Induction of hyphae in cultures of Pityrosporum by cholesterol and cholesterol esters.

The effect of cholesterol and cholesterol esters on Pityrosporum cultures has been studied. A mixture of 0.25% to 2.0% of cholesterol:cholesteryl stearate:glyceryl monostearate (2.0:1.5:2.0) added to Bacto Yeast Morphology Agar plus oleic acid was able to induce hyphae in cultures of both Pityrosporum orbiculare and P. ovale. This result is discussed with respect to the cholesterol effect on cell membranes and to the occurrence of cholesterol and cholesterol esters in the scaling patches of Pityriasis versicolor.