TABLE 6.

Ability of P. shigelloides TonB and V. cholerae TonB1 and TonB2 to function in high-salt medium

E. coli 1017 transformed with plasmid:	Growth in media containinga:
	L broth		L broth with EDDA (low salt)	L broth with EDDA plus heme
	Low salt	High salt		Low salt	High salt
pHUG7/pHUG2 (P. shigelloides TonB)	1.94	1.56	0.02	1.77	1.37
pHUG7/pTEE1 (V. cholerae TonB1)	2.20	1.77	0.00	1.90	1.40
pHUG7/pCos3 (V. cholerae TonB2)	2.03	1.76	0.05	1.30	0.40

^aStrains were grown in L broth containing 170 mM NaCl (low salt) or 625 mM NaCl (high salt) containing no EDDA or containing 200 μg of EDDA per ml. with or without hemin. Absorbance at 600 nm was taken after 18 h of growth.