TABLE 3.
Cell density and sporulation frequencies of parent, recA, and recF strains
| Strain (relevant genotype) | Absolute no. of CFUa
|
Sporulation (%)b | Frequency relative to parent
|
|||
|---|---|---|---|---|---|---|
| No heat | Heat | Sporulation | Viable count | Heat survival | ||
| BR151 (parent) | 8.3 × 107 | 5.5 × 107 | 66 | 1.0 | 1.0 | 1.0 |
| SL7360 (recA::neo) | 8.1 × 106 | 3.6 × 106 | 45 | 0.68 | 0.097 | 0.067 |
| SL7609 (recF::spc) | 5.9 × 107 | 2.9 × 107 | 49 | 0.74 | 0.71 | 0.52 |
a
Numbers refer to the number of CFU normalized to bacterial dry weight (in milligrams) observed on LB agar. See text for details.
b
Sporulation was assessed 21 h after the cessation of exponential growth. The percentages shown here were within 2% of those obtained by phase-contrast microscopic examination just prior to plating. Heat treatment was for 20 min at 80°C.