• The Korean Journal of Ecology
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• 제23권2호
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• pp.181-185
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• 2000

This study was carried out to see whether Gastrophysa viridula (Degeer) (Coleoptera : Chrysomelidae) could be used as a biological control agent for Rumex obtusifolius L., with human manipulation of the beetle population. The study was consisted of three experimental sets : Wet-Dry experiment (the wet weight Vs dry weight relationship of Rumex obtusifolius L.), Greenhouse feeding experiment, and Field experiment. There was a significant correlation between the total wet and dry weight of Rumex obtusifolius as follows : Total dry weight : -0.23542+ (0.17514${\times}$Total wet weight) ($R^2$=0.9317, p=0.047, T=16.927 (dF=21)). In the Greenhouse feeding experiment, the result was very promising. The relationship between the density unit of the beetles and the growth of the plant is given below (20 day) : Plant growth =105.8+(-34.4${\times}$Density unit) ($R^2$=0.76, p=0.13). A repeated introduction of the beetle population into the field vegetation of R. obtusifolius from April to October is suggested to see the beetle's grazing ability on the plant. This study shows that the potential grazing power of the beetle on Rumex obtusifolius was enough to defoliate the plants, but it was able to recover from its root reserves. The practical question remains as to whether repeated additions (by man) of the beetles to Rumex obtusifolius could eliminate them.

• 한국균학회지
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• 제49권4호
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• pp.497-505
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• 2021

다양한 지역에서 채취한 참당귀(Angelica gigas Nakai)의 잎, 줄기, 뿌리에서 내생균을 분리하였다. 내생균 균주는 형태적특징과 ITS (internal transcribed spacer) 지역의 염기서열을 이용하여 동정하였다. 총 35종의 내생균이 동정되었다. 내생균의 다양성은 참당귀의 조직에 따라 다르게 나타났다. 분리된 내생균은 참당귀 점무늬병균 Phoma sp. Y11 균주와 대치배양하여 항균활성을 측정하였다. 총 14종의내생균이균주 Y11에대해억제효과를나타내었다. 본 연구는 참당귀에서 분리한 내생균이 참당귀의 점무늬병에 대한 생물학적 방제제로 사용될 수 있다는 것을 제시하고 있다.

• The Plant Pathology Journal
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• 제38권1호
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• pp.33-45
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• 2022

To screen antagonistic fungi against plant pathogens, dual culture assay (DCA) and culture filtrate assay (CFA) were performed with unknown soil-born fungi. Among the different fungi isolated and screened from the soil, fungal isolate ANU-301 successfully inhibited growth of different plant pathogenic fungi, Colletotrichum acutatum, Alternaria alternata, and Fusarium oxysporum, in DCA and CFA. Morphological characteristics and rDNA internal transcribed spacer sequence analysis identified ANU-301 as Aspergillus terreus. Inoculation of tomato plants with Fusarium oxysporum f. sp. lycopersici (FOL) induced severe wilting symptom; however, co-inoculation with ANU-301 significantly enhanced resistance of tomato plants against FOL. In addition, culture filtrate (CF) of ANU-301 not only showed bacterial growth inhibition activity against Dickeya chrysanthemi (Dc), but also demonstrated protective effect in potato tuber against soft rot disease. Gas chromatography-tandem mass spectrometry analysis of CF of ANU-301 identified 2,4-bis(1-methyl-1-phenylethyl)-phenol (MPP) as the most abundant compound. MPP inhibited growth of Dc, but not of FOL, in a dose-dependent manner, and protected potato tuber from the soft rot disease induced by Dc. In conclusion, Aspergillus terreus ANU-301 could be used and further tested as a potential biological control agent.

• Journal of Microbiology and Biotechnology
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• 제5권6호
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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 Korean Biological Nursing Science
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• 제18권3호
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• pp.185-191
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• 2016

Purpose: The purpose of this study is to understand the effect of taking calcium/vitamin D supplements and performing Taekkyeon exercises on the frailty of the elderly targeting a vulnerable senior social group. Methods: A total of 124 people aged 65 and older consisting of 60 persons in the experimental group, and 64 persons in the control group participated in this study, and this study is a non-equivalent control group pre/post-test design quasi-experimental study. This study analyzed the homogeneity between the experimental group and the control group using a chi-square test and t-test while analyzing the difference in the degree of frailty and bone density with the practice of Taekkyeon and a calcium agent using t-test and GEE. Results: The study results showed that the frailty and bone density of the experimental group significantly improved. Conclusion: Through this study, it was confirmed that calcium/vitamin D intake and Taekkyeon exercises were an effective intervention which strengthened the elderly's physical condition.

• 식물병연구
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• 제9권3호
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• pp.174-178
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• 2003

콩 탄저병의 생물학적 방제를 위하여 병원균 Colletotrichum truncatum과 C. gloeosporioieds에 대한 길항세균 Pseudomonas sp.를 분리 동정하였다. Pseudomonas sp.의 균사생장 억제효과는 탄저병 살균제 benomyl, fluazinam과 비슷하였으며, 콩에 대한 병원성은 거의 없었다. Pseudomonas sp. 의 종자처리는 C. truncatum 을 접종한 콩 종자의 출현율을 현저히 증가시켰고, 경엽처리한 경우 잔효성은 낮았지만 처리 2주 후의 방제효과는 benomyl, fluazinam과 비슷하게 높았다.

• The Plant Pathology Journal
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• 제27권1호
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• pp.78-84
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• 2011

Antagonistic rhizobacteria, more specifically fluorescent pseudomonads and certain species of Bacillus, are known as biocontrol agents of fungal root diseases of agronomic crops. In this study, 144 bacteria were isolated from cucumber rhizosphere and screened as potential biological control agents against Phytophthora drechsleri, the causal agent of cucumber root rot, in vitro condition. Non-volatile compounds of 23 isolates showed noticeable inhibition zone (> 30%) against P. drechsleri, whereas volatile compounds of 7 isolates could prevent more than 30% of the mycelial growth of the fungus. All promising isolates, except of Pseudomonas flourescens V69, promoted significantly plant growth under in vitro condition. P. flourescens CV69 and V11 exhibited the highest colonization on the root. Results of the greenhouse studies showed that a reduction in disease incidence by use of some strains, and particularly use of strains CV6 and V11 as a soil treatment, exhibited a reduction in disease incidence so that suppressed disease by 85.71 and 69.39% respectively. Pseudomonas flourescens CV6 significantly suppressed disease in comparison to Ridomil fungicide. The use of mixture bacterial strains in the soil inoculated by the fungus resulting in falling down the most of the plants which didn't show significant difference with infected control soils without bacteria.

• Journal of Ginseng Research
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• 제39권3호
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• pp.213-220
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• 2015

Background: Korean ginseng (Panax ginseng Meyer) is a perennial herb prone to various root diseases, with Phytophthora cactorum being considered one of the most dreaded pathogens. P. cactorum causes foliar blight and root rot. Although chemical pesticides are available for disease control, attention has been shifted to viable, eco-friendly, and cost-effective biological means such as plant growth-promoting rhizobacteria (PGPR) for control of diseases. Methods: Native Bacillus amyloliquefaciens strain HK34 was isolated from wild ginseng and assessed as a biological control agent for ginseng. Leaves from plants treated with HK34 were analyzed for induced systemic resistance (ISR) against P. cactorum in square plate assay. Treated plants were verified for differential expression of defense-related marker genes using quantitative reverse transcription polymerase chain reaction. Results: A total of 78 native rhizosphere bacilli from wild P. ginseng were isolated. One of the root-associated bacteria identified as B. amyloliquefaciens strain HK34 effectively induced resistance against P. cactorum when applied as soil drench once (99.1% disease control) and as a priming treatment two times in the early stages (83.9% disease control). A similar result was observed in the leaf samples of plants under field conditions, where the percentage of disease control was 85.6%. Significant upregulation of the genes PgPR10, PgPR5, and PgCAT in the leaves of plants treated with HK34 was observed against P. cactorum compared with untreated controls and only pathogen-treated plants. Conclusion: The results of this study indicate HK34 as a potential biocontrol agent eliciting ISR in ginseng against P. cactorum.

• 농업과학연구
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• 제35권2호
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• pp.127-136
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• 2008

곤충병원성 곰팡이인 Beauveria bassiana는 미생물 살충제로서 다양한 해충들을 방제하는데 사용해오고 있다. 최근에 B. bassiana TBI-1균주가 두점박이응애, 온실가루이에 살충효과가 있는 것으로 보고되었다. 생물학적 방제 인자인 B. bassiana TBI-1를 목화진딧물에도 어느 정도의 살충활성을 나타내었다. B. bassiana TBI-1 균주를 처리한 후 일주일 동안 평균 진딧물의 증가율은 0.21로 나타났으나 처리하지 않은 대조군에서는 0.24의 증가율로 약간 높게 나타나 보였다. 이러한 결과에서 백강균의 처리구에서 진딧물의 평가 증가율이 0.03 낮게 나타나는 것을 알 수 있었다. 또한 오이 잎에 B. bassiana TBI-1 균주에 의하여 붉은빛 곰팡이의 형태로 죽은 진딧물의 죽은 흔적을 육안으로 확인할 수 있었다. 적정농도로 B. bassiana TBI-1을 처리하면 목화진딧물의 개체군 증가율을 현저히 감소시킴으로 효과적으로 진딧물을 방제할 수 있을 것이다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.240-244
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• 2003

A novel integrated method for increasing dissolved oxygen concentration in culture media has been developed. It involves adding hydrogen peroxide to the medium, which is then decomposed to oxygen and water by catalase and adding vegetable oil to the medium as antifoam agent and oxygen vector. A new apparatus for automated addition of hydrogen peroxide to the bioreactor to keep the dissolved oxygen concentration constant over the range $10-100%\;{\pm}\;5%$ was tested. A significant increase (over threefold) of cultivation time was obtained while the dissolved oxygen concentration remained stable ($30%\;{\pm}\;5%$). Therefore, use of corn oil mixed with Ca-stearate as oxygen vector and antifoam and hydrogen peroxide as oxygen source to control excessive foam that was generated by microorganism biosurfactant, GB16-BS produced at Bacillus sp. GB16 cultivation was appropriate for stable cultivation.