• Microbiology and Biotechnology Letters
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• v.30 no.3
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• pp.206-209
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• 2002

For the expression of CGTase gene(cgtS) kom Bacillus stearothemophilus NO2 in Saccharomyces cerevisiae, cgtS gene was subcloned into the Eschepichia coll-yeast shuttle vector, pVT103-U. The constructed plasmid, pVT-CGTS was introduced to 5. cemi-siae 2805 cell, and then the cgtS gene under the control of adhl promoter was successfully expressed in the yeast transformant and 87% of the total activity was detected into the fermentation medium. Therefore, the signal peptide of B. stearothemephilus NO2 CeTase showed high secretion efficiency in 5. cerevisiae. Optimal conditions of the recombinant yeast cell f3r expression of CGTase was achieved, when 5. cerevisiae 2805/pv7-CGTS was cultivated on YP medium at 2% dextrose, pH 5.5,$30^{\circ}C$ and the expression level of CGTase was 0.624units/mL for 48 h culture.

• The Journal of Advanced Prosthodontics
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• v.7 no.5
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• pp.358-367
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• 2015

PURPOSE. The aim of this study was to evaluate the biaxial flexural strength (BFS) of one zirconia-based ceramic used with various veneering ceramics. MATERIALS AND METHODS. Zirconia core material (Katana) and five veneering ceramics (Cerabien ZR; CZR, Lava Ceram; LV, Cercon Ceram Kiss; CC, IPS e.max Ceram; EM and VITA VM9; VT) were selected. Using the powder/liquid layering technique, bilayered disk specimens (diameter: 12.50 mm, thickness: 1.50 mm) were prepared to follow ISO standard 6872:2008 into five groups according to veneering ceramics as follows; Katana zirconia veneering with CZR (K/CZR), Katana zirconia veneering with LV (K/LV), Katana zirconia veneering with CC (K/CC), Katana zirconia veneering with EM (K/EM) and Katana zirconia veneering with VT (K/VT). After 20,000 thermocycling, load tests were conducted using a universal testing machine (Instron). The BFS were calculated and analyzed with one-way ANOVA and Tukey HSD (${\alpha}$=0.05). The Weibull analysis was performed for reliability of strength. The mode of fracture and fractured surface were observed by SEM. RESULTS. It showed that K/CC had significantly the highest BFS, followed by K/LV. BFS of K/CZR, K/EM and K/VT were not significantly different from each other, but were significantly lower than the other two groups. Weibull distribution reported the same trend of reliability as the BFS results. CONCLUSION. From the result of this study, the BFS of the bilayered zirconia/veneer composite did not only depend on the Young's modulus value of the materials. Further studies regarding interfacial strength and sintering factors are necessary to achieve the optimal strength.

• Korean Journal of Veterinary Research
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• v.41 no.2
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• pp.189-195
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• 2001

Single base substitution and deletion mutation have been introducted into the verotoxin 2 (VT2)A subunit gene from O157:H7 isolates to reduce cytotoxicity of VT2 and the cytotoxicity between wild type toxin and mutant toxoid were compared. A M13-derived recombinant plasmid pEP19RF containing a 940bp EcoRI-PstI fragment of VT2A gene was constructed for oligonucleotide-directed mutagenesis. The duoble mutant pDOEX was constructed by point and deletion mutation of two different highly conserved regions of VT2A encoding active site cleft of enzymatic domain. The key residue, Glu 167(GAA) and the pentamer(WGRIS) consisting of the enzymatic domain were replaced by ASP(GAC) and completely deleted in nucleotide sequence analysis of mutant, respectively. In the comparision of vero cell cytotoxicity between wide type toxin and toxoid from mutant, the wild type toxin expressed cytotoxicity in dilution of $10^{-6}$, but the toxid from mutant did not show cytotoxicity to vero cells.

• Microbiology and Biotechnology Letters
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• v.33 no.4
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• pp.267-273
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• 2005

To develop effective and powerful probiotic, Saccharomyces cerevisiae strains producing cellulolytic enzymes were genetically brooded. For the production of exoglucanase, the plasmid pVT-TExo (8.8 kb) was constructed, in which Thermomonosporafusca exoglucanase gene (E3) was under the control of ADHl promoter, and introduced into S. cerevisiae SEY2102. When the transformant, S. cerevisiae SEY2102/pVT-TExo, was cultivated on YPD medium, the total expression level of avicelase reached about 190 unit/l. The secretion efficiency and plasmid stability were about $50\%\;and\;91\%$, respectively. Recombination exoglucanase enzyme bound to avicel better than Clostridium endoglucanase (CelA) and Trichoderma endoglucanase (C4) enzymes. The mixing ratio of E3 and CelA displaying the best synergistic hydrolysis for avicel was observed at 4:1. The mixture of endoglucanase (CelA) and exoglucanase (E3) resulted in 3.2-fold increase of avicelase activity and 2.5-fold enhanced production of sugar production from avicel, compared to the single enzyme treatment.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.269-272
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• 2016

IALA에서 추진하는 e-Navigation 실현전략은 국제적으로 빠른 속도로 진행되고 있다. 국내의 VTS 시스템은 e-Navigation의 진화 상황에서 기술적 국산화 개발과 진화를 동시에 수행 해야 하는 것이다. 이는 국산화 연구개발 이후에 과정이 성공과 실패의 중요한 전환점이 될 것이다. 즉, 국내의 VTS는 사전에 개발되어야 하고, 해외의 e-Navigation으로 진화되는 구조와 매칭 될 수 있도록 추가연구와 상용화가 동시에 고려되어야 한다. e-Navigation의 전체 MSP(Maritime Service Portfolio) 서비스를 효율적으로 제공하기 위하여, VTS 시스템의 역할이 매우 중요하고 해당 VTS 시스템의 진화 없이는 e-Navigation 서비스 또한 불완전하게 진행될 수밖에 없다. 따라서 본 논문에서는 국산화에 따른 상용화와 연구개발간 개념적 문제점을 이해하고, 해외 시스템과 경쟁되는 상용화 시스템을 개발하고 e-Navigation으로 진화하기 위하여, 연구개발 고도화 및 상용화를 통하여 품질을 제고하는 방안을 고려하고자 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.117-119
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• 2011

e-navigation은 2006년부터 국제해사기구(IMO, International Maritime Organization), 국제항로표지기구(IALA, International Association of Lighthouse Authorities), 국제수로기구(IHO, International Hydrographic Organization) 등의 국제기구를 주축으로 한국, 일본, 영국, 노르웨이 및 독일 등 해운선진국에서 활발하게 개발되고 있다. IMO에서는 2012년까지 e-navigation 전략이행 계획 개발을 완료할 예정이며, 이후에는 전략이행 계획에 따라 e-navigation은 이행될 예정이다. 본 연구에서는 e-navigation개발에 대한 국제동향을 파악하고, 그 개발 내용을 분석하였으며, 육상측 e-navigation시스템으로써 중추적 역할을 하게 될 VTS의 발전 전망에 대하여 연구하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.5
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• pp.440-451
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• 2013

Recently, researches of technology and standardization for maritime safety are proceeding internationally. In particular, some technologies and strategies for e-Navigation have been developed and the necessity of development of next generation VTS (Vessel Traffic Service) has been raised in Korea. In order to construct user oriented VTS system for domestic environment, VTS operators are asked for their requirements related to developing VTS and the opinions should be reflected in the VTS. So in this paper, we collect the requirements from fifteen VTS centers in the country and we also analyze them. Furthermore, we propose an ASM (Application Specific Messages) service, which was not supported by current VTS, and we verify the proposed ASM through AIS (Automatic Identification System) system and simulation terminal for maritime safety.

• Korean Journal of Veterinary Service
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• v.21 no.2
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• pp.149-156
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• 1998

The present study was carried out to investigate the biochemical characteristics, antibiotic susceptibility and toxin(ST, LT, VT1.2 type) production test of 60 Escherichia coli isolated from diseased domestic animals in southern area of Kyungbuk province from April to December 1997. 1. The biochemical and cultural reaction were consistent with the classification criteria of Edwards and Ewing. 2. In antibiotic susceptibility test, 60 E coli showed highly susceptible to CL(96.7%), XNL(86.7%), AN(81.7%), SXT(61.7%), Lin(55%), GM(53.3%), KM(41.7%), N(41.7%), ENR(40%), AM(40%), CF(30%), 5(13.3%) and Te(11.7%), in order. 3. Sixty E coli isolates were multiful resistant to seven or more antibiotics incombination. 4. Three strains for 60 E coli were detected heat-labile enterotoxin(LT) and that's titers were 2, 8 and 16, respectively.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.773-778
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• 2006

The objective of this study was to evaluate three verocytotoxin-producing Escherichia coli (VTEC) detection kits to detect the presence of VT genes: Doupath Verocytotoxin (GLISA) developed by MERCK, ProsPect Shiga Toxin E. coil (STEC) Microplate Assay (ELISA) developed by Remel, and a polymerase chain reaction method. Our laboratory verified artificially inoculated samples. All three methods could detect very low numbers of VTEC, but VT-PCR had the best sensitivity for VTEC detection. From April through September 2005, 257 ground-beefs from supermakets and traditional markets were examined for the presence of VTEC by polymerase chain reaction immediately after purchase and total viable counts (TVC) were determined. VTEC was isolated from 30 of 257 ground-beefs. A variety of serogroups was found, including 10 stains belonging to the virulence type EHEC, but major serogroups such as O157, O26 and O111 were nor found.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.3
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• pp.423-427
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• 2004

Seventy-six animals including cattle, sheep, horses, 6 species of zoo animals were employed for collection of fresh feces in order to detect verotoxigenic Esherichia coli (VTEC) by safe, quick and sensitive PCR-based molecular methods. Bacterial cell disruption with bead-beating followed by bacterial DNA purification with hydroxyapatide chromatography and gel filtration allowed DNA preparation from animal feces with high recovery and purity. A mountain goat was firstly shown by PCR and sequencing to shed verotoxin 2 gene (vt2) that was used to generate vt2 probe and second primer set for nested PCR to attempt more sensitive detection. Most sensitive nested PCR revealed that 45% of tested cattle and 47% of tested zoo animals were VTEC-positive, while least sensitive normal PCR detected VTEC from none of these animals except a mountain goat. Moderately sensitive detection by PCR in combination with hybridization suggested that the VTEC density varied between the VTEC-positive cattle.