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Sample records for avian cone photoreceptors

  1. Optics of cone photoreceptors in the chicken (Gallus gallus domesticus)

    OpenAIRE

    Wilby, David; Toomey, Matthew B.; Olsson, Peter; Frederiksen, Rikard; Cornwall, M. Carter; Oulton, Ruth; Kelber, Almut; Joseph C Corbo; Roberts, Nicholas W.

    2015-01-01

    Vision is the primary sensory modality of birds, and its importance is evident in the sophistication of their visual systems. Coloured oil droplets in the cone photoreceptors represent an adaptation in the avian retina, acting as long-pass colour filters. However, we currently lack understanding of how the optical properties and morphology of component structures (e.g. oil droplet, mitochondrial ellipsoid and outer segment) of the cone photoreceptor influence the transmission of light into th...

  2. Integrity of the cone photoreceptor mosaic in oligocone trichromacy

    DEFF Research Database (Denmark)

    Michaelides, Michel; Rha, Jungtae; Dees, Elise W; Baraas, Rigmor C; Wagner-Schuman, Melissa L; Mollon, John D; Dubis, Adam M; Andersen, Mette K G; Rosenberg, Thomas; Larsen, Michael; Moore, Anthony T; Carroll, Joseph

    2011-01-01

    Oligocone trichromacy (OT) is an unusual cone dysfunction syndrome characterized by reduced visual acuity, mild photophobia, reduced amplitude of the cone electroretinogram with normal rod responses, normal fundus appearance, and normal or near-normal color vision. It has been proposed that these...... patients have a reduced number of normal functioning cones (oligocone). This paper has sought to evaluate the integrity of the cone photoreceptor mosaic in four patients previously described as having OT....

  3. Avian photoreceptor patterns represent a disordered hyperuniform solution to a multiscale packing problem.

    Science.gov (United States)

    Jiao, Yang; Lau, Timothy; Hatzikirou, Haralampos; Meyer-Hermann, Michael; Joseph C Corbo; Torquato, Salvatore

    2014-02-01

    Optimal spatial sampling of light rigorously requires that identical photoreceptors be arranged in perfectly regular arrays in two dimensions. Examples of such perfect arrays in nature include the compound eyes of insects and the nearly crystalline photoreceptor patterns of some fish and reptiles. Birds are highly visual animals with five different cone photoreceptor subtypes, yet their photoreceptor patterns are not perfectly regular. By analyzing the chicken cone photoreceptor system consisting of five different cell types using a variety of sensitive microstructural descriptors, we find that the disordered photoreceptor patterns are "hyperuniform" (exhibiting vanishing infinite-wavelength density fluctuations), a property that had heretofore been identified in a unique subset of physical systems, but had never been observed in any living organism. Remarkably, the patterns of both the total population and the individual cell types are simultaneously hyperuniform. We term such patterns "multihyperuniform" because multiple distinct subsets of the overall point pattern are themselves hyperuniform. We have devised a unique multiscale cell packing model in two dimensions that suggests that photoreceptor types interact with both short- and long-ranged repulsive forces and that the resultant competition between the types gives rise to the aforementioned singular spatial features characterizing the system, including multihyperuniformity. These findings suggest that a disordered hyperuniform pattern may represent the most uniform sampling arrangement attainable in the avian system, given intrinsic packing constraints within the photoreceptor epithelium. In addition, they show how fundamental physical constraints can change the course of a biological optimization process. Our results suggest that multihyperuniform disordered structures have implications for the design of materials with novel physical properties and therefore may represent a fruitful area for future

  4. Avian photoreceptor patterns represent a disordered hyperuniform solution to a multiscale packing problem

    Science.gov (United States)

    Jiao, Yang; Lau, Timothy; Hatzikirou, Haralampos; Meyer-Hermann, Michael; Corbo, Joseph C.; Torquato, Salvatore

    2014-02-01

    Optimal spatial sampling of light rigorously requires that identical photoreceptors be arranged in perfectly regular arrays in two dimensions. Examples of such perfect arrays in nature include the compound eyes of insects and the nearly crystalline photoreceptor patterns of some fish and reptiles. Birds are highly visual animals with five different cone photoreceptor subtypes, yet their photoreceptor patterns are not perfectly regular. By analyzing the chicken cone photoreceptor system consisting of five different cell types using a variety of sensitive microstructural descriptors, we find that the disordered photoreceptor patterns are "hyperuniform" (exhibiting vanishing infinite-wavelength density fluctuations), a property that had heretofore been identified in a unique subset of physical systems, but had never been observed in any living organism. Remarkably, the patterns of both the total population and the individual cell types are simultaneously hyperuniform. We term such patterns "multihyperuniform" because multiple distinct subsets of the overall point pattern are themselves hyperuniform. We have devised a unique multiscale cell packing model in two dimensions that suggests that photoreceptor types interact with both short- and long-ranged repulsive forces and that the resultant competition between the types gives rise to the aforementioned singular spatial features characterizing the system, including multihyperuniformity. These findings suggest that a disordered hyperuniform pattern may represent the most uniform sampling arrangement attainable in the avian system, given intrinsic packing constraints within the photoreceptor epithelium. In addition, they show how fundamental physical constraints can change the course of a biological optimization process. Our results suggest that multihyperuniform disordered structures have implications for the design of materials with novel physical properties and therefore may represent a fruitful area for future

  5. Characterizing the Human Cone Photoreceptor Mosaic via Dynamic Photopigment Densitometry

    Science.gov (United States)

    Sabesan, Ramkumar; Hofer, Heidi; Roorda, Austin

    2015-01-01

    Densitometry is a powerful tool for the biophysical assessment of the retina. Until recently, this was restricted to bulk spatial scales in living humans. The application of adaptive optics (AO) to the conventional fundus camera and scanning laser ophthalmoscope (SLO) has begun to translate these studies to cellular scales. Here, we employ an AOSLO to perform dynamic photopigment densitometry in order to characterize the optical properties and spectral types of the human cone photoreceptor mosaic. Cone-resolved estimates of optical density and photosensitivity agree well with bulk estimates, although show smaller variability than previously reported. Photopigment kinetics of individual cones derived from their selective bleaching allowed efficient mapping of cone sub-types in human retina. Estimated uncertainty in identifying a cone as long vs middle wavelength was less than 5%, and the total time taken per subject ranged from 3–9 hours. Short wavelength cones were delineated in every subject with high fidelity. The lack of a third cone-type was confirmed in a protanopic subject. In one color normal subject, cone assignments showed 91% correspondence against a previously reported cone-typing method from more than a decade ago. Combined with cone-targeted stimulation, this brings us closer in studying the visual percept arising from a specific cone type and its implication for color vision circuitry. PMID:26660894

  6. Developmental dynamics of cone photoreceptors in the eel

    Directory of Open Access Journals (Sweden)

    Semo Ma'ayan

    2009-12-01

    Full Text Available Abstract Background Many fish alter their expressed visual pigments during development. The number of retinal opsins expressed and their type is normally related to the environment in which they live. Eels are known to change the expression of their rod opsins as they mature, but might they also change the expression of their cone opsins? Results The Rh2 and Sws2 opsin sequences from the European Eel were isolated, sequenced and expressed in vitro for an accurate measurement of their λmax values. In situ hybridisation revealed that glass eels express only rh2 opsin in their cone photoreceptors, while larger yellow eels continue to express rh2 opsin in the majority of their cones, but also have Conclusions Larger yellow and silver European eels express two different cone opsins, rh2 and sws2. This work demonstrates that only the Rh2 cone opsin is present in younger fish (smaller yellow and glass, the sws2 opsin being expressed additionally only by older fish and only in

  7. Evolutionary transformation of rod photoreceptors in the all-cone retina of a diurnal garter snake

    OpenAIRE

    Ryan K Schott; Müller, Johannes; Yang, Clement G. Y.; Bhattacharyya, Nihar; Chan, Natalie; Xu, Mengshu; Morrow, James M.; Ghenu, Ana-Hermina; Loew, Ellis R.; Tropepe, Vincent; Chang, Belinda S W

    2015-01-01

    This study provides compelling evidence that the previously reported all-cone retina of a diurnal garter snake in fact contains a population of rod photoreceptors with the appearance, and presumably function, of cones. Our results suggest that the evolution of all-cone retinas occurred not through loss of rods but rather via the evolutionary transmutation of ancestral rods into more “cone-like” photoreceptors, to regain functionality that was lost during the early, possibly fossorial, origin ...

  8. Cone opsin determines the time course of cone photoreceptor degeneration in Leber congenital amaurosis.

    Science.gov (United States)

    Zhang, Tao; Zhang, Ning; Baehr, Wolfgang; Fu, Yingbin

    2011-05-24

    Mutations in RPE65 or lecithin-retinol acyltransferase (LRAT) disrupt 11-cis-retinal recycling and cause Leber congenital amaurosis (LCA), the most severe retinal dystrophy in early childhood. We used Lrat(-)(/-), a murine model for LCA, to investigate the mechanism of rapid cone degeneration. Although both M and S cone opsins mistrafficked as reported previously, mislocalized M-opsin was degraded whereas mislocalized S-opsin accumulated in Lrat(-)(/-) cones before the onset of massive ventral/central cone degeneration. As the ventral and central retina express higher levels of S-opsin than the dorsal retina in mice, our results may explain why ventral and central cones degenerate more rapidly than dorsal cones in Rpe65(-)(/-) and Lrat(-)(/-) LCA models. In addition, human blue opsin and mouse S-opsin, but not mouse M-opsin or human red/green opsins, aggregated to form cytoplasmic inclusions in transfected cells, which may explain why blue cone function is lost earlier than red/green-cone function in patients with LCA. The aggregation of short-wavelength opsins likely caused rapid cone degenerations through an endoplasmic reticulum stress pathway, as demonstrated in both the Lrat(-)(/-) retina and transfected cells. Replacing rhodopsin with S-opsin in Lrat(-)(/-) rods resulted in mislocalization and aggregation of S-opsin in the inner segment and the synaptic region of rods, ER stress, and dramatically accelerated rod degeneration. Our results demonstrate that cone opsins play a major role in determining the degeneration rate of photoreceptors in LCA. PMID:21555576

  9. Analysis of macular cone photoreceptors in a case of occult macular dystrophy

    Directory of Open Access Journals (Sweden)

    Tojo N

    2013-05-01

    Full Text Available Naoki Tojo Tomoko Nakamura Hironori Ozaki Miyako Oka Toshihiko Oiwake Atsushi HayashiDepartment of Ophthalmology, University of Toyama, Toyama, JapanPurpose: To investigate changes in cone photoreceptors with adaptive optics (AO fundus imaging and spectral domain optical coherence tomography (SD-OCT in a case of occult macular dystrophy (OMD.Patient and methods: Both eyes of a 42-year-old woman diagnosed with OMD were examined. We used an AO fundus camera to obtain images of cone photoreceptors in the macula of the OMD subject and five healthy control subjects. Correlations between the AO images and the SD-OCT images were examined. Cone photoreceptors in eight areas in the macula of OMD and healthy control subjects were analyzed and compared.Results: SD-OCT showed a loss of the cone outer-segment tips line outside of the fovea in both eyes of the subject with OMD. The left eye with decreased visual acuity showed a discontinuous photoreceptor inner-segment and outer-segment line and cone outer-segment tips line at the fovea in SD-OCT and loss of cone mosaics as a dark spot in the AO image. In panoramic AO images and cone-density maps, less cone density was observed in a ring-like region outside the fovea than in the peripheral retina. In most of the areas examined, the cone densities were lower in the OMD eyes than in the healthy control eyes.Conclusions: Cone densities in the macula of the OMD patient were greatly decreased. AO images were found to be useful to evaluate morphologic changes in cone photoreceptors in patients with OMD.Keywords: occult macular dystrophy, adaptive optics, cone photoreceptor, cone analysis, optical coherence tomography

  10. Human Cone Visual Pigment Deletions Spare Sufficient Photoreceptors to Warrant Gene Therapy

    OpenAIRE

    Cideciyan, Artur V.; Hufnagel, Robert B.; Carroll, Joseph; Sumaroka, Alexander; Luo, Xunda; Schwartz, Sharon B.; Dubra, Alfredo; Land, Megan; Michaelides, Michel; Gardner, Jessica C.; Hardcastle, Alison J.; Moore, Anthony T.; Sisk, Robert A; Ahmed, Zubair M.; Kohl, Susanne

    2013-01-01

    Human X-linked blue-cone monochromacy (BCM), a disabling congenital visual disorder of cone photoreceptors, is a candidate disease for gene augmentation therapy. BCM is caused by either mutations in the red (OPN1LW) and green (OPN1MW) cone photoreceptor opsin gene array or large deletions encompassing portions of the gene array and upstream regulatory sequences that would predict a lack of red or green opsin expression. The fate of opsin-deficient cone cells is unknown. We know that rod opsin...

  11. Development and degeneration of cone bipolar cells are independent of cone photoreceptors in a mouse model of retinitis pigmentosa.

    Directory of Open Access Journals (Sweden)

    Miao Chen

    Full Text Available Retinal photoreceptors die during retinal synaptogenesis in a portion of retinal degeneration. Whether cone bipolar cells establish regular retinal mosaics and mature morphologies, and resist degeneration are not completely understood. To explore these issues, we backcrossed a transgenic mouse expressing enhanced green fluorescent protein (EGFP in one subset of cone bipolar cells (type 7 into rd1 mice, a classic mouse model of retinal degeneration, to examine the development and survival of cone bipolar cells in a background of retinal degeneration. Our data revealed that both the development and degeneration of cone bipolar cells are independent of the normal activity of cone photoreceptors. We found that type 7 cone bipolar cells achieved a uniform tiling of the retinal surface and developed normal dendritic and axonal arbors without the influence of cone photoreceptor innervation. On the other hand, degeneration of type 7 cone bipolar cells, contrary to our belief of central-to-peripheral progression, was spatially uniform across the retina independent of the spatiotemporal pattern of cone degeneration. The results have important implications for the design of more effective therapies to restore vision in retinal degeneration.

  12. Restoration of Cone Vision in the CNGA3−/− Mouse Model of Congenital Complete Lack of Cone Photoreceptor Function

    OpenAIRE

    Michalakis, Stylianos; Mühlfriedel, Regine; Tanimoto, Naoyuki; Krishnamoorthy, Vidhyasankar; Koch, Susanne; Fischer, M. Dominik; Becirovic, Elvir; Bai, Lin; Huber, Gesine; Beck, Susanne C.; Fahl, Edda; Büning, Hildegard; Paquet-Durand, François; Zong, Xiangang; Gollisch, Tim

    2010-01-01

    Congenital absence of cone photoreceptor function is associated with strongly impaired daylight vision and loss of color discrimination in human achromatopsia. Here, we introduce viral gene replacement therapy as a potential treatment for this disease in the CNGA3−/− mouse model. We show that such therapy can restore cone-specific visual processing in the central nervous system even if cone photoreceptors had been nonfunctional from birth. The restoration of cone vision was assessed at differ...

  13. Development and degeneration of cone bipolar cells are independent of cone photoreceptors in a mouse model of retinitis pigmentosa

    OpenAIRE

    Miao Chen; Ke Wang; Bin Lin

    2012-01-01

    Retinal photoreceptors die during retinal synaptogenesis in a portion of retinal degeneration. Whether cone bipolar cells establish regular retinal mosaics and mature morphologies, and resist degeneration are not completely understood. To explore these issues, we backcrossed a transgenic mouse expressing enhanced green fluorescent protein (EGFP) in one subset of cone bipolar cells (type 7) into rd1 mice, a classic mouse model of retinal degeneration, to examine the development and survival of...

  14. Loss of Bmi1 causes anomalies in retinal development and degeneration of cone photoreceptors.

    Science.gov (United States)

    Barabino, Andrea; Plamondon, Vicky; Abdouh, Mohamed; Chatoo, Wassim; Flamier, Anthony; Hanna, Roy; Zhou, Shufeng; Motoyama, Noboru; Hébert, Marc; Lavoie, Joëlle; Bernier, Gilbert

    2016-05-01

    Retinal development occurs through the sequential but overlapping generation of six types of neuronal cells and one glial cell type. Of these, rod and cone photoreceptors represent the functional unit of light detection and phototransduction and are frequently affected in retinal degenerative diseases. During mouse development, the Polycomb group protein Bmi1 is expressed in immature retinal progenitors and differentiated retinal neurons, including cones. We show here that Bmi1 is required to prevent post natal degeneration of cone photoreceptors and bipolar neurons and that inactivation of Chk2 or p53 could improve but not overcome cone degeneration in Bmi1(-/-) mice. The retinal phenotype of Bmi1(-/-) mice was also characterized by loss of heterochromatin, activation of tandem repeats, oxidative stress and Rip3-associated necroptosis. In the human retina, BMI1 was preferentially expressed in cones at heterochromatic foci. BMI1 inactivation in human embryonic stem cells was compatible with retinal induction but impaired cone terminal differentiation. Despite this developmental arrest, BMI1-deficient cones recapitulated several anomalies observed in Bmi1(-/-) photoreceptors, such as loss of heterochromatin, activation of tandem repeats and induction of p53, revealing partly conserved biological functions between mouse and man. PMID:26965367

  15. Suppressing thyroid hormone signaling preserves cone photoreceptors in mouse models of retinal degeneration

    OpenAIRE

    Ma, Hongwei; Thapa, Arjun; Morris, Lynsie; Redmond, T Michael; Baehr, Wolfgang; Ding, Xi-Qin

    2014-01-01

    Photoreceptors degenerate in a wide array of hereditary retinal diseases and age-related macular degeneration. There is currently no treatment available for retinal degenerations. While outnumbered roughly 20:1 by rods in the human retina, it is the cones that mediate color vision and visual acuity, and their survival is critical for vision. In this communication, we investigate whether thyroid hormone (TH) signaling affects cone viability in retinal degeneration mouse models. TH signaling is...

  16. Oncostatin M protects rod and cone photoreceptors and promotes regeneration of cone outer segment in a rat model of retinal degeneration.

    Directory of Open Access Journals (Sweden)

    Xin Xia

    Full Text Available Retinitis pigmentosa (RP is a group of photoreceptor degenerative disorders that lead to loss of vision. Typically, rod photoreceptors degenerate first, resulting in loss of night and peripheral vision. Secondary cone degeneration eventually affects central vision, leading to total blindness. Previous studies have shown that photoreceptors could be protected from degeneration by exogenous neurotrophic factors, including ciliary neurotrophic factor (CNTF, a member of the IL-6 family of cytokines. Using a transgenic rat model of retinal degeneration (the S334-ter rat, we investigated the effects of Oncostatin M (OSM, another member of the IL-6 family of cytokines, on photoreceptor protection. We found that exogenous OSM protects both rod and cone photoreceptors. In addition, OSM promotes regeneration of cone outer segments in early stages of cone degeneration. Further investigation showed that OSM treatment induces STAT3 phosphorylation in Müller cells but not in photoreceptors, suggesting that OSM not directly acts on photoreceptors and that the protective effects of OSM on photoreceptors are mediated by Müller cells. These findings support the therapeutic strategy using members of IL-6 family of cytokines for retinal degenerative disorders. They also provide evidence that activation of the STAT3 pathway in Müller cells promotes photoreceptor survival. Our work highlights the importance of Müller cell-photoreceptor interaction in the retina, which may serve as a model of glia-neuron interaction in general.

  17. Distinct and atypical intrinsic and extrinsic cell death pathways between photoreceptor cell types upon specific ablation of Ranbp2 in cone photoreceptors.

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    Kyoung-In Cho

    2013-06-01

    Full Text Available Non-autonomous cell-death is a cardinal feature of the disintegration of neural networks in neurodegenerative diseases, but the molecular bases of this process are poorly understood. The neural retina comprises a mosaic of rod and cone photoreceptors. Cone and rod photoreceptors degenerate upon rod-specific expression of heterogeneous mutations in functionally distinct genes, whereas cone-specific mutations are thought to cause only cone demise. Here we show that conditional ablation in cone photoreceptors of Ran-binding protein-2 (Ranbp2, a cell context-dependent pleiotropic protein linked to neuroprotection, familial necrotic encephalopathies, acute transverse myelitis and tumor-suppression, promotes early electrophysiological deficits, subcellular erosive destruction and non-apoptotic death of cones, whereas rod photoreceptors undergo cone-dependent non-autonomous apoptosis. Cone-specific Ranbp2 ablation causes the temporal activation of a cone-intrinsic molecular cascade highlighted by the early activation of metalloproteinase 11/stromelysin-3 and up-regulation of Crx and CoREST, followed by the down-modulation of cone-specific phototransduction genes, transient up-regulation of regulatory/survival genes and activation of caspase-7 without apoptosis. Conversely, PARP1+ -apoptotic rods develop upon sequential activation of caspase-9 and caspase-3 and loss of membrane permeability. Rod photoreceptor demise ceases upon cone degeneration. These findings reveal novel roles of Ranbp2 in the modulation of intrinsic and extrinsic cell death mechanisms and pathways. They also unveil a novel spatiotemporal paradigm of progression of neurodegeneration upon cell-specific genetic damage whereby a cone to rod non-autonomous death pathway with intrinsically distinct cell-type death manifestations is triggered by cell-specific loss of Ranbp2. Finally, this study casts new light onto cell-death mechanisms that may be shared by human dystrophies with distinct

  18. Integrity of the cone photoreceptor mosaic in oligocone trichromacy

    DEFF Research Database (Denmark)

    Michaelides, Michel; Rha, Jungtae; Dees, Elise W;

    2011-01-01

    Oligocone trichromacy (OT) is an unusual cone dysfunction syndrome characterized by reduced visual acuity, mild photophobia, reduced amplitude of the cone electroretinogram with normal rod responses, normal fundus appearance, and normal or near-normal color vision. It has been proposed that these...

  19. PRE-1, a cis element sufficient to enhance cone- and rod- specific expression in differentiating zebrafish photoreceptors

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    Hurley James B

    2011-01-01

    Full Text Available Abstract Background Appropriate transcriptional regulation is required for cone photoreceptor development and integrity. To date, only a few cis-regulatory elements that control cone photoreceptor-specific expression have been characterised. The alpha-subunit of cone transducin (TαC is specifically expressed in cone photoreceptors and is required for colour vision. In order to better understand the molecular genetics controlling the initiation of cone photoreceptor-specific expression in vivo, we have utilised zebrafish to identify cis-regulatory elements in the upstream promoter region of the TαC gene. Results A 0.5 kb TαC promoter fragment is sufficient to direct cone-specific expression in transgenic larvae. Within this minimal promoter, we identify photoreceptor regulatory element-1 (PRE-1, a unique 41 bp sequence. PRE-1 specifically binds nuclear factors expressed in ocular tissue. PRE-1 is not required for cone-specific expression directed from a 2.5 kb TαC promoter. However, PRE-1-like sequences, with potential functional redundancy, are located in this 2.5 kb promoter. PRE-1-rho which has the highest sequence and structural homology to PRE-1 is located in the rhodopsin promoter. Surprisingly, PRE-1 and PRE-1-rho are functionally distinct. We demonstrate that PRE-1, but not PRE-1-rho, is sufficient to enhance expression from a heterologous UV cone promoter. PRE-1 is also sufficient to enhance expression from a heterologous rhodopsin promoter without altering its rod photoreceptor specificity. Finally, mutations in consensus E-box and Otx sites prevent PRE-1 from forming complexes with eye nuclear protein and enhancing photoreceptor expression. Conclusions PRE-1 is a novel cis-regulatory module that is sufficient to enhance the initiation of photoreceptor-specific gene expression in differentiating rod and cone photoreceptors.

  20. Speed, sensitivity, and stability of the light response in rod and cone photoreceptors: facts and models.

    Science.gov (United States)

    Korenbrot, Juan I

    2012-09-01

    The light responses of rod and cone photoreceptors in the vertebrate retina are quantitatively different, yet extremely stable and reproducible because of the extraordinary regulation of the cascade of enzymatic reactions that link photon absorption and visual pigment excitation to the gating of cGMP-gated ion channels in the outer segment plasma membrane. While the molecular scheme of the phototransduction pathway is essentially the same in rods and cones, the enzymes and protein regulators that constitute the pathway are distinct. These enzymes and regulators can differ in the quantitative features of their functions or in concentration if their functions are similar or both can be true. The molecular identity and distinct function of the molecules of the transduction cascade in rods and cones are summarized. The functional significance of these molecular differences is examined with a mathematical model of the signal-transducing enzymatic cascade. Constrained by available electrophysiological, biochemical and biophysical data, the model simulates photocurrents that match well the electrical photoresponses measured in both rods and cones. Using simulation computed with the mathematical model, the time course of light-dependent changes in enzymatic activities and second messenger concentrations in non-mammalian rods and cones are compared side by side. PMID:22658984

  1. Cone opsin determines the time course of cone photoreceptor degeneration in Leber congenital amaurosis

    OpenAIRE

    Zhang, Tao; Zhang, Ning; Baehr, Wolfgang; Fu, Yingbin

    2011-01-01

    Mutations in RPE65 or lecithin-retinol acyltransferase (LRAT) disrupt 11-cis-retinal recycling and cause Leber congenital amaurosis (LCA), the most severe retinal dystrophy in early childhood. We used Lrat−/−, a murine model for LCA, to investigate the mechanism of rapid cone degeneration. Although both M and S cone opsins mistrafficked as reported previously, mislocalized M-opsin was degraded whereas mislocalized S-opsin accumulated in Lrat−/− cones before the onset of massive ventral/centra...

  2. Mechanisms, pools, and sites of spontaneous vesicle release at synapses of rod and cone photoreceptors.

    Science.gov (United States)

    Cork, Karlene M; Van Hook, Matthew J; Thoreson, Wallace B

    2016-08-01

    Photoreceptors have depolarized resting potentials that stimulate calcium-dependent release continuously from a large vesicle pool but neurons can also release vesicles without stimulation. We characterized the Ca(2+) dependence, vesicle pools, and release sites involved in spontaneous release at photoreceptor ribbon synapses. In whole-cell recordings from light-adapted horizontal cells (HCs) of tiger salamander retina, we detected miniature excitatory post-synaptic currents (mEPSCs) when no stimulation was applied to promote exocytosis. Blocking Ca(2+) influx by lowering extracellular Ca(2+) , by application of Cd(2+) and other agents reduced the frequency of mEPSCs but did not eliminate them, indicating that mEPSCs can occur independently of Ca(2+) . We also measured release presynaptically from rods and cones by examining quantal glutamate transporter anion currents. Presynaptic quantal event frequency was reduced by Cd(2+) or by increased intracellular Ca(2+) buffering in rods, but not in cones, that were voltage clamped at -70 mV. By inhibiting the vesicle cycle with bafilomycin, we found the frequency of mEPSCs declined more rapidly than the amplitude of evoked excitatory post-synaptic currents (EPSCs) suggesting a possible separation between vesicle pools in evoked and spontaneous exocytosis. We mapped sites of Ca(2+) -independent release using total internal reflectance fluorescence (TIRF) microscopy to visualize fusion of individual vesicles loaded with dextran-conjugated pHrodo. Spontaneous release in rods occurred more frequently at non-ribbon sites than evoked release events. The function of Ca(2+) -independent spontaneous release at continuously active photoreceptor synapses remains unclear, but the low frequency of spontaneous quanta limits their impact on noise. PMID:27255664

  3. Quantitative analysis of cone photoreceptor distribution and its relationship with axial length, age, and early age-related macular degeneration.

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    Ryo Obata

    Full Text Available PURPOSE: It has not been clarified whether early age-related macular degeneration (AMD is associated with cone photoreceptor distribution. We used adaptive optics fundus camera to examine cone photoreceptors in the macular area of aged patients and quantitatively analyzed its relationship between the presence of early AMD and cone distribution. METHODS: Sixty cases aged 50 or older were studied. The eyes were examined with funduscopy and spectral-domain optical coherence tomography to exclude the eyes with any abnormalities at two sites of measurement, 2° superior and 5° temporal to the fovea. High-resolution retinal images with cone photoreceptor mosaic were obtained with adaptive optics fundus camera (rtx1, Imagine Eyes, France. After adjusting for axial length, cone packing density was calculated and the relationship with age, axial length, or severity of early AMD based on the age-related eye disease study (AREDS classification was analyzed. RESULTS: Patient's age ranged from 50 to 77, and axial length from 21.7 to 27.5 mm. Mean density in metric units and that in angular units were 24,900 cells/mm2, 2,170 cells/deg2 at 2° superior, and 18,500 cells/mm2, 1,570 cels/deg2 at 5° temporal, respectively. Axial length was significantly correlated with the density calculated in metric units, but not with that in angular units. Age was significantly correlated with the density both in metric and angular units at 2° superior. There was no significant difference in the density in metric and angular units between the eyes with AREDS category one and those with categories two or three. CONCLUSION: Axial length and age were significantly correlated with parafoveal cone photoreceptor distribution. The results do not support that early AMD might influence cone photoreceptor density in the area without drusen or pigment abnormalities.

  4. Multiple rod–cone and cone–rod photoreceptor transmutations in snakes: Evidence from visual opsin gene expression

    Science.gov (United States)

    Simoe, Bruno F; Sampaio, Filipa L.; Loew, Ellis R.; Sanders, Kate L.; Fisher, Robert N.; Hart, Nathan S.; Hunt, David M.; Partridge, Julian C.; Gower, David J.

    2016-01-01

    In 1934, Gordon Walls forwarded his radical theory of retinal photoreceptor ‘transmutation’. This proposed that rods and cones used for scotopic and photopic vision, respectively, were not fixed but could evolve into each other via a series of morphologically distinguishable intermediates. Walls' prime evidence came from series of diurnal and nocturnal geckos and snakes that appeared to have pure-cone or pure-rod retinas (in forms that Walls believed evolved from ancestors with the reverse complement) or which possessed intermediate photoreceptor cells. Walls was limited in testing his theory because the precise identity of visual pigments present in photoreceptors was then unknown. Subsequent molecular research has hitherto neglected this topic but presents new opportunities. We identify three visual opsin genes, rh1, sws1 and lws, in retinal mRNA of an ecologically and taxonomically diverse sample of snakes central to Walls' theory. We conclude that photoreceptors with superficially rod- or cone-like morphology are not limited to containing scotopic or photopic opsins, respectively. Walls' theory is essentially correct, and more research is needed to identify the patterns, processes and functional implications of transmutation. Future research will help to clarify the fundamental properties and physiology of photoreceptors adapted to function in different light levels.

  5. A model for transport of membrane-associated phototransduction polypeptides in rod and cone photoreceptor inner segments

    OpenAIRE

    Karan, Sukanya; Zhang, Houbin; Li, Sha; Frederick, Jeanne M.; Baehr, Wolfgang

    2007-01-01

    We discuss putative mechanisms of membrane protein transport in photoreceptors based on Pde6d and Gucy2e/Gucy2f knockout mice. Knockout of the Pde6d gene encoding PrBP/δ, a prenyl binding protein present in the retina at relatively high levels, was shown to impair transport of G-protein coupled receptor kinase 1 (GRK1) and cone phosphodiesterase α′-subunit (PDE6α′) to the rod and cone outer segments. Other prenylated proteins are minimally affected, suggesting some specificity of interaction....

  6. The disruption of the rod-derived cone viability gene leads to photoreceptor dysfunction and susceptibility to oxidative stress.

    Science.gov (United States)

    Cronin, T; Raffelsberger, W; Lee-Rivera, I; Jaillard, C; Niepon, M-L; Kinzel, B; Clérin, E; Petrosian, A; Picaud, S; Poch, O; Sahel, J-A; Léveillard, T

    2010-07-01

    Rod-derived cone viability factor (RdCVF) is a thioredoxin-like protein, which has therapeutic potential for rod-cone dystrophies such as retinitis pigmentosa (RP). Cone loss in rodent models of RP is effectively reduced by RdCVF treatment. In this study, we investigate the physiological role of RdCVF in the retina by analyzing the phenotype of the mouse lacking the RdCVF gene, Nxnl1. Although the mice do not show an obvious developmental defect, an age-related reduction of both cone and rod function and a delay in the dark-adaptation of the retina are recorded by electroretinogram (ERG). This functional change is accompanied by a 17% reduction in cone density and a 20% reduction in thickness of the outer nuclear layer. The transcriptome of the retina reveals early changes in the expression of genes involved in programmed cell death, stress-response and redox-signaling, which is followed by a generalized injury response with increased microglial activation, GFAP, FGF2 and lipid peroxidation levels. Furthermore, cones of the mice lacking Nxnl1 are more sensitive to oxidative stress with a reduction of 65% in the cone flicker ERG amplitude measured under hyperoxic conditions. We show here that the RdCVF gene, in addition to therapeutic properties, has an essential role in photoreceptor maintenance and resistance to retinal oxidative stress. PMID:20139892

  7. Complementary shifts in photoreceptor spectral tuning unlock the full adaptive potential of ultraviolet vision in birds.

    Science.gov (United States)

    Toomey, Matthew B; Lind, Olle; Frederiksen, Rikard; Curley, Robert W; Riedle, Ken M; Wilby, David; Schwartz, Steven J; Witt, Christopher C; Harrison, Earl H; Roberts, Nicholas W; Vorobyev, Misha; McGraw, Kevin J; Cornwall, M Carter; Kelber, Almut; Corbo, Joseph C

    2016-01-01

    Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax. PMID:27402384

  8. ℮-conome: an automated tissue counting platform of cone photoreceptors for rodent models of retinitis pigmentosa

    Directory of Open Access Journals (Sweden)

    Clérin Emmanuelle

    2011-12-01

    Full Text Available Abstract Background Retinitis pigmentosa is characterized by the sequential loss of rod and cone photoreceptors. The preservation of cones would prevent blindness due to their essential role in human vision. Rod-derived Cone Viability Factor is a thioredoxin-like protein that is secreted by rods and is involved in cone survival. To validate the activity of Rod-derived Cone Viability Factors (RdCVFs as therapeutic agents for treating retinitis Pigmentosa, we have developed e-conome, an automated cell counting platform for retinal flat mounts of rodent models of cone degeneration. This automated quantification method allows for faster data analysis thereby accelerating translational research. Methods An inverted fluorescent microscope, motorized and coupled to a CCD camera records images of cones labeled with fluorescent peanut agglutinin lectin on flat-mounted retinas. In an average of 300 fields per retina, nine Z-planes at magnification X40 are acquired after two-stage autofocus individually for each field. The projection of the stack of 9 images is subject to a threshold, filtered to exclude aberrant images based on preset variables. The cones are identified by treating the resulting image using 13 variables empirically determined. The cone density is calculated over the 300 fields. Results The method was validated by comparison to the conventional stereological counting. The decrease in cone density in rd1 mouse was found to be equivalent to the decrease determined by stereological counting. We also studied the spatiotemporal pattern of the degeneration of cones in the rd1 mouse and show that while the reduction in cone density starts in the central part of the retina, cone degeneration progresses at the same speed over the whole retinal surface. We finally show that for mice with an inactivation of the Nucleoredoxin-like genes Nxnl1 or Nxnl2 encoding RdCVFs, the loss of cones is more pronounced in the ventral retina. Conclusion The automated

  9. Rod and cone photoreceptor cells produce ROS in response to stress in a live retinal explant system.

    LENUS (Irish Health Repository)

    Bhatt, Lavinia

    2010-01-01

    PURPOSE: The production of reactive oxygen species (ROS) can lead to oxidative stress, which is a strong contributory factor to many ocular diseases. In this study, the removal of trophic factors is used as a model system to investigate the effects of stress in the retina. The aims were to determine if both rod and cone photoreceptor cells produce ROS when they are deprived of trophic factor support and to demonstrate if the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox) enzymes are responsible for this ROS production. METHODS: Retinas were explanted from mice aged between postnatal days 8-10 and cultured overnight. The following morning, confocal microscopy combined with various fluorescent probes was used to detect the production of ROS. Each time peanut agglutinin (PNA), a cone photoreceptor marker, was used to facilitate orientation of the retina. Dihydroethidium and dihydrorhodamine 123 (DHR123) were used to determine which cells produce ROS. Subsequently, western blots of retinal serial sections were used to detect the presence of Noxs in the different retinal layers. The Nox inhibitor apocynin was then tested to determine if it altered the production of ROS within these cells. RESULTS: Live retinal explants, viewed at high magnifications using confocal microscopy, displayed an increase in the fluorescent products of dihydroethidium and DHR123 upon serum removal when compared to controls. DHR123 fluorescence, once oxidized, localized to mitochondria and was found in the same focal plane as the PNA staining. This showed that cones and rods produced ROS when stressed. Retinal serial sectioning established that the photoreceptor layer expressed Nox4, dual oxidase (Duox) 1, and Duox2 at varying levels. Finally, the Nox inhibitor apocynin decreased the burst stimulated by the stress of serum removal. CONCLUSIONS: Confocal microscopy and PNA staining allowed differentiation of cell types within the outermost layers of the retina, demonstrating

  10. NLRP3 inflammasome activation drives bystander cone photoreceptor cell death in a P23H rhodopsin model of retinal degeneration.

    Science.gov (United States)

    Viringipurampeer, Ishaq A; Metcalfe, Andrew L; Bashar, Abu E; Sivak, Olena; Yanai, Anat; Mohammadi, Zeinabsadat; Moritz, Orson L; Gregory-Evans, Cheryl Y; Gregory-Evans, Kevin

    2016-04-15

    The molecular signaling leading to cell death in hereditary neurological diseases such as retinal degeneration is incompletely understood. Previous neuroprotective studies have focused on apoptotic pathways; however, incomplete suppression of cell death with apoptosis inhibitors suggests that other mechanisms are at play. Here, we report that different signaling pathways are activated in rod and cone photoreceptors in the P23H rhodopsin mutant rat, a model representing one of the commonest forms of retinal degeneration. Up-regulation of the RIP1/RIP3/DRP1 axis and markedly improved survival with necrostatin-1 treatment highlighted necroptosis as a major cell-death pathway in degenerating rod photoreceptors. Conversely, up-regulation of NLRP3 and caspase-1, expression of mature IL-1β and IL-18 and improved cell survival with N-acetylcysteine treatment suggested that inflammasome activation and pyroptosis was the major cause of cone cell death. This was confirmed by generation of the P23H mutation on an Nlrp3-deficient background, which preserved cone viability. Furthermore, Brilliant Blue G treatment inhibited inflammasome activation, indicating that the 'bystander cell death' phenomenon was mediated through the P2RX7 cell-surface receptor. Here, we identify a new pathway in cones for bystander cell death, a phenomenon important in development and disease in many biological systems. In other retinal degeneration models different cell-death pathways are activated, which suggests that the particular pathways that are triggered are to some extent genotype-specific. This also implies that neuroprotective strategies to limit retinal degeneration need to be customized; thus, different combinations of inhibitors will be needed to target the specific pathways in any given disease. PMID:27008885

  11. A novel in vivo model of focal light emitting diode-induced cone-photoreceptor phototoxicity: neuroprotection afforded by brimonidine, BDNF, PEDF or bFGF.

    Directory of Open Access Journals (Sweden)

    Arturo Ortín-Martínez

    Full Text Available We have investigated the effects of light-emitting diode (LED-induced phototoxicity (LIP on cone-photoreceptors and their protection with brimonidine (BMD, brain-derived neurotrophic factor (BDNF, pigment epithelium-derived factor (PEDF, ciliary neurotrophic factor (CNTF or basic fibroblast growth factor (bFGF. In anesthetized, dark adapted, adult albino rats a blue (400 nm LED was placed perpendicular to the cornea (10 sec, 200 lux and the effects were investigated using Spectral Domain Optical Coherence Tomography (SD-OCT and/or analysing the retina in oriented cross-sections or wholemounts immune-labelled for L- and S-opsin and counterstained with the nuclear stain DAPI. The effects of topical BMD (1% or, intravitreally injected BDNF (5 µg, PEDF (2 µg, CNTF (0.4 µg or bFGF (1 µg after LIP were examined on wholemounts at 7 days. SD-OCT showed damage in a circular region of the superotemporal retina, whose diameter varied from 1,842.4±84.5 µm (at 24 hours to 1,407.7±52.8 µm (at 7 days. This region had a progressive thickness diminution from 183.4±5 µm (at 12 h to 114.6±6 µm (at 7 d. Oriented cross-sections showed within the light-damaged region of the retina massive loss of rods and cone-photoreceptors. Wholemounts documented a circular region containing lower numbers of L- and S-cones. Within a circular area (1 mm or 1.3 mm radius, respectively in the left and in its corresponding region of the contralateral-fellow-retina, total L- or S-cones were 7,118±842 or 661±125 for the LED exposed retinas (n = 7 and 14,040±1,860 or 2,255±193 for the fellow retinas (n = 7, respectively. BMD, BDNF, PEDF and bFGF but not CNTF showed significant neuroprotective effects on L- or S-cones. We conclude that LIP results in rod and cone-photoreceptor loss, and is a reliable, quantifiable model to study cone-photoreceptor degeneration. Intravitreal BDNF, PEDF or bFGF, or topical BMD afford significant cone neuroprotection in this model.

  12. Complementary shifts in photoreceptor spectral tuning unlock the full adaptive potential of ultraviolet vision in birds

    Science.gov (United States)

    Toomey, Matthew B; Lind, Olle; Frederiksen, Rikard; Curley, Robert W; Riedle, Ken M; Wilby, David; Schwartz, Steven J; Witt, Christopher C; Harrison, Earl H; Roberts, Nicholas W; Vorobyev, Misha; McGraw, Kevin J; Cornwall, M Carter; Kelber, Almut; Corbo, Joseph C

    2016-01-01

    Color vision in birds is mediated by four types of cone photoreceptors whose maximal sensitivities (λmax) are evenly spaced across the light spectrum. In the course of avian evolution, the λmax of the most shortwave-sensitive cone, SWS1, has switched between violet (λmax > 400 nm) and ultraviolet (λmax DOI: http://dx.doi.org/10.7554/eLife.15675.001 PMID:27402384

  13. Photoreceptor fine structure in the bobtail goanna (Tiliqua rugosa)

    OpenAIRE

    Braekevelt, Charlie R.

    1989-01-01

    The fine structure of the retinal photoreceptors has been studied by light and electron microscopy in the bobtail goanna (Tiliqua rugosa) an Australian diurna1 lizard. The photoreceptors in this species are readily divisible into rods or cones based on morphological criteria. Single cones are the dominate cell type with a cone:rod ratio of about 80: 1. No multiple photoreceptors were present nor was a photoreceptor mosiac observed. Cones are large cells with a ...

  14. Mouse Ganglion-Cell Photoreceptors Are Driven by the Most Sensitive Rod Pathway and by Both Types of Cones

    OpenAIRE

    Shijun Weng; Estevez, Maureen E.; Berson, David M.

    2013-01-01

    Intrinsically photosensitive retinal ganglion cells (iprgcs) are depolarized by light by two mechanisms: directly, through activation of their photopigment melanopsin; and indirectly through synaptic circuits driven by rods and cones. To learn more about the rod and cone circuits driving ipRGCs, we made multielectrode array (MEA) and patch-clamp recordings in wildtype and genetically modified mice. Rod-driven ON inputs to ipRGCs proved to be as sensitive as any reaching the conventional gangl...

  15. Photoreceptor engineering

    OpenAIRE

    Thea eZiegler; Andreas eMöglich

    2015-01-01

    Sensory photoreceptors not only control diverse adaptive responses in Nature, but as light-regulated actuators they also provide the foundation for optogenetics, the non-invasive and spatiotemporally precise manipulation of cellular events by light. Novel photoreceptors have been engineered that establish control by light over manifold biological processes previously inaccessible to optogenetic intervention. Recently, photoreceptor engineering has witnessed a rapid development, and light-regu...

  16. Regulation of photoreceptor gap junction phosphorylation by adenosine in zebrafish retina

    OpenAIRE

    Li, Hongyan; Alice Z. Chuang; O’Brien, John

    2014-01-01

    Electrical coupling of photoreceptors through gap junctions suppresses voltage noise, routes rod signals into cone pathways, expands the dynamic range of rod photoreceptors in high scotopic and mesopic illumination, and improves detection of contrast and small stimuli. In essentially all vertebrates, connexin 35/36 (gene homologues Cx36 in mammals, Cx35 in other vertebrates) is the major gap junction protein observed in photoreceptors, mediating rod-cone, cone-cone, and possibly rod-rod commu...

  17. What drives cell morphogenesis - a look inside the vertebrate photoreceptor

    OpenAIRE

    Kennedy, Breandan; Malicki, Jarema

    2009-01-01

    Vision mediating photoreceptor cells are specialised light-sensitive neurons in the outer layer of the vertebrate retina. The human retina contains approximately 130 million of such photoreceptors which enable images of the external environment to be captured at high-resolution and high–sensitivity (Forrester et al., 2003). Rod and cone photoreceptor subtypes are further specialised for sensing light in low and high illumination, respectively. To enable visual function, these photoreceptors h...

  18. Differences in calcium homeostasis between retinal rod and cone photoreceptors revealed by the effects of voltage on the cGMP-gated conductance in intact cells

    OpenAIRE

    1994-01-01

    We measured currents under voltage clamp in intact retinal rod photoreceptors with tight seal electrodes in the perforated patch mode. In the dark, membrane depolarization to voltages > or = +20 mV activates a time- and voltage-dependent outward current in the outer segment. This dark voltage-activated current (DVAC) increases in amplitude with a sigmoidal time course that is voltage dependent. DVAC reaches its maximum enhancement of approximately 30% in 4-6 s at +60 mV. DVAC is entirely supp...

  19. A Pro23His Mutation Alters Prenatal Rod Photoreceptor Morphology in a Transgenic Swine Model of Retinitis Pigmentosa

    OpenAIRE

    Scott, Patrick A.; Fernandez de Castro, Juan P.; Kaplan, Henry J.; McCall, Maureen A.

    2014-01-01

    Prenatal expression of mutant rhodopsin alters the normal morphological and functional development of rod photoreceptors in TgP23H swine embryos. Despite this significant change, cone photoreceptors are unaffected.

  20. Synaptic plasticity in GNGA3-/- mice: Cone bipolar cells react up0onthe missing cone input and form ectopic synapses with rods

    OpenAIRE

    Humphries, Peter

    2006-01-01

    PUBLISHED In the mammalian retina, rods and cones connect to distinct sets of bipolar cells. Rods are presynaptic to a single type of rod bipolar cell, whereas cones connect to different types of cone bipolar cells. Synaptic rewiring between cone photoreceptor terminals and rod bipolar cell dendrites has been described as a general result of photoreceptor degeneration. To investigate whether cone bipolar cells also show synaptic plasticity in the absence of cone input, we studied the conne...

  1. Characterisation of the canine rod-cone dysplasia type one gene (rod photoreceptor cGMP phosphodiesterase beta subunit (PDEB)) - a model for human retinitis pigmentosa

    Energy Technology Data Exchange (ETDEWEB)

    Clements, P.J.M.; Gregory, C.Y. [Univ. of London (United Kingdom); Petersen-Jones, S.M. [Univ. of Edinburgh (United Kingdom)

    1994-09-01

    Rod-cone dysplasia type one (rod-1) is an early onset, autosomal recessive retinal dystrophy segregating in the Irish setter breed. It is a model for certain forms of human autosomal recessive retinitis pigmentosa (arRP) caused by mutations in the same gene, PDEB. We confirmed the codon 807 Trp to Stop mutation and were the first to show cosegregation of the mutant allele with disease in a pedigree. We believe that this currently represents the best animal model available for some aspects of arRP, since canine tissues are relatively easy to access compared to human and yet the canine eye is of comparable size, unlike that of the rd mouse. This facilitates therapeutic intervention particularly at the subretinal level. In order to more fully investigate this model we have been characterizing the PDEB gene in the normal dog. Using PCR we have partially mapped the intron/exon structure, demonstrating a very high degree of evolutionary conservation with the mouse and human genes. RT-PCR has been used to reveal expression in a variety of neural and non-neural tissues. A PCR product spanning exons 19 to 22 (which also contains the site for the rcd-1 mutation) is detected in retina but also in tissues such as visual cortex, cerebral cortex, cerebellum, lateral geniculate nucleus, adrenal gland, lung, kidney and ovary. All of these tissues gave a negative result with primers for rds/peripherin, a gene which is expressed in rods and cones. This raises interesting questions about the regulation of PDEB transcripts which is initially being investigated by Northern analysis. In addition, anchored PCR techniques have generated upstream genomic sequences and we are currently mapping the 5{prime} extent of the mRNA transcript in the retina. This will facilitate the analysis of potential upstream promoter elements involved in directing expression.

  2. Retinal Photoreceptor Fine Structure in some reptiles

    Directory of Open Access Journals (Sweden)

    Fairoze Khattab; Fahmy I. Khattab; Nagui Fares and Aman Zaki

    2004-12-01

    Full Text Available The structure of the photoreceptors of four different reptiles: the homed viper Cerastes cerastes (diurnal and nocturnal, the European Chameleo chameleon (diurnal, the gold skink Eumeces schneidrii (diurnal and the Egyptian gecko, Tarentola annularis (nocturnal has been investigated by light and electron microscopy. The photoreceptors of diurnal reptiles were mainly of the cone type and those of nocturnal were mainly rods. The ellipsoid region of both double rods in the nocturnals and large single cones in the species having both nocturnals and diurnal activity, consist of several mitochondria arranged in a remarkable radially gradient architecture which accommodates with the specific function of this region as a focusing device helping to condense light onto the outer segments. Moreover the principle cone of double cone and single cone of diurnal reptiles possessed a large oil droplet in the region between the inner segment and outer segment. This droplet is thought to play a role in filtering light and so doing enhanced contrast reduce glare and lessen chromatic aberration. It is worth to mention that the outer segment of rods in nocturnal reptiles approaches a length of approximately four folds the length of the inner segments of the same photoreceptors cells. This character is of a particular interest, since the outer segment is the site of photopigments and the increase in its length magnifies its ability of light and consequently accommodate with the night vision.

  3. The role of opsin in circadian regulation and photoreceptor degeneration

    NARCIS (Netherlands)

    Janssen, Jannie

    2005-01-01

    The eye is the sensory organ that enables us to detect light necessary for image formation. Within the eye the light-sensitive retina contains specialized rod and cone photoreceptor cells. These cells are able to absorb light by means of light-sensitive membrane proteins (rhodopsin and cone-opsins),

  4. Patterning the Cone Mosaic Array in Zebrafish Retina Requires Specification of Ultraviolet-Sensitive Cones

    OpenAIRE

    Raymond, Pamela A.; Colvin, Steven M.; Jabeen, Zahera; Nagashima, Mikiko; Barthel, Linda K; Hadidjojo, Jeremy; Popova, Lilia; Pejaver, Vivek R.; Lubensky, David K.

    2014-01-01

    Cone photoreceptors in teleost fish are organized in precise, crystalline arrays in the epithelial plane of the retina. In zebrafish, four distinct morphological/spectral cone types occupy specific, invariant positions within a regular lattice. The cone lattice is aligned orthogonal and parallel to circumference of the retinal hemisphere: it emerges as cones generated in a germinal zone at the retinal periphery are incorporated as single-cell columns into the cone lattice. Genetic disruption ...

  5. A complex carotenoid palette tunes avian colour vision.

    Science.gov (United States)

    Toomey, Matthew B; Collins, Aaron M; Frederiksen, Rikard; Cornwall, M Carter; Timlin, Jerilyn A; Corbo, Joseph C

    2015-10-01

    The brilliantly coloured cone oil droplets of the avian retina function as long-pass cut-off filters that tune the spectral sensitivity of the photoreceptors and are hypothesized to enhance colour discrimination and improve colour constancy. Although it has long been known that these droplets are pigmented with carotenoids, their precise composition has remained uncertain owing to the technical challenges of measuring these very small, dense and highly refractile optical organelles. In this study, we integrated results from high-performance liquid chromatography, hyperspectral microscopy and microspectrophotometry to obtain a comprehensive understanding of oil droplet carotenoid pigmentation in the chicken (Gallus gallus). We find that each of the four carotenoid-containing droplet types consists of a complex mixture of carotenoids, with a single predominant carotenoid determining the wavelength of the spectral filtering cut-off. Consistent with previous reports, we find that the predominant carotenoid type in the oil droplets of long-wavelength-sensitive, medium-wavelength-sensitive and short-wavelength-sensitive type 2 cones are astaxanthin, zeaxanthin and galloxanthin, respectively. In addition, the oil droplet of the principal member of the double cone contains a mixture of galloxanthin and two hydroxycarotenoids (lutein and zeaxanthin). Short-wavelength-absorbing apocarotenoids are present in all of the droplet types, providing filtering of light in a region of the spectrum where filtering by hydroxy- and ketocarotenoids may be incomplete. Thus, birds rely on a complex palette of carotenoid pigments within their cone oil droplets to achieve finely tuned spectral filtering. PMID:26446559

  6. Mutations in PCDH21 cause autosomal recessive cone-rod dystrophy

    DEFF Research Database (Denmark)

    Østergaard, Elsebet; Batbayli, M; Dunø, Morten; Vilhelmsen, K; Rosenberg, T

    2010-01-01

    Cone-rod dystrophy is a retinal dystrophy with early loss of cone photoreceptors and a parallel or subsequent loss of rod photoreceptors. It may be syndromic, but most forms are non-syndromic with autosomal dominant, autosomal recessive or X-linked recessive inheritance.......Cone-rod dystrophy is a retinal dystrophy with early loss of cone photoreceptors and a parallel or subsequent loss of rod photoreceptors. It may be syndromic, but most forms are non-syndromic with autosomal dominant, autosomal recessive or X-linked recessive inheritance....

  7. Retinal photoreceptor fine structure in the short-tailed stingray. Dasyatis brevicaudata

    OpenAIRE

    Braekevelt, Charlie R.

    1994-01-01

    The fine structure of the retinal photoreceptors has been studied by light and electron microscopy in the short-tailed stingray (Dasyatis brevicaudata). The duplex retina of this elasmobranch contains rods and cones in a ratio of about 10:l. No multiple receptors were noted nor was a repeating or mosaic arrangenient of the cones obvious. Only lightadapted specimens were studied but retinomotor movements of the photoreceptors were felt to be minimal or absen...

  8. Cone opsins, colour blindness and cone dystrophy: Genotype-phenotype correlations.

    Science.gov (United States)

    Gardner, J C; Michaelides, M; Hardcastle, A J

    2016-01-01

    X-linked cone photoreceptor disorders caused by mutations in the OPN1LW (L) and OPN1MW (M) cone opsin genes on chromosome Xq28 include a range of conditions from mild stable red-green colour vision deficiencies to severe cone dystrophies causing progressive loss of vision and blindness. Advances in molecular genotyping and functional analyses of causative variants, combined with deep retinal phenotyping, are unravelling genetic mechanisms underlying the variability of cone opsin disorders. PMID:27245533

  9. 一种在紫外敏感型视锥细胞中特异表达 tdTomato 的转基因斑马鱼系的构建%Establishment of a transgenic zebrafish line with tdTomato expression in the ultraviolet-sensitive cone photoreceptors

    Institute of Scientific and Technical Information of China (English)

    陈哲; 宋著; 王雅冬; 赵呈天

    2015-01-01

    目的 鉴于目前对斑马鱼视锥细胞视蛋白运输机制并不明确,且缺乏相应的抗体,本实验拟构建一种可以在视锥细胞中特异表达荧光的转基因斑马鱼. 方法 利用编码紫外敏感型视蛋白基因( sws1)的启动子,构建了一种在紫外敏感型视锥细胞中特异表达红色荧光蛋白tdTomato的转基因斑马鱼. 同时,将tdTomato荧光蛋白与非洲爪蟾rhodopsin蛋白末端44个氨基酸相融合,将该融合蛋白定位于紫外敏感型视锥细胞的外节段,进而可模拟内源性视蛋白的定位. 结果 共筛选出三种不同品系的转基因斑马鱼,经过免疫组化分析,确定其中一种转基因品系是正确的目标品系. 结论 该转基因斑马鱼的构建将会为进一步研究视锥细胞中视蛋白的运输机制提供帮助.%Objective To better understand the mechanisms of cone opsin transport , we set to generate a trans-genic zebrafish line with red fluorescence proteins expressing in the cone photoreceptors .Methods We used sws1 promot-er to drive the expression of a chimerical protein , in which the last 44 amino acids of rhodopsin of Xenopus laevis were fused to the C-terminus of tdTomato to restrict its localization to the outer segment of photoreceptors .Results We successfully i-solated such a transgenic zebrafish line and confirmed the localization of tdTomato by immunostaining analysis .Conclu-sions This transgenic zebrafish line will help us to better understand the transport mechanisms of cone opsins , especially the transport in live photoreceptors .

  10. Retinal photoreceptor fine structure in the mallard duck (Anas platyrhinchos)

    OpenAIRE

    Braekevelt, Charlie R.

    1990-01-01

    The retinal photoreceptors of the mallard duck (Anas platyrhynchos) consist of rods, single cones and double (unequal) cones present in a ratio of about 1:2:1. The rods have relatively large cylindrical outer segments which in the light-adapted state reach to the retinal epithelial (RPE) cell bodies and are surrounded by the pigment-laden apical processes of these RPE cells. The inner segment displays an apically located ellipsoid of mitochondria and plentiful ...

  11. Noninvasive imaging of the thirteen-lined ground squirrel photoreceptor mosaic.

    Science.gov (United States)

    Sajdak, Benjamin; Sulai, Yusufu N; Langlo, Christopher S; Luna, Gabriel; Fisher, Steven K; Merriman, Dana K; Dubra, Alfredo

    2016-01-01

    Ground squirrels are an increasingly important model for studying visual processing, retinal circuitry, and cone photoreceptor function. Here, we demonstrate that the photoreceptor mosaic can be longitudinally imaged noninvasively in the 13-lined ground squirrel (Ictidomys tridecemlineatus) using confocal and nonconfocal split-detection adaptive optics scanning ophthalmoscopy using 790 nm light. Photoreceptor density, spacing, and Voronoi analysis are consistent with that of the human cone mosaic. The high imaging success rate and consistent image quality in this study reinforce the ground squirrel as a practical model to aid drug discovery and testing through longitudinal imaging on the cellular scale. PMID:26923645

  12. ERGs, cone-isolating VEPs and analytical techniques in children with cone dysfunction syndromes.

    Science.gov (United States)

    Kelly, John P; Crognale, Michael A; Weiss, Avery H

    2003-05-01

    Photoreceptor and post-receptoral function in children with congenital and acquired cone disorders was measured by full-field electroretinogram (ERG) and transient visual evoked potentials (VEPs). Subjects were five rod monochromats (RM), five with cone dystrophy (CD), and 30 controls. Patients were diagnosed by clinical findings, ERGs, and standard color vision tests. VEP stimuli were check reversals and color grating onsets that stimulated each photoreceptor type (L-, M-, or S-cones) or post-receptoral pathways (L-M, white/black). VEP signal-to-noise ratios (S/N) were calculated by Fourier analysis of VEP epochs. All RM patients showed extinguished cone ERGs. A near normal S-cone VEP was recorded from a blue-cone rod monochromat without any signal from the L- or M-cone stimuli. Two other RM patients were classified as incomplete RM based on a low-level VEP signal from either L- or M-cone stimuli. CD patients had mildly to severely reduced ERGs and VEPs were abnormal to all cone-isolating stimuli. The VEP S/N ratio was not significantly correlated with the amount of rod contrast in the color stimuli. Color VEPs provide an objective assessment of macular cone function in children with cone dysfunction syndromes that is more sensitive to residual central cone function than standard full-field ERGs. VEP techniques may be useful in the early detection of cone loss in children, especially in children who do not tolerate ERG testing. PMID:12737507

  13. Retinal Thickening and Photoreceptor Loss in HIV Eyes without Retinitis.

    Directory of Open Access Journals (Sweden)

    Cheryl A Arcinue

    Full Text Available To determine the presence of structural changes in HIV retinae (i.e., photoreceptor density and retinal thickness in the macula compared with age-matched HIV-negative controls.Cohort of patients with known HIV under CART (combination Antiretroviral Therapy treatment were examined with a flood-illuminated retinal AO camera to assess the cone photoreceptor mosaic and spectral-domain optical coherence tomography (SD-OCT to assess retinal layers and retinal thickness.Twenty-four eyes of 12 patients (n = 6 HIV-positive and 6 HIV-negative were imaged with the adaptive optics camera. In each of the regions of interest studied (nasal, temporal, superior, inferior, the HIV group had significantly less mean cone photoreceptor density compared with age-matched controls (difference range, 4,308-6,872 cones/mm2. A different subset of forty eyes of 20 patients (n = 10 HIV-positive and 10 HIV-negative was included in the retinal thickness measurements and retinal layer segmentation with the SD-OCT. We observed significant thickening in HIV positive eyes in the total retinal thickness at the foveal center, and in each of the three horizontal B-scans (through the macular center, superior, and inferior to the fovea. We also noted that the inner retina (combined thickness from ILM through RNFL to GCL layer was also significantly thickened in all the different locations scanned compared with HIV-negative controls.Our present study shows that the cone photoreceptor density is significantly reduced in HIV retinae compared with age-matched controls. HIV retinae also have increased macular retinal thickness that may be caused by inner retinal edema secondary to retinovascular disease in HIV. The interaction of photoreceptors with the aging RPE, as well as possible low-grade ocular inflammation causing diffuse inner retinal edema, may be the key to the progressive vision changes in HIV-positive patients without overt retinitis.

  14. Bioinformatic identification of novel putative photoreceptor specific cis-elements

    Directory of Open Access Journals (Sweden)

    Knox Barry E

    2007-10-01

    Full Text Available Abstract Background Cell specific gene expression is largely regulated by different combinations of transcription factors that bind cis-elements in the upstream promoter sequence. However, experimental detection of cis-elements is difficult, expensive, and time-consuming. This provides a motivation for developing bioinformatic methods to identify cis-elements that could prioritize future experimental studies. Here, we use motif discovery algorithms to predict transcription factor binding sites involved in regulating the differences between murine rod and cone photoreceptor populations. Results To identify highly conserved motifs enriched in promoters that drive expression in either rod or cone photoreceptors, we assembled a set of murine rod-specific, cone-specific, and non-photoreceptor background promoter sequences. These sets were used as input to a newly devised motif discovery algorithm called Iterative Alignment/Modular Motif Selection (IAMMS. Using IAMMS, we predicted 34 motifs that may contribute to rod-specific (19 motifs or cone-specific (15 motifs expression patterns. Of these, 16 rod- and 12 cone-specific motifs were found in clusters near the transcription start site. New findings include the observation that cone promoters tend to contain TATA boxes, while rod promoters tend to be TATA-less (exempting Rho and Cnga1. Additionally, we identify putative sites for IL-6 effectors (in rods and RXR family members (in cones that can explain experimental data showing changes to cell-fate by activating these signaling pathways during rod/cone development. Two of the predicted motifs (NRE and ROP2 have been confirmed experimentally to be involved in cell-specific expression patterns. We provide a full database of predictions as additional data that may contain further valuable information. IAMMS predictions are compared with existing motif discovery algorithms, DME and BioProspector. We find that over 60% of IAMMS predictions are confirmed by

  15. Retinal photoreceptors and visual pigments in Boa constrictor imperator.

    Science.gov (United States)

    Sillman, A J; Johnson, J L; Loew, E R

    2001-09-01

    The photoreceptors of Boa constrictor, a boid snake of the subfamily Boinae, were examined with scanning electron microscopy and microspectrophotometry. The retina of B. constrictor is duplex but highly dominated by rods, cones comprising 11% of the photoreceptor population. The rather tightly packed rods have relatively long outer segments with proximal ends that are somewhat tapered. There are two morphologically distinct, single cones. The most common cone by far has a large inner segment and a relatively stout outer segment. The second cone, seen only infrequently, has a substantially smaller inner segment and a finer outer segment. The visual pigments of B. constrictor are virtually identical to those of the pythonine boid, Python regius. Three different visual pigments are present, all based on vitamin A(1.) The visual pigment of the rods has a wavelength of peak absorbance (lambda(max)) at 495 +/- 2 nm. The visual pigment of the more common, large cone has a lambda(max) at 549 +/- 1 nm. The small, rare cone contains a visual pigment with lambda(max) at 357 +/- 2 nm, providing the snake with sensitivity in the ultraviolet. We suggest that B. constrictor might employ UV sensitivity to locate conspecifics and/or to improve hunting efficiency. The data indicate that wavelength discrimination above 430 nm would not be possible without some input from the rods. PMID:11550183

  16. Loss of the Metalloprotease ADAM9 Leads to Cone-Rod Dystrophy in Humans and Retinal Degeneration in Mice

    OpenAIRE

    Parry, David A.; Toomes, Carmel; Bida, Lina; Danciger, Michael; Towns, Katherine V.; McKibbin, Martin; Jacobson, Samuel G.; Logan, Clare V.; Ali, Manir; Bond, Jacquelyn; Chance, Rebecca; Swendeman, Steven; Daniele, Lauren L.; Springell, Kelly; Adams, Matthew

    2009-01-01

    Cone-rod dystrophy (CRD) is an inherited progressive retinal dystrophy affecting the function of cone and rod photoreceptors. By autozygosity mapping, we identified null mutations in the ADAM metallopeptidase domain 9 (ADAM9) gene in four consanguineous families with recessively inherited early-onset CRD. We also found reduced photoreceptor responses in Adam9 knockout mice, previously reported to be asymptomatic. In 12-month-old knockout mice, photoreceptors appear normal, but the apical proc...

  17. Pineal photoreceptor cells are required for maintaining the circadian rhythms of behavioral visual sensitivity in zebrafish.

    Directory of Open Access Journals (Sweden)

    Xinle Li

    Full Text Available In non-mammalian vertebrates, the pineal gland functions as the central pacemaker that regulates the circadian rhythms of animal behavior and physiology. We generated a transgenic zebrafish line [Tg(Gnat2:gal4-VP16/UAS:nfsB-mCherry] in which the E. coli nitroreductase is expressed in pineal photoreceptor cells. In developing embryos and young adults, the transgene is expressed in both retinal and pineal photoreceptor cells. During aging, the expression of the transgene in retinal photoreceptor cells gradually diminishes. By 8 months of age, the Gnat2 promoter-driven nitroreductase is no longer expressed in retinal photoreceptor cells, but its expression in pineal photoreceptor cells persists. This provides a tool for selective ablation of pineal photoreceptor cells, i.e., by treatments with metronidazole. In the absence of pineal photoreceptor cells, the behavioral visual sensitivity of the fish remains unchanged; however, the circadian rhythms of rod and cone sensitivity are diminished. Brief light exposures restore the circadian rhythms of behavioral visual sensitivity. Together, the data suggest that retinal photoreceptor cells respond to environmental cues and are capable of entraining the circadian rhythms of visual sensitivity; however, they are insufficient for maintaining the rhythms. Cellular signals from the pineal photoreceptor cells may be required for maintaining the circadian rhythms of visual sensitivity.

  18. Retinoschisin, a photoreceptor-secreted protein, and its interaction with bipolar and muller cells

    OpenAIRE

    Reid, SNM; Yamashita, C; Farber, D B

    2003-01-01

    Usually, photoreceptors interact with other retinal cells through the neurotransmitter glutamate. Here we describe a nonsynaptic interaction via a secreted protein, retinoschisin. Using in situ hybridization, we found that from early postnatal life retinoschisin mRNA is present only in the outer retina of the mouse, and with single-cell RT-PCR we demonstrated its localization in rod and cone photoreceptor cells but not in Muller cells. Western blot analyses of proteins from cultured ocular ti...

  19. Photoreceptor degeneration and rd1 mutation in the grizzled/mocha mouse strain.

    Science.gov (United States)

    Qiao, Xiaoxi; Pennesi, Mark; Seong, Eunju; Gao, Hua; Burmeister, Margit; Wu, Samuel M

    2003-04-01

    The mocha mouse is a spontaneous mutant carrying a defective adaptor-like protein complex AP-3delta subunit. We examined retinal function and histology of the mocha mutant. We found that not only mocha homozygotes but also other littermates in the inbred strain are blind due to severe defects in both rod and cone photoreceptors on electroretinogram recordings. The functional deficit was caused by rapid, early postnatal photoreceptor degeneration. Genotyping confirmed the presence of a viral insertion of rd1 gene in the mocha strain. We conclude that rd1 allele contamination is primarily responsible for photoreceptor degeneration, and caution against behavioral tests with visual cues in the present stocks. PMID:12668055

  20. The B3 Subunit of the Cone Cyclic Nucleotide-gated Channel Regulates the Light Responses of Cones and Contributes to the Channel Structural Flexibility.

    Science.gov (United States)

    Ding, Xi-Qin; Thapa, Arjun; Ma, Hongwei; Xu, Jianhua; Elliott, Michael H; Rodgers, Karla K; Smith, Marci L; Wang, Jin-Shan; Pittler, Steven J; Kefalov, Vladimir J

    2016-04-15

    Cone photoreceptor cyclic nucleotide-gated (CNG) channels play a pivotal role in cone phototransduction, which is a process essential for daylight vision, color vision, and visual acuity. Mutations in the cone channel subunits CNGA3 and CNGB3 are associated with human cone diseases, including achromatopsia, cone dystrophies, and early onset macular degeneration. Mutations in CNGB3 alone account for 50% of reported cases of achromatopsia. This work investigated the role of CNGB3 in cone light response and cone channel structural stability. As cones comprise only 2-3% of the total photoreceptor population in the wild-type mouse retina, we used Cngb3(-/-)/Nrl(-/-) mice with CNGB3 deficiency on a cone-dominant background in our study. We found that, in the absence of CNGB3, CNGA3 was able to travel to the outer segments, co-localize with cone opsin, and form tetrameric complexes. Electroretinogram analyses revealed reduced cone light response amplitude/sensitivity and slower response recovery in Cngb3(-/-)/Nrl(-/-) mice compared with Nrl(-/-) mice. Absence of CNGB3 expression altered the adaptation capacity of cones and severely compromised function in bright light. Biochemical analysis demonstrated that CNGA3 channels lacking CNGB3 were more resilient to proteolysis than CNGA3/CNGB3 channels, suggesting a hindered structural flexibility. Thus, CNGB3 regulates cone light response kinetics and the channel structural flexibility. This work advances our understanding of the biochemical and functional role of CNGB3 in cone photoreceptors. PMID:26893377

  1. Calcium channel-dependent molecular maturation of photoreceptor synapses.

    Directory of Open Access Journals (Sweden)

    Nawal Zabouri

    Full Text Available Several studies have shown the importance of calcium channels in the development and/or maturation of synapses. The Ca(V1.4(α(1F knockout mouse is a unique model to study the role of calcium channels in photoreceptor synapse formation. It features abnormal ribbon synapses and aberrant cone morphology. We investigated the expression and targeting of several key elements of ribbon synapses and analyzed the cone morphology in the Ca(V1.4(α(1F knockout retina. Our data demonstrate that most abnormalities occur after eye opening. Indeed, scaffolding proteins such as Bassoon and RIM2 are properly targeted at first, but their expression and localization are not maintained in adulthood. This indicates that either calcium or the Ca(V1.4 channel, or both are necessary for the maintenance of their normal expression and distribution in photoreceptors. Other proteins, such as Veli3 and PSD-95, also display abnormal expression in rods prior to eye opening. Conversely, vesicle related proteins appear normal. Our data demonstrate that the Ca(V1.4 channel is important for maintaining scaffolding proteins in the ribbon synapse but less vital for proteins related to vesicular release. This study also confirms that in adult retinae, cones show developmental features such as sprouting and synaptogenesis. Overall we present evidence that in the absence of the Ca(V1.4 channel, photoreceptor synapses remain immature and are unable to stabilize.

  2. Ciliary photoreceptors in the cerebral eyes of a protostome larva

    Directory of Open Access Journals (Sweden)

    Passamaneck Yale J

    2011-03-01

    Full Text Available Abstract Background Eyes in bilaterian metazoans have been described as being composed of either ciliary or rhabdomeric photoreceptors. Phylogenetic distribution, as well as distinct morphologies and characteristic deployment of different photopigments (ciliary vs. rhabdomeric opsins and transduction pathways argue for the co-existence of both of these two photoreceptor types in the last common bilaterian ancestor. Both receptor types exist throughout the Bilateria, but only vertebrates are thought to use ciliary photoreceptors for directional light detection in cerebral eyes, while all other invertebrate bilaterians studied utilize rhabdomeric photoreceptors for this purpose. In protostomes, ciliary photoreceptors that express c-opsin have been described only from a non-visual deep-brain photoreceptor. Their homology with vertebrate rods and cones of the human eye has been hypothesized to represent a unique functional transition from non-visual to visual roles in the vertebrate lineage. Results To test the hypothesis that protostome cerebral eyes employ exclusively rhabdomeric photoreceptors, we investigated the ultrastructure of the larval eyes in the brachiopod Terebratalia transversa. We show that these pigment-cup eyes consist of a lens cell and a shading pigment cell, both of which are putative photoreceptors, deploying a modified, enlarged cilium for light perception, and have axonal connections to the larval brain. Our investigation of the gene expression patterns of c-opsin, Pax6 and otx in these eyes confirms that the larval eye spots of brachiopods are cerebral eyes that deploy ciliary type photoreceptors for directional light detection. Interestingly, c-opsin is also expressed during early embryogenesis in all potential apical neural cells, becoming restricted to the anterior neuroectoderm, before expression is initiated in the photoreceptor cells of the eyes. Coincident with the expression of c-opsin in the presumptive neuroectoderm

  3. Do male and female cowbirds see their world differently? Implications for sex differences in the sensory system of an avian brood parasite.

    Directory of Open Access Journals (Sweden)

    Esteban Fernández-Juricic

    Full Text Available BACKGROUND: Male and female avian brood parasites are subject to different selection pressures: males compete for mates but do not provide parental care or territories and only females locate hosts to lay eggs. This sex difference may affect brain architecture in some avian brood parasites, but relatively little is known about their sensory systems and behaviors used to obtain sensory information. Our goal was to study the visual resolution and visual information gathering behavior (i.e., scanning of brown-headed cowbirds. METHODOLOGY/PRINCIPAL FINDINGS: We measured the density of single cone photoreceptors, associated with chromatic vision, and double cone photoreceptors, associated with motion detection and achromatic vision. We also measured head movement rates, as indicators of visual information gathering behavior, when exposed to an object. We found that females had significantly lower density of single and double cones than males around the fovea and in the periphery of the retina. Additionally, females had significantly higher head-movement rates than males. CONCLUSIONS: Overall, we suggest that female cowbirds have lower chromatic and achromatic visual resolution than males (without sex differences in visual contrast perception. Females might compensate for the lower visual resolution by gazing alternatively with both foveae in quicker succession than males, increasing their head movement rates. However, other physiological factors may have influenced the behavioral differences observed. Our results bring up relevant questions about the sensory basis of sex differences in behavior. One possibility is that female and male cowbirds differentially allocate costly sensory resources, as a recent study found that females actually have greater auditory resolution than males.

  4. Regulation of photoreceptor gap junction phosphorylation by adenosine in zebrafish retina.

    Science.gov (United States)

    Li, Hongyan; Chuang, Alice Z; O'Brien, John

    2014-05-01

    Electrical coupling of photoreceptors through gap junctions suppresses voltage noise, routes rod signals into cone pathways, expands the dynamic range of rod photoreceptors in high scotopic and mesopic illumination, and improves detection of contrast and small stimuli. In essentially all vertebrates, connexin 35/36 (gene homologs Cx36 in mammals, Cx35 in other vertebrates) is the major gap junction protein observed in photoreceptors, mediating rod-cone, cone-cone, and possibly rod-rod communication. Photoreceptor coupling is dynamically controlled by the day/night cycle and light/dark adaptation, and is directly correlated with phosphorylation of Cx35/36 at two sites, serine110 and serine 276/293 (homologous sites in teleost fish and mammals, respectively). Activity of protein kinase A (PKA) plays a key role during this process. Previous studies have shown that activation of dopamine D4 receptors on photoreceptors inhibits adenylyl cyclase, down-regulates cAMP and PKA activity, and leads to photoreceptor uncoupling, imposing the daytime/light condition. In this study, we explored the role of adenosine, a nighttime signal with a high extracellular concentration at night and a low concentration in the day, in regulating photoreceptor coupling by examining photoreceptor Cx35 phosphorylation in zebrafish retina. Adenosine enhanced photoreceptor Cx35 phosphorylation in daytime, but with a complex dose-response curve. Selective pharmacological manipulations revealed that adenosine A2a receptors provide a potent positive drive to phosphorylate photoreceptor Cx35 under the influence of endogenous adenosine at night. A2a receptors can be activated in the daytime as well by micromolar exogenous adenosine. However, the higher affinity adenosine A1 receptors are also present and have an antagonistic though less potent effect. Thus, the nighttime/darkness signal adenosine provides a net positive drive on Cx35 phosphorylation at night, working in opposition to dopamine to

  5. Fine structure of the retinal photoreceptors of the great horned owl (Bubo virginianus)

    OpenAIRE

    Braekevelt, Charlie R.

    1993-01-01

    The retinal photoreceptors of the great horned owl (Bubo virginianus) consist of rods, single cones and unequal double cones present in a ratio of about 30:1:2. In the light-adapted state the rods are stout cells which are not felt to undergo retinomotor movements. The rod outer segment consists of a stack of scalloped membranous discs enclosed by the cell membrane. The rod inner segment shows an ellipsoid of mitochondria and a wealth of rough endoplasmic r...

  6. Cone rod dystrophies

    Directory of Open Access Journals (Sweden)

    Hamel Christian P

    2007-02-01

    Full Text Available Abstract Cone rod dystrophies (CRDs (prevalence 1/40,000 are inherited retinal dystrophies that belong to the group of pigmentary retinopathies. CRDs are characterized by retinal pigment deposits visible on fundus examination, predominantly localized to the macular region. In contrast to typical retinitis pigmentosa (RP, also called the rod cone dystrophies (RCDs resulting from the primary loss in rod photoreceptors and later followed by the secondary loss in cone photoreceptors, CRDs reflect the opposite sequence of events. CRD is characterized by primary cone involvement, or, sometimes, by concomitant loss of both cones and rods that explains the predominant symptoms of CRDs: decreased visual acuity, color vision defects, photoaversion and decreased sensitivity in the central visual field, later followed by progressive loss in peripheral vision and night blindness. The clinical course of CRDs is generally more severe and rapid than that of RCDs, leading to earlier legal blindness and disability. At end stage, however, CRDs do not differ from RCDs. CRDs are most frequently non syndromic, but they may also be part of several syndromes, such as Bardet Biedl syndrome and Spinocerebellar Ataxia Type 7 (SCA7. Non syndromic CRDs are genetically heterogeneous (ten cloned genes and three loci have been identified so far. The four major causative genes involved in the pathogenesis of CRDs are ABCA4 (which causes Stargardt disease and also 30 to 60% of autosomal recessive CRDs, CRX and GUCY2D (which are responsible for many reported cases of autosomal dominant CRDs, and RPGR (which causes about 2/3 of X-linked RP and also an undetermined percentage of X-linked CRDs. It is likely that highly deleterious mutations in genes that otherwise cause RP or macular dystrophy may also lead to CRDs. The diagnosis of CRDs is based on clinical history, fundus examination and electroretinogram. Molecular diagnosis can be made for some genes, genetic counseling is

  7. Quantification of photoreceptor layer thickness in different macular pathologies using ultrahigh-resolution optical coherence tomography

    Science.gov (United States)

    Drexler, Wolfgang; Hermann, Boris; Unterhuber, Angelika; Sattmann, Harald; Wirtitsch, Matthias; Stur, Michael; Scholda, Christoph; Ergun, Erdem; Anger, Elisabeth; Ko, Tony H.; Schubert, Christian; Ahnelt, Peter K.; Fujimoto, James G.; Fercher, Adolf F.

    2004-07-01

    In vivo ultrahigh resolution ophthalmic OCT has been performed in more than 300 eyes of 200 patients with several retinal pathologies, demonstrating unprecedented visualization of all major intraretinal layers, in particular the photoreceptor layer. Visualization as well as quantification of the inner and outer segment of the photoreceptor layer especially in the foveal region has been acvhieved. In normal subjects the photoreceptor layer thickness in the center of the fovea is about of 90 μm, approximately equally distributed to the inner and the outer photoreceptor segment. In the parafoveal region this thickness is reduced to ~50 μm (~30 μm for the inner and ~20 μm for the outer segment). This is in good agreement with well known increase of cone outer segments in the central foveal region. Photoreceptor layer impairment in different macular pathologies like macular hole, central serous chorioretinopathy, age related macular degeneration, foveomacular dystrophies, Stargardt dystrophy as well as retinitis pigmentosa has been investigated. Photoreceptor layer loss significantly correlated with visual acuity (R2 = 0.6, p dystrophy. Visualization and quantification of photoreceptor inner and outer segment using ultrahigh resolution OCT has the potential to improve early ophthalmic diagnosis, contributes to a better understanding of pathogenesis of retinal diseases as well as might have impact in the development and monitoring of novel therapy approaches.

  8. Avian influenza

    Science.gov (United States)

    Bird flu; H5N1; H5N2; H5N8; H7N9; Avian influenza A (HPAI) H5 ... The first avian influenza in humans was reported in Hong Kong in 1997. It was called avian influenza (H5N1). The outbreak was linked ...

  9. Photoreceptor counting and montaging of en-face retinal images from an adaptive optics fundus camera

    Science.gov (United States)

    Xue, Bai; Choi, Stacey S.; Doble, Nathan; Werner, John S.

    2007-05-01

    A fast and efficient method for quantifying photoreceptor density in images obtained with an en-face flood-illuminated adaptive optics (AO) imaging system is described. To improve accuracy of cone counting, en-face images are analyzed over extended areas. This is achieved with two separate semiautomated algorithms: (1) a montaging algorithm that joins retinal images with overlapping common features without edge effects and (2) a cone density measurement algorithm that counts the individual cones in the montaged image. The accuracy of the cone density measurement algorithm is high, with >97% agreement for a simulated retinal image (of known density, with low contrast) and for AO images from normal eyes when compared with previously reported histological data. Our algorithms do not require spatial regularity in cone packing and are, therefore, useful for counting cones in diseased retinas, as demonstrated for eyes with Stargardt's macular dystrophy and retinitis pigmentosa.

  10. Fly Photoreceptors Encode Phase Congruency

    Science.gov (United States)

    Friederich, Uwe; Billings, Stephen A.; Hardie, Roger C.; Juusola, Mikko; Coca, Daniel

    2016-01-01

    More than five decades ago it was postulated that sensory neurons detect and selectively enhance behaviourally relevant features of natural signals. Although we now know that sensory neurons are tuned to efficiently encode natural stimuli, until now it was not clear what statistical features of the stimuli they encode and how. Here we reverse-engineer the neural code of Drosophila photoreceptors and show for the first time that photoreceptors exploit nonlinear dynamics to selectively enhance and encode phase-related features of temporal stimuli, such as local phase congruency, which are invariant to changes in illumination and contrast. We demonstrate that to mitigate for the inherent sensitivity to noise of the local phase congruency measure, the nonlinear coding mechanisms of the fly photoreceptors are tuned to suppress random phase signals, which explains why photoreceptor responses to naturalistic stimuli are significantly different from their responses to white noise stimuli. PMID:27336733

  11. Photoreceptor topography and spectral sensitivity in the common brushtail possum (Trichosurus vulpecula).

    Science.gov (United States)

    Vlahos, Lisa M; Knott, Ben; Valter, Krisztina; Hemmi, Jan M

    2014-10-15

    Marsupials are believed to be the only non-primate mammals with both trichromatic and dichromatic color vision. The diversity of color vision systems present in marsupials remains mostly unexplored. Marsupials occupy a diverse range of habitats, which may have led to considerable variation in the presence, density, distribution, and spectral sensitivity of retinal photoreceptors. In this study we analyzed the distribution of photoreceptors in the common brushtail possum (Trichosurus vulpecula). Immunohistochemistry in wholemounts revealed three cone subpopulations recognized within two spectrally distinct cone classes. Long-wavelength sensitive (LWS) single cones were the largest cone subgroup (67-86%), and formed a weak horizontal visual streak (peak density 2,106 ± 435/mm2) across the central retina. LWS double cones were strongly concentrated ventrally (569 ± 66/mm2), and created a "negative" visual streak (134 ± 45/mm2) in the central retina. The strong regionalization between LWS cone topographies suggests differing visual functions. Short-wavelength sensitive (SWS) cones were present in much lower densities (3-10%), mostly located ventrally (179 ± 101/mm2). A minority population of cones (0-2.4%) remained unlabeled by both SWS- and LWS-specific antibodies, and may represent another cone population. Microspectrophotometry of LWS cone and rod visual pigments shows peak spectral sensitivities at 544 nm and 500 nm, respectively. Cone to ganglion cell convergences remain low and constant across the retina, thereby maintaining good visual acuity, but poor contrast sensitivity during photopic vision. Given that brushtail possums are so strongly nocturnal, we hypothesize that their acuity is set by the scotopic visual system, and have minimized the number of cones necessary to serve the ganglion cells for photopic vision. PMID:24737644

  12. In-vivo imaging of the photoreceptor mosaic in retinal dystrophies and correlations with visual function

    Energy Technology Data Exchange (ETDEWEB)

    Choi, S; Doble, N; Hardy, J; Jones, S; Keltner, J; Olivier, S; Werner, J S

    2005-10-26

    To relate in-vivo microscopic retinal changes to visual function assessed with clinical tests in patients with various forms of retinal dystrophies. The UC Davis Adaptive Optics (AO) Fundus Camera was used to acquire in-vivo retinal images at the cellular level. Visual function tests, consisting of visual field analysis, multifocal electroretinography (mfERG), contrast sensitivity and color vision measures, were performed on all subjects. Five patients with different forms of retinal dystrophies and three control subjects were recruited. Cone densities were quantified for all retinal images. In all images of diseased retinas, there were extensive areas of dark space between groups of photoreceptors, where no cone photoreceptors were evident. These irregular features were not seen in healthy retinas, but were characteristic features in fundi with retinal dystrophies. There was a correlation between functional vision loss and the extent to which the irregularities occurred in retinal images. Cone densities were found to decrease with an associated decrease in retinal function. AO fundus photography is a reliable technique for assessing and quantifying the changes in the photoreceptor layer as disease progresses. Furthermore, this technique can be useful in cases where visual function tests give borderline or ambiguous results, as it allows visualization of individual photoreceptors.

  13. Adaptation in Cones: A General Model

    OpenAIRE

    Dawis, Stevan M.; Purple, Richard L.

    1982-01-01

    Three features appear to characterize steady-state light adaptation in vertebrate cone photoreceptors: (a) the shape of the “log intensity-response” curve at different levels of adaptation is the same, the only change with adaptation is in the position of the point on the curve about which the cones operate; (b) at high adapting intensities the operating point becomes fixed in position; (c) this fixed position is at the steepest point of the log intensity-response curve. These three features ...

  14. Special characteristics of the transcription and splicing machinery in photoreceptor cells of the mammalian retina.

    Science.gov (United States)

    Derlig, Kristin; Giessl, Andreas; Brandstätter, Johann Helmut; Enz, Ralf; Dahlhaus, Regina

    2015-11-01

    Chromatin organization and the management of transcription and splicing are fundamental to the correct functioning of every cell but, in particular, for highly active cells such as photoreceptors, the sensory neurons of the retina. Rod photoreceptor cells of nocturnal animals have recently been shown to have an inverted chromatin architecture compared with rod photoreceptor cells of diurnal animals. The heterochromatin is concentrated in the center of the nucleus, whereas the genetically active euchromatin is positioned close to the nuclear membrane. This unique chromatin architecture suggests that the transcription and splicing machinery is also subject to specific adaptations in these cells. Recently, we described the protein Simiate, which is enriched in nuclear speckles and seems to be involved in transcription and splicing processes. Here, we examine the distribution of Simiate and nuclear speckles in neurons of mouse retinae. In retinal neurons of the inner nuclear and ganglion cell layer, Simiate is concentrated in a clustered pattern in the nuclear interior, whereas in rod and cone photoreceptor cells, Simiate is present at the nuclear periphery. Further staining with markers for the transcription and splicing machinery has confirmed the localization of nuclear speckle components at the periphery. Comparing the distribution of nuclear speckles in retinae of the nocturnal mouse with the diurnal degu, we found no differences in the arrangement of the transcription and splicing machinery in their photoreceptor cells, thus suggesting that the organization of these machineries is not related to the animal's lifestyle but rather represents a general characteristic of photoreceptor organization and function. PMID:26013685

  15. Genetic Dissection of Dual Roles for the Transcription Factor six7 in Photoreceptor Development and Patterning in Zebrafish.

    Science.gov (United States)

    Sotolongo-Lopez, Mailin; Alvarez-Delfin, Karen; Saade, Carole J; Vera, Daniel L; Fadool, James M

    2016-04-01

    The visual system of a particular species is highly adapted to convey detailed ecological and behavioral information essential for survival. The consequences of structural mutations of opsins upon spectral sensitivity and environmental adaptation have been studied in great detail, but lacking is knowledge of the potential influence of alterations in gene regulatory networks upon the diversity of cone subtypes and the variation in the ratio of rods and cones observed in numerous diurnal and nocturnal species. Exploiting photoreceptor patterning in cone-dominated zebrafish, we uncovered two independent mechanisms by which the sine oculis homeobox homolog 7 (six7) regulates photoreceptor development. In a genetic screen, we isolated the lots-of-rods-junior (ljrp23ahub) mutation that resulted in an increased number and uniform distribution of rods in otherwise normal appearing larvae. Sequence analysis, genome editing using TALENs and knockdown strategies confirm ljrp23ahub as a hypomorphic allele of six7, a teleost orthologue of six3, with known roles in forebrain patterning and expression of opsins. Based on the lack of predicted protein-coding changes and a deletion of a conserved element upstream of the transcription start site, a cis-regulatory mutation is proposed as the basis of the reduced expression of six7 in ljrp23ahub. Comparison of the phenotypes of the hypomorphic and knock-out alleles provides evidence of two independent roles in photoreceptor development. EdU and PH3 labeling show that the increase in rod number is associated with extended mitosis of photoreceptor progenitors, and TUNEL suggests that the lack of green-sensitive cones is the result of cell death of the cone precursor. These data add six7 to the small but growing list of essential genes for specification and patterning of photoreceptors in non-mammalian vertebrates, and highlight alterations in transcriptional regulation as a potential source of photoreceptor variation across species

  16. Three distinct roles for notch in Drosophila R7 photoreceptor specification.

    Directory of Open Access Journals (Sweden)

    Andrew Tomlinson

    2011-08-01

    Full Text Available Receptor tyrosine kinases (RTKs and Notch (N proteins are different types of transmembrane receptors that transduce extracellular signals and control cell fate. Here we examine cell fate specification in the Drosophila retina and ask how N acts together with the RTKs Sevenless (Sev and the EGF receptor (DER to specify the R7 photoreceptor. The retina is composed of many hundred ommatidia, each of which grows by recruiting surrounding, undifferentiated cells and directing them to particular fates. The R7 photoreceptor derives from a cohort of three cells that are incorporated together following specification of the R2-R5 and R8 photoreceptors. Two cells of the cohort are specified as the R1/6 photoreceptor type by DER activation. These cells then activate N in the third cell (the R7 precursor. By manipulation of N and RTK signaling in diverse combinations we establish three roles for N in specifying the R7 fate. The first role is to impose a block to photoreceptor differentiation; a block that DER activation cannot overcome. The second role, paradoxically, is to negate the first; Notch activation up-regulates Sev expression, enabling the presumptive R7 cell to receive an RTK signal from R8 that can override the block. The third role is to specify the cell as an R7 rather than an R1/6 once RTK signaling has specified the cells as a photoreceptor. We speculate why N acts both to block and to facilitate photoreceptor differentiation, and provide a model for how N and RTK signaling act combinatorially to specify the R1/6 and R7 photoreceptors as well as the surrounding non-neuronal cone cells.

  17. Combinatorial Regulation of Photoreceptor Differentiation Factor, Neural Retina Leucine Zipper Gene Nrl, Revealed by in Vivo Promoter Analysis*

    OpenAIRE

    Kautzmann, Marie-Audrey I.; Kim, Douglas S; Felder-Schmittbuhl, Marie-Paule; Swaroop, Anand

    2011-01-01

    Development and homeostasis require stringent spatiotemporal control of gene expression patterns that are established, to a large extent, by combinatorial action of transcription regulatory proteins. The bZIP transcription factor NRL (neural retina leucine zipper) is critical for rod versus cone photoreceptor cell fate choice during retinal development and acts as a molecular switch to produce rods from postmitotic precursors. Loss of Nrl in mouse leads to a cone-only retina, whereas ectopic ...

  18. Light and electron microscopic studies on the pigmented epithelium and photoreceptors of the retina of common buzzard (Buteo buteo).

    Science.gov (United States)

    El-Beltagy, Abd El-Fattah B M

    2015-02-01

    The current study is essentially carried out to reveal the histological and ultra-structural details of the retinal pigmented epithelium (RPE) and photoreceptors cell layers of a common buzzard (Buteo buteo). The recorded results revealed that the neural retina of common buzzard consisted of seven distinct cell layers. The inner nuclear layer was markedly revealed as the thickest one among these layers. A highly melanized RPE was recorded in between the choroid and neural retina. Histologically, the RPE was represented by a single layer of cuboidal epithelial cells with centrally located nucleus. Ultrastructurally, the RPE cells showed numerous melanosomes, mitochondria, phagosomes, myeloid bodies, smooth endoplasmic reticulum (SER), but very rare rough endoplasmic reticulum (RER). The photoreceptor cell layer was represented by three categories of photoreceptor cells: few single rods, numerous single and double cones. Each double cone consisted of a short accessory cone and a long principle cone. The photoreceptor outer segment consisted of bi-membranous discs that are enclosed by outer membrane. Moreover, the inner segment of rods consisted of an ellipsoid and an inner hyperboloid. The hyperboloid was rich with RER, polysomes, Golgi apparatus and autophagic vacuoles. Furthermore, the inner segment of single cone and accessory cone consisted of an ellipsoid, paraboloid and myoid regions, while, the inner segment of principle cone lacked the paraboloid regions. At the proximal end of each inner segment for all types of cones, there was a large heterogeneous oil droplet. The paraboloid region was markedly rich with glycogen granules. The myoid region exhibited the same organelles but with little glycogen granules when compared with hyperboloid. PMID:25541273

  19. Single-photon sensitivity of lamprey rods with cone-like outer segments

    OpenAIRE

    Morshedian, A; Fain, GL

    2015-01-01

    © 2015 Elsevier Ltd All rights reserved. Most vertebrates have a duplex retina containing rods for dim light vision and cones for bright lights and color detection. Photoreceptors like cones are present in many invertebrate phyla as well as in chordata, and rods evolved from cones [1, 2], but the sequence of events is not well understood. Since duplex retinas are present in both agnatha and gnathostomata, which diverged more than 400 million years ago, some properties of ancestral rods may be...

  20. AAV Vectors for FRET-Based Analysis of Protein-Protein Interactions in Photoreceptor Outer Segments

    Science.gov (United States)

    Becirovic, Elvir; Böhm, Sybille; Nguyen, Ong N. P.; Riedmayr, Lisa M.; Hammelmann, Verena; Schön, Christian; Butz, Elisabeth S.; Wahl-Schott, Christian; Biel, Martin; Michalakis, Stylianos

    2016-01-01

    Fluorescence resonance energy transfer (FRET) is a powerful method for the detection and quantification of stationary and dynamic protein-protein interactions. Technical limitations have hampered systematic in vivo FRET experiments to study protein-protein interactions in their native environment. Here, we describe a rapid and robust protocol that combines adeno-associated virus (AAV) vector-mediated in vivo delivery of genetically encoded FRET partners with ex vivo FRET measurements. The method was established on acutely isolated outer segments of murine rod and cone photoreceptors and relies on the high co-transduction efficiency of retinal photoreceptors by co-delivered AAV vectors. The procedure can be used for the systematic analysis of protein-protein interactions of wild type or mutant outer segment proteins in their native environment. Conclusively, our protocol can help to characterize the physiological and pathophysiological relevance of photoreceptor specific proteins and, in principle, should also be transferable to other cell types. PMID:27516733

  1. In vivo optical imaging of physiological responses to photostimulation in human photoreceptors

    CERN Document Server

    Hillmann, Dierck; Pfäffle, Clara; Sudkamp, Helge; Franke, Gesa; Hüttmann, Gereon

    2016-01-01

    Non-invasive functional imaging of molecular and cellular processes of vision is expected to have immense impact on research and clinical diagnostics. Although suitable intrinsic optical signals (IOS) have been observed ex vivo and in immobilized animals in vivo, it was so far not possible to obtain convincing IOS of photoreceptor activity in humans in vivo. Here, we observed spatially and temporally clearly resolved changes in the optical path length of the photoreceptor outer segment as response to an optical stimulus in living human. To obtain these changes, we evaluated phase data of a parallelized and computationally aberration-corrected optical coherence tomography (OCT) system. The non-invasive detection of optical path length changes shows the neuronal photoreceptor activity of single cones in living human retina, and, more importantly, it provides a new diagnostic option in ophthalmology and neurology and could give new insights into visual phototransduction in humans.

  2. Estimating photoreceptor excitations from spectral outputs of a personal light exposure measurement device.

    Science.gov (United States)

    Cao, Dingcai; Barrionuevo, Pablo A

    2015-03-01

    The intrinsic circadian clock requires photoentrainment to synchronize the 24-hour solar day. Therefore, light stimulation is an important component of chronobiological research. Currently, the chronobiological research field overwhelmingly uses photopic illuminance that is based on the luminous efficiency function, V(λ), to quantify light levels. However, recent discovery of intrinsically photosensitive retinal ganglion cells (ipRGCs), which are activated by self-contained melanopsin photopigment and also by inputs from rods and cones, makes light specification using a one-dimensional unit inadequate. Since the current understanding of how different photoreceptor inputs contribute to the circadian system through ipRGCs is limited, it is recommended to specify light in terms of the excitations of five photoreceptors (S-, M-, L-cones, rods and ipRGCs; Lucas et al., 2014). In the current study, we assessed whether the spectral outputs from a commercially available spectral watch (i.e. Actiwatch Spectrum) could be used to estimate photoreceptor excitations. Based on the color sensor spectral sensitivity functions from a previously published work, as well as from our measurements, we computed spectral outputs in the long-wavelength range (R), middle-wavelength range (G), short-wavelength range (B) and broadband range (W) under 52 CIE illuminants (25 daylight illuminants, 27 fluorescent lights). We also computed the photoreceptor excitations for each illuminant using human photoreceptor spectral sensitivity functions. Linear regression analyses indicated that the Actiwatch spectral outputs could predict photoreceptor excitations reliably, under the assumption of linear responses of the Actiwatch color sensors. In addition, R, G, B outputs could classify illuminant types (fluorescent versus daylight illuminants) satisfactorily. However, the assessment of actual Actiwatch recording under several testing light sources showed that the spectral outputs were subject to

  3. Avian influenza

    Science.gov (United States)

    ... of avian influenza A in Asia, Africa, Europe, Indonesia, Vietnam, the Pacific, and the near East. Hundreds ... to detect abnormal breath sounds) Chest x-ray Culture from the nose or throat A method or ...

  4. Avian Flu

    Energy Technology Data Exchange (ETDEWEB)

    Eckburg, Paul

    2006-11-06

    Since 2003, a severe form of H5N1 avian influenza has rapidly spread throughout Asia and Europe, infecting over 200 humans in 10 countries. The spread of H5N1 virus from person-to-person has been rare, thus preventing the emergence of a widespread pandemic. However, this ongoing epidemic continues to pose an important public health threat. Avian flu and its pandemic potential in humans will be discussed.

  5. Avian Flu

    International Nuclear Information System (INIS)

    Since 2003, a severe form of H5N1 avian influenza has rapidly spread throughout Asia and Europe, infecting over 200 humans in 10 countries. The spread of H5N1 virus from person-to-person has been rare, thus preventing the emergence of a widespread pandemic. However, this ongoing epidemic continues to pose an important public health threat. Avian flu and its pandemic potential in humans will be discussed.

  6. Avian Research

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    <正>Aims and Scope Avian Research is an open access,peer-reviewed journal publishing high quality research and review articles on all aspects of ornithology from all over the world.It aims to report the latest and most significant progress in ornithology and to encourage exchange of ideas among international ornithologists.As an Open Access journal,Avian Research provides a unique opportunity to publish high quality contents that will be internationally accessible to any reader at no cost.

  7. Rod photoreceptors drive circadian photoentrainment across a wide range of light intensities

    OpenAIRE

    Altimus, C. M.; Güler, A. D.; N.M. Alam; Arman, A.C.; Prusky, G.T.; Sampath, A.P.; Hattar, S.

    2010-01-01

    In mammals, synchronization of the circadian pacemaker in the hypothalamus is achieved through direct input from the eyes conveyed by intrinsically photosensitive retinal ganglion cells (ipRGCs). Circadian photoentrainment can be maintained by rod and cone photoreceptors, but their functional contributions and their retinal circuits that impinge on ipRGCs are not well understood. We demonstrate in genetic mouse models lacking functional rods, or where rods are the only functional photorecepto...

  8. Retinal circadian clocks and non-visual photoreceptors: light input to the circadian system.

    OpenAIRE

    Ouria Dkhissi-Benyahya

    2013-01-01

    The mammalian retina contains an endogenous pacemaker that regulates retinal physiology and adjusts daily the temporal phase of the central circadian timing system with environmental time. This entrainment process involves rods, cones and melanopsin-expressing retinal ganglion cells. In contrast with non mammalian retinas, in which the clock has been identified in photoreceptors, the location of the retinal circadian clock in mammals is still controversial. In addition, the impact of specific...

  9. Simulating human photoreceptor optics using a liquid-filled photonic crystal fiber

    OpenAIRE

    Rativa, Diego; Vohnsen, Brian

    2011-01-01

    We introduce a liquid-filled photonic crystal fiber to simulate a retinal cone photoreceptor mosaic and the directionality selective mechanism broadly known as the Stiles-Crawford effect. Experimental measurements are realized across the visible spectrum to study waveguide coupling and directionality at different managed waveguide parameters. The crystal fiber method is a hybrid tool between theory and a real biological sample and a valuable addition as a retina model for real eye simulations.

  10. The locations of mitochondria in mammalian photoreceptors: relation to retinal vasculature.

    Science.gov (United States)

    Stone, Jonathan; van Driel, Diana; Valter, Krisztina; Rees, Sandra; Provis, Jan

    2008-01-16

    Adult mammalian photoreceptors are elongated cells, and their mitochondria are sequestered to the ends of the cell, to the inner segments and (in some species) to axon terminals in the outer plexiform layer (OPL). We hypothesised that mitochondria migrate to these locations towards sources of oxygen, from the choroid and (in some species) from the deep capillaries of the retinal circulation. Six mammalian species were surveyed, using electron and light microscopy, including immunohistochemistry for the mitochondrial enzyme cytochrome oxidase (CO). In all 6 species, mitochondria were absent from photoreceptor somas and were numerous in inner segments. Mitochondria were prominent in axon terminals in 3 species (mouse, rat, human) with a retinal circulation and were absent from those terminals in 3 species (wallaby, rat, guinea pig) with avascular retinas. Further, in a human developmental series, it was evident that mitochondria migrate within rods and cones, towards and eventually past the outer limiting membrane (OLM), into the inner segment. In Müller and RPE cells also, mitochondria concentrated at the external surface of the cells. Neurones located in the inner layers of avascular retinas have mitochondria, but their expression of CO is low. Mitochondrial locations in photoreceptors, Müller and RPE cells are economically explained as the result of migration within the cell towards sources of oxygen. In photoreceptors, this migration results in a separation of mitochondria from the nuclear genome; this separation may be a factor in the vulnerability of photoreceptors to mutations, toxins and environmental stresses, which other retinal neurones survive. PMID:18048005

  11. Action spectra and adaptation properties of carp photoreceptors.

    Science.gov (United States)

    Witkovsky, P; Nelson, J; Ripps, H

    1973-04-01

    The mass photoreceptor response of the isolated carp retina was studied after immersing the tissue in aspartate-Ringer solution. Two electro-retinogram components were isolated by differential depth recording: a fast cornea-negative wave, arising in the receptor layer, and a slow, cornea-negative wave arising at some level proximal to the photoreceptors. Only the fast component was investigated further. In complete dark adaptation, its action spectrum peaked near 540 nm and indicated input from both porphyropsin-containing rods (lambda(max) approximately 525 nm) and cones with longer wavelength sensitivity. Under photopic conditions a broad action spectrum, lambda(max) approximately 580 nm was seen. In the presence of chromatic backgrounds, the photopic curve could be fractionated into three components whose action spectra agreed reasonably well with the spectral characteristics of blue, green, and red cone pigments of the goldfish. In parallel studies, the carp rod pigment was studied in situ by transmission densitometry. The reduction in optical density after a full bleach averaged 0.28 at its lambda(max) 525 nm. In the isolated retina no regeneration of rod pigment occurred within 2 h after bleaching. The bleaching power of background fields used in adaptation experiments was determined directly. Both rods and cones generated increment threshold functions with slopes of +1 on log-log coordinates over a 3-4 log range of background intensities. Background fields which bleached less than 0.5% rod pigment nevertheless diminished photoreceptor sensitivity. The degree and rate of recovery of receptor sensitivity after exposure to a background field was a function of the total flux (I x t) of the field. Rod saturation, i.e. the abolition of rod voltages, occurred after approximately 12% of rod pigment was bleached. In light-adapted retinas bathed in normal Ringer solution, a small test flash elicited a larger response in the presence of an annular background field than

  12. Microspectrophotometric evidence for cone monochromacy in sharks

    Science.gov (United States)

    Hart, Nathan Scott; Theiss, Susan Michelle; Harahush, Blake Kristin; Collin, Shaun Patrick

    2011-03-01

    Sharks are apex predators, and their evolutionary success is in part due to an impressive array of sensory systems, including vision. The eyes of sharks are well developed and function over a wide range of light levels. However, whilst close relatives of the sharks—the rays and chimaeras—are known to have the potential for colour vision, an evolutionary trait thought to provide distinct survival advantages, evidence for colour vision in sharks remains equivocal. Using single-receptor microspectrophotometry, we measured the absorbance spectra of visual pigments located in the retinal photoreceptors of 17 species of shark. We show that, while the spectral tuning of the rod (wavelength of maximum absorbance, λmax 484-518 nm) and cone (λmax 532-561 nm) visual pigments varies between species, each shark has only a single long-wavelength-sensitive cone type. This suggests that sharks may be cone monochromats and, therefore, potentially colour blind. Whilst cone monochromacy on land is rare, it may be a common strategy in the marine environment: many aquatic mammals (whales, dolphins and seals) also possess only a single, green-sensitive cone type. It appears that both sharks and marine mammals may have arrived at the same visual design by convergent evolution. The spectral tuning of the rod and cone pigments of sharks is also discussed in relation to their visual ecology.

  13. Microspectrophotometric evidence for cone monochromacy in sharks.

    Science.gov (United States)

    Hart, Nathan Scott; Theiss, Susan Michelle; Harahush, Blake Kristin; Collin, Shaun Patrick

    2011-03-01

    Sharks are apex predators, and their evolutionary success is in part due to an impressive array of sensory systems, including vision. The eyes of sharks are well developed and function over a wide range of light levels. However, whilst close relatives of the sharks-the rays and chimaeras-are known to have the potential for colour vision, an evolutionary trait thought to provide distinct survival advantages, evidence for colour vision in sharks remains equivocal. Using single-receptor microspectrophotometry, we measured the absorbance spectra of visual pigments located in the retinal photoreceptors of 17 species of shark. We show that, while the spectral tuning of the rod (wavelength of maximum absorbance, λ(max) 484-518 nm) and cone (λ(max) 532-561 nm) visual pigments varies between species, each shark has only a single long-wavelength-sensitive cone type. This suggests that sharks may be cone monochromats and, therefore, potentially colour blind. Whilst cone monochromacy on land is rare, it may be a common strategy in the marine environment: many aquatic mammals (whales, dolphins and seals) also possess only a single, green-sensitive cone type. It appears that both sharks and marine mammals may have arrived at the same visual design by convergent evolution. The spectral tuning of the rod and cone pigments of sharks is also discussed in relation to their visual ecology. PMID:21212930

  14. Avian Influenza

    OpenAIRE

    Tsung-Zu Wu; Li-Min Huang

    2005-01-01

    Influenza is an old disease but remains vital nowadays. Three types of influenza viruses,namely A, B, C, have been identified; among them influenza A virus has pandemic potential.The first outbreak of human illness due to avian influenza virus (H5N1) occurred in1997 in Hong Kong with a mortality of 30%. The most recent outbreak of the avian influenzaepidemic has been going on in Asian countries since 2003. As of March 2005, 44 incidentalhuman infections and 32 deaths have been documented. Hum...

  15. Damage of photoreceptor-derived cells in culture induced by light emitting diode-derived blue light

    OpenAIRE

    Kuse, Yoshiki; Ogawa, Kenjiro; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Hara, Hideaki

    2014-01-01

    Our eyes are increasingly exposed to light from the emitting diode (LED) light of video display terminals (VDT) which contain much blue light. VDTs are equipped with televisions, personal computers, and smart phones. The present study aims to clarify the mechanism underlying blue LED light-induced photoreceptor cell damage. Murine cone photoreceptor-derived cells (661 W) were exposed to blue, white, or green LED light (0.38 mW/cm2). In the present study, blue LED light increased reactive oxyg...

  16. Avian Research

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>Aims and Scope Avian Research is an open access,peer-reviewed journal publishing high quality research and review articles on all aspects of ornithology from all over the world.It aims to report the latest and most significant progress in ornithology and to encourage exchange of ideas among international ornithologists.As an Open Access journal,

  17. Avian Research

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    <正>Aims and Scope Avian Research is an open access,peer-reviewed journal publishing high quality research and review articles on all aspects of ornithology from all over the world.It aims to report the latest and most significant progress in ornithology and to encourage exchange of ideas among international ornithologists.As an Open Access journal,

  18. Images of photoreceptors in living primate eyes using adaptive optics two-photon ophthalmoscopy.

    Science.gov (United States)

    Hunter, Jennifer J; Masella, Benjamin; Dubra, Alfredo; Sharma, Robin; Yin, Lu; Merigan, William H; Palczewska, Grazyna; Palczewski, Krzysztof; Williams, David R

    2010-01-01

    In vivo two-photon imaging through the pupil of the primate eye has the potential to become a useful tool for functional imaging of the retina. Two-photon excited fluorescence images of the macaque cone mosaic were obtained using a fluorescence adaptive optics scanning laser ophthalmoscope, overcoming the challenges of a low numerical aperture, imperfect optics of the eye, high required light levels, and eye motion. Although the specific fluorophores are as yet unknown, strong in vivo intrinsic fluorescence allowed images of the cone mosaic. Imaging intact ex vivo retina revealed that the strongest two-photon excited fluorescence signal comes from the cone inner segments. The fluorescence response increased following light stimulation, which could provide a functional measure of the effects of light on photoreceptors. PMID:21326644

  19. Abnormal photoreceptor outer segment development and early retinal degeneration in kif3a mutant zebrafish.

    Science.gov (United States)

    Raghupathy, Rakesh K; Zhang, Xun; Alhasani, Reem H; Zhou, Xinzhi; Mullin, Margaret; Reilly, James; Li, Wenchang; Liu, Mugen; Shu, Xinhua

    2016-08-01

    Photoreceptors are highly specialized sensory neurons that possess a modified primary cilium called the outer segment. Photoreceptor outer segment formation and maintenance require highly active protein transport via a process known as intraflagellar transport. Anterograde transport in outer segments is powered by the heterotrimeric kinesin II and coordinated by intraflagellar transport proteins. Here, we describe a new zebrafish model carrying a nonsense mutation in the kinesin II family member 3A (kif3a) gene. Kif3a mutant zebrafish exhibited curved body axes and kidney cysts. Outer segments were not formed in most parts of the mutant retina, and rhodopsin was mislocalized, suggesting KIF3A has a role in rhodopsin trafficking. Both rod and cone photoreceptors degenerated rapidly between 4 and 9 days post fertilization, and electroretinography response was not detected in 7 days post fertilization mutant larvae. Loss of KIF3A in zebrafish also resulted in an intracellular transport defect affecting anterograde but not retrograde transport of organelles. Our results indicate KIF3A plays a conserved role in photoreceptor outer segment formation and intracellular transport. PMID:27470972

  20. Arf-like Protein 3 (ARL3) Regulates Protein Trafficking and Ciliogenesis in Mouse Photoreceptors.

    Science.gov (United States)

    Hanke-Gogokhia, Christin; Wu, Zhijian; Gerstner, Cecilia D; Frederick, Jeanne M; Zhang, Houbin; Baehr, Wolfgang

    2016-03-25

    Arf-like protein 3 (ARL3) is a ubiquitous small GTPase expressed in ciliated cells of plants and animals. Germline deletion ofArl3in mice causes multiorgan ciliopathy reminiscent of Bardet-Biedl or Joubert syndromes. As photoreceptors are elegantly compartmentalized and have cilia, we probed the function of ARL3 (ADP-ribosylation factor (Arf)-like 3 protein) by generating rod photoreceptor-specific (prefix(rod)) and retina-specific (prefix(ret))Arl3deletions. In predegenerate(rod)Arl3(-/-)mice, lipidated phototransduction proteins showed trafficking deficiencies, consistent with the role of ARL3 as a cargo displacement factor for lipid-binding proteins. By contrast,(ret)Arl3(-/-)rods and cones expressing Cre recombinase during embryonic development formed neither connecting cilia nor outer segments and degenerated rapidly. Absence of cilia infers participation of ARL3 in ciliogenesis and axoneme formation. Ciliogenesis was rescued, and degeneration was reversed in part by subretinal injection of adeno-associated virus particles expressing ARL3-EGFP. The conditional knock-out phenotypes permitted identification of two ARL3 functions, both in the GTP-bound form as follows: one as a regulator of intraflagellar transport participating in photoreceptor ciliogenesis and the other as a cargo displacement factor transporting lipidated protein to the outer segment. Surprisingly, a farnesylated inositol polyphosphate phosphatase only trafficked from the endoplasmic reticulum to the Golgi, thereby excluding it from a role in photoreceptor cilia physiology. PMID:26814127

  1. Environmental enrichment extends photoreceptor survival and visual function in a mouse model of retinitis pigmentosa.

    Directory of Open Access Journals (Sweden)

    Ilaria Barone

    Full Text Available Slow, progressive rod degeneration followed by cone death leading to blindness is the pathological signature of all forms of human retinitis pigmentosa (RP. Therapeutic schemes based on intraocular delivery of neuroprotective agents prolong the lifetime of photoreceptors and have reached the stage of clinical trial. The success of these approaches depends upon optimization of chronic supply and appropriate combination of factors. Environmental enrichment (EE, a novel neuroprotective strategy based on enhanced motor, sensory and social stimulation, has already been shown to exert beneficial effects in animal models of various disorders of the CNS, including Alzheimer and Huntington disease. Here we report the results of prolonged exposure of rd10 mice, a mutant strain undergoing progressive photoreceptor degeneration mimicking human RP, to such an enriched environment from birth. By means of microscopy of retinal tissue, electrophysiological recordings, visual behaviour assessment and molecular analysis, we show that EE considerably preserves retinal morphology and physiology as well as visual perception over time in rd10 mutant mice. We find that protective effects of EE are accompanied by increased expression of retinal mRNAs for CNTF and mTOR, both factors known as instrumental to photoreceptor survival. Compared to other rescue approaches used in similar animal models, EE is highly effective, minimally invasive and results into a long-lasting retinal protection. These results open novel perspectives of research pointing to environmental strategies as useful tools to extend photoreceptor survival.

  2. Alterations to retinal architecture prior to photoreceptor loss in a mouse model of retinitis pigmentosa.

    Science.gov (United States)

    Roche, Sarah L; Wyse-Jackson, Alice C; Byrne, Ashleigh M; Ruiz-Lopez, Ana M; Cotter, Thomas G

    2016-01-01

    Mouse models of retinitis pigmentosa (RP) are essential tools in the pursuit to understand fully what cell types and processes underlie the degeneration observed in RP. Knowledge of these processes is required if we are to develop successful therapies to treat this currently incurable disease. We have used the rd10 mouse model of RP to study retinal morphology prior to photoreceptor loss, using immunohistochemistry and confocal microscopy on cryosections, since little is known about how the mutation affects the retina during this period. We report novel findings that the mutation in the rd10 mouse results in retinal abnormalities earlier than was previously thought. Defects in rod and cone outer segments, bipolar cells, amacrine cells and photoreceptor synapses were apparent in the retina during early stages of postnatal retinal development and prior to the loss of photoreceptors. Additionally, we observed a dramatic response of glial cells during this period. Microglia responded as early as postnatal day (P) 5; ?13 days before any photoreceptor loss is detected with Müller glia and astrocytes exhibiting changes from P10 and P15 respectively. Overall, these findings present pathological aspects to the postnatal development of the rd10 retina, contributing significantly to our understanding of disease onset and progression in the rd10 mouse and provide a valuable resource for the study of retinal dystrophies. PMID:27160072

  3. Photoreceptor Sensory Cilium: Traversing the Ciliary Gate.

    Science.gov (United States)

    Khanna, Hemant

    2015-01-01

    Cilia are antenna-like extensions of the plasma membrane found in nearly all cell types. In the retina of the eye, photoreceptors develop unique sensory cilia. Not much was known about the mechanisms underlying the formation and function of photoreceptor cilia, largely because of technical limitations and the specific structural and functional modifications that cannot be modeled in vitro. With recent advances in microscopy techniques and molecular and biochemical approaches, we are now beginning to understand the molecular basis of photoreceptor ciliary architecture, ciliary function and its involvement in human diseases. Here, I will discuss the studies that have revealed new knowledge of how photoreceptor cilia regulate their identity and function while coping with high metabolic and trafficking demands associated with processing light signal. PMID:26501325

  4. Photoreceptor Sensory Cilium: Traversing the Ciliary Gate

    Directory of Open Access Journals (Sweden)

    Hemant Khanna

    2015-10-01

    Full Text Available Cilia are antenna-like extensions of the plasma membrane found in nearly all cell types. In the retina of the eye, photoreceptors develop unique sensory cilia. Not much was known about the mechanisms underlying the formation and function of photoreceptor cilia, largely because of technical limitations and the specific structural and functional modifications that cannot be modeled in vitro. With recent advances in microscopy techniques and molecular and biochemical approaches, we are now beginning to understand the molecular basis of photoreceptor ciliary architecture, ciliary function and its involvement in human diseases. Here, I will discuss the studies that have revealed new knowledge of how photoreceptor cilia regulate their identity and function while coping with high metabolic and trafficking demands associated with processing light signal.

  5. Phototransduction and the Evolution of Photoreceptors

    OpenAIRE

    Fain, Gordon L; Hardie, Roger; Laughlin, Simon B

    2010-01-01

    Photoreceptors in metazoans can be grouped into two classes, with their photoreceptive membrane derived either from cilia or microvilli. Both classes use some form of the visual pigment protein opsin, which together with 11-cis retinaldehyde absorbs light and activates a G-protein cascade, resulting in the opening or closing of ion channels. Considerable attention has recently been given to the molecular evolution of the opsins and other photoreceptor proteins; much is also known about transd...

  6. Photoreceptor Sensory Cilium: Traversing the Ciliary Gate

    OpenAIRE

    Hemant Khanna

    2015-01-01

    Cilia are antenna-like extensions of the plasma membrane found in nearly all cell types. In the retina of the eye, photoreceptors develop unique sensory cilia. Not much was known about the mechanisms underlying the formation and function of photoreceptor cilia, largely because of technical limitations and the specific structural and functional modifications that cannot be modeled in vitro. With recent advances in microscopy techniques and molecular and biochemical approaches, we are now begin...

  7. Retinal signal transmission in Duchenne muscular dystrophy: evidence for dysfunction in the photoreceptor/depolarizing bipolar cell pathway.

    OpenAIRE

    Fitzgerald, K M; Cibis, G W; Giambrone, S A; Harris, D J

    1994-01-01

    There have been reports of abnormal retinal neurotransmission determined by electroretinography in boys with Duchenne and Becker muscular dystrophy. Dystrophin may play a role in transmitting signals between photoreceptors and the excitatory synapse of the ON-bipolar cell. These electroretinographic changes appeared to be limited to the rod ON-pathway but we felt there was also similar abnormality in the cone ON-pathway. We used long-duration stimuli to separate ON-(depolarizing bipolar cell)...

  8. Avian influenza

    Directory of Open Access Journals (Sweden)

    Tjandra Y. Aditama

    2006-06-01

    Full Text Available Avian influenza, or “bird flu”, is a contagious disease of animals which crossed the species barrier to infect humans and gave a quite impact on public health in the world since 2004, especially due to the threat of pandemic situation. Until 1st March 2006, laboratory-confirmed human cases have been reported in seven countries: Cambodia, Indonesia, Thailand, Viet Nam, China, Iraq and Turkey with a total of 174 cases and 94 dead (54.02%. Indonesia has 27 cases, 20 were dead (74.07%. AI cases in Indonesia are more in male (62.5% and all have a symptom of fever. An influenza pandemic is a rare but recurrent event. An influenza pandemic happens when a new subtype emerges that has not previously circulated in humans. For this reason, avian H5N1 is a strain with pandemic potential, since it might ultimately adapt into a strain that is contagious among humans. Impact of the pandemic could include high rates of illness and worker absenteeism are expected, and these will contribute to social and economic disruption. Historically, the number of deaths during a pandemic has varied greatly. Death rates are largely determined by four factors: the number of people who become infected, the virulence of the virus, the underlying characteristics and vulnerability of affected populations, and the effectiveness of preventive measures. Accurate predictions of mortality cannot be made before the pandemic virus emerges and begins to spread. (Med J Indones 2006; 15:125-8Keywords: Avian Influenza, Pandemic

  9. Avian Influenza

    OpenAIRE

    Tjandra Y. Aditama

    2008-01-01

    Avian influenza, or “bird flu”, is a contagious disease of animals which crossed the species barrier to infect humans and gave a quite impact on public health in the world since 2004, especially due to the threat of pandemic situation. Until 1st March 2006, laboratory-confirmed human cases have been reported in seven countries: Cambodia, Indonesia, Thailand, Viet Nam, China, Iraq and Turkey with a total of 174 cases and 94 dead (54.02%). Indonesia has 27 cases, 20 were dead (74.07%). AI cases...

  10. Up-regulation of tumor necrosis factor superfamily genes in early phases of photoreceptor degeneration.

    Directory of Open Access Journals (Sweden)

    Sem Genini

    Full Text Available We used quantitative real-time PCR to examine the expression of 112 genes related to retinal function and/or belonging to known pro-apoptotic, cell survival, and autophagy pathways during photoreceptor degeneration in three early-onset canine models of human photoreceptor degeneration, rod cone dysplasia 1 (rcd1, X-linked progressive retinal atrophy 2 (xlpra2, and early retinal degeneration (erd, caused respectively, by mutations in PDE6B, RPGRORF15, and STK38L. Notably, we found that expression and timing of differentially expressed (DE genes correlated with the cell death kinetics. Gene expression profiles of rcd1 and xlpra2 were similar; however rcd1 was more severe as demonstrated by the results of the TUNEL and ONL thickness analyses, a greater number of genes that were DE, and the identification of altered expression that occurred at earlier time points. Both diseases differed from erd, where a smaller number of genes were DE. Our studies did not highlight the potential involvement of mitochondrial or autophagy pathways, but all three diseases were accompanied by the down-regulation of photoreceptor genes, and up-regulation of several genes that belong to the TNF superfamily, the extrinsic apoptotic pathway, and pro-survival pathways. These proteins were expressed by different retinal cells, including horizontal, amacrine, ON bipolar, and Müller cells, and suggest an interplay between the dying photoreceptors and inner retinal cells. Western blot and immunohistochemistry results supported the transcriptional regulation for selected proteins. This study highlights a potential role for signaling through the extrinsic apoptotic pathway in early cell death events and suggests that retinal cells other than photoreceptors might play a primary or bystander role in the degenerative process.

  11. Transcriptional regulation of rod photoreceptor homeostasis revealed by in vivo NRL targetome analysis.

    Directory of Open Access Journals (Sweden)

    Hong Hao

    Full Text Available A stringent control of homeostasis is critical for functional maintenance and survival of neurons. In the mammalian retina, the basic motif leucine zipper transcription factor NRL determines rod versus cone photoreceptor cell fate and activates the expression of many rod-specific genes. Here, we report an integrated analysis of NRL-centered gene regulatory network by coupling chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-Seq data from Illumina and ABI platforms with global expression profiling and in vivo knockdown studies. We identified approximately 300 direct NRL target genes. Of these, 22 NRL targets are associated with human retinal dystrophies, whereas 95 mapped to regions of as yet uncloned retinal disease loci. In silico analysis of NRL ChIP-Seq peak sequences revealed an enrichment of distinct sets of transcription factor binding sites. Specifically, we discovered that genes involved in photoreceptor function include binding sites for both NRL and homeodomain protein CRX. Evaluation of 26 ChIP-Seq regions validated their enhancer functions in reporter assays. In vivo knockdown of 16 NRL target genes resulted in death or abnormal morphology of rod photoreceptors, suggesting their importance in maintaining retinal function. We also identified histone demethylase Kdm5b as a novel secondary node in NRL transcriptional hierarchy. Exon array analysis of flow-sorted photoreceptors in which Kdm5b was knocked down by shRNA indicated its role in regulating rod-expressed genes. Our studies identify candidate genes for retinal dystrophies, define cis-regulatory module(s for photoreceptor-expressed genes and provide a framework for decoding transcriptional regulatory networks that dictate rod homeostasis.

  12. Iodoacetic acid, but not sodium iodate, creates an inducible swine model of photoreceptor damage.

    Science.gov (United States)

    Noel, Jennifer M; Fernandez de Castro, Juan P; Demarco, Paul J; Franco, Luisa M; Wang, Wei; Vukmanic, Eric V; Peng, Xiaoyan; Sandell, Julie H; Scott, Patrick A; Kaplan, Henry J; McCall, Maureen A

    2012-04-01

    Our purpose was to find a method to create a large animal model of inducible photoreceptor damage. To this end, we tested in domestic swine the efficacy of two chemical toxins, known to create photoreceptor damage in other species: Iodoacetic Acid (IAA) and Sodium Iodate (NaIO(3)). Intravenous (IV) administration of NaIO(3) up to 90 mg/kg had no effect on retinal function and 110 mg/kg was lethal. IV administration of IAA (5-20 mg/kg) produced concentration-dependent changes in visual function as measured by full-field and multi-focal electroretinograms (ffERG and mfERG), and 30 mg/kg IAA was lethal. The IAA-induced effects measured at two weeks were stable through eight weeks post-injection, the last time point investigated. IAA at 7.5, 10, and 12 mg/kg produce a concentration-dependent reduction in both ffERG b-wave and mfERG N1-P1 amplitudes compared to baseline at all post-injection times. Comparisons of dark- and light-adapted ffERG b-wave amplitudes show a more significant loss of rod relative to cone function. The fundus of swine treated with ≥10 mg/kg IAA was abnormal with thinner retinal vessels and pale optic discs, and we found no evidence of bone spicule formation. Histological evaluations show concentration-dependent outer retinal damage that correlates with functional changes. We conclude that NaIO(3,) is not an effective toxin in swine. In contrast, IAA can be used to create a rapidly inducible, selective, stable and concentration-dependent model of photoreceptor damage in swine retina. Because of these attributes this large animal model of controlled photoreceptor damage should be useful in the investigation of treatments to replace damaged photoreceptors. PMID:22251455

  13. Meckelin 3 is necessary for photoreceptor outer segment development in rat Meckel syndrome.

    Directory of Open Access Journals (Sweden)

    Sarika Tiwari

    Full Text Available Ciliopathies lead to multiorgan pathologies that include renal cysts, deafness, obesity and retinal degeneration. Retinal photoreceptors have connecting cilia joining the inner and outer segment that are responsible for transport of molecules to develop and maintain the outer segment process. The present study evaluated meckelin (MKS3 expression during outer segment genesis and determined the consequences of mutant meckelin on photoreceptor development and survival in Wistar polycystic kidney disease Wpk/Wpk rat using immunohistochemistry, analysis of cell death and electron microscopy. MKS3 was ubiquitously expressed throughout the retina at postnatal day 10 (P10 and P21. However, in the mature retina, MKS3 expression was restricted to photoreceptors and the retinal ganglion cell layer. At P10, both the wild type and homozygous Wpk mutant retina had all retinal cell types. In contrast, by P21, cells expressing rod- and cone-specific markers were fewer in number and expression of opsins appeared to be abnormally localized to the cell body. Cell death analyses were consistent with the disappearance of photoreceptor-specific markers and showed that the cells were undergoing caspase-dependent cell death. By electron microscopy, P10 photoreceptors showed rudimentary outer segments with an axoneme, but did not develop outer segment discs that were clearly present in the wild type counterpart. At p21 the mutant outer segments appeared much the same as the P10 mutant outer segments with only a short axoneme, while the wild-type controls had developed outer segments with many well-organized discs. We conclude that MKS3 is not important for formation of connecting cilium and rudimentary outer segments, but is critical for the maturation of outer segment processes.

  14. Meckelin 3 is necessary for photoreceptor outer segment development in rat Meckel syndrome.

    Science.gov (United States)

    Tiwari, Sarika; Hudson, Scott; Gattone, Vincent H; Miller, Caroline; Chernoff, Ellen A G; Belecky-Adams, Teri L

    2013-01-01

    Ciliopathies lead to multiorgan pathologies that include renal cysts, deafness, obesity and retinal degeneration. Retinal photoreceptors have connecting cilia joining the inner and outer segment that are responsible for transport of molecules to develop and maintain the outer segment process. The present study evaluated meckelin (MKS3) expression during outer segment genesis and determined the consequences of mutant meckelin on photoreceptor development and survival in Wistar polycystic kidney disease Wpk/Wpk rat using immunohistochemistry, analysis of cell death and electron microscopy. MKS3 was ubiquitously expressed throughout the retina at postnatal day 10 (P10) and P21. However, in the mature retina, MKS3 expression was restricted to photoreceptors and the retinal ganglion cell layer. At P10, both the wild type and homozygous Wpk mutant retina had all retinal cell types. In contrast, by P21, cells expressing rod- and cone-specific markers were fewer in number and expression of opsins appeared to be abnormally localized to the cell body. Cell death analyses were consistent with the disappearance of photoreceptor-specific markers and showed that the cells were undergoing caspase-dependent cell death. By electron microscopy, P10 photoreceptors showed rudimentary outer segments with an axoneme, but did not develop outer segment discs that were clearly present in the wild type counterpart. At p21 the mutant outer segments appeared much the same as the P10 mutant outer segments with only a short axoneme, while the wild-type controls had developed outer segments with many well-organized discs. We conclude that MKS3 is not important for formation of connecting cilium and rudimentary outer segments, but is critical for the maturation of outer segment processes. PMID:23516626

  15. Chloride equilibrium potential in salamander cones

    Directory of Open Access Journals (Sweden)

    Bryson Eric J

    2004-12-01

    Full Text Available Abstract Background GABAergic inhibition and effects of intracellular chloride ions on calcium channel activity have been proposed to regulate neurotransmission from photoreceptors. To assess the impact of these and other chloride-dependent mechanisms on release from cones, the chloride equilibrium potential (ECl was determined in red-sensitive, large single cones from the tiger salamander retinal slice. Results Whole cell recordings were done using gramicidin perforated patch techniques to maintain endogenous Cl- levels. Membrane potentials were corrected for liquid junction potentials. Cone resting potentials were found to average -46 mV. To measure ECl, we applied long depolarizing steps to activate the calcium-activated chloride current (ICl(Ca and then determined the reversal potential for the current component that was inhibited by the Cl- channel blocker, niflumic acid. With this method, ECl was found to average -46 mV. In a complementary approach, we used a Cl-sensitive dye, MEQ, to measure the Cl- flux produced by depolarization with elevated concentrations of K+. The membrane potentials produced by the various high K+ solutions were measured in separate current clamp experiments. Consistent with electrophysiological experiments, MEQ fluorescence measurements indicated that ECl was below -36 mV. Conclusions The results of this study indicate that ECl is close to the dark resting potential. This will minimize the impact of chloride-dependent presynaptic mechanisms in cone terminals involving GABAa receptors, glutamate transporters and ICl(Ca.

  16. Genetic deletion of S-opsin prevents rapid cone degeneration in a mouse model of Leber congenital amaurosis.

    Science.gov (United States)

    Zhang, Tao; Enemchukwu, Nduka O; Jones, Alex; Wang, Shixian; Dennis, Emily; Watt, Carl B; Pugh, Edward N; Fu, Yingbin

    2015-03-15

    Mutations in RPE65 or lecithin-retinol acyltransferase (LRAT) disrupt 11-cis-retinal synthesis and cause Leber congenital amaurosis (LCA), a severe hereditary blindness occurring in early childhood. The pathology is attributed to a combination of 11-cis-retinal deficiency and photoreceptor degeneration. The mistrafficking of cone membrane-associated proteins including cone opsins (M- and S-opsins), cone transducin (Gαt2), G-protein-coupled receptor kinase 1 (GRK1) and guanylate cyclase 1 (GC1) has been suggested to play a role in cone degeneration. However, their precise role in cone degeneration is unclear. Here we investigated the role of S-opsin (Opn1sw) in cone degeneration in Lrat(-) (/-), a murine model for LCA, by genetic ablation of S-opsin. We show that deletion of just one allele of S-opsin from Lrat(-) (/-) mice is sufficient to prevent the rapid cone degeneration for at least 1 month. Deletion of both alleles of S-opsin prevents cone degeneration for an extended period (at least 12 months). This genetic prevention is accompanied by a reduction of endoplasmic reticulum (ER) stress in Lrat(-) (/-) photoreceptors. Despite cone survival in Opn1sw(-/-)Lrat(-) (/-) mice, cone membrane-associated proteins (e.g. Gαt2, GRK1 and GC1) continue to have trafficking problems. Our results suggest that cone opsins are the 'culprit' linking 11-cis-retinal deficiency to cone degeneration in LCA. This result has important implications for the current gene therapy strategy that emphasizes the need for a combinatorial therapy to both improve vision and slow photoreceptor degeneration. PMID:25416279

  17. Monte Carlo methods for localization of cones given multielectrode retinal ganglion cell recordings.

    Science.gov (United States)

    Sadeghi, K; Gauthier, J L; Field, G D; Greschner, M; Agne, M; Chichilnisky, E J; Paninski, L

    2013-01-01

    It has recently become possible to identify cone photoreceptors in primate retina from multi-electrode recordings of ganglion cell spiking driven by visual stimuli of sufficiently high spatial resolution. In this paper we present a statistical approach to the problem of identifying the number, locations, and color types of the cones observed in this type of experiment. We develop an adaptive Markov Chain Monte Carlo (MCMC) method that explores the space of cone configurations, using a Linear-Nonlinear-Poisson (LNP) encoding model of ganglion cell spiking output, while analytically integrating out the functional weights between cones and ganglion cells. This method provides information about our posterior certainty about the inferred cone properties, and additionally leads to improvements in both the speed and quality of the inferred cone maps, compared to earlier "greedy" computational approaches. PMID:23194406

  18. Neuronatin is a stress-responsive protein of rod photoreceptors.

    Science.gov (United States)

    Shinde, Vishal; Pitale, Priyamvada M; Howse, Wayne; Gorbatyuk, Oleg; Gorbatyuk, Marina

    2016-07-22

    Neuronatin (NNAT) is a small transmembrane proteolipid that is highly expressed in the embryonic developing brain and several other peripheral tissues. This study is the first to provide evidence that NNAT is detected in the adult retina of various adult rod-dominant mammals, including wild-type (WT) rodents, transgenic rodents expressing mutant S334ter, P23H, or T17M rhodopsin, non-human primates, humans, and cone-dominant tree shrews. Immunohistochemical and quantitative real time polymerase chain reaction (qRT-PCR) analyses were applied to detect NNAT. Confocal microscopy analysis revealed that NNAT immunofluorescence is restricted to the outer segments (OSs) of photoreceptors without evidence of staining in other retinal cell types across all mammalian species. Moreover, in tree shrew retinas, we found NNAT to be co-localized with rhodopsin, indicating its predominant expression in rods. The rod-derived expression of NNAT was further confirmed by qRT-PCR in isolated rod photoreceptor cells. We also used these cells to mimic cellular stress in transgenic retinas by treating them with the endoplasmic reticulum stress inducer, tunicamycin. Thus, our data revealed accumulation of NNAT around the nucleus as compared to dispersed localization of NNAT within control cells. This distribution coincided with the partial intracellular mislocalization of NNAT to the outer nuclear layer observed in transgenic retinas. In addition, stressed retinas demonstrated an increase of NNAT mRNA and protein levels. Therefore, our study demonstrated that NNAT is a novel stress-responsive protein with a potential structural and/or functional role in adult mammalian retinas. PMID:27109921

  19. Comparative study of photoreceptor and retinal ganglion cell topography and spatial resolving power in Dipsadidae snakes.

    Science.gov (United States)

    Hauzman, Einat; Bonci, Daniela M O; Grotzner, Sonia R; Mela, Maritana; Liber, André M P; Martins, Sonia L; Ventura, Dora F

    2014-01-01

    The diurnal Dipsadidae snakes Philodryas olfersii and P. patagoniensis are closely related in their phylogeny but inhabit different ecological niches. P. olfersii is arboreal, whereas P. patagoniensis is preferentially terrestrial. The goal of the present study was to compare the density and topography of neurons, photoreceptors, and cells in the ganglion cell layer in the retinas of these two species using immunohistochemistry and Nissl staining procedures and estimate the spatial resolving power of their eyes based on the ganglion cell peak density. Four morphologically distinct types of cones were observed by scanning electron microscopy, 3 of which were labeled with anti-opsin antibodies: large single cones and double cones labeled by the antibody JH492 and small single cones labeled by the antibody JH455. The average densities of photoreceptors and neurons in the ganglion cell layer were similar in both species (∼10,000 and 7,000 cells·mm(-2), respectively). The estimated spatial resolving power was also similar, ranging from 2.4 to 2.7 cycles·degree(-1). However, the distribution of neurons had different specializations. In the arboreal P. olfersii, the isodensity maps had a horizontal visual streak, with a peak density in the central region and a lower density in the dorsal retina. This organization might be relevant for locomotion and hunting behavior in the arboreal layer. In the terrestrial P. patagoniensis, a concentric pattern of decreasing cell density emanated from an area centralis located in the naso-ventral retina. Lower densities were observed in the dorsal region. The ventrally high density improves the resolution in the superior visual field and may be an important adaptation for terrestrial snakes to perceive the approach of predators from above. PMID:25342570

  20. Avian respiratory system disorders

    Science.gov (United States)

    Olsen, G.H.

    1989-01-01

    Diagnosing and treating respiratory diseases in avian species requires a basic knowledge about the anatomy and physiology of this system in birds. Differences between mammalian and avian respiratory system function, diagnosis, and treatment are highlighted.

  1. Avian Influenza in Birds

    Science.gov (United States)

    ... Research Making a Candidate Vaccine Virus Related Links Influenza Types Seasonal Avian Swine Variant Pandemic Other Get ... Submit What's this? Submit Button Past Newsletters Avian Influenza in Birds Language: English Español Recommend on ...

  2. Avian Influenza (Bird Flu)

    Science.gov (United States)

    ... Research Making a Candidate Vaccine Virus Related Links Influenza Types Seasonal Avian Swine Variant Pandemic Other Get ... this? Submit Button Past Newsletters Information on Avian Influenza Language: English Español Recommend on Facebook Tweet ...

  3. Evolutionary loss of cone photoreception in balaenid whales reveals circuit stability in the mammalian retina.

    Science.gov (United States)

    Schweikert, Lorian E; Fasick, Jeffry I; Grace, Michael S

    2016-10-01

    The classical understanding of mammalian vision is that it occurs through "duplex" retinae containing both rod and cone photoreceptors, the signals from which are processed through rod- and/or cone-specific signaling pathways. The recent discovery of rod monochromacy in some cetacean lineages provides a novel opportunity to investigate the effects of an evolutionary loss of cone photoreception on retinal organization. Sequence analysis of right whale (Eubalaena glacialis; family Balaenidae) cDNA derived from long-wavelength sensitive (LWS) cone opsin mRNA identified several mutations in the opsin coding sequence, suggesting the loss of cone cell function, but maintenance of non-photosensitive, cone opsin mRNA-expressing cells in the retina. Subsequently, we investigated the retina of the closely related bowhead whale (Balaena mysticetus; family Balaenidae) to determine how the loss of cone-mediated photoreception affects light signaling pathways in the retina. Anti-opsin immunofluorescence demonstrated the total loss of cone opsin expression in B. mysticetus, whereas light microscopy, transmission electron microscopy, and bipolar cell (protein kinase C-α [PKC-α] and recoverin) immunofluorescence revealed the maintenance of cone soma, putative cone pedicles, and both rod and cone bipolar cell types. These findings represent the first immunological and anatomical evidence of a naturally occurring rod-monochromatic mammalian retina, and suggest that despite the loss of cone-mediated photoreception, the associated cone signaling structures (i.e., cone synapses and cone bipolar cells) may be maintained for multichannel rod-based signaling in balaenid whales. J. Comp. Neurol. 524:2873-2885, 2016. © 2016 Wiley Periodicals, Inc. PMID:26972896

  4. Photoreceptors mapping from past history till date.

    Science.gov (United States)

    Parihar, Parul; Singh, Rachana; Singh, Samiksha; Tripathi, Durgesh Kumar; Chauhan, Devendra Kumar; Singh, Vijay Pratap; Prasad, Sheo Mohan

    2016-09-01

    The critical source of information in plants is light, which is perceived by receptors present in plants and animals. Receptors present in plant and animal system regulate important processes, and knowing the chromophores and signalling domains for each receptor could pave a way to trace out links between these receptors. The signalling mechanism for each receptor will give insight knowledge. This review has focussed on the photoreceptors from past history till date, that have evolved in the plant as well as in the animal system (to lesser extent). We have also focussed our attention on finding the links between the receptors by showing the commonalities as well as the differences between them, and also tried to trace out the links with the help of chromophores and signalling domain. Several photoreceptors have been traced out, which share similarity in the chromophore as well as in the signalling domain, which indicate towards the evolution of photoreceptors from one another. For instance, cryptochrome has been found to evolve three times from CPD photolyase as well as evolution of different types of phytochrome is a result of duplication and divergence. In addition, similarity between the photoreceptors suggested towards evolution from one another. This review has also discussed possible mechanism for each receptor i.e. how they regulate developmental processes and involve what kinds of regulators and also gives an insight on signalling mechanisms by these receptors. This review could also be a new initiative in the study of UVR8 associated studies. PMID:27387671

  5. Cold knife cone biopsy

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003910.htm Cold knife cone biopsy To use the sharing features on this page, please enable JavaScript. A cold knife cone biopsy (conization) is surgery to remove ...

  6. The giant mottled eel, Anguilla marmorata, uses blue-shifted rod photoreceptors during upstream migration.

    Directory of Open Access Journals (Sweden)

    Feng-Yu Wang

    Full Text Available Catadromous fishes migrate between ocean and freshwater during particular phases of their life cycle. The dramatic environmental changes shape their physiological features, e.g. visual sensitivity, olfactory ability, and salinity tolerance. Anguilla marmorata, a catadromous eel, migrates upstream on dark nights, following the lunar cycle. Such behavior may be correlated with ontogenetic changes in sensory systems. Therefore, this study was designed to identify changes in spectral sensitivity and opsin gene expression of A. marmorata during upstream migration. Microspectrophotometry analysis revealed that the tropical eel possesses a duplex retina with rod and cone photoreceptors. The λmax of rod cells are 493, 489, and 489 nm in glass, yellow, and wild eels, while those of cone cells are 508, and 517 nm in yellow, and wild eels, respectively. Unlike European and American eels, Asian eels exhibited a blue-shifted pattern of rod photoreceptors during upstream migration. Quantitative gene expression analyses of four cloned opsin genes (Rh1f, Rh1d, Rh2, and SWS2 revealed that Rh1f expression is dominant at all three stages, while Rh1d is expressed only in older yellow eel. Furthermore, sequence comparison and protein modeling studies implied that a blue shift in Rh1d opsin may be induced by two known (N83, S292 and four putative (S124, V189, V286, I290 tuning sites adjacent to the retinal binding sites. Finally, expression of blue-shifted Rh1d opsin resulted in a spectral shift in rod photoreceptors. Our observations indicate that the giant mottled eel is color-blind, and its blue-shifted scotopic vision may influence its upstream migration behavior and habitat choice.

  7. Morphological characterization and topographic analysis of multiple photoreceptor types in the retinae of mesopelagic hatchetfishes with tubular eyes

    Directory of Open Access Journals (Sweden)

    Lauren Michelle Biagioni

    2016-03-01

    Full Text Available Marine hatchetfishes, Argyropelecus spp., are one of the 14 genera of mesopelagic teleosts, which possess tubular eyes. The tubular eyes are positioned dorsally on the head and consist of a main retina, which subtends a large dorsal binocular field, and an accessory retina, which subtends the lateral monocular visual field. The topographic distribution of photoreceptors in the retina of Argyropelecus sladeni, A. affinis and A. aculeatus was determined using a random, unbiased and systematic stereological approach, which consistently revealed a region of high density (area centralis in the central region of the main retina (up to a peak of 96,000 receptors per mm2 and a relatively homogeneous density of photoreceptors in the accessory retina (of approximately 20,000 receptors per mm2. The position of the area centralis in the main retina indicates this retinal region subserves greater spatial resolution in the centre of the dorsal binocular visual field. Light microscopy and transmission electron microscopy also revealed the presence of multiple photoreceptor types (two rod-like and one cone-like based on the size and shape of the inner and outer segments and ultrastructural differences in the ellipsoidal region. The presence of multiple photoreceptor types in these tubular-eyed, mesopelagic hatchetfishes may reflect the need for the visual system to function under different lighting conditions during vertical migratory behavior, especially given their unique dorsally-facing eyes.

  8. cGMP production of patient-specific iPSCs and photoreceptor precursor cells to treat retinal degenerative blindness.

    Science.gov (United States)

    Wiley, Luke A; Burnight, Erin R; DeLuca, Adam P; Anfinson, Kristin R; Cranston, Cathryn M; Kaalberg, Emily E; Penticoff, Jessica A; Affatigato, Louisa M; Mullins, Robert F; Stone, Edwin M; Tucker, Budd A

    2016-01-01

    Immunologically-matched, induced pluripotent stem cell (iPSC)-derived photoreceptor precursor cells have the potential to restore vision to patients with retinal degenerative diseases like retinitis pigmentosa. The purpose of this study was to develop clinically-compatible methods for manufacturing photoreceptor precursor cells from adult skin in a non-profit cGMP environment. Biopsies were obtained from 35 adult patients with inherited retinal degeneration and fibroblast lines were established under ISO class 5 cGMP conditions. Patient-specific iPSCs were then generated, clonally expanded and validated. Post-mitotic photoreceptor precursor cells were generated using a stepwise cGMP-compliant 3D differentiation protocol. The recapitulation of the enhanced S-cone phenotype in retinal organoids generated from a patient with NR2E3 mutations demonstrated the fidelity of these protocols. Transplantation into immune compromised animals revealed no evidence of abnormal proliferation or tumor formation. These studies will enable clinical trials to test the safety and efficiency of patient-specific photoreceptor cell replacement in humans. PMID:27471043

  9. CNGB3-Achromatopsia Clinical Trial With CNTF: Diminished Rod Pathway Responses With No Evidence of Improvement in Cone Function

    OpenAIRE

    ZEIN, WADIH M.; Jeffrey, Brett G.; Wiley, Henry E.; Turriff, Amy E.; Tumminia, Santa J.; Tao, Weng; Bush, Ronald A.; Marangoni, Dario; Wen, Rong; Wei, Lisa L.; Sieving, Paul A.

    2014-01-01

    CNTF protects rod photoreceptors in animal retinal degeneration models. A recent study showed CNTF partially restores cone function in dogs with CNGB3 mutations. Since CNGB3 mutations account for 50% of human achromatopsia, we explored potential benefits of CNTF for CNGB3-achromats.

  10. Differential contribution of rod and cone circadian clocks in driving retinal melatonin rhythms in Xenopus.

    Directory of Open Access Journals (Sweden)

    Naoto Hayasaka

    Full Text Available BACKGROUND: Although an endogenous circadian clock located in the retinal photoreceptor layer governs various physiological events including melatonin rhythms in Xenopus laevis, it remains unknown which of the photoreceptors, rod and/or cone, is responsible for the circadian regulation of melatonin release. METHODOLOGY/PRINCIPAL FINDINGS: We selectively disrupted circadian clock function in either the rod or cone photoreceptor cells by generating transgenic Xenopus tadpoles expressing a dominant-negative CLOCK (XCLΔQ under the control of a rod or cone-specific promoter. Eyecup culture and continuous melatonin measurement revealed that circadian rhythms of melatonin release were abolished in a majority of the rod-specific XCLΔQ transgenic tadpoles, although the percentage of arrhythmia was lower than that of transgenic tadpole eyes expressing XCLΔQ in both rods and cones. In contrast, whereas a higher percentage of arrhythmia was observed in the eyes of the cone-specific XCLΔQ transgenic tadpoles compare to wild-type counterparts, the rate was significantly lower than in rod-specific transgenics. The levels of the transgene expression were comparable between these two different types of transgenics. In addition, the average overall melatonin levels were not changed in the arrhythmic eyes, suggesting that CLOCK does not affect absolute levels of melatonin, only its temporal expression pattern. CONCLUSIONS/SIGNIFICANCE: These results suggest that although the Xenopus retina is made up of approximately equal numbers of rods and cones, the circadian clocks in the rod cells play a dominant role in driving circadian melatonin rhythmicity in the Xenopus retina, although some contribution of the clock in cone cells cannot be excluded.

  11. Human neural progenitor cells decrease photoreceptor degeneration, normalize opsin distribution and support synapse structure in cultured porcine retina.

    Science.gov (United States)

    Mollick, Tanzina; Mohlin, Camilla; Johansson, Kjell

    2016-09-01

    Retinal neurodegenerative disorders like retinitis pigmentosa, age-related macular degeneration, diabetic retinopathy and retinal detachment decrease retinal functionality leading to visual impairment. The pathological events are characterized by photoreceptor degeneration, synaptic disassembly, remodeling of postsynaptic neurons and activation of glial cells. Despite intense research, no effective treatment has been found for these disorders. The current study explores the potential of human neural progenitor cell (hNPC) derived factors to slow the degenerative processes in adult porcine retinal explants. Retinas were cultured for 3 days with or without hNPCs as a feeder layer and investigated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), immunohistochemical, western blot and quantitative real time-polymerase chain reaction (qRT-PCR) techniques. TUNEL showed that hNPCs had the capacity to limit photoreceptor cell death. Among cone photoreceptors, hNPC coculture resulted in better maintenance of cone outer segments and reduced opsin mislocalization. Additionally, maintained synaptic structural integrity and preservation of second order calbindin positive horizontal cells was also observed. However, Müller cell gliosis only seemed to be alleviated in terms of reduced Müller cell density. Our observations indicate that at 3 days of coculture, hNPC derived factors had the capacity to protect photoreceptors, maintain synaptic integrity and support horizontal cell survival. Human neural progenitor cell applied treatment modalities may be an effective strategy to help maintain retinal functionality in neurodegenerative pathologies. Whether hNPCs can independently hinder Müller cell gliosis by utilizing higher concentrations or by combination with other pharmacological agents still needs to be determined. PMID:27369448

  12. Isolation of chick retina cones and study of their diversity based on oil droplet colour and nucleus position

    OpenAIRE

    López-López, R.; LÓPEZ-GALLARDO, M.; Pérez-Álvarez, M. J.; Prada, C.

    2008-01-01

    The chick retina has four morphological cone types that differ not only in shape, but also in the visual pigment in the outer segment, in the colour of the oil droplet in the inner segment and in synaptic connectivity. Neither the type of droplet nor the visual pigment has been definitively established for the four cone types. The main aim of the present work has been the isolation of entire live photoreceptors in order to study the oil droplet colour in each cone type and to quantify each ty...

  13. Quotient Normed Cones

    Indian Academy of Sciences (India)

    Oscar Valero

    2006-05-01

    Given a normed cone (, ) and a subcone , we construct and study the quotient normed cone $(X/Y,\\tilde{p})$ generated by . In particular we characterize the bicompleteness of $(X/Y,\\tilde{p})$ in terms of the bicompleteness of (, ), and prove that the dual quotient cone $((X/Y)^∗,\\|\\cdot\\|_{\\tilde{p},u})$ can be identified as a distinguished subcone of the dual cone $(X^∗,\\|\\cdot\\|_{\\tilde{p},u})$. Furthermore, some parts of the theory are presented in the general setting of the space $CL(X,Y)$ of all continuous linear mappings from a normed cone (, ) to a normed cone (, ), extending several well-known results related to open continuous linear mappings between normed linear spaces.

  14. Brain photoreceptor pathways contributing to circadian rhythmicity in crayfish.

    Science.gov (United States)

    Sullivan, Jeremy M; Genco, Maria C; Marlow, Elizabeth D; Benton, Jeanne L; Beltz, Barbara S; Sandeman, David C

    2009-08-01

    Freshwater crayfish have three known photoreceptive systems: the compound eyes, extraretinal brain photoreceptors, and caudal photoreceptors. The primary goal of the work described here was to explore the contribution of the brain photoreceptors to circadian locomotory activity and define some of the underlying neural pathways. Immunocytochemical studies of the brain photoreceptors in the parastacid (southern hemisphere) crayfish Cherax destructor reveal their expression of the blue light-sensitive photopigment cryptochrome and the neurotransmitter histamine. The brain photoreceptors project to two small protocerebral neuropils, the brain photoreceptor neuropils (BPNs), where they terminate among fibers expressing the neuropeptide pigment-dispersing hormone (PDH), a signaling molecule in arthropod circadian systems. Comparable pathways are also described in the astacid (northern hemisphere) crayfish Procambarus clarkii. Despite exhibiting markedly different diurnal locomotor activity rhythms, removal of the compound eyes and caudal photoreceptors in both C. destructor and P. clarkii (leaving the brain photoreceptors intact) does not abolish the normal light/dark activity cycle in either species, nor prevent the entrainment of their activity cycles to phase shifts of the light/dark period. These results suggest, therefore, that crayfish brain photoreceptors are sufficient for the entrainment of locomotor activity rhythms to photic stimuli, and that they can act in the absence of the compound eyes and caudal photoreceptors. We also demonstrate that the intensity of PDH expression in the BPNs varies in phase with the locomotor activity rhythm of both crayfish species. Together, these findings suggest that the brain photoreceptor cells can function as extraretinal circadian photoreceptors and that the BPN represents part of an entrainment pathway synchronizing locomotor activity to environmental light/dark cycles, and implicating the neuropeptide PDH in these functions

  15. Cloning and characterization of mr-s, a novel SAM domain protein, predominantly expressed in retinal photoreceptor cells

    Directory of Open Access Journals (Sweden)

    Koike Chieko

    2006-03-01

    Full Text Available Abstract Background Sterile alpha motif (SAM domains are ~70 residues long and have been reported as common protein-protein interaction modules. This domain is found in a large number of proteins, including Polycomb group (PcG proteins and ETS family transcription factors. In this work, we report the cloning and functional characterization of a novel SAM domain-containing protein, which is predominantly expressed in retinal photoreceptors and the pineal gland and is designated mouse mr-s (major retinal SAM domain protein. Results mr-s is evolutionarily conserved from zebrafish through human, organisms through which the mechanism of photoreceptor development is also highly conserved. Phylogenetic analysis suggests that the SAM domain of mr-s is most closely related to a mouse polyhomeotic (ph ortholog, Mph1/Rae28, which is known as an epigenetic molecule involved in chromatin modifications. These findings provide the possibility that mr-s may play a critical role by regulating gene expression in photoreceptor development. mr-s is preferentially expressed in the photoreceptors at postnatal day 3–6 (P3-6, when photoreceptors undergo terminal differentiation, and in the adult pineal gland. Transcription of mr-s is directly regulated by the cone-rod homeodomain protein Crx. Immunoprecipitation assay showed that the mr-s protein self-associates mainly through the SAM domain-containing region as well as ph. The mr-s protein localizes mainly in the nucleus, when mr-s is overexpressed in HEK293T cells. Moreover, in the luciferase assays, we found that mr-s protein fused to GAL4 DNA-binding domain functions as a transcriptional repressor. We revealed that the repression activity of mr-s is not due to a homophilic interaction through its SAM domain but to the C-terminal region. Conclusion We identified a novel gene, mr-s, which is predominantly expressed in retinal photoreceptors and pineal gland. Based on its expression pattern and biochemical analysis

  16. CNTF induces regeneration of cone outer segments in a rat model of retinal degeneration.

    Directory of Open Access Journals (Sweden)

    Yiwen Li

    Full Text Available BACKGROUND: Cone photoreceptors are responsible for color and central vision. In the late stage of retinitis pigmentosa and in geographic atrophy associated with age-related macular degeneration, cone degeneration eventually causes loss of central vision. In the present work, we investigated cone degeneration secondary to rod loss in the S334ter-3 transgenic rats carrying the rhodopsin mutation S334ter. METHODOLOGY/PRINCIPAL FINDINGS: Recombinant human ciliary neurotrophic factor (CNTF was delivered by intravitreal injection to the left eye of an animal, and vehicle to the right eye. Eyes were harvested 10 days after injection. Cone outer segments (COS, and cell bodies were identified by staining with peanut agglutinin and cone arrestin antibodies in whole-mount retinas. For long-term treatment with CNTF, CNTF secreting microdevices were implanted into the left eyes at postnatal day (PD 20 and control devices into the right eyes. Cone ERG was recorded at PD 160 from implanted animals. Our results demonstrate that an early sign of cone degeneration is the loss of COS, which concentrated in many small areas throughout the retina and is progressive with age. Treatment with CNTF induces regeneration of COS and thus reverses the degeneration process in early stages of cone degeneration. Sustained delivery of CNTF prevents cones from degeneration and helps them to maintain COS and light-sensing function. CONCLUSIONS/SIGNIFICANCE: Loss of COS is an early sign of secondary cone degeneration whereas cell death occurs much later. At early stages, degenerating cones are capable of regenerating outer segments, indicating the reversal of the degenerative process. Sustained delivery of CNTF preserves cone cells and their function. Long-term treatment with CNTF starting at early stages of degeneration could be a viable strategy for preservation of central vision for patients with retinal degenerations.

  17. Pathogenesis of progressive rod-cone degeneration in miniature poodles

    International Nuclear Information System (INIS)

    Visual cell pathologic changes and outer segment renewal were investigated in miniature poodles with progressive rod-cone degeneration. Early in this disease, visual cells in the posterior pole and equatorial regions show outer segment lamellar disorientation and vesicular profiles. Visual cells are normal in the periphery. Outer segment renewal determined after intravitreal injection of 3H-leucine was abnormally slower in affected animals than in controls. This renewal abnormality was similar in structurally normal and diseased photoreceptors, suggesting that the renewal defect is the earliest recognizable abnormality in the disease. The pigment epithelium was normal; the presence and density of pigment did not appear to affect the extent and severity of the disease or modify the abnormal renewal rate. As the disease progressed, photoreceptor outer segments were lost, and the remaining diminutive photoreceptors accumulated label in the inner segment and perinuclear zones. Sodium dodecyl sulfate gel electrophoresis of crude rod outer segment preparations showed no differences in opsin synthesis between normal and affected retinas early in the disease, but opsin synthesis decreased in the late stage of the disease

  18. Cone outer segment shedding in the goldfish retina characterized with the 3H-fucose technique

    International Nuclear Information System (INIS)

    After an intravitreal injection of 3H-fucose, red- and blue-sensitive cone outer segments (OSs) in the goldfish retina became heavily labeled, green-sensitive cone OSs showed light labeling, and rod OSs showed virtually no labeling. Fish were maintained in white light (light/dark: 12 hr/12 hr; 6 to 10 weeks) and were injected with 3H-fucose 24 hr before sacrifice. After light onset, only phagosomes with no label were found in the retinal pigment epithelium (RPE); after light offset, phagosomes with heavy, light, or no label were found in the RPE. A broad peak of cone OS shedding derived from all cone types was found beginning 2 hr after light offset and returning to baseline levels after 12 hr, with a maximum at 4 to 6 hr. When the white light was replaced with red light during the final 24 hr (irradiance matched to the white light at 625 nm), the green cones showed a reduction in shedding by 62%, the rods showed a 48% reduction in shedding, and the number of heavily labeled phagosomes was reduced by 24% (a value that may reflect normal and red cone shedding and a reduction in blue cone shedding). The results suggest that chromatic stimulation during the light period may influence the shedding response of a given class of cone OS. Finally, the 3H-fucose technique is useful for determination of the photoreceptor OS from which a given phagosome in the RPE originates in this species

  19. Time-derivative adaptive silicon photoreceptor array

    OpenAIRE

    Delbrück, Tobi; Mead, Carver A.

    1991-01-01

    We designed and tested a two-dimensional silicon receptor array constructed from pixels that temporally high-pass filter the incident image. There are no surround interactions in the array; all pixels operate independently except for their correlation due to the input image. The high- pass output signal is computed by sampling the output of an adaptive, high-gain, logarithmic photoreceptor during the scanout of the array. After a pixel is sampled, the output of the pixel is reset to a fixed v...

  20. Hydroxyl radicals cause fluctuation in intracellular ferrous ion levels upon light exposure during photoreceptor cell death.

    Science.gov (United States)

    Imamura, Tomoyo; Hirayama, Tasuku; Tsuruma, Kazuhiro; Shimazawa, Masamitsu; Nagasawa, Hideko; Hara, Hideaki

    2014-12-01

    Iron accumulation is a potential pathogenic event often seen in age-related macular degeneration (AMD) patients. In this study, we focused on the relationship between AMD pathology and concentrations of ferrous ion, which is a highly reactive oxygen generator in biological systems. Murine cone-cells-derived 661 W cells were exposed to white fluorescence light at 2500 lx for 1, 3, 6, or 12 h. Levels of ferrous ions, reactive oxygen species (ROS), and hydroxyl radicals were detected by RhoNox-1, a novel fluorescent probe for the selective detection of ferrous ion, 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA), and 3'-p-(aminophenyl) fluorescein, respectively. Reduced glutathione, total iron levels and photoreceptor cell death were also measured. Two genes related to iron metabolism, transferrin receptor 1 (TfR1) and H ferritin (HFt), were quantified by RT-PCR. The effects of ferrous ion on cell death and hydroxyl radical production were determined by treatment with a ferrous ion chelating agent, 2,2'-bipyridyl. We found that the ferrous ion level decreased with light exposure in the short time frame, whereas it was upregulated during a 6-h light exposure. Total iron, ROS, cell death rate, and expression of TfR and HFt genes were significantly increased in a time-dependent manner in 661 W cells exposed to light. Chelation with 2,2'-bipyridyl reduced the level of hydroxyl radicals and protected against light-induced cell death. These results suggest that light exposure decreases ferrous ion levels and enhances iron uptake in photoreceptor cells. Ferrous ion may be involved in light-induced photoreceptor cell death through production of hydroxyl radicals. PMID:25447561

  1. A neuroanatomical and physiological study of the non-image forming visual system of the cone-rod homeobox gene (Crx) knock out mouse

    DEFF Research Database (Denmark)

    Rovsing, Louise; Rath, Martin F; Lund-Andersen, Casper; Klein, David C; Møller, Morten

    2010-01-01

    The anatomy and physiology of the non-image forming visual system was investigated in a visually blind cone-rod homeobox gene (Crx) knock-out mouse (Crx(-)(/)(-)), which lacks the outer segments of the photoreceptors. We show that the suprachiasmatic nuclei (SCN) in the Crx(-/-) mouse exhibit...

  2. Retinal dysfunction, photoreceptor protein dysregulation and neuronal remodelling in the R6/1 mouse model of Huntington's disease.

    Science.gov (United States)

    Batcha, Abrez Hussain; Greferath, Una; Jobling, Andrew I; Vessey, Kirstan A; Ward, Michelle M; Nithianantharajah, Jess; Hannan, Anthony J; Kalloniatis, Michael; Fletcher, Erica L

    2012-03-01

    Huntington's disease (HD) is a progressive neurological disease characterised by motor dysfunction, cognitive impairment and personality changes. Previous work in HD patients and animal models of the disease has also highlighted retinal involvement. This study characterised the changes in retinal structure and function early within the progression of disease using the R6/1 mouse model of HD. The retinal phenotype was observed to occur at the same time in the disease process as other neurological deficits such as motor dysfunction (by 13 weeks of age). There was a specific functional deficit in cone response to the electroretinogram and using immunocytochemical techniques, this dysfunction was found to be likely due to a progressive and complete loss of cone opsin and transducin protein expression by 20 weeks of age. In addition, there was an increase in Müller cell gliosis and the presence of ectopic rod photoreceptor terminals. This retinal remodelling is also observed in downstream neurons, namely the rod and cone bipolar cells. While R6/1 mice exhibit significant retinal pathology simultaneously with other more classical HD alterations, this doesn't lead to extensive cell loss. These findings suggest that in HD, cone photoreceptors are initially targeted, possibly via dysregulation of protein expression or trafficking and that this process is subsequently accompanied by increased retinal stress and neuronal remodelling also involving the rod pathway. As retinal structure and connectivity are well characterised, the retina may provide a useful model tissue in which to characterise the mechanisms important in the development of neuronal pathology in HD. PMID:22198376

  3. Hessian-LoG filtering for enhancement and detection of photoreceptor cells in adaptive optics retinal images.

    Science.gov (United States)

    Lazareva, Anfisa; Liatsis, Panos; Rauscher, Franziska G

    2016-01-01

    Automated analysis of retinal images plays a vital role in the examination, diagnosis, and prognosis of healthy and pathological retinas. Retinal disorders and the associated visual loss can be interpreted via quantitative correlations, based on measurements of photoreceptor loss. Therefore, it is important to develop reliable tools for identification of photoreceptor cells. In this paper, an automated algorithm is proposed, based on the use of the Hessian-Laplacian of Gaussian filter, which allows enhancement and detection of photoreceptor cells. The performance of the proposed technique is evaluated on both synthetic and high-resolution retinal images, in terms of packing density. The results on the synthetic data were compared against ground truth as well as cone counts obtained by the Li and Roorda algorithm. For the synthetic datasets, our method showed an average detection accuracy of 98.8%, compared to 93.9% for the Li and Roorda approach. The packing density estimates calculated on the retinal datasets were validated against manual counts and the results obtained by a proprietary software from Imagine Eyes and the Li and Roorda algorithm. Among the tested methods, the proposed approach showed the closest agreement with manual counting. PMID:26831589

  4. Photoreceptor IRBP prevents light induced injury.

    Science.gov (United States)

    Sun, Zhongcui; Zhang, Meng; Liu, Wei; Tian, Jie; Xu, Gezhi

    2016-01-01

    Interphotoreceptor retinoid-binding protein (IRBP) is a classic inducer of experimental autoimmune uveoretinitis (EAU). Although IRBP causes neuronal loss in susceptible animals, resistant animals such as Sprague-Dawley (SPD) rats can benefit from the evoked protective autoimmune responses. The aim of the present study was to analyze the neuroprotective effects of IRBP against light-induced photoreceptor degeneration. We immunized 75 male SPD rats with IRBP and the rats were then exposed to blue light for 24 hours (IRBP group). Seventy five rats were included in the control group. We found that the number of apoptotic cells in the outer nuclear layer (ONL) peaked on 1 day after light exposure, and the ONL thickness decreased significantly on day 3. OX42-positive cells appeared in the ONL immediately after light exposure, and their number peaked on day 3, and changed from resting ramified cells to activated amoeboid cells. Compared with the control group (n=75), the IRBP group showed less apoptotic cells, a thicker ONL, and reduced expression of tumor necrosis factor-alpha. These outcomes indicate the IRPB might protect retinal photoreceptors against light-induced injury. PMID:27100484

  5. Electrophysiology Activity of the Photoreceptors Using Photopic Adapted Full-Field Electroretinogram in Young Malay Adults

    Directory of Open Access Journals (Sweden)

    Ai-Hong Chen

    2013-08-01

    Full Text Available The full-field electroretinogram (ffERG was used as an electrophysiological test of retinal function. The electrophysiology activity of the photoreceptors in the retina was investigated using photopic adapted full-field electroretinogram (ffERG in a sample of Malay ethnic (Melayu, (mean 21.72 ± 0.88 years old. About 10 minutes room illumination of photopic adaptation was used, single flashes of 3 cd.s.m-2 presented until 4 similar artifact free ERG waveforms, and 30 Hz flickers ERG was averaged based on 15 sweeps of 250 milliseconds (ms duration, which based on the International Society of Clinical Electrophysiology of Vision (ISCEV 2008 ERG Standard. The mean, standard deviation and median of amplitude (uV of cone a-wave (-30.73 ± 12.49, -29.22 and cone b-wave (119.26 ± 37.76, 119.45, and the latency time (ms of cone a-wave (14.30 ± 1.15, 14.50 and cone b-wave (30.02 ± 0.98, 30.00, 30 Hz peak amplitude (97.12 ± 28.63, 86.51, and latency time for peak (26.27 ± 1.77, 26.00 and trough (13.13 ± 2.10, 13.00 respectively were shown in descriptive data. The normal value of young Malay adults as the baseline data for Malay population and comparable to other population around the world is important for ffERG practical.

  6. Resurrecting the Dead Cone

    CERN Document Server

    Maltoni, Fabio; Thaler, Jesse

    2016-01-01

    The dead cone is a well-known effect in gauge theories, where radiation from a charged particle of mass m and energy E is suppressed within an angular size of m/E. This effect is universal as it does not depend on the spin of the particle nor on the nature of the gauge interaction. It is challenging to directly measure the dead cone at colliders, however, since the region of suppressed radiation either is too small to be resolved or is filled by the decay products of the massive particle. In this paper, we propose to use jet substructure techniques to expose the dead cone effect in the strong-force radiation pattern around boosted top quarks at the Large Hadron Collider. Our study shows that with 300/fb of 13-14 TeV collision data, ATLAS and CMS could obtain the first direct evidence of the dead cone effect and test its basic features.

  7. Two temporal functions of Glass: Ommatidium patterning and photoreceptor differentiation.

    Science.gov (United States)

    Liang, Xulong; Mahato, Simpla; Hemmerich, Chris; Zelhof, Andrew C

    2016-06-01

    Much progress has been made in elucidating the molecular networks required for specifying retinal cells, including photoreceptors, but the downstream mechanisms that maintain identity and regulate differentiation remain poorly understood. Here, we report that the transcription factor Glass has a dual role in establishing a functional Drosophila eye. Utilizing conditional rescue approaches, we confirm that persistent defects in ommatidium patterning combined with cell death correlate with the overall disruption of eye morphology in glass mutants. In addition, we reveal that Glass exhibits a separable role in regulating photoreceptor differentiation. In particular, we demonstrate the apparent loss of glass mutant photoreceptors is not only due to cell death but also a failure of the surviving photoreceptors to complete differentiation. Moreover, the late reintroduction of Glass in these developmentally stalled photoreceptors is capable of restoring differentiation in the absence of correct ommatidium patterning. Mechanistically, transcription profiling at the time of differentiation reveals that Glass is necessary for the expression of many genes implicated in differentiation, i.e. rhabdomere morphogenesis, phototransduction, and synaptogenesis. Specifically, we show Glass directly regulates the expression of Pph13, which encodes a transcription factor necessary for opsin expression and rhabdomere morphogenesis. Finally, we demonstrate the ability of Glass to choreograph photoreceptor differentiation is conserved between Drosophila and Tribolium, two holometabolous insects. Altogether, our work identifies a fundamental regulatory mechanism to generate the full complement of cells required for a functional rhabdomeric visual system and provides a critical framework to investigate the basis of differentiation and maintenance of photoreceptor identity. PMID:27105580

  8. Understanding the changes of cone reflectance in adaptive optics flood illumination retinal images over three years

    Science.gov (United States)

    Mariotti, Letizia; Devaney, Nicholas; Lombardo, Giuseppe; Lombardo, Marco

    2016-01-01

    Although there is increasing interest in the investigation of cone reflectance variability, little is understood about its characteristics over long time scales. Cone detection and its automation is now becoming a fundamental step in the assessment and monitoring of the health of the retina and in the understanding of the photoreceptor physiology. In this work we provide an insight into the cone reflectance variability over time scales ranging from minutes to three years on the same eye, and for large areas of the retina (≥ 2.0 × 2.0 degrees) at two different retinal eccentricities using a commercial adaptive optics (AO) flood illumination retinal camera. We observed that the difference in reflectance observed in the cones increases with the time separation between the data acquisitions and this may have a negative impact on algorithms attempting to track cones over time. In addition, we determined that displacements of the light source within 0.35 mm of the pupil center, which is the farthest location from the pupil center used by operators of the AO camera to acquire high-quality images of the cone mosaic in clinical studies, does not significantly affect the cone detection and density estimation. PMID:27446708

  9. Avian influenza – Review

    OpenAIRE

    Öner, Ahmet Faik

    2007-01-01

    Recent spread of avian influenza A H5N1 virus to poultry and wild birds has increased the threat of human infections with H5N1 virus worldwide In this review the epidemiology virolgy clinical and laboratory characteristics and management of avian influenza is described The virus has demonsrated considerable pandemic potential and is the most likely candidate of next pandemic threat For pandemic preparedness stockpiling antiviral agents and vaccination are the most important intervention measu...

  10. Editorial: Avian Research

    Institute of Scientific and Technical Information of China (English)

    Yong; Wang; Guangmei; Zheng

    2014-01-01

    <正>Welcome to Avian Research!This new journal is a continuation and enhancement of Chinese Birds,which has been and continues to be sponsored by the China Ornithological Society and Beijing Forestry University.In the four years since its inception,the original journal—the only one in China focusing on avian research—has published over 130 manuscripts,with authors from all continents across the world,garnering global respect in

  11. The Retinal Pigment Epithelium: a Convenient Source of New Photoreceptor cells?

    OpenAIRE

    Shu-Zhen Wang; Run-Tao Yan

    2014-01-01

    Recent success in restoring visual function through photoreceptor replacement in mouse models of photoreceptor degeneration intensifies the need to generate or regenerate photoreceptor cells for the ultimate goal of using cell replacement therapy for blindness caused by photoreceptor degeneration. Current research on deriving new photoreceptors for replacement, as regenerative medicine in general, focuses on the use of embryonic stem cells and induced pluripotent stem (iPS) cells to generate ...

  12. Accumulation of rhodopsin in late endosomes triggers photoreceptor cell degeneration.

    OpenAIRE

    Yashodhan Chinchore; Amitavo Mitra; Dolph, Patrick J.

    2009-01-01

    Author Summary Irreversible loss of photoreceptor cells has been attributed as a cause of blindness in many retinal degenerative disorders. One such group of disorders is retinitis pigmentosa, which affects 1 in 3,000 individuals. Over 100 mutations in the light-sensing molecule rhodopsin have been identified in patients with autosomal dominant retinitis pigmentosa. These mutations affect rhodopsin transport to the outer segments of rod photoreceptor cells, rhodopsin folding, and rhodopsin en...

  13. Photoreceptor twist: a solution to the false-color problem.

    OpenAIRE

    Wehner, R; Bernard, G.D.

    1993-01-01

    In bees and many other insects the majority of photoreceptors are twisted like a corkscrew. Here we show that this structural feature of insect eyes-whose very existence was a source of dispute for several years-is necessary for reliable encoding of information about color. Light reflected from waxy plant surfaces is partially linearly polarized. Moreover, insect photoreceptor membranes are dichroic and thus sensitive to the polarized glare originating from plant surfaces. Taken together, the...

  14. Photoreceptor atrophy in acute zonal occult outer retinopathy

    DEFF Research Database (Denmark)

    Zibrandtsen, N.; Munch, I.C.; Klemp, K.;

    2008-01-01

    examined using optical coherence tomography (OCT), automated perimetry and electroretinography (ERG). Both patients demonstrated photoreceptor atrophy corresponding to partial or complete scotomata with reduced or extinct electroretinographic responses. Attenuation or complete loss of all the segments...... composing the photoreceptor layer was found by OCT. Full-field ERG revealed affection of the 30 Hz flicker responses and subnormal photopic responses in both patients and subnormal scotopic responses in case 1. Multifocal electroretinography (mERG) revealed localized outer retinal dysfunction. The field...

  15. Photoreceptor atrophy in acute zonal occult outer retinopathy

    DEFF Research Database (Denmark)

    Zibrandtsen, N.; Munch, I.C.; Klemp, K.;

    2008-01-01

    appearance were examined using optical coherence tomography (OCT), automated perimetry and electroretinography (ERG). RESULTS: Both patients demonstrated photoreceptor atrophy corresponding to partial or complete scotomata with reduced or extinct electroretinographic responses. Attenuation or complete loss...... of all the segments composing the photoreceptor layer was found by OCT. Full-field ERG revealed affection of the 30 Hz flicker responses and subnormal photopic responses in both patients and subnormal scotopic responses in case 1. Multifocal electroretinography (mERG) revealed localized outer retinal...

  16. Quantitative Analysis of Synaptic Release at the Photoreceptor Synapse

    OpenAIRE

    Duncan, Gabriel; Rabl, Katalin; Gemp, Ian; Heidelberger, Ruth; Thoreson, Wallace B.

    2010-01-01

    Exocytosis from the rod photoreceptor is stimulated by submicromolar Ca2+ and exhibits an unusually shallow dependence on presynaptic Ca2+. To provide a quantitative description of the photoreceptor Ca2+ sensor for exocytosis, we tested a family of conventional and allosteric computational models describing the final Ca2+-binding steps leading to exocytosis. Simulations were fit to two measures of release, evoked by flash-photolysis of caged Ca2+: exocytotic capacitance changes from individua...

  17. Retinal Degeneration Slow (RDS) Glycosylation Plays a Role in Cone Function and in the Regulation of RDS·ROM-1 Protein Complex Formation.

    Science.gov (United States)

    Stuck, Michael W; Conley, Shannon M; Naash, Muna I

    2015-11-13

    The photoreceptor-specific glycoprotein retinal degeneration slow (RDS, also called PRPH2) is necessary for the formation of rod and cone outer segments. Mutations in RDS cause rod and cone-dominant retinal disease, and it is well established that both cell types have different requirements for RDS. However, the molecular mechanisms for this difference remain unclear. Although RDS glycosylation is highly conserved, previous studies have revealed no apparent function for the glycan in rods. In light of the highly conserved nature of RDS glycosylation, we hypothesized that it is important for RDS function in cones and could underlie part of the differential requirement for RDS in the two photoreceptor subtypes. We generated a knockin mouse expressing RDS without the N-glycosylation site (N229S). Normal levels of RDS and the unglycosylated RDS binding partner rod outer segment membrane protein 1 (ROM-1) were found in N229S retinas. However, cone electroretinogram responses were decreased by 40% at 6 months of age. Because cones make up only 3-5% of photoreceptors in the wild-type background, N229S mice were crossed into the nrl(-/-) background (in which all rods are converted to cone-like cells) for biochemical analysis. In N229S/nrl(-/-) retinas, RDS and ROM-1 levels were decreased by ~60% each. These data suggest that glycosylation of RDS is required for RDS function or stability in cones, a difference that may be due to extracellular versus intradiscal localization of the RDS glycan in cones versus rods. PMID:26420485

  18. Visual ecology and potassium conductances of insect photoreceptors.

    Science.gov (United States)

    Frolov, Roman; Immonen, Esa-Ville; Weckström, Matti

    2016-04-01

    Voltage-activated potassium channels (Kv channels) in the microvillar photoreceptors of arthropods are responsible for repolarization and regulation of photoreceptor signaling bandwidth. On the basis of analyzing Kv channels in dipteran flies, it was suggested that diurnal, rapidly flying insects predominantly express sustained K(+) conductances, whereas crepuscular and nocturnally active animals exhibit strongly inactivating Kv conductances. The latter was suggested to function for minimizing cellular energy consumption. In this study we further explore the evolutionary adaptations of the photoreceptor channelome to visual ecology and behavior by comparing K(+) conductances in 15 phylogenetically diverse insects, using patch-clamp recordings from dissociated ommatidia. We show that rapid diurnal flyers such as the blowfly (Calliphora vicina) and the honeybee (Apis mellifera) express relatively large noninactivating Kv conductances, conforming to the earlier hypothesis in Diptera. Nocturnal and/or slow-moving species do not in general exhibit stronger Kv conductance inactivation in the physiological membrane voltage range, but the photoreceptors in species that are known to rely more on vision behaviorally had higher densities of sustained Kv conductances than photoreceptors of less visually guided species. No statistically significant trends related to visual performance could be identified for the rapidly inactivating Kv conductances. Counterintuitively, strong negative correlations were observed between photoreceptor capacitance and specific membrane conductance for both sustained and inactivating fractions of Kv conductance, suggesting insignificant evolutionary pressure to offset negative effects of high capacitance on membrane filtering with increased conductance. PMID:26864762

  19. The Bird of Time: Cognition and the Avian Biological Clock

    Directory of Open Access Journals (Sweden)

    Vincent Michael Cassone

    2012-03-01

    Full Text Available Avian behavior and physiology are embedded in time at many levels of biological organization. Biological clock function in birds is critical for sleep/wake cycles, but may also regulate the acquisition of place memory, learning of song from tutors, social integration and time-compensated navigation. This relationship has two major implications. First, mechanisms of the circadian clock should be linked in some way to the mechanisms of all these behaviors. How is not yet clear, and evidence that the central clock has effects is piecemeal. Second, selection acting on characters that are linked to the circadian clock should influence aspects of the clock mechanism itself. Little evidence exists for this in birds, but there have been few attempts to assess this idea. At its core, the avian circadian clock is a multi-oscillator system comprising the pineal gland, the retinae and the avian homologues of the suprachiasmatic nuclei, whose mutual interactions ensure coordinated physiological functions, which are in turn synchronized to ambient light cycles via encephalic, pineal and retinal photoreceptors. At the molecular level, avian biological clocks comprise a genetic network of positive elements clock and bmal1 whose interactions with the negative elements period2, period3 and the cryptochromes form an oscillatory feedback loop that circumnavigates the 24 hrs of the day. We assess the possibilities for dual integration of the clock with time-dependent cognitive processes. Closer examination of the molecular, physiological, and behavioral elements of the circadian system would place birds at a very interesting fulcrum in the neurobiology of time in learning, memory and navigation. 

  20. In the Limelight: Photoreceptors in Cyanobacteria.

    Science.gov (United States)

    Bhaya, Devaki

    2016-01-01

    Certain cyanobacteria look green if grown in red light and vice versa. This dramatic color change, called complementary chromatic adaptation (CCA), is caused by alterations of the major colored light-harvesting proteins. A major controller of CCA is the cyanobacteriochrome (CBCR) RcaE, a red-green reversible photoreceptor that triggers a complex signal transduction pathway. Now, a new study demonstrates that CCA is also modulated by DpxA, a CBCR that senses yellow and teal (greenish blue) light. DpxA acts to expand the range of wavelengths that can impact CCA, by fine-tuning the process. This dual control of CCA might positively impact the fitness of cells growing in the shade of competing algae or in a water column where light levels and spectral quality change gradually with depth. This discovery adds to the growing number of light-responsive phenomena controlled by multiple CBCRs. Furthermore, the diverse CBCRs which are exclusively found in cyanobacteria have significant biotechnological potential. PMID:27353763

  1. In the Limelight: Photoreceptors in Cyanobacteria

    Science.gov (United States)

    2016-01-01

    ABSTRACT Certain cyanobacteria look green if grown in red light and vice versa. This dramatic color change, called complementary chromatic adaptation (CCA), is caused by alterations of the major colored light-harvesting proteins. A major controller of CCA is the cyanobacteriochrome (CBCR) RcaE, a red-green reversible photoreceptor that triggers a complex signal transduction pathway. Now, a new study demonstrates that CCA is also modulated by DpxA, a CBCR that senses yellow and teal (greenish blue) light. DpxA acts to expand the range of wavelengths that can impact CCA, by fine-tuning the process. This dual control of CCA might positively impact the fitness of cells growing in the shade of competing algae or in a water column where light levels and spectral quality change gradually with depth. This discovery adds to the growing number of light-responsive phenomena controlled by multiple CBCRs. Furthermore, the diverse CBCRs which are exclusively found in cyanobacteria have significant biotechnological potential. PMID:27353763

  2. Discretized light cone quantization

    International Nuclear Information System (INIS)

    The method of discretized light-cone quantization is reviewed in simple terms. Emphasis is put on how one should define a Hamiltonian, and on periodic boundary conditions. Some numerical results for one and for three space dimensions are compiled. The challenges and the virtues of the method are discussed in short. (orig.)

  3. Dynamic Cone Penetrometer (DCP)

    OpenAIRE

    Siddiki, Nayyar Zia

    2012-01-01

    Recent advances in the performance and monitoring of earthwork compaction can lead to faster, more consistent and more cost-effective roadway construction. Learn about INDOT’s progress towards broader implementation of the light-weight deflectometer, dynamic cone penetrometer and intelligent compaction technologies.

  4. Common transcriptional mechanisms for visual photoreceptor cell differentiation among Pancrustaceans.

    Directory of Open Access Journals (Sweden)

    Simpla Mahato

    2014-07-01

    Full Text Available A hallmark of visual rhabdomeric photoreceptors is the expression of a rhabdomeric opsin and uniquely associated phototransduction molecules, which are incorporated into a specialized expanded apical membrane, the rhabdomere. Given the extensive utilization of rhabdomeric photoreceptors in the eyes of protostomes, here we address whether a common transcriptional mechanism exists for the differentiation of rhabdomeric photoreceptors. In Drosophila, the transcription factors Pph13 and Orthodenticle (Otd direct both aspects of differentiation: rhabdomeric opsin transcription and rhabdomere morphogenesis. We demonstrate that the orthologs of both proteins are expressed in the visual systems of the distantly related arthropod species Tribolium castaneum and Daphnia magna and that their functional roles are similar in these species. In particular, we establish that the Pph13 homologs have the ability to bind a subset of Rhodopsin core sequence I sites and that these sites are present in key phototransduction genes of both Tribolium and Daphnia. Furthermore, Pph13 and Otd orthologs are capable of executing deeply conserved functions of photoreceptor differentiation as evidenced by the ability to rescue their respective Drosophila mutant phenotypes. Pph13 homologs are equivalent in their ability to direct both rhabdomere morphogenesis and opsin expression within Drosophila, whereas Otd paralogs demonstrate differential abilities to regulate photoreceptor differentiation. Finally, loss-of-function analyses in Tribolium confirm the conserved requirement of Pph13 and Otd in regulating both rhabdomeric opsin transcription and rhabdomere morphogenesis. Taken together, our data identify components of a regulatory framework for rhabdomeric photoreceptor differentiation in Pancrustaceans, providing a foundation for defining ancestral regulatory modules of rhabdomeric photoreceptor differentiation.

  5. Requirement for zebrafish ataxin-7 in differentiation of photoreceptors and cerebellar neurons.

    Directory of Open Access Journals (Sweden)

    Constantin Yanicostas

    Full Text Available The expansion of a polyglutamine (polyQ tract in the N-terminal region of ataxin-7 (atxn7 is the causative event in spinocerebellar ataxia type 7 (SCA7, an autosomal dominant neurodegenerative disorder mainly characterized by progressive, selective loss of rod-cone photoreceptors and cerebellar Purkinje and granule cells. The molecular and cellular processes underlying this restricted neuronal vulnerability, which contrasts with the broad expression pattern of atxn7, remains one of the most enigmatic features of SCA7, and more generally of all polyQ disorders. To gain insight into this specific neuronal vulnerability and achieve a better understanding of atxn7 function, we carried out a functional analysis of this protein in the teleost fish Danio rerio. We characterized the zebrafish atxn7 gene and its transcription pattern, and by making use of morpholino-oligonucleotide-mediated gene inactivation, we analysed the phenotypes induced following mild or severe zebrafish atxn7 depletion. Severe or nearly complete zebrafish atxn7 loss-of-function markedly impaired embryonic development, leading to both early embryonic lethality and severely deformed embryos. More importantly, in relation to SCA7, moderate depletion of the protein specifically, albeit partially, prevented the differentiation of both retina photoreceptors and cerebellar Purkinje and granule cells. In addition, [1-232] human atxn7 fragment rescued these phenotypes showing strong function conservation of this protein through evolution. The specific requirement for zebrafish atxn7 in the proper differentiation of cerebellar neurons provides, to our knowledge, the first in vivo evidence of a direct functional relationship between atxn7 and the differentiation of Purkinje and granule cells, the most crucial neurons affected in SCA7 and most other polyQ-mediated SCAs. These findings further suggest that altered protein function may play a role in the pathophysiology of the disease, an

  6. Avian influenza (fowl plague)

    Science.gov (United States)

    Avian influenza (AI) viruses infect domestic poultry and wild birds. In domestic poultry, AI viruses are typically of low pathogenicity (LP) causing subclinical infections, respiratory disease or drops in egg production. However, a few AI viruses cause severe systemic disease with high mortality; ...

  7. Avian pox in ostriches.

    Science.gov (United States)

    Allwright, D M; Burger, W P; Geyer, A; Wessles, J

    1994-03-01

    Nodular cutaneous and diphtheric oral lesions, resembling avian pox were observed in 2 flocks of young ostrich chicks. Typical eosinophilic intracytoplasmic inclusion bodies were seen in histological sections and a pox virus was isolated from the lesions. A commercial fowl pox vaccine was used to protect young ostriches in the field. PMID:7745588

  8. Biophysical mechanism of transient retinal phototropism in rod photoreceptors

    Science.gov (United States)

    Zhao, Xiaohui; Thapa, Damber; Wang, Benquan; Gai, Shaoyan; Yao, Xincheng

    2016-03-01

    Oblique light stimulation evoked transient retinal phototropism (TRP) has been recently detected in frog and mouse retinas. High resolution microscopy of freshly isolated retinas indicated that the TRP is predominated by rod photoreceptors. Comparative confocal microscopy and optical coherence tomography (OCT) revealed that the TRP predominantly occurred from the photoreceptor outer segment (OS). However, biophysical mechanism of rod OS change is still unknown. In this study, frog retinal slices, which open a cross section of retinal photoreceptor and other functional layers, were used to test the effect of light stimulation on rod OS. Near infrared light microscopy was employed to monitor photoreceptor changes in retinal slices stimulated by a rectangular-shaped visible light flash. Rapid rod OS length change was observed after the stimulation delivery. The magnitude and direction of the rod OS change varied with the position of the rods within the stimulated area. In the center of stimulated region the length of the rod OS shrunk, while in the peripheral region the rod OS tip swung towards center region in the plane perpendicular to the incident stimulus light. Our experimental result and theoretical analysis suggest that the observed TRP may reflect unbalanced disc-shape change due to localized pigment bleaching. Further investigation is required to understand biochemical mechanism of the observed rod OS kinetics. Better study of the TRP may provide a noninvasive biomarker to enable early detection of age-related macular degeneration (AMD) and other diseases that are known to produce retinal photoreceptor dysfunctions.

  9. Photoreceptor spectral sensitivity in the bumblebee, Bombus impatiens (Hymenoptera: Apidae.

    Directory of Open Access Journals (Sweden)

    Peter Skorupski

    Full Text Available The bumblebee Bombus impatiens is increasingly used as a model in comparative studies of colour vision, or in behavioural studies relying on perceptual discrimination of colour. However, full spectral sensitivity data on the photoreceptor inputs underlying colour vision are not available for B. impatiens. Since most known bee species are trichromatic, with photoreceptor spectral sensitivity peaks in the UV, blue and green regions of the spectrum, data from a related species, where spectral sensitivity measurements have been made, are often applied to B impatiens. Nevertheless, species differences in spectral tuning of equivalent photoreceptor classes may result in peaks that differ by several nm, which may have small but significant effects on colour discrimination ability. We therefore used intracellular recording to measure photoreceptor spectral sensitivity in B. impatiens. Spectral peaks were estimated at 347, 424 and 539 nm for UV, blue and green receptors, respectively, suggesting that this species is a UV-blue-green trichromat. Photoreceptor spectral sensitivity peaks are similar to previous measurements from Bombus terrestris, although there is a significant difference in the peak sensitivity of the blue receptor, which is shifted in the short wave direction by 12-13 nm in B. impatiens compared to B. terrestris.

  10. Avian dark cells

    Science.gov (United States)

    Hara, J.; Plymale, D. R.; Shepard, D. L.; Hara, H.; Garry, Robert F.; Yoshihara, T.; Zenner, Hans-Peter; Bolton, M.; Kalkeri, R.; Fermin, Cesar D.

    2002-01-01

    Dark cells (DCs) of mammalian and non-mammalian species help to maintain the homeostasis of the inner ear fluids in vivo. Although the avian cochlea is straight and the mammalian cochlea is coiled, no significant difference in the morphology and/or function of mammalian and avian DCs has been reported. The mammalian equivalent of avian DCs are marginal cells and are located in the stria vascularis along a bony sheet. Avian DCs hang free from the tegmentum vasculosum (TV) of the avian lagena between the perilymph and endolymph. Frame averaging was used to image the fluorescence emitted by several fluorochromes applied to freshly isolated dark cells (iDCs) from chickens (Gallus domesticus) inner ears. The viability of iDCs was monitored via trypan blue exclusion at each isolation step. Sodium Green, BCECF-AM, Rhodamine 123 and 9-anthroyl ouabain molecules were used to test iDC function. These fluorochromes label iDCs ionic transmembrane trafficking function, membrane electrogenic potentials and Na+/K+ ATPase pump's activity. Na+/K+ ATPase pump sites, were also evaluated by the p-nitrophenyl phosphatase reaction. These results suggest that iDCs remain viable for several hours after isolation without special culturing requirements and that the number and functional activity of Na+/K+ ATPase pumps in the iDCs were indistinguishable from in vivo DCs. Primary cultures of freshly iDCs were successfully maintained for 28 days in plastic dishes with RPMI 1640 culture medium. The preparation of iDCs overcomes the difficulty of DCs accessability in vivo and the unavoidable contamination that rupturing the inner ear microenvironments induces.

  11. Ejecta evolution during cone impact

    KAUST Repository

    Marston, Jeremy

    2014-07-07

    We present findings from an experimental investigation into the impact of solid cone-shaped bodies onto liquid pools. Using a variety of cone angles and liquid physical properties, we show that the ejecta formed during the impact exhibits self-similarity for all impact speeds for very low surface tension liquids, whilst for high-surface tension liquids similarity is only achieved at high impact speeds. We find that the ejecta tip can detach from the cone and that this phenomenon can be attributed to the air entrainment phenomenon. We analyse of a range of cone angles, including some ogive cones, and impact speeds in terms of the spatiotemporal evolution of the ejecta tip. Using superhydrophobic cones, we also examine the entry of cones which entrain an air layer.

  12. 網膜視細胞の平面配列解析のための視細胞位置決定および同定法の開発(橋本葉子教授退任記念論文集)

    OpenAIRE

    神山, 暢夫; 王, 軍; 橋本, 葉子; KOUYAMA, Nobuo; WANG, Jun; HASHIMOTO, Yoko

    1997-01-01

    The topographical array structures of photoreceptors were studied in avian retina. Each cone in avian retina has an oil droplet with colors distinctive to the types of cones. We have developed a procedure to determine the coordinates of the gravity centers of the cones, and to identify the types of cones using the particular absorption spectra of their oil droplets. The absorbance of monochromatic light was obtained through the measurements of the optical density of grayscale images taken by ...

  13. Cones and craters on Mount Pavagadh, Deccan Traps: Rootless cones?

    Indian Academy of Sciences (India)

    Hetu C Sheth; George Mathew; Kanchan Pande; Soumen Mallick; Balaram Jena

    2004-12-01

    Rootless cones, also (erroneously) called pseudocraters, form due to explosions that ensue when a lava flow enters a surface water body, ice, or wet ground. They do not represent primary vents connected by vertical conduits to a subsurface magma source. Rootless cones in Iceland are well studied. Cones on Mars, morphologically very similar to Icelandic rootless cones, have also been suggested to be rootless cones formed by explosive interaction between surface lava flows and ground ice. We report here a group of gentle cones containing nearly circular craters from Mount Pavagadh, Deccan volcanic province, and suggest that they are rootless cones. They are very similar morphologically to the rootless cones of the type locality of Mý vatn in northeastern Iceland. A group of three phreatomagmatic craters was reported in 1998 from near Jabalpur in the northeastern Deccan, and these were suggested to be eroded cinder cones. A recent geophysical study of the Jabalpur craters does not support the possibility that they are located over volcanic vents. They could also be rootless cones. Many more probably exist in the Deccan, and volcanological studies of the Deccan are clearly of value in understanding planetary basaltic volcanism.

  14. Avian Influenza A Virus Infections in Humans

    Science.gov (United States)

    ... Past Newsletters Avian Influenza A Virus Infections in Humans Language: English Español Recommend on Facebook Tweet ... A Viruses Avian Influenza A Virus Infections in Humans Although avian influenza A viruses usually do not ...

  15. Light cone matrix product

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, Matthew B [Los Alamos National Laboratory

    2009-01-01

    We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, the behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.

  16. Successful arrest of photoreceptor and vision loss expands the therapeutic window of retinal gene therapy to later stages of disease.

    Science.gov (United States)

    Beltran, William A; Cideciyan, Artur V; Iwabe, Simone; Swider, Malgorzata; Kosyk, Mychajlo S; McDaid, Kendra; Martynyuk, Inna; Ying, Gui-Shuang; Shaffer, James; Deng, Wen-Tao; Boye, Sanford L; Lewin, Alfred S; Hauswirth, William W; Jacobson, Samuel G; Aguirre, Gustavo D

    2015-10-27

    Inherited retinal degenerations cause progressive loss of photoreceptor neurons with eventual blindness. Corrective or neuroprotective gene therapies under development could be delivered at a predegeneration stage to prevent the onset of disease, as well as at intermediate-degeneration stages to slow the rate of progression. Most preclinical gene therapy successes to date have been as predegeneration interventions. In many animal models, as well as in human studies, to date, retinal gene therapy administered well after the onset of degeneration was not able to modify the rate of progression even when successfully reversing dysfunction. We evaluated consequences of gene therapy delivered at intermediate stages of disease in a canine model of X-linked retinitis pigmentosa (XLRP) caused by a mutation in the Retinitis Pigmentosa GTPase Regulator (RPGR) gene. Spatiotemporal natural history of disease was defined and therapeutic dose selected based on predegeneration results. Then interventions were timed at earlier and later phases of intermediate-stage disease, and photoreceptor degeneration monitored with noninvasive imaging, electrophysiological function, and visual behavior for more than 2 y. All parameters showed substantial and significant arrest of the progressive time course of disease with treatment, which resulted in long-term improved retinal function and visual behavior compared with control eyes. Histology confirmed that the human RPGR transgene was stably expressed in photoreceptors and associated with improved structural preservation of rods, cones, and ON bipolar cells together with correction of opsin mislocalization. These findings in a clinically relevant large animal model demonstrate the long-term efficacy of RPGR gene augmentation and substantially broaden the therapeutic window for intervention in patients with RPGR-XLRP. PMID:26460017

  17. Accumulation of rhodopsin in late endosomes triggers photoreceptor cell degeneration.

    Directory of Open Access Journals (Sweden)

    Yashodhan Chinchore

    2009-02-01

    Full Text Available Progressive retinal degeneration is the underlying feature of many human retinal dystrophies. Previous work using Drosophila as a model system and analysis of specific mutations in human rhodopsin have uncovered a connection between rhodopsin endocytosis and retinal degeneration. In these mutants, rhodopsin and its regulatory protein arrestin form stable complexes, and endocytosis of these complexes causes photoreceptor cell death. In this study we show that the internalized rhodopsin is not degraded in the lysosome but instead accumulates in the late endosomes. Using mutants that are defective in late endosome to lysosome trafficking, we were able to show that rhodopsin accumulates in endosomal compartments in these mutants and leads to light-dependent retinal degeneration. Moreover, we also show that in dying photoreceptors the internalized rhodopsin is not degraded but instead shows characteristics of insoluble proteins. Together these data implicate buildup of rhodopsin in the late endosomal system as a novel trigger of death of photoreceptor neurons.

  18. Light Cone Current Algebra

    OpenAIRE

    Fritzsch, H.; Gell-Mann, M.

    2003-01-01

    This talk follows by a few months a talk by the same authors on nearly the same subject at the Coral Gables Conference. The ideas presented here are basically the same, but with some amplification, some change of viewpoint, and a number of new questions for the future. For our own convenience, we have transcribed the Coral Gables paper, but with an added ninth section, entitled "Problems of light cone current algebra", dealing with our present views and emphasizing research topics that requir...

  19. Squid rhodopsin and GTP-binding protein crossreact with vertebrate photoreceptor enzymes.

    OpenAIRE

    Saibil, H R; Michel-Villaz, M

    1984-01-01

    The activation of photoreceptor GTP-binding protein by rhodopsin was studied in squid photoreceptors and in crossreactions between the squid and bovine proteins. Turbidity changes were observed in the far-red after photoexcitation of rhodopsin with brief flashes and were used to probe interactions between photoreceptor membrane suspensions and soluble protein extracts. Our findings are squid photoreceptors contain a GTP-binding protein detectable by light- and GTP-sensitive turbidity changes ...

  20. An overview on avian influenza

    OpenAIRE

    Nelson Rodrigo da Silva Martins

    2012-01-01

    Avian influenza (AI) is considered an exotic disease in the Brazilian poultry industry, according to the National Avian Health Program (PNSA), with permanent monitoring of domestic, exotic and native avian species. Brazil presents privileged environmental conditions of reduced risk. In addition, all commercial poultry and conservation holdings are registered in state or national inventories and geographically located (GPS) for health control. Poultry health standards are adopted for the confo...

  1. Avian influenza viruses in humans.

    OpenAIRE

    Malik Peiris, J S

    2009-01-01

    Past pandemics arose from low pathogenic avian influenza (LPAI) viruses. In more recent times, highly pathogenic avian influenza (HPAI) H5N1, LPAI H9N2 and both HPAI and LPAI H7 viruses have repeatedly caused zoonotic disease in humans. Such infections did not lead to sustained human-to-human transmission. Experimental infection of human volunteers and seroepidemiological studies suggest that avian influenza viruses of other subtypes may also infect humans. Viruses of the H7 subtype appear to...

  2. SEKILAS TENTANG AVIAN INFLUENZA (AI)

    OpenAIRE

    Fauziah Elytha

    2011-01-01

    Fluburung atau Avian Influenza (AI) adalah penyakit zoonosis fatal dan menular serta dapat menginfeksi semua jenis burung, manusia, babi, kuda dan anjing, Virus Avian Influenza tipe A (hewan) dari keluarga Drthomyxoviridae telah menyerang manusia dan menyebabkan banyak korban meninggal dunia. Saat ini avian Influenza telah menjadi masalah kesehatan global yang sangat serius, termasuk di Indonesia. Sejak Juli 2005 Sampai 12 April 2006 telah ditemukan 479 kasus kumulatif dan dicurigai flu burun...

  3. Birth order dependent growth cone segregation determines synaptic layer identity in the Drosophila visual system.

    Science.gov (United States)

    Kulkarni, Abhishek; Ertekin, Deniz; Lee, Chi-Hon; Hummel, Thomas

    2016-01-01

    The precise recognition of appropriate synaptic partner neurons is a critical step during neural circuit assembly. However, little is known about the developmental context in which recognition specificity is important to establish synaptic contacts. We show that in the Drosophila visual system, sequential segregation of photoreceptor afferents, reflecting their birth order, lead to differential positioning of their growth cones in the early target region. By combining loss- and gain-of-function analyses we demonstrate that relative differences in the expression of the transcription factor Sequoia regulate R cell growth cone segregation. This initial growth cone positioning is consolidated via cell-adhesion molecule Capricious in R8 axons. Further, we show that the initial growth cone positioning determines synaptic layer selection through proximity-based axon-target interactions. Taken together, we demonstrate that birth order dependent pre-patterning of afferent growth cones is an essential pre-requisite for the identification of synaptic partner neurons during visual map formation in Drosophila. PMID:26987017

  4. The avian haemophili.

    OpenAIRE

    Blackall, P. J.

    1989-01-01

    There are four currently recognized taxa to accommodate the avian haemophili: Haemophilus paragallinarum, Pasteurella avium, Pasteurella volantium, and Pasteurella species A (the last three being formerly united as Haemophilus avium). A range of other taxa has also been recognized, but they have been neither named nor assigned to a genus. All of these various taxa, legitimate and otherwise, have the common characteristic of requiring V factor, but not X factor, for in vitro growth. Several re...

  5. BIRD FLU (AVIAN INFLUENZA)

    OpenAIRE

    Acar, Ali; Bulent BESIRBELLIOÐLU

    2005-01-01

    Avian influenza (bird flu) is a contagious disease of animals caused by influenza A viruses. These flu viruses occur naturally among birds. Actually, humans are not infected by bird flu viruses.. However, during an outbreak of bird flu among poultry, there is a possible risk to people who have contact infect birds or surface that have been contaminated with excreations from infected birds. Symptoms of bird flu in humans have ranged from typical flu-like symptoms to eye infections, pneumonia, ...

  6. Avian psychology and communication.

    OpenAIRE

    Rowe, Candy; Skelhorn, John

    2004-01-01

    The evolution of animal communication is a complex issue and one that attracts much research and debate. 'Receiver psychology' has been highlighted as a potential selective force, and we review how avian psychological processes and biases can influence the evolution and design of signals as well as the progress that has been made in testing these ideas in behavioural studies. Interestingly, although birds are a focal group for experimental psychologists and behavioural ecologists alike, the i...

  7. Avian mycoplasmosis update

    OpenAIRE

    ER Nascimento; VLA Pereira; MGF Nascimento; ML Barreto

    2005-01-01

    Avian mycoplasmas occur in a variety of bird species. The most important mycoplasmas for chickens and turkeys are Mycoplasma gallisepticum (MG), M. synoviae (MS), and M. meleagridis. Besides, M. iowe (MI) is an emerging pathogen in turkeys, but of little concern for chickens. Mycoplasmas are bacteria that lack cell wall and belong to the class Mollicutes. Although they have been considered extracellular agents, scientists admit nowadays that some of them are obligatory intracellular microorga...

  8. Applications of avian transgenesis.

    Science.gov (United States)

    Scott, Benjamin B; Velho, Tarciso A; Sim, Shuyin; Lois, Carlos

    2010-01-01

    The ability to introduce foreign DNA into the genome of an organism has proven to be one of the most powerful tools in modern biology. Methods for the manipulation of the animal genome have been developed at an impressive pace for 3 decades, but only in the past 5 years have useful tools for avian transgenesis emerged. The most efficient technique involves the use of replication-deficient lentiviral vectors to deliver foreign DNA into the avian germline. Although lentiviral-mediated transgenesis presents some constraints, progress in this area has garnered interest in both industry and academia for its potential applications in biological research, biotechnology, and agriculture. In this review we evaluate methods for the production of transgenic birds, focusing on the advantages and limitations of lentiviral-mediated transgenesis. We also provide an overview of future applications of this technology. The most exciting of these include disease-resistant transgenic poultry, genetically modified hens that produce therapeutic proteins in their eggs, and transgenic songbirds that serve as a model to study communication disorders. Finally, we discuss technological advances that will be necessary to make avian transgenesis a more versatile tool. PMID:21131712

  9. Grid attacks avian flu

    CERN Multimedia

    2006-01-01

    During April, a collaboration of Asian and European laboratories analysed 300,000 possible drug components against the avian flu virus H5N1 using the EGEE Grid infrastructure. Schematic presentation of the avian flu virus.The distribution of the EGEE sites in the world on which the avian flu scan was performed. The goal was to find potential compounds that can inhibit the activities of an enzyme on the surface of the influenza virus, the so-called neuraminidase, subtype N1. Using the Grid to identify the most promising leads for biological tests could speed up the development process for drugs against the influenza virus. Co-ordinated by CERN and funded by the European Commission, the EGEE project (Enabling Grids for E-sciencE) aims to set up a worldwide grid infrastructure for science. The challenge of the in silico drug discovery application is to identify those molecules which can dock on the active sites of the virus in order to inhibit its action. To study the impact of small scale mutations on drug r...

  10. Cubozoan genome illuminates functional diversification of opsins and photoreceptor evolution

    Czech Academy of Sciences Publication Activity Database

    Liegertová, Michaela; Pergner, Jiří; Kozmiková, Iryna; Fabian, Peter; Pombinho, António R.; Strnad, Hynek; Pačes, Jan; Vlček, Čestmír; Bartůněk, Petr; Kozmik, Zbyněk

    2015-01-01

    Roč. 5, Jul 8 (2015). ISSN 2045-2322 R&D Projects: GA ČR GAP305/10/2141; GA MŠk LO1220 Institutional support: RVO:68378050 Keywords : Cubozoan genome * opsins * photoreceptor * evolution Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.578, year: 2014

  11. Dlic1 deficiency impairs ciliogenesis of photoreceptors by destabilizing dynein

    Institute of Scientific and Technical Information of China (English)

    Shanshan Kong; Xinrong Du; Chao Peng; Yiming Wu; Huirong Li; Xi Jin; Ling Hou

    2013-01-01

    Cytoplasmic dynein 1 is fundamentally important for transporting a variety of essential cargoes along microtubules within eukaryotic cells.However,in mammals,few mutants are available for studying the effects of defects in dynein-controlled processes in the context of the whole organism.Here,we deleted mouse Dlic1 gene encoding DLIC1,a subunit of the dynein complex.Dlic1-/-mice are viable,but display severe photoreceptor degeneration.Ablation of Dlic1 results in ectopic accumulation of outer segment (OS) proteins,and impairs OS growth and ciliogenesis of photoreceptors by interfering with Rabll-vesicle trafficking and blocking efficient OS protein transport from Golgi to the basal body.Our studies show that Dlic1 deficiency partially blocks vesicle export from endoplasmic reticulum (ER),but seems not to affect vesicle transport from the ER to Golgi.Further mechanistic study reveals that lack of Dlic1 destabilizes dynein subunits and alters the normal subcellular distribution of dynein in photoreceptors,probably due to the impaired transport function of dynein.Our results demonstrate that Dlic1 plays important roles in ciliogenesis and protein transport to the OS,and is required for photoreceptor development and survival.The Dlic1-/-mice also provide a new mouse model to study human retinal degeneration.

  12. Lateral interactions in the photoreceptor membrane: a NMR study

    International Nuclear Information System (INIS)

    The photoreceptor membrane has an exceptionally high content of polyunsaturated fatty acyl chains combined with a high amount of phosphatidyl ethanolamine. It is situated in a cell organelle, the rod outer segment, with a high biological activity in which controlable trans-membrane currents of different ions play an important role. These characteristics make it a very interesting biological membrane to search for the existence of non-bilayer structures. Therefore in this thesis a detailed study of the polymorphic phase behaviour of the rod outer segment photoreceptor lipids was undertaken, concerning modulation of the polymorphic phase behaviour of photoreceptor membrane lipids by divalent cations and temperature, polymorphism of the individual phospholipid classes phosphatidylethanolamine and phosphatidylserine and effects of cholesterol, bilayer stabilization by (rhod)opsin. Morphologically intact rod outer segment possesses a large magnetic anisotropy. This property is used to obtain 31P-NMR of oriented photoreceptor membranes which allows spectral analysis and identification of individual phospholipid classes, and allows to study lateral lipid diffusion in intact disk membranes. The power of high resolution solid state 13C-NMR to study the conformation of the chromophore in rhodopsin is demonstrated. (Auth.)

  13. Intrinsic oscillatory activity arising within the electrically coupled AII amacrine-ON cone bipolar cell network is driven by voltage-gated Na + channels

    OpenAIRE

    Trenholm, S; Borowska, J; Zhang, J; Hoggarth, A; Johnson, K.; Barnes, S.; Lewis, TJ; Awatramani, GB

    2012-01-01

    In the rd1 mouse model for retinal degeneration, the loss of photoreceptors results in oscillatory activity (∼10-20 Hz) within the remnant electrically coupled network of retinal ON cone bipolar and AII amacrine cells. We tested the role of hyperpolarization-activated currents (I h), voltage-gated Na + channels and gap junctions in mediating such oscillatory activity. Blocking I h (1 mm Cs +) hyperpolarized the network and augmented activity, while antagonizing voltage-dependent Na + channels...

  14. Natural History of Cone Disease in the Murine Model of Leber Congenital Amaurosis Due to CEP290 Mutation: Determining the Timing and Expectation of Therapy

    OpenAIRE

    Boye, Shannon E.; Wei-Chieh Huang; Roman, Alejandro J.; Alexander Sumaroka; Boye, Sanford L.; Ryals, Renee C.; Olivares, Melani B.; Qing Ruan; Tucker, Budd A.; Stone, Edwin M.; Anand Swaroop; Cideciyan, Artur V.; Hauswirth, William W.; Jacobson, Samuel G.

    2014-01-01

    Background Mutations in the CEP290 (cilia-centrosomal protein 290 kDa) gene in Leber congenital amaurosis (LCA) cause early onset visual loss but retained cone photoreceptors in the fovea, which is the potential therapeutic target. A cone-only mouse model carrying a Cep290 gene mutation, rd16;Nrl−/− , was engineered to mimic the human disease. In the current study, we determined the natural history of retinal structure and function in this murine model to permit design of pre-clinical proof-o...

  15. Rapid Changes in the Translatome during the Conversion of Growth Cones to Synaptic Terminals

    Directory of Open Access Journals (Sweden)

    Kelvin Xi Zhang

    2016-02-01

    Full Text Available A common step in the formation of neural circuits is the conversion of growth cones to presynaptic terminals. Characterizing patterns of global gene expression during this process is problematic due to the cellular diversity of the brain and the complex temporal dynamics of development. Here, we take advantage of the synchronous conversion of Drosophila photoreceptor growth cones into presynaptic terminals to explore global changes in gene expression during presynaptic differentiation. Using a tandemly tagged ribosome trap (T-TRAP and RNA sequencing (RNA-seq at multiple developmental times, we observed dramatic changes in coding and non-coding RNAs with presynaptic differentiation. Marked changes in the mRNA encoding transmembrane and secreted proteins occurred preferentially. The 3′ UTRs of transcripts encoding synaptic proteins were preferentially lengthened, and these extended UTRs were preferentially enriched for sites recognized by RNA binding proteins. These data provide a rich resource for uncovering the regulatory logic underlying presynaptic differentiation.

  16. Rapid Changes in the Translatome during the Conversion of Growth Cones to Synaptic Terminals.

    Science.gov (United States)

    Zhang, Kelvin Xi; Tan, Liming; Pellegrini, Matteo; Zipursky, S Lawrence; McEwen, Jason M

    2016-02-01

    A common step in the formation of neural circuits is the conversion of growth cones to presynaptic terminals. Characterizing patterns of global gene expression during this process is problematic due to the cellular diversity of the brain and the complex temporal dynamics of development. Here, we take advantage of the synchronous conversion of Drosophila photoreceptor growth cones into presynaptic terminals to explore global changes in gene expression during presynaptic differentiation. Using a tandemly tagged ribosome trap (T-TRAP) and RNA sequencing (RNA-seq) at multiple developmental times, we observed dramatic changes in coding and non-coding RNAs with presynaptic differentiation. Marked changes in the mRNA encoding transmembrane and secreted proteins occurred preferentially. The 3' UTRs of transcripts encoding synaptic proteins were preferentially lengthened, and these extended UTRs were preferentially enriched for sites recognized by RNA binding proteins. These data provide a rich resource for uncovering the regulatory logic underlying presynaptic differentiation. PMID:26832407

  17. Avian influenza: Vaccination and control

    Science.gov (United States)

    Avian influenza (AI) is a viral disease of poultry that remains an economic threat to commercial poultry throughout the world by negatively impacting animal health and trade. Strategies to control avian influenza (AI) virus are developed to prevent, manage or eradicate the virus from the country, re...

  18. Characterization of the retinal proteome during rod photoreceptor genesis

    Directory of Open Access Journals (Sweden)

    Hecker Laura A

    2010-01-01

    Full Text Available Abstract Background The process of rod photoreceptor genesis, cell fate determination and differentiation is complex and multi-factorial. Previous studies have defined a model of photoreceptor differentiation that relies on intrinsic changes within the presumptive photoreceptor cells as well as changes in surrounding tissue that are extrinsic to the cell. We have used a proteomics approach to identify proteins that are dynamically expressed in the mouse retina during rod genesis and differentiation. Findings A series of six developmental ages from E13 to P5 were used to define changes in retinal protein expression during rod photoreceptor genesis and early differentiation. Retinal proteins were separated by isoelectric focus point and molecular weight. Gels were analyzed for changes in protein spot intensity across developmental time. Protein spots that peaked in expression at E17, P0 and P5 were picked from gels for identification. There were 239 spots that were picked for identification based on their dynamic expression during the developmental period of maximal rod photoreceptor genesis and differentiation. Of the 239 spots, 60 of them were reliably identified and represented a single protein. Ten proteins were represented by multiple spots, suggesting they were post-translationally modified. Of the 42 unique dynamically expressed proteins identified, 16 had been previously reported to be associated with the developing retina. Conclusions Our results represent the first proteomics study of the developing mouse retina that includes prenatal development. We identified 26 dynamically expressed proteins in the developing mouse retina whose expression had not been previously associated with retinal development.

  19. Cone survival and preservation of visual acuity in an animal model of retinal degeneration.

    Science.gov (United States)

    Piano, Ilaria; Novelli, Elena; Gasco, Paolo; Ghidoni, Riccardo; Strettoi, Enrica; Gargini, Claudia

    2013-06-01

    The prevention of cone loss during retinal degeneration is a major goal of most therapeutic strategies in retinal degenerative diseases. An intriguing issue in the current research in this field is to understand why a genetic mutation that affects rods eventually leads to cone death. The main objective of the present study was to investigate to what extent rescuing rods from degeneration affects the survival of cones and prevents functional impairment of the visual performance. To this purpose, we compared rod and cone viabilities by both ex vivo and in vivo determinations in the rd10 mutant mouse, a validated model of human retinitis pigmentosa. The ex vivo experiments included morphological and biochemical tests, whereas in vivo studies compared the rod-mediated scotopic with the cone-mediated photopic electroretinogram. We also determined the overall visual performance by behaviorally testing the visual acuity (VA). The electroretinogram measurements showed that the kinetics of the photopic response in rd10 mice was slowed down with respect to the age-paired wild-type at a very early stage of the disease, when rods were still present and responsive. We then tested cone viability and function under a pharmacological scheme previously shown to prolong rod survival. The treatment consisted of eye drop administration of myriocin, an inhibitor of the biosynthesis of ceramide, a powerful proapoptotic messenger. The results of biochemical, morphological and functional assays converged to show that, in treated rd10 mice cone photoreceptors, the inner retina and overall visual performance were preserved well after rod death. PMID:23551187

  20. GIT-cones and quivers

    OpenAIRE

    Ressayre, Nicolas

    2009-01-01

    In this work, we improve results about GIT-cones associated to the action of any reductive group $G$ on a projective variety $X$. These results are applied to give a short proof of a Derksen-Weyman's Theorem which parametrizes bijectively the faces of a rational cone associated to any quiver without oriented cycle.

  1. Plate Tearing by a Cone

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1997-01-01

    The present paper is concerned with steady-state plate tearing by a cone. This is a scenario where a cone is forced through a ductile metal plate with a constant lateral tip penetration in a motion in the plane of the plate. The considered process could be an idealisaton of the damage, which deve...

  2. Plate Tearing by a Cone

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1998-01-01

    The present paper is concerned with steady-state plate tearing by a cone. This is a scenario where a cone is forced through a ductile metal plate with a constant lateral tip penetration in a motion in the plane of the plate. The considered process could be an idealisation of the damage, which dev...

  3. Review on resonance cone fields

    International Nuclear Information System (INIS)

    Resonance cone fields and lower hybrid heating are reviewed in this report. The resonance cone fields were reported by Fisher and Gould, and they proposed the use of the measurement of resonance cones and structure as a diagnostic tool to determine the plasma density and electron temperature in magnetoplasma. After the resonance cone, a wave-like disturbance persists. Ohnuma et al. have measured bending, reflection and ducting of resonance cones in detail. The thermal modes in inhomogeneous magnetoplasma were seen. The reflection of thermal mode near an electron plasma frequency layer and an insulating plate has been observed. The non-linear effects of resonance cones is reported. Monochromatic electron beam produces the noise of broad band whistler mode. Lower hybrid waves have been the subject of propagation from the edge of plasma to the lower hybrid layer. Linear lower hybrid waves were studied. The lower hybrid and ion acoustic waves radiated from a point source were observed. The parametric decay of finite-extent, cold electron plasma waves was studied. The lower hybrid cone radiated from a point source going along magnetic field lines was observed. Several experimental data on the lower hybrid heating in tokamak devices have been reported. The theories on resonance cones and lower hybrid waves are introduced in this report. (Kato, T.)

  4. QCD on the light cone

    International Nuclear Information System (INIS)

    The quantization of gauge theory at fixed light-cone time τ = t - z/c provides new perspectives for solving non-perturbative problems in quantum chromodynamics. The light-cone Fock state expansion provides both a precise definition of the relativistic wavefunctions of hadrons as bound-states of quarks and gluons and a general calculus for predicting QCD processes at the amplitude level. Applications to exclusive processes and weak decay amplitudes are discussed. The problem of computing the hadronic spectrum and the corresponding light-cone wavefunctions of QCD in one space and one time dimension has been successfully reduced to the diagonalization of a discrete representation of the light-cone Hamiltonian. The problems confronting the solution of gauge theories in 3 + 1 dimensions in the light-cone quantization formalism,, including zero modes and non-perturbative renormalization, are reviewed

  5. Ordered cones and approximation

    CERN Document Server

    Keimel, Klaus

    1992-01-01

    This book presents a unified approach to Korovkin-type approximation theorems. It includes classical material on the approximation of real-valuedfunctions as well as recent and new results on set-valued functions and stochastic processes, and on weighted approximation. The results are notonly of qualitative nature, but include quantitative bounds on the order of approximation. The book is addressed to researchers in functional analysis and approximation theory as well as to those that want to applythese methods in other fields. It is largely self- contained, but the readershould have a solid background in abstract functional analysis. The unified approach is based on a new notion of locally convex ordered cones that are not embeddable in vector spaces but allow Hahn-Banach type separation and extension theorems. This concept seems to be of independent interest.

  6. The Retinal Pigment Epithelium: a Convenient Source of New Photoreceptor cells?

    Directory of Open Access Journals (Sweden)

    Shu-Zhen Wang

    2014-01-01

    Full Text Available Recent success in restoring visual function through photoreceptor replacement in mouse models of photoreceptor degeneration intensifies the need to generate or regenerate photoreceptor cells for the ultimate goal of using cell replacement therapy for blindness caused by photoreceptor degeneration. Current research on deriving new photoreceptors for replacement, as regenerative medicine in general, focuses on the use of embryonic stem cells and induced pluripotent stem (iPS cells to generate transplantable cells. Nonetheless, naturally occurring regeneration, such as wound healing, involves awakening cells at or near a wound site to produce new cells needed to heal the wound. Here we discuss the possibility of tweaking an ocular tissue, the retinal pigment epithelium (RPE, to produce photoreceptor cells in situ in the eye. Unlike the neural retina, the RPE in adult mammals maintains cell proliferation capability. Furthermore, progeny cells from RPE proliferation may differentiate into cells other than RPE. The combination of proliferation and plasticity opens a question of whether they could be channeled by a regulatory gene with pro-photoreceptor activity towards photoreceptor production. Studies using embryonic chick and transgenic mouse showed that indeed photoreceptor-like cells were produced in culture and in vivo in the eye using genedirected reprogramming of RPE cells, supporting the feasibility of using the RPE as a convenient source of new photoreceptor cells for in situ retinal repair without involving cell transplantation.

  7. Inhibition of the alternative complement pathway preserves photoreceptors after retinal injury.

    Science.gov (United States)

    Sweigard, J Harry; Matsumoto, Hidetaka; Smith, Kaylee E; Kim, Leo A; Paschalis, Eleftherios I; Okonuki, Yoko; Castillejos, Alexandra; Kataoka, Keiko; Hasegawa, Eiichi; Yanai, Ryoji; Husain, Deeba; Lambris, John D; Vavvas, Demetrios; Miller, Joan W; Connor, Kip M

    2015-07-22

    Degeneration of photoreceptors is a primary cause of vision loss worldwide, making the underlying mechanisms surrounding photoreceptor cell death critical to developing new treatment strategies. Retinal detachment, characterized by the separation of photoreceptors from the underlying retinal pigment epithelium, is a sight-threatening event that can happen in a number of retinal diseases. The detached photoreceptors undergo apoptosis and programmed necrosis. Given that photoreceptors are nondividing cells, their loss leads to irreversible visual impairment even after successful retinal reattachment surgery. To better understand the underlying disease mechanisms, we analyzed innate immune system regulators in the vitreous of human patients with retinal detachment and correlated the results with findings in a mouse model of retinal detachment. We identified the alternative complement pathway as promoting early photoreceptor cell death during retinal detachment. Photoreceptors down-regulate membrane-bound inhibitors of complement, allowing for selective targeting by the alternative complement pathway. When photoreceptors in the detached retina were removed from the primary source of oxygen and nutrients (choroidal vascular bed), the retina became hypoxic, leading to an up-regulation of complement factor B, a key mediator of the alternative pathway. Inhibition of the alternative complement pathway in knockout mice or through pharmacological means ameliorated photoreceptor cell death during retinal detachment. Our current study begins to outline the mechanism by which the alternative complement pathway facilitates photoreceptor cell death in the damaged retina. PMID:26203084

  8. Homozygous missense variant in the human CNGA3 channel causes cone-rod dystrophy.

    Science.gov (United States)

    Shaikh, Rehan S; Reuter, Peggy; Sisk, Robert A; Kausar, Tasleem; Shahzad, Mohsin; Maqsood, Muhammad I; Yousif, Ateeq; Ali, Muhammad; Riazuddin, Saima; Wissinger, Bernd; Ahmed, Zubair M

    2015-04-01

    We assessed a large consanguineous Pakistani family (PKAB157) segregating early onset low vision problems. Funduscopic and electroretinographic evaluation of affected individuals revealed juvenile cone-rod dystrophy (CRD) with maculopathy. Other clinical symptoms included loss of color discrimination, photophobia and nystagmus. Whole-exome sequencing, segregation and haplotype analyses demonstrated that a transition variant (c.955T>C; p.(Cys319Arg)) in CNGA3 co-segregated with the CRD phenotype in family PKAB157. The ability of CNGA3 channel to influx calcium in response to agonist, when expressed either alone or together with the wild-type CNGB3 subunit in HEK293 cells, was completely abolished due to p.Cys319Arg variant. Western blotting and immunolocalization studies suggest that a decreased channel density in the HEK293 cell membrane due to impaired folding and/or trafficking of the CNGA3 protein is the main pathogenic effect of the p.Cys319Arg variant. Mutant alleles of the human cone photoreceptor cyclic nucleotide-gated channel (CNGA3) are frequently associated with achromatopsia. In rare cases, variants in CNGA3 are also associated with cone dystrophy, Leber's congenital amaurosis and oligo cone trichromacy. The identification of predicted p.(Cys319Arg) missense variant in CNGA3 expands the repertoire of the known genetic causes of CRD and phenotypic spectrum of CNGA3 alleles. PMID:25052312

  9. Discussion on Photoreceptor for Negative Phototropism in Rice Roots

    Institute of Scientific and Technical Information of China (English)

    WANG Yue-xia; WANG Zhong; SUO Biao; GU Yun-jie; WANG Hui-hui; CHEN Yong-hui; DAI Yun-xia

    2007-01-01

    To properly explore the photoreceptor for the negative phototropism in rice (Oryza sativa L.) root, lights with different wavelengths were applied to investigate the effect of light quality on phototropic bending. The phototropic bending could be induced prominently by blue/ultraviolet light, whereas not by red or far-red light. The absorption spectrum of the extracted solution from rice root cap had two peaks at 350 nm and 450 nm, respectively, and the molecular weight of the 120 kD protein in the root cap under unilateral light was larger than that under the dark. It suggested that the blue light receptor might be the photoreceptor for the negative phototropism in rice root.

  10. Missed connections: photoreceptor axon seeks target neuron for synaptogenesis.

    Science.gov (United States)

    Astigarraga, Sergio; Hofmeyer, Kerstin; Treisman, Jessica E

    2010-08-01

    Extending axons must choose the appropriate synaptic target cells in order to assemble functional neural circuitry. The axons of the Drosophila color-sensitive photoreceptors R7 and R8 project as a single fascicle from each ommatidium, but their terminals are segregated into distinct layers within their target region. Recent studies have begun to reveal the molecular mechanisms that establish this projection pattern. Both homophilic adhesion molecules and specific ligand-receptor interactions make important contributions to stabilizing R7 and R8 terminals in the appropriate target layers. These cell recognition molecules are regulated by the same transcription factors that control R7 and R8 cell fates. Autocrine and repulsive signaling mechanisms prevent photoreceptor terminals from encroaching on their neighbors, preserving the spatial resolution of visual information. PMID:20434326

  11. Avian Influenza Infection Dynamics in Minor Avian Species

    OpenAIRE

    Bertran Dols, Kateri

    2013-01-01

    Avian influenza (AI) has become one of the most important challenges that ever emerged from animal reservoirs. The constant outbreaks detected worldwide in domestic and wild bird species are of concern to the economics of the poultry industry, wildlife conservation, and animal and public health. Susceptibility to AI viruses (AIVs) varies deeply among avian species, as well as their possible role as sentinels, intermediate hosts or reservoirs. To date, several experimental studies and natural ...

  12. The photochemical mechanism of a B12-dependent photoreceptor protein

    OpenAIRE

    Kutta, Roger J.; Hardman, Samantha J O; Johannissen, Linus O.; Bellina, Bruno; Messiha, Hanan L.; Ortiz-Guerrero, Juan Manuel; Elías-Arnanz, Montserrat; S Padmanabhan; Barran, Perdita; Nigel S. Scrutton; Jones, Alex R

    2015-01-01

    The coenzyme B12-dependent photoreceptor protein, CarH, is a bacterial transcriptional regulator that controls the biosynthesis of carotenoids in response to light. On binding of coenzyme B12 the monomeric apoprotein forms tetramers in the dark, which bind operator DNA thus blocking transcription. Under illumination the CarH tetramer dissociates, weakening its affinity for DNA and allowing transcription. The mechanism by which this occurs is unknown. Here we describe the photochemistry in Car...

  13. Extracellular electrical activity from the photoreceptors of midge

    Indian Academy of Sciences (India)

    A A Babrekar; G R Kulkarni; B B Nath; P B Vidyasagar

    2004-09-01

    The ontogeny of photosensitivity has been studied in a holometabolous insect, the midge Chironomus ramosus. The life cycle of midges shifts from an aquatic environment to a non-aquatic environment. Extracellular electrical activity of photoreceptor organs was recorded at larval and adult stages. We found an increase in photosensitivity as the larva metamorphosed to the adult stage. This is the first report of changes in photosensitivity during the development of any insect described in an ecological context.

  14. Does Apoptosis Regulate the Function of Retinal Photoreceptors?

    OpenAIRE

    Halaby, Reginald

    2012-01-01

    Apoptosis, or programmed cell death, is an integral component of developmental biology, embryology, and anatomy. All eukaryotic cells possess the molecular machinery necessary to execute apoptosis. However, dysregulated apoptosis in the form of too much or too little cell death results in diseases such as Alzheimer’s disease, autoimmune disorders, and cancer. It is postulated that apoptosis of the photoreceptors in the retina plays a vital role in mediating vision, and evidence is presented h...

  15. Photoreceptor degeneration, structural remodeling and glial activation: a morphological study on a genetic mouse model for pericyte deficiency.

    Science.gov (United States)

    Genové, G; Mollick, T; Johansson, K

    2014-10-24

    Interaction between pericytes and endothelial cells via platelet-derived growth factor B (PDGF-B) signaling is critical for the development of the retinal microvasculature. The PDGF-B retention motif controls the spatial distribution range of the growth factor in the vicinity of its producing endothelial cells allowing its recognition by PDGF receptor beta-(PDGFR-β)-carrying pericytes; this promotes recruitment of pericytes to the vascular basement membrane. Impairment of the PDGF-B signaling mechanism causes development of vascular abnormalities, and in the retina this consequently leads to defects in the neurological circuitry. The vascular pathology in the pdgf-b(ret/ret) (PDGF-B retention motif knockout) mouse retina has been previously reported; our study investigates the progressive neuronal defects and changes in the retinal morphology of this pericyte-deficient mouse model. Immunohistochemical analysis revealed retinal injuries to occur as early as postnatal day (P) 10 with substantial damage progressing from P15 and onward. Vascular abnormalities were apparent from P10, however, prominent neuronal defects were mostly observed from P15, beginning with the compromised integrity of the laminated retinal structure characterized by the presence of rosettes and focally distorted regions. Photoreceptor degeneration was observed by loss of both rod and cone cells, including the disassembly and altered structure of their synaptic terminals. Significant shortening of cone outer segments was observed from P10 and later stages; however, decrease in cone density was only observed at P28. Disorganization and dendrite remodeling of rod bipolar cells also added to the diminished neural and synaptic integrity. Moreover, in response to retinal injuries, Müller and microglial cells were observed to be in the reactive phenotype from P15 and onward. Such a sequence of events indicates that the pdgf-b(ret/ret) mouse model displays a short time frame between P10 and P15

  16. Nr2e3-directed transcriptional regulation of genes involved in photoreceptor development and cell-type specific phototransduction.

    Science.gov (United States)

    Haider, Neena B; Mollema, Nissa; Gaule, Meghan; Yuan, Yang; Sachs, Andrew J; Nystuen, Arne M; Naggert, Jürgen K; Nishina, Patsy M

    2009-09-01

    The retinal transcription factor Nr2e3 plays a key role in photoreceptor development and function. In this study we examine gene expression in the retina of Nr2e3(rd7/rd7) mutants with respect to wild-type control mice, to identify genes that are misregulated and hence potentially function in the Nr2e3 transcriptional network. Quantitative candidate gene real time PCR and subtractive hybridization approaches were used to identify transcripts that were misregulated in Nr2e3(rd7/rd7) mice. Chromatin immunoprecipitation assays were then used to determine which of the misregulated transcripts were direct targets of NR2E3. We identified 24 potential targets of NR2E3. In the developing retina, NR2E3 targets transcription factors such as Ror1, Rorg, and the nuclear hormone receptors Nr1d1 and Nr2c1. In the mature retina NR2E3 targets several genes including the rod specific gene Gnb1 and cone specific genes blue opsin, and two of the cone transducin subunits, Gnat2 and Gnb3. In addition, we identified 5 novel transcripts that are targeted by NR2E3. While mislocalization of proteins between rods and cones was not observed, we did observe diminished concentration of GNB1 protein in adult Nr2e3(rd7/rd7) retinas. These studies identified novel transcriptional pathways that are potentially targeted by Nr2e3 in the retina and specifically demonstrate a novel role for NR2E3 in regulating genes involved in phototransduction. PMID:19379737

  17. Chemically Induced and Light-Independent Cryptochrome Photoreceptor Activation

    Institute of Scientific and Technical Information of China (English)

    Gesa Rosenfeldt; Rafael Mu(n)oz Viana; Henning D.Mootz; Albrecht G.Von Arnim; Alfred Batschauer

    2008-01-01

    The cryptochrome photoreceptors of higher plants are dimeric proteins. Their N-terminal photosensory domain mediates dimerization, and the unique C-terminal extension (CCT) mediates signaling. We made use of the human FK506-binding protein (FKBP) that binds with high affinity to rapamycin or rapamycin analogs (rapalogs). The FKBP-rapamycin complex is recognized by another protein, FRB, thus allowing rapamycin-induced dimerization of two target proteins. Here we demonstrate by bioluminescence resonance energy transfer (BRET) assays the applicability of this regulated dimerization system to plants. Furthermore, we show that fusion proteins consisting of the C-terminal domain of Arabidopsis cryptochrome 2 fused to FKBP and FRB and coexpressed in Arabidopsis cells specifically induce the expression of cryptochrome-controlled reporter and endogenous genes in darkness upon incubation with the rapalog. These results demonstrate that the activation of cryptochrome signal transduction can be chemically induced in a dose-dependent fashion and uncoupled from the light signal, and provide the groundwork for gain-of-function experiments to study specifically the role of photoreceptors in darkness or in signaling cross-talk even under light conditions that activate members of all photoreceptor families.

  18. Quantitative analysis of synaptic release at the photoreceptor synapse.

    Science.gov (United States)

    Duncan, Gabriel; Rabl, Katalin; Gemp, Ian; Heidelberger, Ruth; Thoreson, Wallace B

    2010-05-19

    Exocytosis from the rod photoreceptor is stimulated by submicromolar Ca(2+) and exhibits an unusually shallow dependence on presynaptic Ca(2+). To provide a quantitative description of the photoreceptor Ca(2+) sensor for exocytosis, we tested a family of conventional and allosteric computational models describing the final Ca(2+)-binding steps leading to exocytosis. Simulations were fit to two measures of release, evoked by flash-photolysis of caged Ca(2+): exocytotic capacitance changes from individual rods and postsynaptic currents of second-order neurons. The best simulations supported the occupancy of only two Ca(2+) binding sites on the rod Ca(2+) sensor rather than the typical four or five. For most models, the on-rates for Ca(2+) binding and maximal fusion rate were comparable to those of other neurons. However, the off-rates for Ca(2+) unbinding were unexpectedly slow. In addition to contributing to the high-affinity of the photoreceptor Ca(2+) sensor, slow Ca(2+) unbinding may support the fusion of vesicles located at a distance from Ca(2+) channels. In addition, partial sensor occupancy due to slow unbinding may contribute to the linearization of the first synapse in vision. PMID:20483317

  19. Vector optimization with cone semilocally preinvex functions

    Directory of Open Access Journals (Sweden)

    Surjeet Kaur Suneja

    2014-01-01

    Full Text Available In this paper we introduce cone semilocally preinvex, cone semilocally quasi preinvex and cone semilocally pseudo preinvex functions and study their properties. These functions are further used to establish necessary and sufficient optimality conditions for a vector minimization problem over cones. A Mond-Weir type dual is formulated for the vector optimization problem and various duality theorems are proved.

  20. Influenza pandemics and avian flu

    OpenAIRE

    2005-01-01

    Douglas Fleming is general practitioner in a large suburban practice in Birmingham. In this article he seeks to clarify clinical issues relating to potential pandemics of influenza, including avian influenza

  1. Low Speed Avian Maneuvering Flight

    OpenAIRE

    Ros, Ivo

    2013-01-01

    Low speed avian maneuvering flight is an ecologically crucial behavior that has contributed to the explosive diversification of several avian taxa by allowing access to complex spatial environments. Negotiating a sharp aerial turn requires finely tuned interactions between an animal's sensory-motor system and its environment. My thesis work focuses on how aerodynamic forces, wing and body dynamics, and sensory feedback interact during aerial turning in the pigeon (Columba livea).

  2. Avian influenza : a review article

    OpenAIRE

    A. Yalda; EMADI H; M. Haji Abdolbaghi

    2006-01-01

    The purpose of this paper is to provides general information about avian influenza (bird flu) and specific information about one type of bird flu, called avian influenza A (H5N1), that has caused infections in birds in Asia and Europe and in human in Asia. The main materials in this report are based on the World Health Organization (WHO) , world organization for animal health (OIE) , food and agriculture organization of the united nations (FAO) information and recommendations and review of th...

  3. The Avian Development Facility

    Science.gov (United States)

    2003-01-01

    The Avian Development Facility (ADF) supports 36 eggs in two carousels, one of which rotates to provide a 1-g control for comparing to eggs grown in microgravity. The ADF was designed to incubate up to 36 Japanese quail eggs, 18 in microgravity and 18 in artificial gravity. The two sets of eggs were exposed to otherwise identical conditions, the first time this is been accomplished in space. Eggs are preserved at intervals to provide snapshots of their development for later analysis. Quails incubate in just 15 days, so they are an ideal species to be studied within the duration of space shuttle missions. Further, several investigators can use the same specimens to address different questions. The ADF originated in NASA's Shuttle Student Involvement program in the 1980s and was developed under the NASA Small Business Irnovation Research program. In late 2001, the ADF made its first flight and carried eggs used in two investigations.

  4. BIRD FLU (AVIAN INFLUENZA

    Directory of Open Access Journals (Sweden)

    Ali ACAR

    2005-12-01

    Full Text Available Avian influenza (bird flu is a contagious disease of animals caused by influenza A viruses. These flu viruses occur naturally among birds. Actually, humans are not infected by bird flu viruses.. However, during an outbreak of bird flu among poultry, there is a possible risk to people who have contact infect birds or surface that have been contaminated with excreations from infected birds. Symptoms of bird flu in humans have ranged from typical flu-like symptoms to eye infections, pneumonia, severe respiratory diseases and other severe and life-threatening complications. In such situation, people should avoid contact with infected birds or contaminated surface, and should be careful when handling and cooking poultry. [TAF Prev Med Bull 2005; 4(6.000: 345-353

  5. Mutations in CEP78 Cause Cone-Rod Dystrophy and Hearing Loss Associated with Primary-Cilia Defects.

    Science.gov (United States)

    Nikopoulos, Konstantinos; Farinelli, Pietro; Giangreco, Basilio; Tsika, Chrysanthi; Royer-Bertrand, Beryl; Mbefo, Martial K; Bedoni, Nicola; Kjellström, Ulrika; El Zaoui, Ikram; Di Gioia, Silvio Alessandro; Balzano, Sara; Cisarova, Katarina; Messina, Andrea; Decembrini, Sarah; Plainis, Sotiris; Blazaki, Styliani V; Khan, Muhammad Imran; Micheal, Shazia; Boldt, Karsten; Ueffing, Marius; Moulin, Alexandre P; Cremers, Frans P M; Roepman, Ronald; Arsenijevic, Yvan; Tsilimbaris, Miltiadis K; Andréasson, Sten; Rivolta, Carlo

    2016-09-01

    Cone-rod degeneration (CRD) belongs to the disease spectrum of retinal degenerations, a group of hereditary disorders characterized by an extreme clinical and genetic heterogeneity. It mainly differentiates from other retinal dystrophies, and in particular from the more frequent disease retinitis pigmentosa, because cone photoreceptors degenerate at a higher rate than rod photoreceptors, causing severe deficiency of central vision. After exome analysis of a cohort of individuals with CRD, we identified biallelic mutations in the orphan gene CEP78 in three subjects from two families: one from Greece and another from Sweden. The Greek subject, from the island of Crete, was homozygous for the c.499+1G>T (IVS3+1G>T) mutation in intron 3. The Swedish subjects, two siblings, were compound heterozygotes for the nearby mutation c.499+5G>A (IVS3+5G>A) and for the frameshift-causing variant c.633delC (p.Trp212Glyfs(∗)18). In addition to CRD, these three individuals had hearing loss or hearing deficit. Immunostaining highlighted the presence of CEP78 in the inner segments of retinal photoreceptors, predominantly of cones, and at the base of the primary cilium of fibroblasts. Interaction studies also showed that CEP78 binds to FAM161A, another ciliary protein associated with retinal degeneration. Finally, analysis of skin fibroblasts derived from affected individuals revealed abnormal ciliary morphology, as compared to that of control cells. Altogether, our data strongly suggest that mutations in CEP78 cause a previously undescribed clinical entity of a ciliary nature characterized by blindness and deafness but clearly distinct from Usher syndrome, a condition for which visual impairment is due to retinitis pigmentosa. PMID:27588451

  6. Rhodopsin coexpression in UV photoreceptors of Aedes aegypti and Anopheles gambiae mosquitoes

    OpenAIRE

    Hu, Xiaobang; Leming, Matthew T; Whaley, Michelle A.; O'Tousa, Joseph E.

    2014-01-01

    Differential rhodopsin gene expression within specialized R7 photoreceptor cells divides the retinas of Aedes aegypti and Anopheles gambiae mosquitoes into distinct domains. The two species express the rhodopsin orthologs Aaop8 and Agop8, respectively, in a large subset of these R7 photoreceptors that function as ultraviolet receptors. We show here that a divergent subfamily of mosquito rhodopsins, Aaop10 and Agop10, is coexpressed in these R7 photoreceptors. The properties of the A. aegypti ...

  7. Alterations in Kainate Receptor and TRPM1 Localization in Bipolar Cells after Retinal Photoreceptor Degeneration

    OpenAIRE

    Gayet-Primo, Jacqueline; Puthussery, Theresa

    2015-01-01

    Photoreceptor degeneration differentially impacts glutamatergic signaling in downstream On and Off bipolar cells. In rodent models, photoreceptor degeneration leads to loss of glutamatergic signaling in On bipolar cells, whereas Off bipolar cells appear to retain glutamate sensitivity, even after extensive photoreceptor loss. The localization and identity of the receptors that mediate these residual glutamate responses in Off bipolar cells have not been determined. Recent studies show that ma...

  8. Alterations in kainate receptor and TRPM1 localization in bipolar cells after retinal photoreceptor degeneration

    OpenAIRE

    Jacqueline eGayet-Primo; Theresa ePuthussery

    2015-01-01

    Photoreceptor degeneration differentially impacts glutamatergic signaling in downstream On and Off bipolar cells. In rodent models, photoreceptor degeneration leads to loss of glutamatergic signaling in On bipolar cells, whereas Off bipolar cells appear to retain glutamate sensitivity, even after extensive photoreceptor loss. The localization and identity of the receptors that mediate these residual glutamate responses in Off bipolar cells have not been determined. Recent studies show that ma...

  9. Use of Hydrogen as a Novel Therapeutic Strategy Against Photoreceptor Degeneration in Retinitis Pigmentosa Patients

    OpenAIRE

    Tao, Ye; Geng, Lei; Wang, Liqiang; Xu, Weiwei; Qin, Limin; Peng, Guanghua; Huang, Yi Fei; Yang, Ji xue

    2016-01-01

    Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterized by progressive photoreceptor apoptosis. Reactive oxygen species (ROS) have been recognized as critical initiators of the photoreceptor apoptosis in RP. Photoreceptor survival in RP mutants will not only require the inhibition of effectors of apoptotic machinery, but also the elimination of the initiating upstream signals, such as ROS. These cytotoxic ROS should be neutralized by the antioxidant d...

  10. Micromagnetic modelling of ferromagnetic cones

    OpenAIRE

    Boardman, Richard P.; Fangohr, Hans; Fairman, Matthew J.; Zimmermann, Jürgen; COX Simon J.; Zhukov, Alexander A.; de Groot, Peter A. J.

    2007-01-01

    Using micromagnetic modelling, we calculate numerically the magnetization reversal of soft permalloy cones of height and diameter View the MathML source. By varying the cone height and the base diameter in steps of 10 and 5 nm, respectively, we map the remanent states systematically. We observe reversal mechanisms with remanent configurations ranging from single domains at small diameters, through buckle states and complex C-states through to vortex states at larger diameters and heights. We ...

  11. Thromboelastography in Selected Avian Species.

    Science.gov (United States)

    Strindberg, Sophie; Nielsen, Tenna W; Ribeiro, Ângela M; Wiinberg, Bo; Kristensen, Annemarie T; Bertelsen, Mads F

    2015-12-01

    Currently available assay methods and reagents are not optimized for evaluating avian hemostasis; therefore, assessing avian coagulopathies is challenging. Recently, thromboelastography (TEG), which measures the viscoelastic properties of blood, has been used clinically in mammalian species to diagnose and characterize hemostatic disorders. To evaluate TEG in healthy individuals of 6 avian species, we modified existing mammalian TEG protocols to allow analysis of citrated, avian whole-blood samples collected from scarlet ibis (Eudocimus ruber) (n = 13), American flamingos ( Phoenicopterus ruber ) (n = 13), helmeted Guinea fowl ( Numida meleagris ) (n = 12), Amazon parrots (Amazona species) (n = 9), Humboldt penguins ( Spheniscus humboldti ) (n = 6), and domestic chickens (n = 16). Activated partial thromboplastin time, prothrombin time, and fibrinogen were measured as a means of comparison. Regardless of the mode of activation, clot formation in the species studied was markedly delayed compared with mammals. Because of prolonged reaction time (14.7-52.7 minutes) with kaolin and diluted tissue factor, undiluted human tissue factor was used in all avian samples because it provided the shortest reaction time. Species differed significantly in reaction time (P = .007), clotting rate (P < .001), rate of clot formation (α angle; P < .001), and maximum amplitude (P < .001) values, indicating that species-specific reference intervals are necessary. Based on these results, TEG with specific reference intervals could prove useful in evaluating avian hemostatic disorders. PMID:26771317

  12. Light cone approach

    International Nuclear Information System (INIS)

    One of the most challenging problems in theoretical high energy physics is to compute the bound state structure of the proton and other hadrons from quantum chromodynamics (QCD), the field theory of quarks and gluons. The goal is not only to calculate the spectrum of hadrons masses from first principles, but also to derive the momentum and spin distributions of the quarks and gluons which control high energy hadron interactions. One approach to these difficult calculations is to simulate QCD on an artificial lattice. Recently, several new methods based on ''light-cone'' quantization have been proposed as alternatives to lattice theory for solving non-perturbative problems in QCD and other field theories. The basic idea is a generalization of Heisenberg's pioneer matrix formulation of quantum mechanics: if one could numerically diagonalize the matrix of the Hamiltonian representing the underlying QCD interaction, then the resulting eigenvalues would give the hadron spectrum, while the corresponding eigenstates would describe each hadron in terms of its quark and gluon degrees of freedom

  13. Genetic interaction of centrosomin and bazooka in apical domain regulation in Drosophila photoreceptor.

    Directory of Open Access Journals (Sweden)

    Geng Chen

    Full Text Available BACKGROUND: Cell polarity genes including Crumbs (Crb and Par complexes are essential for controlling photoreceptor morphogenesis. Among the Crb and Par complexes, Bazooka (Baz, Par-3 homolog acts as a nodal component for other cell polarity proteins. Therefore, finding other genes interacting with Baz will help us to understand the cell polarity genes' role in photoreceptor morphogenesis. METHODOLOGY/PRINCIPAL FINDINGS: Here, we have found a genetic interaction between baz and centrosomin (cnn. Cnn is a core protein for centrosome which is a major microtubule-organizing center. We analyzed the effect of the cnn mutation on developing eyes to determine its role in photoreceptor morphogenesis. We found that Cnn is dispensable for retinal differentiation in eye imaginal discs during the larval stage. However, photoreceptors deficient in Cnn display dramatic morphogenesis defects including the mislocalization of Crumbs (Crb and Bazooka (Baz during mid-stage pupal eye development, suggesting that Cnn is specifically required for photoreceptor morphogenesis during pupal eye development. This role of Cnn in apical domain modulation was further supported by Cnn's gain-of-function phenotype. Cnn overexpression in photoreceptors caused the expansion of the apical Crb membrane domain, Baz and adherens junctions (AJs. CONCLUSIONS/SIGNIFICANCE: These results strongly suggest that the interaction of Baz and Cnn is essential for apical domain and AJ modulation during photoreceptor morphogenesis, but not for the initial photoreceptor differentiation in the Drosophila photoreceptor.

  14. Blue cone monochromacy: visual function and efficacy outcome measures for clinical trials.

    Directory of Open Access Journals (Sweden)

    Xunda Luo

    Full Text Available Blue Cone Monochromacy (BCM is an X-linked retinopathy caused by mutations in the OPN1LW / OPN1MW gene cluster, encoding long (L- and middle (M-wavelength sensitive cone opsins. Recent evidence shows sufficient structural integrity of cone photoreceptors in BCM to warrant consideration of a gene therapy approach to the disease. In the present study, the vision in BCM is examined, specifically seeking clinically-feasible outcomes for a future clinical trial.BCM patients (n = 25, ages 5-72 were studied with kinetic and static chromatic perimetry, full-field sensitivity testing, and eye movement recordings. Vision at the fovea and parafovea was probed with chromatic microperimetry.Kinetic fields with a Goldmann size V target were generally full. Short-wavelength (S- sensitive cone function was normal or near normal in most patients. Light-adapted perimetry results on conventional background lights were abnormally reduced; 600-nm stimuli were seen by rods whereas white stimuli were seen by both rods and S-cones. Under dark-adapted conditions, 500-nm stimuli were seen by rods in both BCM and normals. Spectral sensitivity functions in the superior retina showed retained rod and S-cone functions in BCM under dark-adapted and light-adapted conditions. In the fovea, normal subjects showed L/M-cone mediation using a 650-nm stimulus under dark-adapted conditions, whereas BCM patients had reduced sensitivity driven by rod vision. Full-field red stimuli on bright blue backgrounds were seen by L/M-cones in normal subjects whereas BCM patients had abnormally reduced and rod-mediated sensitivities. Fixation location could vary from fovea to parafovea. Chromatic microperimetry demonstrated a large loss of sensitivity to red stimuli presented on a cyan adapting background at the anatomical fovea and surrounding parafovea.BCM rods continue to signal vision under conditions normally associated with daylight vision. Localized and retina-wide outcome measures were

  15. Bicarbonate and Ca(2+) Sensing Modulators Activate Photoreceptor ROS-GC1 Synergistically.

    Science.gov (United States)

    Duda, Teresa; Pertzev, Alexandre; Makino, Clint L; Sharma, Rameshwar K

    2016-01-01

    Photoreceptor ROS-GC1, a prototype subfamily member of the membrane guanylate cyclase family, is a central component of phototransduction. It is a single transmembrane-spanning protein, composed of modular blocks. In rods, guanylate cyclase activating proteins (GCAPs) 1 and 2 bind to its juxtamembrane domain (JMD) and the C-terminal extension, respectively, to accelerate cyclic GMP synthesis when Ca(2+) levels are low. In cones, the additional expression of the Ca(2+)-dependent guanylate cyclase activating protein (CD-GCAP) S100B which binds to its C-terminal extension, supports acceleration of cyclic GMP synthesis at high Ca(2+) levels. Independent of Ca(2+), ROS-GC1 activity is also stimulated directly by bicarbonate binding to the core catalytic domain (CCD). Several enticing molecular features of this transduction system are revealed in the present study. In combination, bicarbonate and Ca(2+)-dependent modulators raised maximal ROS-GC activity to levels that exceeded the sum of their individual effects. The F(514)S mutation in ROS-GC1 that causes blindness in type 1 Leber's congenital amaurosis (LCA) severely reduced basal ROS-GC1 activity. GCAP2 and S100B Ca(2+) signaling modes remained functional, while the GCAP1-modulated mode was diminished. Bicarbonate nearly restored basal activity as well as GCAP2- and S100B-stimulated activities of the F(514)S mutant to normal levels but could not resurrect GCAP1 stimulation. We conclude that GCAP1 and GCAP2 forge distinct pathways through domain-specific modules of ROS-GC1 whereas the S100B and GCAP2 pathways may overlap. The synergistic interlinking of bicarbonate to GCAPs- and S100B-modulated pathways intensifies and tunes the dependence of cyclic GMP synthesis on intracellular Ca(2+). Our study challenges the recently proposed GCAP1 and GCAP2 "overlapping" phototransduction model (Peshenko et al., 2015b). PMID:26858600

  16. A "melanopic" spectral efficiency function predicts the sensitivity of melanopsin photoreceptors to polychromatic lights.

    Science.gov (United States)

    Enezi, Jazi al; Revell, Victoria; Brown, Timothy; Wynne, Jonathan; Schlangen, Luc; Lucas, Robert

    2011-08-01

    Photoreception in the mammalian retina is not restricted to rods and cones but extends to a small number of intrinsically photosensitive retinal ganglion cells expressing the photopigment melanopsin. These mRGCs are especially important contributors to circadian entrainment, the pupil light reflex, and other so-called nonimage-forming (NIF) responses. The spectral sensitivity of melanopsin phototransduction has been addressed in several species by comparing responses to a range of monochromatic stimuli. The resultant action spectra match the predicted profile of an opsin:vitamin A-based photopigment (nomogram) with a peak sensitivity (λ(max)) around 480 nm. It would be most useful to be able to use this spectral sensitivity function to predict melanopsin's sensitivity to broad-spectrum, including "white," lights. However, evidence that melanopsin is a bistable pigment with an intrinsic light-dependent bleach recovery mechanism raises the possibility of a more complex relationship between spectral quality and photoreceptor response. Here, we set out to empirically determine whether simply weighting optical power at each wavelength according to the 480-nm nomogram and integrating across the spectrum could predict melanopsin sensitivity to a variety of polychromatic stimuli. We show that pupillomotor and circadian responses of mice relying solely on melanopsin for their photosensitivity (rd/rd cl) can indeed be accurately predicted using this methodology. Our data therefore suggest that the 480-nm nomogram may be employed as the basis for a new photometric measure of light intensity (which we term "melanopic") relevant for melanopsin photoreception. They further show that measuring light in these terms predicts the melanopsin response to light of divergent spectral composition much more reliably than other methods for quantifying irradiance or illuminance currently in widespread use. PMID:21775290

  17. Role of kinesin heavy chain in Crumbs localization along the rhabdomere elongation in Drosophila photoreceptor.

    Directory of Open Access Journals (Sweden)

    Garrett P League

    Full Text Available BACKGROUND: Crumbs (Crb, a cell polarity gene, has been shown to provide a positional cue for the extension of the apical membrane domain, adherens junction (AJ, and rhabdomere along the growing proximal-distal axis during Drosophila photoreceptor morphogenesis. In developing Drosophila photoreceptors, a stabilized microtubule structure was discovered and its presence was linked to polarity protein localization. It was therefore hypothesized that the microtubules may provide trafficking routes for the polarity proteins during photoreceptor morphogenesis. This study has examined whether Kinesin heavy chain (Khc, a subunit of the microtubule-based motor Kinesin-1, is essential in polarity protein localization in developing photoreceptors. METHODOLOGY/PRINCIPAL FINDINGS: Because a genetic interaction was found between crb and khc, Crb localization was examined in the developing photoreceptors of khc mutants. khc was dispensable during early eye differentiation and development. However, khc mutant photoreceptors showed a range of abnormalities in the apical membrane domain depending on the position along the proximal-distal axis in pupal photoreceptors. The khc mutant showed a progressive mislocalization in the apical domain along the distal-proximal axis during rhabdomere elongation. The khc mutation also led to a similar progressive defect in the stabilized microtubule structures, strongly suggesting that Khc is essential for microtubule structure and Crb localization during distal to proximal rhabdomere elongation in pupal morphogenesis. This role of Khc in apical domain control was further supported by khc's gain-of-function phenotype. Khc overexpression in photoreceptors caused disruption of the apical membrane domain and the stabilized microtubules in the developing photoreceptors. CONCLUSIONS/SIGNIFICANCE: In summary, we examined the role of khc in the regulation of the apical Crb domain in developing photoreceptors. Since the rhabdomeres in

  18. Avian mycoplasmosis update

    Directory of Open Access Journals (Sweden)

    ER Nascimento

    2005-03-01

    Full Text Available Avian mycoplasmas occur in a variety of bird species. The most important mycoplasmas for chickens and turkeys are Mycoplasma gallisepticum (MG, M. synoviae (MS, and M. meleagridis. Besides, M. iowe (MI is an emerging pathogen in turkeys, but of little concern for chickens. Mycoplasmas are bacteria that lack cell wall and belong to the class Mollicutes. Although they have been considered extracellular agents, scientists admit nowadays that some of them are obligatory intracellular microorganisms, whereas all other mycoplasmas are considered facultative intracellular organisms. Their pathogenic mechanism for disease include adherence to host target cells, mediation of apoptosis, innocent bystander damage to host cell due to intimate membrane contact, molecular (antigen mimicry that may lead to tolerance, and mitotic effect for B and/or T lymphocytes, which could lead to suppressed T-cell function and/or production of cytotoxic T cell, besides mycoplasma by-products, such as hydrogen peroxide and superoxide radicals. Moreover, mycoplasma ability to stimulate macrophages, monocytes, T-helper cells and NK cells, results in the production of substances, such as tumor necrosing factor (TNF-alpha, interleukin (IL-1, 2, 6 and interferon (a, b, g. The major clinical signs seen in avian mycoplasmosis are coughing, sneezing, snicks, respiratory rales, ocular and nasal discharge, decreased feed intake and egg production, increased mortality, poor hatchability, and, primarily in turkeys, swelling of the infraorbital sinus(es. Nevertheless, chronic and unapparent infections are most common and more threatening. Mycoplasmas are transmitted horizontally, from bird to bird, and vertically, from dam to offspring through the eggs. Losses attributed to mycoplasmosis, mainly MG and MS infections, result from decreased egg production and egg quality, poor hatchability (high rate of embryonic mortality and culling of day-old birds, poor feed efficiency, increase in

  19. Markov Chain Estimation of Avian Seasonal Fecundity

    Science.gov (United States)

    To explore the consequences of modeling decisions on inference about avian seasonal fecundity we generalize previous Markov chain (MC) models of avian nest success to formulate two different MC models of avian seasonal fecundity that represent two different ways to model renestin...

  20. An overview on avian influenza

    Directory of Open Access Journals (Sweden)

    Nelson Rodrigo da Silva Martins

    2012-06-01

    Full Text Available Avian influenza (AI is considered an exotic disease in the Brazilian poultry industry, according to the National Avian Health Program (PNSA, with permanent monitoring of domestic, exotic and native avian species. Brazil presents privileged environmental conditions of reduced risk. In addition, all commercial poultry and conservation holdings are registered in state or national inventories and geographically located (GPS for health control. Poultry health standards are adopted for the conformity to the international market, mostly for the intensified poultry destined for exportation, but also for companion exotic and native conservation facilities. Guidelines for monitoring and the diagnosis of AI are published by the PNSA and follow the standards proposed by the international health code (World Organization for Animal Health, Organization International des Epizooties - OIE and insure the free of status for avian influenza virus (AIV of LPAIV-low pathogenicity AIV and HPAIV-high pathogenicity AIV. In addition, the infections by mesogenic and velogenic Newcastle disease virus, Mycoplasma gallisepticum, M. synoviae and M. meleagridis, Salmonella enteric subspecies enterica serovar Gallinarum biovars Gallinarum and Pullorum are eradicated from reproduction. Controlled infections by S.enterica subspecies enterica serovars Enteritidis and Typhimurium are monitored for breeders. The vaccination of chickens in ovo or at hatch against Marek's disease is mandatory. Broiler production is an indoor activity, confinement which insures biosecurity, with safe distances from the potential AIV reservoir avian species. Worldwide HPAIV H5N1 notifications to the OIE, in March 2011, included 51 countries.

  1. Cobalamin's (Vitamin B12) Surprising Function as a Photoreceptor.

    Science.gov (United States)

    Cheng, Zhuo; Yamamoto, Haruki; Bauer, Carl E

    2016-08-01

    Cobalamin (Vitamin B12) is an adenosyl- or methyl-donating cofactor for many enzymes, yet many proteins with unknown or nonenzymatic function also contain B12-binding domains. Recent studies show that light excitation energy can promote covalent linkage of B12 to transcription factors with this linkage, affecting gene expression. Thus, B12 now has a newly described regulatory function. Here, our bioinformatics analysis reveals other transcription factors, photoreceptors, kinases, and oxygen sensors that harbor a B12-binding domain that could also regulate activity in response to light absorption. PMID:27217104

  2. Avian infectious laryngotracheitis.

    Science.gov (United States)

    Bagust, T J; Jones, R C; Guy, J S

    2000-08-01

    Avian infectious laryngotracheitis (ILT) herpesvirus continues to cause sporadic cases of respiratory disease in chickens world-wide. Sources of transmission of ILT infection are three-fold, namely: chickens with acute upper respiratory tract disease, latently infected 'carrier' fowls which excrete infectious laryngotracheitis virus (ILTV) when stressed, and all fomites (inanimate articles as well as the personnel in contact with infected chickens). Infectious laryngotracheitis virus infectivity can persist for weeks to months in tracheal mucus or carcasses. Rigorous site biosecurity is therefore critical in ILT disease control. Furthermore, while current (modified live) ILT vaccines can offer good protection, the strains of ILTV used in vaccines can also produce latent infections, as well as ILT disease following bird-to-bird spread. The regional nature of reservoirs of ILTV-infected flocks will tend to interact unfavourably with widely varying ILT control practices in the poultry industry, so as to periodically result in sporadic and unexpected outbreaks of ILT in intensive poultry industry populations. Precautions for trade-related movements of chickens of all ages must therefore include an accurate knowledge of the ILT infection status, both of the donor and recipient flocks. PMID:10935275

  3. Alterations in kainate receptor and TRPM1 localization in bipolar cells after retinal photoreceptor degeneration

    Directory of Open Access Journals (Sweden)

    Jacqueline eGayet-Primo

    2015-12-01

    Full Text Available Photoreceptor degeneration differentially impacts glutamatergic signaling in downstream On and Off bipolar cells. In rodent models, photoreceptor degeneration leads to loss of glutamatergic signaling in On bipolar cells, whereas Off bipolar cells appear to retain glutamate sensitivity, even after extensive photoreceptor loss. The localization and identity of the receptors that mediate these residual glutamate responses in Off bipolar cells have not been determined. Recent studies show that macaque and mouse Off bipolar cells receive glutamatergic input primarily through kainate-type glutamate receptors. Here, we studied the impact of photoreceptor degeneration on glutamate receptor associated proteins in Off and On bipolar cells. We show that the kainate receptor subunit, GluK1, persists in remodeled Off bipolar cell dendrites of the rd10 mouse retina. However, the pattern of expression is altered and the intensity of staining is reduced compared to wild-type retina. The kainate receptor auxiliary subunit, Neto1, also remains in Off bipolar cell dendrites after complete photoreceptor degeneration. Similar preservation of kainate receptor subunits was evident in human retina in which photoreceptors had degenerated due to serous retinal detachment. In contrast, photoreceptor degeneration leads to loss of synaptic expression of TRPM1 in mouse and human On bipolar cells, but strong somatic expression remains. These findings demonstrate that Off bipolar cells retain dendritic glutamate receptors during retinal degeneration and could thus serve as a conduit for signal transmission from transplanted or optogenetically-restored photoreceptors.

  4. Evidence for dynamic network regulation of Drosophila photoreceptor function from mutants lacking the neurotransmitter histamine

    Directory of Open Access Journals (Sweden)

    An eDau

    2016-03-01

    Full Text Available Synaptic feedback from interneurons to photoreceptors can help to optimize visual information flow by balancing its allocation on retinal pathways under changing light conditions. But little is known about how this critical network operation is regulated dynamically. Here, we investigate this question by comparing signaling properties and performance of wild-type Drosophila R1-R6 photoreceptors to those of the hdcJK910 mutant, which lacks the neurotransmitter histamine and therefore cannot transmit information to interneurons. Recordings show that hdcJK910 photoreceptors sample similar amounts of information from naturalistic stimulation to wild-type photoreceptors, but this information is packaged in smaller responses, especially under bright illumination. Analyses reveal how these altered dynamics primarily resulted from network overload that affected hdcJK910 photoreceptors in two ways. First, the missing inhibitory histamine input to interneurons almost certainly depolarized them irrevocably, which in turn increased their excitatory feedback to hdcJK910 R1-R6s. This tonic excitation depolarized the photoreceptors to artificially high potentials, reducing their operational range. Second, rescuing histamine input to interneurons in hdcJK910 mutant also restored their normal phasic feedback modulation to R1-R6s, causing photoreceptor output to accentuate dynamic intensity differences at bright illumination, similar to the wild-type. These results provide mechanistic explanations of how synaptic feedback connections optimize information packaging in photoreceptor output and novel insight into the operation and design of dynamic network regulation of sensory neurons.

  5. Evidence for Dynamic Network Regulation of Drosophila Photoreceptor Function from Mutants Lacking the Neurotransmitter Histamine.

    Science.gov (United States)

    Dau, An; Friederich, Uwe; Dongre, Sidhartha; Li, Xiaofeng; Bollepalli, Murali K; Hardie, Roger C; Juusola, Mikko

    2016-01-01

    Synaptic feedback from interneurons to photoreceptors can help to optimize visual information flow by balancing its allocation on retinal pathways under changing light conditions. But little is known about how this critical network operation is regulated dynamically. Here, we investigate this question by comparing signaling properties and performance of wild-type Drosophila R1-R6 photoreceptors to those of the hdc (JK910) mutant, which lacks the neurotransmitter histamine and therefore cannot transmit information to interneurons. Recordings show that hdc (JK910) photoreceptors sample similar amounts of information from naturalistic stimulation to wild-type photoreceptors, but this information is packaged in smaller responses, especially under bright illumination. Analyses reveal how these altered dynamics primarily resulted from network overload that affected hdc (JK910) photoreceptors in two ways. First, the missing inhibitory histamine input to interneurons almost certainly depolarized them irrevocably, which in turn increased their excitatory feedback to hdc (JK910) R1-R6s. This tonic excitation depolarized the photoreceptors to artificially high potentials, reducing their operational range. Second, rescuing histamine input to interneurons in hdc (JK910) mutant also restored their normal phasic feedback modulation to R1-R6s, causing photoreceptor output to accentuate dynamic intensity differences at bright illumination, similar to the wild-type. These results provide mechanistic explanations of how synaptic feedback connections optimize information packaging in photoreceptor output and novel insight into the operation and design of dynamic network regulation of sensory neurons. PMID:27047343

  6. Photoreceptor processing speed and input resistance changes during light adaptation correlate with spectral class in the bumblebee, Bombus impatiens.

    Directory of Open Access Journals (Sweden)

    Peter Skorupski

    Full Text Available Colour vision depends on comparison of signals from photoreceptors with different spectral sensitivities. However, response properties of photoreceptor cells may differ in ways other than spectral tuning. In insects, for example, broadband photoreceptors, with a major sensitivity peak in the green region of the spectrum (>500 nm, drive fast visual processes, which are largely blind to chromatic signals from more narrowly-tuned photoreceptors with peak sensitivities in the blue and UV regions of the spectrum. In addition, electrophysiological properties of the photoreceptor membrane may result in differences in response dynamics of photoreceptors of similar spectral class between species, and different spectral classes within a species. We used intracellular electrophysiological techniques to investigate response dynamics of the three spectral classes of photoreceptor underlying trichromatic colour vision in the bumblebee, Bombus impatiens, and we compare these with previously published data from a related species, Bombus terrestris. In both species, we found significantly faster responses in green, compared with blue- or UV-sensitive photoreceptors, although all 3 photoreceptor types are slower in B. impatiens than in B. terrestris. Integration times for light-adapted B. impatiens photoreceptors (estimated from impulse response half-width were 11.3 ± 1.6 ms for green photoreceptors compared with 18.6 ± 4.4 ms and 15.6 ± 4.4 for blue and UV, respectively. We also measured photoreceptor input resistance in dark- and light-adapted conditions. All photoreceptors showed a decrease in input resistance during light adaptation, but this decrease was considerably larger (declining to about 22% of the dark value in green photoreceptors, compared to blue and UV (41% and 49%, respectively. Our results suggest that the conductances associated with light adaptation are largest in green photoreceptors, contributing to their greater temporal processing speed

  7. Photoreceptor precursors derived from three-dimensional embryonic stem cell cultures integrate and mature within adult degenerate retina

    OpenAIRE

    Gonzalez-Cordero, Anai; West, Emma L.; Pearson, Rachael A.; Duran, Yanai; Carvalho, Livia S.; Chu, Colin J.; Naeem, Arifa; Blackford, Samuel J. I.; Georgiadis, Anastasios; Lakowski, Jorn; Hubank, Mike; Smith, Alexander J.; Bainbridge, James W. B.; Jane C Sowden; Ali, Robin R.

    2013-01-01

    Irreversible blindness caused by loss of photoreceptors may be amenable to cell therapy. We previously demonstrated retinal repair 1 and restoration of vision through transplantation of photoreceptor precursors obtained from post-natal retinas into visually impaired adult mice 2,3 . Considerable progress has been made in differentiating embryonic stem cells (ESCs) in vitro toward photoreceptor lineages 4-6 . However, the capability of ESC-derived photoreceptors to integrate after transplantat...

  8. Micromagnetic modelling of ferromagnetic cones

    International Nuclear Information System (INIS)

    Using micromagnetic modelling, we calculate numerically the magnetization reversal of soft permalloy cones of height and diameter =<100nm. By varying the cone height and the base diameter in steps of 10 and 5nm, respectively, we map the remanent states systematically. We observe reversal mechanisms with remanent configurations ranging from single domains at small diameters, through buckle states and complex C-states through to vortex states at larger diameters and heights. We present a phase diagram of the remanent states of magnetization as a function of diameter and height. For the largest cones investigated, we find magnetization configurations in the reversal process which consist of two superimposed vortices with cores pointing in orthogonal directions

  9. Shatter cones: (Mis)understood?

    Science.gov (United States)

    Osinski, Gordon R.; Ferrière, Ludovic

    2016-01-01

    Meteorite impact craters are one of the most common geological features in the solar system. An impact event is a near-instantaneous process that releases a huge amount of energy over a very small region on a planetary surface. This results in characteristic changes in the target rocks, from vaporization and melting to solid-state effects, such as fracturing and shock metamorphism. Shatter cones are distinctive striated conical fractures that are considered unequivocal evidence of impact events. They are one of the most used and trusted shock-metamorphic effects for the recognition of meteorite impact structures. Despite this, there is still considerable debate regarding their formation. We show that shatter cones are present in several stratigraphic settings within and around impact structures. Together with the occurrence of complete and “double” cones, our observations are most consistent with shatter cone formation due to tensional stresses generated by scattering of the shock wave due to heterogeneities in the rock. On the basis of field mapping, we derive the relationship Dsc = 0.4 Da, where Dsc is the maximum spatial extent of in situ shatter cones, and Da is the apparent crater diameter. This provides an important, new, more accurate method to estimate the apparent diameter of eroded complex craters on Earth. We have reestimated the diameter of eight well-known impact craters as part of this study. Finally, we suggest that shatter cones may reduce the strength of the target, thus aiding crater collapse, and that their distribution in central uplifts also records the obliquity of impact. PMID:27532050

  10. Avian influenza virus in pregnancy.

    Science.gov (United States)

    Liu, Shelan; Sha, Jianping; Yu, Zhao; Hu, Yan; Chan, Ta-Chien; Wang, Xiaoxiao; Pan, Hao; Cheng, Wei; Mao, Shenghua; Zhang, Run Ju; Chen, Enfu

    2016-07-01

    The unprecedented epizootic of avian influenza viruses, such as H5N1, H5N6, H7N1 and H10N8, has continued to cause disease in humans in recent years. In 2013, another novel influenza A (H7N9) virus emerged in China, and 30% of those patients died. Pregnant women are particularly susceptible to avian influenza and are more likely to develop severe complications and to die, especially when infection occurs in the middle and late trimesters. Viremia is believed to occur infrequently, and thus vertical transmission induced by avian influenza appears to be rare. However, avian influenza increases the risk of adverse pregnancy outcomes, including spontaneous abortion, preterm birth and fatal distress. This review summarises 39 cases of pregnant women and their fetuses from different countries dating back to 1997, including 11, 15 and 13 infections with H7N9, H5N1 and the 2009 pandemic influenza (H1N1), respectively. We analysed the epidemic features, following the geographical, population and pregnancy trimester distributions; underlying diseases; exposure history; medical timelines; human-to-human transmission; pathogenicity and vertical transmission; antivirus treatments; maternal severity and mortality and pregnancy outcome. The common experiences reported in different countries and areas suggest that early identification and treatment are imperative. In the future, vigilant virologic and epidemiologic surveillance systems should be developed to monitor avian influenza viruses during pregnancy. Furthermore, extensive study on the immune mechanisms should be conducted, as this will guide safe, rational immunomodulatory treatment among this high-risk population. Most importantly, we should develop a universal avian influenza virus vaccine to prevent outbreaks of the different subtypes. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27187752

  11. The two-step development of a duplex retina involves distinct events of cone and rod neurogenesis and differentiation.

    Science.gov (United States)

    Valen, Ragnhild; Eilertsen, Mariann; Edvardsen, Rolf Brudvik; Furmanek, Tomasz; Rønnestad, Ivar; van der Meeren, Terje; Karlsen, Ørjan; Nilsen, Tom Ole; Helvik, Jon Vidar

    2016-08-15

    Unlike in mammals, persistent postembryonic retinal growth is a characteristic feature of fish, which includes major remodeling events that affect all cell types including photoreceptors. Consequently, visual capabilities change during development, where retinal sensitivity to different wavelengths of light (photopic vision), -and to limited photons (scotopic vision) are central capabilities for survival. Differently from well-established model fish, Atlantic cod has a prolonged larval stage where only cone photoreceptors are present. Rods do not appear until juvenile transition (metamorphosis), a hallmark of indirect developing species. Previously we showed that whole gene families of lws (red-sensitive) and sws1 (UV-sensitive) opsins have been lost in cod, while rh2a (green-sensitive) and sws2 (blue-sensitive) genes have tandem duplicated. Here, we provide a comprehensive characterization of a two-step developing duplex retina in Atlantic cod. The study focuses on cone subtype dynamics and delayed rod neurogenesis and differentiation in all cod life stages. Using transcriptomic and histological approaches we show that different opsins disappear in a topographic manner during development where central to peripheral retina is a key axis of expressional change. Early cone differentiation was initiated in dorso-temporal retina different from previously described in fish. Rods first appeared during initiation of metamorphosis and expression of the nuclear receptor transcription factor nr2e3-1, suggest involvement in rod specification. The indirect developmental strategy thus allows for separate studies of cones and rods development, which in nature correlates with visual changes linked to habitat shifts. The clustering of key retinal genes according to life stage, suggests that Atlantic cod with its sequenced genome may be an important resource for identification of underlying factors required for development and function of photopic and scotopic vision. PMID:27374844

  12. Avian Influenza infection in Human

    OpenAIRE

    Mohan M; Trevor Francis Fernandez and Feroz Mohammed.M.S.

    2008-01-01

    Outbreaks caused by the H5N1 strain are presently of the greatest concern for human health. In assessing risks to human health, it is important to know exactly which avian virus strains are causing the outbreaks in birds.All available evidence points to an increased risk of transmission to humans when outbreaks of highly pathogenic avian H5N1 influenza are widespread in poultry. There is mounting evidence that this strain has a unique capacity to jump the species barrier and cause severe dise...

  13. Focal damage to macaque photoreceptors produces persistent visual loss.

    Science.gov (United States)

    Strazzeri, Jennifer M; Hunter, Jennifer J; Masella, Benjamin D; Yin, Lu; Fischer, William S; DiLoreto, David A; Libby, Richard T; Williams, David R; Merigan, William H

    2014-02-01

    Insertion of light-gated channels into inner retina neurons restores neural light responses, light evoked potentials, visual optomotor responses and visually-guided maze behavior in mice blinded by retinal degeneration. This method of vision restoration bypasses damaged outer retina, providing stimulation directly to retinal ganglion cells in inner retina. The approach is similar to that of electronic visual protheses, but may offer some advantages, such as avoidance of complex surgery and direct targeting of many thousands of neurons. However, the promise of this technique for restoring human vision remains uncertain because rodent animal models, in which it has been largely developed, are not ideal for evaluating visual perception. On the other hand, psychophysical vision studies in macaque can be used to evaluate different approaches to vision restoration in humans. Furthermore, it has not been possible to test vision restoration in macaques, the optimal model for human-like vision, because there has been no macaque model of outer retina degeneration. In this study, we describe development of a macaque model of photoreceptor degeneration that can in future studies be used to test restoration of perception by visual prostheses. Our results show that perceptual deficits caused by focal light damage are restricted to locations at which photoreceptors are damaged, that optical coherence tomography (OCT) can be used to track such lesions, and that adaptive optics retinal imaging, which we recently used for in vivo recording of ganglion cell function, can be used in future studies to examine these lesions. PMID:24316158

  14. Spectral Consequences of Photoreceptor Sampling in the Rhesus Retina

    Science.gov (United States)

    Yellott, John I.

    1983-07-01

    Optical transforms were used to compute the power spectra of rhesus cones treated as arrays of image sampling points. Spectra were obtained for the central fovea, parafovea, periphery, and far periphery. All were consistent with a novel spatial sampling principle that introduces minimal noise for spatial frequencies below the Nyquist limits implied by local receptor densities, while frequencies above the nominal Nyquist limits are not converted into conspicuous moire patterns, but instead are scattered into broadband noise. This sampling scheme allows the visual system to escape aliasing distortion despite a large mismatch between retinal image bandwidth and the Nyquist limits implied by extrafoveal cone densities.

  15. Avian reproductive physiology

    Science.gov (United States)

    Gee, G.F.

    1995-01-01

    Knowledge of the many physiological factors associated with egg production , fertility, incubation, and brooding in nondomestic birds is limited. Science knows even less about reproduction in most of the 238 endangered or threatened birds. This discussion uses studies of nondomestic and, when necessary, domestic birds to describe physiological control of reproduction. Studies of the few nondomestic avian species show large variation in physiological control of reproduction. Aviculturists, in order to successfully propagate an endangered bird, must understand the bird's reproductive peculiarities. First, investigators can do studies with carefully chosen surrogate species, but eventually they need to confirm the results in the target endangered bird. Studies of reproduction in nondomestic birds increased in the last decade. Still, scientists need to do more comparative studies to understand the mechanisms that control reproduction in birds. New technologies are making it possible to study reproductive physiology of nondomestic species in less limiting ways. These technologies include telemetry to collect information without inducing stress on captives (Howey et al., 1987; Klugman, 1987), new tests for most of the humoral factors associated with reproduction, and the skill to collect small samples and manipulate birds without disrupting the physiological mechanisms (Bercovitz et al., 1985). Managers are using knowledge from these studies to improve propagation in zoological parks, private and public propagation facilities, and research institutions. Researchers need to study the control of ovulation, egg formation, and oviposition in the species of nondomestic birds that lay very few eggs in a season, hold eggs in the oviduct for longer intervals, or differ in other ways from the more thoroughly studied domestic birds. Other techniques that would enhance propagation for nondomestlc birds include tissue culture of cloned embryonic cells, cryopreservation of embryos

  16. Molecular characterization of Indonesia avian influenza virus

    Directory of Open Access Journals (Sweden)

    N.L.P.I. Dharmayanti

    2005-06-01

    Full Text Available Avian influenza outbreaks in poultry have been reported in Java island since August 2003. A total of 14 isolates of avian influenza virus has been isolated from October 2003 to October 2004. The viruses have been identified as HPAI H5N1 subtype. All of them were characterized further at genetic level and also for their pathogenicity. Phylogenetic analysis showed all of the avian influenza virus isolates were closely related to avian influenza virus from China (A/Duck/China/E319-2/03(H5N1. Molecular basis of pathogenicity in HA cleavage site indicated that the isolates of avian influenza virus have multiple basic amino acid (B-X-B-R indicating that all of the isolates representing virulent avian influenza virus (highly pathogenic avian influenza virus.

  17. On the dual of the mobile cone

    CERN Document Server

    Choi, Sung Rak

    2010-01-01

    We prove that the cone of mobile divisors and the cone of curves birationally movable in codimension $1$ are dual in the $(K+B)$-negative part for a klt pair $(X/Z,B)$. We also prove the structure theorem and the contraction theorem for the expanded cone of curves birationally movable in codimension $1$. The duality of the cones gives a partial answer to the problem posed by Sam Payne.

  18. Rod-cone interaction in flicker perimetry.

    OpenAIRE

    Alexander, K. R.; Fishman, G. A.

    1984-01-01

    We have assessed the influence of the rod system on cone flicker sensitivity during flicker perimetry. For temporal frequencies above 18 Hz extrafoveal cone-mediated flicker thresholds for a white test stimulus are as much as 1.5 log units lower when measured against a large background light that saturates the rods than when measured in darkness. Following a Ganzfeld bleach extrafoveal cone flicker thresholds are at their minimum once the cones have recovered their sensitivity, but then thres...

  19. Natural History of Cone Disease in the Murine Model of Leber Congenital Amaurosis Due to CEP290 Mutation: Determining the Timing and Expectation of Therapy

    Science.gov (United States)

    Boye, Shannon E.; Huang, Wei-Chieh; Roman, Alejandro J.; Sumaroka, Alexander; Boye, Sanford L.; Ryals, Renee C.; Olivares, Melani B.; Ruan, Qing; Tucker, Budd A.; Stone, Edwin M.; Swaroop, Anand; Cideciyan, Artur V.; Hauswirth, William W.; Jacobson, Samuel G.

    2014-01-01

    Background Mutations in the CEP290 (cilia-centrosomal protein 290 kDa) gene in Leber congenital amaurosis (LCA) cause early onset visual loss but retained cone photoreceptors in the fovea, which is the potential therapeutic target. A cone-only mouse model carrying a Cep290 gene mutation, rd16;Nrl−/−, was engineered to mimic the human disease. In the current study, we determined the natural history of retinal structure and function in this murine model to permit design of pre-clinical proof-of-concept studies and allow progress to be made toward human therapy. Analyses of retinal structure and visual function in CEP290-LCA patients were also performed for comparison with the results in the model. Methods Rd16;Nrl−/− mice were studied in the first 90 days of life with optical coherence tomography (OCT), electroretinography (ERG), retinal histopathology and immunocytochemistry. Structure and function data from a cohort of patients with CEP290-LCA (n = 15; ages 7–48) were compared with those of the model. Results CEP290-LCA patients retain a central island of photoreceptors with normal thickness at the fovea (despite severe visual loss); the extent of this island declined slowly with age. The rd16;Nrl−/− model also showed a relatively slow photoreceptor layer decline in thickness with ∼80% remaining at 3 months. The number of pseudorosettes also became reduced. By comparison to single mutant Nrl−/− mice, UV- and M-cone ERGs of rd16;Nrl−/− were at least 1 log unit reduced at 1 month of age and declined further over the 3 months of monitoring. Expression of GNAT2 and S-opsin also decreased with age. Conclusions The natural history of early loss of photoreceptor function with retained cone cell nuclei is common to both CEP290-LCA patients and the rd16;Nrl−/− murine model. Pre-clinical proof-of-concept studies for uniocular therapies would seem most appropriate to begin with intervention at P35–40 and re-study after one month by assaying

  20. Possible involvement of cone opsins in distinct photoresponses of intrinsically photosensitive dermal chromatophores in tilapia Oreochromis niloticus.

    Directory of Open Access Journals (Sweden)

    Shyh-Chi Chen

    Full Text Available Dermal specialized pigment cells (chromatophores are thought to be one type of extraretinal photoreceptors responsible for a wide variety of sensory tasks, including adjusting body coloration. Unlike the well-studied image-forming function in retinal photoreceptors, direct evidence characterizing the mechanism of chromatophore photoresponses is less understood, particularly at the molecular and cellular levels. In the present study, cone opsin expression was detected in tilapia caudal fin where photosensitive chromatophores exist. Single-cell RT-PCR revealed co-existence of different cone opsins within melanophores and erythrophores. By stimulating cells with six wavelengths ranging from 380 to 580 nm, we found melanophores and erythrophores showed distinct photoresponses. After exposed to light, regardless of wavelength presentation, melanophores dispersed and maintained cell shape in an expansion stage by shuttling pigment granules. Conversely, erythrophores aggregated or dispersed pigment granules when exposed to short- or middle/long-wavelength light, respectively. These results suggest that diverse molecular mechanisms and light-detecting strategies may be employed by different types of tilapia chromatophores, which are instrumental in pigment pattern formation.

  1. Hanford waste tank cone penetrometer

    International Nuclear Information System (INIS)

    A new tool is being developed to characterize tank waste at the Hanford Reservation. This tool, known as the cone penetrometer, is capable of obtaining chemical and physical properties in situ. For the past 50 years, this tool has been used extensively in soil applications and now has been modified for usage in Hanford Underground Storage tanks. These modifications include development of new ''waste'' data models as well as hardware design changes to accommodate the hazardous and radioactive environment of the tanks. The modified cone penetrometer is scheduled to be deployed at Hanford by Fall 1996. At Hanford, the cone penetrometer will be used as an instrumented pipe which measures chemical and physical properties as it pushes through tank waste. Physical data, such as tank waste stratification and mechanical properties, is obtained through three sensors measuring tip pressure, sleeve friction and pore pressure. Chemical data, such as chemical speciation, is measured using a Raman spectroscopy sensor. The sensor package contains other instrumentation as well, including a tip and side temperature sensor, tank bottom detection and an inclinometer. Once the cone penetrometer has reached the bottom of the tank, a moisture probe will be inserted into the pipe. This probe is used to measure waste moisture content, water level, waste surface moisture and tank temperature. This paper discusses the development of this new measurement system. Data from the cone penetrometer will aid in the selection of sampling tools, waste tank retrieval process, and addressing various tank safety issues. This paper will explore various waste models as well as the challenges associated with tank environment

  2. Influenza vaccines for avian species

    Science.gov (United States)

    Beginning in Southeast Asia, in 2003, a multi-national epizootic outbreak of H5N1 highly pathogenic avian influenza (HPAI) was identified in commercial poultry and wild bird species. This lineage, originally identified in Southern China in 1996 and then Hong Kong in 1997, caused severe morbidity an...

  3. Thromboelastography in Selected Avian Species

    DEFF Research Database (Denmark)

    Strindberg, Sophie; Nielsen, Tenna W; Ribeiro, Ângela M;

    2015-01-01

    . Regardless of the mode of activation, clot formation in the species studied was markedly delayed compared with mammals. Because of prolonged reaction time (14.7-52.7 minutes) with kaolin and diluted tissue factor, undiluted human tissue factor was used in all avian samples because it provided the shortest...

  4. OFFLU Network on Avian Influenza

    OpenAIRE

    Edwards, Steven

    2006-01-01

    OFFLU is the name of the network of avian influenza expertise inaugurated jointly in 2005 by the Food and Agriculture Organization of the United Nations and the World Organisation for Animal Health. Achievements and constraints to date and plans for the future are described.

  5. Avian Influenza: Our current understanding

    Science.gov (United States)

    Avian influenza virus (AIV) has become one of the most important diseases of the poultry industry around the world. The virus has a broad host range in birds and mammals, although the natural reservoir is considered to be in wild birds where it typically causes an asymptomatic to mild infection. T...

  6. Avian influenza virus RNA extraction

    Science.gov (United States)

    The efficient extraction and purification of viral RNA is critical for down-stream molecular applications whether it is the sensitive and specific detection of virus in clinical samples, virus gene cloning and expression, or quantification of avian influenza (AI) virus by molecular methods from expe...

  7. 11-cis-retinal reduces constitutive opsin phosphorylation and improves quantum catch in retinoid-deficient mouse rod photoreceptors.

    Science.gov (United States)

    Ablonczy, Zsolt; Crouch, Rosalie K; Goletz, Patrice W; Redmond, T Michael; Knapp, Daniel R; Ma, Jian-Xing; Rohrer, Barbel

    2002-10-25

    Rpe65(-/-) mice produce minimal amounts of 11-cis-retinal, the ligand necessary for the formation of photosensitive visual pigments. Therefore, the apoprotein opsin in these animals has not been exposed to its normal ligand. The Rpe65(-/-) mice contain less than 0.1% of wild type levels of rhodopsin. Mass spectrometric analysis of opsin from Rpe65(-/-) mice revealed unusually high levels of phosphorylation in dark-adapted mice but no other structural alterations. Single flash and flicker electroretinograms (ERGs) from 1-month-old animals showed trace rod function but no cone response. B-wave kinetics of the single-flash ERG are comparable with those of dark-adapted wild type mice containing a full compliment of rhodopsin. Application (intraperitoneal injection) of 11-cis-retinal to Rpe65(-/-) mice increased the rod ERG signal, increased levels of rhodopsin, and decreased opsin phosphorylation. Therefore, exogenous 11-cis-retinal improves photoreceptor function by regenerating rhodopsin and removes constitutive opsin phosphorylation. Our results indicate that opsin, which has not been exposed to 11-cis-retinal, does not generate the activity generally associated with the bleached apoprotein. PMID:12176991

  8. Generation of a genetically encoded marker of rod photoreceptor outer segment growth and renewal

    Directory of Open Access Journals (Sweden)

    John J. Willoughby

    2011-10-01

    Vertebrate photoreceptors are specialized light sensing neurons. The photoreceptor outer segment is a highly modified cilium where photons of light are transduced into a chemical and electrical signal. The outer segment has the typical cilary axoneme but, in addition, it has a large number of densely packed, stacked, intramembranous discs. The molecular and cellular mechanisms that contribute to vertebrate photoreceptor outer segment morphogenesis are still largely unknown. Unlike typical cilia, the outer segment is continuously regenerated or renewed throughout the life of the animal through the combined process of distal outer segment shedding and proximal outer segment growth. The process of outer segment renewal was discovered over forty years ago, but we still lack an understanding of how photoreceptors renew their outer segments and few, if any, molecular mechanisms that regulate outer segment growth or shedding have been described. Our lack of progress in understanding how photoreceptors renew their outer segments has been hampered by the difficulty in measuring rates of renewal. We have created a new method that uses heat-shock induction of a fluorescent protein that can be used to rapidly measure outer segment growth rates. We describe this method, the stable transgenic line we created, and the growth rates observed in larval and adult rod photoreceptors using this new method. This new method will allow us to begin to define the genetic and molecular mechanisms that regulate rod outer segment renewal, a crucial aspect of photoreceptor function and, possibly, viability.

  9. The photochemical mechanism of a B12-dependent photoreceptor protein

    Science.gov (United States)

    Kutta, Roger J.; Hardman, Samantha J. O.; Johannissen, Linus O.; Bellina, Bruno; Messiha, Hanan L.; Ortiz-Guerrero, Juan Manuel; Elías-Arnanz, Montserrat; Padmanabhan, S.; Barran, Perdita; Scrutton, Nigel S.; Jones, Alex R.

    2015-08-01

    The coenzyme B12-dependent photoreceptor protein, CarH, is a bacterial transcriptional regulator that controls the biosynthesis of carotenoids in response to light. On binding of coenzyme B12 the monomeric apoprotein forms tetramers in the dark, which bind operator DNA thus blocking transcription. Under illumination the CarH tetramer dissociates, weakening its affinity for DNA and allowing transcription. The mechanism by which this occurs is unknown. Here we describe the photochemistry in CarH that ultimately triggers tetramer dissociation; it proceeds via a cob(III)alamin intermediate, which then forms a stable adduct with the protein. This pathway is without precedent and our data suggest it is independent of the radical chemistry common to both coenzyme B12 enzymology and its known photochemistry. It provides a mechanistic foundation for the emerging field of B12 photobiology and will serve to inform the development of a new class of optogenetic tool for the control of gene expression.

  10. Knockdown of ttc26 disrupts ciliogenesis of the photoreceptor cells and the pronephros in zebrafish

    OpenAIRE

    Zhang, Qi; Liu, Qin; Austin, Chrissy; Drummond, Iain; Pierce, Eric A.

    2012-01-01

    In our effort to understand genetic disorders of the photoreceptor cells of the retina, we have focused on intraflagellar transport in photoreceptor sensory cilia. From previous mouse proteomic data we identified a cilia protein Ttc26, orthologue of dyf-13 in Caenorhabditis elegans, as a target. We localized Ttc26 to the transition zone of photoreceptor and to the transition zone of cilia in cultured murine inner medullary collecting duct 3 (mIMCD3) renal cells. Knockdown of Ttc26 in mIMCD3 c...

  11. Rhodopsin mutant P23H destabilizes rod photoreceptor disk membranes.

    Directory of Open Access Journals (Sweden)

    Mohammad Haeri

    Full Text Available Mutations in rhodopsin cause retinitis pigmentosa in humans and retinal degeneration in a multitude of other animals. We utilized high-resolution live imaging of the large rod photoreceptors from transgenic frogs (Xenopus to compare the properties of fluorescently tagged rhodopsin, Rho-EGFP, and Rho(P23H-EGFP. The mutant was abnormally distributed both in the inner and outer segments (OS, accumulating in the OS to a concentration of ∼0.1% compared to endogenous opsin. Rho(P23H-EGFP formed dense fluorescent foci, with concentrations of mutant protein up to ten times higher than other regions. Wild-type transgenic Rho-EGFP did not concentrate in OS foci when co-expressed in the same rod with Rho(P23H-EGFP. Outer segment regions containing fluorescent foci were refractory to fluorescence recovery after photobleaching, while foci in the inner segment exhibited recovery kinetics similar to OS regions without foci and Rho-EGFP. The Rho(P23H-EGFP foci were often in older, more distal OS disks. Electron micrographs of OS revealed abnormal disk membranes, with the regular disk bilayers broken into vesiculotubular structures. Furthermore, we observed similar OS disturbances in transgenic mice expressing Rho(P23H, suggesting such structures are a general consequence of mutant expression. Together these results show that mutant opsin disrupts OS disks, destabilizing the outer segment possibly via the formation of aggregates. This may render rods susceptible to mechanical injury or compromise OS function, contributing to photoreceptor loss.

  12. Mechanisms underlying stage-1 TRPL channel translocation in Drosophila photoreceptors.

    Directory of Open Access Journals (Sweden)

    Minh-Ha Lieu

    Full Text Available BACKGROUND: TRP channels function as key mediators of sensory transduction and other cellular signaling pathways. In Drosophila, TRP and TRPL are the light-activated channels in photoreceptors. While TRP is statically localized in the signaling compartment of the cell (the rhabdomere, TRPL localization is regulated by light. TRPL channels translocate out of the rhabdomere in two distinct stages, returning to the rhabdomere with dark-incubation. Translocation of TRPL channels regulates their availability, and thereby the gain of the signal. Little, however, is known about the mechanisms underlying this trafficking of TRPL channels. METHODOLOGY/PRINCIPAL FINDINGS: We first examine the involvement of de novo protein synthesis in TRPL translocation. We feed flies cycloheximide, verify inhibition of protein synthesis, and test for TRPL translocation in photoreceptors. We find that protein synthesis is not involved in either stage of TRPL translocation out of the rhabdomere, but that re-localization to the rhabdomere from stage-1, but not stage-2, depends on protein synthesis. We also characterize an ex vivo eye preparation that is amenable to biochemical and genetic manipulation. We use this preparation to examine mechanisms of stage-1 TRPL translocation. We find that stage-1 translocation is: induced with ATP depletion, unaltered with perturbation of the actin cytoskeleton or inhibition of endocytosis, and slowed with increased membrane sterol content. CONCLUSIONS/SIGNIFICANCE: Our results indicate that translocation of TRPL out of the rhabdomere is likely due to protein transport, and not degradation/re-synthesis. Re-localization from each stage to the rhabdomere likely involves different strategies. Since TRPL channels can translocate to stage-1 in the absence of ATP, with no major requirement of the cytoskeleton, we suggest that stage-1 translocation involves simple diffusion through the apical membrane, which may be regulated by release of a

  13. Unique system of photoreceptors in sea urchin tube feet

    Science.gov (United States)

    Ullrich-Lüter, Esther M; Dupont, Sam; Arboleda, Enrique; Hausen, Harald; Arnone, Maria Ina

    2011-01-01

    Different sea urchin species show a vast variety of responses to variations in light intensity; however, despite this behavioral evidence for photosensitivity, light sensing in these animals has remained an enigma. Genome information of the recently sequenced purple sea urchin (Strongylocentrotus purpuratus) allowed us to address this question from a previously unexplored molecular perspective by localizing expression of the rhabdomeric opsin Sp-opsin4 and Sp-pax6, two genes essential for photoreceptor function and development, respectively. Using a specifically designed antibody against Sp-Opsin4 and in situ hybridization for both genes, we detected expression in two distinct groups of photoreceptor cells (PRCs) located in the animal's numerous tube feet. Specific reactivity of the Sp-Opsin4 antibody with sea star optic cushions, which regulate phototaxis, suggests a similar visual function in sea urchins. Ultrastructural characterization of the sea urchin PRCs revealed them to be of a microvillar receptor type. Our data suggest that echinoderms, in contrast to chordates, deploy a microvillar, r-opsin–expressing PRC type for vision, a feature that has been so far documented only in protostome animals. Surprisingly, sea urchin PRCs lack any associated screening pigment. Indeed, one of the tube foot PRC clusters may account for directional vision by being shaded through the opaque calcite skeleton. The PRC axons connect to the animal internal nervous system, suggesting an integrative function beyond local short circuits. Because juveniles display no phototaxis until skeleton completion, we suggest a model in which the entire sea urchin, deploying its skeleton as PRC screening device, functions as a huge compound eye. PMID:21536888

  14. Transfection by DNAs of avian erythroblastosis virus and avian myelocytomatosis virus strain MC29.

    OpenAIRE

    Copeland, N G; Cooper, G M

    1980-01-01

    Chicken embryo fibroblasts and NIH 3T3 mouse cells were transformable by DNAs of chicken cells infected with avian myelocytomatosis virus strain MC29 or with avian erythroblastosis virus. Transfection of chicken cells appeared to require replication of MC29 or avian erythroblastosis virus in the presence of a nontransforming helper virus. In contrast, NIH 3T3 cells transformed by MC29 or avian erythroblastosis virus DNA contained only replication-defective transforming virus genomes.

  15. Complex geometry of quantum cones

    Energy Technology Data Exchange (ETDEWEB)

    Brzezinski, T. [Department of Mathematics, Swansea University, Swansea SA2 8PP (United Kingdom)

    2014-09-11

    The algebras obtained as fixed points of the action of the cyclic group Z{sub N} on the coordinate algebra of the quantum disc are studied. These can be understood as coordinate algebras of quantum or non-commutative cones. The following observations are made. First, contrary to the classical situation, the actions of Z{sub N} are free and the resulting algebras are homologically smooth. Second, the quantum cone algebras admit differential calculi that have all the characteristics of calculi on smooth complex curves. Third, the corresponding volume forms are exact, indicating that the constructed algebras describe manifolds with boundaries. (Copyright copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. IPR Modeling for Coning Wells

    OpenAIRE

    Astutik, Wynda

    2012-01-01

    In this study, based on the work of Vogel, we generated the Inflow Performance Relationship (IPR) curves and its dimensionless form at any stage of depletion using black-oil simulator results. The IPR was generated for horizontal well with gas and water coning problems, producing from thin oil reservoir sandwiched between gas cap and aquifer. Two empirical IPR equations adopted from SPE paper by Whitson was also presented here. The first empirical relationship was developed based on simulated...

  17. Chymotrypsin and trypsin sensitivities of avian reoviruses.

    OpenAIRE

    Drastini, Y; McKenna, P K; Kibenge, F S; Lopez, A

    1994-01-01

    Experiments were undertaken to examine the chymotrypsin sensitivity and trypsin sensitivity of 13 avian reoviruses, and to determine if there was any correlation with pathogenicity of some chicken reoviruses. A wide variation in the degree of sensitivity of avian reoviruses to chymotrypsin and trypsin was observed. Overall, the infectivity of the 13 avian reoviruses for Vero cells was markedly reduced by treatment with 0.01% chymotrypsin (the lowest concentration tested) while 0.5% trypsin si...

  18. Light-cone quantization of quantum chromodynamics

    International Nuclear Information System (INIS)

    We discuss the light-cone quantization of gauge theories from two perspectives: as a calculational tool for representing hadrons as QCD bound-states of relativistic quarks and gluons, and also as a novel method for simulating quantum field theory on a computer. The light-cone Fock state expansion of wavefunctions at fixed light cone time provides a precise definition of the parton model and a general calculus for hadronic matrix elements. We present several new applications of light-cone Fock methods, including calculations of exclusive weak decays of heavy hadrons, and intrinsic heavy-quark contributions to structure functions. A general nonperturbative method for numerically solving quantum field theories, ''discretized light-cone quantization,'' is outlined and applied to several gauge theories, including QCD in one space and one time dimension, and quantum electrodynamics in physical space-time at large coupling strength. The DLCQ method is invariant under the large class of light-cone Lorentz transformations, and it can be formulated such at ultraviolet regularization is independent of the momentum space discretization. Both the bound-state spectrum and the corresponding relativistic light-cone wavefunctions can be obtained by matrix diagonalization and related techniques. We also discuss the construction of the light-cone Fock basis, the structure of the light-cone vacuum, and outline the renormalization techniques required for solving gauge theories within the light-cone Hamiltonian formalism

  19. Light-cone quantization of quantum chromodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)); Pauli, H.C. (Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany, F.R.))

    1991-06-01

    We discuss the light-cone quantization of gauge theories from two perspectives: as a calculational tool for representing hadrons as QCD bound-states of relativistic quarks and gluons, and also as a novel method for simulating quantum field theory on a computer. The light-cone Fock state expansion of wavefunctions at fixed light cone time provides a precise definition of the parton model and a general calculus for hadronic matrix elements. We present several new applications of light-cone Fock methods, including calculations of exclusive weak decays of heavy hadrons, and intrinsic heavy-quark contributions to structure functions. A general nonperturbative method for numerically solving quantum field theories, discretized light-cone quantization,'' is outlined and applied to several gauge theories, including QCD in one space and one time dimension, and quantum electrodynamics in physical space-time at large coupling strength. The DLCQ method is invariant under the large class of light-cone Lorentz transformations, and it can be formulated such at ultraviolet regularization is independent of the momentum space discretization. Both the bound-state spectrum and the corresponding relativistic light-cone wavefunctions can be obtained by matrix diagonalization and related techniques. We also discuss the construction of the light-cone Fock basis, the structure of the light-cone vacuum, and outline the renormalization techniques required for solving gauge theories within the light-cone Hamiltonian formalism.

  20. Molecular characterization of Indonesia avian influenza virus

    OpenAIRE

    N.L.P.I Dharmayanti; R Damayanti; R Indriani; A Wiyono; R.M.A Adjid

    2005-01-01

    Avian influenza outbreaks in poultry have been reported in Java island since August 2003. A total of 14 isolates of avian influenza virus has been isolated from October 2003 to October 2004. The viruses have been identified as HPAI H5N1 subtype. All of them were characterized further at genetic level and also for their pathogenicity. Phylogenetic analysis showed all of the avian influenza virus isolates were closely related to avian influenza virus from China (A/Duck/China/E319-2/03(H5N1). Mo...

  1. Avian Influenza infection in Human

    Directory of Open Access Journals (Sweden)

    Mohan. M

    2008-08-01

    Full Text Available Outbreaks caused by the H5N1 strain are presently of the greatest concern for human health. In assessing risks to human health, it is important to know exactly which avian virus strains are causing the outbreaks in birds.All available evidence points to an increased risk of transmission to humans when outbreaks of highly pathogenic avian H5N1 influenza are widespread in poultry. There is mounting evidence that this strain has a unique capacity to jump the species barrier and cause severe disease, with high mortality, in humans. There is no evidence, to date that efficient human to human transmission of H5N1 strain has occurred and very often. Efficient transmission among humans is a key property of pandemic strains and a property that the avian H5N1 and H9N2 viruses apparently lacked. The biological and molecular basis for effective aerosol transmission among humans is not known. The virus can improve its transmissibility among humans via two principal mechanisms. The first is a “reassortment” event, in which genetic material is exchanged between human and avian viruses during co-infection of a human or pig.Reassortment could result in a fully transmissible pandemic virus, announced by a sudden surge of cases with explosive spread. The second mechanism is a more gradual process of adaptive mutation, whereby the capability of the virus to bind to human cells increases during subsequent infections of humans. Adaptive mutation, expressed initially as small clusters of human cases with some evidence of human-to-human transmission, would probably give the world some time to take defensive action, if detected sufficiently early. As the number of human infections grows, the risk increases that a new virus subtype could emerge, triggering an influenza pandemic. Humans as well as swine must now be considered a potential mixing vessel for the generation of such a virus. This link between widespread infection in poultry and increased risk of human

  2. A new family of Greek origin maps to the CRD locus for autosomal dominant cone-rod dystrophy on 19q.

    OpenAIRE

    Papaioannou, M.; BESSANT, D.; Payne, A.; Bellingham, J.; Rougas, C; Loutradis-Anagnostou, A; Gregory-Evans, C; Balassopoulou, A; Bhattacharya, S.

    1998-01-01

    Retinal photoreceptor dystrophies (RD) are a highly heterogeneous group of genetic disorders of the retina, representing the most frequently inherited form of visual handicap, affecting approximately 1.5 million people world wide. To date, more than 40 genetic loci have been implicated in RD. One of them, the CORD2 locus, for an autosomal dominant form of cone-rod dystrophy (CRD), maps to chromosome 19q and has previously been reported in a single large family of British origin. We now report...

  3. Bicarbonate and Ca2+ sensing modulators activate photoreceptor ROS-GC1 synergistically

    Directory of Open Access Journals (Sweden)

    Teresa eDuda

    2016-01-01

    Full Text Available Photoreceptor ROS-GC1, a prototype subfamily member of the membrane guanylate cyclase family, is a central component of phototransduction. It is a single transmembrane-spanning protein, composed of modular blocks. In rods, guanylate cyclase activating proteins (GCAPs 1 and 2 bind to its juxtamembrane domain and the C-terminal extension, respectively, to accelerate cyclic GMP synthesis when Ca2+ levels are low. In cones, the additional expression of the Ca2+-dependent guanylate cyclase activating protein (CD-GCAP S100B which binds to its C-terminal extension, supports acceleration of cyclic GMP synthesis at high Ca2+ levels. Independent of Ca2+, ROS-GC1 activity is also stimulated directly by bicarbonate binding to the core catalytic domain. Several enticing molecular features of this transduction system are revealed in the present study. In combination, bicarbonate and Ca2+-dependent modulators raised maximal ROS-GC activity to levels that exceeded the sum of their individual effects. The F514S mutation in ROS-GC1 that causes blindness in type 1 Leber’s congenital amaurosis severely reduced basal ROS-GC1 activity. GCAP2 and S100B Ca2+ signaling modes remained functional, while the GCAP1-modulated mode was diminished. Bicarbonate nearly restored basal activity as well as GCAP2- and S100B-stimulated activities of the F514S mutant to normal levels but could not resurrect GCAP1 stimulation. We conclude that GCAP1 and GCAP2 forge distinct pathways through domain-specific modules of ROS-GC1 whereas the S100B and GCAP2 pathways may overlap. The synergistic interlinking of bicarbonate to GCAPs- and S100B-modulated pathways intensifies and tunes the dependence of cyclic GMP synthesis on intracellular Ca2+. Our study challenges the recently proposed GCAP1 and GCAP2 overlapping phototransduction model (Peshenko, I.V., Olshevskaya, and Dizhoor, A. M. (2015 J Biol. Chem 290, 6913-6924.

  4. Climate change and avian influenza

    OpenAIRE

    Gilbert, Marius; Slingenbergh, Jan; Xiao, Xiangming

    2008-01-01

    This paper discusses impacts of climate change on the ecology of avian influenza viruses (AI viruses), which presumably co-evolved with migratory water birds, with virus also persisting outside the host in subarctic water bodies. Climate change would almost certainly alter bird migration, influence the AI virus transmission cycle and directly affect virus survival outside the host. The joint, net effects of these changes are rather unpredictable, but it is likely that AI virus circulation in ...

  5. Simulating Avian Wingbeats and Wakes

    OpenAIRE

    Parslew, Ben

    2012-01-01

    Analytical models of avian flight have previously been used to predict mechanical and metabolic power consumption during cruise. These models are limited, in that they neglect details of wing kinematics, and model power by assuming a fixed or rotary wing (actuator disk) weight support mechanism. Theoretical methods that incorporate wing kinematics potentially offer more accurate predictions of power consumption by calculating instantaneous aerodynamic loads on the wing. However, the success o...

  6. Avian zoonoses – a review

    OpenAIRE

    Kozdruń Wojciech; Czekaj Hanna; Styś Natalia

    2015-01-01

    Birds are one of the most interesting and most colourful groups of animals, but they can also be a source of zoonotic factors dangerous for humans. This paper describes the threats to human health from contact with birds. The most vulnerable occupational groups associated with birds are veterinarians, owners of poultry farms, breeders of ornamental birds, zoo personnel, and poultry slaughterhouse workers. Ornithosis is the most dangerous zoonosis of the avian bacterial diseases. Among other h...

  7. Using EGEE against avian flu

    CERN Multimedia

    2006-01-01

    During April 2006 avian flu was spreading across the world with the potential of turning into a pandemic, a drug to treat the deadly H5N1 strain was needed. Such a task required the huge processing power provided by EGEE, which analysed 300 000 possible drug components for their suitability. This map shows the network of computer centres and their activity during this time.

  8. The ultra-structural survey of Aloe Vera extract on photoreceptor layer after methanol intoxication

    OpenAIRE

    M Bahramian; A. Amiri; A zarenezhad; M mard khoshnood; E zarenezhad; Esfandiari, A

    2015-01-01

    Background & aim: The photoreceptor layer is a main part of the retina. The Aloe Vera has antioxidant, antibacterial and antidiabetic effects. The aim of this study was to investigate the ultra-structure of the photoreceptor layer of male rats under the effect of methanol intoxication and protective effects of Aloe Vera extract against the methanol toxicity. Methods: The present experimental study was conducted on 30 adult male wistar rats in three groups of ten: as control, methanol intoxica...

  9. Depth-resolved rhodopsin molecular contrast imaging for functional assessment of photoreceptors

    OpenAIRE

    Tan Liu; Rong Wen; Lam, Byron L.; Puliafito, Carmen A.; Shuliang Jiao

    2015-01-01

    Rhodopsin, the light-sensing molecule in the outer segments of rod photoreceptors, is responsible for converting light into neuronal signals in a process known as phototransduction. Rhodopsin is thus a functional biomarker for rod photoreceptors. Here we report a novel technology based on visible-light optical coherence tomography (VIS-OCT) for in vivo molecular imaging of rhodopsin. The depth resolution of OCT allows the visualization of the location where the change of optical absorption oc...

  10. Large variation among photoreceptors as the basis of visual flexibility in the common backswimmer

    OpenAIRE

    Immonen, Esa-Ville; Ignatova, Irina; Gislen, Anna; Warrant, Eric; Vähäsöyrinki, Mikko; Weckström, Matti; Frolov, Roman

    2014-01-01

    The common backswimmer, Notonecta glauca, uses vision by day and night for functions such as underwater prey animal capture and flight in search of new habitats. Although previous studies have identified some of the physiological mechanisms facilitating such flexibility in the animal's vision, neither the biophysics of Notonecta photoreceptors nor possible cellular adaptations are known. Here, we studied Notonecta photoreceptors using patch-clamp and intracellular recording methods. Photorece...

  11. Dynactin is required to maintain nuclear position within postmitotic Drosophila photoreceptor neurons

    OpenAIRE

    Whited, Jessica L.; Cassell, Andre; Brouillette, Monique; Garrity, Paul A.

    2004-01-01

    How a nucleus is positioned within a highly polarized post-mitotic animal cell is not well understood. In this work, we demonstrate that the Dynactin complex (a regulator of the microtubule motor protein Dynein) is required to maintain the position of the nucleus within post-mitotic Drosophila melanogaster photoreceptor neurons. We show that multiple independent disruptions of Dynactin function cause a relocation of the photoreceptor nucleus toward the brain, and that inhibiting Dynactin caus...

  12. The influence of photoreceptor size and distribution on optical sensitivity in the eyes of lanternfishes (Myctophidae)

    KAUST Repository

    de Busserolles, Fanny

    2014-06-13

    The mesopelagic zone of the deep-sea (200-1000 m) is characterised by exponentially diminishing levels of downwelling sunlight and by the predominance of bioluminescence emissions. The ability of mesopelagic organisms to detect and behaviourally react to downwelling sunlight and/or bioluminescence will depend on the visual task and ultimately on the eyes and their capacity for detecting low levels of illumination and intermittent point sources of bioluminescent light. In this study, we investigate the diversity of the visual system of the lanternfish (Myctophidae). We focus specifically on the photoreceptor cells by examining their size, arrangement, topographic distribution and contribution to optical sensitivity in 53 different species from 18 genera. We also examine the influence(s) of both phylogeny and ecology on these photoreceptor variables using phylogenetic comparative analyses in order to understand the constraints placed on the visual systems of this large group of mesopelagic fishes at the first stage of retinal processing. We report great diversity in the visual system of the Myctophidae at the level of the photoreceptors. Photoreceptor distribution reveals clear interspecific differences in visual specialisations (areas of high rod photoreceptor density), indicating potential interspecific differences in interactions with prey, predators and/or mates. A great diversity in photoreceptor design (length and diameter) and density is also present. Overall, the myctophid eye is very sensitive compared to other teleosts and each species seems to be specialised for the detection of a specific signal (downwelling light or bioluminescence), potentially reflecting different visual demands for survival. Phylogenetic comparative analyses highlight several relationships between photoreceptor characteristics and the ecological variables tested (depth distribution and luminous tissue patterns). Depth distribution at night was a significant factor in most of the

  13. A mammalian neural tissue opsin (Opsin 5) is a deep brain photoreceptor in birds

    OpenAIRE

    Nakane, Yusuke; IKEGAMI, Keisuke; Ono, Hiroko; YAMAMOTO, Naoyuki; Yoshida, Shosei; Hirunagi, Kanjun; Ebihara, Shizufumi; Kubo, Yoshihiro; Yoshimura, Takashi

    2010-01-01

    It has been known for many decades that nonmammalian vertebrates detect light by deep brain photoreceptors that lie outside the retina and pineal organ to regulate seasonal cycle of reproduction. However, the identity of these photoreceptors has so far remained unclear. Here we report that Opsin 5 is a deep brain photoreceptive molecule in the quail brain. Expression analysis of members of the opsin superfamily identified as Opsin 5 (OPN5; also known as Gpr136, Neuropsin, PGR12, and TMEM13) m...

  14. Genetic Interaction of Centrosomin and Bazooka in Apical Domain Regulation in Drosophila Photoreceptor

    OpenAIRE

    Chen, Geng; Rogers, Alicia K.; League, Garrett P.; Nam, Sang-Chul

    2011-01-01

    Background Cell polarity genes including Crumbs (Crb) and Par complexes are essential for controlling photoreceptor morphogenesis. Among the Crb and Par complexes, Bazooka (Baz, Par-3 homolog) acts as a nodal component for other cell polarity proteins. Therefore, finding other genes interacting with Baz will help us to understand the cell polarity genes' role in photoreceptor morphogenesis. Methodology/Principal Findings Here, we have found a genetic interaction between baz and centrosomin (c...

  15. Genome-wide analysis of light-regulated alternative splicing mediated by photoreceptors in Physcomitrella patens

    OpenAIRE

    Wu, Hshin-Ping; Su, Yi-shin; Chen, Hsiu-Chen; Chen, Yu-Rong; Wu, Chia-Chen; Lin, Wen-Dar; Tu, Shih-Long

    2014-01-01

    Background Light is one of the most important factors regulating plant growth and development. Light-sensing photoreceptors tightly regulate gene expression to control photomorphogenic responses. Although many levels of gene expression are modulated by photoreceptors, regulation at the mRNA splicing step remains unclear. Results We performed high-throughput mRNA sequencing to analyze light-responsive changes in alternative splicing in the moss Physcomitrella patens, and found that a large num...

  16. Avian zoonoses – a review

    Directory of Open Access Journals (Sweden)

    Kozdruń Wojciech

    2015-06-01

    Full Text Available Birds are one of the most interesting and most colourful groups of animals, but they can also be a source of zoonotic factors dangerous for humans. This paper describes the threats to human health from contact with birds. The most vulnerable occupational groups associated with birds are veterinarians, owners of poultry farms, breeders of ornamental birds, zoo personnel, and poultry slaughterhouse workers. Ornithosis is the most dangerous zoonosis of the avian bacterial diseases. Among other hazardous bacterial factors, Salmonella and Campylobacter are responsible for gastrointestinal diseases. Avian influenza is the most dangerous of the viral diseases. It should be noted, however, that avian influenza is a disease of birds, not humans. The recent threat which has appeared is infection with West Nile virus. The results of serological examinations of birds and humans indicate that the virus exists in our ecosystem. Allergic alveolitis connected with the pigeon tick and the Dermanyssus gallinae mite also merits mention. In any case, where people have contact with birds or their droppings and secretions, special precautions should be taken. This way the negative effects of birds on human health can be minimised or eliminated

  17. Photobiomodulation reduces photoreceptor death and regulates cytoprotection in early states of P23H retinal dystrophy

    Science.gov (United States)

    Kirk, Diana K.; Gopalakrishnan, Sandeep; Schmitt, Heather; Abroe, Betsy; Stoehr, Michele; Dubis, Adam; Carroll, Joseph; Stone, Jonathan; Valter, Krisztina; Eells, Janis

    2013-03-01

    Irradiation by light in the far-red to near-infrared (NIR) region of the spectrum (photobiomodulation, PBM) has been demonstrated to attenuate the severity of neurodegenerative disease in experimental and clinical studies. The purpose of this study was to test the hypothesis that 670 nm PBM would protect against the loss of retinal function and improve photoreceptor survival in a rodent model of retinitis pigmentosa, the P23H transgenic rat. P23H rat pups were treated once per day with a 670 nm LED array (180 sec treatments at 50 mW/cm2; fluence 9 joules/cm2) (Quantum Devices Inc., Barneveld WI) from postnatal day (p) 16-20 or from p10-20. Sham-treated rats were restrained, but not exposed to NIR light. The status of the retina was determined at p22 by assessment of mitochondrial function, oxidative stress and cell death. In a second series of studies, retinal status was assessed at p30 by measuring photoreceptor function by ERG and retinal morphology by Spectral Domain Optical Coherence Tomography (SD-OCT). 670 nm PBM increased retinal mitochondrial cytochrome oxidase activity and upregulated the retina's production of the key mitochondrial antioxidant enzyme, MnSOD. PBM also attenuated photoreceptor cell loss and improved photoreceptor function. PBM protects photoreceptors in the developing P23H retina, by augmenting mitochondrial function and stimulating antioxidant protective pathways. Photobiomodulation may have therapeutic potential, where mitochondrial damage is a step in the death of photoreceptors.

  18. Variable Light-Cone Theory of Gravity

    OpenAIRE

    Drummond, I T

    1999-01-01

    We show how to reformulate Variable Speed of Light Theories (VSLT) in a covariant fashion as Variable Light-Cone Theories (VLCT) by introducing two vierbein bundles each associated with a distinct metric. The basic gravitational action relates to one bundle while matter propagates relative to the other in a conventional way. The variability of the speed of light is represented by the variability of the matter light-cone relative to the gravitational light-cone. The two bundles are related loc...

  19. g-Weak Contraction in Ordered Cone Rectangular Metric Spaces

    Directory of Open Access Journals (Sweden)

    S. K. Malhotra

    2013-01-01

    Full Text Available We prove some common fixed-point theorems for the ordered g-weak contractions in cone rectangular metric spaces without assuming the normality of cone. Our results generalize some recent results from cone metric and cone rectangular metric spaces into ordered cone rectangular metric spaces. Examples are provided which illustrate the results.

  20. Vacuum Compatible Percussive Dynamic Cone Penetrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Honeybee Robotics proposes to develop a vacuum compatible percussive dynamic cone penetrometer (PDCP), for establishing soil bin characteristics, with the ultimate...

  1. Logarithmic barriers for sparse matrix cones

    CERN Document Server

    Andersen, Martin S; Vandenberghe, Lieven

    2012-01-01

    Algorithms are presented for evaluating gradients and Hessians of logarithmic barrier functions for two types of convex cones: the cone of positive semidefinite matrices with a given sparsity pattern, and its dual cone, the cone of sparse matrices with the same pattern that have a positive semidefinite completion. Efficient large-scale algorithms for evaluating these barriers and their derivatives are important in interior-point methods for nonsymmetric conic formulations of sparse semidefinite programs. The algorithms are based on the multifrontal method for sparse Cholesky factorization.

  2. Rod-cone interactions and the temporal impulse response of the cone pathway

    OpenAIRE

    Zele, Andrew J.; Cao, Dingcai; Pokorny, Joel

    2008-01-01

    Dark-adapted rods suppress cone-mediated flicker detection. This study evaluates the effect that rod activity has on cone temporal processing by investigating whether rod mediated suppression changes the cone pathway impulse response function, regardless of the form of the temporal signal. Stimuli were generated with a 2-channel photostimulator that has four primaries for the central field and four primaries for the surround. Cone pathway temporal impulse response functions were derived from ...

  3. Correlation Between Cone Penetration Rate And Measured Cone Penetration Parameters In Silty Soils

    DEFF Research Database (Denmark)

    Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2013-01-01

    This paper shows, how a change in cone penetration rate affects the cone penetration measurements, hence the cone resistance, pore pressure, and sleeve friction in silty soil. The standard rate of penetration is 20 mm/s, and it is generally accepted that undrained penetration occurs in clay while...

  4. Avian influenza and the poultry trade

    OpenAIRE

    Nicita, Alessandro

    2008-01-01

    Because of high mortality rates, high rates of contagion, and the possibility of cross-species infection to mammals including humans, high pathogenic avian influenza is a major concern both to consumers and producers of poultry. The implications of the avian influenza for international poultry markets are large and include the loss of consumer confidence, loss of competitiveness, loss of m...

  5. Atypical Avian Influenza (H5N1)

    OpenAIRE

    Apisarnthanarak, Anucha; Kitphati, Rungrueng; Thongphubeth, Kanokporn; Patoomanunt, Prisana; Anthanont, Pimjai; Auwanit, Wattana; Thawatsupha, Pranee; Chittaganpitch, Malinee; Saeng-Aroon, Siriphan; Waicharoen, Sunthareeya; Apisarnthanarak, Piyaporn; Storch, Gregory A.; Mundy, Linda M.; Fraser, Victoria J.

    2004-01-01

    We report the first case of avian influenza in a patient with fever and diarrhea but no respiratory symptoms. Avian influenza should be included in the differential diagnosis for patients with predominantly gastrointestinal symptoms, particularly if they have a history of exposure to poultry.

  6. 76 FR 24793 - Highly Pathogenic Avian Influenza

    Science.gov (United States)

    2011-05-03

    ... (76 FR 4046-4056, Docket No. APHIS-2006-0074) an interim rule that amended the regulations governing... Inspection Service 9 CFR Parts 93, 94, and 95 RIN 0579-AC36 Highly Pathogenic Avian Influenza AGENCY: Animal... products from regions where any subtype of highly pathogenic avian influenza is considered to exist....

  7. A brief introduction to avian influenza virus

    Science.gov (United States)

    Avian influenza virus (AIV) causes a disease of high economic importance for poultry production worldwide. The earliest recorded cases of probable high pathogenicity AIV in poultry were reported in Italy in the 1870’s and avian influenza been recognized in domestic poultry through the modern era of ...

  8. The global nature of avian influenza

    Science.gov (United States)

    Avian influenza virus is a global virus which knows no geographic boundaries, has no political agenda, and can infect poultry irrespective of their agricultural or anthropocentric production systems. Avian influenza viruses or evidence of their infection have been detected in poultry and wild birds...

  9. Nested-cone transformer antenna

    Science.gov (United States)

    Ekdahl, Carl A.

    1991-01-01

    A plurality of conical transmission lines are concentrically nested to form n output antenna for pulsed-power, radio-frequency, and microwave sources. The diverging conical conductors enable a high power input density across a bulk dielectric to be reduced below a breakdown power density at the antenna interface with the transmitting medium. The plurality of cones maintain a spacing between conductors which minimizes the generation of high order modes between the conductors. Further, the power input feeds are isolated at the input while enabling the output electromagnetic waves to add at the transmission interface. Thus, very large power signals from a pulse rf, or microwave source can be radiated.

  10. Gravity duals of boundary cones

    CERN Document Server

    Camps, Joan

    2016-01-01

    The replica trick defines Renyi entropies as partition functions on conically singular geometries. We discuss their gravity duals: regular bulk solutions to the Einstein equations inducing conically singular metrics at the boundary. When the conical singularity is supported on a flat or spherical surface, these solutions are rewritings of the hyperbolic black hole. For more general shapes, these solutions are new. We construct them perturbatively in a double expansion in the distance and strength of the conical singularity, and extract the vacuum polarisation due to the cone. Recent results about the structure of logarithmic divergences of Renyi entropies are reproduced ---in particular, $f_b\

  11. Seawave Slot-Cone Generator

    DEFF Research Database (Denmark)

    Vicinanza, Diego; Margheritini, Lucia; Contestabile, Pasquale;

    2009-01-01

    This paper discusses a new type of Wave Energy Converter (WEC) named Seawave Slot-Cone Generator (SSG). The SSG is a WEC of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level in which the water of incoming waves is stored...... temporary. Using this method practically all waves, regardless of size and speed are captured for energy production. In each reservoir, expressively designed low head hydro-turbines are converting the potential energy of the stored water into electrical power. A key to success for the SSG will be low cost...

  12. Gene therapy rescues photoreceptor blindness in dogs and paves the way for treating human X-linked retinitis pigmentosa

    OpenAIRE

    Beltran, William A.; Artur V Cideciyan; Lewin, Alfred S.; Iwabe, Simone; Khanna, Hemant; Sumaroka, Alexander; Chiodo, Vince A.; Fajardo, Diego S; Román, Alejandro J.; Deng, Wen-Tao; Swider, Malgorzata; Alemán, Tomas S.; Boye, Sanford L.; Genini, Sem; Swaroop, Anand

    2012-01-01

    Hereditary retinal blindness is caused by mutations in genes expressed in photoreceptors or retinal pigment epithelium. Gene therapy in mouse and dog models of a primary retinal pigment epithelium disease has already been translated to human clinical trials with encouraging results. Treatment for common primary photoreceptor blindness, however, has not yet moved from proof of concept to the clinic. We evaluated gene augmentation therapy in two blinding canine photoreceptor diseases that model...

  13. Gibberellin and Auxin Influence the Diurnal Transcription Pattern of Photoreceptor Genes via CRY1a in Tomato

    OpenAIRE

    Facella, Paolo; Daddiego, Loretta; Giuliano, Giovanni; Perrotta, Gaetano

    2012-01-01

    Background Plant photoreceptors, phytochromes and cryptochromes, regulate many aspects of development and growth, such as seed germination, stem elongation, seedling de-etiolation, cotyledon opening, flower induction and circadian rhythms. There are several pieces of evidence of interaction between photoreceptors and phyto-hormones in all of these physiological processes, but little is known about molecular and genetic mechanisms underlying hormone-photoreceptor crosstalk. Methodology/Princip...

  14. Molecular patterns of avian influenza A viruses

    Institute of Scientific and Technical Information of China (English)

    KOU Zheng; LEI FuMin; WANG ShengYue; ZHOU YanHong; LI TianXian

    2008-01-01

    Avian influenza A viruses could get across the species barrier and be fatal to humans. Highly patho-genic avian influenza H5N1 virus was an example. The mechanism of interspecies transmission is not clear as yet. In this research, the protein sequences of 237 influenza A viruses with different subtypes were transformed into pseudo-signals. The energy features were extracted by the method of wavelet packet decomposition and used for virus classification by the method of hierarchical clustering. The clustering results showed that five patterns existed in avian influenza A viruses, which associated with the phenotype of interspecies transmission, and that avian viruses with patterns C and E could across species barrier and those with patterns A, B and D might not have the abilities. The results could be used to construct an early warning system to predict the transmissibility of avian influenza A viruses to humans.

  15. Cryoconservation of avian gonads in Canada.

    Science.gov (United States)

    Silversides, F G; Robertson, M C; Liu, J

    2013-10-01

    Avian genetic resources have declined dramatically over the past half century as the cost of maintaining populations has exceeded the perceived benefit of keeping them. Despite the early importance of poultry in the development of cryopreservation techniques, very little avian germplasm has been conserved. Cryopreservation and recovery of avian gonads preserve the W chromosome and overcome problems of freezing and recovering semen or conserving and manipulating embryonic cells, and the use of vitrification procedures for preserving gonads minimizes cellular damage. On the basis of research demonstrating the biological possibility of cryopreserving and transplanting avian gonads, 5,125 testicles and 2,667 ovaries from 10 populations of Japanese quail, 9 populations of chickens, and 1 population of Chilean tinamou were cryopreserved and sent to the Canadian Animal Genetic Resources program for long-term storage. These gonads represent 20 of the 33 distinct avian populations currently maintained at Canadian public institutions of agricultural research. PMID:24046407

  16. A study on photoreceptor by using the effect of additives

    International Nuclear Information System (INIS)

    We have been studied photosensitization mechanism's additive effect, of perylene 3,4,9,10-tetracarboxyl-diimide and X-phthalocyanine (charge generation materials), using the photochemical and photoelectrochemical approach. It was found that the photoreceptor on the excited state reacts with metal oxide, which creates the charge transfer on the interface of SnO2/electrolyte. In the electrode (X5P1) made of five X-phthalocyanine and single perylene 3,4,9,10-tetracarboxyldiimide layers, the cathodic photocurrent of X-phthalocyanine in the 400-600 nm region was increased by the addition of perylene 3,4,9,10-tetracarboxyldiimide. The maximum wavelength of fluorescence of perylene 3,4,9,10-tetracarboxyldiimide showed no dependence on the temperature. The addition of 4-dibenzylamino-2-methylbenzaldehyde diphenylhydrazone known as charge transport material was represented as decreasing photocurrent for X-phthalocyanine and perylene 3,4,9,10-tetracarboxyldiimide, respectively. In the electrode (X1P1) made of single X-phthalocyanine and single perylene 3,4,9,10-tetracarboxyldiimide layers, an anodic photocurrent of about 10.5 nA was generated by addition of hydroquinone at 550 nm. And the characteristic of photoinduced discharge was shown to decrease by a factor 5 and the speed of dark decay was increased by a factor of 1.2

  17. Mapping of the human cone transducin {alpha} subunit (GNAT2) gene to 1p13 and mutation analysis in patients with Stargardt`s disease

    Energy Technology Data Exchange (ETDEWEB)

    Magovcevic, I.; Weremowicz, S.; Morton, C.C. [Harvard Medical School, Boston, MA (United States)] [and others

    1994-09-01

    Transducin {alpha} subunits are members of a large family of G-proteins and play an important role in phototransduction in rod and cone photoreceptors. We report the localization of the human cone {alpha} transducin (GNAT2) gene using fluorescence in situ hybridization (FISH) on chromosome 1 in band p13. The recent assignment of a gene for Stargardt`s disease to the same chromosomal region by linkage analysis prompted us to investigate the possible role of GNAT2 in the pathogenesis of this disease. Stargardt`s disease is characterized by degeneration in late childhood or early adulthood of the macula of the retina, a region rich in cones. We screened patients with Stargardt`s disease, with or without peripheral cone involvement as monitored by the full-field ERG, for mutations in this gene. We investigated 66 unrelated patients including 22 with peripheral cone dysfunction for mutations in the coding region of the GNAT2 gene using polymerase chain reaction-single strand conformation polymorphism analysis (SSCP) and direct sequencing. One patient (034-16) was heterozygous for a silent change in exon VI, Asp238Asp (GAT to GAC). Two patients, one (035-005) with peripheral cone involvement and one (071-001) without peripheral cone involvement, were heterozygous for the missense change Val124Met (GTG to ATG) in exon IV. A subsequent screen of 96 unrelated, unaffected controls revealed one individual (N10) who was also heterozygous for the Val124Met alteration. We concluded that Asp238Asp and Val124Met are rare variants not causing Stargardt`s disease. Hence, no disease-specific mutations were found indicating that GNAT2 is probably not involved in the pathogenesis of most cases of Stargardt`s disease.

  18. An alternative pathway for signal flow from rod photoreceptors to ganglion cells in mammalian retina.

    OpenAIRE

    DeVries, S H; Baylor, D A

    1995-01-01

    Rod signals in the mammalian retina are thought to reach ganglion cells over the circuit rod-->rod depolarizing bipolar cell-->AII amacrine cell-->cone bipolar cells-->ganglion cells. A possible alternative pathway involves gap junctions linking the rods and cones, the circuit being rod-->cone-->cone bipolar cells-->ganglion cells. It is not clear whether this second pathway indeed relays rod signals to ganglion cells. We studied signal flow in the isolated rabbit retina with a multielectrode...

  19. Four of the six Drosophila rhodopsin-expressing photoreceptors can mediate circadian entrainment in low light.

    Science.gov (United States)

    Saint-Charles, Alexandra; Michard-Vanhée, Christine; Alejevski, Faredin; Chélot, Elisabeth; Boivin, Antoine; Rouyer, François

    2016-10-01

    Light is the major stimulus for the synchronization of circadian clocks with day-night cycles. The light-driven entrainment of the clock that controls rest-activity rhythms in Drosophila relies on different photoreceptive molecules. Cryptochrome (CRY) is expressed in most brain clock neurons, whereas six different rhodopsins (RH) are present in the light-sensing organs. The compound eye includes outer photoreceptors that express RH1 and inner photoreceptors that each express one of the four rhodopsins RH3-RH6. RH6 is also expressed in the extraretinal Hofbauer-Buchner eyelet, whereas RH2 is only found in the ocelli. In low light, the synchronization of behavioral rhythms relies on either CRY or the canonical rhodopsin phototransduction pathway, which requires the phospholipase C-β encoded by norpA (no receptor potential A). We used norpA(P24) cry(02) double mutants that are circadianly blind in low light and restored NORPA function in each of the six types of photoreceptors, defined as expressing a particular rhodopsin. We first show that the NORPA pathway is less efficient than CRY for synchronizing rest-activity rhythms with delayed light-dark cycles but is important for proper phasing, whereas the two light-sensing pathways can mediate efficient adjustments to phase advances. Four of the six rhodopsin-expressing photoreceptors can mediate circadian entrainment, and all are more efficient for advancing than for delaying the behavioral clock. In contrast, neither RH5-expressing retinal photoreceptors nor RH2-expressing ocellar photoreceptors are sufficient to mediate synchronization through the NORPA pathway. Our results thus reveal different contributions of rhodopsin-expressing photoreceptors and suggest the existence of several circuits for rhodopsin-dependent circadian entrainment. J. Comp. Neurol. 524:2828-2844, 2016. © 2016 Wiley Periodicals, Inc. PMID:26972685

  20. Influenza vaccines for avian species.

    Science.gov (United States)

    Kapczynski, Darrell R; Swayne, David E

    2009-01-01

    Beginning in Southeast Asia in 2003, a multinational epizootic outbreak of H5N1 highly pathogenic avian influenza (HPAI) was identified in commercial poultry and wild bird species. This lineage, originally identified in Southern China in 1996 and then Hong Kong in 1997, caused severe morbidity and mortality in many bird species, was responsible for considerable economic losses via trade restrictions, and crossed species barriers (including its recovery from human cases). To date, these H5N1 HPAI viruses have been isolated in European, Middle Eastern, and African countries, and are considered endemic in many areas where regulatory control and different production sectors face substantial hurdles in controlling the spread of this disease. While control of avian influenza (AI) virus infections in wild bird populations may not be feasible at this point, control and eradiation of AI from commercial, semicommercial, zoo, pet, and village/backyard birds will be critical to preventing events that could lead to the emergence of epizootic influenza virus. Efficacious vaccines can help reduce disease, viral shedding, and transmission to susceptible cohorts. However, only when vaccines are used in a comprehensive program including biosecurity, education, culling, diagnostics and surveillance can control and eradication be considered achievable goals. In humans, protection against influenza is provided by vaccines that are chosen based on molecular, epidemiologic, and antigenic data. In poultry and other birds, AI vaccines are produced against a specific hemagglutinin subtype of AI, and use is decided by government and state agricultural authorities based on risk and economic considerations, including the potential for trade restrictions. In the current H5N1 HPAI epizootic, vaccines have been used in a variety of avian species as a part of an overall control program to aid in disease management and control. PMID:19768403

  1. Cone penetrometer demonstration standard startup review checklist

    International Nuclear Information System (INIS)

    Startup readiness for the Cone Penetrometer Demonstration in AX Tank Farm will be verified through the application of a Standard Startup Review Checklist. This is a listing of those items essential to demonstrating readiness to start the Cone Penetrometer Demonstration in AX Tank Farm

  2. Cone Penetrometer N Factor Determination Testing Results

    Energy Technology Data Exchange (ETDEWEB)

    Follett, Jordan R.

    2014-03-05

    This document contains the results of testing activities to determine the empirical 'N Factor' for the cone penetrometer in kaolin clay simulant. The N Factor is used to releate resistance measurements taken with the cone penetrometer to shear strength.

  3. Regeneration of Cone Outer Segments Induced by CNTF

    OpenAIRE

    Wen, Rong; Tao, Weng; Luo, Lingyu; Huang, Deqiang; Kauper, Konrad; Stabila, Paul; LaVail, Matthew M.; Laties, Alan M.; Li, Yiwen

    2012-01-01

    Secondary cone degeneration in the transgenic rats carrying the S334ter rhodopsin mutation (S334ter-3 rats) starts at the peak of rod degeneration (PD12) and progresses with age. An early sign of cone degeneration is the loss of cone outer segments (COS) distributed in many small patches throughout the retina. Cone cell death occurs about 2 months later. When treated with CNTF (ciliary neurotrophic factor), impaired cones regenerate COS. Sustained delivery of CNTF prevents cones from degenera...

  4. Avian Influenza Virus: The Threat of A Pandemic

    OpenAIRE

    Shih-Cheng Chang; Yi-Ying Cheng; Shin-Ru Shih

    2006-01-01

    The 1918 influenza A virus pandemic caused a death toll of 40~50 million. Currently,because of the widespread dissemination of the avian influenza virus (H5N1), there is a highrisk of another pandemic. Avian species are the natural hosts for numerous subtypes ofinfluenza A viruses; however, the highly pathogenic avian influenza virus (HPAI) is not onlyextremely lethal to domestic avian species but also can infect humans and cause death. Thisreview discusses why the avian influenza virus is co...

  5. Double Dirac cones in phononic crystals

    KAUST Repository

    Li, Yan

    2014-07-07

    A double Dirac cone is realized at the center of the Brillouin zone of a two-dimensional phononic crystal (PC) consisting of a triangular array of core-shell-structure cylinders in water. The double Dirac cone is induced by the accidental degeneracy of two double-degenerate Bloch states. Using a perturbation method, we demonstrate that the double Dirac cone is composed of two identical and overlapping Dirac cones whose linear slopes can also be accurately predicted from the method. Because the double Dirac cone occurs at a relatively low frequency, a slab of the PC can be mapped onto a slab of zero refractive index material by using a standard retrieval method. Total transmission without phase change and energy tunneling at the double Dirac point frequency are unambiguously demonstrated by two examples. Potential applications can be expected in diverse fields such as acoustic wave manipulations and energy flow control.

  6. A role for prenylated rab acceptor 1 in vertebrate photoreceptor development

    Directory of Open Access Journals (Sweden)

    Dickison Virginia M

    2012-12-01

    Full Text Available Abstract Background The rd1 mouse retina is a well-studied model of retinal degeneration where rod photoreceptors undergo cell death beginning at postnatal day (P 10 until P21. This period coincides with photoreceptor terminal differentiation in a normal retina. We have used the rd1 retina as a model to investigate early molecular defects in developing rod photoreceptors prior to the onset of degeneration. Results Using a microarray approach, we performed gene profiling comparing rd1 and wild type (wt retinas at four time points starting at P2, prior to any obvious biochemical or morphological differences, and concluding at P8, prior to the initiation of cell death. Of the 143 identified differentially expressed genes, we focused on Rab acceptor 1 (Rabac1, which codes for the protein Prenylated rab acceptor 1 (PRA1 and plays an important role in vesicular trafficking. Quantitative RT-PCR analysis confirmed reduced expression of PRA1 in rd1 retina at all time points examined. Immunohistochemical observation showed that PRA1-like immunoreactivity (LIR co-localized with the cis-Golgi marker GM-130 in the photoreceptor as the Golgi translocated from the perikarya to the inner segment during photoreceptor differentiation in wt retinas. Diffuse PRA1-LIR, distinct from the Golgi marker, was seen in the distal inner segment of wt photoreceptors starting at P8. Both plexiform layers contained PRA1 positive punctae independent of GM-130 staining during postnatal development. In the inner retina, PRA1-LIR also colocalized with the Golgi marker in the perinuclear region of most cells. A similar pattern was seen in the rd1 mouse inner retina. However, punctate and significantly reduced PRA1-LIR was present throughout the developing rd1 inner segment, consistent with delayed photoreceptor development and abnormalities in Golgi sorting and vesicular trafficking. Conclusions We have identified genes that are differentially regulated in the rd1 retina at early

  7. Avian botulism and avian chlamydiosis in wild water birds, Benton Lake National Wildlife Refuge, Montana, USA

    Science.gov (United States)

    Docherty, Douglas E.; Franson, J. Christian; Brannian, Roger E.; Long, Renee R.; Radi, Craig A.; Krueger, David; Johnson, Robert F.

    2012-01-01

    In 1999, the U.S. Geological Survey (USGS) National Wildlife Health Center, Madison, Wisconsin, conducted a diagnostic investigation into a water bird mortality event involving intoxication with avian botulism type C and infection with avian chlamydiosis at the Benton Lake National Wildlife Refuge in Montana, USA. Of 24 carcasses necropsied, 11 had lesions consistent with avian chlamydiosis, including two that tested positive for infectious Chlamydophila psittaci, and 12 were positive for avian botulism type C. One bird tested positive for both avian botulism type C and C. psittaci. Of 61 apparently healthy water birds sampled and released, 13 had serologic evidence of C. psittaci infection and 7 were, at the time of capture, shedding infectious C. psittaci via the cloacal or oropharyngeal route. Since more routinely diagnosed disease conditions may mask avian chlamydiosis, these findings support the need for a comprehensive diagnostic investigation when determining the cause of a wildlife mortality event.

  8. Knockout of RP2 decreases GRK1 and rod transducin subunits and leads to photoreceptor degeneration in zebrafish.

    Science.gov (United States)

    Liu, Fei; Chen, Jiaxiang; Yu, Shanshan; Raghupathy, Rakesh Kotapati; Liu, Xiliang; Qin, Yayun; Li, Chang; Huang, Mi; Liao, Shengjie; Wang, Jiuxiang; Zou, Jian; Shu, Xinhua; Tang, Zhaohui; Liu, Mugen

    2015-08-15

    Retinitis pigmentosa (RP) affects about 1.8 million individuals worldwide. X-linked retinitis pigmentosa (XLRP) is one of the most severe forms of RP. Nearly 85% of XLRP cases are caused by mutations in the X-linked retinitis pigmentosa 2 (RP2) and RPGR. RP2 has been considered to be a GTPase activator protein for ARL3 and to play a role in the traffic of ciliary proteins. The mechanism of how RP2 mutations cause RP is still unclear. In this study, we generated an RP2 knockout zebrafish line using transcription activator-like effector nuclease technology. Progressive retinal degeneration could be observed in the mutant zebrafish. The degeneration of rods' outer segments (OSs) is predominant, followed by the degeneration of cones' OS. These phenotypes are similar to the characteristics of RP2 patients, and also partly consistent with the phenotypes of RP2 knockout mice and morpholino-mediated RP2 knockdown zebrafish. For the first time, we found RP2 deletion leads to decreased protein levels and abnormal retinal localizations of GRK1 and rod transducin subunits (GNAT1 and GNB1) in zebrafish. Furthermore, the distribution of the total farnesylated proteins in zebrafish retina is also affected by RP2 ablation. These molecular alterations observed in the RP2 knockout zebrafish might probably be responsible for the gradual loss of the photoreceptors' OSs. Our work identified the progression of retinal degeneration in RP2 knockout zebrafish, provided a foundation for revealing the pathogenesis of RP caused by RP2 mutations, and would help to develop potential therapeutics against RP in further studies. PMID:26034134

  9. Use of Hydrogen as a Novel Therapeutic Strategy Against Photoreceptor Degeneration in Retinitis Pigmentosa Patients

    Science.gov (United States)

    Tao, Ye; Geng, Lei; Wang, Liqiang; Xu, Weiwei; Qin, Limin; Peng, Guanghua; Huang, Yi Fei; Yang, Ji xue

    2016-01-01

    Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterized by progressive photoreceptor apoptosis. Reactive oxygen species (ROS) have been recognized as critical initiators of the photoreceptor apoptosis in RP. Photoreceptor survival in RP mutants will not only require the inhibition of effectors of apoptotic machinery, but also the elimination of the initiating upstream signals, such as ROS. These cytotoxic ROS should be neutralized by the antioxidant defense system, otherwise they would interact with the macromolecules essential for photoreceptor survival. Hydrogen is a promising gaseous agent that has come to the forefront of therapeutic research over the last few years. It has been verified that hydrogen is capable of neutralizing the cytotoxic ROS selectively, rectifying abnormities in the apoptotic cascades, and attenuating the related inflammatory response. Hydrogen is so mild that it does not disturb the metabolic oxidation-reduction reactions or disrupt the physiologic ROS involved in cell signaling. Based on these findings, we hypothesize that hydrogen might be an effective therapeutic agent to slow or prevent photoreceptor degeneration in RP retinas. It is a logical step to test hydrogen for therapeutic use in multiple RP animal models, and ultimately in human RP patients. PMID:26952558

  10. Photoreceptors in the rat retina are specifically vulnerable to both hypoxia and hyperoxia.

    Science.gov (United States)

    Wellard, John; Lee, Donald; Valter, Krisztina; Stone, Jonathan

    2005-01-01

    The current study aims to assess the vulnerability of photoreceptors in rat retina to variations in tissue oxygen levels. Young adult Sprague-Dawley rats were exposed to air with the concentration of oxygen set at 10% (hypoxia), 21% (room air, normoxia), and four levels of hyperoxia (45%, 65%, 70%, and 75%), for up to 3 weeks. Their retinas were then examined for cell death, using the TUNEL technique. Hypoxia (10% oxygen) for 2 weeks caused a limited but significant rise in the frequency of TUNEL+ (dying) cells in the retina, the great majority (>90%) being located in the outer nuclear layer (ONL). Hyperoxia also induced an increase in the frequency of TUNEL+ cells, again predominantly in the ONL. The increase rose with duration of exposure, up to 2 weeks. At 2 weeks exposure, the increase was limited yet significant at 45% oxygen, and maximal at 65%. Where the frequencies of TUNEL+ cells were high, it was evident that photoreceptor death was maximal in the midperipheral retina. The adult retina is vulnerable to maintained shifts in oxygen availability to the retina, both below and above normal. The vulnerability is specific to photoreceptors; other retinal neurons appeared resistant to the exposures tested. Shifts in retinal oxygen levels caused by variations in ambient light, by the persistence of light through the normally dark (night) half of the day-night cycle, or by depletion of the photoreceptor population, may contribute to photoreceptor death in the normal retina. PMID:16212707

  11. In vitro transdifferentiation of human peripheral blood mononuclear cells to photoreceptor-like cells.

    Science.gov (United States)

    Komuta, Yukari; Ishii, Toshiyuki; Kaneda, Makoto; Ueda, Yasuji; Miyamoto, Kiyoko; Toyoda, Masashi; Umezawa, Akihiro; Seko, Yuko

    2016-01-01

    Direct reprogramming is a promising, simple and low-cost approach to generate target cells from somatic cells without using induced pluripotent stem cells. Recently, peripheral blood mononuclear cells (PBMCs) have attracted considerable attention as a somatic cell source for reprogramming. As a cell source, PBMCs have an advantage over dermal fibroblasts with respect to the ease of collecting tissues. Based on our studies involving generation of photosensitive photoreceptor cells from human iris cells and human dermal fibroblasts by transduction of photoreceptor-related transcription factors via retrovirus vectors, we transduced these transcription factors into PBMCs via Sendai virus vectors. We found that retinal disease-related genes were efficiently detected in CRX-transduced cells, most of which are crucial to photoreceptor functions. In functional studies, a light-induced inward current was detected in some CRX-transduced cells. Moreover, by modification of the culture conditions including additional transduction of RAX1 and NEUROD1, we found a greater variety of retinal disease-related genes than that observed in CRX-transduced PBMCs. These data suggest that CRX acts as a master control gene for reprogramming PBMCs into photoreceptor-like cells and that our induced photoreceptor-like cells might contribute to individualized drug screening and disease modeling of inherited retinal degeneration. PMID:27170256

  12. Knockdown of ttc26 disrupts ciliogenesis of the photoreceptor cells and the pronephros in zebrafish.

    Science.gov (United States)

    Zhang, Qi; Liu, Qin; Austin, Chrissy; Drummond, Iain; Pierce, Eric A

    2012-08-01

    In our effort to understand genetic disorders of the photoreceptor cells of the retina, we have focused on intraflagellar transport in photoreceptor sensory cilia. From previous mouse proteomic data we identified a cilia protein Ttc26, orthologue of dyf-13 in Caenorhabditis elegans, as a target. We localized Ttc26 to the transition zone of photoreceptor and to the transition zone of cilia in cultured murine inner medullary collecting duct 3 (mIMCD3) renal cells. Knockdown of Ttc26 in mIMCD3 cells produced shortened and defective primary cilia, as revealed by immunofluorescence and scanning electron microscopy. To study Ttc26 function in sensory cilia in vivo, we utilized a zebrafish vertebrate model system. Morpholino knockdown of ttc26 in zebrafish embryos caused ciliary defects in the pronephric kidney at 27 h postfertilization and distension/dilation of pronephros at 5 d postfertilization (dpf). In the eyes, the outer segments of photoreceptor cells appeared shortened or absent, whereas cellular lamination appeared normal in retinas at 5 dpf. This suggests that loss of ttc26 function prevents normal ciliogenesis and differentiation in the photoreceptor cells, and that ttc26 is required for normal development and differentiation in retina and pronephros. Our studies support the importance of Ttc26 function in ciliogenesis and suggest that screening for TTC26 mutations in human ciliopathies is justified. PMID:22718903

  13. Photoreceptor effects on plant biomass, resource allocation, and metabolic state.

    Science.gov (United States)

    Yang, Deyue; Seaton, Daniel D; Krahmer, Johanna; Halliday, Karen J

    2016-07-01

    Plants sense the light environment through an ensemble of photoreceptors. Members of the phytochrome class of light receptors are known to play a critical role in seedling establishment, and are among the best-characterized plant signaling components. Phytochromes also regulate adult plant growth; however, our knowledge of this process is rather fragmented. This study demonstrates that phytochrome controls carbon allocation and biomass production in the developing plant. Phytochrome mutants have a reduced CO2 uptake, yet overaccumulate daytime sucrose and starch. This finding suggests that even though carbon fixation is impeded, the available carbon resources are not fully used for growth during the day. Supporting this notion, phytochrome depletion alters the proportion of day:night growth. In addition, phytochrome loss leads to sizeable reductions in overall growth, dry weight, total protein levels, and the expression of CELLULOSE SYNTHASE-LIKE genes. Because cellulose and protein are major constituents of plant biomass, our data point to an important role for phytochrome in regulating these fundamental components of plant productivity. We show that phytochrome loss impacts core metabolism, leading to elevated levels of tricarboxylic acid cycle intermediates, amino acids, sugar derivatives, and notably the stress metabolites proline and raffinose. Furthermore, the already growth-retarded phytochrome mutants are less responsive to growth-inhibiting abiotic stresses and have elevated expression of stress marker genes. This coordinated response appears to divert resources from energetically costly biomass production to improve resilience. In nature, this strategy may be activated in phytochrome-disabling, vegetation-dense habitats to enhance survival in potentially resource-limiting conditions. PMID:27330114

  14. Dopaminergic modulation of the caudal photoreceptor in crayfish.

    Science.gov (United States)

    Rodríguez-Sosa, Leonardo; Calderón-Rosete, Gabina; Calvillo, Minerva E; Guevara, Jorge; Flores, Gonzalo

    2011-06-01

    In our study we investigated the influence of dopamine (DA) on the caudal photoreceptor (CPR) in crayfish. Here we report the following: (a) the chromatographic determination of DA in the sixth abdominal ganglion (6th AG) shows a variation in the content during a 24-h cycle with the maximum value at dawn. (b) There are possibly dopaminergic neurons in the 6th AG with antityrosine hydroxylase antibodies. Immunopositive neurons (164) were located in the anterior and posterior regions of the 6th AG with the mean (± SE) diameter of their somata 23 ± 1 μm. In addition, there is immunopositive staining in axons, neuropilar fibers, and varicosities. (c) We also identified, using immunohistochemistry, 108 neurons in the sixth AG that contain dopamine D1-like receptors, with the mean (±SE) diameter of their somata 18 ± 1 μm. (d) We examined the exogenous action of DA on the electrical activity of the CPR in the isolated sixth AG by conventional extracellular-recording methods. This CPR displays spontaneous activity and phasic-tonic responses to light pulses. Topical application of dopamine to ganglia kept in the dark increased the spontaneous firing rate of the CPR, whereas the photoresponse of the CPR remained unchanged. The effect on the spontaneous activity is dose-dependent with an ED₅₀ of 33 μM, and is blocked by the dopamine D1-like antagonist SCH23390. These observations suggested that the DA is playing the role of a neurotransmitter or a neuromodulator of the CPR in the 6th AG in both species of crayfish, Procambarus clarkii and Cherax quadricarinatus. PMID:20936686

  15. Functional and topological diversity of LOV domain photoreceptors.

    Science.gov (United States)

    Glantz, Spencer T; Carpenter, Eric J; Melkonian, Michael; Gardner, Kevin H; Boyden, Edward S; Wong, Gane Ka-Shu; Chow, Brian Y

    2016-03-15

    Light-oxygen-voltage sensitive (LOV) flavoproteins are ubiquitous photoreceptors that mediate responses to environmental cues. Photosensory inputs are transduced into signaling outputs via structural rearrangements in sensor domains that consequently modulate the activity of an effector domain or multidomain clusters. Establishing the diversity in effector function and sensor-effector topology will inform what signaling mechanisms govern light-responsive behaviors across multiple kingdoms of life and how these signals are transduced. Here, we report the bioinformatics identification of over 6,700 candidate LOV domains (including over 4,000 previously unidentified sequences from plants and protists), and insights from their annotations for ontological function and structural arrangements. Motif analysis identified the sensors from ∼42 million ORFs, with strong statistical separation from other flavoproteins and non-LOV members of the structurally related Per-aryl hydrocarbon receptor nuclear translocator (ARNT)-Sim family. Conserved-domain analysis determined putative light-regulated function and multidomain topologies. We found that for certain effectors, sensor-effector linker length is discretized based on both phylogeny and the preservation of α-helical heptad repeats within an extended coiled-coil linker structure. This finding suggests that preserving sensor-effector orientation is a key determinant of linker length, in addition to ancestry, in LOV signaling structure-function. We found a surprisingly high prevalence of effectors with functions previously thought to be rare among LOV proteins, such as regulators of G protein signaling, and discovered several previously unidentified effectors, such as lipases. This work highlights the value of applying genomic and transcriptomic technologies to diverse organisms to capture the structural and functional variation in photosensory proteins that are vastly important in adaptation, photobiology, and optogenetics

  16. Functional and topological diversity of LOV domain photoreceptors

    Science.gov (United States)

    Glantz, Spencer T.; Carpenter, Eric J.; Melkonian, Michael; Boyden, Edward S.; Wong, Gane Ka-Shu; Chow, Brian Y.

    2016-01-01

    Light–oxygen–voltage sensitive (LOV) flavoproteins are ubiquitous photoreceptors that mediate responses to environmental cues. Photosensory inputs are transduced into signaling outputs via structural rearrangements in sensor domains that consequently modulate the activity of an effector domain or multidomain clusters. Establishing the diversity in effector function and sensor–effector topology will inform what signaling mechanisms govern light-responsive behaviors across multiple kingdoms of life and how these signals are transduced. Here, we report the bioinformatics identification of over 6,700 candidate LOV domains (including over 4,000 previously unidentified sequences from plants and protists), and insights from their annotations for ontological function and structural arrangements. Motif analysis identified the sensors from ∼42 million ORFs, with strong statistical separation from other flavoproteins and non-LOV members of the structurally related Per-aryl hydrocarbon receptor nuclear translocator (ARNT)-Sim family. Conserved-domain analysis determined putative light-regulated function and multidomain topologies. We found that for certain effectors, sensor–effector linker length is discretized based on both phylogeny and the preservation of α-helical heptad repeats within an extended coiled-coil linker structure. This finding suggests that preserving sensor–effector orientation is a key determinant of linker length, in addition to ancestry, in LOV signaling structure–function. We found a surprisingly high prevalence of effectors with functions previously thought to be rare among LOV proteins, such as regulators of G protein signaling, and discovered several previously unidentified effectors, such as lipases. This work highlights the value of applying genomic and transcriptomic technologies to diverse organisms to capture the structural and functional variation in photosensory proteins that are vastly important in adaptation, photobiology, and

  17. Presence of avian bornavirus RNA and anti-avian bornavirus antibodies in apparently healthy macaws.

    Science.gov (United States)

    De Kloet, Siwo R; Dorrestein, Gerry M

    2009-12-01

    Recently a novel avian bornavirus has been described that has been suggested to be the possible etiological agent for proventricular dilatation disease or macaw wasting disease. This article describes two macaws that shed avian bornaviral RNA sequences and demonstrated anti-avian bornavirus antibodies as revealed by reverse transcriptase polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and Western blot, yet are free of outward clinical signs of the disease. PMID:20095158

  18. Whirling skirts and rotating cones

    CERN Document Server

    Guven, Jemal; Müller, Martin Michael

    2013-01-01

    Steady, dihedrally symmetric patterns with sharp peaks may be observed on a spinning skirt, lagging behind the material flow of the fabric. These qualitative features are captured with a minimal model of traveling waves on an inextensible, flexible, generalized-conical sheet rotating about a fixed axis. Conservation laws are used to reduce the dynamics to a quadrature describing a particle in a three-parameter family of potentials. One parameter is associated with the stress in the sheet, the second is the Noether current associated with rotational invariance, and the third is a Rossby number which indicates the relative strength of Coriolis forces. Solutions are quantized by enforcing a topology appropriate to a skirt and a particular choice of dihedral symmetry. A perturbative analysis of nearly axisymmetric cones shows that Coriolis effects are essential in establishing skirt-like solutions. Fully non-linear solutions with three-fold symmetry are presented, which bear a suggestive resemblance to the observ...

  19. Avian influenza: an osteopathic component to treatment

    OpenAIRE

    Hruby, Raymond J; Hoffman, Keasha N

    2007-01-01

    Avian influenza is an infection caused by the H5N1 virus. The infection is highly contagious among birds, and only a few known cases of human avian influenza have been documented. However, healthcare experts around the world are concerned that mutation or genetic exchange with more commonly transmitted human influenza viruses could result in a pandemic of avian influenza. Their concern remains in spite of the fact that the first United States vaccine against the H5N1 virus was recently approv...

  20. Parafoveal retinal cone mosaic imaging in children with ultra-compact switchable SLO/OCT handheld probe (Conference Presentation)

    Science.gov (United States)

    LaRocca, Francesco; Nankivil, Derek; DuBose, Theodore B.; Toth, Cynthia A.; Farsiu, Sina; Izatt, Joseph A.

    2016-03-01

    In vivo photoreceptor imaging has enhanced the way vision scientists and ophthalmologists understand the retinal structure, function, and etiology of numerous retinal pathologies. However, the complexity and large footprint of current systems capable of resolving photoreceptors has limited imaging to patients who are able to sit in an upright position and fixate for several minutes. Unfortunately, this excludes an important fraction of patients including bedridden patients, small children, and infants. Here, we show that our dual-modality, high-resolution handheld probe with a weight of only 94 g is capable of visualizing photoreceptors in supine children. Our device utilizes a microelectromechanical systems (MEMS) scanner and a novel telescope design to achieve over an order of magnitude reduction in size compared to similar systems. The probe has a 7° field of view and a lateral resolution of 8 µm. The optical coherence tomography (OCT) system has an axial resolution of 7 µm and a sensitivity of 101 dB. High definition scanning laser ophthalmoscopy (SLO) and OCT images were acquired from children ranging from 14 months to 12 years of age with and without pathology during examination under anesthesia in the operating room. Parafoveal cone imaging was shown using the SLO arm of this device without adaptive optics using a 3° FOV for the first time in children under 4 years old. This work lays the foundation for pediatric research, which will improve understanding of retinal development, maldevelopment and early onset of diseases at the cellular level during the beginning stages of human growth.

  1. Depth-resolved rhodopsin molecular contrast imaging for functional assessment of photoreceptors

    Science.gov (United States)

    Liu, Tan; Wen, Rong; Lam, Byron L.; Puliafito, Carmen A.; Jiao, Shuliang

    2015-09-01

    Rhodopsin, the light-sensing molecule in the outer segments of rod photoreceptors, is responsible for converting light into neuronal signals in a process known as phototransduction. Rhodopsin is thus a functional biomarker for rod photoreceptors. Here we report a novel technology based on visible-light optical coherence tomography (VIS-OCT) for in vivo molecular imaging of rhodopsin. The depth resolution of OCT allows the visualization of the location where the change of optical absorption occurs and provides a potentially accurate assessment of rhodopsin content by segmentation of the image at the location. Rhodopsin OCT can be used to quantitatively image rhodopsin distribution and thus assess the distribution of functional rod photoreceptors in the retina. Rhodopsin OCT can bring significant impact into ophthalmic clinics by providing a tool for the diagnosis and severity assessment of a variety of retinal conditions.

  2. Shaggy Photoreceptors with Subfoveal Fluid Associated with a Distant Choroidal Melanoma

    Directory of Open Access Journals (Sweden)

    Ann Q. Tran

    2015-01-01

    Full Text Available Purpose. To describe the enhanced depth imaging optical coherence tomography (EDI-OCT findings in a patient with an extra macula choroidal melanoma before and after treatment. Methods. Observational case report. Results. A 45 year-old Caucasian male patient was referred to retina clinic for management of choroidal melanoma. Examination revealed a nasal choroidal melanoma while EDI-OCT illustrated subfoveal fluid pocket with elongated shaggy photoreceptors distant and separate from the tumor. The patient was treated with plaque brachytherapy and intravitreal bevacizumab. One week after plaque removal, there was a dramatic reduction in the shaggy photoreceptors. Conclusion. Choroidal melanomas have effects that are not localized to the area of the tumor. This loculated pocket of subretinal fluid and coinciding changes to photoreceptor morphology may be related to global changes in choroidal function or release of tumor related cytokines.

  3. Discrete potential waves in the photoreceptors of a gastropod mollusc, Hermissenda crassicornis.

    Science.gov (United States)

    Takeda, T

    1982-01-01

    Intracellular recording of dark adapted photoreceptors of Hermissenda crassicornis (Opisthobranchia, Gastropoda, Mollusca) revealed the occurrence of depolarizing waves even after blockade of synaptic transmission and postsynaptic potentials by application of low Ca2+ and high Mg2+ solution. Dim illumination increased the frequency of depolarizing waves. These observations show that Hermissenda photoreceptors have discrete waves which have been demonstrated mainly in arthropod photoreceptors. An histogram of intervals between successive discrete waves under continuous dim illumination was exponential, which is characteristic of a Poisson process. Frequency of discrete waves increased linearly depending on numbers of incident photons to the eye. Comparison of probabilities of eliciting a response to brief dim flashes of various intensities to theoretical Poisson sum curves, together with statistical analysis, indicate that the absorption of single photon is sufficient to evoke a discrete wave. PMID:7101766

  4. Use of a local cone model to predict essential CSF light adaptation behavior used in the design of luminance quantization nonlinearities

    Science.gov (United States)

    Daly, Scott; Golestaneh, S. A.

    2015-03-01

    The human visual system's luminance nonlinearity ranges continuously from square root behavior in the very dark, gamma-like behavior in dim ambient, cube-root in office lighting, and logarithmic for daylight ranges. Early display quantization nonlinearities have been developed based on luminance bipartite JND data. More advanced approaches considered spatial frequency behavior, and used the Barten light-adaptive Contrast Sensitivity Function (CSF) modelled across a range of light adaptation to determine the luminance nonlinearity (e.g., DICOM, referred to as a GSDF {grayscale display function}). A recent approach for a GSDF, also referred to as an electrical-to-optical transfer function (EOTF), using that light-adaptive CSF model improves on this by tracking the CSF for the most sensitive spatial frequency, which changes with adaptation level. We explored the cone photoreceptor's contribution to the behavior of this maximum sensitivity of the CSF as a function of light adaptation, despite the CSF's frequency variations and that the cone's nonlinearity is a point-process. We found that parameters of a local cone model could fit the max sensitivity of the CSF model, across all frequencies, and are within the ranges of parameters commonly accepted for psychophysicallytuned cone models. Thus, a linking of the spatial frequency and luminance dimensions has been made for a key neural component. This provides a better theoretical foundation for the recently designed visual signal format using the aforementioned EOTF.

  5. Histochemical study of retinal photoreceptors development during pre- and postnatal period and their association with retinal pigment epithelium

    Directory of Open Access Journals (Sweden)

    Vahid Ebrahimi

    2014-07-01

    Conclusion: According to our findings, we suggest that the generation of the eye photoreceptors begins from pre- natal period and their final differentiations will continue to postnatal period. Glycoconjugates including (β-D-Gal [1–3]-D-GalNac and (β-D-Gal terminal sugars play a critical role in the pre- and postnatal development and differentiation of retinal photoreceptors.

  6. Circadian plasticity in photoreceptor cells controls visual coding efficiency in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Martin Barth

    Full Text Available In the fly Drosophila melanogaster, neuronal plasticity of synaptic terminals in the first optic neuropil, or lamina, depends on early visual experience within a critical period after eclosion. The current study revealed two additional and parallel mechanisms involved in this type of synaptic terminal plasticity. First, an endogenous circadian rhythm causes daily oscillations in the volume of photoreceptor cell terminals. Second, daily visual experience precisely modulates the circadian time course and amplitude of the volume oscillations that the photoreceptor-cell terminals undergo. Both mechanisms are separable in their molecular basis. We suggest that the described neuronal plasticity in Drosophila ensures continuous optimal performance of the visual system over the course of a 24 h-day. Moreover, the sensory system of Drosophila cannot only account for predictable, but also for acute, environmental changes. The volumetric changes in the synaptic terminals of photoreceptor cells are accompanied by circadian and light-induced changes of presynaptic ribbons as well as extensions of epithelial glial cells into the photoreceptor terminals, suggesting that the architecture of the lamina is altered by both visual exposure and the circadian clock. Clock-mutant analysis and the rescue of PER protein rhythmicity exclusively in all R1-6 cells revealed that photoreceptor-cell plasticity is autonomous and sufficient to control visual behavior. The strength of a visually guided behavior, the optomotor turning response, co-varies with synaptic-terminal volume oscillations of photoreceptor cells when elicited at low light levels. Our results show that behaviorally relevant adaptive processing of visual information is performed, in part, at the level of visual input level.

  7. Chuanshi Brand Tri-cone Roller Bit

    Institute of Scientific and Technical Information of China (English)

    Chen Xilong; Shen Zhenzhong; Yuan Xiaoyi

    1997-01-01

    @@ Compared with other types of bits, the tri-cone roller bit has the advantages of excellent comprehensive performance, low price, wide usage range. It is free of formation limits. The tri-cone roller bit accounts for 90% of the total bits in use. The Chengdu Mechanical Works, as a major manufacturer of petroleum mechanical products and one of the four major tri-cone roller bit factories in China,has produced 120 types of bits in seven series and 19 sizes since 1967. The bits manufactured by the factory are not only sold to the domestic oilfields, but also exported to Japan, Thailand, Indonesia, the Philippines and the Middle East.

  8. Cone penetrometer moisture probe acceptance test report

    International Nuclear Information System (INIS)

    This Acceptance Test Report (ATR) documents the results of WHC-SD-WM-ATP-146 (Prototype Cone Penetrometer Moisture Probe Acceptance Test Procedure) and WHC-SD-WM-ATP-145 (Cone Penetrometer Moisture Probe Acceptance Test Procedure). The master copy of WHC-SD-WM-ATP-145 can be found in Appendix A and the master copy of WHC-SD-WM-ATP-146 can be found in Appendix B. Also included with this report is a matrix showing design criteria of the cone penetrometer moisture probe and the verification method used (Appendix C)

  9. Multiple elliptic gamma functions associated to cones

    CERN Document Server

    Winding, Jacob

    2016-01-01

    We define generalizations of the multiple elliptic gamma functions and the multiple sine functions, associated to good rational cones. We explain how good cones are related to collections of $SL_r(\\mathbb{Z})$-elements and prove that the generalized multiple sine and multiple elliptic gamma functions enjoy infinite product representations and modular properties determined by the cone. This generalizes the modular properties of the elliptic gamma function studied by Felder and Varchenko, and the results about the usual multiple sine and elliptic gamma functions found by Narukawa.

  10. Complexified cones. Spectral gaps and variational principles

    CERN Document Server

    Dubois, Loïc

    2010-01-01

    We consider contractions of complexified real cones, as recently introduced by Rugh in [Rugh10]. Dubois [Dub09] gave optimal conditions to determine if a matrix contracts a canonical complex cone. First we generalize his results to the case of complex operators on a Banach space and give precise conditions for the contraction and an improved estimate of the size of the associated spectral gap. We then prove a variational formula for the leading eigenvalue similar to the Collatz-Wielandt formula for a real cone contraction. Morally, both cases boil down to the study of suitable collections of 2 by 2 matrices and their contraction properties on the Riemann sphere.

  11. 77 FR 34783 - Highly Pathogenic Avian Influenza

    Science.gov (United States)

    2012-06-12

    ... avian influenza (HPAI). On January 24, 2011, we published in the Federal Register (76 FR 4046-4056... Register on May 3, 2011 (76 FR 24793, Docket No. APHIS-2006-0074), we reopened the comment period for...

  12. Clipping the wings of avian influenza

    OpenAIRE

    2012-01-01

    Up to now, the threat of avian influenza has been lessened by effective animal husbandry methods. However, the public health community is trying to ensure enough measures are in place to prevent a possible pandemic. Jane Parry reports.

  13. Avian Habitat Data; Seward Peninsula, Alaska, 2012

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data product contains avian habitat data collected on the Seward Peninsula, Alaska, USA, during 21 May – 10 June 2012. We conducted replicated 10-min surveys...

  14. Montana 2006 Avian Influenza Surveillance Project Report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — During the summer of 2006, the U.S. Department of Agriculture (USDA) and the U.S. Fish and Wildlife Service (USFWS) initiated a nationwide avian influenza...

  15. Transcription factor NF-Y is involved in differentiation of R7 photoreceptor cell in Drosophila

    OpenAIRE

    Yasuhide Yoshioka; Luong Linh Ly; Masamitsu Yamaguchi

    2011-01-01

    Summary The CCAAT motif-binding factor NF-Y consists of three different subunits, NF-YA, NF-YB and NF-YC. Knockdown of Drosophila NF-YA (dNF-YA) in eye discs with GMR-GAL4 and UAS-dNF-YAIR resulted in a rough eye phenotype and monitoring of differentiation of photoreceptor cells by LacZ expression in seven up-LacZ and deadpan-lacZ enhancer trap lines revealed associated loss of R7 photoreceptor signals. In line with differentiation of R7 being regulated by the sevenless (sev) gene and the MAP...

  16. No evidence for a genetic blueprint: The case of the "complex" mammalian photoreceptor

    Directory of Open Access Journals (Sweden)

    G Kumaramanickavel

    2015-01-01

    Full Text Available Despite the intensity of the search for genes causing inherited retinal degenerations over the past 3 decades, of the approximately 200 disease genes identified to date, all appear to be ordinary housekeeping genes specifying proteins playing basic structural and functional roles in the mature photoreceptor cells. No genes or genetic elements have been identified which can be construed as having a specific morphogenic role, directing the development of the cytoarchitecture of any particular retinal cell. The evidence suggests that the cytoarchitecture of the retinal photoreceptors, although enormously complex, arises from the self-organization of the cells constituents without any regulation or direction from an external genetic blueprint.

  17. Oseltamivir in human avian influenza infection

    OpenAIRE

    Smith, James R.

    2010-01-01

    Avian influenza A viruses continue to cause disease outbreaks in humans, and extrapulmonary infection is characteristic. In vitro studies demonstrate the activity of oseltamivir against avian viruses of the H5, H7 and H9 subtypes. In animal models of lethal infection, oseltamivir treatment and prophylaxis limit viral replication and improve survival. Outcomes are influenced by the virulence of the viral strain, dosage regimen and treatment delay; it is also critical for the compound to act sy...

  18. Avian influenza: an emerging pandemic threat.

    Science.gov (United States)

    Jin, Xian Wen; Mossad, Sherif B

    2005-12-01

    While we are facing the threat of an emerging pandemic from the current avian flu outbreak in Asia, we have learned important traits of the virus responsible for the 1918 Spanish influenza pandemic that made it so deadly. By using stockpiled antiviral drugs effectively and developing an effective vaccine, we can be in a better position than ever to mitigate the global impact of an avian influenza pandemic. PMID:16392727

  19. Cell killing by avian leukosis viruses.

    OpenAIRE

    Weller, S K; Temin, H M

    1981-01-01

    Infection of chicken cells with a cytopathic avian leukosis virus resulted in the detachment of killed cells from the culture dish. The detached, dead cells contained more unintegrated viral DNA than the attached cells. These results confirm the hypothesis that cell killing after infection with a cytopathic avian leukosis virus is associated with accumulation of large amounts of unintegrated viral DNA. No accumulation of large amounts of integrated viral DNA was found in cells infected with c...

  20. Avian Circadian Organization: A Chorus of Clocks

    OpenAIRE

    Cassone, Vincent M.

    2013-01-01

    In birds, biological clock function pervades all aspects of biology, controlling daily changes in sleep: wake, visual function, song, migratory patterns and orientation, as well as seasonal patterns of reproduction, song and migration. The molecular bases for circadian clocks are highly conserved, and it is likely the avian molecular mechanisms are similar to those expressed in mammals, including humans. The central pacemakers in the avian pineal gland, retinae and SCN dynamically interact to...

  1. A review of avian probiotics.

    Science.gov (United States)

    Smith, Jeanne Marie

    2014-06-01

    Probiotics have been used in poultry for decades and have become common in the pet bird industry. Desirable characteristics of probiotic organisms are that they are nonpathogenic, have the ability to adhere to intestinal epithelial cells, have the ability to colonize and reproduce in the host, have the ability to be host-specific, survive transit through the gastrointestinal tract and exposure to stomach acid and bile, produce metabolites that inhibit or kill pathogenic bacteria, modulate gastrointestinal immune responses, and survive processing and storage. Purported benefits in birds are disease prevention and promotion of growth. Recommendations for use in avian species are for periodic use to replenish normal flora, use after antibiotic therapy to reestablish normal flora, and use during periods of stress to counter effects of immunosuppression. PMID:25115036

  2. Light-Cone Expansion of the Dirac Sea with Light Cone Integrals

    OpenAIRE

    Finster, Felix

    1997-01-01

    The Dirac sea is calculated in an expansion around the light cone. The method is to analyze the perturbation expansion for the Dirac sea in position space. This leads to integrals over expressions containing distributions which are singular on the light cone. We derive asymptotic formulas for these "light cone integrals" in terms of line integrals over the external potential and its partial derivatives. The calculations are based on the perturbation expansion for the Dirac sea in the preprint...

  3. Ecology and conservation biology of avian malaria

    Science.gov (United States)

    LaPointe, Dennis A.; Atkinson, Carter T.; Samuel, Michael D.

    2012-01-01

    Avian malaria is a worldwide mosquito-borne disease caused by Plasmodium parasites. These parasites occur in many avian species but primarily affect passerine birds that have not evolved with the parasite. Host pathogenicity, fitness, and population impacts are poorly understood. In contrast to continental species, introduced avian malaria poses a substantial threat to naive birds on Hawaii, the Galapagos, and other archipelagoes. In Hawaii, transmission is maintained by susceptible native birds, competence and abundance of mosquitoes, and a disease reservoir of chronically infected native birds. Although vector habitat and avian communities determine the geographic distribution of disease, climate drives transmission patterns ranging from continuous high infection in warm lowland forests, seasonal infection in midelevation forests, and disease-free refugia in cool high-elevation forests. Global warming is expected to increase the occurrence, distribution, and intensity of avian malaria across this elevational gradient and threaten high-elevation refugia, which is the key to survival of many susceptible Hawaiian birds. Increased temperatures may have already increased global avian malaria prevalence and contributed to an emergence of disease in New Zealand.

  4. Mach cones in space and laboratory dusty magnetoplasmas

    International Nuclear Information System (INIS)

    We present a rigorous theoretical investigation on the possibility for the formation of Mach cones in both space and laboratory dusty magnetoplasmas. We find the parametric regimes for which different types of Mach cones, such as dust acoustic Mach cones, dust magneto-acoustic Mach cones, oscillonic Mach cones, etc. are formed in space and laboratory dusty magnetoplasmas. We also identify the basic features of such different classes of Mach cones (viz. dust- acoustic, dust magneto-acoustic, oscillonic Mach cones, etc.), and clearly explain how they are relevant to space and laboratory dusty manetoplasmas. (author)

  5. Shatter Cones from the MEMIN Impact Experiments

    Science.gov (United States)

    Wilk, J.; Kenkmann, T.

    2015-09-01

    We recovered shatter cone fragments from the MEMIN cratering experiments in sandstone, quartzite and limestone blocks. We analyzed the conical to hyperboloid, curved and striated fracture surfaces with SEM, WLI and produced µm-accurate 3D models.

  6. Performance Analysis of Cone Detection Algorithms

    CERN Document Server

    Mariotti, Letizia

    2015-01-01

    Many algorithms have been proposed to help clinicians evaluate cone density and spacing, as these may be related to the onset of retinal diseases. However, there has been no rigorous comparison of the performance of these algorithms. In addition, the performance of such algorithms is typically determined by comparison with human observers. Here we propose a technique to simulate realistic images of the cone mosaic. We use the simulated images to test the performance of two popular cone detection algorithms and we introduce an algorithm which is used by astronomers to detect stars in astronomical images. We use Free Response Operating Characteristic (FROC) curves to evaluate and compare the performance of the three algorithms. This allows us to optimize the performance of each algorithm. We observe that performance is significantly enhanced by up-sampling the images. We investigate the effect of noise and image quality on cone mosaic parameters estimated using the different algorithms, finding that the estimat...

  7. Some inversion formulas for the cone transform

    Science.gov (United States)

    Terzioglu, Fatma

    2015-11-01

    Several novel imaging applications have lead recently to a variety of Radon type transforms, where integration is made over a family of conical surfaces. We call them cone transforms (in 2D they are also called V-line or broken ray transforms). Most prominently, they are present in the so called Compton camera imaging that arises in medical diagnostics, astronomy, and lately in homeland security applications. Several specific incarnations of the cone transform have been considered separately. In this paper, we address the most general (and overdetermined) cone transform, obtain integral relations between cone and Radon transforms in {{{R}}}n, and a variety of inversion formulas. In many applications (e.g., in homeland security), the signal to noise ratio is very low. So, if overdetermined data is collected (as in the case of Compton imaging), attempts to reduce the dimensionality might lead to essential elimination of the signal. Thus, our main concentration is on obtaining formulas involving overdetermined data.

  8. Castelnuovo-Mumford regularity and Gorensteinness of fiber cone

    OpenAIRE

    Jayanthan, A. V.; Nanduri, Ramakrishna

    2011-01-01

    In this article, we study the Castelnuovo-Mumford regularity and Gorenstein properties of the fiber cone. We obtain upper bounds for the Castelnuovo-Mumford regularity of the fiber cone and obtain sufficient conditions for the regularity of the fiber cone to be equal to that of the Rees algebra. We obtain a formula for the canonical module of the fiber cone and use it to study the Gorenstein property of the fiber cone.

  9. Design of a trichromatic cone array.

    Directory of Open Access Journals (Sweden)

    Patrick Garrigan

    2010-02-01

    Full Text Available Cones with peak sensitivity to light at long (L, medium (M and short (S wavelengths are unequal in number on the human retina: S cones are rare (<10% while increasing in fraction from center to periphery, and the L/M cone proportions are highly variable between individuals. What optical properties of the eye, and statistical properties of natural scenes, might drive this organization? We found that the spatial-chromatic structure of natural scenes was largely symmetric between the L, M and S sensitivity bands. Given this symmetry, short wavelength attenuation by ocular media gave L/M cones a modest signal-to-noise advantage, which was amplified, especially in the denser central retina, by long-wavelength accommodation of the lens. Meanwhile, total information represented by the cone mosaic remained relatively insensitive to L/M proportions. Thus, the observed cone array design along with a long-wavelength accommodated lens provides a selective advantage: it is maximally informative.

  10. Lifts of convex sets and cone factorizations

    CERN Document Server

    Gouveia, João; Thomas, Rekha

    2011-01-01

    In this paper we address the basic geometric question of when a given convex set is the image under a linear map of an affine slice of a given closed convex cone. Such a representation or 'lift' of the convex set is especially useful if the cone admits an efficient algorithm for linear optimization over its affine slices. We show that the existence of a lift of a convex set to a cone is equivalent to the existence of a factorization of an operator associated to the set and its polar via elements in the cone and its dual. This generalizes a theorem of Yannakakis that established a connection between polyhedral lifts of a polytope and nonnegative factorizations of its slack matrix. Symmetric lifts of convex sets can also be characterized similarly. When the cones live in a family, our results lead to the definition of the rank of a convex set with respect to this family. We present results about this rank in the context of cones of positive semidefinite matrices. Our methods provide new tools for understanding ...

  11. Using avian radar to examine relationships among avian activity, bird strikes, and meteorological factors

    Science.gov (United States)

    Coates, Peter S.; Casazza, Michael L.; Halstead, Brian J.; Fleskes, Joseph P.; Laughlin, James A.

    2011-01-01

    Radar systems designed to detect avian activity at airfields are useful in understanding factors that influence the risk of bird and aircraft collisions (bird strikes). We used an avian radar system to measure avian activity at Beale Air Force Base, California, USA, during 2008 and 2009. We conducted a 2-part analysis to examine relationships among avian activity, bird strikes, and meteorological and time-dependent factors. We found that avian activity around the airfield was greater at times when bird strikes occurred than on average using a permutation resampling technique. Second, we developed generalized linear mixed models of an avian activity index (AAI). Variation in AAI was first explained by seasons that were based on average migration dates of birds at the study area. We then modeled AAI by those seasons to further explain variation by meteorological factors and daily light levels within a 24-hour period. In general, avian activity increased with decreased temperature, wind, visibility, precipitation, and increased humidity and cloud cover. These effects differed by season. For example, during the spring bird migration period, most avian activity occurred before sunrise at twilight hours on clear days with low winds, whereas during fall migration, substantial activity occurred after sunrise, and birds generally were more active at lower temperatures. We report parameter estimates (i.e., constants and coefficients) averaged across models and a relatively simple calculation for safety officers and wildlife managers to predict AAI and the relative risk of bird strike based on time, date, and meteorological values. We validated model predictability and assessed model fit. These analyses will be useful for general inference of avian activity and risk assessment efforts. Further investigation and ongoing data collection will refine these inference models and improve our understanding of factors that influence avian activity, which is necessary to inform

  12. Effective delivery of recombinant proteins to rod photoreceptors via lipid nanovesicles

    Energy Technology Data Exchange (ETDEWEB)

    Asteriti, Sabrina [Dept. of Translational Research, University of Pisa, Pisa (Italy); Dal Cortivo, Giuditta [Dept. of Life Sciences and Reproduction, University of Verona, Strada Le Grazie 8, Verona (Italy); Pontelli, Valeria [Dept. of Neurological and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona (Italy); Cangiano, Lorenzo [Dept. of Translational Research, University of Pisa, Pisa (Italy); Buffelli, Mario, E-mail: mario.buffelli@univr.it [Dept. of Neurological and Movement Sciences, University of Verona, Strada Le Grazie 8, Verona (Italy); Center for Biomedical Computing, University of Verona, Strada le Grazie 8, 37134 Verona (Italy); Dell’Orco, Daniele, E-mail: daniele.dellorco@univr.it [Dept. of Life Sciences and Reproduction, University of Verona, Strada Le Grazie 8, Verona (Italy); Center for Biomedical Computing, University of Verona, Strada le Grazie 8, 37134 Verona (Italy)

    2015-06-12

    The potential of liposomes to deliver functional proteins in retinal photoreceptors and modulate their physiological response was investigated by two experimental approaches. First, we treated isolated mouse retinas with liposomes encapsulating either recoverin, an important endogenous protein operating in visual phototransduction, or antibodies against recoverin. We then intravitrally injected in vivo liposomes encapsulating either rhodamin B or recoverin and we investigated the distribution in retina sections by confocal microscopy. The content of liposomes was found to be released in higher amount in the photoreceptor layer than in the other regions of the retina and the functional effects of the release were in line with the current model of phototransduction. Our study sets the basis for quantitative investigations aimed at assessing the potential of intraocular protein delivery via biocompatible nanovesicles, with promising implications for the treatment of retinal diseases affecting the photoreceptor layer. - Highlights: • Recombinant proteins encapsulated in nano-sized liposomes injected intravitreally reach retinal photoreceptors. • The phototransduction cascade in rods is modulated by the liposome content. • Mathematical modeling predicts the alteration of the photoresponses following liposome fusion.

  13. Xbp1-Independent Ire1 Signaling Is Required for Photoreceptor Differentiation and Rhabdomere Morphogenesis in Drosophila

    Directory of Open Access Journals (Sweden)

    Dina S. Coelho

    2013-11-01

    Full Text Available The unfolded protein response (UPR is composed by homeostatic signaling pathways that are activated by excessive protein misfolding in the endoplasmic reticulum. Ire1 signaling is an important mediator of the UPR, leading to the activation of the transcription factor Xbp1. Here, we show that Drosophila Ire1 mutant photoreceptors have defects in the delivery of rhodopsin-1 to the rhabdomere and in the secretion of Spacemaker/Eyes Shut into the interrhabdomeral space. However, these defects are not observed in Xbp1 mutant photoreceptors. Ire1 mutant retinas have higher mRNA levels for targets of regulated Ire1-dependent decay (RIDD, including for the fatty acid transport protein (fatp. Importantly, the downregulation of fatp by RNAi rescues the rhodopsin-1 delivery defects observed in Ire1 mutant photoreceptors. Our results show that the role of Ire1 during photoreceptor differentiation is independent of Xbp1 function and demonstrate the physiological relevance of the RIDD mechanism in this specific paradigm.

  14. Rod photoreceptors express GPR55 in the adult vervet monkey retina

    DEFF Research Database (Denmark)

    Bouskila, Joseph; Javadi, Pasha; Casanova, Christian;

    2013-01-01

    components (Müller cells). The aim of this study was to determine the expression pattern of GPR55 in the monkey retina by using confocal microscopy. Our results show that GPR55 is strictly localized in the photoreceptor layer of the extrafoveal portion of the retina. Co-immunolabeling of GPR55 with rhodopsin...

  15. Impaired Mitochondrial Energy Production Causes Light-Induced Photoreceptor Degeneration Independent of Oxidative Stress.

    Science.gov (United States)

    Jaiswal, Manish; Haelterman, Nele A; Sandoval, Hector; Xiong, Bo; Donti, Taraka; Kalsotra, Auinash; Yamamoto, Shinya; Cooper, Thomas A; Graham, Brett H; Bellen, Hugo J

    2015-07-01

    Two insults often underlie a variety of eye diseases including glaucoma, optic atrophy, and retinal degeneration--defects in mitochondrial function and aberrant Rhodopsin trafficking. Although mitochondrial defects are often associated with oxidative stress, they have not been linked to Rhodopsin trafficking. In an unbiased forward genetic screen designed to isolate mutations that cause photoreceptor degeneration, we identified mutations in a nuclear-encoded mitochondrial gene, ppr, a homolog of human LRPPRC. We found that ppr is required for protection against light-induced degeneration. Its function is essential to maintain membrane depolarization of the photoreceptors upon repetitive light exposure, and an impaired phototransduction cascade in ppr mutants results in excessive Rhodopsin1 endocytosis. Moreover, loss of ppr results in a reduction in mitochondrial RNAs, reduced electron transport chain activity, and reduced ATP levels. Oxidative stress, however, is not induced. We propose that the reduced ATP level in ppr mutants underlies the phototransduction defect, leading to increased Rhodopsin1 endocytosis during light exposure, causing photoreceptor degeneration independent of oxidative stress. This hypothesis is bolstered by characterization of two other genes isolated in the screen, pyruvate dehydrogenase and citrate synthase. Their loss also causes a light-induced degeneration, excessive Rhodopsin1 endocytosis and reduced ATP without concurrent oxidative stress, unlike many other mutations in mitochondrial genes that are associated with elevated oxidative stress and light-independent photoreceptor demise. PMID:26176594

  16. Geranylgeranylacetone Suppresses N-Methyl-N-nitrosourea-Induced Photoreceptor Cell Loss in Mice.

    Science.gov (United States)

    Koriyama, Yoshiki; Ogai, Kazuhiro; Sugitani, Kayo; Hisano, Suguru; Kato, Satoru

    2016-01-01

    Retinitis pigmentosa is a disease characterized by the loss of photoreceptor cells. The N-methyl-N-nitrosourea (MNU)-induced retinal degeneration model is widely used to study the mechanism of these retinal degenerative disorders because of its selective photoreceptor cell death. As for the cell death mechanism of MNU, calcium-calpain activation and lipid peroxidation processes are involved in the initiation of this cell death. Although such molecular mechanisms of the MNU-induced cell death have been described, the total image of the cell death is still obscure. Heat shock protein 70 (HSP70) has been shown to function as a chaperon molecule to protect cells against environmental and physiological stresses. In this study, we investigated the effect of geranylgeranylacetone (GGA), an accylic polyisoprenoid, on MNU-induced photoreceptor cell loss. HSP70 induction by GGA was effective against MNU-induced photoreceptor cell loss as a result of its ability to prevent HSP70 degradation. The data indicate that GGA may help to suppress the onset and progression of retinitis pigmentosa. PMID:26427417

  17. Melanopsin-expressing amphioxus photoreceptors transduce light via a phospholipase C signaling cascade.

    Directory of Open Access Journals (Sweden)

    Juan Manuel Angueyra

    Full Text Available Melanopsin, the receptor molecule that underlies light sensitivity in mammalian 'circadian' receptors, is homologous to invertebrate rhodopsins and has been proposed to operate via a similar signaling pathway. Its downstream effectors, however, remain elusive. Melanopsin also expresses in two distinct light-sensitive cell types in the neural tube of amphioxus. This organism is the most basal extant chordate and can help outline the evolutionary history of different photoreceptor lineages and their transduction mechanisms; moreover, isolated amphioxus photoreceptors offer unique advantages, because they are unambiguously identifiable and amenable to single-cell physiological assays. In the present study whole-cell patch clamp recording, pharmacological manipulations, and immunodetection were utilized to investigate light transduction in amphioxus photoreceptors. A G(q was identified and selectively localized to the photosensitive microvillar membrane, while the pivotal role of phospholipase C was established pharmacologically. The photocurrent was profoundly depressed by IP₃ receptor antagonists, highlighting the importance of IP₃ receptors in light signaling. By contrast, surrogates of diacylglycerol (DAG, as well as poly-unsaturated fatty acids failed to activate a membrane conductance or to alter the light response. The results strengthen the notion that calcium released from the ER via IP₃-sensitive channels may fulfill a key role in conveying--directly or indirectly--the melanopsin-initiated light signal to the photoconductance; moreover, they challenge the dogma that microvillar photoreceptors and phoshoinositide-based light transduction are a prerogative of invertebrate eyes.

  18. Effective delivery of recombinant proteins to rod photoreceptors via lipid nanovesicles

    International Nuclear Information System (INIS)

    The potential of liposomes to deliver functional proteins in retinal photoreceptors and modulate their physiological response was investigated by two experimental approaches. First, we treated isolated mouse retinas with liposomes encapsulating either recoverin, an important endogenous protein operating in visual phototransduction, or antibodies against recoverin. We then intravitrally injected in vivo liposomes encapsulating either rhodamin B or recoverin and we investigated the distribution in retina sections by confocal microscopy. The content of liposomes was found to be released in higher amount in the photoreceptor layer than in the other regions of the retina and the functional effects of the release were in line with the current model of phototransduction. Our study sets the basis for quantitative investigations aimed at assessing the potential of intraocular protein delivery via biocompatible nanovesicles, with promising implications for the treatment of retinal diseases affecting the photoreceptor layer. - Highlights: • Recombinant proteins encapsulated in nano-sized liposomes injected intravitreally reach retinal photoreceptors. • The phototransduction cascade in rods is modulated by the liposome content. • Mathematical modeling predicts the alteration of the photoresponses following liposome fusion

  19. Predicted molecular signaling guiding photoreceptor cell migration following transplantation into damaged retina

    Science.gov (United States)

    Unachukwu, Uchenna John; Warren, Alice; Li, Ze; Mishra, Shawn; Zhou, Jing; Sauane, Moira; Lim, Hyungsik; Vazquez, Maribel; Redenti, Stephen

    2016-03-01

    To replace photoreceptors lost to disease or trauma and restore vision, laboratories around the world are investigating photoreceptor replacement strategies using subretinal transplantation of photoreceptor precursor cells (PPCs) and retinal progenitor cells (RPCs). Significant obstacles to advancement of photoreceptor cell-replacement include low migration rates of transplanted cells into host retina and an absence of data describing chemotactic signaling guiding migration of transplanted cells in the damaged retinal microenvironment. To elucidate chemotactic signaling guiding transplanted cell migration, bioinformatics modeling of PPC transplantation into light-damaged retina was performed. The bioinformatics modeling analyzed whole-genome expression data and matched PPC chemotactic cell-surface receptors to cognate ligands expressed in the light-damaged retinal microenvironment. A library of significantly predicted chemotactic ligand-receptor pairs, as well as downstream signaling networks was generated. PPC and RPC migration in microfluidic ligand gradients were analyzed using a highly predicted ligand-receptor pair, SDF-1α - CXCR4, and both PPCs and RPCs exhibited significant chemotaxis. This work present a systems level model and begins to elucidate molecular mechanisms involved in PPC and RPC migration within the damaged retinal microenvironment.

  20. Exploring RPE as a source of photoreceptors: assessing cellular differentiation in vivo

    Science.gov (United States)

    To evaluate neuroD–induced RPE transdifferentiation into photoreceptor cells in the subretinal space, RPE cells were dissociated, cultured, and guided to transdifferentiate by infecting them with retrovirus RCAS–neuroD, or RCAS–GFP as a control. The cells were then harvested and microinjected into t...

  1. Avian Influenza A (H7N9) Virus

    Science.gov (United States)

    ... Research Making a Candidate Vaccine Virus Related Links Influenza Types Seasonal Avian Swine Variant Pandemic Other Get ... Submit What's this? Submit Button Past Newsletters Avian Influenza A (H7N9) Virus Language: English Español Recommend ...

  2. Avian Point Count Locations - Dahomey NWR 2007-2008

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Map depicts locations of avian point counts conducted on Dahomey in 2007 and 2008. Actual point count data are contained in the avian knowledge network database

  3. Radioimmunological comparison of the DNA polymerases of avian retroviruses.

    OpenAIRE

    Bauer, G.; Temin, H M

    1980-01-01

    125I-labeled DNA polymerases of avian myeloblastosis virus and spleen necrosis virus were used in a radioimmunological characterization of avian retrovirus DNA polymerases. It was shown that avian leukosis virus and reticuloendotheliosis virus DNA polymerases do not cross-react in radioimmunoassays. Within the avian leukosis virus species, species-specific and type-specific antigenic determinants of the DNA polymerase were defined. The previous finding of genus-specific antigenic determinants...

  4. Otx2 gene deletion in adult mouse retina induces rapid RPE dystrophy and slow photoreceptor degeneration.

    Directory of Open Access Journals (Sweden)

    Francis Béby

    Full Text Available BACKGROUND: Many developmental genes are still active in specific tissues after development is completed. This is the case for the homeobox gene Otx2, an essential actor of forebrain and head development. In adult mouse, Otx2 is strongly expressed in the retina. Mutations of this gene in humans have been linked to severe ocular malformation and retinal diseases. It is, therefore, important to explore its post-developmental functions. In the mature retina, Otx2 is expressed in three cell types: bipolar and photoreceptor cells that belong to the neural retina and retinal pigment epithelium (RPE, a neighbour structure that forms a tightly interdependent functional unit together with photoreceptor cells. METHODOLOGY/PRINCIPAL FINDINGS: Conditional self-knockout was used to address the late functions of Otx2 gene in adult mice. This strategy is based on the combination of a knock-in CreERT2 allele and a floxed allele at the Otx2 locus. Time-controlled injection of tamoxifen activates the recombinase only in Otx2 expressing cells, resulting in selective ablation of the gene in its entire domain of expression. In the adult retina, loss of Otx2 protein causes slow degeneration of photoreceptor cells. By contrast, dramatic changes of RPE activity rapidly occur, which may represent a primary cause of photoreceptor disease. CONCLUSIONS: Our novel mouse model uncovers new Otx2 functions in adult retina. We show that this transcription factor is necessary for long-term maintenance of photoreceptors, likely through the control of specific activities of the RPE.

  5. Proceedings of National Avian-Wind Power Planning Meeting IV

    Energy Technology Data Exchange (ETDEWEB)

    NWCC Avian Subcommittee

    2001-05-01

    OAK-B135 The purpose of the fourth meeting was to (1) share research and update research conducted on avian wind interactions (2) identify questions and issues related to the research results, (3) develop conclusions about some avian/wind power issues, and (4) identify questions and issues for future avian research.

  6. 9 CFR 113.325 - Avian Encephalomyelitis Vaccine.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Avian Encephalomyelitis Vaccine. 113... REQUIREMENTS Live Virus Vaccines § 113.325 Avian Encephalomyelitis Vaccine. Avian Encephalomyelitis Vaccine... vaccine production. All serials shall be prepared from the first through the fifth passage from the...

  7. N=8 supergravity on the light cone

    International Nuclear Information System (INIS)

    We construct the generating functional for the light-cone superfield amplitudes in a chiral momentum superspace. It generates the n-point particle amplitudes which on shell are equivalent to the covariant ones. Based on the action depending on the unconstrained light-cone chiral scalar superfield, this functional provides a regular d=4 quantum field theory path integral derivation of the Nair-type amplitude constructions. By performing a Fourier transform into the light-cone chiral coordinate superspace we find that the quantum corrections to the superfield amplitudes with n legs are nonlocal in transverse directions for the diagrams with the number of loops smaller than at least n+3. This suggests the reason why UV infinities, which are proportional to local vertices, cannot appear at least before 7 loops in the light-cone supergraph computations. Using the E7(7) symmetry we argue that the light-cone supergraphs predict all-loop finiteness of d=4 N=8 supergravity.

  8. Immunology of avian influenza virus: a review.

    Science.gov (United States)

    Suarez, D L; Schultz-Cherry, S

    2000-01-01

    Avian influenza virus can cause serious disease in a wide variety of birds and mammals, but its natural host range is in wild ducks, gulls, and shorebirds. Infections in poultry can be inapparent or cause respiratory disease, decreases in production, or a rapidly fatal systemic disease known as highly pathogenic avian influenza (HPAI). For the protection of poultry, neutralizing antibody to the hemagglutinin and neuraminidase proteins provide the primary protection against disease. A variety of vaccines elicit neutralizing antibody, including killed whole virus vaccines and fowl-pox recombinant vaccines. Antigenic drift of influenza viruses appears to be less important in causing vaccine failures in poultry as compared to humans. The cytotoxic T lymphocyte response can reduce viral shedding in mildly pathogenic avian influenza viruses, but provides questionable protection against HPAI. Influenza viruses can directly affect the immune response of infected birds, and the role of the Mx gene, interferons, and other cytokines in protection from disease remains unknown. PMID:10717293

  9. RNA interference gene therapy in dominant retinitis pigmentosa and cone-rod dystrophy mouse models caused by GCAP1 mutations

    Directory of Open Access Journals (Sweden)

    Wolfgang Baehr

    2014-04-01

    Full Text Available RNA interference (RNAi knockdown is an efficacious therapeutic strategy for silencing genes causative for dominant retinal dystrophies. To test this, we used self-complementary (sc AAV2/8 vector to develop an RNAi-based therapy in two dominant retinal degeneration mouse models. The allele-specific model expresses transgenic bovine GCAP1(Y99C establishing a rapid RP-like phenotype, whereas the nonallele-specific model expresses mouse GCAP1(L151F producing a slowly progressing cone/rod dystrophy (CORD. The late onset GCAP1(L151F-CORD mimics the dystrophy observed in human GCAP1-CORD patients. Subretinal injection of scAAV2/8 carrying shRNA expression cassettes specific for bovine or mouse GCAP1 showed strong expression at one week post-injection. In both allele-specific (GCAP1(Y99C-RP and nonallele-specific (GCAP1(L151F-CORD models of dominant retinal dystrophy, RNAi-mediated gene silencing enhanced photoreceptor survival, delayed onset of degeneration and improved visual function. Such results provide a “proof of concept” toward effective RNAi-based gene therapy mediated by scAAV2/8 for dominant retinal disease based on GCAP1 mutation. Further, nonallele-specific RNAi knockdown of GCAP1 may prove generally applicable toward the rescue of any human GCAP1-based dominant cone-rod dystrophy.

  10. Unique electrical properties of nanostructured diamond cones

    International Nuclear Information System (INIS)

    The preparation and electrical properties of diamond nanocones are reviewed, including a maskless etching process and mechanism of large-area diamond conical nanostructure arrays using a hot filament chemical vapor deposition (HFCVD) system with negatively biased substrates, and the field electron emission, gas sensing, and quantum transport properties of a diamond nanocone array or an individual diamond nanocone. Optimal cone aspect ratio and array density are investigated, along with the relationships between the cone morphologies and experimental parameters, such as the CH4/H2 ratio of the etching gas, the bias current, and the gas pressure. The reviewed experiments demonstrate the possibility of using nanostructured diamond cones as a display device element, a point electron emission source, a gas sensor or a quantum device. (topical review - low-dimensional nanostructures and devices)

  11. Cone photopigment bleaching abnormalities in diabetes.

    Science.gov (United States)

    Elsner, A E; Burns, S A; Lobes, L A; Doft, B H

    1987-04-01

    We have used a color-matching technique to obtain estimates of the optical density of cone photopigments as a function of retinal illuminance in patients with insulin-dependent diabetes mellitus (IDDM). We found that the half-bleach illuminance of some patients is abnormally high. That is, it takes more light to bleach an equivalent amount of photopigment in these patients. Since low illuminance color matches for these patients are normal, this implies that these patients have normal amounts of photopigment, but the photopigment is not bleaching normally. This result clearly points to abnormalities in the outer retina of these diabetic patients. The most likely causes of this abnormality are either decreases in the ability of the cones to absorb light, or an increased rate of regeneration of the cone photopigments. PMID:3557875

  12. [Progress in microRNAs associated with major avian viruses].

    Science.gov (United States)

    Man, Chaolai; Mu, Weitao; Zhao, Dongxue; Chang, Yang

    2015-09-01

    Recently, avian viral diseases have become one of the main models to study mechanisms of viral infections and pathogenesis. The study of regulatory relationships and mechanisms between viruses and microRNAs has also become the focus. In this review, we briefly summarize the general situations of microRNAs encoded by avian herpesviruses. Also, we analyze the regulatory relationships between tumorigenicity of avian herpesviruses and microRNAs. Additionally, the possible applications for prevention and treatment of viral diseases (such as infectious bursal disease, avian influenza and avian leucosis) using the regulatory mechanisms of microRNAs are also discussed. PMID:26955707

  13. The ultra-structural survey of Aloe Vera extract on photoreceptor layer after methanol intoxication

    Directory of Open Access Journals (Sweden)

    M Bahramian

    2015-12-01

    Full Text Available Background & aim: The photoreceptor layer is a main part of the retina. The Aloe Vera has antioxidant, antibacterial and antidiabetic effects. The aim of this study was to investigate the ultra-structure of the photoreceptor layer of male rats under the effect of methanol intoxication and protective effects of Aloe Vera extract against the methanol toxicity. Methods: The present experimental study was conducted on 30 adult male wistar rats in three groups of ten: as control, methanol intoxication, methanol intoxication receiving 400 mg/kg Aloe Vera extract for 30 days. Methanol intoxication was induced by intraperitoneal injection of 4gr/kg of methanol for 30 days. At the end of experiment, the eyes were removed and retina was separated near the optic disc and immersed in gluteraldehyde 4%. The retinal tissue was rinsed with buffer and fixed in osmium tetroxide 1% and dehydrated through a graded alcohol series. Then, the tissues were placed in a mixture of propylene oxide and resin and embedded in pure resin. Semi thin and ultrathin sections prepared and studied by transmission electron and light microscopes. Using One Way ANOVA and Tukey test data were analyzed. Result: Results showed that revealed decrement of the pathological sign in Aloe Vera-methanol group in comparison to methanol intoxication group. The outer segment loss, highly vacuolization in inner segment and condense and pyknotic nuclei were seen in methanol intoxication group. But the moderate outer segment loss, lightly vacuolization in inner segment and condense nuclei were observed in Aloe Vera-methanol group. Morphometric observations showed that the thickness of photoreceptor layer decreased in methanol intoxication group and little reduction in Aloe Vera-methanol group. The decrement of thickness in this group has significant difference with control group. But the decrement of thickness of photoreceptor layer in Aloe Vera-methanol group has no significant difference with

  14. OFD1, as a Ciliary Protein, Exhibits Neuroprotective Function in Photoreceptor Degeneration Models.

    Directory of Open Access Journals (Sweden)

    Juan Wang

    Full Text Available Ofd1 is a newly identified causative gene for Retinitis pigmentosa (RP, a photoreceptor degenerative disease. This study aimed to examine Ofd1 localization in retina and further to investigate its function in photoreceptor degeneration models. Ofd1 localization in rat retina was examined using immunofluorescence. N-methyl-N-nitrosourea (MNU-induced rats and Royal College of Surgeons (RCS rats were used as photoreceptor degeneration models. The expression pattern of Ofd1, other ciliary associated genes and Wnt signaling pathway genes were examined in rat models. Furthermore, pEGFP-Ofd1-CDS and pSUPER-Ofd1-shRNA were constructed to overexpress and knockdown the expression level in 661W and R28 cells. MNU was also used to induce cell death. Cilia formation was observed using immunocytochemistry (ICC. Reactive oxygen species (ROS were detected using the 2', 7'-Dichlorofluorescin diacetate (DCFH-DA assay. Apoptosis genes expression was examined using qRT-PCR, Western blotting and fluorescence-activated cell sorting (FACS. Ofd1 localized to outer segments of rat retina photoreceptors. Ofd1 and other ciliary proteins expression levels increased from the 1st and 4th postnatal weeks and decreased until the 6th week in the RCS rats, while their expression consistently decreased from the 1st and 7th day in the MNU rats. Moreover, Wnt signaling pathway proteins expression was significantly up-regulated in both rat models. Knockdown of Ofd1 expression resulted in a smaller population, shorter length of cell cilia, and lower cell viability. Ofd1 overexpression partially attenuated MNU toxic effects by reducing ROS levels and mitigating apoptosis. To the best of our knowledge, this is the first study demonstrating Ofd1 localization and its function in rat retina and in retinal degeneration rat models. Ofd1 plays a role in controlling photoreceptor cilium length and number. Importantly, it demonstrates a neuroprotective function by protecting the photoreceptor

  15. Avian influenza surveillance of wild birds

    Science.gov (United States)

    Slota, Paul

    2007-01-01

    The President's National Strategy for Pandemic Influenza directs federal agencies to expand the surveillance of United States domestic livestock and wildlife to ensure early warning of hightly pathogenic avian influenza (HPAI) in the U.S. The immediate concern is a potential introduction of HPAI H5N1 virus into the U.S. The presidential directive resulted in the U.S. Interagency Strategic Plan for Early Detection of H5N1 Highly Pathogenic Avian Influenza in Wild Migratory Birds (referred to as the Wild Bird Surveillance Plan or the Plan).

  16. Composting for Avian Influenza Virus Elimination

    OpenAIRE

    Elving, Josefine; Emmoth, Eva; Albihn, Ann; Vinnerås, Björn; Ottoson, Jakob

    2012-01-01

    Effective sanitization is important in viral epizootic outbreaks to avoid further spread of the pathogen. This study examined thermal inactivation as a sanitizing treatment for manure inoculated with highly pathogenic avian influenza virus H7N1 and bacteriophages MS2 and ϕ6. Rapid inactivation of highly pathogenic avian influenza virus H7N1 was achieved at both mesophilic (35°C) and thermophilic (45 and 55°C) temperatures. Similar inactivation rates were observed for bacteriophage ϕ6, while b...

  17. Avian Influenza: Should China Be Alarmed?

    OpenAIRE

    Su, Zhaoliang; Xu, Huaxi; Chen, Jianguo

    2007-01-01

    Avian influenza has emerged as one of the primary public health concern of the 21st century. Influenza strain H5N1 is capable of incidentally infecting humans and other mammals. Since their reemergence in 2003, highly pathogenic avian influenza A (H5N1) viruses have been transmitted from poultry to humans (by direct or indirect contact with infected birds) in several provinces of Mainland China, which has resulted in 22 cases of human infection and has created repercussions for the Chinese ec...

  18. Avian influenza virus risk assessment in falconry

    OpenAIRE

    Lüschow Dörte; Lierz Peter; Jansen Andreas; Harder Timm; Hafez Hafez; Kohls Andrea; Schweiger Brunhilde; Lierz Michael

    2011-01-01

    Abstract Background There is a continuing threat of human infections with avian influenza viruses (AIV). In this regard falconers might be a potential risk group because they have close contact to their hunting birds (raptors such as falcons and hawks) as well as their avian prey such as gulls and ducks. Both (hunting birds and prey birds) seem to be highly susceptible to some AIV strains, especially H5N1. We therefore conducted a field study to investigate AIV infections in falconers, their ...

  19. Relationship between mitochondrial DNA damage and photoreceptor death in developing and adult retina, assessed in normal and degenerative rat strains.

    Science.gov (United States)

    Bravo-Nuevo, Arturo; Williams, Neal K; Valter, Krisztina; Stone, Jonathan

    2007-09-01

    In this study, we used Real-Time PCR to study the correlation of mtDNA deletions and photoreceptor death by apoptosis in one normal (SD) and two different degenerative (RCS and P23H) rat strains. Our results show that, in the SD and RCS strains, mtDNA deletion frequency increased and fell during neonatal life, correlating with rates of photoreceptor death during the critical period of photoreceptor development, and into adulthood. Results suggest that mitochondrial damage occurs in close association with photoreceptor death, in the normal (SD) and fast degenerative (RCS) retinas. The lack of a similar association was observed in the slowly degenerative P23H-3 strain. PMID:17644492

  20. A Cone Pseudo-differential Calculus

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@  The calculus of pseudo-differential operators on singular spaces and theconcept of ellipti-city in operator algebras on manifolds with singularitieshave become an enormous challenge for analysists. The so-called cone algebras(with discrete and continuous asymptotics) are investigated by manymathematicians, especially by B. W. Schulze, who developed and enrichedcone and edge pseudo-differential calculus, see Schulze[4-7], Rempel and Schulze [2, 3]. In this note,we construct a cone pseudo-differentialcalculus for operators which respect conormal asymptotics of a prescribedasymptotic type.

  1. Lightcone: Light-cone generating script

    Science.gov (United States)

    Bernyk, Max

    2014-03-01

    Lightcone works with simulated galaxy data stored in a relational database to rearrange the data in a shape of a light-cone; simulated galaxy data is expected to be in a box volume. The light-cone constructing script works with output from the SAGE semi-analytic model, but will work with any other model that has galaxy positions (and other properties) saved per snapshots of the simulation volume distributed in time. The database configuration file is set up for PostgreSQL RDBMS, but can be modified for use with any other SQL database.

  2. Thermal emissivity of avian eggshells.

    Science.gov (United States)

    Björn, Lars Olof; Bengtson, Sven-Axel; Li, Shaoshan; Hecker, Christoph; Ullah, Saleem; Roos, Arne; Nilsson, Annica M

    2016-04-01

    The hypothesis has been tested that evolution has resulted in lower thermal emissivity of eggs of birds breeding openly in cold climates than of eggs of birds that nest under protective covering or in warmer climates. Directional thermal emissivity has been estimated from directional-hemispherical reflectance spectra. Due to several methodological difficulties the absolute emissivity is not accurately determined, but differences between species are obvious. Most notably, small waders of the genus Calidris, breeding in cold climates on the tundra, and in most cases with uniparental nest attendance, have low directional emissivity of their eggshells, about 0.92 when integration is carried out for wavelengths up to 16μm. Species belonging to Galloanserinae have the highest directional emissivity, about 0.96, of their eggs. No differences due to climate or breeding conditions were found within this group. Eggs of most other birds tested possess intermediate emissivity, but the values for Pica pica and Corvus corone cornix are as low as for Calidris. Large species-dependent differences in spectral reflectance were found at specific wavelengths. For instance, at 4.259μm the directional-hemispherical reflectance for galliforms range from 0.05 to 0.09, while for Fratercula arctica and Fulmarus glacialis it is about 0.3. The reflection peaks at 6.5 and 11.3μm due to calcite are differentially attenuated in different species. In conclusion, the hypothesis that evolution has resulted in lower thermal emissivity of bird eggs being exposed in cold climates is not supported by our results. The emissivity is not clearly related to nesting habits or climate, and it is unlikely that the small differences observed are ecologically important. The spectral differences between eggs that nevertheless exist should be taken into account when using infrared thermometers for estimating the surface temperature of avian eggs. PMID:27033033

  3. Morphological and biochemical studies of canine progressive rod-cone degeneration. 3H-fucose autoradiography

    International Nuclear Information System (INIS)

    Visual cell pathology and rod outer segment renewal were investigated in normal and PRCD-affected miniature poodles using 3H-fucose autoradiography. Twenty-four hours following the intravitreal injection of 3H-fucose, label accumulated diffusely over cone OS and in a banded pattern at the rod OS base. In normal rods, the band of 3H-label was displaced sclerad with time. PRCD-affected rods in the early stages of the disease (stages 0-1) also showed a similar 3H-label pattern but a significantly (P less than 0.001) reduced renewal rate (control = 2.35 +/- 0.43 mu/24 hr; affected = 0.99 +/- mu/24 hr). This abnormal renewal rate was present in central, equatorial, and peripheral visual cells and was not associated with the presence or density of pigment in the RPE cell layer. Biochemical studies indicated that the 3H-label was present as an integral membrane component in the rod OS and confirmed that canine rhodopsin is a fucosylated glycoprotein. The 3H-band in the rod OS layer disappeared in stage 2 of the disease; diffuse label now was present over rod OS that had decreased length and were reduced in number. At this stage of the disease, interphotoreceptor space was invaded by phagocytic cells, and photoreceptor nuclei were lost from the outer nuclear layer. These late degenerative changes were more extensive in the superior and inferior retinal meridians

  4. Retinal ganglion cells survive and maintain normal dendritic morphology in a mouse model of inherited photoreceptor degeneration

    OpenAIRE

    Mazzoni, Francesca; Novelli, Elena; Strettoi, Enrica

    2008-01-01

    Retinitis Pigmentosa (RP), a family of inherited disorders characterized by progressive photoreceptor death, is a leading cause of blindness with no available cure. Despite the genetic heterogeneity underlying the disease, recent data on animal models show that the degeneration of photoreceptors triggers stereotyped remodeling among their postsynaptic partners. In particular, bipolar and horizontal cells might undergo dendritic atrophy and secondary death. The aim of this study was to investi...

  5. Optical coherence tomography of the photoreceptor layer in the healthy eye and in eyes with hereditary macular dystrophy

    International Nuclear Information System (INIS)

    Optical coherence tomography is primarily used for the evaluation of pronounced alterations of the retinal architecture, such as in macular holes, epiretinal gliosis, intra- and subretinal fluid accumulation as well as retinal atrophy. Ultrahigh resolution OCT devices also allow the assessment of discrete alterations of the photoreceptor layer and the retinal pigment epithelium. On the basis of cases from two different macular dystrophies, the importance of the evaluation of the photoreceptor layer and its correlation with visual acuity is demonstrated.(author)

  6. Shatter Cones Formed in a MEMIN Impact Cratering Experiment

    Science.gov (United States)

    Kenkmann, T.; Poelchau, M. H.; Trullenque, G.; Hoerth, T.; Schäfer, F.; Thoma, K.; Deutsch, A.

    2012-09-01

    Experimentally formed shatter cones help to constrain the physical boundary conditions required for their formation. We produced shatter cones in porous sandstone at 4.3 kJ shock loading. Their surfaces contain vesicular melt films.

  7. BANACH CONTRACTION PRINCIPLE ON CONE RECTANGULAR METRIC SPACES

    Directory of Open Access Journals (Sweden)

    Ismat Beg

    2009-08-01

    Full Text Available We introduce the notion of cone rectangular metric space and prove {sc Banach} contraction mapping principle in cone rectangular metric space setting. Our result extends recent known results.

  8. Derivation of human differential photoreceptor-like cells from the iris by defined combinations of CRX, RX and NEUROD.

    Directory of Open Access Journals (Sweden)

    Yuko Seko

    Full Text Available Examples of direct differentiation by defined transcription factors have been provided for beta-cells, cardiomyocytes and neurons. In the human visual system, there are four kinds of photoreceptors in the retina. Neural retina and iris-pigmented epithelium (IPE share a common developmental origin, leading us to test whether human iris cells could differentiate to retinal neurons. We here define the transcription factor combinations that can determine human photoreceptor cell fate. Expression of rhodopsin, blue opsin and green/red opsin in induced photoreceptor cells were dependent on combinations of transcription factors: A combination of CRX and NEUROD induced rhodopsin and blue opsin, but did not induce green opsin; a combination of CRX and RX induced blue opsin and green/red opsin, but did not induce rhodopsin. Phototransduction-related genes as well as opsin genes were up-regulated in those cells. Functional analysis; i.e. patch clamp recordings, clearly revealed that generated photoreceptor cells, induced by CRX, RX and NEUROD, responded to light. The response was an inward current instead of the typical outward current. These data suggest that photosensitive photoreceptor cells can be generated by combinations of transcription factors. The combination of CRX and RX generate immature photoreceptors: and additional NEUROD promotes maturation. These findings contribute substantially to a major advance toward eventual cell-based therapy for retinal degenerative diseases.

  9. Cav1.4 L-Type Calcium Channels Contribute to Calpain Activation in Degenerating Photoreceptors of rd1 Mice

    Science.gov (United States)

    Schön, Christian; Paquet-Durand, François; Michalakis, Stylianos

    2016-01-01

    Retinitis pigmentosa is an inherited blinding disorder characterized by progressive degeneration and loss of photoreceptors. The exact mechanism of degeneration and cell death of photoreceptors is not known, but is thought to involve disturbed Ca2+—signaling. Ca2+ can enter the photoreceptor cell via outer segment cyclic nucleotide-gated (CNG) channels or synaptic Cav1.4 L-type voltage-gated calcium channels (VGCC). Previously, we have shown that genetic ablation of the Cngb1 gene encoding the B subunit of the rod CNG channel delays the fast progressing degeneration in the rd1 mutant mouse model of retinitis pigmentosa. In this study, we crossbred rd1 mice with the Cacna1f-deficient mouse lacking the Cav1.4 α1 subunit of the L-type VGCC. Longitudinal in vivo examinations of photoreceptor layer thickness by optical coherence tomography revealed a significant, but not sustained delay of retinal degeneration in Cacna1f x rd1 double mutant mice compared to rd1 mice. This was accompanied by a reduction of TUNEL positive cells in the early phase of rod degeneration. Remarkably, Cacna1f x rd1 double mutant mice displayed a strong decrease in the activation of the Ca2+-dependent protease calpain during photoreceptor loss. Our results show that genetic deletion of the synaptic Cav1.4 L-type VGCCs impairs calpain activation and leads to a short-term preservation of photoreceptors in the rd1 mouse. PMID:27270916

  10. Rod-cone interaction in patients with fundus flavimaculatus.

    OpenAIRE

    Schneider, T.; Zrenner, E.

    1987-01-01

    Dark adaptation and the rise of cone flicker threshold (25 Hz) during dark adaptation were measured psychophysically in three patients with fundus flavimaculatus. The dark adaptation curve showed a delayed rod-cone break but a normal final rod threshold in all these patients. However, the rise of cone flicker threshold during dark adaptation was not delayed and also reached a normal final value. This indicates that the delay in rod dark adaptation does not influence the rise of cone flicker t...

  11. Decline of electrogenic Na+/K+ pump activity in rod photoreceptors during maintained illumination

    OpenAIRE

    1986-01-01

    Light-evoked changes in membrane voltage were recorded intracellularly from rod photoreceptors in the isolated retina preparation of the toad, Bufo marinus, during superfusion with a solution containing pharmacological agents that blocked voltage-dependent conductances. Under these conditions, the amplitude of the hyperpolarizing photoresponse became much greater than under control conditions. The results of several experiments support the conclusion that this increase in photoresponse amplit...

  12. The hypothalamic photoreceptors regulating seasonal reproduction in birds: A prime role for VA opsin.

    OpenAIRE

    Garcia-Fernandez, JM; Cernuda-Cernuda, R.; Davies, WL; Rodgers, J.; Turton, M.; Peirson, SN; Follett, BK; Halford, S; Hughes, S.; Hankins, MW; Foster, RG

    2015-01-01

    Extraretinal photoreceptors located within the medio-basal hypothalamus regulate the photoperiodic control of seasonal reproduction in birds. An action spectrum for this response describes an opsin photopigment with a λmax of ∼492nm. Beyond this however, the specific identity of the photopigment remains unresolved. Several candidates have emerged including rod-opsin; melanopsin (OPN4); neuropsin (OPN5); and vertebrate ancient (VA) opsin. These contenders are evaluated against key criteria use...

  13. Honeybees (Apis mellifera learn color discriminations via differential conditioning independent of long wavelength (green photoreceptor modulation.

    Directory of Open Access Journals (Sweden)

    David H Reser

    Full Text Available BACKGROUND: Recent studies on colour discrimination suggest that experience is an important factor in how a visual system processes spectral signals. In insects it has been shown that differential conditioning is important for processing fine colour discriminations. However, the visual system of many insects, including the honeybee, has a complex set of neural pathways, in which input from the long wavelength sensitive ('green' photoreceptor may be processed either as an independent achromatic signal or as part of a trichromatic opponent-colour system. Thus, a potential confound of colour learning in insects is the possibility that modulation of the 'green' photoreceptor could underlie observations. METHODOLOGY/PRINCIPAL FINDINGS: We tested honeybee vision using light emitting diodes centered on 414 and 424 nm wavelengths, which limit activation to the short-wavelength-sensitive ('UV' and medium-wavelength-sensitive ('blue' photoreceptors. The absolute irradiance spectra of stimuli was measured and modelled at both receptor and colour processing levels, and stimuli were then presented to the bees in a Y-maze at a large visual angle (26°, to ensure chromatic processing. Sixteen bees were trained over 50 trials, using either appetitive differential conditioning (N = 8, or aversive-appetitive differential conditioning (N = 8. In both cases the bees slowly learned to discriminate between the target and distractor with significantly better accuracy than would be expected by chance. Control experiments confirmed that changing stimulus intensity in transfers tests does not significantly affect bee performance, and it was possible to replicate previous findings that bees do not learn similar colour stimuli with absolute conditioning. CONCLUSION: Our data indicate that honeybee colour vision can be tuned to relatively small spectral differences, independent of 'green' photoreceptor contrast and brightness cues. We thus show that colour vision is

  14. Photoreceptor Degeneration Changes Magnetic Resonance Imaging Features in a Mouse Model of Retinitis Pigmentosa

    OpenAIRE

    Wang, Qing; Song, Sheng-Kwei; Zhang, Huiying; Berkowitz, Bruce A.; Chen, Shiming; Wickline, Samuel A.; Chen, Junjie

    2011-01-01

    Retinal degeneration-1 (rd1) mice are animal models of retinitis pigmentosa, a blinding disease caused by photoreceptor cell degeneration. This study aims to determine magnetic resonance imaging (MRI) changes in retinas of 1- and 3-month-old rd1 mice. Apparent diffusion coefficient in retina was measured using diffusion MRI. The blood-retinal barrier leakage was evaluated using gadolinium-diethylenetriaminepentaacetic acid-enhanced T1-weighted MRI before and after systemic gadolinium-diethyle...

  15. Photoreceptor sectral sensitivities in terrestrial animals: adaptations for luminance and colour vision

    OpenAIRE

    Osorio, D; Vorobyev, M

    2005-01-01

    This review outlines how eyes of terrestrial vertebrates and insects meet the competing requirements of coding both spatial and spectral information. There is no unique solution to this problem. Thus, mammals and honeybees use their long-wavelength receptors for both achromatic (luminance) and colour vision, whereas flies and birds probably use separate sets of photoreceptors for the two purposes. In particular, we look at spectral tuning and diversification among ‘long-wavelength’ receptors ...

  16. PixE promotes dark oligomerization of the BLUF photoreceptor PixD

    OpenAIRE

    Yuan, Hua; Bauer, Carl E

    2008-01-01

    Cyanobacteria perceive and move (phototax) in response to blue light. In this study, we demonstrate that the PixD blue light-sensing using FAD (BLUF) photoreceptor that governs this response undergoes changes in oligomerization state upon illumination. Under dark conditions we observed that PixD forms a large molecular weight complex with another protein called PixE. Stoicheometric analyses, coupled with sedimentation equilibrium and size exclusion chromatography, demonstrates that PixE drive...

  17. The role of carcinine in signaling at the Drosophila photoreceptor synapse.

    Directory of Open Access Journals (Sweden)

    Brendan A Gavin

    2007-12-01

    Full Text Available The Drosophila melanogaster photoreceptor cell has long served as a model system for researchers focusing on how animal sensory neurons receive information from their surroundings and translate this information into chemical and electrical messages. Electroretinograph (ERG analysis of Drosophila mutants has helped to elucidate some of the genes involved in the visual transduction pathway downstream of the photoreceptor cell, and it is now clear that photoreceptor cell signaling is dependent upon the proper release and recycling of the neurotransmitter histamine. While the neurotransmitter transporters responsible for clearing histamine, and its metabolite carcinine, from the synaptic cleft have remained unknown, a strong candidate for a transporter of either substrate is the uncharacterized inebriated protein. The inebriated gene (ine encodes a putative neurotransmitter transporter that has been localized to photoreceptor cells in Drosophila and mutations in ine result in an abnormal ERG phenotype in Drosophila. Loss-of-function mutations in ebony, a gene required for the synthesis of carcinine in Drosophila, suppress components of the mutant ine ERG phenotype, while loss-of-function mutations in tan, a gene necessary for the hydrolysis of carcinine in Drosophila, have no effect on the ERG phenotype in ine mutants. We also show that by feeding wild-type flies carcinine, we can duplicate components of mutant ine ERGs. Finally, we demonstrate that treatment with H(3 receptor agonists or inverse agonists rescue several components of the mutant ine ERG phenotype. Here, we provide pharmacological and genetic epistatic evidence that ine encodes a carcinine neurotransmitter transporter. We also speculate that the oscillations observed in mutant ine ERG traces are the result of the aberrant activity of a putative H(3 receptor.

  18. TRP, TRPL and cacophony channels mediate Ca2+ influx and exocytosis in photoreceptors axons in Drosophila.

    Directory of Open Access Journals (Sweden)

    Guadalupe Astorga

    Full Text Available In Drosophila photoreceptors Ca(2+-permeable channels TRP and TRPL are the targets of phototransduction, occurring in photosensitive microvilli and mediated by a phospholipase C (PLC pathway. Using a novel Drosophila brain slice preparation, we studied the distribution and physiological properties of TRP and TRPL in the lamina of the visual system. Immunohistochemical images revealed considerable expression in photoreceptors axons at the lamina. Other phototransduction proteins are also present, mainly PLC and protein kinase C, while rhodopsin is absent. The voltage-dependent Ca(2+ channel cacophony is also present there. Measurements in the lamina with the Ca(2+ fluorescent protein G-CaMP ectopically expressed in photoreceptors, revealed depolarization-induced Ca(2+ increments mediated by cacophony. Additional Ca(2+ influx depends on TRP and TRPL, apparently functioning as store-operated channels. Single synaptic boutons resolved in the lamina by FM4-64 fluorescence revealed that vesicle exocytosis depends on cacophony, TRP and TRPL. In the PLC mutant norpA bouton labeling was also impaired, implicating an additional modulation by this enzyme. Internal Ca(2+ also contributes to exocytosis, since this process was reduced after Ca(2+-store depletion. Therefore, several Ca(2+ pathways participate in photoreceptor neurotransmitter release: one is activated by depolarization and involves cacophony; this is complemented by internal Ca(2+ release and the activation of TRP and TRPL coupled to Ca(2+ depletion of internal reservoirs. PLC may regulate the last two processes. TRP and TRPL would participate in two different functions in distant cellular regions, where they are opened by different mechanisms. This work sheds new light on the mechanism of neurotransmitter release in tonic synapses of non-spiking neurons.

  19. Website for avian flu information and bioinformatics

    Institute of Scientific and Technical Information of China (English)

    GAO; George; Fu

    2009-01-01

    Highly pathogenic influenza A virus H5N1 has spread out worldwide and raised the public concerns. This increased the output of influenza virus sequence data as well as the research publication and other reports. In order to fight against H5N1 avian flu in a comprehensive way, we designed and started to set up the Website for Avian Flu Information (http://www.avian-flu.info) from 2004. Other than the influenza virus database available, the website is aiming to integrate diversified information for both researchers and the public. From 2004 to 2009, we collected information from all aspects, i.e. reports of outbreaks, scientific publications and editorials, policies for prevention, medicines and vaccines, clinic and diagnosis. Except for publications, all information is in Chinese. Till April 15, 2009, the cumulative news entries had been over 2000 and research papers were approaching 5000. By using the curated data from Influenza Virus Resource, we have set up an influenza virus sequence database and a bioinformatic platform, providing the basic functions for the sequence analysis of influenza virus. We will focus on the collection of experimental data and results as well as the integration of the data from the geological information system and avian influenza epidemiology.

  20. Website for avian flu information and bioinformatics

    Institute of Scientific and Technical Information of China (English)

    LIU Di; LIU Quan-He; WU Lin-Huan; LIU Bin; WU Jun; LAO Yi-Mei; LI Xiao-Jing; GAO George Fu; MA Jun-Cai

    2009-01-01

    Highly pathogenic influenza A virus H5N1 has spread out worldwide and raised the public concerns. This increased the output of influenza virus sequence data as well as the research publication and other reports. In order to fight against H5N1 avian flu in a comprehensive way, we designed and started to set up the Website for Avian Flu Information (http://www.avian-flu.info) from 2004. Other than the influenza virus database available, the website is aiming to integrate diversified information for both researchers and the public. From 2004 to 2009, we collected information from all aspects, i.e. reports of outbreaks, scientific publications and editorials, policies for prevention, medicines and vaccines, clinic and diagnosis. Except for publications, all information is in Chinese. Till April 15, 2009, the cumulative news entries had been over 2000 and research papers were approaching 5000. By using the curated data from Influenza Virus Resource, we have set up an influenza virus sequence database and a bioin-formatic platform, providing the basic functions for the sequence analysis of influenza virus. We will focus on the collection of experimental data and results as well as the integration of the data from the geological information system and avian influenza epidemiology.

  1. Avian Influenza Risk Perception, Europe and Asia

    OpenAIRE

    de Zwart, Onno; Veldhuijzen, Irene K; Elam, Gillian; Aro, Arja R; Abraham, Thomas; Bishop, George D.; Richardus, Jan Hendrik; Brug, Johannes

    2007-01-01

    During autumn 2005, we conducted 3,436 interviews in European and Asian countries. We found risk perceptions of avian influenza to be at an intermediate level and beliefs of efficacy to be slightly lower. Risk perceptions were higher in Asia than Europe; efficacy beliefs were lower in Europe than Asia.

  2. Avian Influenza Outbreaks in Chickens, Bangladesh

    OpenAIRE

    Paritosh K Biswas; Christensen, Jens P.; Ahmed, Syed S.U.; Barua, Himel; Das, Ashutosh; Rahman, Mohammed H.; Giasuddin, Mohammad; Hannan, Abu S. M. A.; Habib, Mohammad A.; Ahad, Abdul; Rahman, Abu S.M.S.; Faruque, Rayhan; Nitish C Debnath

    2008-01-01

    To determine the epidemiology of outbreaks of avian influenza A virus (subtypes H5N1, H9N2) in chickens in Bangladesh, we conducted surveys and examined virus isolates. The outbreak began in backyard chickens. Probable sources of infection included egg trays and vehicles from local live bird markets and larger live bird markets.

  3. Avian pox in Magellanic Penguins (Spheniscus magellanicus).

    Science.gov (United States)

    Kane, Olivia J; Uhart, Marcela M; Rago, Virginia; Pereda, Ariel J; Smith, Jeffrey R; Van Buren, Amy; Clark, J Alan; Boersma, P Dee

    2012-07-01

    Avian pox is an enveloped double-stranded DNA virus that is mechanically transmitted via arthropod vectors or mucosal membrane contact with infectious particles or birds. Magellanic Penguins (Spheniscus magellanicus) from two colonies (Punta Tombo and Cabo Dos Bahías) in Argentina showed sporadic, nonepidemic signs of avian pox during five and two of 29 breeding seasons (1982-2010), respectively. In Magellanic Penguins, avian pox expresses externally as wart-like lesions around the beak, flippers, cloaca, feet, and eyes. Fleas (Parapsyllus longicornis) are the most likely arthropod vectors at these colonies. Three chicks with cutaneous pox-like lesions were positive for Avipoxvirus and revealed phylogenetic proximity with an Avipoxvirus found in Black-browed Albatross (Thalassarche melanophrys) from the Falkland Islands in 1987. This proximity suggests a long-term circulation of seabird Avipoxviruses in the southwest Atlantic. Avian pox outbreaks in these colonies primarily affected chicks, often resulted in death, and were not associated with handling, rainfall, or temperature. PMID:22740548

  4. Avian Disease & Oncology Lab (ADOL) Research Update

    Science.gov (United States)

    Employing Genomics, Epigenetics, and Immunogenetics to Control Diseases Induced by Avian Tumor Viruses - Gene expression is a major factor accounting for phenotypic variation. Taking advantage of allele-specific expression (ASE) screens, we found the use of genetic markers was superior to traditiona...

  5. 76 FR 4046 - Highly Pathogenic Avian Influenza

    Science.gov (United States)

    2011-01-24

    ... poultry caused by a paramyxovirus. END is one of most infectious diseases of poultry in the world. A death... avian influenza (HPAI) is an extremely infectious and potentially fatal form of the disease in birds and... birds' or poultry's freedom from END, HPAI subtype H5N1, and other communicable diseases,...

  6. THE TANGENT CONES ON CONSTRAINT QUALIFICATIONS IN OPTIMIZATION PROBLEMS

    Institute of Scientific and Technical Information of China (English)

    Huang Longguang

    2008-01-01

    This article proposes a few tangent cones, which are relative to the constraint qualifications of optimization problems. With the upper and lower directional derivatives of an objective function, the characteristics of cones on the constraint qualifications are presented. The interrelations among the constraint qualifications, a few cones involved,and level sets of upper and lower directional derivatives are derived.

  7. Genetics Home Reference: cone-rod dystrophy

    Science.gov (United States)

    ... common cause of autosomal recessive cone-rod dystrophy , accounting for 30 to 60 percent of cases. At ... 1 ClinicalTrials.gov (1 link) ClinicalTrials.gov Scientific articles on PubMed (1 link) PubMed OMIM (21 links) ...

  8. Final design report for cone penetrometer platform

    Energy Technology Data Exchange (ETDEWEB)

    Seda, R.Y., Westinghouse Hanford

    1996-08-13

    The final design report documents the completion of the design review meetings for acceptance of the cone penetrometer from the vendor. All design comments have been dispositioned and closed. Open items dealt with completion of the safety assessment,operational procedures, operational testing and readiness review.

  9. Performance analysis of cone detection algorithms.

    Science.gov (United States)

    Mariotti, Letizia; Devaney, Nicholas

    2015-04-01

    Many algorithms have been proposed to help clinicians evaluate cone density and spacing, as these may be related to the onset of retinal diseases. However, there has been no rigorous comparison of the performance of these algorithms. In addition, the performance of such algorithms is typically determined by comparison with human observers. Here we propose a technique to simulate realistic images of the cone mosaic. We use the simulated images to test the performance of three popular cone detection algorithms, and we introduce an algorithm which is used by astronomers to detect stars in astronomical images. We use Free Response Operating Characteristic (FROC) curves to evaluate and compare the performance of the four algorithms. This allows us to optimize the performance of each algorithm. We observe that performance is significantly enhanced by up-sampling the images. We investigate the effect of noise and image quality on cone mosaic parameters estimated using the different algorithms, finding that the estimated regularity is the most sensitive parameter. PMID:26366758

  10. Determination of Photoreceptor Cell Spectral Sensitivity in an Insect Model from In Vivo Intracellular Recordings.

    Science.gov (United States)

    McCulloch, Kyle J; Osorio, Daniel; Briscoe, Adriana D

    2016-01-01

    Intracellular recording is a powerful technique used to determine how a single cell may respond to a given stimulus. In vision research, intracellular recording has historically been a common technique used to study sensitivities of individual photoreceptor cells to different light stimuli that is still being used today. However, there remains a dearth of detailed methodology in the literature for researchers wishing to replicate intracellular recording experiments in the eye. Here we present the insect as a model for examining eye physiology more generally. Insect photoreceptor cells are located near the surface of the eye and are therefore easy to reach, and many of the mechanisms involved in vision are conserved across animal phyla. We describe the basic procedure for in vivo intracellular recording of photoreceptor cells in the eye of a butterfly, with the goal of making this technique more accessible to researchers with little prior experience in electrophysiology. We introduce the basic equipment needed, how to prepare a live butterfly for recording, how to insert a glass microelectrode into a single cell, and finally the recording procedure itself. We also explain the basic analysis of raw response data for determining spectral sensitivity of individual cell types. Although our protocol focuses on determining spectral sensitivity, other stimuli (e.g., polarized light) and variations of the method are applicable to this setup. PMID:26966935

  11. Rhodopsin molecular contrast imaging by optical coherence tomography for functional assessment of photoreceptors (Conference Presentation)

    Science.gov (United States)

    Nafra, Zahra; Liu, Tan; Jiao, Shuliang

    2016-03-01

    Rhodopsin, the light-sensing molecule in the outer segments of rod photoreceptors, is responsible for converting light into neuronal signals in a process known as phototransduction. Rhodopsin is thus a functional biomarker for rod photoreceptors. We developed a novel technology based on visible-light optical coherence tomography (VIS-OCT) for in vivo molecular imaging of rhodopsin. The depth resolution of OCT allows the visualization of the location where the change of optical absorption occurs and provides a potentially accurate assessment of rhodopsin content by segmentation of the image at the location. A broadband supercontinuum laser, whose filtered output was centered at 520 nm, was used as the illuminating light source. To test the capabilities of the system on rhodopsin mapping we imaged the retina of albino rats. The rats were dark adapted before imaging. An integrated near infrared OCT was used to guide the alignment in dark. VIS-OCT three-dimensional images were then acquired under dark- and light- adapted states sequentially. Rhodopsin distribution was calculated from the differential image. The rhodopsin distributions can be displayed in both en face view and depth-resolved cross-sectional image. Rhodopsin OCT can be used to quantitatively image rhodopsin distribution and thus assess the distribution of functional rod photoreceptors in the retina. Rhodopsin OCT can bring significant impact into ophthalmic clinics by providing a tool for the diagnosis and severity assessment of a variety of retinal conditions.

  12. Tetramethylpyrazine protected photoreceptor cells of rats by modulating nuclear translocation of NF-κB

    Institute of Scientific and Technical Information of China (English)

    Jin-nan YANG; Jin-mao CHEN; Lin LUO; Shao-chun LIN; Dai LI; Shi-xing HU

    2005-01-01

    Aim: To evaluate the effect of tetramethylpyrazine (TMP) injection on retinal damage induced by N-methyl-N-nitrosourea (MNU) in rats and on nuclear factorkappa B (NF-κB) family members.Methods: Female Sprague-Dawley (SD) rats were randomly divided into groups: (i), control group; (ii), model group; and (iii),TMP-injection groups, in which the rats were subdivided into 40 mg/kg, 80 mg/kg and 160 mg/kg groups.Drugs were injected ip into 47-day-old SD rats once a day.physiological saline.All rats were killed at different times after MNU or physiological saline treatment.The apoptotic index of photoreceptor cells was calculated by TUNEL labeling; retinal damage was evaluated based on retinal thickness and the expression of NF-κB family members was detected by Western blot.Results: TMP injections, in a dose-dependent manner, suppressed photoreceptor cell apoptosis and decreased its loss in the peripheral retina.As compared with the MNU-treated group, TMP injection at a dose of 160 mg/kg also timedependently upregulated the NF-κB/p65 protein level in the nucleus and downregulated the Iκ Bα protein level in the cytoplasm.However, no protective effect of TMP injection on MNU-induced central retinal damage was found.Conclusion: TMP injection partially protects against MNU-induced retiral damage by upregulating the nuclear translocation of p65 to inhibit photoreceptor cells apoptosis.

  13. In vivo knockdown of Piccolino disrupts presynaptic ribbon morphology in mouse photoreceptor synapses

    Directory of Open Access Journals (Sweden)

    Hanna Regus-Leidig

    2014-09-01

    Full Text Available Piccolo is the largest known cytomatrix protein at active zones of chemical synapses. A growing number of studies on conventional chemical synapses assign Piccolo a role in the recruitment and integration of molecules relevant for both endo- and exocytosis of synaptic vesicles, the dynamic assembly of presynaptic F-actin, as well as the proteostasis of presynaptic proteins, yet a direct function in the structural organization of the active zone has not been uncovered in part due to the expression of multiple alternatively spliced isoforms. We recently identified Piccolino, a Piccolo splice variant specifically expressed in sensory ribbon synapses of the eye and ear. Here we down regulated Piccolino in vivo via an adeno-associated virus-based RNA interference approach and explored the impact on the presynaptic structure of mouse photoreceptor ribbon synapses. Detailed immunocytochemical light and electron microscopical analysis of Piccolino knockdown in photoreceptors revealed a hitherto undescribed photoreceptor ribbon synaptic phenotype with striking morphological changes of synaptic ribbon ultrastructure.

  14. An Unexpected Diversity of Photoreceptor Classes in the Longfin Squid, Doryteuthis pealeii.

    Directory of Open Access Journals (Sweden)

    Alexandra C N Kingston

    Full Text Available Cephalopods are famous for their ability to change color and pattern rapidly for signaling and camouflage. They have keen eyes and remarkable vision, made possible by photoreceptors in their retinas. External to the eyes, photoreceptors also exist in parolfactory vesicles and some light organs, where they function using a rhodopsin protein that is identical to that expressed in the retina. Furthermore, dermal chromatophore organs contain rhodopsin and other components of phototransduction (including retinochrome, a photoisomerase first found in the retina, suggesting that they are photoreceptive. In this study, we used a modified whole-mount immunohistochemical technique to explore rhodopsin and retinochrome expression in a number of tissues and organs in the longfin squid, Doryteuthis pealeii. We found that fin central muscles, hair cells (epithelial primary sensory neurons, arm axial ganglia, and sucker peduncle nerves all express rhodopsin and retinochrome proteins. Our findings indicate that these animals possess an unexpected diversity of extraocular photoreceptors and suggest that extraocular photoreception using visual opsins and visual phototransduction machinery is far more widespread throughout cephalopod tissues than previously recognized.

  15. Flexible cone impact dynamics based on space probe-cone docking mechanism

    Science.gov (United States)

    Han, Wei; Huang, YiYong; Chen, XiaoQian; Zhang, Xiang

    2014-01-01

    The theoretical model of docking impact dynamics based on flexible cone is presented according to Föppl-von Kármán's non-linear differential equations and Hertz contact theory. Finite difference technique is used to solve this theoretical model. Results of the theoretical model show good agreement with the experimental and ANSYS/LS-DYNA simulation results. In addition, the influence of flexible cone parameters on impact process is discussed based on theoretical model systemically.

  16. Perturbation theory in light-cone quantization

    Energy Technology Data Exchange (ETDEWEB)

    Langnau, A.

    1992-01-01

    A thorough investigation of light-cone properties which are characteristic for higher dimensions is very important. The easiest way of addressing these issues is by analyzing the perturbative structure of light-cone field theories first. Perturbative studies cannot be substituted for an analysis of problems related to a nonperturbative approach. However, in order to lay down groundwork for upcoming nonperturbative studies, it is indispensable to validate the renormalization methods at the perturbative level, i.e., to gain control over the perturbative treatment first. A clear understanding of divergences in perturbation theory, as well as their numerical treatment, is a necessary first step towards formulating such a program. The first objective of this dissertation is to clarify this issue, at least in second and fourth-order in perturbation theory. The work in this dissertation can provide guidance for the choice of counterterms in Discrete Light-Cone Quantization or the Tamm-Dancoff approach. A second objective of this work is the study of light-cone perturbation theory as a competitive tool for conducting perturbative Feynman diagram calculations. Feynman perturbation theory has become the most practical tool for computing cross sections in high energy physics and other physical properties of field theory. Although this standard covariant method has been applied to a great range of problems, computations beyond one-loop corrections are very difficult. Because of the algebraic complexity of the Feynman calculations in higher-order perturbation theory, it is desirable to automatize Feynman diagram calculations so that algebraic manipulation programs can carry out almost the entire calculation. This thesis presents a step in this direction. The technique we are elaborating on here is known as light-cone perturbation theory.

  17. Case of Unilateral Peripheral Cone Dysfunction

    Directory of Open Access Journals (Sweden)

    Yujin Mochizuki

    2012-05-01

    Full Text Available Purpose: Peripheral cone dystrophy is a subgroup of cone dystrophy, and only 4 cases have been reported. We present a patient with unilateral peripheral cone dysfunction and report the functional changes determined by electrophysiological tests and ultrastructural changes determined by spectral domain optical coherence tomography (SD-OCT. Case: A 34-year-old woman complained of blurred vision in both eyes. Our examination showed that her visual acuity was 0.05 OD and 0.2 OS. A relative afferent pupillary defect was present in her right eye. The results of slit-lamp examination, ophthalmoscopy, and fluorescein angiography were normal except for pallor of the right optic disc. SD-OCT showed a diffuse thinning of the retina in the posterior pole of the right eye. A severe constriction of the visual fields was found in both eyes but more in the right eye. The photopic full-field electroretinograms (ERGs were reduced in the right eye but normal in the left eye. The multifocal ERGs were severely reduced throughout the visual field except in the central area of the right eye. The multifocal ERGs from the left eye were normal. The pattern visual evoked responses were within the normal range in both eyes. She had a 5-year history of sniffing paint thinner. Results: Although the visual dysfunction was initially suspected to be due to psychological problems from the results of subjective tests, objective tests indicated a peripheral cone dysfunction in the right eye. The pathophysiological mechanism and the relationship with thinner sniffing were not determined. Conclusions: Our findings indicate that peripheral cone dysfunction can occur unilaterally. Electrophysiology and SD-OCT are valuable tests to perform to determine the pathogenesis of unusual ocular findings objectively.

  18. Perturbation theory in light-cone quantization

    International Nuclear Information System (INIS)

    A thorough investigation of light-cone properties which are characteristic for higher dimensions is very important. The easiest way of addressing these issues is by analyzing the perturbative structure of light-cone field theories first. Perturbative studies cannot be substituted for an analysis of problems related to a nonperturbative approach. However, in order to lay down groundwork for upcoming nonperturbative studies, it is indispensable to validate the renormalization methods at the perturbative level, i.e., to gain control over the perturbative treatment first. A clear understanding of divergences in perturbation theory, as well as their numerical treatment, is a necessary first step towards formulating such a program. The first objective of this dissertation is to clarify this issue, at least in second and fourth-order in perturbation theory. The work in this dissertation can provide guidance for the choice of counterterms in Discrete Light-Cone Quantization or the Tamm-Dancoff approach. A second objective of this work is the study of light-cone perturbation theory as a competitive tool for conducting perturbative Feynman diagram calculations. Feynman perturbation theory has become the most practical tool for computing cross sections in high energy physics and other physical properties of field theory. Although this standard covariant method has been applied to a great range of problems, computations beyond one-loop corrections are very difficult. Because of the algebraic complexity of the Feynman calculations in higher-order perturbation theory, it is desirable to automatize Feynman diagram calculations so that algebraic manipulation programs can carry out almost the entire calculation. This thesis presents a step in this direction. The technique we are elaborating on here is known as light-cone perturbation theory

  19. Rod-cone interactions and the temporal impulse response of the cone pathway.

    Science.gov (United States)

    Zele, Andrew J; Cao, Dingcai; Pokorny, Joel

    2008-11-01

    Dark-adapted rods suppress cone-mediated flicker detection. This study evaluates the effect that rod activity has on cone temporal processing by investigating whether rod mediated suppression changes the cone pathway impulse response function, regardless of the form of the temporal signal. Stimuli were generated with a 2-channel photostimulator that has four primaries for the central field and four primaries for the surround. Cone pathway temporal impulse response functions were derived from temporal contrast sensitivity data with periodic stimuli, and from two-pulse discrimination data in which pairs of briefly pulsed stimuli were presented successively at a series of stimulus onset asynchronies. Dark-adapted rods altered the amplitude and timing of cone pathway temporal impulse response functions, irrespective of whether they were derived from measurements with temporally periodic stimuli or in a brief presentation temporal resolution task with pulsed stimuli. Rod-cone interactions are a fundamental operation in visual temporal processing under mesopic light levels, acting to decrease the temporal bandwidth of the visual system. PMID:18486960

  20. A clinical survey of common avian infectious diseases in China.

    Science.gov (United States)

    Zhuang, Qing-Ye; Wang, Su-Chun; Li, Jin-Ping; Liu, Dong; Liu, Shuo; Jiang, Wen-Ming; Chen, Ji-Ming

    2014-06-01

    Multiple common avian infectious diseases (CAIDs), namely, avian infectious diseases excluding highly pathogenic avian influenza and Newcastle disease, such as avian salmonellosis and coccidiosis, cause huge economic loss in poultry production and are of great significance in public health. However, they are usually not covered in the systems for reporting of animal diseases. Consequently, the distribution of CAIDs is not clear in many countries. Here, we report a clinical survey of CAIDs in China based on clinical diagnosis of eight veterinary clinics in 2011 and 2012. This survey provided the distribution data of viral, bacterial, and parasitic CAIDs in different types of avian flocks, seasons, and regions, data that are of great value in the research, prevention, and control of poultry diseases. This survey suggested that avian colibacillosis, infectious serositis in ducks caused by Riemerella anatipestifer, avian salmonellosis, fowl cholera, avian mycoplasmosis, avian aspergillosis, coccidiosis, low pathogenic avian influenza, infectious bronchitis, infectious bursal disease, and infectious laryngotracheitis are likely to be prevalent in the poultry in China. PMID:25055636

  1. Application of inertia cone crushers in heap leaching uranium mines

    International Nuclear Information System (INIS)

    Inertia cone crusher is a high-efficiency, super-fine crushing device with unique principle and structure. The inertia cone crusher has high reduction ratio and low power consumption, and can control final products in narrow scope. It is suitable for crushing uranium ores in heap leaching mines. The particular characters and structure of the inertia cone crusher are briefly introduced. Application of the inertia cone crusher in uranium mines is summarized. It is indicated that the inertia cone crusher has good application prospects in uranium mines. (authors)

  2. Gradient angle estimation by uniform directional simulation on a cone

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager

    1997-01-01

    A sample of uniformly distributed unit vectors on an n-dimensional spherical cone is generated. The distances to a given limit state surface in the directions of the unit vectors of the sample are calculated and each of these distances are projected on the cone axis. The theoretical distribution...... of these projections is derived assuming the limit-state surface to be a hyperplane. This distribution depends on the angle between the cone axis and the normal vector to the hyperplane. Assuming sufficient flatness of the actual limit-state surface within a neighbourhood of the cut point with the cone axis, the cone...

  3. Intracellular calcium stores drive slow non-ribbon vesicle release from rod photoreceptors

    OpenAIRE

    Minghui eChen; David eKrizaj; Thoreson, Wallace B

    2014-01-01

    Rods are capable of greater slow release than cones contributing to overall slower release kinetics. Slow release in rods involves Ca2+-induced Ca2+ release (CICR). By impairing release from ribbons, we found that unlike cones where release occurs entirely at ribbon-style active zones, slow release from rods occurs mostly at ectopic, non-ribbon sites. To investigate the role of CICR in ribbon and non-ribbon release from rods, we used total internal reflection fluorescence microscopy (TIRFM) a...

  4. A range of clinical phenotypes associated with mutations in CRX, a photoreceptor transcription-factor gene.

    OpenAIRE

    Sohocki, M M; Sullivan, L S; Mintz-Hittner, H A; Birch, D.; Heckenlively, J R; Freund, C L; McInnes, R R; Daiger, S P

    1998-01-01

    Mutations in the retinal-expressed gene CRX (cone-rod homeobox gene) have been associated with dominant cone-rod dystrophy and with de novo Leber congenital amaurosis. However, CRX is a transcription factor for several retinal genes, including the opsins and the gene for interphotoreceptor retinoid binding protein. Because loss of CRX function could alter the expression of a number of other retinal proteins, we screened for mutations in the CRX gene in probands with a range of degenerative re...

  5. Differential dimerization of variants linked to enhanced S-Cone Sensitivity Syndrome (ESCS) located in the NR2E3 ligand-binding domain

    Science.gov (United States)

    von Alpen, Désirée; Tran, H. Viet; Guex, Nicolas; Venturini, Giulia; Munier, Francis L.; Schorderet, Daniel F.; Haider, Neena B.; Escher, Pascal

    2016-01-01

    NR2E3 encodes the photoreceptor-specific nuclear hormone receptor that acts as a repressor of cone-specific gene expression in rod photoreceptors, and as an activator of several rod-specific genes. Recessive variants located in the ligand-binding domain (LBD) of NR2E3 cause enhanced short wavelength sensitive- (S-) cone syndrome (ESCS), a retinal degeneration characterized by an excess of Scones and non-functional rods. We analyzed the dimerization properties of NR2E3 and the effect of disease-causing LBD missense variants by bioluminescence resonance energy transfer (BRET2) protein interaction assays. Homodimerization was not affected in presence of p.A256V, p.R039G, p.R311Q and p.R334G variants, but abolished in presence of p.L263P, p.L336P, p.L353V, p.R385P and p.M407K variants. Homology modeling predicted structural changes induced by NR2E3 LBD variants. NR2E3 LBD variants did not affect interaction with CRX, but with NRL and rev-erbα/NR1D1. CRX and NRL heterodimerized more efficiently together, than did either with NR2E3. NR2E3 did not heterodimerize with TLX/NR2E1 and RXRα/NR2C1. The identification of a new compound heterozygous patient with detectable rod function, who expressed solely the p.A256V variant protein, suggests a correlation between LBD variants able to form functional NR2E3 dimers and atypical mild forms of ESCS with residual rod function. PMID:25703721

  6. Morphometric Analysis of the Sternum in Avian Species

    OpenAIRE

    DÜZLER, Ayhan; Özgel, Özcan; DURSUN, Nejdet

    2006-01-01

    The anatomy of the sternum in avian species differs according to their movement and particularly flight capability, as well as species and habitat. Various studies aimed at the examination and measurement of the sternum in avian species have been carried out. However, to the authors' knowledge, no study on the correlation between sternal measurements and movement style has been published previously. In this study, the sternums of certain avian species including the red falcon (Buteo rufi...

  7. Multiple Control Strategies for Prevention of Avian Influenza Pandemic

    OpenAIRE

    Roman Ullah; Gul Zaman; Saeed Islam

    2014-01-01

    We present the prevention of avian influenza pandemic by adjusting multiple control functions in the human-to-human transmittable avian influenza model. First we show the existence of the optimal control problem; then by using both analytical and numerical techniques, we investigate the cost-effective control effects for the prevention of transmission of disease. To do this, we use three control functions, the effort to reduce the number of contacts with human infected with mutant avian influ...

  8. Avian influenza infections in birds – a moving target

    OpenAIRE

    Capua, Ilaria; Alexander, Dennis J.

    2006-01-01

    Avian influenza (AI) is a complex infection of birds, of which the ecology and epidemiology have undergone substantial changes over the last decade. Avian influenza viruses infecting poultry can be divided into two groups. The very virulent viruses cause highly pathogenic avian influenza (HPAI), with flock mortality as high as 100%. These viruses have been restricted to subtypes H5 and H7, although not all H5 and H7 viruses cause HPAI. All other viruses cause a milder, primarily respiratory, ...

  9. Economic effects of avian influenza on egg producers in Turkey

    OpenAIRE

    V Demircan; Yilmaz, H.; Z Dernek; T Bal; Gül, M; H Koknaroglu

    2009-01-01

    This study determined the economic effects of avian influenza on the egg-production sector of Afyon Province, Turkey. Economic indicators were compared before and during the avian influenza outbreak. A questionnaire was conducted with 75 poultry farmers. Farms were divided into three groups according to their size. The profitability of the three farm size groups was compared during two study periods: before and during the avian influenza outbreak. The results indicate that, as compared to pre...

  10. Gluon radiation outside a finite cone

    International Nuclear Information System (INIS)

    The medium-induced gluon radiation angular distributions of light quarks and heavy quarks outside a finite jet cone are studied. We find the effect of destructive interference between the vacuum and medium-induced radiation plays an important role in gluon radiation for very small value of path length L, which leads to the negative value of medium-induced energy loss. The medium-induced radiative energy loss outside an angle for heavy quarks is found to have a minimum and a maximum at small angle for small path length, which are caused by dead cone effect and Brownian k-broadening effect, respectively. However for large path length the minimum and maximum disappear. (author)

  11. Overexpression of retinal degeneration slow (RDS protein adversely affects rods in the rd7 model of enhanced S-cone syndrome.

    Directory of Open Access Journals (Sweden)

    Dibyendu Chakraborty

    Full Text Available The nuclear receptor NR2E3 promotes expression of rod photoreceptor genes while repressing cone genes. Mice lacking NR2E3 (Nr2e3(rd7/rd7 referred to here as rd7 are a model for enhanced S-cone syndrome, a disease associated with increased sensitivity to blue light and night blindness. Rd7 retinas have reduced levels of the outer segment (OS structural protein retinal degeneration slow (RDS. We test the hypothesis that increasing RDS levels would improve the Rd7 phenotype. Transgenic mice over-expressing normal mouse peripherin/RDS (NMP in rods and cones were crossed onto the rd7 background. Disease phenotypes were assessed in NMP/rd7 eyes and compared to wild-type (WT and rd7 eyes at postnatal day 30. NMP/rd7 retinas expressed total RDS (transgenic and endogenous message at WT levels, and NMP protein was correctly localized to the OS. NMP/rd7 retinas have shorter OSs compared to rd7 and WT and significantly reduced number of rosettes. NMP/rd7 mice also exhibited significant deficits in scotopic ERG amplitudes compared to rd7 while photopic amplitudes remained unaffected. Protein levels of rhodopsin, RDS, and the RDS homologue ROM-1 were significantly reduced in the NMP/rd7 retinas compared to rd7. We show that correcting the levels of RDS gene expression does not improve the phenotype of the rd7 suggesting that RDS deficiency is not responsible for the defect in this model. We suggest that the specific rod defect in the NMP/rd7 is likely associated with ongoing problems in the rd7 that are related to the expression of cone genes in rod cells, a characteristic of the model.

  12. Avian influenza virus and free-ranging wild birds

    Science.gov (United States)

    Dierauf, Leslie A.; Karesh, W.B.; Ip, Hon S.; Gilardi, K.V.; Fischer, John R.

    2006-01-01

    Recent media and news reports and other information implicate wild birds in the spread of highly pathogenic avian influenza in Asia and Eastern Europe. Although there is little information concerning highly pathogenic avian influenza viruses in wild birds, scientists have amassed a large amount of data on low-pathogenicity avian influenza viruses during decades of research with wild birds. This knowledge can provide sound guidance to veterinarians, public health professionals, the general public, government agencies, and other entities with concerns about avian influenza.

  13. Avian use of Norris Hill Wind Resource Area, Montana

    Energy Technology Data Exchange (ETDEWEB)

    Harmata, A.; Podruzny, K.; Zelenak, J. [Montana State Univ., Bozeman, MT (United States). Biology Dept.

    1998-07-01

    This document presents results of a study of avian use and mortality in and near a proposed wind resource area in southwestern Montana. Data collected in autumn 1995 through summer 1996 represented preconstruction condition; it was compiled, analyzed, and presented in a format such that comparison with post-construction data would be possible. The primary emphasis of the study was recording avian migration in and near the wind resource area using state-of-the-art marine surveillance radar. Avian use and mortality were investigated during the breeding season by employing traditional avian sampling methods, radiotelemetry, radar, and direct visual observation. 61 figs., 34 tabs.

  14. Hadronic wavefunctions in light-cone quantization

    Energy Technology Data Exchange (ETDEWEB)

    Hyer, T.

    1994-05-01

    The analysis of light-cone wavefunctions seems the most promising theoretical approach to a detailed understanding of the structure of relativistic bound states, particularly hadrons. However, there are numerous complications in this approach. Most importantly, the light-cone approach sacrifices manifest rotational invariance in exchange for the elimination of negative-energy states. The requirement of rotational invariance of the full theory places important constraints on proposed light-cone wavefunctions, whether they are modelled or extracted from some numerical procedure. A formulation of the consequences of the hidden rotational symmetry has been sought for some time; it is presented in Chapter 2. In lattice gauge theory or heavy-quark effective theory, much of the focus is on the extraction of numerical values of operators which are related to the hadronic wavefunction. These operators are to some extent interdependent, with relations induced by fundamental constraints on the underlying wavefunction. The consequences of the requirement of unitarity are explored in Chapter 3, and are found to have startling phenomenological relevance. To test model light-cone wavefunctions, experimental predictions must be made. The reliability of perturbative QCD as a tool for making such predictions has been questioned. In Chapter 4, the author presents a computation of the rates for nucleon-antinucleon annihilation, improving the reliability of the perturbative computation by taking into account the Sudakov suppression of exclusive processes at large transverse impact parameter. In Chapter 5, he develops the analysis of semiexclusive production. This work focuses on processes in which a single isolated meson is produced perturbatively and recoils against a wide hadronizing system. At energies above about 10 GeV, semiexclusive processes are shown to be the most sensitive experimental probes of hadronic structure.

  15. Rod-Cone convergence in the retina.

    OpenAIRE

    Muchungi, Kendi

    2015-01-01

    Vision enables visual perception of one's environs, as well as self-navigation within space. Objects within our environs are visible by virtue of the fact that they re ect light. To see or have visual perception, this light needs to be converted into an electrical signal. This process is referred to as visual transduction and takes place in the retina. Recently, it has become apparent that the convergence of rod and cone systems in transduction is crucial to enable retina fu...

  16. Long polymers near wedges and cones

    Science.gov (United States)

    Hammer, Yosi; Kantor, Yacov

    2015-12-01

    We perform a Monte Carlo study of N -step self-avoiding walks, attached to the corner of an impenetrable wedge in two dimensions (d =2 ), or the tip of an impenetrable cone in d =3 , of sizes ranging up to N =106 steps. We find that the critical exponent γα, which determines the dependence of the number of available conformations on N for a cone or wedge with opening angle α , is in good agreement with the theory for d =2 . We study the end-point distribution of the walks in the allowed space and find similarities to the known behavior of random walks (ideal polymers) in the same geometry. For example, the ratio between the mean square end-to-end distances of a polymer near the cone or wedge and a polymer in free space depends linearly on γα, as is known for ideal polymers. We show that the end-point distribution of polymers attached to a wedge does not separate into a product of angular and radial functions, as it does for ideal polymers in the same geometry. The angular dependence of the end position of polymers near the wedge differs from theoretical predictions.

  17. Long polymers near wedges and cones.

    Science.gov (United States)

    Hammer, Yosi; Kantor, Yacov

    2015-12-01

    We perform a Monte Carlo study of N-step self-avoiding walks, attached to the corner of an impenetrable wedge in two dimensions (d=2), or the tip of an impenetrable cone in d=3, of sizes ranging up to N=10(6) steps. We find that the critical exponent γ(α), which determines the dependence of the number of available conformations on N for a cone or wedge with opening angle α, is in good agreement with the theory for d=2. We study the end-point distribution of the walks in the allowed space and find similarities to the known behavior of random walks (ideal polymers) in the same geometry. For example, the ratio between the mean square end-to-end distances of a polymer near the cone or wedge and a polymer in free space depends linearly on γ(α), as is known for ideal polymers. We show that the end-point distribution of polymers attached to a wedge does not separate into a product of angular and radial functions, as it does for ideal polymers in the same geometry. The angular dependence of the end position of polymers near the wedge differs from theoretical predictions. PMID:26764719

  18. A Coning Theory of Bullet Motions

    CERN Document Server

    Boatright, James A

    2012-01-01

    Each observable ballistic phenomenon of a spin-stabilized rifle bullet can be explained in terms of the acceleration of gravity and the total aerodynamic force acting on that bullet. In addition to the coning motion itself, Coning Theory explains the spinning bullet's aerodynamic jump and its steadily increasing yaw of repose together with its resulting spin-drift. The total aerodynamic force on the bullet comprises its drag and lift rectangular components and produces an associated overturning moment acting upon the rigid bullet. The coning motion of the bullet includes two distinct but synchronized aspects: 1) the well-known gyroscopic precession of the spin-axis of the bullet, and 2) the previously little-known orbiting of the center of gravity of the bullet around its mean trajectory with the nose of the bullet angled inward toward that trajectory. New equations are developed governing the orbital motion of the CG as a circular, isotropic harmonic oscillation driven by the lift and drag forces as they rev...

  19. G-quartet oligonucleotide mediated delivery of proteins into photoreceptors and retinal pigment epithelium via intravitreal injection.

    Science.gov (United States)

    Leaderer, Derek; Cashman, Siobhan M; Kumar-Singh, Rajendra

    2016-04-01

    There is currently no available method to efficiently deliver proteins across the plasma membrane of photoreceptor or retinal pigment epithelium (RPE) cells in vivo. Thus, current clinical application of recombinant proteins in ophthalmology is limited to the use of proteins that perform their biological function extracellularly. The ability to traverse biological membranes would enable the mobilization of a significantly larger number of proteins with previously well characterized properties. Nucleolin is abundantly present on the surface of rapidly dividing cells including cancer cells. Surprisingly, nucleolin is also present on the surface of photoreceptor cell bodies. Here we investigated whether nucleolin can be utilized as a gateway for the delivery of proteins into retinal cells following intravitreal injection. AS1411 is a G-quartet aptamer capable of targeting nucleolin. Subsequent to intravitreal injection, fluorescently labeled AS1411 localized to various retinal cell types including the photoreceptors and RPE. AS1411 linked to streptavidin (a ∼50 kDa protein) via a biotin bridge enabled the uptake of Streptavidin into photoreceptors and RPE. AS1411-Streptavidin conjugate applied topically to the cornea allowed for uptake of the conjugate into the nucleus and cytoplasm of corneal endothelial cells. Clinical relevance of AS1411 as a delivery vehicle was strongly indicated by demonstration of the presence of cell surface nucleolin on the photoreceptors, inner neurons and ganglion cells of human retina. These data support exploration of AS1411 as a means of delivering therapeutic proteins to diseased retina. PMID:26923800

  20. Applications of thermal imaging in avian science

    OpenAIRE

    McCafferty, D. J.

    2013-01-01

    Thermal imaging, or infrared thermography, has been used in avian science since the 1960s. More than 30 species of birds, ranging in size from passerines to ratites, have been studied using this technology. The main strength of this technique is that it is a non-invasive and non-contact method of measuring surface temperature. Its limitations and measurement errors are well understood and suitable protocols have been developed for a variety of experimental settings. Thermal imaging has been u...

  1. Avian influenza and poultry workers, Peru, 2006

    OpenAIRE

    Ortiz, Ernesto J.; Tadeusz J Kochel; Capuano, Ana W; Setterquist, Sharon F.; Gray, Gregory C.

    2007-01-01

    Background  Currently numerous countries in Asia, Africa and Europe are encountering highly pathogenic avian influenza (AI) infections in poultry and humans. In the Americas, home of the world’s largest poultry exporters, contingency plans are being developed and evaluated in preparation for the arrival of these viral strains. Objectives  With this cross‐sectional study, to our knowledge the first in its kind in Central or South America, we sought to learn whether Peruvian poultry workers had...

  2. Prevalence of avian influenza and host ecology

    OpenAIRE

    Garamszegi, László Zsolt; Møller, Anders Pape

    2007-01-01

    Waterfowl and shorebirds are common reservoirs of the low pathogenic subtypes of avian influenza (LPAI), which are easily transmitted to poultry and become highly pathogenic. As the risk of virus transmission depends on the prevalence of LPAI in host-reservoir systems, there is an urgent need for understanding how host ecology, life history and behaviour can affect virus prevalence in the wild. To test for the most important ecological correlates of LPAI virus prevalence at the interspecific ...

  3. Aerosolized avian influenza virus by laboratory manipulations

    OpenAIRE

    Li Zhiping; Li Jinsong; Zhang Yandong; Li Lin; Ma Limin; Li Dan; Gao Feng; Xia Zhiping

    2012-01-01

    Abstract Background Avian H5N1 influenza viruses present a challenge in the laboratory environment, as they are difficult to collect from the air due to their small size and relatively low concentration. In an effort to generate effective methods of H5N1 air removal and ensure the safety of laboratory personnel, this study was designed to investigate the characteristics of aerosolized H5N1 produced by laboratory manipulations during research studies. Results Normal laboratory procedures used ...

  4. Control of Avian Influenza in Poultry

    OpenAIRE

    Capua, Ilaria; Marangon, Stefano

    2006-01-01

    Avian influenza, listed by the World Organization for Animal Health (OIE), has become a disease of great importance for animal and human health. Several aspects of the disease lack scientific information, which has hampered the management of some recent crises. Millions of animals have died, and concern is growing over the loss of human lives and management of the pandemic potential. On the basis of data generated in recent outbreaks and in light of new OIE regulations and maintenance of anim...

  5. Avian influenza: The tip of the iceberg

    OpenAIRE

    Balkhy Hanan

    2008-01-01

    For some years now, we have been living with the fear of an impending pandemic of avian influenza (AI). Despite the recognition, in 1996, of the global threat posed by the highly pathogenic H5N1 influenza virus found in farmed geese in Guangdong Province, China, planning for the anticipated epidemic remains woefully inadequate; this is especially true in developing countries such as Saudi Arabia. These deficiencies became obvious in 1997, with the outbreak of AI in the live animal markets in...

  6. Avian influenza: Myth or mass murder?

    OpenAIRE

    Carol Louie

    2005-01-01

    The purpose of the present article was to determine whether avian influenza (AI) is capable of causing a pandemic. Using research from a variety of medical journals, books and texts, the present paper evaluates the probability of the AI virus becoming sufficiently virulent to pose a global threat. Previous influenza A pandemics from the past century are reviewed, focusing on the mortality rate and the qualities of the virus that distinguish it from other viruses. Each of the influenza A virus...

  7. Evaluation of Antiviral Compounds Against Avian Influenza

    OpenAIRE

    Call, Evan W.

    1991-01-01

    Tests in vitro for antiviral activity against avian influenza viruses, A/Turkey/Sanpete/85 (H6N8) and A/Turkey/Sanpete/86 (H10N9), isolated in Sanpete County, Utah, utilized known antiviral agents, amantadine•HCl (adamantanamine hydrochloride) and ribavirin (1-β-D ribofuranosyl-1,2,4-triazole-3-carboxamide). The testing involved evaluation of seven drug concentrations. Maximum tolerated dose, minimum inhibitory concentration and therapeutic indexes were determined for each drug used. Both dru...

  8. Avian influenza: genetic evolution under vaccination pressure

    OpenAIRE

    Nava Gerardo M; Lucio Eduardo; Rodríguez-Ropón Andrea; Méndez Sara T; Vázquez Lourdes; Escorcia Magdalena

    2008-01-01

    Abstract Antigenic drift of avian influenza viruses (AIVs) has been observed in chickens after extended vaccination program, similar to those observed with human influenza viruses. To evaluate the evolutionary properties of endemic AIV under high vaccination pressure (around 2 billion doses used in the last 12 years), we performed a pilot phylogenic analysis of the hemagglutinin (HA) gene of AIVs isolated from 1994 to 2006. This study demonstrates that Mexican low pathogenicity (LP) H5N2-AIVs...

  9. Avian Influenza: Mixed Infections and Missing Viruses

    OpenAIRE

    Wentworth, David E.; Dugan, Vivien G.; Xudong Lin; Seth Schobel; Magdalena Plancarte; Kelly, Terra R.; Lindsay, LeAnn L.; Boyce, Walter M.

    2013-01-01

    A high prevalence and diversity of avian influenza (AI) viruses were detected in a population of wild mallards sampled during summer 2011 in California, providing an opportunity to compare results obtained before and after virus culture. We tested cloacal swab samples prior to culture by matrix real-time PCR, and by amplifying and sequencing a 640bp portion of the hemagglutinin (HA) gene. Each sample was also inoculated into embryonated chicken eggs, and full genome sequences were determined ...

  10. Avian Coronavirus in Wild Aquatic Birds

    OpenAIRE

    Chu, D. K. W.; Leung, C. Y. H.; Gilbert, M.; Joyner, P. H.; Ng, E. M.; Tse, T. M.; Guan, Y; Peiris, J. S. M.; Poon, L.L.M

    2011-01-01

    We detected a high prevalence (12.5%) of novel avian coronaviruses in aquatic wild birds. Phylogenetic analyses of these coronaviruses suggest that there is a diversity of gammacoronaviruses and deltacoronaviruses circulating in birds. Gammacoronaviruses were found predominantly in Anseriformes birds, whereas deltacoronaviruses could be detected in Ciconiiformes, Pelecaniformes, and Anseriformes birds in this study. We observed that there are frequent interspecies transmissions of gammacorona...

  11. Scaling of avian primary feather length

    OpenAIRE

    Nudds, Robert L.; Kaiser, Gary V.; Dyke, Gareth J.

    2011-01-01

    The evolution of the avian wing has long fascinated biologists, yet almost no work includes the length of primary feathers in consideration of overall wing length variation. Here we show that the length of the longest primary feather ( ) contributing to overall wing length scales with negative allometry against total arm (ta = humerus+ulna+manus). The scaling exponent varied slightly, although not significantly so, depending on whether a species level analysis was used or phylogeny was contro...

  12. Avian cytokines in health and disease

    Directory of Open Access Journals (Sweden)

    Wigley P

    2003-01-01

    Full Text Available Cytokines are proteins secreted by cells that play an important role in the activation and regulation of other cells and tissues during inflammation and immune responses. Although well described in several mammalian species, the role of cytokines and other related proteins is poorly understood in avian species. Recent advances in avian genetics and immunology have begun to allow the exploration of cytokines in health and disease. Cytokines may be classified in a number of ways, but may be conveniently arranged into four broad groups on the basis of their function. Proinflammatory cytokines such as interleukin-6 and interleukin-1beta play a role in mediating inflammation during disease or injury. Th1 cytokines, including interleukin-12 and interferon-gamma, are involved in the induction of cell-mediated immunity, whereas Th2 cytokines such as interleukin-4 are involved in the induction of humoral immunity. The final group Th3 or Tr cytokines play a role in regulation of immunity. The role of various cytokines in infectious and non-infectious diseases of chickens and turkeys is now being investigated. Although there are only a few reliable ELISAs or bioassays developed for avian cytokines, the use of molecular techniques, and in particular quantitative RT-PCR (Taqman has allowed investigation of cytokine responses in a number of diseases including salmonellosis, coccidiosis and autoimmune thyroiditis. In addition the use of recombinant cytokines as therapeutic agents or as vaccine adjuvants is now being explored.

  13. Inhibitory Smads and bone morphogenetic protein (BMP) modulate anterior photoreceptor cell number during planarian eye regeneration.

    Science.gov (United States)

    González-Sastre, Alejandro; Molina, Ma Dolores; Saló, Emili

    2012-01-01

    Planarians represent an excellent model to study the processes of body axis and organ re-specification during regeneration. Previous studies have revealed a conserved role for the bone morphogenetic protein (BMP) pathway and its intracellular mediators Smad1/5/8 and Smad4 in planarian dorsoventral (DV) axis re-establishment. In an attempt to gain further insight into the role of this signalling pathway in planarians, we have isolated and functionally characte-rized the inhibitory Smads (I-Smads) in Schmidtea mediterranea. Two I-Smad homologues have been identified: Smed-smad6/7-1 and Smed-smad6/7-2. Expression of smad6/7-1 was detected in the parenchyma, while smad6/7-2 was found to be ex-pressed in the central nervous system and the eyes. Neither single smad6/7-1 and smad6/7-2 nor double smad6/7-1,-2 silencing gave rise to any apparent disruption of the DV axis. However, both regenerating and intact smad6/7-2 (RNAi) planarians showed defects in eye morphogenesis and displayed small, rounded eyes that lacked the anterior subpopulation of photoreceptor cells. The number of pigment cells was also reduced in these animals at later stages of regeneration. In contrast, after low doses of Smed-bmp(RNAi), planarians regenerated larger eyes in which the anterior subpopulation of photoreceptor cells was expanded. Our results suggest that Smed-smad6/7-2 and Smed-bmp control the re-specification and maintenance of anterior photoreceptor cell number in S. mediterranea. PMID:22451003

  14. Gogo receptor contributes to retinotopic map formation and prevents R1-6 photoreceptor axon bundling.

    Directory of Open Access Journals (Sweden)

    Irina Hein

    Full Text Available BACKGROUND: Topographic maps form the basis of neural processing in sensory systems of both vertebrate and invertebrate species. In the Drosophila visual system, neighboring R1-R6 photoreceptor axons innervate adjacent positions in the first optic ganglion, the lamina, and thereby represent visual space as a continuous map in the brain. The mechanisms responsible for the establishment of retinotopic maps remain incompletely understood. RESULTS: Here, we show that the receptor Golden goal (Gogo is required for R axon lamina targeting and cartridge elongation in a partially redundant fashion with local guidance cues provided by neighboring axons. Loss of function of Gogo in large clones of R axons results in aberrant R1-R6 fascicle spacing. Gogo affects target cartridge selection only indirectly as a consequence of the disordered lamina map. Interestingly, small clones of gogo deficient R axons perfectly integrate into a proper retinotopic map suggesting that surrounding R axons of the same or neighboring fascicles provide complementary spatial guidance. Using single photoreceptor type rescue, we show that Gogo expression exclusively in R8 cells is sufficient to mediate targeting of all photoreceptor types in the lamina. Upon lamina targeting and cartridge selection, R axons elongate within their individual cartridges. Interestingly, here Gogo prevents bundling of extending R1-6 axons. CONCLUSION: Taken together, we propose that Gogo contributes to retinotopic map formation in the Drosophila lamina by controlling the distribution of R1-R6 axon fascicles. In a later developmental step, the regular position of R1-R6 axons along the lamina plexus is crucial for target cartridge selection. During cartridge elongation, Gogo allows R1-R6 axons to extend centrally in the lamina cartridge.

  15. Transcriptomic analysis of human retinal detachment reveals both inflammatory response and photoreceptor death.

    Directory of Open Access Journals (Sweden)

    Marie-Noëlle Delyfer

    Full Text Available BACKGROUND: Retinal detachment often leads to a severe and permanent loss of vision and its therapeutic management remains to this day exclusively surgical. We have used surgical specimens to perform a differential analysis of the transcriptome of human retinal tissues following detachment in order to identify new potential pharmacological targets that could be used in combination with surgery to further improve final outcome. METHODOLOGY/PRINCIPAL FINDINGS: Statistical analysis reveals major involvement of the immune response in the disease. Interestingly, using a novel approach relying on coordinated expression, the interindividual variation was monitored to unravel a second crucial aspect of the pathological process: the death of photoreceptor cells. Within the genes identified, the expression of the major histocompatibility complex I gene HLA-C enables diagnosis of the disease, while PKD2L1 and SLCO4A1 -which are both down-regulated- act synergistically to provide an estimate of the duration of the retinal detachment process. Our analysis thus reveals the two complementary cellular and molecular aspects linked to retinal detachment: an immune response and the degeneration of photoreceptor cells. We also reveal that the human specimens have a higher clinical value as compared to artificial models that point to IL6 and oxidative stress, not implicated in the surgical specimens studied here. CONCLUSIONS/SIGNIFICANCE: This systematic analysis confirmed the occurrence of both neurodegeneration and inflammation during retinal detachment, and further identifies precisely the modification of expression of the different genes implicated in these two phenomena. Our data henceforth give a new insight into the disease process and provide a rationale for therapeutic strategies aimed at limiting inflammation and photoreceptor damage associated with retinal detachment and, in turn, improving visual prognosis after retinal surgery.

  16. Cytochrome P450 2C epoxygenases mediate photochemical stress-induced death of photoreceptors.

    Science.gov (United States)

    Chang, Qing; Berdyshev, Evgeny; Cao, Dingcai; Bogaard, Joseph D; White, Jerry J; Chen, Siquan; Shah, Ravi; Mu, Wenbo; Grantner, Rita; Bettis, Sam; Grassi, Michael A

    2014-03-21

    Degenerative loss of photoreceptors occurs in inherited and age-related retinal degenerative diseases. A chemical screen facilitates development of new testing routes for neuroprotection and mechanistic investigation. Herein, we conducted a mouse-derived photoreceptor (661W cell)-based high throughput screen of the Food and Drug Administration-approved Prestwick drug library to identify putative cytoprotective compounds against light-induced, synthetic visual chromophore-precipitated cell death. Different classes of hit compounds were identified, some of which target known genes or pathways pathologically associated with retinitis pigmentosa. Sulfaphenazole (SFZ), a selective inhibitor of human cytochrome P450 (CYP) 2C9 isozyme, was identified as a novel and leading cytoprotective compound. Expression of CYP2C proteins was induced by light. Gene-targeted knockdown of CYP2C55, the homologous gene of CYP2C9, demonstrated viability rescue to light-induced cell death, whereas stable expression of functional CYP2C9-GFP fusion protein further exacerbated light-induced cell death. Mechanistically, SFZ inhibited light-induced necrosis and mitochondrial stress-initiated apoptosis. Light elicited calcium influx, which was mitigated by SFZ. Light provoked the release of arachidonic acid from membrane phospholipids and production of non-epoxyeicosatrienoic acid metabolites. Administration of SFZ further stimulated the production of non-epoxyeicosatrienoic acid metabolites, suggesting a metabolic shift of arachidonic acid under inhibition of the CYP2C pathway. Together, our findings indicate that CYP2C genes play a direct causative role in photochemical stress-induced death of photoreceptors and suggest that the CYP monooxygenase system is a risk factor for retinal photodamage, especially in individuals with Stargardt disease and age-related macular degeneration that deposit condensation products of retinoids. PMID:24519941

  17. Exploring the active site structure of photoreceptor proteins by Raman optical activity

    Science.gov (United States)

    Unno, Masashi

    2015-03-01

    Understanding protein function at the atomic level is a major challenge in a field of biophysics and requires the combined efforts of structural and functional methods. We use photoreceptor proteins as a model system to understand in atomic detail how a chromophore and a protein interact to sense light and send a biological signal. A potential technique for investigating molecular structures is Raman optical activity (ROA), which is a spectroscopic method with a high sensitivity to the structural details of chiral molecules. However, its application to photoreceptor proteins has not been reported. Thus we have constructed ROA spectrometer using near-infrared (NIR) laser excitation at 785 nm. The NIR excitation enables us to measure ROA spectra for a variety of biological samples, including photoreceptor proteins, without fluorescence from the samples. In the present study, we have applied the NIR-ROA to bacteriorhodopsin (BR) and photoactive yellow protein (PYP). BR is a light-driven proton pump and contains a protonated Schiff base of retinal as a chromophore. PYP is a blue light receptor, and this protein has the 4-hydroxycinnamyl chromophore, which is covalently linked to Cys69 through a thiolester bond. We have successfully obtained the ROA spectra of the chromophore within a protein environment. Furthermore, calculations of the ROA spectra utilizing density functional theory provide detailed structural information, such as data on out-of-plane distortions of the chromophore. The structural information obtained from the ROA spectra includes the positions of hydrogen atoms, which are usually not detected in the crystal structures of biological samples.

  18. Notch1 is required in newly postmitotic cells to inhibit the rod photoreceptor fate

    OpenAIRE

    Mizeracka, Karolina; DeMaso, Christina R.; Cepko, Constance L.

    2013-01-01

    Several models of cell fate determination can be invoked to explain how single retinal progenitor cells (RPCs) produce different cell types in a terminal division. To gain insight into this process, the effects of the removal of a cell fate regulator, Notch1, were studied in newly postmitotic cells using a conditional allele of Notch1 (N1-CKO) in mice. Almost all newly postmitotic N1-CKO cells became rod photoreceptors, whereas wild-type (WT) cells achieved a variety of fates. Single cell pro...

  19. A novel retinal oscillation mechanism in an autosomal dominant photoreceptor degeneration mouse model

    OpenAIRE

    Hung-Ya Tu; Adam Rory McQuiston; Chuan-Chin Chiao; Ching-Kang Chen

    2016-01-01

    It has been shown in rd1 and rd10 models of photoreceptor degeneration (PD) that inner retinal neurons display spontaneous and rhythmic activities. Furthermore, the rhythmic activity has been shown to require the gap junction protein connexin 36, which is likely located in AII amacrine cells (AII-ACs). In the present study, an autosomal dominant PD model called rhoΔCTA, whose rods overexpress a C-terminally truncated mutant rhodopsin and degenerate with a rate similar to that of rd1, was used...

  20. A Novel Retinal Oscillation Mechanism in an Autosomal Dominant Photoreceptor Degeneration Mouse Model

    OpenAIRE

    Tu, Hung-Ya; Chen, Yu-Jiun; McQuiston, Adam R.; Chiao, Chuan-Chin; Chen, Ching-Kang

    2016-01-01

    It has been shown in rd1 and rd10 models of photoreceptor degeneration (PD) that inner retinal neurons display spontaneous and rhythmic activities. Furthermore, the rhythmic activity has been shown to require the gap junction protein connexin 36, which is likely located in AII amacrine cells (AII-ACs). In the present study, an autosomal dominant PD model called rhoΔCTA, whose rods overexpress a C-terminally truncated mutant rhodopsin and degenerate with a rate similar to that of rd1, was used...

  1. Role of Guanylate Cyclase Activating Proteins in photoreceptor cells of the retina in health and disease

    OpenAIRE

    López del Hoyo, Natalia

    2014-01-01

    In the last two decades, it has been done a thoroughly research about the role of Guanylate Cyclase Activating Proteins (GCAPs) in photoreceptor cells of the retina as activity regulators of Retinal Guanylate Cyclase (RetGC), which allow to restore cGMP levels to darkness ones when intracellular Ca2+ falls. However, little is known about: a) ¿What determines GCAPs distribution within the cell?, b) ¿Which other functions GCAP proteins, GCAP1 and GCAP2, carry out at other cellular compartm...

  2. Sensing the light environment in plants: photoreceptors and early signaling steps.

    Science.gov (United States)

    Galvão, Vinicius Costa; Fankhauser, Christian

    2015-10-01

    Plants must constantly adapt to a changing light environment in order to optimize energy conversion through the process of photosynthesis and to limit photodamage. In addition, plants use light cues for timing of key developmental transitions such as initiation of reproduction (transition to flowering). Plants are equipped with a battery of photoreceptors enabling them to sense a very broad light spectrum spanning from UV-B to far-red wavelength (280-750nm). In this review we briefly describe the different families of plant photosensory receptors and the mechanisms by which they transduce environmental information to influence numerous aspects of plant growth and development throughout their life cycle. PMID:25638281

  3. Spectral correlates of a quasi-stable depolarization in barnacle photoreceptor following red light.

    Science.gov (United States)

    Brown, H M; Cornwall, M C

    1975-07-01

    1. Illumination of B. eburneus photoreceptors with intense red light produces a membrane depolarization that persists in darkness. This quasistable depolarization (latch-up) can be terminated with green light. The phenomenon was investigated with electrophysiological, spectrochemical, and microspectrophotometric techniques. 2. Latch-up was associated with a stable inward current in cells with the membrane potential voltage-clamped at the resting potential in darkness. The stable current could only be elicited at wave-lengths greater than 580 nm. 3. Light-induced current (LIC) was measured at various wave-lengths in dark-adapted photoreceptors with the membrane voltage-clamped to the resting potential. The minimum number of photons required to elicit a fixed amount of LIC occurred at 540 nm, indicating that the photoreceptor is maximally sensitive to this wave-length of light. The photoreceptor was also sensitive to wave-lengths in the near-U.V. region of the spectrum (380-420 nm). 4. Steady red adapting light reduced the magnitude of the LIC uniformly at all wave-lengths except in the near-U.V. region of the spectrum; sensitivity was reduced less in this region. 5. The spectrum for termination of the stable inward current following or during red light was shifted to the blue (peak about 510 nm) compared to the peak for LIC (peak about 540 nm). 6. Absorbance of single cells prepared under bright, red light decreased maximally at 480 nm following exposure to wave-lengths of light longer than 540 nm. 7. A pigment extract of 1000 barnacle ocelli prepared under dim, red light had a maximum absorbance change at 480 nm when bleached with blue-gree light. 8. There was no evidence in the latter two experiments of photointerconversion of pigments with absorbance maxima at 480 and 540 nm. Rather, the maximum absorption of the bleaching products seemed to occur at wave-lengths shorter than 420 nm. 9. Since latch-up induction occurs at wave-lengths longer than 580 nm, it may

  4. Correlated evolution of short wavelength sensitive photoreceptor sensitivity and color pattern in Lake Malawi cichlids

    Directory of Open Access Journals (Sweden)

    Michael J. Pauers

    2016-02-01

    Full Text Available For evolutionary ecologists, the holy grail of visual ecology is to establish an unambiguous link between photoreceptor sensitivity, the spectral environment, and the perception of specific visual stimuli (e.g., mates, food, predators, etc.. Due to the bright nuptial colors of the males, and the role female mate choice plays in their evolution, the haplochromine cichlid fishes of the African great lakes are favorite research subjects for such investigations. Despite this attention, current evidence is equivocal; while distinct correlations among photoreceptor sensitivity, photic environment, and male coloration exist in Lake Victorian haplochromines, attempts to find such correlations in Lake Malawian cichlids have failed. Lake Malawi haplochromines have a wide variability in their short-wavelength-sensitive photoreceptors, especially compared to their mid- and long-wavelength-sensitive photoreceptors; these cichlids also vary in the degree to which they express one of three basic color patterns (vertical bars, horizontal stripes, and solid patches of colors, each of which is likely used in a different form of communication. Thus, we hypothesize that, in these fishes, spectral sensitivity and color pattern have evolved in a correlated fashion to maximize visual communication; specifically, ultraviolet sensitivity should be found in vertically-barred species to promote ‘private’ communication, while striped species should be less likely to have ultraviolet sensitivity, since their color pattern carries ‘public’ information. Using phylogenetic independent contrasts, we found that barred species had strong sensitivity to ultraviolet wavelengths, but that striped species typically lacked sensitivity to ultraviolet light. Further, the only variable, even when environmental variables were simultaneously considered, that could predict ultraviolet sensitivity was color pattern. We also found that, using models of correlated evolution, color

  5. Synergetic enhancement of photoconductivity in oxotitanium phthalocyanine nanocrystalline/fluoronone-based azo/BAH composite photoreceptors

    Institute of Scientific and Technical Information of China (English)

    HUANG Ji; SUN Jingzhi; LEI Ying; CHEN Hongzheng; WANG Mang

    2004-01-01

    A simple method of liquid phase direct precipitation (LPDP) is employed to prepare oxotitanium phthalocyanine (TiOPc) nanoparticles. By encapsulation within casein coating, the TiOPc nanoparticles exhibit uniform and well-controlled particle sizes. The results of photoinduced discharge experiment demonstrates that the photoconductivity of the photoreceptors fabricated with TiOPc nanoparticles and fluoronone-based azo pigments as composite carrier generation materials was substantially enhanced. The photosensitivity has been improved three times as the TiOPc particle size decreased from 100 nm to 40 nm.

  6. Intravitreal injection of ciliary neurotrophic factor (CNTF) causes peripheral remodeling and does not prevent photoreceptor loss in canine RPGR mutant retina

    OpenAIRE

    Beltran, William A.; Wen, Rong; Acland, Gregory M.; Aguirre, Gustavo D.

    2007-01-01

    Ciliary neurotrophic factor (CNTF) rescues photoreceptors in several animal models of retinal degeneration and is currently being evaluated as a potential treatment for retinitis pigmentosa in humans. This study was conducted to test whether CNTF prevents photoreceptor cell loss in XLPRA2, an early onset canine model of X-linked retinitis pigmentosa caused by a frameshift mutation in RPGR exon ORF15.

  7. Light-cone Simulations: Evolution of dark matter haloes

    CERN Document Server

    Hein"am"aki, P; Saar, E; Einasto, M; Einasto, J; Virtanen, H; Einasto, Maret; Einasto, Jaan; Virtanen, Heidi

    2005-01-01

    We present a new fast method for simulating pencil-beam type light-cones, using the MLAPM-code (Multi Level Adaptive Particle Mesh) with light-cone additions. We show that by a careful choice of the light-cone orientation, it is possible to avoid extra periodicities in the light-cone. As an example, we apply the method to simulate a 6 Gpc deep light-cone, create the dark matter halo catalogue for the light-cone and study the evolution of haloes from $z=6$ up to the present time. We determine the spatial density of the haloes, their large-scale correlation function, and study the evolution of the mass function. We find a surprisingly simple relation for the dependence of halo maximum mass on redshift, and apply it to derive redshift limits for bright quasars.

  8. Quantum Chromodynamics and Other Field Theories on the Light Cone

    OpenAIRE

    Brodsky, S.; Pauli, H-C; Pinsky, S.

    1997-01-01

    We discuss the light-cone quantization of gauge theories as a calculational tool for representing hadrons as QCD bound-states of relativistic quarks and gluons, and also as a novel method for simulating quantum field theory on a computer. The light-cone Fock state expansion of wavefunctions provides a precise definition of the parton model and a general calculus for hadronic matrix elements. We present several new applications of light-cone Fock methods, including calculations of exclusive we...

  9. Application of inertia cone crushers in Fuzhou uranium mine

    International Nuclear Information System (INIS)

    Inertia cone crusher is a high-efficiency, super-fine crushing equipment with the unique principle and structure. It features high reduction ratio and low power consumption. The final product size can be within the narrow scope. The inertia cone crusher is suitable for crushing uranium ores. The application of the crusher in Fuzhou Uranium Mine is summarized. The result has shown that the inertia cone crusher has good application prospects in percolation leaching circuit of uranium ore. (authors)

  10. Vitreous fluorophotometry in patients with cone-rod dystrophy.

    OpenAIRE

    Miyake, Y; Goto, S.; Ota, I; Ichikawa, H.

    1984-01-01

    Eight patients with cone-rod dystrophy were examined by means of vitreous fluorophotometry. The data in three patients with an early stage of retinitis pigmentosa (rod-cone dystrophy) served for comparison. In contrast with the abnormal findings on vitreous fluorophotometry in patients with an early stage of retinitis pigmentosa the value of vitreous fluorophotometry in cone-rod dystrophy was within the normal range in all patients except the two with advanced stages of this disease. Our resu...

  11. Lateral suppression of mesopic rod and cone flicker detection

    OpenAIRE

    Cao, Dingcai; Lu, Yolanda H.

    2012-01-01

    This study investigated the mechanisms of flicker detection suppression by measuring mesopic rod and cone critical flicker frequencies (CFFs) at different center and surround illuminance levels. Stimuli were generated with a four-primary photostimulator that provided independent control of rod and cone excitations. The results showed that dim surrounds ≤0.2 Td suppressed cone-mediated CFFs at ≥20 Td but not rod-mediated CFFs. These results can be understood in terms of peak amplitudes of phot...

  12. Closed Graph and Open Mapping Theorems for Normed Cones

    Indian Academy of Sciences (India)

    Oscar Valero

    2008-05-01

    A quasi-normed cone is a pair (, ) such that is a (not necessarily cancellative) cone and is a quasi-norm on . The aim of this paper is to prove a closed graph and an open mapping type theorem for quasi-normed cones. This is done with the help of appropriate notions of completeness, continuity and openness that arise in a natural way from the setting of bitopological spaces.

  13. Membrane anchoring subunits specify selective regulation of RGS9·Gβ5 GAP complex in photoreceptor neurons

    OpenAIRE

    Cao, Yan; Kolesnikov, Alexander V.; Masuho, Ikuo; Kefalov, Vladimir J.; Martemyanov, Kirill A.

    2010-01-01

    The RGS9·Gβ5 complex is the key regulator of neuronal G protein signaling that shows remarkable selectivity of subunit composition. In retinal photoreceptors, RGS9·Gβ5 is bound to the membrane anchor R9AP and the complex regulates visual signaling. In the basal ganglia neurons, RGS9·Gβ5 is instead associated with a homologous protein, R7BP, and regulates reward circuit. Switching this selective subunit composition of the complex in rod photoreceptors allowed us to study the molecular underpin...

  14. Avian Influenza Viruses in Water Birds, Africa 1

    OpenAIRE

    Gaidet, Nicolas; Dodman, Tim; Caron, Alexandre; Balança, Gilles; Desvaux, Stephanie; Goutard, Flavie; Cattoli, Giovanni; Lamarque, François; Hagemeijer, Ward; Monicat, François

    2007-01-01

    We report the first large-scale surveillance of avian influenza viruses in water birds conducted in Africa. This study shows evidence of avian influenza viruses in wild birds, both Eurasian and Afro-tropical species, in several major wetlands of Africa.

  15. Genetic differences between avian and human isolates of Candida dubliniensis.

    LENUS (Irish Health Repository)

    McManus, Brenda A

    2009-09-01

    When Candida dubliniensis isolates obtained from seabird excrement and from humans in Ireland were compared by using multilocus sequence typing, 13 of 14 avian isolates were genetically distinct from human isolates. The remaining avian isolate was indistinguishable from a human isolate, suggesting that transmission may occur between humans and birds.

  16. 9 CFR 113.408 - Avian mycoplasma antigen.

    Science.gov (United States)

    2010-01-01

    ... with 9 CFR 114.8. If phenol is used, a direct titration with a standardized bromide-bromate solution... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Avian mycoplasma antigen. 113.408... Diagnostics and Reagents § 113.408 Avian mycoplasma antigen. Mycoplasma antigens shall be prepared...

  17. Molecular cloning and functional characterization of avian interleukin-19

    Science.gov (United States)

    The present study describes the cloning and functional characterization of avian interleukin (IL)-19, a cytokine that, in mammals, alters the balance of Th1 and Th2 cells in favor of the Th2 phenotype. The full-length avian IL-19 gene, located on chromosome 26, was amplified from LPS-stimulated chi...

  18. China's Cool Handling of Avian Flu

    Institute of Scientific and Technical Information of China (English)

    LIWUZHOU

    2004-01-01

    ON January 27, 2004,the China National Avian Flu Reference Lab confirmed that in Dingdang Town, Long'an County,Guangxi Zhuang Autonomous Region a duck had died of the highly pathogenic H5N1 avian influenza. In contrast to the SARS epidemic last year, this occurrence has been handled coolly and efficiently by the Chinese government and people in general.

  19. Practical aspects of vaccination of poultry against avian influenza virus

    Science.gov (United States)

    Although little has changed in vaccine technology for avian influenza virus (AIV) in the past 20 years, the approach to vaccination of poultry (chickens, turkeys and ducks) for avian influenza has evolved as highly pathogenic (HP) AIV has become endemic in several regions of the world. Vaccination f...

  20. THE MOLECULAR BIOLOGY OF AVIAN INFLUENZA VIRUS IN SHORT

    Science.gov (United States)

    Avian influenza virus (AIV) is an important pathogen of poultry as it can cause severe economic losses through disease, including respiratory signs and mortality, and effects on trade. Avian influenza virus is classified as type A influenza, which is a member of the orthomyxoviridae family. Charact...