• Journal of Species Research
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• v.7 no.1
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• pp.13-23
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• 2018

In 2016, as a part of the research program 'Survey of Korean Indigenous Species', diverse environmental samples were collected from various sources of freshwater, seawater, soil, wetland, reclaimed land, sand, pine forest, plant root, ginseng field, solar saltern, and caves. Thousands of bacterial strains were isolated from the diverse samples and identified based on 16S rRNA gene sequence analyses. The present study, as a phylogenetic subset of the primary research program, reports 24 unrecorded bacterial species in Korea that belong to the orders Rhizobiales and Sphingomonadales in the class Alphaproteobacteria. Based on the high 16S rRNA gene sequence similarities (>98.8%) and formation of a robust phylogenetic clade with the closest type species, it was determined that each strain belonged to each independent and predefined bacterial species. There is no official report that these 24 bacterial species have been described in Korea; therefore, 10 species of nine genera in the order Rhizobiales and 14 species of seven genera in the order Sphingomonadales are described for unreported alphaproteobacterial species in Korea. Gram reaction, colony and cell morphology, biochemical properties, and isolation sources are also provided in the species description section.

• Journal of the Korean Society of Food Science and Nutrition
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• v.15 no.4
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• pp.24-31
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• 1986

A methanol-assimilating yeast for the production of Single Cell Protein was isolated from the soil and identified. Methanol as a sole carbon source was used in this study. The strain was identified as Candida boidinii which grew best at the initial concentration of methanol at 2% , with the addition of 0.5% methanol at every 12 hours, The Single Cell Protein production was maximal after 72 hours of incubation at pH 5.0, $30^{\circ}C$. Thiamin and biotin were stimulated the growth of this yeast at the levels of $1000{\mu}g/{\ell}$ and $10{\mu}g/{\ell}$respectively.

• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1498-1503
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• 2007

To identify novel crystal proteins, Bacillus thuringiensis 2385-1 was isolated from Korean soil samples and characterized. The H-serotype of 2385-1 was identical to that of subsp. kenyae (H4a4c), and its crystal toxin was bipyramidal-shaped. However, 2385-1 showed a much higher toxicity towards Plutella xylostella and Spodoptera exigua larvae than subsp. kenyae. In addition, the crystal protein profile and plasmid DNA pattern of 2385-1 differed from those of subsp. kenyae. To verify the crystal protein gene types of 2385-1, a PCR-RFLP analysis was performed, and the results revealed that 2385-1 contained two novel cry1-type crystal protein genes, cryl-5 and cry1-12, in addition to the crylJal gene. The deduced amino acid sequences of cryl-5 and cry1-12 showed a 97.9% and 75.7% sequence similarity with the CrylAb and CrylJa crystal proteins, respectively. Among the novel crystal proteins, Cry1-5 showed a high toxicity towards P. xylostella and S. exigua larvae. In conclusion, B. thuringiensis 2385-1 is a new isolate in terms of its gene types, and should be a promising source for an insecticide to control lepidopteran larvae.

• Microbiology and Biotechnology Letters
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• v.14 no.3
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• pp.239-244
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• 1986

To develop the potential use as new host strain for gene cloning, alkaline-tolerant isolates from soil were examined for amylase activity, protease activity, antimicrobial activity and transformability by using plasmid pUB 110. Of these strains, one was selected and identified as Bacillus sp. YA-14. in the enzymatic properties of Bacillus sp. YA-14 the optimal conditions for the reaction of amylase and protease were at pH 0.8 and pH 7.5 respectively. The antimicrobial activity of Bacillus sp. YA-14 was also found. For the transformation, Bacillus sp. YA-14 was cultured to late logarithmic growth phase ai 37$^{\circ}C$ in modified SPI medium (pH 8.0) containing 0.4% MgSO$_4$. The presence of pUB 110 plasmid DNA in transformants was confirmed by electrophoresis and stably maintained in the new host.

• Microbiology and Biotechnology Letters
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• v.17 no.3
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• pp.207-212
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• 1989

Cultural conditions for $\alpha$-D-Glucosidase Inhibitor production from Streptomyces sp. YS-221-B isolated from soil arid identified as Streptomyces flauovirens or a subspecies of it were investigated. When the strain was cultured in a flask containing 2% glucose, 0.3% asparagine, 0.0002% riboflavin, 0.05% $K_2$HPO$_4$, 0.1% MgSO$_4$.7$H_2O$, 0.05% NaCl, pH 8.0 at 3$0^{\circ}C$, maximum production of the inhibitor was obtained after 8-9 days of cultivation. Sugar alcohols such as mannitol, i-inositol, erythritol as carbon sources, asparagine and beef extract as nitrogen sources were favorable for inhibitor production. Among vitamins, riboflavin, p-aminobenzoic acid, pyridoxamine and folic acid promoted the production of inhibitor, but depressed by the addition of hesperidine, and also depressed by cobalt, lithium and ferrous salts.

• Microbiology and Biotechnology Letters
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• v.32 no.4
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• pp.312-316
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• 2004

In oder to select the powerful rhizophere-dorminatable biocontrol agent, we had isolated an indigenous antagonistic bacterium which produced antibiotic and siderophore from a disease suppressive local field soil of Gyungsan, Korea. And we could select the Pseudomosp. 4059 which can strongly antagonize against Fusarium oxysporum and Phytophthora capsici by two kinds of antifungal mechanism that can be caused by the antibiotic of Phenazin, a siderophore and a auxin like subThe selected strain was identified as Pseudomonas fluorescens (biotype A) 4059 by biochemical tests, API $\textregistered$ test, MicroLog TM system and 16S rDNA analysis. The selected antagonistic microorganism, Pseudomosp. 4059 had an antifungal mechanism of antifungal antibiotic and sidrophore. And we were confirmed the antagonistic activity of P fluorescens 4059 with in vitro antifungal test against Phytophthora capsici and in vivo by red-pepper.

• The Plant Pathology Journal
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• v.34 no.4
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• pp.286-296
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• 2018

Maintenance of a beneficial microbial community, especially in the rhizosphere, is indispensable for plant growth and agricultural sustainability. In this sense, plant growth-promoting rhizobacteria (PGPR) have been extensively studied for their role in plant growth promotion and disease resistance. However, the impact of introducing PGPR strains into rhizosphere microbial communities is still underexplored. We previously found that the Proteus vulgaris JBLS202 strain (JBLS202) promoted growth of Kimchi cabbage and altered the relative abundance of total bacteria and Pseudomonas spp. in the treated rhizosphere. To extend these findings, we used pyrosequencing to analyze the changes in bacterial communities in the rhizosphere of Kimchi cabbage after introduction of JBLS202. The alterations were also evaluated by taxon-specific realtime PCR (qPCR). The pyrosequencing data revealed an increase in total bacteria abundance, including specific groups such as Proteobacteria, Acidobacteria, and Actinobacteria, in the treated rhizosphere. Time-course qPCR analysis confirmed the increase in the abundance of Acidobacteria, Actinobacteria, Alphaproteobacteria, and Betaproteobacteria. Furthermore, genes involved in nitrogen cycling were upregulated by JBLS202 treatment indicating changes in ecological function of the rhizosphere soil. Overall, these results indicate that introduction of JBLS202 alters both the composition and function of the rhizosphere bacterial community, which can have direct and indirect effects on plant growth. Therefore, we propose that long-term changes in bacterial composition and community-level function need to be considered for practical use of PGPRs.

• Journal of Life Science
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• v.12 no.2
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• pp.200-207
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• 2002

This study was carried out to isolate of antagonistic bacterium against Pythium ultimum and Rhizoctonia solani AG-4, causal pathogens of vegetables damping-off. Total of 600 strains were isolated from soil and plait roots. The isolates were screened for antagonism against Pythium ultimum and Rhizoctonia solani AG-4. One strain, named YJ-37, was sellected for detained study among those microoganisms screened. It was identified as Bacillus ehimensis based on morphological and physiological characterisitics according to the Bergey's mannual of systematic bacteriology, Sherlock system of Microbial ID Inc. and 16S rDNA sequences methods. Furthermore Bacillus ehimensis YJ-37 showed antifungal activities against Alternaria altrata, Collectotrichum gloeosporioides, Didymella bryoniae, Fusarium moniliforme, Fusarium oxysporum, F. oxysporum cucumerinum, F. oxysporum niveum, Gloeosporium sp., Glomerella sp., G. cingulata, G. lagenaria, Penicillium digitatum, P. italicum, Phytophthora capsici, Sclerotinia sclerotiorum, and Stemprhylium solani.

• Applied Biological Chemistry
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• v.40 no.3
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• pp.184-188
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• 1997

A bacterial strain, producing extracellular inulin fructotransferase which converts inulin into di-D-fructofuranose 1,2':2,3' dianhydride(DFA III), was isolated from soil and presumed as Bacillus sp.. The highest production of the enzyme was obtained by using medium containing Jerusalem artichoke extract as carbon source, peptone as organic nitrogen source, and $NH_4H_2PO_4$, as inorganic source. Under optimum condition, the enzyme activity of the culture broth supernatant reached maximal 2.61 units/ml after cultivation for 45 hrs.

• The Plant Pathology Journal
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• v.23 no.4
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• pp.239-244
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• 2007

MicroTom is a miniature tomato plants with various properties that make it as a model system for experiments in plant molecular biology. To extend its utility as a model plant to study a plant - bacterial wilt system, we investigated the potential of the MicroTom as a host plant of bacterial wilt caused by Ralstonia solanacearum. We compared the disease progress on standard tomato and MicroTom by two inoculation methods, root dipping and soil drenching, using a race 1 strain GMI1000. Both methods caused the severe wilting on MicroTom comparable to commercial tomato plant, although initial disease development was faster in root dipping. From the diseased MicroTom plants, the same bacteria were successfully reisolated using semiselective media to fulfill Koch's postulates. Race specific and isolate specific virulence were investigated by root dipping with 10 isolates of R. solanacearum isolated from tomato and potato plants. All of the tested isolates caused the typical wilt symptom on MicroTom. Disease severities by isolates of race 3 was below 50 % until 15 days after inoculation, while those by isolates of race 1 reached over 50% to death until 15 days. This result suggested that MicroTom can be a model host plant to study R. solanacearum - plant interaction.