• 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.

• Archives of Pharmacal Research
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• v.29 no.3
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• pp.235-240
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• 2006

The oral administration of extracts of young radishes cultivated with sulfur after intravenous tumor cell injection achieved a marked reduction of pulmonary colonization in mice. Treatment of the mice with extracts of young radish cultivated with sulfur did not show any increase in the number of CD8+ or NK T cells in the spleen, indicating no influence on host immunity. Sulforaphane, which could be a candidate for an active compound from young radishes cultivated with sulfur, inhibited cell growth of B16-F10 melanoma cells. In addition, extracts of the young radish cultivated with sulfur-fed group showed enhanced quinine reductase (QR) activities in the liver and lung and a slight increase of glutathione S-transferase (GST) activity in the liver. These results suggested that the administration of extracts of young radishes cultivated with sulfur suppressed pulmonary tumorigenesis, possibly due to increased activity of detoxification enzymes in the liver and lung, and partly due to cell cytotoxicity.

• Biomolecules & Therapeutics
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• v.1 no.1
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• pp.71-76
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• 1993

It has been reported that d-limonene inhibits chemical-induced rat mammary cancer by the mechanism of increases in detoxification enzymes such as glutathione S-transferases and that cineole fails to exhibit significant suppressive effect on chemical-induced carcinogenesis. The present study was designed to compare the effects of d-limonene and cineole on the benzo(a)pyrene (BP)-induced mutagenicity, BP metabolism and lipid peroxidation. Modified Ames assay was employed to evaluate the inhibitory effect of d-limonene and cineole on the BP-induced mutagenicity. The number of revertant-bearing wells was decreased by 44~77% in the presence of both BP and d-limonene compared with that of BP alone whereas cineole decreased the number of revertant-bearing wells by 28~45% at the concentrations between $2{\mu}m$m.TEX> and 2 mM. d-Limonene suppressed BP metabolism by 16, 54 and 67% at 1, 10 and 100 mM, respectively while cineole inhibited the metabolism by 16, 26 and 55% at the same concentrations. The $EC_{50}$ values for d-limonene and cineole in inhibiting lipid peroxidation were 2.0 mM and 16 mM respectively, as assayed by thiobarbituric acid method. The present study showed that d-limonene and cineole have common antimutagenic effects although d-limonone appeared to be more effective than cineole in suppressing mutation and lipid peroxidation. The results suggest that the antimutagenic effects of d-limonene and cineole may be associated with alternation in enzyme activities and with inhibition of lipid peroxidation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.4
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• pp.298-302
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• 2019

Acidic soil significantly reduces crop productivity mainly due to aluminum (Al) toxicity. Alfalfa (Medicago sativa L.) roots were exposed to aluminum stress (Al₃⁺) in calcium chloride (CaCl₂) solution (pH4.5) and root growth, physiological and antioxidant enzyme responses were investigated. The root growth (length) was significantly inhibited after 48 h of aluminum stress imposition. Histochemical staining with hematoxylin indicated significant accumulation of aluminum in Al stress-treated root tissues. Histochemical assay were also performed to detect superoxide anion, hydrogen peroxide and lipid peroxidation, which were found to be more in root tissues treated with higher aluminum concentrations. The enzymatic activity of CAT, POD and GR in root tissues was slightly increased after Al stress treatment. The result suggests that Al stress alters root growth in alfalfa and induces reactive oxygen species (ROS) production, and demonstrates that antioxidant enzymes involved in detoxification of Al-mediated oxidative stress.

• Korean Journal of Pharmacognosy
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• v.28 no.2
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• pp.88-92
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• 1997

The full NMR assignment of hispidulin 7-0-neohesperidoside (1) isolated from Cirsium japonicum var. ussuriense was made with the aid of 2D correlation NMR techniques such as HMQC and HMBC. To investigate detoxification of bromobenzene-induced hepatic lipid peroxidation by compound 1, hepatic lipid peroxide level and the activities of enzymes responsible for production and removal of epoxide were studied. The level of lipid peroxide elevated by bromobenzene was significantly reduced by compound 1. This compound administered daily over one week before intoxication with bromobenzene did not affect the activities of aminopyrine N-demethylase, aniline hydroxylase, glutathione S-transferase. Epoxide hydrolase activity was decreased significantly by bromobenzene, which was restored to the control level by pretreatment of persicarin. The results suggest that the bromobenzene-induced hepatic lipid peroxidation by compound 1 is reduced by enhancing the activity of epoxide hydrolase, an enzyme removing bromobenzene epoxide.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.1
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• pp.126-130
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• 2008

Water extract from Prunella vulgaris L. (PVW) was tested for colon cancer chemopreventive activity by measuring the activities of cytochrome P450 1A1, phase Ⅱ detoxification enzyme [quinone reductase (QR) and glutathione S-transferase (GST)] and ornithine decarboxylase (ODC) and glutathione (GSH) levels in cultured human colorectal adenocarcinoma HT-29 cells. PVW significantly inhibited 7,12-dimethylbenz[a]anthracene (DMBA)-induced cytochrome P450 1A1 activity at 10 and 50 ${\mu}g/ml$. PVW induced QR activity in a dose-dependent manner over a concentration range of $1{\sim}50\;{\mu}g/ml$. GST activity was also induced with the treatment of PVW in HT-29 cells. In addition GSH levels were increased with PVW. PVW inhibited ODC activity, a key enzyme of polyamine biosynthesis, which is enhanced in tumor promotion. These results suggest that Prunella vulgaris L. has colon cancer chemopreventive activity by inhibiting cytochrome P450 1A1 and ODC activities and by increasing phase Ⅱ enzyme activity and GSH levels.

• Journal of Embryo Transfer
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• v.25 no.4
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• pp.273-279
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• 2010

Follicular cystic follicles (FCFs) show delayed regression with persistent follicle growth. However, the mechanism by which follicles are persistently grown remains unclear. Glutathione S-transferases (GSTs) are drug-metabolizing and detoxification enzymes that are involved in the intracellular transport and metabolism of steroid hormones. In this study, a proteomic analysis was performed to identify whether GST expression is changed in bovine FCFs and to predict the interactions between GST and other proteins. Normal follicles and FCFs were classified based on their sizes (5 to 10 mm and 25 mm). In bovine follicles, GST mu 1 (GSTM1) was detected as a differentially expressed protein (DEP) and significantly up-regulated in FCFs compared to normal follicles (p<0.05). Consistent with the proteomic results, semi-quantitative PCR data and western blot analysis revealed an up-regulation of GSTM1 in FCFs. Expression levels of aromatase and dehydrogenase proteins were changed in FCFs. These results show that the up-regulation of GSTM1 that is observed in bovine FCFs is likely to be responsible for the persistent follicle growth in FCFs as the activity of aromatase and the dehydrogenases.

• BMB Reports
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• v.37 no.2
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• pp.139-143
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• 2004

The antioxidant responsive element (ARE) is a cis-acting regulatory element of genes encoding phase II detoxification enzymes and antioxidant proteins, such as NAD(P)H: quinone oxidoreductase 1, glutathione S-transferases, and glutamate-cysteine ligase. Interestingly, it has been reported that Nrf2 (NF-E2-related factor 2) regulates a wide array of ARE-driven genes in various cell types. Nrf2 is a basic leucine zipper transcription factor, which was originally identified as a binding protein of locus control region of ss-globin gene. The DNA binding sequence of Nrf2 and ARE sequence are very similar, and many studies demonstrated that Nrf2 binds to the ARE sites leading to up-regulation of downstream genes. The function of Nrf2 and its downstream target genes suggests that the Nrf2-ARE pathway is important in the cellular antioxidant defense system. In support of this, many studies showed a critical role of Nrf2 in cellular protection and anti-carcinogenicity, implying that the Nrf2-ARE pathway may serve as a therapeutic target for neurodegenerative diseases and cancers, in which oxidative stress is closely implicated.

• The Plant Pathology Journal
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• v.35 no.2
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• pp.91-99
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• 2019

Mitogen-activated protein kinase (MAPK) cascades in fungi are ubiquitously conserved signaling pathways that regulate stress responses, vegetative growth, pathogenicity, and many other developmental processes. Previously, we reported that the AbSte7 gene, which encodes a mitogen-activated protein kinase kinase (MAPKK) in Alternaria brassicicola, plays a central role in pathogenicity against host cabbage plants. In this research, we further characterized the role of AbSte7 in the pathogenicity of this fungus using ${\Delta}AbSte7$ mutants. Disruption of the AbSte7 gene of A. brassicicola reduced accumulation of metabolites toxic to the host plant in liquid culture media. The ${\Delta}AbSte7$ mutants could not efficiently detoxify cruciferous phytoalexin brassinin, possibly due to reduced expression of the brassinin hydrolase gene involved in detoxifying brassinin. Disruption of the AbSte7 gene also severely impaired fungal detoxification of reactive oxygen species. AbSte7 gene disruption reduced the enzymatic activity of cell walldegrading enzymes, including cellulase, ${\beta}$-glucosidase, pectin methylesterase, polymethyl-galacturonase, and polygalacturonic acid transeliminase, during host plant infection. Altogether, the data strongly suggest the MAPKK gene AbSte7 plays a pivotal role in A. brassicicola during host infection by regulating multiple steps, and thus increasing pathogenicity and inhibiting host defenses.

• Entomological Research
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• v.48 no.5
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• pp.400-404
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• 2018

In this study, we investigated resistance to the organophosphates chlorpyrifos in Tunisian populations of Culex pipiens pipiens. Three field populations were collected from Northern and central Tunisia between 2003 and 2005 and used for the bioassays tests. Our results registered moderate and high levels of resistance to chlorpyrifos which ranged from 33.8 to 111. The chlorpyrifos resistant populations were highly resistant to propoxur indicated an insensitive acetylcholinesterase 1 (AChE 1). The highest frequency of AChE 1 resistant phenotypes (64%) was recorded in the most resistant population (sample # 1). Bioassays conducted in the presence of synergists showed that not esterases were involved as the resistance mechanism to chlorpyrifos. However, CYP450 was partly involved in the resistance of the most resistant sample (# 1). Starch electrophoresis showed that three esterases were present in studied samples: A2-B2, A4-B4 and B12. Results are discussed in relation to the selection pressure caused by insecticide treatments.