禽白血病病毒J亚群内蒙株的分离与鉴定

本研究从曾见典型禽骨髓性白血病(Myeloid Leukosis, ML)病例的内蒙古某肉种鸡场随机选取的淘汰肉种鸡中,分离出一株J亚群禽白血病病毒(Avian leukosis virus Subgroup J, ALV-J).利用PCR和间接免疫荧光反应进行鉴定,J亚群禽白血病病毒内蒙株可以被两对ALV-J特异性引物扩增(特异条带约2.2kb和545bp);且在特异性单抗的间接免疫荧光检测中呈现强阳性荧光反应.此外,对山东一例肉种鸡骨髓性白血病病例亦进行了J亚群禽白血病病毒的分离与鉴定.2.2kb PCR扩增物的测序结果表明,两株分离病毒的同源性为96.9%,与已分离的SD9901和YZ9901株ALV-J同源性达94.2%～95.4%.     

禽白血病病毒J亚群内蒙株的分离与鉴定

本研究从曾见典型禽骨髓性白血病(Myeloid Leukosis,ML)病例的内蒙古某肉种鸡场随机选取的淘汰肉种鸡中,分离出一株J亚群禽白血病病毒(Avian leukosis virus Subgroup J.ALV-J)。利用PCR和间接免疫荧光反应进行鉴定,J亚群禽白血病病毒内蒙株可以被两对ALV—J特异性引物扩增(特异条带约2．2kb和545bp);且在特异性单抗的间接免疫荧光检测中呈现强阳性荧光反应。此外,对山东一例肉种鸡骨髓性白血病病例亦进行了J亚群禽白血病病毒的分离与鉴定。2．2kb PCR扩增物的测序结果表明,两株分离病毒的同源性为96．9％,与已分离的SD9901和YZ9901株ALV-J同源性达94．2％～95.4％。     

禽白血病病毒J亚群跨种传播研究

禽白血病病毒J亚群(ALV-J)为致瘤性禽反转录病毒,主要引起髓细胞瘤。ALV-J囊膜基因的高频突变率使其具有了跨种传播的潜力。为探索ALV-J在宿主选择压力下是否可实现跨种传播,本研究以ALV-J顺次感染易感宿主禽(SPF鸡,火鸡),然后过渡到抗性宿主禽(山鸡,鹌鹑和鸭),检测排毒规律、观察病理变化、分析分离株囊膜基因(env)遗传突变。结果显示,通过对ALV-J体内选择压的逐级建立,实现了对抗性宿主山鸡和鹌鹑的感染,但鸭未感染,而用原代毒直接攻毒抗性禽则未出现感染。SPF鸡和火鸡感染率均为100%(16/16),而山鸡和鹌鹑的感染率分别为37.5%(6/16)和10%(3/30)。感染宿主均呈免疫耐受状态,并可见肝脏、脾脏、肾脏及心血管系统炎症反应和组织损伤。通过有义突变与沉默突变比值(NS/S)分析,山鸡毒株和鹌鹑毒株超变区hr2的NS/S值均为2.5,由此可知山鸡和鹌鹑ALV-J分离株的突变是由宿主选择压造成的,且提示hr2区突变是ALV-J实现跨种传播的关键区域。序列同源性分析发现火鸡、山鸡和鹌鹑ALV-J分离株与原始毒逐渐远离,而与ALV-J原型株HPRS-103株却呈接近趋势,但HPRS-103不感染山鸡和鹌鹑,其机制还有待于进一步研究。     

蛋鸡J亚群禽白血病的分子生物学诊断

根据J亚群白血病病毒(ALV-J)原型株HPRS-103的序列设计了一对针对外源性ALV-J引物H5和H7,从发生ML病死鸡的肿瘤、骨髓、肝脏、脾脏和输卵管组织中提取DNA作为模板,经PCR扩增得到长度为545bp的片段,对其序列进行测定后,与ALV-J原型株HPRS-103的序列进行了比较,发现其核苷酸同源性为97．4％,所编码氨基酸的同源性为96．1％。该片段含有ALV-J gp85编码基因的部分序列和ALV-J pol基因的部分序列,从分子水平上证实了蛋鸡发生J亚群禽白血病,进一步证明了此前根据病理学观察、免疫组化及免疫荧光诊断的结果。这是首次从分子水平上证明蛋用型鸡发生J亚群禽白血病。     

致蛋鸡血管瘤J亚群禽白血病病毒cDNA全序列分析

【目的】了解近年来我国商品蛋鸡群中以血管瘤为主要表型的J亚群禽白血病病毒(Avian Leukosis Virus subgroup J,ALV-J)的分子生物学特性,为控制ALV-J在鸡群中流行提供基础资料。【方法】采用PCR扩增和序列分析技术,对分离自血管瘤或者血管瘤与髓样细胞瘤(Myeloid Leukosis,ML)并存的3株蛋鸡ALV-J毒株前病毒DNA的全序列及3株商品蛋鸡血管瘤型分离毒和1株商品蛋鸡ML型分离毒的致瘤关键性序列进行研究。【结果】来自血管瘤或者血管瘤与ML并存的商品蛋鸡分离毒株与来自肉鸡分离毒株的全序列差异明显,在遗传进化树上分属两个大的分支;研究发现商品蛋鸡血管瘤及ML混合病例分离毒JS09GY3与JS09GY6株的引物结合位点(Primer Binding Site,PBS)-Leader中出现极为罕见的连续19bp的插入突变,其与劳斯相关病毒1(Rous Associated Virustype1,RAV-1)、劳斯相关病毒2(Rous Associated Virustype2,RAV-2)及劳斯肉瘤病毒施密特-鲁宾二氏[Rous sarcoma virus(strain Schmidt-RuppinB),RSV-SRB]毒株序列相同;通过对U3区调控元件的分析,发现血管瘤商品蛋鸡病例分离毒NHH与JS09GY5的U3区各发生1处连续序列缺失,出现了极为独特的c-Est-1、TCF11及C/EBP结合位点,这些调控元件可能与病毒的致肿瘤特性相关;所测的5株血管瘤商品蛋鸡分离毒均保留完整E元件,而所有肉鸡分离毒的E元件均发生了几乎相同的大部分序列缺失;首次发现血管瘤商品蛋鸡分离毒JS09GY3的E元件中有11bp的连续插入序列。【结论】商品蛋鸡血管瘤型ALV-J与肉鸡分离毒在全序列上差异明显,U3、DR1和E元件等区域有一部分特殊的突变与毒株的宿主类型和肿瘤表型有一定关系,其功能尚需进一步研究。而血管瘤型、髓细胞瘤型ALV-J可能是ALV-J与其它反转录病毒的重组毒。     

禽白血病病毒J亚群（ALV—J）的血清学调查及PCR诊断

禽骨髓细胞性白血病 (ｍｙｅｌｏｉｄｌｅｕｃｏｓｉｓ) (或称禽骨髓细胞瘤 ,ｍｙｅｌｃｙｔｏｍａｔｏｍａｔｏｓｉｓ) (ＭＬ)是由禽白血病病毒 (Ａｖｉａｎｌｅｕｋｏｓｉｓｖｉｒｕｓ)Ｊ亚群 (ＡＬＶ Ｊ)引起的禽的一种肿瘤性传染病[1] ,ＡＬＶ -Ｊ是英国的Ｐａｙｎｅ于 199     

禽白血病病毒的亚群和准种多样性及其在不同选择压作用下的演变

禽白血病病毒(avian leucosis virus,ALV)是最易发生突变的病毒之一,它有多个亚群,其中感染性和致病性最强的J亚群(ALV-J)的囊膜蛋白gp85基因和LTR片段的变异性更强。ALV-J不同毒株间gp85差异很大,即使同一株病毒或同一分离物内的准种也有很大的多样性。在1988年ALV-J出现后最初的10年里,基本上只在白羽肉鸡中流行。最近10多年在我国的流行中,它又逐步适应蛋用型鸡、黄羽肉鸡及多种我国固有的地方品种鸡,而且诱发肿瘤细胞的类型也逐渐多样化,显然这与病毒的演变有关。现汇集了过去25年里国内外147个代表毒株的gp85序列及部分毒株的LTR序列,利用现代病毒分子流行病学技术,比较分析了ALV-J的准种多样性及其在不同选择压作用下的演变。以此为预测ALV进一步演变及制定更有效的预防控制措施提供新的科学数据。     

我国1999-2003年间ALV-J野毒株gp85基因变异趋势

通过接种鸡胚成纤维细胞(CEF)、间接免疫荧光试验(IFA)和聚合酶链式反应(PCR),连续五年从全国各地的送检病料中分离到14株J亚群白血病病毒(ALV-J).为了动态观察ALV-J囊膜表面结构蛋白(GP85)的变异情况,对这14株野毒株的囊膜糖蛋白基因(env)进行了克隆和测序,将它们与HPRS-103株的GP85的氨基酸序列进行了比较,结果表明ALV-J的囊膜表面结构蛋白发生了很大的变异,而且这些变异主要集中在高变区hr1、hr2和vr3;这些野毒株GP85的氨基酸序列的同源性在86.6%～100%之间(从同一鸡场中分离到的两株ALV-J即BJ00302与BJ0303的同源性为100%,其它毒株之间的同源性均小于100%);有义突变与沉默突变的比例显示这3个高变区极有可能是免疫选择压作用的位点.     

鸡内源性类J亚群禽白血病病毒gp85基因的克隆及分析

为深入探讨J亚群禽白血病病毒(Avian leukosis virus subgroup J,ALV-J)的亚群特性,利用ALV-J gp85基因两侧的序列片段为引物,从正常SPF蛋鸡、商品肉鸡和DF1细胞基因组中完整地扩增了内源性类ALV-J gp85基因。肉鸡和DF1细胞内源性类ALV-J gp85基因同源性达99．9％;SPF蛋鸡内源性类ALV-J gp85基因与肉鸡和DF1细胞的内源性类ALV-J gp85基因之间同源性达95．6％、95．3％。三种不同来源的内源性类ALV-J gp85基因DNA与IMC10200株ALV-J的gp85基因的同源性分别为91．8％、94．1％、94．0％;与ALV-J原型株HPRS-103gp85基因的同源性分别为95．6％、98．3％、99．9％。内源性类ALV-J gp85序列与外源性ALV-J gp85基因具有相似或一致的ORF和Jameson-Worrlf抗原表位优势。     

禽白血病A亚群病毒gp85的单因子血清制备及其特异性鉴定

【目的】为了研究出一种能够针对A亚群禽白血病的快速特异性诊断试剂。【方法】将A亚群禽白血病病毒(ALV-A)SDAU09E1株接种于DF1细胞上,以感染细胞DNA为模板,通过PCR方法扩增出1023bp的ALV-A-gp85基因。将其正确阅读框架插入表达载体PET-32a(+)中,实现在BL21(Rosetta)宿主菌中表达。将纯化的融合蛋白常规免疫小鼠,制备得抗血清。【结果】实验成功获得52.8kDa的重组融合蛋白,且具有良好的免疫原性。间接免疫荧光试验(IFA)表明该血清可与ALV-A和ALV-B反应,但不与ALV-J反应。【结论】该实验首次在国内外研制出能用于鉴别性检测经典的A/B亚群ALV的单因子血清,可与ALV-J特异性单抗互补作用于外源性ALV感染的鉴别性诊断。我国鸡群同时受经典的ALV-A/B和新出现的ALV-J困扰,鉴别诊断非常必要,研究这种试剂具有较高的实用价值。     

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.