FIG 2.

(A) Growth of wild-type (closed circle), fakA mutant (open circles), ackA mutant (closed square), and fakA ackA mutant (open square) strains. An asterisk denotes a significant difference (P < 0.05) for all points after 2 h for wild type (WT) versus the fakA mutant, while # indicates significance for hours 4, 5, and 9 to 12 for the ackA mutant versus the fakA ackA mutant. (B) pH of culture media from panel A. An asterisk denotes a significant difference (P < 0.05) for all points after 2 h for WT versus the ackA mutant, while # identifies differences (P < 0.05) for all points after 2 h, except for the ackA mutant versus the fakA ackA mutant (6 h). (C) Quantification of acetate in the culture media at indicated time points. An asterisk denotes a significant difference (P < 0.05). N.D., none detected. For all panels, data are the averages (n = 3) with standard deviations from representative experiments. All points have error bars, which may be smaller than symbols.