• 자연과학논문집
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• 제10권1호
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• pp.33-37
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• 1998

식물의 주요 phytohormone의 하나인 cytokinin은 식물체의 줄기와 뿌리성장 그 외에도 영양의 전달이나 노화방지, 열매숙성 등 식물의 성장과 발달에 미치는 영향은 크고 다양하다. Cytokinin 생합성에 관여하는 효소를 생산하는 것으로 알려져 있으며 토양박테리아 Agrobacterium tumefaciens에 존재하는 유전자인 isopentenyl transferase (jpt)를 이용한 많은 분자생물학적 연구가 진행되어 왔는데 그 중 하나로 이 연구에서 jpt 유전자에 의한 cytokinin의 overproduction이 식물체에 성장과 발달에 어떠한 영향을 주는지 관찰하고 그 결과가 제시할 수 있는 작물의 유전 공학적 이용가능성에 대하여 알아본다.

• Journal of Microbiology
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• 제35권4호
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• pp.271-276
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• 1997

We isolated phenotypic suppressors of an absB (antibiotics synthesis suppression) strain. In the absB colonies, all four antibiotics including two pigmented antibiotics were blocked so that no pigmentation could be found. We assumed that in the colonies with the wuppressive(or reversive) mutation, both pigmentation would be restored so that the strains with suppressive mutation could be cisually detected. Harvested absB spores were treated with chemical mutagen along with electric shock, and were spread on specially fromulated minimal medium plates. The pigmented colonies were isolated from the unpigmented majorities. In one candidate strain, the restoration and significant overproduction of actinorhodin and undecylprodigiosin were recognized. In three other candidate strains, the overproduction of actinorhodin and restoraion of undecylprodigiosin were observed. The production of the two unpigmented antibiotics (CDA and methylenomycin) were visualized in the tested candidate strains. The strains with wuppressive mutations would be very useful in dlucidating the regulation network of antiviotics synthesis and overproduction of the antibiotics.

• Journal of Microbiology and Biotechnology
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• 제12권5호
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• pp.753-759
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• 2002

$\beta$-Cyclodextrin glucanotransferase ($\beta$-CGTase) was overproduced extracellularly using recombinant E. coli by transforming the plasmid pECGT harboring a secretive signal peptide. The $\beta$-CGTase gene of alkalophilic Bacillus firmus var alkalophilus was inserted into the high expression vector pET20b(+) containing a secretive pelB signal peptide, and then transformed into E. coli BL2l(DE3)pLysS. The optimum culture conditions fer the overproduction of $\beta$-CGTase were determined to be TB medium containing 0.5% (w/v) soluble starch at post-induction temperature of $25^{\circ}C$. A significant amount of $\beta$-CGTase, up to 5.83 U/ml, which was nine times higher than that in the parent strain B. firmus var. alkalophilus, was overproduced in the extracellular compartment. A pH-stat fed-batch cultivation of the recombinant E. coli was also performed to achieve the secretive overproduction of $\beta$-CGTase at a high cell density, resulting in production of up to 21.6 U/ml of $\beta$-CGTase.

• Journal of Microbiology and Biotechnology
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• 제5권1호
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• pp.18-21
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• 1995

Endoglucanase gene of Pseudomonas sp. LBC505 was previously cloned in pUCl9 to yield plasmid pLC1. overproduction of endoglucanase was attempted by following ways. First, the endoglucanase gene of Pseudomonas sp. LBC505 cloned in pUCl9(pLC1) was tandemly inserted, step by step, into a expression vector pKK223-3 in a directly repeated form to enhance productivity of endoglucanase. Escherichia coli containing pKCC30 among the resulting plasm ids showed the higher yield of the endoglucanase. Ecoli harboring pKCC30 which had three inserted endoglucanase genes expressed about 12.3 times as much CMCase activity as Ecoli harboring pLCl. Second, the endoglucanase gene was subcloned into Bacillus subtilis expression vector pgnt41 for both overproduction and extracellular secretion of the endoglucanase. A resulting plasmid pgntc15 in Bacillus subtilis expressed 4.3-fold higher levels of CMCase activity than that of E.coli harboring pLCl and the endoglucanase produced was entirely secreted into the culture medium.

• 한국잠사학회:학술대회논문집
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• 한국잠사학회 2003년도 International Symposium of Silkworm/Insect Biotechnology and Annual Meeting of Korea Society of Sericultural Science
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• pp.145-146
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• 2003

Overproduction of transforming growth factor (TGF)-$\beta$l has been implicated in the pathogenesis of fibrotic diseases. TGF-$\beta$l plays a crucial role in the accumulation of extracellular matrix (ECM) in human and experimental glomerular diseases. However, it remains unclear whether inhibition of TGF- $\beta$l overproduction would suppress TGF- $\beta$l induced ECM accumulation. To inhibit the overproduction of TGF- $\beta$l in experimental glomerulonephritis induced by anti-Thy 1.1 antibody, we introduced antisense oligodeoxynucleotides (ODN) fur TGF- $\beta$l into the nephritic kidney by the HVJ-liposome-mediated gene transfer method. (omitted)

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.82-85
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• 2005

Doxorubicin is a highly-valuable anthracycline-family polyketide drug with a very potent anticancer activity, typically produced by a Gram-positive soil bacterium called Streptomyces peucetius. Thanks to the recent development of Streptomyces genomics-based technologies, the random mutagenesis approach for Streptomyces strain improvement has been switched toward the genomics-based technologies including the application of DNA microarray systems. In order to identify and characterize the genomics-driven potential target genes critical for doxorubincin overproduction, three different types of doxorubicin overproducing strains, a dnrI(doxorubicin-specific positive regulatory gene)-overexpressor, a doxA (gene involved in the conversion from daunorubicin to doxorubicin)-overexpressor, and a recursively-mutated industrial strain, were generated and examined their genomic transcription profiles using Streptomyces DNA microarray systems. The DNA microarray results revealed several potential target genes in S. peucetius genome, whose expressions were significantly either up- or down-regulated comparing with the wild-type strain. A systematic understanding of doxorubicin overproduction at the genomic level presented in this research should lead us a rational design of molecular genetic strain improvement strategy.

• Journal of Microbiology and Biotechnology
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• 제8권2호
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• pp.141-145
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• 1998

Overproduction of intracellular ${\beta}$-glucosidase was attempted by modifying the promoter region of a ${\beta}$-glucosidase gene cloned from Cellulomonas fimi and expressing it in Bacillus subtilis DB 104. A strong engineered promoter, BJ27UΔ88, was fused to the ${\beta}$-glucosidase gene after removing its native promoter. An effective Shine-Dalgamo sequence (genel0 of phage T7) was inserted between the promoter and the ${\beta}$-glucosidase structural gene. The modified gene was overexpressed in B. subtilis and produced 1121.5 units of ${\beta}$-glucosidase per mg protein which is about $12\%$ of total intracellular protein. Secretion of overproduced intracellular ${\beta}$-glucosidase was attempted by using the signal sequence of the Bacillus endoglucanase gene as well as an in-frame hybrid protein of endoglucanase. The hybrid protein was normally secreted into the culture medium and still retained ${\beta}$-glucosidase activity.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.534-538
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• 2007

Avermectin and its analogs are major commercial antiparasitic agents in the fields of animal health, agriculture, and human infections. To increase our understanding about the genetic mechanism underlying avermectin overproduction, comparative transcriptomes were analyzed between the low producer S. avermitilis ATCC31267 and the high producer S. avermitilis ATCC31780 via a S. avermitilis whole genome chip. The comparative transcriptome analysis revealed that fifty S. avermitilis genes were expressed at least two-fold higher in S. avermitilis ATCC31780. In particular, all the avermectin biosynthetic genes, including polyketide synthase (PKS) genes and an avermectin pathway-specific regulatory gene, were less expressed in the low producer S. avermitilis ATCC31267. The present results imply that avermectin overproduction in S. avermitilis ATCC31780 could be attributed to the previously unidentified fifty genes reported here and increased transcription levels of avermectin PKS genes.

• 한국미생물·생명공학회지
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• 제21권6호
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• pp.615-621
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• 1993

In order to maximize the riboflavin production by a mutant strain Ashbya gosspyii, the optimization of medium and fed-batch fermentation were performed. As carbon sources, glucose and soybean oil were necessary for the riboflavin overproduction. Optimal concentrations of glucose and soybean oil in the flask cultures were found to be 3.0% and 0.5%, respectively, in a complex medium containing corn steep liquor(CLS) 1%. Among the various organic nitrogen sources tested, CSL was the most effective one both for the cell growth and riboflavin overproduction.

• Natural Product Sciences
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• 제13권4호
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• pp.322-327
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• 2007

Fresh Rehmanniae radix is known as a traditional medicine with anti-inflammatory and antioxidant activities. However, whether Rehmanniae radix attenuates autoimmune inflammation in lupus models characterized by T cell-dependent autoimmune disease including overproduction of proinflammatory cytokines, loss of T cell tolerance, and B cell hyperactivity remains unclear. We investigated the effect of fresh Rehmanniae radix methanol extracts (RGMeOH) on the in vitro overproduction of proinflammatory cytokines by immune cells from pristaneinduced lupus BALB/c mice. These results showed that RGMeOH remarkably attenuated Con A-increased overproduction of proinflammatory cytokines, such as IL-2, IFN-${\gamma}$, IL-6 and IL-10 by splenocytes from pristaneinduced lupus mice. RGMeOH greatly reduced LPS-induced production of TNF-${\alpha}$ by splenic macrophages from pristane-induced lupus mice, while significantly enhanced LPS-induced production of IL-10 but did not alter IL-6 by splenic macrophages and splenocytes. These findings suggest that RGMeOH may ameliorate lupus systemic inflammatory autoimmunity via down-regulation of TNF-${\alpha}$ and T cell-dependent cytokine production.