FIG 4.

Chelation of iron rescues all strains under anaerobic conditions. Cell viability assays were performed with cultures of IB-101 (red), the Δdps mutant (green), the Δbfr mutant (orange c), and the Δdps Δbfr mutant (purple). Cultures were grown to an OD of 0.3 and then split. Half was treated with 2,2′-dipyridyl (300 μM) (solid lines), and half was not treated (dashed lines). All cultures were then challenged with 500 μM tBOOH, and the number of CFU per milliliter was determined over time. Data are averages from three biological replicates performed over two independent experiments, with standard deviations.