人类Connexin基因家族新成员-Cx44基因的克隆和特性分析

用绵羊和牛的Cx44基因(connexin 44 protein gene)序列对NCBI数据库进行Blast检索,得到一个相似性很高的人DNA序列(Human Genome Bank:AL138688),用GENSCAN程序分析AL138688,推测AL138688中包含一个编码区由1个外显子构成的基因——Cx44基因。人Cx44基因的开放阅读框为1320bp,推测编码435个氨基酸。用PROMOTORSCAN程序分析了其启动子。人Cx44基因与绵羊Cx44基因在1320bp有84.75％的一致性,其表达的蛋白有83％的一致性。用Map View将人的Cx44基因定位于13号染色体。     

亚麻中雄性不育基因同源序列MS2-F的克隆和表达分析

用同源序列克隆法从亚麻中克隆了雄性不育基因同源序列MS2-F cDNA(登陆号:EU363493).该cDNA全长1 91lbp,包含一个1 608 bp的ORF,编码535个氨基酸.推导的蛋白质序列中包含2个雄性不育保守区:NAD结合区域和雄性不育C-末端区域.该基因与油菜和拟南芥雄性不育基因的一致性分别为59.65%和59.16%,为花蕾特异表达基因,推测在亚麻花粉发育过程中与脂酰辅酶A还原酶有相似功能.MS2-F cDNA对应的gDNA大小为2 696 bp(登陆号:EU365361),含有8个内含子和9个外显子.     

猪CFL2b 基因cDNA克隆初步分析

利用基因表达谱芯片分析法筛选出与大白猪高肌肉产量-肌纤维形成有关的CFL2b基因.参考人和小鼠CFL2b基因序列,采用SMART-RACE技术结合EST序列拼接技术,从猪骨骼肌肌肉中首次克隆了猪CFL2b的全长cDNA序列（GenBank登录号EU561660,EU561661）,Northern杂交检测CFL2b基因 mRNA.结果表明,猪CFL2b基因含有2个转录本,长转录本3　012 bp,短转录本1　466 bp .CFL2b基因在多种真核生物中都有表达,且编码区序列非常保守,开放式读码框501 bp编码了166个氨基酸的蛋白质.氨基酸序列分析表明,猪CFL2基因与人和小鼠氨基酸同源性分别为100%和99.1%.核苷酸序列相似性分别为88.1%和74.9%.     

康宁木霉K801纤维素酶cbh2基因的克隆及序列分析

通过聚合酶链式反应（PCR）技术扩增得到纤维素高产菌株康宁木霉Trichoderma k■ningii K801纤维二糖水解酶（CBHII）基因全序列,并克隆到pGEM-Teasy Vector。序列分析表明,所克隆的cbh2基因长1611bp,包含了纤维二糖水解酶基因的完整编码区序列,并含有三个真核生物典型的内含子序列,其中四个外显子序列共同编码一个471aa的蛋白质。该序列是国内首次克隆得到的cbh2编码区全序列,与国外报道的T. reesei已知序列的同源性达到99.89％,只有两个碱基差别,而推测的氨基酸序列只有一个位置疏水性氨基酸之间发生替代,在推测的氨基酸序列上发现3个潜在的N-糖基化位点。     

康宁木霉K801纤维素酶cbh2基因的克隆及序列分析*

通过聚合酶链式反应（PCR）技术扩增得到纤维素高产菌株康宁木霉Trichoderma kningii K801纤维二糖水解酶（CBHII）基因全序列,并克隆到pGEM-Teasy Vector。序列分析表明,所克隆的cbh2基因长1611bp,包含了纤维二糖水解酶基因的完整编码区序列,并含有三个真核生物典型的内含子序列,其中四个外显子序列共同编码一个471aa的蛋白质。该序列是国内首次克隆得到的cbh2编码区全序列,与国外报道的T. reesei已知序列的同源性达到99.89％,只有两个碱基差别,而推测的氨基酸序列只有一个位置疏水性氨基酸之间发生替代,在推测的氨基酸序列上发现3个潜在的N-糖基化位点。     

苏云金芽孢杆菌chiA,chiB全基因的克隆、表达及其序列分析

以苏云金芽孢杆菌科默尔亚种15A3菌株基因组DNA为模版,用touchdown PCR方法扩增几丁质酶ChiA和ChiB的全基因序列(GenBank登录号:EF103273和DQ512474)。将PCR产物连接pUCm-T克隆载体,获得重组质粒pUCm-chiA和pUCm-chiB,分别转化E.coliXL-Blue。克隆的几丁质酶基因可以利用本身的启动子异源表达各自的蛋白,不需要几丁质作为诱导物。表达的几丁质酶能够分泌到胞外。证明15A3菌株可组成型表达2种几丁质酶。经核苷酸及氨基酸序列分析证明,chiA基因全长1426bp,含有343bp的上游非编码区和1083bp的ORF,编码360个氨基酸。推测成熟蛋白分子量为36kD,只有一个几丁质酶催化域。chiB基因全长2279bp,含有248bp的上游非编码区和2031bp的ORF,编码676个氨基酸。推测成熟蛋白分子量约为70.6kD,具有三个功能域。核苷酸序列分析显示chiA和chiB的启动子所处的位置及转录起始碱基都不相同,-35区相同,而-10区有两个碱基不同,SD序列也不完全一致。     

青花菜雄性不育相关基因BoDHAR的克隆与表达分析

以一个与甘蓝显性核不育相关的差异表达片段的序列为信息探针,通过在NCBI与TAIR网站数据库中进行同源EST序列搜索,经人工拼接、RT-PCR、PCR克隆与序列分析,获得了青花菜脱氢抗坏血酸还原酶DHARdehydroascorbatereductase基因的cDNA与DNA全长序列,命名为BoDHAR。并利用双链接头介导PCR的染色体步行技术(genomewalking)克隆了其上游644bp的5′端序列。所获的BoDHAR基因全长1486bp,存在两个内含子,DNA编码区序列633bp,编码210个氨基酸;序列分析表明BoDHAR与同源基因AT1G19570.1cDNA序列有82.3%的一致性,推导的氨基酸序列有79.6%的一致性;编码的水溶性蛋白存在多个磷酸化位点;5′端上游区存在明显的转录调控序列。半定量RT-PCR结果表明BoDHAR在可育系花蕾中的表达量明显高于不育系花蕾,在花药中的表达明显高于其它部位。     

铁皮石斛蔗糖磷酸合成酶基因的克隆与原核表达

应用同源序列克隆法克隆了铁皮石斛蔗糖磷酸合成酶(SPS)基因cDNA全长,并进行了原核表达分析,为进一步研究该基因的时空表达、功能分析及多糖合成机理提供理论依据。结果表明:(1)铁皮石斛SPS基因cDNA全长3 502bp,编码区3 186bp,GenBank登录号JF423929。该基因编码1 061个氨基酸,与文心兰的SPS基因氨基酸序列的一致性最高为93%,与其他科植物SPS基因的氨基酸序列的一致性均高于60%。(2)原核诱导表达结果显示,SPS基因在大肠杆菌中的重组蛋白分子质量约为118.7kD,其表达与序列分析推测的结论一致。(3)生物信息学分析表明,铁皮石斛SPS基因的二级结构包括了螺旋、β-折叠和无规则卷曲,是非跨膜结构的亲水性不稳定蛋白,有2个功能结构域,分别是蔗糖合成功能域及糖基转移功能域。     

雅致枝霉△6-脂肪酸脱氢酶基因的克隆及在酿酒酵母中的表达

根据真菌△^6 -脂肪酸脱氢酶基因保守的组氨酸Ⅱ区和Ⅲ区附近保守序列设计兼并引物进行RT-PCR,得到雅致枝霉（Thamnidium elegans）As3．2806△^6 -脂肪酸脱氢酶基因459bp部分cDNA序列,然后通过快速扩增cDNA末端技术（RACE）向两端延伸得到1504bp的△^6 -脂肪酸脱氢酶基因全长cDNA序列。序列分析表明有一个1377bp、编码459个氨基酸的开放阅读框TED6。推测的氨基酸序列与已知其他真菌的△^6 -脂肪酸脱氧酶基因的氨基酸序列比对,具有3个组氨酸保守区、2个疏水区及N末端细胞色素b5融合区。将此编码区序列亚克隆到酿酒酵母缺陷型菌株INVSel的表达载体pYES2.0中,构建表达载体pYTED6,并在酿酒酵母INVSel中异源表达。通过气相色谱（GC）和气相色谱,质谱（GC-MS）分析表明,该序列在酿酒酵母中获得表达,产生γ-亚麻酸（GLA）的含量占酵母总脂肪酸的7．5％。证明此序列编码的蛋白能将外加的亚油酸转化为γ-亚麻酸,是一个新的有功能的△^6 -脂肪酸脱氢酶基因（GenBank．AY941161）。     

早熟油菜成花相关基因LFY的克隆与分析

以甘蓝型油菜晚熟品种RG-8的早熟突变体RG-8M为材料,通过同源克隆法得到1个LEAFY(LFY)同源基因,命名为BnLFY。该基因cDNA全长为1 310bp,包含1个长为1 248bp的开放阅读框,编码415个氨基酸。序列分析表明,推测的氨基酸序列含双子叶植物LFY类蛋白特有的N端脯氨酸富集区、中央酸性区、亮氨酸拉链结构以及富含赖氨酸与精氨酸的碱性区;且与几种十字花科植物LFY类蛋白的氨基酸序列一致性均在84%以上。转录表达分析表明,BnLFY基因在油菜中为组成型表达。     

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.