TABLE 3.

β-Galactosidase fusion analysis of various dct promoters

Strain	Genotype	Fusiona	β-Galactosidase activity under the following growth conditionb:
			Glc-NH4	Succ-NH4	Glc-Asp	Succ-Asp
3841	Wild type	dctB-lacZ	778 ± 90	1,211 ± 40	1,318 ± 403	743 ± 116
RU150	dctA101	dctB-lacZ	596 ± 48		630 ± 48	470 ± 47
3841	Wild type	dctD1-lacZ	172 ± 5	214 ± 8	192 ± 14	174 ± 9
3841	Wild type	dctD2-lacZ	166 ± 40	228 ± 34	265 ± 79	230 ± 77
3841	Wild type	dctBD-lacZ	788 ± 18	1,454 ± 56	1,180 ± 88	749 ± 50
RU150	dctA101	dctBD-lacZ	701 ± 35		777 ± 43	741 ± 13
3841	Wild type	dctA101-lacZ	406 ± 60	450 ± 52	406 ± 69	649 ± 117
RU150	dctA101	dctA101-lacZ	347 ± 30		348 ± 25	350 ± 34
RU730	dctB::Ω	dctA101-lacZ	405 ± 26		362 ± 52
RU711	dctD::Ω	dctA101-lacZ	379 ± 32		442 ± 37
3841	Wild type	dctA101B-lacZ	1,054 ± 66	1,531 ± 40	1,149 ± 119	1,137 ± 127
RU150	dctA101	dctA101B-lacZ	1,025 ± 45		1,173 ± 91	896 ± 90
3841	Wild type	dctA101BD-lacZ	975 ± 58	1,459 ± 66	1,179 ± 58	1,123 ± 16
RU150	dctA101	dctA101BD-lacZ	906 ± 75		1,198 ± 25	1,037 ± 76
3841	Wild type	pMP220	120 ± 40	168 ± 21	180 ± 42	205 ± 62
RU150	dctA101	pMP220	142 ± 22		153 ± 33	245 ± 5

^aThe dct-lacZ fusions are as follows: dctB, pRU104; dctD₁, pRU292; dctD₂, pRU392; dctBD, pRU354; dctA101, pRU105; dctA101B, pRU106; dctA101BD, pRU352. pMP220 is the vector alone. 

^bResults are shown as o-nitrophenylgalactoside hydrolyzed (in nanomoles per minute per milligram of protein ± SEM) and are based on at least three independent cultures assayed in triplicate. Glc, glucose; Succ, succinate; Asp, aspartate. All growth substrates were at 10 mM concentrations.