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Nigel Scrutton, Uzma Choudry, Derren Heyes, Samantha Hardman, Michiyo Sakuma, Igor Sazanovich, Joyce Woodhouse, Eugenio De La Mora, Martin Pederson, Michael Wulff, Martin Weik, Giorgio Schiro
Phytochromes are bilin-containing photoreceptors that are typically sensitive to the red / far-red region of the visible spectrum. Recently phytochromes from certain eukaryotic algae have become attractive targets for optogenetic applications because of their unique ability to respond to multiple wavelengths of light. Here, we have used a combination of time-resolved spectroscopy and structural approaches across picosecond to second timescales to map photochemical mechanisms and structural change in this atypical group of phytochromes...
March 15, 2018: Chembiochem: a European Journal of Chemical Biology
Javier Vicente-Tejedor, Miguel Marchena, Laura Ramírez, Diego García-Ayuso, Violeta Gómez-Vicente, Celia Sánchez-Ramos, Pedro de la Villa, Francisco Germain
Light causes damage to the retina (phototoxicity) and decreases photoreceptor responses to light. The most harmful component of visible light is the blue wavelength (400-500 nm). Different filters have been tested, but so far all of them allow passing a lot of this wavelength (70%). The aim of this work has been to prove that a filter that removes 94% of the blue component may protect the function and morphology of the retina significantly. Three experimental groups were designed. The first group was unexposed to light, the second one was exposed and the third one was exposed and protected by a blue-blocking filter...
2018: PloS One
Ji Yong Choi, Cheol Young Choi
This study was conducted to identify the possible effect of recombinant vertebrate ancient long (VAL) opsin as a non-visual "photoreceptor" in the deep brain of goldfish, Carassius auratus. In addition, we investigated the effects of green-wavelength light on the predictable reproductive function of VAL-opsin as a green-sensitive pigment in the deep brain. To determine this, we quantified changes in gonadotropin hormone (GTH) [GTHα, follicle stimulating hormone (FSH) and luteinizing hormone (LH)] and estrogen receptor (ER; ERα and ERβ) mRNA expression levels associated with goldfish reproduction as well as changes in plasma FSH, LH, and 17β-estradiol (E2 ) activities after injection of recombinant VAL-opsin protein in two concentrations (0...
March 14, 2018: Fish Physiology and Biochemistry
Alan D Marmorstein, Adiv A Johnson, Lori A Bachman, Cynthia Andrews-Pfannkoch, Travis Knudsen, Benjamin J Gilles, Matthew Hill, Jarel K Gandhi, Lihua Y Marmorstein, Jose S Pulido
Autosomal recessive bestrophinopathy (ARB) is caused by mutations in the gene BEST1 which encodes bestrophin 1 (Best1), an anion channel expressed in retinal pigment epithelial (RPE) cells. It has been hypothesized that ARB represents the human null phenotype for BEST1 and that this occurs due to nonsense mediated decay (NMD). To test this hypothesis, we generated induced pluripotent stem cells (iPSCs) from a patient with ARB and her parents. After differentiation to retinal pigment epithelial (iPSC-RPE) cells, both BEST1 mRNA and Best1 protein expression were compared to controls...
March 14, 2018: Scientific Reports
Hong Duan, Luis F de Navas, Fuqu Hu, Kailiang Sun, Yannis E Mavromatakis, Kayla Viets, Cyrus Zhou, Joshua Kavaler, Robert J Johnston, Andrew Tomlinson, Eric C Lai
Photoreceptors in the crystalline Drosophila eye are recruited by receptor tyrosine kinase (RTK)/Ras signaling, mediated by the Epidermal Growth Factor receptor (EGFR) and Sevenless receptor. Analyses of an allelic deletion series of the mir-279/996 locus, along with a panel of modified genomic rescue transgenes, show that normal Drosophila eye patterning depends on both miRNAs. Transcriptional reporter and activity sensor transgenes reveal expression and function of miR-279/996 in non-neural cells of the developing eye...
March 14, 2018: Development
Tilman Kottke, Aihua Xie, Delmar S Larsen, Wouter D Hoff
The first stage in biological signaling is based on changes in the functional state of a receptor protein triggered by interaction of the receptor with its ligand(s). The light-triggered nature of photoreceptors allows studies on the mechanism of such changes in receptor proteins using a wide range of biophysical methods and with superb time resolution. Here, we critically evaluate current understanding of proton and electron transfer in photosensory proteins and their involvement both in primary photochemistry and subsequent processes that lead to the formation of the signaling state...
March 14, 2018: Annual Review of Biophysics
Irina I Ignatova, Andrew S French, Roman V Frolov
Natural visual scenes are rarely random. Instead, intensity and wavelength change slowly in time and space over many regions of the scene, so that neighboring temporal and spatial visual inputs are more correlated, and contain less information than truly random signals. It has been suggested that sensory optimization to match these higher order correlations (HOC) occurs at the earliest visual stages, and that photoreceptors can process temporal natural signals more efficiently than random signals. We tested this early stage hypothesis by comparing the information content of Calliphora vicina photoreceptor responses to naturalistic inputs before and after removing HOC by randomizing phase...
March 14, 2018: Journal of Neurophysiology
Rachael S Allen, Adam M Hanif, Marissa A Gogniat, Brian C Prall, Raza Haider, Moe H Aung, Megan C Prunty, Lukas M Mees, Monica M Coulter, Cara T Motz, Jeffrey H Boatright, Machelle T Pardue
Diabetic retinopathy is a leading cause of vision loss. Treatment options for early retinopathy are sparse. Exercise protects dying photoreceptors in models of retinal degeneration, thereby preserving vision. We tested the protective effects of exercise on retinal and cognitive deficits in a Type 1 diabetes model and determined whether the TrkB pathway mediates this effect. This article is protected by copyright. All rights reserved.
March 14, 2018: European Journal of Neuroscience
Carl Arndt, Mathieu Costantini, Christophe Chiquet, Mickael Afriat, Sylvie Berthemy, Vivien Vasseur, Alain Ducasse, Martine Mauget-Faÿsse
PURPOSE: Pericentral visual field changes and disruption of the ellipsoid layer on spectral domain optical coherence tomography (SD-OCT) are the main features of antimalarial retinal toxicity. C-Scan OCT or "en face" enables a topographic frontal view of the changes observed within the different retinal layers in particular the ellipsoid layer. The aim of this prospective study was to compare multifocal ERG (mfERG) responses with the results of C-Scan OCT ("en face" OCT) in patients with abnormal visual field and to analyze relationships between the structural and functional abnormalities...
March 13, 2018: Documenta Ophthalmologica. Advances in Ophthalmology
Ji-Yeon Lee, Su-Ja Oh
The retinal degeneration resulting from elevated intraocular pressure was evaluated through functional and morphological analyses, for better understanding of the pathophysiology of glaucoma. Ocular hypertension was induced via unilateral episcleral venous cauterization in rats. Experimental time was set at 1 and 3 days, and 1, 2, 4, and 8 weeks post-operation. Retinal function was analyzed using electroretinography. For morphological analysis, retinal tissues were processed for immunochemistry by using antibodies against the calcium-sensing receptor and calcium-binding proteins...
February 2018: Experimental Neurobiology
George Inana, Christopher Murat, Weijun An, Xiang Yao, Ian R Harris, Jing Cao
BACKGROUND: Age-related macular degeneration (AMD) is a leading cause of blindness among the elderly characterized by retinal pigment epithelium (RPE) degeneration with accumulation of abnormal intracellular deposits (lipofuscin) and photoreceptor death. RPE is vital for the retina and integrity of photoreceptors through its phagocytic function which is closely linked to formation of lipofuscin through daily phagocytosis of discarded photoreceptor outer segments (POS). Although phagocytosis has been implicated in AMD, it has not been directly shown to be altered in AMD...
March 13, 2018: Journal of Translational Medicine
Uwe Wolfrum, Kerstin Nagel-Wolfrum
The human Usher syndrome (USH) is a complex, rare disease manifesting in its most common form of inherited deaf-blindness. Due to the heterogeneous manifestation of the clinical symptoms, three clinical types (USH1-3) are distinguished according to the severity of the disease pattern. For a correct diagnosis, in addition to the auditory tests in early newborn screening, ophthalmological examinations and molecular genetic analysis are important. Ten known USH genes encode proteins, which are from heterogeneous protein families, interact in functional protein networks...
March 2018: Klinische Monatsblätter Für Augenheilkunde
Christina Gerth-Kahlert, Samuel Koller
Ciliopathies are disorders caused by ciliary dysfunction and can affect an organ system or tissues. Isolated or syndromic retinal dystrophies are the most common ocular manifestation of ciliopathies. The photoreceptor connecting cilium plays a leading role in these ciliopathy-related retinal dystrophies. Dysfunctional photoreceptor cilia cause the most severe type of retinal dystrophy: Leber's congenital amaurosis (LCA). The most common syndromic ciliopathies with an ocular manifestation are Bardet-Biedl syndrome (BBS) and Usher syndrome...
March 2018: Klinische Monatsblätter Für Augenheilkunde
Nilisha Fernando, Riccardo Natoli, Tanja Racic, Yvette Wooff, Jan Provis, Krisztina Valter
The complement system is highly implicated in both the prevalence and progression of Age-Related Macular Degeneration (AMD). Complement system inhibitors therefore have potential therapeutic value in managing excessive activation of the complement pathways in retinal degenerations. The vaccinia virus complement control protein (VCP) has been shown to be effective as a complement inhibitor in neuroinflammatory models including traumatic brain injury and spinal cord injury. We aimed to investigate the potential of VCP as a therapeutic molecule for retinal degenerations...
2018: PloS One
Alexandra Garancher, Charles Y Lin, Morgane Morabito, Wilfrid Richer, Nathalie Rocques, Magalie Larcher, Laure Bihannic, Kyle Smith, Catherine Miquel, Sophie Leboucher, Nirmitha I Herath, Fanny Dupuy, Pascale Varlet, Christine Haberler, Christine Walczak, Nadine El Tayara, Andreas Volk, Stéphanie Puget, François Doz, Olivier Delattre, Sabine Druillennec, Olivier Ayrault, Robert J Wechsler-Reya, Alain Eychène, Franck Bourdeaut, Paul A Northcott, Celio Pouponnot
Cancer cells often express differentiation programs unrelated to their tissue of origin, although the contribution of these aberrant phenotypes to malignancy is poorly understood. An aggressive subgroup of medulloblastoma, a malignant pediatric brain tumor of the cerebellum, expresses a photoreceptor differentiation program normally expressed in the retina. We establish that two photoreceptor-specific transcription factors, NRL and CRX, are master regulators of this program and are required for tumor maintenance in this subgroup...
March 12, 2018: Cancer Cell
Anthony M Rossi, Vilaiwan M Fernandes
Various regions of the developing brain coordinate their construction so that the correct types and numbers of cells are generated to build a functional network. We previously discovered that wrapping glia in the Drosophila visual system are essential for coordinating retinal and lamina development. We showed that wrapping glia, which ensheath photoreceptor axons, respond to an epidermal growth factor cue from photoreceptors by secreting insulins. Wrapping glial insulins activate the mitogen-activated protein kinase (MAPK) pathway downstream of insulin receptor in lamina precursors to induce neuronal differentiation...
2018: Journal of Experimental Neuroscience
Eleonora Vighi, Dragana Trifunović, Patricia Veiga-Crespo, Andreas Rentsch, Dorit Hoffmann, Ayse Sahaboglu, Torsten Strasser, Manoj Kulkarni, Evelina Bertolotti, Angelique van den Heuvel, Tobias Peters, Arie Reijerkerk, Thomas Euler, Marius Ueffing, Frank Schwede, Hans-Gottfried Genieser, Pieter Gaillard, Valeria Marigo, Per Ekström, François Paquet-Durand
Inherited retinal degeneration (RD) is a devastating and currently untreatable neurodegenerative condition that leads to loss of photoreceptor cells and blindness. The vast genetic heterogeneity of RD, the lack of "druggable" targets, and the access-limiting blood-retinal barrier (BRB) present major hurdles toward effective therapy development. Here, we address these challenges ( i ) by targeting cGMP (cyclic guanosine- 3',5'-monophosphate) signaling, a disease driver common to different types of RD, and ( ii ) by combining inhibitory cGMP analogs with a nanosized liposomal drug delivery system designed to facilitate transport across the BRB...
March 12, 2018: Proceedings of the National Academy of Sciences of the United States of America
Victoria Moriconi, Melanie Binkert, María Cecilia Costigliolo Rojas, Romina Sellaro, Roman Ulm, Jorge Jose Casal
Sunflecks, transient patches of light that penetrate through gaps in the canopy and transiently interrupt shade, are eco-physiologically and agriculturally important sources of energy for carbon gain, but our molecular understanding of how plant organs perceive and respond to sunflecks remains limited. The UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8) is a recent addition to the list of plant photo-sensory receptors and, we have made considerable advances in our understanding of the physiology and molecular mechanisms of action of UVR8 and its signalling pathway...
March 12, 2018: Plant Physiology
Ebru N Cetin, Selda Sayin Kutlu, Osman Parca, Murat Kutlu, Gökhan Pekel
PURPOSE: To evaluate choroidal, macular, peripapillary retinal nerve fiber layer (RNFL) thicknesses and retinal vascular caliber alterations in HIV-1-infected patients without opportunistic infections. METHODS: This cross-sectional study included 45 HIV-1-infected patients and 47 healthy subjects. Spectral domain optical coherence tomography was used for assessment of choroidal, macular, peripapillary RNFL thicknesses and retinal vascular caliber alterations. RESULTS: The mean CD4 count was 426 ± 226 cells per milliliter and the mean HIV-1 RNA level was 1...
March 8, 2018: Retina
Bo-Mi Song, Chi-Hon Lee
Many visual animals exploit spectral information for seeking food and mates, for identifying preys and predators, and for navigation. Animals use chromatic information in two ways. "True color vision," the ability to discriminate visual stimuli on the basis of their spectral content independent of brightness, is thought to play an important role in object identification. In contrast, "wavelength-specific behavior," which is strongly dependent on brightness, often associates with foraging, navigation, and other species-specific needs...
2018: Frontiers in Neural Circuits
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