Accumulation of 14-methyl sterols and defective hyphal growth in Candida albicans.

Polyene-resistant mutants of Candida albicans accumulating 14-methyl sterols in place of ergosterol and defective in hyphal growth were isolated after ultraviolet mutagenesis. Analysis of revertants showed that the alteration in sterol composition, the inability to grow as hyphae, and the antibiotic resistance had returned to normal simultaneously. In addition, clotrimazole, which caused accumulation of 14-methyl sterols at a subfungistatic concentration, also inhibited hyphal formation but had little effect on yeast propagation. It is concluded that there is an intrinsic rather than a fortuitous relationship between sterol composition and morphogenesis.