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Research article - Peer-reviewed, 2008

Genomic and genetic characterization of the bile stress response of probiotic Lactobacillus reuteri ATCC 55730

Whitehead, Kristi; Versalovic, James; Roos, Stefan; Britton, Robert A.


Probiotic bacteria encounter various stresses after ingestion by the host, including exposure to the low pH in the stomach and bile in the small intestine. The probiotic microorganism Lactobacillus reuteri ATCC 55730 has previously been shown to survive in the human small intestine. To address how L. reuteri can resist bile stress, we performed microarray experiments to determine gene expression changes that occur when the organism is exposed to physiological concentrations of bile. A wide variety of genes that displayed differential expression in the presence of bile indicated that the cells were dealing with several types of stress, including cell envelope stress, protein denaturation, and DNA damage. Mutations in three genes were found to decrease the strain's ability to survive bile exposure: lr1864, a Clp chaperone; lr0085, a gene of unknown function; and lr1516, a putative esterase. Mutations in two genes that form an operon, lr1584 (a multidrug resistance transporter in the major facilitator superfamily) and lr1582 (unknown function), were found to impair the strain's ability to restart growth in the presence of bile. This study provides insight into the possible mechanisms that L. reuteri ATCC 55730 may use to survive and grow in the presence of bile in the small intestine.

Published in

Applied and Environmental Microbiology
2008, Volume: 74, number: 6, pages: 1812-1819

    SLU Authors

    Sustainable Development Goals

    SDG3 Good health and well-being

    UKÄ Subject classification

    Food Science

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