线粒体氧自由基和衰老的研究进展

综述了线粒体作为细胞呼吸和氧化的中心,也是产生氧自由基(ROS)的重要场所,线粒体ROS的产率与衰老的速率呈正相关;ROS能对mtDNA产生氧化伤害导致mtDNA突变,mtDNA突变的增加能加速衰老进程,抗氧化剂和热量限制(CR)都能影响细胞的衰老,但有着不同的机制;最后还讨论自由基导致衰老学说所面临的困难与挑战,展望了对衰老本质的探索。     

动物mtDNA的研究及在鱼类生态学中的应用

概述了动物线粒体的主要特征、动物线粒体DNA(mtDNA)的结构特点、多态和进化；以及线粒体DNA多态研究方法，最后介绍了动物mtDNA的多态性在研究鱼类群体遗传结构上的应用。     

小麦线粒体DNA理化特性的初步研究

对小麦(冀麦七号)线粒体DNA(mtDNA)理化特性的初步研究实验表明,小麦mtDNA由主带(大分子)和小分子群两部分组成。在1×SSC溶液中,对小麦mtDNA的热变性特性进行了分析,其Tm值为86℃,(G+C)％含量为40.8。本实验制备的小麦mtDNA大分子都是线状分子;mtDNA小分子中,主要是线状分子,也有少量的环状分子。mtDNA大分子的分子量为58.02—103.09×10~6道尔顿,线状和环状mtDNA小分子量分别为2.4—11.6×10~6道尔顿和0.4—9.1×10~6道尔顿。     

从微量血中快速制备线粒体DNA片段

目的　建立并鉴定用于从微量血中快速制备线粒体DNA片段的技术 .方法　采用微量血样品 ,改进提取线粒体DNA的方法 ;以不同的方法提取的血DNA为模板 ,同时扩增nDNA上的基因片段和mtDNA上的基因片段 ,PCR相对定量分析比较各种方法提取的mtDNA片段的纯度 ;结果　用华美公司生产的ReadyPCR(tm)微量全血DNA纯化系统和作者的方法都得到了mtDNA ,而用作者的方法获得的mtDNA的纯度较高 ;结论　由于线粒体DNA与核DNA存在有同源片段 ,ReadyPCR(tm)微量全血DNA纯化系统和常规酶解法提取DNA不适合用于对mtDNA的鉴定 ,作者的方法简便快捷地排除了核DNA的污染 ,非常适合于对mtDNA进行PCR分析 .     

线粒体与衰老研究进展

目的：研究线粒体与衰老的关系。方法：通过查阅大量的国内外相关文献综述。结果：线粒体数量的变化。结构功能的退化，氧自由基对线粒体的损伤以及mtDNA的突变对衰老有着重要的影响。结论：线粒体影响衰老的机制复杂，从多方面影响衰老。     

一种四膜虫线粒体DNA提取的新方法

本文根据四膜虫线粒体DNA（mtDNA）对碱稳定这一特性，建立了一种更为简便的，能直接提取四膜虫线粒体DNA的方法。该方法快速简便，重复性好，可用于游离细胞材料mtDNA的提取。     

光肩星天牛及其近缘种mtDNA序列和基因特点

通过对光肩星天牛及其近缘种mtDNA的7个基因片段的测序，分析了光肩星天牛mtDNA的特点。结果表明，所测的光肩星天牛mtDNA7个基因序列与其近缘种差异达11．3％以上，光肩星天牛种群及个体间碱基差异小于3％，大部分基因基本没有差异，光肩星天牛mtDNA的这一特点说明这些基因在种内较为保守，可用于该虫的鉴定和系统遗传分析；光肩星天牛与黄斑星天牛在这些基因上差异很小，有可能为同一个种。在COI，Cytb等基因测序中，发现部分个体出现差异大的序列，有的为其近缘种基因。     

四君子汤对D-半乳糖诱致衰老小鼠脑抗氧化能力和线粒体DNA(mtDNA)损伤的影响

目的 探讨四君子汤(Sijunzi decoction,SJZ)对D-半乳糖诱致衰老小鼠脑抗氧化能力和线粒体DNA(mtDNA)损伤的影响.方法 给小鼠连续皮下注射D-半乳糖(1000 ms/(kg·d-1))8周制备衰老模型,并于第3周开始给予四君子汤高剂量组(20 g/kg)、中剂量组(10 g/kg)、低剂量组(5 g/kg)和维生素E(250 ms/kg)处理;8周后采用水迷宫测定小鼠学习记忆能力;采用比色法测定脑组织谷胱甘肽过氧化物酶(GSH-Px)和琥珀酸脱氢酶(SDH)的活力;Fura-2/AM双波长荧光法检测海马神经细胞钙离子浓度;常规PCR检测小鼠海马细胞mtDNA缺失突变.结果 四君子汤可明显改善模型小鼠的学习和记忆能力,并提高脑组织GSH-PX和SDH的活力,降低脑细胞内钙离子浓度,防止模型小鼠脑海马细胞mtDNA缺失突变.结论 四君子汤具有改善D-半乳糖诱致小鼠学习记忆障碍的作用,其作用与其提高脑组织抗氧化能力,降低海马胞内钙离子浓度,减轻细胞线粒体DNA缺失突变的作用有关.     

茄子雄性不育株和可育株的胞质DNA和核DNA差异分析

以茄子(Solanum melongenaL)雄性不育株“正兴1号”(S)和可育株(F)的总DNA为模板,对60个随机引物进行了筛选,找到5个其RAPD(Random amplified polymorphic DNA,RAPD)扩增产物在茄子雄性不育系和对照材料间存在稳定差异的引物．将该5个引物同时扩增总DNA、核DNA和线粒体DNA(mitochondrial DNA,mtDNA)．以总DNA为模板时得到多态性片段9个,以核DNA为模板时得到5个,以mtDNA为模板时得到9个．以总DNA为模板时得到的9个扩增片段中,有5个在总DNA和mtDNA中同时出现,而在核中没有出现,即认为来自mtDNA,这5个片段中,有4个来自可育株,1个来自不育株,说明不育株和可育株在mtDNA上存在差异;有4个片段同时出现在以总DNA和核DNA为模板的扩增中,但在以mtDNA为模板的扩增中却没有出现,认为是来自核DNA,这4个片段中,有3个来自不育株,一个来自可育株,说明可育株和不育株在核DNA上也存在差异．结果初步表明：新发现的茄子雄性不育可能是核质相互作用所引起．     

两种优化的提纯鱼类线粒体DNA的方法

以鱼类的卵巢、肝脏为材料，采用两种方法制备并纯化了线粒体DNA（mtDNA），并进行了琼脂糖电泳检查。结果表明，两种方法都能获取高浓度的mtDNA样品，且收得率都较高。     

Deletions of muscle mitochondrial DNA in patients with mitochondrial myopathies

In vitro studies of muscle mitochondrial metabolism in patients with mitochondrial myopathy have identified a variety of functional defects of the mitochondrial respiratory chain, predominantly affecting complex I (NADH-CoQ reductase) or complex III (ubiquinol-cytochrome c reductase) in adult cases. These two enzymes consist of approximately 36 subunits, eight of which are encoded by mitochondrial DNA (mtDNA). The increased incidence of maternal, as opposed to paternal, transmission in familial mitochondrial myopathy suggests that these disorders may be caused by mutations of mtDNA. Multiple restriction endonuclease analysis of leukocyte mtDNA from patients with the disease, and their relatives, showed no differences in cleavage patterns between affected and unaffected individuals in any single maternal line. When muscle mtDNA was studied, nine of 25 patients were found to have two populations of muscle mtDNA, one of which had deletions of up to 7 kilobases in length. These observations demonstrate that mtDNA heteroplasmy can occur in man and that human disease may be associated with defects of the mitochondrial genome.     

An autosomal dominant disorder with multiple deletions of mitochondrial DNA starting at the D-loop region

Deletions of muscle mitochondrial DNA (mtDNA) have recently been found in patients with mitochondrial myopathy. However, as most of the described cases were sporadic, and individual deletions involved different portions of mtDNA, the mechanism(s) producing the molecular lesions, as well as their mode of transmission, remain unclear. By studying families with mtDNA heteroplasmy, valuable information can be obtained about the role of inheritable factors in the pathogenesis of these disorders. We have studied four members of a family with autosomal dominant mitochondrial myopathy. Multiple deletions, involving the same portion of muscle mtDNA, were identified in all patients. Sequence analysis of the mutant mtDNAs, performed after DNA amplification by the polymerase-chain reaction showed that all the deletions start within a 12-nucleotide stretch at the 5' end of the D-loop region, a site of active communication between the nucleus and the mtDNA. The data indicate that a mutation of a nuclear-coded protein can destroy the integrity of the mitochondrial genome in a specific, heritable way.     

线粒体与人类疾病

线粒体自身携带DNA，可自我复制、表达。研究表明，线粒体DNA突变的积累和氧化损伤与人类疾病、衰老和肿瘤密切相关。     

Premature ageing in mice expressing defective mitochondrial DNA polymerase

Point mutations and deletions of mitochondrial DNA (mtDNA) accumulate in a variety of tissues during ageing in humans, monkeys and rodents. These mutations are unevenly distributed and can accumulate clonally in certain cells, causing a mosaic pattern of respiratory chain deficiency in tissues such as heart, skeletal muscle and brain. In terms of the ageing process, their possible causative effects have been intensely debated because of their low abundance and purely correlative connection with ageing. We have now addressed this question experimentally by creating homozygous knock-in mice that express a proof-reading-deficient version of PolgA, the nucleus-encoded catalytic subunit of mtDNA polymerase. Here we show that the knock-in mice develop an mtDNA mutator phenotype with a threefold to fivefold increase in the levels of point mutations, as well as increased amounts of deleted mtDNA. This increase in somatic mtDNA mutations is associated with reduced lifespan and premature onset of ageing-related phenotypes such as weight loss, reduced subcutaneous fat, alopecia (hair loss), kyphosis (curvature of the spine), osteoporosis, anaemia, reduced fertility and heart enlargement. Our results thus provide a causative link between mtDNA mutations and ageing phenotypes in mammals.     

Mitochondrial genome variation and the origin of modern humans

The analysis of mitochondrial DNA (mtDNA) has been a potent tool in our understanding of human evolution, owing to characteristics such as high copy number, apparent lack of recombination, high substitution rate and maternal mode of inheritance. However, almost all studies of human evolution based on mtDNA sequencing have been confined to the control region, which constitutes less than 7% of the mitochondrial genome. These studies are complicated by the extreme variation in substitution rate between sites, and the consequence of parallel mutations causing difficulties in the estimation of genetic distance and making phylogenetic inferences questionable. Most comprehensive studies of the human mitochondrial molecule have been carried out through restriction-fragment length polymorphism analysis, providing data that are ill suited to estimations of mutation rate and therefore the timing of evolutionary events. Here, to improve the information obtained from the mitochondrial molecule for studies of human evolution, we describe the global mtDNA diversity in humans based on analyses of the complete mtDNA sequence of 53 humans of diverse origins. Our mtDNA data, in comparison with those of a parallel study of the Xq13.3 region in the same individuals, provide a concurrent view on human evolution with respect to the age of modern humans.     

内蒙古砧子山墓地古人的线粒体DNA多态性分析

为了研究内蒙古元上都遗址砧子山墓地古代人群的遗传结构及其可能来源,对该墓地古人的DNA进行了抽提、扩增和测序,获得了10个个体的线粒体DNA高可变一区序列.结合现代东亚、北亚、中亚和欧洲人的线粒体DNA数据进行了系统发育分析和多维尺度分析.研究结果表明:埋藏在砧子山墓地的元代居民为汉族人,主要是来自中国北方地区的汉族.本研究为揭示元代的复杂社会结构和人群历史动态提供了新的方法.     

秀丽线虫sod-3基因RNA干扰及早衰模型的建立

利用RNAi技术， 通过干扰秀丽线虫中的sod-3基因表达， 建立了因超氧化物歧化酶3（SOD3）表达缺失引起快速衰老的线虫模型，为sod-3 基因功能的研究以及相关疾病的基因治疗等提供动物模型.     

云南大理白族和汉族弱精子症患者精子mtDNA 4977 bp缺失相关性研究

探讨云南大理白族和汉族弱精子症患者精子线粒体DNA(mtDNA) 4977 bp缺失的相关性。收集云南大理白族弱精子症患者137例,汉族弱精子症患者121例,正常对照组大理白族和白族精子活力正常人各120例,提取精液基因组DNA,采用聚合酶链式反应(PCR)技术进行精子mtDNA4977bp缺失的研究。结果显示,120例正常对照的大理白族精子活力正常人中有10例(8.33%)存在mtDNA4977 bp缺失;而137例大理白族弱精子症患者中有89例(64.96%)存在mtDNA 4977 bp缺失。两组4977 bp缺失频率比较有极显著性差异(P 0.01)。120例正常对照的汉族精子活力正常人中有7例(5.83%)存在mtDNA 4977 bp缺失;121例大理白族弱精子症患者中有85例(70.25%)存在mtDNA 4977 bp缺失。两组4977 bp缺失频率比较差异有极显著性(P 0.01)。同时发现大理白族弱精子症患者与汉族弱精子症患者mtDNA 4977 bp缺失频率无显著性差异(P 0.05)。大理白族和汉族人群mt DNA 4977 bp缺失与弱精子症的发病有明显的关联,提示mtDNA 4977 bp缺失在弱精子症的发生中可能起重要作用。