• Research in Plant Disease
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• v.18 no.2
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• pp.117-122
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• 2012

In 2006, the effect of soil pH adjustment on control of common scab of potato caused by Streptomyces spp. was evaluated in the field. Soil with an original pH 5.7 was treated with sulfur of 42 kg/10a and calcium hydroxide of 81.6 kg/10a and 184.5 kg/10a to adjust pH 5.0, 6.0 and 6.5, respectively. Additionally, the effect of gypsum (522 kg/10a) on soil pH and disease severity was examined. The soil pH of sulfur treatment plot was continuously declined from 5.13 at tuber initiation time to 5.01 at harvest. The disease severity of sulfur treatment plot was relatively low (22.8%) and the marketable yield of that was high (90.5%). By contrast, the soil pHs treated with calcium hydroxide (81.6 kg/10a and 184.5 kg/10a) were increased (pH 6.06 and 6.49, respectively) at harvest. In addition, calcium hydroxide treatment plots showed higher disease severities (51.0% and 61.1%), and lower marketable yields (55.7% and 37.0%). Meanwhile, the soil pH of gypsum treatment plot was not changed until harvest, and the disease severity and the marketable yield were not significantly different from those of control. The effect of crop rotation was also evaluated with four crops such as welsh onion, soybean, corn and Chinese cabbage. These crops were planted in the infested field from 2005 to 2007, and potatoes were planted in the same field in 2008. The disease severities of potatoes produced after rotations with welsh onion, soybean, corn and Chinese cabbage for 3 years were 13.1%, 16.7%, 28.9% and 30.2%, respectively. However, the disease severity of 73.1% was shown in continuous cropping of potato for 3 years. In addition, similar effects were exhibited in the marketable yield. These results demonstrate that the adjustment of soil pH and crop rotation might be very useful tools to control common scab of potato.

• Food Science of Animal Resources
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• v.30 no.3
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• pp.504-511
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• 2010

This study was undertaken to investigate the effects of feeding complex probiotics (Lactobacillus casei, Bacillus subtilis, Saccharomyces cerevisiae, Aspergillus oryzae, Streptomyces griseus, $1.5{\times}10^{10}$ CFU/kg) and antibiotics (oxytetracycline (OTC), 110 ppm) on growth performance and meat quality characteristics of broiler chicks. In the experiment 1, 0.3% complex probiotics feeding level was chosen to be proper addition level due to better average daily gain (ADG), feed conversion (FC) and dressing percent (DP) results among 3 levels (0.1, 0.3 or 0.5%). In the experiment 2, 5 treatments (T1, no probiotics + no antibiotics; T2, probiotics 0.3% + no antibiotics; T3, probiotics 0.3% + antibiotics 50%; T4, probiotics 0.3% + antibiotics 100%; T5, no probiotics + antibiotics 100%) were investigated. In the growth performance of broilers, T5 (antibiotics 100% only) showed the highest (p<0.05) ADG and FC values while T1 (control) showed the worst growth performance. However, T3 (probiotics 0.3% + antibiotics 50%) showed higher ADG (p<0.05), FC (p<0.05) and DP (p>0.05) values compared to control. In the breast and leg meat quality, T3 showed similar pH, proximate composition, cooking loss and meat color values except shear force value compared to T5. Addition of 0.3% probiotics with 50% antibiotics (T3) tended to lower the blood cholesterol levels of broiler chicks and Escherichia coli or Salmonella counts in cecum microflora of broiler chicks compared to T5. In the residual antibiotics analysis, T3 contained 0.04 ppm of residual antibiotics in the breast meat while T4 or T5 contained 0.1 ppm of residual antibiotics and addition of 0.3% probiotics with 50% antibiotics in broiler diets could lower the residual antibiotics level to 40% in the meat. As a result, 0.3% probiotics addition with 50% antibiotics in the broiler diets could be recommended for the production of high quality broiler meat.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.4 s.54
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• pp.349-357
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• 2005

New antioxidative substances for cosmeceuticals were screened from natural resources such as microbial metabolites, mushrooms, and medicinal plants. Four antioxidants were isolated from the fungal metabolite of Eupenicillium shearii and their structures were determined to be new phenolic compounds. The compounds were designated as melanocins A, B, C, and D. Melanocins $A{\sim}D$ exhibited free radical scavenging activity on DPPH and superoxide with $EC_{50}$ values of $21{\sim}94\;and\;7{\sim}84{\mu}M$, respectively, which were stronger activity than those of ${\alpha}-tocopherol$ and BHA. Melanocin A showed anti-wrinkle effects on the UV-irrated hairless mouse skin. A novel hispidin antioxidative compound designated as inoscavin A was isolated from the fruiting body of the mushroom, Inonotus xeranticus. Inoscavin A scavenged superoxide radical with $EC_{50}$ values of $0.03{\mu}g/mL$, and inhibited rat liver microsomal lipid peroxidation with $EC_{50}$ values of $0.3{\mu}g/mL$. Benzastatins $A{\sim}G$, the novel antioxidants isolated from the culture of Streptomyces nitrosporeus showed potent lipid peroxidation inhibitory activity with $EC_{50}$ values of $3{\sim}30{\mu}M$. A cyclopentene compound with strong hypopigmentary effect was isolated from the fungal metabolite of Penicillium sp. and identifed as terrein. Terrein significantly reduced melanin levels in a melanomacyte cell line, Mel-Ab. It showed 10 times stronger activity than kojic acid, but exhibited no cytotoxic effect even in $100{\mu}M$. It was suggested that terrein reduced melanin synthesis by reducing tyrosinase production by MITF down-regulation.

• Journal of Life Science
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• v.28 no.12
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• pp.1416-1423
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• 2018

With strong biotin binding affinity ($K_D=10^{-14}M$), the tetrameric feature of streptavidin could be used to increase the antigen binding activity of a camel heavy chain (VHH) antibody through their fusion, here stained with biotinylated horseradish peroxidase and subsequent immunoassays ELISA and Western blot analysis. For this application, we cloned the streptavidin gene amplified from the Streptomyces avidinii chromosome by PCR, and this was fused to the gene of the 8B9 VHH antibody which is specific to green fluorescent protein (GFP) antigens. To express a soluble fusion protein in Escherichia coli, we used the pUC119 plasmid-based expression system which uses the lacZ promoter for induction by IPTG, the pelB leader sequence at the N-terminus for secretion into the periplasmic space, and six polyhistidine tags at the C-terminus for purification of the expressed proteins using an $Ni^+$-NTA-agarose column. Although streptavidin is toxic to E. coli because of its strong biotin binding property, this soluble fusion protein was expressed successfully. In SDS-PAGE, the size of the purified fusion protein was 122.4 kDa in its native condition and 30.6 kDa once denatured by boiling, suggesting the tetramerization of the monomeric subunit by non-covalent association through the streptavidin moiety fusing to the 8B9 VHH antibody. In addition, this fusion protein showed biotin binding activity similar to streptavidin as well as GFP antigen binding activity through both ELISA and Western blot analysis. In conclusion, the protein resulting from the fusion of an 8B9 VHH antibody with streptavidin was successfully expressed and purified as a soluble tetramer in E. coli; it showed both biotin and GFP antigen binding activity suggesting the possible production of a tetrameric and bifunctional VHH antibody.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.330-342
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• 2018

The Streptavidin and Biotin system has been studied most extensively as the high affinity non-covalent binding of Biotin to STR ($K_D=10^{-14}M$) and four Biotin binding sites in tetrameric Streptavidin makes this system useful for the production of multivalent antibody. For the application of this system, we cloned Streptavidin amplified from Streptomyces avidinii chromosome by PCR and fused to gene of hAY4 single-chain Fv antibody specific to death receptor 4 (DR4) which is a receptor for tumor necrosis factor ${\alpha}$ related apoptosis induced ligand. The hAY4 single-chain Fv antibody fused to Streptavidin expressed in Escherichia coli showed 43 kDa monomer in heated SDS-PAGE. However, this fusion protein shown in both non-heated SDS-PAGE and Size-exclusion chromatography exhibited 172 kDa as a tetramer suggesting that natural tetramerization of Streptavidin by non-covalent association induced hAY4 single-chain Fv tetramerization. This fusion protein retained a Biotin binding activity similar to natural Streptavidin as shown in Ouchterlony assay and ELISA. Death receptor 4 antigen binding activity of purified hAY4 single-chain Fv fused to Streptavidin was also confirmed by ELISA and Westernblot. In addition, surface plasmon resonance analysis showed 60-fold higher antigen binding affinity of the hAY4-STR than monomeric hAY4 ScFv due to tetramerization. In summary, hAY4 single-chain Fv fused to Streptavidin fusion protein was successfully expressed and purified as a soluble tetramer in E. coli and showed both Biotin and DR4 antigen binding activity suggesting possible production of bifunctional and tetrameric ScFv antibody.

• Journal of Marine Life Science
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• v.8 no.2
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• pp.136-149
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• 2023

Basic bioactivities (antioxidant, anti-inflammatory, antibacterial, anticancer, antiviral) were investigated from 370 strains of marine bacteria, fungi, and microalgae obtained from various marine environmental regions in Korea, and the activity results were obtained at the collection site, isolation source, and species level was compared. In the case of marine bacteria, strains belonging to the generally useful genera Streptomyces and Bacillus were observed to have particularly strong efficacy and useful resources were mainly isolated from marine sediments. In the case of marine fungi and microalgae, results showing strong species-specific activity were confirmed, and results showing efficacy-specific activity were also obtained. Based on these results, it is a research result that can facilitate priority access as a strategic material for industrial revitalization and the establishment of a strategy to secure resources based on usefulness when conducting research on chemicals that are selectively effective against specific diseases or when conducting resource-based research. In addition, we believe that by using these results as material for sale through the Marine BioBank (MBB), academia and industry can use them to help accelerate the revitalization of the marine bio industry.

• Korean Journal of Environmental Agriculture
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• v.32 no.3
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• pp.231-239
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• 2013

BACKGROUND: The disease resistant (OsCK1) rice was generated by inserting choline kinase (CK1) and phosphinothricin acetyltransferase (PAT) genes isolated from Oriza sativa and Streptomyces hygroscopicus into the genome of rice (Nakdongbyeo). With the potential problems of safety, the non-target organism evaluation is required as an essential element for the environmental risk assessment of genetically modified (GM) crops. In present study, we studied the effects on survival of Misgurnus anguillicaudatus and Cyprinus carpio, commonly used as a model organism in ecotoxicological studies. METHODS AND RESULTS: The M. anguillicaudatus and C. carpio were fed on disease resistant (OsCK1) rice and non-genetically modified (non-GM) rice (Nakdongbyeo) to 0, 10, 100, 1,000 and 5,000 mg/L, as treatment concentration respectively. The OsCK1 rice used for the test was confirmed to have the OsCK1/PAT gene expression by the PCR and ELISA analysis. Feeding test showed that no significant differences in cumulative immobility and abnormal response of M. anguillicaudatus and C. carpio fed on between OsCK1 rice and non-GM rice. The 96hr-$LC_{50}$ values showed no difference between OsCK1 rice (>5,000 mg/L) and non-GM rice (>5,000 mg/L). CONCLUSION(S): The results of this study suggested that there was no significant difference in toxicity for M. anguillicaudatus and C. carpio between OsCK1 rice and non-GM counterparts.

• Korean Journal of Organic Agriculture
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• v.24 no.4
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• pp.945-955
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• 2016

To date, chemical managements of plant bacterial diseases are complicated by limitations on use of antibiotics in agriculture, antibiotic resistance development, and limited efficacy of alternative control agents. In this study, thus, we performed screening of eco-friendly farming material (notice no. 2-4-064) containing tannic acid as new antibacterial-activity against 7 plant bacterial pathogens: Pectobacterium carotovorum subsp. carotovorum (Pcc), Ralstonia solanacearum (Rs), Acidovorax avenae subsp. citrulli (Aac), Xanthomonas cirti pv. citri (Xcc), Erwinia pyrifoliae (Ep), Clavibacter michiganensis subsp. michiganensis (Cmm), and Streptomyces scabies (Sc), Initial screening of antibacterial effects of eco-friendly farming material was performed using the paper disk diffusion method and co-cultivation in broth culture. Tannic acid based eco-friendly farming material showed inhibitory effect against Pcc, Rs, Aac, Xcc, Cmm, and Ss, whereas it did not show inhibition zone against Ep. However, when it tested by co-cultivation in broth culture, it showed strong inhibition effect against all pathogens that declined growth curve compared to bacterial pathogen only. Interestingly, when we observed morphological changes on those pathogens by SEM, cell morphologies of 7 pathogens were slightly changed that seem to be malfunction in their cell envelope.

• Microbiology and Biotechnology Letters
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• v.6 no.1
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• pp.41-46
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• 1978

Piscicidal substance produced by Streptomyces sp. isolated from soil was toxic against various kinds of fish. After extraction with CH$Cl_3$ from the culture medium, the substance was purified by avicel column chromatography. In order to test toxicity, various kinds of fish were subjected to the acqueous solution of 100 us of the substance per liter of water. Generally, the substance was toxic to most fish, but Macropodus chinenes and Misgurnus mizolepis are resistant to the substance than Gobius similis and Pseudorasbora parva. The substance was stable at pH range, 3.0 to 7.0, but labile at alkaline pH, and to heat as well. Succinic dehydrogenase on most of tissue cell of Cyprinus carpio was inhibited by this substance strongly, but spinal cord was not inhibited. By addition of Cu and Pb salts to the culture medium, piscicidal substance producibility was activated.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.402-410
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• 2015

The purpose of this study was to estimate the chitinolytic and antifungal activity of Actinomycetes sp.isolated from waste mushroom media. In five kinds of waste mushroom media, Sinyeong mushroom and Yangsongi were the order of the population density of actinomycetes. Totally 91 chitinolytic isolates of Actinomycetes sp. were obtained from waste mushroom media. The isolates were categorized into 3 groups based on chitinolytic activity and antagonisms against Phytophthora capsici, Rhizoctonia solani, Sclerotinia sclerotiorum, Collectotrichum gloeosporioides, and Cladosporium cucumerinum in vitro. CA-23 was selected as a representative isolate of a group showing strong chitinolytic and antagonistic activities to all of the plant pathogens, while AA-65 was selected as a representative isolate showing no chitinolytic activities but strong antagonistic activities to the pathogens. CA-23 and AA-65 were highly effective on control of Phytophthora blight of hot-pepper, powdery mildew and scab of cucumber in a greenhouse tests. Among the isolates tested, CA-23 showed highest control efficacy, while AA-65 not only effectively controlled the diseases but also consistently increased plant growth and yield. Although the isolates are similarly affected on suppression of plant pathogens, the isolates could be differ from each other in modes of action. Further studies on mechanisms and practical applications are being progressed.