Inhibition of cell-wall synthesis in <i>V</i>. <i>cholerae</i> leads to sphere formation.

<p>(A) Kinetics of viable <i>V</i>. <i>cholerae</i> cell counts after cells were exposed to various antibiotics that inhibit cell wall synthesis. Cells were grown to ~ 2–3 x 10⁸ cfu/ml and then exposed to 100 μg/ml of penicillin G (penG), phosphomycin (phos), D-cycloserine (cyc), ampicillin (amp) or no antibiotic (no AB) (T0). Data shown are averages of two independent experiments; error bars represent standard deviation. (B) Images of <i>V</i>. <i>cholerae</i> cells at different time points after exposure to penicillin G from the experiment shown in (A). (C) Morphology of wt exponential phase cells exposed to 100 μg/ml cyc, phos, amp or 1 μg/ml meropenem (mero) for 3 h. (D) Time lapse images of wt cells plated on an agarose pad containing 100 μg/ml pen G. Frames are 5 min apart, scale bar = 2 μm. Arrowheads point to selected blebs. (E) Localization of blebs after exposure to pen G. Three different time lapse series with ~ 40 cells each were obtained as described in (D) and bleb location as the ratio of distance from an arbitrarily chosen pole divided by cell length was measured using ImageJ software. (F) Time lapse images of wt cells stained with the fluorescent D amino acid analogue HADA (50 μM) for 30 min and washed 2 x to remove excess dye prior to imaging on an agarose pad containing pen G. Images were brightness/contrast-adjusted to compensate for photobleaching. Frames are 5 min apart, scale bar = 2 μm. HADA stain is false-colored in red.