TABLE 5.
Growth of revertants in mixed culturesa
| Strain and revertantsb | Avg no. of colonies from 3 plates
|
||
|---|---|---|---|
| His+ | Met+ | Leu+ | |
| YB955 | |||
| A | 36.7 | 41.0 | 41.3 |
| B | 40.3 | 34.7 | 46.7 |
| C | 29.0 | 42.0 | 45.0 |
| BG | 1.0 | 1.3 | 0.3 |
| YB9000 (comA) | |||
| A | 25.3 | 55.7 | 28.0 |
| B | 24.0 | 23.7 | 28.3 |
| C | 38.3 | 25.7 | 27.0 |
| BG | 1.7 | 0.7 | 0.3 |
| YB9100 (comK) | |||
| A | 44.7 | 41.3 | 25.3 |
| B | 32.3 | 23.3 | 24.3 |
| C | 38.7 | 26.3 | 24.3 |
| BG | 0.7 | 1.0 | 0.7 |
| YB9200 (comA comK) | |||
| A | 31.7 | 27.0 | 29.3 |
| B | 25.0 | 27.0 | 23.0 |
| C | 29.7 | 30.3 | 32.3 |
| BG | 1.0 | 0.7 | 0.7 |
a
His+, Met+, and Leu+ revertants that arose on day 6 from each strain were mixed with about 5 × 108 CFU of bacteria representing the strain from which they had originally been isolated, plated on minimal medium, and incubated at 37°C. All colonies were scored and recorded within 48 h.
b
Nine stationary-phase mutagenesis-generated revertants were isolated from each strain. A, B, and C each represent one set of three isolates; each set includes one His+, one Met+, and one Leu+ strain. BG is the number of background revertants that appeared on the medium after 48 h of incubation at 37°C (number of revertants generated during growth-dependent mutagenesis).