title: Factors for bile tolerance in Lactococcus lactis: analysis by using plasmid variants.
abstract: The factors of bile tolerance (as one among the fundamental characteristics of probiotic bacteria) were determined in lactococci by using plasmid variants. Bile tolerance of Lactococcus lactis wild-type (WT) strains 527 and N7 (determined by viability counts on bile-containing agar) was equivalent to the corresponding plasmid-free derivatives. In contrast, L. lactis WT strain DRC1 had lower bile tolerance than its plasmid-free derivative DRC1021. Plasmid pDR1-1B, extracted from strain DRC1, was introduced into strain DRC1021 by co-transformation with the vector plasmid pGKV21 as an indicator. Strain DRC121 (DRC1021 harboring pGKV21) had good bile tolerance as did strain DRC1021, while strain DRC13 (DRC1021 harboring both pDR1-1B and pGKV21) did not. Fatty acid (FA) composition was different between strains DRC121 and DRC13. The plasmid pDR1-1B or plasmid profile and FA composition are key factors for bile tolerance of strain DRC1, and therefore changing the plasmid profile might be a way of modulating bile tolerance in lactococci.
authors: Functional Biomolecules Research Team, National Institute of Livestock and Grassland Science, Tsukuba, Ibaraki, 305-0901, Japan. anne@affrc.go.jp
authors: H
authors: H
authors: Kimoto-Nira
authors: M
authors: M
authors: Kobayahi
authors: M
authors: M
authors: Nomura
authors: T
authors: T
authors: Okamoto
authors: Y
authors: Y
authors: Fujita
mesh_terms: D001646:Bile; D001647:Bile Acids and Salts / Q000494:pharmacology*; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism; D013294:Lactococcus lactis / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics / Q000502:physiology*; D008954:Models, Biological; D010957:Plasmids / Q000235:genetics* / Q000378:metabolism
chemical_list: D001647:Bile Acids and Salts; D005227:Fatty Acids