RRC ID 5558
著者 Fang F, Li Y, Bumann M, Raftis EJ, Casey PG, Cooney JC, Walsh MA, O'Toole PW.
タイトル Allelic variation of bile salt hydrolase genes in Lactobacillus salivarius does not determine bile resistance levels.
ジャーナル J Bacteriol
Abstract Commensal lactobacilli frequently produce bile salt hydrolase (Bsh) enzymes whose roles in intestinal survival are unclear. Twenty-six Lactobacillus salivarius strains from different sources all harbored a bsh1 allele on their respective megaplasmids. This allele was related to the plasmid-borne bsh1 gene of the probiotic strain UCC118. A second locus (bsh2) was found in the chromosomes of two strains that had higher bile resistance levels. Four Bsh1-encoding allele groups were identified, defined by truncations or deletions involving a conserved residue. In vitro analyses showed that this allelic variation was correlated with widely varying bile deconjugation phenotypes. Despite very low activity of the UCC118 Bsh1 enzyme, a mutant lacking this protein had significantly lower bile resistance, both in vitro and during intestinal transit in mice. However, the overall bile resistance phenotype of this and other strains was independent of the bsh1 allele type. Analysis of the L. salivarius transcriptome upon exposure to bile and cholate identified a multiplicity of stress response proteins and putative efflux proteins that appear to broadly compensate for, or mask, the effects of allelic variation of bsh genes. Bsh enzymes with different bile-degrading kinetics, though apparently not the primary determinants of bile resistance in L. salivarius, may have additional biological importance because of varying effects upon bile as a signaling molecule in the host.
巻・号 191(18)
ページ 5743-57
公開日 2009-9-1
DOI 10.1128/JB.00506-09
PII JB.00506-09
PMID 19592587
PMC PMC2737978
MeSH Alleles* Amidohydrolases / genetics* Amidohydrolases / metabolism Animals Bacterial Proteins Bile Acids and Salts / metabolism Bile Acids and Salts / pharmacology* Drug Resistance, Bacterial* Genetic Variation* Humans Intestines / microbiology Lactobacillus / drug effects Lactobacillus / enzymology* Lactobacillus / genetics Lactobacillus / growth & development Mice Microbial Sensitivity Tests Molecular Sequence Data Mutation Oligonucleotide Array Sequence Analysis Phylogeny
IF 3.006
引用数 48
WOS 分野 MICROBIOLOGY
リソース情報
一般微生物 JCM1046 JCM1230