土壤可培养细菌DNA的提取及RAPD条件的优化

以改进的CTAB-溶菌酶-蛋白酶K裂解法抽提土壤可培养细菌总DNA,直接进行随机扩增多态DNA(RAPD)分析。分别测试了不同浓度镁离子、dNTP、模板DNA、引物、DNA聚合酶及牛血清白蛋白对反应结果的影响,通过各因子的组合研究,确定了土壤可培养细菌遗传多样性分析的稳定的RAPD反应体系。     

土壤可培养细菌DNA的提取及RAPD条件的优化*

以改进的CTAB 溶菌酶 蛋白酶K裂解法抽提土壤可培养细菌总DNA ,直接进行随机扩增多态DNA (RAPD)分析。分别测试了不同浓度镁离子、dNTP、模板DNA、引物、DNA聚合酶及牛血清白蛋白对反应结果的影响 ,通过各因子的组合研究 ,确定了土壤可培养细菌遗传多样性分析的稳定的RAPD反应体系。     

桔梗RAPD反应体系的优化

以通化桔梗为材料,用改进的CTAB法提取桔梗叶片的总DNA,通过对不同镁离子浓度、dNTP浓度、模板DNA含量、引物浓度、DNA聚合酶量条件下的RAPD扩增反应的效果,建立了一个适合桔梗的比较稳定的RAPD反应体系,用于桔梗遗传多样性分析。结果表明,桔梗RAPD扩增反应的最佳体系为:模板DNA20ng,dNTP150μmol/L,引物0.3μmol/L,Mg2+浓度2.0mmol/L,TaqDNA聚合酶1Unit,10×Buff-er2.0μL,PCR反应总体积为20μL。按此优化RAPD条件进行实验,重现性良好。     

卡瓦胡椒RAPD反应体系的建立

卡瓦胡椒RAPD分子标记的研究,目前国内外尚未见有报道。该试验通过CTAB法提取卡瓦胡椒基因组DNA,通过对模板DNA用量、Mg^2＋浓度、退火温度、电泳上样量等几个单因子试验来建立RAPD稳定扩增体系和反应条件,RAPD扩增结果重复性好,稳定可靠,为卡瓦胡椒RAPD分子标记的研究打下基础。     

孓遗植物桫椤RAPD分析中主要反应参数的影响

为得到桫椤RAPD扩增的最佳条件,对影响桫椤RAPD扩增的模板纯化方法、模板含量、酶浓度、Mg²⁺浓度、dNTP浓度和引物浓度及扩增程序等多种因素进行了探讨.结果表明,用玻璃奶和蛋白酶K纯化后获得的DNA作为模板进行RAPD反应,其扩增带比用未纯化的和仅用无水乙醇再沉淀的DNA为模板更亮,更清晰,重复性更好;模板浓度、酶浓度、Mg²⁺及dNIT浓度、引物浓度及退火温度这些因素都会对RAPD产生影响.经过本实验的探索,发现桫椤RAPD扩增的最佳体系是(2.5×10^-2mL反应体积):模板浓度为70ng,Mg²⁺浓度为2.5mmol·L^-1,dNTP为0.2mmol·L^-1,引物3×10^-4mL;最佳扩增程序为:94℃200s,一个循环;94℃60s,36℃60s,72℃120s,40个循环:72℃600s,一个循环:4℃保存.     

红曲菌基因组DNA提取及RAPD反应体系优化

为了建立一套适合红曲属真菌RAPD反应的优化体系,用改进的CTAB法提取红曲菌基因组DNA,采用单因素试验探讨RAPD反应体系中模板DNA、随机引物、Taq酶、Mg^2＋、dNTPs对扩增结果的影响。结果在20μL体积中,模板DNA20 ng、随机引物0、2μmol/L、Taq酶、Mg^2＋1.5mmol/L,dNTPs 1mmol/L的反应体系可得到稳定清晰的RAPD扩增图谱,为采用RAPD技术进行红曲菌种质资源遗传多样性研究奠定基础。     

皮下盘菌属及其近似类群RAPD-PCR反应条件的优化

以悬钩子皮下盘菌等总基因组DNA为皮下盘菌属(Hypodermade Not.)及其近似类群RAPD体系优化的模板,对模板DNA浓度、dNTPs浓度、Mg2+浓度、引物浓度、TaqDNA聚合酶浓度等反应体系以及退火温度和时间、延伸时间、循环次数等扩增程序条件进行优化,寻找出适合此类菌物RAPD-PCR反应的最佳反应体系和最佳扩增程序。     

荔枝DNA提取及RAPD扩增条件优化

为应用RAPD技术开展对荔枝种质资源的分析,以S43(GTCGCCGTCA)为引物,通过试验设计,分别研究了退火温度、模板浓度、引物浓度、dNTP浓度、Taq DNA聚合酶用量对荔枝RAPD-PCR反应的影响。建立并优化了适宜荔枝RAPD分析的扩增体系:20μL的反应体系,30ng的模板DNA度,0.25μmol/LRAPD引物、1.0UTaqDNA聚合酶,0.2μmol/LdNTP为荔枝适宜的RAPD-PCR扩增条件。     

宽叶缬草DNA的提取及正交优化RAPD反应体系

[目的]确定适合宽叶缬草RAPD分析的DNA提取方法以及建立最佳RAPD反应体系。[方法]比较宽叶缬草基因组DNA的两种提取方法(经典CTAB法、试剂盒法);采用正交设计L16(45),针对Taq DNA聚合酶浓度,d NTP浓度,Mg2+浓度,引物浓度,DNA模板浓度进行RAPD扩增,确立最佳RAPD反应体系。[结果]综合比较,试剂盒法较适合宽叶缬草基因组DNA提取;25μl最适宽叶缬草RAPD反应体系为:2.0 U Taq DNA聚合酶、0.4 mmol/L d NTP、4.0 mmol/L Mg2+、4.0μmol/L随机引物、60 ng模板DNA、2.5μl 10×buffer。[结论]试剂盒DNA提取法和正交优化的反应体系适用于宽叶缬草的RAPD分析,为进一步研究黔产宽叶缬草药材遗传多样性奠定了基础。     

香蕉RAPD分析初步研究

比较了不同提取方法对香蕉植株不同部位组织提取 DNA的质量及其 PCR扩增结果 ,对香蕉 RAPD分析中引物种类和浓度 ,复性温度 ,d NTPs,Taq DNA聚合酶浓度 ,热循环数等因素进行了比较影响分析。结果表明 ,虽然改良的 SDS法、CTAB法和 PVP法提取的植株嫩叶和吸芽 DNA提取量和纯度各不相同 ,但其 PCR扩增结果基本相同 ;相同克隆不同植株的 DNA其 PCR扩增结果也基本相同 ;建立了适合香蕉大规模 DNA多态性分析 RAPD反应体系 :2 5 μL反应液中 ,含 1倍缓冲液 ,0 .2 m Md NTPs,0 .3 2 p M随机引物 ,IUTaq酶 ,2 0 ng模板 DNA;反应循环数为 45 ,热循环条件为 94°C,1 min;3 7°C,1 min;72°C,1 .5 min;之前为 94°C,5 min;之后为72°C,1 0 min。在筛选的 2 49个随机引物中 ,有 1 8个在 7个品种上都能扩增出 3～ 1 0条比较清晰条带。     

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.