TABLE 3.
β-Galactosidase activities in cell extracts of R. sphaeroides bearing the hemF::lacZ transcriptional fusion plasmid pJZ84
| Strain | β-Galactosidase activitya
|
|||
|---|---|---|---|---|
| 30% oxygen
|
Anaerobic
|
|||
 |
σn |  |
σn | |
| Wild type 2.4.1(pJZ84) | 908 | 27 | 296 | 7 |
| PRRA2(pJZ84) | 510 | 11 | 795 | 13 |
Activities are expressed in units of β-galactosidase activity, defined as micromoles of o-nitrophenyl-β-d-galactopyranoside hydrolyzed per minute per milligram of protein extract. Values with means (
) and standard deviations (σn) indicated are from duplicate assays of activities in extracts from three independent isolates. The strains were grown in Sistrom's minimal succinate (24) with tetracycline (final concentration, 0.8 μg ml−1) either aerobically; by sparging liquid cultures with a mixture of 30% oxygen, 5% carbon dioxide, and 65% nitrogen; or anaerobically in the dark with dimethyl sulfoxide as alternate electron acceptor.