• 한국동물학회:학술대회논문집
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• 한국동물학회 1995년도 한국생물과학협회 학술발표대회
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• pp.289.2-289
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• 1995

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• Journal of Microbiology
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• 제45권6호
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• pp.558-565
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• 2007

Using microarray analysis, we determined those Salmonella genes induced at the entry of stationary phase, and subsequently discovered that uncharacterized yliH was induced most dramatically. We set out to establish the molecular mechanism underlying the stationary phase induction of yliH under the standard culture condition, LB with vigorous aeration, by analyzing its promoter activity in various mutant backgrounds, lacking stationary phase ${\sigma}$, $RpoS^-$, or stringent signal molecules ppGpp, ${\Delta}relA$ ${\Delta}spoT$. It was found that the stationary phase induction of yliHp was partially dependent on rpoS but entirely dependent on ppGpp. DNA sequence analysis revealed that the Salmonella yliH gene is composed of 381 base-pair nucleotides, with overall amino acid sequence revealing 76.38% amino acid identity and 88.98% similarity with Escherichia coli yliH, although no motif from data base was noted for its possible role. Recently however, it has been reported that yliH in E. coli was implicated in biofilm formation and motility by repressing these activities (Domka et al., 2006). We have constructed a mutant Salmonella deleting yliH gene by allele replacement and examined its phenotype, and found that the yliH in Salmonella more or less affects motility and adherence by enhancing these activities. The effect on biofilm formation in Salmonella was uncertain. Moreover, addition of cloned yliH of E. coli into Salmonella did not reduce motility or adherence. Taken together, it appears that the pathways implicating yliH for biofilm formation and motility in E. coli and in Salmonella are somewhat different.

• Journal of Microbiology
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• 제45권6호
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• pp.492-498
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• 2007

GacS and GacA proteins form a two component signal transduction system in bacteria. Here, Tn5 transposon gacS and gacA (Gac) mutants of Pseudomonas sp. KL28, an alkylphenol degrader, were isolated by selecting for smooth colonies of strain KL28. The mutants exhibited reduced ability to migrate on a solid surface. This surface motility does not require the action of flagella unlike the well-studied swarming motility of other Pseudomonas sp. The Gac mutants also showed reduced levels of biofilm and pellicle formation in liquid culture. In addition, compared to the wild type KL28 strain, these mutants were more resistant to high concentrations of m-cresol but were more sensitive to $H_2O_2$, which are characteristics that they share with an rpoS mutant. These results indicate that the Gac regulatory cascade in strain KL28 positively controls wrinkling morphology, biofilm formation, surface translocation and $H_2O_2$ resistance, which are important traits for its capacity to survive in particular niches.

• Annals of Clinical Microbiology
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• 제17권1호
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• pp.23-27
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• 2014

신속발육항산균은 자연환경에서 흔히 검출되는 균으로, 기회감염병원체로 인체감염의 주요 원인균으로서 인식되고 있다. M. conceptionense는 분자역학적 분석을 통해 M. fortuitum의 세번째 생체변이종에서 분리되어 새로운 종으로 명명되었다. 그러나 이 균에 의한 감염 보고는 많지 않고 특히 수술후 창상 감염에 대한 보고는 거의 없다. 이에 저자들은 16S rRNA, hsp65 및 rpoB 유전자 염기순서분석을 이용하여 동정한 M. conceptionense에 의한 수술 후 창상감염을 보고하고자 한다.

• The Plant Pathology Journal
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• 제34권1호
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• pp.1-10
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• 2018

A previously unreported bacterial disease on chili pepper (Capsicum annuum L.) seedlings affecting as many as 4% of seedlings was observed in greenhouses in Chihuahua, Mexico (Delicias and Meoqui counties). Initial lesions appeared as irregular small spots on leaves and brown necrosis at margins tips were observed. Later, the spots became necrotic with a chlorotic halo. Advanced disease was associated with defoliation. A Gram negative, rod-shaped bacterium was isolated from diseased chili pepper seedlings. Three inoculation methods revealed that isolated strains produce foliage symptoms, similar to those observed in naturally infected seedlings. Pathogenic strains that caused symptoms in inoculated seedlings were re-isolated and identified to fulfill koch's postulate. Polyphasic approaches for identification including biochemical assays (API 20E and 50CH), carbon source utilization profiling (Biolog) and 16S rDNA, hsp60 and rpoB sequence analysis were done. Enterobacter cloacae was identified as the causal agent of this outbreak on chili pepper seedlings.

• 한국산림과학회지
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• 제108권2호
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• pp.200-207
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• 2019

본 연구는 한국 전나무(Abies holophylla) 및 2종의 일본 전나무(A. firma 및 A. homolepis), 그리고 우리나라 법정 보호 전나무 간의 구별을 위한 기초자료를 제공하기 위하여 수행하였다. 각각 조사대상목의 잎 끝의 형태적 특성을 분석한 결과, A. holophylla는 뾰족한 형태를 보였고, 반면에 A. firma와 A. homolepis는 미요두(微凹頭) 형태를 보였다. 그리고 법정 보호 전나무의 잎 끝은 원두(圓頭) 형태를 보였다. 각각 전나무 종들 간의 잎 기공수를 비교한 결과, A. holophylla와 A. firma의 잎 기공수는 통계적으로 유의한 차이가 없었으며, A. homolepis와 법정 보호 전나무의 잎 기공수는 매우 유사한 것으로 보였다. 엽록체 DNA 바코드(matK, atpF-atpH, rpoC2-rps2, rpoC1, psbA-trnH)를 이용하여 전나무 종간 유전적 차이를 비교 분석하였다. 그 결과, atpF-atpH와 psbA-trnH 영역에서 A. firma와 다른 전나무 종들 간의 분명한 염기서열의 차이가 있었다. 하지만, 종명이 분명히 다른 한국 전나무(A. holophylla)와 일본 전나무(A. homolepis)간에 엽록체 염기 서열차이가 전혀 없으며, 또한 법정 보호 전나무와도 차이가 없었다. 따라서 이들 종간의 유전적 차이에 대한 구체적인 연구의 진행이 필요하다고 본다.

• 한국미생물·생명공학회지
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• 제50권2호
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• pp.301-309
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• 2022

본 연구에서는 제럼본에 처리에 의해 유도된 H. pylori 유전자의 전사적 변화를 분석하였다. NGS를 사용하여 RNA 발현 변화를 분석한 다음 그 결과를 검증하기 위해 RT-PCR을 수행하였다. NGS 분석 결과, 1,632개의 유전자 중 총 23개가 제럼본 처리에 의해 유의하게 발현이 변화된 특이발현 유전자로 분석되었다. DNA 복제와 전사, 병원성 인자 및 T4SS 성분과 관련된 유전자 중 10개는 현저하게 하향 조절되었고 5개는 상향 조절되었다. RT-PCR을 이용하여 유전자의 발현 수준을 재확인하였고 그 결과, 14개 유전자에서 NGS와 동일하게 발현 양상이 변화하였다. RT-PCR은 제럼본 처리에 의해 10개의 유전자(dnaE, dnaQ, rpoA, rpoD, secA, flgE, flhA, virB5, virB8, virB9)의 발현 감소와 4개의 유전자(flaA, flaB, virB4, virD4)의 발현 증가를 보였다. 이러한 본 연구의 결과는 제럼본이 다양한 H. pylori의 병원성과 관련된 인자들을 조절함으로써 H. pylori 감염의 잠재적인 치료제가 될 수 있음을 시사한다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.99.1-100
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• 2003

E. intermedium Blocontrol activity of a P. chlororaphis rhizobacteium O6, depends to the synthesis of extracellular secondary metabolites and exoenzymes, thought to antagonize the pathogenicity of a variety of phytopathogenic fungi. The production of secondary metabolites and exoenzymes in O6, depends essentially on the GacS-mediated signal transduction pathway, which activates largely unknown signal transduction pathway. To exploit the GacS-mediated signal transdcution pathway involved in activation of ph genes that are necessary for biosynthesis of phenazine from P. chlororaphis O6, we cloned and sequenced the phz operon, rpoS gene encoding stationary specific sigma factor, ppx gene encoding polyphosphatase, and lon gene encoding ion protease. Expression of each gene in wild type and GacS mutant were analyzed by RT-PCR. Transcripts from rpoS, phzI enconing acylhomoserine lactone (AHL) synthase, and ph structural genes in the GacS mutant were reduced in each of these growth phases compared to the wild type. The GacS or Lon mutant was found to be deficient in the production of phenzines, exoenzymes, and the acylhomoserine lactone. These mutants were not complemented by ph operon and addition of exogenous AHL. These results indicate that the GacS global regulatory systems controls phenazine production at multiple levels. Future research will focus to identifying the GacS-mediated regulatory cascade involving in production of phenazine in P. chlororaphis.

• Journal of Microbiology and Biotechnology
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• 제27권1호
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• pp.112-121
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• 2017

Edwardsiella tarda is a gram-negative pathogenic bacterium in aquaculture that can cause hemorrhagic septicemia in fish. Many secreted proteins have already been identified as virulent factors of E. tarda. Moreover, since virulent phenotypes are based on the expression regulation of virulent genes, understanding the expression profile of virulent genes is important. A quantitative RT-PCR is one of the preferred methods for determining different gene expressions. However, this requires the selection of a stable reference gene in E. tarda, which has not yet been systematically studied. Accordingly, this study evaluated nine candidate reference genes (recA, uup, rpoB, rho, topA, gyrA, groEL, rpoD, and 16S rRNA) using the Excel-based programs BestKeeper, GeNorm, and NormFinder under different culture conditions. The results showed that 16S rRNA was more stable than the other genes at different culture growth phases. However, at the same culture time, topA was identified as the reference gene under the conditions of different strains, different culture media, and infection, whereas gyrA was identified under the condition of different temperatures. Thus, in experiments, the expression of gapA and fbaA in E. tarda was analyzed by RT-qPCR using 16S rRNA, recA, and uup as the reference genes. The results showed that 16S rRNA was the most suitable reference gene in this analysis, and that using unsuitable reference genes resulted in inaccurate results.

• 한국어병학회지
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• 제31권2호
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• pp.87-92
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• 2018

본 연구는 육상 순환 양식장, 약 $20^{\circ}C$의 수온에서 양식 중이던 자주복에서 체표에 백탁과 궤양을 보이는 개체가 다수 발생하여 그 원인을 밝히고자 하였다. TCBS 선택배지에서 순수 배양된 균체를 확인하고 계대 배양하여 16S rRNA와 rpoA 유전자의 염기서열 분석을 실시하였으며, 그 결과는 Vibrio atlanticus와 99.77%의 상동성을 가지는 것으로 나타났다. 생화학적 특징을 이미 보고된 같은 균종과 비교한 결과, Voges-Proskauer test와 Gelatin 가수분해능에 대한 결과에서 차이를 나타내는 것으로 확인하였다.