title: A single mutation in the gene responsible for the mucoid phenotype of Bifidobacterium animalis subsp. lactis confers surface and functional characteristics.
abstract: Exopolysaccharides (EPS) are extracellular carbohydrate polymers synthesized by a large variety of bacteria. Their physiological functions have been extensively studied, but many of their roles have not yet been elucidated. We have sequenced the genomes of two isogenic strains of Bifidobacterium animalis subsp. lactis that differ in their EPS-producing phenotype. The original strain displays a nonmucoid appearance, and the mutant derived thereof has acquired a mucoid phenotype. The sequence analysis of their genomes revealed a nonsynonymous mutation in the gene Balat_1410, putatively involved in the elongation of the EPS chain. By comparing a strain from which this gene had been deleted with strains containing the wild-type and mutated genes, we were able to show that each strain displays different cell surface characteristics. The mucoid EPS synthesized by the strain harboring the mutation in Balat_1410 provided higher resistance to gastrointestinal conditions and increased the capability for adhesion to human enterocytes. In addition, the cytokine profiles of human peripheral blood mononuclear cells and ex vivo colon tissues suggest that the mucoid strain could have higher anti-inflammatory activity. Our findings provide relevant data on the function of Balat_1410 and reveal that the mucoid phenotype is able to alter some of the most relevant functional properties of the cells.
authors.affiliation: Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute (IPLA-CSIC), Villaviciosa, Asturias, Spain.
authors.forename: Claudio
authors.initials: C
authors.lastname: Hidalgo-Cantabrana
authors.affiliation: Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute (IPLA-CSIC), Villaviciosa, Asturias, Spain.
authors.forename: Borja
authors.initials: B
authors.lastname: Sánchez
authors.affiliation: Human Microbiology, Nestlé Research Center Vers-chez-les-Blanc, Lausanne, Switzerland.
authors.forename: Pablo
authors.initials: P
authors.lastname: Álvarez-Martín
authors.affiliation: Immunology Area, Department of Functional Biology, University of Oviedo, Oviedo, Asturias, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: López
authors.affiliation: Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute (IPLA-CSIC), Villaviciosa, Asturias, Spain.
authors.forename: Noelia
authors.initials: N
authors.lastname: Martínez-Álvarez
authors.affiliation: Human Microbiology, Nestlé Research Center Vers-chez-les-Blanc, Lausanne, Switzerland.
authors.forename: Michele
authors.initials: M
authors.lastname: Delley
authors.affiliation: Surgery Department, University Hospital Vall d'Hebron, Barcelona, Spain.
authors.forename: Marc
authors.initials: M
authors.lastname: Martí
authors.affiliation: Department of Gastroenterology, Digestive System Research Unit, Institut de Recerca Vall d'Hebron, University Hospital Vall d'Hebron, Universitat Autónoma de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain.
authors.forename: Encarna
authors.initials: E
authors.lastname: Varela
authors.affiliation: Immunology Area, Department of Functional Biology, University of Oviedo, Oviedo, Asturias, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Suárez
authors.affiliation: Department of Gastroenterology, Digestive System Research Unit, Institut de Recerca Vall d'Hebron, University Hospital Vall d'Hebron, Universitat Autónoma de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Antolín
authors.affiliation: Department of Gastroenterology, Digestive System Research Unit, Institut de Recerca Vall d'Hebron, University Hospital Vall d'Hebron, Universitat Autónoma de Barcelona, Barcelona, Spain Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Spain.
authors.forename: Francisco
authors.initials: F
authors.lastname: Guarner
authors.affiliation: Human Microbiology, Nestlé Research Center Vers-chez-les-Blanc, Lausanne, Switzerland.
authors.forename: Bernard
authors.initials: B
authors.lastname: Berger
authors.affiliation: Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute (IPLA-CSIC), Villaviciosa, Asturias, Spain.
authors.forename: Patricia
authors.identifier: http://orcid.org/0000-0001-6158-9320
authors.initials: P
authors.lastname: Ruas-Madiedo
authors.affiliation: Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute (IPLA-CSIC), Villaviciosa, Asturias, Spain amargolles@ipla.csic.es.
authors.forename: Abelardo
authors.initials: A
authors.lastname: Margolles
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001644:Bifidobacterium / Q000235:genetics* / Q000378:metabolism; D005838:Genotype; D009154:Mutation; D010641:Phenotype; D011135:Polysaccharides, Bacterial / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D011135:Polysaccharides, Bacterial