Search results for "MITOCHONDRIAL DNA"
showing 10 items of 259 documents
The basal levels of 8-oxoG and other oxidative modifications in intact mitochondrial DNA are low even in repair-deficient (Ogg1(-/-)/Csb(-/-)) mice.
2007
Abstract Mitochondrial DNA (mtDNA) is assumed to be highly prone to damage by reactive oxygen species (ROS) because of its location in close proximity to the mitochondrial electron transport chain. Accordingly, mitochondrial oxidative DNA damage has been hypothesized to be responsible for various neurological diseases, ageing and cancer. Since 7,8-dihydro-8-oxoguanine (8-oxoG), one of the most frequent oxidative base modifications, is removed from the mitochondrial genome by the glycosylase OGG1, the basal levels of this lesion are expected to be highly elevated in Ogg1−/− mice. To investigate this hypothesis, we have used a mtDNA relaxation assay in combination with various repair enzymes …
Aberrant methylation within RUNX3 CpG island associated with the nuclear and mitochondrial microsatellite instability in sporadic gastric cancers. Re…
2007
Background: Gastric cancer (GC) development is a multistep process, during which numerous alterations accumulate in nuclear and mitochondrial DNA. A deficiency of repair machinery brings about an accumulation of errors introduced within simple repetitive microsatellite sequences during replication of DNA. Aberrant methylation is related to microsatellite instability (MSI) by the silencing of the hMLH1 gene. The aim of this study is to investigate a possible relationship between the RUNX3 promoter methylation, nuclear microsatellite instability (nMSI) and mitochondrial microsatellite instability (mtMSI), in order to clarify its biological role in GC. Patients and methods: nMSI and mtMSI were…
Mitochondrial DNA effects on fitness in Drosophila subobscura
2011
We tested different fitness components on a series of conspecific mtDNA haplotypes, detected by RFLPs in Drosophila subobscura. Additionally, haplotype VIII, endemic to the Canary Islands, was tested upon its own native nuclear DNA background and upon that of the rest of mtDNAs tested herein. We found that both nuclear and mitochondrial DNA can have a significant effect upon their hosts' fitness, and that negative selection is one of the mechanisms that can intervene in this species' mtDNA haplotype pattern. We discuss the importance of this mechanism in relation to genetic drift, in the form of periodic population bottlenecks, and how the latter can enhance the former. We also detected a s…
Molecular oncology focus - is carcinogenesis a 'mitochondriopathy'?
2010
Abstract Mitochondria are sub-cellular organelles that produce adenosine triphosphate (ATP) through oxidative phosphorylation (OXPHOS). As suggested over 70 years ago by Otto Warburg and recently confirmed with molecular techniques, alterations in respiratory activity and in mitochondrial DNA (mtDNA) appear to be common features of malignant cells. Somatic mtDNA mutations have been reported in many types of cancer cells, and some reports document the prevalence of inherited mitochondrial DNA polymorphisms in cancer patients. Nevertheless, a careful reanalysis of methodological criteria and methodology applied in those reports has shown that numerous papers can't be used as relevant sources …
Molecular and ecological signs of mitochondrial adaptation: consequences for introgression?
2013
The evolution of the mitochondrial genome and its potential adaptive impact still generates vital debates. Even if mitochondria have a crucial functional role, as they are the main cellular energy suppliers, mitochondrial DNA (mtDNA) introgression is common in nature, introducing variation in populations upon which selection may act. Here we evaluated whether the evolution of mtDNA in a rodent species affected by mtDNA introgression is explained by neutral expectations alone. Variation in one mitochondrial and six nuclear markers in Myodes glareolus voles was examined, including populations that show mtDNA introgression from its close relative, Myodes rutilus. In addition, we modelled prote…
Mitochondrial biogenesis fails in secondary biliary cirrhosis in rats leading to mitochondrial DNA depletion and deletions
2011
Chronic cholestasis is characterizedby mitochondrial dysfunction, associated with loss of mitochondrialmembrane potential, decreased activities of respiratory chaincomplexes, and ATP production. Our aim was to determine themolecular mechanisms that link long-term cholestasis to mitochondrialdysfunction. We studied a model of chronic cholestasis inducedby bile duct ligation in rats. Key sensors and regulators of theenergetic state and mitochondrial biogenesis, mitochondrial DNA(mtDNA)-to-nuclear DNA (nDNA) ratio (mtDNA/nDNA) relativecopy number, mtDNA deletions, and indexes of apoptosis (BAX,BCL-2, and cleaved caspase 3) and cell proliferation (PCNA) wereevaluated. Our results show that long…
Mitochondrial DNA sequences are present inside nuclear DNA in rat tissues and increase with age
2009
Abstract Mitochondrial DNA (mtDNA) mutations increase with age. However, the number of cells with predominantly mutated mtDNA is small in old animals. Here a new hypothesis is proposed: mtDNA fragments may insert into nuclear DNA contributing to aging and related diseases by alterations in the nucleus. Real-time PCR quantification shows that sequences of cytochrome oxidase III and 16S rRNA from mtDNA are present in highly purified nuclei from liver and brain in young and old rats. The sequences of these insertions revealed that they contain single nucleotide polymorphisms identical to those present in mtDNA of the same animal. Interestingly, the amount of mitochondrial sequences in nuclear …
Tracing the genetic origin of Europe’s first farmers reveals insights into their social organization
2014
Farming was established in Central Europe by the Linearbandkeramik culture (LBK), a well-investigated archaeological horizon, which emerged in the Carpathian Basin, in today's Hungary. However, the genetic background of the LBK genesis has not been revealed yet. Here we present 9 Y chromosomal and 84 mitochondrial DNA profiles from Mesolithic, Neolithic Starčevo and LBK sites (7th/6th millennium BC) from the Carpathian Basin and south-eastern Europe. We detect genetic continuity of both maternal and paternal elements during the initial spread of agriculture, and confirm the substantial genetic impact of early farming south-eastern European and Carpathian Basin cultures on Central European p…
Assortative mating and fertility in two Drosophila subobscura strains with different mitochondrial DNA haplotypes.
2003
The mating pattern and female fertility on the two main mitochondrial DNA haplotypes (I and II) of Drosophila subobscura were studied, in an attempt to find possible differences between them in relation to sexual selection or isolation that could explain the populational dynamics and the co-existence of these two strains in nature. The mating pattern indicated an assortative mating in population cages, where couples of the same haplotype, mainly those of haplotype I, mated more often. However, the significations detected in laboratory conditions disappeared in wild populations, where random mating was the rule. The female fertility also showed differences in the laboratory compared to the w…
Mitochondrial alterations and tendency to apoptosis in peripheral blood cells from children with Down syndrome
2006
Different types of cells from subjects with Down syndrome (DS) have an increased susceptibility to cell death. We have studied apoptosis and mitochondrial (mt) membrane potential (DeltaPsi(m)) in peripheral blood mononuclear cells (PBMC) from DS children and age-matched healthy donors after in vitro treatment with apoptogenic molecules, along with mtDNA content. We found that PBMC from DS and healthy controls had a similar tendency to undergo apoptosis and a similar amount of mtDNA. However, in cells from DS subjects, mitochondria showed a higher loss of DeltaPsi(m), underlying the presence of an increasing susceptibility of these organelles to damaging agents.