• Research in Plant Disease
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• v.29 no.2
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• pp.118-129
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• 2023

Fusarium sambucinum species complex (FSAMSC) is an important taxonomic group, causing severe plant diseases. Many studies were carried out on FSAMSC plant diseases in Korea, but only 2 species (F. graminearum, F. sambucinum) from 14 host plants were registered in the List of Plant Disease in Korea. To clarify FSAMSC diversity and their pathogenecity, we examined FSAMSC isolates preserved in the Korean Agricultural Culture Collection. Fifty-seven strains were reidentifed as 7 species (F. asiaticum, F. graminearum, F. vorosii, F. meridionale, F. boothii, F. kyushuense, F. armeniacum) based on multi-locus sequence typing analysis. According to previous reports and result of this study, 5 species (F. asiaticum, F. graminearum, F. vorosii, F. armeniacum, F. sambucinum) were pathogenic on 24 host plants in FSAMSC, while the pathogenicity of 3 species (F. meridionale, F. boothii, F. kyushuense) were not clear.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.129.1-129
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• 2003

A destructive stem rot of strawberry (cv. Akihime) occurred sporadically in farmers' fields around Daegok-Myeon, Jinju City, Gyeongnam province in Korea. The infected plants showed stem and crown rot, sometimes whole plant blighted. White mycelia spread over stems of infected clones and sclerotia formed on the old lesions near to soil surface. The fungus formed white colony on PDA and showed maximum mycelial growth and scleotial formation around 30$^{\circ}C$. The fungus usually have many narrow mycelial strands in the aerial mycelium and the width were 4.0∼10.0$\mu\textrm{m}$. The typical clamp connections were formed on the mycelium. The shape of sclerotia was globoid and 1.0∼2.8 mm in size. The fungus was isolated repeatedly from the infected tissues and identified as Sclerotium rolfsii. The fungus was inoculated to strawberry and confirmed its pathogenecity This is the first report on the stem rot of strawberry caused by Scierotium rolfsii in Korea.

• The Journal of the Korean Society for Microbiology
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• v.34 no.5
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• pp.461-470
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• 1999

Growth under conditions of iron-restriction and the production of siderophore was examined in Vibrio mimicus ATCC 33653. This strain grew and multiplied in the presence of the high-affinity iron chelators ethylenediamine-di (o-hydroxyphenylacetic acid). Chrome azurol S (CAS) agar and solution were used to detect the production of siderophore under these condition. Siderophore could be detected in the iron-restricted culture supernatants. The siderophore was extracted from iron-restricted culture supernatants by phenol-chloroform-ether method and purified by Dowex ion-exchange and Sephadex G-25 gel filtracton chromatography. The purified siderophore was confirmed by paper chromatography and HPLC. The Purified siderophore enhanced the growth of V. mimicus when the bacterium was grown in iron limited medium. Injection of both the siderohore and the bacteria to mice resulted in more rapid death than that of the only bacteria. However, the siderophore did not show lethality to mice and any toxicity to cell line like HeLa and U937.

• The Journal of the Korean Society for Microbiology
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• v.21 no.3
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• pp.331-336
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• 1986

A microbiological study for the isolation and characterization of Leptospira interrogans was performed in an attempt to define the characteristics of Leptospirosis in Korea. The results are summerised as follows. Thirty-five cultures were isolated from 11 patients with leptospirosis and 24 wild rodents captured in Paju area. The isolation rate of Leptospira from wild rodents reached 23.1%. All 35 cultures were identified as Leptospira interrogans by their characteristic morphology and motility in dark field microscopy, pathogenecity in Guinea pig and sensitivity to 8-Azaguanine. Cultures formed diffuse subsurface colonies with hazy margin and were catalase, peroxidase and oxdase positive. The fifty percent lethal dose of isolate HM 4 in Guinea pig was $8.9{\times}10^4$ org. Mouse passage method was sucecssfully applied in maintenance of fresh isolates without any loss of their original virulency.

• Mycobiology
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• v.29 no.1
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• pp.58-60
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• 2001

A destructive stem rot of wild aster(Aster koraiensis) occurred sporadically some farmers' fields in Guman-myon, Kosonggun, Kyongsangnam-do in 2000. One of the most severely infected field in Kosong showed 28.6 percent of infection rate. The fungus also caused stem or crown rot and systemic wilt or blight of the plants. White mycelium spread over stems and petioles of infected plants and sclerotia formed on the old lesions and near the soil surface. The fungus showed maximum mycelial growth around $30^{\circ}C$ and did not grow under $5^{\circ}C$ and over $45^{\circ}C$ and mycelial width were $4.3{\sim}10.2{\mu}m$. Colony was white, usually many narrow mycelial stand in the aerial mycelium and formed clamp connection. Numerous sclerotia were formed on PDA at $30^{\circ}C$. The shape sclerotia were globoid and $0.8{\sim}3.0{\times}0.9{\sim}3.4$ mm in size. The fungus was isolated repeatedly from the infected tissues and confirmed its pathogenecity to wild aster and identified as Sclerotium rolfsii. This is the first report on the stem rot of wild aster caused by S. rolfsii in Korea.

• Korean Journal of Medicinal Crop Science
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• v.21 no.1
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• pp.27-31
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• 2013

This study was conducted to isolate and identify the fungal pathogen causing seedling rot of Lithospermum erythrorhizon Siebold & Zuccarini, and to know the optimum growing temperature for decreasing seedling rot of Lithospermum erythrorhizon. On the basis of morphological characteristics, EF-1a sequence analysis, and pathogenecity to host plant, the fungi isolated from seedling rot and seeds of Lithospermum erythrorhizon were identified as Fusarium fujikuroi, indicating that disease causing fungus is seed-borne pathogen. Optimum temperature for germination of seeds of Lithospermum erythrorhizon was $15{\sim}20^{\circ}C$, but pathogenicity of Fusarium fujikuroi was shown more readily at $25{\sim}30^{\circ}C$. These results suggested that seedling culture of Lithospermum erythrorhizon between $15^{\circ}C$ and $20^{\circ}C$ might reduce seedling rot of Lithospermum erythrorhizon caused by seed-borne pathogen Fusarium fujikuroi.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.138-144
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• 2000

This study was carried out to investigate the pathogenicity of Korea N caninum isolates, KBA-1 and KBA-2 on SCID mouse following 3 different routes of infection. NC-1 was served as reference isolate. The pathogenecity was evaluated by progression of clinical signs, histopathology and immunohistochemistry. Pathogenicity of KBA-2 appears to be stronger than that of KBA-1 but weaker than that of NC-1. Progress of clinical signs and lesion distribution and pattern of each isolates were similar when the isolates were infected either subcatareously or intraperitoneally. However, oral inoculation of tachyzoites failed to induce the infection.

• Korean Journal of Veterinary Research
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• v.33 no.2
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• pp.301-308
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• 1993

Three or 7day old piglets were infected experimentally with different encephalomyocarditis virus isolates to detect the viral antigen by the immunoperoxidase technique and to observe strain difference in their pathogenecity in newborn pigs by comparing clinical signs and pathologic lesions. Clinical signs of the infected pigs were different depending on the virus strain, pig age and infection route. Encephalomyocarditis virus(EMCV) NVSL-PR isolate was more pathogenic than MN-25 and MN-30 isolate. Three day old piglets showed more severe illness than 7 day old piglets. Predominant clinical signs were sudden death without noticeable clinical signs and dyspnea manifested as heavy abdominal breathing. Contact-infection from infected piglets to controls was observed in the oro-nasally infected group but not the intramuscular group. Common necropsy findings of dead piglets in both age groups infected with MN-25 and NVSL-PR were accumulation of excessive fluid in the body cavities and mild to diffuse necrotic areas observed in the hearts and occasionally in the livers. Microscopically, myocarditis with inflammatory cell infiltration, necrosis of the myocardial muscle fibers and occasional mineralization were observed along with interstitial pneumonia and centrolobular necrosis in the liver. Using an immunoperoxidase technique, viral antigen was detected in myocardial muscle fibers of piglets infected with EMCV.

• Mycobiology
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• v.30 no.2
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• pp.102-104
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• 2002

In July 2001, a destructive stem rot of tatarian aster(Aster taturicus) was occurred sporadically in exhibition farm of Gyeongsangnam-do Agricultural Research and Extension Services, in Hamyang, Korea. The fungus also caused collar and crown rot and systemic wilt or blight of whole plant. White mycelium spread over stems and petioles of infected plants and sclerotia formed on the old lesions and near the soil surface. The fungus showed maximum mycelial growth was obtained around $30^{\circ}C$ but did not grow below $5^{\circ}C$ or above $45^{\circ}C$. The mycelial width ranges $4.2{\sim}10.4{\mu}m$. and the color is white, usually many narrow mycelial stand grow in the aerial mycelium and formed clamp connection. Numerous sclerotia were formed in artificial media like PDA at $30^{\circ}C$. The shape of sclerotia were sphere and $1.0{\sim}3.2{\mu}m$ in diameter. The fungus was isolated repeatedly from the infected, tissues and confirmed its pathogenecity to aster and identified as Sclerotium rolfsii. This is the first report that Sclerotium rolfsii causes stem rot of tatarian aster in Korea.

• Korean Journal of Microbiology
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• v.9 no.2
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• pp.61-68
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• 1971

Borrelina virus was inoculated into Hyphantrea cunea DRURY in the labolatory and in the field. The pathogenecity of Borrelina virus upon Bompyx mori L. and Dendrolinus spectabilis BUTLER, too, was examined with following results. 1) $10^8$/ml, $10^7$/ ml, $10^6$/ml concentration of nuclear-polyhedrosis virus was inoculated into the larvae of H.cunea at various ages. The corrected mortality of the larvae were 97.4%, 95.2%, 94.7% in the 3rd instar, and 88.6%, 73.6%, 62.5% in the 6th instar, respectively, with three different concentration of NPV. 2) The symptom of disease of the larvae appeared on 4days after inoculation and most of the larvae were dead within 18 days. 3) The youngest larvae treated with the highest concentration of NPV showed the highest mortality. With older larvae and lower concentriton treated, it appeared that the time needed for death grew longer, marking slower death curve. 4) When we sprayed NPV of $10^6$/ml concentration to H. cunea in the field, the mortality was 94.8% in the first year, 84.6% in the second year and 78.3% in third year. By this, we could admit the continuous effects of the pathogens for several years. 5) About the larvae of B. mori of 3rd and 5th instar and D.spectabilis of 3rd instar inoculated with $10^8$/ml concentration of inoclum, we could not see any pathogenic effects.