[Effect of Na+ and K+ ions on the luminescence of intact Vibrio harveyi cells at different pH values].
The bioluminescent activity of intact Vibrio harveyi cells loaded with different concentrations of NaCl and KCl at different pH values was studied. In the pH range of 6.5-8.5, the effect of Na+ was significantly higher than that of K+ at all concentrations studied. Maximum luminescent activity was observed in cells loaded with 0.68 M NaCl. When Na+ was nonuniformly distributed on the plasma membrane, the cell luminescence kinetics was nonstationary in the 20-min range: during incubation, the luminescence intensity increased at pH 6.5 and decreased at pH 8.5. The activation and damping rate constants depended on the Na+ gradient value. The maximum of luminescent activity shifted during incubation from pH 8.5 to 6.5-7.0. The luminescence kinetics in the systems with KCl was stationary; the maximum level of luminescence was observed in the pH range of 7.0-7.5. Under Na(+)-controlled conditions, the cell respiration and luminescence changed in synchronism. The protonophore CCP at a concentration of 20 microM completely inhibited luminescence at pH 6.5 and was ineffective at pH 8.5.
Vitukhnovskaia
L A
LA
Department of Microbiology, Biological Faculty, Moscow State University, Moscow, 119889 Russia.
Ismailov
A D
AD
D004305:Dose-Response Relationship, Drug; D006863:Hydrogen-Ion Concentration; D008163:Luminescent Measurements; D011189:Potassium Chloride / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D014733:Vibrio / Q000502:physiology*
D012965:Sodium Chloride; D011189:Potassium Chloride