Polysaccharides metabolism

To assess whether Inhibition is due to an inability of the organisms to metabolize the modified polysaccharide or due to the actual toxicity of the products themselves, studies relating the growth in a liquid medium were undertaken. Trlchoderma reesel and Chaetomlnum globosum readily metabolize polysaccharides including cellulose derived from cotton. 

One theory (Doss and Matiar-Vahar 1965) states that gangliosides accumulate in the brain of HD patients, because the ganglion cell has no other way to metabolize polysaccharide fragments except using them for ganglioside synthesis. However, it is unlikely that increased formation of gangliosides would lead to their accumulation in the absence of a simultaneous disturbance of the degrading system or of impairment of a feedback mechanism. 

Cytochemical staining, by a method involving oxidation with periodate and reaction with thiosemicarbazide and osmium tetroxide, has revealed the presence of polysaccharide lamellae on the surface of the cell membrane of Claviceps purpurea.The membranous clusters in vacuolar bodies of the endoplasmic reticulum membranes, tonoplasts, and cytoplasmic membranes are covered with these lamellae. Somatic and metabolic polysaccharides composed of D-mannose and L-rhamnose have been isolated from Certocystic stenoceras and Sporotrichum schenckii , chemical and immunological analyses indicated close similarities in their structures. When pseudoplasmodia of Dictyostelium discoideum were incubated with 2-acetamido-2-deoxy-D-[ H]glucose, the label was incorporated into a polysaccharide in the slime sheath. The incorporated label disappeared... 

Metabolic Functions. Manganese is essential for normal body stmcture, reproduction, normal functioning of the central nervous system, and activation of numerous enzymes (126). Synthesis of the mucopolysaccharide chondroitin sulfate involves a series of reactions where manganese is required in at least five steps (127). These reactions are responsible for formation of polysaccharides and linkage between the polysaccharide and proteins that form... 

Besides water, the diet must provide metabolic fuels (mainly carbohydrates and lipids), protein (for growth and turnover of tissue proteins), fiber (for roughage), minerals (elements with specific metabolic functions), and vitamins and essential fatty acids (organic compounds needed in small amounts for essential metabolic and physiologic functions). The polysaccharides, tri-acylglycerols, and proteins that make up the bulk of the diet must be hydrolyzed to their constituent monosaccharides, fatty acids, and amino acids, respectively, before absorption and utilization. Minerals and vitamins must be released from the complex matrix of food before they can be absorbed and utifized. 

Knee, M., Bartley, I.M. (1981). Composition and metabolism of cell wall polysaccharides in ripening fruits. In Friend, J., Rhodes , M.J.C. (eds.). Recent advances in the biochemistry of fruits and vegetables. Academic Press, New York, 133-148. 

Bioassay for metabolic activity (glycolytic and acid phosphatase activity) of peritoneal-exudative cells after treatment with polysaccharide practions. 

Carbohydrate metabolism in the organism tissues encompasses enzymic processes leading either to the breakdown of carbohydrates (catabolic pathways), or to the synthesis thereof (anabolic pathways). Carbohydrate breakdown leads to energy release or intermediary products that are necessary for other biochemical processes. The carbohydrate synthesis serves for replenishment of polysaccharide reserve or for renewal of structural carbohydrates. The effectiveness of various routes of carbohydrate metabolism in tissues and organs is defined by the availability of appropriate enzymes in them. 

We must give first an outline of the non-metal pathways which we observe in all cells. We start here because we know nothing about their abiotic chemistry but assume that cellular life arose from it. We shall assume that the basic requirement of all metabolism is the energised and catalysed synthesis of polysaccharides, lipids, proteins and nucleic acids. These are polymers (see Table 4.5), formed from monomers, all of which could have always arisen when energy was applied to the... 

In this group we place mainly the neutral bacterial slimes and reserve carbohydrates. They are better defined products than those previously dealt with and as such may of course be regarded as true polysaccharides. Invariably, however, saponification methods are required to rid them of protein residues and to make them water-soluble. The more soluble mold polysaccharides appear to lose their protein constituents by autolytic processes during the longer periods required for mold metabolism. Mold slime production can, however, readily be demonstrated on a solid medium. It is proposed here to give briefly some of the types of structure known in the group. 

Polysaccharide formation may be endocellular, exocellular or capsular. The polysaccharide is usually a normal metabolic product, frequently a major product. Isolation and purification of a bacterial polysaccharide generally involve continued precipitations from a buffered solution, together with electrodialysis or ultrafiltration. 

Although polysaccharide metabolic products of molds and yeasts are not strictly bacterial polysaccharides, they are considered briefly here because of similarities in chemical structure (see also page 191). 

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