Hans O. Bouveng

Polysaccharides elaborated by Armillaria mellea(tricholomataceae) : Part II. Water-soluble mycelium polysaccharides

Abstract Cultures of Armillaria mellea , with D -glucitol as the carbon source, have been examined for content of water-soluble polysaccharide. Of the complex mixture obtained, two components have been isolated and structurally examined. The first has been shown to be a xylomannan having a backbone of α(1→3)-linked D -mannopyranose residues, every second to third of which is substituted in the 4-position by a 4- O -α- D -xylopyranosyl- D -xylopyranose residue. The second polysaccharide contains D -galactose, D -mannose, L -fucose, and 3- O -methyl- D -galactose, in a molecular ratio of 6:1:2:2. Structural features include a main chain of α-(1→6)-linked D -galactopyranose residues, substituted in the 2-position by single L -fucopyranose residues or by 3- O -α- D -mannopyranosyl- L -fucopyranose and 6- O -(3- O -methyl-α- D -galactopyranosyl)- D -galactose residues.

Methods in Structural Polysaccharide Chemistry

Publisher Summary This chapter discusses newer methods used in polysaccharide chemistry. In favorable cases, fairly pure polysaccharides can be obtained directly from the raw material by suitable extraction methods. Thus, xylans are easily prepared by extraction of grasses and hardwoods with alkali; and fairly pure cellulose is found in the residue left after drastic extraction of several plant-materials. Fractional precipitation or dissolution of polysaccharides (and polysaccharide acetates or nitrates), either by changing the solvent composition, pH, or temperature, is generally of only limited application, except for the removal of extraneous material, because of the tendency to coprecipitation and occlusion of other polysaccharides. The usual way of determining the sugar residues present in a polysaccharide is to hydrolyze the material and separate the sugars obtained by paper or column chromatography. The methylation technique is of outstanding importance in structural polysaccharide chemistry. The procedure involves the preparation of the exhaustively methylated polysaccharide, hydrolysis to a mixture of monomers, and the separation, identification, and quantitative estimation of the components of this mixture; the original points of substitution will correspond to the unsubstituted hydroxyl groups in these monomeric methyl ethers.