油茶柠檬酸合成酶(CS)基因的克隆和表达分析

采用RT-PCR技术从油茶中分离出一个柠檬酸合成酶基因,该基因的c DNA全长1 416 bp,编码471个氨基酸,推导的蛋白分子量为52.74 k D,理论等电点(PI)为6.95。同源比对显示其与其他植物的CS蛋白序列高度同源,将该基因命名为Co CS(Gen Bank登录号:KU161147)。系统进化树分析表明油茶Co CS与杜鹃和葡萄的CS蛋白的亲缘关系较近。荧光定量PCR分析结果表明,油茶受到低磷胁迫后根系Co CS基因的表达受到低磷诱导,表达量呈现先升高后降低的趋势;不同油茶品种不同组织(根、茎、叶)中的Co CS基因在不用磷处理下的表达模式不同。     

油茶3羟酰CoA脱水酶基因的克隆与表达分析

3羟酰CoA脱水酶是一类催化3羟酰CoA脱水转化成为烯酰CoA形式的酶。本研究以国审油茶品种‘华硕’种子为材料,在已构建的转录组和表达谱数据库的基础之上,采用RACE技术,克隆到一个油茶3羟酰CoA脱水酶基因的cDNA全长,命名为CoHCD(Gen Bank登录号KJ910336)。该基因cDNA全长为1145bp,含有666bp的开放读码框,编码221个氨基酸,分子量为25.2kDa,理论等电点p I为9.4,疏水残基占整个氨基酸残基的48.9%,是亲水性蛋白,具有4个比较明显的跨膜区和蛋白质酪氨酸磷酸酶基序"HGXXGXXRS"。在基因c DNA全长序列的基础上,分别成功地构建了原核表达载体、超表达载体和RNA干扰载体,其中,原核表达载体在宿主细胞BL21(DE3)上成功诱导表达,获得表观分子量约为25 k Da的相应目的蛋白。实时荧光定量PCR分析表明,在5个不同发育时期的油茶种子中CoHCD高效表达主要集中在8~10月,转录最高峰发生在9月,其表达量在种子发育过程中呈增加趋势。     

油茶长链脂肪酰基CoA合成酶基因1(CoLACS1)分子特征与表达分析

长链脂肪酰基Co A合成酶(LACS)在脂肪酸的合成与分解代谢中起着重要作用。本研究以油茶(Camellia oleifera Abel)国家审定品种华硕(Camellia oleifera Huashuo)种仁转录组数据为基础,根据LACS基因Unigene序列设计引物,分离克隆了油茶LACS1基因全长c DNA序列,命名为CoLACS1(Gene Bank登录号:KJ960228),全长2114 bp,开放阅读框2088 bp,编码695个氨基酸;生物信息学分析显示CoLACS1具有3个B1ock,从分子特征可判断CoLACS1属于LACS家族;氨基酸同源比对显示与其他物种的LACS氨基酸序列具有较高的相似性,其中与拟南芥LACS7相似性为78%,与麻风树、大豆、毛果杨等物种LACS6(peroxisomal)相似性可达80%以上;对CoLACS1进行原核表达分析,构建的p ET30a-CoLACS1载体成功转化至BL21(DE3)中经1 mmol/L IPTG诱导表达,菌液检测获得预测的目的蛋白(分子量约为76 k D);分析转录组数据中CoLACS1的Unigene序列RTKM值并对CoLACS1进行实时荧光定量PCR分析,结果表明CoLACS1在油茶华硕种子发育各时期平稳表达,表达丰度变化不大,荧光定量结果变化规律与转录组数据分析一致;同时分析华硕种仁不同时期含油率和脂肪酸成分变化,双变量统计分析发现CoLACS1表达模式与油茶油脂积累规律呈显著相关性。本研究为进一步研究油茶油脂积累与代谢的基因调控提供理论依据。     

柔嫩艾美耳球虫保守蛋白CHP559基因克隆与真核表达

为构建柔嫩艾美耳球虫保守蛋白Et CHP559基因的真核表达重组质粒pc DNA3.1-flag-Et CHP559,并转染DF-1细胞进行表达。利用5'RACE技术克隆获得了柔嫩艾美耳球虫Et CHP559基因全长c DNA序列,该基因全长为1 746 bp,ORF为104-1 327 bp,编码407个氨基酸,编码蛋白的分子量约为46 k D,并利用生物信息学分析该基因编码蛋白的性质、结构等特征,发现该蛋白含有跨膜结构和信号肽。通过RT-PCR扩增得到含完整开放阅读框的基因片段,并将其与真核表达载体pc DNA3.1-flag连接,构建了真核重组表达质粒pc DNA3.1-flag-Et CHP559,所构建的真核重组表达质粒pc DNA3.1-flag-Et CHP559经过PCR和双酶切鉴定,可见一条大小约为1 224 bp的目的条带;重组质粒转染DF-1细胞后,免疫印迹检测可见大小约为47 k D的目的蛋白条带,间接免疫荧光实验显示在DF-1细胞中检测到绿色荧光。这些研究结果表明已成功获得了Et CHP559的全长序列,并成功构建了Et CHP559的真核重组表达质粒,在真核细胞DF-1中获得表达,为深入研究Et CHP559的功能奠定了基础。     

杂色鲍两种perlucin基因的克隆与表达分析

利用SMART RACE技术克隆杂色鲍两个甘露聚糖结合型凝集素(mannan-binding lectin,MBL)成员perlucin1和perlucin4基因的全长c DNA序列,使用Real time PCR分析这些基因在杂色鲍不同组织中的表达。结果显示,杂色鲍perlucin1 c DNA序列全长为668 bp,165个氨基酸,经分析该基因含有2个二硫键、2个糖基化位点和13个磷酸化位点,预测蛋白分子量约为18.8 k D,等电点约为4.57;perlucin4 c DNA序列全长为587 bp,156个氨基酸,含有2个二硫键、1个糖基化位点和7个磷酸化位点,预测蛋白分子量约为17.8 k D,等电点约为4.43;鳃、肝胰腺、血淋巴、上足、外套膜、黏液腺、肾脏7个组织中,perlucin1基因和perlucin4基因只有在肝胰腺中表达,在其它组织中没有检测到表达。结果表明,perlucin基因参与了杂色鲍天然免疫防御机制,在免疫识别中发挥着重要作用。     

红笛鲷p38β MAPK基因的克隆及原核表达

鱼类p38 MAPK基因在宿主免疫调控及抵御病原侵染的过程中具有重要作用。利用RACE技术克隆了红笛鲷p38βMAPK基因(Ls-p38β,Gen Bank登录号为KJ502277)。序列分析结果显示,Ls-p38βc DNA全长1 628 bp,开放阅读框1 086 bp,可编码361个氨基酸,预测其编码蛋白的分子量为41.6 k D,理论等电点为5.74。该基因推导的氨基酸序列含有p38 MAPK家族保守的双磷酸化激活环(TGY),与尼罗罗非鱼的p38β有97%的相似性。将此基因定向插入原核表达载体构建重组表达质粒p ET32-p38β后导入BL21(DE3)菌株,利用IPTG进行诱导表达。SDS-PAGE与Western blot分析显示约在60 k D出现特异蛋白条带,与预期分子量大小相符,说明Ls-p38β融合蛋白表达成功。     

水稻泛素连接酶基因OsRING6的克隆及表达分析

RING(Really Interesting New Gene)型泛素连接酶在水稻生长、发育、生物和非生物胁迫中发挥着重要作用。根据水稻基因组信息,利用RT-PCR技术从粳稻日本晴中克隆了OsRING6基因的CDS序列。该基因的全长c DNA为1355 bp,包括长度为918 bp的CDS,编码一个含305个氨基酸的蛋白,预测该蛋白的分子量和等电点分别为32.96 k D和3.49,与籼稻(CT832014)和短花药野生稻(XM_006659599)中同源蛋白的序列相似性最高,分别为97%和83%。IPTG诱导表达的MBPOsRING6重组蛋白的表观分子量约为100 k D,比理论值76 k D大。启动子元件分析表明,其含有与干旱胁迫、光反应、ABA和GA信号传导相关的调控元件。Real-time PCR结果表明,该基因在水稻根、茎、叶、叶鞘、花和种子中都有表达,在萌发后4 d的种子中表达量最高,花中的表达量最低,且该基因的表达受到盐和ABA的诱导及PEG的抑制。OsRING6基因的克隆为水稻抗逆分子育种和功能分析提供了优质基因资源。     

家蝇Thymosin(THY)基因的克隆及原核表达

采用EST测序技术从构建的家蝇(Musca domestica)幼虫c DNA质粒文库中筛选到胸腺肽(Thymosin,THY)基因,以该基因的c DNA文库质粒为模板,设计引物,通过PCR扩增,测序鉴定,获得THY基因完整编码序列。运用生物信息学方法对该基因及其编码蛋白的基本理化性质、信号肽和亚细胞定位等方面进行预测和分析。构建p ET-28a(+)-THY重组质粒,转化到大肠杆菌BL21(DE3)中进行诱导表达。研究结果表明,THY基因ORF全长384 bp,编码127个氨基酸,理论分子量14.3 k D,等电点为5.22,具有THY家族的蛋白保守结构域。构建重组原核质粒p ET-28a(+)-THY,经IPTG诱导,蛋白在大肠杆菌中获得表达,经亲和层析柱纯化获得目的蛋白,Western blot检测发现纯化的目的蛋白大小正确。     

无籽刺梨(Rosa kweichonensis var.sterilis)RksAGL基因克隆及表达分析

以无籽刺梨(Rosa kweichonensis var.sterilis)花芽提取的RNA为模板,采用同源克隆结合RACE技术克隆得到无籽刺梨AGL基因的c DNA全长,命名为Rks AGL。序列分析表明,c DNA全长1 089 bp,开放阅读框长度为747 bp,可编码248个氨基酸。编码蛋白分子质量预测为28.56 k D,等电点为9.40,无信号肽序列。分析表明,Rks AGL基因属于MADS-box基因家族C类基因,其编码的蛋白与其它植物AGAMOUS类蛋白具有较高的同源性。实时定量PCR分析表明,RksAGL基因仅在雄蕊和心皮中表达,在萼片和花瓣中不表达     

斜带石斑鱼IL-10基因的克隆及其原核表达

白介素10(Interleukin-10,IL-10)是一个重要的多效细胞因子,主要作用是介导炎症反应和调控一些免疫细胞的分化和增殖。利用同源克隆和RACE-PCR技术获得全长为1 104 bp的斜带石斑鱼(Epinephelus coioides)IL-10基因。该基因ORF为564 bp,编码187个氨基酸,预测蛋白分子量为21.7 k D,等电点为5.74。氨基酸同源性比对及进化分析结果显示,斜带石斑鱼IL-10氨基酸序列和吉富罗非鱼(O.niloticus)同源性最高,达72.25%。利用双酶切及质粒重组技术构建IL-10原核表达载体,并转化大肠杆菌BL21(DE3)中诱导原核表达。SDS-PAGE分析显示,融合蛋白分子量为37.5 k D,与预期相符;在IPTG为0.02mmol/L,37℃诱导3 h,蛋白包涵体的表达量最大。     

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.     

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     

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.     

鸡传染性法氏囊病病毒研究进展

传染性法氏囊病(Infection bursal disease, IBD)是由鸡传染性法氏囊病毒(Infectious bursal disease virus, IBDV)引起的鸡和火鸡的一种高度接触性传染病,给世界各国的禽养殖业带来了巨大损失.自IBDV发现至今新的变异株不断出现,分子结构的改变导致病毒致病力的改变及宿主对疫苗应答的改变,使得传统的疫苗已不能控制其流行,因此各国学者对其基因组结构和功能进行了广泛深入的研究,并积极研制新型有效的疫苗以达到防治的目的.     

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.     

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).