Elymus sibiricus, E. nutans 和 E. burchan-buddae 的形态学鉴定及其染色体组亲缘关系的研究

为了进一步研究Elymus sibiricus L.、E．nutans Griseb．和E．burchan-buddae(Neuski)Tzelev [＝Roegneria nutans(Keng)Keng]的外部形态差异及其系统学关系,本文对这三种植物的6个穗部形 态性状进行了观测和比较,并对这三个Elymus种进行了种间杂交及杂种F1的减数分裂染色体配对行 为的分析研究。结果表明：这三个Elymus种的穗长及颖长等性状均变异很大,而内稃的长、宽则变异 不大并具有明显的种间差异。E. nutans×E．barchan-buddae及E.nutans×E．sibiricus的杂种F1均完 全不育,减数分裂不规则。E．nutans×E．burchan-buddae杂种F1的减数分裂构型为：7.70I+13.40 Ⅱ+0.06Ⅲ+O.08 Ⅳ,而E．sibiricus×E．nutans杂种F1的构型为11.98 Ⅰ+9.61Ⅱ+O.64Ⅲ+0.39 Ⅳ+0.01V。由本实验的形态学和细胞学的研究结果得出以下结论：1．利用内稃形态性状结合穗部 其它性状的差异能对这三个物种进行较准确的鉴定;2．E．nutans与E.burchan-buddae的亲缘关系较 近,而E．nutans与E．sibiricus的亲缘关系则较远;3. E,burchan-buddae×E．nutans的杂种Fl中存在着染色体配对控制因子。     

利用RAPD分析披碱草属、鹅观草属和猬草属模式种的亲缘关系

利用随机扩增多态性DNA（RAPD）技术对小麦族披碱草属、鹅观草属和猬草属3个属的模式种进行了基因组DNA多态性分析。42个引物产物的290条谱带中,257条（88.62%)表现出多态性,说明披碱草属、鹅观草属和猬草属3个属的模式种间具有丰富的遗传多样性。利用290个RAPD标记,计算材料间Nei氏遗传相似性系和遗传距离,在NTSYS程序中利用UPGMA进行聚类。结果表明,Elymus sibiricus种不同居群间的遗传差异较小,遗传距离在0.097-0.180之间。E.sibiricus,Roegneria caucasica和Hystrix patula的种间遗传差异明显,遗传距离在0.458-0.605之间。H.patula与E.sibiricus的亲缘关系较近。R.caucasica与E.sibiricus的亲缘关系较远。     

利用RAPD分子标记评价仲彬草属的种间关系

利用随机扩增多态性DNA(RAPD)技术分析了14种仲彬草属Kengyilia植物的种间关系。对34个OPRON公司十聚体随机引物进行多态性筛选,20个(58．8％)能产生多态性。14个引物产生的112个DNA片断,用于计算种间Jaccard遗传相似性系数分析,在NTSYS程序中利用UPGMA构建系统发育树状图。分析结果表明：(1)14个Kengyilia物种存在较大的遗传多样性;(2)青藏高原的物种与新疆的物种 的RAPD变异极大;(3)形态相似、地理分布一致的物种有一定的亲缘关系,聚类在一起;(4)RAPD结果与形态学和细胞学等分析结果一致。RAPD分析方法将为Kengyilia系统分类提供DNA水平上丰富的资料。     

同域分布垂穗披碱草和达乌力披碱草遗传多样性和遗传结构分析

披碱草属(Elymus L.)是禾本科(Poaceae)小麦族(Triticeae)中的一个多年生属,该属在青藏高原地区有广泛分布,多数物种是草原和草甸的组成成分,许多种类为品质优良的牧草.垂穗披碱草(E.nutans)和达乌力披碱草(E.dahuricus)同为禾本科小麦族披碱草属异源六倍体物种,染色体组组成皆为St...     

利用SSR标记对垂穗披碱草和老芒麦进行物种鉴定和遗传变异分析

垂穗披碱草(Elymus nutans)和老芒麦(Elymus sibiricus)皆为花序下垂类披碱草属物种,高海拔地区的E.sibiricus的部分变异类型也具有小穗紧密排列等特征,与E.nutans在形态学性状上具有较多的交叉,造成野外种质资源采集时进行直接的田间鉴定存在困难。本研究利用12对小麦族SSR引物对8份垂穗披碱草和10份老芒麦种质进行遗传变异和物种鉴定分析,UPGMA聚类分析表明供试材料明显可依据物种差异划分成两大类,主向量分析(PCo A)与聚类分析的结果保持一致。种质间遗传相似系数分析和分子方差分析(AMOVA)也表明种间变异远高于种内。另外,本研究筛选出3对引物,ESGS79和ESGS155能够在垂穗披碱草材料中扩增出特异性条带,Xgwm311能够在老芒麦材料中扩增出特异性条带,这3对引物能够作为区分垂穗披碱草和老芒麦的依据,为野外种质资源的收集以及田间育种工作提供指导。     

家蚕胚胎细胞系的DNA指纹图谱分析

在建立可靠的家蚕细胞系基因组DNA制备和PCR扩增技术体系的基础上,筛选具有稳定多态性位点的RAPD和ISSR引物,建立家蚕细胞系基因组DNA的ISSR和RAPD分子标记技术体系,检测家蚕细胞系的DNA分子标记多态性,构建细胞系的DNA指纹图谱。筛选出了26个ISSR引物和43个RAPD引物,通过PCR扩增在家蚕胚胎细胞系和传代昆虫细胞系等9个样品中分别获得了797条和1205条多态性条带,多态性达到89．9%和76．6%,不同细胞系的DNA多态性有较大差异,三个家蚕胚胎细胞系具有各自特有的DNA标记。测定了9个样品间的Nei's相似系数和遗传距离,构建了系统发育树,结果表明本实验室建立的3个家蚕胚胎细胞系和家蚕“夏芳×秋白”聚为一簇,亲缘关系较近,而来自不同物种的五个传代昆虫细胞系聚为一簇,它们之间的遗传距离比3个家蚕胚胎细胞系之间的遗传距离更小。     

小麦族四个属模式种的醇溶蛋白分析

利用酸性聚丙烯酰胺凝胶电泳 (APAGE)对小麦族披碱草属、鹅观草属、猬草属和仲彬草属 4个属的模式种进行了醇溶蛋白电泳分析 ,结果表明 :(1 ) 4个模式种具有明显的醇溶蛋白遗传多样性 ,其种间醇溶蛋白多态性高达 92 .3 % ;(2 ) Elymus sibiricus和 H ystrix patula具有相似的醇溶蛋白带型 ,而 Roegneria caucasica和Kengyilia gobicola的带型基本相似 ,其醇溶蛋白图谱能够反映一定的系统关系 ;(3 )不同收集地的 E. sibiricus材料间也存在明显的醇溶蛋白遗传差异 ,新疆的 E. sibiricus具有较丰富的醇溶蛋白带纹 ,而甘肃的 E. sibiricus的醇溶蛋白带纹较少。     

白地霉遗传多样性与生态地理起源地的相关性分析

采用随机扩增多态性DNA(RAPD)分子标记方法从22个随机引物中筛选出TubeB-03、TubeB-07、TubeB-12三个最佳引物分析来源于7个省区的23株白地霉的种内遗传多样性,并用UPGMA聚类分析法评价它们之间的亲缘关系.结果表明,不同来源地的白地霉通过RAPD分析显示出较高的遗传差异性,并且,在系统进化树上处于同一分枝的菌株来源于生态地理相近的区域,仅有个别例外.因此,应用RAPD分子标记技术对来自不同生态区的白地霉种内遗传多样性和亲缘关系进行分析是可行的.     

用RAPD分子标记探讨鹅观草属的种间关系

通过34个10碱基随机引物对鹅观草属(RoegneriaC.Koch)26个物种进行PCR扩增,28个引物能产生多态带。在NTSYS程序中,对16个引物扩增的186条扩增产物,计算Jaccard遗传相似系数,建立UPGMA聚类图。结果表明:(1)物种间遗传差异明显,具有丰富的遗传多样性;(2)StY和StYH基因组的物种存在着一定的遗传差异,并各有一定程度的分化,这种分化是与地理位置相联系的。相距越远,物种相似程度越低;(3)形态差异较小,基因组同源,地理分布一致的物种聚类在一起,表现出较密切的亲缘关系;(4)无芒类群的R.alashanicaKeng和R.magnicaespes(D.F.Cui)L.B.Cai与其余分析的24个Roegneria物种存在着极大的遗传差异;(5)分布于西亚的R.caucasicaC.Koch.与分布于东亚和中亚的物种存在着较大的RAPD变异,亲缘关系较远;(6)在对R.ciliaris(Trin)Nevski和R.japonensis(Honda)Keng、R.tenuispicaJ.L.YangetY.H.Zhou和R.pendulinaNevski、R.tsukushiensis(Honda)Ohwi和R.kamojiOhwi等的分类处理上,基本上与形态学和细胞学的研究结果一致。对RAPD标记在Roegneria系统分类研究中的应用进行了讨论。     

3种披碱草属(Elymus)牧草交配系统研究

通过测定3种披碱草属(Elymus)牧草,即老芒麦(E.sibiricus)、麦薲草(E.tangutorum)和披碱草(E.dahuricus)的花粉-胚珠比(P/O值)、杂交指数(OCI),结合不同授粉方式下这3种牧草的结实率,探讨这3种披碱草属牧草的交配系统,为披碱草属牧草杂交育种、丰产栽培等提供理论依据。结果表明,这3种牧草的花粉-胚珠比(P/O值)均介于31.9~396.0之间,交配系统属于兼性自交;杂交指数OCI值均为2,交配系统也属于兼性自交;结实率统计表明,以自交为主,异交可育。因此,这3种披碱草属牧草的交配系统属于兼性自交类型。     

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.