Table 2.

Endogenous H2O2 activates the OxyR regulon in an ahpCF mutant

StrainaMean β-galactosidase activity (U/mg of protein) ± SD
AnaerobicAerobicAerobic + catalaseb
Ahp+ OxyR+(GSO22)0.03 ± 0.010.03 ± 0.010.03 ± 0.01
Ahp OxyR+(LC70)0.03 ± 0.010.35 ± 0.030.18 ± 0.02
Ahp OxyR(LC74)0.03 ± 0.010.03 ± 0.01NDc
  • a Strains were isogenic and harbored λRS45 (katG::lacZ).

  • b Exogenous catalase (30 μl) was added before the culture was aerated and then every 15 min until it was iced.

  • c ND, not determined.