TABLE 3.
Effect of mtrB overexpression in strains containing a 5′ stem-loop deletion
| Strain | Relevant genotype | Plasmid | β-Gal activitya
|
β-Gal ratio (−Trp/+Trp) | |
|---|---|---|---|---|---|
| +Trp | −Trp | ||||
| PLBS254 | Wild type | pHY300PLK | 0.1 ± 0.03 | 44 ± 12 | 440 |
| PLBS253 | Wild type | pSI45 (mtrB+) | 0.1 ± 0.02 | 18 ± 5.9 | 180 |
| PLBS256 | Δ5′S-L | pHY300PLK | 23 ± 6.7 | 391 ± 73 | 17 |
| PLBS255 | Δ5′S-L | pSI45 (mtrB+) | 0.3 ± 0.08 | 143 ± 23 | 477 |
a
The β-Galactosidase (β-Gal) activity expressed from the trpE′-′lacZ fusion is given in Miller units (28). Values are averages from at least four independent experiments ± standard deviations. +Trp, in the presence of Trp; −Trp, in the absence of Trp.