Isolation and structure of glucan from regenerating spheroplasts of Candida albicans.

Regenerating spheroplasts of Candida albicans formed organized glucan nets in liquid culture. The nets consisted of interwoven microfibrils about 50 nm wide, but of an undetermined length. Partial acid hydrolysis of the polysaccharide showed the presence of chains of beta(1----3)- and beta(1----6)-linked glucose residues, but no intrachain beta(1----3) and beta(1----6) linkages. Periodate oxidation and GLC of the methylated glucan indicated a highly branched polymer (9.5% branch points). Sequential enzymic degradation of the isolated nets confirmed the presence of chains of beta(1----3)- and beta(1----6)-linked glucose residues. Degradation by (1----3)-beta- and (1----6)-beta-glucanase released 23% (w/w) and 30% (w/w) respectively of the carbohydrate as glucose equivalents. The residual material was degraded by chitinase. Equal amounts of N-acetylglucosamine and glucose equivalents were detected in the chitinase hydrolysate, suggesting a possible linkage between glucan and chitin. Our data indicate that the cell wall of C. albicans contains at least two highly branched glucans with predominantly beta(1----3) or beta(1----6) linkages.