• The Plant Pathology Journal
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• v.20 no.4
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• pp.271-276
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• 2004

To examine the control effect of damping-off on radish caused by Pythium spp., researchers used the isolates of a fungivorous nematode, Aphelenchus avenae, and antagonistic fungi, Trichoderma spp. These were used as biocontrol agents, either alone, or in combination. Growth rates of the A. avenae isolates and fungal damages by the nematodes varied depending on Trichoderma spp., which contained lower T. koningii and T. virens cultures than other Trichoderma cultures. Phythium spp. were damaged by all five Aphelenchus isolates, but the multiplication rate of nematode isolate Aa-3 was very poor. Antibiotic activity of T. virens and T. harzianum to Pythium spp. was stronger than that of T. koningii. Control efficacy against damping-off of radish was most enhanced under the treatment using the nematode-T. harzianum combination. On the contrary, the combinations of the nematodes and T. virens or T. koningii mostly did not increase or decreased their control effect vis-$\`{a}$-vis that of the nematodes or antagonistic fungi being used alone. The results suggest that the fungivorous nematodes may play a leading role in the disease control, and that the activity of the fungivorous nematodes may be activated by T. harzianum, but inhibited by T. koningii and T.virens.

• Culinary science and hospitality research
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• v.9 no.4
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• pp.113-122
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• 2003

This study was conducted to examine the antagonism of useful microbes against soybean sprout rotting pathogens and their effect on the growth of soybean sprouts. The antagonism against soybean sprout rotting pathogens and the effect on the growth of soybean sprouts were examined by using P. areofacience 14H-3, P. fluorescens R1-12 and B. cereus Yell, bacteria were shown to inhibit mycellial growth of Rhizotonia solani strongly. The results of this study are summarized as follows. P. areofacience 14H-3 and B. cereus Yell were highly antagonistic against Rizoctonia solani, while they were especially highly antagonistic against bacterial diseases. The effect of inhibiting the proliferation of soybean sprout rotting pathogens was also examined by adding the culture solution for antagonistic bacteria to the PDA. Both P. areofacience 14H-3 and P. fluorescens Rl-12 showed the inhibition rate of 78.8%, while B. cereus Yell did 52.9%. The fresh weight and length of soybean sprouts were measured after raising them with added antagonistic microbes and culture medium. Soybean sprouts treated with B. cereus Yell showed increased higher, compared with those not treated with it. Soybean sprouts were also raised in the culture solution with antagonistic bacteria to examine the growth of soybean sprouts. Soybean sprouts treated with the culture solution of 200 times showed better growth than those not treated with it. Analyze proximate composition in soybean sprout showed that moisture, ash, total sugar did not appear difference, but in case of crude protein B. cereus Yell(8.9%) increased about 2 times than control(3.6%), but occasion of crude fat and crude fiber were P. areofacience 14H-3, P. fluorescens Rl-12 increased about each 2 times than control. In occasion of vitamin, bacterial antagonist(9.4∼10.8mg%) was more higher than control(9.9mg%).

• Journal of Life Science
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• v.20 no.8
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• pp.1254-1260
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• 2010

Microorganisms near the plant rhizosphere usually inhabit the surface or the inside of the plant roots and have a direct effect on plant growth by secreting plant growth promoters or antagonistic materials which protect the root zone system from various pathogens. This study was carried out to identify and isolate the antagonistic materials after isolation of microorganisms showing high antagonistic activities, in hopes of contributing to the development of sustainable agriculture and the preservation of agricultural environments. A number of antagonistic bacteria were isolated from paddy soil. Among isolates, RRj 228 showed plant growth promotion and antagonistic activity. RRj 228 was identified as Pseudomonas sp. according to the results of physiological properties and genetic methods. On the basis of the results of anti-fungal spectrum against several pathogens by RRj 228, the antagonistic effect of the isolate against Botrytis cinerea, Pythium ultimum, Phytopthola capsici, and Rhizoctonia solani, especially against red-pepper anthracnose caused by Colletotrichum acutatum, was remarkable. The experiment evaluating the biological control effect by RRj 228 revealed that the $ED_{50}$ value by the RRj 228 culture against C. acutatum, R. solani and P. ultimum were 0.14 mg/ml, 0.16 mg/ml and 0.29 mg/ml, respectively. An antagonistic substance was isolated and purified by several chromatographies from the RRj 228 culture. The $^1H$ and $^{13}C$ assignment of the antagonistic substance was achieved from two-dimensional $^1H-^1H$ COSY, HMQC, and HMBC. Finally, the antagonistic substance was identified as Phenazine-1-carboxylic acid ($C_{13}H_8N_2O_2$, M.W.=224).

• Journal of Life Science
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• v.13 no.6
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• pp.843-848
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• 2003

Diarrllea and death of chicken have been brought about by fowl typhoid caused by Salmonella gallinarum, which causes a great loss of chicken farms. For the development of the probiotic which can control a fowl typhoid of S. gallinarum without any adverse effect of commercial existing antibiotics, we isolated antagonistic intestinal bacteria against S. gallinarum from a bowel of the chicken which was pastured in a chicken farm of Gumi, Kyoungbuk. An Y3 strain which had a strong antagonistic ability to S. gallinarum was selected as a candidate of chicken probiotic microorganism among isolated strains. It was identified as a Bacillus amyloliuefaciens by 98% similarity by the result of cultural, physiological, biochemical test and Biolog system$(Microlog^{TM} 4.0)$, and named as Bacillus amyloliquefaciens Y3. The strain showed the strongest antagonistic activity and a good growth at pH 5-9, $37^{\circ}C.$

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.1
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• pp.58-64
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• 1990

This study was conducted to investigate the interaction effect of a new plant growth regulator brassinolide and auxins using several bioassay methods such as rice lamina inclination test, oat coleoptile segment growth test and radish hypocotyl elongation test. For rice lamina inclination test, the antagonistic response showed at low concentration combinations of homobrassinolide and auxins (IAA and 2,4-D), while the combinations of high concentration responsed mostly synergistic or additive effects, IAA was generally higher than 2,4-D for combination effect with homobrassinolide. For oat coleoptile segment growth test, the synergistic effect showed at IAA concentrations less than 0.1ppm while additive response exhibited above 0.3ppm regardless of homobrassinolide concentrations. In radish hypocotyl elongation test, the interaction response varied with cotyledon. The sections removed cotyledon showed mostly antagonistic effects, except for combination of homobrassinolide with IAA 3ppm. Interaction responses were Quite different from bioassay methods, particularly using experimental materials: antagonistic responses were usually shown at the section that attached growing point while these for sections that removed growing point were responded synergistic or additive effect due to unstable endogenous hormones.

• Journal of Microbiology and Biotechnology
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• v.5 no.6
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• pp.341-345
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• 1995

Seventy four microorganisms, which have antagonistic activity against to Fusarium culmorum, were tested for their inhibitory effect on colony development of obligate biotroph Erysiphe graminis f. sp. hordei Marchal, the causal agent of powdery mildew on barley plants. Of these, 13 actinomycetes isolates were shown to reduce the colony development of mildew completely by application of their 10% cell-free culture filtrates on barley leaves. An Isolate, A252, was the most powerful antagonist and its antifungal activity was further assessed. The colony development of mildew was significantly reduced by application of the 1% cell-free culture filtrate of isolate A252. In comparison to the control, the protective and curative application of 10% cell-free culture filtrate from A252 showed 88.5% and 96.1% reduction of colony numbers respectively. By the protective application, 68.3% of the inhibition was observed after 9 days of treatment, thus showed prolonged inhibitory effect. In vitro test, complete inhibition of the mycelial growth of Microdochium nivale was achieved by the treatment of 1% A252 culture filtrate and 80.2% of inhibition was observed by the 0.1% treatment.

• Journal of Microbiology and Biotechnology
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• v.17 no.5
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• pp.858-864
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• 2007

This study investigated the antibacterial activities of sophoraflavanone G from Sophora flavescens in combination with two antimicrobial agents against oral bacteria. The combined effect of sophoraflavanone G and the antimicrobial agents was evaluated using the checkerboard method to obtain a fractional inhibitory concentration(FIC) index. The sophoraflavanone G+ampicillin(AM) combination was found to have a synergistic effect against S. mutans, S. sanguinis, S. sobrinus, S. gordonii, A. actinomycetemcomitans, F nucleatum, P. intermedia, and P. gingivalis, whereas the sophoraflavanone G+gentamicin(GM) combination had a synergistic effect against S. sanguinis, S. criceti, S. anginosus, A. actinomycetemcomitans, F nucleatum, P. intermedia, and P. gingivalis. Neither combination exhibited any antagonistic interactions(FIC index>4). In particular, the MICs/MBCs for all the bacteria were reduced to one-half$\sim$one-sixteenth as a result of the drug combinations. A synergistic interaction was also confirmed by time-kill studies for nine bacteria where the checkerboard suggested synergy. Thus, a strong bactericidal effect was exerted through the drug combinations, plus in vitro data suggested that sophoraflavanone G combined with other antibiotics may be microbiologically beneficial rather than antagonistic.

• Korean Journal of Environmental Agriculture
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• v.29 no.1
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• pp.86-91
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• 2010

This study was carried out to assess the antifungal potential of R. oligosporus and its ethyl acetate (EtOAc) extract against the fungal pathogens causing anthracnose disease in apple fruits using disc diffusion, antagonistic effect and morphological abnormalities in fungal mycelia. The percentage of inhibition of antifungal effect of the ethyl acetate extract (5 ${\mu}l$ $disc^{-1}$) of the R. oligosporus against C. acutatum KACC 40848, C. gloeosporioides KACC 40897, C. higginsianum KACC 40806, C. orbiculare KACC 40808, C. coccodes KACC 40008, C. musae KACC 40947, C. boninense KACC 40893, C. liliacearum KACC 40981, C. caudatum KACC 41028 and Colletotrichum sp. KACC 40811 was found to be 44.4, 35.5, 40, 31.1, 33.3, 37.7, 40, 51.1, 28.8 and 28.8%, respectively. Also the fungus R. oligosporus showed potential antagonistic effect of antifungal activity against the tested pathogens of Colletotrichum spp. Further, R. oligosporus had a potential detrimental effect on the morphology of the tested fungi of Colletotrichum spp. such as wrinkle abnormalities, abnormal cell formation, lysis of mycelium, empty cell formation, distorted cell formation and breakage of the mycelium. These findings strongly support the role of R. oligosporus to serve as a potential antifungal agent to control plant pathogenic fungi causing anthracnose disease in apple fruits.

• Korean Journal of Microbiology
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• v.11 no.4
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• pp.175-180
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• 1973

This study was attempted to see more clear relationships among the enterobacteria, especially between the intestinal normal flora and pathogenic bacteria. It has been known that some intestinal normal flora produce the bactrial metabolites that are harmful to other enteric bacteria. One of the metabolites is known as colicin, the protein fraction, which possesses certain degree of inhibitory effect against other bacterial growth fraction, whih possesses certain degree of inhibitory effect against other bacterial growth. As a preliminary study for a colicin purification, the antagonistic effect of E, coli to groups of Salmonella and Shigella has been studied by means of in vitro quantitative culture method. 1. E.coli showed definite inhibitory effects aganist both Salmonella and Shigella groups in the mixture of two organisms. 2. The inhibitory effects of E.coli in the E.coli-Salmonella and the E.coli-Shigella mixture occurred from 4 hours incubation following the inoculation. 3. Even the complete inhibition of pathogenic enteric bacterial growth was noticed in the E.coli-Salmonella mixture at overnight incubation. 4. Among the diluted mixtures, 1:100, 1:1,000, and 1:10,000, survival rate of pathogenic enteric bacteria in the mixtures with E.coli showed least affected at the 1:1,000 dilution. 5. It was found that the antagonistic effect aganist groups of Salmonella-shigella was depending upon the groups of the genera.

• Korean Journal Plant Pathology
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• v.14 no.3
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• pp.268-277
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• 1998

The production of Korean ginseng, one of the most important medicinal root crops, is limited by many factors including soil sickness, root rots in fields as well as during storage prior to consumption. Although much research has been conducted on the diseases in field condition, little information is available on the control of postharvest roots rots. To obtain better management strategy of postharvest root rots in ginseng, biological control using antagonistic bacteria was attempted. Of 208 bacteria obtained form suppressive soil samples, 4 were selected based on the inhibitory effect on mycelial growth of two major causal fungi for postharvest root rots in ginseng, Botrytis cinerea and Fusarium solani. The culture filtrates of these bacterial antagonists greatly inhibited the conidial germination of both pathogenic fungi and produced abnormal morphology such as swollen germ tubes in F. solani and vacuolation of nongerminated conidia in B. cinerea. The population levels of bacterial antagonists on the ginseng roots were gradually increased up to 8 days of incubation. Postharvest root rots of ginseng caused by f. solani and B. cinerea were controlled in dipping tests in the ranges of 60∼80% by antagonistic Bacillus spp. obtained from suppressive soil. These results suggest that biological control using these antagonistic bacteria would be an alternative strategy to control postharvest root rots in ginseng.