Soluble and insoluble glucans from different cell types of the human pathogen Sporothrix schenckii

Abstract

The structures of soluble and insoluble glucans from isolated cell walls of yeast, mycelial, and conidial forms of Sporothrix schenckii were compared. Methylation analysis showed the presence of linear structures and did not reveal any qualitative variation of glycosidic linkage type. Periodate oxidation methods demonstrated that soluble and insoluble glucans were chemically very similar in all cell types. Soluble glucans from S. schenckii yeast forms have proportions of 44, 28, and 28% of, (1→3), (1→6), and (1→4) linkages, respectively. Insoluble glucans from yeast forms also contain (1→3), (1→6), and (1→4) linkages but their proportions are 66, 29, and 5% respectively. Proportions of these linkages in the mycelial and conidial glucans were similar to those in yeast glucans. The β -configuration of the d -glucopyranose units was shown by the specific rotations of the soluble glucans or the methylated derivatives of the insoluble ones. It was also determined by enzymolysis of both types of glucan with β -glucanases. The disruptive action of these enzymes on the fibrillar network of walls from all cell types was observed by electron microscopy. 13 C nuclear magnetic resonance spectra of soluble glucans are consistent with the configuration and position of substitution of glycosidic linkages indicated by other methods.