• 센서학회지
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• 제23권1호
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• pp.35-41
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• 2014

Microbes have been used extensively in various fields of researches and industries but has not been used widely for microfluidic biosensor applications because it is difficult to immobilize properly to a small space. Therefore, we developed a microbial immobilization method for microfluidic devices using single-walled nanotubes and dielectrophoretic force. Single-walled nanotubes and Escherichia coli were aligned between two cantilever electrodes by a positive dielectrophoretic force resulting in a film of single-walled nanotubes with attached Escherichia coli. The optimal condition of film formation without a cell lysis was investigated. Diameter of single-walled nanotubes and electric field (intensity and duration of application) had an effect on the cell viability. On the other hand, the cell concentration of the suspension did not affect the cell viability. Paraoxon was detected using single-walled nanotubes film with attached Escherichia coli that expressed organophosphorus hydrolase. This film which is suspended from the substrate showed faster response time than sensors that are not suspended from the substrate.

• 한국동물학회지
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• 제39권2호
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• pp.190-197
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• 1996

The optimal conditions and substrate specificity of whole body esterase (EST) activity, effects of inhibitors (Eserine, Paraoxon, p-HMB, DDVP, DFP) on the enzyme, and ontogenv of the isozymes were determined in Lucilio ilfustris Meisen. The optimal temperature was $45^{\circ}C$ regardless of kind of reacted substrate, $\alpha-naphthyl$ acetate $(\alpha-Nal,$ a.naphthvl butylate $(\alpha-N),$ and Pnaphthyl acetate $(\beta-Na),$ but the optimal pH showed some regioselectivitv to naphthvl group of the esters; PH 7.0 for Iform, pH 7.5 for a-form. The maximum reaction rate was recorded at about 2.5 $\times$ 10's M of PNa and etNa, but 1.0 $\times$ 10'S M of $\alpha-Nb.$ Among the five EST inhibitors tested, DDVP was the most powerful. However, distinction of the relative specificity of inhibitors between three body parts, head, thorax, and abdomen, was shouts, representing differences in the distribution and activity of isozvmes. Of 12 carboxyl-esterases (CE), 8 cholinesterases (ChE) and 2 arvlesterases (ArE) identified based on their inhibitor specificity throughout the development, two larval and prepupal stage specific ChEs, no pupal specific, and 2 CEs.2ChEs. and one ArE adult specific isozvmes were confirmed.

• Journal of Microbiology and Biotechnology
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• 제18권5호
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• pp.946-951
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• 2008

The opd gene, encoding organophosphorus hydrolase (OPH) from Flavobacterium sp. capable of degrading a wide range of organophosphate pesticides, was surface- and intracellular-expressed in Synechococcus PCC7942, a prime example of photoautotrophic cyanobacteria. OPH was displayed on the cyanobacterial cell surface using the truncated ice nucleation protein as an anchoring motif. A minor fraction of OPH was displayed onto the outermost surface of cyanobacterial cells, as verified by immunostaining visualized under confocal laser scanning microscopy and OPH activity analysis; however, a substantial fraction of OPH was buried in the cell wall, as demonstrated by proteinase K and lysozyme treatments. The cyanobacterial outer membrane acts as a substrate (paraoxon) diffusion barrier affecting whole-cell biodegradation efficiency. After freeze-thaw treatment, permeabilized whole cells with intracellular-expressed OPH exhibited 14-fold higher bioconversion efficiency ($V_{max}/K_m$) than that of cells with surface-expressed OPH. As cyanobacteria have simple growth requirements and are inexpensive to maintain, expression of OPH in cyanobacteria may lead to the development of a low-cost and low-maintenance biocatalyst that is useful for detoxification of organophosphate pesticides.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.1-14
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• 2023

The overuse of pesticides in agricultural sectors exposes people to food contamination. Pesticides are toxic to humans and can have both acute and chronic health effects. To protect food consumers from the adverse effects of pesticides, a rapid monitoring system of the residues is in dire need. Molecularly imprinted polymer (MIP) on a screen-printed electrode (SPE) is a leading and promising electrochemical sensing approach for the detection of several residues including pesticides. Despite the huge development in analytical instrumentation developed for contaminant detection in recent years such as HPLC and GC/MS, these conventional techniques are time-consuming and labor-intensive. Additionally, the imprinted SPE detection system offers a simple portable setup where all electrodes are integrated into a single strip, and a more affordable approach compared to MIP attached to traditional rod electrodes. Recently, numerous reviews have been published on the production and sensing applications of MIPs however, the research field lacks reviews on the use of MIPs on electrochemical sensors utilizing the SPE technology. This paper presents a distinguished overview of the MIP technique used on bare and modified SPEs for the detection of pesticides from four recent publications which are malathion, chlorpyrifos, paraoxon and cyhexatin. Different molecular imprint routes were used to prepare these biomimetic sensors including solution polymerization, thermal polymerization, and electropolymerization. The unique characteristics of each MIP-modified SPE are discussed and the comparison among the findings of the papers is critically reviewed.

• Applied Biological Chemistry
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• 제26권4호
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• pp.239-247
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• 1983

토양처리(土壤處理) 살충제(殺蟲劑)인 parathion을 토양수분조건(土壤水分條件)과 약제(藥劑)의 농도(濃度), 온도(溫度), pH, 및 토양미생물(土壤微生物)의 영향에 의해 분해(分解)되는 양상(樣相) 과 토양(土壤) 효소활성(酵素活性)에 미치는 영향을 실험(實驗)한 결과(結果)는 다음과 같다. 침수답토양(?水畓土壤) 조건(條件)이 비침수(非浸水) 상태(狀態)보다, 전토양(田土壤)에서는 수분(水分)이 많은 처리구(處理區)에서 분해(分解)가 빨랐으며 답(沓)전토양(田土壤) 모두 저온구(低溫區)에 비해 고온구(高溫區)에서, 저농도(低濃度)보다 고농도(高濃度) 처리구에서, 토양(土壤) pH 수준이 높은구에서 분해율(分解率)이 증가하였고, 토양(土壤) pH 수준이 높은구에서 분해율(分解律)이 증가하였고, 포도당 첨가는 분해를 증대시켰는데 살균토양(殺菌土壤)은 비살균토양(非殺菌土壤)에서 보다 완만한 분해(分解)를 나타냈다. 상기(上記) 몇가지 인자(因子)들의 영향하에서 답토양(沓土壤)이 전토양(田土壤)보다 분해(分解)가 빨리 일어났다. 시기별로 채취한 시료에서 확인(確因)된 분리산물(分利産物)로는 paraoxon, aminoparathion, p-nitrophenol과 p-aminophenol 등이 논.밭 토양(土壤)에서 똑 같았다. 토양효소(土壤酵素) acid phosphatase의 활성(活性)은 처리농도(處理濃度)가 높은 구에서 밭 토양(土壤)은 비침수상태(非浸水狀態), 논 토양(土壤)은 침수조건(浸水條件)에서, 토양(土壤) pH가 높은 수준일 수록 활성(活性)이 더욱 저하(低下)되었고, 살균토양(殺菌土壤)은 활성(活性)이 거의 없었고 포도당 첨가구엔 크게 증가(增加)하는 경향이었다. Urease와 dehydrogenase의 활성(活性)은 처리농도(處理濃度)가 높을수록 더욱 저하(低下)되었으며, 모든 토양효소(土壤酵素)는 밭 토양(土壤)이 논 토양(土壤)보다 활성(活性)이 전(全) 처리구(處理區)에서 낮았다.

• 한국응용곤충학회지
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• 제37권2호
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• pp.179-185
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• 1998

파밤나방(Spodoptera exigua (H bner))의 생리적 요인이 에스테라제 변이에 미치는 영향을 파악하고자 전기영동을 이용한 동위효소 분석이 이루워졌다. 또한 각 동위효소의 화학적 특성을 파악하고자 기질 및 억제제에 따라 반응성을 분석하였다. 총 28개의 에스테라제 동위효소들이 10%비변성 전기영동에서 분리되었다. 이들 동위효소들은 양극으로 이동거리 증가에 따라 E1에서 E28까지 명명되었다. 파밤나방의 발육단계에 따라 에스테라제 동위효소는 변이를 보였다. 유충과 용이 성충에 비해 많은 수의 에스테라제 동위효소를 보였고, 알이 가장 적은 수를 나타냈다. 특히 E1과 E2는 1령충에서 특이하게 발현되는 도우이효소들이 있다. 서로 다른 조직간에도 에스테라제 동위효소 변이를 보였다. 혈림프와 지방체에 비해 표피와 소화관 조직에서 더많은 수의 에스테라제가 발현됐다. E1-E6 동위효소는 표피조직에 E10, E11, E25, E26 및 E27은 소화관조직에, 그리고 E18은 혈림프에 각각 특이한 에스테라제 동위효소들이었다. 조사된 haphtyl ester계통의 에스테라제 기질들 중에서 $\alpha$-naphty1 propionate가 모든 에스테라제 동위효소에서 가장 높은 반응성을 보였다. 이들 동위효소는 에스테라제 억제제(exerine, dichloroves, moncrotophs 및 paraox-on)에 대한 반응에 따라 E10과 E24는 콜린에스테라제, E4, E9,E17, E19, E21 및 E23은 아릴에스테라제 및 나머지 20종은 카르복실에스테라제로 각각 판명되었다.