title: Efflux of choline and glycine betaine from osmoregulating cells of Escherichia coli.
abstract: We present evidence that glycine betaine (betaine) which was synthesized from choline was excreted and reaccumulated in osmoregulating cells of Escherichia coli. Choline which was accumulated in bet mutants defective in betaine synthesis was shown to be excreted in response to betaine uptake. Our data suggest that E. coli has efflux systems for betaine and choline which are independent of the uptake systems for these metabolites. The ProU system of E. coli, but not that of Salmonella typhimurium, can mediate low-affinity choline uptake.
authors.affiliation: Norwegian College of Fishery Sciences, University of Tromsø.
authors.forename: T
authors.initials: T
authors.lastname: Lamark
authors.forename: O B
authors.initials: OB
authors.lastname: Styrvold
authors.forename: A R
authors.initials: AR
authors.lastname: Strøm
mesh_terms: D001622:Betaine / Q000378:metabolism*; D001693:Biological Transport, Active; D002794:Choline / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D005798:Genes, Bacterial; D007700:Kinetics; D009154:Mutation; D014882:Water-Electrolyte Balance
chemical_list: D001622:Betaine; D002794:Choline