TABLE 2.
Dependence of PA-hydrolase activity in P. putida AC577 and E. coli DH5α on the presence of the phnR gene
| Strain | Plasmid (substrate)a | phnR gene | PA-hydrolase activity ± SDb
|
||
|---|---|---|---|---|---|
| No inducer | PA induction | 2PP induction | |||
| P. putida | |||||
| AC577 | pLA82 (PA) | + | 0.31 ± 0.03 | 26.5 ± 1.7 | 35.25 ± 2.2 |
| AC577 | pLA82 (2PP) | + | <0.01 | 0.65 ± 0.06 | 0.35 ± 0.05 |
| AC577 | pLA45 (PA) | − | 31 ± 1.8 | 36 ± 1.4 | 39.7 ± 1.4 |
| AC577 | pLA45 (2PP) | − | 0.28 ± 0.06 | 0.34 ± 0.04 | 0.10 ± 0.01 |
| E. coli | |||||
| DH5α | pKK6-4 (PA) | + | 0.22 ± 0.02 | 2.5 ± 0.12 | 1.90 ± 0.16 |
| DH5α | pKK2-26 (PA) | − | 0.24 ± 0.03 | 0.27 ± 0.02 | 0.25 ± 0.04 |
| DH5α | PKK38 (PA) | + | 0.14 ± 0.03 | 2.1 ± 0.15 | <0.01 |
a
Identities of the inserts containing the phnA gene region are shown in Fig. 1.
b
Specific activity of PA hydrolase given as Pi release ± SD in nanomoles per minute per milligram. For this analysis, cultures of P. putida and E. coli were grown and prepared as described in Materials and Methods. Cell-free extracts were then prepared, and PA-hydrolase activity was assayed. The results are expressed as an average of three experiments.