• Journal of fish pathology
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• v.4 no.2
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• pp.87-94
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• 1991

In the late summer of 1990 and 1991, mass mortality occured among cage-cultured grouper, Epinephelus septemfasciatus in south cost of Korea. The moribund fish didn't feed and became pale or dark chestnut colour and irregularly swimmed due to the loss of equilibrium, finally the diseased fish fell down side away on the bottom or the surface of cage showing the bent of body and died. The diseased fish showed the extensive hemorrahge in brain, the swelling of spleen and bile duct as the specific syptoms of internal organs. So the gill, skin and other organs of the diseased fish were examined for the presence of pathogenic parasites and bacteria. The parasitic Trichodina sp. were detected only from the gill lamella of the diseased fish, but these parasites seemed to be not a direct causative agents that induced the gross mortality of the cultured grouper. because these parasites were also observed in normal grouper, yellowtail, red seabream and rock bream co-cultured with the diseased grouper in same or near cages. In the viral examination, although isolation of the causative agent by the use of estabilshed cell Lines, RTG-2 and CHSE-214, was not succeed, the normal grouper inoculated intramuscularly with the filtered homogenate of the organs of the diseased fish showed the same external and internal signs with the naturally infected grouper. They died within a week. By using the naturally and the artificially infected fishes, electron microscopic observation revealed numerous hexagonal or polygonal particles in the cytoplasm of liver cells. Based on the these results, we suggest that the mass mortality of the cultured grouper would be occurred by the infection of a viral agent.

• Korean Journal of Microbiology
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• v.39 no.1
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• pp.36-39
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• 2003

The rapid and reliable 16S rDNA multiplex polymerase chain reaction (PCR) assay was established to characterize bacterial etiologies of middle ear effusion. These etiologies included Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumonia, which were detected in middle-ear effusion (MEE) samples taken from patient with otitis media. A total of 39 MEE samples were aspirated from 26 patients. DNA was extracted from MEE samples, and PCR was done with DNA extracts by using the common primers, which is localized at C4 region in the 16S rDNA gene of all bacterial species, and species-specific primers: (i) Haemophilus-specific primer, (ii) Moraxella- specific primer, and (iii) Streptococcus-specific primer. Among 39 samples tested, 24 (61.5%) were positive for H. influenzae, 10 (25.6%) were positive for M. catarrhalis, 3(7.7%) were positive for S. pneumonia, and 11 (28%) were negative for 165 rDNA multiplex PCR reaction. Nine samples (28.6%) exhibited a mixed infection and were positive for both H. infuenzae and M. catarrhalis. We suggested that 16S rDNA multiplex PCR is a useful method to identify rapidly for rapid identification of the pathogenic bacteria and characterization of bacterial etiologies of middle ear effusion.

• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.33-39
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• 2001

An isolate of the indigenous fungus Pythium myriotylum was isolated from Monochoria vaginalis in Yusung, Korea in year 2000 and evaluated potential as a biocontrol agent in laboratory and greenhouse. P. myriotylum MD2 grew in a wide range of temperature regimes and the optimal growth temperature was $35^{\circ}C$. The fungus was highly pathogenic to Monochoria vaginalis at 30 to $35^{\circ}C$. Several weeds such as Rotala, indica, Lindernia procumbens, Ludwigia prostrata, Cyperus difformis, Scirpus juncoides, Aneilema keisak were also susceptible to the fungus, but Echinochloa crus-galli was not. The fungus affected the growth of rice seed germinated, but not to rice seedlings of 1- to 3-leaf stage. A total of 12 rice cultivars (3- to 4-leaf stage) tested showed no disease symptoms when inoculated with the fungus. Eleven crops, including Chinese cabbage, corn, soybean except wheat were immune to the infection of the fungi. These data suggest that P. myriotylum MD2 has a potential as a mycoherbicide to control weeds in paddy fields.

• Korean Journal of Clinical Laboratory Science
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• v.50 no.3
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• pp.275-283
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• 2018

Helicobacter pylori is a causative organism of various gastrointestinal diseases, including chronic gastritis, gastric ulcer, or gastric adenocarcinoma. Pathogenic factors, such as cytotoxin-associated protein A (CagA) and vacuolating cytotoxic protein A (VacA), play a role. This study analyzed qualitatively and quantitatively the effects of zerumbone on the changes in the protein expression levels of various H. pylori proteins, including CagA and VacA. Approximately 200 significant proteins were screened for the H. pylori 60190 (VacA positive / CagA positive; Eastern type) strain, and proteomic analysis was performed on 13 protein molecules that were clinically significant. After two-dimensional electrophoresis (2-DE), $ImageMaster^{TM}$ 2-DE Platinum software was used for quantitative measurements of protein spots. Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-TOF-MS) and liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) were used for protein identification. After intensive analysis of the proteins that showed significant changes, a reverse transcription-polymerase chain reaction was performed as required to verify the results. In this study, the significance of zerumbone as a therapeutic agent for H. pylori infection was examined by screening a new pharmacological activity mechanism of zerumbone.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.237-243
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• 2020

Listeria sp. is one of the pathogenic bacteria causes the infection listeriosis, through mainly raw food such as fishery food, dairy food and vegetables. Listeria sp. is a Gram-positive, non-spore-forming, motile, and facultative anaerobic bacterium. Because of the tolerance of Listeria sp. to low temperature and high salt concentration, it is very difficult to prevent them contaminated in the food, which do not require heating, especially, such as raw fishery products. So prevention and removal of bacterial contamination at the food manufacturing stage is the best method. In this study, therefore, several natural products including Psidium guajava and Geranium thunbergii were screened to investigate the antibacterial activity against Listeria sp., with expectation of fewer side effects and fewer resistance problems. Significant effects of two extracts were confirmed by well diffusion assay, MIC assay, and growth inhibition assay. P. guajava and G. thunbergii showed MIC values at 64-256 ㎍/mL meaning strong antibacterial activities against 6 kind of Listeria sp. tested. And the growth of Listeria sp. in the liquid media was actually inhibited by the addition of these two extracts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.346-354
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• 2018

In the probe of a medical ultrasound device, three parts were selected randomly by the examiner and the bacteria in the probe were detected by the blood examiners. In addition, the degree of death of the pathogenic bacteria after each disinfection of the detected pathogens, disinfecting ethanol, and disinfecting tissue of the detected pathogens were analyzed quantitatively. The following was detected: S Aureus (32.3 %), Bacillus spp. (26.5 %), Micrococcus spp. (21.5 %), and CNS (20 %). With the conventional probe, S. aureus (26.2 %), a playback curve (24.2 %), and a micron (19.5 %), Micrococcus spp. (15.5 %), and CNS (14.6 %) were observed. In the fan probe, S. aureus (24.7 %), Enterococcus (24.7 %), Enterococcus (17.7 %), and CNS (13.8 %) were detected. The disinfection of the three pathogens detected revealed sterilization of most of the pathogens, and most cases contained at least 91.3 % of the total sterilizing effect (P>0.05). In addition, for the disinfection of Propolis extract and disinfecting tissue, the disinfection effect was lower than that of disinfecting ethanol, but the difference was not statistically significant (P>0.05). The results revealed bacteria on most of the ultrasound probes. Antiseptic disinfection of surgical instruments using an extract of propolis works with results similar to those of ethanol. A blood test along with disinfection can help prevent infection if an ultrasound probe is applied to food.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.1 s.60
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• pp.47-52
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• 2007

The antimicrobial properties of medium-chain ($C_{8-12}$) free fatty acids and their 1-monoglyceride derivatives against a wide range of microorganisms we well known. However, previous studies have been mainly focused on the antimicrobial activity against pathogenic bacteria and viruses causing diseases in human or domestic animals' infection. But, there have been few reports describing comprehensive surveys of antimicrobial effects against microorganisms in cosmetics. For a start of this study, we evaluated and compared the preservative activities of $C_8$ (glyceryl caprylate) and $C_{12}$(glyceryl laurate) 1-monoglyceride in cosmetic formulations. From the result, we found that both of them have very excellent preservative activity against bacteria, but less against fungi. And $C_8$ 1-monoglyceride was a little bit more effective than $C_{12}$ 1-monoglyceride. According to the test results to evaluate each antimicrobial activity of glyceryl caprylate towards 5 kinds of microorganisms used in preservation efficacy test in cosmetics, gram-positive bacteria S. aureus and yeast C. albicans were sensitive and mold A. niger was most tolerant to glyceryl caprylate. Therefore, we tried to improve the antimicrobial activity of glyceryl caprylate agianst mold such as A. niger so that we could make it used as a preservative for cosmetic products. As a result, we confirmed that the antimicrobial activity of glyceryl caprylate is much improved under acidic conditions in formulation. In addition, we found optimal combinations of glyceryl caprylate with other antimicrobial agents. Among tested 7 antimicrobial agent, methyparaben showed the highest preservative activity in combination with gglyceryl caprylate.

• Korean journal of applied entomology
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• v.42 no.4
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• pp.353-360
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• 2003

Immunodepression can be required for entomopathogenic bacteria to induce their potent pathogenicities to the target insects. Here, we raise a hypothesis that the capacity of a pathogenic bacterium to induce the target insect immunodepression has positive relationship with the degree of pathogenicity. X. nematophilus had 1,200 times as potent as another entomopathogenic bacterium, Staphylococcus gallinarum against the fifth instar larvae of silkworm, Bombyx mori, when they were Injected into the hemocoel. Although both bacteria had significant cytotokic effect on the hemocytes of B. mori, X. nematophilus gave faster and greater cytotoxicity than did S. gallinarum. In cellular immune reactions, B. mori could form 20 hemocyte nodules against the bacterial injection with 5${\times}$10$\^$5/ cells. The number of the hemocyte nodules was significantly depressed when live X. nematophilus was inject-ed, but not in S. gallinarum. Activation of prophenoloxidase (proPO) was depressed in the bacterial injection. The depression of PO activation was significantly greater in X. nematophilus infection than in S. gallinarum injection. Lysozyme activity was induced by the injection of S. gallinarum at 4 h after the treatment, but not induced in X. nematophilus at all the time. These results showed that X. nemato-philus induced greater immunodepression against B. mori and resulted in higher pathogenicity than did S. gallinarum. Therefore, this study suggests that the immunodepression induced by entomopathogenic bacteria has positive relationship with their pathogenicity.

• Journal of Life Science
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• v.28 no.1
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• pp.78-82
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• 2018

Detection of pathogenic microorganisms takes several days by conventional methods. It is necessary to assess microorganisms in a timely manner to reduce the risk of spreading infection. For this purpose, bacteriophages are chosen for use as a biosensing tool due to their host specificity, wide abundance, and safety. However, their lytic cycle limits their efficacy as biosensors. Phage proteins involved in binding to bacteria could be a robust alternative in resolving this drawback. Here, a fragment of tail protein J (residues 784 to 1,132) of phage lambda fused with 6X His-tag (6HN-J) at its N-terminus was cloned, overexpressed, purified, and characterized for its binding with microorganisms. The purified protein demonstrated a size of about 38 kDa in sodium dodecyl sulfate - polyacrylamide gel electrophoresis (SDS-PAGE) and bound with anti-His monoclonal antibodies. It bound specifically to Escherichia coli K-12, and not Salmonella typhimurium, Bacillus subtilis, or Pseudomonas aeruginosa in dot blotting. Binding of the protein to E. coli K-12 inhibited about 50% of the in vivo adsorption of the phage lambda to host cells at a concentration of $1{\mu}g/ml$ 6HN-J protein and almost 100% at $25{\mu}g/ml$ 6HN-J. The results suggest that a fusion viral protein could be utilized as a biosensing element (e.g., protein chips) for detecting microorganisms in real time.

• Research in Plant Disease
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• v.9 no.4
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• pp.217-220
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• 2003

A severe fruit rot of Persimmon (Diospyros kaki cv: Fuyu) was occurred during the storage and transport that infected with blue mold in Sweet Persimmon Experiment Station, Gyeongsangnam-do Agricultural Research and Extension Services, Korea. Fruit surfaces were infected with the fungus first and the colonized fungus formed mycelial mats. From the point of infection, fruits become collapsed and mostly ruptured. The pathogenic fungus from infected fruits was isolated and cultured on PDA. Colony color of the fungus was white at frist than became green on Malt Extract Agar and Czapek Yeast Extract Agar. Conidia were ellipsoid subglobose and 2.6${\sim}$3.8 ${\times}$ 2.4${\sim}$3.8 ${\mu}m$ in size. Stipes were 86${\sim}$320 ${\times}$ 2.8${\sim}$4.3 ${\mu}m$ in size. Rami were 7.5${\sim}$32.6 ${\times}$ 2.6${\sim}$4.2 ${\mu}m$ in size, Ramuli were 12.4${\sim}$14.8 ${\times}$ 3.2${\sim}$3.8 ${\mu}m$ in size, Metulae were 8.9${\sim}$13.6 ${\times}$ 2.8${\sim}$4.6 ${\mu}m$ in size. Phialides were ampulliform, 8.2${\sim}$12.4 ${\times}$ 2.3${\sim}$3.6 ${\mu}m$ in size. Based on the cultural and mycological characteristics and pathogenecity test on host plants, the fungus was identified as s, This is the first report on the blue mold of Persimmon (Diospyros kaki) caused by P. crustosum in Korea.