Fig. 5

Effects of the overexpression of wild-type and mutant AtpC proteins on the viability of E. coli after acid shock. Acid shock and a viability assay were carried out using E. coli expressing an empty vector (a) or wild-type (b) or mutant atpC gene (c). X- and Y-axes show the dilution factor and treatment time, respectively. Relative survival rates of E. coli expressing wild type (black bars) and mutant atpC gene (white bars) are expressed in colony-forming units (CFUs) (d). Error bars indicate standard deviations (n = 4)