FIG. 5.

Effect of divalent metals on iron acquisition from pyoverdin (A) and pyochelin (B) by HL-60 cells. Shown is the mean and standard error of the mean (n = 3) concentration of cell-associated ⁵⁹Fe following a 60-min incubation, in the presence of [⁵⁹Fe]pyoverdin (A) or [⁵⁹Fe]pyochelin (B), of control HL-60 cells and cells which had been preincubated with 1 mM divalent metal (indicated on the x axis). Experiments utilizing the trivalent metal Ga were performed as a positive control and are included as a point of reference. ∗, P < 0.05 relative to control. Specific P values relative to control are as follows: Ga, P < 0.05; Cd, P < 0.02; Cu, P < 0.003; Mn, P < 0.2; and Zn, P < 0.05 (A) and Ga, P < 0.0007; Cd, P < 0.003; Cu, P < 0.00005; Mn, P < 0.9; and Zn, P < 0.0007 (B).