TABLE 2.
Effect of dnaA(Ts) mutations on expression of a his-lac operon fusion at 28 and 37°Ca
| Strain | dnaA allele | β-Galactosidase activity in Miller units (deattenuation ratio)
|
|
|---|---|---|---|
| 28°C | 37°C | ||
| MA4527 | Wild type | 93 (1.0) | 110 (1.0) |
| MA4526 | dnaA747 | 206 (2.2) | 994 (9.0) |
| MA4522 | dnaA727 | 220 (2.4) | 863 (7.8) |
a
Bacterial cultures were grown overnight at 28°C in nutrient broth (NB), diluted 1 to 200, and incubated under aerobic conditions at 28 or 37°C in NB. Cell growth was monitored spectrophotometrically. At an optical density at 600 nm of 0.3 to 0.4, cell cultures were chilled on ice, and β-galactosidase activity was measured in toluene-permeabilized cells as described previously (22); the reported values represent the averages of at least three independent determinations. The standard error was below 10% in all cases.