• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.119.1-119
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• 2003

The glyoxysomal nature of microbodies was determined in Botryosphaeria dothidea hyphae based on morphology and in situ enzyme characteristics by transmission electron microscopy and cytochemistry. Bound by a single membrane, microbodies had a homogeneous matrix and varied in size ranging from 200 to 400 m in diameter. Microbodies had crystalline inclusion(s) which consisted of parallel arrays of fine tubules in their matrices. Microbodies and lipid globules were frequently placed in close association with each other, forming microbody-lipid globule complexes in hyphae. The cytochemical activities of catalase and malate synthase were localized in matrices of microbodies, showing intense electron-density of the organelle. In addition, the immunogold labeling detected the presence of catalase in multivesicular bodies and hyphal cell walls as well as in matrices and crystalline inclusions of microbodies, supporting the enzyme secretion through cell walls. Meanwhile, isocitrate Iyase was localized only in matrices of microbodies. These results suggest that microbodies, particularly complexed with lipid globules, in the fungal hyphae are functionally defined as glyoxysomes, where glyoxysomal enzymes are biochemically active for the glyoxylate cycle to be a metabolic pathway in gluconeogenesis. (Mycology and Fugus Diseases)

• BMB Reports
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• v.51 no.9
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• pp.429-436
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• 2018

Fructose in the form of sucrose and high fructose corn syrup is absorbed by the intestinal transporter and mainly metabolized in the small intestine. However, excess intake of fructose overwhelms the absorptive capacity of the small intestine, leading to fructose malabsorption. Carbohydrate response element-binding protein (ChREBP) is a basic helix-loop-helix leucine zipper transcription factor that plays a key role in glycolytic and lipogenic gene expression in response to carbohydrate consumption. While ChREBP was initially identified as a glucose-responsive factor in the liver, recent evidence suggests that ChREBP is essential for fructose-induced lipogenesis and gluconeogenesis in the small intestine as well as in the liver. We recently identified that the loss of ChREBP leads to fructose intolerance via insufficient induction of genes involved in fructose transport and metabolism in the intestine. As fructose consumption is increasing and closely associated with metabolic and gastrointestinal diseases, a comprehensive understanding of cellular fructose sensing and metabolism via ChREBP may uncover new therapeutic opportunities. In this mini review, we briefly summarize recent progress in intestinal fructose metabolism, regulation and function of ChREBP by fructose, and delineate the potential mechanisms by which excessive fructose consumption may lead to irritable bowel syndrome.

• YAKHAK HOEJI
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• v.7 no.1
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• pp.18-25
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• 1963

We have studied on the effects of Panax Ginseng on the carbohydrate metabolism of rat. Ginseng does not so much effect on the body weight of the nutrition diet groups, but effects much on the carbohydrate deficient diet groups; it remarkably inhibited the decrease of body weight. Liver glycogen, both in the nutrition and carbohycdrate deficient diet groups, is higher than that of the control. Particularly, the increase of the glycogen is eminent is the nutrition diet-ginseng administered group. In the nutrition diet group, the blood sugar level of ginseng-adminstered rats is the higher, while, in the carbohydrate deficient diet groups, the blood sugar level of ginseng-administered rats is decreased compared with that of control. the oxidation rate of glucose by rat liver slice indicates that only in the carbohydrate deficient diet groups, from the 6th to 15th hour, the oxidation rate of glucose in ginseng-administered group is increased, compared with that of the control. But there is no statistical significance between them. It is thought that Panax Ginseng would effect more on the enzyme system involved in gluconeogenesis and glycogenesis rather than that of carbohydrate oxidation.

• The Korean Journal of Food And Nutrition
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• v.30 no.4
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• pp.830-840
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• 2017

Excessive body weight gain during the growth period of early life may predispose individuals towards obesity and metabolic disorder in later life. We investigated the possibility of using the food efficiency ratio as an early indicator for predicting susceptibility to diet-induced obesity and insulin resistance. Four-week-old, prepubertal, male Sprague Dawley rats were divided into obesity-prone and obesity-resistant groups based on food efficiency ratio values after five days on a high-fat diet. Metabolic parameters measured after 2, 6, and 10 weeks, and specific phenotypes were compared with each group. Obesity-prone rats had higher increases in body weight and fat mass compared to obesity-resistant rats over the study period. Obesity-prone rats became glucose intolerant early in this study and remained so throughout the experimental period, with increases in fat weight and leptin levels occurring first, followed by increases in insulin level. Gluconeogenesis and insulin resistance significantly increased in obesity-prone groups in which activities of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase were increased and glucokinase activity decreased. Higher food efficiency ratio at an early age was closely correlated with body fat accumulation, hyperleptinemia, and hyperinsulinemia of middle and elderly age. We suggest a high food efficiency ratio in prepubertal subjects may be a useful predictor of future obesity and insulin resistance.

• Journal of agriculture & life science
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• v.43 no.4
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• pp.15-20
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• 2009

The transition from pregnancy to lactation, commonly referred to as the "transition period" is characterized by dramatic changes in metabolic processes and their regulation in order to prepare the dairy cow for parturition and lactogenesis. An important adaptation to lactation is the increase in gluconeogenesis by the liver to meet the tremendous increase in demand of glucose for lactose synthesis, and the accumulation of lipid in adipose tissue during pregnancy, its mobilization that begins prior to lactation and the dramatic increase in plasma NEFA concentration early lactation. Epinephrine and insulin, the homeostatic regulators of metabolism are responsible for the adaptations of lipid and carbohydrate metabolism in support of milk production along with mobilization of body fat to meet overall energy demands because dry matter intake is insufficient to meet these demands during early lactation.

• Development and Reproduction
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• v.27 no.2
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• pp.77-89
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• 2023

Metformin is the most widely used anti-diabetic drug that helps maintain normal blood glucose levels primarily by suppressing hepatic gluconeogenesis in type II diabetic patients. We previously found that metformin induces apoptotic death in H4IIE rat hepatocellular carcinoma cells. Despite its anti-diabetic roles, the effect of metformin on hepatic de novo lipogenesis (DNL) remains unclear. We investigated the effect of metformin on hepatic DNL and apoptotic cell death in H4IIE cells. Metformin treatment stimulated glucose consumption, lactate production, intracellular fat accumulation, and the expressions of lipogenic proteins. It also stimulated apoptosis but reduced autophagic responses. These metformin-induced changes were clearly reversed by compound C, an inhibitor of AMP-activated protein kinase (AMPK). Interestingly, metformin massively increased the production of reactive oxygen species (ROS), which was completely blocked by compound C. Metformin also stimulated the phosphorylation of p38 mitogen-activated protein kinase (p38MAPK). Finally, inhibition of p38MAPK mimicked the effects of compound C, and suppressed the metformin-induced fat accumulation and apoptosis. Taken together, metformin stimulates dysregulated glucose metabolism, intracellular fat accumulation, and apoptosis. Our findings suggest that metformin induces excessive glucose-induced DNL, oxidative stress by ROS generation, activation of AMPK and p38MAPK, suppression of autophagy, and ultimately apoptosis.

• Archives of Pharmacal Research
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• v.25 no.6
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• pp.923-931
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• 2002

Sopungsungi-won (SP) is a known for\mula for senile constipation and diabetes mellitus, based on traditional Korean medicine. The preventive effect of SP on the development of overt diabetes in Zucker diabetic fatty (ZDF) rats was evaluated. When administered orally through a diet for 8 weeks, diabetic conditions such as hyperglycemia, polydipsia and hypertriglyceridemia were all ameliorated in SP-treated rats. In parallel with the onset and progression of hyperglycemia in the ZDF control rats; there was a marked decline in plasma insulin concentrations from 26.1 $\mu$U/ml, at age 7 weeks, to 14.8 $\mu$U/ml at age 15 weeks. In the SP-treated rats, however, the plasma insulin concentrations did not decline, and SP at a dose of 5 g/kg significantly increased the insulin levels to 31.9 $\mu$U/ml. Early normalization of plasma insulin and a retained ability to subsequently increase plasma insulin were indicative of a pancreatic $\beta$ cell protective action by the SP for\mula. In addition, expressions of an insulin-responsive gene and corresponding protein, glucose transporter 4 (GLUT4), in skeletal \muscle, were also determined in SP- and rosiglitazone-treated ZDF rats. mRNA and protein levels of GLUT4 in SP-treated rats were upregulated in a dose dependent manner. Furthermore, when ZDF rats were treated with 2 g/kg of the SP for\mula, the activity of glucose-6-phosphatase was decreased by 49%, whereas the activity of glucokinase was increased by 196%, compared to the ZDF control rats. Taken together, these data provide evidence that the SP for\mula markedly lowered the plasma glucose levels, probably through an effect not only on improvement of insulin action, but through a combined sti\mulation of glycolysis and an inhibition of gluconeogenesis in the liver, and also suggest the validity of SP's clinical use in the treatment of type 2 diabetes mellitus following further toxicological investigation.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.506-513
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• 2004

Spirulina produces $\gamma$-linolenic acid (GLA), an important pharmaceutical substance, in a relatively low level compared with fungi and plants, prompting more research to improve its GLA yield. In this study, metabolic flux analysis was applied to determine the cellular metabolic flux distributions in the GLA synthetic pathways of two Spiru/ina strains, wild type BP and a high­GLA producing mutant Z19/2. Simplified pathways involving the GLA synthesis of S. platensis formulated comprise of photosynthesis, gluconeogenesis, the pentose phosphate pathway, the anaplerotic pathway, the tricarboxylic cycle, the GLA synthesis pathway, and the biomass syn­thesis pathway. A stoichiometric model reflecting these pathways contains 17 intermediates and 22 reactions. Three fluxes - the bicarbonate (C-source) uptake rate, the specific growth rate, and the GLA synthesis rate - were measured and the remaining fluxes were calculated using lin­ear optimization. The calculation showed that the flux through the reaction converting acetyl­CoA into malonyl-CoA in the mutant strain was nearly three times higher than that in the wild­type strain. This finding implies that this reaction is rate controlling. This suggestion was sup­ported by experiments, in which the stimulating factors for this reaction $(NADPH\;and\;MgCl_{2})$ were added into the culture medium, resulting in an increased GLA-synthesis rate in the wild type strain.

• Preventive Nutrition and Food Science
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• v.21 no.1
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• pp.62-67
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• 2016

Green tea (Camellia sinensis) is one of the most popular beverages in the world and has been acknowledged for centuries as having significant health benefits. (-)-Epigallocatechin-3-gallate (EGCG) is the most abundant catechin in green tea, and it has been reported to have health benefit effects. Peroxisome proliferator-activated receptor ${\gamma}$ coactivator $(PGC)-1{\alpha}$ is a crucial regulator of mitochondrial biogenesis and hepatic gluconeogenesis. The objective of this study was to investigate whether EGCG from green tea can affect the ability of transcriptional regulation on $PGC-1{\alpha}$ mRNA expression in HepG2 cells and 3T3-L1 adipocytes. To study the molecular mechanism that allows EGCG to control $PGC-1{\alpha}$ expression, the promoter activity levels of $PGC-1{\alpha}$ were examined. The $PGC-1{\alpha}$ mRNA level was measured using quantitative real-time PCR. The -970/+412 bp of $PGC-1{\alpha}$ promoter was subcloned into the pGL3-Basic vector that includes luciferase as a reporter gene. EGCG was found to up-regulate the $PGC-1{\alpha}$ mRNA levels significantly with $10{\mu}mol/L$ of EGCG in HepG2 cells and differentiated 3T3-L1 adipocytes. $PGC-1{\alpha}$ promoter activity was also increased by treatment with $10{\mu}mol/L$ of EGCG in both cells. These results suggest that EGCG may induce $PGC-1{\alpha}$ gene expression, potentially through promoter activation.

• BMB Reports
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• v.49 no.12
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• pp.681-686
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• 2016

Fructose 1,6-bisphosphate aldolase (FBA) is important for both glycolysis and gluconeogenesis in life. Class II (zinc dependent) FBA is an attractive target for the development of antibiotics against protozoa, bacteria, and fungi, and is also widely used to produce various high-value stereoisomers in the chemical and pharmaceutical industry. In this study, the crystal structures of class II Escherichia coli FBA (EcFBA) were determined from four different crystals, with resolutions between $1.8{\AA}$ and $2.0{\AA}$. Native EcFBA structures showed two separate sites of Zn1 (interior position) and Zn2 (active site surface position) for $Zn^{2+}$ ion. Citrate and TRIS bound EcFBA structures showed $Zn^{2+}$ position exclusively at Zn2. Crystallographic snapshots of EcFBA structures with and without ligand binding proposed the rationale of metal shift at the active site, which might be a hidden mechanism to keep the trace metal cofactor $Zn^{2+}$ within EcFBA without losing it.