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1.
12株酵母菌的亲缘关系分析   总被引:1,自引:0,他引:1  
克隆了9株假线酵母和1株克鲁维酵母的25SrDNA片段,测定其5′端部分苷酸序列与报道的Candidaalbicans及Saccharomycescerevisiae25SrDNA相应区域的核苷酸序列比较,采用neighbor-joining和boot-strap法分析并绘制系统树,结果提示CandidakefyrCBS834与Kluyveromyces cicerisporusCBS4857亲缘  相似文献   

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t-PA cDNA的克隆及其在毕赤酵母中的表达   总被引:5,自引:0,他引:5  
应用PCR方法,在t-PA cDNA5'端引入合适的限制酶位点和酵母分泌信号肽,与酵母表达载体pPIC9重组,构建表达质粒pSTE-Y,利用LiCl转化法转化酵母菌YS108,在MM和MD平板上筛选表型,PCR筛选t-PA cDNA与酵母染色体整合而形成的阳性克隆,阳性克隆经甲醇诱导表达后,用SDS-PAGE证明表达产物的分子量为6kDa左右,用酪蛋白板溶圈法测定t-PA的活性。Mut^s表型菌表  相似文献   

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酵母K.cicerisporus基因组中有启动子功能的DNA片段的克隆   总被引:1,自引:0,他引:1  
利用以3′-氨基糖苷磷酸转移酶基因(APHI)为报告基因的一套启动子探针质粒pSK-kan401、pSK-kan1105、pSK-kan1238,从酵母Kluyveromycescicerisporus基因组中克隆到8个有较强启动功能的DNA片段,分析出3′端DNA序列,并在酵母Kluyveromyceslactis中通过检测报告基因与3-磷酸甘油醛脱氢酶基因(GAPDH)的mRNA表达量的比值,确定它们的功能强度,其中pSK-kan401-41和pSK-kan1105-51两个克隆的插入片段具有较强的启动子功能,并证明这两个片段在酵母K.cicerisporus中也有启动子功能。  相似文献   

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测定了果蝇nasuta亚群7个分类元和外群D.immigrans的核糖体基因转录间隔区(ITS,interanscribed spacer),包括5.8SrDNA和2SrDNA长约1.1kb的DNA片段序列。结果表明:D.pallidifrons、Taxon I、Taxon J享有共同的序列;D.albomicans则与D.s.neonasuta共享1个序列。序列之间存在少量的插入缺失和碱基替代。  相似文献   

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以r射线诱发转化的大鼠胚胎细胞(REC:cyc:r33)的DNA构建粘粒基因库,用总基因库DNA转染NIH/3T3细胞,产生转化灶的DNA作二轮转染,二轮转化的NIH3/T3细胞内有大鼠REC:myc:r33DNA中具转化活性的N-ras基因,用不对称PCR和DNA序列分析法证明,REC:myc:r33细胞中鼠N-ras的活化是由于第61位密码子的A→G点空为。NIH/3T3转化灶中鼠N-ras也  相似文献   

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通过逆转录(RT)-聚合酶链式反应(PCR),从中国人丙型肝炎病毒(HCV)携带者的血清中扩增并克隆到2段cDNA片段,即HCV基因组C区抗原基因C831cDNA片断(约530bp)和NS3区抗原基因C33ccDNA片段(约860bp)。C33ccDNA片段同C831cDNA片段经连接   肽Ser-Pro-Gly-Ser连接成为基因嵌合体C33c-C831(约1400bp)。C33c-C831基因嵌合体同温控型原核表达载体pBV220重组,构建成表达质粒pBV/C33c-C831,并在大肠杆菌细胞中获得了重组嵌合抗原C33c-CL的表达。通过酶切分析和Western免疫印迹法,对约占菌体可溶性蛋白9%的表达产物做了鉴定。采用TritonX-100和盐析处理,获得粗提表达产物。粗提的表达产物经尿素裂解和离子交换层析纯化,得到可用于检测抗HCV核壳蛋白和抗NS3区抗体的重组嵌合抗原C33c-CL。对C33c-CL做抗原性分析发现,它同时具有完整的C33c抗原和C22抗原的免疫反应活性,完全能替代单纯的C33c和C22抗原。该嵌合抗原在血清学诊断中有重要的应用价值,可望成为新一代HCVEIA诊断试剂的优选抗原。  相似文献   

7.
日本血吸虫26kD抗原基因在BCG中的表达   总被引:5,自引:0,他引:5  
研究了外源基因日本血吸虫26kD抗原(Sj26GST)在卡介苗(bacilusCalmete-Guerin,BCG)、耻垢分枝杆菌(M.smegmatis)和大肠杆菌(E.coli)中的表达.运用重组DNA和聚合酶链反应(PCR)等分子生物学技术,以表达Sj26GST的E.colipGEX衍生质粒为模板,经PCR得到编码Sj26GST的全长cDNA片段.将其按正确的阅读框顺序,克隆到人结核杆菌热休克蛋白(heatshockprotein,HSP)70的启动子下游,再将HSP70启动子和Sj26GST基因一起亚克隆到E.coli-分枝杆菌穿梭质粒pBCG-2000中,得到E.coli-分枝杆菌穿梭表达质粒pBCG-Sj26.pBCG-Sj26电转化入BCG和M.smegmatismc2155中表达Sj26GST抗原,所表达的天然重组Sj26GST(rSj26GST)为可溶性蛋白,在SDS-PAGE上分子量为26kD处可见明显的表达蛋白带.其表达量分别占BCG和M.smegmatis菌体总蛋白的15%和10%.可见,Sj26GST基因能在BCG中高效表达.  相似文献   

8.
中国苋属nrDNA的ITS序列分析及其系统学意义   总被引:11,自引:0,他引:11  
运用PCR直接测序法,对苋属(Amaranrhus L.)15个种及外类群鸡冠花(Celosia cristata L.)nrDNA的ITS区(包括ITS-1,5.85rDNA和ITS-2)进行序列测定。结果表明苋属植物的ITS序列总长度为629-632bp,长度变异仅发生在ITS-1区(250-253bp)。采用PAUP软件进行系统发育分析表明:分布于中国的苋属植物可分为3组,即刺苋组(secg  相似文献   

9.
由PCR反应扩增了28种冷杉属(AbiesMill.)植物的nrDNA的ITS(包括ITS1、ITS2和5.8rDNA)片段,经过与100bp和1kb的标准分子量DNA进行比较和某些类群ITS的全序列和部分序列测定,发现分布于墨西哥和2种分布于北美的冷杉属植物的ITS片段长度约为2500bp,而分布于欧亚大陆和其他分布于北美的冷杉植物的ITS长度约为1700bp,二者相差约800bp。A.brac  相似文献   

10.
文摘     
文摘基因工程980098血清中小型基因组DNA片段的直接PCR[英]/Sandfold,A.J.…∥BioTechniques.-1997,23(5).-890~892[译自DBA,1998,17(1),98-00019]开发了一种简易、快速的方法,...  相似文献   

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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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
肝癌中HBV和HCV基因和抗原的分布及意义   总被引:1,自引:0,他引:1  
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  相似文献   

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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.  相似文献   

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