Fig. 3.

Cr-DFO/FO uptake assay in vivo. The cells of TC129 (A) or TC128 (B) were incubated in iron-limited minimum medium. After 2 μM DFO had been added and the cells had been incubated for 15 min, Cr-DFO (1 or 2 μM) and purified FO (0, 0.2, 0.5, or 2 μM) were added to the culture. After 0-, 20-, 40-, 70-, and 120-min incubation, the cells were harvested and Cr amounts in the whole cells were measured by ICP, as described in Materials and Methods. The optical density at 600 nm of the cultures after 0- or 120-min incubation was 1.2–1.4 (TC129 after 0-min incubation), 1.2–1.3 (TC128 after 0-min incubation), 1.8–2.0 (TC129 after 120-min incubation), and 1.8–1.9 (TC128 after 120-min incubation). The Cr-DFO and FO concentrations used with 2 μM DFO are as follows; 2 μM Cr-DFO (■), 2 μM Cr-DFO and 2 μM FO (1:1) (▲), 2 μM Cr-DFO and 0.5 μM FO (4:1) (♦), 2 μM Cr-DFO and 0.2 μM FO (10:1) (●), 1 μM Cr-DFO (□). Data are the average of two independent experiments. Bars indicate the SEs.