FIG 6.

The ΔtroR strain accumulates significantly increased levels of intracellular Mn and Co, rather than Zn and Cu. The WT, ΔtroR, and CΔtroR strains were grown in TSBS medium to an OD₆₀₀ of 0.6 and supplemented with 4 mM Mn (A), 100 μM Zn (B), 1.5 mM Cu (C), or 1 mM Co (D). The cultures were incubated for another 30 min, and bacterial cells were then collected to measure the metal contents. The metal content was expressed as μg of metal per g of cells (dry weight). The data shown are the means ± SDs from four biological samples.