Adult ; Chromatids/genetics* ; Chromosome Aberrations ; Humans ; Infertility, Male/genetics* ; Male ; Meiosis ; Metaphase/genetics* ; Spermatocytes/physiology*

Humans ; Male ; Metaphase/physiology* ; Sex Chromosomes/ultrastructure* ; Spermatocytes/ultrastructure* ; Spermatogenesis ; Testis/ultrastructure*

Nano-cryopreservation may become a new way in the next generation of cryopreservation technology. However, research using nanoparticles in oocytes vitrification has not been reported in the literature. In this study, HA nanoparticles with different diameters were added into cryoprotectant and M II-stage porcine oocytes were vitrified by Cryotop. The results showed that nanoparticles improved the survival rate of cryopreserved M II-stage porcine oocytes, but the difference between nanoparticles with different diameters of was not significant. In order to study the mechanism of nano-cryopreservation, the cooling rate of cryoprotectant was measured by ultra-fast temperature measurement system and the melting enthalpy of cryoprotectant was measured by differential scanning calorimeter (DSC). The results showed that the adding of nanoparitcles could not increase the cooling rate of cryoprotectant, but could decreases the amount of ice crystals during freezing and warming. Therefore, the mechanical injury within and outside cells might be effectively reduced.
Animals ; Cell Survival ; physiology ; Cryopreservation ; methods ; veterinary ; Cryoprotective Agents ; pharmacology ; Durapatite ; pharmacology ; Female ; Fertilization in Vitro ; methods ; veterinary ; Metaphase ; Nanoparticles ; Oocytes ; cytology ; Swine ; Vitrification

Chfr, a mitotic stress checkpoint gene, regulates a prophase delay in cells exposed to agents that disrupt microtubules, such as nocodazole and taxol. Chfr expression was ubiquitious in normal human tissues. It is very high conserved between human and mice. Preliminary sutdies indicated that Chfr expression was cell cycle regulated and it dependent on its ubiqitin ligase activity. The direct target of the Chfr pathway was Polo-like kinase 1 (Plk1). Ubiquitination of Plk1 by Chfr delayed the activation of the Cdc25C phosphatase and the inactivation of the Weel kinase, leading to a delay in Cdc 2 activation. The chfr gene was inactivated owing to lack of expression or by mutation in some human cancer cell lines examined. Normal primary cells and tumour cell lines that express wild-type chfr exhibited delayed entry into metaphase when centrosome separation was inhibited by mitotic stress. In contrast, the tumour cell lines that had lost chfr function entered metaphase without delay. Ecotopic expression of wild-type chfr restored the cell cycle delay and increased the ability of the cells to survive mitotic stress. Thus, chfr defines a checkpoint that delays entry into metaphase in response to mitotic stress. The progress of research on structure of Chfr gene and effects of Chfr protein was reviewed.
Cell Cycle ; genetics ; physiology ; Cell Cycle Proteins ; genetics ; metabolism ; physiology ; Humans ; Metaphase ; genetics ; physiology ; Mitosis ; genetics ; physiology ; Neoplasm Proteins ; genetics ; physiology ; Neoplasms ; genetics ; metabolism ; pathology ; Poly-ADP-Ribose Binding Proteins ; Prophase ; genetics ; physiology ; Protein-Serine-Threonine Kinases ; metabolism ; Protein-Tyrosine Kinases ; metabolism ; Proto-Oncogene Proteins ; metabolism ; Ubiquitin-Protein Ligases

Sec13p has been known as an endoplasmic reticulum-Golgi transport protein. Recently, it has also been shown to be required for the formation of septation in the fission yeast Schizosaccharomyces pombe. In the present study, we focused on the role of a human homolog of Saccharomyces cerevisiae SEC13, Sec13 protein during mitosis in U2OS cells. We found that the expression of Sec13 was constant throughout the cell cycle, and localized to the kinetochores at metaphase during mitosis. By using green fluorescent protein technology, we observed that Sec13 is required for evasion of mitotic arrest in response to spindle damage, leading to G1-like phase and apoptotic cell death. In addition, cells expressing exogenous Sec13 showed giant nuclei compared to endogenous ones in the absence of nocodazole. These results demonstrate that Sec13 is involved in the regulation of the metaphase/anaphase transition and may be functionally associated with mitotic machinery to maintain genomic stability during mitosis.
Anaphase ; Antineoplastic Agents/pharmacology ; Cell Line, Tumor/drug effects/metabolism/pathology ; *G1 Phase ; *Genomic Instability ; Green Fluorescent Proteins/metabolism ; Humans ; Kinetochores/metabolism ; Membrane Proteins/*genetics/metabolism ; Metaphase ; Mitosis/*physiology ; *Mitotic Spindle Apparatus ; Nocodazole/pharmacology ; Osteosarcoma/genetics/metabolism/pathology ; Research Support, Non-U.S. Gov't