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  • 1
    Electronic Resource
    Electronic Resource
    Fertilization of investment-free Xenopus eggs
    Amsterdam : Elsevier
    Experimental Cell Research 154 (1984), S. 639-642 
    Details
    ISSN: 0014-4827
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0014-4827(84)90191-5
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  • 2
    Electronic Resource
    Electronic Resource
    Loss of functional sperm entry into Xenopus eggs after activation correlates with a reduction in surface adhesivity
    Amsterdam : Elsevier
    Developmental Biology 120 (1987), S. 434-446 
    Details
    ISSN: 0012-1606
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0012-1606(87)90247-8
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  • 3
    Electronic Resource
    Electronic Resource
    The Timing of Cortical Granule Fusion, Content Dispersal, and Endocytosis during Fertilization of the Hamster Egg: An Electrophysiological and Histochemical Study
    Amsterdam : Elsevier
    Developmental Biology 162 (1994), S. 277-287 
    Details
    ISSN: 0012-1606
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1006/dbio.1994.1085
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  • 4
    Electronic Resource
    Electronic Resource
    A cell surface block to polyspermy occurs in golden hamster eggs
    Amsterdam : Elsevier
    Developmental Biology 128 (1988), S. 150-157 
    Details
    ISSN: 0012-1606
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0012-1606(88)90277-1
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  • 5
    Electronic Resource
    Electronic Resource
    The temporal and spatial relationships between cortical contraction, sperm trail formation, and pronuclear migration in fertilizedXenopus eggs (1982)
    Springer
    Development genes and evolution 191 (1982), S. 241-245 
    Details
    ISSN: 1432-041X
    Keywords: Cortical contraction ; Pronuclear migration ; Sperm trail ; Xenopus ; Amphibians
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The cortical contraction begins 4 min after insemination and one minute after prick activation. During the next 4 min, the pigment margin moves 15 degrees toward the animal pole. The cortex then relaxes to the prefertilization level over the next 10 min. Contrary to earlier estimations, the cortical contraction occurs during the same time span as the wave of cortical granule exocytosis. We suggest that the two events may result from a common stimulus. The sperm trail (ST) forms during the relaxation of the cortex. The ST first appears as a conically-shaped trail of pigment in the cytoplasm; it then elongates into a funnel-shaped trail as the male pronucleus migrates into the egg. The base of the cytoplasmic ST can be seen on the surface of the egg as a circular condensation of pigment. The male and female pronuclei migrate at a constant rate of 12 μm per minute. The male pronucleus migrates by the enlargement of its aster, whereas, it appears that the female pronucleus is dependent on the male aster for its motion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848411
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  • 6
    Electronic Resource
    Electronic Resource
    Time course and pattern of cortical granule breakdown in hamster eggs after sperm fusion (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 30 (1991), S. 390-395 
    Details
    ISSN: 1040-452X
    Keywords: Polyspermy blocks ; Timing ; Cortical reaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have determined the temporal relationship between sperm fusion and cortical granule breakdown in the hamster egg. Sperm fusion was determined by the Hoechst-transfer method (Stewart-Savage and Bavister: Dev Biol 128:150-157, 1988), and cortical granules were visualized with fluorescein isothiocynate-conjugated Lens culinaris agglutinin (Cherr et al. J Exp Zool 246:81-93, 1988). By 55 min after insemination, there was an 85% reduction in the density of cortical granules (fewer than four granules/100 m̈m2). Taking this value as the completion of the cortical reaction, analysis of the data indicate that the cortical reaction was completed 9 min after sperm fusion and 3 min after the formation of the zona and cell surface blocks to polyspermy. There was no obvious spatial pattern of granule loss in eggs that had a Hoechst-positive sperm but had not completed the cortical reaction.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080300414
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  • 7
    Electronic Resource
    Electronic Resource
    Sperm penetration through the zona pellucida of salt-stored hamster eggs is delayed (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 36 (1993), S. 328-330 
    Details
    ISSN: 1040-452X
    Keywords: Sperm capacitation ; Acrosome reaction ; Kinetics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: One of the problems in assaying sperm capacitation is that live eggs mount a block to polyspermy at the zona pellucida. To circumvent this problem, researchers have started to use salt-stored eggs to assay sperm capacitation (Boatman et al., Gamete Res 19:19-29, 1988; Yoshimatsu et al., Gamete Res 21:115-126, 1988). These researchers have demonstrated that the zonae of salt-stored eggs were penetrable by capacitated sperm, but they did not examine whether the timing of penetration of fully capacitated sperm was altered. This report shows that zona penetration by fully capacitated sperm is delayed in both short-term salt-treated eggs (2 hr) and in eggs stored in salt for 〉2 days. These results indicate that the zona is modified when eggs are treated with a high-salt solution. © 1993 Wiley-Liss, Inc.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080360307
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  • 8
    Electronic Resource
    Electronic Resource
    Failure of hamster eggs fertilized in vitro to extrude the second polar body correlates with high levels of polyspermy (1987)
    New York, NY : Wiley-Blackwell
    Gamete Research 18 (1987), S. 333-338 
    Details
    ISSN: 0148-7280
    Keywords: abnormal meiosis ; polyspermy ; hamster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The occurrence of second polar body (PB2) retention in in-vitro fertilized hamster eggs is reported. Of 2,872 eggs examined, 6.9% (199 eggs) failed to extrude PB2. Eggs that failed to extrude PB2 were more likely to be polyspermic than eggs with PB2 (63% and 14.6%, respectively), and the number of fusing sperm per egg was higher in the abnormal eggs. These data indicate that eggs which fail to extrude PB2 have an impaired block to polyspermy. The level of PB2 retention varied between females and ranged from all eggs extruding PB2 to 20% of the eggs failing to extrude PB2 (41% and 4% of the females, respectively). There was no correlation within a female between the percentage of eggs that failed to extrude PB2 and the level of polyspermy in the sister eggs with PB2. Therefore, regardless of the condition of their sister eggs, eggs that fail to extrude PB2 have an impaired block to polyspermy and eggs that extrude PB2 have a normal block.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120180407
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  • 9
    Electronic Resource
    Electronic Resource
    Success of fertilization in golden hamsters is a function of the relative gamete ratio (1988)
    New York, NY : Wiley-Blackwell
    Gamete Research 21 (1988), S. 1-10 
    Details
    ISSN: 0148-7280
    Keywords: in vitro fertilization ; gamete ratios ; hamster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Gamete concentrations can be expressed as either absolute gamete ratios (sperm/egg), the concentration of the motile sperm (sperm/ml), or as a relative gamete ratio (sperm/egg × ml). We demonstrate that the success of hamster fertilization in vitro is a function of the relative gamete ratio and that any effect of the insemination medium geometry is minimal. Consistent fertilization occurs when the relative gamete ratio is above 103.5 sperm/egg × ml, but becomes variable above 105.0 sperm/egg × ml. At suboptimal relative gamete ratios, there is a strong sperm concentration effect on both the consistency and level of fertilization, whereas the absolute gamete ratio only affects the overall level of fertilization. These effects are seen when the sperm concentration is below 103.5 sperm/ml and when the absolute gamete ratio is below 102.3 sperm/egg. These influences are probably due to reduced sperm survival at low sperm concentrations and due to a sampling error that occurs when small numbers of sperm are transferred. When the absolute gamete ratios found in vivo in the hamster [Cummins and Yanagimachi, 1982, Gamete Res 5, 239-256] are converted to relative gamete ratios, they are similar to our in vitro results. Thus relative gamete ratios allow, for the first time, comparison between in vitro and in vivo data in the hamster, and between other rodents.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120210102
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  • 10
    Electronic Resource
    Electronic Resource
    Polarity of the surface and cortex of the amphibian egg from fertilization to first cleavage (1991)
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 17 (1991), S. 369-383 
    Details
    ISSN: 0741-0581
    Keywords: Anuran ; Animal-vegetal axis ; Functional sperm entry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The anuran egg is polarized along its animal-vegetal axis and becomes bilaterally symmetrical before first cleavage. Functional sperm entry is regionally restricted to the animal hemisphere of the egg, and functional sperm entry does not occur after egg activation. This regional and functional restriction in sperm entry correlates with the presence of long, slender microvilli and with the presence of the filamentous component of the glycocalyx. After sperm fusion, the egg undergoes activation, including a depolarization of the membrane potential and exocytosis of granules in the cortex. Both of these activation responses are the result of a propagated increase in intracellular calcium. The egg's ability to undergo a propagated activation response develops after germinal vesicle breakdown and depends on the development of the cortical endoplasmic reticulum. Once activated, the radial symmetric egg acquires bilateral symmetry due to a rotation of the egg cortex relative to the inner cytoplasm. A transient array of parallel microtubules forms near the vegetal cortex and may be part of the motor driving the cortical rotation.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1060170402
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