• Journal of Environmental Science International
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• v.1 no.2
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• pp.99-103
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• 1992

The bacteriophages lytic for Vibrio furnissi, Vibrio furniulis and Vibrio parahemolyticus were isolated from fish gills and shellfish. Nucleic acid of bacteriophage was prepared and restriction endonuclease profile was compared. All isolates contained deoxyribonucleic acid. V. fumissi bacteriophage from fish gills showed 2 bands with Bgl II, 1 with Pst, 3 with Hind III, 1 with Bm HI and 2 with EcoR I. V Puuialis phage represented 7 fragments with Bgl II, 1 with Pst, 4 with Hind III, and 2 with EcoR I. V parhemolyticn produced 13 sites with Hind III and 4 sites with EcoR I. The fragment types were varied depending on the phage isolation. All three phages were digested with Hind III and EcoR I with different sizes. V furnissi phage were digested with 5 different restriction enzymes. Key words: Bacteriophage, Vibrio furnissi, Vibrio fluvialis, Vibrio pnrahemolyticus, Deoxyribonucleic acid, Pst, Bam HI, Hind III, EcoR I, Bgl II.

• Genomics & Informatics
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• v.11 no.3
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• pp.121-128
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• 2013

The introduction of metagenomics into the field of virology has facilitated the exploration of viral communities in various natural habitats. Understanding the viral ecology of a variety of sample types throughout the biosphere is important per se, but it also has potential applications in clinical and diagnostic virology. However, the procedures used by viral metagenomics may produce technical errors, such as amplification bias, while public viral databases are very limited, which may hamper the determination of the viral diversity in samples. This review considers the current state of viral metagenomics, based on examples from Korean viral metagenomic studies-i.e., rice paddy soil, fermented foods, human gut, seawater, and the near-surface atmosphere. Viral metagenomics has become widespread due to various methodological developments, and much attention has been focused on studies that consider the intrinsic role of viruses that interact with their hosts.

• Korean Journal of Veterinary Research
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• v.58 no.1
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• pp.39-43
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• 2018

The efficacy of using a bacteriophage (phage) to control Flavobacterium psychrophilum (F. psychrophilum) infection of ayu (Plecoglossus altivelis altivelis) was evaluated in this study. Intramuscular challenge failed to induce sufficient infection levels; therefore, a newly designed net-scratch challenge method was also used to induce bacterial infection. Administration of phage PFpW-3 in F. psychrophilum-infected ayu showed notable protective effects, increased survival rates and mean times to death. Additionally, the fate of inoculated bacteria and phage in ayu were investigated. Our results suggest that the phage PFpW-3 could be considered an alternative biocontrol agent against F. psychrophilum infections in ayu culture.

• Journal of the Korean Magnetic Resonance Society
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• v.25 no.3
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• pp.39-44
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• 2021

The CRISPR-Cas system provides adaptive immunity for bacteria and archaea against invading phages and foreign plasmids. In the Class 1 CRISPR-Cas system, multi-subunit Cas proteins assemble with crRNA to bind to DNA targets. To disarm the bacterial defense system, bacteriophages evolved anti-CRISPR (Acr) proteins that actively inhibit the host CRISPR-Cas function. Here we report the backbone resonance assignments of AcrIF7 protein that inhibits the type I-F CRISPR-Cas system of Pseudomonas aeruginosa using triple-resonance nuclear magnetic resonance spectroscopy. We employed various computational methods to predict the structure and binding interface of AcrIF7, and assessed the model with experimental data. AcrIF7 binds to Cas8f protein via flexible loop regions to inhibit target DNA binding, suggesting that conformational heterogeneity is important for the Cas-Acr interaction.

• Korean Journal of Food Science and Technology
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• v.53 no.3
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• pp.348-355
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• 2021

Bacteriophages (phages) are known determinants of kimchi microbial ecology. Lactobacillus plantarum is related to kimchi over-acidification during the late stages of kimchi fermentation. A phage infecting Lac. plantarum was isolated from kimchi and characterized. The phage population for kimchi in a market was 2.3 log particles/mL, which corresponded to 32% of the bacterial population on a log scale. The isolated phage was designated as ΦLP12116. ΦLP12116 which belonged to the Siphoviridae family and has a very narrow host range, infecting only Lac. plantarum. The phage was stable at a lactic acid concentration of 1.0% and pH 4.0 at 4℃, indicating that it could survive in kimchi. In the kimchi extract broth treated by the phage, the growth of Lac. plantarum KCCM 12116 was inhibited by 2.2 log CFU/mL compared to the growth in non-phage-treated broth. Therefore, this study suggests that the growth of Lac. plantarum, which is known as an acid-producing strain during late fermentation in kimchi, may be controlled using the phage.

• Korean journal of applied entomology
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• v.14 no.3 s.24
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• pp.111-131
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• 1975

The study has been carried out to investigate the occurrence, damage, characteristics of the pathogen, environmental conditions affecting the disease outbreak, varietal resistance, forecasting, and chemical control of bacterial leaf blight of rice in Korea since 1964. Bacterial leaf blight of rice became a major disease in Korea since 1960. A correlation was found between the annual increase of epidemics and increase of cultivation area of susceptible varieties, Jinheung, Keumnampung etc. Areal damage within the country showed that the more was at southern province, Jeonnam, Gyeongnam and western coast, and at flooded rice paddy. Yield reduction directly related with the amount of infection on upper leaves at heading stage. Fifty per cent of reduction resulted when the lesion area was more than 60 per cent. Less than 20 per cent of lesion area, however, was not affected so much on yield loss One hundred and six isolates collected from all over the country were classified as 8 strains by using 4 different bacteriophages in 1973. It was, however, only two in 1965. There were some specificities on varietal distributions among the strains such as that the Jinheung attacked mainly by strain A, B, C and I, those attack Kimmaze were A, B, H and I. Most strains were found from Tongil except D and E, whereas Akibare was only variety that attacked by strain E. Low temperature, high humidity, heavy rainfall and insutficient daylight favored the disease epidemics. Especially, typhoon and flooding at heading stage were critical factors. The earlier transplanting the more disease was resulted, and more nitrogen fertilizer application accerelated the diseased development in general. The resistance to the disease varied by growing stage of the sane plants. All of recommended varieties in Korea were susceptible to the disease except Norm No. 6 and Sirogane which moderately resistant. The pathogen, Xanthomonas oryzae, was detectable from extract of healthy seedlings that were grown in the field with an heavy infection previous year. The more bacteriophage in irigation water resulted the more disease outbreak, and the existence of more than 50 bacteriophages in 1ml. of irrigation water were necessary to initiate the disease out break. The curves representing occurrence of bacteriophages and disease outbreak were similar with 15 days interval. The survey of bacteriophage occurrence can be utilized in forecasting of the disease two weeks ahead of disease outbreak. Three applications of chemicals, Phenazin and Sangkel, in weekly intervals at the early satage of out-break depressed the symptom development, and increased yield by 20per cent. Proper period for the chemical application was just before the number of bacteriophage reaches 50 in 1ml. of irrigation water.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.176-181
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• 2011

Cronobacter sakazakii and Salmonella enterica Typhimurium are hazardous pathogens, especially for ready-toeat foods. For control of pathogens, the virulent bacteriophages were isolated, identified, and applied to infant formula milk and vegetable juice. The phages were isolated from swine feces and identified by morphology and molecular characteristics. ES2 phage for C. sakazakii and ST2 phage for S enterica Typhimurium were identified as Myoviridae and Siphoviridae, respectively. Their burst sizes were $52{\pm}5PFU/cell$ for ES2 phage and $21{\pm}3PFU/cell$ for ST2 phage after latent period of 30-40 minutes. ST2 phage showed higher heat stability at $60^{\circ}C$ than ES2 phage. ES2 phage held the growth of C. sakazakii untill 6 hr afterwhich the number decreased when applied to the infant formula milk and vegetable juice. ST2 phage also showed growth inhibition so that the number of S. enterica Typhimurium decreased. Therefore, virulent bacteriophages might be an agent for the growth inhibition of C. sakazakii and S. enterica Typhimurium in such the ready-to-eat foods.

• Journal of Applied Biological Chemistry
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• v.59 no.4
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• pp.351-356
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• 2016

Bacterial blotch caused by Pseudomonas tolaasii is one of the major diseases of oyster mushroom, Pleurotus ostreatus. Application of bacteriophages is a very useful tool to decrease the density of pathogens and it has been successful to making disease-free cultivation area, known as phage therapy. Effect of phages on pathogen sterilization is very limited to the specific host strains. Minor variations of the host strains may cause changes in phage sensitivity. The phage-resistant strains of P. tolaasii were isolated and their pathogenic characters were investigated to improve the effectiveness of phage therapy. In the phylogenetic analysis, both phage-resistant strains and the corresponding host strains were identical based on the sequence comparison of 16S rRNA genes. The pathogenic characters, such as hemolytic activity and brown blotch formation, were measured on the phage-resistant strains and no correlation between phage-resistance and pathogenic characters was observed. Nevertheless, pathogenic characters were sometimes changed in the phage-resistant strains depending on the host strains. In order to make the phage therapy successful, the bacteriophages having a wide host range should be isolated.

• Preventive Nutrition and Food Science
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• v.14 no.2
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• pp.162-167
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• 2009

Various fermented foods were screened in search of food-grade bacteria that produce bacteriocins active against Gram-negative pathogens. An isolate from a mold-ripened cheese presented antibacterial activity against Gram-positive and Gram-negative bacteria. The most active isolate was identified as Lactobacillus casei by a biochemical method, ribotyping, and membrane lipid analysis, and was designated as OSY-LB6A. The cell extracts of the isolate showed inhibition against Escherichia coli p220, E. coli O157, Salmonella enerica serovar Enteritidis, Salmonella Typhimurium, and Listeria monocytogenes. The antibacterial nature of the cell extract from the isolate was confirmed by eliminating the inhibitory effects of acid, hydrogen peroxide, and lytic bacteriophages. The culture supernatant and cell extract retained antibacterial activity after heating at $60{\sim}100^{\circ}C$ for $10{\sim}20$ min. The activity of the cell extract from Lb. casei was eliminated by pronase and lipase. Finally, the cell extract showed a bactericidal mode of action against E. coli in phosphate buffer solution, but it was bacteriostatic in broth medium and food extracts.

• Journal of Microbiology and Biotechnology
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• v.27 no.12
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• pp.2151-2155
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• 2017

Bacteriophages have gained substantial attention as biocontrol and biorecognition agents, substituting antibodies. In this study, a Salmonella Enteritidis-specific bacteriophage, KFS-SE1, was isolated, identified, and characterized. This Siphoviridae phage infects S. Enteritidis with high specificity. This phage is highly stable under various pH (5-11), temperature ($4-60^{\circ}C$), and organic solvent conditions. The KFS-SE1 genome consisted of 59,715 bp with 73 predicted open reading frames and 57.14% GC content; it had a complete set of genes required for phage reconstruction. Comparative phylogenetic analysis of KFS-SE1 revealed that it was very similar to the other Salmonella phages in the Siphoviridae family. These characteristics suggest that KFS-SE1 with its high specificity and host lysis activity toward S. Enteritidis may have various potential applications.