Studies on the pink, adenine-deficient strains ofCandida albicans

Abstract

Several pink or dark brown mutants of Candida albicans were obtained following exposure of the wild types to ultraviolet irradiation or ethyl methanesulfonate. Unlike the wild types, all the mutants required adenine and in addition the dark brown strain required valine and isoleucine for growth. The mutants accumulated the pigment in the cytoplasm either as localized granules or in a diffused form. They, however, did not differ from their parental strains in size and shape of yeast cells, fermentation and assimilation of sugars. Initially, the pink mutants were more resistant to amphotericin B, but upon passage on agar media for a prolonged period, they became as sensitive as the wild types. The pink strain produced less mycelium in vitro and in vivo, and were less virulent for mice, but more resistant to ultraviolet irradiation than the wild types.