貂肠炎病毒的核苷酸序列和基因组结构

本试验测定了已克隆的貂肠炎病毒(MEV)复制型(RF)DNA的核苷酸序列,确定MEV基因组全长约为5064个核苷酸(nucleotides,nt),推测了3'端和5'端结构,在5'端非编码区有3个51 nt的重复。MEV基因组序列与犬细小病毒(CPV)、猫细小病毒(FPV)有很高的同源性,结构基因区的同源性分别达99.1%和99.9%,但在5'端非编码区有较大差异。MEV基因组结构与CPV和FPV基本一致,有两个大的开放阅读框架,分别编码688和722个氨基酸。在map unit(m.u.)3.7和m.u.39处有两个启动子,在m.u.97处有poly A位点。NS2、VP1和VP2的mRNA都发生剪接。     

兔出血症病毒与细小病毒抗原相关性试验

用间接ELISA、ELISA交叉阻断法和交叉血凝抑制试验对兔出血症病毒(RHDV)与6种细小病毒进行抗原相关性试验。用间接ELISA证实,RFIDV与它们有轻度交叉关系,其抗原相关值分别为:小鼠细小病毒(MVM)5.59％;鹅细小病毒(GPV)3.54％;猪细小病毒(PPV)1.76％;水貂肠炎病毒0.7％。细小病毒间的抗原相关值:MEV与PPV为31.6％,MEV与MVM为35.36％;而CPV与MEM、PPV、MVM的相关值均为零,即无相关性。在ELISA交叉阻断法中证实:犬细小病毒(CPV)、猫泛白细胞减少症病毒(FPV)和MEV均不能阻断RHDV与其抗体结合,仅GPV有轻度阻断作用,其最大阻断率为40％。在血凝交叉抑制试验中,未发现RHDV与细小病毒及其相应抗体间存在交叉抑制现象。以上结果表明RHDV与细小病毒在血清学方面有轻度相关性。     

双拷贝v—cath基因的重组HaNPV的构建及毒力分析

利用HaNPV的Bac-to-Bac系统(Hanpvid)构建了双拷贝v-cath基因的重组HaNPV,即:除病毒自身的v-cath基因外,还带有由ie1启动子控制的早期表达v-cath基因的重组病毒dciHaNPV。Dot blot和Northern blot分析证明:重组病毒构建正确。用重组病毒感染Hz-AM1细胞,测定了dciHaNPV的TCID_(50)为3.16×10~7 TCID_(50)/mL。     

犬腺病毒、犬细小病毒联合PCR方法的建立与应用

根据GenBank报道的犬腺病毒(CAV)和犬细小病毒(CPV)序列,设计两对联合PCR引物,其中一对为CAV-1和CAV-2通用引物,另一对为CPV引物。在建立单项PCR基础上,通过优化Mg^2 离子浓度和循环参数等反应条件建立联合PCR,确定联合PCR条件为：96℃180s,96℃230s,56℃30s,72℃280s,30个循环。联合PCR结果显示：CAV—l扩增片段大小为497bp,CAV-2为l019hp,CPV为719hp;细胞和其它相关病毒对照均无扩增带。上述PCR产物经用限制性内切酶酶切和克隆测序,结果均与相应病毒的应有条带和序列相同。敏感性比较试验结果表明。联合PCR比用细胞培养分离病毒敏感。将联合PCR应用于15份CAV和CPV细胞培养物,5份CAV-1、1份CAV-2和3份CPV人工感染犬病料以及30份临床病料检测,并与电镜负染、HA／HI及病毒分离等方法的结果进行比较,结果显示,联合PCR的检出率和病毒分离结果一致,高于电镜负染和HA／HI试验。以上结果说明：CAV-1／12AV-2和CPV联合PCR不仅具有很好的特异性和敏感性,而且可以在短时间内(2．5h～3h)同时鉴定出上述三种病毒。因此具有良好的实验室诊断和临床应用价值。     

小鼠巨细胞病毒实验性持续感染模型的建立

应用小鼠巨细胞病毒(MCMV)Smith株,经腹腔感染我国繁殖的C57BL/6近交系小鼠,在高剂量感染组(10~(5.33)TCID_(50))、中剂量感染组(2×10~(4.33)TCID_(50))、低剂量感染组(2×10~(3.33)TCID_(50))均可引起感染。自感染后第5—14天,所有感染组鼠脾脏均可100％分离到病毒。自第14天开始,高、中剂量感染组唾液腺中已可100％分离到病毒;低剂量感染组唾液腺中到21天亦可全部分离到病毒;中剂量感染组小鼠追踪至第102天,唾液腺中仍100％可分离到病毒。MCMV感染后第21天的小鼠唾液腺切片中,还可见到腺体细胞核增大,核质疏松,有些细胞可见核内包涵体。本研究中全部对照小鼠均未分离到MCMV,说明本研究所用的C57BL/6小鼠可进行实验MCMV感染的研究。     

流行性出血热病毒对健康人外周淋巴细胞和大白鼠骨髓细胞染色体影响的研究

用流行性出血热病毒(EHFV)A9株,滴度为TCID_(50)10~(-5)/0.1ml,加入10名健康人外周血,作淋巴细胞姊妹染色单体互换(SCE)和染色体畸变的检测。每份血分对照组(不加病毒悬液)和A、B、C实验组(根据加不同病毒量而分)。其结果:一、SCE频率,实验组A(8.9±0.19)、实验组B(9.9±0.2)、实验组C(11.6±0.22)与对照组(6.57±0.15)比较,A、B、C、实验组均分别高于对照组,P<0.01,差异有高度显著性,A、B、C三个实验组比较,P<0.01,差异有高度显著性。二、染色体畸变,A、B、C三个实验组分别与对照组比较,P>0.05,差异均无显著性。用EHFV HA 108株,ID_(50)10~(-6)/0.02ml接种2—5日龄大白鼠脑内,15天后颈动脉放血处死,取骨髓细胞培养,另取幼大白鼠骨髓细胞培养作对照,检测SCE和染色体畸变。结果:一、SCE频率,实验组(9.8±0.35)高于对照组(5.4±0.19),P<0.01,差异有高度显著性。二、染色体畸变,实验组与对照组比较,P>0.05,差异无显著性。以上两个实验结果表明,EHFV作用于细胞,无论是在机体或试管内,都引起SCE频率增高,即EHFV促使DNA产生初级损伤,但不致染色体畸变。     

Raji细胞培养中HSV持续感染模型的建立及免疫因素(TNF IFNs)对它的影响

本文观察HSV持续感染Raji细胞培养物150天。发现整个感染过程似呵分为两个阶段:急性期(前30天)和稳定期(30天以后)。在急性期上清液中HSV滴度达10~(6.2)TCID_(50)/ml.病毒抗原阳性细胞达21％,死细胞达42％;在稳定期病毒和细胞处于相对平衡状态,上清液中IISV滴度在10~(3.5-4.2)TCID_(50)/ml,病毒抗原阳性细胞约占5—10％,感染细胞与对照细胞在生长特性上无明显差异。用rIFNs、rlL-2和TNF处理稳定期的细胞培养物,发现TNF和rlFNa能明显抑制HSV的复制,rIENy作用较弱,去除上述因子5天后又恢复到处理前水平。rlL-2无明显作用。用HSV抗体处理上述细胞培养物上清液中病毒和病毒抗原阳性细胞都消失,且在去除抗体后连续观察50天仍未出现。本实验为体外研究HSV持续感染提供了一个有用的模型。     

登革热Ⅳ型病毒在地鼠肾细胞培养内减毒的研究

本文报道登革热Ⅳ型病毒Ban18株通过原代地鼠肾细胞连续传代后的适应和减毒过程。 Ban18原株对原代地鼠肾细胞无病变或仅有极轻微病变,对乳小白鼠及断乳鼠的脑内毒力高达LD_(50)为Log6—7。通过连续传20—70代后,病变逐渐加重,出现时间缩短,二天即可达到细胞完全破坏。培养液内的病毒含量也随之提高达10~6—10~7/ml TCID_(50)。但随着传代代数增加,病毒对乳小白鼠的嗜神经毒力逐渐降低,脑内接种后仅个别发病或完全不致死。脑组织病理变化也较原株明显减轻,接种树鼩不产生病毒血症。以上结果符合弱毒株的减毒指标,是一株有希望的活疫苗毒株。     

烟青虫质型多角体病毒的形态及某些理化特性

本文对烟青虫(Heliothis assulta)质型多角体病毒(CPV)的形态大小以及某些理化特性进行了研究。烟青虫CPV多角体为正五角形的十二面体,大小为0.8-4.6μm;CPV 粒子为外形呈六角形或球形的廿面体,大小为62nm。CPV多角体蛋白的主要多肽为一种,分子量23000,为非糖蛋白。 用SDS-酚法提取的CPV基因,经Rnase I和Dnase I处理后在1%琼脂糖凝胶上电泳,结果表明 其基因是双链RNA,并由10个基因片段组成。各片段大小为0.3-2.68X10⁶,总分子量为15.85x10⁶。本文所报道的烟青虫质型多角体病毒在国内外尚属首次。     

犬细小病毒中国内蒙株VP2基因克隆及序列分析

从我国内蒙古地区流行的犬细小病毒病病犬的肠溶物中分离提纯犬细小病毒(CPV).提取病毒基因组DNA,并以此DNA为模板,采用人工合成的引物进行PCR 扩增,PCR产物经BamHI、SacI双酶切后,克隆于pUC19质粒的BamHI/Sac I位点.重组质粒pUCVP2经PCR鉴定、限制酶切分析和序列分析,结果表明:获得了犬细小病毒内蒙株(CPV-IM)VP2基因的全长克隆, VP2基因全长1755nt,与国外报道的美国1株(CPV-N)、美国2株(CPV-B)和猫全白细胞减少症病毒(FPLV)的核苷酸序列同源性分别为99.32%、98.29%、98.52%,氨基酸序列同源性分别为98.87%、97.09%、97.77%.     

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.