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  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructural changes in spermatozoa of the Brush-tailed possum, Trichosurus vulpecula (Marsupialia), during epididymal transit (1975)
    Springer
    Cell & tissue research 164 (1975), S. 121-132 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00221699
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructural changes in spermatozoa of the brush-tailed possum, Trichosurus vulpecula (Marsupialia), during epididymal transit (1976)
    Springer
    Cell & tissue research 171 (1976), S. 61-73 
    Details
    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
    URL: http://dx.doi.org/10.1007/BF00219700
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  • 3
    Electronic Resource
    Electronic Resource
    Spermiogenesis in the brush-tailed possum, Trichosurus vulpecula (Marsupialia) (1976)
    Springer
    Cell & tissue research 171 (1976), S. 75-90 
    Details
    ISSN: 1432-0878
    Keywords: Acrosome ; Trichosurus vulpecula (Marsupialia) ; Spermiogenesis ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Acrosome development in the Australian Brush-tailed possum, Trichosurus vulpecula, displays a number of extraordinary features. This is particularly evident in the later stages of spermiogenesis, when the area of the nuclear surface bounded by the nuclear ring, and covered by the acrosome, is reduced considerable. As a result, the acrosomal material becomes located over its definitive position on the anterior third of the dorsal nuclear surface; in this process it is thrown into a series of folds, and a wide subacrosomal space is formed. Further changes around the time of spermiation result in the release of a spermatozoon in which a thin layer of acrosomal material is closely applied to the nucleus over the area of the definitive location of the acrosome, whilst its margins are greatly extended and project freely away from the nucleus. The latter feature does not appear to have been reported for the sperm of other mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219701
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  • 4
    Electronic Resource
    Electronic Resource
    Crystalloid inclusions in the Sertoli cell of the koala, Phascolarctos cinereus (Marsupialia) (1982)
    Springer
    Cell & tissue research 221 (1982), S. 633-642 
    Details
    ISSN: 1432-0878
    Keywords: Sertoli cell ; Crystalloids ; Koala (Phascolarctos cinereus) ; Marsupialia ; Transmission electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Crystalloid inclusions are a common feature in the basal region of Sertoli cells in the koala, Phascolarctos cinereus. Generally located near the nucleus, they are non membrane-bounded, slender rectangular structures composed of tubules which are orientated at right angles to the long axis of the crystalloid and regularly arranged in rows parallel to this long axis. The tubules in adjacent rows are offset from one another at definite angles and extensively interconnected by filaments. Neither the composition nor function of the crystalloids has been determined, but their association with tonofilaments and the presence of ribosomes in the vicinity suggests that they are most likely proteinaceous.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215707
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