Parallel arrays of microtubles formed in electric and magnetic fields

Vassilev, Peter; Dronzine, Reni T.; Vassileva, María P.; Georgiev, Georgi

doi:10.1007/bf01122171

Cited by 88 publications

(54 citation statements)

References 8 publications

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“…Here should be noted that the widely quoted "sensitivity" of microtubules to external electric and magnetic fields is indeed (1) arrangement along the field strength lines of the microtubules (Vassilev et al, 1982), (2) The conclusion from the presented data is that before starting microtubule quantum modeling it is useful to be acquainted with the specific intracellular microenvironment. The local electric field in the brain cortex is the carrier of information to our mind (Dobelle, 2000), that's why if microtubules are linked to the cognitive processes in brain their interaction with the electric field is crucial and must be taken into account in the future models.…”

Section: Discussionmentioning

confidence: 93%

Electric and Magnetic Fields Inside Neurons and Their Impact Upon the Cytoskeletal Microtubules

Georgiev

2003

SSRN Journal

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If we want to better understand how the microtubules can translate and input the information carried by the electrophysiologic impulses that enter the brain cortex, a detailed investigation of the local electromagnetic field structure is needed. In this paper are assessed the electric and the magnetic field strengths in different neuronal compartments. The calculated results are verified via experimental data comparison. It is shown that the magnetic field is too weak to input information to microtubules and no Hall effect, respectively QHE is realistic. Local magnetic flux density is less than 1 /300 of the Earth's magnetic field that's why any magnetic signal will be suffocated by the surrounding noise. In contrast the electric field carries biologically important information and acts upon voltage-gated transmembrane ion channels that control the neuronal action potential. If mind is linked to subneuronal processing of information in the brain microtubules then microtubule interaction with the local electric field, as input source of information is crucial. The intensity of the electric field is estimated to be 10V/m inside the neuronal cytoplasm however the details of the tubulin-electric field interaction are still unknown. A novel hypothesis stressing on the tubulin C-termini intraneuronal function is presented replacing the current flawed models (Tuszynski 2003, Mershin 2003, Porter 2003 The electric currents are relevant stimuli eliciting conscious experience like memorization of past events (Wilder Penfield, 1954a;1954b;1955) (2000) has helped a blind man to see again using electrodes implanted into his brain and connected to a tiny television camera mounted on a pair of glasses. Although he does not "see" in the conventional sense, he can make out the outlines of objects, large letters and numbers on a contrasting background, and can use the direct digital input to operate a computer. The man, identified only as Jerry, has been blind since age 36 after a blow to the head. Now 64, he volunteered for the study and got a brain implant in 1978. There has been no infection or rejection in the past 24 years. 7Scientists have been working since 1978 to develop and improve the software that enables Jerry to use the device as a primitive visual system. Jerry's "eye" consists of a tiny television camera and an ultrasonic distance sensor mounted on a pair of eyeglasses. Both devices communicate with a small computer, carried on his hip, which highlights the edges between light and dark areas in the camera image. It then tells an adjacent computer to send appropriate signals to an array of 68 small platinum electrodes on the surface of Jerry's brain, through wires entering his skull behind his right ear. The electrodes stimulate certain brain cells, making Jerry perceive dots of light, which are known as phosphenes.Jerry gets white phosphenes on a black background. With small numbers of phosphenes you have (the equivalent of) a time and temperature sign at a bank.As you get larger and larger numbers of phosphenes...

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Section: Discussionmentioning

confidence: 93%

Electric and Magnetic Fields Inside Neurons and Their Impact Upon the Cytoskeletal Microtubules

Georgiev

2003

SSRN Journal

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“…Pigment granules have paramagnetic centers [Cope et al, 1963] and a negative electric charge [Testorf et al, 2000]. Reorientation of microtubules due to their diamagnetic anisotropy has been reported [Vassilev et al, 1982;Bras et al, 1998]. We were interested in following induced melanophore aggregation (pigment movement along microtubules to the cell center) during exposure to strong homogenous static magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

Melanophore aggregation in strong static magnetic fields

Testorf

Öberg

Iwasaka

et al. 2002

Bioelectromagnetics

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Contradicting results can be found in the literature on effects from magnetic exposure to pigment cells. We have studied the influence of strong, static, homogenous magnetic fields of 8 and 14 T on melanophore aggregation during exposure to the field. Melanophores, black pigment cells, in fish are large flat cells having intracellular black pigment granules. Due to large size, high optical contrast, and quick response to drugs, melanophores are attractive as biosensors as well as for model studies of intracellular processes. This is especially true for modeling nerve cells, since melanophores share stem cells with axons. Twenty experiments on black tetra fish fins were carried out in the two magnetic flux densities. The same number of control experiments were carried out in the magnet with the magnetic field turned off. Several factors, such as the degree of maximal aggregation, speed of aggregation, and irregularity of the speed, were examined. The statistical analysis showed no significant field effects on the aggregation, with one exception: the irregularity in aggregation speed in the 8 T field, compared to control. The believed reorientation of the cytoskeleton (microtubules) in the field or the induced Lorentz force on moving pigment granules, did not affect the aggregation.

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“…The increase of diagonally aligned immobile cells might be caused by the active swimming of the cells and/or by the helical arrangement (Storch and Welsch, 2002) of the microtubules in the pellicle of Euglena. Isolated microtubules orient in parallel with respect to a magnetic field (Vassilev et al, 1982); thus, their helical arrangement in Euglena makes the diagonal orientation of the chloroplastfree cells likely. Due to our observations, we can assume that in the case of chloroplast-bearing cells the anisotropy of the chloroplast rather than that of the microtubules determines the orientation.…”

Section: Reason For Alignmentmentioning

confidence: 99%

Impact of a High Magnetic Field on the Orientation of Gravitactic Unicellular Organisms—A Critical Consideration about the Application of Magnetic Fields to Mimic Functional Weightlessness

Hemmersbach

Simon²,

Waßer³

et al. 2014

Astrobiology

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The gravity-dependent behavior of Paramecium biaurelia and Euglena gracilis have previously been studied on ground and in real microgravity. To validate whether high magnetic field exposure indeed provides a groundbased facility to mimic functional weightlessness, as has been suggested earlier, both cell types were observed during exposure in a strong homogeneous magnetic field (up to 30 T) and a strong magnetic field gradient. While swimming, Paramecium cells were aligned along the magnetic field lines; orientation of Euglena was perpendicular, demonstrating that the magnetic field determines the orientation and thus prevents the organisms from the random swimming known to occur in real microgravity. Exposing Astasia longa, a flagellate that is closely related to Euglena but lacks chloroplasts and the photoreceptor, as well as the chloroplast-free mutant E. gracilis 1F, to a high magnetic field revealed no reorientation to the perpendicular direction as in the case of wild-type E. gracilis, indicating the existence of an anisotropic structure (chloroplasts) that determines the direction of passive orientation. Immobilized Euglena and Paramecium cells could not be levitated even in the highest available magnetic field gradient as sedimentation persisted with little impact of the field on the sedimentation velocities. We conclude that magnetic fields are not suited as a microgravity simulation for gravitactic unicellular organisms due to the strong effect of the magnetic field itself, which masks the effects known from experiments in real microgravity.

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Parallel arrays of microtubles formed in electric and magnetic fields

Cited by 88 publications

References 8 publications

Electric and Magnetic Fields Inside Neurons and Their Impact Upon the Cytoskeletal Microtubules

Electric and Magnetic Fields Inside Neurons and Their Impact Upon the Cytoskeletal Microtubules

Melanophore aggregation in strong static magnetic fields

Impact of a High Magnetic Field on the Orientation of Gravitactic Unicellular Organisms—A Critical Consideration about the Application of Magnetic Fields to Mimic Functional Weightlessness

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