Fig 2.

Altered stoichiometry of RND multidrug efflux pump composition under hypoxic conditions. The expression of the genes (mexA, mexC, and mexE) encoding the linker molecules for the RND multidrug efflux pumps MexAB-OprM, MexCD-OprJ, and MexEF-OprN in P. aeruginosa under normoxia (N) and hypoxia (H) was investigated by real-time PCR. (A and B) ATCC 27853 was grown under N or H for 6 h (A) or 24 h (B). Expression of the mexA, mexC, and mexE genes was detected by real-time PCR. Relative gene expression was normalized and expressed as mexE/mexA and mexE/mexC ratios. Values are means ± standard errors of the means for 3 independent experiments (*, P < 0.05). (C) Clinical P. aeruginosa strains were exposed to N and H for 6 h, and expression of the genes encoding the linker molecules was detected by real-time PCR. Relative gene expression was expressed as mexE/mexA and mexE/mexC ratios. Values are means ± standard errors of the means for 2 independent experiments (*, P < 0.05).