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Günther A, Haverkamp S, Irsen S, Watkins PV, Dedek K, Mouritsen H, Briggman KL. Species-specific circuitry of double cone photoreceptors in two avian retinas. Commun Biol 2024; 7:992. [PMID: 39143253 PMCID: PMC11325025 DOI: 10.1038/s42003-024-06697-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Accepted: 08/07/2024] [Indexed: 08/16/2024] Open
Abstract
In most avian retinas, double cones (consisting of a principal and accessory member) outnumber other photoreceptor types and have been associated with various functions, such as encoding luminance, sensing polarized light, and magnetoreception. However, their down-stream circuitry is poorly understood, particularly across bird species. Analysing species differences is important to understand changes in circuitry driven by ecological adaptations. We compare the ultrastructure of double cones and their postsynaptic bipolar cells between a night-migratory European robin and non-migratory chicken. We discover four previously unidentified bipolar cell types in the European robin retina, including midget-like bipolar cells mainly connected to one principal member. A downstream ganglion cell reveals a complete midget-like circuit similar to a circuit in the peripheral primate retina. Additionally, we identify a selective circuit transmitting information from a specific subset of accessory members. Our data highlight species-specific differences in double cone to bipolar cell connectivity, potentially reflecting ecological adaptations.
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Affiliation(s)
- Anja Günther
- Department of Computational Neuroethology, Max Planck Institute for Neurobiology of Behavior-caesar, Bonn, Germany.
| | - Silke Haverkamp
- Department of Computational Neuroethology, Max Planck Institute for Neurobiology of Behavior-caesar, Bonn, Germany
| | - Stephan Irsen
- Electron Microscopy and Analytics, Max Planck Institute for Neurobiology of Behavior-caesar, Bonn, Germany
| | - Paul V Watkins
- Department of Computational Neuroethology, Max Planck Institute for Neurobiology of Behavior-caesar, Bonn, Germany
| | - Karin Dedek
- Animal Navigation/Neurosensorics Group, Institute for Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße 9-11, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, Oldenburg, Germany
| | - Henrik Mouritsen
- Animal Navigation/Neurosensorics Group, Institute for Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Straße 9-11, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, Oldenburg, Germany
| | - Kevin L Briggman
- Department of Computational Neuroethology, Max Planck Institute for Neurobiology of Behavior-caesar, Bonn, Germany.
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2
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Cervino NG, Elias-Costa AJ, Iglesias PP, Yovanovich CAM, Faivovich J. Insights into the evolution of photoreceptor oil droplets in frogs and toads. Proc Biol Sci 2024; 291:20241388. [PMID: 39079666 PMCID: PMC11288682 DOI: 10.1098/rspb.2024.1388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 06/23/2024] [Accepted: 07/02/2024] [Indexed: 08/03/2024] Open
Abstract
Photoreceptor oil droplets (ODs) are spherical organelles placed most commonly within the inner segment of the cone photoreceptors. Comprising neutral lipids, ODs can be either non-pigmented or pigmented and have been considered optically functional in various studies. Among living amphibians, ODs were only reported to occur in frogs and toads (Anura), while they are absent in salamanders and caecilians. Nonetheless, the limited understanding of their taxonomic distribution in anurans impedes a comprehensive assessment of their evolution and relationship with visual ecology. We studied the retinae of 134 anuran species, extending the knowledge of the distribution of ODs to 46 of the 58 currently recognized families, and providing a new perspective on this group that complements the available information from other vertebrates. The occurrence of ODs in anurans shows a strong phylogenetic signal, and our findings revealed that ODs evolved at least six times during the evolutionary history of the group, independently from other vertebrates. Although no evident correlation was found between OD occurrence, adult habits and diel activity, it is inferred that each independent origin involves distinct scenarios in the evolution of ODs concerning photic habits. Furthermore, our results revealed significant differences in the size of the ODs between nocturnal and arrhythmic anurans relative to the length of the cones' outer segment.
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Affiliation(s)
- Nadia G. Cervino
- División Herpetología, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’ – CONICET, Av. Ángel Gallardo 470, Buenos AiresC1405DJR, Argentina
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos AiresC1428EGA, Argentina
| | - Agustín J. Elias-Costa
- División Herpetología, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’ – CONICET, Av. Ángel Gallardo 470, Buenos AiresC1405DJR, Argentina
- Museum für Naturkunde – Leibniz Institute for Evolution and Biodiversity Science, Invalidenstraße 43, Berlin10115, Germany
| | - Patricia P. Iglesias
- CONICET--Agencia INTA General Acha, Estación Experimental Anguil, Avellaneda 530 General Acha, La PampaL8200AEL, Argentina
| | - Carola A. M. Yovanovich
- Department of Zoology, Institute of Biosciences, University of São Paulo, Rua do Matão No. 101, São Paulo05508-090, Brazil
- Department of Biology, Lund University, Sölvegatan 35, Lund22362, Sweden
| | - Julián Faivovich
- División Herpetología, Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’ – CONICET, Av. Ángel Gallardo 470, Buenos AiresC1405DJR, Argentina
- Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos AiresC1428EGA, Argentina
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3
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Baden T. Ancestral photoreceptor diversity as the basis of visual behaviour. Nat Ecol Evol 2024; 8:374-386. [PMID: 38253752 DOI: 10.1038/s41559-023-02291-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 11/10/2023] [Indexed: 01/24/2024]
Abstract
Animal colour vision is based on comparing signals from different photoreceptors. It is generally assumed that processing different spectral types of photoreceptor mainly serves colour vision. Here I propose instead that photoreceptors are parallel feature channels that differentially support visual-motor programmes like motion vision behaviours, prey capture and predator evasion. Colour vision may have emerged as a secondary benefit of these circuits, which originally helped aquatic vertebrates to visually navigate and segment their underwater world. Specifically, I suggest that ancestral vertebrate vision was built around three main systems, including a high-resolution general purpose greyscale system based on ancestral red cones and rods to mediate visual body stabilization and navigation, a high-sensitivity specialized foreground system based on ancestral ultraviolet cones to mediate threat detection and prey capture, and a net-suppressive system based on ancestral green and blue cones for regulating red/rod and ultraviolet circuits. This ancestral strategy probably still underpins vision today, and different vertebrate lineages have since adapted their original photoreceptor circuits to suit their diverse visual ecologies.
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Affiliation(s)
- Tom Baden
- University of Sussex, Sussex Neuroscience, Sussex Center for Sensory Neuroscience and Computation, Brighton, UK.
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4
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Abstract
When vertebrates first conquered the land, they encountered a visual world that was radically distinct from that of their aquatic ancestors. Fish exploit the strong wavelength-dependent interactions of light with water by differentially feeding the signals from up to 5 spectral photoreceptor types into distinct behavioural programmes. However, above the water the same spectral rules do not apply, and this called for an update to visual circuit strategies. Early tetrapods soon evolved the double cone, a still poorly understood pair of new photoreceptors that brought the "ancestral terrestrial" complement from 5 to 7. Subsequent nonmammalian lineages differentially adapted this highly parallelised retinal input strategy for their diverse visual ecologies. By contrast, mammals shed most ancestral photoreceptors and converged on an input strategy that is exceptionally general. In eutherian mammals including in humans, parallelisation emerges gradually as the visual signal traverses the layers of the retina and into the brain.
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Affiliation(s)
- Tom Baden
- University of Sussex, Sussex Neuroscience, Sussex Center for Sensory Neuroscience and Computation, Brighton, United Kingdom
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5
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Hill GE, Weaver RJ, Powers MJ. Carotenoid ornaments and the spandrels of physiology: a critique of theory to explain condition dependency. Biol Rev Camb Philos Soc 2023; 98:2320-2332. [PMID: 37563787 DOI: 10.1111/brv.13008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/12/2023]
Abstract
Even as numerous studies have documented that the red and yellow coloration resulting from the deposition of carotenoids serves as an honest signal of condition, the evolution of condition dependency is contentious. The resource trade-off hypothesis proposes that condition-dependent honest signalling relies on a trade-off of resources between ornamental display and body maintenance. By this model, condition dependency can evolve through selection for a re-allocation of resources to promote ornament expression. By contrast, the index hypothesis proposes that selection focuses mate choice on carotenoid coloration that is inherently condition dependent because production of such coloration is inexorably tied to vital cellular processes. These hypotheses for the origins of condition dependency make strongly contrasting and testable predictions about ornamental traits. To assess these two models, we review the mechanisms of production of carotenoids, patterns of condition dependency involving different classes of carotenoids, and patterns of behavioural responses to carotenoid coloration. We review evidence that traits can be condition dependent without the influence of sexual selection and that novel traits can show condition-dependent expression as soon as they appear in a population, without the possibility of sexual selection. We conclude by highlighting new opportunities for studying condition-dependent signalling made possible by genetic manipulation and expression of ornamental traits in synthetic biological systems.
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Affiliation(s)
- Geoffrey E Hill
- Department of Biological Sciences, 120 W. Samford Avenue, Auburn University, Auburn, AL, 36849, USA
| | - Ryan J Weaver
- Department of Ecology, Evolution, and Organismal Biology, 2200 Osborne Drive, Iowa State University, Ames, IA, USA
| | - Matthew J Powers
- Department of Integrative Biology, 4575 SW Research Way, Oregon State University, Corvallis, OR, 97331, USA
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6
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Pan H, Qin Y, Zhu J, Wang W, Liu Z, Huang X, Lam SM, Shui G, Wang Y, Jiang Y, Huang X. Centrins control chicken cone cell lipid droplet dynamics through lipid-droplet-localized SPDL1. Dev Cell 2023; 58:2528-2544.e8. [PMID: 37699389 DOI: 10.1016/j.devcel.2023.08.012] [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: 07/30/2022] [Revised: 05/10/2023] [Accepted: 08/08/2023] [Indexed: 09/14/2023]
Abstract
As evolutionarily conserved organelles, lipid droplets (LDs) carry out numerous functions and have various subcellular localizations in different cell types and species. In avian cone cells, there is a single apically localized LD. We demonstrated that CIDEA (cell death inducing DFFA like effector a) and microtubules promote the formation of the single LD in chicken cone cells. Centrins, which are well-known centriole proteins, target to the cone cell LD via their C-terminal calcium-binding domains. Centrins localize on cone cell LDs with the help of SPDL1-L (spindle apparatus coiled-coil protein 1-L), a previously uncharacterized isoform of the kinetochore-associated dynein adaptor SPDL1. The loss of CETN3 or overexpression of a truncated CETN1 abrogates the apical localization of the cone cell LD. Simulation analysis showed that multiple LDs or a single mispositioned LD reduces the light sensitivity. Collectively, our findings identify a role of centrins in the regulation of cone cell LD localization, which is important for the light sensitivity of cone cells.
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Affiliation(s)
- Huimin Pan
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yaqiang Qin
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinglin Zhu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhonghua Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiahe Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guanghou Shui
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yuqiang Jiang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China; Tianjian Laboratory of Advanced Biomedical Sciences, Zhengzhou 450001, China.
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7
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Wan YC, Navarrete Méndez MJ, O'Connell LA, Uricchio LH, Roland AB, Maan ME, Ron SR, Betancourth-Cundar M, Pie MR, Howell KA, Richards-Zawacki CL, Cummings ME, Cannatella DC, Santos JC, Tarvin RD. Selection on Visual Opsin Genes in Diurnal Neotropical Frogs and Loss of the SWS2 Opsin in Poison Frogs. Mol Biol Evol 2023; 40:msad206. [PMID: 37791477 PMCID: PMC10548314 DOI: 10.1093/molbev/msad206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023] Open
Abstract
Amphibians are ideal for studying visual system evolution because their biphasic (aquatic and terrestrial) life history and ecological diversity expose them to a broad range of visual conditions. Here, we evaluate signatures of selection on visual opsin genes across Neotropical anurans and focus on three diurnal clades that are well-known for the concurrence of conspicuous colors and chemical defense (i.e., aposematism): poison frogs (Dendrobatidae), Harlequin toads (Bufonidae: Atelopus), and pumpkin toadlets (Brachycephalidae: Brachycephalus). We found evidence of positive selection on 44 amino acid sites in LWS, SWS1, SWS2, and RH1 opsin genes, of which one in LWS and two in RH1 have been previously identified as spectral tuning sites in other vertebrates. Given that anurans have mostly nocturnal habits, the patterns of selection revealed new sites that might be important in spectral tuning for frogs, potentially for adaptation to diurnal habits and for color-based intraspecific communication. Furthermore, we provide evidence that SWS2, normally expressed in rod cells in frogs and some salamanders, has likely been lost in the ancestor of Dendrobatidae, suggesting that under low-light levels, dendrobatids have inferior wavelength discrimination compared to other frogs. This loss might follow the origin of diurnal activity in dendrobatids and could have implications for their behavior. Our analyses show that assessments of opsin diversification in across taxa could expand our understanding of the role of sensory system evolution in ecological adaptation.
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Affiliation(s)
- Yin Chen Wan
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, Dublin, Ireland
| | - María José Navarrete Méndez
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
- Museo de Zoología, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | | | - Lawrence H Uricchio
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
- Department of Biology, Tufts University, Medford, MA, USA
| | - Alexandre-Benoit Roland
- FAS Center for Systems Biology, Harvard University, Cambridge, MA, USA
- Research Centre on Animal Cognition (CRCA), Centre for Integrative Biology (CBI), UMR5169 CNRS, Toulouse University, Toulouse, France
| | - Martine E Maan
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - Santiago R Ron
- Museo de Zoología, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | | | - Marcio R Pie
- Department of Zoology, Universidade Federal do Paraná, Curitiba, Brazil
- Biology Department, Edge Hill University, Ormskirk, United Kingdom
| | - Kimberly A Howell
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Molly E Cummings
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
| | - David C Cannatella
- Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA
- Biodiversity Center, University of Texas at Austin, Austin, TX, USA
| | - Juan C Santos
- Department of Biological Sciences, St. John's University, New York City, NY, USA
| | - Rebecca D Tarvin
- Museum of Vertebrate Zoology and Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
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8
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Nishida Y, Berg PC, Shakersain B, Hecht K, Takikawa A, Tao R, Kakuta Y, Uragami C, Hashimoto H, Misawa N, Maoka T. Astaxanthin: Past, Present, and Future. Mar Drugs 2023; 21:514. [PMID: 37888449 PMCID: PMC10608541 DOI: 10.3390/md21100514] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/18/2023] [Accepted: 09/22/2023] [Indexed: 10/28/2023] Open
Abstract
Astaxanthin (AX), a lipid-soluble pigment belonging to the xanthophyll carotenoids family, has recently garnered significant attention due to its unique physical properties, biochemical attributes, and physiological effects. Originally recognized primarily for its role in imparting the characteristic red-pink color to various organisms, AX is currently experiencing a surge in interest and research. The growing body of literature in this field predominantly focuses on AXs distinctive bioactivities and properties. However, the potential of algae-derived AX as a solution to various global environmental and societal challenges that threaten life on our planet has not received extensive attention. Furthermore, the historical context and the role of AX in nature, as well as its significance in diverse cultures and traditional health practices, have not been comprehensively explored in previous works. This review article embarks on a comprehensive journey through the history leading up to the present, offering insights into the discovery of AX, its chemical and physical attributes, distribution in organisms, and biosynthesis. Additionally, it delves into the intricate realm of health benefits, biofunctional characteristics, and the current market status of AX. By encompassing these multifaceted aspects, this review aims to provide readers with a more profound understanding and a robust foundation for future scientific endeavors directed at addressing societal needs for sustainable nutritional and medicinal solutions. An updated summary of AXs health benefits, its present market status, and potential future applications are also included for a well-rounded perspective.
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Affiliation(s)
- Yasuhiro Nishida
- Fuji Chemical Industries, Co., Ltd., 55 Yokohoonji, Kamiich-machi, Nakaniikawa-gun, Toyama 930-0405, Japan
| | | | - Behnaz Shakersain
- AstaReal AB, Signum, Forumvägen 14, Level 16, 131 53 Nacka, Sweden; (P.C.B.); (B.S.)
| | - Karen Hecht
- AstaReal, Inc., 3 Terri Lane, Unit 12, Burlington, NJ 08016, USA;
| | - Akiko Takikawa
- First Department of Internal Medicine, Faculty of Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan;
| | - Ruohan Tao
- Graduate School of Science and Technology, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda 669-1330, Japan; (R.T.); (Y.K.); (C.U.); (H.H.)
| | - Yumeka Kakuta
- Graduate School of Science and Technology, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda 669-1330, Japan; (R.T.); (Y.K.); (C.U.); (H.H.)
| | - Chiasa Uragami
- Graduate School of Science and Technology, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda 669-1330, Japan; (R.T.); (Y.K.); (C.U.); (H.H.)
| | - Hideki Hashimoto
- Graduate School of Science and Technology, Kwansei Gakuin University, 1 Gakuen-Uegahara, Sanda 669-1330, Japan; (R.T.); (Y.K.); (C.U.); (H.H.)
| | - Norihiko Misawa
- Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Suematsu, Nonoichi-shi 921-8836, Japan;
| | - Takashi Maoka
- Research Institute for Production Development, 15 Shimogamo-morimoto-cho, Sakyo-ku, Kyoto 606-0805, Japan
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9
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Seifert M, Roberts PA, Kafetzis G, Osorio D, Baden T. Birds multiplex spectral and temporal visual information via retinal On- and Off-channels. Nat Commun 2023; 14:5308. [PMID: 37652912 PMCID: PMC10471707 DOI: 10.1038/s41467-023-41032-z] [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: 12/01/2022] [Accepted: 08/18/2023] [Indexed: 09/02/2023] Open
Abstract
In vertebrate vision, early retinal circuits divide incoming visual information into functionally opposite elementary signals: On and Off, transient and sustained, chromatic and achromatic. Together these signals can yield an efficient representation of the scene for transmission to the brain via the optic nerve. However, this long-standing interpretation of retinal function is based on mammals, and it is unclear whether this functional arrangement is common to all vertebrates. Here we show that male poultry chicks use a fundamentally different strategy to communicate information from the eye to the brain. Rather than using functionally opposite pairs of retinal output channels, chicks encode the polarity, timing, and spectral composition of visual stimuli in a highly correlated manner: fast achromatic information is encoded by Off-circuits, and slow chromatic information overwhelmingly by On-circuits. Moreover, most retinal output channels combine On- and Off-circuits to simultaneously encode, or multiplex, both achromatic and chromatic information. Our results from birds conform to evidence from fish, amphibians, and reptiles which retain the full ancestral complement of four spectral types of cone photoreceptors.
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Affiliation(s)
- Marvin Seifert
- School of Life Sciences, University of Sussex, Brighton, UK.
| | - Paul A Roberts
- School of Life Sciences, University of Sussex, Brighton, UK
| | | | - Daniel Osorio
- School of Life Sciences, University of Sussex, Brighton, UK.
| | - Tom Baden
- School of Life Sciences, University of Sussex, Brighton, UK.
- Institute of Ophthalmic Research, University of Tübingen, Tübingen, Germany.
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10
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Hadden PW, Zhang J. An Overview of the Penguin Visual System. Vision (Basel) 2023; 7:vision7010006. [PMID: 36810310 PMCID: PMC9944954 DOI: 10.3390/vision7010006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 01/03/2023] [Accepted: 01/13/2023] [Indexed: 01/20/2023] Open
Abstract
Penguins require vision that is adequate for both subaerial and submarine environments under a wide range of illumination. Here we provide a structured overview of what is known about their visual system with an emphasis on how and how well they achieve these goals. Amphibious vision is facilitated by a relatively flat cornea, the power in air varying from 10.2 dioptres (D) to 41.3 D depending on the species, and there is good evidence for emmetropia both above and below water. All penguins are trichromats with loss of rhodopsin 2, a nocturnal feature, but only deeper diving penguins have been noted to have pale oil droplets and a preponderance of rods. Conversely, the diurnal, shallow-diving little penguin has a higher ganglion cell density (28,867 cells/mm2) and f-number (3.5) than those that operate in dimmer light. In most species studied, there is some binocular overlap, but this reduces upon submergence. However, gaps in our knowledge remain, particularly with regard to the mechanism of accommodation, spectral transmission, behavioural measurements of visual function in low light, and neural adaptations to low light. The rarer species also deserve more attention.
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11
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Corredor VH, Hauzman E, Gonçalves ADS, Ventura DF. Genetic characterization of the visual pigments of the red-eared turtle (Trachemys scripta elegans) and computational predictions of the spectral sensitivity. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2022. [DOI: 10.1016/j.jpap.2022.100141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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12
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Bandara S, von Lintig J. Aster la vista: Unraveling the biochemical basis of carotenoid homeostasis in the human retina. Bioessays 2022; 44:e2200133. [PMID: 36127289 PMCID: PMC10044510 DOI: 10.1002/bies.202200133] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 11/10/2022]
Abstract
Carotenoids play pivotal roles in vision as light filters and precursor of chromophore. Many vertebrates also display the colorful pigments as ornaments in bare skin parts and feathers. Proteins involved in the transport and metabolism of these lipids have been identified including class B scavenger receptors and carotenoid cleavage dioxygenases. Recent research implicates members of the Aster protein family, also known as GRAM domain-containing (GRAMD), in carotenoid metabolism. These multi-domain proteins facilitate the intracellular movement of carotenoids from their site of cellular uptake by scavenger receptors to the site of their metabolic processing by carotenoid cleavage dioxygenases. We provide a model how the coordinated interplay of these proteins and their differential expression establishes carotenoid distribution patterns and function in tissues, with particular emphasis on the human retina.
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Affiliation(s)
- Sepalika Bandara
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Johannes von Lintig
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
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13
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Toomey MB, Marques CI, Araújo PM, Huang D, Zhong S, Liu Y, Schreiner GD, Myers CA, Pereira P, Afonso S, Andrade P, Gazda MA, Lopes RJ, Viegas I, Koch RE, Haynes ME, Smith DJ, Ogawa Y, Murphy D, Kopec RE, Parichy DM, Carneiro M, Corbo JC. A mechanism for red coloration in vertebrates. Curr Biol 2022; 32:4201-4214.e12. [PMID: 36049480 PMCID: PMC9588406 DOI: 10.1016/j.cub.2022.08.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/19/2022] [Accepted: 08/08/2022] [Indexed: 12/14/2022]
Abstract
Red coloration is a salient feature of the natural world. Many vertebrates produce red color by converting dietary yellow carotenoids into red ketocarotenoids via an unknown mechanism. Here, we show that two enzymes, cytochrome P450 2J19 (CYP2J19) and 3-hydroxybutyrate dehydrogenase 1-like (BDH1L), are sufficient to catalyze this conversion. In birds, both enzymes are expressed at the sites of ketocarotenoid biosynthesis (feather follicles and red cone photoreceptors), and genetic evidence implicates these enzymes in yellow/red color variation in feathers. In fish, the homologs of CYP2J19 and BDH1L are required for ketocarotenoid production, and we show that these enzymes are sufficient to produce ketocarotenoids in cell culture and when ectopically expressed in fish skin. Finally, we demonstrate that the red-cone-enriched tetratricopeptide repeat protein 39B (TTC39B) enhances ketocarotenoid production when co-expressed with CYP2J19 and BDH1L. The discovery of this mechanism of ketocarotenoid biosynthesis has major implications for understanding the evolution of color diversity in vertebrates.
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Affiliation(s)
- Matthew B Toomey
- Department of Biological Science, University of Tulsa, Tulsa, OK, USA.
| | - Cristiana I Marques
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Pedro M Araújo
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal; University of Coimbra, MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, Coimbra, Portugal
| | - Delai Huang
- Department of Biology and Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Siqiong Zhong
- Program in Human Nutrition, Department of Human Sciences, Ohio State University, Columbus, OH, USA
| | - Yu Liu
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Gretchen D Schreiner
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Connie A Myers
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Paulo Pereira
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal; Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Sandra Afonso
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
| | - Pedro Andrade
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal
| | - Małgorzata A Gazda
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal
| | - Ricardo J Lopes
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal; MHNC-UP, Natural History and Science Museum of the University of Porto, Porto, Portugal
| | - Ivan Viegas
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Coimbra, Portugal
| | - Rebecca E Koch
- Department of Biological Science, University of Tulsa, Tulsa, OK, USA
| | - Maureen E Haynes
- Department of Biological Science, University of Tulsa, Tulsa, OK, USA
| | - Dustin J Smith
- Department of Biological Science, University of Tulsa, Tulsa, OK, USA
| | - Yohey Ogawa
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Daniel Murphy
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Rachel E Kopec
- Program in Human Nutrition, Department of Human Sciences, Ohio State University, Columbus, OH, USA
| | - David M Parichy
- Department of Biology and Department of Cell Biology, University of Virginia, Charlottesville, VA, USA
| | - Miguel Carneiro
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO, Universidade do Porto, Vairão, Portugal; BIOPOLIS Program in Genomics, Biodiversity and Land Planning, CIBIO, Vairão, Portugal.
| | - Joseph C Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, USA.
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14
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Baden T, Nilsson DE. Is our retina really upside down? Curr Biol 2022; 32:R300-R303. [PMID: 35413251 DOI: 10.1016/j.cub.2022.02.065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In the vertebrate eye, photoreceptors are covered beneath a thick sheet of neural retina and face away from the light. This seemingly awkward arrangement has led to the popular notion that our retinas are upside down, implying a deep design flaw. Baden and Nilsson argue that, from an evolutionary perspective, an inverted design actually offers many notable benefits that might have never been exploited if things had started off the other way round.
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Affiliation(s)
- Tom Baden
- School of Life Sciences, University of Sussex, Brighton, UK; Institute of Ophthalmic Research, University of Tübingen, Tübingen, Germany.
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15
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Ball JM, Chen S, Li W. Mitochondria in cone photoreceptors act as microlenses to enhance photon delivery and confer directional sensitivity to light. SCIENCE ADVANCES 2022; 8:eabn2070. [PMID: 35235359 PMCID: PMC8890704 DOI: 10.1126/sciadv.abn2070] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 01/03/2022] [Indexed: 05/10/2023]
Abstract
Mammalian photoreceptors aggregate numerous mitochondria, organelles chiefly for energy production, in the ellipsoid region immediately adjacent to the light-sensitive outer segment to support the high metabolic demands of phototransduction. However, these complex, lipid-rich organelles are also poised to affect light passage into the outer segment. Here, we show, via live imaging and simulations, that despite this risk of light scattering or absorption, these tightly packed mitochondria "focus" light for entry into the outer segment and that mitochondrial remodeling affects such light concentration. This "microlens"-like feature of cone mitochondria delivers light with an angular dependence akin to the Stiles-Crawford effect (SCE), providing a simple explanation for this essential visual phenomenon that improves resolution. This new insight into the optical role of mitochondria is relevant for the interpretation of clinical ophthalmological imaging, lending support for the use of SCE as an early diagnostic tool in retinal disease.
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Affiliation(s)
- John M. Ball
- Retinal Neurophysiology Section, National Eye Institute, NIH, Bethesda, MD 20892, USA
| | - Shan Chen
- Retinal Neurophysiology Section, National Eye Institute, NIH, Bethesda, MD 20892, USA
| | - Wei Li
- Corresponding author. (J.M.B.); (W.L.)
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16
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Abstract
Carotenoids constitute an essential dietary component of animals and other non-carotenogenic species which use these pigments in both their modified and unmodified forms. Animals utilize uncleaved carotenoids to mitigate light damage and oxidative stress and to signal fitness and health. Carotenoids also serve as precursors of apocarotenoids including retinol, and its retinoid metabolites, which carry out essential functions in animals by forming the visual chromophore 11-cis-retinaldehyde. Retinoids, such as all-trans-retinoic acid, can also act as ligands of nuclear hormone receptors. The fact that enzymes and biochemical pathways responsible for the metabolism of carotenoids in animals bear resemblance to the ones in plants and other carotenogenic species suggests an evolutionary relationship. We will explore some of the modes of transmission of carotenoid genes from carotenogenic species to metazoans. This apparent relationship has been successfully exploited in the past to identify and characterize new carotenoid and retinoid modifying enzymes. We will review approaches used to identify putative animal carotenoid enzymes, and we will describe methods used to functionally validate and analyze the biochemistry of carotenoid modifying enzymes encoded by animals.
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Affiliation(s)
- Alexander R Moise
- Northern Ontario School of Medicine, Sudbury, ON, Canada; Department of Chemistry and Biochemistry, Biology and Biomolecular Sciences Program, Laurentian University, Sudbury, ON, Canada.
| | - Sepalika Bandara
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Johannes von Lintig
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
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17
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Victory N, Segovia Y, García M. Cone distribution and visual resolution of the yellow-legged gull, Larus michahellis (Naumann, 1840). Anat Histol Embryol 2021; 51:197-214. [PMID: 34939688 DOI: 10.1111/ahe.12779] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 10/21/2021] [Accepted: 11/27/2021] [Indexed: 01/21/2023]
Abstract
The morphological characteristics of the yellow-legged gull's photoreceptors and cone distribution were studied using light and electron microscopy. In wholemount fresh retinas, five different coloured oil droplets located in the cone inner segments could be seen and characterized by colour, diameter and stratification. The photoreceptors were classified by comparing the fresh and fixed vertical sections under a light and electron microscope. Rods were easily distinguished from cones based on the outer segment morphology and the absence of oil droplets in their inner segments. Four types of single cones were associated with red, yellow, colourless and transparent oil droplets. Unequal double cones comprised a long principal member with a green oil droplet and an accessory short member containing a green microdroplet which was highly electron-dense under electron microscopy. The different types of oil droplets were counted from microphotographs of fresh retinal samples in 20 regions. The density, percentage and diameter of the oil droplets were determined. The results showed that central regions had the highest oil droplet density which decreased towards the retinal periphery in all quadrants. Moreover, the oil droplet density was higher in the dorsotemporal quadrant than in other retinal regions. The average density of the red oil droplets was highest in the central areas, whereas colourless oil droplets had the highest density throughout the retina. In contrast, transparent oil droplets had the lowest density across all the regions of the retina. Finally, the retinal resolution was 52.61 cycles/degree. It was calculated using the posterior nodal distance and the oil droplet diameter. The work concludes by discussing the significance of the relative proportion of different cone types across the retina.
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Affiliation(s)
- Noemi Victory
- Department of Biotechnology, Faculty of Science, University of Alicante, Alicante, Spain
| | - Yolanda Segovia
- Department of Biotechnology, Faculty of Science, University of Alicante, Alicante, Spain
| | - Magdalena García
- Department of Biotechnology, Faculty of Science, University of Alicante, Alicante, Spain
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18
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Bertolesi GE, Debnath N, Atkinson-Leadbeater K, Niedzwiecka A, McFarlane S. Distinct type II opsins in the eye decode light properties for background adaptation and behavioural background preference. Mol Ecol 2021; 30:6659-6676. [PMID: 34592025 DOI: 10.1111/mec.16203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/02/2021] [Accepted: 09/10/2021] [Indexed: 12/17/2022]
Abstract
Crypsis increases survival by reducing predator detection. Xenopus laevis tadpoles decode light properties from the substrate to induce two responses: a cryptic coloration response where dorsal skin pigmentation is adjusted to the colour of the substrate (background adaptation) and a behavioural crypsis where organisms move to align with a specific colour surface (background preference). Both processes require organisms to detect reflected light from the substrate. We explored the relationship between background adaptation and preference and the light properties able to trigger both responses. We also analysed which retinal photosensor (type II opsin) is involved. Our results showed that these two processes are segregated mechanistically, as there is no correlation between the preference for a specific background with the level of skin pigmentation, and different dorsal retina-localized type II opsins appear to underlie the two crypsis modes. Indeed, inhibition of melanopsin affects background adaptation but not background preference. Instead, we propose pinopsin is the photosensor involved in background preference. pinopsin mRNA is co-expressed with mRNA for the sws1 cone photopigment in dorsally located photoreceptors. Importantly, the developmental onset of pinopsin expression aligns with the emergence of the preference for a white background, but after the background adaptation phenotype appears. Furthermore, white background preference of tadpoles is associated with increased pinopsin expression, a feature that is lost in premetamorphic froglets along with a preference for a white background. Thus, our data show a mechanistic dissociation between background adaptation and background preference, and we suggest melanopsin and pinopsin, respectively, initiate the two responses.
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Affiliation(s)
- Gabriel E Bertolesi
- Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada.,Department of Cell Biology and Anatomy, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Nilakshi Debnath
- Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada.,Department of Cell Biology and Anatomy, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | | | - Anna Niedzwiecka
- Department of Chemistry, University of Calgary, Calgary, Alberta, Canada
| | - Sarah McFarlane
- Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada.,Department of Cell Biology and Anatomy, Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
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19
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Price-Waldman R, Stoddard MC. Avian Coloration Genetics: Recent Advances and Emerging Questions. J Hered 2021; 112:395-416. [PMID: 34002228 DOI: 10.1093/jhered/esab015] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/22/2021] [Indexed: 11/13/2022] Open
Abstract
The colorful phenotypes of birds have long provided rich source material for evolutionary biologists. Avian plumage, beaks, skin, and eggs-which exhibit a stunning range of cryptic and conspicuous forms-inspired early work on adaptive coloration. More recently, avian color has fueled discoveries on the physiological, developmental, and-increasingly-genetic mechanisms responsible for phenotypic variation. The relative ease with which avian color traits can be quantified has made birds an attractive system for uncovering links between phenotype and genotype. Accordingly, the field of avian coloration genetics is burgeoning. In this review, we highlight recent advances and emerging questions associated with the genetic underpinnings of bird color. We start by describing breakthroughs related to 2 pigment classes: carotenoids that produce red, yellow, and orange in most birds and psittacofulvins that produce similar colors in parrots. We then discuss structural colors, which are produced by the interaction of light with nanoscale materials and greatly extend the plumage palette. Structural color genetics remain understudied-but this paradigm is changing. We next explore how colors that arise from interactions among pigmentary and structural mechanisms may be controlled by genes that are co-expressed or co-regulated. We also identify opportunities to investigate genes mediating within-feather micropatterning and the coloration of bare parts and eggs. We conclude by spotlighting 2 research areas-mechanistic links between color vision and color production, and speciation-that have been invigorated by genetic insights, a trend likely to continue as new genomic approaches are applied to non-model species.
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20
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Alaasam VJ, Kernbach ME, Miller CR, Ferguson SM. The diversity of photosensitivity and its implications for light pollution. Integr Comp Biol 2021; 61:1170-1181. [PMID: 34232263 DOI: 10.1093/icb/icab156] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Artificial light at night (ALAN) is a pervasive anthropogenic pollutant, emanating from urban and suburban developments and reaching nearly all ecosystems from dense forests to coastlines. One proposed strategy for attenuating the consequences of ALAN is to modify its spectral composition to forms that are less disruptive for photosensory systems. However, ALAN is a complicated pollutant to manage due to the extensive variation in photosensory mechanisms and the diverse ways these mechanisms manifest in biological and ecological contexts. Here, we highlight the diversity in photosensitivity across taxa and the implications of this diversity in predicting biological responses to different forms of night lighting. We curated this paper to be broadly accessible and inform current decisions about the spectrum of electric lights used outdoors. We advocate that efforts to mitigate light pollution should consider the unique ways species perceive ALAN, as well as how diverse responses to ALAN scale up to produce diverse ecological outcomes.
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Affiliation(s)
- Valentina J Alaasam
- Ecology, Evolution and Conservation Program, University of Nevada, Reno, Reno, NV.,Department of Biology, University of Nevada, Reno, Reno, NV
| | | | - Colleen R Miller
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY
| | - Stephen M Ferguson
- Department of Biology, College of Wooster, Wooster, OH.,Division of Natural Sciences, St. Norbert College, De Pere, WI
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21
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Toomey MB, Ronald KL. Avian color expression and perception: is there a carotenoid link? J Exp Biol 2021; 224:269205. [PMID: 34142139 DOI: 10.1242/jeb.203844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Carotenoids color many of the red, orange and yellow ornaments of birds and also shape avian vision. The carotenoid-pigmented oil droplets in cone photoreceptors filter incoming light and are predicted to aid in color discrimination. Carotenoid use in both avian coloration and color vision raises an intriguing question: is the evolution of visual signals and signal perception linked through these pigments? Here, we explore the genetic, physiological and functional connections between these traits. Carotenoid color and droplet pigmentation share common mechanisms of metabolic conversion and are both affected by diet and immune system challenges. Yet, the time scale and magnitude of these effects differ greatly between plumage and the visual system. Recent observations suggest a link between retinal carotenoid levels and color discrimination performance, but the mechanisms underlying these associations remain unclear. Therefore, we performed a modeling exercise to ask whether and how changes in droplet carotenoid content could alter the perception of carotenoid-based plumage. This exercise revealed that changing oil droplet carotenoid concentration does not substantially affect the discrimination of carotenoid-based colors, but might change how reliably a receiver can predict the carotenoid content of an ornament. These findings suggest that, if present, a carotenoid link between signal and perception is subtle. Deconstructing this relationship will require a deeper understanding of avian visual perception and the mechanisms of color production. We highlight several areas where we see opportunities to gain new insights, including comparative genomic studies of shared mechanisms of carotenoid processing and alternative approaches to investigating color vision.
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Affiliation(s)
- Matthew B Toomey
- Department of Biological Science, University of Tulsa, 800 S Tucker Dr., Tulsa, OK 74104, USA
| | - Kelly L Ronald
- Department of Biology, Hope College, 35 East 12th Street, Holland, MI 49422, USA
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22
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Bennett KFP, Lim HC, Braun MJ. Sexual selection and introgression in avian hybrid zones: Spotlight on Manacus. Integr Comp Biol 2021; 61:1291-1309. [PMID: 34128981 DOI: 10.1093/icb/icab135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Hybrid zones offer a window into the processes and outcomes of evolution, from species formation or fusion to genomic underpinnings of specific traits and isolating mechanisms. Sexual selection is believed to be an important factor in speciation processes, and hybrid zones present special opportunities to probe its impact. The manakins (Aves, Pipridae) are a promising group in which to study the interplay of sexual selection and natural hybridization: they show substantial variation across the family in the strength of sexual selection they experience, they readily hybridize within and between genera, and they appear to have formed hybrid species, a rare event in birds. A hybrid zone between two manakins in the genus Manacus is unusual in that plumage and behavioral traits of one species have introgressed asymmetrically into populations of the second species through positive sexual selection, then apparently stalled at a river barrier. This is one of a handful of documented examples of asymmetric sexual trait introgression with a known selective mechanism. It offers opportunities to examine reproductive isolation, introgression, plumage color evolution, and natural factors enhancing or constraining the effects of sexual selection in real time. Here, we review previous work in this system, propose new hypotheses for observed patterns, and recommend approaches to test them.
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Affiliation(s)
- Kevin F P Bennett
- Behavior, Ecology, Evolution, and Systematics Program, University of Maryland, College Park, MD, USA.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - Haw Chuan Lim
- Department of Biology, George Mason University, Manassas, VA, USA.,Center for Conservation Genomics, Smithsonian Conservation Biology Institute, Washington, DC, USA
| | - Michael J Braun
- Behavior, Ecology, Evolution, and Systematics Program, University of Maryland, College Park, MD, USA.,Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
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23
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Cangiano L, Asteriti S. Interphotoreceptor coupling: an evolutionary perspective. Pflugers Arch 2021; 473:1539-1554. [PMID: 33988778 PMCID: PMC8370920 DOI: 10.1007/s00424-021-02572-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/13/2021] [Accepted: 04/23/2021] [Indexed: 12/16/2022]
Abstract
In the vertebrate retina, signals generated by cones of different spectral preference and by highly sensitive rod photoreceptors interact at various levels to extract salient visual information. The first opportunity for such interaction is offered by electrical coupling of the photoreceptors themselves, which is mediated by gap junctions located at the contact points of specialised cellular processes: synaptic terminals, telodendria and radial fins. Here, we examine the evolutionary pressures for and against interphotoreceptor coupling, which are likely to have shaped how coupling is deployed in different species. The impact of coupling on signal to noise ratio, spatial acuity, contrast sensitivity, absolute and increment threshold, retinal signal flow and colour discrimination is discussed while emphasising available data from a variety of vertebrate models spanning from lampreys to primates. We highlight the many gaps in our knowledge, persisting discrepancies in the literature, as well as some major unanswered questions on the actual extent and physiological role of cone-cone, rod-cone and rod-rod communication. Lastly, we point toward limited but intriguing evidence suggestive of the ancestral form of coupling among ciliary photoreceptors.
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Affiliation(s)
- Lorenzo Cangiano
- Dept. of Translational Research, University of Pisa, Via San Zeno 31, 56123, Pisa, Italy.
| | - Sabrina Asteriti
- Dept. of Translational Research, University of Pisa, Via San Zeno 31, 56123, Pisa, Italy
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24
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Widomska J, Gruszecki WI, Subczynski WK. Factors Differentiating the Antioxidant Activity of Macular Xanthophylls in the Human Eye Retina. Antioxidants (Basel) 2021; 10:601. [PMID: 33919673 PMCID: PMC8070478 DOI: 10.3390/antiox10040601] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 04/01/2021] [Accepted: 04/07/2021] [Indexed: 02/06/2023] Open
Abstract
Macular xanthophylls, which are absorbed from the human diet, accumulate in high concentrations in the human retina, where they efficiently protect against oxidative stress that may lead to retinal damage. In addition, macular xanthophylls are uniquely spatially distributed in the retina. The zeaxanthin concentration (including the lutein metabolite meso-zeaxanthin) is ~9-fold greater than lutein concentration in the central fovea. These numbers do not correlate at all with the dietary intake of xanthophylls, for which there is a dietary zeaxanthin-to-lutein molar ratio of 1:12 to 1:5. The unique spatial distributions of macular xanthophylls-lutein, zeaxanthin, and meso-zeaxanthin-in the retina, which developed during evolution, maximize the protection of the retina provided by these xanthophylls. We will correlate the differences in the spatial distributions of macular xanthophylls with their different antioxidant activities in the retina. Can the major protective function of macular xanthophylls in the retina, namely antioxidant actions, explain their evolutionarily determined, unique spatial distributions? In this review, we will address this question.
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Affiliation(s)
- Justyna Widomska
- Department of Biophysics, Medical University of Lublin, Jaczewskiego 4, 20-090 Lublin, Poland
| | - Wieslaw I. Gruszecki
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland;
| | - Witold K. Subczynski
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA;
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25
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Gazda MA, Toomey MB, Araújo PM, Lopes RJ, Afonso S, Myers CA, Serres K, Kiser PD, Hill GE, Corbo JC, Carneiro M. Genetic Basis of De Novo Appearance of Carotenoid Ornamentation in Bare Parts of Canaries. Mol Biol Evol 2021; 37:1317-1328. [PMID: 31930402 DOI: 10.1093/molbev/msaa006] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Unlike wild and domestic canaries (Serinus canaria), or any of the three dozen species of finches in genus Serinus, the domestic urucum breed of canaries exhibits bright red bills and legs. This novel trait offers a unique opportunity to understand the mechanisms of bare-part coloration in birds. To identify the mutation producing the colorful phenotype, we resequenced the genome of urucum canaries and performed a range of analyses to search for genotype-to-phenotype associations across the genome. We identified a nonsynonymous mutation in the gene BCO2 (beta-carotene oxygenase 2, also known as BCDO2), an enzyme involved in the cleavage and breakdown of full-length carotenoids into short apocarotenoids. Protein structural models and in vitro functional assays indicate that the urucum mutation abrogates the carotenoid-cleavage activity of BCO2. Consistent with the predicted loss of carotenoid-cleavage activity, urucum canaries tended to have increased levels of full-length carotenoid pigments in bill tissue and reduced levels of carotenoid-cleavage products (apocarotenoids) in retinal tissue compared with other breeds of canaries. We hypothesize that carotenoid-based bare-part coloration might be readily gained, modified, or lost through simple switches in the enzymatic activity or regulation of BCO2 and this gene may be an important mediator in the evolution of bare-part coloration among bird species.
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Affiliation(s)
- Małgorzata Anna Gazda
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal.,Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
| | - Matthew B Toomey
- Department of Biological Science, University of Tulsa, Tulsa, OK
| | - Pedro M Araújo
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal.,MARE - Marine and Environmental Sciences Centre, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Ricardo J Lopes
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - Sandra Afonso
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal
| | - Connie A Myers
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Kyla Serres
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Philip D Kiser
- Department of Physiology & Biophysics, School of Medicine, Gillespie Neuroscience Research Facility, University of California, Irvine, Irvine, CA
| | - Geoffrey E Hill
- Department of Biological Sciences, Auburn University, Auburn, AL
| | - Joseph C Corbo
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Miguel Carneiro
- CIBIO/InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Vairão, Portugal.,Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, Porto, Portugal
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Tedore C, Nilsson DE. Ultraviolet vision aids the detection of nutrient-dense non-signaling plant foods. Vision Res 2021; 183:16-29. [PMID: 33639304 DOI: 10.1016/j.visres.2021.01.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 01/10/2021] [Accepted: 01/24/2021] [Indexed: 11/29/2022]
Abstract
To expand our understanding of what tasks are particularly helped by UV vision and may justify the costs of focusing high-energy light onto the retina, we used an avian-vision multispectral camera to image diverse vegetated habitats in search of UV contrasts that differ markedly from visible-light contrasts. One UV contrast that stood out as very different from visible-light contrasts was that of nutrient-dense non-signaling plant foods (such as young leaves and immature fruits) against their natural backgrounds. From our images, we calculated color contrasts between 62+ species of such foods and mature foliage for the two predominant color vision systems of birds, UVS and VS. We also computationally generated images of what a generalized tetrachromat, unfiltered by oil droplets, would see, by developing a new methodology that uses constrained linear least squares to solve for optimal weighted combinations of avian camera filters to mimic new spectral sensitivities. In all visual systems, we found that nutrient-dense non-signaling plant foods presented a lower, often negative figure-ground contrast in the UV channels, and a higher, often positive figure-ground contrast in the visible channels. Although a zero contrast may sound unhelpful, it can actually enhance color contrast when compared in a color opponent system to other channels with nonzero contrasts. Here, low or negative UV contrasts markedly enhanced color contrasts. We propose that plants may struggle to evolve better UV crypsis since UV reflectance from vegetation is largely specular and thus highly dependent on object orientation, shape, and texture.
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Affiliation(s)
- Cynthia Tedore
- Lund Vision Group, Lund University, Sölvegatan 35, 223 62 Lund, Sweden.
| | - Dan-Eric Nilsson
- Lund Vision Group, Lund University, Sölvegatan 35, 223 62 Lund, Sweden
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Sultan AE, Ghoneim AM, El-Gammal HL, El-Bakary NER. Vision adaptation in the laughing dove (Streptopelia senegalensis, Linnaeus, 1766) inferred from structural, ultrastructural, and genetic characterization. J Comp Neurol 2020; 529:1830-1848. [PMID: 33094834 DOI: 10.1002/cne.25059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/12/2020] [Accepted: 10/19/2020] [Indexed: 11/06/2022]
Abstract
Neuroanatomy of the retina reflects adaptation and acclimation for dark and light conditions. Retinal cells and genes must be functionally adjusted to various environmental luminosities. Opsins are brilliant molecules to assess the adaptations at the genetic and phenotypic levels. Photic adaptations may reveal new mechanisms that enhance vision abilities. Through the investigation of histological, ultrastructural constituents of the whole retinal layers, and the sequencing of shortwave length sensitive opsin 1 (SWS1) of the laughing dove (Streptopelia senegalensis), the current study confirms the plasticity of the retina in response to the natural photic conditions. Retinal pigmented epithelium has plentiful melanosomes, signifying a highly adapted eye for maximum light perception and protection. Variously colored oil droplets signify high color vision ability. Stratified outer nuclear layer with many Müller cells suggests high sensitivity to dim conditions and high retinal regeneration. The penetration of outer limiting membrane by photoreceptor nuclei and Müller cell microvilli could minimize the light reflection. Oligodendrocytes establish thick myelination demanded for a keen visual acuity. A functional violet sensitive SWS1 with crucial Ser90 is presumed. Molecular phylogeny showed a secondary loss as color vision was shifted back from ultraviolet (UV) sensitivity to the ancestral avian violet sensitivity, thus improving visual resolution. However, SWS1 has some UV sensitive residues. These findings implicate not only spectral adaptations with high color vision ability and acuity but also photoinduced structural reorganizations. Further studies are needed to assess the secrets between photons and the structural genes.
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Affiliation(s)
- Aya E Sultan
- Zoology Department, Faculty of Science, Damietta University, Damietta, Egypt
| | - Ahmed M Ghoneim
- Zoology Department, Faculty of Science, Damietta University, Damietta, Egypt
| | - Hekmat L El-Gammal
- Zoology Department, Faculty of Science, Damietta University, Damietta, Egypt
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28
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Abstract
For centuries, the eye has fascinated scientists and philosophers alike, and as a result the visual system has always been at the forefront of integrating cutting-edge technology in research. We are again at a turning point at which technical advances have expanded the range of organisms we can study developmentally and deepened what we can learn. In this new era, we are finally able to understand eye development in animals across the phylogenetic tree. In this Review, we highlight six areas in comparative visual system development that address questions that are important for understanding the developmental basis of evolutionary change. We focus on the opportunities now available to biologists to study the developmental genetics, cell biology and morphogenesis that underlie the incredible variation of visual organs found across the Metazoa. Although decades of important work focused on gene expression has suggested homologies and potential evolutionary relationships between the eyes of diverse animals, it is time for developmental biologists to move away from this reductive approach. We now have the opportunity to celebrate the differences and diversity in visual organs found across animal development, and to learn what it can teach us about the fundamental principles of biological systems and how they are built.
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Affiliation(s)
- Kristen M Koenig
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
- John Harvard Distinguished Science Fellowship Program, Harvard University, Cambridge, MA 02138, USA
| | - Jeffrey M Gross
- Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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Lomba E, Weis JJ, Guisández L, Torquato S. Minimal statistical-mechanical model for multihyperuniform patterns in avian retina. Phys Rev E 2020; 102:012134. [PMID: 32794939 DOI: 10.1103/physreve.102.012134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/22/2020] [Indexed: 11/07/2022]
Abstract
Birds are known for their extremely acute sense of vision. The very peculiar structural distribution of five different types of cones in the retina underlies this exquisite ability to sample light. It was recently found that each cone population as well as their total population display a disordered pattern in which long-wavelength density fluctuations vanish [Jiao et al., Phys. Rev. E 89, 022721 (2014)PLEEE81539-375510.1103/PhysRevE.89.022721]. This property, known as hyperuniformity, is also present in perfect crystals. In situations like the avian retina in which both the global structure and that of each component display hyperuniformity, the system is said to be multihyperuniform. In this work, we aim at devising a minimal statistical-mechanical model that can reproduce the main features of the spatial distribution of photoreceptors in avian retina, namely the presence of disorder, multihyperuniformity, and local heterocoordination. This last feature is key to avoiding local clustering of the same type of photoreceptors, an undesirable feature for the efficient sampling of light. For this purpose, we formulate a minimal statistical-mechanical model that definitively exhibits the required structural properties: an equimolar three-component mixture (one component to sample each primary color: red, green, and blue) of nonadditive hard disks to which a long-range logarithmic repulsion is added between like particles. Interestingly, a Voronoi analysis of our idealized system of photoreceptors shows that the space-filling Voronoi polygons display a rather uniform area distribution, symmetrically centered around that of a regular lattice, a structural property also found in human retina. Disordered multihyperuniformity offers an alternative to generate photoreceptor patterns with minimal long-range concentration and density fluctuations. This is the key to overcoming the difficulties in devising an efficient visual system in which crystal-like order is absent.
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Affiliation(s)
- Enrique Lomba
- Instituto de Química Física Rocasolano, CSIC, Calle Serrano 119, E-28006 Madrid, Spain
| | - Jean-Jacques Weis
- Université de Paris-Saclay, Laboratoire de Physique Théorique, Bâtiment 210, 91405 Orsay Cedex, France
| | - Leandro Guisández
- Instituto de Química Física Rocasolano, CSIC, Calle Serrano 119, E-28006 Madrid, Spain.,IFLYSIB (UNLP, CONICET), 59 No. 789, B1900BTE La Plata, Argentina
| | - Salvatore Torquato
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.,Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08544, USA
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Stoddard MC, Eyster HN, Hogan BG, Morris DH, Soucy ER, Inouye DW. Wild hummingbirds discriminate nonspectral colors. Proc Natl Acad Sci U S A 2020; 117:15112-15122. [PMID: 32541035 PMCID: PMC7334476 DOI: 10.1073/pnas.1919377117] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many animals have the potential to discriminate nonspectral colors. For humans, purple is the clearest example of a nonspectral color. It is perceived when two color cone types in the retina (blue and red) with nonadjacent spectral sensitivity curves are predominantly stimulated. Purple is considered nonspectral because no monochromatic light (such as from a rainbow) can evoke this simultaneous stimulation. Except in primates and bees, few behavioral experiments have directly examined nonspectral color discrimination, and little is known about nonspectral color perception in animals with more than three types of color photoreceptors. Birds have four color cone types (compared to three in humans) and might perceive additional nonspectral colors such as UV+red and UV+green. Can birds discriminate nonspectral colors, and are these colors behaviorally and ecologically relevant? Here, using comprehensive behavioral experiments, we show that wild hummingbirds can discriminate a variety of nonspectral colors. We also show that hummingbirds, relative to humans, likely perceive a greater proportion of natural colors as nonspectral. Our analysis of plumage and plant spectra reveals many colors that would be perceived as nonspectral by birds but not by humans: Birds' extra cone type allows them not just to see UV light but also to discriminate additional nonspectral colors. Our results support the idea that birds can distinguish colors throughout tetrachromatic color space and indicate that nonspectral color perception is vital for signaling and foraging. Since tetrachromacy appears to have evolved early in vertebrates, this capacity for rich nonspectral color perception is likely widespread.
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Affiliation(s)
- Mary Caswell Stoddard
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544;
- Rocky Mountain Biological Laboratory, Crested Butte, CO 81224
| | - Harold N Eyster
- Rocky Mountain Biological Laboratory, Crested Butte, CO 81224
- Institute for Resources, Environment and Sustainability, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Benedict G Hogan
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544
- Rocky Mountain Biological Laboratory, Crested Butte, CO 81224
| | - Dylan H Morris
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544
| | - Edward R Soucy
- Center for Brain Science, Harvard University, Cambridge, MA 02138
| | - David W Inouye
- Rocky Mountain Biological Laboratory, Crested Butte, CO 81224
- Department of Biology, University of Maryland, College Park, MD 20742
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Variation in carotenoid-containing retinal oil droplets correlates with variation in perception of carotenoid coloration. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02874-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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32
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Thyroid hormone receptors mediate two distinct mechanisms of long-wavelength vision. Proc Natl Acad Sci U S A 2020; 117:15262-15269. [PMID: 32541022 DOI: 10.1073/pnas.1920086117] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Thyroid hormone (TH) signaling plays an important role in the regulation of long-wavelength vision in vertebrates. In the retina, thyroid hormone receptor β (thrb) is required for expression of long-wavelength-sensitive opsin (lws) in red cone photoreceptors, while in retinal pigment epithelium (RPE), TH regulates expression of a cytochrome P450 enzyme, cyp27c1, that converts vitamin A1 into vitamin A2 to produce a red-shifted chromophore. To better understand how TH controls these processes, we analyzed the phenotype of zebrafish with mutations in the three known TH nuclear receptor transcription factors (thraa, thrab, and thrb). We found that no single TH nuclear receptor is required for TH-mediated induction of cyp27c1 but that deletion of all three (thraa -/- ;thrab -/- ;thrb -/- ) completely abrogates its induction and the resulting conversion of A1- to A2-based retinoids. In the retina, loss of thrb resulted in an absence of red cones at both larval and adult stages without disruption of the underlying cone mosaic. RNA-sequencing analysis revealed significant down-regulation of only five genes in adult thrb -/- retina, of which three (lws1, lws2, and miR-726) occur in a single syntenic cluster. In the thrb -/- retina, retinal progenitors destined to become red cones were transfated into ultraviolet (UV) cones and horizontal cells. Taken together, our findings demonstrate cooperative regulation of cyp27c1 by TH receptors and a requirement for thrb in red cone fate determination. Thus, TH signaling coordinately regulates both spectral sensitivity and sensory plasticity.
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Weber P, Flores RE, Kiefer MF, Schupp M. Retinol Saturase: More than the Name Suggests. Trends Pharmacol Sci 2020; 41:418-427. [PMID: 32345479 DOI: 10.1016/j.tips.2020.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 03/25/2020] [Accepted: 03/30/2020] [Indexed: 12/11/2022]
Abstract
Retinol saturase (RetSat) is an oxidoreductase that is expressed in metabolically active tissues and is highly regulated in conditions related to insulin resistance and type 2 diabetes. Thus far, RetSat has been implicated in adipocyte differentiation, hepatic glucose and lipid metabolism, macrophage function, vision, and the generation of reactive oxygen species (ROS). Although initially described to transform retinol to 13,14-dihydroretinol, a function it was named after, alternative enzymatic reactions may underlie some of these biological effects. We summarize recent findings and identify major obstacles standing in the way of its pharmacological exploitation, how we might overcome these, and discuss the therapeutic potential of modulating the activity of RetSat in alleviating human pathologies.
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Affiliation(s)
- Pamela Weber
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, 10115 Berlin, Germany
| | - Roberto E Flores
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, 10115 Berlin, Germany
| | - Marie F Kiefer
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, 10115 Berlin, Germany
| | - Michael Schupp
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Pharmacology, Center for Cardiovascular Research, 10115 Berlin, Germany.
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34
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Osorio D. The evolutionary ecology of bird and reptile photoreceptor spectral sensitivities. Curr Opin Behav Sci 2019. [DOI: 10.1016/j.cobeha.2019.10.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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35
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36
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Thoreson WB, Dacey DM. Diverse Cell Types, Circuits, and Mechanisms for Color Vision in the Vertebrate Retina. Physiol Rev 2019; 99:1527-1573. [PMID: 31140374 PMCID: PMC6689740 DOI: 10.1152/physrev.00027.2018] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 03/27/2019] [Accepted: 04/02/2019] [Indexed: 01/13/2023] Open
Abstract
Synaptic interactions to extract information about wavelength, and thus color, begin in the vertebrate retina with three classes of light-sensitive cells: rod photoreceptors at low light levels, multiple types of cone photoreceptors that vary in spectral sensitivity, and intrinsically photosensitive ganglion cells that contain the photopigment melanopsin. When isolated from its neighbors, a photoreceptor confounds photon flux with wavelength and so by itself provides no information about color. The retina has evolved elaborate color opponent circuitry for extracting wavelength information by comparing the activities of different photoreceptor types broadly tuned to different parts of the visible spectrum. We review studies concerning the circuit mechanisms mediating opponent interactions in a range of species, from tetrachromatic fish with diverse color opponent cell types to common dichromatic mammals where cone opponency is restricted to a subset of specialized circuits. Distinct among mammals, primates have reinvented trichromatic color vision using novel strategies to incorporate evolution of an additional photopigment gene into the foveal structure and circuitry that supports high-resolution vision. Color vision is absent at scotopic light levels when only rods are active, but rods interact with cone signals to influence color perception at mesopic light levels. Recent evidence suggests melanopsin-mediated signals, which have been identified as a substrate for setting circadian rhythms, may also influence color perception. We consider circuits that may mediate these interactions. While cone opponency is a relatively simple neural computation, it has been implemented in vertebrates by diverse neural mechanisms that are not yet fully understood.
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Affiliation(s)
- Wallace B Thoreson
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center , Omaha, Nebraska ; and Department of Biological Structure, Washington National Primate Research Center, University of Washington , Seattle, Washington
| | - Dennis M Dacey
- Department of Ophthalmology and Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center , Omaha, Nebraska ; and Department of Biological Structure, Washington National Primate Research Center, University of Washington , Seattle, Washington
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37
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Arteni AA, LaFountain AM, Alexandre MTA, Fradot M, Mendes-Pinto MM, Sahel JA, Picaud S, Frank HA, Robert B, Pascal AA. Carotenoid composition and conformation in retinal oil droplets of the domestic chicken. PLoS One 2019; 14:e0217418. [PMID: 31150434 PMCID: PMC6544226 DOI: 10.1371/journal.pone.0217418] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 05/10/2019] [Indexed: 12/21/2022] Open
Abstract
Carotenoid-containing oil droplets in the avian retina act as cut-off filters to enhance colour discrimination. We report a confocal resonance Raman investigation of the oil droplets of the domestic chicken, Gallus gallus domesticus. We show that all carotenoids present are in a constrained conformation, implying a locus in specific lipid binding sites. In addition, we provide proof of a recent conclusion that all carotenoid-containing droplets contain a mixture of all carotenoids present, rather than only a subset of them-a conclusion that diverges from the previously-held view. Our results have implications for the mechanism(s) giving rise to these carotenoid mixtures in the differently-coloured droplets.
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Affiliation(s)
- Ana-Andreea Arteni
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Amy M. LaFountain
- Department of Chemistry, University of Connecticut, Storrs, Connecticut, United States of America
| | - Maxime T. A. Alexandre
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Mathias Fradot
- Sorbonne University, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Maria M. Mendes-Pinto
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - José-Alain Sahel
- Sorbonne University, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Serge Picaud
- Sorbonne University, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Harry A. Frank
- Department of Chemistry, University of Connecticut, Storrs, Connecticut, United States of America
| | - Bruno Robert
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Andrew A. Pascal
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- * E-mail:
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38
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Seasonal pelage color change of two sympatric arboreal squirrel species in the subarctic region. THE EUROPEAN ZOOLOGICAL JOURNAL 2019. [DOI: 10.1080/24750263.2019.1682694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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