• Journal of Food Hygiene and Safety
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• v.22 no.4
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• pp.248-256
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• 2007

In this study, the competitive polymerase chain reaction (cPCR) was used to develop a direct enumeration method of Salmonella spp. in pork meat. After comparing three DNA extraction methods, the modified guanidine thiocyanate-phenol-chloroform method was chosen for Salmonella DNA extraction in artificially inoculated pork meat. The previously reported 284-bp invA gene (Rahn et al. Mol. Cell. Probes 1992) was tested for specificity, and 57 Salmonella strains and 24 non-Salmonella strains were evaluated. All Salmonella strains tested were invA positive, and all non-Salmonella strains produced no false positive amplification products. The detection limit achieved was as low as 1,460 colony-forming units (cfu) per 0.1g of pork meat. For cPCR, the invA gene, which features a 82 bp-deletion, was cloned in the pGEM-4Z vector. A known amount of competitor DNA, which has the same primer binding sites, was co-amplified with Salmonella chromosomal DNA from the artificially inoculated pork meat. The cell-number determined by cPCR was approximately equal to the cfu from the most probable number (MPN) method. Finally, the whole procedure took only 5 hr.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.165-171
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• 2001

New visible and fast assay system have been developed for tobacco transformant introduced with adenosine deaminase (ADA) marker gene, which converts cytotoxic adenosine analogues to non-toxic inosine analogues and ammonia. Ammonia was changed to blue color in the solution of phenol-nitoprusside and alkaline-hypochlorite. It was possible to detect activity of ADA visibly on the holes of 96 well plate using tiny explant of transgenic tobacco leaves within 1 hour incubation time. As substrates of ADA enzyme from transgenic plant on the plate, a number of adenosine analogues such as 9-D-arabinofuranosyl adenine, cordycepin, 2'-deoxyadenosine, adenosine and xylofuranosyl adenine were possible for detection of ADA activity. Optimal condition of substrate for ADA enzyme was each 10 mM and pH 7.5 in adenosine solution. Especially, transgenic plant did not convert adenosine to inosine and ammonia in the presence of ADA inhibitor deoxycoformycin, which means that ammonia produced from transgenic plant is due to expression of ADA gene. Now, we show that this detection system can be easily, sensitively, fast and cheaply as well as visibly assayed in vitro as GUS gene system with very small size of transformant explant.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.6
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• pp.349-354
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• 2006

The aromatic hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates many of the biological and toxicological effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin) and related chemicals. The application of recombinant reporter plasmid such as the firefly luciferase gene has proven to be a very effective method to detect these chemicals. The bioassay system, CALUX, is sensitive in directly detecting AhR-agonists from a variety of environmental and biologic materials. However, responses of the AhR-dependent bioassays are dependent on the cell types used. Thus, we developed a sensitive bioassay using the recombinant mouse hepatoma cell (Hepa1c1c7) for the determination of dioxins. The recombinant cell line was stably transfected with firefly luciferase reporter gene (pGudLuc1.1). The transfected cells showed the highest induction of luciferase activity at 4.5 hr and a decrease beyond this time point. The system showed the highest sensitivity of detection ever reported. Upon TCDD exposure cells showed 2 fold increase at 10 pM and 7 fold increase at 100 pM, respectively. The passage number after the transfection played an important role in the sensitivity. The increase of passage number tended to increase the sensitivity of the cells up to 15. The media without phenol red showed a higher induction rate than with phenol red, suggesting the preferable use of phenol red-free media for the bioassay. Since each of the assays has unique characteristics that make them suitable for some screening applications and not others, development of sensitive bioanalytical methods based on a variety of cellular systems in a key to the successful determination of dioxins. The bioassay system developed in this study will contribute to further development of successful screening the AhR agonists among the environmental mixture. In addition, the rapid and sensitive nature of this cellular system can be applied as a valuable tool to screen the dioxin-like moieties among the prodrugs at the initial stage, thereby expediting the new drug discovery.

• Environmental Mutagens and Carcinogens
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• v.22 no.3
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• pp.149-156
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• 2002

The detection of many synthetic chemicals used in industry that may pose a genetic hazard in our environment is of great concern at present. Since these substances are not limited to the original products, and enter the environment, they have become widespread environmental pollutants, thus leading to a variety of chemicals that possibly threaten the public health. In this respect, to regulate and to evaluate the chemical hazard will be important to environment and human health. The clastogenicity of 18 synthetic chemicals was evaluated in Chinese hamster lung fibroblast cells in vitro. 4-Chloro-3,5-dimethyl phenol (CAS No. 88-04-0) induced chromosomal aberrations with significance at the concentration of 15.7 $\mu\textrm{g}$/$m\ell$ both in the presence and absence of metabolic activation system. Phenoxybenzene (CAS No. 101-84-8) which is one of the most cytotoxic chemical among 18 chemicals tested revealed no clastogenicity in the range of 0.11-0.43 $\mu\textrm{g}$/$m\ell$ both in the presence and absence of metabolic activation system. From the results of chromosomal aberration assay with 18 synthetic chemicals in Chinese hamster lung cells in vitro, 4-chloro-3,5-dimethyl phenol (CAS No. 88-04-0) revealed weak positive clastogenic results in this study.

• YAKHAK HOEJI
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• v.44 no.5
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• pp.416-423
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• 2000

There is a growing concern that a wide variety of chemicals released into the environment can disrupt the endocrine system of fish, wildlife and humans. Endocrine disrupting chemicals (EDCs) include pesticides such as DDT lindane and atrazine, the food packaging chemicals, phthalates and bisphenol A, alkylphenol ethoxylate detergents and the chemical industry by-products, dioxins. Xenoestrogens in the environment have been argued about health risk, because of estrogen mimetic chemicals are exposed only small amounts to human. A number of in vivo and in vitro assays are now in use to assess the activity of xenoestrogens in the environment. A human breast cancer cell line (MCF-7) was used to develop in vitro screening assay for the detection of xenoestrogenic environmental pollutants. The E-SCREEN (MCF7-BUS) assay is proposed as a reliable, easy and rapid-to-perform method. To optimize and validate this method before it can be used routinely, several phenol compounds and pesticides suspected to be estrogenic were tested using I-SCREEN assay. The results showed that this method is a valuable tool for screening potential estrogen-mimicking environmental pollutants and quantitative determination of estrogeniciy.

• The Korean Journal of Pesticide Science
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• v.3 no.2
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• pp.37-46
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• 1999

In order to ascertain the safety of the systemic insecticide carbofuran-treated crops, samples of garlic, peanut and potato were collected randomly from markets located in the main producing areas and analyzed for the residue of carbofuran and its main metabolite, 3-hydroxycarbofuran. The in vitro metabolism of carbofuran in phosphate buffer extracts of the crops was investigated. Two (M-12 and M-16) out of 20 mature garlic samples contained 0.13 and 0.07 mg/kg of carbohran, respectively, showing a detection incidence of 10%. The residue levels were less than the maximum residue limit (0.5 ppm) set by Korean Food and Drug Administration. Only one sample of mature garlic (M-12) out of 20 contained 0.13 mg/kg of 3-hydroxycarbofuran. The residues of carbofuran and 3-hydroxycarbofuran in the immature garlic, peanut and potato samples were less than the detection limits, 0.02 mg/kg for carbofuran and 0.06 mg/kg for 3-hydroxycarbofuran. The application of carbofuran to the fields of garlic, peanut and potato would be safe, considering that the estimated maximum acceptable daily intake of carbofuran from garlic was 0.0013 mg which is 0.24% of the maximum acceptable daily intake (0.55 mg). Carbofuran was hydrolyzed in vitro mainly to carbofuran phenol (m/z 164) in the respective phosphate buffer extracts of the three crops in contrast to the major oxidative metabolism in situ. The amount of the metabolite increased with the incubation time.

• Bulletin of the Korean Chemical Society
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• v.26 no.2
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• pp.297-302
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• 2005

The determination of total phenols was accomplished by capillary-high performance liquid chromatography (capillary-HPLC) after nitrosation of the U.S.E.P.A. classified 11 priority pollutant phenols, using the nitrosated parent phenol (POHNO) as a reference for calibration. The optimum mobile phase composition for this analysis was found by examining the effect of changing the percentage of acetonitrile (MeCN) in the mobile phase on retention factors (k values) and peak intensities. As MeCN percentage was increased, k values were reduced and peak intensities were generally increased. From the results obtained, it was found that the optimum mobile phase was 90%(v/v) MeCN solution at pH 8.0, the detection wavelength of 400 nm, and a detection limit (D.L., concentration at signal to noise ratio (S/N) of 3.0) of 4.5 ${\times}$ $10^{-7}$ M. In addition, 10 of the 11 phenols present in mineral or waste water were separated after the nitrosation by capillary-HPLC. The optimum mobile phase for separation was a 40%(v/v) MeCN solution at pH 5.0.

• Mycobiology
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• v.35 no.1
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• pp.21-24
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• 2007

To evaluate which dye is effective in a plate assay for detecting extracellular cellulase activity produced by fungi, four chromogenic dyes including remazol brilliant blue, phenol red, congo red, and tryphan blue, were compared using chromagepic media. For the comparison, 19 fungal species belonging to three phyla, ascomycota, basidiomycota, and zygomycota were inoculated onto yeast nitrogen-based media containing different carbon substrates such as cellulose (carboxylmethyl and avicel types) and cellobiose labeled with each of the four dyes. Overall, the formation of clear zone on agar media resulting from the degradation of the substrates by the enzymes secreted from the test fungi was most apparent with media containing congo red. The detection frequency of cellulase activity was also most high on congo red-supplemented media. The results of this study showed that congo red is better dye than other three dyes in, a plate assay for, fungal enzyme detection.

• Analytical Science and Technology
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• v.29 no.3
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• pp.114-125
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• 2016

In this study, 165 wastewater discharge facilities in 10 business types were investigated with regard to 24 specific hazardous substances that included heavy metals, VOCs, CN, and phenol in the Gwangju city. Cu in the range from from 0.008 to 35.420 mg/L was detected in all business types and the detection rate was 46.8 %. Other heavy metals, such as Cd, As, Hg, Pb, and Cr⁺⁶ were detected as well. However, their detection rates ranged between 0.6 and 1.8 %. CN and phenol were detected in one and five facilities, respectively. 12 species of VOCs were detected: chloroform 80.6 % (0.42 to 81.60 μg/L), benzene 16.4 % (1.49 to 3.31 μg/L), trichloroethylene 11.5 % (1.78 to 6.02 μg/L), 1,1-dichloroethylene 10.3 % (1.23 to 5.89 μg/L), and dichloromethane 8.5 % (0.28 to 968.86 μg/L) in the detection rate order. The concentration of VOCs was detected in trace amounts, except for dichloromethane that exceeded the effluent quality standard in three business types, namely, metal manufacturing, food industry, and car washing facility. Chloroform was detected in all business types, where 24.88 μg/L were detected in the laundry business and 53.41 μg/L in the water supply business; the mean concentration of chloroform in these two business types was higher than elsewhere. Therefore, for the disposal of non-degradable specific hazardous substances in industrial wastewater, it is necessary to introduce physical and chemical processes, such as activated carbon adsorption, fenton oxidation, ozone treatment, as well as photocatalyst and the UV radiation.

• Journal of Food Hygiene and Safety
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• v.32 no.4
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• pp.329-335
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• 2017

Analysis method was presented for the simultaneous determination of nine bisphenol A related compounds such as bisphenol A (BPA), phenol, p-tert-butylphenol, bisphenol A diglycidyl ether (BADGE), $BADGE{\cdot}2H_2O$, $BADGE{\cdot}2HCl$, bisphenol F diglycidyl ether (BFDGE), $BFDGE{\cdot}2H_2O$ and $BFDGE{\cdot}2HCl$ migrated from inner coatings of metal food cans by high performance liquid chromatography (HPLC) with fluorescence detection. The method was validated by examining the linearity of calibration curve, the limit of detection (LOD), the limit of quantification (LOQ), recovery and uncertainty. The migration tests of nine BPA related compounds were carried out with four food simulants; deionized water (DW), 4% acetic acid, 50% ethanol and n-heptane. There was not any compound detected in DW, 4% acetic acid and 50% ethanol at $60^{\circ}C$ for 30 min and n-heptane at $25^{\circ}C$ for 60 min. BPA and phenol were migrated into 4% acetic acid and 50% ethanol at $95^{\circ}C$ for 30 min. The concentrations were ranged from 0 to $10.77{\mu}g/L$ of BPA and from 0 to $2.35{\mu}g/L$ of phenol. Canned foodstuffs mostly have long-term shelf life. We investigated migration of nine BPA related compounds according to the variation in storage periods (0~90 days) and temperatures (4, 25 and $60^{\circ}C$). All compounds were not founded during 90 days at $4^{\circ}C$ and $25^{\circ}C$, respectively. However BPA and $BADGE{\cdot}2H_2O$ were founded in DW and 4% acetic acid at $60^{\circ}C$. The migration levels of BPA and $BADGE{\cdot}2H_2O$ were close to the value of LOQ, respectively and did not change significantly as storage period. It was founded from results that the migration of BPA related compounds from metal food cans was controlled to a safe level.