抗高血压肽在大肠杆菌中表达的研究

本研究根据已经公开发表的具有降血压作用的来源于酪蛋白的一段多肽氨基酸序列CEI12,人工合成了一段双链DNA分子,经酶切后与表达载体pQE16连接,转化进入到大肠杆菌E.ColiJM109和E.ColiDH5嶂校又猩秆〕鲅粜灾刈榭寺。⒔杏盏急泶铮璖DS-PAGE电泳分析和westernblotting蛋白质印迹检测表明,该抗高血压小肽CEI12(与DHFR融合后)在E.ColiJM109中得到了成功表达。     

中国大鲵可溶性蛋白制备及SDS-PAGE电泳分析

采用超声法制备大鲵可溶性蛋白质;从提取温度、时间、液料比方面确定适宜的工艺参数,并对所得可溶性蛋白的分子量进行研究。均匀设计实验结果表明:在提取温度为45℃、提取时间为30min、液料比为10∶1时,大鲵可溶性蛋白溶出量最多,达63.57mg/g。SDS-PAGE电泳分析可溶性蛋白的组成表明,大鲵可溶性蛋白亚基分布广泛,分子量低,易于消化吸收,为优质的营养蛋白。     

The Internal Structure of the Velvet Worm Projectile Slime: A Small-Angle Scattering Study

For prey capture and defense, velvet worms eject an adhesive slime which has been established as a model system for recyclable complex liquids. Triggered by mechanical agitation, the liquid bio-adhesive rapidly transitions into solid fibers. In order to understand this mechanoresponsive behavior, here, the nanostructural organization of slime components are studied using small-angle scattering with neutrons and X-rays. The scattering intensities are successfully described with a three-component model accounting for proteins of two dominant molecular weight fractions and nanoscale globules. In contrast to the previous assumption that high molecular weight proteins—the presumed building blocks of the fiber core—are contained in the nanoglobules, it is found that the majority of slime proteins exist freely in solution. Only less than 10% of the slime proteins are contained in the nanoglobules, necessitating a reassessment of their function in fiber formation. Comparing scattering data of slime re-hydrated with light and heavy water reveals that the majority of lipids in slime are contained in the nanoglobules with homogeneous distribution. Vibrating mechanical impact under exclusion of air neither leads to formation of fibers nor alters the bulk structure of slime significantly, suggesting that interfacial phenomena and directional shearing are required for fiber formation.     

抗菌肽基因在E.Coli JM109中的克隆表达

合成5条50～70 bp的DNA片段,用"片段拼凑"的方法通过三步PCR扩增得到目的基因,天蚕素基因被克隆到PUC19载体上,再转化大肠杆菌JM109.电泳分析重组质粒,确定天蚕素基因已转化到JM109上.摇床发酵转化子,IPTG诱导表达目的肽,最后提纯表达产物.SDS-PAGE电泳分析表明有特异性带出现,荧光色谱分析表明表达肽与目的肽组成一致,最后确定天蚕素在JM109中得到表达.抑菌圈活性实验表明,表达肽具有一定抗菌活性.