[Yeast resistance to polyene antibiotics. II. An analysis of the sterol composition of Saccharomyces cerevisiae yeasts resistant to nystatin].

The recessive yeast mutations nys providing resistance to polyene antibiotics in Saccharomyces cerevisiae are described. The analysis of UV-absorbtion spectra of sterols from cells of different mutants allows to assume that NYS genes control synthesis of ergosterol. The lack of alterations in the sterol composition of the same strains carrying dominant nystatin resistance mutations points to the existence of another mechanisms of resistance to polyene antibiotics, in addition to the sterol mechanism.