TABLE 2.
Stability of alr-carrying plasmids pGIP012 and pGIP013 in L. plantarum MD007Int6 and L. lactis PH3960a
| No. of generations of growth with d-ala | % of colonies with plasmids
|
|
|---|---|---|
| MD007Int6 Alr + | PH3960 Alr + | |
| 50 | 100 | 100 |
| 100 | 34 | 100 |
| 150 | 2 | 100 |
| 200 | 2 | 100 |
a
Cells were pregrown with or without d-Ala for multiples of 50 generations, and the presence of the plasmids was judged by the ability of the cells to grow without d-Ala. After culturing under selection pressure (without d-Ala), both L. plantarum and L. lactis have stably maintained their plasmids in all tested colonies. The results for the cultures grown without selection pressure (with D-ala) are presented in the table.