• Korean journal of applied entomology
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• v.40 no.3
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• pp.265-271
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• 2001

Resistance mechanisms in the green peach aphid (Myzus persicae) resistant to imidacloprid were investigated. Imidacloprid residues on the aphid integuments decreased slowly as time passed with no significant difference between the susceptible and resistant strains. Residue in the aphid body increased in both strains with time elapse, and was slightly more in the susceptible strain. A higher metabolic rate of imidacloprid in the resistant strain can be expected by the fact that more amount of imidacloprid were excreted in the resistant strain than in the susceptible one. The activity of AChE was higher 1.4 times in the resistant strain than in the susceptible one, and imidacloprid did not inhibit AChE at all in both strains. Piperonyl butoxide (PBO) and iprobenfos (IBP) synergized imidacloprid activity. The mixtures of imidacloprid and PBO (1 : 1 and 1 : 5) caused 69.4- and 250-fold increase of imidacloprid toxicity against the aphid. Insecticide toxicity of the mixtures of IBP and imidacloprid (1 : 1 and 1 : 5) was also increased 227 and 80.6 times. Esterase activity when $\alpha$-naphtyl butyrate and $\beta$-naphtyl acetate were used as substrates was higher in the resistance strain than in the susceptible one. This means that P450 monooxygenase and esterase are responsible for the resistance to imidacloprid in this aphid strain.

• Environmental Analysis Health and Toxicology
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• v.18 no.2
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• pp.155-163
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• 2003

Fluoranthene, a common polycyclicaromatic hydrocarbon (PAH), exhibits phototoxicity which may affect aquatic organisms. The eventual goal of this study is to develop a biomarker of Japanese medaka (Oryzias latipes) used in monitoring hazardous chemicals in the ecosystem. In this study we investigated neural toxicity of fluoranthene in Japanese medaka (Oryzias latipes) along with comparative analysis of corresponding behavioral response. The untreated individuals shooed normal behavioral characteristics (i. e., smooth and linear movements). The treated fish, however, showed stopping and abrupt change of orientation (100 ppb), and severely reduced locomotive activity and enhanced surfacing activity (1,000 ppb). Treatment of the medaka fish with fluoranthene caused a significant suppresson of acetycholine esterase (AChE) activities in the body portion but not in the head portion. When fish were exposed to 1,000 ppb of fluoranthene for 24 hr, the body AChE activities decreased from 126.${\pm}$31.89 (nmoles substrate hydrolyzed per min per mg protein) to 49.51${\pm}$11.99. Expressions of tyrosine hydroxylase (TH) protein in the different organs from both head and body portions were comparatively analyzed using an immunohistochemical technique. Five organs of the medaka fish showing a strong TH protein expression were the olfactory bulb, hypothalamus, optic lobe, pons and myelencephalon regions. This study provides molecular and neurobehavioral bases of a biomonitoring system for toxic chemicals using fish as a model organism.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2247-2250
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• 2012

Two new bibenzyl glucosides, 3,3',4',5-tetramethoxybibenzyl-4-O-${\beta}$-D-glucopyranoside (1) and 3,4,4',5-tetramethoxybibenzyl-3'-O-${\beta}$-D-glucopyranoside (2), together with five known ones, chrysotobibenzyl (3), erianin (4), chrysotoxine (5), gigantol (6) and tristin (7) were isolated from the stems of Dendrobium chrysotoxum. The structures of those compounds were elucidated by extensive spectroscopic analysis. Moreover, compounds 1-7 were assessed for inhibitory activity of two enzymes-AChE (acetylcholine esterase) and BChE (butyrylcholine esterase).

• Journal of Applied Biological Chemistry
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• v.43 no.4
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• pp.185-191
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• 2000

Pest insect control is dependent on about 200 insecticides that work by relatively few mechanisms. The targets they disrupt are mostly involved in the nervous system, respiratory chain, growth and development, or the gut. The major nerve targets are: acetylcholinesterase for the organophosphates and methylcarbamates; the nicotinic acetylcholine receptor for the neonicotinoids; the $\gamma$-aminobutyric acid receptor for several chlorinated hydrocarbons and fipronil; the voltage-gated sodium channel for DDT and pyrethroids. Selection of resistant strains often confers cross-resistance to some or all other insecticides working at the same site. The toxicological properties of different compounds acting on the same target are increasingly considered together, summating the risk even though the compounds are of quite diverse chemical types. Continuing attention is also being given to secondary targets not involved in the primary mechanism of toxicity but instead in side effects that must be considered in the overall safety evaluation. Research on insecticide targets is important in learning to keep up with resistance and changing concepts and policies on safety. These relationships are illustrated by recent studies in the Environmental Chemistry and Toxicology Laboratory of the University of California at Berkeley.

• Molecules and Cells
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• v.38 no.9
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• pp.796-805
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• 2015

Gintonin is a novel ginseng-derived lysophosphatidic acid (LPA) receptor ligand. Oral administration of gintonin ameliorates learning and memory dysfunctions in Alzheimer's disease (AD) animal models. The brain cholinergic system plays a key role in cognitive functions. The brains of AD patients show a reduction in acetylcholine concentration caused by cholinergic system impairments. However, little is known about the role of LPA in the cholinergic system. In this study, we used gintonin to investigate the effect of LPA receptor activation on the cholinergic system in vitro and in vivo using wild-type and AD animal models. Gintonin induced $[Ca^{2+}]_i $ transient in cultured mouse hippocampal neural progenitor cells (NPCs). Gintonin-mediated $[Ca^{2+}]_i $ transients were linked to stimulation of acetylcholine release through LPA receptor activation. Oral administration of gintonin-enriched fraction (25, 50, or 100 mg/kg, 3 weeks) significantly attenuated scopolamine-induced memory impairment. Oral administration of gintonin (25 or 50 mg/kg, 1 2 weeks) also significantly attenuated amyloid-${\beta}$ protein ($A{\beta}$)-induced cholinergic dysfunctions, such as decreased acetylcholine concentration, decreased choline acetyltransferase (ChAT) activity and immunoreactivity, and increased acetylcholine esterase (AChE) activity. In a transgenic AD mouse model, long-term oral administration of gintonin (25 or 50 mg/kg, 3 months) also attenuated AD-related cholinergic impairments. In this study, we showed that activation of G protein-coupled LPA receptors by gintonin is coupled to the regulation of cholinergic functions. Furthermore, this study showed that gintonin could be a novel agent for the restoration of cholinergic system damages due to $A{\beta}$ and could be utilized for AD prevention or therapy.

• Archives of Pharmacal Research
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• v.23 no.3
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• pp.222-225
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• 2000

A series of conformationally controlled 2-PAM derivatives were prepared from 2-acetylpyridine and 2,3-pyrido[b]cycloalkenones in two steps and their reactivities towards parathion poisoned AChE were evaluated. The most planar 2,3-pyrido[b]cyclohexanone oxime methiodide showed an activity comparable to 2-PAM Implying E-syn is that the most active comformation of 2-PAM in the biological system.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.2
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• pp.228-235
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• 2010

This study was performed to investigate the memory enhancing effect of Poria cocos Wolf (Hoelen cum radix) against scopolamine-induced amnesia in Sprague-Dawley (SD) rats. To induce amnesia, scopolamine (0.75 mg/kg) was intraperitonically injected into SD rats 30 min before starting behavior tests. We have conducted Morris water-maze and Y-maze tests to monitor learning and memory functions. Poria cocos effectively reversed scopolamine-induced memory impairment in SD rats which was represented by an improvement of mean escape latency in water-maze test and spontaneous alterations in Y-maze test. To elucidate possible molecule mechanism, we have measured mRNA as well as protein expression of acetylcholine esterase (AchE), choline acetyltransferase (ChAT), muscarinic acetylcholine receptor (mAchR), and brain-derived neurotrophic factor (BDNF) using RT-PCR and Western blot analysis, respectively. Poria cocos increased mRNA levels of ChAT and mAchR in rat hippocampus compared with those in the scopolamine-injected amnesic group. In addition, protein expression of ChAT and BDNF was also elevated by Poria cocos intake. Furthermore, as an upstrem regulator, the activation of cAMP response element-binding protein (CREB) was assessed by immunohistochemistry. In this immunohistochemical analysis, the phosphorylation of CREB (p-CREB) was reduced by scopolamine injection, which was restored back to control levels by administration of Poria cocos. These results suggest that Poria cocos may improve memory and cognitive deficit in amnesia and have therapeutic potentials through up-regulation of ChAT, mAchR, and BDNF, which seemed to be mediated by activation of CREB.

• Natural Product Sciences
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• v.22 no.4
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• pp.225-230
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• 2016

Phytochemical investigation from the stem bark of Beilschmiedia pulverulenta resulted in the isolation of five lignans, (+)-yangambin (1), (+)-sesartemin (2), (+)-excelsin (3), (+)-sesamin (4), and (+)-syringaresinol (5), together with lupeol (6), lupenone (7), ${\beta}-sitosterol$ (8), and ${\beta}-sitostenone$ (9). Their structures were established by the analysis of their spectroscopic (1D and 2D NMR) and spectrometric (MS) data, as well as by comparison with those reported in the literature. The isolated lignans were tested for their anticholinesterase (AChE: acetylcholine esterase and BChE: butyryl cholineesterase) and anti-inflammatory (COX-2: cyclooxygenase-2 and LOX: lipoxygenase) activities. All the isolated lignans (1 - 5) exhibited significant inhibition activities in AChE/BChE and COX-2/LOX assays with $IC_{50}$ values ranging from $168.8-504.2{\mu}M$ and $21.0-59.4{\mu}M$, respectively.

• Environmental Analysis Health and Toxicology
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• v.23 no.3
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• pp.171-178
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• 2008

수백여 종의 개별물질이 불완전 연소 혹은 유기물의 열분해로 인해 발생되는 다환방향족 탄화수소(PAHs)는 환경에서 중요한 오염원이 되고 있다. 본 연구는 다양한 바이오마커를 이용하여 수서생태계에 벤조피렌(benzo[a]pyrene)과 같은 다환방향족 탄화수소의 영향을 분석하였고, 이에 대한 통합적 결과 모델을 도출하였다. 즉, 잉어(Cyprinus carpio)를 이용하여 여러 농도의 벤조피렌(3, 12, $34{\mu}g/L$, 측정농도 기준)에 10일간 노출시킨 다음, DNA single-strand break, ethoxyresorufin-O-deethylase (EROD), acetylcholine esterase (AChE)와 vitellogenin (VTG)의 농도를 측정하였다. 벤조피렌은 잉어의 DNA 손상을 유도하였고, 낮은 농도에서 EROD와 VTC의 유의적인 활성을 보였으나, 신경전달물질과 관련이 깊은 AChE 효소활성에는 영향을 미치지 않았다. 이 결과를 star plot를 이용하여 통합 및 분석하였으며, 노출농도에 따른 통합 반응지수(integrated biomarker response value: IBR)로 나타내었다. 이런 다양한 바이오마커의 결과들은 벤조피렌에 대한 어류의 영향과 수생태 모니터링 자료로 이용 가능할 것으로 여겨지며, 통합반응지수는 생태위해성평가에서 유용한 도구로 쓰일 가치가 있는 것으로 평가된다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.2
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• pp.131-136
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• 2016

Marine organisms are sources of many bioactive compounds, such as essential fatty acids, essential amino acids, vitamins, and minerals, making them useful candidates for the production of safe bioactive substances. They also synthesize glutamic acid, which can be used to produce γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system (CNS), via fermentation with Lactobacillus brevis BJ-20. This study investigated the degree to which fermented sea tangle (FST) inhibits enzymes such as acetylcholine esterase (AChE) and prolyl endopeptidase (PEP) and affects memory of normal mice using the T-maze test. FST inhibited more than 90% of AChE at 1 mg/mL and 50% of PEP at 8 mg/mL. Oral FST (100 mg/kg) significantly improved performance of normal mice on the T-maze. Therefore, sea tangle fermented with L. brevis BJ20 effectively contributes to memory improvement and might be a useful functional food ingredient.