FIGURE 4: Determination of respiratory activity, ROS and superoxide dismutase activity in strain ISA1307 upon acetic acid treatment.

(A) Comparison of the survival rate of strain ISA1307 cells treated with 300 mM of acetic acid.

(B) Absorbance measurements (480 nm) of formed formazan using the artificial electron acceptor INT (2-p-iodophenyl-3-p-nitrophenyl-5-phenyl tetrazolium chloride) in ISA1307 cells. Bar graphs indicate mean and standard error of the mean (SEM) absorbance (arbitrary units) measured in 2 OD equivalents/sample in six independent experiments.

(C), (D) FACS measurements of superoxide anions using the probe dihydrioethidium and hydrogen peroxide using the probe dihydrorhodamine 123 (DHR) in ISA1307 cells.

(E) In situ determination of superoxide dismutase activities in 300 mM acetic acid – treated and untreated (control) ISA1307 cells. Bar graphs indicate mean and standard error of the mean (SEM) fluorescence/cell (arbitrary units) measured in 25,000 cells/sample in three independent experiments. Significance of the data was determined by two-way ANOVA (*P < 0.05; **P < 0.01; ***P < 0.001).