• 한국산업보건학회지
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• 제19권1호
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• pp.73-79
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• 2009

This study was undertaken to investigate the effects of single and combined exposure of toluene (T) and xylene (X) on the cytochrome-450(CYP)-mediated metabolizing capacity, induction of CYP isozymes and the excretion of their metabolites in urine. Animal were adults male Sprague-Dawley (SD) rats and divided into 4 groups such as control, T (treated with 63.7 mg/body kg), X (treated with 65.9 mg/body kg) and TX(T=X). Organic solvents was administrated by intraperitoneal injection for 3 days. The contents of protein and CYP in liver microsomes of control group were $16.48{\pm}0.56 mg/m{\ell}$ and $0.744{\pm}0.025$ nmol/mg protein, respectively, and they contents were significantly lower than in derived from treated groups (p<0.01). The activities of PROD and ${\rho}NPH$ were significantly higher in single treated groups than in control and combined group (TX). When Western immunoblotting were carried out with two monoclonal antibodies (MAb 1-98-1 and MAb 2-66-3) which were specific against CYP2B1/2 and CYP2E1, respectively, a strong signal corresponding to CYP2B1/2 was observed in microsomes obtained from rats treated with X and TX. The color density against CYP2E1 was slightly increased in T and TX groups compared with C and X groups. The amounts of urinary hippuric acid in T single treated group was $3.29{\pm}1.97$ g/g creatinine and TX combined group was $2.91{\pm}1.76$ g/g creatinine, but was not significant. However, amount of urinary methy hippuric acid in X single treated group ($1.62{\pm}0.72$ g/g creatinine) was significantly higher than TX combined group ($0.93{\pm} 0.63$ g/g creatinine)(p<0.01). These results suggested that CYP2E1 isozyme might be responsible for the metabolism of T, and CYP2B1/2 isozyme is for X. And also, difference of metabolites level between single and combined group may be speculated that the intermediates of T and X interacted each other in the process of their metabolite formation reaction.

• Toxicological Research
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• 제18권1호
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• pp.13-22
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• 2002

In Korea, 2,320 tonnes of acetanilide were mostly wed as intermediates for synthesis in phar-maceuticals or additives in synthesizing hydrogen peroxide, varnishes, polymers and rubber. Only small amount of 120 kg were wed as a stabilizer for hydrogen peroxide solution for hair colouring agents in 1998. Readily available environmental or human exposure data do not exist in Korea at the present time. However, potential human exposures from drinking water, food, ambient water and in work places are expected to be negligible because this chemical is produced in the closed system in only one company in Korea and the processing factory is equipped with local ventilation and air filtering system. Acetanilide could be distributed mainly to water based on EQC model. This substance is readily biodegradable and its bioaccumulation is low. Acute toxicity of acetanilide is low since the L $D_{50}$ of oral exposure in rats is 1,959 mg/kg bw. The chemical is not irritating to skin, but slightly irritating to the eyes of rabbits. horn repeated dose toxicity, the adverse effects in rats were red pulp hyperplasia of spleen, bone marrow hyperplasia of femur and decreased hemoglobin, hematocrit and mean corpuscular hemoglobin concentration. The LOAEL for repeated dose toxicity in rats was 22 mg/kg/day for both sexes. Acetanilide is not considered to be genotoxic. In a reproductive/developmental toxicity study, no treatment-related changes in precoital time and rate of copulation, impregnation, pregnancy were shown in all treated groups. The NOAELs for reproduction and developmental toxicity (off-spring toxicity) are considered to be 200 mg/kg bw/day and 67 mg/kg bw/day, respectively. Ecotoxicity data has been generated in a limited number of aquatic species of algae (72 hr- $E_{b}$ $C_{50}$; 13.5 mg/l), daphnid (48hr-E $C_{50}$ > 100 mg/l) and fish (Oryzias latipes, 96hr-L $C_{50}$; 100 mg/l). Form the acute toxicity values, the predicted no effect concentration (PNEC) of 0.135 mg/1 was derived win an assessment factor of 100. On the basis of these data, acetanilide was suggested as currently of low priority for further post-SIDS work in OECD.in OECD.D.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 춘계학술대회 및 임시총회
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• pp.15-15
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• 2015

Aspergillus fumigatus is a major cause of invasive aspergillosis (IA), a significant health issue worldwide with high mortality rates up to 95%. Our lab is interested in how A. fumigatus adapts to low oxygen conditions 'hypoxia', which is one of the important host microenvironments. A. fumigatus SrbA is a basic helix-loop-helix (bHLH) transcriptional regulator and belongs to sterol regulatory element binding protein (SREBP) family members. Loss of SrbA completely blocks growth in hypoxia and results in avirulence in murine models of IA suggesting an essential role of SrbA in hypoxia adaptation and virulence in A. fumigatus. We conducted chromatin immunoprecipitation sequencing (ChIP-seq) with A. fumigatus wild type using a SrbA specific antibody, and 97 genes were revealed as SrbA direct targets. One of the 'SrbA regulons' (AFUB_099590) was a putative bHLH transcriptional regulator whose sequence contained a characteristic tyrosine substitution in the basic portion of the bHLH domain of SREBPs. Therefore, we designated AFUB_099590 SrbB. Further characterization of SrbB demonstrated that SrbB is important for radial growth, biomass production, and biosynthesis of heme intermediates in hypoxia and virulence in A. fumigatus. A series of quantitative real time PCR showed that transcription of several SrbA regulons is coordinately regulated by two SREBPs, SrbA and SrbB in hypoxia. This suggests that SrbA and SrbB have both dependent and independent functions in regulation of genes responsible for hypoxia adaptation in A. fumigatus. Together, our data provide new insights into complicated roles of SREBPs in adaptation of host environments and virulence in pathogenic fungi.

• 공업화학
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• 제26권3호
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• pp.311-318
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• 2015

내분비계교란물질로 알려진 비스페놀 A (bisphenol A, BPA) 수용액의 플라즈마 처리 및 분해 경로에 대해 조사하였다. 플라즈마화된 기체와 BPA 수용액을 효과적으로 접촉시키기 위하여 다공성 세라믹 관내에서 플라즈마를 생성시켜 세라믹 관의 세공을 통해 수중으로 고르게 분산시켰다. 기체의 유량, 인가 전압, 처리시간이 BPA 분해에 미치는 영향을 조사하였으며, 자외선 분광광도계, 이온 크로마토그래피, 기체크로마토그래피-질량분석기를 활용한 분석을 통해 반응 경로를 제시하였다. 기체의 유량이 너무 크거나 작으면 동일한 전력이 공급되더라도 처리효과가 떨어지며 적정한 기체 유량은 $1.0L\;min^{-1}$인 것으로 나타났다. 전압이 높을수록 많은 전력이 공급되므로 BPA를 제거하는 시간이 단축되나, 소모되는 에너지는 전압에 관계없이 유사하였다. 유량 $1.0L\;min^{-1}$과 전압 20 kV 조건에서 초기농도 $10L\;min^{-1}$ (부피 : 1 L)인 BPA가 30 min 이내에 모두 제거되었다. 오존이나 하이드록실 라디칼과 같은 활성성분들에 의해 BPA 구조가 파괴되어 생성되는 중간생성물들은 후속 산화반응을 통해 아세테이트, 포메이트, 옥살레이트와 같은 안정한 물질로 전환됨을 확인하였다.

• 환경위생공학
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• 제14권3호
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• pp.54-62
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• 1999

2,4-Dichlorophenol was known pollutants caused by the endocrine disruptor into the refractory substances of environment and this is difficult to be degradable by conventional methods. Therefore, a considerable interest has been devoted to developing new process where 2,4-Dichlorophenol can easily decomposed. In this study, the series of ultrasonic irradiation for removal of 2,4-Dichlorophenol has been selected as a model reaction in the batch reactor system in order to obtain the basic data investigate the influence of various experimental parameters such as concentration, pH, reaction temperature, acoustic intensity. The products obtained form the ultrasonic irradiation were analysed by GC/MS and HPLC. The formation of $H_2O_2$, a well-known the strong oxidant was found proportionally to increase with irradiation time. The intermediates of ultrasonic irradiation of 2,4-Dichlorophenol were identified as HCl, catechol, hydroquinone, o,p-benzoquinone, muconic acid, and maleic acid. The final products of this was $CO_2$ and $H_2O$. As the decomposition of 2,4-Dichlorophenol proceeds by the ultrasonic irradiation, the pH of 2,4-Dichlorophenol containing aqueous solution increases slowly, The decomposition of 2,4-Dichlorophenol was found to be occured fast in the basic medium. In general, the rate of reaction is proportional to the reaction temperature obeying the Arrhenius' law. However, in the ultrasonic irradiation, this suggests as the reaction temperature increase the decomposition rate of the reactant decreases. This result meant that the increase of reaction temperature due to the increase of vapor pressure of water accelerated the decrease of acoustic intensity which was can be proportional to the decomposition rae of these compounds. It was found that more than 80% of phenol solution was removed within hours in all reaction conditions. The reaction order in the degradation of the 2,4-Dichlorophenol compounds was verified as the Pseude-first order. From the fore-mentioned results, it can be concluded that the refractory organic compounds caused by endocrine disruptor as 2,4-dichlorophenol could be removed by the ultrasonic irradiation with radicals, such as $H{\;}{\cdot}{\;}and{\;}OH{\;}{\cdot}$ radical causing the high increase of pressure and temperature. Finally, it apeared that the technology using ultrasonic irradiation can be applied to the treatment of refractory substances caused by endocrine disruptor which are difficult to be decomposed by the conventional methods.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.89-91
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• 2000

Polynuclear aromatic hydrocarbon (PAH) compounds are highly carcinogenic chemicals and common groundwater contaminants that are observed to persist in soils. The adherence and slow release of PAHs in soil is an obstacle to remediation and complicates the assessment of cleanup standards and risks. Biological degradation of PAHs in soil has been an area of active research because biological treatment may be less costly than conventional pumping technologies or excavation and thermal treatment. Biological degradation also offers the advantage to transform PAHs into non-toxic products such as biomass and carbon dioxide. Ample evidence exists for aerobic biodegradation of PAHs and many bacteria capable of degrading PAHs have been isolated and characterized. However, the microbial degradation of PAHs in sediments is impaired due to the anaerobic conditions that result from the typically high oxygen demand of the organic material present in the soil, the low solubility of oxygen in water, and the slow mass transfer of oxygen from overlying water to the soil environment. For these reasons, anaerobic microbial degradation technologies could help alleviate sediment PAH contamination and offer significant advantages for cost-efficient in-situ treatment. But very little is known about the potential for anaerobic degradation of PAHs in field soils. The objectives of this research were to assess: (1) the potential for biodegradation of PAH in field aged soils under denitrification conditions, (2) to assess the potential for biodegradation of naphthalene in soil microcosms under denitrifying conditions, and (3) to assess for the existence of microorganisms in field sediments capable of degrading naphthalene via denitrification. Two kinds of soils were used in this research: Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS). Results presented in this seminar indicate possible degradation of PAHs in soil under denitrifying conditions. During the two months of anaerobic degradation, total PAH removal was modest probably due to both the low availability of the PAHs and competition with other more easily degradable sources of carbon in the sediments. For both Harbor Point sediment (HPS-2) and Milwaukee Harbor sediment (MHS), PAH reduction was confined to 3- and 4-ring PAHs. Comparing PAH reductions during two months of aerobic and anaerobic biotreatment of MHS, it was found that extent of PAHreduction for anaerobic treatment was compatible with that for aerobic treatment. Interestingly, removal of PAHs from sediment particle classes (by size and density) followed similar trends for aerobic and anaerobic treatment of MHS. The majority of the PAHs removed during biotreatment came from the clay/silt fraction. In an earlier study it was shown that PAHs associated with the clay/silt fraction in MHS were more available than PAHs associated with coal-derived fraction. Therefore, although total PAH reductions were small, the removal of PAHs from the more easily available sediment fraction (clay/silt) may result in a significant environmental benefit owing to a reduction in total PAH bioavailability. By using naphthalene as a model PAH compound, biodegradation of naphthalene under denitrifying condition was assessed in microcosms containing MHS. Naphthalene spiked into MHS was degraded below detection limit within 20 days with the accompanying reduction of nitrate. With repeated addition of naphthalene and nitrate, naphthalene degradation under nitrate reducing conditions was stable over one month. Nitrite, one of the intermediates of denitrification was detected during the incubation. Also the denitrification activity of the enrichment culture from MHS slurries was verified by monitoring the production of nitrogen gas in solid fluorescence denitrification medium. Microorganisms capable of degrading naphthalene via denitrification were isolated from this enrichment culture.

• 수산해양기술연구
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• 제18권2호
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• pp.101-108
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• 1982

유한요소법에 의한 고체내부 사각열원 주위 열전도특성은 실험에서 구한 결과와 거의 일치하였으며 열전도특성을 요약하면 다음과 같다. 1. 사각열원의 중심거리 이동에 따른 열전도에 미치는 중심방향의 영향은 열원 사이의 거리가 가까울수록 낮은 온도분포를 보이며 x=16cm 일 때 model 4에서 $\theta$=0.698 model 3에서는 $\theta$=0.401이다. 그리고 내부로 감에 따라 그 차는 감소한다. x=40cm에서 model 4은 $\theta$=0.907이고 model 6은 $\theta$=0.895이다. 2. 높이방향의 영향은 공기와 접하므로 대류현상이 일어나므로 열원의 크기를 벗어나는 구역은 model 1~3에서는 y=8~12cm model 4~6에서는 y=4~8cm이다. 그리고 두 곳의 온도의 차는 $\theta$≒0.009이다. 3. 열전도도의 변화에 따른 열전도의 영향은 그 값이 클수록 강하게 나타나며 model 2에 대해서 높이 방향의 전 경계에 대한 무차원온도의 변동은 k=7 일 때 $\theta$=0.079~0.054 k=0.3일 때 $\theta$=0.0036~0.0025의 값을 나타낸다

• BMB Reports
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• 제36권5호
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• pp.450-455
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• 2003

Antioxidant enzymes are scavenger reactive-oxygen intermediates and are involved in many cellular defense systems. We previously reported that a crude extract of Garnoderma lucidum, a medicinally potent mushroom, profoundly increased the catalase gene expression and enzyme activities in mouse livers (Park et al., J. Biochem. Mol. Biol. 34. 144-149, 2001). In this study, we elucidated the detailed mechanism whereby G. lucidum stimulates the catalase activity and expression. The major active fraction was isolated from G. lucidum and methyl linoleate was considered the most major component of the fraction. In order to determine whether methyl linoleate increases mRNA and protein synthesis of catalase, Northern and Western blot analyses were performed in vivo with methyl linoleate-treated mouse liver homogenate after feeding methyl linoleate to the mice. Northern and Western blot analyses of the crude liver homogenates in the mice that were administered methyl linoleate revealed that the expression catalase was significantly increased when compared to the untreated controls. In addition, the catalase protein levels and enzymatic activities increased in the mouse liver homogenates. These results suggest that methyl linoleate that is produced by G. lucidum stimulates the catalase expression at the transcription level.

• 한국발생생물학회지:발생과생식
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• 제11권2호
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• pp.59-66
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• 2007

배아줄기세포를 이용한 치료법 개발을 위해서는 배아줄기세포의 자가재생산 및 분화과정을 조절하는 분자적 기전을 이해하는 것이 매우 중요하다. 지질합성경로(Mevalonate pathway)에 작용하는 HMG-CoA 환원효소(Hydroxymethylglutaryl-coenzyme A reductase)의 억제제인 스타틴은 콜레스테롤 저하제로 잘 알려져 있으며, 콜레스테롤 이외에 단백질 isoprenylation의 기질로 작용하는 아이소프레노이드(Isoprenoids)(Farnesyl pyrophosphate(FPP), Geranylgeranyl pyrophosphate(GGPP))의 생성을 억제하는 효능을 가지고 있다. 스타틴에 의해 매개되는 표적단백질의 isoprenylation 억제는 다양한 세포내 신호전달과정에 영향을 미치게 되며, 결과적으로 세포기능을 조절하는데 핵심적인 역할을 하게 된다. 스타틴이 첨가된 배양배지에서 배양된 배아줄기세포는 자가재생산능이 억제되고 분화가 촉진되는데, 특히 지방/골세포 직계열로의 분화가 촉진된다. 배아줄기세포에서의 스타틴의 효과 및 작용기전에 대한 이해가 아직은 미비한 수준이나, 최근 우리 연구팀에서는 스타틴이 콜레스테롤 작용과는 무관하게 RhoA G-단백질의 세포내 분포 및 활성을 억제함으로써 배아 줄기세포의 자가재생산능을 억제하고 있음을 규명하였다. 스타틴 다면효과와 그 작용에 대한 이해는 배아줄기세포의 미분화 및 분화상태를 조절하는데 관여하는 분자적 조절기전을 이해하는데 중요한 모델이 될 수 있을 것으로 추정된다.

• 공업화학
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• 제7권5호
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• pp.888-901
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• 1996

V/Mo/P/Al/Ti-혼합 산화물 촉매상에서 고정층 적분식 반응기를 사용하여 공기로 1-펜텐과 시클로펜텐의 산화반응을 연구하였다. 고전환율에서 두 반응물들로부터 얻은 단일의 중요한 유기생성물은 무수말레인산이었고 동시에 소량의 무수프탈산을 얻었다. 한편, 1-펜텐 반응물로부터는 소량의 무수시트라콘산을 추가로 얻었다. 저전환율에서는 전체적으로 30개의 유기 산화 생성물들을 확인했으며, 그들중 일부는위에 언급된 3개의 무수물을 형성하기 위한 반응 중간체들 이었다. 전환율에 따른 유기 생성물들의 선택성을 근거로하여 무수말레인산, 무수프탈산 및 무수시트라콘산의 형성을 위한 반응경로를 제안했다. 한편, $310^{\circ}C$에서 공간속도의 감소에 따라 전환율과 무수말레인산의 선택성은 증가하였고, 무수말레인산의 최고선택성은 약 100%의 전환율에서 얻었다. $2{\cdot}10^4h^{-1}$의 일정한 공간속도에서 온도($300^{\circ}C{\sim}420^{\circ}C$)증가에 따라 전환율은 증가한 반면, 무수말레인산으로의 선택성은 시클로펜텐 산화반응의 경우 $370^{\circ}C$에서 약 39%의 최고값과 1-펜텐 산화반응의 경우 $400^{\circ}C$에서 약 30%의 최고값을 얻었다.