• 대한의생명과학회지
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• 제18권1호
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• pp.79-82
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• 2012

Acinetobacter infections are of great concern in clinical settings because of multi-drug resistance (MDR) and high mortality of the infected patients. The MDR Acinetobacter baumannii has emerged as a significant infectious agent in hospitals worldwide. The purpose of this study was to determine for molecular characterization of MDR A. baumannii clinical isolates obtained from the Wonju Christian Hospital in Gangwon province of Korea. A total of seventy nonduplicate A. baumannii isolates were collected from the Wonju Christian Hospital in Korea from March to April in 2011. All of the MDR A. baumannii isolates were encoded by $bla_{OXA-23-like}$ gene and all isolates with the $bla_{OXA-23-like}$ gene had the upstream element ISAba1 to promote increased gene expression and subsequent resistance to carbapenem. 16S rRNA methylase gene (armA) was detected in 44 clinical isolates which were resistant to amikacin, and phosphotransferase genes encoding aac(3)-Ia and aac(6')-Ib were the most prevalent. A combination of 16S rRNA methylase and aminoglycoside-modifying enzyme genes (armA, aac(3)-Ia, aac(6')-Ib, and aph(3')-Ia) were found in 31 isolates. The sequencing results for the quinolone resistance-determining region (QRDR) of gyrA and parC revealed the presence of Ser (TCA) 83 Leu (TTA) and Ser (TCG) 80 Leu (TTG) substitutions in the respective enzymes for all MDR. Molecular typing for MDR A. baumannii could be helpful in confirming the identification of a common source or cross-contamination. This is an important step in enabling epidemiological tracing of these strains.

• 한국어병학회지
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• 제35권2호
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• pp.215-223
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• 2022

Disease including parasite, bacteria and virus cause serious mortality to salmonid fish in the aquaculture. In this study, we investigated the current disease status of the rainbow trout (Oncorhynchus mykiss) and coho salmon (Oncorhynchus kisutch) in Yanayang, Pyeongchang, Jeongseon and Yeongwol of Gangwon province in 2021 and performed molecular characterization of those pathogen. For parasites, Ichthyophthirius multifiliis was observed at 2 farms. For bacteria, we identified Aeromonas sobria from kidney of rainbow trout using phylogenetic analysis of gyrB gene. A. salmonicida were isolated from necrosis site of gill cover and fin in coho salmon and necrotic lesion of fin in rainbow trout. Phylogenetic analysis using vap gene indicated that A. salmonicida isolated in this study were clustered with previously reported A. salmonicida subsp. salmonicida isolates. For virus, JRt-Nagano type of infectious haematopoietic necrosis virus was detected in rainbow trout, but infectious pancreatic necrosis virus and Oncorhynchus masou virus were not detected. These results provide useful information for the prevention of disease spread and transmission when cultivating new species such as Atlantic salmon in Korea.

• 식물병연구
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• 제10권4호
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• pp.331-336
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• 2004

결구상추에 심각한 피해를 일으키는 균핵병의 생물학적 방제를 위한 기초연구로서 균핵병원균 S. sclerotioum YR-1 대한 우수 길항세균을 선발하고 동정하였다. 건전 결구상추에서 분리한 세균들 중 균핵병원균의 균사생육저지 효과가 큰 10 균주를 길항세균으로 1차 선발하고 이들 일차 길항세균에 의한 방제효과를 생육실내 포트검정한 결과, A-2, A-7 및 RH-4 균주의 방제가가 각각 73.0%, 85.0%, 80.0%이었으며, 이 중 가장 높은 방제가를 보인 A-7 균주를 우수 길항균으로 최종선발하였다. A-7 균주의 생화학적 특성 및 16S rDNA와 gyrA 염기서열을 분석한 결과 Bacillus amyloliquefaciens로 동정되었으며, B. amyloliquefaciens A-7으로 명명하였다.

• 식물병연구
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• 제22권3호
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• pp.158-167
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• 2016

육묘장과 재배포장의 애호박에서 새롭게 발생한 병원균의 특성을 분석하여 동정하였다. 병징은 잎에 수침상의 병반과 강한 노란색의 둘레무리를 가진 점무늬, 꽃에서 갈색 병반, 열매에 노란색의 점무늬였다. 잎의 점무늬로부터 분리된 세균은 박과작물 8개의 식물체, 흑종호박, 애호박, 쥬키니호박, 풋호박, 참박, 참외, 멜론, 오이에 병원성이 있었지만 수박과 밤호박에서는 병을 일으키지 못했다. 분리세균은 다발모를 가진 막대형으로 그람음성이며 King's B 배지에서 형광성이었으며, LOPAT 1a 그룹에 속했다. 그들의 Biolog 기질이용성은 Biolog database의 P. syringae pv. syringae 이용성과 유사하였다. 16S rRNA 유전자 염기서열을 이용한 계통수와 4개의 항존유전자(gapA, gltA, gyrB, rpoD)의 염기서열과 PAMDB에 있는 P. syringae균주들의 염기서열을 이용한 MLST는 애호박 분리균주들이 P. syringae pv. syringae 균주들과 동일한 그룹(clade)으로 그룹화되었고, MLST 계통수에서 애호박 분리균주들의 그룹(clade)은 genomospecies 1에 속하였다. 표현형적, 유전적 특성은 애호박 분리균이 P. syringae pv. syringae임을 제시하였다.

• Journal of Microbiology and Biotechnology
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• 제31권9호
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• pp.1231-1240
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• 2021

Members of the genus Bacillus are known to play an important role in promoting plant growth and protecting plants against phytopathogenic microorganisms. In this study, 21 isolates of Bacillus spp. were obtained from the root micro-ecosystem of Suaeda glauca. Analysis of the 16S rRNA genes indicated that the isolates belong to the species Bacillus amyloliquefaciens, Bacillus velezensis, Bacillus subtilis, Bacillus pumilus, Bacillus aryabhattai and Brevibacterium frigoritolerans. One of the interesting findings of this study is that the four strains B1, B5, B16 and B21 are dominant in rhizosphere soil. Based on gyrA, gyrB, and rpoB gene analyses, B1, B5, and B21 were identified as B. amyloliquefaciens and B16 was identified as B. velezensis. Estimation of antifungal activity showed that the isolate B1 had a significant inhibitory effect on Fusarium verticillioides, B5 and B16 on Colletotrichum capsici (syd.) Butl, and B21 on Rhizoctonia cerealis van der Hoeven. The four strains grew well in medium with 1-10% NaCl, a pH value of 5-8, and promoted the growth of Arabidopsis thaliana. Our results indicate that these strains may be promising agents for the biocontrol and promotion of plant growth and further study of the relevant bacteria will provide a useful reference for the development of microbial resources.

• 농약과학회지
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• 제20권3호
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• pp.189-196
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• 2016

바실러스는 토양 및 반추동물의 소화기관과 같은 다양한 곳에서 분리되고 있으며, 작물의 생육 촉진과 병방제를 위한 미생물 재제로서 널리 사용되고 있다. 바실러스 GH1-13 균주는 전남 완도의 간척지 논에서 분리되었으며, 16S rRNA 유전자와 gyrB 유전자를 이용하여 계통유전학적으로 분석한 결과 Bacillus velezensis인 것으로 동정되었다. GH1-13 균주의 특성을 분석한 결과 생육촉진에 관련된 IAA를 생성할 뿐 아니라 벼 뿌리의 생육을 촉진하는 것을 확인하였다. 또한 벼의 주요 병원균의 생육을 억제할 뿐 아니라 작물의 병원균인 다양한 곰팡이의 생육을 저해하였다. 더불어 식물병원 진균 및 세균의 생육 억제와 밀접하게 관련된 것으로 판단되는 bacillomycin, bacilycin, fengycin, iturin, surfactin을 생성하는 생합성유전자를 보유한 것으로 확인되었다. 본 연구는 GH1-13균주가 작물의 생육촉진과 병 방제를 동시에 해결할 수 있는 강력한 복합기능성 미생물제로의 가능성이 있음을 보여주었다.

• 한국균학회지
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• 제40권2호
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• pp.118-123
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• 2012

대표적인 감귤 녹색곰팡이병(Penicillium digitatum) 방제용 생물농약을 개발하고자 제주도내 7개 과수원으로부터 채집된 citrus 잎에서 21균주의 내생세균을 분리하였다. 그 중 5개의 세균이 녹색곰팡이병균 P. digitatum에 항균활성을 나타냈으며, 대치배양에서 가장 강력한 항균활성을 보인 CB3 균주가 선발되었다. CB3 균주는 간상형의 그람 양성세균으로 생리 생화학적 특성과 gyrA 유전자 염기서열 분석에 의해 Bacillus velezensis로 동정되었다. CB3 균주는 감귤 저장병 병원균 Penicillium digitatum에 강력한 항균활성을 나타내었다. $1{\times}10^5$ spores/ml에 이르는 고농도의 P. digitatum을 감귤에 상처접종했을 때에도, $1{\times}10^8$ cfu/ml의 CB3에 의한 방제효과는 66.7%로 매우 높았다. 본 연구결과, Bacillus velezensis CB3의 안정성과 강한 방제활성 등을 고려할 때 유용 친환경적 방제제로서 매우 가치가 있을 것으로 판단된다.

• 한국어병학회지
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• 제32권2호
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• pp.69-80
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• 2019

We performed MLSA (multilocus sequence analysis) and phenotypic characterization of Aliivibrio species isolated from walleye pollock (Gadus chalcogrammus) maintained in 3 different facilities of Gangwon Province, the east coast of Korea. Of 38 Aliivibrio species identified by 16S rDNA sequences, 12 strains were randomly selected and MLSA was conducted with 5 house-keeping genes (gapA, gyrB, pyrH, recA and rpoA) and 16S rDNA gene. Phylogenetic analysis and homology of the concatenated sequences (4,580 bp) with other Vibrionaceae genera revealed that 4 strains (GNGc16.1, YYGc16.1, YYGc16.2, GSGc18.1) were identified as Aliivibrio logei and one strain (GSGc16.1) as A. wodanis. One strain (GSGc17.1) was tentatively identified as A. logei, but needs further analysis because it did not belong to the same clade with A. logei type strain. 6 strains (GSGc17.2, GNGc16.2, GSGc16.2, GSGc17.3, GSGc18.2, GSGc17.4) need further investigation as potential novel species. Either phenotypic characterization or 16S rDNA sequence alone did not provide enough information for identification of Aliivibrio strains at the species level. A. logei and A. wodanis are generally known as non-pathogenic bacteria, but also known as opportunistic or secondary pathogens of cold water fishes. Cares should be taken to prevent potential outbreaks due to these bacteria, although there was no outbreaks during the sampling period.

• 천문학회보
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• 제37권1호
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• pp.32.2-32.2
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• 2012

Gamma Ray Bursts (GRBs) are the most energetic events in the universe, and are known to arise from the death of massive stars in many cases. Their extreme brightness makes it possible to detect them at very high redshift (z > 6.5), well into the epoch of re-ionization, providing us with an opportunity to investigate the deaths of the first stars when the universe was much younger than 1 Gyr. Here, we report the discovery of GRB 100905A, a GRB at $z$ - 7.5 (age of the universe at 700 Myr). Our observation revealed a strong spectral break between z and J band, allowing us to estimate its photometric redshift. Its gamma-ray light curve shows a very short duration of about 0.7 sec, the shortest duration event at z > 5. Investigation of this and three other known GRBs at z > 6.5 reveals that they are all short duration bursts. This is puzzling, considering that GRBs from death of massive stars do not show short duration. We suggest two possible explanations for this: (i) the BAT light curves of the high redshift GRBs suffered from observational selection effect where we are only observing the very tip of the light curve; (ii) the stars in the early universe had a peculiar nature that are different from ordinary stars at lower redshifts.

• The Plant Pathology Journal
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• 제32권5호
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• pp.431-440
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• 2016

In 2004, bacterial spot-causing xanthomonads (BSX) were reclassified into 4 species-Xanthomonas euvesicatoria, X. vesicatoria, X. perforans, and X. gardneri. Bacterial spot disease on pepper plant in Korea is known to be caused by both X. axonopodis pv. vesicatoria and X. vesicatoria. Here, we reidentified the pathogen causing bacterial spots on pepper plant based on the new classification. Accordingly, 72 pathogenic isolates were obtained from the lesions on pepper plants at 42 different locations. All isolates were negative for pectolytic activity. Five isolates were positive for amylolytic activity. All of the Korean pepper isolates had a 32 kDa-protein unique to X. euvesicatoria and had the same band pattern of the rpoB gene as that of X. euvesicatoria and X. perforans as indicated by PCR-restriction fragment length polymorphism analysis. A phylogenetic tree of 16S rDNA sequences showed that all of the Korean pepper plant isolates fit into the same group as did all the reference strains of X. euvesicatoria and X. perforans. A phylogenetic tree of the nucleotide sequences of 3 housekeeping genes-gapA, gyrB, and lepA showed that all of the Korean pepper plant isolates fit into the same group as did all of the references strains of X. euvesicatoria. Based on the phenotypic and genotypic characteristics, we identified the pathogen as X. euvesicatoria. Neither X. vesicatoria, the known pathogen of pepper bacterial spot, nor X. perforans, the known pathogen of tomato plant, was isolated. Thus, we suggest that the pathogen causing bacterial spot disease of pepper plants in Korea is X. euvesicatoria.