TABLE 2.
σB activity in mutant rsbR and rsbS strains during growth and physical stress
| Strain | β-Galactosidase (ctc::lacZ) activity (Miller units) under the indicated conditionsa
|
|||
|---|---|---|---|---|
| Merodiploidb | Single copyc
|
4% ethanold | ||
| Growth (OD, 0.5) | Stationary phase | |||
| Wild type (RsbP−) | 1.2 ± 0.3 | 1.0 ± 0.1 | 0.6 ± 0.7 | 37.7 ± 0.1 |
| rsbR(136EK) | 19.2 ± 0.6 | 21.4 ± 0.9 | 34.5 ± 2.6 | 98.4 ± 4.6 |
| rsbR(225CY) | 28.5 ± 2.2 | 42.3 ± 1.8 | 62.4 ± 4.0 | 97.6 ± 2.2 |
| rsbS(22ER) | 42.5 ± 7.2 | 60.7 ± 0.1 | 82.5 ± 3.7 | 119.0 ± 6.9 |
| rsbS(23LF) | 3.6 ± 0.9 | 1.2 ± 0.1 | 6.9 ± 1.3 | 52.8 ± 0.7 |
| rsbS(66GR) | 6.6 ± 1.0 | 13.2 ± 1.1 | 39.9 ± 3.3 | 117.0 ± 9.3 |
| rsbS(76GR) | 3.1 ± 1.1 | 5.3 ± 0.6 | 4.4 ± 0.3 | 75.7 ± 3.7 |
| rsbS(83GD) | 3.1 ± 0.4 | 1.4 ± 0.1 | 10.6 ± 2.4 | 69.5 ± 2.1 |
| rsbS(86PL) | 7.3 ± 2.9 | 11.6 ± 1.6 | 36.4 ± 2.2 | 77.1 ± 8.9 |
a
Values are averages of three separate determinations ± standard deviations.
b
Merodiploid strains contain two copies of the PA rsbR rsbS rsbT rsbU element. Both copies are wild type in the first strain listed. The remaining strains contain the indicated allele of rsbR or rsbS in one of the two elements, with its wild-type counterpart in the other. All strains are RsbP−.
c
Strains are RsbP− and contain single copies of sigB operon genes with the indicated alleles. Stationary-phase values were obtained 30 min after the cessation of growth.
d
Samples were taken from actively growing cultures at 20 min after ethanol addition.