Fig 3.

Expression of ChtA, ChtB, ChtC, and CirA is repressed by iron in the C. diphtheriae wild-type strain 1737. Bacteria were grown in high- or low-iron HIBTW medium. Proteins from either whole cells (ChtC and CirA) or supernatant fractions (ChtA and ChtB were located predominately in the supernatant in HIBTW medium) were detected by Western blotting using polyclonal antiserum specific to the proteins indicated. Samples were loaded using equivalent protein levels. +Fe, high-iron medium; −Fe, iron-depleted medium.