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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. In the field of bacteriology, the term polyglucan is used to describe high molecular mass glucans. They are structural polysaccharide consisting of a long linear chain of several hundred to many thousands D-glucose monomers. The point of attachment is O-glycosidic bonds, where a glycosidic oxygen links the glycoside to the reducing end sugar. Polyglucans naturally occur in the cell walls of bacteria. Bacteria produce this polysaccharide in a cluster near the bacteria's cells. Polyglucan's are a source of beta-glucans. Structurally, beta 1.3-glucans are complex glucose homopolymers binding together in a beta-1,3 configuration. Types The following are glucans (The α- and β- and numbers clarify the type of O-gly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oat Beta-glucan
Oat β-glucans are water-soluble Beta-glucan, β-glucans derived from the endosperm of oat kernels known for their dietary contribution as components of dietary fiber, soluble fiber. Due to their property to lower serum total cholesterol and low-density lipoprotein cholesterol, and potentially reduce the risk of cardiovascular diseases, oat β-glucans have been assigned a qualified health claim by the European Food Safety Authority and the US Food and Drug Administration. History Oat 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 discovered in lichens, and shortly thereafter in barley. After joining Agriculture and Agri-Food Canada in 1969, Peter J Wood played an instrumental role in isolating and characterizing the structure and bioactive properties of oat β-glucan. A public interest in oat β-glucan arose after its cholesterol lowering effect w ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curdlan
Curdlan is a water-insoluble linear beta-1,3-glucan, a high-molecular-weight polymer of glucose. Curdlan consists of β-(1,3)-linked glucose residues and forms elastic gels upon heating in aqueous suspension. It was reported to be produced by '' Alcaligenes faecalis'' var. ''myxogenes''. Subsequently, the taxonomy of this non-pathogenic curdlan-producing bacterium has been reclassified as ''Agrobacterium'' species. Extracellular and capsular polysaccharides are produced by a variety of pathogenic and soil-dwelling bacteria. Curdlan is a neutral β-(1,3)-glucan, perhaps with a few intra- or interchain 1,6-linkages, produced as an exopolysaccharide by soil bacteria of the family Rhizobiaceae. Four genes required for curdlan production have been identified in ''Agrobacterium'' sp. ATCC31749, which produces curdlan in extraordinary amounts, and ''Agrobacterium tumefaciens''. A putative operon In genetics, an operon is a functioning unit of DNA containing a cluster of genes under t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echinocandin
Echinocandins are a class of antifungal drugs that inhibit the synthesis of β-glucan in the fungal cell wall via noncompetitive inhibition of the enzyme 1,3-β glucan synthase. The class has been dubbed the "penicillin of antifungals," along with the related papulacandins, as their mechanism of action resembles that of penicillin in bacteria. β-glucans are carbohydrate polymers that are cross-linked with other fungal cell wall components, the fungal equivalent to bacterial peptidoglycan. Caspofungin, micafungin, and anidulafungin are semisynthetic echinocandin derivatives with limited clinical use due to their solubility, antifungal spectrum, and pharmacokinetic properties. Medical uses Drugs and drug candidates in this class are fungicidal against some yeasts (most species of '' Candida'', but not '' Cryptococcus'', '' Trichosporon'', and '' Rhodotorula''). Echinocandins also have displayed activity against ''Candida'' biofilms, especially in synergistic activity with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleuran
Pleuran is an insoluble polysaccharide ( β-(1,3/1,6)-D-glucan), isolated from ''Pleurotus ostreatus''. Pleuran belongs to a group of glucose polymers commonly called beta-glucans demonstrating biological response modifier properties. These immunomodulating properties render the host more resistant to infections and neoplasms. In a study published in December 2010, pleuran demonstrated to have a protective effect against exercise-induced suppression of immune cell activity ( NK cells) in subjects taking 100 mg per day. In another study published in 2011, pleuran reduced the incidence of upper respiratory tract infections and increased the number of circulating NK cells. Pleuran is also being studied as a potential immunologic adjuvant In immunology, an adjuvant is a substance that increases or modulates the immune response to a vaccine. The word "adjuvant" comes from the Latin word , meaning to help or aid. "An immunologic adjuvant is defined as any substance that acts ... [...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 hemicellulose 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] |
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 "ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Structure Of Levoglucosan
A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combined without reacting, they may form a chemical mixture. If a mixture is separated to isolate one chemical substance to a desired degree, the resulting substance is said to be chemically pure. Chemical substances can exist in several different physical states or phases (e.g. solids, liquids, gases, or plasma) without changing their chemical composition. Substances transition between these phases of matter in response to changes in temperature or pressure. Some chemical substances can be combined or converted into new substances by means of chemical reactions. Chemicals that do not possess this ability are said to be inert. Pure water is an example of a chemical substance, with a constant composition of two hydrogen atoms bonded to a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GLUCOSE LG
Glucose is a sugar with the molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using energy from sunlight. It is used by plants to make cellulose, the most abundant carbohydrate in the world, for use in cell walls, and by all living organisms to make adenosine triphosphate (ATP), which is used by the cell as energy. 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 amylose and amylopectin, and in animals as glycogen. Glucose circulates in the blood of animals as blood sugar. The naturally occurring form is -glucose, while its stereoisomer -glucose is produced synthetically in comparatively small amounts and is less biologically active. Glucose is a monosaccharide containing six carbon atoms and an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycosidic Bonds
A glycosidic bond or glycosidic linkage is a type of ether 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 Glycosidic bond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zymosan
Zymosan is a beta-glucan with repeating glucose units connected by β-1,3-glycosidic linkages. It binds to TLR 2 and Dectin-1 ( CLEC7A). Zymosan is a ligand found on the surface of fungi, like yeast. Zymosan is prepared from yeast cell walls 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 nonparenchymal cells other than Kupffer cells Kupffer cells, also known as stellate macrophages and Kupffer–Browicz cells, are specialized cells localized in the liver within the lumen of the liver sinusoids and are adhesive to their endoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleurotus Ostreatus
''Pleurotus ostreatus'' (commonly known the oyster mushroom, grey oyster mushroom, oyster fungus, hiratake, or pearl oyster mushroom). Found in temperate and subtropical forests around the world, it is a popular edible mushroom. Name Both the Latin and common names refer to the shape of the fruiting body. The Latin ''pleurotus'' (side-ear) refers to the sideways growth of the stem with respect to the cap, while the Latin ''ostreatus'' (and the English common name, oyster) refers to the shape of the cap which resembles the bivalve of the same name. The oyster reference may also derive from the slippery texture of the mushroom. Description The Pileus (mycology), cap is broad, fan or oyster-shaped, and wide. In the wild, it ranges from white to gray or brown; the margin is inrolled when young, smooth and often somewhat lobed or wavy. The Trama (mycology), flesh is white, firm, and varies in thickness due to Stipe (mycology), stipe arrangement. The stipe, if present, is up to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
