TABLE 2.
Influence of a ctsR mutation on expression of the clpC operona
| Strain (genotype) | β-Galactosidase activity (Miller units)
|
Fold induction | Fold derepression of basal level | |
|---|---|---|---|---|
| Exponential growth (control) | 30-min heat shock at 50°C | |||
| BEK67 (wild type) | 7.7 | 178 | 23 | 1 |
| BEK68 (ΔsigB) | 5.1 | 128 | 25 | 1 |
| BEK86 (ΔctsR) | 59 | 188 | 3.2 | 7.7 |
| BEK87 (ΔctsR ΔsigB) | 49 | 128 | 2.6 | 9.6 |
a
Cells were grown in LB medium at 37°C to the mid-exponential phase and then exposed to heat shock at 50°C for 30 min. Samples were taken immediately before and after exposure to heat shock, and β-galactosidase activities, induction ratios, and derepression levels were determined. The results are averages of at least three experiments.