FIG. 5.

zwf and clpP but not ygeO are required for cell death (A) and EDF production (B). (A) E. coli strains MC4100relA⁺Δzwf (Δzwf), MC4100relA⁺ΔygeO (ΔygeO), and MC4100relA⁺ΔclpP (ΔclpP) with or without plasmids pQEzwf (+Zwf) or pQEygeO (+YgeO) were grown to mid-logarithmic phase (OD₆₀₀ of 0.6) as described for Fig. 4. When the cultures reached a density of 2.5 × 10⁸ cells/ml, duplicate samples were removed, and cells containing the plasmids were induced using 1 mM of IPTG and incubated without shaking at 37°C for 10 min. Samples were further incubated without shaking at 37°C with rifampin (10 μg/ml). For the rest of the experiment, see Materials and Methods. (B) Cultures of the E. coli strains described for panel A were grown in M9 with or without ampicillin to mid-logarithmic phase. In order to examine the effect of YgeO or Zwf, these proteins were induced in a manner similar to that of MazF (as described for Fig. 4B). The EDF activity of the collected supernatants was examined as described for Fig. 4B.