who developed staining method for differentiating between groups of bacteria
Hans Christian Gram
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and publications. When articles are submitted to journals, each journal may or may not apply house style to the postprint version. Preprint versions contain whichever style the author happened to use. Even style regimens that use lowercase for the adjectives 'gram-positive' and 'gram-negative' still use capital for 'Gram stain'. Gram stain Gram stain or Gram staining, also called Gram's method, is a method of staining used to distinguish and classify bacterial species into two large groups (gram-positive and gram-negative). The name comes from the Danish bacteriologist Hans Christian Gram, who developed the technique. Gram staining differentiates bacteria by the chemical
Gram stain
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Gram stain Gram stain or Gram staining, also called Gram's method, is a method of staining used to distinguish and classify bacterial species into two large groups (gram-positive and gram-negative). The name comes from the Danish bacteriologist Hans Christian Gram, who developed the technique. Gram staining differentiates bacteria by the chemical and physical properties of their cell walls by detecting peptidoglycan, which is present in the cell wall of Gram-positive bacteria. Gram-negative cells also contain peptidoglycan, but a very small layer of it that is dissolved when the alcohol is added. This is why the cell loses its initial color
Gram stain
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and publications. When articles are submitted to journals, each journal may or may not apply house style to the postprint version. Preprint versions contain whichever style the author happened to use. Even style regimens that use lowercase for the adjectives 'gram-positive' and 'gram-negative' still use capital for 'Gram stain'. Gram stain Gram stain or Gram staining, also called Gram's method, is a method of staining used to distinguish and classify bacterial species into two large groups (gram-positive and gram-negative). The name comes from the Danish bacteriologist Hans Christian Gram, who developed the technique. Gram staining differentiates bacteria by the chemical
Gram stain
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surgery safer for patients. In the years between 1876 and 1884 Robert Koch provided much insight into infectious diseases. He was one of the first scientists to focus on the isolation of bacteria in pure culture. This gave rise to the germ theory, a certain microorganism being responsible for a certain disease. He developed a series of criteria around this that have become known as the Koch's postulates. A major milestone in medical microbiology is the Gram stain. In 1884 Hans Christian Gram developed the method of staining bacteria to make them more visible and differentiable under a microscope. This
Medical microbiology
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disease. The adjectives "Gram-positive" and "Gram-negative" derive from the surname of Hans Christian Gram, a Danish bacteriologist; as eponymous adjectives, their initial letter can be either capital "G" or lower-case "g", depending on which style guide (e.g., that of the CDC), if any, governs the document being written. This is further explained at "Gram staining § Orthographic note". Gram-negative bacteria Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the gram-staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner
Gram-negative bacteria
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argue that the Archaea and Eukaryotes evolved from gram-positive bacteria. The identification of bacteria in the laboratory is particularly relevant in medicine, where the correct treatment is determined by the bacterial species causing an infection. Consequently, the need to identify human pathogens was a major impetus for the development of techniques to identify bacteria. The "Gram stain", developed in 1884 by Hans Christian Gram, characterises bacteria based on the structural characteristics of their cell walls. The thick layers of peptidoglycan in the "gram-positive" cell wall stain purple, while the thin "gram-negative" cell wall appears pink. By combining morphology and Gram-staining,
Bacteria
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can be definitively classified by this technique. This gives rise to "gram-variable" and "gram-indeterminate" groups. The method is named after its inventor, the Danish scientist Hans Christian Gram (1853–1938), who developed the technique while working with Carl Friedländer in the morgue of the city hospital in Berlin in 1884. Gram devised his technique not for the purpose of distinguishing one type of bacterium from another but to make bacteria more visible in stained sections of lung tissue. He published his method in 1884, and included in his short report the observation that the typhus bacillus did not retain the stain.
Gram stain
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he developed a method for distinguishing between two major classes of bacteria. This technique, the Gram stain, continues to be a standard procedure in medical microbiology. In 1891, Gram taught pharmacology, and later that year was appointed professor at the University of Copenhagen. In 1900, he resigned his chair in pharmacology to become professor of medicine. The work that gained Gram an international reputation was his development of a method of staining bacteria, to make them more visible under a microscope. The stain later played a major role in classifying bacteria. Gram was a modest man, and in his initial
Hans Christian Gram
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stain, Lillie's trichrome, and the Gömöri trichrome stain. Without trichome staining, discerning one feature from another can be extremely difficult. Smooth muscle tissue, for example, is hard to differentiate from collagen. A trichrome stain can colour the muscle tissue red, and the collagen fibres green or blue. Liver biopsies may have fine collagen fibres between the liver cells, and the amount of collagen may be estimated based on the staining method. Trichrome methods are now used for differentiating muscle from collagen, pituitary alpha cells from beta cells, fibrin from collagen, and mitochondria in fresh frozen muscle sections, among other applications.
Trichrome staining
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than to gram-positive bacteria. While this is often true, the classification system breaks down in some cases. A given bacteria's staining result, bacterial membrane organization, and lineage groupings do not always match up. Thus, gram-staining cannot be reliably used to assess familial relationships of bacteria. However, staining often gives reliable information about the composition of the cell membrane, distinguishing between the presence or absence of an outer lipid membrane. Of these two structurally distinct groups of prokaryotic organisms, monoderm prokaryotes are indicated to be ancestral. Based upon a number of different observations including that the gram-positive bacteria are the major
Gram-negative bacteria
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peptidoglycan. Along with cell shape, Gram staining is a rapid method used to differentiate bacterial species. Such staining, together with growth requirement and antibiotic susceptibility testing, and other macroscopic and physiologic tests, forms the full basis for classification and subdivision of the bacteria (e.g., see figure and pre-1990 versions of "Bergey's Manual"). Historically, the kingdom Monera was divided into four divisions based primarily on Gram staining: Firmicutes (positive in staining), Gracilicutes (negative in staining), Mollicutes (neutral in staining) and Mendocutes (variable in staining). Based on 16S ribosomal RNA phylogenetic studies of the late microbiologist Carl Woese and collaborators and colleagues
Gram-positive bacteria
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GC content, but this is lower than that of the Actinobacteria. Although bacteria are traditionally divided into two main groups, gram-positive and gram-negative, based on their Gram stain retention property, this classification system is ambiguous as it refers to three distinct aspects (staining result, envelope organization, taxonomic group), which do not necessarily coalesce for some bacterial species. The gram-positive and gram-negative staining response is also not a reliable characteristic as these two kinds of bacteria do not form phylogenetic coherent groups. However, although Gram staining response is an empirical criterion, its basis lies in the marked differences in the ultrastructure
Gram-positive bacteria
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Paul Ehrlich Paul Ehrlich (; 14 March 1854 – 20 August 1915) was a Nobel prize-winning German-Jewish physician and scientist who worked in the fields of hematology, immunology, and antimicrobial chemotherapy. He is credited with finding a cure for syphilis in 1909. He invented the precursor technique to Gram staining bacteria. The methods he developed for staining tissue made it possible to distinguish between different types of blood cells, which led to the capability to diagnose numerous blood diseases. His laboratory discovered arsphenamine (Salvarsan), the first effective medicinal treatment for syphilis, thereby initiating and also naming the concept of chemotherapy.
Paul Ehrlich
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streaks the material into the 4 quadrants of an agar plate or all over if the colony was singular and did not look mixed. Gram staining the raw sample before incubation or staining freshly grown colony material helps to determine if a colony consists of uniformly appearing bacteria or is mixed, and the color, and shape of bacteria allow a first classification based on morphology. In clinical microbiology numerous other staining techniques for particular organisms are used (acid fast bacterial stain for mycobacteria). Immunological staining techniques, such as direct immunofluorescence have been developed for medically important pathogens that are slow
Isolation (microbiology)
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Gram-negative bacteria Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the gram-staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found everywhere, in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism "Escherichia coli", as well as many pathogenic bacteria, such as "Pseudomonas aeruginosa", "Neisseria gonorrhoeae", "Chlamydia trachomatis", and "Yersinia pestis". They are an important medical challenge, as their outer membrane
Gram-negative bacteria
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of Technology. Neelsen died on April 11, 1898, aged 44, presumably due to pathogen exposure during his many years of bacteriological research. He was known in his time as a recluse who avoided public attention whenever possible, though he was active in the civic affairs of his hometown throughout his life. Together with microbiologist Franz Ziehl, Neelsen developed the Ziehl–Neelsen stain, a method for the staining of acid-fast bacteria, used to this day in the diagnosis of tuberculosis and to detect the presence of other mycobacteria. Friedrich Neelsen Friedrich Carl Adolf Neelsen (29 March 1854, Uetersen - April 11, 1894,
Friedrich Neelsen
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Nissl body A Nissl body, also known as Nissl substance and Nissl material, is a large granular body found in neurons. These granules are of rough endoplasmic reticulum (RER) with rosettes of free ribosomes, and are the site of protein synthesis. It was named after Franz Nissl, a German neuropathologist who invented the Nissl staining method. Nissl bodies can be demonstrated by a method of selective staining developed by Nissl (Nissl staining), using an aniline stain to label extranuclear RNA granules. This staining method is useful to localize the cell body, as it can be seen in the soma and
Nissl body
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the Gram stain. Gram staining uses two dyes: Crystal violet and Fuchsin or Safranin (the counterstain) to differentiate between Gram-positive bacteria (large Peptidoglycan layer on outer surface of cell) and Gram-negative bacteria. Acid-fast Stains are also differential stains. Differential staining Differential Staining is a staining process which uses more than one chemical stain. Using multiple stains can better differentiate between different microorganisms or structures/cellular components of a single organism. Differential staining is used to detect abnormalities in the proportion of different white blood cells in the blood. The process or results are called a WBC differential. This test is useful
Differential staining
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result. Numerous niche applications exploit the intense color of MG. It is used as a biological stain for microscopic analysis of cell biology and tissue samples. In the Gimenez staining method, basic fuchsin stains bacteria red or magenta, and malachite green is used as a blue-green counterstain. Malachite green is also used in endospore staining, since it can directly stain endospores within bacterial cells; here a safranin counterstain is often used. Malachite green can also be used as a saturable absorber in dye lasers, or as a pH indicator between pH 0.2–1.8. However, this use is relatively rare. Leuco-malachite green
Malachite green
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can form spores on aerial hyphae. Actinomycetales bacteria can be infected by bacteriophages, which are called actinophages. Actinomycetales can range from harmless bacteria to pathogens with resistance to antibiotics. Actinomycetales are Gram-positive, but several species have complex cell wall structures that make the Gram staining unsuitable (e.g. Mycobacteriaceae). They are also considered a transitional group between bacteria and fungi because Actinomycetales share characteristics with both these groups. Actinomycetales have prokaryotic nuclei, are susceptible to antibiotics, and have cell walls that contain muramic acid much like bacteria. However, Actinomycetales also form filaments or hyphae, similar to many forms of hyphal fungi.
Actinomycetales
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acids. These acids resist staining by ordinary methods such as a Gram stain. It can also be used to stain a few other bacteria, such as "Nocardia". The reagents used for Ziehl–Neelsen staining are – carbol fuchsin, acid alcohol, and methylene blue. Acid-fast bacilli are bright red after staining. A variation on this staining method is used in mycology to differentially stain acid-fast incrustations in the cuticular hyphae of certain species of fungi in the genus "Russula". It is also useful in the identification of some protozoa, namely Cryptosporidium and Isospora. The Ziehl–Neelsen stain can also hinder diagnosis in the
Ziehl–Neelsen stain
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Dopamine receptor D has been shown to interact with GABRG2. The high degree of homology between D and D receptors and their affinity for drugs with similar pharmacological profile complicate distinguishing between them in research. Antibody staining these two receptors separately is suggested to be inefficient. However, expression of D receptors has been assessed using immunohistochemistry. In this technique, two peptides were obtained from third exracellular loop and third intracellular loop of the receptor, and antisera were developed for staining the receptor in frozen mouse brain tissue. A method involving mRNA probes for in situ hybridization has been developed, which
Dopamine receptor D5
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variables can influence the colour intensity and every protein has its own staining characteristics; clean glassware, pure reagents and water of highest purity are the key points to successful staining. Silver staining was developed in the 14th century for colouring the surface of glass. It has been used extensively for this purpose since the 16th century. The colour produced by the early silver stains ranged between light yellow and an orange-red. Camillo Golgi perfected the silver staining for the study of the nervous system. Golgi's method stains a limited number of cells at random in their entirety. Autoradiography, also used
Polyacrylamide gel electrophoresis
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stains "certified" by themselves rather than by the Biological Stain Commission. Such products may or may not be suitable for diagnostic and other applications. A simple staining method for bacteria that is usually successful, even when the "positive staining" methods detailed below fail, is to use a negative stain. This can be achieved by smearing the sample onto the slide and then applying nigrosin (a black synthetic dye) or India ink (an aqueous suspension of carbon particles). After drying, the microorganisms may be viewed in bright field microscopy as lighter inclusions well-contrasted against the dark environment surrounding them. Note: negative
Staining
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Moeller stain Moeller staining involves the use of a steamed dye reagent in order to increase the stainability of endospores; carbol fuchsin is the primary stain used in this method. Endospores are stained red, while the counterstain methylene blue stains the vegetative bacteria blue. Endospores are surrounded by a highly resistant spore coat, which is highly resistant to excessive heat, freezing, desiccation, as well as chemical agents. More importantly, for identification, spores are resistant to commonly employed staining techniques; therefore alternative staining methods are required. Carbol fuchsin is applied to a heat-fixed slide. The slide is then heated over a
Moeller stain
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Gram, but are derived from such forms. Some bacteria have cell walls which are particularly adept at retaining stains. These will appear positive by Gram stain even though they are not closely related to other gram-positive bacteria. These are called acid fast bacteria, and can only be differentiated from other gram-positive bacteria by special staining procedures. Gram-negative bacteria generally possess a thin layer of peptidoglycan between two membranes ("diderms"). Most bacterial phyla are gram-negative, including the cyanobacteria, green sulfur bacteria, and most Proteobacteria (exceptions being some members of the "Rickettsiales" and the insect-endosymbionts of the "Enterobacteriales"). Some bacteria, after staining
Gram stain
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bacillus (plural bacilli) is a rod-shaped bacterium. Although "Bacillus", capitalized and italicized, specifically refers to the genus, the word bacillus (plural "bacilli") may also be used to describe any rod-shaped bacterium, and in this sense, bacilli are found in many different taxonomic groups of bacteria. There is no connection between the shape of a bacterium and its colors in the Gram staining. Bacilli usually divide in the same plane and are solitary, but can combine to form diplobacilli, streptobacilli, and palisades. Spiral bacteria form the third major bacterial cell morphology. Spiral bacteria can be sub-classified as spirilla, spirochetes, or vibrios
Bacterial cellular morphologies
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still treat them as a monophyletic taxon (though not a clade; his definition of monophyly requires a single common ancestor but does not require holophyly, the property that all descendants be encompassed by the taxon) and refer to the group as a subkingdom "Negibacteria". Bacteria are traditionally divided into the two groups: gram-positive and gram-negative, based on their gram-staining response. Gram-positive bacteria are also referred to as "monoderms" having one membrane, and gram-negative bacteria are also referred to as "diderms", having two membranes. These groups are often thought of as lineages, with gram-negative bacteria more closely related to one another
Gram-negative bacteria
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as Giemsa stain or crystal violet allows a microscopist to describe its size, shape, internal and external components and its associations with other cells. The response of bacteria to different staining procedures is used in the taxonomic classification of microbes as well. Two methods, the Gram stain and the acid-fast stain, are the standard approaches used to classify bacteria and to diagnosis of disease. The Gram stain identifies the bacterial groups Firmicutes and Actinobacteria, both of which contain many significant human pathogens. The acid-fast staining procedure identifies the Actinobacterial genera "Mycobacterium" and "Nocardia". Biochemical tests used in the identification of
Infection
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the acid-fast species are stained bright red and stand out clearly against a blue background. Another method is the Kinyoun method, in which the bacteria are stained bright red and stand out clearly against a green background. Acid-fast "Mycobacteria" can also be visualized by fluorescence microscopy using specific fluorescent dyes (auramine-rhodamine stain, for example). The eggs of the parasitic lung fluke "Paragonimus westermani" are actually destroyed by the stain, which can hinder diagnosis in patients who present with TB-like symptoms. Very few structures are acid-fast; this makes staining for acid-fastness particularly useful in diagnosis. The following are notable examples of
Acid-fastness
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Endospore staining Endospore Staining is a technique used in bacteriology to identify the presence of endospores in a bacterial sample, which can be useful for classifying bacteria. Within bacteria, endospores are protective structures used to survive extreme conditions, but this protective nature makes them difficult to stain using normal techniques such as and Gram staining. Special techniques for endospore staining include the Schaeffer–Fulton stain and the Moeller stain. The primary dye for endospore staining is malachite green. It takes a long time for the spores to stain due to their density, so time acts as the mordant when performing this
Endospore staining
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Nocht at the "Institut für Tropenmedizin" in Hamburg, where in 1900 he became head of the Department of Chemistry. In 1904 Giemsa published an essay on the staining procedure for flagellates, blood cells, and bacteria. Giemsa improved the Romanowsky stain (Eosin Y and Methylene Blue) by stabilizing this dye solution with glycerol. This allowed for reproducible staining of cells for microscopy purposes. This method is still used in laboratories today. In 1933 Giemsa signed the "Loyalty Oath of German Professors to Adolf Hitler and the National Socialist State". He also joined the NSDAP. Gustav Giemsa Gustav Giemsa (; November 20,
Gustav Giemsa
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different scatter signals upon flow cytometric analysis. This further helps in their differentiation. Quantification of prochlorococcus is considered a major breakthrough as it has almost only been possible through flow cytometry. This is due to the inability of epifluorescence microscopy to detect the low chlorophyll autofluorescence present in prochlorococcus. Besides photosynthetic bacterioplankton, non-photosynthetic bacterioplankton can also be enumerated by flow cytometry. This is done via DNA or food vacuole staining. Flow cytometry has especially been successful at differentiating prochloroccocus from heterotrophic bacteria, who's counts were initially confounded due to their similar size. Use of epifluorescence microscopy over flow cytometry in
Bacterioplankton counting methods
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for the staining pattern of poor absorption followed by high retention. The most common staining technique used to identify acid-fast bacteria is the Ziehl-Neelsen stain or acid-fast stain, in which the acid fast bacilli are stained bright red and stand out clearly against a blue background. The obligate intracellular bacteria in family Chlamydiaceae are unique in their morphology as they do not contain detectable amounts of peptidoglycans. However, the extracellular forms of these gram-negative bacteria maintain their structural integrity because of a layer of disulfide bind cross-linked layer of cysteine-rich proteins, which is located between cytoplasmic membrane and outer membrane
Cell envelope
167593
Gram staining is a bacteriological laboratory technique used to differentiate bacterial species into two large groups (gram-positive and gram-negative) based on the physical properties of their cell walls. Gram staining is not used to classify archaea, formerly archaeabacteria, since these microorganisms yield widely varying responses that do not follow their phylogenetic groups. The Gram stain is not an infallible tool for diagnosis, identification, or phylogeny, and it is of extremely limited use in environmental microbiology. It is used mainly to make a preliminary morphologic identification or to establish that there are significant numbers of bacteria in a clinical specimen. It
Gram stain
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stain, particularly in Gram staining for classifying bacteria. When conducting DNA gel electrophoresis, crystal violet can be used as a nontoxic DNA stain as an alternative to fluorescent, intercalating dyes such as ethidium bromide. Used in this manner, it may be either incorporated into the agarose gel or applied after the electrophoresis process is finished. Used at a 0.001% concentration and allowed to stain a gel after electrophoresis for 30 minutes, it can detect as little as 16 ng of DNA. Through use of a methyl orange counterstain and a more complex staining method, sensitivity can be improved further to
Crystal violet
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staining is a mild technique that may not destroy the microorganisms, and is therefore unsuitable for studying pathogens. Gram staining is used to determine gram status to classify bacteria broadly. It is based on the composition of their cell wall. Gram staining uses crystal violet to stain cell walls, iodine as a mordant, and a fuchsin or safranin counterstain to mark all bacteria. Gram status is important in medicine; the presence or absence of a cell wall changes the bacterium's susceptibility to some antibiotics. Gram-positive bacteria stain dark blue or violet. Their cell wall is typically rich with peptidoglycan and
Staining
6898708
In 1884 he was appointed professor of pathological anatomy at the Senkenbergsche Stiftung in Frankfurt am Main, and received the title of "Geheimer Medizinal-Rat" in 1899. Weigert assisted Cohnheim in many of his researches, and wrote much on the staining of bacteria in microscopy. In 1884 he introduced a precise method for staining myelin sheaths. He is credited with the discovery of vascular tuberculosis, and was the first to demonstrate how tuberculous material could enter the bloodstream. He contributed many essays to medical journals. Among his works are: Karl Weigert Karl Weigert, Carl Weigert (19 March 1845 in Münsterberg in
Karl Weigert
7850463
as epifluorescence microscopy, the assessment of sperm chromatin quality. Acridine orange stain is particularly useful in the rapid screening of normally sterile specimens, and its recommended for the use of fluorescent microscopic detection of microorganisms in direct smears prepared from clinical and non-clinical materials. The staining has to be performed at an acid pH in order to obtain this differential staining effect with bacteria showing orange stain and tissue components yellow to green. Acridine orange is a versatile fluorescence dye used to stain acidic vacuoles (lysosomes, endosomes, and autophagosomes), RNA, and DNA in living cells. This method is a cheap
Acridine orange
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method. The results showed that erythrasma was more prevalent in males who were over the age of 40 years. Their conclusions were that erythrasma is a common condition and can also easily mimic other infections such as tinea pedis and that gram staining is a better tool to differentiate the bacteria and it's mechanism than the Wood's lamp method. Erythrasma Erythrasma is a superficial skin infection that causes brown, scaly skin patches. It is caused by "Corynebacterium minutissimum," a normal part of skin flora (the microorganisms that are normally present on the skin). There are two types of erythrasma: generalized
Erythrasma
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be performed on tissue, the recommended fixative is 10% neutral-buffered formalin or Bouin solution. For blood smears, the recommended fixative is methanol. Glutaraldehyde is not recommended because free aldehyde groups may be available to react with the Schiff reagent, which may result in false positive staining. Periodic acid–Schiff stain Periodic acid–Schiff (PAS) is a staining method used to detect polysaccharides such as glycogen, and mucosubstances such as glycoproteins, glycolipids and mucins in tissues. The reaction of periodic acid oxidizes the vicinal diols in these sugars, usually breaking up the bond between two adjacent carbons not involved in the glycosidic linkage
Periodic acid–Schiff stain
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cannot identify bacteria to the species level, and for most medical conditions, it should not be used as the sole method of bacterial identification. In clinical microbiology laboratories, it is used in combination with other traditional and molecular techniques to identify bacteria. Some organisms are gram-variable (meaning they may stain either negative or positive); some are not stained with either dye used in the Gram technique and are not seen. In a modern environmental or molecular microbiology lab, most identification is done using genetic sequences and other molecular techniques, which are far more specific and informative than differential staining. Gram
Gram stain
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is strictly caused by atypical bacteria, for this disease can also have a fungal, protozoan or viral cause. Atypical bacteria Atypical bacteria are bacteria that do not color with gram-staining but rather remain colorless: they are neither Gram-positive nor Gram-negative. These include the Chlamydiaceae, Legionella and the Mycoplasmataceae (including mycoplasma and ureaplasma); the Rickettsiaceae are also often considered atypical. Gram-positive bacteria have a thick peptidoglycan layer in their cell wall, which retains the crystal violet during Gram staining, resulting in a purple color. Gram-negative bacteria have a thin peptidoglycan layer which does not retain the crystal violet, so when safranin
Atypical bacteria
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it does not produce any endospores. This is due to its waxy cell wall which retains the malachite green dye even after the decolorizing process. A different type of staining called acid-fast stain will have to be done in order to get further information about this particular type of bacterium. Endospore staining Endospore Staining is a technique used in bacteriology to identify the presence of endospores in a bacterial sample, which can be useful for classifying bacteria. Within bacteria, endospores are protective structures used to survive extreme conditions, but this protective nature makes them difficult to stain using normal techniques
Endospore staining
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bunsen burner, or suspended over a hot water bath, covered with a paper towel, and steamed for 3 minutes. The slide is rinsed with acidified ethanol, and counter-stained with Methylene blue. An improved method involves the addition of the surfactant Tergitol 7 to the carbol fuchsin stain, and the omission of the steaming step. Moeller stain Moeller staining involves the use of a steamed dye reagent in order to increase the stainability of endospores; carbol fuchsin is the primary stain used in this method. Endospores are stained red, while the counterstain methylene blue stains the vegetative bacteria blue. Endospores are
Moeller stain
2974046
aspects (staining result, cell-envelope organization, taxonomic group), which do not necessarily coalesce for some bacterial species. However, although Gram-staining response of bacteria is an empirical criterion, its basis lies in the marked differences in the ultrastructure and chemical composition of the two main kinds of bacteria. These bacteria are distinguished from each other based on the presence or absence of an outer lipid membrane, which is a more reliable and fundamental characteristic of the bacterial cells. All gram-positive bacteria are bounded by a single unit lipid membrane; they generally contain a thick layer (20-80 nm) of peptidoglycan responsible for retaining
Periplasm
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is the use of silver to stain histologic sections. This kind of staining is important especially to show proteins (for example type III collagen) and DNA. It is used to show both substances inside and outside cells. Silver staining is also used in temperature gradient gel electrophoresis. Some cells are "argentaffin". These reduce silver solution to metallic silver after formalin fixation. This method was discovered by Italian Camillo Golgi, by using a reaction between silver nitrate and potassium dichromate, thus precipitating silver chromate in some cells (see Golgi's method). Other cells are "argyrophilic". These reduce silver solution to metallic silver
Staining
14745613
Atypical bacteria Atypical bacteria are bacteria that do not color with gram-staining but rather remain colorless: they are neither Gram-positive nor Gram-negative. These include the Chlamydiaceae, Legionella and the Mycoplasmataceae (including mycoplasma and ureaplasma); the Rickettsiaceae are also often considered atypical. Gram-positive bacteria have a thick peptidoglycan layer in their cell wall, which retains the crystal violet during Gram staining, resulting in a purple color. Gram-negative bacteria have a thin peptidoglycan layer which does not retain the crystal violet, so when safranin is added during the process, they stain red. The Chlamydiaceae and Mycoplasmataceae lack a peptidoglycan layer so do
Atypical bacteria
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responsible vesicular transport during synthesis and sorting of proteins. He gave this functional organisation an acronym GERL, for "G"olgi-"e"ndoplasmic "r"eticulum-"l"ysosome. Novikoff's further works became a milestone in understanding the importance of autophagy in diseases such as cancer. He was the first to establish the type of liver tumour, now known in his honour as "Novikoff hepatoma". In 1961 with Sidney Goldfischer, Novikoff developed a staining method for the Golgi body using the enzyme nucleosidediphosphatase, by which they described the enzymatic property of the organelle for the first time. In 1969 they developed a staining technique (alkaline diaminobenzidine, or DAB) by
Alex B. Novikoff
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called rods when the bacteriologic context is clear. Sea Bacilli usually divide in the same plane and are solitary, but can combine to form diplobacilli, streptobacilli, and palisades. There is no connection between the shape of a bacterium and its color in the Gram staining. MacConkey agar can be used to distinguish among Gram negative bacilli such as "E. coli" and salmonella. Bacillus (shape) A bacillus (plural bacilli) or bacilliform bacterium is a rod-shaped bacterium or archaeon. Bacilli are found in many different taxonomic groups of bacteria. However, the name "Bacillus", capitalized and italicized, refers to a specific genus of
Bacillus (shape)
13386864
teeth. In some species, this toothpad is made up of a large patch with several rows in a large cluster. In other species of "Syndontis", this toothpad is clearly divided into two separate groups, separated by a thin band of skin that divides the toothpad. This character is used as a method of differentiating between two different but similar species of "Syndontis". In "S. tanganyicae", the toothpad is interrupted, with a distinct gap between groups of teeth. On the lower jaw, or mandible, the teeth of "Syndontis" are attached to flexible, stalk-like structures and described as "s-shaped" or "hooked". The
Synodontis tanganyicae
18087186
with several rows in a large cluster. In other species of "Syndontis", this toothpad is clearly divided into two separate groups, separated by a thin band of skin that divides the toothpad. This character is used as a method of differentiating between two different but similar species of "Syndontis". In "S. irsacae", the toothpad is interrupted, or separated into two distinct groups. On the lower jaw, or mandible, the teeth of "Syndontis" are attached to flexible, stalk-like structures and described as "s-shaped" or "hooked". The number of teeth on the mandible is used to differentiate between species; in "S. irsacae",
Synodontis irsacae
18085563
in a large cluster. In other species of "Syndontis", this toothpad is clearly divided into two separate groups, separated by a thin band of skin that divides the toothpad. This character is used as a method of differentiating between two different but similar species of "Syndontis". In "S. melanostictus", the toothpad is interrupted, or separated into two distinct groups. On the lower jaw, or mandible, the teeth of "Syndontis" are attached to flexible, stalk-like structures and described as "s-shaped" or "hooked". The number of teeth on the mandible is used to differentiate between species; in "S. melanostictus", there are 23
Synodontis melanostictus
4264236
for the staining pattern of poor absorption followed by high retention. Some bacteria may also be partially acid-fast, such as Nocardia. Acid-fast organisms are difficult to characterize using standard microbiological techniques, though they can be stained using concentrated dyes, particularly when the staining process is combined with heat. Some, such as "Mycobacteria", can be stained with the Gram stain, but they do not take the crystal violet well and thus appear light purple, which can still potentially result in an incorrect gram positive identification. The most common staining technique used to identify acid-fast bacteria is the Ziehl-Neelsen stain, in which
Acid-fastness
19524537
dead bacteria. Its efficiency is directly related to the increase in temperature and can last for hours, being a much faster method than direct bioreduction. It occurs through the formation of slimes and capsules, and with a preference for binding to the phosphate and phosphoryl groups (although it also occurs with carboxyl, amine or sulfhydryl groups). "Firmicutes" and other bacteria like "Citrobacter freudii" have significant biosorption capabilities; "Citrobacter" does it through electrostatic interaction of uranium with phosphates of their LPS. Quantitative analyzes determine that, in the case of uranium, biosorption may vary within a range between 45 and 615 milligrams
Bioremediation of radioactive waste
6216098
Carbol fuchsin Carbol fuchsin, carbol-fuchsin, or carbolfuchsin, is a mixture of phenol and basic fuchsin, used in bacterial staining procedures. It is commonly used in the staining of mycobacteria as it has an affinity for the mycolic acids found in their cell membranes. It is a component of Ziehl–Neelsen stain, a differential stain. Carbol fuchsin is used as the primary stain dye to detect acid-fast bacteria because it is more soluble in the cells wall lipids than in the acid alcohol. If the bacteria is acid-fast the bacteria will retain the initial red color of the dye because they are
Carbol fuchsin
2455119
lacks the secondary membrane and lipopolysaccharide layer found in Gram-negative bacteria. On most Gram-stained preparations, Gram-negative organisms appear red or pink because they are counterstained. Because of presence of higher lipid content, after alcohol-treatment, the porosity of the cell wall increases, hence the CVI complex (crystal violet – iodine) can pass through. Thus, the primary stain is not retained. Also, in contrast to most Gram-positive bacteria, Gram-negative bacteria have only a few layers of peptidoglycan and a secondary cell membrane made primarily of lipopolysaccharide. Endospore staining is used to identify the presence or absence of endospores, which make bacteria very
Staining
167621
cephalosporins, beta-lactam-betalactamase combinations (e.g. pipercillin-tazobactam), Folate antagonists, quinolones, and carbapenems. Many of these antibiotics also cover gram positive organisms. The drugs that specifically target gram negative organisms include aminoglycosides, monobactams (aztreonam) and Ciprofloxacin. Gram-negative bacteria display : Along with cell shape, gram-staining is a rapid diagnostic tool and once was used to group species at the subdivision of Bacteria. Historically, the kingdom Monera was divided into four divisions based on gram-staining: Firmacutes (+), Gracillicutes (−), Mollicutes (0) and Mendocutes (var.). Since 1987, the monophyly of the gram-negative bacteria has been disproven with molecular studies. However some authors, such as Cavalier-Smith
Gram-negative bacteria
3356929
load as before is also measure by PCR. Tissue staining using a monoclonal antibody against MCV T antigen shows utility in differentiating Merkel cell carcinoma from other small, round cell tumors. Blood tests to detect MCV antibodies have been developed and show that infection with the virus is widespread although Merkel cell carcinoma patients have exceptionally higher antibody responses than asymptomatically infected persons. Murine polyomavirus was the first polyomavirus discovered, having been reported by Ludwik Gross in 1953 as an extract of mouse leukemias capable of inducing parotid gland tumors. The causative agent was identified as a virus by Sarah
Polyomaviridae
2455120
difficult to kill. This is particularly useful for identifying endospore-forming bacterial pathogens such as "Clostridium difficile". Ziehl-Neelsen staining is used to stain species of "Mycobacterium tuberculosis" that do not stain with the standard laboratory staining procedures such as Gram staining. The stains used are the red coloured Carbol fuchsin that stains the bacteria and a counter stain such as Methylene blue Haematoxylin and eosin staining protocol is used frequently in histology to examine thin sections of tissue. Haematoxylin stains cell nuclei blue, while eosin stains cytoplasm, connective tissue and other extracellular substances pink or red. Eosin is strongly absorbed by
Staining
689361
strains and by the method of separating mixtures of organisms on plates of nutrient media. Between 1880 and 1881 Pasteur produced two successful vaccinations for animals against diseases caused by bacteria and it was successful. The importance of bacteria was recognized as it led to a study of disease prevention and treatment of diseases by vaccines. Bacteriology has developed and can be studied in agriculture, marine biology, water pollution, bacterial genetics and biotechnology. Bacteriology Bacteriology is the branch and specialty of biology that studies the morphology, ecology, genetics and biochemistry of bacteria as well as many other aspects related to
Bacteriology
16470904
bacteria have the largest genomes out of the three types of bacteria; however, they have fewer pseudogenes than bacteria that have recently acquired pathogenicity. Facultative and recently evolved pathogenic bacteria exhibit a smaller genome size than free-living bacteria, yet they have more pseudogenes than any other form of bacteria. Obligate bacterial symbionts or pathogens have the smallest genomes and the fewest pseudogenes of the three groups. The relationship between life-styles of bacteria and genome size raises questions as to the mechanisms of bacterial genome evolution. Researchers have developed several theories to explain the patterns of genome size evolution amongst bacteria.
Bacterial genome
94225
Proto-Indo-European a contrast between the dative case and the accusative case, which English has lost. However, this similarity between German and Russian is not evidence that German is more closely related to Russian than to English; it only means that the "innovation" in question—the loss of the accusative/dative distinction—happened more recently in English than the divergence of English from German. The division of related languages into sub-groups is more certainly accomplished by finding "shared linguistic innovations" differentiating them from the parent language, rather than shared features retained from the parent language. Languages have been compared since antiquity. For example, in
Comparative method
6579591
Neutral red Neutral red (toluylene red, Basic Red 5, or C.I. 50040) is a eurhodin dye used for staining in histology. It stains lysosomes red. It is used as a general stain in histology, as a counterstain in combination with other dyes, and for many staining methods. Together with Janus Green B, it is used to stain embryonal tissues and supravital staining of blood. Can be used for staining Golgi apparatus in cells and Nissl granules in neurons. In microbiology, it is used in the MacConkey agar to differentiate bacteria for lactose fermentation. Neutral red can be used as a
Neutral red
3074879
Golgi's method Golgi's method is a silver staining technique that is used to visualize nervous tissue under light microscopy. The method was discovered by Camillo Golgi, an Italian physician and scientist, who published the first picture made with the technique in 1873. It was initially named the black reaction ("la reazione nera") by Golgi, but it became better known as the Golgi stain or later, Golgi method. Golgi staining was used by Spanish neuroanatomist Santiago Ramón y Cajal (1852–1934) to discover a number of novel facts about the organization of the nervous system, inspiring the birth of the neuron doctrine.
Golgi's method
18573742
Ginger Krieg Dosier Ginger Krieg Dosier is an American architect who, in 2010, developed a technique for using microbiologically induced calcite precipitation to manufacture bricks for construction. Dosier's brick-making method consists of filling a rectangular form with sand layered intermittently with a solution containing urea, calcium chloride, and the non-pathogenic bacteria Sporosarcina pasteurii. After several days, the bacteria create a chemical chain reaction producing a mineral that binds the sand together into a brick. Because this process does not involve firing the brick in a kiln as in conventional brick-making, Dosier estimates that her method could reduce carbon emissions by
Ginger Krieg Dosier
11603631
thin band of skin that divides the toothpad. This character is used as a method of differentiating between to different but similar species of "Syndontis". In "S. petricola", the toothpad is interrupted, or clearly divided between the groups of teeth on the toothpad. On the lower jaw, or mandible, the teeth of "Syndontis" are attached to flexible, stalk-like structures and described as "s-shaped" or "hooked". The number of teeth on the mandible is used to differentiate between species; in "S. petricola", there are 31 to 50 teeth on the mandible, arranged in a six short rows. Some of the species
Synodontis petricola
4522378
Prokaryotic names with Standing in Nomenclature (LPSN) Thermotogae The Thermotogae are a phylum of the domain Bacteria. The phylum Thermotogae is composed of Gram-negative staining, anaerobic, and mostly thermophilic and hyperthermophilic bacteria. The name of this phylum is derived from the existence of many of these organisms at high temperatures along with the characteristic sheath structure, or "toga", surrounding the cells of these species. Recently, some Thermotogae existing at moderate temperatures have also been identified. Although Thermotogae species exhibit Gram-negative staining, they are bounded by a single-unit lipid membrane, hence they are monoderm bacteria. Because of the ability of some
Thermotogae
4522372
Thermotogae The Thermotogae are a phylum of the domain Bacteria. The phylum Thermotogae is composed of Gram-negative staining, anaerobic, and mostly thermophilic and hyperthermophilic bacteria. The name of this phylum is derived from the existence of many of these organisms at high temperatures along with the characteristic sheath structure, or "toga", surrounding the cells of these species. Recently, some Thermotogae existing at moderate temperatures have also been identified. Although Thermotogae species exhibit Gram-negative staining, they are bounded by a single-unit lipid membrane, hence they are monoderm bacteria. Because of the ability of some Thermotogae species to thrive at high temperatures,
Thermotogae
3819814
of increasing concentrations (e.g., 50%, 75%, 90%, 95%, 100%), and cleared using a detergent like xylene before being imaged under a microscope. Depending on the method of fixation and tissue preservation, the sample may require additional steps to make the epitopes available for antibody binding, including deparaffinization and antigen retrieval. For formalin-fixed paraffin-embedded tissues, antigen-retrieval is often necessary, and involves pre-treating the sections with heat or protease. These steps may make the difference between the target antigens staining or not staining. Depending on the tissue type and the method of antigen detection, endogenous biotin or enzymes may need to be
Immunohistochemistry
14351050
and diagnosing infectious diseases in a rapid manner within the clinic. Combined with traditional gram staining of positive blood cultures, PNAs can be used to target species-specific rRNA (ribosomal RNA) to identify different strains of bacteria or yeast. Since the test can be performed relatively quickly, the test is being considered for use in hospitals where hospital-acquired infections can occur. Another adaptation that utilizes PNAs and FISH is known as CO-FISH (Chromosome Orientation-FISH) which allows for the labelling of chromosomes with PNAs in a strand specific manner. This method involves the selective removal of newly replicated strands of DNA (through
Q-FISH
16986323
Penfield helped explain oligodendroglia. whilst Rio Hortega discovered microglia. which are the cells that protect the brain from infection. He managed to identify microglia between 1919 and 1921 by staining the cells with silver carbonate. His method of staining also led to the discovery of oligodendroglia in 1921, which both he and Penfield are now credited with. However it was Rio Hortega who named the cells. His discoveries in 1920 created issues with Ramón y Cajal, who led the lab, as he had earlier won the Nobel prize. By 1931 del Río Hortega was leading Spain's cancer institute, but he
Pío del Río Hortega
12220522
liquid do not match. These colors are basically the same as the colors seen when using darkfield dispersion staining. The double aperturing of this method enhances the color effect but also sacrifices resolution of the particles. In fields of view where particles may be stacked or in very close proximity it may be difficult to be sure which small particle is actually producing the color. Examples of this type of dispersion staining and the colors shown for different λo’s can be seen at the microlabgallery.com site for Objective Stop Dispersion Staining. This method is more difficult to interpret due to
Dispersion staining
43642
made up of cellulose, fungi cell walls are made up of chitin and bacteria cell walls are made up of peptidoglycan. A gelatinous capsule is present in some bacteria outside the cell membrane and cell wall. The capsule may be polysaccharide as in pneumococci, meningococci or polypeptide as "Bacillus anthracis" or hyaluronic acid as in streptococci. Capsules are not marked by normal staining protocols and can be detected by India ink or methyl blue; which allows for higher contrast between the cells for observation. Flagella are organelles for cellular mobility. The bacterial flagellum stretches from cytoplasm through the cell membrane(s)
Cell (biology)
19278181
growing (Auramine-rhodamine stain for mycobacteria) or difficult to grow (such as Legionella pneumophila species) and where the test result would alter standard management and empirical therapy. Biochemical testing of bacteria involves a set of agars in vials to separate motile from non-motile bacteria. In 1970 a miniaturized version was developed, called the analytical profile index. Successful identification via e.g. genome sequencing and genomics depends on pure cultures. While the most rapid method to identify bacteria is by sequencing their 16S rRNA gene, which has been PCR-amplified beforehand, this does method not require isolation. Since most bacteria cannot be grown with
Isolation (microbiology)
7919779
Sister chromatid exchange Sister chromatid exchange (SCE) is the exchange of genetic material between two identical sister chromatids. It was first discovered by using the Giemsa staining method on one chromatid belonging to the sister chromatid complex before anaphase in mitosis. The staining revealed that few segments were passed to the sister chromatid which were not dyed. The Giemsa staining was able to stain due to the presence of bromodeoxyuridine analogous base which was introduced to the desired chromatid. The reason for the (SCE) is not known but it is required and used as a mutagenic testing of many products.
Sister chromatid exchange
9698308
series, and the Illusive Man from the Mass Effect series of videogames. Tricorder The Lab-On-a-Chip Application Development Portable Test System (LOCAD-PTS) used by astronauts on the International Space Station is designed specifically to biochemical molecules with the purpose of "identifying microbes on space station services" through use of the Gram Staining Method. Though less advanced than the fictional tricorder of the "Star Trek" series, the LOCAD-PTS is useful for quickly identifying bacteria and fungi on the International Space Station without having to send samples back to Earth, thus risking contamination or degradation. Fungi have proven to be a hazard if
Technology in science fiction
14287226
described ("Bacillus schlegelii"). In addition, "H. thermophilus" has both morphological and physiological differences that vary from processes in "B. schegelii", suggesting there are multiple means for being viable in different environments. Until the discovery of "H. thermophilus", it was thought that no obligate chemolithotrophic hydrogen oxidizing bacteria existed. "Hydrogenobacter thermophilus" is a straight rod (bacillus) bacterium and an extreme thermophile. The size is about .3-.5 microns in width and 2-3 microns in length. Gram staining was done using a Hucker Modification and the reaction was found to be Gram negative. Motility and sporulation were tested using hanging cell method and
Hydrogenobacter thermophilus
13386392
that divides the toothpad. This character is used as a method of differentiating between two different but similar species of "Syndontis". In "S. lucipinnis", the toothpad is interrupted, or separated into two distinct groups. On the lower jaw, or mandible, the teeth of "Syndontis" are attached to flexible, stalk-like structures and described as "s-shaped" or "hooked". The number of teeth on the mandible is used to differentiate between species; in "S. lucipinnis", there are 35 to 51 teeth on the mandible, arranged in six short rows. Some of the species of "Synodontis" have an opening or series of openings called
Synodontis lucipinnis
2976404
(with a few exceptions e.g. intracellular parasites such as "Mycoplasma") contain peptidoglycan, not all cell walls have the same overall structures. This is notably expressed through the classification into gram positive and gram negative bacteria. The gram-positive cell wall is characterised by the presence of a very thick peptidoglycan layer, which is responsible for the retention of the crystal violet dyes during the Gram staining procedure. It is found exclusively in organisms belonging to the Actinobacteria (or high %G+C gram-positive organisms) and the Firmicutes (or low %G+C gram-positive organisms). Bacteria within the Deinococcus-Thermus group may also exhibit gram-positive staining behaviour
Cell envelope
2218986
The molecular mechanism and reason for these patterns is unknown, although it likely related to replication timing and chromatin packing. Several chromosome-banding techniques are used in cytogenetics laboratories. Quinacrine banding (Q-banding) was the first staining method used to produce specific banding patterns. This method requires a fluorescence microscope and is no longer as widely used as Giemsa banding (G-banding). Reverse banding, or R-banding, requires heat treatment and reverses the usual black-and-white pattern that is seen in G-bands and Q-bands. This method is particularly helpful for staining the distal ends of chromosomes. Other staining techniques include C-banding and nucleolar organizing region
Cytogenetics
11899647
Dmitri Leonidovich Romanowsky independently developed techniques using a mixture of Eosin Y and modified methylene blue (methylene azure) that produced a surprising hue unattributable to either staining component: a shade of purple. Malachowski used alkali-treated methylene blue solutions and Romanowsky used methylene blue solutions which were molded or aged. This new method differentiated blood cells and demonstrated the nuclei of malarial parasites. Malachowski's staining technique was one of the most significant technical advances in the history of malaria. In 1891, Paul Guttmann and Ehrlich noted that methylene blue had a high affinity for some tissues and that this dye had
History of malaria
7327401
off light when mixed with ATP (adenosine triphosphate), an energy storage compound found in all living cells, to detect the presence of ATP. This method for ATP detection can be used to detect life on other planets as well as microbiological organisms. Chappelle also proved that the number of bacteria in water can be measured by the amount of light given off by that bacteria. This discovery allowed scientists and doctors to detect small amounts of bacteria in places such as urine, in order to detect an onset of a bacterial infection. Additionally, he developed a method for determining vegetation
Emmett Chappelle
12012718
enzyme for transferring electrons to oxygen. If the culture is determined to be oxidase positive, alternative tests must be carried out to correctly identify the bacterial species. API stands for Analytical Profile Index and is a commercial system to identify different bacteria. One of the API systems is specific for differentiating between members of the Gram negative bacterial Family Enterobacteriaceae and is called API-20E. The other API system is specific for Gram positive bacteria, including Staphylococcus species, Micrococcus, species, and related organisms, and is called API-Staph. API test strips consists of wells containing dehydrated substrates to detect enzymatic activity, usually
Analytical profile index
106719
describe the gaps or nodes found on axons and for this contribution these axonal features are now commonly referred to as the Nodes of Ranvier. Santiago Ramón y Cajal, a Spanish anatomist, proposed that axons were the output components of neurons. He also proposed that neurons were discrete cells that communicated with each other via specialized junctions, or spaces, between cells, now known as a synapse. Ramón y Cajal improved a silver staining process known as Golgi's method, which had been developed by his rival, Camillo Golgi. During the development of dendrites, several factors can influence differentiation. These include modulation
Dendrite
12220532
Christiansen effect and the dispersion staining methods. Brown, K. M. and W. C. McCrone, “Dispersion Staining”, THE MICROSCOPE, Vol. 13, pp. 311 and Vol. 14, pp. 39, 1963. Cherkasov, Yu. A., “Application of ‘Focal Screening’ to Measurements of Indices of Refraction by the Immersion Method”, Trans. by Ivan Mittin, INTERNATIONAL GEOLOGICAL REVIEW, vol. 2, pp. 218–235, 1960. Crossmon, G. C. “Microscopical Distribution of Corundum Among its Natural and Artificial Associates”, ANALYTICAL CHEMISTRY, Vol. 20, No. 10, 1948. Crossmon, G. C., “The ‘Dispersion Staining’ method for the selective coloration of tissue.” STAIN TECHNOLOGY, Vol. 24, pp. 61-65, 1949. Crossmon, G. C.,
Dispersion staining
14287229
ribosomal RNA gene in "H. thermophilus" also suggest that they are part of some of the earliest differentiating orders of bacteria termed the Aquificales. As a result of the early branch point in Aquificales’ genetic history, it indicates that the characteristics of the last common ancestor of life were possibly thermophilic and fixed carbon chemoautotrophically; this gives some direction to the evolution of life. In 2010, the entire genome of "Hydrogenobacter thermophilus" TK-6 was sequenced by Hiroyuki Arai et al. Sequencing was done via whole genome shotgun approach through the Sanger sequencing method, and assembled via the Paracel Genome Assembler.
Hydrogenobacter thermophilus
261992
microscopy in biology. During the last decades of the 20th century, particularly in the post-genomic era, many techniques for fluorescent staining of cellular structures were developed. The main groups of techniques involve targeted chemical staining of particular cell structures, for example, the chemical compound DAPI to label DNA, use of antibodies conjugated to fluorescent reporters, see immunofluorescence, and fluorescent proteins, such as green fluorescent protein. These techniques use these different fluorophores for analysis of cell structure at a molecular level in both live and fixed samples. The rise of fluorescence microscopy drove the development of a major modern microscope design,
Microscope
1873211
who sings the lead vocal (as The Alan Parsons Project's Eric Woolfson often did). For classical and jazz recordings, particularly instrumentals where multitracking is chosen as the recording method (as opposed to direct to stereo, for example), a different arrangement is used; all tracks are recorded simultaneously. Sound barriers are often placed between different groups within the orchestra, e.g. pianists, violinists, percussionists, etc. When barriers are used, these groups listen to each other via headphones. Multitrack recording Multitrack recording (MTR)—also known as multitracking, double tracking, or tracking—is a method of sound recording developed in 1955 that allows for the separate
Multitrack recording
13037494
both light and electron microscopy. Use of alcian blue has historically been a popular staining method in histology especially for light microscopy in paraffin embedded sections and in semithin resin sections. The tissue parts that specifically stain by this dye become blue to bluish-green after staining and are called "Alcianophilic" (comparable to "eosinophilic" or "sudanophilic"). Alcian blue staining can be combined with H&E staining, PAS staining and van Gieson staining methods. Alcian blue can be used to quantitate acidic glycans both in microspectrophotometric quantitation in solution or for staining glycoproteins in polyacrylamide gels or on western blots. Biochemists had used
Alcian blue stain
13195204
has wide lips that contain papilla. All members of "Syndontis" have a structure called a premaxillary toothpad, which is located on the very front of the upper jaw of the mouth. This structure contains several rows of short, chisel-shaped teeth. In some species, this toothpad is made up of a large patch with several rows in a large cluster. In other species of "Syndontis", this toothpad is clearly divided into two separate groups, separated by a thin band of skin that divides the toothpad. This character is used as a method of differentiating between two different but similar species of
Synodontis ilebrevis
13195178
a premaxillary toothpad, which is located on the very front of the upper jaw of the mouth. This structure contains several rows of short, chisel-shaped teeth. In some species, this toothpad is made up of a large patch with several rows in a large cluster. In other species of "Syndontis", this toothpad is clearly divided into two separate groups, separated by a thin band of skin that divides the toothpad. This character is used as a method of differentiating between to different but similar species of "Syndontis". In "S. grandiops", the toothpad is uninterrupted, or continuous without a break. On
Synodontis grandiops
10698005
downward and has wide lips that contain papilla. All members of "Syndontis" have a structure called a premaxillary toothpad, which is located on the very front of the upper jaw of the mouth. This structure contains several rows of short, chisel-shaped teeth. In some species, this toothpad is made up of a large patch with several rows in a large cluster. In other species of "Syndontis", this toothpad is clearly divided into two separate groups, separated by a thin band of skin that divides the toothpad. This character is used as a method of differentiating between two different but similar
Synodontis polli
12886874
glucose level. Gram staining of the sample may demonstrate bacteria in bacterial meningitis, but absence of bacteria does not exclude bacterial meningitis as they are only seen in 60% of cases; this figure is reduced by a further 20% if antibiotics were administered before the sample was taken. Gram staining is also less reliable in particular infections such as listeriosis. Microbiological culture of the sample is more sensitive (it identifies the organism in 70–85% of cases) but results can take up to 48 hours to become available. The type of white blood cell predominantly present (see table) indicates whether meningitis
Meningitis
7661002
Stain A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon. They are caused by the chemical or physical interaction of two dissimilar materials. Staining is used for biochemical research, metal staining, and art (e.g., wood staining, stained glass). There can be intentional stains (such as wood stains or paint), indicative stains (such as food coloring or adding a substance to make bacteria visible under a microscope), natural stains (such as rust on iron or a patina on bronze), and accidental stains such as ketchup on a shirt. Different types
Stain
5224164
no moisture remains. The red dye is then displaced by a yellow dye in a solvent, such as cellosolve (2-ethoxy-ethanol). The name "yellowsolve" is a blend of the terms "yellow" and "cellosolve". Lendrum's phloxine-tartrazine for cell inclusions is one example of a yellowsolve stain. Among the dyes used for trichrome staining are: Trichrome staining Trichrome staining is a histological staining method that uses two or more acid dyes in conjunction with a polyacid. Staining differentiates tissues by tinting them in contrasting colours. It increases the contrast of microscopic features in cells and tissues, which makes them easier to see when
Trichrome staining
12220517
light shows all the wavelengths for which the particle has the higher refractive index. These effects are seen with the particle in sharp focus. This is a significant advantage over the Becke` line method because the particle doesn’t have to be defocus to see the colors and generally the colors are more distinct than are the Becke` line dispersion colors. The colors seen with this type of dispersion staining are about the same as those with the Becke` Line method shown in Chart 1. Examples of this type of dispersion staining and the colors shown for different λo’s can be
Dispersion staining
167601
with the Gram stain, yield a gram-variable pattern: a mix of pink and purple cells are seen. In cultures of Bacillus, Butyrivibrio, and Clostridium, a decrease in peptidoglycan thickness during growth coincides with an increase in the number of cells that stain gram-negative. In addition, in all bacteria stained using the Gram stain, the age of the culture may influence the results of the stain. Gram-indeterminate bacteria do not respond predictably to Gram staining and, therefore, cannot be determined as either gram-positive or gram-negative. Examples include many species of "Mycobacterium", including "M. tuberculosis" and "M. leprae". The term 'Gram staining'
Gram stain
9839515
and with Stanley Cobb, the development of intravital silver staining. The eponymous "Bielschowsky silver stain" technique was an improvement on the method developed by Ramon y Cajal (1852-1934). Max Bielschowsky Max Bielschowsky (February 19, 1869 – August 15, 1940) was a German neuropathologist born in Breslau. After receiving his medical doctorate from the University of Munich in 1893, he worked with Ludwig Edinger (1855-1918) at the Senckenberg Pathology Institute in Frankfurt-am-Main. At Senckenberg he learned histological staining techniques from Carl Weigert (1845-1904). From 1896 to 1904 he worked in Emanuel Mendel's (1839-1907) psychiatric laboratory in Berlin. In 1904 he joined
Max Bielschowsky
17005125
staining and quantity of nucleic acid present. Its method of binding and specificity are still not completely known. However, it is thought that gallocyanin-Cr(HO) selectively binds to nucleic acid phosphate groups, particularly within a pH range of 1.5-1.75. Gallocyanin stain The gallocyanin stain, also known as the gallocyanin-chromalum stain, is a stain of the oxazine group for total nucleic acids. It is prepared from gallocyanin and is an ideal method for numerous slides that need to be stained serially, equivalently, and reproducible. Structures containing basophilic compounds take on a bluish color. It has been known since the early work of
Gallocyanin stain
30031
amides. Long toxicology and outcome studies are needed with such compounds to disprove a positive Ames test. The Ames test was initially developed using agar plates (the plate incorporation technique), as described above. Since that time, a popular alternative to performing the Ames test has been developed, which is known as the "fluctuation method". This technique is the same in concept as the agar-based method, with bacteria being added to a reaction mixture with a small amount of histidine, which allows the bacteria to grow and mutate, returning to synthesize their own histidine. By including a pH indicator, the frequency
Ames test