Read by QxMD icon Read


Ida Friis, Emil Sjulstok, Ilia A Solov'yov
Birds use the magnetic field of the Earth to navigate during their annual migratory travel. The possible mechanism to explain the biophysics of this compass sense involves electron transfers within the photoreceptive protein cryptochrome. The magnetoreceptive functioning of cryptochromes is supposedly facilitated through an iron rich polymer complex which couples to multiple cryptochromes. The present investigation aims to independently reconstruct this complex and describe its interaction with Drosophila melanogaster cryptochromes...
October 24, 2017: Scientific Reports
Jing-Jing Xu, Ying-Chao Zhang, Jian-Qi Wu, Wei-Hong Wang, Yue Li, Gui-Jun Wan, Fa-Jun Chen, Gregory A Sword, Wei-Dong Pan
The mechanisms of magnetoreception have been proposed as the magnetite-based, the chemical radical-pair & biocompass model, in which magnetite particles, the cryptochrome (Cry) or iron-sulfur cluster assembly 1 (IscA1) may be involved. However, little is known about the association among the molecules. Here we investigated the molecular characterization and the mRNA expression of IscA1 in different developmental stages, tissues and magnetic fields in the migratory insect of brown planthoppers (BPH), Nilaparvata lugens...
October 23, 2017: Insect Science
Gregory C Nordmann, Tobias Hochstoeger, David A Keays
Evolution has equipped life on our planet with an array of extraordinary senses, but perhaps the least understood is magnetoreception. Despite compelling behavioral evidence that this sense exists, the cells, molecules, and mechanisms that mediate sensory transduction remain unknown. So how could animals detect magnetic fields? We introduce and discuss 3 concepts that attempt to address this question: (1) a mechanically sensitive magnetite-based magnetoreceptor, (2) a light-sensitive chemical-based mechanism, and (3) electromagnetic induction within accessory structures...
October 2017: PLoS Biology
Min Jiang, Lujia Zhang, Fengqing Wang, Jie Zhang, Guosong Liu, Bei Gao, Dongzhi Wei
Recently, a magnetic protein was discovered, and a multimeric magnetosensing complex was validated, which may form the basis of magnetoreception. In this study, the magnetic protein was firstly used in biotechnology application, and a novel convenient one-step purification and immobilization method was established. A universal vector and three linker patterns were developed for fusion expression of magnetic protein and target protein. The magnetic protein was absorbed by iron beads, followed by target protein aggregation, purification, and immobilization...
October 17, 2017: Scientific Reports
Daniel R Kattnig
Birds and several other species are equipped with the remarkable ability to sense the geomagnetic field for the purpose of navigation and orientation. The primary detection mechanism of this compass sense is uncertain but appears to originate from a truly quantum process involving spin-correlated radical pairs. In order to elicit sensitivity to weak magnetic fields, such as the Earth's magnetic field, the underlying spin dynamics must be protected from fast decoherence. In this work, we elucidate the effects of spin relaxation on a recently suggested reaction scheme involving three radicals, instead of a radical pair, doublet-quartet interconversion under magnetic interactions, and a spin-selective scavenging reaction...
October 26, 2017: Journal of Physical Chemistry. B
Kwon-Seok Chae, Yong-Hwan Kim
Throughout the long history of various therapeutic trials of transcranial magnetic stimulation (TMS), some TMS protocols have been reported to be clearly effective in the treatment of neurodegenerative diseases. Despite promising results from repetitive TMS (rTMS) using low frequency electromagnetic fields (EMFs) for neurodegenerative diseases, the low reproducibility has hampered the clinical applications of rTMS. Here, based on the notion of radical pair mechanism explaining magnetoreception in living organisms, we propose a new perspective that rTMS with controlled geomagnetic field (rTMS-GMF) can be an efficient and reproducible therapeutic approach for neurodegenerative diseases...
2017: Frontiers in Human Neuroscience
Hamish G Hiscock, Henrik Mouritsen, David E Manolopoulos, P J Hore
The radical-pair mechanism has been put forward as the basis of the magnetic compass sense of migratory birds. Some of the strongest supporting evidence has come from behavioral experiments in which birds exposed to weak time-dependent magnetic fields lose their ability to orient in the geomagnetic field. However, conflicting results and skepticism about the requirement for abnormally long quantum coherence lifetimes have cast a shroud of uncertainty over these potentially pivotal studies. Using a recently developed computational approach, we explore the effects of various radiofrequency magnetic fields on biologically plausible radicals within the theoretical framework of radical-pair magnetoreception...
October 3, 2017: Biophysical Journal
Shubhajit Paul, Alexey S Kiryutin, Jinping Guo, Konstantin L Ivanov, Jörg Matysik, Alexandra V Yurkovskaya, Xiaojie Wang
Many animals sense the Earth's magnetic-field and use it for navigation. It is proposed that a light-dependent quantum effect in cryptochrome proteins, residing in the retina, allows for such an iron-free spin-chemical compass. The photochemical processes, spin-dynamics and its magnetic field dependence in natural cryptochrome are not fully understood by the in vivo and in vitro studies. For a deeper insight into these biophysical mechanisms in cryptochrome, we had introduced a flavin-tryptophan dyad (F10T)...
September 19, 2017: Scientific Reports
Susannah Worster, Henrik Mouritsen, P J Hore
Billions of migratory birds navigate thousands of kilometres every year aided by a magnetic compass sense, the biophysical mechanism of which is unclear. One leading hypothesis is that absorption of light by specialized photoreceptors in the retina produces short-lived chemical intermediates known as radical pairs whose chemistry is sensitive to tiny magnetic interactions. A potentially serious but largely ignored obstacle to this theory is how directional information derived from the Earth's magnetic field can be separated from the much stronger variations in the intensity and polarization of the incident light...
September 2017: Journal of the Royal Society, Interface
Alexander Pakhomov, Julia Bojarinova, Roman Cherbunin, Raisa Chetverikova, Philipp S Grigoryev, Kirill Kavokin, Dmitry Kobylkov, Regina Lubkovskaja, Nikita Chernetsov
Previously, it has been shown that long-distance migrants, garden warblers (Sylvia borin), were disoriented in the presence of narrow-band oscillating magnetic field (1.403 MHz OMF, 190 nT) during autumn migration. This agrees with the data of previous experiments with European robins (Erithacus rubecula). In this study, we report the results of experiments with garden warblers tested under a 1.403 MHz OMF with various amplitudes (∼0.4, 1, ∼2.4, 7 and 20 nT). We found that the ability of garden warblers to orient in round arenas using the magnetic compass could be disrupted by a very weak oscillating field, such as an approximate 2...
August 2017: Journal of the Royal Society, Interface
Li-Sha Guo, Bao-Ming Xu, Jian Zou, Bin Shao
The radical pair (RP) based compass is considered as one of the principal models of avian magnetoreception. Different from the conventional approach where the sensitivity of RP based compass is described by the singlet yield, we introduce the quantum Fisher information (QFI), which represents the maximum information about the magnetic field's direction extracted from the RP state, to quantify the sensitivity of RP based compass. The consistency between our results and experimental observations suggests that the QFI may serve as a measure to describe the sensitivity of RP based compass...
July 19, 2017: Scientific Reports
Yongjian Li, Taishan Wang, Chong Zhao, Yu Qin, Haibing Meng, Mingzhe Nie, Li Jiang, Chunru Wang
Endohedral lanthanide metallofullerene molecules exhibit various paramagnetic properties. In this study, we present a magnetoreception probe that can detect the magnetic properties of an endohedral metallofullerene via spin-paramagnet interaction between a nitroxide radical and Dy3N@C80. A cycloaddition reaction on the outer cage of Dy3N@C80 was employed to obtain two regioisomers linked with the nitroxide radical; the resultant adduct exhibits site-dependent signal intensity in the ESR spectra. This Dy3N@C80-nitroxide radical adduct has potential applications as a molecular compass with position-sensitive magnetoreception ability...
July 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
Vladimir N Binhi, Frank S Prato
During interplanetary flights in the near future, a human organism will be exposed to prolonged periods of a hypomagnetic field that is 10,000 times weaker than that of Earth's. Attenuation of the geomagnetic field occurs in buildings with steel walls and in buildings with steel reinforcement. It cannot be ruled out also that a zero magnetic field might be interesting in biomedical studies and therapy. Further research in the area of hypomagnetic field effects, as shown in this article, is capable of shedding light on a fundamental problem in biophysics-the problem of primary magnetoreception...
2017: PloS One
Daniel Nohr, Bernd Paulus, Ryan Rodriguez, Asako Okafuji, Robert Bittl, Erik Schleicher, Stefan Weber
Light-generated short-lived radial pairs have been suggested to play pivotal roles in cryptochromes and photolyases. Chryptochromes are very probably involved in magnetic compass sensing in migratory birds and the magnetic-field-dependent behavior of insects. We examined photo-generated transient states in the cryptochrome of Drosophila melanogaster and in the structurally related DNA-repair enzyme Escherichia coli DNA photolyase. Using pulsed EPR spectroscopy, the exchange and dipolar contributions to the electron spin-spin interaction were determined in a straightforward and direct way...
June 19, 2017: Angewandte Chemie
Vishvendra Singh Poonia, Kiran Kondabagil, Dipankar Saha, Swaroop Ganguly
The functional window is an experimentally observed property of the avian compass that refers to its selectivity around the geomagnetic-field strength. We show that the simple radical-pair model, using biologically feasible hyperfine parameters, can qualitatively explain the salient features of the avian compass as observed in behavioral experiments: its functional window, as well as disruption of the compass action by radio-frequency fields of specific frequencies. Further, we show that adjustment of the hyperfine parameters can tune the functional window, suggesting a possible mechanism for its observed adaptation to field variation...
May 2017: Physical Review. E
Christine Nießner, Michael Winklhofer
The radical-pair hypothesis of magnetoreception has gained a lot of momentum, since the flavoprotein cryptochrome was postulated as a structural candidate to host magnetically sensitive chemical reactions. Here, we first discuss behavioral tests using radio-frequency magnetic fields (0.1-10 MHz) to specifically disturb a radical-pair-based avian magnetic compass sense. While disorienting effects of broadband RF magnetic fields have been replicated independently in two competing labs, the effects of monochromatic RF magnetic fields administered at the electronic Larmor frequency (~1...
July 2017: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
Milena Damulewicz, Gabriella M Mazzotta, Elena Sartori, Ezio Rosato, Rodolfo Costa, Elzbieta M Pyza
Drosophila CRYPTOCHROME (CRY) is a blue light sensitive protein with a key role in circadian photoreception. A main feature of CRY is that light promotes an interaction with the circadian protein TIMELESS (TIM) resulting in their ubiquitination and degradation, a mechanism that contributes to the synchronization of the circadian clock to the environment. Moreover, CRY participates in non-circadian functions such as magnetoreception, modulation of neuronal firing, phototransduction and regulation of synaptic plasticity...
2017: Frontiers in Molecular Neuroscience
Eliane Wajnberg, André Linhares Rossi, Darci Motta S Esquivel
The most accepted hypothesis of magnetoreception for social insects is the ferromagnetic hypothesis which assumes the presence of magnetic material as a sensor coupled to sensitive structures that transmit the geomagnetic field information to the nervous system. As magnetite is the most common magnetic material observed in living beings, it has been suggested as basic constituent of the magnetoreception system. Antennae and head have been pointed as possible magnetosensor organs in social insects as ants, bees and termites...
June 12, 2017: Biometals: An International Journal on the Role of Metal Ions in Biology, Biochemistry, and Medicine
Wei Lin, Yongxin Pan, Dennis A Bazylinski
Magnetotactic bacteria (MTB) biomineralize intracellular, membrane-bounded crystals of magnetite (Fe3 O4 ) and/or greigite (Fe3 S4 ) called magnetosomes. MTB play important roles in the geochemical cycling of iron, sulfur, nitrogen and carbon. Significantly, they also represent an intriguing model system not just for the study of microbial biomineralization but also for magnetoreception, prokaryotic organelle formation and microbial biogeography. Here we review current knowledge on the ecology of and biomineralization by MTB, with an emphasis on more recent reports of unexpected ecological and phylogenetic findings regarding MTB...
May 30, 2017: Environmental Microbiology Reports
Brian K Taylor, Sönke Johnsen, Kenneth J Lohmann
Diverse taxa use Earth's magnetic field to aid both short- and long-distance navigation. Study of these behaviors has led to a variety of postulated sensory and processing mechanisms that remain unconfirmed. Although several models have been proposed to explain and understand these mechanisms' underpinnings, they have not necessarily connected a putative sensory signal to the nervous system. Using mathematical software simulation, hardware testing and the computational neuroscience tool of dynamic neural fields, the present work implements a previously developed conceptual model for processing magnetite-based magnetosensory data...
May 19, 2017: Bioinspiration & Biomimetics
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"