Sequential Gene Silencing Using Wavelength‐Selective Caged Morpholino Oligonucleotides

Spectrally differentiated caged morpholino oligonucleotides (cMOs) and wavelength‐selective illumination have been used to sequentially inactivate organismal gene function. The efficacy of these reverse‐genetic chemical probes has been demonstrated in zebrafish embryos, and these reagents have been employed to examine the mechanisms of mesoderm patterning.     

显式方法精确模拟形状记忆合金循环荷载下的变形行为

本文提出全新的有限弹塑性J2流方程,用来显式、精确地模拟SMAs（形状记忆合金）材料在循环加载-卸载条件下从塑性逐渐转变为伪弹性的变形行为．首先,改进流动法,使得本构方程耦合屈服中心的移动和屈服面的增大,并改进背应力演化方程,使模型可以产生强烈的包辛格效应,从理论上具备模拟SMAs独特变形行为的能力;其次,构造全过程下的统一硬化函数显式表达式,代入本构方程后能得到符合要求的形函数;再次,利用选定的数据点构造统一光滑的上屈服函数,再利用上下屈服应力之间的一种线性关系,推导得到下屈服阶段的形函数;最后,只需要给定一个参数就可以得到单个循环结果,利用拉格朗日插值方法构建参数随循环次数变化的函数,就可以模拟任意循环荷载下的变形行为．通过模型结果和实验数据对比证明新方法的有效性．     

Antihyperglycaemic mechanisms of an aceteoside polymer from rose flowers and a polysaccharide–protein complex from abalone mushroom

Oral administration of an aceteoside polymer from rose Rosa rugosa (P_1-b) and a polysaccharide–peptide complex from abalone mushroom Pleurotus abalonus (LB-1b), both with antioxidant activity, produced antihyperglycaemic effects in alloxan-induced diabetic mice. The expression of insulin, superoxide dismutase and pancreas duodenum homeobox factor-1 essential for pancreatic islet function as estimated by real-time PCR was augmented. The reactive oxygen species-scavenging ability of the rose constituent was notably stronger than the mushroom constituent. Thus, the two biomolecules protected the pancreas from oxidative stress, elevated pancreatic insulin expression and lowered circulating glucose level.     

Design of Photocaged Puromycin for Nascent Polypeptide Release and Spatiotemporal Monitoring of Translation

The antibiotic puromycin, which inhibits protein translation, is used in a broad range of biochemical applications. The synthesis, characterization, and biological applications of NVOC‐puromycin, a photocaged derivative that is activated by UV illumination, are presented. The caged compound had no effect either on prokaryotic or eukaryotic translation or on the viability of HEK 293 cells. Furthermore, no significant release of ribosome‐bound polypeptide chains was detected in vitro. Upon illumination, cytotoxic activity, in vitro translation inhibition, and polypeptide release triggered by the uncaging of NVOC‐puromycin were equivalent to those of the commercial compound. The quantum yield of photolysis was determined to be 1.1±0.2 % and the NVOC‐puromycin was applied to the detection of newly translated proteins with remarkable spatiotemporal resolution by using two‐photon laser excitation, puromycin immunohistochemistry, and imaging in rat hippocampal neurons.     

Recombinant Expression and Phenotypic Screening of a Bioactive Cyclotide Against α‐Synuclein‐Induced Cytotoxicity in Baker′s Yeast

We report for the first time the recombinant expression of fully folded bioactive cyclotides inside live yeast cells by using intracellular protein trans‐splicing in combination with a highly efficient split‐intein. This approach was successfully used to produce the naturally occurring cyclotide MCoTI‐I and the engineered bioactive cyclotide MCoCP4. Cyclotide MCoCP4 was shown to reduce the toxicity of human α‐synuclein in live yeast cells. Cyclotide MCoCP4 was selected by phenotypic screening from cells transformed with a mixture of plasmids encoding MCoCP4 and inactive cyclotide MCoTI‐I in a ratio of 1:5×10⁴. This demonstrates the potential for using yeast to perform phenotypic screening of genetically encoded cyclotide‐based libraries in eukaryotic cells.     

单点子域积分与差分

通过稳定性分析、显式与隐式积分，表明了单点子域积分相对于差分法的优越性．     

碱基序列标记法结合焦磷酸测序测定不同来源基因表达量

建立了一种将序列标记反转录聚合酶链反应(PCR)与焦磷酸测序技术结合的相对基因表达量测定法(简称"SRPP").先用来源特异性引物对不同来源的同一基因通过反转录标记上特异性标签,PCR后用焦磷酸测序法对扩增产物进行序列解码,使得测序结果中的序列代表基因的来源,峰高代表基因在不同来源中的相对表达量.用实时荧光定量PCR法对本方法的准确性进行了验证,结果表明,SRPP可以同时准确测定同一基因在3个不同来源中的表达量,并实际测定了Egr1基因在糖尿病、肥胖和正常小鼠肝中的表达量差异.     

Immune Responses to a Dicistronic Plasmid Expressing HBsAg of Hepatitis B Virus and Interferon-γ

DNA vaccines encoding a viral protein have been shown to induce antiviral immune responses and provide protection against subsequent viral challenge.The present article deals with the efficacy of a DNA vaccine greatly improved by the simultaneous expression of HBsAg and interferon-γ gene.We constructed a dual expression vector pHIN encoding the HBsAg of Hepatitis B virus and murine IFN-γ which are connected with Internal Ribosome Entry Site(IRES).Mice immunized with this dual expression DNA vaccine exhibited the enhancement of cellular immune response and increased the production of anti-HBV surface antibody,compared with the mice of single gene expression control.Taken together,these results demonstrate that the application of a cytokine gene in a DNA vaccine formulation as an adjuvant can improve its immunigenicity.