福尔马林固定铜鱼基因组DNA的提取与扩增

铜鱼（Coreius heterodon）作为长江中、上游的重要经济鱼类是研究三峡大坝阻隔效应的重要材料之一。然而,过去的铜鱼标本都保存在福尔马林溶液中,有必要探讨从福尔马林固定的铜鱼标本中有效提取基因组DNA的方法以及这些DNA用于微卫星和线粒体分析的可行性。本实验通过改进的酒精梯度浸泡法去除标本中的甲醛,然后用酚-氯仿抽提法成功地提取到了铜鱼标本的基因组DNA;设计引物后进行了线粒体和微卫星的PCR扩增,扩增产物经银染检测。微卫星扩增结果显示只有部分个体可以扩出目的带,而线粒体控制区部分区段在所有个体中均能稳定重复的扩出;mtDNA SSCP分析显示带型一致。结果表明,福尔马林固定的铜鱼标本可以被用来开展短片段的扩增和遗传变异分析等方面的相关研究。     

乙醇保存的动物标本基因组DNA提取方法的比较

为提高从乙醇长期保存的动物标本中提取大分子DNA的质量,用5种不同方法对动物组织进行预处理实验,然后采用SDS／蛋白酶K裂解,酚一氯仿抽提和乙醇沉淀提取总DNA,通过0．8％琼脂糖凝胶对模板进行电泳和PCR产物作鉴定,经比较,用0．9％NaCL法、PBS法和混合液法进行预处理,消除乙醇对Taq酶的影响以及蛋白质和核酸交联问题,为提取动物基因组DNA的3种更理想方法。     

福尔马林保存鱼类标本中大片段DNA的提取

从福尔马林保存的鱼类标本中获得高质量DNA是比较困难的。我们对前人的方法进行了如下改进：1）在标本的前处理过程中,通过长时间的缓冲液浸泡、短暂的加温、真空干燥来消除福尔马林对样品的影响;2）在样品消化过程中,加入相对过量的蛋白酶K和还原剂;3）提取DNA后立即进行PCR反应,并增加反应的循环次数和提高退火温度。通过这些改进,我们成功地从福尔马林保存的鱼类标本中提取出了高质量DNA;通过对比不同方法（福尔马林、酒精及冰冻）处理过的标本的DNA测序结果,表明该方法是值得信赖的;标本从死亡到用福尔马林处理之间的时间延搁可能是影响所提取的DNA质量的重要因素。     

不同保存方式下蝗虫组织DNA的提取及RAPD分析

为了开展蝗虫分子系统学研究,分别对冷冻、乙醇浸泡(100%、乙醇、70％乙醇)和干制蝗虫标本用饱和NaCl法进行了基因组DNA的提取,并用随机引物进行扩增,结果表明：70％乙醇固定的标本和部分干标本提取的总DNA得率较低,在琼脂糖凝胶电泳检测中大音琏分有明显降解,导致PCR扩增中信息缺失,甚至无扩增条带;而保存完好的干标本、-20℃冷冻标本和100%,乙醇浸泡标本提取的总DNA带型整齐,无拖尾,PCR扩增结果的稳定性好,成为蝗虫分子系统学研究中首选的三种保存方式。     

一种从人血凝块中提取基因组DNA的方法

介绍了一种新的从人血凝块中提取基因组DNA的方法,用该方法提取的DNA成功地应用于PCR和限制性酶切等后续实验中。基本过程为首先机械粉碎,然后高盐高EDTA溶液处理,含蛋白酶K和SDS的消化液变换温度消化,苯酚氯仿抽提。     

三种人全血基因组DNA提取方法的比较

目的：比较改良酚一氯仿抽提法、盐析法、试剂盒法从人全血中提取基因组DNA的效果,以期建立一种快速、经济的提取高质量基因组DNA的方法。方法：分别用上述三种方法从人全血中提取基因组DNA,通过紫外分光光度计、琼脂糖凝胶电泳、聚合酶链式反应（PCR）、限制性内切酶酶切检测提取的基因组DNA的产量、纯度和质量。结果：改良酚一氯仿抽提法与试剂盒法提取的基因组DNA相比,DNA的产量有统计学差异,DNA的纯度无统计学差异,但试剂盒法提取的基因组DNA有较明显的降解现象：盐析法与改良酚．氯仿抽提法、试剂盒法相比,基因组DNA的产量和纯度都存在统计学差异,并且基因组DNA聚合酶链式反应（PCR）扩增的稳定性也明显劣于另外两种方法;三种方法提取基因组DNA均能进行限制性内切核酸消化。结论：改良酚一氯仿抽据取法是一种经济、快速、高效、稳定提取人全血基因组DNA的方法,适用于批量临床标本处理。     

不同方式保存的蜘蛛基因组DNA提取方法的探索

基因组DNA的提取是在分子水平上进行研究的基础,提取的DNA的纯度、浓度及结构的完整性是进行基因工程各项研究的前提条件.本文用SDS法、CTAB法和饱和Nac1法等3种方法分别对75%乙醇浸泡、无水乙醇浸泡、-20℃冷冻及新鲜蜘蛛标本基因组DNA进行提取,并进行比较.实验结果表明:使用SDS法提取-20℃冷冻保藏的蜘蛛标本基因组DNA,可以达到分子生物学研究的要求.     

有效抽提乙醇中螨标本的核DNA

对如何有效地从乙醇保存的叶螨中抽提核基因组DNA作了探讨。70％乙醇保存的叶螨标本,经过干燥,TEN洗涤,蛋白酶K消化,酚—氯仿抽提,2倍体积无水乙醇沉淀等步骤,得到叶螨核基因组DNA沉淀,再用TE或无菌水溶解后,以其为模板,进行随机引物PCR扩增。结果显示.该方法抽提的DNA无Taq酶抑制物,且其纯度达到进行PCR反应对模板要求的程度。这为采用AP-PCR技术研究螨的系统分类提供了便利。     

福尔马林对固定标本DNA提取和扩增的影响

福尔马林被广泛应用于生物标本的长期保存。由于福尔马林可能影响标本DNA的质量,因此需要对福尔马林固定标本DNA的提取和扩增过程进行改进。影响从福尔马林保存标本中提取的DNA质量的主要因素包括福尔马林导致的DNA与蛋白质之间、蛋白质与蛋白质之间、DNA与DNA之间的交联,福尔马林溶液的化学成分、pH值及浓度,标本保存的时间和温度,标本保存部位等。本文总结了目前常用的对标本DNA提取和扩增过程的改进措施及其优点。     

人类肠道菌群DNA提取影响因素的研究

目的研究提取人类粪便中细菌基因组DNA的影响因素。方法采用溶菌酶和十二烷基磺酸钠(SDS)+石英砂+酚-氯仿抽提法提取粪便标本中细菌DNA,用PCR扩增细菌16SrDNA。比较不同粪便量,不同放置时间,不同放置温度下的粪便细菌DNA浓度及纯度改变;用Chao index评测高通量测序的结果。结果采用20mg粪便量提取出的细菌DNA的浓度最高;常温下放置3h后,提取的细菌DNA的浓度开始下降;在-20℃放置12h后,细菌DNA的浓度开始下降;-70℃放置48h后细菌DNA的浓度开始下降;样品纯度均在1.8以上;Chao index曲线趋于平缓表明测序数据量足够大。结论提取肠道细菌基因组DNA时,粪便标本取样量以20mg为宜,常温下粪便标本放置不超过2h,本研究所使用的方法所提取的DNA浓度可以达到高通量测序的样本要求。     

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.