• Korean Journal of Medicinal Crop Science
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• v.16 no.2
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• pp.112-117
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• 2008

This experiment was carried out to obtain the basic information on processing for product of high quality goods in Artemisia capillaris. We investigated antioxidant and antimicrobial activities by harvesting date and plant parts in Artemisia capillaris. Contents of total polyphenol compounds and flavonoids were the highest in leaf, followed by capitulum and stem. Leaf on June 30 contained 76.7 mg/g DW total phenolic compounds and 78.2 mg/g DW flavonoids. As $RC_{50}$ value, that was, the concentration of sample required for 50% reduction of DPPH (2,2-diphenyl-l-picrylhydrazyl) absorbance, was very low as $5.42\;{\mu}g$ in leaf on June 30, antioxidant activity was the highest. In addition, $RC_{50}$ of BHA, BHT and ${\alpha}-tocopherol$ were $3.09\;{\mu}g$, $24.30{\mu}g$ and $2.87{\mu}g$, respectively. And capitulum had antimicrobial activities against Bacillus subtilis, Staphylococcus aureus, Enterobacter aerogenes, Citrobacter freundii, Vibrio vulnificus, Pseudomonas aeruginosa, Saccharomyces cerevisiae. By the way, leaf and stem rarely had antimicrobial activity. Antimicrobial activities of capitulum according to harvesting date were very various. Capitulum on August 30 had the highest antimicrobial activities against Bacillus subtilis, Staphylococcus aureus, Vibrio vulnificus, Saccharomyces cerevisiae and on July 30 against Enterobacter aerogenes, Citrobacter freundii, Pseudomonas aeruginosa.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.374-383
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• 2021

Rhizoctonia solani is one of the major pathogens that cause sheath blight disease in rice. Sheath blight is one of the most difficult diseases to control. Biological control (with the use of rhizobacteria) is one of the ways to control this disease. Plant Growth Promoting Rhizobacteria (PGPR) is a rhizosphere bacterium that can be used to enhance plant growth. The composition of the rhizobacteria in organic and nonorganic soil is affected by the chemical characteristics of the soil - which influences plant physiology and root exudation patterns. This study aimed to obtain a species of rhizobacteria which shows PGPR activity, from organic and nonorganic rice fields and test their capability to suppress R. solani growth. Out of 23 isolates screened for PGPR activity, the following isolates showed high PGPR activity and were selected for in vitro antagonistic activity testing against R. solani: ISO6, ISO11, ISO15, ISN2, ISN3, and ISN7, The six isolates produced 43,42-75,23 ppm of IAA, possessed phosphorus solubilization capability, and chitinase-producing activity. ISO6 (54.88%) and ISN7 (83.33%) displayed high inhibition capacities against R. solani, in vitro. ISO6 and ISN7 inhibited the growth of R. solani lesions on rice leaves by 89% and 100% (without lesion), respectively, after 7 days of incubation. Analysis of their 16S rRNA sequences revealed that the ISO6 isolate was Citrobacter freundii and ISN7 isolate was Pseudomonas aeruginosa.

• Microbiology and Biotechnology Letters
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• v.24 no.1
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• pp.44-49
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• 1996

By using the ${\beta}$-tyrosinase of Citrobacter freundii KCT2006, which was cloned and overexpressed in Escherichia coli, 3,4-dihydroxy phenyl-L-alanine (L-DOPA) was synthesized efficiently from pyrocatechol, sodium pyruvate, and ammonium acetate. Optimal temperature and pH for the reaction were determined to be about 18$^{\circ}C$ and 8.5, respectively. The effects of substrate concentrations were also examined at different concentrations of ammonium acetate, sodium pyruvate, and pyrocatechol. Ammoniumacetate and sodium pyruvate increased the reaction rate until the concentrations reached to 300mM and 50mM, respectively. Although pyrocatechol showed the optimal concentration at 20mM, it was controlled between 20mM and 50mM to avoid the depletion of substrate during the enzymatic synthesis. Meanwhile the synthetic rate was improved about 20% when ethanol was included in the reaction solution. Based on above results, a reaction medium for the productin of L-DOPA was prepared and incubated with 1 unit/ml of ${\beta}$-tyrosinase. Pyrocatechol and sodium pyruvate was added to the reaction solutin intermittently to avoid the substrate depletion during the enzymatic reaction. After 24 hour of reaction, 31.6g/l of L-DOPA was accumulated in the reaction solution as soluble and precipitated ones and the conversion yield was about 85.2%.

• Journal of Marine Life Science
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• v.1 no.1
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• pp.18-24
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• 2016

Since April 2012, doctor fish in the breeding tank and in the quarantine tank in Hanwha Aquaplanet Yeosu Aquarium have been dying, accompanied by diffuse bleeding around the mouth, in the chin, and at the bottom of the abdomen. In this study, the cause of death would be examined through the bacteriological study of doctor fish and the rearing water quality in the aquarium. The water quality and the bacterial counts of the rearing water in the exhibit tank and in the quarantine tank were analyzed once a week, starting from August to November 2014. Water quality was measured based on the following data: temperature was in the range of 24.5~26.8℃, pH at 6.77~7.94, DO at 6.15~8.61 ppm, ammonia at 0~0.93 ppm, nitrite at 0.009~0.075 ppm, and nitrate at 1.1~40.9 ppm. Studies revealed that the differences in these water quality factors were not related to the death of doctor fish. Bacterial counts in the rearing waters of Garra rufa slightly increased to 10³~10⁴ CFU/ml, just before the death of the doctor fish. Twelve strains of bacteria were isolated from the dead fish and rearing waters. The isolates were identified as Aeromonas veronii, Citrobacter freundii, Pseudorhodoferax aquiterrae, Shewanella putrefaciens, and Vibrio anguillarum on the basis of 16S rRNA gene sequences. The most dominant species was C. freundii, which showed medium sensitivity to florfenicol and norfloxacin, and was resistant to amoxacillin, doxycycline, oxytetracycline, tetracycline, and trimethoprim. Ten isolates were confirmed to be pathogenic to the doctor fish. Doctor fish infected with C. freundii and S. putrefaciens showed high mortality in the experimental groups. These results indicate that the variation in bacterial numbers in the rearing water was related to the death of doctor fish. C. freundii and S. putrefaciens were directly implicated in causing the death of doctor fish in the aquarium.

• Biomedical Science Letters
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• v.16 no.1
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• pp.10-18
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• 2010

The present study was set to develop comprehensive system for assessing the safety of drinking water using PCR-reverse blot hybridization assay (REBA). The REBA developed in this study can detect waterborne pathogens such as Shigella spp., Salmonella spp., Citrobacter spp., Enterobacter spp., Klebsiella spp., Yersinia spp., Mycobacterium spp., Listeria spp. at the genus level, and Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Yersinia enterocolitica, Y. pseudotuberculosis, Mycobacterium avium complex, M. marinum, Enterococcus faecalis, and Staphylococcus aureus at the species level, and E. coli O157:H7 at the strain level.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.277-282
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• 2019

The object of this study is to compare the performance of the 3M Molecular Detection Assay 2 (3M MDA 2) and the Korea Standard Food Codex (KSFC) Method (i.e., isolation media and real-time PCR) in detecting Salmonella Typhimurium and Listeria monocytogenes in traditional Korean foods. Yuk-hwe and Yuk-sashimi (types of raw beef dishes) were artificially inoculated with $10^0-10^4CFU/25g$ of L. monocytogenes and S. Typhimurium. Citrobacter freundii and Listeria innocua were used as competitive microflora. After enrichment, the samples were analyzed using 3M MDA 2 and real-time PCR. All samples inoculated at concentrations of $10^0-10^4CFU/25g$ without competitive microflora were positive for S. Typhimurium and L. monocytogenes, as detected by 3M MDA 2 and Korea Standard Food Codex (KFSC) Method. In addition, part of the samples were positive for the presence of C. freundii and L. innocua. The 3M MDA 2 - Salmonella and Korea Standard Food Codex (KFSC) Method showed similar detection performances in Yuk-hwe and Yuk-sashimi. The 3M MDA 2 method for Salmonella and Listeria, which is a LAMP-based technology, can be used for rapid detection of S. Typhimurium and L. monocytogenes in raw beef. LAMP bioluminescence assays provide results on the subsequent day and are simple to use compared with the Korea Standard Food Codex (KFSC) Method, particularly in terms of DNA preparation.

• Journal of fish pathology
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• v.36 no.2
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• pp.239-250
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• 2023

Disease monitoring was conducted to investigate the recent disease occurrence in Japanese eels (Anguilla japonica). Between May 2021 and March 2022, an investigation was conducted on eels from seven farms experiencing mortality. JEECV (Japanese eel endothelial cells-infecting virus) was detected in all examined farms, each exhibiting co-infections with 1 or 2 bacteria, including Edwardsiella anguillarum, E. piscisida, Aeromonas sp., Citrobacter freundii, Lactococcus garviae, or Vibrio sp. From March 2022 to October 2023, monthly periodic inspections were carried out at a farm in Yeonggwang, Jeollanam-do, for a total of 22 times. JEECV was detected in 10 out of 22 times, even when mortality was not recorded. Bacteria such as E. anguillarum, C. freundii, Aeromonas sp., and Vibrio sp. were isolated, but consistent clinical signs of liver abscess and hemorrhagic lesions were only recognized in fish infected with E. anguillarum. Other bacteria were often isolated from apparently healthy fish. In conclusion, mortality in eel farms frequently occurs due to co-infections of JEECV with bacteria rather than JEECV alone. Therefore, to reduce eel mortality, it is crucial to decrease co-infections, with a particular emphasis of JEECV and E. anguillarum.

• Journal of Food Hygiene and Safety
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• v.16 no.2
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• pp.96-102
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• 2001

Bacteriological quality of beef carcass and distributions of pathogens in beef processing environments were investigated to improve the hygienic quality of fresh beef. Total bacterial contamination of carcass surface in slaughtering process and cutting board in cut-meat process showed 10$^{5}$ -10$^{6}$ CFU/$\textrm{cm}^2$ and 10$^{5}$ CFU/$\textrm{cm}^2$ in summer, respectively. The viable bacterial count of cotton glove was similar to that of cutting board during and entire period of year. Microbial contamination of carcass surface, cutting board, cotton glove and deboned meat showed the highest in summer and the lowest in winter during the year. Escherichia coli O157, Pseudomonas aeruginosa, Klebsiella. ornithinolytica, Staphylococcus aureus, E coli, Tatumella. ptyseos, Serratia odorifera, Aero-monas sobria, Enterobacter cloacae and Flavimonas oryzihabitans were isolated from carcass surface during slaughter treatments. S. aureus, Listeria grayi and L. monocytogenes were isolated from cutting board and L. grayi, Erwinia spp. Salmonella app. and S. aureus were isolated from cotton glove in cut-meat process environments. Citrobacter freundii; L. monocytogenes; and S. aureus were isolated from deboned meat.

• The Journal of Internal Korean Medicine
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• v.26 no.3
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• pp.521-532
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• 2005

Objectives & Methods : In order to evaluate the in vitro synergic effects or Eunkyo-san which is a traditional poly-herbal formula that has been used in the treatment of respiratory diseases in oriental medicine, and quinolone antibiotics, rufloxacin (RUFX) and iprofloxacin(CPFX), experimentation was designed to determine minimal inhibitory concentration(MIC), $MIC_{50}\;and\;MIC_{90}$ of single use of quinolones and concomitant treatment with Eunkyo-san against 5 strains of aerobic gram negative bacteria, Escherichia coli, Klebsiella peumoniae, Hemophilus influenzae, Citrobacter freundii and Pseudomonas aeruginosae. Result : In the case of aerobic gram negative bacteria, the MIC, $MIC_{50}\;and\;MIC_{90}$ against Klebsiella peumoniae and Citrobacter freundii significantly decreased in concomitant-treated groups with Eunkyo-san compared to those of single-treated groups of RUFX and CPFX, respectively. However, no significant changes were demonstrated against Echerichia coli, Hemophilus influenzae and Pseudomonas aeruginosae. Conclusion : According to these results, concomitant use of Eunkyo-san against some strains of aerobic gram-negative bacteria dramatically increases in vitro antibacterial activity of RUFX and CPFX, and the increase and selectivity of antibacterial activities against these strains is attributable to Eunkyo-san, and not RUFX or CPFX activity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.684-689
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• 2005

In order to evaluate the in vitro synergic effect of Mahwangyounpae-tang which was a traditional poly-herbal formula has been used in the treatment of respiratory diseases in oriental medicine, and quinolone antibiotics, ciprofloxacin (CPFX), the minimal inhibitory concentration (MIC), $MIC_{50}$ and MIC90 of single use of quinolones and concomitant treatment with Mahwangyounpae-tang against 5 strains of aerobic gram negative bacteria, Escherichia coli, Klebsiella peumoniae, Hemophilus influenzae, Citrobacter freundii and Pseudomonas aeruginosae. The obtained results were as follows : In the case of aerobic gram negative bacteria, the MIC, $MIC_{50}$ and $MIC_{90}$ against Klebsiella peumoniae and Pseudomonas aeruginosae was significantly decreased in concomitant treated groups with Mahwangyounpae-tang compared to those of single treated groups of CPFX, respectively. However, no significant changes were demonstrated against Echerichia coli, Hemophilus influenzae and Citrobacter freundii. According to these results, it is considered as the in vitro antibacterial activity of CPFX was dramatically increased by concomitant use of Mahwangyounpae-tang against some strains of aerobic gram negative bacteria and the increase and selectivity of antibacterial activities against strains were chosen by the selectivity of Mahwangyounpae-tang not CPFX activity.