نتایج جستجو برای: pronuclear formation
تعداد نتایج: 527908 فیلتر نتایج به سال:
We have used a bovine papillomavirus-based vector to generate transgenic mice. Transgenic mice result from either pronuclear or cytoplasmic injections of the vector into fertilized eggs. Of 30 mice generated by microinjection, 27 (90%) contained the vector in its episomal form, at less than one copy per cell. This represents a highly efficient means of gene transfer in which the transgene is in...
In an overwhelming majority of experiments, both mammalian embryonic and somatic cloning have relied on introducing exogenous nuclei into enucleated metaphase II (MII) oocytes. Since attempts at cloning using interphase zygotes as recipient cells have failed, these cells were – until quite recently – commonly regarded as poor recipients for nuclear transfer. However, we have recently shown that...
In vitro-matured (IVM) bovine oocytes were activated with single and combined treatments of strontium (S), ionomycin (I) and 6-DMAP (D). Using oocytes IVM for 26 h, we observed that activation altered cell cycle kinetics (faster progression, MIII arrest, or direct transition from MII to pronuclear stage) when compared to in vitro fertilization. The effect of oocyte age on early parthenogenesis ...
Eggs of the sea urchin, Arbacia punctulata, treated with 3% urethane for 30 sec followed by 0.3% urethane and inseminated are polyspermic and fail to undergo a typical cortical reaction. Upon insemination the vitelline layer of urethane-treated eggs either does not separate or is raised only a short distance from the oolemma. 1-6 min after insemination, almost all of the cortical granules remai...
BACKGROUND The initiation of a cleavage furrow is essential to separate cells during cytokinesis, but little is known about the mechanisms controlling this actin-driven process. Previous studies in C. elegans embryos revealed that inactivation of the CUL-3-based E3 ligase activator rfl-1 results in an aberrant microtubule network, ectopic furrowing during pronuclear migration, and defects durin...
OBJECTIVES In the past several scoring systems were proposed for early human development aiming to assist in the identification of the best embryos. Scoring criteria are usually assessed at static developmental time points by microscopy. For almost every scoring system controversial results on its benefit can be found in the literature. With the introduction of time-lapse imaging static assessm...
After fertilization, the sperm and oocyte genomes undergo extensive epigenetic reprogramming to form a totipotent zygote. The dynamic epigenetic changes during early embryo development primarily involve DNA methylation and demethylation. We have previously identified Gse (gonad-specific expression gene) to be expressed specifically in germ cells and early embryos. Its encoded protein GSE is pre...
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