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  • Life and Medical Sciences  (3)
  • Electronic structure and strongly correlated systems
  • 1975-1979  (3)
  • 1
    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
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  • 2
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sexual dimorphism in the distribution of antennal sense organs is common among adults of the genus Periplaneta. In three out of the four strains of Periplaneta americana examined, adult males had more contact chemoreceptors than females. In the fourth strain of P. americana and in P. australasiae, P. brunnea, P. fuliginosa, and P. japonica, no statistically supportable sexual dimorphism of contact chemoreceptors was found. However, in all strains and species of Periplaneta examined, sexual dimorphism was found in the total number and/or density of olfactory sensilla. Male adults had nearly twice as many olfactory sensilla as female adults. These observations are consistent with the behavioral observation that males within the genus Periplaneta rely on the reception of an airborne pheromone for the initiation of courtship behavior. In P. americana, where sexual dimorphism was found in the contact chemoreceptors, contact stimuli release the full wing raising display and presentation in males during courtship.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 153 (1977), S. 153-161 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mature ovary of Gastrotheca riobambae presents large oocytes (3 mm in diameter) of pale yellow color. After ovulation and the beginning of embryonic incubation, the empty postovulatory follicles can be recognized in the ovary for about 30 days. The granulosa of these follicles never fills the follicular lumen and this cavity becomes filled with fluid during the first five days of incubation. Later, at 18 days of incubation, the lumen is mostly empty and contains few cells of the granulosa. Shrinkage results in the disappearance of the follicular cavity by approximately the thirtieth day of incubation. The thecae are thick and become separated by a space. This space is filled progressively with cells, blood capillaries and fluid. After the thirtieth to fortieth day of incubation, these follicles become regressive and disappear. The postovulatory follicles of Gastrotheca may correspond to corpora lutea. The evidence suggests that pouch vascularization and the formation of embryonic chambers of pouch tissue may be under ovarian control. In addition, the process of vitellogenesis is influenced by incubation, as most growth of the ovarian oocyte occurs after birth of the tadpoles. Follicular atresia is common and is similar to that of other frogs.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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