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Potassium ion efflux induced by cationic compounds in yeast
E Enríquez-Freire1, R López, A Peña
1Departamento de Genética y Biología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado 70-600, 04510, México, D.F., Mexico.
Biochimica Et Biophysica Acta
|April 21, 1999
Summary
Cationic compounds induce potassium efflux in yeast, requiring glucose and cell surface binding. Different compounds activate distinct efflux mechanisms, highlighting membrane transport complexity.
Area of Science:
- * Yeast cell physiology and membrane transport mechanisms.
- * Biochemistry and biophysics of ion transport.
- * Effects of cationic compounds on cellular processes.
Background:
- * Potassium (K+) is a vital intracellular cation influencing cell volume, membrane potential, and metabolic functions.
- * Understanding potassium efflux is crucial for comprehending yeast cell homeostasis and response to external stimuli.
- * Cationic compounds can interact with cell membranes, potentially altering ion permeability.
Purpose of the Study:
- * To investigate and differentiate the mechanisms of potassium efflux induced by various cationic compounds in yeast.
- * To elucidate the role of cell surface charge, substrate availability, and osmotic conditions in cationic compound-induced potassium efflux.
- * To identify specific transport systems involved in potassium loss.
Main Methods:
- * Induction of potassium efflux using different cationic compounds (terbium chloride, DEAE-dextran, dihydrostreptomycin, ethidium bromide).
- * Measurement of potassium efflux under varying conditions, including glucose availability, cell surface charge, and osmotic pressure.
- * Assessment of cell integrity and potassium uptake inhibition.
Main Results:
- * All tested cationic compounds induced potassium efflux requiring glucose as a substrate.
- * Efflux mechanisms varied, with terbium chloride suggesting K+/H+ antiporter involvement and DEAE-dextran/dihydrostreptomycin indicating dependence on cell potassium content and osmotic sensitivity.
- * DEAE-dextran did not cause cell disruption, while dihydrostreptomycin may inhibit potassium uptake.
Conclusions:
- * Cationic compounds trigger diverse potassium efflux pathways in yeast, dependent on compound properties and cellular conditions.
- * The observed potassium efflux is a membrane phenomenon, generally reversible and not always associated with cell lysis.
- * These findings provide insights into yeast membrane transport regulation and response to cationic agents.