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FAQ 6: What happens if I induce for longer or shorter times?

Answer 6: Our standard induction is 15 minutes.  However, we know that shorter and longer times can work depending on the details of the experiment.  Below it can be seen that with oligo recombination, 5 minutes induction is sufficient for optimal recombination levels.  However with dsDNA recombination, a 10 minute or longer induction time is required. Likewise, long inductions with the Beta-only strain, SIMD50, are ok. This table does not include the data but long induction times of HME6 (and most recombineering strains) results in cell killing if the induction is 60 minutes or longer due to the lambda kil gene.

Gal+ /108 viable 1 Gal+ /108 viable 1 CatR /108 viable 2
0 3.1x104 1.7x104 2.0x101
1 9.0x104 1.2x104
3 7.5x106 1.2x106 1.4x102
5 2.0x107 1.5x107 2.1x104
10 3.2x107 3.1x107 1.2x105
15 1.6x107 2.8x107 1.3x105
20 1.2x107 2.6x107 6.4x104
30 1.2x107 1.6x107 1.1x104
60 1.1x107
overnight (saturated) <2x101
Overnight then dilute at 42° 6.2x106

1 Recombination with an oligo to correct the galKam to Gal+.

2 Recombination with a chloramphenicol cassette to knock-out galK