• Parasites, Hosts and Diseases
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• v.31 no.2
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• pp.117-128
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• 1993

Ten axonic isolates of Trichomonns uaginolis were subcutaneously injected to the BALB/c mice in order to assess their pathogenicity by means of so-called "mouse assay" method. All the isolates revealed neutral and acid proteinase activities both in their Iysates and in culture media, but the specific activities of both proteinases in the severely pathogenic group were significantly higher than the mildly pathogenic group (p < 0.05). In the SDS-PAGE system in which the electrophoretic gels contained 0.4% gelatin as the substrate, five different handing patterns of trichomonal proteinases were detected, and the patterns were closely related with the pathogenicity of the isolates of T. vosinalis. All five bands might be regarded as cysteine proteinases group in the inhibitor assays. The cytotoxicity of the Iysates of T. vaginalis to the target Chinese hamster ovarian (CHO) cell line was also significantly different according to the pathogenicity of the isolates, and generally lower in the Iysates treated with cysteine proteinase inhibitors than in the control Iysates. In summarizing the results, it might be considered that the proteinases of T.vaginalis showing five electrophoretic banding patterns are closely related with the pathogenicity and cytotoxicity of the isolates of T. voginolis.

• Parasites, Hosts and Diseases
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• v.53 no.2
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• pp.155-162
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• 2015

Toxoplasma gondii is a protozoan parasite with a broad range of intermediate hosts. Chickens as important food-producing animals can also serve as intermediate hosts. To date, experimental studies on the pathogenicity of T. gondii in broiler chickens were rarely reported. The objective of the present study was to compare the pathogenicity of 5 different T. gondii strains (RH, CN, JS, CAT2, and CAT3) from various host species origin in 10-day-old chickens. Each group of chickens was infected intraperitoneally with $5{\times}10^8$, $1{\times}10^8$, $1{\times}10^7$, and $1{\times}10^6$ tachyzoites of the 5 strains, respectively. The negative control group was mockly inoculated with PBS alone. After infection, clinical symptoms and rectal temperatures of all the chickens were checked daily. Dead chickens during acute phage of the infection were checked for T. gondii tachyzoites by microscope, while living cases were checked for T. gondii infection at day 53 post-inoculation (PI) by PCR method. Histopathological sections were used to observe the pathological changes in the dead chickens and the living animals at day 53 PI. No significant differences were found in survival periods, histopathological findings, and clinical symptoms among the chickens infected with the RH, CN, CAT2, and CAT3 strains. Histopathological findings and clinical symptoms of the JS (chicken origin) group were similar to the others. However, average survival times of infected chickens of the JS group inoculated with $5{\times}10^8$ and $1{\times}10^8$ tachyzoites were 30.0 and 188.4 hr, respectively, significantly shorter than those of the other 4 mammalian isolates. Chickens exposed to $10^8$ of T. gondii tachyzoites and higher showed acute signs of toxoplasmosis, and the lesions were relatively more severe than those exposed to lower doses. The results indicated that the pathogenicity of JS strain was comparatively stronger to the chicken, and the pathogenicity was dose-dependent.

• Journal of the korean veterinary medical association
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• v.8 no.2
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• pp.3-16
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• 1964

For the purpose of researching the Erysipelothrix rhusiopathiae(E.r) organisms isolated from fish body surface and pathogenicity of domestic animals, I made practical isolation tests of the E. r. organisms for market fishes(Sea-fishes) at the market, and

• Korean Journal of Microbiology
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• v.13 no.4
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• pp.143-156
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• 1975

A rotting bacterium was isolated from decayed root of ginseng (Panax ginseng Meyer), cultured purely, and its pathogenicity was confirmed by reinoculation test. The strain causing ginseng root rot was identified as Pseudomonas fluoresens biotype II. The strain was somewhat different from P.marginalis and P.talaasii, considering the number of flagella, pathotype and ability of indole production. The strain did not exhibit pathogenicity to other plants tested, such as red kidney bean(Phasolus vulgaris L.), soy bean (Glycine max Merr.), cucumber (Cucumis sativus L.) lettuce (Lactuca sativa L.) and cowpea bean (Vigna sinensis Savi.).

• Mycobiology
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• v.29 no.4
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• pp.224-226
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• 2001

Inflorescence of Allium thunbergii was found to be severely infected with Fusarium sp. The flower was covered with the fungus and eventually failed to form seeds. The causal fungus was identified as F. proliferatum(Matsushima) Nirenberg based on the cultural and morphological characteristics. Pathogenicity of the fungus was proved by artificial inoculation onto the healthy plants. This is the first record of this disease from Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.131.1-131
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• 2003

This study reports the identification of species of Colletotrichum strains originating from red-pepper and Chinese matrimony vine in Cheongyang. Ninteen isolates of red-pepper and 26 Coiletotrichum isolates of Chinese matrimony vine were compared with 5 isolates of strawberry representing C. gloeosporioides, by use of morphological and cultural criteria. Twenty three isolates among 26 isolates from Chinese matrimony vine were identified as C. acutatum, characterized by the low growth rates and the low sensitivity to carbendazim and diethofencarb. Also, all the isolates of red-pepper were identified as C. acutatum, showing the same characteristics as those of Chinese matrimony vine. Three and five isolates from Chinese matrimony vine and strawberry, respectively, were identified as C. gloeosporioides, characterized by the high growth rates and the high seneitivity to carbendazim and diethofencarb. There were differences in colony color and pathogenicity between Chinese matrimony vine isolates and red-pepper isolates of C. autatum. The isolates of C. acutatum from Chinese matrimony vine producing orange colored colonies with abundant spores showed the strong pathogenicity to Chinese matrimony vine, although they could not infect fruits of red-pepper by the wound inoculation. However, red-pepper isolates of C. acutatum producing gray colonies showed the strong pathogenicity to Chinese matrimony vine as well as red-pepper. Furthermore, comparative study on PCR amplification of ITS regions of rDNA was carried out using a number of Colletotrichum isolates. A species-specific primer could be used for the identification of C. acutatum from red-pepper and Chinese matrimony vine.

• The Plant Pathology Journal
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• v.33 no.5
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• pp.458-466
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• 2017

Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial blight, is a major threat to rice productivity. Here, we performed RNA-Seq based transcriptomic analysis of Xoo transcripts isolated under in planta growth (on both susceptible and resistant hosts) and in vitro culture conditions. Our in planta extraction method resulted in successful enrichment of Xoo cells and provided RNA samples of high quality. A total of 4,619 differentially expressed genes were identified between in planta and in vitro growth conditions. The majority of the differentially expressed genes identified under in planta growth conditions were related to the nutrient transport, protease activity, stress tolerance, and pathogenicity. Among them, over 1,300 differentially expressed genes were determined to be secretory, including 184 putative type III effectors that may be involved in Xoo pathogenicity. Expression pattern of some of these identified genes were further validated by semi-quantitative RT-PCR. Taken together, these results provide a transcriptome overview of Xoo under in planta and in vitro growth conditions with a focus on its pathogenic processes, deepening our understanding of the behavior and pathogenicity of Xoo.

• Journal of fish pathology
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• v.12 no.2
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• pp.107-113
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• 1999

The pathogenicity of the fish nodavirus causing viral nervous necrosis (VNN) of sevenband grouper, Epinephelus septemfasciatus was examined in sevenband grouper and other marine fish by intramuscular injection. Sevenband groupers of 27~104 g in body weight were highly susceptible to the fish nodavirus, but yellowtail (537 g in body weight), red seabream (207 g), rock bream (43 g), flounder (41 g), tiger puffer (27 g) and rockfish (94 g) of the sizes used to this experiment were not. The pathogenicity of the viral agent to the sevenband grouper was high without regard to fish sizes at rearing water temperature over $20^{\circ}C$, but not at $15^{\circ}C$. Therefore, susceptibility of sevenband grouper to the viral agent causing VNN was thought to be water temperature-dependent rather than fish size (age-dependent). Compared to the infectivity of the viral agent to sevenband grouper with artificial infection methods, fish were successfully affected by intramuscular, intraperitoneal, oral, dipping and cohabitation administrations although there were slight differences in mortalities among infection methods. And survival sevenband grouper after infection with the fish nodavirus was resistant to the reinfection for a long time.

• The Plant Pathology Journal
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• v.26 no.1
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• pp.8-16
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• 2010

The phytopathogenic fungus Magnaporthe oryzae is a major limiting factor in rice production. To understand the genetic basis of M. oryzae pathogenic development, we previously analyzed a library of T-DNA insertional mutants of M. oryzae, and identified ATMT0879A1 as one of the pathogenicity-defective mutants. Molecular analyses and database searches revealed that a single TDNA insertion in ATMT0879A1 resulted in functional interference with an annotated gene, MGG00056, which encodes a short-chain dehydrogenase/reductase (SDR). The mutant and annotated gene were designated as $MoSDR1^{T-DNA}$ and MoSDR1, respectively. Like other SDR family members, MoSDR1 possesses both a cofactor-binding motif and a catalytic site. The expression pattern of MoSDR1 suggests that the gene is associated with pathogenicity and plays an important role in M. oryzae development. To understand the roles of MoSDR1, the deletion mutant ${\Delta}Mosdr1$ for the gene was obtained via homology-dependent gene replacement. As expected, ${\Delta}Mosdr1$ was nonpathogenic; moreover, the mutant displayed pleiotropic defects in conidiation, conidial germination, appressorium formation, penetration, and growth inside host tissues. These results suggest that MoSDR1 functions as a key metabolic enzyme in the regulation of development and pathogenicity in M. oryzae.

• The Plant Pathology Journal
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• v.27 no.3
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• pp.225-231
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• 2011

Previously, we identified the 20S proteasome ${\alpha}$-subunit of Magnaporthe oryzae (M. oryzae) induced during appressorium formation, and detected an increase in multiple protein ubiquitination during the early appressorium formation process (Kim et al., 2004). In this study, we further attempted to determine whether the proteasome is involved in the appressorium formation of M. oryzae both in vitro and in planta, using proteasome inhibitors. A significant increase in 20S proteasome during fungal germination and appressorium formation was observed using Western blot analysis with 20S proteasome antibody, demonstrating that proteasome-mediated protein degradation was involved in appressorium formation. Pharmacological analysis using proteasome inhibitors, MG-132, proteasome inhibitor I (PI) and proteasome inhibitor II (PII) revealed that germination and appressorium formation were delayed for 4 to 6 h on rice leaf wax-coated plates. Similarly, the treatment of proteasome inhibitors with fungal conidia on the rice leaf surface delayed appressorium formation and host infection processes as well. Additionally, fungal pathogenicity was strongly reduced at 4 days' postfungal infection. These data indicated that the fungal 20S proteasome might be involved in the pathogenicity of M. oryzae by the suppression of germination and appressorium formation.