Fig. 8
Cells with stable bulges can resume growth after antibiotic removal. a Time-kill analysis of the wild type and stable bulging mutants. Cefsulodin was added to a final concentration of 100 μg/ml at time 0. Error bars correspond to the mean ± standard deviation estimated from n = 3 experiment replicates. b Micrographs show the successful recovery of ΔargO bulging cells on antibiotic-free LB-agarose pads. Cells were collected after 1 h of exposure to cefsulodin. Scale bar corresponds to 10 μm. c Bars show the distribution of single-cell outcomes of regrowth in antibiotic-free medium for the stable bulging mutants. For each mutant, we recorded morphological changes in 30–45 cells. The outcome was determined manually from the colony morphology after 3 h of regrowth in antibiotic-free medium. Cells that lysed were put in the category of lysed, cells that could not revert back to rod-shaped cells were put in the category of misshapen and the cells that could form a colony of rod-shaped cells were put in category of recovered. d Micrographs show ΔpgpA bulging cells that could not successfully revert back to rod-shaped cells or underwent lysis on antibiotic-free LB-agarose pads. Scale bar corresponds to 10 μm. e Micrographs show the morphology of cells of stable bulging mutants after 1 h of cefsulodin (CFS) treatment with and without EDTA (1 mM) in the medium. Addition of EDTA in conjunction with cefsulodin abolishes stable bulge formation in the mutants. Scale bar corresponds to 20 μm. Micrographs in b, d, and e are representative of 1 experiment. Source data for a, c are available in Supplementary Tables 3–4
