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  • Life and Medical Sciences  (3,048)
  • 1975-1979  (1,859)
  • 1970-1974  (1,189)
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Penetration of the zona-free mouse egg by capacitated epididymal sperm: Cinemicrographic observations (1978)
    New York, NY : Wiley-Blackwell
    Gamete Research 1 (1978), S. 39-46 
    Details
    ISSN: 0148-7280
    Keywords: cinemicrography ; zona-free eggs ; egg penetration ; mouse eggs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Conditions were established for routine cinemicrographic examination of sperm incorporation by living zona-free mouse eggs employing oil immersion objectives and Nomarski optics. Initial sperm attachment to the egg plasma membrane, which was reversible and appeared to require flagellar activity, involved localized areas of the head corresponding approximately to the position of the equatorial segment. Penetrating sperm lay flat on the egg and, during incorporation, appeared to sink into the egg cytoplasm, accompanied by short bursts of flagellar activity and subsequent rotation of the flagellum around its insertion point. Ensuing sperm head decondensation involved dissociation of individual particulate structures and a dramatic localized clearing in the egg cytoplasm. The normalcy of the penetration process and the potential applicability of this approach was attested to by the observations that polar body extrusion, male and female pronuclear formation, and migration through the egg cytoplasm in preparation for syngamy occurred in several sequences followed for extended time periods.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120010107
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  • 2
    Electronic Resource
    Electronic Resource
    Acceleration of onset of oocyte maturation in vitro by luteinizing hormone (1978)
    New York, NY : Wiley-Blackwell
    Gamete Research 1 (1978), S. 59-63 
    Details
    ISSN: 0148-7280
    Keywords: oocyte maturation ; LH ; ovum culture ; germinal vesicle breakdown ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The purpose of this study was to analyze the effect of luteinizing hormone (LH) on the earliest stage of oocyte maturation - the stage of breakdown of the dictyate nucleus. Oocytes were isolated from the preovulatory follicles of adult, cyclic rats. They were incubated in culture medium with or without 10 μg/ml LH. The cultures were observed continuously for up to 3 hours. Analysis of the rate of disappearance of the germinal vesicle nucleolus revealed that LH accelerated the breakdown process. The median times of disappearance were 91.3 minutes without LH and 62.3 minutes with LH. This is in accord with earlier reports on enhancement of fertilizability of oocytes matured in vitro with LH. Thus, although oocytes mature spontaneously in culture, the maturation remains LH sensitive.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120010109
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  • 3
    Electronic Resource
    Electronic Resource
    Cellular associations in the rat oocyte-cumulus cell complex: Morphology and ovulatory changes (1978)
    New York, NY : Wiley-Blackwell
    Gamete Research 1 (1978), S. 47-57 
    Details
    ISSN: 0148-7280
    Keywords: oocyte ; cumulus oophorus ; corona radiata ; zona pellucida ; hyaluronidase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Cumulus-oocyte complexes were isolated from the follicles of proestrous rats or from the oviducal ampullae of estrous rats. The zona pellucida of some complexes was dissolved before fixation. The follicular cumulus cells were seen to be held together mainly by long processes, which often extended over a distance of several cells. Large numbers of straight processes from the corona radiata cells, passing to the oocyte, surface, were seen in the space formerly occupied by the zona pellucida. Oocyte microvilli were uniformly short; none traversed the zona.The postovulatory complexes were covered by amorphous extracellular material which also filled the spaces between the cells. By lysis of this material with hyaluronidase the cumulus cells were detached. The surfaces of these cells were covered with blebs.By testing the ability of hyaluronidase to remove the corona cells from the zona pellucida of complexes isolated around the time of ovulation, it was found that the completion of retraction of the corona cells processes occurred in the oviduct, immediately after ovulation. It is suggested that the oviducal environment may influence the final step of the withdrawal of the corona cells' projections from the zona pellucida.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120010108
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  • 4
    Electronic Resource
    Electronic Resource
    Adenosine 3′,5′-cyclic monophosphate-binding protein in sea urchin eggs and embryos (1978)
    New York, NY : Wiley-Blackwell
    Gamete Research 1 (1978), S. 137-143 
    Details
    ISSN: 0148-7280
    Keywords: cAMP-binding protein ; sea urchin eggs ; development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Adenosine 3′,5′-cyclic monophosphate (cAMP) binds to high-molecular substances which are probably proteins, in homogenates of sea urchin eggs and embryos. The bound cAMP is exchangeable. Optimal pH for the binding capacity of the proteins with cAMP is 4.0, and is shifted to 5.0 in the presence of 5 mM caffeine. The level of bound cAMP increases steeply during 10 minutes of incubation. This is then followed by a less steep increase. The level of bound cAMP decreases in the presence of NaCl. The dissociation onstant between cAMP and the proteins in homogenates of unfertilized and ertilized eggs is about 10 nM, and the value in the embryos at the gastrula stage is lower than that in the unfertilized egg homogenate.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120010207
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  • 5
    Electronic Resource
    Electronic Resource
    Heat labile activating substance for ornithine decarboxylase activity in sea urchin eggs (1978)
    New York, NY : Wiley-Blackwell
    Gamete Research 1 (1978), S. 129-136 
    Details
    ISSN: 0148-7280
    Keywords: sea urchin ; ornithine decarboxylase ; polyamine ; Ca2+ ; fertilization-induced activation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In sea urchin eggs, the activity of ornithine decarboxylase (ODC) [ E C 4.1.1.17] is detectable only in the particulate fraction yielded by centrifuging egg homogenates at 10,000g for 30 minutes. ODC activity in the particulate fraction isolated from fertilized eggs is higher than that from unferti-lized eggs. ODC activity in the particulate fraction isolated from either unfertilized or fertilized eggs is enhanced by adding the supernatant fraction obtained by centrifugation at 105,000g for two hours. Heating this supernatant at 70°C for 15 minutes results In complete loss of the stimulating capacity for ODC activity. Sea urchin eggs seem to contain heat labile activating substance(s) for ODC activity. The substance does not pass through the ultrafiltration membrane Diafro UM-10. Only eggs and unhatched embryos, in which mitosis occurs frequently, contain the activating substance. In the presence of the activating substance, Ca2+enhanced ODC activity.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120010206
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  • 6
    Electronic Resource
    Electronic Resource
    Surface topography of mouse eggs before and after insemination (1978)
    New York, NY : Wiley-Blackwell
    Gamete Research 1 (1978), S. 145-155 
    Details
    ISSN: 0148-7280
    Keywords: mouse eggs ; cell surface ; in vitro fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The surface configuration of zona-free mouse ovarian eggs before and after germinal vesicle breakdown (GVBD) and of tubal eggs before and after insemination was studied by scanning electron microscopy. The surface of germinal vesicle-intact eggs was characterized by uniformly distributed, dense (2-3μm2 and slender (0.1 × 0.8μm) microvilli. Following GVBD, the mouse oolemma underwent dramatic changes which persisted essentially unmodified in uninseminated tubal eggs. These changes consisted of an apparent conversion of the oolemma from a microvillar to a smooth or ruffled configuration with approximately two ruffle-like micro-projections (0.6 × 0.4 μm) perμm2 of surface. In most eggs, both ruffled and smooth configurations ere present, creating dramatic polarities in surface topography similar to those documented previously by TEM [Nicosia et al, 1977]. Following insemination and presumed sperm-egg fusion, microvilli reappeared either from smooth areas or from the upper edge of ruffled microprojections. Zona removal appeared to induce limited reduction in the size of microvilli in some eggs. The present results emphasize the labile and dynamic nature of the egg surface and suggest a close relationship among nuclear, cytoplasmic, and surface events during the final stages of egg maturation and during fertilization.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120010208
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  • 7
    Electronic Resource
    Electronic Resource
    Mammalian sperm capacitation and fertilization in vitro: A critique of methodology (1978)
    New York, NY : Wiley-Blackwell
    Gamete Research 1 (1978), S. 165-223 
    Details
    ISSN: 0148-7280
    Keywords: capacitation ; fertilization ; spermatozoa ; methodology in vitro ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120010210
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  • 8
    Electronic Resource
    Electronic Resource
    Cell surface changes in the proteins of rabbit spermatozoa during epididymal passage (1979)
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 153-162 
    Details
    ISSN: 0148-7280
    Keywords: spermatozoa ; cell surface ; epididymis ; surface labeling ; gel electrophoresis ; proteins ; membrane ; spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Differences in the exposure of spermatozoa surface components during epididymal passage have been examined using lactoperoxidase-catalyzed 125I-iodination or labeling with 125I-diazodiiodosulfanilic acid. Labeled surface proteins obtained from caput and cauda epididymides were solubilized in detergent, separated by sodium dodecylsulfate polyacrylamide slab gel electrophoresis, and identified by radiography. Densitometer scans of autoradiograms revealed increased amounts or exposures of surface proteins of ∼35,000, ∼39,000, ∼50,000, and ∼78,000 molecular weight on the cauda epididymal spermatozoa.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120020207
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  • 9
    Electronic Resource
    Electronic Resource
    Multiple molecular forms of acid nitrophenyl phosphatase in sea urchin eggs and embryos (1979)
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 177-185 
    Details
    ISSN: 0148-7280
    Keywords: multiple enzyme forms ; acid nitrophenyl phosphatase ; sea urchin ; development ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Acid nitrophenyl phosphatases from sea urchin eggs and embryos were investigated by gel filtration. Four different forms were found in Hemicentrotus pulcherrimus, and three forms in Anthocidaris crassispina and Pseudocentrotus depressus.The first and second forms (designated AcP-1 and AcP-2) had the highest activity in the range of pH 5.6-6.0. The third (designated AcP-3) had an apparent optimum pH between pH 4.3 and 4.8, and the fourth (designated AcP-4) showed the maximum activity at pH 3.0. AcP-1 was much more thermolabile than AcP-2 and AcP-3 at 56°C. NaF inhibited AcP-2, AcP-3, and AcP-4 but not AcP-1. AcP-1, AcP-2, and AcP-3 were observed in the three species, whereas AcP-4 was not detected in A. crassispina and P. depressus. AcP-1, AcP-2, and AcP-3 were separted by gel filtration.AcP-1 and AcP-2 of A. crassispina and H. pulcherrimus were studied in developing embryos. The behavior of these forms in gel filtration changed during development, from unfertilized eggs to the pluteus stage.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120020209
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  • 10
    Electronic Resource
    Electronic Resource
    Isolation of bovine zonae pellucidae from ovaries with collagenase: Antigenic and sperm receptor properties (1979)
    New York, NY : Wiley-Blackwell
    Gamete Research 2 (1979), S. 187-192 
    Details
    ISSN: 0148-7280
    Keywords: zona isolation ; collagenase ; receptor for sperm ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Zonae pellucidae were collected from bovine ovaries by chopping, dispersing the chopped tissue with collagenase, sieving through nylon mesh screens, and pipetting. The zonae were free of corona cell processes when examined under the scanning electron microscope. Solutions of zonae obtained with collagenase exhibited the same antigenic and sperm receptor properties as those obtained without enzyme treatment.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120020210
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