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Blastocyte

The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform

Gregory R D Evans – 1st expert on this subject based on the ideXlab platform

  • generation of induced pluripotent stem ips cells by nuclear reprogramming
    Stem Cells International, 2011
    Co-Authors: Gregory R D Evans

    Abstract:

    During embryonic development pluripotency is progressively lost irreversibly by cell division, differentiation, migration and organ formation. Terminally differentiated cells do not generate other kinds of cells. Pluripotent stem cells are a great source of varying cell types that are used for tissue regeneration or repair of damaged tissue. The pluripotent stem cells can be derived from inner cell mass of Blastocyte but its application is limited due to ethical concerns. The recent discovery of iPS with defined reprogramming factors has initiated a flurry of works on stem cell in various laboratories. The pluripotent cells can be derived from various differentiated adult cells as well as from adult stem cells by nuclear reprogramming, somatic cell nuclear transfer etc. In this review article, different aspects of nuclear reprogramming are discussed.

Li Yuqiang – 2nd expert on this subject based on the ideXlab platform

  • Bovine Somatic Cell Nuclear Transplantation by Intraplasmic Injection
    Chinese Journal of Animal and Veterinary Sciences, 2020
    Co-Authors: Li Yuqiang, An Zhixing, Zhang Yong

    Abstract:

    The effect of donor cell cycle, cell hypotonic treatment and recipient oocytes meiosis phase on development of bovine somatic cell nuclear transfer embryos was studied in the present experiment. Oocyte intraplasmic nuclear injection was used as embryo reconstruction method. The results indicated that: There was no significant effect of culturing bovine skin fibroblasts with 0.5% FBS media (attached quiescent cell) on the development of bovine nuclear transfer embryos as compared with non-quiescent cell (P0.05).Treatment of donor cells with 0.1% sodium citric acid 20 s before nuclear injection was beneficial for cell membrane breakdown and nuclear dissociation, as a result , the nuclear transfer embryos development rate to 8/16-cell stage and Blastocytes was significantly higher than control(P0.01).It was found that donor cells suspended in 0.5% FBS TCM199 3 d (suspended quiescent cell) could make it easily to dissociate nuclear without hypotonic treatment, and development ability of the nuclear transfer embryos was also promoted slightly. The TⅡ oocyte (activation before nuclear injection)or MⅡoocyte (activation after injection) did not significantly affect the development of nuclear transfer embryos. Our findings suggest that donor nuclear dissociation efficiency was crucial to the sucsses of oocyte intraplasmic injection, suspension quiescence was a proper donor cell treatment method,both TⅡoocytes and MⅡ oocytes could be used as recipient.

  • Effect of Oocyte Maturation in Vitro on Bovine Parthenogenetic Embryo Development Competence
    Journal of Yellow Cattle Science, 2020
    Co-Authors: Zhang, Li Yuqiang, Zhang Yong, Wang Chao, Li Xiang-chen, Zhang Zhiping

    Abstract:

    Based on maturation in vitro of bovine oocytes, our research mainly focused on the effect of oocyte maturation in vitro on parthenogenetic embryos development competence in bovine. The results showed that The development rate to the blastocyst stage of oocytes activated after maturation for 22~24 h in medium prepared with Milli-Q water (29.7%) was significantly higher than with three-distilled water (14.1%, P0.05). The addition of 10% or 20% BFF (bovine follicle fluid) in maturation medium obtained higher blastocyst rate (32.3% or 30.9%) than that in 5% or control treatment (21.8% or {22.7%}, P0.05). In addition, the addition of 20% BFF in maturation medium inhibited the hatching of blastocyst. It suggested that oocytes matured for 28 h or 30 h before pathenogenetic activation resulted in higher Blastocyte rate (30.5% or 29.4%) than those matured for 24 h or 26 h (20.5% or 22.1%, P{0.05}).;

  • Discussion on in vitro production(IVP) and development of bovine early embryos
    Heilongjiang Animal Science and Veterinary Medicine, 2006
    Co-Authors: Li Yuqiang

    Abstract:

    The aim of these experiments was to investigate the effect of fertilization medium,coincubation of oocytesperm,serum and embryo culture medium on in vitro production of embryos(IVP).The results indicated that oocytes fertilized in BM(BO∶TCM199=3∶2) medium had significantly higher blastocyst formation rate(26.0%)than that in BO medium(15.0 %).Coincubation of oocyte[CD*2]sperm for 9~12 h was better than any other time.Presumptive zygotes were cultured in mSOFaa medium supplemented with OCS(oestrus cow serum) or FBS had higher Blastocyte yield(26.4%,29.9%) than that in culture medium with free serum(10.3%).MSOFaa,mBECMaa,and TCM199 medium all could support early fertilized embryo developing to Blastocyte stage in vitro(29.2%,30.7% vs.18.0%).The results showed that it was a proper system for IVP that presumptive zygotes were cultured in mSOFaa or mBECMaa with 5%OCS after oocytesperm co[CD*2]incubation for 9 to 12 h in BM media.

Kevin D. Sarge – 3rd expert on this subject based on the ideXlab platform

  • RNA Polymerase II interacts with the Hspa1b Promoter in Mouse Epididymal Spermatozoa
    Reproduction, 2009
    Co-Authors: Dennis Charles Wilkerson, Kevin D. Sarge

    Abstract:

    The Hspa1b (Hsp70.1) gene is one of the first genes expressed after fertilization, with expression occurring during the minor zygotic genome activation in the absence of stress. This expression can take place in the male pronucleus as early as the one-cell stage of embryogenesis. The importance of HSPA1B for embryonic viability during times of stress is supported by studies showing that depletion of this protein results in a significant reduction in embryos developing to the Blastocyte stage. Recently we began addressing the mechanism responsible for allowing expression of Hspa1b during the minor ZGA and found that HSF1 and HSF2 bind the Hspa1b promoter during late spermatogenesis. In this report, we have extended those studies using western blots and chromatin immunoprecipitation assays and found that RNA Polymerase II is present in epididymal spermatozoa and bound to the Hspa1b promoter. These present results, in addition to our previous results, support a model in which the binding of HSF1, HSF2, Sp1, and RNA Polymerase II to the promoter of Hspa1b would allow the rapid formation of a transcription-competent state during the minor ZGA, thereby allowing Hspa1b expression.

  • interaction of hsf1 and hsf2 with the hspa1b promoter in mouse epididymal spermatozoa
    Biology of Reproduction, 2008
    Co-Authors: Dennis Charles Wilkerson, Lynea A Murphy, Kevin D. Sarge

    Abstract:

    The Hspa1b gene is one of the first genes expressed after fertilization, with expression observed in the male pronucleus as early as the one-cell stage of embryogenesis. This expression can occur in the absence of stress and is initiated during the minor zygotic genome activation. There is a significant reduction in the number of embryos developing to the Blastocyte stage when HSPA1B levels are depleted, which supports the importance of this protein for embryonic viability. However, the mechanism responsible for allowing expression of Hspa1b during the minor zygotic genome activation (ZGA) is unknown. In this report, we investigated the role of HSF1 and HSF2 in bookmarking Hspa1b during late spermatogenesis. Western blot results show that both HSF1 and HSF2 are present in epididymal spermatozoa, and immunofluorescence analysis revealed that some of the HSF1 and HSF2 proteins in these cells overlap the 4′,6′-diamidino-2-phenylindole-stained DNA region. Results from chromatin immunoprecipitation assays showed that HSF1, HSF2, and SP1 are bound to the Hspa1b promoter in epididymal spermatozoa. Furthermore, we observed an increase in HSF2 binding to the Hspa1b promoter in late spermatids versus early spermatids, suggesting a likely period during spermatogenesis when transcription factor binding could occur. These results support a model in which the binding of HSF1, HSF2, and SP1 to the promoter of Hspa1b would allow the rapid formation of a transcription-competent state during the minor ZGA, thereby allowing Hspa1b expression.