• Food Science and Biotechnology
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• v.16 no.4
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• pp.615-620
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• 2007

Commercially packed kimchi products from 6 different manufacturers, which are exported overseas as well as sold domestically, were analyzed to determine their microorganism distributions and presence of pathogenic bacteria. All samples showed decreasing pH levels (from 5.7-6.2 to 3.9-4.3) and increasing titratable acidities (from 0.3-0.4 to 0.8-1.2%) during 15 days of storage at $4^{\circ}C$. Total bacterial counts ranged from $2.1{\times}10^5-1.9{\times}10^6\;CFU/mL$ in the initial kimchi samples, and then increased to $1.1{\times}10^8-1.8{\times}10^9\;CFU/mL$. The coliform numbers decreased from approximately $2.5{\times}10^2-1.7{\times}10^4\;CFU/mL$ to zero. Major foodborne pathogens such as Salmonella spp., Staphylococcus aureus, Escherichia coli O157:H7, Listeria monocytogenes, Bacillus cereus, Yersinia enterocolitica, and Shigella spp. were not detected in any of the samples. However, 2 out of the 6 samples carried E. coli, emphasizing the need for improved hygiene practice. Interestingly, Hafnia alvei, belonging to the Enterobacteriaceae family, was isolated in all of the samples. Further study is needed on this newly reported bacterium in kimchi.

• Mycobiology
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• v.49 no.3
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• pp.294-296
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• 2021

An endolichenic fungus, Xylaria grammica strain EL000614, showed strong nematicidal effects against plant pathogenic nematode, Meloidogyne incognita by producing grammicin. We report genome assembly of X. grammica EL000614 comprised of 25 scaffolds with a total length of 54.73 Mb, N50 of 4.60 Mb, and 99.8% of BUSCO completeness. GC contents of this genome were 44.02%. Gene families associated with biosynthesis of secondary metabolites or regulatory proteins were identified out of 13,730 gene models predicted.

• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.419-429
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• 2023

Ultraviolet C (UV-C, 200-280 nm) light has germicidal properties that inactivate a wide range of pathogenic and spoilage microorganisms. UV-C has been extensively studied as an alternative to thermal decontamination of fruit juices. Recent studies suggest that the efficacy of UV-C irradiation in reducing microorganisms in fruit juices is greatly dependent on the characteristics of the target microorganisms, juice matrices, and parameters of the UV-C treatment procedure, such as equipment and processing. Based on evidence from recent studies, this review describes how the characteristics of target microorganisms (e.g., type of microorganism/strain, acid adaptation, physiological states, single/composite inoculum, spore, etc.) and fruit juice matrices (e.g., UV absorbance, UV transmittance, turbidity, soluble solid content, pH, color, etc.) affect the efficacy of UV-C. We also discuss the influences on UV-C treatment efficacy of parameters, including UV-C light source, reactor conditions (e.g., continuous/batch, size, thickness, volume, diameter, outer case, configuration/arrangement), pumping/flow system conditions (e.g., sample flow rate and pattern, sample residence time, number of cycles), homogenization conditions (e.g., continuous flow/recirculation, stirring, mixing), and cleaning capability of the reactor. The collective facts indicate the immense potential of UV-C irradiation in the fruit juice industry. Existing drawbacks need to be addressed in future studies before the technique is applicable at the industrial scale.

• Food Science and Preservation
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• v.12 no.6
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• pp.637-642
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• 2005

The antibacterial effect of methanol and water extracts from edible mushrooms on the growth of pathogenic bacteria (Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Echerichia coli O-157, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhi) were investigated. The Lyophyllum cinerascens and Pleurotus ostreatus2 methanol extracts treated with 5.0 mg/disc showed the highest antimicrobial activity against 7 kinds of pathogenic bacteria. And methanol extracts of edible mushrooms showed higher antimicrobial activity against gram positive and gram negative microorganisms than water extracts. The methanol extracts of mushrooms revealed high inhibitive activites in cytotoxicity on human cancer HepG2 and HT-29 cells. The growth of cancer HepG2 and HT 29 cells which treated with 1 mg/mL of Cordyceps militaris and Sarcodon aspratus methanol extracts were strongly inhibited to $67\%$ and $81\%$ respectively. And most of the methanol extracts exhibited the stronger effects against these cells, at the same concentration, comparing with water extracts. Particularly, the methanol and water extracts of Cordyceps militaris, Agaricus blazei, Lyophyllum ulmarium, Ganoderma lucidum and Sarcodon aspratus have the strongest antitumoral effects on HepG2 and HT-29 cells. From these results, it is considered that wild mushrooms have stronger antimicrobial and in vitro cytotoxic effects.

• Korean Journal of Medicinal Crop Science
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• v.8 no.2
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• pp.109-116
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• 2000

This study was carried out to screen herbs among herbal plants showing antimicrobial activity against some food spoilage and pathogenic microorganisms. One hundred fifteen kinds of herbal plants were extracted by 70% ethanol, and then they have been screened for antimicroorganisms. Six herbal plants such as Salviae radix, Dryopteris rhizoma, Terminaliae fructus, Araliae radix, Psoraleae fructus and Schisandrae fructus showed strong antimicrobial activities against Bacillus subtilis. Antimicrobial activities were showed in Anemarrhena radix and Dryopteris rhizoma on Candida albicans, and in Anemarrhenae radix, Dryopteris rhizoma and Polygalae radix on Schizosaccharomyces sp. It was revealed that eight herbal plants such as Dryopteris rhizoma, Salviae radix, Sappan ligunum, Sinomeniae radix, Schisandrae fructus, Rhui fructus, Sophorae radix and Inulae radix also showed antimicrobial activities on Streptococcus mutans. In addition, Anemarrhena radix, Curcuma tuber, Inulae radix, Polygonum radix, Sanguisorbae radix, Scutellariae radix and Terminaliae fructus and showed antimicrobial activities on Trichophyton mentagrophytes. Four kinds of herbal plants such as Dropteris rhizoma, Salviae radix, Terminaliae fructus and Scutellariae radix which showed broad antimicrobial spectrums were mixed by 1 : 1 ratio with the other herbal paints showing relatively strong microbial activities such as Terminaliae fructus, Sinomeniae radix and Scutellariae radix etc. The extracts of mixed herbal paints showed higher antimicrobial activities than those of single herbal plant.

• Korean Journal of Veterinary Research
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• v.46 no.3
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• pp.255-261
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• 2006

Experimental animals have been used to biological and medical purposes and the animals must be, for these purposes, healthy and clean to microbial infection. However, the animals can be easily exposed to pathogenic microorganism via several routes. Of the routes, environmental conditions are the most important factors to keep the animals healthy and clean, especially air condition. Monitoring of air-condition has been required to keep the animal healthy and clean. However, any guideline is not available for experimental conditions with pigs. Therefore, the sampling times and points were compared in different conditions to establish an optimal protocol for monitoring of air borne bacteria. Tryptic soy agar(TSA), blood agar containing 5% defibrinated sheep blood and Sabraud dextrose agar(SDA) were used as media to capture total bacteria, pathogenic bacteria and fungi, respectively. Two methods, compulsive capture using an air-sampler and capturing fall-down bacteria were used to capture the microorganisms in the air. The points and time of capturing were different at each experiment. Air borne microorganisms were captured at three and five points in the open and closed equipments, respectively. Air was collected using an air-sampler for 1 min and 5 min and the agar plates as open status were left from 30 min to 2hr. At first, we monitored an experimental laboratory which dealt with several pathogenic bacteria and then, a protocol obtained from the investigation was applied to open or close experimental conditions with pigs. Number of bacteria was high from 10:00 to 15:00, especially on 13:30-15:30 but sharply decreased after 17:00. The tendency of the number of bacteria was similar between two methods even though the absolute number was higher with air sampler. Critical difference in the number of cells was observed at 5 min with air sampler and 2 hr with fall-down capturing method. However, 1 min with air sampler and 1 hr with fall-down capturing were the best condition to identify bacterial species collected from the air. Number of bacteria were different depending on the sampling points in closed condition but not in opened condition. Based on our results, a guide-line was suggested for screening air-borne microorganism in the experimental conditions with pigs.

• Mycobiology
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• v.40 no.1
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• pp.59-65
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• 2012

Antagonistic microorganisms against $Rhizoctonia$ $solani$ were isolated and their antifungal activities were investigated. Two hundred sixteen bacterial isolates were isolated from various soil samples and 19 isolates were found to antagonize the selected plant pathogenic fungi with varying degrees. Among them, isolate C9 was selected as an antagonistic microorganism with potential for use in further studies. Treatment with the selected isolate C9 resulted in significantly reduced incidence of stem-segment colonization by $R.$ $solani$ AG2-2(IV) in Zoysia grass and enhanced growth of grass. Through its biochemical, physiological, and 16S rDNA characteristics, the selected bacterium was identified as $Bacillus$ $subtilis$ subsp. $subtilis$. Mannitol (1%) and soytone (1%) were found to be the best carbon and nitrogen sources, respectively, for use in antibiotic production. An antibiotic compound, designated as DG4, was separated and purified from ethyl acetate extract of the culture broth of isolate C9. On the basis of spectral data, including proton nuclear magneric resonance ($^1H$ NMR), carbon nuclear magneric resonance ($^{13}C$ NMR), and mass analyses, its chemical structure was established as a stereoisomer of acetylbutanediol. Application of the ethyl acetate extract of isolate C9 to several plant pathogens resulted in dose-dependent inhibition. Treatment with the purified compound (an isomer of acetylbuanediol) resulted in significantly inhibited growth of tested pathogens. The cell free culture supernatant of isolate C9 showed a chitinase effect on chitin medium. Results from the present study demonstrated the significant potential of the purified compound from isolate C9 for use as a biocontrol agent as well as a plant growth promoter with the ability to trigger induced systemic resistance of plants.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.4
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• pp.33-46
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• 2006

Purpose : This study was conducted to investigate effects of 7 herbs among medicinals resolving dampness with aroma on vaginal microorganisms. Methods : Staphylococcus aureus, Methicillin- resistant Staphylococcus aureus, Candida albicans and Gardnerella vaginalis were used for vaginal pathogenic microorganisms. Lactobacillus gasseri, Streptococcus spp. and Escherichia coli HB101 were used for vaginal flora. Medicinals resolving dampness with aroma, Pogostemonis Herba, Amomi Cardamomi Fructus, Amomi Semen, Atractylodis Rhizoma, Ammomi Tsao-ko Fructus, Alpiniae Katsumadaii Semen and Magnoliae Cortex were used in this study. In vitro antimicrobial activities were observed by optical density and colony test. Results : The optical density showed that Alpiniae Katsumadaii Semen and Magnoliae Cortex among medicinals resolving dampness with aroma had antimicrobial effects on pathogenic vaginal microorganisms (Methicillin-resistant Staphylococcus aureus). Pogostemonis Herba, Ammomi Tsao-ko Fructus had antimicrobial effects on Gardnerella vaginalis. The colony test showed that Alpiniae Katsumadaii Semen, Magnoliae Cortex among medicinals resolving dampness with aroma had antimicrobial effects on Methicillin-resistant Staphylococcus aureus. Pogostemonis Herbs, Alpiniae Katsumadaii Semen had antimicrobial effects aganist Gardnerella vaginalis. The optical density showed that Magnoliae Cortex among medicinals resolving dampness with aroma had antimicrobial effect on normal vaginal microorganisms (Streptococcus spp.). The colony test showed that medicinals resolving dampness with aroma had no antimicrobial effect on normal vaginal microorganisms. Conclusion : From this study, we could suggest that Pogostemonis Herba, Ammomi Tsao-ko Fructus, Alpiniae Katsumadaii Semen, Magnoliae Cortex of medicinals resolving dampness with aroma are available to antimicrobial agent of pathogenic vaginal microorganisms in vitro.

• Korean Journal of Organic Agriculture
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• v.6 no.1
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• pp.133-149
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• 1997

Recently, the importance of management and cultivation of grasses has been increased in Korea. Among these cultural practices, the appropriate control of diseases is considered more important than other cultivation techniques such as fertilization and irrigation. The damages of brown patch and large patch caused by Rhizoctonia spp. and Pythium blight caused by Pythium spp. are serious in the major cultivation area of turfgrass in Korea. Since these diseases are difficult to control by agrochemicals, the damages are very serious if these are occured. The periodic spray of agrochemicals, to protect and control these diseases could make some problems of toxicity and environmental pollution as well as rising of non-target diseases. Therefore, the biological methods to control diseases have been required to decrease problems resulted from overuse of agrochemicals, to conserve natural ecosystem, and to control effectively diseases of grasses in the long period. The number of studies about biological control using antagonistic microorganisms have been increased for last half century. However, the application of biological control method has been very limited. In this study, thirteen isolates of R. cerealis, 8 isolates of R. solani and 3 isolates of Phthyn spp. have been isolated from diseased turfgrass in golf course and grass-culture area that have patch and wilting symptoms of zoysia grass and creeping bentgrass. Isolation frequency of R. cerealis and R. solani was high in especially zoysiagrass, while Pythym spp. was isolated from bent grass at low frequency but showed high pathogenicity. Totally, 205 isolates of soil microorganisms were isolated in this study as primary antagonistic microorganism by Herr's triple agar layer plate and dual culture method using rhizosphere of grasses, soil of crop field as the source of antagonistic microorganisms. Among the 205 isolates, 23 isolates were actinomycetes and 182 isolates were bacteria. All of the actinomycetes were isolated by Herr's method. Antagonistic effect of primary isolated microorganisms was tested for in vitro mycelial growth inhibition against pathogenic fungi isolated from grasses and for inhibition of disease occurrence in 24 well tissue culture plate and pot experiment. Then, four isolated of bacteria which are BG23, BG74, BG136 and BG171 were selected as antagonistic microorganisms against soil-born pathogenic fungi of bentgrass.

• 대한예방의학회:학술대회논문집
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• 2005.10a
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• pp.485-485
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• 2005