BIV在人源细胞MT-4中的活性研究

牛免疫缺陷病毒(Bovine immunodeficiency virus, BIV)在分类上属于反转录病毒科的慢病毒属,目前尚未见BIV感染人的报道.为进一步确定BIV对人源细胞的感染性,我们用BIV127cDNA转染人源细胞MT-4,通过RT-PCR检测到BIVgag基因的转录,IFA则显示BIV127的gag或gag-pol基因在MT-4细胞中得到了翻译,而RT值的测定也有力地说明BIV127cDNA已经在MT-4细胞内表达出有活性的反转录酶,但细胞传代实验表明BIV不能在MT-4细胞内复制.     

嵌合人/牛免疫缺陷病毒cDNA(pHBIV-2)传染性克隆的构建及其生物学活性

为探讨牛免疫缺陷病毒(BIV)Tat能否在功能上取代HIV Tat,构建用BIV tat取代HIV tat的嵌合人/牛免疫缺陷病毒(pHBIV-2)cDNA,将其转染人源MT4细胞.PCR、RT-PCR法检测到嵌合基因组在MT4细胞中可稳定地存在并转录;套式Alu-PCR法检测到嵌合基因组可整合到细胞基因组中;RTase活性测定及IFA检测显示,嵌合基因在MT4细胞中得到了翻译.结果表明,HIV的tat基因用BIVtat取代后产生的传染性cDNA克隆,仍能在人源MT4细胞中产生有复制性的重组病毒.     

人血小板因子4基因cDNA的克隆与序列测定

为研究人血小板因子4（hPF4)的生物学性能和用于肿瘤生物治疗的可能性,运用反转录聚合酶链反应（RT－PCR）从人工白血病细胞系HEL细胞总RNA中扩增出hPF4基因cDNA序列,将其克隆至pUC18载体中。序列分析证实克隆片段与献报道的hPF4基因cDNA序列完全一致,说明已成为克隆到hPF4基因cDNA。     

替换HIV-1衣壳蛋白基因SHIV的构建及其活性测定

将猴免疫缺陷病毒(Simianimmunodeficiencyvirus,SIVmm239)中gag基因的衣壳蛋白部分置换成人免疫缺陷病毒(Humanimmunodeficiencyvirustype1,HIV-1HXBc2)的相应部分,构建出替换了衣壳蛋白基因的人/猿嵌合免疫缺陷病毒(SHIV)原病毒DNA。用此SHIV原病毒DNA转染293T细胞,细胞中能够检测到嵌合病毒基因的转录与翻译;在细胞培养液上清中亦可检测到装配出的病毒颗粒。病毒颗粒形态正常,含有基因组RNA,具有反转录酶活性,嵌合的外源衣壳蛋白能够正确剪切,形成棒状的核心。将此嵌合SHIV病毒感染MT4细胞,病毒能够吸附并进入细胞,能完成反转录过程,但不能增殖。     

替换HIV-1衣壳蛋白基因SHIV的构建及其活性测定

将猴免疫缺陷病毒(Simian immunodeficiency virus,SIVmm239)中gag基因的衣壳蛋白部分置换成人免疫缺陷病毒(Human immunodeficiency virus type1,HIV-1 HXBc2)的相应部分,构建出替换了衣壳蛋白基因的人/猿嵌合免疫缺陷病毒(SHIV)原病毒DNA.用此SHIV原病毒DNA转染293T细胞,细胞中能够检测到嵌合病毒基因的转录与翻译;在细胞培养液上清中亦可检测到装配出的病毒颗粒.病毒颗粒形态正常,含有基因组RNA,具有反转录酶活性,嵌合的外源衣壳蛋白能够正确剪切,形成棒状的核心.将此嵌合SHIV病毒感染MT4细胞,病毒能够吸附并进入细胞,能完成反转录过程,但不能增殖.     

牛免疫缺陷病毒反式激活因子功能域的研究

牛免疫缺陷病毒(Bovine immunodeficiency virus, BIV)与人免疫缺陷病毒(Human immunod eficiency virus, HIV)同属反转录病毒科慢病毒属[1].BIV基因组5′端的长末端重复序列(LTR)起始病毒结构基因和非结构基因的转录[2],因而许多细胞因子和病毒编码的调节蛋白作用于LTR,以调节BIV的基因表达.     

人ING4的基因克隆及真核表达

目的克隆人生长抑制因子家族（inhibitor of growth famility member4,ING4）基因,构建其真核表达载体pEGFP—ING4。方法提取人胎盘总RNA,经RT—PCR扩增出ING4 cDNA,克隆至pEGFP—C2载体,构建的真核表达载体pEGFP—ING4用双酶切、基因测序进行序列鉴定;转染MCF-7细胞用荧光显微镜和免疫组化检测重组质粒的表达。结果RT—PCR产物为750bp的条带,双酶切和基因测序正确,转染可见目的蛋白融合表达。结论从人胎盘组织中成功克隆了ING4基因并构建其真核表达质粒在人MCF-7细胞中表达,为进一步研究1NG4基因的作用及抗肿瘤机制奠定了基础。     

人钠/碘同向转运体基因cDNA的克隆与序列测定

为研究人钠／碘同向转运体(hNIS)的生物学性能和用于肿瘤放射性碘治疗的可能性,运用反转录聚合酶链反应(RT—PCR)从人甲状腺组织总RNA中扩增出hNIS基因cDNA序列,将其克隆至pUCm-T载体中。序列分析证实克隆片段与献报道的hNIS基因cDNA序列完全一致,说明已成功克隆到hNIS基因cDNA。     

里氏木霉纤维二糖酶bg1Ⅱ基因的cDNA克隆及其在大肠杆菌中的表达

将里氏木霉总RNA反转录得到cDNA第一链，并以之为模板进行RT－PCR合成约1．4kb的纤维二糖酶基因cDNA,将所得的cDNA经测序后克隆到温度敏感型载体pJW2中，经PCR和双酶切鉴定筛出阳性重组子，温度诱导后，经酶活测定，bg1Ⅱ基因在大肠杆菌中得到了表达，酶活为0．75IU／mL。     

加工番茄多聚半乳糖醛酸酶（PG）基因的cDNA克隆的全序列测定

以加工番茄“87－5”为材料,采用反转录PCR（RT－PCR）技术将加工番茄G基因的cDNA序列克隆到pGEM-T载体上,并进行了全序列测定分析,结果表明,加工番茄的PG基因的cDNA与国内外报道的番茄PG基因的cDNA,在碱基序列及氨基酸序列上均有差异,说明番茄的PG基因具有多态性。     

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.