TABLE 1.

BACTH analysis of Crl-σ interactions The table lists measured β-galactosidase activities in BTH101 cya cells carrying pKT25 derivatives encoding a T25-σ⁷⁰ or a T25-σ^s fusion protein and pUT18 derivatives encoding Crl-T18 and Rsd-T18 fusions. Cells were grown on MacConkey maltose plates containing 100 μg/ml ampicillin, 50 μg/ml kanamycin, and 0.5 mm isopropyl 1-thio-β-d-galactopyranoside at 30°C before measuring β-galactosidase activities. No difference in activity was detected between E. coli Crl-T18 and S. enterica Crl-T18.

	Protein fusion 1	Protein fusion 2	β-Galactosidase activity
			Miller units
1	T25-σ70	T18	63
2	T25-σ70	E. coli Crl-T18	60
3	T25-σ70	S. enterica Crl-T18	62
4	T25-σ70	E. coli Rsd-T18	1022
5	T25-σs	T18	60
6	T25-σs	E. coli Crl-T18	696
7	T25-σs	S. enterica Crl-T18	698
8	T25-σs	E. coli Rsd-T18	72