新型冠状病毒考点汇总

人感染了冠状病毒后常见体征有呼吸道症状、发热、咳嗽、气促和呼吸困难等.在较严重病例中,感染可导致肺炎、严重急性呼吸综合征、肾衰竭,甚至死亡.如图1所示,冠状病毒外有包膜,这层包膜主要来源于宿主细胞膜(磷脂层和膜蛋白),但也包含有一些病毒自身的糖蛋白.膜表面有三种糖蛋白:刺突糖蛋白(S,是受体结合位点、溶细胞作用和主要抗原位点)、小包膜糖蛋白(E,与包膜结合的蛋白).     

Proapoptotic and pronecrosis effect of different truncated hepatitis C virus core proteins

Objective: To study the roles of different truncated hepatitis C virus (HCV) core proteins (CORE) in the pathogenesis of HCV persistent infection and hepatocellular carcinoma (HCC) and to assess intracellular localization in transiently transfected cells. Methods: Seven truncated CORE-GFP (green fluorescent protein) fusion protein expression plasmids were constructed,which contained HCV CORE sequences derived from tumor tissues (BT) and non-tumor tissues (BNT) from one patient infected with HCV. Amino acid (aa) lengths were BT: 1-172 aa, 1-126 aa, 1-58 aa, 59-126 aa, 127-172 aa; BNT: 1-172 aa and C191:1-172 aa respectively. Subcellular localization of CORE-GFP was analyzed by con-focal laser scanning microscope. Apoptosis and necrosis were quantified by flow cytometry. Results: Different truncated CORE-GFP localized mainly in the cytoplasm, but nuclear staining was also observed. HCV CORE could induce apoptosis and necrosis, and different truncated COREs could induce cell apoptosis and necrosis at different levels. Among the same length 1-172 aa of BT, BNT and C191, the cell apoptosis and necrosis percentage of BT is highest, and C191 is the lowest (BT＞BNT＞C191). To the different fragment COREs of BT,N-terminal of CORE induced apoptosis and necrosis higher, compared with that of C-terminal (1-172 aa＞1-126 aa＞1-58aa＞ 127-172 aa＞59-126 aa). Conclusion: These results suggest HCV CORE could induce apoptosis and necrosis of cells, which might play an important role in the pathogenesis of HCV persistent infection and HCC and the different CORE domains of different HCV quasi-species might have some difference in their pathogenesis.     

RNA和DNA之间的结构变化显示的疏水性差异

本文从分子结构上对构成RNA和DNA的糖基和碱基取代基的极性差异进行了分析,从脱氧核糖比核糖的疏水性强、胸腺嘧啶比尿嘧啶的疏水性强的实际出发,得出在一级结构上DNA的疏水性大于RNA的结论,揭示了真核细胞分裂过程中核膜的消失和重现的化学机理,并以DNA甲基化的疏水性化学修饰为基础讨论了基因的稳定性及其对肿瘤发生的影响。     

德科学家发现一种促使癌细胞分裂的蛋白

据2011年12月23日《科技日报》援引新华社柏林同月21日电,德国慕尼黑大学的研究人员发现一种名为c-Myc的核蛋白可摆脱细胞内的控制机制,促使癌细胞分裂。这种蛋白可调节细胞的生长和分裂,合成这种蛋白的基因本应在造血、胚胎发育等情况下"工作",在不需要时受细胞抑制而"休息"。但是,在癌细胞中这种基因却摆脱抑制,放肆表达,在淋巴癌和乳腺癌等癌症中甚至扮演了"制造者"的角色。     

对虾白斑病毒核糖核苷酸还原酶基因原核表达载体的构建及蛋白表达、纯化

采用PCR方法扩增对虾白斑病毒核糖核苷酸还原酶基因,插入到pGEX-4T-2表达载体上构建出带有目的基因的重组质粒pGEX-4T-2RR,然后将重组质粒转化大肠杆菌.转化菌经IPTG诱导后大量表达重组蛋白,通过降低诱导温度获得可溶性表达的重组蛋白,采用Glutathione Sepharose 4B亲和层析对重组蛋白进行纯化,获得了高纯度的目的蛋白.     

树突状细胞核蛋白1的核定位信号鉴定

根据GenBank数据库中树突状细胞核蛋白1(DCNP1)的基因序列,通过PCR体外扩增构建野生型和突变型DCNP1,与GFP结合后转染细胞表达,通过对全长的树突状细胞核蛋白1(DCNP1)及其缺失突变体进行真核表达,分析其117-119aa序列对DCNP1核定位的影响。结果表明117-119位氨基酸对该蛋白的核定位是必须的,缺失该部分的突变体在真核细胞中丧失了核定位的特性。     

有关“DNA的粗提取与鉴定”实验的几点释疑

1在不同浓度的NaCl溶液中,DNA的溶解度不同 DNA分子是由脱氧核苷酸聚合而成,每个脱氧核苷酸又由一分子含氮碱基、一分子脱氧核糖和一分子磷酸根组成。DNA分子双螺旋的骨架是由磷酸残基和脱氧核糖组成,而磷酸带负电荷,使得DNA带负电。DNA在细胞核中是以染色质或者染色体的形式存在,与DNA结合的组蛋白由于其氨基酸的组成特点,也会带电荷。在细胞核内,DNA与一些组蛋白结合形成脱氧核糖核蛋白即（DNP）,同时RNA与一些组织蛋白结合形成核糖核蛋白即（RNP）,这两种复合物都会带有一定的电荷。     

自噬在神经退行性疾病中的作用研究进展

自噬是一种广泛存在于真核细胞内的生物现象,能够清除缺陷蛋白和细胞器。神经退行性疾病大多具有特定的病理性蛋白沉积,如阿尔兹海默病及帕金森病。因此,自噬功能和神经退行性疾病有着密切联系。全面了解自噬在不同神经退行性疾病中的分子机制可为疾病的治疗和预防提供一个崭新的方向。     

Novel Mechanism to Regulate Influenza A Virus Survival

<正>Recently a group of researchers at the unit of molecular virology,Institut Pasteur of Shanghai,Chinese Academy of Sciences revealed a new mechanism to regulate the survival of influenza A virus and reported their discoveries in the Journal of Virology on July