FIG. 3.

Growth of B. anthracis Sterne (34F₂), the ΔsodA1, ΔsodA2, and Δasb mutants, and the ΔsodA1 ΔsodA2 double mutant in untreated rich (LB) broth (A) and in the same medium chelated with 300 μM (B) or 400 μM (C) 2,2′-dipyridyl. The Δasb mutant displayed the most severe growth defect in chelated medium, while the ΔsodA1 mutant and ΔsodA1 ΔsodA2 double mutant showed consistent attenuation at both 2,2′-dipyridyl concentrations. The Δbac strain displayed growth identical to that of the Sterne parental strain (data not shown). Results from one experiment representative of three independent experiments displaying the same trend are shown.