FIG. 2.

Uptake of ⁵⁹Fe-siderophore complexes by B. cepacia K56-2 and K56orbA::tp. (A) Uptake assays were initiated by the addition of ⁵⁹Fe-ornibactins; (B) uptake assays were initiated by the addition of ⁵⁹Fe-SA. Samples of 1 ml were removed at intervals, and the amount of ⁵⁹Fe accumulated was determined from a standard curve. Values are means ± standard deviations of triplicate assays. These experiments were repeated at least three times with similar results.