• The Korean Journal of Pesticide Science
• /
• v.2 no.1
• /
• pp.12-17
• /
• 1998

Salicylic acid and 3-hydroxy benzoic acid are nitrated and esterified with some alcohols. Five phosphate and six carbamate compounds of alkyl-5-nitrosalicylate and alkyl-3-hydroxy-4-nitrobenzoate are synthesized by reacting alkyl-5-nitrosalicylate and alkyl-3-hydroxy-4-nitrobenzoate with diethyl-chlorophosphate and methyl isocyanate. As the bioassay results of synthesized compounds on five insects and six pathogens, the brown planthopper (BPH, Nilaparvata lugens) mortality of O-(2-carbomethoxy-4-nitrophenyl) O,O-diethylphosphate and O-(2-nitro-5-carbo methoxyphenyl) O,O-diethylphosphate was 96%, while four compounds including O-(2-carbo-(2-chloroethoxy)-4-nitrophenyl) O,O-diethylphosphate showed more than 95% of fungicidal activity on rice blast.

• Applied Biological Chemistry
• /
• v.49 no.4
• /
• pp.315-321
• /
• 2006

Inhibitors of acetylcholinesterase(AchE), such as organophosphates and carbamates, interfere the action of AchE in nerve and may lead to a severe impairment of nerve functions or even death. Therefore, insect AchE is the biological target of predominant insecticides used in agriculture. Biosensors are sensitive and can be used as dispoisable sensors for environmental control. In recent years, the use of AchEs in biosensor technology has gained enormous attention, in particular with respect to insecticide detection. The principle of biosensors using AchE as a biological recognition element is based on the inhibition the catalytic activity by the agents to be detected. We here present a strip-type biosensor based on AchE inhibition. In this study, acetylcholinesterase and PVA-SbQ(polyvinyl alcohol functionalized with methyl pyridinium methyl sulfate) were co-immobilized on immobilone-P membranes. Immobilization of the enzymes showed a stability in 6 months without activity loss in $4^{\circ}C$ storage. Enzymes immobilized on surfaces of membrane responded to organophosphates and carbamate more sensitivitive than enzyme in solution. Organophosphates and carbamates concentrations could be detected by entrapped and surface immobilized enzymes, in 5 min. For chlorpyrifos, carbofuran, cabaryl, and methidathion, the detection limits of AChE-strip were similar to that of HPLC/GC method.

• The Korean Journal of Pesticide Science
• /
• v.2 no.1
• /
• pp.24-31
• /
• 1998

Chemical derivative synthesis of ricinine, an active compound of Ricinus communis which showed high mortality against brown planthopper (Nilaparvata lugens), was performed to improve its pesticidal activity and the toxicity of 12 synthetic derivatives against major insect pests and phytopathogenic fungi were examined. Carbamate derivatives of ricinine could be synthesized from the precursor of ricinine, chloronorricinine and norricinine, whereas the derivatives were not synthesized from chlororicinic acid and ricinic acid having ketone group of pyridine ring. In organophosphates, reaction with oxon type of phosphate gave better yield than thiono type. Among the organophosphate derivatives of ricinine, thiono type of derivative structure gave $96.3%{\sim}100%$ mortality of the brown planthopper and the two-spotted spider mite (Tetranychus urticae) at 500 ${\mu}g/ml$ level. On the other hand, carbamate derivatives did not show insecticidal activity. In the fungicidal activity of ricinine derivatives, the derivative having amino radical at the 2 position of ricinine gave 85 to 100% of mycelium growth inhibition effect against ten major plant pathogens at the 200 ${\mu}g/ml$ level. In particular, the control value of the derivative on the rice blast (Pyricularia grisea) and barley powdery mildew (Erysiphe graminis) at the 250 ${\mu}g/ml$ level in vivo under greenhouse conditions was 92% and 96%, respectively.

• The Korean Journal of Pesticide Science
• /
• v.6 no.4
• /
• pp.264-270
• /
• 2002

Studies on the resistance monitoring of green peach ahpid, Myzus persicae, its development pattern by artificial selection with imidacloprid and cross-resistance were carried out to develope resistance management strategy. Resistance ratios of M. persicae collected at Hwachon and Dunnae among 5 locations in alpine cultivation area appeared to be high as 37.2 and 16.5, respectively. Resistance of aphid to imidacloprid developed slowly up to 20 time selection, and after that it grew quickly. Imidacloprid-resistant aphid strain showed low cross-resistance ratios(<10) to most of organophosphates, carbamates, and mixed insecticides except pirimicarb(487.8), but high ratios to acetamiprid(143.0) which is one of the neonicotinoids like imidacloprid, and pyrethroids such as deltamethrin(14.9), flucythrinate(12.9) and halothrin(15.9).

• Environmental Analysis Health and Toxicology
• /
• v.18 no.1
• /
• pp.21-25
• /
• 2003

카바메이트계 농약인 카보푸란은 어류에 대한 독성이 매우 높으며, 낮은 농도에서 어류의 척추기형이나 행동이상을 유발한다. 이러한 카보푸란의 독성기전을 밝히기 위한 일환으로 신경물질대사와 관련이 깊은 acetylcholine esterase(AChE)와 monoamine oxidase(MAO)에 미치는 농약의 효과를 송사리(Oryzias latipes; Medaka fish)를 이용하여 평가하였다. Medaka fish에 대한 카보푸란의 반수치사농도(LC$_{50}$)는 2.5 ppm이었으며, 1 ppb 카보푸란에 24시간 노출된 경우, AChE 효소활성이 머리와 몸통부위에서 각각 30, 20%씩 감소되었다. 한편, MAO 효소활성은 카보푸란의 농도가 증가함에 따라 머리부위에서는 감소한 반면, 몸통부위에서는 증가하는 경향을 보였다. 특히 카보푸란의 농도가 1 ppb에서도 송사리의 MAO 효소활성이 영향을 받는 것으로 나타나, 카보푸란에 의한 송사리의 행동이상은 AChE 활성 뿐 아니라 MAO활성의 변화에 의한 복합적인 효과일 가능성이 높다.

• The Korean Journal of Pesticide Science
• /
• v.11 no.3
• /
• pp.171-178
• /
• 2007

Esterase isozymes were extracted from final instar larvae of M. saltuarius treated with selective diets and inhibitors. Twenty esterase isozymes were separated on 12% native-PAGE gel and stained with three different substrates(${\alpha}$-naphthyl acetate, ${\beta}$-naphthyl acetate, or ${\alpha}$-naphthyl butyrate). Interestingly, the isozymes of Est7(${\alpha}$-naphthyl acetate and ${\alpha}$-naphthyl butyrate) and Est6(${\beta}$-naphthyl acetate) were specifically activated in final instar larvae fed with the bark of Pinus koraiensis. However, we could not find any band from substrate ${\beta}$-naphthyl stearate. The esterase activities of Est3, Est6, and Est7 were inhibited by organophosphate and carbamate insecticides. In addition, The esterase activities of Est4, Est6, and Est7 were also inhibited by eserine. However, inhibition of esterase activities in methoprene, bornyl acetate, linal, cineol, and citral was not observed. However, It is necessary to reconfirm these results in vivo.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.9 no.2
• /
• pp.87-92
• /
• 2001

As well as arising the concern about pesticides known as a Carcinogenic or endocrine disorder substrates, magnitude was increased of reducing pesticides in soil or water. In this work, removals of residual pesticides on surface of solid phase were attempted by the photooxidation process with hydrogen peroxide. The optimum conditions for the removals of benomyl (carbamatic pesticide) chlorothalonil (Organochoric pesticide) were 350nm UV wavelegth and 20% (v/v) hydrogen peroxide solution as oxidant. Removals are negligible when UV radiation or the supply of hydrogen peroxide are solely applied on the target compoounds. Removal rates of the pesticides are accelerated by UV radiation with hydrogen addition. After 20 min of the treatment, about $2{\mu}g/cm^2$ of benomyl and $1,88{\mu}g/cm^2$ of chlorothalonil were disappeared on the surface of the solid phase.

• The Korean Journal of Pesticide Science
• /
• v.15 no.3
• /
• pp.238-245
• /
• 2011

This study was carried out to examine residual pesticides in dried agricultural products collected from Gyeonggi province in 2010. A total of 102 samples was collected and analyzed for 206 pesticides by multiresidue method using GC-${\mu}ECD$, GC-NPD, GC/TOF/MSD, HPLC-UVD, HPLC-FLD and HPLC/MS/MS. The detection rate of residual pesticides was 23.5% (24 of 102 samples) and the agricultural products exceeding their MRLs (Maximum Residue Limits) were 1 sample of pepper leaves. Additionally, the frequently detected pesticide were chlorothalonil, fenvalerate, chlorpyrifos, endosulfan, bifenthrin, cypermethrin, hexaconazole and iprodione. The pesticide types detected in the dried agricultural products showed in the descending order of organophosphorus (22%), pyrethroid (22%), organochloride (17%), dicarboxymide (11%), carboxymide (6%), carbamate (6%), triazole (5%) and the others (11%).

• Korean Journal of Environmental Agriculture
• /
• v.18 no.2
• /
• pp.154-163
• /
• 1999

A multiresidue method(MRM) for pesticides must be rapid and must test a wide variety of pesticides at relevant toxicological concentrations. In this study, three kinds of major analytical methods such as Korean Food Code Method, CDFA MRM, and Holstege's method are tested to compare the average recoveries, solvent consumption, and required time for the analysis of 18 organochlorines, 18 organophosphates, and 6 carbamates in spinach samples. Samples for pesticides analysis were extracted and cleaned up according to the respective methods and detected by gas chromatography with selective detectors, ECD and NPD, HPLC with postcolumn reaction system(PCRS). Average recovery of 42 pesticides by Korean Food Code method, CDFA method, and Holstege's method were 91.3%, 88.1%, 89.0%, respectively. Amount of solvent consumption and required time for the analysis of Korean Food Code method were from two and a half times to three times as much as those of another two methods. For the development and legal application of more rapid and effective MRMs, prolonged study is necessary.

• Korean Journal of Environmental Agriculture
• /
• v.7 no.2
• /
• pp.117-123
• /
• 1988

This study was initiated to understand the mechanism of selective toxicity of diazinon and carbofuran to killifish and loach. Conventional LC50 was calculated from fish test. IC50 with acetylcholinesterase activity was estimated using whole body and wet brain homogenate of the two fish species. Acetylcholinesterase activity of killifish was approximately twice as high as that of loach. The selective toxicity of diazinon to killifish and loach was partly (14 : 4) explained by the IC50 of diazoxon, a toxic metabolite of diazinon. IC50 of carbofuran also partly (14 : 3.4) contributed to the selectivity. These result suggested that the enzymatic method might be utilized as a screening tool for the chemicals affecting fish species of environmental concern with certain limitations which should be overcome in future studies.