紫外分光光度法测定牛黄中胆酸的研究

本文研究了用紫外分光光度法测定牛黄中胆酸的实验条件和方法。     

两种人粒酶B嵌合基因的表达及对肿瘤细胞的杀伤作用

通过重组PCR构建了抗HER2单链抗体基因、绿脓杆菌外毒素 (PE)转位肽序列和活性型粒酶B(GrBa)基因相融合的sFv2 3e PEⅡ GrBa基因 ,以及N端包含PE部分转位肽序列的PEⅡ GrBa基因 .将这 2种粒酶B嵌合蛋白基因瞬时转染或稳定转染HeLa细胞及SKBR 3细胞 .通过间接免疫荧光、细胞计数、MTT、ELISA等方法 ,观察到细胞浆中表达的PEⅡ GrBa蛋白直接杀伤其表达细胞 ;而sFv2 3e PEⅡ GrBa表达后被分泌至细胞外 ,对产生它的细胞没有杀伤性 ,但能够特异识别并杀伤HER2阳性肿瘤细胞 .结果表明 ,抗肿瘤表面抗原的抗体能够介导靶向识别 ,转位结构域可以辅助效应分子活化、转位至细胞液并杀伤细胞 ,为肿瘤的靶向治疗提供了新的策略 .     

重组人凋亡诱导因子基因的构建、表达及其对HeLa细胞的促凋亡作用

凋亡诱导因子（apoptosis-inducing factor, AIF）定位于细胞的线粒体膜间隙.当凋亡信号刺激时,AIF分子从线粒体释放到胞浆,然后转位到细胞核内,引起染色体核周边凝集和DNA呈大片段断裂（～50 kb）.用RT-PCR法分段克隆得到人全长AIF基因,经改造截去其N端线粒体定位信号编码序列,代之以不同长度的绿脓杆菌外毒素(PE)转膜结构域序列.把这些重组基因克隆入pIRES2-EGFP真核表达载体,脂质体法转染HeLa细胞,通过荧光显微镜观察、共聚焦显微镜观察、电镜观察等方法检测了多种重组人AIF基因的表达及其对细胞生长的影响.证明了重组人AIF基因的表达可引起HeLa细胞死亡,为肿瘤的杀伤提供了新的策略.     

Construction of a trivalent candidate vaccine against Shigella species with DNA recombination

In this work asd gene of Shigella flexneri 2a strain T32 was replaced by Vibrio cholerae toxin B subunit (ctxB) gene with DNA recombination in vivo and in vitro. The resulting derivative of T32, designed as FWL01, could stably express CtxB, but its growth in LB medium depended on the presence of diaminopimelic acid (DAP). Then form I plasmid of Shigella sonnei strain S7 was labeled with strain T32 asd gene and mobilized into FWL01. Thus a trivalent candidate oral vaccine strain, designed as FSW01, was constructed. In this candidate strain, a balanced-lethal system was constituted between the host strain and the form I plasmid expressing S, sonnei O antigen. Therefore the candidate strain can express stably not only its own O antigen but also CtxB and O antigen of S. sonnei in the absence of any antibiotic. Experiments showed that FSW01 did not invade HeLa cells or cause keratoconjunctivitis in guinea pigs. However, rabbits immunized FSW01 can elicit significant immune responses. In mice and rhesus monkey     

细菌作为肿瘤基因治疗载体的研究进展

营养缺陷型细菌能够侵袭肿瘤细胞并外源基因的特性提示我们可以将其设计成新型的肿瘤基因治疗载体。本文综述了细菌作了肿瘤基因治疗载体的历史与现状、机制以及存在的问题。     

转化生长因子α反义RNA对人脑胶质瘤细胞系BT_(325)的生长抑制和诱导分化作用

转化生长因子α(TGFα)以自泌和旁泌的形式与肿瘤细胞表面表皮生长因子受体(EGFR)结合,在肿瘤的发生发展中起着重要作用。阻断这种自泌和旁泌体系可能对肿瘤细胞产生影响。为此我们构建了含TGFα反义基因的逆转录病毒重组载体并将其导入人脑胶质瘤细胞系BT_(325)中,成功地表达了TGFα反义RNA。在反义RNA作用下,肿瘤细胞发生了显著变化,结果如下:     

华北石质山区油松林对降水再分配过程的影响

森林通过降水再分配过程影响着流域的水量平衡和物质循环。根据2005-2008年汛期华北石质山区主要造林树种油松林的林外降雨、穿透降雨、树干径流定位观测数据,探讨了人工油松林对降雨再分配过程的影响。结果表明,测定期间32场次降雨过程中油松林穿透雨量、树干径流量和林冠截留量平均值分别为8.67,0.11,1.07mm;透过率,树干径流率和林冠截留率分别为82.18%(57.74%-87.55%),1.07%(0.22%-2.07%),16.75%(11.01%-42.07%)。油松林冠层穿透降雨量、树干径流量和林冠截留量均与林外降雨量呈明显的线性关系(R2=0.995,R2=0.907,R2=0.855),根据回归方程,当林外降雨量大于0.3mm时,可发生穿透降雨,当林外降雨量大于3.51mm时,可发生树干径流;林冠截留率与林外降雨呈双曲线衰减趋势,回归方程为y=12.091+55.537/(x+0.426)(N=32,R2=0.685)。典型次降雨再分配过程表明,林冠不仅在量上对降雨进行再分配,还在时程上进行了再分配。     

细菌作为肿瘤基因治疗载体的研究进展

营养缺陷型细菌能够侵袭肿瘤细胞并呈递外源基因的特性提示我们可以将其设计成新型的肿瘤基因治疗载体。本文综述了细菌作为肿瘤基因治疗载体的历史与现状、机制以及存在的问题。     

Construction of a trivalent candidate vaccine against Shigella species with DNA recombination

In this work asd gene of Shigella flexneri 2a strain T32 was replaced by Vibrio cholerae toxin B subunit (ctxB) gene with DNA recombination in vivo and in vitro. The resulting derivative of T32, designed as FWL01, could stably express CtxB, but its growth in LB medium depended on the presence of diaminopimelic acid (DAP). Then form I plasmid of Shigella sonnei strain S7 was labeled with strain T32 asd gene and mobilized into FWL01. Thus a trivalent candidate oral vaccine strain, designed as FSW01, was constructed. In this candidate strain, a balanced-lethal system was constituted between the host strain and the form I plasmid expressing S. sonnei O antigen. Therefore the candidate strain can express stably not only its own O antigen but also CtxB and O antigen of S. sonnei in the absence of any antibiotic. Experiments showed that FSW01 did not invade HeLa cells or cause keratoconjunctivitis in guinea pigs. However, rabbits immunized FSW01 can elicit significant immune responses. In mice and rhesus monkey models, vaccinated animals were protected against the challenges of wild S. flexneri 2a strain 2457T and S. sonnei strain S9.     

自由基与细胞凋亡

细胞凋亡是指细胞在生理和病理情况下的一种死亡模式,广泛涉及到肿瘤、衰老和退行性病变等一系列疾病．最近有实验表明自由基与细胞凋亡有密切的关系．凋亡细胞内活性氧自由基（ROS）生成增加,同时消除ROS的能力下降.大多数凋亡障碍的细胞表现出ROS分子大量减少,若调节细胞内ROS含量,死亡率能随之改变;离子辐射能通过经自由基引起细胞的凋亡,培养细胞在无血清或撤除生长因子后发生的死亡也大多与细胞内自由基代谢酶如过氧化氢酶等的活性变化有关.提示自由基是参与调节细胞凋亡的重要因素之一.