• The Korean Journal of Pesticide Science
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• v.12 no.1
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• pp.24-33
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• 2008

In this study, the mobility of seven pesticides from soil in different slopes was investigated by simulated rainfall under field conditions. Simulated rainfall subjected to $22\;mm\;hr^{-1}$ was treated using rainfall simulator after 12 hr of pesticide treatment. Amounts of the pesticides were measured in run-off water samples. The soil samples collected before and after rainfall from upper, middle and lower parts and three different depths of sloped-plot were also analyzed. At result, the order of the amount of pesticide residues was $0{\sim}15$ > $15{\sim}30$ > $30{\sim}45\;cm$ of soil depth and no pattern was shown in upper, middle and lower, and different slopes in soil samples. all pesticides from the run-off water samples collected from soils were detected maximum 96% within 60 minutes after first collection except carbendazim and cypermethrin which have the lowest water solubilities. These results revealed that mobility of pesticides can be dependant mainly on soil textures and physicochemical properties of pesticides. Therefore, it can be suggested that selection of pesticides should be considered for properties of pesticide in the alpine and sloped-land.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.734-740
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• 2010

Overuse of veterinary antibiotics threats public health and surrounding environment due to the occurrence of antibiotic resistant bacteria. The objective of this study was to evaluate the antibiotic's concentrations of tetracycline (TC), chlortetracycline (CTC), and oxytetracycline (OTC) in a tetracycline group (TCs), sulfamethazine (SMT), sulfamethoxazole (SMX), and sulfathiazole (STZ) in a sulfonamide group, lasalocid (LSL), monensin (MNS), and salinomycin (SLM) in a ionophore (IPs), and tylosin (TYL) in a macrolide (MLs) group from soil, water, and sediment samples adjacent to a cattle manure composting facility. For all samples of soil, water, and sediment, the highest concentrations were detected in TCs among the tested antibiotics because of its higher annual consumption in veterinary farms, Korea and its higher cohesiveness with divalent or trivalent cations in soil. Moreover, the concentrations of residual antibiotics in September were generally higher than in June because of heavier rainfall in June. We suggest that continual monitoring and developing guideline of antibiotics are needed to control residual antibiotics in the environment.

• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.289-298
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• 2020

As part of the research program "2018 Rapid screening and identification of freshwater microorganisms using MALDI-TOF/MS library" freshwater samples were collected from a branch of the Nakdong River. Almost 300 antibiotic-resistant bacterial strains were isolated from freshwater samples and subsequently identified by 16S rRNA gene sequencing. Seventeen strains among the isolates shared high 16S rRNA gene sequence similarity (>99.0%) with known species that were not previously recorded in Korea, and each of the isolates also formed a robust phylogenetic clade with the closest species. These species were phylogenetically diverse, belonging to four phyla, seven classes, 10 orders, and 13 genera. At the genus and class level, the previously unrecorded species belonged to Rhodovarius, Xanthobacter, and Shinella of the class Alphaproteobacteria; Ottowia, Simplicispira, and Zoogloea of Betaproteobacteria; Pseudomonas, Acinetobacter, and Shewanella of Gammaproteobacteria; Arcobacter of Epsilonproteobacteria; Sphingobacterium of Sphingobacteriia; Trichococcus of Bacilli; and Leucobacter of Actinobacteria. The previously unrecorded species were further characterized by examining their gram-staining, colony and cell morphology, biochemical properties, and phylogenetic position.

• Applied Biological Chemistry
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• v.41 no.8
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• pp.595-599
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• 1998

An analytical method was developed to determine tricyclazole residues in rice grain, straw, and soil using high-performance liquid chromatography (HPLC) with ultraviolet absorption detection. Tricyclazole was extracted with methanol from moist rice grain, straw, and soil samples. n-Hexane washing was employed to remove nonpolar co-extractives during liquid-liquid partition. Tricyclazole was then extracted with dichloromethane from alkaline aqueous phase, while acidic interferences remained in the phase. Dichloromethane extract was further purified by silica gel column chromatography prior to HPLC determination. Reverse-phase HPLC using an octadecylsilyl column was successfully applied to separate and quantitate the tricyclazole residue in sample extracts monitored at ${\lambda}_{max}$ 225nm. Recoveries from fortified samples averaged $95.5{\pm}3.0%\;(n=6),\;87.5{\pm}20.%\;(n=6),\;and\;84.3{\pm}2.8%$ (n=12) for rice grain, straw, and soil, respectively. Detection limit of the method was 0.02 mg/kg for rice grain and soil samples while 0.05 mg/kg for rice straw samples. The proposed method was reproducible and sensitive enough to evaluate the safety of tricyclazole residues in rice grain, straw, and soil.

• Applied Biological Chemistry
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• v.51 no.4
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• pp.251-257
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• 2008

Different types of milk products, such as kwacha golla, mawa, cheese, curd, and chocolate are popular in Bangladesh. However, the microbiological safety of these products is poorly understood. This study was performed to assess the microbiological quality of kwacha golla, a local milk product. Kwacha golla samples were collected from ten different areas of Rajshahi and Kushtia regions, and the quality of the each sample was assessed using various parameters including standard plate count, total coliform, fecal coliform, total fungi, and spore-forming bacteria, as well as food-borne microorganisms. Out of 300 samples, total coliform was detected at 56.66% (n= 300), exceeding the minimum allowable limit of 36.66%. Similarly, experiments were carried out with fungi and food-borne pathogens including Escherichia coli, Listeria monocytogenes, Salmonella sp., and Staphylococcus aureus. Results revealed 85.33, 53, and 49.33% of the samples were contaminated by fungi, E. coli, and L. monocytogenes, respectively. However, all samples showed no contaminations of Salmonella sp. and Staphylococcus sp. Therefore, this study could be helpful to the people of Bangladesh by providing information on the possibility of a major health problem caused by the consumption of kwacha golla.

• Mass Spectrometry Letters
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• v.4 no.2
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• pp.25-29
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• 2013

Proteomics for biomarker validation needs high throughput instrumentation to analyze huge set of clinical samples for quantitative and reproducible analysis at a minimum time without manual experimental errors. Sample preparation, a vital step in proteomics plays a major role in identification and quantification of proteins from biological samples. Tryptic digestion a major check point in sample preparation for mass spectrometry based proteomics needs to be more accurate with rapid processing time. The present study focuses on establishing a high throughput automated online system for proteolytic digestion and desalting of proteins from biological samples quantitatively and qualitatively in a reproducible manner. The present study compares online protein digestion and desalting of BSA with conventional off-line (in-solution) method and validated for real time sample for reproducibility. Proteins were identified using SEQUEST data base search engine and the data were quantified using IDEALQ software. The present study shows that the online system capable of handling high throughput samples in 96 well formats carries out protein digestion and peptide desalting efficiently in a reproducible and quantitative manner. Label free quantification showed clear increase of peptide quantities with increase in concentration with much linearity compared to off line method. Hence we would like to suggest that inclusion of this online system in proteomic pipeline will be effective in quantification of proteins in comparative proteomics were the quantification is really very crucial.

• Applied Biological Chemistry
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• v.32 no.3
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• pp.203-208
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• 1989

Eight samples of Korean two-rowed barley, 9 samples of North American barley and 3 samples of Korean six-rowed barley were analysed for 1,000 kernel weight, steeping time, germinative capacity, and protein content. The barley samples were malted with the same malting schedule and analyzed for malting loss, protein content, soluble protein, percent extract, wort viscosity, and diastatic power. The American barleys were higher in germinative capacity, percent extract and diastatic power than the Korean two-rowed barleys. The protein content ranged from 11.8 to 14.2% for the North American barleys and 9.7 to 15.5% for Korean barleys. The three Korean six-rowed barleys were lower in germinative capacity, percent extract and diastatic power, but were higher in wort viscosity than the Korean two-rowed barleys.

• Analytical Science and Technology
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• v.32 no.3
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• pp.88-95
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• 2019

This study was conducted to establish the analytical method for the determination of cyanide in blood, urine, lung and skin tissues in rats. In order to detect or quantify the sodium cyanide in above biological matrixes, it was derivatized to Pentafluorobenzyl cyanide (PFB-CN) using pentafluorobenzyl bromide (PFB-Br) and then reaction substance was analyzed using gas chromatography mass spectrometer (GC/MS)-SIM (selected ion monitoring) mode. The analytical method for cyanide determination was validated with respect to parameters such as selectivity, system suitability, linearity, accuracy and precision. No interference peak was observed for the determination of cyanide in blank samples, zero samples and lower limit of quantification (LLOQ) samples. The lowest limit detection (LOD) for cyanide was $10{\mu}M$. The linear dynamic range was from 10 to $200{\mu}M$ for cyanide with correlation coefficients higher than 0.99. For quality control samples at four different concentrations including LLOQ that were analyzed in quintuplicate, on six separate occasions, the accuracy and precision range from -14.1 % to 14.5% and 2.7 % to 18.3 %, respectively. The GC/MS-based method of analysis established in this study could be applied to the toxicokinetic study of cyanide on biological matrix substrates such as blood, urine, lung and skin tissues.

• Journal of Ecology and Environment
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• v.48 no.2
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• pp.144-151
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• 2024

Background: This study focused on the diet of Clithon retropictum, level II endangered species in Korea. Since the development of brackish water zones has led to a decline in the population of this species, to obtain information on the ecology of C. retropictum required for its conservation and restoration. To investigate the actual preys of C. retropictum in south coast of Korea, we conducted high-throughput sequencing and metabarcoding techniques to extract DNA from gut contents and periphyton in their habitats. Results: Total 118 taxonomic groups were detected from periphyton samples. 116 were Chromista and Cyanobacteria dominated in the most samples. In gut contents samples, 98 taxonomic groups were detected. Similar to the results of periphyton, 96 were Chromista and Cyanobacteria dominated in the most samples. In the principal component analysis based on the presence/absence of taxonomic groups, gut content composition showed more clustered patterns corresponding to their habitats. Bryophyta was the most crucial taxonomic group explaining the difference between periphyton and gut contents compositions of C. retropictum. Conclusions: Our finding suggests that C. retropictum may not randomly consume epilithic algae but instead, likely to supplement their diet with Bryophyta.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.136-141
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• 2013

BACKGROUND: This study was performed to establishment the PHRLs of peach during cultivation period, and also to estimate biological half-lives for residues of fenarimol and flufenoxuron. METHODS AND RESULTS: The extracted samples of fenarimol were analyzed by GC-ECD and the flufenoxuron extracted samples were analyzed by HPLC-DAD. Recoveries of fenarimol at two fortification levels of 0.1 mg/kg, 0.5 mg/kg were $93.69{\pm}6.56$(%) and $94.45{\pm}1.60$ (%), respectively. And recoveries of flufenoxuron at two fortification levels of 0.1 mg/kg, 0.5 mg/kg were $106.73{\pm}5.90$(%) and $96.37{\pm}6.66$(%), respectively. CONCLUSION(S): The biological half-lives of fenarimol in single treatment and triple treatment were 3.5day and 3.8day. that of Flufenoxuron was also 7.1day and 4.9day, respectively. The PHRL of fenarimol were recommended as 1.5 mg/kg for 10day before harvest and the PHRL of flufenoxuron were recommended as 1.4 mg/kg for 10day before harvest.