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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 27 (1971), S. 63-68 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The authors have elaborated a suitable method of detection of PAS-positive substances with chemicals in common use-thiosemicarbazide-both on semi-thick sections and tissue blocks for electron microscopic purposes. The method is sufficiently sensitive even in the presence of only a small amount of PAS-positive substances. They found that the specifity of this method is the same as that in the PAS method used for light microscopy. The structure of the cells remains surprisingly well preserved, especially in comparison with other methods in current use.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular histology 15 (1983), S. 310-311 
    ISSN: 1573-6865
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 8 (1983), S. 267-277 
    ISSN: 0148-7280
    Keywords: nucleolar structure ; RNA metabolism ; oocyte ; human ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Nucleolar ultrastrure was studied in fully grown human oocytes obtained from multilaminar preantral follicles and from follicles at different stages of antrum formation. Selective staining for ribonucleoproteins and 3H-uridine labeling were used in attempt to better understand the nature and functional significance of homogeneous dense nucleoli found in oocytes from large antral follicles.There was an apparent increase in the radio of nucleonema to nucleolar interstices, accompanied by a gradual degranulation of the nucleolonema during early stages of antrum fromation. The process of nucleolar homogenization continued in oocytes from medium-size antralfollicles, island of more tightly packed fibrils being hybothesized to represent persisting active transcription units. Entirely filamentous and homogeneous nucleoli were typical for oocytes from large antral follicles. They were demonstrated to ribonucleoprotein filaments embedded in pale- staining matrix. They were demonstrated to contain newly synthesized RNA after a 30-min pulse with 3H-uridine. The described nucleolar transformations are interpreted as acorrelate of nucleolar transition from a site of RNA synthesis into a site of RNA Storage during in human oocyte preovulatory development.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0148-7280
    Keywords: egg fusion ; sperm ; capacitation ; fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In the course of in vitro fertilization of zona-free hamster and pig eggs by boar and guinea-pig spermatozoa it was observed that homologous and heterologous eggs fused together, forming cell hybrids between two or more cells. The fusogenic activity was attributed to spermatozoa and this was the hypothesis tested. The fusogenic activity (coinciding with sperm penetration activity) was dependent on the duration of sperm preincubation, which may be regarded as capacitation in vitro. Fusion occurred only after 3 hr of sperm preincubation and a narrow optimum was detected at 4-4.5 hr. Fusion of eggs was also dependent on sperm concentration. A relatively high proportion of fusions was observed at a sperm concentration of 4.0 × 104 per ml and an optimum was attained at a concentration of 5.0 × 105 per ml. The first fusions were observed at 90 min after semination. After 3 hr more than a half of the eggs reacted, and by 20 hr of incubation 80% of ova were fused. The fusability of eggs was tested and found to occur at 14 hr after ovulation. The fusion process was also studied using transmission electron microscopy. It is supposed that the process of egg fusion may be caused either by a similar mechanism to sperm-egg fusion, or by products released during the sperm acrosome reaction.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Publication Date: 1971-03-01
    Print ISSN: 0018-2222
    Electronic ISSN: 1432-119X
    Topics: Biology , Medicine
    Published by Springer
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