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991.
Janet H. Parham Marie A. Iannone Laurie K. Overton Jeff T. Hutchins 《Cytotechnology》1998,28(1-3):147-155
The goals of this study were to identify mammalian cell lines which could be efficiently transiently-transfected and scaled-up
for protein production. The transfection efficiencies of eight cell lines (NSO, NSO-TAg, CV-1, COS-7, CHO, CHO-TAg, HEK 293,
and 293-EBNA) were measured using electroporation for DNA delivery and green fluorescent protein (Evans, 1996) as the reporter
gene. In addition, we have evaluated the effects of stable expression of viral proteins, cell cycle manipulation, and butyrate
post-treatment in small scale experiments. The cell lines varied widely in their GFP transfection efficiencies. Stable expression
of simian virus 40 large T-antigen or Epstein Barr nuclear antigen failed to significantly increase transfection efficiency
above that seen in the parental lines. Aphidicolin (a DNA polymerase inhibitor), which blocked cells from S or G2/M, brought
about an increase in transfection efficiency in two cell lines. The primary effect of butyrate (a histone deacetylase inhibitor)
post-treatment was an increased intensity of the fluorescent signal of green fluorescent protein, as measured by flow cytometry
(1.0 to 4.2-fold, depending on the cell line). The combined use of aphidicolin pretreatment followed by butyrate treatment
post- electroporation yielded increases in fluorescence intensities ranging from 0.9 to 6.8-fold. Based on their high transfection
efficiencies in small scale experiments, rapid growth, and ability to grow in suspension culture, CHO, CHO-TAg, and 293-EBNA
were selected to assess the feasibility of using flow electroporation for large-scale transfections. Using secreted placental
alkaline phosphatase as a reporter, 293-EBNA cells produced the highest protein levels in both the presence and absence of
butyrate. These data indicate that flow electroporation provides an efficient method of DNA delivery into large numbers of
cells for mammalian protein production.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
992.
Calcium-alginate beads were found to bind a variety of enzymes in a nonspecific fashion. However, alpha amylases from porcine pancreas, Bacillus subtilis (BAN 240L) and wheat germ bound at a significant level and B. subtilis and wheat germ amylases could be eluted with 1M maltose. The wheat germ alpha amylase could be purified 45 fold with 70% recovery. The SDS - PAGE pattern showed significant purification by this single step strategy. 相似文献
993.
994.
Bacterial DNA as immune cell activator 总被引:12,自引:0,他引:12
Pattern recognition receptors of the innate and adaptive immune systems apparently recognize unmethylated CpG motifs of bacterial DNA. Cells of the innate immune system are activated directly by CpG motifs, and the resulting response dictates a Th1 bias to the developing adaptive immune response. Interestingly, antigen receptor occupancy of cells of the adaptive immune system augments their responsiveness to CpG motifs, suggesting that co-stimulatory mechanisms are operative. 相似文献
995.
996.
新型戊型肝炎诊断试剂盒的研制及其应用 总被引:5,自引:1,他引:4
用HEVORF3合成肽及ORF2重组抗原研制成新型HEVEIA诊断试剂盒。与GenlabsHEVEIA检测比较,灵敏度和特异性均达100%(60/60)。三批试剂精密性测定均<10%。该试剂盒置4℃8个月或37℃4d保持稳定。检测不同肝炎患者HEV抗体,发现急性非甲非乙非丙肝炎中有63.2%,甲肝有13.4%,乙肝有8.3%,丙肝有6.6%,正常人群为2.9%。所研制的戊型肝炎诊断试剂盒,灵敏度高,特异性强,精密性好,稳定性合格。适用于戊型肝炎诊断及戊肝病毒感染的流行病学调查 相似文献
997.
庚型肝炎病毒NS5区蛋白鼠单克隆抗体的制备 总被引:2,自引:0,他引:2
庚型病毒性肝炎是近年来世界上才确认的一种新型肝炎[1~3]。庚型肝炎病毒(HGV)呈世界性分布,经血液传播为主,也可母婴传播。HGV容易形成持续性感染,类似HIV和HCV。据粗略估计,我国大约有100万~1000万HGV携带者。因此,HGV已成为继乙... 相似文献
998.
吴明 《上海生物医学工程》1998,19(1):55-58
本文描述神经干复合动作电位实验的软件设计及其主要特点,友好的人机界面和简便的波形处理,并给出了实际实验结果,由于软件设计在智能化仪器中的重要作用,所以应加以仔细考虑。 相似文献
999.
在肠毒素大肠杆菌(ETEC)的已知定居因子中,CS3是临床分离株中最常见的抗原之一。为了研究CS3纤毛装配的基本元件,绘制了CS3亚基结构基因和辅助蛋白编码区的限制酶谱。通过亚克隆的亚基基因和不同辅助蛋白基因之间的互补性表达结果,确定了CS3纤毛装配所需要的辅助蛋白的DNA功能片段。微细胞分析结果显示,CS3基因的有效表达和纤毛装配至少需要6条蛋白多肽,分子量分别为(×10~3)15、17、24、27、48和90。除了15×10~3/17×10~3的蛋白多肽为CS3亚基外,其余的蛋白多肽参与CS3亚基的转运及纤毛的装配。根据以上结果初步确定了上述相关基因的相对位置。 相似文献
1000.
A significant component of polarization in budding yeast involves the regulated restructuring of the actin cytoskeleton in response to defined cellular signals. Recent evidence suggests that such cytoskeletal organization arises through the action of large protein complexes that form in response to signals from small GTP-binding proteins, such as Cdc42, Rho, and Ras. These actin-organizing complexes may be fairly diverse, but generally consist of one or more central scaffold proteins, such as those of the formin class, that bind to signaling molecules and recruit actin-binding proteins to bring about desired polarizing events. 相似文献