• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1063-1066
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• 2004

The rpoS gene product is a global transcriptional factor, which is involved in bacterial survival under various stress conditions. An rpoS-homologous gene was cloned from a septicemia-causing pathogenic Vibrio vulnificus. Introduction of this gene as a multicopy plasmid into various E. coli strains displayed functional complementation, for examples, increased survivability of an rpoS-defective E. coli cell and induction of known $\delta^S$-dependent, stress-responding promoters of E. coli genes.

• Applied Science and Convergence Technology
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• v.25 no.3
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• pp.61-65
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• 2016

Here, the rapid detection of Salmonella typhimurium by a portable surface plasmon resonance (SPR) biosensor in which the beam from a diode laser is modulated by a rotating mirror is reported. Using this system, immunoassay based on lipopolysaccharides (LPS)-specific monoclonal anti-Salmonella antibody was performed. For the purpose of orientation-controlled immobilization of antibodies on the SPR chip surface, the cysteine-mediated immobilization method, which is based on interaction between a gold surface and a thiol group (-SH) of cysteine, was adopted. As a result, using the portable SPR-based immunoassay, we detected S. typhimurium in the range from 10^7 CFU/mL to 10^9 CFU/mL within 1 hour. The results indicate that the portable SPR system could be potentially applied for general laboratory detection as well as on-site monitoring of foodborne, clinical, and environmental agents of interest.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1368-1371
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• 2008

In this study, 50 rump samples of raw beef obtained from local Korean supermarkets were analyzed to survey microbial distributions. As results, mesophilic microorganisms ranged from $(1.4{\pm}0.01){\times}10^2$ to $(1.6{\pm}0.05){\times}10^5\;CFU/g$, and total coliforms ranged from 0 to $(1.3{\pm}0.04){\times}10^4\;CFU/g$. Major foodborne pathogens, including Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella spp., were not found among the samples. However, Staphylococcus aureus was isolated with 4% frequency. Other isolated microorganisms included Enterobacter amnigenus (4%), Enterobacter cloacae (24%), E. coli (24%), Listeria innocua (8%), Staphylococcus saprophyticus (56%), Staphylococcus xylosus (10%), and Staphylococcus warneri (8%).

• Journal of Microbiology and Biotechnology
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• v.25 no.1
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• pp.98-108
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• 2015

Staphylococcus aureus is an important foodborne pathogen that causes diverse diseases ranging from minor infections to life-threatening conditions in humans and animals. To further understand its pathogenesis, the genome of the strain S. aureus FORC_001 was isolated from a contaminated food. Its genome consists of 2,886,017 bp double-stranded DNA with a GC content of 32.8%. It is predicted to contain 2,728 open reading frames, 57 tRNAs, and 6 rRNA operons, including 1 additional 5S rRNA gene. Comparative phylogenetic tree analysis of 40 complete S. aureus genome sequences using average nucleotide identity (ANI) revealed that strain FORC_001 belonged to Group I. The closest phylogenetic match was S. aureus MRSA252, according to a whole-genome ANI (99.87%), suggesting that they might share a common ancestor. Comparative genome analysis of FORC_001 and MRSA252 revealed two non-homologous regions: Regions I and II. The presence of various antibiotic resistance genes, including the SCCmec cluster in Region I of MRSA252, suggests that this strain might have acquired the SCCmec cluster to adapt to specific environments containing methicillin. Region II of both genomes contains prophage regions but their DNA sequence identity is very low, suggesting that the prophages might differ. This is the first report of the complete genome sequence of S. aureus isolated from a real foodborne outbreak in South Korea. This report would be helpful to extend our understanding about the genome, general characteristics, and virulence factors of S. aureus for further studies of pathogenesis, rapid detection, and epidemiological investigation in foodborne outbreak.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1753-1762
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• 2017

Sea cucumber (Apostichopus japonicus) is a popular seafood source in Asia, including South Korea, and its consumption has recently increased with recognition of its medicinal properties. However, because raw sea cucumber contains various microbes, its ingestion can cause foodborne illness. Therefore, analysis of the microbiota in the whole body of sea cucumber can extend our understanding of foodborne illness caused by microorganisms and help to better manage products. We collected 40 sea cucumbers from four different sites in August and November, which are known as the maximum production areas in Korea. The microbiota was analyzed by an Illumina MiSeq system, and bacterial amounts were quantified by real-time PCR. The diversity and bacterial amounts in sea cucumber were higher in August than in November. Alpha-, Beta-, and Gammaproteobacteria were common dominant classes in all samples. However, the microbiota composition differed according to sampling time and site. Staphylococcus warneri and Propionibacterium acnes were commonly detected potential pathogens in August and November samples, respectively. The effect of experimental Vibrio parahaemolyticus infection on the indigenous microbiota of sea cucumber was analyzed at different temperatures, revealing clear alterations of Psychrobacter and Moraxella; thus, these shifts can be used as indicators for monitoring infection of sea cucumber. Although further studies are needed to clarify and understand the virulence and mechanisms of the identified pathogens of sea cucumber, our study provides a valuable reference for determining the potential of foodborne illness caused by sea cucumber ingestion and to develop monitoring strategies of products using microbiota information.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1341-1345
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• 2016

Gallic acid was isolated from Caesalpinia mimosoides Lamk and the structure s identified based on spectroscopic analysis and comparison with authentic compound. In this study we compared the ability of natural gallic acid (nGA) and commercial gallic acid (cGA) to inhibit the proliferation of cholangiocarcinoma cell lines (M213, M214) and foodborne pathogenic bacteria (Salmonella spp. and Plesiomonas shigelloides). Both nGA and cGA had the same inhibitory effects on cell proliferation by inducing apoptosis of cholangiocarcinoma cell lines. In addition, nGA inhibited growth of foodborne pathogenic bacteria in the same manner as cGA. Our results suggest that nGA from Caesalpinia mimosoides Lamk is a potential anticancer and antibacterial compound. However, in vivo studies are needed to elucidate the specific mechanisms involved.

• Bulletin of Food Technology
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• v.18 no.3
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• pp.98-104
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• 2005

본 학회는 92년의 역사를 가지고 있는 대표적인 식품위생학회로서 특히 microbial hazard인 foodborne pathogen에 대한 다양한 연구가 보고되는 학회이기도 하다. 올해의 symposium은 Foodbioterrorism에 대한 내용, Yeast and molds에 대한 집중연구와 새로운 분석기술로 각광을 받고 있는 microarray technology에 대하여 중점적인 발표가 있었다. 내년도 International Association for Food Protection은 Canada의 calgary에서 개최될 예정이며, 식품위생 분야에서 microbial hazard에 대해 상당한 권위를 가지고 있는 학회로 학회지인 Journal of Food Protection도 impact factor가 2.154로 applied microbiology 분야에서 매우 높고, 내년도 학술발표를 위한 초록마감은 내년도 1월초 정도이다.

• 한국환경농학회:학술대회논문집
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• 2009.07a
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• pp.157-168
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• 2009

Frequent outbreaks of foodborne illness have been increasing the awareness of agro-food safety. Conventional methods for pathogen detection and identification are labor.intensive and take days to complete. The increasing use of rapid food safety testing is receiving more and more attention. The major reason for this trend is that the food industry requires quick and accurate results. The rapid detection of contaminants in food is critical for ensuring the safety of consumers. Recent advances in technology make detection and identification faster, more sensitive and more specific than traditional method. In this paper, technology trends and recent developments in rapid methods for agro-food safety are discussed.

• Journal of Microbiology
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• v.41 no.2
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• pp.144-147
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• 2003

Listeria monocytogenes is a pathogen of major concern to the food industry and the potential cause of severe infections such as listeriosis. Early detection of this foodborne pathogen is important in order to eliminate its potential hazards. So, immunomagnetic separation (IMS) has been suggested as a means of reducing the total analysis time and for improving the sensitivity of detection. Atomic force microscopy (AFM) has been used for measuring the topographic properties of sample surfaces at nanometer scale. In this study, we used AFM to confirm both the sensitivity and the specificity of IMS. Regarding AFM analysis, the length and the width of the bacteria, which were in agreement with literature values, were found to be 2.993 $\mu\textrm{m}$ and 0.837 $\mu\textrm{m}$, respectively. As a result, AFM helped us both characterize and measure the bacterial and bead structures.

• Bulletin of the Korean Chemical Society
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• v.27 no.4
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• pp.479-483
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• 2006

We developed a microfluidic immunoassay platform for the detection of various analytes such as bacterial pathogen by packing antibody-immobilized glass beads in spatially-isolated microchambers on a microfluidic device. Primary amines of antibody were covalently conjugated to carboxyl-terminated glass beads previously treated with aminosilane followed by glutaraldehyde. Through this covalent binding, up to 905 $\mu$g immunoglobulin G (IgG) per gram of glass beads was immobilized. For application, glass beads attaching antibody specific to Escherichia coli O157:H7, a foodborne pathogen, were packed into a microfluidic device and used for the detection of the serotype. This prototype immunoassay device can be used for the simultaneous detection of multiple analytes by sequentially packing different-sized glass beads attaching different antibody in discrete microchambers on a single microfluidic device.