Epigenetic modifications of the genome, such as covalent modification of histone residues, ensure appropriate gene activation during pre-implantation development, and are probably involved in the asymmetric reprogramming of the parental genomes after fertilization. We investigated the methylation patterns of histone H3 at lysine 9 (H3/K9), and the regulatory mechanism involved in the asymmetric...

The present study was carried out to examine the effect of maturation media on male pronucleus formation of pig oocyte matured and fertilized in vitro. Follicular oocytes collected from prepubertal gilts at a local slaughter house were cultured (36 h) in three different media (mTCM-199, Waymouth MB 752/l, and mTLP-PVA), fertilized in vitro, and assessed for nuclear maturation and male pronucleu...

We present a model of cytoplasmically-driven microtubule-based pronuclear motion in the single-celled C. elegans embryo. In this model, a centrosome pair at the male pronucleus initiates stochastic microtubule (MT) growth. These MTs encounter motor proteins, distributed throughout the cytoplasm, that attach and exert a pulling force. The consequent MT-length dependent pulling forces drag the pr...

Recent reports have suggested that when unfertilized oocytes with a spermatozoon after intracytoplasmic sperm injection (ICSI) are properly activated, the activated oocytes develop normally similar to fertilized oocytes. However, human oocytes do not easily respond to universal activators of mammalian oocytes like ethanol or calcium ionophore A23187, which induce a calcium transient in ooplasm....

During oocyte growth in the ovary, the nucleolus is mainly responsible for ribosome biogenesis. However, in the fully-grown oocyte, all transcription ceases, including ribosomal RNA synthesis, and the nucleolus adopts a specific monotonous fibrillar morphology without chromatin. The function of this inactive nucleolus in oocytes and embryos is still unknown. We previously reported that the embr...

Wolbachia is a bacteria endosymbiont that rapidly infects insect populations through a mechanism known as cytoplasmic incompatibility (CI). In CI, crosses between Wolbachia-infected males and uninfected females produce severe cell cycle defects in the male pronucleus resulting in early embryonic lethality. In contrast, viable progeny are produced when both parents are infected (the Rescue cross...

Sperm of the mouse, M us musculus, was X-irradiated in vitro before fertilization. Dosages were between 100 and 50 000 r. With increasing irradiation of the sperm, the chromosome complement of embryos, scored at 3ijr days’ gestation, declined from diploid to haploid. Higher dosages increasingly retarded embryonic development, 30000 and 50 000r restricting development to the first cleavage. Gyno...

background: testis tissue xenografting and the resultant sperm in a xenograft may provide a unique approach to rescue the genetic material of males that die prematurely and is a model for the study of human spermatogenesis and can represent an alternative approach for fertility preservation in cancer patients. this study was aimed to evaluate the xenogenic dog sperm in formation of male pronucl...

In this study, we have used time-lapse video cinematography to study fertilization in 50 human oocytes that had undergone intracytoplasmic sperm injection (ICSI). Time-lapse recording commenced shortly after ICSI and proceeded for 17-20 h. Oocytes were cultured in an environmental chamber which was maintained under standard culture conditions. Overall, 38 oocytes (76%) were fertilized normally,...