title: Effective plasmid pX3 transduction in Lactobacillus delbrueckii by bacteriophage LL-H.
abstract: High-frequency plasmid transductions in Lactobacillus delbrueckii subsp. lactis and subsp. bulgaricus strains mediated by pac-type bacteriophages were observed and further investigated. The frequency of plasmid transduction by phages LL-H and LL-S attained levels of from 0.10 to about 1 with plasmid p X 3, but only about 2 x 10(-2) with plasmid pJK650. Infection of L. delbrueckii subsp. lactis strain LKT(pX3) or ATCC 15808(pX3) with phage LL-H resulted in intensive concatemerization of plasmid pX3, and most progeny phage particles contained concatemers of plasmid DNA instead of phage LL-H DNA. The synthesis of phage LL-H DNA was depressed. No evident homology or recombination was observed between phage LL-H DNA and plasmid pX3. The unusually high frequency of plasmid pX3 transduction by phage LL-H could be considered to result from specific interaction(s) between a particular phage and plasmid. These interactions may include pX3-mediated blockage of phage LL-H DNA replication and effective use of a particular pac-like site located about 1 kb from BglII in the smaller NdeI-BglII fragment of plasmid pX3. Phage LL-H together with plasmid vector pX3 could be used as effective plasmid transduction tools for genetic engineering of L. delbrueckii subsp. lactis and subsp. bulgaricus strains.
authors.affiliation: Department of Biology, University of Oulu, Linnanmaa campus, P.O. Box 3000, FIN-90014 Oulu, Finland.
authors.forename: Victor
authors.initials: V
authors.lastname: Ravin
authors.forename: Takashi
authors.initials: T
authors.lastname: Sasaki
authors.forename: Liisa
authors.initials: L
authors.lastname: Räisänen
authors.forename: Katja-Anneli
authors.initials: KA
authors.lastname: Riipinen
authors.forename: Tapani
authors.initials: T
authors.lastname: Alatossava
mesh_terms: D001435:Bacteriophages / Q000235:genetics / Q000502:physiology*; D004261:DNA Replication; D004262:DNA Restriction Enzymes / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics; D005818:Genetic Engineering; D048668:Lactobacillus delbrueckii / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids / Q000235:genetics*; D014161:Transduction, Genetic; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D004262:DNA Restriction Enzymes