title: Na+ and K+ transport by 4-chlorophenylurethane-monensin in Enterococcus hirae de-energized and energized cells studied by 23Na-NMR and K+ atomic absorption.
abstract: Na+ and K+ movements induced by 4-chlorophenylurethane-monensin, which presents an inverted ion selectivity (K+ > Na+) in model systems compared with monensin, were followed on Enterococcus hirae cells by 23Na-NMR and K+ atomic absorption. For de-energized cells, the urethane derivative is much more selective for K+ than monensin, but only at low concentrations (10(-3)-10(-4) mM). For higher concentrations, as previously shown for monensin, the sodium and potassium movements are driven by the ion gradients present. On energized cells, both K+ and Na+ gradients were highly perturbed, and this can be related to the higher toxicity in mice and bacteria for this derivative.
authors.affiliation: Laboratoire de Chimie Organique Biologique, U.R.A. 485 du CNRS, Université Blaise Pascal, Aubiere, France.
authors.forename: F
authors.initials: F
authors.lastname: Rabaste
authors.forename: G
authors.initials: G
authors.lastname: Jeminet
authors.forename: G
authors.initials: G
authors.lastname: Dauphin
authors.forename: A M
authors.initials: AM
authors.lastname: Delort
mesh_terms: D001692:Biological Transport; D002219:Carbamates / Q000494:pharmacology*; D016983:Enterococcus / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008954:Models, Biological; D008985:Monensin / Q000031:analogs & derivatives*; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D013054:Spectrophotometry, Atomic
chemical_list: D002219:Carbamates; C084140:4-chlorophenylurethane; D008985:Monensin; D012964:Sodium; D011188:Potassium