The conjugative plasmid pTR2030 encodes two bacteriophage defense mechanisms in lactococci, restriction modification (R+/M+) and abortive infection (Hsp+).
pTR2030 is a conjugative plasmid which encodes resistance to bacteriophage in lactococci by a mechanism that aborts the phage infection (Hsp+). Subcloning and in vivo deletion events showed that two independent mechanisms of resistance are located on a 13.6-kilobase Bg/II fragment cloned in pSA3; one mechanism is responsible for the abortive infection, and the other incodes a restriction modification system. The introduction of pTR2030 or the recombinant plasmid pTK6 resulted in the loss of a resident restriction modification plasmid in Lactococcus lactis NCK202 which was not previously identified.
Hill
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Department of Food Science, North Carolina State University, Raleigh 27695-7624.
Pierce
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Klaenhammer
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D001435:Bacteriophages / Q000235:genetics* / Q000254:growth & development; D003227:Conjugation, Genetic; D006360:Heat-Shock Proteins / Q000235:genetics*; D013294:Lactococcus lactis / Q000235:genetics*; D010957:Plasmids; D015183:Restriction Mapping; D010948:Viral Plaque Assay
D006360:Heat-Shock Proteins