Relationship of Nuclear Segregation and Macroconidial Germination in Microsporum gypseum

Abstract

Microsporum gypseum macroconidia germinated at 37 C possessed from one to eight nuclei per germinated spore compartment. The distribution of nuclei per spore compartment was the result of a random packaging of nuclei from the available nuclear population. Partial inhibition of germination by incubation at 25 C or at 37 C in the presence of 10-4 M phenyl methyl sulfonyl-fluoride resulted in an enrichment of germinated spores containing high numbers of nuclei per compartment. The selection for higher nuclear numbers was statistically significant. Compartments possessing high numbers of nuclei appeared to be precommitted to spore germination since they were not sensitive to germination inhibition. The effect of incubation temperature variation on spore germination is discussed with respect to the organism's natural environment.Asexual sporulation in fungi results in the production of uninucleate or multinucleate (or both) spore types (1, 2, 6, 7). The multinucleate spores are characterized by a varying number of nuclei per spore or septated spore unit. Recently, Heisenberg and Cerdac-Olmedo (2) demonstrated that

Isolation and Preliminary Characterization of Developmental Mutants from Microsporum gypseum

“…We previouslysuggested that spore coat proteolysis was an essential event in macroconidial germination (7,8). This investigation was initiated to explore further the relationship of proteolysis to fungal sporulation and spore germination.…”