Fig 2.

Effect of HGA and synthetic HGA-melanin on iron uptake by L. pneumophila 130b. Wild-type (WT) strain 130b (A), feoB mutant strain NU269 (B), and lly mutant strain NU408 (C) that had been grown in deferrated CDM and then resuspended in buffer were mixed with ⁵⁵FeCl₃ in the presence of PBS (white bars), synthetic HGA-melanin (stippled bars), unpolymerized HGA (bars with diagonal lines), or vitamin C (hatched bars), and after 0, 60, and 120 min of incubation, the levels of intracellular radiolabeled iron were determined. The data represent the means and standard deviations obtained from triplicate samples. In panels A and C, HGA, synthetic HGA, and vitamin C resulted in significantly greater levels of iron uptake relative to the level for the PBS control (***, P < 0.001).