FIG. 2.

Fe(III)-reducing activities of whole cells (A) and high-MW (B) and low-MW (C) culture supernatant fractions of cultures grown in the presence of 5 μM Df (iron limited) or 10 μM FeSO₄ (iron replete). Ferric reduction was assayed with BPDS as the chromogenic Fe(II) chelator. The averages of triplicate wells from a representative experiment are shown; standard deviations are indicated by bars. Similar results were obtained in three independent experiments.