用mtDNA序列鉴定出上海海域 须鲸科物种大村鲸

测定了采自上海海域的一头死亡须鲸骨骼样本的线粒体DNA（mtDNA）细胞色素b基因（Cyt b）序列330 bp（登录号MK295815）、细胞色素C氧化酶Ⅰ基因（COⅠ）序列206 bp（登录号MK317953）和控制区（control region）序列231 bp（登录号MK317954）。通过GenBank中的BLAST分析,结果表明,样本的上述三部分序列与大村鲸（Balaenoptera omurai）对应序列的相似性均达到100%,基于最大似然法（ML）法构建的系统发育树与BLAST结果一致,故将标本鉴定为大村鲸,为上海海域首次记录。     

用mtDNA序列鉴定一头小布氏鲸标本

测定了采自浙江省瑞安市的一头须鲸类标本的线粒体DNA（mitochondrial DNA,mtDNA)细胞色素b(cytochrome b,cyt b)基因369bp和控制区（control region)933bp的序列,通过与已发表的须鲸类同源序列比对,发现与西太平洋和日本水域的布氏鲸的cyt b基因和控制区分别有6.78%-7.05%和13.30%－14．40％的序列差异,而与来自所罗门群岛的布氏鲸之间cyt b基因的序列完全相同,控制区的序列也仅相差一个碱基（0.28%)。提示与邻近的西太平洋和日本海的普通布氏鲸在遗传上有显著区别,而可能与所罗门群岛的布氏鲸为同一种,即小布氏鲸（Balaenoptera edeni)。同时表明,应用分子生物学手段为进行鲸肉及其制品的种类鉴定是可行和有效的。     

太湖新银鱼线粒体D-loop和Cytb片段序列结构与进化速率比较

共获得49个太湖新银鱼(Neosalanx taihuensis)个体的线粒体细胞色素b(Cyt b)全序列和控制区(D-loop)部分序列。所测线粒体D-loop部分序列长度变化范围为648～680bp,识别到位于前端的一个串联重复序列、一个终止相关序列(ETAS),3个中央保守区保守序列(CSB-F、CSB-E、CSB-D)及一个保守序列区保守序列(CSB-1),结构与其他鱼类的研究结果类似。太湖新银鱼线粒体Cyt b和D-loop片段的相对进化速率的比较研究结果表明,太湖新银鱼D-loop总的序列多态性位点的比例为0.83%,低于线粒体Cyt b部分总的序列多态性位点的比例(1.31%)。假设太湖新银鱼Cyt b基因平均进化速率相对值为1,贝叶斯(Bayes)MCMC模拟给出Cyt b基因的相对速率区间估计为1.000±0.131,而D-loop基因的相对速率为0.859±0.261,表明太湖新银鱼D-loop基因的进化速率低于Cyt b基因,同时,后验概率分布的变异方差也比较大。说明Cyt b基因比D-loop基因具有相对较高的进化速率,也相对更接近分子钟假设。因此,可以认为Cyt b基因比D-loop基因更适于太湖新银鱼种内及近缘种间相关分子生态及系统地理格局的研究。     

家鸭细胞色素C氧化酶Ⅲ（COⅢ）基因的克隆及序列分析

线粒体是存在于绝大多数真核细胞内的一种基本的、重要的细胞器,是细胞进行氧化磷酸化的场所。不同脊椎动物同源基因序列的比较显示,细胞色素b(Cytb)、细胞色素C氧化酶Ⅰ（COⅠ）、细胞色素C氧化酶Ⅱ（COⅡ）、细胞色素C氧化酶Ⅲ（COⅢ） 基因最保守,同源性最高,ATPase6、ATPase8基因、ND基因变异比较大。本试验以家鸭（家鸭起源于绿头鸭：Anas platyrhynchos）肝脏的线粒体DNA为模板,按照GenBank已经公布的潜鸭族（AF090337）的全序列及其绿头鸭的mtDNA部分序列（L22476、L16770、L22477）设计合成特异引物进行PCR扩增,克隆并测定了线粒体细胞色素C氧化酶Ⅲ亚基（COⅢ）的全序列784bp以及ATPase6基因的3'端和tRNA-Gly基因的5'端序列共934bp。 用DNAStar分析软件对家鸭与GenBank中7种禽类的COⅢ序列进行比较分析,显示家鸭与这些动物的COⅢ基因具有较高的同源性,与同科潜鸭属中的Aythya Americana的相似性 最高为90.6 %,与同目不同科的加拿大雁、小天鹅、白额雁的相似性分别为89%、88.6%、88.6%。根据家鸭与其他7种禽类的COⅢ基因序列相似性所建立的进化树,与传统的分类地位基本吻合。     

雀形目15种鸟类Co Ⅰ与Cyt b基因序列的比较

对雀形目Passeriformes 6科15种鸟类线粒体DNA的Cyt b基因全序列(1 143 bp)和CoⅠ基因部分序列(1 176 bp)进行了比较,结果显示Cyt b和CoⅠ基因序列的变异位点分别为454个和366个,简约信息位点为337个和303个,而且CoⅠ基因比Cyt b基因略微保守,进化速率也较低.采用邻接法、最大简约法、最大似然法和贝叶斯法分别构建了CoⅠ和Cyt b基因两组数据集的分子系统发生树及其合一树,并对建树结果进行了比较分析.基于以上两点,本文认为CoⅠ基因比Cyt b基因更适合于确定雀形目科级阶元之间的系统发生关系,而且它也能够作为雀形目物种鉴定的分子标记,但在物种鉴定方面不如Cyt b基因稳定和准确.     

基于COⅠ、COⅡ和Cyt b基因部分序列研究斑粉蝶属(鳞翅目,粉蝶科)分子系统关系

为了探讨斑粉蝶属Delias的系统发生关系,对中国产6种斑粉蝶21只标本的细胞色素氧化酶Ⅰ(CO Ⅰ)基因(约653 bp)、细胞色素氧化酶Ⅱ(COⅡ)基因(约677 bp)和细胞色素b(Cyt b)基因(419 bp)部分序列进行了分析(共1749 bp).其中有355个变异位点,352个简约信息位点,表现出明显的A+T含量(72.61%)偏异.结合从GenBank中获得的29个种斑粉蝶的COⅠ和COⅡ基因部分序列,分别采用最大简约法(Maximum Parsimony,MP)和贝叶斯推论法(Bayesian Inference,BI)构建了斑粉蝶属分子系统树.结果表明:报喜斑粉蝶D.pasithoe和优越斑粉蝶D.hyparete关系较近,隐条斑粉蝶D.subnubila、艳妇斑粉蝶D.belladonna关系较近.此外,系统分析结果很好的支持了基于形态学分类的geraldina、cuningguti、dorimene、hyparete种组,支持将D.harpalyce从belisama种组移到nigrina种组,将D.messalina从nigrina种组移到kummeri种组.     

墨天牛属昆虫COⅠ基因比较及系统学初步研究

【目的】对11种墨天牛线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ)进行比较并对墨天牛属系统发育关系进行初步探讨。【方法】本文测定分析了11种墨天牛线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ),并采用简约法和贝叶斯推论法构建了墨天牛属的分子进化树。【结果】序列比对分析得到470 bp大小的COⅠ基因片段,其中可变异位点169个(36.0%),保守位点301个(64.0%),转换/颠换的平均值(R值)为1.03,说明此段序列适合于分子进化树。利用不同系统发育重建方法得到的进化树具有相似的拓扑结构,同时结合形态学分类特征对墨天牛属昆虫的分子系统进化关系进行探讨。结果显示分子结果与形态分类结果相似。【结论】利用COⅠ基因构建的墨天牛属系统发育树是探讨墨天牛分类的有效方法。     

斑皮蠹属昆虫COⅠ基因比较及系统学初步研究

对6种斑皮蠹线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ)进行比较并对斑皮蠹属系统发育关系进行初步探讨。本研究测定分析了6种斑皮蠹线粒体DNA细胞色素氧化酶C亚基Ⅰ基因(COⅠ),并采用简约法和贝叶斯推论法构建了斑皮蠹的分子进化树。序列比对分析得到365 bp大小的COⅠ基因片段,其中可变异位点182个(49.9%),保守位点174个(47.7%),转换/颠换的平均值(R值)为0.9,说明此段序列适合于分子进化树。利用不同系统发育重建方法得到的进化树具有相似的拓扑结构,同时结合形态学分类特征对斑皮蠹属昆虫的分子系统进化关系进行探讨。研究显示分子结果与形态分类结果相似。利用COⅠ基因构建的斑皮蠹系统发育树是探讨斑皮蠹系统学的有效方法。     

黑线姬鼠两亚种(中国东北地区及俄罗斯远东地区的东北亚种和朝鲜半岛的朝鲜亚种) 的线粒体DNA 序列缺少趋异性

为了检测黑线姬鼠两亚种(来自中国东北地区、俄罗斯远东地区的东北亚种和朝鲜半岛的朝鲜亚种)线
粒体DNA 的变异水平并确定朝鲜亚种的分类地位,我们测序分析了两亚种的线粒体DNA 细胞色素b 的部分序列
(1 054 bp)和控制区的部分序列(860 bp),并与基因库中黑线姬鼠相应的单倍型序列进行了比较。可以看出东
北亚种的序列显示出某些分异,可以被分为2 或3 个亚群,所以我们提出需要更多标本的DNA 分析来确定东北
亚种的分类地位。另外,来自韩国的朝鲜亚种的序列,与来自中国东北地区龙江和哈尔滨的东北亚种的两个亚
群相似(1 个亚群是细胞色素b 的两个单倍型,另1 个是控制区的两个单倍型),表明基于线粒体DNA 序列的遗
传多样性与现今基于形态特征对这些姬鼠的分类所得结果是不一致的。因此我们认为来自韩国的朝鲜亚种是一
个只在形态特异上不同于东北亚种的地方亚种,我们建议通过其他DNA 标记来进一步验证其亚种地位。我们还
认为朝鲜半岛不是最近的冰川期黑线姬鼠残遗种的保护区。     

应用线粒体 DNA 序列探讨羚牛分类地位

为探讨羚牛分类学地位,应用聚合酶链式反应(PCR)扩增了羚牛、绵羊、山羊和斑羚(青羊)线粒体DNA(mtDNA)细胞色素b基因(Cyt b gene),并测序,结合GenBank检索序列,对9种偶蹄类动物、1种奇蹄类动物Cyt b gene序列差异进行分析,构建了分子系统树(最优NJ树和唯一MP树)。通过本研究分析表明羚牛与羊亚科动物亲缘关系最近,将羚牛归入羊亚科较为合理。     

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.