MOBILIZATION AND EXPRESSION OF BACTERIOCIN PLASMIDS FROM CARNOBACTERIUM-PISCICOLA ISOLATED FROM MEAT

Mobilization and expression of bacteriocin plasmids from Carnobacterium piscicola isolated from meat. The nonconjugative plasmids pCP40 and pCP49 associated with bacteriocin production in Carnobacterium piscicola LV17, a lactic acid bacterium isolated from meat, were mobilized by the wide host range conjugative plasmid pAM-beta-1 by two stage conjugation. At the first stage, pAM-beta-1 was conjugally transferred into C. piscicola LV17 containing the two plasmids associated with bacteriocin production and a cryptic plasmid. Mobilization of the two bacteriocin plasmids by pAM-beta-1 was done by the second stage conjugation between the pAM-beta-1-containing C. piscicola LV17 and chloramphenicol (Cm)-resistant Bac- mutant of C. piscicola LV17. The transconjugants had either partial bacteriocin activity associated with acquisition of pCP40 or pCP49, or complete bacteriocin activity associated with acquisition of all three of the resident plasmids from C. piscicola LV17 or an 89 MDa cointegrated plasmid derived from pCP40 and pCP49. Further manipulation of the transconjugants and a mutant strain of C. piscicola LV17 resulted in separate strains with only pCP40 or pCP49 which produce different bacteriocins. The bacteriocin gene from pCP49 was cloned into pCaT, a chloramphenicol resistance-encoding vector, and electrotransformed into another bacteriocin-producing strain of C. piscicola, enhancing the antagonistic spectrum of the recipient strain.