DIMORPHISM AND HAPLOID FRUITING IN CRYPTOCOCCUS-NEOFORMANS - ASSOCIATION WITH THE ALPHA-MATING TYPE

Cryptococcus neoformans is a major opportunistic fungal pathogen in AI DS and other immunosuppressed patients. We have shown that wild-type h aploid C. neoformans can develop an extensive hyphal phase under appro priate conditions, Hyphae produced under these conditions are monokary otic, possess unfused clamp connections, and develop basidia with viab le basidiospores. The ability to undergo this transition is determined by the presence of the alpha-mating type locus and is independent of serotype. The association of the hyphal phase with the alpha-mating ty pe may explain the preponderance of this mating type in the environmen t and the nature of the infectious propagule of C. neoformans.