• Molecular & Cellular Toxicology
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• v.5 no.1
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• pp.14-22
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• 2009

In vitro cytotoxicity of 23 alkyl phenols (APs) on human cervical cancer cell lines (HeLa) was determined using the lactate dehydrogenase (LDH) cytotoxicity assay. Two different sets of descriptors were used to construct the calibration model based on Genetic Algorithm-Multiple Linear Regression (GA-MLR) based on the experimental data. A statistically robust Structure-Activity Relationships (QSAR) model was achieved ($R^2$=95.05%, $Q^2_{LOO}$=91.23%, F=72.02 and SE= 0.046) using three Dragon descriptors based on Me (0D-Constitutional descriptor), BELp8 (2D-Burden eigenvalue descriptor) and HATS8p (3D-GETAWAY descriptor). However, external validation could not fully prove its validity of the selected QSAR in characterization of the cytotoxicity of APs towards HeLa cells. Nevertheless, the cytotoxicity profiles showed a finding that 4-n-octylphenol (4-NOP), 4-tert-octyl-phenol (4-TOP), 4-n-nonylphenol (4-NNP) had a more potent cytotoxic effect than other APs tested, inferring that increased length and molecular bulkiness of the substituent had important influence on the LDH cytotoxicity.

• Molecular & Cellular Toxicology
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• v.5 no.2
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• pp.141-146
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• 2009

Toll-like receptors (TLRs) induce innate immune responses by recognizing conserved microbial structural molecules. All TLR signaling pathways culminate in the activation of nuclear factor kappa-B (NF-$\kappa$B) leading to the induction of inflammatory gene products such as cyclooxygenase-2 (COX-2). Deregulated activation of TLRs can lead to the development of severe systemic inflammation. Divalent heavy metals, cadmium and mercury, have been used for thousands of years. While cadmium and mercury are clearly toxic to most mammalian organ systems, especially the immune system, their underlying toxic mechanism(s) remain unclear. Here, we report biochemical evidence that cadmium, but not mercury, inhibits NF-$\kappa$B activation and COX-2 expression induced by TLR2 or TLR4 agonists, while cadmium does not inhibit NF-$\kappa$B activation induced by the downstream signaling component of TLRs, MyD88. Thus, the target of cadmium to inhibit NF-$\kappa$B activation may be upstream of MyD88 including TLRs themselves, or events leading to TLR activation by agonists.

• Molecular & Cellular Toxicology
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• v.5 no.1
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• pp.88-92
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• 2009

The effect of Chlorella vulgaris (CV) on the urinary excretion of di-ortho PCB congeners (PCB-138, -153) was investigated. Sprague-Dawley rats (6-weeks-old, n=10 rats/group) were randomly divided into one control (0CV) or 2% CV (2CV) or 5% CV (5CV) or 10% CV (10CV) groups, respectively. Composition of normal and chlorella meal-based diet were made up of 30% casein, 15% cornstarch, 50% sucrose, 5% cellulose, 5% coconut oil, 3.5% mineral mixture, 1 % vitamin mixture. All rats had free access to water and diet for 4 weeks. A significant increase in both PCB 138 and 153 in urinary level was detected in CV fed groups, 540% and 167% for 2CV, 155% and 89% for 5CV, 114% and 144% for 10CV group, respectively, when compared with their controls. These findings suggest that CV may have potential to eliminate body burden levels of dioxin-like PCB compounds.

• Molecular & Cellular Toxicology
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• v.3 no.1
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• pp.11-18
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• 2007

Mechanisms of insecticide resistance found in insects may include three general categories. Modified behavioral mechanisms can let the insects avoid the exposure to toxic compounds. The second category is physiological mechanisms such as altered penetration, rapid excretion, lower rate transportation, or increased storage of insecticides by insects. The third category relies on biochemical mechanisms including the insensitivity of target sites to insecticides and enhanced detoxification rate by several detoxifying mechanisms. Insecticides metabolism usually results in the formation of more water-soluble and therefore more readily eliminated, and generally less toxic products to the host insects rather than the parent compounds. The representative detoxifying enzymes are general esterases and monooxygenases that catalyze the toxic compounds to be more water-soluble forms and then secondary metabolism is followed by conjugation reactions including those catalyzed by glutathione S-transferases (GSTs). However, a change in the resistant species is not easily determined and the levels of mRNAs do not necessarily predict the levels of the corresponding proteins in a cell. As genomics understands the expression of most of the genes in an organism after being stressed by toxic compounds, proteomics can determine the global protein changes in a cell. In this present review, it is suggested that the environmental proteomic application may be a good approach to understand the biochemical mechanisms of insecticide resistance in insects and to predict metabolomic changes leading to physiological changes of the resistant species.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.2
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• pp.179-185
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• 2000

The purpose of this study was to develop an osteogenic, biodegradable material using polymer and BMP. It was designed to have structural function and be moldable, for the reconstruction of load bearing areas and deformities of various configurations. Bone apatite was added to Poly(L-lactide)(PLLA) and made porous for osteoconductability and ease of BMP loading. The materials, with or without BMP purified from porcine bone matrix, were evaluated in cranial bone defect models in rats for biocompatibility and bone regeneration capability. The following results were obtained: The PLLA-BMP material with BMP added to the polymer showed 30% healing of cranial bone defects in rats during the 2 weeks to 3 months period of observation. The moldable PLLA agent without BMP also showed 25% bone healing capacity. Although new bone formation was incomplete in the critical size defect of rat cranium, it can be concluded that the unique moldability of those agents makes them useful for the reconstruction of various bone defects and maxillofacial deformities.

• Environmental Analysis Health and Toxicology
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• v.17 no.1
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• pp.73-80
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• 2002

Pyruvate dehydrogenase phosphatase (PDP)와 kinase는 당대사시 해당과정에서의 대사 산물인 pyruvate를 acetyl CoA로 만들어 구연산 회로로 진입시켜 주는 효소인 pyruvate dehydrogenase complex (PDC)의 활성을 조절하는 중요한 효소이다. PDP의 catalytic subunit는 PDC의 dihydrolipoamide acetyltransferase (E2), PDP regulatory subunit (PDPr), 그리고 칼슘 결합 도메인 등으로 구성되어 있는 것으로 추측되어지고 있다. 본 연구에서는 그 구조와 기능과의 상관관계를 알아보기 위해 PDPc를 E. coli JM101에서 발현시켜 순수 정제 후 단백분해 효소를 이용한 제한적 가수분해 방법을 이용해 그 구조와 기능과의 상관관계에 대해 연구하고자 하였다 정제된 PDPc는 trypsin, chymotrypsin, Arg-C 그리고 elastase를 이용하여 3$0^{\circ}C$ 그리고 pH 7.0에서 제한적으로 분해시켰으며 각 분해산물의 아미노 말단의 아미노산 배열을 분석하였다. 그 결과 PDPc는 trypsin, chymotrypsin, elastase에 의해 N-terminal의 50 kD과 C-terminal의 10 kD의 두개의 분해산물을 만들었으며, Arg-C에 의해 50kD의 분해산물은 약 35kD와 15kD으로 더 가수분해가 되었다. 이러한 결과로 볼 때 PDPc는 앞에서 추측한데로 세개의 주요한 기능적 도메인으로 이루어져 있음을 알 수 있었다 또한 C-terminal의 10kD은 PDPc의 활성에는 영향을 주지 않는 것으로 밝혀졌으나 다른 도메인의 기능은 더 연구가 되어져야 할 것으로 생각된다.

• Food Science of Animal Resources
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• v.25 no.2
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• pp.127-133
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• 2005

Aging effect of vacuum-packaged beef loins was investigated at $0\pm1^{\circ}C$ for 8 weeks. Hardness, chewiness, and shear force value of beef loins decreased steadily for the first 5 weeks of chilling period, but thereafter they did not changed significantly. Myofibrillar protein extractability, Mg-ATPase activity, and myofibrill fragmentation index of beef loins were increased for the first 6 weeks, and did not change for the rest period The Hunter's value in $L^{\ast},\;a^{\ast}\;and\;b^{\ast}$ of beef loin showed that no significant changes had occurred over the whole storage time. The palatability of beef loin was improved progressively for the first 5 weeks, but it became inferior thereafter. It can be concluded that the storage time to obtain optimum aging effect for the vacuum-packaged beef loin would be 5 weeks at $0^{\circ}C$ at the longest.

• Applied Biological Chemistry
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• v.42 no.2
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• pp.91-98
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• 1999

To select the desirable soybean cultivar for chonggugjang processing, the physicochemical characteristics of raw soybean materials and chonggugjang samples were investigated. Eight soybean varieties including Danyeobkong, Danbaegkong, Kwanankong, Pureunkong, Manlikong, Sinpaldalkong 2, Jinpeumkong and Hwankeumkong were used for experiment. On the basis of quality characteristics of raw materials, such as seed coat weight rate, hydration swelling, and the content of fructose, glucose and sucrose, and chonggugjang, such as hardness, ${\gamma}-glutamyltranspeptidase\;({\gamma}-GTP)$ activity, free amino acid content, and amino type nitrogen content, Sinpaldakong 2 and Danyeobkong were desirable soybean cultivars for high quality chonggugjang processing.

• Molecular & Cellular Toxicology
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• v.4 no.4
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• pp.285-292
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• 2008

Crocin is one of the major components of gardenia fruit and saffron which are widely used as natural food colorants and as traditional Chinese medicines. However, the genotoxicity data on crocin are not sufficient for safety evaluation. The purpose of this study was the examination of the genotoxicity on crocin from gardenia yellow in bacterial and mammalian cells, using various genotoxic battery testing assays and the influence of crocin on methyl methanesulfonate (MMS) and ${H_2}{O_2}$-induced DNA damage in vitro, using single cell gel electrophoresis (comet) assay. From results, no considerable mutagenicity and clastogenicity were seen in bacteria and mammalian cells treated with crocin, by Ames test, chromosomal aberration assay, ${tk}^{+/-}$ gene forward mutation assay and comet assay. And, post-treatment with crocin significantly suppressed ${H_2}{O_2}$-induced DNA damage in a dose-dependent manner. In conclusion, the findings of the present study and other previous observations indicate that crocin has no genotoxic potential. And it showed that crocin clearly repressed the genotoxic potency of ${H_2}{O_2}$. These results suggest that anti-oxidative effects of crocin may be involved in the protective effects of DNA damage.

• Environmental Analysis Health and Toxicology
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• v.18 no.4
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• pp.249-254
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• 2003

본 연구는 환경호르몬(endocrine disruptors)으로 분류되었으며, 에스트로젠 화합물의 특성을 지닌 4-Nonylphenol (NP)이 설치류 Pituitary 세포 중 성장호르몬을 분비하는 GH3 세포의 Nitric oxide(NO)을 증가시키는 작용기전을 규명코자 수행되었다 먼저 GH3세포에 NP처리 농도에 따른 NO의 생성을 측정한 결과 NP처리농도 의존적으로 증가시켰다. 이러한 NO의 증가가 genomic action인지를 확인하기 위해 GH3세포의 NO를 증가시키는 효소인 neuronal oxide synthase의 단백질량을 측정한 결과 GH3세포에서 NP에 의한 nNOS의 단백질의 변화는 없었다. 에스트로젠 화합물인 NP가 에스트로젠 리셉터 (ER)와의 관계를 조사하기 위해 ER억제제(ICI 168,780)클 처리한 경우 NP에 의해 증가한 NO가 감소하였다. 또한 유전자 전사억제제인 actinomycin D 및 단백질 발현 억제제인 cycloheximide을 처리한 경우는 NP에 의한 NO 증가억제효과가 없었다. 이러한 결과를 종합해 볼 때 GH3 세포에서 NP는 ER을 매개한 non-genomic action에 의해 NO를 증가키는 것으로 사료된다.