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  • 1965-1969  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Acrosome morphogenesis in Lumbricus terrestris (1968)
    Springer
    Cell & tissue research 85 (1968), S. 398-407 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Acrosome morphogenesis commences in the juxtanuclear cytoplasm at the posterior end of spermatids of Lumbricus terrestris. A dense rod-shaped structure and the Golgi apparatus together participate first in forming an acrosome vesicle that contains the acrosome granule, and somewhat later shape the conical base of the acrosome in the cytoplasm beneath the vesicle. Cytoplasmic flow may account for the migration of the immature acrosome to the apical surface of the nucleus of the spermatid. Manchette microtubules play a key role in the final modelling of the acrosome. Sheathed by the manchette the acrosome elongates to 3–4 times its pre-attachment length. The conical base of the acrosome then extends anteriorly to enclose the acrosome vesicle. A dense rod emerging from the rod-shaped granule occupies an indentation of the base of the acrosome vesicle. The mature acrosome of Lumbricus is an extremely complex structure about 5–7 microns long and is bounded by the plasmalemma of the spermatozoon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328849
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Cytodifferentiation of the crayfish spermatozoon: acrosome formation, transformation of mitochondria and development of microtubules (1967)
    Springer
    Cell & tissue research 77 (1967), S. 80-94 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During spermiogenesis in the crayfish, the acrosome, mitochondrial derivatives and the centrioles are retained within the admixed nucleoplasm and cytoplasm (spermioplasm). Fused nuclear and plasma membranes form the tegument that invests the spermioplasm. A well-defined system of small tubules that originate during spermiogenesis from densities surrounding the centrioles also defines the axes of the nuclear processes in the mature spermatozoon. These tubules are larger in diameter than the microtubules in adjacent interstitial cells and their development coincides with the formation and extension of the nuclear processes. The small tubules seem related to the changes in the cell accompanying nucleoplasmic streaming and to the growth and stabilization of form of the elongate, assymmetric nuclear processes. The mitochondria of spermatocytes are transformed into membranous lamellae that lie in the spermioplasm of the mature spermatozoon, and may by oxidative phosphorylation or some alternative pathway provide energy for metabolic activity and motility. The apical cap of the mature acrosome of the crayfish spermatozoon is enveloped by a sheath of PAS-positive material. The acrosomal process is attached to a dense crescent-shaped acrosome embedded in the spermioplasm. A fine granular substance at the base of the acrosome gives rise to beaded filaments that radiate into the central acrosomal concavity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336700
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A comparative study of microtubules in some vertebrate and invertebrate cells (1966)
    Springer
    Cell & tissue research 71 (1966), S. 1-13 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An electron microscope study of a variety of invertebrate and vertebrate cell types has supported the postulate that the microtubule is a universal cellular organelle. Microtubules of similar dimensions have been observed in the flagellum and beneath the plasma membrane of Trypanosoma lewisi, in the flagellum, manchette and mitotic spindle of the earthworm (Lumbricus terrestris) spermatid; and in fibroblasts, proximal convoluted and collecting tubule cells of the hypertrophying rat kidney. The specific occurrence and organization of the microtubules in cells undergoing morphological and developmental changes have suggested that these organelles are contractile and that they effectively contribute to the maintenance of cellular form. The possibility that microtubules may function as an intracellular transport system is also suggested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00339826
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    A comparative electron microscope study of visceral muscle fibers in Cambarus, Drosophila and Lumbricus (1967)
    Springer
    Cell & tissue research 79 (1967), S. 581-591 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The arrangement of myofilaments in the striated visceral muscle fibers of two arthropods (crayfish and fruitfly) and in the unstriated visceral fibers of one annelid (earthworm) was studied comparatively. Transverse sections through the A bands of arthropod visceral fibers indicate that each thick myofilament is surrounded by approximately 12 thin filaments. The myofilaments are less organized in the visceral fibers of the earthworm than in muscle fibers of the crayfish and fruitfly. The thick myofilaments of the earthworm are composed of subunits, 20–30 Å in diameter. The presence of two distinct sets of myofilaments in these slowly contracting striated and unstriated visceral muscle fibers suggests that contraction is accomplished via a sliding filament mechanism. In crayfish visceral fibers the sarcolemma invaginates at irregular intervals to form a long and unbranched tubular system at any level in the sarcomere. Dyads formed by the apposition of T and SR membranes are observed frequently. The distribution of the T and SR systems in the visceral fibers of the fruitfly and the earthworm is markedly reduced and dyads are infrequently observed. The reduced T and SR systems may be related to the slow contraction of these fibers. Transport of specific substances across the sarcolemma could initiate contraction or relaxation in these fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336314
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Histochemical and electron microscopic observations on the salt secreting lacrymal glands of marine turtles (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 118 (1966), S. 337-357 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The lobular, compound, branched, tubular, salt-secreting lacrymal glands of two marine turtles, Chelonia mydas and Caretta caretta are similar in structure and in histochemical reactivity. Blood from the centrolobular arteries flows through a rich capillary bed counter to the flow of tubule secretion. The capillary endothelium is reactive for adenosine triphosphatase (ATPase). Nerves containing cholinesterase pervade the connective tissue. At the blind ends of the secretory tubules small basophilic peripheral cells contain an abundance of glycogen, monoamine oxidase (MAO) and phosphorylase but little succinic dehydrogenase (SDH) or cytochrome oxidase (CTO). Non-mitochondrial ATPase is concentrated at the luminal interface of these cells. The larger principal cells, lining the major portion of the secretory tubules, are rich in SDH and CTO but contain relatively little glycogen, MAO or phosphorylase. Broad intercellular channels reactive for mucopolysaccharide are formed by intermeshing, pleomorphic microvilli that fringe the extensive lateral surfaces of the principal cells. The cytoplasm of these cells contains profiles of smoothsurfaced endoplasmic reticulum (SSER), abundant mitochondria, and prominent Golgi membranes. Profiles of SSER and small membrane bound vesicles fill the apical cytoplasm but mitochondria are lacking. The luminal secretory border of the cell is extremely limited in area.Two types of epithelial cells line the duct system: basal cells that react strongly for non-specific esterase and MAO; and goblet cells containing mucopolysaccharide, acid phosphatase, cholinesterase, and ATPase.The principal cells, close to the arterial blood supply, contain the highest concentrations of oxidative enzymes and have special modifications of the cell surface consistent with their role in salt concentration and secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001180203
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    Paper (German National Licenses)
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