TABLE 2.
Repression of the maltose regulon when glp genes are amplified
| Fusion and introduced plasmida | β-Galactosidase activityb
|
Repression by glpc
|
||
|---|---|---|---|---|
| pHo 5 | pHo 7 | pHo 5 | pHo 7 | |
| Φ(malK′-lacZ+)1 (pGPH1768) | ||||
| pACYC177 | 189 ± 11 | 339 ± 51 | ||
| pGPH9925 (glpFKX) | VL | VL | Full | Full |
| pGPH11250 (glpFK) | VL | VL | Full | Full |
| pGPH9993 (glpF) | 136 ± 18 | 328 ± 29 | 1.4 | 1 |
| pGPH11264 (glpK) | VL | 90 ± 32 | Full | 3.8 |
| pGPH11249 (glpX) | 153 ± 40 | 295 ± 74 | 1.2 | 1.1 |
| Φ(malT′-lacZ+)1 (pGPH8881) | ||||
| pACYC177 | 417 ± 86 | 593 ± 41 | ||
| pGPH9925 (glpFKX) | 162 ± 35 | 194 ± 25 | 2.6 | 3.1 |
| pGPH11250 (glpFK) | 150 ± 21 | 244 ± 58 | 2.8 | 2.4 |
| pGPH9993 (glpF) | 328 ± 7 | 657 ± 53 | 1.3 | 1.1 |
| pGPH11264 (glpK) | 128 ± 37 | 232 ± 34 | 3.3 | 2.6 |
| pGPH11249 (glpX) | 395 ± 58 | 656 ± 93 | 1.1 | 0.9 |
| Φ(malP′-lacZ+)1 (pGPH9463) | ||||
| pACYC177 | 1,261 ± 21 | 2,321 ± 163 | ||
| pGPH9925 (glpFKX) | ND | 1,116 ± 26 | 2.1 | |
a
Fusions were in an MC4100 background in pJEL250.
b
β-Galactosidase activity was assayed during growth at 30°C in MM adjusted to pH 5 or 7 and supplemented with glycerol [and maltose for Φ(malP′-lacZ+)1], ampicillin, and kanamycin. ND, not done; VL, very low β-galactosidase activity (below the sensitivity threshold of the method used).
c
Repression values correspond to the ratio between β-galactosidase activities of the strain with pACYC177 and the strain with amplified glp genes.