• Research in Plant Disease
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• v.12 no.3
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• pp.189-196
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• 2006

Crown gall on lower stem of weeping fig(Ficus benjamina Roxb.) was first observed at Daejon in 2003. Tumors were about 15 cm in size and semi-round with rough surface texture of dark brown color. Two virulent isolates among ten bacteria isolated from the tumor tissues were characterized. Their colonies were convex, glistening, circular with an entire edge, and white or tannish cream in color on potato dextrose agar supplemented with 0.5% $CaCO_3$. They were rod shape with peritrichous flagellae, gram-negative, aerobic growth, oxidase-positive, and grew on D1M agar. The isolates were identified as Agrobacterium larrymoorei and A. tumefaciens based on biochemical and physiological characteristics, fatty acid profiles and substrate utilization patterns. Seedlings of some host plants excepting grapevine produced typical galls two to three weeks after inoculation with cell suspensions of the virulent strains. This is the first report on crown gall of weeping fig in Korea.

• Korean journal of food and cookery science
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• v.17 no.3
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• pp.218-223
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• 2001

This study was conducted to evaluate the functional properties of onion, rosemary and thyme extracts which are the ingredients of onion Kimchi. Onion extract showed a significant difference in antioxidative effect based on peroxide value and thiocyanate method. Antioxidative activity of rosemary extract was similar to those of BHA and BHT. but thyme extract did not show any antioxidative effect.. Onion, rosemary, and thyme extracts showed antimicrobial activities against gram positive bacteria but onion and thyme extracts did not against E. coli, Candida, and molds. Rosemary extract demonstrated a strong activity against L. plantarum which is a major lactobacillus in Kimchi fermentation, and Micrococcus luteus. Onion, rosemary, and thyme extracts showed an effect or hangover relief effect by lowering the alcohol concentration of blood in rat. Blood pressure of the male spontaneous hypertensive rat was suppressed by onion extract after 3 days of feeding, but rosemary and thyme extracts were not effective for lowering blood pressure.

• Fisheries and Aquatic Sciences
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• v.23 no.8
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• pp.20.1-20.18
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• 2020

Background: Olive flounder, Paralichthys olivaceus, is an economically important aquaculture species in Korea. Olive flounders have been heavily damaged by streptococcal infections every year and are treated with antibiotics. However, antibiotic abuse is causing the emergence of resistant strains, and to overcome this, research has shown that new antibiotics must be applied. Tylosin is a relatively safe antibiotic and has good activity against Gram-positive bacteria and mycoplasma. We studied the therapeutic effects and side effects of tylosin on Streptococcus parauberis-infected olive flounder. Methods: After artificial infection of olive flounder with S. parauberis SPOF18J3, an appropriate dose of tylosin was confirmed by intramuscular injection (I.M.) at 2.5, 5, 10, and 15 mg/kg, and oral administration at 10 and 20 mg/kg. After I.M. and oral administration dosing of tylosin, side effects were confirmed by serological analysis, histopathological analysis, and median lethal dose (LD₅₀) analysis at both an appropriate concentration and a high concentration. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Tukey's test (p < 0.05). Results: The appropriate I.M. and oral administration concentration of tylosin administered to olive flounder infected with S. parauberis SPOF18J3 was found to be 10 mg/kg. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were showed not significantly different between the control group and the experimental groups. The histopathologic results showed mild inflammatory responses in muscle and tubular vacuolization and tubular atrophy appeared, but there were no significant differences between the groups. The LD₅₀ was confirmed to be 461 mg/kg. Conclusion: In this study, an effective treatment method was provided by verifying the treatment effects and side effects of tylosin in olive flounder infected with S. parauberis, which can be applied directly to aquaculture sites. In addition, these results may be used as a reference for evaluation required upon request to obtain approval for tylosin antibiotics as fishery antibiotics in Korea. After approval, it is possible that a fishery disease manager will be able to prescribe and sell the antibiotic tylosin.

• The Korean Journal of Mycology
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• v.40 no.2
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• pp.118-123
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• 2012

In order to develop environment friendly fungicide for the control of citrus green mold (Penicillium digitatum) using endophytic bacteria, the 21 bacterial isolates were isolated from citrus leaves in seven different orchards in Jeju Province. Among the 21 bacterial isolates, 5 bacterial isolates presented antifungal activity against green mold pathogen P. digitatum. The CB3 isolate, which showed the most strong antagonistic effect, was selected through opposite culture against the pathogen. The rod-shaped, gram-positive bacterium CB3 was identified as Bacillus velezensis based on morphological, physiological characteristics, 16S rDNA, and gyr A gene sequence analysis. The isolate CB3 showed strong antifungal activity against two citrus postharvest pathogen P. digitatum. Citrus fruits were treated by wound inoculation with P. digitatum pathogen, and the control efficacy of CB3 culture broth was 66.7% ($1{\times}10^8$ cfu/ml). In conclusion, The stability of CB3 and its strong antifungal activity also lead us to believe that it has potential for application as an environment friendly biological control agent.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.210-215
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• 2014

Pseudomonas nitroreducens TX1 was isolated from a rice field drainage in Taiwan. The bacterium is of special interest because of its capability to use a group of nonionic surfactants such as alkylphenol polyethoxylates even at high concentrations as a sole carbon source. In this study, a small cryptic circular plasmid, pTX1, was characterized from P. nitroreducens TX1. It is 2,286 bp in length with a GC content of 63.3% and harbors three open reading frames, $Rep_{pTX1}$ and functionally unidentified ORF1 and ORF2. The predicted $rep_{pTX1}$ gene product is homologous to Rep proteins of plasmids belonging to the pC194/pUB110 family, which is predominantly found in Gram-positive bacteria and is known to replicate by the rolling-circle mechanism. The copy number of pTX1 was estimated to be about 150 in each cell. Based on the genetic fingerprints and comparison with other plasmids, it is concluded that pTX1 replicates by a rolling circle mechanism which is rarely found for Pseudomonas plasmids.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.261-266
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• 1979

This experiment was carried out to evaluate the sanitary quality of cultured vegetables and to check the removing rate of bacteria by treating methods such as washing with tap water or commercial detergent, or blanching. Samples collected from farm land located at Busan suburbs and markets were Fragaria chiloensis var. ananasa, Lycopersicum esculentum, Capsium longum, Cucumis sativus, Lactuca scariola var. sativa leaf of Perilla frutescens var, japonica, Oananthe stolonifera and Allium odoium. Fecal coliform MPN was ra god from less than 30 to 430,000 per 100 grams of samples examined while plate count was $7.2\times10^3\;to\;2.2\times10^7$ per gram. Usually contamination rate of fecal coliform of leaf vegetal)les was much higher than that of fruit vegetables. Removing rate of bacterial density of vegetables by washing three times with tap water was about $70\%$ in fruit vegetables, about $20\%$ in leaf vegetables but it was about $80\%$ in leaf vegetables by washing with a commercial detergent. Sirvival rate of viable cell count of leaf vegetables was less than $0.1\%$ after blanching for one minutes in boiling tap water, Composition of coliform was $18\%$ Escherichia coli group, $22\%$ Citrobacter freundii group and $60\%$ Klebsiella aerogenes group, among Escherichia coli, type I being $16\%$ in total. The coliform detection from BGLB gas positive tubes being planted with various vegetables was about $80\%$ in the result of IMViC reaction.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.26-32
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• 2013

Butanol-resistant bacteria were isolated from butanol solvent. The cell growth of isolated strains declined with increasing concentrations of butanol, and isolated strain BRS02 displayed more resistance to 12.5 g/L of butanol than other isolated strains. In addition, strain BRS251, which was resistant to even higher concentrations of butanol, was developed by the mutation of BRS02 using UV. BRS251 could grow in LB medium containing up to 17.5 g/L of butanol, 32.5 g/L of propanol, or 6 g/L of pentanol, whereas the control strain Escherichia coli was found to be tolerant to 7.5 g/L of butanol, 20 g/L of propanol, or 2 g/L of pentanol. The isolated BRS02, a Gram(+) bacterium seen to have a cocci form under the microscope, grew in 6.5% NaCl. According to biochemical tests, BRS02 can metabolize and produce acid with D-galactose, D-maltose, D-mannitol, D-mannose, methyl-${\beta}$-Dglucopyranoside, D-ribose, sucrose, or D-trehalose, as carbon sources. Also, this strain showed resistance to bacitracin, vibriostatic agent O/129, and optochin, alongside positive activities for arginine dihydrolase, ${\alpha}$-glucosidase, and urease. The BRS02 strain was identified as Staphylococcus sp. by analyses of the 16S rRNA gene, phylogenetic tree, and biochemical tests.

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.689-699
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• 2020

Brevibacillus brevis GZDF3 is a gram-positive, plant growth-promoting rhizosphere bacterium (PGPR) isolated from the rhizosphere soil of Pinellia ternata (an important herb in traditional Chinese medicine). The GZDF3 strain produces certain active compounds, such as siderophores, which are the final metabolite products of non-ribosomal peptide synthetase (NRPS) and independent non-ribosomal peptide synthetase (NIS) activity. With the present study, we attempted to investigate the siderophore production characteristics and conditions of Bacillus sp. GZDF3. The antibacterial activity of the siderophores on pathogenic fungi was also investigated. Optimal conditions for the synthesis of siderophores were determined by single factor method, using sucrose 15 g/l, asparagine 2 g/l, 32℃, and 48 h. The optimized sucrose asparagine medium significantly increased the production of siderophores, from 27.09% to 54.99%. Moreover, the effects of different kinds of metal ions on siderophore production were explored here. We found that Fe³⁺ and Cu²⁺ significantly inhibited the synthesis of siderophores. The preliminary separation and purification of siderophores by immobilized-metal affinity chromatography (IMAC) provides strong antibacterial activity against Candida albicans. The synergistic effect of siderophores and amphotericin B was also demonstrated. Our results have shown that the GZDF3 strain could produce a large amount of siderophores with strong antagonistic activity, which is helpful in the development of new biological control agents.

• Applied Biological Chemistry
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• v.42 no.2
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• pp.99-104
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• 1999

Soil actinomycetes of 703 strains were isolated from 25 sampling points in Cheju Island using 4 different media. Arginine glycerol salts agar containing soil extract was found to be the best medium for the isolation of soil actinomycetes. Soil samples from pasture land showed higher population and diversity of the actinomycetes than those from citrus field, forest, island, hill or valley. When the antibacterial activity of the 526 isolates was tested against three bacterial strains, Escherichia coli, Staphylococcus aureus and Pseudomonas solanacearum the frequency of the isolates with antibacterial activity varied much depending upon the media used for isolation and cultivation. BL106Ba, one of the 10 isolates that showed antibacterial activity against all the above 3 test strains, was chosen based upon the pH and heat stability of its antibacterial metabolites, and was identified as Streptomyces sp. based upon its cultural, morphological and physiological characteristics. The partially purified white crystalline substance obtained from the culture supematant of BL1063a through cation exchange chromatography(AG MP-50) and three times consecutive gel filtration(Sephadex G-10) showed high antimicrobial activity against gram positive and negative bacteria, but low activity against yeasts. The partially purified substance was found to contain at least four different compounds with antibacterial activity by both thin layer chromatography and high performance liquid chromatography.

• Journal of Life Science
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• v.18 no.1
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• pp.109-113
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• 2008

For useful basic data in new ascidian processed products, this study investigated and compared the biological activities of two ascidians, Styela clava and Styela plicata, in two conditions with fresh one and cooking one at $100^{\circ}C$ for 10 min. By fresh state, Styela clava (8.46 mg/ml) had higher activity than Styela plicata (13.67 mg/ml) in the antioxidative assay ($EDA_{50}$), whereas Styela plicata (10.54 mg/ml) had higher than Styela clava (12.05 mg/ml) after cooking. Particularly the antioxidative activity of Styela plicata increased 1.3 times after cooking. Fresh Styela clava had antimicrobial activity against Bacillus subtilis, B. cereus, E. coli, whereas the activity appeared against E. coli only after cooking. However, antimicrobial activity in Styela plicata appeared against 4 gram positive bacteria (B. subtilis, B. cereus, S. aureus and L. monocytogenes) and E. coli, regardless of concentration level (1,000-1,500 ppm) and with/without cooking. ACE inhibitory activity was not observed in the samples. By cooking, the level of fibrinolytic activity increased to 1.79 from 1.24 plasmin unit/ml in Styela plicata, whereas the level decreased to 1.55 from 1.62 in 5tyela clava.