Figure 10. Induction of white-opaque switching by different environmental stimuli in strain WO-1 and czf1Δ, cph1Δ and wor1Δ mutants.
Two independently generated series of mutants were analyzed in each case and the percentage of opaque (black bars) and mixed white/opaque colonies (gray bars) was determined (means and standard deviations from three biological replicates). (A) Induction by anaerobic conditions. White cells from a YPD preculture were diluted 10−5, plated on Lee's medium, and incubated for 2 days at room temperature in an anaerobic jar, followed by incubation under aerobic conditions at room temperature for 7 further days to allow colony development. (B) Induction by ketoconazole. White cells from a YPD preculture were diluted 10−2 in YPD medium containing 50 µM ketoconazole and incubated for 1 day at 30°C without shaking. Appropriate dilutions were then spread on Lee's plates and incubated for 7 days at room temperature. Control cells incubated in the presence of solvent (DMSO) alone showed <3% opaque or mixed white/opaque colonies. (C) Induction by GlcNAc. White cells were grown for 2 days in YPD medium, diluted 10−5, plated on Lee's medium with 1.25% GlcNAc instead of glucose, and incubated for 7 days at room temperature.