• Korean Journal of Microbiology
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• v.46 no.2
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• pp.113-121
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• 2010

Bacillus subtilis PhoP-PhoR two-component system (TCS) senses phosphate deficiency conditions, and then controls expression of the Pho regulon to prolong survival. The sensor histidine kinase, PhoR, is autophosphorylated and transfers the phosphate to the response regulator, PhoP. Phosphorylated PhoP (PhoP~P) binds to repeated 6-bp consensus PhoP binding sequences of Pho regulon promoters and activates or represses gene expression. Pho signal transduction systems are part of interconnected signal transduction network involving at least three TCSs (PhoP-PhoR, ResD-ResE TCS, SpoOA phosphorelay), a global carbon metabolism regulator (CcpA), and transition state regulators (AbrB, ScoC). In addition, PhoP-PhoR TCS is cross related with YycF-YycG TCS by cross-regulation. While indescribable progress has been made in understanding phosphate deficiency stress response through refined expression of the Pho regulon in the recent past years, many important questions still remain. Solving these questions may provide important information for application study using B. subtilis.

• Journal of Microbiology and Biotechnology
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• v.25 no.7
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• pp.1015-1025
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• 2015

The development of diverse polymyxin derivatives is needed to solve the toxicity and resistance problems of polymyxins. However, no platform has generated polymyxin derivatives by genetically engineering a polymyxin synthetase, which is a nonribosomal peptide synthetase. In this study, we present a two-step approach for the construction of engineered polymyxin synthetases by substituting the adenylation (A) domains of polymyxin A synthetase, which is encoded by the pmxABCDE gene cluster of Paenibacillus polymyxa E681. First, the seventh L-threonine-specific A-domain region in pmxA was substituted with the L-leucine-specific A-domain region obtained from P. polymyxa ATCC21830 to make polymyxin E synthetase, and then the sixth D-leucine-specific A-domain region (A_6-D-Leu-domain) was substituted with the D-phenylalanine-specific A-domain region (A_6-D-Phe-domain) obtained from P. polymyxa F4 to make polymyxin B synthetase. This step was performed in Escherichia coli on a pmxA-containing fosmid, using the lambda Red recombination system and the sacB gene as a counter-selectable marker. Next, the modified pmxA gene was fused to pmxBCDE on the chromosome of Bacillus subtilis BSK4dA, and the resulting recombinant strains BSK4-PB and BSK4-PE were confirmed to produce polymyxins B and E, respectively. We also succeeded in constructing the B. subtilis BSK4-PP strain, which produces polymyxin P, by singly substituting the A_6-D-Leu-domain with the A_6-D-Phe-domain. This is the first report in which polymyxin derivatives were generated by genetically engineering polymyxin synthetases. The two recombinant B. subtilis strains will be useful for improving the commercial production of polymyxins B and E, and they will facilitate the generation of novel polymyxin derivatives.

• International Commerce and Information Review
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• v.6 no.3
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• pp.63-79
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• 2004

Peer-to-peer(P2P) has potential strength and possible factors which enable it to develop toward a new business by supplementing the limitation of the existing central server-type network. In various business sectors, various attempts have already been made to apply P2P. The computing power which was possible to be formed through peer-to-peer networking will become a powerful tools for expanding toward new business area depending the utilization methods by sector. Although the technology-centric P2P concept is a major interest now, its development direction will head toward service-centric P2P concept for satisfying desires of end-users(individual peers) for reliable contents and improving their purchasing convenience. But the solution requisites should be solved for the efficient application of P2P to business such as the establishment of and supplement for the industrial standard and legal system for P2P, the enhancement of peers recognition of P2P. Presently e-commerce using P2P is being implemented by a few enterprises locally by means of B2C. But if many enterprises enter this type of e-commerce, and the standardization of peer programmes, goods and documents is made, it will be able to be extended to B2B. Also it seems that it can be utilized in international transactions as well as in domestic transactions. So there is much room for the application of P2P to be extended further. Also there has been presented the necessity for related industries to support their work with theories and for academic studies to be made actively to set the direction of its development. It is hoped that multi-angled and in-depth studies on the utilization of P2P and various attempts to application of it to business be made on the basis of this study. For the development of P2P, continuous study and attempts are needed. The field of P2Ps application is very large and it will become a powerful tool, depending upon its application methods.

• YAKHAK HOEJI
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• v.35 no.5
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• pp.394-400
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• 1991

A question whether abnormal responsiveness of hypothalamic catecholaminergic nervous system to ovarian steoid hormones in spontaneously hypertensive rats (SHR) exist was investigated. Four groups of experimental animals were prepared for SHR and normotensive Wistar rats (NW) respectively: 1) intact, 2) ovariectomized (OVX+V), 3) ovariectomized and estrogen treated (OVX+E), 4) ovariectomized and estrogen plus progesterone treated (OVX+E+P) groups. Hypothalami from experimental animals were dissected out and used for determination of .alpha.-adrenergic receptor binding characteristics and catecholamine contents. Norepinephrine(NE) content and B$_{max}$ of $\alpha_1$-adrenergic receptors in hypothalami were greater in intact SHR than in intact NW, but dopamine(DA) content was lower in SHR than in NW. Neither contents of NE and DA nor binding characteristics of $\alpha_1$-adrenergic receptors were different in OVX+V and OVX+E group from intact group of both SHR and NW. Kd and B$_{max}$ of $\alpha_1$-adrenergic receptors in OVX+E+P was lower than that in intact SHR but not in NW. DA content was lower in OVX+E+P than in intact group of SHR and NW. The result of the present study indicates that there is an abnormal responsiveness of hypothalamic catecholaminergic nervous system to ovarian steroid hormones in SHR which may be one of genetically-determined factors probably not responsible for the development of hypertension.

• Journal of Microbiology and Biotechnology
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• v.20 no.6
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• pp.1022-1026
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• 2010

The different cleavage patterns of pYBamy59 plasmid isolated from E. coli $DH5{\alpha}$ and B. longum MG1 by the cell extract of B. longum MG1 suggested that the main reason for its low transformation efficiency was related to the restriction modification (R-M) system. To confirm the correlation between the R-M system and transformation efficiency, in vitro methylation and site-directed mutagenesis were performed in pYBamy59. Sequence analysis of pYBamy59 fragments digested by the cell extract of B. longum MG1 revealed that all fragments were generated by restriction of the sequence recognized by SacII endonuclease. When pYBamy59 from E. coli was methylated in vitro by CpG or GpC methyltransferase, it was protected from SacII digestion. Site-directed mutagenesis, which removed SacII sites from pYBamy59, or in vitro methylation of pYBamy59 showed 8- to 15-fold increases in the transformation efficiency over intact pYBamy59. Modification of the SacII-related R-M system in B. longum MG1 and in vitro methylation in pYBamy 59 can improve the transformation efficiency in this strain. The results showed that the R-M system is a factor to limit introduction of exogenous DNA, and in vitro modification is a convenient method to overcome the barrier of the R-M system for transformation.

• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.2153-2156
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• 2002

인터넷의 보급이 확산되고 진자문서 데이터 포맷으로 XML의 효용성에 대한 인식이 높아지면서 기업간 진자상거래를 위한 EDI 분야에서도 전통적인 EDI 방식의 한계점을 극복하고 인터넷 기반의 전자상거래 모델 개발을 위해서 XML/EDI 및 ebXML에 대한 관심이 높아지고 있다. 따라서, 본 논문에서는 유통 업종의 업무 프로세스를 분석하여 ebXML BPSS 기반으로 업무 프로세스를 정의하고, 기존의 UN/EDIFACT 문서와 호환될 수 있는 XML/EDI 전자문서를 개발하였다. 그리고 중계서비스를 거치지 않고 거래 파트너간에 전자상거래 데이터 교환이 가능한 XML/EDI 시스템을 설계 및 구현하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.6
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• pp.401-406
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• 2018

In this paper, we present E-band bond-wire modeling and a matching network to compensate for the effect of the bond-wire. The impedance of the bond-wires is extracted using three-dimensional electromagnetic simulation. The matching network was designed using a simple structure. The implemented matching network was verified with a commercial 71~81 GHz LNA IC and an interconnection based on the WR-12 waveguide. The matching network increases the transmission coefficient of the system by up to 4.5 dB, power gain by up to 3.12 dB, $P_{1dB}$ by up to 2.2 dB, and improves the gain flatness by ${\pm}1.07dB$.

• KSBB Journal
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• v.15 no.4
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• pp.331-336
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• 2000

The antimutagenic activity of the extract of Artemisia capillaris THUNB on the mutagenicity induced by benzo(a)pyrene [B(a)P] in the presense of S9 mixture was studied using bacterial mutagenic assay system. Samples harvested in summer and autumn were extracted using ethanol and hot water. Among these extracts the water extract of summer sample had the strongest inhibitory effect against the mutagenenicity of B(a)P, The water extract of Artemisia capillaris THUNB was separated again into ethanol soluble and insoluble parts. The ethanol insoluble part(El) of water extract exhibited higher inhibition effects than the ethanol soluble part against the mutagenic activity of B(a)P. El showed dose-dependent activity on the mutagenicity of B(a)P in SOS Chromotest and Ames test. The 50% inbibition concentraction $(IC_{50}$ of El were $200{\mu}g/assay$ $600{\mu}g/plate$ and $800{\mu}b/plate$ in E. coil PQ37 S. typhimurium TA100 and TA98 respectively. El were showed desmutagenic effect but had no effect on the DNA repair system for B(a)P-induced mutagenesis. HPLC analysis showed that the formation of aflatoxin M1 by cytochrome P-450 1A1 known as playing an impotant role on B(a) P-induced mutagenicity was highly inhibited by El. Therefore we encluded that B(a)P-induced mutagencity can be reduced possible due to the interference of el with cytochrome P-450 1A1-dependent bioactivation.

• Communications of the Korean Mathematical Society
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• v.15 no.1
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• pp.59-69
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• 2000

For a permutation ${\mu}$ in S$\sub$b/, the limit algebra A${\mu}$ of the stationary system given by ${\mu}$ is isomorphic to a refinement limit algebra if and only if its exponent set E(${\mu}$) is the set {0}. In the current paper, we prove a sufficient condition under which E(${\mu}$)={0} when the order of ${\mu}$ is a power of p, where p is a prime number dividing b.

• KSBB Journal
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• v.23 no.5
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• pp.445-448
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• 2008

Candida antarctica lipase B (CalB) is an efficient biocatalyst for many organic synthesis reactions. To make full use of CalB, we need effective expression system. Previously recombinant CalB was successfully expressed in the methylotropic yeast Pichia pastoris. In addition, we succeed in the functional expression of CalB in the Escherichia coli cytoplasm. This CalB expression system in E.coli has many considerable advantages in comparison with other expression systems and enables high-throughput screening of gene libraries as those derived from directed evolution experiments. To optimize E.coli system, we investigate comparing between OrigamiB (DE3) and BL21 (DE3) and observing effect of IPTG amount.