• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.524-528
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• 2002

Green layer, Enteromorpha prolifera, is regarded as one of important materials for food processing in Korea. The acidic water-soluble polysaccharide (CPC-PS) isolated from the alga with hot water and cetylpyridium chloride was mainly constituted of rhamnose, xylose, uronic acid and sulfate. To determine the glycosyl-linkages and positions of sulfate by methylation, the CPC-PS was reduced and/or sulfates. A marked increase of glucose content in the reduced polysaccharide indicated that glucuronic acid was a major sugar in the polymer and sulfation was deduced to occur on O-3 of rhamnose and O-2 of xylose. According to the methylation analysis of the native, reduced, desulfated and reduced-desulfated polymers, CPC-PS mainly composed of 1,4- and 1,2,3-linked rhamnose 3-sulfate, 1,4-linked xylose 2-sulfate, 1,4-linked xylose and 1,4-linked glucuronic acid. Minor 1,4-linked rhamnose and 1,4,6-linked galactose residues were also detected.

• Archives of Pharmacal Research
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• v.21 no.6
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• pp.703-706
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• 1998

The anticomplementary activity of stilbenes from medicinal plants in Korea was investigated in vitro. 3,5-Dihydroxy-4'-methoxystilbene (3) was most potent with $IC_{50}$ value of $1.5{\times}10^{-4}M$ followed by rhapontigenin (4), oxyresverastrol (2), 2,3,4',5-tetrahydroxystilbene-2-O-beta-glucoside (9), rhaponticin (8), resverastrol (1), and piceid (7). The activity was found to be increased by a methylation on a hydroxy group of C-4' of 1, but decreased by further methylation on hydroxy groups of C-3 and C-5 and glucosylation on any hydroxy group of 1. Addition of hydroxy group on C-2' of 1 or C-3' of 3 was little affected on the anticomplementary activity but the activity was increased by O-glucosylation on C-2 of 1.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1090-1096
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• 2006

O-Methylation is a common modification reaction found in nature, and is mediated by an O-methyltransferase (OMT). OMTs have been mainly studied in plants, whereas only a few OMTs have been studied in microbes. When searching the Bacillus cereus genome, four putative small molecular OMTs were identified, among which BcOMT-1 was cloned and expressed in E. coli as a his-tag fusion protein. The whole cell expressing BcOMT-1 was used to methylate several flavonoids. Eriodictyol, luteolin, quercetin, and taxifolin, all of which contain 3' and 4' hydroxyl groups, served as methyl group acceptors for BcOMT-1, whereas naringenin, apigenin, 3,3'-dihydroxyflavone, and 3,4'-dihydroxyflavone did not function as substrates. Analysis of the reaction products using HPLC showed two different peaks, and NMR revealed that the methylation position was at the hydroxyl group of either carbon 3' or 4'. Therefore, this showed that BcOMT-1 used flavonoids containing ortho hydroxyl groups and transferred a methyl group to either of two hydroxyl groups.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.980-980
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• 2005

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6721-6726
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• 2013

Background: Changes in DNA methylation patterns are believed to be early events in hepatocarcinogenesis. A better understanding of methylation states and how they correlate with disease progression will aid in finding potential strategies for early detection of HCC. The aim of our study was to analyze the methylation frequency of tumor suppressor genes, P14, P15, and P73, and a mismatch repair gene (O6MGMT) in HCV related chronic liver disease and HCC to identify candidate epigenetic biomarkers for HCC prediction. Materials and Methods: 516 Egyptian patients with HCV-related liver disease were recruited from Kasr Alaini multidisciplinary HCC clinic from April 2010 to January 2012. Subjects were divided into 4 different clinically defined groups - HCC group (n=208), liver cirrhosis group (n=108), chronic hepatitis C group (n=100), and control group (n=100) - to analyze the methylation status of the target genes in patient plasma using EpiTect Methyl qPCR Array technology. Methylation was considered to be hypermethylated if >10% and/or intermediately methylated if >60%. Results: In our series, a significant difference in the hypermethylation status of all studied genes was noted within the different stages of chronic liver disease and ultimately HCC. Hypermethylation of the P14 gene was detected in 100/208 (48.1%), 52/108 (48.1%), 16/100 (16%) and 8/100 (8%) among HCC, liver cirrhosis, chronic hepatitis and control groups, respectively, with a statistically significant difference between the studied groups (p-value 0.008). We also detected P15 hypermethylation in 92/208 (44.2%), 36/108 (33.3%), 20/100 (20%) and 4/100 (4%), respectively (p-value 0.006). In addition, hypermethylation of P73 was detected in 136/208 (65.4%), 72/108 (66.7%), 32/100 (32%) and 4/100 (4%) (p-value <0.001). Also, we detected O6MGMT hypermethylation in 84/208 (40.4%), 60/108 (55.3%), 20/100 (20%) and 4/100 (4%), respectively (p value <0.001. Conclusions: The epigenetic changes observed in this study indicate that HCC tumors exhibit specific DNA methylation signatures with potential clinical applications in diagnosis and prognosis. In addition, methylation frequency could be used to monitor whether a patient with chronic hepatitis C is likely to progress to liver cirrhosis or even HCC. We can conclude that methylation processes are not just early events in hepatocarcinogenesis but accumulate with progression to cancer.

• Journal of Radiation Protection and Research
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• v.43 no.2
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• pp.66-74
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• 2018

Background: Tumor response to anticancer therapies can much be influenced by microenvironmental factors. In this study, we determined the effect of these microenvironmental factors on DNA methylation using A549 human lung adenocarcinoma cell line. Materials and Methods: We subjected A549 cells to various conditions mimicking tumor microenvironment including hypoxia, acidosis (sodium lactate), oxidative stress ($H_2O_2$), bystander effect (supernatant from doxorubicin (Dox)-treated or irradiated cells), and immune cell infiltration (supernatant from THP-1 or Jurkat T cells). Genomic DNA was isolated from these cells and analyzed for DNA methylation. Clonogenic cell survival, gene expression, and metabolism were analyzed in cells treated with some of these conditions. Results and Discussion: We found that DNA methylation level was significantly decreased in A549 cells treated with conditioned media from Dox-treated cells or Jurkat T cells, or sodium lactate, indicating an active transcription. To determine whether the decreased DNA methylation affects radiation sensitivity, we exposed cells to these conditions followed by 6 Gy irradiation and found that cell survival was significantly increased by sodium lactate while it was decreased by conditioned media from Dox-treated cells. We further observed that cells treated with conditioned media from Dox-treated cells exhibited significant changes in expression of genes including BAX and FAS (involved in apoptosis), NADPH dehydrogenase (mitochondria), EGFR (cellular survival) and RAD51 (DNA damage repair) while sodium lactate increased cellular metabolism rather than changing the gene expression. Conclusion: Our results suggest that various tumor microenvironmental factors can differentially influence DNA methylation and hence radiosensitivity and gene expression in A549 cancer cells.

• Journal of Korean Neurosurgical Society
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• v.59 no.1
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• pp.44-51
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• 2016

Objective : Malignant gliomas with neuronal marker expression (MGwNM) are rare and poorly characterized. Increasingly diverse types of MGwNM have been described and these reported cases underscore the dilemmas in the classification and diagnosis of those tumors. The aim of this study is to provide additional insights into MGwNM and present the clinicopathological features of 18 patients. Methods : We reviewed the medical records of 18 patients diagnosed as MGwNM at our institute between January 2006 and December 2012. Macroscopic total resection was performed in 11 patients (61%). We evaluated the methylation status of $O^6$-methylguanine-DNA methyltransferase (MGMT) and expression of isocitrate dehydrogenase 1 (IDH-1) in all cases, and deletions of 1p and 19q in available cases. Results : The estimated median overall survival was 21.2 months. The median progression-free survival was 6.3 months. Six patients (33%) had MGMT methylation but IDH1 mutation was found in only one patient (6%). Gene analysis for 1p19q performed in nine patients revealed no deletion in six, 19q deletion only in two, and 1p deletion only in one. The extent of resection was significantly correlated with progression free survival on both univariate analysis and multivariate analysis (p=0.002 and p=0.013, respectively). Conclusion : In this study, the overall survival of MGwNM was not superior to glioblastoma. The extent of resection has a significant prognostic impact on progression-free survival. Further studies of the prognostic factors related to chemo-radio therapy, similar to studies with glioblastoma, are mandatory to improve survival.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.528-528
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• 2005

• YAKHAK HOEJI
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• v.18 no.2
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• pp.161-164
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• 1974

m-Hydroxyaniline was reported to be converted to m-methoxyaniline with dimethylsulfate. However, while repeating the experiment with the same reaction condition, it was learned that the reaction product was not m-methoxyaniline but m-methoxy dimethylaniline. It was confirmed with nmr and ir spectrum and the comparison of bp and mp of the derivatives. Elemental analyses of the derivatives were also consistant with the fact N-dimethylation along with O-methylation occurred.

• BMB Reports
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• v.50 no.11
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• pp.537-538
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• 2017

Hypoxia affects various physiological and pathophyological processes. Hypoxia changes the expression of hypoxia-responsive genes through two main pathways. First, hypoxia activates transcription factors (TF) such as Hypoxia-inducible Factor (HIF). Second, hypoxia decreases the activity of Jumonji C domain-containing histone demethylases (JMJDs) that require $O_2$ and ${\alpha}$-Ketoglutarate (${\alpha}$-KG) as substrates. The JMJDs affect gene expression through their regulation of active or repressive histone methylations. Profiling of H3K4me3, H3K9me3, and H3K27me3 under both normoxia and hypoxia identified 75 TFs whose binding motifs were significantly enriched in the methylated regions of the genes. TFs showing similar binding strengths to their target genes might be under the 'metabolic control' which changes histone methylation and gene expression by instant changing catalytic activities of resident histone demethylases.