辣椒多聚半乳糖醛酸酶基因CaPG的克隆与序列分析

以耐贮辣椒品系P98为材料,采用RACE方法,首次获得辣椒果实多聚半乳糖醛酶(PG)基因的全长cDNA,命名为CaPG,登录号为FJ596175.序列分析结果表明,该基因cDNA长1 668 bp,5′非编码区为119 bp,3′非编码区为442 bp,CDS长1 107 bp,编码368个氨基酸.Blast比对发现,该基因核苷酸序列与已报道的番茄和番木瓜PG基因具有84%和85%的相似性.聚类分析表明,该基因与番茄和番木瓜的亲缘关系较近,与拟南芥PG基因的亲缘关系较远.     

白桦肌动蛋白(Actin)基因全长cDNA克隆与序列分析

以白桦(Betula platyphylla Suk.)次生木质部为材料,用改良CTAB方法提取总RNA。根据植物肌动蛋白(Actin)基因编码区的保守序列设计引物后进行RT-PCR,并采用RACE技术扩增出Actin基因全长序列。该基因cDNA全长1 785 bp,序列分析表明,该基因编码区1 134 bp,编码377个氨基酸,5′非编码区157 bp,3′非编码区495 bp。所得序列与GenBank中注册的其它植物肌动蛋白核苷酸序列的相似性均在80%以上,氨基酸序列的相似性高达96%以上。此基因已在GenBank注册（EU588981）。根据高等植物肌动蛋白相似性构建了进化树,表明白桦肌动蛋白与蓖麻肌动蛋白之间的亲缘关系最为密切,在进化中分化时间最为接近。     

人脑红蛋白(NGB)全长cDNA序列的克隆

人脑红蛋白(neuroglobin, NGB)是新发现的神经系统特异的携氧蛋白, 然而其全长cDNA序列一直未见报道. 采用电子序列延伸技术和cDNA序列末端快速扩增技术(rapid amplification of cDNA ends, RACE)研究发现, 人NGB全长cDNA序列为1 909 bp, 5′非编码区为375 bp, 编码区(456 bp)可编码151个氨基酸, 3′非编码区为1 078 bp, 其中含27 bp的poly(A)(GenBank接受号: AF422797). 综合采用电子序列延伸技术与RACE技术是获得全长cDNA序列的有效方法, 为后续的功能研究提供了重要基础.     

牡丹开花相关基因PsAP1的克隆与表达

APETALA1基因对花器官的形成具有重要作用,并且能够调节花期.以牡丹品种赵粉(Paeoniasuffru-ticosaL.cv.Zhaofen)为试材,采用RT-PCR和RACE方法从花瓣中获得了1个牡丹APETALA1基因cDNA全长,命名为PsAP1,GenBank登录号为HM143943.其cDNA全长1103 bp,包含130 bp的5′非编码区、244 bp的3′非编码区和1个长度为729 bp编码242个氨基酸的开放阅读框.序列比对和系统进化分析表明,PsAP1与葡萄的亲缘关系最近,相似性达80%以上,属于MADS家族AP1/SQUA亚家族.相对荧光定量PCR分析表明,PsAP1在花瓣中的表达量最高,在雄蕊中表达量最低.     

珊瑚藻R-藻红蛋白γ亚基基因的克隆(英文)

根据珊瑚藻(Corallina afficinalis L.)R-藻红蛋白γ亚基N末端部分氨基酸序列(P83592)设计简并引物,结合RACE方法,扩增获得g亚基的全长cDNA序列。结果表明,序列全长为2308 bp(AY209894),5′非编码区长1203bp,3′非编码区长145 bp,编码区长960 bp,编码320个氨基酸组成的前体,包含71个氨基酸构成的信号肽和249个氨基酸组成的成熟蛋白。成熟蛋白序列内部存在重复序列与前人的报道一致。珊瑚藻亚基cDNA序列不同克隆子的测序结果表明,g亚基cDNA序列存在不同的3′末端,说明该基因可能存在多个拷贝或存在转录后加工。此外,扩增获得g亚基DNA序列(AY308999),比较表明编码区内部没有内含子存在。本文是对珊瑚藻R-藻红蛋白g亚基基因序列的首次报道。     

天麻中一种抗真菌蛋白基因的克隆

依据天麻(GastrodiaelataBl.f.flavidaS.Chow)抗真菌蛋白GAFP_1的N端部分氨基酸序列设计简并引物,通过RACE(快速分离cDNA末端)的方法扩增得到GAFP_1全长cDNA。该cDNA包含一个编码171个氨基酸的ORF,推导的多肽序列与测得的蛋白质部分序列相同;在5′端有一个长为55bp的5′非编码区;终止密码子下游有一个141bp长的3′非编码区,其中含有两个加poly(A)信号及长度为26个腺苷酸的poly(A)。经检索发现该推导蛋白序列与火烧兰(Epipactishelloborine)和二叶兰(Listeraovata)的甘露糖结合蛋白以及雪花莲(Galanthusnivalis)中的甘露糖结合凝集素具有很高同源性。     

普通烟草K^＋通道基因NKT4的克隆、序列和表达分析

通过比对拟南芥、胡萝卜、番茄和马铃薯的K+通道氨基酸序列得到了保守序列,设计1对简并引物,利用RT-PCR获得3条490bp的普通烟草K+通道基因中间片段.以其中一条中间片段设计特异性引物,应用RACE方法得到5′末端和3′末端cDNA序列.通过拼接并结合全长克隆及测序验证,获得一个未报道的普通烟草K+通道基因,并将其命名为NKT4(GenBank登录号为FJ233071).NKT4的cDNA全长为2937bp,其中5′非编码区45bp、编码区2679bp、3′非编码区213bp;编码区编码892个AA.构建了一个烟草、拟南芥及相关植物K+通道蛋白的系统进化树.基因表达分析表明,NKT4主要在烟草主根和侧根中表达,在烟草叶中也有少量表达.     

小麦花粉特异性表达的cDNA的分离及表达特性

应用抑制差示杂交和5′/3′RACE PCR方法分离了小麦(Triticum aestivum L.)花粉特异性表达的全长cDNA(TaPSG719,GenBank:AY451238)),该基因全长1 172 bp,5′非编码区序列长达329 bp,包含多个上游可译框架(uORF);该基因编码1 88个氨基酸的蛋白质,大小约20 kD,等电点为12.1.Northern杂交和RT-PCR分析表明该基因在成熟花粉特异表达,而在小孢子、叶片、根和未成熟的种子、幼茎和子房等组织几乎检测不到.进一步研究小麦花粉发育过程的表达水平表明,TaPSG719在单核和双核小孢子阶段不表达,在开花前5 d(已完成有丝分裂)开始表达并迅速增强达到高峰,但随着花粉的成熟表达水平逐渐下降.表明TaPSG719是一个花粉中晚期特异性表达基因.经BLAST同源性分析表明,与目前已登录的基因没有显著的同源性.Southern杂交表明TaPSG719可能为一个多拷贝基因.为研究TaPSG719 cDNA 5′非编码区序列的uORF对可译框架的翻译的影响,构建不同缺失或突变的表达载体,采用麦胚体外翻译系统,结果显示含uORF的5′非编码区序列能显著抑制蛋白质的翻译水平,表明TaPSG719基因表达至少部分是在翻译水平上调控.     

粘虫β-actin基因cDNA的克隆、序列分析及表达量检测

β-actin基因作为actin家族的一员,在基因定量实验中常用作内参基因。本实验运用RT-PCR和RACE技术,以粘虫Mythimna separata(Walker)cDNA为模板,对β-actin基因进行克隆获得全长cDNA序列,并利用生物信息学方法,对β-actin基因全长cDNA序列及推测得到的β-actin蛋白序列进行分析。结果表明,获得的粘虫核β-actin基因cDNA序列长度为1 472 bp,其中包括68 bp的5′非编码区、273 bp的3′非编码区和1 131 bp的开放阅读框,编码一个376个氨基酸蛋白,具有actin蛋白家族典型特征。推测得到的粘虫β-actin蛋白理论分子量为41.7497 ku,等电点为5.29,富含6种类型的特定功能位点。该蛋白序列与其他动物β-actin蛋白序列具有97.9%～99.7%高度同源性。β-actin表达量检测结果显示β-actin在6种不同组织间表达无显著差异(P>0.05),表明β-actin可作为研究粘虫不同基因表达水平高低的可靠内参基因。该基因的cDNA序列已经递交GenBank并获得登录号为GQ856238。     

珊瑚藻R-藻红蛋白rpeA和rpeB基因全长cDNA克隆与序列分析(英文)

依据珊瑚藻 (CorallinaofficinalisL .)藻红蛋白rpeA和rpeB的DNA序列 (AF5 1 0 986 )设计引物 ,通过PCR RACE方法扩增得到rpeA和rpeB的cDNA序列 .序列分析表明 ,该序列采用多顺反子转录策略 ,全长 2 2 5 7bp(AF5 42 5 5 4) ,排布顺序为 5′UTR rpeB 间隔区 rpeA 3′UTR .5′非编码区 4 93bp ,rpeB基因 5 34bp ,基因间隔区 1 0 1bp ,rpeA基因 4 95bp ,3′非编码区 6 34bp .在rpeA和rpeB的基因起始密码子上游均存在类似原核核糖体结合的Shine Dalgarno (SD)序列 .在rpeA基因终止密码子下游 1 1 0bp处还存在着一个可能的开放阅读框架 .经检索GenBank发现 ,真核红藻藻红蛋白中尚无有关cDNA序列的报道     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.