• Journal of Environmental Health Sciences
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• v.39 no.6
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• pp.513-521
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• 2013

Objectives: This study was performed in order to detect indicator bacteria in drinking spring water (DSW) samples in Seoul Metropolitan City, and to identify their genus through 16S rRNA sequencing and then assessing the genetic relation of their strains. Methods: For indicator bacteria detection and identification of total coliforms, we analyzed DSW between the spring and summer seasons. In particular, DSW samples were chosen from sites repeatedly found unsatisfactory in recent years. Results: Heterotrophic plate counts of DSW in the spring and summer season were investigated in the range of 0-550 and 0-800 CFU/mL, respectively. Total coliforms of these were 0-1,900 and 0-2,100 CFU/100mL, fecal coliforms were 0-600 and 0-550 CFU/100mL, and Escherichia coli were 0-7 and 0-326 MPN/100mL. The detection ratio of fecal pollution indicators and that of fecal coliforms increased to 58.6% in the summer from 12.5% in the spring and Escherichia coli increased to 51.4% from 4.7%. As a result of genetic analysis on the isolated bacteria, the genus of total coliforms was classified in the order of Enterobacter spp. 12.7%, Serratia spp. 7.3%, E. hermanii 6.4%, Rahnella spp. 5.5%, Hafnia spp. 4.5%, Escherichia coli 3.6%, Klebsiella spp. 3.6% in the spring season. In the summer season, it was classified in order of Klebsiella spp. 16.6%, Enterobacter spp. 13.0%, Escherichia coli 11.0%, Serratia spp. 8.6%, Raoultella spp. 7.0%, Kluyvera spp. 5.6% and Citrobacter spp. 3.0%. Conclusions: The increase of fecal pollution in summer indicates that special attention to drinking DSW is required.

• Korean Journal of Ecology and Environment
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• v.38 no.1 s.110
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• pp.18-29
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• 2005

This study was conducted to understand seasonal dynamics of phyto- and zooplankton communities in a shallow eutrophic reservoir (Shingu reservoir) from November 2002 to February 2004. Cyanophyceae dominated throughout the year, except for spring (March ${\sim}$ May) when Bacillariophyceae (Melosira varians) and Chlorophyceae (Dictyosphaerium puchellum) were dominant. The change of dominant species in Cyanophytes occurred in June and December 2003, and the increase of phytoplankton cell density in July and November was observed when the P loading through two inflows was high. In May, Oscillatoria spp. and Aphanizomenon sp. were dominant, but replaced by Microcystis spp. in the end of May. Dominant Microcystis spp. sustained until December and shifted to Oscillatoria spp. and Aphanizomenon sp. TN/TP ratio ranged from 13 to 46 (Avg. $27{\pm}6$) from June to December when cyanobacteria (Microcystis spp.) dominated. Rotifers such as Keratella cochlearis, Keratella valga, Polyarthra spp., Conochilus unicornis, Pompholyx complanata dominated in average 67.8% of the zooplankton community. Abundance of zooplankton was the highest in June 2003, when Pompholyx complanata (12,388 ind $L^{-1}$) was dominant. In May, the significant increase of Conochilus unicornis biomass ($1,048{\pm}28\;{\mu}g\;C\;L^{-1}$) was observed with distinct improvement of transparency ($Z_{eu}/\;Z_m=\;1.1$). These results suggest that the seasonal variation of phytoplankton communities in this reservoir are to be understood as results of multi-interactive factors such as temperature, light condition and nutrients, and small-sized rotifers as important predator.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.5
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• pp.19-26
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• 2013

This study was carried out to provide preliminary data for increasing biodiversity in agricultural ecosystem and investigate availability of using Tubificidae spp. for environment-friendly agriculture through the survey of growth of Tubificidae spp. in flooded paddy fields during winter. We estimated the number of Tubificidae spp. in rice paddy where had been flooded during the previous winter in Ganghwa-gun, Suwon-si, and Hwaseong-si (Bongdam-eup and Paltan-myeon) between March and April from 2010 to 2012. During growing period of rice, the number of Tubificidae spp. was compared between flooded and non-flooded paddy field in Ganghwa-gun. As results, mean density of Tubificidae spp. in winter flooded paddy field was 7,235.5 $ind./m^2$ in Ganghwa-gun, 14,347.5 $ind./m^2$ in Suwon-si, 59,989.9 $ind./m^2$ in Bongdam-eup, and 2,610.6 $ind./m^2$ in Paltan-myeon. Mean density of Tubificidae spp. was the highest in flooded paddy fields of Bongdam-eup that was kept wet until rice harvest time and had shallow water. While mean density was the lowest in Paltan-myeon where had deep water and later flooded paddy field than others. In Ganghwa-gun, during growing period of rice, mean density of Tubificidae spp. in flooded paddy fields (171,109.0 $ind./m^2$) and flooded fallow paddy fields (321,084.2 $ind./m^2$) was much higher than non-flooded paddy fields (1,006.6 $ind./m^2$). Flooded paddy field during winter can help increase the number of Tubificidae spp. which can control weeds and enhance biodiversity in paddy fields for environment-friendly agriculture. Early flooding and shallow water of paddy fields could be a good agriculture practice to encourage the growth of Tubificidae spp..

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.663-671
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• 2006

This study was performed for exploring the spatial distribution pattern of Pinus densiflora and Quercus spp. in Korea. Firstly, the spatial distribution map of Pinus densiflora and Quercus spp. was prepared in grid of $100m{\times}100m$ at national level, using digital forest type map and actual vegetation map. And thematic maps for topography, climate, and soil were also prepared in the raster form of $100m{\times}100m$. Through GIS based spatial analysis of the digital distribution map of Pinus densiflora and Quercus spp. and thematic maps, the spatial characteristics of Pinus densiflora and Quercus spp. distribution was explored in relation to the environmental factors such as topography, climate, and soil. And the occurrence frequency models of Pinus densiflora and Quercus spp. were derived. Pinus densiflora occurs more often than Quercus spp. at low elevation, low slope gradient, and high temperature areas. In addition, Pinus densiflora is mainly distributed at shallow and well-drained loamy soil from igneous rocks. In contrast, Quercus spp. is more common at shallow and well-drained loamy soil from metamorphic rocks. As a result, the prediction model for the spatial distribution of Pinus densiflora and Quercus spp. by topographical variables has proven successful with high statistical significance. The result of this study can contribute to rational management of Pinus densiflora and Quercus spp. stand in Korea, considering environmental factors such as topography, climate, and soil.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.4
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• pp.444-452
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• 2019

Carbapenem resistance, mediated by the major acquired metallo-β-lactamase (MBL) genes, has been increasingly reported, particularly for clinical isolates of Acinetobacter spp. Of the 191 nonduplicate clinical isolates of the carbapenem-nonsusceptible Acinetobacter spp. evaluated, 125 isolates (65.4%) were positive for the modified imipenem or meropenem-Hodge test, and 49 isolates (25.7%) were positive for the imipenem-EDTA+SMA double disk synergy test (DDS). PCR and sequencing of the bla_VIM-2-allele and bla_IMP-1-allele showed that 29 A. baumannii isolates and 1 A. calcoaceticus isolate had bla_VIM-2, whereas 16 A. baumannii isolates and 2 A. calcoaceticus isolates had bla_IMP-6; 1 isolate of the A. genomospecies 3 had bla_VIM-2 and bla_AIM-1. All the above MBL genes belong to class 1 integron. The size of class 1 integron encompassing bla_VIM-2 or bla_IMP-6 ranges from 2.8 kb to 3.2 kb in clinical isolates of A. baumannii, and 3.2 kb to 3.5 kb in clinical isolates of A. genomospecies 3. bla_VIM-2 was most often located first or second in the class 1 integron, and these integrons often included aacA4. Due to dispersion of the MBL-producing Acinetobacter spp. as well as integron, which may encompass various resistance genes, there is an expectation for the increase of multidrug resistant Gram-negative bacteria, including resistance of carbapenems such as imipenem or meropenem. Hence, the development of new antimicrobial agents for treating severe Acinetobacter spp. infections is needed.

• Food Science of Animal Resources
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• v.29 no.6
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• pp.702-708
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• 2009

We investigated biofilm formation in various media, growth in low pH, and the hemolytic activity of 14 strains of Cronobacter spp. (Enterobacter sakazakii) isolated from a variety of foods including powdered infant formula (n=75), infant cereal (n=100), honey (n=30), and other infant foods (n=100) in Korea. The Cronobacter spp. adhered and formed biofilms on polyethylene, and a greater extent of biofilm was observed in nutrient-rich media. No clear difference in biofilm-forming ability was noted among the media constituents and the pattern of biofilm formation was strain-dependent. Seven strains out of 14 strains (50%) grew at pH 4.1, indicating that the acid resistance of these Cronobacter spp. isolated in Korea was relatively low. Hemolytic activity was not observed in any of the strains. This study provides basic information for the physiological and biochemical characteristics of Cronobacter spp. isolated from a variety of infant foods in Korea.

• Journal of Food Hygiene and Safety
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• v.36 no.5
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• pp.407-417
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• 2021

In order to investigate frequency of fungal contamination in ginseng sprout, we collected 18 types of retail ginseng sprouts and analyzed them. Overall frequency of fungal contamination ranged from 113.3 to 174.1% with the highest occurrence of Penicillium spp. Fungal detection rate was significantly higher in moss than in stem, leaf and root of ginseng sprout. Penicillium spp. occurred in leaf and stem with the highest incidence and Fusarium spp., in root. Among Penicillium spp. and Fusarium spp., P. olsonii and F. oxysporum were dominant, respectively. Nine Fusarium species, Aspergillus westerdijkiae, Aspergillus flavus, and 11 Penicillium species were identified by phylogenetic analysis. PCR screening of mycotoxigenic potential revealed that 19 out of 25 isolates tested were positive for respective mycotoxin biosynthetic gene. Two 2 A. flavus and 11 A. westerdijkiae isolates produced varying amount of aflatoxin or ochratoxin A in czapek yeast extract brothsome of which showed high levels of mycotoxin production. These results suggests a need for continuous monitoring and management program to control fungal contamination in the ginseng sprout production chain.

• Korean journal of applied entomology
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• v.62 no.3
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• pp.117-124
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• 2023

The management of Ricania spp. is difficult because this pest has a wide host range and diverse habitats such as agricultural, suburban, urban, and forested areas. However, the researches for Ricania spp. management have been focused on only agricultural crops. Thus, it is required to determine the arboreal host preference of Ricania spp. at the surrounding areas of the farms to increase its management efficiency. To determine its host preference at arboreal plants, we reviewed the previous studies and investigated the densities of Ricania spp. at woody plants with high ecological importance but insufficiently studied. This study identified 120 species in 53 families of arboreal hosts of Ricania spp. Only Cornus officinalis and Styrax japonicus were preferred by all developmental stages of Ricania spp. The host preference of Ricania spp. was changed according to its developmental stages. This phenomenon would be caused by that each developmental stage of Ricania spp. would prefer different parts of woody plant, and require different nutrients for its survivor and reproduction. These results of this study could be helpful to make a plan of comprehensive management strategies for Ricania spp.

• Food Science of Animal Resources
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• v.34 no.5
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• pp.591-596
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• 2014

This study evaluated the effect of sodium diacetate and sodium lactate solutions for reducing the cell count of Pseudomonas spp. in frankfurters and hams. A mixture of Pseudomonas aeruginosa (NCCP10338, NCCP10250, and NCCP11229), and Pseudomonas fluorescens (KACC10323 and KACC10326) was inoculated on cooked frankfurters and ham. The inoculated samples were immersed into control (sterile distilled water), sodium diacetate (5 and 10%), sodium lactate (5 and 10%), 5% sodium diacetate + 5% sodium lactate, and 10% sodium diacetate + 10% sodium lactate for 0-10 min. Inoculated frankfurters and ham were also immersed into acidified (pH 3.0) solutions such as acidified sodium diacetate (5 and 10%), and acidified sodium lactate (5 and 10%) in addition to control (acidified distilled water) for 0-10 min. Total aerobic plate counts for Pseudomonas spp. were enumerated on Cetrimide agar. Significant reductions (ca. 2 Log CFU/g) in Pseudomonas spp. cells on frankfurters and ham were observed only for a combination treatment of 10% sodium lactate + 10% sodium diacetate. When the solutions were acidified to pH 3.0, the total reductions of Pseudomonas spp. were 1.5-4.0 Log CFU/g. The order of reduction amounts of Pseudomonas spp. cell counts was 10% sodium lactate > 5% sodium lactate ${\geq}$ 10% sodium diacetate > 5% sodium diacetate > control for frankfurters, and 10% sodium lactate > 5% sodium lactate > 10% sodium diacetate > 5% sodium diacetate > control for ham. The results suggest that using acidified food additive antimicrobials, as dipping solutions, should be useful in reducing Pseudomonas spp. on frankfurters and ham.

• Journal of Life Science
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• v.20 no.4
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• pp.578-583
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• 2010

It has been reported that extracts of globe thistle (Echinops spp.) and thistle (Circium spp., Carduus spp. and Onopordum spp.) have anti-bacterial and anti-fungal activities. Methanol extracts of Echinops setifer and Carduus spp. were used to test and see if the extracts of these plants could suppress growth of Mycobacterium smegmatis and Mycobacterium fortuitum. Although extract of Echinops setifer showed no anti-mycobacterial activities, extract of Carduus spp. showed inhibition zones when tested with filter discs. Genomic DNA was isolated from Carduus spp. and PCR was performed to clone a DNA fragment containing ITS1, 5.8S rRNA gene and ITS2. A 733-bp PCR product was obtained and its DNA sequence was reported to the GenBank (accession number GU188570). BLAST search of the obtained DNA sequence did not show a match with any DNA sequences in the Genbank. Carduus crispus and Carduus defloratus had the closest phylogenetic relationships to this plant.