51
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Zadeh-Haghighi H, Simon C. Entangled radicals may explain lithium effects on hyperactivity. Sci Rep 2021; 11:12121. [PMID: 34108537 PMCID: PMC8190433 DOI: 10.1038/s41598-021-91388-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/26/2021] [Indexed: 02/05/2023] Open
Abstract
It is known that bipolar disorder and its lithium treatment involve the modulation of oxidative stress. Moreover, it has been observed that lithium's effects are isotope-dependent. Based on these findings, here we propose that lithium exerts its effects by influencing the recombination dynamics of a naturally occurring radical pair involving oxygen. We develop a simple model inspired by the radical-pair mechanism in cryptochrome in the context of avian magnetoreception and xenon-induced anesthesia. Our model reproduces the observed isotopic dependence in the lithium treatment of hyperactivity in rats. It predicts a magnetic-field dependence of the effectiveness of lithium, which provides one potential experimental test of our hypothesis. Our findings show that Nature might harness quantum entanglement for the brain's cognitive processes.
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Affiliation(s)
- Hadi Zadeh-Haghighi
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Quantum Alberta, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
| | - Christoph Simon
- Department of Physics and Astronomy, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Institute for Quantum Science and Technology, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Quantum Alberta, University of Calgary, Calgary, AB, T2N 1N4, Canada.
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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52
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Low magnetic field effects on a photoinduced electron transfer reaction in an ionic liquid. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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53
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Magnetic sensitivity of cryptochrome 4 from a migratory songbird. Nature 2021; 594:535-540. [PMID: 34163056 DOI: 10.1038/s41586-021-03618-9] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 05/06/2021] [Indexed: 02/06/2023]
Abstract
Night-migratory songbirds are remarkably proficient navigators1. Flying alone and often over great distances, they use various directional cues including, crucially, a light-dependent magnetic compass2,3. The mechanism of this compass has been suggested to rely on the quantum spin dynamics of photoinduced radical pairs in cryptochrome flavoproteins located in the retinas of the birds4-7. Here we show that the photochemistry of cryptochrome 4 (CRY4) from the night-migratory European robin (Erithacus rubecula) is magnetically sensitive in vitro, and more so than CRY4 from two non-migratory bird species, chicken (Gallus gallus) and pigeon (Columba livia). Site-specific mutations of ErCRY4 reveal the roles of four successive flavin-tryptophan radical pairs in generating magnetic field effects and in stabilizing potential signalling states in a way that could enable sensing and signalling functions to be independently optimized in night-migratory birds.
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54
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Karki N, Vergish S, Zoltowski BD. Cryptochromes: Photochemical and structural insight into magnetoreception. Protein Sci 2021; 30:1521-1534. [PMID: 33993574 DOI: 10.1002/pro.4124] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 12/21/2022]
Abstract
Cryptochromes (CRYs) function as blue light photoreceptors in diverse physiological processes in nearly all kingdoms of life. Over the past several decades, they have emerged as the most likely candidates for light-dependent magnetoreception in animals, however, a long history of conflicts between in vitro photochemistry and in vivo behavioral data complicate validation of CRYs as a magnetosensor. In this review, we highlight the origins of conflicts regarding CRY photochemistry and signal transduction, and identify recent data that provides clarity on potential mechanisms of signal transduction in magnetoreception. The review primarily focuses on examining differences in photochemistry and signal transduction in plant and animal CRYs, and identifies potential modes of convergent evolution within these independent lineages that may identify conserved signaling pathways.
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Affiliation(s)
- Nischal Karki
- Department of Chemistry, Southern Methodist University, Dallas, Texas, USA
| | - Satyam Vergish
- Department of Chemistry, Southern Methodist University, Dallas, Texas, USA
| | - Brian D Zoltowski
- Department of Chemistry, Southern Methodist University, Dallas, Texas, USA
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55
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Abstract
We demonstrate, by direct, single-cell imaging kinetic measurements, that endogenous autofluorescence in HeLa cells is sensitive to the application of external magnetic fields of 25 mT and less. We provide spectroscopic and mechanistic evidence that our findings can be explained in terms of magnetic field effects on photoinduced electron transfer reactions to flavins, through the radical pair mechanism. The observed magnetic field dependence is consistent with a triplet-born radical pair and a B1/2 value of 18.0 mT with a saturation value of 3.7%.
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56
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Abstract
Species throughout the animal kingdom use the Earth's magnetic field (MF) to navigate using either or both of two mechanisms. The first relies on magnetite crystals in tissue where their magnetic moments align with the MF to transduce a signal transmitted to the central nervous system. The second and the subject of this paper involves cryptochrome (CRY) proteins located in cone photoreceptors distributed across the retina, studied most extensively in birds. According to the "Radical Pair Mechanism" (RPM), blue/UV light excites CRY's flavin cofactor (FAD) to generate radical pairs whose singlet-to-triplet interconversion rate is modulated by an external MF. The signaling product of the RPM produces an impression of the field across the retinal surface. In birds, the resulting signal on the optic nerve is transmitted along the thalamofugal pathway to the primary visual cortex, which projects to brain regions concerned with image processing, memory, and executive function. The net result is a bird's orientation to the MF's inclination: its vector angle relative to the Earth's surface. The quality of ambient light (e.g., polarization) provides additional input to the compass. In birds, the Type IV CRY isoform appears pivotal to the compass, given its positioning within retinal cones; a cytosolic location therein indicating no role in the circadian clock; relatively steady diurnal levels (unlike Type II CRY's cycling); and a full complement of FAD (essential for photosensitivity). The evidence indicates that mammalian Type II CRY isoforms play a light-independent role in the cellular molecular clock without a photoreceptive function.
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Affiliation(s)
| | - Joseph Brain
- Environmental Physiology, Molecular, and Integrative Physiological Sciences Program, Department of Environmental Health, Harvard T. H. Chan School of Public Health, Boston, Massachusetts
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57
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Oka Y, Miura T, Ikoma T. Photogenerated Radical Pair between Flavin and a Tryptophan-Containing Transmembrane-Type Peptide in a Large Unilamellar Vesicle. J Phys Chem B 2021; 125:4057-4066. [PMID: 33858138 DOI: 10.1021/acs.jpcb.1c01231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electron-transfer (ET) reactions in biological systems, such as those with magnetic sensors based on flavoproteins and electron transport at biomembrane interfaces, are interesting and important issues that require understanding. As a model system of flavoproteins in biomimetic environments, we report the dynamics of the radical pair generated by photoinduced ET between riboflavin tetrabutylate (RFTB) and tryptophan (Trp) residues in a transmembrane-type polypeptide, both of which are distributed in a large unilamellar vesicle of 1,2-dimyristoyl-sn-glycero-3-phosphocholine. The Trp residues locate near the hydrophilic membrane interface, as confirmed by a dual-fluorescence quenching assay. The fluorescence and transient absorption upon photoexcitation of RFTB indicate that ET from both the singlet and triplet excited states occurs at the hydrophilic interface, whereas the RFTB in the hydrophobic region does not contribute to ET. The ET efficiency and the magnetic field effect (MFE) on the RFTB anion increase significantly above the gel-to-liquid crystal phase transition temperature due to a decrease in microviscosity. The MFE analysis indicates that the radical pair generated from the triplet ET channel exhibits a long lifetime as those in micellar systems due to the strong cage effect of the vesicle.
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Affiliation(s)
- Yoshimi Oka
- Frontier Research Core for Life Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan
| | - Tomoaki Miura
- Department of Chemistry, Faculty of Science, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
| | - Tadaaki Ikoma
- Department of Chemistry, Faculty of Science, Niigata University, 2-8050 Ikarashi, Nishi-ku, Niigata 950-2181, Japan
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58
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Smith J, Zadeh Haghighi H, Salahub D, Simon C. Radical pairs may play a role in xenon-induced general anesthesia. Sci Rep 2021; 11:6287. [PMID: 33737599 PMCID: PMC7973516 DOI: 10.1038/s41598-021-85673-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 03/03/2021] [Indexed: 02/06/2023] Open
Abstract
Understanding the mechanisms underlying general anesthesia would be a key step towards understanding consciousness. The process of xenon-induced general anesthesia has been shown to involve electron transfer, and the potency of xenon as a general anesthetic exhibits isotopic dependence. We propose that these observations can be explained by a mechanism in which the xenon nuclear spin influences the recombination dynamics of a naturally occurring radical pair of electrons. We develop a simple model inspired by the body of work on the radical-pair mechanism in cryptochrome in the context of avian magnetoreception, and we show that our model can reproduce the observed isotopic dependence of the general anesthetic potency of xenon in mice. Our results are consistent with the idea that radical pairs of electrons with entangled spins could be important for consciousness.
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Affiliation(s)
- Jordan Smith
- Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
| | - Hadi Zadeh Haghighi
- Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Dennis Salahub
- Department of Chemistry, Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, Centre for Molecular Simulation, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Christoph Simon
- Department of Physics and Astronomy, Institute for Quantum Science and Technology, Quantum Alberta, and Hotchkiss Brain Institute, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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59
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Bolte P, Einwich A, Seth PK, Chetverikova R, Heyers D, Wojahn I, Janssen-Bienhold U, Feederle R, Hore P, Dedek K, Mouritsen H. Cryptochrome 1a localisation in light- and dark-adapted retinae of several migratory and non-migratory bird species: no signs of light-dependent activation. ETHOL ECOL EVOL 2021. [DOI: 10.1080/03949370.2020.1870571] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Petra Bolte
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Angelika Einwich
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Pranav K. Seth
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Raisa Chetverikova
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Dominik Heyers
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
- Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Irina Wojahn
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Ulrike Janssen-Bienhold
- Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
- Department of Neuroscience, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Regina Feederle
- Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany
| | - Peter Hore
- Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Karin Dedek
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
- Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
- Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
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60
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Wan G, Hayden AN, Iiams SE, Merlin C. Cryptochrome 1 mediates light-dependent inclination magnetosensing in monarch butterflies. Nat Commun 2021; 12:771. [PMID: 33536422 PMCID: PMC7859408 DOI: 10.1038/s41467-021-21002-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 01/05/2021] [Indexed: 11/09/2022] Open
Abstract
Many animals use the Earth's geomagnetic field for orientation and navigation. Yet, the molecular and cellular underpinnings of the magnetic sense remain largely unknown. A biophysical model proposed that magnetoreception can be achieved through quantum effects of magnetically-sensitive radical pairs formed by the photoexcitation of cryptochrome (CRY) proteins. Studies in Drosophila are the only ones to date to have provided compelling evidence for the ultraviolet (UV)-A/blue light-sensitive type 1 CRY (CRY1) involvement in animal magnetoreception, and surprisingly extended this discovery to the light-insensitive mammalian-like type 2 CRYs (CRY2s) of both monarchs and humans. Here, we show that monarchs respond to a reversal of the inclination of the Earth's magnetic field in an UV-A/blue light and CRY1, but not CRY2, dependent manner. We further demonstrate that both antennae and eyes, which express CRY1, are magnetosensory organs. Our work argues that only light-sensitive CRYs function in animal light-dependent inclination-based magnetic sensing.
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Affiliation(s)
- Guijun Wan
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA. .,Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
| | - Ashley N Hayden
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA
| | - Samantha E Iiams
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA.,Genetics Interdisciplinary Program, Texas A&M University, College Station, TX, USA
| | - Christine Merlin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA. .,Genetics Interdisciplinary Program, Texas A&M University, College Station, TX, USA.
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61
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Wan GJ, Jiang SL, Zhang M, Zhao JY, Zhang YC, Pan WD, Sword GA, Chen FJ. Geomagnetic field absence reduces adult body weight of a migratory insect by disrupting feeding behavior and appetite regulation. INSECT SCIENCE 2021; 28:251-260. [PMID: 32065478 DOI: 10.1111/1744-7917.12765] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/29/2020] [Accepted: 02/04/2020] [Indexed: 06/10/2023]
Abstract
The geomagnetic field (GMF) is well documented for its essential role as a cue used in animal orientation or navigation. Recent evidence indicates that the absence of GMF (mimicked by the near-zero magnetic field, NZMF) can trigger stress-like responses such as reduced body weight, as we have previously shown in the brown planthopper, Nilaparvata lugens. In this study, we found that consistent with the significantly decreased body weight of newly emerged female (-14.67%) and male (-13.17%) adult N. lugens, the duration of the phloem ingestion feeding waveform was significantly reduced by 32.02% in 5th instar nymphs reared under the NZMF versus GMF. Interestingly, 5th instar nymphs that exhibited reduced feeding had significantly higher glucose levels (+16.98% and +20.05%; 24 h and 48 h after molting), which are associated with food aversion, and expression patterns of their appetite-related neuropeptide genes (neuropeptide F, down-regulated overall; short neuropeptide F, down-regulated overall; adipokinetic hormone, up-regulated overall; and adipokinetic hormone receptor, down-regulated overall) were also altered under the absence of GMF in a manner consistent with diminishing appetite. Moreover, the expressions of the potential magnetosensor cryptochromes (Crys) were found significantly altered under the absence of GMF, indicating the likely upstream signaling of the Cry-mediated magnetoreception mechanisms. These findings support the hypothesis that strong changes in GMF intensity can reduce adult body weight through affecting insect feeding behavior and underlying regulatory processes including appetite regulation. Our results highlight that GMF could be necessary for the maintenance of energy homeostasis in insects.
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Affiliation(s)
- Gui-Jun Wan
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Shou-Lin Jiang
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Ming Zhang
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Jing-Yu Zhao
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Ying-Chao Zhang
- Beijing Key Laboratory of Bioelectromagetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Wei-Dong Pan
- Beijing Key Laboratory of Bioelectromagetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Gregory A Sword
- Department of Entomology, Texas A&M University, College Station, TX, U.S.A
| | - Fa-Jun Chen
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
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62
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Wong SY, Solov'yov IA, Hore PJ, Kattnig DR. Nuclear polarization effects in cryptochrome-based magnetoreception. J Chem Phys 2021; 154:035102. [PMID: 33499614 DOI: 10.1063/5.0038947] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The mechanism of the magnetic compass sense of migratory songbirds is thought to involve magnetically sensitive chemical reactions of light-induced radical pairs in cryptochrome proteins located in the birds' eyes. However, it is not yet clear whether this mechanism would be sensitive enough to form the basis of a viable compass. In the present work, we report spin dynamics simulations of models of cryptochrome-based radical pairs to assess whether accumulation of nuclear spin polarization in multiple photocycles could lead to significant enhancements in the sensitivity with which the proteins respond to the direction of the geomagnetic field. Although buildup of nuclear polarization appears to offer sensitivity advantages in the more idealized model systems studied, we find that these enhancements do not carry over to conditions that more closely resemble the situation thought to exist in vivo. On the basis of these simulations, we conclude that buildup of nuclear polarization seems unlikely to be a source of significant improvements in the performance of cryptochrome-based radical pair magnetoreceptors.
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Affiliation(s)
- Siu Ying Wong
- Institut für Physik, Carl-von-Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany
| | - Ilia A Solov'yov
- Institut für Physik, Carl-von-Ossietzky Universität Oldenburg, 26111 Oldenburg, Germany
| | - P J Hore
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom
| | - Daniel R Kattnig
- Living Systems Institute and Department of Physics, University of Exeter, Exeter EX4 4QD, United Kingdom
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63
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Ren Y, Hiscock HG, Hore PJ. Angular Precision of Radical Pair Compass Magnetoreceptors. Biophys J 2021; 120:547-555. [PMID: 33421412 PMCID: PMC7896030 DOI: 10.1016/j.bpj.2020.12.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/17/2020] [Accepted: 12/30/2020] [Indexed: 11/19/2022] Open
Abstract
The light-dependent magnetic compass sense of night-migratory songbirds is thought to rely on magnetically sensitive chemical reactions of radical pairs in cryptochrome proteins located in the birds' eyes. Recently, an information theory approach was developed that provides a strict lower bound on the precision with which a bird could estimate its head direction using only geomagnetic cues and a cryptochrome-based radical pair sensor. By means of this lower bound, we show here how the performance of the compass sense could be optimized by adjusting the orientation of cryptochrome molecules within photoreceptor cells, the distribution of cells around the retina, and the effects of the geomagnetic field on the photochemistry of the radical pair.
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Affiliation(s)
- Yi Ren
- Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - Hamish G Hiscock
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - P J Hore
- Department of Chemistry, University of Oxford, Oxford, United Kingdom.
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64
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Schwinn K, Ferré N, Huix-Rotllant M. UV-visible absorption spectrum of FAD and its reduced forms embedded in a cryptochrome protein. Phys Chem Chem Phys 2020; 22:12447-12455. [PMID: 32458897 DOI: 10.1039/d0cp01714k] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cryptochromes are a class of flavoproteins proposed as candidates to explain magnetoreception of animals, plants and bacteria. The main hypothesis is that a biradical is formed upon blue-light absorption by flavin adenine dinucleotide (FAD). In a protein milieu, the oxidized form of FAD can be reduced, leading to four redox derivative forms: anionic and neutral semi-reduced radicals, and anionic and neutral fully reduced forms. All these forms have a characteristic electronic absorption spectrum, with a strong vibrational resolution. Here, we carried out a normal mode analysis at the electrostatic embedding QM/MM level of theory to compute the vibrationally resolved absorption spectra of the five redox forms of FAD embedded in a plant cryptochrome. We show that explicitly accounting for vibrational broadening contributions to electronic transitions is essential to reproduce the experimental spectra. In the case of the neutral radical form of FAD, the absorption spectrum is reproduced only if the presence of a tryptophan radical is considered.
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65
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Player TC, Hore PJ. Source of magnetic field effects on the electrocatalytic reduction of CO2. J Chem Phys 2020; 153:084303. [DOI: 10.1063/5.0021643] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Thomas C. Player
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, United Kingdom
| | - P. J. Hore
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, United Kingdom
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66
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Déjean V, Konowalczyk M, Gravell J, Golesworthy MJ, Gunn C, Pompe N, Foster Vander Elst O, Tan KJ, Oxborrow M, Aarts DGAL, Mackenzie SR, Timmel CR. Detection of magnetic field effects by confocal microscopy. Chem Sci 2020; 11:7772-7781. [PMID: 34094150 PMCID: PMC8163210 DOI: 10.1039/d0sc01986k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Certain pairs of paramagnetic species generated under conservation of total spin angular momentum are known to undergo magnetosensitive processes. Two prominent examples of systems exhibiting these so-called magnetic field effects (MFEs) are photogenerated radical pairs created from either singlet or triplet molecular precursors, and pairs of triplet states generated by singlet fission. Here, we showcase confocal microscopy as a powerful technique for the investigation of such phenomena. We first characterise the instrument by studying the field-sensitive chemistry of two systems in solution: radical pairs formed in a cryptochrome protein and the flavin mononucleotide/hen egg-white lysozyme model system. We then extend these studies to single crystals. Firstly, we report temporally and spatially resolved MFEs in flavin-doped lysozyme single crystals. Anisotropic magnetic field effects are then reported in tetracene single crystals. Finally, we discuss the future applications of confocal microscopy for the study of magnetosensitive processes with a particular focus on the cryptochrome-based chemical compass believed to lie at the heart of animal magnetoreception. Confocal microscopy is showcased as a powerful technique for the measurement of spatiotemporally-resolved magnetic field effects in both solutions and single crystals.![]()
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Affiliation(s)
- Victoire Déjean
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory Oxford OX1 3QR UK
| | - Marcin Konowalczyk
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory Oxford OX1 3QR UK .,Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory Oxford OX1 3QZ UK
| | - Jamie Gravell
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory Oxford OX1 3QR UK
| | - Matthew J Golesworthy
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory Oxford OX1 3QR UK
| | - Catlin Gunn
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory Oxford OX1 3QR UK
| | - Nils Pompe
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory Oxford OX1 3QR UK
| | | | - Ke-Jie Tan
- Department of Materials, Imperial College London London SW7 2AZ UK
| | - Mark Oxborrow
- Department of Materials, Imperial College London London SW7 2AZ UK
| | - Dirk G A L Aarts
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory Oxford OX1 3QZ UK
| | - Stuart R Mackenzie
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory Oxford OX1 3QZ UK
| | - Christiane R Timmel
- Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory Oxford OX1 3QR UK .,Centre for Advanced Electron Spin Resonance (CAESR), Department of Chemistry, University of Oxford Oxford OX1 3QR UK
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67
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Effects of intentionally treated water and seeds on the growth of Arabidopsis thaliana. Explore (NY) 2020; 17:55-59. [PMID: 32507494 DOI: 10.1016/j.explore.2020.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 04/20/2020] [Accepted: 04/26/2020] [Indexed: 11/23/2022]
Abstract
OBJECTIVE . A previously reported experiment indicated that Arabidopsis thaliana seeds with cryptochrome mutation His-CRY2 showed more robust photomorphogenic growth when hydrated with intentionally treated water as compared to untreated water. The present study attempted to replicate that outcome, adding a condition where the seeds were also intentionally treated. Arabidopsis seeds were used because they contain a photosensitive flavoprotein called cryptochrome (CRY). CRY has been proposed as a possible "transducer" of intention in living systems because it is thought to have quantum biological properties, and as such, it might potentially be sensitive to quantum observer effects. DESIGN Three Buddhist monks directed their attention toward commercially bottled water and Arabidopsis seeds while holding the intention to improve the growth of the plant. As a control condition, no attention was directed at water or seeds from the same sources. Under double-blinded conditions, treated and untreated seeds were placed in an incubator, hydrated with treated or untreated water, and exposed to either continuous blue light or blue plus far-red light. The seed germination process was repeated three times, each time using new seeds. A 2 × 2 × 2 ANOVA, with water, seeds, and light as factors, was used to analyze the results. RESULTS . Treated water was associated with enhanced photomorphogenic growth, as reflected by a shorter hypocotyl length (p = 0.04) and greater amounts of chlorophyll (p = 0.0005) and anthocyanin (p = 2 × 10-6). Treated seeds resulted in greater amounts of chlorophyll (p = 0.04), but also a longer hypocotyl (p = 0.0004) and less anthocyanin (p = 0.01). Plants exposed to blue plus far-red light were constantly more robust than plants grown under blue light, regardless of the type of water or seed (p < 10-10). CONCLUSION . Intentionally treated water improved the growth of the His-CRY2 variant of Arabidopsis, confirming results of an earlier experiment. Enhanced growth associated with exposure to blue plus far-red light also confirmed to known effects. A more complex relationship was observed with treated seeds. Further research is required to understand the latter outcome, as it may provide clues about the underlying mechanisms of intentional influences.
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68
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Lindoy LP, Fay TP, Manolopoulos DE. Quantum mechanical spin dynamics of a molecular magnetoreceptor. J Chem Phys 2020; 152:164107. [DOI: 10.1063/5.0006411] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Lachlan P. Lindoy
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Thomas P. Fay
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - David E. Manolopoulos
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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69
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Wan G, Liu R, Li C, He J, Pan W, Sword GA, Hu G, Chen F. Change in geomagnetic field intensity alters migration-associated traits in a migratory insect. Biol Lett 2020; 16:20190940. [PMID: 32343935 DOI: 10.1098/rsbl.2019.0940] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Geomagnetic field (GMF) intensity can be used by some animals to determine their position during migration. However, its role, if any, in mediating other migration-related phenotypes remains largely unknown. Here, we simulated variation in GMF intensity between two locations along the migration route of a nocturnal insect migrant, the brown planthopper Nilaparvata lugens, that varied by approximately 5 µT in field intensity. After one generation of exposure, we tested for changes in key morphological, behavioural and physiological traits related to migratory performance, including wing dimorphism, flight capacity and positive phototaxis. Our results showed that all three morphological and behavioural phenotypes responded to a small difference in magnetic field intensity. Consistent magnetic responses in the expression of the phototaxis-related Drosophila-like cryptochrome 1 (Cry1) gene and levels of two primary energy substrates used during flight, triglyceride and trehalose, were also found. Our findings indicate changes in GMF intensity can alter the expression of phenotypes critical for insect migration and highlight the unique role of magnetoreception as a trait that may help migratory insects express potentially beneficial phenotypes in geographically variable environments.
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Affiliation(s)
- Guijun Wan
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Ruiying Liu
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Chunxu Li
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Jinglan He
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Weidong Pan
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Gregory A Sword
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Gao Hu
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
| | - Fajun Chen
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, People's Republic of China
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70
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Babcock N, Kattnig DR. Electron-Electron Dipolar Interaction Poses a Challenge to the Radical Pair Mechanism of Magnetoreception. J Phys Chem Lett 2020; 11:2414-2421. [PMID: 32141754 PMCID: PMC7145362 DOI: 10.1021/acs.jpclett.0c00370] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 03/06/2020] [Indexed: 06/10/2023]
Abstract
A visual magnetic sense in migratory birds has been hypothesized to rely on a radical pair reaction in the protein cryptochrome. In this model, magnetic sensitivity originates from coherent spin dynamics, as the radicals couple to magnetic nuclei via hyperfine interactions. Prior studies have often neglected the electron-electron dipolar (EED) coupling from this hypothesis. We show that EED interactions suppress the anisotropic response to the geomagnetic field by the radical pair mechanism in cryptochrome and that this attenuation is unlikely to be mitigated by mutual cancellation of the EED and electronic exchange coupling, as previously suggested. We then demonstrate that this limitation may be overcome by extending the conventional model to include a third, nonreacting radical. We predict that hyperfine effects could work in concert with three-radical dipolar interactions to tailor a superior magnetic response, thereby providing a new principle for magnetosensitivity with applications for sensing, navigation, and the assessment of biological magnetic field effects.
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Affiliation(s)
- Nathan
S. Babcock
- Living Systems Institute and Department
of Physics, University of Exeter, Stocker Road, Exeter EX4 4QD, United
Kingdom
| | - Daniel R. Kattnig
- Living Systems Institute and Department
of Physics, University of Exeter, Stocker Road, Exeter EX4 4QD, United
Kingdom
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71
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Xiao DW, Hu WH, Cai Y, Zhao N. Magnetic Noise Enabled Biocompass. PHYSICAL REVIEW LETTERS 2020; 124:128101. [PMID: 32281830 DOI: 10.1103/physrevlett.124.128101] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/06/2020] [Indexed: 06/11/2023]
Abstract
The discovery of magnetic protein provides a new understanding of a biocompass at the molecular level. However, the mechanism by which magnetic protein enables a biocompass is still under debate, mainly because of the absence of permanent magnetism in the magnetic protein at room temperature. Here, based on a widely accepted radical pair model of a biocompass, we propose a microscopic mechanism that allows the biocompass to operate without a finite magnetization of the magnetic protein in a biological environment. With the structure of the magnetic protein, we show that the magnetic fluctuation, rather than the permanent magnetism, of the magnetic protein can enable geomagnetic field sensing. An analysis of the quantum dynamics of our microscopic model reveals the necessary conditions for optimal sensitivity. Our work clarifies the mechanism by which magnetic protein enables a biocompass.
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Affiliation(s)
- Da-Wu Xiao
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Wen-Hui Hu
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Yunfeng Cai
- Cognitive Computing Lab, Baidu Research, Beijing 100085, China
| | - Nan Zhao
- Beijing Computational Science Research Center, Beijing 100193, China
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72
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Player TC, Hore PJ. Viability of superoxide-containing radical pairs as magnetoreceptors. J Chem Phys 2020; 151:225101. [PMID: 31837685 DOI: 10.1063/1.5129608] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The ability of night-migratory songbirds to sense the direction of the Earth's magnetic field is increasingly attributed to a photochemical mechanism in which the magnetic field acts on transient radical pairs in cryptochrome flavoproteins located in the birds' eyes. The magnetically sensitive species is commonly assumed to be [FAD•- TrpH•+], formed by sequential light-induced intraprotein electron transfers from a chain of tryptophan residues to the flavin adenine dinucleotide chromophore. However, some evidence points to superoxide, O2 •-, as an alternative partner for the flavin radical. The absence of hyperfine interactions in O2 •- could lead to a more sensitive magnetic compass, but only if the electron spin relaxation of the O2 •- radical is much slower than normally expected for a small mobile radical with an orbitally degenerate electronic ground state. In this study we use spin dynamics simulations to model the sensitivity of a flavin-superoxide radical pair to the direction of a 50 μT magnetic field. By varying parameters that characterize the local environment and molecular dynamics of the radicals, we identify the highly restrictive conditions under which a O2 •--containing radical pair could form the basis of a geomagnetic compass sensor. We conclude that the involvement of superoxide in compass magnetoreception must remain highly speculative until further experimental evidence is forthcoming.
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Affiliation(s)
- Thomas C Player
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
| | - P J Hore
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, United Kingdom
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73
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Fay TP, Lindoy LP, Manolopoulos DE, Hore PJ. How quantum is radical pair magnetoreception? Faraday Discuss 2020; 221:77-91. [DOI: 10.1039/c9fd00049f] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Semiclassical methods cannot accurately simulate magnetic field effects relevant to avian magnetoreception, which may therefore deserve the label “quantum biology”.
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Affiliation(s)
- Thomas P. Fay
- Department of Chemistry
- Physical & Theoretical Chemistry Laboratory
- University of Oxford
- Oxford OX1 3QZ
- UK
| | - Lachlan P. Lindoy
- Department of Chemistry
- Physical & Theoretical Chemistry Laboratory
- University of Oxford
- Oxford OX1 3QZ
- UK
| | - David E. Manolopoulos
- Department of Chemistry
- Physical & Theoretical Chemistry Laboratory
- University of Oxford
- Oxford OX1 3QZ
- UK
| | - P. J. Hore
- Department of Chemistry
- Physical & Theoretical Chemistry Laboratory
- University of Oxford
- Oxford OX1 3QZ
- UK
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74
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Kobylkov D, Wynn J, Winklhofer M, Chetverikova R, Xu J, Hiscock H, Hore PJ, Mouritsen H. Electromagnetic 0.1-100 kHz noise does not disrupt orientation in a night-migrating songbird implying a spin coherence lifetime of less than 10 µs. J R Soc Interface 2019; 16:20190716. [PMID: 31847760 DOI: 10.1098/rsif.2019.0716] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
According to the currently prevailing theory, the magnetic compass sense in night-migrating birds relies on a light-dependent radical-pair-based mechanism. It has been shown that radio waves at megahertz frequencies disrupt magnetic orientation in migratory birds, providing evidence for a quantum-mechanical origin of the magnetic compass. Still, many crucial properties, e.g. the lifetime of the proposed magnetically sensitive radical pair, remain unknown. The current study aims to estimate the spin coherence time of the radical pair, based on the behavioural responses of migratory birds to broadband electromagnetic fields covering the frequency band 0.1-100 kHz. A finding that the birds were unable to use their magnetic compass under these conditions would imply surprisingly long-lived (greater than 10 µs) spin coherence. However, we observed no effect of 0.1-100 kHz radiofrequency (RF) fields on the orientation of night-migratory Eurasian blackcaps (Sylvia atricapilla). This suggests that the lifetime of the spin coherence involved in magnetoreception is shorter than the period of the highest frequency RF fields used in this experiment (i.e. approx. 10 µs). This result, in combination with an earlier study showing that 20-450 kHz electromagnetic fields disrupt magnetic compass orientation, suggests that the spin coherence lifetime of the magnetically sensitive radical pair is in the range 2-10 µs.
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Affiliation(s)
- Dmitry Kobylkov
- AG 'Neurosensorik', University Oldenburg, 26111 Oldenburg, Germany.,Research Centre for Neurosensory Sciences, University Oldenburg, 26111 Oldenburg, Germany
| | - Joe Wynn
- Oxford Navigation Group, Department of Zoology, University of Oxford, Oxford, UK
| | - Michael Winklhofer
- AG 'Neurosensorik', University Oldenburg, 26111 Oldenburg, Germany.,AG 'Sensory Biology of Animals', University Oldenburg, 26111 Oldenburg, Germany
| | - Raisa Chetverikova
- AG 'Neurosensorik', University Oldenburg, 26111 Oldenburg, Germany.,Research Centre for Neurosensory Sciences, University Oldenburg, 26111 Oldenburg, Germany
| | - Jingjing Xu
- AG 'Neurosensorik', University Oldenburg, 26111 Oldenburg, Germany.,Research Centre for Neurosensory Sciences, University Oldenburg, 26111 Oldenburg, Germany
| | - Hamish Hiscock
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - P J Hore
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Henrik Mouritsen
- AG 'Neurosensorik', University Oldenburg, 26111 Oldenburg, Germany.,Research Centre for Neurosensory Sciences, University Oldenburg, 26111 Oldenburg, Germany
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75
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Krylov VV, Chebotareva YV, Izyumov YG. Delayed consequences of the influence of simulated geomagnetic storms on roach Rutilus rutilus embryos. JOURNAL OF FISH BIOLOGY 2019; 95:1422-1429. [PMID: 31589783 DOI: 10.1111/jfb.14150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 09/26/2019] [Indexed: 06/10/2023]
Abstract
This study presents data collected over a 3 year period on the effects of simulated geomagnetic storms (SGMS) on Eurasian roach Rutilus rutilus embryos. Effects were studied during different stages of early development. Rutilis rutilus were raised in ponds for 4 months after exposure to SGMS. The mass, standard length and morphological characteristics of under-yearlings exposed as embryos were recorded. A decrease in length-mass indices in under-yearlings was noted after they had been exposed to SGMS during the first 2 days or during the third and fourth days of early development. Near the time point of 48 h post fertilisation, either no effect or an increased size was observed. In addition, exposure to SGMS led to a redistribution of the vertebral number between the sections of the vertebral column as well as changes in the number of seismosensory system openings in the mandibular and praeoperculum bones of under-yearlings. Observed effects are similar to previously published data on the influence of anthropogenic magnetic fields on roach, namely changes in linear-mass indices, number of vertebrae and number of seismosensory system openings in the mandibular bones of under-yearlings exposed as embryos. Possible mechanisms of magnetic influence on early development of fish are discussed.
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Affiliation(s)
- Viacheslav V Krylov
- Laboratory of Population Biology and Genetics, Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Yaroslavl Oblast, Russian Federation
| | - Yulia V Chebotareva
- Laboratory of Population Biology and Genetics, Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Yaroslavl Oblast, Russian Federation
| | - Yuri G Izyumov
- Laboratory of Population Biology and Genetics, Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Yaroslavl Oblast, Russian Federation
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76
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Binhi VN. Nonspecific magnetic biological effects: A model assuming the spin-orbit coupling. J Chem Phys 2019; 151:204101. [DOI: 10.1063/1.5127972] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- V. N. Binhi
- Prokhorov General Physics Institute, Moscow 119991, Russian Federation
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77
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Nielsen C, Solov’yov IA. MolSpin—Flexible and extensible general spin dynamics software. J Chem Phys 2019; 151:194105. [DOI: 10.1063/1.5125043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Claus Nielsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Ilia A. Solov’yov
- Department of Physics, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
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78
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Navigating at night: fundamental limits on the sensitivity of radical pair magnetoreception under dim light. Q Rev Biophys 2019; 52:e9. [DOI: 10.1017/s0033583519000076] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Abstract
Night-migratory songbirds appear to sense the direction of the Earth's magnetic field via radical pair intermediates formed photochemically in cryptochrome flavoproteins contained in photoreceptor cells in their retinas. It is an open question whether this light-dependent mechanism could be sufficiently sensitive given the low-light levels experienced by nocturnal migrants. The scarcity of available photons results in significant uncertainty in the signal generated by the magnetoreceptors distributed around the retina. Here we use results from Information Theory to obtain a lower bound estimate of the precision with which a bird could orient itself using only geomagnetic cues. Our approach bypasses the current lack of knowledge about magnetic signal transduction and processing in vivo by computing the best-case compass precision under conditions where photons are in short supply. We use this method to assess the performance of three plausible cryptochrome-derived flavin-containing radical pairs as potential magnetoreceptors.
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79
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Maeda K, Naito Y. Dynamics of flavin containing radical pairs in SDS micellar media probed by static and pulse magnetic field effect and pulse ADMR. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1580779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Kiminori Maeda
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Yusuke Naito
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
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80
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Zoltowski BD, Chelliah Y, Wickramaratne A, Jarocha L, Karki N, Xu W, Mouritsen H, Hore PJ, Hibbs RE, Green CB, Takahashi JS. Chemical and structural analysis of a photoactive vertebrate cryptochrome from pigeon. Proc Natl Acad Sci U S A 2019; 116:19449-19457. [PMID: 31484780 PMCID: PMC6765304 DOI: 10.1073/pnas.1907875116] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Computational and biochemical studies implicate the blue-light sensor cryptochrome (CRY) as an endogenous light-dependent magnetosensor enabling migratory birds to navigate using the Earth's magnetic field. Validation of such a mechanism has been hampered by the absence of structures of vertebrate CRYs that have functional photochemistry. Here we present crystal structures of Columba livia (pigeon) CRY4 that reveal evolutionarily conserved modifications to a sequence of Trp residues (Trp-triad) required for CRY photoreduction. In ClCRY4, the Trp-triad chain is extended to include a fourth Trp (W369) and a Tyr (Y319) residue at the protein surface that imparts an unusually high quantum yield of photoreduction. These results are consistent with observations of night migratory behavior in animals at low light levels and could have implications for photochemical pathways allowing magnetosensing.
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Affiliation(s)
- Brian D Zoltowski
- Department of Chemistry, Southern Methodist University, Dallas, TX 75275
- Center for Drug Discovery, Design, and Delivery, Southern Methodist University, Dallas, TX 75275
| | - Yogarany Chelliah
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Anushka Wickramaratne
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Lauren Jarocha
- Department of Chemistry, University of Oxford, OX1 3QZ Oxford, United Kingdom
| | - Nischal Karki
- Department of Chemistry, Southern Methodist University, Dallas, TX 75275
- Center for Drug Discovery, Design, and Delivery, Southern Methodist University, Dallas, TX 75275
| | - Wei Xu
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University of Oldenburg, DE-26111 Oldenburg, Germany
- Research Center for Neurosensory Sciences, University of Oldenburg, DE-26111 Oldenburg, Germany
| | - Peter J Hore
- Department of Chemistry, University of Oxford, OX1 3QZ Oxford, United Kingdom
| | - Ryan E Hibbs
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Carla B Green
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Joseph S Takahashi
- Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390;
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390
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81
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Kerpal C, Richert S, Storey JG, Pillai S, Liddell PA, Gust D, Mackenzie SR, Hore PJ, Timmel CR. Chemical compass behaviour at microtesla magnetic fields strengthens the radical pair hypothesis of avian magnetoreception. Nat Commun 2019; 10:3707. [PMID: 31420558 PMCID: PMC6697675 DOI: 10.1038/s41467-019-11655-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 07/15/2019] [Indexed: 12/02/2022] Open
Abstract
The fact that many animals, including migratory birds, use the Earth's magnetic field for orientation and compass-navigation is fascinating and puzzling in equal measure. The physical origin of these phenomena has not yet been fully understood, but arguably the most likely hypothesis is based on the radical pair mechanism (RPM). Whilst the theoretical framework of the RPM is well-established, most experimental investigations have been conducted at fields several orders of magnitude stronger than the Earth's. Here we use transient absorption spectroscopy to demonstrate a pronounced orientation-dependence of the magnetic field response of a molecular triad system in the field region relevant to avian magnetoreception. The chemical compass response exhibits the properties of an inclination compass as found in migratory birds. The results underline the feasibility of a radical pair based avian compass and also provide further guidelines for the design and operation of exploitable chemical compass systems.
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Affiliation(s)
- Christian Kerpal
- Centre for Advanced Electron Spin Resonance (CÆSR), Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Sabine Richert
- Centre for Advanced Electron Spin Resonance (CÆSR), Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Jonathan G Storey
- Centre for Advanced Electron Spin Resonance (CÆSR), Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK
| | - Smitha Pillai
- School of Molecular Sciences, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85281, USA
| | - Paul A Liddell
- School of Molecular Sciences, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85281, USA
| | - Devens Gust
- School of Molecular Sciences, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ, 85281, USA
| | - Stuart R Mackenzie
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK
| | - P J Hore
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QZ, UK
| | - Christiane R Timmel
- Centre for Advanced Electron Spin Resonance (CÆSR), Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK.
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82
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Atkins C, Bajpai K, Rumball J, Kattnig DR. On the optimal relative orientation of radicals in the cryptochrome magnetic compass. J Chem Phys 2019. [DOI: 10.1063/1.5115445] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Chadsley Atkins
- Institute and Department of Physics, University of Exeter, North Park Road, Exeter EX4 4QL, United Kingdom
| | - Kieran Bajpai
- Institute and Department of Physics, University of Exeter, North Park Road, Exeter EX4 4QL, United Kingdom
| | - Jeremy Rumball
- Institute and Department of Physics, University of Exeter, North Park Road, Exeter EX4 4QL, United Kingdom
| | - Daniel R. Kattnig
- Institute and Department of Physics, University of Exeter, North Park Road, Exeter EX4 4QL, United Kingdom
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom
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83
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Miura T. Studies on coherent and incoherent spin dynamics that control the magnetic field effect on photogenerated radical pairs. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1643510] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Tomoaki Miura
- Department of Science, Niigata University, Niigata, Japan
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84
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Bialas C, Barnard DT, Auman DB, McBride RA, Jarocha LE, Hore PJ, Dutton PL, Stanley RJ, Moser CC. Ultrafast flavin/tryptophan radical pair kinetics in a magnetically sensitive artificial protein. Phys Chem Chem Phys 2019; 21:13453-13461. [PMID: 31187821 PMCID: PMC7301759 DOI: 10.1039/c9cp01916b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Radical pair formation and decay are implicated in a wide range of biological processes including avian magnetoreception. However, studying such biological radical pairs is complicated by both the complexity and relative fragility of natural systems. To resolve open questions about how natural flavin-amino acid radical pair systems are engineered, and to create new systems with novel properties, we developed a stable and highly adaptable de novo artificial protein system. These protein maquettes are designed with intentional simplicity and transparency to tolerate aggressive manipulations that are impractical or impossible in natural proteins. Here we characterize the ultrafast dynamics of a series of maquettes with differing electron-transfer distance between a covalently ligated flavin and a tryptophan in an environment free of other potential radical centers. We resolve the spectral signatures of the cysteine-ligated flavin singlet and triplet states and reveal the picosecond formation and recombination of singlet-born radical pairs. Magnetic field-sensitive triplet-born radical pair formation and recombination occurs at longer timescales. These results suggest that both triplet- and singlet-born radical pairs could be exploited as biological magnetic sensors.
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Affiliation(s)
- Chris Bialas
- Johnson Research Foundation, Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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85
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Nag L, Lukacs A, Vos MH. Short-Lived Radical Intermediates in the Photochemistry of Glucose Oxidase. Chemphyschem 2019; 20:1793-1798. [PMID: 31081986 DOI: 10.1002/cphc.201900329] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/10/2019] [Indexed: 11/07/2022]
Abstract
Glucose oxidase is a flavoprotein that is relatively well-studied as a physico-chemical model system. The flavin cofactor is surrounded by several aromatic acid residues that can act as direct and indirect electron donors to photoexcited flavin. Yet, the identity of the photochemical product states is not well established. We present a detailed full spectral reinvestigation of this issue using femtosecond fluorescence and absorption spectroscopy. Based on a recent characterization of the unstable tyrosine cation radical TyrOH•+ , we now propose that the primary photoproduct involves this species, which was previously not considered. Formation of this product is followed by competing charge recombination and radical pair stabilization reactions that involve proton transfer and radical transfer to tryptophan. A minimal kinetic model is proposed, including a fraction of TyrOH.+ that is stabilized up to the tens of picoseconds timescale, suggesting a potential role of this species as intermediate in biochemical electron transfer reactions.
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Affiliation(s)
- Lipsa Nag
- LOB, CNRS, INSERM, Ecole Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France
| | - Andras Lukacs
- Department of Biophysics, Medical School, University of Pecs, Hungary
| | - Marten H Vos
- LOB, CNRS, INSERM, Ecole Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, France
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86
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Xu JJ, Zhang YC, Wu JQ, Wang WH, Li Y, Wan GJ, Chen FJ, Sword GA, Pan WD. Molecular characterization, spatial-temporal expression and magnetic response patterns of iron-sulfur cluster assembly1 (IscA1) in the rice planthopper, Nilaparvata lugens. INSECT SCIENCE 2019; 26:413-423. [PMID: 29063672 DOI: 10.1111/1744-7917.12546] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 09/14/2017] [Accepted: 09/29/2017] [Indexed: 06/07/2023]
Abstract
The mechanisms of magnetoreception have been proposed as the magnetite-based, the chemical radical-pair and 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 brown planthopper (BPH), Nilaparvata lugens. NlIscA1 contains an open reading frame of 390 bp, encoding amino acids of 129, with the predicted molecular weight of 14.0 kDa and the isoelectric point of 9.10. Well-conserved Fe-S cluster binding sites were observed in the predicted protein. Phylogenetic analysis demonstrated NlIscA1 to be clustered into the insect's IscA1. NlIscA1 showed up-regulated mRNA expression during the period of migration. The mRNA expression of NlIscA1 could be detected in all the three tissues of head, thorax and abdomen, with the highest expression level in the abdomen. For the macropterous migratory Nilaparvata lugens, mRNA expression of NlIscA1 and N. lugens cryptochrome1 (Nlcry1) were up-regulated under the magnetic fields of 5 Gauss and 10 Gauss in strength (vs. local geomagnetic field), while N. lugens cryptochrome2 (Nlcry2) remained stable. For the brachyterous non-migratory Nilaparvata lugens, no significant changes were found in mRNA expression of NlIscA1, Nlcry1 and Nlcry2 among different magnetic fields. These findings preliminarily reveal that the expression of NlIscA1 and Nlcry1 exhibited coordinated responses to the magnetic field. It suggests some potential associations among the putative magneto-sensitive molecules of cryptochrome and iron-sulfur cluster assembly.
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Affiliation(s)
- Jing-Jing Xu
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ying-Chao Zhang
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jian-Qi Wu
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Wei-Hong Wang
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yue Li
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Gui-Jun Wan
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Fa-Jun Chen
- Department of Entomology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Gregory A Sword
- Department of Entomology, Texas A&M University, College Station, TX, USA
| | - Wei-Dong Pan
- Beijing Key Laboratory of Bioelectromagnetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
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87
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Juutilainen J, Herrala M, Luukkonen J, Naarala J, Hore PJ. Magnetocarcinogenesis: is there a mechanism for carcinogenic effects of weak magnetic fields? Proc Biol Sci 2019; 285:rspb.2018.0590. [PMID: 29794049 DOI: 10.1098/rspb.2018.0590] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Accepted: 04/27/2018] [Indexed: 12/13/2022] Open
Abstract
Extremely low-frequency (ELF) magnetic fields have been classified as possibly carcinogenic, mainly based on rather consistent epidemiological findings suggesting a link between childhood leukaemia and 50-60 Hz magnetic fields from power lines. However, causality is not the only possible explanation for the epidemiological associations, as animal and in vitro experiments have provided only limited support for carcinogenic effects of ELF magnetic fields. Importantly, there is no generally accepted biophysical mechanism that could explain such effects. In this review, we discuss the possibility that carcinogenic effects are based on the radical pair mechanism (RPM), which seems to be involved in magnetoreception in birds and certain other animals, allowing navigation in the geomagnetic field. We review the current understanding of the RPM in magnetoreception, and discuss cryptochromes as the putative magnetosensitive molecules and their possible links to cancer-relevant biological processes. We then propose a hypothesis for explaining the link between ELF fields and childhood leukaemia, discuss the strengths and weaknesses of the current evidence, and make proposals for further research.
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Affiliation(s)
- Jukka Juutilainen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Mikko Herrala
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Jukka Luukkonen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - Jonne Naarala
- Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
| | - P J Hore
- Department of Chemistry, University of Oxford, Oxford, UK
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88
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Hore PJ. Upper bound on the biological effects of 50/60 Hz magnetic fields mediated by radical pairs. eLife 2019; 8:44179. [PMID: 30801245 PMCID: PMC6417859 DOI: 10.7554/elife.44179] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 02/02/2019] [Indexed: 01/02/2023] Open
Abstract
Prolonged exposure to weak (~1 μT) extremely-low-frequency (ELF, 50/60 Hz) magnetic fields has been associated with an increased risk of childhood leukaemia. One of the few biophysical mechanisms that might account for this link involves short-lived chemical reaction intermediates known as radical pairs. In this report, we use spin dynamics simulations to derive an upper bound of 10 parts per million on the effect of a 1 μT ELF magnetic field on the yield of a radical pair reaction. By comparing this figure with the corresponding effects of changes in the strength of the Earth’s magnetic field, we conclude that if exposure to such weak 50/60 Hz magnetic fields has any effect on human biology, and results from a radical pair mechanism, then the risk should be no greater than travelling a few kilometres towards or away from the geomagnetic north or south pole.
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Affiliation(s)
- P J Hore
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, Oxford, United Kingdom
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89
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Xu L, Wen B, Shao W, Yao P, Zheng W, Zhou Z, Zhang Y, Zhu G. Impacts of Cys392, Asp393, and ATP on the FAD Binding, Photoreduction, and the Stability of the Radical State of Chlamydomonas reinhardtii Cryptochrome. Chembiochem 2019; 20:940-948. [PMID: 30548754 DOI: 10.1002/cbic.201800660] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Indexed: 12/16/2022]
Abstract
Plant cryptochromes (CRYs) are blue-light receptors that regulate light-dependent growth, development, and circadian rhythms. A flavin adenine dinucleotide (FAD) cofactor is bound to the photolyase homology region (PHR) of plant CRYs and can be photoreduced to a neutral radical state under blue light. This photoreaction can trigger subsequent signal transduction. Plant CRYs can also bind an ATP molecule adjacent to FAD in a pocket of the PHR. Chlamydomonas reinhardtii contains a single plant CRY, named Chlamydomonas photolyase homologue 1 (CPH1). In CPH1, Cys392 and Asp393 are located near the FAD cofactor. Here we have shown that replacing Cys392 with Ser has little effect on the properties of CPH1. The C392N mutant, however, showed a faster photoreduction rate than wild-type CPH1, together with a significantly lower oxidation rate of the neutral radical state. Substituting an Asn residue for Asp393 in CPH1 improved the binding affinity for FAD as well as the stability of the neutral radical, but photoreduction in the case of this mutant was severely inhibited. In the presence of ATP, CPH1 and its mutants exhibited significantly higher binding affinity for FAD and slower oxidation of the neutral radical. These results reveal that the residues at site 392 and the presence of ATP can tune the stability of the neutral radical, that the Asp residue at site 393 is crucial for photoreduction, and that the photoreduction rate is not determined merely by the stability of the neutral radical in CPH1.
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Affiliation(s)
- Lei Xu
- Anhui Province Key Laboratory of Active Biological Macromolecules, Wannan Medical College, 22# Wenchang West Road, Wuhu, 241002, Anhui, P. R. China
| | - Bin Wen
- Institute of Molecular Biology and Biotechnology, Anhui Normal University, 1# Beijing East Road, Wuhu, 241000, Anhui, P. R. China
| | - Wengui Shao
- Anhui Province Key Laboratory of Active Biological Macromolecules, Wannan Medical College, 22# Wenchang West Road, Wuhu, 241002, Anhui, P. R. China
| | - Pengcheng Yao
- Anhui Province Key Laboratory of Active Biological Macromolecules, Wannan Medical College, 22# Wenchang West Road, Wuhu, 241002, Anhui, P. R. China
| | - Wei Zheng
- Anhui Province Key Laboratory of Active Biological Macromolecules, Wannan Medical College, 22# Wenchang West Road, Wuhu, 241002, Anhui, P. R. China
| | - Zhiqiang Zhou
- Anhui Province Key Laboratory of Active Biological Macromolecules, Wannan Medical College, 22# Wenchang West Road, Wuhu, 241002, Anhui, P. R. China
| | - Yao Zhang
- Anhui Province Key Laboratory of Active Biological Macromolecules, Wannan Medical College, 22# Wenchang West Road, Wuhu, 241002, Anhui, P. R. China
| | - Guoping Zhu
- Institute of Molecular Biology and Biotechnology, Anhui Normal University, 1# Beijing East Road, Wuhu, 241000, Anhui, P. R. China
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90
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Pooam M, Arthaut LD, Burdick D, Link J, Martino CF, Ahmad M. Magnetic sensitivity mediated by the Arabidopsis blue-light receptor cryptochrome occurs during flavin reoxidation in the dark. PLANTA 2019; 249:319-332. [PMID: 30194534 DOI: 10.1007/s00425-018-3002-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/29/2018] [Indexed: 05/20/2023]
Abstract
Arabidopsis cryptochrome mediates responses to magnetic fields that have been applied in the absence of light, consistent with flavin reoxidation as the primary detection mechanism. Cryptochromes are highly conserved blue-light-absorbing flavoproteins which have been linked to the perception of electromagnetic stimuli in numerous organisms. These include sensing the direction of the earth's magnetic field in migratory birds and the intensity of magnetic fields in insects and plants. When exposed to light, cryptochromes undergo flavin reduction/reoxidation redox cycles leading to biological activation which generate radical pairs thought to be the basis for magnetic sensitivity. However, the nature of the magnetically sensitive radical pairs and the steps at which they act during the cryptochrome redox cycle are currently a matter of debate. Here, we investigate the response of Arabidopsis cryptochrome-1 in vivo to a static magnetic field of 500 μT (10 × earth's field) using both plant growth and light-dependent phosphorylation as an assay. Cryptochrome responses to light were enhanced by the magnetic field, as indicated by increased inhibition of hypocotyl elongation and increased cryptochrome phosphorylation. However, when light and dark intervals were given intermittently, a plant response to the magnetic field was observed even when the magnetic field was given exclusively during the dark intervals between light exposures. This indicates that the magnetically sensitive reaction step in the cryptochrome photocycle must occur during flavin reoxidation, and likely involves the formation of reactive oxygen species.
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Affiliation(s)
- Marootpong Pooam
- Sorbonne Universités, CNRS, UMR8256, IBPS, Photobiology Research Group, 7 Quai St. Bernard, 75005, Paris, France
| | - Louis-David Arthaut
- Sorbonne Universités, CNRS, UMR8256, IBPS, Photobiology Research Group, 7 Quai St. Bernard, 75005, Paris, France
| | - Derek Burdick
- Sorbonne Universités, CNRS, UMR8256, IBPS, Photobiology Research Group, 7 Quai St. Bernard, 75005, Paris, France
- Xavier University, 3800 Victory Parkway, Cincinnati, OH, 45207, USA
| | - Justin Link
- Xavier University, 3800 Victory Parkway, Cincinnati, OH, 45207, USA
| | - Carlos F Martino
- Department of Biomedical Engineering, Florida Institute of Technology, 150W University Blvd, Melbourne, FL, 32901, USA
| | - Margaret Ahmad
- Sorbonne Universités, CNRS, UMR8256, IBPS, Photobiology Research Group, 7 Quai St. Bernard, 75005, Paris, France.
- Xavier University, 3800 Victory Parkway, Cincinnati, OH, 45207, USA.
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91
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Sannikova VA, Davydova MP, Sherin PS, Babenko SV, Korolev VV, Stepanov AA, Nikul'shin PV, Kalneus EV, Vasilevsky SF, Benassi E, Melnikov AR. Determination of Hyperfine Coupling Constants of Fluorinated Diphenylacetylene Radical Anions by Magnetic Field-Affected Reaction Yield Spectroscopy. J Phys Chem A 2019; 123:505-516. [PMID: 30566354 DOI: 10.1021/acs.jpca.8b10306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Magnetic field-affected reaction yield (MARY) spectroscopy is a spin chemistry technique for detecting short-lived radical ions. Having sensitivity to transient species with lifetimes as short as nanoseconds, MARY spectroscopy usually does not provide detailed information on their magnetic resonance parameters, except for simple systems with equivalent magnetic nuclei. In this work, the radical anions of two fluorinated diphenylacetylene derivatives with nonequivalent magnetic nuclei and unknown hyperfine coupling constants ( AHF) were investigated by MARY spectroscopy. The MARY spectra were found to be resolved and have resonance lines in nonzero magnetic fields, which are determined by the AHF values. Simple relationships between the positions of resonance MARY lines and the AHF values were established from the analysis of the different Hamiltonian block contributions to the MARY spectrum. The obtained experimental AHF values are in agreement with the results of quantum chemical calculations at the density functional theory level.
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Affiliation(s)
- Victoria A Sannikova
- Institute of Chemical Kinetics and Combustion SB RAS , 3, Institutskaya Str. , 630090 Novosibirsk , Russian Federation.,Novosibirsk State University , 2, Pirogova Str. , 630090 Novosibirsk , Russian Federation
| | - Maria P Davydova
- Institute of Chemical Kinetics and Combustion SB RAS , 3, Institutskaya Str. , 630090 Novosibirsk , Russian Federation.,A.V. Nikolaev Institute of Inorganic Chemistry SB RAS , 3, Akademika Lavrentieva Ave. , 630090 Novosibirsk , Russian Federation
| | - Peter S Sherin
- Novosibirsk State University , 2, Pirogova Str. , 630090 Novosibirsk , Russian Federation.,International Tomography Center , 3a, Institutskaya Str. , 630090 Novosibirsk , Russian Federation
| | - Simon V Babenko
- Institute of Chemical Kinetics and Combustion SB RAS , 3, Institutskaya Str. , 630090 Novosibirsk , Russian Federation
| | - Valeri V Korolev
- Institute of Chemical Kinetics and Combustion SB RAS , 3, Institutskaya Str. , 630090 Novosibirsk , Russian Federation
| | - Alexander A Stepanov
- Institute of Chemical Kinetics and Combustion SB RAS , 3, Institutskaya Str. , 630090 Novosibirsk , Russian Federation.,Novosibirsk State University , 2, Pirogova Str. , 630090 Novosibirsk , Russian Federation
| | - Pavel V Nikul'shin
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS , 9, Akademika Lavrentieva Ave. , 630090 Novosibirsk , Russian Federation
| | - Evgeny V Kalneus
- Institute of Chemical Kinetics and Combustion SB RAS , 3, Institutskaya Str. , 630090 Novosibirsk , Russian Federation
| | - Sergei F Vasilevsky
- Institute of Chemical Kinetics and Combustion SB RAS , 3, Institutskaya Str. , 630090 Novosibirsk , Russian Federation.,Novosibirsk State University , 2, Pirogova Str. , 630090 Novosibirsk , Russian Federation
| | - Enrico Benassi
- Novosibirsk State University , 2, Pirogova Str. , 630090 Novosibirsk , Russian Federation.,Department of Chemistry , Hexi University , 734000 Zhangye , China
| | - Anatoly R Melnikov
- Institute of Chemical Kinetics and Combustion SB RAS , 3, Institutskaya Str. , 630090 Novosibirsk , Russian Federation.,Novosibirsk State University , 2, Pirogova Str. , 630090 Novosibirsk , Russian Federation
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92
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Chang H, Guo JL, Fu XW, Wang ML, Hou YM, Wu KM. Molecular Characterization and Expression Profiles of Cryptochrome Genes in a Long-Distance Migrant, Agrotis segetum (Lepidoptera: Noctuidae). JOURNAL OF INSECT SCIENCE (ONLINE) 2019; 19:5299137. [PMID: 30690535 PMCID: PMC6342827 DOI: 10.1093/jisesa/iey127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Indexed: 06/09/2023]
Abstract
Cryptochromes act as photoreceptors or integral components of the circadian clock that involved in the regulation of circadian clock and regulation of migratory activity in many animals, and they may also act as magnetoreceptors that sensed the direction of the Earth's magnetic field for the purpose of navigation during animals' migration. Light is a major environmental signal for insect circadian rhythms, and it is also necessary for magnetic orientation. We identified the full-length cDNA encoding As-CRY1 and As-CRY2 in Agrotis segetum Denis and Schiffermaller (turnip moth (Lepidoptera: Noctuidae)). The DNA photolyase domain and flavin adenine dinucleotide-binding domain were found in both cry genes, and multiple alignments showed that those domains that are important for the circadian clock and magnetosensing were highly conserved among different animals. Quantitative polymerase chain reaction showed that cry genes were expressed in all examined body parts, with higher expression in adults during the developmental stages of the moths. Under a 14:10 (L:D) h cycle, the expression of cry genes showed a daily biological rhythm, and light can affect the expression levels of As-cry genes. The expression levels of cry genes were higher in the migratory population than in the reared population and higher in the emigration population than in the immigration population. These findings suggest that the two cryptochrome genes characterized in the turnip moth might be associated with the circadian clock and magnetosensing. Their functions deserve further study, especially for potential control of the turnip moth.
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Affiliation(s)
- Hong Chang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops and Fujian Province Key Laboratory of Insect Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jiang-Long Guo
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Plant Protection, Shenyang Agricultural University, Shenyang, China
| | - Xiao-Wei Fu
- Department of Plant Protection, Henan Institute of Science and Technology, Xinxiang, China
| | - Meng-Lun Wang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Department of Entomology, China Agricultural University, Beijing, China
| | - You-Ming Hou
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops and Fujian Province Key Laboratory of Insect Ecology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Kong-Ming Wu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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93
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Ikeya N, Nasibulov EA, Ivanov KL, Maeda K, Woodward JR. Single-molecule spectroscopy of radical pairs, a theoretical treatment and experimental considerations. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1559954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Noboru Ikeya
- Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan
| | - Egor A. Nasibulov
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Novosibirsk, Russia
- Physics Department, Novosibirsk State University, Novosibirsk, Russia
- A. P. Ershov Institute of Informatics Systems, Siberian Branch of the Russian Academy of Science, Novosibirsk, Russia
| | - Konstantin L. Ivanov
- International Tomography Center, Siberian Branch of the Russian Academy of Science, Novosibirsk, Russia
- Physics Department, Novosibirsk State University, Novosibirsk, Russia
| | - Kiminori Maeda
- Graduate School of Science and Engineering, Saitama University, Saitama City, Japan
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94
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Miura T, Maeda K, Oka Y, Ikoma T. Gigantic Magnetic Field Effect on the Long-Lived Intermolecular Charge-Separated State Created at the Nonionic Bilayer Membrane. J Phys Chem B 2018; 122:12173-12183. [PMID: 30444615 DOI: 10.1021/acs.jpcb.8b08389] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
For realization of low-cost organic photon-energy conversion, the supramolecular approach has been a focus of attention as a counter approach to precise synthesis of covalently linked donor (D)-acceptor (A) molecules. Here we report photogeneration of a long-lived (∼3 μs) intermolecular charge-separated (CS) state of metal porphyrins (D) and an alkyl viologen (A) at an interface of a vesicle membrane formed by self-assembly of nonionic surfactant and cholesterol molecules. The yield of escaped free radicals is negligibly low as in the case of CS states in covalently linked D-A systems. Furthermore, the transient concentration of the CS state dramatically increases by ∼100% upon application of a magnetic field of 250 mT at room temperature. The simulation of the spin dynamics of the CS state indicates that fast (∼107 s-1) spin-selective recombination and slow (105-106 s-1) dissociation-re-encounter dynamics are the key processes for the long CS-state lifetime and the gigantic magnetic field effect. It has turned out that such dynamics are sharply dependent on temperature and alkyl chain length of the viologen. The present results would lead to the development of future materials for light energy conversion, drug delivery, and microscopic bioprobes.
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Affiliation(s)
- Tomoaki Miura
- Department of Chemistry , Niigata University , 2-8050 Ikarashi, Nishi-ku , Niigata 950-2181 , Japan
| | - Kiminori Maeda
- Department of Chemistry, Graduate School of Science and Engineering , Saitama University , 255 Shimo-okubo, Sakura-ku , Saitama 338-8570 , Japan
| | - Yoshimi Oka
- Frontier Research Core for Life Sciences , University of Toyama , 2630 Sugitani , Toyama 930-0194 , Japan
| | - Tadaaki Ikoma
- Department of Chemistry , Niigata University , 2-8050 Ikarashi, Nishi-ku , Niigata 950-2181 , Japan.,Center for Coordination of Research Facilities , Niigata University , 2-8050 Ikarashi, Nishi-ku , Niigata 950-2181 , Japan
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95
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Wang X, Jing C, Selby CP, Chiou YY, Yang Y, Wu W, Sancar A, Wang J. Comparative properties and functions of type 2 and type 4 pigeon cryptochromes. Cell Mol Life Sci 2018; 75:4629-4641. [PMID: 30264181 PMCID: PMC6383368 DOI: 10.1007/s00018-018-2920-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 08/20/2018] [Accepted: 09/18/2018] [Indexed: 10/28/2022]
Abstract
Two types of vertebrate cryptochromes (Crys) are currently recognized. Type 2 Crys function in the molecular circadian clock as light-independent transcriptional repressors. Type 4 Crys are a newly discovered group with unknown function, although they are flavoproteins, and therefore, may function as photoreceptors. It has been postulated that Crys function in light-dependent magnetoreception, which is thought to contribute towards homing and migratory behaviors. Here we have cloned and annotated the full-length pigeon ClCry1, ClCry2, and ClCry4 genes, and characterized the full-length proteins and several site-directed mutants to investigate the roles of these proteins. ClCry1 and ClCry2 are phylogenetically grouped as Type 2 Crys and thus are expected to be core components of the pigeon circadian clock. Interestingly, we find that ClCry4 is properly annotated as a Type 4 Cry. It appears that many birds possess a Type 4 Cry which, as in pigeon, is misannotated. Like the Type 2 Crys, ClCry4 is widespread in pigeon tissues. However, unlike the Type 2 Crys, ClCry4 is cytosolic, and purified ClCry4 possesses FAD cofactor, which confers characteristic UV-Vis spectra as well as two photochemical activities. We find that ClCry4 undergoes light-dependent conformational change, which is a property of insect Type 1 Crys involved in the insect-specific pathway of photoentrainment of the biological clock. ClCry4 can also be photochemically reduced by a mechanism common to all FAD-containing Cry family members, and this mechanism is postulated to be influenced by the geomagnetic field. Thus pigeon Crys control circadian behavior and may also have photosensory function.
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Affiliation(s)
- Xuefeng Wang
- College of Science, National University of Defense Technology, Changsha, 410073, Hunan, People's Republic of China
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
| | - Chengyu Jing
- College of Science, National University of Defense Technology, Changsha, 410073, Hunan, People's Republic of China
| | - Christopher P Selby
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
| | - Yi-Ying Chiou
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
- Institute of Biochemistry, National Chung Hsing University, Taichung, Taiwan
| | - Yanyan Yang
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA
| | - Wenjian Wu
- College of Science, National University of Defense Technology, Changsha, 410073, Hunan, People's Republic of China
| | - Aziz Sancar
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA.
| | - Jing Wang
- College of Science, National University of Defense Technology, Changsha, 410073, Hunan, People's Republic of China.
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96
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Worster SB, Hore PJ. Proposal to use superparamagnetic nanoparticles to test the role of cryptochrome in magnetoreception. J R Soc Interface 2018; 15:20180587. [PMID: 30381345 PMCID: PMC6228473 DOI: 10.1098/rsif.2018.0587] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 10/08/2018] [Indexed: 11/12/2022] Open
Abstract
Evidence is accumulating to support the hypothesis that some animals use light-induced radical pairs to detect the direction of the Earth's magnetic field. Cryptochrome proteins seem to be involved in the sensory pathway but it is not yet clear if they are the magnetic sensors: they could, instead, play a non-magnetic role as signal transducers downstream of the primary sensor. Here we propose an experiment with the potential to distinguish these functions. The principle is to use superparamagnetic nanoparticles to disable any magnetic sensing role by enhancing the electron spin relaxation of the radicals so as to destroy their spin correlation. We use spin dynamics simulations to show that magnetoferritin, a synthetic, protein-based nanoparticle, has the required properties. If cryptochrome is the primary sensor, then it should be inactivated by a magnetoferritin particle placed 12-16 nm away. This would prevent a bird from using its magnetic compass in behavioural tests and abolish magnetically sensitive neuronal firing in the retina. The key advantage of such an experiment is that any signal transduction role should be completely unaffected by the tiny magnetic interactions (≪kBT) required to enhance the spin relaxation of the radical pair.
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Affiliation(s)
- Susannah Bourne Worster
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK
| | - P J Hore
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ, UK
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97
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Vanderstraeten J, Gailly P, Malkemper EP. Corrigendum: Low-Light Dependence of the Magnetic Field Effect on Cryptochromes: Possible Relevance to Plant Ecology. FRONTIERS IN PLANT SCIENCE 2018; 9:1459. [PMID: 30310387 PMCID: PMC6173225 DOI: 10.3389/fpls.2018.01459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 09/12/2018] [Indexed: 06/08/2023]
Abstract
[This corrects the article DOI: 10.3389/fpls.2018.00121.].
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Affiliation(s)
- Jacques Vanderstraeten
- Environmental and Work Health Research Center, School of Public Health, Université Libre de Bruxelles, Brussels, Belgium
| | - Philippe Gailly
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - E. Pascal Malkemper
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Essen, Germany
- Department of Wildlife Management, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Praha, Czechia
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98
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Antill LM, Takizawa SY, Murata S, Woodward JR. Photoinduced flavin-tryptophan electron transfer across vesicle membranes generates magnetic field sensitive radical pairs. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1524525] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Lewis M. Antill
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Shin-ya Takizawa
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Shigeru Murata
- Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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99
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Keens RH, Bedkihal S, Kattnig DR. Magnetosensitivity in Dipolarly Coupled Three-Spin Systems. PHYSICAL REVIEW LETTERS 2018; 121:096001. [PMID: 30230901 DOI: 10.1103/physrevlett.121.096001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Indexed: 06/08/2023]
Abstract
The radical pair mechanism is a canonical model for the magnetosensitivity of chemical reaction processes. The key ingredient of this model is the hyperfine interaction that induces a coherent mixing of singlet and triplet electron spin states in pairs of radicals, thereby facilitating magnetic field effects (MFEs) on reaction yields through spin-selective reaction channels. We show that the hyperfine interaction is not a categorical requirement to realize the sensitivity of radical reactions to weak magnetic fields. We propose that, in systems comprising three instead of two radicals, dipolar interactions provide an alternative pathway for MFEs. By considering the role of symmetries and energy level crossings, we present a model that demonstrates a directional sensitivity to fields weaker than the geomagnetic field and remarkable spikes in the reaction yield as a function of the magnetic field intensity; these effects can moreover be tuned by the exchange interaction. Our results further the current understanding of the effects of weak magnetic fields on chemical reactions, could pave the way to a clearer understanding of the mysteries of magnetoreception and other biological MFEs and motivate the design of quantum sensors. Further still, this phenomenon will affect spin systems used in quantum information processing in the solid state and may also be applicable to spintronics.
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Affiliation(s)
- Robert H Keens
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, United Kingdom
| | - Salil Bedkihal
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, United Kingdom
| | - Daniel R Kattnig
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter, Devon, EX4 4QD, United Kingdom
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100
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Nielsen C, Kattnig DR, Sjulstok E, Hore PJ, Solov'yov IA. Ascorbic acid may not be involved in cryptochrome-based magnetoreception. J R Soc Interface 2018; 14:rsif.2017.0657. [PMID: 29263128 DOI: 10.1098/rsif.2017.0657] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/28/2017] [Indexed: 01/13/2023] Open
Abstract
Seventeen years after it was originally suggested, the photoreceptor protein cryptochrome remains the most probable host for the radical pair intermediates that are thought to be the sensors in the avian magnetic compass. Although evidence in favour of this hypothesis is accumulating, the intracellular interaction partners of the sensory protein are still unknown. It has been suggested that ascorbate ions could interact with surface-exposed tryptophan radicals in photoactivated cryptochromes, and so lead to the formation of a radical pair comprised of the reduced form of the flavin adenine dinucleotide cofactor, FAD•-, and the ascorbate radical, Asc•- This species could provide a more sensitive compass than a FAD-tryptophan radical pair. In this study of Drosophila melanogaster cryptochrome and Erithacus rubecula (European robin) cryptochrome 1a, we use molecular dynamics simulations to characterize the transient encounters of ascorbate ions with tryptophan radicals in cryptochrome in order to assess the likelihood of the [FAD•- Asc•-]-pathway. It is shown that ascorbate ions are expected to bind near the tryptophan radicals for periods of a few nanoseconds. The rate at which these encounters happen is low, and it is therefore concluded that ascorbate ions are unlikely to be involved in magnetoreception if the ascorbate concentration is only of the order of 1 mM or less.
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Affiliation(s)
- Claus Nielsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Daniel R Kattnig
- Living Systems Institute and Department of Physics, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Emil Sjulstok
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - P J Hore
- Department of Chemistry, Physical & Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK
| | - Ilia A Solov'yov
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
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