groESL启动子提高集胞藻6803外源egfp基因表达效率的研究

利用聚球藻7942中热激蛋白基因groESL的启动子(PgroESL)驱动外源egfp基因在集胞藻6803(Syn-echocystis sp.PCC6803)中的表达,通过蛋白免疫印迹技术研究不同温度条件下该外源基因的表达情况。结果表明,42℃诱导30min后,PgroESL启动子能显著提高转基因藻Pg中外源egfp基因的表达,使外源基因的表达量比正常温度条件下提高3.4倍。研究表明,聚球藻7942中groESL操纵子的启动子区域是一类可以受温度诱导的强启动子,能够显著提高宿主细胞中外源基因的表达效率。     

增强型绿色荧光蛋白在集胞藻6803中的表达

利用聚球藻7942热休克基因groESL的启动子和报告基因egfp,构建了表达载体pUC-Tegfp并转化集胞藻6803,并通过所制备抗体对转基因藻进行蛋白免疫印迹检测.结果发现,在转基因藻株T-egfp的细胞粗提液中含有能与eGFP抗体特异结合的蛋白质,表明外源增强型绿色荧光蛋白基因(egfp)在集胞藻6803中成功表达.     

集胞藻6803藻胆体别藻蓝蛋白多克隆抗体的制备

藻胆体是蓝藻细胞主要的捕光天线色素超分子复合体,主要由核心体和外围的杆两部分组成,核心体主要由别藻蓝蛋白组装而成,参与光能向光合作用反应中心的传递.该研究通过PCR扩增出集胞藻6803别藻蓝蛋白α亚基(ApcA)编码基因apcA,构建表达质粒pET-32a(+)-apcA,并将其转入大肠杆菌BL21(DE3)pLysS菌株中;通过IPTG诱导表达重组蛋白,并利用组氨酸标签将可溶性目的蛋白进行亲和纯化后,免疫日本大耳白兔,从而获得多克隆抗体.间接ELISA法揭示ApcA抗体效价可高达1∶1 025 000;蛋白免疫印迹确定该抗体具有高度特异性.表明该研究成功制备了集胞藻6803藻胆体别藻蓝蛋白多克隆抗体,为进一步研究藻胆体的核心体在光能传递过程中所承担的重要生理角色奠定了生化基础.     

植物光系统II放氧复合体外周蛋白结构和功能的研究进展

光合放氧是植物光系统II(PSII)的重要功能之一。PSII的放氧反应主要是由PSII氧化侧的 4个锰原子组成的锰簇催化的。在类囊体膜的囊腔侧还结合有若干个外周蛋白 ,对放氧反应起着重要作用。文章总结了植物光系统II外周蛋白的结构和功能研究方面的最新进展     

植物光系统Ⅱ放氧复合体外周蛋白结构和功能的研究进展

光合放氧是植物光系统Ⅱ(PSⅡ)的重要功能之一.PSⅡ的放氧反应主要是由PSⅡ氧化侧的4个锰原子组成的锰簇催化的.在类囊体膜的囊腔侧还结合有若干个外周蛋白,对放氧反应起着重要作用.文章总结了植物光系统Ⅱ外周蛋白的结构和功能研究方面的最新进展.     

利用同源重组构建蓝藻集胞藻6803ndhO基因突变株及其分子鉴定

蓝藻NADPH脱氢酶(NDH-1)是一种重要的光合膜蛋白复合体,参与CO2吸收、围绕光系统I的循环电子传递和细胞呼吸。迄今为止,人们在蓝藻细胞中已鉴定出15种NDH-1复合体亚基(NdhA-NdhO)。然而,人们对NdhO亚基的研究尚不够,至今未见有反向遗传学等方面的研究。在通过构建同源重组载体、自然转化和多次继代筛选后,对转化子进行了PCR和蛋白免疫印迹鉴定。结果表明,卡那霉素基因已成功地插入到ndhO基因的保守区域,并完全破坏了ndhO基因的蛋白表达,从而获得了ndhO基因缺失的突变株,为进一步研究NdhO亚基对NDH-1复合体的稳定性和生理功能等奠定了实验基础。     

蝶蛹金小蜂热激蛋白家族基因表达与热保护功能

作为分子伴侣, 热激蛋白可起修复变性蛋白与阻止其他蛋白质聚集的作用。为进一步理解蝶蛹金小蜂Pteromalus puparum热激蛋白家族的分子伴侣功能, 本研究对来自该寄生蜂的热激蛋白Pphsp90, Pphsp70, Pphsc70, Pphsp60, Pphsp40和Pphsp20的基因在大肠杆菌Escherichia coli BL21菌株中进行了过表达。结果表明： 除Pphsp40外, 其余5个基因均得到高效表达, 且表达的重组热激蛋白在高温下（80℃）具可溶性与热稳定性。其中, Pphsp20与Pphsp90在大肠杆菌中的表达显著提高了高温下（50℃, 1 h）细胞的存活率。离体活性实验证实, 利用纯化的融合蛋白Pphsp20可减少高温下荧光素酶的聚集现象。据此认为, Pphsp20与Pphsp90均具有大肠杆菌细胞的热保护功能, 但Pphsp20可以单独发挥作用, 而Pphsp90可能需其他因子协同作用才有保护活性。     

动物热激转录因子的进化类型及其功能研究进展

生物体暴露在高温和其它一些化学或者生理胁迫的环境中能诱导机体产生热激蛋白.真核生物中热激蛋白基因的表达受热激转录因子的调节.正常生长条件下,热激转录因子呈无活性的单体状态,当生物体处在热激等胁迫环境中时,热激转录因子会立即转换成有活性的三聚体并进入细胞核中与热激蛋白基因的热激元件结合,从而激活热蛋白激基因的转录.综述了近年来4种热激转录因子在生物体热应激反应中的作用,重点讨论了热激转录因子家族成员功能上的新发现.     

植物光系统Ⅱ放氧复合体外周蛋白结构和功能的研究进展

光合放氧是植物光系统Ⅱ（PSⅡ）的重要功能之一。PSⅡ的入氧反应主要是由PSⅡ氧化侧的4个锰原子组成的锰簇催化的。在类囊体膜的囊腔侧还结合有若干个外周蛋白,对放氧反应起着重要作用。文章总结了植物光系统Ⅱ外周蛋白的结构和功能研究方面的最新进展。     

集胞藻6803NdhO蛋白多克隆抗体制备及其初步应用

蓝藻NADPH脱氢酶(NDH-1)是一种重要的光合膜蛋白复合体,参与CO2吸收、围绕光系统I的循环电子传递和细胞呼吸.迄今为止,人们在蓝藻细胞中已鉴定出17种NDH-1复合体亚基(NdhA-NdhQ).最近,人们还获得了NdhO亚基的缺失突变株.然而,人们对NdhO亚基的研究还不充份,至今仍不清楚它的功能角色.通过PC...     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.