栽培稻F1花粉不育基因座S—b的PCR标记定位

栽培稻 (OryzasativaL .)杂种F1花粉不育性至少由 6个基因座位所控制。为了定位其中的一个基因座位S b ,选用了 15 8个微卫星标记对粳型品种“台中 6 5”及其近等基因系TISL2之间的多态性进行了分析。结果发现第 5染色体短臂上的RM13在亲本间存在多态性。连锁分析表明 ,RM13与S b座位紧密连锁。根据微卫星标记分析的结果 ,在RGP(RiceGenomeResearchProgramofJapan)发表的遗传图谱的相应位置上选取了 11个RFLP标记 ,利用这些标记的末端序列设计特异PCR引物 ,进行ALP (ampliconlengthpolymorphism)分析 ,结果 11对引物均没有ALP。用6种四碱基识别位点的限制性内切酶进行PBR(PCR_basedRFLP)分析 ,发现由R2 2 13S和R830两克隆设计的STS(sequence_taggedsite)标记在T6 5与TISL2之间存在酶切多态性。R830STS、RM13和R2 2 13SSTS与S b座位的遗传距离分别为 3.3cM (centiMorgan)、5 .2cM和 5 .5cM。这些以PCR为基础的分子标记可以直接应用于分子标记辅助选择中 ,从而建立了基因定位与分子标记辅助选择一体化的技术体系 ,使S b座位在育种中可以得到有效的利用     

用RAPD标记对栽培稻F1花粉不育基因座S-b定位

S－b是栽培稻F1花粉不育基因座痊之一,在S－b基因座,台中65的基因型为Sj/Sj,而台中65（简称T65）的近等基因系TISL2的基因型为Si/Si,通过F2群体和BC1F1群体的遗传分析表明,台中65和TISL2的F1花粉不育性由一个基因座控制,S－b基因座的等位基因s^i和S^j相互作用,导致携带S^j基因的花败败育,产生染败花粉,用187个RFLP标记和500个RAPD引物分析 了T65和TISL2间的多态性,结果只有2个RAPD扩增片段H08－1300和Y09－H08－1300转化为RFLP标记,经F2群体的共分离分析表明,H08－1300和Y09－1500在F2群体中呈明显的偏态分离,用MAPMAKER／EXP3．0计算,H08－1300和Y09－1500与S-b基因座间的遗传 1．3cM和6．6cM,克隆和测定了H08－1300两侧的部分DNA序列,经同源性分析发现,右末端580bp的序列中有101bp 的序列与水稻第五染色体的克隆P0033D06（注册号：AC079357）有94％的同源性,左末端中540bp的序列中P0033D06有86％的同源性,由于P0033D06为由位于水稻第五染色体定位18．8cM处的标记R3166锚定,结果说明S－b基因座位于水稻第五染色体上,与R3166的遗传距离为1．3cM,同时还讨论了对于应用基因组测序的结果进行RAPD标记染色体定位的方法。     

利用分子标记辅助选择改良珍汕97的稻瘟病抗性

利用回交育种中产生的回交群体,结合前人的研究结果构建了Pil基因区域的局部分子标记连锁图,通过BC1F2家系的接种结果判断其基因型.将Pi1定位在RFLP标记RZ536与SSR标记RM144之间,图距分别为9.7cM、6.8 cM,从而建立了一套完整的以PCR为基础的分子标记辅助选择体系.通过分子标记和抗性验证两种选择方式相结合,经过三代回交将Pi1区段快速导入受体亲本珍汕97B中.在BC3F1中利用15条ISSR引物扩增的167条随机分布在基因组中的多态性带筛选背景,得到4个背景较好的单株.经过纯合筛选及抗性验证后共得到17个带有抗性基因Pi1的改良珍汕97株系.试验表明微卫星标记在正向选择、负向选择及背景选择中都起到极大的作用.     

利用分子标记辅助选择改良珍汕97的稻瘟病抗性

利用回交育种中产生的回交群体，结合前人的研究结果构建了Pi1基因区域的局部分子标记连锁图，通过BC1F2家系的接种结果判断其基因型。将Pi1定位在RFLP标记RZ536与SSR标记RM144之间，图距分别为9．7cM、6．8cM，从而建立了一套完整的以PCR为基础的分子标记辅助选择体系。通过分子标记和抗性验证两种选择方式相结合，经过三代回交将Pi1区段快速导入受体亲本珍汕97B中。在BC3F1中利用15条ISSR引物扩增的167条随机分布在基因组中的多态性带筛选背景，得到4个背景较好的单株。经过纯合筛选及抗性验证后共得到17个带有抗性基因Pi1的改良珍汕97株系。试验表明微卫星标记在正向选择、负向选择及背景选择中都起到极大的作用。     

栽培稻F_1花粉不育基因座S-α的分子定位

以栽培稻品种台中65及其等基因已不育系TISL4为材料,用RFLP和RAPD等技术,对F_1花粉不育基因座S－a定位。通过用RFLP和RAPD方法对亲本间进行多态性分析,发现亲本间的多态性很低,说明经多代回交后,在等基因系基因组中供体亲本的DNA片段所占的比例很小。通过连锁分析,将S－a定位在第1染色体上。S－a与分子标记CDO548、O11—1000、RG146和Y13－500之间的遗传距离分别为6.4cM、6.8cM、7.2cM和11.3cM。S－a基因座上S－a~i／S-a~j等位基因互作使携带S-a~j基因的花粉败育是寻致该F_2群体产生偏态分离的主要原因。     

磁珠富集法分离刀鲚微卫星标记

利用磁珠富集法分离微卫星序列,以开发长江刀鲚微卫星分子标记。将长江刀鲚基因组DNA经限制内切酶Mse I酶切,回收400-1 000 bp片段,安装接头,构建长江刀鲚全基因组PCR文库。用生物素标记的微卫星探针(CA)12与其杂交,磁珠富集含有微卫星序列的DNA片段。将洗脱所得片段进行PCR扩增,然后进行克隆。经过菌落PCR检验后挑选出118个阳性克隆进行测序,其中97条含有微卫星序列。用设计合成59对微卫星引物对30尾养殖长江刀鲚进行引物的多态性筛选,得到9对多态性引物。     

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。     

伊犁鲈微卫星位点的筛选及近缘物种通用性

为开发伊犁鲈(Perca schrenkii)分子标记用于鲈属鱼类种质资源保护,以伊犁鲈为材料,应用磁珠富集法进行了微卫星标记的筛选.从伊犁鲈尾鳍提取总DNA,进行酶切、接头连接、PCR扩增,再采用生物素标记(CA)15探针及生物素标记(TG)15探针对扩增产物进行杂交富集,经再次PCR扩增及T-A克隆,成功构建了伊犁鲈基因组微卫星富集文库.采用重复序列引物筛选获得阳性克隆,随机选取48个阳性克隆进行测序,测得序列46个,其中38个克隆含有微卫星序列,41个位点的微卫星重复数在8次以上.根据测得序列设计17对微卫星引物,均能在伊犁鲈群体中扩增获得目的条带.采用该17对引物对河鲈(P.fluviatilis)及黄金鲈(P.flavescens)群体样本进行扩增,10对引物具有通用性,其中6对在河鲈中具有高度多态性(PIC>0.5),5对在黄金鲈中具有高度多态性.     

微卫星位点获取方法的研究进展

微卫星标记(simple sequence repeat,SSR)是进行分子遗传学研究的一种有效手段,并以其多态性高、信息含量大、保守性等特点成为最受人们欢迎的分子标记之一.但微卫星标记具有种族特异性,必须采用特异引物进行PCR检测,因而存在引物开发的问题.本文就筛选基因组文库法、微卫星富集法、数据库查找法、近缘物种筛选法、TOMMI法和FI-ASCO法等具有代表性的微卫星标记开发策略进行了综述,旨在为分子生态学研究过程中微卫星位点筛选方法的选择提供参考.     

家养水牛30个微卫星标记的多重PCR体系建立及其多态性检测

利用变性聚丙烯酰胺凝胶电泳结合硝酸银染色方法, 从30个微卫星标记中筛选出9组多重PCR体系, 其中4组三座位组合, 5组二座位组合; 在此基础上进一步检测了这些标记在中国海南兴隆水牛中的遗传变异性。结果显示其中26个标记具有多态性, 而其余4个标记(CSSM045, ILSTS008, RM099和HMH1R)为单态, 群体平均等位基因数4.7, 平均期望杂合度为0.534。所筛选出的多重PCR组合为家养水牛的群体遗传多样性 检测和亲子鉴定等研究提供了技术基础。     

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