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  • Electronic Resource  (2)
  • 1990-1994  (2)
  • 1935-1939
  • Australian rodents  (1)
  • Sperm - egg interaction  (1)
Material
  • Electronic Resource  (2)
Years
  • 1990-1994  (2)
  • 1935-1939
Year
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 32 (1992), S. 277-292 
    ISSN: 1040-452X
    Keywords: Oocyte maturation ; Sperm - egg interaction ; Sperm incorporation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Various morphological aspects of in vivo egg maturation and sperm - egg interaction were investigated in the Australian marsupial Sminthopsis crassicaudata with the transmission and scanning electron microscopes. Cortical granules invariably occurred in primary oocytes, with the number increasing after resumption of the first meiotic division. They generally occurred close to the oolemma, including the region near the oocyte nucleus. After mating, spermatozoa with intact acrosomes, which had a homogeneous electron-dense matrix, were found on the outer zona surface, but loss of acrosomal contents had occurred by the time of zona penetration. Sperm incorporation into the egg took place at the metaphase II stage of meiosis, and, at this time, cortical granules disappeared from the egg cortex. Sperm heads with condensed chromatin in the egg cytoplasm had an electron-dense layer of subacrosomal material over part of the dorsal nuclear surface, but no membranes were present around these incorporated spermatozoa. Sperm chromatin decondensation resulted in an elevation of egg cytoplasm, and the cell membrane over this area lacked microvilli. The pronuclear envelope was not laid down until after chromatin decondensation had occurred. By this time the fertilized egg had reached the uterus, and a smooth, electron-dense, shell membrane had been deposited. These observations, together with our previous findings, indicate that some of the processes of sperm - egg interaction are similar to those in eutherian mammals, whereas others appear highly divergent.
    Additional Material: 47 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 30 (1991), S. 369-384 
    ISSN: 1040-452X
    Keywords: F-actin ; Sperm head ; Australian rodents ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The distribution of filamentous actin around the maturing sperm head and in spermatozoa of four species of Australian conilurine rodents was investigated at the light and electron microscopic levels. Similar results were obtained for all the species studied. Mechanically isolated spermatids had NBD-phallacidin-positive longitudinal bands of fluorescence over the dorsolateral surface and, in late spermatids, bands of bright fluorescence passed perpendicularly from the dorsal convex to ventral concave surface. TEM observations indicated that these regions corresponded to filaments of ectoplasmic specializations and granular filamentous material around the tubulobulbar complexes, respectively. In testicular and cauda spermatozoa NBD-phallacidin fluorescent material was present in the two ventral processes that extended from the upper concave surface of the sperm head; also fainter material occurred along the concave border and as a dorsocaudal spur. Its distribution was identical for testicular and cauda spermatozoa. TEM of late spermatids showed that in the ventral process closest to the apical hook there were between 170 and 245 filaments, which attached to the inner surface of the postacrosomal dense lamina; in the more caudal ventral process about 70 filaments occurred. No filaments were, however, visible in the mature spermatozoon but, after immunocytochemical labelling for actin, deposition of gold particles was evident over ventral processes of both late spermatids and cauda spermatozoa. Within the female tract these ventral processes made contact with the zona matrix and were taken into the egg cytoplasm unchanged in morphology. The possible functional significance of the filamentous actin in these structures is discussed.
    Additional Material: 39 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
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