Publications (35)84.63 Total impact
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Article: Homocysteine, folate and pregnancy outcomes.
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ABSTRACT: The purpose of this study is to evaluate the relationship between maternal and/or cord blood folate/homocysteine concentrations and adverse pregnancy outcomes. The study population included a random sample of singleton pregnant women in whom we measured total homocysteine and folic acid in maternal or cord blood at deliveries. A total of 227 pregnant women were enrolled. The concentration of folate in maternal blood tended to be significantly lower in pre-term birth than in full-term delivery group (median (95% CI), 14.4 (3.6-73) vs 25 (7.3-105.5) p < 0.01). The total homocysteine in maternal and cord blood was significantly higher in the pre-eclampsia than in the normotensive group (7.9 (1.7-28.2) vs 5.9 (1.8-14.6) μmol/ml, p < 0.05; and 5.8 (2.6-14.4) vs 4.2 (0.7-7.9) ng/ml, p < 0.05, respectively). Lower maternal serum folate concentration is associated with pre-term delivery and higher maternal plasma homocysteine concentration with pre-eclampsia.Journal of obstetrics and gynaecology: the journal of the Institute of Obstetrics and Gynaecology 08/2012; 32(6):520-4. · 0.43 Impact Factor -
Article: Improvement of biodegradability of industrial wastewaters by radiation treatment
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ABSTRACT: In order to evaluate the use of gamma-ray treatment as a pretreatment to conventional biological methods, the effects of gamma-irradiation on biodegradability (BOD5/COD) of textile and pulp wastewaters were investigated. For all wastewaters studied in this work, the efficiency of treatment based on TOC removal was insignificant even at an absorbed dose of 20 kGy. However, the change of biodegradability was noticeable and largely dependent on the chemical property of wastewaters and the absorbed dose of gamma-rays. For textile wastewaters, gamma-ray treatment increased the biodegradability of desizing effluent due to degradation of polymeric sizing agents such as polyvinyl alcohol. Interestingly, the weight-loss showed the highest value of 0.97 at a relatively low dose of 1 kGy. This may be caused by the degradation of less biodegradable ethylene glycol prior to terephthalic acid decomposition. For pulp wastewater, the gamma-ray treatment did not improve the biodegradability of cooking and bleaching of C/D effluents. However, the biodegradability of bleaching E1 and final effluents was abruptly increased up to 5 kGy then slowly decreased as the absorbed dose was increased. The initial increase of biodegradability may be induced by the decomposition of refractory organic compounds such as chlorophenols, which are known to be the main components of bleaching C/D and final effluents.Journal of Radioanalytical and Nuclear Chemistry 03/2006; 268(1):145-150. · 1.52 Impact Factor -
Article: Genotoxicity evaluation of electromagnetic fields generated by 835-MHz mobile phone frequency band.
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ABSTRACT: It is still unclear whether the exposure to electromagnetic fields (EMFs) generated by mobile phone radiation is directly linked to cancer. We examined the biological effects of an EMF at 835 MHz, the most widely used communication frequency band in Korean CDMA mobile phone networks, on bacterial reverse mutation (Ames assay) and DNA stability (in vitro DNA degradation). In the Ames assay, tester strains alone or combined with positive mutagen were applied in an artificial mobile phone frequency EMF generator with continuous waveform at a specific absorption rate (SAR) of 4 W/kg for 48 h. In the presence of the 835-MHz EMF radiation, incubation with positive mutagen 4-nitroquinoline-1-oxide and cumene hydroxide further increased the mutation rate in Escherichia coli WP2 and TA102, respectively, while the contrary results in Salmonella typhimurium TA98 and TA1535 treated with 4-nitroquinoline-1-oxide and sodium azide, respectively, were shown as antimutagenic. However, these mutagenic or co-mutagenic effects of 835-MHz radiation were not significantly repeated in other relevant strains with same mutation type. In the DNA degradation test, the exposure to 835-MHz EMF did not change the rate of degradation observed using plasmid pBluescript SK(+) as an indicator. Thus, we suggest that 835-MHz EMF under the conditions of our study neither affected the reverse mutation frequency nor accelerated DNA degradation in vitro.European Journal of Cancer Prevention 05/2005; 14(2):175-9. · 2.13 Impact Factor -
Article: Purification and characterization of arylsulfatase from Sphingomonas sp. AS6330
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ABSTRACT: Arylsulfatase was purified from Sphingomonas sp. AS6330 through ionic exchange, hydrophobic- and gel-chromatographies. The purity increased 12,800-fold with approximately 19.1% yield against cell homogenate. The enzyme was a monomeric protein with apparent molecular weight of 62kDa as determined by sodium dodecylsulfate-polyacrylamide gel electrophoresis, and 41kDa as determined by gel filtration. The enzyme had optimum reaction conditions for hydrolysis of sulfate ester bonds in agar and p-nitrophenyl sulfate (NPS) at pH7.0 and 45C, with a specific activity of 3.93 and 97.2U, respectively. The enzyme showed higher activity towards agar than other sulfated marine polysaccharides such as porphyran, fucoidan and carrageenan. The K m and V max of the enzyme for hydrolysis of NPS were 54.9M and 113mM/min, respectively. With reaction of 200g agar with 100U arylsulfatase for 8h at 45C, gel strength increased 2.44-fold, and 97.7% of the sulfate in the agar was hydrolyzed.Applied Microbiology and Biotechnology 04/2004; 63(5):553-559. · 3.42 Impact Factor -
Article: Peroxynitrite scavenging and cytoprotective activity of 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether from the marine alga Symphyocladia latiuscula.
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ABSTRACT: Peroxynitrite (ONOO(-)), formed from the reaction of superoxide (O(2)*(-)) and nitric oxide (*NO), is a cytotoxic species that can oxidize several cellular components such as proteins, lipids, and DNA. It has been implicated in diseases such as Alzheimer's disease, rheumatoid arthritis, cancer, and atherosclerosis. Due to the lack of endogenous enzymes responsible for ONOO(-) inactivation, developing a specific ONOO(-) scavenger is of considerable importance. The aim of this study was to evaluate the ability of marine natural products to scavenge ONOO(-) and to protect cells against ONOO(-). Methanolic extracts of 17 marine alga were tested for their ONOO(-) scavenging activity. Among them, Symphyocladia latiuscula showed the potent scavenging activity. CH(2)CH(2) fraction was partitioned with CH(2)CH(2) following n-hexanal extraction from the methanol extract of S. latiuscula. It was highly effective for ONOO(-) scavenging activity. Further analysis of the active fractionated extract identified 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (TDB) as a potent ONOO(-) scavenger. The data demonstrated that TDB led to decreased ONOO(-)-mediated nitration of tyrosine through electron donation. TDB showed significant inhibition on nitration of bovine serum albumin and low-density lipoprotein by ONOO(-) in a dose-dependent manner. It also provided cytoprotection from cell damage induced by ONOO(-). TDB can be developed as an effective peroxynitrite scavenger for the prevention of the involved diseases.Journal of Agricultural and Food Chemistry 09/2001; 49(8):3614-21. · 2.82 Impact Factor -
Article: Montipyridine, a new pyridinium alkaloid from the stony coral montipora species.
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ABSTRACT: A new pyridinium alkaloid, montipyridine (1), has been isolated from the stony coral Montipora sp. The structure was established from spectroscopic data.Journal of Natural Products 08/2001; 64(7):956-7. · 3.13 Impact Factor -
Article: ctr1, a gene involved in a signal transduction pathway of the gliding motility in the cyanobacterium Synechocystis sp. PCC 6803.
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ABSTRACT: We generated random Tn5 mutations in Synechocystis sp. PCC 6803 in search for genes involved in the signal transduction cascade for the cyanobacterial gliding motility. One of the non-gliding Tn5 mutants, S1-105, had an insertional inactivation in the slr1044 gene encoding a putative methyl-accepting chemotaxis protein. Interposon mutation on the slr1044 (named ctr1) in the bacterium also eliminated gliding motility. In the interposon mutant, the expression of pilA1 was 5-fold decreased compared with that of wild-type and thick pili, that are believed to be the motor for gliding, could not be observed by an electron microscope. Therefore, we suggest that the Ctr1 protein functions as a transducer that regulates the expression of pilA1, and thus is required for the biogenesis of thick pili.FEBS Letters 04/2001; 492(1-2):33-8. · 3.54 Impact Factor -
Article: New galactolipids from the marine bacillariophycean microalga Nitzschia sp.
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ABSTRACT: Two new galactopyranosyldiacylglycerols have been isolated from the marine bacillariophycean microalga Nitzschia sp. and their structures were determined as (2S)-3-O-beta-D-galactopyranosyl-1,2-di-O-(9Z-hexadecenoyl)glycerol (1) and (2S)-3-O-beta-D-galactopyranosyl-1-O-(5Z,8Z,11Z,14Z,17Z-eicosapentaenoyl)-2-O-(9Z-hexadecenoyl)glycerol (2) by physicochemical evidence.Natural Product Letters 02/2001; 15(5):299-306. -
Article: A new cyclic phenyllactamide from Salvia miltiorrhiza.
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ABSTRACT: From the rhizome of Salvia miltiorrhiza, a new cyclic phenyllactamide was isolated and characterized as 2,10,11-trihydroxy-8-methoxy-1,6,7,8-tetrahydro-2H-benzo[e]azecine-3,5-dione (1) from spectroscopic evidence. The new compound was found to be a scavenger of 1,1-diphenyl-2-picrylhydrazyl radical.Fitoterapia 02/2001; 72(1):30-4. · 1.85 Impact Factor -
Article: Proteome analysis of light-induced proteins in Synechocystis sp. PCC 6803: identification of proteins separated by 2D-PAGE using N-terminal sequencing and MALDI-TOF MS.
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ABSTRACT: The cyanobacterium Synechocystis sp. PCC 6803 is an ideal model organism for the proteome study of light-induced gene expression because the whole genomic sequence has been determined. The soluble proteins extracted from light- and dark-cultured cells were separated by two-dimensional polyacrylamide gel electrophoresis. Light-induced protein spots electroblotted on a polyvinyldiene difluoride membrane were analyzed by N-terminal Edman sequence determination and followed by CyanoBase. The tryptic digests of some proteins were also confirmed by matrix-assisted laser desorption ionization/time-of-flight (MALDI-TOF) and MS-Fit search. Interestingly, eight proteins were related to photosynthesis and respiration (RbcS/L, CbbA, Gap2, AtpB, CpcB, PsbO, and PsbU). Four proteins (SodB, DnaK, GroEL2, and Tig) were involved in cellular processes and the functions of another two proteins (rehydrin and membrane protein) were unknown. The proteome analysis by N-terminal Edman sequencing and MALDI-TOF enabled us to characterize one-shot protein profiles expressed under different physiological conditions.Molecules and Cells 01/2001; 10(6):705-11. · 2.18 Impact Factor -
Article: Comparative evaluation of antioxidant potential of alaternin (2-hydroxyemodin) and emodin.
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ABSTRACT: The antioxidant activities of alaternin (2-hydroxyemodin) and emodin were compared for their respective potentials to inhibit lipid peroxidation in the linoleic acid system by the thiocyanate method, to inhibit total reactive oxygen species generation in kidney homogenates using 2',7'-dichlorodihydrofluorescein diacetate, to inhibit peroxynitrite formation by the 3-morpholinosydnonimine system, which generates superoxide radical and nitrogen monooxide, and to scavenge authentic peroxynitrites. Both alaternin and emodin were found to inhibit the peroxidation of linoleic acid by the thiocyanate method in a dose-dependent manner. Whereas the former shows inhibitory activities in reactive oxygen- and nitogen-mediated reactions, the latter does not. These results indicate that alaternin is a potentially effective and versatile antioxidant and can be used to protect biological systems and functions against various oxidative stresses.Journal of Agricultural and Food Chemistry 01/2001; 48(12):6347-51. · 2.82 Impact Factor -
Article: A cyclohexanonyl bromophenol from the red alga Symphyocladia latiuscula.
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ABSTRACT: From an extract of the red alga Symphyocladia latiuscula, a bromophenol (1) was isolated and characterized as (2R)-2-(2,3, 6-tribromo-4,5-dihydroxybenzyl)-cyclohexanone based on the spectroscopic evidence. The bromophenol was found to be a scavenger of 1,1-diphenyl-2-picrylhydrazyl radical.Journal of Natural Products 01/2001; 63(12):1705-6. · 3.13 Impact Factor -
Article: New acetylenic compounds from the stony coral Montipora sp.
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ABSTRACT: Six new acetylenic compounds (1-6) with cytotoxic activities against human solid tumor cell lines (SK-OV-3, SK-MEL-2, XF498, and HCT15) have been isolated from the stony coral Montipora sp. Structures of the compounds 1-6 were elucidated based on analysis of the NMR and MS data.Journal of Natural Products 12/2000; 63(11):1511-4. · 3.13 Impact Factor -
Article: Isolation of luteolin 7-O-rutinoside and esculetin with potential antioxidant activity from the aerial parts of Artemisia montana.
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ABSTRACT: The antioxidant activity of Artemisia montana was determined by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and inhibitory activity against free radical generation of hepatocytes (AC2F). The methanol extract of A. montana showed strong radical scavenging activity at a concentration of 10.1 microg/ml, and thus fractionated by solvent extraction. Esculetin and luteolin 7-O-rutinoside (scolymoside) were isolated as the active principles from the EtOAc and Interphase fractions, respectively. The antioxidant activity of these compounds were comparable to that of L-ascorbic acid.Archives of Pharmacal Research 07/2000; 23(3):237-9. · 1.59 Impact Factor -
Article: Inhibition of NFkappaB by methyl chlorogenate from Eriobotrya japonica.
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ABSTRACT: Methylchlorogenic acid (MC) is one of the main components in the leaves of Eriobotrya japonica. We previously reported that MC is the most potent antioxidant among several components of Eriobotrya japonica, and its antioxidant activity is stronger than that of chlorogenic acid. Antioxidants are expected to inhibit redox-sensitive NFkappaB activation since NFkappaB is readily influenced by cellular oxidative state. Based on these findings, in vivo experiments with MC were conducted to determine its ability to downregulate the NFkappaB activation in mouse liver. Results clearly showed that MC is a potent suppressor of BHP-induced NFkappaB activation. We observed a significant reduction by MC on BHP-induced translocation of p65 subunit of NFkappaB. This may be due to formation of p50/p65 heterodimer, which is mainly inducible NFkappaB. MC slightly blocked the BHP-induced IkappaB alpha degradation. There is a possibility of IkappaB alpha resynthesis via activated NFkappaB during a 5 h waiting period following BHP injection. The present results suggest that MC may inhibit NFkappaB activation, exhibiting its ability to downregulate the NFkappaB-dependent gene expression. Thus, it can be expected that MC may have potential for therapeutic intervention on various NFkappaB-dependent pathological conditions such as inflammatory or possibly mutagenic processes.Molecules and Cells 07/2000; 10(3):241-6. · 2.18 Impact Factor -
Article: Identification of acylated glycoglycerolipids from a cyanobacterium, Synechocystis sp., by tandem mass spectrometry.
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ABSTRACT: Acylated glycoglycerolipids were identified in the total lipid extract from cyanobacterium Synechocystis sp. PCC 6803. These compounds have a palmitoyl group esterified to the hydroxyl group at the C-6 position of the terminal glycosyl moiety of digalactosyl monoacylglycerol and digalactosyl diacylglycerol. Their structural elucidation was accomplished by tandem mass spectrometry coupled with fast atom bombardment ionization. Acylated digalactosyl monoacylglycerol has a structure of 1-hydroxy-2-palmitoyl-3-O-[(6-O-palmitoyl)-alpha-D-galactopyranosyl -(1-->6)-beta-D-galactopyranosyl]-sn-glycerol. This compound has not been reported previously.Lipids 09/1999; 34(8):847-53. · 2.13 Impact Factor -
Article: Influence of 5,10-methylenetetrahydrofolate reductase gene polymorphism on plasma homocysteine concentration in patients with end-stage renal disease.
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ABSTRACT: The purpose of this study is to observe the influence of the methylenetetrahydrofolate reductase (MTHFR) gene (677C-->T substitution) on plasma homocysteine levels in end-stage renal disease (ESRD) patients who received a relatively large amount of folate (2 mg/d) and are undergoing hemodialysis. A cross-sectional study of plasma homocysteine, vitamin B(12), and folate was performed in patients with ESRD. The study population for the MTHFR gene study included 312 healthy subjects and 106 patients with ESRD undergoing hemodialysis. The C677T transition in the MTHFR gene was detected by HinF 1 restriction enzyme analysis and subsequent electrophoresis in a 3% agarose gel. The genotype of the MTHFR gene in 106 patients with ESRD was homozygous C677T mutation (VV) in 17 patients (16.1%) and heterozygous (AV) in 63 patients (58.4%); 26 patients (24.5%) did not carry this mutation (AA). The mean levels of homocysteine, vitamin B(12), and folate in the patients with ESRD were 23.3 +/- 14.0 mmol/L, 620.2 +/- 98.5 pmol/L, and 138.6 +/- 55.6 nmol/L, respectively. There was no significant difference in homocysteine levels among the three genotypes: 28.2 +/- 19.4 mmol/L for VV, 22.7 +/- 14.9 mmol/L for AV, and 23.4 +/- 11.1 mmol/L for AA genotype (P > 0.05). There was no difference in genotype distribution between the patient groups of less than 25th and greater than 75th percentiles, classified according to plasma homocysteine levels (P = 0.47). In conclusion, with high-dose folate supplementation, the hyperhomocysteinemia in patients with ESRD does not seem to be caused by the 677C-->T mutation in the MTHFR gene.American Journal of Kidney Diseases 09/1999; 34(2):259-63. · 5.43 Impact Factor -
Article: Photomovement of the gliding cyanobacterium Synechocystis sp. PCC 6803.
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ABSTRACT: Using a computerized videomicroscope motion analysis system, we investigated the photomovements of two Synechocystis sp. (PCC 6803 and ATCC 27184). Synechocystis sp. PCC 6803 displays a relatively slow gliding motion. The phototactic and photokinetic speeds of this cyanobacterium in liquid media were 5 microns/min and 15.8 microns/min, respectively, at 3 mumol/m2/s of stimulant white light. Synechocystis sp. PCC 6803 senses light direction rather than intensity for phototaxis. Synechocystis sp. ATCC 27184 showed a weak photokinesis but no phototaxis. Analysis of Synechocystis sp. ATCC 27184 suggests that the loss of phototaxis results from spontaneous mutation during several years of subculture. When directional irradiation was applied, the cell population of Synechocystis sp. PCC 6803 began to deviate from random movement and reached maximum orientation at 5 min after the onset of stimulant white light. Synechocystis sp. PCC 6803 showed high sensitivity to the stimulant white light of fluence rates as low as 0.002 mumol/m2/s. Neither 1,3-dichlorophenyldimethyl urea nor cyanide affected phototactic orientation, whereas cyanide inhibited gliding speed. This result suggests that the phototaxis of Synechocystis sp. PCC 6803 is independent of photosynthetic phosphorylation and that its gliding movement is primarily powered by oxidative phosphorylation. In the visible wavelength region, 560 nm, 660 nm and even 760 nm caused positive phototaxis. However, 360 nm light induced strikingly negative phototaxis. Therefore, at least two independent photoreceptors may exist to control phototaxis. The photoreceptor for positive phototaxis appears likely to be a phytochrome-like tetrapyrrole rather than chlorophyll a.Photochemistry and Photobiology 08/1999; 70(1):95-102. · 2.41 Impact Factor -
Article: Antioxidant flavonoids and chlorogenic acid from the leaves of Eriobotrya japonica.
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ABSTRACT: The antioxidant activity of Eriobotrya japonica was determined by measuring the radical scavenging effect on DPPH (1,1-diphenyl-2-picrylhydrazyl) radical and lipid peroxidation produced when mouse liver homogenate was exposed to the air at 37 degrees C, using 2-thiobarbituric acid (TBA). The methanol extract and its fractions of Eriobotrya japonica leaves showed strong antioxidant activity. The antioxidant activity of EtOAc and n-BuOH soluble fractions were stronger than the others, and were further purified by repeated silica gel, MCl gel CHP-20P, and Sephadex LH-20 column chromatography. Antioxidant chlorogenic acid, quercetin-3-sambubioside from n-BuOH fraction, and methyl chlorogenate, kaempferol- and quercetin-3-rhamnosides, together with the inactive ursolic acid and 2 alpha-hydroxyursolic acid from EtOAc fraction were isolated. Antioxidant flavonoids and chlorogenic acid also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method.Archives of Pharmacal Research 05/1999; 22(2):213-8. · 1.59 Impact Factor -
Article: Improved cycle sequencing of GC-rich DNA template.
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ABSTRACT: Even when DNA sequencing of purified DNA template failed under the optimal condition, it can be generally contributed to high GC content. GC-rich region of template causes a secondary structure to produce shorter readable sequence. To solve this problem, the sequencing reaction was modified by using dimethyl sulfoxide (DMSO). It was found that 5% (v/v) of DMSO in the reaction mixture recovers sequencing signal intensity with reduced frequency of ambiguous bases. When DMSO was added to sequencing reaction of DNA template with normal GC content, it did not show any adverse effect. Sequencing accuracy and unambiguous base frequency were significantly improved at concentration of 2% to 5% (v/v) DMSO in GC-rich DNA template. DMSO has been empirically introduced to enhance the efficiency of PCR in GC-rich templates. However, the underlying mechanism of improved cycle sequencing by DMSO is unknown. Thus, cycle sequencing reaction was remodified with other additives such as N-methyl imidazole, N-methyl2-pyrrolidone, N-methyl-2-pyridone and glycerol, possessing the similar chemical properties as DMSO. Most of methyl nitrogen ring-containing chemicals did not improve sequencing accuracy, whereas only glycerol mimicked the positive effect of DMSO by the same extent. In the present study, we suggest that the treatment of DMSO improve cycle sequencing by the alteration of structural conformation of GC-rich DNA template.Experimental and Molecular Medicine 04/1999; 31(1):20-4. · 2.48 Impact Factor
Top co-authors
Top Journals
Institutions
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1997–2004
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Pukyong National University
- Faculty of Food Science and Biotechnology
Pusan, Busan, South Korea -
Korea University
- Department of Biology
Seoul, Seoul, South Korea -
Kyungsung University
Pusan, Busan, South Korea
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1999–2001
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Korea Basic Science Institute KBSI
Seoul, Seoul, South Korea
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1991–2001
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Pusan National University
- Department of Food Science and Nutrition
Pusan, Busan, South Korea
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