• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.211-216
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• 2004

Mono-and diacylglycerol-enriched oil was produced from corn oil through enzymatic glycerolysis using 1,3-specific immobilized lipase in solvent-free system and stirred-tank batch reactor. HPLC analysis revealed enriched oil was respectively composed of: 45.05, 16.27, 23.05, and 14.98% triacylglycerol, 1,3-diacylglycerol, 1,2-diacylglycerol, and monoacylglycerol; 13.21, 0.15, 2.02, 34.36, 49.12, and 1.14 mol% palmitic, palmitoleic, stearic, oleic, linoleic, and linolenic acids; and 0.014, 0.029, 0.010 and 0.053% ${\alpha},\;{\gamma},\;{\delta}-$, and total tocopherols. Physiochemical and melting properties of enriched oil were evaluated. Oxidative stability study revealed enriched oil showed higher peroxide and p-anisidine values than corn oil. Rosemary extracts (100 to 300 ppm) reduce oxidation.

• Journal of Nutrition and Health
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• v.31 no.1
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• pp.21-27
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• 1998

The objective of this study was to observe the effect of dietary calcium(Ca) level on colonic mucosal levels of cell proliferation, 1, 2-diacylglycerol(DAG), TXB2, PGE2 and phospholipid fatty acid composition which have been known as biomarkers for colon cancer. One hundred male Sprague Dawley rats, at 7 weeks of age, were divided into two fat type groups. Each group of which was further divided into two Ca level groups. Each rt was intramuscularly injected with 1, 2,-dimenthylhydrazine(DMH) for 6 weeks (total dose of 180mg/kg body weight) and simultaneously fed one of four experimental diets containing 15% dietary fat(corn oil or perilla oil )and 0.3% or 1.0% Ca by weight for 20 weeks. Compared to corn oil, perilla oil significantly reduced cell proliferation by decreasing labeling index, proliferating zone, crypt length in colonic mucosa and colonic mucosa and colonic mucosal levels of DAG, TXB2 . PGE2 and phospolipid (PL) arachidonic acid distribution. The effect of Ca on biomarketrs was different depending on the type of dietary fat comsumed . Ca effect of Ca on biomarkers was different depending on the type of dietary fat comsumed. Ca effect was not significantly shown in the PO group, but it was significant in the CO group in which high Ca(1.0%) decreased the levels of levels of PL-C20 : 4(%), DAG and PGE2 . However , high Ca supplementation had shown only the trends of improving cell proliferation. Overall , high dietary Ca significantly reduced cell proliferation by inhibiting the synthesis of eicosanoid and DAG with reduced distribution of PL-C20 : 4 , which may have resulted in lower activation of PKC through reduced signal transduction. Since a high level of dietary Ca was more effective in reducing the risk factor against colon cancer in corn oil fed rats, it could be suggested that a higher amount of dietary Ca be consumed , especially when more vegetable oil rich in linoleic acid is included in the diet.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.375.4-376
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• 2002

Acyl CoA:diacylglycerol acyltransferase (DGAT) is a key enzyme involved in triacylglycerol synthesis. Too much accumulation of triacylglycerol in certain organs and tissues of the body causes high risk conditions of fatty liver. obesity and hypertriglyceridemia. leading to serious diseases of atherosclerosis. Therefore, DGAT inhibition may be worthwhile strategy for the treatment of triglyceride metabolism disorders. such as obesity or hypertriglyceridemia. (omitted)

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.267.1-267.1
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• 2003

Diacylglycerol acyltransferase (DGAT) is a microsomal enzyme that plays a central role in the metabolism of cellular glycerolipid. Recently, the generation of DGA T-deficient mice has provided a better understanding of triglyceride synthesis and its relationship to obesity. Therefore DGAT is an attractive target for treatments of triglyceride metabolism disorders, such as obesity or hypertriglyceridemia. (omitted)

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.142.1-142
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• 2003

Mono-, diacylglycerol were synthesized by glycerolysis of bran oil and glycerol using IM60 (an immobilized lipase) in a stirred batch reactor for 72 hours. After glycerolysis, the composition TAG, DAG, MAG in product was 41.7%, 44.7%, and 11.1%, respectively. Glycerol was separated, then this mixture product was undergone fractionation for winterization followed. The fractionation was performed using hexane and acetone solvent to reduce palmitic acid at the low temperature for overnight individually. Temperature was set -40$^{\circ}C$, -14$^{\circ}C$, -8$^{\circ}C$ and 0$^{\circ}C$, respectively. By considering results from this experiments, fractionation with hexane at -8$^{\circ}C$ was most efficient regarding to yield without crystallization.

• Korean Journal of Food Science and Technology
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• v.51 no.3
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• pp.272-277
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• 2019

The effects of medium-chain enriched diacylglycerol (MCE-DAG) oil on hepatic cholesterol homeostasis were investigated. HepG2 hepatocytes were treated with either 0.5, 1.0, or $1.5{\mu}g/mL$ of MCE-DAG for 48 h. There was no evidence of cytotoxicity by MCE-DAG up to $1.5{\mu}g/mL$. The level of proteins for cholesterol uptake including CLATHRIN and LDL receptor increased by MCE-DAG in a dose-dependent manner (p<0.05). Furthermore, proprotein convertase subtilisin/kexin type 9, an inhibitor of LDLR, was dose-dependently diminished (p<0.05), indicating cholesterol clearance raised. MCE-DAG significantly increased 3-hydroxy-3-methylglutaryl-coenzyme A reductase and acetyl-CoA acetyltransferase2 (p<0.05), required for cholesterol synthesis, and their transcriptional regulator sterol regulatory element-binding protein2 (p<0.05). These findings suggest that given conditions of prolonged sterol fasting in the current study activated both hepatic cholesterol synthesis and clearance by MCE-DAG. However, total intracellular level of cholesterol was not altered by MCE-DAG. Taken together, MCE-DAG has the potential to prevent hypercholesterolemia by increasing hepatic cholesterol uptake without affecting intracellular cholesterol level.

• Korean Journal of Food Science and Technology
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• v.42 no.2
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• pp.246-249
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• 2010

Diacylglycerol (DAG) was produced from lipase by the catalyzed synthesis of soybean oil (SBO) and glyceryl monooleate (GMO) with Lipozyme TLIM (Thermomyces lanuginosa). Effects of reaction time, molar ratio and enzyme road were studied. When 2:1, 1:1 and 1:2 (SBO:GMO) molar ratios with 20% Lipozyme TLIM were applied in a 1-hr reaction, the concentrations of DAG produced were 17.8, 20.0 and 20.4 g/100 g oil, respectively. Different amounts (2, 5, 10 and 20%) of Lipozyme TLIM were used at a 1:2 (SBO:GMO) molar ratio, and the concentrations of DAG produced in a 1-hr reaction were 10.8, 14.0, 16.9 and 20.4 g/100 g oil, respectively. During a 72-hr reaction, 10.8-22.7 g/100 g oil of DAG were produced under the reaction conditions in this study.

• BMB Reports
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• v.50 no.7
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• pp.367-372
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• 2017

Monoacylglycerol acyltransferase 1 (MGAT) is a microsomal enzyme that catalyzes the synthesis of diacylglycerol (DAG) and triacylglycerol (TAG). However, the subcellular localization and catalytic function domain of this enzyme is poorly understood. In this report, we identified that murine MGAT1 localizes to the endoplasmic reticulum (ER) under normal conditions, whereas MGAT1 co-localize to the lipid droplets (LD) under conditions of enriching fatty acids, contributing to TAG synthesis and LD expansion. For the enzyme activity, both the N-terminal transmembrane domain and catalytic HPHG motif are required. We also show that the transmembrane domain of MGAT1 consists of two hydrophobic regions in the N-terminus, and the consensus sequence FLXLXXXn, a putative neutral lipid-binding domain, exists in the first transmembrane domain. Finally, MGAT1 interacts with DGAT2, which serves to synergistically increase the TAG biosynthesis and LD expansion, leading to enhancement of lipid accumulation in the liver and fat.

• YAKHAK HOEJI
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• v.41 no.6
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• pp.782-788
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• 1997

This study was designed to characterize glucose-enhancing effects on endotoxin-induced prostaglandin production in primary cultured rat vascular smooth muscle cells (VSMC). High glucose treatment significantly augmented prostaglandin (PG) synthesis in lipopolysaccharide (LPS)-stimulated VSMC and this effect was maximal at the concentration of 4mg/ml. It has been reported that increases in glucose metabolism through sorbitol pathway could alter the cytosolic $NADH/NAD^+$ ratio and this change favors de novo synthesis of diacylglycerol (DAG) and, in turn. Results in the activation of protein kinase C (PKC) in vascular tissues. Protein kinase C (PKC) inhibitors, staurosporin and H7, blocked the glucose enhancing effect, and DAG, a PKC activator, significantly increased the PG production stimuated by LPS. Sodium pyruvate, which can reverse the alteration in cytosolic NADH/NAD+ ratio, reduced the high glucose effect on PG production. And also, zopolrestat, a strong aldose reductase inhibitor, almost completely blocked the augmentation effect of glucose on PG synthesis. Arachidonic acid release was significantly increased in high glucose treated group, which implied the increase in $PLA_2$ activity was associated with glucose enhancing effect. Metabloic, labeling study clearly showed that de novo synthesis of prostaglandin H synthase-2 (PGHS-2) is greatly increased in high glucose treated group and this was mitigated by the treatment of zopolrestat. Taken together, the activation of PKC through sorbitol pathway increased the activities of $PLA_2$ and PGHS which resulted in the augmentation in LPS-induced PG production in high glucose treated VSMC.

• Journal of Photoscience
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• v.5 no.1
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• pp.1-10
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• 1998

The susceptibility of chilling-resistant spinach plants. and of chilling-sensitive squash plants to photoinhibition was compared in terms of the activity of photosystem II, in relation to the deuce of fatty acid unsaturation of chloroplast membrane lipids. From thylakoid membranes of the plants. monogalactosyl diacylgtycerol, digalactosyl diacylglycerol. sulfoquinovosyt diacylglycerol, and phosphatidylglycerol were seperated as major lipid classes. It was found that the content of cis-unsaturated fatty acids of phosphatidylglycerol was greater by 32% in spinach than that in squash. When leaf disks were exposed to light at 5$\circ$C, 15$\circ$C and 25$\circ$C, photochemical efficiency of photosystem II. measured as the ratio of the variable to the maximum fluorescence of chlorophyll, declined markedly in squash plants, as compared to spinach plants. When leaf disks were exposed to strong light in the presence of lincomycin, an inhibitor of protein synthesis in chloroplasts, photoinhibition was accelerated in the two types of plants. Moreover, lincomycin treatment abolished the differences in the degree of susceptibility to strong light, which had been observed between the two types of plants. When the extent of photoinhibition of photosystem II-mediated electron transport was compared in thylakoid membranes isolated from the two types of plants, there were no differences in the degree of inactivation of photosystem II activity. However, when intact leaf disks were exposed to strong light either at 10$\circ$C or at 25$\circ$C, and then were allowed to recover either at 17$\circ$C or at 25$\circ$C in dim light. chilling-resistant plants such as spinach and pea showed marked recovery from photoinhibition, in contrast to chilling-sensitive plants, such as squash and sweet potato. whose recovery was strongly dependent on the temperature. These findings are discussed in relation to the unsaturation of fatty acids in membrane phosphatidylglycerol. It appears that fatty acid unsaturation of membrane lipids accelerates the recovery of photosystem H from photoinhibition, without affecting the photo-induced inactivation process of photosystem II associated with photoinhibition.