Chemical and enzymatic variation in the cell walls of pathogenic Candida species

Abstract

Cell walls, isolated from seven pathogenic species of Candida, were lipid extracted and fractionated by treatment with ethylenediamine or enzymatically hydrolyzed using chitinase and laminarinase. Two different chitinase preparations were used, one from Streptomyces sp. which had some β-1,3-glucanase activity, and another from Serratia marcescens which did not have glucanase activity. Laminarinase was a commercial preparation. The monosaccharide constituents of whole cell walls and the fractions derived from them were determined qualitatively and quantitatively by gas–liquid chromatography of the products of a mild acid hydrolysis and by the phenol – sulfuric acid assay of the products of a stronger acid hydrolysis. The monomeric constituents of the enzymatic hydrolyses were analyzed using gas–liquid chromatography. Approximately 50% of all walls was soluble in ethylenediamine. Glucose and mannose were the only monosaccharides found in all of the fractions derived from ethylenediamine extraction examined. Similarities among the strains, based upon relative amounts of glucose and mannose, were more apparent than differences, but statistical analyses of the data revealed a general trend of decreasing similarity in the following order, C. albicans and C. stellatoidea, C. tropicalis and C. parapsilosis, and C. pseudotropicalis, C. guilliermondii, and C. krusei. In the enzymatic assays, mannose and glucose were released by laminarinase, whereas glucose and N-acetyl-D-glucosamine or N-acetyl-D-glucosamine alone were released by the chitinases. These assays supported the trend in relationships cited above, with the data being somewhat more definitive.