Restriction map and clone bank of tomato plastid DNA

Summary Tomato plastid DNA has been isolated from leaf chloroplasts andPst1 fragments cloned in the plasmid vector pUC8. Recombinant plasmids containing all but the largestPst1 fragment were identified by colony hybridisation. A restriction map of the plastid DNA for four restriction endonucleases was generated by digestion of the clonedPst1 fragments and by hybridisation to Southern blots. The plastid DNA is a circular molecule of 156.6–159.4 kbp with a large inverted repeat, and shows high conservation of restriction sites with plastid DNA from tobacco andPetunia.     

Molecular analysis of mitochondrial DNA and its inheritance in Epilobium

Summary The mitochondrial genome of four Epilobium species has been characterized by restriction analysis and hybridizations with gene probes from Oenothera. Mitochondrial DNA of Epilobium has a complex restriction fragment pattern and an estimated size of about 320 kb. All species exhibit specific restriction patterns. Plasmid-like DNA molecules of 0.3 kb to 1.2 kb are found in preparations of undigested nucleic acids of mitochondria from E. montanum, E. watsonii, and E. lanceolatum. In contrast, the mitochondria of E. hirsutum contain double-stranded RNAs of 2.7 kb. The location of the genes for cytochrome c oxidase subunits I and III on the mitochondrial DNA seems to be conserved in those species analyzed. However, the genes for subunit II of this complex, and for the alpha subunit of ATPase, are located on different restriction fragments in the mitochondrial genomes of certain species. The location of the COX II gene on different BamHI fragments in E. watsonii and E. lanceolatum has been used for the analysis of mitochondrial inheritance in reciprocal hybrids. Like the plastids, mitochondria are inherited maternally in Epilobium.Abbreviations kb kilobase pairs - mtDNA mitochondrial DNA     

线粒体肌病患者线粒体DNA的突变分析

目的分析线粒体肌病患者线粒体DNA的突变情况，为疾病诊断提供依据。方法用常规HE、酶组化染色和电镜检查等病理形态学方法对3例线粒体肌病疑似患者进行诊断，并用聚合酶链反应-单链构象多态和DNA测序等方法对患者线粒体DNA中全部22个tRNA基因进行突变筛查。结果3例患者均被确诊为线粒体肌病，其中例1tRNA—VaI基因发生A1627G纯合突变，例2tRNA—Val基因发生A1627G／A杂合突变，例3tRNA—Trp基因发生T5554C突变、tRNA—Arg基因发生A10412C／A杂合突变。结论线粒体DNA中的tRNA基因突变是线粒体肌病的重要病因之一。     

The organization of repeating units in mitochondrial DNA from yeast petite mutants

Summary We have reinvestigated the linkage orientation of repeating units in mtDNAs of yeast ^– petite mutants containing an inverted duplication. All five petite mtDNAs studied contain a continuous segment of wild-type mtDNA, part of which is duplicated and present in inverted form in the repeat. We show by restriction enzyme analysis that the non-duplicated segments between the inverted duplications are present in random orientation in all five petite mtDNAs. There is no segregation of sub-types with unique orientation. We attribute this to the high rate of intramolecular recombination between the inverted duplications. The results provide additional evidence for the high rate of recombination of yeast mtDNA even in haploid ^– petite cells.We conclude that only two types of stable sequence organization exist in petite mtDNA: petites without an inverted duplication have repeats linked in straight head-to-tail arrangement (abcabc); petites with an inverted duplication have repeats in which the non-duplicated segments are present in random orientation.     

Restriction enzyme analysis of mitochondrial DNA in aging human cells

Human diploid fibroblasts show a limited lifespan in vitro. To investigate the integrity of mitochondrial DNA (mtDNA) in aging fibroblasts, whole cell DNA samples from the human cell line IMR-90 have been prepared at 36, 22, and 3 population doublings (PD) from the end of the lifespan (63 PD). These DNA samples were then digested separately with 19 different restriction endonucleases, and the resulting fragments were separated by agarose gel electrophoresis and transferred to nitrocellulose filters. Fragment sizes were revealed by hybridization to 32P-labelled mouse mtDNA and autoradiography, and were compared with computer maps of fragments generated from the known sequence of human mtDNA. These 19 enzymes recognize a total of 297 recognition sites comprising 1315 nucleotide base pairs (bp), approximately 8% of the human mtDNA (16 569 bp). Control experiments reveal that a minor component representing as little as 5% of the total mtDNA can be detected. No changes were seen in the restriction fragment pattern with fibroblast cell age. It is concluded that there are no large deletions, insertions, or rearrangements in human mtDNA, and no single base changes in the detectable regions. This suggests efficient maintenance of mtDNA molecules and/or elimination of damaged mtDNA during fibroblast cell lifespan.     

Autoradiographic study of cell cultures

Department of Pathological Anatomy, A. V. Vishnevskii Institute of Surgery, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR D. S. Sarkisov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 110, No. 12, pp. 659–661, December, 1990.     

日本血吸虫线粒体大亚基核糖体基因的亚克隆、测序及同源性分析

目的将筛选日本血吸虫成虫cDNA文库得到基因克隆并测序。方法体外将以阳性克隆为模板的PCR产物和 pGEM T载体连接 ,转化大肠杆菌XL1 blue,经抗生素及生色底物X gal初筛 ,再用限制性内切酶酶切法进一步鉴定和用DNA自动测序仪测序。序列送blast基因服务站进行同源性分析。结果构建了3个含日本血吸虫cDNA基因片段的重组子 ,其中1个阳性克隆序列为编码日本血吸虫线粒体大亚基核糖体rRNA的基因序列 ,另2个序列与已知的日本血吸虫基因序列无同源性。结论获得了日本血吸虫线粒体大亚基核糖体rRNA基因片段 ,为进一步分析其一级结构和功能打下了基础。     

Oxidized mitochondrial DNA sensing by STING signaling promotes the antitumor effect of an irradiated immunogenic cancer cell vaccine

Exposure to ionizing radiation, a physical treatment that inactivates live tumor cells, has been extensively applied to enhance the antitumor responses induced by cancer cell vaccines in both animal research and human clinical trials. However, the mechanisms by which irradiated cells function as immunogenic tumor vaccines and induce effective antitumor responses have not been fully explored. Here, we demonstrate that oxidized mitochondrial DNA (mtDNA) and stimulator of interferon genes (STING) signaling play a key roles in the enhanced antitumor effect achieved with an irradiated tumor cell vaccine. Elevations in ROS and oxidized mtDNA 8-OHG content could be induced in irradiated tumor cells. Oxidized mtDNA derived from irradiated tumor cells gained access to the cytosol of dendritic cells (DCs). Oxidized mtDNA, as a DAMP or adjuvant, activated the STING-TBK1-IRF3-IFN-β pathway in DCs, which subsequently cross-presented irradiated tumor cell-derived antigens to CD8⁺ T cells and elicited antitumor immunity. The results of our study provide insight into the mechanism by which an irradiated cell vaccine mediates antitumor immunity, which may have implications for new strategies to improve the efficacy of irradiated vaccines.     

A detailed restriction endonuclease cleavage map of rat liver mitochondrial DNA

Summary A restriction endonuclease cleavage map of rat liver mitochondrial DNA is presented for the following enzymes: Xba I, Bgl II, Hae II, Bam HI, Hpa I, Hha I, Bcl I, Hind II, Hind III, Eco RI, Hpa II, Hae III, and Sau 3A. It was derived from complete and partial digestions with these enzymes, double digestions, and redigestions of defined fragments obtained with one enzyme with other restriction enzymes. By the use of these and further enzymes (Taq YI, Alu I) the mitochondrial DNA (ca. 15.6 Kb) can be dissected into a large number of defined fragments.Abbreviations mtDNA mitochondrial DNA - bp or Kbp base pairs or kilo base pairs     

Wheat mitochondrial 26S ribosomal RNA gene has no intron and is present in multiple copies arising by recombination

Summary Analysis of cloned SalI fragments coding for the 26S rRNA in wheat mitochondria (Triticumaestivum L.) shows that the 26S gene is contained within the same basic structural unit RS (which is about 6.6 kbp long). This repeated sequence is flanked by four different sequences I, II, III, IV in the orientations: I-RS-III, I-RS-IV, II-RS-III and II-RS-IV. This organization of the 26S gene, similar to the organization found for the 5S and 18S gene, suggests again that reciprocal intra-and/or intermolecular recombination occurs within these repeated sequences. S1 mapping and R loop mapping indicate that the 26S gene is about 3.5 kbp and has no intron.     

MITOMASTER: a bioinformatics tool for the analysis of mitochondrial DNA sequences

We have developed a computer system, MITOMASTER, to make analysis of human mitochondrial DNA (mtDNA) sequences efficient, accurate, and easily available. From imported sequences, the system identifies nucleotide variants, determines the haplogroup, rules out possible pseudogene contamination, identifies novel DNA sequence variants, and evaluates the potential biological significance of each variant. This system should be beneficial for mtDNA analyses of biomedical physicians and investigators, population biologists and forensic scientists. MITOMASTER can be accessed at http://mammag.web.uci.edu/twiki/bin/view/Mitomaster.     

Mitochondrial and chromosomal DNA alterations in human chromophobe renal cell carcinomas.

Renal cell tumours are characterized by the loss of chromosome 3p and trisomy of 5q segments (common, non-papillary renal cell carcinoma), or by trisomy of chromosomes 7 and 17 and loss of the Y chromosome (papillary renal cell carcinoma), or by random karyotype changes and mitochondrial DNA alterations (renal oncocytoma). We have studied by means of RFLP analysis the genomic and mitochondrial DNA in 11 chromophobe renal cell carcinomas, which have a unique morphology among kidney cancers. We found a loss of the constitutional heterozygosity at chromosomal regions 3p, 5q, 17p, and 17q, a combination of allelic losses that has not been found in other types of renal cell tumours. Three of the tumours showed a gross alteration in the restriction pattern of the mitochondrial DNA. A combined morphological and genetic analysis suggests that chromophobe renal cell carcinoma is a distinct entity.     

病毒性心肌炎小鼠心肌细胞线粒体DNA缺失的定量分析

目的：探讨线粒体DNA(mtDNA)缺失在病毒性心肌炎(VMC)发病机制中的作用。 方法： 50只BALB/c小鼠随机分为2组，实验组(40只) 腹腔注射内含CVB3(TCID50＝108)的Eagle液制备VMC小鼠模型，另10只为对照组。分别于病毒感染后第3、11和24 d行在体心功能和心肌细胞mtDNA3867缺失率测定，并用Spearman法对mtDNA3867缺失率及心功能测值行相关分析。 结果： 实验组小鼠病毒感染后第3 d心肌细胞mtDNA3867缺失率比对照组高8.3倍［(0.01970±0.00118)% vs (0.00211±0.00032)%，P＜0.05］，同时可见其-dp/dtmax亦显著高于对照组(P＜0.05)；病毒感染后第11 d时，mtDNA3867缺失率比对照组高14.6倍［(0.03292±0.00308)% vs (0.00211±0.00032)%，P＜0.05］，心脏的收缩(LVPSP、+dp/dtmax)和舒张功能(-dp/dtmax)亦有更显著损伤(均P＜0.05)；病毒感染后第24 d时，mtDNA3867缺失率仍显著高于对照组，比后者高11.5倍，其心功能亦未恢复正常。相关分析显示，mtDNA3867缺失率与LVPSP和+dp/dtmax呈显著负相关，与-dp/dtmax呈显著正相关，相关系数分别为－0.66、－0.79和0.80(均P＜0.05)。 结论： mtDNA3867缺失可能是VMC发病的病理生理机制之一。     

Association between mitochondrial DNA copy number, blood cell counts, and occupational benzene exposure

Benzene is a recognized hematotoxicant and carcinogen that produces genotoxic damage. Benzene metabolites can produce reactive oxidative species. Mitochondrial DNA (mtDNA) copy number may be increased in response to oxidative stress to compensate for damaged mitochondria. We carried out a cross-sectional study of 40 benzene-exposed workers and 40 controls to evaluate the association between benzene exposure and mtDNA copy number. Copy number of mtDNA in leukocyte DNA was determined by real-time PCR. Compared with controls, the copy number of mtDNA increased by 4% and by 15% in workers exposed to < or =10 ppm (n = 20) and >10 ppm (n = 20) benzene, respectively. After adjusting for recent infection, the factor that was significantly correlated with mtDNA, the increase of mtDNA was statistically significant in the high exposed group (P = 0.016) with a significant linear trend (P = 0.024). To our best knowledge, this is the first report that benzene exposure was associated with increased mitochondria DNA copy number. Benzene exposure may induce mtDNA amplification, possibly in response to oxidative stress caused by benzene. The finding needs to be replicated by other studies.     

遗传性共济失调一家系中发现的线粒体DNA突变

目的探索遗传性共济失调（hereditary ataxia，HA）家系中的线粒体DNA突变。方法采用聚合酶链反应扩增两个HA家系及35名健康对照者外周血白细胞的线粒体DNA，并对PCR产物进行单链构象多态性分析，对出现异常条带者进行线粒体DNA片段测序。结果其中一家系中的2例患者及1例无临床症状亲属检测到线粒体DNA11893（A→G）点突变。结论遗传性共济失调的发生、发展可能与线粒体DNA11893（A→G）点突变有关。     

Development of primary cell cultures from Nephrops norvegicus

This paper reports the first attempt to develop primary cell cultures from tissues (ovary, testes, hepatopancreas, haematopoietic tissue, heart, gut, gill, eye-stalk and nerve tissues) of the Dublin Bay prawn (also known as the Norwegian squat lobster and scampi) Nephrops norvegicus (L.) using Leibovitz's L-15, MEM and M199 media supplemented with 5, 10 or 20 percent (w/v) foetal bovine serum (FBS). The best results were achieved with ovary tissues in 2× Leibovitz's L-15. Also, primary cell cultures were developed with testicular and haematopoietic tissues. With ovary tissues, results with 5 percent (w/v) FBS at an osmolality of 800 mOsm/kg were superior for the maintenance of epithelial-type cells, and enabled longer survival, i.e. more than 3 months. Little success was achieved with M199 and MEM media. One subculture of ovary cells was obtained.     

Genetic map of mitochondrial DNA in Podospora anserina

Summary In order to develop an eukaryotic vector with the Podospora plasmid, further characterization is required of the mitochondrial DNA into which this plasmid is integrated, a physical map (restriction sites) of the Podospora chondriome (size 95 kb) has been completed. As prerequisite for the establishment of a genetic (functional) map, 70% of the chondriome was cloned in E. coli vectors. Using mitochondrial genes from Saccharomyces cerevisiae, six structural genes were located on the Podospora chondriome by cross hybridization experiments. There is strong evidence that the plasmid is inserted into the cytochrome b gene. A comparison of the genetic map of the Podospora chondriome with those of Neurospora crassa and Aspergillus nidulans exhibits a rather good accordance with respect to the sequence of genes.     

The mitochondrial genome of Nicotinia plumbaginifolia

Summary DNA was isolated from DNase-treated, osmotically shocked mitochondria from leaves and calli of Nicotiana plumbaginifolia. Electron microscopic analysis only revealed linear molecules, although the same technique yielded a sizable fraction of circular mitochondrial DNA molecules in the fission yeast Schizosaccharomyces pombe. Most of the plant mitochondrial DNA molecules could be assigned to six size classes of 3.11 ± 0.19, 7.08 ± 0.53, 11.2 ± 0.29, 14.10 ± 0.23, 18.13 ± 0.39, and 23.17 ± 0.51 m length (mean ± 95% confidence intervals). These results are compared with those obtained for mitochondrial genomes of other higher plants.