转基因克隆奶山羊大量生产重组人的抗凝血酶III蛋白质(rhATIII)

利用转基因克隆奶山羊乳腺生物反应器大量生产重组人的抗凝血酶III(rhATIII)蛋白质。其中包括: 筛选出人的抗凝血酶Ⅲ蛋白基因的cDNA序列; 利用山羊的b－酪蛋白基因的启动区, 终止信号和Enterokinase蛋白酶酶切DNA序列, 构建在乳腺中特异表达rhATⅢ的表达载体。同时在转基因载体的末端连接一个新酶素筛选基因(Neomycin)。再以细胞转染、G418筛选和体细胞核移植(动物克隆)等过程, 最后获得含有人的抗凝血酶Ⅲ基因的转基因克隆奶山羊。我们共获得了5个原代转基因公羊。第一只克隆羊在出生后78 d死亡, 解剖表明: 羊的肺部和肾脏等器官有异常。其它克隆公羊经过与崂山种母羊交配, 得到转基因后代, 其中两个原代转基因羊的后代母羊已成熟、所获得的奶经蛋白质电泳证明: 转基因克隆羊后代奶中含有约60 kD大小的rhATⅢ糖蛋白; 经Elisa检测表明: 在奶中含有大量活性的rhATⅢ, 在来源于两个不同克隆公羊的后代母羊奶中的rhATⅢ含量分别为0.4 mg/L和3 g/L。此研究证明: 转基因奶山羊可以大量地生产具有很高活性的rhATⅢ。用这种方法生产的rhATⅢ通过蛋白质提纯, 制成注射针剂, 将可用于人的抗凝血酶III缺乏症的治疗、预防血栓和重大手术过程中的止血的作用等。     

转基因克隆奶山羊大量生产重组人的抗凝血酶Ⅲ蛋白质(rhATⅢ)

利用转基因克隆奶山羊乳腺生物反应器大量生产重组人的抗凝血酶Ⅲ(rhATⅢ)蛋白质.其中包括:筛选出人的抗凝血酶Ⅲ蛋白基因的cDNA序列;利用山羊的β-酪蛋白基因的启动区,终止信号和Enterokinase蛋白酶酶切DNA序列,构建在乳腺中特异表达rhATⅢ的表达栽体.同时在转基因载体的末端连接一个新酶素筛选基因(Neomycin).再以细胞转染、G418筛选和体细胞核移植(动物克隆)等过程,最后获得含有人的抗凝血酶Ⅲ基因的转基因克隆奶山羊.我们共获得了5个原代转基因公羊.第一只克隆羊在出生后78 d死亡,解剖表明:羊的肺部和肾脏等器官有异常.其它克隆公羊经过与崂山种母羊交配,得到转基因后代,其中两个原代转基因羊的后代母羊已成熟、所获得的奶经蛋白质电泳证明:转基因克隆羊后代奶中含有约60 kD大小的rhATⅢ糖蛋白;经Elisa检测表明:在奶中含有大量活性的rhATⅢ,在来源于两个不同克隆公羊的后代母羊奶中的rhATⅢ含量分别为0.4mg/L和3 g/L.此研究证明:转基因奶山羊可以大量地生产具有很高活性的rhATⅢ.用这种方法生产的rhATⅢ通过蛋白质提纯,制成注射针剂,将可用于人的抗凝血酶Ⅲ缺乏症的治疗、预防血栓和重大手术过程中的止血的作用等.     

人抗凝血酶Ⅲ转基因羊的外源基因漂移风险分析

目的:研究转基因羊发生基因漂移的可能性.方法:利用实时荧光定量PCR技术检测人抗凝血酶Ⅲ转基因羊及与其密切接触的野生型山羊、转乙肝表面抗原基因羊、转β-干扰素转基因羊、狗、鸡和鹅的血样中人抗凝血酶Ⅲ基因的含量.结果:人抗凝血酶Ⅲ转基因只在人抗凝血酶Ⅲ转基因羊血液中检测呈阳性.结论:人抗凝血酶Ⅲ基因没有在转基因羊和非转基因羊及其它动物间发生漂移,提示转基因羊对于环境是安全的.     

乳腺特异高表达人促红细胞生成素转基因奶山羊的制备

目的制备乳腺特异性高表达人促红细胞生成素（hEPO）转基因奶山羊。方法采用牛β-乳球蛋白基因（BLG）调控元件和hEPO全长编码序列基因组DNA构建真核表达载体,应用受精卵原核注射的方法制备hEPO转基因山羊。结果在原核注射获得的188头羔羊中,经Southern blot法检测有4头羊含有hEPO基因,其中3头为母羊,1头公羊于出生后20d死亡;3头转基因母羊hEPO基因的拷贝数分别为1、10、2;Western blot检测结果显示转基因羊乳中的hEPO分子质量为32kDa;MTT法检测结果表明,在泌乳10d的3只转基因羊乳汁中,每毫升乳汁中hEPO活性分别达到1.17×10^2IU、1.90×10^4IU、1.91×10^4IU。结论牛BLG能够调控hEPO基因在山羊乳腺中高表达,为实现其他药用蛋白在山羊乳腺中表达奠定了基础。     

乳腺生物反应器表达的重组人抗凝血酶Ⅲ的分离纯化

抗凝血酶Ⅲ(AT Ⅲ)是人体内最重要的抗凝血物质,利用转基因技术生产重组人抗凝血酶Ⅲ(rhAT Ⅲ)受到了越来越多的关注,如何有效地将rhAT Ⅲ从转基因羊奶中分离纯化出来是实现其产业化的关键所在。本研究建立了基于等电点沉淀和肝素亲和层析的纯化工艺,实现了rhAT Ⅲ的高效、快速纯化。先用等电点沉淀法,快速去除了占总蛋白50%左右的酪蛋白;然后用肝素亲和层析纯化rhAT Ⅲ,并系统考察了pH值和温度对rhAT Ⅲ稳定性的影响,以及pH值和操作条件(洗脱梯度、流速和上样量)对rhAT Ⅲ分离效果的影响。在优化的条件下,rhAT Ⅲ纯度达到99%以上,蛋白收率达到90%,活性收率约为50%。所建立的纯化工艺简单、快速,rhAT Ⅲ收率高,为今后工艺放大提供了重要的依据和参考。     

由成年转基因山羊体细胞而来的克隆山羊

在已经获得的乳腺特异性表达人促红细胞生成素 (rhEPO)成年转基因山羊 (Caprahircus)的基础上 ,取其耳尖成纤维细胞和卵巢颗粒细胞 ,进行体外传代培养 ,然后将这种培养的转基因山羊的体细胞移入去核的处于第Ⅱ次减数分裂中期的卵母细胞中 ,并进行电融合 ,构建重构胚胎 ,重构胚胎在体内培养 6d ,再将发育至囊胚或桑椹胚的重构胚胎移入同步情期的寄母羊子宫内。结果 ,有 2只寄母羊妊娠并最终产下 2只成活的克隆山羊。她们分别来自同一成年母羊的耳尖成纤维细胞和卵巢颗粒细胞。克隆羊经PCR RFLP图谱分析显示 :以克隆羊组织DNA为模板的PCR产物与相应的提供体细胞的基因羊的PCR产物的酶切图谱完全一致 ;并且经PCR对外源hEPO基因检测表明 2只克隆山羊均携带hEPO外源基因。由此证明获得了转基因成年体细胞的克隆山羊     

以经过转染的乳腺上皮细胞生产克隆羊

为研究转基因乳腺上皮细胞发育的全能性,利用电转染方法将人乳铁蛋白(hLF)乳腺特异性表达载体电转染山羊乳腺上皮细胞,经G418和PCR筛选获得阳性克隆细胞株,经催乳素诱导的细胞株上清液用Western blotting方法检测hLF的表达。以转基因与上清液中表达hLF均为阳性的细胞为核供体细胞,进行山羊体细胞核移植。结果为:16株细胞表达重组hLF,分子质量为75 kD;将144枚重构胚移入16只同步发情的山羊输卵管中,在移植后的30 d、60 d和90 d的妊娠率分别为87.5%、81.3%和62.5%;最终3只受体妊娠足月,产下3只克隆羊,克隆效率为2.1%,PCR-RFLP分析表明克隆羊均来自供体羊细胞,但没有整合外源基因。结果表明,hLF转基因乳腺上皮细胞能分泌hLF;乳腺上皮细胞经转染、筛选和长期培养的条件下,能保持发育的全能性。     

重组人SOD1/3转基因山羊的制备及表达产物的检测

设计了以hSOD1、hSOD3为编码序列,以山羊β-酪蛋白/CMV杂合启动增强子构建乳腺特异性表达载体rhSOD1、rhSOD3,共转染母山羊胎儿成纤维细胞,采用PCR和扩增产物序列分析筛选获得SOD1/3克隆细胞株,应用体细胞核移植(SCNT)制备双转基因山羊。出生小羊经PCR和扩增产物序列分析验证是否成功整合外源基因,经Western blotting、ELISA及体外活性检来验证分析表达产物。结果表明:获得SOD1/3转基因山羊胎儿成纤维细胞系6株;原代双转基因体克隆山羊1只(♀);从该转基因羊乳汁中检测到rhSOD1、rhSOD3,浓度分别为:88.81±8.36 mg/L和267.82±12.67 mg/L;转基因羊乳汁中重组人SOD酶活性为1 432±157 U/mL。研究表明,以双载体和单标记基因转染山羊胎儿成纤维细胞可获得双基因整合转基因细胞系,并且以SOD1与SOD3功能基因均可在山羊乳腺中共同表达,表达产物具有较好的生物学活性。     

整合人lactoferrin基因的山羊体细胞支持核移植克隆胚的体外发育

克隆了人lactoferrin基因和山羊[[beta]]-casein基因5′端调控区, 构建了人lactoferrin的乳腺表达载体, 并将该载体利用脂质体介导转染了奶山羊胎儿成纤维细胞, 获得了稳定整合人lactoferrin基因的转基因体细胞克隆17个, 其中PCR和Southern Blot检测阳性的细胞克隆14个, 阳性率82.4%。以转基因体细胞为供体细胞进行了核移植, 获得了能够体外发育的山羊转基因克隆胚胎, 体内成熟卵母细胞来源的核移植囊胚率为64.8%, 体外成熟卵母细胞来源的核移植囊胚率为51.7%, 证明了山羊转基因体细胞能够支持克隆胚的进一步发育。     

转基因羊的培育

英国ＰＰＬＴｈｅｒａｐｅｕｔｉｃｓ公司和英国Ｒｏｓｌｉｎ研究所小组向羊的胎儿成纤维细胞中导入人凝血因子Ⅸ基因,培育出转基因羊。该小组在今年２月成功地培育出克隆羊“Ｄｏｌｙ”。这次不是克隆羊,而是在羊的胎儿成纤维细胞中导入人基因,获得产羔。用小鼠确立了...     

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.