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Salgado D, Mariluz BR, Araujo M, Lorena J, Perez LN, Ribeiro RDL, Sousa JDF, Schneider PN. Light-induced shifts in opsin gene expression in the four-eyed fish Anableps anableps. Front Neurosci 2022; 16:995469. [PMID: 36248668 PMCID: PMC9556854 DOI: 10.3389/fnins.2022.995469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/08/2022] [Indexed: 11/13/2022] Open
Abstract
The development of the vertebrate eye is a complex process orchestrated by several conserved transcriptional and signaling regulators. Aside from partial or complete loss, examples of exceptional modifications to this intricate organ are scarce. The unique eye of the four-eyed fish Anableps anableps is composed of duplicated corneas and pupils, as well as specialized retina regions associated with simultaneous aerial and aquatic vision. In a previous transcriptomic study of the A. anableps developing eye we identified expression of twenty non-visual and eleven visual opsin genes. Here, we surveyed the expression territories of three non-visual melanopsins genes (opn4×1, opn4×2, opn4m3), one teleost multiple tissue opsin (tmt1b) and two visual opsins (lws and rh2-1) in dorsal and ventral retinas. Our data showed that asymmetry of non-visual opsin expression is only established after birth. During embryonic development, while inside pregnant females, the expression of opn4×1, opn4×2, and tmt1b spans the whole retina. In juvenile fish (post birth), the expression of opn4×1, opn4×2, opn4m3, and tmt1b genes becomes restricted to the ventral retina, which receives aerial light. Raising juvenile fish in clear water instead of the murky waters found in its natural habitat is sufficient to change gene expression territories of opn4×1, opn4×2, opn4m3, tmt1b, and rh2-1, demonstrating that different lighting conditions can shift opsin expression and potentially contribute to changes in spectral sensitivity in the four eyed fish.
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Affiliation(s)
- Daniele Salgado
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Bertha R. Mariluz
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Maysa Araujo
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
| | - Jamily Lorena
- Department of Integrative Biology, Michigan State University, East Lansing, MI, United States
| | - Louise N. Perez
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
| | | | - Josane de F. Sousa
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
| | - Patricia N. Schneider
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, Brazil
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
- *Correspondence: Patricia N. Schneider,
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Lupše N, Cortesi F, Freese M, Marohn L, Pohlman JD, Wysujack K, Hanel R, Musilova Z. Visual gene expression reveals a cone to rod developmental progression in deep-sea fishes. Mol Biol Evol 2021; 38:5664-5677. [PMID: 34562090 PMCID: PMC8662630 DOI: 10.1093/molbev/msab281] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Vertebrates use cone cells in the retina for colour vision and rod cells to see in dim light. Many deep-sea fishes have adapted to their environment to have only rod cells in the retina, while both rod and cone genes are still preserved in their genomes. As deep-sea fish larvae start their lives in the shallow, and only later submerge to the depth, they have to cope with diverse environmental conditions during ontogeny. Using a comparative transcriptomic approach in 20 deep-sea fish species from eight teleost orders, we report on a developmental cone-to-rod switch. While adults mostly rely on rod opsin (RH1) for vision in dim light, larvae almost exclusively express middle-wavelength-sensitive ("green") cone opsins (RH2) in their retinas. The phototransduction cascade genes follow a similar ontogenetic pattern of cone- followed by rod-specific gene expression in most species, except for the pearleye and sabretooth (Aulopiformes), in which the cone cascade remains dominant throughout development. By inspecting the whole genomes of five deep-sea species (four of them sequenced within this study: Idiacanthus fasciola, Chauliodus sloani; Stomiiformes; Coccorella atlantica, and Scopelarchus michaelsarsi; Aulopiformes), we found that deep-sea fish possess one or two copies of the rod RH1 opsin gene, and up to seven copies of the cone RH2 opsin genes in their genomes, while other cone opsin classes have been mostly lost. Our findings hence provide molecular evidence for a limited opsin gene repertoire and a conserved vertebrate pattern whereby cone photoreceptors develop first and rod photoreceptors are added only at later developmental stages.
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Affiliation(s)
- Nik Lupše
- Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 12844 Prague, Czech Republic
| | - Fabio Cortesi
- Queensland Brain Institute, University of Queensland, Brisbane 4072 QLD, Australia
| | - Marko Freese
- Thünen Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany
| | - Lasse Marohn
- Thünen Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany
| | - Jan-Dag Pohlman
- Thünen Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany
| | - Klaus Wysujack
- Thünen Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany
| | - Reinhold Hanel
- Thünen Institute of Fisheries Ecology, Herwigstraße 31, 27572, Bremerhaven, Germany
| | - Zuzana Musilova
- Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 12844 Prague, Czech Republic
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Crawford MA, Schmidt WF, Broadhurst CL, Wang Y. Lipids in the origin of intracellular detail and speciation in the Cambrian epoch and the significance of the last double bond of docosahexaenoic acid in cell signaling. Prostaglandins Leukot Essent Fatty Acids 2021; 166:102230. [PMID: 33588307 DOI: 10.1016/j.plefa.2020.102230] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/06/2020] [Accepted: 12/15/2020] [Indexed: 11/24/2022]
Abstract
One of the great unanswered biological questions is the absolute necessity of the polyunsaturated lipid docosahexaenoic acid (DHA; 22:6n-3) in retinal and neural tissues. Everything from the simple eye spot of dinoflagellates to cephalopods to every class of vertebrates uses DHA, yet it is abundant only in cold water marine food chains. Docosapentaenoic acids (DPAs; 22:5n-6 and especially 22:5n-3) are fairly plentiful in food chains yet cannot substitute for DHA. About 600 million years ago, multi-cellular, air breathing systems evolved rapidly and 32 phyla came into existence in a short geological time span; the "Cambrian Explosion". Eukaryotic intracellular detail requires cell membranes, which are constructed of complex lipids, and proteins. Proteins and nucleic acids would have been abundant during the first 2.5-5 billion years of anaerobic life but lipids, especially unsaturated fatty acids, would not. We hypothesize lipid biology was a key driver of the Cambrian Explosion, because it alone provides for compartmentalization and specialization within cells DHA has six methylene interrupted double bonds providing controlled electron flow at precise energy levels; this is essential for visual acuity and truthful execution of the neural pathways which make up our recollections, information processing and consciousness. The last double bond is critical for the evolution and function of the photoreceptor and neuronal and synaptic signaling systems. It completes a quantum mechanical device for the regulation of current flow with absolute signal precision based on electron tunneling (ET). DHA's methylene interruption distance is < 6 Å, making ET transfer between the π-orbitals feasible throughout the molecule. The possibility fails if one double bond is removed and replaced by a saturated bond as in the DPAs. The molecular biophysical foundation of neural signaling can also include the discrete pattern of paired spin states that arise in the DHA double bond and methylene regions. The complexity depends upon the number of C13 and H1 molecular sites in which spin states are coupled. Electron wave harmonics with entanglement and cohesion provide a mechanism for learning and memory, and power cognition and complex human brain functions.
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Affiliation(s)
- Michael A Crawford
- The Department of Metabolism and Institute of Brain Cemistry and Human Nutrition, Digestion and Reproduction. Chelsea and Westminster Hospital Campus, Imperial College, London SW10 9NH, United Kingdom.
| | - Walter F Schmidt
- United States Department of Agriculture Agricultural Research Service, Beltsville, MD, USA
| | - C Leigh Broadhurst
- United States Department of Agriculture Agricultural Research Service, Beltsville, MD, USA
| | - Yiqun Wang
- The Department of Metabolism and Institute of Brain Cemistry and Human Nutrition, Digestion and Reproduction. Chelsea and Westminster Hospital Campus, Imperial College, London SW10 9NH, United Kingdom
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Fritsch R, Collin SP, Michiels NK. Anatomical Analysis of the Retinal Specializations to a Crypto-Benthic, Micro-Predatory Lifestyle in the Mediterranean Triplefin Blenny Tripterygion delaisi. Front Neuroanat 2017; 11:122. [PMID: 29311852 PMCID: PMC5732991 DOI: 10.3389/fnana.2017.00122] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 11/28/2017] [Indexed: 12/27/2022] Open
Abstract
The environment and lifestyle of a species are known to exert selective pressure on the visual system, often demonstrating a tight link between visual morphology and ecology. Many studies have predicted the visual requirements of a species by examining the anatomical features of the eye. However, among the vast number of studies on visual specializations in aquatic animals, only a few have focused on small benthic fishes that occupy a heterogeneous and spatially complex visual environment. This study investigates the general retinal anatomy including the topography of both the photoreceptor and ganglion cell populations and estimates the spatial resolving power (SRP) of the eye of the Mediterranean triplefin Tripterygion delaisi. Retinal wholemounts were prepared to systematically and quantitatively analyze photoreceptor and retinal ganglion cell (RGC) densities using design-based stereology. To further examine the retinal structure, we also used magnetic resonance imaging (MRI) and histological examination of retinal cross sections. Observations of the triplefin's eyes revealed them to be highly mobile, allowing them to view the surroundings without body movements. A rostral aphakic gap and the elliptical shape of the eye extend its visual field rostrally and allow for a rostro-caudal accommodatory axis, enabling this species to focus on prey at close range. Single and twin cones dominate the retina and are consistently arranged in one of two regular patterns, which may enhance motion detection and color vision. The retina features a prominent, dorso-temporal, convexiclivate fovea with an average density of 104,400 double and 30,800 single cones per mm2, and 81,000 RGCs per mm2. Based on photoreceptor spacing, SRP was calculated to be between 6.7 and 9.0 cycles per degree. Location and resolving power of the fovea would benefit the detection and identification of small prey in the lower frontal region of the visual field.
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Affiliation(s)
- Roland Fritsch
- Animal Evolutionary Ecology, Department of Biology, Institute of Evolution and Ecology, University of Tübingen, Tübingen, Germany
| | - Shaun P. Collin
- The Oceans Institute, The University of Western Australia, Crawley, WA, Australia
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Nico K. Michiels
- Animal Evolutionary Ecology, Department of Biology, Institute of Evolution and Ecology, University of Tübingen, Tübingen, Germany
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de Busserolles F, Cortesi F, Helvik JV, Davies WIL, Templin RM, Sullivan RKP, Michell CT, Mountford JK, Collin SP, Irigoien X, Kaartvedt S, Marshall J. Pushing the limits of photoreception in twilight conditions: The rod-like cone retina of the deep-sea pearlsides. SCIENCE ADVANCES 2017; 3:eaao4709. [PMID: 29134201 PMCID: PMC5677336 DOI: 10.1126/sciadv.aao4709] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/17/2017] [Indexed: 06/07/2023]
Abstract
Most vertebrates have a duplex retina comprising two photoreceptor types, rods for dim-light (scotopic) vision and cones for bright-light (photopic) and color vision. However, deep-sea fishes are only active in dim-light conditions; hence, most species have lost their cones in favor of a simplex retina composed exclusively of rods. Although the pearlsides, Maurolicus spp., have such a pure rod retina, their behavior is at odds with this simplex visual system. Contrary to other deep-sea fishes, pearlsides are mostly active during dusk and dawn close to the surface, where light levels are intermediate (twilight or mesopic) and require the use of both rod and cone photoreceptors. This study elucidates this paradox by demonstrating that the pearlside retina does not have rod photoreceptors only; instead, it is composed almost exclusively of transmuted cone photoreceptors. These transmuted cells combine the morphological characteristics of a rod photoreceptor with a cone opsin and a cone phototransduction cascade to form a unique photoreceptor type, a rod-like cone, specifically tuned to the light conditions of the pearlsides' habitat (blue-shifted light at mesopic intensities). Combining properties of both rods and cones into a single cell type, instead of using two photoreceptor types that do not function at their full potential under mesopic conditions, is likely to be the most efficient and economical solution to optimize visual performance. These results challenge the standing paradigm of the function and evolution of the vertebrate duplex retina and emphasize the need for a more comprehensive evaluation of visual systems in general.
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Affiliation(s)
- Fanny de Busserolles
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - Fabio Cortesi
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jon Vidar Helvik
- Department of Biology, University of Bergen, Bergen 5020, Norway
| | - Wayne I. L. Davies
- The Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
- School of Biological Science, The University of Western Australia, Crawley, Western Australia 6009, Australia
- Lions Eye Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Rachel M. Templin
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Robert K. P. Sullivan
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Craig T. Michell
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistokatu 7, FI-80101 Joensuu, Finland
| | - Jessica K. Mountford
- The Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
- School of Biological Science, The University of Western Australia, Crawley, Western Australia 6009, Australia
- Lions Eye Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Shaun P. Collin
- The Oceans Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
- School of Biological Science, The University of Western Australia, Crawley, Western Australia 6009, Australia
- Lions Eye Institute, The University of Western Australia, Crawley, Western Australia 6009, Australia
| | - Xabier Irigoien
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
- Marine Research, AZTI - Tecnalia, Herrera Kaia, Portualdea z/g, 20110 Pasaia (Gipuzkoa), Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Stein Kaartvedt
- Red Sea Research Center, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
- Department of Biosciences, University of Oslo, Oslo 0316, Norway
| | - Justin Marshall
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
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