• Parasites, Hosts and Diseases
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• 제31권2호
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• pp.117-128
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• 1993

이 연구는 환자로부터 분리하여 무균 배양된 10개의 질트리코모나스 분리주에 대하여 병원성 여부를 판정하고 단백분해효소 관련 여부를 알아보고자 시도된 것이다. 질트리코모나스 분리주들은 마우스 피내 접종 실험을 통한 병원성 판정에서 약병원성 주, 중등도 병원성 주 및 강 병원성 주 등 3개 그룹으로 나눌 수 있었으며 중성 단백분해효소 및 산성 단백분해효소 활성도는 질트리코모나스 추출물 및 그 배양액에서 약 병원성 주에 비해 강 병원성 주의 활성도가 높게 나타나 피하농양 크기에 따른 병원성과 상기 단백분해효소의 비활성도(specific activi쇼) 사이에 상관관계가 있었음을 알 수 있었다(p < 0.05) 질트리코모나스 단백분해효소는 gelatin을 기질로 하는 SDS-PAGE 전기영동에서 RF치를 달리하는 5가지 분획대가 나타났으며 그 분획양상은 각 분리주 의 병원성에 따라 일정한 양상을 나타내었다. 그리고 여러가지 단백분해효소 억제제를 전기 영동 효소액에 처리했을 경우 antlpaln과 leupeptin 처리군에서는 분획이 전혀 나타나지 않았으며 EUTA 처리군에서는 대조군에 비해 그 활성이 약화된 분획이 관찰되었고, PMSF 처리군에서의 분획들은 대조군과 그 활성의 차이를 볼 수 없어 이들 단백 분해효소는 cystelne 단백분해효소로 추정되었다. 조직 세포에 대한 질트리코모나스 추출물의 세포독성은 병원성에 따라 차이가 있었고 추출물의 단백질 농도 $12.0{\;}\mu\textrm{g}/100{\mu}\ell$ 이상에서 세포 독성에 따른 병원성 구분이 용이하였다. 그리고 질트리코모나스 추출물에 단백분해효소 억제제를 처리한 결과 대조군에 비하여 세포 독성이 낮게 나타났으며, 특히 antipain 처리군에서는 조직 세포에 대한 세포 독성이 현저하게 낮았다. 이상의 결과로 보아 cysteine계로 추정되는 질트리코모나스의 단백분해효소는 특이한 전기영동 활성 분획상을 나타내었는 바 이들은 모두 충체의 병원성 및 세포 독성과 밀접한 관련이 있었다.

• Parasites, Hosts and Diseases
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• 제53권2호
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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.

• 대한수의사회지
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• 제8권2호
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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

• 미생물학회지
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• 제13권4호
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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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• 제29권4호
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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.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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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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• 제33권5호
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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.

• 한국어병학회지
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• 제12권2호
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• pp.107-113
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• 1999

능성어의 바이러스성 신경괴사증 바이러스(fish nodavirus)의 병원성을 능성어 및 다른 해산어류를 대상으로 인위감염법에 의해 조사한 결과, 능성어 바이러스성 신경괴사증 바이러스는 능성어에서는 소형어(27 g)부터 대형어(104 g)까지 제사를 일으켜 강한 병원성을 나타냈지만, 실험에 사용한 크기의 방어(537 g), 참돔(207 g), 돌돔(43 g), 넙치(41 g), 자주복(27 g) 및 조피볼락(94 g)에는 폐사를 일으키지 않아 병원성을 나타내지 않았다. 그리고 사육수온별 능성어에 대한 바이러스의 병원성은 수온 $15^{\circ}C$에서는 병원성을 나타내지 않았고, 수온 $20\sim28^{\circ}C$에서는 수온이 높을 수록 병원성을 강하게 나타냈다. 그리고 바이러스는 근육주사, 복강 주사 및 경구감염뿐만 아니라 침지감염과 혼합사육감염에 의해서도 쉽게 능성어에 감염이 되지만, 감염 후 생존한 능성어에 대해서는 바이러스를 재감염시켜도 폐사가 일어나지 않았다.

• The Plant Pathology Journal
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• 제26권1호
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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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• 제27권3호
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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.