FIGURE 2.

Deletion of tmRNA reduces lethality of FQs but not of penicillin. (A) Percentage of survival of wt, ΔssrA and TIGR4ΔsmpB (ΔsmpB) strains upon treatment with LVX, MOX and/or penicillin (PEN). Exponentially growing cells were treated with each antibiotic at the concentration and times indicated. Survival was determined as described in Section “Materials and Methods.” (B) Accumulation of ROS in wt and ΔssrA strains upon treatment with 2.5 and 5× MIC of LVX and MOX were measured in the same samples as described in Section “Materials and Methods.” RFU, relative fluorescence units; fluorescence units were divided by the number of viable cells and normalized to time zero and no antibiotic treatment condition. Values (mean ± SD) of at least three independent experiments are shown. The MIC values used were those determined in Table 4.