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Transfer RNAs Mediate the Rapid Adaptation of Escherichia coli to Oxidative Stress

Fig 6

Higher tRNA concentrations improve adaptation under oxidative stress.

(A) Cell viability testing results obtained using the PI staining method. E. coli BL21(DE3) cells carrying the empty vector pBAD33 and the pRIL plasmid were tested. A histogram showing cells under 0.5 mM H2O2-induced oxidative stress for 15 min was prepared. Cells grown under normal conditions were used as a positive control, and cells killed by incubation at 65°C for 15 min were used as a negative control. (B) Growth rate constants of E. coli BW25113 and BL21(DE3) carrying the pBAD33 and pRIL plasmids, under normal condition. The values shown are the mean ± SD. (C) Growth rate constants of E. coli BW25113 and BL21(DE3) carrying the pBAD33 and pRIL plasmids, under oxidative stress. The actual growth curves of BL21(DE3) carrying these two plasmids are shown respectively. The red line is the moving average observed over 5 min. (D) Cell growth-rate constant under harsh oxidative stress (~1–2 mM H2O2). A negative growth rate constant represents the occurrence of cell death. The data shown are the mean ± SD. (E) The growth-rate constant of E. coli BW25113 cells carrying the pBAD33 and pRIL plasmid, cultured in the presence of different concentrations of ciprofloxacin.

Fig 6

doi: https://doi.org/10.1371/journal.pgen.1005302.g006