• 한국균학회소식:학술대회논문집
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• 2016.05a
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• pp.35-35
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• 2016

A mycotoxin is a toxic secondary metabolite produced by organisms of the fungus kingdom, commonly known as molds and has been widely contaminated in agricultural products such as grains and cereals. Many methods including high performance liquid chromatography (HPLC) and gas chromatography (GC) have already been proposed and reviewed for mycotoxins. These methods are either expensive or time-consuming due to the complication of sample preparation and pre-concentration before determination. In addition, both methods are unsuitable for the routine screening of large sample numbers. A biosensor is a fictive analytical device that combines a biological component with a physicochemical detector for the detection of an analyte. Biosensors represent a rapidly expanding field, at the present time, with an estimated 60% annual growth rate; the major impetus coming from the health-care industry but with some pressure from other areas, such as food safety and environmental monitoring. Antibodies and aptamers are bioreceptors which have been used in the development of biosensors. There are many kinds of antibodies and aptamers specific to mycotoxin, and antibody (or aptamer)-based biosensors have been successfully developed for the detection of mycotoxin. The biosensors permit the rapid, sensitive, simple, and on-site detection of a range of mycotoxins and can be an alternative method to traditional methods such as HPLC and GC. This presentation provides the development trends of biosensors to mycotoxins and their application to food and agricultural products.

• Applied Biological Chemistry
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• v.39 no.6
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• pp.419-423
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• 1996

We have established the quantitative method for assay antimutagenic activity from natural products using SOS chromotest technique. Establishment of the method in this study makes it possible to numerize antimutagenic activities from samples in term of the sample amount required for 50% inhibition to mutagenic activity induced by the chemical mutagen under the standard assay condition. Antimutagenic activities of rices from different cultivars as well as other cereals were assayed through this method. The results revealed that antimutagenic activities of mutant cultivar, Suwon 393(Hyangdo) and Sanghaehyanghyulla(Jado), were higher than Chuchung which mainly consumed for steamed rice, and also indicated that antimutagenic activities of cereals, such as job'tear, buckwheat, small red bean, black bean were generally higher than that of brown rice.

• Analytical Science and Technology
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• v.13 no.2
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• pp.136-150
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• 2000

For the identification of unknown drugs in biological samples, we attempted rapid high performance thin layer chromatographic method which is sensitive and selective chromatographic analysis of high performance thin layer chromatography (HPTLC) with automated TLC sampler and ultra-violet (UV) scanner. We constructed HPTLC database (DB) on two hundred five drugs by using the data of Rf values and UV spectra (scan 200-360 nm) as well as gas chromatography/mass spectrometry (GC/MS) DB on ninety six drugs by using the data of relative retention time (RRT) on lidocain and mass spectra. After extracting drugs in biological sample by solid phase extraction (Clean Screen ZSDAU020), we applied them to HPTLC and GC/MS DB. Drugs, especially extracted from biological samples, showed good matching ratio to HPTLC DB and these drugs were confirmed by GC/MS. In conclusion, this DB system is thought to be very useful method for the screening of unknown drugs in biological samples.

• Applied Biological Chemistry
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• v.47 no.4
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• pp.396-402
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• 2004

For industrial application to manufacturing functional foods for health using browned oak mushroom, we examined its reducing power, inhibitory effect on intracellular reactive oxygen species, phenolic compounds and phytates contents, modulatory effects on NO radical and matrix metalloproteinase 9 (MMP9) generation by activated macrophages, and antimutagenicity in order to evaluate the functionality of browned oak mushroom for health. While overall ethanolic extracts have higher reducing power than aqueous extracts, browning reaction was found to increase reducing power by up to 28% at a 3.32 mg/ml sample concentration. Browning reaction also increased phenolic compound content by about 73% compared to raw mushroom. However, any significant change in phytate content could not be detected. At a concentration of $100\;{\mu}g/ml$, treatment of ethanolic extract of oak mushroom increased NO generation over 43% in LPS-stimulated macrophage. On the contrary, the aqueous extracts rather decreased it over 17% at the same sample dose. However, any solvent extract from browned oak mushroom seems not to cause any change in both NO production and MMP9 activity. In addition, browning reaction did not allow any significant change in suppressive effect on mitomycin C-induced mutagenesis as examined with SOS chromotest. These results suggest a possible use of browned oak mushroom with unmarketable quality as a material for development of a variety of processed functional foods for health.

• Journal of Food Hygiene and Safety
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• v.18 no.2
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• pp.51-55
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• 2003

A germination method was used to detect biological changes in gamma-irradated apple, orange, and lemon at low doses at 0.1, 0.3, 0.5, 0.7, and 1.0 kGy. Ten fruit seeds of each sample were placed on moistened cotton and germinated at 3$0^{\circ}C$ for 7 days. Shoot lengths of all fruits were gradually grown for 7 days, but the growth was signficantly slow down by fifth day. During 7 days of germination, the growth of unirradiated fruits were significantly highter than the irradiated fruits. By examining the gamma-Irradiated fruits in this study, a germination method could be possibly one of the screening test to identify irradiated fruits.

• Environmental Analysis Health and Toxicology
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• v.11 no.1_2
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• pp.31-39
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• 1996

Leachate from municipal solid waste (MSW) landfill, effluent from leachate treatment plant, and ground water sample from a monitoring well near landfill site were tested for an acute toxicity. Microtox toxicity test was used for testing the acute toxicity of leachate and other samples. EC$_{50}$ values which a concentration of pollutant for reducing 50% light output from luminescent bacteria, Photobacterium phosphoreum were determined to assess the toxicity of pollutants as well as the relative toxicity. In addition, characteristics of leachate were studied and compared to those of phenol and pentachlorophenol (PCP) which are typical aquatic toxic pollutants. For leachate, EC$_{50}$ for 30 min incubation was 10.8%, while for phenol and PCP, 46 ppm and 1.2 ppm, respectively. the relative toxicity of treated leachate by in situ aeration with activated sludge was reduced to more than 75% of toxicity of the untreated leachate. Microtox toxicity test was failed to figure out EC$_{50}$ values for groundwater from a monitoring well since the relative toxicity of the unconcentrated sample was too low to estimate EC$_{50}$. Addition of activated carbon to leachate was reduced the relative toxicity. The reduction Pattern of the relative toxicity of leachate by mechanical aeration was similar to that of PCP, but different from that of phenol. These findings suggest that the toxicity of leachate may come from PCP-like toxic compounds rather than phenol-like one. In conclusion, the process of aeration with activated sludge might be very important to reduce the environmental toxicity of leachate. And Microtox test could be a reasonable bioassay for screening and monitoring the environmental toxicity of leachate from municipal solid waste landfill as well as for determining the reduction efficiency of the leachate toxicity by various treatment processes in leachate treatment plant.

• Applied Biological Chemistry
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• v.11
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• pp.43-47
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• 1969

With an attempt to obtain a glucose isomerizing enzyme producing microorganism, one hundred and thirty-three strains of microorganism were isolated from soil samples. After screening, a strain K-17 which belonging to actinomyces family, was finally selected. Using this strain of K-17, sugars produced from glucose by the reaction of sugar isomerizing enzyme were tested with paper chromatography. Only a kind of resulting sugar, fructose, was detected from enzyme reaction sample and other sugars were never detected. By these results, the enzyme produced by strain K-17 is classified as a glucose isomerase.

• Applied Biological Chemistry
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• v.38 no.6
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• pp.584-589
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• 1995

To select new useful plants with antibacterial activity, ninety five sample of eighty different species of wild plants were collected, and extracted with methanol. Antibacterial activity of the methanol extracts was tested against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Vibrio parahaemolyticus. The methanol extracts from Artemisia capillaris, Hemistepta lyrata, Youngia japonica, Prunella vulgaris, Lamium amplexicaule and Juniperus chinensis was effective against all bacterial strains tested, and eight methanol extracts including Ixeris dentata, Gnaphalium affine, Chelidonium majus and Spiraea prunifolia exhibited the antibacterial activity against at least 3 bacterial strains. Methanol extracts from leaf of Syringa vulgaris, Drava nemorosa and clove of Erythronium japonicum showed a selective antibacterial activity against two gram negative bacteria, V. parahaemolyticus, and B. subtilis, respectively. With investigations on antibacterial activity against a certain bacterial strains tested, metahnol extracts from clove of Erythronium japonicum, Spiraea prunifolia, leaf and twig of Camelia japonica, and Drava nemorosa showed strongest activities against B. subtilis, S. aureus, E. coli, and V. parahaemolyticus, respectively. Nine methanol extracts based on the results were successively fractionated with n-hexane, chloroform, ethyl acetate and water portions, which were examined antibacterial activity against B. subtilis and V. parahaemolyticus. Among the all fractions tested, chloroform fractions of Hemistepta lyrata showed strongest antibacterial activity against both B. subtilis (17mm) and V. parahaemolyticus (29 mm). Chloroform fractions of Youngia japonica, n-hexane fractions of Artemisia capillaris, Iexeris dentata and Prunella vulgaris, and ethyl acetate fraction of leaf and twig of Camelia japonica showed relatively a strong antibacterial activity. On the other hand, Juniperus chinensis and Equisetum arvense was distributed to all fractions except for water fraction.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2000.11a
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• pp.21-22
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• 2000

Expressed sequence tags (EFTs) are the partial segments of cDNA produced from 5 or 3 single-pass sequencing of cDNA clones, error-prone and generated in highly redundant sets. Advancement and expansion of Genomics made biologists to generate huge amount of ESTs from variety of organisms-human, microorganisms as well as plants, and the cumulated number of ESTs is over 5.3 million, As the EST data being accumulate more rapidly, it becomes bigger that the needs of the EST analysis tools for extraction of biological meaning from EST data. Among the several needs of EST analyses, the extraction of protein sequence or functional motifs from ESTs are important for the identification of their function in vivo. To accomplish that purpose the precise and accurate identification of the region where the coding sequences (CDSs) is a crucial problem to solve primarily, and it will be helpful to extract and detect of genuine CD5s and protein motifs from EST collections. Although several public tools are available for EST analysis, there is not any one to accomplish the object. Furthermore, they are not targeted to the plant ESTs but human or microorganism. Thus, to correspond the urgent needs of collaborators deals with plant ESTs and to establish the analysis system to be used as general-purpose public software we constructed the pipelined-EST analysis system by integration of public software components. The software we used are as follows - Phred/Cross-match for the quality control and vector screening, NCBI Blast for the similarity searching, ICATools for the EST clustering, Phrap for EST contig assembly, and BLOCKS/Prosite for protein motif searching. The sample data set used for the construction and verification of this system was 1,386 ESTs from human intrathymic T-cells that verified using UniGene and Nr database of NCBI. The approach for the extraction of CDSs from sample data set was carried out by comparison between sample data and protein sequences/motif database, determining matched protein sequences/motifs that agree with our defined parameters, and extracting the regions that shows similarities. In recent future, in addition to these components, it is supposed to be also integrated into our system and served that the software for the peptide mass spectrometry fingerprint analysis, one of the proteomics fields. This pipelined-EST analysis system will extend our knowledge on the plant ESTs and proteins by identification of unknown-genes.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.71-80
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• 2001

Blood and urine mercury level of three workers were monitored during 60~80 days after high exposure to mercury at the silver refining plant. Mercury was used to form silver-mercury amalgam from plating sludge. Workers were exposed to mercury about 70 days at the several processes, such as hand held weaving, vibration table, and heating from the furnace. mercury was analysed by atomic absorption spectroscopy-vapor generation technique. Recovery from the biological sample was 95.51% and pooled standard deviation was 0.033. At the time of study, there was no work at the workplace. So, airborne mercury concentration was measured with area sampling 5 days after the work, ranged from 0.1459 to 1.2351 mg/㎥(Arithmatic mean 0.4711 mg/㎥, Geometric mean 0.3566 mg/㎥) at the inside of the plant, that is far above the ACGIH's TLV(0.025 mg/㎥) and ranged from 0.0073 to 0.0330 mg/㎥ at the outdoor. Blood mercury levels at the beginning of the monitoring were 4~14 times greater than the American Conference of Governmental Industrial Hygienists Biological Exposure Index(ACGIH BEI, 15 ug/L). Blood mercury levels were decreased logarithmically, that is, rapidly at the high level and slowly at the low level but sustained above the level of the ACGIH BEI 60~80 days after the work. Urine mercury levels at the beginning of the monitoring were 8~16 times greater than the ACGIH BEI(35 ug/g creatinine). Urine mercury levels were decreased logarithmically, but correlation between urine level and off-days were lower than those of blood. Decreasing pattern of blood mercury levels were little affected than that of urine levels when the chelating agent, D-penicillamine, was administered. There was correlation between blood mercury level and urine mercury level(0.81~0.83) but it didn\`t mean that the highest blood mercury level corresponded the highest urine mercury level. In our study, Case 1 always shows the highest level in urine but case 3 always shows the highest level in blood. Creatinine correction represented better correlations between urine mercury levels and blood levels, and between urine levels and off-days rather than by urine volume. Spot urine sampling had a wide variation than that of whole day urine sampling. So, We recommend spot urine sampling for screening and whole day urine sampling for exact diagnosis.