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. Author manuscript; available in PMC: 2014 Mar 20.
Published in final edited form as: Bioconjug Chem. 2013 Feb 14;24(3):473–486. doi: 10.1021/bc300610f

Figure 6.

Figure 6

Effect of varying Fe(III) concentrations and presence of competing siderophores (1a, 2a, 3a, 3a-Fe, DFO-B) on the antibacterial activity of β-lactam sideromycins (1b, 2b, and 3b) against S. aureus SG511 in the agar diffusion assay. The vertical axis indicates the diameter of the growth inhibition zone in mm and horizontal axis represents the test compound. The assay was performed in triplicate and standard deviations are indicated by error bars. aMHII-Fe: Mueller-Hinton agar No. 2 + 100 µM 2,2’-bipyridine. bMHII+Fe: Mueller-Hinton agar No. 2 + 100 µM FeCl3. cParent siderophore refers to the iron-free siderophore (1a, 2a, and 3a) with the same compound numeral as the corresponding sideromycin (1b, 2b, and 3b, respectively). Data for all mixtures corresponds to a 1:1 molar ratio of test compounds. 50 µL of sample at the concentration indicated in parentheses under the compound numbers were added to 9 mm wells as described in the experimental section. The tabulated numerical data for this chart is provided in the Supporting Information (Tables S2 and S3).