Table 2.

Effect of the arlS deletion and truncatednorA promoters on norA expression

PlasmidStrain
ISP794BF15
β-Lactamase activityaRatiobβ-Lactamase activityaRatiob
pWN2018≤2,000≤2,000
pBF8-309,400 ± 3301.024,300 ± 1801.0
pBF8-30 plus pBF16-49,200 ± 1461.016,700 ± 14300.7
pBF3-5011,700 ± 3901.225,500 ± 8501.0
pBF4-39,510 ± 5101.07,770 ± 4200.3
pBF15-59,230 ± 8101.010,700 ± 15400.4
  • a Results are expressed in units of β-lactamase per gram of proteins. All determinations were performed in triplicate.

  • b Ratios of β-lactamase activities with respect to that of the wild-type promoter in both strains.