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Conjugal mobilization of streptococcal plasmid pMV158 between strains of Lactococcus lactis subsp. lactis
D van der Lelie1, H A Wösten, S Bron
1Department of Genetics, University of Groningen, Haren, The Netherlands.
Abstract:
pMV158, a non-self-transmissible plasmid encoding tetracycline resistance, was conjugally transferred from Enterococcus faecalis JH203 to Lactococcus lactis subsp. lactis IL1403. This transfer appeared to be dependent on the cotransfer of the conjugative plasmids pAM beta 1 or pIP501. Intraspecies conjugal transfer of pMV158 also occurred in strain IL1403. In contrast to the transfer from E. faecalis, transfer in IL1403 did not require the presence of a conjugative plasmid in the donor strain but, rather, appeared to be dependent on putative chromosomal functions in strain IL1403. The transfer of pMV158 from strain IL1403 required the presence of an active pMV158-encoded protein, which showed homology to the Pre (plasmid recombination enzyme) proteins encoded by several small plasmids extracted from Staphylococcus aureus, such as pT181.
Insights
The non-self-transmissible plasmid pMV158 was transferred between Enterococcus faecalis and Lactococcus lactis. Transfer in Lactococcus lactis depended on chromosomal functions and a pMV158-encoded protein, unlike transfer from Enterococcus faecalis.
Area of Science:
- Bacteriology
- Molecular Biology
- Genetics
Background:
- Non-self-transmissible plasmids require assistance for transfer.
- Plasmid transfer mechanisms vary between bacterial species.
Purpose of the Study:
- To investigate the conjugal transfer of plasmid pMV158 between Enterococcus faecalis and Lactococcus lactis.
- To elucidate the requirements for pMV158 transfer in different bacterial hosts.
Main Methods:
- Conjugal transfer experiments were performed.
- Plasmid DNA was analyzed.
- Bacterial strains used included Enterococcus faecalis JH203 and Lactococcus lactis subsp. lactis IL1403.
Main Results:
- Plasmid pMV158 was successfully transferred from E. faecalis to L. lactis, requiring cotransfer of conjugative plasmids (pAM beta 1 or pIP501).
- Intraspecies transfer of pMV158 within L. lactis occurred, dependent on chromosomal functions and a pMV158-encoded protein homologous to Pre proteins.
- The pMV158-encoded protein is essential for transfer in L. lactis, suggesting a role in mobilization.
Conclusions:
- Plasmid transfer mechanisms differ significantly between Enterococcus faecalis and Lactococcus lactis.
- Lactococcus lactis possesses chromosomal factors that facilitate non-self-transmissible plasmid transfer.
- The pMV158-encoded Pre-like protein plays a crucial role in plasmid mobilization within Lactococcus lactis.