Characteristics of evolved mutants. (A) Activity of a GFP transcriptional reporter for the mexE promoter as a function of time. Activity is measured as fluorescence level divided by optical density. Results are shown for six genotypes grown in casamino acid medium; mexT+ (blue), ΔlasR (red), ΔlasR;psdR- (orange), mexT- (purple); ΔlasR; mexT- (green) and ΔlasR;psdR-;mexT- (cyan). (B,C) growth in casein medium of seven relevant genotypes. Growth was measured as the ratio between cell counts after and before the indicated incubation intervals using flow cytometry. Shown are results for (B) ΔlasR background strains inoculated at an initial optical density of 0.1, (C) lasR+ background strains, inoculated at an initial optical density of 0.01. Error bars represent standard error of three or more independent repeats on different days. Exact genotypes are provided in Supp. Tables S1,S2. NS – Non Significant. * – p-value<0.05, ** – p-value<10-3