Fragile X mental retardation protein interacts with TDG

Fragile X syndrome is the most common form of inherited mental retardation disease, resulting from absent of expression of its disease geneFMR1. To study the function of the fragile X mental retardation protein (FMRP) through protein/protein interaction, a mouse embryo cDNA library was screened by the yeast two-hybrid system. A clone was found to interact specifically with FMRP. The cDNA of this clone (Genbank accession number af 102875) encoded a protein highly homologous to human G/T mismatch-specific DNA thymine glycosylase (hTDG). Interactions between various alternatively spliced FMRP isoforms and a series of mTDG deletion proteins were further studied in the yeast two-hybrid system and their interaction amino acid regions were determined. Interaction between FMRP and TDG existed inside exon 13 of FMRP (amino acid residue 397–425) and around amino acid residue 122–346 of TDG. These results will be helpful to the study of the biological role of FMRP.     

CH_3F与O(~3P)反应机理的量子化学研究

用量子化学从头算MP2/6-311G(d,p)方法研究了CH3F与O(3P)反应的反应机理.在QCISD(T)/6-311G(d,p)水平上精确计算了各反应物种的能量.结果表明,标题反应共存在4类反应5个反应通道,分别为抽提氢反应、抽提氟反应、消氟化氢反应和消氢反应,抽提氢反应为主反应通道.     

关于贝尔的翻译过程模式

贝尔以心理语言学和人工智能的研究成果为基础 ,构建了翻译过程的心理模式 .本文拟对其加以述介和评论 .     

实验室级局域网的组建技术及其实践

本文讨论了局域网的主要组建技术,并从实际出发,组建了拓扑结构物理上为星型,逻辑上为总线型的双绞线以太网。采用WindowsNT的单域模型实现实验室级局域网所要求的网络功能,并进一步探讨了局域网的发展及相关问题。     

瑞典科技创新与评估对我国的启示

本文简要介绍了瑞典科技创新体系的重要构成,从科技管理的视角对瑞典“科技创新”与“科技评估”的做法、特点及突出经验进行了阐述和分析,进而提出有关思考与建议,以期能够对我国的科技创新与科技评估工作有所启发。     

HIV-TATm-Survivin(T34A)高表达大肠杆菌BL21(DE3)菌株的自适应进化筛选及其特性

表达蛋白HIV-TATm-Survivin(T34A)的重组大肠杆菌BL21(DE3)在长时间保存后其表达水平明显下降,发酵罐放大难以顺利进行。利用该蛋白的本底表达对宿主菌产生的生长压力进行了实验室自适应进化工作,得到携带相同质粒但表达水平呈两极分化的两类菌株HTS1和HTS2。摇瓶培养时,HTS1菌株生长较迅速,但重组蛋白几乎无表达;HTS2生长较缓慢,却可以高效积累重组蛋白。因此HTS1菌株的出现,可能是原始菌株长时间保存后蛋白表达能力下降的原因之一。另外,HTS2菌株应用上的优势,外源添加高达300 mmol/L的乙酸钠对HIV-TATm-Survivin(T34A)的表达水平没有较明显负的影响,4 L和30 L发酵罐表达验证了摇瓶培养的结果。     

中等强度体力活动与T2DM风险——系统综述

目的系统评价中等强度体力活动与T2DM之间的关系。方法检索EMBASE和Medline(截止2010年7月)相关文献,并追踪参考文献目录。剔除未将中等强度体力活动与剧烈活动(>6MET)区分开的文献。采用随机效应模型计算总相对风险(RR)。结果对10个队列研究进行分析,共有301,221名参与者,其中9,367例发病。其中5例专门研究了步行的作用。参与规律的中等强度体力活动与静坐少动者相比,T2DM的总RR为0.69(95%CI0.58～0.83)。同样,规律步行(尤其是快走≥2.5h/周)与基本不步行者相比RR为0.70(95%CI0.58～0.84)。调整了BMI后相关性仍旧有显著性。在美国和欧洲,男性与女性中都观察到类似的相关性。结论 MPA可使T2DM发病风险降低约30%,其相关性部分独立于BMI,提示MPA降低T2DM风险的作用也可发生在未出现体重下降的人群。快走被认为是预防糖尿病的最佳手段,但步行的最佳持续时间和速度及最佳组合方式还需进一步研究。预防T2DM要加大力度宣传MPA的益处,鼓励更多的人参与进来。     

Expression of the mutant gene for L-gulono-γ-lactone oxidase in scurvy-prone rats

A mutant strain of Wistar rats with L-gulono-TQ357738740104T/xxlarge947.gif" alt="gamma" align="MIDDLE" border="0">-lactone oxidase deficiency has recently been established. To investigate this deficiency by DNA and RNA blot hybridization analyses, a fragment of a previously cloned cDNA encoding rat L-gulono-TQ357738740104T/xxlarge947.gif" alt="gamma" align="MIDDLE" border="0">-lactone oxidase was used as a probe. When genomic DNA of the mutant rat was digested with several restriction enzymes, the probe hybridized to fragments of the same sizes as those produced from DNA of normal rats. Poly(A)⁺RNA from the liver of the mutant rat was found to contain an L-gulono-TQ357738740104T/xxlarge947.gif" alt="gamma" align="MIDDLE" border="0">-lactone oxidase-specific mRNA of a normal size at a comparable level to that of normal rats. An in vitro translation experiment revealed that the mRNA programmed the synthesis of an enzyme protein which had the same molecular weight as that of the translational product of the normal mRNA, although the amount synthesized was markedly reduced as compared with that synthesized with the normal mRNA. In accordance with this observation, a very low but definite degree of L-gulono-TQ357738740104T/xxlarge947.gif" alt="gamma" align="MIDDLE" border="0">-lactone oxidase activity was detected in the microsomes of the mutant rat by a newly developed, highly sensitive method.Acknowledgments. The authors thank Dr Susumu Makino, Shionogi Research Laboratories, Shionogi & Co., Ltd, Japan, for his kind donation of normal (ODS- +/+) and ODS (ODS-od/od) rats. This work was supported in part by Grant-in-Aid (59570103) for Scientific Research from the Ministry of Education, Science and Culture of Japan.     

微波复数介电常数虚部ε″测量方法的研究

通过对现有介电常数实验方法的改进,并结合单片机对实验进行自动控制及数据的采集、处理、解决了反射式速调管微波源输出功率、频率不稳及现有实验测量仪器分辨率低等因素对测量微波复数介电常数虚部ε″的影响,提高了ε″的测量精度。     

Effects of diapause and host species on some morphometric characters inTrichogramma (Hym.: Trichogrammatidae)

Adult morphology ofTrichogramma is modified by environmental conditions during the preimaginal development. For instance, the low temperatures inducing diapause cause a decrease of the ratio length of longest seta on male flagellum/width of flagellum inT. evanescens. The species of the host also influences numerous body ratios. So, in females, the development of tibiae with regard to wings is more important withScotia ipsilon than withGalleria mellonella. These results confirm the necessity of performing comparative morphological studies on individuals reared in the same conditions.