蓟马基因组DNA提取方法的改进

在昆虫分子生物学的研究中,从昆虫样品中有效地获得总DNA是分子实验成功的前提。但是,常规提取方法由于不能保留昆虫所有的形态特征,这对于体形较小的珍稀标本是不适用的。文中通过对改进的盐析法和STE法与KAc法的对比,发现盐析法和STE法提取的DNA质量明显优于KAc法,并且能够通过针刺从单头蓟马中成功提取DNA而不影响形态鉴定。2种提取方法的优点是单头蓟马在提取过DNA以后,虫体仍然可用以做成永久玻片进行形态鉴定。提取的DNA经实验证明,可以顺利的进行mtDNA-COI和rDNA-ITS2基因序列引物的扩增。     

烟粉虱全基因组DNA四种提取方法的比较

获得大量、高质量的全基因组DNA是在DNA水平上研究许多生物的分子机制的基本前提。微小昆虫由于其体型微小,单头提取DNA浓度低,无法满足部分试验所需。为寻找一种方便、快捷、高效的全基因组提取方法,参考国内外单头微小昆虫基因组DNA提取常用方法,以烟粉虱为研究材料,选取醋酸钾(KAc)法、盐析法、氯仿-异戊醇法和苯酚提取法四种方法进行多头烟粉虱的全基因组DNA提取。通过微量核酸蛋白分析仪、基因组DNA直接琼脂糖凝胶电泳、甲基化敏感扩增多态性(Methylation sensitive amplification polymorphism,MSAP)引物扩增产物的琼脂糖凝胶电泳对DNA样品进行检测,比较提取DNA的产量、质量,并综合分析各提取方法所需时间及所用试剂的毒性大小。结果表明,盐析法提取的DNA平均浓度为521 ng/μL,纯度能满足分子检测要求,用MSAP引物能得到较好的扩增结果,相比其它方法,盐析法更简便、快速且无毒。因此盐析法是多头烟粉虱全基因组DNA提取的最佳方法。     

一种提取麦红吸浆虫基因组DNA的方法

介绍一种可从单头麦红吸浆虫Sitodiplosis mosellana(Gehin)成虫、幼虫和蛹成功地提取基因组DNA的方法。经检测提取DNA样品浓度为100～200ng/μL,纯度在1.4～1.6范围之间,以此为模板,可顺利地进行RAPD引物扩增。该提取方法简单、安全、经济,可为小型昆虫基因组DNA的提取提供参考。     

蚜虫基因组DNA提取方法的改进

蚜虫基因组DNA的提取是蚜虫分子生物学研究中的难点。参照动物基因组DNA的提取方法,根据蚜虫体型微小,体表有外骨骼的特点,对SDS法作了改进。改进的方法无需用组织捣碎棒破碎虫体,操作简便。与现在常用的提取方法相比,改进的SDS法能快速、有效地提取单头蚜虫的基因组DNA,适用于RAPD随机引物和测序引物的PCR扩增。     

一种经济高效提取实蝇基因组DNA的方法

单头实蝇高质量基因组DNA的获得为实蝇分子生态学研究奠定了重要基础。本文提出一种经济高效的实蝇基因组DNA提取方法,该方法广泛适用于不同虫态、不同保存条件的实蝇标本,与传统的CTAB法和SDS法相比操作简单、耗时短,得率高。     

利用末龄幼虫蜕和蛹壳对单头昆虫基因的无损伤检测

【目的】在昆虫基因功能等相关研究中,通常需要利用单对交配策略来筛选纯合突变品系,如何在配对前确定个体基因型同时又不对昆虫造成损伤,显得尤为重要。本文旨在探讨利用末龄幼虫蜕和蛹壳进行单头昆虫的无损伤基因检测方法。【方法】针对大小不同的3种鳞翅目昆虫斜纹夜蛾Spodoptera litura Fabricius、二点委夜蛾Athetis lepigone M?schler和小菜蛾Plutella xyllostella Linnaeus,收集末龄幼虫蜕及蛹壳,利用常规分子生物学技术进行基因组DNA提取、靶标基因PCR扩增、琼脂糖凝胶电泳检测、连接转化和单克隆测序验证。【结果】从斜纹夜蛾、二点委夜蛾末龄幼虫蜕和蛹壳提取的基因组DNA,以其为模板对GOBP1基因进行PCR扩增,产物经琼脂糖凝胶电泳检测得到单一、明显的条带,进一步经连接转化和单克隆测序得到目的序列;但由于小菜蛾末龄幼虫蜕和蛹壳太小,以同样方法提取的基因组DNA浓度太低,PCR产物经电泳检测,未能得到目的条带。【结论】对于与斜纹夜蛾和二点委夜蛾相近或更大的昆虫,可以利用单头末龄幼虫蜕或蛹壳提取基因组DNA,通过常规PCR技术克隆特定基因序列,为突变品系筛选过程中昆虫个体的无损伤基因型检测提供了方法。     

牛肉干中牛基因组DNA提取方法的比较研究

为得到一种快速、稳定、准确、优质的牛肉干DNA的提取方法,本研究比较了SDS法、改良CTAB法、酚-氯仿抽提法以及4种试剂盒提取法的提取效果。通过比较DNA的提取质量、提取效率,并对提取的DNA进行PCR扩增分析。DNA提取结果表明,7种提取方法均能从牛肉干中提取出DNA,其中采用SDS法、酚-氯仿法、试剂盒1法和试剂盒4法所提取的DNA质量较高,A260/A280比值在1.7~1.9之间。试剂盒3法提取所花的时间最少,DNA得率最高,但DNA的纯度最低。PCR扩增结果表明,7种方法所提取的DNA均能满足后续PCR扩增实验的要求。实验室可根据具体的实际情况选择使用DNA提取方法。     

双磁珠法质粒DNA提取技术及应用

质粒是基因合成与测序领域中使用最为频繁的基因运载工具,然而传统的质粒DNA提取方法面临提取通量低、生产成本高等问题,无法满足日益增长的需求。本研究基于质粒提取原理,开发了双磁珠法(double-magnetic-bead method, DMBM)质粒提取技术,探究了磁珠投入量、质粒DNA片段大小、菌液投入量等因素对质粒提取的影响,并且对比了本技术与商业化质粒DNA提取试剂盒提取DNA质量、提取通量及提取成本。结果表明,双磁珠法质粒DNA提取技术可满足不同细胞密度、不同片段长度的质粒DNA提取。此外,该技术搭载96通道全自动核酸提取仪,提取的质粒DNA纯度更高、提取时间缩短80%、提取成本缩减57.1%,从而实现了质粒DNA提取的高通量、低成本,有效助力基因合成与测序。     

四种小鼠肠道微生物DNA提取方法比较

采用异硫氰酸胍(guandine thiocyanate,GITC)法、Tiangen DNA提取试剂盒、Omega DNA提取试剂盒和广泛应用的十六烷基三甲基溴化铵(hexadecyl trimethyl ammonium bromide,CTAB)法提取小鼠粪便微生物总DNA,通过比较所提取DNA的浓度和纯度,发现粪便DNA提取试剂盒提取的DNA纯度最高但浓度最低;CTAB法所得的DNA浓度最高但纯度最低;GITC法所得DNA的浓度高于粪便DNA提取试剂盒,纯度高于CTAB法。通过变性梯度凝胶电泳(16S r DNA-PCR-DGGE)指纹图谱分析技术进一步比较了各种提取方法所代表微生物群落的丰富度和多样性。结果表明,GITC法提取得到的DNA所代表细菌的丰富度和多样性显著高于其他3种方法。本实验所建立的GITC法可更全面地反映肠道微生物的多样性和群落结构,是一种较为理想的粪便微生物DNA提取方法。     

一种改良的植物DNA提取方法

植物组织中含有大量多糖、多酚、酯类等次生代谢产物, 要从中提取高质量的DNA比较困难。针对这一情况, 该文提出一种改良CTAB植物DNA提取方法(mCTAB), 并以10种常见植物为实验材料, 与4种常用的植物DNA提取试剂盒作对比。结果表明, mCTAB法提取的DNA产率高且质量好, PCR扩增成功率也较高, 而提取成本显著低于DNA提取试剂盒, 可有效用于植物DNA条形码等研究的植物DNA提取。     

线粒体DNA序列特点与昆虫系统学研究

昆虫线粒体DNA是昆虫分子系统学研究中应用最为广泛的遗传物质之一。线粒体DNA具有进化速率较核DNA快 ,遗传过程不发生基因重组、倒位、易位等突变 ,并且遵守严格的母系遗传方式等特点。本文概述了mtDNA中的rRNA、tRNA、蛋白编码基因和非编码区的一般属性 ,分析了它们在昆虫分子系统学研究中的应用价值 ,以及应用DNA序列数据来推导分类阶 (单 )元的系统发育关系时 ,基因或DNA片段选择的重要性     

Relative quantification of chrysanthemum yellows (16Sr I) phytoplasma in its plant and insect host using real-time polymerase chain reaction

A real-time polymerase chain reaction (PCR) method for the quantification of chrysanthemum yellows (CY) phytoplasma DNA in its plant (Chrysanthemum carinatum) and insect (Macrosteles quadripunctulatus) host is described. The quantity of CY DNA was measured in each run relative to the amount of host DNA in the sample. Primers and a TaqMan probe for the specific PCR amplification of phytoplasma DNA were designed on a cloned CY-specific ribosomal fragment. Primers and TaqMan probes were also designed on sequences of the internal transcribed spacer region of the insect’s ITS1 rDNA and of the plant’s 18S rDNA for amplification from C. carinatum and M. quadripunculatus, respectively. Absolute quantification of CY DNA was achieved by comparison with a dilution series of the plasmid containing a CY 16S rDNA target sequence. Absolute quantification of plant and insect DNAs was achieved by comparison with a dilution series of the corresponding DNAs. Quantification of CY DNA in relation to host DNA was finally expressed as genome units (GU) of phytoplasma DNA per nanogram of host (plant or insect) DNA. Relative quantification avoided influences due to different yields during the DNA extraction procedure. The quantity of CY DNA was about 10,000–20,000 GU/ng of plant DNA and about 30,000–50,000 GU/ng of insect DNA. The method described could be used to phytoplasma multiplication and movement in different plant and insect hosts.     

线粒体COⅠ基因在昆虫DNA条形码中的研究与应用

自2003年DNA条形码(DNA barcodes)概念出现以来,DNA条形码技术(DNA barcoding)受到生物分类学领域普遍关注,线粒体细胞色素氧化酶亚基I(mtDNACOⅠ)被用作动物类群的主要条形码序列,基于该基因片段的昆虫条形码研究在国内外广泛开展。本文在概述DNA条形码、条形码技术及已开展的昆虫条形码研究计划的基础上,总结了昆虫mtDNACOⅠ条形码及其技术在发现和描述隐种、种类分子鉴定以及系统发育等方面的研究进展,分析了细胞核线粒体假基因(Numts)对mtDNACOⅠ条形码扩增的影响,提出检测和避免Numts的方法,并对DNA条形码技术的进一步研究和应用进行了讨论和展望。     

Evaluation of methods for extracting Xylella fastidiosa DNA from the glassy-winged sharpshooter

The recent spread of the plant pathogenic bacterium Xylclla fastidiosa Wells et al. by an invasive vector species, Homalodisca coagulata Say, in southern California has resulted in new epidemics of Pierce's disease of grapevine. Our goal is to develop an efficient method to detect low titers of X. fastidiosa in H. coagulata that is amenable to large sample sizes for epidemiological studies. Detection of the plant pathogenic bacterium X. fastidiosa in its insect vector is complicated by low titers of bacteria, difficulty in releasing it from the insect mouthparts and foregut, and the presence of substances in the insect that inhibit polymerase chain reaction (PCr). To select the optimal protocol for DNA extraction to be used with PCR, we compared three standard methods and 11 commercially available kits for relative efficiency of X. fastidiosa DNA extraction in the presence of insect tissue. All of the protocols tested were proficient at extracting DNA from pure bacterial culture (1 x 10(5) cells), and all but one protocol successfully extracted sufficient bacterial DNA in the presence of insect tissue. Three DNA extraction techniques, immunomagnetic separation, the DNeasy Tissue kit (Qiagen, Hercules, CA), and Genomic DNA Purification kit (Fermentus, Hanover, MD), were compared more closely using a dilution series of X. fastidiosa (5000-0 cells) with and without insect tissue present. The DNeasy Tissue kit was the best kit tested, allowing detection of 5 x 10(3) X. fastidiosa cells with an insect head background.     

核糖体DNA序列分析在昆虫系统学研究中的应用

随着分子生物学技术的迅速发展,DNA序列分析在昆虫系统学研究中的应用不断增多。本文系统阐述了核糖体DNA的结构、分类学意义、以及在昆虫不同类群不同阶元之间系统发育关系研究中的应用,概要介绍了序列分析方法,并对其应用前景进行了展望。     

基因探针及其在昆虫学上的应用

八十年代以来以基因工程技术为主导的分子生物学研究大大丰富了人们对生命过程和本质的认识。基因工程技术在昆虫学研究中日益受到重视。一个新兴的学科─—昆虫分子生物学已经形成。在分子生物学研究中基因探针是必不可少的重要的工具。由于在系统进化上人和哺乳类遗传距离较近,其基因探针具有较大的通用性,所以医学发展起来的人基因探针为哺乳动物研究带来了许多方便。而无脊椎动物的分子生物学研究一向十分薄弱,因此可用于昆虫的基因探针来源困难,研究者常需在实验设计初期对已有的众多基因探针进行预选或自己制备。所以基因探针的选择和使用对昆虫分子生物学研究至为关键。本文就昆虫学常用的基因探针的类型,标记方法,特别是应用等方面选择若干典型实例作一些介绍和评述。     

Comparative performances of DNA barcoding across insect orders

Background  

Previous studies on insect DNA barcoding provide contradictory results and suggest not consistent performances across orders. This work aims at providing a general evaluation of insect DNA barcoding and "mini-barcoding" by performing simulations on a large database of 15,948 DNA barcodes. We compared the proportions of correctly identified queries across a) six insect orders (Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera and Orthoptera), b) four identification criteria (Best Match: BM; Best Close Match: BCM; All Species Barcodes: ASB; tree-based identification: NJT), and c) reference databases with different taxon coverage (100, 500, 1,000, 1,500 and 1,995 insect species).     

Regularities of the content and organization of pyrimidine oligonucleotide sequences in insect DNA

Certain regularities in content and organization of pyrimidine oligonucleotide sequences of DNA from 15 insect species belonging to 4 orders were studied. The degree of nucleotide clusterization in insect DNA was found to be species-specific, being the highest in Hymenoptera and lowest in Lepidoptera; the Blattodea and Coleoptera occupy an intermediate position by this index between them. The changes in the DNA cluster structure during the evolution of insect species are not of vector type; the degree of clusterization of DNA nucleotide is either increased (Hymenoptera) or decreased (Lepidoptera as compared with Blattodea). In the DNA oligonucleotide fractions containing both pyrimidine nucleotides the percentage content of thymidyl nucleotides is much higher than that of cytidyl nucleotides, the thymine content being increased with the lengthening of oligopyrimidine clusters. The insect species with a higher degree of clusterization of DNA pyrimidine nucleotides contain more thymidyl nucleotide residues. These results agree well with the hypothesis suggesting that during the evolution of large taxons the accumulation of long pyrimidine sequences in animal DNA is accompanied by an increase of thymidyl nucleotide content in them. This can largely be due to the increase of matrix resistance during the evolution and is biologically significant for animals of any taxons, including insects.     

昆虫滞育表观遗传调控的研究进展

滞育是昆虫躲避不良环境的一种策略,对延续昆虫种群具有重要意义。特别是昆虫的兼性滞育,能够受环境的周期性季节变化影响,表观遗传可能在其中扮演重要角色。表观遗传是不依赖DNA序列改变所产生的可遗传变异,包括DNA、RNA、蛋白质和染色质水平上的各种表观遗传调控过程,可能参与生物的发育可塑性。昆虫滞育表观遗传调控主要包括两个方面：一是表观遗传调控如何响应滞育诱导的环境信号;二是环境信号诱导的表观遗传调控如何作用昆虫滞育。尽管已有报道提示DNA甲基化可以响应光周期信号,组蛋白乙酰化能够耦联昆虫内分泌信号,但表观遗传调控参与昆虫滞育的具体机制尚不完全清楚。表观遗传调控昆虫滞育在不同滞育类型的昆虫中都有报道。对于同一滞育类型,不同表观遗传过程之间可能存在协同,这种协同作用如何响应环境信号,又如何精确调节昆虫滞育仍不得而知。总之,现有研究仅仅展示了表观遗传调控昆虫滞育的可能性,昆虫滞育表观遗传调控的分子机制亟待深入研究,特别是以下几个方面：(1)表观遗传响应滞育诱导环境信号的分子机制研究;(2)表观遗传耦联内分泌调控的分子机制研究;(3)介导表观遗传调控的细胞信号转导研究;(4)表观遗传的协同调控在昆虫滞育中的功能研究。     

Mouse DNA primase plays the principal role in determination of permissiveness for polyomavirus DNA replication.

We have investigated the species-specific replication of polyomavirus DNA in the cell-free system that was established previously (Y. Murakami, T. Eki, M. Yamada, C. Prives, and J. Hurwitz, Proc. Natl. Acad. Sci. USA 83:6347-6351, 1986). Extracts from various species of cells supported polyomavirus DNA replication in a species-specific manner that was consistent with the host range specificity of polyomavirus; extracts prepared from mouse and hamster cells were active, whereas extracts prepared from human, monkey, and insect cells were inactive. The addition of DNA polymerase alpha-primase purified from mouse cells induced the replication of polyomavirus DNA in a cell-free system containing polyomavirus large tumor antigen and nonpermissive cell extracts, such as human and insect cell extracts. Isolated mouse DNA primase alone also induced polyomavirus DNA replication in human cell extracts but not in insect cell extracts, indicating that mouse DNA primase plays the principal role in determining permissiveness for polyomavirus DNA replication.