TABLE 5.

Activation of a VC0770 promoter-lacZ fusion by low pH

Strain	β-Galactosidase activitya		Fold change
	LB medium, pH 7.0b	LB medium, pH 5.5c
WL344 (ΔVC0770-lacZ)	2,591 ± 65	4,403 ± 42	1.7
WL346 (ΔaphB)	79 ± 1	51 ± 1	0.64

	M9 medium, pH 7.0	M9 medium, pH 6.0
WL344 (ΔVC0770-lacZ)	210 ± 12	1,149 ± 32	5.5
WL346 (ΔaphB)	45 ± 2	41 ± 5	0.91

^aUnits per OD₆₀₀ of culture.

^bBuffered with 100 mM Trizma.

^cBuffered with 100 mM MES.