TABLE 1.
Bacterial strains used in this study
| S. typhimurium strain | Genotypea | Source or reference |
|---|---|---|
| LT2 derivatives | ||
| TT16813 | recD542::Tn10dCam | 19 |
| MST3063 | leuA414(Am) hsdL (r− m+) FelS−mutS121::Tn10 | 29 |
| ATCC 14028s derivatives | ||
| MST3083 | Wild type | ATCCb |
| MST4172 | mutS121::Tn10 | This study |
| MST4174 | recD542::Tn10dCam | This study |
| MST4175 | mutS121::Tn10 recD542::Tn10dCam | This study |
| JS110 | recA1 | 16 |
All of the strains used were derivatives of S. typhimurium LT2 or S. typhimurium ATCC 14028s. mutS, recD, or mutS recD derivatives of S. typhimurium 14028s were constructed by P22-mediated transduction of DNA from S. typhimurium LT2 (29). Tn10dCam refers to the transposition-defective derivative of Tn10, Tn10Δ16Δ17 (5). Bacterial strains were routinely grown in rich medium (nutrient broth) composed of 0.8% Difco nutrient broth and 0.5% NaCl, or minimal medium composed of E salts (28) and 0.2% glucose. For solid medium, 1.5% Difco Bacto-agar was added. TBSA top agar contained 1% tryptone, 0.5% NaCl, and 0.7% agar. Tetracycline and chloramphenicol were each added at 20 μg/ml. Bacteria were diluted in 0.85% NaCl unless otherwise indicated.
ATCC, American Type Culture Collection, Manassas, Va.