FIG 9.

Decreased Suf function destabilizes intracellular Fe homeostasis. (A) The WT, sufD*, sufD* suf⁺, and fhuC::Tn strains were spot plated on solid TSA medium with and without 900 mM 2,2-dipyridyl. (B) The WT, sufD*, and sufD* suf⁺ strains were plated as top agar overlays on solid TSA, and the zones of growth inhibition resulting from streptonigrin intoxication were measured. (C) The WT, nth::Tn, mutY::Tn, addB::Tn, Δnfu, and Δnfu addB::Tn strains were plated as top agar overlays on solid TSA, and the zones of growth inhibition resulting from streptonigrin intoxication were measured. The data presented in panels B and C represent the averages of biological triplicates with standard deviations. Student t tests (two tailed) were performed on the data; *, P < 0.05 compared to the WT unless otherwise indicated.