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  • 1
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 155 (1978), S. 271-285 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The micro-anatomy of the corpuscles of Stannius of the toadfish, Opsanus tau, an aglomerular marine teleost, has been studied by light and electron microscopy. The corpuscles are composed of extensively anastomosed cords of epithelial cells which maintain intimate contact with blood capillaries. Most of the epithelial cells contain acidophilic granules which also show a positive reaction with the periodic acid-Schiff technique and aldehyde fuchsin. On the basis of fine structural criteria, three cell types can be recognized. The granular cells contain abundant quantities of granular endoplasmic reticulum, ribosomes, Golgi apparatus with prosecretory granules, coated vesicles, polymorphic mitochondria with lamellar cristae, filaments, microtubules, a cilium, a variety of lysosome-like dense bodies, glycogen particles, lipid droplets, secretory granules and intranuclear lipid-like inclusions. One variety of agranular cell (type I) is characterized by the total absence of secretory granules, but it contains large amounts of granular endoplasmic reticulum and ribosomes, conspicuous profiles of Golgi apparatus, coated vesicles and sometimes an abundance of glycogen. Another variety of agranular cell (type II) has poorly developed cytoplasmic organelles. The perivascular space between the capillary and parenchyma contains connective tissue cells and abundant nerve fibers. The different types of epithelial cells observed in the corpuscles of Stannius of this fish may represent functional stages of the secretory cycle in a single cell type.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The ultrastructure of the adrenocortical homologue (AH) of the north American eel (Anguilla rostrata) was studied from freshwater and long-term (1.5 years) seawater (SW) adpated animals. The AH tissue situated in the wall of cardinal veins is surrounded by a thin layer of collagenous capsule; in the region away from the vein wall, parenchymal cells are separated by interstitial lacunae containing collagen bundles, capillaries, chromaffin cells and nerve fibers often applied closely to the surface of AH cells. The free surface of the cell near the vein wall, capillaries or interstitial space extends numerous slender microplicae. The cytoplasm is characterized by the presence of mitochondria with tubular cristae, a network of smooth endoplasmic reticulum, a few cisternae of rough surfaced endoplasmic reticulum, well developed Golgi apparatus, coated vesicles, centrioles, cilium, filaments, microtubules, dense bodies of variable nature and a scarcity of liposomes. The cell nuclei possess invaginated cytoplasmic pseudo-inclusions. Electron histochemical reaction for free cholesterol revealed the occurrence of needle-shaped crystals mainly associated with surface microplicae and smooth endoplasmic reticulum, which seems to be the major organelle for storage or synthesis of this steroid precursor. SW animals indicated ultrastructural signs of stimulated steroid synthesis and secretion, i.e., high degree of pseudo-follicle formation, increased electron density of mitochondria, greater abundance of lysosomal dense bodies, hyperactivity of Golgi apparatus and dilation of smooth endoplasmic reticulum tubules. Some SW fishes showed extensive deposition of osmiophilic inclusions in the mitochondria and stacks of elongated cup-shaped mitochondria. Chronic seawater acclimation enhances AH activity as judged by ultrastructural criteria with ultimate mitochondrial degeneration resulting possibly from prolonged cortisol hypersecretion; the latter may be linked with physiologic re-adjustment of ionic transfer mechanism in hyperosmotic medium.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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