A triggered-suicide system designed as a defense against bacteriophages.

摘要: A novel bacteriophage protection system for Lactococcus lactis based on a genetic trap, in which strictly phage-inducible promoter isolated from the lytic phage phi31 is used to activate bacterial suicide after infection, was developed. The lethal gene of consists three-gene restriction cassette LlaIR+, across wide range gram-positive bacteria. trigger (phi31P) and LlaIR+ were cloned Escherichia coli high-copy-number replicon generate pTRK414H. Restriction activity not apparent E. or L. prior infection. In challenges lactis(pTRK414H) with phi31, efficiency plaquing lowered 10(-4) accompanied by fourfold reduction burst size. Center-of-infection assays revealed that only 15% infected cells released progeny phage. addition phi31P/LlaIR+ also inhibited four phi31-derived recombinant phages at levels least 10-fold greater than phi31. phi31P/LlaIR+-based genetically engineered form abortive infection traps eliminates potentially evolving fermentation environments destroying genome killing propagation host. This type phage-triggered could be designed any bacterium-phage combination, given universal an inducible triggered infecting bacteriophage.