FIG. 7.

Requirement for mitochondrial function in apoptosis induced by PHS. (A) Rapid production of ROS in nimT23 G₂-arrested cells after PHS treatment. nimT23 mutant spores were germinated at 42°C for 4 h and then loaded with DHR123 (5 μg/ml) for 2 h before PHS treatment. Shown in the lower panel are cells stained with DHR123 in the presence or absence of PHS for 20 min. DIC, differential interference contrast microscopy. (B) Scavenging of ROS by TMPO has no effect on DNA condensation induced by PHS. nimT23 mutant spores were germinated in the absence or presence of 2 μM TMPO at 42°C for 4 h and then loaded with DHR123 as described for panel A before the addition of various concentrations of PHS for 30 min. Cells were fixed and stained with DAPI to visualize DNA. Micrographs of corresponding cells show DAPI and DHR123 staining. (C) Inhibition of mitochondrial function by oligomycin prevents DNA condensation induced by PHS. nimT23 mutant spores were germinated for 4 h at 42°C in the presence or absence of 10 or 20 μM oligomycin and then loaded with DHR123 for 2 h before PHS treatment as described for panel B. Cells were fixed and stained with DAPI. Micrographs of corresponding cells show DAPI and DHR123 staining. Bars, 5 μm.