分子标记技术的发展及应用

介绍了几种应用前景较广的分子标记,如基于DNA杂交技术的分子标记:限制性片段长度多态性(RFLP)和DNA可变串联重复数标记(VNRT);基于PCR技术的分子标记:随机扩增多态性 DNA(RAPD)、酶切扩增多态性(CAPS)、扩增片段长度多态性(AFLP)、微卫星DNA(SSR)和DNA单链构象多态性(SSCP);以及新兴的第3代分子标记,即基于DNA芯片技术的分子标记:单核苷酸多态性(SNP)等。分别阐述了它们的原理、方法步骤与优缺点、应用注意事项和适用范围,同时概述了它们在生物学研究中的应用和进展。     

扩增片段长度多态性( AFLP) ——一种新的分子标记技术

AFLP(扩增性片段长度多态性)是一种新的DNA分子标记。与RFLP、RAPD相比,AFLP具有在一次试验中可同时观察到大量的限制性片段的优点。本文阐述了AFLP的原理和方法,综述了AFLP目前在植物遗传育种研究中的应用进展,并对AFLP技术在植物遗传育种中的应用前景提出了初步设想。     

几种分子标记方法相结合建立的新型分子标记方法

介绍了几种分子标记相结合,产生的分子标记新方法的基本原理、优缺点,如AFLP、SCAR、CAPS以及RMAPD分子标记。其中主要介绍了RMAPD,对RMAPD作为一种新型分子标记进行探讨。     

中国兰花资源分子标记鉴定研究进展

系统阐述了RAPD、SSR、RFLP、AFLP和其它几类分子标记在中国兰花种质资源鉴定及遗传多样性研究中的应用进展。同时指出,应用分子标记研究兰属植物的遗传多样性对兰属的科学分类及新品种选育等具有指导意义,并提出展望。     

AFLP分子标记技术在昆虫学研究中的应用

AFLP分子标记技术是一种建立在PCR技术和RFLP标记基础上的新的DNA指纹分析技术 ,具有多态性丰富、结果稳定可靠、重复性好、所需DNA量少、可以在不知道基因组序列的情况下进行研究等特点 ,现已广泛用于构建遗传图谱、遗传多样性研究、系统进化及分类学、遗传育种和品质鉴定以及基因定位等方面。该文介绍了AFLP标记技术的原理以及在昆虫学研究中的应用。     

分子标记及其在海洋动物遗传研究中的应用

分子遗传标记在农业动植物育种和生产上得到了广泛的应用,且取得了可喜的成果,但在水生生物上的应用还处于初始阶段。本文简要介绍了限制性片段长度多态性（RFLP）、随机扩增多态性DNA（RAPD）、扩增片段长度多态性（AFLP）、小卫星DNA和微卫星DNA（或称简单序列重复,SSR）等分子标记的概念、基本原理及其特点,重点介绍了第三代分子标记单核苷酸多态性（SNP）技术。综述了这些分子标记在海洋动物遗传结构分析、亲缘关系鉴定、遗传图谱的构建和标记辅助育种等方面的应用。     

AFLP标记在研究家蚕遗传多态性方面的应用

AFLP是一种多态检出效率很高的分子标记技术,在构建遗传图谱,遗传多态性研究,重建分子系统演化树,品种鉴定,基因克隆等众多研究领域有着其它分子标记技术不可比拟的优势。本文在前人用AFLP技术对植物多态性研究的基础上,将AFLP用于家蚕的遗传多态性研究,结果发现在家蚕中同样具有丰富的AFLP标记的多态性。由此暗示AFLP技术亦适合研究家蚕等昆虫类动物的遗传多态性,构建遗传图谱,或用于其分子生态学,分子进化和分类等方面的研究。此外本文还探讨了适合于家蚕等昆虫的AFLP分析的实验条件。     

分子标记在啤酒花种质资源研究中的应用

该论文利用分子生物学中常用的DNA分子标记对世界各地现存的野生和栽培的啤酒花种质资源遗传多样性研究的应用进展做一综述。通过查阅和研读20世纪90年代以来发表的各类文献进行归纳总结。发现DNA分子标记相比形态学标记和细胞学标记具有结果准确、稳定的特点,常用的分子标记技术有RAPD、RFLP、ISSR、SSR、AFLP、EST等;研究发现北美洲的啤酒花遗传多样性要高于欧洲的啤酒花,基因变异程度也相对较高;野生啤酒花的基因序列具有丰富的基因多样性,可在分子杂交遗传育种中作为一个种质去改善栽培品种的某些不良性状。因此,利用分子标记研究啤酒花的遗传多样性将对啤酒花的优良育种提供理论指导和技术支持,目前较为理想的技术是SSR和AFLP。     

AFLP标记的特点及其在昆虫学研究中的应用

扩增片段长度多态性（AFLP）是一种新兴的很有效的分子遗传标记方法, 它通过对基因组DNA限制性内切酶酶切片段进行选择性扩增而揭示多态性,具有快速、经济简便、不需要预先知道模板DNA的信息、模板需要量少、重复性高、结果可靠及具有很高的信息含量等优点。AFLP也具有缺点,主要是标记是显性的,同其他显性标记一样,不能区分杂合体和纯合体,因而不能更好地估算种群遗传的变异,对种群遗传结构的分析不能提供更多的统计信息;AFLP技术较复杂,而且经常使用放射性同位素,对模板DNA质量要求也较高。为了克服AFLP的这些缺点,人们又在其基础上发展了其他相关技术,例如AFRP、SAMPL、DALP和TE-AFLP等。目前AFLP在昆虫方面的应用还不是很多,处于初级阶段,主要应用在生态型鉴定、种群遗传分析、连锁图谱构建等方面,相信随着其技术的发展完善,必将会越来越多地应用于昆虫学的研究中。     

AFLP 分子标记技术的发展

AFLP分子标记技术是一种建立在PCR技术和RFLP标记基础上的新的DNA指纹分析技术,具有多态性丰富、结果稳定可靠、重复性好、所需DNA量少,且可以在不知道基因组序列的情况下进行研究等特点,现已被广泛用于构建遗传图谱、遗传多样性研究、系统进化及分类学、遗传育种和品质鉴定以及基因定位等方面。介绍AFLP技术的原理以及AFLP技术基础上条件的改进。     

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