• 생태와환경
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• 제43권4호
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• pp.453-458
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• 2010

DOC (Dissolved Organic Carbon) is an operational terminology for organic carbon molecules dissolved in natural waters. DOC has been studied by ecologists extensively, because it plays a key role in various ecological functions such as substrates for secondary production and the carbon cycle. DOC also represents a substrate for microbial growth within potable water distribution systems, and can react with disinfectants (e.g., chloride) to form harmful disinfection by-products. In addition, residual DOC may carry with it organically bound toxic heavy metals. DOC in aquatic ecosystems may ultimately be transported to the oceans, or released back to the atmosphere by heterotrophic respiration, which can accelerate global climate change. There is evidence that DOC concentrations in aquatic ecosystems are increasing in many regions of the world including Europe, North America, and even in Korea. Land use changes, elevated temperature, elevated $CO_2$, recovery from acidification, and nitrogen deposition have been proposed as mechanisms for the trend. However, the key driving mechanism is yet to be conclusively determined. We propose that more extensive and longer-term observations, research of chemical properties of DOC, impacts of elevated DOC on environmental issues and interdisciplinary approaches are warranted as future studies to fill the gaps in our knowledge about DOC dynamics.

• Journal of Applied Biological Chemistry
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• 제59권2호
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• pp.165-169
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• 2016

The quantitative analytical method for the bioactive substance, 3-cyano-4-methoxy-N-methyl-2-pyridone (ricinine) and an index compound, ricinoleic acid in castor plant (Ricinus communis) extract or oil was developed. For the determination of a pyridone alkaloid compound, ricinine, successive cartridge cleanup method combined with ultra-performance liquid chromatography was set up with $ENVI-Carb^{TM}$ (0.5 g) and $C_{18}$ SPE cartridges. Accuracy and precision were evaluated through fortification studies of one biopesticide (PE) at 10 and $100mg\;kg^{-1}$. Mean recoveries of ricinine were 98.7 and 96.0 % associated with less than 10 % RSD, respectively. For the determination of ricinoleic acid in castor extract and oil, saponification and methylation were optimized using gas chromatography-time of flight mass spectrometry. Recovery was more than 84.8 % associated with 6.2 % RSD after derivatization procedure. Both methodologies developed were applied to analyze real samples including three castor oil products and six commercially available biopesticides containing R. communis, collected at Korean market. The contents of ricinine and ricinoleic acid in most commercial biopesticides were less than the oil or extract contents indicated by label.

• Journal of Microbiology and Biotechnology
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• 제18권7호
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• pp.1317-1325
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• 2008

Viral safety is an important prerequisite for clinical preparations of plasma-derived pharmaceuticals. One potential way to increase the safety of therapeutic biological products is the use of a virus-retentive filter. In order to increase the viral safety of human antihemophilic factor IX, particularly in regard to non-enveloped viruses, a virus removal process using a polyvinylidene fluoride membrane filter (Viresolve NFP) has been optimized. The most critical factor affecting the filtration efficiency was operating pH and the optimum pH was 6 or 7. Flow rate increased with increasing operating pressure and temperature. Recovery yield in the optimized production-scale process was 96%. No substantial changes were observed in the physical and biochemical characteristics of the filtered factor IX in comparison with those before filtration. A 47-mm disk membrane filter was used to simulate the process performance of the production-scale cartridges and to test if it could remove several experimental model viruses for human pathogenic viruses, including human hepatitis A virus (HAV), porcine parvovirus (PPV), murine encephalomyocarditis virus (EMCV), human immunodeficiency virus type 1 (HIV), bovine viral diarrhea virus (BVDV), and bovine herpes virus (BHV). Non-enveloped viruses (HAV, PPV, and EMCV) as well as enveloped viruses (HIV, BVDV, and BHV) were completely removed during filtration. The log reduction factors achieved were $\geq$6.12 for HAV, $\geq$4.28 for PPV, $\geq$5.33 for EMCV, $\geq$5.51 for HIV, $\geq$5.17 for BVDV, and $\geq$5.75 for BHV. These results indicate that the virus filtration process successfully improved the viral safety of factor IX.

• KSBB Journal
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• 제21권2호
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• pp.144-150
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• 2006

본 연구는 메타게놈 유전자 특성과 E. coli에서 정상적으로 발현되는 유전자 특성을 생물정보학 기법으로 비교 분석하고 그 결과를 메타게놈 선별 연구에 활용하고자 하는데 그 목적을 두었다. 이를 위하여 메타게놈 유래의 URF 와 숙주세포로 이용되는 E. coli이 ORF에 대한 염기구조, 발현되는 단백질의 크기 및 분자량, 아미노산의 구성 및 코돈사용은 물론 전사와 번역에 관여하는 프로모터 부위와 리보솜 결합부위의 보존서열 특성을 비교 분석하였다. 메타게놈과 E. coli가 합성하는 단백질의 크기와 분자량은 매우 비슷한 경향을 보였으나, 아미노산의 조성비, G+C 함량 및 코돈사용에서는 매우 다른 경향을 나타내었다. 특히 전사와 번역에 직접적으로 관여하는 프로모터와 RBS 영역에서의 DNA 보존서열이 상당부분 부합되지 않아 E. coli에서 메타게놈의 발현율이 현저히 낮을 것으로 예측할 수 있었다. RBS와 같이 유전자 발현에 필수적인 조절인자가 메타게놈과 E. coli에서 큰 차이를 나타내는 문제점은 메타게놈으로부터 유용한 유전자원을 탐색하는 연구에서 심도있게 개선하여야 할 사항이다. 부분적으로는 라이브러리 구축에 사용되는 벡터 및 숙주의 개량을 통하여 위의 문제를 극복할 수도 있을 것이다.

• 분석과학
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• 제36권1호
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• pp.22-31
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• 2023

As the use of e-liquid cigarettes is rapidly increasing worldwide, it multiplies the potential risk undisclosed to the health of non- and smokers. To reduce the hazard, each country has its own set of regulations for controlling e-liquids. In Korea, the narrow definition of tobacco makes it difficult and have been steadily occurring tax evasion exploiting the difference in natural and artificial nicotine. Therefore, it is very important to distinguish source of nicotine for their regulation. To find biochemical discriminant markers, this study established analysis methods based on high-performance liquid chromatography coupled with diode array detector (HPLC-DAD) and high-performance liquid chromatography coupled with triple Quadrupole mass spectrometry (HPLC-MS/MS) for nicotine enantiomers and tobacco alkaloids targeted using the difference in pathways of nicotine biosynthesis and chemical synthesis. The method was validated by experimenting linearity (R² > 0.999), recovery (80.99-108.41 %), accuracy (94.11-109.73 %) and precision (0.04-8.27 %). Then, the results for discrimination of the nicotine obtained from analysis of 65 commercial e-liquid products available in Korean market was evaluated. The method successfully applied to the e-liquids and one sample labelled 'synthetic nicotine' for tax exemption was found to contain a natural nicotine product. This method can be used to determine whether an e-liquid product uses natural or artificial nicotine and monitor non-taxable e-liquid products. The method is more scientific than the existing one, which relies only on field evidence.

• 한국환경농학회지
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• 제31권1호
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• pp.45-51
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• 2012

본 연구는 단감 재배 중 사용되는 살균제인 pyrimethanil과 trifloxystrobin의 생산단계 잔류허용기준 설정을 통하여 안전한 단감 생산에 기여하고자 수행되었다. 먼저 pyrimethanil과 trifloxystrobin을 살포하고, 살포 후 0, 1, 2, 3, 5, 7, 10, 12, 15, 18일에 단감 시료를 채취하여 각각의 농약을 분석하고 생물학적 반감기를 산출한 다음 생산단계 잔류허용기준(PHRL; Pre-Harvest Residue Limit)을 설정하였다. 단감 중 pyrimethanil과 trifloxystrobin은 Acetonitrile을 이용하여 추출하고 $NH_2$ cartridge와 PSA를 이용하여 정제하여 HPLC/DAD를 이용하여 분석하였다. 두 농약에서 검출한계는 모두 0.01 mg/kg이었다. Pyrimethanil의 회수율은 0.1과 0.5 mg/kg 두 수준에서 각각 $81{\pm}1.62%$, $98{\pm}1.58%$ 이었으며, trifloxystrobin의 회수율은 0.1과 0.5 mg/kg 두 수준에서 각각 $91{\pm}2.94%$, $98{\pm}1.25%$이었다. 단감에서 pyrimethanil의 생물학적 반감기는 기준량 살포 시 15.6일, 배량 살포 시 11.6일이었고, trifloxystrobin의 생물학적 반감기는 기준량 살포 시 10.4일, 배량 살포 시 10.3일이었다. 잔류회귀 감소식을 이용한 생산단계 잔류허용기준은 pyrimethanil과 trifloxystrobin은 각각 수확 10일 전 2.69 mg/kg과 0.83 mg/kg으로 제안하였다.

• 농약과학회지
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• 제15권1호
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• pp.8-14
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• 2011

취나물 재배 중 methoxyfenozide 및 novaluron을 살포하고, 0일부터 10일까지 총 7회 시료를 채취하였다. methoxyfenozide와 novaluron온 methanol로 추출한 후 dichloromethane으로 분배하여 HPLC로 분석하였다. 분석결과 $0.4\;mg{\cdot}kg^{-1}$과 $2\;mg{\cdot}kg^{-1}$수준에서 methoxyfenozide의 평균회수율은 $102.5{\pm}3.03%$ 및 $84.4{\pm}2.82%$이었고, novaluron은 $88.7{\pm}2.32%$ 및 $90.6{\pm}4.50%$이었다. 재배기간 중 methoxyfenozide의 기준량 잔류반감기는 3.99일이고 novaluron은 3.16일 이었다. 증제량에 따른 희석효과를 배제한 잔류감소곡선은 novaluron의 경우 잔류량 감소의 주요인으로 작용하지 않았다. Methoxyfezide와 novaluron을 안전사용기준에 따라 처리시, 최종잔류농도는 MRL이하로 떨어질 것으로 계산된다.

• Natural Product Sciences
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• 제21권1호
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• pp.30-33
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• 2015

Anthocyanins are water soluble plant pigments which are responsible for the blue, red, pink, violet colors in several plant organs such as flowers, fruits, leaves and roots. In recent years, anthocyanin-rich foods have been favored as dietary supplements and health care products due to diverse biological activities of anthocyanins including antioxidant, anti-allergic, anti-diabetic, anti-microbial, anti-cancer and preventing cardiovascular disease. High-performance countercurrent chromatography (HPCCC) coupled with reversed-phase medium pressure liquid chromatography (RP MPLC) method was applied for the rapid and efficient isolation of cyanidin 3-glucoside (C3G) and peonidin 3-glucoside (P3G) from black rice (Oryza sativa L., Poaceae). The crude black rice extract (500 mg) was subjected to HPCCC using two-phase solvent system composed of tert-butyl methyl ether/n-butanol/ acetonitrile/0.01% trifluoroacetic acid (TBME/B/A/0.01% TFA, 1 : 3 : 1 : 5, v/v, flow rate - 4.5 mL/min, reversed phase mode) to give enriched anthocyanin extract (37.4 mg), and enriched anthocyanin extract was sequentially chromatographed on RP-MPLC to yield C3G (16.5 mg) and P3G (8.7 mg). The recovery rate and purity of isolated C3G were 76.0% and 98.2%, respectively, and those of P3G were 58.3% and 96.3%, respectively. The present study indicates that HPCCC coupled with RP-MPLC method is more rapid and efficient than multi-step conventional column chromatography for the separation of anthocyanins.

• 한국축산식품학회지
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• 제35권4호
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• pp.459-465
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• 2015

Bovine milk provides essential nutrients, including immunologically important molecules, as the primary source of nutrition to newborns. Recent studies showed that RNAs from bovine milk contain immune-related microRNAs (miRNA) that regulate various immune systems. To evaluate the biological and immunological activity of miRNAs from milk products, isolation methods need to be established. Six methods for extracting total RNAs from bovine colostrums were adopted to evaluate the isolating efficiency and expression of miRNAs. Total RNA from milk was presented in formulation of small RNAs, rather than ribosomal RNAs. Column-combined phenol isolating methods showed high recovery of total RNAs, especially the commercial columns for biofluid samples, which demonstrated outstanding efficiency for recovering miRNAs. We also evaluated the quantity of five immune-related miRNAs (miR-93, miR-106a, miR-155, miR-181a, miR-451) in milk processed by temperature treatments including low temperature for long time (LTLT, 63℃ for 30 min)-, high temperature for short time (HTST, 75℃ for 15 s)-, and ultra heat treatment (UHT, 120-130℃ for 0.5-4 s). All targeted miRNAs had significantly reduced levels in processed milks compared to colostrum and raw mature milk. Interestingly, the amount of immune-related miRNAs from HTST milk was more resistant than those of LTLT and UHT milks. Our present study examined defined methods of RNA isolation and quantification of immune-specific miRNAs from small volumes of milk for use in further analysis.

• 한국환경농학회지
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• 제39권4호
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• pp.305-311
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• 2020

BACKGROUND: The healthy food trend has encouraged the consumption of natural products, including berries. This trend is expected to increase the strawberry consumption. There has been a concern about the exposure of pesticides approved for use on strawberry. In this study, the dissipation patterns of systemic and non-systemic pesticides were evaluated in strawberry under plastic-covered greenhouse conditions. METHODS AND RESULTS: Cyflumetofen and dimethomorph were applied on strawberry in the critical GAP (Good Agricultural Practices). Strawberries were harvested at 0, 1, 2, 3, 5, 7 and 10 days after final application of the pesticides. The analyses of the residual pesticides were performed by HPLC-DAD with C18 column. The limits of quantitation (LOQ) of cyflumetofen and dimethomorph were 0.04 and 0.02 mg/kg, respectively. The recovery of cyflumetofen and dimethomorph were 88.1 ~ 103.3% and 79.0 ~ 110.2% for the spiked two levels (LOQ and 10LOQ), respectively. The biological half-lives of cyflumetofen and dimethomorph werer 7.5 and 8.9 days, respectively. The dissipation rates in strawberry were calculated by the statistics method at a 95% confidence level. The distribution showed that pesticides with low log Pow were indicated by the decreased dissipation rate and pesticides with similar log Pow and low solubility also showed the decreased dissipation rate. CONCLUSION: The residues of cyflumetofen and dimethomorph in strawberry at time 0 after the final application were below the established MRL in Korea. The dissipation behavior of systemic and non-systemic pesticides in strawberry is affected by their log Pow and water solubility values.