• Journal of Microbiology and Biotechnology
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• v.16 no.11
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• pp.1760-1772
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• 2006

Mature acetylcholinesterase (AChE) gene (gm, 1,836 bp) was cloned from the housefly and successfully expressed in the E. coli CodonPlus (DE3) RIL system (GM-E, 72 kDa) with a yield of 1,630 mU/g fresh cells. Using the gm, 10 kinds of mutants were constructed and expressed for enhancing sensitivity to insecticides. The sensitivity of these mutants to five kinds of organophosphate (OP) and three carbamate insecticides was investigated by measuring the apparent bimolecular inhibition constant ($k_i=k_2/K_d$). Surprisingly, the sensitivity of quadruple mutant IGFT was enhanced as much as 7-fold for acephate, 164-fold for demeton-S-methyl, 484-fold for dichlorvos, 523-fold for edifenphos, 30-fold for ethoprophos, 30-fold for benfuracarb, 404-fold for carbaryl, and 107-fold for furathiocarb, compared with that of GM-E, although the sensitivity of each single point mutant was slightly increased. These mutational studies indicated that (i) contradictory to Walsh et al. [39], the residue 327 is the important key residue for enhancing sensitivity as much as the residue 262, (ii) the residue 82 and additional residues of 234, 236, and 585 are also important, and (iii) sensitivity was cooperatively accelerated as the number of strategic mutations increased.

• The Korean Journal of Physiology and Pharmacology
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• v.16 no.5
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• pp.355-360
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• 2012

A simple, sensitive and reproducible high-performance liquid chromatography (HPLC) method has been validated for determining concentrations of glutamate, glycine, and alanine in human plasma. Proteins in plasma were precipitated with perchloric acid, followed by derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC). Simultaneous analysis of glutamate, glycine, and alanine is achieved using reversed-phase HPLC conditions and ultraviolet detection. Excellent linearity was observed for these three amino acids over their concentration ranges with correlation coefficients (r)>0.999. The intra- and inter-day precision were below 10%. This method utilizes quality control samples and demonstrates excellent plasma recovery and accuracy. The developed method has been successfully applied to measure plasma glutamate, glycine, and alanine in twenty volunteers.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.24-31
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• 1998

This study was performed to investigate the difference in species of test fish on the determination of short-term bioconcentration factor in zebrafish(Brachydanio rerio), red sword tail(Xiphophorus hellieri) and goldfish(Carassius auratus). Experimental concentrations of carbamates were 0.05 and 0.10 ppm and chlorothalonil were 0.005 and 0.01 ppm for 3 and 5 days, respectively. This paper reports the measured BCF value on pesticides in various species of test fish, under steady state, and examined correlation between the BCF value and depuration rate constant or LC$_{50}$ or lipid content. Carbamates and chlorothalonil concentration in fish extract and BCF of carbamate and chlorothalonil were increased as incresing test concentration. Carbamates concentration in fish extract and BCF of carbamate were decreased as incresing test period, but chlorothalonil concentration in fish extract and BCF of chlorothalonil were increased as prolonging test period. Determined pesticide concentration in fish extract and BCF were highest in red sword tail, and followed by goldfish, and zebrafish. Determined depuration rate constant were highest in zebrafish, and followed by goldfish, and red sword tail. 96hr-LC$_{50}$ were highest in red sword tail, and followed by zebrafish, and goldfish. Lipid compositions were highest in red sword tail, and followed by goldfish, and zebrafish. Therefore, it is suggested that the difference of BCF between each pesticide due to those of lipid composition of fish and deputation rate constant, while LC$_{50}$ have no effect on BCF.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.380-385
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• 2009

The absorption rate of carbon dioxide with 2-amino-2-methyl-1-propanol(AMP) was measured in such non-aqueous solvents as methanol, ethanol, n-propanol, n-butanol, ethylene glycol, propylene glycol, and propylene carbonate, and in water at 298 K and 101.3 kPa using a semi-batch stirred tank with a plane gas-liquid interface. The overall reaction rate constant, obtained under the condition of fast reaction regime, from the measured rate of absorption was used to get the elementary reaction rate constants in complicated reactions represented by reaction mechanism of carbamate formation and the order of overall reaction of $CO_2$ with amine. The correlation between the elementary reaction rate constant and the solubility parameter of the solvent was also presented.

• Archives of Pharmacal Research
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• v.14 no.4
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• pp.330-335
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• 1991

The effects of physostigmine and neostigmine on the parathin induced toxicity were examined in adult female rats. Physostigmine $(100\;{\mu}g/kg,\;ip)$ or neostigmine $(200\;{\mu}g/kg,\;ip)$ inhibited acetylcholinesterase (AChE) and cholinesterase (ChE) activities in blood, brain and lung when the enzyme activity was measured 30 min after the treatment. At the doses of two carbamates equipotent on brain AChE, neostigmine showed greater inhibition on peripheral AChE/ChE. The enzyme activity returned to normal in 120 min following the carbamates except in the lung of rats treated with neostigmine. Carbamates administered 30 min prior to parathion (2 mg/kg) antagonized the inhibition of AChE/ChE by parathion when the enzyme activity was measured 2 hr following parathion. Neostigmine showed greater protective effect on peripheral AChE/ChE. The effect of either carbamate on AChE/ChE was not significant 2 hr beyond the parathion treatment. Carbamates decreased the mortality of rats challenged with a lethal dose of parathion (4 mg/kg, ip) either when treated alone or in combination with atropine (10 mg/kg, ip). Lethal action of paraoxon (1.5 mg/ks ip), the active metabolite of parathion was also decreased by the carbamate treatment indicating that the protection was not mediated by competitive inhibition of metabolic conversion of parathion to paraoxon. The results suggest that carbamylation of the active sites may not be the sole underlying mechanism of protection provided by the carbamates.

• Environmental Engineering Research
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• v.24 no.1
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• pp.137-143
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• 2019

In this study, extraction, clean-up and instrumental analytical conditions were optimized for identifying and quantifying methyl-, chloromethylbenzi-, octyl- isothiazolinone (MIT, CMIT, BIT, OIT) and 3-iodo-2-propynyl butyl carbamate (IPBC), widely used biocidal active ingredients in human hygiene consumer products. Accuracy of the developed ultrasonic assisted extraction method followed by HPLC/MS analysis for four isothiazolinones and IPBC ranged between 60.4% and 113% in various types of consumer product samples. Method detection limits ranged 0.011-0.034 mg/kg for wet wipes, 0.57-1.5 mg/kg for liquid detergent and 0.58-1.6 mg/kg for powder detergent. Wet wipes, powder and liquid detergents collected from local market in Korea were analyzed to demonstrate the applicability of the developed method. Even after the regulation of those compounds in wet wipes, CMIT, MIT and IPBC were still frequently detected from complementary wet wipes without brand labels which were distributed to customers at local retail shops and restaurants. The maximum observed concentrations of MIT and CMIT found in those complementary wet wipes were 70.2 mg/kg and 11.3 mg/kg, respectively.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.353-360
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• 2003

For the simple rapid bioassay of organophosphorus and carbamate pesticide residues, a mass-production system of acetycholinesterase (AChE, EC 3.1.1.7, MAChE) using baculovirus and insect cell culture was constructed. The cDNA for AChE was synthesized from Drosophila melanogaster in Halla Mountain, the lipid anchor tail was removed by PCR and was used for the site-directed mutagenesis of three amino acid residues (E107Y, F368L, L408F). The mutated cDNA was inserted into the baculovirus vector and expressed in insect cells. Maximum cell growth and enzyme activity were reached when the cells $(2{\times}10^6\;cell/ml)$ were infected four times at four-day-intervals. His-tag containing MAChE was purified using Ni-NTA column and used for characterization. The activity was maintained under various pHs (3-10) and temperatures $(20-50^{\circ}C)$ under experimental conditions. As an extraction solution for pesticides, methanol is more effective than ethanol. Against major organophosphate and carbamate pesticides, the MAChE showed better sensitivity than AChE and AChE from housefly (Taiwan).

• Korean journal of applied entomology
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• v.14 no.2 s.23
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• pp.65-70
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• 1975

The study was planned to detect resistance levels of striped rice borers (Chilo suppressalis Walker) and green rice leafhoppers(Nephotettix cincticeps Uhler) from different localities to organophosphate and carbamate insecticides using topical application. Strains of overwintering striped rice borers were collected from 7 different areas in Gyeonggi Province and they were kept under conditions of about $25^{\circ}C$ for 10 days. Overwintered and reared larvae of striped rice borers were compared for response to insecticides. The strains of green rice leafhopper were collected from Iri, Milyang, Pyongtaek, Echeon and Suweon. Insects were multiplied in the lab. All insecticides tested were organphosphates(MPP, MEP and Diazinon) and carbamate (NAC), which have been used in control of rice insect pests for over past 10 years. The results obtained were as follows; a. With MPP compound, resistant levels of the Joam, Suweon, and Echeon strains of C. suppressalis were from 2 to 4 times as compared with the Yangpyong strain. b. With MEP insecticide, resistant levels of the Kimpo, Pyongtaek, Yongin, Echeon, Suweon, and Joam strains of C. suppressalis were from 2 to 6 times as compared with the Yangpyong strain. c. With Diazinon, resistant levels of the Suweon strain of C. suppressalis were 3 times greater than the Yangpyong strain; but the resistant levels of Kimpo, Pyongtaek, Yongin, and Echeon strains approximated the later. 4. The overwintered larvae of C. suppressalis were more tolerant to the insecticides than the larvae reared in the lab. e. With MEP, resistant levels of the Iri, Milyang, and Pyongtaek strains of N. cincticeps to the Suweon strain showed 13, 8, 7 and4 times, respectively. f. With MPP, resistant levels of the Iri and Pyongtaek strains of N. cincticeps were 7 and 4 times as compared with the Suweon strain, respectively. g. With NAC, resistant levels of the several strains of if. cincticeps showed no difference, and seemed not to have developed resistance yet.

• Korean Journal of Environmental Agriculture
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• v.1 no.1
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• pp.14-21
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• 1982

Analytical methods for residues of six N-methylcarbamate insecticides were investigated to compare the minimum detectability, recovery from several crops and feasibility of multiple residue analysis. Those methods studied in this work included spectrophotometry by diazotization and gas chromatography by N-trifluoroacetylation(TFA), pentafluorobenzylether(PFB) and dinitrophenylether (DNP) derivatization. Maximum absorbed wavelength of the diazotized MIPC, XMC, BPMC, propoxur and carbofu ran was around 460 ㎚, while that of carbaryl recorded 510 ㎚. Recovery from brown rice and apple by diazotization method ranged from 80 to 120% and minimum detectable limits were 0.03 to 0.05 ppm in 50 g of the sample. Minimum detectability of PFB derivatives by gas chromatography was superior to TFA and DNP derivatives. DNP derivatives showed the longest retention time among the given derivatives. Recovery from crops by gas chromatographic met hod ranged 74 to 94%, 78 to 93%, and 85 to 99% in brown rice, rice straw and apple, respectively. Limit of detection was 0.01 ppm for TFA, 0.005 ppm for PFB and 0.02 ppm for DNP derivatives in 50 g of the crop samples.

• Food Science and Preservation
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• v.20 no.3
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• pp.429-434
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• 2013

This study was designed to investigate the formation of ethyl carbamate (EC) during the ripening of Maesil with sugar and Soju (19.5~35% alcohol contents) using a homemade method. Maesil, sugar and Soju were purchased at ordinary market in June of 2012. The preparation of sample for analysis was conducted by method of Henry et al. The analysis of GC/MS was used SIM mode (m/z 89, 74, 62). Quantification was performed in terms of the 62 ion and was based on an internal standard procedure. Good linearity was obtained with a regression coefficient ($r^2$ = 0.993). Low detection limits (LOD) was achieved 4.31 ug/kg and recovery for alcohol was 74.8%. During 90 days, fermentation with sugar was not detected EC (under LOQ). 15 days ripened Maesil wine contained EC between non detected~32.7 ug/kg and 90 days ripened Maesil wine was 19.7~87.4 ug/kg. Higher proportion of Maesil and Soju increased EC contents. EC levels were increased 32.7 ug/kg to 87.4 ug/kg in the ratio of Maesil to 35% alcohol-Soju (1:1). In the ratio of Maesil to 35% alcohol-Soju (1:3) was increased non detected to 69.7 ug/kg. After 90 days, Maesil wine was filtered Maesil through a seive and ripened by 180 days to investigate the formation of EC compared with non filtered. Treatment of filtered, EC contents was much higher level compared with non filtered. Therefore, this result showed that alcohol contents contribute to increase EC formation more than Maesil.