• Biomolecules & Therapeutics
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• v.26 no.6
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• pp.533-538
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• 2018

Nitric oxide (NO) mediates various physiological and pathological processes, including cell proliferation, differentiation, and inflammation. Protein S-nitrosylation (SNO), a NO-mediated reversible protein modification, leads to changes in the activity and function of target proteins. Recent findings on protein-protein transnitrosylation reactions (transfer of an NO group from one protein to another) have unveiled the mechanism of NO modulation of specific signaling pathways. The intracellular level of S-nitrosoglutathione (GSNO), a major reactive NO species, is controlled by GSNO reductase (GSNOR), a major regulator of NO/SNO signaling. Increasing number of GSNOR-related studies have shown the important role that denitrosylation plays in cellular NO/SNO homeostasis and human pathophysiology. This review introduces recent evidence of GSNO-mediated NO/SNO signaling depending on GSNOR expression or activity. In addition, the applicability of GSNOR as a target for drug therapy will be discussed in this review.

• Journal of Veterinary Clinics
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• v.16 no.1
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• pp.100-107
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• 1999

Apoptosis is now widely recognized as a common form of cell death and represents mechanism of cell clearance in many physiological situations where deletion of cells is required. In vivo administration of bacterial lipopolysaccharide (LPS) to Balb/c mice induced DNA fragmentation in the thymus. DNA fragmentation in the thymus was roughly dependent on the dose of LPS injected and reached the peak 18 hours after injection. This apoptosis in the thymus might be mediated due to LPS stimulant. DEN (diethylnitrosamine) has been shown to cause liver cancer in experimental animals and humans. The hepatic tumorigenesis was induced by ad libitum feeding of DEN only. It was suggested that DEN induced hepatic tumorgenesis in rat is a good reproducible model for studying biochemical and pathophysiological changes associated with the development of hepatic tumorigenesis and apoptosis.

• BMB Reports
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• v.39 no.3
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• pp.335-338
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• 2006

Methylglyoxal (MG) is an endogenous physiological metabolite which is present in increased concentrations in diabetics. MG reacts with the amino acids of proteins to form advanced glycation end products. In this in vitro study, we investigated the effect of MG on the structure and function of ceruloplasmin (CP) a serum oxidase carrier of copper ions in the human. When CP was incubated with MG, the protein showed increased electrophoretic mobility which represented the aggregates at a high concentration of MG (100 mM). MG-mediated CP aggregation led to the loss of enzymatic activity and the release of copper ions from the protein. Radical scavengers and copper ion chelators significantly prevented CP aggregation. CP is an important protein that circulates in plasma as a major copper transport protein. It is suggested that oxidative damage of CP by MG may induce perturbations of the copper transport system and subsequently lead to harmful intracellular condition. The proposed mechanism, in part, may provide an explanation for the deterioration of organs in the diabetic patient.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.57-63
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• 1997

Animal and clinical investigations have shown that fluoroquinolones, new quinolone antibacterial agents (NQs), are well absorbed across the intestinal tract, with a bioavailability of 60-90% after oral administration. Although some types of carrier-mediated intestinal transport mechanisms have been reported for enoxacin (ENX), ofloxacin (OFLX) and sparfloxacin (SPFX), recent results using a human intestinal epithelial cell line, Caco-2, indicated a passive or nonsaturable transport of SPFX, one of the most hydrophobic NQs. The mechanism underlying the intestinal absorption of NQs is still largely unknown. The distribution of NQs into peripheral tissues including erythrocytes is very rapid and their tissue-to-plasma concentration ratios (Kp) are considerably larger than those of inulin (an extracellular fluid space marker), in spite of almost complete ionization of NQs at the physiological pH. Our findings suggest that OFLX and lomefloxacin (LFLX) are taken up by rat erythrocytes via a transport system common to that of a water-soluble vitamin, nicotinic acid.

• Microbiology and Biotechnology Letters
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• v.28 no.1
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• pp.1-7
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• 2000

The bacterial strain JW-2 which conferred resistance against paraquat (1,1'-dimethyl-4,4'-bipyridinium dichloride) was isolated from soil. The strain was identified as an Ochrobactrum anthropi based on its morphological, physiological, biological and fatty acid composition, and was designated as Ochrobactrum anthropi JW-2. We compard paraquat resistance of O. anthropi JW-2 with Escherichia coli J105. In the presence of 100mM paraquat, E. coli JM105 was not grown whereas the growth rate of O. anthropi was about 70% of control. We compared the sensitivity of O. anthropi JW-2 and E. coli J105 to redox-cycling compounds such as paraquat, plumbagin or menadione, which are known to exacebate wuperoxide generation. O. anthropi JW-2 did not show cross-resistance to plumbagin or menadione. superoxide dismutase activity was increased in paraqunt-treated E. coli JM105 while it was not increased in O.anthropi JW-2. These results suggest that the mechanism of paraquat resistance in O.anthropi JW-2 is probably due to selectively decreased permeability toward paraquat by membrane protein.

• Journal of Korean Medical classics
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• v.18 no.4 s.31
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• pp.49-59
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• 2005

On the importance of brain, Nei Ching has many descriptions, but it has been 3,000 years since the theory was issued that brain should be considered as a viscera. Nowadays scientists rush more studies on brain in international scientific field, Eastern medicine is to be required for the solution of it. This study is on the identical pathological mechanism between Simpo and brain based on my researches on senil dimentia through continued reports last 15 years. A psychosis is caused by stress and abnormality of neurotransmitter on brain, for which is caused by seven emotions and pathological material on Simpo in Pyun Jahk Simseo, so it shows Simpo is brain clearly. Therefore Simpo is no more intangible organ but brain, Samcho which has been debated similarly for thousands of years in the orient is no more intangible but spinal nerve system on central nerve with its structure and physiological points, and both two organs are composed of inside and outside relationship in Eastern medicine, I report hereby today.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.1-10
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• 2004

Many bacteria monitor their population density and control the expression of specialized gene sets in response to bacterial cell density based on a mechanism referred to as quorum sensing. In all cases, quorum sensing involves the production and detection of extracellular signaling molecules, auto inducers, as which Gram-negative and Gram-positive bacteria use most prevalently acylated homoserine lactones and processed oligo-peptides, respectively. Through quorum-sensing communication circuits, bacteria regulate a diverse array of physiological functions, including virulence, symbiosis, competence, conjugation, antibiotic production, motility, sporulation, and biofilm formation. Many pathogens have evolved quorum-sensing mechanisms to mount population-density-dependent attacks to over-whelm the defense responses of plants, animals, and humans. Since these AHL-mediated signaling mechanisms are widespread and highly conserved in many pathogenic bacteria, the disruption of quorum-sensing system might be an attractive target for novel anti-infective therapy. To control AHL-mediated pathogenicity, several promising strategies to disrupt bacterial quorum sensing have been reported, and several chemicals and enzymes have been also investigated for years. These studies indicate that anti-quorum sensing strategies could be developed as possible alternatives of antibiotics.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.457-460
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• 2014

At central synapses, activity-dependent synaptic plasticity has a crucial role in information processing, storage, learning, and memory under both physiological and pathological conditions. One widely accepted model of learning mechanism and information processing in the brain is Hebbian Plasticity: long-term potentiation (LTP) and long-term depression (LTD). LTP and LTD are respectively activity-dependent enhancement and reduction in the efficacy of the synapses, which are rapid and synapse-specific processes. A number of recent studies have a strong focal point on the critical importance of another distinct form of synaptic plasticity, non-Hebbian plasticity. Non-Hebbian plasticity dynamically adjusts synaptic strength to maintain stability. This process may be very slow and occur cell-widely. By putting them all together, this mini review defines an important conceptual difference between Hebbian and non-Hebbian plasticity.

• The Korean Journal of Physiology
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• v.10 no.2
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• pp.1-10
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• 1976

The action of acetylcholine on the sodium plus potassium activated ATPase activity in the rabbit red cell membrane has been investigated and the experiments were also designed to determine the mechanism of action of acetylcholine on the ATPase activity. The following results were observed. 1. The activity of the NaK ATPase from red cell membrane is inhibited by acetylcholine. 2. The ratio of inhibition of NaK ATPase by acetylcholine is decreased by raising the potassium concentration, and is increased by raising the sodium concentration. 3. The ATPase activity is increased by small amounts of calcium but inhibited by larger amounts. The ratio of inhibition of the enzyme by acetylcholine is increased by raising the calcium concentration. 4. The inhibitory action of acetylcholine on the NaK ATPase activity was not related to the sulfhydryl group of cysteine, the hydroxyl group of threonine, or the carboxyl group of aspartic acid. 5. The inhibitory action of acetylcholine on the ATPase activity is due to amino group of the enzyme of NaK ATPase.

• Journal of Plant Biology
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• v.33 no.2
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• pp.105-110
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• 1990

Physiological gradient of IAA-oxidizing enzyme activities was investigated in order to elucidate the mechanism of shoot differentiation in Cymbidium sp. (‘Jungfrau’) protocorms by using phenolic compounds (2, 4-dichlorophenol, catechol), auxin-inhibitors (PCIB, TIBA), and hormones (GA3, ABA, BA). The activity of IAA oxidase was decreased in protocorms treated with catechol decreased the catalytic activity of IAA oxidase or TIBA but this enzyme activity was increased after a temporary decrease at initial stages in the presence of 2, 4-dichlorophenol or PCIB. The activity of IAA oxidase in BA-treated protocorms (white and crown gall-like) was the highest of all. However, the catalytic activity of peroxidase increased after a temporary decrease at initial period. These results suggest that shoot differentiation and growth may be influenced by effective IAA levels in the protocorms causing IAA-oxidizing enzyme and phenolic compounds.