肝再生

肝脏在受到损害或切除之后,可以显示出强大的再生能力。肝再生这一现象早已被人们发现并研究。肝脏再生的启动因素有哪些,又是如何适时终止的?在肝再生过程中,哪些基因的表达发生了变化?哪些信号通路参与了肝再生过程?这些问题一直是研究者关注的焦点。本文将对肝再生研究的这些热点问题进行综述。     

Investigation of hrDNA targeting vector-mediated tumor-specific suicide gene therapy for hepatocellular carcinoma

Vectors pose most pivotal problem of gene therapy[1]. Because of the high transfection efficiency both in vitro and in vivo, the viral vector has been employed in 70% clinical trials of gene therapy (http://www.wiley.co.uk/ genmed/clinical). However, thei…     

Construction and anti-tumor effects of recombinant fowlpox virus expressing Newcastle disease virus hemagglutinin-neuramidinase gene

Hemagglutinin-neuramidinase (HN), a Newcastle disease virus-derived protein, not only mediates receptor recognition but also possesses neuraminidase (NA) activity, the ability to cleave a component of those receptors, N-acetylneuraminic acid (NAcneu, sialic acid). It is known that this protein in mammalian species, including human beings, has interesting anti-neoplastic as well as immune stimulating properties. To explore the use of the HN gene in cancer gene therapy, we constructed a recombi-nant fowlpox virus expressing the HN protein (vFV-HN) and compared the anti-tumor activity of the recombinant virus with that of wild-type fowlpox virus (FPV) in vivo and in vitro. Here we found that although B16 cells were somewhat resistant to the basal cytotoxic effect of wild-type fowlpox virus, infection with vFV-HN caused a pronounced cytotoxic effect and, the survival of tumor-bearing mice immunized with vFV-HN was significantly increased compared with the survival of mice immunized with the FPV alone. Furthermore, the immunization of mice with vFV-HN elicited a B16 tumor-specific cytotoxic T lymphocyte (CTL) response and clonal expansion of both CD4 and CD8 T cell populations in vivo. In addition, T cells from lymph nodes of mice vaccinated with vFV-HN secreted high levels of the Th1 cytokine IL-2 and IFN-γ, indicating that the regression of tumor cells is related to a Th1-type dominant immune response. These results demonstrate that vaccination with vFV-HN may be a potential strategy for cancer gene therapy.     

Rational design of glycerol dehydratase： Swapping the genes encoding the subunits of glycerol dehydratase to improve enzymatic properties

1,3-propanediol (1,3-PD) is an important material for chemical industry,and there has been always much interest in the production of 1,3-PD using all possible routes. The genes encoding glyc-erol dehydratase (GDHt) from Citrobacter freundii,Klebsiella pneumoniae and metagenome were cloned and expressed in E. coli. All glycerol dehy-dratases but the one from metagenome could be detected to show enzyme activities. In order to im-prove the enzymatic properties of GDHts,the genes encoding α and β-γ subunits were cloned,and the enzyme characteristics were evolved by rational de-sign based on their 3D structures which were con-structed by homology modeling. Six heteroenzymes were obtained by swapping the α subunit genes of these three different-source-derived GDHts. The pH,thermal stability and Vmax of some heteroenzymes were dramatically improved by 2―5 times compared with the wild one (GDHtKP). The GDHt cloned from metagenome,originally proved to be with no enzyme activity,was converted into active enzyme by swap-ping its subunits with other different GDHts. In addi-tion,the effect of subtle 3D structural changes on the properties of the enzyme was also observed.     

Gene flow from genetically modified herbicide-resistant rapeseed to cruciferous weeds

The sexual compatibility between genetically modified (GM) glyphosate-resistant rapeseed variety Q3 (Brassica napus L.) and 5 cruciferous weeds is studied through the observation of fluorescence microscopy and cross-fertility after manual pollination. The results indicated that Q3 (as male) was highly incompatible with Thlaspi arvense L., Capsella bursa?pastoris (L.) Medic, Cardamine hirsuta L. and Rorippa palustris (L.) Besser (as female). Fluorescence microscopic observation showed that growing of pollen tubes terminated on the stigma surface or at the upper 1/3 part of the style. However, B. juncea×Q3 was compatible, and the compatibility index was 1.65. Under the neighboring growth and natural pollination conditions, the rates of gene flow from Q3 to T. arvense, C. bursa-pastoris, C. hirsute and R. palustris were all 0, while it was 0.86% for B. juncea. These results indicate that there is difference in the rate of gene flow between GM rapeseed and cruciferous wild weeds, and frequency of gene flow is highly correlated with sexual compatibility.     

影响体细胞核移植重构胚发育的因素

目前已有多种动物被成功克隆,但存在着诸多未知因素,使体细胞核移植重构胚发育至囊胚阶段的比例过低,克隆动物存在早衰等异常现象.该文围绕这产生这些现象的根本原因、高度分化的体细胞核移入卵质后所发生的分子事件以及其影响因素如体细胞的来源和培养代数、细胞周期、核质相互作用、细胞核再程序化、线粒体等方面对体细胞核移植重构胚发育的影响等进行综述.     

水稻基因表达谱分析寡核苷酸芯片制备的研究

 首先有目的地搜集了50个水稻花序相关基因,进行了探针的设计、筛选及合成纯化,用点样仪以微阵列的形式将其点于醛基化的玻璃片上;将3个不同生长阶段的水稻花序材料的总RNA经荧光标记反转录后与寡核苷酸芯片进行杂交.用ScanArray3000对获得的表达谱进行扫描分析显示,芯片图像背景均匀,信号清晰.用ImaGene4.0软件对表达谱分析表明,候选基因在水稻花序3个不同发育阶段的材料中,表达水平有显著差异.为进一步进行水稻寡核苷酸芯片的制备及应用奠定了基础.     

基因科技面临的人权困境及出路

基因科技是人权课题的新领域。基因科技的发展面临难以抉择的人权困境。该文从平等权、生命健康权、隐私权、性权利和生育权、人权的类本质等方面分析基因科技涉及的人权问题,从科技人员自律、加强社会基因科技认知和风险防范意识、强化政府的责任意识、坚持用马克思主义人权观指导基因科技研究等方面探索了摆脱此种人权困境的出路。     

血吸虫膜相关抗原基因的克隆

目的:筛选日本血吸虫(Schistosoma japonicum,S.japonicum)新的疫苗候选抗原基因.方法:以S.japonicum成虫DNA为模板,PCR扩增相关基因,然后将其克隆XpBS-T载体,通过菌落PCR对产物进行检测,对阳性克隆子测序,与GeneBank中的已知相关序列进行比对分析.结果:菌落PCR获得一条与PCR产物一致的DNA片段,序列测定结果表明PCR产物与S.japonicum 22.6 kDa抗原分子核苷酸序列具有高度同源性.其目的基因大小636 bp,具有一个189 bp的ORF,能编码63个氨基酸.ORF不是全长的阅读框,只获得部分编码区.表达产物可含有一个包含9个氨基酸残基的潜在螺旋跨膜片段(25～33位)和一个酪氨酸激酶磷酸化位点(38～39位).讨论:成功克隆出一个与S.japonicum 22.6kDa抗原编码基因有高度同源性的基因.预测该基因为膜相关蛋白基因,可编码血吸虫体表膜相关蛋白.在生理机能上,该膜相关蛋白可能是信号传递分子.