• Journal of Life Science
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• v.9 no.1
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• pp.1-4
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• 1999

Large-scale deletions of mitochondrial DNA(mtDNA) have been documented in patients with mitochondrial myopathies and seem to be especially frequent in patients with Kearns-Sayre syndrome (KSS). About one third of all patients shows a 4,977 bp deletion, known as the "common deletion", that removes a segment of DNA that includes several genes encoding for respiratory chain subunits. In this disorder, the population of deleted mtDNA molecules coexists with population of normal, wild-type full length mtDNAs, a situation known as heteroplasmy. We have performed polymerase chain reaction (PCR) on paraffin-embedded muscle tissues from two korean KSS patients. The PCR analysis revealed the existence of two amplified fragments, the deleted fragments, the deleted fragment of 123 bp characteristic for common deletion and the wild-type fragment of 152 bp.of 152 bp.

• 보존과학연구
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• s.24
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• pp.153-167
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• 2003

We performed nuclear DNA typing and mitochondrial DNA sequencing analysis based on PCR from an ancient Korean remainsexcavated from Siheung in Korea. 7 bones were collected and partially STR(short tandem repeat) systems, Sex determination Amelogenin kit(Promega co, USA), were used in this study. Mitochondrial DNAs were also amplified and sequenced by ABI 310 DNA sequencer. We know that sample no. 2 and no. 3 were females and also sample no. 2 and no.7 possessed the same maternal inheritance by mitochondrial DNA sequencing results. Throughout this research, the mitochondrial DNA sequencing of human in the middle of Joseon Dynasty in Korea is obtained. In addition, this finding will be an important foundation for the future research.

• The Korean Journal of Zoology
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• v.36 no.1
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• pp.14-20
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• 1993

한국산 도룡농, Hvnobius leechii의 7개 집단에서 mitochondrial DNA(mtDNA)의 변이가 조사되었다. MtDNA의 크기에서의 차이는 관찰되지 않았으나 제한효소 인식 부위에서의 차이가 조사되었다. MtDNA의 절편 양상은 각 집단에서 동일하게 나타났다. 제한 효소로 처리하여 얻어진 절편의 비교에서 종내 변이는 염기 치환에 의하여 발생한 것임이 분석되어졌다. 특히 하동과 제주 집단은 몇개의 제한 효소 인식 위치에서 나머지 5개 집단과 뚜렷한 차이를 보였다. 염기치환율(p값)은 공통 절편 비율(p값)을 토대로 하여 얻어졌으며 그 값은 0.004에서 0.064의 범위 내의 값으로 측정되었다. 하동과 제주 집단을 제외한 5개 집단의 비교에서는 비교적 낮은 침의 염기 치환율을 보였으나 제주와 나머지 집단들과의 비교에서는 염기치환율이 높게 측정되었다. 염기 치환율과 관련지어 염기 분화 연대를 측정한 결과 도룡뇽 7개 집단은 3개의 group으로 나뉘어 졌으며 이들은 약 188만년전에 분화된 것으로 사료되어 진다.

• 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 $(3243A{\rightarrow}G,\;1555A{\rightarrow}4G,\;7445A{\rightarrow}G)$.

• The Korean Journal of Physiology and Pharmacology
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• v.23 no.6
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• pp.519-528
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• 2019

Mitochondrial dysfunction is closely associated with reactive oxygen species (ROS) generation and oxidative stress in cells. On the other hand, modulation of the cellular antioxidant defense system by changes in the mitochondrial DNA (mtDNA) content is largely unknown. To determine the relationship between the cellular mtDNA content and defense system against oxidative stress, this study examined a set of myoblasts containing a depleted or reverted mtDNA content. A change in the cellular mtDNA content modulated the expression of antioxidant enzymes in myoblasts. In particular, the expression and activity of glutathione peroxidase (GPx) and catalase were inversely correlated with the mtDNA content in myoblasts. The depletion of mtDNA decreased both the reduced glutathione (GSH) and oxidized glutathione (GSSG) slightly, whereas the cellular redox status, as assessed by the GSH/GSSG ratio, was similar to that of the control. Interestingly, the steady-state level of the intracellular ROS, which depends on the reciprocal actions between ROS generation and detoxification, was reduced significantly and the lethality induced by $H_2O_2$ was alleviated by mtDNA depletion in myoblasts. Therefore, these results suggest that the ROS homeostasis and antioxidant enzymes are modulated by the cellular mtDNA content and that the increased expression and activity of GPx and catalase through the depletion of mtDNA are closely associated with an alleviation of the oxidative stress in myoblasts.

• Parasites, Hosts and Diseases
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• v.41 no.1
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• pp.47-55
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• 2003

We compared patterns of intraspecific polymorphism of two markers with contrasting modes of evolution, nuclear ribosomal DNA (rDNA) and mitochondrial DNA (mtDNA), in the lung fluke, diploid and triploid Paragonimus westermani from three geographical regions of Korea. The genetic distances between three populations of Korean diploid and triploid P. westermani showed no significant difference in the nucleotide sequences of the mitochondrial cytochrome c oxidase subunit 1 (mtCOI) and ribosomaal second internal transcribed spacer (ITS2) genes. A highly resolved strict-consensus tree was obtained that illustrated phylogenetically useful information of the ITS2 and mtCOI sequences from diploid and triploid P. westermani.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8299-8305
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• 2016

Background: In Egypt, breast cancer is estimated to be the most common cancer among females. It is also a leading cause of cancer-related mortality. Use of circulating cell-free DNA (ccf-DNA) as non-invasive biomarkers is a promising tool for diagnosis and follow-up of breast cancer (BC) patients. Objective: To assess the role of circulating cell free DNA (nuclear and mitochondrial) in diagnosing BC. Materials and Methods: Multiplex real time PCR was used to detect the level of ccf nuclear and mitochondrial DNA in the peripheral blood of 50 breast cancer patients together with 30 patients with benign lesions and 20 healthy controls. Laboratory investigations, histopathological staging and receptor studies were carried out for the cancer group. Receiver operating characteristic curves were used to evaluate the performance of ccf-nDNA and mtDNA. Results: The levels of both nDNA and mtDNA in the cancer group were significantly higher in comparison to the benign and the healthy control group. There was a statistically significant association between nDNA and mtDNA levels and well established prognostic parameters; namely, histological grade, tumour stage, lymph node status andhormonal receptor status. Conclusions: Our data suggests that nuclear and mitochondrial ccf-DNA may be used as non-invasive biomarkers in BC.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1335-1340
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• 2006

It has been found that a number of diseases are associated with mutations in the mitochondrial DNA. Therapeutic gene delivery to mitochondria has been suggested as a clinical option for these diseases. In this study, we developed a gene carrier to mitochondria by the conjugation of mitochondrial leader peptide (LP) to polyethylenimine (PEI). Mitochondrial LP conjugated PEI (PEI-LP) was synthesized with low molecular weight PEI (2,000 Da, PEI2K). Gel retardation assay showed that PEI2K-LP formed complexes at a 1.0/1 weight ratio. In addition, PEI2K-LP protected DNA from the enzymatic degradation for at least 60 min, while naked DNA was completely degraded within 20 min. PEI2K-LP was compared with LP conjugated high molecular weight PEI (25,000 Da, PEI25K) in terms of toxicity and delivery efficiency. MTT assay showed that PEI2K-LP had much lower cytotoxicity than PEI25K-LP to 293 cells. In addition, cell-free DNA delivery assay showed that PEI2K-LP delivered more DNA to mitochondria at a 1.8/1 weight ratio than naked DNA or PEI. This result suggests that PEI2K-LP may be useful for the development of mitochondrial gene therapy system with lower cytotoxicity.

• Parasites, Hosts and Diseases
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• v.57 no.5
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• pp.481-487
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• 2019

Mitochondrial DNA sequence variability of Spirometra erinaceieuropaei in GenBank was observed by reinvestigation of mitochondrial cox1 and cytb sequences. The DNA sequences were analyzed in this study, comprising complete DNA sequences of cox1 (n=239) and cytb (n=213) genes. The 10 complete mitochondrial DNA sequences of Spirometra species were compared with those of Korea, China and Japan. The sequences were analyzed for nucleotide composition, conserved sites, variable sites, singleton sites and parsimony-informative sites. Phylogenetic analyses was done using neighbor joining, maximum parsimony, Bayesian inference and maximum-likelihood on cox1 and cytb sequences of Spirometra species. These polymorphic sites identified 148 (cox1) and 83 (cytb) haplotypes within 239 and 213 isolates from 3 Asian countries. Phylogenetic tree topologies were presented high-level confidence values for the 2 major branches of 2 Spirometra species containing S. erinaceieuropaei and S. decipiens, and S. decipiens sub-clades including all sequences registered as S. erinaceieuropaei in cox1 and cytb genes. These results indicated that mitochondrial haplotypes of S. erinaceieuropaei and S. decipiens were found in the 3 Asian countries.

• Korean Journal of Radiology
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• v.23 no.5
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• pp.566-567
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• 2022