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Birchard K, Driver HG, Ademidun D, Bedolla-Guzmán Y, Birt T, Chown EE, Deane P, Harkness BAS, Morrin A, Masello JF, Taylor RS, Friesen VL. Circadian gene variation in relation to breeding season and latitude in allochronic populations of two pelagic seabird species complexes. Sci Rep 2023; 13:13692. [PMID: 37608061 PMCID: PMC10444859 DOI: 10.1038/s41598-023-40702-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 08/16/2023] [Indexed: 08/24/2023] Open
Abstract
Annual cues in the environment result in physiological changes that allow organisms to time reproduction during periods of optimal resource availability. Understanding how circadian rhythm genes sense these environmental cues and stimulate the appropriate physiological changes in response is important for determining the adaptability of species, especially in the advent of changing climate. A first step involves characterizing the environmental correlates of natural variation in these genes. Band-rumped and Leach's storm-petrels (Hydrobates spp.) are pelagic seabirds that breed across a wide range of latitudes. Importantly, some populations have undergone allochronic divergence, in which sympatric populations use the same breeding sites at different times of year. We investigated the relationship between variation in key functional regions of four genes that play an integral role in the cellular clock mechanism-Clock, Bmal1, Cry2 and Per2-with both breeding season and absolute latitude in these two species complexes. We discovered that allele frequencies in two genes, Clock and Bmal1, differed between seasonal populations in one archipelago, and also correlated with absolute latitude of breeding colonies. These results indicate that variation in these circadian rhythm genes may be involved in allochronic speciation, as well as adaptation to photoperiod at breeding locations.
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Affiliation(s)
- Katie Birchard
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
- Apex Resource Management Solutions, Ottawa, ON, K2A 3K2, Canada
| | - Hannah G Driver
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, K1H 8L1, Canada
| | - Dami Ademidun
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
| | | | - Tim Birt
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Erin E Chown
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Petra Deane
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
- Mascoma LLC, Lallemand Inc., Lebanon, NH, 03766, USA
| | - Bronwyn A S Harkness
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
- Environment and Climate Change Canada, Wildlife Research Division, Ottawa, ON, K1S 5B6, Canada
| | - Austin Morrin
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
- Sims Animal Hospital, Kingston, ON, K7K 7E9, Canada
| | - Juan F Masello
- Department of Animal Behaviour, University of Bielefeld, 33615, Bielefeld, Germany
| | - Rebecca S Taylor
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada
- Environment and Climate Change Canada, Landscape Science and Technology Division, Ottawa, ON, K1S 5R1, Canada
| | - Vicki L Friesen
- Biology Department, Queen's University, Kingston, ON, K7L 3N6, Canada.
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2
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Bhoi JD, Goel M, Ribelayga CP, Mangel SC. Circadian clock organization in the retina: From clock components to rod and cone pathways and visual function. Prog Retin Eye Res 2023; 94:101119. [PMID: 36503722 PMCID: PMC10164718 DOI: 10.1016/j.preteyeres.2022.101119] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 08/22/2022] [Accepted: 08/25/2022] [Indexed: 12/13/2022]
Abstract
Circadian (24-h) clocks are cell-autonomous biological oscillators that orchestrate many aspects of our physiology on a daily basis. Numerous circadian rhythms in mammalian and non-mammalian retinas have been observed and the presence of an endogenous circadian clock has been demonstrated. However, how the clock and associated rhythms assemble into pathways that support and control retina function remains largely unknown. Our goal here is to review the current status of our knowledge and evaluate recent advances. We describe many previously-observed retinal rhythms, including circadian rhythms of morphology, biochemistry, physiology, and gene expression. We evaluate evidence concerning the location and molecular machinery of the retinal circadian clock, as well as consider findings that suggest the presence of multiple clocks. Our primary focus though is to describe in depth circadian rhythms in the light responses of retinal neurons with an emphasis on clock control of rod and cone pathways. We examine evidence that specific biochemical mechanisms produce these daily light response changes. We also discuss evidence for the presence of multiple circadian retinal pathways involving rhythms in neurotransmitter activity, transmitter receptors, metabolism, and pH. We focus on distinct actions of two dopamine receptor systems in the outer retina, a dopamine D4 receptor system that mediates circadian control of rod/cone gap junction coupling and a dopamine D1 receptor system that mediates non-circadian, light/dark adaptive regulation of gap junction coupling between horizontal cells. Finally, we evaluate the role of circadian rhythmicity in retinal degeneration and suggest future directions for the field of retinal circadian biology.
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Affiliation(s)
- Jacob D Bhoi
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, UTHEALTH-The University of Texas Health Science Center at Houston, Houston, TX, USA; Neuroscience Honors Research Program, William Marsh Rice University, Houston, TX, USA
| | - Manvi Goel
- Department of Neuroscience, Wexner Medical Center, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Christophe P Ribelayga
- Ruiz Department of Ophthalmology and Visual Science, McGovern Medical School, UTHEALTH-The University of Texas Health Science Center at Houston, Houston, TX, USA; Neuroscience Honors Research Program, William Marsh Rice University, Houston, TX, USA.
| | - Stuart C Mangel
- Department of Neuroscience, Wexner Medical Center, College of Medicine, The Ohio State University, Columbus, OH, USA.
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3
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Einwich A, Seth PK, Bartölke R, Bolte P, Feederle R, Dedek K, Mouritsen H. Localisation of cryptochrome 2 in the avian retina. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:69-81. [PMID: 34677638 PMCID: PMC8918457 DOI: 10.1007/s00359-021-01506-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022]
Abstract
Cryptochromes are photolyase-related blue-light receptors acting as core components of the mammalian circadian clock in the cell nuclei. One or more members of the cryptochrome protein family are also assumed to play a role in avian magnetoreception, but the primary sensory molecule in the retina of migratory birds that mediates light-dependent magnetic compass orientation has still not been identified. The mRNA of cryptochrome 2 (Cry2) has been reported to be located in the cell nuclei of the retina, but Cry2 localisation has not yet been demonstrated at the protein level. Here, we provide evidence that Cry2 protein is located in the photoreceptor inner segments, the outer nuclear layer, the inner nuclear layer and the ganglion cell layer in the retina of night-migratory European robins, homing pigeons and domestic chickens. At the subcellular level, we find Cry2 both in the cytoplasm and the nucleus of cells residing in these layers. This broad nucleic expression rather points to a role for avian Cry2 in the circadian clock and is consistent with a function as a transcription factor, analogous to mammalian Cry2, and speaks against an involvement in magnetoreception.
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Affiliation(s)
- Angelika Einwich
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Pranav Kumar Seth
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Rabea Bartölke
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Petra Bolte
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Regina Feederle
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute for Diabetes and Obesity, Monoclonal Antibody Core Facility, Neuherberg, Germany
| | - Karin Dedek
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany. .,Research Centre for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.
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4
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Balay SD, Hochstoeger T, Vilceanu A, Malkemper EP, Snider W, Dürnberger G, Mechtler K, Schuechner S, Ogris E, Nordmann GC, Ushakova L, Nimpf S, Keays DA. The expression, localisation and interactome of pigeon CRY2. Sci Rep 2021; 11:20293. [PMID: 34645873 PMCID: PMC8514597 DOI: 10.1038/s41598-021-99207-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/13/2021] [Indexed: 11/18/2022] Open
Abstract
Cryptochromes (CRY) are highly conserved signalling molecules that regulate circadian rhythms and are candidate radical pair based magnetoreceptors. Birds have at least four cryptochromes (CRY1a, CRY1b, CRY2, and CRY4), but few studies have interrogated their function. Here we investigate the expression, localisation and interactome of clCRY2 in the pigeon retina. We report that clCRY2 has two distinct transcript variants, clCRY2a, and a previously unreported splice isoform, clCRY2b which is larger in size. We show that clCRY2a mRNA is expressed in all retinal layers and clCRY2b is enriched in the inner and outer nuclear layer. To define the localisation and interaction network of clCRY2 we generated and validated a monoclonal antibody that detects both clCRY2 isoforms. Immunohistochemical studies revealed that clCRY2a/b is present in all retinal layers and is enriched in the outer limiting membrane and outer plexiform layer. Proteomic analysis showed clCRY2a/b interacts with typical circadian molecules (PER2, CLOCK, ARTNL), cell junction proteins (CTNNA1, CTNNA2) and components associated with the microtubule motor dynein (DYNC1LI2, DCTN1, DCTN2, DCTN3) within the retina. Collectively these data show that clCRY2 is a component of the avian circadian clock and unexpectedly associates with the microtubule cytoskeleton.
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Affiliation(s)
- Spencer D Balay
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria.,Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030, Vienna, Austria
| | - Tobias Hochstoeger
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria
| | - Alexandra Vilceanu
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria
| | - E Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Center of Advanced European Studies and Research (Caesar), Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
| | - William Snider
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Gerhard Dürnberger
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria.,Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Karl Mechtler
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria.,Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Stefan Schuechner
- Monoclonal Antibody Facility, Max Perutz Labs, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Egon Ogris
- Monoclonal Antibody Facility, Max Perutz Labs, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Gregory C Nordmann
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria.,Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, 1030, Vienna, Austria
| | - Lyubov Ushakova
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria
| | - Simon Nimpf
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria
| | - David A Keays
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, 1030, Vienna, Austria. .,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Australia. .,Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University Munich, Planegg-Martinsried, 82152, Munich, Germany.
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5
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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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6
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Saha S, Singh KM, Gupta BBP. Robust circadian and circannual rhythms of expression of clock genes and clock controlled aanat2 gene in the photoreceptive pineal organ of catfish, Clarias gariepinus under natural conditions. BIOL RHYTHM RES 2021. [DOI: 10.1080/09291016.2021.1911550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Saurav Saha
- Environmental Endocrinology Laboratory, Department of Zoology, North-Eastern Hill University, Shillong, India
| | - Kshetrimayum Manisana Singh
- Environmental Endocrinology Laboratory, Department of Zoology, North-Eastern Hill University, Shillong, India
| | - Braj B. P. Gupta
- Environmental Endocrinology Laboratory, Department of Zoology, North-Eastern Hill University, Shillong, India
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7
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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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8
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徐 晶. A Review of Bird Migration Research. INTERNATIONAL JOURNAL OF ECOLOGY 2021. [DOI: 10.12677/ije.2021.102032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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9
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Yang Y, Liu Q, Wang T, Pan J. Wavelength-specific artificial light disrupts molecular clock in avian species: A power-calibrated statistical approach. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 265:114206. [PMID: 32599326 DOI: 10.1016/j.envpol.2020.114206] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/16/2020] [Accepted: 02/16/2020] [Indexed: 05/29/2023]
Abstract
Nighttime lighting is an increasingly important anthropogenic environmental stress on plants and animals. Exposure to unnatural lighting environments may disrupt the circadian rhythm of organisms. However, the sample size of relevant studies, e.g. disruption of the molecular circadian clock by light pollution, was small (<10), which led to low statistical power and difficulties in replicating prior results. Here, we developed a power-calibrated statistical approach to overcome these weaknesses. The results showed that the effect size of 2.48 in clock genes expression induced by artificial light would ensure the reproducibility of the results as high as 80%. Long-wavelength light (560-660 nm) entrained expressions of the positive core clock genes (e.g. cClock) and negative core clock genes (e.g. cCry1, cPer2) in robust circadian rhythmicity, whereas those clock genes were arrhythmic in short-wavelength light (380-480 nm). Further, we found artificial light could entrain the transcriptional-translational feedback loop of the molecular clock in a wavelength-dependent manner. The expression of the positive core clock genes (cBmal1, cBmal2 and cClock), cAanat gene and melatonin were the highest in short-wavelength light and lowest in long-wavelength light. For the negative regulators of the molecular clock (cCry1, cCry2, cPer2 and cPer3), the expression of which was the highest in long-wavelength light and lowest in short-wavelength light. Our statistical approach opens new opportunities to understand and strengthen conclusions, comparing with the studies with small sample sizes. We also provide comprehensive insight into the effect of wavelength-specific artificial light on the circadian rhythm of the molecular clock in avian species. Especially, the global lighting is shifting from "yellow" sodium lamps, which is more like the long-wavelength light, toward short-wavelength light (blue light)-enriched "white" light-emitting diodes (LEDs).
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Affiliation(s)
- Yefeng Yang
- Department of Biosystems Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Qiong Liu
- Department of Biosystems Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Tao Wang
- Department of Biosystems Engineering, Zhejiang University, Hangzhou, 310058, China
| | - Jinming Pan
- Department of Biosystems Engineering, Zhejiang University, Hangzhou, 310058, China.
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10
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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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11
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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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12
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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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13
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Pinzon-Rodriguez A, Bensch S, Muheim R. Expression patterns of cryptochrome genes in avian retina suggest involvement of Cry4 in light-dependent magnetoreception. J R Soc Interface 2018; 15:20180058. [PMID: 29593090 PMCID: PMC5908540 DOI: 10.1098/rsif.2018.0058] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/05/2018] [Indexed: 12/23/2022] Open
Abstract
The light-dependent magnetic compass of birds provides orientation information about the spatial alignment of the geomagnetic field. It is proposed to be located in the avian retina, and be mediated by a light-induced, biochemical radical-pair mechanism involving cryptochromes as putative receptor molecules. At the same time, cryptochromes are known for their role in the negative feedback loop in the circadian clock. We measured gene expression of Cry1, Cry2 and Cry4 in the retina, muscle and brain of zebra finches over the circadian day to assess whether they showed any circadian rhythmicity. We hypothesized that retinal cryptochromes involved in magnetoreception should be expressed at a constant level over the circadian day, because birds use a light-dependent magnetic compass for orientation not only during migration, but also for spatial orientation tasks in their daily life. Cryptochromes serving in circadian tasks, on the other hand, are expected to be expressed in a rhythmic (circadian) pattern. Cry1 and Cry2 displayed a daily variation in the retina as expected for circadian clock genes, while Cry4 expressed at constant levels over time. We conclude that Cry4 is the most likely candidate magnetoreceptor of the light-dependent magnetic compass in birds.
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Affiliation(s)
| | - Staffan Bensch
- Department of Biology, Lund University, Ecology Building, Lund 223 62, Sweden
| | - Rachel Muheim
- Department of Biology, Lund University, Biology Building B, Lund 223 62, Sweden
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Günther A, Einwich A, Sjulstok E, Feederle R, Bolte P, Koch KW, Solov’yov IA, Mouritsen H. Double-Cone Localization and Seasonal Expression Pattern Suggest a Role in Magnetoreception for European Robin Cryptochrome 4. Curr Biol 2018; 28:211-223.e4. [DOI: 10.1016/j.cub.2017.12.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 11/24/2017] [Accepted: 12/02/2017] [Indexed: 01/07/2023]
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Jiang N, Wang Z, Cao J, Dong Y, Chen Y. Effect of monochromatic light on circadian rhythmic expression of clock genes in the hypothalamus of chick. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 173:476-484. [PMID: 28668516 DOI: 10.1016/j.jphotobiol.2017.06.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 05/13/2017] [Accepted: 06/21/2017] [Indexed: 11/19/2022]
Abstract
To clarify the effect of monochromatic light on circadian clock gene expression in chick hypothalamus, a total 240 newly hatched chickens were reared under blue light (BL), green light (GL), red light (RL) and white light (WL), respectively. On the post-hatched day 14, 24-h profiles of seven core clock genes (cClock, cBmal1, cBmal2, cCry1, cCry2, cPer2 and cPer3) were measured at six time points (CT 0, CT 4, CT 8, CT 12, CT 16, CT 20, circadian time). We found all these clock genes expressed with a significant rhythmicity in different light wavelength groups. Meanwhile, cClock and cBmal1 showed a high level under GL, and followed a corresponding high expression of cCry1. However, RL decreased the expression levels of these genes. Be consistent with the mRNA level, CLOCK and BMAL1 proteins also showed a high level under GL. The CLOCK-like immunoreactive neurons were observed not only in the SCN, but also in the non-SCN brain region such as the nucleus anterior medialis hypothalami, the periventricularis nucleus, the paraventricular nucleus and the median eminence. All these results are consistent with the auto-regulatory circadian feedback loop, and indicate that GL may play an important role on the circadian time generation and development in the chick hypothalamus. Our results also suggest that the circadian clock in the chick hypothalamus such as non-SCN brain region were involved in the regulation of photo information.
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Affiliation(s)
- Nan Jiang
- Laboratory of Anatomy of Domestic Animals, College of Animal Medicine, China Agricultural University, Haidian, Beijing 100193, China
| | - Zixu Wang
- Laboratory of Anatomy of Domestic Animals, College of Animal Medicine, China Agricultural University, Haidian, Beijing 100193, China
| | - Jing Cao
- Laboratory of Anatomy of Domestic Animals, College of Animal Medicine, China Agricultural University, Haidian, Beijing 100193, China
| | - Yulan Dong
- Laboratory of Anatomy of Domestic Animals, College of Animal Medicine, China Agricultural University, Haidian, Beijing 100193, China
| | - Yaoxing Chen
- Laboratory of Anatomy of Domestic Animals, College of Animal Medicine, China Agricultural University, Haidian, Beijing 100193, China.
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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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Abstract
Retinas of all classes of vertebrates contain endogenous circadian clocks that control many aspects of retinal physiology, including retinal sensitivity to light, neurohormone synthesis, and cellular events such as rod disk shedding, intracellular signaling pathways, and gene expression. The vertebrate retina is an example of a “peripheral” oscillator that is particularly amenable to study because this tissue is well characterized, the relationships between the various cell types are extensively studied, and many local clock-controlled rhythms are known. Although the existence of a photoreceptor clock is well established in several species, emerging data are consistent with multiple or dual oscillators within the retina that interact to control local physiology. Aprominent example is the antiphasic regulation of melaton in and dopamine in photoreceptors and inner retina, respectively. This review focuses on the similarities and differences in the molecular mechanisms of the retinal versus the SCN oscillators, as well as on the expression of core components of the circadian clockwork in retina. Finally, the interactions between the retinal clock(s) and the master clock in the SCN are examined.
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Affiliation(s)
- Carla B Green
- Department of Biology, University of Virginia, Charlottesville, VA 22904, USA.
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Nießner C, Gross JC, Denzau S, Peichl L, Fleissner G, Wiltschko W, Wiltschko R. Seasonally Changing Cryptochrome 1b Expression in the Retinal Ganglion Cells of a Migrating Passerine Bird. PLoS One 2016; 11:e0150377. [PMID: 26953690 PMCID: PMC4783048 DOI: 10.1371/journal.pone.0150377] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 02/12/2016] [Indexed: 12/03/2022] Open
Abstract
Cryptochromes, blue-light absorbing proteins involved in the circadian clock, have been proposed to be the receptor molecules of the avian magnetic compass. In birds, several cryptochromes occur: Cryptochrome 2, Cryptochrome 4 and two splice products of Cryptochrome 1, Cry1a and Cry1b. With an antibody not distinguishing between the two splice products, Cryptochrome 1 had been detected in the retinal ganglion cells of garden warblers during migration. A recent study located Cry1a in the outer segments of UV/V-cones in the retina of domestic chickens and European robins, another migratory species. Here we report the presence of cryptochrome 1b (eCry1b) in retinal ganglion cells and displaced ganglion cells of European Robins, Erithacus rubecula. Immuno-histochemistry at the light microscopic and electron microscopic level showed eCry1b in the cell plasma, free in the cytosol as well as bound to membranes. This is supported by immuno-blotting. However, this applies only to robins in the migratory state. After the end of the migratory phase, the amount of eCry1b was markedly reduced and hardly detectable. In robins, the amount of eCry1b in the retinal ganglion cells varies with season: it appears to be strongly expressed only during the migratory period when the birds show nocturnal migratory restlessness. Since the avian magnetic compass does not seem to be restricted to the migratory phase, this seasonal variation makes a role of eCry1b in magnetoreception rather unlikely. Rather, it could be involved in physiological processes controlling migratory restlessness and thus enabling birds to perform their nocturnal flights.
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Affiliation(s)
- Christine Nießner
- Fachbereich Biowissenschaften der Goethe-Universität Frankfurt, Max-von-Laue-Str. 13, D-60438, Frankfurt am Main, Germany
| | - Julia Christina Gross
- Fachbereich Biowissenschaften der Goethe-Universität Frankfurt, Max-von-Laue-Str. 13, D-60438, Frankfurt am Main, Germany.,Haematology and Oncology and Developmental Biochemistry, University Medicine Göttingen, Justus-von-Liebig Weg 11, 37077, Göttingen, Germany
| | - Susanne Denzau
- Fachbereich Biowissenschaften der Goethe-Universität Frankfurt, Max-von-Laue-Str. 13, D-60438, Frankfurt am Main, Germany
| | - Leo Peichl
- Max Planck Institute for Brain Research, Max-von-Laue-Str. 4, D-60438, Frankfurt am Main, Germany
| | - Gerta Fleissner
- Fachbereich Biowissenschaften der Goethe-Universität Frankfurt, Max-von-Laue-Str. 13, D-60438, Frankfurt am Main, Germany
| | - Wolfgang Wiltschko
- Fachbereich Biowissenschaften der Goethe-Universität Frankfurt, Max-von-Laue-Str. 13, D-60438, Frankfurt am Main, Germany
| | - Roswitha Wiltschko
- Fachbereich Biowissenschaften der Goethe-Universität Frankfurt, Max-von-Laue-Str. 13, D-60438, Frankfurt am Main, Germany
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Ströckens F, Güntürkün O. Cryptochrome 1b: a possible inducer of visual lateralization in pigeons? Eur J Neurosci 2015; 43:162-8. [PMID: 26535920 DOI: 10.1111/ejn.13119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 01/22/2023]
Abstract
The visual system of adult pigeons shows a lateralization of object discrimination with a left hemispheric dominance on the behavioural, physiological and anatomical levels. The crucial trigger for the establishment of this asymmetry is the position of the embryo inside the egg, which exposes the right eye to light falling through the egg shell. As a result, the right-sided retina is more strongly stimulated with light during embryonic development. However, it is unknown how this embryonic light stimulation is transduced to the brain as rods and cones are not yet functional. A possible solution could be the blue-light-sensitive molecule cryptochrome 1 (Cry1), which is expressed in retinal ganglion cells (RGCs) of several mammalian and avian species. RGCs have been shown to be functional during the time of induction of asymmetry and possess projections to primary visual areas. Therefore, Cry1-containing RGCs could be responsible for induction of asymmetry. The aim of this study was to identify the expression pattern of the Cry1 subtype Cry1b in the retina of embryonic, post-hatch and adult pigeons by immunohistochemical staining and to show whether Cry1b-containing RGCs project to the optic tectum. Cry1b-positive cells were indeed mainly found in the RGC layer and to lesser extent in the inner nuclear layer at all ages, including the embryonic stage. Tracing in adult animals revealed that at least a subset of Cry1b-containing RGCs project to the optic tectum. Thus, Cry1b-containing RGCs within the embryonic retina could be involved in the induction of asymmetries in the visual system of pigeons.
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Affiliation(s)
- Felix Ströckens
- Department of Psychology, Institute of Cognitive Neuroscience, Biopsychology, Ruhr-University Bochum, Universitätsstraße 150, 44780, Bochum, Germany
| | - Onur Güntürkün
- Department of Psychology, Institute of Cognitive Neuroscience, Biopsychology, Ruhr-University Bochum, Universitätsstraße 150, 44780, Bochum, Germany
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Li Y, Cassone VM. Clock-Controlled Regulation of the Acute Effects of Norepinephrine on Chick Pineal Melatonin Rhythms. J Biol Rhythms 2015; 30:519-32. [PMID: 26446873 DOI: 10.1177/0748730415607060] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The chicken pineal gland synthesizes and releases melatonin rhythmically in light/dark (LD) cycles, with high melatonin levels during the dark phase, and in constant darkness (DD) for several cycles before it gradually damps to arrhythmicity in DD. Daily administration of norepinephrine (NE) in vivo and in vitro prevents the damping and restores the melatonin rhythm. To investigate the role of the circadian clock on melatonin rhythm damping and of its restoration by NE, the effects of NE administration at different phases of the melatonin cycle revealed a robust rhythm in NE sensitivity in which NE efficacy in increasing melatonin amplitude peaked in late subjective night and early subjective day, suggesting a clock underlying NE sensitivity. However, NE itself had no effect on circadian phase or period of the melatonin rhythms. Transcriptional analyses indicated that even though the rhythm of melatonin output damped to arrhythmicity, messenger RNA (mRNA) encoding clock genes gper2, gper3, gBmal1, gclock, gcry1, and gcry2; enzymes associated with melatonin biosynthesis; and enzymes involved in cyclic nucleotide signaling remained robustly rhythmic. Of these, only gADCY1 (adenylate cyclase 1) and gPDE4D (cAMP-specific 3',5'-cyclic phosphodiesterase 4D) were affected by NE administration at the mRNA levels, and only ADCY1 was affected at the protein level. The data strongly suggest that damping of the melatonin rhythm in the chick pineal gland occurs at the posttranscriptional level and that a major role of the clock is to regulate pinealocytes' sensitivity to neuronal input from the brain.
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Affiliation(s)
- Ye Li
- Department of Biology, University of Kentucky, Lexington, Kentucky
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Landler L, Painter MS, Youmans PW, Hopkins WA, Phillips JB. Spontaneous magnetic alignment by yearling snapping turtles: rapid association of radio frequency dependent pattern of magnetic input with novel surroundings. PLoS One 2015; 10:e0124728. [PMID: 25978736 PMCID: PMC4433231 DOI: 10.1371/journal.pone.0124728] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 03/03/2015] [Indexed: 11/18/2022] Open
Abstract
We investigated spontaneous magnetic alignment (SMA) by juvenile snapping turtles using exposure to low-level radio frequency (RF) fields at the Larmor frequency to help characterize the underlying sensory mechanism. Turtles, first introduced to the testing environment without the presence of RF aligned consistently towards magnetic north when subsequent magnetic testing conditions were also free of RF ('RF off → RF off'), but were disoriented when subsequently exposed to RF ('RF off → RF on'). In contrast, animals initially introduced to the testing environment with RF present were disoriented when tested without RF ('RF on → RF off'), but aligned towards magnetic south when tested with RF ('RF on → RF on'). Sensitivity of the SMA response of yearling turtles to RF is consistent with the involvement of a radical pair mechanism. Furthermore, the effect of RF appears to result from a change in the pattern of magnetic input, rather than elimination of magnetic input altogether, as proposed to explain similar effects in other systems/organisms. The findings show that turtles first exposed to a novel environment form a lasting association between the pattern of magnetic input and their surroundings. However, under natural conditions turtles would never experience a change in the pattern of magnetic input. Therefore, if turtles form a similar association of magnetic cues with the surroundings each time they encounter unfamiliar habitat, as seems likely, the same pattern of magnetic input would be associated with multiple sites/localities. This would be expected from a sensory input that functions as a global reference frame, helping to place multiple locales (i.e., multiple local landmark arrays) into register to form a global map of familiar space.
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Affiliation(s)
- Lukas Landler
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Michael S. Painter
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Paul W. Youmans
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - William A. Hopkins
- Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, Virginia, United States of America
| | - John B. Phillips
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
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Wang J, Du X, Pan W, Wang X, Wu W. Photoactivation of the cryptochrome/photolyase superfamily. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2015. [DOI: 10.1016/j.jphotochemrev.2014.12.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Abstract
The circadian timekeeping system appears more complex in birds than in mammals. In mammals, the main pacemaker is centralized in the suprachiasmatic nuclei, whereas in birds, the pacemaker involves the interplay between the pineal and hypothalamic oscillators. In order to investigate the consequence of this complex mechanism, we propose here a mathematical model for the bird circadian clock. The model is based on the internal resonance between the pineal and hypothalamic oscillators, each described by Goodwin-like equations. We show that, consistently with experimental observations, self-sustained oscillations can be generated by mutual inhibitory coupling of the 2 clocks, even if individual oscillators present damped oscillations. We study the effect of constant and periodic administrations of melatonin, which, in intact birds, acts as the coupling variable between the pineal and the hypothalamus, and compare the prediction of the model with the experiments performed in pinealectomized birds. We also assess the entrainment properties when the system is subject to light-dark cycles. Analyses of the entrainment range, resynchronization time after jet lag, and entrainment phase with respect to the photoperiod lead us to formulate hypotheses about the physiological advantage of the particular architecture of the avian circadian clock. Although minimal, our model opens promising perspectives in modeling and understanding the bird circadian clock.
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Affiliation(s)
- Aurore Woller
- Unité de Chronobiologie Théorique, CP 231, Faculté des Sciences, Université Libre de Bruxelles, Bruxelles, Belgium
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Wiltschko R, Wiltschko W. Sensing magnetic directions in birds: radical pair processes involving cryptochrome. BIOSENSORS-BASEL 2014; 4:221-42. [PMID: 25587420 PMCID: PMC4264356 DOI: 10.3390/bios4030221] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 07/14/2014] [Accepted: 07/18/2014] [Indexed: 11/16/2022]
Abstract
Birds can use the geomagnetic field for compass orientation. Behavioral experiments, mostly with migrating passerines, revealed three characteristics of the avian magnetic compass: (1) it works spontaneously only in a narrow functional window around the intensity of the ambient magnetic field, but can adapt to other intensities, (2) it is an “inclination compass”, not based on the polarity of the magnetic field, but the axial course of the field lines, and (3) it requires short-wavelength light from UV to 565 nm Green. The Radical Pair-Model of magnetoreception can explain these properties by proposing spin-chemical processes in photopigments as underlying mechanism. Applying radio frequency fields, a diagnostic tool for radical pair processes, supports an involvement of a radical pair mechanism in avian magnetoreception: added to the geomagnetic field, they disrupted orientation, presumably by interfering with the receptive processes. Cryptochromes have been suggested as receptor molecules. Cry1a is found in the eyes of birds, where it is located at the membranes of the disks in the outer segments of the UV-cones in chickens and robins. Immuno-histochemical studies show that it is activated by the wavelengths of light that allow magnetic compass orientation in birds.
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Affiliation(s)
- Roswitha Wiltschko
- Fachbereich Biowissenschaften, J.W. Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany; E-Mail:
| | - Wolfgang Wiltschko
- Fachbereich Biowissenschaften, J.W. Goethe-Universität Frankfurt, Max von Laue Straße 13, D-60438 Frankfurt am Main, Germany; E-Mail:
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Kim YM, Choi J, Lee HY, Lee GW, Lee YH, Choi D. dbCRY: a Web-based comparative and evolutionary genomics platform for blue-light receptors. DATABASE-THE JOURNAL OF BIOLOGICAL DATABASES AND CURATION 2014; 2014:bau037. [PMID: 24816342 PMCID: PMC4016680 DOI: 10.1093/database/bau037] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Cryptochromes are flavoproteins that play a central role in the circadian oscillations of all living organisms except archaea. Cryptochromes are clustered into three subfamilies: plant-type cryptochromes, animal-type cryptochromes and cryptochrome-DASH proteins. These subfamilies are composed of photolyase/cryptochrome superfamily with 6–4 photolyase and cyclobutane pyrimidine dimer photolyase. Cryptochromes have conserved domain architectures with two distinct domains, an N-terminal photolyase-related domain and a C-terminal domain. Although the molecular function and domain architecture of cryptochromes are conserved, their molecular mechanisms differ between plants and animals. Thus, cryptochromes are one of the best candidates for comparative and evolutionary studies. Here, we have developed a Web-based platform for comparative and evolutionary studies of cryptochromes, dbCRY (http://www.dbcryptochrome.org/). A pipeline built upon the consensus domain profile was applied to 1438 genomes and identified 1309 genes. To support comparative and evolutionary genomics studies, the Web interface provides diverse functions such as (i) browsing by species, (ii) protein domain analysis, (iii) multiple sequence alignment, (iv) homology search and (v) extended analysis opportunities through the implementation of ‘Favorite Browser’ powered by the Comparative Fungal Genomics Platform 2.0 (CFGP 2.0; http://cfgp.snu.ac.kr/). dbCRY would serve as a standardized and systematic solution for cryptochrome genomics studies. Database URL:http://www.dbcryptochrome.org/
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Affiliation(s)
- Yong-Min Kim
- Department of Plant Science and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Korea, Department of Agricultural Biotechnology, Fungal Bioinformatics Laboratory, Seoul National University, Seoul 151-921, Korea, Department of Bioinformatics and Life Science, Soongsil University, Seoul 156-743, Korea and Center for Fungal Genetic Resources and Center for Fungal Pathogenesis, Seoul National University, Seoul 151-742, Korea
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Wiltschko R, Munro U, Ford H, Stapput K, Thalau P, Wiltschko W. Orientation of migratory birds under ultraviolet light. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:399-407. [PMID: 24718656 DOI: 10.1007/s00359-014-0898-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 03/05/2014] [Accepted: 03/07/2014] [Indexed: 11/25/2022]
Abstract
In view of the finding that cryptochrome 1a, the putative receptor molecule for the avian magnetic compass, is restricted to the ultraviolet single cones in European Robins, we studied the orientation behaviour of robins and Australian Silvereyes under monochromatic ultraviolet (UV) light. At low intensity UV light of 0.3 mW/m(2), birds showed normal migratory orientation by their inclination compass, with the directional information originating in radical pair processes in the eye. At 2.8 mW/m(2), robins showed an axial preference in the east-west axis, whereas silvereyes preferred an easterly direction. At 5.7 mW/m(2), robins changed direction to a north-south axis. When UV light was combined with yellow light, robins showed easterly 'fixed direction' responses, which changed to disorientation when their upper beak was locally anaesthetised with xylocaine, indicating that they were controlled by the magnetite-based receptors in the beak. Orientation under UV light thus appears to be similar to that observed under blue, turquoise and green light, albeit the UV responses occur at lower light levels, probably because of the greater light sensitivity of the UV cones. The orientation under UV light and green light suggests that at least at the level of the retina, magnetoreception and vision are largely independent of each other.
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Affiliation(s)
- Roswitha Wiltschko
- Fachbereich Biowissenschaften der, J.W.Goethe-Universität Frankfurt, Max von Laue Straße 13, 60438, Frankfurt am Main, Germany,
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Singh D, Rani S, Kumar V. Daily expression of six clock genes in central and peripheral tissues of a night-migratory songbird: evidence for tissue-specific circadian timing. Chronobiol Int 2013; 30:1208-17. [PMID: 23971885 DOI: 10.3109/07420528.2013.810632] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In birds, independent circadian clocks reside in the retina, pineal, and hypothalamus, which interact with each other and produce circadian time at the functional level. However, less is known of the molecular clockwork, and of the integration between central and peripheral clocks in birds. The present study investigated this, by monitoring the timed expression of five core clock genes (Per2. Cry1. Cry2. Bmal1, and Clock) and one clock-controlled gene (E4bp4) in a night-migratory songbird, the redheaded bunting (rb; Emberiza bruniceps). The authors first partially cloned these six genes, and then measured their 24-h profiles in central (retina, hypothalamus) and peripheral (liver, heart, stomach, gut, testes) tissues, collected at six times (zeitgeber time 2 [ZT2], ZT6, ZT11, ZT13, ZT18, and ZT23; ZT0 = lights on) from birds (n = 5 per ZT) on 12 h:12 h light-dark cycle. rbPer2. rbCry1. rbBmal1, and rbClock were expressed with a significant rhythm in all the tissues, except in the retina (only rbClock) and testes. rbCry2, however, had tissue-specific expression pattern: a significant rhythm in the hypothalamus, heart, and gut, but not in the retina, liver, stomach, and testes. rbE4bp4 had a significant mRNA rhythm in all the tissues, except retina. Further, rbPer2 mRNA peak was phase aligned with lights on, whereas rbCry1. rbBmal1, and rbE4bp4 mRNA peaks were phase aligned with lights off. rbCry2 and rbClock had tissue-specific scattered peaks. For example, both rbCry2 and rbClock peaks were close to rbCry1 and rbBmal1 peaks, respectively, in the hypothalamus, but not in other tissues. The results are consistent with the autoregulatory circadian feedback loop, and indicate a conserved tissue-level circadian time generation in buntings. Variable phase relationships between gene pairs forming positive and negative limbs of the feedback loop may suggest the tissue-specific contribution of individual core circadian genes in the circadian time generation.
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Affiliation(s)
- Devraj Singh
- DST-IRHPA Center for Excellence in Biological Rhythms Research, Department of Zoology, University of Delhi , Delhi , India and
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Nießner C, Denzau S, Stapput K, Ahmad M, Peichl L, Wiltschko W, Wiltschko R. Magnetoreception: activated cryptochrome 1a concurs with magnetic orientation in birds. J R Soc Interface 2013; 10:20130638. [PMID: 23966619 PMCID: PMC3785833 DOI: 10.1098/rsif.2013.0638] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The radical pair model proposes that the avian magnetic compass is based on radical pair processes in the eye, with cryptochrome, a flavoprotein, suggested as receptor molecule. Cryptochrome 1a (Cry1a) is localized at the discs of the outer segments of the UV/violet cones of European robins and chickens. Here, we show the activation characteristics of a bird cryptochrome in vivo under natural conditions. We exposed chickens for 30 min to different light regimes and analysed the amount of Cry1a labelled with an antiserum against an epitope at the C-terminus of this protein. The staining after exposure to sunlight and to darkness indicated that the antiserum labels only an illuminated, activated form of Cry1a. Exposure to narrow-bandwidth lights of various wavelengths revealed activated Cry1a at UV, blue and turquoise light. With green and yellow, the amount of activated Cry1a was reduced, and with red, as in the dark, no activated Cry1a was labelled. Activated Cry1a is thus found at all those wavelengths at which birds can orient using their magnetic inclination compass, supporting the role of Cry1a as receptor molecule. The observation that activated Cry1a and well-oriented behaviour occur at 565 nm green light, a wavelength not absorbed by the fully oxidized form of cryptochrome, suggests that a state other than the previously suggested Trp•/FAD• radical pair formed during photoreduction is crucial for detecting magnetic directions.
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Affiliation(s)
- Christine Nießner
- FB Biowissenschaften, J.W. Goethe-Universität Frankfurt, Siesmayerstrasse 70, 60054 Frankfurt am Main, Germany
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Biological clocks in the duodenum and the diurnal regulation of duodenal and plasma serotonin. PLoS One 2013; 8:e58477. [PMID: 23737937 PMCID: PMC3667830 DOI: 10.1371/journal.pone.0058477] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 02/05/2013] [Indexed: 11/19/2022] Open
Abstract
Serotonin in blood plasma is primarily synthesized in the duodenum, as brain derived serotonin does not cross the blood-brain barrier. Because serotonin in the brain and retina is synthesized under the control of a circadian clock, we sought to determine if a circadian clock in the duodenum regulates serotonin synthesis and release in blood. We examined gene expression in the duodenum of chickens at different times of the day and found that the duodenum rhythmically expresses molecular circadian clock genes and genes controlling serotonin biosynthesis, specifically tryptophan hydroxylase, in a light dark cycle (LD). Analysis of the duodenum and blood plasma showed that the amount of serotonin in the duodenum varies across the day and that serotonin profiles in blood plasma are also rhythmic in LD, but were not rhythmic in constant darkness. Because serotonin in the gut affects duodenal nutrient absorption and gut motility, the control of serotonin production in the duodenum by LD cycles could provide an additional mechanism by which the external environment controls nutrient uptake and digestive function. The diurnal regulation of plasma serotonin may also serve as an additional biochemical signal in the blood encoding time and could be used by target tissues to indicate the status of nutrient absorption.
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Huang H, Wang Z, Weng SJ, Sun XH, Yang XL. Neuromodulatory role of melatonin in retinal information processing. Prog Retin Eye Res 2013; 32:64-87. [PMID: 22986412 DOI: 10.1016/j.preteyeres.2012.07.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 07/24/2012] [Accepted: 07/25/2012] [Indexed: 12/15/2022]
Affiliation(s)
- Hai Huang
- Institute of Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, PR China
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Denzau S, Nießner C, Rogers L, Wiltschko W. Ontogenetic development of magnetic compass orientation in domestic chickens (Gallus gallus). J Exp Biol 2013; 216:3143-7. [DOI: 10.1242/jeb.088815] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Summary
Domestic chickens (Gallus gallus) can be trained to search for a social stimulus in a specific magnetic direction, and cryptochrome 1a found in the retina has been proposed as a receptor molecule mediating magnetic directions. The present study combines immuno-histochemical and behavioural data to analyse the ontogenetic development of this ability. Newly hatched chicks already have a small amount of cryptochrome 1a in their violet cones; on day 5, the amount of cryptochrome 1a has reached the same level as in adult chickens, suggesting that the physical basis for magnetoreception is present. In behavioural tests, however, young chicks 5 to 7 days old failed to show a preference of the training direction; on days 8, 9 and 12, they could be successfully trained to search along a specific magnetic axis. Trained and tested again a week later, the chicks that had not shown a directional preference on day 5 to 7 continued to search randomly, while the chicks tested from day 8 onward preferred the correct magnetic axis when tested one week later. The observation that the magnetic compass is not functional before day 8 suggests that certain maturation processes in the magnetosensitive system in the brain are not yet complete before that day. The reasons why chicks that have been trained before that day fail to learn the task later remain unclear.
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Bischof HJ, Nießner C, Peichl L, Wiltschko R, Wiltschko W. Avian ultraviolet/violet cones as magnetoreceptors: The problem of separating visual and magnetic information. Commun Integr Biol 2012; 4:713-6. [PMID: 22446535 DOI: 10.4161/cib.17338] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In a recent paper, we described the localization of cryptochrome 1a in the retina of domestic chickens, Gallus gallus, and European robins, Erithacus rubecula: Cryptochrome 1a was found exclusively along the membranes of the disks in the outer segments of the ultraviolet/violet single cones. Cryptochrome has been suggested to act as receptor molecule for the avian magnetic compass, which would mean that the UV/V cones have a double function: they mediate vision in the short-wavelength range and, at the same time, magnetic directional information. This has important implications and raises a number of questions, in particular, how the two types of input are separated. Here, we point out several possibilities how this could be achieved.
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Caprioli M, Ambrosini R, Boncoraglio G, Gatti E, Romano A, Romano M, Rubolini D, Gianfranceschi L, Saino N. Clock gene variation is associated with breeding phenology and maybe under directional selection in the migratory barn swallow. PLoS One 2012; 7:e35140. [PMID: 22506071 PMCID: PMC3323641 DOI: 10.1371/journal.pone.0035140] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 03/08/2012] [Indexed: 11/18/2022] Open
Abstract
Background In diverse taxa, photoperiodic responses that cause seasonal physiological and behavioural shifts are controlled by genes, including the vertebrate Clock orthologues, that encode for circadian oscillator mechanisms. While the genetic network behind circadian rhythms is well described, relatively few reports exist of the phenological consequences of and selection on Clock genes in the wild. Here, we investigated variation in breeding phenology in relation to Clock genetic diversity in a long-distance migratory bird, the barn swallow (Hirundo rustica). Methodology/Principal Findings In a sample of 922 adult barn swallows from a single population breeding in Italy we found one very common (Q7) and three rare (Q5, Q6, Q8) length variants of a functionally significant polyglutamine repeat. Rare (2.9%) Q7/Q8 heterozygous females, but not males, bred significantly later than common (91.5%) Q7/Q7 females, consistent with the expectation that ‘long’ alleles cause late breeding, as observed in a resident population of another bird species. Because breeding date depends on arrival date from migration, present results suggest that the association between breeding date and Clock might be mediated by migration phenology. In addition, fecundity selection appears to be operating against Q7/Q8 because late migrating/breeding swallows have fewer clutches per season, and late breeding has additional negative selection effects via reduced offspring longevity. Genotype frequencies varied marginally non-significantly with age, as Q7/Q8 frequency showed a 4-fold reduction in old individuals. This result suggests negative viability selection against Q7/Q8, possibly mediated by costs of late breeding. Conclusions/Significance This is the first study of migratory birds showing an association between breeding phenology and Clock genotype and suggesting that negative selection occurs on a phenologically deviant genotype. Low polymorphism at Clock may constrain microevolutionary phenological response to changing climate, and may thus contribute to the decline of barn swallow populations.
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Affiliation(s)
- Manuela Caprioli
- Dipartimento di Biologia, Università degli Studi di Milano, Milano, Italy
| | - Roberto Ambrosini
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milano, Italy
| | | | - Emanuele Gatti
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milano, Italy
| | - Andrea Romano
- Dipartimento di Biologia, Università degli Studi di Milano, Milano, Italy
| | - Maria Romano
- Dipartimento di Biologia, Università degli Studi di Milano, Milano, Italy
| | - Diego Rubolini
- Dipartimento di Biologia, Università degli Studi di Milano, Milano, Italy
| | - Luca Gianfranceschi
- Dipartimento di Scienze Biomolecolari e Biotecnologie, Università degli Studi di Milano, Milano, Italy
| | - Nicola Saino
- Dipartimento di Biologia, Università degli Studi di Milano, Milano, Italy
- * E-mail:
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Zeman M, Herichová I. Circadian melatonin production develops faster in birds than in mammals. Gen Comp Endocrinol 2011; 172:23-30. [PMID: 21199656 DOI: 10.1016/j.ygcen.2010.12.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 12/24/2010] [Indexed: 11/17/2022]
Abstract
The development of circadian rhythmicity of melatonin biosynthesis in the pineal gland starts during embryonic period in birds while it is delayed to the postnatal life in mammals. Daily rhythms of melatonin in isolated pinealocytes and in intact pineal glands under in vivo conditions were demonstrated during the last third of embryonic development in chick embryos, with higher levels during the dark (D) than during the light (L) phase. In addition to the LD cycle, rhythmic temperature changes with the amplitude of 4.5°C can entrain rhythmic melatonin biosynthesis in chick embryos, with higher concentrations found during the low-temperature phase (33.0 vs 37.5°C). Molecular clockwork starts to operate during the embryonic life in birds in line with the early development of melatonin rhythmicity. Expression of per2 and cry genes is rhythmic at least at day 16 and 18, respectively, and the circadian system operates in a mature-like manner soon after hatching. Rhythmic oscillations are detected earlier in the central oscillator (the pineal gland) than in the peripheral structures, reflecting the synchronization of individual cells which is necessary for detection of the rhythm. The early development of the circadian system in birds reflects an absence of rhythmic maternal melatonin which in mammals synchronizes physiological processes of offspring. Developmental consequences of modified development of circadian system for its stability later in development are not known and should be studied.
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Affiliation(s)
- Michal Zeman
- Department of Animal Physiology and Ethology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic.
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Wang G, Wingfield JC. Immunocytochemical study of rhodopsin-containing putative encephalic photoreceptors in house sparrow, Passer domesticus. Gen Comp Endocrinol 2011; 170:589-96. [PMID: 21118688 DOI: 10.1016/j.ygcen.2010.11.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2009] [Revised: 10/03/2010] [Accepted: 11/18/2010] [Indexed: 11/19/2022]
Abstract
In seasonally breeding birds, encephalic photoreceptors (EPs) play an important role in regulating photoperiodic gonadal responses. Multiple photopigments have been suggested as the putative EPs, including rhodopsin, melanopsin, VA opsin and the cryptochromes. As for rhodopsin, two potential brain sites, the lateral septum (SL) and the infundibulum (INF) have been reported to co-express rhodopsin immunoreactivity (rhodopsin-ir) with vasoactive intestinal polypeptide immunoreactivity (VIP-ir) in groups of cerebrospinal fluid-contacting (CSF) cells, hypothesized to be the EPs for gonadal responses. In order to confirm the presence of rhodopsin in seasonally breeding birds and examine whether these EPs show daily change as do the photopigments in the retina and pineal gland, the present study immunocytochemically investigated: (1) the presence of rhodopsin expression in the deep brain of the house sparrow, Passer domesticus maintained in short days, and (2) rhythmic expression of rhodopsin and VIP in both SL and INF at Zeitgeber time (ZT) 1 and ZT 17 in house sparrows. Rhodopsin-ir and VIP-ir were observed in both areas of sparrow brains as previously described in other avian species but with a novel rod-like rhodopsin-ir cell type in the INF and novel expression of rhodopsin-ir fiber close to the preoptic area. Daily changes of rhodopsin-ir and VIP-ir cell number were revealed in the INF, but not in the SL. More rhodopsin-ir and fewer VIP-ir cells were found at ZT 17 than at ZT 1. In the median eminence, rhodopsin-ir fibers were only observed at ZT 1, and the relative optic density (ROD) of VIP-ir fibers was higher at ZT 1 than ZT 17. The results indicate daily changes of EPs in the IN and ME, suggesting a role of EPs in the orchestration of photoperiodic gonadal recrudesence.
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Affiliation(s)
- Gang Wang
- Department of Biology, University of Washington, Seattle, WA 98195, USA.
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Naidu KS, Morgan LW, Bailey MJ. Inflammation in the avian spleen: timing is everything. BMC Mol Biol 2010; 11:104. [PMID: 21194436 PMCID: PMC3027090 DOI: 10.1186/1471-2199-11-104] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 12/31/2010] [Indexed: 12/03/2022] Open
Abstract
Background The synchrony of an organism with both its external and internal environment is critical to well-being and survival. As a result, organisms display daily cycles of physiology and behavior termed circadian rhythms. At the cellular level, circadian rhythms originate via interlocked autoregulatory feedback loops consisting of circadian clock genes and their proteins. These regulatory loops provide the molecular framework that enables the intracellular circadian timing system necessary to generate and maintain subsequent 24 hr rhythms. In the present study we examine the daily control of circadian clock genes and regulation of the inflammatory response by the circadian clock in the spleen. Results Our results reveal that circadian clock genes as well as proinflammatory cytokines, including Tnfά and IL-1β, display rhythmic oscillations of mRNA abundance over a 24 hr cycle. LPS-induced systemic inflammation applied at midday vs. midnight reveals a differential response of proinflammatory cytokine induction in the spleen, suggesting a daily rhythm of inflammation. Exogenous melatonin administration at midday prior to LPS stimulation conveys pleiotropic effects, enhancing and repressing inflammatory cytokines, indicating melatonin functions as both a pro- and anti-inflammatory molecule in the spleen. Conclusion In summary, a daily oscillation of circadian clock genes and inflammatory cytokines as well as the ability of melatonin to function as a daily mediator of inflammation provides valuable information to aid in deciphering how the circadian timing system regulates immune function at the molecular level. However, further research is needed to clarify the precise mechanisms by which the circadian clock and melatonin have an impact upon daily immune functions in the periphery.
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Affiliation(s)
- Kallur S Naidu
- The Center for Biological Clocks Research, Department of Poultry Science, Texas A&M University, College Station, TX 77843-2472, USA
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Tischkau SA, Howell RE, Hickok JR, Krager SL, Bahr JM. The Luteinizing Hormone Surge Regulates Circadian Clock Gene Expression in the Chicken Ovary. Chronobiol Int 2010; 28:10-20. [DOI: 10.3109/07420528.2010.530363] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Kumar V, Wingfield JC, Dawson A, Ramenofsky M, Rani S, Bartell P. Biological clocks and regulation of seasonal reproduction and migration in birds. Physiol Biochem Zool 2010; 83:827-35. [PMID: 20604684 DOI: 10.1086/652243] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Timekeeping is important at two levels: to time changes in physiology and behavior within each day and within each year. For the former, birds have a system of at least three independent circadian clocks present in the retina of the eyes, the pineal gland, and the hypothalamus. This differs from the situation in mammals in which the input, pacemaker, and output are localized in different structures. Each bird clock interacts with at least one other clock, and together, they appear to form a centralized clock system that keeps daily time. These clocks have a powerful endogenous component, and the daily light-dark cycle entrains them to 24 h. The timing and duration of life history stages that make up annual cycle of an individual must also be controlled by some form of timekeeping. However, evidence for the existence of an equivalent endogenous circannual clock is less clear. Environmental cues, particularly photoperiod, appear to have a more direct role than simply entraining the clock to calendar time. For example, the timing of migration is probably greatly influenced by photoperiod, but its manifestation each day, as Zugunruhe, appears to be under circadian control. Migration involves marked changes in physiology to cope with the energetic demands. There is still much that we do not know about how organisms' timekeeping systems respond to their natural environment, particularly how salient signals from the environment are perceived and then transduced into appropriately timed biological functions. However, given that changes in environmental input affects the clock, increasing human disturbance of the environment is likely to adversely affect these systems.
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Affiliation(s)
- Vinod Kumar
- Department of Science and Technology, University of Delhi, Delhi 110 007, India.
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Light-dependent magnetic compass in Iberian green frog tadpoles. Naturwissenschaften 2010; 97:1077-88. [DOI: 10.1007/s00114-010-0730-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Revised: 10/12/2010] [Accepted: 10/13/2010] [Indexed: 10/18/2022]
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Rosenstein RE, Pandi-Perumal SR, Srinivasan V, Spence DW, Brown GM, Cardinali DP. Melatonin as a therapeutic tool in ophthalmology: implications for glaucoma and uveitis. J Pineal Res 2010; 49:1-13. [PMID: 20492443 DOI: 10.1111/j.1600-079x.2010.00764.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Several lines of evidence support the view that increased free radical generation and altered nitric oxide (NO) metabolism play a role in the pathogenesis of highly prevalent ocular diseases, such as glaucoma and uveitis. Data are discussed indicating that melatonin, being an efficient antioxidant that displays antinitridergic properties, has a promising role in the treatment of these ocular dysfunctions. Melatonin synthesis occurs in the eye of most species, and melatonin receptors are localized in different ocular structures. In view of the fact that melatonin lacks significant adverse collateral effects even at high doses, the application of melatonin could potentially protect ocular tissues by effectively scavenging free radicals and excessive amounts of NO generated in the glaucomatous or uveitic eye.
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Affiliation(s)
- Ruth E Rosenstein
- Department of Human Biochemistry, School of Medicine, CEFyBO, University of Buenos Aires, CONICET, Buenos Aires, Argentina.
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Liedvogel M, Mouritsen H. Cryptochromes--a potential magnetoreceptor: what do we know and what do we want to know? J R Soc Interface 2010; 7 Suppl 2:S147-62. [PMID: 19906675 PMCID: PMC2844001 DOI: 10.1098/rsif.2009.0411.focus] [Citation(s) in RCA: 159] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Accepted: 10/22/2009] [Indexed: 01/14/2023] Open
Abstract
Cryptochromes have been suggested to be the primary magnetoreceptor molecules underlying light-dependent magnetic compass detection in migratory birds. Here we review and evaluate (i) what is known about these candidate magnetoreceptor molecules, (ii) what characteristics cryptochrome molecules must fulfil to possibly underlie light-dependent, radical pair based magnetoreception, (iii) what evidence supports the involvement of cryptochromes in magnetoreception, and (iv) what needs to be addressed in future research. The review focuses primarily on our knowledge of cryptochromes in the context of magnetoreception.
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Affiliation(s)
- Miriam Liedvogel
- AG Neurosensorik (Animal Navigation), Institut für Biologie und Umweltwissenschaften, University of Oldenburg, 26111 Oldenburg, Germany.
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Keary N, Ruploh T, Voss J, Thalau P, Wiltschko R, Wiltschko W, Bischof HJ. Oscillating magnetic field disrupts magnetic orientation in Zebra finches, Taeniopygia guttata. Front Zool 2009; 6:25. [PMID: 19852792 PMCID: PMC2774300 DOI: 10.1186/1742-9994-6-25] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Accepted: 10/23/2009] [Indexed: 11/14/2022] Open
Abstract
Background Zebra finches can be trained to use the geomagnetic field as a directional cue for short distance orientation. The physical mechanisms underlying the primary processes of magnetoreception are, however, largely unknown. Two hypotheses of how birds perceive magnetic information are mainly discussed, one dealing with modulation of radical pair processes in retinal structures, the other assuming that iron deposits in the upper beak of the birds are involved. Oscillating magnetic fields in the MHz range disturb radical pair mechanisms but do not affect magnetic particles. Thus, application of such oscillating fields in behavioral experiments can be used as a diagnostic tool to decide between the two alternatives. Methods In a setup that eliminates all directional cues except the geomagnetic field zebra finches were trained to search for food in the magnetic north/south axis. The birds were then tested for orientation performance in two magnetic conditions. In condition 1 the horizontal component of the geomagnetic field was shifted by 90 degrees using a helmholtz coil. In condition 2 a high frequently oscillating field (1.156 MHz) was applied in addition to the shifted field. Another group of birds was trained to solve the orientation task, but with visual landmarks as directional cue. The birds were then tested for their orientation performance in the same magnetic conditions as applied for the first experiment. Results The zebra finches could be trained successfully to orient in the geomagnetic field for food search in the north/south axis. They were also well oriented in test condition 1, with the magnetic field shifted horizontally by 90 degrees. In contrast, when the oscillating field was added, the directional choices during food search were randomly distributed. Birds that were trained to visually guided orientation showed no difference of orientation performance in the two magnetic conditions. Conclusion The results indicate that zebra finches use a receptor that bases on radical pair processes for sensing the direction of the earth magnetic field in this short distance orientation behavior.
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Affiliation(s)
- Nina Keary
- Lehrstuhl Verhaltensforschung, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
| | - Tim Ruploh
- Lehrstuhl Verhaltensforschung, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
| | - Joe Voss
- Lehrstuhl Verhaltensforschung, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
| | - Peter Thalau
- FB Biowissenschaften, J. W. Goethe-Universität, Siesmayerstr. 70, D-60054 Frankfurt/Main, Germany
| | - Roswitha Wiltschko
- FB Biowissenschaften, J. W. Goethe-Universität, Siesmayerstr. 70, D-60054 Frankfurt/Main, Germany
| | - Wolfgang Wiltschko
- FB Biowissenschaften, J. W. Goethe-Universität, Siesmayerstr. 70, D-60054 Frankfurt/Main, Germany
| | - Hans-Joachim Bischof
- Lehrstuhl Verhaltensforschung, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
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Cassone VM, Paulose JK, Whitfield-Rucker MG, Peters JL. Time's arrow flies like a bird: two paradoxes for avian circadian biology. Gen Comp Endocrinol 2009; 163:109-16. [PMID: 19523398 PMCID: PMC2710421 DOI: 10.1016/j.ygcen.2009.01.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 12/29/2008] [Accepted: 01/13/2009] [Indexed: 01/29/2023]
Abstract
Biological timekeeping in birds is a fundamental feature of avian physiology, behavior and ecology. The physiological basis for avian circadian rhythmicity has pointed to a multi-oscillator system of mutually coupled pacemakers in the pineal gland, eyes and hypothalamic suprachiasmatic nuclei (SCN). In passerines, the role of the pineal gland and its hormone melatonin is particularly important. More recent molecular biological studies have pointed to a highly conserved mechanism involving rhythmic transcription and translation of "clock genes". However, studies attempting to reconcile the physiological role of pineal melatonin with molecular studies have largely failed. Recent work in our laboratory has suggested that melatonin-sensitive physiological processes are only loosely coupled to transcriptional oscillations. Similarly, although the pineal gland has been shown to be critical for overt circadian behaviors, its role in annual cycles of reproductive function appears to be minimal. Recent work on the seasonal control of birdsong, however, suggests that, although the pineal gland does not directly affect gonadal cycles, it is important for seasonal changes in song. Experimental analyses that address these paradoxes will shed light on the roles the biological clock play in birds and in vertebrates in general.
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Affiliation(s)
- Vincent M Cassone
- Department of Biology, Thomas Hunt Morgan Building, University of Kentucky, 675 Rose Street, Lexington, KY 40506, USA.
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Helfer G, Fidler AE, Vallone D, Foulkes NS, Brandstaetter R. Molecular Analysis of Clock Gene Expression in the Avian Brain. Chronobiol Int 2009; 23:113-27. [PMID: 16687285 DOI: 10.1080/07420520500521871] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Birds are equipped with a complex circadian pacemaking system that regulates the rhythmicity of physiology and behavior. As with all organisms, transcriptional and translational feedback loops of clock genes represent the basic molecular mechanism of rhythm generation in birds. To investigate avian clock gene expression, partial cDNA sequences of six mammalian clock gene homologs (Bmal1, Clock, Per2, Per3, Cry1, and Cry2) and a novel avian cryptochrome gene (Cry4) were cloned from the house sparrow, a model system in circadian research. Expression patterns were analyzed by semi-quantitative RT-PCR and RNase protection assays using total RNA extracted from adult male house sparrow brains. With the exception of Cry4, pronounced rhythmic mRNA expression of all the clock genes analyzed was encountered, with mRNA levels varying considerably between the various genes. Although some basic features of the molecular circadian feedback loop appear to be similar between mammals and birds, the precise phase relationships of the clock gene mRNA rhythms relative to each other and to the light zeitgeber differ significantly between the house sparrow and mammals. Our results point to the existence of differences in the organization of avian and mammalian circadian clock mechanisms.
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Affiliation(s)
- Gisela Helfer
- Biological Rhythms Research Group, School of Biosciences, University of Birmingham, UK
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Paulose JK, Peters JL, Karaganis SP, Cassone VM. Pineal melatonin acts as a circadian zeitgeber and growth factor in chick astrocytes. J Pineal Res 2009; 46:286-94. [PMID: 19196435 PMCID: PMC2674028 DOI: 10.1111/j.1600-079x.2008.00659.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Melatonin is rhythmically synthesized and released by the avian pineal gland and retina during the night, targeting an array of tissues and affecting a variety of physiological and behavioral processes. Among these targets, astrocytes express two melatonin receptor subtypes in vitro, the Mel(1A) and Mel(1C) receptors, which play a role in regulating metabolic activity and calcium homeostasis in these cells. Molecular characterization of chick astrocytes has revealed the expression of orthologs of the mammalian clock genes including clock, cry1, cry2, per2, and per3. To test the hypothesis that pineal melatonin entrains molecular clockworks in downstream cells, we asked whether coculturing astrocytes with pinealocytes or administration of exogenous melatonin cycles would entrain metabolic rhythms of 2-deoxy [14C]-glucose (2DG] uptake and/or clock gene expression in cultured astrocytes. Rhythmic secretion of melatonin from light-entrained pinealocytes in coculture as well as cyclic administration of exogenous melatonin entrained rhythms of 2DG uptake and expression of Gallus per2 (gper2) and/or gper3, but not of gcry1 mRNA. Surprisingly, melatonin also caused a dose-dependent increase in mitotic activity of astrocytes, both in coculture and when administered exogenously. The observation that melatonin stimulates mitotic activity in diencephalic astrocytes suggests a trophic role of the hormone in brain development. The data suggest a dual role for melatonin in avian astrocytes: synchronization of rhythmic processes in these cells and regulation of growth and differentiation. These two processes may or may not be mutually exclusive.
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Affiliation(s)
| | - Jennifer L. Peters
- Department of Biochemistry and Molecular Biology, University of Kansas School of Medicine, Kansas City, Kansas
| | | | - Vincent M. Cassone
- Department of Biology, Texas A&M University, College Station, Texas
- Department of Biology, University of Kentucky, Lexington, Kentucky, USA
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Abstract
Daily rhythms are a ubiquitous feature of living systems. Generally, these rhythms are not just passive consequences of cyclic fluctuations in the environment, but instead originate within the organism. In mammals, including humans, the master pacemaker controlling 24-hour rhythms is localized in the suprachiasmatic nuclei of the hypothalamus. This circadian clock is responsible for the temporal organization of a wide variety of functions, ranging from sleep and food intake, to physiological measures such as body temperature, heart rate and hormone release. The retinal circadian clock was the first extra-SCN circadian oscillator to be discovered in mammals and several studies have now demonstrated that many of the physiological, cellular and molecular rhythms that are present within the retina are under the control of a retinal circadian clock, or more likely a network of hierarchically organized circadian clocks that are present within this tissue. BioEssays 30:624-633, 2008. (c) 2008 Wiley Periodicals, Inc.
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Affiliation(s)
- Gianluca Tosini
- Circadian Rhythms and Sleep Disorders Program, Neuroscience Institute. Morehouse School of Medicine, Atlanta, GA, USA.
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48
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Different responses in two strains of chickens (Gallus gallus) in a magnetic orientation test. Anim Cogn 2008; 11:547-52. [PMID: 18297318 DOI: 10.1007/s10071-008-0147-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 02/09/2008] [Accepted: 02/11/2008] [Indexed: 10/22/2022]
Abstract
Previous studies demonstrated that layer strain domestic chicks bred for egg production can orient using directional cues from the magnetic field; here we report that chicks from a broiler strain bred for meat production do not use magnetic cues for orientation. We imprinted both strains of chicken on a red ball and subsequently trained them in a featureless testing arena. Between rewarded trials in the geomagnetic field, we inserted unrewarded tests under the following conditions: (1) in the geomagnetic field, (2) in a magnetic field with North shifted by 90 degrees and (3) in a magnetic field with the inclination inverted. The layer chicks made a correct axial response in 75-80% of the tests, shifting their choices following a rotation of magnetic North. Chicks of the broiler strain, in contrast, performed at chance level with between 47 and 60% of choices on the correct axis. This difference between the strains does not appear to be due to substantial strain differences in motivation to perform the task. It therefore appears possible that the selection of the broiler strain has led to the elimination of the specific ability to respond to magnetic cues in the test situation.
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Nagy AD, Csernus VJ. The role of PACAP in the control of circadian expression of clock genes in the chicken pineal gland. Peptides 2007; 28:1767-74. [PMID: 17716782 DOI: 10.1016/j.peptides.2007.07.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2007] [Revised: 07/10/2007] [Accepted: 07/12/2007] [Indexed: 11/24/2022]
Abstract
Several features of the molecular circadian oscillator of the chicken pineal gland show homology with those in the mammalian SCN. Studies have shown the effects of PACAP on the mammalian SCN, but its effects on the expression of clock genes in the avian pineal gland have not yet been demonstrated. Clock and Cry1 expression was analyzed in pineal glands of chicken embryos after exposure to PACAP-38 in vitro. PACAP reduced expression of both clock genes within 2h. Ten hours after exposure, mRNA contents exceeded that of the controls. Our results support the hypothesis that the molecular clock machinery in the chicken pineal gland is also sensitive to PACAP.
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Affiliation(s)
- András D Nagy
- Department of Anatomy, Medical School, University of Pécs, H-7624 Pécs, Szigeti út 12, Hungary
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Lundmark PO, Pandi-Perumal SR, Srinivasan V, Cardinali DP. Role of melatonin in the eye and ocular dysfunctions. Vis Neurosci 2007; 23:853-62. [PMID: 17266777 DOI: 10.1017/s0952523806230189] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2006] [Accepted: 08/02/2006] [Indexed: 12/15/2022]
Abstract
Melatonin is a ubiquitous molecule and widely distributed in nature, with functional activity occurring in unicellular organisms, plants, fungi, and animals. Several studies have indicated that melatonin synthesis occurs in the retina of most vertebrates, including mammals. The retinal biosynthesis of melatonin and the mechanisms involved in the regulation of this process have been extensively studied. Circadian clocks located in the photoreceptors and retinal neurons regulate melatonin synthesis in the eye. Photoreceptors, dopaminergic amacrine neurons, and horizontal cells of the retina, corneal epithelium, stroma endothelium, and the sclera all have melatonin receptors, indicating a widespread ocular function for melatonin. In addition, melatonin is an effective antioxidant which scavenges free radicals and up-regulates several antioxidant enzymes. It also has a strong antiapoptotic signaling function, an effect that it exerts even during ischemia. Melatonin cytoprotective properties may have practical implications in the treatment of ocular diseases, like glaucoma and age-related macular degeneration.
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Affiliation(s)
- Per O Lundmark
- Department of Optometry and Vision Sciences, Buskerud University College, Kongsberg, Norway
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