Fig. 1
Flow cytometry analysis of GFP fluorescence encoded by gfpΔACA reporters. The leaderless mRNA of the ll-gfpΔACA reporter entirely lacks a 5′-UTR, and this reporter construct has the start sequence ATG of the gfpΔACA gene following directly after the promoter region [16, 20]. The canonical mRNA of the can-gfpΔACA reporter comprises a 5′-UTR, which includes a strong ribosome binding site. A Green distributions depict measurements of the E. coli strain TB212 harboring the plasmid pBAD-mazF and the ll-gfpΔACA reporter encoded on a high-copy plasmid. Light grey distributions depict measurements of the strain harboring only the plasmid pBAD-mazF. Here, one replicate is presented, for further results see Additional file 2. Ectopic mazF overexpression from plasmid pBAD-mazF [19] was induced by adding 0.1% Ara in the early exponential phase, at OD600 = 0.18–0.22. Flow cytometry analysis was performed in the early exponential phase, and 2 h [average OD600(uninduced) = 2.45, OD600(mazF-induced) = 0.45] and 6 h after mazF overexpression [average OD600(uninduced) = 4.42, OD600(mazF-induced) = 0.80]. B Normalized GFP fluorescence from the ll-gfpΔACA reporters or C can-gfpΔACA reporters encoded on a high-copy (HC, dark green) or a low-copy (LC, light green) plasmid, measured in different phases of bacterial growth and after adding arabinose (Ara) to induce mazF expression (N = 3 independent replicate cultures). Altogether, the growth of mazF-induced cultures was reduced by 77–86% after 2 h, and by 71–90% after 6 h, compared to the respective uninduced controls, see Additional file 2