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https://www.readbyqxmd.com/read/28221832/what-explains-patterns-of-diversification-and-richness-among-animal-phyla
#1
Tereza Jezkova, John J Wiens
Animal phyla vary dramatically in species richness (from one species to >1.2 million), but the causes of this variation remain largely unknown. Animals have also evolved striking variation in morphology and ecology, including sessile marine taxa lacking heads, eyes, limbs, and complex organs (e.g., sponges), parasitic worms (e.g., nematodes, platyhelminths), and taxa with eyes, skeletons, limbs, and complex organs that dominate terrestrial ecosystems (arthropods, chordates). Relating this remarkable variation in traits to the diversification and richness of animal phyla is a fundamental yet unresolved problem in biology...
March 2017: American Naturalist
https://www.readbyqxmd.com/read/28220575/generation-of-storable-retinal-organoids-and-retinal-pigmented-epithelium-from-adherent-human-ips-cells-in-xeno-free-and-feeder-free-conditions
#2
Sacha Reichman, Amélie Slembrouck, Giuliana Gagliardi, Antoine Chaffiol, Angélique Terray, Céline Nanteau, Anais Potey, Morgane Belle, Oriane Rabesandratana, Jens Duebel, Gael Orieux, Emeline F Nandrot, José-Alain Sahel, Olivier Goureau
Human induced pluripotent stem cells (hiPSCs) are potentially useful in regenerative therapies for retinal disease. For medical applications, therapeutic retinal cells, such as retinal pigmented epithelial (RPE) cells or photoreceptor precursors, must be generated under completely defined conditions. To this purpose, we have developed a two-step xeno-free/feeder-free (XF/FF) culture system to efficiently differentiate hiPSCs into retinal cells. This simple method, relies only on adherent hiPSCs cultured in chemically defined media, bypassing embryoid body formation...
February 20, 2017: Stem Cells
https://www.readbyqxmd.com/read/28219732/all-trans-retinal-levels-and-formation-of-lipofuscin-precursors-after-bleaching-in-rod-photoreceptors-from-wild-type-and-abca4-mice
#3
Leopold Adler, Chunhe Chen, Yiannis Koutalos
The accumulation of lipofuscin in the cells of the retinal pigment epithelium (RPE) is thought to play an important role in the development and progression of degenerative diseases of the retina. The bulk of RPE lipofuscin originates in reactions of the rhodopsin chromophore, retinal, with components of the photoreceptor outer segment. The 11-cis retinal isomer is generated in the RPE and supplied to rod photoreceptor outer segments where it is incorporated as the chromophore of rhodopsin. It is photoisomerized during light detection to all-trans and subsequently released by photoactivated rhodopsin as all-trans retinal, which is removed through reduction to all-trans retinol in a reaction requiring metabolic input in the form of NADPH...
February 17, 2017: Experimental Eye Research
https://www.readbyqxmd.com/read/28217951/cytotoxic-effect-of-zinc-oxide-nanoparticles-on-murine-photoreceptor-cells-via-potassium-channel-block-and-na-k-atpase-inhibition
#4
Chao Chen, Wenjuan Bu, Hongyan Ding, Qin Li, Dabo Wang, Hongsheng Bi, Dadong Guo
OBJECTIVE: Zinc oxide (ZnO) nanoparticles can exhibit toxicity towards organisms and oxidative stress is often hypothesized to be one of the most important factors. Nevertheless, the detailed mechanism of toxicity-induced by ZnO nanoparticles has not been completely addressed. The present study aimed to investigate the toxic effects of ZnO nanoparticles on the expression and activity of Na(+) /K(+) -ATPase and on potassium channel block. MATERIALS AND METHODS: In the present study, we explored the cytotoxic effect of ZnO nanoparticles on murine photoreceptor cells using lactate dehydrogenase (LDH) release assay, reactive oxygen species (ROS) determination, mitochondrial membrane potential (Δφm) measurement, delayed rectifier potassium current recordings and Na(+) /K(+) -ATPase expression and activity monitoring...
February 19, 2017: Cell Proliferation
https://www.readbyqxmd.com/read/28216676/fractalkine-cx3cr1-signaling-is-critical-for-progesterone-mediated-neuroprotection-in-the-retina
#5
Sarah L Roche, Alice C Wyse-Jackson, Ana M Ruiz-Lopez, Ashleigh M Byrne, Thomas G Cotter
Retinitis pigmentosa (RP) encompasses a group of retinal diseases resulting in photoreceptor loss and blindness. We have previously shown in the rd10 mouse model of RP, that rd10 microglia drive degeneration of viable neurons. Norgestrel, a progesterone analogue, primes viable neurons against potential microglial damage. In the current study we wished to investigate this neuroprotective effect further. We were particularly interested in the role of fractalkine-CX3CR1 signaling, previously shown to mediate photoreceptor-microglia crosstalk and promote survival in the rd10 retina...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28216641/targeted-rp9-ablation-and-mutagenesis-in-mouse-photoreceptor-cells-by-crispr-cas9
#6
Ji-Neng Lv, Gao-Hui Zhou, Xuejiao Chen, Hui Chen, Kun-Chao Wu, Lue Xiang, Xin-Lan Lei, Xiao Zhang, Rong-Han Wu, Zi-Bing Jin
Precursor messenger RNA (Pre-mRNA) splicing is an essential biological process in eukaryotic cells. Genetic mutations in many spliceosome genes confer human eye diseases. Mutations in the pre-mRNA splicing factor, RP9 (also known as PAP1), predispose autosomal dominant retinitis pigmentosa (adRP) with an early onset and severe vision loss. However, underlying molecular mechanisms of the RP9 mutation causing photoreceptor degeneration remains fully unknown. Here, we utilize the CRISPR/Cas9 system to generate both the Rp9 gene knockout (KO) and point mutation knock in (KI) (Rp9, c...
February 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28216039/molecular-cloning-and-function-analysis-of-clcry1a-and-clcry1b-two-genes-in-chrysanthemum-lavandulifolium-that-play-vital-roles-in-promoting-floral-transition
#7
Liwen Yang, Jianxin Fu, Shuai Qi, Yan Hong, He Huang, Silan Dai
Cryptochrome (CRY), a vital photoreceptor which mediates light signals, controls photomorphogenesis in higher plants. However, the function of CRY in mediating light to regulate growth and development of ornamental plants is still unclear. In this study, we identified two CRY1 homologous genes, ClCRY1a and ClCRY1b, from Chrysanthemum lavandulifolium, a diploid wild chrysanthemum species. Expression analysis demonstrated that these two ClCRY1 genes showed the highest expression levels in seedlings leaves that were transferred to short day (SD) conditions for eight days...
February 16, 2017: Gene
https://www.readbyqxmd.com/read/28215987/accelerated-retinal-aging-in-pacap-knock-out-mice
#8
Andrea Kovács-Valasek, Krisztina Szabadfi, Viktória Dénes, Bálint Szalontai, Andrea Tamás, Péter Kiss, Aliz Szabó, Gyorgy Setalo, Dóra Reglődi, Robert Gábriel
Pituitary adenylate cyclase activating polypeptide (PACAP) is a neurotrophic and neuroprotective peptide. PACAP and its receptors are widely distributed in the retina. A number of reports provided evidence that PACAP is neuroprotective in retinal degenerations. The current study compared retina cell type-specific differences in young (3-4months) and aged adults (14-16months), of wild-type (WT) mice and knock-out (KO) mice lacking endogenous PACAP production during the course of aging. Histological, immunocytochemical and Western blot examinations were performed...
February 13, 2017: Neuroscience
https://www.readbyqxmd.com/read/28215352/photoreceptors-in-the-dark-a-functional-white-collar-like-complex-and-other-putative-light-sensing-components-encoded-by-the-genome-of-the-subterranean-fungus-tuber-melanosporum
#9
Raffaele Gerace, Barbara Montanini, Marco Proietto, Elisabetta Levati, Cristina De Luca, Andrea Brenna, Patrizia Filetici, Annegret Kohler, Simone Ottonello, Paola Ballario
Light is perceived and transduced by fungi, where it modulates processes as diverse as growth and morphogenesis, sexual development and secondary metabolism. A special case in point is that of fungi with a subterranean, light-shielded habitat such as Tuber spp. Using as reference the genome sequence of the black truffle Tuber melanosporum, we used bioinformatic prediction tools and expression data to gain insight on the photoreceptor systems of this hypogeous ectomycorrhizal fungus. These include a chromophore-less opsin, a putative red-light-sensing phytochrome not expressed at detectable levels in any of the examined lifecycle stages, and a nearly canonical two-component (WC-1/WC-2) photoreceptor system similar to the Neurospora white collar complex (WCC)...
March 2017: Fungal Biology
https://www.readbyqxmd.com/read/28213397/regional-differences-in-the-preferred-e-vector-orientation-of-honeybee-ocellar-photoreceptors
#10
Yuri Ogawa, Willi Ribi, Jochen Zeil, Jan M Hemmi
In addition to compound eyes, honeybees (Apis mellifera) possess three single lens eyes called ocelli located on the top of the head. Ocelli are involved in head-attitude control and in some insects have been shown to provide celestial compass information. Anatomical and early electrophysiological studies have suggested that UV and blue-green photoreceptors in ocelli are polarization sensitive. However, their retinal distribution and receptor characteristics have not been documented. Here, we used intracellular electrophysiology to determine the relationship between the spectral and polarization sensitivity of photoreceptors and their position within the visual field of the ocelli...
February 17, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28212877/defining-outcomes-for-clinical-trials-of-leber-congenital-amaurosis-caused-by-gucy2d-mutations
#11
Samuel G Jacobson, Artur V Cideciyan, Alexander Sumaroka, Alejandro J Roman, Jason Charng, Monica Lu, Shreyasi Choudhury, Sharon B Schwartz, Elise Heon, Gerald A Fishman, Shannon E Boye
PURPOSE: To determine outcome measures for a clinical trial of Leber congenital amaurosis (LCA) associated with mutations in the GUCY2D gene. DESIGN: Retrospective observational case series. METHODS: 28 patients with GUCY2D-LCA (ages 2-59) were studied clinically and with chromatic full-field sensitivity testing (FST), optical coherence tomography (OCT), pupillometry, and the NEI Visual Function Questionnaire. RESULTS: FST permitted quantitation of cone and rod sensitivity in these patients with severe visual impairment...
February 14, 2017: American Journal of Ophthalmology
https://www.readbyqxmd.com/read/28212859/docosahexaenoic-acid-phospholipid-differentially-modulates-the-conformation-of-g90v-and-n55k-rhodopsin-mutants-associated-with-retinitis-pigmentosa
#12
Xiaoyun Dong, María Guadalupe Herrera-Hernández, Eva Ramon, Pere Garriga
Rhodopsin is the visual photoreceptor of the retinal rod cells that mediates dim light vision and a prototypical member of the G protein-coupled receptor superfamily. The structural stability and functional performance of rhodopsin are modulated by membrane lipids. Docosahexaenoic acid has been shown to interact with native rhodopsin but no direct evidence has been established on the effect of such lipid on the stability and regeneration of rhodopsin mutants associated with retinal diseases. The stability and regeneration of two thermosensitive mutants G90V and N55K, associated with the retinal degenerative disease retinitis pigmentosa, have been analyzed in docosohexaenoic phospholipid (1,2-didocosa-hexaenoyl-sn-glycero-3-phosphocholine; DDHA-PC) liposomes...
February 14, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28212399/instrument-design-and-protocol-for-the-study-of-light-controlled-processes-in-aquatic-organisms-and-its-application-to-examine-the-effect-of-infrared-light-on-zebrafish
#13
Marcus P S Dekens, Nicholas S Foulkes, Kristin Tessmar-Raible
The acquisition of reliable data strongly depends on experimental design. When studying the effects of light on processes such as behaviour and physiology it is crucial to maintain all environmental conditions constant apart from the one under study. Furthermore, the precise values of the environmental factors applied during the experiment should be known. Although seemingly obvious, these conditions are often not met when the effects of light are being studied. Here, we document and discuss the wavelengths and light intensities of natural and artificial light sources...
2017: PloS One
https://www.readbyqxmd.com/read/28210796/optogenetic-switches-for-light-controlled-gene-expression-in-yeast
#14
REVIEW
Francisco Salinas, Vicente Rojas, Verónica Delgado, Eduardo Agosin, Luis F Larrondo
Light is increasingly recognized as an efficient means of controlling diverse biological processes with high spatiotemporal resolution. Optogenetic switches are molecular devices for regulating light-controlled gene expression, protein localization, signal transduction and protein-protein interactions. Such molecular components have been mainly developed through the use of photoreceptors, which upon light stimulation undergo conformational changes passing to an active state. The current repertoires of optogenetic switches include red, blue and UV-B light photoreceptors and have been implemented in a broad spectrum of biological platforms...
February 16, 2017: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/28210739/retinal-oxidative-stress-at-the-onset-of-diabetes-determined-by-synchrotron-ftir-widefield-imaging-towards-diabetes-pathogenesis
#15
Ebrahim Aboualizadeh, Mahsa Ranji, Christine M Sorenson, Reyhaneh Sepehr, Nader Sheibani, Carol J Hirschmugl
Diabetic retinopathy is a microvascular complication of diabetes that can lead to blindness. In the present study, we aimed to determine the nature of diabetes-induced, highly localized biochemical changes in the neuroretina at the onset of diabetes. High-resolution synchrotron Fourier transform infrared (s-FTIR) wide field microscopy coupled with multivariate analysis (PCA-LDA) was employed to identify biomarkers of diabetic retinopathy with spatial resolution at the cellular level. We compared the retinal tissue prepared from 6-week-old Ins2(Akita/+) heterozygous (Akita/+, N = 6; a model of diabetes) male mice with the wild-type (control, N = 6) mice...
February 17, 2017: Analyst
https://www.readbyqxmd.com/read/28210098/mertk-gene-expression-and-photoreceptor-outer-segment-phagocytosis-by-cultured-rat-bone-marrow-mesenchymal-stem-cells
#16
Rong-Mei Peng, Jing Hong, Ying Jin, Yu-Zhao Sun, Yi-Qian Sun, Pei Zhang
BACKGROUND: Bone marrow mesenchymal stem cells (BM-MSCs) are multipotential stem cells that have been used for a broad spectrum of indications. Several investigations have used BM-MSCs to promote photoreceptor survival and suggested that BM-MSCs are a potential source of cell replacement therapy for some forms of retinal degeneration. PURPOSE: To investigate the expression of the MER proto-oncogene, tyrosine kinase (Mertk), involved in the disruption of RPE phagocytosis and the onset of autosomal recessive retinitis pigmentosa in rat BM-MSCs and to compare phagocytosis of the photoreceptor outer segment (POS) by BM-MSCs and RPE cells in vitro...
2017: Molecular Vision
https://www.readbyqxmd.com/read/28209709/pathogenic-mutations-in-retinitis-pigmentosa-2-predominantly-result-in-loss-of-rp2-protein-stability-in-human-and-zebrafish
#17
Fei Liu, Yayun Qin, Shanshan Yu, Dinesh C Soares, Lifang Yang, Jun Weng, Chang Li, Meng Gao, Zhaojing Lu, Xuebin Hu, Xiliang Liu, Tao Jiang, Jing Y Liu, Xinhua Shu, Zhaohui Tang, Mugen Liu
Mutations in retinitis pigmentosa 2 (RP2) account for 10-20% of X-linked retinitis pigmentosa (RP) cases. The encoded RP2 protein is implicated in ciliary trafficking of myristoylated and prenylated proteins in photoreceptor cells. To date, over 70 mutations in RP2 have been identified. How these mutations disrupt the function of RP2 is not fully understood. Here, we report a novel in-frame 12-bp deletion (c.357_368del, p.Pro120_Gly123del) in zebrafish rp2 The mutant zebrafish shows reduced rod phototransduction proteins and progressive retinal degeneration...
February 16, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28209509/the-raptor-visual-system-an-update
#18
J González-Martín-Moro, J L Hernández-Verdejo, A Clement-Corral
OBJECTIVE: Diurnal birds of prey (raptors) are considered the group of animals with highest visual acuity (VA). The purpose of this work is to review all the information recently published about the visual system of this group of animals. MATERIAL AND METHODS: A bibliographic search was performed in PubMed. The algorithm used was (raptor OR falcon OR kestrel OR hawk OR eagle) AND (vision OR «visual acuity» OR eye OR macula OR retina OR fovea OR «nictitating membrane» OR «chromatic vision» OR ultraviolet)...
February 13, 2017: Archivos de la Sociedad Española de Oftalmología
https://www.readbyqxmd.com/read/28209381/an-easy-fast-and-low-tech-equipment-requiring-alternative-method-to-optimize-immunolabelling-conditions-for-pre-embedding-immunogold-electron-microscopy-and-to-correlate-light-and-electron-microscopical-immunogold-labelling-results
#19
Shweta Suiwal, Gabriele Kiefer, Frank Schmitz, Karin Schwarz
Correlating light microscopic immunolabelling results with electron microscopic data is of great interest in many fields of biomedical research but typically requires very specialized, expensive equipment and complex procedures which are not available in most labs. In this technical study, we describe an easy and "low-tech"-equipment-requiring pre-embedding immunolabelling approach that allows correlation of light microscopical immunolabelling results with electron microscopic (EM) data as demonstrated by the example of immunolabelled synaptic ribbons from retinal rod photoreceptor synapses...
February 13, 2017: Journal of Immunological Methods
https://www.readbyqxmd.com/read/28208212/the-function-of-the-ocelloid-and-piston-in-the-dinoflagellate-erythropsidinium-gymnodiniales-dinophyceae
#20
Fernando Gómez
The marine dinoflagellate Erythropsidinium possesses an ocelloid, the most elaborate photoreceptor organelle known in a unicellular organism, and a piston, a fast contractile appendage unknown in any other organism. The ocelloid is able to rotate, often before the cell swims. The ocelloid contains lenses that function to concentrate light. The flagellar propulsion is atrophied, and the piston is responsible for locomotion through successive extensions and contractions. During the 'locomotion mode', the contraction is ~4 times faster than the extension...
February 16, 2017: Journal of Phycology
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