Lipids of dermatophytes. III. Sterol-induced changes in the lipid composition and functional properties of Epidermophyton floccosum.

Sterol supplementation, alone or in the presence of cerulenin, resulted in an increase in the total sterol content of Epidermophyton floccosum. While the total phospholipid levels of E. floccosum exhibited only marginal changes with sterol supplementation, the fatty acid profiles of these phospholipids were highly varied. In the presence or absence of cerulenin, the oleic acid content of phospholipids were increased significantly by cholesterol supplementation, whereas linoleic acid levels were enhanced by ergosterol supplementation. These variations resulted in higher unsaturated/saturated phospholipid fatty acid ratios in sterol-supplemented cells. The uptake of labeled amino acids (aspartic acid, lysine, glycine) was influenced by sterol supplementation. Alterations in the number of binding sites for the membrane probe, 1-anilino-naphthalene-8-sulfonate (ANS), were seen based on Scatchard plot calculations. The results indicate a correlation between sterol-induced changes in membrane lipid composition and function.