Production of catechol siderophores in <i>Δasb</i> and <i>ΔentA</i> mutants.

<p>Culture supernatants were collected for each strain from overnight (20 h) cultures in low iron conditions. Measurement of catechol productions was achieved using the Arnow assay. Data were normalized to the OD₆₀₀ of cultures and percentages of wild-type (WT) catechol level are shown. Error bars represent SEM from mean values of three independent experiments. * Significant difference compared to wild type (<i>P</i><0.001). ** Significant difference compared to <i>ΔentA</i> strain (<i>P</i><0.05).