Figure 5. Lack of an effect of catalase on LCM-mediated chlamydiacidal activity.

(A) LCM collected from still cultures of Lactobacillus strains were either untreated or treated with catalase before they were used to treat GFP-L2 EBs for 1 h. Surviving bacteria were quantified as outlined in Fig. 1 legend. Values were averages ± standard deviations of triplicate experiments. Note no statistical differences existed between catalase-treated and untreated samples for LCM from any of Lactobacillus strains. (B) 0.3% H₂O₂ prepared in 0.17 M lactate-NaOH (pH 4.0) was treated with 0.2 mg/ml catalase or control 0.9% NaCl. Remaining H₂O₂ was detected with KMnO₄ titration. Values were averages ± standard deviations of triplicate experiments. Double asterisks signify statistically significant difference (P<0.01) in the amounts of H₂O₂ between catalase-treated and non-treated samples, and indicate that the catalase degraded H₂O₂ in the acidic LCM used in (A).