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随着辅助生殖技术的发展,配子与胚胎的超低温冷冻保存已成为动物种质资源保存的新热点,有可能在相当程度上替代活畜保种。但由于猪卵母细胞中含有大量脂滴,对低温敏感,耐受性差,给猪卵母细胞的冷冻保存带来很大的困难。目前还没有关于猪卵母细胞冷冻-解冻后经体外受精,然后移植产仔的成功报道,其原因可能是冷冻破坏了细胞骨架的结构。因此本文主要分析了冷冻保存对猪卵母细胞细胞骨架及其冻融后发育潜力的影响。 相似文献
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体外胚胎冷冻保存技术是胚胎移植技术的重要组成部分,在辅助生殖技术中发挥重要作用,同时对种质资源保存、加强遗传改良和促进优质种源国际交流等方面具有重要意义。然而,体外胚胎冷冻过程中存在脂质含量过高、活性氧水平升高及机械损伤等问题,导致体外胚胎冷冻效率低,这极大地限制了体外胚胎冷冻保存技术的广泛应用。大量研究表明,通过去脂质、优化体外胚胎培养液、人工塌陷囊胚腔和优化冷冻程序等手段,可以有效提高冷冻后胚胎的存活率和发育能力。因此,本文概述了体外胚胎冷冻保存技术的研究进展和胚胎冷冻过程中存在的问题,总结了提高体外胚胎冷冻效率的方法措施,旨在为提高体外胚胎冷冻保存效率提供一定参考。 相似文献
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繁殖生物技术,亦称人工辅助繁殖技术(ART)。人工授精、胚胎移植以及所有围绕配子和胚胎进行的操作技术都属此范畴。本文简述犬的ART的进展,主要集中在人工授精、卵母细胞体外成熟、体外受精、胚胎体外培养、胚胎冷冻保存和胚胎移植等方面,并对今后的发展,尤其是对我国犬的繁殖技术研究和应用,提出一些观点和想法。一、犬繁殖生物技术的进展和现状(一)精液冷冻和人工授精第一次有关犬的精液处理和短期保存研究出现在1960年。此后,逐渐开发和改进了犬精子冷冻保存的方法。1969年,第一批冷冻精液人工授精犬仔在美国诞生。至今,在世界范围内… 相似文献
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自 2 0世纪 70年代小鼠的胚胎成功冷冻以来 ,在动物胚胎冷冻保存方面进行了广泛的研究。目前 ,胚胎的冷冻保存已成为胚胎移植的常规技术环节之一。本文就动物的胚胎冷冻保存的原理、冷冻保护剂的选择和主要的冷冻方法及影响冷冻效果的因素等方面进行了详细的综述。并就各冷冻方法的优缺点进行了探讨 ,旨在使胚胎冷冻保存技术在畜牧业生产中得到更为广泛的应用和推广。 相似文献
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配子（精子和卵子）冷冻保存是将配子在超低温条件下冷冻,可进行优秀家畜个体和珍稀濒危动物种质资源的长期保存。配子冷冻是珍稀濒危动物种质资源保护、保存和利用的一项重要内容,也是动物种质资源库建设的一项关键技术。本文对国内外精子和卵母细胞冷冻保存利用技术的研究现状进行了详细论述,同时介绍了配子冷冻-解冻后的损伤评估研究,提出了未来我国在濒危珍稀动物配子冷冻保存方面的应用策略和保种建议,以期为我国家畜生物种质资源库建设、家畜种质资源保护和开发利用以及珍稀濒危动物保护提供参考。 相似文献
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自从 Polgy、Wmith 和 Porkes 首次发现冷冻保存精子的方法后,就引起了繁殖工作者冷冻保存哺乳动物卵子和胚胎的兴趣。1972年 Whittmghan 首次报道鼠胚胎冷冻成功,在-196℃保存小鼠胚胎移入受体有29%产仔。不久,Wilmut 也报道了鼠胚胎冷冻成功。1973年 Wilnnut 和 Rosuson 第一次报道冷冻牛胚胎得到一头犊牛。从此,冷冻保存哺乳动物胚胎的研究才不断开展。开始,对实验室动物研究较多,后来转到了家畜方面,迄今已用冷冻保 相似文献
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Cryopreservation of mammalian germ cells and embryos has been widely used in assisted reproduction. It also plays an important role in preservation of species diversity. DNA methylation abnormality induced by freezing in germ cells or embryos has an significant impact on the occurrence of disease and the physiological function of the offspring. In this paper, we summarize the effects of cryopreservation of mammalian germ cells and embryos on their pattern of DNA methylation which in turn make the developmental deficiency in the progeny from these gametes or embryos. Finally, it will provide the reference on the gamete cryopreservation and the development of assisted reproductive technology. 相似文献
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Recent improvements in cryopreservation of mammalian eggs enable the long-term preservation of female germ cells in several mammalian species. Nevertheless, cryopreservation of porcine oocytes is still considered as a challenge. Although the use of vitrification techniques result in reasonable survival rates, developmental competence of vitrified oocytes has been compromised. Alterations of zona characteristics, cytoskeleton, mitochondrial functions and antioxidant-defense ability caused by vitrification are among the most frequently observed malformations which may be responsible for the low developmental competence of cryopreserved porcine oocytes. Furthermore, in vitro maturation, fertilization and embryo culture technologies, which are indispensable for generating embryos from cryopreserved oocytes, generate high rates of abnormal fertilization (polyspermy) and additional stress in resultant embryos further compromising their developmental competence. As a result, embryo development of porcine cryopreserved oocytes is still at low level and to date no piglet has been produced from such oocytes. The aim of the present review is to summarize knowledge on viability and developmental competence of vitrified porcine oocytes and to give ideas for future perspectives for the improvement of porcine oocyte cryopreservation technology. 相似文献
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DNA甲基化(DNA methylation)是一种动态、可逆并可以遗传的表观遗传修饰模式,主要发生在哺乳动物原始生殖细胞和早期胚胎发育过程中,能够通过高动态和协同的核酶网络附着在DNA的CpG区域,同时还通过改变调控区域的功能状态进而调控基因表达且不影响DNA序列所携带的遗传信息。DNA甲基化主要涉及基因组印迹、转座元件沉默、X染色体失活和衰老等多种关键生理过程,在哺乳动物卵母细胞和胚胎发育中发挥着重要作用。本文介绍了DNA甲基化的建立与去除机制及其生物学功能,重点阐述了DNA甲基化在哺乳动物卵母细胞和胚胎发育过程中精准生成、维持、读取和删除等动态变化过程,为进一步研究哺乳动物表观遗传调控提供参考依据。 相似文献
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Mitsuru NAITO 《Animal Science Journal》2003,74(3):157-168
The development of chicken embryo culture techniques, from single‐cell stage to hatching, makes it possible to manipulate developing embryos at any developmental stage. Production of germline chimeric chickens by the transfer of stage X blastodermal cells or primordial germ cells enables the manipulation of germline cells in vitro. Production of transgenic chickens has been attempted by the retroviral vector method, microinjection of DNA into a fertilized ovum at the single‐cell stage, use of chimeric intermediates produced by the transfer of stage X blastodermal cells or primordial germ cells, manipulation of spermatozoa, and in vivo manipulation of gonads. So far, the only non‐viral method that has successfully produced transgenic chickens is microinjection of DNA into a fertilized ovum. Manipulation of primordial germ cells could become an efficient system for producing transgenic chickens by combining it with the highly efficient transfection method or the in vitro culture system for primordial germ cells. Preservation of avian genetic resources has now become possible by cryopreservation of stage X blastodermal cells or primordial germ cells as well as spermatozoa. The development of nuclear transfer techniques for avian species is necessary. 相似文献
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Horii T Suetake I Yanagisawa E Morita S Kimura M Nagao Y Imai H Tajima S Hatada I 《The Journal of reproduction and development》2011,57(5):579-585
Manipulation of preimplantation embryos in vitro, such as in vitro fertilization (IVF), in vitro culture (IVC), intracytoplasmic sperm injection (ICSI), somatic cell nuclear transfer (SCNT) and other assisted reproduction technologies (ART), has contributed to the development of infertility treatment and new animal reproduction methods. However, such embryos often exhibit abnormal DNA methylation patterns in imprinted genes and centromeric satellite repeats. These DNA methylation patterns are established and maintained by three DNA methyltransferases: Dnmt1, Dnmt3a and Dnmt3b. Dnmt3b is responsible for the creation of methylation patterns during the early stage of embryogenesis and consists of many alternative splice variants that affect methylation activity; nevertheless, the roles of these variants have not yet been identified. In this study, we found an alternatively spliced variant of Dnmt3b lacking exon 6 (Dnmt3bΔ6) that is specific to mouse IVC embryos. Dnmt3bΔ6 also showed prominent expression in embryonic stem (ES) cells derived from in vitro manipulated embryos. Interestingly, IVC blastocysts were hypomethylated in centromeric satellite repeat regions that could be susceptible to methylation by Dnmt3b. In vitro methylation activity assays showed that Dnmt3bΔ6 had lower activity than normal Dnmt3b. Our findings suggest that Dnmt3bΔ6 could induce a hypomethylation status especially in in vitro manipulated embryos. 相似文献
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利用低温生物学与人工辅助生殖技术（ART）保护生物资源,被证明是保护野生动物遗传资源的有效手段之一。野生动物的种质（卵母细胞、精子）或胚胎,相关的组织（卵巢、睾丸或附睾等）和体细胞均可以在-196℃超低温的环境下长期保持。人工辅助生殖技术除低温生物学技术外,还包括：人工授精技术;卵母细胞的体外成熟技术;体外受精技术以及胚胎移植;产前诊断等众多复杂的技术。但是,应用于野生动物的低温生物学和ART与应用与经济动物和实验动物时有很大差异,特别是某些需保种的珍稀或濒危野生动物数量有限,野生动物冷冻保种时有许多技术困难急待克服。例如：野生动物种质冷冻样品的采集问题;各种野生动物冷冻胚胎和冷冻精子时可能采取的最佳冷冻保护程序及不同的冷冻保护剂。特别是如何选取适当的野生动物受体成为制约其发展的一个瓶颈。 相似文献
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Although cryopreservation experiments with mammalian embryos have been performed for more than 30 years, definite progress was only achieved in the seventies. Investigations with mouse embryos have mainly contributed to the establishment of cryopreservation procedures for livestock embryos. Today the freezing of sheep and cattle embryos is applied to practice, but still transfer results range about 10% to 15% below comparable results obtained from transfer with fresh embryos. Procedures for the cryopreservation of mammalian oocytes and subsequent in-vitro fertilization of frozen/thawed oocytes are just being developed. Until now, only in the mouse a reproducable method for this purpose has been found. Meanwhile children were born from human in-vitro fertilization programs after cryopreservation of oocytes as well as embryos, although the cryopreservation of human embryos is facing major ethical objections. 相似文献
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Biodiversity is increasingly threatened by intensive agriculture, environmental pollution, extinction of natural habitats and several other factors. Several mammalian species including ungulates have disappeared or are threatened by extinction. However, ungulates play an important role both in the ecosystem and in the economy. In general, species or breeds are considered endangered if their population does not exceed 1,000 individuals. In these cases conservation programmes should be initiated in order to maintain or even increase their number. This review deals with the possibilities and limitations of assisted reproductive technologies (ART) in the conservation of ecologically valuable wild, rare and indigenous ungulates. The methods discussed here are artificial insemination, cryopreservation of semen and embryos, embryo recovery and transfer, in vitro production of embryos, as well as micromanipulation techniques including sperm injection, assisted hatching and cloning. Some of these procedures are already being exploited in the breeding of farm ungulates, but more basic information about the reproductive patterns of wild, rare and indigenous animal species is needed before the routine use of ARTs. 相似文献
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Sato S Maeda C Hattori N Yagi S Tanaka S Shiota K 《The Journal of reproduction and development》2011,57(4):526-533
The Gsg2 (Haspin) gene encodes a serine/threonine protein kinase and is predominantly expressed in haploid germ cells. In proliferating somatic cells, Gsg2 is shown to be expressed weakly but plays an essential role in mitosis. Although the Gsg2 minimal promoter recognized by the spermatogenic cell-specific nuclear factor(s) has been found, to date, the molecular mechanism that differentially controls Gsg2 expression levels in germ and somatic cells remains to be sufficiently clarified. In this study, we analyzed the DNA methylation status of the upstream region containing the Gsg2 promoter. We found a tissue-dependent and differentially methylated region (T-DMR) upstream (-641 to -517) of the authentic promoter that is hypomethylated in germ cells but hypermethylated in other somatic tissues. Profiling of Gsg2 expression and DNA methylation status at the T-DMR in spermatogenic cells indicated that the hypomethylation of the T-DMR is maintained during spermatogenesis. Using the reporter assay, we also demonstrated that DNA methylation at the T-DMR of Gsg2 reduced the promoter activity by 60-80%, but did not fully suppress it. Therefore, the T-DMR functions as a modulator in a DNA methylation-dependent manner. In conclusion, Gsg2 is under epigenetic control. 相似文献