• Korean Journal of Microbiology
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• v.39 no.1
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• pp.16-20
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• 2003

A phylogenetic analysis of bacterial populations inhabiting soil derived from serpentine was conducted. The samples were collected from adjacent metamorphic rocks and serpentinite soil at Kwangcheon. The pH of the serpentine areas ranged from 8.5 to 9.2. The number of bacteria on the DAL medium which was diluted with $10^{-2}$ of AL medium was 10~100 fold higher than that from the full strength of AL medium, and which indicates that oligotrophs are distributed in the serpentinite soil. Of a total of 76 isolates, 42 isolates were oligotrophic bacteria, which grew only on the DAL medium. Based on a phylogenetic analysis using 16S rDNA sequences, these isolates are found to fall within five major phylogenetic groups: proteobacteria $\alpha$-subdivision (3 strains), $\alpha$-subdivision (7 strains), $\gamma$-subdivision (2 trains); high G+C gram-positive bacteria (19 strains); low G+C grampositive bacteria (14 strains). Bacteria of the genus Streptomyces (high G+C division) and Bacillus (low G+C division) have been considered to form a numerically important fraction of serpentinite soil. Oligotrophic strains categorized as Afipia ($\alpha$-subdivision), Ralstonia, Variovorax ($\beta$-subdivision), Pseudomonas ($\gamma$ -subdivision), Arthrobacter (high G+C division), and Streptomyces (low G+C division).

• Korean Journal of Soil Science and Fertilizer
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• v.21 no.2
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• pp.135-140
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• 1988

A laboratory experiment was conducted to find out the number of soil microorganisms, identification and enumeration of soil microbial species on the mineral and volcanic ash soil with different cropping system of the Jeju Island. The results obtained were summarized as follows: 1. The number of bacteria was high in mineral soil with rotation of upland crops than that of volcanic ash soil with continuous cropping system. 2. According to identification of soil bacteria, the most of bacteria were composed to short rod with Gram negative. Among the bacteria species, Rhizobium spp. and Flavobacterium spp. were most high population in both of mineral and volcanic ash soil. 3. The number of fungi in mineral soils were reduced by the rotated cultivation of upland crops but no significant differences were observed in volcanic ash soil with continuous cropping system. On the other hand, Aspergillus spp., Fusarium spp., and Penicillium spp. were most high population in both of mineral and volcanic ash soil. 4. Comparing of the number and species ot microorganism to the cash crops soil in main land, about 10 to 100 times for bacteria and more than two times for the number and species of fungi were lowered in Jeju Island soil.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.819-823
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• 2011

The present study evaluated the seasonal changes of the soil microbial population by selected media in an organic farming system (OFS) with rye rotation cropping management compared to those in a conventional farming system (CFS) with chemical fertilizers, pesticide and herbicide from May 2009 to October 2010 in an upland field. With the exception of fungi, populations of aerobic bacteria, Gram-negative bacteria, and Bacillus spp. were higher in the OFS soil during soybean-growing stages. In addition, populations of aerobic bacteria, Gram-negative bacteria, and Bacillus spp. in the OFS soil were nearly two times more than those in the CFS soil on reproductive growth stages. Our findings suggested that Bacillus spp. should be considered as responsible factor for microbial population differentiation observed between the OFS and the CFS in upland fields.

• The Korean Journal of Mycology
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• v.18 no.3
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• pp.164-177
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• 1990

This study was carried out to obtain some useful data for increasing an effective ginseng production. There was a direct relationship (r=0.2645) between spore germination of Fusarium solani and soil pH, and (r=0.315) between Cylindrocarpon destructans and soil pH. On the other hand, there was a direct relationship (r=0.19) between relative hyphal growth of Rhizoctonia solani and soil pH. There was a direct relationship (r=0.21) between number of total bacteria and F. solani, (r=0.37) between actinomycetes and F. solani and (r=0.20) between celluloytic bacteria and F. solani. However, there was an inverse relationship (r=-0.20) between number of total fungi and F. solani. There was a direct relationship (r=0.24) between number of actinomycetes and R. solani. Each ginseng pathogen-suppressive soil screened was 40 in F. solani, 20 in C. destructans and 9 soil samples in R. solani among 146 soil samples, respectively. The mean contents of K, Ca and Mg were fairly lower in each ginseng pathogen-suppressive soil than conducive soil, whereas Na were somewhat lower. The mean contents of organic matter were over 2 times higher in each ginseng pathogen-suppressive soil than conducive soil. The mean contents of phosphate were fairly lower in F. solani and R. solani-suppressive soil than conducive soil and, on the other hand, were somewhat higher in C. destructans-suppressive soil than conducive soil. The mean soil pH was somewhat lower in each ginseng pathogen-suppressive soil than conducive soil. The mean contents of sand were about 2 times higher in each ginseng pathogen­suppressive soil than conducive soil, whereas silt and clay were somewhat lower. The microbial numbers of total bacteria, total fungi and celluloytic fungi were higher in F. solani-suppressive soil than conducive soil, whereas actinomycetes and celluloytic bacteria were lower. Each microbial number of total bacteria or total fungi indicated a significant difference (p=0.05) between F. solani­suppressive and conducive soil, and the microbial number of actinomycetes was a highly significant difference (p=0.01) between F. solani-suppressive and conducive soil. The microbial numbers of total bacteria, total fungi, actinomycetes and celluloytic fungi were higher in C. destructans-suppressive soil than conducive soil, whereas celluloytic bacteria were about 2 times lower. On the other hand, the microbial numbers of total fungi were higher in R. solani-suppressive soil than conducive soil, whereas total bacteria, actinomycetes, celluloytic bacteria and celluloytic fungi were lower. Fourteen of 16 F. solani-suppressive soils tested were suppressive to ginseng root rot, whereas fifteen of 16 C. destructans-suppressive soils were suppressive. Ginseng root rots of ginseng disease-suppressive soils were in the range of 1.0-17.4% in F. solani-suppressive soil and 0.2-20.4% in C. destructans-suppressive soil, respectively.

• Journal of Microbiology
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• v.40 no.4
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• pp.274-281
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• 2002

The competitive quantitative PCR method targeting pcbC gene was developed for monitoring 4-chlorobiphenyl(4CB)-degrading bacteria, Pseudomonas sp. strain DJ-12, in soil microcosms. The method involves extraction of DNA from soil contaminated with 4CB, PCR amplification of a pcbC gene fragment from the introduced strain with a set of strain-specific primers, and quantification of the elec-trophoresed PCR product by densitometry. To test the adequacy of the method, Pseudomonas sp. strain DJ-12 was introduced into both contaminated and non-contaminated soil microcosms amended with 4CB. Pseudomonas sp. strain DJ-12 was monitored and quantified by a competitive quantitative PCR in comparison with 4CB degradation and the result was compared to those obtained by using the conventional cultivation method. We successfully detected and monitored 4CB-degrading bacteria in each microcosm and found a significant linear relationship between the number of 4CB-degrading bacteria and the capacity for 4CB biodegradation. The results of DNA spiking and cell-spreading experiments suggest that this competitive quantitative PCR method targeting the pcbC gene for monitoring 4CB- degrading bacteria appears to be rapid, sensitive and more suitable than the microbiological approach in estimating the capacity of 4CB biodegradation in environmental samples.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1130-1134
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• 2005

To monitor the possibility of horizontal gene transfer between transgenic potato and bacteria in the environment, the gene flow from glufosinate-tolerant potato to bacteria in soils was investigated. The soil samples treated with the leaf tissue of either glufosinate-tolerant or glufosinate-sensitive potato were subjected to PCR and Southern hybridization to determine possible occurrence of glufosinate-resistant soil bacteria and to detect the bar (phosphinothricin acetyltransferase) gene, conferring tolerance to glufosinate. The bar gene was not detected from genomic DNAs extracted at different time intervals from the soil samples, which had been treated with the leaf tissue of either transgenic or non-transgenic potato for 2 to 8 weeks. In addition, the level of glufosinate-resistant bacteria isolated from the soil samples treated with the leaf tissue of transgenic potato was similar to that of the samples treated with non-transgenic potato after 4 months of incubation at $25^{\circ}C$. The bar gene was not detected in the genomic DNAs extracted from colonies growing on the plate containing glufosinate, indicating that the bacteria could acquire the resistant phenotype to glufosinate by another mechanism without the uptake of the bar gene from glufosinate-tolerant potato.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.3
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• pp.492-497
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• 2011

Soil management for orchard depends on the effects of soil microbial activities. The present study evaluated the soil microbial community of 25 orchard in Gyeongnam Province by fatty acid methyl ester (FAME) method. The average concentrations in the orchard soils were $332nmol\;g^{-1}$ of total FAMEs, $94nmol\;g^{-1}$ of bacteria, $46nmol\;g^{-1}$ of Gram-negative bacteria, $42nmol\;g^{-1}$ of Gram-positive bacteria, $4.8nmol\;g^{-1}$ of actinomycetes, $54nmol\;g^{-1}$ of fungi, and $9.1nmol\;g^{-1}$ of arbuscular mycorrhizal fungi. In addition, sandy loam soils had significantly low ratio of cy19:0 to 18:$1{\omega}7c$ compared with that of loam soils (p<0.05), indicating that microbial stress decreased. The average soil microbial communities in the orchard soils were 28.1% of bacteria, 15.9% of fungi, 13.6% of Gram-negative bacteria, 12.5% of Gram-positive bacteria, 2.8% of arbuscular mycorrhizal fungi, and 1.4% of actinomycetes. The soil microbial community of Gram-negative bacteria in peach cultivating soils was significantly higher than that of pear cultivating soils (p<0.05).

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.582-592
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• 2012

Microorganisms present in the rhizosphere soil plays a vital role in improving the plant growth and soil fertility. Many kinds of fertilizers including chemical and organic has been approached to improve the productivity. Though some of them showed significant improvement in yield, they failed to maintain the soil properties. Rather they negatively affected soil eventually, the land became unsuitable for agricultural. To overcome these problems, microorganisms have been used as effective alternative. For past few decades, plant growth promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) have been used as effective inoculants to enhance the plant growth and productivity. PGPR improves the plant growth and helps the plant to withstand biotic and abiotic stresses. AM fungi are known to colonize roots of plants and they increase the plant nutrient uptake. Spore associated bacteria (SAB) are attached to spore wall or hyphae and known to increase the AMF germination and root colonization but their mechanism of interaction is poorly known. Better understanding the interactions among AMF, SAB and PGPR are necessary to enhance the quality of inoculants as a biofertilizers. In this paper, current knowledge about the interactions between fungi and bacteria are reviewed and discussed about AMF spore associated bacteria.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.5
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• pp.342-347
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• 2008

Phosphate soubilized by microbes can be easily absorbed by plant as the element diffuses into soil solution. The microbes related to phosphate solubilizing activity are affected by the soil amendments such as rice straw compost, and lime. This study was performed to evaluate the effect of amendments to phosphate solubilizer in rice paddy soils. Available phosphate concentration was increased with the ratio of phosphate-solubilizing bacteria to aerobic bacteria in the rice paddy soils. The ratio was high in the plots applied with lime, silicate, and rice straw compost. Phosphate-solubilizing bacteria isolated from the soil were Aquasipirillum, Arthrobacter, Bacillus, Flavobacterium, Micrococcus and Micromonospora, Pseudomonas species. The highest dominant bacterial species was Pseudomonas, and Bacillus was followed.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.6
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• pp.103-110
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• 2019

The purpose of this study is to investigate the reaction mechanism of soil and bacteria solution by various mixing ratios. For this purpose, in order to understand the reaction mechanisms of microorganisms and weathered granite soil, the tests were carried out under various mixing ratios additives such as soil, bacteria solution, $Ca(OH)_2$ and fixture. The test results from this study are summarized as follows. Firstly, the reaction between the bacteria solution and fixture produced a precipitate called vaterite, a type of silicate and calcium carbonate. Secondly, as a result of SEM analysis, the resulting precipitates generated from the test results using the specimens with various mixing ratios except SW condition and the irregular spherical microscopic shapes were formed in the size of $150{\mu}m$ to $20{\mu}m$. In addition, it can be seen that the bacteria solution and the fixture reacted between the granules to form an adsorbent material layer on the surface, and the microorganisms had a biological solidifying effect when the pores are combined into hard particles. Finally, The XRD analysis of the sediment resulting from the reaction between the microorganism and the deposit control agent confirmed the presence of a type of calcium carbonate ($CaCO_3$) vaterite, which affects soil strength formation, as well as silicate($SiO_2$).