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Ernst DA, Fitak RR, Schmidt M, Derby CD, Johnsen S, Lohmann KJ. Pulse magnetization elicits differential gene expression in the central nervous system of the Caribbean spiny lobster, Panulirus argus. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:725-742. [PMID: 32607762 DOI: 10.1007/s00359-020-01433-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 05/18/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022]
Abstract
Diverse animals use Earth's magnetic field to guide their movements, but the neural and molecular mechanisms underlying the magnetic sense remain enigmatic. One hypothesis is that particles of the mineral magnetite (Fe3O4) provide the basis of magnetoreception. Here we examined gene expression in the central nervous system of a magnetically sensitive invertebrate, the Caribbean spiny lobster (Panulirus argus), after applying a magnetic pulse known to alter magnetic orientation behavior. Numerous genes were differentially expressed in response to the pulse, including 647 in the brain, 1256 in the subesophageal ganglion, and 712 in the thoracic ganglia. Many such genes encode proteins linked to iron regulation, oxidative stress, and immune response, consistent with possible impacts of a magnetic pulse on magnetite-based magnetoreceptors. Additionally, however, altered expression also occurred for numerous genes with no apparent link to magnetoreception, including genes encoding proteins linked to photoreception, carbohydrate and hormone metabolism, and other physiological processes. Overall, the results are consistent with the magnetite hypothesis of magnetoreception, yet also reveal that in spiny lobsters, a strong pulse altered expression of > 10% of all expressed genes, including many seemingly unrelated to sensory processes. Thus, caution is required when interpreting the effects of magnetic pulses on animal behavior.
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Affiliation(s)
- David A Ernst
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA. .,Department of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701, USA.
| | - Robert R Fitak
- Genomics and Bioinformatics Cluster, Department of Biology, University of Central Florida, Orlando, FL, 32816, USA
| | - Manfred Schmidt
- Neuroscience Institute and Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - Charles D Derby
- Neuroscience Institute and Department of Biology, Georgia State University, Atlanta, GA, 30303, USA
| | - Sönke Johnsen
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - Kenneth J Lohmann
- Department of Biology, University of North Carolina, Chapel Hill, NC, 27599, USA
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Fitak RR, Schweikert LE, Wheeler BR, Ernst DA, Lohmann KJ, Johnsen S. Near absence of differential gene expression in the retina of rainbow trout after exposure to a magnetic pulse: implications for magnetoreception. Biol Lett 2018; 14:rsbl.2018.0209. [PMID: 29875210 DOI: 10.1098/rsbl.2018.0209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 05/08/2018] [Indexed: 12/19/2022] Open
Abstract
The ability to perceive the Earth's magnetic field, or magnetoreception, exists in numerous animals. Although the mechanism underlying magnetoreception has not been clearly established in any species, in salmonid fish, it is hypothesized to occur by means of crystals of magnetite associated with nervous tissue such as the brain, olfactory organ or retina. In this study, rainbow trout (Oncorhynchus mykiss) were exposed to a brief magnetic pulse known to disrupt magnetic orientation behaviour in several animals. Changes in gene expression induced by the pulse were then examined in the retina. Analyses indicated that the pulse elicited differential expression of only a single gene, gamma-crystallin M3-like (crygm3). The near absence of an effect of the magnetic pulse on gene expression in the retina stands in sharp contrast to a recent study in which 181 genes were differentially expressed in brain tissue of O. mykiss after exposure to the same pulse. Overall, our results suggest either that magnetite-based magnetoreceptors in trout are not located in the retina, or else that they are unaffected by magnetic pulses that can disrupt magnetic orientation behaviour in animals.
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Affiliation(s)
- Robert R Fitak
- Department of Biology, Duke University, Durham, NC 27708, USA
| | | | | | - David A Ernst
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Kenneth J Lohmann
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Sönke Johnsen
- Department of Biology, Duke University, Durham, NC 27708, USA
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