Iron limiting conditions induce biosynthesis and secretion of siderophores.

<p>A: Detection of siderophores in MMcM agar plates. Under iron sufficiency (30 µM Fe), the production of these chelators was repressed in solid medium. B: Percent siderophore activity was determined in <i>Pb</i>01and <i>Pb</i>18 supernatants. Values are expressed as mean <u>+</u> standard deviation of three experiments. *statistically significant difference determined by Student's <i>t</i>-test (p<0.05).