Fig. 4: RtcB is involved in the cellular response of E. coli bacteria to sub-inhibitory concentrations of Tetracycline.
From: Heterogeneity in responses to ribosome-targeting antibiotics mediated by bacterial RNA repair
Brightfield and 6-TAMRA channel overlay images of E. coli BW25113 wild-type cells at mid-exponential phase. A Untreated and (B) treated cells exposed to 1.5 μg/ml tetracycline for 1 hour. Images were acquired using a Leica Stellaris 8 confocal microscope, and overlays of brightfield and 6-TAMRA channels were generated using ImageJ's overlay function. Fluorescent signals detected in the 6-TAMRA channel appear as white spots, corresponding to rtcB-specific fluorescent DNA probes hybridised to rtcB mRNA molecules. Images from the 6-TAMRA channel were analysed using Spätzcells software to determine the total number of rtcB mRNA molecules per cell. C The output data from Spätzcells were used to calculate the mean (μ) and relative frequency of rtcB mRNAs per cell in the population (nWT = 494 and nWT+tet = 509, experiments were performed with three independent biological replicates). D, E The impact of sub-inhibitory concentrations of tetracycline on the speed of translation elongation in presence and absence of rtcB was measured in vivo using FusA-LacZα reporter assays67. Shown is the square root of enzymatic activity over induction time. D Untreated and E treated cells exposed to 1.5 μg/ml tetracycline for 1 hour. Data points represent the mean and standard deviation of 3 biological replicates. The x-intercept indicates the time it takes to translate FusA-LacZα. Source data are provided in the source data file.
