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Pang JJ, Jiang X, Wu SM. Linear and Nonlinear Behaviors of the Photoreceptor Coupled Network. J Neurosci 2024; 44:e1433232024. [PMID: 38423760 PMCID: PMC11026348 DOI: 10.1523/jneurosci.1433-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 02/20/2024] [Accepted: 02/20/2024] [Indexed: 03/02/2024] Open
Abstract
Photoreceptors are electrically coupled to one another, and the spatiotemporal properties of electrical synapses in a two-dimensional retinal network are still not well studied, because of the limitation of the single electrode or pair recording techniques which do not allow simultaneously measuring responses of multiple photoreceptors at various locations in the retina. A multiple electrode recording system is needed. In this study, we investigate the network properties of the two-dimensional rod coupled array of the salamander retina (both sexes were used) by using the newly available multiple patch electrode system that allows simultaneous recordings from up to eight cells and to determine the electrical connectivity among multiple rods. We found direct evidence that voltage signal spread in the rod-rod coupling network in the absence of I h (mediated by HCN channels) is passive and follows the linear cable equation. Under physiological conditions, I h shapes the network signal by progressively shortening the response time-to-peak of distant rods, compensating the time loss of signal traveling from distant rods to bipolar cell somas and facilitating synchronization of rod output signals. Under voltage-clamp conditions, current flow within the coupled rods follows Ohm's law, supporting the idea that nonlinear behaviors of the rod network are dependent on membrane voltage. Rod-rod coupling is largely symmetrical in the 2D array, and voltage-clamp blocking the next neighboring rod largely suppresses rod signal spread into the second neighboring rod, suggesting that indirect coupling pathways play a minor role in rod-rod coupling.
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Affiliation(s)
- Ji-Jie Pang
- Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Xiaolong Jiang
- Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Samuel M Wu
- Departments of Ophthalmology and Neuroscience, Baylor College of Medicine, Houston, Texas 77030
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2
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Liu CY, Zhang XM, Yue HF, Shi YX. [The role of Müller cells in the formation and development of macular hole]. Zhonghua Yan Ke Za Zhi 2023; 59:948-953. [PMID: 37641407 DOI: 10.3760/cma.j.cn112142-20230627-00246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Müller cells are important glial cells in the retina, which play important roles in maintaining the stability of the retina by mechanical support, homeostasis, and physiological metabolism, as well as protecting photoreceptor cells and retinal pigment epithelial cells. The degeneration and destruction of Müller cells are often accompanied by various retinal diseases, and the function of Müller cells is changed under pathological conditions. Based on the summary of the morphology, distribution and function of Müller cells, this article analyzes the different manifestations and changes of Müller cells in different stages of macular hole and the closely related mechanisms, aiming to clarify the role of Müller cells in the formation and development of macular hole and to provide reference for the prediction of disease progression and guidance of treatment.(This article was published ahead of print on the official website of Chinese Journal of Ophthalmology on Augest 28, 2023).
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Affiliation(s)
- C Y Liu
- The First Clinical Medical College of Shanxi Medical University, Taiyuan 030001, China
| | - X M Zhang
- Shanxi Eye Hospital Affiliated to Shanxi Medical University, Taiyuan 030002, China
| | - H F Yue
- Shanxi Eye Hospital Affiliated to Shanxi Medical University, Taiyuan 030002, China
| | - Y X Shi
- The First Clinical Medical College of Shanxi Medical University, Taiyuan 030001, China
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3
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Abstract
Light provides a widely abundant energy source and valuable sensory cue in nature. Most animals exposed to light have photoreceptor cells and in addition to eyes, there are many extraocular strategies for light sensing. Here, we review how these simpler forms of detecting light can mediate rapid behavioural responses in animals. Examples of these behaviours include photophobic (light avoidance) or scotophobic (shadow) responses, photokinesis, phototaxis and wavelength discrimination. We review the cells and response mechanisms in these forms of elementary light detection, focusing on aquatic invertebrates with some protist and terrestrial examples to illustrate the general principles. Light cues can be used very efficiently by these simple photosensitive systems to effectively guide animal behaviours without investment in complex and energetically expensive visual structures.
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Affiliation(s)
- Emelie Brodrick
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
- Centre for Organismal Studies, University of Heidelberg, 69120, Heidelberg, Germany
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4
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Wahle MA, Kim HQ, Menke DB, Lauderdale JD, Rasys AM. Maturation and refinement of the maculae and foveae in the Anolis sagrei lizard. Exp Eye Res 2023; 234:109611. [PMID: 37536437 DOI: 10.1016/j.exer.2023.109611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 06/30/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023]
Abstract
The fovea is a pit in the center of the macula, which is a region of the retina with a high concentration of photoreceptor cells, which accounts for a large degree of visual acuity in primates. The maturation of this primate visual acuity area is characterized by the shallowing and widening of the foveal pit, a decrease in the diameter of the rod-free zone, and an increase in photoreceptor cells packing after birth. Maturation occurs concurrently with progressing age, increasing eye size, and retinal length/area. These observations have led to the hypothesis that the maturation of the fovea might be a function of mechanical variables that remodel the retina. However, this has never been explored outside of primates. Here, we take advantage of the Anolis sagrei lizard, which has a bifoveated retina, to study maturation of the fovea and macula. Eyes were collected from male and female lizards-hatchling, 2-month, 4-month, 6-month, and adult. We found that Anolis maculae undergo a maturation process somewhat different than what has been observed in primates. Anole macular diameters actually increase in size and undergo minimal photoreceptor cell packing, possessing a near complete complement of these cells at the time of hatching. As the anole eye expands, foveal centers experience little change in overall retina cell density with most cell redistribution occurring at macular borders and peripheral retina areas. Gene editing technology has recently been developed in lizards; this study provides a baseline of normal retina maturation for future genetic manipulation studies in anoles.
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Affiliation(s)
- M Austin Wahle
- Department of Genetics, The University of Georgia, Athens, GA, 30602, USA
| | - Hannah Q Kim
- Department of Cellular Biology, The University of Georgia, Athens, GA, 30602, USA
| | - Douglas B Menke
- Department of Genetics, The University of Georgia, Athens, GA, 30602, USA
| | - James D Lauderdale
- Department of Cellular Biology, The University of Georgia, Athens, GA, 30602, USA; Neuroscience Division of the Biomedical and Translational Sciences Institute, The University of Georgia, Athens, GA, 30602, USA
| | - Ashley M Rasys
- Department of Cellular Biology, The University of Georgia, Athens, GA, 30602, USA.
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5
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Chung J, Newman-Smith E, Kourakis MJ, Miao Y, Borba C, Medina J, Laurent T, Gallean B, Faure E, Smith WC. A single oscillating proto-hypothalamic neuron gates taxis behavior in the primitive chordate Ciona. Curr Biol 2023; 33:3360-3370.e4. [PMID: 37490920 PMCID: PMC10528541 DOI: 10.1016/j.cub.2023.06.080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/05/2023] [Accepted: 06/29/2023] [Indexed: 07/27/2023]
Abstract
Ciona larvae display a number of behaviors, including negative phototaxis. In negative phototaxis, the larvae first perform short spontaneous rhythmic casting swims. As larvae are cast in a light field, their photoreceptors are directionally shaded by an associated pigment cell, providing a phototactic cue. This then evokes an extended negative taxis swim. We report here that the larval forebrain of Ciona has a previously uncharacterized single slow-oscillating inhibitory neuron (neuron cor-assBVIN78) that projects to the midbrain, where it targets key interneurons of the phototaxis circuit known as the photoreceptor relay neurons. The anatomical location, gene expression, and oscillation of cor-assBVIN78 suggest homology to oscillating neurons of the vertebrate hypothalamus. Ablation of cor-assBVIN78 results in larvae showing extended phototaxis-like swims, even in the absence of phototactic cues. These results indicate that cor-assBVIN78 has a gating activity on phototaxis by projecting temporally oscillating inhibition to the photoreceptor relay neurons. However, in intact larvae, the frequency of cor-assBVIN78 oscillation does not match that of the rhythmic spontaneous swims, indicating that the troughs in oscillations do not themselves initiate swims but rather that cor-assBVIN78 may modulate the phototaxis circuit by filtering out low-level inputs while restricting them temporally to the troughs in inhibition.
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Affiliation(s)
- Janeva Chung
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Erin Newman-Smith
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Matthew J Kourakis
- Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Yishen Miao
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Cezar Borba
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Juan Medina
- College of Creative Studies, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Tao Laurent
- Laboratoire d'Informatique, de Robotique et de Microélectronique de Montpellier, Université de Montpellier, CNRS, Montpellier, France
| | - Benjamin Gallean
- Centre de Recherche de Biologie cellulaire de Montpellier, Université de Montpellier, CNRS, Montpellier, France
| | - Emmanuel Faure
- Laboratoire d'Informatique, de Robotique et de Microélectronique de Montpellier, Université de Montpellier, CNRS, Montpellier, France
| | - William C Smith
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA; Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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Rocha-Martins M, Nerli E, Kretzschmar J, Weigert M, Icha J, Myers EW, Norden C. Neuronal migration prevents spatial competition in retinal morphogenesis. Nature 2023; 620:615-624. [PMID: 37558872 DOI: 10.1038/s41586-023-06392-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 06/30/2023] [Indexed: 08/11/2023]
Abstract
The concomitant occurrence of tissue growth and organization is a hallmark of organismal development1-3. This often means that proliferating and differentiating cells are found at the same time in a continuously changing tissue environment. How cells adapt to architectural changes to prevent spatial interference remains unclear. Here, to understand how cell movements that are key for growth and organization are orchestrated, we study the emergence of photoreceptor neurons that occur during the peak of retinal growth, using zebrafish, human tissue and human organoids. Quantitative imaging reveals that successful retinal morphogenesis depends on the active bidirectional translocation of photoreceptors, leading to a transient transfer of the entire cell population away from the apical proliferative zone. This pattern of migration is driven by cytoskeletal machineries that differ depending on the direction: microtubules are exclusively required for basal translocation, whereas actomyosin is involved in apical movement. Blocking the basal translocation of photoreceptors induces apical congestion, which hampers the apical divisions of progenitor cells and leads to secondary defects in lamination. Thus, photoreceptor migration is crucial to prevent competition for space, and to allow concurrent tissue growth and lamination. This shows that neuronal migration, in addition to its canonical role in cell positioning4, can be involved in coordinating morphogenesis.
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Affiliation(s)
- Mauricio Rocha-Martins
- Instituto Gulbenkian de Ciência, Oeiras, Portugal.
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
- Center for Systems Biology Dresden (CSBD), Dresden, Germany.
| | - Elisa Nerli
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Systems Biology Dresden (CSBD), Dresden, Germany
| | - Jenny Kretzschmar
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Martin Weigert
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Systems Biology Dresden (CSBD), Dresden, Germany
- Institute of Bioengineering, School of Life Sciences École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Jaroslav Icha
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Eugene W Myers
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Systems Biology Dresden (CSBD), Dresden, Germany
| | - Caren Norden
- Instituto Gulbenkian de Ciência, Oeiras, Portugal.
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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Gu Q, Tian Y, Han J. Protocol for electron microscopy of Drosophila photoreceptor cells. STAR Protoc 2022; 3:101496. [PMID: 35776650 PMCID: PMC9243293 DOI: 10.1016/j.xpro.2022.101496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/08/2022] [Accepted: 06/06/2022] [Indexed: 11/23/2022] Open
Abstract
In Drosophila, mutations in genes that prevent normal Ca2+ influx after light stimulation usually cause light-dependent retinal degeneration or neurodegeneration, detectable by defects in eye morphology. Here, we present a protocol based on electron microscopy (EM) to observe the morphological structure of photoreceptor cells in Drosophila. We detail how to fix, dehydrate, embed, and polymerize compound eye samples, followed by sectioning, post-staining, and image acquisition, to assess the eye morphology at the ultrastructural level. For complete details on the use and execution of this protocol, please refer to Gu et al. (2020). A protocol for revealing the ultrastructure of Drosophila photoreceptor cells Preparing compound eye samples for electron microscope observation Dissecting molecular mechanisms underlying retinal degeneration
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
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Affiliation(s)
- Qiuxiang Gu
- School of Life Science, Nantong University, Nantong, Jiangsu 226001, China
| | - Yao Tian
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China.
| | - Junhai Han
- School of Life Science and Technology, the Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China.
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Yu Z, Streng C, Seibeld RF, Igbalajobi OA, Leister K, Ingelfinger J, Fischer R. Genome-wide analyses of light-regulated genes in Aspergillus nidulans reveal a complex interplay between different photoreceptors and novel photoreceptor functions. PLoS Genet 2021; 17:e1009845. [PMID: 34679095 PMCID: PMC8535378 DOI: 10.1371/journal.pgen.1009845] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 09/28/2021] [Indexed: 12/04/2022] Open
Abstract
Fungi sense light of different wavelengths using blue-, green-, and red-light photoreceptors. Blue light sensing requires the “white-collar” proteins with flavin as chromophore, and red light is sensed through phytochrome. Here we analyzed genome-wide gene expression changes caused by short-term, low-light intensity illumination with blue-, red- or far-red light in Aspergillus nidulans and found that more than 1100 genes were differentially regulated. The largest number of up- and downregulated genes depended on the phytochrome FphA and the attached HOG pathway. FphA and the white-collar orthologue LreA fulfill activating but also repressing functions under all light conditions and both appear to have roles in the dark. Additionally, we found about 100 genes, which are red-light induced in the absence of phytochrome, suggesting alternative red-light sensing systems. We also found blue-light induced genes in the absence of the blue-light receptor LreA. We present evidence that cryptochrome may be part of this regulatory cue, but that phytochrome is essential for the response. In addition to in vivo data showing that FphA is involved in blue-light sensing, we performed spectroscopy of purified phytochrome and show that it responds indeed to blue light. Fungi are microorganisms with important roles in the environment, as symbionts, as pathogens, or as workhorses in biotechnology. They constantly need to adapt to changing environmental conditions, often far away from their optima. One important environmental factor, fungi respond to is ambient light. The presence of light tells them if they are exposed to a surface and thus potentially to heat, harmful irradiation, or desiccation or other stressful conditions, or whether they are growing inside soil or litter with more constant conditions. Interestingly, many fungi harbor photosensors for blue-, green- and red light. We show here that in the model fungus Aspergillus nidulans a large proportion of the genome is under light control, and many genes are regulated through phytochrome and thus by red light. However, phytochrome is also used for blue-light sensing. Many genes are controlled by blue- and by red light signaling systems, but many also respond only to specific wavelengths. The study provides important groundwork for future research to unravel how different genes are regulated at the molecular level and to decipher the biological meaning for the complex light-regulatory systems found in fungi.
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Affiliation(s)
- Zhenzhong Yu
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany
- Nanjing Agricultural University, Key Laboratory of Plant Immunity, Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing, China
- * E-mail: (ZY); (RF)
| | - Christian Streng
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany
| | - Ramon F. Seibeld
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany
| | - Olumuyiwa A. Igbalajobi
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany
| | - Kai Leister
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany
| | - Julian Ingelfinger
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany
| | - Reinhard Fischer
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Department of Microbiology, Karlsruhe, Germany
- * E-mail: (ZY); (RF)
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Affiliation(s)
- Daniele Dell'Orco
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, Strada le Grazie 8, I-37124, Verona, Italy
| | - Karl-Wilhelm Koch
- Department of Neuroscience, Division of Biochemistry, University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, D-26111, Oldenburg, Germany
| | - Giorgio Rispoli
- Department of Neuroscience and Rehabilitation, Section of Physiology, Via Borsari 46, I-44121, Ferrara, Italy.
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Łabuz G, Rayamajhi A, Khoramnia R, Palczewska G, Palczewski K, Holschbach A, Auffarth GU. THE LOSS OF INFRARED LIGHT SENSITIVITY OF PHOTORECEPTOR CELLS MEASURED WITH TWO-PHOTON EXCITATION AS AN INDICATOR OF DIABETIC RETINOPATHY: A Pilot Study. Retina 2021; 41:1302-1308. [PMID: 33323904 PMCID: PMC8137510 DOI: 10.1097/iae.0000000000003032] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Human photoreceptors are sensitive to infrared light (IR). This sensitivity can be used as a novel indicator of retinal function. Diabetic retinopathy patients were assessed using in vivo two-photon excitation and compared their scotopic IR threshold with that of healthy patients. METHODS Sixty-two participants, 28 healthy and 34 with diabetic retinopathy, underwent a comprehensive eye examination, where visual acuity and contrast sensitivity were assessed. Infrared thresholds were measured in the fovea and parafovea following 30-minute dark adaptation. A two-photon excitation device was used with integrated pulsed laser light (1,045 nm) for sensitivity testing and scanning laser ophthalmoscopy for fundus imaging. RESULTS The mean Snellen visual acuity of diabetic patients (6/7.7) was worse than that of the healthy patients (6/5.5), which was significantly different (P < 0.001). Disease patients had decreased contrast sensitivity, especially at 6 and 18 cycles/degree. The mean retinal sensitivity to IR light in eyes with diabetic retinopathy (11.6 ± 2.0 dB) was significantly (P < 0.001) lower than that in normal eyes (15.5 ± 1.3 dB). CONCLUSION Compared with healthy control subjects, the IR light sensitivity of diabetic patients was significantly impaired. Two-photon measurements can be used in the assessment of retinal disease, but further studies are needed to validate IR light stimulation in various stages of diabetic retinopathy.
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Affiliation(s)
- Grzegorz Łabuz
- Department of Ophthalmology, The David J Apple Center for Vision Research, University Hospital Heidelberg, Heidelberg, Germany;
| | - Asu Rayamajhi
- Department of Ophthalmology, The David J Apple Center for Vision Research, University Hospital Heidelberg, Heidelberg, Germany;
| | - Ramin Khoramnia
- Department of Ophthalmology, The David J Apple Center for Vision Research, University Hospital Heidelberg, Heidelberg, Germany;
| | - Grażyna Palczewska
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA
- Department of Medical Devices, Polgenix, Inc., Irvine, CA; and
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, CA
- Department of Medical Devices, Polgenix, Inc., Irvine, CA; and
| | | | - Gerd U. Auffarth
- Department of Ophthalmology, The David J Apple Center for Vision Research, University Hospital Heidelberg, Heidelberg, Germany;
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Pang JJ, Gao F, Wu SM. Generators of Pressure-Evoked Currents in Vertebrate Outer Retinal Neurons. Cells 2021; 10:cells10061288. [PMID: 34067375 PMCID: PMC8224636 DOI: 10.3390/cells10061288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/13/2021] [Accepted: 05/19/2021] [Indexed: 12/19/2022] Open
Abstract
(1) Background: High-tension glaucoma damages the peripheral vision dominated by rods. How mechanosensitive channels (MSCs) in the outer retina mediate pressure responses is unclear. (2) Methods: Immunocytochemistry, patch clamp, and channel fluorescence were used to study MSCs in salamander photoreceptors. (3) Results: Immunoreactivity of transient receptor potential channel vanilloid 4 (TRPV4) was revealed in the outer plexiform layer, K+ channel TRAAK in the photoreceptor outer segment (OS), and TRPV2 in some rod OS disks. Pressure on the rod inner segment evoked sustained currents of three components: (A) the inward current at <-50 mV (Ipi), sensitive to Co2+; (B) leak outward current at ≥-80 mV (Ipo), sensitive to intracellular Cs+ and ruthenium red; and (C) cation current reversed at ~10 mV (Ipc). Hypotonicity induced slow currents like Ipc. Environmental pressure and light increased the FM 1-43-identified open MSCs in the OS membrane, while pressure on the OS with internal Cs+ closed a Ca2+-dependent current reversed at ~0 mV. Rod photocurrents were thermosensitive and affected by MSC blockers. (4) Conclusions: Rods possess depolarizing (TRPV) and hyperpolarizing (K+) MSCs, which mediate mutually compensating currents between -50 mV and 10 mV, serve as an electrical cushion to minimize the impact of ocular mechanical stress.
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Broser M, Spreen A, Konold PE, Schiewer E, Adam S, Borin V, Schapiro I, Seifert R, Kennis JTM, Bernal Sierra YA, Hegemann P. NeoR, a near-infrared absorbing rhodopsin. Nat Commun 2020; 11:5682. [PMID: 33173168 PMCID: PMC7655827 DOI: 10.1038/s41467-020-19375-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 10/06/2020] [Indexed: 12/18/2022] Open
Abstract
The Rhizoclosmatium globosum genome encodes three rhodopsin-guanylyl cyclases (RGCs), which are predicted to facilitate visual orientation of the fungal zoospores. Here, we show that RGC1 and RGC2 function as light-activated cyclases only upon heterodimerization with RGC3 (NeoR). RGC1/2 utilize conventional green or blue-light-sensitive rhodopsins (λmax = 550 and 480 nm, respectively), with short-lived signaling states, responsible for light-activation of the enzyme. The bistable NeoR is photoswitchable between a near-infrared-sensitive (NIR, λmax = 690 nm) highly fluorescent state (QF = 0.2) and a UV-sensitive non-fluorescent state, thereby modulating the activity by NIR pre-illumination. No other rhodopsin has been reported so far to be functional as a heterooligomer, or as having such a long wavelength absorption or high fluorescence yield. Site-specific mutagenesis and hybrid quantum mechanics/molecular mechanics simulations support the idea that the unusual photochemical properties result from the rigidity of the retinal chromophore and a unique counterion triad composed of two glutamic and one aspartic acids. These findings substantially expand our understanding of the natural potential and limitations of spectral tuning in rhodopsin photoreceptors.
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Affiliation(s)
- Matthias Broser
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany.
| | - Anika Spreen
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Patrick E Konold
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Enrico Schiewer
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Suliman Adam
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Veniamin Borin
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Igor Schapiro
- Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Reinhard Seifert
- Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175, Bonn, Germany
| | - John T M Kennis
- Department of Physics and Astronomy, Faculty of Science, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | | | - Peter Hegemann
- Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
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Lu X, Shen Y, Campbell RE. Engineering Photosensory Modules of Non-Opsin-Based Optogenetic Actuators. Int J Mol Sci 2020; 21:E6522. [PMID: 32906617 PMCID: PMC7555876 DOI: 10.3390/ijms21186522] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 11/17/2022] Open
Abstract
Optogenetic (photo-responsive) actuators engineered from photoreceptors are widely used in various applications to study cell biology and tissue physiology. In the toolkit of optogenetic actuators, the key building blocks are genetically encodable light-sensitive proteins. Currently, most optogenetic photosensory modules are engineered from naturally-occurring photoreceptor proteins from bacteria, fungi, and plants. There is a growing demand for novel photosensory domains with improved optical properties and light-induced responses to satisfy the needs of a wider variety of studies in biological sciences. In this review, we focus on progress towards engineering of non-opsin-based photosensory domains, and their representative applications in cell biology and physiology. We summarize current knowledge of engineering of light-sensitive proteins including light-oxygen-voltage-sensing domain (LOV), cryptochrome (CRY2), phytochrome (PhyB and BphP), and fluorescent protein (FP)-based photosensitive domains (Dronpa and PhoCl).
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Affiliation(s)
- Xiaocen Lu
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; (X.L.); (Y.S.)
| | - Yi Shen
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; (X.L.); (Y.S.)
| | - Robert E. Campbell
- Department of Chemistry, University of Alberta, Edmonton, AB T6G 2G2, Canada; (X.L.); (Y.S.)
- Department of Chemistry, The University of Tokyo, Tokyo 113-0033, Japan
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Liu Y, Cao S, Yu M, Hu H. TMEM216 Deletion Causes Mislocalization of Cone Opsin and Rhodopsin and Photoreceptor Degeneration in Zebrafish. Invest Ophthalmol Vis Sci 2020; 61:24. [PMID: 32687549 PMCID: PMC7425700 DOI: 10.1167/iovs.61.8.24] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 06/13/2020] [Indexed: 02/06/2023] Open
Abstract
Purpose Mutations in TMEM216, a ciliary transition zone tetraspan transmembrane protein, are linked to Joubert syndrome and Meckel syndrome. Photoreceptor degeneration is a prominent phenotype in Joubert syndrome. How TMEM216 contributes to photoreceptor health is poorly understood. Methods We have generated tmem216 knockout zebrafish by CRISPR genome editing. The impact of TMEM216 deletion on photoreceptors was evaluated by immunofluorescence staining and electron microscopy. Results Homozygous tmem216 knockout zebrafish died before 21 days after fertilization. Their retina exhibited reduced immunoreactivity to rod photoreceptor outer segment marker 4D2 and cone photoreceptor outer segment marker G protein subunit α transducin 2 (GNAT2). Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) revealed an increase in TUNEL-positive nuclei in the knockout retina, indicating photoreceptor degeneration. The tmem216 mutation resulted in shortened photoreceptor ciliary axoneme, as revealed by acetylated α-tubulin immunostaining. Photoreceptors in knockout zebrafish exhibited mislocalization of outer segment proteins such as rhodopsin, GNAT2, and red opsin to the inner segment and cell bodies. Additionally, electron microscopy revealed that the mutant photoreceptors elaborated outer segment with abnormal disc morphology such as shortened discs and vesicles/vacuoles within the outer segment. Conclusion Our results indicate that TMEM216 is essential for normal genesis of outer segment disc structures, transport of outer segment materials, and survival of photoreceptors in zebrafish. These tmem216 knockout zebrafish will be useful in studying how transition zone proteins regulate photoreceptor outer segment formation and maintenance.
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Affiliation(s)
- Yu Liu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, New York, United States
| | - Shuqin Cao
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, New York, United States
| | - Miao Yu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, New York, United States
| | - Huaiyu Hu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, New York, United States
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15
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Calvo E, Milla-Navarro S, Ortuño-Lizarán I, Gómez-Vicente V, Cuenca N, De la Villa P, Germain F. Deleterious Effect of NMDA Plus Kainate on the Inner Retinal Cells and Ganglion Cell Projection of the Mouse. Int J Mol Sci 2020; 21:ijms21051570. [PMID: 32106602 PMCID: PMC7084685 DOI: 10.3390/ijms21051570] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 02/21/2020] [Accepted: 02/22/2020] [Indexed: 12/24/2022] Open
Abstract
Combined administration of N-Methyl-D-Aspartate (NMDA) and kainic acid (KA) on the inner retina was studied as a model of excitotoxicity. The right eye of C57BL6J mice was injected with 1 µL of PBS containing NMDA 30 mM and KA 10 mM. Only PBS was injected in the left eye. One week after intraocular injection, electroretinogram recordings and immunohistochemistry were performed on both eyes. Retinal ganglion cell (RGC) projections were studied by fluorescent-cholerotoxin anterograde labeling. A clear decrease of the retinal "b" wave amplitude, both in scotopic and photopic conditions, was observed in the eyes injected with NMDA/KA. No significant effect on the "a" wave amplitude was observed, indicating the preservation of photoreceptors. Immunocytochemical labeling showed no effects on the outer nuclear layer, but a significant thinning on the inner retinal layers, thus indicating that NMDA and KA induce a deleterious effect on bipolar, amacrine and ganglion cells. Anterograde tracing of the visual pathway after NMDA and KA injection showed the absence of RGC projections to the contralateral superior colliculus and lateral geniculate nucleus. We conclude that glutamate receptor agonists, NMDA and KA, induce a deleterious effect of the inner retina when injected together into the vitreous chamber.
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Affiliation(s)
- Estrella Calvo
- Department of Systems Biology, University of Alcalá, 28871 Madrid, Spain (P.D.l.V.)
| | | | - Isabel Ortuño-Lizarán
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain
| | - Violeta Gómez-Vicente
- Department of Optics, Pharmacology and Anatomy, University of Alicante, 03690 Alicante, Spain;
| | - Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain
| | - Pedro De la Villa
- Department of Systems Biology, University of Alcalá, 28871 Madrid, Spain (P.D.l.V.)
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain
| | - Francisco Germain
- Department of Systems Biology, University of Alcalá, 28871 Madrid, Spain (P.D.l.V.)
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), 28034 Madrid, Spain
- Correspondence:
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16
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Murphy DP, Hughes AEO, Lawrence KA, Myers CA, Corbo JC. Cis-regulatory basis of sister cell type divergence in the vertebrate retina. eLife 2019; 8:e48216. [PMID: 31633482 PMCID: PMC6802965 DOI: 10.7554/elife.48216] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 09/19/2019] [Indexed: 12/27/2022] Open
Abstract
Multicellular organisms evolved via repeated functional divergence of transcriptionally related sister cell types, but the mechanisms underlying sister cell type divergence are not well understood. Here, we study a canonical pair of sister cell types, retinal photoreceptors and bipolar cells, to identify the key cis-regulatory features that distinguish them. By comparing open chromatin maps and transcriptomic profiles, we found that while photoreceptor and bipolar cells have divergent transcriptomes, they share remarkably similar cis-regulatory grammars, marked by enrichment of K50 homeodomain binding sites. However, cell class-specific enhancers are distinguished by enrichment of E-box motifs in bipolar cells, and Q50 homeodomain motifs in photoreceptors. We show that converting K50 motifs to Q50 motifs represses reporter expression in bipolar cells, while photoreceptor expression is maintained. These findings suggest that partitioning of Q50 motifs within cell type-specific cis-regulatory elements was a critical step in the evolutionary divergence of the bipolar transcriptome from that of photoreceptors.
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Affiliation(s)
- Daniel P Murphy
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisUnited States
| | - Andrew EO Hughes
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisUnited States
| | - Karen A Lawrence
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisUnited States
| | - Connie A Myers
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisUnited States
| | - Joseph C Corbo
- Department of Pathology and ImmunologyWashington University School of MedicineSt. LouisUnited States
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17
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Yamashita K, Yagi T, Isono T, Nishiyama Y, Hashimoto M, Yamada K, Suzuki K, Tokunaga E. Absorbance spectra of the hematochrome-like granules and eyespot of Euglena gracilis by scan-free absorbance spectral imaging A(x, y, λ) within the live cells. J Plant Res 2019; 132:431-438. [PMID: 30980216 DOI: 10.1007/s10265-019-01102-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 03/10/2019] [Indexed: 06/09/2023]
Abstract
Euglena gracilis has an organelle resembling hematochrome, with an appearance similar to the eyespot and the absorption band spectrally overlapped with that of the carotenoid. To discriminate the hematochrome-like granules and eyespot, scan-free, non-invasive, absorbance spectral imaging A(x, y, λ) microscopy of single live cells, where A(x, y, λ) means absorbance at a position (x, y) on a two-dimensional image at a specific wavelength λ was applied. This technique was demonstrated to be a powerful tool for basic research on intracellular structural analysis. By this method, characteristic absorption spectra specific to the hematochrome-like granule or eyespot were identified among a variety of spectra observed depending on the location inside the organelles. The hematochrome-like granule was dark orange and deep green in its outline and had a characteristic absorption peak at 620 nm as well as at 676 to 698 nm, suggesting that its origin is a component of chloroplast including chlorophyll a. Furthermore, the representative spectra of these organelles were derived by principal component analysis of the absorbance and its position in absorbance image, indicating that they can be distinguished from each other and other regions. It was also confirmed that even in areas where these organelles and chloroplasts overlap, one can distinguish them from each other. The present research clarified the absorption spectra of the eyespot with 1 × 1 µm spatial resolution and those unpublished of hematochrome-like granules of E. gracilis, and indicated that one can statistically distinguish these organelles by this method.
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Affiliation(s)
- Kyohei Yamashita
- Department of Physics, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Takafumi Yagi
- Department of Physics, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Takumi Isono
- Department of Physics, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Yusuke Nishiyama
- Department of Physics, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Masafumi Hashimoto
- Department of Physics, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan
| | - Koji Yamada
- euglena Co., Ltd., Yokohama-shi, Kanagawa, Japan
| | - Kengo Suzuki
- euglena Co., Ltd., Yokohama-shi, Kanagawa, Japan
| | - Eiji Tokunaga
- Department of Physics, Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan.
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18
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Abstract
Sea urchins can detect and respond to light, and many species of sea urchins are negatively phototaxic. Light detection is hypothesized to occur via photoreceptors located on sea urchin tube feet, and opsins have been detected in tube feet, spines, and the test. However, the molecular mechanisms underlying light detection are, for the most part, unknown. Individual tube feet disc cells were isolated from purple sea urchins (Strongylocentrotus purpuratus), and the electrical responses of these cells to varying levels of illumination were quantified using the patch clamp technique. No currents were observed under bright illumination, whereas under dark conditions, large, slowly activating currents were consistently observed. Two types of cells were functionally identified based on their responses to darkness. Type I cells sustained currents indefinitely in the dark, whereas Type II cell currents spontaneously decayed after several seconds. The large currents observed were composed of the summation of many smaller events that were characterized by a rapid onset and an exponentially decaying component, which may be indicative of direct vesicular release from the tube feet disc cells in response to the dark conditions.
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19
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Pérez JH, Tolla E, Dunn IC, Meddle SL, Stevenson TJ. A Comparative Perspective on Extra-retinal Photoreception. Trends Endocrinol Metab 2019; 30:39-53. [PMID: 30522810 DOI: 10.1016/j.tem.2018.10.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/25/2018] [Accepted: 10/26/2018] [Indexed: 12/20/2022]
Abstract
Ubiquitous in non-mammalian vertebrates, extra-retinal photoreceptors (ERPs) have been linked to an array of physiological, metabolic, behavioral, and morphological changes. However, the mechanisms and functional roles of ERPs remain one of the enduring questions of modern biology. In this review article, we use a comparative framework to identify conserved roles and distributions of ERPs, highlighting knowledge gaps. We conclude that ERP research can be divided into two largely unconnected categories: (i) identification and localization of photoreceptors and (ii) linkage of non-retinal light reception to behavioral and physiological processes, particularly endocrine systems. However, the emergence of novel gene editing and silencing techniques is enabling the unification of ERP research by allowing the bridging of this divide.
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Affiliation(s)
- Jonathan H Pérez
- Institute for Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3FX, Scotland; The Roslin Institute, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, Scotland.
| | - Elisabetta Tolla
- Institute for Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3FX, Scotland
| | - Ian C Dunn
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, Scotland
| | - Simone L Meddle
- The Roslin Institute, The Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian EH25 9RG, Scotland
| | - Tyler J Stevenson
- Institute for Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 3FX, Scotland
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20
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Chen MY, Liu HP, Liu CH, Cheng J, Chang MS, Chiang SY, Liao WP, Lin WY. DEHP toxicity on vision, neuromuscular junction, and courtship behaviors of Drosophila. Environ Pollut 2018; 243:1558-1567. [PMID: 30293038 DOI: 10.1016/j.envpol.2018.09.063] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 09/10/2018] [Accepted: 09/11/2018] [Indexed: 06/08/2023]
Abstract
Bis(2-ethylhexyl) phthalate (DEHP) is the most common plasticizer. Previous studies have shown DEHP treatment accelerates neurological degeneration, suggesting that DEHP may impact retinal sensitivity to light, neurotransmission, and copulation behaviors. Although its neurotoxicity and antifertility properties have been studied, whether DEHP exposure disrupts vision and how DEHP influences neuromuscular junction (NMJ) have not been reported yet. Moreover, the impact of DEHP on insect courtship behavior is still elusive. Fruit flies (Drosophila melanogaster) were treated with series concentrations of DEHP and observed for lifespan, motor function, electroretinogram (ERG), electrophysiology of neuromuscular junction (NMJ), courtship behaviors, and relevant gene expression. Our results confirmed the DEHP toxicity on lifespan and capacity of motor function and updated its effect on copulation behaviors. Additionally, we report for the first time that DEHP exposure may harm vision by affecting the synaptic signaling between the photoreceptor and the laminar neurons. Further, DEHP treatment altered both spontaneous and evoked neurotransmission properties. Noteworthy, the effect of DEHP exposure on the copulation behavior is sex-dependent, and we proposed potential mechanisms for future investigation.
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Affiliation(s)
- Mei-Ying Chen
- Department of Environmental Engineering, National Chung Hsing University, Taichung, 402, Taiwan
| | - Hsin-Ping Liu
- Graduate Institute of Acupuncture Science, College of Chinese Medicine, China Medical University, Taichung, 40402, Taiwan; Department of Bioinformatics and Medical Engineering, Asia University, Taichung, 41354, Taiwan
| | - Chuan-Hsiu Liu
- School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, 40402, Taiwan
| | - Jack Cheng
- Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung, 40402, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung, 40447, Taiwan
| | - Meng-Shiun Chang
- Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung, 40402, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung, 40447, Taiwan
| | - Su-Yin Chiang
- School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, 40402, Taiwan
| | - Wing-Ping Liao
- Department of Environmental Engineering, National Chung Hsing University, Taichung, 402, Taiwan.
| | - Wei-Yong Lin
- Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung, 40402, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung, 40447, Taiwan; Brain Diseases Research Center, China Medical University, Taichung, 40402, Taiwan.
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21
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Moehlman AT, Casey AK, Servage K, Orth K, Krämer H. Adaptation to constant light requires Fic-mediated AMPylation of BiP to protect against reversible photoreceptor degeneration. eLife 2018; 7:e38752. [PMID: 30015618 PMCID: PMC6066327 DOI: 10.7554/elife.38752] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 07/16/2018] [Indexed: 12/13/2022] Open
Abstract
In response to environmental, developmental, and pathological stressors, cells engage homeostatic pathways to maintain their function. Among these pathways, the Unfolded Protein Response protects cells from the accumulation of misfolded proteins in the ER. Depending on ER stress levels, the ER-resident Fic protein catalyzes AMPylation or de-AMPylation of BiP, the major ER chaperone and regulator of the Unfolded Protein Response. This work elucidates the importance of the reversible AMPylation of BiP in maintaining the Drosophila visual system in response to stress. After 72 hr of constant light, photoreceptors of fic-null and AMPylation-resistant BiPT366A mutants, but not wild-type flies, display loss of synaptic function, disintegration of rhabdomeres, and excessive activation of ER stress reporters. Strikingly, this phenotype is reversible: photoreceptors regain their structure and function within 72 hr once returned to a standard light:dark cycle. These findings show that Fic-mediated AMPylation of BiP is required for neurons to adapt to transient stress demands.
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Affiliation(s)
- Andrew T Moehlman
- Department of NeuroscienceUT Southwestern Medical CenterDallasUnited States
| | - Amanda K Casey
- Department of Molecular BiologyUT Southwestern Medical CenterDallasUnited States
| | - Kelly Servage
- Department of Molecular BiologyUT Southwestern Medical CenterDallasUnited States
- Department of BiochemistryUT Southwestern Medical CenterDallasUnited States
- Howard Hughes Medical InstituteDallasUnited States
| | - Kim Orth
- Department of Molecular BiologyUT Southwestern Medical CenterDallasUnited States
- Department of BiochemistryUT Southwestern Medical CenterDallasUnited States
- Howard Hughes Medical InstituteDallasUnited States
| | - Helmut Krämer
- Department of NeuroscienceUT Southwestern Medical CenterDallasUnited States
- Department of Cell BiologyUT Southwestern Medical CenterDallasUnited States
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22
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Wen X, Van Hook MJ, Grassmeyer JJ, Wiesman AI, Rich GM, Cork KM, Thoreson WB. Endocytosis sustains release at photoreceptor ribbon synapses by restoring fusion competence. J Gen Physiol 2018; 150:591-611. [PMID: 29555658 PMCID: PMC5881445 DOI: 10.1085/jgp.201711919] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/21/2018] [Indexed: 01/15/2023] Open
Abstract
Endocytosis is an essential process at sites of synaptic release. Not only are synaptic vesicles recycled by endocytosis, but the removal of proteins and lipids by endocytosis is needed to restore release site function at active zones after vesicle fusion. Synaptic exocytosis from vertebrate photoreceptors involves synaptic ribbons that serve to cluster vesicles near the presynaptic membrane. In this study, we hypothesize that this clustering increases the likelihood that exocytosis at one ribbon release site may disrupt release at an adjacent site and therefore that endocytosis may be particularly important for restoring release site competence at photoreceptor ribbon synapses. To test this, we combined optical and electrophysiological techniques in salamander rods. Pharmacological inhibition of dynamin-dependent endocytosis rapidly inhibits release from synaptic ribbons and slows recovery of ribbon-mediated release from paired pulse synaptic depression. Inhibiting endocytosis impairs the ability of second-order horizontal cells to follow rod light responses at frequencies as low as 2 Hz. Inhibition of endocytosis also increases lateral membrane mobility of individual Ca2+ channels, showing that it changes release site structure. Visualization of single synaptic vesicles by total internal reflection fluorescence microscopy reveals that inhibition of endocytosis reduces the likelihood of fusion among vesicles docked near ribbons and increases the likelihood that they will retreat from the membrane without fusion. Vesicle advance toward the membrane is also reduced, but the number of membrane-associated vesicles is not. Endocytosis therefore appears to be more important for restoring later steps in vesicle fusion than for restoring docking. Unlike conventional synapses in which endocytic restoration of release sites is evident only at high frequencies, endocytosis is needed to maintain release from rod ribbon synapses even at modest frequencies.
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Affiliation(s)
- Xiangyi Wen
- Department of Ophthalmology & Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE
- Department of Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE
| | - Matthew J Van Hook
- Department of Ophthalmology & Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE
| | - Justin J Grassmeyer
- Department of Ophthalmology & Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE
- Department of Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE
| | - Alex I Wiesman
- Department of Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE
| | - Grace M Rich
- Department of Ophthalmology & Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE
| | - Karlene M Cork
- Department of Ophthalmology & Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE
- Department of Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE
| | - Wallace B Thoreson
- Department of Ophthalmology & Visual Sciences, Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE
- Department of Pharmacology & Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE
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23
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Zele AJ, Feigl B, Adhikari P, Maynard ML, Cao D. Melanopsin photoreception contributes to human visual detection, temporal and colour processing. Sci Rep 2018; 8:3842. [PMID: 29497109 PMCID: PMC5832793 DOI: 10.1038/s41598-018-22197-w] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 02/14/2018] [Indexed: 12/27/2022] Open
Abstract
The visual consequences of melanopsin photoreception in humans are not well understood. Here we studied melanopsin photoreception using a technique of photoreceptor silent substitution with five calibrated spectral lights after minimising the effects of individual differences in optical pre-receptoral filtering and desensitising penumbral cones in the shadow of retinal blood vessels. We demonstrate that putative melanopsin-mediated image-forming vision corresponds to an opponent S-OFF L + M-ON response property, with an average temporal resolution up to approximately 5 Hz, and >10x higher thresholds than red-green colour vision. With a capacity for signalling colour and integrating slowly changing lights, melanopsin-expressing intrinsically photosensitive retinal ganglion cells maybe the fifth photoreceptor type for peripheral vision.
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Affiliation(s)
- Andrew J Zele
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia.
- School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, Australia.
| | - Beatrix Feigl
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
- School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Australia
- Queensland Eye Institute, Brisbane, Australia
| | - Prakash Adhikari
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
- School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, Australia
| | - Michelle L Maynard
- Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
- School of Optometry and Vision Science, Queensland University of Technology (QUT), Brisbane, Australia
- School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, Australia
| | - Dingcai Cao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, USA
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24
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Himmelberg MM, West RJH, Elliott CJH, Wade AR. Abnormal visual gain control and excitotoxicity in early-onset Parkinson's disease Drosophila models. J Neurophysiol 2018; 119:957-970. [PMID: 29142100 PMCID: PMC5899316 DOI: 10.1152/jn.00681.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 11/13/2017] [Accepted: 11/13/2017] [Indexed: 12/17/2022] Open
Abstract
The excitotoxic theory of Parkinson's disease (PD) hypothesizes that a pathophysiological degeneration of dopaminergic neurons stems from neural hyperactivity at early stages of disease, leading to mitochondrial stress and cell death. Recent research has harnessed the visual system of Drosophila PD models to probe this hypothesis. Here, we investigate whether abnormal visual sensitivity and excitotoxicity occur in early-onset PD (EOPD) Drosophila models DJ-1αΔ72, DJ-1βΔ 93, and PINK15. We used an electroretinogram to record steady-state visually evoked potentials driven by temporal contrast stimuli. At 1 day of age, all EOPD mutants had a twofold increase in response amplitudes compared with w̄ controls. Furthermore, we found that excitotoxicity occurs in older EOPD models after increased neural activity is triggered by visual stimulation. In an additional analysis, we used a linear discriminant analysis to test whether there were subtle variations in neural gain control that could be used to classify Drosophila into their correct age and genotype. The discriminant analysis was highly accurate, classifying Drosophila into their correct genotypic class at all age groups at 50-70% accuracy (20% chance baseline). Differences in cellular processes link to subtle alterations in neural network operation in young flies, all of which lead to the same pathogenic outcome. Our data are the first to quantify abnormal gain control and excitotoxicity in EOPD Drosophila mutants. We conclude that EOPD mutations may be linked to more sensitive neuronal signaling in prodromal animals that may cause the expression of PD symptomologies later in life. NEW & NOTEWORTHY Steady-state visually evoked potential response amplitudes to multivariate temporal contrast stimuli were recorded in early-onset PD Drosophila models. Our data indicate that abnormal gain control and a subsequent visual loss occur in these PD mutants, supporting a broader excitotoxicity hypothesis in genetic PD. Furthermore, linear discriminant analysis could accurately classify Drosophila into their correct genotype at different ages throughout their lifespan. Our results suggest increased neural signaling in prodromal PD patients.
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Affiliation(s)
- Marc M Himmelberg
- Department of Psychology, The University of York , York , United Kingdom
| | - Ryan J H West
- Department of Biology, The University of York , York , United Kingdom
| | | | - Alex R Wade
- Department of Psychology, The University of York , York , United Kingdom
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Wang S, Borst A, Zaslavsky N, Tishby N, Segev I. Efficient encoding of motion is mediated by gap junctions in the fly visual system. PLoS Comput Biol 2017; 13:e1005846. [PMID: 29206224 PMCID: PMC5730180 DOI: 10.1371/journal.pcbi.1005846] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 12/14/2017] [Accepted: 10/16/2017] [Indexed: 01/10/2023] Open
Abstract
Understanding the computational implications of specific synaptic connectivity patterns is a fundamental goal in neuroscience. In particular, the computational role of ubiquitous electrical synapses operating via gap junctions remains elusive. In the fly visual system, the cells in the vertical-system network, which play a key role in visual processing, primarily connect to each other via axonal gap junctions. This network therefore provides a unique opportunity to explore the functional role of gap junctions in sensory information processing. Our information theoretical analysis of a realistic VS network model shows that within 10 ms following the onset of the visual input, the presence of axonal gap junctions enables the VS system to efficiently encode the axis of rotation, θ, of the fly’s ego motion. This encoding efficiency, measured in bits, is near-optimal with respect to the physical limits of performance determined by the statistical structure of the visual input itself. The VS network is known to be connected to downstream pathways via a subset of triplets of the vertical system cells; we found that because of the axonal gap junctions, the efficiency of this subpopulation in encoding θ is superior to that of the whole vertical system network and is robust to a wide range of signal to noise ratios. We further demonstrate that this efficient encoding of motion by this subpopulation is necessary for the fly's visually guided behavior, such as banked turns in evasive maneuvers. Because gap junctions are formed among the axons of the vertical system cells, they only impact the system’s readout, while maintaining the dendritic input intact, suggesting that the computational principles implemented by neural circuitries may be much richer than previously appreciated based on point neuron models. Our study provides new insights as to how specific network connectivity leads to efficient encoding of sensory stimuli. Understanding sensory stimuli from the environment and deciding how best to respond to it behaviorally is essential for survival. What makes organisms efficient in encoding these sensory stimuli? This study provides a novel view on this unresolved issue using the visual system of the fly. We show that a specific synaptic connectivity manifested via gap junctions (GJs) among axons in the Vertical System (VS) network leads to particularly high encoding efficiency of the axis of rotation of the fly’s ego motion. Due to these GJs, triplets of VS neurons (the VS5-6-7 triplet), which connect to a downstream motor system, encode motion stimuli at an efficiency close to the physical limit; this efficient encoding is necessary for evasive maneuvers that are critical for the fly to escape predators. We then suggest why GJs in the VS network enable such high encoding efficiency.
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Affiliation(s)
- Siwei Wang
- Department of Neurobiology, Hebrew University Jerusalem, Jerusalem, Israel
- * E-mail:
| | - Alexander Borst
- Max Planck Institute of Neurobiology, Martinstried, Munich, Germany
| | - Noga Zaslavsky
- The Edmond and Lily Safra Center for Brain Sciences, Hebrew University Jerusalem, Jerusalem, Israel
| | - Naftali Tishby
- The Edmond and Lily Safra Center for Brain Sciences, Hebrew University Jerusalem, Jerusalem, Israel
- Department of Computer Science, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Idan Segev
- Department of Neurobiology, Hebrew University Jerusalem, Jerusalem, Israel
- Max Planck Institute of Neurobiology, Martinstried, Munich, Germany
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Petralia RS, Wang YX, Mattson MP, Yao PJ. Invaginating Presynaptic Terminals in Neuromuscular Junctions, Photoreceptor Terminals, and Other Synapses of Animals. Neuromolecular Med 2017; 19:193-240. [PMID: 28612182 PMCID: PMC6518423 DOI: 10.1007/s12017-017-8445-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 06/01/2017] [Indexed: 10/19/2022]
Abstract
Typically, presynaptic terminals form a synapse directly on the surface of postsynaptic processes such as dendrite shafts and spines. However, some presynaptic terminals invaginate-entirely or partially-into postsynaptic processes. We survey these invaginating presynaptic terminals in all animals and describe several examples from the central nervous system, including giant fiber systems in invertebrates, and cup-shaped spines, electroreceptor synapses, and some specialized auditory and vestibular nerve terminals in vertebrates. We then examine mechanoreceptors and photoreceptors, concentrating on the complex of pre- and postsynaptic processes found in basal invaginations of the cell. We discuss in detail the role of vertebrate invaginating horizontal cell processes in both chemical and electrical feedback mechanisms. We also discuss the common presence of indenting or invaginating terminals in neuromuscular junctions on muscles of most kinds of animals, and especially discuss those of Drosophila and vertebrates. Finally, we consider broad questions about the advantages of possessing invaginating presynaptic terminals and describe some effects of aging and disease, especially on neuromuscular junctions. We suggest that the invagination is a mechanism that can enhance both chemical and electrical interactions at the synapse.
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Affiliation(s)
- Ronald S Petralia
- Advanced Imaging Core, NIDCD/NIH, 35A Center Drive, Room 1E614, Bethesda, MD, 20892-3729, USA.
| | - Ya-Xian Wang
- Advanced Imaging Core, NIDCD/NIH, 35A Center Drive, Room 1E614, Bethesda, MD, 20892-3729, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, NIA/NIH, Baltimore, MD, 21224, USA
| | - Pamela J Yao
- Laboratory of Neurosciences, NIA/NIH, Baltimore, MD, 21224, USA
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Abstract
BACKGROUND Fundamental spatial vision capabilities of visual systems can be characterized by their contrast sensitivity and visual acuity. OBJECTIVE Comparison of contrast sensitivity and visual acuity in humans and other animals. MATERIAL AND METHODS An analysis of known contrast sensitivity functions and maximum visual acuity across selected taxa was carried out, with consideration of measurement principles, viewing conditions and allometry. RESULTS Comparing across all analyzed species, contrast sensitivity functions have inverted U‑shape characteristics, with key differences in both position and absolute sensitivity within the spectrum of spatial frequencies. Humans, for example, have a maximum sensitivity at 5 cycles/degree and mice at approximately 0.1 cycles/degree. Body and eye size generally correlate well with maximum visual acuity. Across eye types, lens eyes have the highest optical and visual resolution, all other things being equal. Diurnal species typically outperform crepuscular or nocturnal species. Humans generally excel at both maximum contrast sensitivity as well as visual acuity. CONCLUSION Despite great differences in optical, anatomical and neurophysiological structures between humans and animals, spatial vision capabilities are generally comparable across taxa. This favors the hypothesis that spatial vision in animals develops primarily towards meeting similar evolutionary needs within the limits of biophysical and optical laws.
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Affiliation(s)
- W M Harmening
- Universitäts-Augenklinik Bonn, Ernst-Abbe-Str. 2, 53127, Bonn, Deutschland.
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Santer RD. Developing photoreceptor-based models of visual attraction in riverine tsetse, for use in the engineering of more-attractive polyester fabrics for control devices. PLoS Negl Trop Dis 2017; 11:e0005448. [PMID: 28306721 PMCID: PMC5371378 DOI: 10.1371/journal.pntd.0005448] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 03/29/2017] [Accepted: 03/01/2017] [Indexed: 11/19/2022] Open
Abstract
Riverine tsetse transmit the parasites that cause the most prevalent form of human African trypanosomiasis, Gambian HAT. In response to the imperative for cheap and efficient tsetse control, insecticide-treated 'tiny targets' have been developed through refinement of tsetse attractants based on blue fabric panels. However, modern blue polyesters used for this purpose attract many less tsetse than traditional phthalogen blue cottons. Therefore, colour engineering polyesters for improved attractiveness has great potential for tiny target development. Because flies have markedly different photoreceptor spectral sensitivities from humans, and the responses of these photoreceptors provide the inputs to their visually guided behaviours, it is essential that polyester colour engineering be guided by fly photoreceptor-based explanations of tsetse attraction. To this end, tsetse attraction to differently coloured fabrics was recently modelled using the calculated excitations elicited in a generic set of fly photoreceptors as predictors. However, electrophysiological data from tsetse indicate the potential for modified spectral sensitivities versus the generic pattern, and processing of fly photoreceptor responses within segregated achromatic and chromatic channels has long been hypothesised. Thus, I constructed photoreceptor-based models explaining the attraction of G. f. fuscipes to differently coloured tiny targets recorded in a previously published investigation, under differing assumptions about tsetse spectral sensitivities and organisation of visual processing. Models separating photoreceptor responses into achromatic and chromatic channels explained attraction better than earlier models combining weighted photoreceptor responses in a single mechanism, regardless of the spectral sensitivities assumed. However, common principles for fabric colour engineering were evident across the complete set of models examined, and were consistent with earlier work. Tools for the calculation of fly photoreceptor excitations are available with this paper, and the ways in which these and photoreceptor-based models of attraction can provide colorimetric values for the engineering of more-attractively coloured polyester fabrics are discussed.
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Affiliation(s)
- Roger D. Santer
- Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Aberystwyth, Ceredigion, SY23 3FG United Kingdom
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Bitton PP, Janisse K, Doucet SM. Assessing Sexual Dicromatism: The Importance of Proper Parameterization in Tetrachromatic Visual Models. PLoS One 2017; 12:e0169810. [PMID: 28076391 PMCID: PMC5226829 DOI: 10.1371/journal.pone.0169810] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 12/21/2016] [Indexed: 11/19/2022] Open
Abstract
Perceptual models of animal vision have greatly contributed to our understanding of animal-animal and plant-animal communication. The receptor-noise model of color contrasts has been central to this research as it quantifies the difference between two colors for any visual system of interest. However, if the properties of the visual system are unknown, assumptions regarding parameter values must be made, generally with unknown consequences. In this study, we conduct a sensitivity analysis of the receptor-noise model using avian visual system parameters to systematically investigate the influence of variation in light environment, photoreceptor sensitivities, photoreceptor densities, and light transmission properties of the ocular media and the oil droplets. We calculated the chromatic contrast of 15 plumage patches to quantify a dichromatism score for 70 species of Galliformes, a group of birds that display a wide range of sexual dimorphism. We found that the photoreceptor densities and the wavelength of maximum sensitivity of the short-wavelength-sensitive photoreceptor 1 (SWS1) can change dichromatism scores by 50% to 100%. In contrast, the light environment, transmission properties of the oil droplets, transmission properties of the ocular media, and the peak sensitivities of the cone photoreceptors had a smaller impact on the scores. By investigating the effect of varying two or more parameters simultaneously, we further demonstrate that improper parameterization could lead to differences between calculated and actual contrasts of more than 650%. Our findings demonstrate that improper parameterization of tetrachromatic visual models can have very large effects on measures of dichromatism scores, potentially leading to erroneous inferences. We urge more complete characterization of avian retinal properties and recommend that researchers either determine whether their species of interest possess an ultraviolet or near-ultraviolet sensitive SWS1 photoreceptor, or present models for both.
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Affiliation(s)
- Pierre-Paul Bitton
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada
- * E-mail:
| | - Kevyn Janisse
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada
| | - Stéphanie M. Doucet
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, Canada
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Keenan WT, Rupp AC, Ross RA, Somasundaram P, Hiriyanna S, Wu Z, Badea TC, Robinson PR, Lowell BB, Hattar SS. A visual circuit uses complementary mechanisms to support transient and sustained pupil constriction. eLife 2016; 5:e15392. [PMID: 27669145 PMCID: PMC5079752 DOI: 10.7554/elife.15392] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 09/22/2016] [Indexed: 12/22/2022] Open
Abstract
Rapid and stable control of pupil size in response to light is critical for vision, but the neural coding mechanisms remain unclear. Here, we investigated the neural basis of pupil control by monitoring pupil size across time while manipulating each photoreceptor input or neurotransmitter output of intrinsically photosensitive retinal ganglion cells (ipRGCs), a critical relay in the control of pupil size. We show that transient and sustained pupil responses are mediated by distinct photoreceptors and neurotransmitters. Transient responses utilize input from rod photoreceptors and output by the classical neurotransmitter glutamate, but adapt within minutes. In contrast, sustained responses are dominated by non-conventional signaling mechanisms: melanopsin phototransduction in ipRGCs and output by the neuropeptide PACAP, which provide stable pupil maintenance across the day. These results highlight a temporal switch in the coding mechanisms of a neural circuit to support proper behavioral dynamics.
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Affiliation(s)
| | - Alan C Rupp
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Rachel A Ross
- Department of Psychiatry, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Department of Psychiatry, Massachusetts General Hospital, Boston, United States
| | - Preethi Somasundaram
- Department of Biological Sciences, University of Marlyand, Baltimore, United States
| | - Suja Hiriyanna
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Zhijian Wu
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Tudor C Badea
- National Eye Institute, National Institutes of Health, Bethesda, United States
| | - Phyllis R Robinson
- Department of Biological Sciences, University of Marlyand, Baltimore, United States
| | - Bradford B Lowell
- Division of Endocrinology, Diabetes, and Metabolism, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, United States
- Program in Neuroscience, Harvard Medical School, Boston, United States
| | - Samer S Hattar
- Department of Biology, Johns Hopkins University, Baltimore, United States
- Department of Neuroscience, Johns Hopkins University, Baltimore, United States
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Abstract
A theory is presented that explains the evolution of the pinealocyte from the common ancestral photoreceptor of both the pinealocyte and retinal photoreceptor. Central to the hypothesis is the previously unrecognized conflict between the two chemistries that define these cells—melatonin synthesis and retinoid recycling. At the core of the conflict is the formation of adducts composed of two molecules of retinaldehyde and one molecule of serotonin, analogous to formation in the retina of the toxic bis-retinyl ethanolamine (A2E). The hypothesis argues that early in chordate evolution, at a point before the genes required for melatonin synthesis were acquired, retinaldehyde—which is essential for photon capture—was depleted by reacting with naturally occurring arylalkylamines (tyramine, serotonin, tryptamine, phenylethylamine) and xenobiotic arylalkylamines. This generated toxic bis-retinyl arylalkylamines (A2AAs). The acquisition of arylalkylamine N-acetyltransferase (AANAT) prevented this by N-acetylating the arylalkylamines. HydroxyindoleOmethyltransferase enhanced detoxification in the primitive photoreceptor by increasing the lipid solubility of serotonin and bis-retinyl serotonin. After the serotonin. melatonin pathway was established, the next step leading toward the pinealocyte was the evolution of a daily rhythm in melatonin and the capacity to recognize it as a signal of darkness. The shift in melatonin from metabolic garbage to information developed a pressure to improve the reliability of the melatonin signal, which in turn led to higher levels of serotonin in the photodetector. This generated the conflict between serotonin and retinaldehyde, which was resolved by the cellular segregation of the two chemistries. The result, in primates, is a pineal gland that does not detect light and a retinal photodetector that does not make melatonin. High levels of AANAT in the latter tissue might serve the same function AANAT had when first acquired— prevention of A2AA formation.
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Affiliation(s)
- David C Klein
- Section on Neuroendocrinology, Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-4480, USA.
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Gruber DF, Loew ER, Deheyn DD, Akkaynak D, Gaffney JP, Smith WL, Davis MP, Stern JH, Pieribone VA, Sparks JS. Biofluorescence in Catsharks (Scyliorhinidae): Fundamental Description and Relevance for Elasmobranch Visual Ecology. Sci Rep 2016; 6:24751. [PMID: 27109385 PMCID: PMC4843165 DOI: 10.1038/srep24751] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 04/05/2016] [Indexed: 01/01/2023] Open
Abstract
Biofluorescence has recently been found to be widespread in marine fishes, including sharks. Catsharks, such as the Swell Shark (Cephaloscyllium ventriosum) from the eastern Pacific and the Chain Catshark (Scyliorhinus retifer) from the western Atlantic, are known to exhibit bright green fluorescence. We examined the spectral sensitivity and visual characteristics of these reclusive sharks, while also considering the fluorescent properties of their skin. Spectral absorbance of the photoreceptor cells in these sharks revealed the presence of a single visual pigment in each species. Cephaloscyllium ventriosum exhibited a maximum absorbance of 484 ± 3 nm and an absorbance range at half maximum (λ1/2max) of 440-540 nm, whereas for S. retifer maximum absorbance was 488 ± 3 nm with the same absorbance range. Using the photoreceptor properties derived here, a "shark eye" camera was designed and developed that yielded contrast information on areas where fluorescence is anatomically distributed on the shark, as seen from other sharks' eyes of these two species. Phylogenetic investigations indicate that biofluorescence has evolved at least three times in cartilaginous fishes. The repeated evolution of biofluorescence in elasmobranchs, coupled with a visual adaptation to detect it; and evidence that biofluorescence creates greater luminosity contrast with the surrounding background, highlights the potential importance of biofluorescence in elasmobranch behavior and biology.
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Affiliation(s)
- David F. Gruber
- Baruch College, City University of New York, Department of Natural Sciences, New York, NY 10010, USA
- City University of New York, The Graduate Center, Program in Biology, New York, NY 10016, USA
- American Museum of Natural History, Sackler Institute for Comparative Genomics, New York, NY 10024, USA
| | - Ellis R. Loew
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Dimitri D. Deheyn
- University of California, San Diego, Scripps Institution of Oceanography, La Jolla, CA 92093, USA
| | - Derya Akkaynak
- University of Haifa, Charney School of Marine Sciences, Haifa, 3498838, Israel
- Interuniversity Institute of Marine Sciences, Eilat, 88103, Israel
| | - Jean P. Gaffney
- Baruch College, City University of New York, Department of Natural Sciences, New York, NY 10010, USA
| | - W. Leo Smith
- University of Kansas, Biodiversity Institute and Department of Ecology and Evolutionary Biology, Lawrence, KS 66049, USA
| | - Matthew P. Davis
- St. Cloud State University, Department of Biological Sciences, St. Cloud, MN 56301, USA
| | - Jennifer H. Stern
- University of Kansas, Biodiversity Institute and Department of Ecology and Evolutionary Biology, Lawrence, KS 66049, USA
| | - Vincent A. Pieribone
- The John B. Pierce Laboratory, Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06519, USA
| | - John S. Sparks
- American Museum of Natural History, Sackler Institute for Comparative Genomics, New York, NY 10024, USA
- American Museum of Natural History, Division of Vertebrate Zoology, Department of Ichthyology, New York, NY 10024, USA
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Servick K. REGENERATIVE MEDICINE. California stem cell agency plots a race to the clinic. Science 2016; 351:15. [PMID: 26721984 DOI: 10.1126/science.351.6268.15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Angbohang A, Wu N, Charalambous T, Eastlake K, Lei Y, Kim YS, Sun XH, Limb GA. Downregulation of the Canonical WNT Signaling Pathway by TGFβ1 Inhibits Photoreceptor Differentiation of Adult Human Müller Glia with Stem Cell Characteristics. Stem Cells Dev 2016; 25:1-12. [PMID: 26456050 PMCID: PMC4692127 DOI: 10.1089/scd.2015.0262] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/09/2015] [Indexed: 12/29/2022] Open
Abstract
Müller glia are responsible for the retina regeneration observed in zebrafish. Although the human retina harbors Müller glia with stem cell characteristics, there is no evidence that they regenerate the retina after disease or injury. Transforming growth factor-β (TGFβ) and Wnt signaling regulate retinal neurogenesis and inflammation, but their roles in the neural differentiation of human Müller stem cells (hMSC) are not known. We examined hMSC lines in vitro for the expression of various Wnt signaling components and for their modulation by TGFβ1, as well as the effect of this cytokine on the photoreceptor differentiation of these cells. Culture of hMSC with a combination of factors that induce photoreceptor differentiation of hMSC (FGF2, taurine, retinoic acid, and insulin-like growth factor type1; FTRI), markedly upregulated the expression of components of the canonical Wnt signaling pathway, including WNT2B, DKK1, and active β-CATENIN. Although FTRI did not modify mRNA expression of WNT5B, a component of the noncanonical/planar cell polarity Wnt pathway, it upregulated its secretion. Furthermore, TGFβ1 not only decreased WNT2B expression, but also inhibited FTRI-induced photoreceptor differentiation of hMSC, as determined by expression of the photoreceptor markers NR2E3, RHODOPSIN, and RECOVERIN. Inhibition of TGFβ1 signaling by an ALK5 inhibitor prevented TGFβ1-induced changes in the expression of the two Wnt ligands examined. More importantly, inhibition of the canonical WNT signaling by XAV-939 prevented FTRI-induced photoreceptor differentiation. These observations suggest that TGFβ may play a key role in preventing neural differentiation of hMSC and may constitute a potential target for induction of endogenous regeneration of the human retina.
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Affiliation(s)
- Angshumonik Angbohang
- Division of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, United Kingdom
| | - Na Wu
- Division of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, United Kingdom
- Department of Ophthalmology and Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Thalis Charalambous
- Division of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, United Kingdom
| | - Karen Eastlake
- Division of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, United Kingdom
| | - Yuan Lei
- Department of Ophthalmology and Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yung Su Kim
- Division of Ocular Biology and Therapeutics, UCL Institute of Ophthalmology, London, United Kingdom
| | - Xinghuai H. Sun
- Department of Ophthalmology and Visual Science, Eye & ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - G. Astrid Limb
- NIHR Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, United Kingdom
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Abstract
UVR8 is the only known plant photoreceptor that mediates light responses to UV-B (280-315 nm) of the solar spectrum. UVR8 perceives a UV-B signal via light-induced dimer dissociation, which triggers a wide range of cellular responses involved in photomorphogenesis and photoprotection. Two recent crystal structures of Arabidopsis thaliana UVR8 (AtUVR8) have revealed unusual clustering of UV-B-absorbing Trp pigments at the dimer interface and provided a structural framework for further mechanistic investigation. This review summarizes recent advances in spectroscopic, computational and crystallographic studies on UVR8 that are directed toward full understanding of UV-B perception at the molecular level.
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Affiliation(s)
- Xiaojing Yang
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
- Department of Ophthalmology and Vision Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Sherwin Montano
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Zhong Ren
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
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Abstract
Birds time their activities in synchronization with daily and seasonal periodicities in the environment, which is mainly provided by changes in day length (=photoperiod). Photoperiod appears to act at different levels than simply entraining the hypothalamic clock via eyes in birds. Photoreceptor cells that transmit light information to an avian brain are localized in three independent structures, the retina of eyes, pineal gland and hypothalamus, particularly in the paraventricular organ and lateral septal area. These hypothalamic photoreceptors are commonly referred to as encephalic or deep brain photoreceptors, DBPs. Eyes and pineal are known to contribute to the circadian regulation of behavior and physiology via rhythmic melatonin secretion in several birds. DBPs have been implicated in the regulation of seasonal physiology, particularly in photoperiod induced gonadal growth and development. Here, we briefly review limited evidence that is available on the roles of these photoreceptors in the regulation of circadian and seasonal physiology, with particular emphasis placed on the DBPs.
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Affiliation(s)
- Vinod Kumar
- DST-IRHPA Center for Excellence in Biological Rhythms Research and Indo US Center for Biological Timing, Department of Zoology, University of Delhi, Delhi 110 007, India.
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Dvoriantchikova G, Perea-Martinez I, Pappas S, Barry AF, Danek D, Dvoriantchikova X, Pelaez D, Ivanov D. Molecular Characterization of Notch1 Positive Progenitor Cells in the Developing Retina. PLoS One 2015; 10:e0131054. [PMID: 26091508 PMCID: PMC4474692 DOI: 10.1371/journal.pone.0131054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/28/2015] [Indexed: 12/02/2022] Open
Abstract
The oscillatory expression of Notch signaling in neural progenitors suggests that both repressors and activators of neural fate specification are expressed in the same progenitors. Since Notch1 regulates photoreceptor differentiation and contributes (together with Notch3) to ganglion cell fate specification, we hypothesized that genes encoding photoreceptor and ganglion cell fate activators would be highly expressed in Notch1 receptor-bearing (Notch1+) progenitors, directing these cells to differentiate into photoreceptors or into ganglion cells when Notch1 activity is diminished. To identify these genes, we used microarray analysis to study expression profiles of whole retinas and isolated from them Notch1+ cells at embryonic day 14 (E14) and postnatal day 0 (P0). To isolate Notch1+ cells, we utilized immunomagnetic cell separation. We also used Notch3 knockout (Notch3KO) animals to evaluate the contribution of Notch3 signaling in ganglion cell differentiation. Hierarchical clustering of 6,301 differentially expressed genes showed that Notch1+ cells grouped near the same developmental stage retina cluster. At E14, we found higher expression of repressors (Notch1, Hes5) and activators (Dll3, Atoh7, Otx2) of neuronal differentiation in Notch1+ cells compared to whole retinal cell populations. At P0, Notch1, Hes5, and Dll1 expression was significantly higher in Notch1+ cells than in whole retinas. Otx2 expression was more than thirty times higher than Atoh7 expression in Notch1+ cells at P0. We also observed that retinas of wild type animals had only 14% (P < 0.05) more ganglion cells compared to Notch3KO mice. Since this number is relatively small and Notch1 has been shown to contribute to ganglion cell fate specification, we suggested that Notch1 signaling may play a more significant role in RGC development than the Notch3 signaling cascade. Finally, our findings suggest that Notch1+ progenitors—since they heavily express both pro-ganglion cell (Atoh7) and pro-photoreceptor cell (Otx2) activators—can differentiate into either ganglion cells or photoreceptors.
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Affiliation(s)
- Galina Dvoriantchikova
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Isabel Perea-Martinez
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Steve Pappas
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Ariel Faye Barry
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Dagmara Danek
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Xenia Dvoriantchikova
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Daniel Pelaez
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Department of Biomedical Engineering, University of Miami, Coral Gables, Florida, United States of America
| | - Dmitry Ivanov
- Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, Florida, United States of America
- * E-mail:
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Wirth A, Cavallacci G, Genovesi-Ebert F. The advantages of an inverted retina. A physiological approach to a teleological question. Dev Ophthalmol 2015; 9:20-8. [PMID: 6098490 DOI: 10.1159/000409800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Hayakawa S, Takaku Y, Hwang JS, Horiguchi T, Suga H, Gehring W, Ikeo K, Gojobori T. Function and evolutionary origin of unicellular camera-type eye structure. PLoS One 2015; 10:e0118415. [PMID: 25734540 PMCID: PMC4348419 DOI: 10.1371/journal.pone.0118415] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 01/16/2015] [Indexed: 11/30/2022] Open
Abstract
The ocelloid is an extraordinary eyespot organelle found only in the dinoflagellate family Warnowiaceae. It contains retina- and lens-like structures called the retinal body and the hyalosome. The ocelloid has been an evolutionary enigma because of its remarkable resemblance to the multicellular camera-type eye. To determine if the ocelloid is functionally photoreceptive, we investigated the warnowiid dinoflagellate Erythropsidinium. Here, we show that the morphology of the retinal body changed depending on different illumination conditions and the hyalosome manifests the refractile nature. Identifying a rhodopsin gene fragment in Erythropsidinium ESTs that is expressed in the retinal body by in situ hybridization, we also show that ocelloids are actually light sensitive photoreceptors. The rhodopsin gene identified is most closely related to bacterial rhodopsins. Taken together, we suggest that the ocelloid is an intracellular camera-type eye, which might be originated from endosymbiotic origin.
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Affiliation(s)
- Shiho Hayakawa
- CIB-DDBJ, National Institute of Genetics, Mishima, Japan
| | | | | | - Takeo Horiguchi
- Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
| | - Hiroshi Suga
- Department of Cell Biology Biozentrum, University of Basel, Basel, Switzerland
| | - Walter Gehring
- Department of Cell Biology Biozentrum, University of Basel, Basel, Switzerland
| | - Kazuho Ikeo
- CIB-DDBJ, National Institute of Genetics, Mishima, Japan
| | - Takashi Gojobori
- CIB-DDBJ, National Institute of Genetics, Mishima, Japan
- Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan
- CBRC/BESE, KAUST, Thuwal, 23955-6900, Kingdom of Saudi Arabia
- * E-mail:
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43
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Santer RD. A colour opponent model that explains tsetse fly attraction to visual baits and can be used to investigate more efficacious bait materials. PLoS Negl Trop Dis 2014; 8:e3360. [PMID: 25473844 PMCID: PMC4256293 DOI: 10.1371/journal.pntd.0003360] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2014] [Accepted: 10/20/2014] [Indexed: 11/18/2022] Open
Abstract
Palpalis group tsetse flies are the major vectors of human African trypanosomiasis, and visually-attractive targets and traps are important tools for their control. Considerable efforts are underway to optimise these visual baits, and one factor that has been investigated is coloration. Analyses of the link between visual bait coloration and tsetse fly catches have used methods which poorly replicate sensory processing in the fly visual system, but doing so would allow the visual information driving tsetse attraction to these baits to be more fully understood, and the reflectance spectra of candidate visual baits to be more completely analysed. Following methods well established for other species, I reanalyse the numbers of tsetse flies caught at visual baits based upon the calculated photoreceptor excitations elicited by those baits. I do this for large sets of previously published data for Glossina fuscipes fuscipes (Lindh et al. (2012). PLoS Negl Trop Dis 6: e1661), G. palpalis palpalis (Green (1988). Bull Ent Res 78: 591), and G. pallidipes (Green and Flint (1986). Bull Ent Res 76: 409). Tsetse attraction to visual baits in these studies can be explained by a colour opponent mechanism to which the UV-blue photoreceptor R7y contributes positively, and both the green-yellow photoreceptor R8y, and the low-wavelength UV photoreceptor R7p, contribute negatively. A tool for calculating fly photoreceptor excitations is made available with this paper, and this will facilitate a complete and biologically authentic description of visual bait reflectance spectra that can be employed in the search for more efficacious visual baits, or the analysis of future studies of tsetse fly attraction.
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Affiliation(s)
- Roger D. Santer
- Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Aberystwyth, Ceredigion, United Kingdom
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Asaoka Y, Hata S, Namae M, Furutani-Seiki M, Nishina H. The Hippo pathway controls a switch between retinal progenitor cell proliferation and photoreceptor cell differentiation in zebrafish. PLoS One 2014; 9:e97365. [PMID: 24828882 PMCID: PMC4020862 DOI: 10.1371/journal.pone.0097365] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/17/2014] [Indexed: 12/31/2022] Open
Abstract
The precise regulation of numbers and types of neurons through control of cell cycle exit and terminal differentiation is an essential aspect of neurogenesis. The Hippo signaling pathway has recently been identified as playing a crucial role in promoting cell cycle exit and terminal differentiation in multiple types of stem cells, including in retinal progenitor cells. When Hippo signaling is activated, the core Mst1/2 kinases activate the Lats1/2 kinases, which in turn phosphorylate and inhibit the transcriptional cofactor Yap. During mouse retinogenesis, overexpression of Yap prolongs progenitor cell proliferation, whereas inhibition of Yap decreases this proliferation and promotes retinal cell differentiation. However, to date, it remains unknown how the Hippo pathway affects the differentiation of distinct neuronal cell types such as photoreceptor cells. In this study, we investigated whether Hippo signaling regulates retinogenesis during early zebrafish development. Knockdown of zebrafish mst2 induced early embryonic defects, including altered retinal pigmentation and morphogenesis. Similar abnormal retinal phenotypes were observed in zebrafish embryos injected with a constitutively active form of yap [(yap (5SA)]. Loss of Yap's TEAD-binding domain, two WW domains, or transcription activation domain attenuated the retinal abnormalities induced by yap (5SA), indicating that all of these domains contribute to normal retinal development. Remarkably, yap (5SA)-expressing zebrafish embryos displayed decreased expression of transcription factors such as otx5 and crx, which orchestrate photoreceptor cell differentiation by activating the expression of rhodopsin and other photoreceptor cell genes. Co-immunoprecipitation experiments revealed that Rx1 is a novel interacting partner of Yap that regulates photoreceptor cell differentiation. Our results suggest that Yap suppresses the differentiation of photoreceptor cells from retinal progenitor cells by repressing Rx1-mediated transactivation of photoreceptor cell genes during zebrafish retinogenesis.
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Affiliation(s)
- Yoichi Asaoka
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
- * E-mail: (YA); (HN)
| | - Shoji Hata
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Misako Namae
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Makoto Furutani-Seiki
- Centre for Regenerative Medicine, Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, United Kingdom
| | - Hiroshi Nishina
- Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
- * E-mail: (YA); (HN)
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Ke H, Tinsley MR, Steele A, Wang F, Showalter K. Link weight evolution in a network of coupled chemical oscillators. Phys Rev E Stat Nonlin Soft Matter Phys 2014; 89:052712. [PMID: 25353834 DOI: 10.1103/physreve.89.052712] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Indexed: 05/17/2023]
Abstract
Link weight evolution is studied in a network of coupled chemical oscillators. Oscillators are perturbed by adjustments in imposed light intensity based on excitatory or inhibitory links to other oscillators undergoing excitation. Experimental and modeling studies demonstrate that the network is capable of producing sustained coordinated activity. The individual nodes of the network exhibit incoherent firing events; however, a dominant frequency can be discerned within the collective signal by Fourier analysis. The introduction of spike-timing-dependent plasticity yields a network that evolves to a stable unimodal link weight distribution.
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Affiliation(s)
- Hua Ke
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045, USA
| | - Mark R Tinsley
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045, USA
| | - Aaron Steele
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045, USA
| | - Fang Wang
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045, USA
| | - Kenneth Showalter
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506-6045, USA
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Tochitsky I, Polosukhina A, Degtyar VE, Gallerani N, Smith CM, Friedman A, Van Gelder RN, Trauner D, Kaufer D, Kramer RH. Restoring visual function to blind mice with a photoswitch that exploits electrophysiological remodeling of retinal ganglion cells. Neuron 2014; 81:800-13. [PMID: 24559673 PMCID: PMC3933823 DOI: 10.1016/j.neuron.2014.01.003] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2013] [Indexed: 10/25/2022]
Abstract
Retinitis pigmentosa (RP) and age-related macular degeneration (AMD) are blinding diseases caused by the degeneration of rods and cones, leaving the remainder of the visual system unable to respond to light. Here, we report a chemical photoswitch named DENAQ that restores retinal responses to white light of intensity similar to ordinary daylight. A single intraocular injection of DENAQ photosensitizes the blind retina for days, restoring electrophysiological and behavioral responses with no toxicity. Experiments on mouse strains with functional, nonfunctional, or degenerated rods and cones show that DENAQ is effective only in retinas with degenerated photoreceptors. DENAQ confers light sensitivity on a hyperpolarization-activated inward current that is enhanced in degenerated retina, enabling optical control of retinal ganglion cell firing. The acceptable light sensitivity, favorable spectral sensitivity, and selective targeting to diseased tissue make DENAQ a prime drug candidate for vision restoration in patients with end-stage RP and AMD.
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Affiliation(s)
- Ivan Tochitsky
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Aleksandra Polosukhina
- Vision Science Graduate Group, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Vadim E Degtyar
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Nicholas Gallerani
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Caleb M Smith
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Aaron Friedman
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Russell N Van Gelder
- Departments of Ophthalmology, Pathology, and Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Dirk Trauner
- Department of Chemistry and Biochemistry, University of Munich, 81377 Munich, Germany
| | - Daniela Kaufer
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neurosciences Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Richard H Kramer
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Vision Science Graduate Group, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neurosciences Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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Abstract
Depending on the environment a young seedling encounters, the developmental program following seed germination could be skotomorphogenesis in the dark or photomorphogenesis in the light. Light signals are interpreted by a repertoire of photoreceptors followed by sophisticated gene expression networks, eventually resulting in developmental changes. The expression and functions of photoreceptors and key signaling molecules are highly coordinated and regulated at multiple levels of the central dogma in molecular biology. Light activates gene expression through the actions of positive transcriptional regulators and the relaxation of chromatin by histone acetylation. Small regulatory RNAs help attenuate the expression of light-responsive genes. Alternative splicing, protein phosphorylation/dephosphorylation, the formation of diverse transcriptional complexes, and selective protein degradation all contribute to proteome diversity and change the functions of individual proteins.
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Affiliation(s)
- Shu-Hsing Wu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan;
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Abstract
Adaptation is at the heart of sensation and nowhere is it more salient than in early visual processing. Light adaptation in photoreceptors is doubly dynamical: it depends upon the temporal structure of the input and it affects the temporal structure of the response. We introduce a non-linear dynamical adaptation model of photoreceptors. It is simple enough that it can be solved exactly and simulated with ease; analytical and numerical approaches combined provide both intuition on the behavior of dynamical adaptation and quantitative results to be compared with data. Yet the model is rich enough to capture intricate phenomenology. First, we show that it reproduces the known phenomenology of light response and short-term adaptation. Second, we present new recordings and demonstrate that the model reproduces cone response with great precision. Third, we derive a number of predictions on the response of photoreceptors to sophisticated stimuli such as periodic inputs, various forms of flickering inputs, and natural inputs. In particular, we demonstrate that photoreceptors undergo rapid adaptation of response gain and time scale, over ∼ 300[Formula: see text] ms-i. e., over the time scale of the response itself-and we confirm this prediction with data. For natural inputs, this fast adaptation can modulate the response gain more than tenfold and is hence physiologically relevant.
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Affiliation(s)
- Damon A. Clark
- Department of Physics, Ecole Normale Supérieure, Paris, France
| | | | - Markus Meister
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts, United States of America
| | - Rava Azeredo da Silveira
- Department of Physics, Ecole Normale Supérieure, Paris, France
- Laboratoire de Physique Statistique, Centre National de la Recherche Scientifique, Université Pierre et Marie Curie, Université Denis Diderot, Paris, France
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Veedin-Rajan VB, Fischer RM, Raible F, Tessmar-Raible K. Conditional and specific cell ablation in the marine annelid Platynereis dumerilii. PLoS One 2013; 8:e75811. [PMID: 24086637 PMCID: PMC3782428 DOI: 10.1371/journal.pone.0075811] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Accepted: 08/21/2013] [Indexed: 11/18/2022] Open
Abstract
The marine annelid Platynereis dumerilii has become a model system for evo-devo, neurobiology and marine biology. The functional assessment of its cell types, however, has so far been very limited. Here we report on the establishment of a generally applicable, cell type specific ablation technique to overcome this restriction. Using a transgenic strain expressing the bacterial enzyme nitroreductase (ntr) under the control of the worm’s r-opsin1 locus, we show that the demarcated photoreceptor cells can be specifically ablated by the addition of the prodrug metronidazole (mtz). TUNEL staining indicates that ntr expressing cells undergo apoptotic cell death. As we used a transgenic strain co-expressing ntr with enhanced green fluorescent protein (egfp) coding sequence, we were able to validate the ablation of photoreceptors not only in fixed tissue, using r-opsin1 riboprobes, but also by monitoring eGFP+ cells in live animals. The specificity of the ablation was demonstrated by the normal presence of the eye pigment cells, as well as of neuronal markers expressed in other cells of the brain, such as phc2, tyrosine hydroxylase and brn1/2/4. Additional analyses of the position of DAPI stained nuclei, the brain’s overall neuronal scaffold, as well as the positions and projections of serotonergic neurons further confirmed that mtz treatment did not induce general abnormalities in the worm’s brain. As the prodrug is administered by adding it to the water, targeted ablation of specific cell types can be achieved throughout the life of the animal. We show that ablation conditions need to be adjusted to the size of the worms, likely due to differences in the penetration of the prodrug, and establish ablation conditions for worms containing 10 to 55 segments. Our results establish mtz/ntr mediated conditional cell ablation as a powerful functional tool in Platynereis.
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Affiliation(s)
- Vinoth Babu Veedin-Rajan
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
- Research Platform “Marine Rhythms of Life,” Vienna, Austria
| | - Ruth M. Fischer
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
- Research Platform “Marine Rhythms of Life,” Vienna, Austria
| | - Florian Raible
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
- Research Platform “Marine Rhythms of Life,” Vienna, Austria
| | - Kristin Tessmar-Raible
- Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
- Research Platform “Marine Rhythms of Life,” Vienna, Austria
- * E-mail:
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50
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Huang M, Liu HX, Liao NF. [Correlation of visual spectral response with aging and its effect on color discrimination]. Guang Pu Xue Yu Guang Pu Fen Xi 2013; 33:1886-1891. [PMID: 24059195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The variation in normal observers' color perception and discrimination will occur with the aging effect. The authors carried out a psychophysical experiment with the method of binocular observational technique. Three observers at the age of 21, 32 and 58 were organized to match the 9 printed color samples on EIZO monitor with the repetition of 7 times. Groups of data for cross-media color matching with different age were established to investigate the response of photoreceptor cells. The results indicated that with the aging effect the chroma of the matched color will decrease obviously and the spectral response of the blue channel will decrease for blue and purple colors. The results validate the prediction of CIEPO06 model to some extent and provide some theoretical basis and experimental supports for the application of color reproduction and the color evaluation of the products related to age.
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Affiliation(s)
- Min Huang
- School of Printing and Packing Engineering, Beijing Institute of Graphics and Communication, Beijing 102600, China.
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