Dielectric properties of yeast cells: Effect of some ionic detergents on the plasma membranes

Abstract

Summary. Dielectric measurements were made on suspensions of yeast cells treated with two homologous series of sodium alkyl (Cs, C10, C12, C~4) sulfonates and alkyl (Cs, Clo, C12, C14, C16, C18) benzyl dimethyl ammonium chlorides over a frequency range of 10 kHz to 100 MHz. Dielectric dispersions observed for the suspensions of intact yeast cells are found to be reduced by treatment with these detergents, the reduction being accompanied by a decrease in packed volume of the ceils and by a leakage of intracellular compounds. The reduction of dielectric dispersions is considered to be caused by a decrease in volume of the cells in suspensions and an increase in conductivity of the cell membranes. An effect of the alkyl chain length of the detergents on the reduction of dielectric dispersions is also examined for these ionic detergents. The reducing effect shows the maximum at the alkyl chain C~4 for sodium alkyl sulfonates and at C16 for alkyl benzyl dimethyl ammonium chlorides. These results are consistent with hemolysis and bactericidal activity.It is known from many examples [8] that suspensions of biological cells show marked dielectric dispersions due to the Maxwell-Wagner mechanism, because the cells are covered with poorly conducting surface membranes. An increase in electrical conductivity of cell membranes gives rise to a reduction of the dielectric dispersions, so that the dielectric approach is useful to detect the change in membrane conductivity and the destruction of membranes caused by treatments with detergents, organic solvents, heat, freezing and thawing, and so on. However, little work has so far been reported on the effects of such treatments on the dielectric dispersions. The dielectric approach is particularly effective for cells covered with cell walls, since changes in dielectric properties of cell membranes can readily be examined without removing cell walls owing to little contribution of the cell walls to the dielectric dispersion of cell suspensions.

Dielectric observations on polystyrene microcapsules and the theoretical analysis with reference to interfacial polarization

“…The theory for concentrated suspensions 9 as well as that for dilute suspensions predicted a pair of relaxations as depicted in figure 2-(A). Nevertheless a number of biological cell suspensions as a kind of shelled sphere suspensions showed only one relaxation [10][11][12][13][14][15], which was assigned to the P-relaxation in figure 2-(A). The other Q-relaxation was reasonably understood to be too small to be observed.…”

“…The microcapsules prepared were fractionated (11) into fractions in different capsule sizes by passing through a series of meshscreens. Density Gradation Column.…”

“…Suspensions of biological cells and subcellular organella such as yeasts, E. coli, synaptosomes and mitochondria showed remarkable dielectric relaxations, which were caused by the shelled structure of these biological cells or organella [10][11][12][13][14][15]. Cell membrane capacitance, permittivity and conductivity of the cell interior were evaluated from these dielectric relaxation data by use of theories of interracial polarization for triphasic structure.…”

Dielectric Properties of Yeast Cells Expressed With the Motor Protein Prestin

“…His studies found that the low-frequency dielectric response of biological systems is enormous, but decreases rapidly with increasing frequency. More recently, Asami [2] and others [3] performed a variety of studies on live cell suspensions, including some on budding yeast (S. cerevisiae) that showed significant changes in dielectric response with time, reflecting cell respiration, metabolism, and reproduction. Prodan [4,5] performed theoretical modeling studies, predicting a correlation between the low frequency dielectric constant and the magnitude of the cellular transmembrane potential.…”

“…Dielectric spectroscopy is a powerful method for noninvasively characterizing the properties of biological systems [1][2][3][4][5][6][7][8][9][10][11][12]. It encompasses the frequency dependence of the complex linear dielectric response, which incorporates both the dielectric constant ε(ω) and the conductivity σ (ω) of the medium.…”