• Journal of Microbiology and Biotechnology
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• 제16권6호
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• pp.993-998
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• 2006

We earlier suggested a hierarchical regulatory network using defined modeling symbols and weights in order to improve the flux balance analysis (FBA) with regulatory events that were represented by if-then rules and Boolean logic. In the present study, the simulation results of the models, which were developed and improved from the previou model by incorporating a hierarchical regulatory network into the FBA, were compared with the experimental outcome of an aerobic batch growth of E. coli on glucose and tryptophan. From the experimental result, a diauxic growth curve was observed, reflecting growth resumption, when tryptophan was used as an alternativee after the supply of glucose was exhausted. The model parameters, the initial concentration of substrates (0.92 mM glucose and 1 mM tryptophan), cell density (0.0086 g biomass/1), the maximal uptake rates of substrates (5.4 mmol glucose/g DCW h and 1.32 mmol tryptophan/g DCW h), and lag time (0.32 h) were derived from the experimental data for more accurate prediction. The simulation results agreed with the experimental outcome of the temporal profiles of cell density and glucose, and tryptophan concentrations.

• Microbiology and Biotechnology Letters
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• 제20권5호
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• pp.588-596
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• 1992

The fermentation characteristics of ethanol production by the use of immobilized Zymomonas mobilis KCTC 1534 cells were investigated in terms of formation factors such as substrate and product concentration. In batch fermentation, the maximum values of specific ethanol productivity, specific substrate uptake rate, ethanol yield, and glucose conversion rate were $29.14g/{\ell}{\cdot}h$, $60.24g/{\ell}{\cdot}h$, 0.48g/g, and 98.4%, respectively, with 17% glucose medium, and its ethanol productivity was $2.91g/{\ell}{\cdot}h$ in the case of 25 hour fermentation time. Repeated batch fermentation was possible for 30 days with 2.24-$2.94g/{\ell}{\cdot}h$ ethanol productivity. In semicontinuous fermentation, the maximum ethanol productivity was shown to be $15.7g/{\ell}{\cdot}h$ at $0.36h^{-1}$ effective dilution rate with 17% glucose concentration. In this case, ethanol yield coefficient and glucose conversion rate were 0.39 g/g, 64.7%, respectively.

• YAKHAK HOEJI
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• 제55권4호
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• pp.301-308
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• 2011

Diabetes has been one of major health risks in industrialized countries. AMP-activated protein kinase (AMPK) has been focused as a novel therapeutic target for the treatment of metabolic syndromes, because AMPK increases glucose uptake through independent insulin signal pathway. In this study, we investigated the anti-diabetic effect of Angelica gigas Nakai extract (AGNEX), a mixture of decursin and decursinol angelate (53 : 47), decursin and decursinol angelate on blood glucose, glucose transport (GLUT) and AMPK expression levels in streptozotocin (STZ)-induced diabetic rats. To induce diabetes, 50 mg/kg of STZ was injected via i.v. route and AGNEX 2 mg/kg (STZ+AG), decursin 2 mg/kg (STZ+D), decursinol angelate 2 mg/kg (STZ+DA), and metformin 100 mg/kg (STZ+M) were administered orally for 21 days. STZ+DA group showed a significant decrease in fasting blood glucose levels compared to the other groups. Decursinol angelate significantly upregulated expression of glucose transporter 4 (GLUT4) and phosphorylation of AMPK (p-AMPK) in skeletal muscle of rats. In pancreas of rats, decursinol angelate significantly increased expression of GLUT2 through down-regulation of p-AMPK. In addition to the result of pancreatic islets morphology, AGNEX, decursin, decursinol angelate, and metformin treated group recovered ${\beta}$-cell damage by hyperglycemia. These results indicate that decursinol angelate might be a potential anti-diabetic agent and AGNEX could be useful in the treatment of diabetes mellitus.

• Biomolecules & Therapeutics
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• 제12권2호
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• pp.74-78
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• 2004

Paecilomyces tenuipes, a caterpillar fungus, contains many health-promoting ingredients. Recent reports indicate that consumption of P. tenuipes helps reducing blood sugar content for diabetes. Mechanism for reduction in the circulatory sugar content, however, still remains least understood. Methanolic extraction of P. tenuipes (MPT) was prepared and acetoxyscirpendiol (ASD) was subsequently purified limn MPT. Glucose transporter-1 (GLUT-1) was expressed in the Xenopus oocytes and the effect of MPT or ASD on the expressed GLUT-1 was analyzed according to the uptake of 2-dideoxy-D-glucose (2-DOG). MPT was shown to inhibit GLUT-1 activity significant1y compared to the non-treated control. In the presence of ASD and its derivatives, GLUT-1 activity was greatly inhibited in a dose-dependent manner. Among ASD and its derivatives, AS-1 showed most significant inhibition. Taken together, these results strongly indicate that ASD in P. tenuipes may serve as a functional substance in lowering blood sugar in the circulatory system. ASD and its derivatives can be utilized as inhibitors of GLUT-1.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제11권sup1호
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• pp.149-152
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• 2008

Obesity tracks from childhood into adulthood, and the persistence of obesity rises with age among obese children. Obesity are independent risk factors for increased morbidity and mortality throughout the lifecycle. Obese individuals develop resistance to the cellular actions of insulin, characterized by an impaired ability of insulin to inhibit glucose output from the liver and to promote glucose uptake in fat and muscle. Insulin resistance is a key etiological factor for type 2 diabetes mellitus, dyslipidemia, hypertension, nonalcoholic steatohepatitis, polycystic ovarian syndrome.

• The Plant Pathology Journal
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• 제20권1호
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• pp.1-6
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• 2004

The diseases caused by Xylella fastidiosa are associated with aggregation of the bacteria m xylem vessels, formation of a gummy matrix and subsequent blockage of water uptake. In the closely related pathogen, Xanthomonas campestris, xanthan gum is known to be an important virulence factor, probably contributing to bacterial adhesion, aggregation and plugging of xylem. Xanthan gum, produced by X. campestris, is an extra-cellular polysaccharide consisting of a cellulose backbone ($\bate$-1,4-linked D-glucose) with trisaccharide side chains composed of mannose, glucuronic acid and mannose attached to alternate glucose residues in the backbone. We had constructed a mutant of X. campestris lacking gumI gene that is responsible for adding the terminal mannose for producing modified xanthan gum which is similar to xanthan gum fromX. fastidiosa. The modified xanthan gum degrading endgphytic bacterium Acineto-bacter johnsonii GX123 isolated from the oleander infected with leaf scorch disease.

• Biomolecules & Therapeutics
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• 제16권4호
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• pp.370-376
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• 2008

Ginsenoside Rp1 (G-Rp1) is a ginseng saponin derivative with chemopreventive and anti-cancer activities. In this study, we examined the regulatory activity of G-Rp1 on the functional activation of macrophages. G-Rp1 remarkably inhibited TNF-$\alpha$ production, LPS-induced cell cytotoxicity, NO production, ROS generation, and phagocytic uptake from lipopolysacchride (LPS)-activated RAW264.7 cells. According to structural feature study using several G-Rp1 analogs, two carbohydrates (glucose-glucose) at R1 position were observedto be highly effective, compared to other structural derivatives. Although the inhibitory activities of G-Rp1 on macrophage functions were not remarkable, several points that G-Rp1 was known to be safe, and that this compound was orally effective, suggest that G-Rp1 may be beneficial in treating macrophage-mediated immunological diseases.

• Journal of Ginseng Research
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• 제18권1호
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• pp.17-24
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• 1994

Effect of ginsenoside mixture, ginsenoside $Rb_1$,$Rb_2$,$Rg_1$ and the fat soluble fraction of the roots of Panax ginseng C.A. Meyer on the activity of glucokinase (GK) in vitro has been observed and found that GK activity was increased about 15c1c at the concentration of ginsenoside mixture and/or the fat soluble fraction being $10^{-7}$,$10^{-5}$%. It was also observed that glucose uptake by rat liver was increased in the presence of either ginsenoside mixture or the fat soluble fraction by perfusion technique. Ginsenoside mixture stimulated various enzymes related to glucose metabolism, however, both ginsenoside mixture and the fat soluble fraction did not stimulate GK activity as expected. Primary culture of liver cells showed that the ginsenoside mixture and the fat soluble fraction increased GK activity significantly and they stimulated the GK activity synergistically in the co-presence of insulin.

• Journal of Pharmaceutical Investigation
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• 제20권4호
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• pp.223-228
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• 1990

The contribution of endogenous transport systems to the blood-brain barrier (BBB) transport of basic and acidic drugs was studied by using a carotid injection technique in rats and an isolated bovine cerebrovascular disease state were compared between the normotensive rats (WKY) and stroke-prone spontaneously hypertensive rats (SHRSP) which have been well established as an animal model with pathogenic similarities to humans. Basic drugs such as eperisone, thiamine and scopolamine inhibited, in a concentration dependent manner the in vivo uptake of $[{^3}H]choline$ through BBB, whereas amino acids and acidic drugs such as salicylic acid and valproic acid did not inhibit the uptake. The uptake of $[^3H]choline$ by B-CAP increased with time and showed a remarkable temperature dependency. The uptake of $[^3H]choline$ by B-CAP showed the very similar inhibitory effects as observed in the in vivo brain uptake, and was competitively inhibited by a basic drug, eperisone. The in vivo BBB uptakes of $[^3H]acetic$ acid and $[^{14}C]salicylic$ acid were dependent on pH of the injectate and the concentration of drugs. Several acidic drugs such such as salicylic acid, benzoic acid and valproic acid inhibited the in vivo uptake of $[^3H]acetic$ acid, whereas amino acid, choline and a basic drug such as eperisone did not inhibit the uptake. The uptake of acetic acid by B-CAP was competitively inhibited by salicylic acid. The permeability surface area product (PS) through BBB for $[^3H]choline$ in SHRSP was significantly lower than that in WKY. The concentration of choline in the brain dialysate in SHRSP was about half of that in WKY, while no significant difference was observed in the plasma concentration of choline between SHRSP and WKY. No significant difference was observed in the transport of monocarboxylic acids, glucose and neutral amino acid through BBB between SHRSP and WKY. From these results, it was concluded that BBB transport system of choline contributes to the transport of basic drugs through BBB, that acidic drugs can be transported via a moncarboxylic acid BBB transport system and that the specific dysfuntion of the BBB choline transport in SHRSP was ascribed to the reduction of the maximum velocity of choline concentration in the brain interstitial fluids.

• 대한핵의학회:학술대회논문집
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• 대한핵의학회 2004년도 추계학술대회 및 총회
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• pp.412.1-412.1
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• 2004