FIG. 1.

Use of iron from transferrin (Tf) and lactoferrin (Lf). Growth responses of Ybt⁺ KIM6+ (A and C), Ybt⁻ KIM6-2046.1 (irp2::kan2046.1) (B), and KIM6-2046.3 (Δirp2-2046.3) (D) on PMH-EDDA plates to partially saturated Tf (1, 2, 5, and 6 in panels A and B), partially saturated bovine Lf (1, 2, 5, and 6 in panels C and D), or inorganic iron (3, 4, 7, and 8) are shown. The solutions were added to wells (A and B) or on filter discs (C and D) on seeded plates (1, 3, 5, and 7) or spotted onto a dialysis membrane overlaying the bacterial cells (2, 4, 6, and 8). After incubation with Tf or Lf at 37°C, plates were overlaid with TBA containing esculin and ferric citrate to visualize bacterial growth. The images are from one of two or more independent experiments that yielded similar results.