FIGURE 5.

Deficiency of tmRNA protects from chromosome fragmentation mediated by LVX. (A) Analysis of chromosome fragmentation upon LVX treatment by PFGE. Exponentially growing cultures of R6 (wt), the R6ΔssrA (ΔssrA) mutant, the complemented strain containing the pROM-TM (ΔssrA(ssrA⁺)) and the R6ΔssrA containing the empty vector (ROM), were treated with or without 10× MIC of LVX for 30 min and analyzed by PFGE as described in Section “Materials and Methods.” (B) Chromosomal fragmentation was estimated by quantification of the compression zone (CZ) relative to the intact chromosomal DNA retained in the well. Each value is the mean of at least three independent experiments and the mean values were statistically compared using Student’s t-test (^∗∗P < 0.01). (C) Percentage of survival to 1 h treatment of LVX at 5, 10, or 20× MIC of wt, ΔssrA strains previously incubated with 10 μ/ml of Chloramphenicol (CM) for 10 min. St stands for the MidRange PFG Marker (Biolabs) with size ranges from 15 to 300 Kb. (D) Percentage of survival along the time to treatment with 5× MIC of wt strains previously incubated with 10 μ/ml of CM or 0.3 μ/ml of erythromycin (EM) for 10 min. Survival was determined as described in Section “Materials and Methods.”