• 동아시아식생활학회지
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• 제4권1호
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• pp.79-86
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• 1994

Food quality in food processing and storage were affected by the kinds of phenolics involved. To analyze phenolics of Chebulae Fructus by the way of GC-MSm methylation and trimethylsilyation(TMS) are necessary. The methods of methylation were dimethyl sulfate method and diazomethane method. so this study was undertaken to research the better methylation method before measuring GC-MS. But dimethyl sulfate method of methylation was not sufficient to analyze phenolics. So the phenolics of Chebulae Fructus were analyzed by the diazomethane methylation method and TMS with the pyridine, N-O-bis-trimethylsilyl-acetamide(BSTFA) and trimethylchlorosilane(TMCS). With the exception of pyrogallol and phloroglucinol in insoluble phenolics of Chebulae Fructus, the greater part of phenolics. analysis could be analyzed by GC-MS in company with diazomethane methylation method and TMS.

• Genomics & Informatics
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• 제9권3호
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• pp.136-137
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• 2011

Methylation of cytosine is a post-synthesis modification that does not affect the primary DNA sequence but greatly influences gene expression level and phenotypes of an organism. As high-throughput sequencing of bisulfite-treated DNA is the most efficient method to identify methylated sites, several tools to map sequencing reads on a reference are available. But tools to visualize and to interpret the methylation level of methylation sites are currently insufficient. Herein, we present a novel tool to visualize the methylation level of CpG sites.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3239-3242
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• 2013

An improved rapid method for determination of the fatty acid composition using modified methylation procedure was compared with the AOAC reference procedure based on the methylation of fatty acid with the addition of BF3 catalyst before and while heating. The new method is useful for research and routine quality control and has a number of advantages over the reference procedure which are more rapid, simple and also reliable. Applicability of the modified methylation method was confirmed with three vegetable oil samples (palm oil, coconut oil and olive oil). Based on the validation method results, we obtained that a quite linear calibration curve of fatty acids was performed with $R^2$ in range of 0.9972-0.9994. The sensitivity of gas chromatography instrument was able to analyze the fatty acids up to a few ppm, the precision and accuracy were good enough with the %RSD between 1.5%-19.5% and the recovery of linolenic acid was 99.1% in the range of 80.0%-113.3%.

• Journal of Korean Neurosurgical Society
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• 제59권1호
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• pp.26-36
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• 2016

Objective : This study investigated whether pyrosequencing can be used to determine the methylation status of the MGMT promoter as a clinical biomarker using relatively old archival tissue samples of glioblastoma. We also examined other prognostic factors for survival of glioblastoma patients. Methods : The available study set included formalin-fixed paraffin-embedded (FFPE) tissue from 104 patients at two institutes from 1997 to 2012, all of which were diagnosed histopathologically as glioblastoma. Clinicopathologic data were collected by review of medical records. For pyrosequencing analysis, the PyroMark Q96 CpG MGMT kit (Qiagen, Hilden, Germany) was used to detect the level of methylation at exon 1 positions 17-39 of the MGMT gene, which contains 5 CpGs. Results : Methylation of the MGMT promoter was detected in 43 (41.3%) of 104 samples. The average percentage methylation was $14.0{\pm}16.8%$ overall and $39.0{\pm}14.7%$ for methylated cases. There was no significant pattern of linear increase or decrease according to the age of the FFPE block (p=0.687). In multivariate analysis, age, performance status, extent of surgery, method of adjuvant therapy, and methylation status estimated by pyrosequencing were independently associated with overall survival. Additionally, patients with a high level of methylation survived longer than those with low methylation (p=0.016). Conclusion : In this study, the status and extent of methylation of the MGMT promoter analyzed by pyrosequencing were associated with overall survival in glioblastoma patients. Pyrosequencing is a quantitative method that overcomes the problems of MSP and a simple technique for accurate analysis of DNA sequences.

• BMB Reports
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• 제50권11호
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• pp.546-553
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• 2017

Aging is a natural and gradual process in human life. It is influenced by heredity, environment, lifestyle, and disease. DNA methylation varies with age, and the ability to predict the age of donor using DNA from evidence materials at a crime scene is of considerable value in forensic investigations. Recently, many studies have reported age prediction models based on DNA methylation from various tissues and body fluids. Those models seem to be very promising because of their high prediction accuracies. In this review, the changes of age-associated DNA methylation and the age prediction models for various tissues and body fluids were examined, and then the applicability of the DNA methylation-based age prediction method to the forensic investigations was discussed. This will improve the understandings about DNA methylation markers and their potential to be used as biomarkers in the forensic field, as well as the clinical field.

• 응용통계연구
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• 제24권4호
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• pp.609-622
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• 2011

The pattern of methylation draws significant attention from cancer researchers because it is believed that DNA methylation and gene expression have a causal relationship. As the interest in the role of methylation patterns in cancer studies (especially drug resistant cancers) increases, many studies have been done investigating the association between gene expression and methylation. However, a model-based approach is still in urgent need. We developed a finite mixture model in the Bayesian framework to find a possible relationship between gene expression and methylation. For inference, we employ Expectation-Maximization(EM) algorithm to deal with latent (unobserved) variable, producing estimates of parameters in the model. Then we validated our model through simulation study and then applied the method to real data: wild type and hydroxytamoxifen(OHT) resistant MCF7 breast cancer cell lines.

• 한국작물학회지
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• 제45권3호
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• pp.211-215
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• 2000

시료의 지방산 분석은 먼저 지방의 추출이 선행되어야 하는데 이때에는 시료량 및 시약이 많이 들고 또한 분석시간이 많이 소요되므로 지방 추출 및 지방산의 에스테르화를 한 단계에서 실시하는 One step extraction/methylation법(방법 1)에 따라 주요 유료작물의 지방산 조성을 살펴보았다 이 방법은 methanol-heptane-benzene-DMP-H$_2$SO$_4$ 혼합용매를 사용하여 지방 추출 및 지방산 에스테르화를 단일층에서 일어나게 한것으로 기존의 sodium methoxide를 촉매로 한 methanolysis 법에 의한 지방산 분석 결과와 유의적인 차이를 보이지 않았다. 또한 이 혼합시약으로 이미 추출된 지방을 대상으로 실험하였을 때에도(방법 2) 기존방법과 유의적인 차이가 없었다. 따라서 이 One step extraction/methylation법은 시료가 생체이든 추출된 지방이든 그 과정이 단순하고 시간과 노력이 훨씬 적게 소요되어 지방산 분석에 널리 이용될 수 있을 것이며, 특히 1회에 많은 시료를 처리하고자 할 때 더욱 분석효율이 높을 것으로 기대되었다

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.1917-1921
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• 2012

Background: Colorectal cancer is one of the leading causes of mortality worldwide. Genome wide analysis studies have identified sequence mutations causing loss-of-function that are associated with disease occurrence and severity. Epigenetic modifications, such DNA methylation, have also been implicated in many cancers but have yet to be examined in the East Asian population of colorectal cancer patients. Methods: Biopsies of tumors and matched non-cancerous tissue types were obtained and genomic DNA was isolated and subjected to the bisulphite conversion method for comparative DNA methylation analysis on the Illumina Infinium HumanMethylation27 BeadChip. Results: Totals of 258 and 74 genes were found to be hyper- and hypo-methylated as compared to the individual's matched control tissue. Interestingly, three genes that exhibited hypermethylation in their promoter regions, CMTM2, ECRG4, and SH3GL3, were shown to be significantly associated with colorectal cancer in previous studies. Using heatmap cluster analysis, eight hypermethylated and 10 hypomethylated genes were identified as significantly differentially methylated genes in the tumour tissues. Conclusions: Genome-wide methylation profiling facilitates rapid and simultaneous analysis of cancerous cells which may help to identify methylation markers with high sensitivity and specificity for diagnosis and prognosis. Our results show the promise of the microarray technology in identification of potential methylation biomarkers for colorectal cancers.

• Journal of Genetic Medicine
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• 제7권2호
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• pp.133-137
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• 2010

목 적: Beckwith-Wiedemann 증후군(BWS)은 11p15 부위의 메칠화 양상의 이상으로 인한 overgrowth malformation symdrome이다. 11p15 부위에는 두 가지 imprinting center, 즉BWSIC1 (IGF2, H19)와 BWSIC2 (LIT1,KvDMR)가 존재한다. 본 연구에서는 methylation-specific (MS) PCR RFLP 방법을 이용한 BWS의 유전적 진단을 보고하고자 한다. 대상 및 방법: 임상 소견을 바탕으로 12명의 BWS 환자가 포함되었다. 환자의 말초혈액으로부터 염색체 핵형을 조사하였다. 분리한 DNA에 bisulfite를 처리한 후, LIT1, H19, IGF2 DMR부위는 각각의 MS primer를 이용하여 증폭하였다. 적절한 제한효소를 이용하여 절단 여부를 PAGE로 확인함으로써 각각의 DMR 부위에 대한 메칠화 이상 여부를 확인하였다. 결 과: 12명의 환자는 모두 정상 핵형을 보였다. MS-PCR RFLP 상 총 7명(53.8%)의 환자가 이상 소견을 보였으며, 모두 BWSIC2 (LIT1)에 비정상적 메칠화를 보였고 모두 부계 유래의 비메칠화된 allele만이 발견되었다. 결 론: 본 연구를통해MS-PCR RFLP 검사로BWS 환자의 약 50-60% 정도에서 유전적 진단이 가능함을 알 수 있었으며, 이는 BWSIC2 부위의 메칠화 이상을 발견하는데 손쉽게 이용될 수 있을 것으로 판단된다. 그러나, BWSIC1 부위의 메칠화 이상은 발견이 어려우며, 이 부위의 이상을 발견하기 위해서는 메칠화를 정량적으로 분석할 수 있는 방법이 필요하다.

• BMB Reports
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• 제55권11호
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• pp.553-558
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• 2022

Hepatocellular carcinoma (HCC) is dangerous cancer that often evades early detection because it is asymptomatic and an effective detection method is lacking. For people with chronic liver inflammation who are at high risk of developing HCC, a sensitive detection method for HCC is needed. In a meta-analysis of The Cancer Genome Atlas pan-cancer methylation database, we identified a CpG island in the USP44 promoter that is methylated specifically in HCC. We developed methylation-sensitive high-resolution melting (MS-HRM) analysis to measure the methylation levels of the USP promoter in cell-free DNA isolated from patients. Our MS-HRM assay correctly identified 40% of patients with early-stage HCC, whereas the α-fetoprotein test, which is currently used to detect HCC, correctly identified only 25% of early-stage HCC patients. These results demonstrate that USP44 MS-HRM analysis is suitable for HCC surveillance.