A Putative Mechanism for Magnetoreception by Electromagnetic Induction in the Pigeon Inner Ear

Nimpf, Simon; Nordmann, Grégory; Kagerbauer, Daniel; Malkemper, E. Pascal; Landler, Lukas; Papadaki-Anastasopoulou, Artemis; Ushakova, Lyubov; Wenninger-Weinzierl, Andrea; Novatchkova, Maria; Vincent, Peter; Lendl, Thomas; Colombini, Martin; Mason, Matthew J.; Keays, David A.

doi:10.1016/j.cub.2019.09.048

Cited by 66 publications

(54 citation statements)

References 38 publications

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“…Given the absence of clCRY4 homologs in mammals, it is conceivable that other light-sensitive molecules exist that may function as magnetic sensors. It is also important to emphasize that our results do not exclude the presence of complementary light-independent mechanisms that rely on magnetite or alternatively electromagnetic induction ( 45 ). Despite these caveats, our data support a model whereby clCRY4 acts as a UV-blue photoreceptor and/or a light-dependent magnetosensor by modulating glutamatergic synapses between horizontal cells and cones ( Fig.…”

Section: Discussioncontrasting

confidence: 72%

The biophysical, molecular, and anatomical landscape of pigeon CRY4: A candidate light-based quantal magnetosensor

et al. 2020

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The biophysical and molecular mechanisms that enable animals to detect magnetic fields are unknown. It has been proposed that birds have a light-dependent magnetic compass that relies on the formation of radical pairs within cryptochrome molecules. Using spectroscopic methods, we show that pigeon cryptochrome clCRY4 is photoreduced efficiently and forms long-lived spin-correlated radical pairs via a tetrad of tryptophan residues. We report that clCRY4 is broadly and stably expressed within the retina but enriched at synapses in the outer plexiform layer in a repetitive manner. A proteomic survey for retinal-specific clCRY4 interactors identified molecules that are involved in receptor signaling, including glutamate receptor–interacting protein 2, which colocalizes with clCRY4. Our data support a model whereby clCRY4 acts as an ultraviolet-blue photoreceptor and/or a light-dependent magnetosensor by modulating glutamatergic synapses between horizontal cells and cones.

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Section: Discussioncontrasting

confidence: 72%

The biophysical, molecular, and anatomical landscape of pigeon CRY4: A candidate light-based quantal magnetosensor

et al. 2020

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“…Another mechanism based on electromagnetic induction has been acknowledged as the basis of magnetoreception for some marine animals, such as sharks [Kalmijn, 1981], but mostly discarded for land animals. However, recently Nimpf et al [2019] proposed that electromagnetic induction can be the biophysical mechanism involved in magnetoreception of pigeons through the generation of voltages in the semicircular canals of the inner ear. Our results are consistent with those mechanisms because the sensitivity to the magnetic inclination is related to the distribution of cryptochrome chromophores in a spherical eye, creating an inhomogeneous distribution of radical pairs as a function of the angular position on the eye relative to the magnetic field direction.…”

Section: Discussionmentioning

confidence: 99%

Magnetosensitivity in the Stingless Bee Tetragonisca angustula: Magnetic Inclination Can Alter the Choice of the Flying Departure Angle From the Nest

Vale

Acosta‐Avalos

2020

Bioelectromagnetics

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It is known that animals are sensitive to the geomagnetic field. In the case of insects, magnetoreception has been reported in several ant species and in some bees and wasps. One study showed that the stingless bee Tetragonisca angustula is able to sense the modification of the magnetic field inclination. The aim of the present manuscript is to continue that study in T. angustula, analyzing the nest arrival and departure angles in the presence of magnetic fields generated by magnets. The bees flying to and from the nest were recorded and the flying trajectories were obtained by analyzing the video frame by frame. The magnetic field was generated by 6, 9, or 12 magnets contained inside an Eppendorf tube and fixed near the nest. Our results show that T. angustula bees are sensitive to magnetic fields because the departure angles are influenced by the magnets. It was observed that these bees are sensitive to the polarization of the magnetic field vector that influences the choice of flying up or down, and this sensitivity has a window until about 80 μT (about four times the local geomagnetic field), with the magnetic field information for higher magnetic field intensities being ignored by the bees.

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“…We fitted turtles in the experimental group with a neodymium magnet (K&J Magnetics, Inc., Pipersville, PA; D41‐N52; 0.38 g; 6.35 mm diameter, 1.59 mm thickness; surface field: 3,309 Gauss, Br max = 14,900 Gauss; Bh max = 52 MGOe) attached to the leading edge of the nuchal scale of the carapace (following Congdon et al., 2015). Placement of the magnets on the carapace—a fixed, rigid mineralized tissue—with epoxy assured that the positions of the magnets did not change throughout the animal's migration and was uniform across all animals in the study, thereby preventing magnet positional changes (Nimpf et al., 2019). Although the exact nature of disruption to the magnetic field can be complex, given that the magnets used were 500–1000 times greater than the strength of the Earth's magnetic field at the surface (range 0.3–0.6 Gauss) and as the magnets were < 5 cm from the center of the turtle's head, we can confidentially say that immediate magnetic field around the head of turtles was disrupted.…”

Section: Methodsmentioning

confidence: 99%

The geomagnetic field does not appear to influence navigation in Eastern painted turtles

2020

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Geomagnetic cues provide important information to guide aspects of migration, from the general direction of movement to informing an animal's specific location on the planet. Although such cues are used by many long‐distant migrants, its use for short‐ and moderate‐distance migrations is less clear. We have been studying overland migratory movements in a population of Eastern painted turtles where animals use one of four precise, highly predictable routes to locate water sources during migration. Our previous work suggests a strong role of learning and spatial memory in this precise navigation, but the cues used and the context for their use are unknown. Here, we present a series of controlled field experiments in which we test the hypothesis that geomagnetic cues are utilized when Chrysemys picta engage in these intricate, overland movements. We fitted turtles with 3,309 Gauss magnets (n = 10) or aluminum disk controls (n = 5) and surveyed their ability to locate and navigate their routes during migration; turtles were similarly tested for these abilities outside of the context of migration (magnets, n = 30; control, n = 30). Strong magnets (3,309 Gauss) on their carapaces did not disrupt turtles’ ability to locate the paths or the precision with which they navigated them. Turtles, irrespective of treatment, found their paths and/or navigated their paths with the same high precision that we observed in controls and our previous work, both within and outside of the context of migration. Thus, alternative types of cues must be in use that explain the high precision and high reliability of path location over time. Future studies should examine alternative cues used in migratory navigation and the creation of complex and specific paths.

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A Putative Mechanism for Magnetoreception by Electromagnetic Induction in the Pigeon Inner Ear

Cited by 66 publications

References 38 publications

The biophysical, molecular, and anatomical landscape of pigeon CRY4: A candidate light-based quantal magnetosensor

The biophysical, molecular, and anatomical landscape of pigeon CRY4: A candidate light-based quantal magnetosensor

Magnetosensitivity in the Stingless Bee Tetragonisca angustula: Magnetic Inclination Can Alter the Choice of the Flying Departure Angle From the Nest

The geomagnetic field does not appear to influence navigation in Eastern painted turtles

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