1
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Romanova N, Utvenko G, Prokshina A, Cellarius F, Fedorishcheva A, Pakhomov A. Migratory birds are able to choose the appropriate migratory direction under dim yellow narrowband light. Proc Biol Sci 2023; 290:20232499. [PMID: 38113940 PMCID: PMC10730290 DOI: 10.1098/rspb.2023.2499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 11/21/2023] [Indexed: 12/21/2023] Open
Abstract
Currently, it is generally assumed that migratory birds are oriented in the appropriate migratory direction under UV, blue and green light (short-wavelength) and are unable to use their magnetic compass in total darkness and under yellow and red light (long-wavelength). However, it has also been suggested that the magnetic compass has two sensitivity peaks: in the short and long wavelengths, but with different intensities. In this project, we aimed to study the orientation of long-distance migrants, pied flycatchers (Ficedula hypoleuca), under different narrowband light conditions during autumn and spring migrations. The birds were tested in the natural magnetic field (NMF) and a changed magnetic field (CMF) rotated counterclockwise by 120° under dim green (autumn) and yellow (spring and autumn) light, which are on the 'threshold' between the short-wavelength and long-wavelength light. We showed that pied flycatchers (i) were completely disoriented under green light both in the NMF and CMF but (ii) showed the migratory direction in the NMF and the appropriate response to CMF under yellow light. Our data contradict the results of previous experiments under narrowband green and yellow light and raise doubts about the existence of only short-wavelength magnetoreception. The parameters of natural light change dramatically in spectral composition and intensity after local sunset, and the avian magnetic compass should be adapted to function properly under such constantly changing light conditions.
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Affiliation(s)
- Nadezhda Romanova
- Moscow State Pedagogical University, 1/1 M. Pirogovskaya St., Moscow 119991, Russia
| | - Gleb Utvenko
- Department of Vertebrate Zoology, St. Petersburg State University, 199034 St. Petersburg, Russia
- Biological Station Rybachy, Zoological Institute RAS, Kaliningrad Region, Rybachy 238535, Russia
| | - Anisia Prokshina
- Department of Vertebrate Zoology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Fyodor Cellarius
- Department of Vertebrate Zoology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | | | - Alexander Pakhomov
- Biological Station Rybachy, Zoological Institute RAS, Kaliningrad Region, Rybachy 238535, Russia
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2
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Muheim R, Phillips JB. Effects of low-level RF fields reveal complex pattern of magnetic input to the avian magnetic compass. Sci Rep 2023; 13:19970. [PMID: 37968316 PMCID: PMC10651899 DOI: 10.1038/s41598-023-46547-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 11/02/2023] [Indexed: 11/17/2023] Open
Abstract
The avian magnetic compass can be disrupted by weak narrow-band and broadband radio-frequency (RF) fields in the lower MHz range. However, it is unclear whether disruption of the magnetic compass results from the elimination of the perception pattern produced by the magnetic field or from qualitative changes that make the pattern unrecognizable. We show that zebra finches trained in a 4-arm maze to orient relative to the magnetic field are disoriented when tested in the presence of low-level (~ 10 nT) Larmor-frequency RF fields. However, they are able to orient when tested in such RF fields if trained under this condition, indicating that the RF field alters, but does not eliminate, the magnetic input. Larmor-frequency RF fields of higher intensities, with or without harmonics, dramatically alter the magnetic compass response. In contrast, exposure to broadband RF fields in training, in testing, or in both training and testing eliminates magnetic compass information. These findings demonstrate that low-level RF fields at intensities found in many laboratory and field experiments may have very different effects on the perception of the magnetic field in birds, depending on the type and intensity of the RF field, and the birds' familiarity with the RF-generated pattern.
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Affiliation(s)
- Rachel Muheim
- Department of Biology, Lund University, Biology Building, 223 62, Lund, Sweden.
| | - John B Phillips
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA, 24061-0406, USA
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3
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Geomagnetic disturbance associated with increased vagrancy in migratory landbirds. Sci Rep 2023; 13:414. [PMID: 36624156 PMCID: PMC9829733 DOI: 10.1038/s41598-022-26586-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/16/2022] [Indexed: 01/11/2023] Open
Abstract
Rare birds known as "accidentals" or "vagrants" have long captivated birdwatchers and puzzled biologists, but the drivers of these rare occurrences remain elusive. Errors in orientation or navigation are considered one potential driver: migratory birds use the Earth's magnetic field-sensed using specialized magnetoreceptor structures-to traverse long distances over often unfamiliar terrain. Disruption to these magnetoreceptors or to the magnetic field itself could potentially cause errors leading to vagrancy. Using data from 2 million captures of 152 landbird species in North America over 60 years, we demonstrate a strong association between disruption to the Earth's magnetic field and avian vagrancy during fall migration. Furthermore, we find that increased solar activity-a disruptor of the avian magnetoreceptor-generally counteracts this effect, potentially mitigating misorientation by disabling the ability for birds to use the magnetic field to orient. Our results link a hypothesized cause of misorientation to the phenomenon of avian vagrancy, further demonstrating the importance of magnetoreception among the orientation mechanisms of migratory birds. Geomagnetic disturbance may have important downstream ecological consequences, as vagrants may experience increased mortality rates or facilitate range expansions of avian populations and the organisms they disperse.
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4
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Sensitivity threshold of avian magnetic compass to oscillating magnetic field is species-specific. Behav Ecol Sociobiol 2023. [DOI: 10.1007/s00265-022-03282-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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5
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Pakhomov A, Prokshina A, Cellarius F, Mouritsen H, Chernetsov N. Access to the sky near the horizon and stars does not play a crucial role in compass calibration of European songbird migrants. J Exp Biol 2022; 225:276374. [PMID: 35903997 DOI: 10.1242/jeb.243631] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 07/27/2022] [Indexed: 11/20/2022]
Abstract
Migratory birds use different global cues including celestial and magnetic information to determine and maintain their seasonally appropriate migratory direction. A hierarchy among different compass systems in songbird migrants is still a matter for discussion due to highly variable and apparently contradictory results obtained in various experimental studies. How birds decide whether or not and how they should calibrate their compasses before departure remains unclear. A recent "extended unified theory" suggested that access to both a view of the sky near the horizon and stars during the cue-conflict exposure might be crucial for the results of cue-conflict experiments. In this study, we performed cue-conflict experiments in three European songbird species with different migratory strategies (garden warblers Sylvia borin, pied flycatcher Ficedula hypoleuca and European robin Erithacus rubecula; juveniles and adults; spring and autumn migrations) using a uniform experimental protocol. We exposed birds to the natural celestial cues in a shifted (120° clock/counterclockwise) magnetic field from sunset to the end of the nautical twilight and tested them in orientation cages immediately after cue-conflict treatments. None of the species (apart from adult robins) showed any sign of calibration even if they had access to a view of the sky and local surroundings near the horizon and stars during cue-conflict treatments. Based on results of our experiments and data of previous contradictory studies, we suggest that no uniform theory can explain why birds calibrate or do not calibrate their compass systems. Each species (and possibly even different populations) may choose its calibration strategy differently.
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Affiliation(s)
- Alexander Pakhomov
- Biological Station Rybachy, Zoological Institute RAS, Rybachy 238535, Kaliningrad Region, Russia
| | - Anisia Prokshina
- Department of Vertebrate Zoology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Fedor Cellarius
- Department of Vertebrate Zoology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, Carl-von-Ossietzky-Universität Oldenburg, 26111 Oldenburg, Germany.,Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-University Oldenburg, Carl-von-Ossietzky-Strasse 9-11, 26129 Oldenburg, Germany
| | - Nikita Chernetsov
- Biological Station Rybachy, Zoological Institute RAS, Rybachy 238535, Kaliningrad Region, Russia.,Department of Vertebrate Zoology, St. Petersburg State University, 199034 St. Petersburg, Russia
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6
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Granger J, Cummer SA, Lohmann KJ, Johnsen S. Environmental sources of radio frequency noise: potential impacts on magnetoreception. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:83-95. [DOI: 10.1007/s00359-021-01516-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 11/27/2022]
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7
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Broadband 75-85 MHz radiofrequency fields disrupt magnetic compass orientation in night-migratory songbirds consistent with a flavin-based radical pair magnetoreceptor. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:97-106. [PMID: 35019998 PMCID: PMC8918455 DOI: 10.1007/s00359-021-01537-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 12/15/2021] [Accepted: 12/17/2021] [Indexed: 12/20/2022]
Abstract
The light-dependent magnetic compass sense of night-migratory songbirds can be disrupted by weak radiofrequency fields. This finding supports a quantum mechanical, radical-pair-based mechanism of magnetoreception as observed for isolated cryptochrome 4, a protein found in birds’ retinas. The exact identity of the magnetically sensitive radicals in cryptochrome is uncertain in vivo, but their formation seems to require a bound flavin adenine dinucleotide chromophore and a chain of four tryptophan residues within the protein. Resulting from the hyperfine interactions of nuclear spins with the unpaired electrons, the sensitivity of the radicals to radiofrequency magnetic fields depends strongly on the number of magnetic nuclei (hydrogen and nitrogen atoms) they contain. Quantum-chemical calculations suggested that electromagnetic noise in the frequency range 75–85 MHz could give information about the identity of the radicals involved. Here, we show that broadband 75–85 MHz radiofrequency fields prevent a night-migratory songbird from using its magnetic compass in behavioural experiments. These results indicate that at least one of the components of the radical pair involved in the sensory process of avian magnetoreception must contain a substantial number of strong hyperfine interactions as would be the case if a flavin–tryptophan radical pair were the magnetic sensor.
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8
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Babcock N, Kattnig DR. Radical Scavenging Could Answer the Challenge Posed by Electron-Electron Dipolar Interactions in the Cryptochrome Compass Model. JACS AU 2021; 1:2033-2046. [PMID: 34841416 PMCID: PMC8611662 DOI: 10.1021/jacsau.1c00332] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Indexed: 06/13/2023]
Abstract
Many birds are endowed with a visual magnetic sense that may exploit magnetosensitive radical recombination processes in the protein cryptochrome. In this widely accepted but unproven model, geomagnetic sensitivity is suggested to arise from variations in the recombination rate of a pair of radicals, whose unpaired electron spins undergo coherent singlet-triplet interconversion in the geomagnetic field by coupling to nuclear spins via hyperfine interactions. However, simulations of this conventional radical pair mechanism (RPM) predicted only tiny magnetosensitivities for realistic conditions because the RPM's directional sensitivity is strongly suppressed by the intrinsic electron-electron dipolar (EED) interactions, casting doubt on its viability as a magnetic sensor. We show how this RPM-suppression problem is overcome in a three-radical system in which a third "scavenger" radical reacts with one member of the primary pair. We use this finding to predict substantial magnetic field effects that exceed those of the RPM in the presence of EED interactions in animal cryptochromes.
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Affiliation(s)
- Nathan
Sean Babcock
- Quantum
Biology Laboratory, Howard University, 2400 Sixth Street NW, Washington District of Columbia, 20059, United States of America
- 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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9
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Wiltschko R, Wiltschko W. The discovery of the use of magnetic navigational information. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:9-18. [PMID: 34476571 PMCID: PMC8918449 DOI: 10.1007/s00359-021-01507-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 12/01/2022]
Abstract
The magnetic field of the Earth provides animals with various kinds of information. Its use as a compass was discovered in the mid-1960s in birds, when it was first met with considerable skepticism, because it initially proved difficult to obtain evidence for magnetic sensitivity by conditioning experiments. Meanwhile, a magnetic compass was found to be widespread. It has now been demonstrated in members of all vertebrate classes, in mollusks and several arthropod species, in crustaceans as well as in insects. The use of the geomagnetic field as a ‘map’ for determining position, although already considered in the nineteenth century, was demonstrated by magnetically simulating displacements only after 2000, namely when animals, tested in the magnetic field of a distant site, responded as if they were physically displaced to that site and compensated for the displacement. Another use of the magnetic field is that as a ‘sign post’ or trigger: specific magnetic conditions elicit spontaneous responses that are helpful when animals reach the regions where these magnetic characteristics occur. Altogether, the geomagnetic field is a widely used valuable source of navigational information for mobile animals.
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Affiliation(s)
- Roswitha Wiltschko
- Fachbereich Biowissenschaften, Goethe-Universität Frankfurt, Max-von-Laue-Straße 13, 60438, Frankfurt am Main, Germany.
| | - Wolfgang Wiltschko
- Fachbereich Biowissenschaften, Goethe-Universität Frankfurt, Max-von-Laue-Straße 13, 60438, Frankfurt am Main, Germany
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10
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Wiltschko R, Nießner C, Wiltschko W. The Magnetic Compass of Birds: The Role of Cryptochrome. Front Physiol 2021; 12:667000. [PMID: 34093230 PMCID: PMC8171495 DOI: 10.3389/fphys.2021.667000] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/08/2021] [Indexed: 12/28/2022] Open
Abstract
The geomagnetic field provides directional information for birds. The avian magnetic compass is an inclination compass that uses not the polarity of the magnetic field but the axial course of the field lines and their inclination in space. It works in a flexible functional window, and it requires short-wavelength light. These characteristics result from the underlying sensory mechanism based on radical pair processes in the eyes, with cryptochrome suggested as the receptor molecule. The chromophore of cryptochrome, flavin adenine dinucleotide (FAD), undergoes a photocycle, where radical pairs are formed during photo-reduction as well as during re-oxidation; behavioral data indicate that the latter is crucial for detecting magnetic directions. Five types of cryptochromes are found in the retina of birds: cryptochrome 1a (Cry1a), cryptochrome 1b, cryptochrome 2, cryptochrome 4a, and cryptochrome 4b. Because of its location in the outer segments of the ultraviolet cones with their clear oil droplets, Cry1a appears to be the most likely receptor molecule for magnetic compass information.
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Affiliation(s)
- Roswitha Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Christine Nießner
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Wolfgang Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
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11
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Einwich A, Dedek K, Seth PK, Laubinger S, Mouritsen H. A novel isoform of cryptochrome 4 (Cry4b) is expressed in the retina of a night-migratory songbird. Sci Rep 2020; 10:15794. [PMID: 32978454 PMCID: PMC7519125 DOI: 10.1038/s41598-020-72579-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/28/2020] [Indexed: 01/22/2023] Open
Abstract
The primary sensory molecule underlying light-dependent magnetic compass orientation in migratory birds has still not been identified. The cryptochromes are the only known class of vertebrate proteins which could mediate this mechanism in the avian retina. Cryptochrome 4 of the night-migratory songbird the European robin (Erithacus rubecula; erCry4) has several of the properties needed to be the primary magnetoreceptor in the avian eye. Here, we report on the identification of a novel isoform of erCry4, which we named erCry4b. Cry4b includes an additional exon of 29 amino acids compared to the previously described form of Cry4, now called Cry4a. When comparing the retinal circadian mRNA expression pattern of the already known isoform erCry4a and the novel erCry4b isoform, we find that erCry4a is stably expressed throughout day and night, whereas erCry4b shows a diurnal mRNA oscillation. The differential characteristics of the two erCry4 isoforms regarding their 24-h rhythmicity in mRNA expression leads us to suggest that they might have different functions. Based on the 24-h expression pattern, erCry4a remains the more likely cryptochrome to be involved in radical-pair-based magnetoreception, but at the present time, an involvement of erCry4b cannot be excluded.
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Affiliation(s)
- Angelika Einwich
- Institute for Biology and Environmental Sciences, Neurosensorics/Animal Navigation, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany
| | - Karin Dedek
- Institute for Biology and Environmental Sciences, Neurosensorics/Animal Navigation, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany
| | - Pranav Kumar Seth
- Institute for Biology and Environmental Sciences, Neurosensorics/Animal Navigation, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany
| | - Sascha Laubinger
- Institute for Biology and Environmental Sciences, Evolutionäre Genetik der Pflanzen, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany
| | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, Neurosensorics/Animal Navigation, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany. .,Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Oldenburg, Germany.
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12
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Arabidopsis cryptochrome is responsive to Radiofrequency (RF) electromagnetic fields. Sci Rep 2020; 10:11260. [PMID: 32647192 PMCID: PMC7347919 DOI: 10.1038/s41598-020-67165-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 05/29/2020] [Indexed: 01/08/2023] Open
Abstract
How living systems respond to weak electromagnetic fields represents one of the major unsolved challenges in sensory biology. Recent evidence has implicated cryptochrome, an evolutionarily conserved flavoprotein receptor, in magnetic field responses of organisms ranging from plants to migratory birds. However, whether cryptochromes fulfill the criteria to function as biological magnetosensors remains to be established. Currently, theoretical predictions on the underlying mechanism of chemical magnetoreception have been supported by experimental observations that exposure to radiofrequency (RF) in the MHz range disrupt bird orientation and mammalian cellular respiration. Here we show that, in keeping with certain quantum physical hypotheses, a weak 7 MHz radiofrequency magnetic field significantly reduces the biological responsivity to blue light of the cryptochrome receptor cry1 in Arabidopsis seedlings. Using an in vivo phosphorylation assay that specifically detects activated cryptochrome, we demonstrate that RF exposure reduces conformational changes associated with biological activity. RF exposure furthermore alters cryptochrome-dependent plant growth responses and gene expression to a degree consistent with theoretical predictions. To our knowledge this represents the first demonstration of a biological receptor responding to RF exposure, providing important new implications for magnetosensing as well as possible future applications in biotechnology and medicine.
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13
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Chernetsov N, Pakhomov A, Davydov A, Cellarius F, Mouritsen H. No evidence for the use of magnetic declination for migratory navigation in two songbird species. PLoS One 2020; 15:e0232136. [PMID: 32330188 PMCID: PMC7182221 DOI: 10.1371/journal.pone.0232136] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/07/2020] [Indexed: 11/18/2022] Open
Abstract
Determining the East-West position was a classical problem in human sea navigation until accurate clocks were manufactured and sailors were able to measure the difference between local time and a fixed reference to determine longitude. Experienced night-migratory songbirds can correct for East-West physical and virtual magnetic displacements to unknown locations. Migratory birds do not appear to possess a time-different clock sense; therefore, they must solve the longitude problem in a different way. We showed earlier that experienced adult (but not juvenile) Eurasian reed warblers (Acrocephalus scirpaceus) can use magnetic declination (the difference in direction between geographic and magnetic North) to solve this problem when they were virtually displaced from Rybachy on the eastern Baltic coast to Scotland. In this study, we aimed to test how general this effect was. Adult and juvenile European robins (Erithacus rubecula) and adult garden warblers (Sylvia borin) under the same experimental conditions did not respond to this virtual magnetic displacement, suggesting significant variation in how navigational maps are organised in different songbird migrants.
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Affiliation(s)
- Nikita Chernetsov
- Biological Station Rybachy, Zoological Institute RAS, St. Petersburg, Russia
- Dept. Vertebrate Zoology, St. Petersburg State University, St. Petersburg, Russia
- * E-mail:
| | - Alexander Pakhomov
- Biological Station Rybachy, Zoological Institute RAS, St. Petersburg, Russia
| | - Alexander Davydov
- Biological Station Rybachy, Zoological Institute RAS, St. Petersburg, Russia
| | - Fedor Cellarius
- Dept. Vertebrate Zoology, Lomonosov Moscow State University, Moscow, Russia
| | - Henrik Mouritsen
- AG Neurosensory Sciences/Animal Navigation, Institut für Biologie und Umweltwissenschaften, Carl-von-Ossietzky Universität Oldenburg, Oldenburg, Germany
- Research Center for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
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14
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Bojarinova J, Kavokin K, Pakhomov A, Cherbunin R, Anashina A, Erokhina M, Ershova M, Chernetsov N. Magnetic compass of garden warblers is not affected by oscillating magnetic fields applied to their eyes. Sci Rep 2020; 10:3473. [PMID: 32103061 PMCID: PMC7044251 DOI: 10.1038/s41598-020-60383-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Accepted: 01/31/2020] [Indexed: 11/16/2022] Open
Abstract
The magnetic compass is an important element of the avian navigation system, which allows migratory birds to solve complex tasks of moving between distant breeding and wintering locations. The photochemical magnetoreception in the eye is believed to be the primary biophysical mechanism behind the magnetic sense of birds. It was shown previously that birds were disoriented in presence of weak oscillating magnetic fields (OMF) with frequencies in the megahertz range. The OMF effect was considered to be a fingerprint of the photochemical magnetoreception in the eye. In this work, we used miniaturized portable magnetic coils attached to the bird’s head to specifically target the compass receptor. We performed behavioural experiments on orientation of long-distance migrants, garden warblers (Sylvia borin), in round arenas. The OMF with the amplitude of about 5 nT was applied locally to the birds’ eyes. Surprisingly, the birds were not disoriented and showed the seasonally appropriate migratory direction. On the contrary, the same birds placed in a homogeneous 5 nT OMF generated by large stationary coils showed clear disorientation. On the basis of these findings, we suggest that the disruption of magnetic orientation of birds by oscillating magnetic fields is not related to photochemical magnetoreceptors in their eyes.
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Affiliation(s)
- Julia Bojarinova
- Department Vertebrate Zoology, St. Petersburg State University, 199034, St. Petersburg, Russia. .,Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223, St. Petersburg, Russia.
| | - Kirill Kavokin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223, St. Petersburg, Russia.,Spin Optics Lab., St. Petersburg State University, 198504, St. Petersburg, Russia
| | - Alexander Pakhomov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223, St. Petersburg, Russia.,Biological Station Rybachy, Zoological Institute of the Russian Academy of Sciences, 238535, Rybachy, Kaliningrad Region, Russia
| | - Roman Cherbunin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223, St. Petersburg, Russia.,Spin Optics Lab., St. Petersburg State University, 198504, St. Petersburg, Russia
| | - Anna Anashina
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223, St. Petersburg, Russia.,Biological Station Rybachy, Zoological Institute of the Russian Academy of Sciences, 238535, Rybachy, Kaliningrad Region, Russia
| | - Maria Erokhina
- Department Natural Science and Geography, Ilya Ulyanov State Pedagogical University, 432700, Ulyanovsk, Russia
| | - Maria Ershova
- Department Vertebrate Zoology, Lomonosov Moscow State University, 119234, Moscow, Russia
| | - Nikita Chernetsov
- Department Vertebrate Zoology, St. Petersburg State University, 199034, St. Petersburg, Russia.,Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223, St. Petersburg, Russia.,Biological Station Rybachy, Zoological Institute of the Russian Academy of Sciences, 238535, Rybachy, Kaliningrad Region, Russia
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15
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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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16
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Bartos P, Netusil R, Slaby P, Dolezel D, Ritz T, Vacha M. Weak radiofrequency fields affect the insect circadian clock. J R Soc Interface 2019; 16:20190285. [PMID: 31530135 DOI: 10.1098/rsif.2019.0285] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
It is known that the circadian clock in Drosophila can be sensitive to static magnetic fields (MFs). Man-made radiofrequency (RF) electromagnetic fields have been shown to have effects on animal orientation responses at remarkably weak intensities in the nanotesla range. Here, we tested if weak broadband RF fields also affect the circadian rhythm of the German cockroach (Blatella germanica). We observed that static MFs slow down the cockroach clock rhythm under dim UV light, consistent with results on the Drosophila circadian clock. Remarkably, 300 times weaker RF fields likewise slowed down the cockroach clock in a near-zero static magnetic field. This demonstrates that the internal clock of organisms can be sensitive to weak RF fields, consequently opening the possibility of an influence of man-made RF fields on many clock-dependent events in living systems.
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Affiliation(s)
- Premysl Bartos
- Department of Experimental Biology, Section of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Czech Republic
| | - Radek Netusil
- Department of Experimental Biology, Section of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Czech Republic
| | - Pavel Slaby
- Department of Experimental Biology, Section of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Czech Republic
| | - David Dolezel
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, Branisovska 31, Ceske Budejovice, Czech Republic.,Department of Molecular Biology and Genetics, Faculty of Science, Branisovska 31, Ceske Budejovice, Czech Republic
| | - Thorsten Ritz
- Department of Physics and Astronomy, University of California Irvine, Irvine, CA, USA
| | - Martin Vacha
- Department of Experimental Biology, Section of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Czech Republic
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17
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Abstract
Birds can use two kinds of information from the geomagnetic field for navigation: the direction of the field lines as a compass and probably magnetic intensity as a component of the navigational ‘map’. The direction of the magnetic field appears to be sensed via radical pair processes in the eyes, with the crucial radical pairs formed by cryptochrome. It is transmitted by the optic nerve to the brain, where parts of the visual system seem to process the respective information. Magnetic intensity appears to be perceived by magnetite-based receptors in the beak region; the information is transmitted by the ophthalmic branch of the trigeminal nerve to the trigeminal ganglion and the trigeminal brainstem nuclei. Yet in spite of considerable progress in recent years, many details are still unclear, among them details of the radical pair processes and their transformation into a nervous signal, the precise location of the magnetite-based receptors and the centres in the brain where magnetic information is combined with other navigational information for the navigational processes.
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Affiliation(s)
- Roswitha Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Wolfgang Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
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18
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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: 23] [Impact Index Per Article: 4.6] [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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19
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Nießner C, Denzau S, Peichl L, Wiltschko W, Wiltschko R. Magnetoreception: activation of avian cryptochrome 1a in various light conditions. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:977-984. [DOI: 10.1007/s00359-018-1296-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 07/26/2018] [Accepted: 09/26/2018] [Indexed: 12/24/2022]
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20
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Long-distance navigation and magnetoreception in migratory animals. Nature 2018; 558:50-59. [PMID: 29875486 DOI: 10.1038/s41586-018-0176-1] [Citation(s) in RCA: 223] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 04/13/2018] [Indexed: 11/08/2022]
Abstract
For centuries, humans have been fascinated by how migratory animals find their way over thousands of kilometres. Here, I review the mechanisms used in animal orientation and navigation with a particular focus on long-distance migrants and magnetoreception. I contend that any long-distance navigational task consists of three phases and that no single cue or mechanism will enable animals to navigate with pinpoint accuracy over thousands of kilometres. Multiscale and multisensory cue integration in the brain is needed. I conclude by raising twenty important mechanistic questions related to long-distance animal navigation that should be solved over the next twenty years.
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21
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Hiscock HG, Mouritsen H, Manolopoulos DE, Hore PJ. Disruption of Magnetic Compass Orientation in Migratory Birds by Radiofrequency Electromagnetic Fields. Biophys J 2017; 113:1475-1484. [PMID: 28978441 DOI: 10.1016/j.bpj.2017.07.031] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 07/19/2017] [Accepted: 07/31/2017] [Indexed: 11/30/2022] Open
Abstract
The radical-pair mechanism has been put forward as the basis of the magnetic compass sense of migratory birds. Some of the strongest supporting evidence has come from behavioral experiments in which birds exposed to weak time-dependent magnetic fields lose their ability to orient in the geomagnetic field. However, conflicting results and skepticism about the requirement for abnormally long quantum coherence lifetimes have cast a shroud of uncertainty over these potentially pivotal studies. Using a recently developed computational approach, we explore the effects of various radiofrequency magnetic fields on biologically plausible radicals within the theoretical framework of radical-pair magnetoreception. We conclude that the current model of radical-pair magnetoreception is unable to explain the findings of the reported behavioral experiments. Assuming that an unknown mechanism amplifies the predicted effects, we suggest experimental conditions that have the potential to distinguish convincingly between the two distinct families of radical pairs currently postulated as magnetic compass sensors. We end by making recommendations for experimental protocols that we hope will increase the chance that future experiments can be independently replicated.
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Affiliation(s)
- Hamish G Hiscock
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, Oxford, United Kingdom
| | - Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany; Research Centre for Neurosensory Sciences, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - David E Manolopoulos
- 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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22
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Kattnig DR. Radical-Pair-Based Magnetoreception Amplified by Radical Scavenging: Resilience to Spin Relaxation. J Phys Chem B 2017; 121:10215-10227. [DOI: 10.1021/acs.jpcb.7b07672] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- 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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23
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Wiltschko R, Ahmad M, Nießner C, Gehring D, Wiltschko W. Light-dependent magnetoreception in birds: the crucial step occurs in the dark. J R Soc Interface 2017; 13:rsif.2015.1010. [PMID: 27146685 PMCID: PMC4892254 DOI: 10.1098/rsif.2015.1010] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 04/12/2016] [Indexed: 11/24/2022] Open
Abstract
The Radical Pair Model proposes that the avian magnetic compass is based on spin-chemical processes: since the ratio between the two spin states singlet and triplet of radical pairs depends on their alignment in the magnetic field, it can provide information on magnetic directions. Cryptochromes, blue light-absorbing flavoproteins, with flavin adenine dinucleotide as chromophore, are suggested as molecules forming the radical pairs underlying magnetoreception. When activated by light, cryptochromes undergo a redox cycle, in the course of which radical pairs are generated during photo-reduction as well as during light-independent re-oxidation. This raised the question as to which radical pair is crucial for mediating magnetic directions. Here, we present the results from behavioural experiments with intermittent light and magnetic field pulses that clearly show that magnetoreception is possible in the dark interval, pointing to the radical pair formed during flavin re-oxidation. This differs from the mechanism considered for cryptochrome signalling the presence of light and rules out most current models of an avian magnetic compass based on the radical pair generated during photo-reduction. Using the radical pair formed during re-oxidation may represent a specific adaptation of the avian magnetic compass.
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Affiliation(s)
- Roswitha Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany
| | - Margaret Ahmad
- Université Pierre et Marie Curie, Casier 156, 4 Place Jussieu, 75005 Paris, France
| | - Christine Nießner
- FB Biowissenschaften, Goethe-Universität Frankfurt, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany
| | - Dennis Gehring
- FB Biowissenschaften, Goethe-Universität Frankfurt, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany
| | - Wolfgang Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Max-von-Laue-Straße 13, 60438 Frankfurt am Main, Germany
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24
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Pakhomov A, Bojarinova J, Cherbunin R, Chetverikova R, Grigoryev PS, Kavokin K, Kobylkov D, Lubkovskaja R, Chernetsov N. Very weak oscillating magnetic field disrupts the magnetic compass of songbird migrants. J R Soc Interface 2017; 14:20170364. [PMID: 28794163 PMCID: PMC5582129 DOI: 10.1098/rsif.2017.0364] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/13/2017] [Indexed: 11/12/2022] Open
Abstract
Previously, it has been shown that long-distance migrants, garden warblers (Sylvia borin), were disoriented in the presence of narrow-band oscillating magnetic field (1.403 MHz OMF, 190 nT) during autumn migration. This agrees with the data of previous experiments with European robins (Erithacus rubecula). In this study, we report the results of experiments with garden warblers tested under a 1.403 MHz OMF with various amplitudes (∼0.4, 1, ∼2.4, 7 and 20 nT). We found that the ability of garden warblers to orient in round arenas using the magnetic compass could be disrupted by a very weak oscillating field, such as an approximate 2.4, 7 and 20 nT OMF, but not by an OMF with an approximate 0.4 nT amplitude. The results of the present study indicate that the sensitivity threshold of the magnetic compass to the OMF lies around 2-3 nT, while in experiments with European robins the birds were disoriented in a 15 nT OMF but could choose the appropriate migratory direction when a 5 nT OMF was added to the stationary magnetic field. The radical-pair model, one of the mainstream theories of avian magnetoreception, cannot explain the sensitivity to such a low-intensity OMF, and therefore, it needs further refinement.
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Affiliation(s)
- Alexander Pakhomov
- Biological Station Rybachy, Zoological Institute RAS, 238535 Rybachy, Kaliningrad Region, Russia
- Sechenov Institute of Evolutionary Physiology and Biochemistry, 44 Thorez Ave, 194223 St Petersburg, Russia
| | - Julia Bojarinova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, 44 Thorez Ave, 194223 St Petersburg, Russia
- St Petersburg State University, 7-9 Universitetskaya Emb., St Petersburg 199034, Russia
| | - Roman Cherbunin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, 44 Thorez Ave, 194223 St Petersburg, Russia
- St Petersburg State University, 7-9 Universitetskaya Emb., St Petersburg 199034, Russia
| | - Raisa Chetverikova
- St Petersburg State University, 7-9 Universitetskaya Emb., St Petersburg 199034, Russia
- AG Neurosensorik (Animal Navigation), Institut für Biologie und Umweltwissenschaften (IBU), University of Oldenburg, 26111 Oldenburg, Germany
| | - Philipp S Grigoryev
- St Petersburg State University, 7-9 Universitetskaya Emb., St Petersburg 199034, Russia
| | - Kirill Kavokin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, 44 Thorez Ave, 194223 St Petersburg, Russia
- St Petersburg State University, 7-9 Universitetskaya Emb., St Petersburg 199034, Russia
- A.F. Ioffe Physical Technical Institute, 26 Polytechnicheskaya, St Petersburg 194021, Russia
| | - Dmitry Kobylkov
- AG Neurosensorik (Animal Navigation), Institut für Biologie und Umweltwissenschaften (IBU), University of Oldenburg, 26111 Oldenburg, Germany
| | - Regina Lubkovskaja
- St Petersburg State University, 7-9 Universitetskaya Emb., St Petersburg 199034, Russia
| | - Nikita Chernetsov
- Biological Station Rybachy, Zoological Institute RAS, 238535 Rybachy, Kaliningrad Region, Russia
- Sechenov Institute of Evolutionary Physiology and Biochemistry, 44 Thorez Ave, 194223 St Petersburg, Russia
- St Petersburg State University, 7-9 Universitetskaya Emb., St Petersburg 199034, Russia
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25
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Nießner C, Winklhofer M. Radical-pair-based magnetoreception in birds: radio-frequency experiments and the role of cryptochrome. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:499-507. [PMID: 28612234 PMCID: PMC5522499 DOI: 10.1007/s00359-017-1189-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/28/2017] [Accepted: 05/29/2017] [Indexed: 11/30/2022]
Abstract
The radical-pair hypothesis of magnetoreception has gained a lot of momentum, since the flavoprotein cryptochrome was postulated as a structural candidate to host magnetically sensitive chemical reactions. Here, we first discuss behavioral tests using radio-frequency magnetic fields (0.1-10 MHz) to specifically disturb a radical-pair-based avian magnetic compass sense. While disorienting effects of broadband RF magnetic fields have been replicated independently in two competing labs, the effects of monochromatic RF magnetic fields administered at the electronic Larmor frequency (~1.3 MHz) are disparate. We give technical recommendations for future RF experiments. We then focus on two candidate magnetoreceptor proteins in birds, Cry1a and Cry1b, two splice variants of the same gene (Cry1). Immunohistochemical studies have identified Cry1a in the outer segments of the ultraviolet/violet-sensitive cone photoreceptors and Cry1b in the cytosol of retinal ganglion cells. The identification of the host neurons of these cryptochromes and their subcellular expression patterns presents an important advance, but much work lies ahead to gain some functional understanding. In particular, interaction partners of cryptochrome Cry1a and Cry1b remain to be identified. A candidate partner for Cry4 was previously suggested, but awaits independent replication.
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Affiliation(s)
- Christine Nießner
- Ernst Strüngmann Institute for Neuroscience, Deutschordenstr 46, 60528, Frankfurt am Main, Germany
| | - Michael Winklhofer
- Institute for Biology and Environmental Sciences IBU, School of Mathematics and Science, University of Oldenburg, 26111, Oldenburg, Germany.
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26
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Lateralization of the Avian Magnetic Compass: Analysis of Its Early Plasticity. Symmetry (Basel) 2017. [DOI: 10.3390/sym9050077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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27
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Kavokin K. Can a hybrid chemical-ferromagnetic model of the avian compass explain its outstanding sensitivity to magnetic noise? PLoS One 2017; 12:e0173887. [PMID: 28296939 PMCID: PMC5352016 DOI: 10.1371/journal.pone.0173887] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 02/28/2017] [Indexed: 11/30/2022] Open
Abstract
While many properties of the magnetic compass of migratory birds are satisfactory explained within the chemical model of magnetoreception, its extreme sensitivity to radio-frequency magnetic fields remains a mystery. Apparently, this difficulty could be overcome if the magnetoreceptor model were augmented with a magnetite nanoparticle, which would amplify the magnetic field at the position of the magneto-sensitive cryptochrome molecule. However, comparison of the radio-frequency power used in the experiment with intrinsic magnetization noise of such a particle, estimated from the theory of fluctuations, shows that the required sensitivity cannot be reached with realistic parameters of iron-oxide nanocrystals.
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Affiliation(s)
- Kirill Kavokin
- Spin Optics Laboratory, St. Petersburg State University, St. Petersburg, Russia
- I.M.Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, St. Petersburg, Russia
- * E-mail:
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28
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29
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Compass systems. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:447-453. [DOI: 10.1007/s00359-016-1140-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/04/2016] [Accepted: 12/12/2016] [Indexed: 11/26/2022]
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30
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Hiscock HG, Kattnig DR, Manolopoulos DE, Hore PJ. Floquet theory of radical pairs in radiofrequency magnetic fields. J Chem Phys 2016; 145:124117. [DOI: 10.1063/1.4963793] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- Hamish G. Hiscock
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Daniel R. Kattnig
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - David E. Manolopoulos
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - P. J. Hore
- Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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31
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Affiliation(s)
- P. J. Hore
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität Oldenburg, DE-26111 Oldenburg, Germany;
- Research Centre for Neurosensory Sciences, University of Oldenburg, DE-26111 Oldenburg, Germany
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32
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Schwarze S, Schneider NL, Reichl T, Dreyer D, Lefeldt N, Engels S, Baker N, Hore PJ, Mouritsen H. Weak Broadband Electromagnetic Fields are More Disruptive to Magnetic Compass Orientation in a Night-Migratory Songbird (Erithacus rubecula) than Strong Narrow-Band Fields. Front Behav Neurosci 2016; 10:55. [PMID: 27047356 PMCID: PMC4801848 DOI: 10.3389/fnbeh.2016.00055] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 03/07/2016] [Indexed: 11/13/2022] Open
Abstract
Magnetic compass orientation in night-migratory songbirds is embedded in the visual system and seems to be based on a light-dependent radical pair mechanism. Recent findings suggest that both broadband electromagnetic fields ranging from ~2 kHz to ~9 MHz and narrow-band fields at the so-called Larmor frequency for a free electron in the Earth's magnetic field can disrupt this mechanism. However, due to local magnetic fields generated by nuclear spins, effects specific to the Larmor frequency are difficult to understand considering that the primary sensory molecule should be organic and probably a protein. We therefore constructed a purpose-built laboratory and tested the orientation capabilities of European robins in an electromagnetically silent environment, under the specific influence of four different oscillating narrow-band electromagnetic fields, at the Larmor frequency, double the Larmor frequency, 1.315 MHz or 50 Hz, and in the presence of broadband electromagnetic noise covering the range from ~2 kHz to ~9 MHz. Our results indicated that the magnetic compass orientation of European robins could not be disrupted by any of the relatively strong narrow-band electromagnetic fields employed here, but that the weak broadband field very efficiently disrupted their orientation.
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Affiliation(s)
- Susanne Schwarze
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - Nils-Lasse Schneider
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - Thomas Reichl
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - David Dreyer
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - Nele Lefeldt
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - Svenja Engels
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - Neville Baker
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry LaboratoryOxford, UK
| | - P. J. Hore
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry LaboratoryOxford, UK
| | - Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
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33
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Tomanova K, Vacha M. The magnetic orientation of the Antarctic amphipod Gondogeneia antarctica is cancelled by very weak radiofrequency fields. J Exp Biol 2016; 219:1717-24. [DOI: 10.1242/jeb.132878] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 03/15/2016] [Indexed: 11/20/2022]
Abstract
Studies on weak man-made radiofrequency electromagnetic fields (RF) affecting animal magnetoreception aim for a better understanding of the reception mechanism and also point to a new phenomenon having possible consequences in ecology and environmental protection. RF impacts on magnetic compasses have recently been demonstrated on migratory birds and other vertebrates. We set out to investigate the effect of RF on the magnetic orientation of the Antarctic krill species Gondogeneia antarctica, a small marine crustacean widespread along the Antarctic littoral line. Here, we show that having been released under laboratory conditions, G. antarctica escaped in the magnetically seaward direction along the magnetic sea-land axis (Y-axis) of the home beach. However, the animals were disoriented after being exposed to RF. Orientation was lost not only in an RF of a magnetic flux density of 20 nT, as expected according to the literary data, but even under the 2 nT originally intended as a control. Our results extend recent findings of the extraordinary sensitivity of animal magnetoreception to weak RF fields in marine invertebrates.
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Affiliation(s)
- K. Tomanova
- Department of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Brno, Kamenice 735/5, 625 00 Brno, Czech Republic
| | - M. Vacha
- Department of Animal Physiology and Immunology, Faculty of Science, Masaryk University, Brno, Kamenice 735/5, 625 00 Brno, Czech Republic
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34
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Wiltschko R, Thalau P, Gehring D, Nießner C, Ritz T, Wiltschko W. Magnetoreception in birds: the effect of radio-frequency fields. J R Soc Interface 2015; 12:rsif.2014.1103. [PMID: 25540238 DOI: 10.1098/rsif.2014.1103] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The avian magnetic compass, probably based on radical pair processes, works only in a narrow functional window around the local field strength, with cryptochrome 1a as most likely receptor molecule. Radio-frequency fields in the MHz range have been shown to disrupt the birds' orientation, yet the nature of this interference is still unclear. In an immuno-histological study, we tested whether the radio-frequency fields interfere with the photoreduction of cryptochrome, but this does not seem to be the case. In behavioural studies, birds were not able to adjust to radio-frequency fields like they are able to adjust to static fields outside the normal functional range: neither a 2-h pre-exposure in a 7.0 MHz field, 480 nT, nor a 7-h pre-exposure in a 1.315 MHz field, 15 nT, allowed the birds to regain their orientation ability. This inability to adjust to radio-frequency fields suggests that these fields interfere directly with the primary processes of magnetoreception and therefore disable the avian compass as long as they are present. They do not have lasting adverse after-effects, however, as birds immediately after exposure to a radio-frequency field were able to orient in the local geomagnetic field.
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Affiliation(s)
- Roswitha Wiltschko
- FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany
| | - Peter Thalau
- FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany
| | - Dennis Gehring
- FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany
| | - Christine Nießner
- FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany
| | - Thorsten Ritz
- Department of Physics and Astronomy, University of California, Irvine, CA 92697-4575, USA
| | - Wolfgang Wiltschko
- FB Biowissenschaften, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany
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Wiltschko R, Wiltschko W. Avian Navigation: A Combination of Innate and Learned Mechanisms. ADVANCES IN THE STUDY OF BEHAVIOR 2015. [DOI: 10.1016/bs.asb.2014.12.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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