FIGURE 1: Filamentous C. albicans cells are more resistant than blastospores to AMB-induced programmed cell death. Exposure to amphotericin B leads to the generation of reactive oxygen species (ROS) and to caspase activation in C. albicans cells. Representative confocal scanning laser fluorescence images of wild-type SC5314 C. albicans cells treated with 8 μg/ml AMB for 3 hours in YPD. Staining with dihydrorhodamine 123 (DHR123) confirms the presence of ROS (A) and with the FLICA assay for activation of intracellular caspases (B). Error bars indicate standard deviations for trials with at least three independent cultures, where at least 300 cells were counted for each trial. No FLICA positive cells were observed in the no drug controls. A single asterisk indicates statistical significance (p < 0.05) as compared to treated controls. Statistical significance was determined with the unpaired Student’s t-test. Scale bar: 50 μm. Viability curves compare survival of the following cells exposed to AMB: (C) wild type blastospores and wild type filaments induced using 10% FBS; (D) wild type blastospores and wild type filaments induced using 0.5 g/l GlcNAc; (E) ΔΔefg1/efg1 cph1/cph1 cells in YPD and ΔΔefg1/efg1 cph1/cph1 cells following filamentous induction in YPD + 10% FBS, and (F) ΔΔflo8/flo8 cells in YPD and ΔΔflo8/flo8 cells following filamentous induction in YPD + 10% FBS. Note that after 3 hr, cells cultured in rich media without any drugs were able to grow and to divide, hence the relative viability levels that are greater than 100%. Error bars indicate standard deviations for trials with at least three independent cultures. A single, double, and triple asterisk indicates a significance of p < 0.05, p < 0.005, and p < 0.0005, respectively, as compared to treated controls. Statistical significance was determined with the unpaired Student’s t-test.