FIGURE 5.

Exogenous Mn-SOD does not protect sodA from streptonigrin-dependent stress. ML23/pBBE22 and sodA strains were inoculated into BSK-II medium containing dimethyl sulfoxide (control, DMSO), streptonigrin (10 μg ml⁻¹, SN) or streptonigrin plus Mn-SOD (75 units ml⁻¹), and growth was monitored over time by cell enumeration with dark field microscopy. The data are from separate experiments from two with separate 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 significance between ML23/pBBE22 + SN and ΔsodA/pBBE22 + SN (p < 0.01).