TABLE 2.
Identification of a TP901-1 promoter and a regulator of the promotera
| Strain | Plasmids | Promoter fusion to lacLM | Relevant genotype of PnisA plasmid | Sp act of β-galactosidase (U/ml × OD600)
|
|
|---|---|---|---|---|---|
| Without nisin | With nisin | ||||
| LB560 | pMBP14 and pMBP22 | Plate | orf29-gusA | 2.0 | 67 |
| LB562 | pMBP14 and pNZ8010 | Plate | gusA | 0.05 | 0.09 |
| LB568 | pAK80 and pMBP22 | None | orf29-gusA | 0.02 | 0.06 |
| LB570 | PAK80 and pNZ8010 | None | gusA | 0.04 | 0.06 |
a
Overnight cultures of each strain were diluted in two tubes containing fresh medium (GM17 medium containing 5 μg of erythromycin per ml and 5 μg of chloramphenicol per ml) to an OD600 of 0.01. After growth for two to three generations, nisin was added to one set of the cultures to a final concentration of 1 ng/ml. After approximately six generations of growth (overnight incubation), OD600 (as well as the activities of β-galactosidase and β-glucuronidase) was determined. One representative of two experiments is shown.