• Journal of the Optical Society of Korea
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• 제20권1호
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• pp.199-203
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• 2016

An enzyme-free optical method is proposed for estimating high concentrations of glucose in a glucose-lactose mixture, based on a predictive equation that takes advantage of the reflective optical power observed at two discrete wavelengths. Compared to the conventional absorption spectroscopy method based on Beer's Law, which is mainly valid for concentrations below hundreds of mg/dL, the proposed scheme, which relies on reflection signals, can be applied to measure higher glucose concentrations, of even several g/dL in a glucose-lactose mixture. Two probe wavelengths of 1160 and 1300 nm were selected to provide a linear relationship between the reflective power and pure glucose/lactose concentration, where the relevant linear coefficients were derived to complete the predictive equation. Glucose concentrations from 2 to 7 g/dL in a glucose-lactose mixture were efficiently estimated, using the established predictive equation based on monitored reflective powers. The standard error of prediction was 1.17 g/dL.

• Journal of Plant Biology
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• 제12권2호
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• pp.7-14
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• 1969

Dunaliella tertiolecta did not show any increase in respiration rate when supplied with glucose, glycerol, sucrose, L-alanine, acetate, pyruvate and succinate. This was in contrast to Chlorella pyrenoidosa, which, under identical conditions, showed significant increase when supplied with glucose or acetate but not with the other compounds. Production of 14CO2 from added 14C-glucose in D. tertiolecta was lower than the other 14C-labelled substrates: L-alinine, glycerol, succinate, but higher than 14C-sucrose addition. And it was also lower than C. pyrenoidosa experiments which was added 14C-glucose as a substrate. Light reduced amounts of labelled carbon dioxide from 14C-glucose or 14C-acetate and increased incorporation of 14C from the substrates to cell materials in either D. tertiolecta or C. pyrenoidosa. The contribution of 14C from 14C-glucose to 14CO2 in cell-free system of D. tertiolecta were much higher than in whole cell suspension. It was contrast to C. pyrenoidosa which were showed reduction of 14CO2 production in cell-free systems than whole cell suspensions. When cell-free systems of D. tertiolecta and C. pyrenoidosa were supplied with ATP, NAD, NADP or/and hexokinase, it was remarkably increased production of 14CO2 from the substrates than the control. It was concluded that the low ability of D. tertiolecta to metabolize glucose were caused by the impermeability of the cell membrane to glucose and were not due to deficiencies of enzyme systems concerning glucose metabolism. In the cell-free systems, it seemed to be more active pentose phosphate pathway than glycolytic pathway in D. tertiolecta.

• BMB Reports
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• 제37권4호
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• pp.503-506
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• 2004

Glucose-1-phosphate uridylyltransferase from E. coli K12 was used to convert uridine-5'-triphosphate and glucose-1-phosphate to UDP-D-glucose. The conversion was efficient and completed within 5 minutes under the employed conditions. In addition, thymidine-5'-monophosphate kinase and acetate kinase were proven to be non-specific, converting udridine-5'-monophosphate to uridine-5'-triphosphate with 55% conversion after 6 h, which was much slower than the production of TTP under the same conditions (complete conversion within one hour). Since these two reactions could proceed under the same conditions, a one-pot synthesis of UDP-D-glucose with ATP regeneration was designed from easily available starting materials, and conversion up to 40% by HPLC peak integration was achieved given a reaction time of 4 h.

• Journal of Animal Science and Technology
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• 제51권6호
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• pp.511-520
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• 2009

The purpose of this study was to investigate effects of increased levels of eugenol, thymol and malate on pH and the concentrations of VFA, lactate and ammonia-N during in vitro ruminal incubation. One Hanwoo beef steer (741 kg) fitted with a rumen cannula was used and fed 0.5 kg/day rice straw and 10 kg/day corn-based concentrate (ratio of concentrate to rice straw = 95 : 5 on DM basis). Three different doses of thymol, eugenol and malate were used. Treatments of the experiment were as follows: Treatments of thymol were control (1g D-glucose/40ml), T1 (1g D-glucose + 40 mg thymol/40 ml), T2 (1g D-glucose + 50 mg thymol/40 ml) and T3 (1g D-glucose + 60 mg thymol/40 ml). Treatments of eugenol were control (1g D-glucose/40 ml), E1 (1g D-glucose + 55 mg eugenol/40 ml), E2 (1g D-glucose + 65 mg eugenol/40 ml) and E3 (1g D-glucose + 75 mg eugenol/40 ml). Treatments of malate were control (1g D-glucose/40ml), M1 (1g D-glucose + 25 mg malate/40ml), M2 (1g D-glucose + 50 mg malate/40 ml) and M3 (1g D-glucose + 100 mg malate/40 ml). The results of this study showed that eugenol and thymol have improved stability of the ruminal fermentation by decreasing lactic acid concentration and increasing ruminal pH. However, it inhibited the production of total VFA, acetate and propionate. Malate also improved stability of the ruminal fermentation by decreasing lactic acid concentration and increasing ruminal pH, but it had a very little effect on ruminal lactate concentrations and pH. On the other hand, malate did not decrease the concentrations of total VFA, acetate and propionate. Therefore, at the low ruminal pH expected in high-concentrate diets, thymol, eugenol, and malate are potentially useful in Hanwoo finishing diets. Further studies are necessary for determining the effectiveness of these additives on in vivo rumen fermentation and animal performance in Hanwoo finishing steers.

• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.665-672
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• 2004

D-Ribose is a five-carbon sugar used for the commercial synthesis of riboflavin, antiviral agents, and flavor enhancers. Batch fermentations with transketolase-deficient B. subtilis JY1 were carried out to optimize the production of D-ribose from xylose. The best results for the fermentation were obtained with a temperature of $37^{\circ}C$ and an initial pH of 7.0. Among various sugars and sugar alcohols tested, glucose and sucrose were found to be the most effective for both cell growth and D-ribose production. The addition of 15 g/l xylose and 15 g/l glucose improved the fermentation performance, presumably due to the adequate supply of ATP in the xylose metabolism from D-xylulose to D-xylulose-5-phosphate. A batch culture in a 3.7-1 jar fermentor with 14.9 g/l xylose and 13.1 g/l glucose resulted in 10.1 g/l D-ribose concentration with a yield of 0.62 g D-ribose/g sugar consumed, and 0.25 g/l-h of productivity. Furthermore, the sugar utilization profile, indicating the simultaneous consumption of xylose and glucose, and respiratory parameters for the glucose and sucrose media suggested that the transketolase-deficient B. subtilis JY1 lost the glucose-specific enzyme II of the phosphoenolpyruvate transferase system.

• 동아시아식생활학회지
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• 제7권1호
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• pp.35-39
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• 1997

Studies on the glucose isomerase produced by alkalophilic Streptomyces sp. B-2. Glucose Isomerase (E. C. 5.3.1.5) which reversibly catalyzes reaction between D-glucose and D-fructose was demonstrated in cell free extracts of alkalophilic Streptomyces sp. B-2 isolated form soil. The maximum enzyme activity was found at glucose concentration 4(g/$\ell$) , xylose concentration 6(g/$\ell$), magnesium ion 1.0(g/$\ell$), yeast extract concentration 2.0(g/$\ell$), peptone concentration 3(g/$\ell$).

• The Korean Journal of Physiology and Pharmacology
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• 제17권6호
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• pp.493-497
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• 2013

We have recently demonstrated that some anti-diabetic drugs such as biguanide and thizolidinediones administered centrally modulate the blood glucose level, suggesting that orally administered anti-diabetic drugs may modulate the blood glucose level by acting on central nervous system. The present study was designed to explore the possible action of another class of anti-diabetic drugs, glinidies, administered centrally on the blood glucose level in ICR mice. Mice were administered intracerebroventricularly (i.c.v.) or intrathecally (i.t.) with 5 to $30{\mu}g$ of repaglinide or nateglinide in D-glucose-fed and streptozotocin (STZ)-treated models. We found that i.c.v. or i.t. injection with repaglinide dose-dependently attenuated the blood glucose level in D-glucose-fed model, whereas i.c.v. or i.t. injection with nateglinide showed no modulatory action on the blood glucose level in D-glucose-fed model. Furthermore, the effect of repaglinide administered i.c.v. or i.t. on the blood glucose level in STZ-treated model was studied. We found that repaglinide administered i.c.v. slightly enhanced the blood glucose level in STZ-treated model. On the other hand, i.t. injection with repaglinide attenuated the blood glucose level in STZ-treated model. The plasma insulin level was enhanced by repaglinide in D-glucose-fed model, but repaglinide did not affect the plasma insulin level in STZ-treated model. In addition, nateglinide did not alter the plasma insulin level in both D-glucose-fed and STZ-treated models. These results suggest that the anti-diabetic action of repaglinide appears to be, at least, mediated via the brain and the spinal cord as revealed in both D-glucose fed and STZ-treated models.

• 생약학회지
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• 제26권4호
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• pp.327-336
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• 1995

Twelve phenolic components were isolated from the aqueous acetone extract of the leaf of Cornus controversa H. (Cornaceae). On the basis of chemical and spectroscopic evidence, the structures of these components were established as gallic acid, $1-O-galloyl-{\beta}-{_D}-glucose$, $1,6-di-O-galloyl-{\beta}-{_D}-glucose$, $1,2,3-tri-O-galloyl-{\beta}-{_D}-glucose$, $1,2,6-tri-O-galloyl-{\beta}-{_D}-glucose$, 3,4,6-tri-O-galloyl ${_D}-glucose$, eugeniin, gemine D, quercetin, quercitrin, hyperoside and rutin.

• The Korean Journal of Physiology and Pharmacology
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• 제18권1호
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• pp.41-46
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• 2014

The possible roles of spinal histamine receptors in the regulation of the blood glucose level were studied in ICR mice. Mice were intrathecally (i.t.) treated with histamine 1 (H1) receptor agonist (2-pyridylethylamine) or antagonist (cetirizine), histamine 2 (H2) receptor agonist (dimaprit) or antagonist (ranitidine), histamine 3 (H3) receptor agonist (${\alpha}$-methylhistamine) or antagonist (carcinine) and histamine 4 (H4) receptor agonist (VUF 8430) or antagonist (JNJ 7777120), and the blood glucose level was measured at 30, 60 and 120 min after i.t. administration. The i.t. injection with ${\alpha}$-methylhistamine, but not carcinine slightly caused an elevation of the blood glucose level. In addition, histamine H1, H2, and H4 receptor agonists and antagonists did not affect the blood glucose level. In D-glucose-fed model, i.t. pretreatment with cetirizine enhanced the blood glucose level, whereas 2-pyridylethylamine did not affect. The i.t. pretreatment with dimaprit, but not ranitidine, enhanced the blood glucose level in D-glucose-fed model. In addition, ${\alpha}$-methylhistamine, but not carcinine, slightly but significantly enhanced the blood glucose level D-glucose-fed model. Finally, i.t. pretreatment with JNJ 7777120, but not VUF 8430, slightly but significantly increased the blood glucose level. Although histamine receptors themselves located at the spinal cord do not exert any effect on the regulation of the blood glucose level, our results suggest that the activation of spinal histamine H2 receptors and the blockade of spinal histamine H1 or H3 receptors may play modulatory roles for up-regulation and down-regulation, respectively, of the blood glucose level in D-glucose fed model.

• 대한의생명과학회지
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• 제9권4호
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• pp.177-181
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• 2003

The baculovirus/Spodoptera frugiperda (Sf) cell system has become popular for the production of large amounts of the human erythrocyte glucose transporter, GLUT1, heterologously. However, it was not possible to show that the expressed transporter in insect cells could actually transport glucose. The possible reason for this was that the activity of the endogenous insect glucose transporter was extremely high and so rendered transport activity resulting from the expression of exogenous transporter very difficult to detect. Sf21-AE cells are commonly employed as the host permissive cell line to support the baculovirus AcNPV replication and protein synthesis. The cells grow well on TC-100 medium that contains 0.1 % D-glucose as the major carbon source, strongly suggesting the presence of endogenous glucose transporters. However, unlike the human glucose transporter, very little is known about properties of the endogenous sugar transporter(s) in insect cells. Thus, the uptake of 2-deoxy-D-glucose (2dGlc) by Sf21-AE cells and the inhibition of 2dGlc transport in the insect cells by fructose and cytochalasin B were investigated in the present work. The binding assay of cytochalasin B was also performed, which could be used as a functional assay for the endogenous glucose transporter(s) in the insect cells. Sf21-AE cells were infected with the recombinant virus AcNPV-GT or no virus, at a multiplicity of infection (MOI) of 5. Infected cells were resuspended in PBS plus and minus 300 mM fructose, and plus and minus 20 $\mu$M cytochalasin B for use in transport assays. Uptake was measured at 28$^{\circ}C$ for 1 min, with final concentration of 1 mM deoxy-D-glucose, 2-[1,2-$^3$H]- or glucose, L-[l,$^3$H]-, used at a specific radioactivity of 4 Ci/mol. The results obtained demonstrated that the sugar uptake in uninfected cells was stereospecific, and was strongly inhibited by fructose but only poorly inhibitable by cytochalasin B. It is therefore suggested that the Sf21-AE glucose transporter has very low affinity for cytochalasin B, a potent inhibitor of human erythrocyte glucose transporter.