Fig. 3.

Effect of the dione versus quinolone core structure on mutant subpopulation enrichment. Wild-type M. smegmatis was grown to stationary phase and was then applied to agar plates containing the indicated concentrations of the 2,4-dione UING5-207 (open circles) or the cognate fluoroquinolone UING5-249 (filled circles) as a function of the drug concentration that blocks colony formation for 99% of the CFU in the culture (MIC₉₉). The fraction of mutant cells recovered was determined as described in Materials and Methods. Unlabeled arrows indicate the MPC/MIC₉₉ ratio. Similar results were obtained in replicate experiments; the average MPC/MIC₉₉ ratio ± standard deviation was 20 ± 3.3 for UING5-249 and 6 ± 1.6 for UING5-207.