• Journal of Applied Biological Chemistry
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• 제44권3호
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• pp.105-112
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• 2001

Insect pests can be controlled through direct application of insecticides. Insect control by residual protectants is relatively inexpensive and has an advantage of destroying all stages of infestations. The efficacy of control is largely determined by the concentration of insecticides to which the pest species is exposed. A reduction in the period of control in the field afforded by a specific level of a protectant indicates that resistance has developed. An increase in the level of protectant is required to maintain control, and the efficacy of currently used insecticides has been severely reduced by insecticide resistance in pest species. Development of resistance to particular insecticide varies with species because insecticide resistance is often correlated with increased levels of certain enzymes, which are cytochrome P450-dependent monooxygenases, glutathione S-transferases and esterases. Some sections of insecticide molecules can be modified by one or more of these primary enzymes. A reduction in the sensitivity of the action site of a xenobiotic also constitutes a mechanism of resistance. Acetylcholinesterase is a major target site for insecticide action, as are axonal sodium ion channels and ${\gamma}$-aminobutyric acid receptors. Development of reduced sensitivity of these target sites to insecticides usually occurs. This review not only may contribute to a better understanding of insecticide resistance, but also illustrates the gaps still present for a full biochemical understanding of the resistance.

• Journal of Biosystems Engineering
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• 제28권6호
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• pp.505-510
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• 2003

In Korea, due to its broad efficacy as a systemic insecticide, imidacloprid has been widely used in rice paddies to control sucking insects, soil insects, and some chewing insects and in apple orchards to control various insects pests. To quantify the imidacloprid residue concentrations, samples are assayed in vitro using enzyme-linked immunosorbent assays(ELISA). These assays generally require several hours to perform. As a biosensor, a competitive imidacloprid ELISA was modified to measure insecticide concentrations. It was found that a total assay time of 15 min(10-min antibody-antigen binding, and 5-min substrate development) is sufficient for monitoring imidacloprid concentrations. Further work is needed to improve the sensitivity of the measurement protocol.

• Food Science and Biotechnology
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• 제17권5호
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• pp.1038-1046
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• 2008

This study was carried out to develop a small-sized biosensor based on surface plasmon resonance (SPR) for the rapid identification of insecticide residues for food safety. The SPR biosensor module consists of a single 770 nm-light emitting diodes (LED) light source, several optical lenses for transferring light, a hemisphere sensor chip, photo detector, A/D converter, power source, and software for signal processing using a computer. Except for the computer, the size and weight of the sensor module are 150 (L)$\times$70 (W)$\times$120 (H) mm and 828 g, respectively. Validation and application procedures were designed to assess refractive index analysis, affinity properties, sensitivity, linearity, limits of detection, and robustness which includes an analysis of baseline stability and reproducibility of ligand immobilization using carbamate (carbofuran and carbaryl) and organophosphate (cadusafos, ethoprofos, and chlorpyrifos) insecticide residues. With direct binding analysis, insecticide residues were detected at less than the minimum 0.01 ppm and analyzed in less than 100 sec with a good linear relationship. Based on these results, we find that the binding interaction with active target groups in enzymes using the miniaturized SPR biosensor could detect low concentrations which satisfy the maximum residue limits for pesticide tolerance in Korea, Japan, and the USA.

• Journal of Biosystems Engineering
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• 제30권2호
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• pp.114-120
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• 2005

In this study, a biological reaction and measurement control system was developed to rapidly measure the insecticide imidacloprid residues in agricultural products. The biological reaction part of the system was designed to include micro-pumps and valves for fluid transport, and a polystyrene covet as a reaction chamber. The measurement control part of the system consisted of a photodiode with a light-emitting diode for optical density measurement, and a control microcomputer to implement assay. Signal output was read as the rate of change in optical density at 645 nm. The sensitivity of the system was 2.2 ng/mL ($IC_50$). The system could execute a measurement cycle in about 19 minutes. Research will be continued to develop an automatic sampler fur imidacloprid residues from agricultural products.

• Journal of Ecology and Environment
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• 제36권2호
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• pp.141-150
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• 2013

Natural zooplankton communities are composed of many different species at different trophic levels in the aquatic food web. Several researchers have reported that in mesocosm/enclosure experiments, larger cladocerans tend to be more sensitive to carbamate insecticides than smaller ones (Daphnia > Moina, Diaphanosoma > Bosmina). In contrast, results from individual-level laboratory tests have suggested that large cladoceran species are more tolerant than small species. To clarify this inconsistency, we conducted a microcosm experiment using model zooplankton communities with different species compositions, where animals were exposed to lethal (near to the 24 h LC50, concentration estimated to kill 50% of individuals within 24-h for the small cladoceran Bosmina) and lower, sublethal concentrations of carbaryl. In the experiment, population densities of the small cladocerans (Bosmina and Bosminopsis) decreased subsequent to the applications of chemical, but no impacts were observed on the large cladoceran Daphnia. Our results supported the reports of previous individual level toxicity tests, and indicated that the sensitivity of zooplankton to the insecticide was unchanged by biological interactions but the response of population can be modified by compensation of population through hatching from resting eggs and/or the persistence of insecticide in the systems.

• Journal of Microbiology and Biotechnology
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• 제16권11호
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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.

• 한국응용곤충학회지
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• 제30권2호
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• pp.117-123
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• 1991

벼멸구의 살충제 저항성 기구를 구명하고자 fenobucarb, carbofuran 및 diazinon으로 벼멸구를 14~18세대 누대 도태하여 얻어진 벼멸구를 대상으로 저항성 기구를 조사하였으며, 얻어진 결과중 acetylcholinesterase(AChE)와 esterase의 활성 변화에 대하여 보고하고자 한다. AChE활성은 fenobucarb선발 계통에서 1.6배 증가하였으나 타 계통에서는 차이가 없었고, 세포내 분포도 mitochondrial fraction에서 70% 이상으로 계통간 차이가 없었다. 반면, AChE감수성은 fenobucarb와 carbofuran선발 계통에서 각각의 공시 살충제에 대하여 12.2배, 5.6배 감소하였으나 diazinon선발 계통에서는 diazoxon에 대하여 1.7배 감소에 그쳤다. Esterase활성은 fenobucarb선발계통에서 5.6~6.8배, carbofuran선발계통에서 6.4~7.8배, diazinon선발계통에서 4.0~4.4배 증가하였다. 벼멸구의 저항성 증가에 다른 요인이 관련됨을 배제할 수 없으나, 본 실험 결과 esterase 활성증가와 AChE감수성 저하라는 두 요인이 상승적으로 작용하여 벼멸구 저항성을 유발하였음을 확인하였다.

• 한국응용곤충학회지
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• 제34권2호
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• pp.89-94
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• 1995

${LC}_{50}$에 의한 살충제 저항성 사험결과 지역에 따라 pirimicarb가 49~830배 phosphamidon이 31~536배, demeton S-methyl이 5~204배의 약제 저항성이 확인됨으로서 사과에 조팝나무진딧물이 포장에서 방제결과가 없는 난방제해충이 되었음을 알 수 있다. 이와 같이 약제에 따라, 지역에 따라 저항성차가 크게 나타나는 원인을 공시충을 채집한 과수원의 살충제 산포상황을 조사한 결과 저항성이 가장 높았던 예산과 이천-1의 개체군을 채집한 과수원에서는 살충제를 4회 이상산포하였고, 저항성이 가장 낮았던 개체별 esterase 활성을 활성지수별로 분포비율을 비교한 결과 활성지수가 원주는 낮은 곳에, 이천-1과 예산은 높은 곳에 집중적으로 분포하였으며, 효소의 활성지수로써 저항성도를 계산한 결과 원주는 44.5, 이천-1과 예산은 92.0이었고 기타의 개체군들은 약제산포회수가 적어 이 사이에 모두 분포하였음을 알 수 있어 포장에서 약제산포회수가 많을수록 효소의 활성이 높게 나타났고 저항성비도 높았다. 이들중 광주(조팝나무)를 S크론, 과천(사과)을 R크론으로 하여 AChE의 조해제에 대한 감수성을 조사한 결과 pirimicarb는 299.2배, phosphamidon은 186배나 저하되었다. 이로써 약제저항성이 높았던 크론에서 에스테라제의 활성이 높았고, AChE의 감수성이 저하되는 것으로 보아 조팝나무진딧물의 약제저항성기작에는 적오도 두가지 이상의 요인이 작용하고 있음이 확인되었다.

• Journal of Microbiology and Biotechnology
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• 제17권6호
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• pp.1002-1009
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• 2007

A rapid, convenient homogeneous competitive enzyme immunoassay for estimating the amount of fenthion is described. The assay utilizes glucose-6-phosphate dehydrogenase-hapten conjugates that are inhibited in solution by antibodies obtained from bovine serum albumin-hapten conjugates. In order to investigate the effects of bridging group recognition on the sensitivity of dose response characteristics, the bridging groups of varying alkyl chain length were attached at the phosphate position of fenthion. Among the antibodies used, the one obtained from the use of hapten (fenthion analog) with the same bridging group structure that was used in preparing the enzyme-fenthion conjugates showed maximum inhibition (up to 51.8%) in the absence of fenthion. In the presence of fenthion, the activity of the enzyme-hapten conjugate is regained in an amount proportional to the fenthion concentration. Under the optimized condition, the $ED_{50}$ value for fenthion was $0.809{\mu}g/ml$. The assay developed in this study is a rapid effective screening method for fenthion prior to precise analysis.

• 대한환경공학회지
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• 제27권2호
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• pp.191-197
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• 2005

Ceriodaphnia dubia를 이용한 새로운 독성시험법인 온도증가 단기독성평가법(ToxTemp, ToxCity test based on TEMPerature control)을 이용하여 농약성분에 대한 민감도를 조사하였다. BPMC, Diazinon, Fenitrothion등 하수의 생물학적 처리에 독성을 나타낼 수 있는 물질들에 대하여 기존의 실험방법인 표준 48시간 독성시험법과 비교했을 때 온도증가법은 $1{\sim}1.5$시간의 짧은 접촉시간에도 농약의 독성을 잘 감지할 수 있음을 알 수 있었다. 또한 중금속, 독성 유기화합물 그리고 농약성분을 비교, 평가했을 때 온도증가법은 1.25시간의 짱은 접촉시간 내에 48시간독성법의 결과와 높은 상관관계를 유지하며 독성을 감지하였다. 염색공단 폐수와 하수 등 실폐수에서의 독성평가능을 검토하기 위하여 활성슬러지를 이용한 질산화율, 산소이용율(OUR)과 C. dubia를 이용한 표준 48시간 독성시험법, 온도증가법을 비교하였다. 그 결과 OUR을 이용한 평가에서는 비교적 높은 질산화율 저해도를 보인 원수에 대해서도 독성민감도가 낮아 현장적용에 한계를 나타낸 반면 C. dubia를 이용한 표준 48시간 독성시험법과 온도증가법은 각기 다른 수준의 독성에 대해 민감하게 차이를 보였으며, 이 두 방법은 질산화율 저해도와 좋은 상관관계를 보였다. 온도증가법은 표준 48시간 독성시험법에 비해 1.5% 정도 민감도가 떨어지지만 현장에서의 신속한 감지가 가능하다는 점에서 현장에서의 질산화 독성진단에 대한 적용가능성이 높음을 보여주었다.