• 한국미생물·생명공학회지
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• 제32권4호
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• pp.341-346
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• 2004

Escherichia coli의 생장을 저해하는 중금속(Cu, Cd, Cr, Hg, Zn) 영향을 정량적으로 조사하였고, 중금속 독성에 대한 적응과정에서의 독성변화를 노출시간대별로 평가하였다. 중금속에 의한 E. coli의 생장저해 작용은 중금속의 종류에 따라 다른 동향을 보였고, 생장을 완전 저해하는 중금속의 농도는 각각 Cu 3.5mM, Zn 2.5mM, Cd 1.5mM, Cr 1.2mM, Hg 0.12mM 이었다. $EC_{50}$을 기준으로 한 E. coli의 중금속에 대한 내성은 Cu > Zn > Cr > Cd > Hg 순이다. 노출 시간에 따른 $EC_{50}$의 변화를 plotting하여 그 기울기에 따라 피시험체의 독성물질에 대한 적응성 평가가 가능함을 보였다. 기울기 값이 작은 경우에는 피검사체가 독성물질에 대한 적응성이 약하고, 기울기 값이 크면 클수록 피시험체가 독성물질에 대한 적응성이 우수하다는 것을 의미한다. E. coli의 독성물질인 중금속에 대한 적응성은 Zn > Cd > Cu >> Cr > Hg 순 이었다.

• Toxicological Research
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• 제18권1호
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• pp.65-71
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• 2002

A benchmark dose (BMD) approach has been evaluated us a replacement for the traditional NOAEL methodology currently being wed to assess the noncancer effects of toxicants. The endocrine disrupt-ing effect of endosulfan which showed decrement of sperm count and testicular testosterone level in animals, was currently reported. The amount of endosulfan used as pesticide in the country has been continuously increased. The aim of this study was to suggest the permissible intake level (PIL), corresponding to Accept-able Daily Intake (ADI), based on endocrine disrupting effect wing BMD. Various animal data were collected by consideration of critical effect showing endocrine disruption and an animal data for reproductive toxicity was selected. The Power model from BMD software for induction of $BMD_10$ having meaning which is the dose at the 95% lower confidence limit on a 10% response was used due to that the form of selected dose-response animal data was continuous data. The $BMD_10$ was estimated to be 0.393 mg/kg/day based on reproductive toxicity showing decrement of sperm count. The permissible intake level (PIL) was calculated by dividing the $BMD_10$ by the uncertainty factors of 100 with consideration of from animal to human and human variability. The PIL as 0.004 mg/kg/day was compared with traditional ADI as 0.006 mg/kg/day based on the incidence of marked progressive glomerulonephrosis and blood vessel aneurysm in males.

• 한국환경보건학회지
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• 제30권4호
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• pp.347-351
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• 2004

A battery of sediment bioassays was performed for the sediments from the intertidal flat zone along the middle west coast of Korea to assess their potential toxicity. In the bioassays, three crustaceans, Daphnia magna, Nitocra spines, and Hyalella aztec a were exposed to $16\%$ sediments (wet weight) collected from 14 sites. Immobility($\%$) was checked as an endpoint after 24- and 48-h exposure of Daphnia magna and after 96-h exposure of Hyalella azteca and Nitocra spines. Among the three bioassays, the 48-h Daphnia bioassay showed the most distinct differential sensitivity in relation to sediment contamination, while the Nitocra and the Hyalella bioassays failed to show the differential sensitivity properly among the sites classified as polluted. Significantly different levels of immobility ($\%$) were obtained between the sites classified as chemical/nutrient polluted and the sites classified as non-polluted in the Daphnia bioassays, but not in the Nitocra bioassay and the Hyalella bioassay. Some differences of toxic response to the same sediments among bioassays were observed, suggesting that there may be a chemical specificity of response sensitivity to sediment toxicity, due to differences in bio-availability of sediment toxicants among test species.

• 한국환경과학회지
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• 제23권2호
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• pp.313-322
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• 2014

To investigate the effects of octylphenol and nonylphenol on the reproduction of the striped field mouse, the mice were subcutaneousely injected with 4-t-octylphenol 800 mg/kg (OP800), nonylphenol 900 mg/kg (NP900) or OP800 + NP900 (OPNP), respectively, in two times a week for 2 months. As the results, there were no differences between the control and the compound-treated groups in the body weight in both sexes, and the GSI (gonadosomatic index) and SVI (seminal vesicles index) in the adult males. But histological abnormalities of the reproductive organs in the mice seems to be related to the compound. This suggestion is supported by the facts that most mice treated with the compounds had only a small number of spermatozoa in the shrunken epididymal tubules. In addition, the shrunken reproductive organ in one mouse treated with the NP, suggests that the abnormalities in the wild striped field mice might be induced by the compound. Furthermore, it is indicated that the compounds must be toxicants to inhibit pregnancy, judging from the fact that all the mice treated with the compounds had failed to deliver.

• Molecular & Cellular Toxicology
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• 제1권3호
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• pp.157-163
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• 2005

Because of their widespread occurrence and substantial biological activity, halogenated aromatic hydrocarbons are one of the important classes of contaminants in the environment. We have performed comparative molecular field analysis (CoMFA) on structurally diverse ligands of Ah (dioxin) receptor to explore the physico-chemical requirements for binding. All CoMFA models have given $q^{2}$ value of more than 0.5 and $r^{2}$ value of more than 0.83. The predictive ability of the models was validated by an external test set, which gave satisfactory predictive $r^{2}$ values. Best predictions were obtained with CoMFA model of combined modified training set ($q^{2}=0.631,\;r^{2}=0.900$), giving predictive residual value = 0.002 log unit for the test compound. We have suggested a model comprises of four structurally different compounds, which offers a good predictability for various ligands. Our QSAR model is consistent with all previously established QSAR models with less structurally diverse ligands. The implications of the CoMFA/QSAR model presented herein are explored with respect to quantitative hazard identification of potential toxicants.

• Molecular & Cellular Toxicology
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• 제3권4호
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• pp.246-253
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• 2007

Doxorubicin and daunorubicin are excellent chemotherapeutic agents utilized for several types of cancer but the irreversible cardiac damage is the major limitation for its use. The biochemical mechanisms of doxorubicin- and daunorubicin- induced cardiotoxicity remain unclear. There are many reports on toxicity of doxorubicin and doxorubicin in cardiomyocytes, but effects in cardiovascular system by these drugs are almost not reported. In this study, we investigated gene expression profiles in human umbilical vein endothelial cells (HUVECs) to better understand the causes of doxorubicin and doxorubicininduced cardiovascular toxicity and to identify differentially expressed genes (DEGs). Through the clustering analysis of gene expression profiles, we identified 124 up-regulated common genes and 298 down-regulated common genes changed by more than 1.5-fold by all two cardiac toxicants. HUVECs responded to doxorubicin and doxorubicin damage by increasing levels of apoptosis, oxidative stress, EGF and lipid metabolism related genes. By clustering analysis, we identified some genes as potential markers on apoptosis effects of doxorubicin and doxorubicin. Six genes of these, BBC3, APLP1, FAS, TP53INP, BIRC5 and DAPK were the most significantly affected by doxorubicin and doxorubicin. Thus, this study suggests that these differentially expressed genes may play an important role in the cardiovascular toxic effects and have significant potential as novel biomarkers to doxorubicin and doxorubicin exposure.

• 한국물환경학회지
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• 제26권4호
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• pp.574-579
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• 2010

In this study the enzyme inhibition method using dehydrogenase which has been popularly used to estimate ecotoxicity was optimized. When three bacterial strains, Escherichia coli HB101, Enterobacter asburiae KCAD-4, and Aeromonas media KCAD-13, were compared, KCAD-4 was considered as the adequate strain to estimate toxicity because of its sensitivity and reproducibility. The optimal bacterial density was estimated as $5.4{\times}10^9CFU/mL$, at which the maximum sensitivity was observed. The phosphate buffer was suitable for the reaction solution. When the reaction times required for inhibition of enzyme activity by contact of toxicants and for reaction of damaged bacteria and substrate were tested, the optimal value was estimated as 20 min and 2 hrs, respectively. It is expected that the optimized conditions can be used to develop the standardized kits to estimate ecotoxicity of heavy metals in effluent from the industrial wastewater treatment facilities.

• International Journal of Industrial Entomology and Biomaterials
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• 제6권2호
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• pp.157-162
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• 2003

The glutathione S-transferase (GSTs) are enzymes responsible for the protection of cells from chemical toxicants and oxidative stress. We describe here the cDNA sequence and mRNA expression of a putative GST from the mole cricket, Gryllotalpa orientalis. The G. orientalis GST cDNA sequences comprised of 621 bp encoding 207 amino acid residues. The multiple sequence alignment of G. orientalis GST gene with other known insect GSTs showed several conserved residues that may be essential for the enzymatic activity of the protein. Phylogenetic analysis of the deduced amino acid sequences of G. orientalis GST gene with other insect GST sequences revealed that the G. orientalis GST gene belongs to class I GST, forming a strong monophyletic group (100% bootstrap value) exclusively for class I GSTs from a diverse insect species. Northern blot analysis confirmed midgut-specific expression at transcriptional level, evidencing the midgut as a site for GST synthesis.

• Biomolecules & Therapeutics
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• 제13권1호
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• pp.1-6
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• 2005

Lead and cadmium are potent environmental toxicants that affect populations living in Europe. Americas, and Asia. Identifying transporters for lead and cadmium could potentially 1 help us better understand possible risk factors. The iron transporter, divalent metal transporter 1 (DMT1), mediates intestinal transport of cadmium, and lead in yeast and fobroblasts overexpressing DMT1. In human intestinal cells knocking down expression of DMT1 attenuated uptake of cadmium and iron but not lead. A possible explanation is the expression of a second transporter for lead in intestine. In astrocytes, however, DMT1 appears to transport lead in an extracellular buffer at pH value. At neutral pH, transport was not mediated by DMT1 but rather by a transporter that is stimulated by bicarbonate and inhibited by 4,4'-diisothiocyanatodihydrostilbene-2,2'-disulfonic acid. The identity of this lead transporter will beverified by future study.

• Journal of Microbiology and Biotechnology
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• 제7권4호
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• pp.250-257
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• 1997

A new sensing system based on the immobilization of luminescent bacteria, photobacterium phosphoreum, was proposed for continuous real-time monitoring of pollutants. The response curves demonstrate that Photobacterium phosphoreum immobilized on the strontium alginate were very sensitive to seven reference chemicals used. The significant inhibitory concentrations for bioluminescence emission were 5 ppm for Pb$(NO_3)_2$), $NiCl_2$, $CdCl_2$, 50 ppm for $NaASO_2$, 0.1 ppm for $HgCl_2$, 0.5 ppm for pentachlorophenol and less than 5 ppm for SDS, respectively. The alginate mixed-cells (AMC) retained their luminescence during experimental period (29 days) under storage condition of $-80^{\circ}C$. The variables affecting performance of continuous flow through monitoring (CFTM) was optimized in order to ensure stability and efficiency. The flow through cell with strontium-alginate immobilized luminescent bacteria was tested with salicylate and 4-nitrophenol. A rapid response of luminescence was recorded by time drive mode in bioluminescence spectrometer after exposure to both toxicants.