. 1998 Dec;180(24):6719–6728. doi: 10.1128/jb.180.24.6719-6728.1998

TABLE 3.

LacZ expression from plasmids carrying btuB-lacZ fusions expressed from heterologous promoters

Host strain	Promoter	Presence of 0.5 mM IPTG	β-Galactosidase activity (U) with transcriptional fusion		RR^a	β-Galactosidase activity (U) with translational fusion		RR^a
Host strain	Promoter	Presence of 0.5 mM IPTG	−Ado-Cbl	+Ado-Cbl	RR^a	−Ado-Cbl	+Ado-Cbl	RR^a
RK5173	btuB	−	3,035	535	5.7	435	14	31
RK5173	blaP	−	2,925	625	4.7	640	36	17.8
JM109	lacP	−	5,380	1,695	3.2	1,085	25	43
JM109	lacP	+	7,250	2,200	3.3	2,775	60	46
RK5173	T7	−	70	78	1.0	10	2	5
RK3513	T7	−	450	365	1.2	45	12	3.8
RK3513	T7	+	5,015	4,790	1.1	975	470	2.6

RR, repression ratio (activity −Ado-Cbl/activity +Ado-Cbl).