Glucosyltransferase A (GtfA) and inulosucrase (Inu) of Lactobacillus reuteri TMW1.106 contribute to cell aggregation, in vitro biofilm formation, and colonization of the mouse gastrointestinal tract

• Published in: Microbiology (Society for General Microbiology) 2008-01, Vol.154 (1), p.72-80
• Main Authors: Walter, Jens, Schwab, Clarissa, Loach, Diane M, Ganzle, Michael G, Tannock, Gerald W
• Format: Article
• Language: English
• Subjects: Animals; Bacterial Adhesion; Bacteriology; Biofilms - growth & development; Biogenesis of cell structures, supramolecular organization; Biological and medical sciences; Colony Count, Microbial; Female; Fundamental and applied biological sciences. Psychology; Gastrointestinal Tract - microbiology; Gene Deletion; Glucosyltransferases - genetics; Glucosyltransferases - metabolism; Hexosyltransferases - genetics; Hexosyltransferases - metabolism; Intestinal Mucosa - microbiology; Lactobacillus; Lactobacillus johnsonii; Lactobacillus reuteri; Lactobacillus reuteri - enzymology; Lactobacillus reuteri - genetics; Lactobacillus reuteri - physiology; Male; Mice; Microbiology
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.2007/010637-0

1 Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand 2 Department of Agricultural Food and Nutritional Science, University of Alberta, Edmonton, Canada 3 Department of Food Science and Technology, University of Nebraska, Lincoln, NE 68583-0919, USA Correspondence Jens Walter jwalter2{at}unl.edu Members of the genus Lactobacillus are common inhabitants of the proximal gastrointestinal tract of animals such as mice, rats, chickens and pigs, where they form epithelial biofilms. Little is known about the traits that facilitate biofilm formation and gut colonization. This study investigated the ecological role of a glucosyltransferase (GtfA) and inulosucrase (Inu) of Lactobacillus reuteri TMW1.106 and a fructosyltransferase (FtfA) of L. reuteri LTH5448. In vitro experiments using isogenic mutants revealed that GtfA was essential for sucrose-dependent autoaggregation of L. reuteri TMW1.106 cells under acidic conditions, while inactivation of Inu slowed the formation of cell aggregates. Experiments using an in vitro biofilm assay showed that GtfA and Inu contributed to biofilm formation of L. reuteri TMW1.106. Experiments using ex- Lactobacillus- free mice revealed that the ecological performance of the inu mutant, but not of the gtfA or ftfA mutant, was reduced in the gastrointestinal tract when in competition with the parental strain. In the absence of competition, the gtfA mutant showed delayed colonization of the murine gut relative to the wild-type. In addition, the gtfA mutant showed reduced ecological performance in competition experiments with Lactobacillus johnsonii #21. From the evidence provided in this study we conclude that GtfA and Inu confer important ecological attributes of L. reuteri TMW1.106 and contribute to colonization of the mouse gastrointestinal tract. Abbreviations: EPS, extracellular polysaccharides; FOS, fructo-oligosaccharides; GOS, gluco-oligosaccharides; HoPS, homopolysaccharides; OS, oligosaccharides; TEM, transmission electron microscopy