TABLE 3.

FecA-, FecA(ΔTonB box)-, FecA(Fhubox)-, and FecA(Fepbox)-mediated growth promotion by ferric citrate as the sole iron source

Straina	Plasmidb	TonB box sequence in FecA	Genes present	Growth zone (mm)c
				1 mM	10 mM	100 mM	1 M
AB2847				13	23	34	45
WA1031				0	0	0	(24)
	pHSG576			0	0	0	(22)
	pMMO203			0	0	0	(20)
	pLCIRA	FecA (DALTV)		13	24	34	46
	pMON45	FecA (ΔTonB box)		0	0	0	(35)
	pMON27	FhuA (DTITV)		13	23	33	49
	pMON29	FepA (DTIVV)		14	24	34	50
AB2847				11	19	28	40
AA93				0	0	0	0
	pT7-7			0	0	0	0
	pIS711		fecA(WT)d		0	0	0
	pMON37		fecBCDE	0	0	14	28
	pMON28		fecABCDE	10	19	29	44
	pMON44		fecA(ΔTonB box)	0	0	0	0
	pMON55		fecA(ΔTonB box) fecBCDE	0	0	13	29

^a Growth measurements of plasmids were determined in strain WA1031 (AB2847 fecA) or AA93 (AB2847 Δfec) as indicated.

^b The plasmids listed also carry the fecIR regulatory genes.

^c Growth was measured as the diameters of the growth zones around 6-mm-diameter filter disks that had been saturated with 10 μl of the indicated concentrations of sodium citrate. Numbers in parentheses indicate weak growth.

^d WT, wild type.