• 대한토목학회논문집
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• 제3권3호
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• pp.95-106
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• 1983

사면(斜面)의 3차원(次元) 파괴(破壞)의 신뢰성(信賴性) 해석(解析)에 안전율(安全率)대신 파괴확률(破壞確率)이 사용(使用)되었다. 강도정수(强度定數)는 정규분포(正規分布)와 베타분포(分布)(beta distribution)로 가정하였고 특별(特別)한 신뢰도(信賴度)와 최우추정법(最尤推定法)에 의하여 구간추정(區間推定)을 하였다. 정규분포(正規分布)와 베타분포(分布)의 의사무작위변수(擬似無作爲變數)는 중심극한정리(中心極限定理)와 Rejection방법(方法)에 따라 일양분포변환방법(一樣分布變換方法)을 사용(使用)하여 발생(發生)시켰고 몬테칼로방법 (Monte-Carlo Method)에 의한 파괴확률(破壞確率)은 다음과 같이 정의(定義)된다. $$P_f$$=M/N M: 파괴회수(破壞回數) N: 시행회수(施行回數) 본(本) 연구(硏究)의 결론(結論)은 강도정수(强度定數)를 정규분포(正規分布)로 가정한 경우에는 주어진 파괴표면(破壞表面)에 대하여 어떤 해석방법(解析方法)과 차원(次元)에 대해서도 안전율(安全率)과 파괴확률(破壞確率)과의 관계는 일정(一定)하였으나 베타분포(分布)로 가정 한 경우에는 일정(一定)한 관계가 나타나지 않았다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권1호
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• pp.43-51
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• 2002

The cloning and expression of $\beta-glucosidase$ II, encoded by the gene ${\beta}glu2$, from thermotolerant yeast Pichia etchellsii into Escherichia coli is described. Cloning of the 7.3 kb BamHI/SalI yeast insert containing ${\beta}glu2$ in pUC18, which allowed for reverse orientation of the insert, resulted in better enzyme expression. Transformation of this plasmid into E. coli JM109 resulted in accumulation of the enzyme in periplasmic space. At $50^{\circ}C$, the highest hydrolytic activity of 1686 IU/g protein was obtained on sophorose. Batch and fed-batch techniques were employed for enzyme production in a 14 L bioreactor. Exponential feeding rates were determined from mass balance equations and these were employed to control specific growth rate and in turn maximize cell growth and enzyme production. Media optimization coupled with this strategy resulted in increased enzyme units of 1.2 kU/L at a stabilized growth rate of $0.14\;h^{-l}$. Increased enzyme production in bioreactor was accompanied by formation of inclusion bodies.

• 미생물학회지
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• 제31권1호
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• pp.93-98
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• 1993

수계생태계에서 유기물질의 순환을 이해하기 위하여 팔당호에서 종속영양 활성도와 세균세포의 효소활성의 계절절 변화를 연구하였다. 팔당호 I 의 glucose 전환시간은 수층, 퇴적토에서 2-1,300 시간, 17-170 시간, protein hydrolysate 는 5-900 시간, 15-240 시간, acetic acid 는 4-350 시간, 15-230 시간으로 계절적인 변화를 나타냈다. Glucose, protein hydrolysate, acetate 각각의 호흡율은 수층에서 23-32%, 38-41%, 22-28%로 나타났고 퇴적토에서는 34%, 61% and 41% 로 나타났다. 이 결과로 3가지 유기물질 종류 모두가 수층보다 퇴적토에서는 높은 율로 호흡됨을 알 수 있었다. 한편 세균의 $\alpha$-glucosidase, $\beta$-glucosidase, N-acetyl-$\beta$-D-glucosaminidase, aminopeptidase 활성력을 살펴본 결과 수층에서는 효소 각각에 대해 32-44%, 31-32%, 18-34% 61-67% 의 범위를 나타내었고 퇴적토에서는 34%, 40%, 23% 65%로 나타났다.

• 생명과학회지
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• 제19권12호
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• pp.1718-1723
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• 2009

Chromosomal 인 SHV-11 $\beta$-lactamase가 plasmid를 매개로 다른 균주로 전달 되는 현상은 흔하지 않다. 본 연구에서는 플라스미드성 SHV-11 $\beta$-lactamase를 동시에 가지고 있는 ESBL생성 두 균주를 검출하였다. 따라서 이들 균주에 대한 유전적 특성과 임상적 의의에 대해 알아보고자 하였다. Vitek system과 이중디스크확산법을 이용하여 ESBL생성균주를 검출하였고, PCR과 DNA 염기서열분석을 이용하여 SHV-11 $\beta$-lactamase를 가지고 있는 ESBL생성균주를 확인 하였다. 이들 균주를 교차접합실험과 형질전환실험을 이용하여 유전자전이를 확인하고 액체배지 희석법으로 3세대 cephalosphorin 항생제에 대한 최소억제농도를 측정하였다. 이들 균주의 유전형 분석결과는 SHV-11 $\beta$-lactamase 유전자와 CTX-M-15 ESBL 유전자를 동시에 가지고 있었다. 3세대 cephalosphorin 항생제에 대한 최소억제농도는 SHV-11 $\beta$-lactamase와 CTX-M-15 ESBL 유전자를 동시에 가지고 있는 균주에서 $64{\mu}g/ml$ 이상이었고, SHV-11 $\beta$-lactamase 만을 가지고 재조합 한 균주에서 $0.5{\mu}g/ml$ 이하로 나타났다.

• 원예과학기술지
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• 제29권3호
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• pp.267-272
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• 2011

${\beta}$-carotene hydroxylase는 carotenoids의 생합성 경로에서 astaxanthin 및 zeaxanthin 합성에 관여하는 주요 효소이다. Astaxanthin과 zeaxanthin은 비타민 A 전구체보다 항암효과가 더 높다고 보고되고 있다. 따라서 ${\beta}$-carotene hydroxylase 유전자(ChyB)를 토마토 잎에서 분리하고 binary 벡터에 클로닝 한 후 pIG121-ChyB-tom으로 명명하였다. 토마토 ChyB 유전자를 Agrobacterium-mediated infiltration 방법을 이용하여 생육 8주 된 담배 잎에 일시적 형질전환을 하였다. 감염 0, 1, 2, 3일 후 RT-PCR 한 결과 담배에서는 거의 발현되지 않았던 ${\beta}$-carotene hydroxylase 전사체가 감염 1일 후부터 증가하여 2일 후 최대 전사량을 보이고 3일 후부터 감소하는 경향을 나타내었다. 이 결과를 바탕으로 감염 후 0, 2, 3일째 담배 잎을 채취하여 항산화 효능을 측정한 결과, 감염 2일 후 1,1-diphenyl-pricryl hydrazyl(DPPH) radical 소거 활성이 대조구에 비해 약 30% 증가하는 것을 확인하였다. 이 연구결과를 통해 외래 유용 유전자를 원예작물에 형질전환하여 항산화 및 항암효과가 우수한 zeaxanthin 및 astaxanthin 등 oxy-carotenoids의 함유량을 증진시킨 새로운 기능성 토마토 및 다양한 원예작물의 신품종 개발에 이용될 수 있을 것으로 기대된다.

• BMB Reports
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• 제44권8호
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• pp.512-516
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• 2011

Establishment of immortalized human dermal papilla cells (DPCs) retaining the characteristics of DPCs would be a great help for hair researchers. We recently established a simian virus 40T (SV40T)-transformed human DP cell line (SV40TDPC). However, the cell line senesced around passage 25 and ceased proliferation. In this study, we introduced the human telomerase reverse transcriptase (hTERT) gene into SV40T-DPC and established an immortalized human DP cell line. The cell line, SV40T-hTERT-DPC, did not induce tumors when inoculated into nude mice. SV40T-hTERT-DPC maintained morphology of early passage DPCs, expressed markers of DPCs, and retained responses to Wnt/${\beta}$-catenin and bone morphogenic protein (BMP) signaling pathways known to be required for hair-inducing activity of DPCs. The data strongly suggest that SV40T-hTERT-DPC retains many characteristics of human DPCs in vivo without malignant transformation.

• Plant Biotechnology Reports
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• 제2권3호
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• pp.219-226
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• 2008

Transgenic plants with the herbicide-resistance gene (bar gene) were obtained via organogenesis from isolated mesophyll protoplasts of Nierembergia repens after applying electroporation. Transient ${\beta}-glucuronidase$ (GUS) activity of electroporated protoplasts assayed 2 days after applying an electric pulse showed that optimum condition (transient GUS activity 319 pmol 4 MU/mg per min and plating efficiency 2.43%) for electroporation was 0.5 kV/cm in field strength and $100{\mu}F$ in capacitance. The protoplasts electroporated with the bar gene at this condition initiated formation of microcolonies on medium after 2 weeks. After 4 weeks of culture, equal volume of fresh 1/2-strength Murashige and Skoog (MS) medium containing 0.2 mg/l bialaphos was added for selection of transformed colonies. After 6 weeks of culture, growing colonies were transferred onto regeneration medium containing 1.0 mg/l bialaphos, on which they formed adventitious shoots 1-2 months after electroporation. The adventitious shoots rooted easily after transfer onto MS medium with bialaphos lacking plant-growth regulators. Transformation of these regenerants with the bar gene was confirmed by Southern analysis. Some of the transformants showed strong resistance to the application of bialaphos solution at 10.0 mg/l.

• ALGAE
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• 제26권1호
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• pp.3-20
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• 2011

The physiology of the unicellular green alga Dunaliella salina in response to abiotic stress has been studied for several decades. Early D. salina research focused on its remarkable salinity tolerance and ability, upon exposure to various abiotic stresses, to accumulate high concentrations of $\beta$-carotene and other carotenoid pigments valued highly as nutraceuticals. The simple life cycle and growth requirements of D. salina make this organism one of the large-scale commercially exploited microalgae for natural carotenoids. Recent advances in genomics and proteomics now allow investigation of abiotic stress responses at the molecular level. Detailed knowledge of isoprenoid biosynthesis mechanisms and the development of molecular tools and techniques for D. salina will allow the improvement of physiological characteristics of algal strains and the use of transgenic algae in bioreactors. Here we review D. salina isoprenoid and carotenoid biosynthesis regulation, and also the biotechnological and genetic transformation procedures developed for this alga that set the stage for its future use as a production system.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2002년도 춘계 학술대회지
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• pp.48-50
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• 2002

A strategy for development of a functional rice in proved with human lactoferrin and enhancement of nutrient compounds was planned. For the purposes we have cloned and characterized a human lactoferrin cDNA from human mammary gland cDNA library A endosperm storage vacuole targeting sequence and the cDNA fragment was linked to endosperm specific glutelin promoter. The fusion gene fragment was inserted into a binary vector containing MAR gene. In addition a new ${\beta}$-galactosidase gene from Bifidobacterium of human was used as a reporter gene in the vector system, Rice plants showing a high concentration of amino acids in the endosperm cells were developed by using a biochemical mutation and bred for the transformation with the binary vector system Finally we have established a transformation method for the rice endosperm cells.

• Journal of Pharmaceutical Investigation
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• 제41권6호
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• pp.371-376
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• 2011

The objective of this work was to investigate the existence of new crystal forms of tulobuterol which is used to prevent morning asthma attacks by ${\beta}_2$ agonist and the transformation of crystal forms. Three crystal forms of tulobuterol have been isolated by recrystallization and Form 2 was transformed to Form 4 at 52% RH and 95% RH and these four crystal forms are characterized by differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD) and thermogravimetric analysis (TG). The DSC and PXRD patterns of four crystal forms of tulobuterol were different respectively. The dissolution patterns of these three crystal forms of tulobuterol were studied and they showed significant differences in the dissolution rate. After storage of 2 months at 0% RH (silica gel, $20^{\circ}C$), 52% RH (saturated solution of $Na_2Cr_2O_7{\cdot}2H_2O/20^{\circ}C$) and 95% RH (saturated solution of $Na_2HPO_4/20^{\circ}C$), Form 1 and Form 3 were not transformed. But Form 2 was transformed to Form 4 at 52% RH and 95% RH.