• Food Science of Animal Resources
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• v.37 no.4
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• pp.599-605
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• 2017

Korean native honey (KNH) is much more expensive than European honey (EH) in Korea, because KNH is a favored honey which is produced less than EH. Food fraud of KNH has drawn attention of the government office concerned, which is in need of a method to differentiate between KNH and EH which are produced by the Asiatic honeybee, Apis cerana and the European honeybee, Apis mellifera, respectively. A method to discriminate KNH and EH was established by using duplex polymerase chain reaction (PCR) in this study. Immunochromatographic assay (IC) was examined to analyze the duplex PCR product. The DNA sequences of primers for the duplex PCR were determined by comparing cytochrome C oxidase genes of the two honey bee species. Chelex resin method was more efficient in extracting genomic DNA from honey than the other two procedures of commercial kits. The duplex PCR amplifying DNA of 133 bp were more sensitive than that amplifying DNA of 206 bp in detecting EH in the honey mixture of KNH and EH. Agarose gel electrophoresis and IC detected the DNA of 133 bp at the ratios of down to 1% and 5% EH in the honey mixture, respectively and also revealed that several KNH products distributed by internet shopping sites were actually EH. In conclusion, the duplex PCR with subsequent IC could also discriminate between KNH and EH and save time and labor.

• Parasites, Hosts and Diseases
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• v.52 no.3
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• pp.257-261
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• 2014

Toxoplasma 3 main clonal lineages are designated as type I, II, and III; however, atypical and mixed genotypes were also reported. This study was conducted for detection of Toxoplasma gondii genotypes in rats (Rattus rattus) in Riyadh region, Saudi Arabia. PCR test on T. gondii B1 gene was conducted on ELISA IgM positive samples for confirmation of the infection. However, genetic analysis of the SAG2 locus was performed to determine T. gondii genotypes using PCR-RFLP technique. PCR test on T. gondii B1gene showed that 22 (81.5%) out of the 27 ELISA IgM positive samples have T. gondii DNA. Genotypic analysis shows that, of the total 22 PCR positive samples, only 13 (59.1%) were of type II, 7 (31.8%) were of type III, and 2 (9.1%) were of an unknown genotype. It is obvious that the prevalence of both type II and III is high in rats. No reports have been available on T. gondii genotypes among rats in Riyadh region, and only little is known about its seroprevalence in rats. Future studies on T. gondii genotypes in rats using multi-locus markers is needed in Riyadh region, Saudi Arabia for better understanding of T. gondii pathogenesis and treatment in humans and animals.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.4
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• pp.238-244
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• 2007

Nowadays many people are concerned about being healthy, and many dairy products are taken as health supplementary foods. Among dairy products, kefir, also called as Tibet mushroom, is a yogurt fermented by kefir grain, which is a mixture of lactic acid bacteria and yeasts. Although there are many empirical evidences that kefir is very influential for human body, the exact reason is not definitively discovered. Therefore, it would be useful to understand characteristics of a kefir grain and to categorize bacteria in a kefir grain. In this paper, molecular biological apparatus such as PCR, electrophoresis, PCR purification, DNA sequencing were used to identify and classify the species of lactic acid bacteria and yeast in a kefir grain. We used PCR-based identification method using 16S rRNA primer and Internal Transcribed Spacer (ITS) primer. We identified 6 different species which were selected on different medium. In addition, observation with scanning electron microscope (SEM) enabled us to grasp an external shape of the kefir grain. Although we found a limited number of microbial species, more intensive research are needed for extensive identification of microorganism species in Korean kefir grain.

• Biomedical Science Letters
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• v.27 no.4
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• pp.283-290
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• 2021

Severe acute respiratory syndrome coronavirus (SARS-CoV2) is a major coronavirus that infects humans with human Coronavirus (HuCoV)-229E, HCoV-OC43, HCoV-HKU1, HCoV-NL63, Severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle east respiratory syndrome coronavirus (MERS-CoV). SARS-CoV2 is currently a global pandemic pathogen. In this study, we developed conventional RT-PCR based diagnostic system for the detection of SARS-CoV2 which is relatively inexpensive but has high stability and a wide range of users. Three conventional RT-PCR primer sets capable of forming specific band sizes by targeting the ORF1ab [232 nucleotide (nt)], E (200 nt) and N (288 nt) genes of SARS-CoV2 were developed, respectively, and it were confirmed to be about 10~100 times higher detection sensitivity than the previously reported methods. In addition, a standard positive control that can generate specific amplicons by reacting with the developed RT-PCR primers and verify the false-positiv from contamination of the laboratory was produced. Therefore, the diagnostic system that uses the RT-PCR method is expected to be used to detect SARS-CoV2.

• Journal of Food Hygiene and Safety
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• v.18 no.1
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• pp.6-13
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• 2003

Various kinds of genetically modified organisms (GMO) and processed foods have been developed during recent years. Genetically modified organisms can be classified into several groups as their development methods. Generally, GMO has three foreign DNA regions such as gene expression adjustment region(Promoter), termination region (terminator) and structure gene. Detection of these regions can be done particularly by polymerase chain reaction (PCR). PCR-based detection can virtually be performed for any GMO within short of time. The most important prerequisite for the application of PCR-based detection is to decide abstraction method of efficient nucleic acids. Specially, in the case of processed food, because nucleic acids of foodstuffs are damaged by heat treatment (sterilization), pressure and fermentation, DNA must be extracted ken the samples prior to PCR analysis. Although many DNA extraction protocols are available, they have rarely been compared in a comprehensive method. In this study low widely used commercial and non-commercial DNA extraction methods-DNeasy$^{TM}$, Wizard$^{TM}$, CTAB, phenol/chloroform system-were compared with respect to the quality and yield of nucleic acids and insertion genes.nes.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.4 no.1
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• pp.34-40
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• 2001

Purpose: The purpose of this study was to evaluate the clinical efficacy of reverse transcription-polymerase chain reaction (RT-PCR) in detecting rotaviral gastroenteritis in children comparing with that of commercial immunoassays. Methods: Stools from 79 children admitted Korea University Hospital due to diarrhea were collected from December 1999 to February 2000. Immunoassays were done using commercial rotavirus Latex kit and Rotatec (ELISA) kit. RT-PCR was performed to amplify group A rotavirus, most commonly pathogenic to human, using VP4- and VP7-specific primers. The detection rates of immunoassays and RT-PCR were compared. Results: ELISA assay was superior to LA assay and moderately concordant with RT-PCR in detecting rotaviral gastroenteritis. Conclusion: Although RT-PCR is known very sensitive, it does not have significant advantage over immunoassay in detecting rotaviral gastroenteritis.

• Proceedings of the Microbiological Society of Korea Conference
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• 2008.05a
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• pp.171-171
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• 2008

We monitored the occurrence of human enteric viruses in urban rivers by cell culture-PCR and RT-nested PCR. Water samples were collected monthly or semimonthly between May 2002 and March 2003 in four urban tributaries. Enteric viruses were detected by RT-nested PCR and cell culture-PCR based on a combination of Buffalo Green monkey kidney (BGMK) and A549 cell lines, followed by phylogenetic analysis of amplicons. By RT-nested PCR analysis, 45 (77.6%), 32 (55.2%), 32 (55.2%), 26 (44.8%), 12 (20.7%), 2 (3.4%), 4 (6.9%), and 4 (6.9%) of 58 samples showed positive results with adenoviruses, enteroviruses, noroviruses (NV) genogroup I (GI) and II (GII), reoviruses, hepatitis A viruses, rotaviruses and sapoviruses, respectively. Adenoviruses were most often detected and only eight (13.8%) samples were negative for adenoviruses and positive for other enteric viruses in the studied sites. Thirty-one (77.5%) of the 40 samples were positive for infectious adenoviruses and/or enteroviruses based on cell culture-PCR, and the frequency of positive samples grown on A549 and BGMK (65.0%) was higher than that grown on BGMK alone (47.5%). The occurrence of each enteric virus, except reoviruses and hepatitis A viruses was not statistically correlated with the water temperature and levels of fecal coliforms according to Binary logistic regression model. By sequence analysis, most strains of adenoviruses and enteroviruses detected in this study are similar to the causative agent of viral diseases in Korea and most NV GI- and GII-grouped strains were closely related to the reference strains from China and Japan, and GII/4-related strains had similar sequences to strains recognized as a worldwide epidemic outbreak. Our results suggested that monitoring human enteric viruses is necessary to improve microbial quality and cell culture-PCR using the combination of A549 and BGMK cells and the adenovirus detection by PCR could be useful for monitoring viral contamination in the aquatic environment.

• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.723-727
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• 2004

Qualitative and quantitative PCR methods were performed to examine detection and quantitation of epsps inserted into genetically modified soybean (GMS) in processed foods, soy milk, tofu, and biji (soybean curd residue). Using PCR amplification to produce two (121 and 330 bp) epsps in GMS, detection limits of GMS in soy milk, tofu, and biji containing 0.01% GMS were measured. For quantitative detection, test samples containing 1, 3, and 5% GMS were measured by real-time PCR method. Results show real-time PCR method is applicable to detect GMS quantitatively in processed foods.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.468-475
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• 2017

This study is for the consideration of the existence tendency of Kudoa septempunctata in olive flounder. In general, muscle has shown a strong PCR positive reaction in spores containing tissues rather than non-containing tissues. However, blood PCR results showed opposed tendency. In various organs of the tested fish containing spores in muscle tissue, heart had shown positive reaction along with muscle at PCR analysis. Muscle fiber necrosis was observed at the histological observation, and this degeneration was common in both samples. The one sample was the PCR positive muscle containing spore and the other was the PCR positive muscle non-containing spore. Both of muscle tissues indicated a positive reaction at ISH (in-situ hybridization) against K. septempunctata.

• Korean Journal of Veterinary Service
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• v.46 no.2
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• pp.123-135
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• 2023

Feline calicivirus (FCV) is considered the main viral pathogen of feline upper respiratory tract disease (URTD). The frequent mutations of field FCV strains result in the poor diagnostic sensitivity of previously developed molecular diagnostic assays. In this study, a more sensitive real-time reverse transcription-polymerase chain reaction (qRT-PCR) assay was developed for broad detection of currently circulating FCVs and comparatively evaluated the diagnostic performance with previously developed qRT-PCR assay using clinical samples collected from Korean cat populations. The developed qRT-PCR assay specifically amplified the FCV p30 gene with a detection limit of below 10 copies/reaction. The assay showed high repeatability and reproducibility, with coefficients of intra-assay and inter-assay variation of less than 2%. Based on the clinical evaluation using 94 clinical samples obtained from URTD-suspected cats, the detection rate of FCV by the developed qRT-PCR assay was 47.9%, which was higher than that of the previous qRT-PCR assay (43.6%). The prevalence of FCV determined by the new qRT-PCR assay in this study was much higher than those of previous Korean studies determined by conventional RT-PCR assays. Due to the high sensitivity, specificity, and accuracy, the new qRT-PCR assay developed in this study will serve as a promising tool for etiological and epidemiological studies of FCV circulating in Korea. Furthermore, the prevalence data obtained in this study will contribute to expanding knowledge about the epidemiology of FCV in Korea.