Molecular architecture of the hyphal wall of Achlya ambisexualis Raper. I. Chemical analyses

Abstract

Chemical analyses of the hyphal wall of Achlya ambisexualis Raper were done in an attempt to provide a basis for understanding the molecular architecture of the wall. Walls were isolated, purified, and fractionated by differential solubility. The wall and its fractions were then hydrolyzed by acid or enzymes. The resulting hydrolysates were analyzed by paper and gas–liquid chromatography for their neutral sugar content and type of glycosidic linkages. The degree of branching was estimated by periodate oxidation. The only monosaccharide detected was glucose. Three disaccharides, laminaribiose gentiobiose, and cellobiose, were detected, thus indicating β-1,3, β-1,6, and β-1,4 linkages. Acid-soluble β-1,3-glucan with single β-1,6-linked residues represented 40% of the wall. Alkali-soluble glucan, a linear polymer of β-1,3 and β-1,4 linkage with occasional β-1,6 side chains, represented 7% of the wall. Cellulose, as determined by solubility and X-ray diffraction represented 21% of the wall. The insoluble residuum (6%) which remained after these solubilizations had a linkage pattern similar to the alkali-soluble fraction. An insoluble component consisting of glucosamine represented 3% of the wall. Protein comprised 10% of the wall and on hydrolysis gave the full spectrum of amino acids including hydroxyproline. Small amounts of phosphorus were detected.