• Journal of Microbiology and Biotechnology
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• v.18 no.1
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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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• v.7 no.3
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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.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.6
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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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• v.22 no.9
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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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• 2003.10a
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• pp.341-345
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• 2003

Effect of immobilization on the production of human granulocyte-macrophage colony-stimulating factor (hGM-CSF) by Nicotiana tabacum cells was investigated using polyurethane foam as immobilization matrices. The cell activity and the hGM-CSF production were maintained for 16 days in spite of 3 times of media exchange. Under the same conditions of temperature and agitation rate, maximum concentrations of hGM-CSF in a 500-mL spinner flask and 100-mL Erleuneyer flasks were 17.3 ${\mu}g/L$ and 9.8 ${\mu}g/L$, respectively. Consequently high hGM-CSF production could be possible in spinner flask when the rate and amount of media exchange were optimized.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.289-292
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• 2003

Effects of immobilization on the production of human granulocyte-macrophage colony-stimulating factor (hGM-CSF) by Nicotiana tabacum cells were investigated using alginate and polyurethane foam as immobilization matrices. Encapsulation of the cells in alginate decreased protein production by 50% compared with that of suspension culture. Maximum hGM-CSF concentration was obtained by the cells immobilizaed in polyurethane foam. High hGM-CSF production could be possible when polyurethane foam was used because of high specific production and easy immobilization for cell recycling process with high cell density.

• KSBB Journal
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• v.8 no.4
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• pp.351-357
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• 1993

Three immobilization techniques and free cell system were tested to determine the most effective technique for the treatment of pulp waste effluent. The tests were conducted using Phanerochaete chrysosporium as a biocatalyst in a process designed to treat pulp waste effluent. The results show that Ca-alginate gel was the best immobilization material. The chosen material improved the stability and increased the removal efficiency of the system. The experiment using the chosen material was mom- bored for 400 hours with no significant changes in the state of the fungus. Common problems with other immobilization materials and free cell system were oxygen transfer resistance caused by air channelling and clogging in the bioreactor.

• Journal of Microbiology and Biotechnology
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• v.22 no.10
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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%.

• Korean Journal of Pharmacognosy
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• v.26 no.3
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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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• 2005.10a
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• pp.741-741
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• 2005