• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.124-124
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• 2003

Citrus canker is very important disease in international trade of citrus. The disease was usually take place from late of June, and severe middle of July to middle of August, though disease occurrence was affected by environmental conditions. In pathogenicity test, three varieties, orange, lemon and kiyomi among 7 varieties, were succeptible, two varieties, satsuma mandarin and iwasachi, intermediate resistant. On the other hand, shiranuhi and yuzu were resistant relatively. The pathogen, Xanthomonas axonopodis pv. citri, grew well in PD broth adjusted to pH 7.0 at 26$^{\circ}C$. It's growth was best in medium containing group of monosaccharide as a carbon source and group of ammonium as a nitrogen source. Tow isolates were resistant to streptomycin among 11 isolates isolated from diseased leaves in field in Jeju-Do. The streptomycin sensitives isolate was controlled by in greenhouse test. On the other hand, the resistant and sensitive isolates were controlled by treatment with copper sulfate, the control value is 88.7％ and 90.6％, respectively.

• 한국식물병리학회지
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• 제14권2호
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• pp.177-183
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• 1998

A DNA fragment which is involved in tolassin production was cloned to obtain a molecular marker of Pseudomonas tolaasii, a casual agent of bacterial brown blotch disease of oyster mushroom (Pleurotus ostreatus). Tolaasin is a lipodepsipeptide toxin and known as a primary disease determinant of the P. tolaasii. It is responsible for formation of white line in agar when P. tolaasii were cultured against white line reacting organisms (WLROs). White line negative mutants (WL-) were generated by conjugation between rifampicin resistant strain of P. tolaasii and E. coli carrying suicidal plasmid pSUP2021 : : Tn5. The ability of tolaasin production of the WL- mutants was examined by hemolysis test, pathogenicity test, and high pressure liquid chromatography (HPLC) analysis of culture filtrate. All of the WL- mutants were lost the ability of tolaasin production (Tol-). Genomic library of the Tol- mutant was constructed in pLAFR3 and the cosmid clone containing Tn5 was selected. DNA fragment fro franking region of Tn5 was cloned from the plasmid and used as a probe in Southern blot. DNA-DNA hybridization with the probe to total DNA from group of bacteria ecologically similar to P. tolaasii including WLORs, fluorescent Pseudomonads isolated from oyster mushroom, P. agarici, P. gingeri, and some of other species of Psedomonas showed that some of the tested bacteria do not have any hybridized band and others have bands sowing RFLP. The cloned DNA fragment or its nucleotide sequence will be useful in detection and identification of the P. tolaasii.

• Journal of Microbiology and Biotechnology
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• 제28권12호
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• pp.2064-2070
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• 2018

Pseudomonas tolaasii 6264 is a representative strain that causes bacterial blotch disease on the cultivated oyster mushroom, Pleurotus ostreatus. Bacteriophages are able to sterilize the pathogenic P. tolaasii strains, and therefore, they can be applied in creating disease-free mushroom cultivation farms, through a method known as "phage therapy". For successful phage therapy, the characterization of phage-resistant strains is necessary, since they are frequently induced from the original pathogenic bacteria in the presence of phages. When 10 different phages were incubated with P. tolaasii 6264, their corresponding phage-resistant strains were obtained. In this study, changes in pathogenic, genetic, and biochemical characteristics as well as the acquired phage resistance of these strains were investigated. In the phylogenetic analyses, all phage-resistant strains were identical to the original parent strain based on the sequence comparison of 16S rRNA genes. When various phage-resistant strains were examined by three different methods, pitting test, white line test, and hemolytic activity, they were divided into three groups: strains showing all positive results in three tests, two positive in the first two tests, and all negative. Nevertheless, all phage-resistant strains showed that their pathogenic activities were reduced or completely lost.

• 식물병연구
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• 제23권4호
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• pp.367-371
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• 2017

2015년에 태안에서 장미의 가지 썩음 증상과 검은 포자체가 붙어 있는 새로운 증상이 관찰되었다. 이 증상의 원인을 찾기 위해 장미 가지의 썩음 증상에서 균사체를 분리하였다. 분리 균주의 병원성을 검정하였더니 건전한 장미 가지가 썩었으며 처음 발견했던 병징과 일치하였다. 형태학적 특성을 조사하고 분자생물학적 분석을 위하여 병원균을 $25^{\circ}C$에 7일간 배양하였다. 병원균의 균사 생장은 빠르며 균총의 색깔은 흰색에서 잿빛으로 변했다. 광학현미경으로 관찰한 분생포자는 회갈색의 타원모양에 격막이 하나 있으며 크기는 $20-31{\times}11-17{\mu}m$이다. 병원균의 ITS 영역, TEF와 TUB 유전자의 염기서열을 결합하여 근연종과 유연관계를 분석한 결과 Lasiodiplodia pseudotheobromae로 동정되었다. 이에 따라 장미에서 L. pseudotheobromae이 발생시키는 가지 썩음 증상을 장미 가지썩음병으로 명명하여 보고하고자 한다.

• 한국어병학회지
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• 제19권1호
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• pp.45-54
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• 2006

E. tarda의 독성 비교를 위하여 일반 TSB, iron-chelate인 2,2‘-dipyridyl 첨가 TSB 및 Fe 첨가 TSB의 세 가지 조건에서 E. tarda를 배양하였다. 독성시험의 결과는 iron-chelate 첨가 시험구의 E. tarda에서 가장 낮은 독성을 나타내었다. 그리고 각각의 OMPs와 IROMPs을 분리하여 SDS-PAGE로 항원성을 비교한 결과, iron-chelate 첨가 시험구의 E. tarda IROMPs에서 68, 73 kDa 크기의 분자들이 더 많이 발현된다는 것을 확인할 수 있었다. 두 가지 vaccine 투여구 중에서 2,2‘-dipyridyl 첨가 배지로 배양한 균체로 제작한 DP-FKC 항원 투여구가 응집 항체가가 더 높게 나타났다. 면역반응의 변화를 알기 위한 응집 항체가 조사에서는 FKC 항원과 DP-FKC 항원 투여구에서 모두 대조구보다 높은 값을 나타내었고, 3주 째에 최고치를 나타내었다. ELISPOT을 이용한 항체 생성 세포 수의 검출에서도 응집 항체가와 유사한 pattern을 나타내었는데, 두 가지 vaccine 투여구에서 2주 째에 가장 많은 항체 생성 세포 수를 나타내었다. 공격실험에서는 3주 째에 FKC 항원 투여구가 50%, DP-FKC 항원 투여구에서는 80%의 생존율을 나타내었다. 전체적으로 DP-FKC 항원 투여구의 생존율이 높게 나타났다. 이상의 결과로부터 넙치에 대한 E. tarda의 vaccine으로는 현재 연구되고 있는 FKC vaccine보다 철 결핍 조건에서 배양된 균체의 항원인 DP-FKC vaccine이 동일한 조건으로 사용하였을 때 더 나은 방어력을 가진다는 것을 알 수 있었다.

• 대한바이러스학회지
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• 제26권1호
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• pp.67-76
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• 1996

The methods that make Hantavirus grow consist of inoculation into the experimental animals and cultured cells. The cultured cells, such as Vero-E6 and A549 cells, have been usually used for isolation of the virus and the animals, such as mice and rats, are used for large scale preparation of the virus so far. Furthermore, the cell can be used to maintain the virus and assay the infectivity and the animals can be used for the experiment of viral pathogenicity and challenge for assessment of vaccine. Apodemus mice, the own natural host of the virus, has been used for challenge test of Hantaan virus. However it has been pointed out to difficult handling and breeding the animal in laboratory. Therefore, we attempted to establish a new animal model for challenge test at the time of isolation of Maaji virus which is a new hantavirus similar but distinct to Hantaan virus. In suckling hamster, the titer of Maaji virus and the lethality to mice of the virus were increased gradually in the titer and lethality through passage by intracerebral (IC) inoculation. We tried to re-adapt this brain virus to lung of weanling hamster. The brain passaged virus was inoculated into weanling hamster intramuscularly. Again, the titer of the virus in lung was also increased by continuous passage of this virus. This facts could regarded as adaptation to new environment in which the virus proliferates. To identity the virus passaged in hamster with Maaji virus, both of the virus passaged in hamster brain and lung were compared with Maaji virus (MAA-I) and Hantaan virus (HTN 76-118) by means of restriction fragment length polymorphism (RFLP) and slingle strand conformation polymophism (SSCP). As a result, we conclude that Maaji virus could be adapted successfully to weanling hamster through this passage strategy. Utilizing this adapted Maaji virus strain, hamster model is able to be used for challenge test in hantaviral vaccinology and further experiments utilizing hamster system as a rather available and convenient lab animal are expected.

• 대한수의학회지
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• 제32권3호
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• pp.369-376
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• 1992

This paper dealt with plasmid DNA profile in 98 Salmonella(S) isolated from pigs and cattle sources in Taegu, Gyeongbook and Gyeongnam during the period from 1984 to 1987. Also we were studied for restriction enzyme analysis of the plasmid DNA, and mouse infection, Sereny test and normal setum resistance test in guinea pig for S typhimurium and S enteritidis harbored or cured 60 megadalton(Md) plasmid and 36 Md plasmid, respectively. Of the 13 Salmonella isolated from cattle, 7 Salmonella harbored one or more plasmids and molecular sizes of the large plasmids were 60 Md for S typhimurium and 36 Md for S enteritidis. Of the 85 Salmonella isolated from pigs, 47 Salmonella were confirmed as being one or more plasmids, and all the S typimurium stains harbored 60 Md plasmid. In enzyme digestion with 8 types of restriction endonuclease for 60 Md plasmid DNA of S typhimurium, cleavage patterns were varied to enzymes, and the DNA was segmented into 4 to 15 fragments. In restriction enzyme analysis of 36 Md plasmid DNA obtained from four strains of S. enteritidis, the DNA showed the same cleavage patterns obtained with Eco RI, Hind III and Bam H I, and was segmented into 3 to 5 fragments. In virulence for mice by measuring the 50% lethal dose ($LD_{50}$), the $LD_{50}$ values obtained for 60 Md virulence-associated plasmid harbored strains of S typhimurium and 36 Md virulence-associated plasmid of S enteritidis were up to $10^4$-fold lower than the values obtained for the plasmid-cured strains of the same serotype. Only the plasmid harbored strains were resistant to the bactericidal activity of 90% guinea pig serum, and only they gave positive responses in sereny test. We suggested that their plasmid DNA might be associated with virulence for mice.

• 한국어병학회지
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• 제36권2호
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• pp.263-275
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• 2023

첨연어(Oncorhynchus keta)는 한국에서 회귀하는 연어로 종 보존을 위해 경상북도 울진군에 위치한 수산자원공단에서 해수 순치하며 종묘 생산하였다. 그러나, 사육 중이던 첨연어 치어에서 세균성 질병에 감염된 증상을 보이며 폐사하였다. 따라서, 본 연구에서는 2021년 10월경에 사육환경에 따라 구분된 첨연어로부터 원인체를 규명하고자 세균을 분리하였다. 분리된 세균은 16S rDNA, rpoD (RNA polymerase sigma factor σ⁷⁰) 및 vapA (A-layer)의 염기서열을 기반으로 유전학적으로 동정하고, 추가로 염분에 따른 성장, 생화학적 특성 분석, 항생제 감수성 및 병원성 인자를 분석하여 균주를 특성화하였다. 그 결과, 분리된 4개의 균주는 모두 Aeromonas salmonicida subsp. salmonicida 아종으로 동정하였다. 또한, 분리된 균주는 염분의 농도가 증가할수록 배지에서 성장이 감소하였다. 생화학적 특성 분석에서 분리된 4개 균주는 용혈성이 확인되지 않았고, 모두 같은 생화학적인 성상을 나타냈다. 항생제 감수성 분석에서는 oxolinic acid, flumequine 그리고 florfenicol에 대한 항생제에서 40~44 mm 억제대를 형성하였다. 병원성 인자의 발현 분석은 mRNA 수준에서 RT-PCR로 확인되었으며, 4개 균주는 모두 A. salmonicida의 병원성에 크게 기여한다고 잘 알려진 outer membrane ring of T3SS (ascV), inner membrane ring of T3SS (ascC), vapA, enterotoxin (act) 및 lipase (lip) 유전자가 발현되었다. 이 연구에서 분리된 A. salmonicida subsp. salmonicida의 특성 분석은 해수에 순치된 첨연어에서 발병하는 절창병을 예방하기 위한 기초자료로 활용될 수 있을 것이다.

• 대한수의학회지
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• 제21권2호
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• pp.93-97
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• 1981

It has long been believed for the presence of infectious coryza affecting serious economic loss in domestic poultry industry. However, the etiologic agent has not been isolated until quite recently. From 1979, several strains of Haemophilus-like organism were isolated from chickens with symptoms similar to infectious coryza, and their colonial morphology, growth requirement, biochemical properties and pathogenicity were assessed. In addition, serological properties of the isolates by cross hemagglutination inhibition test was also investigated. The results indicated that all the isolates were identified as Haemophilus gallinarum which had similar characteristics to the reference strains.

• Mycobiology
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• 제45권1호
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• pp.39-43
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• 2017

Leaf spot disease on black chokeberry (Aronia melanocarpa) was observed at several locations in Korea during 2014-2015. Leaf spots were distinct, scattered over the leaf surface and along the leaf border, subcircular to irregular and brown surrounded by a distinct dark color, and were expanded and coalesced into irregularly shaped lesions. Severely infected leaves became dry and fell off eventually. The causative agent was identified as Pseudocercospora pyricola. Morphological observations and phylogenetic analyses of multiple genes, including internal transcribed spacer, translation elongation factor 1-alpha, actin, and the large subunit ribosomal DNA were conducted. The pathogenicity test was conducted twice yielding similar results, fulfilling Koch's postulates. To our knowledge, this is the first report on P. pyricola infection of A. melanocarpa globally.