• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.194-199
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• 2010

Compost as a soil amendment is of importance in enhancing the soil chemical and microbial qualities; however, soil microbial community can vary depending on the composition, and the amount of compost applied to plant in the soil. Responses of soil microbial properties to compost applications with 0, 30, and 60 Mg $ha^{-1}$ were investigated in silt loam soils where red pepper(Capsicum annuum L.) was mainly cultivated in Yeongyang, Gyeongbuk, Korea. The analysis of phospholipid fatty acids (PLFAs) extracted from soil showed that compost amounts significantly increased PLFAs representing as bacteria, fungi, and VAM-fungi as well as the ratio of fungi/bacteria, and monounsaturated/saturated PLFAs. Increasing the amount of compost significantly increased Gram-/Gram+ PLFAs' ratio, but significantly decreased monounsaturated/saturated PLFAs' ratio. Therefore, this result shows that compost would vary to a limited extent the microbial community in red pepper field. However, increase in compost application would change the subgroup structure of microbial community only.

• Microbiology and Biotechnology Letters
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• v.51 no.2
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• pp.203-207
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• 2023

The N₂O-reducing rhizobacterium, Pseudomonas sp. M23, was isolated from maize rhizosphere soil. The maximum N₂O reduction rate of the strain M23 was 15.6 mmol·g-dry cell weight^-1·h^-1. Its N₂O reduction activity was not inhibited by diesel contaminant, and it was enhanced by the addition of the root exudates of maize and tall fescue. The remediation efficiency of diesel-contaminated soil planted with maize or tall fescue was not inhibited by inoculating with the strain M23. Root weights in the soil inoculated with the strain M23 were greater than those in the non-inoculated soil. These results suggest that Pseudomonas sp. M23 is a promising bacterium to mitigate N₂O emissions during the remediation of diesel-contaminated soil.

• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.152-156
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• 2012

Methanotrophic communities from freshwater wetland (FW), seawater wetland (SW), forest (FS), and landfill soils (LS) around Seoul of South Korea, were characterized using comparative sequence analyses of clone libraries. Proportions of Methylocaldum, Methlyococcus and Methylosinus were found to be greater in FW and SW, while Methylobacter and Methylomonas were more notable in FS and Methylocystis and Methylomicrobium more prominent in LS. Lag periods behind the initiation of methane oxidation significantly varied amongst the soils. Methane oxidation rates were greater in $FW{\geq}LS{\geq}SW>FS$ (p<0.05). Thus, the environmental setting is a significant factor influencing the communities and capabilities of methanotrophs.

• The Korean Journal of Pesticide Science
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• v.21 no.1
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• pp.1-8
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• 2017

Although a global ban on the use of endosulfan, an organochloline insecticide, has taken effect in mid-2012, it has been still used in several countries, including India and China, and detected in diverse environments in the world due to its relative persistence and semi-volatility. In this study, the effect of endosulfan on soil bacterial community was investigated using 16S rRNA gene pyrosequencing method. When endosulfan was applied to an upland soil at a rate of 100 mg/kg soil (ES soil), the number of operational taxonomic units (OTU) and diversity indices for bacteria initially decreased and gradually recovered to the level of the non-treated soil (NT soil) during an eight-week incubation period. At bacterial phylum level, relative abundances of Proteobacteria and Verrucomicrobia were higher while those of Chloroflexi and Spirochaetes were lower in the ES soil than in the NT soil, suggesting that an endosulfan application affects the bacterial community structure in soil. In the ES soil, the relative abundances of the OTUs affiliated to the genera Sphingomonas and Burkholderia increased in the initial period of incubation while those affiliated to the genera Pseudonocardia and Opitutus increased in the late period of incubation. Because the first three genera contain bacterial strains reported to degrade endosulfan, they are expected to be involved in the degradation of endosulfan, probably one after another.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.479-484
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• 2011

Fatty acid methyl ester (FAME) profiles were used to describe differences in soil microbial communities influenced by conventional farming system (CFS), conventional farming system without pesticides (CFSWP), and organic farming system (OFS) for strawberry cultivation in controlled horticultural land. In comparison to the CFS soils, the average soil microbial biomasses of in the OFS soils were approximately 1.2 times for total FAMEs ($195nmol\;g^{-1}$), 1.4 times for total bacteria ($58nmol\;g^{-1}$), 1.5 times for Gram-negative bacteria ($27.3nmol\;g^{-1}$), 1.2 times for Gram-positive bacteria ($26.1nmol\;g^{-1}$), and 1.5 times for actinomycetes ($2.8nmol\;g^{-1}$). The microbial communities of total bacteria (p<0.05) and Gram-negative bacteria (p<0.05) in the OFS and CFSWP soils were significantly higher larger than those in the CFS soils. However, fungal structure was significantly greater in CFS than in OFS and CFSWP (p<0.05). In principal component analyses of soil microbial communities, our findings suggest that actinomycetes should be considered as potential factor responsible for the clear microbial community differentiation observed between OFS and CFS in controlled horticultural land.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.995-1001
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• 2010

Biogeography is the study of the distribution of biodiversity over space and time. We report the development of a prototype database that maps of microbial diversity in the context of the geochemical and geological environment and geographic location. It aims to reveal where organisms live, and at what abundance in nation wide. Microbial data collected from agricultural land during 1999 to 2007 were categorized for mapping with ArcGIS program. Distribution maps of bacteria, fungi, Bacillus and gram negative bacteria of agricultural land showed different patterns from each other. Microbial biomass content investigated in year of 2007 was higher than in 1999.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.534-541
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• 2019

his study assessed microbial contamination of leeks and leek-cultivated soil. Leeks and leek-cultivated soil were collected in A and B regions and accounted for 39 and 33 samples, respectively. All of the samples were analyzed for the presence of sanitary indicator bacteria (total aerobic bacteria, coliforms and Escherichia coli), Salmonella spp., E. coli O157:H7, Listeria monocytogenes, and Bacillus cereus. In A and B region, the total aerobic bacteria was in the range of 5.87-8.78 log CFU/g for leeks and 5.94-8.45 log CFU/g for leek-cultivated soil. The coliform in leeks and leek-cultivated soil was in the range of 1.20-7.36 log CFU/g and 2.45-5.87 log CFU/g, respectively. B. cereus was detected from some of the samples while other pathogens were not detected. This study provides important background information on the microbiological safety of fresh vegetable cultivation environments.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.278-285
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• 2010

We examined the distribution of exopolysaccharide (EPS) producing bacteria population in rhizosphere soils of domestic medicinal herbs; Angelica sinensis, Atractytodes japonica, Achyranthes japonica, Anemarrhena asphodeloides, and Astragalus membranaceus. Fifty-six percent of the total isolates from rhizosphere soil of Angelica sinensis were EPS producing bacteria, suggesting the dominance of EPS producing bacteria in rhizosphere soil of Angelica sinensis. EPS producing bacteria were enumerated in root system (rhizosphere soil, rhizoplane, inside of root) of Angelica sinensis. Bacterial density of rhizosphere soil, rhizoplane, and inside of root were distributed $9.0{\times}10^6CFU/g{\cdot}soil$, $7.0{\times}10^6CFU/g{\cdot}soil$, and $1.4{\times}10^3CFU/g{\cdot}soil$, respectively. EPS producing bacteria from rhizosphere soil were categorized into five major phylogenetic groups: Alphaproteobacteria (4 strains), Betaproteobacteria (6 strains), Firmicutes (2 strains), Actinobacteria (3 strains), and Bacteroidetes (1 strain) subdivisions. Also, the EPS producing isolates from rhizoplane were distributed as 7 strains in Alphaproteobacteria, 3 strains in Betaproteobacteria, 2 strains in Actinobacteria, 3 strains in Bacteroidetes, and 1 strain in Acidobacteria subdivisions. All of the EPS producing bacteria inside of root belong to genus Chitinophaga. Burkholderia caribiensis DR14, Terriglobus sp. DRP35, and Rhizobium hainanense SAP110 were selected in 112 EPS producing bacteria. These appeared to have produced high levels of exopolysaccharide 6,555 mpa.s, 3,275 mpa.s, and 1,873 mpa.s, respectively. The purified EPS was analyzed Bio-LC. As neutral sugars, glucose, galactose, mannose were detected and as amino sugars, galactosamine and glucosamine were detected. Especilally, analysis of Bio-LC showed that Rhizobium hainanense SAP110 produced glucose (60~89%) and glucosamine (8.5%) as major neutral sugar and amino sugar, respectively.

• Research in Plant Disease
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• v.12 no.3
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• pp.267-271
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• 2006

Botrytis cinerea Pers. was found to be highly virulent to the grapevine plant, especially in greenhouse condition. Pseudomonas species play key roles for the biocontrol of many plant diseases especially in soil. Of the 83 isolates of Pseudomonas spp., a bacterial strain P84, isolated from tomato rhizosphere, was shown to suppress a wide range of phytopathogenic fungi in vitro. The isolate was identified as Pseudomonas putida on the basis of its bacteriological and genetic characteristics. The P. putida P84 strain carry the phlD gene for 2,4-diacetylphloroglucinol biosynthesis and may produce the antibiotics as an antagonistic mechanism involved in biocontrol. The antagonistic activity of the bacterium has a promising implication for its use as a biocontrol agent to control grapevine gray mold.

• Korean Journal of Microbiology
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• v.37 no.1
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• pp.85-91
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• 2001

Biological treatment of benzene and toluene contaminated soil was investigated in laboratory microcosm of 16 different types for degrading benzene and toluene by indigenous bacteria. At the experimental conditions of the microcosms fast degrading benzene and toluene, moisture contents were 30% and 60% in a soil gap and content of powdered-activated carbon(PCA) for adhesion of benzene and toluene-degrading bacteria was 1% in total soil mass. At the conclusion of the shifted bacteria community, Case 6 and case 7 were operated until 10 days, and then the total cell number and the number of benzene and toluene degrading bacteria were investigated. The total cell number of Case 6 and Case 7 increased 488 fold and 308 fold of total indigenous cell, respectively. The number of benzene and toluene degrading bacteria increased and maintained the percentages occupied in pre-operating microcosm. Species of benzene and toluene degrading bacteria in microcosm changed from species of Gram negative bacteria to Gram positive bacterial species after soil exposed to benzene and toluene.