FIGURE 6.

Manganese exacerbates the toxicity of streptonigrin in sodA. A, ML23/pBBE22 and sodA/pBBE22 were grown in Chelex-treated BSK-II medium containing dimethyl sulfoxide (control, DMSO), 10 μm MnCl₂, streptonigrin (10 μg ml⁻¹, SN), or 10 μm MnCl₂ and SN. Growth was monitored over time. The data are from separate experiments with different batches of medium (n = 3). B, data from A were used to determine the specific growth rate (k, h⁻¹) for each sample. A paired Student's t test was used to determine the significance between ΔsodA/pBBE22 + SN and ΔsodA/pBBE22 + SN + MnCl (p < 0.05).