Skip to main content
. 2018 Oct 5;13(10):e0205036. doi: 10.1371/journal.pone.0205036

Fig 4. AmgRS-dependent AG-inducible mexAB-oprM expression.

Fig 4

(A) mexA expression was assessed in log-phase cultures of WT P. aeruginosa strain K767 and its ΔamgR (strain K3159) and ΔamgS (strain K3583) derivatives following exposure to the MIC of PAR (K767, 256 μg/ml; K3159, 16 μg/ml; K3583, 16 μg/ml) for 30 min using qRT-PCR. (B) mexA expression was assessed in log-phase cultures of P. aeruginosa strains K767 (WT; AmgR+) and K3159 (ΔamgR; AmgR-) exposed to the MIC of the indicated antimicrobials (-, no antimicrobial; NEO, neomycin; GEN, gentamicin; KAN; kanamycin) using qRT-PCR. Antimicrobials were used at: NEO, 64 (K767) and 4 (K3159) μg/ml; GEN, 2 (K767) and 0.5 (K3159) μg/ml; KAN, 128 (K767) and 16 (K3159) μg/ml. (C) mexA expression was assessed in strains harbouring WT (K767) and mutant (K3288, AmgSV121G; K3249, AmgSR182C) amgS genes using qRT-PCR. (D) armR and PA3720 expression was assessed in log-phase cultures of P. aeruginosa strains K767 (WT), K3159 (ΔamgR), and K3583 (ΔamgS) exposed to the MIC of PAR for 30 min using qRT-PCR. Expression in all cases was normalized to rpoD and is reported relative to the untreated K767 strain (fold change). Values are means ± SEMs from at least three independent determinations, each performed in triplicate. t-test: *, P < 0.05; **, P < 0.01; ***, P < 0.001.