Figure 4.

Heme protects Pseudomonas aeruginosa from CP-mediated iron-starvation responses.A, fluorescence intensity detected by HPLC (λ_ex = 398 nm, λ_em = 455 nm) for pyoverdine (Pvd) standard and supernatants from PA14 grown in CDM in the absence or presence of CP-Ser (10 μM) and heme (5 μM). Pvd standard was purified as described previously (22). B, PAO1 antR translation was measured using an antR-lacZ translational fusion (Pseudomonas aeruginosa PAO1/P_antR-‘lacZ^-SD) following growth in Tris:TSB in the absence or presence of CP (10 μM) and heme (5 μM). β-Galactosidase activity was assayed in cell suspensions (N = 3, ∗∗p < 0.01). CDM, chemically defined medium; CP, calprotectin.