Protoplast fusion hybrids of Candida albicans sterol mutants differing in nystatin resistance.

Intraspecific protoplast fusion, induced by polyethylene glycol and Ca2+, was carried out in various pairings between auxotrophic nystatin-sensitive, ergosterol-producing strains of Candida albicans and their nystatin-resistant, ergosterol-less mutants of different origins. Nutritionally-complemented stable heterozygous diploid hybrids were obtained, which proved to be sensitive, semi-resistant or resistant to nystatin as a consequence of complementation or non-complementation for ergosterol biosynthesis. Dominant mutation control of the resistance was not found.