmed; John H. Anderson; Earl R. Berry; Fred Brent; Ming He; Jimmy O. Ong; Mike K. Porter; Randy Roberts; Charles H. Schrader; Lalit S. Shah; Kenneth A. Yackly
Early Entrance Coproduction Plant
The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produce at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objectives of Phase I were to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan for implementation in Phase II; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The work performed under Phase II will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation.
Mushtaq Ahmed; John H. Anderson; Earl R. Berry; Troy Raybold; Lalit S. Shah; Kenneth A. Yackly
The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which uses petroleum coke to produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal and/or other carbonaceous feedstocks. The objectives of Phase I were to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan for implementation in Phase II; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and/or other carbonaceous feedstocks. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation.
Mushtaq Ahmed; John H. Anderson; Charles Benham; Earl R. Berry; Fred Brent; Ming He; Troy Raybold; Lalit S. Shah; Kenneth A. Yackly
The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals. The objective is to have these products produced by technologies capable of using synthesis gas derived from coal or coal in combination with some other carbonaceous feedstock. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site and to develop a Research, Development, and Test Plan (RD and T) for implementation in Phase II. The objective of Phase II is to conduct RD and T as outlined in the Phase I RD and T Plan to enhance the development and commercial acceptance of Coproduction technology that produces high-value products, particularly those that are critical to our domestic fuel and power requirements. The project will resolve critical knowledge and technology gaps on the integration of gasification and downstream processing to coproduce some combination of power, fuels, and chemicals from coal and other feedstocks. The objective of Phase III is to develop an engineering design package and a financing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information that will be needed to move the EECP forward to detailed design, construction, and operation by industry.
Lalit S. Shah; William K. Davis
RNAi in budding yeast
RNAi, a gene-silencing pathway triggered by double-stranded RNA, is conserved in diverse eukaryotic species but has been lost in the model budding yeast, Saccharomyces cerevisiae. Here, we show that RNAi is present in other budding-yeast species, including Saccharomyces castellii and Candida albicans. These species use noncanonical Dicer proteins to generate siRNAs, which mostly correspond to transposable elements and Y' subtelomeric repeats. In S. castellii, RNAi mutants are viable but have excess Y' mRNA levels. In S. cerevisiae, introducing Dicer and Argonaute of S. castellii restores RNAi, and the reconstituted pathway silences endogenous retrotransposons. These results identify a novel class of Dicer proteins, bring the tool of RNAi to the study of budding yeasts, and bring the tools of budding yeast to the study of RNAi.
Mower, Jeffrey P.; Wolfe, Kenneth H.; Fink, Gerald R.; Bartel, David P.
Fruitfulness of grape vine buds
in the axil of each leaf all along the length of its shoots. Grape buds are generally classified as mixed buds, i.e., both leaves and flowers develop from the same bud. Four types of buds are recognized in the grapevine which, for sake of brevity, may be referred to as (a) primary, (b) secondary or accessory or replacement, (c) basal,
S. D. Khanduja; V. R. Balasubrahmanyam
Project BudBurst
NSDL National Science Digital Library
Project BudBurst is an interactive website that has people recording their observations of growing plants. You monitor the plants progress and record it on the website. there is a section for teachers about how to implement BudBurst in the classroom, and it includes classroom activities for grades Kindergarten to 12th grade. This section includes activities on how to observe plants, climate affect on plants, and an activity on ecosystems and biomes.
Latitudinal variation in sensitivity of flower bud formation to high temperature in Japanese Taraxacum officinale.
Control of flowering time plays a key role in the successful range expansion of plants. Taraxacum officinale has expanded throughout Japan during the 110 years after it was introduced into a cool temperate region. The present study tested a hypothesis that there is a genetic difference in the bud formation time in relation to temperature along latitudinal gradient of T. officinale populations. In Experiment 1, plants from three populations at different latitudes (26, 36, and 43°N) were grown at three temperatures. Time to flower bud appearance did not significantly differ among the three populations when plants were grown at 14 °C, whereas it increased with increasing latitude when grown at 19 and 24 °C. Rosette diameter was not different among the populations, indicating that the variation in bud formation time reflected a difference in genetic control rather than size variation. The latitudinal variation in bud appearance time was confirmed by Experiment 2 in which plants from 17 population were used. In Experiment 3, the size of plants that exhibited late-flowering was studied to test a hypothesis that the variation in flowering time reflects dormancy of vegetative growth, but the late-flowering plants were found to continue growth, indicating that vegetative dormancy was not the cause of the variation. The results clearly indicate that the degree of suppression of flower bud formation at high temperature decreases with latitude from north to south, which is under genetic control. PMID:24585133
Yoshie, Fumio
47 CFR 69.110 - Entrance facilities.
Code of Federal Regulations, 2013 CFR
...setting entrance facilities charges. (e) Except as provided...discounts in entrance facilities charges within each study area used for the purpose of jurisdictional separations, in which interconnectors...discounts in entrance facilities charges within the study area...
Entrance Into Juvenile Male Prostitution.
National Technical Information Service (NTIS)
Forty-six juvenile male prostitutes and 50 juvenile male non-prostitute delinquents were studied to provide information on: the process of entrance into prostitution; early sexual experience; exposure to prostitution; and associated criminal and drug invo...
J. James
Control of seed dormancy in Nicotiana plumbaginifolia : post-imbibition abscisic acid synthesis imposes dormancy maintenance
. The physiological characteristics of seed dormancy in Nicotiana plumbaginifolia Viv. are described. The level of seed dormancy is defined by the delay in seed germination (i.e the time required prior to\\u000a germination) under favourable environmental conditions. A wild-type line shows a clear primary dormancy, which is suppressed\\u000a by afterripening, whereas an abscisic acid (ABA)-deficient mutant shows a non-dormant phenotype.
Philippe Grappin; Denise Bouinot; Bruno Sotta; Emile Miginiac; Marc Jullien
Tumour dormancy in breast cancer: an update
Delayed recurrences, common in breast cancer, are well explained by the concept of tumour dormancy. Numerous publications describe clinical times to disease recurrence or death, using mathematical approaches to infer mechanisms responsible for delayed recurrences. However, most of the clinical literature discussing tumour dormancy uses data from over a half century ago and much has since changed. This review explores how current breast cancer treatment could change our understanding of the biology of breast cancer tumour dormancy, and summarizes relevant experimental models to date. Current knowledge gaps are highlighted and potential areas of future research are identified.
Brackstone, Muriel; Townson, Jason L; Chambers, Ann F
The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using petroleum coke and ChevronTexaco's proprietary gasification technology. The objective of Phase I was to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are Texaco Energy Systems LLC. (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). ChevronTexaco is providing gasification technology and Fischer-Tropsch technology developed by Rentech, GE is providing combustion turbine technology, Praxair is providing air separation technology and KBR is providing engineering. Each of the EECP subsystems were assessed for technical risks and barriers. A plan was identified to mitigate the identified risks (Phase II RD&T Plan, October 2000). The RD&T Plan identified F-T reactor scale-up as a potential technical risk. The objective of Task 2.3 was to confirm engineering models that allow scale-up to commercial slurry phase bubble column (SPBC) reactors operating in the churn-turbulent flow regime. In developmental work outside the scope of this project, historical data, literature references, and a scale-up from a 1 1/2-in. (3.8 cm) to 6-ft (1.8 m) SPBC reactor have been reviewed. This review formed the background for developing scale-up models for a SPBC reactor operating in the churn-turbulent flow regime. The necessary fundamental physical parameters have been measured and incorporated into the mathematical catalyst/kinetic model developed from the SPBC and CSTR work outside the scope of this EECP project. The mathematical catalyst/kinetic model was used to compare to experimental data obtained at Rentech during the EECP Fischer-Tropsch Confirmation Run (Task 2.1; reported separately). The prediction of carbon monoxide (CO) conversion as a function of days on stream compares quite closely to the experimental data.
Randy Roberts
The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are TES (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. During Phase I the team identified the integration of the water produced in the F-T synthesis section with the gasification section as an area of potential synergy. By utilizing the F-T water in the petroleum coke slurry for the gasifier, the EECP can eliminate a potential waste stream and reduce capital costs. There is a low technical risk for this synergy, however, the economic risk, particularly in regards to the water, can be high. The economic costs include the costs of treating the water to meet the locally applicable environmental standards. This option may require expensive chemicals and treatment facilities. EECP Phase II included tests conducted to confirm the viability of integrating F-T water in the slurry feed for the gasifier. Testing conducted at ChevronTexaco's Montebello Technology Center (MTC) included preparing slurries made using petroleum coke with F-T water collected at the LaPorte Alternative Fuels Development Unit (AFDU). The work included bench scale tests to determine the slurry ability of the petroleum coke and F-T water. The results of the tests show that F-T water does not adversely affect slurries for the gasifier. There are a few cases where in fact the addition of F-T water caused favorable changes in viscosity of the slurries. This RD&T task was executed in Phase II and results are reported herein.
Abdalla H. Ali; Raj Kamarthi; John H. Anderson; Earl R. Berry; Charles H. Schrader; Lalit S. Shah
Phytochrome B Represses Teosinte Branched1 Expression and Induces Sorghum Axillary Bud Outgrowth in Response to Light Signals1
Light is one of the environmental signals that regulate the development of shoot architecture. Molecular mechanisms regulating shoot branching by light signals have not been investigated in detail. Analyses of light signaling mutants defective in branching provide insight into the molecular events associated with the phenomenon. It is well documented that phytochrome B (phyB) mutant plants display constitutive shade avoidance responses, including increased plant height and enhanced apical dominance. We investigated the phyB-1 mutant sorghum (Sorghum bicolor) and analyzed the expression of the sorghum Teosinte Branched1 gene (SbTB1), which encodes a putative transcription factor that suppresses bud outgrowth, and the sorghum dormancy-associated gene (SbDRM1), a marker of bud dormancy. Buds are formed in the leaf axils of phyB-1; however, they enter into dormancy soon after their formation. The dormant state of phyB-1 buds is confirmed by the high level of expression of the SbDRM1 gene. The level of SbTB1 mRNA is higher in the buds of phyB-1 compared to wild type, suggesting that phyB mediates the growth of axillary shoots in response to light signals in part by regulating the mRNA abundance of SbTB1. These results are confirmed by growing wild-type seedlings with supplemental far-red light that induces shade avoidance responses. We hypothesize that active phyB (Pfr) suppresses the expression of the SbTB1 gene, thereby inducing bud outgrowth, whereas environmental conditions that inactivate phyB allow increased expression of SbTB1, thereby suppressing bud outgrowth.
Kebrom, Tesfamichael H.; Burson, Byron L.; Finlayson, Scott A.
Hormone Cross-Talk in Seed Dormancy
The choice to become dormant versus continuing to grow is observed in a variety of organisms in response to specific developmental\\u000a and environmental signals. In higher plants this is most obvious during both the establishment and breaking of seed dormancy.\\u000a With the advent of molecular genetic analysis, particularly in Arabidopsis, genes involved in the establishment and breaking of seed dormancy
Siobhan M. Brady; Peter McCourt
The overall objective of this project is the three phase development of an Early Entrance Coproduction Plant (EECP) which produces at least one product from at least two of the following three categories: (1) electric power (or heat), (2) fuels, and (3) chemicals using ChevronTexaco's proprietary gasification technology. The objective of Phase I is to determine the feasibility and define the concept for the EECP located at a specific site; develop a Research, Development, and Testing (RD&T) Plan to mitigate technical risks and barriers; and prepare a Preliminary Project Financing Plan. The objective of Phase II is to implement the work as outlined in the Phase I RD&T Plan to enhance the development and commercial acceptance of coproduction technology. The objective of Phase III is to develop an engineering design package and a financing and testing plan for an EECP located at a specific site. The project's intended result is to provide the necessary technical, economic, and environmental information needed by industry to move the EECP forward to detailed design, construction, and operation. The partners in this project are TES (a subsidiary of ChevronTexaco), General Electric (GE), Praxair, and Kellogg Brown & Root (KBR) in addition to the U.S. Department of Energy (DOE). TES is providing gasification technology and Fischer-Tropsch (F-T) technology developed by Rentech, GE is providing combustion turbine technology, Praxair is providing air separation technology, and KBR is providing engineering. Each of the EECP subsystems were assessed for technical risks and barriers. A plan was identified to mitigate the identified risks (Phase II RD&T Plan, October 2000). The RD&T Plan identified petroleum coke characteristics as a potential technical risk. The composition of petroleum coke varies from one refinery to another. Petroleum coke characteristics are a function of the crude oil slate available at the refinery and the coker operating parameters. The specific petroleum coke characteristics at a refinery affect the design of the Gasification and Acid Gas Removal (AGR) subsystems. Knowing the petroleum coke composition provides the necessary data to proceed to the EECP Phase III engineering design of the gasification process. Based on ChevronTexaco's experience, the EECP team ranked the technical, economic, and overall risks of the petroleum coke composition related to the gasification subsystem as low. In Phase I of the EECP Project, the Motiva Port Arthur Refinery had been identified as the potential EECP site. As a result of the merger between Texaco and Chevron in October 2001, Texaco was required to sell its interest in the Motiva Enterprises LLC joint venture to Shell Oil Company and Saudi Refining Inc. To assess the possible impact of moving the proposed EECP host site to a ChevronTexaco refinery, samples of petroleum coke from two ChevronTexaco refineries were sent to MTC for bench-scale testing. The results of the analysis of these samples were compared to the Phase I EECP Gasification Design Basis developed for Motiva's Port Arthur Refinery. The analysis confirms that if the proposed EECP is moved to a new refinery site, the Phase I EECP Gasification Design Basis would have to be updated. The lower sulfur content of the two samples from the ChevronTexaco refineries indicates that if one of these sites were selected, the Sulfur Recovery Unit (SRU) might be sized smaller than the current EECP design. This would reduce the capital expense of the SRU. Additionally, both ChevronTexaco samples have a higher hydrogen to carbon monoxide ratio than the Motiva Port Arthur petroleum coke. The higher hydrogen to carbon monoxide ratio could give a slightly higher F-T products yield from the F-T Synthesis Reactor. However, the EECP Gasification Design Basis can not be updated until the site for the proposed EECP site is finalized. Until the site is finalized, the feedstock (petroleum coke) characteristics are a low risk to the EECP project.
Abdalla H. Ali; John H. Anderson; Earl R. Berry; Charles H. Schrader; Lalit S. Shah
"Bud, Not Buddy."
ERIC Educational Resources Information Center
Discusses the award-winning book "Bud, Not Buddy" written by Christopher Paul Curtis. Lists different versions of the book; suggests learning activities; lists sources for biographical information and interviews with Curtis, teacher guides, professional articles, and other Depression era novels; and provides a citation for the author's Newberry…
Brodie, Carolyn S.
Models, mechanisms and clinical evidence for cancer dormancy.
Patients with cancer can develop recurrent metastatic disease with latency periods that range from years even to decades. This pause can be explained by cancer dormancy, a stage in cancer progression in which residual disease is present but remains asymptomatic. Cancer dormancy is poorly understood, resulting in major shortcomings in our understanding of the full complexity of the disease. Here, I review experimental and clinical evidence that supports the existence of various mechanisms of cancer dormancy including angiogenic dormancy, cellular dormancy (G0-G1 arrest) and immunosurveillance. The advances in this field provide an emerging picture of how cancer dormancy can ensue and how it could be therapeutically targeted. PMID:17957189
Aguirre-Ghiso, Julio A
Background Dormancy associated MADS-box (DAM) genes are candidates for the regulation of growth cessation and terminal bud formation in peach. These genes are not expressed in the peach mutant evergrowing, which fails to cease growth and enter dormancy under dormancy-inducing conditions. We analyzed the phylogenetic relationships among and the rates and patterns of molecular evolution within DAM genes in the phylogenetic context of the MADS-box gene family. Results The peach DAM genes grouped with the SVP/StMADS11 lineage of type II MIKCC MADS-box genes. Phylogenetic analyses suggest that the peach SVP/StMADS11-like gene family, which contains significantly more members than annual model plants, expanded through serial tandem gene duplication. We found evidence of strong purifying selection acting to constrain functional divergence among the peach DAM genes and only a single codon, located in the C-terminal region, under significant positive selection. Conclusion Because all DAM genes are expressed in peach and are subjected to strong purifying selection we suggest that the duplicated genes have been maintained by subfunctionalization and/or neofunctionalization. In addition, this pattern of selection suggests that the DAM genes are important for peach growth and development.
Jimenez, Sergio; Lawton-Rauh, Amy L; Reighard, Gregory L; Abbott, Albert G; Bielenberg, Douglas G
Entrance Assessment and Student Success.
Reviews the history of standardized assessment programs for college entrance, with particular emphasis on the community college testing programs. Examines responses of California community colleges to a 1982-83 survey of assessment procedures. Offers recommendations regarding the essential components of effective assessment. (DMM)
Rounds, Jeanine Crandall; Anderson, Don
Dehydrins expression related to timing of bud burst in Norway spruce.
Cold deacclimation and preparation to flushing likely requires rehydration of meristems. Therefore, water stress related genes, such as dehydrins (DHN), might play an important role in providing protection during winter dormancy, deacclimation and bud burst timing processes. Here we report the sequence analysis of several Norway spruce DHN identified in late and early flushing suppressive subtraction hybridization cDNA libraries and in our Norway spruce EST database. We obtained 15 cDNAs, representing eight genes from three distinct types of DHN, and studied differential expression of these genes before and during bud burst in spring, using qRT-PCR. We found the visible reduction in transcript level of most DHN towards the bud burst, supported by a significant down-regulation of the DHN in needles during experimental induction of bud burst applied at three time points during autumn in Norway spruce grafts. For most of the DHN transcripts, their expression levels in late-flushing spruces were significantly higher than in the early flushing ones at the same calendar dates but were remarkably similar at the same bud developmental stage. From our results we may conclude that the difference between the early and the late families is in timing of the molecular processes leading to bud burst due to differences in their response to the increasing temperature in the spring. They are induced much earlier in the early flushing families. PMID:18493789
Yakovlev, Igor A; Asante, Daniel K A; Fossdal, Carl Gunnar; Partanen, Jouni; Junttila, Olavi; Johnsen, Oystein
Summer Dormancy and Endophyte Infection in Tall Fescue
Summer dormancy is a drought escape mechanism for some Mediterranean-origin perennial grasses. Little is known of the influence of fungal endophytes (Neotyphodium spp.) on the expression of summer dormancy in their grass hosts or of the possible role of endophytes in host drought survival. Research was conducted to investigate interactions between summer dormancy potential and endophyte symbiosis as related to
J. L. Underwood; C. P. West; D. P. Malinowski; C. A. Guerber; B. C. Grigg
Identification of cis-Elements That Regulate Gene Expression during Initiation of Axillary Bud Outgrowth in Arabidopsis
Growth regulation associated with dormancy is an essential element in plant life cycles. To reveal regulatory mechanisms of bud outgrowth, we analyzed transcriptomes of axillary shoots before and after main stem decapitation in Arabidopsis (Arabidopsis thaliana). We searched for any enriched motifs among the upstream regions of up-regulated and down-regulated genes after decapitation. The promoters of down-regulated genes were enriched
Kiyoshi Tatematsu; Sally Ward; Ottoline Leyser; Yuji Kamiya; Eiji Nambara
On dormancy strategies in tardigrades.
In this review we analyze the dormancy strategies of metazoans inhabiting "hostile to life" habitats, which have a strong impact on their ecology and in particular on the traits of their life history. Tardigrades are here considered a model animal, being aquatic organisms colonizing terrestrial habitats. Tardigrades evolved a large variety of dormant stages that can be ascribed to diapause (encystment, cyclomorphosis, resting eggs) and cryptobiosis (anhydrobiosis, cryobiosis, anoxibiosis). In tardigrades, diapause and cryptobiosis can occur separately or simultaneously, consequently the adoption of one adaptive strategy is not necessarily an alternative to the adoption of the other. Encystment and cyclomorphosis are characterized by seasonal cyclic changes in morphology and physiology of the animals. They share several common features and their evolution is strictly linked to the molting process. A bet-hedging strategy with different patterns of egg hatching time has been observed in a tardigrade species. Four categories of eggs have been identified: subitaneous, delayed-hatching, abortive and diapause resting eggs, which needs a stimulus to hatch (rehydration after a period of desiccation). Cryptobiotic tardigrades are able to withstand desiccation (anhydrobiosis) and freezing (cryobiosis) at any stage of their life-cycle. This ability involves a complex array of factors working at molecular (bioprotectans), physiological and structural levels. Animal survival and the accumulation of molecular damage are related to the time spent in the cryptobiotic state, to the abiotic parameters during the cryptobiotic state, and to the conditions during initial and final phases of the process. Cryptobiosis evolved independently at least two times in tardigrades, in eutardigrades and in echiniscoids. Within each evolutionary line, the absence of cryptobiotic abilities is more related to selective pressures to local habitat adaptation than to phylogenetic relationships. The selective advantages of cryptobiosis (e.g. persistency in "hostile to life" habitats, reduction of competitors, parasites and predators, escaping in time from stressful conditions) could explain the high tardigrade species diversity and number of specimens found in habitats that dry out compared to freshwater habitats. PMID:21402076
Guidetti, Roberto; Altiero, Tiziana; Rebecchi, Lorena
30 CFR 18.37 - Lead entrances.
Code of Federal Regulations, 2010 CFR
...2009-07-01 false Lead entrances. 18.37 Section 18...Requirements § 18.37 Lead entrances. (a) Insulated cable...through a stuffing-box lead entrance. All sharp edges that might...removed from stuffing boxes and packing nuts. (b) Stuffing...
...2010-07-01 false Lead entrances. 18.37 Section 18...Requirements § 18.37 Lead entrances. (a) Insulated cable...through a stuffing-box lead entrance. All sharp edges that might...removed from stuffing boxes and packing nuts. (b) Stuffing...
Cold acclimation and floral development in almond bud break: insights into the regulatory pathways.
In temperate fruit trees, seasonal dormancy and cold acclimation have a major impact on blooming time and, consequently, fruit production. To gain insight into the still unclear molecular processes underlying blooming, expression of genes putatively involved in the cold response was studied in almond (Prunus dulcis Mill.), which is the earliest fruit tree in the family Rosaceae to bloom. The transcript levels of two C-repeat binding factor (PdCBF) genes and one of their putative targets, PdDehydrin1 (PdDHN1), were analysed in flower buds and shoot internodes during seasonal dormancy up to bud break. In parallel, expression of candidate genes related to flower development was also followed. In a 2-year study, PdCBF2 showed a progressive increase in transcript abundance during the autumn in close correlation with cold acclimation, while high transcript levels of PdCBF1 and PdDHN1 were already found by summer. After bud break, with temperatures still within the chilling range, both PdCBF genes and PdDHN1 were found to sharply reduce transcription in flower buds and internodes, suggesting damping of CBF-mediated cold signalling during growth resumption, in correlation with cold hardiness decline. Flower bud break was also followed by a decrease in the expression of PdGA20OX, a candidate gene involved in gibberellin biosynthesis, and an increase in the expression of two homeotic genes related to floral organ development, PdMADS1 and -3. These genes may also be relevant players in the regulation of anthesis in this model Rosaceae species. PMID:22685307
Barros, Pedro M; Gonçalves, Nuno; Saibo, Nelson J M; Oliveira, M Margarida
Differential dormancy of co-occurring copepods
NASA Astrophysics Data System (ADS)
Four species of planktonic calanoid copepods that co-occur in the California Current System ( Eucalanus californicus Johnson, Rhincalanus nasutus Giesbrecht, Calanus pacificus californicus Brodsky, and Metridia pacifica Brodsky) were investigated for evidence of seasonal dormancy in the San Diego Trough. Indices used to differentiate actively growing from dormant animals included developmental stage structure and vertical distribution; activity of aerobic metabolic enzymes (Citrate Synthase and the Electron Transfer System complex); investment in depot lipids (wax esters and triacylglycerols); in situ grazing activity from gut fluorescence; and egg production rates in simulated in situ conditions. None of the 4 species exhibited a canonical calanoid pattern of winter dormancy - i.e., synchronous developmental arrest as copepodid stage V, descent into deep waters, reduced metabolism, and lack of winter reproduction. Instead, Calanus pacificus californicus has a biphasic life history in this region, with an actively reproducing segment of the population in surface waters overlying a deep dormant segment in winter. Eucalanus californicus is dormant as both adult females and copepodid V's, although winter females respond relatively rapidly to elevated food and temperature conditions; they begin feeding and producing eggs within 2-3 days. Rhincalanus nasutus appears to enter dormancy as adult females, although the evidence is equivocal. Metridia pacifica shows no evidence of dormancy, with sustained active feeding, diel vertical migration behavior, and elevated activity of metabolic enzymes in December as well as in June. The four species also differ markedly in water content, classes of storage lipids, and specific activity of Citrate Synthase. These results suggest that copepod dormancy traits and structural composition reflect diverse adaptations to regional environmental conditions rather than a uniform, canonical series of traits that remain invariant among taxa and fixed across a species' range. Such interspecific and regional differences in life history traits need to be incorporated in models simulating Eastern Boundary Current pelagic ecosystem dynamics.
Ohman, Mark D.; Drits, Aleksandr V.; Elizabeth Clarke, M.; Plourde, Stéphane
PtABI3 Impinges on the Growth and Differentiation of Embryonic Leaves during Bud Set in Poplar
The Arabidopsis ABSCISIC ACID–INSENSITIVE3 (ABI3) protein plays a crucial role during late seed development and has an additional function at the vegetative meristem, particularly during periods of growth-arresting conditions and quiescence. Here, we show that the ABI3 homolog of poplar (PtABI3) is expressed in buds during natural bud set. Expression occurs clearly after perception of the critical daylength that initiates bud set and dormancy in poplar. In short-day conditions mimicking natural bud set, the expression of a chimeric PtABI3::?-glucuronidase (GUS) gene occurred in those organs and cells of the apex that grow actively but will undergo arrest: the young embryonic leaves, the subapical meristem, and the procambial strands. If PtABI3 is overexpressed or downregulated, bud development in short-day conditions is altered. Constitutive overexpression of PtABI3 resulted in apical buds with large embryonic leaves and small stipules, whereas in antisense lines, bud scales were large and leaves were small. Thus, PtABI3 influences the size and ratio of embryonic leaves and bud scales/stipules that differentiate from the primordia under short-day conditions. These observations, together with the expression of PtABI3::GUS in embryonic leaves but not in bud scales/stipules, support the idea that wild-type PtABI3 is required for the relative growth rate and differentiation of embryonic leaves inside the bud. These experiments reveal that ABI3 plays a role in the cellular differentiation of vegetative tissues, in addition to its function in seeds.
Rohde, Antje; Prinsen, Els; De Rycke, Riet; Engler, Gilbert; Van Montagu, Marc; Boerjan, Wout
Expression analysis of phytochromes A, B and floral integrator genes during the entry and exit of grapevine-buds from endodormancy.
A common molecular regulatory pathway that involves PHYA, PHYB and floral integrator genes CONSTANS (CO), FLOWERING LOCUS T (FT) and SUPRESSOR OF OVEREXPRESSION OF CO1 (SOC1) has been suggested to participate in the regulation of photoperiod dependent processes such as flowering and dormancy. In grapevines (Vitis vinifera L.), decreasing photoperiod and low temperatures trigger the transition of buds into endodormancy (ED), a process that is accompanied by drastic changes in gene expression of VvPHYA and B in leaves. To analyse the relationship of VvPHYA, VvPHYB, and grape homologues of Arabidopsis floral integrator genes VvCO, VvFT, VvMADS8, with ED, a comparative expression analysis of these genes was performed in grapevine-leaves and buds before, during and after the transition of buds into ED. The expression of all the above genes in the bud-tissue, and the fact that photoperiod regulates differently the expression of VvPHYA and B in buds than in leaves, suggests that the bud might be an autonomous or semi-autonomous organ in perceiving and transducing the photoperiod signal. On the other hand, the coordinated down-regulation of VvFT in leaves and buds during the transition of buds into ED, and its subsequent up-regulation following the application of dormancy-breaking compounds, hydrogen cyanamide (HC) and sodium azide, suggests that VvFT could play a key role in stimulating bud-growth by repressing their entry into ED. PMID:21453983
Pérez, Francisco J; Kühn, N; Vergara, R
Influenza virus assembly and budding.
Influenza A virus causes seasonal epidemics, sporadic pandemics and is a significant global health burden. Influenza virus is an enveloped virus that contains a segmented negative strand RNA genome. Assembly and budding of progeny influenza virions is a complex, multi-step process that occurs in lipid raft domains on the apical membrane of infected cells. The viral proteins hemagglutinin (HA) and neuraminidase (NA) are targeted to lipid rafts, causing the coalescence and enlargement of the raft domains. This clustering of HA and NA may cause a deformation of the membrane and the initiation of the virus budding event. M1 is then thought to bind to the cytoplasmic tails of HA and NA where it can then polymerize and form the interior structure of the emerging virion. M1, bound to the cytoplasmic tails of HA and NA, additionally serves as a docking site for the recruitment of the viral RNPs and may mediate the recruitment of M2 to the site of virus budding. M2 initially stabilizes the site of budding, possibly enabling the polymerization of the matrix protein and the formation of filamentous virions. Subsequently, M2 is able to alter membrane curvature at the neck of the budding virus, causing membrane scission and the release of the progeny virion. This review investigates the latest research on influenza virus budding in an attempt to provide a step-by-step analysis of the assembly and budding processes for influenza viruses. PMID:21237476
Rossman, Jeremy S; Lamb, Robert A
ESCRT requirements for EIAV budding
Background Retroviruses and many other enveloped viruses usurp the cellular ESCRT pathway to bud from cells. However, the stepwise process of ESCRT-mediated virus budding can be challenging to analyze in retroviruses like HIV-1 that recruit multiple different ESCRT factors to initiate budding. Results In this study, we characterized the ESCRT factor requirements for budding of Equine Infectious Anemia Virus (EIAV), whose only known direct ESCRT protein interaction is with ALIX. siRNA depletion of endogenous ESCRT proteins and "rescue" experiments with exogenous siRNA-resistant wild type and mutant constructs revealed budding requirements for the following ESCRT proteins: ALIX, CHMP4B, CHMP2A and VPS4A or VPS4B. EIAV budding was inhibited by point mutations that abrogate the direct interactions between ALIX:CHMP4B, CHMP4B:CHMP2A, and CHMP2A:VPS4A/B, indicating that each of these interactions is required for EIAV budding. Unexpectedly, CHMP4B depletion led to formation of multi-lobed and long tubular EIAV virions. Conclusions We conclude that EIAV budding requires an ESCRT protein network that comprises EIAV Gag-ALIX-CHMP4B-CHMP2A-VPS4 interactions. Our experiments also suggest that CHMP4B recruitment/polymerization helps control Gag polymerization and/or processing to ensure that ESCRT factor assembly and membrane fission occur at the proper stage of virion assembly. These studies help establish EIAV as a streamlined model system for dissecting the stepwise processes of lentivirus assembly and ESCRT-mediated budding.
Proteomic approach to analyze dormancy breaking of tree seeds
In forest broadleaves from the temperate zone, a large number of species exhibit seed dormancy phenomena. Tree seeds show\\u000a some of the most pronounced and complicated forms of dormancy in the plant kingdom. Many seeds are deeply physiologically\\u000a dormant whatever their moisture level and age. However, dormancy can usually be overcome by a cold or warm stratification\\u000a for several months.
Tomasz Andrzej Paw?owski
Exit from dormancy in microbial organisms.
Bacteria can exist in metabolically inactive states that allow them to survive conditions that are not conducive for growth. Such dormant cells may sense when conditions have improved and re-initiate growth, lest they be outcompeted by their neighbours. Growing bacteria turn over and release large quantities of their cell walls into the environment. Drawing from recent work on the germination of Bacillus subtilis spores, we propose that many microorganisms exit dormancy in response to cell wall muropeptides. PMID:20972452
Dworkin, Jonathan; Shah, Ishita M
7. WALKWAY/ENTRANCE TO ADMINSITRATIVE SITE ADJACENT TO ENTRANCE ROAD AND INTERNAL POLICE POST, LOOKING SOUTHEAST - Manzanar War Relocation Center, Owens Valley off U.S. Highway 395, 6 miles South of Independence, Independence, Inyo County, CA
Effect of Growth Regulators on CO2 Assimilation in Leaves, and its Correlation with the Bud Break Response in Photosynthesis 1
Experiments have been done to confirm the previously reported effect of indoleacetic acid (IAA) on the rate of CO2 assimilation in bean leaves. It was shown that spraying the leaves of a variety of plants caused an increase in the rate of CO2 assimilation from 30% to 100% during the half-hour to 1 hour period following spraying. The only plant tested which did not show such an effect was corn. The breaking of dormancy of axial buds in the bean plant was correlated with an increase in the rate of CO2 assimilation in adjacent leaves for a brief period of time. It has been shown that IAA solution sprayed on 1 leaflet of a leaf can cause an increase in the rate of CO2 assimilation in the other leaflets, and that IAA applied to the cut stem of a leaflet or a developing bud can be transported to adjacent leaves and cause an increase in the CO2 assimilation rate. The reaction caused by IAA is very similar to that caused by the breaking of dormancy of a bud. This indicates that the bud break response in CO2 assimilation in leaves is caused by auxin synthesized in a bud as it begins to grow, and exported into adjacent leaves.
Bidwell, R. G. S.; Turner, Wendy B.
Candidate cave entrances on Mars
USGS Publications Warehouse
This paper presents newly discovered candidate cave entrances into Martian near-surface lava tubes, volcano-tectonic fracture systems, and pit craters and describes their characteristics and exploration possibilities. These candidates are all collapse features that occur either intermittently along laterally continuous trench-like depressions or in the floors of sheer-walled atypical pit craters. As viewed from orbit, locations of most candidates are visibly consistent with known terrestrial features such as tube-fed lava flows, volcano-tectonic fractures, and pit craters, each of which forms by mechanisms that can produce caves. Although we cannot determine subsurface extents of the Martian features discussed here, some may continue unimpeded for many kilometers if terrestrial examples are indeed analogous. The features presented here were identified in images acquired by the Mars Odyssey's Thermal Emission Imaging System visible-wavelength camera, and by the Mars Reconnaissance Orbiter's Context Camera. Select candidates have since been targeted by the High-Resolution Imaging Science Experiment. Martian caves are promising potential sites for future human habitation and astrobiology investigations; understanding their characteristics is critical for long-term mission planning and for developing the necessary exploration technologies.
Cushing, Glen E.
Seed dormancy and germination--emerging mechanisms and new hypotheses
Seed dormancy has played a significant role in adaptation and evolution of seed plants. While its biological significance is clear, molecular mechanisms underlying seed dormancy induction, maintenance and alleviation still remain elusive. Intensive efforts have been made to investigate gibberellin and abscisic acid metabolism in seeds, which greatly contributed to the current understanding of seed dormancy mechanisms. Other mechanisms, which might be independent of hormones, or specific to the seed dormancy pathway, are also emerging from genetic analysis of "seed dormancy mutants." These studies suggest that chromatin remodeling through histone ubiquitination, methylation and acetylation, which could lead to transcription elongation or gene silencing, may play a significant role in seed dormancy regulation. Small interfering RNA and/or long non-coding RNA might be a trigger of epigenetic changes at the seed dormancy or germination loci, such as DELAY OF GERMINATION1. While new mechanisms are emerging from genetic studies of seed dormancy, novel hypotheses are also generated from seed germination studies with high throughput gene expression analysis. Recent studies on tissue-specific gene expression in tomato and Arabidopsis seeds, which suggested possible "mechanosensing" in the regulatory mechanisms, advanced our understanding of embryo-endosperm interaction and have potential to re-draw the traditional hypotheses or integrate them into a comprehensive scheme. The progress in basic seed science will enable knowledge translation, another frontier of research to be expanded for food and fuel production.
Nonogaki, Hiroyuki
Models, mechanisms and clinical evidence for cancer dormancy
Patients with cancer can develop recurrent metastatic disease with latency periods that range from years even to decades. This pause can be explained by cancer dormancy, a stage in cancer progression in which residual disease is present but remains asymptomatic. Cancer dormancy is poorly understood, resulting in major shortcomings in our understanding of the full complexity of the disease. Here,
Julio A. Aguirre-Ghiso
Plant hormone interactions during seed dormancy release and germination
This review focuses mainly on eudicot seeds, and on the interactions between abscisic acid (ABA), gibber- ellins (GA), ethylene, brassinosteroids (BR), auxin and cytokinins in regulating the interconnected molecular processes that control dormancy release and germi- nation. Signal transduction pathways, mediated by environmental and hormonal signals, regulate gene expression in seeds. Seed dormancy release and germination of species with coat
Birgit Kucera; Marc Alan Cohn; Gerhard Leubner-Metzger
Environmental control of dormancy in weed seed banks in soil
Dormancy is a common attribute of many weed seed populations and this usually hampers the task of predicting timing and extent of emergence of weeds. Both the number of established plants and the timing of emergence of a weed are strongly related to the dynamics of dormancy release of the seed population. In this paper, we discuss the different factors
Roberto L. Benech-arnold; Rodolfo A Sánchez; Frank Forcella; Betina C. Kruk; Claudio M. Ghersa
Apical dominance in saffron and the involvement of the branching enzymes CCD7 and CCD8 in the control of bud sprouting
Background In saffron (Crocus sativus), new corms develop at the base of every shoot developed from the maternal corm, a globular underground storage stem. Since the degree of bud sprouts influences the number and size of new corms, and strigolactones (SLs) suppress growth of pre-formed axillary bud, it was considered appropriate to investigate SL involvement in physiology and molecular biology in saffron. We focused on two of the genes within the SL pathway, CCD7 and CCD8, encoding carotenoid cleavage enzymes required for the production of SLs. Results The CsCCD7 and CsCCD8 genes are the first ones isolated and characterized from a non-grass monocotyledonous plant. CsCCD7 and CsCCD8 expression showed some overlapping, although they were not identical. CsCCD8 was highly expressed in quiescent axillary buds and decapitation dramatically reduced its expression levels, suggesting its involvement in the suppression of axillary bud outgrowth. Furthermore, in vitro experiments showed also the involvement of auxin, cytokinin and jasmonic acid on the sprouting of axillary buds from corms in which the apical bud was removed. In addition, CsCCD8 expression, but not CsCCD7, was higher in the newly developed vascular tissue of axillary buds compared to the vascular tissue of the apical bud. Conclusions We showed that production and transport of auxin in saffron corms could act synergistically with SLs to arrest the outgrowth of the axillary buds, similar to the control of above-ground shoot branching. In addition, jasmonic acid seems to play a prominent role in bud dormancy in saffron. While cytokinins from roots promote bud outgrowth. In addition the expression results of CsCCD8 suggest that SLs could positively regulate procambial activity and the development of new vascular tissues connecting leaves with the mother corm.
Dynamic thermal time model of cold hardiness for dormant grapevine buds
Background and Aims Grapevine (Vitis spp.) cold hardiness varies dynamically throughout the dormant season, primarily in response to changes in temperature. The development and possible uses of a discrete-dynamic model of bud cold hardiness for three Vitis genotypes are described. Methods Iterative methods were used to optimize and evaluate model parameters by minimizing the root mean square error between observed and predicted bud hardiness, using up to 22 years of low-temperature exotherm data. Three grape cultivars were studied: Cabernet Sauvignon, Chardonnay (both V. vinifera) and Concord (V. labruscana). The model uses time steps of 1 d along with the measured daily mean air temperature to calculate the change in bud hardiness, which is then added to the hardiness from the previous day. Cultivar-dependent thermal time thresholds determine whether buds acclimate (gain hardiness) or deacclimate (lose hardiness). Key Results The parameterized model predicted bud hardiness for Cabernet Sauvignon and Chardonnay with an r2 = 0·89 and for Concord with an r2 = 0·82. Thermal time thresholds and (de-)acclimation rates changed between the early and late dormant season and were cultivar dependent but independent of each other. The timing of these changes was also unique for each cultivar. Concord achieved the greatest mid-winter hardiness but had the highest deacclimation rate, which resulted in rapid loss of hardiness in spring. Cabernet Sauvignon was least hardy, yet maintained its hardiness latest as a result of late transition to eco-dormancy, a high threshold temperature required to induce deacclimation and a low deacclimation rate. Conclusions A robust model of grapevine bud cold hardiness was developed that will aid in the anticipation of and response to potential injury from fluctuations in winter temperature and from extreme cold events. The model parameters that produce the best fit also permit insight into dynamic differences in hardiness among genotypes.
Ferguson, John C.; Tarara, Julie M.; Mills, Lynn J.; Grove, Gary G.; Keller, Markus
Thermal and hormonal regulation of the dormancy-germination transition in Amaranthus tuberculatus seeds
Summary The transition from seed dormancy to germination is a multi-step process. However, distinguishing between physiological processes involved in seed dormancy alleviation and those involved in germination has been difficult. We studied the seed dormancy alleviation process in Amaranthus tuberculatus, an important weed species in midwestern USA. Using three A. tuberculatus biotypes that differ in dormancy level, it was determined
Classification and ecological relationships of seed dormancy in a seasonal moist tropical forest, Panama, Central America
This is the first study to determine the class of seed dormancy (or non-dormancy) of a large number of native tree species in a tropical forest, the seasonal moist tropical forest of the Panama Canal Watershed (PCW), or to test the relationships between class of dormancy (or non-dormancy) and various seed and ecological characteristics of the constituent species. Fresh seeds
Adriana Sautu; Jerry M. Baskin; Carol C. Baskin; Jose Deago; Richard Condit
William Shatner and the Grand Entrance
NASA Video Gallery
As NASA prepares for Curiosity rover landing on Mars, William Shatner shares this thrilling story of NASA's hardest planetary science mission to date. The video titled, "Grand Entrance," guides vie...
Cancer stem cells, tumor dormancy, and metastasis
Tumor cells can persist undetectably for an extended period of time in primary tumors and in disseminated cancer cells. Very little is known about why and how these tumors persist for extended periods of time and then evolve to malignancy. The discovery of cancer stem cells (CSCs) in human tumors challenges our current understanding of tumor recurrence, drug resistance, and metastasis, and opens up new research directions on how cancer cells are capable of switching from dormancy to malignancy. Although overlapping molecules and pathways have been reported to regulate the stem-like phenotype of CSCs and metastasis, accumulated evidence has suggested additional clonal diversity within the stem-like cancer cell subpopulation. This review will describe the current hypothesis linking CSCs and metastasis and summarize mechanisms important for metastatic CSCs to re-initiate tumors in the secondary sites. A better understanding of CSCs' contribution to clinical tumor dormancy and metastasis will provide new therapeutic revenues to eradicate metastatic tumors and significantly reduce the mortality of cancer patients.
Patel, Purvi; Chen, Emily I.
New entrance shade design for SIRTF
NASA Technical Reports Server (NTRS)
A new design for the entrance shade for the Space Infrared Telescope Facility (SIRTF) is presented. The evolution of the entrance shade began with a simple frustum, symmetrical about the telescope axis, when SIRTF was expected to be Shuttle-attached. With the change to a free-flying SIRTF this frustum was cut off at an angle. The telescope will be operated so that whenever not in the earth's shadow the high side is kept toward the sun. However, the entrance shade interior itself will be so warm that the optics, including the secondary mirror and its mechanisms and support structure, will be restricted to the rear part of the barrel, termed the aftbaffle, which is shaded from the interior of the entrance shade by the forebaffle. This is best accomplished by the most recent design in which the axis of the entrance shade is offset from the telescope axis. This results in a shorter entrance shade, shorter forebaffle, and a shaded region within the barrel which is symmetrical about the telescope axis. All of these are advantageous.
Davis, Paul K.
Foamy Virus Budding and Release
Like all other viruses, a successful egress of functional particles from infected cells is a prerequisite for foamy virus (FV) spread within the host. The budding process of FVs involves steps, which are shared by other retroviruses, such as interaction of the capsid protein with components of cellular vacuolar protein sorting (Vps) machinery via late domains identified in some FV capsid proteins. Additionally, there are features of the FV budding strategy quite unique to the spumaretroviruses. This includes secretion of non-infectious subviral particles and a strict dependence on capsid-glycoprotein interaction for release of infectious virions from the cells. Virus-like particle release is not possible since FV capsid proteins lack a membrane-targeting signal. It is noteworthy that in experimental systems, the important capsid-glycoprotein interaction could be bypassed by fusing heterologous membrane-targeting signals to the capsid protein, thus enabling glycoprotein-independent egress. Aside from that, other systems have been developed to enable envelopment of FV capsids by heterologous Env proteins. In this review article, we will summarize the current knowledge on FV budding, the viral components and their domains involved as well as alternative and artificial ways to promote budding of FV particle structures, a feature important for alteration of target tissue tropism of FV-based gene transfer systems.
Hutter, Sylvia; Zurnic, Irena; Lindemann, Dirk
Bacterial Persister Cell Formation and Dormancy
Bacterial cells may escape the effects of antibiotics without undergoing genetic change; these cells are known as persisters. Unlike resistant cells that grow in the presence of antibiotics, persister cells do not grow in the presence of antibiotics. These persister cells are a small fraction of exponentially growing cells (due to carryover from the inoculum) but become a significant fraction in the stationary phase and in biofilms (up to 1%). Critically, persister cells may be a major cause of chronic infections. The mechanism of persister cell formation is not well understood, and even the metabolic state of these cells is debated. Here, we review studies relevant to the formation of persister cells and their metabolic state and conclude that the best model for persister cells is still dormancy, with the latest mechanistic studies shedding light on how cells reach this dormant state.
Knabel, Stephen J.; Kwan, Brian W.
Bacterial persister cell formation and dormancy.
Bacterial cells may escape the effects of antibiotics without undergoing genetic change; these cells are known as persisters. Unlike resistant cells that grow in the presence of antibiotics, persister cells do not grow in the presence of antibiotics. These persister cells are a small fraction of exponentially growing cells (due to carryover from the inoculum) but become a significant fraction in the stationary phase and in biofilms (up to 1%). Critically, persister cells may be a major cause of chronic infections. The mechanism of persister cell formation is not well understood, and even the metabolic state of these cells is debated. Here, we review studies relevant to the formation of persister cells and their metabolic state and conclude that the best model for persister cells is still dormancy, with the latest mechanistic studies shedding light on how cells reach this dormant state. PMID:24038684
Wood, Thomas K; Knabel, Stephen J; Kwan, Brian W
The perivascular niche regulates breast tumor dormancy
In a significant fraction of breast cancer patients, distant metastases emerge after years or even decades of latency. How disseminated tumor cells (DTCs) are kept dormant, and what 'wakes them up', are fundamental problems in tumor biology. To address these questions, we utilized metastasis assays in mice to show that dormant DTCs reside upon microvasculature of lung, bone marrow and brain. We then engineered organotypic microvascular niches to determine whether endothelial cells directly influence breast cancer cell (BCC) growth. These models demonstrated that endothelial-derived thrombospondin-1 induces sustained BCC quiescence. This suppressive cue was lost in sprouting neovasculature; time-lapse analysis showed that sprouting vessels not only permit, but accelerate BCC outgrowth. We confirmed this surprising result in dormancy models and in zebrafish, and identified active TGF-?1 and periostin as tumor-promoting, endothelial tip cell-derived factors. Our work reveals that stable microvasculature constitutes a 'dormant niche,' whereas sprouting neovasculature sparks micrometastatic outgrowth.
Peinado, Hector; Mori, Hidetoshi; Matei, Irina R.; Evason, Kimberley J.; Brazier, Helene; Almeida, Dena; Koller, Antonius; Hajjar, Katherine A.; Stainier, Didier Y.R.; Chen, Emily I.; Lyden, David
Bud4 mediates the cell-type-specific assembly of the axial landmark in budding yeast
Summary Cell polarization occurs along a single axis that is generally determined by a spatial cue. Cells of the budding yeast Saccharomyces cerevisiae select a site for polarized growth in a specific pattern depending on cell type. Haploid a and ? cells bud in the axial budding pattern, which depends on a transient marker and requires proteins Bud3, Bud4, Axl1 and Axl2. Here, we report that Bud4 functions as a platform that mediates the ordered assembly of the axial landmark at the division site during M and early G1 phase. Whereas Bud4 associates with Bud3 in all cell types and in the absence of Axl1 or Axl2, Bud4 interacts with Axl1 and Axl2 mainly in haploid cells and only in the presence of all other components of the landmark. Bud4 can bind to GTP or GDP, and a GTP-binding-defective Bud4 fails to interact with Axl1 in vitro. The same bud4 mutation leads to mis-localization of Axl1 and disrupts the axial budding pattern, indicating that GTP binding to Bud4 is important for its role in bud-site selection. We also show the cell-type-specific association of the axial landmark with Bud5, a GDP/GTP exchange factor for Rsr1. Despite their expression in all cell types, Bud4 and Axl2 associate with Bud5 specifically in haploid cells and in the presence of Axl1, whose expression is limited to a and ? cells. Together, our findings suggest that Bud4 plays a critical role in the assembly of the axial landmark and its link to the Rsr1 GTPase module.
Kang, Pil Jung; Angerman, Elizabeth; Jung, Chan-Hun; Park, Hay-Oak
Coupling of septins to the axial landmark by Bud4 in budding yeast
Summary Cells of the budding yeast Saccharomyces cerevisiae select a site for polarized growth in a specific pattern that depends on their cell type. Haploid a and ? cells bud in the axial budding pattern, which requires assembly of a landmark that includes the Bud4 protein. To understand how an axial bud site is established, we performed a structure–function analysis of Bud4. Bud4 contains DUF1709 (domain of unknown function), which is similar to a part of the anillin-homology domain, and a putative Pleckstrin homology (PH) domain near to its C terminus. Although its localization depends on septins, a conserved family of GTP-binding proteins, Bud4 is necessary for the stable inheritance of septin rings during cell division. Although some anillins interact directly with septins, we find that neither DUF1709 nor the PH domain is necessary for targeting Bud4 to the mother-bud neck. Instead, this C-terminal region is crucial for association of Bud4 with Bud3 and other components of the axial landmark. Remarkably, septins colocalize with Bud4 mutant proteins that lack these C-terminal domains, forming an arc or a single ring instead of a double ring during and after cytokinesis. Interestingly, overexpression of Bud4 also induces formation of extra Bud4 rings and arcs that are associated with septins. Analyses of a series of bud4 truncation mutants suggest that at least two domains in the central region play a redundant role in targeting Bud4 to the mother-bud neck and are thus likely to interact with septins. Taken together, these results indicate that Bud4 functions as a platform that links septins to the axial landmark.
Kang, Pil Jung; Hood-DeGrenier, Jennifer K.; Park, Hay-Oak
Cyclic di-GMP mediates Mycobacterium tuberculosis dormancy and pathogenecity.
Dormancy of Mycobacterium tuberculosis is likely to be a major cause of extended chemotherapeutic regimens and wide prevalence of tuberculosis. The molecular mechanisms underlying M. tuberculosis dormancy are not well understood. In this study, single-copy genes responsible for synthesis (dgc) and degradation (pde) of the ubiquitous bacterial second messenger, cyclic di-GMP (c-di-GMP), were deleted in the virulent M. tuberculosis strain H37Rv to generate dgc(mut) and ?pde, respectively. Under aerobic growth conditions, the two mutants and wild-type cells showed similar phenotypes. However, dgc(mut) and ?pde exhibited increased and reduced dormancy, respectively, in both anaerobiosis-triggered and vitamin C-triggered in vitro dormancy models, as determined by survival and growth recovery from dormancy. The transcriptomes of aerobic cultures of dgc(mut) and wild-type H37Rv exhibited no difference, whereas those of anaerobic cultures showed a significant difference with 61 genes that are not a part of the dosR regulon. Furthermore, ?pde but not dgc(mut) showed decreased infectivity with human THP-1 cells. ?pde also showed attenuated pathogenicity in a C57BL/6 mouse infection model. These findings are explained by c-di-GMP-mediated signaling negatively regulating M. tuberculosis dormancy and pathogenicity. PMID:24080120
Hong, Yuzhi; Zhou, Xiaodan; Fang, Haihong; Yu, Dan; Li, Chuanyou; Sun, Baolin
Using Generic Data to Establish Dormancy Failure Rates
Many hardware items are dormant prior to being operated. The dormant period might be especially long, for example during missions to the moon or Mars. In missions with long dormant periods the risk incurred during dormancy can exceed the active risk contribution. Probabilistic Risk Assessments (PRAs) need to account for the dormant risk contribution as well as the active contribution. A typical method for calculating a dormant failure rate is to multiply the active failure rate by a constant, the dormancy factor. For example, some practitioners use a heuristic and divide the active failure rate by 30 to obtain an estimate of the dormant failure rate. To obtain a more empirical estimate of the dormancy factor, this paper uses the recently updated database NPRD-2011 [1] to arrive at a set of distributions for the dormancy factor. The resulting dormancy factor distributions are significantly different depending on whether the item is electrical, mechanical, or electro-mechanical. Additionally, this paper will show that using a heuristic constant fails to capture the uncertainty of the possible dormancy factors.
Reistle, Bruce
Quantitative analysis of taste bud cell numbers in fungiform and soft palate taste buds of mice.
Mammalian taste bud cells (TBCs) consist of several cell types equipped with different taste receptor molecules, and hence the ratio of cell types in a taste bud constitutes the taste responses of the taste bud. Here we show that the population of immunohistochemically identified cell types per taste bud is proportional to the number of total TBCs in the taste bud or the area of the taste bud in fungiform papillae, and that the proportions differ among cell types. This result is applicable to soft palate taste buds. However, the density of almost all cell types, the population of cell types divided by the area of the respective taste buds, is significantly higher in soft palates. These results suggest that the turnover of TBCs is regulated to keep the ratio of each cell type constant, and that taste responsiveness is different between fungiform and soft palate taste buds. PMID:20971092
Ohtubo, Yoshitaka; Yoshii, Kiyonori
An Entrance Region Mass Transfer Experiment.
This paper describes an experiment designed to reveal the consequences of the development of a concentration boundary layer. The rate of a mass transfer limited electrochemical reaction is measured and used to obtain the dependence of average Sherwood number on Reynolds number and entrance length. (Author/BB)
Youngquist, G. R.
College Entrance Guide for American Students Overseas.
Comprehensive information about types of postsecondary institutions and the entrance process is presented, with special consideration given to the special needs of American students overseas. The guidelines may also be useful to non-Americans educated in overseas schools who seek further study in the United States. Advantages and drawbacks to…
College Entrance Examination Board, New York, NY.
Effects of Entrance Loss on Harbor Oscillations.
By assuming a head loss across the harbor entrance the wave-induced response in a rectangular model harbor is studied theoretically. The loss is assumed to be quadratic in local velocity with a constant friction coefficient. Bottom and side-wall dissipati...
U. Unluata C. C. Mei
Abscisic Acid Levels and Seed Dormancy
Dormant seeds from Fraxinus species require cold-temperature after-ripening prior to germination. Earlier, we found that abscisic acid (ABA) will inhibit germination of excised nondormant embryos and that this can be reversed with a combination of gibberellic acid and kinetin. Using Milborrow's quantitative "racemate dilution" method the ABA concentration in 3 types of Fraxinus seed and pericarp were determined. While ABA was present in all tissues, the highest concentration was found in the seed and pericarp of dormant F. americana. During the chilling treatment of F. americana the ABA levels decreased 37% in the pericarp and 68% in the seed. The ABA concentration of the seed of the nondormant species, F. ornus, is as low as that found in F. americana seeds after cold treatment. Experiments with exogenously added ABA solutions indicate that it is unlikely that the ABA in the pericarp functions in the regulation of seed dormancy. However, the ABA in the seed does seem to have a regulatory role in germination. Images
Sondheimer, E.; Tzou, D. S.; Galson, Eva C.
Uveal melanoma dormancy: an acceptable clinical endpoint?
Uveal melanoma is a rare but life-threatening malignancy. Over the past decades, the morbidity of uveal melanoma has been markedly reduced as a result of advances in the diagnostic ability to detect smaller tumors at an earlier stage. This has allowed for the use of more conservative treatments, avoiding enucleation. Mortality, however, has remained unchanged. This indicates that life expectancy is independent of local tumor control. Metastatic disease, the leading cause of death, is usually diagnosed many years later, despite successful treatment of the primary tumor, and at a late stage, when no effective therapy is available. These observations suggest that the disease was already disseminated at the time of tumor diagnosis. The detection of circulating malignant cells in the bloodstream of patients at different time points in the course of the disease supports this observation. Tumor dormancy has been considered as the leading theory for this intriguing delayed appearance of metastasis. Recent knowledge gained about the biological behavior of uveal melanoma as well as novel potential therapeutic targets are presented in this review. PMID:22895346
Blanco, Paula L; Lim, Li Anne; Miyamoto, Cristina; Burnier, Miguel N
The role of metastasis suppressor genes in metastatic dormancy
Metastasis suppressor genes (MSGs) are defined by their ability to inhibit overt metastasis in a secondary organ without affecting tumor growth at the primary site. Over 20 MSGs have been confirmed in vivo. This class of genes is only unified by their capacity to suppress metastasis, as they encode for proteins with a wide range of biochemical activities that are components of a variety of signaling pathways. In addition, metastasis suppressors impinge upon different stages of the metastatic cascade to manifest their suppressive effects. The MSGs KISS1, KAI1, MKK4/7 and Nm23-H1 promote tumor dormancy at the metastatic site, since tumor cells with induced expression of these MSGs disseminate, but do not form overt metastases in the secondary organ throughout the duration of a metastasis assay. Evidence suggests that KISS1 triggers dormancy in solitary, metastatic tumor cells by causing growth arrest of solitary cells at the secondary site. KAI1 induces growth arrest prior to extravasation by binding a vascular endothelial cell surface marker. MKK4, MKK7 and Nm23-H1 appear to promote dormancy of micrometastatic colonies, after disseminated tumor cells have undergone several rounds of proliferation. Other MSGs may also function in tumor dormancy, but so far their role has not been fully elucidated. Therapeutic approaches that either mimic the effects of MSGs or re-establish MSG expression in metastatic lesions may hold promise for the establishment or maintenance of dormancy.
Dormancy contributes to the maintenance of microbial diversity.
Dormancy is a bet-hedging strategy used by a variety of organisms to overcome unfavorable environmental conditions. By entering a reversible state of low metabolic activity, dormant individuals become members of a seed bank, which can determine community dynamics in future generations. Although microbiologists have documented dormancy in both clinical and natural settings, the importance of seed banks for the diversity and functioning of microbial communities remains untested. Here, we develop a theoretical model demonstrating that microbial communities are structured by environmental cues that trigger dormancy. A molecular survey of lake ecosystems revealed that dormancy plays a more important role in shaping bacterial communities than eukaryotic microbial communities. The proportion of dormant bacteria was relatively low in productive ecosystems but accounted for up to 40% of taxon richness in nutrient-poor systems. Our simulations and empirical data suggest that regional environmental cues and dormancy synchronize the composition of active communities across the landscape while decoupling active microbes from the total community at local scales. Furthermore, we observed that rare bacterial taxa were disproportionately active relative to common bacterial taxa, suggesting that microbial rank-abundance curves are more dynamic than previously considered. We propose that repeated transitions to and from the seed bank may help maintain the high levels of microbial biodiversity that are observed in nearly all ecosystems. PMID:20231463
Jones, Stuart E; Lennon, Jay T
Phenotypic Selection for Dormancy Introduced a Set of Adaptive Haplotypes From Weedy Into Cultivated Rice
Association of seed dormancy with shattering, awn, and black hull and red pericarp colors enhances survival of wild and weedy species, but challenges the use of dormancy genes in breeding varieties resistant to preharvest sprouting. A phenotypic selection and recurrent backcrossing technique was used to introduce dormancy genes from a wild-like weedy rice to a breeding line to determine their
Xing-You Gu; Shahryar F. Kianian; Michael E. Foley
Seasonal conditions influence dormancy and preharvest sprouting tolerance of wheat ( Triticum aestivum L.) in the field
Preharvest sprouting occurs following rainfall after maturity and reduces grain quality and value. Dormancy at maturity is a trait frequently used by wheat breeders to improve tolerance to sprouting. To determine the environmental influence on the predicative relationship between dormancy at maturity and improved preharvest sprouting tolerance, dormancy (germination index) at maturity and grain quality (falling number) at maturity and
T. B. Biddulph; J. A. Plummer; T. L. Setter; D. J. Mares
Influence of high temperature and terminal moisture stress on dormancy in wheat ( Triticum aestivum L.)
Preharvest sprouting is common in cereals that lack grain dormancy if maturing grain is exposed to rain. Over three successive seasons wheat genotypes with a range of dormancy levels, were exposed to moisture stress and periods of high temperature stress (>30°C) in controlled field trials. Dormancy assessments were based on a germination index of hand threshed grain throughout grain filling.
Thomas B. Biddulph; Julie A. Plummer; Tim L. Setter; Daryl J. Mares
Rapid and Effective Germination Methods for Overcoming Seed Dormancy in Annual Canarygrass
Mediterranean climates (P. aquatica) (Carlson et al., 1996). Dormancy in pedigreed Phalaris seed can lead to unsatisfactory Seed dormancy, thetemporary failure of aviable seed germination in seed testing. The objective was to determine the effec- to germinate (Simpson, 1990), reduces germination per- tiveness of recommended germination methods in overcoming seed dormancy in annual canarygrass (P. canariensis L.). In 2003, 'CDC
M. A. Matus-Cádiz; P. Hucl
Hydrothermal time analysis of seed dormancy in true (botanical) potato seeds
As seed dormancy is released within a seed population, both the rate and percentage of germina- tion increase progressively with increasing dose of a dormancy-breaking treatment or condition. Popu- lation-based models can account for this behaviour on the basis of shifting response thresholds as dormancy is alleviated. In particular, hydrothermal time analysis of germination sensitivity to water potential (C) and
Kent J. Bradford; Veria Alvarado
A novel preclinical murine model of immune-mediated metastatic dormancy
The mechanisms underlying cancer dormancy are poorly understood. We have developed a preclinical murine model in which immunosurveillance restrains spontaneous metastases in permanent dormancy. The model faithfully recapitulates human metastatic dormancy and may be useful to decipher the immune mechanisms constraining disease progression, thereby facilitating the development of novel immunotherapeutic approaches to control metastatic disease.
Romero, Irene; Garrido, Federico; Garcia-Lora, Angel M
57. POWDER MAGAZINE, DETAIL VIEW OF NORTHEAST FRONT ENTRANCE TO ACESS PASSAGE TO MAGAZINES FROM INTERIOR OF MAGAZINE SHOWING VENTILATION WINDOWS (BARRED) FLANKING ENTRANCE DOOR (OPEN). NOTE ACCESS PASSAGE TO ADJOING MAGAZINE. - Fort Monroe, Fortress, Hampton, Hampton, VA
SLAC divertor channel entrance thermal stress analysis
X-ray beams emerging from the new SLAC electron-positron storage ring (PEP) impinge on the entrance to tangential divertor channels causing highly localized heating in the channel structure. Analyses were completed to determine the temperatures and thermally-induced stresses due to this heating. These parts are cooled with water flowing axially over them at 30/sup 0/C. The current design and operating conditions should result in the entrance to the new divertor channel operating at a peak temperature of 123/sup 0/C with a peak thermal stress at 91% of yield. Any micro-cracks that form due to thermally-induced stresses should not propagate to the coolant wall nor form a path for the coolant to leak into the storage ring vacuum. 34 figs., 4 tabs.
Johnson, G.L.; Stein, W.; Lu, S.C.; Riddle, R.A.
Tumour dormancy and clinical implications in breast cancer
The aim of adjuvant therapy in breast cancer is to reduce the risk of recurrence. Some patients develop metastases many years after apparently successful treatment of their primary cancer. Tumour dormancy may explain the long time between initial diagnosis and treatment of cancer, and occurrence of relapse. The regulation of the switch from clinical dormancy to cancer regrowth in locoregional and distant sites is poorly understood. In this review, we report some data supporting the existence of various factors that may explain cancer dormancy including genetic and epigenetic changes, angiogenic switch, microenvironment, and immunosurveillance. A better definition and understanding of these factors should allow the identification of patients at high risk of relapse and to develop new therapeutic strategies in order to improve prognosis.
Gelao, L; Criscitiello, C; Fumagalli, L; Locatelli, M; Manunta, S; Esposito, A; Minchella, I; Goldhirsch, A; Curigliano, G
Rapid evolution of sex frequency and dormancy as hydroperiod adaptations.
Dormancy can serve as an adaptation to persist in variable habitats and often is coupled with sex. In cyclically parthenogenetic rotifers, an asexual phase enables rapid population growth, whereas sex results in diapausing embryos capable of tolerating desiccation. Few studies have experimentally tested whether sex-dormancy associations in temporary waters reflect evolution in response to the short hydroperiod selecting for diapause ability. Here, we demonstrate evolution of higher propensity for sex and dormancy in ephemeral rotifer cultures mimicking temporary ponds, and lower propensity in permanent cultures. Results are consistent with rapid evolution, with evolutionary changes occurring in a short timeframe (385 days, ? 84 generations). We also provide insight into mechanisms for rapid evolution in basal metazoans, discussing potential roles of new mutations, recombination and clonal selection. PMID:22994805
Smith, H A; Snell, T W
Release of Lateral Buds from Apical Dominance
IT has been shown with isolated stem sections bearing a single bud that the development of this bud can be inhibited by indolyl-3-acetic acid (IAA) or other auxins, and this inhibition released by kinetin1. The concentrations of IAA needed are physiological, and the whole phenomenon appears identical with that of normal apical dominance. Nevertheless, the question remains as to whether
Tsvi Sachs; Kenneth V. Thimann
Inhibition of Tiller Bud Outgrowth in the tin Mutant of Wheat Is Associated with Precocious Internode Development[W
Tillering (branching) is a major yield component and, therefore, a target for improving the yield of crops. However, tillering is regulated by complex interactions of endogenous and environmental signals, and the knowledge required to achieve optimal tiller number through genetic and agronomic means is still lacking. Regulatory mechanisms may be revealed through physiological and molecular characterization of naturally occurring and induced tillering mutants in the major crops. Here we characterize a reduced tillering (tin, for tiller inhibition) mutant of wheat (Triticum aestivum). The reduced tillering in tin is due to early cessation of tiller bud outgrowth during the transition of the shoot apex from the vegetative to the reproductive stage. There was no observed difference in the development of the main stem shoot apex between tin and the wild type. However, tin initiated internode development earlier and, unlike the wild type, the basal internodes in tin were solid rather than hollow. We hypothesize that tin represents a novel type of reduced tillering mutant associated with precocious internode elongation that diverts sucrose (Suc) away from developing tillers. Consistent with this hypothesis, we have observed upregulation of a gene induced by Suc starvation, downregulation of a Suc-inducible gene, and a reduced Suc content in dormant tin buds. The increased expression of the wheat Dormancy-associated (DRM1-like) and Teosinte Branched1 (TB1-like) genes and the reduced expression of cell cycle genes also indicate bud dormancy in tin. These results highlight the significance of Suc in shoot branching and the possibility of optimizing tillering by manipulating the timing of internode elongation.
Kebrom, Tesfamichael H.; Chandler, Peter M.; Swain, Steve M.; King, Rod W.; Richards, Richard A.; Spielmeyer, Wolfgang
Clinal Variation in phyB2, a Candidate Gene for Day-Length-Induced Growth Cessation and Bud Set, Across a Latitudinal Gradient in European Aspen (Populus tremula)
The initiation of growth cessation and dormancy represents a critical ecological and evolutionary trade-off between survival and growth in most forest trees. The most important environmental cue regulating the initiation of dormancy is a shortening of the photoperiod and phytochrome genes have been implicated in short-day-induced bud set and growth cessation in Populus. We characterized patterns of DNA sequence variation at the putative candidate gene phyB2 in 4 populations of European aspen (Populus tremula) and scored single-nucleotide polymorphisms in an additional 12 populations collected along a latitudinal gradient in Sweden. We also measured bud set from a subset of these trees in a growth chamber experiment. Buds set showed significant clinal variation with latitude, explaining ?90% of the population variation in bud set. A sliding-window scan of phyB2 identified six putative regions with enhanced population differentiation and four SNPs showed significant clinal variation. The clinal variation at individual SNPs is suggestive of an adaptive response in phyB2 to local photoperiodic conditions. Three of four SNPs showing clinal variation were located in regions with excessive genetic differentiation, demonstrating that searching for regions of high genetic differentiation can be useful for identifying sites putatively involved in local adaptation.
Ingvarsson, Par K.; Garcia, M. Victoria; Hall, David; Luquez, Virginia; Jansson, Stefan
Are dormant plants hedging their bets? Demographic consequences of prolonged dormancy in variable environments.
During the growing season, some individuals in perennial plant populations may remain alive belowground while others emerge. This phenomenon, known as prolonged dormancy, seems maladaptive, because prolonged dormancy delays growth and reproduction. However, prolonged dormancy may offer the benefit of safety while belowground, leading to the hypothesis that prolonged dormancy is a bet-hedging strategy. We evaluated this hypothesis using a 25-year demographic study of Astragalus scaphoides, an iteroparous perennial plant. First, we determined the relationship between prolonged dormancy and fitness using data from individuals in our population. This analysis showed that prolonged dormancy decreased arithmetic mean fitness and reduced variance in fitness. Geometric mean fitness was maximized at intermediate levels of prolonged dormancy. Empirical patterns of lifetime reproductive success confirm this relationship. We also compared fitness of plants in our population to hypothetical plants without prolonged dormancy, which generally revealed benefits of prolonged dormancy, even if plants could forgo prolonged dormancy without costs to other vital rates. Therefore, prolonged dormancy may indeed function as a bet-hedging strategy, but the benefits of remaining belowground outweigh the costs only for a subset of individuals. Bet hedging has been demonstrated in plants with simple life histories, such as annuals and monocarpic perennials; we present evidence that bet hedging may be important for plants with more complex life histories. PMID:22322220
Gremer, Jennifer R; Crone, Elizabeth E; Lesica, Peter
DELLA-mediated cotyledon expansion breaks coat-imposed seed dormancy.
Seed dormancy is a key adaptive trait in plants responsible for the soil seed bank. The long established hormone-balance theory describes the antagonistic roles of the dormancy promoting plant hormone abscisic acid (ABA), and the germination promoting hormone gibberellin (GA) in dormancy control. Light, temperature, and other dormancy-breaking signals function to modulate the synthesis and perception of these hormones in the seed. However, the way in which these hormones control dormancy in the imbibed seed remains unknown. Here, we show that the DELLA protein regulators of the GA response are required for dormancy and describe a model through which hormone signal integration and dormancy regulation is achieved. We demonstrate that cotyledon expansion precedes radicle emergence during Arabidopsis seed germination and that a striking correlation exists between final seedling cotyledon size and seed dormancy in the DELLA mutants. Furthermore, twelve previously characterized seed-dormancy mutants are also defective in the control of cotyledon size in a manner consistent with their effect on germination potential. We propose that DELLA-mediated, light-, temperature-, and hormone-responsive cotyledon expansion prior to radicle emergence overcomes dormancy imposed by the seed coat and underlies seed-dormancy control in Arabidopsis. PMID:17141619
Penfield, Steven; Gilday, Alison D; Halliday, Karen J; Graham, Ian A
Summer dormancy in edible dormice ( Glis glis) without energetic constraints
Average longevity in free-living edible dormice ( Glis glis) can reach 9 years, which is extremely high for a small rodent. This remarkable life span has been related to a peculiar life history strategy and the rarity of reproductive bouts in these seed eaters. Most females (96%) reproduce only once or twice in their lifetime, predominantly during years of mast seeding of, e.g., beech, but entire populations can skip reproduction in years of low seed availability. Surprisingly, in non-reproductive years, large fractions of populations apparently vanished and were never captured above ground. Therefore, we determined the duration of above-ground activity, and body temperature profiles in a subset of animals, of dormice under semi-natural conditions in outdoor enclosures. We found that non-reproductive dormice returned to dormancy in underground burrows throughout summer after active seasons as short as <2 weeks. Thus, animals spent up to >10 months per year in dormancy. This exceeds dormancy duration of any other mammal under natural conditions. Summer dormancy was not caused by energy constraints, as it occurred in animals in good condition, fed ad libitum and without climatic stress. We suggest that almost year-round torpor has evolved as a strategy to escape birds of prey, the major predators of this arboreal mammal. This unique predator-avoidance strategy clearly helps in explaining the unusually high longevity of dormice.
Bieber, Claudia; Ruf, Thomas
Hormonal Regulation of Dormancy in Developing Sorghum Seeds
~~ lhe role of abscisic acid (ABA) and gibberellic acid (CA) in deter- mining the dormancy level of developing sorghum (Sorghum bicolor (L.) Moench.) seeds from varieties presenting contrasting preharvest sprouting behavior (Redland 82, susceptible; IS 9530, resistant) was investigated. Panicles from both varieties were sprayed soon after pollination with fluridone or paclobutrazol to inhibit ABA and CA synthesis, respectively.
Haydée S. Steinbach; Roberto L. Benech-Arnold; Rodolfo A. Sánchez
Gibberellic Acid Breaks Dormancy and Hastens Germination of Creeping Sage.
Creeping sage (Salvia sonomensis Greene), a semi-shrub, is useful for plantings to reduce fire hazard and to stabilize soil. The most effective, practical, and lasting technique to break seed dormancy was a soaking in gibberellic acid under constant agita...
E. C. Nord L. E. Gunter S. A. Graham
Factors affecting the induction of secondary dormancy in lettuce.
The relationship between the temperature at which germination of 50% of the seeds is inhibited in the light (GT(50) Light) and secondary dormancy was investigated in three cultivars of Lactuca sativa L. Seeds were incubated for varying periods under non-germinating conditions and subsequent germination in response to red light (R) was determined over a wide range of temperatures. Dark incubation at 32 C reduced the GT(50) Light of cv. New York but did not affect germination at temperatures below 24 C. Dark, 32 C incubation had no effect on the GT(50) Light of cv. Great Lakes. In cv. Grand Rapids, dark incubation at 15, 24, 32, or 35 C initially reduced the GT(50) Light. However, longer incubations induced a secondary dormancy, i.e., the seeds became unable to germinate at all temperatures in response to R given after the high temperature incubation. A single exposure to R at the beginning of a 32 C incubation slowed the induction of secondary dormancy. Repeated exposures to R prevented the induction of secondary dormancy, but did not prevent a decline in the GT(50) Light. GA(3) mimicked the effect of repeated R.The differences in the germination behavior of the three cultivars suggest that there may be qualitative differences in the germination mechanism of these cultivars. This research demonstrates the significance of monitoring germination at a range of temperatures to avoid misinterpretation of the data. PMID:16661841
Kristie, D N; Bassi, P K; Spencer, M S
Seed Coat Dormancy in Two Species of Grevillea(Proteaceae)
The role played by the seed coat in seed dormancy of Grevillea linearifolia(Cav.) Druce and G. wilsonii(A. Cunn.) was tested by a series of manipulations in which the seed coat was dissected and removed, dissected and returned to the decoated seed, or dissected, removed and given a heat shock, and returned to the decoated seed. Germination of intact seeds of
E. Charles Morris; Anle Tieu; Kingsley Dixon
Microbial seed banks: the ecological and evolutionary implications of dormancy
Dormancy is a bet-hedging strategy used by a wide range of taxa, including microorganisms. It refers to an organism's ability to enter a reversible state of low metabolic activity when faced with unfavourable environmental conditions. Dormant microorganisms generate a seed bank, which comprises individuals that are capable of being resuscitated following environmental change. In this Review, we highlight mechanisms that
Stuart E. Jones; Jay T. Lennon
Perspectives of biotechnologies based on dormancy phenomenon for space researches
Long term space missions will require a renewable source of food and an efficient method to recycle oxygen Plants especially aquatic micro algae provide an obvious solution to these problems However long duration plant growth and reproduction in space that is necessary for transportation of a control ecological life support system CELSS from Earth to other planets are problematic The introduction of heterotrophs in space CELSS is a more formidable problem as the absence of gravity creates additional difficulties for their life Dormancy phenomenon protected a great many animals and plants in harsh environmental conditions within a special resting phases of life cycle lasting from months up to hundred years This phenomenon can be quite perspective as a tool to overcome difficulties with CELSS transportation in space missions Cryptobiotic stages of microbes fungi unicellular algae and protists can survive in open space conditions that is important for interplanetary quarantine and biological security inside spacecraft Searching for life outside the Earth at such planet like Mars with extremely variable environment should be oriented on dormancy as crucial phases of a life cycle in such organisms Five major research programs aimed on study dormancy phenomenon for exobiology purposes and creation of new biotechnologies are discussed List of species candidate components of CELSS with dormancy in their life cycle used in space experiments at the Russian segment of International Space Station now includes 26 species from bacteria to fish The
Alekseev, V.; Sychev, V.; Layus, D.; Levinsky, M.; Novikova, N.; Zakhodnova, T.
Summer dormancy in edible dormice (Glis glis) without energetic constraints.
Average longevity in free-living edible dormice (Glis glis) can reach 9 years, which is extremely high for a small rodent. This remarkable life span has been related to a peculiar life history strategy and the rarity of reproductive bouts in these seed eaters. Most females (96%) reproduce only once or twice in their lifetime, predominantly during years of mast seeding of, e.g., beech, but entire populations can skip reproduction in years of low seed availability. Surprisingly, in non-reproductive years, large fractions of populations apparently vanished and were never captured above ground. Therefore, we determined the duration of above-ground activity, and body temperature profiles in a subset of animals, of dormice under semi-natural conditions in outdoor enclosures. We found that non-reproductive dormice returned to dormancy in underground burrows throughout summer after active seasons as short as <2 weeks. Thus, animals spent up to >10 months per year in dormancy. This exceeds dormancy duration of any other mammal under natural conditions. Summer dormancy was not caused by energy constraints, as it occurred in animals in good condition, fed ad libitum and without climatic stress. We suggest that almost year-round torpor has evolved as a strategy to escape birds of prey, the major predators of this arboreal mammal. This unique predator-avoidance strategy clearly helps in explaining the unusually high longevity of dormice. PMID:19034404
Mitochondrial Network Size Scaling in Budding Yeast**
Mitochondria must grow with the growing cell to ensure proper cellular physiology and inheritance upon division. We measured the physical size of mitochondrial networks in budding yeast and found that mitochondrial network size increased with increasing cell size and that this scaling relation occurred primarily in the bud. The mitochondria to cell size ratio continually decreased in aging mothers over successive generations. However, regardless of mother age or mitochondrial content, all buds attained the same average ratio. Thus, yeast populations achieve a stable scaling relation between mitochondrial content and cell size despite asymmetry in inheritance.
Rafelski, Susanne M.; Viana, Matheus P.; Zhang, Yi; Chan, Yee-Hung M.; Thorn, Kurt S.; Yam, Phoebe; Fung, Jennifer C.; Li, Hao; Costa, Luciano da F.; Marshall, Wallace F.
Parallel processing in mammalian taste buds?
There is emerging evidence that two parallel lines of gustatory information are generated in taste buds. One pathway leads to higher cortical centers and is involved in discriminating basic taste qualities (sweet, bitter, sour, salty, umami) and perceiving flavors. The other pathway may conduct information involved in physiological reflexes such as swallowing, salivation, and cephalic phase digestion. If this notion is true, the existence of two populations of taste bud cells that have different functional characteristics may lie at the origins of the two pathways. This speculative concept is explored in this review of taste signal processing in mammalian taste buds.
Roper, Stephen D.
Dormancy-associated MADS genes from the EVG locus of peach [Prunus persica (L.) Batsch] have distinct seasonal and photoperiodic expression patterns.
Mapping and sequencing of the non-dormant evg mutant in peach [Prunus persica (L.) Batsch] identified six tandem-arrayed DAM (dormancy-associated MADS-box) genes as candidates for regulating growth cessation and terminal bud formation. To narrow the list of candidate genes, an attempt was made to associate bud phenology with the seasonal and environmental patterns of expression of the candidates in wild-type trees. The expression of the six peach DAM genes at the EVG locus of peach was characterized throughout an annual growing cycle in the field, and under controlled conditions in response to a long day-short day photoperiod transition. DAM1, 2, 4, 5, and 6 were responsive to a reduction in photoperiod in controlled conditions and the direction of response correlated with the seasonal timing of expression in field-grown trees. DAM3 did not respond to photoperiod and may be regulated by chilling temperatures. The DAM genes in peach appear to have at least four distinct patterns of expression. DAM1, 2, and 4 are temporally associated with seasonal elongation cessation and bud formation and are the most likely candidates for control of the evg phenotype. PMID:19553369
Li, Zhigang; Reighard, Gregory Lynn; Abbott, Albert Glenn; Bielenberg, Douglas Gary
Reconstitution of membrane budding with unilamellar vesicles
Enveloped virus particles select their lipid-protein components and egress by budding from the host cell membranes. The matrix protein of many enveloped viruses has been proposed as a crucial element for viral budding; however, molecular mechanisms behind membrane budding by the matrix protein are yet to be unraveled. Here we describe a set of in vitro functional reconstitution assays that allows quantitative evaluation of both, membrane binding and creation of membrane curvature by the matrix protein isolated from Newcastle Disease Virus. Individual budding events orchestrated by the matrix protein can be resolved in real time. The assays may be applied for direct reconstitution of the on-membrane action of cellular proteins involved in membrane curvature induction upon binding in vivo.
Shnyrova, Anna V.; Zimmerberg, Joshua
BudPro — Budget Projection Software
Agricultural producers need to develop marketing plans. A major component of a marketing plan is an estimate of the price necessary to cover all costs based on expected yields (break-even price). BudPro is designed to help agricultural produc- ers with this estimation. The BudPro for Windows software includes one program for all crops and one for stocker cattle. The software
Stan Bevers; Jackie Smith; David Rempe
Phylogeny of seed dormancy in Convolvulaceae, subfamily Convolvuloideae (Solanales)
Background and Aims The water gap is an important morphoanatomical structure in seeds with physical dormancy (PY). It is an environmental signal detector for dormancy break and the route of water into the non-dormant seed. The Convolvulaceae, which consists of subfamilies Convolvuloideae (11 tribes) and Humbertoideae (one tribe, monotypic Humberteae), is the only family in the asterid clade known to produce seeds with PY. The primary aim of this study was to compare the morphoanatomical characteristics of the water gap in seeds of species in the 11 tribes of the Convolvuloideae and to use this information, and that on seed dormancy and storage behaviour, to construct a phylogenetic tree of seed dormancy for the subfamily. Methods Scanning electron microscopy (SEM) was used to define morphological changes in the hilum area during dormancy break; hand and vibratome sections were taken to describe the anatomy of the water gap, hilum and seed coat; and dye tracking was used to identify the initial route of water entry into the non-dormant seed. Results were compared with a recent cladogram of the family. Key Results Species in nine tribes have (a) layer(s) of palisade cells in the seed coat, a water gap and orthodox storage behaviour. Erycibe (Erycibeae) and Maripa (Maripeae) do not have a palisade layer in the seed coat or a water gap, and are recalcitrant. The hilar fissure is the water gap in relatively basal Cuscuteae, and bulges adjacent to the micropyle serve as the water gap in the Convolvuloideae, Dicranostyloideae (except Maripeae) and the Cardiochlamyeae clades. Seeds from the Convolvuloideae have morphologically prominent bulges demarcated by cell shape in the sclereid layer, whereas the Dicranostyloideae and Cardiochlamyeae have non-prominent bulges demarcated by the number of sub-cell layers. The anatomy and morphology of the hilar pad follow the same pattern. Conclusions PY in the subfamily Convolvuloideae probably evolved in the aseasonal tropics from an ancestor with recalcitrant non-dormant seeds, and it may have arisen as Convolvulaceae radiated to occupy the seasonal tropics. Combinational dormancy may have developed in seeds of some Cuscuta spp. as this genus moved into temperate habitats.
Jayasuriya, K. M. G. Gehan; Baskin, Jerry M.; Geneve, Robert L.; Baskin, Carol C.
INTERIOR VIEW OF ENTRANCE TO LABORATORY, SHOWING HAND-HAMMERED ALUMINUM DOORS AND MARBLE. NOTE ALUMINUM LIGHT FIXTURE - Alcoa Research Laboratory, Freeport Road, New Kensington, Westmoreland County, PA
double hung window details, hall window details, entrance door profiles ...
double hung window details, hall window details, entrance door profiles - Chopawamsic Recreational Demonstration Area - Cabin Camp 1, Help's Quarters, Prince William Forest Park, Triangle, Prince William County, VA
?Cat FACE? SCAR ON LONGLEAF PINE TREE, OVERHILLS HISTORIC ENTRANCE ...
?Cat FACE? SCAR ON LONGLEAF PINE TREE, OVERHILLS HISTORIC ENTRANCE ROAD, FACING NORTHEAST - Overhills, Fort Bragg Military Reservation, Approximately 15 miles NW of Fayetteville, Overhills, Harnett County, NC
4. DETAILED VIEW OF MAIN ENTRANCE ON SOUTHWEST FRONT. VIEW TO NORTHEAST. - Commercial & Industrial Buildings, Farley & Loetscher Manufacturing Company, Factory II, 750 White Street, Dubuque, Dubuque County, IA
Building, north side (original front), detail of original entrance. Camera ...
Building, north side (original front), detail of original entrance. Camera facing south - Naval Supply Center, Broadway Complex, Administration Storehouse, 911 West Broadway, San Diego, San Diego County, CA
Perspective view of east entrance from northeast National Home ...
Perspective view of east entrance from northeast - National Home for Disabled Volunteer Soldiers, Pacific Branch, Mental Health Building, 11301 Wilshire Boulevard, West Los Angeles, Los Angeles County, CA
Detail of main entrance, camera facing southeast Golden Gate ...
Detail of main entrance, camera facing southeast - Golden Gate International Exposition, Palace of Fine and Decorative Arts & Annex, California Avenue, Treasure Island, San Francisco, San Francisco County, CA
Transcriptomics Analysis Identified Candidate Genes Colocalized with Seed Dormancy QTLs in Rice ( Oryza sativa L.)
Rice seed dormancy is an important trait related to the preharvest sprouting resistance of rice and is controlled by a polygene\\u000a network. To identify the genes involved in this process, transcriptome analysis was applied to strong seed dormancy indica\\u000a cultivar N22 and its weak dormancy mutant Q4646. The results showed that 280 genes were significantly upregulated and 244\\u000a genes significantly
Huaide Qin; Fuqing Wu; Kun Xie; Zhijun Cheng; Xiuping Guo; Xin Zhang; Jie Wang; Cailin Lei; Jiulin Wang; Long Mao; Ling Jiang; Jianmin Wan
Genetic and environmental control of dormancy in white-grained wheat ( Triticum aestivum L.)
Grain dormancy in wheat is an important component of resistance to preharvest sprouting and hence an important trait for wheat\\u000a breeders. The significant influence of environment on the dormancy phenotype makes this trait an obvious target for marker-assisted-selection.\\u000a Closely related breeding lines, SUN325B and QT7475, containing a major dormancy QTL derived from AUS1408 located on chromosome\\u000a 4A, but substantially different
Daryl Mares; Judith Rathjen; Kolumbina Mrva; Judy Cheong
A genetic model and molecular markers for wild oat (Avena fatua L.) seed dormancy
Seed dormancy allows weed seeds to persist in agricultural soils. Wild oat (Avena fatua L.) is a major weed of cereal grains and expresses a range of seed dormancy phenotypes. Genetic analysis of wild oat dormancy\\u000a has been complicated by the difficulty of phenotypic classification in segregating populations. Therefore, little is known\\u000a about the nature of the genes that regulate
S. A. Fennimore; W. E. Nyquist; G. E. Shaner; R. W. Doerge; M. E. Foley
Shortening dormancy of seed potatoes by a haulm application of gibberellic acid and storage temperature regimes
In three experiments with cvs Diamant (short dormancy) and Désirée (long dormancy), the effect of a haulm application of gibberellic\\u000a acid (GA) on the dormancy of seed potatoes harvested immature was investigated. Several storage temperature regimes were imposed\\u000a to examine the interaction between GA and storage temperature. The storage regimes included 18 and 28 C continuously, hot\\u000a pre-treatments of different
M. K. van Ittersum; K. Scholte
Habitat preferences as related to the prolonged dormancy of perennial herbs and ferns
Prolonged dormancy (hereafter dormancy), a phenomenon in which a perennial herbaceous plant does not sprout for one or more\\u000a years, is examined. The phenomenon may be more frequent than stated so far and discovery of its role in plant life history\\u000a and performance is still underway. Data from published papers was reviewed and all known species exhibiting dormancy were\\u000a analysed
Margit Reintal; Kadri Tali; Marina Haldna; Tiiu Kull
The evolution of seed dormancy: environmental cues, evolutionary hubs, and diversification of the seed plants.
Seed dormancy, by controlling the timing of germination, can strongly affect plant survival. The kind of seed dormancy, therefore, can influence both population and species-level processes such as colonization, adaptation, speciation, and extinction. We used a dataset comprising over 14 000 taxa in 318 families across the seed plants to test hypotheses on the evolution of different kinds of seed dormancy and their association with lineage diversification. We found morphophysiological dormancy to be the most likely ancestral state of seed plants, suggesting that physiologically regulated dormancy in response to environmental cues was present at the origin of seed plants. Additionally, we found that physiological dormancy (PD), once disassociated from morphological dormancy, acted as an 'evolutionary hub' from which other dormancy classes evolved, and that it was associated with higher rates of lineage diversification via higher speciation rates. The environmental sensitivity provided by dormancy in general, and by PD in particular, appears to be a key trait in the diversification of seed plants. PMID:24684268
Willis, Charles G; Baskin, Carol C; Baskin, Jerry M; Auld, Josh R; Venable, D Lawrence; Cavender-Bares, Jeannine; Donohue, Kathleen; Rubio de Casas, Rafael
Reproductive dormancy in boll-weevil from populations of the midwest of Brazil.
The boll weevil (Anthonomus grandis Boheman) (Coleoptera: Curculionidae) is an introduced pest in Brazil, which in 30 yr has successfully expanded to various eco-regions and became the most important pest of cotton (Gossypium hirsutum, Malvaceae). Given the limited knowledge about the adaptive mechanisms that allowed successful establishment of the pest population in a tropical region, in this work we studied the potential of the Midwest population of boll weevils to enter a reproductive dormancy and identified the importance of the feeding source for induction of dormancy. We investigated morphological and physiological characters as indicators of the dormancy. We also investigated the occurrence of reproductive dormancy in boll weevils populations from cotton farms of the Midwestern region of Brazil during the cotton and noncotton seasons of 2009 and 2010. The studies revealed that boll weevils entered facultative reproductive dormancy; however, unlike what has been observed for boll weevils from temperate and subtropical regions, the hypertrophy of fat body and hexamerin levels did not straightly correlated to reproductive dormancy. The food source and field conditions during early adult development were decisive factor for the induction of reproductive dormancy. The incidence of reproductive dormancy increased progressively as the phenology of cotton plant advanced, reaching approximately 90% at the end of the crop season. During the noncotton season, the boll weevil was predominantly found in reproductive dormancy, especially females; however, there is evidence of use of multiple adaptive strategies to colonize the next harvest. PMID:23448019
Paula, D P; Claudino, D; Timbó, R V; Miranda, J E; Bemquerer, M P; Ribeiro, A C J; Sujii, E R; Fontes, E M G; Pires, C S S
Expression and activity of antioxidant enzymes during potato tuber dormancy
Summary The expression of antioxidant genes has been analyzed in a potato plant and during tuber dormancy. Manganese superoxide dismutase\\u000a (MnSOD), cytosolic copper and zinc superoide dismutase (Cu\\/ZnSOD), catalase class II, cytosolic ascorbate peroxidase (APX)\\u000a and glutathione peroxidase (GPX) are expressed at the RNA level in all the contexts analyzed. By contrast, the expression\\u000a of the iron superoxide dismutase (FeSOD) and
J. A. Rojas-Beltran; F. Dejaeghere; M. Abd Alla Kotb; P. Du Jardin
Genetic relationships between preharvest sprouting and dormancy in barley
Preharvest sprouting (PHS) and dormancy (DOR) can be problems in barley production and end use quality, especially for barley\\u000a used for seed and malting. Three crosses previously analyzed for DOR inheritance, were reanalyzed for PHS and DOR inheritance\\u000a using artificial rain to calculate sprout score (SSc) and measure alpha-amylase activity (AA). Germination percentage of untreated\\u000a grain for DOR was also
S. E. Ullrich; H. Lee; J. A. Clancy; I. A. del Blanco; V. A. Jitkov; A. Kleinhofs; F. Han; D. Prada; I. Romagosa; J. L. Molina-Cano
Seed dormancy mechanisms in warm season grass species
Available evidence suggests that there are at least two locations for dormancy mechanisms in primary dormant seeds: mechanisms\\u000a based within the embryo covering structures, and mechanisms based within the embryo. Mechanisms within the covering structures\\u000a may involve mechanical, permeability and chemical barriers to germination. Mechanisms within the embryo may involve the expression\\u000a of certain genes, levels of certain plant growth
Steve W. Adkins; Sean M. Bellairs; Don S. Loch
Seeking the Role of NO in Breaking Seed Dormancy
In the course of evolution, higher plants developed a special reproductive organ, the seed, which\\u000a ensures their spatio-temporal distribution and perpetuation of the species. The fate of the future plant\\u000a is almost completely determined when the seed "decides" to germinate. A number of dormancy\\u000a mechanisms serve to detect surrounding conditions and define the appropriate point in time for germination.\\u000a To ensure survival
Zlatko Giba; Dragoljub Grubiši?; Radomir Konjevi?
Human Granuloma In Vitro Model, for TB Dormancy and Resuscitation
Tuberculosis (TB) is responsible for death of nearly two million people in the world annually. Upon infection, Mycobacterium tuberculosis (Mtb) causes formation of granuloma where the pathogen goes into dormant state and can live for decades before resuscitation to develop active disease when the immune system of the host is weakened and/or suppressed. In an attempt to better understand host-pathogen interactions, several groups have been developing in vitro models of human tuberculosis granuloma. However, to date, an in vitro granuloma model in which Mtb goes into dormancy and can subsequently resuscitate under conditions that mimic weakening of the immune system has not been reported. We describe the development of a biomimetic in vitro model of human tuberculosis granuloma using human primary leukocytes, in which the Mtb exhibited characteristics of dormant mycobacteria as demonstrated by (1) loss of acid-fastness, (2) accumulation of lipid bodies (3) development of rifampicin-tolerance and (4) gene expression changes. Further, when these micro granulomas were treated with immunosuppressant anti-tumor necrosis factor-alpha monoclonal antibodies (anti-TNF? mAbs), resuscitation of Mtb was observed as has been found in humans. In this human in vitro granuloma model triacylglycerol synthase 1deletion mutant (?tgs1) with impaired ability to accumulate triacylglycerides (TG), but not the complemented mutant, could not go into dormancy. Deletion mutant of lipY, with compromised ability to mobilize the stored TG, but not the complemented mutant, was unable to come out of dormancy upon treatment with anti-TNF? mAbs. In conclusion, we have developed an in vitro human tuberculosis granuloma model that largely exhibits functional features of dormancy and resuscitation observed in human tuberculosis.
Kapoor, Nidhi; Pawar, Santosh; Sirakova, Tatiana D.; Deb, Chirajyoti; Warren, William L.; Kolattukudy, Pappachan E.
Hormonal Regulation of Dormancy in Developing Sorghum Seeds.
The role of abscisic acid (ABA) and gibberellic acid (GA) in determining the dormancy level of developing sorghum (Sorghum bicolor [L.] Moench.) seeds from varieties presenting contrasting preharvest sprouting behavior (Redland B2, susceptible; IS 9530, resistant) was investigated. Panicles from both varieties were sprayed soon after pollination with fluridone or paclobutrazol to inhibit ABA and GA synthesis, respectively. Fluridone application to the panicles increased germinability of Redland B2 immature caryopses, whereas early treatment with paclobutrazol completely inhibited germination of this variety during most of the developmental period. Incubating caryopses in the presence of 100 [mu]M GA4+7 overcame the inhibitory effect of paclobutrazol, but also stimulated germination of seeds from other treatments. IS 9530 caryopses presented germination indices close to zero until physiological maturity (44 d after pollination) in control and paclobutrazol-treated particles. However, fluridone-treated caryopses were released from dormancy earlier than control and paclobutrazol-treated caryopses. Incubation in the presence of GA4+7 stimulated germination of caryopses from all treatments. Our results support the proposition that a low dormancy level (which is related to a high preharvest sprouting susceptibility) is determined not only by a low embryonic sensitivity to ABA, but also by a high GA content or sensitivity.
Steinbach, H. S.; Benech-Arnold, R. L.; Sanchez, R. A.
The role of abscisic acid (ABA) and gibberellic acid (GA) in determining the dormancy level of developing sorghum (Sorghum bicolor [L.] Moench.) seeds from varieties presenting contrasting preharvest sprouting behavior (Redland B2, susceptible; IS 9530, resistant) was investigated. Panicles from both varieties were sprayed soon after pollination with fluridone or paclobutrazol to inhibit ABA and GA synthesis, respectively. Fluridone application to the panicles increased germinability of Redland B2 immature caryopses, whereas early treatment with paclobutrazol completely inhibited germination of this variety during most of the developmental period. Incubating caryopses in the presence of 100 [mu]M GA4+7 overcame the inhibitory effect of paclobutrazol, but also stimulated germination of seeds from other treatments. IS 9530 caryopses presented germination indices close to zero until physiological maturity (44 d after pollination) in control and paclobutrazol-treated particles. However, fluridone-treated caryopses were released from dormancy earlier than control and paclobutrazol-treated caryopses. Incubation in the presence of GA4+7 stimulated germination of caryopses from all treatments. Our results support the proposition that a low dormancy level (which is related to a high preharvest sprouting susceptibility) is determined not only by a low embryonic sensitivity to ABA, but also by a high GA content or sensitivity. PMID:12223597
Regulation of Tumor Cell Dormancy by Tissue Microenvironments and Autophagy
The development of metastasis is the major cause of death in cancer patients. In certain instances, this occurs shortly after primary tumor detection and treatment, indicating these lesions were already expanding at the moment of diagnosis or initiated exponential growth shortly after. However, in many types of cancer, patients succumb to metastatic disease years and sometimes decades after being treated for a primary tumor. This has led to the notion that in these patients residual disease may remain in a dormant state. Tumor cell dormancy is a poorly understood phase of cancer progression and only recently have its underlying molecular mechanisms started to be revealed. Important questions that remain to be elucidated include not only which mechanisms prevent residual disease from proliferating but also which mechanisms critically maintain the long-term survival of these disseminated residual cells. Herein, we review recent evidence in support of genetic and epigenetic mechanisms driving dormancy. We also explore how therapy may cause the onset of dormancy in the surviving fraction of cells after treatment and how autophagy may be a mechanism that maintains the residual cells that are viable for prolonged periods.
Sosa, Maria Soledad; Bragado, Paloma; Debnath, Jayanta
Imaging Spectrometer Designs Utilizing Immersed Gratings With Accessible Entrance Slit
A compact imaging spectrometer comprises an entrance slit, a catadioptric lens with a mirrored surface, a grating, and a detector array. The entrance slit directs light to the mirrored surface of the catadioptric lens; the mirrored surface reflects the light back through the lens to the grating. The grating receives the light from the catadioptric lens and diffracts the light
Michael P. Chrisp; Scott A. Lerner
12. SITE BUILDING 002 - SCANNER BUILDING - MAIN ENTRANCE LOOKING AT MAIN ENTRANCE TO TECHNICAL FACILITY, GROUND LEVEL. VIEW IS LOOKING SOUTH 20° EAST. - Cape Cod Air Station, Technical Facility-Scanner Building & Power Plant, Massachusetts Military Reservation, Sandwich, Barnstable County, MA
20. MAIN ENTRANCE STAIRWAY AREA, 1913 ADDITION, LOOKING EAST-NORTHEAST. AT LEFT IS ENTRY FROM MAIN ENTRANCE VESTIBULE, AND AT RIGHT IS LANDING BETWEEN STAIR LEVELS LEADING TO SECOND FLOOR RECEPTION AREA - Underwriters' Laboratories, 207-231 East Ohio Street, Chicago, Cook County, IL
15. Front security entrance to the perimeter acquisition radar building, ...
15. Front security entrance to the perimeter acquisition radar building, showing rotogates 1 and 2 and entrance door to security operations control center (SOCC), room #108 - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND
7. CLOSE-UP VIEW OF ENTRANCE TO BUILDING NO. 33 FACING EAST. VIEW SHOWS CONCRETE PLANTING BOXES ON EACH SIDE OF ENTRANCE AND CONCRETE CANOPY OVERHANG ABOVE. - U.S. Naval Base, Pearl Harbor, Marine Barracks, West Loch, B Avenue near Arizona Road, Pearl City, Honolulu County, HI
DETAIL OF MAIN ENTRANCE ON NORTH SIDE; NOTE GOTHIC DETAILING ON ENTRANCE PAVILION, PARAPET: ORIGINAL, PORTION OF THIS BUILDING WAS DESIGNED BY RATH PLANT ENGINEER J.S. BARTLEY IN 1925 - Rath Packing Company, Administration Building, Sycamore Street between Elm & Eighteenth Streets, Waterloo, Black Hawk County, IA
Genetic control of dormancy in a Triumph/Morex cross in barley.
Seed dormancy in barley ( Hordeum vulgare L.) is one of the most important parameters affecting malting. Seed dormancy is quantitatively inherited and variously influenced by the environment. The objectives of the present study were to determine the genome location and effects of quantitative trait loci (QTLs) involved in the expression of seed dormancy in a barley cross between two varieties derived from different germplasm pools. Using a doubled-haploid population of 107 lines of the cross between the malting types Triumph (two-row, dormant) and Morex (six-row, non-dormant), seed dormancy phenotypic data sets from five environments and a 147-marker linkage map were developed in order to perform QTL analyses with simple interval mapping and simplified composite interval mapping procedures. Two different types of variables were considered for seed dormancy characterization: (1) level of dormancy induced during seed development, which was indirectly measured as germination percentage at 3 days and 7 days, GP3 and GP7 respectively; (2) rate of dormancy release in the course of a period after seed harvest (after-ripening). Different mechanisms of genetic control were detected for these two types of dormancy-related traits. A major and consistent dormancy QTL near the centromere on chromosome 7(5H) was associated with the establishment of dormancy during seed development and accounted for 52% and 33% of the variability for GP3 and GP7, respectively. Two other QTLs located in the vicinity of the vrs1 locus on chromosome 2(2H) and near the long arm telomere on chromosome 7(5H) explained 9% and 19% of variation, respectively, for the rate of dormancy release during after-ripening. Likewise, seed dormancy was assessed in an F(2) population derived from the cross between two dormant types of distinct germplasm groups, Triumph (European, two-row, malt) and Steptoe (North American, six-row, feed), which showed similar but not identical genetic control for dormancy. Interestingly, there is remarkable dormancy QTL conservation in both regions on chromosome 7(5H) identified in this study and among other barley mapping populations. These widely conserved QTLs show potential as targets for selection of a moderate level of seed dormancy in breeding programs. PMID:14991108
Prada, D; Ullrich, S E; Molina-Cano, J L; Cistué, L; Clancy, J A; Romagosa, I
Ecotypic variation of summer dormancy relaxation associated with rainfall gradient in the geophytic grass Poa bulbosa
Background and Aims Summer dormancy is an adaptive trait in geophytes inhabiting regions with a Mediterranean climate, allowing their survival through the hot and dry summers. Summer dormancy in Poa bulbosa is induced by increasing day-length and temperature and decreasing water availability during spring. Populations from arid habitats became dormant earlier than those from mesic habitats. Relaxation of dormancy was promoted by the hot, dry summer conditions. Here we test the hypothesis that dormancy relaxation is also delayed in ecotypes of P. bulbosa inhabiting arid regions, as a cautious strategy related to the greater unpredictability of autumn rains associated with decreasing precipitation. Methods Ecotypes collected across a precipitation gradient (100–1200 mm year?1) in the Mediterranean climate region were grown under similar conditions in a net-house in Israel. Differences among ecotypes in dormancy induction and dormancy relaxation were determined by measuring time to dormancy onset in spring, and time to sprouting after the first effective rain in autumn. Seasonal and ecotype variation in dormancy relaxation were assessed by measuring time to sprouting initiation, rate of sprouting and maximal sprouting of resting dry bulbs sampled in the net-house during late spring, and mid- and late summer, and planted in a wet substrate at temperatures promoting (10 °C) or limiting (20 °C) sprouting. Key Results Earlier dormancy in the spring and delayed sprouting in autumn were correlated with decreasing mean annual rainfall at the site of ecotype origin. Seasonal and ecotype differences in dormancy relaxation were expressed in bulbs planted at 20 °C. During the summer, time to sprouting decreased while rate of sprouting and maximal sprouting increased, indicating dormancy relaxation. Ecotypes from more arid sites across the rainfall gradient showed delayed onset of sprouting and lower maximal sprouting, but did not differ in rate of sprouting. Planting at 10 °C promoted sprouting and cancelled differences among ecotypes in dormancy relaxation. Conclusions Both the induction and the relaxation of summer dormancy in P. bulbosa are correlated with mean annual precipitation at the site of population origin. Ecotypes from arid habitats have earlier dormancy induction and delayed dormancy relaxation, compared with those from mesic habitats.
Ofir, Micha; Kigel, Jaime
Regulation of Summer Dormancy by Water Deficit and ABA in Poa bulbosa Ecotypes
Background and Aims Survival of many herbaceous species in Mediterranean habitats during the dry, hot summer depends on the induction of summer dormancy by changes in environmental conditions during the transition between the winter (growth) season to the summer (resting) season, i.e. longer days, increasing temperature and drought. In Poa bulbosa, a perennial geophytic grass, summer dormancy is induced by long days, and the induction is enhanced by high temperature. Here the induction of summer dormancy in a Mediterranean perennial grass by water deficit under non-inductive photoperiodic conditions is reported for the first time. Methods Plants grown under 22/16 °C and non-inductive short-day (9 h, SD) were subjected to water deficit (WD), applied as cycles of reduced irrigation, or sprayed with ABA solutions. They were compared with plants in which dormancy was induced by transfer from SD to inductive long-day (16 h, LD). Responses of two contrasting ecotypes, from arid and mesic habitats were compared. Dormancy relaxation in bulbs from these ecotypes and treatments was studied by comparing sprouting capacity in a wet substrate at 10 °C of freshly harvested bulbs to that of dry-stored bulbs at 40 °C. Endogenous ABA in the bulbs was determined by monoclonal immunoassay analysis. Key Results Dormancy was induced by WD and by ABA application in plants growing under non-inductive SD. Dormancy induction by WD was associated with increased levels of ABA. Bulbs were initially deeply dormant and their sprouting capacity was very low, as in plants in which dormancy was induced by LD. Dormancy was released after 2 months dry storage at 40 °C in all treatments. ABA levels were not affected by dormancy relaxation. Conclusions Summer dormancy in P. bulbosa can be induced by two alternative and probably additive pathways: (1) photoperiodic induction by long-days, and (2) water deficit. Increased levels of endogenous ABA are involved in both pathways.
Sympatric species of Hibbertia (Dilleniaceae) vary in dormancy break and germination requirements: implications for classifying morphophysiological dormancy in Mediterranean biomes
Background and Aims Several ecologically important plant families in Mediterranean biomes have seeds with morphophysiological dormancy (MPD) but have been poorly studied. The aim of this study was to understand the seed ecology of these species by focusing on the prominent, yet intractably dormant Australian genus Hibbertia. It was hypothesized that the slow germination in species of this genus is caused by a requirement for embryo growth inside the seed before germination, and that initiation of embryo growth is reliant upon a complex sequence of environmental cues including seasonal fluctuations in temperature and moisture, and an interplay with light and smoke. Using the results, the classification of the MPD level in species of Hibbertia is considered. Methods Four species of Hibbertia in winter rainfall south-western Australia were selected. These species, whilst differing in geographic distributions, are variously sympatric, and all are important understorey components of plant communities. The following aspects related to dormancy break, embryo growth and germination were investigated: temperature and moisture requirements; effects of karrikinolide, gibberellic acid and aerosol smoke; and phenology. Key Results Following exposure to wet/dry cycles at low or high temperatures, embryo growth and germination occurred, albeit slowly in all species at low temperatures when moisture was unlimited, corresponding to winter in south-west Australia. Photo regime influenced germination only in H. racemosa. Aerosol smoke triggered substantial germination during the 1st germination season in H. huegelii and H. hypericoides. Conclusions Although the study species are con-generic, sympatric and produce seeds of identical morphology, they possessed different dormancy-break and germination requirements. The physiological component of MPD was non-deep in H. racemosa but varied in the other three species where more deeply dormant seeds required >1 summer to overcome dormancy and, thus, germination was spread over time. Embryos grew during winter, but future studies need to resolve the role of cold versus warm stratification by using constant temperature regimes. To include Mediterranean species with MPD, some modifications to the current seed-dormancy classification system may need consideration: (a) wet/dry conditions for warm stratification and (b) a relatively long period for warm stratification. These outcomes have important implications for improving experimental approaches to resolve the effective use of broadcast seed for ecological restoration.
Hidayati, Siti N.; Walck, Jeffrey L.; Merritt, David J.; Turner, Shane R.; Turner, David W.; Dixon, Kingsley W.
Molecular dissection of a dormancy QTL region near the chromosome 7 (5H) L telomere in barley
Moderate seed dormancy is desirable in barley ( Hordeum vulgare L.). It is difficult for breeders to manipulate seed dormancy in practical breeding programs because of complex inheritance and large environmental effects. Quantitative trait locus (QTL) mapping opens a way for breeders to manipulate quantitative trait genes. A seed dormancy QTL, SD2, was mapped previously in an 8-cM interval near
W. Gao; J. A. Clancy; F. Han; D. Prada; A. Kleinhofs; S. E. Ullrich
Grain dormancy and light quality effects on germination in the model grass Brachypodium distachyon.
• Lack of grain dormancy in cereal crops such as barley and wheat is a common problem affecting farming areas around the world, causing losses in yield and quality because of preharvest sprouting. Control of seed or grain dormancy has been investigated extensively using various approaches in different species, including Arabidopsis and cereals. However, the use of a monocot model plant such as Brachypodium distachyon presents opportunities for the discovery of new genes related to grain dormancy that are not present in modern commercial crops. • In this work we present an anatomical description of the Brachypodium caryopsis, and we describe the dormancy behaviour of six common diploid Brachypodium inbred genotypes. We also study the effect of light quality (blue, red and far-red) on germination, and analyse changes in abscisic acid levels and gene expression between a dormant and a non-dormant Brachypodium genotype. • Our results indicate that different genotypes display high natural variability in grain dormancy and that the characteristics of dormancy and germination are similar to those found in other cereals. • We propose that Brachypodium is an ideal model for studies of grain dormancy in grasses and can be used to identify new strategies for increasing grain dormancy in crop species. PMID:22039925
Barrero, José M; Jacobsen, John V; Talbot, Mark J; White, Rosemary G; Swain, Stephen M; Garvin, David F; Gubler, Frank
Germination of Astragalus hamosus and Medicago orbicularis as affected by seed-coat dormancy breaking techniques
Milkvetch (Astragalus hamosus) and button medic (Medicago orbicularis) are two annual forage legumes very interesting for agricultural purposes in Mediterranean pastures. As other legumes, they exhibit dormancy, which delays and reduces germination. The germination response of these species to mechanical, physical and chemical scarification, applied for overcoming dormancy, has been studied. The almost full and rapid germination achieved by hand
C. Patanč; F. Gresta
Some reflections on the relationship between endogenous hormones and light-mediated seed dormancy
The relationships between phytochrome and endogenous hormones in the light-mediated control of seed dormancy are discussed. It is concluded that gibberellins are primarily involved in post-dormancy metabolic processes leading to embryo growth and radicle emergence, such as food reserve mobilisation and endosperm softening. Evidence is considered that germination inhibitors, particularly abscisic acid, are involved in the establishment and maintenance of
Tudor H. Thomas
Dormancy of Arabidopsis seeds and barley grains can be broken by nitric oxide
Seeds of Arabidopsis thaliana (L.) Heynh. and grains of barley ( Hordeum vulgare L.) were used to characterize the affects of nitric oxide (NO) on seed dormancy. Seeds of the C24 and Col-1 ecotypes of Arabidopsis are almost completely dormant when freshly harvested, but dormancy was broken by stratification for 3 days at 4°C or by imbibition of seeds with the
Paul C. Bethke; Frank Gubler; John V. Jacobsen; Russell L. Jones
On the role of abscisic acid in seed dormancy of red rice
Abscisic acid (ABA) is commonly assumed to be the primary effector of seed dormancy, but conclusive evidence for this role is lacking. This paper reports on the relationships occurring in red rice between ABA and seed dormancy. Content of free ABA in dry and imbibed caryopses, both dormant and after-ripened, the effects of inhibitors, and the ability of applied ABA
Alberto Gianinetti; Paolo Vernieri
Release of sunflower seed dormancy by cyanide: cross-talk with ethylene signalling pathway
Freshly harvested sunflower (Helianthus annuus L.) seeds are considered to be dormant because they fail to germinate at relatively low temperatures (10 ? C). This dormancy results mainly from an embryo dor- mancy and disappears during dry storage. Although endogenous ethylene is known to be involved in sunflower seed alleviation of dormancy, little attention had been paid to the possible
Krystyna Oracz; Hayat El-Maarouf-Bouteau; Renata Bogatek; F. Corbineau; C. Bailly
ABA inhibits germination but not dormancy release in mature imbibed seeds of Lolium rigidum Gaud
Dormancy release in imbibed annual ryegrass (Lolium rigidum Gaud.) seeds is promoted in the dark but inhibited in the light. The role of abscisic acid (ABA) in inhibition of dormancy release was found to be negligible, compared with its subsequent effect on germination of dormant and non-dormant seeds. Inhibitors of ABA metabolism had the expected effects on seed germination but
Danica E. Goggin; Kathryn J. Steadman; R. J. Neil Emery; Scott C. Farrow; Roberto L. Benech-Arnold; Stephen B. Powles
The promotive effect of combustion products from plant vegetation on the release of seeds from dormancy
In darkness, dormancy was imposed on seeds of lettuce (Lactuca sativa L. cv. Grand rapids) by high temperature and on seeds of oilseed rape (Brassica napus L. cv. Apex) by osmotic stress using polyethylene glycol (PEG 8000). In both cases, dormancy was broken by incubating the seeds in aqueous extracts of combustion products from Salix viminalis wood chips or Themeda
M. A. Thornton; T. H. Thomas; N. C. B. Peters
Effect of Gibberellic Acid, Kinetin and Other Substances on Seed Dormancy
THE seeds of many plants, especially woody species from temperate regions, are dormant when harvested and require a period of chilling (`stratification') before they become capable of germination. As part of an investigation into the physiological basis of seed dormancy, attempts were made to replace the chilling requirement by treatment with gibberellic acid and other substances known to break dormancy.
B. Frankland
Prolonged pupal dormancy is associated with significant fitness cost for adults of Rhagoletis cerasi (Diptera: Tephritidae).
In temperate areas, dormancy (diapause and/or quiescence) enables herbivorous insect species to persist and thrive by synchronizing growth and reproduction with the seasonal phenology of their host plants. Within-population variability in dormancy increases survival chances under unpredictable environmental changes. However, prolonged dormancy may be costly, incurring trade-offs in important adult fitness traits such as life span and reproduction. We used the European cherry fruit fly, Rhagoletis cerasi, a stenophagous, univoltine species that overwinters in the pupal stage for usually one or more years to test the hypotheses that prolonged dormancy of pupae has trade-offs with body size, survival and reproduction of the resulting adults. We used two geographically isolated populations of R. cerasi to compare the demographic traits of adults obtained from pupae subjected to one or two cycles of warm-cold periods (annual and prolonged dormancy respectively). Regardless of population, adults from pupae that experienced prolonged dormancy were larger than counterparts emerging within 1year. Prolonged dormancy did not affect adult longevity but both lifetime fecundity and oviposition were significantly decreased. Extension of the life cycle of some individuals in R. cerasi populations in association with prolonged dormancy is likely a bet-hedging strategy. PMID:22684113
Moraiti, Cleopatra A; Nakas, Christos T; Papadopoulos, Nikos T
A transgenic approach to controlling wheat seed dormancy level by using Triticeae DOG1-like genes.
Seed dormancy is an important agronomic trait: low levels can cause premature germination, while too much can inhibit uniform germination. As an approach to controlling the seed dormancy level in crops, we used Triticeae DOG1-like genes as transgenes. DOG1 is an Arabidopsis gene that underlies natural variation in seed dormancy. We previously showed that although their sequence similarities to DOG1 were low, some cereal DOG1-like genes enhanced seed dormancy in Arabidopsis. Here, we introduced two DOG1-like genes, TaDOG1L4 from wheat and HvDOG1L1 from barley, individually into the wheat cultivar Fielder. Their overexpression under the control of a maize ubiquitin promoter enhanced the seed dormancy level while leaving other traits unchanged. TaDOG1L4 was more effective than HvDOG1L1, which accords with the previously revealed difference in the effectiveness of these two genes in Arabidopsis seed dormancy. Knockdown of endogenous TaDOG1L4 in Fielder using double-strand RNA interference decreased the seed dormancy level by several tens of percent. This result indicates that some degree of seed dormancy inherent in wheat is imparted by DOG1-like genes. PMID:24752830
Ashikawa, Ikuo; Mori, Masahiko; Nakamura, Shingo; Abe, Fumitaka
Phoenix clones: recovery after long-term defoliation-induced dormancy
Many long-lived plants are known to prolong dormancy in response to abiotic stresses such as drought. We are unaware, however, of any reports of plants prolonging dormancy in response to biotic stresses such as herbivory. We monitored 140 putative Solidago missouriensis clones (hereafter clones) ‡ 13 years before, during and after intense defoliation by the specialist herbivore Trirhabda canadensis. Eight
Patrice A. Morrow; Joel P. Olfelt
The relativistic titls of Giza pyramids' entrance-passages
The tilts of Giza pyramids' entrance-passages have never been considered as if they were the result of relativistic mathematical equations, and never been thought to encode the Earth's obliquity parameters. This paper presents an attempt to retrieve the method of establishing the equations that the pyramids' designer used to quantify the entrance-passages' tilts of these architectonic masterpieces. It proves that the pyramids' designer was able to include the geographic, astronomical and time parameters in one relativistic equation, encoding the date of the design of the Giza pyramids in the tilt of the entrance passage of the great pyramid.
Aboulfotouh, H.
Forecasting emergence and movement of overwintering hazelnut big bud mites from big buds
Eriophyoid big bud mites are key pests of hazelnut throughout the world, but they are difficult to control with chemicals\\u000a or other methods because they are protected inside the bud. The most effective time for control is during the relatively short\\u000a emergence period which is difficult for growers to predict. The key objectives of this study were to monitor mite
Janette Webber; R. Bruce Chapman; S. P. Worner
Identification of the Arabidopsis REDUCED DORMANCY 2 Gene Uncovers a Role for the Polymerase Associated Factor 1 Complex in Seed Dormancy
The life of a plant is characterized by major phase transitions. This includes the agriculturally important transitions from seed to seedling (germination) and from vegetative to generative growth (flowering induction). In many plant species, including Arabidopsis thaliana, freshly harvested seeds are dormant and incapable of germinating. Germination can occur after the release of dormancy and the occurrence of favourable environmental conditions. Although the hormonal control of seed dormancy is well studied, the molecular mechanisms underlying the induction and release of dormancy are not yet understood. In this study, we report the cloning and characterization of the mutant reduced dormancy 2-1 (rdo2-1). We found that RDO2 is allelic to the recently identified dormancy gene TFIIS, which is a transcription elongation factor. HUB1, which was previously called RDO4, was identified in the same mutagenesis screen for reduced dormancy as rdo2-1 and was also shown to be involved in transcription elongation. The human homologues of RDO2 and HUB1 interact with the RNA Polymerase II Associated Factor 1 Complex (PAF1C). Therefore, we investigated the effect of other Arabidopsis PAF1C related factors; VIP4, VIP5, ELF7, ELF8 and ATXR7 on seed dormancy. Mutations in these genes resulted in reduced dormancy, similar to hub1-2 and rdo2-1. Consistent with a role at the end of seed maturation, we found that HUB1, RDO2 and VIP5 are upregulated during this developmental phase. Since mutants in PAF1C related factors are also described to be early flowering, we conclude that these components are involved in the regulation of both major developmental transitions in the plant.
Carles, Annaick; Li, Yong; Horold, Anja; van Nocker, Steven; Soppe, Wim J. J.
Environmental regulation of dormancy loss in seeds of Lomatium dissectum (Apiaceae)
Background and Aims Lomatium dissectum (Apiaceae) is a perennial, herbaceous plant of wide distribution in Western North America. At the time of dispersal, L. dissectum seeds are dormant and have under-developed embryos. The aims of this work were to determine the requirements for dormancy break and germination, to characterize the type of seed dormancy, and to determine the effect of dehydration after embryo growth on seed viability and secondary dormancy. Methods The temperature requirements for embryo growth and germination were investigated under growth chamber and field conditions. The effect of GA3 on embryo growth was also analysed to determine the specific type of seed dormancy. The effect of dehydration on seed viability and induction of secondary dormancy were tested in seeds where embryos had elongated about 4-fold their initial length. Most experiments examining the nature of seed dormancy were conducted with seeds collected at one site in two different years. To characterize the degree of variation in dormancy-breaking requirements among seed populations, the stratification requirements of seeds collected at eight different sites were compared. Key Results Embryo growth prior to and during germination occurred at temperatures between 3 and 6 °C and was negligible at stratification temperatures of 0·5 and 9·1 °C. Seeds buried in the field and exposed to natural winter conditions showed similar trends. Interruption of the cold stratification period by 8 weeks of dehydration decreased seed viability by about 30 % and induced secondary dormancy in the remaining viable seeds. Comparison of the cold stratification requirements of different seed populations indicates that seeds collected from moist habitats have longer cold stratification requirements that those from semiarid environments. Conclusions Seeds of L. dissectum have deep complex morphophysiological dormancy. The requirements for dormancy break and germination reflect an adaptation to trigger germination in late winter.
Scholten, Melissa; Donahue, Jacklyn; Shaw, Nancy L.; Serpe, Marcelo D.
Differential control of seed primary dormancy in Arabidopsis ecotypes by the transcription factor SPATULA.
Freshly matured seeds exhibit primary dormancy, which prevents germination until environmental conditions are favorable. The establishment of dormancy occurs during seed development and involves both genetic and environmental factors that impact on the ratio of two antagonistic phytohormones: abscisic acid (ABA), which promotes dormancy, and gibberellic acid, which promotes germination. Although our understanding of dormancy breakage in mature seeds is well advanced, relatively little is known about the mechanisms involved in establishing dormancy during seed maturation. We previously showed that the SPATULA (SPT) transcription factor plays a key role in regulating seed germination. Here we investigate its role during seed development and find that, surprisingly, it has opposite roles in setting dormancy in Landsberg erecta and Columbia Arabidopsis ecotypes. We also find that SPT regulates expression of five transcription factor encoding genes: ABA-INSENSITIVE4 (ABI4) and ABI5, which mediate ABA signaling; REPRESSOR-OF-GA (RGA) and RGA-LIKE3 involved in gibberellic acid signaling; and MOTHER-OF-FT-AND-TFL1 (MFT) that we show here promotes Arabidopsis seed dormancy. Although ABI4, RGA, and MFT are repressed by SPT, ABI5 and RGL3 are induced. Furthermore, we show that RGA, MFT, and ABI5 are direct targets of SPT in vivo. We present a model in which SPT drives two antagonistic "dormancy-repressing" and "dormancy-promoting" routes that operate simultaneously in freshly matured seeds. Each of these routes has different impacts and this in turn explains the opposite effect of SPT on seed dormancy of the two ecotypes analyzed here. PMID:23754415
Vaistij, Fabián E; Gan, Yinbo; Penfield, Steven; Gilday, Alison D; Dave, Anuja; He, Zhesi; Josse, Eve-Marie; Choi, Giltsu; Halliday, Karen J; Graham, Ian A
Differential control of seed primary dormancy in Arabidopsis ecotypes by the transcription factor SPATULA
Freshly matured seeds exhibit primary dormancy, which prevents germination until environmental conditions are favorable. The establishment of dormancy occurs during seed development and involves both genetic and environmental factors that impact on the ratio of two antagonistic phytohormones: abscisic acid (ABA), which promotes dormancy, and gibberellic acid, which promotes germination. Although our understanding of dormancy breakage in mature seeds is well advanced, relatively little is known about the mechanisms involved in establishing dormancy during seed maturation. We previously showed that the SPATULA (SPT) transcription factor plays a key role in regulating seed germination. Here we investigate its role during seed development and find that, surprisingly, it has opposite roles in setting dormancy in Landsberg erecta and Columbia Arabidopsis ecotypes. We also find that SPT regulates expression of five transcription factor encoding genes: ABA-INSENSITIVE4 (ABI4) and ABI5, which mediate ABA signaling; REPRESSOR-OF-GA (RGA) and RGA-LIKE3 involved in gibberellic acid signaling; and MOTHER-OF-FT-AND-TFL1 (MFT) that we show here promotes Arabidopsis seed dormancy. Although ABI4, RGA, and MFT are repressed by SPT, ABI5 and RGL3 are induced. Furthermore, we show that RGA, MFT, and ABI5 are direct targets of SPT in vivo. We present a model in which SPT drives two antagonistic "dormancy-repressing" and "dormancy-promoting" routes that operate simultaneously in freshly matured seeds. Each of these routes has different impacts and this in turn explains the opposite effect of SPT on seed dormancy of the two ecotypes analyzed here.
Vaistij, Fabian E.; Gan, Yinbo; Penfield, Steven; Gilday, Alison D.; Dave, Anuja; He, Zhesi; Josse, Eve-Marie; Choi, Giltsu; Halliday, Karen J.; Graham, Ian A.
Tanned or Burned: The Role of Fire in Shaping Physical Seed Dormancy
Plant species with physical seed dormancy are common in mediterranean fire-prone ecosystems. Because fire breaks seed dormancy and enhances the recruitment of many species, this trait might be considered adaptive in fire-prone environments. However, to what extent the temperature thresholds that break physical seed dormancy have been shaped by fire (i.e., for post-fire recruitment) or by summer temperatures in the bare soil (i.e., for recruitment in fire-independent gaps) remains unknown. Our hypothesis is that the temperature thresholds that break physical seed dormancy have been shaped by fire and thus we predict higher dormancy lost in response to fire than in response to summer temperatures. We tested this hypothesis in six woody species with physical seed dormancy occurring in fire-prone areas across the Mediterranean Basin. Seeds from different populations of each species were subject to heat treatments simulating fire (i.e., a single high temperature peak of 100°C, 120°C or 150°C for 5 minutes) and heat treatments simulating summer (i.e., temperature fluctuations; 30 daily cycles of 3 hours at 31°C, 4 hours at 43°C, 3 hours at 33°C and 14 hours at 18°C). Fire treatments broke dormancy and stimulated germination in all populations of all species. In contrast, summer treatments had no effect over the seed dormancy for most species and only enhanced the germination in Ulex parviflorus, although less than the fire treatments. Our results suggest that in Mediterranean species with physical dormancy, the temperature thresholds necessary to trigger seed germination are better explained as a response to fire than as a response to summer temperatures. The high level of dormancy release by the heat produced by fire might enforce most recruitment to be capitalized into a single post-fire pulse when the most favorable conditions occur. This supports the important role of fire in shaping seed traits.
Moreira, Bruno; Pausas, Juli G.
Short Photoperiod Induces Dormancy in Lotus (Nelumbo nucifera)
• Background and Aims Lotus (Nelumbo nucifera) has been cultivated as an ornamental and food plant in Japan for more than 1000 years. As large areas are required for its cultivation (approximately 2?m2 per plant), physiological research, such as into the effect of environmental factors on dormancy, has not been well studied until recently. In this paper, seedlings were used to examine environmental factors affecting dormancy induction. • Methods In a first experiment, seeds were sown from 6 April to 6 October at 2-month intervals, and cultivated for 2 months in an unheated greenhouse. In a second experiment, seeds were prepared for germination on 16 November and 16 May and the seedlings were grown at 25 or 30?°C under natural daylength in phytotron growth rooms. After 1 month, the seedlings were cultivated at 20, 25 or 30?°C for a further month. The number of leaves and rhizome branches on the main stem were counted, and growth of rhizomes on the main stem was calculated using a rhizome enlargement index (= maximum internode diameter/internode length) after 2 months of culture in both experiments. • Key Results Rhizomes elongated without enlargement when the seeds were sown in April and June. Sowing the seeds in August and October resulted in rhizome enlargement from the tenth and fifth internodes, respectively. Rhizomes enlarged in the November-sowing but elongated in the May-sowing irrespective of temperature treatments under natural daylength in the phytotron rooms. The seedlings cultivated from May at 25–30?°C for 2 months had more leaves, and more rhizome branches and nodes than those cultivated from November. • Conclusions Short days led to induced dormancy in lotus.
1. GENERAL VIEW OF ENTRANCE INTO ALUMINUM CITY TERRACE ALONG EAST HILL DRIVE. BUILDING 1 ON RIGHT, BUILDING 2 ON LEFT, FACING EAST. - Aluminum City Terrace, East Hill Drive, New Kensington, Westmoreland County, PA
55. VIEW OF WEST ENTRANCE BRIDGE CROSSING THE ARIZONA CANAL AT THE ARIZONA BILTMORE, LOOKING EAST Photographer: Kevin Kriesel-Coons, May 1990 - Arizona Canal, North of Salt River, Phoenix, Maricopa County, AZ
8. DETAIL OF EAST FRONT OF FACTORY, SHOWING MAIN ENTRANCE. VIEW TO SOUTHWEST. - Commercial & Industrial Buildings, James Beach & Sons Company Factory & Warehouse, 57 South Locust Street, Dubuque, Dubuque County, IA
12. CLOSE-UP DETAIL VIEW OF ENTRANCE DOORS TO CELL BLOCK SHOWING KEY-WINDING MECHANISM TO ROTATE THE CELL BLOCK - Montgomery County Jail, Washington & Spring Streets, Crawfordsville, Montgomery County, IN
14. Main entrance to Gwing from Apollo Drive, looking north ...
14. Main entrance to G-wing from Apollo Drive, looking north - Offutt Air Force Base, Strategic Air Command Headquarters & Command Center, Headquarters Building, 901 SAC Boulevard, Bellevue, Sarpy County, NE
3. FIRST FLOOR, FRONT ROOM WITH ENTRANCE DOORS ON THE EAST WALL - Penn School Historic District, Butler Building, SC Route 37, 1 mile South of Frogmore, St. Helena Island, Frogmore, Beaufort County, SC
8. Historic American Buildings Survey Stanley Schwartz, Photographer 1971 ENTRANCE ...
8. Historic American Buildings Survey Stanley Schwartz, Photographer 1971 ENTRANCE HALLWAY AND MAIN STAIRCASE OF HOUSE, LOOKING FROM WEST TO EAST - Governor John Hubbard House, 52 Winthrop Street, Hallowell, Kennebec County, ME
VIEW ON FIRST FLOOR AT SOUTHEAST ENTRANCE, SHOWING MAIN STAIR, DOUBLE LOADED CORRIDOR AT CENTER, AND STAIRS LEADING TO SECOND FLOOR, FACING NORTH - Schwartz Bath House, 2201-2207 East First Street, Los Angeles, Los Angeles County, CA
IET distant contextual view of entrance to shielded roadway. facing ...
IET distant contextual view of entrance to shielded roadway. facing west. stack and other buildings have been removed. INEEL negative no. HD-21-7-2 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID
EXTERIOR VIEW, LOOKING EAST, FRONT FACADE AND ENTRANCE TO COMPANY SCHOOL FOR CHILDREN OF BLACK TCI-US STEEL RED ORE MINE WORKERS - Company School for Blacks, 413 Morgan Road, Bessemer, Jefferson County, AL
Lock 1 View northwest of lock entrance. Notch for ...
Lock 1 - View northwest of lock entrance. Notch for flash boards can be seen near center, gate pocket at left. - Savannah & Ogeechee Barge Canal, Between Ogeechee & Savannah Rivers, Savannah, Chatham County, GA
2. HISTORIC AMERICAN BUILDINGS SURVEY. S. Lucas, Photographer, 1934 ENTRANCE ...
2. HISTORIC AMERICAN BUILDINGS SURVEY. S. Lucas, Photographer, 1934 ENTRANCE DETAIL, SS. PETER & PAUL'S JESUIT CHURCH, DETROIT MICHIGAN - Sts. Peter & Paul's Jesuit Church, East Jefferson Avenue & Saint Antoine Street, Detroit, Wayne County, MI
TENANT HOUSE INTERIOR, DOOR DETAIL, FRONT ENTRANCE INTO LIVING ROOM, LOOKING NORTH - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA
5. BUILDING 0503, INTERIOR WOODEN ARCHES. Looking south from entrance. ...
5. BUILDING 0503, INTERIOR WOODEN ARCHES. Looking south from entrance. - Edwards Air Force Base, South Base Sled Track, Earth Covered Bunker Types, North of Sled Track, Lancaster, Los Angeles County, CA
1. VIEW WEST SOUTHWEST OF BUILDING 7 SHOWING MAIN ENTRANCE TO OFFICES; MANAGEMENT AND FINANCE OFFICES WERE LOCATED HERE; BUILDING 23 IS AT RIGHT OF PHOTOGRAPH - Bryant Electric Company, 1421 State Street, Bridgeport, Fairfield County, CT
5. VIEW SOUTH FROM TERRACE LEVEL SHOWING ENTRANCE TO NURSES HOME NO. 1 (RIGHT) IN LINK TO NURSES HOME NO. 3 (LEFT) - Jersey City Hospital, Nurses Homes, 112-114 Clifton Place, Jersey City, Hudson County, NJ
DETAIL OF MAIN ENTRANCE ON EAST (FRONT) ELEVATION OF BUILDING. view TO SOUTHWEST. - Plattsburgh Air Force Base, Target Intelligence Training Building-Combat Center, Off Connecticut Road, east of Idaho Avenue, Plattsburgh, Clinton County, NY
9. MAGAZINE P INTERIOR, LOOKING TO DOORWAY ENTRANCE. - NIKE Missile Base C-84, Underground Storage Magazines & Launcher-Loader Assemblies, Easternmost portion of launch area, Barrington, Cook County, IL
2. MAGAZINE P, WITH ENTRANCE DOOR IN FOREGROUND, LOOKING NORTHEAST. - NIKE Missile Base C-84, Underground Storage Magazines & Launcher-Loader Assemblies, Easternmost portion of launch area, Barrington, Cook County, IL
DETAIL OF MAIN ENTRANCE ON EAST (FRONT) ELEVATION OF BUILDING. view TO WEST - Plattsburgh Air Force Base, Airmen Dining Hall, Connecticut Road, between Illinois Drive & Idaho Avenue, Plattsburgh, Clinton County, NY
17. DETAILED VIEW OF THE ENTRANCE OF THE COTTON WOOD PRESSURE PIPE Photographer: Walter J. Lubken, March 9, 1906 - Roosevelt Power Canal & Diversion Dam, Parallels Salt River, Roosevelt, Gila County, AZ
5. Lighthouse, first floor and stairs, looking south from entrance ...
5. Lighthouse, first floor and stairs, looking south from entrance - Squirrel Point Light Station, Off Highway 127, Steen Road to end of Bald Head Road, .8 mile down footpath, Arrowsic, Sagadahoc County, ME
7. Light tower, interior from entrance, looking northwest Pumpkin ...
7. Light tower, interior from entrance, looking northwest - Pumpkin Island Light Station, Pumpkin Island, at northern end of Eggemoggin Beach, off northwest end of Little Deer Island, Eggemoggin, Hancock County, ME
7. View of south court and driveway toward main entrance; ...
7. View of south court and driveway toward main entrance; and parts of north and south wings of main building; facing east. - Mission Motel, South Court, 9235 MacArthur Boulevard, Oakland, Alameda County, CA
3. View of entrance to cellar and heavy timber framing ...
3. View of entrance to cellar and heavy timber framing of the wine press building, looking southeast. - Merkel Farmstead, Wine Press Building, 8570 Louella Lane, south side of U.S. Route 64, Shiloh, St. Clair County, IL
1. GENERAL VIEW OF ENTRANCE TO BLUE RIDGE TUNNEL (LEFT) FROM SOUTHEAST. ORIGINAL BLUE RIDGE R.R. (CROZET) TUNNEL IS VISIBLE AT RIGHT. - Chesapeake & Ohio Railroad, Blue Ridge Tunnel, Highway 250 at Rockfish Gap, Afton, Nelson County, VA
53. INTERIOR, FIRST FLOOR, SOUTH ENTRANCE, SOUTH LOBBY, DETAIL OF DOOR PULLS FOR AUDITORIUM (CONFERENCE HALL) DOOR - U.S. Department of the Interior, Eighteenth & C Streets Northwest, Washington, District of Columbia, DC
54. INTERIOR, FIRST FLOOR, SOUTH ENTRANCE, SOUTH LOBBY, DETAIL OF PUSH PLATES FOR AUDITORIUM (CONFERENCE HALL) DOOR - U.S. Department of the Interior, Eighteenth & C Streets Northwest, Washington, District of Columbia, DC
52. INTERIOR, FIRST FLOOR, SOUTH ENTRANCE, SOUTH LOBBY, AUDITORIUM (CONFERENCE HALL) DOOR (4' x 5' negative; 8' x 10' print) - U.S. Department of the Interior, Eighteenth & C Streets Northwest, Washington, District of Columbia, DC
1. BUILDING 324, SOUTH SIDE, FROM F STREET OPPOSITE ENTRANCE, LOOKING NORTH. - Oakland Naval Supply Center, Commanding Officers Residences, Between E & F Streets, West of Fourth Street, Oakland, Alameda County, CA
14. Detail of possible entrance on north side of Pentagon ...
14. Detail of possible entrance on north side of Pentagon 2 (note leaning logs at center). View to west. - Pentagon Site, Pentagon 2, West of Barry's Landing off Highway 37, Fort Smith, Big Horn County, MT
3. Perspective view of west entrance to Gas House. ...
3. Perspective view of west entrance to Gas House. - Delaware, Lackawanna & Western Railroad, Scranton Yards, Gas House, 100 block of South Washington Avenue, west side, Scranton, Lackawanna County, PA
2. View of Ford Mansion looking at the front entrance ...
2. View of Ford Mansion looking at the front entrance with the fountain in the foreground - Richmond Hill Plantation, Ford Mansion, East of Richmond Hill on Ford Neck Road, Richmond Hill, Bryan County, GA
1. NORTHWEST CORNER ENTRANCE OF BUILDING, WITH VIADUCT PIER FOR JULIEN DUBUQUE BRIDGE IN FOREGROUND. VIEW TO EAST. - Commercial & Industrial Buildings, International Harvester Company Showroom, Office & Warehouse, 10 South Main Street, Dubuque, Dubuque County, IA
25. VIEW SHOWING ENTRANCE TO SILO 'ALFA,' LOOKING WEST Everett ...
25. VIEW SHOWING ENTRANCE TO SILO 'ALFA,' LOOKING WEST Everett Weinreb, photographer, March 1988 - Mount Gleason Nike Missile Site, Angeles National Forest, South of Soledad Canyon, Sylmar, Los Angeles County, CA
2. VIEW OF BARRACKS AREA, SHOWING ENTRANCE GATE AT IMMEDIATE LEFT, LOOKING WEST Everett Weinreb, photographer, March 1988 - Mount Gleason Nike Missile Site, Angeles National Forest, South of Soledad Canyon, Sylmar, Los Angeles County, CA
26. VIEW SHOWING ENTRANCE TO SILO 'ALFA,' LOOKING NORTH Marilyn ...
26. VIEW SHOWING ENTRANCE TO SILO 'ALFA,' LOOKING NORTH Marilyn Ziemer and Everett Weinreb, photographers, March 1988 - Mount Gleason Nike Missile Site, Angeles National Forest, South of Soledad Canyon, Sylmar, Los Angeles County, CA
View of south entrance to #157 through south breezeway arches ...
View of south entrance to #157 through south breezeway arches - National Home for Disabled Volunteer Soldiers, Pacific Branch, Mental Health Buildings, 11301 Wilshire Boulevard, West Los Angeles, Los Angeles County, CA
DETAIL OF LAMP ABOVE SOUTH SIDE ENTRANCE; CAMERA FACING EAST - Mare Island Naval Shipyard, Bachelor Enlisted Quarters & Offices, Walnut Avenue, east side between D Street & C Street, Vallejo, Solano County, CA
Detail of window and lamp at entrance on north side ...
Detail of window and lamp at entrance on north side of north wing; camera facing south. - Mare Island Naval Shipyard, Administrative Offices, Walnut Avenue, east side between Seventh & Eighth Streets, Vallejo, Solano County, CA
47. INTERIOR, FIRST FLOOR, ENTRANCE HALL, DETAIL OF NEWEL POST WITH LAMPS FROM THE NORTH - Mark Twain House, 351 Farmington Avenue (corrected from original address of 531 Farmington Avenue), Hartford, Hartford County, CT
42. VIEW OF WALL AT EAST ENTRANCE TO WALKWAY. 'FRANK AUZA, FLAGSTAFF SHEEP CO.' SCRATCHED INTO FRESH MORTAR CAP ON STONE WALL. February 1987 - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ
8. Detail, west corner, showing entrance fenestration, carved rafters supporting ...
8. Detail, west corner, showing entrance fenestration, carved rafters supporting metal-tiled pent roofs, tinted mortar; view to east. - Larco Building, 214 State Street, Santa Barbara, Santa Barbara County, CA
12. Cades Cove Road, view toward entrance with ruts in ...
12. Cades Cove Road, view toward entrance with ruts in road. - Great Smoky Mountains National Park Roads & Bridges, Cades Cove Road & Laurel Creek Road, From Townsend Wye to Cades Cove, Gatlinburg, Sevier County, TN
5. DETAIL OF ENTRANCE OF 14 LOGAN CIRCLE WITH SIDE BAY OF 1500 THIRTEENTH STREET NW ON RIGHT. - Logan Circle, Vermont Avenue, Rhode Island Avenue, & Thirteenth Street, Washington, District of Columbia, DC
9. VIEW OF SERVICE ENTRANCE TO NORTH BEND RANGER STATION LOOKING APPROXIMATELY EAST. BUILDING NO. 2230 IS IN THE CENTER FOREGROUND. - North Bend Ranger Station, Building 2230, 42404 Southeast North Bend Way, North Bend, King County, WA
4. SOUTH CORNER, MAIN ENTRANCE WAREHOUSE DOORS ON MAIN (SOUTHWEST) ELEVATION, AND LOADING DOCK ON SOUTHEAST ELEVATION. - North Bend Ranger Station, Building 2230, 42404 Southeast North Bend Way, North Bend, King County, WA
8. WEST REAR, DETAIL SHOWING SECOND FLOOR ENTRANCE AND WINDOW TREATMENT. See CA-174-B-22 FOR INTERIOR OF SECOND FLOOR LAB AT CENTER. - Hughes Aircraft Company, Engineering-Administration Building, 6775 Centinela Avenue, Los Angeles, Los Angeles County, CA
Detail of main entrance on northwest side of building, camera ...
Detail of main entrance on northwest side of building, camera facing southeast - Golden Gate International Exposition, Palace of Fine and Decorative Arts & Annex, California Avenue, Treasure Island, San Francisco, San Francisco County, CA
31. VIEW OF CONCRETE SLAB AT WEST ENTRANCE OF WALKWAY. '1944 JOE LANDETA' SCRATCHED INTO FRESH CONCRETE. March 1987 - Verde River Sheep Bridge, Spanning Verde River (Tonto National Forest), Cave Creek, Maricopa County, AZ
2. EXTERIOR VIEW OF HILLSIDE PLANT ENTRANCE. NOTE CONTRAST BETWEEN THIS MODERN ADDITION AND THE OLDER SECTION OF THE MILL VISIBLE IN HAER No. GA-130-1. - Hillside Cotton Mill, 1300 Brownwood Avenue, La Grange, Troup County, GA
INTERIOR VIEW, STAIRWAY WITH ENTRANCE AND PALLADIAN WINDOW IN BACKGROUND, FACING SOUTHEAST. - Southern Branch of the National Home for Disabled Volunteer Soldiers, Building 69, Harris Avenue, Hampton, Hampton, VA
South side (red cross office entrance). Fitzsimons General Hospital, ...
South side (red cross office entrance). - Fitzsimons General Hospital, Red Cross Building, South Eighth Street Bounded by West McAfee Avenue on South & West Harlow Avenue on North, Aurora, Adams County, CO
A compact imaging spectrometer comprises an entrance slit, a catadioptric lens with a mirrored surface, a grating, and a detector array. The entrance slit directs light to the mirrored surface of the catadioptric lens; the mirrored surface reflects the light back through the lens to the grating. The grating receives the light from the catadioptric lens and diffracts the light to the lens away from the mirrored surface. The lens transmits the light and focuses it onto the detector array.
Chrisp, Michael P. (Danville, CA); Lerner, Scott A. (Corvallis, OR)
Elevation and plan of east side entrance. San Bernardino Valley ...
Elevation and plan of east side entrance. San Bernardino Valley Union Junior College, Library Building. Also includes sections II and SS of entrance hall; and a stress diagram of steel truss. Howard E. Jones, Architect, San Bernardino, California. Sheet 7, job no. 315. Scale 1/2 inch to the foot. No date given on sheet (probably March or April, 1927). - San Bernardino Valley College, Library, 701 South Mount Vernon Avenue, San Bernardino, San Bernardino County, CA
Role of Endogenous Abscisic Acid in Potato Microtuber Dormancy.
Potato (Solanum tuberosum L. cv Russet Burbank) microtubers generated in vitro from single-node explants contained substantial amounts (approximately 250 pmol/g fresh weight) of free abscisic acid (ABA) and were completely dormant for a minimum of 12 weeks. Microtubers that developed in the presence of 10 [mu]M fluridone (FLD) contained considerably reduced amounts (approximately 5-25 pmol/g fresh weight) of free ABA and exhibited a precocious loss of dormancy. Inclusion of exogenous racemic ABA in the FLD-containing medium suppressed the premature sprouting of these microtubers in a dose-dependent manner. At a concentration of 50 [mu]M, exogenous ABA restored internal ABA levels to control values and completely inhibited FLD-induced precocious sprouting. Exogenous jasmonic acid was ineffective in suppressing FLD-induced sprouting. Application of FLD to preformed, fully dormant microtubers also resulted in a reduction in internal ABA content and precocious sprouting. These results indicate that endogenous ABA is essential for the induction and maintenance of potato microtuber dormancy.
Suttle, J. C.; Hultstrand, J. F.
Co-adaptation of seed dormancy and flowering time in the arable weed Capsella bursa-pastoris (shepherd's purse)
Background and Aims The duration of the plant life cycle is an important attribute that determines fitness and coexistence of weeds in arable fields. It depends on the timing of two key life-history traits: time from seed dispersal to germination and time from germination to flowering. These traits are components of the time to reproduction. Dormancy results in reduced and delayed germination, thus increasing time to reproduction. Genotypes in the arable seedbank predominantly have short time to flowering. Synergy between reduced seed dormancy and reduced flowering time would create stronger contrasts between genotypes, offering greater adaptation in-field. Therefore, we studied differences in seed dormancy between in-field flowering time genotypes of shepherd's purse. Methods Genotypes with early, intermediate or late flowering time were grown in a glasshouse to provide seed stock for germination tests. Secondary dormancy was assessed by comparing germination before and after dark-incubation. Dormancy was characterized separately for seed myxospermy heteromorphs, observed in each genotype. Seed carbon and nitrogen content and seed mass were determined as indicators of seed filling and resource partitioning associated with dormancy. Key Results Although no differences were observed in primary dormancy, secondary dormancy was weaker among the seeds of early-flowering genotypes. On average, myxospermous seeds showed stronger secondary dormancy than non-myxospermous seeds in all genotypes. Seed filling was similar between the genotypes, but nitrogen partitioning was higher in early-flowering genotypes and in non-myxospermous seeds. Conclusions In shepherd's purse, early flowering and reduced seed dormancy coincide and appear to be linked. The seed heteromorphism contributes to variation in dormancy. Three functional groups of seed dormancy were identified, varying in dormancy depth and nitrate response. One of these groups (FG-III) was distinct for early-flowering genotypes. The weaker secondary dormancy of early-flowering genotypes confers a selective advantage in arable fields.
Toorop, Peter E.; Campos Cuerva, Rafael; Begg, Graham S.; Locardi, Bruna; Squire, Geoff R.; Iannetta, Pietro P. M.
Association of seed dormancy with shattering, awn, and black hull and red pericarp colors enhances survival of wild and weedy species, but challenges the use of dormancy genes in breeding varieties resistant to preharvest sprouting. A phenotypic selection and recurrent backcrossing technique was used to introduce dormancy genes from a wild-like weedy rice to a breeding line to determine their effects and linkage with the other traits. Five generations of phenotypic selection alone for low germination extremes simultaneously retained dormancy alleles at five independent QTL, including qSD12 (R2 > 50%), as determined by genome-wide scanning for their main and/or epistatic effects in two BC4F2 populations. Four dormancy loci with moderate to small effects colocated with QTL/genes for one to three of the associated traits. Multilocus response to the selection suggests that these dormancy genes are cumulative in effect, as well as networked by epistases, and that the network may have played a "sheltering" role in maintaining intact adaptive haplotypes during the evolution of weeds. Tight linkage may prevent the dormancy genes from being used in breeding programs. The major effect of qSD12 makes it an ideal target for map-based cloning and the best candidate for imparting resistance to preharvest sprouting.
Gu, Xing-You; Kianian, Shahryar F.; Foley, Michael E.
Phenotypic selection for dormancy introduced a set of adaptive haplotypes from weedy into cultivated rice.
Association of seed dormancy with shattering, awn, and black hull and red pericarp colors enhances survival of wild and weedy species, but challenges the use of dormancy genes in breeding varieties resistant to preharvest sprouting. A phenotypic selection and recurrent backcrossing technique was used to introduce dormancy genes from a wild-like weedy rice to a breeding line to determine their effects and linkage with the other traits. Five generations of phenotypic selection alone for low germination extremes simultaneously retained dormancy alleles at five independent QTL, including qSD12 (R(2) > 50%), as determined by genome-wide scanning for their main and/or epistatic effects in two BC(4)F(2) populations. Four dormancy loci with moderate to small effects colocated with QTL/genes for one to three of the associated traits. Multilocus response to the selection suggests that these dormancy genes are cumulative in effect, as well as networked by epistases, and that the network may have played a "sheltering" role in maintaining intact adaptive haplotypes during the evolution of weeds. Tight linkage may prevent the dormancy genes from being used in breeding programs. The major effect of qSD12 makes it an ideal target for map-based cloning and the best candidate for imparting resistance to preharvest sprouting. PMID:15972459
Gu, Xing-You; Kianian, Shahryar F; Foley, Michael E
Mapping of a major locus controlling seed dormancy using backcrossed progenies in wheat (Triticum aestivum L.).
Seed dormancy is an important factor regulating preharvest sprouting (PHS) but is a complex trait for genetic analysis. We previously identified a major quantitative trait locus (QTL) controlling seed dormancy on the long arm of chromosome 4A (4AL) in common wheat. To transfer the QTL from the dormant lines 'OS21-5' and 'Leader' into the Japanese elite variety 'Haruyokoi', which has an insufficient level of seed dormancy, backcrossing was carried out through marker-assisted selection (MAS) using PCR-based codominant markers. Nineteen BC5F2 plants with homozygous alleles of 'OS21-5' or 'Haruyokoi' were developed and evaluated for seed dormancy under greenhouse conditions. The seeds harvested from plants with 'OS21-5' alleles showed a clearly high level of dormancy compared with seeds from plants with 'Haruyokoi' alleles. Additionally, the dormancy phenotype of BC3F3 seeds harvested from 128 BC3F2 plants with homozygous alleles of 'Leader' or 'Haruyokoi' showed a clear difference between these alleles. The QTL on 4AL confers a major gene, Phs1, which was mapped within a 2.6 cM region. The backcrossed lines developed in this study can be important sources for improving PHS resistance in Japanese wheat and for analyzing the mechanism of seed dormancy. MAS was useful for the development of near-isogenic lines in this complex trait, to facilitate the molecular dissection of genetic factors. PMID:18521121
Torada, Atsushi; Koike, Michiya; Ikeguchi, Shojiro; Tsutsui, Ichiro
Dependency of seed dormancy types on embryo traits and environmental conditions in Ribes species.
The hypothesis that seed dormancy may be dependent on environmental conditions and seed morphological traits was tested for six Ribes species, across an altitudinal gradient of 1300 m and a longitudinal separation of 120°. Embryo measurements and seed germination experiments were conducted for R. alpinum L., R. hudsonianum Richardson var. petiolare (Douglas) Jancz., R. nevadaense Kellogg, R. roezlii Regel var. cruentum (Greene) Rehder and R. speciosum Pursh, and data taken from the literature for R. multiflorum Kit. ex Schult. ssp. sandalioticum Arrigoni. Germination was compared with seed viability to reveal proportional seed dormancy, which was then correlated to seed/embryo morphological traits and these traits related to the seed provenance environment. The embryos of all the investigated species are linear underdeveloped and all had a morphological component of seed dormancy (MD). Seeds of R. roezlii, R. hudsonianum and R. nevadaense required a temperature and/or hormone pre-treatment in order to germinate, highlighting morphophysiological seed dormancy (MPD). Seed dormancy was found to be strongly negatively correlated with embryo length, but not with embryo to seed (E:S) ratio or seed mass. Initial embryo length was positively related to mean annual temperature. Seed dormancy in the investigated Ribes species could be quantified and predicted by the interaction of embryo traits and environmental conditions. This approach may be helpful in assessing and predicting seed dormancy in the Ribes genus and in other genera and families with underdeveloped embryos. PMID:24138146
Mattana, E; Stuppy, W H; Fraser, R; Waller, J; Pritchard, H W
Temperature rather than photoperiod controls growth cessation and dormancy in Sorbus species
Environmental regulation of growth and dormancy of four Sorbus genotypes was studied in controlled environments. Emphasis was placed on assessment of the presence and nature of the deficient photoperiodic dormancy regulation system that has previously been reported for some woody Rosaceae species. Two genotypes of Sorbus aucuparia L. maintained indeterminate growth for 8 weeks and 9 weeks at temperatures of 15 °C and 21 °C in both 20 h and 10 h photoperiods, while at 9 °C, in the same photoperiodic conditions, they immediately ceased growing. At the higher temperatures, initiation of new leaves (nodes) was unaffected by photoperiod, while internode elongation was significantly enhanced by long days (LD). However, even after prolonged exposure to 9 °C, most plants resumed growth when moved to high temperature and LD, indicating a shallow state of dormancy. Seedlings of Sorbus intermedia (J. F. Ehrh.) Pers. and micro-propagated plantlets of S. commixta Hedl. 'Dodong' were also unaffected by photoperiod during primary growth, but failed to elongate and gradually became dormant regardless of temperature and day-length conditions. However, after chilling and breaking of dormancy, the plants elongated vigorously but changed to a determinate mode of growth. Furthermore, a temperature of 9 °C was found to be fully effective for breaking dormancy in S. intermedia plants. It is concluded that deficient photoperiodic dormancy control seems widespread in the Rosaceae and that, in such plants, both dormancy induction and release is brought about by low temperature. The potential impacts of climate change on such trees are discussed.
Heide, Ola M.
Seed Anatomy and Water Uptake in Relation to Seed Dormancy in Opuntia tomentosa (Cactaceae, Opuntioideae)
Background and Aims There is considerable confusion in the literature concerning impermeability of seeds with 'hard' seed coats, because the ability to take up (imbibe) water has not been tested in most of them. Seeds of Opuntia tomentosa were reported recently to have a water-impermeable seed coat sensu lato (i.e. physical dormancy), in combination with physiological dormancy. However, physical dormancy is not known to occur in Cactaceae. Therefore, the aim of this study was to determine if seeds of O. tomentosa are water-permeable or water-impermeable, i.e. if they have physical dormancy. Methods The micromorphology of the seed coat and associated structures were characterized by SEM and light microscopy. Permeability of the seed-covering layers was assessed by an increase in mass of seeds on a wet substrate and by dye-tracking and uptake of tritiated water by intact versus scarified seeds. Key Results A germination valve and a water channel are formed in the hilum–micropyle region during dehydration and ageing in seeds of O. tomentosa. The funicular envelope undoubtedly plays a role in germination of Opuntia seeds via restriction of water uptake and mechanical resistance to expansion of the embryo. However, seeds do not exhibit any of three features characteristic of those with physical dormancy. Thus, they do not have a water-impermeable layer(s) of palisade cells (macrosclereids) or a water gap sensu stricto and they imbibe water without the seed coat being disrupted. Conclusions Although dormancy in seeds of this species can be broken by scarification, they have physiological dormancy only. Further, based on information in the literature, it is concluded that it is unlikely that any species of Opuntia has physical dormancy. This is the first integrative study of the anatomy, dynamics of water uptake and dormancy in seeds of Cactaceae subfamily Opuntioideae.
Orozco-Segovia, A.; Marquez-Guzman, J.; Sanchez-Coronado, M. E.; Gamboa de Buen, A.; Baskin, J. M.; Baskin, C. C.
Opposite Effects of Daylength and Temperature on Flowering and Summer Dormancy of Poa bulbosa
• Background and Aims The timing of flowering and summer dormancy induction plays a central role in the adaptation of Mediterranean geophytes to changes in the length of the growth season along rainfall gradients. Our aim was to analyse the role of the variation in the responses of flowering and summer dormancy to vernalization, daylength and growth temperature for the adaptation of Poa bulbosa, a perennial geophytic grass, to increasing aridity. • Methods Flowering and dormancy were studied under controlled daylengths [9?h short day (SD) vs. 16?h long day (LD)] and temperatures (16/10, 22/16 and 28/22?°C day/night) in four ecotypes originating in arid, semi-arid and mesic habitats (110, 276 and 810?mm rain year?1, respectively) and differing in flowering capacity under natural conditions: arid–flowering, semi-arid–flowering, semi-arid–non-flowering and mesic–non-flowering. • Key Results Flowering and dormancy were affected in opposite ways by daylength and growth temperature. Flowering occurred almost exclusively under SD. In contrast, plants became dormant much earlier under LD than under SD. In both daylengths, high temperature and pre-chilling (6 weeks at 5?°C) enhanced dormancy imposition, but inhibited or postponed flowering, respectively. Induction of flowering and dormancy in the different ecotypes showed differential responsiveness to daylength and temperature. Arid and semi-arid ecotypes had a higher proportion of flowering plants and flowering tillers as well as more panicles per plant than mesic ecotypes. 'Flowering' ecotypes entered dormancy earlier than 'non-flowering' ecotypes, while the more arid the site of ecotype origin, the earlier the ecotype entered dormancy. • Conclusions Variation in the flowering capacity of ecotypes differing in drought tolerance was interpreted as the result of balanced opposite effects of daylength and temperature on the flowering and dormancy processes.
Regional trends for bud burst and flowering of woody plants in Norway as related to climate change.
Data series for bud burst, beginning of flowering and petal fall for 20 species of deciduous trees and conifers at four sites in different regions of southern Norway have been analysed and related to temperature series. On average, the spring phenophases occurred 7 days earlier during the period 1971-2005. The most significant linear trends were observed for the earliest phases. The trends in this period were compared with trends in other periods, the longest one starting in 1927. Those starting in cold decades and ending in 2005 were in most instances statistically significant, whereas hardly any significant trend appeared for series starting in warm decades. This fact showed that the results of trend studies are very sensitive to the choice of starting year. There were significant decadal variations in 40% of the series. The dates of occurrence of the phenophases, varying from the first days of May to the first days of June, correlated with seasonal temperature series, in most cases strongest to mean temperatures for the seasons March-May and April-May. The North Atlantic Oscillation Index (NAOI) for January and February appeared to have some predictive power for the date of occurrence of the recorded phases. The basis for this may be that the oscillations described by the index are of importance for the fulfilment of physiological chilling requirements needed to break bud dormancy. The same genotypes of the trees were grown in region West Norway and in Central Norwegian region; during the period 1965-2005 the trends towards earlier bud burst were more pronounced and steeper at the western site. PMID:18418631
Nordli, Ř; Wielgolaski, F E; Bakken, A K; Hjeltnes, S H; Mĺge, F; Sivle, A; Skre, O
Auxin controls seed dormancy through stimulation of abscisic acid signaling by inducing ARF-mediated ABI3 activation in Arabidopsis.
The transition from dormancy to germination in seeds is a key physiological process during the lifecycle of plants. Abscisic acid (ABA) is the sole plant hormone known to maintain seed dormancy; it acts through a gene expression network involving the transcription factor ABSCISIC ACID INSENSITIVE 3 (ABI3). However, whether other phytohormone pathways function in the maintenance of seed dormancy in response to environmental and internal signals remains an important question. Here, we show that the plant growth hormone auxin, which acts as a versatile trigger in many developmental processes, also plays a critical role in seed dormancy in Arabidopsis. We show that disruptions in auxin signaling in MIR160-overexpressing plants, auxin receptor mutants, or auxin biosynthesis mutants dramatically release seed dormancy, whereas increases in auxin signaling or biosynthesis greatly enhance seed dormancy. Auxin action in seed dormancy requires the ABA signaling pathway (and vice versa), indicating that the roles of auxin and ABA in seed dormancy are interdependent. Furthermore, we show that auxin acts upstream of the major regulator of seed dormancy, ABI3, by recruiting the auxin response factors AUXIN RESPONSE FACTOR 10 and AUXIN RESPONSE FACTOR 16 to control the expression of ABI3 during seed germination. Our study, thus, uncovers a previously unrecognized regulatory factor of seed dormancy and a coordinating network of auxin and ABA signaling in this important process. PMID:23986496
Liu, Xiaodong; Zhang, Hong; Zhao, Yang; Feng, Zhengyan; Li, Qun; Yang, Hong-Quan; Luan, Sheng; Li, Jianming; He, Zu-Hua
Auxin controls seed dormancy through stimulation of abscisic acid signaling by inducing ARF-mediated ABI3 activation in Arabidopsis
The transition from dormancy to germination in seeds is a key physiological process during the lifecycle of plants. Abscisic acid (ABA) is the sole plant hormone known to maintain seed dormancy; it acts through a gene expression network involving the transcription factor ABSCISIC ACID INSENSITIVE 3 (ABI3). However, whether other phytohormone pathways function in the maintenance of seed dormancy in response to environmental and internal signals remains an important question. Here, we show that the plant growth hormone auxin, which acts as a versatile trigger in many developmental processes, also plays a critical role in seed dormancy in Arabidopsis. We show that disruptions in auxin signaling in MIR160-overexpressing plants, auxin receptor mutants, or auxin biosynthesis mutants dramatically release seed dormancy, whereas increases in auxin signaling or biosynthesis greatly enhance seed dormancy. Auxin action in seed dormancy requires the ABA signaling pathway (and vice versa), indicating that the roles of auxin and ABA in seed dormancy are interdependent. Furthermore, we show that auxin acts upstream of the major regulator of seed dormancy, ABI3, by recruiting the auxin response factors AUXIN RESPONSE FACTOR 10 and AUXIN RESPONSE FACTOR 16 to control the expression of ABI3 during seed germination. Our study, thus, uncovers a previously unrecognized regulatory factor of seed dormancy and a coordinating network of auxin and ABA signaling in this important process.
On the Entrance Phase in Long Rod Penetration
The penetration of long rods into semi-infinite targets is a three-stage process, in which the first (entrance) and last are very short, and transient, while the second phase (primary penetration) is a long and quasi-steady process. The present paper summarizes our recent work on the entrance phase using 2D numerical simulations of strengthless steel rods (L/D=5-20) impacting aluminum targets at 1-4 km/s. We look for the significance of this phase as impact velocity, target strength, and penetrator's length are increased. We also show that the target free surface (impact face) is not the cause for the entrance phase. Rather, it is the passage from a cylindrically-shaped to a mushroom-shaped penetrator nose which is responsible for this phase.
Rosenberg, Z.; Dekel, E.
An Experimental Investigation of NACA Submerged-Duct Entrances
The results of a preliminary investigation of submerged duct entrances are presented. It is shown that an entrance of this type possess desirable critical speed and pressure recovery characteristics when used on a fuselage or nacelle in a region of low incremental velocity and thin boundary layer. The data obtained indicate that submerged entrances are most suitable for use with internal-flow systems which diffuse the air only a small amount: for example, those used with jet motors which have axial-flow compressors. Where complete diffusion of the air is required, fuselage-nose or wing leading edge inlets may prove to be superior. The results of the investigation have been prepared in such a form as to permit their use by a designer and the application of these data to a specific design is discussed.
Frick, Charles W.; Davis, Wallace F.; Randall, Lauros M.; Mossman, Emmet A.
Breaking Cancer Dormancy to Sensitize Dormant Breast Cancer Cells to Cytotoxic Chemotherapy.
Patients with breast cancer can develop recurrent metastatic disease with latency periods that range from years to decades. This pause can be explained by micrometastatic disseminated tumor cell (DTC) dormancy, a stage in cancer progression in which resid...
D. Tran
Identification of an Amphipathic Helix Important for the Formation of Ectopic Septin Spirals and Axial Budding in Yeast Axial Landmark Protein Bud3p
Correct positioning of polarity axis in response to internal or external cues is central to cellular morphogenesis and cell fate determination. In the budding yeast Saccharomyces cerevisiae, Bud3p plays a key role in the axial bud-site selection (axial budding) process in which cells assemble the new bud next to the preceding cell division site. Bud3p is thought to act as a component of a spatial landmark. However, it is not clear how Bud3p interacts with other components of the landmark, such as the septins, to control axial budding. Here, we report that overexpression of Bud3p causes the formation of small septin rings (?1 µm in diameter) and arcs aside from previously reported spiral-like septin structures. Bud3p closely associates with the septins in vivo as Bud3p colocalizes with these aberrant septin structures and forms a complex with two septins, Cdc10p and Cdc11p. The interaction of Bud3p with the septins may involve multiple regions of Bud3p including 1–858, 850–1220, and 1221–1636 a.a. since they all target to the bud neck but exhibit different effects on septin organization when overexpressed. In addition, our study reveals that the axial budding function of Bud3p is mediated by the N-terminal region 1–858. This region shares an amphipathic helix (850–858) crucial for bud neck targeting with the middle portion 850–1103 involved in the formation of ectopic septin spirals and rings. Interestingly, the Dbl-homology domain located in 1–858 is dispensable for axial bud-site selection. Our findings suggest that multiple regions of Bud3p ensure efficient targeting of Bud3p to the bud neck in the assembly of the axial landmark and distinct domains of Bud3p are involved in axial bud-site selection and other cellular processes.
Guo, Jia; Gong, Ting; Gao, Xiang-Dong
Dormancy in white-grained wheat: Progress towards identification of genes and molecular markers
Preharvest sprouting limits the consistent production of high quality wheat in many regions of the world. Improvements in\\u000a tolerance from the introduction of better grain dormancy at, or near, harvest-ripeness would be expected to have a significant\\u000a impact on the incidence and severity of sprouting. Genetic and molecular investigations have provided new evidence for the\\u000a presence of dormancy genes on
Daryl Mares; Kolumbina Mrva; Mui-Keng Tan; Peter Sharp
One phase of the dormancy developmental pathway is critical for the evolution of insect seasonality.
Evolutionary change in the timing of dormancy enables animals and plants to adapt to changing seasonal environments and can result in ecological speciation. Despite its clear biological importance, the mechanisms underlying the evolution of dormancy timing in animals remain poorly understood because of a lack of anatomical landmarks to discern which phase of dormancy an individual is experiencing. Taking advantage of the nearly universal characteristic of metabolic suppression during insect dormancy (diapause), we use patterns of respiratory metabolism to document physiological landmarks of dormancy and test which of the distinct phases of the dormancy developmental pathway contribute to a month-long shift in diapause timing between a pair of incipient moth species. Here, we show that divergence in life cycle between the earlier-emerging E-strain and the later-emerging Z-strain of European corn borer (ECB) is clearly explained by a delay in the timing of the developmental transition from the diapause maintenance phase to the termination phase. Along with recent findings indicating that life-cycle differences between ECB strains stem from allelic variation at a single sex-linked locus, our results demonstrate how dramatic shifts in animal seasonality can result from simple developmental and genetic changes. Although characterizing the multiple phases of the diapause developmental programme in other locally adapted populations and species will undoubtedly yield surprises about the nature of animal dormancy, results in the ECB moth suggest that focusing on genetic variation in the timing of the dormancy termination phase may help explain how (or whether) organisms rapidly respond to global climate change, expand their ranges after accidental or managed introductions, undergo seasonal adaptation, or evolve into distinct species through allochronic isolation. PMID:24016035
Wadsworth, C B; Woods, W A; Hahn, D A; Dopman, E B
Effect of storage temperature and extraction methods on dormancy and germination of true potato seed
Seed treatments, methods of extraction and storage temperature were examined for effects on viability and dormancy of true\\u000a potato seed. Dormancy of 4x?2x (S. tuberosum ×S. phureja) hybrids was eliminated after 7 months at room temperature and after 10 months at 4 C. However, data on the velocity and\\u000a uniformity of germination (coefficient of velocity) revealed the presence of a
Vincent L. D'Antonio; Neil A. McHale
Genes controlling seed dormancy and pre-harvest sprouting in a rice-wheat-barley comparison
Pre-harvest sprouting results in significant economic loss for the grain industry around the world. Lack of adequate seed dormancy is the major reason for pre-harvest sprouting in the field under wet weather conditions. Although this trait is governed by multiple genes it is also highly heritable. A major QTL controlling both pre-harvest sprouting and seed dormancy has been identified on
Chengdao Li; Peixiang Ni; Michael Francki; Adam Hunter; Yong Zhang; David Schibeci; Heng Li; Allen Tarr; Jun Wang; Mehmet Cakir; Jun Yu; Matthew Bellgard; Reg Lance; Rudi Appels
Identification of genomic regions associated with seed dormancy in white-grained wheat
Pre-harvest sprouting (PHS) in developing wheat (Triticum aestivum L.) spikes is stimulated by cool and wet weather and leads to a decline in grain quality. A low level of harvest-time seed\\u000a dormancy is a major factor for PHS, which generally is a larger problem in white-grained as compared to red-grained wheat.\\u000a We have in this study analyzed seed dormancy levels
Rajender Singh; Maria Matus-Cádiz; Monica Bĺga; Pierre Hucl; Ravindra N. Chibbar
Proteins and polyamines during dormancy breaking of European beech ( Fagus sylvatica L.) seeds
The studies were carried out on Fagus sylvatica seeds during stratification and their germination. After imbibition beechnuts were subjected to cold (3 °C — temperature\\u000a which breaks dormancy) or warm (15 °C — temperature unable to break dormancy) stratification and alternatively were treated\\u000a with polyamine synthesis inhibitors: canavanine and DFMO (difluoromethylornithine). After cold stratification in embryo axes\\u000a we found (using
Zofia Szczotka; Tomasz Paw?owski; Kazimierz Krawiarz
Different requirements for physical dormancy release in two populations of Sophora alopecuroides relation to burial depth
Most species of Fabaceae produce seeds with physical dormancy which was broken by some environmental factors in the field, yet for the mechanism of\\u000a physical dormancy release in the natural condition is still poorly understood. In present study, seeds of Sophora alopecuroides from two populations were placed on the soil surface or buried at depths of 2 and 7 cm in
Xiao Wen Hu; Yan Pei Wu; Yan Rong Wang
Optimum harvesting time of herbaceous peony buds for cutting flowers
The herbaceous peony is one of the cut flowers that has become increasingly popular in the international market in recent\\u000a years. In the study, 11 cultivars of herbaceous peonies suitable for cutting flowers were selected; different harvesting stages\\u000a (three or four stages) were identified according to bud development observation (bud firmness, bud diameter, sepal angle,\\u000a petal angle, and color showing).
Xiao-nan Yu; Peng-peng Guo; Guang-pei Lu; Qi-xiang Zhang
Cell Polarization and Cytokinesis in Budding Yeast
Asymmetric cell division, which includes cell polarization and cytokinesis, is essential for generating cell diversity during development. The budding yeast Saccharomyces cerevisiae reproduces by asymmetric cell division, and has thus served as an attractive model for unraveling the general principles of eukaryotic cell polarization and cytokinesis. Polarity development requires G-protein signaling, cytoskeletal polarization, and exocytosis, whereas cytokinesis requires concerted actions of a contractile actomyosin ring and targeted membrane deposition. In this chapter, we discuss the mechanics and spatial control of polarity development and cytokinesis, emphasizing the key concepts, mechanisms, and emerging questions in the field.
Bi, Erfei; Park, Hay-Oak
Transcriptional changes induced by the tumor dormancy-associated microRNA-190
Tumor dormancy is a highly prevalent stage in cancer progression. We have previously generated and characterized in vivo experimental models of human tumor dormancy in which micro-tumors remain occult until they spontaneously shift into rapid tumor growth. We showed that the dormant micro-tumors undergo a stable microRNA (miRNA) switch during their transition from dormancy to a fast-growing phenotype and reported the identification of a consensus signature of human tumor dormancy-associated miRNAs (DmiRs). miRNA-190 (miR-190) is among the most upregulated DmiRs in all dormant tumors analyzed. Upregulation of miR-190 led to prolonged tumor dormancy in otherwise fast-growing glioblastomas and osteosarcomas. Here we investigate the transcriptional changes induced by miR-190 expression in cancer cells and show similar patterns of miR-190 mediated transcriptional reprogramming in both glioblastoma and osteosarcoma cells. The data suggests that miR-190 mediated effects rely on an extensive network of molecular changes in tumor cells and that miR-190 affects several transcriptional factors, tumor suppressor genes and interferon response pathways. The molecular mechanisms governing tumor dormancy described in this work may provide promising targets for early prevention of cancer and may lead to novel treatments to convert the malignant tumor phenotype into an asymptomatic dormant state.
Almog, Nava; Briggs, Christine; Beheshti, Afshin; Ma, Lili; Wilkie, Kathleen P.; Rietman, Edward; Hlatky, Lynn
Multiple loci and epistases control genetic variation for seed dormancy in weedy rice (Oryza sativa).
Weedy rice has much stronger seed dormancy than cultivated rice. A wild-like weedy strain SS18-2 was selected to investigate the genetic architecture underlying seed dormancy, a critical adaptive trait in plants. A framework genetic map covering the rice genome was constructed on the basis of 156 BC(1) [EM93-1 (nondormant breeding line)//EM93-1/SS18-2] individuals. The mapping population was replicated using a split-tiller technique to control and better estimate the environmental variation. Dormancy was determined by germination of seeds after 1, 11, and 21 days of after-ripening (DAR). Six dormancy QTL, designated as qSD(S)-4, -6, -7-1, -7-2, -8, and -12, were identified. The locus qSD(S)-7-1 was tightly linked to the red pericarp color gene Rc. A QTL x DAR interaction was detected for qSD(S)-12, the locus with the largest main effect at 1, 11, and 21 DAR (R(2) = 0.14, 0.24, and 0.20, respectively). Two, three, and four orders of epistases were detected with four, six, and six QTL, respectively. The higher-order epistases strongly suggest the presence of genetically complex networks in the regulation of variation for seed dormancy in natural populations and make it critical to select for a favorable combination of alleles at multiple loci in positional cloning of a target dormancy gene.
The qSD12 Locus Controls Offspring Tissue-Imposed Seed Dormancy in Rice
Seed component structures were grouped into maternal and offspring (embryo and endosperm) tissues to characterize a dormancy quantitative trait locus (QTL) for tissue-specific function using a marker-assisted genetic approach. The approach was devised to test if genotypic/allelic frequencies of a marker tightly linked to the QTL deviate from Mendelian expectations in germinated and nongerminated subpopulations derived from a segregation population of partially after-ripened seeds and was applied to the dormancy QTL qSD12 and qSD7-1 in a nearly isogenic background of rice. Experimental results unambiguously demonstrated that qSD12 functions in the offspring tissue(s) and suggested that qSD7-1 may control dormancy through the maternal tissues. These experiments also provide the first solid evidence that an offspring tissue-imposed dormancy gene contributes to the segregation distortion in a mapping population developed from partially after-ripened seeds and, in part, to the germination heterogeneity of seeds from hybrid plants. Offspring and maternal tissue-imposed dormancy genes express in very early and late stages of the life cycle, respectively, and interact to provide the species with complementary adaptation strategies. The qSD12 locus was narrowed to the region of ?600 kbp on a high-resolution map to facilitate cloning and marker-assisted selection of the major dormancy gene.
Gu, Xing-You; Turnipseed, E. Brent; Foley, Michael E.
ABA inhibits germination but not dormancy release in mature imbibed seeds of Lolium rigidum Gaud.
Dormancy release in imbibed annual ryegrass (Lolium rigidum Gaud.) seeds is promoted in the dark but inhibited in the light. The role of abscisic acid (ABA) in inhibition of dormancy release was found to be negligible, compared with its subsequent effect on germination of dormant and non-dormant seeds. Inhibitors of ABA metabolism had the expected effects on seed germination but did not influence ABA concentration, suggesting that they act upon other (unknown) factors regulating dormancy. Although gibberellin (GA) synthesis was required for germination, the influence of exogenous GA on both germination and dormancy release was minor or non-existent. Embryo ABA concentration was the same following treatments to promote (dark stratification) and inhibit (light stratification) dormancy release; exogenous ABA had no effect on this process. However, the sensitivity of dark-stratified seeds to ABA supplied during germination was lower than that of light-stratified seeds. Therefore, although ABA definitely plays a role in the germination of annual ryegrass seeds, it is not the major factor mediating inhibition of dormancy release in imbibed seeds. PMID:19487389
Goggin, Danica E; Steadman, Kathryn J; Emery, R J Neil; Farrow, Scott C; Benech-Arnold, Roberto L; Powles, Stephen B
Analysis of natural allelic variation at seed dormancy loci of Arabidopsis thaliana.
Arabidopsis accessions differ largely in their seed dormancy behavior. To understand the genetic basis of this intraspecific variation we analyzed two accessions: the laboratory strain Landsberg erecta (Ler) with low dormancy and the strong-dormancy accession Cape Verde Islands (Cvi). We used a quantitative trait loci (QTL) mapping approach to identify loci affecting the after-ripening requirement measured as the number of days of seed dry storage required to reach 50% germination. Thus, seven QTL were identified and named delay of germination (DOG) 1-7. To confirm and characterize these loci, we developed 12 near-isogenic lines carrying single and double Cvi introgression fragments in a Ler genetic background. The analysis of these lines for germination in water confirmed four QTL (DOG1, DOG2, DOG3, and DOG6) as showing large additive effects in Ler background. In addition, it was found that DOG1 and DOG3 genetically interact, the strong dormancy determined by DOG1-Cvi alleles depending on DOG3-Ler alleles. These genotypes were further characterized for seed dormancy/germination behavior in five other test conditions, including seed coat removal, gibberellins, and an abscisic acid biosynthesis inhibitor. The role of the Ler/Cvi allelic variation in affecting dormancy is discussed in the context of current knowledge of Arabidopsis germination.
Alonso-Blanco, Carlos; Bentsink, Leonie; Hanhart, Corrie J; Blankestijn-de Vries, Hetty; Koornneef, Maarten
Genetic basis of barley caryopsis dormancy and seedling desiccation tolerance at the germination stage.
The genomic regions controlling caryopsis dormancy and seedling desiccation tolerance were identified using 152 F4 lines derived from a cross between Mona, a Swedish cultivar, and an Israeli xeric wild barley Hordeum spontaneum genotype collected at Wadi Qilt, Israel. Dormancy, the inability of a viable seed to germinate, and desiccation tolerance, the ability of the desiccated seedlings to revive after rehydration, were characterized by fitting the germination and revival data with growth curves, using three parameters: minimum, maximum, and slope of germination or revival rate derived by the least square method. The genetic map was constructed with 85 genetic markers (SSRs, AFLPs, STSs, and Dhn genes) using the MULTIPOINT: -mapping algorithm. Quantitative trait loci (QTLs) mapping was conducted with the MULTIQTL: package. Ten genomic regions were detected that affected the target traits, seven of which affected both dormancy and desiccation tolerance traits. Both the wild barley genotype and the Swedish cultivar contributed the favorite alleles for caryopsis dormancy, whereas seedling desiccation tolerance was attributed to alleles descending from the cultivar. The results indicate that some barley dormancy genes are lost during domestication and that dormancy QTLs are associated with abiotic stress tolerance. PMID:15565376
Zhang, F; Chen, G; Huang, Q; Orion, O; Krugman, T; Fahima, T; Korol, A B; Nevo, E; Gutterman, Y
The hormonal regulation of axillary bud growth in Arabidopsis.
Apically derived auxin has long been known to inhibit lateral bud growth, but since it appears not to enter the bud, it has been proposed that its inhibitory effect is mediated by a second messenger. Candidates include the plant hormones ethylene, cytokinin and abscisic acid. We have developed a new assay to study this phenomenon using the model plant Arabidopsis. The assay allows study of the effects of both apical and basal hormone applications on the growth of buds on excised nodal sections. We have shown that apical auxin can inhibit the growth of small buds, but larger buds were found to have lost competence to respond. We have used the assay with nodes from wild-type and hormone-signalling mutants to test the role of ethylene, cytokinin and abscisic acid in bud inhibition by apical auxin. Our data eliminate ethylene as a second messenger for auxin-mediated bud inhibition. Similarly, abscisic acid signalling is not to be required for auxin action, although basally applied abscisic can enhance inhibition by apical auxin and apically applied abscisic acid can reduce it. By contrast, basally applied cytokinin was found to release lateral buds from inhibition by apical auxin, while apically applied cytokinin dramatically increased the duration of inhibition. These results are consistent with cytokinin acting independently to regulate bud growth, rather than as a second messenger for auxin. However, in the absence of cytokinin-signalling mutants, a role for cytokinin as a second messenger for auxin cannot be ruled out. PMID:11069691
Chatfield, S P; Stirnberg, P; Forde, B G; Leyser, O
Dormancy effects on the reliability of nuclear thermal propulsion systems for long-term manned space missions
This paper explores the effects of dormancy on the reliability of a Nuclear Thermal Propulsion (NTP) system for long-term manned space missions, such as Mars exploration. Dormancy refers to the portion of space systems operation where the power and stress levels are significantly reduced from nominal values and the authors have identified dormancy as a significant effect. Three approaches are used to evaluate the relative importance of failure rates during dormant operation: use of failure rate models involving dormancy, power cycling and fully energized operation; study of data bases which include both dormant and energized failure rates; predictions based on an Arrhenius rate process formulation. The results of these approaches suggest that for a long term manned mission the dormancy, cycle, and energized failure rates will all be important. Reliability in the energized state normally receives utmost attention and care during design, however, unless equal attention is directed to dormancy, the mission reliability may be severely compromised.
Shooman, Martin L.; Sforza, Pasquale M.
Overexpression of Constans Homologs CO1 and CO2 Fails to Alter Normal Reproductive Onset and Fall Bud Set in Woody Perennial Poplar
CONSTANS (CO) is an important flowering-time gene in the photoperiodic flowering pathway of annual Arabidopsis thaliana in which overexpression of CO induces early flowering, whereas mutations in CO cause delayed flowering. The closest homologs of CO in woody perennial poplar (Populus spp.) are CO1 and CO2. A previous report [1] showed that the CO2/FLOWERING LOCUS T1 (FT1) regulon controls the onset of reproduction in poplar, similar to what is seen with the CO/FLOWERING LOCUS T (FT) regulon in Arabidopsis. The CO2/FT1 regulon was also reported to control fall bud set. Our long-term field observations show that overexpression of CO1 and CO2 individually or together did not alter normal reproductive onset, spring bud break, or fall dormancy in poplar, but did result in smaller trees when compared with controls. Transcripts of CO1 and CO2 were normally most abundant in the growing season and rhythmic within a day, peaking at dawn. Our manipulative experiments did not provide evidence for transcriptional regulation being affected by photoperiod, light intensity, temperature, or water stress when transcripts of CO1 and CO2 were consistently measured in the morning. A genetic network analysis using overexpressing trees, microarrays, and computation demonstrated that a majority of functionally known genes downstream of CO1 and CO2 are associated with metabolic processes, which could explain their effect on tree size. In conclusion, the function of CO1 and CO2 in poplar does not appear to overlap with that of CO from Arabidopsis, nor do our data support the involvement of CO1 and CO2 in spring bud break or fall bud set.
Hsu, Chuan-Yu; Adams, Joshua P.; No, Kyoungok; Liang, Haiying; Meilan, Richard; Pechanova, Olga; Barakat, Abdelali; Carlson, John E.; Page, Grier P.; Yuceer, Cetin
A novel zinc-finger protein with a proline-rich domain mediates ABA-regulated seed dormancy in Arabidopsis
Seed dormancy is an important developmental process that prevents pre-harvest sprouting in many grains and other seeds. Abscisic acid (ABA), a plant hormone, plays a crucial role in regulating dormancy but the underlying molecular regulatory mechanisms are not fully understood. An Arabidopsis zinc-finger gene, MEDIATOR OF ABA-REGULATED DORMANCY 1(MARD1) was identified and functionally analyzed. MARD1expression is up-regulated by ABA. A
Yuehui He; Susheng Gan
Stochastic exit from mitosis in budding yeast
Unlike many mutants that are completely viable or inviable, the CLB2-db? clb5? mutant of Saccharomyces cerevisiae is inviable in glucose but partially viable on slower growth media such as raffinose. On raffinose, the mutant cells can bud and divide but in each cycle there is a chance that a cell will fail to divide (telophase arrest), causing it to exit the cell cycle. This effect gives rise to a stochastic phenotype that cannot be explained by a deterministic model. We measure the interbud times of wild-type and mutant cells growing on raffinose and compute statistics and distributions to characterize the mutant's behavior. We convert a detailed deterministic model of the budding yeast cell cycle to a stochastic model and determine the extent to which it captures the stochastic phenotype of the mutant strain. Predictions of the mathematical model are in reasonable agreement with our experimental data and suggest directions for improving the model. Ultimately, the ability to accurately model stochastic phenotypes may prove critical to understanding disease and therapeutic interventions in higher eukaryotes.
Ball, David A; Ahn, Tae-Hyuk; Wang, Pengyuan; Chen, Katherine C; Cao, Yang; Tyson, John J; Peccoud, Jean
View of main entrance of the Church of God. This ...
View of main entrance of the Church of God. This structure was originally a lodge hall for the Woodmen of the World from the adjacent mill neighborhoods such as Lincoln and Dallas Mill - 601 Humes Avenue (House), 601 Humes Avenue, Huntsville, Madison County, AL
Spatially controlled channel entrances functionalization of zeolites L.
The spatially controlled channel entrances functionalization of disk shaped zeolite L crystals is described. Fluorescent dye or bioactive molecules are immobilized at one end of the channels of zeolite crystals and subsequently the other side of the crystals is derivatized with magnetic iron oxide nanoparticles. The asymmetrically functionalized crystals were used for the control of the movement of bacteria in solution. PMID:24510774
Kehr, Nermin Seda; Ergün, Bahar; Lülf, Henning; De Cola, Luisa
42. VIEW OF MARISCAL QUICKSILVER MINE ENTRANCE TWENTY YARDS SOUTHWEST OF MAIN SHAFT LOOKING NORTHWEST. MINE CLOSURE BY PARK SERVICE, 1995. NOTE CONCRETE FOUNDATIONS IN THE CENTER OF IMAGE BEHIND OPENING FOR MAIN-SHAFT HOIST. - Mariscal Quicksilver Mine & Reduction Works, Terlingua, Brewster County, TX
Price substitutes: the case of entrance to Greek universities
This note provides evidence that the equilibrium between supply and demand in higher education in Greece is determined by what is argued to be the substitute for the non-existing market prices: the academic departments' entrance grades. This leads to the investigation of some implications of a policy change in Greek higher education.
George Gerasimou
1. OVERVIEW OF MAIN ENTRANCE TO RESORT WITH STATE HIGHWAY 89 IN FOREGROUND; MAIN LODGE IS ON THE FAR LEFT (WEST); CORD CABIN IS BEHIND AND TO THE RIGHT OF PARKED VEHICLES. - Camp Richardson Resort, Cord Cabin, U.S. Highway 89, 3 miles west of State Highway 50 & 89, South Lake Tahoe, El Dorado County, CA
3. ONTARIO MINE. ADIT ENTRANCE WITH TIN ROOF. TIP TOP IS LOCATED IN LINE WITH 'Y' BRANCH AND THE TAILING PILE FOR TIP TOP IS VISIBLE JUST TO RIGHT OF IT. CAMERA POINTED SOUTH-SOUTHEAST. - Florida Mountain Mining Sites, Ontario Mine, Northwest side of Florida Mountain, Silver City, Owyhee County, ID
VIEW OF THE FRONT ENTRANCE OF BUILDING 708. THROUGH THE WOODEN DOUBLE DOORS IS A CONFESSIONAL (LOCATED ON THE LEFT) AND A STAIR CASE (LOCATED ON THE RIGHT) WHICH LEADS TO THE CHOIR LOFT ABOVE. - U.S. Naval Base, Pearl Harbor, Chapel, Corner of Oakley & Nimitz Street, Pearl City, Honolulu County, HI
"Dog House" or vestibule at the secondstory entrance located at ...
"Dog House" or vestibule at the second-story entrance located at the intersection of the west Verandah of the south wing and the south Verandah of the rotunda extension. - U. S. Naval Asylum, Biddle Hall, Gray's Ferry Avenue, Philadelphia, Philadelphia County, PA
69. VIEW OF FOREBAY AND RESERVOIR, SHOWING FLUME ENTRANCE TO RESERVOIR ON THE RIGHT OF FOREBAY IN THE BACKGROUND (SHOWN BY THE WHITE X ON THE PHOTOGRAPHS), Print No. 191, December 1903 - Electron Hydroelectric Project, Along Puyallup River, Electron, Pierce County, WA
5. PERSPECTIVE VIEW TO THE NORTHWEST SHOWING ENTRANCE TO CREW SHELTER AND THE TAPERING SHAPE OF THE SOUTHEAST END WALL OF AR-8. - Edwards Air Force Base, South Base, Rammed Earth Aircraft Dispersal Revetments, Western Shore of Rogers Dry Lake, Boron, Kern County, CA
View of Arcade interior at entrance to Snack House Restaurant. ...
View of Arcade interior at entrance to Snack House Restaurant. Note scored plaster detail replicating stone construction joints on brick rearing walls, and detailed plaster relief panels. Various color schemed from panels and cornice details are visible throughout the building and in historic photographs - Post Office Arcade, 2118 First Street, Fort Myers, Lee County, FL
DETAIL VIEW, MAIN ENTRANCE GATES, SHOWING A WINGED HOURGLASS MOTIF, WHICH REFERS TO THE QUICK PASSAGE OF TIME AND THE SHORTNESS OF HUMAN LIFE. USE OF THIS MOTIF WAS A CARRYOVER FROM THE MCARTHUR GATES. - Woodlands Cemetery, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA
8. INTERIOR, CONTROL AND INSTRUMENTATION ROOM. Looking southwest toward entrance ...
8. INTERIOR, CONTROL AND INSTRUMENTATION ROOM. Looking southwest toward entrance and inner blast door. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA
6. INTERIOR VIEW OF NORTH ENTRANCE TO BASEMENT SHOWING WORKBENCH AT PHOTO LEFT AND ONE OF TWO DOORWAYS TO MAIN BASEMENT AREA AT PHOTO RIGHT. VIEW TO NORTH. - Bishop Creek Hydroelectric System, Control Station, Worker Cottage, Bishop Creek, Bishop, Inyo County, CA
1979 National Unified Entrance Examination for Institutions of Higher Education.
The article presents translations of Chinese college entrance examinations in the fields of politics, Chinese language and literature, mathematics, humanities, physics, chemistry, history, geography, and English. Translations are also presented of the 1979 review syllabus for 1979 for the same subject areas. (DB)
Chinese Education, 1979
39. Historic American Buildings Survey ORIGINAL DRAWING, ENTRANCE TO COLEMAN ...
39. Historic American Buildings Survey ORIGINAL DRAWING, ENTRANCE TO COLEMAN MUSEUM (1880) (FROM THE ORIGINAL IN THE OFFICE OF THE VICE PRESIDENT FOR DEVELOPMENT AND PHYSICAL PLANT, GEORGETOWN UNIVERSITY) - Georgetown University, Healy Building, Thirty-seventh & O Streets, Northwest, Washington, District of Columbia, DC
West wing. Sidewalk streetscape shows art deco entrance door to ...
West wing. Sidewalk streetscape shows art deco entrance door to service yard and access ramp (added ca. 1985) along the south façade of the west wing. - Jewish Community Center of San Francisco, 3200 California Street, San Francisco, San Francisco County, CA
Getting Interpersonal on a University Entrance Exam Impromptu Writing Task
This article explores the types of audience engagement strategies used by a Japanese secondary school student in an after school course preparing for a high-stakes impromptu academic writing task on a university entrance exam. The study uses appraisal theory--the branch of Systemic Functional Linguistics (SFL) concerned with the patterning of…
Myskow, Gordon; Gordon, Kana
DETAIL VIEW OF SIDEWALK, CLINKER BRICK RETAINING WALL, AND ENTRANCE WAY TO WILLIAM R. THORSEN HOUSE BY CHARLES & HENRY GREENE, 1909. EAST SIDE OF PIEDMONT AVENUE LOOKING SE. Photograph by Fredrica Drotos and Michael Kelly, July 9, 2006 - Piedmont Way & the Berkeley Property Tract, East of College Avenue between Dwight Way & U.C. Memorial Stadium, Berkeley, Alameda County, CA
PRIMARY ENTRANCE INTO THE JENNE FARM, WEST FAÇADE. (The Jenne ...
PRIMARY ENTRANCE INTO THE JENNE FARM, WEST FAÇADE. (The Jenne Barn has board and batten exterior cladding and sits above-grade on a poured concrete foundation. The barn is painted red with white trim. This door is painted green.) - Jenne Farm, Barn, 538 Engle Road, Coupeville, Island County, WA
Interior view, front entrance doors; note; double doors have a ...
Interior view, front entrance doors; note; double doors have a box lock, sliding bolt locks into door head and sill as well as modern locks, butt hinges, slightly recessed panels, and five-ligh transom - Fort Hill, Clemson University Campus, Clemson, Pickens County, SC
MARMION WAY AND AVENUE 66 ENTRANCE TO SOUTHBOUND LANES OF ARROYO SECO PARKWAY. NOTE SMALL ISLAND AND SHORT ACCESS LANES. SEEN FROM SAME CAMERA POSITION ON DEBS PARK HILL AS CA-265-14. LOOKING 0°N - Arroyo Seco Parkway, Marmion Way Bridge, Milepost 29.28, Los Angeles, Los Angeles County, CA
SOUTH ENTRANCE REFLECTED PLAN; DETAIL VIEW, SOUTHEAST SIDE. Glass plate ...
SOUTH ENTRANCE REFLECTED PLAN; DETAIL VIEW, SOUTHEAST SIDE. Glass plate stereopair number PA-1430-139 LC-HABS-GS05-ST-D-2 157.4709. Right (not printed) - Independence Hall Complex, Independence Hall, 500 Chestnut Street, Philadelphia, Philadelphia County, PA
SOUTH ENTRANCE REFLECTED PLAN; DETAIL VIEW, SOUTHEAST SIDE. Glass plate stereopair number PA-1430-139 LC-HABS-GS05-ST-D-2 157.4709. Left (printed) - Independence Hall Complex, Independence Hall, 500 Chestnut Street, Philadelphia, Philadelphia County, PA
8. BUILDING 332, INTERIOR, HALLWAY NEAR MAIN ENTRANCE IN NORTHWESTERN PORTION OF BUILDING, LOOKING NORTH, WITH LOBBY TO LEFT AND CONFERENCE ROOM TO RIGHT. - Oakland Naval Supply Center, Dry Provisions Storehouses, Between Third & Fourth Streets, Between G & L Street, Oakland, Alameda County, CA
5. GENERAL VIEW OF ENTRANCE ROAD SHOWING WALKWAY TO ADMINISTRATIVE SITE, INTERNAL POLICE POST AND MILITARY POLICE POST, LOOKING NORTHNORHTEAST. - Manzanar War Relocation Center, Owens Valley off U.S. Highway 395, 6 miles South of Independence, Independence, Inyo County, CA
1. EAST ENTRANCE FROM LOADING AREA. CONCRETE TUNNEL TO TEST STAND 1-3 IS AT RIGHT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Instrumentation & Control Building, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA
1. Credit PSR. This view captures the main entrance to ...
1. Credit PSR. This view captures the main entrance to the Administration/Shops Building, constructed in 1963, looking north northeast (30°). The plaque at the base of the flagpole commemorates the first firing of a liquid-fueled rocket engine at Test Stand "A" in 1945. - Jet Propulsion Laboratory Edwards Facility, Administration & Shops Building, Edwards Air Force Base, Boron, Kern County, CA
3. Interior. Looking from balance room to the front entrance. ...
3. Interior. Looking from balance room to the front entrance. Chemicals related to Edison's experiments on the extraction of latex for rubber from the goldenrod plant. Room is set up based on reconstruction research done in 1972. - Thomas A. Edison Laboratories, Building No. 2, West Orange, Essex County, NJ
LOFT. Contextual view of personnel entrance. Camera facing north. Hangar ...
LOFT. Contextual view of personnel entrance. Camera facing north. Hangar (TAN-629) at far left. Shielded control room (TAN-629) to left, containment building (TAN-650) to right. Date: May 2004. INEEL negative no. HD-39-19-2 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID
ENTRANCE TO GOLD AREA SECURITY ROOM IN BASEMENT, LOCATED IN BOTTOM OF ORIGINAL WET-BUCKET ELEVATOR SHAFT, ADJACENT TO DIESTER TABLE ROOM. NOTE BOARD WITH INDIVIDUAL TAGS FOR GOLD AREA EMPLOYEES. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO
Exterior oblique view of trash chute, balconies, and unit entrances ...
Exterior oblique view of trash chute, balconies, and unit entrances on west side of Building 10, from courtyard, looking southeast - North Beach Place, 501 Bay Street, 600 Francisco Street, 501 Bay Street, 600 Francisco Street, San Francisco, San Francisco County, CA
VIEW OF ENTRANCE SIDE OF HOUSE, TAKEN FROM NEIGHBORING CARPORT AREA. WITH NEIGHBOR?S TRASH ENCLOSURE IN FOREGROUND. VIEW FACING WEST - CAMP H.M. SMITH AND NAVY PUBLIC WORKS CENTER MANANA TITLE VII (CAPEHART) HOUSING, THREE-BEDROOM SINGLE-FAMILY TYPES 8 AND 11, Birch Circle, Elm Drive, Elm Circle, and Date Drive, Pearl City, Honolulu County, HI
View of Water Storage Tank off entrance tunnel. Tunnel at ...
View of Water Storage Tank off entrance tunnel. Tunnel at left of image to Launch Silos - Titan One Missile Complex 2A, .3 miles west of 129 Road and 1.5 miles north of County Line Road, Aurora, Adams County, CO
12. HISTORICAL VIEW OF FRONT ENTRANCE, BEFORE ADDITION OF SHELTERED PORCH, SOUTH ELEVATION, 1907. Photocopied from Henry Pleasants's book, History of Old St. David's Church, published in 1915 by John C. Winston Co. - St. David's Church (Episcopal), Valley Forge Road (Newtown Township), Wayne, Delaware County, PA
Preliminary Development of the Kindergarten Student Entrance Profile
The transition into kindergarten is important because it sets the foundation for future academic achievement. Identifying a child's readiness at school entry and intervening appropriately facilitates positive academic outcomes. The Kindergarten Student Entrance Profile (KSEP) is a school district developed universal screening measure used to…
Lilles, Elena; Furlong, Michael; Quirk, Matthew; Felix, Erika; Dominguez, Karin; Anderson, Mona
Entrance Channel Independence in the Decay of 215Fr* Nucleus
The fusion-fission excitation functions for the decay of compound nucleus 215Fr*, formed in 11B+204Pb and 18O+197Au reaction channels, are studied on the Dynamical Cluster-decay Model (DCM), showing entrance channel independence, in agreement with experiments, not invoking any quasi-fission (qf) process in either of the two channels.
Sharma, Manoj K.; Sawhney, Gudveen; Kanwar, Shefali; Gupta, Raj K.
Detail view of portal and storefront entrance at First Street ...
Detail view of portal and storefront entrance at First Street facade. Note flush recessed panels above transom lights; a historic photograph portrays elaborate detail in these exterior panels. Beginning on inscription "Post Office Arcade" appears at right; this panel is covered by a sign reading "Collier Arcade" on the Broadway facade - Post Office Arcade, 2118 First Street, Fort Myers, Lee County, FL
Are budburst dates, dormancy and cold acclimation in walnut trees (Juglans regia L.) under mainly genotypic or environmental control?
As observed for most stresses, tree frost resistance can be split into two main processes: avoidance and tolerance. Avoidance of freezing is achieved by introducing species only in the climatic context in which the probability of freezing events is very low for the sensitive stages of buds or stems; i.e., when good synchronism exists between the annual cycle and the critical climatic periods. Buds become able to grow only after chilling requirements have been satisfied (endodormancy released) during winter; they subsequently break after heat requirements have been completed (end of ecodormancy) in early spring. Actually, this period is often subject to more or less severe freezing events. Trees are also able to adjust their freezing tolerance by increasing their capacity of extracellular freezing and decreasing the possibility of intracellular freezing through the process of frost acclimation. Both freezing resistance processes (avoidance and tolerance) are environmentally driven (by photoperiod and temperature), but there are also genotypic effects among species or cultivars. Here, we evaluated the degree to which differences in dormancy release and frost acclimation were related to environmental and genetic influences by comparing trees growing in common garden conditions. This investigation was carried out for two winters in lowland and mountain locations on different walnut genotypes differing significantly for budburst dates. Chilling requirement for endodormancy release and heat requirement during ecodormancy were evaluated in all situations. In addition, frost acclimation was assessed by the electrolyte leakage method on stems from the same trees before leaf fall through budburst. No significant differences were observed in chilling requirements among genotypes. Moreover, frost acclimation dynamics were similar between genotypes or locations when expressed depending on chilling units accumulated since 15 September as a time basis instead of Julian day. The only exception was for maximal frost hardiness observed during winter with the timber-oriented being significantly more resistant than fruit-oriented genotypes. Heat requirement was significantly different among genotypes. Thus, growth was significantly faster in fruit-oriented than in wood-oriented genotypes. Furthermore, among wood-oriented genotypes, differences in growth rate were observed only at cold temperatures. Frost acclimation changes differed significantly between fruit- and wood- walnuts from January through budburst. In conclusion, from September through January, the acclimation dynamic was driven mainly by environmental factors whereas from January through budburst a significant genotype effect was identified in both frost tolerance and avoidance processes. PMID:21805380
Charrier, Guillaume; Bonhomme, Marc; Lacointe, André; Améglio, Thierry
A cell cycle checkpoint monitors cell morphogenesis in budding yeast
Checkpoint controls are regulatory pathways that inhibit cell cycle progression in cells that have not faithfully completed a prior step in the cell cycle. In the budding yeast Saccharomyces cerevisiae, DNA replication and spindle assembly are monitored by checkpoint controls that prevent nuclear division in cells that have failed to complete these processes. During the normal cell cycle, bud formation
Daniel J. Lew; Steven I. Reed
Buds on Actinidia arguta shoots do contain axillary meristems
First?order axillary buds from Actinidia arguta (Siebold et Zucc.) Planch, ex Miq. shoots were shown to develop second?order axillary structures in the first growing season of their development. This is contrary to what has been reported earlier. More importantly, the now revised description of A. arguta bud development does not support the hypothesis that flower evocation in kiwifruit (Actinidia deliciosa
E. F. Walton
Inheritance of seed dormancy in Tibetan semi-wild wheat accession Q1028.
Tibetan semi-wild wheat (Triticum aestivum ssp. tibetanum Shao) is one of the Chinese endemic hexaploid wheat genetic resources, distributed only in the Qinghai-Xizang Plateau of China. It has special characters, such as a hulled glume and spike disarticulation. However, seed dormancy, another important character for wheat resistance to pre-harvest sprouting, was rarely reported. Seed dormancy of more than 10 Tibetan semi-wild wheat accessions was evaluated, and their germinations were 0% or near 0% with both treatments of threshed seeds and intact spikes at hard dough stage. Tibetan semi-wild wheat accession Q1028 was investigated for its seed dormant characters by testing the seed germination percentages of intact spikes, seeds with bract powder, normal seeds, seeds with pierced coat, and sectioned embryos. It was observed that embryo dormancy of Q1028 accounted for its seed dormancy. Using threshed seeds and intact spikes at hard dough stage, the inheritance of seed dormancy was carried out using the F1, F2, F3 and F2BC1 populations of the cross between Q1028 and a wheat line 88-1643, susceptible to preharvest sprouting. The germinations of seeds and intact spikes in F1 plants were 1.0% and 0.9%, respectively. It indicated that seed dormancy of Q1028 was inherited as a dominant trait. From the genetic analysis of the F2, F3 and F2BC1 populations it was found that the strong seed dormancy of Q1028 was controlled by two dominant genes. PMID:15876680
Lan, Xiu-Jin; Wei, Yu-Ming; Liu, Deng-Cai; Yan, Ze-Hong; Zheng, You-Liang
Water deficit and induction of summer dormancy in perennial Mediterranean grasses
Background and Aims Summer dormancy is a trait conferring superior drought survival in Mediterranean perennial grasses. As the respective roles of environmental factors and water deficit on induction of summer dormancy are unclear, the effect of intense drought were tested under contrasting day lengths in a range of forage and native grasses. Methods Plants of Poa bulbosa, Dactylis glomerata 'Kasbah' and Lolium arundinaceum 'Flecha' were grown in pots (a) from winter to summer in a glasshouse and subjected to either an early or a late-spring drought period followed by a summer water deficit and (b) in controlled conditions, with long days (LD, 16 h) or short days (SD, 9 h) and either full irrigation or water deficit followed by rehydration. Leaf elongation, senescence of aerial tissues and dehydration of basal tissues were measured to assess dormancy. Endogenous abscisic acid (ABA) in basal tissues was determined by monoclonal immunoassay analysis. Key Results Even under irrigation, cessation of leaf elongation, senescence of lamina and relative dehydration of basal tissues were triggered only by a day length longer than 13 h 30 min (late spring and LD) in plants of Poa bulbosa and Dactylis glomerata 'Kasbah' which exhibit complete dormancy. Plants of Lolium arundinaceum 'Flecha' maintained leaf growth under irrigation irrespective of the day length since its dormancy is incomplete. ABA concentrations were not higher during late-spring drought than early, and could not be associated with spring dormancy induction. In summer, ABA concentration in bulbs of the desiccation-tolerant Poa were greater than in basal tissues of other species. Conclusions The results of both experiments tend to invalidate the hypothesis that water deficit has a role in early summer-dormancy induction in the range of tested grasses. However, a late-spring drought tends to increase plant senescence and ABA accumulation in basal tissues of forage grasses which could enhance summer drought survival.
Volaire, Florence; Seddaiu, Giovanna; Ledda, Luigi; Lelievre, Francois
Cytokinins in Vegetative and Reproductive Buds of Pseudotsuga menziesii1
Immunoaffinity techniques using columns of immobilized antibodies raised against zeatin riboside and isopentenyladenosine were found to be effective in isolating cytoklnins from vegetative, female, and male buds of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco). The purified cytokinins were separated by reverse phase high performance liquid chromatography and analyzed by radioimmunoassay. Confirmation of cytokinin identities was by gas chromatography-mass spectrometry. Immediately prior to bud burst, all bud types contained three major cytokinins: isopentenyladenosine, zeatin riboside, and a hexose conjugate of zeatin riboside (not zeatin riboside O-glucoside). Zeatin-type cytokinins were present in relatively high concentration in vegetative and female buds. In male buds, however, relatively high levels of isopentenyladenosine were found together with low levels of zeatin-type cytokinins. Images Figure 4
Morris, John W.; Doumas, Patrick; Morris, Roy O.; Zaerr, Joe B.
Cholinesterase inhibitors from Cleistocalyx operculatus buds.
Five flavonoids, myricetin-3'-methylether 3-O-?-D: -galactopyranoside (1), myricetin-3',5'-dimethylether 3-O-?-D: -galactopyranoside (2), quercetin (3), kaempferol (4), and tamarixetin (5) were isolated from the buds of Cleistocalyx operculatus (Myrtaceae). The chemical structures of these compounds were determined on the basis of spectroscopic analyses, including 2D NMR. Their anti-Alzheimer effects were evaluated via acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity assays. All five compounds 1-5 showed potential inhibitory activities against AChE with IC(50) values of 19.9, 37.8, 25.9, 30.4 and 22.3 ?M, respectively, while compounds 1, 3, 4 and 5 also possessed BChE inhibitory activity with IC(50) values of 152.5, 177.8, 62.5, and 160.6 ?M, respectively. PMID:21052942
Min, Byung Sun; Cuong, To Dao; Lee, Joo-Sang; Shin, Beom-Soo; Woo, Mi Hee; Hung, Tran Manh
Entrance dose measurement: a simple and reliable technique.
Verification of tumor dose for patients undergoing external beam radiotherapy is an important part of quality assurance programs in radiation oncology. Among the various methods available, entrance dose in vivo is one reliable method used to verify the tumor dose delivered to a patient. In this work, entrance dose measurements using LiF:Mg;Ti and LiF:Mg;Cu;P thermoluminescent dosimeters (TLDs) without buildup cap was carried out. The TLDs were calibrated at the surface of a water equivalent phantom against the maximum dose, using 6- and 10-MV photon and 9-MeV electron beams. The calibration geometry was such that the TLDs were placed on the surface of the "solid-water" phantom and a calibrated ionization chamber was positioned inside the phantom at calibration depth. The calibrated TLDs were then utilized to measure the entrance dose during the treatment of actual patients. Measurements were also carried out in the same phantom simultaneously to check the stability of the system. The dose measured in the phantom using the TLDs calibrated for entrance dose to 6-and 10-MV photon beams was found to be close to the dose determined by the treatment planning system (TPS) with discrepancies of not more than 4.1% (mean 1.3%). Consequently, the measured entrance dose during dose delivery to the actual patients with a prescribed geometry was found to be compatible with a maximum discrepancy of 5.7% (mean 2.2%) when comparison was made with the dose determined by the TPS. Likewise, the measured entrance dose for electron beams in the phantom and in actual patients using the calibrated TLDs were also found to be close, with maximum discrepancies of 3.2% (mean 2.0%) and 4.8% (mean 2.3%), respectively. Careful implementation of this technique provides vital information with an ability to confidently accept treatment algorithms derived by the TPS or to re-evaluate the parameters when necessary. PMID:12804703
Banjade, D P; Raj, T Aloysius; Ng, B S; Xavier, S; Tajuddin, A A; Shukri, A
Dual action of respiratory inhibitors: inhibition of germination and prevention of dormancy induction in lettuce seeds.
;Grand Rapids' lettuce Lactuca sativa L. seeds germinate readily at 15 degrees C but poorly at 25 degrees C in darkness. When held in dark at 25 degrees C for an extended period, the ungerminated seeds become dormant as shown by their inability to germinate or transfer to 15 degrees C in darkness. Induction of dormancy at 25 degrees C was prevented by exposure to CN(-), azide, salicylhydroxamic acid (SHAM), dinitrophenol, and pure N(2) as determined by subsequent germination at 15 degrees C on removal of inhibitors. The effectiveness of inhibitors to break dormancy declined as dormancy intensified. At relatively low levels, CN(-), SHAM, and azide promoted dark germination at 25 degrees C while at high levels they were inhibitory. Uptake of O(2) by seeds held at 25 degrees C for 4 days in 1.0 millimolar KCN was inhibited by 67% but was promoted 61% when KCN was removed. Correspondingly greater inhibition (79%) and promotion (148%) occurred when 1.0 millimolar SHAM was added to KCN solution. When applied alone, SHAM had little effect on O(2) uptake. These data indicate that Cyt pathway of respiration plays a dominant role in the control of both dormancy induction and germination of lettuce seeds, and ;alternative pathway' is effectively engaged in presence of CN(-). The channeling of respiratory energy use for processes governing germination or dormancy is subject to control by physical and chemical factors.A scheme is proposed that illustrates compensatory use of energy for processes controlling dormancy induction and germination. A block of germination, e.g. by low water potential polyethylene glycol solution or a supraoptimal temperature spares energy to be utilized for dormancy induction while a block of dormancy induction by low levels of CN(-) (similar to GA and light effects) drives germination. Blocking both processes by inhibitors (e.g. CN(-), CN(-) + SHAM) presumably leads to accumulation of ;reducing power' with consequent improvement in O(2) uptake and oxidation rates of processes controlling germination or dormancy induction upon removal of the inhibitors. PMID:16664144
Khan, A A; Zeng, G W
33 CFR 334.390 - Atlantic Ocean south of entrance to Chesapeake Bay; firing range.
...Waters 3 2013-07-01 2013-07-01 false Atlantic Ocean south of entrance to Chesapeake Bay; firing range...ZONE AND RESTRICTED AREA REGULATIONS § 334.390 Atlantic Ocean south of entrance to Chesapeake Bay; firing...
Smouldering Malignant Melanoma and Metastatic Dormancy: An Update and Review
The fund of knowledge regarding the versatility of presentation of MM metastases is still quite incomplete. The recent literature pertaining to the current understanding of the mechanisms underlying two special features of MM metastasis is reviewed. On the one hand, a long disease-free interval (MM dormancy) may occur before the surge of overt metastases. On the other hand, the so-called MM smouldering phenomenon refers to the condition where regional metastases wax and wane for long periods of time on restricted skin regions. It is important to emphasize that local micrometastases often predict sentinel lymph node involvement but may not reflect progression of the primary MM to full-blown visceral metastatic competence. It is likely that a combination of factors impacts the versatile MM metastasic progression. Among the main factors, one has to mention the phenotypic heterogeneity and variability in the phenotype of MM cells, the presence of MM stem cells and MM cells engaged in an amplification proliferation pool, as well as the host immune response, and possibly the induction of a particular stromal structure and vascularity.
Pierard, Gerald E.; Pierard-Franchimont, Claudine; Reginster, Marie-Annick; Quatresooz, Pascale
Dormancy Genes From Weedy Rice Respond Divergently to Seed Development Environments
Genes interacting with seed developmental environments control primary dormancy. To understand how a multigenic system evolved to adapt to the changing environments in weedy rice, we evaluated genetic components of three dormancy QTL in a synchronized nondormant genetic background. Two genetically identical populations segregating for qSD1, qSD7-1, and qSD12 were grown under greenhouse and natural conditions differing in temperature, relative humidity, and light intensity during seed development. Low temperatures tended to enhance dormancy in both conditions. However, genotypes responded to the environments divergently so that two populations displayed similar distributions for germination. Additive and/or dominance effects of the three loci explained ?90% of genetic variances and their epistases accounted for the remainder in each environment. The qSD1 and qSD7-1 main effects were increased, while the qSD12 additive effect was decreased by relatively low temperatures. Both gene main and epistatic effects were involved in G × E interactions, which in magnitude were greater than environmental main effect. The divergent responses of dormancy genes observed in this simple multigenic system presumably have selective advantages in natural populations adapted to changing environments and hence represent a genetic mechanism stabilizing the dormancy level of weedy rice ripened in different seasons or temperature regimes.
Molecular cloning of Sdr4, a regulator involved in seed dormancy and domestication of rice
Seed dormancy provides a strategy for flowering plants to survive adverse natural conditions. It is also an important agronomic trait affecting grain yield, quality, and processing performance. We cloned a rice quantitative trait locus, Sdr4, which contributes substantially to differences in seed dormancy between japonica (Nipponbare) and indica (Kasalath) cultivars. Sdr4 expression is positively regulated by OsVP1, a global regulator of seed maturation, and in turn positively regulates potential regulators of seed dormancy and represses the expression of postgerminative genes, suggesting that Sdr4 acts as an intermediate regulator of dormancy in the seed maturation program. Japonica cultivars have only the Nipponbare allele (Sdr4-n), which endows reduced dormancy, whereas both the Kasalath allele (Srd4-k) and Sdr4-n are widely distributed in the indica group, indicating prevalent introgression. Srd4-k also is found in the wild ancestor Oryza rufipogon, whereas Sdr4-n appears to have been produced through at least two mutation events from the closest O. rufipogon allele among the accessions examined. These results are discussed with respect to possible selection of the allele during the domestication process.
Sugimoto, Kazuhiko; Takeuchi, Yoshinobu; Ebana, Kaworu; Miyao, Akio; Hirochika, Hirohiko; Hara, Naho; Ishiyama, Kanako; Kobayashi, Masatomo; Ban, Yoshinori; Hattori, Tsukaho; Yano, Masahiro
Seed dormancy and responses of caryopses, embryos, and calli to abscisic Acid in wheat.
Preharvest sprouting of wheat (Triticum aestivum L.) is associated with inadequate seed dormancy. Although abscisic acid (ABA) has often been suggested to play a central role in developing seed, its involvement in dormancy of mature seed lacks firm experimental evidence and endogenous ABA levels are not well correlated with germinability. We examined genotypic and temporal variation in wheat seed and embryo germination responses to ABA and determined whether differential sensitivity of embryos to ABA extended to growth of embryo-derived calli. Germination of Parker 76 caryopses, which have little dormancy at maturity, was only slightly inhibited by ABA, whereas germination of Clark's Cream, a highly dormant genotype, was greatly inhibited. Responsiveness of caryopses to ABA and dormancy of seeds decreased concurrently during afterripening. Germination of embryos excised from dormant and nondormant seeds was more responsive to ABA but otherwise was similar to that of caryopses, indicating that differential response to ABA occurs in the embryo. Growth of calli derived from immature embryos of two sprouting-susceptible wheat genotypes exceeded growth of calli from Clark's Cream, but no distinct differences in response to ABA among the genotypes were apparent. We concluded that the action of ABA is similar in developing and mature seeds, that genotypic and temporal variation in embryo responsiveness to endogenous ABA may be involved in dormancy, and that ABA probably acts in concert with other endogenous constituents. PMID:16666821
Morris, C F; Moffatt, J M; Sears, R G; Paulsen, G M
Influence of the Testa on Seed Dormancy, Germination, and Longevity in Arabidopsis1
The testa of higher plant seeds protects the embryo against adverse environmental conditions. Its role is assumed mainly by controlling germination through dormancy imposition and by limiting the detrimental activity of physical and biological agents during seed storage. To analyze the function of the testa in the model plant Arabidopsis, we compared mutants affected in testa pigmentation and/or structure for dormancy, germination, and storability. The seeds of most mutants exhibited reduced dormancy. Moreover, unlike wild-type testas, mutant testas were permeable to tetrazolium salts. These altered dormancy and tetrazolium uptake properties were related to defects in the pigmentation of the endothelium and its neighboring crushed parenchymatic layers, as determined by vanillin staining and microscopic observations. Structural aberrations such as missing layers or a modified epidermal layer in specific mutants also affected dormancy levels and permeability to tetrazolium. Both structural and pigmentation mutants deteriorated faster than the wild types during natural aging at room temperature, with structural mutants being the most strongly affected.
Debeaujon, Isabelle; Leon-Kloosterziel, Karen M.; Koornneef, Maarten
ROS production and protein oxidation as a novel mechanism for seed dormancy alleviation.
At harvest, sunflower (Helianthus annuus L.) seeds are dormant and unable to germinate at temperatures below 15 degrees C. Seed storage in the dry state, known as after-ripening, is associated with an alleviation of embryonic dormancy allowing subsequent germination at suboptimal temperatures. To identify the process by which dormancy is broken during after-ripening, we focused on the role of reactive oxygen species (ROS) in this phenomenon. After-ripening entailed a progressive accumulation of ROS, namely superoxide anions and hydrogen peroxide, in cells of embryonic axes. This accumulation, which was investigated at the cellular level by electron microscopy, occurred concomitantly with lipid peroxidation and oxidation (carbonylation) of specific embryo proteins. Incubation of dormant seeds for 3 h in the presence of hydrogen cyanide (a compound that breaks dormancy) or methylviologen (a ROS-generating compound) also released dormancy and caused the oxidation of a specific set of embryo proteins. From these observations, we propose a novel mechanism for seed dormancy alleviation. This mechanism involves ROS production and targeted changes in protein carbonylation patterns. PMID:17376157
Oracz, Krystyna; El-Maarouf Bouteau, Hayat; Farrant, Jill M; Cooper, Keren; Belghazi, Maya; Job, Claudette; Job, Dominique; Corbineau, Françoise; Bailly, Christophe
6. HOUSE REAR EXTERIOR SHOWING UTILITY PORCH AND REAR ENTRANCE TO DINNING/KITCHEN AREA AT PHOTO CENTER. SMALL RECTANGULAR STRUCTURE ATTACHED TO SIDE OF HOUSE AT PHOTO RIGHT CENTER BELOW SMALL, DOUBLEHUNG, WOOD-FRAME WINDOW IS THE HOT WATER HEATER CABINET. VIEW TO SOUTHEAST. - Big Creek Hydroelectric System, Big Creek Town, Operator House, Orchard Avenue south of Huntington Lake Road, Big Creek, Fresno County, CA
Proteome analysis of Norway maple (Acer platanoides L.) seeds dormancy breaking and germination: influence of abscisic and gibberellic acids
BACKGROUND: Seed dormancy is controlled by the physiological or structural properties of a seed and the external conditions. It is induced as part of the genetic program of seed development and maturation. Seeds with deep physiological embryo dormancy can be stimulated to germinate by a variety of treatments including cold stratification. Hormonal imbalance between germination inhibitors (e.g. abscisic acid) and
Tomasz A Paw?owski
Sodium nitroprusside, cyanide, nitrite, and nitrate break Arabidopsis seed dormancy in a nitric oxide-dependent manner
The seeds of many plant species are dormant at maturity and dormancy loss is a prerequisite for germination. Numerous environmental and chemical treatments are known to lessen or remove seed dormancy, but the biochemical changes that occur during this change of state are poorly understood. Several lines of research have implicated nitric oxide (NO) as a participant in this process.
Paul C. Bethke; Igor G. L. Libourel; Vilem Reinöhl; Russell L. Jones
Response to abscisic acid application and hormone profiles in spring Brassica napus seed in relation to secondary dormancy
The plant hormone abscisic acid (ABA) has been implicated in the inception and maintenance of seed dor- mancy, while gibberellins promote dormancy breakage and germination in some species. We investigated whether osmotic stress induced secondary dormancy in Brassica napus L. is associated with changes in ABA sensitivity and metabolism, as well as changes in gibberellin levels. Seeds of two genotypes,
Robert H. Gulden; Sheila Chiwocha; Suzanne Abrams; Ian McGregor; Allison Kermode; Steven Shirtliffe
Mimicking a Semi-arid Tropical Environment Achieves Dormancy Alleviation for Seeds of Australian Native Goodeniaceae and Asteraceae
†Background and Aims Seed physiological dormancy (PD) limits the use and conservation of some of Queensland's (Qld) native forb species. It was hypothesised that optimum dormancy-alleviating treatments would reflect environ- mental conditions that seeds experience in situ, and this premise was tested for PD seeds of four species native to south-west Qld. †Methods High temperatures and increased rainfall during summer
Seed dormancy and germination: the role of abscisic acid and gibberellins and the importance of hormone mutants
Over the past decades many studies have aimed at elucidating the regulation of seed dormancy and germination. Many hypotheses have been proposed and rejected but the regulatory principle behind changes in dormancy and induction of germination is still a 'black' box. The majority of proposed mechanisms have a role for certain plant hormones in common. Abscisic acid and the gibberellins
H. W. M. Hilhorst; C. M. Karssen
A luciferase-based budding assay for Ebola virus.
The VP40 matrix protein of Ebola virus (EBOV) is capable of budding from mammalian cells as a virus-like particle (VLP) and is the major protein involved in virus egress. A functional budding assay has been developed based upon this characteristic of VP40 to assess the contributions of VP40 sequences as well as host proteins to the budding process. This well-defined assay has been modified for potential use in a high-throughput format in which the detection and quantification of firefly luciferase protein in VLPs represents a direct measure of VP40 budding efficiency. Luciferase was found to be incorporated into budding VP40 VLPs. Furthermore, co-expression of EBOV glycoprotein (GP) enhances release of VLPs containing VP40 and luciferase. In contrast, when luciferase is co-expressed with a budding deficient mutant of VP40, luciferase levels in the VLP fraction decrease significantly. This assay represents a promising high-throughput approach to identify inhibitors of EBOV budding. PMID:16837071
McCarthy, Sarah E; Licata, Jillian M; Harty, Ronald N
Cell cycle regulation during development and dormancy in embryos of the annual killifish Austrofundulus limnaeus
Embryos of the annual killifish Austrofundulus limnaeus can enter into a state of metabolic dormancy, termed diapause, as a normal part of their development. In addition, these embryos can also survive for prolonged sojourns in the complete absence of oxygen. Dormant embryos support their metabolism using anaerobic metabolic pathways, regardless of oxygen availability. Dormancy in diapause is associated with high ATP and a positive cellular energy status, while anoxia causes a severe reduction in ATP content and large reductions in adenylate energy charge and ATP/ADP ratios. Most cells are arrested in the G1/G0 phase of the cell cycle during diapause and in response to oxygen deprivation. In this paper, we review what is known about the physiological and biochemical mechanisms that support metabolic dormancy in this species. We also highlight the great potential that this model holds for identifying novel therapies for human diseases such as heart attack, stroke and cancer.
Podrabsky, Jason E.; Culpepper, Kristin M.
LEC1, FUS3, ABI3 and Em expression reveals no correlation with dormancy in Arabidopsis.
Dormant Arabidopsis seeds require stratification and light for germination. To study gene expression during establishment, maintenance and release of dormancy, various Arabidopsis ecotypes that are different in their degree of dormancy were investigated; three nsm mutants that lack the stratification-dependency, and the precocious germination and reduced dormancy of the abi3-1 mutant (insensitive to ABA). Genes examined by mRNA abundance include LEC1, FUS3 and ABI3, transcription factors that are major regulators of embryo development and, at least indirectly, play some role in the control of dormancy. Moreover, the late embryogenesis marker genes, AtEm1 and AtEm6, were examined in relation to the state of dormancy. The expression of LEC1, FUS3 and ABI3 mRNA is only marginally different during seed development in various strong or moderate dormancy wild types, nsm mutants and abi3-1. Therefore, it is unlikely that these transcription factors directly control the establishment of dormancy in Arabidopsis. Sole and various combina tions of light, temperature, and after-ripening regimes that alter germination behaviour were examined to determine if the expression of ABI3, AtEm1 and AtEm6 mRNAs were correlated with dormancy-breaking processes. ABI3 expression is influenced by cold and light, in a similar way in both dormant and non-dormant wild-type seeds. ABI3 transcript abundance in the nsm1 and nsm2 mutants is higher and in the nsm5-1 mutant is marginally lower than in wild-type seeds, but changes due to temperature and light factors are very similar to those that occur in wild-type seeds. The abundances of AtEm1 and AtEm6 mRNAs are equally affected by imbibition and cold temperature in mature and after-ripened seeds. The LEA transcript abundances for AtEm1 and AtEm6 are reduced in nsm mutants in a common, ABI3-independent pathway. PMID:14676287
Baumbusch, Lars O; Hughes, D Wayne; Galau, Glenn A; Jakobsen, Kjetill S
Control of bud activation by an auxin transport switch
In many plant species only a small proportion of buds yield branches. Both the timing and extent of bud activation are tightly regulated to produce specific branching architectures. For example, the primary shoot apex can inhibit the activation of lateral buds. This process is termed apical dominance and is dependent on the plant hormone auxin moving down the main stem in the polar auxin transport stream. We use a computational model and mathematical analysis to show that apical dominance can be explained in terms of an auxin transport switch established by the temporal precedence between competing auxin sources. Our model suggests a mechanistic basis for the indirect action of auxin in bud inhibition and captures the effects of diverse genetic and physiological manipulations. In particular, the model explains the surprising observation that highly branched Arabidopsis phenotypes can exhibit either high or low auxin transport.
Prusinkiewicz, Przemyslaw; Crawford, Scott; Smith, Richard S.; Ljung, Karin; Bennett, Tom; Ongaro, Veronica; Leyser, Ottoline
Tolerance of budding yeast Saccharomyces cerevisiae to ultra high pressure
Our studies on the tolerance of plants and animals against very high pressure of several GPa have been extended to a smaller sized fungus, the budding yeast Saccharomyces cerevisiae. Several pieces of budding yeast (dry yeast) were sealed in a small teflon capsule with a liquid pressure medium fluorinate, and exposed to 7.5 GPa by using a cubic anvil press. The pressure was kept constant for various duration of time from 2 to 24 h. After the pressure was released, the specimens were brought out from the teflon capsule, and they were cultivated on a potato dextrose agar. It was found that the budding yeast exposed to 7.5 GPa for up to 6 h showed multiplication. However, those exposed to 7.5 GPa for longer than 12 h were found dead. The high pressure tolerance of budding yeast is a little weaker than that of tardigrades.
Shibata, M.; Torigoe, M.; Matsumoto, Y.; Yamamoto, M.; Takizawa, N.; Hada, Y.; Mori, Y.; Takarabe, K.; Ono, F.
Control of bud activation by an auxin transport switch.
In many plant species only a small proportion of buds yield branches. Both the timing and extent of bud activation are tightly regulated to produce specific branching architectures. For example, the primary shoot apex can inhibit the activation of lateral buds. This process is termed apical dominance and is dependent on the plant hormone auxin moving down the main stem in the polar auxin transport stream. We use a computational model and mathematical analysis to show that apical dominance can be explained in terms of an auxin transport switch established by the temporal precedence between competing auxin sources. Our model suggests a mechanistic basis for the indirect action of auxin in bud inhibition and captures the effects of diverse genetic and physiological manipulations. In particular, the model explains the surprising observation that highly branched Arabidopsis phenotypes can exhibit either high or low auxin transport. PMID:19805140
Prusinkiewicz, Przemyslaw; Crawford, Scott; Smith, Richard S; Ljung, Karin; Bennett, Tom; Ongaro, Veronica; Leyser, Ottoline
Functional Cell Types in Taste Buds Have Distinct Longevities
Taste buds are clusters of polarized sensory cells embedded in stratified oral epithelium. In adult mammals, taste buds turn over continuously and are replenished through the birth of new cells in the basal layer of the surrounding non-sensory epithelium. The half-life of cells in mammalian taste buds has been estimated as 8–12 days on average. Yet, earlier studies did not address whether the now well-defined functional taste bud cell types all exhibit the same lifetime. We employed a recently developed thymidine analog, 5-ethynil-2?-deoxyuridine (EdU) to re-evaluate the incorporation of newly born cells into circumvallate taste buds of adult mice. By combining EdU-labeling with immunostaining for selected markers, we tracked the differentiation and lifespan of the constituent cell types of taste buds. EdU was primarily incorporated into basal extragemmal cells, the principal source for replenishing taste bud cells. Undifferentiated EdU-labeled cells began migrating into circumvallate taste buds within 1 day of their birth. Type II (Receptor) taste cells began to differentiate from EdU-labeled precursors beginning 2 days after birth and then were eliminated with a half-life of 8 days. Type III (Presynaptic) taste cells began differentiating after a delay of 3 days after EdU-labeling, and they survived much longer, with a half-life of 22 days. We also scored taste bud cells that belong to neither Type II nor Type III, a heterogeneous group that includes mostly Type I cells, and also undifferentiated or immature cells. A non-linear decay fit described these cells as two sub-populations with half-lives of 8 and 24 days respectively. Our data suggest that many post-mitotic cells may remain quiescent within taste buds before differentiating into mature taste cells. A small number of slow-cycling cells may also exist within the perimeter of the taste bud. Based on their incidence, we hypothesize that these may be progenitors for Type III cells.
Perea-Martinez, Isabel; Nagai, Takatoshi; Chaudhari, Nirupa
Mutational and hyperexpression-induced disruption of bipolar budding in yeast
Analysis of bud-site selection in the yeast Saccharomyces cerevisiae has helped to identify many genes that are generally important for eukaryotic cell polarization. Colony morphology screens were used to identify factors relevant to the process of bipolar budding in yeast. Mutants defective in bipolar budding were identified by virtue of their inability to grow as pseudohyphae in a haploid bud3
Toby Freedman; Alexandra Porter; Brian Haarer
Budding and fruitfulness of seedless grape in the Săo Francisco River Valley, northeast Brazil
th 2002, and Apr 8 th to 12 th 2002. The bud burst percentage was calculated by the ratio number of pushed buds and the total number of buds. The fertility index was obtained by dividing the total number of bunches by the total number of buds per plant. The results were statistically analyzed by the SAS computer program, and
Patrícia Coelho de S. Leăo; Emanuel E. G da Silva
Bioengineered Teeth from Cultured Rat Tooth Bud Cells
The recent bioengineering of complex tooth structures from pig tooth bud tissues suggests the potential for the regeneration of mammalian dental tissues. We have improved tooth bioengineering methods by comparing the utility of cultured rat tooth bud cells obtained from three-to seven-day post-natal (dpn) rats for tooth-tissue-engineering applications. Cell-seeded biodegradable scaffolds were grown in the omenta of adult rat hosts
M. T. Duailibi; S. E. Duailibi; C. S. Young; J. D. Bartlett; J. P. Vacanti; P. C. Yelick
A QTL located on chromosome 4A associated with dormancy in white- and red-grained wheats of diverse origin.
Improved resistance to preharvest sprouting in modern bread wheat (Triticum aestivum. L.) can be achieved via the introgression of grain dormancy and would reduce both the incidence and severity of damage due to unfavourable weather at harvest. The dormancy phenotype is strongly influenced by environmental factors making selection difficult and time consuming and this trait an obvious candidate for marker assisted selection. A highly significant Quantitative Trait Locus (QTL) associated with grain dormancy and located on chromosome 4A was identified in three bread wheat genotypes, two white- and one red-grained, of diverse origin. Flanking SSR markers on either side of the putative dormancy gene were identified and validated in an additional population involving one of the dormant genotypes. Genotypes containing the 4A QTL varied in dormancy phenotype from dormant to intermediate dormant. Based on a comparison between dormant red- and white-grained genotypes, together with a white-grained mutant derived from the red-grained genotype, it is concluded that the 4A QTL is a critical component of dormancy; associated with at least an intermediate dormancy on its own and a dormant phenotype when combined with the R gene in the red-grained genotype and as yet unidentified gene(s) in the white-grained genotypes. These additional genes appeared to be different in AUS1408 and SW95-50213. PMID:16133305
Mares, D; Mrva, K; Cheong, J; Williams, K; Watson, B; Storlie, E; Sutherland, M; Zou, Y
Wet-season Dormancy Release in Seed Banks of a Tropical Leguminous Shrub is Determined by Wet Heat
• Background and Aims Hard-seeded (physical) dormancy is common among plants, yet mechanisms for dormancy release are poorly understood, especially in the tropics. The following questions are asked: (a) whether dormancy release in seed banks of the tropical shrub Parkinsonia aculeata (Caesalpiniaceae) is determined by wet heat (incubation under wet, warm to hot, conditions); and (b) whether its effect is modified by microclimate. • Methods A seed burial trial was conducted in the wet–dry tropics (northern Australia) to compare dormancy release across different habitats (open, artificial cover, ground cover and canopy cover), burial depths (0, 3 and 20?cm) and burial durations (2, 6 and 14 weeks). Results were compared with predictions using a laboratory-derived relationship between wet heat and dormancy release, and microclimate data collected during the trial. • Key Results Wet heat (defined as the soil temperature above which seeds were exposed to field capacity or higher for a cumulative total of 24?h) was 43·6?°C in the 0?cm open treatment, and decreased with increasing shade and depth to 29·5?°C at 20?cm under canopy cover. The dormancy release model showed that wet heat was a good predictor of the proportion of seeds remaining dormant. Furthermore, dormancy release was particularly sensitive to wet heat across the temperature range encountered across treatments. This resulted in a 16-fold difference in dormancy levels between open (<5?% of seeds still dormant) and covered (82?%) microhabitats. • Conclusions These results demonstrate that wet heat is the principal dormancy release mechanism for P. aculeata when conditions are hot and wet. They also highlight the potential importance of microclimate in driving the population dynamics of such species.
Eco-physiological studies on Zornia diphylla pers. with reference to adaptive seed dormancy
Summary Seeds ofZornia diphylla possess a complex type of dormancy which is of great survival value for the species. Seeds show polymorphism. The optimum temperature for germination explains the cause of its distribution in the tropics. The grazing and scraping promotes the vegetative growth.
H. P. Singh
Drought and high temperature increases preharvest sprouting tolerance in a genotype without grain dormancy
Preharvest sprouting is common in cereals, which lack grain dormancy when maturing grain is exposed to rainfall or high moisture conditions. Environmental conditions such as drought and high temperature during grain filling have a large effect on the expression of sprouting tolerance. A dormant (DM 2001) and non-dormant (Cunderdin) hard white spring wheat were exposed to drought or irrigated conditions
T. B. Biddulph; D. J. Mares; J. A. Plummer; T. L. Setter
Akt and its downstream targets play key roles in mediating dormancy in land snails
Estivation, a state of aerobic dormancy, facilitates survival during adverse environmental conditions and is characterized at the molecular level by regulatory protein phosphorylation. The Akt (protein kinase B) signaling pathway regulates diverse responses in cells and the present study analyzes its role in the estivating desert snail Otala lactea. Kinetic analysis (maximal velocity, substrate affinities) determined that Akt was activated
Christopher J. Ramnanan; Amy G. Groom; Kenneth B. Storey
8. The role of plant growth regulators in dormancy in forest trees
The role of plant growth regulators, i.e. indole-3-acetic acid, abscisic acid, gibberellins, cytokinins, and ethylene, in the initiation, maintenance, and breaking of dormancy in perennial, woody, temperate plants is reviewed. Particular topics discussed include: a) roles of individual compounds and antagonistic or synergistic effects of several growth regulators acting simultaneously; b) problems of compound isolation and identification; and c) hypotheses
Denis P. Lavender; Salim N. Silim
Breaking seed coat dormancy of Acacia nilotica seeds under simulated natural habitat conditions in Sudan
This study attempted to break the seed coat dormancy of Acacia nilotica, a riverine tree species, by simulating natural conditions. The effects of extended water soaking, soil burial and shade placement on seeds and pods were studied. Pods, clean-seeds and unclean-seeds were soaked in water for periods up to 24 weeks in two sites with or without forest soil. The
The relations between phenolic compounds and seed dormancy in Pistacia spp
SUMMARY - This investigation was carried out to study the germination percentage of seeds and relations between phenolics and seed dormancy of Pistacia spp. The seeds were collected from the trees of Pistacia atlantica, P. terebinthus and a hybrid, which has unknown parents, in Barbaros village of Çe_me region close to _zmir. They were sown in petri dishes for determining
E. Özeker
Effect of exogenous hormones and chilling on dormancy breaking of seed of Asafoetida (Ferula assafoetida L.)
Asafoetida (Ferula assafoetida L.) is a medicinal plant with a problematic seed germination. Seeds of this plant have a long dormancy. The present research was carried out to investigate whether exogenous application of the hormones Gibberellic Acid (GA3), N6-furfurylaminopurine (kinetin) and 6-benzylaminopurine (BAP), alone or in combinations and chilling (for 0 or 28 days) could be used to alleviate the
M. Otroshy; A. Zamani; M. Khodambashi; M. Ebrahimi; P. C. Struik
Seedling emergence patterns and dormancy\\/germination physiology of Primula modesta in a subalpine region
On the basis of the germination\\/dormancy responses of seeds to temperature and light, and local seed rain, we attempted to interpret the seedling emergence patterns of Primula modesta Bisset et Moore (Primulaceae) in two different types of habitats in a subalpine zone of Mt. Asama: an oligotrophic flat moor and a grassland with relatively dense herbaceous vegetation cover. The seasonal
Ayako SHIMONO; Izumi WASHITANI
Onset of Dormancy in the Copepod Calanus pacificus californicus Off Southern California.
This grant supported the Ph.D. dissertation research of Catherine L. Johnson. Dr. Johnson was awarded her Ph.D. in May 2003. The research conducted under this grant examined the onset of and emergence from dormancy of C. pacificus californicus and its dis...
D. M. Checkley
The LuxR family regulator Rv0195 modulates Mycobacterium tuberculosis dormancy and virulence.
Tuberculosis is a leading global killer that has not been effectively controlled to date. The ability of the causative agent, Mycobacterium tuberculosis, to become dormant is one of the major reasons for extended chemotherapeutic regimens and wide epidemicity. The underlying mechanisms of M. tuberculosis dormancy are not fully understood. In the present work, a LuxR family transcription factor gene, Rv0195, was deleted in the virulent M. tuberculosis strain H37Rv. Rv0195 deletion did not affect bacterial growth and long-term survival under aerobiosis but decreased cell survival and the ability to rapidly recover from dormancy in an in vitro anaerobiosis model. The deletion also reduced intracellular survivability under hypoxic and reductive stress triggered by vitamin C. Microarray hybridization analysis showed that Rv0195 affected the expression of more than 180 genes under anaerobiosis, and these genes did not overlap with the known anaerobiosis-up-regulated DosR regulon genes. Furthermore, the Rv0195 deletion diminished bacterial virulence in human macrophage-like cells and resulted in reduced bacterial survival and pathogenicity in a C57BL/6 mouse infection model. These findings offer a novel insight into the mechanisms by which M. tuberculosis adapts to and recovers from dormancy and demonstrate that the dormancy regulator Rv0195 contributes to bacterial virulence. PMID:23673208
Fang, Haihong; Yu, Dan; Hong, Yuzhi; Zhou, Xiaodan; Li, Chuanyou; Sun, Baolin
Insights into the regulation of tumor dormancy by angiogenesis in experimental tumors.
While it is well established that an angiogenic switch marks escape from tumor dormancy in xenograft models, the molecular pathways involved in the control of tumor cell proliferation or survival by angiogenesis remain substantially uncharted. We recently demonstrated that signals stemming from angiogenic endothelial cells (EC) regulate the behavior of dormant cancer cells. Specifically, we observed that the Notch ligand Dll4, induced by angiogenic factors in EC, triggers Notch3 activation in neighboring tumor cells and promotes a tumorigenic phenotype. Evidence that Notch signaling is involved in tumor dormancy was further strengthened by the observation that MKP-1 levels-a broadly expressed phosphatase-are controlled by Notch3 by regulation of protein ubiquitination and stability. Notch3 and MKP-1 levels are consistently low in dormant tumors, and this is accompanied by relatively high levels of phosphorylated p38, a canonical MKP-1 target previously associated with maintenance of tumor dormancy. These results elucidate a novel angiogenesis-driven mechanism involving the Notch and MAPK pathways that controls tumor dormancy. More in general, angiogenic EC could form part of the vascular niche, a specialized microenvironment which appears to regulate metastatic outgrowth and future studies are needed to clarify the contribution of EC in the regulation of cancer stem cell behavior in the niche.The notion that EC could communicate signals to tumor cells raises questions about the possibility of achieving tumor dormancy by counteracting angiogenesis. In experimental tumors, anti-VEGF drugs typically prune the newly formed vasculature, thus reducing microvessel density, blood flow, and perfusion. These drugs eventually increase hypoxia and cause tumor necrosis but dormancy is rarely observed. Our group recently reported that anti-VEGF therapy causes a dramatic depletion of glucose and an exhaustion of ATP levels in tumors. Moreover, we found that the central metabolic checkpoint LKB1/AMPK-a cellular sensor of ATP levels that supports cell viability in response to energy stress-is activated by anti-VEGF therapy in experimental tumors and it has a key role in induction of sustained tumor regression. These functional links between activation of the LKB1/AMPK by anti-angiogenic therapy and tumor dormancy suggest a role for metabolism in the regulation of this phenomenon. PMID:23143974
Indraccolo, Stefano
Electron Tomography Reveals the Steps in Filovirus Budding
The filoviruses, Marburg and Ebola, are non-segmented negative-strand RNA viruses causing severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. The sequence of events that leads to release of filovirus particles from cells is poorly understood. Two contrasting mechanisms have been proposed, one proceeding via a "submarine-like" budding with the helical nucleocapsid emerging parallel to the plasma membrane, and the other via perpendicular "rocket-like" protrusion. Here we have infected cells with Marburg virus under BSL-4 containment conditions, and reconstructed the sequence of steps in the budding process in three dimensions using electron tomography of plastic-embedded cells. We find that highly infectious filamentous particles are released at early stages in infection. Budding proceeds via lateral association of intracellular nucleocapsid along its whole length with the plasma membrane, followed by rapid envelopment initiated at one end of the nucleocapsid, leading to a protruding intermediate. Scission results in local membrane instability at the rear of the virus. After prolonged infection, increased vesiculation of the plasma membrane correlates with changes in shape and infectivity of released viruses. Our observations demonstrate a cellular determinant of virus shape. They reconcile the contrasting models of filovirus budding and allow us to describe the sequence of events taking place during budding and release of Marburg virus. We propose that this represents a general sequence of events also followed by other filamentous and rod-shaped viruses.
Welsch, Sonja; Kolesnikova, Larissa; Krahling, Verena; Riches, James D.; Becker, Stephan; Briggs, John A. G.
Stromal Protein Ecm1 Regulates Ureteric Bud Patterning and Branching
The interactions between the nephrogenic mesenchyme and the ureteric bud during kidney development are well documented. While recent studies have shed some light on the importance of the stroma during renal development, many of the signals generated in the stroma, the genetic pathways and interaction networks involving the stroma are yet to be identified. Our previous studies demonstrate that retinoids are crucial for branching of the ureteric bud and for patterning of the cortical stroma. In the present study we demonstrate that autocrine retinoic acid (RA) signaling in stromal cells is critical for their survival and patterning, and show that Extracellular matrix 1, Ecm1, a gene that in humans causes irritable bowel syndrome and lipoid proteinosis, is a novel RA-regulated target in the developing kidney, which is secreted from the cortical stromal cells surrounding the cap mesenchyme and ureteric bud. Our studies suggest that Ecm1 is required in the ureteric bud for regulating the distribution of Ret which is normally restricted to the tips, as inhibition of Ecm1 results in an expanded domain of Ret expression and reduced numbers of branches. We propose a model in which retinoid signaling in the stroma activates expression of Ecm1, which in turn down-regulates Ret expression in the ureteric bud cleft, where bifurcation normally occurs and normal branching progresses.
Paroly, Suneeta S.; Wang, Fengwei; Spraggon, Lee; Merregaert, Joseph; Batourina, Ekatherina; Tycko, Benjamin; Schmidt-Ott, Kai M.; Grimmond, Sean; Little, Melissa; Mendelsohn, Cathy
Electron tomography reveals the steps in filovirus budding.
The filoviruses, Marburg and Ebola, are non-segmented negative-strand RNA viruses causing severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. The sequence of events that leads to release of filovirus particles from cells is poorly understood. Two contrasting mechanisms have been proposed, one proceeding via a "submarine-like" budding with the helical nucleocapsid emerging parallel to the plasma membrane, and the other via perpendicular "rocket-like" protrusion. Here we have infected cells with Marburg virus under BSL-4 containment conditions, and reconstructed the sequence of steps in the budding process in three dimensions using electron tomography of plastic-embedded cells. We find that highly infectious filamentous particles are released at early stages in infection. Budding proceeds via lateral association of intracellular nucleocapsid along its whole length with the plasma membrane, followed by rapid envelopment initiated at one end of the nucleocapsid, leading to a protruding intermediate. Scission results in local membrane instability at the rear of the virus. After prolonged infection, increased vesiculation of the plasma membrane correlates with changes in shape and infectivity of released viruses. Our observations demonstrate a cellular determinant of virus shape. They reconcile the contrasting models of filovirus budding and allow us to describe the sequence of events taking place during budding and release of Marburg virus. We propose that this represents a general sequence of events also followed by other filamentous and rod-shaped viruses. PMID:20442788
Welsch, Sonja; Kolesnikova, Larissa; Krähling, Verena; Riches, James D; Becker, Stephan; Briggs, John A G
Investigation B: Laminar confined coaxial entrance flow with heat generation
The results of a parametric study on the entrance flow region in a gas core nuclear reactor are presented. The physical system is modeled as laminar confined, coaxial flow with heat generation in the inner fluid. The governing equations include the boundary layer approximations and the assumptions of only radial radiative transport of energy represented as an energy diffusion term. The Von Mises transformation and a zeta transformation are used to transform the equations into nonlinear nonhomogeneous convective-diffusion equations. A unique combination of forward and backward difference equations which yields accurate results at moderate computational times, is used in the numerical method. Results show that the rapidly accelerating, heat generating inner stream actually shrinks in radius as it expands axially.
Bobba, G. K. M.; Weinstein, H.
Prenatal diethylstilbestrol exposure and performance on college entrance examinations.
The fetal rodent brain is permanently altered by exposure to sex hormones. Long-term effects of prenatal sex hormones on the human brain are far less clear. In order to explore such effects, we studied a measure of cognitive function among young adults who had been exposed in utero to a powerful synthetic estrogen. In a randomized clinical trial conducted at the University of Chicago in 1950-1952, 1646 pregnant women were randomly assigned to receive either high doses of diethylstilbestrol or placebo. Women in this study gave birth to 1653 liveborn infants, of whom 1603 (820 sons and 783 daughters) survived to their fifteenth birthday. College entrance examination scores were obtained for 42% of these offspring. No differences in test performance were seen among exposed daughters. Among sons, test scores were marginally higher among the exposed, probably due to chance. PMID:1398561
Wilcox, A J; Maxey, J; Herbst, A L
Repellence of the red bud borer Resseliella oculiperda from grafted apple trees by impregnation of rubber budding strips with essential oils.
The red bud borer Resseliella oculiperda (Rübs.) is a pest insect of apple trees when rootstocks are grafted with scion buds by 'shield budding'. The female midges are attracted to the wounds of the grafted buds where they lay their eggs. The larvae feed on the cambium and destroy the buds completely or partially, leading to bad union of the buds with the rootstocks. Budding strips are used very often by growers to bind scion buds to rootstocks. These strips cannot prevent midges from reaching the damaged tissue. Chemical treatments applied to the grafts and other types of strip do not provide better protection against the pest and may cause other risks for growers. In orchard experiments in 2000 and 2001, the authors evaluated the repellent action provided by three essential oils and five compounds of plant origin against the midges by impregnating budding strips with them. The essential oils of lavender, Lavandula angustifolia (P. Mill.), and alpha-terpineol decreased the infestation of buds by more than 95 and 80% respectively. The other potential repellents tested [the essential oil of Juniperus virginiana (L.), citronellal, the essential oil of Cinnamomum camphora (L.) J. Presl, R-carvone, linalool and R-fenchone] decreased infestation by 67, 66, 51, 45, 37 and 25% respectively. The formulation and commercial development of budding strips impregnated with lavender oil is discussed. PMID:17421054
van Tol, Rob W H M; Swarts, Henk J; van der Linden, Anton; Visser, J H
Supercooling Characteristics of Isolated Peach Flower Bud Primordia 1
The amount of unfrozen water in dormant peach (Prunus persica [L.] Batsch, cv Redhaven) flower buds, isolated primordia, and bud axes was determined during freezing using pulse nuclear magnetic resonance methods. Differential thermal analysis studies were conducted on whole buds and isolated primordia in the presence of ice nucleation. The results showed that some of the water in isolated primordia remained supercooled in the presence of ice nucleation. Although most tissue water froze (57.5%) following ice nucleation at ?2.5°C, a considerable amount of water was found to supercool. In the presence of ice nucleation, increased hydration of isolated primordia resulted in the elimination of the supercooling characteristic. The structural integrity of isolated primordia appeared to be essential for supercooling.
Rajashekar, C. B.
Supercooling characteristics of isolated peach flower bud primordia.
The amount of unfrozen water in dormant peach (Prunus persica [L.] Batsch, cv Redhaven) flower buds, isolated primordia, and bud axes was determined during freezing using pulse nuclear magnetic resonance methods. Differential thermal analysis studies were conducted on whole buds and isolated primordia in the presence of ice nucleation. The results showed that some of the water in isolated primordia remained supercooled in the presence of ice nucleation. Although most tissue water froze (57.5%) following ice nucleation at -2.5 degrees C, a considerable amount of water was found to supercool. In the presence of ice nucleation, increased hydration of isolated primordia resulted in the elimination of the supercooling characteristic. The structural integrity of isolated primordia appeared to be essential for supercooling. PMID:16666658
Rajashekar, C B
Genetic and QTL analyses of seed dormancy and preharvest sprouting resistance in the wheat germplasm CN10955
The inheritance and genetic linkage analysis for seed dormancy and preharvest sprouting (PHS) resistance were carried out\\u000a in an F8 recombinant inbred lines (RILs) derived from the cross between "CN19055" (white-grained, PHS-resistant) with locally adapted\\u000a Australian cultivar "Annuello" (white-grained, PHS-susceptible). Seed dormancy was assessed as germination index (GI7) while\\u000a assessment for preharvest sprouting resistance was based on whole head assay
F. C. Ogbonnaya; M. Imtiaz; G. Ye; P. R. Hearnden; E. Hernandez; R. F. Eastwood; M. van Ginkel; S. C. Shorter; J. M. Winchester
A QTL located on chromosome 4A associated with dormancy in white- and red-grained wheats of diverse origin
Improved resistance to preharvest sprouting in modern bread wheat (Triticum aestivum. L.) can be achieved via the introgression of grain dormancy and would reduce both the incidence and severity of damage due\\u000a to unfavourable weather at harvest. The dormancy phenotype is strongly influenced by environmental factors making selection\\u000a difficult and time consuming and this trait an obvious candidate for marker
D. Mares; K. Mrva; J. Cheong; K. Williams; B. Watson; E. Storlie; M. Sutherland; Y. Zou
Effect of exogenous gibberellic acid, abscisic acid, and benzylaminopurine on epicotyl dormancy of cultured herbaceous peony embryos
Epicotyl dormancy was broken in cultured peony (Paeonia lactiflora Pall.) embryos after topical application of agarose gels containing gibberellic acid, with optimum growth at 1.5 mM gibberellic acid. Addition of 100 µM abscisic acid to the medium resulted in complete inhibition of gibberellic acid-stimulated promotion of dormant epicotyls. Epicotyl dormancy was also broken in embryos by culture on media containing
Julie A. T. Buchheim; Len F. Burkhart; Martin M. Meyer
Mapping QTLs for grain dormancy on wheat chromosome 3A and the group 4 chromosomes, and their combined effect
A major QTL for grain dormancy, QPhs.ocs-3A.1, derived from the highly dormant wheat Zenkoujikomugi (Zen), has been identified in a study made under a controlled environment. Further investigations were needed to dissect the precise position and expression of QPhs.ocs-3A.1 under different field conditions because the ability to detect genetic loci for grain dormancy traits is compromised by environmental effects and
M. Mori; N. Uchino; M. Chono; K. Kato; H. Miura
A novel role for histone methyltransferase KYP/SUVH4 in the control of Arabidopsis primary seed dormancy.
• Seed dormancy controls germination and plays a crucial role in the life cycle of plants. Chromatin modifications are involved in the regulation of seed dormancy; however, little is known about the underlying mechanism. • KYP/SUVH4 is required for histone H3 lysine 9 dimethylation. Mutations in this gene cause increased seed dormancy. KYP/SUVH4-overexpressing Arabidopsis plants show decreased dormancy. KYP/SUVH4 expression is regulated by abscisic acid (ABA) and gibberellins (GA). The sensitivity of seed germination to ABA and paclobutrazol (PAC) is enhanced slightly in kryptonite-2 (kyp-2) and suvh4-2/suvh5 mutants, but weakened in KYP/SUVH4-overexpressing plants. • In the kyp-2 mutant, several dormancy-related genes, including DOG1 and ABI3, show increased expression levels, in agreement with a negative role for KYP/SUVH4 in gene transcription. • Genetic analysis showed that DOG1 and HUB1 are epistatic to KYP/SUVH4, suggesting that these genes regulate seed dormancy in the same genetic pathway. PMID:22122546
Zheng, Jian; Chen, Fengying; Wang, Zhi; Cao, Hong; Li, Xiaoying; Deng, Xin; Soppe, Wim J J; Li, Yong; Liu, Yongxiu
The first day of clinical trials for Gleevec, Bud and YvonneSite: DNA Interactive (www.dnai.org)
Interviewee: Bud DNAi Location:Applications>Genes and medicine>drug design>Bud's Story>The first patient The first patient Yvonne, Bud's wife, talks about the first day of the clinical trials in June of 1998
[Nuclear criteria for complete dormancy in the shoot apex of Fraxinus excelsior L].
The cytohistological criteria for the vegetative shoot apex dormancy in Fraxinus excelsior L. have been quantitatively established with the aid of 3 techniques: historadiography after incorporation of [(3)H]thymidine, mitotic index and nuclear cytophotometry by the two wavelength method. Nuclear DNA content, mitotic activity and DNA synthesis were compared in 3 different zones(apical zone, lateralzone, rib meristem) of the dormant and non-dormant apices. The periodical break in morphogenetic activity, in contrast to the vegetative period (April to July), is characterized by the absence of zonation and by the fact that meristematic cells remain in the G1 phase of the mitotic cycle. In Fraxinus excelsior L., the meristem dormancy is complete (no DNA synthesis, no mitotic activity and no DNA content greater than 2C). PMID:24442656
Cottignies, A
Microbial dormancy in batch cultures as a function of substrate-dependent mortality.
We present models and computational studies of dormancy in batch cultures to try to understand the relationship between reculturing time and death penalty for low substrate and the relative advantage of fast versus slow reawakening on the part of the bacteria. We find that the advantage goes to the faster waker for shorter reculturing times and lower mortality under low substrate, and moves to the slower waker as reculturing times and death penalty increase. The advantage returns again to the fast waker for very high death penalties. We use an explicit, continuous structure variable to represent dormancy so as to allow for flexibility in substrate usage on the part of dormant cells, and for a more mechanistic representation of the reawakening process. PMID:22004996
Ayati, Bruce P
Hierarchy of breast cancer cells: key to reverse dormancy for therapeutic intervention.
SummaryAn understanding of how cancer cells adapt dormancy would allow for targeted treatment. The current literature suggests that the cancer stem cells might be the major cells with the ability to become quiescent and to resist current drug treatment. The properties of cancer stem cells and healthy stem cells are functionally similar, thereby posing a challenge to target the dormant cells. The bone marrow is particularly a challenge because the dormant breast cancer cells are close to the endosteum, which is also home to the endogenous hematopoietic stem cells. Here we discuss how research studies could bring an understanding of the cellular and molecular interactions between the cancer stem cells and cells within the bone marrow microenvironment. This will allow for intervention to reverse dormancy for targeted treatment. The treatment will require studies within the normal organ functions to ensure treatment without toxicity. PMID:24833590
Bliss, Sarah A; Greco, Steven J; Rameshwar, Pranela
Dark CO2 Fixation in Gladiolus Cormels and Its Regulation during the Break of Dormancy 1
The increase in dark CO2 fixation during cold storage of Gladiolus x gandavensis van Houtte-type grandiflorus cormels is used to monitor changes in their state of dormancy. Dark fixation is also promoted by benzyladenine, which breaks cormel dormancy, and is inhibited by abscisic acid and gibberellin A3, which inhibit cormel germination. The rate of dark fixation by nondormant cormels is five times higher than that in dormant ones. Dark fixation is not due to microorganisms. It is temperature-dependent and can be measured stoichiometrically in vivo. The apex and base of the cormels accumulate more label than the central part. Dark fixation of both dormant and nondormant cormels is also promoted by imbibition in water. The fate of the labeled assimilates was followed by ion exchange chromatography.
Ginzburg, Chen
Reform of the College Entrance Examination: Ideology, Principles, and Policy Recommendations
Reform of the College Entrance Examination is trending toward simultaneous unification and diversification. The objective of reforming the entrance exam is to establish a college enrollment examination system that is primarily based on a unified test, which would assess students' abilities, appraise them on multiple levels, and classify them.…
Liu, Haifeng
Tidal truncation and barotropic convergence in a channel network tidally driven from opposing entrances
Residual circulation patterns in a channel network that is tidally driven from entrances on opposite sides are controlled by the temporal phasing and spatial asymmetry of the two forcing tides. The Napa\\/Sonoma Marsh Complex in San Francisco Bay, CA, is such a system. A sill on the west entrance to the system prevents a complete tidal range at spring tides
J. C. Warner; D. Schoellhamer; G. Schladow
36 CFR 71.8 - Validation and display of entrance permits.
...Public Property 1 2013-07-01 2013-07-01 false Validation and display of entrance permits. 71.8 Section 71...DEPARTMENT OF THE INTERIOR RECREATION FEES § 71.8 Validation and display of entrance permits. (a) Every...
Social Predictors of Unsuccessful Entrance into the Labour Market--A Socialization Process Perspective
Social determinants over the life course, including childhood family characteristics, were studied in predicting unsuccessful entrance into the labour market at the age of 31 years. Among men, unsuccessful entrance into the labour market was predicted prospectively by the mother's receptive attitude towards receiving social aid and contentment…
Ek, Ellen; Sovio, Ulla; Remes, Jouko; Jarvelin, Marjo-Riitta
Entrance heat transfer in rectangular ducts with constant axial energy input
The study of heat transfer in the entrance region of ducts with different cross-sections is important in engineering practice. This paper considers laminar, hydrodynamically fully developed flow in the thermal entrance regions of rectangular passages, emphasizing heat transfer aspects. By having a prescribed heating or cooling rate and considering the wall temperature to depend on the axial coordinate alone, the
A. Haji-Sheikh; J. V. Beck
Forensic value of gunpowder tattooing in identification of multiple entrance wounds from one bullet
Multiple entrance gunshot wounds can give useful information in forensic evaluation of deaths from homicide and suicide. Although the presence of multiple entrance gunshot wounds does not absolutely exclude the possibility of suicide, they are important to the forensic investigators and pathologists in cases of assault, attempted homicide and suicide as they provide important clues for determination of number of
Mehmet Tokdemir; Huseyin Kafadar; Abdurrahim Turkoglu; Turgay Bork
Mandating Early Childhood Entrance/Retention Assessment: Practices in the United States.
Analyzes early childhood evaluation policies as implemented by state departments of education in the United States. Data were collected from 48 states (2 states declined participation) concerning: (1) kindergarten and school entrance screening, (2) kindergarten exit and first grade entrance testing, and (3) testing in the primary grades. (NH)
Cannella, Galle S.; Reiff, Judith C.
Proposals for Standardizing and Improving the Policy of Adding Points on the Entrance Exam
This article reviews policies for adding points on the College Entrance Examination. It analyzes the rationales and specific implementation strategies of various policies for adding points on the entrance exam, as well as their advantages and pitfalls. Based on these observations and analysis, the author also offers policy recommendations on the…
Yuhong, Deng
Increased grain dormancy in white-grained wheat by introgression of preharvest sprouting tolerance QTLs
White-grained wheat cultivars have long been recognized to be less resistant to preharvest sprouting (PHS) than the red-grained ones. Previously two QTLs for grain dormancy, QPhs.ocs-3A.1 (QPhs-3AS) and QPhs.ocs-4A.1 (QPhs-4AL) were identified in a highly dormant Japanese red wheat, Zenkoujikomugi (Zen). Aiming at improvement of PHS tolerance in white-grained wheat, the introgression effect of these two QTLs in a white-grained
N. S. Kottearachchi; N. Uchino; K. Kato; H. Miura
Temperature effects on seed germination and expression of seed dormancy in wheat
Because preharvest sprouting decreases quantity and quality of wheat grain, researchers need effective protocols to assess\\u000a response to preharvest sprouting conditions. The aim of this study was to determine which temperature gives the greatest difference\\u000a in seed germination and expression of seed dormancy in 10 spring wheat genotypes. The genotypes were grown in the field near\\u000a Swift Current, Saskatchewan in
J. M. Nyachiro; F. R. Clarke; R. M. DePauw; R. E. Knox; K. C. Armstrong
Bibliography of References Related to Seed Dormancy and/or Germination in Higher Plants
This online bibliography is an extensive resource with a particular focus on early seed dormancy literature. Professor G.M. Simpson from the University of Saskatchewan has compiled this bibliography of 12,000 sources dating back to the 1890's. The bibliography has a user friendly search function and help page, and a history list of each session is available until the user exits the database.
Simpson, G. M.
Effect of carbon-disulphide on the dormancy and sprouting of seed-potatoes
Summary From research carried out in 1970 and 1971 with gas-tight containers it was confirmed that the dormancy of whole tubers can\\u000a be broken by a treatment with carbon disulphide (CS2). The dose for optimal sprouting lies between 12 1\\/2 and 25 ml\\/m3 room volume. A period of treatment of 3 days at 20C is generally sufficient. Treatment in spring of
C. P. Meijers
Effect of Pre-Treatments on Dormancy of Goldenrain-Tree (Koelreuteria paniculata Laxm.) Seeds
Goldenrain-tree (Koelreuteria paniculata Laxm.) is wide spread as an ornamental tree but the propagation is difficult because of pronounced seed dormancy. Unscarified seeds of K. paniculata Laxm. failed to germinate after any pre-treatments. Similarly, seeds soaked or soaked and redried without chilling were unable to germinate. However, seeds that were scarified, without soaking or soaking-redrying, gave 44% germination after 60
Shafiq Rehman; In-Hwan Park
Alleviation of Seed Dormancy in the Desert Forb Zygophyllum simplex L. from Pakistan
Zygophyllum simplexL. is a succulent annual that grows on the coastal and inland saline flats around Karachi, Pakistan. The seeds are moderately salt tolerant during germination. Germination ofZygophyllum simplexseeds under various salinity, proline, betaine, GA and kinetin treatments was determined. Proline (0.1 and 1 mm) and betaine (0.1 and 1 mm) alleviated the innate dormancy of seeds, and germination reached
Physical and physiological dormancy in black henbane ( Hyoscyamus niger L.) seeds
Aim of this study was to investigate the nature of dormancy in black henbane (Hyoscyamus niger) seeds which have low germination rate under normal laboratory conditions. To do this, before placing the seeds in Petri\\u000a dishes, they were soaked in 5,10 and 15 mg\\/L GA; 1,2 and 3% H2SO4, 15 mg\\/L GA + 1% H2SO4, 0.01 M KNO3 solutions, tap
Cüneyt çrak; Kudret Kevseroglu; Birsen Sa?lam
Dormancy of Nicotiana benthamiana seeds can be broken by different compounds
The influence of after-ripening, sodium nitroprusside, potassium ferricyanide, cyanide, paclobutrazol and nitrite on germination\\u000a of seeds of Nicotiana benthamiana was investigated as well as the influence of plant hormones such as gibberellins and abscisic acid. Dormancy of N. benthamiana seeds was broken by all treatments except treatments with abscisic acid, paclobutrazol and gibberellic acid (GA3). Gibberellins had an interesting effect
Andrea Wünschová; Veronika Be?ová; Helena Vlašínová; Ladislav Havel
Genetic analysis of adaptive syndromes interrelated with seed dormancy in weedy rice ( Oryza sativa )
Seed dormancy in rice interrelates to the weedy characteristics shattering, awn, black hull color, and red pericarp color. A cross between the weedy strain SS18-2 and the breeding line EM93-1 was developed to investigate the genetic basis and adaptive significance of these interrelationships. These characteristics or their components differed in average degree of dominance from -0.8 to 1.5, in heritability
Xing-You Gu; Shahryar F. Kianian; Gary A. Hareland; Barry L. Hoffer; Michael E. Foley
Changes in Abscisic Acid Biosynthesis and Catabolism during Dormancy Breaking in Fagus sylvatica Embryo
. At harvest, embryos of Fagus sylvatica are dormant. A cold pretreatment without medium at 30% moisture content allowed them to germinate. A comparison of the abscisic\\u000a acid (ABA) content before and after the pretreatment has no significant relevance since dormancy is expressed during the culture\\u000a at 23°C. During this culture, both de novo biosynthesis and conjugate hydrolysis contributed to
M. T. Le Page-Degivry; G. Garello; P. Barthe
Release of sunflower seed dormancy by cyanide: cross-talk with ethylene signalling pathway.
Freshly harvested sunflower (Helianthus annuus L.) seeds are considered to be dormant because they fail to germinate at relatively low temperatures (10 degrees C). This dormancy results mainly from an embryo dormancy and disappears during dry storage. Although endogenous ethylene is known to be involved in sunflower seed alleviation of dormancy, little attention had been paid to the possible role of cyanide, which is produced by the conversion of 1-aminocyclopropane 1-carboxylic acid to ethylene, in this process. The aims of this work were to investigate whether exogenous cyanide could improve the germination of dormant sunflower seeds and to elucidate its putative mechanisms of action. Naked dormant seeds became able to germinate at 10 degrees C when they were incubated in the presence of 1 mM gaseous cyanide. Other respiratory inhibitors showed that this effect did not result from an activation of the pentose phosphate pathway or the cyanide-insensitive pathway. Cyanide stimulated germination of dormant seeds in the presence of inhibitors of ethylene biosynthesis, but its improving effect required functional ethylene receptors. It did not significantly affect ethylene production and the expression of genes involved in ethylene biosynthesis or in the first steps of ethylene signalling pathway. However, the expression of the transcription factor Ethylene Response Factor 1 (ERF1) was markedly stimulated in the presence of gaseous cyanide. It is proposed that the mode of action of cyanide in sunflower seed dormancy alleviation does not involve ethylene production and that ERF1 is a common component of the ethylene and cyanide signalling pathways. PMID:18448476
Oracz, Krystyna; El-Maarouf-Bouteau, Hayat; Bogatek, Renata; Corbineau, Françoise; Bailly, Christophe
Temperature-mediated changes in seed dormancy and light requirement for Penstemon palmeri (Scrophulariaceae)
Penstemon palmeri is a short-lived perennial herb colonizing disturbed sites in semiarid habitats in the western US. In this study seed was harvested from six native and four seeded populations during two consecutive years. In laboratory germination trials at constant 15C, considerable between-lot variation in primary dormancy and light requirement was observed. Four weeks of moist chilling (1C) induced secondary
S. G. Kitchen; S. E. Meyer
Behavioral and metabolic aspects of low temperature dormancy in the brown bullhead, Ictalurus nebulosus
1.Behavioral and physiological measurements were made during the winter at low temperatures to evaluate cold temperature dormancy in the brown bullhead.2.At 17°C and when slowly cooled to 3°C the bullheads often buried themselves in the mud (Fig. 1). Animals buried at 3°C were not immobilized and would emerge from the mud following a disturbance.3.No readjustment of the thermoregulatory mechanisms was
Larry I. Crawshaw; Daniel E. Lemons; Marsha Parmer; Jeffrey M. Messing
Dormancy break of celery (Apium graveolens L.) seeds by plant derived smoke extract
Seed dormancy of a highly-dormant cultivar of celery (Apium graveolens L.) was broken by combinations of plant-derived smoke extract or N6-benzyladenine (BA) and gibberellins A4\\/7 (GA4\\/7) in the dark at temperatures between 18 and 26°C. A less dormant cultivar which responded to GA4\\/7 alone showed no additional response to smoke extract or BA. Neither smoke extract nor BA affected either
T. H. Thomas; J. Staden
Association studies of dormancy and cooking quality traits in direct-seeded indica rice.
Association analysis was applied to a panel of accessions of Assam rice (indica) using 98 SSR markers for dormancy-related traits and cooking quality. Analysis of population structure revealed 10 subgroups in the population. The mean r(2) and D' value for all intrachromosomal loci pairs was 0.24 and 0.51, respectively. Linkage disequilibrium between linked markers decreased with distance. Marker-trait associations were investigated using the unified mixed-model approach, considering both population structure (Q) and kinship (K). Genome-wide scanning, detected a total of seven significant marker-trait associations (P < 0.01), with the R(2) values ranging from 12.0 to 18.0%. The significant marker associations were for grain dormancy (RM27 on chromosome 2), ?-amylase activity (RM27 and RM234 on chromosomes 2 and 7, respectively), germination (RM27 and RM106 on chromosome 2), amylose (RM282 on chromosome 3) and grain length elongation ratio (RM142 on chromosome 4). The present study revealed the association of marker RM27 with traits like dormancy, ?-amylase activity and germination. Simple correlation analysis of these traits revealed that these traits were positively correlated with each other and this marker may be useful for simultaneous improvement of these traits. The study indicates the presence of novel QTLs for a few traits under consideration. The study reveals association of traits like dormancy, ?-amylase activity, germination, amylose content, grain length elongation ratio with SSR markers indicating the feasibility of undertaking association analysis in conjunction with germplasm characterization. PMID:24840818
Rathi, Sunayana; Pathak, K; Yadav, R N S; Kumar, B; Sarma, R N
Background Seed dormancy is controlled by the physiological or structural properties of a seed and the external conditions. It is induced as part of the genetic program of seed development and maturation. Seeds with deep physiological embryo dormancy can be stimulated to germinate by a variety of treatments including cold stratification. Hormonal imbalance between germination inhibitors (e.g. abscisic acid) and growth promoters (e.g. gibberellins) is the main cause of seed dormancy breaking. Differences in the status of hormones would affect expression of genes required for germination. Proteomics offers the opportunity to examine simultaneous changes and to classify temporal patterns of protein accumulation occurring during seed dormancy breaking and germination. Analysis of the functions of the identified proteins and the related metabolic pathways, in conjunction with the plant hormones implicated in seed dormancy breaking, would expand our knowledge about this process. Results A proteomic approach was used to analyse the mechanism of dormancy breaking in Norway maple seeds caused by cold stratification, and the participation of the abscisic (ABA) and gibberellic (GA) acids. Forty-four proteins showing significant changes were identified by mass spectrometry. Of these, eight spots were identified as water-responsive, 18 spots were ABA- and nine GA-responsive and nine spots were regulated by both hormones. The classification of proteins showed that most of the proteins associated with dormancy breaking in water were involved in protein destination. Most of the ABA- and GA-responsive proteins were involved in protein destination and energy metabolism. Conclusion In this study, ABA was found to mostly down-regulate proteins whereas GA up-regulated proteins abundance. Most of the changes were observed at the end of stratification in the germinated seeds. This is the most active period of dormancy breaking when seeds pass from the quiescent state to germination. Seed dormancy breaking involves proteins of various processes but the proteasome proteins, S-adenosylmethionine synthetase, glycine-rich RNA binding protein, ABI3-interacting protein 1, EF-2 and adenosylhomocysteinase are of particular importance. The effect of exogenously applied hormones was not a determining factor for total inhibition (ABA) or stimulation (GA) of Norway maple seed dormancy breaking and germination but proteomic data has proven these hormones play a role.
Pawlowski, Tomasz A
Science Shorts: Project BudBurst--Analyzing Data
Project BudBurst is a national program intended to get students and other "citizen scientists" to participate in a real study about plants, the environment, and climate change. It also provides an excellent opportunity for students to build data-analysis skills. A collaboration of several agencies and universities, the program began last year and…
Davis, Kimberly J.; Coskie, Tracy L.
Mechanisms of Budding of Nanoscale Particles through Lipid Bilayers
We examine the budding of a nanoscale particle through a lipid bilayer using molecular dynamics simulations, free energy calculations, and an elastic theory, with the aim of determining the extent to which equilibrium elasticity theory can describe the factors that control the mechanism and efficiency of budding. The particle is a smooth sphere which experiences attractive interactions to the lipid head groups. Depending on the parameters, we observe four classes of dynamical trajectories: particle adhesion to the membrane, stalled partially wrapped states, budding followed by scission, and membrane rupture. In most regions of parameter space we find that the elastic theory agrees nearly quantitatively with the simulated phase behavior as a function of adhesion strength, membrane bending rigidity, and particle radius. However, at parameter values near the transition between particle adhesion and budding, we observe long-lived partially wrapped states which are not captured by existing elastic theories. These states could constrain the accessible system parameters for those enveloped viruses or drug delivery vehicles which rely on exo- or endocytosis for membrane transport.
Ruiz-Herrero, Teresa; Velasco, Enrique; Hagan, Michael F.
Stem diameter changes before bud opening in Zelkova serrata saplings.
It is well known that stems of woody plants shrink and swell diurnally. These fluctuations of stem diameter are induced mainly by the changes of water contents in plants, which are caused by the combination of leaf transpiration and root absorption of water. This implies that dormant-like deciduous broadleaved trees in a leafless state should show no or less changes in stem diameter. However, some physiological activities in woody plants are also known to precede their winter bud opening. Whether and how diameter changes occur in deciduous tree stems during winter was investigated using Zelkova serrata saplings in a leafless state. Measurements of stem diameter changes were done for more than 4 months continuously. The saplings showed distinct diameter changes with periodicities from diurnal to a few weeks, and these changes were initiated 2 months before winter bud opening. These results indicate that some physiological and/or developmental activities occur in the stem of deciduous trees before winter bud opening, and do not correspond to changes in water relations as a result of leaf transpiration. These internal activities cause fluctuations in stem diameter prior to winter bud opening in deciduous trees. PMID:12605295
Yoda, Kiyotsugu; Wagatsuma, Hiromichi; Suzuki, Mitsuo; Suzuki, Hitoshi
Preparation and budding growth of whiskers in a homogeneous system
Ca10(PO4)6(OH)2 (HAP) and NH4Al(OH)2CO3·H2O (AACHH) whiskers were prepared by a homogeneous precipitation method based on urea hydrolysis reaction. To clarify the growth process of whiskers in the homogeneous system, XRD and SEM results of the products obtained at different reaction time were investigated in detail. A novel observation about budding growth in preparing both whiskers was described. It was indicated that the growth of whiskers went through three stages, which were oversaturation, nucleation, and budding growth. The growth units of whiskers budded from the surfaces of substrates, which were crystallized flakes for HAP preparation and amorphous spherical nuclei for AACHH preparation. Subsequently, the whiskers grew up accompanying with the disappearing substrates. One-dimensional whiskers with fine morphology and large slenderness ratio were finally obtained. Besides, according to the crystal growth and the interface diffusion theories, the effects of the templates and the budding growth mechanism were discussed.
Zhang, Zhan Hui; Chen, Li; Liu, Heng; Chen, Chang Lian; Wang, Shu Lin; Huang, Zhi Liang
Ras recruits mitotic exit regulator Lte1 to the bud cortex in budding yeast
ACdc25 family protein Lte1 (low temperature essential) is essential for mitotic exit at a lowered temperature and has been presumed to be a guanine nucleotide exchange factor (GEF) for a small GTPase Tem1, which is a key regulator of mitotic exit. We found that Lte1 physically associates with Ras2-GTP both in vivo and in vitro and that the Cdc25 homology domain (CHD) of Lte1 is essential for the interaction with Ras2. Furthermore, we found that the proper localization of Lte1 to the bud cortex is dependent on active Ras and that the overexpression of a derivative of Lte1 without the CHD suppresses defects in mitotic exit of a ?lte1 mutant and a ?ras1 ?ras2 mutant. These results suggest that Lte1 is a downstream effector protein of Ras in mitotic exit and that the Ras GEF domain of Lte1 is not essential for mitotic exit but required for its localization.
Yoshida, Satoshi; Ichihashi, Ryuji; Toh-e, Akio
AXR1 acts after lateral bud formation to inhibit lateral bud growth in Arabidopsis.
The AXR1 gene of Arabidopsis is required for many auxin responses. The highly branched shoot phenotype of mature axr1 mutant plants has been taken as genetic evidence for a role of auxin in the control of shoot branching. We compared the development of lateral shoots in wild-type Columbia and axr1-12 plants. In the wild type, the pattern of lateral shoot development depends on the developmental stage of the plant. During prolonged vegetative growth, axillary shoots arise and develop in a basal-apical sequence. After floral transition, axillary shoots arise rapidly along the primary shoot axis and grow out to form lateral inflorescences in an apical-basal sequence. For both patterns, the axr1 mutation does not affect the timing of axillary meristem formation; however, subsequent lateral shoot development proceeds more rapidly in axr1 plants. The outgrowth of lateral inflorescences from excised cauline nodes of wild-type plants is inhibited by apical auxin. axr1-12 nodes are resistant to this inhibition. These results provide evidence for common control of axillary growth in both patterns, and suggest a role for auxin during the late stages of axillary shoot development following the formation of the axillary bud and several axillary leaf primordia. PMID:10557232
Stirnberg, P; Chatfield, S P; Leyser, H M
The effects of (S)-(+)-carvone treatments on seed potato tuber dormancy and sprouting
Summary Potato seed tubers may suffer from premature sprouting during storage, thus limiting their suitability for cultivation. Commonly\\u000a used sprout suppressant treatments negatively affect but viability and therefore a reliable method to inhibit bud development\\u000a must still be found for seed tubers. The monoterpene carvone ((S)-(+)-carvone) was tested in small scale experiments. The\\u000a vapour of this compound fully inhibited bud growth
Carlo Sorce; Roberto Lorenzi; Paolo Ranalli
The Roles of Bud-Site-Selection Proteins during Haploid Invasive Growth in Yeast
In haploid strains of Saccharomyces cerevisiae, glucose depletion causes invasive growth, a foraging response that requires a change in budding pattern from axial to unipolar-distal. To begin to address how glucose influences budding pattern in the haploid cell, we examined the roles of bud-site-selection proteins in invasive growth. We found that proteins required for bipolar budding in diploid cells were
Paul J. Cullen; George F. Sprague
Increased ABA sensitivity results in higher seed dormancy in soft white spring wheat cultivar 'Zak'.
As a strategy to increase the seed dormancy of soft white wheat, mutants with increased sensitivity to the plant hormone abscisic acid (ABA) were identified in mutagenized grain of soft white spring wheat "Zak". Lack of seed dormancy is correlated with increased susceptibility to preharvest sprouting in wheat, especially those cultivars with white kernels. ABA induces seed dormancy during embryo maturation and inhibits the germination of mature grain. Three mutant lines called Zak ERA8, Zak ERA19A, and Zak ERA19B (Zak ENHANCED RESPONSE to ABA) were recovered based on failure to germinate on 5 ?M ABA. All three mutants resulted in increased ABA sensitivity over a wide range of concentrations such that a phenotype can be detected at very low ABA concentrations. Wheat loses sensitivity to ABA inhibition of germination with extended periods of dry after-ripening. All three mutants recovered required more time to after-ripen sufficiently to germinate in the absence of ABA and to lose sensitivity to 5 ?M ABA. However, an increase in ABA sensitivity could be detected after as long as 3 years of after-ripening using high ABA concentrations. The Zak ERA8 line showed the strongest phenotype and segregated as a single semi-dominant mutation. This mutation resulted in no obvious decrease in yield and is a good candidate gene for breeding preharvest sprouting tolerance. PMID:23212773
Schramm, Elizabeth C; Nelson, Sven K; Kidwell, Kimberlee K; Steber, Camille M
Induction of 9-cis-epoxycarotenoid dioxygenase in Arabidopsis thaliana seeds enhances seed dormancy
Full understanding of mechanisms that control seed dormancy and germination remains elusive. Whereas it has been proposed that translational control plays a predominant role in germination, other studies suggest the importance of specific gene expression patterns in imbibed seeds. Transgenic plants were developed to permit conditional expression of a gene encoding 9-cis-epoxycarotenoid dioxygenase 6 (NCED6), a rate-limiting enzyme in abscisic acid (ABA) biosynthesis, using the ecdysone receptor-based plant gene switch system and the ligand methoxyfenozide. Induction of NCED6 during imbibition increased ABA levels more than 20-fold and was sufficient to prevent seed germination. Germination suppression was prevented by fluridone, an inhibitor of ABA biosynthesis. In another study, induction of the NCED6 gene in transgenic seeds of nondormant mutants tt3 and tt4 reestablished seed dormancy. Furthermore, inducing expression of NCED6 during seed development suppressed vivipary, precocious germination of developing seeds. These results indicate that expression of a hormone metabolism gene in seeds can be a sole determinant of dormancy. This study opens the possibility of developing a robust technology to suppress or promote seed germination through engineering pathways of hormone metabolism.
Martinez-Andujar, Cristina; Ordiz, M. Isabel; Huang, Zhonglian; Nonogaki, Mariko; Beachy, Roger N.; Nonogaki, Hiroyuki
Dormancy of Cancer Cells with Suppression of AKT Activity Contributes to Survival in Chronic Hypoxia
A hypoxic microenvironment in tumors has been recognized as a cause of malignancy or resistance to various cancer therapies. In contrast to recent progress in understanding the acute response of cancer cells to hypoxia, the characteristics of tumor cells in chronic hypoxia remain elusive. We have identified a pancreatic cancer cell line, AsPC-1, that is exceptionally able to survive for weeks under 1% oxygen conditions while most tested cancer cell lines die after only some days under these conditions. In chronic hypoxia, AsPC-1 cells entered a state of dormancy characterized by no proliferation, no death, and metabolic suppression. They reversibly switched to active status after being placed again in optimal culture conditions. ATP turnover, an indicator of energy demand, was markedly decreased and accompanied by reduced AKT phosphorylation. Forced activation of AKT resulted in increased ATP turnover and massive cell death in vitro and a decreased number of dormant cells in vivo. In contrast to most cancer cell lines, primary-cultured colorectal cancer cells easily entered the dormant status with AKT suppression under hypoxia combined with growth factor–depleted conditions. Primary colorectal cancer cells in dormancy were resistant to chemotherapy. Thus, the ability to survive in a deteriorated microenvironment by entering into dormancy under chronic hypoxia might be a common property among cancer cells. Targeting the regulatory mechanism inducing this dormant status could provide a new strategy for treating cancer.
Endo, Hiroko; Okuyama, Hiroaki; Ohue, Masayuki; Inoue, Masahiro
In silico discovery of the dormancy regulons in a number of Actinobacteria genomes
Mycobacterium tuberculosis is a dangerous Actinobacteria infecting nearly one third of the human population. It becomes dormant and phenotypically drug resistant in response to stresses. An important feature of the M. tuberculosis pathogenesis is the prevalence of latent infection without disease, making understanding of the mechanisms used by the bacteria to exist in this state and to switch to metabolically active infectious form a vital problem to consider. M. tuberculosis dormancy is regulated by the three-component regulatory system of two kinases (DosT and DevS) and transcriprional regulator (DevR). DevR activates transcription of a set of genes, which allow the bacteria to survive long periods of anaerobiosis, and may be important for long-term survival within the host during latent infection. The DevR-regulon is studied experimentally in M. tuberculosis and few other phylogenetically close Mycobacteria spp. As many other two-component systems, the devRS operon is autoregulated. However, the mechanism of the dormancy is not completely clear even for these bacteria and there is no data describing the dormancy regulons in other species.
Gerasimova, Anna; Dubchak, Inna; Arkin, Adam; Gelfand, Mikhail
Survival and Dormancy of Mycobacterium avium subsp. paratuberculosis in the Environment
The survival of Mycobacterium avium subsp. paratuberculosis was studied by culture of fecal material sampled at intervals for up to 117 weeks from soil and grass in pasture plots and boxes. Survival for up to 55 weeks was observed in a dry fully shaded environment, with much shorter survival times in unshaded locations. Moisture and application of lime to soil did not affect survival. UV radiation was an unlikely factor, but infrared wavelengths leading to diurnal temperature flux may be the significant detrimental component that is correlated with lack of shade. The organism survived for up to 24 weeks on grass that germinated through infected fecal material applied to the soil surface in completely shaded boxes and for up to 9 weeks on grass in 70% shade. The observed patterns of recovery in three of four experiments and changes in viable counts were indicative of dormancy, a hitherto unreported property of this taxon. A dps-like genetic element and relA, which are involved in dormancy responses in other mycobacteria, are present in the M. avium subsp. paratuberculosis genome sequence, providing indirect evidence for the existence of physiological mechanisms enabling dormancy. However, survival of M. avium subsp. paratuberculosis in the environment is finite, consistent with its taxonomic description as an obligate parasite of animals.
Whittington, Richard J.; Marshall, D. Jeff; Nicholls, Paul J.; Marsh, Ian B.; Reddacliff, Leslie A.
Breaking seed dormancy in Hippophae salicifolia, a high value medicinal plant.
Seed dormancy is an important limiting factor in exploitation of an economically important species to its fullest. Hippophae salicifolia D. Don (seabuckthorn), a rich source of medicinal metabolites shows both exogenous and endogenous dormancy. Evidently, we recorded a high seed viability (94 %) but poor germination (22 %) of untreated seeds. We applied different pre-sowing seed priming treatments including NaCl (50, 100, 200, 500 mM), KNO3 (0.1, 0.2, 0.3 %), Thiourea (1, 2, 3 %), GA3 (100, 250, 500 mg/L), Sulphuric acid (98 %) and cold (4 °C) and warm water (65 °C) stratifications to explore improvements in its germination percentage, if any. We found KNO3 (0.1 %) and Thiourea (1 %) treatments to be superior to other methods for enhancement of mean seed germination percentage of H. salicifolia. Considering the practical applicability and cost effectiveness, these treatments can be applied to overcome seed dormancy and recommended for mass multiplication through seeds of H. salicifolia. PMID:23573034
Gupta, Sanjay Mohan; Pandey, Pankaj; Grover, Atul; Ahmed, Zakwan
Proteomic Analysis of Embryogenesis and the Acquisition of Seed Dormancy in Norway Maple (Acer platanoides L.)
The proteome of zygotic embryos of Acer platanoides L. was analyzed via high-resolution 2D-SDS-PAGE and MS/MS in order to: (1) identify significant physiological processes associated with embryo development; and (2) identify changes in the proteome of the embryo associated with the acquisition of seed dormancy. Seventeen spots were identified as associated with morphogenesis at 10 to 13 weeks after flowering (WAF). Thirty-three spots were associated with maturation of the embryo at 14 to 22 WAF. The greatest changes in protein abundance occurred at 22 WAF, when seeds become fully mature. Overall, the stage of morphogenesis was characterized by changes in the abundance of proteins (tubulins and actin) associated with the growth and development of the embryo. Enzymes related to energy supply were especially elevated, most likely due to the energy demand associated with rapid growth and cell division. The stage of maturation is crucial to the establishment of seed dormancy and is associated with a higher abundance of proteins involved in genetic information processing, energy and carbon metabolism and cellular and antioxidant processes. Results indicated that a glycine-rich RNA-binding protein and proteasome proteins may be directly involved in dormancy acquisition control, and future studies are warranted to verify this association.
Staszak, Aleksandra Maria; Pawlowski, Tomasz Andrzej
Global gene expression analysis identifies molecular pathways distinguishing blastocyst dormancy and activation.
Delayed implantation (embryonic diapause) occurs when the embryo at the blastocyst stage achieves a state of suspended animation. During this period, blastocyst growth is very slow, with minimal or no cell division. Nearly 100 mammals in seven different orders undergo delayed implantation, but the underlying molecular mechanisms that direct this process remain largely unknown. In mice, ovariectomy before preimplantation ovarian estrogen secretion on day 4 of pregnancy initiates blastocyst dormancy, which normally lasts for 1-2 weeks by continued progesterone treatment, although blastocyst survival decreases with time. An estrogen injection rapidly activates blastocysts and initiates their implantation in the progesterone-primed uterus. Using this model, here we show that among approximately 20,000 genes examined, only 229 are differentially expressed between dormant and activated blastocysts. The major functional categories of altered genes include the cell cycle, cell signaling, and energy metabolic pathways, particularly highlighting the importance of heparin-binding epidermal growth factor-like signaling in blastocyst-uterine crosstalk in implantation. The results provide evidence that the two different physiological states of the blastocyst, dormancy and activation, are molecularly distinguishable in a global perspective and underscore the importance of specific molecular pathways in these processes. This study has identified candidate genes that provide a scope for in-depth analysis of their functions and an opportunity for examining their relevance to blastocyst dormancy and activation in numerous other species for which microarray analysis is not available or possible due to very limited availability of blastocysts. PMID:15232000
Hamatani, Toshio; Daikoku, Takiko; Wang, Haibin; Matsumoto, Hiromichi; Carter, Mark G; Ko, Minoru S H; Dey, Sudhansu K
Identification of cis-elements that regulate gene expression during initiation of axillary bud outgrowth in Arabidopsis.
Growth regulation associated with dormancy is an essential element in plant life cycles. To reveal regulatory mechanisms of bud outgrowth, we analyzed transcriptomes of axillary shoots before and after main stem decapitation in Arabidopsis (Arabidopsis thaliana). We searched for any enriched motifs among the upstream regions of up-regulated and down-regulated genes after decapitation. The promoters of down-regulated genes were enriched for TTATCC motifs that resemble the sugar-repressive element, whereas the promoters of up-regulated genes were enriched for GGCCCAWW and AAACCCTA, designated Up1 and Up2, respectively. Transgenic plants harboring a reporter gene driven by a tandem repeat of the elements were produced to analyze their function in vivo. Sugar-repressive element-mediated gene expression was down-regulated by the application of sugars but was unaffected after decapitation. In contrast, expression driven by the repeat containing both Up1 and Up2 was up-regulated after decapitation, although the Up1 or Up2 repeat alone failed to induce reporter gene expression in axillary shoots. In addition, disruption of both Up1 and Up2 elements in a ribosomal protein gene abolished the decapitation-induced expression. Ontological analysis demonstrated that up-regulated genes with Up elements were disproportionately predicted to function in protein synthesis and cell cycle. Up1 is similar to an element known to be a potential target for TCP (TEOSINTE BRANCHED1, CYCLOIDEA, PCFs family) transcription factor(s), which regulate expression of cell cycle-related and ribosomal protein genes. Our data indicate that Up1-mediated transcription of protein synthesis and cell cycle genes is an important regulatory step during the initiation of axillary shoot outgrowth induced by decapitation. PMID:15908603
Tatematsu, Kiyoshi; Ward, Sally; Leyser, Ottoline; Kamiya, Yuji; Nambara, Eiji
Induction of ectopic taste buds by SHH reveals the competency and plasticity of adult lingual epithelium.
Taste buds are assemblies of elongated epithelial cells, which are innervated by gustatory nerves that transmit taste information to the brain stem. Taste cells are continuously renewed throughout life via proliferation of epithelial progenitors, but the molecular regulation of this process remains unknown. During embryogenesis, sonic hedgehog (SHH) negatively regulates taste bud patterning, such that inhibition of SHH causes the formation of more and larger taste bud primordia, including in regions of the tongue normally devoid of taste buds. Here, using a Cre-lox system to drive constitutive expression of SHH, we identify the effects of SHH on the lingual epithelium of adult mice. We show that misexpression of SHH transforms lingual epithelial cell fate, such that daughter cells of lingual epithelial progenitors form cell type-replete, onion-shaped taste buds, rather than non-taste, pseudostratified epithelium. These SHH-induced ectopic taste buds are found in regions of the adult tongue previously thought incapable of generating taste organs. The ectopic buds are composed of all taste cell types, including support cells and detectors of sweet, bitter, umami, salt and sour, and recapitulate the molecular differentiation process of endogenous taste buds. In contrast to the well-established nerve dependence of endogenous taste buds, however, ectopic taste buds form independently of both gustatory and somatosensory innervation. As innervation is required for SHH expression by endogenous taste buds, our data suggest that SHH can replace the need for innervation to drive the entire program of taste bud differentiation. PMID:24993944
Castillo, David; Seidel, Kerstin; Salcedo, Ernesto; Ahn, Christina; de Sauvage, Frederic J; Klein, Ophir D; Barlow, Linda A
Entrance surface dose in cerebral interventional radiology procedures
At the Instituto Nacional de Neurología y Neurocirugía (INNN) diagnostic as well as therapeutic procedures of interventional radiology are carried out. Since the procedures can last from some minutes to several hours, the absorbed dose for the patient could increase dangerously. An investigation had begun in order to determine the entrance surface dose (ESD) using 25 thermoluminiscent dosimeters TLD-100 and 8 strips of 15 ×1 cm2 of Gafchromic XR-QA2 film bound in a holder of 15×15 cm2 in the posteroanterior (PA) and lateral (LAT) positions during all the procedure. The results show that maximum ESD could be from 0.9 to 2.9 Gy for the PA position and between 1.6 and 2.5 Gy for the lateral position. The average ESD was between 0.7 and 1.3 Gy for the PA position, and from 0.44 to 1.1 Gy for the lateral position in a therapeutic procedure.
Barrera-Rico, M.; López-Rendón, X.; Rivera-Ordóńez, C. E.; Gamboa-deBuen, I.
At the Instituto Nacional de Neurologia y Neurocirugia (INNN) diagnostic as well as therapeutic procedures of interventional radiology are carried out. Since the procedures can last from some minutes to several hours, the absorbed dose for the patient could increase dangerously. An investigation had begun in order to determine the entrance surface dose (ESD) using 25 thermoluminiscent dosimeters TLD-100 and 8 strips of 15 Multiplication-Sign 1 cm{sup 2} of Gafchromic XR-QA2 film bound in a holder of 15 Multiplication-Sign 15 cm{sup 2} in the posteroanterior (PA) and lateral (LAT) positions during all the procedure. The results show that maximum ESD could be from 0.9 to 2.9 Gy for the PA position and between 1.6 and 2.5 Gy for the lateral position. The average ESD was between 0.7 and 1.3 Gy for the PA position, and from 0.44 to 1.1 Gy for the lateral position in a therapeutic procedure.
Barrera-Rico, M.; Lopez-Rendon, X.; Rivera-Ordonez, C. E.; Gamboa-deBuen, I. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, 04510 DF (Mexico); Instituto Nacional de Neurologia y Neurocirugia Manuel Velasco Suarez, 14269 DF (Mexico); Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, 04510 DF (Mexico)
Wax Ester Synthesis is Required for Mycobacterium tuberculosis to Enter In Vitro Dormancy
Mycobacterium tuberculosis (Mtb) is known to produce wax esters (WE) when subjected to stress. However, nothing is known about the enzymes involved in biosynthesis of WE and their role in mycobacterial dormancy. We report that two putative Mtb fatty acyl-CoA reductase genes (fcr) expressed in E. coli display catalytic reduction of fatty acyl-CoA to fatty aldehyde and fatty alcohol. Both enzymes (FCR1/Rv3391) and FCR2/Rv1543) show