Effects of Fur, Hfq, and manganese on the activity of superoxide dismutases. (A) Effects of Fur and Hfq - Cell-free extracts from anaerobically grown cultures (14028s, Δfur, Δhfq, and ΔfurΔhfq) were prepared as described in the Methods. Equal protein (125 μg/ml) was loaded and following electrophoresis the gel was stained for SOD activity. Lane 1 - 14028s; lane 2 - Δfur; lane 3 - Δhfq; lane 4 - ΔfurΔhfq. (B) Effects of Fur and MnCl2 - Cell-free extracts were prepared from anaerobically grown cultures as in (A) except that 1 mM MnCl2 was added to the media. Equal protein (125 μg/lane) was loaded, elecrophoresed, and stained for SOD as in (A). Lane 1, 14028s + MnCl2; lane 2, 14028s + pfur-ha; lane 3, 14028s + MnCl2 + pfur-ha; lane 4, Δfur + MnCl2; lane 5, Δfur + pfur-ha; lane 6, Δfur + MnCl2 + pfur-ha.