Figure 2.

GaPPIX inhibits P. aeruginosa PAO1 growth under iron-deplete conditions. (A) P. aeruginosa PAO1 was grown for 24 h at 37°C in DCAA in the presence of different concentrations of Hemin (black bars), Ga(NO₃)₃ (dark gray bars), GaPPIX (light gray bars), or nothing (white bar). Control cultures were supplemented with 100 μM FeCl₃ and 100 μM of either Ga(NO₃)₃ or GaPPIX. Values are the mean of 3 independent experiments, each one performed in duplicate ± the standard deviation. (B) Approximately 5 × 10⁶ P. aeruginosa PAO1 cells were seeded on the surface of DCAA agar plates, supplemented or not with 600 μM FeCl₃, as indicated on top. Then, disks soaked with 10 μl of a 15 mM solution of either GaPPIX or Ga(NO₃)₃ were deposited on the agar surface, as indicated on the left. Plates were incubated for 16 h at 37°C. Images are representative of three independent experiments yielding similar results.