FIG 4.

AmB increases SOD activity and induces distinct SOD responses in ATR and ATS strains. (A) ATR strains (black bars; n = 3) exhibited higher total SOD activity than that of ATS strains (white bars; n = 3) under basal conditions and with AmB treatment (4 h, 1 μg/ml AmB). AmB caused an increase in SOD activity in ATS strains, while ATR SOD activity remained almost constant. SOD activity was determined with a SOD detection kit (Sigma-Aldrich) in these experiments. (B) Representative SOD zymogram of ATS (isolate T77) and ATR (isolate T90) strains, displaying distinct SOD activities under control conditions (co) for the ATS and ATR strains, which were modulated by AmB treatment (1 μg/ml, 4 h). Eighty-microgram aliquots of protein were loaded onto 10% native polyacrylamide gels, and gels were stained for superoxide dismutase activity. The asterisk indicates Cu/Zn-SOD, and the arrows highlight altered protein patterns seen with AmB exposure. (C) SOD zymograms of ATS and ATR strains (n = 3 per group) were evaluated with ImageJ and normalized to those of ATR strains under basal conditions. For all experiments shown, strains were cultured in RPMI 1640 medium at 37°C and 200 rpm. AmB (1 μg/ml) was added for 4 h.