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  • 1
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 297-303 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Whenever individuals of the freshwater sponge Ephydatia fluviatilis belonging to different strains come into contact, they reject each other by building a nonmerging front. The present work describes the development, the structure, and the nature of the barrier secreted between two individuals. The observations reported give unequivocal data about the collagen nature of the incompatibility barrier. First, ultrastructural investigations reveal the presence of fibrils and microfibrils which are, respectively, typical of collagen and spongin. Second, incorporation of tritiated proline, a characteristic precursor of collagen and related products, is particularly intense in the front. The involvement of several cell types in the barrier formation is discussed. The allogeneic incompatibility reaction between E. fluviatilis individuals appears very close to the process of allograft chronic rejection that we formerly described for some marine sponges. Both phenomena are basically analogous to the process which fixes to and isolates the sponges from their substrate.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 183 (1985), S. 137-144 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The present study investigates the morphological aspects of nonself recognition between three incrusting sponge species living in contact.Two types of association have been observed: nonmerging fronts and epizoism. In two of the three combinations studied, Hymeniacidon sanguinea/Halichondria panicea and Halichondria panicea/Ophlitaspongia seriata, nonself contacts consisted of either epizoism or of nonmerging fronts. In contrast, only nonmerging fronts were observed between Hymeniacidon sanguinea and Ophlitaspongia seriata.In the two types of associations, the main phenomenon consists of the isolation of the foreign sponges by a spongin barrier secreted by the partners in the zone of contact. The microscpic structure and the thickness of the barrier vary according to the type of association and the species paired, but they are clearly defined for a given combination.The conditions required for the establishment of epizoism and the existence of a natural xenogeneic tolerance between sponges are discussed.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 190 (1986), S. 307-318 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Exocytosis of residual bodies by choanocytes, archeocytes and endopinacocytes lining the aquiferous system of Ephydatia fluviatilis has been demonstrated using calibrated latex beads and Escherichia coli as tracers. In passing into the mesohyl or the lumen of the exhalant aquiferous canals, beads, and altered bacteria were enveloped by the plasma membrane of the cell containing them. The membrane constricted at a neck region to form extruding vacuoles. This process appeared first in choanocytes and later in other cell types. The occurrence of these buds increased with the length of incubation time, as did the number of particles they contained. Acid phosphatase activity was frequently associated with the particles budding from the cell membrane, confirming that this process followed digestive activity.Membranous vacuoles were recovered from the external medium and observed by TEM and those adhering to the substratum were seen by SEM. These observations proved that vacuoles were released from the sponges. This membrane-consuming mechanism of exoctyosis implies intense membrane replacement in the digestive cells of the sponge.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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