Cell Wall Structure of Pythium debaryanum

Abstract

Mechanically isolated cell walls of Pythium debaryanum were examined for the presence of cellulose and chitin, and a quantitative study was made of the wall constituents. Polysaccharides, protein, and inorganic constituents accounted for more than 90% of the total wall structure. Over 80% of the wall was polysaccharide, the greater portion of which was glucan. Traces of mannose and hexosamine were present, but chitin was absent. The heterogeneous glucan fraction was composed of cellulose which was microfibrillar and in the crystalline cellulose I form, and a glucan or glucans composed of [beta]-(1[forward arrow]3) and [beta]-(1[forward arrow]6) linkages. The latter was slightly soluble in 1 [image] acetic acid and 1 [image] KOH and appeared amorphous by electron microscopy. It very effectively masked the cellulose microfibrils. The quantity of this glucan material was considerably greater than that of cellulose, as appears to be true in all the Oomycetes which have been examined.