title: Heterologous expression of BetL, a betaine uptake system, enhances the stress tolerance of Lactobacillus salivarius UCC118.
abstract: Given the increasing commercial and clinical relevance of probiotic cultures, improving the technological robustness of what are often process-sensitive cultures is an important biological goal. The nisin-controlled expression system was used to direct the heterologous expression of the listerial betaine uptake system BetL in the probiotic strain Lactobacillus salivarius UCC118. Following nisin induction, strains expressing betL exhibited a significant increase in resistance to several stresses, including elevated osmo-, cryo-, baro-, and chill tolerance, as well as increased resistance to spray- and freeze-drying. The ability to confer additional stress tolerance on a probiotic culture may be an important step in delivering viable cultures for maximal efficacy.
authors.affiliation: Department of Microbiology, University College, Cork, Ireland.
authors.forename: Vivien M
authors.initials: VM
authors.lastname: Sheehan
authors.forename: Roy D
authors.initials: RD
authors.lastname: Sleator
authors.forename: Gerald F
authors.initials: GF
authors.lastname: Fitzgerald
authors.forename: Colin
authors.initials: C
authors.lastname: Hill
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001622:Betaine / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D015169:Colony Count, Microbial; D005615:Freezing; D018869:Heat-Shock Response; D007778:Lactobacillus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D008089:Listeria monocytogenes / Q000235:genetics / Q000378:metabolism; D009561:Nisin / Q000494:pharmacology; D009994:Osmolar Concentration
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C119698:BetL protein, Listeria monocytogenes; D002352:Carrier Proteins; D009561:Nisin; D001622:Betaine