TABLE 2.
Frequency of transformation of L. lactis subsp. cremoris MG1363
| attP plasmid | Frequency of transformation a
|
% of site-specific recombinationb | |
|---|---|---|---|
| pLB65 (orf1 plasmid) | pCI372 (vector) | ||
| pBF12 | 1 × 107 | 5 × 103 | 99.9 |
| pBF17 | 2 × 107 | 2 × 104 | 99.9 |
| pBF18 | 9 × 106 | 7 × 103 | 99.9 |
| pBF20 | 1 × 107 | 4 × 103 | 99.9 |
| pBF26 | 1 × 107 | 1 × 104 | 99.9 |
| pBF27 | 1 × 104 | 1 × 104 | 0.0 |
| pBF30 | 5 × 106 | 5 × 103 | 99.9 |
| pTRKH2c | 1 × 107 | 1 × 107 | 0.0 |
| None | 0 | 0 | ND |
a
Number of erythromycin-resistant transformants of L. lactis subsp. cremoris MG1363 containing pLB65 or pCI372 per microgram of attP plasmid DNA.
b
Percentage of insertions of attP plasmids due to site-specific recombination, calculated as (1 − B/A × 100, where A is the number of transformants containing pLB65 and B is the number of transformants containing pCI372. ND, not done.
c
Plasmid pTRKH2 is able to replicate in L. lactis subsp. cremoris MG1363 and was used to compare the competence of cells containing pLB65 and pCI372.