• 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.

• Journal of Acupuncture Research
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• 제35권4호
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• pp.207-213
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• 2018

Background: The purpose of this study was to examine the effect of Dokhwalgisaeng-tang on immobilization-induced muscle atrophy. Methods: Twenty young male Sprague-Dawley rats were divided into 2 groups. The rats in Dokhwalgisaeng-tang group were orally administered Dokhwalgisaeng-tang water extract, and the rats in the control group were given saline only. Hind limb immobilization was performed with casting tape to keep the left ankle joint in a fully extended position. No intervention was performed on the right leg which was used as an intact region. After 2 weeks of immobilization, all animals were sacrificed, and the gastrocnemius muscle was dissected from both legs and weighed. The morphology of the right and the left gastrocnemius muscle in both the Dokhwalgisaeng-tang and the control group was assessed by hematoxylin and eosin staining. The muscle cross sectional area was examined by image analysis (Axiovision LE software). In addition, immunohistochemical staining was carried out using the free-floating method, and the number of apoptotic related proteins were counted (anti-BAX, anti-Bcl-2). Results: Dokhwalgisaeng-tang showed a significant protective effect against the reduction of the left gastrocnemius muscle (weight and muscle cross sectional area) compared with the control group. Moreover, the treatment with Dokhwalgisaeng-tang significantly reduced protein expression of BAX and increased protein expression of Bcl-2 in the gastrocnemius muscle compared with the control group. Conclusion: Dokhwalgisaeng-tang showed protective effects against disuse muscle atrophy, potentially through altered BAX and Bcl-2 protein expression in the gastrocnemius muscle.

• Food Science and Biotechnology
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• 제14권3호
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• pp.317-322
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• 2005

A simple and convenient method of immobilizing dextransucrase via an affinity interaction is described, along with the use of this system to synthesize leucrose. Dextransucrase was produced in sucrose-free medium by fermenting a constitutive mutant of Leuconostoc mesenteroides NRRL B-512F and was separated using an ultrafiltration membrane. The purified enzyme was free of dextran polymer, which previously was always found with the sucrose-induced enzyme. Therefore, it was possible to immobilize the enzyme on dextran-based resins using an affinity interaction. Sephadex G-200 was the best resin for immobilizing the dextransucrase and gave a fast flow rate through the packed column. The immobilized dextransucrase retained more than 80% of its specific activity after immobilization ($K_m\;=\;18.1\;mM$ and $k_{cat}\;=\;450\;sec^{-1}$ vs. 13.1 mM and $640\;sec^{-1}$, respectively, for the free enzyme). The immobilized dextransucrase showed improved stability over a pH range of 4.0 to 6.5 and at moderately high temperatures over $40^{\circ}C$. When immobilized dextransucrase was used to synthesize leucrose via the transfer reaction with sucrose and fructose, about 74% of the sucrose was converted into leucrose after one day, and the half-life of the enzyme activity was 15 days. Regeneration of the resin by supplementation with dextransucrase enabled the recovery of the initial activity of the system, but both the reaction and the flow rate were lower, probably owing to the accumulation of dextran inside the resin.

• Applied Biological Chemistry
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• 제26권4호
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• pp.222-230
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• 1983

본 연구에서는 저자등이 분리한 바 있는 Streptomyces griseolus가 분비한 xylose 이성화 효소(D-xylose ketol isomerase, EC 5.3.1.5, 포도당 이성화 효소)의 고정화 및 이 고정화 효소에 의한 파일롯트 규모의 이성화당 생산에의 응용을 시도하였다. 세포내 분비된 Xylose 이성화 효소를 함유한 미생물 균체를 호모 게나이저로 $500kg/cm^2$압력하에 파쇄한 결과 원 효소 역가의 98.8%가 얻어졌고, lysozyme으로 분해 했을 때는 54.7%가 얻어졌다. 이 효소의 고정화를 위한 담체로서는 Diaion HP 20, Duolite A-7, Amberlite IRA 93 및 94와 같은 포리스형 수지류가 효과적임이 밝혀졌고, Amberlite IRA 93에 대한 재생 형태는 $BO_4--$가, Diaion HP 20에 대해서는 $HCO_3-$가 효과적이었다. Amberline IRA 93에 대한 고정화 최적 조건은 pH 8.0에 $55^{\circ}C$로서 80.6%의 효소 고저오하 수율을 나타내었으며 효소 활성 반감기는 $65^{\circ}C$에서 24일 이상이었다. Amberlite IRA 93에 효소를 탈착(脫着) 실험한 결과, 담체는 재 사용이 가능 하였으며 2,3,4,5회째의 효소의 재 고정화율은 각각 98.2, 93.3, 90.7 및 87.5%를 나타내었다. 고정화 효소의 최적 반응 온도는 $60{\sim}70^{\circ}C$로 원효소의 경우에 비하여 다소 낮아지면서 폭이 넓어졌으며, 최적 pH는 $8.0{\sim}8.3$으로 알카리 쪽으로 이동하였다. 파일롯트 규모로 본 고정화 효소 충전탑(내경 30cm, 높이 85cm)에 의한 이성화당의 생산을 시도하였던바, 고정화 효소(350 IXIU/ml-R) 1리터가 30일동안에 약 293리터의 이성화당을 생산할 수 있는 것으로 나타났다.

• 생명과학회지
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• 제27권10호
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• pp.1145-1151
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• 2017

세제에 의하여 대장균의 periplasm에서 penicillin G amidase (PGA)를 방출하는 방법을 연구하였다. 결과적으로 세제와 lysozyme의 혼합 작용이 효과적인 것으로 나타났다. 세포 투과성의 최적 조건을 알아보기 위하여 세제의 종류, 농도, pH, 반응 시간, 온도 등의 영향을 살펴보았다. 그리하여 대장균에서 재조합 PGA를 periplasm에서 방출하는 모델을 만들 수 있었고 방출된 PGA를 농축할 수 있었다. 실리카 구슬을 이용한 고정화 시스템으로 PGA 용액을 농축할 수 있었으며, 더 이상의 정제 과정 없이 순수하게 추출 할 수 있었다. 고정화된 PGA는 penicillin G 생성의 원료인 6-APA를 생산하는데 사용할 수 있었다. 이 방법은 대장균으로부터 재조합 단백질을 추출하는 간단한 방법이며 고정화 PGA를 이용하여 ${\beta}-lactam$ 항생물질의 산업적 생산 이용될 수 있을 것으로 사료된다.

• Macromolecular Research
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• 제12권6호
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• pp.586-592
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• 2004

Poly(glycidyl methacrylate)-grafted polyethylene microbeads (POPM) presenting epoxy groups were prepared by radiation-induced graft polymerization of glycidyl methacrylate on the polyethylene microbead. The obtained POPM was characterized by IR spectroscopic, X-ray photoelectrons spectroscopy (XPS), scanning electron microscope (SEM), and thermal analyses. Furthermore, the abundance of epoxy groups on the POPM was determined by titration and elemental analysis after amination. The epoxy group content was calculated to be in the range 0.29-0.34 mmol/g when using the titration method, but in the range 0.53-0.59 mmol./g when using elemental analysis (EA) after amination. The lipase was immobilized to the epoxy groups of the POPM under various experi­mental conditions, including changes to the pH and the epoxy group content. The activity of the lipase-immobilized POPM was in the range from 160 to 500 unit/mg-min. The activity of the lipase-immobilized POPM increased upon increasing the epoxy group content. The lipase-immobilized POPM was characterized additionally by SEM, elec­tron spectroscopy for chemical analysis (ESCA), and EA.

• 대한본초학회지
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• 제22권2호
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• pp.127-135
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• 2007

Objective : Investigation of the anti-stress effects of Sihosogansan Methods : Passive avoidance test(PAT) was performed after applying immobilization stress in water to rats. Also, forced swimming test(FST) was performed to another rats and after FST, the degree of Tyrosine Hydroxylase(TH) expression was measured with immunohistochemical method in the regions of locus coeruleus(LC) and ventral tegmental area (VTA). Results : In the PAT after immobilization stress in water, response latency was significantly increased in the Sihosogansan(400mg/kg) group in comparison with the control group. In the FST, immobility was significantly decreased in the Sihosogansan groups (100mg/kg, 400mg/kg), comparing with the control group. Stress-induced TH increases were suppressed in the Sihosogansan groups (100mg/kg, 400mg/kg) at the LC and the VTA region respectively. Conclusion : Sihosogansan can improve memory ability of rats, reduce behavior of depression in rats, decrease TH-immunoreactive cells at the LC and VTA region in rat, and it may be concluded that Sihosogansan has significant effect in reducing stress.

• 한국미생물·생명공학회지
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• 제21권4호
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• pp.373-380
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• 1993

When the cells of yeast K35 were immobilized in Ca-alginate gel, cell concentration and viability decreased as alginate concentration increased. Considering the results, 2% (w/v) Ca-alginate concentration would be suitable. Among various concentrations of additives and cross-lin-king agent, the addition of 1.67% (w/v) of bentonite together with 0.33% (v/v) of glutaraldehyde (ABG bead) resulted in the highest ethanol production of 1.8%(w/v), using YPD medium containing 2% glucose. ABG bead seemed to be more resistant to phosphate ion than Ca-alginate bead. 0.33%(w/v) of phosphate was a proper concentration for the ethanol production by ABG bead. Scanning electron microscopic observation depicted that the immobilized cells on the bead surface were coated by alginate gel and that the cells in the internal bead were cross-linked with alginate matrix. When repeated-batch culture was performed with ABG bead for 40 days in a packed-bed reactor, ethanol concentration of about 90~110 g/l-gel was maintained. Cell viability was maintained around 70%, and outgrowing cell concentration was below 6.3% of total cell concentration. Consequently, the results showed that ABG head was a potential carrier for continuous production of ethanol compared to conventional Ca-alginate bead.

• 한국미생물·생명공학회지
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• 제28권1호
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• pp.45-51
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• 2000

Photobacterium phosphoreum was used for the study of bioluminescence response to toxic substances including phenol, As2O3, SoO2, and CrO3 in view of developing monitoring system. measurement of inhibition of bioluminescence in P. phosphoreum has been proposed as a sensitive and raped procedure to monitor toxic substances. The concentration of toxic substance causing 50% light reduction(EC50) in bioluminescence intensity was determined with free and immobilized P. phosphoreum, The minimum inhibitory concentrations (MICs) for bioluminescence emission were found to be 400ppm for As2O3, 800ppm for phenol, 60ppm for SeO2 and 60ppm for CrO3 , respectively. The linear correlation between Gamma value and the concentration of toxic substances was obtained and EC50 wa calculated from the linear correlation. The free cells were shown to be more sensitive to toxic substances than cells immobilized on Sr-alginate and Ca-alginate. However, the linear regression curves were derived from the Sr-alginate immobilized cells indicating the immobilization method in s useful tool for monitoring of toxic substances under the more stable condition of bioluminescence.

• Journal of Microbiology and Biotechnology
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• 제16권8호
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• pp.1169-1173
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• 2006

Imaging ellipsometry (IE) for detection of binding of Escherichia coli O157:H7 (E. coli O157:H7) to an immunosensor is reported. A protein G layer, chemically bound to a self-assembled layer of 11-mercaptoundecanoic acid (11-MUA), was adopted for immobilization of monoclonal antibody against E. coli O157:H7 (Mab). The immobilization of antibody was investigated using surface plasmon resonance. To fabricate antibody spots on a gold surface, protein G solution was spotted onto the gold surface modified with an 11-MUA layer, followed by immobilizing Mab on the protein G spot. Ellipsometric images of the protein G spot, the Mab spot, and Mab spots with binding of E. coli O157:H7 in various concentrations were acquired using the IE system. The change of mean optical intensity of the Mab spots in the ellipsometric images indicated that the lowest detection limit was $10^3$CFU/ml for E. coli O157:H7. Thus, IE can be applied to an immunosensor for detection of E. coli O157:H7 as a detection method with the advantages of allowing label-free detection, high sensitivity, and operational simplicity.