• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.337-343
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• 2004

A bacterial strain concurrently producing extracellular chitosanase and chitinase was isolated from soil and identified as a member of the $\beta$-subgroup of Proteobacteria through its 16S rRNA analysis and some biochemical analyses. The newly discovered strain, named as KNU3, had 99% homology of its 16S rRNA sequence with chitinolytic $\beta$-Proteobacterium CTE108. Strain KNU3 produced 34 kDa of chitosanase in addition to two chitinases of 68 kDa and 30 kDa, respectively. The purified chitosanase protein (ChoK) showed activity toward soluble, colloidal, and glycol chitosan, but did not exhibit any activity toward colloidal chitin. The optimum pH and temperature of ChoK were 6.0 and $70^{\circ}C$, respectively. The chitosanase was stable in the pH 4.0 to 8.0 range at $70^{\circ}C$, while enzyme activity was relatively stable at below $45^{\circ}C$. MALDI-TOF MS and N-terminal amino acid sequence analyses indicated that ChoK protein is related to chitosanases from Matsuebacter sp. and Sphingobacterium multivorum. HPLC analysis of chitosan lysates revealed that glucosamine tetramers and hexamers were the major products of hydrolysis.

• Journal of Microbiology and Biotechnology
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• v.18 no.12
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• pp.1958-1965
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• 2008

A denitrifying polyphosphate-accumulating bacterium (YKP-9) was isolated from activated sludge of a 5-stage biological nutrient removal process with step feed system. This organism was a Gram-negative, coccus-shaped, facultative aerobic chemoorganotroph. It had a respiratory type of metabolism with oxygen, nitrate, and nitrite as terminal electron acceptors. The 16S rRNA gene sequence of strain YKP-9 was most similar to the 16S rRNA gene sequence of Paracoccus sp. OL18 (AY312056) (similarity level, 97%). Denitrifying polyphosphate accumulation by strain YKP-9 was examined under anaerobic-anoxic and anaerobic-oxic batch conditions. It was able to use external carbon sources for polyhydroxyalkanoates(PHA) synthesis and to release phosphate under anaerobic condition. It accumulated polyphosphate and grew a little on energy provided by external carbon sources under anoxic condition, but did neither accumulate polyphosphate nor grow in the absence of external carbon sources under anoxic condition. Cells with intracellular PHA cannot accumulate polyphosphate in the absence of external carbon sources under anoxic condition. Under oxic condition, it grew but could not accumulate polyphosphate with external carbon sources. Based on the results from this study, strain YKP-9 is a new-type denitrifying polyphosphate-accumulating bacterium that accumulates polyphosphate only under anoxic condition, with nitrate and nitrite as the electron acceptors in the presence of external carbon sources.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.26-35
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• 2020

BACKGROUND: Microbes that govern a unique biochemical process of oxidizing ammonia into dinitrogen gas, such as anaerobic ammonium oxidation (anammox) have been reported to play a pivotal role in agricultural soils and in oceanic environments. However, limited information for anammox bacterial abundance and distribution in the terrestrial habitats has been known. METHODS AND RESULTS: Phylogenetic and next-generation sequencing analyses of bacterial 16S rRNA gene were performed to examine potential anammox bacteria in paddy soils. Through clone libraries constructed by using the anammox bacteria-specific primers, some clones showed sequence similarities with Planctomycetes (87% to 99%) and anammox bacteria (94% to 95%). Microbial community analysis for the paddy soils by using Illumina Miseq sequencing of 16S rRNA gene at phylum level was dominated by unclassified Bacteria at 33.2 ± 7.6%, followed by Chloroflexi at 20.4 ± 2.0% and Acidobacteria at 17.0 ± 6.5%. Planctomycetes that anammox bacteria are belonged to was 1.5% (± 0.3) on average from the two paddy soils. CONCLUSION: We suggest evidence of anammox bacteria in the paddy soil. In addition to the relatively well-known microbial processes for nitrogen-cycle, anammox can be a potential contributor on the cycle in terrestrial environments such as paddy soils.

• Journal of Korean society of Dental Hygiene
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• v.2 no.2
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• pp.201-213
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• 2002

The closely related species Actinobacillus actinomycetemcomitans, Hemophilus aphrophilus and Hemophilus paraphrophilus are common findings in oral microbiota. The aims of this study were to compare the distribution of three species in healthy subjects and periodontitis patients using PCR for 16s rRNA gene. The DNA was extracted from the subgingival plaque and saliva in 122 subjects for restriction enzyme analysis with Hinf I and Hha I. In case of periodontally healthy person, A. actinomycetemcomitans was predominant than H. paraphrophilus in saliva sample, but H. paraphrophilus was predominant than A. actinomycetemcomitans in subgingival plaque sample. On the contrary, in case of periodontitis patients, H. paraphrophilus was predominant than A. actinomycetemcomitans in saliva sample, but A. actinomycetemcomitans was predominant than H. paraphrophilus in subgingival plaque sample. In addition, the fact was confirmed that the distribution of A. actinomycetemcomitns of women periodontitis patients was somewhat higher than men periodontitis patients in saliva and subgingival plaque samples. We convinced that the PCR method for 16s rRNA gene was important for screening and monitoring of periodontal disease.

• Journal of Microbiology and Biotechnology
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• v.22 no.5
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• pp.674-683
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• 2012

A new strain, SD12, was isolated from tannery waste polluted soil and identified as Pseudomonas aeruginosa on the basis of phenotypic traits and by comparison of 16S rRNA sequences. This bacterium exhibited broad-spectrum antagonistic activity against phytopathogenic fungi. The strain produced phosphatases, cellulases, proteases, pectinases, and HCN and also retained its ability to produce hydroxamate-type siderophore. A bioactive metabolite was isolated from P. aeruginosa SD12 and was characterized as 1-hydroxyphenazine ((1-OH-PHZ) by nuclear magnetic resonance (NMR) spectral analysis. The strain was used as a biocontrol agent against root rot and wilt disease of pyrethrum caused by Rhizoctonia solani. The stain is also reported to increase the growth and biomass of Plantago ovata. The purified compound, 1-hydroxyphenazine, also showed broad-spectrum antagonistic activity towards a range of phytopathogenic fungi, which is the first report of its kind.

• Fisheries and Aquatic Sciences
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• v.15 no.1
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• pp.83-89
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• 2012

Flavobacterium johnsoniae was isolated from farmed rainbow trout Oncorhynchus mykiss in Korea, and its biochemical and molecular characterization was determined. Yellow-pigmented bacterial colonies were isolated from 18 of 64 fish samples (28.1%) on trypticase soy agar plates, and their biochemical profiles were characterized by API 20E and API 20NE test kits. F. johnsoniae was identified by biochemical phenotyping of factors including rapid gliding motility, Gram-negative condition, oxidase- and catalase-positive status, Congo red absorption, nitrate reduction, ${\beta}$-galactosidase production, acid production from glucose, and gelatin and casein hydrolysis. PCR and subsequent sequencing of 16S rRNA confirmed that the yellow-pigmented colonies were most similar to F. johnsoniae. The alignment analysis of 16S rRNA sequences also showed that all 18 rainbow trout isolates had highly similar homologies (97-99% identity). One isolate was selected and named FjRt09. This isolate showed 98% homology with previously reported F. johnsoniae isolates, and in phylogenetic analysis was more closely grouped with F. johnsoniae than with F. psychrophilum, F. columnare, or F. branchiophilum. This is the first report on the occurrence and biochemical characterization of F. johnsoniae isolated from rainbow trout in Korea.

• Korean Journal of Veterinary Service
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• v.31 no.2
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• pp.187-193
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• 2008

Ehrlichia chaffeensis infects human and animals, and causes human monocytotropic ehrlichiosis (HME). It is emerging as a tick-borne zoonosis of concern. Although deer are important natural reservoir hosts of E chaffeensis, few surveys of deer in Korea for E chaffeensis have been conducted. Therefore, we conducted this study to confirm the occurrence of E chaffeensis in deer. To accomplish this study, we collected blood from total 27 deer and then polymerase chain reaction (PCR) and 16S rRNA sequence analyse to evaluate the samples for the presence of E chaffeensis. The results of this study indicated that 9 (33%) of the deer were infected with E chaffeensis. This is the first study to demonstrate that deer in Korea are infected with E chaffeensis, which indicates that they can act as a natural reservoir host for E chaffeensis.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.3
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• pp.199-204
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• 2003

Among 59 Korean isolated, 20 were confirmed as members of the genus Bifidobaferium species based on gram staining, microscopic examination of cell morphology and the TLC method, The oxygen tolerance and antioxidative activities of these 20 Bifidobacterium strains and 5 standard Bifidobaferium strains were tested. All the strains demonstrated antioxidative activities as regards inhibiting linoleic acid peroxidation. The antioxidative activities of isolated and standard strains were found to range from 10.7-46.4% and from 10.7-22.2%, respectively. In addition, all tested strains exhibited a Scavenging ability on DPPH free radicals, range from 15-41% for the isolated strains and 8.3-22% for the standard strain. Accordingly. the isolated Bifidobarterium strains demonstrated higher antioxidative artivities than the 5 standa rd Bifidobarterium strains. On the base of grades for each test, HJL 7511 was identified 35 the best strain, followed by HJL 7501. 2 strains were identified with Polymerase Chain Reaction (PCR) assay using group-specific primers designed from the nucleotide Sequences of the 16S rRNA and internal transcribed spacer (ITS) regions of the Bifidobacteria. Based on the Sequencing results, HJL 7511 and HJL 7501 were identified as Bifidobacterium infantis.

• The Korean Journal of Mycology
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• v.37 no.2
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• pp.181-188
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• 2009

A Gram-positive, rod-shaped bacteria named DY5 was isolated from a peat sample collected from Daeam mountain in Korea. The culture filtrate of the bacterial isolate DY5 showed a broad spectrum of antifungal activity on various crop pathogenic fungi such as Trichoderma koningii, Fusarium oxysporum, Colletotrichum gloeosporioides, Sclerotinia sclerotiorum, Rhizoctonia solani AG-1(IA) For the identification of the DY5, morphological, biochemical, API 50 CHB test, analysis of fatty acid and molecular phylogenetic approaches were performed. The DY5 was found to be a member of the genus Paenibacillus on the basis of morphological and biochemical analysis. The 16S rRNA of DY5 showed high similarity(98%) with Paenibacillus polymyxa. On the basis of these results, the DY5 was identified as Paenibacillus polymyxa. Antifungal substance of the DY5 would be mild alkaline proteine molecule. The DY5 seems to have a great potential to be a biocontrol agent against various crop pathogens.

• Journal of Life Science
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• v.22 no.12
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• pp.1724-1728
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• 2012

A marine bacterial strain that degraded fucoidan from Ecklonia cava was isolated from seawater. The crude fucoidanase of this strain efficiently degraded fucoidan at pH 8 and $50^{\circ}C$. The crude enzyme hydrolyzed 7.1% (w/w) fucoidan within 24 hrs from an 1% (w/v) fucoidan solution and produced oligosaccharides by endo-type hydrolysis as the reaction products. The results of 16S rRNA gene sequence analysis and biochemical tests permitted a tentative identification of strain SB 1493 as a Pseudoalteromonas species.