Effects of antifungal drugs on proliferation signals in Candida albicans.

The sensitivity of Candida albicans to antifungal drugs when cultured under aerobic and anaerobic conditions was measured. Ciclopirox olamine and siccanin were more effective under aerobic than under anaerobic conditions. Terbinafine, neticonazole and amphotericin B showed the same antifungal activity under both aerobic and anaerobic conditions. None of these antifungal activities were affected by the pH conditions. Terbinafine inhibited the elongation of hyphae, while neticonazole and amphotericin B induced proliferation of the yeast form. The expression of RAS1, EFG1 and CPH1 mRNAs was inhibited by these drugs. These results suggested that the inhibition of hyphal formation might be caused by disruption of the RAS1-signal pathway.