一株受二噁英类化学物质诱导表达的萤光素酶肝癌细胞系

 构建了一对二英类化学物质敏感的人肝癌细胞株 ,用于二英类化学物质生物筛选和快速半定量检测 .首先构建一在二英增强子调控下的萤光素酶报告基因质粒 ,该质粒转染入人肝癌细胞株HepG2 ,筛选稳定转染细胞株 .2 ,3,7,8 四氯代二苯并二英 (TCDD)诱导稳定转染细胞株萤光素酶表达 ,发光检测萤光素酶活性 .该细胞株用于TCDD检测 ,检测下限为 1 1pmol L ,线性范围为 1～ 10 0pmol L .该细胞系的建立可用于二英类化学物质的生物筛选和快速半定量检测     

二恶英反应增强子调控的虫荧光素酶报告基因质粒的构建

为加强二恶英类化学物质的快速筛选和半定量检测,我们构建了一在二恶英反应增强子调控下的虫荧光素酶报告基因质粒。二恶英反应增强子来源于pHAV质粒,MMTV启动子来源于pCatM质粒,上述两者连接后与虫荧光素酶载体连接,转染人HepG2肝癌细胞,以2,3,7,8四氯代二苯并二恶英(TCDD)诱导报告基因表达后检测虫荧光素酶活性。结果表明该质粒中虫荧光素酶的表达受二恶英反应增强子的调控,且在一定浓度范围内虫荧光素酶的活性与TCDD的量呈线性关系。研究显示该质粒转染的细胞株有望用于快速筛选及半定量检测二恶英,可进一步加强研究作为二恶英类化学物质监测的常规方法。     

Sp1真核表达载体的构建及对USP22基因转录活性的影响

目的 克隆人sp1基因,构建真核表细胞达载体pVAX-Sp1,研究其对USP22基因转录活性的影响.方法 Trizol试剂快速提取人肝癌细胞株HepG2总RNA,经RT-PCR扩增Sp1基因序列,与pVAX1真核表达载体连接;测序、酶切鉴定重组载体;pVAX1-Sp1与含USP22启动子的萤光素酶报告质粒共转染HepG2细胞,双萤光素酶报告系统检测萤光素酶活性表达.结果 测序及酶切结果显示重组质粒pVAX1-Sp1构建成功;高表达sp1可使USP22启动子的转录活性降低（P＜0.01）.结论 成功构建了sp1真核表达质粒,sp1对USP22启动子具有转录抑制作用.     

用于筛选shRNA的新型双萤光素酶报告基因载体的构建及应用

目的:构建一个新型双萤光素酶报告基因载体用于准确高效地筛选有效抑制靶基因表达的shRNA。方法:采用PCR、定向克隆、基因重组等分子生物学方法,将双萤光素酶报告基因系统中需要的报告基因载体、shRNA真核表达载体和内参载体三个功能,整合于一个新型的双萤光素酶报告基因载体pFLuc-C-TK-RLuc-shRNA之中。应用该载体对靶向人PD1基因以及Furin基因的shRNA进行干涉效果比较。结果:应用p FLuc-C-TK-RLuc-shRNA载体进行单质粒转染方法与传统的三质粒转染方法均提示shRNA#1对靶基因PD1的抑制效果最优;但是使用新型双萤光素酶报告基因载体检测结果的标准差数值显著低于传统方法。以pFLuc-C-TK-RLuc-shRNA单质粒转染方法得到的各组样品结果的均一性显著提高,能够准确地反映出shRNA#3较shRNA#2具有更强的Furin基因抑制作用;而传统方法未能有效判断二者的差异。结论:新型双萤光素酶报告基因载体简化了操作步骤,降低了传统三质粒共转染方法所引起的检测结果大幅波动,进一步增强了双萤光素酶报告基因系统的信噪比,提高了筛选抑制靶基因表达shRNA的准确性。     

人免疫缺陷病毒假病毒药物筛选模型的构建及其应用

目的:构建人免疫缺陷病毒(HIV)假病毒模型,用多种HIV逆转录酶和蛋白酶抑制剂作用于该模型,以检测其是否能有效用于HIV抑制药物的筛选。方法:通过载体改造获得最终慢病毒载体puc18-NL4-3-LUC-stop,其中含有萤光素酶基因,将该载体与包膜质粒VSV-G共转染293FT细胞,包装产生HIV假病毒,在假病毒包装和病毒感染293FT细胞的过程中加入蛋白酶和逆转录酶抑制剂,通过检测感染细胞中萤光素酶的表达来检测该模型的有效性,并利用此模型检测药物的抗病毒效果。结果:将HIV逆转录酶和蛋白酶抑制剂作用于该假病毒模型时发现萤光素酶的表达得到很大程度的抑制。结论:建立了HIV假病毒药物筛选模型,该模型以萤光素酶基因作为报告基因,快速灵敏,在抗HIV药物筛选中有一定的应用价值。     

携带荧光素酶基因肝癌细胞株的构建及在肝癌原位移植瘤模型中应用

[目的]构建稳定表达荧光素酶基因的人肝癌细胞株,建立可实时观察的肝癌原位移植瘤模型。[方法]构建含有萤光素酶基因的慢病毒载体,利用慢病毒三质粒系统磷酸钙共转染HEK 293T细胞,收集纯化病毒感染肝癌细胞SMMC7721,嘌呤霉素(puromycin)结合有限稀释法筛选稳定转导细胞株,将细胞原位注射裸鼠肝组织,建立原位肝癌动物模型。[结果]包装纯化的慢病毒悬液的滴度为8.4×106TU/m L,感染肝癌细胞后成功筛选到稳定表达的肝癌细胞株。利用该细胞株成功建立原位注射肝癌裸鼠模型,经活体荧光成像系统观察到肝癌细胞在活体动物体内的分布情况。[结论]荧光素酶肝癌细胞株的成功构建及利用该细胞株建立的原位移植瘤肝癌动物模型为肝癌的治疗研究奠定了基础。     

表达萤光素酶的HIV药物筛选细胞模型的建立

目的:构建基于萤光素酶的单次复制人免疫缺陷病毒(HIV)细胞模型,用于抗HIV药物的筛选。方法:构建含萤光素酶报告基因的假型慢病毒质粒,将疱疹性口炎病毒外膜糖蛋白(VSV-G)的表达质粒、HIV-1 Rev蛋白表达质粒、HIV Gag-Pol蛋白表达质粒和含萤光素酶报告基因的重组慢病毒质粒共转染HEK 293FT细胞,制备假型慢病毒;在假型慢病毒生产和再感染新鲜HEK 293FT细胞的过程中加入逆转录酶和蛋白酶抑制剂(如AZT),检测再感染的细胞中萤光素酶的表达水平,从而判断药物对HIV的抑制作用。结果:构建了含萤光素酶报告基因的重组慢病毒质粒pLenti-Luc;利用已知抗HIV药物AZT进行测试,发现HIV药物处理组细胞中萤光素酶活性远低于对照组。结论:建立了基于萤光素酶的HIV药物筛选细胞模型,该系统使用单次复制的报告病毒,具有良好的安全性,而使用萤光素酶基因作为报告基因使该系统具备极高的敏感性,该系统适合于进行高通量药物筛选。     

动物活体成像生物发光稳定细胞株的构建

目的:构建组成型表达萤光素酶基因的载体,建立稳定高表达萤光素酶的MCF-7乳腺癌细胞株,检测其对细胞增殖的影响及在传代后的表达效果.方法:以载体pGIA.20为模板,PCR扩增萤火虫萤光素酶基因,将其克隆到载体pIRESpuro2上,将获得的pIRESpuro2-Luc经酶切和测序验证后,转染293T、MCF-7及ZR...     

利用萤光素酶标记的肿瘤细胞建立肝癌原位移植模型及其活体成像

目的：利用生物发光成像技术非侵入性地监测活体裸鼠原位肝癌发展过程。方法：将包含有萤火虫萤光素酶基因的pCI-neo-Luc载体转染人肝癌HepG2细胞系,筛选获得具有高萤光素酶活性的细胞克隆;利用流式细胞仪对萤光素酶表达的稳定性进行初步研究,并分析细胞的生物发光情况;持续表达萤光素酶的肿瘤细胞培养扩增后被植入裸鼠皮下,2周后以形成的异体瘤作为供体瘤,进行肝脏原位移植手术;对建立的肝癌原位移植模型,用影像学资料显示肿瘤部位,用IVIS成像系统动态监测肿瘤生长情况。结果：体外影像的结果显示,表达萤光素酶细胞的数量与发光强度呈正相关;活体成像的结果显示。成功地建立了萤光素酶标记的原位肝癌动物模型。结论：生物发光成像可以监测活体内肝癌演进过程,为抗肿瘤药物的筛选和评价提供了新的手段和工具。     

RNA干扰技术对肝癌细胞内源survivin基因表达的影响

应用RNA干扰技术（RNAi）研究针对凋亡抑制因子survivin的siRNA抑制肝癌细胞株内源survivin基因的表达.转染重组质粒pshRNA-survivin至肝癌细胞株SMMC-7721,通过免疫荧光、蛋白质印迹和半定量RT-PCR检测survivin蛋白表达及mRNA转录水平的变化.结果表明：构建的三种重组质粒pshRNA-survivin1/2/3均能明显抑制survivin基因的表达;应用免疫荧光检测survivin基因的表达,转染重组质粒pshRNA-survivin的实验组survivin荧光强度明显低于转染载体pTZU6＋1和pshRNA-GFP对照组;蛋白质印迹结果表明,重组质粒pshRNA-survivin明显抑制survivin蛋白的表达,抑制率为62%～78％,通过半定量RT-PCR检测到survivin基因mRNA转录明显减少,抑制率为57%～64％.由上述结果可以得出结论：重组质粒pshRNA-survivin可明显抑制SMMC-7721细胞内源survivin的表达和mRNA的转录,为survivin介导的肿瘤基因沉寂疗法提供实验基础.     

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.