人重组GDNF及其生物活性研究

从人胎脑组织中提取总ＲＮＡ,以ＲＴ－ＰＣＲ方法获取编码胶质细胞源神经营养因子（ＧＤＮＦ）成熟蛋白的ｃＤＮＡ。将人ＧＤＮＦｃＤＮＡ插入含Ｔ７启动子的质粒ｐＥＴ－２８ａ（＋）,构建表达质粒ｐＥＴ－ＧＤＮＦ,转化大场杆菌获得表达菌株ＢＬＧＤＮＦ,经诱导表达的ＧＤＮＦ形成包含体。凝胶自动扫描分析表明,表达量约占菌体总蛋白的３０％以上。用纯化的ＧＤＮＦ蛋白免疫新西兰兔制备了ＧＤＮＦ抗血清。纯化和复性的ＧＤＮ     

重组人粒-巨噬细胞集落刺激因子的实验室培养、复性和分离纯化

建立了一个实验室制备重组ｈＧＭ-ＣＳＦ的培养、复性和分离纯化的技术工艺。通过对ＰＥＧＭ工程菌的生长和诱导表达等条件的初步调整,使ｈＧＭ-ＣＳＦ的表达量从１６.９％提高到３２.３％,获得０.７４９ｇ／Ｌ的包含体,纯度为６５％;包含体用６ｍｏｌ／Ｌ盐酸胍溶解和稀释复性后,经ＣＭＳｅｐｈａｒｏｓｅＦＦ．ＤＥＡＥＳｅｐｈａｒｏｓｅＦＦ和ＳｅｐｈａｃｒｙｌＳ２００ＨＲ层析分离,制得纯度达９７％以上、比活性为３.０×１０^７ｕ／ｍｇ的ｈＧＭ-ＣＳＦ,纯化总回收率约为５％     

人睫状神经营养因子基因及突变体在大肠杆菌中的表达

人睫状神经营养因子（ｈｕｍａｎ ｃｉｌｉａｒｙ ｎｅｕｒｏｔｒｏｐｈｉｃ ｆａｃｔｏｒ,ｈＣＮＴＦ）ｃＤＮＡ克隆入具有ＰＬ启动子的表达载体,转化大肠杆菌ＨＢ１０１,构建成表达ｈＣＮＴＦ菌株。热诱导后,ｈＣＮＴＦ的表达量达菌体总蛋白量的２５％。用离子交换层析、凝胶过滤层析从菌体裂解液中纯化了ｈＣＮＴＦ。ＳＤＳ－ＰＡＧＥｈＣＮＴＦ的分子量约为２４ｋｄ,Ｎ端氨基酸序列分析结果与依基因核苷酸推导疗列相符。     

神经营养因子GDNF编码顺序的克隆及表达产物的纯化

根据基因库中的顺序,设计了胶质细胞源神经营养因子（ＧＤＮＦ）基因的ＰＣＲ引物,以此从人基因组ＤＮＡ中扩增并克隆了ＧＤＮＦ的编码序列,经ＤＮＡ测序确认后,该片段克隆到表达质粒ｐＥＴ－３ａ中,转化大肠杆菌ＢＬ２１（ＤＥ３）．培养的重组菌经ＩＰＴＧ诱导,在Ｔ７启动子调控下表达出ｈＧＤＮＦ蛋白．经电泳分析表明ＧＤＮＦ主要存在于细菌包涵体中．从培养菌中制备包涵体,经充分洗涤,溶解于含８ｍｏｌ／Ｌ尿素的变性缓冲液中．经ＳＰ－Ｓｅｐｈａｒｏｓｅ柱层析分离,梯度洗脱,以１５％ＳＤＳ－ＰＡＧＥ检查含ＧＤＮＦ的部分．将含单体ＧＤＮＦ部分进行复性,再次用ＳＰ－Ｓｅｐｈａｒｏｓｅ离子柱分离同源二体ＧＤＮＦ．最后经ＳＤＳ－ＰＡＧＥ制备电泳纯化,纯度大于９５％．经Ｎ端测序表明序列正确．经测定,每升培养菌可得约１０ｍｇ纯化的ＧＤＮＦ．     

抗HBsAg二硫键稳定性Fv抗体（dsFv）基因的构建与表达

采用ＰＣＲ定点突变方法,成功地构建了抗ＨＢｓＡｇｄｓＦｖ抗体的轻、重链突变基因,ＮｄｅＩ和ＥｃｏＲＩ酶切后分别插入ｐＥＴ２０ｂ表达质粒,经测序证明在重链第４４位氨基酸和轻链第１００位氨基酸已突变形成半胱氨酸（Ｃｙｓ）。ＶＨ和ＶＬ重组质粒分别转化到大肠肝菌ＢＬ２１（ＤＥ３）中,ＩＰＴＧ诱导后,经ＳＤＳＰＡＧＥ电泳表明在１２ｋＤ处有包含体蛋白表达,表达蛋白含量分别为２８％和３５％。ＶＨ和ＶＬ包含体蛋白经ＧｕＨＣｌ变性后,等量混合在复性折叠液中结合,形成了一个约２４ｋＤ并有一定活性的ｄｓＦｖ蛋白。抗ＨＢｓＡｇｄｓＦｖ抗体表达及复性的成功,为今后基因工程抗体的研究及应用奠定了基础。     

白细胞介素—2—绿脓杆菌外毒素融合蛋白的分高纯化及其复性研究

表达的白细胞介素－２－绿脓杆菌外毒素（ＩＬ－２－ＰＥ）融合蛋白以包含体形式存在于宿主菌中,为分离纯化表达产物提供了方便,但因需进行复性,也增加了后处理的难度．我们采用４ｍｏｌ／Ｌ尿素、０．５％ＴｒｉｔｏｎＸ－１００的１×ＰＢＳ洗涤包含体两遍,再经ＳｅｐｈａｃｒｙｌＳ－３００分子筛及ＤＥＡＥ－ＳｅｐｈａｒｏｓｅＦＦ阴离子交换柱层析后,获得的融合蛋白纯度可达９０％～９５％。此外,我们从ＧＳＳＧ浓度、Ｌ－精氨酸浓度、复性蛋白质的起始浓度、复性液的ｐＨ值、复性温度及复性时间等参数入手,系统地研究了融合蛋白的复性条件,探索到了ＩＬ－２－ＭＥ４０和ＩＬ－２－ＰＥ６６４Ｇｌｕ融合蛋白复性的最适条件。     

人促红细胞生成素受体胞外区基因的克隆及其在大肠肝菌中的表达

以人胎肝为材料,通过ＰＴ－ＰＣＲ的方法扩增出人促红细胞生成素受体（ｈＰｅｏＲ）的胞外区基因。将获得的或熟体胞外区基因起始密码子改构后克隆原核表达载体ｐＢＶ２２０中,进行原核温控诱导表达。表达产物经蛋白Ｎ端测序及Ｗｅｓｔｅｒｎ－ｂｌｏｔ实验证实表达产物是ｈＥｐｏＲ胞外区蛋白。利用上罐发酵培养获得的包涵体蛋白经复性纯化后,体外生物学活性检测表明表达产物可特 抑制ＴＦ－１细胞在Ｅｐｏ刺激下的生长,证实了     

人GM—CSF cDNA的克隆和在大肠杆菌中的表达

从诱导的人胚肺细胞ＨＦＬ株中提取总ＲＮＡ．经ＲＴ－ＰＣＲ反应获取了人ＧＭ－ＣＳＦｃＤＮＡ,ＤＮＡ序列测定表明其顺序与文献报道完全一致。为了获得高效表达,应用ＰＣＲ改造了人ＧＭ－ＣＳＦ的ｃＤＮＡ５’端核苷酸序列,并将改造的人ＧＭ－ＣＳＦ基因插入含Ｔ７启动子的质粒ｐＥＴ－１１ｄ构建成表达质粒ｐＥＴＣ－５,将此质粒转化大肠杆菌株ＢＬ２１（ＤＥ３）得到表达菌株ＢＬＥＣ４。表达菌株用０．５ｍｏｌ／ＬＩＰＴＧ诱导２小时后,产生大量重组蛋白并形成包涵体。ＳＤＳ—ＰＡＧＥ电泳图谱扫描结果表明,ｒｈＧＭ－ＣＳＦ产量占菌体总蛋白量的１６％。ＥＬＩＳＡ和ＴＦ－１细胞培养测定表明,初步纯化和复性的ｒｈＧＭ－ＣＳＦ具有天然的ｈＧＭ－ＣＳＦ生物活性。     

人睫状神经营养因子突变体基因克隆及高效表达

为了提高人睫状神经营养因子（ＣＮＴＦ）的生物学活性,用ＰＣＲ方法获取Ｎ端缺失１４个氨基酸的ＣＮＴＦ基因片段,经酶切鉴定、核酸测序证实突变体的核苷酸序列,将其重组至表达质粒ｐＢＶ２２０,构建了ＣＮＴＦ突变体表达载体ｐＢＶ－ＣＮＴＦΔ．用ＳＤＳ－ＰＡＧＥ测定其表达水平,鸡胚背根节无血清培养法检测表达蛋白的生物学活性．结果表明,ｐＢＶ－ＣＮＴＦΔ能表达生物学活性高于天然ＣＮＴＦ的约２６ｋＤ蛋白质,表达水平达３０％．为今后通过基因工程方法获得ＣＮＴＦ突变体,从而制备高效的ＣＮＴＦ制剂创造了条件．     

江浙蝮蛇神经生长因子在大肠杆菌中的表达及纯化

将江浙蝮蛇（ＡｇｋｉｓｔｒｏｄｏｎｈａｌｙｓＰａｌａｓ,Ａ．ｈ．Ｐ．）神经生长因子（Ｎｅｒｖｅｇｒｏｗｔｈｆａｃｔｏｒ,ＮＧＦ）基因克隆于分泌型原核表达载体ｐＥＴ２２ｂ＋,以Ｃ端融合了６个组氨酸的形式在大肠杆菌ＢＬ２１（ＤＥ３）中进行了ＩＰＴＧ诱导表达。ＳＤＳＰＡＧＥ分析确定有一比理论值略大的诱导表达条带,其表达量占全菌蛋白质的２０％左右,且表达蛋白质主要是以包涵体的形式存在。用６ｍｏｌ／Ｌ的盐酸胍溶解包涵体后,利用固定化金属离子（Ｎｉ２＋）配体亲和层析一步纯化目的蛋白质,纯度可达８０％左右。对该重组肽进行变复性研究。利用ＰＣ１２细胞进行生物活力测定,证明表达产物具有ＮＧＦ生物活力。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.