Fig. 5.

ptsI deficiency associated with a metabolic flux shift and down-regulation of ATP synthesis. (A) Effects of a deficiency in ptsI on ciprofloxacin-induced (5× MIC) expression of genes involved in metabolic flux (glycolysis, PPP, TCA cycle) and oxidative phosphorylation. Shown are genes up-regulated (orange; number in parenthesis represents log₂ increase) or down-regulated (blue; number in parenthesis represent log₂ decrease) by greater than twofold in the indicated metabolic pathways, as revealed by RNA-seq analysis. (B) Deficiency in ptsI restricts the increase in cellular ATP level stimulated by phenol or ciprofloxacin. Wild-type and ΔptsI-mutant cells were treated with 3.5 mg/mL phenol for 20 min or 5× MIC ciprofloxacin for 60 min. ATP levels were determined and expressed as pmol/10⁶ cells. Data are averages of three biological replicates; error bars indicate SEM. (C) Suppression of ciprofloxacin-mediated up-regulation of ATP synthase genes by a deficiency in ptsI. Ciprofloxacin treatment at 5× MIC for 90 min up-regulated all eight genes encoding ATP synthases in wild-type cells; a deficiency in ptsI inhibited all up-regulation and suppressed atpC expression, as revealed by RNA-seq analysis. Panel shows comparisons; far right bar shows color scale. See SI Appendix, Fig. S7 for supporting information.