• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.434-440
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• 2013

This study was conducted to screen the characteristics and alginate-degrading activity of marine bacterium isolated from brown seaweed (Sargassum thunbergii). The results of 16S ribosomal RNA sequence analysis the strain the genus Vibrio and the strain was subsequently named Vibrio sp. PKA 1003. The optimum culture conditions for the growth of Vibrio sp. PKA 1003 were at pH 7, 3% NaCl, $25^{\circ}C$, and 6% alginic acid, with a 48-hour incubation time. A crude enzyme preparation from Vibrio sp. PKA 1003, showed its highest levels of alginate-degradation activity when cultured at pH 9, $30^{\circ}C$, and 6% alginic acid, with a 63-hour incubation time. Thin layer chromatography analyses confirmed that the crude enzyme released monomers or oligomers from sodium alginate, and results from trypsin treatment showed that the alginate degrading activity depends on this enzyme produced by Vibrio sp. PKA 1003. These results suggest that Vibrio sp. PKA 1003 and its alginate-degrading crude enzyme is useful for the production of alginate oligosaccharides.

• Research in Plant Disease
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• v.21 no.4
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• pp.280-289
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• 2015

Maize (Zea mays L.) is an economically important crop in worldwide. While the consumption of the maize is steadily increasing, the yield is decreasing due to continuous mono-cultivation and infection of soil-borne fungal pathogens such as Fusarium species. Recently, stalk rot disease in maize, caused by F. subglutinans and F. temperatum has been reported in Korea. In this study, we isolated bacterial isolates in rhizosphere soil of maize and subsequently tested for antagonistic activities against F. subglutinans and F. temperatum. A total of 1,357 bacterial strains were isolated from rhizosphere. Among them three bacterial isolates (GC02, GC07, GC08) were selected, based on antagonistic effects against Fusarium species. The isolates GC02 and GC07 were most efficient in inhibiting the mycelium growth of the pathogens. The three isolates GC02, GC07 and GC08 were identified as Bacillus methylotrophicus, B. amyloliquefaciens and B. thuringiensis using 16S rRNA sequence analysis, respectively. GC02 and GC07 bacterial suspensions were able to suppress over 80% conidial germination of the pathogens. GC02, GC07 and GC08 were capable of producing large quantities of protease enzymes, whereas the isolates GC07 and GC08 produced cellulase enzymes. The isolates GC02 and GC07 were more efficient in phosphate solubilization and siderophore production than GC08. Analysis of disease suppression revealed that GC07 was most effective in suppressing the disease development of stalk rot. It was also found that B. methylotrophicus GC02 and B. amyloliquefaciens GC07 have an ability to inhibit the growth of other plant pathogenic fungi. This study indicated B. methylotrophicus GC02 and B. amyloliquefaciens GC07 has potential for being used for the development of a biological control agent.

• Clinical and Experimental Pediatrics
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• v.49 no.4
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• pp.401-409
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• 2006

Purpose : Human metapneumovirus(hMPV) is a respiratory viral pathogen that causes a wide spectrum of illnesses, ranging from asymptomatic infection to severe bronchiolitis. The virus has been identified world widely, but so far it has not been published in Korea. Methods : We obtained clinical samples by nasopharyngeal aspiration from 218 children hospitalized due to acute lower respiratory tract infections at Soonchunhyang University Hospital in Cheonan from October, 2004 to April, 2005. We designed specific primers from conserved region of fusion glycoprotein of hMPV. Total RNA was extracted and RT-PCR was performed, and single specific 423 bp product was obtained. The PCR product was confirmed to be fusion glycoprotein RNA by sequencing. Results : We detected hMPV in 15(6.9 percent) of the 218 hospitalized children. The infected children comprised nine boys and six girls; their mean age was 2.8 years(5 mo-12 yrs) and they were diagnosed with pneumonia(60 percent), bronchiolitis(33.3 percent), croup(6.6 percent). The number of cases of detected hMPV in Korea increased dramatically during the period from March to May 2005. Conclusion : hMPV is circulating in Korean children and is associated with respiratory tract infection. Additional studies are required to define the epidemiology and the extent of diseases in the general population caused by hMPV.

• Research in Plant Disease
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• v.22 no.4
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• pp.227-235
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• 2016

Plant disease caused by root-knot nematode is a major problem in crop production. Using of chemical pesticides, one of the most efficient methods to control nematodes, have raised issues in toxicity to humans and animals and environmental pollution. In this study, to select actinomycete strains that have potential to serve as a microbial agent for control of nematodes, we investigated nematicidal activity of culture broth from 670 Streptomyces isolates. A culture filtrate of KRA15-528 isolate that was identified as S. flavogriseus on the basis of 16S rRNA sequence analysis, showed strong nematicidal activity against second stage of juveniles of Meloidogyne incognita and inhibited egg hatching; exposure to 10% of culture filtrate resulted in 71% juvenile mortality at 48 hours afters treatment and suppressed egg hatching by 54% at 9 days after treatment. When the KRA15-528 culture filtrate was partitioned with ethyl acetate and butanol, ethyl acetate layer exclusively showed strong activity; 91%, 53%, 30% of mortality at 1,000, 500, $250{\mu}g/ml$, respectively. Additionally, the culture filtrate suppressed gall formation on cucumber plant by M. incognita with no phytotoxicity. These results suggest that S. flavogriseus KRA15-528 has potential to serve as a microbial nematicide for the control of root-knot nematode disease.

• Journal of fish pathology
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• v.30 no.2
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• pp.89-96
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• 2017

The majority of freshwater ornamental fish are imported and distributed domestically, causing high risk of exposure to exotic pathogens and drug resistant bacteria in Korea. Aeromonas hydrophila is known as a common species of fresh water bacteria and opportunistic fish pathogen, as well as a species causing zoonotic infection. In this study, we isolated motile aeromonads from various imported freshwater ornamental fish and studied the characters of the isolates. Imported freshwater ornamental fish were purchased on day 1 after the fish were deposited in the aquarium. Bacteria were isolated from the liver, kidney and spleen of fish using 0.5% NaCl containing tryptic soy agar medium. Bacteria were grouped on the basis of their morphological characteristics. The colonies with clear zone on starch-ampicillin agar (SA agar) were tentatively identified as Aeromonas spp. Two hundred and twenty-six strains, about 70% of total isolates were assumed to be Aeromonas spp. Nine isolates were further identified based on the result of the API 20E test and PCR using primers specific for A. hydrophila 16S rRNA gene. The isolates were identified as A. hydrophila and the API 20E test showed differences in trisodium citrate, D-sucrose, D-melibiose, amygdalin and L-arabinose availability between the nine isolates and standard A. hydrophila. The susceptibilities of the isolated bacteria to 10 antibacterial agents were confirmed by the disk diffusion method. Isolated strains were found to be resistant to amoxicillin and ampicillin and sensitive to florfenicol. However, 7 isolates showed multiple drug resistances to erythromycin, oxytetracycline, nalidixic acid etc. Pathogenicity of the isolates was determined by the artificial challenge test on goldfish (Carassius auratus). Three isolates caused 60 ~ 80% mortality in goldfish within 5 days after the initiation of challenge. These results indicate that multiple drug resistant, highly pathogenic and exotic A. hydrophila can spread to domestic aquarium and the preventive treatment of fish before sale is necessary.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.201-209
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• 2014

This study was carried out in order to develop a biological control of anthracnose of red pepper caused by fungal pathogens. In particular, this study focuses on the Colletotrichum species, which includes important fungal pathogens causing a great deal of damage to red pepper. Antagonistic bacteria were isolated from the soil of pepper fields, which were then tested for biocontrol activity against the Colletotrichum gloeosporioides anthracnose pathogen of pepper. Based on the 16S rRNA sequence analysis, the isolated bacterial strain CS-52 was identical to Bacillus sp. The culture broth of Bacillus sp. CS-52 had antifungal activity toward the hyphae and spores of C. gloeosporioides. Moreover, the substances with antifungal activity were optimized when Bacillus sp. CS-52 was grown aerobically in a medium composed of 0.5% glucose, 0.7% $K_2HPO_4$, 0.2% $KH_2PO_4$, 0.3% $NH_4NO_3$, 0.01% $MnSO_4{\cdot}7H_2O$, and 0.15% yeast extract at $30^{\circ}C$. The inhibition of spore formation resulting from cellulase, siderophores, and indole-3-acetic acid (IAA), were produced at 24 h, 48 h, and 72 h, respectively. Bacillus sp. CS-52 also exhibited its potent fungicidal activity against anthracnose in an in vivo test, at a level of 70% when compared to chemical fungicides. These results identified substances with antifungal activity produced by Bacillus sp. CS-52 for the biological control of major plant pathogens in red pepper. Further studies will investigate the synergistic effect promoting better growth and antifungal activity by the formulation of substances with antifungal activity.

• Clinical and Experimental Pediatrics
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• v.48 no.2
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• pp.197-203
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• 2005

Purpose : Changes in metalloproteinases(MMP) activity have been demonstrated in several disease states, including rheumatoid arthritis and tumor metastasis. More importantly, increased myocardial MMP activity has been reported to occur in both clinical and experimental forms of dilated cardiomyopathy. There was no report about MMP in adriamycin(ADR)-induced cardiomyopathy. The purpose of this study was to investigate gene expression of MMP and tissue inhibitor of metalloproteinases(TIMP) in ADR-induced cardiomyopathy and clarify the relationship between MMP and cytokines. Methods : Male Sprague-Dawley rats were divided into two groups. The first group was control. The second group was given intraperitoneal injections of ADR(5 mg/kg) twice a week over two weeks. Serum concentrations of MMP, TIMP, interleukin(IL)-6 and tumor necrosis factor(TNF)-${\alpha}$ were measured. RNA extraction was performed from frozen rat hearts. Reverse transcription polymerase chain reaction(RT-PCR) was employed. cDNA Microarray analysis was performed by using a set of 5,184 sequence-verified rat cDNA clones. Results : Serum MMP and TIMP levels were not significantly different between the two groups. IL-6 was $36.8{\pm}2.8pg/mL$ and TNF-${\alpha}$ $2.2{\pm}2.7pg/mL$ in the ADR group. They were significantly higher than in the control group. Serum MMP correlated significantly with TNF-${\alpha}$(r=0.41, P<0.05). There was no gene expression of MMP, IL-6 or TNF-${\alpha}$ in the hearts of both groups. Gene expression of TIMP was significantly depressed in the hearts of the ADR group. Conclusion : These results suggested a potential role for TNF-${\alpha}$ in the regulation of extracellular matrix remodeling in ADR induced cardiomyopathy. Rapid screening of multiple decreased gene expression by DNA chip may be a useful diagnostic test to detect early cardiac injury before developing ADR induced cardiomyopathy.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.319-326
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• 2016

An antimicrobial bacterium to pathogenic microorganisms, strain $W5-1^T$ was isolated from Korean fermented-food Kimchi. The isolate was Gram-staining-variable, strictly aerobic, rod-shaped, endospore-forming, and motile with peritrichous flagella. It grew at $15-40^{\circ}C$, at pH 6.0-10.0, and in the presence of 0-4% NaCl. Strain $W5-1^T$ could hydrolyze esculin and xylan, and assimilate $\small{D}$-mannose, but not $\small{D}$-mannitol. Strain $W5-1^T$ showed antimicrobial activity against Listeria monocytogens, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella typhi. The G+C content of the DNA of strains $W5-1^T$ was 52.6 mol%. The predominant respiratory quinone was menaquinone-7 (MK-7) and the major cellular fatty acids were $C_{16:0}$, antieiso-$C_{15:0}$, $C_{18:0}$, and $C_{12:0}$. The strain contained meso-diaminopimelic acid in cell-wall peptidoglycan. On the basis of 16S rRNA gene sequence and phylogenetic analysis, the strain W5-1 was shown to belong to the family Paenibacillaceae and was most closely related to Paenibacillus pinihumi $S23^T$ (98.4% similarity) and Paenibacillus tarimensis $SA-7-6^T$ (96.4%). The DNA-DNA relatedness between the isolate and Paenibacillus pinihumi $S23^T$ was 8.5%, indicating that strain $W5-1^T$ represented a species in the genus Paenibacillus. On the basis of the evidence from this polyphasic study, it is proposed that strain $W5-1^T$ is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus kimchicus sp. nov. is proposed. The type strain is $W5-1^T$ (=KACC $15046^T$ = $LMG 25970^T$).

• Food Science and Preservation
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• v.22 no.3
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• pp.443-451
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• 2015

This study was carried out to investigate the quality characteristics and identification of acetic acid bacteria for black waxy rice vinegar. Eight (8) strains of acetic acid bacteria were isolated for the production of acetic acid and their acidities were then compared with commercial acetic acid bacteria. Among them, F1, H4, and two types of commercial bacteria (four best strains by vinegar zymogen) were selected. After analyzing the 16S rRNA sequence, both F1 and H4 strains were identified as acetobacter genus. Therefore, the F-1 and H-4 strains were named as Acetobacter sp. F-1 and Acetobacter sp. H-4, respectively. Acidity of black waxy rice vinegar during fermentation was steadily increased up to 16 days and the acidity was then constant. Total acidity content was higher when used FV-1 strain. In the results of Hunter's color value of black waxy vinegar, L value was at 75.01 to 80.11, while (+a) value was at 3.34 to 3.92, and (+b) value was at 12.84 to 18.09. The major organic acid of the black waxy vinegar was acetic acid. The total organic acid content was high when used H-4, F-1, C-2 and C-1 strains. The total free amino acid content of the black waxy vinegar by strain was the highest (351.43 mg%) of F-1 vinegar strain, and the lowest (247.74 mg%) of C-2 vinegar strain. A sensory evaluation of black waxy vinegar indicated that F-1 vinegar strain was better than the other samples in aspect of flavor, color, and overall preference.

• Journal of Life Science
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• v.25 no.6
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• pp.680-685
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• 2015

Previously, cellulase and xylanase producing microorganism, Bacillus subtilis NC1, was isolated from soil. Based on the 16S rRNA gene sequence and API 50 CHL test the strain was identified as Bacillus subtilis, and named as B. subtilis NC1. We cloned and sequenced the genes for cellulase and xylanase. Plus, the deduced amino acid sequences from the genes of cellulase and xylanase were determined and were also identified as glycosyl hydrolases family (GH) 5 and 30, respectively. In this study to optimize the medium parameters for cellulase production by B. subtilis NC1 the RSM (response surface methodology) based on CCD (central composite design) model was performed. Three factors, tryptone, yeast extract, and NaCl, for N or C source were investigated. The cellulase activity was measured with a carboxylmethyl cellulose (CMC) plate and the 3,5-dinitrosalicylic acid (DNS) methods. The coefficient of determination (R²) for the model was 0.960, and the probability value (p=0.0001) of the regression model was highly significant. Based on the RSM, the optimum conditions for cellulase production by B. subtilis NC1 were predicted to be tryptone of 2.5%, yeast extract of 0.5%, and NaCl of 1.0%. Through the model verification, cellulase activity of Bacillus subtilis NC1 increased from 0.5 to 0.62 U/ml (24%) compared to the original medium.