TABLE 2.

Transcriptional activity of vie genes

Strain	Genotype	Predicted phenotype	In vitroa β-gal activity	% Tcs CFUb
				In vitroc	In vivod
AC-V311	vieS::tnpR-lacZY	VieS+A+B+	++	>80	NDe
AC-V336	vieS::tnpR-lacZY ΔvieAB	VieS+A−B−	++	>80	ND
AC-V354	vieSA::tnpR-lacZY	VieS+A+B+	+	∼50	ND
AC-V296	vieA::tnpR-lacZY	VieS+A−B−	±	0	0
AC-V232	vieB::tnpR-lacZY	VieS+A+B−	±	0	90

^aThe β-galactosidase activity of colonies was observed visually on LB agar supplemented with 50 μg of X-Gal per ml; ± represents background levels, and ++ represents transcriptional activity. 

^b% Tc^s CFU was determined by replica plating colonies onto LB agar supplemented with 2 μg of tetracycline per ml and is a measure of the transcriptional activity of the corresponding fusion to tnpR-lacZY. 

^cCultures were grown in LB broth. 

^dBacteria recovered from intestinal infection of 5-day-old CD-1 mice. 

^eND, not determined.