• Interdisciplinary Bio Central
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• v.3 no.4
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• pp.16.1-16.8
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• 2011

Defects in mitochondrial DNA (mtDNA) cause many human diseases and are critical factors that contribute to aging. The mechanisms of maternally-inherited mtDNA mutations are well studied. However, the role of acquired mutations during the aging process is still poorly understood. The most plausible mechanism is that increased reactive oxygen species (ROS) may affect the opening of mitochondrial voltage dependent anion channel (VDAC) and thus results in damage to mtDNA. This review focuses on recent trends in mtDNA research and the mutations that appear to be associated with increased ROS.

• Biomedical Science Letters
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• v.11 no.2
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• pp.227-235
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• 2005

It has been reported that endurance performance is influenced by various environmental and genetic factors. In view of an important role of human mitochondrial DNA (mtDNA) as a candidate for endurance performance, this study focused on the relationships between $VO_{2max}$ value as a measure of endurance performance or other associated phenotypes and four mtDNA restriction fragment length polymorphisms (RFLPs) (Bam HI, Hinc II1, Hinc II2 and Nci I) in the NADH dehydrogenase subunit 5 and one (Kpn I) in the D-loop region of mtDNA. MtDNA was purified from buffy coat in human peripheral blood, and PCR-RFLP analysis was performed to estimate the allele frequencies of each polymorphism in the mtDNA. There were no significant differences in allele distributions of all polymorphisms studied between male athletes and controls, respectively (P>0.05). However, the Kpn I polymorphism was significantly associated with diastolic blood pressure level in male athletes, respectively (P<0.05). Therefore, our results suggest that this polymorphism might be one of the factors modifying inter-individual difference in cardiovascular risk. Further studies using larger sample size will be required to generalize these results from the study described herein.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.11
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• pp.4493-4496
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• 2015

Alterations in mitochondrial DNA (mtDNA) have been studied in various cancers. However, the clinical value of mtDNA copy number (mtCN) alterations in gastric cancer (GC) is poorly understood. In the present study, we investigated whether alterations in mtCNs might be associated with clinicopathological parameters in GC cases. mtCN was measured in 109 patients with GC by real-time PCR. Then, correlations with clinicopathological characteristics were analyzed. mtCN was elevated in 64.2% of GC tissues compared with paired, adjacent, non-cancerous tissue. However, the observed alterations in mtCN were not associated with any clinicopathological characteristics, including age, gender, TN stage, Lauren classification, lymph node metastasis, and depth of invasion. Moreover, Kaplan-Meier survival curves revealed that mtCN was not significantly associated with the survival of GC patients. In this study, we demonstrated that mtCN was not a significant marker for predicting clinical characteristics or prognosis in GC.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.3
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• pp.203-206
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• 2003

Objectives: Controversial arguments exists on both the case for and against on the accumulation of mitochondrial DNA (mtDNA) deletion in association to tissue and age. The debate continues as to whether this mutation is a major contributor to the phenotypic expression of aging and common degenerative diseases or simply a clinical insignificant epiphenomenon. The objective of this study was to determine whether the accumulation of mtDNA deletion is correlated with age-related and tissue-specific variation. Materials and Methods: One hundred and fifty-seven tissues from blood, ovary, uterine muscle, and abdominal muscle were obtained from patients ranging in age from 31$\sim$60 years. After reviewing the clinical reports, patients with mitochondrial disorder were excluded from this study. The tissues were obtained at gynecological surgeries with the consent of the patient. Total DNA isolated from blood, ovary, uterine muscle, and abdominal muscle was amplified by two rounds of PCR using two pairs of primers corresponding to positions 8225-8247 (sense), 13551-13574 (antisense) for the area around deleted mtDNA and 8421-8440 (sense), 13520-13501 (antisense) for nested PCR product. A statistical analysis was performed by $x^2$-test. Results: About 0% of blood, 94.8% of ovary, 71.4% of uterine muscle, and 86.1% abdominal muscle harbored mtDNA deletion. When we examined the proportion of deleted mtDNA according to age deletion rate was 90% of ovary, 63.6% of uterine muscle, 77.7% of abdominal muscle in thirties and 100% of all tissue in fifties. Conclusion: The findings of this study suggest that the mtDNA deletion is varied in tissue-specific pattern and increases with aging.

• Journal of Nutrition and Health
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• v.48 no.5
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• pp.390-397
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• 2015

Purpose: In this study, we investigated the effects of chronic alcohol and excessive iron intake on mitochondrial DNA (mtDNA) damage and the progression of alcoholic liver injury in rats. Methods: Twenty-four Sprague-Dawley male rats were divided into four groups (Control, EtOH, Fe, and EtOH + Fe), and fed either control or ethanol (36% of total calories) liquid diet with or without 0.6% carbonyl iron for eight weeks. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, liver malondialdehyde concentrations were measured by colorimetric assays. Liver histopathology was examined by Hematoxylin-eosin staining of the fixed liver tissues. The integrity of the hepatic mtDNA and nuclear DNA was measured by long-range PCR. The gene expression levels of cytochrome c oxidase subunit 1 (Cox1) and NADH dehydrogenase subunit 4 (Nd4) were examined by real-time PCR. Results: Serum ALT and AST activities were significantly higher in the EtOH+Fe group, as compared to the Control group. Similarly, among four groups, liver histology showed the most severe lipid accumulation, inflammation, and necrosis in the EtOH + Fe group. PCR amplification of near-full-length (15.9 kb) mtDNA showed more than 50% loss of full-length product in the liver of the EtOH + Fe group, whereas amounts of PCR products of a nuclear DNA were unaffected. In addition, the changes in the mtDNA integrity showed correlation with reductions in the mRNA levels of mitochondrial gene Cox1 and Nd4. Conclusion: Our data suggested that the liver injury associated with excessive iron and alcohol intake involved mtDNA damage and corresponding mitochondrial dysfunction.

• Journal of Life Science
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• v.14 no.6 s.67
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• pp.913-919
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• 2004

Mitochondrial DNA mutations have been reported in recent years in association with sensorineural hering loss. The purpose of this study is to identify the association between the noise-induced sensorineural hearing loss and the A to G mutation at nucleotide 3243, 1555, 7445 of mitochondrial DNA. Study subjects were established by history and chart review, and audiological and clinical data were obtained. Blood was sampled from 214 normal controls, 102 noise-induced hearing loss, and 28 sensorineural hearing loss. The DNA of these individuals were extracted, and mitochondrial DNA fragments were analyzed by polymerase chain reaction. Subsequently, the coding sequence of mitochondrial DNA 3243, 1555, 7445 were sequenced, and compared to the normal sequence, and all sequence variations were analyzed by restriction enzymes. Mitochondrial DNA mutations $(3243A{\rightarrow}G,\;1555A{\rightarrow}4G,\;7445A{\rightarrow}G)$ were not detected by polymerase chain reactions in any patients with noise-induced hearing loss, sensorineural hearing loss, and normal controls. The DNA sequencing of PCR products did not revealed an A to G substitution at nucleotide 3243, 1555, 7445 of mitochondrial DNA. The noise-induced sensorineural hearing loss was not associated with mitochondrial DNA mutation $(3243A{\rightarrow}G,\;1555A{\rightarrow}4G,\;7445A{\rightarrow}G)$.

• Analytical Science and Technology
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• v.18 no.3
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• pp.257-262
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• 2005

Mitochondrial DNA (mt DNA) sequence analysis has been a useful tool for species identification of animals and human individuals. Two hypervariable regions (HV1 and HV2) in control region of mitochondrial genome were analyzed for human individual identification. In case of animal species identification, several genes on mt DNA such as cytochrome b (cytb), RNAs, cytochrome oxidases (CO) were used. In this study, co-amplification of HV1 and cytb was carried out in order to check the contamination of animal DNA and to verify the human DNA. The primer sets used in PCR were H15997/L16236 for HV1 and H14724/L15149 for cytb. PCR products for HV1 and cytb were 239 bp and 425 bp, respectively. The appearance of two bands on agarose gel implied the DNA came from human, however the single band of cytb gene represented the non-human animal DNA.

• Archives of Pharmacal Research
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• v.29 no.1
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• pp.88-95
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• 2006

Analysis of molecular nature of mitochondrial DNA (mtDNA) could be powerful marker for anthropological studies of modern populations. While population genetic studies on mtDNA have been reported for several ethnic groups, no such study has been documented for the Korean population. We surveyed mtDNA polymorphisms in the HVS I of noncoding D-loop region and its upstream region from 430 unrelated healthy Korean population by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and direct sequencing analysis. PCR product with 2,790 bp spanning the specific mtDNA region (mt13715-16504) was subjected to RFLP analysis using 6 restriction enzyme (Hinf I, Hae III, Alu I, Dde I, Mbo I, Rsa I). On the PAUP analysis of PCR-RFLP results, 38 mtDNA haplotypes (Hap 1-38) were detected in the Korean populations, which were classified into 11 haplogroups (Grp 1-11) of related haplotypes encompassing all 38 haplotypes. In comparison of sequencing data with Anderson's reference sequence, the transition type was more prevalent than the transversion type. Insertions or deletions were not found. In addition, three of the polymorphic sites (A16240C, A16351G, G16384A) in HVS-I region are determined newly. The polymorphic sites were distributed randomly in the region, though the frequency at each site was variable. Thus, this research might be required for the genealogical study of Orientals.

• Animal Systematics, Evolution and Diversity
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• v.36 no.2
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• pp.182-184
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• 2020

Isaacsicalanus paucisetus Fleminger, 1983, a monotypic species of the family Spinocalanidae Vervoort, 1951, was first reported from a hydrothermal vent field in the East Pacific Rise off the mouth of the Gulf of California. The mitochondrial cytochrome oxidase I(mtCOI) DNA barcodes are considered a useful tool to assist traditional taxonomy and species discrimination in calanoid copepods. However, the mtCOI DNA barcodes of I. paucisetus have not been reported due to the species rarity and the difficulty of sampling. In this study, we firstly determined the mtCOI DNA barcodes of the I. paucisetus newly collected from a hydrothermal vent in the North Fiji Basin of the southwestern Pacific. All mtCOI DNA barcodes of I. paucisetus were identical and intraspecies variations of spinocalanid species were 0.0-3.0%. Interspecies and intergeneric variations were 13.4-25.2% and 16.7-24.1%, respectively. The DNA barcodes of I. paucisetus obtained in the present study would be helpful for understanding taxonomic relationships of widespread spinocalanid species.

• Animal cells and systems
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• v.3 no.1
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• pp.79-87
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• 1999

Mitochondrial DNA (mtDNA) from 54 specimens of the blue mussel (Mytilus edulis) species complex sampled from the southern coast of Korea was assayed for polymorphism with a portion of the COIII gene (336 bp). Fifteen haplotypes were found. PAUP, one-step networks, and PHYLIP analyses revealed the presence of two clearly differentiated mitochondrial clades (termed clades B and E), separated by 3.6% of minimum sequence divergence. The distribution pattern of the species appears to be consistent with category II of the phylogeographic pattern sensu (Avise et al., 1987): the presence of two discontinuous and distinct mtDNA genotypes in the same geographic region. This unusual mitochondrial polymorphism was explained by the presence of the Mediterranean species, M. galloprovincialis, possessing mtDNA of both M. galloprovincialis and M. edulis.