Table 2. The efficiencies of first double-crossover recombination and counter-selectiona.
| Mutantb | DR (bp) | The first double-crossoverc | xylose induction concentrationd | |||
| 0% | 0.5% | 1.0% | 2.0% | |||
| ccpN* | 30 | (4.8±0.2)×103 | (2.8±0.1)×10−6 | (3.9±0.4)×10−5 | (8.4±0.1)×10−4 | (3.1±0.3)×10−4 |
| ΔccpN | 30 | (3.6±0.3)×103 | (2.7±0.4)×10−6 | (4.0±0.3)×10−5 | (7.8±0.2)×10−4 | (4.3±0.3)×10−4 |
| ileS* | 1691 | (4.2±0.2)×103 | (7.4±0.4)×10−6 | (4.3±0.2)×10−5 | (8.8±0.4)×10−4 | (4.7±0.5)×10−4 |
a
Data are means ± SD from three independent experiments for genetic manipulations.
b
ccpN*, point mutation of ccpN gene (G130T); ileS*, point mutation of ileS gene (G1399A); ΔccpN, in-frame deletion of ccpN gene.
c
The first double-crossover recombination efficiency was calculated as the number of CmR colonies/µg of dsDNA PCR product.
d
Counter-selection efficiency was calculated as Nr/Nt. Nr, number of 5FUR CmS colonies in the culture treated by different concentration of xylose; Nt, number of total colonies in culture treated by different concentration of xylose.