FIG 3.

Growth-promoting activity assay results. (A to D) The apo-forms of acinetobactins were used to treat A. baumannii ATCC 19606 (A) ΔbasD, (B) ΔbauA, (C) ΔbasDΔbauA, (D) ΔbauB, and (E) ΔbauD under iron-deficient conditions (LB medium with 200 μM DP). In addition, the respective mutants under iron-deficient conditions were treated with the holo-forms of acinetobactins (F to J). These assays were conducted on a 200-μl scale by using 96-well transparent microplates. After incubation of the strains at 37°C for 24 h (apo-forms) or 12 h (holo-forms), the absorbance at 600 nm was recorded by using a microplate reader. The time course growth curves over 24 h can be found in Fig. S3. Error bars represent the standard deviations of independent triplicate experiments. Statistical significance was assessed by two-way ANOVA tests (ns, not significant; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001).