RAS/ERK和PI3K/Akt串线信号网络的敏感性分析研究

建立了一个包含RAS/ERK(extracellular signal-regulated kinase)和PI3K/Akt信号通路的生化反应网络,采用基于LHS(Latin Hypercube sampling)抽样的多参数敏感性分析方法计算了网络参数变化对于ERK活化的影响,分析了PI3K/Akt信号通路的引入对RAS/ERK信号通路敏感性分布的影响.研究结果表明,K14,K17,K21,Km23,V26,Km27,K29',K31,K33',K37',K42',Kcat43,K46' Km52,K52'等是ERK信号的敏感参数.与此前单独的ERK通路参数敏感性研究结果相比,发现了在Ras上游有敏感性参数存在,能够为抑制ERK,PI3K/Akt联合通路提供新的靶点寻找策略.     

The barrier to recombination between Escherichia coli and Salmonella typhimurium is disrupted in mismatch-repair mutants

The requirement for DNA sequence homology in generalized genetic recombination is greatly relaxed in bacterial mutL, mutS and mutH mutants deficient in mismatch repair. In such mutants, intergeneric recombination occurs efficiently between Escherichia coli and Salmonella typhimurium, which are approximately 20% divergent in DNA sequence. This finding has implications for speciation, for regulating recombination between diverged repeated sequences, and for hitherto difficult interspecies hybridizations.     

逆转录转座子LINE-1的活性调控及其在癌症中的作用

逆转座子长散布核元件-1(LINE-1)是一种跳跃基因,约占人类基因组的17%。LINE-1采用"复制-粘贴"的方式,以RNA为媒介,在基因组中进行转座易位。一般地,细胞中LINE-1的转座活性受到严格调控。而在肿瘤细胞中,LINE-1异常活化,以逆转座依赖或非依赖的方式,影响基因组的稳定性:前者可以改变靶基因表达、引起染色质重排或协助其他转座子(如SINEs等)进行转座;后者为表观遗传的方式,通过产生内源的调节性RNAs、形成LINE-1嵌合性转录、形成新的剪切位点或启动位点来改变临近基因的表达等。本文主要介绍LINE-1的组成及其转座活性调控,并讨论LINE-1转座在肿瘤中的功能,以期为LINE-1的深入研究、肿瘤的形成机制及治疗探索提供一些参考。     

Heritable formation of pancreatic beta-cell tumours in transgenic mice expressing recombinant insulin/simian virus 40 oncogenes

Following the transfer into fertilized mouse eggs of recombinant genes composed of the upstream region of the rat insulin II gene linked to sequences coding for the large-T antigen of simian virus 40, large-T antigen is detected exclusively in the beta-cells of the endocrine pancreas of transgenic mice. The alpha- and delta-cells normally found in the islets of Langerhans are rare and disordered. Well-vascularized beta-cell tumours arise in mice harbouring and inheriting these hybrid oncogenes.     

Identification of nuclear proteins encoded by viral and cellular myc oncogenes

The myelocytomatosis viruses are a family of replication-defective avian retroviruses that cause a variety of tumours in chickens and transform both fibroblasts and macrophages in culture through the activity of their oncogene v-myc. A closely related gene (c-myc) is found in vertebrate animals and is thought to be the progenitor of v-myc. Changes in the expression and perhaps the structure of c-myc have been implicated in the genesis of avian, murine and human tumours (for a review, see ref. 15). Elucidation of the mechanisms by which v-myc and c-myc might elicit tumorigenesis requires identification of the proteins encoded by these genes. To this end, we have expressed a portion of v-myc in a bacterial host and used the resulting protein to raise antisera that react with myc proteins. We report here that v-myc and c-myc encode closely related proteins with molecular weights (MWs) of approximately 58,000. Integration of retroviral DNA near or within c-myc in avian lymphomas apparently enhances expression of the gene. Here we have used cells from one such tumour to identify the protein encoded by c-myc and find that the coding domain for the gene is probably intact.     

Human insulin receptor and its relationship to the tyrosine kinase family of oncogenes

We have deduced the entire 1,370-amino-acid sequence of the human insulin receptor precursor from a single complementary DNA clone. The precursor starts with a 27-amino-acid signal sequence, followed by the receptor alpha-subunit, a precursor processing enzyme cleavage site, then the beta-subunit containing a single 23-amino-acid transmembrane sequence. There are sequence homologies to human epidermal growth factor receptor and the members of the src family of oncogene products.     

《河海月刊》的历史定位和社会影响

介绍由中国第一所水利高等院校——河海工程专门学校(现河海大学)1917年11月创办的《河海月刊》的创办背景、办刊宗旨及栏目设置等,考证其历史定位,探析其社会影响。考证及研究表明:《河海月刊》是中国创办最早的水利科技期刊;《河海月刊》对我国社会发展的最大贡献是造就了一支高水平的作者队伍;《河海月刊》发表的一些论著至今仍具科学价值;《河海月刊》秉承的"科学救国""实业救国"办刊理念,严谨求实、开拓创新的办刊精神得到了传承和弘扬。     

Induction of proliferation or transformation of neuroretina cells by the mil and myc viral oncogenes

The genome of the avian retrovirus MH2 contains, in addition to the v-myc oncogene shared with three other avian retroviruses (MC29, CMII and OK-10), a second cell-derived oncogene, v-mil (refs 1-3). Like the three other viruses, which contain only v-myc, MH2 induces mainly liver and kidney carcinomas in fowl and transforms fibroblasts and macrophages in vitro. However, MH2 and MC29 differ in their biological properties when assayed on cultures of chicken embryo neuroretina (NR) cells. Indeed, NR cells, which normally do not multiply in vitro, are induced to proliferate and become transformed upon infection with MH2, whereas infection with MC29 has no apparent effect on these cells. To analyse the functions of the two oncogenes of MH2, we isolated spontaneous and in vitro-constructed mutants of this virus and investigated their effects on NR cell multiplication and transformation. We report here that expression of v-mil is sufficient to induce NR cell proliferation, although it does not result in cell transformation. In addition, viruses expressing only the v-myc oncogene fail to induce any detectable change in NR cells. However, cooperation of the two oncogenes is required to achieve transformation of NR cells by MH2.     

Abrogation of IL-3 and IL-2 dependence by recombinant murine retroviruses expressing v-myc oncogenes

Several oncogenes are thought to cause transformation by affecting the signal transmission pathway of growth factors. One example is the induction of c-myc, the cellular homologue of the avian transforming oncogene v-myc, by platelet-derived growth factor (PDGF) among a set of genes associated with competence induction in fibroblasts. Another of the competence genes, r-fos, has been shown to be related to v-fos, the transforming gene of the FBJ sarcoma virus. In addition, PDGF induces c-fos, the cellular homologue of v-fos. The importance of c-myc induction is suggested by the observation that c-myc, under the control of a glucocorticoid regulator, can partially relieve the requirement of fibroblasts for PDGF. We have examined the effects of oncogenes on haematopoietic/lymphoid cell differentiation, immortalization and factor dependence for growth. Here we report the effects of recombinant murine retroviruses capable of expressing the avian v-myc. With interleukin-3 (IL-3)- or interleukin-2 (IL-2)-dependent cells, the viruses abrogated the requirement for growth factors and suppressed c-myc expression.     

土壤污染的植物修复技术:现状与前景

随着世界人口的快速增长(预计到2013年全球人口将达到70亿)和工业的迅猛发展，土壤这一人类赖以生存的必需资源正承受着越来越大的压力。因受到工业三废和农用化学品以及矿区的污染，有相当数量农田的土壤质量日趋下降。土壤污染的植物修复(即利用绿色植物来去除环境中的污染成分或将其转化为无毒的物质的过程)近年来受到世界各国的瞩目，并取得了很大的进展。本文综述了这一领域的近几年来的研究现状和发展趋势。     

轮轨滚动接触问题的研究现状

随着高速铁路的不断发展,轮轨滚动接触问题愈加突出,因此,倍受国内外学者的关注。轮轨滚动接触问题涉及的范围较广且较为复杂,并在一定程度上引发轮轨的疲劳损伤和波浪形磨损等破坏形式。基于理论分析和试验研究两个方面,着重对轮轨滚动接触的发展历史和研究现状进行了总结和分析,并综述了轮轨滚动接触疲劳和钢轨波浪形磨损的研究现状。从现有的研究成果来看,轮轨滚动接触理论已相对较为完善,而对于高速铁路轮轨滚动接触疲劳损伤的形成机理研究仍未形成系统的理论体系。     

Preparation of nano-compounded polyolefin materials through in situ polymerization technique: status quo and future prospects

Nano-compounding of polyolefins, an economical yet very effective route to high-performance polyolefin materials, has received considerable attention in recent years. Unlike most of the other polymers, polyolefins are chemically inert, which dictates that nano-compounding of polyolefins has to be conducted via in situ polymerization. In this review, a technological progress of the nano-compounding of polyolefins via in situ polymerization technique was summarized thoroughly, with emphasis laid on the current research status of polyolefin/montmorillonite (MMT) nanocomposites. A clear perspective for future researches on this specific family of materials was envisaged. Supported by National Natural Science Foundation of China (Grant No. 50373048) and State Key Development Program of Basic Research Program of Ministry of Science and Technology of China (Grant No. G2003CB615600)     

Smoluchowski方程的对称与显式解析解

文章研究一类积分-偏微分群体平衡方程的非完全不变群、群不变解和显式精确解及解的动力学行为和特征：首先,利用尺度变换群法探索群体平衡方程的不变群;其次,将积分-偏微分方程转化成纯偏微分方程, 采用经典李群分析方法探究纯偏微分方程的完全不变群, 应用改进的李群分析方法验证原群体平衡方程的非完全不变群;最后,给出了原群体平衡方程的非完全不变群、群不变解、约化积分-常微分方程及显式精确解, 研究了部分解蕴藏的动力学性态及特征。

     

精神外科的历史、现状与发展

 精神外科是功能性神经外科的重要分支,已有120余年的发展历史。随着临床精神病学、神经生化、神经影像学及微侵袭技术的发展,精神外科手术方式发生了重大改变。介绍了精神外科发展简史、国内外发展现状,并对未来发展进行了展望。