DIMORPHISM-ASSOCIATED CHANGES IN PLASMA-MEMBRANE H+-ATPASE ACTIVITY OF CANDIDA-ALBICANS

In situ plasma membrane H+-ATPase activity was monitored during pH-regulated dimorphism of Candida albicans using permeabilized cells. ATPase activity was found to increase in both the bud and germ tube forming populations at 135 min which coincides with the time of evagination. Upon reaching the terminal phenotype the mycelial form exhibited higher H+-ATPase activity as compared to the yeast form. At the time of evagination H+-efflux exhibited an increase. K+ depletion resulted in attenuated ATPase activity and glucose induced H+-efflux. The results demonstrate that ATPase may play a regulatory role in dimorphism of C. albicans and K+ acts as a modulator.