• Animal cells and systems
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• 제6권3호
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• pp.271-275
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• 2002

Rph1 and Gisl are damage-responsive repressors involved in PHR1 expression. They have two $C_{2}$H/ sub 2/ zinc finger motifs as putative DNA binding domains and N-terminal conserved domain with unknown function. They are also found in the human retinoblastoma binding protein 2 and the mouse jumonji- encoded protein. The repressors are able to bind to A $G_{4}$ sequence within a 39-bp sequence called upstream repressing sequence of PHR1 promoter (UR $S_{PHR1}$) responsible for the damage-response of PHR1. We report here that Rph1 is predominantly localized in the nucleus as examined by fluorescence microscopic analysis with GFP-Rph1 fusion protein. On the basis of the fact that the A $G_{4}$ sequence that is recognized by Rph1 and Gisl is also recognized by Msn2 and Msn4 in a process of stress response, we a1so tried to examine the in vivo function of A $G_{4}$ and the role of Msn2 and Msn4 in PHR1 expression. Our results demonstrate that Msn2 and Msn4 are actually required for the basal transcription of PHR1 expression but not for its damage induction. When A $G_{4}$ sequence was inserted into the minimal promoter of the cyc1-LacZ reporter, the increased LacZ expression was observed indicating its involvement in transcriptional activation. The data suggest that the A $G_{4}$ is primarily required for basal transcriptional activation of PHR1 or CYC1 promoter through the possible involvement of Msn2 and Msn4. However, since the A $G_{4}$ is also involved in the repression of PHR1 via Rphl and Gisl, it is proposed that A $G_{4}$ functions as either URS or upstream activating sequence (UAS) depending on the promoter context.t.

• Journal of Microbiology
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• 제40권4호
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• pp.305-312
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• 2002

The effects of two natural polyamines (putrescine and spermidine) on the synthesis of ArcA, a response regulator of the Arc two-component signal transduction system, were studied using an E. coli mutant deficient in polyamine biosynthesis. Endogenous polyamine deficiency of the mutant resulted in marked reduction in the ArcA level determined by Western blot analysis. Putrescine supplement to the growth medium effectively increased the ArcA level of the mutant in a concentration-dependent manner. Spermidine also stimulated the ArcA level in the mutant to a greater degree than putrescine. Expression of arcA'::lacZ operon fusion in the mutant was stimulated 6-fold and 10-fold by putrescine and spermidine at a 1mM concentration, respectively, indicating that the stimulatory effect of the polyamines on ArcA synthesis is due to transcriptional induction, and that spermidine is a more potent arcA inducer than putrescine. The polyamine-dependent arcA'::lacZ induction was growth-phase-dependent and independent of either arcA or fnr which are two regulators involved in anaerobic stimulation of the Arch level. These results suggested that putrescine and spermidine polyamines may be potential intracellular signal molecules in the control of arcA expression, and thereby may play an important role in cellular metabolism.

• 생태와환경
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• 제38권4호통권114호
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• pp.510-517
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• 2005

선형의 남조류 아나베나는 광합성과 질소고정 능이 있으며, 이는 아마도 이 남조류가 각종 육수 환경에 잘 적응하는데 큰 역할을 했다고 볼 수 있다. 작은 patS라는 유전자는 질소 고정세포의 형성을 막으며 결과적으로 질소원이 부족한 환경에서 아나베나의 죽음을 가져온다. 본 연구는 patS 유전자 주변의 DNA 염기 서열을 분석하여 codon 활용도를 알아 본 결과 patS를 제외한 다른 유전자가 존재하지 않음을 밝혔다. patS를 포함하는 세 개의 겹치는 cosmid를 찾아서 기존의 알려진 이형세포 발달 유전자를 탐색하였으나 나타나지 않았다. 질소원의 결핍에 반응하는 patS 유전자의 발현을 Northern blot 분석과 lacZ reporter 유전자 합성 실험을 통하여 각각 전사와 번역의 단계에서 알아보았다. patS 유전자의 발현은 배지로부터 질소원이 제거된 후 12시간 내에 급격히 증가하는 것으로 나타났다.

• Journal of Microbiology
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• 제42권4호
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• pp.353-356
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• 2004

In a previous study, a gst gene was isolated from the fission yeast Schizosaccharomyces pombe. This gene was dubbed gstI, and was characterized using the gstI -lacZ fusion plasmid pYSH2000. In this work, four additional fusion plasmids, pYSHSDl, pYSHSD2, pYSHSD3 and pYSHSD4, were constructed, in order to carry (respectively) 770, 551, 358 and 151 bp upstream regions from the translational initiation point. The sequence responsible for induction by aluminum, mercury and hydrogen peroxide was located in the range between -1,088 and -770 bp upstream of the S. pombe gstI gene. The same region was identified to contain the nucleotide sequence responsible for regulation by Papl, and has one puta­tive Papl binding site, TTACGTAT, located in the range between $-954\~-947$ bp upstream of the gstI gene. Negatively acting sequences are located between -1,088 and -151 bp. These findings imply that the Papl protein is involved in basal and inducible transcription of the gstI gene in the fission yeast S. pombe.

• The Plant Pathology Journal
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• 제18권2호
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• pp.57-62
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• 2002

In vivo expression technology (IVET) has been developed to study bacterial gene expression in Salmonella typhimurium during host infection. The expression of selected genes by IVET has been elevated in vivo but not in vitro. The selected genes turned out to be important for bacterial virulence and/or pathogenicity. IVET depends on a synthetic operon with a promoterless transcriptional fusion between a selection marker gene and a reporter gene. The IVET approach has been successfully adapted in other bacterial pathogens and plant-associated bacteria using different selection markers. Pseudomonas putida suppresses citrus root rot caused by Phytophthora parasitica and enhances citrus seedling growth. The WET strategy was adapted based on a transcriptional fusion, pyrBC'-lacZ, in P. putida to study the bacterial traits important far biocontrol activities. Several genes appeared to be induced on P. parasitica hyphae and were found to be related with metabolism and regulation of gene expression. It is likely that the biocontrol strain took a metabolic advantage from the plant pathogenic fungus and then suppressed citrus root rot effectively. The result was parallel with those from the adaptation of IVET in P. fluorescens, a plant growth promoting rhizobacteria (PGPR). Interestingly, genes encoding components for type III secretion system have been identified as rhizosphere-induced genes in the PGPR strain. The type III secretion system may play a certain role during interaction with its counterpart plants. Application of IVET has been demonstrated in a wide range of bacteria. It is an important strategy to genetically understand complicated bacterial traits in the environment.

• Journal of Microbiology
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• 제45권6호
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• pp.583-589
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• 2007

The promoter region of pyrC (dihydroorotase) gene of Escherichia coli was shown to have Fur protein binding properties by gel retardation assay. In vivo regulation of the pyrC expression was studied by measuring dihydroorotase activity and ${\beta}$-galactosidase level in the $fur^+$ and $fur^-$ genetic background. The expression of chromosomal dihydroorotase activity and ${\beta}$-galactosidase activity of pyrC-lacZ fusion plasmid was repressed to about 30% and 17%, respectively in the $fur^+$ strain compared to those in the $fur^-$ strain. Divalent ions such as $Fe^{2+}$ and $Zn^{2+}$ were not required for the repression. PyrC expression was also reduced to one half by 1 mM uracil. The effect of uracil was independent on the fur gene.

• 환경위생공학
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• 제11권2호
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• pp.9-20
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• 1996

Genotoxicity/mutagenicity of organic chemicals in industrial wastewater was investigated using umu-test with a Salmonella typhimurium TA1535 strain. The tester strain was derived by introducing plasmid pSK 1002, which carried a umu C - lac Z fusion gene into S typhimurium TA1535, and tester strain in the presence microsomal activation proved to be the more sensitive maker of genotoxicity. Genotoxic responses were observed in concentrated with a blue-rayon column, from 14 plants tested. The results were as follow; 1. Genotoxic responses were observed in concentrated from nine plants(64.3%) tested. 2. The results show that genotoxic activity was particulary high in the untreated wastewaters and decreased in the treated wastewaters(35.7%) 3. No significant correlation was found between genotoxicity and water ollution indicators, such as COD and BOD.

• Journal of Microbiology and Biotechnology
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• 제19권12호
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• pp.1527-1535
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• 2009

Polyphosphate (polyP) plays diverse physiological functions in prokaryotes and eukaryotes, but most of their detailed mechanisms are still obscure. Here, we show that deletion of polyphosphate kinase (PPK), the principal enzyme responsible for synthesis of polyP, resulted in augmented expression of cAMP receptor protein (CRP) and rpoS and lowered $H_2O_2$ sensitivity in Salmonella Typhimurium ATCC14028. The binding of cAMP-CRP complex to rpoS promoter and further stimulation of its transcription were proved through electrophoretic mobility shift assay, lacZ fusion, and exogenous cAMP addition, respectively. The rpoS expression increased in cpdA (cAMP phosphodiesterase coding gene) mutant, further suggesting that cAMP-CRP upregulated rpoS expression. These results demonstrate that PPK affects oxidative stress response by modulating crp and rpoS expression in S. Typhimurium.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2001년도 학술 발표회 진행표 및 논문초록
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• pp.64-64
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• 2001

Escherichia coli has developed soxRS regulon to defend against toxicity of superoxide radical. SoxR, superoxide sensor, is oxidized by superoxide-generating agents or nitric oxide and oxidized SoxR activates the transcription of soxS gene. In order to find out the trans-acting factors regulating SoxR activity in vivo, soxS：：lacZ single copy operon fusion construct was prepared and random Tn10 insertional mutatons were performed.(omitted)

• 생명과학회지
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• 제9권2호
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• pp.169-175
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• 1999

Salmonella typhimurum은 생활사 동안에 다양한 환경과 접하게 된다. S. typhimurium은 오염된 웅덩이에서 숙주의 phgolysosome에 이르기까지 생태계에 널리 분포하면서 산성 스트레스를 경험하며 또한 생존할 수 있다. Salmonella 이와 같은 산저항능은 Acid Tolerance Response (ATR)에 의해 획득된다. 약산의 pH에 적응된 S. typhimurium은 낮은 pH 영역에서 생존할 수 있는 일종의 대항능을 갖게되며, 이런 생존 능력은 복잡한 유전적 유도현상 결과로 해석된다. Salmonella 있어서 ATR은 RpoS 의존적 그리고 RpoS 비의존적 현상으로 구분되며, 특히 혐기적 조건(5% $CO_2$, 5% H$_2$, 90% $N_2$)에서 rpoS$\Omega$Ap는 UK1과 동일한 ATR을 나타내어, 혐기적 조건의 ATR은 RpoS 비의존적인 것으로 판명되었다. P22와 MudJ (Km, lacZ)를 이용한 gene fusion기법과 sodium acetate (pH4.5)를 이용한 돌연변이체 분리방법을 병행하여 산민감성의 형질을 나타내는 LE487 aatA::MudJ를 얻었다. antA 는 Salmonella의 유전자 지도상에서 12min에 위치하는 것으로 조사되었다. antA는 혐기적 조건(5% $CO_2$, 5% H$_2$, 90% $N_2$)하의 pH4.3 조건에서 야생형 Salmonella 비해서 매우 높은 산민감성을 보여주었다. 그러므로 antA는 혐기적 ATR에 있어서 산적응 기전에 관여하는 중요한 유전자로 확인되었다.