宁夏枸杞遗传多样性的RAPD分析

利用13个经筛选在样品间具多态性的10碱基随机引物,对宁夏枸杞(Lycium barbarum L.)4个主要栽培品种及3个宁夏野生枸杞的总DNA进行PCR扩增。在样品间共产生123条RAPD标记带,其中多态性带68条,多态性百分比为55.28%;以Ntsyspc2.1软件计算样品间的遗传相似系数,并进行UPGMA聚类分析。结果表明宁夏枸杞栽培品种间遗传关系较近,特别是宁杞1号和宁杞2号,相似性系数达81.82%;而野生枸杞与栽培品种间遗传关系较远。     

利用RAPD标记分析大麦种质资源的遗传多样性

利用RAPD标记对19份西藏近缘野生大麦材料、33份我国不同省市的地方品种以及8份国外引进大麦品种共60份大麦种质资源的遗传多样性进行检测.结果表明材料间遗传差异明显.32个RAPD引物中,有25个引物(占78.13%)可扩增出清晰且具多态性的条带,另外7个引物能扩增出1～3条清晰但无多态性的条带.每个引物可扩增出1～8条多态性带,平均为3.72条.32个引物共产生119条DNA片段,其中87条具有多态性,多态性比率(PPB)为73.11%,平均多态信息量(PIC)为0.434;每个位点平均有效等位基因数(Ne)为2.304;材料间遗传相似系数GS变化范围为0.757～0.981,平均值为0.871.19份来源于西藏的近缘野生大麦材料间GS值变幅为0.818～0.969,平均为0.892;33份我国栽培大麦地方品种间的GS值变化范围为0.783～0.981,平均为0.879;8份分别来自8个国家的栽培大麦品种间的GS值变幅为0.820～0.956,平均为0.882.根据RAPD标记分析的结果,对60份大麦种质资源进行聚类分析,在平均GS值0.871水平上60份大麦材料可聚为5类,聚类结果能在一定程度上反应材料的地理分布关系,但某些相同地理来源的材料也较分散地分布在整个聚类树中.本研究从分子水平上进一步证明了我国栽培大麦丰富的遗传多样性,是世界栽培大麦的遗传多样性中心之一.     

利用RAPD和ISSR标记分析烤烟品种间遗传关系

利用RAPD和ISSR标记对22份烤烟(Nicotiana tabacumL.)品种进行了遗传关系研究。在RAPD分析中筛选到13个引物,共扩增出167条带,其中多态性带50条,多态性比率为29.9%;在ISSR分析中筛选出7个引物,共扩增出96条带,其中多态性带44条,多态性比率为45.8%。两种标记相结合估算出的品种间遗传相似系数在0.881~0.979之间,平均为0.933。单独基于RAPD标记和ISSR标记的聚类结果有一定差异;两种标记结合起来的聚类分析结果与系谱信息吻合程度更高。定向选择可能对烤烟品种间遗传关系有较大影响;国外引进品种与国内育成品种并未完全分开,表明分子水平的遗传关系和地理来源间缺乏必然联系。     

香菇品种遗传多样性RAPD分子标记的研究

对32个中国栽培香菇品种和2个野生子实体的遗传多样性进行了RAPD标记研究,9个引物共扩增出113条DNA带,83.19%具有多态性。结果显示,34个香菇菌株间均有遗传上的差异,但遗传相关性极高,表明中国栽培菌株间的遗传背景单一。     

柚类种质资源RAPD标记研究的引物筛选

利用 10 0个 10碱基随机引物 ,对柚类 4个品种酸柚、沙田柚、文旦柚和泰国柚进行了RAPD标记的引物筛选研究 ,结果为无扩增产物的引物 18个 ,在 1、 2、 3个和所有 4个样品中有扩增产物的引物数分别为 2 0、 13、 2 5和 2 4个 ;读取了 12个在所有 4个样品中都有扩增产物的引物的 RAPD带 ,计算了样品间 RAPD多态性位点的百分率为 60 .6% ;计算了样品间的相似系数和遗传距离 ,并对遗传距离进行了 UPGMA聚类分析 ,论证了利用所筛选出的引物对柚类进行 RAPD标记研究的可行性和可靠性     

分子标记鉴定常山胡柚优良基因型的初步研究

本研究利用RAPD和ISSR分子标记对常山胡柚的优良基因型进行鉴定,并探讨常山胡柚的起源。从100个RAPD引物中筛选出12个多态性引物用于正式扩增,共得到117条DNA带,其中多态性DNA带64条,占扩增片段的54．7%;从105个ISSR引物中筛选出11个多态性引物用于正式扩增,共得到94条DNA带,其中多态性DNA带58条,占扩增片段的61．7%。RAPD和ISSR分析揭示了常山胡柚及其近缘种的一些特异性条带。ISSR共产生了15条特异条带,RAPD共产生12特异性条带。实验数据用AMOVA软件计算遗传距离,用NTSYS-pc软件构建UPGMA聚类树状图。结果显示,所有的基因型及不同种之间均能够彼此区分,分析得到的指纹图谱对常山胡柚种和基因型的鉴定具有潜在的应用价值,可用于优良基因型的鉴定。聚类分析结果显示常山胡柚和甜柚聚为一枝,确定了甜柚是杂交亲本之一,但是常山胡柚和柚的遗传距离较远,说明常山胡柚可能是甜橙、柚和柑桔属其他种的多重自然杂交的结果。     

鸢尾属部分植物种质资源的RAPD分析

采用RAPD分子标记技术,从100个随机引物中筛选出多态性强、重复性好且稳定性高的引物18个,对38份野生鸢尾属材料进行扩增,共扩增出409条带,其中多态性带405条,多态性比率为99.0%,表明野生鸢尾属植物种间有丰富的遗传多态性;根据DNA谱带计算物种间遗传距离,聚类分析结果将鸢尾属38份材料划分为6组,其结果与传统生物学特性划分的6个亚属的分类结果基本一致;物种特有RAPD标记分析表明,利用18个引物可以较好地将鸢尾属38种植物区分开,其中9个材料得到了单一标记的扩增带,表明运用RAPD分子标记对研究鸢尾属植物特异性基因及标记的筛选等有一定的理论和实际应用价值。     

应用RAPD指纹探讨黄麻属种间遗传多样性及其亲缘关系

采用RAPD标记构建了黄麻属(Corchorus)植物10个种27份材料的指纹图谱,从119个随机引物中筛选出清晰且多态性高的25个引物,共扩增出329条：DNA片段,分子量在0．3～3．0kb之间,其中294条谱带具有遗传多态性,多态比率(PPB)为89．36％,平均每个引物扩增出13．16条带。用Biol D^ 数据分析软件,计算Nei氏相似性系数,建立了UPCMA聚类图。结果表明：(1)供试黄麻属15份野生种和12份栽培种具有丰富的遗传多样性,遗传相似系数在0．49～0．98;(2)在聚类分析中,当L1聚值水平D=0．785时,可将两个栽培种及其近缘野生种(C．capsulris和C．olititorius)与原始黄麻野生种划分为3个不同类群。反映出栽培种及其近缘野生种与原始野生种间有明显的遗传差异;(3)当L2取值水平D=0．850时,可将供试27份材料划分为10个以物种为单元的亚类群或个类,①即假黄麻C．aestuans(3份),②三齿种C．tridens,③梭状种C．fascicularis,④假长果种C．psendo-olitorius,⑤假圆果种C．pseudo-capsularis,⑥三室种C．tilacularis,⑦甜麻(新种未定名),⑧圆果种C．capsularis(9份),⑨长果种C．olitorius(7份),⑩荨麻叶种C．uriticifolius,结果与10个种的经典分类相吻合,揭示了种间的遗传差异性。其中圆果种C．cap—sularis与长果种C．olitorius两个种亲缘关系较近,与荨麻叶种C．uriticifolius种间亲缘关系较远;(4)非洲荨麻叶种C．uriticifolius和中国的甜麻(新种)、假黄麻C．aestuans3个种与其他种间的遗传差异较大,处在分子聚类树较基础的地位,为较原始的黄麻野生种;(5)非洲的三室种21C为三室种一个生态型亚种;采集于中国的黄麻野生种河南南阳的粘粘菜、福建漳浦的麻菜,云南开远的猪菜为3个不同生态类型的假黄麻;海南野生圆果为圆果黄麻栽培种的近缘野生种;漳浦野生长果、河南野生长果、马里野生长果为长果栽培种的近缘野生种,种内不同材料间遗传相似性较高,亲缘关系较密切;(6)在两个栽培种中,品种基因型相似性系数圆果栽培种高于长果栽培种。     

应用RAFD标记研究不同生态区谷子品种的遗传差异

应用RAPD标记对19份国内不同生态区的谷子品种的遗传变异进行了研究。结果表明：分子水平上,不同生态区的谷子品种间存在一定的遗传差异,但遗传差异程度并不高。11个随机引物共扩增出54条多态性带,不同引物扩增的带数差异较大,每个引物可扩增2—8条多态性带,平均每个引物扩增出4．91条多态性带。引物1050扩增的多态性带最多(8条)。聚类结果表明,基于RAPD标记分析的遗传聚类群与生态类型有很大的一致性。     

中国狗牙根(Cynodon dactylon)优良选系的RAPD分析

对采自中国不同地区的6份狗牙根[Cynodon dactylon (L.) Pers.]优良选系进行了RAPD分子标记实验.选用15个引物共扩增出438条带,平均每个引物扩增出29条带,其中多态性带415条,多态性位点百分率达到59.02%～75.49%.各选系间遗传相似性系数差异较大(0.408～0.672),说明各选系间在DNA水平上存在着丰富的遗传多样性,与新品种C106(爬地青)相比,各选系还存在一定的改良空间.实验结果也表明,RAPD分子标记可成功地用于中国狗牙根优良选系遗传多样性的研究及品种鉴定.     

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.