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|Title:||Effects of Interactions of Gamete Aging|
|Author(s):||Smith, Albert Louis|
|Department / Program:||Dairy Science|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Subject(s):||Agriculture, Animal Culture and Nutrition|
|Abstract:||Effects of interactions of 0-24 hr in vitro aged sperm and 0-24 hr in vivo aged ova on fertilization were studied, utilizing in vitro fertilization in the mouse as a model system. Stages of fertilization examined were penetration, pronuclear, and prometaphase. Anomalies such as polynuclear embryos and scattering of nuclear material were also noted.
At penetration, significant sperm aging, egg aging, and sperm aging x egg aging interaction effects were detected. The sperm aging effect was attributed to reduced ability of the sperm to penetrate the ova, due to decreased motility, metabolism, and/or enzyme content of the acrosome. The egg aging was attributed to alterations in the outer membranes of the ovum, making it more impenetrable to sperm. The sperm aging x egg aging interaction was attributed to decreased penetrability of aged ova combined with a decreased ability of aged sperm to penetrate ova.
At the pronuclear stage of development, a non-significant sperm aging effect, a significant egg aging effect, and a significant sperm aging x egg aging interaction were detected. It was hypothesized that the quality of sperm chromatin is unimportant in the initiation of the pronuclear stage. The significant egg aging effect was attributed to increased activity of cytoplasmic factors or nuclear-mediated cytoplasmic factors necessary for pronuclear development. The significant sperm aging x egg aging interaction was postulated to be due to the difference in the magnitude of response of egg aging over sperm aging.
At prometaphase of fertilization, a significant sperm aging effect, along with a significant sperm aging x egg aging interaction were detected. It was proposed that aged sperm are capable of pronuclear development, but, at a certain point, become incapable of subsequent development to prometaphase stage. The significant sperm aging x egg aging interaction was attributed to an increased asynchrony of development between male and female pronuclei which leads to asynchrony of chromosome groups at prometaphase.
No significant sperm aging effects, egg aging effects, or sperm aging x egg aging interactions were detected in fertilized ova which were polynuclear or had scattered chromatin material. Formation of polynuclear embryos and scattering of chromatin material was hypothesized to be a response of certain ova from certain females, independent of the aging process. It was also proposed that some aberrations associated with gamete aging result from post-fertilization cleavage errors.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1981.
|Date Available in IDEALS:||2014-12-16|