TABLE 4.

rpoS-dependent transcriptional activity of E. coli sodC promoter^a

E. coli strain	β-Gal activity (U) at:
	3 h	24 h	48 h
GC4468(pMC1403)	0.40 ± 0.27	0.2 ± 0.17	0.1 ± 0.2
GC4468(pMCPromEcSOD)	58.75 ± 18.50	258.7 ± 63.3	420 ± 32.6
QC1110(pMC1403)	0.1 ± 0.05	0.11 ± 0.1	0.14 ± 0.03
QC1110(pMCPromEcSOD)	3.05 ± 0.4	31.5 ± 7.54	39.4 ± 1.8

^aOvernight E. coli cultures were diluted 1:100 in LB medium and grown up to 2 days at 37°C. Samples were withdrawn at different times, and activity values were standardized to cell concentrations. Cells collected at 3 h after subculturing were still in mid-log phase. The values reported here are the means ± standard deviations of four different experiments.