• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.290-295
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• 2019

Salmonella spp. are frequently associated with food and are among the most important foodborne pathogens. The recent Salmonella out breaks in Korea was associated with chocolate mousse cakes served with school meals during September 2018. The objective of this research was to compare the 3M Molecular Detection Assay 2 - Salmonella and the Korean Standard Method of Salmonella in artificially inoculated mousse (chocolate and cheese) and tiramisu cakes. Mousse (chocolate and cheese) and tiramisu cakes were artificially inoculated with S. Typhimurium. Twenty five gram of sample was enriched with 225 mL buffered peptone water for incubation at $37^{\circ}C$ for 24 h. After enrichment, the cultures were analyzed by using the 3M Molecular Detection Assay 2 - Salmonella and the Korean Standard Method. Most of the inoculated samples showed similar results except the chocolate mousse cakes, in which real-time PCR was unable to detect S. Typhimurium even after $10^4CFU/25g$ of inoculation. However, S. Typhimurium inoculated at a concentration of $10^0CFU/25g$ was detected by using 3M Molecular Detection Assay 2 - Salmonella. In chocolate mousse, detection of S. Typhimurium using real-time PCR was partially successful when dark chocolate was added at less than 15%. Negative results in real-time PCR and 3M Molecular Detection Assay 2 - Salmonella were confirmed by gel electrophoresis. The data indicated that dark chocolate could inhibit amplification of the target gene in the PCR reactions. In conclusion, the 3M Molecular Detection Assay 2 - Salmonella was better than the Korean Standard Method (real-time PCR) for the detection of S. Typhimurium in chocolate mousse cakes and chocolate mousse.

• Molecular & Cellular Toxicology
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• v.2 no.4
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• pp.244-250
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• 2006

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 genotoxicity of 3 synthetic chemicals was evaluated in L5178Y $tk^{+/-}$ mouse lymphoma cells in vitro. 9H-carbazole (CAS No. 86-74-8) did not induce significant mutation frequencies both in the presence and absence of metabolic activation system. 1, 3-Dichloro-2-propanol (CAS No. 96-23-1) revealed a significant increase of mutation frequencies in the range of $625-373\;{\mu}g/mL$ in the absence of metabolic activation system and $157-79\;{\mu}g/mL$ in the presence of metabolic activation system. And also, fenpropathrin (CAS No. 64257-84-7) appeared the positive results only in the absence of metabolic activation system. Through the results of MLA tk assay with 3 synthetic chemicals in L5178Y cells in vitro, we may provide the important clues on the genotoxic potentials of these 3 chemicals.

• Bulletin of the Korean Chemical Society
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• v.26 no.6
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• pp.939-942
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• 2005

For the detection of cyanobacterial toxin, an Enzyme-linked immunosorbent assay (ELISA) was integrated into a PDMS microchip. The conjugates of microcystin-LR (MCLR) and keyhole limpet hemocyanin (KLH) were adsorbed on the surface of polystyrene beads and these MCLR-KLH polystyrene beads were introduced into a microchamber. MCLR on the surface of polystyrene beads reacted with horseradish peroxides (HRP) conjugated anti-MCLR monoclonal antibody (mAb) which had a competitive reaction with MCLR in water sample. After the enzyme substrate 3,3,5,5-tetramethyl benzidine (TMB) was injected into the chamber and catalyzed by HRP, the color change was detected with a liquid-cord waveguide. This integration shortened the conventional ELISA analysis time from several hours to about 30 min with only 4.2 $\mu$L MCLR sample consuming which was useful for the environmental analysis. More over, troublesome operations required for ELISA could be replaced by simple operations. The microchip based detection system showed a good sensitivity of 0.05 $\mu$g/L and maintained good reliability through its quantitative range with low coefficients of variation (2.5-10.5%).

• Molecular & Cellular Toxicology
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• v.2 no.2
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• pp.89-96
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• 2006

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 11 synthetic chemicals was evaluated in Chinese hamster lung fibroblast cells in vitro. 1-Chloro-3-bromopropane CAS No. 109-70-6) induced chromosomal aberrations with significance at the concentration of $185.0\;{\mu}g/mL\;and\;1,600\;{\mu}g/mL$ both in the presence and absence of metabolic activation system, respectively. Triphenyl phosphite (CAS No. 101-02-0), which is one of the most cytotoxic chemical among 11 chemicals tested revealed no clastogenicity in the range of $95.0-4.9\;{\mu}g/mL$ both in the presence and absence of metabolic activation system. From the results of chromosomal aberration assay with 11 synthetic chemicals in Chinese hamster lung cells in vitro, 1-chloro-3-bromopropane revealed a positive clastogenic result in this study.

• Journal of Plant Biotechnology
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• v.45 no.4
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• pp.322-327
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• 2018

Post-translational modification of proteins regulates signaling cascades in eukaryotic system, including plants. Among these modifications, phosphorylation plays an important role in modulating the functional properties of proteins. Plants perceive environmental cues that directly affect the phosphorylation status of many target proteins. To determine the effect of environmentally induced phosphorylation in plants, in vivo methods must be developed. Various in vitro methods are available but, unlike in animals, there is no optimized methodology for detecting protein phosphorylation in planta. Therefore, in this study, a robust, and easy to handle Phos-Tag Mobility Shift Assay (PTMSA) is developed for the in vivo detection of protein phosphorylation in plants by empirical optimization of methods previously developed for animals. Initially, the detection of the phosphorylation status of target proteins using protocols directly adapted from animals failed. Therefore, we optimized the steps in the protocol, from protein migration to the transfer of proteins to PVDF membrane. Supplementing the electrophoresis running buffer with 5mM $NaHSO_3$ solved most of the problems in protein migration and transfer. The optimization of a fast and robust protocol that efficiently detects the phosphorylation status of plant proteins was successful. This protocol will be a valuable tool for plant scientists interested in the study of protein phosphorylation.

• Journal of Microbiology
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• v.44 no.1
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• pp.42-49
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• 2006

In this study, we describe our newly-developed sensitive two-stage PCR procedure for the detection of 13 common mycoplasmal contaminants (M. arthritidis, M. bovis, M. fermentans, M. genitalium, M. hominis, M. hyorhinis, M. neurolyticum, M. orale, M. pirum, M. pneumoniae, M. pulmonis, M. salivarium, U. urealyticum). For primary amplification, the DNA regions encompassing the 16S and 23S rRNA genes of 13 species were targeted using general mycoplasma primers. The primary PCR products were then subjected to secondary nested PCR, using two different primer pair sets, designed via the multiple alignment of nucleotide sequences obtained from the 13 mycoplasmal species. The nested PCR, which generated DNA fragments of 165-353 bp, was found to be able to detect 1-2 copies of the target DNA, and evidenced no cross-reactivity with the generated DNA of related microorganisms or of human cell lines, thereby confirming the sensitivity and specificity of the primers used. The identification of contaminated species was' achieved via the performance of restriction fragment length polymorphism (RFLP) coupled with Sau3AI digestion. The results obtained in this study furnish evidence suggesting that the employed assay system constitutes an effective tool for the disagnosis of mycoplasmal contamination in cell culture systems.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.260-262
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• 2002

The determination of DNA hybridization can apply the molecular biology research. clinic diagnostics. bioengineering, environment monitoring, food science and other application area. So, The determination of hybridization is very important for the improvement of DNA detection system. In this study, we report the characterization of the DNA hybridization by the electricalchemical methods. The probe oligonucleotide was used to determine the amount of target oligonucleotide in solution using Methylen Blue(MB) as the electrochemical indicators. The cathodic peak currents($I_{peak}$) of MB were linearly related to the concentration of the target oligonucleotide sequence in the range $1[{\mu}M]{\sim}0.1[{\mu}M]$. The detection limit of this approach was 0.01[nM]. As a result, the match oligonucleotide(CR-1) was most stable state and the peak of redox current measured by DNA hybridization detection sensors by using electrochemical method seem to be similar to 1-mer terminal mismatch oligonucleotide(MR-3). The MR-2, MR-3, MR-22 and MR-33 have each mismatching sequence of central and terminal. With this set the role of point mutations was to be investigated. Terminal mismatch oligonucleotide (MR-3, 33) is shown more stable state than central mismatch oligonucleotide(MR-2, 22). And 1-mer mismatch oligonucleotide(MR-2 or 3) is shown more stable state than 2-mer mismatch oligonucleotide(MR-22 or 33).

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.1
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• pp.35-39
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• 2019

Purpose Hepatitis B virus (hepatitis B virus, HBV) infection is a worldwide major public health problem and it is known as a major cause of chronic hepatitis, liver cirrhosis and liver cancer. And serologic tests of hepatitis B virus is essential for diagnosing and treating these diseases. In addition, with the development of molecular diagnostics, the detection of HBV DNA in serum diagnoses HBV infection and is recognized as an important indicator for the antiviral agent treatment response assessment. We performed HBeAg assay using Immunoradiometric assay (IRMA) and Chemiluminescent Microparticle Immunoassay (CMIA) in hepatitis B patients treated with antiviral agents. The detection rate of HBV DNA in serum was measured and compared by RT-PCR (Real Time - Polymerase Chain Reaction) method Materials and Methods HBeAg serum examination and HBV DNA quantification test were conducted on 270 hepatitis B patients undergoing anti-virus treatment after diagnosis of hepatitis B virus infection. Two serologic tests (IRMA, CMIA) with different detection principles were applied for the HBeAg serum test. Serum HBV DNA was quantitatively measured by real-time polymerase chain reaction (RT-PCR) using the Abbott m2000 System. Results The detection rate of HBeAg was 24.1% (65/270) for IRMA and 82.2% (222/270) for CMIA. Detection rate of serum HBV DNA by real-time RT-PCR is 29.3% (79/270). The measured amount of serum HBV DNA concentration is $4.8{\times}10^7{\pm}1.9{\times}10^8IU/mL$($mean{\pm}SD$). The minimum value is 16IU/mL, the maximum value is $1.0{\times}10^9IU/mL$, and the reference value for quantitative detection limit is 15IU/mL. The detection rates and concentrations of HBV DNA by group according to the results of HBeAg serological (IRMA, CMIA)tests were as follows. 1) Group I (IRMA negative, CMIA positive, N = 169), HBV DNA detection rate of 17.7% (30/169), $6.8{\times}10^5{\pm}1.9{\times}10^6IU/mL$ 2) Group II (IRMA positive, CMIA positive, N = 53), HBV DNA detection rate 62.3% (33/53), $1.1{\times}10^8{\pm}2.8{\times}10^8IU/mL$ 3) Group III (IRMA negative, CMIA negative, N = 36), HBV DNA detection rate 36.1% (13/36), $3.0{\times}10^5{\pm}1.1{\times}10^6IU/mL$ 4) Group IV(IRMA positive, CMIA negative, N = 12), HBV DNA detection rate 25% (3/12), $1.3{\times}10^3{\pm}1.1{\times}10^3IU/mL$ Conclusion HBeAg detection rate according to the serological test showed a large difference. This difference is considered for a number of reasons such as characteristics of the Ab used for assay kit and epitope, HBV of genotype. Detection rate and the concentration of the group-specific HBV DNA classified serologic results confirmed the high detection rate and the concentration in Group II (IRMA-positive, CMIA positive, N = 53).

• Journal of Periodontal and Implant Science
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• v.36 no.4
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• pp.839-847
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• 2006

The aim of this study is to monitor reporter gene expression under osteocalcin gene promoter, using a real-time molecular imaging system, as tool to investigate osteoblast differentiation. The promoter region of mouse osteocalcin gene 2 (mOG2), the best-characterized osteoblast-specific gene, was inserted in promoterless luciferase reporter vector. Expression of reporter gene was confirmed and relationship between the reporter gene expression and osteoblastic differentiation was evaluated. Gene expression according to osteoblstic differentiation on biomaterials, utilizing a real-time molecular imaging system, was monitored. Luciferase was expressed at the only cells transduced with pGL4/mOGP and the level of expression was statistically higher at cells cultured in mineralization medium than cells in growth medium. CCCD camera detected the luciferase expression and was visible differentiation-dependent intensity of luminescence. The cells produced osteocalcin with time-dependent increment in BMP-2 treated cells and there was difference between BMP-2 treated cells and untreated cells at 14days. There was difference at the level of luciferase expression under pGL4/mOGP between BMP-2 treated cells and untreated cells at 3days. CCCD camera detected the luciferase expression at cells transduced with pGL4/mOGP on Ti disc and was visible differentiation-dependent intensity of luminescence This study shows that 1) expression of luciferase is regulated by the mouse OC promoter, 2) the CCCD detection system is a reliable quantitative gene detection tool for the osteoblast differentiation, 3) the dynamics of mouse OC promoter regulation during osteoblast differentiation is achieved in real time and quantitatively on biomaterial. The present system is a very reliable system for monitoring of osteoblast differentiation in real time and may be used for monitoring the effects of growth factors, drug, cytokines and biomaterials on osteoblast differentiation in animal.

• Parasites, Hosts and Diseases
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• v.52 no.2
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• pp.137-142
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• 2014

Serologic tests are widely accepted for diagnosing Toxoplasma gondii but purification and standardization of antigen needs to be improved. Recently, surface tachyzoite and bradyzoite antigens have become more attractive for this purpose. In this study, diagnostic usefulness of 3 recombinant antigens (SAG1, SAG2, and SAG3) were evaluated, and their efficacy was compared with the available commercial ELISA. The recombinant plasmids were transformed to JM109 strain of Escherichia coli, and the recombinants were expressed and purified. Recombinant SAG1, SAG2, and SAG3 antigens were evaluated using different groups of sera in an ELISA system, and the results were compared to those of a commercial IgG and IgM ELISA kit. The sensitivity and specificity of recombinant surface antigens for detection of anti-Toxoplasma IgG in comparison with commercially available ELISA were as follows: SAG1 (93.6% and 92.9%), SAG2 (100.0% and 89.4%), and SAG3 (95.4% and 91.2%), respectively. A high degree of agreement (96.9%) was observed between recombinant SAG2 and commercial ELISA in terms of detecting IgG anti-Toxoplasma antibodies. P22 had the best performance in detecting anti-Toxoplasma IgM in comparison with the other 2 recombinant antigens. Recombinant SAG1, SAG2, and SAG3 could all be used for diagnosis of IgG-specific antibodies against T. gondii.