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  • 1
    ISSN: 1432-0878
    Keywords: Sperm flagellum ; Trichosurus vulpecula (Marsupial) ; Epididymal maturation ; Transmission and Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During epididymal transit, a fibre network and an array of vesicles develop in the posterior two-thirds of the midpiece in sperm of the Brush-tailed possum, Trichosurus vulpecula. The fibre network is developed by the time the sperm reach the corpus epididymidis, and is composed of evenly spaced, helically arranged fibres lying immediately beneath the plasma membrane. The angle of these fibrous helices is always counter to that of the underlying mitochondrial helix. Separating the fibre network from the mitochondria is a layer of granular material which develops at the same time, and over the same length of the midpiece as the fibre network. A somewhat tenuous fibre network is found between the fibrous sheath and plasma membrane in the anterior principal piece of sperm from all regions of the epididymis. The array of vesicles is developed by the time sperm reach the cauda epididymidis. The vesicles resemble pinocytotic vesicles; some appear as invaginations of the plasma membrane, and are open to the medium surrounding the spermatozoon by a narrow neck, while others are entirely enclosed within the spermatozoon, and lie at varying distances between the plasma membrane and the layer of granular material.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0878
    Keywords: Spermatozoon ; Acrosome ; Trichosurus vulpecula (Marsupialia) ; Epididymal maturation ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The acrosome in spermatozoa from the caput epididymidis of the Australian Brush-tailed possum, Trichosurus vulpecula, typically forms a cup-like structure, sitting on the anterior third of the dorsal surface of the nucleus. The base of the acrosomal ‘cup’ is narrowly separated from the nuclear surface, while the body of the ‘cup’ projects voluminously away from the nucleus. During epididymal transit these pronounced marginal extensions of the acrosome are retracted towards the nucleus, and the electron dense acrosomal material undergoes a process of compaction within the plasma membrane of the head to produce the convex ovate form of the definitive acrosome. During this process a variety of bizarre forms of the acrosome are produced before its final configuration is attained.
    Type of Medium: Electronic Resource
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