Harmonic Response of Cellular Membrane Pumps to Low Frequency Electric Fields

Abstract

We report on harmonic generation by budding yeast cells in response to a sinusoidal electric field, which is seen to be minimal when the field amplitude is less than a threshold value. Surprisingly, sodium metavanadate, an inhibitor of P-type ATPases reportedly responsible for nonlinear response in yeast, reduces the threshold field amplitude, increasing harmonic generation at low amplitudes while reducing it at large amplitudes, whereas the addition of glucose dramatically increases the production of even harmonics. Finally, a simple model is proposed to interpret the observed behavior.

Cellular apoptosis by nanosecond, high-intensity electric pulses: Model evaluation of the pulsing threshold and extrinsic pathway

“…For example, the electric pulsing can be expected to trigger and influence a wide number of processes, not limited simply to caspase-8 activation, regulation of the mitochondrial transmembrane potential, or electroporation. These would include, for example, induced electron transfers between molecules leading to possible dissociation or conformational changes, facilitation of oxidation-reduction (redox) reactions and influence on their rate kinetics, alterations of membrane pumps [57], or calcium release from the endoplasmic reticulum [58]. Hence, the primary electrical event could lead to several downstream biochemical modifications, initiation of inter-dependent pathways, and interplay between multiple secondary processes.…”

SQUID-Based Biosensor for Probing Ion Transporters in Cell Suspensions and Tissue

“…The method involves excitation of a biological sample with a sinusoidal electric field (0-5 V/cm, 10-300 Hz), detection, with a SQUID magnetometer, of the magnetic field produced by ac currents in the tissue or cell suspension, and calculation of the Fast Fourier Transform (FFT) of the measured response to obtain a spectrum. We find that the harmonic response of budding yeast cells (S. cerevisiae, 10 8 cells/ml) is sensitive to sodium metavanadate, an inhibitor of a proton pump known as H + -ATPase, glucose, a substrate of H + -ATPase, and gramicidin, a membrane depolarizer. SQUID-based field and frequency dependent harmonic response measurements are also made of a live earthworm (Lumbricus terrestris).…”

Harmonic Analysis of Neuronal Membranes and Tissue Using SQUIDs

“…At low frequencies below , membrane fields across a 10-nm lipid bilayer are induced for each V/cm increase in excitation amplitude. These induced fields Manuscript cause conformation changes in membrane proteins [4] such as -ATPase in S. cerevisiae suspensions [1], [2], [5] resulting in a distorted sinusoidal response signal. Membranous enzymes may also harness electric field energy to perform biological work such as the translocation of ions in an amplitude and frequency dependent way [6] thus giving rise to harmonics.…”