• Korean Journal of Microbiology
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• v.45 no.4
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• pp.419-424
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• 2009

To provide the basis of biosensor based on the lux genes from bioluminescent bacteria of Photobacterium leiognathi and Vibrio harveyi, we test the expression of lux genes in several strains of Escherichia coli. The expression of the recombinant plasmid of PlXba.pT7-3, containing all lux genes requiring for light emission without adding substrate, in E. coli 43R was so strong to see the blue-green light in single colony as well as in the alginate immobilized cell. In addition, the light intensity was decreased by adding heavy metal ion such as cadmium and zinc ions. These result raise the possibility that a biosensor can be developed using the lux genes system.

• Journal of Life Science
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• v.31 no.1
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• pp.28-36
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• 2021

Edwardsiella piscicida is a significant cause of hemorrhagic septicemia in fish and gastrointestinal infections in humans. Survival bacteria require specialized mechanisms to adapt to environmental fluctuations. Hence, to understand the mechanism through which E. piscicida senses and responds to environmental osmolarity changes, we determined the protein expression profile and physiological properties under various salinity conditions in this study. The OmpR protein is a part of the Env-ZOmpR two-component system that has been implicated in sensing salt stress in bacteria. However, the physiological role played by this protein in E. piscicida remains to be elucidated. Therefore, in this work, the function of the OmpR protein in response to salt stress was investigated. Phenotypic analysis revealed that, in the mutant, three of the biochemical phenotypes were different from the wild type, including, citrate utilization, hydrogen sulfide, and indole production. Introduction of the plasmid containing the entire ompR gene to the mutant strain returned it to its parental phenotype. The retarded growth rate also partially recovered. Furthermore, in our studies, OmpR was not found to be related to cell motility. Taken together, our results from the mutational analysis, the growth assay, MALDI-TOF MS, qRT-PCR, and the phenotype studies suggest that the OmpR of E. piscicida is implicated in osmoregulation, growth, expression of porins (ETAE_1826), virulence-related genes (EseC, EseD and EvpC), and certain genes of unknown function (ETAE_1540 and ETAE_2706).

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.296-299
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• 2015

Cowpea mild mottle virus (CPMMV) has a wide range of hosts, such as the pea family and tomato. CPMMV is a non-reported virus in Korea, and is domestically designated as a controlled virus associated with plant quarantine. In this study, a rapid diagnostic method for the detection of CPMMV at quarantine sites was developed. For the development of a user-based system, the PCR compositions and conditions use existing methods of quarantine for the viruses. Two sets of RT-PCR and nested PCR were developed in this study that could be amplified from 579 → 298 dp and 638 → 252 bp, respectively. Furthermore, a sequence inserted positive control plasmid was developed, which is able to identify false-positives resulting from laboratory contamination. The findings of this study are important for the diagnosis of CPMMV in imported crops held in plant quarantine.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.64-64
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• 2012

아라미드는 일반적인 유기섬유와는 다른 우수한 역학적 성질을 바탕으로 보호의류 중에서 방탄방호 및 방검보호 의류에 사용되는 고부가 소재이다. 현재까지 ATY기계에서 사의 구조와 물성에 큰 영향을 미치는 Nozzle의 구조에 대한 연구결과는 많이 발표되어왔다. 그러나 최근 들어 소방방화방 검용 보호의류에 많이 사용되는 아라미드사에 ATY 공정 중에서 Nozzle의 직경이 ATY사의 물성에 어떤 영향을 미치는가에 대한 연구는 발표된 바가 없다. 따라서 본 연구에서는 Para-aramid/Nylon hybrid사를 이용하여 ATY로 제조할 경우, 표면에 생기는 loop로 인하여 타 소재와 접착시, 접착제 담지 성능이 향상되어 접착력이 상승되는 반면 아라미드 Hybrid사의 역학물성은 ATY가 가공되기 전의 물성보다 저하되는 약점을 가지고 있다. 따라서 본 연구에서는 ATY 제조공정에서 Nozzle의 직경을 달리할 때 Aramid/Nylon Hybrid ATY사의 물성변화를 분석함으로서 방화복과 방검용 보호의류에 적합한 아라미드 ATY사를 개발하고자 한다. 본 연구에서는 ATY 제조공정 중 다른 공정조건은 동일하게 하고 Nozzle의 직경을 0.6, 0.75, 1, 1.2mm로 변경하여 4가지 시료를 준비하고 물성분석을 위하여 제조된 시료의 강신도, 초기탄성률을 각각 측정하여 인장특성을 확인하였으며, 건열수축률과 습열수축률을 측정하여 시료의 열 수축률을 측정 분석하였다. 표면의 루프 발현 정도를 보기위하여 형태 불안정성을 측정 평가하였으며 영상현미경시스템을 사용하여 표면특성을 측정 평가하여 다음과 같은 결론을 얻었다. Nozzle의 직경이 증가함에 따라 절단강도는 30% 감소하였고 초기탄성률은 3배 가까이 감소하였다. 그리고 절단신도는 2배정도 증가하는 경향을 나타내었다. 또한 Nozzle의 직경이 증가함에 따라 ATY hybrid사의 건 습열수축률이 증가하다가 직경이 1.2mm일 때 감소하는 경향을 나타내었고 직경 변화에 따라 4~6%의 열 수축률의 분포를 보였다. Para-aramid/Nylon hybrid사의 형태불안정성은 0.3~0.5%를 분포를 나타내었고 Nozzle의 직경이 0.6, 1mm일 때 상대적으로 낮은 ATY의 불안정성이 확인되었다. Nozzle의 직경이 감소할수록 loop의 엉킴이 적으며 flat하였으며 직경이 1.2mm일 때 가장 조밀하고 표면에 loop가 많이 형성된 것을 확인하였다.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.185-192
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• 1998

Four kinds of polyamicacids(PAAs) were prepared by the condensation reaction of four diamines with different linkages, 3,3'-diaminodiphenyl sulfone(3,3'-$DDSO_2$), 4,4'-diaminodiphenyl sulfone(4,4'-$DDSO_2$), 4,4'-methylene dianiline(4,4'-MDA) and 4,4'-oxydianiline(4,4'-ODA), and dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride (BTDA) using the solvent, dimethylacetamide(DMAc). These four PAAs were blended with poly[2,2-(m-phenylene)-5,5'-bibenzimidazole](PBI) from the solution blending. Then called as Blend-I, II, III, and IV, respectively. Cast films or precipitated powders of the PBI/PAA blends were cured at a higher temperature than expected Tg to transform into PBI/PIs blends. Miscibility, specific intermolecular interaction for miscibility and their relative strength as a function of polyimide chemical structure with different four diamines in the PBI/PI systems were investigated. Four blends used in this study were all miscible, and the specific intermolecular interactions existing in these blends was thought to be the hydrogen bonding between the N-H of PBI and the C=O of PIs. The hydrogen bonding in the blends were shown to be stronger in the Blend-III and Blend-IV than Blend-I and II. It is speculated that the differences of hydrogen bonding strength of PBI/PI blends are dependent upon chemical structures of PIs, that is, PIs consisting of $SO_2$ group have a weaker hydrogen bonding strength than those of O or $CH_2$ group because the former has a larger spacer than the latter.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.132-142
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• 2014

In this paper, we propose a traffic lights detection method using visual attention and spot-lights detection. To detect traffic lights in city streets at day and night time, the proposed method is used the structural form of a traffic lights such as colors, intensity, shape, textures. In general, traffic lights are installed at a position to increase the visibility of the drivers. The proposed method detects the candidate traffic lights regions using the top-down visual saliency model and spot-lights detect models. The visual saliency and spot-lights regions are positions of its difference from the neighboring locations in multiple features and multiple scales. For detecting traffic lights, by not using a color thresholding method, the proposed method can be applied to urban environments of variety changes in illumination and night times.

• KSBB Journal
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• v.20 no.2 s.91
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• pp.112-115
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• 2005

E. coli in combination with bacteriophage $\lambda$ was used to overcome the intrinsic plasmid instability that is frequently found in recombinant fermentation especially in long-term operation. In order to enhance the stability and productivity, the bacteriophage ${\lambda}NM1070$ was used in this study. It is a $\lambda$ mutant, which is deficient in the synthesis of protein related to DNA packaging and cell lysis. The ${\lambda}NM1070$ is also a temperature-sensitive mutant. To optimize the production of recombinant protein in this temperature-sensitive system, the temperature effects on growth and cloned gene expression were investigated for stable and efficient recombinant gene expression. The induction to the lytic state was not complete at $36^{\circ}C$ while the temperature above $40^{\circ}C$ induced the lytic state completely. However, the productivity was decreased at $42^{\circ}C$ by temperature inhibition. The L-free cell concentration increased with the increase of temperature until $40^{\circ}C$. In conclusion, ${\lambda}NM1070$ has the optimal temperature at $38^{\circ}C$ for stability and at $40^{\circ}C$ for expression.

• Journal of Life Science
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• v.25 no.6
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• pp.631-637
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• 2015

Streptavidin, a protein produced by Streptomyces avidinii, strongly binds up to four molecules of vitamin H, d-biotin exhibiting the dissociation constant of about 10⁻¹⁵ M. This strong binding affinity has been applied for detection and characterization of numerous biological molecules suggesting expression and purification of functional streptavidin should be very useful for the application of this streptavidin-biotin interaction. To express a soluble streptavidin in Escherichia coli, We synthesized streptavidin genes and cloned into pET-22b plasmid, which uses T7 RNA polymerase/T7 promoter expression systems containing pelB leader for secretion into periplasmic space and six polyhistidine tags at C-terminus for purification of expressed proteins. Although streptavidin is toxic to Escherichia coli due to strong biotin binding property, streptavidin was expressed very sufficiently in a range of 10-20 mg/ml. In SDS-PAGE, the size of purified protein was shown as 17 kDa in denatured condition (boiling) and 68 kDa in native condition (without boiling) suggesting tetramerization of monomeric subunit by non-covalent association. Further analysis by size-exclusion chromatography supported streptavidin’s tetrameric structure as well. In addition, soluble streptavidin detected biotinylated proteins in westernblot indicating its functional activity to biotin. Taken these results together, it concluded that our simple expression system was able to show high yield, homotetrameric formation and biotin binding activity analogous to natural streptavidin.

• Polymer(Korea)
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• v.33 no.2
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• pp.158-163
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• 2009

In this study, we synthesized a series of dendritic polystyrene-b-linear poly (t-butyl acrylate) copolymers with well-defined molecular architectures. The hydroxyl group located at the focal point of the second generation dendron bearing polystyrene ($M_n$ = 1000 g/mol) peripheries was converted into amine group via the following stepwise reactions: 1) tosylatoin, 2) azidation, and 3) reduction. On the other hand, the linear poly (t-butyl acrylate)s were prepared by an atom transfer radical polymerization (ATRP) of t-butyl acrylate where benzyl 2-bromopropanoate and Cu(I)Br/PMDETA were used as initiator and catalyst, respectively. To convert the end group of prepared poly (t-butyl acrylate) s into carboxylic acid, a debenzylation was performed using Pd/C catalyst under $H_2$ atmosphere. In the final step, dendritic-linear block copolymers were obtained through a simple amide coupling reaction mediated by 4-(dimethylamino) pyridine(DMAP) and N,N'-diisopropylcarbodiimide(DIPC). The resulting diblock copolymers were shown to have well-defined molecular weights and narrow molecular weight distributions as supported by $^1H$-NMR spectroscopy and gel permeation chromatography(GPC).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.2
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• pp.1-16
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• 2022

The location of the bus stop on urban roads should be installed at a point where it is convenient for users and the impact of bus stops on the traffic flow is minimized. However, the location of the bus stops is determined indiscriminately due to the lack of related research. Therefore, this study developed a traffic accident prediction model and calculated the proper separation distance for the bus stops through an optimization technique. The result of the study indicates that the bus stop can be installed in the form of a mid-block approximately 87 to 166 m away from the intersection in the road section. This result is valid if the number of main road lanes in the road section is 2 to 4 with a level of traffic from 1,000 to 3,000 v/h. In the section with 5 to 6 lanes, it is desirable to install a bus stop close to the intersection by about 42 to 97 m.