Structural organization of the components of the cell wall from Candida albicans

The organization of the components of the cell wall from Candida albicans was studied by means of sequential treatment with hot SDS, anhydrous ethylenediamine (EDA) and lytic enzymes, followed by chemical and microscopic analyses of the different separated fractions. The EDA-insoluble fraction retained the original morphology of the wall, which was destroyed by beta-glucanase, but not by chitinase treatments. Staining with fluorescent lectins revealed distinct distributions of mannoproteins, glucans and chitin in the wall. Amino acid analysis of SDS-extracted walls, and the EDA-soluble and -resistant fractions gave similar results, with seven amino acids making up about 70% of the total protein weight. Treatment of the EDA-insoluble fraction with Zymolyase or chitinase released fragments of variable size whose susceptibility to these and other hydrolases suggests that they are made of glucan, chitin and mannan oligomers associated with proteins. Treatment of the Zymolyase-insoluble residue with chitinase released a series of low-molecular-mass oligomers made of neutral sugars, GlcNAc and amino acids, mainly lysine. It is suggested that they represent fragments of the core making up the scaffold of the cell wall of the fungus.