• Genomics & Informatics
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• v.14 no.3
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• pp.104-111
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• 2016

Zika virus (ZIKV) is a mosquito borne pathogen, belongs to Flaviviridae family having a positive-sense single-stranded RNA genome, currently known for causing large epidemics in Brazil. Its infection can cause microcephaly, a serious birth defect during pregnancy. The recent outbreak of ZIKV in February 2016 in Brazil realized it as a major health risk, demands an enhanced surveillance and a need to develop novel drugs against ZIKV. Amodiaquine, prochlorperazine, quinacrine, and berberine are few promising drugs approved by Food and Drug Administration against dengue virus which also belong to Flaviviridae family. In this study, we performed molecular docking analysis of these drugs against nonstructural 3 (NS3) protein of ZIKV. The protease activity of NS3 is necessary for viral replication and its prohibition could be considered as a strategy for treatment of ZIKV infection. Amongst these four drugs, berberine has shown highest binding affinity of -5.8 kcal/mol and it is binding around the active site region of the receptor. Based on the properties of berberine, more similar compounds were retrieved from ZINC database and a structure-based virtual screening was carried out by AutoDock Vina in PyRx 0.8. Best 10 novel drug-like compounds were identified and amongst them ZINC53047591 (2-(benzylsulfanyl)-3-cyclohexyl-3H-spiro[benzo[h]quinazoline-5,1'-cyclopentan]-4(6H)-one) was found to interact with NS3 protein with binding energy of -7.1 kcal/mol and formed H-bonds with Ser135 and Asn152 amino acid residues. Observations made in this study may extend an assuring platform for developing anti-viral competitive inhibitors against ZIKV infection.

• Korean Journal of Microbiology
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• v.54 no.1
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• pp.31-37
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• 2018

Campylobacter jejuni is an important food-borne pathogen causing gastroenteritis in human. We isolated 208 strains of Campylobacter jejuni from 430 diarrhea patients and food employees with 17 food-poisoning outbreaks between 2014 and 2016 in Gyeonggi area. The strains were tested for genetic relationship and the genotype distribution using PFGE and multiplex-PCR typing. Among the 47 Penner-serotypes known for C. jejuni, it was identified as a genotype consisting of 35 genotypes by multiplex-PCR typing and represented 7 genotypes (HS2, HS4A, HS8, HS15, HS29, HS41, and HS53) in the selected strain. From the PFGE analysis of 11 food-poisoning outbreaks, 5 group of PFGE profile were obtained, and genetic similarity in these clusters ranged from 61.8 to 66.6%. This study examines the genetic diversity of C. jejuni that have been separated in the Gyeonggi area through various genetic analysis methods and identifies the correlation between strains in patients who have been infected with the disease in the future.

• Korean Journal of Food Science and Technology
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• v.43 no.5
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• pp.618-623
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• 2011

Escherichia coli O157:H7 has been considered as a significant food-borne pathogen since its role in causing hemorrhagic colitis and hemolytic uremic syndrome in humans was recognized. In this study, we developed an immunochromatography (ICG) assay for the detection of E. coli O157:H7. E. coli O157:H7 monoclonal antibody (EC MAb) and colloidal gold were conjugated and its specificity was determined by the ICG treated with EC MAb and antimouse IgG at test and control lines, respectively. The detection limit of the ICG was $1{\times}10^5$ CFU/mL, and no crossreactivity was observed to other E. coli strains and major food-borne pathogens. To determine the minimum enrichment time for the ICG, meats and sprouts were inoculated with $1{\times}10$ CFU/100 ${\mu}L$ of E. coli O157:H7. After enrichment time of 10 and 2 h for meats and sprouts, respectively, up to $1{\times}10$ CFU/100 ${\mu}L$ of E. coli O157:H7 could be detected by ICG.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.6
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• pp.437-442
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• 2014

Foodborne illness due to the consumption of contaminated raw strawberries is a continuing food safety concern. This study investigated and evaluated contamination levels of bacteria on strawberries at farms stage to evaluate potential hazards associated with fresh strawberries. A total of 315 samples, 105 samples from 5 sampling sites (A to E) of 21 farms and 210 samples from 1 sampling site of 6 farms, was collected every month for four months and analyzed to enumerate aerobic bacterial counts, Coliforms/E. coli, Bacillus cereus and Staphylococcus aureus. In addition, the prevalence study of five pathogens (S. aureus, E. coli, E. coli O157:H7, Salmonella spp. and Listeria monocytogenes) was performed on each sample. Aerobic bacterial counts ranged from 0.48 to 6.36 Log CFU/g, with the highest bacterial cell counts recorded for D and E sites. Coliforms were detected in 71 samples (22.5%) with a minimum of 0.48 cfu/g and a maximum of more than 4 Log CFU/g. B. cereus was detected in 98 samples (31.1%) among total samples analyzed. S. aureus was detected in 2 samples with a minimum of 0.48 Log CFU/g and a maximum of 1.38 Log CFU/g. E. coli, E. coli O157:H7, Salmonella spp. and L. monocytogenes were not isolated from any of the samples. The microbial contamination levels of strawberries determined in this study may be used as the fundamental data for microbiological risk assessment.

• Journal of Life Science
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• v.33 no.10
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• pp.842-850
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• 2023

Pyrrolnitrin, pyrrolomycin, and pyoluteorin are functional halogenated phenylpyrrole derivatives (HPDs) derived from microorganisms with diverse antimicrobial activities. Pyrrolnitrin is a secondary metabolite produced from L-tryptophan through four-step reactions in Pseudomonas fluorescens, Burkholderia cepacia, Serratia plymuthica, etc. It is currently used for the treatment of superficial dermatophytic fungal infections, has high antagonistic activities against soil-borne and foliar fungal infections, and has many industrial applications. Since pyrrolnitrin is easily decomposed by light, it is difficult to widely use it outdoors. As an alternative, fludioxonil, a synthetically produced non-systemic surface fungicide that is structurally similar and has excellent light stability, has been commercialized for seed and foliar treatment of plants. However, due to its high toxicity to aquatic organisms and adverse effects in human cell lines, many countries have established maximum residue levels and strictly control its levels. Pyrrolomycin and pyoluteorin, which have antibiotic/antibiofilm activity against Gram-positive bacteria and high anti-oomycete activity against the plant pathogen Pythium ultimum, respectively, were isolated and identified from microorganisms. This review summarizes the biosynthesis and production of natural pyrrolnitrin derived from bacteria and the characteristics of synthetic fludioxonil and other natural phenylpyrrole derivatives among the HPDs. We expect that a plethora of highly effective, novel HPDs that are safe for humans and environments will be developed through the generation of an HPD library by microbial biosynthesis and chemical synthesis.

• Journal of Life Science
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• v.34 no.1
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• pp.48-58
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• 2024

Salmonella is a common food-borne intracellular bacterial pathogen that has triggered significant public health concerns. Salmonella hosts' genetic factors play a pivotal role in determining their susceptibility to the pathogen. Cysteine-rich intestinal protein 1 (CRIP1), a member of LIM/double zinc finger protein family, is widely expressed in humans, such as in the lungs, spleen, and especially the gut. Recently, CRIP1 has been reported as a key marker of several immune disorders; however, the effect of CRIP1 on bacterial infection remains unknown. We aimed to elucidate the relationship between Salmonella infection and CRIP1 gene deficiency, as Salmonella spp. is known to invade the Peyer's patches of the small intestine, where CRIP1 is highly expressed. We found that CRIP1-deficient conditions could not alter the characteristics of bone marrow-derived myeloid cells in terms of phagocytosis on macrophages and the activation of costimulatory molecules on dendritic cells using ex vivo differentiation. Moreover, flow cytometry data showed comparable levels of MHCII⁺CD11b⁺CD11c⁺ dendritic cells and MHCII⁺F4/80⁺CD11b⁺ macrophages between WT and CRIP1 knockout (KO) mice. Interestingly, the basal population of monocytes in the spleen and neutrophils in MLNs is more abundant in a steady state of CRIP1 KO mice than WT mice. Here, we demonstrated that the CRIP1 genetic factor plays dispensable roles in host susceptibility to Salmonella Typhimurium infections and the activation of myeloid cells. In addition, differential immune cell populations without antigen exposure in CRIP1 KO mice suggest that the regulation of CRIP1 expression may be a novel immunotherapeutic approach to various infectious diseases.

• Journal of the Korean Chemical Society
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• v.54 no.2
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• pp.215-221
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• 2010

Salmonella is an important food-and water-borne pathogen associated with acute gastrointestinal illnesses around the world. The most common serotypes isolated from humans are Salmonella enterica serotype Typhimurium (S. Typhimurium) and S. Enteritidis. Traditional detection methods for Salmonella are based on cultures using selective media and characterization of suspicious colonies by biochemical and serological tests. These methods are generally time-consuming and not so highly sensitive. Recently, the Loop Mediated Isothermal Amplification and real-time PCR has been used as a highly sensitive, specific, and rapid test for the presence of pathogenic bacteria. In this study, a LAMP and real-time PCR was used to detect S. Typhimurium and S. Enteritidis. We selected target genes, which were the in invA and a randomly cloned sequence specific for the genus Salmonella. With LAMP and real-time PCR, random sequence was detected from Salmonella spp, invA were detected from all strain of S. Typhimurium and S. Enteritidis. This assay indicate that the specificity, sensitivity and rapid of the LAMP and real-time PCR make them potentially valuable tools for detection of S. Typhimurium and S. Enteritidis.

• Food Science of Animal Resources
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• v.28 no.5
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• pp.555-561
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• 2008

Ninety-nine samples of powdered infant formula in a market were collected from the local market and their contaminations for total aerobic bacteria, coliform, FAO/WHO Category A, B, and C pathogens were analyzed. Total aerobic bacteria were detected in 92 of 99 samples (93%) at levels of $1.83{\pm}0.68\;Log\;MPN/g$. These levels were below legal levels specified for infant formulas except for one sample detected by 4.5 Log CFU/g. Coliform was detected in 12 of 99 samples (12%) at levels of $1.26{\pm}1.03\;Log\;MPN/g$ whereas non-detection was required according to the specification of coliform in infant formulas. Escherichia coli was detected in 1 of 99 samples by 0.48 Log MPN/g. Salmonella and Enterobacter sakazakii among Category A weren't detected in all the samples. Enterobacteriaceae, Category B group, were detected in 25 samples of total 99 samples (25%) by $0.83{\pm}1.37\;Log\;MPN/g$. Enterobacteriaceae identified by API 20E were Escherichia vulneris, Es. hermannii, Pantoea spp., Citrobacter koseri, Klebsiella pneumoniae, En. cloaceae. Bacillus cereus among Category C was highly detected in 29 of 99 samples (29%) at levels of $0.69{\pm}0.32\;Log\;MPN/g$ with the most probable number count method, which were below legal levels for the specification of B. cereus in infant formulas. Clostridium perfringens, E. coli O157, Staphyloccus aureus, Listeria monocytogenes, Yersinia enterocolitica, and Campylobacter jejuni/coli were not detected. Contamination level of major pathogens was low and falls within the range of specification of infant formulas. However, Enterobacteriaceae and B.cereus showed the high prevalence and some Enterobacteriaceae causing disease were detected. Therefore, it is necessary to monitor the potential pathogens continually and reduce them to improve the microbial quality of non-sterilized powdered infant formulas.

• Korean Journal of Medicinal Crop Science
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• v.13 no.3
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• pp.93-100
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• 2005

This research was performed to investigate the possibilities of industrial usage of camellia (Camellia japonica L.) by examining the antioxidant and antimicrobial effects of methanol extract with different sections. Content of total phenolics, DPPH radical scavenging activities and antibacterial activity of young leaf, mature leaf, flower bud, flower, bark, and seed of camellia were compared in vitro experimental models. Total phenolics was contained the higher in young leaf (74.62 mg), flower bud (65.02 mg) and flower (62.42 mg) but less than 20.95 mg per 100 g of dry weight in other parts of Camellia japonica L. And effects of antioxidant measured by DPPH radical scavenger activity ($RC_{50}$, reduce concentration 50%), was shown higher $7.16{\sim}18.14\;{\mu}g/m{\ell}$ in methanol extract of young leaf, flower bud and flower than $61.23\;{\mu}g/m{\ell}$ of BHT as a chemical oxidant. Also, the antimicrobial activity of Camellia japonica L. extracts determined using a paper disc method against food-borne pathogen and food spoilage bacteria, the young leaves extracts showed the most active antimicrobial activity against 7 kinds of harmful microorganisms. Flower bud extracts showed the highest antibacterial activity against P. aeruginosa and Enterobacter spp. C1036. In addition, the minimum inhibitory concentration (MIC) of young leaf extract against B. subtillis,S. fradiae,S. aureus,E. coli,P. aeruginosa, Enterobacter spp. C1036, and S. typhimurium were revealed 1 to 15 ${\mu}g/m{\ell}$. As a result, antimicrobial activity of camellia extracts was shown higher gram positive bacteria than gram negative bacteria.

• Journal of Food Hygiene and Safety
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• v.28 no.4
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• pp.324-329
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• 2013

This study investigated and evaluated contamination levels of bacteria on tomatoes at farms stage to evaluate potential hazards associated with fresh tomatoes. A total of 170 samples, 90 samples from 5 sampling sites from 18 farms and 80 samples from 1 sampling site from 4 farms every month for four months, were analyzed to enumerate aerobic bacterial counts, coliforms, E. coli, Bacillus cereus, Staphylococcus aureus, Escherichia coli, E. coli O157:H7, Salmonella spp., and Listeria monocytogenes. Aerobic bacterial counts ranged from 0.48 to 6.15 Log CFU/g, with the lowest and the highest bacterial cell counts recorded for A site and E site, respectively. Thirty five percent of the samples from the E site contained more than 2 Log CFU/g. Six samples (6.6%) of 90 samples contained B. cereus less than 1 Log CFU/g. In addition, the contamination level of indicator bacteria and B. cereus in tomatoes were higher on March than on April, May and June (P < 0.05). S. aureus, E. coli, E. coli O157:H7, Salmonella spp. and L. monocytogenes were not detected in the tomato samples. The microbial contamination levels of tomatoes determined in this study may be used as the data for microbiological risk assessment.