TABLE 5.
Electroporation of a linear DNA fragment (lacZ::tet)a into cells containing the ΔrecBCD::Plac-bet exo substitution
| Strain (relevant genotype) | Titer of recombinantsb (105) | Titer of survivorsb (109) | Recombinants/survivor (10−5) |
|---|---|---|---|
| AB1157 (wild type) | 0 | 1.5 | 0 |
| KM19 (ΔrecBCD sbcBC) | 0.13 | 1.7 | 0.76 |
| KM20 (ΔrecBCD::Plac bet exo sbcBC) | 4.2 | 1.8 | 23.3 |
| KM21 (ΔrecBCD) | 0 | 0.35 | 0 |
| KM22 (ΔrecBCD::Plac bet exo)c | 7.0 ± 2.1 | 2.6 ± 1.0 | 27.0 |
| KM26 (ΔrecBCD::Plac bet exo, recF) | 0.03 | 0.19 | 1.6 |
| KM29 (ΔrecBCD::Plac bet exo, recJ) | 1.9 | 0.13 | 146.1 |
| KM353 (recD) | 0.21 | 2.9 | 0.72 |
| JC9387 (recBC sbcBC)c | 0.082 ± 0.027 | 1.9 ± 1.1 | 0.43 |
a
Purified linear lacZ::tet DNA fragment (0.9 μg), generated by digestion of pKM133 with PvuII, was mixed with 50 μl of electrocompetent cells and electroporated as described in Materials and Methods.
b
Titers of electroporation mixture (60 μl); recombinants were scored as tetracyclin-resistant white colonies.
c
Trials with KM22 and JC9387 were done four times; standard deviations for titers are included. Electroporation of other strains was performed only once in this experiment.