• The Plant Pathology Journal
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• 제35권5호
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• pp.445-458
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• 2019

The lipopolysaccharide (LPS) composed of lipid A, core, and O-antigen is the fundamental constituent of the outer membrane in gram-negative bacteria. This study was conducted to investigate the roles of LPS in Burkholderia glumae, the phytopathogen causing bacterial panicle blight and seedling rot in rice. To study the roles of the core oligosaccharide (OS) and the O-antigen region, mutant strains targeting the waaC and the wbiFGHI genes were generated. The LPS profile was greatly affected by disruption of the waaC gene and slight reductions were observed in the O-antigen region following wbiFGHI deletions. The results indicated that disruption in the core OS biosynthesis-related gene, waaC, was associated with increased sensitivity to environmental stress conditions including acidic, osmotic, saline, and detergent stress, and to polymyxin B. Moreover, significant impairment in the swimming and swarming motility and attenuation of bacterial virulence to rice were also observed in the waaC-defective mutant. The motility and virulence of O-antigen mutants defective in any gene of the wbiFGHI operon, were not significantly different from the wild-type except in slight decrease in swimming and swarming motility with wbiH deletion. Altogether, the results of present study indicated that the LPS, particularly the core OS region, is required for tolerance to environmental stress and full virulence in B. glumae. To our knowledge, this is the first functional study of LPS in a plant pathogenic Burkholderia sp. and presents a step forward toward full understanding of B. glumae pathogenesis.

• Journal of Microbiology and Biotechnology
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• 제15권2호
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• pp.376-383
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• 2005

Alcaligenes sp. JMP228 carrying 2,4­dichlorophenoxyacetic acid (2,4-D) degradative plasmid pJP4 was inoculated into natural soil, and transfer of the plasmid pJP4 to indigenous soil bacteria was investigated with and without 2,4-D amendment. Plasmid pJP4 transfer was enhanced in the soils treated with 2,4-D, compared to the soils not amended with 2,4-D. Several different transconjugants were isolated from the soils treated with 2,4-D, while no indigenous transconjugants were obtained from the unamended soils. Inoculation of the soils with both the donor Alcaligenes sp. JMP228/pJP4 and a recipient Burkholderia cepacia DBO 1 produced less diverse transconjugants than the soils inoculated with the donor alone. Repetitive extragenic palindromic-polymerase chain reaction (REP-PCR) analysis of the transconjugants exhibited seven distinct genomic DNA fingerprints. Analysis of 16S rDNA sequences indicated that the transconjugants were related to members of the genera Burkholderia and Pandoraea. Denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA genes revealed that inoculation of the donor caused clear changes in the bacterial community structure of the 2,4-D­amended soils. The new 16S rRNA gene bands in the DGGE profile corresponded with the 16S rRNA genes of 2,4-D­degrading transconjugants isolated from the soil. The results indicate that introduction of the 2,4-D degradative plasmid as Alcaligenes sp. JMP228/pJP4 has a substantial impact on the bacterial community structure in the 2,4-D-amended soil.

• Asian-Australasian Journal of Animal Sciences
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• 제27권10호
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• pp.1461-1468
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• 2014

This study was aimed to examine the antibacterial and antioxidative properties of seven edible plants from Thailand to develop alternative antibiotics as feed additives. The plants include Citrus aurantifolia Swingle (Lime) fruits and its leaves, Sesbania grandiflora L. (Agati sesbania) leaves, Piper sarmentosum Roxb (Wild betal) leaves, Curcuma domestica Valeton (Turmeric) roots, Morinda citrifolia L. (Beach mulberry) leaves, Cassia siamea britt (Siamea cassia) leaves, and Cocos nucifera L. (Coconut) peels. The plants were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. Antibacterial activities with minimum inhibitory concentration (MIC) were determined by agar diffusion assay against Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, and Clostridium perfringens that were considered pathogenic strains in livestock infection. Methanol extracts of C. aurantifolia Swingle fruits and leaves showed the broadest spectrum of antibacterial activities except for C. perfringens. Butanol extract of S. grandiflora L. leaves showed the strongest activity against Burkholderia sp. with MIC, $135{\mu}g/mL$. P. sarmentosum Roxb leaves showed antibacterial activities against E. coli, Burkholderia sp. and H. parasuis. Ethyl acetate and water extracts from C. domesitca Valeton roots showed MIC of $306{\mu}g/mL$ and $183{\mu}g/mL$, respectively against only C. perfringens. Antioxidative activity was determined by 2-diphenyl-2-picryl hydrazyl photometric assay. The methanol extracts of C. aurantifolia Swingle fruits and P. sarmentosum Roxb leaves showed the highest antioxidant activity among all the extracts with 3.46 mg/mL and 2.70 mg/mL effective concentration 50% ($EC_{50}$) values, respectively. Total contents of phenolics and flavonoids were measured from the plant extracts. Methanol extracts of S. grandiflora L. and chloroform extracts of C. domestica Valeton were found to have the highest amount of total phenolics, 41.7 and $47.8{\mu}g/mL$, respectively. Flavonoid content of methanol extracts in S. grandiflora L. T was $22.5{\mu}g/mL$ and the highest among plant extracts tested. These results indicated that C. aurantifolia Swingle, S. grandiflora L., P. sarmentosum Roxb, and C. domestica Valeton have antibacterial and antioxidant activities and can be used as alternative antibiotics or potential feed additives for the control of animal pathogenic bacteria.

• 미생물학회지
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• 제41권1호
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• pp.13-17
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• 2005

본 연구에서는 이 전 연구에서 단일 탄소원과 질소원 및 에너지원으로 aniline을 이용하는 Delftia sp. JK-2에서 분리, 정제된 바 있는 C2,3O의 N-말단 아미노산과 DNA 서열을 분석하였다. Aniline에서 배양한 Delftia sp. JK-2에서 분리된 약 35kDa의 C2,3O의 N-말단 아미노산 서열을 분석 한 결과 $^1MGVMRIGHASLKVMDMDAAVRHYENV^{26}$로 Pseudomonas sp. AW-2와 Comamonas sp. JS765의 C2,3O와 일치하는 것으로 나타났다. 위에서 확인된 아미노산 서열을 바탕으로 제작된 primer와 JK-2의 total genomic DNA를 기질로 사용하여 PCR을 수행한 결과 약 950 bp의 유전자 증폭산물을 획득하였다. 이 증폭산물 중 정확히 확인된 890 bp의 염기서열을 분석한 결과 Delftia JK-2의 C2,3O유전자 염기서열은 Pseudomonas su. AW-2의 C2,3O와 일치하였으며 Comamonas sp. Js765의 C2,3O와 $97\%$의 높은 상동성을 나타내었다.

• 식물병연구
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• 제25권4호
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• pp.179-187
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• 2019

이 연구는 플라즈마 기술 (radio frequency-thermal plasma system과 direct current sputtering system)을 이용하여 제작된 나노 금속복합체를 이용하여 박과 작물(수박, 호박, 박)의 종자에서 분리한 미생물의 항균 활성 효과를 검정하기 위하여 실험을 진행하였다. 8종의 나노 금속복합체와 4가지의 담체를 이용하여 5종의 곰팡이와 10종의 세균을 대상으로 기내 실험을 수행하였다. 그 결과, 곰팡이를 대상으로 한 항균실험에서 나노 금속복합체 Brass/CaCO₃의 경우 1,000 ppm 농도에서 5종의 곰팡이에 대하여 100%의 항균효과를 나타내었다. 세균을 대상으로 한 항균실험의 경우 나노 금속복합체 Brass/CaCO₃(1,000 ppm)은 Weissella sp., Rhodotorula mucilaginosa, Burkholderia sp. 그리고 Enterococcus sp. 4가지 세균을 100% 억제하는 것으로 확인되었다. 나노 금속복합체 G-Ni은 Rhizopus stolonifer에 대하여 100% 항균효과를 나타냈으며, 4가지 곰팡이에 대해서는 52.94-71.76% 정도의 항균효과를 나타내었다. 하지만 나노 금속복합체 G-Ni은 10종의 세균에 대해서는 효과가 없는 것으로 나타났다. 요약하면, 8가지 나노 금속복합체와 4가지 담체 중에서 Brass/CaCO₃가 5종의 곰팡이와 4종의 세균 대하여 항균효과가 있었으며, G-Ni는 5종의 곰팡이에 대해서 52.94-100% 효과를 보였으나 세균에 대해서는 항균효과가 없는 것으로 확인되었다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2005년도 International Symposium & conference of the Plant Resources Society of Korea
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• pp.179-179
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• 2005

• 유기물자원화
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• 제19권4호
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• pp.84-89
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• 2011

퇴비 제조시 유용한 수분조절제로 각광받고 있는 코코피트를 대상으로 섬유소 분해능을 지닌 세균을 분리 동정하였다. 각기 다른 코코피트를 시료로 하여 섬유소 분해세균을 분리한 결과 각 시료로부터 다양한 세균들이 검출되었으며 이들을 동정한 결과 Burkholderia sp., Bacillu subtilis, Sphingomonas sp., Rhodotorula sp.를 비롯하여 여러 Pseudomonas sp. 등이 동정되었다. 이들 중 4종류의 균주, 즉 B. subtilis, P. aeruginosa, P. stutzeri, P. luteola 를 선별하여 이들의 생화학적 특성을 분석하였으며 배양액을 대상으로 섬유소 분해효소의 일종인 CMCase의 활성을 비교 분석하였다. CMCase의 활성비교를 위한 표준균주로 Cellulomonas sp.를 사용하였으며 비교결과 P. aeruginosa, P. stutzeri, B. subtilis, P. luteola 균주에서 각각 표준균주 효소활성의 83%, 40%, 8%, 6% 정도인 것으로 분석되었다.

• 한국미생물·생명공학회지
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• 제35권1호
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• pp.1-10
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• 2007

한반도 중부지방인 충청남북도 7개 지역에서 재배되고 있는 벼 시료 21점을 채집하여 이들의 뿌리를 표면살균 한 후 내생균을 44주 분리하고 내생성 검정 시스템을 통해 정착력이 상대적으로 우수한 균주를 최종 16주 확보 하였다. 이들의 분리빈도는 뿌리 생체중 1g당 $10^{3-5}$ CFU로 나타났다. 흥미롭게도 이중 7주가 Eurkholderia 속 균으로 동정되어 기존의 다른 벼 내생세균 연구 결과와는 다른 특징을 보였다. 또한 GFP tagging 방법을 이용하여 분리균주 중 하나인 Enterobacter sp. KJ001 균주에 대해 뿌리조직 내 colonization 위치를 확인해본 결과 뿌리 조직 중 관다발 주변에 군락을 이루고 있음을 관찰하였다. Burkholderia 분리주들은 국내 재배 벼에서 높은 빈도로 분리되며 in vitro상에서 광범위한 진균성 식물병원균에 대해 우수한 길항력과 더불어 대부분 질소고정 관련 유전자인 nifH를 가지는 점으로 보아 질소고정에 의해 식물생육에 도움을 줄 수 있을 것으로 예측되며 실제로 오이 유묘의 생장을 30% 이상 촉진하는 효과를 보여 식물병 억제 및 감소와 더불어 작물의 생장 촉진 및 생산성 증대에 활용가치가 높은 내생균으로 사료된다.

• Journal of Microbiology
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• 제35권2호
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• pp.117-122
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• 1997

Several dominant 4-CPA-degrading bacteria were isoalted from agricultural soils. Most of the isolates were identified as Burkholderia species by fatty acid methyl ester (FAME) analysis, but they were idstinct in chromosomal patterns obtained by PCR amplification of repetitive extragenic palindromic (REP) sequences. These strains were generally restricted in their substrate utilization capabilities. The 4-CPA degradative enzymes were idnducible by 4-CPA and some isolates appeared to mineralize 4-CPA via formation of 4-chlorophenol and 4-chlorocatechol as intermediates during its biodegradation pathway. Plasmid DNAs were not detected from most of the isoaltes and their 4-CPA genes wer on the chromosomal DAN. The 4-CPA degradation patterns in axenic cultures and natural soils varied depending on the strains and soils. The inoculation of 4-CPA degraders much improved the removal of 4-CPA from the 4-CPA treated soils.

• Journal of Microbiology and Biotechnology
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• 제27권6호
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• pp.1138-1149
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• 2017

The use of microalgal biomass is an interesting technology for the removal of heavy metals from aqueous solutions owing to its high metal-binding capacity, but the interactions with bacteria as a strategy for the removal of toxic metals have been poorly studied. The goal of the current research was to investigate the potential of Burkholderia tropica co-immobilized with Chlorella sp. in polyurethane discs for the biosorption of Hg(II) from aqueous solutions and to evaluate the influence of different Hg(II) concentrations (0.041, 1.0, and 10 mg/l) and their exposure to different contact times corresponding to intervals of 1, 2, 4, 8, 16, and 32 h. As expected, microalgal bacterial biomass adhered and grew to form a biofilm on the support. The biosorption data followed pseudo-second-order kinetics, and the adsorption equilibrium was well described by either Langmuir or Freundlich adsorption isotherm, reaching equilibrium from 1 h. In both bacterial and microalgal immobilization systems in the co-immobilization of Chlorella sp. and B. tropica to different concentrations of Hg(II), the kinetics of biosorption of Hg(II) was significantly higher before 60 min of contact time. The highest percentage of biosorption of Hg(II) achieved in the co-immobilization system was 95% at pH 6.4, at 3.6 g of biosorbent, $30{\pm}1^{\circ}C$, and a mercury concentration of 1 mg/l before 60 min of contact time. This study showed that co-immobilization with B. tropica has synergistic effects on biosorption of Hg(II) ions and merits consideration in the design of future strategies for the removal of toxic metals.