title: Fermentation product butane 2,3-diol induces Ca2+ transients in E. coli through activation of lanthanum-sensitive Ca2+ channels.
abstract: The results here are the first demonstration of a physiological agonist opening Ca2+ channels in bacteria. Bacteria in the gut ferment glucose and other substrates, producing alcohols, diols, ketones and acids, that play a key role in lactose intolerance, through the activation of Ca2+ and other ion channels in host cells and neighbouring bacteria. Here we show butane 2,3-diol (5-200mM; half maximum 25mM) activates Ca2+ transients in E. coli, monitored by aequorin. Ca2+-transient magnitude depended on external Ca2+ (0.1-10mM). meso-Butane 2,3-diol was approximately twice as potent as 2R,3R (-) and 2S,3S (+) butane 2,3-diol. There were no detectable effects on cytosolic free Ca2+ of butane 1,3-diol, butane 1,4-diol and ethylene glycol. The glycerol fermentation product propane 1,3-diol only induced significant Ca2+ transients in 10mM external Ca2. Ca2+ butane 2,3-diol Ca2+ transients were due to activation of Ca2+ influx, followed by activation of Ca2+ efflux. The effect of butane 2,3-diol was abolished by La3+, and markedly reduced as a function of growth phase. These results were consistent with butane 2,3-diol activating a novel La3+-sensitive Ca2+ channel. They have important implications for the role of butane 2,3-diol and Ca2+ in bacterial-host cell signalling.
authors.affiliation: Department of Medical Biochemistry and Immunology, School of Medicine, Tenovus Building, Cardiff University, Heath Park, Cardiff CF14 4XN, UK. campbellak@cf.ac.uk
authors.forename: Anthony K
authors.initials: AK
authors.lastname: Campbell
authors.forename: Riffat
authors.initials: R
authors.lastname: Naseem
authors.forename: Kenneth
authors.initials: K
authors.lastname: Wann
authors.forename: I Barry
authors.initials: IB
authors.lastname: Holland
authors.forename: Stephanie B
authors.initials: SB
authors.lastname: Matthews
mesh_terms: D002072:Butylene Glycols / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D020013:Calcium Signaling; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli; D005285:Fermentation; D007811:Lanthanum / Q000494:pharmacology*; D011407:Propane / Q000494:pharmacology; D013237:Stereoisomerism
chemical_list: D002072:Butylene Glycols; D015220:Calcium Channels; D007811:Lanthanum; D002118:Calcium; D011407:Propane