• Journal of Microbiology and Biotechnology
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• 제18권1호
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• pp.145-152
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• 2008

A cell-based in vitro exposure system was developed to determine whether oxidative stress plays a role in the cytotoxic effects of volatile organic compounds (VOCs) such as benzene, toluene, xylene, and chlorobenzene, using human epithelial HeLa cells. Thin films based on cysteine-terminated synthetic oligopeptides were fabricated for immobilization of the HeLa cells on a gold (Au) substrate. In addition, an immobilized cell-based sensor was applied to the electrochemical detection of the VOCs. Layer formation and immobilization of the cells were investigated with surface plasmon resonance (SPR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The adhered living cells were exposed to VOCs; this caused a change in the SPR angle and the VOC-specific electrochemical signal. In addition, VOC toxicity was found to correlate with the degree of nitric oxide (NO) generation and EIS. The primary reason for the marked increase in impedance was the change of aqueous electrolyte composition as a result of cell responses. The p53 and NF-${\kappa}B $ downregulation were closely related to the magnitude of growth inhibition associated with increasing concentrations of each VOC. Therefore, the proposed cell immobilization method, using a self-assembly technique and VOC-specific electrochemical signals, can be applied to construct a cell microarray for onsite VOC monitoring.

• Asian-Australasian Journal of Animal Sciences
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• 제7권3호
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• pp.397-400
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• 1994

The effect of xylazine administration on plasma cortisol, prolactin, glucose and packed cell volume (PCV) responses to immobilization and heat stress was investigated. Immobilization of rats for 2 hours by ligation of the fore and hind legs strongly caused approximately two-fold increase in plasma cortisol and prolactin levels. Plasma glucose and PCV were not significantly changed. Pretreatment of immobilized rats with xylazine (20 mg/kg body weight i.m.) resulted in approximately 20% reduction in both plasma cortisol and prolactin concentrations. A marked hyperglycemia and increase in the PCV value was observed. On the other hand, rats exposed to acute heat stress ($40^{\circ}C$, and 60% relative humidity) for 2 hours, also developed two fold increase in both plasma cortisol and prolactin concentrations and the pretreatment with xylazine caused a 20% reduction in the levels of both hormones. Plasma glucose level was not significantly changed in heat stressed rats but it was markedly increased after pretreatment with xylazine. PCV was significantly incrcased under heat stress and pretreatment with xylazine induced a pronounced elevation in this value. It was suggested that stimulation of cortisol and prolactin secretion in response to immobilization or heat stress can be partially reduced by an alpha 2-adrenergic agonist.

• 동의생리병리학회지
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• 제17권6호
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• pp.1393-1403
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• 2003

The genetic effects of restraint stress challenge on HPA axis and the therapeutic effect of Boshimgeonbi-Tang on the stress were studied with cDNA microarray analyses on hypothalamus using an immobilization-stress mouse as stress model. Male CD-1 mice were restrained in a tightly fitted and ventilated vinyl holder for 2hours once a day, and this challenge was repeated for seven consecutive days. The body weights of the immobilization-stress mice were diminished about 25 percent degree as compared to normal ones. Seven days later, total RNA was extracted from the organs of the mouse, body-labeled with CyDye/sup TM/ fluorescence dyes (Amersham Bioscience Co., NJ), and then hybridized to cDNA microarray chip. Scanning and analyzing the array slides were carried out using GenePix 4000 series scanner and GenePix Pro/sup TM/ analyzing program, respectively. The expression profiles of 109 genes out of 6000 genes on the chip were significantly modulated in hypothalamus by the immobilization stress. Energy metabolism-, lipid metabolism-, apoptosis- and signal transduction-related genes were transcriptionally activated whereas DNA repair-, protein biosynthesis-, and structure integrity-related genes were down-regulated in hypothalamus. The 58 genes were up-regulated by the mRNA expression folds of 1.5 to 7.9. and the 51 genes were down-regulated by 1.5 - 3.5 fold. The 20 genes among them were selected to confirm the expression profiles by RT-PCR. The mRNA expression levels of Tnfrsf1a (apoptosis), Calm2 (cell cycle), Bag3 (apoptosis), Hspe1 (protein folding), Aatk (apoptosis), Dffa (apoptosis), Itgb1 (cell adhesion), Vcam1 (cell adhesion), Fkbp5 (protein folding), BDNF (neuron survival) were restored to the normal one by the treatment of Boshimgeonbi-Tang.

• Journal of Microbiology and Biotechnology
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• 제22권9호
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• pp.1218-1223
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• 2012

${\varepsilon}$-Poly-$_L$-lysine (${\varepsilon}$-PL), produced by Streptomyces or Kitasatospora strains, is a homo-poly-amino acid of $_L$-lysine, which is used as a safe food preservative. The present study investigates the combined use of cell immobilization and in situ adsorption (ISA) to produce ${\varepsilon}$-PL in shaken flasks. Loofah sponge-immobilized Streptomyces ahygroscopicus GIM8 produced slightly more ${\varepsilon}$-PL than those immobilized on synthetic sponge, and sugarcane bagasse. Moreover, loofah sponge supported the maximum biomass. Hence, loofah sponge was chosen for cell immobilization. Meanwhile, the ion-exchange resin D152 was employed for ISA. The loofah sponge-immobilized cells produced $0.54{\pm}0.1g/l$ ${\varepsilon}$-PL, which significantly increased to $3.64{\pm}0.32g/l$ after combining with ISA through the addition of resin bags. The free cells with ISA using the dispersed resin yielded $2.73{\pm}0.26g/l$ of ${\varepsilon}$-PL, an increase from $0.82{\pm}0.08g/l$. These data illustrate that the proposed combination method improved production most significantly compared with either immobilization or ISA only. Moreover, the immobilized cells could be repeatedly used and an ${\varepsilon}$-PL total amount of $8.05{\pm}0.84g/l$ was obtained. The proposed combination method offers promising perspectives for ${\varepsilon}$-PL production.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.341-345
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• 2003

형질전환된 담배세포 배양을 이용한 hGM-CSF 생산에 있어 polyurethane foam 내 고정화법을 이용하여 연속배양의 가능성을 확인하였고 spinner flask에서의 배양에 따른 영향을 알아보았다. 16일 동안 3번의 배지교환에도 세포의 활성이 유지되어 hGM-CSF 생산량은 계속적으로 증가하였다. 온도와 교반속도를 동일하게 하였을 때 spinner flask에서의 hGM-CSF 생산량은 17.3 ${\mu}g/L$으로 100-mL flask의 9.8 ${\mu}g/L$보다 증가하였다. 따라서 최적의 배지교환 속도와 양을 결정하여 spinner flask에서 연속배양을 실시할 경우 세포 재사용이라는 경쟁력과 함께 높은 hGM-CSF 생산량이 얻어질 것으로 예상된다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.289-292
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• 2003

형질전환된 담배세포배양을 이용한 hGM-CSF 생산에 있어 고정화가 미치는 영향을 연구하였다. Alginate bead를 이용한 고정화 세포의 경우 hGM-CSF 생산이 6일째 $3.35\;{\mu}g/L$로써 현탁세포 $6.01\;{\mu}g/L$의 약 50%에 미쳤고 polyurethane foam 내 고정화 한 경우는 세포 생장은 낮았으나 hGM-CSF 생산량은 6일째 $6.67\;{\mu}g/L$로 가장 높았다. 높은 비 생산량을 보이는 polyurethane foam내 고농도로 세포를 포집시킨 후 세포 재사용이 용이한 장점을 이용하여 연속공정에 적용할 경우 더 높은 hGM-CSF의 생산이 기대된다.

• KSBB Journal
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• 제8권4호
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• pp.351-357
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• 1993

펄프 폐수처리를 위한 효과적인 생물학적 처리법 으로서 세 가지 고정화 방법과 자유균체를 이용한 방법을 사용하여 실험하였다. 균체로서는 Phaηe­r rochaete chrysosporium을 이용하였다. 고정화방법 중 Ca-alginate gel을 담체로 샤용한 방법이 가장 우수하였다. 이 방법은 안정성과 처리 효율변에서 좋은 결과를 보였으며, 약 400시간 동안 균체의 커다란 상태변화없이 반응시킬 수 있었다. 다른 고정화 방법들과 자유균체를 이용한 방법들 의 가장 큰 문제점은 생물 반응기 안에서의 공기 c channelling 현상에 의한 산소전달 저항과 균체끼리 의 clogging으로 인한 반응기 내부의 제어가 힘들게 된 것이었다.

• Journal of Microbiology and Biotechnology
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• 제22권10호
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• pp.1395-1400
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• 2012

In this study, we investigated various cultural and operational factors to enhance electricity generation in a microbial fuel cell (MFC) using Geobacter sulfurreducens. The pure culture of G. sulfurreducens was cultivated using various substrates including acetate, malate, succinate, and butyrate, with fumarate as an electron acceptor. Cell growth was observed only in acetate-fed medium, when the cell concentrations increased 4-fold for 3 days. A high acetate concentration suppressed electricity generation. As the acetate concentration was increased from 5 to 20 mM, the power density dropped from 16 to $13mW/m^2$, whereas the coulombic efficiency (CE) declined by about half. The immobilization of G. sulfurreducens on the anode considerably reduced the enrichment period from 15 to 7 days. Using argon gas to create an anaerobic condition in the anode chamber led to increased pH, and electricity generation subsequently dropped. When the plain carbon paper cathode was replaced by Pt-coated carbon paper (0.5 mg $Pt/cm^2$), the CE increased greatly from 39% to 83%.

• 생약학회지
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• 제26권3호
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• pp.227-238
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• 1995

Recent reports on biotransformation of monoterpene alchols, aldehydes, acetates and epoxides are summerized. The studies have focused on stereospecific reaction of the functional groups of exogenous foreign substrates by foreign plant cells and micro-organisms. An another important aspect of research is the development of the immobilization technique for cells or related enzymes.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.741-741
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• 2005