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Oxidase Test
The oxidase test is used to determine if an organism possesses the cytochrome c oxidase enzyme. The test is used as an aid for the differentiation of ''Neisseria'', ''Moraxella'', '' Campylobacter'' and ''Pasteurella'' species (oxidase positive). It is also used to differentiate pseudomonads from related species.MacFaddin JF, editor. Biochemical Tests for Identification of Medical Bacteria. 3rd ed. Philadelphia:Lippincott Williams and Wilkins; 2000. p. 363-7 Classification Strains may be either oxidase-positive (OX+) or oxidase-negative (OX-). OX+ OX+ normally means the bacterium contains cytochrome c oxidase (also known as Complex IV) and can therefore use oxygen for energy production by converting O2 to H2O2 or H2O with an electron transfer chain. The Pseudomonadaceae are typically OX+. The Gram-negative diplococci Neisseria and Moraxella are oxidase-positive. Many Gram-negative, spiral curved rods are also oxidase-positive, which includes ''Helicobacter pylori'', ''Vibrio cho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytochrome C Oxidase
The enzyme cytochrome c oxidase or Complex IV, (was , now reclassified as a translocasEC 7.1.1.9 is a large transmembrane protein complex found in bacteria, archaea, and mitochondria of eukaryotes. It is the last enzyme in the respiratory electron transport chain of cells located in the membrane. It receives an electron from each of four cytochrome c molecules and transfers them to one oxygen molecule and four protons, producing two molecules of water. In addition to binding the four protons from the inner aqueous phase, it transports another four protons across the membrane, increasing the transmembrane difference of proton electrochemical potential, which the ATP synthase then uses to synthesize ATP. Structure The complex The complex is a large integral membrane protein composed of several metal prosthetic sites and 14 protein subunits in mammals. In mammals, eleven subunits are nuclear in origin, and three are synthesized in the mitochondria. The complex contains two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sterile Technique
Asepsis is the state of being free from disease-causing micro-organisms (such as pathogenic bacteria, viruses, pathogenic fungi, and parasites). There are two categories of asepsis: medical and surgical. The modern day notion of asepsis is derived from the older antiseptic techniques, a shift initiated by different individuals in the 19th century who introduced practices such as the sterilizing of surgical tools and the wearing of surgical gloves during operations. The goal of asepsis is to eliminate infection, not to achieve sterility. Ideally, a surgical field is sterile, meaning it is free of all biological contaminants (e.g. fungi, bacteria, viruses), not just those that can cause disease, putrefaction, or fermentation. Even in an aseptic state, a condition of sterile inflammation may develop. The term often refers to those practices used to promote or induce asepsis in an operative field of surgery or medicine to prevent infection. History The modern concept of asepsis e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trypticase Soy Agar
Trypticase soy agar or tryptone soya agar (TSA) and Trypticase soy broth or tryptone soya broth (TSB) with agar are growth media for the culturing of bacteria. They are general-purpose, nonselective media providing enough nutrients to allow for a wide variety of microorganisms to grow. They are used for a wide range of applications, including culture storage, enumeration of cells (counting), isolation of pure cultures, or simply general culture. TSA contains enzymatic digests of casein and soybean meal, which provide amino acids and other nitrogenous substances, making it a nutritious medium for a variety of organisms. Glucose is the energy source. Sodium chloride maintains the osmotic equilibrium, while dipotassium phosphate acts as buffer to maintain pH. Agar extracted from any number of organisms is used as a gelling agent. The medium may be supplemented with blood to facilitate the growth of more fastidious bacteria or antimicrobial agents to permit the selection of vario ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catalase Test
Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals) which catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting the cell from oxidative damage by reactive oxygen species (ROS). Catalase has one of the highest turnover numbers of all enzymes; one catalase molecule can convert millions of hydrogen peroxide molecules to water and oxygen each second. Catalase is a tetramer of four polypeptide chains, each over 500 amino acids long. It contains four iron-containing heme groups that allow the enzyme to react with hydrogen peroxide. The optimum pH for human catalase is approximately 7, and has a fairly broad maximum: the rate of reaction does not change appreciably between pH 6.8 and 7.5. The pH optimum for other catalases varies between 4 and 11 depending on the species. The optimum temperature also varies by species. Structure Human catalase forms a t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indophenol Blue
Indophenol is an organic compound with the formula OC6H4NC6H4OH. It is deep blue dye that is the product of the Berthelot's reaction, a common test for ammonia. The indophenol group, with various substituents in place of O''H'' and various ring substitutions, is found in many dyes used in hair coloring and textiles. Indophenol is used in hair dyes, lubricants, redox materials, liquid crystal displays, fuel cells and chemical-mechanical polishing. It is an environmental pollutant and is toxic to fish. Berthelot test In the Berthelot test (1859), a sample suspected of having containing ammonia is treated with sodium hypochlorite and phenol. The formation of indophenol is used to determine ammonia and paracetamol by spectrophotometry. Other phenols can be used. Dichlorophenol-indophenol (DCPIP), a form of indophenol, is often used to determine the presence of vitamin C ( ascorbic acid). Related compounds Indophenol blue is a different compound with systematic name A systema ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NADH
Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine nucleobase and the other nicotinamide. NAD exists in two forms: an oxidized and reduced form, abbreviated as NAD and NADH (H for hydrogen), respectively. In metabolism, nicotinamide adenine dinucleotide is involved in redox reactions, carrying electrons from one reaction to another. The cofactor is, therefore, found in two forms in cells: NAD is an oxidizing agent – it accepts electrons from other molecules and becomes reduced. This reaction, also with H+, forms NADH, which can then be used as a reducing agent to donate electrons. These electron transfer reactions are the main function of NAD. However, it is also used in other cellular processes, most notably as a substrate of enzymes in adding or removing chemical groups t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Indophenol Oxidase
Indophenol is an organic compound with the formula OC6H4NC6H4OH. It is deep blue dye that is the product of the Berthelot's reaction, a common test for ammonia. The indophenol group, with various substituents in place of O''H'' and various ring substitutions, is found in many dyes used in hair coloring and textiles. Indophenol is used in hair dyes, lubricants, redox materials, liquid crystal displays, fuel cells and chemical-mechanical polishing. It is an environmental pollutant and is toxic to fish. Berthelot test In the Berthelot test (1859), a sample suspected of having containing ammonia is treated with sodium hypochlorite and phenol. The formation of indophenol is used to determine ammonia and paracetamol by spectrophotometry. Other phenols can be used. Dichlorophenol-indophenol (DCPIP), a form of indophenol, is often used to determine the presence of vitamin C ( ascorbic acid). Related compounds Indophenol blue is a different compound with systematic name A systema ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maroon (color)
Maroon ( US/ UK , Australia ) is a brownish crimson color that takes its name from the French word ''marron'', or chestnut. "Marron" is also one of the French translations for "brown". According to multiple dictionaries, there are variabilities in defining the color maroon. The ''Cambridge English Dictionary'' defines maroon as a dark reddish-purple color while its "American Dictionary" section defines maroon as dark brown-red. This suggests slight perceptual differences in the U.K. versus North America. Lexico online dictionary defines maroon as a brownish-red. Similarly, Dictionary.com defines maroon as a dark brownish-red. The ''Oxford English Dictionary'' describes maroon as "a brownish crimson (strong red) or claret (purple color) color," while the Merriam-Webster online dictionary simply defines it as a dark red. In the sRGB color model for additive color representation, the web color called maroon is created by turning down the brightness of pure red to about o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redox
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. There are two classes of redox reactions: * ''Electron-transfer'' – Only one (usually) electron flows from the reducing agent to the oxidant. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * ''Atom transfer'' – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidation reactions are commonly associated with the formation of oxides, other chemical species can serve the same function. In hydrogen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DMPD
Dimethyl-4-phenylenediamine is an amine. It has been used as an accelerator for the vulcanization of rubber. It can be used in oxidase tests. Synthesis Dimethyl-4-phenylenediamine is made by the nitrosylation of dimethylaniline followed by reduction. Applications Dimethyl-4-phenylenediamine can be converted to methylene blue by reaction with dimethylaniline and sodium thiosulfate in several steps: : It is used as accelerator for the vulcanization of rubber, being first converted to the corresponding mercaptobenzothiazole 2-Mercaptobenzothiazole is an organosulfur compound with the formula . It is used in the sulfur vulcanization of rubber. Structure The molecule is planar with a C=S double bond, so the name ''mercapto''benzothiazole is a misnomer. It is not a th .... : References {{reflist Anilines Diamines Dimethylamino compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wurster's Blue
Wurster's blue is the trivial name given to the chemical ''N'',''N'',''N''′,''N''′-tetramethyl-''p''-phenylenediamine, also known as TMPD. It is an easily oxidised phenylenediamine, which loses two electrons in one-electron oxidation steps; the radical cation is a characteristic blue-violet colour, which gives the compound part of its name. The remaining part of its name comes from its discoverer, the German chemist Casimir Wurster (7 August 1854 – 29 November 1913). The hydrochloride salt finds use as a redox indicator in the oxidase test and is also used in electron transport chain analysis as it is capable of donating electrons to cytochrome c. The term "Wurster's blue" is often reserved for the radical cation, the colorless diamine being called tetramethylphenylenediamine (TMPD). The midpoint potential for titration of the first electron is given as 0.276 V vs NHE, and this transition is useful in potentiometric titrations as both a redox mediator and indicator. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
