Fertilization is complete once the parental genomes unite, and requires the migration of the egg nucleus to the sperm nucleus (female and male pronuclei, respectively) on microtubules within the inseminated egg. Neither the molecular mechanism of pronucleus binding to microtubules nor the role of motor proteins in regulating pronuclear motility has been fully characterized, and the failure of z...

Major epigenetic modifications apparently occur during early development in the mouse. The factors that induce such modifications are complex and may involve the various components of a zygote. We have started to explore whether changes in the nucleocytoplasmic composition brought about by micromanipulation can induce phenotypic effects through epigenetic modifications. Nucleocytoplasmic hybrid...

BACKGROUND Identification of embryos with high implantation potential remains a challenge in in vitro fertilization (IVF). Subjective pronuclear (PN) zygote scoring systems have been developed for that purpose. The aim of this work was to provide a software tool that enables objective measuring of morphological characteristics of the human PN zygote. METHODS A computer program was created to ...

BACKGROUND The aim of this study was to examine whether the integrity rate of pronuclei, after cryopreservation of pronuclear zygotes, could be a predictor of future embryo development and implantation. METHODS Two-pronuclei stage zygotes (n = 862) were cryopreserved by aseptic rapid freezing in 15% ethylene glycol + 15% DMSO + 0.2 M sucrose with a 4-step exposure in 12% (v:v), 25, 50 and 100...

We studied the presence and distribution of the intracellular calcium channel regulating type I inositol 1,4,5-trisphosphate receptors (IP3R) in human immature and mature oocytes, pronuclear zygotes and cleaved embryos using a specific antibody. Two approaches were used: (i) fluorescence immunocytochemistry using a confocal laser scanning microscope (CLSM) and (ii) Western blotting. With confoc...

BACKGROUND The basal medium that supports Isolated Mouse Oviduct (IMO) is important for supporting embryo development and quality. METHODS The culture of ovine IVM/IVF zygotes was done in IMO using SOFaaciBSA and SOFaaBSA as basal medium of IMO and in SOFaaBSA alone as control. For preparation of IMO mature inbred strain C57BL/6 female mice were synchronized and mated with vasectomized males....

In angiosperms, the conversion of an egg cell into a zygote involves two sequential gametic processes: plasmogamy, the fusion of the plasma membranes of male and female gametes, and karyogamy, the fusion of the gametic nuclei. In this study, the nuclei and nuclear membranes of rice (Oryza sativa) gametes were fluorescently labeled using histones 2B-green fluorescent protein/red fluorescent prot...

The large, compactoocytenucleoli, sometimes referred toasnucleolus precursor bodies (NPBs), are essential for embryonic development in mammals; in their absence, the oocytes complete maturation and can be fertilized, but no nucleoli are formed in the zygote or embryo, leading to developmental failure. It has been convincingly documented that zygotes inherit the oocyte nucleolarmaterial and form...

BACKGROUND: The aim was to study zygote evaluation based on pronuclear morphology under the German embryo protection law, according to which only a maximum of three zygotes are allowed to be cultured for embryo transfer. METHODS: In this prospective multicentre study, a total of 512 treatment cycles was performed at 10 centres, between November 1999 and October 2000. Zygotes were classified int...

BACKGROUND Series of epigenetic events happen during preimplantation development. Therefore assistant reproduction techniques (ART) have the potential to disrupt epigenetic regulation during embryo development. The purpose of this study was to investigate whether defects in methylation patterns in blastocyst due to superovulation originate from abnormal expression of Dnmts. METHODS Low- (6 IU...