Bacteria which retain the crystal violet stain when treated by Gram's method.

Heat and stain resistant, metabolically inactive bodies formed within the vegetative cells of bacteria of the genera Bacillus and Clostridium.

Bacteria which lose crystal violet stain but are stained pink when treated by Gram's method.

One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.

A broad range of biologically active compounds which occur naturally in plants having important medicinal and nutritional properties.

Substances that reduce the growth or reproduction of BACTERIA.

Infections caused by bacteria that retain the crystal violet stain (positive) when treated by the gram-staining method.

The sumac plant family in the order Sapindales, subclass Rosidae, class Magnoliopsida. They are tropical and subtropical trees, shrubs, and woody vines that have resin ducts in the bark. The sap of many of the species is irritating to the skin.

A species of gram-positive bacteria that is a common soil and water saprophyte.

Chronic, localized granulomatous infection of mucocutaneous tissues, especially the NOSE, and characterized by HYPERPLASIA and the development of POLYPS. It is found in humans and other animals and is caused by the mesomycetozoean organism RHINOSPORIDIUM SEEBERI.

Any tests that demonstrate the relative efficacy of different chemotherapeutic agents against specific microorganisms (i.e., bacteria, fungi, viruses).

Concentrated pharmaceutical preparations of plants obtained by removing active constituents with a suitable solvent, which is evaporated away, and adjusting the residue to a prescribed standard.

A kingdom of eukaryotic, heterotrophic organisms that live parasitically as saprobes, including MUSHROOMS; YEASTS; smuts, molds, etc. They reproduce either sexually or asexually, and have life cycles that range from simple to complex. Filamentous fungi, commonly known as molds, refer to those that grow as multicellular colonies.

Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method.

Substances that prevent infectious agents or organisms from spreading or kill infectious agents in order to prevent the spread of infection.

Constituent of 30S subunit prokaryotic ribosomes containing 1600 nucleotides and 21 proteins. 16S rRNA is involved in initiation of polypeptide synthesis.

A mitosporic fungal genus which causes COCCIDIOIDOMYCOSIS.

A genus of BACILLACEAE that are spore-forming, rod-shaped cells. Most species are saprophytic soil forms with only a few species being pathogenic.

'Anaerobic Bacteria' are types of bacteria that do not require oxygen for growth and can often cause diseases in humans, including dental caries, gas gangrene, and tetanus, among others.

Bacteria that form endospores and are gram-positive. Representative genera include BACILLUS; CLOSTRIDIUM; MICROMONOSPORA; SACCHAROPOLYSPORA; and STREPTOMYCES.

Picolinic acid is an organic compound that belongs to the class of pyridine derivatives, acting as a chelating agent in mammals, primarily found in the liver and kidneys, and playing a significant role in the metabolism of proteins, vitamins, and minerals.

Coccus-shaped bacteria that retain the crystal violet stain when treated by Gram's method.

Deoxyribonucleic acid that makes up the genetic material of bacteria.

A method where a culturing surface inoculated with microbe is exposed to small disks containing known amounts of a chemical agent resulting in a zone of inhibition (usually in millimeters) of growth of the microbe corresponding to the susceptibility of the strain to the agent.

Proteins found in any species of bacterium.

The reproductive elements of lower organisms, such as BACTERIA; FUNGI; and cryptogamic plants.

Infections by bacteria, general or unspecified.

The relationships of groups of organisms as reflected by their genetic makeup.

Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.

The presence of viable bacteria circulating in the blood. Fever, chills, tachycardia, and tachypnea are common acute manifestations of bacteremia. The majority of cases are seen in already hospitalized patients, most of whom have underlying diseases or procedures which render their bloodstreams susceptible to invasion.

A species of bacteria that causes ANTHRAX in humans and animals.

Potentially pathogenic bacteria found in nasal membranes, skin, hair follicles, and perineum of warm-blooded animals. They may cause a wide range of infections and intoxications.

A species of rod-shaped bacteria that is a common soil saprophyte. Its spores are widespread and multiplication has been observed chiefly in foods. Contamination may lead to food poisoning.

A species of gram-positive bacteria in the family Clostridiaceae, used for the industrial production of SOLVENTS.

Enumeration by direct count of viable, isolated bacterial, archaeal, or fungal CELLS or SPORES capable of growth on solid CULTURE MEDIA. The method is used routinely by environmental microbiologists for quantifying organisms in AIR; FOOD; and WATER; by clinicians for measuring patients' microbial load; and in antimicrobial drug testing.

A family of bacteria which produce endospores. They are mostly saprophytes from soil, but a few are insect or animal parasites or pathogens.

A species of gram-positive, coccoid bacteria commonly isolated from clinical specimens and the human intestinal tract. Most strains are nonhemolytic.

A group of rods or cocci whose taxonomic affinities are uncertain. They form endospores, thick-walled bodies formed within the vegetative cells of certain bacteria, able to withstand adverse environmental conditions for prolonged periods.

Infection with a fungus of the genus COCCIDIOIDES, endemic to the SOUTHWESTERN UNITED STATES. It is sometimes called valley fever but should not be confused with RIFT VALLEY FEVER. Infection is caused by inhalation of airborne, fungal particles known as arthroconidia, a form of FUNGAL SPORES. A primary form is an acute, benign, self-limited respiratory infection. A secondary form is a virulent, severe, chronic, progressive granulomatous disease with systemic involvement. It can be detected by use of COCCIDIOIDIN.

DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.

A dye that is a mixture of violet rosanilinis with antibacterial, antifungal, and anthelmintic properties.

A genus of anaerobic bacteria in the family Peptococcaceae, widely distributed in SOIL and the RUMEN of animals. Stains gram-negative but cell wall is gram-positive type.

A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.

The Arctic Ocean and the lands in it and adjacent to it. It includes Point Barrow, Alaska, most of the Franklin District in Canada, two thirds of Greenland, Svalbard, Franz Josef Land, Lapland, Novaya Zemlya, and Northern Siberia. (Webster's New Geographical Dictionary, 1988, p66)

A purine nucleoside that has hypoxanthine linked by the N9 nitrogen to the C1 carbon of ribose. It is an intermediate in the degradation of purines and purine nucleosides to uric acid and in pathways of purine salvage. It also occurs in the anticodon of certain transfer RNA molecules. (Dorland, 28th ed)

Photosensitive afferent neurons located in the peripheral retina, with their density increases radially away from the FOVEA CENTRALIS. Being much more sensitive to light than the RETINAL CONE CELLS, the rod cells are responsible for twilight vision (at scotopic intensities) as well as peripheral vision, but provide no color discrimination.

Infections with bacteria of the genus STAPHYLOCOCCUS.

The relative amounts of the PURINES and PYRIMIDINES in a nucleic acid.

Peptidoglycan is a complex, cross-linked polymer of carbohydrates and peptides that forms the rigid layer of the bacterial cell wall, providing structural support and protection while contributing to the bacterium's susceptibility or resistance to certain antibiotics.

Phenazines are nitrogen-containing heterocyclic compounds that have been widely studied for their antibacterial, antifungal, and antiparasitic properties, and can be found in various natural sources such as bacteria and fungi, or synthesized chemically.

Substances that destroy fungi by suppressing their ability to grow or reproduce. They differ from FUNGICIDES, INDUSTRIAL because they defend against fungi present in human or animal tissues.

3-Acetyl-5-sec-butyl-4-hydroxy-3-pyrrolin-2-one. A metabolite found in a strain of the fungus Alternaria tenuis Auct. which functions as an antibiotic with antiviral and antineoplastic properties, and may also act as a mycotoxin.

A vegetative stage in the life cycle of sporozoan protozoa. It is characteristic of members of the phyla APICOMPLEXA and MICROSPORIDIA.

A genus of motile or nonmotile gram-positive bacteria of the family Clostridiaceae. Many species have been identified with some being pathogenic. They occur in water, soil, and in the intestinal tract of humans and lower animals.

The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.

Compounds consisting of glucosamine and lactate joined by an ether linkage. They occur naturally as N-acetyl derivatives in peptidoglycan, the characteristic polysaccharide composing bacterial cell walls. (From Dorland, 28th ed)

A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.

The destroying of all forms of life, especially microorganisms, by heat, chemical, or other means.

A large group of rod-shaped bacteria that retains the crystal violet stain when treated by Gram's method.

Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).

A protein which is a subunit of RNA polymerase. It effects initiation of specific RNA chains from DNA.

Presence of warmth or heat or a temperature notably higher than an accustomed norm.

Diaminopimelic acid (DAP) is a crucial intermediate in the biosynthesis of L-lysine, an essential amino acid, and is also a significant component of peptidoglycan, a cell wall polymer in bacteria.

A moderate-growing, photochromogenic species found in aquariums, diseased fish, and swimming pools. It is the cause of cutaneous lesions and granulomas (swimming pool granuloma) in humans. (Dorland, 28th ed)

A family of gram-positive, saprophytic bacteria occurring in soil and aquatic environments.

Reproductive bodies produced by fungi.

An infant during the first month after birth.

The presence of bacteria, viruses, and fungi in the soil. This term is not restricted to pathogenic organisms.

Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.

Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.

Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.

Ability of a microbe to survive under given conditions. This can also be related to a colony's ability to replicate.

A copper-containing oxidoreductase enzyme that catalyzes the oxidation of 4-benzenediol to 4-benzosemiquinone. It also has activity towards a variety of O-quinols and P-quinols. It primarily found in FUNGI and is involved in LIGNIN degradation, pigment biosynthesis and detoxification of lignin-derived products.

A mass of organic or inorganic solid fragmented material, or the solid fragment itself, that comes from the weathering of rock and is carried by, suspended in, or dropped by air, water, or ice. It refers also to a mass that is accumulated by any other natural agent and that forms in layers on the earth's surface, such as sand, gravel, silt, mud, fill, or loess. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed, p1689)

Genes, found in both prokaryotes and eukaryotes, which are transcribed to produce the RNA which is incorporated into RIBOSOMES. Prokaryotic rRNA genes are usually found in OPERONS dispersed throughout the GENOME, whereas eukaryotic rRNA genes are clustered, multicistronic transcriptional units.

Rod-shaped bacteria that form endospores and are gram-positive. Representative genera include BACILLUS and CLOSTRIDIUM.

The use of instrumentation and techniques for visualizing material and details that cannot be seen by the unaided eye. It is usually done by enlarging images, transmitted by light or electron beams, with optical or magnetic lenses that magnify the entire image field. With scanning microscopy, images are generated by collecting output from the specimen in a point-by-point fashion, on a magnified scale, as it is scanned by a narrow beam of light or electrons, a laser, a conductive probe, or a topographical probe.

A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.

An acute infection caused by the spore-forming bacteria BACILLUS ANTHRACIS. It commonly affects hoofed animals such as sheep and goats. Infection in humans often involves the skin (cutaneous anthrax), the lungs (inhalation anthrax), or the gastrointestinal tract. Anthrax is not contagious and can be treated with antibiotics.

The marking of biological material with a dye or other reagent for the purpose of identifying and quantitating components of tissues, cells or their extracts.

A ubiquitous sodium salt that is commonly used to season food.

Ribonucleic acid in bacteria having regulatory and catalytic roles as well as involvement in protein synthesis.

Water containing no significant amounts of salts, such as water from RIVERS and LAKES.

Procedures for identifying types and strains of bacteria. The most frequently employed typing systems are BACTERIOPHAGE TYPING and SEROTYPING as well as bacteriocin typing and biotyping.

Rendering pathogens harmless through the use of heat, antiseptics, antibacterial agents, etc.

The presence of bacteria, viruses, and fungi in the air. This term is not restricted to pathogenic organisms.

Emission of LIGHT when ELECTRONS return to the electronic ground state from an excited state and lose the energy as PHOTONS. It is sometimes called cool light in contrast to INCANDESCENCE. LUMINESCENT MEASUREMENTS take advantage of this type of light emitted from LUMINESCENT AGENTS.

The presence of bacteria, viruses, and fungi in water. This term is not restricted to pathogenic organisms.

An azo dye used in blood volume and cardiac output measurement by the dye dilution method. It is very soluble, strongly bound to plasma albumin, and disappears very slowly.

Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)

Techniques used in studying bacteria.

In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.

The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.

The functional hereditary units of BACTERIA.

A broad class of substances containing carbon and its derivatives. Many of these chemicals will frequently contain hydrogen with or without oxygen, nitrogen, sulfur, phosphorus, and other elements. They exist in either carbon chain or carbon ring form.

Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.

The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.

Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.

Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.

A species of GRAM-POSITIVE ENDOSPORE-FORMING BACTERIA in the family BACILLACEAE, found in soil, hot springs, Arctic waters, ocean sediments, and spoiled food products.

A non-essential amino acid that occurs in high levels in its free state in plasma. It is produced from pyruvate by transamination. It is involved in sugar and acid metabolism, increases IMMUNITY, and provides energy for muscle tissue, BRAIN, and the CENTRAL NERVOUS SYSTEM.

An order of the Amphibia class which includes salamanders and newts. They are characterized by usually having slim bodies and tails, four limbs of about equal size (except in Sirenidae), and a reduction in skull bones.

The adjustment of the eye to variations in the intensity of light. Light adaptation is the adjustment of the eye when the light threshold is increased; DARK ADAPTATION when the light is greatly reduced. (From Cline et al., Dictionary of Visual Science, 4th ed)

A genus of the Ambystomatidae family. The best known species are the axolotl AMBYSTOMA MEXICANUM and the closely related tiger salamander Ambystoma tigrinum. They may retain gills and remain aquatic without developing all of the adult characteristics. However, under proper changes in the environment they metamorphose.

Analysis of the intensity of Raman scattering of monochromatic light as a function of frequency of the scattered light.

The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)

Photosensitive protein complexes of varied light absorption properties which are expressed in the PHOTORECEPTOR CELLS. They are OPSINS conjugated with VITAMIN A-based chromophores. Chromophores capture photons of light, leading to the activation of opsins and a biochemical cascade that ultimately excites the photoreceptor cells.

A group of gram-negative bacteria consisting of rod- and coccus-shaped cells. They are both aerobic (able to grow under an air atmosphere) and microaerophilic (grow better in low concentrations of oxygen) under nitrogen-fixing conditions but, when supplied with a source of fixed nitrogen, they grow as aerobes.

Photosensitive proteins expressed in the ROD PHOTORECEPTOR CELLS. They are the protein components of rod photoreceptor pigments such as RHODOPSIN.

That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.

Microscopy in which the object is examined directly by an electron beam scanning the specimen point-by-point. The image is constructed by detecting the products of specimen interactions that are projected above the plane of the sample, such as backscattered electrons. Although SCANNING TRANSMISSION ELECTRON MICROSCOPY also scans the specimen point by point with the electron beam, the image is constructed by detecting the electrons, or their interaction products that are transmitted through the sample plane, so that is a form of TRANSMISSION ELECTRON MICROSCOPY.

The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.

The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

Thiazoles are heterocyclic organic compounds containing a sulfur atom and a nitrogen atom, which are bound by two carbon atoms to form a five-membered ring, and are widely found in various natural and synthetic substances, including some pharmaceuticals and vitamins.

A species of the true toads, Bufonidae, becoming fairly common in the southern United States and almost pantropical. The secretions from the skin glands of this species are very toxic to animals.

A large group of facultatively anaerobic, rod-shaped bacteria that show up as pink (negative) when treated by the gram-staining method.

The portion of a retinal rod cell situated between the ROD INNER SEGMENT and the RETINAL PIGMENT EPITHELIUM. It contains a stack of photosensitive disk membranes laden with RHODOPSIN.

The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.

Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.

The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.

A purplish-red, light-sensitive pigment found in RETINAL ROD CELLS of most vertebrates. It is a complex consisting of a molecule of ROD OPSIN and a molecule of 11-cis retinal (RETINALDEHYDE). Rhodopsin exhibits peak absorption wavelength at about 500 nm.

The genetic complement of a BACTERIA as represented in its DNA.

The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.

Analytical technique for studying substances present at enzyme concentrations in single cells, in situ, by measuring light absorption. Light from a tungsten strip lamp or xenon arc dispersed by a grating monochromator illuminates the optical system of a microscope. The absorbance of light is measured (in nanometers) by comparing the difference between the image of the sample and a reference image.

Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.

A genus of gram-negative, anaerobic, rod-shaped bacteria. Its organisms are found in the human vagina, particularly in association with Gardnerella vaginalis in cases of bacterial vaginosis.

Specialized PHOTOTRANSDUCTION neurons in the vertebrates, such as the RETINAL ROD CELLS and the RETINAL CONE CELLS. Non-visual photoreceptor neurons have been reported in the deep brain, the PINEAL GLAND and organs of the circadian system.

Polymicrobial, nonspecific vaginitis associated with positive cultures of Gardnerella vaginalis and other anaerobic organisms and a decrease in lactobacilli. It remains unclear whether the initial pathogenic event is caused by the growth of anaerobes or a primary decrease in lactobacilli.

The conversion of absorbed light energy into molecular signals.

Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.

A heterotrimeric GTP-binding protein that mediates the light activation signal from photolyzed rhodopsin to cyclic GMP phosphodiesterase and is pivotal in the visual excitation process. Activation of rhodopsin on the outer membrane of rod and cone cells causes GTP to bind to transducin followed by dissociation of the alpha subunit-GTP complex from the beta/gamma subunits of transducin. The alpha subunit-GTP complex activates the cyclic GMP phosphodiesterase which catalyzes the hydrolysis of cyclic GMP to 5'-GMP. This leads to closure of the sodium and calcium channels and therefore hyperpolarization of the rod cells. EC 3.6.1.-.

The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.

A species in the genus GARDNERELLA previously classified as Haemophilus vaginalis. This bacterium, also isolated from the female genital tract of healthy women, is implicated in the cause of bacterial vaginosis (VAGINOSIS, BACTERIAL).

Recording of electric potentials in the retina after stimulation by light.

A retrogressive pathological change in the retina, focal or generalized, caused by genetic defects, inflammation, trauma, vascular disease, or aging. Degeneration affecting predominantly the macula lutea of the retina is MACULAR DEGENERATION. (Newell, Ophthalmology: Principles and Concepts, 7th ed, p304)

Photosensitive proteins in the membranes of PHOTORECEPTOR CELLS such as the rods and the cones. Opsins have varied light absorption properties and are members of the G-PROTEIN-COUPLED RECEPTORS family. Their ligands are VITAMIN A-based chromophores.

A large group of anaerobic bacteria which show up as pink (negative) when treated by the Gram-staining method.

A species of the true toads, Bufonidae, widely distributed in the United States and Europe.

'Eye proteins' are structural or functional proteins, such as crystallins, opsins, and collagens, located in various parts of the eye, including the cornea, lens, retina, and aqueous humor, that contribute to maintaining transparency, refractive power, phototransduction, and overall integrity of the visual system.

Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.

A PROTEIN-SERINE-THREONINE KINASE that is found in PHOTORECEPTOR CELLS. It mediates light-dependent PHOSPHORYLATION of RHODOPSIN and plays an important role in PHOTOTRANSDUCTION.

A large group of aerobic bacteria which show up as pink (negative) when treated by the gram-staining method. This is because the cell walls of gram-negative bacteria are low in peptidoglycan and thus have low affinity for violet stain and high affinity for the pink dye safranine.

The absence of light.

Elements of limited time intervals, contributing to particular results or situations.

Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.

Determination of parasite eggs in feces.

A gram-positive, non-spore-forming group of bacteria comprising organisms that have morphological and physiological characteristics in common.

Excrement from the INTESTINES, containing unabsorbed solids, waste products, secretions, and BACTERIA of the DIGESTIVE SYSTEM.

The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.

The salinated water of OCEANS AND SEAS that provides habitat for marine organisms.

A 48-Kd protein of the outer segment of the retinal rods and a component of the phototransduction cascade. Arrestin quenches G-protein activation by binding to phosphorylated photolyzed rhodopsin. Arrestin causes experimental autoimmune uveitis when injected into laboratory animals.

A carotenoid constituent of visual pigments. It is the oxidized form of retinol which functions as the active component of the visual cycle. It is bound to the protein opsin forming the complex rhodopsin. When stimulated by visible light, the retinal component of the rhodopsin complex undergoes isomerization at the 11-position of the double bond to the cis-form; this is reversed in "dark" reactions to return to the native trans-configuration.

The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)

INTERNEURONS of the vertebrate RETINA containing two processes. They receive inputs from the RETINAL PHOTORECEPTOR CELLS and send outputs to the RETINAL GANGLION CELLS. The bipolar cells also make lateral connections in the retina with the RETINAL HORIZONTAL CELLS and with the AMACRINE CELLS.

Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)

A genus of gram-positive, microaerophilic, rod-shaped bacteria occurring widely in nature. Its species are also part of the many normal flora of the mouth, intestinal tract, and vagina of many mammals, including humans. Pathogenicity from this genus is rare.

Life or metabolic reactions occurring in an environment containing oxygen.

Neuronal calcium sensor proteins that regulate the activation of membrane-bound GUANYLATE CYCLASE. They are primarily expressed in the RETINA where they play an important role in PHOTOTRANSDUCTION.