Polysaccharide materials

Vimses are one of the smallest biological entities (except viroids and prions) that carry all the iaformation necessary for thek own reproduction. They are unique, differing from procaryotes and eucaryotes ia that they carry only one type of nucleic acid as genetic material, which can be transported by the vims from one cell to another. Vimses are composed of a shell of proteki enclosing a core of nucleic acid, either ribonucleic acid (RNA) or deoxyribonucleic acid (DNA), that codes for vkal reproduction. The outer shell serves as a protective coat to keep the nucleic acid kitact and safe from enzymatic destmction. In addition to thek proteki coat, some vimses contain an outer covering known as an outer envelope. This outer envelope consists of a Hpid or polysaccharide material. 

Since polysaccharides are the most abundant of the carbohydrates, it is not surprising that they comprise the greatest part of industrial utiliza tion (9,22). Most of the low molecular weight carbohydrates of commerce are produced by depolymerization of starch. Polysaccharide materials of commerce can be thought of as falling into three classes cellulose, a water-insoluble material starches, which are not water-soluble until cooked and water-soluble gums. 

We are greatly indebted to S. J. Angyal, J. E. Courtois, G. E. McCasland, M. Nakajima, and T. Postemak for gifts of the cyclohexanepentols mentioned, and to A. M. Staub and G. Bagdian who provided us with the polysaccharide material from Salmonella typhimurium. 

In the late 1940s Stacey, with the able and enthusiastic assistance of Paul Kent, examined polysaccharide material from Mycobacterium tuberculosis human strain. From heat-killed cells, two stable, serologically specific polysaccharide fractions and a degraded bacterial glycogen were isolated and examined. 

Polysaccharide materials Starch, cellulose, plant gums (arabic gum, tragacanth, karaya, ghatti, guar, locust bean, fruit tree gum) Paper, paint binders, adhesives... 

The following sections discuss in detail the Py-GC/MS of proteinaceous materials, oils and fats, and then briefly plant and animal resins, polysaccharide materials, and beeswax. Particular attention is given to the application of this analytical technique to characterise samples from works of art. At the end of the chapter four case studies are presented. 

Although the pyrolysis of some classes of polysaccharide materials has been studied quite extensively in the food, petrol and tobacco industry, very little has been published specifically on polysaccharide binders (arabic gum, tragacanth gum, fruit tree gum, honey and starch). The pyrolysis of glucane based polymers, especially cellulose, has been studied in detail [6,55], highlighting how anhydrosugars and furan derivatives are the main pyrolysis products, together with one-, two- and three-carbon aldehydes and acids. 

The purification of a pneumococcal polysaccharide may be difficult, and the polysaccharide material is sometimes contaminated by a cell-wall component known as the C-substance. The methods for structural analysis of polysaccharides (which, like several of the pneumococcal polysaccharides, contain amino sugar and uronic acid... 

Many natural materials are porous but also proton-rich such as wood or other plant products. Relaxation of liquids in these materials has features in common with both inorganic matrices and the protein systems discussed above. The class of porous polysaccharide materials used for size exclusion chromatography provides an example one commercial product is Sephadex. The material swells on solvation to form a controlled pore gel. The main application involves excess liquid, generally water, which flows through the gel bed carrying solutes of various size. The large solutes are excluded from the pore interior and elute rapidly while the smaller ones equilibrate with the pore interior and elute later. The solvent generally samples the pore interior as well as the bulk phase. 

Stipe powder of C. comatus (100 g) was extracted three times with 1 L 95% ethanol under reflux for 2 h to remove lipid, and the residue was extracted three times with 2 L distilled water for 2 h at 80 °C with intermediate centrifugation (2000 x g, 15 min). After concentrating the collected aqueous supernatants to 400 mL (reduced pressure at 40 °C), a precipitation was performed with 3 volumes of 95% ethanol. The precipitate was washed with ethanol and acetone, and then dried at 40 C, yielding crude polysaccharide material. Crude polysaccharide material was dissolved in 100 mL 0.2 M sodium phosphate buffer (pH 6.0), and after centrifugation the solution was applied to a DEAE-Sepharose CL-6B column. 

The method was used in studies of a fungal heterogalactan.150 The polysaccharide was subjected to successive tritylation, methylation, detritylation, p-toluenesulfonylation, reaction with sodium iodide, and, finally, reaction with sodium p-toluenesulfinate. The product was then treated with sodium methylsulfinyl carbanion in dimethyl sulfoxide, the product remethylated, and the polysaccharide material recovered by gel chromatography. The polymer was hydrolyzed, and the sugars in the hydrolyzate were analyzed, as the alditol acetates, by g.l.c.-m.s.1 The analysis revealed that —60% of the hexose residues that were unsubstituted at C-6 had been eliminated. As the product was still polymeric, it was concluded that these residues had constituted a part of side chains linked to a main chain of (1 — 6)-linked D-galactose residues. 

Isolation of Plant Cell Walls and Fractionation of Cell Wall Polysaccharides Materials Plant material, fresh and free from bruises and pathogens Ethanol Carrot (for leafy materials optional) Toluidine blue 0 (see recipe) Phloroglucinol-HCl solution (see recipe) Nail varnish or other sealant Iodine in potassium iodide solution (see recipe) Scalpel Double-edged razor blades Watch glass Artists brush, small Compound light microscope with appropriate glass microscope slides and coverslips... 

Carrier properties. Carriers can be shaped and configured as films, fibers, planar surfaces, or spheres. Surface morphology, i.e., surface texture and porosity, can exert a decisive influence as can carrier materials the most important are inorganic materials such as ceramics or glass, synthetic polymers such as nylon or polystyrene, and polysaccharide materials such as cellulose, agarose, or dextran. 

With the pulp used, a very low ozone charge did not significantly increase the carbonyl content, since preferably the residual lignin present in the material was attacked by the oxidant [16]. The progressing degradation of the polysaccharide material upon further oxidation, as reflected by the decreasing Mw, is clearly visible in Fig. 8. 

The results of the measurements of the shape and size of polysaccharides show that few such polymers have been adequately characterized. Relatively little is known of their size in the native state, and the problems concerned with the isolation of these substances, and the preparation of derivatives have not been completely solved. A paramount problem is the avoidance of degradation. Nevertheless, valuable information on the high-polymer characteristics of a number of defined polysaccharide materials has been obtained. Many polysaccharides of known chemical structure have not yet been examined, and the whole field is an attractive one for further investigations. 

A problem but little discussed in the hterature is the possible association of polysaccharide molecules of various kinds with noncarbohydrate molecules. The association can be random, and a direct fractionation would then be impossible. Thus, it has frequently been observed in the authors laboratory that hemicelluloses containing lignin could not be separated into the pure components, but, after further dehgnification, they could be readily fractionated. It is possible that similar comphcations may also occur with other types of polysaccharide, for example, protein- or lipide-polysac-charide complexes. In this connection, it should be noted that the solution obtained on dehgnification of some materials may contain polysaccharide material of particular interest. For instance, the main part of the galactan present in spruce compression wood can be recovered from such a solution. ... 

It was formerly believed that coniferous woods contain a mannan. However, before the polysaccharide containing the mannose residues was isolated in a state of purity, Leech d and Anthis> were able to show that it was a glucomannan, by the isolation of disaccharides containing both glucose and mannose from a hydrolysate of polysaccharide material enriched in the mannose-containing material. This observation was later confirmed by the isolation of pure glucomannans from these woods. - ... 

The sarcolemma consists of a plasma membrane and an onter coat made np of a thin layer of polysaccharide material that contains numerous thin collagen fibrils. At each end of the muscle fibre this outer coat of the sarcolemma fuses with a tendon fibre, and the tendon fibres in turn collect into bundles to form the muscle tendons that then insert into bones. The membrane is designed to receive and conduct stimuli, is extensible and encloses the contractile substance of a muscle fibre. The sarcolemma is attached to the cytoskeleton on its cytoplasmic surface. It invaginates into the c)doplasm, forming membranous tubules called transverse tubules sarcoplasmic reticulum (enlarged smooth endoplasmic reticulum) lies either side of the transverse tubules. The transverse tubules and sarcoplasmic reticulum transmit altered membrane permeability down the tubules and into the muscle. 

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