Fig. 2: The bactericidal effect is not linked to changes of TET intracellular concentration. | Nature Communications

Fig. 2: The bactericidal effect is not linked to changes of TET intracellular concentration.

From: Bactericidal effect of tetracycline in E. coli strain ED1a may be associated with ribosome dysfunction

Fig. 2

a Growth curves of two E. coli strains K-12 (black) and E. coli ED1a (red). The profiles show almost identical growth of the two strains. Timepoint 0 indicates the cells at exponential growth phase chosen for treatment with antibiotic in subsequent experiments. Source data are provided as a Source Data file. b The ability of cells to double in presence of TET assessed through the optical density measurements of cultures in exponential growth phase in LB (continuous lines) or in LB containing 8 μg/ml, (2X MIC) TET (dashed lines). The cells of both strains were unable to double in presence of TET. Source data are provided as a Source Data file. c Viability of cells treated with 8 μg/ml, (2X MIC) TET as in (b) assessed by counting colony-forming units (CFU) on LB (plates). The values and error bars represent averages ± two standard deviations for three independent biological replicates for each condition (of three independent measurements at every timepoint of every sample). Source data are provided as a Source Data file. d Intracellular TET concentration of cultures exposed to different TET concentrations (0−64 μg/ml) for 30 min, measured as absorbance of cell lysates at 365 nm. The concentration in E. coli K-12 (black) is almost two times lower than the E. coli ED1a (red). Statistical significance was calculated using a two-sided unpaired t test of measurements obtained from 3 independent biological replicates. The values and error bars represent means ± standard deviations of three biological replicates. The significance symbols indicate P values: ns for P = 0.2356, * for P = 0.0124, ** for P = 0.0038, **** for P < 0.0001. Source data are provided as a Source Data file. Viability of the E. coli K-12 (e) and ED1a (f) cells exposed to different TET concentrations (0−32 μg/ml) for up to 20 h, assessed by counting colony forming units (CFU) on LB (plates/agar). The survival of E. coli ED1a cells is lower than that of E. coli K-12. The values and error bars represent averages ± two standard deviations of three biological replicates. Source data are provided as a Source Data file.

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