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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. Action spectra of zebrafish cone photoreceptors.

    Directory of Open Access Journals (Sweden)

    Duco Endeman

    Full Text Available Zebrafish is becoming an increasingly popular model in the field of visual neuroscience. Although the absorption spectra of its cone photopigments have been described, the cone action spectra were still unknown. In this study we report the action spectra of the four types of zebrafish cone photoreceptors, determined by measuring voltage responses upon light stimulation using whole cell patch clamp recordings. A generic template of photopigment absorption spectra was fit to the resulting action spectra in order to establish the maximum absorption wavelength, the A2-based photopigment contribution and the size of the β-wave of each cone-type. Although in general there is close correspondence between zebrafish cone action- and absorbance spectra, our data suggest that in the case of MWS- and LWS-cones there is appreciable contribution of A2-based photopigments and that the β-wave for these cones is smaller than expected based on the absorption spectra.

  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. CNGA3 mutations in hereditary cone photoreceptor disorders

    NARCIS (Netherlands)

    Wissinger, B; Gamer, D; Jagle, H; Giorda, R; Marx, T; Mayer, S; Tippmann, S; Broghammer, M; Jurklies, B; Rosenberg, T; Jacobson, SG; Sener, EC; Tatlipinar, S; Hoyng, CB; Castellan, C; Bitoun, P; Andreasson, S; Rudolph, G; Kellner, U; Lorenz, B; Wolff, G; Verellen-Dumoulin, C; Schwartz, M; Cremers, FPM; Apfelstedt-ylla, E; Zrenner, E; Salati, R; Sharpe, LT; Kohl, S

    2001-01-01

    We recently showed that mutations in the CNGA3 gene encoding the alpha -subunit of the cone photoreceptor cGMP-gated channel cause autosomal recessive complete achromatopsia linked to chromosome 2q11. We now report the results of a first comprehensive screening for CNGA3 mutations in a cohort of 258

  6. Wavelength dependence of reflectometric cone photoreceptor directionality

    NARCIS (Netherlands)

    Zagers, N.P.A.; Berendschot, T.T.J.M.; Norren, D. van

    2003-01-01

    We present evidence for the wavelength dependence of the directionality of light reflected from cone receptor cells (optical StilesCrawford effect): Blue light is more directional than red. According to the waveguide-scattering model of Marcos J. Opt. Soc. Am. A 15 , 2012 (1998), directionality is t

  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. 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

  9. Imaging Ca2+ dynamics in cone photoreceptor axon terminals of the mouse retina.

    Science.gov (United States)

    Kulkarni, Manoj; Schubert, Timm; Baden, Tom; Wissinger, Bernd; Euler, Thomas; Paquet-Durand, Francois

    2015-01-01

    Retinal cone photoreceptors (cones) serve daylight vision and are the basis of color discrimination. They are subject to degeneration, often leading to blindness in many retinal diseases. Calcium (Ca(2+)), a key second messenger in photoreceptor signaling and metabolism, has been proposed to be indirectly linked with photoreceptor degeneration in various animal models. Systematically studying these aspects of cone physiology and pathophysiology has been hampered by the difficulties of electrically recording from these small cells, in particular in the mouse where the retina is dominated by rod photoreceptors. To circumvent this issue, we established a two-photon Ca(2+) imaging protocol using a transgenic mouse line that expresses the genetically encoded Ca(2+) biosensor TN-XL exclusively in cones and can be crossbred with mouse models for photoreceptor degeneration. The protocol described here involves preparing vertical sections ("slices") of retinas from mice and optical imaging of light stimulus-evoked changes in cone Ca(2+) level. The protocol also allows "in-slice measurement" of absolute Ca(2+) concentrations; as the recordings can be followed by calibration. This protocol enables studies into functional cone properties and is expected to contribute to the understanding of cone Ca(2+) signaling as well as the potential involvement of Ca(2+) in photoreceptor death and retinal degeneration. PMID:25993489

  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. A positive feedback synapse from retinal horizontal cells to cone photoreceptors.

    Directory of Open Access Journals (Sweden)

    Skyler L Jackman

    2011-05-01

    Full Text Available Cone photoreceptors and horizontal cells (HCs have a reciprocal synapse that underlies lateral inhibition and establishes the antagonistic center-surround organization of the visual system. Cones transmit to HCs through an excitatory synapse and HCs feed back to cones through an inhibitory synapse. Here we report that HCs also transmit to cone terminals a positive feedback signal that elevates intracellular Ca(2+ and accelerates neurotransmitter release. Positive and negative feedback are both initiated by AMPA receptors on HCs, but positive feedback appears to be mediated by a change in HC Ca(2+, whereas negative feedback is mediated by a change in HC membrane potential. Local uncaging of AMPA receptor agonists suggests that positive feedback is spatially constrained to active HC-cone synapses, whereas the negative feedback signal spreads through HCs to affect release from surrounding cones. By locally offsetting the effects of negative feedback, positive feedback may amplify photoreceptor synaptic release without sacrificing HC-mediated contrast enhancement.

  13. 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...

  14. 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...

  15. Multiple rod-cone and cone-rod photoreceptor transmutations in snakes: evidence from visual opsin gene expression.

    Science.gov (United States)

    Simões, 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

    2016-01-27

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  17. 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  19. LINC complexes mediate the positioning of cone photoreceptor nuclei in mouse retina.

    Directory of Open Access Journals (Sweden)

    David Razafsky

    Full Text Available It has long been observed that many neuronal types position their nuclei within restricted cytoplasmic boundaries. A striking example is the apical localization of cone photoreceptors nuclei at the outer edge of the outer nuclear layer of mammalian retinas. Yet, little is known about how such nuclear spatial confinement is achieved and further maintained. Linkers of the Nucleoskeleton to the Cytoskeleton (LINC complexes consist of evolutionary-conserved macromolecular assemblies that span the nuclear envelope to connect the nucleus with the peripheral cytoskeleton. Here, we applied a new transgenic strategy to disrupt LINC complexes either in cones or rods. In adult cones, we observed a drastic nuclear mislocalization on the basal side of the ONL that affected cone terminals overall architecture. We further provide evidence that this phenotype may stem from the inability of cone precursor nuclei to migrate towards the apical side of the outer nuclear layer during early postnatal retinal development. By contrast, disruption of LINC complexes within rod photoreceptors, whose nuclei are scattered across the outer nuclear layer, had no effect on the positioning of their nuclei thereby emphasizing differential requirements for LINC complexes by different neuronal types. We further show that Sun1, a component of LINC complexes, but not A-type lamins, which interact with LINC complexes at the nuclear envelope, participate in cone nuclei positioning. This study provides key mechanistic aspects underlying the well-known spatial confinement of cone nuclei as well as a new mouse model to evaluate the pathological relevance of nuclear mispositioning.

  20. Differentiation of human embryonic stem cells into cone photoreceptors through simultaneous inhibition of BMP, TGFβ and Wnt signaling.

    Science.gov (United States)

    Zhou, Shufeng; Flamier, Anthony; Abdouh, Mohamed; Tétreault, Nicolas; Barabino, Andrea; Wadhwa, Shashi; Bernier, Gilbert

    2015-10-01

    Cone photoreceptors are required for color discrimination and high-resolution central vision and are lost in macular degenerations, cone and cone/rod dystrophies. Cone transplantation could represent a therapeutic solution. However, an abundant source of human cones remains difficult to obtain. Work performed in model organisms suggests that anterior neural cell fate is induced 'by default' if BMP, TGFβ and Wnt activities are blocked, and that photoreceptor genesis operates through an S-cone default pathway. We report here that Coco (Dand5), a member of the Cerberus gene family, is expressed in the developing and adult mouse retina. Upon exposure to recombinant COCO, human embryonic stem cells (hESCs) differentiated into S-cone photoreceptors, developed an inner segment-like protrusion, and could degrade cGMP when exposed to light. Addition of thyroid hormone resulted in a transition from a unique S-cone population toward a mixed M/S-cone population. When cultured at confluence for a prolonged period of time, COCO-exposed hESCs spontaneously developed into a cellular sheet composed of polarized cone photoreceptors. COCO showed dose-dependent and synergistic activity with IGF1 at blocking BMP/TGFβ/Wnt signaling, while its cone-inducing activity was blocked in a dose-dependent manner by exposure to BMP, TGFβ or Wnt-related proteins. Our work thus provides a unique platform to produce human cones for developmental, biochemical and therapeutic studies and supports the hypothesis that photoreceptor differentiation operates through an S-cone default pathway during human retinal development. PMID:26443633

  1. 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.

  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.

  3. 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

  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. Nuclear kinesis, neurite sprouting and abnormal axonal projections of cone photoreceptors in the aged and AMD-afflicted human retina.

    Science.gov (United States)

    Pow, David V; Sullivan, Robert K P

    2007-05-01

    Tissues often respond to damage by recapitulating developmental programs. We have investigated whether anatomical signs of developmental recapitulation are evident in cone photoreceptors of the aged and AMD-afflicted human retina. Radial migration of cell nuclei mediated by microtubules is a characteristic feature of cells in the developing retina. Similarly, neurite outgrowth is a feature of developing neurons. We have examined whether nuclear kinesis and neurite outgrowth from cone photoreceptors is evident. Calbindin-positive cone photoreceptor nuclei are normally positioned as a single layer of somata at the outer border of the outer nuclear layer. In AMD-afflicted retinae, many nuclei are translocated, with some somata abutting the outer plexiform layer (OPL) and others outside the outer limiting membrane whilst many nuclei are present at intermediate levels. The axonal processes of many cones were also aberrant, displaying tortuous pathways as they projected to the OPL, with occasional evidence for bifurcation at points where the axon changed direction. We suggest that tangential extension of collateral neurites and the rapid retraction of the original process may give rise to the tortuous axonal projections observed. Since microtubules are key mediators of both neurite extension and nuclear kinesis we examined expression of microtubule associated protein 2 (MAP2) which is an important regulator of neurite extension. The strong expression of MAP2 observed in those cells with aberrant morphologies supports the notion that abnormal microtubule-mediated remodelling events are present in the AMD retina and to a lesser extent in normal aged retinas, allowing cone photoreceptors to recapitulate two key features of development.

  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. 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

  9. miRNAs 182 and 183 are necessary to maintain adult cone photoreceptor outer segments and visual function.

    Science.gov (United States)

    Busskamp, Volker; Krol, Jacek; Nelidova, Dasha; Daum, Janine; Szikra, Tamas; Tsuda, Ben; Jüttner, Josephine; Farrow, Karl; Scherf, Brigitte Gross; Alvarez, Claudia Patricia Patino; Genoud, Christel; Sothilingam, Vithiyanjali; Tanimoto, Naoyuki; Stadler, Michael; Seeliger, Mathias; Stoffel, Markus; Filipowicz, Witold; Roska, Botond

    2014-08-01

    The outer segments of cones serve as light detectors for daylight color vision, and their dysfunction leads to human blindness conditions. We show that the cone-specific disruption of DGCR8 in adult mice led to the loss of miRNAs and the loss of outer segments, resulting in photoreceptors with significantly reduced light responses. However, the number of cones remained unchanged. The loss of the outer segments occurred gradually over 1 month, and during this time the genetic signature of cones decreased. Reexpression of the sensory-cell-specific miR-182 and miR-183 prevented outer segment loss. These miRNAs were also necessary and sufficient for the formation of inner segments, connecting cilia and short outer segments, as well as light responses in stem-cell-derived retinal cultures. Our results show that miR-182- and miR-183-regulated pathways are necessary for cone outer segment maintenance in vivo and functional outer segment formation in vitro. PMID:25002228

  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. Cone photoreceptor sensitivities and unique hue chromatic responses: correlation and causation imply the physiological basis of unique hues.

    Directory of Open Access Journals (Sweden)

    Ralph W Pridmore

    Full Text Available This paper relates major functions at the start and end of the color vision process. The process starts with three cone photoreceptors transducing light into electrical responses. Cone sensitivities were once expected to be Red Green Blue color matching functions (to mix colors but microspectrometry proved otherwise: they instead peak in yellowish, greenish, and blueish hues. These physiological functions are an enigma, unmatched with any set of psychophysical (behavioral functions. The end-result of the visual process is color sensation, whose essential percepts are unique (or pure hues red, yellow, green, blue. Unique hues cannot be described by other hues, but can describe all other hues, e.g., that hue is reddish-blue. They are carried by four opponent chromatic response curves but the literature does not specify whether each curve represents a range of hues or only one hue (a unique over its wavelength range. Here the latter is demonstrated, confirming that opponent chromatic responses define, and may be termed, unique hue chromatic responses. These psychophysical functions also are an enigma, unmatched with any physiological functions or basis. Here both enigmas are solved by demonstrating the three cone sensitivity curves and the three spectral chromatic response curves are almost identical sets (Pearson correlation coefficients r from 0.95-1.0 in peak wavelengths, curve shapes, math functions, and curve crossover wavelengths, though previously unrecognized due to presentation of curves in different formats, e.g., log, linear. (Red chromatic response curve is largely nonspectral and thus derives from two cones. Close correlation combined with deterministic causation implies cones are the physiological basis of unique hues. This match of three physiological and three psychophysical functions is unique in color vision.

  12. Avian ultraviolet/violet cones identified as probable magnetoreceptors.

    Directory of Open Access Journals (Sweden)

    Christine Niessner

    Full Text Available BACKGROUND: The Radical-Pair-Model postulates that the reception of magnetic compass directions in birds is based on spin-chemical reactions in specialized photopigments in the eye, with cryptochromes discussed as candidate molecules. But so far, the exact subcellular characterization of these molecules in the retina remained unknown. METHODOLOGY/PRINCIPAL FINDINGS: We here describe the localization of cryptochrome 1a (Cry1a in the retina of European robins, Erithacus rubecula, and domestic chickens, Gallus gallus, two species that have been shown to use the magnetic field for compass orientation. In both species, Cry1a is present exclusively in the ultraviolet/violet (UV/V cones that are distributed across the entire retina. Electron microscopy shows Cry1a in ordered bands along the membrane discs of the outer segment, and cell fractionation reveals Cry1a in the membrane fraction, suggesting the possibility that Cry1a is anchored along membranes. CONCLUSIONS/SIGNIFICANCE: We provide first structural evidence that Cry1a occurs within a sensory structure arranged in a way that fulfils essential requirements of the Radical-Pair-Model. Our findings, identifying the UV/V-cones as probable magnetoreceptors, support the assumption that Cry1a is indeed the receptor molecule mediating information on magnetic directions, and thus provide the Radical-Pair-Model with a profound histological background.

  13. 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

  14. Distribution of retinal cone photoreceptor oil droplets, and identification of associated carotenoids in crow (Corvus macrorhynchos).

    Science.gov (United States)

    Rahman, Mohammad Lutfur; Yoshida, Kazuyuki; Maeda, Isamu; Tanaka, Hideuki; Sugita, Shoei

    2010-06-01

    The topography of cone oil droplets and their carotenoids were investigated in the retina of jungle crow (Corvus macrorhynchos). Fresh retina was sampled for the study of retinal cone oil droplets, and extracted retinal carotenoids were saponified using methods adapted from a recent study, then identified with reverse-phase high-performance liquid chromatography (HPLC). To assess the effects of saponification conditions on carotenoid recovery from crow retina, we varied base concentration and total time of saponification across a wide range of conditions, and again used HPLC to compare carotenoid concentrations. Based on colors, at least four types of oil droplets were recognized, i.e., red, orange, green, and translucent, across the retina. With an average of 91,202 /mm(2), density gradually declines in an eccentric manner from optic disc. In retina, the density and size of droplets are inversely related. In the peripheral zone, oil droplets were significantly larger than those of the central area. The proportion of orange oil droplets (33%) was higher in the central area, whereas green was predominant in other areas. Three types of carotenoid (astaxanthin, galloxanthin and lutein), together with one unknown carotenoid, were recovered from the crow retina; astaxanthin was the dominant carotenoid among them. The recovery of carotenoids was affected by saponification conditions. Astaxanthin was well recovered in weak alkali (0.06 M KOH), in contrast, xanthophyllic carotenoids were best recovered in strong alkali (0.6 M KOH) after 12 h of saponification at freeze temperature.

  15. 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 ...

  16. 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...

  17. Clinical characteristics of rod and cone photoreceptor dystrophies in patients with mutations in the C8orf37 gene

    NARCIS (Netherlands)

    Huet, R.A.C. van; Estrada-Cuzcano, A.; Banin, E.; Rotenstreich, Y.; Hipp, S.; Kohl, S.; Hoyng, C.B.; Hollander, A.I. den; Collin, R.W.J.; Klevering, B.J.

    2013-01-01

    PURPOSE: To provide the clinical features in patients with retinal disease caused by C8orf37 gene mutations. METHODS: Eight patients--four diagnosed with retinitis pigmentosa (RP) and four with cone-rod dystrophy (CRD), carrying causal C8orf37 mutations--were clinically evaluated, including extensiv

  18. 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...

  19. 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...

  20. 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...

  1. 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.

  2. 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...

  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. 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

  5. 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 .

  6. 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 ...

  7. 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

  8. 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.

  9. p53 selectively regulates developmental apoptosis of rod photoreceptors.

    Directory of Open Access Journals (Sweden)

    Linda Vuong

    Full Text Available Retinal cells become post-mitotic early during post-natal development. It is likely that p53, a well-known cell cycle regulator, is involved in regulating the genesis, differentiation and death of retinal cells. Furthermore, retinal cells are under constant oxidative stress that can result in DNA damage, due to the extremely high level of metabolic activity associated with phototransduction. If not repaired, this damage may result in p53-dependent cell death and ensuing vision loss. In this study, the role of p53 during retinal development and in the post-mitotic retina is investigated. A previously described super p53 transgenic mouse that expresses an extra copy of the mouse p53 gene driven by its endogenous promoter is utilized. Another transgenic mouse (HIP that expresses the p53 gene in rod and cone photoreceptors driven by the human interphotoreceptor retinoid binding protein promoter was generated. The electroretinogram (ERG of the super p53 mouse exhibited reduced rod-driven scotopic a and b wave and cone-driven photopic b wave responses. This deficit resulted from a reduced number of rod photoreceptors and inner nuclear layer cells. However, the reduced photopic signal arose only from lost inner retinal neurons, as cone numbers did not change. Furthermore, cell loss was non-progressive and resulted from increased apoptosis during retinal developmental as determined by TUNEL staining. In contrast, the continuous and specific expression of p53 in rod and cone photoreceptors in the mature retinas of HIP mice led to the selective loss of both rods and cones. These findings strongly support a role for p53 in regulating developmental apoptosis in the retina and suggest a potential role, either direct or indirect, for p53 in the degenerative photoreceptor loss associated with human blinding disorders.

  10. 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.

  11. 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...

  12. Loss of Pde6 reduces cell body Ca(2+) transients within photoreceptors.

    Science.gov (United States)

    Ma, E Y; Lewis, A; Barabas, P; Stearns, G; Suzuki, S; Krizaj, D; Brockerhoff, S E

    2013-01-01

    Modulation of Ca(2+) within cells is tightly regulated through complex and dynamic interactions between the plasma membrane and internal compartments. In this study, we exploit in vivo imaging strategies based on genetically encoded Ca(2+) indicators to define changes in perikaryal Ca(2+) concentration of intact photoreceptors. We developed double-transgenic zebrafish larvae expressing GCaMP3 in all cones and tdTomato in long-wavelength cones to test the hypothesis that photoreceptor degeneration induced by mutations in the phosphodiesterase-6 (Pde6) gene is driven by excessive [Ca(2+)]i levels within the cell body. Arguing against Ca(2+) overload in Pde6 mutant photoreceptors, simultaneous analysis of cone photoreceptor morphology and Ca(2+) fluxes revealed that degeneration of pde6c(w59) mutant cones, which lack the cone-specific cGMP phosphodiesterase, is not associated with sustained increases in perikaryal [Ca(2+)]i. Analysis of [Ca(2+)]i in dissociated Pde6β(rd1)mouse rods shows conservation of this finding across vertebrates. In vivo, transient and Pde6-independent Ca(2+) elevations ('flashes') were detected throughout the inner segment and the synapse. As the mutant cells proceeded to degenerate, these Ca(2+) fluxes diminished. This study thus provides insight into Ca(2+) dynamics in a common form of inherited blindness and uncovers a dramatic, light-independent modulation of [Ca(2+)]i that occurs in normal cones. PMID:24030149

  13. Loss of Pde6 reduces cell body Ca2+ transients within photoreceptors

    Science.gov (United States)

    Ma, E Y; Lewis, A; Barabas, P; Stearns, G; Suzuki, S; Krizaj, D; Brockerhoff, S E

    2013-01-01

    Modulation of Ca2+ within cells is tightly regulated through complex and dynamic interactions between the plasma membrane and internal compartments. In this study, we exploit in vivo imaging strategies based on genetically encoded Ca2+ indicators to define changes in perikaryal Ca2+ concentration of intact photoreceptors. We developed double-transgenic zebrafish larvae expressing GCaMP3 in all cones and tdTomato in long-wavelength cones to test the hypothesis that photoreceptor degeneration induced by mutations in the phosphodiesterase-6 (Pde6) gene is driven by excessive [Ca2+]i levels within the cell body. Arguing against Ca2+ overload in Pde6 mutant photoreceptors, simultaneous analysis of cone photoreceptor morphology and Ca2+ fluxes revealed that degeneration of pde6cw59 mutant cones, which lack the cone-specific cGMP phosphodiesterase, is not associated with sustained increases in perikaryal [Ca2+]i. Analysis of [Ca2+]i in dissociated Pde6βrd1mouse rods shows conservation of this finding across vertebrates. In vivo, transient and Pde6-independent Ca2+ elevations (‘flashes') were detected throughout the inner segment and the synapse. As the mutant cells proceeded to degenerate, these Ca2+ fluxes diminished. This study thus provides insight into Ca2+ dynamics in a common form of inherited blindness and uncovers a dramatic, light-independent modulation of [Ca2+]i that occurs in normal cones. PMID:24030149

  14. Reorganization of human cortical maps caused by inherited photoreceptor abnormalities.

    Science.gov (United States)

    Baseler, Heidi A; Brewer, Alyssa A; Sharpe, Lindsay T; Morland, Antony B; Jägle, Herbert; Wandell, Brian A

    2002-04-01

    We describe a compelling demonstration of large-scale developmental reorganization in the human visual pathways. The developmental reorganization was observed in rod monochromats, a rare group of congenitally colorblind individuals who virtually lack cone photoreceptor function. Normal controls had a cortical region, spanning several square centimeters, that responded to signals initiated in the all-cone foveola but was inactive under rod viewing conditions; in rod monochromats this cortical region responded powerfully to rod-initiated signals. The measurements trace a causal pathway that begins with a genetic anomaly that directly influences sensory cells and ultimately results in a substantial central reorganization. PMID:11914722

  15. 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

  16. Photoreceptor Impairment and Restoration on Optical Coherence Tomographic Image

    Directory of Open Access Journals (Sweden)

    Yoshinori Mitamura

    2013-01-01

    Full Text Available With recent development of spectral-domain optical coherence tomography (SD-OCT, the pathological changes of retina can be observed in much greater detail. SD-OCT clearly delineates three highly reflective lines in the outer retina, which are external limiting membrane (ELM, photoreceptor inner and outer segment (IS/OS junction, and cone outer segment tips (COST in order from inside. These lines can serve as hallmarks for the evaluation of photoreceptor condition. In retinitis pigmentosa (RP leading to photoreceptor degeneration, the ELM, IS/OS, and COST lines are shortened with the progression of the disease. In addition, shortening of the ELM, IS/OS and COST lines is significantly associated with each other. The line length is longest in the ELM, followed by the IS/OS, and COST, suggesting that retinal layer becomes disorganized first at the COST, followed by the IS/OS and finally the ELM. This finding is consistent with the previous report that the earliest histopathological change in RP is a shortening of the photoreceptor outer segments. On the other hand, retinal layer becomes restored first at the ELM, followed by the IS/OS and finally the COST after macular hole surgery. There may be a directionality of photoreceptor impairment or restoration on optical coherence tomographic image.

  17. Vision. Realignment of cones after cataract removal.

    Science.gov (United States)

    Smallman, H S; MacLeod, D I; Doyle, P

    2001-08-01

    Through unique observations of an adult case of bilateral congenital cataract removal, we have found evidence that retinal photoreceptors will swiftly realign towards the brightest regions in the pupils of the eye. Cones may be phototropic, actively orientating themselves towards light like sunflowers in a field.

  18. 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.

  19. 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

  20. 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.

  1. 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...

  2. Cone rod dystrophies.

    Science.gov (United States)

    Hamel, Christian P

    2007-01-01

    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 always advised. Currently

  3. Bifurcation analysis of a photoreceptor interaction model for Retinitis Pigmentosa

    Science.gov (United States)

    Camacho, Erika T.; Radulescu, Anca; Wirkus, Stephen

    2016-09-01

    Retinitis Pigmentosa (RP) is the term used to describe a diverse set of degenerative eye diseases affecting the photoreceptors (rods and cones) in the retina. This work builds on an existing mathematical model of RP that focused on the interaction of the rods and cones. We non-dimensionalize the model and examine the stability of the equilibria. We then numerically investigate other stable modes that are present in the system for various parameter values and relate these modes to the original problem. Our results show that stable modes exist for a wider range of parameter values than the stability of the equilibrium solutions alone, suggesting that additional approaches to preventing cone death may exist.

  4. 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 ...

  5. 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

  6. 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.

  7. 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 ...

  8. Clinical course of cone dystrophy caused by mutations in the RPGR gene

    NARCIS (Netherlands)

    Thiadens, A.A.H.J.; Soerjoesing, G.G.; Florijn, R.J.; Tjiam, A.G.; Hollander, A.I. den; Born, L.I. van den; Riemslag, F.C.; Bergen, A.A.B.; Klaver, C.C.

    2011-01-01

    BACKGROUND: Mutations in the RPGR gene predominantly cause rod photoreceptor disorders with a large variability in clinical course. In this report, we describe two families with mutations in this gene and cone involvement. METHODS: We investigated an X-linked cone dystrophy family (1) with 25 affect

  9. 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

  10. 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.

  11. Modeling the role of mid-wavelength cones in circadian responses to light.

    Science.gov (United States)

    Dkhissi-Benyahya, Ouria; Gronfier, Claude; De Vanssay, Wena; Flamant, Frederic; Cooper, Howard M

    2007-03-01

    Nonvisual responses to light, such as photic entrainment of the circadian clock, involve intrinsically light-sensitive melanopsin-expressing ganglion cells as well as rod and cone photoreceptors. However, previous studies have been unable to demonstrate a specific contribution of cones in the photic control of circadian responses to light. Using a mouse model that specifically lacks mid-wavelength (MW) cones we show that these photoreceptors play a significant role in light entrainment and in phase shifting of the circadian oscillator. The contribution of MW cones is mainly observed for light exposures of short duration and toward the longer wavelength region of the spectrum, consistent with the known properties of this opsin. Modeling the contributions of the various photoreceptors stresses the importance of considering the particular spectral, temporal, and irradiance response domains of the photopigments when assessing their role and contribution in circadian responses to light.

  12. 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 ...

  13. 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.

  14. 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...

  15. On Dispersion in Visual Photoreceptors

    NARCIS (Netherlands)

    Stavenga, D.G.; Barneveld, H.H. van

    1975-01-01

    An idealized visual pigment absorbance spectrum is used together with a Kramers-Kronig dispersion relation to calculate the contribution of the visual pigment to the refractive index of the fly photoreceptor. It appears that an absorption coefficient of 0.010 µm-1 results in a refractive index varia

  16. Peripheral detection and resolution with mid-/long-wavelength and short-wavelength sensitive cone systems.

    Science.gov (United States)

    Zhu, Hai-Feng; Zele, Andrew J; Suheimat, Marwan; Lambert, Andrew J; Atchison, David A

    2016-08-01

    This study compared neural resolution and detection limits of the human mid-/long-wavelength and short-wavelength cone systems with anatomical estimates of photoreceptor and retinal ganglion cell spacings and sizes. Detection and resolution limits were measured from central fixation out to 35° eccentricity across the horizontal visual field using a modified Lotmar interferometer. The mid-/long-wavelength cone system was studied using a green (550 nm) test stimulus to which S-cones have low sensitivity. To bias resolution and detection to the short-wavelength cone system, a blue (450 nm) test stimulus was presented against a bright yellow background that desensitized the M- and L-cones. Participants were three trichromatic males with normal visual functions. With green stimuli, resolution showed a steep central-peripheral gradient that was similar between participants, whereas the detection gradient was shallower and patterns were different between participants. Detection and resolution with blue stimuli were poorer than for green stimuli. The detection of blue stimuli was superior to resolution across the horizontal visual field and the patterns were different between participants. The mid-/long-wavelength cone system's resolution is limited by midget ganglion cell spacing and its detection is limited by the size of the M- and L-cone photoreceptors, consistent with previous observations. We found that no such simple relationships occur for the short-wavelength cone system between resolution and the bistratified ganglion cell spacing, nor between detection and the S-cone photoreceptor sizes.

  17. 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.

  18. 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

  19. Avian influenza

    Science.gov (United States)

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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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

  8. Double Cones as a Basis for Polarization Sensitivity in Vertebrates

    Science.gov (United States)

    Rowe, Manoel

    1995-01-01

    Over the course of the past 50 years there has been an increasing number of claims that certain vertebrates are sensitive to the linear polarization state of visible radiation. However, the mechanism(s) that mediates this polarization sensitivity remains elusive at the present time. The retinas of most vertebrates contain anatomical structures loosely referred to as double cones--composite entities constituted by the apposition of two independently developed, diurnally active photoreceptors. The significance of this apposition for visual function also remains elusive. It is possible that double cones mediate polarization sensitivity as a consequence of geometric birefringence; light polarized parallel to the axis joining the centers of the two halves of a double cone can potentially stimulate the receptors more strongly than light polarized in the direction perpendicular to both that axis and the normal axis of light propagation down the length of the double cone. The feasibility of this mechanism for polarization sensitivity has been examined here with specific reference to the retina of a representative animal, the green sunfish (Lepomis cyanellus). Transmission electron micrographs of thin sections from a sunfish retina were analyzed in order to develop simple models of waveguiding down the long axis of a sunfish double cone. The results of the computations indicate that the mechanism is feasible only if there are refractive index gradients in the photoreceptors of sunfish. Isolated receptors were thus examined with scanning microinterferometry to demonstrate the presence of such gradients. In the course of the investigation, the literature pertaining to vertebrate polarization sensitivity and retinal anatomy were reviewed to delimit the generality of the conclusions drawn from sunfish photoreceptors. As a result of this analysis, it should be concluded that much future research is needed to clarify what (if any) role optical polarization plays in the sensory

  9. 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...

  10. 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...

  11. 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,

  12. 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,

  13. Cobalt ions enhance light responsiveness of carp cone horizontal cells in low calcium

    Institute of Scientific and Technical Information of China (English)

    王海龙; 杨雄里

    1996-01-01

    Effects of cobalt ions (Co2+) on horizontal cells in low extracellular calcium were examined in isolated, superfused carp retinas. While 0.1mmol/L Co2+ completely suppressed both rod- and cone-driven horizontal cells in normal Ringer’s solution, it enhanced light responses of cone horizontal cells in low (0.1mmol/L) calcium. The enhancement of the cone horizontal cell response by Co2+ was not caused by changes in light responsiveness of cone photoreceptors. Moreover, application of 50μmol/L IBMX, an inhibitor of phosphodiester enzyme, reduced the suppressive effect of 0.1 mmol/L Co2+ in normal Ringer’s solution. In consequence, the above-described enhancement of the cone horizontal cell light responsiveness may be due to a depolarization of cones caused by low calcium, which increases the activity of voltage-dependent calcium channels at cone terminals.

  14. 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

  15. 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

  16. 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

  17. Role of spectraplakin in Drosophila photoreceptor morphogenesis.

    Directory of Open Access Journals (Sweden)

    Uyen Ngoc Mui

    Full Text Available BACKGROUND: Crumbs (Crb, a cell polarity gene, has been shown to provide a positional cue for the apical membrane domain and adherens junction during Drosophila photoreceptor morphogenesis. It has recently been found that stable microtubules in developing Drosophila photoreceptors were linked to Crb localization. Coordinated interactions between microtubule and actin cytoskeletons are involved in many polarized cellular processes. Since Spectraplakin is able to bind both microtubule and actin cytoskeletons, the role of Spectraplakin was analyzed in the regulations of apical Crb domain in developing Drosophila photoreceptors. METHODOLOGY/PRINCIPAL FINDINGS: The localization pattern of Spectraplakin in developing pupal photoreceptors showed a unique intracellular distribution. Spectraplakin localized at rhabdomere terminal web which is at the basal side of the apical Crb or rhabdomere, and in between the adherens junctions. The spectraplakin mutant photoreceptors showed dramatic mislocalizations of Crb, adherens junctions, and the stable microtubules. This role of Spectraplakin in Crb and adherens junction regulation was further supported by spectraplakin's gain-of-function phenotype. Spectraplakin overexpression in photoreceptors caused a cell polarity defect including dramatic mislocalization of Crb, adherens junctions and the stable microtubules in the developing photoreceptors. Furthermore, a strong genetic interaction between spectraplakin and crb was found using a genetic modifier test. CONCLUSIONS/SIGNIFICANCE: In summary, we found a unique localization of Spectraplakin in photoreceptors, and identified the role of spectraplakin in the regulation of the apical Crb domain and adherens junctions through genetic mutational analysis. Our data suggest that Spectraplakin, an actin-microtubule cross-linker, is essential in the apical and adherens junction controls during the photoreceptors morphogenesis.

  18. 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.

  19. 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...

  20. 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.

  1. 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

  2. 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...

  3. Unidirectional photoreceptor-to-Muller glia coupling and unique K+ channel expression in Caiman retina.

    Directory of Open Access Journals (Sweden)

    Astrid Zayas-Santiago

    Full Text Available BACKGROUND: Müller cells, the principal glial cells of the vertebrate retina, are fundamental for the maintenance and function of neuronal cells. In most vertebrates, including humans, Müller cells abundantly express Kir4.1 inwardly rectifying potassium channels responsible for hyperpolarized membrane potential and for various vital functions such as potassium buffering and glutamate clearance; inter-species differences in Kir4.1 expression were, however, observed. Localization and function of potassium channels in Müller cells from the retina of crocodiles remain, hitherto, unknown. METHODS: We studied retinae of the Spectacled caiman (Caiman crocodilus fuscus, endowed with both diurnal and nocturnal vision, by (i immunohistochemistry, (ii whole-cell voltage-clamp, and (iii fluorescent dye tracing to investigate K+ channel distribution and glia-to-neuron communications. RESULTS: Immunohistochemistry revealed that caiman Müller cells, similarly to other vertebrates, express vimentin, GFAP, S100β, and glutamine synthetase. In contrast, Kir4.1 channel protein was not found in Müller cells but was localized in photoreceptor cells. Instead, 2P-domain TASK-1 channels were expressed in Müller cells. Electrophysiological properties of enzymatically dissociated Müller cells without photoreceptors and isolated Müller cells with adhering photoreceptors were significantly different. This suggests ion coupling between Müller cells and photoreceptors in the caiman retina. Sulforhodamine-B injected into cones permeated to adhering Müller cells thus revealing a uni-directional dye coupling. CONCLUSION: Our data indicate that caiman Müller glial cells are unique among vertebrates studied so far by predominantly expressing TASK-1 rather than Kir4.1 K+ channels and by bi-directional ion and uni-directional dye coupling to photoreceptor cells. This coupling may play an important role in specific glia-neuron signaling pathways and in a new type of K

  4. 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.

  5. 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.

  6. 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

  7. X-linked cone dystrophy caused by mutation of the red and green cone opsins.

    Science.gov (United States)

    Gardner, Jessica C; Webb, Tom R; Kanuga, Naheed; Robson, Anthony G; Holder, Graham E; Stockman, Andrew; Ripamonti, Caterina; Ebenezer, Neil D; Ogun, Olufunmilola; Devery, Sophie; Wright, Genevieve A; Maher, Eamonn R; Cheetham, Michael E; Moore, Anthony T; Michaelides, Michel; Hardcastle, Alison J

    2010-07-01

    X-linked cone and cone-rod dystrophies (XLCOD and XLCORD) are a heterogeneous group of progressive disorders that solely or primarily affect cone photoreceptors. Mutations in exon ORF15 of the RPGR gene are the most common underlying cause. In a previous study, we excluded RPGR exon ORF15 in some families with XLCOD. Here, we report genetic mapping of XLCOD to Xq26.1-qter. A significant LOD score was detected with marker DXS8045 (Z(max) = 2.41 [theta = 0.0]). The disease locus encompasses the cone opsin gene array on Xq28. Analysis of the array revealed a missense mutation (c. 529T>C [p. W177R]) in exon 3 of both the long-wavelength-sensitive (LW, red) and medium-wavelength-sensitive (MW, green) cone opsin genes that segregated with disease. Both exon 3 sequences were identical and were derived from the MW gene as a result of gene conversion. The amino acid W177 is highly conserved in visual and nonvisual opsins across species. We show that W177R in MW opsin and the equivalent W161R mutation in rod opsin result in protein misfolding and retention in the endoplasmic reticulum. We also demonstrate that W177R misfolding, unlike the P23H mutation in rod opsin that causes retinitis pigmentosa, is not rescued by treatment with the pharmacological chaperone 9-cis-retinal. Mutations in the LW/MW cone opsin gene array can, therefore, lead to a spectrum of disease, ranging from color blindness to progressive cone dystrophy (XLCOD5). PMID:20579627

  8. CHARACTERIZATION OF SOLID CONES

    Institute of Scientific and Technical Information of China (English)

    Qiu Jinghui

    2008-01-01

    The author gives a dual characterization of solid cones in locally convex spaces.From this the author obtains some criteria for judging convex cones to be solid in various inds of locally convex spaces. Using a general expression of the interior of a solid cone,the author obtains a number of necessary and sufficient conditions for convex cones to be solid in the framework of Banach spaces. In particular, the author gives a dual relationship between solid cones and generalized sharp cones. The related known results are improved and extended.

  9. 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

  10. 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

  11. 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 ...

  12. 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.

  13. 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 ...

  14. 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 ...

  15. Channeling of red and green cone inputs to the zebrafish optomotor response.

    Science.gov (United States)

    Orger, Michael B; Baier, Herwig

    2005-01-01

    Visual systems break scenes down into individual features, processed in distinct channels, and then selectively recombine those features according to the demands of particular behavioral tasks. In primates, for example, there are distinct pathways for motion and form processing. While form vision utilizes color information, motion pathways receive input from only a subset of cone photoreceptors and are generally colorblind. To explore the link between early channeling of visual information and behavioral output across vertebrate species, we measured the chromatic inputs to the optomotor response of larval zebrafish. Using cone-isolating gratings, we found that there is a strong input from both red and green cones but not short-wavelength cones, which nevertheless do contribute to another behavior, phototaxis. Using a motion-nulling method, we measured precisely the input strength of gratings that stimulated cones in combination. The fish do not respond to gratings that stimulate different cone types out of phase, but have an enhanced response when the cones are stimulated together. This shows that red and green cone signals are pooled at a stage before motion detection. Since the two cone inputs are combined into a single 'luminance' channel, the response to sinusoidal gratings is colorblind. However, we also find that the relative contributions of the two cones at isoluminance varies with spatial frequency. Therefore, natural stimuli, which contain a mixture of spatial frequencies, are likely to be visible regardless of their chromatic composition. PMID:16079003

  16. Intracellular pH modulates inner segment calcium homeostasis in vertebrate photoreceptors

    Science.gov (United States)

    Mercer, Aaron J.; Thoreson, Wallace B.; Barabas, Peter

    2011-01-01

    Neuronal metabolic and electrical activity is associated with shifts in intracellular pH (pHi) proton activity and state-dependent changes in activation of signaling pathways in the plasma membrane, cytosol, and intracellular compartments. We investigated interactions between two intracellular messenger ions, protons and calcium (Ca2+), in salamander photoreceptor inner segments loaded with Ca2+ and pH indicator dyes. Resting cytosolic pH in rods and cones in HEPES-based saline was acidified by ∼0.4 pH units with respect to pH of the superfusing saline (pH = 7.6), indicating that dissociated inner segments experience continuous acid loading. Cytosolic alkalinization with ammonium chloride (NH4Cl) depolarized photoreceptors and stimulated Ca2+ release from internal stores, yet paradoxically also evoked dose-dependent, reversible decreases in [Ca2+]i. Alkalinization-evoked [Ca2+]i decreases were independent of voltage-operated and store-operated Ca2+ entry, plasma membrane Ca2+ extrusion, and Ca2+ sequestration into internal stores. The [Ca2+]i-suppressive effects of alkalinization were antagonized by the fast Ca2+ buffer BAPTA, suggesting that pHi directly regulates Ca2+ binding to internal anionic sites. In summary, this data suggest that endogenously produced protons continually modulate the membrane potential, release from Ca2+ stores, and intracellular Ca2+ buffering in rod and cone inner segments. PMID:20881233

  17. 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

  18. Calcium homeostasis in fly photoreceptor cells

    NARCIS (Netherlands)

    Oberwinkler, J

    2002-01-01

    In fly photoreceptor cells, two processes dominate the Ca2+ homeostasis: light-induced Ca2+ influx through members of the TRP family of ion channels, and Ca2+ extrusion by Na+/Ca2+ exchange.Ca2+ release from intracellular stores is quantitatively insignificant. Both, the light-activated channels and

  19. 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.

  20. 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

  1. 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.

  2. Ultrastructure alterations of retinal photoreceptors of the black rat,Rattus rattus exposed to certain heavy metals

    Directory of Open Access Journals (Sweden)

    Elsayed F. A. El-Dawi¹ and Naima I. Naguib²

    2010-12-01

    Full Text Available Aim of work: This study was designed to investigate the impact of lead and cadmium on the retinal photoreceptors of rats. Material &Methods: Adult black rats, Rattus rattus, were selected and divided into control and exposed groups. The exposed group was housed in industrial car batteries room containing fumes of lead and cadmium. The retina prepared for scanning and transmission electron microscopy. Results: The scanning electron microscopy revealed different lead-cadmium changes represented by gradual increasing in spaces between segments of the photoreceptors, associated with swelling of their inner segments and accompanied with rupture, degeneration and decreased numbers of some rods and cones in the outer segments. Disorganization, shortening, a decrease in number of the photoreceptors and a great deformity were the characteristic changes after prolonged exposure to the heavy metals. The aforementioned damages of the photoreceptors were confirmed at the ultrastructural level using transmission electron microscope in the form of progressive disorganization, shortening, swelling, widening of the intradiscal spaces, vacuolization and degeneration of the lamellae of the outer segments (OS, followed by the damage of mitochondria of the inner segments(IS. Excessive penetration of the processes of the pigmented epithelium (PE filled with pigments of different shapes and sizes between the damaged segments were noted. These pathological changes were considered the first symptoms in the retinal toxicity. Conclusion: The present results are alarming and call for further investigations to elucidate the impact of exposure to these heavy metals for longer periods on the rat vision and eye structure.

  3. 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.

  4. 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.

  5. 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

  6. Berkeley Lighting Cone

    Energy Technology Data Exchange (ETDEWEB)

    Lask, Kathleen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gadgil, Ashok [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2016-10-24

    A lighting cone is a simple metal cone placed on the fuel bed of a stove during ignition to act as a chimney, increasing the draft through the fuel bed. Many stoves tend to be difficult to light due to poor draft through the fuel bed, so lighting cones are used in various parts of the world as an inexpensive accessory to help with ignition.

  7. 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

  8. 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

  9. Growth cone collapse assay.

    Science.gov (United States)

    Cook, Geoffrey M W; Jareonsettasin, Prem; Keynes, Roger J

    2014-01-01

    The growth cone collapse assay has proved invaluable in detecting and purifying axonal repellents. Glycoproteins/proteins present in detergent extracts of biological tissues are incorporated into liposomes, added to growth cones in culture and changes in morphology are then assessed. Alternatively purified or recombinant molecules in aqueous solution may be added directly to the cultures. In both cases after a defined period of time (up to 1 h), the cultures are fixed and then assessed by inverted phase contrast microscopy for the percentage of growth cones showing a collapsed profile with loss of flattened morphology, filopodia, and lamellipodia.

  10. 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

  11. 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.

  12. Lunar cinder cones.

    Science.gov (United States)

    McGetchin, T R; Head, J W

    1973-04-01

    Data on terrestrial eruptions of pyroclastic material and ballistic considerations suggest that in the lunar environment (vacuum and reduced gravity) low-rimmed pyroclastic rings are formed rather than the high-rimmed cinder cones so abundant on the earth. Dark blanketing deposits in the Taurus-Littrow region (Apollo 17 landing area) are interpreted as being at least partly composed of lunar counterparts of terrestrial cinder cones.

  13. 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

    2016-07-01

    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.

  14. 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

  15. 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

  16. 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...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    Cannabinoids exert their actions mainly through two receptors, the cannabinoid CB1 receptor (CB1R) and cannabinoid CB2 receptor (CB2R). In recent years, the G-protein coupled receptor 55 (GPR55) was suggested as a cannabinoid receptor based on its activation by anandamide and tetrahydrocannabinol....... Yet, its formal classification is still a matter of debate. CB1R and CB2R expression patterns are well described for rodent and monkey retinas. In the monkey retina, CB1R has been localized in its neural (cone photoreceptor, horizontal, bipolar, amacrine and ganglion cells) and CB2R in glial...... in cones. The labeling of GPR55 in rods was further assessed with a 3D visualization in the XZ and YZ planes thus confirming its exclusive expression in rods. These results provide data on the distribution of GPR55 in the monkey retina, different than CB1R and CB2R. The presence of GPR55 in rods suggests...

  18. Beta-ionone activates and bleaches visual pigment in salamander photoreceptors.

    Science.gov (United States)

    Isayama, Tomoki; McCabe England, S L; Crouch, R K; Zimmerman, A L; Makino, C L

    2009-01-01

    Vision begins with photoisomerization of 11-cis retinal to the all-trans conformation within the chromophore-binding pocket of opsin, leading to activation of a biochemical cascade. Release of all-trans retinal from the binding pocket curtails but does not fully quench the ability of opsin to activate transducin. All-trans retinal and some other analogs, such as beta-ionone, enhance opsin's activity, presumably on binding the empty chromophore-binding pocket. By recording from isolated salamander photoreceptors and from patches of rod outer segment membrane, we now show that high concentrations of beta-ionone suppressed circulating current in dark-adapted green-sensitive rods by inhibiting the cyclic nucleotide-gated channels. There were also decreases in circulating current and flash sensitivity, and accelerated flash response kinetics in dark-adapted blue-sensitive (BS) rods and cones, and in ultraviolet-sensitive cones, at concentrations too low to inhibit the channels. These effects persisted in BS rods even after incubation with 9-cis retinal to ensure complete regeneration of their visual pigment. After long exposures to high concentrations of beta-ionone, recovery was incomplete unless 9-cis retinal was given, indicating that visual pigment had been bleached. Therefore, we propose that beta-ionone activates and bleaches some types of visual pigments, mimicking the effects of light.

  19. 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 ...

  20. 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

  1. 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...

  2. 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...

  3. 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...

  4. 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.

  5. Derivation of Traceable and Transplantable Photoreceptors from Mouse Embryonic Stem Cells

    Directory of Open Access Journals (Sweden)

    Sarah Decembrini

    2014-06-01

    Full Text Available Retinal degenerative diseases resulting in the loss of photoreceptors are one of the major causes of blindness. Photoreceptor replacement therapy is a promising treatment because the transplantation of retina-derived photoreceptors can be applied now to different murine retinopathies to restore visual function. To have an unlimited source of photoreceptors, we derived a transgenic embryonic stem cell (ESC line in which the Crx-GFP transgene is expressed in photoreceptors and assessed the capacity of a 3D culture protocol to produce integration-competent photoreceptors. This culture system allows the production of a large number of photoreceptors recapitulating the in vivo development. After transplantation, integrated cells showed the typical morphology of mature rods bearing external segments and ribbon synapses. We conclude that a 3D protocol coupled with ESCs provides a safe and renewable source of photoreceptors displaying a development and transplantation competence comparable to photoreceptors from age-matched retinas.

  6. 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

  7. 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

  8. 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. 

  9. 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.

  10. Mutations in the unfolded protein response regulator ATF6 cause the cone dysfunction disorder achromatopsia.

    Science.gov (United States)

    Kohl, Susanne; Zobor, Ditta; Chiang, Wei-Chieh; Weisschuh, Nicole; Staller, Jennifer; Gonzalez Menendez, Irene; Chang, Stanley; Beck, Susanne C; Garcia Garrido, Marina; Sothilingam, Vithiyanjali; Seeliger, Mathias W; Stanzial, Franco; Benedicenti, Francesco; Inzana, Francesca; Héon, Elise; Vincent, Ajoy; Beis, Jill; Strom, Tim M; Rudolph, Günther; Roosing, Susanne; Hollander, Anneke I den; Cremers, Frans P M; Lopez, Irma; Ren, Huanan; Moore, Anthony T; Webster, Andrew R; Michaelides, Michel; Koenekoop, Robert K; Zrenner, Eberhart; Kaufman, Randal J; Tsang, Stephen H; Wissinger, Bernd; Lin, Jonathan H

    2015-07-01

    Achromatopsia (ACHM) is an autosomal recessive disorder characterized by color blindness, photophobia, nystagmus and severely reduced visual acuity. Using homozygosity mapping and whole-exome and candidate gene sequencing, we identified ten families carrying six homozygous and two compound-heterozygous mutations in the ATF6 gene (encoding activating transcription factor 6A), a key regulator of the unfolded protein response (UPR) and cellular endoplasmic reticulum (ER) homeostasis. Patients had evidence of foveal hypoplasia and disruption of the cone photoreceptor layer. The ACHM-associated ATF6 mutations attenuate ATF6 transcriptional activity in response to ER stress. Atf6(-/-) mice have normal retinal morphology and function at a young age but develop rod and cone dysfunction with increasing age. This new ACHM-related gene suggests a crucial and unexpected role for ATF6A in human foveal development and cone function and adds to the list of genes that, despite ubiquitous expression, when mutated can result in an isolated retinal photoreceptor phenotype. PMID:26029869

  11. 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.

  12. Photoreceptor Outer Segment on Internal Limiting Membrane after Macular Hole Surgery: Implications for Pathogenesis

    Directory of Open Access Journals (Sweden)

    Michael E. Grinton

    2015-09-01

    Full Text Available Purpose: This report presents a case, which highlights key principles in the pathophysiology of macular holes. It has been hypothesized that anteroposterior (AP and tangential vitreous traction on the fovea are the primary underlying factors causing macular holes [Nischal and Pearson; in Kanski and Bowling: Clinical Ophthalmology: A Systemic Approach, 2011, pp 629-631]. Spectral domain optical coherence tomography (OCT has subsequently corroborated this theory in part but shown that AP vitreofoveal traction is the more common scenario [Steel and Lotery: Eye 2013;27:1-21]. Methods: This study was conducted as a single case report. Results: A 63-year old female presented to her optician with blurred and distorted vision in her left eye. OCT showed a macular hole with a minimum linear diameter of 370 µm, with persistent broad vitreofoveal attachment on both sides of the hole edges. The patient underwent combined left phacoemulsification and pars plana vitrectomy, internal limiting membrane (ILM peel and gas injection. The ILM was examined by electron microscopy and showed the presence of a cone outer segment on the retinal side. Post-operative OCT at 11 weeks showed a closed hole with recovery of the foveal contour and good vision. Conclusion: Our case shows the presence of a photoreceptor outer segment on the retinal side of the ILM and reinforces the importance of tangential traction in the development of some macula holes. The case highlights the theory of transmission of inner retinal forces to the photoreceptors via Müller cells and how a full thickness macular hole defect can occur in the absence of AP vitreomacular traction.

  13. Photoreceptor Outer Segment on Internal Limiting Membrane after Macular Hole Surgery: Implications for Pathogenesis

    Science.gov (United States)

    Grinton, Michael E.; Sandinha, Maria T.; Steel, David H.W.

    2015-01-01

    Purpose This report presents a case, which highlights key principles in the pathophysiology of macular holes. It has been hypothesized that anteroposterior (AP) and tangential vitreous traction on the fovea are the primary underlying factors causing macular holes [Nischal and Pearson; in Kanski and Bowling: Clinical Ophthalmology: A Systemic Approach, 2011, pp 629–631]. Spectral domain optical coherence tomography (OCT) has subsequently corroborated this theory in part but shown that AP vitreofoveal traction is the more common scenario [Steel and Lotery: Eye 2013;27:1–21]. Methods This study was conducted as a single case report. Results A 63-year old female presented to her optician with blurred and distorted vision in her left eye. OCT showed a macular hole with a minimum linear diameter of 370 µm, with persistent broad vitreofoveal attachment on both sides of the hole edges. The patient underwent combined left phacoemulsification and pars plana vitrectomy, internal limiting membrane (ILM) peel and gas injection. The ILM was examined by electron microscopy and showed the presence of a cone outer segment on the retinal side. Post-operative OCT at 11 weeks showed a closed hole with recovery of the foveal contour and good vision. Conclusion Our case shows the presence of a photoreceptor outer segment on the retinal side of the ILM and reinforces the importance of tangential traction in the development of some macula holes. The case highlights the theory of transmission of inner retinal forces to the photoreceptors via Müller cells and how a full thickness macular hole defect can occur in the absence of AP vitreomacular traction. PMID:26557083

  14. 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

  15. Cone Algorithm of Spinning Vehicles under Dynamic Coning Environment

    Directory of Open Access Journals (Sweden)

    Shuang-biao Zhang

    2015-01-01

    Full Text Available Due to the fact that attitude error of vehicles has an intense trend of divergence when vehicles undergo worsening coning environment, in this paper, the model of dynamic coning environment is derived firstly. Then, through investigation of the effect on Euler attitude algorithm for the equivalency of traditional attitude algorithm, it is found that attitude error is actually the roll angle error including drifting error and oscillating error, which is induced directly by dynamic coning environment and further affects the pitch angle and yaw angle through transferring. Based on definition of the cone frame and cone attitude, a cone algorithm is proposed by rotation relationship to calculate cone attitude, and the relationship between cone attitude and Euler attitude of spinning vehicle is established. Through numerical simulations with different conditions of dynamic coning environment, it is shown that the induced error of Euler attitude fluctuates by the variation of precession and nutation, especially by that of nutation, and the oscillating frequency of roll angle error is twice that of pitch angle error and yaw angle error. In addition, the rotation angle is more competent to describe the spinning process of vehicles under coning environment than Euler angle gamma, and the real pitch angle and yaw angle are calculated finally.

  16. 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.

  17. 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; ...

  18. 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.

  19. The Holographic Entropy Cone

    CERN Document Server

    Bao, Ning; Ooguri, Hirosi; Stoica, Bogdan; Sully, James; Walter, Michael

    2015-01-01

    We initiate a systematic enumeration and classification of entropy inequalities satisfied by the Ryu-Takayanagi formula for conformal field theory states with smooth holographic dual geometries. For 2, 3, and 4 regions, we prove that the strong subadditivity and the monogamy of mutual information give the complete set of inequalities. This is in contrast to the situation for generic quantum systems, where a complete set of entropy inequalities is not known for 4 or more regions. We also find an infinite new family of inequalities applicable to 5 or more regions. The set of all holographic entropy inequalities bounds the phase space of Ryu-Takayanagi entropies, defining the holographic entropy cone. We characterize this entropy cone by reducing geometries to minimal graph models that encode the possible cutting and gluing relations of minimal surfaces. We find that, for a fixed number of regions, there are only finitely many independent entropy inequalities. To establish new holographic entropy inequalities, w...

  20. 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...

  1. 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 ...

  2. 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.

  3. 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.

  4. 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

  5. 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 ...

  6. 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

  7. 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.

  8. Calcium homeostasis and cone signaling are regulated by interactions between calcium stores and plasma membrane ion channels.

    Directory of Open Access Journals (Sweden)

    Tamas Szikra

    Full Text Available Calcium is a messenger ion that controls all aspects of cone photoreceptor function, including synaptic release. The dynamic range of the cone output extends beyond the activation threshold for voltage-operated calcium entry, suggesting another calcium influx mechanism operates in cones hyperpolarized by light. We have used optical imaging and whole-cell voltage clamp to measure the contribution of store-operated Ca(2+ entry (SOCE to Ca(2+ homeostasis and its role in regulation of neurotransmission at cone synapses. Mn(2+ quenching of Fura-2 revealed sustained divalent cation entry in hyperpolarized cones. Ca(2+ influx into cone inner segments was potentiated by hyperpolarization, facilitated by depletion of intracellular Ca(2+ stores, unaffected by pharmacological manipulation of voltage-operated or cyclic nucleotide-gated Ca(2+ channels and suppressed by lanthanides, 2-APB, MRS 1845 and SKF 96365. However, cation influx through store-operated channels crossed the threshold for activation of voltage-operated Ca(2+ entry in a subset of cones, indicating that the operating range of inner segment signals is set by interactions between store- and voltage-operated Ca(2+ channels. Exposure to MRS 1845 resulted in approximately 40% reduction of light-evoked postsynaptic currents in photopic horizontal cells without affecting the light responses or voltage-operated Ca(2+ currents in simultaneously recorded cones. The spatial pattern of store-operated calcium entry in cones matched immunolocalization of the store-operated sensor STIM1. These findings show that store-operated channels regulate spatial and temporal properties of Ca(2+ homeostasis in vertebrate cones and demonstrate their role in generation of sustained excitatory signals across the first retinal synapse.

  9. 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 ...

  10. 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...

  11. 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...

  12. 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...

  13. BIRD FLU (AVIAN INFLUENZA)

    OpenAIRE

    Ali ACAR; 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, ...

  14. 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...

  15. 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...

  16. Light Cone Current Algebra

    CERN Document Server

    Fritzsch, Harald

    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 require study.

  17. 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...

  18. Mapping nonlinear receptive field structure in primate retina at single cone resolution.

    Science.gov (United States)

    Freeman, Jeremy; Field, Greg D; Li, Peter H; Greschner, Martin; Gunning, Deborah E; Mathieson, Keith; Sher, Alexander; Litke, Alan M; Paninski, Liam; Simoncelli, Eero P; Chichilnisky, E J

    2015-01-01

    The function of a neural circuit is shaped by the computations performed by its interneurons, which in many cases are not easily accessible to experimental investigation. Here, we elucidate the transformation of visual signals flowing from the input to the output of the primate retina, using a combination of large-scale multi-electrode recordings from an identified ganglion cell type, visual stimulation targeted at individual cone photoreceptors, and a hierarchical computational model. The results reveal nonlinear subunits in the circuity of OFF midget ganglion cells, which subserve high-resolution vision. The model explains light responses to a variety of stimuli more accurately than a linear model, including stimuli targeted to cones within and across subunits. The recovered model components are consistent with known anatomical organization of midget bipolar interneurons. These results reveal the spatial structure of linear and nonlinear encoding, at the resolution of single cells and at the scale of complete circuits.

  19. 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.

  20. 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

  1. 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...

  2. 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...

  3. 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.

  4. 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...

  5. 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...

  6. 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.)

  7. Activation of autophagy in photoreceptor necroptosis after experimental retinal detachment

    Institute of Scientific and Technical Information of China (English)

    Kai; Dong; Zi-Cheng; Zhu; Feng-Hua; Wang; Gen-Jie; Ke; Zhang; Yu; Xun; Xu

    2014-01-01

    AIM:To investigate whether photoreceptor necroptosis induced by z-VAD-FMK(pan caspase inhibitor) was involved the activation of autophagy and whether Necrostatin-1, a specific necroptosis inhibitor, could inhibit this induction of autophagy after experimental retinal detachment.METHODS:Experimental retinal detachment models were created in Sprague-Dawley rats by subretinal injection of sodium hyaluronate and subretinal injections of z-VAD-FMK, vehicle or z-VAD-FMK plus Necrostatin-1.Three days after retinal detachment, morphologic changes were observed by transmission electron microscopy. In other animals, retinas were subjected to immunoprecipitation and Western Blotting, then probed with anti-RIP1, phosphoserine, LC-3II or caspase 8antibody.RESULTS:It was proved by immunoprecipitation and western blotting, that photoreceptor necroptosis was mediated by caspase-8 inhibition and receptor interacting protein kinase(RIP1) phosphorylation activation. Transmission electron microscope and western blotting results indicated that photoreceptornecroptosis was involved the LC-3II and autophagosomes induction. We also discovered Necrostatin-1 could inhibit RIP1 phosphorylation and LC-3II induction.CONCLUSION:These data firstly indicate photoreceptor necroptosis is associated with the activation of autophagy. Necrostatin-1 protects photoreceptors from necroptosis and autophagy by down-regulation of RIP1 phosphorylation and LC-3II.

  8. 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.

  9. 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...

  10. 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.

  11. 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.

  12. Lentiviral expression of retinal guanylate cyclase-1 (RetGC1 restores vision in an avian model of childhood blindness.

    Directory of Open Access Journals (Sweden)

    Melissa L Williams

    2006-06-01

    Full Text Available BACKGROUND: Leber congenital amaurosis (LCA is a genetically heterogeneous group of retinal diseases that cause congenital blindness in infants and children. Mutations in the GUCY2D gene that encodes retinal guanylate cyclase-1 (retGC1 were the first to be linked to this disease group (LCA type 1 [LCA1] and account for 10%-20% of LCA cases. These mutations disrupt synthesis of cGMP in photoreceptor cells, a key second messenger required for function of these cells. The GUCY1*B chicken, which carries a null mutation in the retGC1 gene, is blind at hatching and serves as an animal model for the study of LCA1 pathology and potential treatments in humans. METHODS AND FINDINGS: A lentivirus-based gene transfer vector carrying the GUCY2D gene was developed and injected into early-stage GUCY1*B embryos to determine if photoreceptor function and sight could be restored to these animals. Like human LCA1, the avian disease shows early-onset blindness, but there is a window of opportunity for intervention. In both diseases there is a period of photoreceptor cell dysfunction that precedes retinal degeneration. Of seven treated animals, six exhibited sight as evidenced by robust optokinetic and volitional visual behaviors. Electroretinographic responses, absent in untreated animals, were partially restored in treated animals. Morphological analyses indicated there was slowing of the retinal degeneration. CONCLUSIONS: Blindness associated with loss of function of retGC1 in the GUCY1*B avian model of LCA1 can be reversed using viral vector-mediated gene transfer. Furthermore, this reversal can be achieved by restoring function to a relatively low percentage of retinal photoreceptors. These results represent a first step toward development of gene therapies for one of the more common forms of childhood blindness.

  13. ES1 is a mitochondrial enlarging factor contributing to form mega-mitochondria in zebrafish cones.

    Science.gov (United States)

    Masuda, Takamasa; Wada, Yasutaka; Kawamura, Satoru

    2016-03-01

    Total mass of mitochondria increases during cell proliferation and differentiation through mitochondrial biogenesis, which includes mitochondrial proliferation and growth. During the mitochondrial growth, individual mitochondria have been considered to be enlarged independently of mitochondrial fusion. However, molecular basis for this enlarging process has been poorly understood. Cone photoreceptor cells in the retina possess large mitochondria, so-called mega-mitochondria that have been considered to arise via the enlarging process. Here we show that ES1 is a novel mitochondria-enlarging factor contributing to form mega-mitochondria in cones. ES1 is specifically expressed in cones and localized to mitochondria including mega-mitochondria. Knockdown of ES1 markedly reduced the mitochondrial size in cones. In contrast, ectopic expression of ES1 in rods significantly increased both the size of individual mitochondria and the total mass of the mitochondrial cluster without changing the number of them. RNA-seq analysis showed that ERRα and its downstream mitochondrial genes were significantly up-regulated in the ES1-expressing rods, suggesting facilitation of mitochondrial enlargement via ERRα-dependent processes. Furthermore, higher energy state was detected in the ES1-expressing rods, indicating that the enlarged mitochondria by ES1 are capable of producing high energy. ES1 is the mitochondrial protein that is first found to promote enlargement of individual mitochondria.

  14. 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

  15. 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.

  16. 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.

  17. Multipotent stem cells isolated from the adult mouse retina are capable of producing functional photoreceptor cells

    Institute of Scientific and Technical Information of China (English)

    Tianqing Li; Michelle Lewallen; Shuyi Chen; Wei Yu; Nian Zhang; Ting Xie

    2013-01-01

    Various stem cell types have been tested for their potential application in treating photoreceptor degenerative diseases,such as retinitis pigmentosa (RP) and age-related macular degeneration (AMD).Only embryonic stem cells (ESCs) have so far been shown to generate functional photoreceptor cells restoring light response of photoreceptordeficient mice,but there is still some concern of tumor formation.In this study,we have successfully cultured Nestin+Sox2+Pax6+ multipotent retinal stem cells (RSCs) from the adult mouse retina,which are capable of producing functional photoreceptor cells that restore the light response of photoreceptor-deficient rd1 mutant mice following transplantation.After they have been expanded for over 35 passages in the presence of FGF and EGF,the cultured RSCs still maintain stable proliferation and differentiation potential.Under proper differentiation conditions,they can differentiate into all the major retinal cell types found in the adult retina.More importantly,they can efficiently differentiate into photoreceptor cells under optimized differentiation conditions.Following transplantation into the subretinal space of slowly degenerating rd7 mutant eyes,RSC-derived photoreceptor cells integrate into the retina,morphologically resembling endogenous photoreceptors and forming synapases with resident retinal neurons.When transplanted into eyes of photoreceptor-deficient rd1 mutant mice,a RP model,RSC-derived photoreceptors can partially restore light response,indicating that those RSC-derived photoreceptors are functional.Finally,there is no evidence for tumor formation in the photoreceptor-transplanted eyes.Therefore,this study has demonstrated that RSCs isolated from the adult retina have the potential of producing functional photoreceptor cells that can potentially restore lost vision caused by loss of photoreceptor cells in RP and AMD.

  18. 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

  19. 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

  20. 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

  1. 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.

  2. 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 ...

  3. The light-cone theorem

    Energy Technology Data Exchange (ETDEWEB)

    Choquet-Bruhat, Yvonne [Academie des Sciences, Paris (France); Chrusciel, Piotr T [Federation Denis Poisson, LMPT, Tours (France); MartIn-GarcIa, Jose M [Laboratoire Univers et Theories, CNRS, Meudon, and Universite Paris Diderot (France)

    2009-07-07

    We prove that the area of cross-sections of light cones, in spacetimes satisfying suitable energy conditions, is smaller than or equal to that of the corresponding cross-sections in Minkowski, or de Sitter, or anti-de Sitter spacetime. The equality holds if and only if the metric coincides with the corresponding model in the domain of dependence of the light cone.

  4. The light-cone theorem

    CERN Document Server

    Choquet-Bruhat, Yvonne; Martin-Garcia, Jose M

    2009-01-01

    We prove that the area of cross-sections of light-cones, in space-times satisfying suitable energy conditions, is smaller than or equal to that of the corresponding cross-sections in Minkowski, or de Sitter, or anti-de Sitter space-time. The equality holds if and only if the metric coincides with the corresponding model in the domain of dependence of the light-cone.

  5. 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...

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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

  11. 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.

  12. 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

  13. 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).

  14. 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...

  15. 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

  16. 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

  17. 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 ...

  18. 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...

  19. 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...

  20. 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...

  1. 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.

  2. 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

  3. 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

  4. 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

  5. Shatter cones: (Mis)understood?

    Science.gov (United States)

    Osinski, Gordon R; Ferrière, Ludovic

    2016-08-01

    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 D sc = 0.4 D a, where D sc is the maximum spatial extent of in situ shatter cones, and D a 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

  6. 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

  7. 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.

  8. The Avian Proghrelin System

    Directory of Open Access Journals (Sweden)

    Mark P. Richards

    2010-01-01

    Full Text Available To understand how the proghrelin system functions in regulating growth hormone release and food intake as well as defining its pleiotropic roles in such diverse physiological processes as energy homeostasis, gastrointestinal tract function and reproduction require detailed knowledge of the structure and function of the components that comprise this system. These include the preproghrelin gene that encodes the proghrelin precursor protein from which two peptide hormones, ghrelin and obestatin, are derived and the cognate receptors that bind proghrelin-derived peptides to mediate their physiological actions in different tissues. Also key to the functioning of this system is the posttranslational processing of the proghrelin precursor protein and the individual peptides derived from it. While this system has been intensively studied in a variety of animal species and humans over the last decade, there has been considerably less investigation of the avian proghrelin system which exhibits some unique differences compared to mammals. This review summarizes what is currently known about the proghrelin system in birds and offers new insights into the nature and function of this important endocrine system. Such information facilitates cross-species comparisons and contributes to our understanding of the evolution of the proghrelin system.

  9. 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

  10. 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

  11. Measurement of Photon Statistics with Live Photoreceptor Cells

    CERN Document Server

    Sim, Nigel; Bessarab, Dmitri; Jones, C Michael; Krivitsky, Leonid

    2012-01-01

    We analyzed the electrophysiological response of an isolated rod photoreceptor of Xenopus laevis under stimulation by coherent and pseudo-thermal light sources. Using the suction electrode technique for single cell recordings and a fiber optics setup for light delivery allowed measurements of the major statistical characteristics of the rod response. The results indicate differences in average responses of rod cells to coherent and pseudo-thermal light of the same intensity and also differences in signal-to-noise ratios and second order intensity correlation functions. These findings should be relevant for interdisciplinary studies in applications of quantum optics in biology.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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

  19. 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 store...

  20. 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...

  1. Avian reproductive physiology

    Science.gov (United States)

    Gee, G.F.; Gibbons, Edward F.; Durrant, Barbara S.; Demarest, Jack

    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

  2. Antagonistic functions of two stardust isoforms in Drosophila photoreceptor cells.

    Science.gov (United States)

    Bulgakova, Natalia A; Rentsch, Michaela; Knust, Elisabeth

    2010-11-15

    Membrane-associated guanylate kinases (MAGUKs) are scaffolding proteins that organize supramolecular protein complexes, thereby partitioning the plasma membrane into spatially and functionally distinct subdomains. Their modular organization is ideally suited to organize protein complexes with cell type- or stage-specific composition, or both. Often more than one MAGUK isoform is expressed by one gene in the same cell, yet very little is known about their individual in vivo functions. Here, we show that two isoforms of Drosophila stardust, Sdt-H (formerly called Sdt-B2) and Sdt-D, which differ in their N terminus, are expressed in adult photoreceptors. Both isoforms associate with Crumbs and PATJ, constituents of the conserved Crumbs-Stardust complex. However, they form distinct complexes, localized at the stalk, a restricted region of the apical plasma membrane. Strikingly, Sdt-H and Sdt-D have antagonistic functions. While Sdt-H overexpression increases stalk membrane length and prevents light-dependent retinal degeneration, Sdt-D overexpression reduces stalk length and enhances light-dependent retinal degeneration. These results suggest that a fine-tuned balance of different Crumbs complexes regulates photoreceptor homeostasis.

  3. 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

  4. 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

  5. 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.

  6. Amyloid precursor protein is required for normal function of the rod and cone pathways in the mouse retina.

    Directory of Open Access Journals (Sweden)

    Tracy Ho

    Full Text Available Amyloid precursor protein (APP is a transmembrane glycoprotein frequently studied for its role in Alzheimer's disease. Our recent study in APP knockout (KO mice identified an important role for APP in modulating normal neuronal development in the retina. However the role APP plays in the adult retina and whether it is required for vision is unknown. In this study we evaluated the role of APP in retinal function and morphology comparing adult wildtype (WT and APP-KO mice. APP was expressed on neuronal cells of the inner retina, including horizontal, cone bipolar, amacrine and ganglion cells in WT mice. The function of the retina was assessed using the electroretinogram and although the rod photoreceptor responses were similar in APP-KO and WT mice, the post-photoreceptor, inner retinal responses of both the rod and cone pathways were reduced in APP-KO mice. These changes in inner retinal function did not translate to a substantial change in visual acuity as assessed using the optokinetic response or to changes in the gross cellular structure of the retina. These findings indicate that APP is not required for basic visual function, but that it is involved in modulating inner retinal circuitry.

  7. 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.

  8. 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...

  9. 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.

  10. A preliminary comparative study on structure and main characteristics of compound eyes in four Mexican cone borers Conophthorus spp (Coleoptera: Scolytinae

    Directory of Open Access Journals (Sweden)

    Adolfo Arturo Del Rio Mora

    2014-09-01

    Full Text Available The compound eyes of four Mexican cone borers: Conophthorus ponderosae Hopkins, C. conicolens Wood, C.michoacanae Wood and C.teocotum Wood were studied and compared by main internal and external structures as are: number of facets, eye length, ventral eye width, dorsal eye width, facet diameter, primary and secondary pigments diameter, ommatidium length and cone length, where this last seem be larger in females than males; It is described the main characteristics of dioptric apparatus and photoreceptor layer. For 2 cone borer species studied. In general all the Conophthorus species showed identically kidney-shaped eyes where the number of ommatidia or facets quantified no differed significantly between species (P= 0.0149 and sex, except for the case of C.teocotum W; the other parameters or characteristics compared are too seem for all species group studied. It was described that the general structures of the dioptric apparatus and photoreceptor layer for C.ponderosae H and C.conicolens W, where were identified the presence of 8 rhabdomeres, confirms the fact that this number of receptors is common in scolitids, which give them the possibility of a UV-sensitive navigation system added to a green sensitive motion detecting their hosts.

  11. 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.

  12. A new photosensory function for simple photoreceptors, the intrinsically photoresponsive neurons of the sea slug Onchidium

    Directory of Open Access Journals (Sweden)

    Tsukasa Gotow

    2009-12-01

    Full Text Available Simple photoreceptors, namely intrinsically light-sensitive neurons without microvilli and/or cilia, have long been known to exist in the central ganglia of crayfish, Aplysia, Onchidium, and Helix. These simple photoreceptors are not only first-order photosensory cells, but also second-order neurons (interneurons, relaying several kinds of sensory synaptic inputs. Another important issue is that the photoresponses of these simple photoreceptors show very slow kinetics and little adaptation. These characteristics suggest that the simple photoreceptors of the Onchidium have a function in non-image-forming vision, different from classical eye photoreceptors used for cording dynamic images of vision. The cited literature provides evidence that the depolarizing and hyperpolarizing photoresponses of simple photoreceptors play a role in the long-lasting potentiation of synaptic transmission of excitatory and inhibitory sensory inputs, and as well as in the potentiation and the suppression of the subsequent behavioral outputs. In short, we suggest that simple photoreceptors operate in the general potentiation of synaptic transmission and subsequent motor output; i.e., they perform a new photosensory function.

  13. STEREOLOGY AND SOME STRUCTURAL CORRELATES OF RETINAL AND PHOTORECEPTOR CELL FUNCTION

    Directory of Open Access Journals (Sweden)

    Terry M Mayhew

    2011-05-01

    Full Text Available The retina is the part of the eye which detects light, transduces it into nerve impulses and plays a significant role in visual perception. Sensitivity to light is multi-factorial and depends on the properties of photopigment molecules, their synthesis and incorporation into photoreceptor membranes and the neural circuitry between photoreceptor cells, bipolar neurons and ganglion neurons. In addition, it depends on structural factors such as the absolute and relative numbers of different types of photoreceptor neurons, their subcellular morphology, their distribution across the retina and the physical dimensions (especially surface areas and spatial arrangements of their photoreceptor membranes. At the molecular level, these membranes harbour photosensitive pigment molecules comprising transmembrane glycoproteins (opsins, which vary between photoreceptor cells and a non-protein chromophore. Phototransduction involves a conformational change in the chromophore and activation of an opsin. A transducer G protein, transducin, lowers levels of cGMP and triggers changes in membrane ion permeability including the closure of Na+ channels. This causes the plasmalemma to become less depolarized and the relative hyperpolarization stimulates ganglion cells whose axons form the optic nerve. Phosducin is a light-regulated phosphoprotein located in inner and outer segments of rod photoreceptor cells. It modulates phototransduction by binding to beta and gamma subunits of transducin. This review briefly illustrates ways in which stereology can contribute to our understanding of these processes by providing quantitative data on photoreceptor number, disk membrane surface area and the subcellular immunolocalisation of key molecules.

  14. Reprogramming Müller glia via in vivo cell fusion regenerates murine photoreceptors.

    Science.gov (United States)

    Sanges, Daniela; Simonte, Giacoma; Di Vicino, Umberto; Romo, Neus; Pinilla, Isabel; Nicolás, Marta; Cosma, Maria Pia

    2016-08-01

    Vision impairments and blindness caused by retinitis pigmentosa result from severe neurodegeneration that leads to a loss of photoreceptors, the specialized light-sensitive neurons that enable vision. Although the mammalian nervous system is unable to replace neurons lost due to degeneration, therapeutic approaches to reprogram resident glial cells to replace retinal neurons have been proposed. Here, we demonstrate that retinal Müller glia can be reprogrammed in vivo into retinal precursors that then differentiate into photoreceptors. We transplanted hematopoietic stem and progenitor cells (HSPCs) into retinas affected by photoreceptor degeneration and observed spontaneous cell fusion events between Müller glia and the transplanted cells. Activation of Wnt signaling in the transplanted HSPCs enhanced survival and proliferation of Müller-HSPC hybrids as well as their reprogramming into intermediate photoreceptor precursors. This suggests that Wnt signaling drives the reprogrammed cells toward a photoreceptor progenitor fate. Finally, Müller-HSPC hybrids differentiated into photoreceptors. Transplantation of HSPCs with activated Wnt functionally rescued the retinal degeneration phenotype in rd10 mice, a model for inherited retinitis pigmentosa. Together, these results suggest that photoreceptors can be generated by reprogramming Müller glia and that this approach may have potential as a strategy for reversing retinal degeneration. PMID:27427986

  15. UNSTEADY SUPERCAVITATING FLOW PAST CONES

    Institute of Scientific and Technical Information of China (English)

    HU Chao; YANG Hong-lan; ZHAO Cun-bao; HUANG Wen-hu

    2006-01-01

    Based on integral equation method, the study of unsteady supercavitating flow past cones is presented. The shape and length of supercavity are calculated respectively using the finite difference time discretization method. The characteristics of the shape and length of supercavities, which vary with the cone's angle and cavitation number, are investigated respectively, the varied features of some supercavity scales are analyzed when the flow field is perturbed periodically. The curves relationship between cavity length and cavitation number, which are based respectively on present method and other theories, are discussed and compared. It is obviously shown that the supercavity changes have two characteristics: retardance and wave. These results obtained would be useful in the case of design and analysis of cavitator under water.

  16. Visual function and cortical organization in carriers of blue cone monochromacy.

    Directory of Open Access Journals (Sweden)

    Ethan A Rossi

    Full Text Available Carriers of blue cone monochromacy have fewer cone photoreceptors than normal. Here we examine how this disruption at the level of the retina affects visual function and cortical organization in these individuals. Visual resolution and contrast sensitivity was measured at the preferred retinal locus of fixation and visual resolution was tested at two eccentric locations (2.5° and 8° with spectacle correction only. Adaptive optics corrected resolution acuity and cone spacing were simultaneously measured at several locations within the central fovea with adaptive optics scanning laser ophthalmoscopy (AOSLO. Fixation stability was assessed by extracting eye motion data from AOSLO videos. Retinotopic mapping using fMRI was carried out to estimate the area of early cortical regions, including that of the foveal confluence. Without adaptive optics correction, BCM carriers appeared to have normal visual function, with normal contrast sensitivity and visual resolution, but with AO-correction, visual resolution was significantly worse than normal. This resolution deficit is not explained by cone loss alone and is suggestive of an associated loss of retinal ganglion cells. However, despite evidence suggesting a reduction in the number of retinal ganglion cells, retinotopic mapping showed no reduction in the cortical area of the foveal confluence. These results suggest that ganglion cell density may not govern the foveal overrepresentation in the cortex. We propose that it is not the number of afferents, but rather the content of the information relayed to the cortex from the retina across the visual field that governs cortical magnification, as under normal viewing conditions this information is similar in both BCM carriers and normal controls.

  17. Bursting the Taylor cone bubble

    Science.gov (United States)

    Pan, Zhao; Truscott, Tadd

    2014-11-01

    A soap bubble fixed on a surface and placed in an electric field will take on the shape of a cone rather than constant curvature (dome) when the electrical field is not present. The phenomenon was introduced by J. Zeleny (1917) and studied extensively by C.T. Wilson & G.I. Taylor (1925). We revisit the Taylor cone problem by studying the deformation and bursting of soap bubbles in a point charge electric field. A single bubble takes on the shape of a cone in the electric field and a high-speed camera equipped with a micro-lens is used to observe the unsteady dynamics at the tip. Rupture occurs as a very small piece of the tip is torn away from the bubble toward the point charge. Based on experiments, a theoretical model is developed that predicts when rupture should occur. This study may help in the design of foam-removal techniques in engineering and provide a better understanding of an electrified air-liquid interface.

  18. 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.

  19. 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

  20. 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.

  1. 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...

  2. 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.

  3. 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

  4. 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.

  5. Non-image Forming Light Detection by Melanopsin, Rhodopsin, and Long-Middlewave (L/W) Cone Opsin in the Subterranean Blind Mole Rat, Spalax Ehrenbergi: Immunohistochemical Characterization, Distribution, and Connectivity.

    Science.gov (United States)

    Esquiva, Gema; Avivi, Aaron; Hannibal, Jens

    2016-01-01

    The blind mole rat, Spalax ehrenbergi, can, despite severely degenerated eyes covered by fur, entrain to the daily light/dark cycle and adapt to seasonal changes due to an intact circadian timing system. The present study demonstrates that the Spalax retina contains a photoreceptor layer, an outer nuclear layer (ONL), an outer plexiform layer (OPL), an inner nuclear layer (INL), an inner plexiform layer (IPL), and a ganglion cell layer (GCL). By immunohistochemistry, the number of melanopsin (mRGCs) and non-melanopsin bearing retinal ganglion cells was analyzed in detail. Using the ganglion cell marker RNA-binding protein with multiple splicing (RBPMS) it was shown that the Spalax eye contains 890 ± 62 RGCs. Of these, 87% (752 ± 40) contain melanopsin (cell density 788 melanopsin RGCs/mm(2)). The remaining RGCs were shown to co-store Brn3a and calretinin. The melanopsin cells were located mainly in the GCL with projections forming two dendritic plexuses located in the inner part of the IPL and in the OPL. Few melanopsin dendrites were also found in the ONL. The Spalax retina is rich in rhodopsin and long/middle wave (L/M) cone opsin bearing photoreceptor cells. By using Ctbp2 as a marker for ribbon synapses, both rods and L/M cone ribbons containing pedicles in the OPL were found in close apposition with melanopsin dendrites in the outer plexus suggesting direct synaptic contact. A subset of cone bipolar cells and all photoreceptor cells contain recoverin while a subset of bipolar and amacrine cells contain calretinin. The calretinin expressing amacrine cells seemed to form synaptic contacts with rhodopsin containing photoreceptor cells in the OPL and contacts with melanopsin cell bodies and dendrites in the IPL. The study demonstrates the complex retinal circuitry used by the Spalax to detect light, and provides evidence for both melanopsin and non-melanopsin projecting pathways to the brain.

  6. 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...

  7. Cone Penetrometer Off-Surface Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Smail, T.R.; French, p.J.; Huffman, R.K.; Hebert, P.S.

    1999-10-20

    Cone penetrometer technology accounts for approximately 50 percent of the subsurface drilling done at the Savannah River Site. This technology provides a means of collecting data for use in the characterization of the subsurface. The cone penetrometer consists of a steel cone attached to a pipe column that is hydraulically inserted into the ground. To allow researchers to accurately measure subsurface properties, without the inherent problems of cone penetrometer equipment, the Savannah River Technology Center has developed the Cone Penetrometer Off-Surface Sensor (CPOSS). The CPOSS design consists of a knife-blade mechanism mounted along the surface of a module capable of attaching to existing cone penetrometer equipment and being deployed at depths of up to 200 feet. CPOSS development is the subject of this report.

  8. 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...

  9. 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.

  10. 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

  11. 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...

  12. 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.

  13. 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 ...

  14. Gender determination of avian embryo

    Science.gov (United States)

    Daum, Keith A.; Atkinson, David A.

    2002-01-01

    Disclosed is a method for gender determination of avian embryos. During the embryo incubation process, the outer hard shells of eggs are drilled and samples of allantoic fluid are removed. The allantoic fluids are directly introduced into an ion mobility spectrometer (IMS) for analysis. The resulting spectra contain the relevant marker peaks in the positive or negative mode which correlate with unique mobilities which are sex-specific. This way, the gender of the embryo can be determined.

  15. 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...

  16. 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.

  17. Spectral sensitivity of light induced respiratory activity of photoreceptor mitochondria in the intact fly

    NARCIS (Netherlands)

    Tinbergen, J.; Stavenga, D.G.

    1987-01-01

    Fly Calliphora erythrocephala (white eyed) photoreceptors were investigated in intact, living animals by microspectrofluorometry in vivo. The fluorescence of mitochondrial flavoproteins was used to monitor transient changes in oxidative metabolism, which were induced by a test light following a stim

  18. 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...

  19. Influence of dietary melatonin on photoreceptor survival in the rat retina: an ocular toxicity study.

    Science.gov (United States)

    Wiechmann, Allan F; Chignell, Colin F; Roberts, Joan E

    2008-02-01

    Previous studies have shown that melatonin treatment increases the susceptibility of retinal photoreceptors to light-induced cell death. The purpose of this study was to evaluate under various conditions the potential toxicity of dietary melatonin on retinal photoreceptors. Male and female Fischer 344 (non-pigmented) and Long-Evans (pigmented) rats were treated with daily single doses of melatonin by gavage for a period of 14 days early in the light period or early in the dark period. In another group, rats were treated 3 times per week with melatonin early in the light period, and then exposed to high intensity illumination (1000-1500 lx; HII) for 2h, and then returned to the normal cyclic lighting regime. At the end of the treatment periods, morphometric measurements of outer nuclear layer thickness (ONL; the layer containing the photoreceptor cell nuclei) were made at specific loci throughout the retinas. In male and female non-pigmented Fischer rats, melatonin administration increased the degree of photoreceptor cell death when administered during the nighttime and during the day when followed by exposure to HII. There were some modest effects of melatonin on photoreceptor cell death when administered to Fischer rats during the day or night without exposure to HII. Melatonin treatment caused increases in the degree of photoreceptor cell death when administered in the night to male pigmented Long-Evans rats, but melatonin administration during the day, either with or without exposure to HII, had little if any effect on photoreceptor cell survival. In pigmented female Long-Evans rats, melatonin administration did not appear to have significant effects on photoreceptor cell death in any treatment group. The results of this study confirm and extend previous reports that melatonin increases the susceptibility of photoreceptors to light-induced cell death in non-pigmented rats. It further suggests that during the dark period, melatonin administration alone (i.e., no

  20. 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...

  1. 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...

  2. 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...

  3. 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

  4. 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\

  5. 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.

  6. Anatomy of the Hesse photoreceptor cell axonal system in the central nervous system of amphioxus.

    Science.gov (United States)

    Castro, Antonio; Becerra, Manuela; Manso, María Jesús; Sherwood, Nancy M; Anadón, Ramón

    2006-01-01

    The present study reports the organization of the Hesse cell axonal system in the central nervous system of the amphioxus, with the use of a polyclonal antiserum raised against lamprey gonadotropin-releasing hormone-I (GnRH-I). In the spinal cord, the rhabdomeric photoreceptor cells of the bicellular organs were well labeled with this antibody. These cells sent smooth, straight, lateral processes that bent and became beaded as they passed ventrally and crossed to the contralateral side of the cord. There, the processes of several cells aggregated to give rise to a longitudinal fiber bundle. Beaded collaterals of these processes were directed to ventral neuropil and did not appear to contact giant Rohde cell axons. The crossed projections of the Hesse photoreceptors are compared with those of vertebrate retinal ganglion cells. Other antisera raised against GnRH weakly labeled rhabdomeric photoreceptors located dorsally in the brain, the Joseph cells. The finding that GnRH antibodies label amphioxus photoreceptor cells and axons is not definitive proof that the photoreceptors contain GnRH. Regardless of whether the antibody recognizes amphioxus GnRH, which has not yet been identified by structure, the antibody has revealed the processes of the Hesse photoreceptor cells.

  7. Hypothalamic neurosecretory and circadian vasopressinergic neuronal systems in the blind cone-rod homeobox knock out mouse (Crx(-/-) ) and the 129sv wild type mouse

    DEFF Research Database (Denmark)

    Rovsing, Louise; Rath, Martin Fredensborg; Møller, Morten

    2013-01-01

    circadian AVP-rhythm. We have in this study of the brown 129sv mouse and the visual blind cone-rod homeobox gene knock out mouse (Crx(-/-) ) with degeneration of the retinal rods and cones, but a preserved non-image forming optic system, studied the temporal Avp-expression in both the neurosecretory...... at late day time and nadir during the dark in both the Crx(-/-) and the wild type mouse. None of the magnocellular neurosecretory neurons exhibited a diurnal vasopressin expression. Light stimulation of both genotypes during the dark period did not change the Avp-expression in the SCN. This shows that Avp......-expression in the mouse SCN is independent of Crx-regulated photoreceptor systems. J. Comp. Neurol., 2013. © 2013 Wiley Periodicals, Inc....

  8. 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.

  9. 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...... penetration tests with varying penetration rates conducted at a test site where the subsoil primary consists of sandy silt. It is shown how a reduced penetration rate influences the cone penetration measurements e.g. the cone resistance, pore pressure, and sleeve friction....

  10. 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...

  11. 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.

  12. 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....

  13. Mechanisms of avian songs and calls

    DEFF Research Database (Denmark)

    Larsen, Ole Næsbye

    2008-01-01

    The avian vocal organ, the syrinx, is a specialized structure located rather inaccessibly in an air sac close to the heart where the trachea bifurcates into the two primary bronchi. The syrinx of different avian taxa varies so much in position and morphology that it has been used for taxonomy. It...

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. 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

  19. Physiologically driven avian vocal synthesizer

    Science.gov (United States)

    Sitt, Jacobo D.; Arneodo, Ezequiel M.; Goller, Franz; Mindlin, Gabriel B.

    2010-03-01

    In this work, we build an electronic syrinx, i.e., a programmable electronic device capable of integrating biomechanical model equations for the avian vocal organ in order to synthesize song. This vocal prosthesis is controlled by the bird’s neural instructions to respiratory and the syringeal motor systems, thus opening great potential for studying motor control and its modification by sensory feedback mechanisms. Furthermore, a well-functioning subject-controlled vocal prosthesis can lay the foundation for similar devices in humans and thus provide directly health-related data and procedures.

  20. Rapid cohort generation and analysis of disease spectrum of large animal model of cone dystrophy.

    Directory of Open Access Journals (Sweden)

    Corinne Kostic

    Full Text Available Large animal models are an important resource for the understanding of human disease and for evaluating the applicability of new therapies to human patients. For many diseases, such as cone dystrophy, research effort is hampered by the lack of such models. Lentiviral transgenesis is a methodology broadly applicable to animals from many different species. When conjugated to the expression of a dominant mutant protein, this technology offers an attractive approach to generate new large animal models in a heterogeneous background. We adopted this strategy to mimic the phenotype diversity encounter in humans and generate a cohort of pigs for cone dystrophy by expressing a dominant mutant allele of the guanylate cyclase 2D (GUCY2D gene. Sixty percent of the piglets were transgenic, with mutant GUCY2D mRNA detected in the retina of all animals tested. Functional impairment of vision was observed among the transgenic pigs at 3 months of age, with a follow-up at 1 year indicating a subsequent slower progression of phenotype. Abnormal retina morphology, notably among the cone photoreceptor cell population, was observed exclusively amongst the transgenic animals. Of particular note, these transgenic animals were characterized by a range in the severity of the phenotype, reflecting the human clinical situation. We demonstrate that a transgenic approach using lentiviral vectors offers a powerful tool for large animal model development. Not only is the efficiency of transgenesis higher than conventional transgenic methodology but this technique also produces a heterogeneous cohort of transgenic animals that mimics the genetic variation encountered in human patients.

  1. Schiff base protonation changes in Siberian hamster ultraviolet cone pigment photointermediates.

    Science.gov (United States)

    Mooney, Victoria L; Szundi, Istvan; Lewis, James W; Yan, Elsa C Y; Kliger, David S

    2012-03-27

    Molecular structure and function studies of vertebrate ultraviolet (UV) cone visual pigments are needed to understand the molecular evolution of these photoreceptors, which uniquely contain unprotonated Schiff base linkages between the 11-cis-retinal chromophore and the opsin proteins. In this study, the Siberian hamster ultraviolet cone pigment (SHUV) was expressed and purified in an n-dodecyl-β-D-maltoside suspension for optical characterization. Time-resolved absorbance measurements, over a spectral range from 300 to 700 nm, were taken for the purified pigment at time delays from 30 ns to 4.64 s after photoexcitation using 7 ns pulses of 355 nm light. The resulting data were fit globally to a sum of exponential functions after noise reduction using singular-value decomposition. Four exponentials best fit the data with lifetimes of 1.4 μs, 210 μs, 47 ms, and 1 s. The first photointermediate species characterized here is an equilibrated mixture similar to the one formed after rhodopsin's Batho intermediate decays into equilibrium with its successor, BSI. The extremely large red shift of the SHUV Batho component relative to the pigment suggests that SHUV Batho has a protonated Schiff base and that the SHUV cone pigment itself has an unprotonated Schiff base. In contrast to SHUV Batho, the portion of the equilibrated mixture's spectrum corresponding to SHUV BSI is well fit by a model spectrum with an unprotonated Schiff base. The spectra of the next two photointermediate species revealed that they both have unprotonated Schiff bases and suggest they are analogous to rhodopsin's Lumi I and Lumi II species. After decay of SHUV Lumi II, the correspondence with rhodopsin photointermediates breaks down and the next photointermediate, presumably including the G protein-activating species, is a mixture of protonated and unprotonated Schiff base photointermediate species.

  2. 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...

  3. 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...

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Areas and volumes for null cones

    CERN Document Server

    Grant, James D E

    2010-01-01

    Motivated by recent work of Choquet-Bruhat, Chrusciel, and Martin-Garcia, we prove monotonicity properties and comparison results for the area of slices of the null cone of a point in a Lorentzian manifold. We also prove volume comparison results for subsets of the null cone analogous to the Bishop-Gromov relative volume monotonicity theorem and Guenther's volume comparison theorem. We briefly discuss how these estimates may be used to control the null second fundamental form of slices of the null cone in Ricci-flat Lorentzian four-manifolds with null curvature bounded above.

  14. 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)

  15. Lifts of Convex Sets and Cone Factorizations

    OpenAIRE

    Gouveia, João; Parrilo, Pablo A.; 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 eleme...

  16. 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.

  17. 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...

  18. 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...

  19. 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.

  20. 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

  1. 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.

  2. Einstein constraints on a characteristic cone

    CERN Document Server

    Choquet-Bruhat, Yvonne; Martín-García, José M

    2010-01-01

    We analyse the Cauchy problem on a characteristic cone, including its vertex, for the Einstein equations in arbitrary dimensions. We use a wave map gauge, solve the obtained constraints and show gauge conservation.

  3. 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.

  4. 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...

  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. Coexpression of three middle wavelength-absorbing visual pigments in sexually dimorphic photoreceptors of the butterfly Colias erate

    NARCIS (Netherlands)

    Ogawa, Yuri; Awata, Hiroko; Wakakuwa, Motohiro; Kinoshita, Michiyo; Stavenga, Doekele G.; Arikawa, Kentaro

    2012-01-01

    The tiered ommatidia of the Eastern Pale Clouded yellow butterfly, Colias erate, contain nine photoreceptor cells, four of which contribute their rhabdomeral microvilli to the distal tier of the rhabdom. We analyzed the visual pigments and spectral sensitivities of these distal photoreceptors in bot

  7. Calcium homeostasis in photoreceptor cells of Drosophila mutants inaC and trp studied with the pupil mechanism

    NARCIS (Netherlands)

    Hofstee, CA; Stavenga, DG

    1996-01-01

    The light-driven pupil mechanism, consisting of an assembly of mobile pigment granules inside the photoreceptor cells, has been investigated by in vivo reflection microspectrophotometry in wild type (WT) Drosophila and in the photoreceptor mutants inaC and trp. The pupillary response of a dark-adapt

  8. 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.

  9. Metabolic signaling between photoreceptors and glial cells in the retina of the drone (Apis mellifera).

    Science.gov (United States)

    Brazitikos, P D; Tsacopoulos, M

    1991-12-13

    Experimental evidence showing metabolic interaction and signaling between photoreceptors-neurons and glial cells of the honeybee drone retina is presented. In this tissue [3H]2-deoxyglucose ([3H]2DG) in the dark and during repetitive light stimulation is phosphorylated to [3H]2-deoxyglucose-6P ([3H]2DG-6P) almost exclusively in the glial cells. Hence, stimulus-induced changes in the rate of formation of [3H]2DG-6P occurs predominantly in the glial cells. Repetitive stimulation of the photoreceptors with light flashes induced about a 47% rise in the rate of formation of [3H]2DG-6P in the glial cells and this effect is probably due to the activation of hexokinase. The potent inhibitor of glycolysis iodoacetic acid (IAA), inhibited this phosphorylation by about 75%. Probably this was largely due to an about 70% decrease of adenosine triphosphate (ATP). Exposure of the retina to IAA suppressed the transient rise in oxygen consumption (delta QO2) in the photoreceptors and subsequently the light-induced receptor potential. This indicates that the supply of a glycolytic substrate by glial cells to the photoreceptors is greatly reduced by IAA. Anoxia, by rapidly suppressing QO2, abolished the receptor potential of the photoreceptors and caused a rapid drop of about 50% in the ATP content of the retina. At the same time the formation of [3H]2DG-6P was inhibited by about 30%. This indicates that respiring photoreceptors send a metabolic signal to glial cells which is suppressed by anoxia. PMID:1815828

  10. 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...

  11. 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...

  12. 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...

  13. 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.

  14. Avian models in teratology and developmental toxicology.

    Science.gov (United States)

    Smith, Susan M; Flentke, George R; Garic, Ana

    2012-01-01

    The avian embryo is a long-standing model for developmental biology research. It also has proven utility for toxicology research both in ovo and in explant culture. Like mammals, avian embryos have an allantois and their developmental pathways are highly conserved with those of mammals, thus avian models have biomedical relevance. Fertile eggs are inexpensive and the embryo develops rapidly, allowing for high-throughput. The chick genome is sequenced and significant molecular resources are available for study, including the ability for genetic manipulation. The absence of a placenta permits the direct study of an agent's embryotoxic effects. Here, we present protocols for using avian embryos in toxicology research, including egg husbandry and hatch, toxicant delivery, and assessment of proliferation, apoptosis, and cardiac structure and function.

  15. Avian protection plan : Lostwood National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Lostwood National Wildlife Refuge (LNWR) initiated this Avian Protection Plan (APP) in 2003 to protect birds from potential electrocution hazards on the...

  16. 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...

  17. Crowding in the S-cone pathway.

    Science.gov (United States)

    Coates, Daniel R; Chung, Susana T L

    2016-05-01

    The spatial extent of interference from nearby object or contours (the critical spacing of "crowding") has been thoroughly characterized across the visual field, typically using high contrast achromatic stimuli. However, attempts to link this measure with known properties of physiological pathways have been inconclusive. The S-cone pathway, with its ease of psychophysical isolation and known anatomical characteristics, offers a unique tool to gain additional insights into crowding. In this study, we measured the spatial extent of crowding in the S-cone pathway at several retinal locations using a chromatic adaptation paradigm. S-cone crowding was evident and extensive, but its spatial extent changed less markedly as a function of retinal eccentricity than the extent found using traditional achromatic stimuli. However, the spatial extent agreed with that of low contrast achromatic stimuli matched for isolated resolvability. This suggests that common cortical mechanisms mediate the crowding effect in the S-cone and achromatic pathway, but contrast is an important factor. The low contrast of S-cone stimuli makes S-cone vision more acuity-limited than crowding-limited.

  18. 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 ...

  19. 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.

  20. Photonic Landau levels on cones

    Science.gov (United States)

    Schine, Nathan; Ryou, Albert; Gromov, Andrey; Sommer, Ariel; Simon, Jonathan

    2016-05-01

    We present the first experimental realization of a bulk magnetic field for optical photons. By using a non-planar ring resonator, we induce an image rotation on each round trip through the resonator. This results in a Coriolis/Lorentz force and a centrifugal anticonfining force, the latter of which is cancelled by mirror curvature. Using a digital micromirror device to control both amplitude and phase, we inject arbitrary optical modes into our resonator. Spatial- and energy- resolved spectroscopy tracks photonic eigenstates as residual trapping is reduced, and we observe photonic Landau levels as the eigenstates become degenerate. We show that there is a conical geometry of the resulting manifold for photon dynamics and present a measurement of the local density of states that is consistent with Landau levels on a cone. While our work already demonstrates an integer quantum Hall material composed of photons, we have ensured compatibility with strong photon-photon interactions, which will allow quantum optical studies of entanglement and correlation in manybody systems including fractional quantum Hall fluids.

  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. 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...

  3. 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

  4. 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.

  5. Down regulation of pRb in cultures of avian neuroretina cells promotes proliferation of reactive Müller-like cells and emergence of retinal stem/progenitors.

    Science.gov (United States)

    Marx, Maria; Lebuhotel, Céline; Laugier, Danielle; Chapelle, Audrey; Calothy, Georges; Saule, Simon

    2010-06-01

    The aim of this work was to define the role of pRb depletion in the proliferation and differentiation of avian retinoblasts in vitro. For this purpose vectors expressing pRb short hairpin RNA were used to deplete pRb in cultures of avian neuroretinal cells. Down regulation of pRb was observed by Western blot and quantification of nuclear pRb. Cell proliferation and differentiation were studied following BrdU labeling and immunostaining. Transfection significantly down-regulated pRb in neuroretinal cells. Long-term effect of pRb depletion mainly induced proliferation of epithelial-like cells that expressed markers of reactive Müller glial cells. A minority of these cells that survived passaging could be maintained as neurosphere-like aggregates with low pRb, not observed in control cultures. BrdU labeling followed by a two week chase showed the presence of cells still remained labelled, indicating low cell cycling. Under appropriate conditions, these aggregates differentiate in precursors of amacrine interneurons shown by the expression of AP2, in absence of the photoreceptors marker visinin and the late neuronal marker MAP2. Taken together these data show that decrease pRb level in cultures of avian neuroretinal cells promotes the emergence and proliferation of stem cell/progenitors from reactive-like Muller cells.

  6. Clinical Course, Genetic Etiology, and Visual Outcome in Cone and Cone-Rod Dystrophy

    NARCIS (Netherlands)

    Thiadens, Alberta A. H. J.; Phan, T. My Lan; Zekveld-Vroon, Renate C.; Leroy, Bart P.; van den Born, L. Ingeborgh; Hoyng, Carel B.; Klaver, Caroline C. W.; Roosing, Susanne; Pott, Jan-Willem R.; van Schooneveld, Mary J.; van Moll-Ramirez, Norka; van Genderen, Maria M.; Boon, Camiel J. F.; den Hollander, Anneke I.; Bergen, Arthur A. B.; De Baere, Elfride; Cremers, Frans P. M.; Lotery, Andrew J.

    2012-01-01

    Objective: To evaluate the clinical course, genetic etiology, and visual prognosis in patients with cone dystrophy (CD) and cone-rod dystrophy (CRD). Design: Clinic-based, longitudinal, multicenter study. Participants: Consecutive probands with CD (N = 98), CRD (N = 83), and affected relatives (N =

  7. Clinical course, genetic etiology, and visual outcome in cone and cone-rod dystrophy

    NARCIS (Netherlands)

    Thiadens, A.A.; Phan, T.M.; Zekveld-Vroon, R.C.; Leroy, B.P.; Born, L.I. van den; Hoyng, C.B.; Klaver, C.C.; Writing Committee for the Cone Disorders Study Group, C.; Roosing, S.; Pott, J.W.; Schooneveld, M.J. van; Moll-Ramirez, N. van; Genderen, M.M. van; Boon, C.J.F.; Hollander, A.I. den; Bergen, A.A.; Baere, E. de; Cremers, F.P.; Lotery, A.J.

    2012-01-01

    OBJECTIVE: To evaluate the clinical course, genetic etiology, and visual prognosis in patients with cone dystrophy (CD) and cone-rod dystrophy (CRD). DESIGN: Clinic-based, longitudinal, multicenter study. PARTICIPANTS: Consecutive probands with CD (N = 98), CRD (N = 83), and affected relatives (N =

  8. 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

  9. Angular and spectral sensitivity of fly photoreceptors. I. Integrated facet lens and rhabdomere optics

    NARCIS (Netherlands)

    Stavenga, D.G.

    2003-01-01

    Three optical components of a fly’s eye determine the angular sensitivity of the photoreceptors: the light diffracting facet lens, the wave-guiding rhabdomere and the light-absorbing visual pigment in the rhabdomere. How the integrated optical system of the fly eye shapes the angular sensitivity cur

  10. 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.

  11. 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.

  12. AA/12-lipoxygenase signaling contributes to inhibitory learning in Hermissenda Type B photoreceptors

    Directory of Open Access Journals (Sweden)

    Tony L Walker

    2010-08-01

    Full Text Available Conditioned inhibition (CI is a major category of associative learning that occurs when an organism learns that one stimulus predicts the absence of another. In addition to being important in its own right, CI is interesting because its occurrence implies that the organism has formed an association between stimuli that are non-coincident. In contrast to other categories of associative learning that are dependent upon temporal contiguity (pairings of stimuli, the neurobiology of CI is virtually unexplored. We have previously described a simple form of CI learning in Hermissenda, whereby animals’ phototactic behavior is increased by repeated exposures to explicitly unpaired (EU presentations of light and rotation. EU conditioning also produces characteristic reductions in the excitability and light response, and increases several somatic K+ currents in Type B photoreceptors. Type B photoreceptors are a major site of plasticity for classical conditioning in Hermissenda. Because arachidonic acid (AA and/or its metabolites open diverse K+ channels in many cell types, we examined the potential contribution of AA to CI. Our results indicate that AA contributes to one of the major effects of EU-conditioning on Type B photoreceptors: decreases in light-evoked spike activity. We find that AA increases the transient (IA somatic K+ current in Type B photoreceptors, further mimicking CI training. In addition, our results indicate that metabolism of AA by a 12-lipoxygenase enzyme is critical for these effects of AA, and further that 12-lipoxygenase metabolites are apparently generated during CI training.

  13. The genetics of some planthormones and photoreceptors in Arabidopsis thaliana (L.) Heynh

    NARCIS (Netherlands)

    Koornneef, M.

    1982-01-01

    This thesis describes the isolation and characterization in Arabidopsis thaliana (L.) Heynh. of induced mutants, deficient for gibberellins (GA's), abscisic acid (ABA) and photoreceptors.These compounds are known to regulate various facets of plant growth and differentiation, so mutants lacking one

  14. Photoreceptor spectral sensitivities of the Small White butterfly Pieris rapae crucivora interpreted with optical modeling

    NARCIS (Netherlands)

    Stavenga, Doekele G.; Arikawa, Kentaro

    2011-01-01

    The compound eye of the Small White butterfly, Pieris rapae crucivora, has four classes of visual pigments, with peak absorption in the ultraviolet, violet, blue and green, but electrophysiological recordings yielded eight photoreceptors classes: an ultraviolet, violet, blue, double-peaked blue, gre

  15. Light-dependent pigment migration in blowfly photoreceptors studied by in vivo CLSM

    NARCIS (Netherlands)

    Stavenga, DG; Leertouwer, HL; Smits, RP

    1996-01-01

    The light-dependent migration of pigment granules in the soma of fly photoreceptors has been studied in vivo with a fast confocal laser scanning microscope. Images as well as photometric measurements were obtained in the reflection and fluorescence modes. Measurements at the single cell level were p

  16. Förster resonance energy transfer as a tool to study photoreceptor biology

    Science.gov (United States)

    Hovan, Stephanie C.; Howell, Scott; Park, Paul S.-H.

    2010-11-01

    Vision is initiated in photoreceptor cells of the retina by a set of biochemical events called phototransduction. These events occur via coordinated dynamic processes that include changes in secondary messenger concentrations, conformational changes and post-translational modifications of signaling proteins, and protein-protein interactions between signaling partners. A complete description of the orchestration of these dynamic processes is still unavailable. Described in this work is the first step in the development of tools combining fluorescent protein technology, Förster resonance energy transfer (FRET), and transgenic animals that have the potential to reveal important molecular insights about the dynamic processes occurring in photoreceptor cells. We characterize the fluorescent proteins SCFP3A and SYFP2 for use as a donor-acceptor pair in FRET assays, which will facilitate the visualization of dynamic processes in living cells. We also demonstrate the targeted expression of these fluorescent proteins to the rod photoreceptor cells of Xenopus laevis, and describe a general method for detecting FRET in these cells. The general approaches described here can address numerous types of questions related to phototransduction and photoreceptor biology by providing a platform to visualize dynamic processes in molecular detail within a native context.

  17. Förster resonance energy transfer as a tool to study photoreceptor biology.

    Science.gov (United States)

    Hovan, Stephanie C; Howell, Scott; Park, Paul S-H

    2010-01-01

    Vision is initiated in photoreceptor cells of the retina by a set of biochemical events called phototransduction. These events occur via coordinated dynamic processes that include changes in secondary messenger concentrations, conformational changes and post-translational modifications of signaling proteins, and protein-protein interactions between signaling partners. A complete description of the orchestration of these dynamic processes is still unavailable. Described in this work is the first step in the development of tools combining fluorescent protein technology, Förster resonance energy transfer (FRET), and transgenic animals that have the potential to reveal important molecular insights about the dynamic processes occurring in photoreceptor cells. We characterize the fluorescent proteins SCFP3A and SYFP2 for use as a donor-acceptor pair in FRET assays, which will facilitate the visualization of dynamic processes in living cells. We also demonstrate the targeted expression of these fluorescent proteins to the rod photoreceptor cells of Xenopus laevis, and describe a general method for detecting FRET in these cells. The general approaches described here can address numerous types of questions related to phototransduction and photoreceptor biology by providing a platform to visualize dynamic processes in molecular detail within a native context.

  18. Sexual dimorphism of short-wavelength photoreceptors in the small white butterfly, Pieris rapae crucivora

    NARCIS (Netherlands)

    Arikawa, K; Wakakuwa, M; Qiu, XD; Kurasawa, M; Stavenga, DG; Qiu, Xudong

    2005-01-01

    The eyes of the female small white butterfly, Pieris rapae crucivora, are furnished with three classes of short-wavelength photoreceptors, with sensitivity peaks in the ultraviolet (UV) (lambda(max) = 360 nm), violet (V) (lambda max = 425 nm), and blue (B) (lambda(max) = 453 nm) wavelength range. An

  19. Temperature Dependence of Receptor Potential and Noise in Fly (Calliphora erythrocephala) Photoreceptor Cells

    NARCIS (Netherlands)

    Roebroek, J.G.H.; Tjonger, M. van; Stavenga, D.G.

    1990-01-01

    We investigated the effect of temperature on the response to light of photoreceptors of the blowfly Calliphora erythrocephala. The latency and the time-to-peak of the responses become shorter as the temperature increases; Q10 = 2.8 ± 0.6. The response amplitude is independent of the temperature in t

  20. Calcium transients in the rhabdomeres of dark- and light-adapted fly photoreceptor cells

    NARCIS (Netherlands)

    Oberwinkler, J; Stavenga, DG

    2000-01-01

    The light response of fly photoreceptor cells is modulated by changes in free Ca2+ concentration. Fly phototransduction and most processes regulating it take place in or very close to the rhabdomere. We therefore measured the kinetics and the absolute values of the free Ca2+ concentration in the rha

  1. Angular sensitivity of blowfly photoreceptors : intracellular measurements and wave-optical predictions

    NARCIS (Netherlands)

    Smakman, J.G.J.; Hateren, J.H. van; Stavenga, D.G.

    1984-01-01

    The angular sensitivity of blowfly photoreceptors was measured in detail at wavelengths λ = 355, 494 and 588 nm. The measured curves often showed numerous sidebands, indicating the importance of diffraction by the facet lens. The shape of the angular sensitivity profile is dependent on wavelength. T

  2. 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.

  3. 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.

  4. 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

    2016-01-01

    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. PMID:26935401

  5. An expanded set of photoreceptors in the Eastern Pale Clouded Yellow butterfly, Colias erate

    NARCIS (Netherlands)

    Pirih, Primoz; Arikawa, Kentaro; Stavenga, Doekele G.; Pirih, Primož

    2010-01-01

    We studied the spectral and polarisation sensitivities of photoreceptors of the butterfly Colias erate by using intracellular electrophysiological recordings and stimulation with light pulses. We developed a method of response waveform comparison (RWC) for evaluating the effective intensity of the l

  6. 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

  7. 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 ...

  8. 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.

  9. Gibberellin and auxin influence the diurnal transcription pattern of photoreceptor genes via CRY1a in tomato.

    Directory of Open Access Journals (Sweden)

    Paolo Facella

    Full Text Available 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/PRINCIPAL FINDINGS: In this work, we investigated the molecular effects of exogenous phyto-hormones to photoreceptor gene transcripts of tomato wt, as well as transgenic and mutant lines with altered cryptochromes, by monitoring day/night transcript oscillations. GA and auxin alter the diurnal expression level of different photoreceptor genes in tomato, especially in mutants that lack a working form of cryptochrome 1a: in those mutants the expression of some (IAA or most (GA photoreceptor genes is down regulated by these hormones. CONCLUSIONS/SIGNIFICANCE: Our results highlight the presence of molecular relationships among cryptochrome 1a protein, hormones, and photoreceptors' gene expression in tomato, suggesting that manipulation of cryptochromes could represent a good strategy to understand in greater depth the role of phyto-hormones in the plant photoperceptive mechanism.

  10. 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.

  11. 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.

  12. 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)

  13. Resonance in a Cone-Topped Tube

    Directory of Open Access Journals (Sweden)

    Angus Cheng-Huan Chia

    2011-06-01

    Full Text Available The relationship between ratio of the upper opening diameter of a cone-topped cylinder to the cylinder diameter,and the ratio of the length of the air column to resonant period was examined. Plastic cones with upper openings ranging from 1.3 cm to 3.6 cm and tuning forks with frequencies ranging from 261.6 Hz to 523.3 Hz were used. The transition from a standing wave in a cylindrical column to a Helmholtz-type resonance in a resonant cavity with a narrow opening was observed.

  14. Algebraic boundaries of Hilbert's SOS cones

    CERN Document Server

    Blekherman, Grigoriy; Ottem, John Christian; Ranestad, Kristian; Sturmfels, Bernd

    2011-01-01

    We study the geometry underlying the difference between non-negative polynomials and sums of squares. The hypersurfaces that discriminate these two cones for ternary sextics and quaternary quartics are shown to be Noether-Lefschetz loci of K3 surfaces. The projective duals of these hypersurfaces are defined by rank constraints on Hankel matrices. We compute their degrees using numerical algebraic geometry, thereby verifying results due to Maulik and Pandharipande. The non-SOS extreme rays of the two cones of non-negative forms are parametrized respectively by the Severi variety of plane rational sextics and by the variety of quartic symmetroids.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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).

  1. 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...

  2. 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...

  3. 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 ...

  4. 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

  5. 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.

  6. 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

  7. Geodesics in the space of K\\"ahler cone metrics

    CERN Document Server

    Calama, Simone

    2012-01-01

    In this paper, we prove the existence and uniqueness of the weak cone geodesics in the space of K\\"ahler cone metrics by solving the singular, homogeneous complex Monge-Amp\\`{e}re equation. As an application, we prove the metric space structure of the appropriate subspace of the space of K\\"ahler cone metrics.

  8. 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.

  9. Economic effects of avian influenza on egg producers in Turkey

    Directory of Open Access Journals (Sweden)

    V Demircan

    2009-09-01

    Full Text Available 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 previous levels, farms experienced significantly reduced incomes during the avian influenza episode. While net income and profit margin were found to be negative in all three farm groups during the avian influenza period, only group I showed economic loss prior to avian influenza. Average net income per group was -19,576.14, -39,810.11, and -112,035.33 YTL respectively during the avian influenza outbreak, compared with prior incomes of -5,665.51, 8,422.92, and 16,3873.71 YTL (1 USD=1.43 YTL. The profit margin per egg during avian influenza was -0.029, -0.016, -0.010 YTL in group I, II, III, respectively, as compared to -0.007, 0.003, and 0.014 YTL/egg before avian influenza. It was found that, whereas larger farms were more profitable than small farms prior to the avian influenza period, larger farms suffered greater economic losses than small farms during avian influenza outbreak in the participating farms.

  10. Cone beam CT, wat moet ik ermee?

    NARCIS (Netherlands)

    R. Hoogeveen

    2013-01-01

    De cone beam-ct-scan (cbct-scan) maakt een opmars in de tandheelkunde vanwege de toegevoegde waarde van de derde dimensie in de diagnostiek. Deze extra informatie wordt verkregen ten koste van een hogere stralenbelasting en een daarmee gepaard gaand hoger risico voor de patiënt. Om de clinicus te he

  11. 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

  12. Lagrangian duality and cone convexlike functions

    NARCIS (Netherlands)

    J.B.G. Frenk (Hans); G. Kassay

    2005-01-01

    textabstractIn this paper we will show that the closely K-convexlike vector-valued functions with K Rm a nonempty convex cone and related classes of vector-valued functions discussed in the literature arise naturally within the theory of biconjugate functions applied to the Lagrangian perturbation s

  13. Cone beam computed tomography in veterinary dentistry

    NARCIS (Netherlands)

    B. van Thielen; F. Siguenza; B. Hassan

    2012-01-01

    The purpose of this study was to assess the feasibility of cone beam computed tomography (CBCT) in imaging dogs and cats for diagnostic dental veterinary applications. CBCT scans of heads of six dogs and two cats were made. Dental panoramic and multi-planar reformatted (MPR) para-sagittal reconstruc

  14. 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.

  15. 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...

  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. 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.

  19. Short-term psychosocial stress protects photoreceptors from damage via corticosterone-mediated activation of the AKT pathway.

    Science.gov (United States)

    Forkwa, Tembei K; Neumann, Inga D; Tamm, Ernst R; Ohlmann, Andreas; Reber, Stefan O

    2014-02-01

    Apoptotic death of photoreceptors in hereditary retinal degenerations can be prevented by neuroprotective molecules. Here, we report that adrenal glucocorticoids (GC) released during psychosocial stress protect photoreceptors from apoptosis after light damage. Psychosocial stress is known to be the main type of stressor humans are exposed to and was induced here in mice by 10h of chronic subordinate colony housing (CSC). Photoreceptor damage was generated by subsequent exposure to white light. Short-term psychosocial stress prior to illumination significantly reduced the number of apoptotic photoreceptors, an effect that was absent in adrenalectomized (ADX) mice. The neuroprotective effect was completely restored in ADX mice substituted with GC. Moreover, phosphorylation of retinal AKT increased following CSC or exogenous GC treatment, an effect that was again absent in ADX mice exposed to CSC. Finally, inhibition of AKT signaling with triciribine blocked the stress- and GC-mediated neuroprotective effects on photoreceptors. In summary, we provide evidence that 1) short-term psychosocial stress protects photoreceptors from light-induced damage and 2) the protective effect is most likely mediated by GC-induced activation of the AKT signaling pathway.

  20. Cav1.4 L-Type Calcium Channels Contribute to Calpain Activation in Degenerating Photoreceptors of rd1 Mice.

    Directory of Open Access Journals (Sweden)

    Christian Schön

    Full Text Available 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.

  1. Photoactivation mechanisms of flavin-binding photoreceptors revealed through ultrafast spectroscopy and global analysis methods.

    Science.gov (United States)

    Mathes, Tilo; van Stokkum, Ivo H M; Kennis, John T M

    2014-01-01

    Flavin-binding photoreceptor proteins use the isoalloxazine moiety of flavin cofactors to absorb light in the blue/UV-A wavelength region and subsequently translate it into biological information. The underlying photochemical reactions and protein structural dynamics are delicately tuned by the protein environment and represent fundamental reactions in biology and chemistry. Due to their photo-switchable nature, these proteins can be studied efficiently with laser-flash induced transient absorption and emission spectroscopy with temporal precision down to the femtosecond time domain. Here, we describe the application of both visible and mid-IR ultrafast transient absorption and time-resolved fluorescence methods in combination with sophisticated global analysis procedures to elucidate the photochemistry and signal transduction of BLUF (Blue light receptors using FAD) and LOV (Light oxygen voltage) photoreceptor domains.

  2. 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)

  3. 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...

  4. Fossil avian eggshell preserves ancient DNA

    DEFF Research Database (Denmark)

    Oskam, Charlotte L; Haile, James; McLay, Emma;

    2010-01-01

    Owing to exceptional biomolecule preservation, fossil avian eggshell has been used extensively in geochronology and palaeodietary studies. Here, we show, to our knowledge, for the first time that fossil eggshell is a previously unrecognized source of ancient DNA (aDNA). We describe the successful...

  5. 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.

  6. 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.

  7. 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...

  8. Measuring Steroid Hormones in Avian Eggs

    NARCIS (Netherlands)

    Engelhardt, Nikolaus von; Groothuis, Ton G.G.

    2005-01-01

    Avian eggs contain substantial levels of various hormones of maternal origin and have recently received a lot of interest, mainly from behavioral ecologists. These studies strongly depend on the measurement of egg hormone levels, but the method of measuring these levels has received little attention

  9. 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

  10. 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.

  11. 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.

  12. Serological diagnosis of avian influenza in poultry

    DEFF Research Database (Denmark)

    Comin, Arianna; Toft, Nils; Stegeman, Arjan;

    2013-01-01

    Background The serological diagnosis of avian influenza (AI) can be performed using different methods, yet the haemagglutination inhibition (HI) test is considered the gold standard' for AI antibody subtyping. Although alternative diagnostic assays have been developed, in most cases, their accuracy...

  13. Evolutionary dynamics of human and avian metapneumoviruses

    NARCIS (Netherlands)

    M.T. de Graaf (Marieke); A.D.M.E. Osterhaus (Ab); R.A.M. Fouchier (Ron); E.C. Holmes (Edward)

    2008-01-01

    textabstractHuman (HMPV) and avian (AMPV) metapneumoviruses are closely related viruses that cause respiratory tract illnesses in humans and birds, respectively. Although HMPV was first discovered in 2001, retrospective studies have shown that HMPV has been circulating in humans for at least 50 year

  14. Are we ready for the avian flu?

    Science.gov (United States)

    Huff, Charlotte

    2006-01-01

    It may be tempting to dismiss headlines about a potential avian flu pandemic as "the sky is falling" sensationalism, but experts continue to warn that the disease is likely to show up here in the not-too-distant future. What must hospitals do to prepare for a sudden influx of patients and other huge demands such a crisis would create? PMID:16485802

  15. Experimental induced avian E. coli salpingitis

    DEFF Research Database (Denmark)

    Olsen, Rikke Heidemann; Thøfner, Ida; Pors, Susanne Elisabeth;

    2016-01-01

    manifestations or from the cloacae of a healthy chicken. The virulence potential of the strains were evaluated in an avian experimental model for ascending infections, and experiments were conducted in both layers and broiler breeders. The clinical outcome of infection was highly depending on the challenge...

  16. 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...

  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. 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...

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. Distinct roles of Bazooka and Stardust in the specification of Drosophila photoreceptor membrane architecture.

    Science.gov (United States)

    Hong, Yang; Ackerman, Larry; Jan, Lily Yeh; Jan, Yuh-Nung

    2003-10-28

    Photoreceptors form during Drosophila pupal development and acquire elaborate membrane structures, including the rhabdomeres and stalk membranes. Here, we show that the development of these cellular structures involves two distinct processes: the establishment of apical-basal polarity that requires Bazooka (Baz), and the regionalization of apical membrane into stalk membranes and rhabdomeres that requires Stardust (Sdt). In the absence of Baz, the apical-basal polarity is compromised in early pupal photoreceptors, and no identifiable apical membrane domain is formed. Sdt, in contrast, plays a more limited role in apical-basal polarity but is essential for the proper localization of transmembrane protein Crumbs (Crb), known to be required in the biogenesis of stalk membrane. Loss of Sdt causes strong defects in stalk membrane and rhabdomere resembling crb mutant phenotype. Thus, proteins required for establishing the early embryonic epithelial polarity are used later for the morphogenesis of photoreceptors, with Baz and Sdt functioning in different aspects of the formation of the apical-basal cellular architecture.

  5. 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.

  6. Novel potassium channels encoded by the Shaker locus in Drosophila photoreceptors.

    Science.gov (United States)

    Hardie, R C; Voss, D; Pongs, O; Laughlin, S B

    1991-03-01

    The Shaker gene, responsible for A-type potassium channels in Drosophila muscle, encodes a large family of transcripts capable of generating a variety of kinetically distinct A channels when expressed in oocytes. We describe a distinct class of A channel encoded by the Shaker gene in a novel preparation of dissociated Drosophila photoreceptors. Whole-cell recordings reveal a rapidly inactivating A current that is absent in Shaker mutants and that can be readily isolated in cell-attached patches. Although very similar to their muscle counterparts, the photoreceptor A channels show a striking 40-50 mV negative shift in their voltage-operating range. Two mutations (ShE62 and T(1;Y)W32), which exclude only certain classes of Shaker transcripts, were used to show that photoreceptor A channels are encoded by multiple transcripts distinct from those encoding muscle A channels, while PCR techniques identified four transcripts (ShA1, ShA2, ShG1, and ShG2) in mRNA from dissected retina. PMID:2001287

  7. Rotenone induces degeneration of photoreceptors and impairs the dopaminergic system in the rat retina.

    Science.gov (United States)

    Esteve-Rudd, Julián; Fernández-Sánchez, Laura; Lax, Pedro; De Juan, Emilio; Martín-Nieto, José; Cuenca, Nicolás

    2011-10-01

    Rotenone is a widely used pesticide and a potent inhibitor of mitochondrial complex I (NADH-quinone reductase) that elicits the degeneration of dopaminergic neurons and thereby the appearance of a parkinsonian syndrome. Here we have addressed the alterations induced by rotenone at the functional, morphological and molecular levels in the retina, including those involving both dopaminergic and non-dopaminergic retinal neurons. Rotenone-treated rats showed abnormalities in equilibrium, postural instability and involuntary movements. In their outer retina we observed a loss of photoreceptors, and a reduced synaptic connectivity between those remaining and their postsynaptic neurons. A dramatic loss of mitochondria was observed in the inner segments, as well as in the axon terminals of photoreceptors. In the inner retina we observed a decrease in the expression of dopaminergic cell molecular markers, including loss of tyrosine hydroxylase immunoreactivity, associated with a reduction of the dopaminergic plexus and cell bodies. An increase in immunoreactivity of AII amacrine cells for parvalbumin, a Ca(2+)-scavenging protein, was also detected. These abnormalities were accompanied by a decrease in the amplitude of scotopic and photopic a- and b-waves and an increase in the b-wave implicit time, as well as by a lower amplitude and greater latency in oscillatory potentials. These results indicate that rotenone induces loss of vision by promoting photoreceptor cell death and impairment of the dopaminergic retinal system.

  8. 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...

  9. 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

  10. k-cones and kirigami metamaterials

    Science.gov (United States)

    Seffen, Keith A.

    2016-09-01

    We are inspired by the tensile buckling of a thin sheet with a slit to create a foldable planar metamaterial. The buckled shape comprises two pairs of identical e-cones connected to the slit, which we refer to as a k-cone. We approximate this shape as discrete vertices that can be folded out of plane as the slit is pulled apart. We determine their kinematics and we calculate generic shape properties using a simple elastic model of the folded shape. We then show how the folded sheet may be tessellated as a unit cell within a larger sheet, which may be constructed a priori by cutting and folding the latter in a regular way, in order to form a planar kirigami structure with a single degree of freedom.

  11. 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...

  12. 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.

  13. Wavefronts and Light Cones for Kerr Spacetimes

    CERN Document Server

    Frutos-Alfaro, Francisco; Mueller, Thomas; Adis, Daria

    2014-01-01

    We investigate the light propagation by means of simulations of wavefronts and light cones for Kerr spacetimes. Simulations of this kind give us a new insight to better understand the light propagation in presence of massive rotating black holes. A relevant result is that wavefronts are back scattered with winding around the black hole. To generate these visualizations, an interactive computer program with a graphical user interface, called JWFront, was written in Java.

  14. 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.

  15. Developmental changes in biophysical properties of photoreceptors in the common water strider (Gerris lacustris): better performance at higher cost.

    Science.gov (United States)

    Frolov, Roman; Weckström, Matti

    2014-08-15

    Although the dependence of invertebrate photoreceptor biophysical properties on visual ecology has already been investigated in some cases, developmental aspects have largely been ignored due to the general research emphasis on holometabolous insects. Here, using the patch-clamp method, we examined changes in biophysical properties and performance of photoreceptors in the common water strider Gerris lacustris during postembryonic development. We identified two types of peripheral photoreceptors, green and blue sensitive. Whole cell capacitance (a measure of cell size) of blue photoreceptors was significantly higher than the capacitance of green photoreceptors (69 ± 20 vs. 43 ± 12 pF, respectively). Most of the measured morphological and biophysical parameters changed with development. Photoreceptor capacitance increased progressively and was positively correlated with sensitivity to light, magnitudes and densities of light-induced (LIC) and delayed rectifier K(+) (IDR) currents, membrane corner frequency, and maximal information rate [Spearman rank correlation coefficients: 0.70 (sensitivity), 0.79 (LIC magnitude), 0.79 (IDR magnitude), 0.48 (corner frequency), and 0.57 (information rate)]. Transient K(+) current increased to a smaller extent, while its density decreased. We found no significant changes in the properties of single photon responses or levels of light-induced depolarization, the latter indicating a balanced channelome expansion associated with IDR expression. However, the dramatic ∼7.6-fold increase in IDR from first instars to adults indicated a development-related rise in the metabolic cost of information. In conclusion, this study provides novel insights into functional photoreceptor adaptations with development and illustrates remarkable variability in patterns of postembryonic retinal development in hemimetabolous insects with dissimilar visual ecologies and behaviors.

  16. 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...

  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 =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.

  18. Cusp formation in drops inside Taylor cones

    Science.gov (United States)

    Marin, Alvaro G.; Loscertales, Ignacio G.; Barrero, Antonio

    2005-11-01

    Here, we report the formation of cusp in insulating drops inside compound Taylor cones. The action of the electrical shear stress acting on the outer interface, which is transmitted by viscous forces inside the Taylor cone, tends to deform the drop of insulating liquid placed inside. For appropriate values of the capillary number, the insulating drop develops a steady cusp angle which depends on both the capillary number and the conducting to insulating viscosity ratio. A self-similar analysis has been developed to qualitatively describe the flow inside these compounds Taylor cones. Any perturbation of the cusp gives rise to an intermittent emission of tiny droplets; this effect may recall the tip-streaming observed by G.I. Taylor in his four-roll mill device. This emission can be stabilized by an appropriate control of the injected flow rate of the insulating liquid. When the capillary number increases, the cusped interface turns into a spout which flows coated by the conducting liquid forming the electrified coaxial jet which has been successfully employed for the production of nanocapsules, coaxial nanofibers and nanotubes (Science 295, n. 5560, 1695, 2002; JACS 126, 5376, 2004).

  19. 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

  20. 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...

  1. 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...

  2. 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, ...

  3. 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.

  4. 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.

  5. Seasonal change in the avian hippocampus.

    Science.gov (United States)

    Sherry, David F; MacDougall-Shackleton, Scott A

    2015-04-01

    The hippocampus plays an important role in cognitive processes, including memory and spatial orientation, in birds. The hippocampus undergoes seasonal change in food-storing birds and brood parasites, there are changes in the hippocampus during breeding, and further changes occur in some species in association with migration. In food-storing birds, seasonal change in the hippocampus occurs in fall and winter when the cognitively demanding behaviour of caching and retrieving food occurs. The timing of annual change in the hippocampus of food-storing birds is quite variable, however, and appears not to be under photoperiod control. A variety of factors, including cognitive performance, exercise, and stress may all influence seasonal change in the avian hippocampus. The causal processes underlying seasonal change in the avian hippocampus have not been extensively examined and the more fully described hormonal influences on the mammalian hippocampus may provide hypotheses for investigating the control of hippocampal seasonality in birds.

  6. 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...

  7. 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...

  8. 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 ...

  9. 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 ...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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 ...

  16. 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

  17. Pulsar average waveforms and hollow cone beam models

    Science.gov (United States)

    Backer, D. C.

    1975-01-01

    An analysis of pulsar average waveforms at radio frequencies from 40 MHz to 15 GHz is presented. The analysis is based on the hypothesis that the observer sees one cut of a hollow-cone beam pattern and that stationary properties of the emission vary over the cone. The distributions of apparent cone widths for different observed forms of the average pulse profiles (single, double/unresolved, double/resolved, triple and multiple) are in modest agreement with a model of a circular hollow-cone beam with random observer-spin axis orientation, a random cone axis-spin axis alignment, and a small range of physical hollow-cone parameters for all objects.

  18. Tantalum cones and bone defects in revision total knee arthroplasty.

    Science.gov (United States)

    Boureau, F; Putman, S; Arnould, A; Dereudre, G; Migaud, H; Pasquier, G

    2015-04-01

    Management of bone loss is a major challenge in revision total knee arthroplasty (TKA). The development of preformed porous tantalum cones offers new possibilities, because they seem to have biological and mechanical qualities that facilitate osseointegration. Compared to the original procedure, when metaphyseal bone defects are too severe, a single tantalum cone may not be enough and we have developed a technique that could extend the indications for this cone in these cases. We used 2 cones to fill femoral bone defects in 7 patients. There were no complications due to wear of the tantalum cones. Radiological follow-up did show any migration or loosening. The short-term results confirm the interest of porous tantalum cones and suggest that they can be an alternative to allografts or megaprostheses in case of massive bone defects.

  19. 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.

  20. 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.

  1. 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)

  2. 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...

  3. 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.

  4. 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

  5. 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.

  6. Dynamics on the cone: Closed orbits and superintegrability

    Energy Technology Data Exchange (ETDEWEB)

    Brihaye, Y. [Department of Theoretical and Mathematical Physics, University of Mons, 20, Place du Parc, B7000 Mons (Belgium); Kosiński, P., E-mail: pkosinsk@uni.lodz.pl [Department of Theoretical Physics and Computer Science, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Maślanka, P., E-mail: pmaslan@uni.lodz.pl [Department of Theoretical Physics and Computer Science, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland)

    2014-05-15

    The generalization of Bertrand’s theorem to the case of the motion of point particle on the surface of a cone is presented. The superintegrability of such models is discussed. The additional integrals of motion are analysed for the case of Kepler and harmonic oscillator potentials. -- Highlights: •Bertrand’s theorem is generalized to the case of the motion on a cone. •The superintegrability of the dynamics on a cone is discussed. •The W-algebra of integrals of motion for Kepler and harmonic oscillator problems on a cone is derived.

  7. Dynamical Structure of the Fields in the Light Cone Coordinates

    CERN Document Server

    Kargar, Kianoosh

    2016-01-01

    It is well-known that additional constraints emerge in light cone coordinates. We enumerate the number of physical modes in light cone coordinates and compare it with conventional coordinates. We show that the number of Schrodinger modes is divided by two in light cone coordinates. We study the effect of this reduction in the number ladder operators acting on physical states of a system. We analyse the scaler, spinor and vector field theories carefully to see the effect of changes in the dynamical structure of these theories from the view point of the reduction of Schrodinger modes in light-cone coordinates.

  8. The trip of the tip: understanding the growth cone machinery.

    Science.gov (United States)

    Lowery, Laura Anne; Van Vactor, David

    2009-05-01

    The central component in the road trip of axon guidance is the growth cone, a dynamic structure that is located at the tip of the growing axon. During its journey, the growth cone comprises both 'vehicle' and 'navigator'. Whereas the 'vehicle' maintains growth cone movement and contains the cytoskeletal structural elements of its framework, a motor to move forward and a mechanism to provide traction on the 'road', the 'navigator' aspect guides this system with spatial bias to translate environmental signals into directional movement. The understanding of the functions and regulation of the vehicle and navigator provides new insights into the cell biology of growth cone guidance.

  9. Fractional quantum Hall states of bosons on cones

    CERN Document Server

    Wu, Ying-Hai; Sreejith, G J

    2016-01-01

    Motivated by a recent experiment which synthesizes Landau levels for photons on cones (Schine {\\em et al.}, arXiv: 1511.07381), and more generally the interest in understanding gravitational responses of quantum Hall systems, we study fractional quantum Hall states of bosons on cones. We construct several trial wave functions and compare them with exact diagonalization results. The tip of a cone is a localized geometrical defect with singular curvature around which excessive charges accumulate. We study the density profiles of some states on cones and show that the excessive charges agree with analytical predictions.

  10. Muller cell reactivity in response to photoreceptor degeneration in rats with defective polycystin-2.

    Directory of Open Access Journals (Sweden)

    Stefanie Vogler

    Full Text Available BACKGROUND: Retinal degeneration in transgenic rats that express a mutant cilia gene polycystin-2 (CMV-PKD2(1/703HA is characterized by initial photoreceptor degeneration and glial activation, followed by vasoregression and neuronal degeneration (Feng et al., 2009, PLoS One 4: e7328. It is unknown whether glial activation contributes to neurovascular degeneration after photoreceptor degeneration. We characterized the reactivity of Müller glial cells in retinas of rats that express defective polycystin-2. METHODS: Age-matched Sprague-Dawley rats served as control. Retinal slices were immunostained for intermediate filaments, the potassium channel Kir4.1, and aquaporins 1 and 4. The potassium conductance of isolated Müller cells was recorded by whole-cell patch clamping. The osmotic swelling characteristics of Müller cells were determined by superfusion of retinal slices with a hypoosmotic solution. FINDINGS: Müller cells in retinas of transgenic rats displayed upregulation of GFAP and nestin which was not observed in control cells. Whereas aquaporin-1 labeling of photoreceptor cells disappeared along with the degeneration of the cells, aquaporin-1 emerged in glial cells in the inner retina of transgenic rats. Aquaporin-4 was upregulated around degenerating photoreceptor cells. There was an age-dependent redistribution of Kir4.1 in retinas of transgenic rats, with a more even distribution along glial membranes and a downregulation of perivascular Kir4.1. Müller cells of transgenic rats displayed a slight decrease in their Kir conductance as compared to control. Müller cells in retinal tissues from transgenic rats swelled immediately under hypoosmotic stress; this was not observed in control cells. Osmotic swelling was induced by oxidative-nitrosative stress, mitochondrial dysfunction, and inflammatory lipid mediators. INTERPRETATION: Cellular swelling suggests that the rapid water transport through Müller cells in response to osmotic stress

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. Multiple photoreceptor systems control the swim pacemaker activity in box jellyfish

    DEFF Research Database (Denmark)

    Garm, Anders Lydik; Mori, S.

    2009-01-01

    Like all other cnidarian medusae, box jellyfish propel themselves through the water by contracting their bell-shaped body in discrete swim pulses. These pulses are controlled by a swim pacemaker system situated in their sensory structures, the rhopalia. Each medusa has four rhopalia each...... with a similar set of six eyes of four morphologically different types. We have examined how each of the four eye types influences the swim pacemaker. Multiple photoreceptor systems, three of the four eye types, plus the rhopalial neuropil, affect the swim pacemaker. The lower lens eye inhibits the pacemaker...

  16. 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

  17. 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

  18. 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.

  19. Coning-off CAT(0) cube complexes

    OpenAIRE

    Genevois, Anthony

    2016-01-01

    In this paper, we study the geometry of cone-offs of CAT(0) cube complexes over a family of combinatorially convex subcomplexes, with an emphasis on their Gromov-hyperbolicity. A first application gives a direct cubical proof of the characterization of the (strong) relative hyperbolicity of right-angled Coxeter groups, which is a particular case of a result due to Behrstock, Caprace and Hagen. A second application gives the acylindrical hyperbolicity of $C'(1/4)-T(4)$ small cancellation quoti...

  20. Coexpression of two visual pigments in a photoreceptor causes an abnormally broad spectral sensitivity in the eye of the butterfly Papilio xuthus

    NARCIS (Netherlands)

    Arikawa, K; Mizuno, S; Kinoshita, M; Stavenga, DG

    2003-01-01

    The compound eye of the butterfly Papilio xuthus consists of three different types of ommatidia, each containing nine photoreceptor cells (R1 - R9). We have found previously that the R5 - R8 photoreceptors of type II ommatidia coexpress two different mRNAs, encoding opsins of green- and orange-red-a

  1. Microcomputed tomography and shock microdeformation studies on shatter cones

    Science.gov (United States)

    Zaag, Patrice Tristan; Reimold, Wolf Uwe; Hipsley, Christy Anna

    2016-08-01

    One of the aspects of impact cratering that are still not fully understood is the formation of shatter cones and related fracturing phenomena. Yet, shatter cones have been applied as an impact-diagnostic criterion for decades without the role of shock waves and target rock defects in their formation having been elucidated ever. We have tested the application of the nondestructive microcomputed tomography (μCT) method to visualize the interior of shatter cones in order to possibly resolve links between fracture patterns and shatter cone surface features (striations and intervening "valleys"). Shatter-coned samples from different impact sites and in different lithologies were investigated for their μCT suitability, with a shatter cone in sandstone from the Serra da Cangalha impact structure (Brazil) remaining as the most promising candidate because of the fracture resolution achieved. To validate the obtained CT data, the scanned specimen was cut into three orthogonal sets of thin sections. Scans with 13 μm resolution were obtained. μCT scans and microscopic analysis unraveled an orientation of subplanar fractures and related fluid inclusion trails, and planar fracture (PF) orientations in the interior of shatter cones. Planar deformation features (PDF) were observed predominantly near the shatter cone surface. Previously undescribed varieties of feather features (FF), in the form of lamellae emanating from curviplanar and curved fractures, as well as an "arrowhead"-like FF development with microlamellae originating from both sides of a PF, were observed. The timing of shatter cone formation was investigated by establishing temporal relations to the generation of various shock microscopic effects. Shatter cones are, thus, generated post- or syn-formation of PF, FF, subplanar fractures, and PDF. The earliest possible time for shatter cone formation is during the late stage of the compressional phase, that is, shock wave passage, of an impact event.

  2. Ontogeny of avian thermoregulation from a neural point of view

    NARCIS (Netherlands)

    Baarendse, P.J.J.; Debonne, M.; Decuypere, M.P.; Kemp, B.; Brand, van den H.

    2007-01-01

    The ontogeny of thermoregulation differs among (avian) species, but in all species both neural and endocrinological processes are involved. In this review the neural processes in ontogeny of thermoregulation during the prenatal and early postnatal phase are discussed. Only in a few avian species (ch

  3. 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.

  4. Comparative genomics reveals insights into avian genome evolution and adaptation

    DEFF Research Database (Denmark)

    Zhang, Guojie; Li, Cai; Li, Qiye;

    2014-01-01

    Birds are the most species-rich class of tetrapod vertebrates and have wide relevance across many research fields. We explored bird macroevolution using full genomes from 48 avian species representing all major extant clades. The avian genome is principally characterized by its constrained size, ...

  5. 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.

  6. 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.

  7. 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...

  8. Morphologic evidence for differentiation of pinealocytes from photoreceptor cells in the adult noctule bat (Nyctalus noctula, Schreber).

    Science.gov (United States)

    Pevet, P; Ariëns Kappers, J; Voûte, A M

    1977-07-26

    An electron microscopical investigation of the pineal gland of the adult noctule bat revealed the presence of some peculiar ciliary derivatives, similar to the club-shaped outer segment of rudimentary photoreceptor cells in the pineal organ of nonmammalian vertebrates. The pinealocytes of population I can be classified in several morphological types, one of them displaying morphological features resembling those of rudimentary photoreceptor cells. These results reconfirm the concept of the sensory cell line in the vertebrate pineal organ. The question whether the pinealocytes of population II belong to the same sensory cell line is discussed.

  9. 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...

  10. Avian influenza in shorebirds: experimental infection of ruddy turnstones (Arenaria interpres) with avian influenza virus

    Science.gov (United States)

    Hall, Jeffrey S.; Krauss, Scott; Franson, J. Christian; TeSlaa, Joshua L.; Nashold, Sean W.; Stallknecht, David E.; Webby, Richard J.; Webster, Robert G.

    2013-01-01

    Background: Low pathogenic avian influenza viruses (LPAIV) have been reported in shorebirds, especially at Delaware Bay, USA, during spring migration. However, data on patterns of virus excretion, minimal infectious doses, and clinical outcome are lacking. The ruddy turnstone (Arenaria interpres) is the shorebird species with the highest prevalence of influenza virus at Delaware Bay. Objectives: The primary objective of this study was to experimentally assess the patterns of influenza virus excretion, minimal infectious doses, and clinical outcome in ruddy turnstones. Methods: We experimentally challenged ruddy turnstones using a common LPAIV shorebird isolate, an LPAIV waterfowl isolate, or a highly pathogenic H5N1 avian influenza virus. Cloacal and oral swabs and sera were analyzed from each bird. Results: Most ruddy turnstones had pre-existing antibodies to avian influenza virus, and many were infected at the time of capture. The infectious doses for each challenge virus were similar (103·6–104·16 EID50), regardless of exposure history. All infected birds excreted similar amounts of virus and showed no clinical signs of disease or mortality. Influenza A-specific antibodies remained detectable for at least 2 months after inoculation. Conclusions: These results provide a reference for interpretation of surveillance data, modeling, and predicting the risks of avian influenza transmission and movement in these important hosts.

  11. Infection of Avian Pox Virus in Oriental Turtle-Doves

    Directory of Open Access Journals (Sweden)

    Kyung-Yeon Eo1, Young-Hoan Kim2, Kwang-Hyun Cho3, Jong-Sik Jang4, Tae-Hwan Kim5, Dongmi Kwak5 and Oh-Deog Kwon5*

    2011-10-01

    Full Text Available Three Oriental Turtle-doves (Streptopelia orientalis exhibiting lethargy, dyspnea, poor physical condition, and poor flight endurance, were rescued and referred to the Animal Health Center, Seoul Zoo, Korea. The doves had wart-like lesions on the legs and head. All of them died the following day after arrival, with the exception of one that survived for 6 days. Diphtheritic membranes on the tongue and oral mucosa were apparent at necropsy. Avian pox virus infection was suspected based on the proliferative skin lesions and oral diphtheritic lesions. Infection of the avian pox virus was confirmed by PCR using primers specific to the 4b core protein gene of avian pox virus. All cases were diagnosed with avian pox virus infection. This is believed to be the first description on natural infection of avian pox in Oriental Turtle-doves in Korea.

  12. Scatter corrections for cone beam optical CT

    Energy Technology Data Exchange (ETDEWEB)

    Olding, Tim; Holmes, Oliver [Department of Physics, Queen' s University (United Kingdom); Schreiner, L John [Medical Physics Department, Cancer Centre of Southeastern Ontario (Canada)], E-mail: Tim.Olding@krcc.on.ca

    2009-05-01

    Cone beam optical computed tomography (OptCT) employing the VISTA scanner (Modus Medical, London, ON) has been shown to have significant promise for fast, three dimensional imaging of polymer gel dosimeters. One distinct challenge with this approach arises from the combination of the cone beam geometry, a diffuse light source, and the scattering polymer gel media, which all contribute scatter signal that perturbs the accuracy of the scanner. Beam stop array (BSA), beam pass array (BPA) and anti-scatter polarizer correction methodologies have been employed to remove scatter signal from OptCT data. These approaches are investigated through the use of well-characterized phantom scattering solutions and irradiated polymer gel dosimeters. BSA corrected scatter solutions show good agreement in attenuation coefficient with the optically absorbing dye solutions, with considerable reduction of scatter-induced cupping artifact at high scattering concentrations. The application of BSA scatter corrections to a polymer gel dosimeter lead to an overall improvement in the number of pixel satisfying the (3%, 3mm) gamma value criteria from 7.8% to 0.15%.

  13. Old chromophores, new photoactivation paradigms, trendy applications: flavins in blue light-sensing photoreceptors.

    Science.gov (United States)

    Losi, Aba; Gärtner, Wolfgang

    2011-01-01

    The knowledge on the mechanisms by which blue light (BL) is sensed by diverse and numerous organisms, and of the physiological responses elicited by the BL photoreceptors, has grown remarkably during the last two decades. The basis for this "blue revival" was set by the identification and molecular characterization of long sought plant BL sensors, employing flavins as chromophores, chiefly cryptochromes and phototropins. The latter photosensors are the foundation members of the so-called light, oxygen, voltage (LOV)-protein family, largely spread among archaea, bacteria, fungi and plants. The accumulation of sequenced microbial genomes during the last years has added the BLUF (Blue Light sensing Using FAD) family to the BL photoreceptors and yielded the opportunity for intense "genome mining," which has presented to us the intriguing wealth of BL sensing in prokaryotes. In this contribution we provide an update of flavin-based BL sensors of the LOV and BLUF type, from prokaryotic microorganisms, with special emphasis to their light-activation pathways and molecular signal-transduction mechanisms. Rather than being a fully comprehensive review, this research collects the most recent discoveries and aims to unveil and compare signaling pathways and mechanisms of BL sensors. PMID:21352235

  14. Low-resolution characterization of the 3D structure of the Euglena gracilis photoreceptor

    International Nuclear Information System (INIS)

    This paper deals with the first characterization of the structure of the photoreceptive organelle of the unicellular alga Euglena gracilis (Euglenophyta). This organelle has a three-dimensional organization consisting of up to 50 closely stacked membrane lamellae. Ionically induced unstacking of the photoreceptor lamellae revealed ordered arrays well suited to structural analysis by electron microscopy and image analysis, which ultimately yielded a low-resolution picture of the structure. Each lamella is formed by the photoreceptive membrane protein of the cell assembled within the membrane layer in a hexagonal lattice. The first order diffraction spots in the calculated Fourier transform reveals the presence of 6-fold symmetrized topography (better resolution about 90 A). The 2D and 3D structural data are very similar with those recently published on proteorodopsin, a membrane protein used by marine bacterio-plankton as light-driven proton pump. In our opinion these similarity indicate that a photoreceptive protein belonging to the same superfamily of proteorodopsin could form the Euglena photoreceptor

  15. FRACTURE LIMIT LOAD OF CONE SHAPE PART IN DRAWING PROCESS

    Institute of Scientific and Technical Information of China (English)

    Xu Jisheng; Gao Shiyou

    2005-01-01

    The deformation characters and load status of the blank's potential fracture zone are analyzed at the moment when blank is approaching to punch corner in drawing process of cone shape part. Based on tension instability theory, the formula for calculating fracture limit load of cone shape part in drawing process is derived. Also, the formula is analyzed and verified by experiment.

  16. Scoria Cone Construction Mechanism, Lathrop Wells Volcano, Southern Nevada

    Energy Technology Data Exchange (ETDEWEB)

    G. Valentine; D. Krier; F. Perry; G. Heiken

    2005-01-18

    Scoria cones are commonly assumed to have been constructed by the accumulation of ballistically-ejected clasts from discrete and relatively coarse-grained Strombolian bursts and subsequent avalanching such that the cone slopes are at or near the angle of repose for loose scoria. The cone at the hawaiitic Lathrop Wells volcano, southern Nevada, contains deposits that are consistent with the above processes during early cone-building phases; these early deposits are composed mainly of coarse lapilli and fluidal bombs and are partially welded, indicating relatively little cooling during flight. However, the bulk of the cone is comprised of relatively fine-grained (ash and lapilli), planar beds with no welding, even within a few tens of meters of the vent. This facies is consistent with deposition by direct fallout from sustained eruption columns of relatively well-fragmented material, primarily mantling cone slopes and with a lesser degree of avalanching than is commonly assumed. A laterally extensive fallout deposit (up to 20 km from the vent) is inferred to have formed contemporaneously with these later cone deposits. This additional mechanism for construction of scoria cones may also be important at other locations, particularly where the magmas are relatively high in volatile content and where conditions promote the formation of abundant microlites in the rising mafic magma.

  17. The dynamics of a steady Taylor cone electrospray

    Science.gov (United States)

    Bell, Martin; Rutgers, Maarten A.

    1998-11-01

    A liquid drop at the tip of a needle will become conical if a high voltage is supplied to the needle. This is known as a Zeleny^1-Taylor^2 cone. Due to the finite conductivity of most liquids, a thin liquid jet will emerge from the cone tip. This jet can be thinner than 1 micrometer and move with speeds in excess of 10 m/s! The jet breaks up due to a Rayleigh instability into a stream of monodisperse droplets. The particles themselves carry charge and can cause the droplet stream to break up into a diverging conical spray. De La Mora^3 has calculated the relation between the liquid and spray cone angles, but less in known about the dynamics with which the droplets move from the initial jet into the final electrospray cone. We have observed electrosprayed droplets in a regime where the Taylor cone oscillates axisymmetrically, leading to an interrupted spray. By periodically driving the volume of the Taylor cone, and illuminating the spray stroboscopically at the same frequency, we can essentially `freeze' the evolution of a packet of droplets in the spray cone. We clearly observe the disintegration of the initial jet of droplets into a growing spherical cloud. The expanding clouds can be inscribed in the cone of an uninterrupted electrospray. ^1J. Zeleny, Phys. Rev. 3:69, (1914), ^2G.I. Taylor, J. Fluid Mech. 2:1, (1965) ^3J.F. De La Mora, J. Fluid Mech. 243:561, (1992)

  18. Rational convex cones and cyclotomic multiple zeta values

    OpenAIRE

    TERASOMA, Tomohide

    2004-01-01

    In this paper, we introduce zeta values of rational convex cones, which is a generalization of cyclotomic multiple zeta values. These zeta values have integral expressions. The main theorem asserts that zeta values of cones can be expressed as linear combinations of cyclotomic multiple zeta values over some cyclotomic field.

  19. OPTMIZATION AND DUALITY OF CONE-D.C.PROGRAMMING

    Institute of Scientific and Technical Information of China (English)

    YINZHIWEN; LIYUANXI

    1995-01-01

    This paper gives the definitions and some properties of ε-directional derivate and ε-subgradients of cone-convex function.From them,the optimality conditions of local and global optimal point of unconstrained cone-d.c. programming are gained.At last,the duality theorems of this programming are presented.

  20. The Double Cone: A Mechanical Paradox or a Geometrical Constraint?

    Science.gov (United States)

    Gallitto, Aurelio Agliolo; Fiordilino, Emilio

    2011-01-01

    In the framework of the Italian National Plan "Lauree Scientifiche" (PLS) in collaboration with secondary schools, we have investigated the mechanical paradox of the double cone. We have calculated the geometric condition for obtaining an upward movement. Based on this result, we have built a mechanical model with a double cone made of aluminum…