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>An electron microscopic and autoradiographic study of mesogleal organization and collagen synthesis in the sea anemoneAiptasia diaphana
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An electron microscopic and autoradiographic study of mesogleal organization and collagen synthesis in the sea anemoneAiptasia diaphana
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机译:An electron microscopic and autoradiographic study of mesogleal organization and collagen synthesis in the sea anemoneAiptasia diaphana
Electron microscopy and autoradiography (H3-proline) were used to determine the cell(s) responsible for collagen synthesis and lamination in the mesoglea of the sea anemone,Aiptasia diaphana. Mesogleal collagen is synthesized by the epidermal epitheliomuscular cells which contain much rough endoplasmic reticulum, and secretory vesicles attached to microtubules which cross the basal plasmalemma and anchor in the basement membrane; these cells incorporate large amounts of H3-proline. The mesogleal collagen fibers are non-striated, have clear centers, and a diameter of 200–260 Å; their walls are composed of 65 Å diameter subunit fibrils which appear to be helically oriented. Epitheliomuscular cells rest upon a subepidermal basement membrane which is composed of mesogleal collagen fibers, 65 Å subunit fibrils, and dense granules. This subepidermal basement membrane labels definitively with H3-proline, and is the region where soluble collagen precursors apparently form subunit fibrils which associate to yield mesogleal fibers. The columnar mesogleal collagen fibers are arranged to form layers: the fibers of each layer have the same longitudinal orientation, while those of adjacent layers display an approximate orthogonal arrangement. It is felt that the subepidermal basement membrane is responsible for this organization of mesogleal fibers. Mesogleal amoebocytes do not label with H3-proline and show no ultrastructural evidence of collagen secre
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