Read by QxMD icon Read


Kirill Kavokin
While many properties of the magnetic compass of migratory birds are satisfactory explained within the chemical model of magnetoreception, its extreme sensitivity to radio-frequency magnetic fields remains a mystery. Apparently, this difficulty could be overcome if the magnetoreceptor model were augmented with a magnetite nanoparticle, which would amplify the magnetic field at the position of the magneto-sensitive cryptochrome molecule. However, comparison of the radio-frequency power used in the experiment with intrinsic magnetization noise of such a particle, estimated from the theory of fluctuations, shows that the required sensitivity cannot be reached with realistic parameters of iron-oxide nanocrystals...
2017: PloS One
Frank S Prato, Vladimir N Binhi
No abstract text is available yet for this article.
March 6, 2017: Bioelectromagnetics
Francisco J Diego-Rasilla, Valentín Pérez-Mellado, Ana Pérez-Cembranos
Several species of vertebrates exhibit spontaneous longitudinal body axis alignment relative to the Earth's magnetic field (i.e., magnetic alignment) while they are performing different behavioural tasks. Since magnetoreception is still not fully understood, studying magnetic alignment provides evidence for magnetoreception and broadens current knowledge of magnetic sense in animals. Furthermore, magnetic alignment widens the roles of magnetic sensitivity in animals and may contribute to shed new light on magnetoreception...
April 2017: Die Naturwissenschaften
Frank Barnes, Ben Greenebaum
No abstract text is available yet for this article.
February 21, 2017: Bioelectromagnetics
Dean M W Sheppard, Jing Li, Kevin B Henbest, Simon R T Neil, Kiminori Maeda, Jonathan Storey, Erik Schleicher, Till Biskup, Ryan Rodriguez, Stefan Weber, P J Hore, Christiane R Timmel, Stuart R Mackenzie
Drosophila have been used as model organisms to explore both the biophysical mechanisms of animal magnetoreception and the possibility that weak, low-frequency anthropogenic electromagnetic fields may have biological consequences. In both cases, the presumed receptor is cryptochrome, a protein thought to be responsible for magnetic compass sensing in migratory birds and a variety of magnetic behavioural responses in insects. Here, we demonstrate that photo-induced electron transfer reactions in Drosophila melanogaster cryptochrome are indeed influenced by magnetic fields of a few millitesla...
February 8, 2017: Scientific Reports
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...
January 2017: Bioelectromagnetics
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
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
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
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
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...
December 2016: Science China. Life Sciences
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
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
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
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
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
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
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...
April 11, 2016: Scientific Reports
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
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
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"