TABLE 3.

β-galactosidase activity of trim-back deletions of the rtxBDE promoter::lacZ reporter plasmid

rtxBDE promoter length (bp)aβ-Galactosidase activity (Miller units) for indicated phaseb
LogStat
349111 ± 047.5 ± 4
349 (luxO mutant)123 ± 862.0 ± 4
180118 ± 146.1 ± 3
156151 ± 591.8 ± 6
132151 ± 347.8 ± 2
103136 ± 874.0 ± 2
72102 ± 459.7 ± 8
49153 ± 285.6 ± 6
361.5 ± 0.43.3 ± 0.7
171.5 ± 0.83.7 ± 0.3
0 (lacZ control)1.7 ± 0.63.2 ± 0.2
349 (discriminator mutant)105 ± 5102 ± 7
  • a The promoter length is the number of base pairs upstream of the rtxB transcriptional start site.

  • b N16961 strains containing trim-back deletions of the rtxBDE promoter::lacZ reporter plasmid were assayed for β-galactosidase activity during log (A 600 = 0.4) and stationary (A 600 = 3.0) growth. Values are expressed as means ± standard deviations.