TABLE 2.

Expression of a transcriptional p(−108, +126)yrrT′-lacZ fusion in the presence of methionine or cystine in various B. subtilis strains^a

Strain	Genotype	β-Galactosidase activity (nmol of ONP min−1 mg of protein−1)
		Methionine (1 mM)	Cystine (0.25 mM)
BSIP 1144	p(−108, +126) yrrT′-lacZ	450	55
BSIP 1314	p(−108, +126) yrrT′-lacZ cysK::spc	580	410
BSIP 1837	p(−108, +126) yrrT′-lacZ cysE14	3	6
BSIP 1840	p(−108, +126) yrrT′-lacZ cysK::spc cysE14	310	430
BSIP 1794	p(−108, +126) yrrT′-lacZ cymR::aphA3	490	480

^aCells were grown in minimal medium containing 1 mM methionine and 0.25 mM cystine until they reached an OD₆₀₀ of 2. They were then centrifuged, washed three times in minimal medium without any added sulfur source, and resuspended in minimal medium containing either 1 mM methionine or 0.25 mM cystine. Cells were harvested 2 h after resuspension.