TABLE 6.
Generation times of wild-type E. coli and mutants with disruptions of astB and astC
| Nitrogen sourcea | Generation time, min ± SEM (n)b, for:
|
||
|---|---|---|---|
| W3110 | astB | astC | |
| NH3 | 77.8 ± 3.6 (6) | 83.0 ± 1.7 (3) | 71.3 ± 0.5 (3) |
| Glutamine | 120 ± 7.0 (6) | 129 ± 2.9 (3) | 105 ± 1.2 (3) |
| Alanine | 120 ± 2.1 (6) | 126 ± 4.1 (3) | 106 ± 3.5 (3) |
| Proline | 265 ± 7.6 (3) | 288 ± 4.9 (3) | 310 ± 1.7 (3) |
| Aspartate | 329 ± 13 (6) | 331 ± 13 (2) | 326 ± 3.6 (3) |
| Ornithine | 301 ± 7.1 (9) | 303 ± 6.5 (6) | 655 ± 24 (6) |
| Aspartate-ornithinec | 237 ± 12 (6) | 249 ± 15 (6) | 236 ± 11 (3) |
| Arginine | 540 ± 32 (9) | NDd | ND |
| Arginine-aspartatec | 105 ± 0.8 (3) | ND | ND |
| Aspartate-argininec | 105 ± 5.0 (6) | 178 ± 4.8 (3) | 271 ± 26 (3) |
a
Cells were grown in minimal medium with 0.4% glucose and 0.2% of the indicated nitrogen source.
b
The generation times are expressed as minutes ± standard error of the mean, with the number of determinations given in parentheses.
c
The first nitrogen source was at 0.2%; the second nitrogen source was at 0.01%.
d
ND, no detectable growth after 1 week.