FIG 2.
Growth behavior of MSMEG deletion mutants (A to C) and impact of Zur and SmtB on MSMEG zinc tolerance (D to F). (A to C) Growth curve. MSMEGwt (filled circles), MSMEGΔsmtB (A), MSMEGΔzur (B), and MSMEGΔsmtBΔzur (C) mutants (open squares) and the complemented strains (filled squares) were grown in MB. Four growth experiments were performed in duplicate. Statistical analysis for time point 48 h was performed using one-way analysis of variance (ANOVA) (Kruskal Wallis) with a P of <0.0005 (***). (D to F) ZoI assay. MSMEGwt (black bars) and the MSMEGΔsmtB (D), MSMEGΔzur (E), and MSMEGΔsmtBΔzur (F) mutants (white bars) and complemented strains (gray bars) were spread on LB agar. ZnSO4 was applied to filter discs (diameter, 5 mm) at final concentrations of 25, 50, and 100 mM. Shown are the results of three independent replicates (in triplicate). Statistical analysis was performed using one-way ANOVA (Kruskal-Wallis) with P values of <0.05 (*), <0.005 (**), and <0.0005 (***). ns, nonsignificant.