云锦杜鹃ISSR扩增条件的优化

以云锦杜鹃基因组DNA为研究对象,对影响ISSR-PCR扩增效果的一些因素,包括镁离子浓度、dNTP浓度、模板DNA含量、TaqDNA聚合酶量、BSA浓度、引物用量以及退火温度等进行筛选和优化,建立了稳定、可重复的最佳反应体系:10μLPCR反应体积中,1×Taq酶配套缓冲液(10mmol/LTris.HClpH9.0,50mmol/LKCl,0.1%TritonX-100),1.5mmol/LMgCl2,0.15mmol/LdNTP,0.45UTaqDNA聚合酶,2mg/mLBSA,12pmol引物,16ng模板DNA。利用所建立的优化反应体系从100个ISSR引物中共筛选出12个稳定性好、重复性高的引物,对5个居群共100个云锦杜鹃个体的DNA进行扩增,检测到170个位点,其中多态位点150个,多态位点百分率88.24%,5个居群的多态位点百分率平均为48.23%。云锦杜鹃ISSR反应体系的建立为利用ISSR分子标记技术研究云锦杜鹃的遗传多样性奠定了良好的基础。     

濒危植物夏蜡梅ISSR扩增条件的优化

为了确保ISSR分析结果的可靠性和重复性,有必要进行ISSR-PCR反应体系的优化。以濒危植物夏蜡梅的基因组DNA为研究对象,利用单因素试验,测试了ISSR-PCR反应体系中镁离子,dNTP,模板DNA含量,Taq DNA聚合酶量、BSA浓度、引物浓度、甘油浓度等7种因素对反应结果的影响,经过优化实验,建立了夏蜡梅ISSR-PCR最佳反应体系：10 μL PCR反应体积,1×Taq酶配套缓冲液（10 mmol·L^-1 Tris·HCl pH9.0,50 mmol·L^-1 KCl, 0.1%Triton X-100）,1.5 mmol·L^-1 MgCl₂,0.75U Taq酶（上海华美公司）,20 ng模板DNA,6pmol引物（上海Sangon公司）;dATP、dCTP 、dGTP 、dTTP 各0.15 mmol·L^-1。利用优化反应体系从100个ISSR引物中共筛选出12个稳定性好、重复性高的引物,对10个居群共200个夏蜡梅个体的DNA进行扩增,共扩增出156个条带,其中多态条带为114个,总的多态位点百分率为73.08%。各居群的多态位点百分率有较大差异,平均为23.65%。夏蜡梅ISSR反应体系的建立为利用ISSR分子标记技术研究夏蜡梅的遗传多样性奠定了良好的基础。     

扎龙芦苇遗传多样性ISSR分析

采用ISSR分子标记技术对扎龙湿地的5个野生芦苇居群进行了遗传多样性研究.从75条ISSR引物中筛选出10个特异性强、稳定性好的引物进行ISSR分析.共获得96个位点,其中多态位点94个,多态位点百分率为97.92％.PopGene分析结果表明:居群的平均多态位点百分率为56.46％,Shannon's多样性指数(J)...     

紫云英ISSR引物的筛选及PCR反应体系的优化

以紫云英为研究材料,用哥伦比亚大学(UBC)公布的100条ISSR引物和11种株系紫云英品种的DNA为模板进行PCR扩增,筛选出33条扩增条带较好的ISSR引物,对其中的ISSR引物进行梯度PCR,筛选出最佳的退火温度。再采用正交试验和单因素试验相结合的方法对紫云英ISSR-PCR反应体系的5种因素(模板、Mg2+、TaqDNA聚合酶、dNTP及引物)进行优化浓度。确立了适合紫云英的ISSR分析的反应体系。在25μl反应体系中,其反应浓度为:DNA模版50.00ng,Mg2+2.00mol/L,Taq聚合酶1.0 U,dNTP 0.25mmol/L,引物0.20μmol/L,2.5μl 10×buffer。本试验为以后利用ISSR技术进行紫云英遗传多样性分析和物种保护奠定了技术基础。     

65份野生油茶种质遗传多样性的ISSR和RAPD标记分析

利用ISSR和RAPD标记,对名邛台地野生油茶种质进行遗传多样性分析。从60条简单重复序列引物中筛选出16条引物,在65份样品中共扩增出213条带,其中多态位点为203个,多态位点百分率为95.31%;从30条寡居核苷酸引物中筛选出8条引物,共扩增出105条带,其中多态性位点94个,多态位点百分率为89.52%。结果表明:名邛台地野生油茶种质具有较丰富的遗传多样性,ISSR和RAPD标记可以应用于油茶种质遗传多样性分析。     

利用ISSR揭示不同类型月季遗传多样性

本研究应用正交设计法对ISSR反应体系中的各个主要影响因子进行了优化筛选,确立了适合月季ISSR-PCR反应的最佳体系.结果表明,25μL的ISSR反应体系中各组分的最适浓度分别为:1×PCR缓冲液、1 U Taq DNA聚合酶、800 pmol/L引物、0.16 mmol/L dNTPs、Mg2+ 1.5 mmol/L.筛选了33个ISSR引物,共得到了11个多态性比较高的ISSR引物,占所筛引物的33.33%.利用筛选出的11条ISSR引物对3种月季类型的23份月季材料进行遗传多样性分析,共扩增出477条DNA带,其中多态性位点有14个,平均每条引物可以检测到4.5个多态性位点.用NTSYS软件对样品进行了UPGMA聚类分析,聚类结果表明丰花月季基本能聚为一类,切花月季与藤本月季交叉聚在一起.这表明月季种质的遗传差异与其应用分类的相关性不紧密.     

SRAP、ISSR技术的优化及在甘蓝类植物种子鉴别中的应用

将SRAP与ISSR 2种分子标记技术应用于8种甘蓝类植物（Brassica oleracea L.）的种子鉴别中。先以甘蓝（Brassica oleracea var. capitata）基因组DNA为模板,通过对SRAP、ISSR反应体系中各影响因素的逐一筛选,优化了甘蓝类植物SRAP、ISSR反应体系。进而采用30个SRAP引物组合和15个ISSR引物对白甘蓝、皱叶甘蓝、红甘蓝、羽衣甘蓝、花椰菜、青花菜、抱子甘蓝、球茎甘蓝的基因组DNA进行了PCR扩增,结果表明：M3E5与M4E5两个SRAP引物组合可以在8种甘蓝类植物之间显示较高的多态性;844和888两个ISSR引物也可在8种甘蓝类植物之间产生很好的多态,特别是844引物单独应用即可区分所有材料。     

穗花杉ISSR引物反应条件的优化与筛选

在研究穗花杉(Amentotaxus aragotaenia)的遗传多样性过程中,为了获得清晰、重复性好ISSR扩增结果,对影响ISSR-PCR的多个因素包括模板浓度、Taq酶的选择和用量、Mg²⁺和dNTPs浓度及退火温度等指标等进行了筛选和优化,确定了穗花杉ISSR-PCR分析的最适扩增条件： 20 μL PCR反应体系中,2 μL 10×Taq酶配套缓冲液,1.8 U Taq聚合酶（上海生工公司）,0.2 μmol·L^-1引物,0.18 mmol·L^-1 dNTP,1.5～2.5 mmol·L^-1 MgCl₂,10 ng·μL^-1模板DNA。用来自不同居群7个个体,以100个ISSR引物进行PCR扩增,筛选出扩增效果较好的10个引物。得到了92个位点,其中45个多态性位点,多态性位点比例为49%。     

WHBE 兔、日本大耳白兔和新西兰兔遗传多样性的 RAPD 分析

目的：应用随机引物扩增多态性DNA技术（ random amplified polymorphic DNA , RAPD）对大耳白黑眼兔（ white hair black eyes rabbit , WHBE rabbit ）、日本大耳白兔（ Japanese white rabbit , JW rabbit ）和新西兰兔（New Zealand white rabbit, NZW rabbit）3个实验兔品系进行遗传分析。方法选用90只实验兔的皮肤组织样品提取基因组DNA,用60个随机引物对实验兔基因组DNA进行PCR扩增,根据电泳结果筛选出多态性较高的引物进行RAPD-PCR分析,再利用Popgene 3．2统计软件对3个品系的扩增条带进行遗传分析,获得实验数据。结果分析结果表明：（1）60个随机引物中筛选出25个多态性较高的引物,3个品系实验兔共检测到493个扩增片段,长度在100～1800 bp之间,筛选的25个引物中,其中16个引物既可扩增出3个品系共同的DNA条带,也可扩增出WHBE兔特有的特征条带;（2） WHBE兔位点数为234个,其中多态位点数166个,多态位点比为70．94％,JW兔位点数为228个,其中多态位点数122个,多态位点比为53．51％,NZW兔位点数为231个,其中多态位点数94个,多态位点比为40．69％;（3）三个群体的Shannon多样性指数分别为0．3385,0．2222和0．1905;（4） JW兔和NZW兔的遗传相似系数最高,为0．8443,其次为WHBE兔和JW兔的遗传相似系数,为0．8204,WHBE兔和NZW兔的遗传相似系数最低,为0．7862。结论结果表明WHBE兔与JW兔和NZW兔之间有遗传的相似性,也存在着遗传差异,应用RAPD技术可以很好地检测实验兔不同品系之间以及同一品系不同个体之间的亲缘关系。     

正交设计优化绿竹ISSR-PCR体系和引物筛选

旨在建立绿竹ISSR-PCR最佳反应体系和扩增程序,并筛选适于绿竹ISSR-PCR分析的高多态性引物。以绿竹基因组DNA为ISSR-PCR扩增模板,采用正交试验方法,对d NTPs浓度、Mg2+浓度、Taq DNA聚合酶浓度、引物浓度、模板DNA用量设计5因素4水平试验,采用极差分析法和方差分析法对试验结果进行分析。并对退火温度和循环次数进行筛选,建立绿竹ISSR-PCR最佳反应体系和扩增程序。并利用优化后的体系对100条ISSR引物进行筛选。最终确定的最佳反应体系为:20μL的扩增体系中,d NTPs浓度为0.2 mmol/L,Mg~(2+)浓度为2.0 mmol/L,Taq DNA聚合酶浓度为1.5 U,引物浓度为0.4μmol/L,DNA浓度为60 ng,10×PCR Buffer体积为2μL、剩下用灭菌ddH_2O补全。各因素影响大小依次是:Mg~(2+)d NTPs模板DNATaq DNA聚合酶引物。扩增程序为:94℃预变性5 min;94℃变性45 s,(根据引物的退火温度)复性30 s,72℃延伸90 s,循环38次,72℃延伸10 min,4℃保存。以此体系为基础进行引物筛选,在100条ISSR引物中筛选出14条扩增条带清晰、多态性较高、重复性好的引物。     

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.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV