• Korean Journal of Microbiology
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• v.51 no.4
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• pp.440-443
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• 2015

The widespread emergence of antibiotic resistant microorganisms in clinics and natural environments has attracted public concern. Especially, microorganisms inhabiting natural environment is considered as a source responsible for increasing the abundance of antibiotic resistant genes in ecosystem. In this study, the diversity of culturable bacteria resistant to ampicillin was investigated with water samples collected from seven locations in Korea. The genera belonging to Aeromonas and Acidovorax were dominant among the isolated 498 strains. The 66% of isolates showed multi-drug resistance against more than six antibiotics among tested fourteen ones and isolates resistant to seven antibiotics were the most prevalent with 19.7% abundance. Using the antibiotics susceptibility results, the intrinsic resistance profile was suggested for the most dominant genera, Aeromonas, Acidovorax, Pseudomonas, and Elizabethkingia.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.86-90
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• 2009

The definition of edible ice is frozen water for the use of food manufacturing, processing, or cooking, as well as for the direct eating. It has been reported that in the process of ice manufacturing and its selling, edible ice is contaminated with some microorganisms, which causes food poisoning and gastroenteritis. It was shown that besides in the edible ice, germ growth caused by various reasons occurred in the mineral water, tap water, water filtering system, and water purifier. With public awareness, in order to examine the sanitary conditions of edible ice in the Northern area of Daegu metropolitan city, 15 places were randomly selected. As a result, 14 places were found to be contaminated with microorganisms. After incubating on the Brain Heart Infusion (BHI) agar plate, 80% of Gram-negative bacilli, 17% of Gram-positive cocci, and 3% of Gram-negative cocci were cultured. Enterobacter cloacae, Chryseomonas luteola, Pantoea spp., Klebsiella pneumoniae, Acinetobacter baumannii, Acinetobacter calcoaceticus or Providencia rettgeri were detected. Gram-positive cocci cultured in BHI agar plate from 5 specimens were identified as Staphylococcus aureus or Staphylococcus xylosus, which is well known bacteria causing strong food poisoning. This present paper raises questions on the importance and awareness of sanitary conditions of edible ice and the identification of pathogenic microorganisms living in the edible ice in relation to their distribution. The examination of sanitary conditions of edible ice in other areas in Daegu seems to be also needed to find out if there are similar cases.

• The korean journal of orthodontics
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• v.36 no.4
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• pp.263-274
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• 2006

Objective: The purpose of this study was to evaluate clinical and microbiological changes in periodontal tissue around the banded molars after debanding. Methods: This study included 17 young adult patients treated with fixed orthodontic appliances including bands on the last molars more than 1 years. Probing depth and bleeding frequency were measured and plaque samples were collected from the last banded molars in all quadrants of each patient. All the data were collected immediately after debanding and 4 weeks after debanding. Results: Using polymerase chain reaction based on 16S rDNA, the presence of Porphyromonas gingivalis, Tannerella forsythia and Treponema denticola was detected. After debanding, probing depth, bleeding frequency, and prevalance of periodontopathogens were reduced. Probing depth and bleeding frequency were most decreased in the buccal site of the mandibular left molar and were least decreased in the lingual site of the maxillary right molar. Conclusion: The results of this study indicated that proper management of oral hygiene after debanding can recuperate unfavorable periodontal condition caused by orthodontic treatment.

• Journal of Life Science
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• v.29 no.2
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• pp.248-255
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• 2019

This research confirmed the diversity and characterization of gut microorganisms isolated from the intestinal organs of Muraenesox cinereus, collected on the Samcheonpo Coast and Seocheon Coast in South Korea. To isolate strains, Marine agar medium was basically used and cultivated at $37^{\circ}C$ and pH7 for several days aerobically. After single colony isolation, totally 49 pure single-colonies were isolated and phylogenetic analysis was carried out based on the result of 16S rRNA gene DNA sequencing, indicating that isolated strains were divided into 3 phyla, 13 families, 15 genera, 34 species and 49 strains. Proteobacteria phylum, the main phyletic group, comprised 83.7% with 8 families, 8 genera and 26 species of Aeromonadaceae, Pseudoalteromonadaceae, Shewanellaceae, Enterobacteriaceae, Morganellaceae, Moraxellaceae, Pseudomonadaceae, and Vibrionaceae. To confirm whether isolated strain can produce industrially useful enzyme or not, amylase, lipase, and protease enzyme assays were performed individually, showing that 39 strains possessed at least one enzyme activity. Especially the Aeromonas sp. strains showed all enzyme activity tested. This result indicated that isolated strains have shown the possibility of the industrial application. Therefore, this study has contributed for securing domestic genetic resources and the expansion of scientific knowledge of the gut microbial community in Muraenesox cinereus of South Korea.

• Journal of the Speleological Society of Korea
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• v.27 no.28
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• pp.85-91
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• 1991

동굴생물은 식물과 동물, 미생물로 크게 구분되지만 태양광선이 완전히 차단된 동굴내 환경에서는 동굴동물들이 주종을 이루고 있다. 동굴내의 동물에 관한 연구는 1966년 고씨동굴, 용담굴을 시발로 고수굴, 천동굴, 노동굴, 백용굴, 대이굴 한선굴등 강원도내에 분포하는 동굴중 약 30%정도는 동물을 포함한 생물상이 조사되었다. 강원도의 동굴동물로서 확인된 것은 9강 309 141종이며 강별로는 충강이 9목 50종 주형강이 4목 49종 갑각강이 6목 18종의 순으로 우세하고 목별로는 거미 목이 15과 39종, 톡토기목이 7과 20종, 딱정벌레 목이 8과 15종으로 우세한 편이다(남, 1987)(중략)

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.303-311
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• 1996

The microflora changes of 10 water-controled treatments combined with livestock manures(pig, chicken) and bulking agents(sawdust, paper sludge) were investigated. The B/F values of the P-1 and C-1(65%, $H_2O$) treatments were 3571 and 5400 respectively, but those of the P-4 and C-4(50%, $H_2O$) treatments showed very low values, 667 and 334, respectively. The B/F values tended to increase with higher water content of the treatments. In the composting processes, the successions of microflora, adapting the compost environments, took place via fluctuating temperature. In the high temperature period, the numbers of mesophilic bacteria and fungi decreased, but that of the spore forming bacteria increased. However, the number of mesophilic bacteria inereased during the cold period. The B/F values of compost ranged 25-300, which indicates a decrease in the quantity of bacteria. The time required for the temperature of compost to reach $60^{\circ}C$ showed different patterns. There was no pathogenic microorganism in the treatments which reached a high temperature in a short period of time, but, in the treatments which reached a high temperature over a Long period of time, the pathgenic microorganism was not still alive.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.7
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• pp.503-508
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• 2013

The aim of this study was to investigate the microbial communities in animal carcass disposal soils to examine the possible threat of pathogens from leachate. DNA extraction was performed for the soils in three carcass disposal sites located in Gyeonggi-do, Korea, and then 16S rRNA pyrosequencing was conducted to identify the microbial communities. Results indicate that, according to phylum classification, Proteobacteria (100%) was identified in soil A, Actinobacteria (66.4%) > Proteobacteria (31.1%) > Bacteriodetes (2.1%) > Acidobacteria (0.3%) in soil B, and Actinobacteria (63.1%) > Proteobacteria (36.9%) in soil C. According to genus classification, Pseudomonas was dominant in soil A (98%), Arthrobacter in soil B (68%) and C (61%). There were no detections of pathogens such as Salmonella, Campylobacter and Clostridium perfringens. However, high concentration of Ralstonia pickettii causing bacteremia was observed. Although carcass disposal soils examined in this study were not highly contaminated with pathogens, further monitoring is still needed to examine the potential threat of pathogens in leachate derived from carcass disposal sites.

• Journal of Wetlands Research
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• v.16 no.3
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• pp.315-325
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• 2014

Valuation of ecosystem services through organic carbon distribution and cycling in the Quercus mongolica forest at Mt. Worak national park were investigated from May 2012 through April 2013. The amount of carbon allocated to above and below ground biomass was 81.94 and 20.53 ton C/ha. Amount of organic carbon in litter layer was 6.49 ton C/ha. Amount of organic carbon within 50 soil depth was 141.23 ton C $ha^{-1}$ $50cm-depth^{-1}$. Total amount of organic carbon in this Quercus mongolica forest was estimated to 250.19 ton C $ha^{-1}$. The estimated amount of won in this Quercus mongolica forest in terms of total organic carbon was about 5.27 million won $ha^{-1}$. The amount of carbon evolved through soil respiration was 7.31 ton C $ha^{-1}yr^{-1}$. The amount of carbon evolved through microbial respiration and root respiration was 3.58 and 3.73 ton C $ha^{-1}yr^{-1}$, respectively. The amount of organic carbon absorbed from the atmosphere of this Quercus mongolica forest was 1.61 ton C $ha^{-1}yr^{-1}$ when estimated from the difference between net primary production and microbial respiration. This amount will come to about 33,000 won $ha^{-1}yr^{-1}$ in Korean currency.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.332-338
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• 2015

Valuation of ecosystem services through organic carbon distribution and cycling in the Pinus densiflora forest at Mt. Worak National Park were investigated from January 2013 through December 2013. The amount of carbon allocated to above and below ground biomass was 32.17 and 8.04 ton C $ha^{-1}$. Amount of organic carbon in litter layer was 5.55 ton C $ha^{-1}$. Amount of organic carbon within 50cm soil depth was 58.62 ton C $ha^{-1}$ 50cm-$depth^{-1}$. Total amount of organic carbon in this Pinus densiflora forest was estimated to 104.38 ton C $ha^{-1}$. The estimated amount of won in this Pinus densiflora forest in terms of total organic carbon was about 10.44 million won $ha^{-1}$. The amount of carbon evolved through soil respiration was 4.44 ton C $ha^{-1}yr^{-1}$. The amount of carbon evolved through microbial respiration and root respiration was 2.18 and 2.27 ton C $ha^{-1}yr^{-1}$, respectively. The amount of organic carbon absorbed from the atmosphere of this Pinus densiflora forest was 0.44 ton C $ha^{-1}yr^{-1}$ when estimated from the difference between net primary production and microbial respiration. This amount will come to about 44,000 won $ha^{-1}$ in Korean currency.

• Korean Journal of Organic Agriculture
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• v.28 no.2
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• pp.235-250
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• 2020

Agricultural practices are known to have a crucial influence not only on soil physico-chemical properties but also on microbial communities. To investigate the effect of farming practices on soil microbial communities, a total of 10 soil samples were collected, including five conventional and five organic farming soils cultivated with peppers in plastic greenhouse. We conducted barcorded-pyrosequencing of V1-V3 regions of 16S rRNA genes to examine soil microbial communities of two different farming practices. Taxonomic classification of the microbial communities at the phylum level indicated that a total of 22 bacterial phyla were present across all samples. Among them, seven abundant phyla (>3%) including Proteobacteria, Actinobacteria, Firmicutes, Acidobacteria, Bacteroidetes, Chloroflexi, and Gemmatimonadetes were found, and Proteobacteria (33.0 ± 5.7%), Actinobacteria (19.9 ± 9.7%), and Firmicutes (13.6 ± 5.0%) comprised more than 66% of the relative abundance of the microbial communities. Organic farming soils showed higher relative abundances of Proteobacteria and Firmicutes, while Actinobacteria and Chloroflexi were more abundant in conventional farming soils. Notably, the genera Bacillus (higher in organic farming soils) and Streptomyces (higher in conventional farming soils) exhibited significant variation in relative abundance between organic and conventional farming soils. Finally, correlation analysis identified significant relationships (p<0.05) between soil chemical properties, in particular, pH and organic matter content and microbial communities. Taken together, this study demonstrated that the changes of soil physico-chemical properties by agricultural farming practices effected significantly (p<0.05) on soil microbial communities.