FIG 6.

Membrane-targeting antifungals are more active at alkaline pH. (A) Assessing MICs and the zones of inhibition (white values) of membrane-targeting drugs (amphotericin B [AMB], fluconazole [Fluc], and pyrifenox) on wild-type cells grown on YPD or alkaline (YPD pH 8) medium. Measurements were taken after 5 days of growth for AMB and pyrifenox and 3 days of growth for Fluc. All plates were incubated at 30°C. (B) MIC of AMB for wild-type and the sre1Δ mutant C. neoformans strains grown under increasingly alkaline conditions. MIC was determined after 48 h of growth at 30°C by broth microdilution. MIC values could not be determined (N/A) for sre1Δ mutant at pH >6 due to the inability of this strain to grow under these more alkaline conditions.