The gastrointestinal microbiota is extremely complex and individual, and undoubtedly has a great impact on the well being of the host. Investigations of the composition of the intestinal microbiota are important parts of studies of the effect of the diet (including probiotics) on the host, but also for identifying correlations between the microbiota and different intestinal disorders. Investigations of the global composition of the microbiota as well as individual bacteria are important parts of our research and both culture independent and culture dependent methods are used.
Lactobacilli have been used for thousands of years to perform spontaneous fermentation of food and feed, but many of them are also part of the gastrointestinal microbiota. Today some lactobacilli are explored as probiotics, which means that they can give positive health effects when they are ingested. A variety of beneficial effects have been reported to be associated with the consumption of probiotics and the primary challenge for research within this field is now to verify health effects through good clinical studies and to explain the mechanisms of action behind probiotic effects. Another important challenge is to develop improved probiotic products. We do research on the probiotic bacterium Lactobacillus reuteri and our studies are focused on the genetics, physiology and ecology of this bacterium. We are also studying the behaviour and impact of L. reuteri in different models.
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Lactobacillus reuteri counteract colitis in DSS treated rats. The bacteria also maintains a functional mucosal barrier during DSS treatment, but does not affect the microbial composition and mucus layer dysfunction (Dicksved et al, 2012).
Gruppmedlemmar
Stefan Roos, forskare
Hans Jonsson, lektor
Shokoufeh Karimi, doktorand
Anton Pallin, doktorand
Some selected publications
Roos, S. and Jonsson, H. 2002. A high-molecular-mass cell-surface protein from Lactobacillus reuteri 1063 adheres to mucus components. Microbiology 148:433-42.
Pedersen, C., Jonsson, H., Lindberg, J.E. and Roos, S. 2004. A microbiological characterization of wet wheat distillers grain, with focus on isolation of lactobacilli with potential as probiotics. Applied and Environmental Microbiology 70(3): 1522-1527.
Roos, S., Engstrand, L. and Jonsson, H. 2005. Lactobacillus gastricus sp. nov., Lactobacillus antri sp. nov., Lactobacillus kalixensis sp. nov. and Lactobacillus ultunensis sp. nov, isolated from human stomach mucosa. Int. J. Syst. Evol. Microbiol. 55: 77-82.
Båth, K.*, Roos, S.*, Wall, T.* and Jonsson, H. 2005. The cell surface of Lactobacillus reuteri ATCC 55730 highlighted by identification of 126 extracellular proteins from the genome sequence. FEMS Microbiol. Letters, 253: 75-82.
Wall, T., Båth, K., Britton, R. A., Jonsson, H., Versalovic, J. and Roos, S. 2007. The Early Response to Acid Shock in Lactobacillus reuteri Involves the ClpL Chaperone and a Putative Cell Wall-Altering Esterase. Applied and Environmental Microbiology 73(12):3924-3935.
Rosander, A., Connolly, E. and Roos, S. 2008. Removal of antibiotic resistance plasmids from Lactobacillus reuteri ATCC 55730 and characterization of the resulting daughter strain L. reuteri DSM 17938. Applied and Environmental Microbiology 74:6032-6040.
Egervärn, M., Lindmark, H., Olsson, J. and Roos, S. 2010. Transferability of a tetracycline resistance gene from probiotic Lactobacillus reuteri to bacteria in the intestinal tract of humans. Antonie van Leeuwenhoek 97(2):189-200.
Savino, F., Cordisco, L., Tarasco, V., Palumeri, E., Calabrese, R., Oggero, R., Roos, S. and Matteuzzi, D. 2010. Lactobacillus reuteri DSM 17938 in infantile colic: a randomised, double-blind, placebo-controlled trial. Pediatrics 126(3):e526-533.
Walter, J., Britton, R. and Roos, S. 2011. Host-microbial symbiosis in the vertebrate gastrointestinal tract and the Lactobacillus reuteri paradigm. Proc. Natl. Acad. Sci. U.S.A. 108:4645-4652.
Dicksved, J., Schreiber, O., Willing, B., Petersson, J., Rang, S., Phillipson, M., Holm L. and Roos, S. 2012. Lactobacillus reuteri Maintains a Functional Mucosal Barrier During DSS Treatment Despite Mucus Layer Dysfunction. PLoS ONE 7(9): e46399.