The first cleavage of the mouse zygote predicts the blastocyst axis

One of the unanswered questions in mammalian development is how the embryonic-abembryonic axis of the blastocyst is first established. It is possible that the first cleavage division contributes to this process, because in most mouse embryos the progeny of one two-cell blastomere primarily populate the embryonic part of the blastocyst and the progeny of its sister populate the abembryonic part. However, it is not known whether the embryonic-abembryonic axis is set up by the first cleavage itself, by polarity in the oocyte that then sets the first cleavage plane with respect to the animal pole, or indeed whether it can be divorced entirely from the first cleavage and established in relation to the animal pole. Here we test the importance of the orientation of the first cleavage by imposing an elongated shape on the zygote so that the division no longer passes close to the animal pole, marked by the second polar body. Non-invasive lineage tracing shows that even when the first cleavage occurs along the short axis imposed by this experimental treatment, the progeny of the resulting two-cell blastomeres tend to populate the respective embryonic and abembryonic parts of the blastocyst. Thus, the first cleavage contributes to breaking the symmetry of the embryo, generating blastomeres with different developmental characteristics.     

In vitro production of functional sperm in cultured neonatal mouse testes

Spermatogenesis is one of the most complex and longest processes of sequential cell proliferation and differentiation in the body, taking more than a month from spermatogonial stem cells, through meiosis, to sperm formation. The whole process, therefore, has never been reproduced in vitro in mammals, nor in any other species with a very few exceptions in some particular types of fish. Here we show that neonatal mouse testes which contain only gonocytes or primitive spermatogonia as germ cells can produce spermatids and sperm in vitro with serum-free culture media. Spermatogenesis was maintained over 2?months in tissue fragments positioned at the gas-liquid interphase. The obtained spermatids and sperm resulted in healthy and reproductively competent offspring through microinsemination. In addition, neonatal testis tissues were cryopreserved and, after thawing, showed complete spermatogenesis in vitro. Our organ culture method could be applicable through further refinements to a variety of mammalian species, which will serve as a platform for future clinical application as well as mechanistic understanding of spermatogenesis.     

IGF-Ⅱ and IGFBP-1 reversely regulate blastocyst implantation in mouse

Insulin-like growth factor (IGF)-Ⅱ and IGF binding protein (IGFBP)-1, members of IGF family, are important in the cyclic development of endometrium and the blastocyst implantation. In the present study, the indirect immunofluorescence showed that IGF-Ⅱ and IGFBP-1 were specifically expressed at the maternal-fetal interface. In a co-culture system, IGF-Ⅱ significantly enhanced the attachment and outgrowth of the blastocyst on monolayer of uterine epithelial cells, while IGFBP-1 did not affect the blastocyst attachment, but markedly inhibited the blastocyst outgrowth. The results of zymography showed that IGF-Ⅱ enhanced the activities of MMP-2 and MMP-9, while IGFBP-1 did not affect the activities of MMP-2 and MMP-9. In conclusion, the equilibrium between the invasion of trophoblast and the inhibition of deciduas may be regulated by the interaction between the IGF-Ⅱ-expressing invading cytotrophoblast and maternal deciduas-derived IGFBP-1.     

In vitro differentiation of human adipose-derived mesenchymal stem cells into endothelial-like cells

The neovascularization of ischemic tissue is a crucial initial step for the functional rehabilitation and wound healing. However, there is lack of a potential source of cells for the foundation of a vascular network. The re- cent studies indicate that hum…     

纳米氧化硅的体外细胞毒性

采用红细胞溶血实验、MTT法、形态学和测定培养液中乳酸脱氢酶(LDH)含量比较纳米S iOx及微米S iO2对红细胞和RAW264.7细胞的毒性作用;测定丙二醛(MDA)、过氧化氢(H2O2)、羟自由基(.OH)、超氧阴离子自由基(O2.-)、一氧化氮(NO)等氧化应激指标,探讨其毒作用机制.研究结果表明:纳米S iOx与微米S iO2在一定粒子浓度范围内致红细胞溶血率及生成MDA的量随浓度增加逐渐升高,呈剂量-反应关系;RAW264.7细胞的半数抑制浓度(IC50)分别为11.60,38.12mg/cm2;染毒细胞体积明显增大,呈气球样变;纳米S iOx及微米S iO2在0.036~0.571mg/cm2浓度范围内,可引起培养液中LDH活性显著升高,呈时间-效应关系,相同浓度纳米S iOx致培养液中LDH含量高于微米S iO2;染毒细胞内MDA,H2O2,.OH,O2.-,NO水平显著升高.结果提示相同浓度纳米S iOx的毒性作用较微米S iO2强,氧化应激在细胞毒性中起一定作用.     

苞叶杜鹃离体培养及种质试管保存体系的建立

以苞叶杜鹃新生嫩芽为外植体,应用均匀设计法筛选其最适合的培养基,建立了苞叶杜鹃的离体培养和种质试管保存体系。结果表明：适合苞叶杜鹃基部直接再生芽苗的诱导培养基为DR+TDZ(1.80 mg/L)+IBA(005 mg/L),此条件下芽苗分化率为100%;生根培养基为MS(改良)+IBA(0.08 mg/L)+NAA(0.02 mg/L)+KT(0.15 mg/L),这一条件下芽苗生根率达99%以上;试管保存培养基为1/7MS+B9(1.30 mg/L)+根皮苷(2.80 mg/L),常温条件下保存时间超过35个月。以苞叶杜鹃再生植株茎节为材料进行快繁的结果表明,在35 d的培养周期内,平均增殖倍数超过55倍。     

DSS的实现与研究

在ＭＩＳ应用和专项ＤＳＳ开发的基础上，从决策支持系统通用化的角度，利用结构化方法和ＩＤＳＳ、ＧＤＳＳ等最新研究成果，提出了设计ＤＳＳ的一种思路和方法。     

温室黄瓜环境管理智能决策支持系统初探

以黄瓜温室栽培和环境控制试验中所建立的一系列作物模型、环境模型和经济模型为基础,以Delphi6．0为软件开发环境,建立温室黄瓜环境优化调控管理的智能决策支持系统．该系统以兼顾作物生长和经济效益为目标,能够根据各种气象参数,给出温室环境实时控制最佳环境参数．     

药品采购决策支持系统数据仓库模型的研究

通过对决策支持系统和数据仓库的研究，提出了基于数据仓库的药品采购决策支持系统，并针对医院药品领域数据的自身特点设计了相应的数据仓库的模型。主要研究了数据仓库中的数据组织和设计数据仓库模型的关键技术，并简要给出了相应的设计方案。