• 한국환경농학회지
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• 제21권2호
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• pp.149-155
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• 2002

상추의 생산단계에서의 잔류허용기준 설정과 최종 소비단계에서의 안전성 평가자료로 활용하기 위하여 지금까지 상추수확물에서의 잔류수준과 검출빈도가 높은 것으로 알려진 살충제 chlorpyrifos 및 살균제 procymidone의 포장상태에서의 생물학적 반감기, 보관상태에 따른 잔류량 변화 그리고 세척형태에 따른 제거율을 조사하였다. 시설재배포장에서 상추중두 약제의 살포농도별 생물학적 반감기를 측정한 결과 기준량 살포의 경우 chlorpyrifos 1.2일 및 procymidone 1.3일 배량살포의 경우에는 chlorpyrifos 1.5일 및 procymidone 2.6일로 나타났다. 유통과정중에서 일어날 수 있는 두 가지 농약의 잔류량 변화를 알아보기 위해서 실온(20$^{\circ}C$) 및 냉장(4$^{\circ}C$) 상태로 보관하면서 두 약제의 잔류량 변화를 조사한 결과 반감기는 실온저장시 chlorpyrifos 3.8일, procymidone 20.9일이었고, 냉장저장시에는 chlorpyrifos 12.4일 procymidone 20.9일로 나타나 두 약제 모두 실온저장보다 냉장저장시 잔류량의 감소가 훨씬 느린 것으로 나타났다. 세척방법에 의한 잔류농약의 감소량을 조사한 결과 세제 사용시의 평균 제거율은 chlorpyrifos 48.3%, procymidone 52.6%로 나타났고, 물 사용 시에는 chlorpyrifos 31.3%, procymidone 38.1%로 나타났다.

• 분석과학
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• 제26권3호
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• pp.174-181
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• 2013

Pyrifluquinazon은 quinazoline 계통의 살충제로 진딧물, 흰파리 등 해충에 대해 음식섭취를 조절하는 신경계 또는 내분비계에 작용하여 섭식행동을 제어하고 또한 식물조직에 추가적 손상을 방지, 식물체 바이러스 확산을 막는 역할을 한다. 국내에는 2012년 사과와 배에 신규 사용등록되어 식품의약품안전처에서 잔류허용기준을 설정하였다. 본 농약은 분자량이 464.3으로 큰 편이며, 증기압이 낮아 분석을 위한 기기로 HPLC-UVD를 선택하여 잔류허용기준 준수여부 확인을 위한 시헙법을 확립하였다. 추출용매는 간섭물질의 추출이 비교적 적은 acetonitrile을 사용하였으며, pyrifluquinazon의 Log $P_{ow}$값이 3.12로 극성에 가까운 물리화학적 특성을 감안하여 액-액 분배를 위한 용매로 dichloromethane을 사용하였다. 간섭물질 제거를 위한 clean-up과정에서는 silica 카트리지를 사용하였고, acetone으로 용출하여 최적의 정제조건을 확립하였다. 분석 결과 회수율은 70~120%로 나타났으며, 분석오차는 10% 미만, 실험실간 편차 ($RSD_R$(%)) > 0.01 mg/kg, ${\leq}$0.1 mg/kg 범위에서 3.40~15.4%로 코덱스 가이드라인 기준에 적합함을 확인 하였다. 또한 본 시험법의 재현성 및 선택성을 추가로 확보할 수 있도록 LC-MS를 통한 정성시험법을 추가로 확립하였다. 본 시험법은 신규 등록된 pyrifluquinazon 분석을 위한 신속 정확한 공정 시험법으로 식품공전에 등재되어 활용되고 있다.

• 한국식품위생안전성학회지
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• 제29권4호
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• pp.292-298
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• 2014

차 중에 있는 살균제 tridemorph의 잔류량을 검사하기 위해 LC-ESI-MS/MS를 이용한 정확하고 감도가 좋은 분석방법을 개발하였다. Tridemorph 잔류물은 샘플을 수화한 후 acetonitrile로 추출하고, NaCl을 이용한 액-액 분배, $NH_2$ 카트리지 정제를 거쳐 기기분석을 수행하였다. 직선성은 $0.02{\sim}1.0{\mu}gmL^{-1}$ 범위에서 상관계수($r^2$) 0.9999로 높은 직선성을 보였다. 0.02와 $0.05mgkg^{-1}$ 처리수준으로 회수율을 실험한 결과는 75.0~84.7% 이었으며, 상대표준편차는 10% 미만이었다. 분석방법의 검출한계와 정량한계는 각각 0.01와 $0.02mgL^{-1}$ 이었다. 이러한 결과들을 통해 확립된 분석법은 차 중 tridemorph의 잔류량 분석에 적합함을 확인할 수 있었다.

• BMB Reports
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• 제32권6호
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• pp.547-553
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• 1999

Aminoacyl-tRNA synthetases are essential enzymes catalyzing the attachment of specific amino acids to cognate tRNAs. In the present work, the substrate analogue L-methionine hydroxamate was used to identify functional residues located in the active site of the E. coli methionyl-tRNA synthetase (MetRS). This compound inhibited bacteria, yeast, and human MetRS activities to a similar degree, suggesting a conserved active site structure and mechanism between MetRSs of different phylogenetic domains. Mutants of the E. coli MetRS resistant to methionine hydroxamate were also isolated. These mutants contained a substitution either at T10, Y15, or Y94. These residues are highly conserved among the different MetRSs and the mutants showed decreased aminoacylation activity, suggesting their functional and structural significances. The putative roles of these residues are discussed on a structural basis.

• 미생물학회지
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• 제29권2호
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• pp.136-142
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• 1991

The selection of ethanol-tolerant strains was applied to enrichment culture of YPD broth medium containing various concentrations of ethanol. Isolates were identified to be Saccharomyces cerevisiae, the others as S. dairensis, S. exiguus, S. telluris, Saccharomycodes ludwigii, Schwanniomyces occidentalis var. occidentalis and Zygosaccharomyces florentinus. Among isolates S. cerevisiae YO-1 was screened as having the highest ethanol tolerance and produced 18% (v/v) ethanol after 4 days fermentation. The change of fatty-acyl residues represents that a progressive decrease in fatty-acyl unsaturation and a proportional increase in saturation in phospholipids of yeast cells during fermentation affected the yeast viability. Supplementation ethanol to the cultures led to an increase of unsaturated fatty-acyl residues, especially $C_{16}$ or $C_{18}$ residues, along with a decrease in the proportion of saturated residues in cellular phospholipids. Increasing the amount of soy flour led to an increase in the maximum number of viable yeast cells and ethanol production. It was possible in 4 days to reach 21% (v/v) ethanol by adding 4% soy flour as source of unsaturated fatty-acyl residues to the fermentation medium. Soy flour not only increased yeast population but also enhanced the physiological properties of yeast cells to be ethanol tolerant in the anaerobic culture.

• The Korean Journal of Physiology and Pharmacology
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• 제22권1호
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• pp.91-99
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• 2018

Protein phosphatase 1 (PP1) is involved in various signal transduction mechanisms as an extensive regulator. The PP1 catalytic subunit (PP1c) recognizes and binds to PP1-binding consensus residues (FxxR/KxR/K) in NBCe1-B. Consequently, we focused on identifying the function of the PP1-binding consensus residue, $^{922}FMDRLK^{927}$, in NBCe1-B. Using site-directed mutagenesis and co-immunoprecipitation assays, we revealed that in cases where the residues were substituted (F922A, R925A, and K927A) or deleted (deletion of amino acids 922-927), NBCe1-B mutants inhibited PP1 binding to NBCe1-B. Additionally, by recording the intracellular pH, we found that PP1-binding consensus residues in NBCe1-B were not only critical for NBCe1-B activity, but also relevant to its surface expression level. Therefore, we reported that NBCe1-B, as a substrate of PP1, contains these residues in the C-terminal region and that the direct interaction between NBCe1-B and PP1 is functionally critical in controlling the regulation of the ${HCO_3}^-$ transport. These results suggested that like IRBIT, PP1 was another novel regulator of ${HCO_3}^-$ secretion in several types of epithelia.

• 한국동물위생학회지
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• 제15권2호
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• pp.93-100
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• 1992

The purpose of the present survey was to evaluate the antibiotic residues in meats and internal organs such as muscle, liver, heart, kidney and spleen of cattle (n=59) and pigs (n=115). The EEC-4-plate-method were employed. The results were obtained as follows ; 1. In BS 6.0, BS 7.2 and BS 8.0 used as media to detect antibiotic residues, the zone($M{\pm}SD,$ cm) of bacterial growth inhibition was narrow($1.40{\pm}0$) in meats, whereas the zone was wide($1.69{\pm}0.25-1.88{\pm}0.23$ and $1.58{\pm}0.18-1.86{\pm}0.15$ in cattle and pigs, respectively) in internal organs. But in SL 8.0, it was difficult to detect the zones ($0-1.40{\pm}0$) of both meats and internal organs. 2. Residues of antibiotic in beef and pork were rarely detected in BS 6.0, BS 7.2 and BS 8.0 (range 1.7-11.9% and 2.6-4.3%, respectively), whereas residual percentages of internal organs were relatively higher(range 69.5-96.6% and 43.5-84.3%, respectively). But in SL 8.0, it was not detected in both beef or pork, whereas they were 0-13.6% and 0-4.3% in interanal organs.

• Journal of Dairy Science and Biotechnology
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• 제31권1호
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• pp.59-65
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• 2013

Antibiotic residues are undesirable in milk and milk products for a number of reasons. In particular, they can have harmful effects on public health and harm to the manufacturer of the cultured milk products, e.g. MRSA etc. Although government regulatory agencies and the dairy industry have been successful in decreasing the presence of high concentrations of antibiotic residues, violations still occur and lead to contaminated products. As a result, several rapid and reliable methods for the detection of antibiotic residues have been developed, including microbiological and instrumental analysis methods. The conventional methods are time consuming, but recent improvements have allowed for better detection time, sensitivity, and accuracy. An example of an advanced detection instrument is the biosensor, which has several applications in food and environmental science, e.g. food-born pathogen detection, antimicrobial residues etc. In the present review, the recent trends in the methods used to test for antibiotic residues in milk and dairy products, as well as their specific applications, have been discussed.

• Asian-Australasian Journal of Animal Sciences
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• 제17권7호
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• pp.967-972
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• 2004

Four Holstein$\times$Indigenous cows with ruminal canulas were used in a 4$\times$4 Latin square design with 28 d periods to determine the effect of replacing nonforage fiber source (NFFS) from cassava residues for non-fiber carbohydrates (NFC) on ruminal fermentation characteristics and milk production. Dietary treatments contained 17% forage neutral detergent fiber (FNDF) from corn silage and 0, 3, 6 and 9% nonforage NDF from cassava residues and 11% nonforage NDF from other NFFS, so that levels of nonforage NDF were 11, 14, 17 and 20% dry matter (DM). Intakes of DM and net energy for lactation, average daily gain and milk fat percentage were not different (p>0.05). Ruminal pH, ammonia concentrations, acetate to propionate ratios, 24 h in sacco fiber digestibility significantly increased with increasing contents of nonforage NDF from cassava residues. Concentrations of VFA, urinary excretion of purine derivatives, milk protein percentage, production of milk and 4% FCM significantly decreased. These results suggest that NFC in diets is one of the limiting factors affecting productivity of dairy cows in the tropics and thus NFFS is better used as partial replacements for FNDF.

• 한국동물위생학회지
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• 제28권3호
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• pp.285-294
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• 2005

This study was conducted to investigate the extraction method for the determination of organochlorine, organophosphorus and synthetic pyrethroid pesticide residues in beef fat by gas chromatography-mass selective detector(GC-MSD). Twenty one pesticide residues in fat were determined using a simple and rapid procedure based on solid- phase extraction(SPE) clean-up cartridges with octadecyl $(C_{18})-bonded$ porous silica, florisil, $10\%$ deactivated florisil. a tandem $C_{18}$ and florisil and a tandem $C_{18}$ and $10\%$ deactivated florisil. Solvent-solvent extraction using acetonitrile was not satisfied to eliminate fat interference for pesticide residue analysis by GC-MSD, and the recoveries of the method in fat ranged from 16.2 to $57.3\%$ except DDT$(83.2\%)$. The recoveries of SPE methods using a tandem $C_{18}$ and Florisil was $59.6\~123.8\%$ except fenitrothion $(135.2\%)$. the SPE method was verified the satisfactory performance of pre-treatment for pesticide residues analysis in fat by GC-MSD. The efficiency of florisil deactivated with $10\%$ water has been not proved significantly on recoveries of pesticide residues in fat.