ON THE NONLINEAR DIELECTRIC-PROPERTIES OF BIOLOGICAL-SYSTEMS SACCHAROMYCES-CEREVISIAE

The construction of a dual-cell, non-linear dielectric spectrometer is described. The system is applied to the study of resting cell suspensions of S. cerevisiae. Substantial harmonics are generated by these cells when stimulated by very modest exciting fields (ca. ± 2 V cm-1, 20 Hz). The generation of these harmonics occurs only in living cells, and in a cell concentration-dependent manner. We studied the 3rd harmonic in detail. The ability to generate this harmonic is observable only within rather narrow voltage and frequency windows. The generation of a third harmonic is strongly inhibited by low concentrations of sodium metavanadate, suggesting that it may be ascribed largely to the H+-ATPase present in the plasma membranes of these cells. When the enzyme is not at static head, the 3rd harmonic disappears and strong second and 4th harmonics may be observed. Non-linear dielectric spectroscopy constitutes a powerful and convenient means by which to monitor the ability of living cells to transduce exogenous electric field energy. This type of transduction may serve to account for the many reports of the ability of very weak electromagnetic fields to affect biological activity. © 1990.