• KSBB Journal
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• v.23 no.3
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• pp.219-225
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• 2008

For the production of an antifungal compound, one strain (I-8) was selected from approximately 400 strains isolated from various soil samples. The optimum carbon source, nitrogen source and pH culture conditions for the production of the antifungal compound were investigated. ISP No. 2 medium (yeast extract 0.4%, malt extract 1% and dextrose 0.4%, at pH 8) was determined to be the optimum medium. Strain I-8 showed broad antifungal activity against the plant pathogenic fungi tested, including Sclerotinia sclerotiorum KACC 41065, as well as cellulase and chitinase activities in an agar plate assay. The extraction of antifungal compounds was performed using ethyl ether and ethyl acetate. In a culture broth of strain I-8, the ethyl acetate extract exhibited effective growth inhibition against 14 of the 20 phytopathogenic fungi tested. By mixing the ethyl acetate extract from I-8 with the ethyl ether extract from the fungus 13-16, which shows specific antifungal activity against Colletotrichum orbiculare KACC 40808, the antifungal activity of I-8 against phytopathogenic fungi was confirmed to be slightly increased. Strain I-8 showed strong growth inhibition against 16 phytopathogenic strains in agar plate tests.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.63-72
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• 1995

This study was carried out to isolate the soil bacteria degrading herbicide napropamide [N,N-diethyl-2-(1-naphthoxy)-propionamide] from the clayey loam soil tested and to clarify the characteristics of the napropamide-degrading bacteria. Twenty strains of the gram-positive and the gram-negative bacteria were isolated and identified from the clayey loam soil tested. Most of them were vigorously proliferated at 100ppm of napropamide and two strains of Staphylococcus spp., Corynebacterium spp. II and Other spp. II were very tolerated to napropamide even at the concentration of 1500ppm. Staphylococcus spp. II and Actinobacillus spp. II of the isolated bacteria degraded more than 20% of the treated napropamide. These two strains could not utilize napropamide as sole nitrogen sources, but could use this compound as sole carbon sources. Napropamide was rapidly decomposed by Staphylococcus spp. II at one-time application and at three-time application of napropamide, but wasn't at two-time application of napropamide.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.345-352
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• 1989

The immunochemical property of lectin in soybean and the presence of lectin in seeds of six soybean cultivars were investigated by immunochemical methods. All seeds of six soybean cultivars formed one precipitin line against the soybean lectin antibody and showed immunochemically homologous precipitin pattern among the cultivars in immunodouble diffusion test. Four antigenic components in soybean lectin were detected by the crossed imuno-electrophoresis of a soybean seed antigen against the soybean lectin antibody. Cultivar, Jangyeop-kong contained the highest amount of lectin and the next were Kwangkyo, Hwangkeumkong, Baegunkong, and Jangbaegkong or Paldal-kong in order of lectin content. The lectin purified from the seeds of six soybean cultivars agglutinated rabbit erythrocytes, but did not agglutinate the fungal spores which were Fusarium sp., Alternaria sp., Cuvalaria sp., and Colletotrichum sp. isolated from the infected seeds or leaves of soybean.

• The Korean Journal of Mycology
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• v.48 no.4
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• pp.369-379
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• 2020

Black mold was frequently observed on tomatoes grown in a greenhouse in Suwon, Korea in July 2018. The incidence of the disease was 5.0-25.0% (average 12.3%) and 2.0-7.0% (average 3.7%) in the context of tomato and cherry tomato fruits, respectively. Sixteen single-spore isolates of Alternaria sp. were obtained from the diseased fruits and investigated for their morphological characteristics. Among the isolates, eight were used for sequencing analysis. All of the isolates were identified as Alternaria alternata based on their morphological and molecular characteristics. The pathogenicity of four isolates of A. alternata was investigated using three varieties each of tomato and cherry tomato via artificial inoculation. All of the isolates induced black mold symptoms on the inoculated tomato fruits. Notably, the symptoms were similar to those observed in the greenhouse. However, the pathogenicity tests revealed that different tomato varieties presented distinct patterns of susceptibility to the isolates. This is the first report of A. alternata causing black mold on tomato fruits in Korea.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.217-222
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• 1987

Pathogenicity of nine Rhizoctonia solani isolates of different anastomosis groups (AG) on seed and hypocotyls of red pepper, cucumber, Chinese cabbage and radish varied considerably from nonvirulent to highly virulent. Rhizoctonia solani AG 1 was highly virulent on the above four plant species. AG 2 type 1 was highly virulent on radish and Chinese cabbage, moderately virulent on red pepper, and AG 2 type 2 was avirulent or weakly virulent except red pepper. R. solani AG 5 was moderately virulent on hosts tested. In general, virulence of the R. solani isolates to a given host varied among anastomosis groups, but not within anastomosis groups. Anastomosis groups lacked host specificity. The pathogenicity was stronger in steam-sterilized soil than in non-sterilized field soil, if the inoculated plants were closely related with orginal host from which the pathogen was isolated. On the other hand, pathogen was more virulent in non-sterilized field soil than in steam-sterilized soil, if the inoculated ones were not closely related. Generally, contrary to other soil-brone plant pathogenic fungi, Rhizoctonia isolates tended to be more virulent in non-sterilized field soil than in the same soil which had been steamed. A potential danger of building up propagules of R. solani in southern horticultural area are discussed in terms of cropping system.

• The Korean Journal of Mycology
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• v.31 no.2
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• pp.103-113
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• 2003

Twenty five isolates of Alternaria were obtained from various solanaceous crops in Korea. For all isolates, morphological characteristics of the conidia were determined and compared with those of representative isolates of A. solani and A. tomatophila. A selection of the isolates and the representative Alternaria isolates were evaluated for Pathogenicity to potato, tomato, egg plant and red pepper. Molecular characteristics of 17 isolates of Alternaria inculding the representative isolates were determined using sequence analysis of IRS rDNA and histone H3 gene, and URP-PCR analysis. Based on morphological characteristics, the isolates from the solanaceous crops were grouped as identical or very similar to either A. tomatophila (ATO), A. solani (ASO), and unidentified Alternaria sp. (ASP). Isolates of ASO were moderately pathogenic to all the solanaceous crops tested, but ATO isolates were highly pathogenic to tomato and the ASP isolate was pathogenic only to potato. Among the molecular markers used in this study, the URP-PCR analysis was found to be appropriate for taxonomic resolution of these species. Based on the conidial morphology, pathogenicity test and molecular characteristics, A. tomatophila (early blight of tomato) could be distinguished from A. solani (early blight of potato), and the Alternaria sp. (ASP) from potato, which was closely related to ASO in conidial morphology, was considered as a new species.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.2
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• pp.104-108
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• 2016

The objective of this study was to determine how feeding forage and concentrate separately (SF) or as a total mixed ration (TMR) affects enteric methane production of cattle. Six Holstein steers ($203{\pm}22.5kg$) were used in a $2{\times}3$ changeover design experiment. Experimental diets (TMR and SF) consisted of compound feed, timothy hay and soybean curd residue in a ratio of 40:48:12, respectively, and diets were fed at 10% of metabolic body weight, on an as-fed basis. There were no differences in dry matter intake and enteric methane production (g/d) between SF and TMR but the methane conversion rate (methane energy/GE intake) of TMR was significantly higher (p=0.05) than that of SF. The mean methane emission factor (kg/head/year) and conversion rate of the two treatments were 21.4 and 0.05, respectively. There was a strong relationship between metabolic body weight and enteric methane production (p<0.001). At the present time, further studies may be necessary in order to establish the effects of TMR and SF on enteric methane production.

• 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.

• Journal of Life Science
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• v.10 no.3
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• pp.262-272
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• 2000

As a part of investigation for basic epidemiology of diarrheogenic disease, we attempted isolation of Escherichia coli from patients with diarrhea. Seven hundred and twenty-one strains of E. coli were isolated from 1,239 patients with diarrhea. Seasonal distribution of patient with diarrhea was shown the most high at August (18.2%). Age group distribution of patient was shown the most high at children (54.6%, 2 to 10 years old). The serotypes of 721 E. coli isolates were in order of serotype O44 (16.8%), O153 (8.6%), O1 (7.5%), O166(5.7%), O8 and O86a (4.7%), and O125 (4.6%). The supernates cultured 36 strains among 721 E. coli isolates were indicated cytotoxicity against monolayered Vero cells. All of the isolates were susceptible to amikacin. The isolates were resistant in order of novobiocin (99.0%), moxalactam (97.1%), carbenicillin (96.1%), tetracycline (90.4%), ampicillin (85.9%), gentamicin (84.0%), streptomycin (78.4%), cephalothin (46.6%) and polymyxin B (4.2%). In the antibiotic resistant patterns, 125 kinds of multiple resistance patterns of E. coli isolates were detected. The highest resistant pattern was ampicillin-carbenicillin-chloramphenicol-cephalothin-erythro-mycin- gentamicin-moxalactam-novobiocin-penicillin G-streptomycin-tobramycin-tetracycline-tri methoprim type (24.3%).

• Journal of the Korea Concrete Institute
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• v.13 no.4
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• pp.336-345
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• 2001

The construction of underwater structures has been increased, but underwater concrete hassome problems of quality deterioration and contamination around in-situ of civil and architecture; therefore, new materials and methods for them are demanded. In this paper in-situ application of underwater antiwashout concrete which is manufactured for trio purpose of not only decreasing suspended solids and the heat of hydration but also increasing long term strength was studied. In the case of mock-up test(Ⅰ), when underwater antiwashout concrete, whose slump flow was 58 cm, was placed in the mock-up test at a speed of 24 ㎥/hr, it took about a minute to flow to the side wall, and the surface was maintained at horizontal level. In this case, compressive strength of the core specimens in each section was higher than the standard design compressive strength of 240 kgf/㎠. In the case of mock-up test(II), pH value and suspended solids of high strength underwater antiwashout concrete were 10.0∼11.0 and 51 mg/ℓ at 30 minutes later, initial and final setting time were about 30, 37 hr, and the slump flow of that was 53$\pm$2 cm. In the placement at a speed of 27 ㎥/hr, there was no large difference in flowing velocity, with or without reinforcement and flowing slope was maintained at horizontal level. In this case, compressive strength and elastic modulus of the core specimens somewhat decreased as flowing distance was far : however, those of central area showed the highest value.