TABLE 2.

Phenotypic characterization of S. dysenteriae iron transport system mutants

Strain	Genotype or phenotype	Synthesis of enterobactinab	Utilization ofa:
			Hemin	Enterobactinc	Ferrichrome
SDU378	Wild type	+	+	+	+
SDU380	tonB	+	−	−	−
SDU380/pYUK1	TonB+	+	+	+	+
SDU400	shuA	+	−	+	+
SDU400/pHTL116	ShuA+	+	+	+	+
SDU402	shuA entB	−	−	+	+
SDU402/pHTL116	ShuA+entB	−	+	+	+
SDU402/pHEB1	ShuA+ EntB+	+	+	+	+

^aBioassays were performed as described in Materials and Methods. +, zone of stimulation ≥5 mm. Growth of all strains was stimulated by 20 μl of 10 mM FeSO₄. 

^bEnterobactin synthesis was determined by the ability to cross-feed the E. coli entB mutant, AB1515.24. 

^cAB1515 (5 μl of an overnight culture) was used as the enterobactin-producing strain.