中红侧茧蜂多分DNA病毒基本特征研究

本文首次报道中红侧沟茧蜂(Microplitis mediator)雌蜂卵巢中存在多分DNA病毒(Microplitis mediator Plolydnavirus,MmPDV),初步研究了MmPDV形态和基本生理生化特征。利用蔗糖密度梯度超速离心分离纯化了MmPDv粒子,电镜负染显示PDV粒子分三段,带有－明显的尾部结构,大小约为130×35nm;SDS-PAGE电泳条带较多,至少可以分辨出26个电泳条带,表明病毒粒子衣壳蛋白复杂;琼脂糖凝胶电泳显示MmPDV基因组至少由大小不同、丰度不等的14个DNA分子组成,用6种内切酶(EcoRI,HindⅢ,BssHⅡ,Pst I,BamH I,Bgl I)酶切MmPDV基因组后,估算出MmPDV基因组大小约为l08kb。用雌蜂输卵管萼液注射小地老虎幼虫,注射后的小地老虎体重和龄期发育动态表明,MmPDV具有抑制寄主生长发育的生理功能。     

黄地老虎颗粒体病毒cDNA文库的构建

以感染黄地老虎颗粒体病毒(Agrotis segetum ganulosis virus,AsGV)的黄地老虎幼虫为材料提取总RNA、分离mRNA,并反转录合成cDNA,构建了包括黄地老虎(Agrotis segetura,As)幼虫和黄地老虎颗粒体病毒的cDNA文库.用EcoR Ⅰ和HindⅢ限制性内切酶酶切AsGV基因组DNA,制备地高辛探针,与上述总RNA、mR-NA、cDNA杂交,从文库中筛选出AsGV的阳性克隆1081个,经cDNA测序,cDNA编码序列与基因组编码序列相符.并根据基因组阅读框序列合成引物,PCR扩增出59个阅读框的编码基因,也完全与基因组序列相符.     

黄地老虎核型多角体病毒的一些特性

黄地老虎核型多角体病毒(Agrotis segetum Nulear Polyhedrosis Virus简称AsNPV)的国内分离株(AsNPV^C),多角体呈六边形,大小1.7—2.6μm,为多粒包埋类型.每个病毒束内有2—7个核衣壳,大小约52nm×308nm.感染烟青虫(Heliothis assttlta)后分离到的多角体(As-HaNPV)其形状不规则,大小0.7—2.6μm,亦为多粒包埋类型.核衣壳2—6个不等,大小约40nm×300nm.EcoR1和HindⅢ限制性内切酶电泳图谱分析表明,AsNPV^CDNA和As-HaNPV DNA的EcoRI、HindIII酶切图谱一致,两者与HaNPV DNA的EcoRI,HindⅢ酶切图谱存在明显差异,AsNPV^C DNA的EcoRI酶切图谱共有15个片段,分子量在12.74×10⁶—1.18×10⁶道尔顿之间,总分子量约88.6×10⁶道尔顿,相当于134.25kbp.HaNPV DNA的EcoRI酶切图谱共有19个片段,分子量在13.89×10⁶—1.10×10⁶道尔顿之间,总分子量约93.86×10⁶道尔顿,相当于142.25kbp.AsNPV对黄地老虎2龄和4龄幼虫以及对烟青虫4龄幼虫的LD_{50分别为:1.4×10⁵pIB、7.4×10⁴PIB和2.61×10⁴PIB.}     

油桐尺蠖核型多角体病毒（羊楼洞株）基因组特性

用多种限制性内切酶单酶切、双酶切分析了油桐尺蠖核型多角体病毒（羊楼洞株）基因组DNA,同时用[α－32p）－dATP对几种酶的酶切产物进行末端标记。结果表明,此株病毒基因组约129kb,组成比较单一。与国内其它分离株基因组大小及酶切电泳图谱均有较大差别。     

黄地老虎颗粒体病毒cDNA文库的构建

以感染黄地老虎颗粒体病毒（Agrotis segetum ganulosis virus,AsGV)黄地老虎幼虫为材料提取总RNA,分离mRNA,并反转录合成cDNA ,构建了包括黄地老虎（Agrotis segetum,As)幼虫和黄地老虎颗粒体病毒的cDNA 文库。用Eco RI和HindⅢ限制性内切酶酶切AsGV基因组DNA,制备地高辛探针,与上述总RNA,mRNA,cDNA 杂交,从文库中筛选出AsGV的阳性克隆1081个,经cDNA测序,cDNA 编码序列与基因组编码序列相符。并根据基因组阅读框序列合成引物,PCR扩增出59个阅读框的编码基因,也完全与基因组序列相符。     

大尺蠖核多角体病毒DNA的限制性消化和物理图谱

用5种限制性核酸内切酶消化大尺蠖核多角体病毒(BsNPV)基因组DNA,所得片段数分别是:BamH Ⅰ,9;Bgl Ⅱ,7;Xho Ⅰ,10;HindⅢ 13;EcoR Ⅰ,12,从各个片段的累加测出BsNPV基因组的平均大小约为91,75kb;分子量约为59.60×10~6d。在单酶消化的基础上,用BamH Ⅰ/Bgl Ⅱ双酶消化得到16个片段(即9+7);大小为91,27kb,用、Bgl Ⅱ/Xho Ⅰ双酶消化产生7+10=17个片段,大小为90.04kb,由此组建了这三个酶在BsNPV基因组上的物理图谱。     

棉铃虫核多角体病毒基因库及其物理图谱

本文报道棉铃虫核多角体病毒DNA经限制性内切酶BamHI酶解,琼脂糖凝胶电泳分离,得到大小不同的11种片段。所得片段与BamHI酶解的pBR_(322)质粒DNA进行体外重组并转化大肠杆菌LE392菌株。根据菌落杂交和插入片段的分子量等鉴定,证明获得11个插入了病毒DNA片段的重组质粒,但其中两个大片段克隆的分子量比原片段小。通过限制酶EcoRI和BamHI酶解片段的交叉吸印杂交及用~(32)p标记的克隆片段与病毒DNA酶解片段杂交等方法,构建了病毒基因组BamHI的物理图谱。杂交结果表明,病毒基因组主要由独特的序列组成。     

蜀柏毒蛾核型多角体病毒结构多肽及基因组酶切分析

对蜀柏毒蛾核型多角体病毒(Parocneria orienta Nuclear polyhedrovirus,简称PaorNPV)形态结构、结构多肽、限制性内切酶图谱等特性进行了研究.采用不连续系统垂直板SDS-PAGE分析了PaorNPV的多角体蛋白、病毒粒子结构多肽.应用5种限制性内切酶对PaorNPV基因组DNA进行了酶切分析.结果表明:经热处理的多角体蛋白仅有一条带,分子量为31.5 kD,不经热处理的多角体蛋白有三条带,分子量分别为31.5 kD、29.1 kD、28.6 kD;病毒粒子包含有25种结构多肽,分子量范围在17.6-114.6 kD之间.PaorNPV DNA经BamH I.EcoR I、HindⅢ、Pst I和Xho I酶切分别产生9、12、12、12和14条片段.基因组大小平均为124.6 kb.     

高盐沉淀CTAB法提取温室菊花基因组DNA

根据温室菊花植物组织富含多酚、多糖的具体特性,对CTAB法加以改进:在待沉淀液中加入1/2体积5 mol·L～NaCI.改进后的方法获得的DNA质量良好,电泳条带清晰,提取过程无明显的DNA降解,基本上排除了多酚物质的干扰.以提取的DNA为模板,用一对引物扩增菊花中18S基因,得到条带单一,大小与已知一致,说明获得的DNA可以进行PCR扩增,EcoR I 酶切基因组DNA图谱表明,提取的DNA能被限制性内切酶完全酶切,可以满足相关的分子生物学研究.     

黄地老虎颗粒体病毒DNA的基因文库和物理图谱

利用EMBL 4——携带多切点连接序列的λ取代载体,建成了黄地老虎颗粒体病毒(AsGV)DNA基因文库,并绘制出AsGV DNA基因组的物理图谱。当体外包装效率达3 x 104pFU／μg DNA时,Sal和BamHI烈酶完全酶切的EMBL 4和BamHI部分酶切的AsGV DNA,按2：1的接头克分子比,用T4连接酶连接后,在BHB2688与2690体系中进行体外包装,再经在L95和ED 8654中的转染和转导,获得1．5×103噬菌斑。根据Clarke和Carbon公式,筛选概率达到复盖99％的AsGV基因组只需35个重组噬菌斑。我们随机挑取了35个重组噬菌斑,经快速琼脂糖凝胶电泳分析得到13个不同类型的重组噬菌斑,以32P标记的AsGV DNA为探针进行分子杂交,确定了BamHI在AsGV DNA基因组上位点的相邻位置。     

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.