FIG 2.

Total efflux activities of wild-type E. coli BW25113 and efflux mutants JW0452, BW0451, and JW5503 (carrying acrA, acrB, and tolC deletions, respectively) determined in presence and absence of GSH. (A) Representative flow cytometric histograms depicting the extent of intracellular fluorescence due to Hoechst 33342 retention in different bacterial strains in the presence and absence of GSH (n = 3 per group). In each of the histograms, the x axis represents the signal acquired from the FL4 channel, and the y axis represents the count. (B) Bar chart showing the amount of Hoechst 33342 retained inside the bacterial cell (n = 3 per group). Data points show means ± SEM. One-way Analysis of variance (ANOVA) followed by Tukey's posttest was used to determine the statistical significance. *, compared with control (P < 0.01); #, compared with the absence of GSH for a given bacterial strain (P < 0.05).