title: Lactobacillus reuteri 100-23 modulates urea hydrolysis in the murine stomach.
abstract: Comparisons of in vivo (mouse stomach) and in vitro (laboratory culture) transcriptomes of Lactobacillus reuteri strain 100-23 were made by microarray analysis. These comparisons revealed the upregulation of genes associated with acid tolerance, including urease production, in the mouse stomach. Inactivation of the ureC gene reduced the acid tolerance of strain 100-23 in vitro, and the mutant was outcompeted by the wild type in the gut of ex-Lactobacillus-free mice. Urine analysis showed that stable isotope-labeled urea, administered by gavage, was metabolized to a greater extent in Lactobacillus-free mice than animals colonized by strain 100-23. This surprising observation was associated with higher levels of urease activity and fecal-type bacteria in the stomach digesta of Lactobacillus-free mice. Despite the modulation of urea hydrolysis in the stomach, recycling of urea nitrogen in the murine host was not affected since the essential amino acid isoleucine, labeled with a stable isotope, was detected in the livers of both Lactobacillus-free and 100-23-colonized animals. Therefore, our experiments reveal a new and unexpected impact of Lactobacillus colonization on urea hydrolysis in the murine gut.
authors: Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
authors: Charlotte M
authors: CM
authors: Wilson
authors: Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
authors: Diane
authors: D
authors: Loach
authors: Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
authors: Blair
authors: B
authors: Lawley
authors: The Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand.
authors: Tracey
authors: T
authors: Bell
authors: The Ferrier Research Institute, Victoria University of Wellington, Wellington, New Zealand.
authors: Ian M
authors: IM
authors: Sims
authors: School of Microbiology and Alimentary Pharmabiotic Centre, University College, Cork, Ireland.
authors: Paul W
authors: PW
authors: O'Toole
authors: School of Microbiology and Alimentary Pharmabiotic Centre, University College, Cork, Ireland.
authors: Aldert
authors: A
authors: Zomer
authors: Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand gerald.tannock@otago.ac.nz.
authors: Gerald W
authors: GW
authors: Tannock
mesh_terms: D000818:Animals; D005260:Female; D020869:Gene Expression Profiling; D023281:Genomics; D006868:Hydrolysis; D052200:Limosilactobacillus reuteri / Q000235:genetics* / Q000502:physiology; D008099:Liver / Q000382:microbiology; D008297:Male; D051379:Mice; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D013270:Stomach / Q000382:microbiology*; D059467:Transcriptome; D015854:Up-Regulation; D014508:Urea / Q000378:metabolism*; D014510:Urease / Q000235:genetics / Q000378:metabolism
chemical_list: D014508:Urea; D014510:Urease