• 미생물학회지
• /
• 제31권1호
• /
• pp.27-36
• /
• 1993

Rhizobium fredii USDA191 은 대기 중의 질소를 환원하여 식물체의 생육에 필요한 질소원을 공급해주는 세균으로 다량의 체외 다당류를 합성한다. 전위요소 Tn5의 삽입에 의한 돌연변이 유도로 다당류결핍 변이주 R. fredii YKL293 가 분리되었으며 이 변이주로부터 Tn5 에 인접한 DNA 단편이 pUC19 에 클로닝되었고(plyk5293),이 DNA 단편을 탐침으로 하여 .lambda.NM1149 에 구성되 USDA191 genomic library 로부터 야생형체외다당류 합성관련 유전자(exo) 를 함유한 클론 .lambda. NM1149 22E 를 plaque 혼성화에 의하여 분리하였다. 클론 NM1149.22E 에 들어있는 exo 유전자를 pBR322 에 옮겨서 pJW33을 만들고, 재조합체 pJW33 을 Escherichia coli POII734 에 도입시켜 lacZ 구조유전자를 함유한 MudI 1734 가 exo 유전자의 프러모토와 융합되어 lacZ 구조유전자의 전사가 이루어지도록 하였다. 위와 같이 만들어진 재조합체 플라스미드 pUM21을 함유한 E. coli JM83 은 .betha.-galactosidase 를 합성하였으며, 야생형 tacZ 유전자를 갖고 있는 E. coli LE392 에 비해서 14-25배 정도 낮은 역가를 보였다.

• 수산해양교육연구
• /
• 제28권4호
• /
• pp.947-956
• /
• 2016

This study analysed the documents of Sea Area Utilization Consultation of JongChun and ApHae located in West Coast of Korea and NaJeong located in East Coast of Korea in order to find out problems of site surveys and numerical simulations for coastal erosion projects of ocean physics, and suggested the improvement way to go. Current especially like wave-induced current is the one of the important external forces to handle coastal erosion but underestimated in the west coast. In case of east coast the various tests including wave-induced current were conducted but less efficient to find out the reasons of coastal erosion. The stiffness structure to protect coastal line like beach made the secondary erosion by using them without sufficient analysis for the erosion. In order to consult a Sea Area Utilization Consultation those are needed to review the scenarios for external forces such as wave and tidal currents, the site surveys for external forces, the net sediment analysis for years, the long periods of monitoring, and the guide line and revision of the rule for coastal erosion.

• International Journal of Fluid Machinery and Systems
• /
• 제5권4호
• /
• pp.174-179
• /
• 2012

A numerical study to investigate the effect of intake vortex occurrence on the performance of an axial hydraulic turbine for generating tidal power energy in Sihwa-lake tidal power plant, Korea, is performed. Numerical analysis of the flow through an sxial hydraulic turbine is carried out by solving three-dimensional Reynolds-averaged Navier-Stokes dquations with the shear stress transport turbulence model. In the real turbine operation, the vortex flows are occurred in both the side corners around the intake of an axial hydraulic turbine due to the interaction between the inflow angle of water and intake structure. To analyze these vortex phenomena and to evaluate their impacts on the turbine performance, the internal flow fields of the axial hydraulic turbines with the different inflow angles are compared with their performances. As the results of numerical analysis, the vortex flows do not directly affect the turbine performance.

• Archives of Pharmacal Research
• /
• 제16권4호
• /
• pp.271-275
• /
• 1993

In order to prepare a novel human insulin analogue suhbstituted with homoserine at B$^{30}$ / position, (B$^{30}$ /-homoserine) human insulin, a synthetic gene was designed by linking directly a gene for B chain with that for A chain. This gene was constructed by enzymatic joining of 10 different synthetic oligonucleotides, and then inserted at the polylinker region of pUC19 plasmid. To achieve a high level of gene expression, the gene fusion technique region of pUC19 plasmid. To achieve a high level of gene expression, the gene fusion technique was employed using amino terminal regions of lacZ gene up to Clal or hpal, and either of them has been located under tac promoter. The chemical induction of these fused genes by isopropyl-.betha.-D-thiogalactopyranoside (IPTG) gave a satisfactory level of expression in Escherichia coli harboring the ocnstructed plasmids. It was observed that the fused gene product as a single chain insulin precusor was produced more than 30% of total cell protein of E. coli as a form of inclusion body.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제3권1호
• /
• pp.11-14
• /
• 1998

A toluene-oxidizing strain of Pseudomanas mendocina KR1 containing toluene-4-mono-oxygenase (TMO) completely degrades TCE with the addition of toluene as a co-substrate in aerobic condition. In order to construct in situ bioremediation system for TCE degradation without any growth-stimulating nutrients or toxic inducer such as toluene, we used the carbon-starvation promoter of Pseudomonas putida MK1 (Kim, Y. et al., J. bacteriol., 1995). Upon entry into the stationary phase due to the deprivation of nutrients, this promoter is strongly induced without further cell growth. The TMO gene cluster (4.5 kb) was spliced downstream of the carbon starvation promoter of Pseudomonas putida MK1, already cloned in pUC19. TMO under the carbon starvation promoter was not expressed in E. coli cells either in stationary phase or exponential phase. For TMO expression in Pseudomonas strains, tmo and carbon starvation promoter region were recloned into a modified broad-host range vector pMMB67HES which was made from pMMB67HE(8.9 kb) by deletion of tac promoter and lacIq (about 1.5 kb). Indigo was produced by TMO under the carbon starvation promoter in a Pseudomonas strain of post-exponential phase on M9 (0.2% glucose and 1mM indole) or LB. 18% of TCE was degraded in 14 hours after entering the stationary phase at the initial concentration of 6.6 ${\mu}$M in liquid phase.

• Journal of Microbiology and Biotechnology
• /
• 제9권5호
• /
• pp.613-618
• /
• 1999

L-Proline-producing mutant strains were developed by exposing L-glutamic acid-producing bacteria to N-metyl-N-nitro-nitrosoguanidine and UV irradiation. A L-histidine auxotroph of Corynebacterium acetoacidophilum RYU3161(KCTC 0616BP), which was resistant to sulfaguanidine and proline analogs (DHP, AZC, TAC), was isolated. The activity of the mutant strain's $\gamma$-glutamyl kinase was 45% higher than that of the parent strain. The optimum level of L-histidine for production of L-proline was 0.16 g/l. In a 5-1 jar fermenter, the mutant strain produced L-proline at a high concentration (35 g/l) level within 48 h of cultivation.

• Journal of Microbiology
• /
• 제33권3호
• /
• pp.201-207
• /
• 1995

We have previously reported that SPP2 gene product of yeast Saccharomyces cerevisiae is involved in the pre-mRNA splicing. To investigate the rol ein the splicing pathway of the Spp2p protein, the SPP2 gene was overexpressed in Escherichia coli and polyclonal antibodies to Spp2p were generated from rabbits. First, a DNA fragment containing the SPP2 GENE without its promoter was subcloned into an E. coli expression vector, pKK233-3. The resulting recombinant plasmid pBQ14 contained an IPTG inducible tac promoter and the SPP2 structural gene. Overexpression of the SPP2 gene was achieved by additionof 0.1 to 1.0 mM IPTG to a logarithmic culture of E. coli JM103(pBQ14) for 90 min at 37.deg.C. Sequence of N-terminal 15 amino acids of the overproduced protein was well matched to the deduced one from the SPP2 reading frame. Then, polyclonal antibodies were generated from rabbits immunized with gel-purified SppSp protein. These antibodies reacted specifically with the Spp2p protein extracted from yeast cells expressing the SPP2 gene to a great extent. The antibodies could also block the activity of yeast splicing extracts.

• 한국화재소방학회논문지
• /
• 제23권6호
• /
• pp.91-97
• /
• 2009

본 연구에서는 현장실험결과를 바탕으로 모델링 해석을 통해 초고층건물에서 배연창이 가지는 배연성능의 경향성을 분석 및 평가하였다. 분석건물은 현장실험 대상건물인 40층 건물 외에 동일한 구조의 80층 및 120층 규모의 초고층건물로서 외기온도 TAC 2.5% 조건에서 건물의 층수, 배연창 개방방식 및 외벽의 기밀도가 배연창의 배연성능에 미치는 영향을 공기유동해석 프로그램인 CONTAMW 모델링을 통해 정량화된 분석결과를 도출하였다.

• 수산해양교육연구
• /
• 제12권1호
• /
• pp.98-121
• /
• 2000

The Korean fishery encountered a difficulty situation, due to the new regime of the Exclusive Economic Zone (EEZ) and the decreasing fisheries resources in Korean waters. In addition, the coastal areas are deteriorated by industrial wastes, sewage, farming wastes and pollution from aquaculture. In this situation, it is necessary to study the TAC (total allowable catch) - based management system, the development of fishing gears and appropriate fishing methods for stock conservation, and the automation system of fishing gears for improving the efficiency of fisheries. The objective of this study is to look for an appropriate system in marine production and resource management under the new UNCLOS (United National Convention for the Law of the Sea) regime for subjects in fishing gears and methods, production system, and information, and fisheries resources management. The results of this study could be used as scientific information to maintain and develop the Korean fisheries and to establish fisheries policy for the management of fisheries resources in Korean waters.

• 한국미생물·생명공학회지
• /
• 제47권2호
• /
• pp.242-249
• /
• 2019

Biosynthesis of indole-3-acetate (IAA) from L-tryptophan via indole-3-pyruvate pathway requires three enzymes including aminotransferase, indole-3-pyruvate decarboxylase, and indole-3-acetate dehydrogenase. To establish a bio-based production of IAA, the aspC, ipdC, and iad1 from Escherichia coli, Enterobacter cloacae, and Ustilago maydis, respectively, were expressed under control of the tac, ilvC, and sod promoters in C. glutamicum. Cells harboring ipdC produced tryptophol, indicating that the ipdC product is functional in this host. Analyses of SDS-PAGE and enzyme activity revealed that genes encoding AspC and Iad1 were efficiently expressed from the sod promoter, and their enzyme activities were 5.8 and 168.5 nmol/min/mg-protein, respectively. The final resulting strain expressing aspC, ipdC, and iad1 produced 2.3 g/l and 7.3 g/l of IAA from 10 g/l L-tryptophan, respectively, in flask cultures and a 5-L bioreactor.