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Battelle BA. Opsins and Their Expression Patterns in the Xiphosuran Limulus polyphemus. THE BIOLOGICAL BULLETIN 2017; 233:3-20. [PMID: 29182506 DOI: 10.1086/693730] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The American horseshoe crab Limulus polyphemus (Linnaeus, 1758) is one of four extant species of xiphosuran chelicerates, the sister group to arachnids. Because of their position in the arthropod family tree and because they exhibit many plesiomorphic characteristics, Xiphosura are considered a proxy for the euchelicerate ancestor and therefore important for understanding the evolution and diversification of chelicerates and arthropods. Limulus polyphemus is the most extensively studied xiphosuran, and its visual system has long been a focus of studies critical for our understanding of basic mechanisms of vision and the evolution of visual systems in arthropods. Building upon a wealth of information about the anatomy and physiology of its visual system, advances in genetic approaches have greatly expanded possibilities for understanding its biochemistry. This review focuses on studies of opsin expression in L. polyphemus, which have been significantly advanced by the availability of transcriptomes and a recent high-quality assembly of its genome. These studies show that the repertoire of expressed opsins in L. polyphemus is far larger than anticipated, that the regulation of their expression in rhabdoms is far more complex than anticipated, and that photosensitivity may be distributed widely throughout the L. polyphemus central nervous system. The visual system of L. polyphemus is now arguably the best understood among chelicerates, and as such, it is a critical resource for furthering our understanding of the evolution and diversification of visual systems in arthropods.
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Key Words
- CNS, central nervous system
- LE, lateral eye
- LWS, long wavelength-sensitive
- LpArthOps, Limulus arthropsin
- LpCOps, Limulus C-type opsin
- LpOps, Limulus opsin
- LpPerOps, Limulus peropsin
- ME, median eye
- MWS, medium wavelength-sensitive
- Rh-LpOps, Limulus opsin in rhabdoms
- SWS, short wavelength-sensitive
- VE, ventral eye
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Schröer WD. Fine structure of the anterior median eyes of the funnel-web spider Agelena labyrinthica (Araneae: Agelenidae). ARTHROPOD STRUCTURE & DEVELOPMENT 2017; 46:196-214. [PMID: 28108399 DOI: 10.1016/j.asd.2017.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/08/2017] [Accepted: 01/10/2017] [Indexed: 06/06/2023]
Abstract
Only few electron microscopic studies exist on the structure of the main eyes (anterior median eyes, AME) of web spiders. The present paper provides details on the anatomy of the AME in the funnel-web spider Agelena labyrinthica. The retina consists of two separate regions with differently arranged photoreceptor cells. Its central part has sensory cells with rhabdomeres on 2, 3, or 4 sides, whereas those of the ventral retina have only two rhabdomeres on opposite sides. In addition, the rhabdomeres of the ventral retina are arranged in a specific way: Whereas in the most ventral part they form long tangential rows, those towards the center are detached and are arranged radially. All sensory cells are wrapped by unpigmented pigment cell processes. In agelenid spiders the axons of the sensory cells exit from the middle of the cell body; their fine structure and course through the eye cup is described in detail. In the central part of the retina efferent nerve fibres were found forming synapses along the distal region of the receptor cells. A muscle is attached laterally to each eye cup that allows mainly rotational movements of the eyes. The optical performance (image resolution) of these main eyes with relatively few visual cells is discussed.
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Battelle BA, Ryan JF, Kempler KE, Saraf SR, Marten CE, Warren WC, Minx PJ, Montague MJ, Green PJ, Schmidt SA, Fulton L, Patel NH, Protas ME, Wilson RK, Porter ML. Opsin Repertoire and Expression Patterns in Horseshoe Crabs: Evidence from the Genome of Limulus polyphemus (Arthropoda: Chelicerata). Genome Biol Evol 2016; 8:1571-89. [PMID: 27189985 PMCID: PMC4898813 DOI: 10.1093/gbe/evw100] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/24/2016] [Indexed: 12/19/2022] Open
Abstract
Horseshoe crabs are xiphosuran chelicerates, the sister group to arachnids. As such, they are important for understanding the most recent common ancestor of Euchelicerata and the evolution and diversification of Arthropoda. Limulus polyphemus is the most investigated of the four extant species of horseshoe crabs, and the structure and function of its visual system have long been a major focus of studies critical for understanding the evolution of visual systems in arthropods. Likewise, studies of genes encoding Limulus opsins, the protein component of the visual pigments, are critical for understanding opsin evolution and diversification among chelicerates, where knowledge of opsins is limited, and more broadly among arthropods. In the present study, we sequenced and assembled a high quality nuclear genomic sequence of L. polyphemus and used these data to annotate the full repertoire of Limulus opsins. We conducted a detailed phylogenetic analysis of Limulus opsins, including using gene structure and synteny information to identify relationships among different opsin classes. We used our phylogeny to identify significant genomic events that shaped opsin evolution and therefore the visual system of Limulus We also describe the tissue expression patterns of the 18 opsins identified and show that transcripts encoding a number, including a peropsin, are present throughout the central nervous system. In addition to significantly extending our understanding of photosensitivity in Limulus and providing critical insight into the genomic evolution of horseshoe crab opsins, this work provides a valuable genomic resource for addressing myriad questions related to xiphosuran physiology and arthropod evolution.
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Affiliation(s)
- Barbara-Anne Battelle
- Whitney Laboratory for Marine Bioscience, Departments of Neuroscience and Biology, University of Florida
| | - Joseph F Ryan
- Whitney Laboratory for Marine Bioscience, Department of Biology, University of Florida
| | - Karen E Kempler
- Whitney Laboratory for Marine Bioscience, Departments of Neuroscience and Biology, University of Florida
| | - Spencer R Saraf
- Whitney Laboratory for Marine Bioscience, Departments of Neuroscience and Biology, University of Florida Present address: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY
| | - Catherine E Marten
- Whitney Laboratory for Marine Bioscience, Departments of Neuroscience and Biology, University of Florida Present address: Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, FL
| | - Wesley C Warren
- McDonnell Genome Institute, Washington University School of Medicine in St. Louis
| | - Patrick J Minx
- McDonnell Genome Institute, Washington University School of Medicine in St. Louis
| | - Michael J Montague
- McDonnell Genome Institute, Washington University School of Medicine in St. Louis
| | - Pamela J Green
- Department of Plant and Soil Sciences, School of Marine Science and Policy, Delaware Biotechnology Institute, University of Delaware
| | - Skye A Schmidt
- Department of Plant and Soil Sciences, School of Marine Science and Policy, Delaware Biotechnology Institute, University of Delaware
| | - Lucinda Fulton
- McDonnell Genome Institute, Washington University School of Medicine in St. Louis
| | - Nipam H Patel
- Department of Molecular Cell Biology, Center for Integrative Genomics, University of California, Berkley
| | - Meredith E Protas
- Department of Molecular Cell Biology, Center for Integrative Genomics, University of California, Berkley Present address: Department of Natural Sciences and Mathematics, Dominican University of California, San Rafael, CA
| | - Richard K Wilson
- McDonnell Genome Institute, Washington University School of Medicine in St. Louis
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Battelle BA. What the clock tells the eye: lessons from an ancient arthropod. Integr Comp Biol 2013; 53:144-53. [PMID: 23639718 DOI: 10.1093/icb/ict020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Circadian changes in visual sensitivity have been observed in a wide range of species, vertebrates, and invertebrates, but the processes impacted and the underlying mechanisms largely are unexplored. Among arthropods, effects of circadian signals on vision have been examined in most detail in the lateral compound eye (LE) of the American horseshoe crab, Limulus polyphemus, a chelicerate arthropod. As a consequence of processes influenced by a central circadian clock, Limulus can see at night nearly as well as they do during the day. The effects of the clock on horseshoe crab LE retinas are diverse and include changes in structure, gene expression, and rhabdom biochemistry. An examination of the known effects of circadian rhythms on LEs shows that the effects have three important outcomes: an increase in visual sensitivity at night, a rapid decrease in visual sensitivity at dawn, and maintenance of eyes in a relatively low state of sensitivity during the day, even in the dark. All three outcomes may be critically important for species' survival. Specific effects of circadian rhythms on vision will certainly vary with species and according to life styles. Studies of the circadian regulation of Limulus vision have revealed that these effects can be extremely diverse and profound and suggest that circadian clocks can play a critical role in the ability of animals to adapt to the dramatic daily changes in ambient illumination.
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Affiliation(s)
- B-A Battelle
- Whitney Laboratory for Marine Bioscience and Departments of Neuroscience and Biology, University of Florida, St Augustine, FL 32080, USA.
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Battelle BA, Kempler KE, Parker AK, Gaddie CD. Opsin1-2, G(q)α and arrestin levels at Limulus rhabdoms are controlled by diurnal light and a circadian clock. ACTA ACUST UNITED AC 2013; 216:1837-49. [PMID: 23393287 DOI: 10.1242/jeb.083519] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Dark and light adaptation in photoreceptors involve multiple processes including those that change protein concentrations at photosensitive membranes. Light- and dark-adaptive changes in protein levels at rhabdoms have been described in detail in white-eyed Drosophila maintained under artificial light. Here we tested whether protein levels at rhabdoms change significantly in the highly pigmented lateral eyes of wild-caught Limulus polyphemus maintained in natural diurnal illumination and whether these changes are under circadian control. We found that rhabdomeral levels of opsins (Ops1-2), the G protein activated by rhodopsin (G(q)α) and arrestin change significantly from day to night and that nighttime levels of each protein at rhabdoms are significantly influenced by signals from the animal's central circadian clock. Clock input at night increases Ops1-2 and G(q)α and decreases arrestin levels at rhabdoms. Clock input is also required for a rapid decrease in rhabdomeral Ops1-2 beginning at sunrise. We found further that dark adaptation during the day and the night are not equivalent. During daytime dark adaptation, when clock input is silent, the increase of Ops1-2 at rhabdoms is small and G(q)α levels do not increase. However, increases in Ops1-2 and G(q)α at rhabdoms are enhanced during daytime dark adaptation by treatments that elevate cAMP in photoreceptors, suggesting that the clock influences dark-adaptive increases in Ops1-2 and G(q)α at Limulus rhabdoms by activating cAMP-dependent processes. The circadian regulation of Ops1-2 and G(q)α levels at rhabdoms probably has a dual role: to increase retinal sensitivity at night and to protect photoreceptors from light damage during the day.
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Affiliation(s)
- Barbara-Anne Battelle
- The Whitney Laboratory for Marine Bioscience, 9505 Ocean Shore Blvd, St Augustine, FL 32080-8610, USA.
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Battelle BA. The eyes of Limulus polyphemus (Xiphosura, Chelicerata) and their afferent and efferent projections. ARTHROPOD STRUCTURE & DEVELOPMENT 2006; 35:261-74. [PMID: 18089075 DOI: 10.1016/j.asd.2006.07.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Accepted: 06/22/2006] [Indexed: 05/16/2023]
Abstract
The visual system of the American horseshoe crab Limulus polyphemus (L. polyphemus) is an important preparation for studying the photoresponse, the circadian modulation of the photoresponse and visual information processing. Given its unique position in phylogeny the structure of its visual system also informs studies of the relationships among arthropods and the characteristics of eurarthropods. Much has been learned about the organization of the relatively simple L. polyphemus visual system, but much remains to be discovered. This review summarizes current knowledge of the structure of L. polyphemus eyes and the organization of their afferent and efferent projections and points to important unanswered questions.
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Affiliation(s)
- B-A Battelle
- Whitney Laboratory and Department of Neuroscience, University of Florida, 9505 Ocean Shore Blvd., St. Augustine, FL 32080, USA
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Kovoor J, Muñoz-cuevas A, Ortega-Escobar J. Neurosecretory cells in the optic lobes of the brain and activity rhythms inLycosa tarentula(Araneae: Lycosidae). BIOL RHYTHM RES 2005. [DOI: 10.1080/09291010500051659] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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