Table 3.
Influence of cognate transporters on the expression of citC-lacZ and dcuB-lacZa
| Effector | Activity (MU) |
|||||
|---|---|---|---|---|---|---|
|
citC-lacZ |
dcuB-lacZ |
|||||
| IMW548 (wild type) | IMW552 (ΔCitT−) | IMW587 (ΔDcuC−) | IMW551 (ΔDcuB−) | IMW237 (wild type) | IMW370 (ΔDcuB−) | |
| H2O | 5 ± 4 | 2 ± 1 | 0 ± 0 | 10 ± 1 | 22 ± 4 | 812 ± 32 |
| Citrate | 320 ± 20 | 364 ± 15 | 390 ± 37 | 339 ± 8 | ND | ND |
| Fumarate | 3 ± 1 | 3 ± 1 | ND | 3 ± 0 | 1,096 ± 67 | 802 ± 1 |
a
The expression of citC-lacZ or dcuB-lacZ was tested in strains with the citT, dcuC, or dcuB gene deleted in the absence and presence of an effector (citrate or fumarate). E. coli strains were grown anaerobically in eM9 medium containing glycerol (50 mM) and dimethyl sulfoxide (20 mM) with and without sodium fumarate (20 mM) or sodium citrate (20 mM), as indicated. Activities in Miller units (MU) are shown as the averages from at least four independent measurements. Standard deviations for the activities are shown. ND, not determined.