The Parasexual Cycle in Yeasts of the Genus Metschnikowia

Publisher Website
Google Scholar
Abstract
SUMMARY Previous workers have reported the sporadic occurrence of haploid cells or zygotes in asporogenous cultures of Metschnikowia pulcherrima and M. reukaufii (formerly classified as Candida species). Such observations, the “protosexual” cycle described by Wickerham in 1964 included, may be explained in terms of the parasexual cycle previously clearly defined only in filamentous fungi. For several reasons, principally the uninucleate nature of yeast cells and the life cycles characteristic of the above species, expression of the parasexual cycle is much more frequent and more readily detected in these yeasts than in filamentous fungi. Evidence is presented that in some nonsporulating, diploid cultures of Metschnikowia, haploid cells may arise with a frequency of about one in each 500 diploid cells. Experimental procedures of general applicability are given, and the possible importance of parasexuality in the life cycles of these yeasts is discussed.