新疆3种雅罗鱼线粒体DNA细胞色素b序列的差异与系统进化

利用鲤科鱼类线粒体DNA细胞色素b通用引物对分布在新疆的准噶尔雅罗鱼(Leuciscusmerzbacheri)、贝加尔雅罗鱼(L .baicalensis)和高体雅罗鱼(L .idus) 3个鱼种共1 5尾个体的线粒体DNACytb部分核苷酸序列进行了测定,获得1 5条长度为41 3bp的同源基因序列。同源基因序列分析显示,在3种雅罗鱼1 5条mtDNACytb基因片段中,A、T、C、G碱基的平均含量分别是:2 7 4%、2 6 7%、1 7 2 %、2 8 7% ,其中A T含量(5 4 1 % )高于G C含量(4 5 9% ) ;共检测到5 2个突变位点;转换比颠换发生频率高,转换颠换比值(R)是3 5。mtDNACytb的进化速率在3种雅罗鱼间表现出不一致性,贝加尔与高体雅罗鱼、贝加尔与准噶尔雅罗鱼种间遗传距离分别是0 1 2 5 1和0 1 2 61 ,保守性较低;高体与准噶尔雅罗鱼种间的遗传距离是0 0 0 0 7,高度保守。mtDNACytb分子系统树显示,在3种雅罗鱼中贝加尔雅罗鱼独立成一枝,高体雅罗鱼和准噶尔雅罗鱼聚成一类。提示了,在mtDNACytb分子水平上,高体雅罗鱼和准噶尔雅罗鱼的亲缘关系十分相近,贝加尔雅罗鱼与准噶尔雅罗鱼的亲缘关系相距较远。我们对准噶尔、贝加尔和高体雅罗鱼mtDNACytb方面的研究与陈星玉对其骨骼类型的研究结果相吻合。     

新疆三种雅罗鱼属鱼类mtDNA D-loop多态性及起源分化分析

用PCR-RFLP技术,对新疆分布的准噶尔雅罗鱼、贝加尔雅罗鱼和高体雅罗鱼的mtDNA D-loop高变区约827bp进行了扩增,用ScaI、HinfI、AluI、DdeI 4种限制性内切核酸酶对56个样本的扩增产物酶切和RFLP分析,共检测到6种单倍型。准噶尔雅罗鱼存在2种单倍型：BDAA和BDBA;贝加尔雅罗鱼存在3种：AAAA、ABAA和ACAA;高体雅罗鱼只有1种。初步认为,准噶尔雅罗鱼、贝加尔雅罗鱼存在较丰富的群体内变异。用6种单倍型及净遗传距离绘制的UPGMA分子系统树,提示准噶尔雅罗鱼有可能是原始种,贝加尔雅罗鱼和高体雅罗鱼是由准噶尔雅罗鱼进化而来。 Abstract:PCR-RFLP technique was employed to amplify about 827bp of mtDNA D-loop hypervariable region of Leuciscus baicalensis,L.merzbacheri and L.idus in Xinjiang.The PCR products of 56 samples with four restriction enzymes were digested:ScaI,HinfI,AluI,DdeI,and RFLP analysis was done then.The study indicates that all of L. species and populations have six haplotypes,L.merzbacheri has two haplotypes:BDAA,BDBA;L.baicalensis has three:AAAA,ABAA,ACAA;L.idus has one:CAAA.It is primarily considered that L.merzbacheri and L.baicalensis have more intra-population mutations.The UPGMA trees with 6 haplotypes and net genetics distance pointed out that L.merzbacheri might be original species,L.baicalensis and L.idus are evolved from L.merzbacheri.     

基于线粒体Cyt b序列对新疆额尔齐斯河贝加尔雅罗鱼遗传结构的分析

采用线粒体Cyt b基因序列对额尔齐斯河流域的青河(QH,18尾)、哈巴河(HBH,21尾)、185团(185T,18尾)和乌伦古湖(WLG,20尾)4个贝加尔雅罗鱼(Leuciscus leuciscus baicalensis)群体进行了遗传结构的比较分析。在片段长度为1 109 bp的同源序列上,77尾个体共检测到54种单倍型,其中共享单倍型7个,总单倍型多样性指数(Hd)、总核苷酸多样性指数(π)和平均核苷酸差异数(K)分别为0.981 9、0.008 21和9.091,且185团群体单倍型多样性指数和核苷酸多样性指数最高、青河群体最低。4个群体间遗传距离在0.006~0.011之间,基于Kimura 2-parameter法构建的单倍型邻接关系树分为3支,群体间遗传关系和地理分布没有明显的相关性。AMOVA分析显示额尔齐斯河流域贝加尔雅罗鱼遗传差异极显著(P0.01)。青河和乌伦古湖群体基因流(Nm)远高于其他群体间,推测乌伦古河或许是二者进行基因交流的渠道。尽管单倍型核苷酸不配对分布呈双峰,但偏差平方和(Q)与粗糙指数(r)均不显著(P0.05),且Tajima′s D和Fu′s Fs检验也均显著偏离中性,结合群体呈现高单倍型多样性和低核苷酸多样性的特点,推测贝加尔雅罗鱼经历了群体扩张事件。参考已校正的鲤科鱼类Cyt b基因0.76%/Ma的进化速率,估算群体扩张的时间大约在1.97 Ma前的更新世中晚期,推测该时期阿尔泰山地区发生的冰川作用和频繁的古地震造成的地理隔离和融合可能是贝加尔雅罗鱼发生群体扩张的重要原因。     

基于线粒体控制区序列的黄河上游厚唇裸重唇鱼种群遗传结构

采集黄河上游厚唇裸重唇鱼(Gymnodiptychus pachycheilus)甘肃玛曲群体,测定其线粒体DNA控制区序列,并从GenBank中下载青海玛多和贵德等3地2个群体的同源序列,分析该物种的遗传多样性、遗传结构及其演化历史.从81条729 bp序列中,检测到26个变异位点(占3.57％),碱基序列总的单倍型多样性为0.844,核苷酸多样性为0.0054,界定了34个单倍型,有1个广布单倍型H2,占所有样品的38.27％.单倍型网络图图显示单倍型没有明显的亲缘地理格局,H2处于中心,呈星状发散,系统发育分析没有显示出单倍型与地理位置的对应关系.AMOVA分析显示变异主要来自地理区内群体间,歧点分布和中性检测显示厚唇裸重唇鱼近期经历了种群扩张.分析表明黄河上游3地种厚唇裸重唇鱼种群未出现分化,建议应作为一个整体进行保护.     

红鲫部分线粒体DNA序列变异分析

对红鲫19尾个体的线粒体tRNA-Thr基因、tRNA-Pro基因和部分控制区的核苷酸序列进行了测定．获得19条长度为836～837bp的同源基因序列,共发现18个变异位点．定义了4种单元型．在红鲫4种单元型中确认了DNA复制终止相关的序列TAS、中央保守区序列（CSB-F、CSB-E和CSB-D）和保守序列CSB1．在18个变异位点中,除一个缺失外,序列变异全部为转换,无颠换发生．4种单元型之间的序列差异在0．1％。1．7％之间．结果显示,红鲫群体具有较高的遗传多样性水平,因而暗示了它具有较强的适应外界环境变化的能力,同时说明它是鱼类遗传育种的较好实验材料．     

美丽硬仆骨舌鱼mtDNA D-loop区遗传变异特征

采用直接测序法分析美丽硬仆骨舌鱼(Scleropages formosus)3个种群(金龙鱼、红龙鱼和青龙鱼)共24个个体的线粒体D-loop区的遗传变异特征。经序列比对、分析,金龙鱼、红龙鱼和青龙鱼的D-loop序列不仅在个体间存在位点序列的变异(17个简约性信息位点),而且还存在序列长度的多态性(长度为915-924 bp),这种长度的差异在于存在不同碱基长度的微卫星序列。3种龙鱼碱基组成基本一致,G含量偏低。定义了10种单倍型,但金龙鱼、红龙鱼和青龙鱼间没有共享单倍型,单倍型多样度较高(0.667-1.00),核苷酸多样度较低(0.001 09-0.003 23)。AMOVA分析显示,变异主要来自地理区内不同群体间,个体间遗传距离为0-0.008 7,显示遗传变异仍处于种内水平。NJ、MP和Bayesian构建的分子系统树拓扑结构基本一致,但不能有效地反映金龙鱼、红龙鱼和青龙鱼间的亲缘关系。     

基于线粒体Cyt b基因序列变异的克孜河塔里木裂腹鱼和斑重唇鱼遗传多样性

采用线粒体细胞色素b基因(Cyt b)序列,分析了采自新疆克孜河3个群体(斯木哈纳SM、牙师YS、卡拉贝利KL)的塔里木裂腹鱼(Schizothorax biddulphi)41尾个体及1个斑重唇鱼(Diptychus maculates)群体(斯木哈纳)23尾个体的种群遗传多样性和遗传结构.结果显示,塔里木裂腹鱼检测到6个碱基变异位点,定义了4种单倍型,平均单倍型多样性指数及核苷酸多样性指数分别为0.525 4和0.001 16.分子变异分析(AMOVA)结果提示,塔里木裂腹鱼的遗传变异全部发生于群体内部;群体间Kimura-2-parameter遗传距离、分化指数(F<,st><0.085 25)和基因流(N<,m>>3.18)都显示3个群体没有种群分化,属于单一种群.斑重唇鱼检测出7个变异位点,定义了8个单倍型,平均单倍型多样性指数与核苷酸多样性指数分别为0.830 1和0.001 13.研究表明,克孜河的塔里木裂腹鱼和斑重唇鱼均处于很低的遗传多样性水平,物种维持力较弱.     

云南猕猴mtDNA控制区全序列测定

目的测定云南猕猴线粒体DNA控制区全序列,对其进行鉴定及进化分析。方法利用PCR技术扩增猕猴线粒体DNA控制区全序列,结合GenBank中下载的猕猴参考序列（AY612638）,采用多个生物学软件对序列碱基组成、同源性、转换／颠换比等遗传信息进行分析,并基于邻接法（NJ）和最小进化法（ME）构建系统进化树。结果云南猕猴线粒体DNA控制区全长为（1084-1089）bp,A、T、G和c四种碱基平均含量分别为29．9％、26．9％、12．3％和30．9％,A＋T含量（56．8％）高于G＋C含量（43．2％）。所分析序列间的同源性为91．5％-99．5％,平均核苷酸变异率为4．5％,变异类型包括转换、颠换、插入和缺失4种形式,转换／颠换比值平均为26．1。进化树显示云南猕猴存在两个平行进化的姐妹分支。结论本研究获得了云南猕猴mtDNA控制区全序列,为猕猴进化关系研究及mtDNA控制区功能研究奠定基础。     

准噶尔雅罗鱼β-肌动蛋白基因启动子克隆及序列分析

利用PCR方法克隆了准噶尔雅罗鱼(Leuciscus merzbacheri)的β-actin基因启动子片段SZ21,大小是2398bp。对克隆的启动子序列进行了转录调控元件的生物信息学预测分析,同时,基于启动子中包含的开放阅读框和内含子序列,探讨了准噶尔雅罗鱼与鲤鱼(Cyprinus carpio)、草鱼(Ctenopharyngodon idella)、青鱼(Mylopharyngodon piceus)、团头鲂(Megalobrama amblycephala)、泥鳅(Misgurnus mizolepis)间的系统进化关系。结果显示,该启动子序列的3个核心启动子转录元件:CAAT-box、CArGmotif和TATA-box分别在转录起始位点(+1)上游的-89、-59、-26处,序列中还含有MEF2、SATB、CHRF、INRE、MTEN、E-box、RU49、ZBPF、CREB、Enhance region、CEBP位点等多种转录调控元件。在剪接体内含子中,剪接位点遵循GT…AG法则。启动子SZ21序列含有3个内含子和155个氨基酸。内含子1、内含子2、内含子3的系统发育分析表明,团头鲂与草鱼和青鱼的亲缘关系要比与准噶尔雅罗鱼的更近一些,这与传统分类中的亲缘关系显示不一致,其原因尚需探讨。     

长江中上游银[鱼句]线粒体DNA遗传多样性分析

银[鱼句]（Squalidus argentatus）是长江常见小型鱼类,分布广泛于干支流,资源量较大。本研究采用线粒体DNA（mtDNA）细胞色素b基因序列对长江中上游干流江津、荆州、监利、洪湖、黄石江段及支流赤水河、湘江等7个江段共217尾银[鱼句]样品的遗传结构和遗传多样性进行了分析。结果显示,银[鱼句]群体Cyt b基因序列分别检出了81个变异位点和97个单倍型,平均单倍型多样性（Hd）和核苷酸多样性（Pi）分别为0.966和0.008 6。分子方差分析（AMOVA）显示,长江中上游银[鱼句]群体存在显著遗传分化。群体间两两比较分析发现,赤水河群体与其他群体基因交流程度低,遗传分化显著,其他群体间没有显著遗传分化。中性检验结果不支持银 历史上发生过群体扩张。     

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.