• 한국균학회지
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• 제23권2호통권73호
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• pp.190-195
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• 1995

고추탄저병(Colletotrichum gloeosporioides)에 대한 생물학적방제 능력을 가지는 엽권미생물을 선발하기 위하여 38과 87종의 약용식물로부터 243균주의 세균과 51균주의 사상균 그리고 30균주의 효모를 분리하여 이들에 대하여 항진균활성검정을 in vitro 및 in vivo에서 실시한 결과는 다음과 같다. 분리된 엽권미생물 중에서 PDA 배지 대치배양에서 10 mm 이상의 생육저지대를 형성하는 4개의 엽권미생물이 선발되었다. 선발된 4개의 세균균주 KB6, KB12, KB13 및 KB14의 PDB 배양여액 중에서 KB12 균주가 균사생장 억제율이 가장 높았다. 액체배양여액 처리에서 푸른 고추보다 붉은 고추에서 방제효과가 컸다. Bacterial cell 처리에서는 푸른 고추나 붉은 고추에서도 높은 방제효과가 있었다. 선발된 4개의 세균균주들은 모두 Bacillus subtilis로 동정되었다.

• 한국임상수의학회지
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• 제25권5호
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• pp.346-354
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• 2008

The combined effects of EDTA-Tris and eighteen antimicrobial agents have been evaluated in eight clinically isolated methicillin-resistant bacteria (Staphylococcus aureus, Escherichia coli, Streptococcus uberis and Streptococcus agalactiae) from bovine mastitis. The antimicrobial activity was evaluated by measuring the minimal bactericidal concentration (MBC) for the antibiotics alone or in combination with EDTA-Tris in Mueller-Hilton broth and milk. Combined use of EDTA-Tris and antibiotics potentiated or antagonized activity of antibiotics against mastitic pathogens. Milk increased the antibiotic potency of erythromycin and spiramycin on S. aureus. Culture in milk changed patterns of EDTA-Tris combinational effects compared with that in standard Mueller-Hilton broth. Combined with EDTA-Tris in milk, synergic effects were observed in colistin, dihydrostreptomycin, kanamycin, erythromycin, gentamycin, oxytetracycline, streptomycin to E. coli, Str. uberis, and Str. agalactiae. However, significant antagonistic effects of milk on antibiotic susceptibility in combination with EDTA-Tris were noted in neomycin, streptomycin, penicillin, roxithromycin, and amoxicillin. This study indicates that combination therapy of EDTA-Tris with antibiotics in bovine mastitis should be used with caution because of the possible antagonistic effects of antibiotic combination with EDTA-Tris on mastitic pathogens. In addition, antibiotic susceptibility test in combination with EDTA-Tris in milk culture condition can be benefit in search of effective treatment regimen for some antibiotic-resistant bacteria of mastitis.

• Applied Biological Chemistry
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• 제38권5호
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• pp.371-375
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• 1995

식물 병원성 사상균 F. oxysporum과 R. solani에 대하여 우수한 길항력을 갖는 Pseudomonas (P.) fluorescens를 작물 근권으로 부터 분리하여 생리, 생화학적 특성을 조사하였다. 이들 분리 근권길항 미생물중 한 균주인 Ps70과 plasmid pSV2-neo를 이용하여 electroporation에 의한 길항 미생물 P. fluorescens의 transformation 가능성과 최적 조건을 조사하였다. 그 결과 10% glycerol을 P. fluorescens buffer로 사용하여 2.5kV의 voltage, $200{\Omega}$의 resistance에서 최적의 electrotransformation 효과를 보였다. 또한, 이균주에 크기가 서로 다른 plasmid를 electroporation하여 transformation 효과를 비교한 결과 voltage, electroporation buffer의 조성, 그리고 resistance (time constant)가 transformation의 효과를 증진하는데 주요한 역할을 하는것으로 나타났으며, 또 다른 P. fluorescens 균주에 같은 실험을 반복한 결과 유사한 electrotransformation 효과를 보였다.

• Journal of Ginseng Research
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• 제42권3호
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• pp.304-311
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• 2018

Background: Ginseng black spot disease resulting from Alternaria panax Whuetz is a common soil-borne disease, with an annual incidence rate higher than 20-30%. In this study, the bacterial strains with good antagonistic effect against A. panax are screened. Methods: A total of 285 bacterial strains isolated from ginseng rhizosphere soils were screened using the Kirby-Bauer disk diffusion method and the Oxford cup plate assay. We analyzed the antifungal spectrum of SZ-22 by confronting incubation. To evaluate the efficacy of biocontrol against ginseng black spot and for growth promotion by SZ-22, we performed pot experiments in a plastic greenhouse. Taxonomic position of SZ-22 was identified using morphology, physiological, and biochemical characteristics, 16S ribosomal DNA, and gyrB sequences. Results: SZ-22 (which was identified as Brevundimonas terrae) showed the strongest inhibition rate against A. panax, which showed 83.70% inhibition, and it also provided broad-spectrum antifungal effects. The inhibition efficacies of the SZ-22 bacterial suspension against ginseng black spot reached 82.47% inhibition, which is significantly higher than that of the 25% suspension concentrate azoxystrobin fungicide treatment (p < 0.05). Moreover, the SZ-22 bacterial suspension also caused ginseng plant growth promotion as well as root enhancement. Conclusion: Although the results of the outdoor pot-culture method were influenced by the pathogen inoculum density, the cropping history of the field site, and the weather conditions, B. terrae SZ-22 controlled ginseng black spot and promoted ginseng growth successfully. This study provides resource for the biocontrol of ginseng black spot.

• The Plant Pathology Journal
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• 제36권3호
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• pp.244-254
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• 2020

Gom-chwi (Ligularia fischeri) is severely infected with Phytophthora drechsleri, the causal organism of Phytophthora root rot, an economically important crop disease that needs management throughout the cultivation period. In the present study, Phytophthora root rot was controlled by using bacterial isolates from rhizosphere soils collected from various plants and screened for antagonistic activity against P. drechsleri. A total of 172 bacterial strains were isolated, of which, 49 strains showed antagonistic activities by dual culture assay. In the seedling assay, six out of the 49 strains showed a predominant effect on suppressing P. drechsleri. Among the six strains, the ObRS-5 strain showed remarkable against P. drechsleri when treated with seed dipping or soil drenching. The ObRS-5 strain was identified as Enterobacter asburiae based on 16S ribosomal RNA gene sequences analysis. The bacterial cells of E. asburiae ObRS-5 significantly suppressed sporangium formation and zoospore germination in P. drechsleri by 87.4% and 66.7%, respectively. In addition, culture filtrate of E. asburiae ObRS-5 also significantly inhibited sporangium formation and zoospore germination by 97.0% and 67.6%, respectively. Soil drenched bacterial cells, filtrate, and culture solution of E. asburiae ObRS-5 effectively suppressed Phytophthora root rot by 63.2%, 57.9%, and 81.1%, respectively. Thus, E. asburiae ObRS-5 could be used as a potential agent for the biological control of Phytophthora root rot infecting gom-chwi.

• Preventive Nutrition and Food Science
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• 제2권2호
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• pp.109-120
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• 1997

In order to elucidate roles of lactic acid bacteria(LAB) for the antibiosis occurring in th fermenting environment of Kimchi, 2.052 strains of LAB were isolated from Kimchi. Fifty tow strains which showed antagonistic effect against 4 indicator strains were finally selected and investigated. Based upon responses to protease treatment, antibiosis of the 52 strains of LAB were classified into 3 types. Type A antibiosis resulted from action of antibiotic-like substances which were not affected by protease treatment and which had broad action spectra against even natural inhabitants of Kimchi. Type B antibiosis was due to bacteriocin-like substances which were very sensitive to treatment of protease and more effective against foreign bacteria than original inhabitant microflora. Type C antibiosis was owing to proteinaceous compounds which were activated or induced by the presence of protease and then exerted antibacterial activities. Therefore, lactic acid bacteria appeared to contribute to antibiosis of Kimchi by the concerted action of these three different types of antibacterial compounds. As one of model system for type B bacteriocin, the antagonistic compound produced by LAB31-9 as well as th producer strain itself was further charaacterized. Strain LAB31-9 was identified as L. casei. Bacteriocin produced by LAB31-9 was proteinaceous and stable over wide range of pH and to various solvents, but very labile to heat treatment. Its mode of action was bactericidal. Based upon these data, bacteriocin produced by LAB31-9 was named as 'caseicin K319'. Genetic determinant for the bacteriocin production of LAB31-9 was located in the chromosome.

• The Journal of Advanced Prosthodontics
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• 제11권1호
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• pp.23-31
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• 2019

PURPOSE. To investigate and compare the surface roughness (SR), weight and height of monolithic zirconia (MZ), ceramometal (CM), lithium disilicate glass ceramic (LD), composite resin (CR), and their antagonistic human teeth enamel. MATERIALS AND METHODS. 32 disc shaped specimens for the four test materials (n=8) and 32 premolars were prepared and randomly divided. SR, weight and height of the materials and the antagonist enamel were recorded before and after subjecting the specimens to 240,000 wear-cycles ($49N/0.8Hz/5^{\circ}C/50^{\circ}C$). SR, height, weight, and digital microscopic qualitative evaluation were measured. RESULTS. CM ($0.23+0.08{\mu}m$) and LD ($0.68+0.16{\mu}m$) exhibited the least and highest mean difference in the SR, respectively. ANOVA revealed significance (P=.001) between the materials for the SR. Paired T-Test showed significance (P<.05) for the pre- and post- SR for all the materials. For the antagonistic enamel, no significance (P=.987) was found between the groups. However, the pre- and post- SR values of all the enamel groups were significant (P<.05). Wear cycles had significant effect on enamel weight loss against all the materials (P<.05). CR and MZ showed the lowest and highest height loss of 0.14 mm and 0.46 mm, respectively. CONCLUSION. MZ and CM are more resistant to SR against the enamel than LD and CR. Enamel worn against test materials showed similar SR. Significant variations in SR values for the tested materials (MZ, LD, CM, and CR) against the enamel were found. Wear simulation significantly affected the enamel weight loss against all the materials, and enamel antagonist against MZ and CM showed more height loss.

• 한국버섯학회지
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• 제17권1호
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• pp.19-23
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• 2019

Pseudomonas agarici에 의해 발생하는 세균성회색무늬병은 양송이버섯 재배에서 문제가 되는 대표적인 병해이다. 본 연구에서는 세균성회색무늬병의 생물학적 방제법에 이용할 수 있는 길항미생물의 항균활성과 선발된 길항미생물에 대해 폿트 수준의 생물검정 실험을 실시하였다. 재배중인 양송이버섯 배지에서 세균성회색무늬병 병원균을 강하게 억제하는 길항세균 HC42를 선발하였으며, 생리 생화학적 실험과 유전적 실험결과 HC42균주는 B. safensis로 동정되었다. B. safensis HC42를 양송이에 처리한 결과 66%의 방제효과를 보였다. 따라서 B. safensis HC42가 양송이버섯 세균성회색무늬병 방제를 위해 합성농약을 대체할 수 있는 친환경 방제제가 될 수 있을 것으로 생각된다.

• The Plant Pathology Journal
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• 제37권3호
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• pp.215-231
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• 2021

Brown leaf spot disease caused by Nigrospora guilinensis on Phellodendron chinense occurs in a large area in Dayi County, Chengdu City, Sichuan Province, China each year. This outbreak has severely reduced the production of Chinese medicinal plants P. chinense and caused substantial economic losses. The bacterial isolate JKB05 was isolated from the healthy leaves of P. chinense, exhibited antagonistic effects against N. guilinensis and was identified as Bacillus megaterium. The following fermentation medium and conditions improved the inhibitory effect of B. megaterium JKB05 on N. guilinensis: 2% glucose, 0.1% soybean powder, 0.1% KCl, and 0.05% MgSO₄; initial concentration 6 × 10⁶ cfu/ml, and a 42-h optimal fermentation time. A composite of 0.1% nano-SiO₂ JKB05 improved the thermal stability, acid-base stability and ultraviolet resistance by 16%, 12%, and 38.9%, respectively, and nano-SiO₂ was added to the fermentation process. The best formula for the wettable powder was 35% kaolin, 4% polyethylene glycol, 8% Tween, and 2% humic acid. The following quality test results for the wettable powder were obtained: wetting time 87.0 s, suspension rate 80.33%, frequency of microbial contamination 0.08%, pH 7.2, fineness 95.8%, drying loss 1.47%, and storage stability ≥83.5%. A pot experiment revealed that the ability of JKB05 to prevent fungal infections on P. chinense increased considerably and achieved levels of control as high as 94%. The use of nanomaterials significantly improved the ability of biocontrol bacteria to control this disease.

• 생약학회지
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• 제15권3호
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• pp.121-127
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• 1984

Attempts were to investigate the effects of 'Bojungikgi-tang' on the digestive system, blood pressure and diuresis. The results showed that relaxing action was shown on the isolated ileum in mice and that strong antagonistic actions were seen on $BaCl_2$, acetylcholine and histamine-induced contraction of the ileum in mice and guinea-pigs that the relaxing effect of the intestinal smooth muscle was recognized. Inhibitory effects on transport rate in the small intestine of mice and castor oil-induced catharsis in mice were noted. Inhibitory action on the secretion of gastric juice, pH ascending effect and decreasing effect of the free acidity and total acidity were recognized. Continuous hypotensive action was seen, but when the vagus nerve was cut, hypotensive action was remarkably decreased. The diuretic effect was also recognized.