Back to Search
Start Over
Contribution of three bile-associated loci, bsh, pva, and btlB, to gastrointestinal persistence and bile tolerance of Listeria monocytogenes
- Source :
- Infection and immunity. 73(2)
- Publication Year :
- 2005
-
Abstract
- Listeria monocytogenes must resist the deleterious actions of bile in order to infect and subsequently colonize the human gastrointestinal tract. The molecular mechanisms used by the bacterium to resist bile and the influence of bile on pathogenesis are as yet largely unexplored. This study describes the analysis of three genes— bsh , pva , and btlB —previously annotated as bile-associated loci in the sequenced L. monocytogenes EGDe genome (lmo2067, lmo0446, and lmo0754, respectively). Analysis of deletion mutants revealed a role for all three genes in resisting the acute toxicity of bile and bile salts, particularly glycoconjugated bile salts at low pH. Mutants were unaffected in the other stress responses examined (acid, salt, and detergents). Bile hydrolysis assays demonstrate that L. monocytogenes possesses only one bile salt hydrolase gene, namely, bsh . Transcriptional analyses and activity assays revealed that, although it is regulated by both PrfA and σ B , the latter appears to play the greater role in modulating bsh expression. In addition to being incapable of bile hydrolysis, a sigB mutant was shown to be exquisitely sensitive to bile salts. Furthermore, increased expression of sigB was detected under anaerobic conditions and during murine infection. A gene previously annotated as a possible penicillin V amidase ( pva ) or bile salt hydrolase was shown to be required for resistance to penicillin V but not penicillin G but did not demonstrate a role in bile hydrolysis. Finally, animal (murine) studies revealed an important role for both bsh and btlB in the intestinal persistence of L. monocytogenes .
- Subjects :
- Time Factors
Immunology
Mutant
Sigma Factor
Penicillin amidase
medicine.disease_cause
Microbiology
digestive system
Amidase
Mice
Listeria monocytogenes
Bacterial Proteins
Sigma factor
medicine
Animals
Bile
chemistry.chemical_classification
biology
Human gastrointestinal tract
biology.organism_classification
Molecular Pathogenesis
Enzymes
Gastrointestinal Tract
Infectious Diseases
medicine.anatomical_structure
Enzyme
chemistry
Biochemistry
Mutation
Trans-Activators
Parasitology
Penicillin Amidase
Bacteria
Peptide Termination Factors
Subjects
Details
- ISSN :
- 00199567
- Volume :
- 73
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- Infection and immunity
- Accession number :
- edsair.doi.dedup.....d5c5115a94b9287c27016f804388e7cb