title: Characterization of a plasmid involved with cointegrate formation and lactose metabolism in Lactococcus lactis subsp. lactis OZS1.
abstract: A 55 kilobase (kb) plasmid (pOZS550) in the non-clumping Lactococcus lactis subsp. lactis strain OZS1 carrying genes for lactose metabolism was characterised. A mobilizable cointegrate plasmid which is formed between pOZS550 and pOZS448 carries the necessary information for conjugation and transfer. Cointegrate formation was found to involve an insertional element located on pOZS550. The insertion sequence was found to be identical to ISS1 located on pSK08 in the clumping L. lactis subsp. lactis strain ML3. Restriction maps of pOZS550 and pSK08 were similar suggesting a close ancestral relationship, although pSK08, in addition to the lactose metabolism genes, expressed genes for proteinase activity and cell clumping, which were not expressed by pOZS550, and carried two copies of ISS1 compared to one on pOZS550. Furthermore, hybridization of the 18 base pair inverted repeat, of the insertion sequence, with various L. lactis subsp. lactis strains and two L. lactis subsp. cremoris strains showed moderate to strong hybridization to one plasmid in each organism.
authors.affiliation: Department of Nutrition and Food Sciences, Utah State University.
authors.forename: A J
authors.initials: AJ
authors.lastname: Smigielski
mesh_terms: D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D003227:Conjugation, Genetic; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry; D015964:Gene Expression Regulation, Bacterial; D013294:Lactococcus lactis / Q000235:genetics*; D007785:Lactose / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010957:Plasmids; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D007785:Lactose