title: Influence of gastrointestinal stress on autoinducer-2 activity of two Lactobacillus species.
abstract: Quorum sensing is a bacterial communication signalling system that regulates the expression of certain target genes with autoinducers in a cell density-dependent manner. The universal luxS-mediated quorum sensing using the autoinducer-2 (AI-2) signal is present in a wide variety of bacteria with only sparse information on probiotic lactobacilli. Effective probiotics should exhibit tolerance and adaptation to stress conditions typical of the GIT. Adhesion to human intestinal epithelial cells and competitive exclusion of pathogens are also considered important. The AI-2 signal system plays an important role in the response of probiotic lactobacilli to the surrounding environment. Intraspecies-related changes in quorum signalling in the GIT were determined by monitoring the AI-2 activity of two strains each of Lactobacillus rhamnosus and L. plantarum under various stress conditions. Modulation of the AI-2 activity of all the strains was induced by stress responses to pH, bile acid, temperature, osmotic pressure and starvation, and was both species- and strain-specific. AI-2 inhibition correlated with a reduction in the stress-related genes of L. rhamnosus. We therefore suggest that AI-2 quorum signalling of probiotic lactobacilli may represent one way of adapting to the host's ecosystem and of interacting within the intestinal environment.
authors.affiliation: School of Life Sciences, Handong Global University, Gyeongbuk 791-708, Pohang, Republic of Korea;
authors.forename: Soyoung
authors.initials: S
authors.lastname: Yeo
authors.affiliation: School of Life Sciences, Handong Global University, Gyeongbuk 791-708, Pohang, Republic of Korea;
authors.forename: Hyunjoon
authors.initials: H
authors.lastname: Park
authors.affiliation: School of Life Sciences, Handong Global University, Gyeongbuk 791-708, Pohang, Republic of Korea;
authors.forename: Yosep
authors.initials: Y
authors.lastname: Ji
authors.affiliation: School of Life Sciences, Handong Global University, Gyeongbuk 791-708, Pohang, Republic of Korea;
authors.forename: Soyoung
authors.initials: S
authors.lastname: Park
authors.affiliation: School of Life Sciences, Handong Global University, Gyeongbuk 791-708, Pohang, Republic of Korea;
authors.forename: Jaesik
authors.initials: J
authors.lastname: Yang
authors.affiliation: School of Life Sciences, Handong Global University, Gyeongbuk 791-708, Pohang, Republic of Korea;
authors.forename: Jieun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Food Science and Technology, Jomo Kenyatta University of Agriculture and Technology, PO Box 62000-00200, Nairobi, Kenya.
authors.forename: Julius M
authors.initials: JM
authors.lastname: Mathara
authors.affiliation: School of Life Sciences, Handong Global University, Gyeongbuk 791-708, Pohang, Republic of Korea;
authors.forename: Heuynkil
authors.initials: H
authors.lastname: Shin
authors.affiliation: School of Life Sciences, Handong Global University, Gyeongbuk 791-708, Pohang, Republic of Korea; wilhelm@woodapple.net.
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Holzapfel
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001422:Bacterial Adhesion / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000378:metabolism; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D006714:Homoserine / Q000031:analogs & derivatives* / Q000378:metabolism; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D007778:Lactobacillus / Q000235:genetics / Q000378:metabolism*; D007783:Lactones / Q000378:metabolism*; D019936:Probiotics; D053038:Quorum Sensing / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics; D013312:Stress, Physiological / Q000235:genetics*; D013552:Swine
chemical_list: D001426:Bacterial Proteins; D001647:Bile Acids and Salts; D007783:Lactones; C091088:N-octanoylhomoserine lactone; D006714:Homoserine; D013437:Carbon-Sulfur Lyases; C117753:LuxS protein, Bacteria
keywords: GIT stress; Lactobacillus; autoinducer-2; probiotics; quorum sensing