FIG 1.

Growth of L. reuteri is inhibited by H₂O₂ and HOCl. L. reuteri ATCC PTA 6475 was grown anaerobically at 37°C to an A₆₀₀ of 0.3 to 0.4 in MEI-C and then treated with the indicated concentrations of H₂O₂ (A, B, and E) or HOCl (C, D, and F) (n = 3, means ± SDs). A₆₀₀ (A, B, C, and D) or NAD⁺/NADH ratios (E and F) were measured at the indicated times. Student’s t test was used to test differences between growth rates in the first 2 h after stress treatment (divisions per hour) (*, P < 0.05; **, P < 0.01). Two-way analysis of variance (ANOVA) with Holm-Sidak’s multiple-comparison test was used to test differences between normalized A₆₀₀ values for stress-treated cells and untreated cultures, and significant differences for 0.12 mM H₂O₂ and 1.25 mM HOCl stress are indicated (*, P < 0.05; ***, P < 0.001; ****, P < 0.0001). Two-way ANOVA with Holm-Sidak’s multiple-comparison test was used to test differences between NAD⁺/NADH ratios before and after stress treatments, and no significant differences were found.