Figure 7. Excess dietary Mn protects against reactive oxygen species in vivo.

WT mice were fed high Mn or control diet and infected with S. aureus or ΔsodA/M for four days. (A) Heart bacterial burdens. N = 10 (control diet groups), 8 (high Mn diet groups). (B) Heart bacterial burdens of ΔsodA/M following treatment with anti-Ly6G antibody or isotype control. N = 5 (control diet, isotype group) or 4 (other groups). (C) Growth of S. aureus WT or ΔsodA/M in 1 mM paraquat and 1 mM MnCl₂. OD₆₀₀ was measured at 8 hours. Data are combined from three independent experiments. (D) Growth of 9 clinical endocarditis isolates in 5 mM paraquat and 1 mM MnCl₂. Each symbol represents an independent bacterial isolate. OD₆₀₀ was measured at 21 hours. (E) Bacterial survival (% growth control) after 1 hour incubation of S. aureus with human neutrophils +/− 1 mM MnCl₂. Apocynin treatment was used to inhibit neutrophil NADPH oxidase. N = 14 donors. (A–B, D) Bars depict median and interquartile range. (C, E) Bars depict mean and SEM. *P < 0.05. ** P < 0.01. *** P < 0.001 by ANOVA with Tukey’s multiple comparisons (A–C), repeated measures ANOVA with Tukey’s multiple comparisons test (D), or repeated measures ANOVA with Sidak’s multiple comparisons (E). See also Figures S5 & S6.