Induction ofFucus egg polarity by electric a.c.-fields

Novak, B.; Bentrup, Friedrich‐Wilhelm

doi:10.1007/bf00625337

Cited by 7 publications

(6 citation statements)

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“…This hypothesis suggests that net asymmetric serotonin movement occurs through gap junctions, is driven by electrophoretic forces generated by ion pump-dependent membrane voltage differences across the ventral midline, and ultimately induces asymmetric downstream genes (Levin, 2004). This class of models has been previously proposed for a number of morphogen systems (Rose, 1966;Novak and Bentrup, 1973;Lange and Steele, 1978;Larter and Ortoleva, 1981) and is compatible with many other small molecule signals. Inositol polyphosphates are also likely candidates, as they have been implicated in asymmetry (Albrieux and Villaz, 2000;Sarmah et al, 2005), as well as being downstream of a voltage sensor (Murata et al, 2005).…”

Section: The Embryo Is An Electrophoresis Chamber: One Model Synthesimentioning

confidence: 87%

Is the early left‐right axis like a plant, a kidney, or a neuron? The integration of physiological signals in embryonic asymmetry

Levin¹

2006

Birth Defects Research Pt C

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Embryonic morphogenesis occurs along three orthogonal axes. While the patterning of the anterior-posterior and dorsal-ventral axes has been increasingly well-characterized, the left-right (LR) axis has only relatively recently begun to be understood at the molecular level. The mechanisms that ensure invariant LR asymmetry of the heart, viscera, and brain involve fundamental aspects of cell biology, biophysics, and evolutionary biology, and are important not only for basic science but also for the biomedicine of a wide range of birth defects and human genetic syndromes. The LR axis links biomolecular chirality to embryonic development and ultimately to behavior and cognition, revealing feedback loops and conserved functional modules occurring as widely as plants and mammals. This review focuses on the unique and fascinating physiological aspects of LR patterning in a number of vertebrate and invertebrate species, discusses several profound mechanistic analogies between biological regulation in diverse systems (specifically proposing a nonciliary parallel between kidney cells and the LR axis based on subcellular regulation of ion transporter targeting), highlights the possible importance of early, highly-conserved intracellular events that are magnified to embryo-wide scales, and lays out the most important open questions about the function, evolutionary origin, and conservation of mechanisms underlying embryonic asymmetry.

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Section: The Embryo Is An Electrophoresis Chamber: One Model Synthesimentioning

confidence: 87%

Is the early left‐right axis like a plant, a kidney, or a neuron? The integration of physiological signals in embryonic asymmetry

Levin¹

2006

Birth Defects Research Pt C

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“…2). We mention, on the other hand, that steady electric fields of only 0.1 to 1 V cm -1 are sensed by such cells, because they effectively orient the morphological polarity when applied during cell development [2,6,13].…”

Section: Discussionmentioning

confidence: 99%

“…Eo is received by the egg membrane only if zv is longer than r.% (pa+0.5pc), with Cm membrane capacitance per cm 2 and Pc cytoplasmic resistivity in f~cm [I7]; that is, using pertinent values for the Fucus egg [13,20], if zv>0.7 gsec. In the present study zp ranged from 0.9 to 1760 gsec (see Fig.…”

Section: The Pulse Discharge Chambermentioning

confidence: 99%

A study of dielectric membrane breakdown in theFucus egg

Gauger

Bentrup

1979

J. Membrain Biol.

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Unfertilized eggs and zygotes of the marine brown alga, Fucus serratus, have been subjected to single external electric field pulses of 1 to 1760 musec duration (tau p) and 50 to 400 V field strength (Upcm-1). During exposure, the difference in electric potential across the plasmalemma (Vm) was recorded intracellularly from single eggs, and the efflux of 86Rb+(K+) from the cytoplasm was measured on egg populations. A given single pulse instantaneously depolarizes the plasmalemma by a few (i.e., 6) millivolts and releases a certain fraction (i.e., 5%) of the cytoplasmic 86Rb+(K+). The dependence of these responses upon Up and tau p is fully consistent with the assumption that the membrane undergoes a localized reversible dielectric breakdown and reseals within less than 3 sec. The data are treated in terms of the electro-mechanical model for a compressible membrane by H.G.L. Coster and U. Zimmermann (1975, J. Membrane Biol. 22:73) and verify this model on a nonvacuolated plant cell. A threshold Vm for membrane breakdown (Vc) of 0.58 and 0.51 V is estimated for the turgorless unfertilized eggs and the turgescent (4.8 bar) zygotes, respectively. Using these values for Vc, and a reasonable value of the membrane's elastic modulus (i.e., Ym approximately 10(6) Nm-2), possible sites of membrane breakdown are discussed in terms of membrane thickness and relative permittivity.

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“…It does, however, indicate that the cells' voltage sensing mechanisms may be more complex than once thought, and are programmable to give responses in either direction. Novák and Bentrup (1973) discovered that the electrical effects on the germination of the Fucus zygote were voltage rather than current dependent when they found that they also occurred in pure electrostatic fields. This suggests that voltage-gated ion channels may be the sensors.…”

Section: Direct Current Effects On Single Cellsmentioning

confidence: 96%

Effects of Electrical and Electromagnetic Fields on Plants and Related Topics

Goldsworthy¹

2006

Plant Electrophysiology

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Anyone reading this book cannot fail to realize the importance of self-generated electric fields and currents in the energetics and control of metabolism in plants. We should therefore not be too surprised to find that externally applied fields also have effects. In this chapter, I will describe a few of the more significant findings from over a century of research and try to explain and sometimes reinterpret them in the light of more modern knowledge. The work is divided into three sections. Section 1 is on the non-polar effects of DC fields, where the effects are not related to the direction of the field. It ranges from responses to massive electric fields, such as those found in thunderstorms, to the effects of much weaker ones on the growth and differentiation of tissue cultures. Section 2 is on the polar effects of DC fields, where the direction of the response is related to the direction of the field and includes effects on polar growth and tropisms. Section 3 is on the effects of time-varying and alternating electromagnetic fields, where I will present evidence that a simple change in membrane stability can account for virtually all of the hitherto mysterious biological effects of weak electromagnetic radiation. Non-polar effects of DC electric fields High voltage natural fields and the rise and fall of electroculture PhenomenologyWork on the effects of electrical fields on plants goes back several centuries, but the first person to carry out large scale experiments was Karl Lemström, who was a Professor of Physics at Helsinki. He had paid several visits to the Arctic, and was surprised how green and healthy the vegetation looked, despite the low light and temperature. He wondered whether this might be due to the weak electric currents carried through the atmosphere by air ions from the aurora borealis. His suspicions were confirmed when he looked at

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Induction ofFucus egg polarity by electric a.c.-fields

Cited by 7 publications

References 1 publication

Is the early left‐right axis like a plant, a kidney, or a neuron? The integration of physiological signals in embryonic asymmetry

Is the early left‐right axis like a plant, a kidney, or a neuron? The integration of physiological signals in embryonic asymmetry

A study of dielectric membrane breakdown in theFucus egg

Effects of Electrical and Electromagnetic Fields on Plants and Related Topics

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