中国东部栗疫病菌群体的遗传分化*

本实验采用RFLP技术,对中国东部栗疫病菌(Cryphonectria parasitica)进行了群体遗传结构的研究。313个参试菌株来自10个省(市)的16个群体(子群体),样本分布在北纬24°N—41°N。各菌株的DNA分别用限制性内切酶Pst Ⅰ和EcoR Ⅰ酶切,先后以10个低拷贝DNA探针和1个DNA指纹图谱探针进行了杂交和检测。结果表明,两个探针(pCB29和pMS29.1)的杂交图谱呈单态性;探针pCB19的杂交图谱显示,菌株DNA以PstⅠ酶切的为单态性,以EcoR Ⅰ酶切的则呈多态性;其他7个低拷贝探针的杂交图谱都呈多态性(Pst Ⅰ酶切)、指纹图谱探针的检测结果显示,辽宁凤城群体的菌株与中国东部其他群体的菌株相比,具有更多的限制性杂交片段,菌株间的遗传变异性也更大。     

中国东部栗疫病菌群体的遗传分化

本实验采用ＲＦＬＰ技术,对中国东部栗疫病菌进行了群体遗传结构的研究,３１３个参试菌株来自１０个省（市）的１６个群体（子群体）,样本人布在北纬２４°Ｎ－４１°Ｎ。各菌株的ＤＮＡ分别用限制性内切酶Ｐｓｔ Ⅰ和ＥｃｏＲⅠ酶切,先后以１０个低拷贝ＤＮＡ探针和１个ＤＮＡ指纹图谱探针进行了杂交和检测。结果表明,两个探针的杂交图谱呈单态性,其他７个低拷贝探针的杂交图谱都呈多态性、指纹图谱探针的检测结果显示,辽宁     

中国昆明(KM)小鼠线粒体DNA限制性内切酶图谱的研究

线粒体DNA的限制性内切酶图谱在不同的种系及亚种间存在多态性。我们分别用五种限制性内切酶BamHⅠ、EcoRⅡ、HidⅢ、PstⅠ、MspⅠ对60只中国KM小鼠(雌雄各半)的线粒体DNA进行了酶切电泳分析,结果未发现多态性,且这五种限制性内切酶图谱均与BALB/c小鼠相同。这表明中国KM小鼠与绝大多数实验小鼠一样,均起源于欧州的野鼠M.m.domesticu。未见到KM小鼠经其它亚种野鼠母系遗传污染的迹象。     

犬Ⅰ型腺病毒DNA的酶切分析及分子克隆

犬Ⅰ型腺病毒(CAV-1)弱毒用限制性内切酶EcoR Ⅰ,BamH Ⅰ,Pst Ⅰ,Sph Ⅰ和Hind Ⅲ消化分析后其图谱与强毒株相比没有差异。将弱毒DNA用Pst Ⅰ完全消化后以鸟枪法克隆到载体质粒pBluescrip'SK中,经用光生物素标记的CAV-1 DNA杂交筛选以及Pst Ⅰ分析重组质粒证明已将分子量为5.5,3.5,2.85,1.2,0.32和0.28Kb的CAV-1DNA片段克隆到质粒中。克隆到的这些片段将可考虑进一步研究作为探针检测犬及狐狸等野生动物的腺病毒感染。     

树qumtDNA限制性内切酶图谱及其与小家鼠褐家鼠的新缘关系

本实验用ApaⅠ,AvaⅠ,BamHⅠ,BclⅠ,BglⅠ,ClaⅠ,EcoRⅠ,EcoRⅤ,HpaⅠ,PstⅠ,PvuⅡ,ScaⅠ,XbaⅠ等13种限制性内切酶分析树qu(Chiromyscus chiropus) 的mtDNA限制性片段长度多态性,并用双酶解法构建了其中8种酶的限制性内切酶图谱。根据限制性片段差异法和分子钟,计算并讨论树qu和小家鼠(Mus musculus)、褐家鼠(Rattus norvegicus)的mtDNA遗传距离和亲缘关系。结果表明树qu与褐家鼠的关系较接近,两者的分歧时间在距今1500-2000万年前,即处于中新世早中期。     

大熊猫线粒体DNA的九种限制酶图谱

本文用9种限制性内切酶（BamHⅠ,BglⅠ,BglⅡ,EcoRⅠ,EcoRⅤ,PstⅠ,PvuⅡ,SalⅠ,XhoⅠ）分析大熊猫的线粒体DNA（mtDNA）。构建其中5种酶（BamHⅠ,EcoRⅠ,EcoRⅤ,PstⅠ,PvuⅡ）的mtDNA物理图谱。大熊猫mtDNA的分子大小约为16.4 Kb,酶切位点是随机分布。我们的结果为进一步研究大熊猫mtDNA进化提供了基础资料。     

滑鼠蛇肝线粒体DNA的限制酶图谱

用六种限制性内切酶BamHⅠ、EcoRⅠ、PstⅠ、BglⅠ、BglⅡ和SalⅠ对滑鼠蛇肝脏线粒体DNA(mtDNA)进行酶解。发现BglⅡ、PstⅠ、BamHⅠ、BglⅠ和EcoRⅠ在滑鼠蛇肝mtDNA上分别有1、2、3、3和4个切点。SalⅠ不能切割滑鼠蛇肝mtDNA。根据滑鼠蛇肝mtDNA的单酶、双酶完全酶解及部分酶解片段的数目和分子量,建立了滑鼠蛇肝mtDNA的限制酶图谱。     

油菜叶绿体基因组雄性不育特异DNA片段的定位

实验选用油菜湘矮不育系及同核保持系叶绿体DNA为材料,用4种限制性内切酶EcoRⅠ、BamHⅠ、PstⅠ和SmaⅠ完全酶解。在EcoRⅠ酶解的保持系ctDNA图式中,观察到唯一的差异片段E3.2kb。将此片段连接于载体pUC9进行克隆,经克隆杂交及电泳分析鉴定,获得重组子。以rRNA基因为探针,与EcoRⅠ酶解的保持系ctDNA杂交,其中一条阳性带显示在差异片段E3.2。进一步以E3.2片段为探针,与经过限制酶BamHⅠ、EcoRⅠ、salⅠ、BgⅢ、HindⅢ和PstⅠ酶解后的rRNA基因反杂交。根据rRNA基因图谱,这一与不育性有关的E3.2kb片段被定位于距16S rRNA基因5'端+2.0至+5.4kb的前导序列中。此结果表明,这段可能与花粉育性形成有关的片段定位于叶绿体基因组反向重复区。     

结核分枝杆菌中插入序列的研究

用人型复合分枝杆菌的特异插入序列IS6110和IS1081制 备探针,对5种限制性内切酶消化的结核分枝杆菌DNA进行杂交。结果表明,经PvuⅡ酶消化 的结核分枝杆菌DNA,用IS6110制备的探针进行杂交呈现高度多态性,说明IS6110对于人型 复合分枝杆菌分型研究和结核病流行病学研究具有很大价值。用IS6110制备的317bp探针对4 6株人结核分枝杆菌分离株多态性分析研究证实,这些菌株呈现高度DNA多态性,而且所含拷 贝数也极为不同,一般含7～18个拷贝。     

AFLP分子标记技术的改进

对AFLP技术的限制性内切酶组合进行了改进。以两个低频酶组合代替传统的高频酶与低频酶组合进行分子标记筛选,结果表明,采用低频酶组合(EcoRⅠ PstⅠ)产生的条带比传统酶切组合(EcoRⅠ MseⅠ和PstⅠ MseⅠ)要少且分布不均匀,多集中在150~800bp之间,条带信号强度要大,多态性明显得到提高,分子标记筛选成功率也得到了提高,而且其成本更低的特点有利于AFLP技术在我国的进一步推广普及。     

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.