FIG 4.

Selection for acrA⁺ in the presence of salicylate, bile acids, and CCCP. The selection rate is given by log₂(ΔyhdN::kanR/ΔacrA::kanR)/day. The slopes were calculated over days 0 to 3 of testing. Significance was determined as for Fig. 3. (A) Conditions include LBK-PIPES pH 6.8 alone (n = 12), with 0.15% bile acids (n = 20), with 6 mM salicylate (n = 12), with 0.15% bile acids and 2 mM salicylate (n = 12), with 0.15% bile acids and 1.0% ethanol (n = 12), and with 0.15% bile acids, 1.0% ethanol (n = 12), and 10 μM CCCP (n = 12). (B) Conditions include LBK-PIPES pH 6.8 alone (n = 12), with 0.15% bile acids (n = 12), with 4 mM salicylate (n = 12), and with 0.15% bile acids and 2 mM salicylate (n = 16). The daily growth cycle included 100-fold dilution in unbuffered LBK pH 2, with incubation for 2 h. Then, the cultures were diluted 10-fold in the appropriate competition medium adjusted to pH 7.0, yielding a final pH of 6.8.