Only 25 to 30% of conceptions result in a live birth. There is mounting evidence that the cause for this low fecundity is an extremely high incidence of chromosomal rearrangements occurring in the cleavage stage embryo. In this review, we gather all recent evidence for an extraordinary degree of mosaicisms in early embryogenesis. The presence of the rearrangements seen in the cleavage stage emb...

The changing nature of intercellular coupling during the 4- and 8-cell stages of mouse early development has been investigated by iontophoretic injection of carboxyfluorescein, horseradish peroxidase and current into individual blastomeres in either the intact embryo or after their disaggregation and reaggregation into pairs. Coupling junctions that allowed only molecules of low molecular weigh...

The transition from egg to embryo occurs in the absence of transcription yet requires significant changes in gene activity. Here, we show that the C. elegans DYRK family kinase MBK-2 coordinates the degradation of several maternal proteins, and is essential for zygotes to complete cytokinesis and pattern the first embryonic axis. In mbk-2 mutants, the meiosis-specific katanin subunits MEI-1 and...

As production of in vitro (IVP) bovine embryos steadily increases, the sanitary risk associated with IVP embryos remains a concern. One of the greatest concerns is how BVDV may be transmitted through IVP embryos. The objective of this study was to evaluate the effects caused by BVDV-1, BVDV-2 and Hobi-like virus exposure during in vitro maturation on embryo development and viral infection. Abit...

During early cleavages of Sicyonia ingentis embryos, mitotic spindle orientations differ between blastomeres and change in a predictable manner with each successive mitosis. From 2nd through 7th cleavages, spindles orient at a 90 degrees angle with respect to the spindle of the parent blastomere. Thus, spindle orientation is parallel to the cleavage plane that formed the blastomere. To determin...

sperm chromatin integrity has been being recognized as an important factor in male fertility. during normal fertilization, high quality sperm with intact chromatin are selected through natural selection in journey from vagina to fallopian tube. however, using assisted reproductive techniques, particularly icsi, the natural selection is bypassed. therefore sperm with dna breakage have the opport...

BMP signaling is modulated by a number of extracellular proteins, including the inhibitor Chordin, Tolloid-related enzymes (Tld), and the interacting protein Twisted Gastrulation (Tsg). Although in vitro studies have demonstrated Chordin cleavage by Tld enzymes, its significance as a regulatory mechanism in vivo has not been established in vertebrates. In addition, Tsg has been reported in diff...

De novo formation of cells in the Drosophila embryo is achieved when each nucleus is surrounded by a furrow of plasma membrane. Remodeling of the plasma membrane during cleavage furrow ingression involves the exocytic and endocytic pathways, including endocytic tubules that form at cleavage furrow tips (CFT-tubules). The tubules are marked by amphiphysin but are otherwise poorly understood. Her...

Abstract Study question Establishment of prediction model pregnancy rate and live birth in vitro fertilization-embryo transfer Summary answer the calibration degree is good, it a relatively ideal outcome. What known already The clinical has some differences between average probability actual occurrence IVF-ET patients, but design, size, duration statistically significant influencing factors wer...

The pattern of the earliest cell divisions in a vertebrate embryo lays the groundwork for later developmental events such as gastrulation, organogenesis, and overall body plan establishment. Understanding these early cleavage patterns and the mechanisms that create them is thus crucial for the study of vertebrate development. This chapter describes the early cleavage stages for species represen...