Previous reports have indicated that failure in cloning monkey is attributed to the removal of nuclear mitotic apparatus (NuMA) during enucleation and subsequent abnormal organization of mitotic apparatus. This study investigated the transformation and assembly of tubulin and NuMA protein during the first cell cycle of cloned monkey embryos reconstructed by using enucleated rabbit oocytes as re...

Results of several lines of experimentation suggest that sperm-induced egg activation has several features in common with G protein-coupled receptor signal transduction mechanisms. We report that microinjection of GDP beta S into metaphase II-arrested mouse eggs blocks sperm-induced egg activation. Since GDP beta S inactivates both heterotrimeric and monomeric classes of G proteins, the involve...

variant, known as mottled or kandiyohi, occurs in populations of the common A leopard frog, Rana pipiens, in Minnesota and other north-central states (BRECKENRIDGE 1944; WRIGHT and WRIGHT 1949). The kandiyohi frog was described originally as a new species (WEED 1922), but genetic studies (VOLPE 1955) have revealed that it differs from the wild-type frog by a single dominant gene. The kandiyohi ...

Eggs from (C57B1 x A a G ^ mice were activated by treatment with hyaluronidase, which removed the follicle cells, and cultured in vitro. Observations were made 6-8 h after hyaluronidase treatment to determine the frequency of activation and the types of parthenogenones induced. Cumulus-free eggs resulting from hyaluronidase treatment were incubated for 2\ h in culture media of various osmolarit...

The main question addressed in this thesis is what happens between the moment when the sperm enters the egg and the fusion of the male and the female pronuclei. Orientation of the apposing pronuclei most likely plays a decisive role in the polarity of the developing embryo. The migration and the dependence between the pronuclei have been investigated through three different measures of correlat...

Effects of recipient oocyte activation methods on the development of nuclear transfer (NT) embryos were investigated. In Exp. 1, cell-cycle phase of serum-starved bovine cumulus cells was examined by flow cytometry. Majority (95.5%) of medium-sized (16-20 microm) cells that made up 56% of total cells was at the G0/G1 phase. NT embryos were constructed by electric fusion with the medium-sized se...

The microinjection method for production of transgenic farm animals requires specialized techniques and results in intolerably low production efficiencies. We investigated whether or not co-injection of foreign DNA constructs with restriction endonuclease into the pronucleus of mouse zygotes would improve the integration frequencies of foreign DNA into the host genome. Two kinds of DNA construc...