大麻性别的RAPD和SCAR分子标记

利用随机扩增多态性DNA(randomamplifiedpolymorphicDNA,RAPD)技术获得与大麻性别连锁的分子标记.将10株雄性大麻或10株雌性大麻的单个DNA样品等量混合分别组成雄性或雌性DNA池(DNApool),以提供具有相同遗传背景的雌、雄性DNA样品.每个随机引物分别用三个不同的循环程序进行PCR扩增.在30个随机引物中,用引物401扩增得到一条约2.5kb雄性多态性片段.对该片段进行了克隆和序列分析,并根据序列分析结果将上述RAPD分子标记转化为重复性和特异性更好的SCAR(sequencecharacterizedamplifiedregions)分子标记.     

巨型引物PCR法对抗CD3改型单链抗体

亲和力是影响改型单链抗体应用于临床的重要因素之一.利用巨型引物PCR定点诱变方法,设计并化学合成出两组含多个突变位点的简并引物,在第一轮PCR中使用简并引物分别扩增出含突变碱基的两条特异性的DNA片段,即巨型引物,将其经琼脂糖凝胶电泳分离纯化后,作为3′和5′的两端引物应用于第二轮PCR反应中.通过改变标准PCR反应条件,调整引物与模板的浓度,扩增出特异性较强的目的DNA条带.PCR产物经回收后,进行DNA测序.测序结果表明利用该方法扩增得到特异的抗CD3改型单链抗体的突变体库.     

白鲢和鳙鱼的随机扩增多态DNA分析

根据鱼类外周血细胞都有核的特点,采用从冷冻和低渗双重处理分离的细胞核提取基因组DNA.以此法获得的白鲢和鳙鱼的基因组DNA为模板,和Operon公司生产的OPN和OPM两个组共40个随机引物,对这两种鱼进行了随机扩增多态DNA(RAPD)分析;确定了对这两种鱼基因组相关区域可进行随机PCR扩增的有效引物,特别是哪些可产生种群内或群体的RAPD遗传标记,即可产生个体特异性和群体特异性RAPD带谱的引物.讨论了RAPD遗传分子标记在鱼类遗传,特别是遗传多样性研究,和鱼类种质资源评估和管理中的应用前景问题.     

大麻性别的RAPD和SCAR分子标记

利用随机扩增多态性DNA（random amplified polymorphic DNA,RAPD)技术获得与大麻性别连锁的分子标记,将10株雄性大麻或10株雌性麻的单个DNA样品等量混合分别组成雄性或雌性DNA池（DNApool),以提供具有相同遗传背景的雄,雄性DNA样品。每个随机引物分别用三个不同的循环程序进行PCR扩增,在30个随机引物中,用引物S401扩增得到一条约2．5kb雄性多态性片段,对该片段进行了克隆和序列分析 ,并根据序列分析结果将上述RAPD分子标记转化为重复性和特异性更好的SCAR（Sequence characterized amplified regions)分子标记。     

一种新的分子标记方法－随机微卫星扩增多态DNA (RMAPD)

随机微卫星扩增多态DNA（RMAPD）是利用随机引物和微卫星的上游或下游引物一起作为该扩增的引物,在Taq DNA聚合酶、MgCl2、dNTPs和模板DNA等共同作用下进行PCR扩增的一种新型分子标记方法。其核心是RMAPD引物的有效性问题。通过对西农萨能奶山羊群体RMAPD电泳检测、数据统计分析及验证实验等证明RMAPD的引物是有效的。通过与微卫星和RAPD标记比较,发现RMAPD标记在扩增引物、扩增程序和重复性等方面区别于微卫星和RAPD标记;它是RAPD标记的一种广义的延伸,但又不完全等同于RAPD标记。因此,确定RMAPD是一种新的分子标记方法。该方法也具有DNA标记的特点,在群体遗传结构和亲缘关系分析以及标记辅助选择等遗传育种领域具有广阔的应用前景。     

利用聚合酶链反应扩增基因片段

聚合酶链反应(PCR)是一种模拟天然DNA复制过程的核酸扩增法,具有敏感特异、产率高、操作简单、容易自动化等特点。由于它有成指数倍(2~n)扩增靶序列的能力,又被称之为“无细胞分子克隆”或“试管内分子克隆”。我们以化学合成的寡核苷酸的粗提物为引物,含目的基因片段的重组质粒DNA为模板,利用PCR技术成功地扩增出数百至3544bp的特异性     

多聚酶链反应——方法和仪器

<正>多聚酶链反应(PCR)类似体内DNA复制过程,在待扩增的“靶”或“模板”DNA双链分子的的两端各接一个引物,经一次循环后,可得到两个相同的双链靶DNA分子。DNA分子数随循环次数呈几何级数增长,30次循环后,靶DNA被放大2~(30)倍,其拷贝数可达10~9以上,在100ul PCB反应混合物中约产生2～3μ DNA。扩增的靶DNA分子长达10～18kb,但4kb抗更短的靶DNA最适宜PCR扩增,PCR能测出10~6基因组中的一个DNA拷贝。     

绿僵菌M189菌株特异性SCAR标记的建立及田间监测应用

为了监测生防真菌绿僵菌菌株在田间释放后的回收,有必要建立菌株DNA分子标记,以此将应用的菌株与其他菌株或田间的土著分离株鉴别开来。作者采用16条随机引物扩增了51株绿僵菌菌株的基因组DNA,得到81个多态性位点。其中M189菌株多态性位点30个,分析得到1个特异性位点,并将该位点的DNA片段测序后转化成为特异性SCAR标记。检验确定了该标记的敏感性,可以从供试的51株菌株中准确鉴定出目的菌株M189。并用该标记检测了从田间回收的3个分离株,确定其中1个与应用菌株M189一致。     

InDel标记的研究和应用进展

InDel是指在近缘种或同一物种不同个体之间基因组同一位点的序列发生不同大小核苷酸片段的插入或缺失(insertion-deletion), 是同源序列比对产生空位(gap)的现象。InDel在基因组中分布广泛、密度大、数目众多。InDel多态性分子标记是基于插入/缺失位点两侧的序列设计特异引物进行PCR扩增的标记, 其本质仍属于长度多态性标记, 可利用便捷的电泳平台进行分型。InDel标记准确性高、稳定性好, 避免了由于特异性和复杂性导致的后续分析模糊。此外, InDel标记能扩增混合DNA样品和高度降解的微量DNA样品, 并进行有效分型。InDel标记目前已开始应用于动植物群体遗传分析、分子辅助育种以及人类法医遗传学、医学诊断等领域。随着位于功能基因上InDel标记的开发, 结合染色体步移和基因精细定位, 可将这些标记应用于相关物种经济性状的功能基因的筛选, 有利于优良基因的进一步开发和利用。     

基于RNA-seq数据的窄足真蚋SSR分子标记开发

【目的】窄足真蚋Simulium(Eusimulium)angustipes属嗜血蚋种,并传播禽类疾病。本研究旨在通过RNA-seq技术获得窄足真蚋的转录组数据,进而开发其微卫星标记,为窄足真蚋的种群遗传学研究提供可靠的分子标记。【方法】以采自陕西宝鸡和新疆阿勒泰地区的窄足真蚋幼虫为材料,构建转录组数据库。使用软件MISA(microsatellite identification tool)搜索窄足真蚋unigenes库中的所有SSR位点,并随机挑选SSR位点,利用软件Primer Premier 5.0和Oligo 6.7设计微卫星引物。经PCR扩增和电泳检测,用Cervus 3.0.7等生物信息学软件进行统计分析,筛选多态性微卫星引物。利用Blast X比对Nr和Swiss-Prot蛋白质数据库,对含多态性SSR位点的unigenes进行功能注释。【结果】共鉴定出29 471个SSRs。最丰富的重复基序是单核苷酸重复类型,占总SSR数的87.05%;其次是三核苷酸重复类型,占7.95%。共发现34种碱基重复基序,主要是A/T基序重复,占86.93%。15对微卫星引物均成功扩增出特异性产物,含12对具多态性的微卫星分子标记。比对结果显示,7个SSR位点来自注释基因序列。【结论】基于RNA-seq二代测序技术可实现窄足真蚋SSR分子标记的高效率开发,对窄足真蚋的种群遗传学研究具有重要意义。     

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