• Microbiology and Biotechnology Letters
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• v.1 no.2
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• pp.89-92
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• 1973

In the previous paper the biological characteristics and some reaction mechanisms of Astradix-P, yeaststatic substance, were reported. Especially yeaststatic activity of Astradix-P was anta-gonistically inhibited by alkaline amino acids, arginine, lysine and histidine, which were added as a nitrogen source in the yeast growing medium. In this paper the effects of alkaline nitrogen containing substance and several vitamins on the yeaststatic activity were investigated. The antagonistic action of alkaline nitrogen containing substance; adenine and vitamins; thiamine, riboflavin, pyridoxin, cobalamin, nicotinic acid, folic acid, biotin, p-aminobenzoic acid, inositol, and pantothenic acid to Astradix-P were not observed, thus evidencing that the yeaststatic activity of Astradix-P was not inhibited by a alkaline nitrogen containing substance and several vitamins.

• Microbiology and Biotechnology Letters
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• v.18 no.4
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• pp.331-337
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• 1990

An antitumor antibiotic named B-1123 substance was isolated from the culture filtrate of a new isolate fungus identified as Aspergillus terreus. The fermentation yield reached about 23 mg per liter of the broth. The B-1123 substance, chlorine containing antibiotic, has the molecular formular of $C_{17}H_{12}0_7C_{12}$. Its structure was determined to be geodin by spectroscopic data. It is active against some Gram-positive bacteria and it prolongs the life span of mice inoculated with Ehrlich carcinoma.

• Korean Journal of Microbiology
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• v.12 no.4
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• pp.188-193
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• 1974

Effects of GA and IAA on the respiratory and photosynthetic activity of each growth stage during the synchronous culture of Chlorella ellipsodiea, were investigated. 1) GA ($2{\times}10^{-8}M$) affected most insignificantly on the respiratory activity of the stages Dn, Da, $L_1$, $L_2$, $L_3$-cells but only at $L_4$-cells treated with IAA($10^{-3}/M$) were promoted and $L_3$, $L_4$-cells were suppressed. With the treatment of GA-IAA the effects on respiration of eah stage cells were antagonistic. 2) Photosynthetic activity treated with GA during the each stage of Chlorella cells was promoted and IAA treated-cell were suppressed. The effect of GA-IAA upon the process of life cycle was also antagonistic. 3) It was revealed that respiratory and photosynthetic activity of Chlorella cells by the treatment of GA(($2{\times}10^{-8}M$) and IAA($10{\times}^{-3}/M$) had antogonistic effects.

• Journal of Life Science
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• v.13 no.3
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• pp.355-358
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• 2003

Various Trichoderma spp. were evaluated for the development of biofungicides to control soilborne pathogen, Rhiztonia solani, Various Trichoderma spp. were initially tested for their ability to inhibit growth of R. solani by inhibition zone test. Inhibition zones of 3∼5 mm toward R. solani were detected on PDA agar plates. The parasitic activity of strains, the activities of cell-wall-degrading enzymes such as glucanases and chitinases, were also evaluated. Highest activities of glucanase and chitinase were 3.5 U/ml and 0.9 U/ml, respectively, Isolated Trichoderma spp. also exhibited good growth with currently used agrochemicals, which represents that the isolated biofungicides can be mutually used with agrochemicals.

• Korean Journal of Organic Agriculture
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• v.5 no.1
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• pp.137-147
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• 1996

For the purpose of acquiring microbial agents that can be utilized to biologically control the major airborne diseases to apple trees, such as canker(Botryosphaeria dothidea), bitter rot(Glomerella cingulata), alternaria leaf spot(Alternaria mali), root rot(rosellinia necatrix), canker(Valsa ceratosperma) and gray mold rot(Botrytis cinerea), the effective microorgaisms were isolated, tested for antagonistic activity to the pathogens causing major diseases to apple trees and identifed. Screening of more than 5,000 species of microorganisms collected in nature for them antagonistic action to the pathogens causing 5 major diseases to apple trees resulted in selection of effective species. Out of the 11 species, one species designated as CAP134 demonstrated outstanding activity. The bacterial strain, CAP134 exerted antagonistic efficiency of 57% on an isolated strain and 40% on a donated strain of Botryosphaeria dothidea., 52% on an isolated strain and 46% on a purchased strain of Alternaria mali, 60% on Valsa ceratosperma 25% on Glomerella cingulata, and 64% Rosellinia necatrix. The CAP134 was identified as a bacterial strain to Bacillus subtilis ATCC 6633 based on morephology, culture conditions, and physio-biochemical characteristics.

• Korean Journal of Organic Agriculture
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• v.23 no.1
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• pp.133-148
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• 2015

Although several adverse effects have been increased in recent years, synthetic agro-chemicals have been widely used to control diseases on paprika. This research was conducted to isolate and to characterize the antagonistic microorganism to control major paprika diseases, gray mold rot, fruit and stem rot, phytophthora blight, sclerotium rot, and wilt disease. Analysis of the fatty acid and analysis of the 16S rDNA gene sequence revealed that YKJ2 isolated in this research belongs to a group of Burkholderia cepacia. Specially, 16S rDNA gene sequence of YKJ2 showed 99% of sequence similarity with B. cepacia. Observation through the optical microscope revealed that YKJ2 was effective on suppression of the spore germination and the hyphal growth of pathogens. YKJ2 treatment on pathogens induced marked morphological changes like hyphal swelling and degradation of cell wall. In the case of phytophthora blight, the zoosporangium formation was restrained. On the basis of the results of this study, we propose that an antagonistic microorganism, B. cepacia, found in this study naming as "B. cepacia strain YKJ2" and has great potential as one of biological control agents against major diseases of paprika.

• Journal of Ginseng Research
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• v.28 no.1
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• pp.67-70
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• 2004

Bacillus subtilis B-4228 selected from ginseng field soil for prevention of rusty root was tested for the control of ginseng root rot. In petri-plate dual culture, mycelial growth of Cylindrocarpon destructans was inhibited by B-4228 and hyphal swelling of C. destructans was occurred. In pot experiment with C. destructans-contaminated soil B-4228 dipping of ginseng seedling showed significant preventive effect of root rot (p=0.01), percent healthy root 82% and 20% for treatment and control, root rot rate 6% and 50.4%, respectively.

• Research in Plant Disease
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• v.16 no.2
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• pp.163-169
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• 2010

To screen for potential biocontrol agents against postharvest disease of garlics caused by Penicillium hirsutum, a total of 1292 isolates were isolated from the rhizoshere or rhizoplane of Allium species. Among them, S59-4 isolate was selected as a potential biocontrol agent by in vivo wounded garlic bulb assay. The isolate was identified as Pantoea agglomerans (Pa59-4) through Biolog system. Pa59-4 did not inhibit the mycelial growth of P. hirsutum in dual-culture with P. hirsutum on tryptic soy agar. In order to elucidate mode of action of Pa59-4 on biological control, nutrient competition between Pa59-4 and P. hirsutum was investigated by the simple method using tissue culture plates with cylinder inserts containing defusing membrane reported by Janisiewicz et al. (2000). The results showed that Pa59-4 effectively suppressed spore germination and mycelial growth of blue mold in the low concentration (0.5%) of garlic juice, but it did not suppress those of blue mold in the high concentration (5%) of garlic juice. This result suggests that the mechanism in biocontrol of garlic blue mold by Pa 59-4 may be involved in nutrient competition with P. hirsutum on garlic bulbs.

• Microbiology and Biotechnology Letters
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• v.29 no.3
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• pp.142-148
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• 2001

An indigenous antagonistic bacterium Bacillus sp. 7079 was isolated from a local soil sampled at Kyongju area in Korea . The strain has strong antagonistic ability which was originated from multifunctional mechanisms of chitinase and antibiotic and is a powerful antagonistic biocontrol agent against red-pepper rotting fungus Phytophthora capsici and Wilt fungus Fusarium oxysporum. The chitinase might degrade the cell wasll for Fusarium species. The selected Bacilus sp. 7079 was identified as a Bacillus amyloliquefaciens 7079. The maximal production of the chitinase from B, amyloliquefaciens 7079 were obtained in chitin-yeast extract medium containing 0.7%, $K_2$$HPO_4$, $0.2KH_2$$PO_4$, 0.1% ($NH_4$)$_2$$SO_4$, 0.05% sodium cirate, 0.01% $MgSO_4$$7H_2$O, 0.1% yeast extract and 0.1% colloidal chitin after cultivation of 3 days at pH 7.0 and $30^{\circ}C$. The best carbon and nitrogen sources for the production of the chitinase from B amyloliquefaciens 7079 were determined to be 0.1% colloi- dal chitin and 0.15% proteose peptone NO 3 respectively, The antagonistic activity of B amyloliquefaciens 7079 was confirmed using P. capsici by in vivo pot test with red-pepper plant.

• The Korean Journal of Pesticide Science
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• v.21 no.1
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• pp.90-96
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• 2017

Gray mold disease, cause by Botrytis cinerea, occurs severe damage on varieties of fruit and vegetable production, and have no a critical control method. In case of chemicals control, it is a trigger emergence of drug resistance strains due to using them continuously. In addition, the pathogen is difficult to control naturally because it is possible to survive regardless of host status. In this study, microorganisms were isolated from tomato flower and hive samples and in order to select suitable microbial control agents for tomato gray mold disease. During six-months study, we isolated 1,004 isolates from flower and 925 isolates from pollinator hive samples. Among them, 6 strains were selected based on result of antifungal activity test. The selected strains showed not only strong antifungal activity against gray mold pathogen, but also cellulase and protease enzyme activities. The selected strains were identified as Paenibacillus polymyxa. In plant assay, P. polymyxa prevented the gray mold disease occurrence near 75%.