title: Adhesions of extracellular surface-layer associated proteins in Lactobacillus M5-L and Q8-L.
abstract: Surface-layer associated proteins (SLAP) that envelop Lactobacillus paracasei ssp. paracasei M5-L and Lactobacillus casei Q8-L cell surfaces are involved in the adherence of these strain to the human intestinal cell line HT-29. To further elucidate some of the properties of these proteins, we assessed the yields and expressions of SLAP under different incubation conditions. An efficient and selective extraction of SLAP was obtained when cells of Lactobacillus were treated with 5 M LiCl at 37°C in aerobic conditions. The SLAP of Lactobacillus M5-L and Q8-L in cell extracts were visualized by SDS-PAGE and identified by Western blotting with sulfo-N-hydroxysuccinimide-biotin-labeled HT-29 cells as adhesion proteins. Atomic force microscopy contact imaging revealed that Lactobacillus strains M5-L and Q8-L normally display a smooth, homogeneous surface, whereas the surfaces of M5-L and Q8-L treated with 5 M LiCl were rough and more heterogeneous. Analysis of adhesion forces revealed that the initial adhesion forces of 1.41 and 1.28 nN obtained for normal Lactobacillus M5-L and Q8-L strains, respectively, decreased to 0.70 and 0.48 nN, respectively, following 5 M LiCl treatment. Finally, the dominant 45-kDa protein bands of Lactobacillus Q8-L and Lactobacillus M5-L were identified as elongation factor Tu and surface antigen, respectively, by liquid chromatography-tandem mass spectrometry.
authors.affiliation: Department of Food Science and Engineering, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin150090, China; School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin150090, China.
authors.forename: Yingchun
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Food Science and Engineering, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin150090, China.
authors.forename: Xinling
authors.initials: X
authors.lastname: Xiang
authors.affiliation: Department of Food Science and Engineering, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin150090, China.
authors.forename: Qianhui
authors.initials: Q
authors.lastname: Lu
authors.affiliation: Department of Food Science and Engineering, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin150090, China. Electronic address: zyc229@163.com.
authors.forename: Lanwei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin150090, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Ma
authors.affiliation: Department of Food Science and Engineering, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin150090, China.
authors.forename: Linlin
authors.initials: L
authors.lastname: Wang
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001710:Biotin / Q000031:analogs & derivatives; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D019073:HT29 Cells; D006801:Humans; D007422:Intestines; D007778:Lactobacillus / Q000502:physiology*; D008562:Membrane Glycoproteins; D013388:Succinimides
chemical_list: D001426:Bacterial Proteins; D008562:Membrane Glycoproteins; C055764:S-layer proteins; D013388:Succinimides; C065130:sulfo-N-hydroxysuccinimide-biotin; D001710:Biotin
keywords: Lactobacillus; adhesion; identification; surface-layer associated proteins