• Journal of Life Science
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• v.22 no.5
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• pp.657-664
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• 2012

The aim of this study is to screen a therapeutic agent with a cognitive function. The inhibitory effect of $Curcuma$ $longa$ hot water extract (CLWE) on the angiotension-converting enzyme and acetylcholinesterase derived from rabbit lungs and neural cells (PC12), as well as its antioxidant effect, was investigated in this study. Thus, for the first time, the direct scavenging effect of CLWE on DPPH radicals, superoxide anions, hydroxyl radicals, lipid peroxidation, reducing power, and the protective effect of DNA oxidation related to oxidative stress was evaluated in vitro. In addition, it was observed that CLWE especially exhibited a scavenging effect on reducing power and superoxide anions in this study. CLWE showed a protective effect on DNA oxidation produced by hydroxyl radicals. Furthermore, CLWE inhibited the activity of angiotensin-converting enzymes above 0.25%. Additionally, the extract inhibited oxidative stress and inducible nitric oxide in neuronal cells. Therefore, these results demonstrated that CLWE has antioxidant activity and neuronal cell protective effects, suggesting that it may have great potential as a natural source for human health.

• Molecules and Cells
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• v.19 no.1
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• pp.114-123
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• 2005

Nitropyrene, the predominant nitropolycyclic hydrocarbon found in diesel exhaust, is a mutagenic and tumorigenic environmental pollutant that requires metabolic activation via nitroreduction and ring oxidation. In order to determine the role of ring oxidation in the mutagenicity of 1-nitropyrene, its oxidative metabolites, 1-nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide, were synthesized and their mutation spectra were determined in the coding region of hprt gene of CHO cells by a PCR amplification of reverse-transcribed hprt mRNA, followed by a DNA sequence analysis. A comparison of the two metabolites for mutation frequencies showed that 1-nitropyrene 9,10-oxide was 2-times higher than 1-nitropyrene 4,5-oxide. The mutation spectrum for 1-nitropyrene 4,5-oxide was base substitutions (33/49), one base deletions (11/49) and exon deletions (5/49). In the case of 1-nitropyrene 9,10-oxide, base substitutions (27/50), one base deletions (15/50), and exon deletions (8/50) were observed. Base substitutions were distributed randomly throughout the hprt gene. The majority of the base substitutions in mutant from 1-nitropyrene 4,5-oxide treated cells were $A{\rightarrow}G$ transition (15/33) and $G{\rightarrow}A$ transition (8/33). The predominant base substitution, $A{\rightarrow}G$ transition (11/27) and $G{\rightarrow}A$ transition (8/27), were also observed in mutant from 1-nitropyrene 9,10-oxide treated cells. The mutation at the site of adenine and guanine was consistent with the previous results, where the sites of DNA adduct formed by these compounds were predominant at the sites of purines. A comparison of the mutational patterns between 1-nitropyrene 4,5-oxide and 1-nitropyrene 9,10-oxide showed that there were no significant differences in the overall mutational spectrum. These results indicate that each oxidative metabolite exhibits an equal contribution to the mutagenicity of 1-nitropyrene, and ring oxidation of 1-nitropyrene is an important metabolic pathway to the formation of significant lethal DNA lesions.

• Journal of Life Science
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• v.23 no.12
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• pp.1428-1435
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• 2013

The aim of this study is to investigate the melanogenic effect of Oenanthe javanica ethanolic extracts (OJE) containing quercetin and kaempferol in melanoma cells (B16F1). In order to determine whether OJE inhibits melanin synthesis at the cellular level, the melanoma cells were cultured in the presence of different concentrations of OJE. In the present study, the antioxidant effects of OJE on DPPH radical scavenging, power reduction, lipid peroxidation, and DNA oxidation were evaluated in a cell free system. Furthermore, the effect of OJE on the production of melanin was determined by dopaquinone (DOPA) assay and tyrosinase activity. In addition, the protein expression of tyrosinase, as well as antioxidant enzymes such as superoxide dismutase (SOD)-1, SOD-2 and glutathione reductase (GSH), were examined using Western blot analysis. In this study, it was observed that OJE exhibited an inhibitory effect on lipid peroxidation and blocked the DNA oxidation induced by the hydroxyl radical produced by Fenton's reagent. OJE increased melanin synthesis above 50 ${\mu}g/ml$ and tyrosinase activity was detected above 50 ${\mu}g/ml$. In Western blot analysis, OJE increased the expression levels of tyrosinase, SOD-1, SOD-2, and GSH in a dose-dependent manner. These findings indicate that OJE with antioxidant activity can regulate the tyrosinase activity and melanin production in melanocyte, suggesting that it could promote the development of black hair as well as protect skin from oxidative stress.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3695-3702
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• 2013

A nickel(II) complex $[Ni(H_2biim)_2(H_2O)_2](ClO_4)_2{\cdot}H_2O$ (1) of biimidazole ligand has been synthesized and characterized (Where $H_2biim$ = 2,2'-biimidazole). The single crystal X-ray diffraction of the complex shows a dimeric structure with six coordinated psudo-octahedral geometry. The cyclic voltammograms of complex exhibited one quasireversible reduction wave ($E_{pc}=-0.61V$) and an irreversible oxidation wave ($E_{pa}=1.28V$) in DMF solution. The interaction of the complex with Calf-Thymus DNA (CT-DNA) has been investigated by absorption and fluorescence spectroscopy. The complex is an avid DNA binder with a binding constant value of $1.03{\times}10^5M^{-1}$. The results suggest that the nickel(II) complex bind to CT-DNA via intercalative mode and can quench the fluorescence intensity of EB bind to CT-DNA with $K_{app}$ value of $3.2{\times}10^5M^{-1}$. The complex also shown efficient oxidative cleavage of supercoiled pBR322 DNA in the presence of hydrogen peroxide as oxidizing agent. The DNA cleavage by complex in presence of quenchers; viz. DMSO, KI, $NaN_3$ and EDTA reveals that hydroxyl radical or singlet oxygen mechanism is involved. The complex showed invitro antimicrobial activity against four bacteria and two fungi. The antimicrobial activity was nearer to that of standard drugs and greater than that of the free ligand.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.819-825
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• 2002

Methanol dehydrogenase (MDH) is a key enzyme in the process of methanol oxidation in methylotrophic bacteria. However, information on MDH genes from genus Methylobacillus is limited. In this study, a 6.5-kb HindIII DNA fragment of Methylobacillus sp. SK-5 chromosomal DNA was isolated from the genomic library of the strain by using a degenerate oligonucleotide probe that was designed based on JV-terminal amino acid sequence of the MDH $\alpha$ subunit purified from the strain. Molecular analysis of the fragment revealed four tightly clustered genes (mxaFJGI) involved in the methanol oxidation. The first and fourth genes were very similar to mxaF (77% identity for nucleotides an 78% identity for amino acids) and mxaF (67% Identity for nucleotides and 68% Identity for amino acids) genes, respectively, from Methylovorus sp. SSI. Genes mxaF and mxaI encode $\alpha$ and $\beta$ subunits of MDH, respectively. The two subunits were identified from purified MDH from Methylobacillus sp. SK-5. A dendrogram constructed by comparison of amino acid sequences of MDH u subunits suggests that MxaF from Methylobacillus sp. SK-5 belongs to a subfamily cluster of MDH u subunits from $\beta$-subgroup Proteobacteria. The subfamily cluster is separated from the other subfamily that consists of $\beta$- and $\gamma$-subgroup Proteobacteria. This study provided information on mn genes from a methylotrophic bacterium in $\beta$-subgroup Proteobacteria, which would aid to better develop a gene probe to detect one-carbon metabolizing bacteria.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.479-487
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• 2023

Copper is cost-effective and abundantly available as a biocidal coating agent for a wide range of material surfaces. Natural oxidation does not compromise the efficacy of copper, allowing it to maintain antimicrobial activity under prolonged exposure conditions. Furthermore, copper compounds exhibit a broad spectrum of antimicrobial activity against pathogenic yeast, both enveloped and non-enveloped types of viruses, as well as gram-negative and gram-positive bacteria. Contact killing of copper-coated surfaces causes the denaturation of proteins and damage to the cell membrane, leading to the release of essential components such as nucleotides and cytoplasm. Additionally, redox-active copper generates reactive oxygen species (ROS), which cause permanent cell damage through enzyme deactivation and DNA destruction. Owing to its robust stability, copper has been utilized in diverse forms, such as nanoparticles, ions, composites, and alloys, resulting in the creation of various coating methods. This mini-review describes representative coating processes involving copper ions and copper oxides on various material surfaces, highlighting the antibacterial and antiviral properties associated with different oxidation states of copper.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.1
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• pp.28-39
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• 2017

Persistent organic pollutants (POPs) can affect epigenetic mechanisms and obesity development. Polybrominated diphenyl ethers (PBDEs)-widely used to make flames-are one of the important POPs. Prenatal exposure to endocrine disrupting chemicals (EDCs), such as POPs, may affect global DNA methylation in long interspersed nuclear elements (LINE-1), increasing the risk of obesity later in life. Therefore, pregnant Sprague-Dawley (SD) rats were used to elucidate whether BDE-47 and BDE-209 transferred through placenta and breast milk cause epigenetic changes in LINE-1 and increase genetic susceptibility to obesity as obesogen during the developmental periods. Global DNA methylation in LINE-1 and gene expression related to obesity were measured in dams and offspring, using a methylation-sensitive high resolution melting analysis (MS-HRM) and direct bisulfite sequencing and quantitative real time polymerase chain reaction (qPCR), respectively. The results of MS-HRM showed global DNA hypomethylation patterns in LINE-1 of exposed offspring (2 of total 4) at PND 4, but bisulfite sequencing showed no difference in both the exposed and non-exposed groups. Gene expression in dams related to ${\beta}$-oxidation pathway and those related to adipokines showed different patterns between the two groups. On the contrary, gene expressions of offspring showed a similar pattern. Gene expressions related to ${\beta}$-oxidation pathway and obesity were significantly increased when compared with 'at birth', but not $PPAR-{\alpha}$. In conclusion, this study demonstrated the possibility that co-exposure to BDE-47 and BDE-209-via the placenta and breast milk-may affect epigenetic changes and modulate gene expression levels related to obesity.

• Journal of Microbiology
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• v.35 no.2
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• pp.141-148
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• 1997

Alcaligenes xylosoxydans strain SMN3 capable of utilizing biphenyl grew not only on phenol, and benzoate, but also on salicylate. Catabolisms of biphenyl and salicylate appear to be interrelated since benzoate is a common metabolic intermediate of these compounds. Enzyme levels in the excatechol 2. 3-dioxygenas which is meta-cleavage enzyme of catechol, but did not induce catechol 1, 2-dioxygenase. All the oxidative enzymes of biphenyl and 2, 3,-dihydroxybiphenyl (23DHBP) were induced when the cells were grown on biphenyl and salicylate, respectively. Biphenyl and salicylate could be a good inducer in the oxidation of biphenyl and 2, 3-dihydroxybiphenyl. The two enzymes for the degradation of biphenyl and salicylate were induced after growth on either biphenyl or salicylate, suggesting the presence of a common regulatory element. However, benzoate could not induce the enzymes responsible for the oxidation of these compounds. Biphenyl and salicylate were good inducers for indigo formation due to the activity of biphenyl dioxygenase. These results suggested that indole oxidation is a property of bacterial dioxygenase that form cis-dihydrodiols from aromatic hydrocarbon including biphenyl.

• Journal of Microbiology and Biotechnology
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• v.16 no.4
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• pp.511-518
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• 2006

A gene cluster for cyclohexanone oxidation was cloned from Rhodococcus sp. TK6, which is capable of growth on cyclohexanone as the sole carbon source. The 9,185-bp DNA sequence analysis revealed seven potential open reading frames (ORFs), designated as ssd-chnR-chnD-chnC-chnB-chnE-partial pcd. The chnBCDE genes encode enzymes for the four-step conversion of cyclohexanone to adipic acid, catalyzed by cyclohexanone monooxygenase (ChnB), $\varepsilon-caprolactone$ hydrolase (ChnC), 6-hydroxyhexanoate dehydrogenase (ChnD), and 6-oxohexanoate dehydrogenase (ChnE). Furthermore, the presence of a regulatory element in the downstream region of the chnD gene supports the notion that chnR is a putative regulatory gene. Among them, the activity of ChnB was confirmed and characterized, following their expression and purification in Escherichia coli harboring the modified chnB gene (chnB gene with 6 successive codons for His at the 3' terminus).

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.113-113
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• 1993

항바이러스 작용을 기대하여 6-azauridine의 2',3'-seco 유도체와 이들의 cyclic phosphate 유도체를 합성하였다. 6-azauridine으로부터 periodate oxidation에 의해 2',3'위치를 개열, 환원하여 얻은 triol의 3',5'위치를 acetonide 형으로 보호한 후 2'위치를 tosylation, azidation 하고 deprotection하여 2'-azido-2',3'-seco 유도체 (1)를 얻었다. 2',3'-diazido-2',3'-seco 유도체(2)는 6-azauridine의 2',3'-위치를 먼저 보호한후 5'위치를 benzoylation, 2',3'-deprotection, periodate oxidation 개열로 얻은 diol을 tosyl화 azido화 하고 deprotection하여 얻었다. 5'-azido-2',3'-seco 유도체(3)는 화합물 (2)의 합성시와 동일하게 먼저 2',3'-acetonide로 한후 5'-위치를 tosyl화, azido화 하고 deprotection, 2',3'-perodate 산화 개열등으로 얻었다. cyclic phosphate 유도체 (4)는 상기화합물 (2)를 4-NPPDC로 처리하여 3',5'-p-nitrophenylphosphoryltrioxy 유도체 (5)를 얻고 이것으로부터 3',5'-phosphoryltrioxy 유도체의 ammonium salt(4)를 얻었다. 이들 화합물의 DNA 및 RNA virus에 대한 antiviral activity는 현재 수행중이다.