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Magnetoreception

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https://www.readbyqxmd.com/read/27859403/a-physical-mechanism-of-magnetoreception-extension-and-analysis
#1
Vladimir N Binhi, Frank S Prato
Proposed is a general physical mechanism of magnetoreception of weak magnetic fields (MFs). The mechanism is based on classical precessional dynamics of a magnetic moment in a thermally disturbed environment and includes a minimum of necessary parameters-the gyromagnetic ratio, thermal relaxation time, and rate of downstream events generated by changes in the state of the magnetic moment. The mechanism imposes general restrictions on the probability of initial biophysical magnetic transduction event before the involvement of specific biophysical and biochemical mechanisms-i...
November 8, 2016: Bioelectromagnetics
https://www.readbyqxmd.com/read/27858334/identification-of-medaka-magnetoreceptor-and-cryptochromes
#2
Yunzhi Wang, Jianbin Chen, Feng Zhu, Yunhan Hong
Magnetoreception is a hallmark ability of animals for orientation and migration via sensing and utilizing geomagnetic fields. Magnetoreceptor (MagR) and cryptochromes (Cry) have recently been identified as the basis for magnetoreception in Drosophila. However, it has remained unknown whether MagR and Cry have conserved roles in diverse animals. Here we report the identification and expression of magr and cry genes in the fish medaka (Oryzias latipes). Cloning and sequencing identified a single magr gene, four cry genes and one cry-like gene in medaka...
November 17, 2016: Science China. Life Sciences
https://www.readbyqxmd.com/read/27830725/multiscale-description-of-avian-migration-from-chemical-compass-to-behaviour-modeling
#3
J Boiden Pedersen, Claus Nielsen, Ilia A Solov'yov
Despite decades of research the puzzle of the magnetic sense of migratory songbirds has still not been unveiled. Although the problem really needs a multiscale description, most of the individual research efforts were focused on single scale investigations. Here we seek to establish a multiscale link between some of the scales involved, and in particular construct a bridge between electron spin dynamics and migratory bird behaviour. In order to do that, we first consider a model cyclic reaction scheme that could form the basis of the avian magnetic compass...
November 10, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27798129/magnetic-fields-modulate-blue-light-dependent-regulation-of-neuronal-firing-by-cryptochrome
#4
Carlo N G Giachello, Nigel S Scrutton, Alex R Jones, Richard A Baines
: Many animals are able to sense the Earth's geomagnetic field to enable behaviors such as migration. It is proposed that the magnitude and direction of the geomagnetic field modulates the activity of cryptochrome (CRY) by influencing photochemical radical pair intermediates within the protein. However, this proposal will remain theoretical until a CRY-dependent effect on a receptor neuron is shown to be modified by an external magnetic field (MF). It is established that blue-light (BL) photoactivation of CRY is sufficient to depolarize and activate Drosophila neurons...
October 19, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/27780072/sensory-matched-filters
#5
Eric J Warrant
As animals move through their environments they are subjected to an endless barrage of sensory signals. Of these, some will be of utmost importance, such as the tell-tale aroma of a potential mate, the distinctive appearance of a vital food source or the unmistakable sound of an approaching predator. Others will be less important. Indeed some will not be important at all. There are, for instance, wide realms of the sensory world that remain entirely undetected, simply because an animal lacks the physiological capacity to detect and analyse the signals that characterise this realm...
October 24, 2016: Current Biology: CB
https://www.readbyqxmd.com/read/27614751/identification-of-zebrafish-magnetoreceptor-and-cryptochrome-homologs
#6
Zuoqiong Zhou, Xiyang Peng, Jianbin Chen, Xiushan Wu, Yuequn Wang, Yunhan Hong
Magnetoreception is essential for magnetic orientation in animal migration. The molecular basis for magnetoreception has recently been elucidated in fruitfly as complexes between the magnetic receptor magnetoreceptor (MagR) and its ligand cryptochrome (Cry). MagR and Cry are present in the animal kingdom. However, it is unknown whether they perform a conserved role in diverse animals. Here we report the identification and expression of zebrafish MagR and Cry homologs towards understanding their roles in lower vertebrates...
September 6, 2016: Science China. Life Sciences
https://www.readbyqxmd.com/read/27524094/magnetotactic-bacteria-and-magnetosomes-scope-and-challenges
#7
REVIEW
Jobin John Jacob, K Suthindhiran
Geomagnetism aided navigation has been demonstrated by certain organisms which allows them to identify a particular location using magnetic field. This attractive technique to recognize the course was earlier exhibited in numerous animals, for example, birds, insects, reptiles, fishes and mammals. Magnetotactic bacteria (MTB) are one of the best examples for magnetoreception among microorganisms as the magnetic mineral functions as an internal magnet and aid the microbe to move towards the water columns in an oxic-anoxic interface (OAI)...
November 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/27463133/extended-electron-transfer-in-animal-cryptochromes-mediated-by-a-tetrad-of-aromatic-amino-acids
#8
Daniel Nohr, Sophie Franz, Ryan Rodriguez, Bernd Paulus, Lars-Oliver Essen, Stefan Weber, Erik Schleicher
The cryptochrome/photolyase protein family possesses a conserved triad of tryptophans that may act as a molecular wire to transport electrons from the protein surface to the FAD cofactor for activation and/or signaling-state formation. Members from the animal (and animal-like) cryptochrome subclade use this process in a light-induced fashion in a number of exciting responses, such as the (re-)setting of circadian rhythms or magnetoreception; however, electron-transfer pathways have not been explored in detail yet...
July 26, 2016: Biophysical Journal
https://www.readbyqxmd.com/read/27448908/spin-relaxation-of-radicals-in-cryptochrome-and-its-role-in-avian-magnetoreception
#9
Susannah Worster, Daniel R Kattnig, P J Hore
Long-lived spin coherence and rotationally ordered radical pairs have previously been identified as key requirements for the radical pair mechanism of the avian magnetic compass sense. Both criteria are hard to meet in a biological environment, where thermal motion of the radicals creates dynamic disorder and drives efficient spin relaxation. This has long been cited as a major stumbling block of the radical pair hypothesis. Here we combine Redfield relaxation theory with analytical solutions to a rotational diffusion equation to assess the impact of restricted rotational motion of the radicals on the operation of the compass...
July 21, 2016: Journal of Chemical Physics
https://www.readbyqxmd.com/read/27216936/the-radical-pair-mechanism-of-magnetoreception
#10
P J Hore, Henrik Mouritsen
Although it has been known for almost half a century that migratory birds can detect the direction of the Earth's magnetic field, the primary sensory mechanism behind this remarkable feat is still unclear. The leading hypothesis centers on radical pairs-magnetically sensitive chemical intermediates formed by photoexcitation of cryptochrome proteins in the retina. Our primary aim here is to explain the chemical and physical aspects of the radical-pair mechanism to biologists and the biological and chemical aspects to physicists...
July 5, 2016: Annual Review of Biophysics
https://www.readbyqxmd.com/read/27195955/magnetoreception-regulates-male-courtship-activity-in-drosophila
#11
Chia-Lin Wu, Tsai-Feng Fu, Meng-Hsuan Chiang, Yu-Wei Chang, Jim-Long Her, Tony Wu
The possible neurological and biophysical effects of magnetic fields on animals is an area of active study. Here, we report that courtship activity of male Drosophila increases in a magnetic field and that this effect is regulated by the blue light-dependent photoreceptor cryptochrome (CRY). Naïve male flies exhibited significantly increased courtship activities when they were exposed to a ≥ 20-Gauss static magnetic field, compared with their behavior in the natural environment (0 Gauss). CRY-deficient flies, cryb and crym, did not show an increased courtship index in a magnetic field...
2016: PloS One
https://www.readbyqxmd.com/read/27146685/light-dependent-magnetoreception-in-birds-the-crucial-step-occurs-in-the-dark
#12
Roswitha Wiltschko, Margaret Ahmad, Christine Nießner, Dennis Gehring, Wolfgang Wiltschko
The Radical Pair Model proposes that the avian magnetic compass is based on spin-chemical processes: since the ratio between the two spin states singlet and triplet of radical pairs depends on their alignment in the magnetic field, it can provide information on magnetic directions. Cryptochromes, blue light-absorbing flavoproteins, with flavin adenine dinucleotide as chromophore, are suggested as molecules forming the radical pairs underlying magnetoreception. When activated by light, cryptochromes undergo a redox cycle, in the course of which radical pairs are generated during photo-reduction as well as during light-independent re-oxidation...
May 2016: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/27063288/high-magnetic-field-induced-otolith-fusion-in-the-zebrafish-larvae
#13
Patricia Pais-Roldán, Ajeet Pratap Singh, Hildegard Schulz, Xin Yu
Magnetoreception in animals illustrates the interaction of biological systems with the geomagnetic field (geoMF). However, there are few studies that identified the impact of high magnetic field (MF) exposure from Magnetic Resonance Imaging (MRI) scanners (>100,000 times of geoMF) on specific biological targets. Here, we investigated the effects of a 14 Tesla MRI scanner on zebrafish larvae. All zebrafish larvae aligned parallel to the B0 field, i.e. the static MF, in the MRI scanner. The two otoliths (ear stones) in the otic vesicles of zebrafish larvae older than 24 hours post fertilization (hpf) fused together after the high MF exposure as short as 2 hours, yielding a single-otolith phenotype with aberrant swimming behavior...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27059891/shifted-magnetic-alignment-in-vertebrates-evidence-for-neural-lateralization
#14
E Pascal Malkemper, Michael S Painter, Lukas Landler
A wealth of evidence provides support for magnetic alignment (MA) behavior in a variety of disparate species within the animal kingdom, in which an animal, or a group of animals, show a tendency to align the body axis in a consistent orientation relative to the geomagnetic field lines. Interestingly, among vertebrates, MA typically coincides with the north-south magnetic axis, however, the mean directional preferences of an individual or group of organisms is often rotated clockwise from the north-south axis...
June 21, 2016: Journal of Theoretical Biology
https://www.readbyqxmd.com/read/27045095/effect-of-magnetic-pulses-on-caribbean-spiny-lobsters-implications-for-magnetoreception
#15
David A Ernst, Kenneth J Lohmann
The Caribbean spiny lobster, Panulirus argus, is a migratory crustacean that uses Earth's magnetic field as a navigational cue, but how these lobsters detect magnetic fields is not known. Magnetic material thought to be magnetite has previously been detected in spiny lobsters, but its role in magnetoreception, if any, remains unclear. As a first step toward investigating whether lobsters might have magnetite-based magnetoreceptors, we subjected lobsters to strong, pulsed magnetic fields capable of reversing the magnetic dipole moment of biogenic magnetite crystals...
June 15, 2016: Journal of Experimental Biology
https://www.readbyqxmd.com/read/27044102/the-quantum-needle-of-the-avian-magnetic-compass
#16
Hamish G Hiscock, Susannah Worster, Daniel R Kattnig, Charlotte Steers, Ye Jin, David E Manolopoulos, Henrik Mouritsen, P J Hore
Migratory birds have a light-dependent magnetic compass, the mechanism of which is thought to involve radical pairs formed photochemically in cryptochrome proteins in the retina. Theoretical descriptions of this compass have thus far been unable to account for the high precision with which birds are able to detect the direction of the Earth's magnetic field. Here we use coherent spin dynamics simulations to explore the behavior of realistic models of cryptochrome-based radical pairs. We show that when the spin coherence persists for longer than a few microseconds, the output of the sensor contains a sharp feature, referred to as a spike...
April 26, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27026715/the-magnetic-orientation-of-the-antarctic-amphipod-gondogeneia-antarctica-is-cancelled-by-very-weak-radiofrequency-fields
#17
K Tomanova, M Vacha
Studies on weak man-made radiofrequency (RF) electromagnetic fields affecting animal magnetoreception aim for a better understanding of the reception mechanism and also point to a new phenomenon having possible consequences in ecology and environmental protection. RF impacts on magnetic compasses have recently been demonstrated in migratory birds and other vertebrates. We set out to investigate the effect of RF on the magnetic orientation of the Antarctic krill species Gondogeneia antarctica, a small marine crustacean widespread along the Antarctic littoral line...
June 1, 2016: Journal of Experimental Biology
https://www.readbyqxmd.com/read/27020113/electron-spin-relaxation-in-cryptochrome-based-magnetoreception
#18
Daniel R Kattnig, Ilia A Solov'yov, P J Hore
The magnetic compass sense of migratory birds is thought to rely on magnetically sensitive radical pairs formed photochemically in cryptochrome proteins in the retina. An important requirement of this hypothesis is that electron spin relaxation is slow enough for the Earth's magnetic field to have a significant effect on the coherent spin dynamics of the radicals. It is generally assumed that evolutionary pressure has led to protection of the electron spins from irreversible loss of coherence in order that the underlying quantum dynamics can survive in a noisy biological environment...
May 14, 2016: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/27005398/magnetic-sensing-through-the-abdomen-of-the-honey-bee
#19
Chao-Hung Liang, Cheng-Long Chuang, Joe-Air Jiang, En-Cheng Yang
Honey bees have the ability to detect the Earth's magnetic field, and the suspected magnetoreceptors are the iron granules in the abdomens of the bees. To identify the sensing route of honey bee magnetoreception, we conducted a classical conditioning experiment in which the responses of the proboscis extension reflex (PER) were monitored. Honey bees were successfully trained to associate the magnetic stimulus with a sucrose reward after two days of training. When the neural connection of the ventral nerve cord (VNC) between the abdomen and the thorax was cut, the honey bees no longer associated the magnetic stimulus with the sucrose reward but still responded to an olfactory PER task...
2016: Scientific Reports
https://www.readbyqxmd.com/read/27001735/chemical-amplification-of-magnetic-field-effects-relevant-to-avian-magnetoreception
#20
Daniel R Kattnig, Emrys W Evans, Victoire Déjean, Charlotte A Dodson, Mark I Wallace, Stuart R Mackenzie, Christiane R Timmel, P J Hore
Magnetic fields as weak as the Earth's can change the yields of radical pair reactions even though the energies involved are orders of magnitude smaller than the thermal energy, kBT, at room temperature. Proposed as the source of the light-dependent magnetic compass in migratory birds, the radical pair mechanism is thought to operate in cryptochrome flavoproteins in the retina. Here we demonstrate that the primary magnetic field effect on flavin photoreactions can be amplified chemically by slow radical termination reactions under conditions of continuous photoexcitation...
April 2016: Nature Chemistry
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