Table 3.
Effect of carbon source on pssA-lacZ transcription in R. leguminosarum bv. trifolii 24.2 and E. coli strains
| Plasmid | CRP box genotyped | β-Galactosidase activity by strain and conditiona |
|||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 24.2 (wild type) |
VH1000 (wild type) |
VH1000 (cyaA Kmr) |
M182 (Δcrp) |
||||||||||
| +Glyb | +Glcb | Gly/Glcc | +Gly | +Glc | Gly/Glc | +Gly | +Glc | Gly/Glc | +Gly | +Glc | Gly/Glc | ||
| pPA1 | 1, 2 | 4,156 ± 342 | 2,078 ± 168 | 2.0* | 116 ± 28 | 86 ± 16 | 1.37* | 83 ± 19 | 86 ± 32 | 0.96 | 106 ± 25 | 98 ± 33 | 1.08 |
| pPA2 | 4,206 ± 332 | 4,621 ± 332 | 0.91 | 86 ± 19 | 95 ± 17 | 0.91 | 102 ± 26 | 96 ± 29 | 1.06 | 134 ± 20 | 127 ± 28 | 1.06 | |
| pPA3 | 2,982 ± 226 | 2,813 ± 208 | 1.06 | 96 ± 22 | 97 ± 23 | 0.99 | 85 ± 23 | 77 ± 24 | 1.10 | 142 ± 26 | 135 ± 24 | 1.05 | |
| pPA4 | 2,341 ± 198 | 2,273 ± 145 | 1.03 | 94 ± 16 | 89 ± 18 | 1.05 | 81 ± 28 | 75 ± 18 | 1.08 | 141 ± 18 | 136 ± 21 | 1.03 | |
a
Three cultures per strain and condition were inoculated to an OD600 of 0.08 and grown for 24 h in M1 medium supplemented with Tc and 1% glycerol (+Gly) or 1% glucose (+Glc) and assayed in triplicate.
b
Values (Miller units) are means ± standard deviations of three independent experiments.
c
Gly/Glc, activity with Gly/activity with Glc. *, statistically significant difference (P < 0.05) for the individual fusion between glycerol and glucose conditions.
d
Numbers refer to CRP boxes (Fig. 1).