Fig 4.

H₂O₂ treatment increases the promoter activity of lukAB. (A) PlukAB luminescence values after a 1-hour treatment with 0 or 0.1 mM of H₂O₂ in wild-type JE2, perR::bursa, and saeR::bursa. The results shown are from two independent experiments each performed with 10 colonies of each strain (n = 20). Statistical analysis was performed using unpaired t-tests with Welch’s correction to determine the statistical significance of 0.1 mM H₂O₂ treatment. Error bars indicate SEM. (B) CFUs per milliliter were calculated by plating the bacteria after exposure to H₂O₂ for 1 hour. The results shown are from two independent experiments each performed with two colonies for each strain (n = 4). Statistical analysis was performed using unpaired t-tests with Welch’s correction to determine the statistical significance. Error bars indicate SEM. (C) PlukAB luminescence values after treating bacteria with various concentrations of H₂O₂ for 1 hour. The results shown are from eight independent experiments each performed with six colonies of each strain (n = 48). Statistical analysis was performed on average luminescence per experiment using unpaired t-tests with Welch’s correction to determine the statistical significance of mutants compared to wild-type JE2 at each concentration. Error bars indicate SEM. ^*P ≤ 0.05; ^**P ≤ 0.01; ^***P ≤ 0.001; ^****P ≤ 0.0001.