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  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructural aspects of the preattached pig embryo: Cleavage and early blastocyst stages (1973)
    Springer
    Anatomy and embryology 143 (1973), S. 95-114 
    Details
    ISSN: 1432-0568
    Keywords: Cleavage stages ; Blastocyst ; Pig ; Nucleus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural observations of morphological changes in nuclei and cytoplasm of pig embryos during cleavage and early blastocyst stages are presented. Compact nuclear bodies (nucleosphaeridies) are demonstrable in the cleavage stages, and occasionally in the inner cell mass of blastocysts. The transformation of nucleosphaeridies leading to the formation of a peripheral network are usually found at the eight-cell stage. In morula, nucleoli make their first appearance as clearly distinguishable morphological entities. A marked disorganization of nuclear envelope is observed near to the cytoplasmic annulate lamellae (CAL) indicating a possible process of transformation of the former to the latter. During premorula stages cytoplasmic organelles (Golgi complex, endoplasmic reticulum, and CAL) are predominantly concentrated around the nucleus. CAL associated with fibrillogranular material similar to the material of the nucleoplasm occur in juxtanuclear positions. In the two-cell stage, degenerating paternal mitochondria are observed. In the morula the number of spherical mitochondria fell while that of elongated mitochondria increase. The trophoblast cells of the blastocyst stage contain cytoplasmic microfilaments which are closely associated with cell organelles, particularly the desmonsomes. Structurally changed mitochondria near the yolk globules and inclusion bodies of various morphology are found. A basal lamina is discernible parallel to the trophoblast layer facing the blastocoel. The observations are discussed in relation to physiological phenomena known to occur during embryogenesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00519913
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  • 2
    Electronic Resource
    Electronic Resource
    Nucleosphaeridies in early pig embryos (1970)
    Springer
    Cell & tissue research 110 (1970), S. 61-71 
    Details
    ISSN: 1432-0878
    Keywords: Nucleus ; Nucleosphaeridies ; Ultrastructure ; Embryo ; Pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Spherical fibrillogranular nuclear structures, here called nucleosphaeridies, were observed in pig embryos ranging between the two-cell-stage and the early blastocyststage. Up to four nucleosphaeridies, averaging 2 to 4 μm in diameter and different from the common nucleoplasmic structures, were found in a single thin section. As a rule the nucleosphaeridies are situated at random in the nucleoplasm, sometimes in contiguity with the nuclear envelope. Occasionally, they are located within the nucleolus. There is morphological similarity between the nucleosphaeridies situated within the nucleolus and those situated in the nucleoplasm. Based on these morphological observations, considerations are given as to whether these nucleosphaeridies are synthesized by the nucleoli, or inversely, these structures are precursors in the development and maturation of the nucleoli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00343985
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructure of pig tubal ova (1973)
    Springer
    Cell & tissue research 141 (1973), S. 103-122 
    Details
    ISSN: 1432-0878
    Keywords: Tubal ova ; Pig ; Mitochondria ; Annulate lamellae ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The unfertilized ova of the pig are characterized by the first polar body situated in the perivitelline space. The metaphase chromosomes of the ova are found free in a cortical area, predominantly inhabited by the spindle fibers. Mitochondria show morphological changes in the form of swelling of their matrices. Frequently, the membranes of the individual cristae mitochondriales meet each other, forming meeting points, at regular intervals. The endoplasmic reticulum increases in quantity when compared with that of the pig follicular oocytes (Norberg, 1972b). The Golgi complexes are sparse and scattered. Occasionally, remnants of the end bulbs of the corona radiata cell processes occur below the surface membrane of the ova. Usually, the sperm-penetrated ova contain the first and the second polar body within the perivitelline space. Intranuclear annulate lamellae are observed within the male and female pronucleoplasm, and of particular interest are extended linear structures in one of the pronuclei. These structures may be considered as precursor stage in the formation of the intranuclear annulate lamellae. The parapronuclear cytoplasm is rich in organelles, especially the cytoplasmic annulate lamellae. In contrast to the scarcity of Golgi complexes in the unfertilized ova, many newly formed Golgi vesicles and lamellae reappear in the pronuclear stage. The zona pellucida displays ultrastructural changes following sperm penetration of the ova.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307399
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    The morphological relationship between mitochondria and cytoplasmic membranes of the follicular oocyte in domestic pig (1972)
    Springer
    Cell & tissue research 124 (1972), S. 520-531 
    Details
    ISSN: 1432-0878
    Keywords: Mitochondria ; Cytomembranes ; Oocyte ; Pig ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An ultrastructural study of the mature follicular oocytes in domestic pig demonstrate a morphological relationship between the mitochondria and the cytoplasmic membranes immediately surrounding the yolk globules of the cells. Frequently, the cytoplasmic membranes are observed to be in close proximity of the mitochondria or are found to be continuous with the outer mitochondrial membrane. Sometimes the cytoplasmic membranes are found to display the formation of one or more oval loops of different diameter located at their presumed ends or free in the nearby cytoplasm. The significance of these observations is discussed in the light of the available informations, which suggest that the cytomembrane system in certain phases of development may take part in the formation of mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00335255
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  • 5
    Electronic Resource
    Electronic Resource
    The follicular oocyte and its granulosa cells in domestic pig (1972)
    Springer
    Cell & tissue research 131 (1972), S. 497-517 
    Details
    ISSN: 1432-0878
    Keywords: Granulosa cells ; Oocyte ; Pig ; Mitochondria ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pig oocytes and their surrounding granulosa cells obtained from mature Graafian follicles at a stipulated time near to ovulation were studied in some details electronmicroscopically. Particular emphasis is given to the corona radiata cell processes and to the heterogeneous population of mitochondria in the oocyte. The corona radiata cell processes contain various components such as filaments, mitochondria, multivesicular bodies and lipid droplets in their matrix. The contact relationship of the corona radiata cell processes to the oocytes is maintained by desmosomes. Usually, the two parallel surface membranes forming the desmosome are separated by a space of about 200 Å. Occasionally, the two membranes approximate each other to form a junction having a “gap” of about 70 Å. Apparently the membranes become fused in some regions. Of particular interest is the distribution and structural characteristics of the single-membrane-bounded structures, and their relationship to the cytomembranes and the mitochondria. On the basis of the present and earlier (Norberg, 1972) observations, the question arises whether the formation and development of mitochondria of pig oocytes depend, at least partly, on a metamorphosis of single-membrane-bounded structures derived from less complex membraneous elements. Final conclusions concerning this problem demand integrated morphological and biochemical investigation regarding the biosynthesis of mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00306967
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    Paper (German National Licenses)
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