线粒体DNA标记在昆虫学研究中的应用进展

综述了昆虫线粒体DNA（mtDNA）的特点、mtDNA标记优缺点及该标记在昆虫学研究中的应用。目前应用mtDNA作分子遗传标记主要用来进行昆虫分类单元的鉴定、物种或种群的系统发育、遗传多样性、基因流、起源及杂交带的研究,但由于mtDNA标记的缺点,因此常需与其他标记技术结合使用才能获得更可靠的结果。     

鞘翅目昆虫线粒体DNA多态性研究进展

线粒体DNA(mtDNA)是真核细胞中分子量较小而又较易纯化的复制单位，因其遗传结构简单，遵守严格的母系遗传方式，且进化速率较核DNA快，无重组现象等特点，目前已成为分子系统学研究中应用仅次于mtDNA的分子。本文对鞘翅目昆虫mtDNA多态性的研究进行综述，根据1990年-2002年的相关资料，表明mtDNA在鞘翅目昆虫系统学研究中应用广泛，共涉及14科37属200多种。mtDNA在近缘种的分类、种间及种内系统发生关系。种群的起源、分化及群体遗传学等研究中有着十分重要的意义。     

鞘翅目昆虫线粒体DNA多态性研究进展

线粒体DNA(mtDNA)是真核细胞中分子量较小而又较易纯化的复制单位,因其遗传结构简单,遵守严格的母系遗传方式,且进化速率较核DNA 快,无重组现象等特点,目前已成为分子系统学研究中应用仅次于rDNA的分子.本文对鞘翅目昆虫mtDNA多态性的研究进行综述,根据1990年～2002年的相关资料,表明mtDNA 在鞘翅目昆虫系统学研究中应用广泛,共涉及14科37属200多种.mtDNA在近缘种的分类、种间及种内系统发生关系,种群的起源、分化及群体遗传学等研究中有着十分重要的意义.     

rDNA和mtDNA在昆虫系统发育与区系研究中的应用

核酸序列分析技术在昆虫系统发育与区系研究中的应用较为广泛。根据近期国内外的研究,详述核糖体DNA(rDNA)序列,线粒体DNA(mtDNA)序列以及其他较保守基因序列在昆虫系统发育与区系研究中的应用。     

蝗虫线粒体DNA(mtDNA)研究概况

线粒体DNA（mtDNA）具有快速进化、不易发生突变等独特的优点，正成为昆虫系统发育、种群遗传变异与分化研究和近缘种、种下分类单元鉴定的理想工具之一。文中介绍了应用线粒体DNA研究蝗虫物种起源与分化、系统发育、遗传多样性及体色分化等方面的进展概况。     

动物线粒体基因分子系统学研究进展

分析了动物线粒体DNA的结构特点和基因成分 ,并就动物线粒体DNA的分子系统学及其研究方向进行了简要综述 ;同时 ,对绢丝昆虫线粒体基因组研究进展进行了阐述     

昆虫线粒体DNA在分子进化研究中的应用

阐述了昆虫线粒体DNA在分子进化中的研究进展,包括昆虫线粒体DNA的组成和各部分的进化特点,以及线粒体DNA在昆虫系统学中的应用情况,并对今后的深入研究提出了建议。     

DNA条码技术在上海辰山植物园10种灯诱夜蛾科昆虫种类鉴定中的应用

为检验DNA条码技术在鳞翅目夜蛾科昆虫种类鉴定中的应用效果,通过提取43条上海辰山植物园夜蛾科昆虫的基因组DNA,并通过PCR扩增线粒体细胞色素氧化酶I(COI)序列进行Blast分析,计算种间遗传距离和种内遗传距离,并采用邻接法构建系统发育树。结果表明,43个鳞翅目夜蛾科昆虫样本属于10个种,种间遗传距离介于0.069 8～0.116 3之间,种内遗传距离介于0～0.001 5之间,二者之间并未重叠;聚类分析表明,同种和不同种类昆虫分别在系统发育树上形成同一进化支和独立的多条进化分支。因此,DNA条码技术可作为辅助工具,应用于鳞翅目夜蛾科昆虫种类鉴定。     

苹果绵蚜线粒体DNA的提取方法研究简报

 获得高质量的线粒体DNA（mtDNA）是进行mtDNA研究的前提。本研究用碱裂解法和加热法均得到了满足RFLP分析要求的苹果绵蚜mtDNA。但只有碱裂解法提取的mtDNA满足克隆的需要。经分析认为,在实验过程中尽可能的避免核DNA的断裂,是获取高质量mtDNA的关键。     

基于COⅠ基因对卷蛾科昆虫的分子系统发育关系研究

目前,对于检疫截获昆虫的鉴定大都采用形态学的方法,传统的昆虫形态学鉴定方法存在一定的缺陷,例如大多数昆虫的形态鉴定是以完整的成虫为研究对象,而昆虫的早期(卵、幼虫和蛹)形态结构与肢体残缺的虫体均很难辩认,鉴定非常困难。DNA是遗传信息的载体,直接从DNA上得到的信息是最准确、最可靠的,因此DNA条形码技术可以解决传统昆虫形态学鉴定的这一缺陷。鳞翅目是昆虫中利用DNA条形码研究最多的目,分析卷蛾科22种昆虫29条线粒体COⅠ基因及其遗传进化距离,讨论DNA条形码技术在检疫性蛾类昆虫鉴定应用中的可行性。     

Mitochondrial DNA mutations, oxidative stress, and apoptosis in mammalian aging

Mutations in mitochondrial DNA (mtDNA) accumulate in tissues of mammalian species and have been hypothesized to contribute to aging. We show that mice expressing a proofreading-deficient version of the mitochondrial DNA polymerase g (POLG) accumulate mtDNA mutations and display features of accelerated aging. Accumulation of mtDNA mutations was not associated with increased markers of oxidative stress or a defect in cellular proliferation, but was correlated with the induction of apoptotic markers, particularly in tissues characterized by rapid cellular turnover. The levels of apoptotic markers were also found to increase during aging in normal mice. Thus, accumulation of mtDNA mutations that promote apoptosis may be a central mechanism driving mammalian aging.     

榨菜线粒体DNA的提取

利用蔗糖衬垫法从榨菜胞质雄性不育系及保持系中分离出了线粒体DNA,琼脂糖凝胶电泳及紫外分光光度分析表明,所提取的DNA可用于后续的研究工作,即作为PCR模板,进行榨菜胞质雄性不育相关特异片段扩增及RAPD。     

ROS-generating mitochondrial DNA mutations can regulate tumor cell metastasis

Mutations in mitochondrial DNA (mtDNA) occur at high frequency in human tumors, but whether these mutations alter tumor cell behavior has been unclear. We used cytoplasmic hybrid (cybrid) technology to replace the endogenous mtDNA in a mouse tumor cell line that was poorly metastatic with mtDNA from a cell line that was highly metastatic, and vice versa. Using assays of metastasis in mice, we found that the recipient tumor cells acquired the metastatic potential of the transferred mtDNA. The mtDNA conferring high metastatic potential contained G13997A and 13885insC mutations in the gene encoding NADH (reduced form of nicotinamide adenine dinucleotide) dehydrogenase subunit 6 (ND6). These mutations produced a deficiency in respiratory complex I activity and were associated with overproduction of reactive oxygen species (ROS). Pretreatment of the highly metastatic tumor cells with ROS scavengers suppressed their metastatic potential in mice. These results indicate that mtDNA mutations can contribute to tumor progression by enhancing the metastatic potential of tumor cells.     

Discovery of a major D-loop replication origin reveals two modes of human mtDNA synthesis

Mammalian mitochondrial DNA (mtDNA) replication has long been considered to occur by asymmetric synthesis of the two strands, starting at the multiple origins of the strand-displacement loop (D-loop). We report the discovery of a major replication origin at position 57 in the D-loop of several human cell lines (HeLa, A549, and 143B.TK-) and immortalized lymphocytes. The nascent chains starting at this origin, in contrast to those initiated at the previously described origins, do not terminate prematurely at the 3' end of the D-loop but proceed well beyond this control point, behaving as "true" replicating strands. This origin is mainly responsible for mtDNA maintenance under steady-state conditions, whereas mtDNA synthesis from the formerly identified D-loop origins may be more important for recovery after mtDNA depletion and for accelerating mtDNA replication in response to physiological demands.     

松毛虫mtDNA PCR反应体系优化

为了应用线粒体DNA研究松毛虫种群的遗传结构,本研究采用正交试验设计法L16(45)对影响松毛虫mtDNA PCR反应体系的5个因素(Taq酶、Mg2+、模板DNA、dNTP、引物)在4个水平上进行优化试验并对PCR扩增程序中的退火温度及循环次数进行了单因素梯度比较优化。建立了松毛虫mtDNA PCR反应的最佳体系即在50μL体系中含模板150 ng、0.10μmol/L引物、0.4 mmol/L dNTP、1.0UTaq DNA聚合酶、2.5 mmol/LMg2+。同时通过PCR比较,确定最佳循环次数为35个循环,最佳退火温度为56℃,获得了松毛虫mtDNA PCR反应的最佳扩增程序。     

黔北一新鱼种遵义小钝吻鮠线粒体DNA的分离纯化

用差速离心法和改进的碱裂解法分离纯化遵义小钝吻鮠线粒体DNA,紫外检测其OD260/OD280在1.78～1.85,并计算出该鱼肝组织线粒体DNA的含量为0.613μg/g。纯化样品经紫外分析仪在200～290 nm波长范围内扫描,呈现典型的DNA吸收峰,其最大吸收峰在259～260 nm。以λDNA/HindⅢ的完全酶切片段作为相对分子量标准,利用电泳迁移率与分子量的对数的线性关系,由已知片段大小推算出遵义小钝吻鮠mtDNA分子大小为(15.44±0.16)kb。     

Method for Isolating Mitochondrial DNA from Etiolated Tissue of Cabbage

Isolation of high-quality mitochondrial DNA（mtDNA） is an important premise for researching molecular mechanisms in cytoplasmic male sterility of cabbage（Brassica oleracea L.var.capitata）. An efficient protocol for separation and purification of mitochondria and extraction of mitochondrial DNA（mtDNA） from etiolated tissues of cabbage was developed. We took a method combined mannitol density gradient with differential centrifugation, selected appropriate rotational speed, extended DNase I treating time and changed mitochondria cracking condition. The results showed that the extracted mitochondria in this protocol had complete structure, appeared to ellipsoid and had not been contaminated with other impurities under the Jannus Green B staining. The isolated mitochondrial DNA had high purity and yield through detecting the optical density, nuclear specific primer PCR and agarose gel electrophoresis. The results indicated that mitochondrial DNA extracted by this protocol had high quality and enabled to be used in futher genetic studies.     

Facile detection of mitochondrial DNA mutations in tumors and bodily fluids

Examination of human bladder, head and neck, and lung primary tumors revealed a high frequency of mitochondrial DNA (mtDNA) mutations. The majority of these somatic mutations were homoplasmic in nature, indicating that the mutant mtDNA became dominant in tumor cells. The mutated mtDNA was readily detectable in paired bodily fluids from each type of cancer and was 19 to 220 times as abundant as mutated nuclear p53 DNA. By virtue of their clonal nature and high copy number, mitochondrial mutations may provide a powerful molecular marker for noninvasive detection of cancer.