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Chitobiose
Chitobioses are a group of related disaccharides of β-1,4-linked glucosamine units. The term ''chitobiose'' is sometimes used to refer to different members of the group, depending on the method by which it was first isolated, resulting in some ambiguity as to which chemical compound the name is referring to. Chitobiose is the condensed form of 4‐''O''‐(2‐amino‐2‐deoxy‐β‐D‐glucopyranosyl)‐2‐amino‐2‐deoxy‐D‐glucose and is an acetylation disaccharide found in chitin. It is formed by the depolymerization of chitin either enzymatically or chemically. Chitobiose is utilized by ''Borrelia burgdorferi'' to produce ''N''-acetylglucosamine, a component of the bacterial cell wall, and is regularized by the response regulator rrp1. A mutant strain of rrp1 has been found to cause growth deficits with ''Borrelia burgdorferi''. In ''Escherichia coli'', the chb operon is involved with the utilization of cellobiose and β-glucosides chitobiose. The chbG gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chitobiose Glucosamine
Chitobioses are a group of related disaccharides of β-1,4-linked glucosamine units. The term ''chitobiose'' is sometimes used to refer to different members of the group, depending on the method by which it was first isolated, resulting in some ambiguity as to which chemical compound the name is referring to. Chitobiose is the condensed form of 4‐''O''‐(2‐amino‐2‐deoxy‐β‐D‐glucopyranosyl)‐2‐amino‐2‐deoxy‐D‐glucose and is an acetylation disaccharide found in chitin. It is formed by the depolymerization of chitin either enzymatically or chemically. Chitobiose is utilized by ''Borrelia burgdorferi'' to produce ''N''-acetylglucosamine, a component of the bacterial cell wall, and is regularized by the response regulator rrp1. A mutant strain of rrp1 has been found to cause growth deficits with ''Borrelia burgdorferi''. In ''Escherichia coli'', the chb operon is involved with the utilization of cellobiose and β-glucosides chitobiose. The chbG gene of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chitobiose N,N-diacetylglucosamine
Chitobioses are a group of related disaccharides of β-1,4-linked glucosamine units. The term ''chitobiose'' is sometimes used to refer to different members of the group, depending on the method by which it was first isolated, resulting in some ambiguity as to which chemical compound the name is referring to. Chitobiose is the condensed form of 4‐''O''‐(2‐amino‐2‐deoxy‐β‐D‐glucopyranosyl)‐2‐amino‐2‐deoxy‐D‐glucose and is an acetylation disaccharide found in chitin. It is formed by the depolymerization of chitin either enzymatically or chemically. Chitobiose is utilized by ''Borrelia burgdorferi'' to produce ''N''-acetylglucosamine, a component of the bacterial cell wall, and is regularized by the response regulator rrp1. A mutant strain of rrp1 has been found to cause growth deficits with ''Borrelia burgdorferi''. In ''Escherichia coli'', the chb operon is involved with the utilization of cellobiose and β-glucosides chitobiose. The chbG gene of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disaccharide
A disaccharide (also called a double sugar or ''biose'') is the sugar formed when two monosaccharides are joined by glycosidic linkage. Like monosaccharides, disaccharides are simple sugars soluble in water. Three common examples are sucrose, lactose, and maltose. Disaccharides are one of the four chemical groupings of carbohydrates (monosaccharides, disaccharides, oligosaccharides, and polysaccharides). The most common types of disaccharides—sucrose, lactose, and maltose—have 12 carbon atoms, with the general formula C12H22O11. The differences in these disaccharides are due to atomic arrangements within the molecule. The joining of monosaccharides into a double sugar happens by a condensation reaction, which involves the elimination of a water molecule from the functional groups only. Breaking apart a double sugar into its two monosaccharides is accomplished by hydrolysis with the help of a type of enzyme called a disaccharidase. As building the larger sugar ejects a water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucosamine
Glucosamine (C6H13NO5) is an amino sugar and a prominent precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of two polysaccharides, chitosan and chitin. Glucosamine is one of the most abundant monosaccharides. Produced commercially by the hydrolysis of shellfish exoskeletons or, less commonly, by fermentation of a grain such as corn or wheat, glucosamine has many names depending on country. Although a common dietary supplement, there is little evidence that it is effective for relief of arthritis or pain, and is not an approved prescription drug. Dietary supplement Oral glucosamine is a dietary supplement and is not a prescription drug. Glucosamine is marketed as a supplement to support the structure and function of joints, and the marketing is targeted to people with osteoarthritis. Commonly sold forms of glucosamine are glucosamine sulfate, glucosamine chondroitin, glucosamine hydrochloride, and ''N''-acetylglucos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chitin
Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chitin are produced each year in the biosphere. It is a primary component of cell walls in fungi (especially basidiomycetes and filamentous fungi), the exoskeletons of arthropods such as crustaceans and insects, the radulae, cephalopod beaks and gladii of molluscs and in some nematodes and diatoms. It is also synthesised by at least some fish and lissamphibians. Commercially, chitin is extracted from the shells of crabs, shrimps, shellfishes and lobsters, which are major by-products of the seafood industry. The structure of chitin is comparable to cellulose, forming crystalline nanofibrils or whiskers. It is functionally comparable to the protein keratin. Chitin has proved useful for several medicinal, industrial and biotechnological purpos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucosamine
Glucosamine (C6H13NO5) is an amino sugar and a prominent precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of two polysaccharides, chitosan and chitin. Glucosamine is one of the most abundant monosaccharides. Produced commercially by the hydrolysis of shellfish exoskeletons or, less commonly, by fermentation of a grain such as corn or wheat, glucosamine has many names depending on country. Although a common dietary supplement, there is little evidence that it is effective for relief of arthritis or pain, and is not an approved prescription drug. Dietary supplement Oral glucosamine is a dietary supplement and is not a prescription drug. Glucosamine is marketed as a supplement to support the structure and function of joints, and the marketing is targeted to people with osteoarthritis. Commonly sold forms of glucosamine are glucosamine sulfate, glucosamine chondroitin, glucosamine hydrochloride, and ''N''-acetylglucos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ambiguity
Ambiguity is the type of meaning in which a phrase, statement or resolution is not explicitly defined, making several interpretations plausible. A common aspect of ambiguity is uncertainty. It is thus an attribute of any idea or statement whose intended meaning cannot be definitively resolved according to a rule or process with a finite number of steps. (The '' ambi-'' part of the term reflects an idea of "two", as in "two meanings".) The concept of ambiguity is generally contrasted with vagueness. In ambiguity, specific and distinct interpretations are permitted (although some may not be immediately obvious), whereas with information that is vague, it is difficult to form any interpretation at the desired level of specificity. Linguistic forms Lexical ambiguity is contrasted with semantic ambiguity. The former represents a choice between a finite number of known and meaningful context-dependent interpretations. The latter represents a choice between any number of possi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylation
: In organic chemistry, acetylation is an organic esterification reaction with acetic acid. It introduces an acetyl group into a chemical compound. Such compounds are termed ''acetate esters'' or simply '' acetates''. Deacetylation is the opposite reaction, the removal of an acetyl group from a chemical compound. Organic synthesis Acetate esters and acetamides are generally prepared by acetylations. Acetylations are often used in making C-acetyl bonds in Friedel-Crafts reactions. Carbanions and their equivalents are susceptible to acetylations. Acetylation reagents Many acetylations are achieved using these three reagents: * Acetic anhydride. This reagent is common in the laboratory; its use cogenerates acetic acid. *Acetyl chloride. This reagent is also common in the laboratory, but its use cogenerates hydrogen chloride, which can be undesirable. *Ketene. At one time acetic anhydride was prepared by the reaction of ketene with acetic acid: :H2C=C=O + CH3COOH -> (CH3CO)2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borrelia Burgdorferi
''Borrelia burgdorferi'' is a bacterial species of the spirochete class in the genus ''Borrelia'', and is one of the causative agents of Lyme disease in humans. Along with a few similar genospecies, some of which also cause Lyme disease, it makes up the species complex of ''Borrelia burgdorferi'' sensu lato. The complex currently comprises 20 accepted and 3 proposed genospecies. ''B. burgdorferi'' sensu stricto exists in North America and Eurasia and until 2016 was the only known cause of Lyme disease in North America. ''Borrelia'' species are Gram-negative. Microbiology ''Borrelia burgdorferi'' is named after the researcher Willy Burgdorfer, who first isolated the bacterium in 1982. ''Borrelia burgdorferi'' is a microaerophile, requiring small amounts of oxygen in order to undergo glycolysis and survive. Like all other ''Borrelia'' sps., this bacterium is also gram-negative and a spirochete. Borrelia colonies are often smaller, rounded, and white with an elevated center. ''B. b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-Acetylglucosamine
''N''-Acetylglucosamine (GlcNAc) is an amide derivative of the monosaccharide glucose. It is a secondary amide between glucosamine and acetic acid. It is significant in several biological systems. It is part of a biopolymer in the bacterial cell wall, which is built from alternating units of GlcNAc and ''N''-acetylmuramic acid (MurNAc), cross-linked with oligopeptides at the lactic acid residue of MurNAc. This layered structure is called peptidoglycan (formerly called murein). GlcNAc is the monomeric unit of the polymer chitin, which forms the exoskeletons of arthropods like insects and crustaceans. It is the main component of the radulas of mollusks, the beaks of cephalopods, and a major component of the cell walls of most fungi. Polymerized with glucuronic acid, it forms hyaluronan. GlcNAc has been reported to be an inhibitor of elastase release from human polymorphonuclear leukocytes (range 8–17% inhibition), however this is much weaker than the inhibition seen wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escherichia Coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escherichia'' that is commonly found in the lower intestine of warm-blooded organisms. Most ''E. coli'' strains are harmless, but some serotypes ( EPEC, ETEC etc.) can cause serious food poisoning in their hosts, and are occasionally responsible for food contamination incidents that prompt product recalls. Most strains do not cause disease in humans and are part of the normal microbiota of the gut; such strains are harmless or even beneficial to humans (although these strains tend to be less studied than the pathogenic ones). For example, some strains of ''E. coli'' benefit their hosts by producing vitamin K2 or by preventing the colonization of the intestine by pathogenic bacteria. These mutually beneficial relationships between ''E. col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cellobiose
Cellobiose is a disaccharide with the formula (C6H7(OH)4O)2O. It is classified as a reducing sugar. In terms of its chemical structure, it is derived from the condensation of a pair of β-glucose molecules forming a β(1→4) bond. It can be hydrolyzed to glucose enzymatically or with acid. Cellobiose has eight free alcohol (OH) groups, one acetal linkage and one hemiacetal linkage, which give rise to strong inter- and intramolecular hydrogen bonds. It is a white solid. It can be obtained by enzymatic or acidic hydrolysis of cellulose and cellulose-rich materials such as cotton, jute, or paper. Cellobiose can be used as an indicator carbohydrate for Crohn's disease and malabsorption syndrome. Treatment of cellulose with acetic anhydride and sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
