|
Glucans
A glucan is a polysaccharide derived from D-glucose, linked by glycosidic bonds. Glucans are noted in two forms: alpha glucans and beta glucans. Many beta-glucans are medically important. They represent a drug target for antifungal medications of the echinocandin class. Types The following are glucans (The α- and β- and numbers clarify the type of O-glycosidic bond and the specific carbons involved): Alpha * dextran, α-1,6-glucan with α-1,3-branches * floridean starch, α-1,4- and α-1,6-glucan * glycogen, α-1,4- and α-1,6-glucan * pullulan, α-1,4- and α-1,6-glucan * starch, a mixture of amylose and amylopectin, both α-1,4- and α-1,6-glucans Beta * cellulose, β-1,4-glucan * chrysolaminarin, β-1,3-glucan * curdlan, β-1,3-glucan * laminarin, β-1,3- and β-1,6-glucan * lentinan, a strictly purified β-1,6:β-1,3-glucan from ''Lentinus edodes'' * lichenin, β-1,3- and β-1,4-glucan * oat beta-glucan, β-1,3- and β-1,4-glucan * pleuran, β-1,3- and β-1, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta-glucan
Beta-glucans, β-glucans comprise a group of β-D-glucose polysaccharides ( glucans) naturally occurring in the cell walls of cereals, bacteria, and fungi, with significantly differing physicochemical properties dependent on source. Typically, β-glucans form a linear backbone with 1–3 β-glycosidic bonds but vary with respect to molecular mass, solubility, viscosity, branching structure, and gelation properties, causing diverse physiological effects in animals. At dietary intake levels of at least 3 g per day, oat fiber β-glucan decreases blood levels of LDL cholesterol and so may reduce the risk of cardiovascular diseases. β-glucans are natural gums and are used as texturing agents in various nutraceutical and cosmetic products, and as soluble fiber supplements. History Cereal and fungal products have been used for centuries for medicinal and cosmetic purposes; however, the specific role of β-glucan was not explored until the 20th century. β-glucans were first discov ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polysaccharide
Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with water (hydrolysis) using amylase enzymes as catalyst, which produces constituent sugars (monosaccharides, or oligosaccharides). They range in structure from linear to highly branched. Examples include storage polysaccharides such as starch, glycogen and galactogen and structural polysaccharides such as cellulose and chitin. Polysaccharides are often quite heterogeneous, containing slight modifications of the repeating unit. Depending on the structure, these macromolecules can have distinct properties from their monosaccharide building blocks. They may be amorphous or even insoluble in water. When all the monosaccharides in a polysaccharide are the same type, the polysaccharide is called a homopolysaccharide or homoglycan, but when more t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lentinus Edodes
The shiitake (alternate form shitake) (; ''Lentinula edodes'') is an edible mushroom native to East Asia, which is now cultivated and consumed around the globe. It is considered a medicinal mushroom in some forms of traditional medicine. Taxonomy and naming The fungus was first described scientifically as ''Agaricus edodes'' by Miles Joseph Berkeley in 1877. It was placed in the genus ''Lentinula'' by David Pegler in 1976. The fungus has acquired an extensive synonymy in its taxonomic history: *''Agaricus edodes'' Berk. (1878) *''Armillaria edodes'' (Berk.) Sacc. (1887) *''Mastoleucomychelloes edodes'' (Berk.) Kuntze (1891) *''Cortinellus edodes'' (Berk.) S.Ito & S.Imai (1938) *''Lentinus edodes'' (Berk.) Singer (1941) *''Collybia shiitake'' J.Schröt. (1886) *''Lepiota shiitake'' (J.Schröt.) Nobuj. Tanaka (1889) *''Cortinellus shiitake'' (J.Schröt.) Henn. (1899) *''Tricholoma shiitake'' (J.Schröt.) Lloyd (1918) *''Lentinus shiitake'' (J.Schröt.) Singer (1936) *''Lentinus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monomer
In chemistry, a monomer ( ; ''mono-'', "one" + '' -mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization. Classification Monomers can be classified in many ways. They can be subdivided into two broad classes, depending on the kind of the polymer that they form. Monomers that participate in condensation polymerization have a different stoichiometry than monomers that participate in addition polymerization: : Other classifications include: *natural vs synthetic monomers, e.g. glycine vs caprolactam, respectively *polar vs nonpolar monomers, e.g. vinyl acetate vs ethylene, respectively *cyclic vs linear, e.g. ethylene oxide vs ethylene glycol, respectively The polymerization of one kind of monomer gives a homopolymer. Many polymers are copolymers, meaning that they are derived from two different monomers. In the case of condensation polymerizations, the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecular Weight
A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and ''molecule'' is often used when referring to polyatomic ions. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term ''molecule'' is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are typically not consi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoxy
Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also collectively called ''epoxy''. The IUPAC name for an epoxide group is an oxirane. Epoxy resins may be reacted (cross-linked) either with themselves through catalytic homopolymerisation, or with a wide range of co-reactants including polyfunctional amines, acids (and acid anhydrides), phenols, alcohols and thiols (usually called mercaptans). These co-reactants are often referred to as hardeners or curatives, and the cross-linking reaction is commonly referred to as curing. Reaction of polyepoxides with themselves or with polyfunctional hardeners forms a thermosetting polymer, often with favorable mechanical properties and high thermal and chemical resistance. Epoxy has a wide range of applications, including metal coatings, composites, use in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Levoglucosan
Levoglucosan (C6H10O5) is an organic compound with a six-carbon ring structure formed from the pyrolysis of carbohydrates, such as starch and cellulose. As a result, levoglucosan is often used as a chemical tracer for biomass burning in atmospheric chemistry studies, particularly with respect to airborne particulate matter. Along with other tracers such as potassium, oxalate, and gaseous acetonitrile, levoglucosan has been shown to be highly correlated with regional fires. This is because the gas emitted by the pyrolysis of wood (biomass) contains significant amounts of levoglucosan. Levoglucosan has been described as "an unequivocal biomass burning tracer" in the context of forest and brush fires. But the anhydrosugar has only been found detectable in low temperature samples (150-350 °C), meaning that its value as an indicator for smoke from controlled biomass combustion in, for instance, modern domestic wood stoves which operate at temperatures above 500 °C, is "ver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Structure Of Levoglucosan
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., without breaking chemical bonds. Chemical substances can be simple substances (substances consisting of a single chemical element), chemical compounds, or alloys. Chemical substances are often called 'pure' to set them apart from mixtures. A common example of a chemical substance is pure water; it has the same properties and the same ratio of hydrogen to oxygen whether it is isolated from a river or made in a laboratory. Other chemical substances commonly encountered in pure form are diamond (carbon), gold, table salt (sodium chloride) and refined sugar (sucrose). However, in practice, no substance is entirely pure, and chemical purity is specified according to the intended use of the chemical. Chemical substances exist as solids, liquids, g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GLUCOSE LG
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight, where it is used to make cellulose in cell walls, the most abundant carbohydrate in the world. In energy metabolism, glucose is the most important source of energy in all organisms. Glucose for metabolism is stored as a polymer, in plants mainly as starch and amylopectin, and in animals as glycogen. Glucose circulates in the blood of animals as blood sugar. The naturally occurring form of glucose is -glucose, while -glucose is produced synthetically in comparatively small amounts and is less biologically active. Glucose is a monosaccharide containing six carbon atoms and an aldehyde group, and is therefore an aldohexose. The glucose molecule can exist in an open-chain (acyclic) as well as ring (cyclic) form. Glucos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycosidic Bonds
A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate. A glycosidic bond is formed between the hemiacetal or hemiketal group of a saccharide (or a molecule derived from a saccharide) and the hydroxyl group of some compound such as an alcohol. A substance containing a glycosidic bond is a glycoside. The term 'glycoside' is now extended to also cover compounds with bonds formed between hemiacetal (or hemiketal) groups of sugars and several chemical groups other than hydroxyls, such as -SR (thioglycosides), -SeR (selenoglycosides), -NR1R2 (N-glycosides), or even -CR1R2R3 (C-glycosides). Particularly in naturally occurring glycosides, the compound ROH from which the carbohydrate residue has been removed is often termed the aglycone, and the carbohydrate residue itself is sometimes referred to as the 'glycone'. S-, N-, C-, and O-glycosidic bonds Glycosid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zymosan
Zymosan is a glucan with repeating glucose units connected by β-1,3-glycosidic linkages. It binds to TLR 2 and Dectin-1 (CLEC7A C-type lectin domain family 7 member A or Dectin-1 is a protein that in humans is encoded by the ''CLEC7A'' gene. CLEC7A is a member of the C-type lectin/C-type lectin-like domain (CTL/CTLD) superfamily. The encoded glycoprotein is a small type II ...). Zymosan is a ligand found on the surface of fungi, like yeast. Zymosan is prepared from yeast cell wall and consists of protein-carbohydrate complexes. It is used to induce experimental sterile inflammation. In macrophages, zymosan-induced responses include the induction of proinflammatory cytokines, arachidonate mobilization, protein phosphorylation, and inositol phosphate formation. Zymosan A also raises cyclin D2 levels suggesting a role for the latter in macrophage activation besides proliferation. It potentiates acute liver damage after galactosamine injection suggesting that certain types of non ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
