FIG. 2.

Desferrichrome-⁵⁵Fe and RL1194-⁵⁵Fe uptake in PAD07 and PA0470. (A and B) PAD07 or PA0470 (ΔFiuA) cells at an OD₆₀₀ of 3 were incubated for 10 min in 50 mM Tris-HCl (pH 8.0) buffer. Transport assays were started by adding 300 nM ferrichrome-⁵⁵Fe (A) or RL1194-⁵⁵Fe (B) (PAD07, ○; PA0470, □). Aliquots (100 μl) of the suspension were removed at different times and filtered, and the retained radioactivity was counted. The experiment was repeated in the presence of 200 μM CCCP (PAD07, •; PA0470, ▪). (C) PAD07 cells at an OD₆₀₀ of 3 in 50 mM Tris-HCl (pH 8.0) buffer were incubated in the presence of 300 nM ferrichrome-⁵⁵Fe (•). The experiment was repeated in the presence of 200 μM CCCP (○), 900 nM RL1194-Fe (▪), or 3 μM RL1194-Fe (□). The experiments were repeated three times with comparable results.