Growth of rqlI deletion mutants is severely impaired in low oxygen conditions.

(A) A schematic of predicted domains and homology regions of RqlI. (B) WT F11 or F11ΔrqlI were grown either aerobically or microaerobically for 24 h in a modified M9 media, at which point the cultures were titered. Under microaerobic conditions, strains that carried either an IPTG-inducible rqlI expression vector (pCWR16) or the empty vector control (pRR48) were grown in the presence of IPTG. (C) WT F11 or F11ΔrqlI were grown either aerobically or microaerobically, and the cultures were titered at two different time points during exponential phase in order to calculate generation times. (D) The indicated WT and ΔrqlI mutant ExPEC isolates were grown microaerobically for 24 h and titered. Bars indicate mean values ± SEM from three or more independent experiments performed in triplicate. *, P ≤ 0.05; ***, P ≤ 0.001; ****, P ≤ 0.0001; as determined by Student’s t test.