Fig 4.

KatE enhances resistance to extracellular H₂O₂. Shown are percent survivals of Leptospira strains exposed to oxidative stress conditions in the presence or absence of the catalase inhibitor ATZ. (A) L. interrogans serovar Copenhageni; (B) L. biflexa serovar Patoc; (C) L. interrogans serovar Pomona; (D) L. interrogans serovar Pomona katE mutant strain P3; (E) L. interrogans serovar Manilae; (F) L. interrogans serovar Manilae katE mutant strain m69. Results are shown as means of triplicate values from a single experiment. Experiments were performed twice, with similar results. Statistical analyses were conducted by comparing the percent survival at a particular H₂O₂ concentration using the two-tailed Student t test under the following comparative conditions: (i) the presence and absence of ATZ, (ii) L1-130 versus Patoc, and (iii) wild type (L. interrogans serovar Pomona or Manilae) versus mutant (P3 or m69). Standard deviations are indicated, and significant differences between the means (P < 0.0001) are indicated by an asterisk, while the absence of an asterisk indicates no significant difference.