辣椒多聚半乳糖醛酸酶基因CaPG的克隆与序列分析

以耐贮辣椒品系P98为材料,采用RACE方法,首次获得辣椒果实多聚半乳糖醛酶(PG)基因的全长cDNA,命名为CaPG,登录号为FJ596175.序列分析结果表明,该基因cDNA长1 668 bp,5′非编码区为119 bp,3′非编码区为442 bp,CDS长1 107 bp,编码368个氨基酸.Blast比对发现,该基因核苷酸序列与已报道的番茄和番木瓜PG基因具有84%和85%的相似性.聚类分析表明,该基因与番茄和番木瓜的亲缘关系较近,与拟南芥PG基因的亲缘关系较远.     

白桦肌动蛋白(Actin)基因全长cDNA克隆与序列分析

以白桦(Betula platyphylla Suk.)次生木质部为材料,用改良CTAB方法提取总RNA。根据植物肌动蛋白(Actin)基因编码区的保守序列设计引物后进行RT-PCR,并采用RACE技术扩增出Actin基因全长序列。该基因cDNA全长1 785 bp,序列分析表明,该基因编码区1 134 bp,编码377个氨基酸,5′非编码区157 bp,3′非编码区495 bp。所得序列与GenBank中注册的其它植物肌动蛋白核苷酸序列的相似性均在80%以上,氨基酸序列的相似性高达96%以上。此基因已在GenBank注册（EU588981）。根据高等植物肌动蛋白相似性构建了进化树,表明白桦肌动蛋白与蓖麻肌动蛋白之间的亲缘关系最为密切,在进化中分化时间最为接近。     

金花茶查尔酮合成酶基因全长克隆与序列分析

利用RT-PCR和RACE方法,从我国珍稀植物金花茶(Camellia nitidissima)花瓣中获得了查尔酮合成酶(chalcone synthase,CHS)基因的cDNA全长,命名为Cn-CHS,GenBank登录号HQ269804.碱基序列分析表明,Cn-CHS全长1 454bp,包含77 bp的5'非翻译区、207 bp的3'非翻译区和一个长为1 170 bp编码389个氨基酸的开放阅读框.氨基酸序列分析显示该基因编码的蛋白具有CHS家族保守存在的所有功能活性位点和特征性多肽序列.氨基酸序列比对分析表明,CnCHS与蔷薇科、杜鹃花科、茄科等植物的CHS相似性都在92%以上;与山茶科山茶属物种山茶(C.japonica)CHS完全一致;与茶(C.sinensis)CHS相似性达99%,有5个氨基酸位点存在差异,其中包括一个功能性位点.     

百合ACC氧化酶基因全长cDNA的克隆及序列分析

以亚洲百合Polyanna(Liliumspp.)花瓣为材料,根据已报道的百合ACC氧化酶基因片段设计1对末端扩增特异引物,采用RACE方法,获得百合ACC氧化酶基因的全长cDNA(GenBank登录号为EU296623).该cDNA全长1 152 bp,具有一个954 bp的开放阅读框,编码318个氨基酸.Blast搜索结果显示,百合ACC氧化酶基因核苷酸序列与其它植物已报道的ACC氧化酶基因具有71%~82%的相似性,氨基酸序列有70%~87%的相似性,聚类分析表明,与单子叶植物百合科郁金香首先聚类,其次与双子叶植物聚类,最后与单子叶禾本科和兰科植物聚类.     

绞股蓝鲨烯环氧酶基因的克隆与序列分析

根据已报道植物鲨烯环氧酶(squalene epoxidase,SE)基因cDNA序列的保守区域设计引物,利用RT-PCR和RACE技术,对绞股蓝SE基因进行克隆及序列分析.结果表明,绞股蓝SE基因cDNA全长为1 818 bp,编码一个由525个氨基酸残基组成的多肽.绞股蓝SE基因编码的氨基酸序列中含有52.4%的非极性疏水性氨基酸,26.1%极性中性氨基酸,9.0%酸性氨基酸,12.6%碱性氨基酸.Blast结果显示,绞股蓝SE基因核苷酸序列与其他已报道的植物SE基因相似性为73%～82%,推导的氨基酸序列相似性为63.2%～79.4%.SE氨基酸序列进化分析发现,绞股蓝SE与绿珊瑚、拟南芥亲缘关系较近.     

牡丹PsCS基因的克隆及序列分析

以牡丹品种‘赵粉’(Paeonia suffruticosa L.cv.‘Zhao Fen’)为试材,采用RT-PCR和RACE方法从雄蕊中获得了一个牡丹柠檬酸合成醇(citrate synthase,CS)基因cDNA全长,命名为PsCS,GenBank登录号为HQ449568.其cDNA全长1 564 bp,包含75 bp的5’非编码区、73 bp的3 '非编码区和一个长度为1 416 bp编码471个氨基酸的开放阅读框.序列比对和系统进化分析表明,PsCS与葡萄的亲缘关系最近,相似性达89.4％以上.     

柑橘果糖激酶基因的克隆及表达

植物果糖激酶(FRK)在果糖磷酸化中起重要作用.通过PCR技术从温州蜜柑(Citrus unshiu Marc.)基因组中扩增得到编码果糖激酶基因的2个基因组DNA片段,分别命名为Cufrk1、Cufrk2,利用RT-PCR从果实中分离到了与Cufrk1外显子序列一致的cDNA序列,并通过RACE技术分离到这个基因的全长cDNA序列,命名为CuFRK1(GenBank号:AY561840).Cufrk1与Cufrk2编码氨基酸序列相似性为68%.CuFRK1 cDNA全长为1 459 bp,5'端和3'端的非翻译区分别为167 bp和239 bp,该序列含有一个完整的开放读码框,编码350个氨基酸,蛋白质分子量约为37.5 kD,等电点为5.03,含有2个果糖激酶糖特异结合域及3个ATP结合域,其氨基酸序列与其他植物中已分离的果糖激酶基因相似性在62%～78%.Northern分析显示,CuFRK1(Cufrk1)与Cufrk2在柑橘幼叶、发育初期果实中表达量较高,在果皮和茎中不表达,在花瓣及成熟果实中表达模式有一定差异.酶活性分析表明,果实中的果糖激酶活性随果实的发育而降低,同时,果实中的果糖不断积累,在果实整个发育过程中果糖含量与果糖激酶活性呈极显著负相关.     

羊草OEE1基因的克隆及盐胁迫下的表达

从羊草(Leymus chinensis )叶片cDNA文库中克隆得到可能编码33 kD的光系统Ⅱ(PSⅡ)外周蛋白(oxygen-evolving enhancer protein1,OEE1)全长cDNA(GenBank登录号为EF583851),命名为LcOEE1.序列分析结果表明,该cDNA全长1 107 bp,5′非编码区为32 bp,3′非编码区为71 bp,编码区长987 bp,编码328个氨基酸.BALSTp比对发现,该基因氨基酸序列与已报道的小麦和水稻中的OEE1序列具有95%和94%的相似性.聚类分析表明,该基因与小麦和水稻的亲缘关系较近,与拟南芥和菠菜OEE1基因的亲缘关系较远.Northern杂交结果表明,在200 mmol/L的NaCl处理7 d的幼叶中,OEE1 mRNA的表达量明显高于未处理的对照,说明羊草中OEEl基因受盐诱导.     

糜子抗旱节水相关基因PmMYB的克隆及表达分析

根据在糜子抗旱节水分子基础研究中获得的一个糜子MYB基因的EST序列, 以其序列及水稻MYB18基因的序列为基础设计引物, 扩增得到1 739 bp的全长基因组序列。序列分析表明, 其包含121 bp(347~467 bp)和93 bp(599~691 bp)的两个内含子, 3个外显子; 全长cDNA序列为1 525 bp, 其中3′非翻译区为212 bp, 5′非翻译区为41 bp, 编码区为1 272 bp, 共编码424个氨基酸, C-端存在一个丝氨酸(Ser, S)丰富区。该基因具有两个典型的MYB类转录因子基因的DNA结合区(DNA-binding domain), 分别为13~63、66~114位氨基酸, 属于典型的R2R3-MYB转录因子。对其与水稻、玉米、火炬松、拟南芥、辣椒、陆地棉、大麦及茄子等9种植物的MYB基因的R2、R3重复区的氨基酸序列多重比较, 表明R2R3重复序列在植物中具有较高的保守性; 基于氨基酸序列的编码区系统进化树分析表明, 不同植物的MYB基因遗传分化很大, 序列相似性为32%~84%, 其中糜子MYB基因与水稻的MYB18相似程度最高(84%), 与大麦和玉米的相似性分别为46%和41%。通过半定量RT-PCR对其表达模式分析表明, 该基因在水分胁迫和干旱后复水条件下上调表达, 与糜子抗旱节水紧密相关。该基因的克隆为进一步探讨利用该基因改良其他植物的抗旱节水性奠定了良好的基础。     

星星草cDNA文库构建和金属硫蛋白(MT-1)基因的克隆

以受NaHCO3胁迫后的星星草叶片组织为材料构建了cDNA文库,文库的初始滴度为2.0×106pfu,重组率为95%,平均插入片段长度为0.8kb,扩增后文库的滴度为4.0×109pfu.mL-1.文库克隆随机测序获得了星星草的金属硫蛋白(MT-1)基因的全长cDNA序列,显示文库中含有一定量的全长基因.MT-1基因全长622bp,其中5'非翻译区57 bp,3'非翻译区343 bp,开放读码框长222 bp,编码73个氨基酸,氨基酸序列中具有植物MT-1蛋白特有的金属响应元件(MRE)序列,MT-1蛋白的分子量为7.814 kD,理论等电点为4.72.     

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).     

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.