• Journal of fish pathology
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• v.7 no.2
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• pp.105-112
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• 1994

A new bacterial infection occurred among the cultured Korean catfish, Silurus asotus, in Chunbuk prefecture, Korea, 1993. This disease produced about 30% mortality in the fish for 4 months. The diseased fish was swimming listless at the water surface with head up and tail down, sometimes spinnig in circles. The most outstanding clinical sign was ulceration on the skull and at the base of the pectoral fins. The causative organism was isolated from the brain, kidney, spleen and liver of diseased fish, and identified as Edwardsiella icaluri by the biochemical and biophysical characteristics. After intraperitoneal innoculaton of the isolate, the pathogenicity was proved positive for Korean catfish, S. asotus, and channel catfish, Ictalurus punctatus, but negative for carp, Cyprinus carpio.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1071-1076
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• 1999

This study was carried out to isolate the colonies of dominant fermented bacteria from Kimchi (Korean native fermented foodstuffs) and investigate their inhibitory potentials on mutagenesis and carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) as direct carcinogen. For this purpose, single cell gel electrophoresis technique (SCGE assay, or comet assay) which is a sensitive and rapid technique for detecting the presence of DNA strand breaks in individual cells was used. DNA damages of Kimchi isolates were compared with that of the positive control, MNNG. Among 3 isolates from Tongbaechu Kimchi, two isolates B-1 and B-2 showed antigenotoxicities (p<0.01). All 4 isolates from Yulmu Kimchi had antigenotoxicities (p<0.05). Also, 3 of 5 isolates from Chonggak Kimchi and 2 of 9 isolates from Kaktugi were antigenotoxic (p<0.05 and p<0.01, respectively).

• Journal of Life Science
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• v.19 no.3
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• pp.397-402
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• 2009

To isolate bacteria secreting protease, which can dissolve fibrin efficiently, we prepared chunggukjang using rice straw and isolated, preliminarily, approximately 100 bacterial stains. Their capabilities to dissolve milk protein as well as fibrin included in media were then examined and finally, five strains named J1 - J5 were selected. Among them, J-4, which is close to bacillus subtilis, showed highest activity for fibrin dissolution. Proteases secreted from the J-4 strain were partially purified from culture supernatant using DEAE-sepharose column chromatography and identified with SDS-polyacrylamide gel electrophoresis. Three proteins were subjected to analysis with MALDI-TOF and PMF (Peptide Mass Fingerprinting). 41.9 kDa protein was identified as a neutral protease. On the other hand, 45 kDa protein turned out to be bacillopeptidase F, with a molecular mass of 91.7 kDa, indicating that partially purified peptide is a degradation product.

• 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.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.223-225
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• 2007

Many plant growth-promoting rhizobacteria (PGPRs) have been known for beneficial effects on plants including biological control of soilborne pathogens, induced systemic resistance to plant pathogens, phytohormone production, and improvement of nutrient and water uptake of plants. We developed a simple and rapid method for screening potential PGPR, especially phytohormone producing rhizobacteria, or for analyzing their functions in plant growth using cucumber seedling cuttings. Surface-sterilized cucumber seeds were grown in a plastic pot containing steamed vermiculite. After 7 days of cultivation, the upper part 2 cm in length of cucumber seedling, was cut and used as cucumber cuttings. The base of cutting stem was then dipped in a microcentrifuge tube containing 1.5ml of a bacterial suspension and incubated at $25^{\circ}C$ with a fluorescent light for 10 days. Number and length of developed adventitious roots from cucumber cuttings were examined. The seedling cuttings showed various responses to the isolates tested. Some isolates resulted in withering at the day of examination or in reduced number of roots developed. Several isolates stimulated initial development of adventitious roots showing more adventitious root hair number than that of untreated cuttings, while some isolate had more adventitious root hair number and longer adventitious roots than that of untreated control. Similar results were obtained from the trial with rose cuttings. Our results suggest that this bioassay method may provide a useful way for differentiating PGPR's functions involved in the development of root system.

• BMB Reports
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• v.44 no.5
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• pp.335-340
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• 2011

In this study, we attempted to isolate novel mast cell-stimulating molecules from Staphylococcus aureus. Water-soluble extract of S. aureus cell lysate strongly induced human interleukin-8 in human mast cell line-1 and mouse interleukin-6 in mouse bone marrow-derived mast cells. The active molecule was purified to homogeneity through a $C_{18}$ reverse phase HPLC column. By determination of its structure by MALDITOF and $^1H$- and $^{13}C$-NMR, adenosine was revealed to be responsible for the observed cytokine induction activities. Further studies using 8-sulfophenyl theophylline, a selective adenosine receptor blocker, verified that purified adenosine can induce interleukin-8 production via adenosine receptors on mast cells. Moreover, adenosine was purified from S. aureus-engulfed RAW264.7 cells, a murine macrophage cell line, used to induce phagocytosis of S. aureus. These results show a novel view of the source of exogenous adenosine in vivo and provide a mechanistic link between inflammatory disease and bacterial infection.

• Journal of Species Research
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• v.7 no.1
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• pp.36-49
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• 2018

During a study to discover indigenous prokaryotic species in Korea in 2016, a total of 42 actinobacterial isolates were recovered from various environmental samples collected from natural cave, squid, sewage, sea water, trees, droppings of birds, freshwater, eelgrass, mud flat, sediment and soil. On the basis of a tight phylogenetic clade with the closest species and high level of 16S rRNA gene sequence similarity, it was shown that each isolate was assigned to independent and previously described bacterial species which were assigned to the phylum Actinobacteria. The following 42 species have not been reported in Korea: eight species in two genera n the order Corynebacteriales, 26 species of 16 genera in the Micrococcales, one species of one genus in the Micromonosporales, one species of one genus in the Propionibacteriales, four species of two genera in the Streptomycetales and two species of two genera in the Streptosporangiale. Cell morphology, Gram staining reaction, colony colors and features, the media and conditions of incubation, physiological and biochemical characteristics, origins of isolation and strain IDs of 42 unrecorded actinobacterial species are presented in the species description.

• Journal of the Korean Applied Science and Technology
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• v.27 no.2
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• pp.114-122
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• 2010

Hydroxy fatty acids have gained important attentions because of their special properties such as higher viscosity and reactivity compared to non-hydroxy fatty acids. The new bacterial isolate Pseudomonas aeruginosa (PR3) had been well studied to produce mono-, di-, and tri-hydroxy fatty acids from different unsaturated fatty acids. Of those hydroxy fatty acids, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD) was produced with high yield from oleic acid by P. aeruginosa PR3. Mostly, the substrates used for the production of hydroxy fatty acid by microorganisms were free fatty acids or synthetic lipids. However, it is highly plausible to use vegetable oils containing oleic acid such as olive oil for DOD production by P. aeruginosa PR3. As a first step to address the utilization of olive oil as a substrate for DOD production, we tried to determine the effect of vessel type on DOD production from olive oil by P. aeruginosa PR3. Of two different flask types of normal flask and baffled-flask, baffled-flask was highly effective for DOD production with all the media tested. Maximum increase of productivity by baffled-flask represented 221% with the medium supplemented with whey powder instead of lactose. Results from this study demonstrated that vessel type and medium composition could be both significant factors for DOD production from olive oil by P. aeruginosa PR3.

• Applied Biological Chemistry
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• v.43 no.2
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• pp.81-85
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• 2000

Screening was performed to isolate biopolymer-producing microorganisms from natural sources. The bacteriological characteristics of this strain and physicochemical properties of the biopolymer produced were investigated. The bacterial strain was identified as a Bacillus coagulans. Crude biopolymer treated with ethanol and actone was purified to fraction I and II by ion exchange chromatography and gel chromatography (Shephadex G-100 and Shepharose CL-2B). Analysis of chemical composition and various color reaction revealed that the polymer is composed of amino acids. It was confirmed that fraction II is a homopolymer of glutamic acid and fraction I is a homopolymer of lysine by analysis data of amino acid analyzer, GC and IR.

• The Plant Pathology Journal
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• v.30 no.3
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• pp.288-298
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• 2014

We examined the efficacy of a bacterium for biocontrol of the root-knot nematode (RKN) Meloidogyne hapla in carrot (Daucus carota subsp. sativus) and tomato (Solanum lycopersicum). Among 542 bacterial isolates from various soils and plants, the highest nematode mortality was observed for treatments with isolate C1-7, which was identified as Bacillus cereus based on cultural and morphological characteristics, the Biolog program, and 16S rRNA sequencing analyses. The population density and the nematicidal activity of B. cereus C1-7 remained high until the end of culture in brain heart infusion broth, suggesting that it may have sustainable biocontrol potential. In pot experiments, the biocontrol efficacy of B. cereus C1-7 was high, showing complete inhibition of root gall or egg mass formation by RKN in carrot and tomato plants, and subsequently reducing RKN damage and suppressing nematode population growth, respectively. Light microscopy of RKN-infected carrot root tissues treated with C1-7 showed reduced formation of gall cells and fully developed giant cells, while extensive gall cells and fully mature giant cells with prominent cell wall ingrowths formed in the untreated control plants infected with RKNs. These histopathological characteristics may be the result of residual or systemic biocontrol activity of the bacterium, which may coincide with the biocontrol efficacies of nematodes in pots. These results suggest that B. cereus C1-7 can be used as a biocontrol agent for M. hapla.