• The Plant Pathology Journal
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• 제16권4호
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• pp.227-230
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• 2000

A total of 90 isolates of Fusarium oxysporum f.sp. melonis, the causal agent of oriental melon (Cucumis melo var. makuwa) wilt, was isolated from symptomatic tissues of oriental melon from 4 provinces in Korea. These isolates were grouped into vegetative compatibility groups (VCGs) by demonstrating heterokaryosis through complementation using nitrate nonutilizing (nit) mutants. No self-incompatibility was observed in any of isolates. All isolates were grouped into 3 VCGs ; A, B, and C. iSOLATES BELONGING TO VCG A and VCG B accounted for 87% and 91% of the fungal population collected in 1991 and 1993, respectively. As the increment of cultivation period in the same field, the proportion of isolates belonging to VCG B increased whereas that of isolates belonging to VCG A decreased. Mean virulence of a total population increased as the increment of cultivation period in the same field. Isolates belonging to VCG B showed the highest increment of virulence. These data suggest that replanting of a host plant in the same field may cause increase of virulence in the pathogens. Furthermore, virulence of F. oxysporum f.sp. melonis isolates is related to the VCGs.

• 한국식물병리학회지
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• 제2권3호
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• pp.158-164
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• 1986

Fusarium oxysporum f. sp. fragariae에 의한 딸기 시들음병에 감염된 딸기 식물의 병태조직학적 특징을 광학현미경으로 조사한 결과 자연 또는 인공 감염된 뿌리, 관부, 잎자루 및 포복지의 도관내에는 본 병균의 균사와 대형, 소형 분생포자가 관찰되었으며, 이들 균체에 의한 도관의 폐쇄와 유관속내에 형성된 강(Cavity)이 관찰되었으나 다른 분화형에서 볼 수 있는 도관유조직의 비대현상, 분충체 및 pectin 물질에 의한 도관폐쇄는 관찰할 수 없었다. 따라서 딸기 시들음병의 위조발생은 균체에 의한 도관의 폐쇄가 중요한 요인으로 생각되었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제18권2호
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• pp.125-129
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• 2009

Entomopathogenic fungi were isolated directly from a cadaver of adult Monochamus alternatus supporting fungal sporulation, using a semi-selective medium and then screened several fungal colonies. The pathogenicity of each fungus was tested using oak longicorn beetle, Moechotypa diphysis, as substitutive insect. As the result, only one of them showed high pathogenicity against M. diphysis, with up to 100% mortality within 21 days of inoculation. Selected fungus was named as MaW1 and identified by Beauveria bassiana using microscopic examination and DNA analysis. Pathogenicity was also evaluated to M. alternatus.

• Mycobiology
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• 제32권1호
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• pp.47-53
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• 2004

Pseudomonas fluorescens 1-94 induced systemic resistance in chickpea against Fusarium wilt of chickpea caused by Fusarium oxysporum f. sp. ciceri by the synthesis and accumulation of phenolic compounds, phenylalanine ammonia lyase(PAL) and pathogenesis related(PR) proteins(chitinase, $\beta$-1,3-glucanase and peroxidase). Time-course accumulation of these enzymes in chickpea plants inoculated with P. fluorescens was significantly(LSD, P=0.05) higher than control. Maximum activities of PR-proteins were recorded at 3 days after inoculation in all induced plants; thereafter, the activity decreased progressively. Five PR peroxidases detected in induced chickpea plants. Molecular mass of these purified peroxidases was 20, 29, 43, 66 and 97 kDa. Purified peroxidases showed antifungal activity against plant pathogenic fungi.

• The Plant Pathology Journal
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• 제27권3호
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• pp.280-284
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• 2011

Fusarium wilt of banana caused by Fusarium oxysporum f. sp. cubense is widespread in Indonesia. However, the distribution of tropical race 4 strains has not been well studied. Thirty nine isolates of F. oxysporum f. sp. cubense were collected from Java and 7 isolates were from Sumatera, Bangka, and Kalimantan. All isolates produced volatile odor when grown on steamed rice. These isolates were further tested for their vegetative compatibility with nitM testers of 20 reported vegetative compatibility groups representing strains that belong to race 1, 2, and 4. Three isolates formed heterokaryons with nitM testers belong to race 1, 11 isolates with race 4, and the rest did not form heterokaryons with all nitM testers used. F. oxysporum f. sp. cubense tropical race 4 specific primer pair was used to amplify a 1400 bp fragment of tropical race 4 DNA. Seven isolates (Bnt2, Mln1, Srg1, Bgl3, Bgl6, Lmp1, and Kjg1) produced the 1400 bp amplification product were therefore tropical race 4.

• The Plant Pathology Journal
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• 제24권2호
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• pp.159-163
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• 2008

Accurate identification of pine wood nematode, Bursaphelenchus xylophilus is a prerequisite to diagnose the pine wilt disease. However, a fungivorous nematode, B. mucronatus is highly similar to B. xylophilus and it is difficult to differentiate these two species by morphological features. A molecular diagnosis method, ITSRFLP was applied for the identification of B. xylophilus and B. mucronatus from Korea. Genomic DNA was extracted from a single individual nematode and ITS DNA was amplified by PCR. The size of PCR product was approximately 900bp and the sequence data were obtained after cloning. Amplified ITS was digested by 5 different restriction enzymes (Rsa I, Hae III, Msp I, Hinf I, and Alu I) and provided a discriminatory profile for B. xylophilus and B. mucronatus. Besides, B. mucro- natus was determined to have 2 different genotypes, East Asian type and European type also clearly separated by Rsa I and Hae III digestion. European type of B. mucronatus is recently collected from Pinus koraiensis and has not been reported before. ITS sequnce data were analyzed by Restriction Mapper program and the result supported ITS-RFLP pattern. These data indicated that PCRRFLP method is an accurate and simple way for identification of Bursaphelenchus species.

• Applied Biological Chemistry
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• 제31권4호
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• pp.346-350
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• 1988

한국재래식간장에서 분리한 특향생성 Bacillus sp.의 NTG 변이주를 모균주로하여 자외선에 의해 2차 돌연변이시킴으로써 amylase, protease의 생산성이 증강된 우량간장 발효균주를 개발할 수 있었다. 변이주는 모균주에 비해 amylase의 경우 58%, protease의 경우 41% 정도 증강시킬 수 있었으며 그 생성효소들은 최적반응 pH, 최적반응온도 등 효소학적 특성이 거의 유사하였다. 5M의 고농도 식염용액에서도 그 작용이 크게 저하되지 않았으며 효소생산농도 2M정도까지는 별다른 영향을 받지 않았다.

• 한국응용곤충학회지
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• 제40권2호
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• pp.149-153
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• 2001

Fungus gnats, Bradysia spp.의 기주를 조사한 결과 오이, 멜론, 수박, 애호박, 토마토, 고추, 파프리카, 백합, 카네이션, 장미, 거베라, 국화, 호접란, 글라디오러스, 생강, 천궁, 작두콩, 신선초, 등굴레, 소나무, 해송 등 21종이 조사되었고 이들 유충은 작물의 지제부나 뿌리근권을 가해하여 뿌리절단, 줄기내 침입 등으로 생육저해, 시들음 증상, 식물체 고사의 원인이 된다.

• 한국환경과학회지
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• 제21권6호
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• pp.695-704
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• 2012

The application of disinfection models on the plasma process was investigated. Nine empirical models were used to find an optimum model. The variation of parameters in model according to the operating conditions (first voltage, second voltage, air flow rate, pH) were investigated in order to explain the disinfection model. In this experiment, the DBD (dielectric barrier discharge) plasma reactor was used to inactivate Ralstonia Solanacearum which cause wilt in tomato plantation. Optimum disinfection models were chosen among the nine models by the application of statistical SSE (sum of squared error), RMSE (root mean sum of squared error), $r^2$ values on the experimental data using the GInaFiT software in Microsoft Excel. The optimum model was shown as Weibull+talil model followed by Log-linear+ Shoulder+Tail model. Two models were applied to the experimental data according to the variation of the operating conditions. In Weibull+talil model, Log10($N_o$), Log10($N_{res}$), ${\delta}$ and p values were examined. And in Log-linear+Shoulder+Tail model, the Log10($N_o$), Log10($N_{res}$), $k_{max}$, Sl values were calculated and examined.

• 한국환경과학회지
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• 제23권6호
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• pp.1165-1173
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• 2014

For the field application of dielectric barrier discharge plasma reactor in nutrient solution culture, a filtration-DBD (dielectric barrier discharge) plasma reactor was investigated for the Ralstonia solanacearum which causes bacterial wilt in aquiculture. The filtration-DBD plasma reactor system of this study was consisted of filter, plasma reactor, reservoir. The DBD plasma reactor consisted of a quartz dielectric tube, discharge electrode (inner) and ground electrode (outer). The experimental results showed that the inactivation of R. solanacearum with filter media type in filter reactor ranked in the following order: anthracite > fiber ball > sand > ceramic ball > quartz ceramic. In filtration + plasma process, disinfection effect with the voltage was found to small. In disinfection time of 120 minutes, residual R. solanacearum concentration was 1.17 log (15 CFU/mL). When the continuous disinfection time was 120 minute, disinfection effect was thought to keep the four days. In sporadic operation mode of 30 minutes disinfection - 24 hours break, residual R. solanacearum concentration after five days was 0.3 log (2 CFU/mL). It is considered that most of R. solanacearum has been inactivated substantially.