title: Mechanism of energization of uptake of the fluorescent dye 2-(4-dimethylaminostyryl)-1-ethylpyridinium cation [DMP+] into an acrA strain of Escherichia coli.
abstract: The mechanism of uptake of the fluorescent dye 2-(4-dimethylaminostyryl)-1-ethylpyridinium cation (DMP+) into cells and vesicles of the acrA strain AS-1 of Escherichia coli was examined. Uptake was energized by substrate oxidation and discharged by uncouplers. Uptake was enhanced by the presence of tetraphenylphosphonium cation, tetraphenylboron anion and tributyltin chloride, which may inhibit the efflux system for DMP+. Uptake was inhibited by 5-methoxyindole-2-carboxylic acid (MIC). By the use of ionophores with right-side-out vesicles loaded with monovalent cations it was shown that DMP+ uptake could be driven both by the establishment of a membrane potential across the vesicle membrane and by a H+/DMP+ antiport system. Attempts to demonstrate the latter mechanism in everted membrane vesicles were unsuccessful.
authors.affiliation: Department of Biochemistry, University of British Columbia, Vancouver, Canada.
authors.forename: E G
authors.initials: EG
authors.lastname: Sedgwick
authors.forename: P D
authors.initials: PD
authors.lastname: Bragg
mesh_terms: D000818:Animals; D002412:Cations; D002463:Cell Membrane Permeability / Q000187:drug effects; D004594:Electrophysiology; D004734:Energy Metabolism; D004926:Escherichia coli / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D008930:Mitochondria, Liver / Q000378:metabolism; D009550:Nigericin / Q000494:pharmacology; D009861:Onium Compounds / Q000378:metabolism; D009943:Organophosphorus Compounds / Q000378:metabolism; D011726:Pyridinium Compounds / Q000378:metabolism*; D051381:Rats; D013775:Tetraphenylborate / Q000494:pharmacology; D014220:Trialkyltin Compounds / Q000494:pharmacology; D014634:Valinomycin / Q000494:pharmacology
chemical_list: D002412:Cations; D005456:Fluorescent Dyes; D007211:Indoles; D009861:Onium Compounds; D009943:Organophosphorus Compounds; D011726:Pyridinium Compounds; D014220:Trialkyltin Compounds; D014634:Valinomycin; C008400:5-methoxyindole-2-carboxylic acid; C025042:2-(dimethylaminostyryl)-1-ethylpyridinium; D013775:Tetraphenylborate; C011559:tributyltin; D009550:Nigericin; C013289:tetraphenylphosphonium