Integration and excision of plasmid DNA in Lactococcus lactis subsp. lactis.
The capacity of the 75-kb lactose-proteinase plasmid pCI301 from Lactococcus lactis subsp. lactis UC317 to recombine with the lactococcal chromosome was examined. Low-frequency integration of pCI301 sequences was detected following protoplast transformation of strain MG136Sm with total plasmid DNA from strain UC317. Excision of integrated sequences was subsequently observed at a low level. Excised sequences were rescued through recombination with and mobilization by the conjugative enterococcal plasmid pAMB1. Transconjugants harboring novel recombinant pCI301::pAMB1 plasmids, both pAMB1 and a pCI301 derivative, and pAMB1 only were isolated. The latter represents a class of transconjugant in which an elevated level of reintegration of pCI301 DNA in the recipient chromosome has occurred.
Hayes
F
F
Department of Food Microbiology, University College, Cork, Ireland.
Law
J
J
Daly
C
C
Fitzgerald
G F
GF
D002876:Chromosomes, Bacterial; D004269:DNA, Bacterial / Q000235:genetics*; D005819:Genetic Markers; D013294:Lactococcus lactis / Q000235:genetics*; D010957:Plasmids; D011995:Recombination, Genetic
D004269:DNA, Bacterial; D005819:Genetic Markers