• 한국미생물·생명공학회지
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• 제39권1호
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• pp.9-19
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• 2011

Bacillus subtilis의 pyrimidine biosynthetic (pyr) operon은 UMP의 de nove 생합성에 관여하는 enzyme들을 encode할 뿐만 아니라, 조절단백질인 PyrR도 encode한다. PyrR은 pyr mRNA-binding 조절 기능과 uracil phosphoribosyltransferase activity를 동시에 가지는 bifunctional 단백질이다. 본 연구에서는 Proteomic analysis를 이용하여 Uracil - 환경에서 DB104${\Delta}$pyrR의 단백질 패턴을 분석하여 단백질 레벨에서 PyrR 단백질의 실질적인 조절 양상을 관찰하였다. 두 균주의 세포질 단백질은 다양한 발현의 차이를 보였으며, Silver 염색된 2D-gel의 pI 4~10 사이에서는 1,300여개의 단백질이 검출되었으며, 단백질 발현 차이를 보이는 172개의 spot 중에서 42개의 단백질이 identification 되었다. 그 결과 pyr operon의 단백질(PyrAa, PyrAb, PyrB, PyrC, PyrD, and PyrF)이 모두 Up regulation이 이루어지고 있음을 확인할 수 있었으며, 이것은 단백질 레벨에서 Pyrimidine 생합성 과정이 PyrR에 의해서 정확히 Regulation 되어짐을 확인할 수 있었다. 또한 Pyrimidine 생합성의 Up regulation과 Down regulation 상태의 단백질의 패턴 양상도 분석할 수 있게 되었다. Pyrimidine의 생합성 과정은 DNA를 구성하는 기본적인 구성 요소를 생산하는 과정으로서 여러가지 Metabolism 가운데 중요한 위치를 차지하고 있다. 만약 Pyrimidine의 생합성 과정이 Over- expression된다면 다른 Metabolism의 균형에도 변화가 올 것이다. Proteomics Analysis에 이용한 DB104${\Delta}$pyrR 균주는 Pyrimidine 생합성의 조절에 관여하는 PyrR knock out 균주로서 Uracil - 환경에서는 전체적인 Pyrimidine 생합성 조절이 Up regulation이 되어지므로 Up regulation 동안 어떤 Metabolism에 영향을 주는지 관찰을 할 수 있게 되었다. 특히 Amino Acid Metabolism에 관계있는 단백질의 Up regulation이 이루어짐을 관찰할 수 있었으며 이것은 현재 각광을 받고 있는 단백질 산업에 응용함으로써 산업적으로 많은 기대를 할 수 있을 것으로 예상되어진다.

• 미생물학회지
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• 제44권3호
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• pp.264-269
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• 2008

$\beta$-Amylase를 생산하여 전분 분해능을 갖는 산업용 효모를 개발하기 위해 산업용 Saccharomyces cerevisiae에서 Achlya bisexualis $\beta$-amylase (BAMY)유전자를 ADC1 promoter에 연결하여 구성적으로 발현시켰다. 효모의 형질전환은 $\delta$-서열을 재조합 부위로 하는integration 시스템을 이용하였다. Integration 시스템의 세균 유전자 부분은 제거되고 BAMY 유전자와 $\delta$-서열을 갖고 있는 짧은integrative cassette를 제조하였다. BAMY 유전자를 발현하는 재조합 S. cerevisiae 형질전환체는 세포외 배지로 45 kDa의 $\beta$-amylase를 분비하였고, $\beta$-amylase 활성은 A. bisexualis에 비해 약 18.5배 높았다. 형질전환체에 다중도입된 BAMY 유전자는 비선택배지에서 100세대 생장 후에도 안정되게 유지되었다. 각종전분을 기질로 했을 매 $\beta$-amylase의 활성은soluble starch를 기질로 했을 경우와 유사하게 높았고, 가수분해산물 분석 결과 maltose가 주 분해산물이었다.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1197-1206
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• 2005

Vibrio vulnificus is an opportunistic pathogen that causes a septicemia and expresses numerous virulence factors, in which luxS and smcR are genes encoding for components responsible for quorum-sensing regulation. In the present study, null mutants were constructed with lesions in each or both of these two genes from the V. vulnificus Vv$\Delta$Z strain, which is a lacZ$^{-}$ and chloramphenicol/streptomycin-resistant derivative of the wild-type ATCC29307 strain, and their phenotypes related to virulence were compared with those of the parental cells. $LD_{50}$ and histopathological findings of luxS-, smcR-, or luxS- smcR- deficient mutant were not different from those of the parent strain, a lacZ-deficient streptomycin-resistant strain in mice. However, time of death in mice was delayed, and numbers of bacteria survived in bloodstream after intraperitoneal injection in mice were decreased by mutation, especially luxS and smcR double mutant (VvSR$\Delta$ZSR). These phenomena were supported by increased serum sensitivity and delayed bacterial proliferation in both murine blood and iron-restricted medium. These results suggest that the luxS and luxR homologous genes in V. vulnificus could playa role in bacterial survival in host by enhancing proliferation and adjusting to changed environment.

• 한국미생물·생명공학회지
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• 제30권3호
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• pp.230-234
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• 2002

모기 살충성 Bacillus thuringiensis subspangiensis 21-2균주의 용혈성 내독소 단백질의 특성을 검토하고자 21-2균주의 용혈성을 가진 유전자를 Escherichia coli HBIO쎄 형질전환시켰다. 이들 중에서 형질전환 균주 47은 독소 단백질을 생산하며 2.5 kb DNA을 함유한다는 것을 효소항체법, immunoblot및 DNA전기영동법으로 확인하였다. 또한, 형질전환 균주 47-5는 2.5 kb DNA를 다시 Hind ll견 절단하여 pUC118 연결시켜서 조제하였다 그 결과형질전환 균주 47-5은 1.Bkb DNA를 함유하며, 23 kD꺼 독소 단백질을 발현하고, 발현된 독소 단백질은 Aedes aegypti모기 유충에 독성을 나타내었다. 또한 23 kDa의 내독소 단백질 그 자체로는 사람의 적혈구를 용해하지 못하였으나, proteinase K로 처리한 후에는 적혈구에 대해 용혈성을 나타내었다.

• Journal of Microbiology
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• 제41권2호
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• pp.121-128
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• 2003

The identification of genes involved in true hypha formation is important in the study of mechanisms underlying the morphogenetic switch in yeast. We isolated a gene responsible for the morphogenetic switch in Yarrowia lipolytica, which forms true hyphae in response to serum or N-acetylglucosamine. The isolated gene, encoding 847 amino acids, had sequence identities of 27% and 25% with the Bud6 (Aip3) proteins of Saccharomyces cerevisiae and Schizosaccharomyces pombe, respectively. Disruption of this gene, designated YIBUD6, in haploid and diploid strains significantly reduced the ability of Y. lipolytica to switch from the yeast form to the hyphal form in hypha-inducing media. It was also found that YIBud6$\Delta$ mutants were rounder than the wild type when grown in the yeast form. These results indicate that the YIBud6 protein is necessary for hyphal growth and cell polarity in both haploid and diploid Y. lipolytica cells.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2000년도 International Meeting 2000
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• pp.58-65
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• 2000

Diarrheal diseases are a major cause of both illness and death in developing countries and are caused by rotavirus, Shigella spp., Salmonella spp., enterotoxigenic Escherichia coli (ETEC), and Vibrio spp. In this study, for the development of vaccine against diarrheal diseases caused by Shigella sonei, Salmonella typhimurium, E. coli O157, and Vibrio cholerae, cloning and nucleotide sequence analysis of genes and characteristics of their gene products in E. coli were performed. For construction of attenuated strain of S. sonnei KNIH104 and Salmonella typhimurium KNIH100, the aroA genes were cloned, respectively. The recombinant plasmid $_pJP{\Delta}A45$ containing aroA deleted region and suicide vector $(_pJP5603)$ was constructed. The aroA gene deleted mutants were constructed using this recombinant plasmid. For cloning gene encoding antigenic region of E. coli O157 KNIH317, the O-antigen synthesis gene cluster and sit gene was cloned. The E. coli XL1-Blue cells harboring this recombinant plasmid showed cytotoxicity in Vero cells. The ctx gene was cloned for tile purpose of antigenic region against V. cholerae KNIH002. Sequence analysis confirmed that the virulence gene cassette was consisted of ace, zot, ctxA and ctxB genes.

• The Plant Pathology Journal
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• 제27권1호
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• pp.20-25
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• 2011

Gibberella zeae (anamorph: Fusarium graminearum), a homothallic (self-ferile) ascomycete with ubiquitous geographic distribution, causes serious diseases in several cereal crops. Ascospores (sexual spores) produced by this fungal pathogen have been suggested as the main source of primary inoculum in disease development. Here, we report the function of a gene designated GzRUM1, which is essential for ascospore formation in G. zeae. The deduced product of GzRUM1 showed significant similarities to the human retinoblastoma (tumor suppressor) binding protein 2 and a transcriptional repressor, Rum1 in the corn smut fungus (Ustilago maydis). The transcript of GzRUM1 was detected during the both vegetative and sexual stages, but was more highly accumulated during the latter stage. In addition, no GzRUM1 transcript was detected in a G. zeae strain lacking a mating-type gene (MAT1-2), a master regulator for sexual development in G. zeae. Targeted deletion of GzRUM1 caused no dramatic changes in several traits except ascospore formation. The ${\Delta}$GzRUM1 strain produced perithecia (sexual fruit bodies) but not asci nor ascospores within them. This specific defect leading to an arrest in ascospore development suggests that GzRUM1, as Rum1 in U. maydis, functions as a transcriptional regulator during sexual reproduction in G. zeae.

• Journal of Microbiology and Biotechnology
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• 제29권4호
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• pp.596-606
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• 2019

N-acyl-homoserine lactone quorum sensing (AHL-QS) has been shown to regulate many physiological behaviors in Serratia marcescens MG1. In the current study, the effects of AHL-QS on the biosynthesis of acid and neutral products by S. marcescens MG1 and its isogenic ${\Delta}swrI$ with or without supplementing exogenous N-hexanoyl-L-homoserine lactone ($C_6-HSL$) were systematically investigated. The results showed that swrI disruption resulted in rapid pH drops from 7.0 to 4.8, which could be restored to wild type by supplementing $C_6-HSL$. Furthermore, fermentation product analysis indicated that ${\Delta}swrI$ could lead to obvious accumulation for acidogenesis products such as lactic acid and succinic acid, especially excess acetic acid (2.27 g/l) produced at the early stage of fermentation, whereas solventogenesis products by ${\Delta}swrI$ appeared to noticeably decrease by an approximate 30% for acetoin during 32-48 h and by an approximate 20% for 2,3-butanediol during 24-40 h, when compared to those by wild type. Interestingly, the excess acetic acid produced could be removed in an AHL-QS-independent manner. Subsequently, quantitative real-time PCR was used to determine the mRNA expression levels of genes responsible for acidogenesis and solventogenesis and showed consistent results with those of product synthesis. Finally, by close examination of promoter regions of the analyzed genes, four putative luxI box-like motifs were found upstream of genes encoding acetyl-CoA synthase, lactate dehydrogenase, ${\alpha}$-acetolactate decarboxylase, and Lys-like regulator. The information from this study provides a novel insight into the roles played by AHL-QS in switching from acidogenesis to solventogenesis in S. marcescens MG1.

• Journal of Microbiology and Biotechnology
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• 제29권8호
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• pp.1299-1309
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• 2019

As an opportunistic bacterial pathogen, Pseudomonas aeruginosa PAO1 contains two phenazine-producing gene operons, phzA1B1C1D1E1F1G1 (phz1) and phzA2B2C2D2E2F2G2 (phz2), each of which is independently capable of encoding all enzymes for biosynthesizing phenazines, including phenazine-1-carboxylic acid and its derivatives. Other previous study reported that the RpoS-deficient mutant SS24 overproduced pyocyanin, a derivative of phenazine-1-carboxylic acid. However, it is not known how RpoS mediates the expression of two phz operons and regulates pyocyanin biosynthesis in detail. In this study, with deletion of the rpoS gene in the $PA{\Delta}phz1$ mutant and the $PA{\Delta}phz2$ mutant respectively, we demonstrated that RpoS exerted opposite regulatory roles on the expression of the phz1and phz2 operons. We also confirmed that the phz1 operon played a critical role and especially biosynthesized much more phenazines than the phz2 operon when the rpoS gene was knocked out in P. aeruginosa. By constructing the translational reporter fusion vector lasR'-'lacZ and the chromosomal fusion mutant $PA{\Delta}lasR::lacZ$, we verified that RpoS deficiency caused increased expression of lasR, a transcription regulator gene in a first quorum sensing system (las) that activates overexpression of the phz1 operon, suggesting that in the absence of RpoS, LasR might act as an intermediate in overproduction of phenazine biosynthesis mediated by the phz1 operon in P. aeruginosa.

• Journal of Photoscience
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• 제9권2호
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• pp.37-40
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• 2002

Ascidians are lower chordates, and their tadpole-like larvae share a basic body plan with vertebrates. To study photoreceptive systems in ascidians, we have isolated and characterized cDNA clones for three opsins, five G protein ${\alpha}$ subunits (G${\alpha}$), catalytic and regulatory subunits of cGMP phosphodiesterase (PDE), and arrestin from the ascidian Ciona intestinalis tadpole larva. Ci-opsin1 and Ci-opsin2 are vertebrate-type opsins, while Ci-opsin3 is a retinal photoisomerase similar to retinochrome and mammalian RGR. Both Ci-opsin1 and arrestin are specifically localized in the photoreceptor cells of the ocellus, whereas Ci -opsin2 is not expressed in the photoreceptors, but is co-localized in another population of neurons in the brain with PDE (Ci-PDE9 and Ci-PDE$\delta$). Ci-opsin3 is present in the entire region of the brain. Though five different cDNAs encoding Ga have been cloned, no transducin-type G protein has been found yet. Interestingly, one of G${\alpha}$i isoform is conspicuously expressed in the entire region of the brain. The Ci-opsin3 gene expression was observed in a broad area of the brain vesicle as well as in the visceral ganglion. Genes encoding ascidian homologs of CRALBP and ${\beta}$-CD, whose function is required for the mammalian visual cycle, are co-expressed with Ci-opsin3 in the brain vesicle and visceral ganglion. Localization of Ci-opsin3, CRALBP, and ${\beta}$-CD in a broad area of the brain suggests that the brain of the ascidian larva has a visual cycle system similar to that of the vertebrate RPE. Based on these data, we discuss the evolution of vertebrate visual systems.