FIG 1.

S. gordonii DL1 has increased survival within macrophages compared to that of S. gordonii SK12. (A) Percent survival of S. gordonii strains DL1 and SK12, with and without endocarditis pathogenic potential, respectively, within RAW264.7 macrophages for 2 h postuptake. The box plot with whiskers shows the 10th to 90th percentiles, and “+” indicates the mean for each strain. (B) Survival of S. gordonii strains DL1 and SK12 in the presence of increasing concentrations of hydrogen peroxide for 30 min. Data shown are means and standard errors. DL1 survived at significantly higher rates than those of SK12 in the presence of both 5 mM and 10 mM H₂O₂. (C) S. gordonii DL1 removes generated superoxide significantly more efficiently than SK12 does, protecting cytochrome c from reduction in the presence of generated superoxide. The graph shows means and standard errors, normalized by setting the positive-control purified superoxide dismutase value at 100%. (D) DL1 and SK12 survival rates after exposure to pH 3 for the indicated times. Data shown are means and standard errors. All data are for a minimum of 4 independent experiments and a minimum of 5 technical replicates per experiment. P values were calculated with unpaired t tests (A and C) or one-way (B) or two-way (D) analysis of variance (ANOVA) with the Sidak multiple-comparison test. n.s., not significant.