TABLE 3.

Expression of the dnaK promoter fused to lacZ in P. putida PCL1445, PCL1622 (gacA mutant) and PCL1623 (gacS mutant)

StrainaRelative β-galactosidase activity (Miller units)
Wild type
PCL1445 (empty vector)9.68 ± 0.93
    PCL1445-pMP5536 (PdnaK lacZ mutant)b24.71 ± 2.83
    PCL1445-pMP5535 (PdnaK lacZ+)c75.43 ± 1.36
PCL1622 (gacA mutant)
    PCL1622-pMP5535 (PdnaK lacZ+)32.18 ± 1.79
    PCL1622-gacA+-pMP5535 (PdnaK lacZ+)70.80 ± 3.11
PCL1623 (gacS mutant)
    PCL1623-pMP5535 (PdnaK lacZ+)30.94 ± 2.44
    PCL1623-gacS+-pMP5535 (PdnaK lacZ+)69.55 ± 3.46
  • a pML103 (empty reporter vector) and pMP5536 containing the dnaK promoter cloned in the reverse orientation were used as control vectors. Cells were grown in KB medium to stationary phase under the normal growth condition (28°C).

  • b lacZ mutant, lacZ reporter gene in transcriptionally inactive orientation.

  • c lacZ +, lacZ reporter gene in transcriptionally active orientation.