• Toxicological Research
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• 제23권3호
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• pp.207-214
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• 2007

Chronic oxidative stress produced by exposure to environmental chemicals or pathophysiological states can lead animals to aging, carcinogenesis and degenerative diseases. Indirect antioxidative mechanisms, in which natural or synthetic agents are used to coordinately induce the expression of cellular antioxidant capacity, have been shown to protect cells and organisms from oxidative damages. Electrophile and free radical detoxifying enzymes, which were originally identified as the products of genes induced by cancer chemopreventive agents, are members of this protective system. The NFE2 family transcription factor Nrf2 was found to govern expression of these detoxifying enzymes, and screening for Nrf2-regulated genes has identified many gene categories involved in maintaining cellular redox potential and protection from oxidative damage as Nrf2 downstream genes. Further, studies using Nrf2-deficient mice revealed that these mutant mice showed more susceptible phenotypes towards exposure to environmental chemicals/carcinogens and in oxidative stress related disease models. With the finding that cancer chemopreventive efficacy of indirect antioxidants (enzyme inducers) is lost in the absence of Nrf2, a central role of Nrf2 in the antioxidative protective system has been firmly established. Promising results from cancer prevention clinical trials using enzyme inducers propose that pharmacological interventions that modulate Nrf2 can be an effective strategy to protect tissues from oxidative damage.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권2호
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• pp.96-99
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• 2006

In this study, we have attempted to determine the optimum concentration of inducers responsible for efficient laccase production by the white-rot fungus, Trametes sp. Variations in laccase activity were investigated with changing concentrations of 2,5-xylidine, syringaldazine, ABTS, and guaiacol. Enhancement of peak laccase activity was achieved via the combination of 2,5-xylidine with ABTS, syringaldazine, or guaiacol, resulting in increases of up to 359, 313, and 340%, respectively, as compared to control values. Among the tested inducers, the addition of 0.1mM of ABTS coupled with 1.0mM of 2,5-xylidine in the medium after 24 h of cultivation proved optimal with regard to laccase enzyme production.

• Journal of Microbiology and Biotechnology
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• 제21권12호
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• pp.1312-1321
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• 2011

Enzyme extracts of cellulase [filter paper cellulase (FPase) and carboxymethyl cellulase (CMCase)], chitinase, and chitosanase produced by Aspergillus niger NRRL-567 were evaluated. The interactive effects of initial moisture and different inducers for FP cellulase and CMCase production were optimized using response surface methodology. Higher enzyme activities [FPase $79.24{\pm}4.22$ IU/gram fermented substrate (gfs) and CMCase $124.04{\pm}7.78$ IU/gfs] were achieved after 48 h fermentation in solid-state medium containing apple pomace supplemented with rice husk [1% (w/w)] under optimized conditions [pH 4.5, moisture 55% (v/w), and inducers veratryl alcohol (2 mM/kg), copper sulfate (1.5 mM/kg), and lactose 2% (w/w)] (p<0.05). Koji fermentation in trays was carried out and higher enzyme activities (FPase $96.67{\pm}4.18$ IU/gfs and CMCase $146.50{\pm}11.92$ IU/gfs) were achieved. The nonspecific chitinase and chitosanase activities of cellulase enzyme extract were analyzed using chitin and chitosan substrates with different physicochemical characteristics, such as degree of deacetylation, molecular weight, and viscosity. Higher chitinase and chitosanase activities of $70.28{\pm}3.34$ IU/gfs and $60.18{\pm}3.82$ to $64.20{\pm}4.12$ IU/gfs, respectively, were achieved. Moreover, the enzyme was stable and retained 92-94% activity even after one month. Cellulase enzyme extract obtained from A. niger with chitinolytic and chitosanolytic activities could be potentially used for making low-molecular-weight chitin and chitosan oligomers, having promising applications in biomedicine, pharmaceuticals, food, and agricultural industries, and in biocontrol formulations.

• Toxicological Research
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• 제11권1호
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• pp.31-36
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• 1995

Cyclophosphamide (CP) must be enzymatically activated by cytochrome P450(CYP)-linked mixed-function oxidation pathway to be either mutagenic or teratogenic. Influences of alterations in hepatic mixed-function oxidase acitivity and glutathione (GSH) content on the embryotoxicity of CP were studied in rat whole embryo culture system. The embryotoxicity of CP was compared using rat S-9 fraction (S-9) pretreated with chemicals inducing different CYP isozymes, acetone (ACE), Aroclor 1254 (ARO), $\beta$-naphthoflavone (NAF) and phenobarbital (PHE). When 10.5 day embryos were cultured in the immediately centrifuged rat serum for 48 hrs using general gas char{ging schedule, CP$(40{\mu}g/ml)$ with S-9 induced by either NAF or PHE increased the incidence of realformations and significantly decreased embryonic growth compared with the non-induced S-9 group. ACE or ARO induced S-9 group showed no significant difference in embryonic growth. These data suggest that PB and/or NAF inducible CYP isoenzymes are mainly involved in the activation of CP. To examine the effect of GSH on the embryotoxicity of CP, 10.5 day embryos were exposed to CP and S-9 after preincubation with 10 mM of GSH for 3 hrs. In the GSH pretreated group the growth of embryos increased significantly compared with that of the untreated group, suggesting that GSH may protect embryos in culture from some toxic effects of CP.

• 한국미생물·생명공학회지
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• 제20권2호
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• pp.207-212
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• 1992

세라티아 균주의 배양으로부터 소염제로 사용되는 세라티오펩티다아제의 생산에 관한 연구를 수행하였다. 여러가지 탄소원, 질소원 및 유도제가 효소의 생산에 미치는 영향을 조사하였는데, 탄소원은 효소의 생산이나 세포성장에 좋지 못한 기질이었으며, 특히 citrate의 경우 균체성장량은 포도당과 거의 동일하였으나, 세라오펩티다제의 생산에 저해효과가 있음이 밝혀졌다. 세라티오펩티다아제는 아미노산인 leucine을 첨가해 주었을 때 그 생산되는 양이 크게 향상되었으며 leucine의 최적 농도는 0.03였다.

• Archives of Pharmacal Research
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• 제24권6호
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• pp.597-600
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• 2001

Based on the potential cancer chemoprebentive activity of resveratrol, a trihydroxystilbene with the induction of quinone reductase activeity this study was designed to determine if stilbene-related compounds were inducers of phase ll detoxifying metabolic enzyme quinone reductase (QR) in the mouse hepatoma Hepa 1c1c7 cells. Among the thirteen compounds tested, several compounds including 3,4,5,3',5'-pentamethoxy-trans-stibene were found to potentially induce QR activity in this cell line. In addition, substitution with 3-thiofurane ring instead of phenyl ring in the stilbene skeleton also exhibited potential induction of QR activity. This result will give primary information to design the potential inducers of QR activity in the stilbene analogs.

• 한국미생물·생명공학회지
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• 제19권3호
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• pp.281-289
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• 1991

Neurospora crassa는 성장이 끝나고 분화되는 과정에서 tyrosinase를 생산하며 아미노산류의 기질유사체, 반대사물질, 단백질 생합성 저해제 등에 의해 효소생산이 유도된다. 미생물 균체를 배양시키며 여러가지 유도물질을 사용하여 효소의 생합성을 유도시킨 결과 가장 적합한 유도물질은 cycloheximide였다. 이는 균체의 성장을 크게 저해하는 항생제의 일종이므로 효소 생합성을 최대화시키기 위한 최적의 농도가 존재하였으며, 유도물질의 농도가 일정한 경우에 효소 생산에 최적인 유도시간이 존재하였다.

• 한국약용작물학회지
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• 제15권6호
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• pp.437-443
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• 2007

홍삼의 물추출물을 장기간 흰쥐에 급여했을 때 흰쥐 간의 이물질대사효소 활성도 유도에 미치는 영향을 조사하였다. 홍삼 물추출물의 급여농도는 25 mg/kg body weight이었으며, 간의 이물질대사효소 유도제는 항경련제 PB (80 mg/kg)와 발암제 3-MC (20 mg/kg)을 사용하였다. 간에서 이물질대사에 관여하는 cytochrome P-450의 함량, cytochrome P-450 dependent monooxygenase인 ECOD와 BPDM, cytochrome P-450 reductase와 GST의 활성도는 PB와 3-MC 투여에 의해서 대조군과 홍삼투여군 모두 크게 증가되었다. 흰쥐의 나이가 3개월에서는 두 유도제를 투여했을 때 이물질대사효소의 활성은 대조군이 인삼투여군에 비해 상대적으로 더 많이 유도되었다. 그러나 12개월에서는 두 시험군 모두 유도정도가 감소하였으나 홍삼투여군은 그 활성도 감소정도가 대조군에 비해 상대적으로 크지 않았다. 한편 두 그룹 모두 이물질대사 효소 중 cytochrome $B_5$ 함량과 cytochrome $b_5$ reductase의 활성도는 PB와 3-MC 투여에 의해서 뚜렷한 차이를 보이지 않았다. 따라서 이러한 결과는 흰쥐에 홍삼의 장기간 급여는 간에서 효소유도제의 이물질대사효소유도 정도를 조절하여 무독화에 기여할 수 있다는 것을 의미한다.

• Mycobiology
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• 제45권4호
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• pp.409-420
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• 2017

Foliar sprays of three plant resistance inducers, including chitosan (CH), potassium sorbate (PS) ($C_6H_7kO_2$), and potassium bicarbonates (PB) ($KHCO_3$), were used for resistance inducing against Erysiphe cichoracearum DC (powdery mildew) infecting okra plants. Experiments under green house and field conditions showed that, the powdery mildew disease severity was significantly reduced with all tested treatments of CH, PS, and PB in comparison with untreated control. CH at 0.5% and 0.75% (w/v) plus PS at 1.0% and 2.0% and/or PB at 2.0% or 3.0% recorded as the most effective treatments. Moreover, the highest values of vegetative studies and yield were observed with such treatments. CH and potassium salts treatments reflected many compounds of defense singles which leading to the activation power defense system in okra plant. The highest records of reduction in powdery mildew were accompanied with increasing in total phenolic, protein content and increased the activity of polyphenol oxidase, peroxidase, chitinase, and ${\beta}$-1,3-glucanase in okra plants. Meanwhile, single treatments of CH, PS, and PB at high concentration (0.75%, 2.0%, and/or 3.0%) caused considerable effects. Therefore, application of CH and potassium salts as natural and chemical inducers by foliar methods can be used to control of powdery mildew disease at early stages of growth and led to a maximum fruit yield in okra plants.

• 한국식품과학회지
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• 제27권6호
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• pp.972-977
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• 1995

Quinone reductase(QR)를 포함한 2상효소계를 활성화시키는 성분들은 많은 동물실험에서 발암물질의 세포내 작용을 억제함으로서 항종양효과를 나타내는 것으로 보고되어 있다. 본 연구에서는 대표적인 농산부산물로서 미강, 밀기울, 탈지대두박, 두유박, 참깨박, 들깨박등 6종의 시료에 대한 암예방효과를 갖는 물질의 존재여부를 탐색하기 위하여, mouse hepatoma cell line(Hepalclc7 cells) 을 이용하여, quinone reductase활성유도 여부를 측정하였다. 참깨박과 들깨박의 80%메탄올 추출물은 0.5mg/ml 농도에서 강력한 QR 유도활성을 나타냈으며, 같은 농도에서 다른 시료들은 거의 QR 효소활성을 증가시키지 않았다. 한편 QR효소활성을 유도하는 성분을 찾아내기 위하여 일차적으로 TLC를 수행한 결과, 참깨박과 들깨박의 메탄올 추출물 가운데 사용한 전개용매(n-butanol : n-propanol : 2N ammonium hydroxide(10 : 60 : 30)에서 가장 빨리 이동하는 분획(Rf=0.70)이 유효성분을 함유하고 있음을 확인하였으며, 현재 활성성분의 동정이 진행중에 있다.