6 research outputs found

    Intermediate filaments of zebrafish retinal and optic nerve astrocytes and Müller glia: differential distribution of cytokeratin and GFAP

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    <p>Abstract</p> <p>Background</p> <p>Optic nerve regeneration (ONR) following injury is a model for central nervous system regeneration. In zebrafish, ONR is rapid - neurites cross the lesion and enter the optic tectum within 7 days; in mammals regeneration does not take place unless astrocytic reactivity is suppressed. Glial fibrillary acidic protein (GFAP) is used as a marker for retinal and optic nerve astrocytes in both fish and mammals, even though it has long been known that astrocytes of optic nerves in many fish, including zebrafish, express cytokeratins and not GFAP. We used immunofluorescence to localize GFAP and cytokeratin in wild-type zebrafish and transgenic zebrafish expressing green fluorescent protein (GFP) under control of a GFAP promoter to determine the pattern of expression of intermediate filaments in retina and optic nerve.</p> <p>Findings</p> <p>GFAP labeling and GFAP gene expression as indicated by GFP fluorescence was found only in the Müller glial cells of the retina. Within Müller cells, GFP fluorescence filled the entire cell while GFAP labelling was more restricted in distribution. No GFAP expression was observed in optic nerves. Cytokeratin labeling of astrocytes was observed throughout the optic nerve and less intensely in cells in the retinal inner plexiform layer. The retinal inner limiting membrane was strongly labeled by anti-cytokeratin.</p> <p>Conclusions</p> <p>Studies of astrocyte function during ONR in zebrafish cannot solely rely on GFAP as an astrocyte marker or indicator of reactivity. Future studies of ONR in zebrafish should include evaluation of changes in cytokeratin expression and localization in the optic nerve.</p

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit
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