• 유체기계공업학회:학술대회논문집
• /
• 유체기계공업학회 2005년도 연구개발 발표회 논문집
• /
• pp.650-654
• /
• 2005

Computational and experimental studies on the forward-sweep inducer for the rocket-engine turbopump are presented in comparison with the conventional backward-sweep inducer. It is shown that back flows at the inlet decreases for forward-sweep inducers. And the low pressure region at the back flow are also decreased, which is assumed to promote the suction performance of the inducers. The backward-sweep inducer shows almost the same suction performance as that of the backward-sweep inducers although it has small inlet tip diameter and shorter length. And the efficiency of the forward-type inducer shows better results than the backward-sweep inducer due to the small size of backflows.

• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 2004년도 Annual Meeting of KSAP : New Drug Development from Natural Products
• /
• pp.21-35
• /
• 2004

Heme oxygenase (HO)-l catabolizes heme into three products: carbon monoxide, bilirubin, and free iron. HO-l serves as a protective gene by virtue of the anti-inflammatory, anti-apoptotic and anti-proliferative actions of one or more of these three products. HO-l can be regarded as a potential therapeutic target in a variety of oxidant-mediated and inflammatory diseases. In this respect, it would be valuable to develop potent and selective inducers of HO-1 for therapeutic use. Here, we have shown that 1,2,3,4,6-penta-O-galloyl-beta-D-glucose, catalposide and dehydrocostus lactone are potent inducers of HO-1 and exert cytoprotective and anti-inflammatory activities via HO-1-ependent machanism.

• Journal of Microbiology
• /
• 제39권3호
• /
• pp.229-231
• /
• 2001

Different DL-amino acids were studied as inducers of D-amino acid oxidase (DAAO) and for their influence on the growth of Trigonopsis variabilis. DL-amino acids with non-polar side groups were found to be the befit inducers of DAAO. Maximum increase in the growth of Trigonopsis variabilis (gram dry weight per liter culfure) was observed with DL-methionine (2.39 g/l) followed by DL-serine (2.22 g/l) and DL-alanine (2.21 g/l).

• Toxicological Research
• /
• 제19권3호
• /
• pp.235-240
• /
• 2003

The modification of CYP2E1 activity is of considerable interest because of its role in the metabolic activation of a variety of toxic chemicals. In the present studies, the time-course of changes in human CYP2E1 activities was determined after treatment with ethanol, glycerol, 4-methylpyrazole or isoniazid using intact HepG2 cells transfected by human CYP2E1. Hydroxylation of chlorzoxazone was chosen for the measurement of CYP2E1 activity. CYP2E1 protein levels were increased upon cultivation of cells in the presence of ethanol, glycerol, 4-methylpyrazole or isoniazid for 24 hr. After 24 hr cultivation, ethanol or glycerol increased CYP2E1 activities, whereas 4-methylpyrazole or isoniazid inhibited. This different effect of the chemical inducers on CYP2E1 activi-ties persisted to subsequent 24 hr. Competitive inhibition study suggested that 4-methylpyrazole or isoniazid has stronger binding affinity to CYP2E1 than ethanol or glycerol. These results demonstrate that different binding affinity of the chemical inducers to the active site of CYP2E1 plays important role in determining real CYP2E1 activity in intact cells after treatment with the chemical inducers. Present study would be helpful in precise understanding of human CYP2E1-mediated toxicity.

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

• 한국환경농학회지
• /
• 제27권4호
• /
• pp.362-367
• /
• 2008

The legume-rhizobia symbiosis is an important source of plant growth and nitrogen fixation for many agricultural systems. This study was conducted to investigate the effects of salinity stress on nitrogen fixation and growth of pea (Pisum sativum L.), which has antimutagenic activities against chemical mutagen, inoculated with R. leguminosarum bv. viciae cultured with additional plant-to-rhizobia signal compounds, naringenin (NA,15 uM), methyl-jasmonate (MJ, 50 uM) or both, under greenhouse conditions. Three salinity levels (0.6, 3.0 and $6.0\;dS\;m^{-1}$) were imposed at 3 days after transplanting and maintained through daily irrigations. Addition of signal compounds under non-stress and stress conditions increased dry weight, nodule numbers, leaf area and leaf greenness. The inducers increased photosynthetic rate under non-stress and stress conditions, by approximately 5-20% when compared to that of the non-induced control treatment. Under stress conditions, proline content was less in plants treated with plant-to-bacteria signals than the control, but phenol content was significantly increased, compared to that of the control. The study suggested that pre-incubation of bacterial cells with plant-to-bacteria signals could enhance pea growth, photosynthesis, nitrogen fixation and biomass under salinity stress conditions.

• 고려인삼학회:학술대회논문집
• /
• 고려인삼학회 2002년도 학술대회지
• /
• pp.262-265
• /
• 2002

• 한국유체기계학회 논문집
• /
• 제9권2호
• /
• pp.25-29
• /
• 2006

Computational and experimental studies on the forward-sweep inducer for the rocket-engine turbopump are presented in comparison with the conventional backward-sweep inducer. Computational results show that back flows at the inlet decrease in the case of forward-sweep inducers compared to the back-ward inducer. Moreover, the low pressure region at the back flow is decreased, which is presumed to improve the suction performance of the inducers. Experimental results show that the suction performance of the forward-sweep inducer is almost the same as that of the backward-sweep inducer although it has smaller inlet tip diameter and shorter length. The efficiency of the forward-type inducer is found better than that of the backward-sweep inducer due to the small size of back flows.

• Natural Product Sciences
• /
• 제10권5호
• /
• pp.248-251
• /
• 2004

Resveratrol has been reported to possess a variety of biological and pharmaceutical activities. Regardless of its beneficial effects on health, the amount of resveratrol in grapes is very low. In order to induce the resveratrol biosynthesis, the promoter region of a genomic fragment encoding the resveratrol synthase was isolated and a molecular switch was identified which provides us with defining biotic or abiotic inducers that transcriptionally up-regulate the gene expression involved in the resveratrol biosynthesis. We could successfully increase the amount of resveratrol in grapes up to 3-fold by using these environmental factors.

• Journal of Microbiology and Biotechnology
• /
• 제16권6호
• /
• pp.969-973
• /
• 2006

Stimulatory effects of three different intermediate metabolites (1-hydroxy-2-naphthoate, salicylate, and catechol) as potential inducers on phenanthrene degradation were investigated using two different bacteria (Pseudomonas putida ATCC 17484 and Burkholderia cepacia PB12). The relative induction capacity was high in the sequence of 1-hydroxy-2-naphthoate, salicylate, and catechol in both strains. The highest of up to 12 times increase of the induction was obtained by the addition of 1-hydroxy-2-naphthoate in the strain PB12, compared with the control where no exogenous inducer was added. The induction capacity of the potential inducers was closely related with the number of oxygenations required per electron equivalents in one mole of the inducer.