TABLE 3.

Utilization of hemin or hemoglobin as an iron source by E. coli and V. anguillarum heme uptake-deficient mutants complemented with outer membrane heme receptors huvA and huvS genes

Strain	Gene(s) present in plasmids	Utilization ofa:
		Hm at 10 μM	Hb at 1 μM	FeSO4 at 10 μM
E. coli
101ESD	None	−	−	+
101ESD/pCAR121	huvA	−	−	+
101ESD/pSML33	tonB-exbBD-huvBCD	−	−	+
101ESD/pSML33/pCAR121	tonB-exbBD-huvBCD huvA	+	+	+
101ESD/pSML92	huvS	−	−	+
101ESD/pSML33/pSML92	tonB-exbBD-huvBCD huvS	+	+	+
V. anguillarumb
H775-3	None	+ (1.27)	+ (1.31)	+ (1.20)
H775-3 ΔhuvA	None	− (0.18)	− (0.18)	+ (1.20)
H775-3 ΔhuvA/pCAR121	huvA	+ (1.17)	+ (1.10)	+ (1.18)
H775-3 ΔhuvA/pSML93	huvS	+ (1.15)	+ (1.06)	+ (1.19)

^a+ or −, growth or no growth in the plate assays. Hm, hemin; Hb, hemoglobin.

^bNumbers in parentheses indicate the OD₆₀₀ mean values in the liquid medium assays (see Materials and Methods) reached after 24 h of incubation.