• Korean Journal of Microbiology
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• v.51 no.2
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• pp.141-147
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• 2015

Four halophilic bacteria were isolated from a salt water tank of more than 25% above salinity used for production of salt. HJS1 and HJS6 strains were identified as having ${\beta}$-glucosidase producing capabilities at high salinity. ${\beta}$-Glucosidase produced from these bacterial strains showed the best activity at 56-79 U/ml in NaCl (0-5%), showing the highest ${\beta}$-glucosidase activity at NaCl 3%. A salt tolerant ${\beta}$-glucosidase can maintain at least 75% activity of the enzyme in 0-20% NaCl concentration. The 16S rRNA gene sequences of strains HJS1 and HJS6 shows 99.8% similarity with Roseivivax roseus $BH87090^T$. Those sequences were registered as AB971835 and AB971836 in the NCBI GenBank. DNA-DNA hybridization test revealed that both strains showed 90.1 to 90.3% hybridization values with R. roseus $BH87090^T$, which was the closest phylogenetic neighbor. Major Cellular fatty acids of strains HJS1 and HJS6 were $C_{16:0}$, $C_{18:1}$ ${\omega}7c$, $C_{19:0}$ cyclo ${\omega}8c$ and 11-methyl $C_{18:1}$ and the major quinone was Q-10. Their fatty acid composition and quinone were very similar to Roseivivax roseus $BH87090^T$. Meanwhile, Roseivivax roseus $BH87090^T$ did not produce any ${\beta}$-glucosidase. Based on the molecular and chemotaxonomic properties, strains HJS1 and HJS6 were identified as members of Roseivivax roseus.

• Applied Biological Chemistry
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• v.40 no.1
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• pp.85-88
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• 1997

In orther to isolate antibacterial substances from the flower of Chrysanthemum zawadskii Herbich var. latilobum Kitam., the chloroform fraction was fractionated according to the activity against B. subtilis, S. aureus and V. parahaemolyticus. Two antibacterial substances were isolated and purified by preparative TLC and recrystallization. Compound I showed activity against all the tested bacteria and compound II exhibited the activity against B. subtilis and v. parahaemolyticus except S. aureus. Compared to benzoic acid and sorbic acid which are being used as food preservatives, compounds I and II showed about five-fold stronger antibacterial activity against B. subtilis and V. parahaemolyticus. On the basis of spectrometric studies including $^1H-NMR,\;^{13}C-NMR,\;DEPT,\;^1H-^1H\;COSY,\;^{13}C-^1H\;COSY$ and Mass, compounds I and II were identified as angeloylcumambrin B and cumambrin A, respectively. This is the first report of the isolation of angeloylcumambrin B and cumambrin A from this plant.

• 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.

• Journal of Life Science
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• v.19 no.12
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• pp.1724-1730
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• 2009

The mannanase-producing bacteria, designated CS47, was isolated from the fresh feces of three horses (from a farm in Jinju National University). The isolate CS47 was facultatively anaerobic and grew at temperatures ranging from $20^{\circ}C$ to $50^{\circ}C$ with an optimal temperature of $38^{\circ}C$. The DNA G+C content of the isolate CS47 was 44 mlo%. The major fatty acids were anteiso-15:0 (39.6%), 17:0 (7.6%), and iso-15:0 (37.8%). The 16S rRNA gene sequence similarity between the isolate CS47 and other Bacillus strains varied from 93% to 98%. In the phylogenetic analysis based on these sequences, the isolate CS47 and Bacillus amyloliquefaciens clustered within a group and separated from other species of Bacillus. Based on the physiological and molecular properties, the isolate CS47 was classified within the genus Bacillus as Bacillus amyloliquefaciens CS47. The optimal pH and temperature for mannanase activity of B. amyloliquefaciens CS47 were pH 6.0 and $50^{\circ}C$, respectively. The thermal stability of mannanase from B. amyloliquefaciens CS47 is valuable when using this enzyme in industrial application.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.230-236
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• 1998

We have screened total 32 herbal drugs to find the highest activity against human cariogenic enzyme, glucosyltransferase (GTase) from the extracts of Magnoliae bark. The extracts were separated into three phases, i. e. water, n-butanol and ethylacetate according to their solvent polarity. Among them, ethylacetate fraction had approximately more than 70% of total activities, and the active principle was further isolated by prep. HPLC following silicagel column chromatography to yield single compound as white powder. The chemical structure of the compound was finally elucidated to be 4,4'-dihydroxy-3,3'-dimethoxylignan from the spectral data of FAB-MS. $^1H-\;and\;^{13}C-NMR$ spectrometries. The compound was also shown to have relatively strong antibacterial activity against ten types of cariogenic oral bacteria and one kind of Actinomyces sp.

• Journal of Life Science
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• v.20 no.5
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• pp.697-702
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• 2010

Ten farrow-finish farms participated in this seromonitoring that was conducted to investigate the porcine brucellosis situation in Korea. In total, eight (80.0%) of the 10 farms and 139 (24.0%) of 578 pigs tested showed a positive response in the Rose Bengal test (RBT). Seroprevalence levels were determined using RBT according to age; 35 (14.6%) of 239 piglets, 36 (31.3%) of 115 growing pigs, and 68 (30.4%) of 224 finishing pigs and sows were positive, respectively. All positive samples in RBT were tested with the tube agglutination test (TAT) and competitive ELISA (C-ELISA), simultaneously. Although 48 samples came up positive in the TAT, all samples tested with C-ELISA were negative. Among 26 rectal swab samples from the TAT positive-pigs, Yersinia enterocolitica O:9 was isolated from seven samples (26.9%). Therefore, we speculated that the positive reaction of RBT and TAT in this study might be induced by the serologically cross-reacting bacteria with Brucella abortus.

• Microbiology and Biotechnology Letters
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• v.30 no.2
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• pp.135-141
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• 2002

This study was carried out to isolate antagonistic bacterium against Sclerotium cepivorum causing Allium fistulosum white rot. Total of 146 strains were isolated from A. fistulosum roots. The isolates were screened for antagonism to S. cepivorum and the isolated strain No. AL-1 was selected among these bacteria. It was identified as Serratia plymuthica based on morphological and physiological characteristics according to the Bergey's mannual of systematic bacteriology and 16S rDNA sequences methods. Serratia plymuthica AL-1 showed broad spectrum of antifungal activities against plant pathogenic fungi Alternaria altrata, Colletotrichum gleosporioids, Phoma sp., Rhizoctonia solani, Sclerotinia sclerotiorum, Stemphylium solani, Fusarium oxysporium niveum but not inhibited Didymella bryoniae. When S. plymuthica AL-1 cultivated in the TSB medium containing 1％ colloidal chitin, the high molecular fraction (>10 kDa) have chitinase activity (3.2 units/ml) and the low molecular fraction (<10 kDa) have not chitinase activity. Oppositely, after heat treatment (80℃ for 30 min) of the cultivation supernatant, the high molecular fractions have not antifungal activity but the low molecular fractions have antifungal activity.

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.79-85
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• 2002

Ecological characteristics of microorganisms in tideland soils were studied by investigation of microbial diversity and population. Twenty soil samples were taken at surface, 10, 20 and 30 cm depth each. Bacteria, actinomycetes and fungi were isolated on each selective isolation medium containing different concentration of NaCl. Actinomycetes were the most isolated from soil samples taken at 10 cm depth and isolated by humic acid-vitamin (HV) medium without sea water or salt. Twenty nine strains of actinomycetes were isolated at surface soil and 74, 39, 37 strains were at 10, 20, and 30 cm depth, respectively. All these isolates were analysed and grouped by random amplified polymorphic DNA (RAPD)-PCR analysis. Many of the isolates were clustered into Microtetraspora and Pseudonocardia. Fungal isolates were highly distributed at the surface soil and isolated well on potato dextrose agar (PDA) medium with sea water. Bacterial isolates were higly distributed at surface soil and isolated well by nutrient medium without sea water or salt. Soil samples taken at 10 cm depth showed the highest microbial diversity and population.

• Clinical and Experimental Pediatrics
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• v.46 no.5
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• pp.459-466
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• 2003

Purpose : AOM is the most common bacterial URI in children. The bacteriology and antibiotic Tx of AOM in children has been studied in many countries. But, there is few study of causative pathogens and antibiotic Tx of AOM in our country. In this aspect, we performed prospective clinical study to confirm the causative pathogens and assess the clinical responses of cefprozil in AOM patients. Methods : Thirty three AOM patients enrolled in this study. Tympanocentesis for isolation of causative pathogens were performed before Tx of cefprozil. The study patients received cefprozil with dose of 15 mg/kg/bid.po/day for 10-12 days, and initially assessed the clinical response at 4-5 days after receiving cefprozil and finally at the end visit. In vitro susceptibility tests of cefprozil to isolated pathogens were done by disc diffusion method, and in vitro susceptibility tests of cefaclor and cefixime to isolated pathogens were simultaneously performed. Results : Bacterial pathogens[S. pneumoniae(10), H. influenzae(5), S. aureus(2), M. catarrhalis(1) and Group A stretococcus(1)] were isolated from 19 patients. Clinically, all patients had history of abrupt high fever except one. Tympanic perforation was dominant in pathogens isolated cases, and otalgia was significantly developed in non-pathogens isolated cases. The ages of pathogens isolated cases were usually below 2 years. Eighty four point nine percent of the patients including two cases with isolation of intermediate resistant S. pneumoniae were clinically improved. Antimicrobial in vitro activity to S. pneumoniae of cefprozil were superior than that of cefacor and cefixime. Conclusion : We confirm that bacteria has the causative role in about 60% cases, and S. pneumoniae is the most common pathogen. Clinically, there were some differences in symptoms, signs and ages between pathogens isolated and non-pathogens isolated cases. The clinical responses of cefprozil in our patients revealed similar outcomes to other countries. And we reconfirm that cefprozil may be clinically effective in cases of AOM due to intermediate resistant S. pneumoniae.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.136-144
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• 1978

A series of experiments over three years was planned for practical application of rhizobia in farms and grass lands in Korea. This is the report for the studies of the first year mainly on the isolation and characterization of rhizobial strains, and on the assessment of their nodulation abilities and nitrogen fixation capacities. 1. Total number of 88 strains for soybean group and 22 st ra ins for pea and vetch group was isolated from nodules which were taken from legumes grown in Daekwanyong, Cheju and various places in Korea. 2. Morphological and cultural characteristics of the strains were studied, and attempts were also made to investigate their antigenic properties and to demonstrate lysogenic strains in these groups. The results were : i) the isolates varied in cultural characteristics on yeast mannitol broth and agar, and in degree of congo reel absorption ; ii) similarities in their antigenic properties were found between/among the strains: G-3/G-9/D216, G-20/G-52 in soybean group; iii) no lysogeny was found in the strains of these groups. 3. Plant infection tests by test tube and bottle method in light room were carried out to elucidate the ability of the strains to nodulate specific legumes and of the capacity of such nodules to fix atmospheric nitrogen. The isolates were grouped into non- invasive, ineffective, or effective to the legumes. Those strains which produced effective nodules, supporting similar level of growth as nitrate control, were: P-3, 4 and 8 in pea and vetch group; G-23, 27, and, D-216 in soybean group.