TABLE 5.

Effects of 2,2"-dipyridyl on Rob-mediated activation of inaA::lacZ when Rob is expressed from the heterologous lac promoter^a

Strain	Activator controlled by the lac promoter	β-Galactosidase activity (Miller units) with 2,2"-dipyridyl at:		Ratiob
		0 mM	5 mM
M597	None	10	16	1.6
M598	MarA	45	23	0.51
M599	SoxS	30	32	1.1
M600	Rob	33	587	18.0

^aThe mar sox rob mutant strains carrying the indicated plasmids were grown to early log phase, treated with 0 or 5 mM 2,2"-dipyridyl for 1 h at 37°C, and assayed for β-galactosidase activity.

^bThat is, the ratio of activities in the cells treated with 2,2"-dipyridyl to that in the untreated cells.