• 한국잡초학회지
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• 제18권2호
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• pp.161-170
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• 1998

Fenoxaprop-P-ethyl에 대한 bentazon의 길항작용기작을 검정하기 위하여 4엽기의 벼와 피를 대상으로 bentazon 혼합처리에서 나타나는 fenoxaprop-P-ethyl의 흡수, 이행, 대사 및 작용점의 활성 변화를 조사하였다. Fenoxaprop-P-ethyl에 대하여 벼와 피의 지상부에서 생육억제가 크게 나타났다. Fenoxaprop-P-ethyl 단독처리에 있어서 두 초종 모두에서 처리 직후부터 빠른 속도로 약제가 흡수되어, 총 흡수량의 90%이상이 약제처리 6시간 이내에 이루어졌으며, 처리 24시간까지 흡수량의 약 30%가 처리엽의 상, 하위조직으로 이행되었다. Ethyl ester형으로 처리된 약제는 신속히 acid형으로 전환되었으며, 처리 24시간 후부터는 acid형이 conjugate형의 대사물로 전환되었다. 그러나 bentazon에 의한 fenoxaprop-P-ethyl의 흡수, 이행 및 대사활성의 변화는 인정되지 않았다. In vitro ACCase의 활성은 벼와 피 에서 각각 26.5 및 23.2nmol/min/mg protein으로 나타났다. 이 효소 활성의 50% 저해농도에 있어서 fenoxaprop-P-ethyl 단독처리와 bentazon 혼합처리 사이에 유의성은 인정되지 않았다. 그러나 bentazon 처리에 의하여 in vivo ACCase 활성의 감소와 엽록체 thylakoid에서 전자전달의 억제가 나타났다. 따라서 fenoxaprop-P-ethyl에 대한 bentazon의 길항작용기작은 bentazon이 fenoxaprop-P-ethyl 작용점의 활성에 직접적으로 관여하는 것이 아니라, 엽록체 구조 및 활성 저해에 의한 fenoxaprop-P-ethyl의 작용점 감소를 통하여 간접적으로 fenoxaprop-P-ethyl의 활성을 억제하는 것으로 판단된다.

• 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.

• Journal of Plant Biology
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• 제9권1_2호
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• pp.17-21
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• 1966

The mutual relationships of boron, Ca and sucrose were studied in relation to in vitro pollen growth and pollen bursting, by using conventient pollen from Crinum asiaticum for experiment. Crinum pollen are paticularly sensitive to Ca. Addition of very small amount of boron to cultural media was apparently synergistic to the action of sucrose and Ca in pollen germination and tube elongation. This action was extended to a higher level of boron concentraton. Combined application of boron, Ca and sucrose always gave the better results in pollen growth and protection against pollen bursting much more than when used singly. This indicated that there is a direct relationship between better growth of pollen and increased rigidity of pollen cell wall. A higher level of Ca concentration tended to increase bursting rate of pollen grains and decrease that of pollen tubes, while boron always depressed the rate of bursting. This was considered due to increased failure in pollen germination at high level of Ca that favors pollen tube elongation. The fact that Ca show an antagonistic effect on the suppressive action of high level of boron in pollen growth and shows different effect in response to pollen bursting from boron, suggested mode of Ca and boron action in the presence of sucrose is quiate different, although to increase in rigidity of pollen cell wall by them is in common nature. It was postulated therefore that Ca acts on pectins of pollen cell wall largely as "non-metabolic" and boron as "metabolic" promoter is pollen growth and protecting pollen bursting, since boron and Ca have common nature in strengthening the pollen cell wall but act differently.but act differently.

• Journal of Microbiology and Biotechnology
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• 제10권6호
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• pp.811-816
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• 2000

An antagonistic bacterium PM-1 which strongly inhyibits the growth of Pyricularia oryzae was isolated and identified as paenibacillus macerans. The antifungal substances of the strain PM-1 showed the broad antifungal spectra against P.oryzae races. Relating to the localization test, it was found that the antifungal substances existed not only in the cytoplasm but also in the culture supernatant, and importantly the antifungal activity of the latter was stronger than that of the former. The extracellular antifungal substances were extremely heat-stable up to $121^{\circ}C$ for 15 min. The substances were optimally produced at $20^{\circ}C$ and pH 10.0 in a potato dextrose broth. The culture filtrate of the strain PM-1 caused a partial swelling of the mycelia of P.oryzae, and it prevents the normal growth of the fungus as well. This result suggested that the antifungal substances secreted by the strain PM-1 potentially inhibited the germination of P.oryzae.

• The Plant Pathology Journal
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• 제26권4호
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• pp.340-345
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• 2010

Two similar microbial fungicides (termed as MA and MB) developed in a Korean biopesticide company were analyzed and compared each other in their biocontrol activities against the phytophthora blight of chili pepper caused by Phytophthora capsici. MA and MB contained the microbe Paenibacillus polymyxa and Bacillus subtilis, respectively, with concentrations over those posted on the microbial products. In comparison of the isolated microbes (termed as MAP from MA and MBB from MB) in the antagonistic activities against P. capsici was effective, prominently against zoospore germination, while MBB only significantly inhibited the mycelia growth of the pathogen. Some effectiveness of MAP and MBB was noted in the inhibition of zoosporangium formation and zoospore release from zoosporangia; however, no such large difference between MAP and MBB was noted. In a pot experiment, MA reduced the severity of the phytophthora blight more than MB, suggesting that the disease control efficacy would be more attributable to the inhibition of zoospore germination than mycelia growth of P. capsici. These results also suggest that the similar microbes MA and MB targeting different points in the life cycle of the pathogen differ in the disease control efficacies. Therefore, to develop microbial fungicides it is required to examine the targeting points in the pathogen's life cycle as well as the action mode of antagonistic microorganisms.

• 한국균학회지
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• 제44권1호
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• pp.36-47
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• 2016

본 연구는 식물 근권에서 분리한 유용미생물 PA1, PA2, PA4, PA5, PA12 의 식물 생장 촉진능력과 식물 병원성 진균인 Colletotrichum acutatum, C. coccodes, C. gloeosporioides, C. dematium, Botrytis cinerea, Rhizoctonia solani, Sclerotinia minor 그리고 Fusarium sp.에 대한 생장억제능력을 평가하는데 그 목적이 있다. In vitro 실험에서 유용미생물의 식물 병원성 진균의 생장억제 능력을 확인하기 위해 세균배지인 TSA 배지와 곰팡이 배지인 PDA배지, 그리고 TSA와 PDA배지를 각각 50%씩 혼합한 배지(v/v, 1:1)에서 대치배양을 실시하였다. 그 결과 PDA배지에서는 PA2가 C. coccodes에 대해 65.5%로 가장 높은 억제능력을 보였으며, TSA배지에서는 PA2가 S. minor에 대해 96.5%로 가장 높은 억제력을 보였다. 또한 PDA와 TSA를 혼합한 배지에서는 PA2가 C. acutatum에 대해 58.5%로 가장 높은 억제능력을 보였다. 분리한 5균주 모두에서 식물병원성 진균에 대하여 생물적 방제 효과가 있음을 확인하였다. 또한 식물생장 촉진능력을 유발하는 원인물질을 탐색하기 위해 siderophore, protease, chitinase, hydrogen cyanide (HCN) 생성 유무를 확인하였고, phosphate solubilizing 실험을 실시하였다. 본 연구에서 사용된 유용미생물 5균주를 16s rDNA sequencing 결과 PA1, PA2는 Bacillus subtilis, PA4, PA5, PA12 각각 Bacillus altitudinis, Paenibacillus polymyxa, Bacillus amyloliquefaciens로 동정되었다.

• 한국응용곤충학회지
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• 제22권2호
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• pp.147-159
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• 1983

In general, herbicides have been classified according to selectivity, mobility. time of application, methods of application, mode of action and chemical property and structure. However, there was no generally accepted classification system for practical use in the field. The primary processes affected by the majority of herbicides are the growth process through cell elongation and/or cell division, the photosynthetic process specifically the light reaction, the oxidative phosphorylation and the integrity of the membrane systems. The usual approach in the study of the mechanism by which herbicides kill or inhibit the growth of plants is to initially determine the morphological phototoxicity systems, The mechanism by which a herbicide kills a plant or suppresses its development is actually the resultant effect of primary and secondary(or side) effects. In most instances, the death of the plant is due to the secondary effects. To induce the desired response, a herbicide must be able to gain entry into the plants and once inside, to be transported within the plant to its site(s) of activity in concentrations great enough. Obstacles to the entry and movement of herbicides in plants are generally classified by leaf and soil obstacles, translocation obstacles and biochemical obstacles, and these obstacles are also strongly influenced by plant species and by environmental factors such as light, temperature, rainfall and relative humidity. And hence, in most instances, results obtained from laboratory or greenhous vary from those of field experiment. Author attempted to classify herbicides from the field experiment using the two-dimensional ordination analysis to obtain practical information for selecting effective herbicides or to choose effective herbicide combinations for increasing herbicidal efficacy or reducing the chemical cost. Based on this two-dimensional diagram, desired herbicides or combinations were selected and further investigated for the interaction effects whether these combinations are synergistic, additive or antagonistic. From the results, it was concluded that these new approach could possibly be give more comprehensive informations about effective use of herbicide than any other systems.

• 한국균학회지
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• 제22권1호
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• pp.50-61
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• 1994

토양으로부터 분리한 380개체의 균주 중 Fusarium solani에 대해 길항능력이 있는 방선균 및 세균 42개 균주로부터 길항작용이 큰 균주로 CHA 1과 5-PFHR 6을 공시하여 동정한 결과 각각 Promicromonospora sp.와 Pseudomonas pseudoalcaligenes로 동정되었다. PDA 평판배지상에서 두 균주는 모두 F. solani의 저해작용으로 균사의 길이 생장억제, 비정상적인 균사의 분지, 세포벽 분해에 의한 돌기형성 등이 관찰되었다. F. solani 포자발아에 미치는 길항균주의 배양여과액의 작용으로 감자즙액 배지나 nutrient broth에 배양한 여과액은 포자발아 억제력이 높아 14.3%의 낮은 발아율을 보였으며, 토양침출액 단독 또는 두 영양배지에 토양침출액을 첨가하여 준비한 배양 여과액에서의 발아율은 85% 이상으로 포자발아가 촉진되었으나 S-PFHR 6의 경우 두 영양배지에 소량의 토양침출액을 첨가한 배앙여과액에서 4%의 발아율을 보였다. 자연토양에서 대형포자는 19.4%, 후막포자는 17.7%가 발아하였으나 증기살균 토양에서의 발아율은 79.7% 이상으로 증가하였다. 자연토양에 공시길항균 CHA 1과 S-PFHR 6의 균체를 처리하면 토양 정균력이 증가되어 F. solani의 대형 포자 발아율은 각 처리구에서 각각 14.7%, 11.7%로 감소하였다. 길항균을 처리한 토양에 glucose와 asparagine을 처리하면 토양의 정균력이 점차 해소되어 대형포자의 발아율은 48.0% 이상으로 증가하였다. 공시균주의 2차 대사산물에 의한 길항작용으로 두 균주의 배양여과액을 토양에 처리한 경우 CHA 1의 배앙여과액을 처리한 토양에서의 F. solani 대형포자의 발아율은 9.3%, 5-PFHR 6 처리구에서의 발아율은 38.0%가 되었다. F. solani의 후막포자는 공시길한균주의 균체나 배양여과액 처리구에서의 발아율이 자연토양에서의 발아율보다 낮았으며 이러한 현상은 영앙원을 첨가해 주어도 변하지 않았다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2016년도 춘계학술대회 및 임시총회
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• pp.13-13
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• 2016

Insects constitute the largest and most diverse group of animals in the world. They also serve as the hosts or nutrient sources for an immense assemblage of pathogens, parasites, and predators. More than 700 fungal species from 100 genera have adopted an entomopathogenic lifestyle. Although entomopathogenic fungi were studied as only biocontrol agents against a variety of pests in various countries, it has been recently focused their additional roles in nature. They are antagonists to/against plant pathogens, endophytes, and possibly even plant growth promoting agents. The potential antimicrobial effect against fungal plant pathogens by an isolate of entomopathogenic fungi including Beauveria bassiana, Lecanicillium spp., and Isaria fumosorosea have been reported since late 1990s, but wasn't reported pathogenicity of the isolate against pests. Later, a Canadian Lecanicillium sp. isolate and L. longisporium isolated from Vertalec$^{(R)}$ showed simultaneous control effect against both aphid and cucumber powder mildew. Therefore, the antimicrobial activities of 342 fungi isolates collected from various regions and conditions in Korea were evaluated against plant pathogenic fungus Botrytis cinerea using dual culture technique on agar plate. As a result, 186 isolates (54.4%) shown the antifungal activity against B. cinerea. The culture filtrates of selected fungi completely suppressed the growth of the microorganisms, indicating that suppression was due to the presence of antimicrobial substances in the culture filtrate. Mode of action of these fungi against insect involves the attachment of conidia to the insect cuticle, followed by germination, cuticle penetration, and internal dissemination throughout the insect. During infection process, secreted enzymes, proteinous toxins, and/or secondary metabolites secreted by entomopathogenic fungi can be used to overcome the host immune system, modify host behavior, and defend host resources. Recently, secondary metabolites isolated from entomopathogenic fungi have been reported as potential bioactive substances. Generally, most of bioactive substances produced by entomopathogenic fungi have reported low molecular weight (lower than 1,000 g/mol) as peptide and, in contrast the high molecular weight fungal bioactive substances are rare. Most substances based on entomopathogenic fungi were shown antimicrobial activity with narrow control ranges. In our study we analyzed the antimicrobial substances having antagonistic effects to B. cinerea. Antimicrobial substances in our fungal culture filtrates showed high thermostability, high stability to proteolytic enzymes, and hydrophilicity and their molecular weights were differed from substance. In conclusion, entomopathogenic fungi showed pathogenicity against insect pests and culture filtrate of the fungi also shown to antimicrobial activity. In the future, we can use the entomopathogenic fungi and its secondary metabolites to control both insect pest control and plant pathogenic fungi simultaneously.

• 한국식품위생안전성학회지
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• 제19권3호
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• pp.151-160
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• 2004

우리나라 고유의 전통발효 식품인 메주로부터 항리스테리아 활성을 나타내는 유산균을 분리한 후 동정한 결과 E. faecium MJ5-14로 명명되었으며, 이들의 박테리오신은 MRS broth 중에 $37^{\circ}C$에서 12-18시간 배양하는 동안 최대의 활성을 나타내었다. L. monocytogenes KCTC 3569와 KCTC 3710 및 L. ivanovii subsp. ivanovii에 대한 박테리오신의 활성은 640 BU/mL이었고, L. innocua ATCC 33090, L. ivanovii ATCC 19119, L. grayi KCTC 3581 및 L. seeliger KCTC 3591에 대한 활성은 1280 BU/mL으로 나타났다. L. monovytogenes KCTC 3569와 E. faecium MJ5-14을 혼합 배양한 경우 L. monocytogenes의 감소 효과는 $25^{\circ}C$이하 보다는 E. faecium MJ5-14의 박테리오신 생산 최적 온도인 $37^{\circ}C$에서 더 높게 나타났으며, E. faecium MJ15-14의 박테리오신 항균 효과는 L. monocytogenes KCTC 3569의 초기 균수와 첨가한 박테리오신의 양에 따라 좌우하는 L. monocytogenes의 초기 균수가 적고, 박테리오신의 첨가량이 많을수록 항균효과가 높아짐을 확인하였다. 또한 박테리오신 70 BU/mL 첨가에 의한 항균 효과는 균 증식이 활발한 대수증식기 중반 이후 보다는 유도기 내지는 대수증식기 초반부에 더 크게 나타났다. 한편, 박테리오신 25 BU/mL을 첨가에 의해서 L. monocytogenes KCTC 3569 새포벽의 일부가 얇아지고, 50 BU/mL 이상의 농도에 의해선 세포막이 파괴되면서 세포 내용물의 유출 현상이 관찰되었다.