Fig. 1. Growth phenotypes of ΔybeX strain and compensation with single-copy plasmid. (A ) The E. coli ybeZYX-lnt operon chromosomal organization with sigma factors (σ32 and σ24) and promoters (ybeZp and the predicted lntp4). (B ) Dot spot assay of wild-type (WT) and ΔybeX strains, along with the strains harbouring the TransBac library plasmid backbone (WT/pEmpty or ΔybeX /pEmpty), and the ΔybeX strain with the YbeZ, YbeY, or YbeX-expressing single-copy TransBac library plasmid. LB agar plates were incubated at 37°C or 42°C. (C-D ) The stationary phase outgrowth of the wild type and the ΔybeX strains in liquid LB medium. Panel C shows the OD600 signal, and panel D shows the Alamar Blue fluorescence reading. Both signals are normalized to one. Individual measurements from independent experiments, each presented as the mean of three technical replicates, are shown as dots. Curves are modelled with splines, and 95% credible intervals are shown as shaded areas (see Materials and Methods for details). pybeX, pybeZ and pybeY denote the YbeX, YbeZ and YbeY expressing plasmid.