FIG 4.

OxyR2-AhpC effects on prxA expression. (A) Confirming RNA-seq data using P_prxA-luxCDABE reporters. The wild type and the ΔoxyR2 mutant containing the P_prxA-luxCDABE transcriptional fusion plasmids were grown standing in AKI medium at 37°C for 4 h followed by shaking for 1 h. H₂O₂ (50 μM final concentration) was added to indicated cultures, and cultures were shaken at 37°C for 2 h. Luminescence was then measured and reported normalized to OD₆₀₀. (B) OxyR2 effects on ahpC and prxA expression in E. coli. DH5α containing pBAD24 (vector control) or pBAD-oxyR2 and P_ahpC-luxCDABE or P_prxA-luxCDABE reporter plasmids was grown in LB containing 0.3% arabinose until reaching an OD₆₀₀ of 0.4. Luminescence was then measured and normalized to OD₆₀₀. (C) prxA expression in different V. cholerae mutants. The wild type and different mutants indicated containing the P_prxA-luxCDABE plasmids were grown under the conditions described for panel A (without H₂O₂). Luminescence was then measured and reported normalized to OD₆₀₀. Data shown represent the mean and standard deviation from three biological replicates. *, P value < 0.05; ns, no significance; LU, luminescence unit.