title: EPS-SJ Exopolisaccharide Produced by the Strain Lactobacillus paracasei subsp. paracasei BGSJ2-8 Is Involved in Adhesion to Epithelial Intestinal Cells and Decrease on E. coli Association to Caco-2 Cells.
abstract: The aim of this study was to determine the role of an exopolysaccharide produced by natural dairy isolate Lactobacillus paracasei subsp. paracasei BGSJ2-8, in the adhesion to intestinal epithelial cells and a decrease in Escherichia coli's association with Caco-2 cells. Annotation of the BGSJ2-8 genome showed the presence of a gene cluster, epsSJ, which encodes the biosynthesis of the strain-specific exopolysaccharide EPS-SJ, detected as two fractions (P1 and P2) by size exclusion chromatography (SEC) coupled with multi-angle laser light scattering (MALLS) detection. SEC-MALLS analysis revealed that an EPS-SJ(-) mutant (EPS7, obtained by insertion mutagenesis of the glps_2198 gene encoding primary glycosyltransferase) does not produce the P2 fraction of EPS-SJ. Transmission electron microscopy showed that EPS7 mutant has a thinner cell wall compared to the EPS-SJ(+) strain BGSJ2-83 (a plasmid free-derivative of BGSJ2-8). Interestingly, strain BGSJ2-83 showed higher adhesion to Caco-2 epithelial intestinal cell line than the EPS7 mutant. Accordingly, BGSJ2-83 effectively reduced E. coli ATCC25922's association with Caco-2 cells, while EPS7 did not show statistically significant differences. In addition, the effect of EPS-SJ on the proliferation of lymphocytes in gastrointestinal associated lymphoid tissue (GALT) was tested and the results showed that the reduction of GALT lymphocyte proliferation was higher by BGSJ2-83 than by the mutant. To the best of our knowledge this is the first report indicating that the presence of EPS (EPS-SJ) on the surface of lactobacilli can improve communication between bacteria and intestinal epithelium, implying its possible role in gut colonization.
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia.
authors.forename: Milica
authors.initials: M
authors.lastname: Živković
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia.
authors.forename: Marija S
authors.initials: MS
authors.lastname: Miljković
authors.affiliation: Instituto de Productos Lácteos de Asturias - Consejo Superior de Investigaciones Científicas Villaviciosa, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Ruas-Madiedo
authors.affiliation: Center for Electron Microscopy, Faculty of Biology, University of Belgrade Belgrade, Serbia.
authors.forename: Milica B
authors.initials: MB
authors.lastname: Markelić
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia.
authors.forename: Katarina
authors.initials: K
authors.lastname: Veljović
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia.
authors.forename: Maja
authors.initials: M
authors.lastname: Tolinački
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Soković
authors.affiliation: Center for Electron Microscopy, Faculty of Biology, University of Belgrade Belgrade, Serbia.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Korać
authors.affiliation: Laboratory for Molecular Microbiology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade Belgrade, Serbia.
authors.forename: Nataša
authors.initials: N
authors.lastname: Golić
keywords: E. coli association; EPS-SJ; GALT lymphocytes; Lactobacillus paracasei; adhesion