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1.
Chinese Journal of Biotechnology ; (12): 3481-3493, 2023.
Article in Chinese | WPRIM | ID: wpr-1007971

ABSTRACT

Diacylglycerol (DAG) is an intermediate product in lipid metabolism and plays an important physiological role in human body. It is mainly prepared by hydrolyzing lipid with lipase. However, research on the detection method of 1, 2-diacylglycerol (1, 2-DAG) and 1, 3-diacylglycerol (1, 3-DAG) and catalytic specificity of lipase was not enough, which limits its wide application. To address these challenges, an efficient quantitative detection method was first established for 1, 2-DAG (0.025-0.200 g/L) and 1, 3-DAG (0.025-0.150 g/L) by combining supercritical fluid chromatography with evaporative light scattering detector and optimizing the detection and analysis parameters. Based on the molecular docking between Thermomyces lanuginosus lipase (TLL) and triolein, five potential substrate binding sites were selected for site-specific saturation mutation to construct a mutation library for enzyme activity and position specificity screening. The specificity of sn-1, 3 of the I202V mutant was the highest in the library, which was 11.7% higher than the specificity of the wild type TLL. In summary, the position specificity of TLL was modified based on a semi-rational design, and an efficient separation and detection method of DAG isomers was also established, which provided a reference for the study of the catalytic specificity of lipase.


Subject(s)
Humans , Diglycerides , Molecular Docking Simulation , Binding Sites , Catalysis , Lipase/genetics
2.
São Paulo; s.n; s.n; 2017. 93 p. tab, graf, ilus.
Thesis in Portuguese | LILACS | ID: biblio-875303

ABSTRACT

Mono e diacilgliceróis são produtos empregados na indústria alimentícia, farmacêutica, cosmética e química como emulsificantes e melhoradores de viscosidade de produtos alimentícios, cosméticos e farmacêuticos. No entanto, a forma mais usual de obtê-los é por síntese química, o que acaba rendendo produtos finais caros e com atributos de qualidade, rendimento e de aplicabilidade tecnológica inferiores aos esperados. A busca por formas de obtenção mais racionais, eficientes e com melhor padrão de qualidade destes produtos foi o objetivo principal do trabalho, por meio de hidrólise parcial enzimática, que necessita de condições de reação mais brandas. Foram avaliadas a hidrólise enzimática descontína, empregando como substrato a trioleína técnica, e a hidrólise enzimática descontínua-alimentada, usando como substrato o óleo de girassol médio oléico. Foi utilizada, em ambos processsos, a lipase imobilizada sn-1,3 específica Lipozyme RM IM (de Rhizomucor miehei). A caracterização dos padrões e dos substrados, bem como o acompanhamento da formação dos produtos da hidrólise enzimática foram feitos por determinação da porcentagem de hidrólise, cromatografia em camada delgada (TLC), dos perfis das curvas de fusão e cristalização por calorimetria diferencial de varredura (DSC), cromatografia gasosa (CG) e cromatografia de exclusão de tamanho de alto desempenho (HPSEC). Os parâmetros de hidrólise descontínua foram o tempo de reação, a temperatura e a concentração inicial de substrato. Os parâmetros de hidrólise descontínua-alimentada foram tempo de enchimento e intervalo de alimentação de substrato. Para as respostas analíticas de porcentagem de hidrólise e de composição de frações lipídicas foi aplicado um modelo de regressão múltipla com base em metodologia de superfície de resposta. Os resultados experimentais observados nas reações de hidrólise enzimática descontínua de trioleína técnica mostraram de 24,7 a 34,2% de mono e diacilgliceróis (para 5% de óleo na emulsão) e de 21,4 a 33,6% de mono e diacilgliceróis (para 20% de óleo na emulsão). Os resultados experimentais observados nas reações de hidrólise enzimática descontínua-alimentada de óleo de girassol médio oléico (para 15% de óleo na emulsão), mostraram de 7,9 a 31,8% de mono e diacilgliceróis. Os modelos de superfície de resposta foram considerados significativos e preditivos. As hidrólises obtidas no formato descontínuo e descontínuo-alimentado permitiram efetivamente a obtenção de frações de mono/ diacilgliceróis com vários graus de eficiência de conversão e com corretas identificação e quantificação das frações de lipídios procuradas. As correlações feitas entre porcentagem de hidrólise e entalpias de cristalização e fusão, corroboradas com os resultados qualitativos e/ou quantitativos diretos obtidos na cromatografia de camada delgada (TLC) e de HPSEC, demonstraram que estes atributos podem positivamente indicar a ocorrência efetiva de reação de hidrólise, além de auferir uma escala de desempenho de reação alinhada com o previsto na literatura, à medida que são aumentadas a temperatura, o tempo de hidrólise e a porcentagem inicial de substrato oleoso, sob regime descontínuo, e que puderam ser melhoradas, de forma inovadora, sob parâmetros de tempo total de alimentação e de intervalo de alimentação, sob regime descontínuo-alimentado. A hidrólise parcial enzimática de triacilgliceróis utilizando lipase imobilizada sn-1,3 específica pode ser considerada uma alternativa às vias químicas para a produção de misturas de mono e diacilgliceróis para utilização como aditivos químicos.


Mono and diacylglycerols are products used in the food, pharmaceutical, cosmetic and chemical industries as emulsifiers and viscosity improvers for food products, cosmetics and pharmaceuticals. However, the most usual forms of obtaining them are by chemical synthesis, which ends up yielding expensive final products with attributes of quality, yield and technological applicability lower than expected. The search for more rational, efficient and better quality standards of these products was the aim of the work, through partial enzymatic hydrolysis, which requires milder reaction conditions. Discontinuous enzymatic hydrolysis was evaluated using technical triolein as substrate and discontinuous-fed enzymatic hydrolysis using as the substrate the mid oleic sunflower oil. In both processes, immobilized lipase sn-1,3 specific Lipozyme RM IM (from Rhizomucor miehei) was used. The characterization of the patterns and substrates, as well as the monitoring of the formation of the products from the enzymatic hydrolysis were made by determining the percentage of hydrolysis, thin layer chromatography (TLC), profiles of the melting and crystallization curves by differential scanning calorimetry ( DSC), gas chromatography (GC) and high performance size exclusion chromatography (HPSEC). The parameters of discontinuous hydrolysis were the reaction time, the temperature and the initial substrate concentration. The parameters of discontinuous-fed hydrolysis were filling time and substrate feed interval. For the analytical responses of hydrolysis percentage and composition of lipid fractions a multiple regression model was applied based on response surface methodology. The experimental results observed in the reactions of discontinuous enzymatic hydrolysis of technical triolein indicated amounts of mono- and diacylglycerols from 24.7 to 34.2% (for 5% of oil in the emulsion) and from 21.4 to 33.6% for mono and diacylglycerols with 20% oil in the emulsion. The experimental results observed in the reactions of discontinuous-fed enzymatic hydrolysis of mid oleic sunflower oil (for 15% oil in the emulsion), showed from 7.9 to 31.8% of mono and diacylglycerols. Response surface models were considered significant and viii predictive. The hydrolysis obtained in the discontinuous and discontinuous-fed form allowed to obtain fractions of mono / diacylglycerols with various degrees of conversion efficiency and with correct identification and quantification of the lipid fractions sought. The correlations between the percentage of hydrolysis and enthalpies of crystallization and fusion, corroborated with the qualitative and / or quantitative direct results obtained in thin layer chromatography (TLC) and HPSEC, showed that these attributes can positively indicate the effective occurrence of reaction of Hydrolysis, in addition to achieving a reaction performance scale in line with the literature, as the temperature rate, the hydrolysis time and the initial percentage of oily substrate are increased under a discontinuous regime and can be improved, in a innovative form, under parameters of total filling time and feeding interval, under a fed-batch regime. The partial enzymatic hydrolysis of triacylglycerols using specific sn-1,3-specific immobilized lipase may be considered an alternative to the chemical pathways for the production of mono- and diacylglycerol blends for use as chemical additives.


Subject(s)
Diglycerides/analysis , Hydrolysis , Calorimetry, Differential Scanning , Oils , Chromatography, Thin Layer/methods , Monoglycerides/classification , Lipase
3.
IJPR-Iranian Journal of Pharmaceutical Research. 2015; 14 (1): 243-249
in English | IMEMR | ID: emr-154885

ABSTRACT

Euphorbia macrostegia or Persian wood spurge is one of the seventeen endemic plants of this genus in Iran. Three triterpenoids, 24-methylenecycloartan-3 beta -ol [1], butyrospermol [2] and cycloartenol [3] and three diglycerides, 1,2-di-O- alpha -linolenoyl-sn-glycerol [4], 1-O-linoleoyl-3- O-palmitoyl-sn-glycerol [5] and 1-O- alpha -linolenoyl-2-O-palmitoyl-sn-glycerol [6] were isolated from the hexane soluble part of methanol-dichloromethane extracts of the aerial parts of Euphorbia macrostegia Boiss. The structures of all compounds were elucidated using different spectroscopy methods including, [1]H NMR, [13]C NMR, HSQC, HMBC, EI-MS and IR. The triterpenes and the unsaturated fatty acids moieties of the diglycerides isolated from the plant were reported previously to have analgesic, anticancer, bactericidal and antifungal activity. Here, we show that E. macrostegia is a new source for the above mentioned biologically active compounds


Subject(s)
Phytochemicals , Plant Extracts , Triterpenes , Diglycerides
4.
Yonsei Medical Journal ; : 951-960, 2015.
Article in English | WPRIM | ID: wpr-40869

ABSTRACT

PURPOSE: In epidemiologic and animal studies, a high fat diet (HFD) has been shown to be associated with lower bone mineral density (BMD) and a higher risk of osteoporotic fractures. Meanwhile, consuming a HFD containing diacylglycerol (DAG) instead of triacylglycerol (TAG) is known to offer metabolically beneficial effects of reductions in body weight and abdominal fat. The purpose of this study was to investigate the effects of a HFD containing DAG (HFD-DAG) on bone in mice. MATERIALS AND METHODS: Four-week-old male C57BL/6J mice (n=39) were divided into three weight-matched groups based on diet type: a chow diet group, a HFD containing TAG (HFD-TAG) group, and a HFD-DAG group. After 20 weeks, body composition and bone microstructure were analyzed using dual energy X-ray absorptiometry and micro-computed tomography. Reverse transcription-polymerase chain reaction (PCR) and real-time PCR of bone marrow cells were performed to investigate the expressions of transcription factors for osteogenesis or adipogenesis. RESULTS: The HFD-DAG group exhibited lower body weight, higher BMD, and superior microstructural bone parameters, compared to the HFD-TAG group. The HFD-DAG group showed increased expression of Runx2 and decreased expression of PPARgamma in bone marrow cells, compared to the HFD-TAG group. The HFD-DAG group also had lower levels of plasma glucose, insulin, total cholesterol, and triglyceride than the HFD-TAG group. CONCLUSION: Compared to HFD-TAG, HFD-DAG showed beneficial effects on bone and bone metabolism in C57BL/6J mice.


Subject(s)
Animals , Male , Mice , Absorptiometry, Photon , Adipogenesis , Body Composition , Body Weight , Bone Density/drug effects , Bone Marrow Cells/metabolism , Diet, High-Fat/adverse effects , Dietary Fats/pharmacology , Diglycerides/administration & dosage , Mice, Inbred C57BL , Osteogenesis/drug effects , Real-Time Polymerase Chain Reaction , Triglycerides , X-Ray Microtomography
5.
Journal of Korean Diabetes ; : 65-70, 2014.
Article in Korean | WPRIM | ID: wpr-726903

ABSTRACT

Non-alcoholic fatty liver disease (NAFLD) is emerging as a world-wide health problem and is currently recognized as a hepatic manifestation of metabolic syndrome. It is an umbrella term to describe a wide range of diseases from simple steatosis to non-alcoholic hepatosteatosis (NASH) and NSAH-related liver cirrhosis. NAFLD is mainly associated with insulin resistance which allows increased free fatty acid (FFA) flux to the liver by increasing lipolysis from adipose tissue, triggering macrophage/immune activation, decreasing skeletal muscle glucose uptake, and increasing de novo lipogenesis. Increased FFA pool in the liver, in turn, increases lipotoxic intermediates, such as ceramides, diacylglycerols, and lysophosphatidylcholines, which are responsible for mitochondrial dysfunction and endoplasmic reticulum stress, resulting in inflammation of the liver. When inflammation is severe enough to affect stellate cells, hepatic fibrosis can be induced.


Subject(s)
Adipose Tissue , Ceramides , Diglycerides , Endoplasmic Reticulum Stress , Fatty Liver , Fibrosis , Glucose , Hepatic Stellate Cells , Inflammation , Insulin Resistance , Lipogenesis , Lipolysis , Liver , Liver Cirrhosis , Lysophosphatidylcholines , Muscle, Skeletal , Obesity
6.
DARU-Journal of Faculty of Pharmacy Tehran University of Medical Sciences. 2011; 19 (4): 249-256
in English | IMEMR | ID: emr-114110

ABSTRACT

Olanzapine is an antipsychotic used in treatment of schizophrenia. This research was carried out to design oral controlled release matrix pellets of water insoluble drug Olanzapine [OZ], using blend of Sodium Alginate [SA] and Glyceryl Palmito-Stearate [GPS] as matrix polymers, micro crystalline cellulose [MCC] as spheronizer enhancer and Sodium Lauryl Sulphate [SLS] as pore forming agent. OZ formulations were developed by the pelletization technique by drug loaded pellets and characterized with regard to the drug content, size distribution, Scanning Electron Microscopy [SEM], Differential Scanning Calorimetry [DSC], Fourier Transform Infrared Spectroscopy [FTIR] and X-ray Diffraction study [XRD]. Stability studies were carried out on the optimized formulation for a period of 90 days at 40 +/- 2°C and 75 +/- 5% relative humidity. The drug content was in the range of 93.34-98.12%. The mean particle size of the drug loaded pellets was in the range 1024 to 1087 micro m. SEM photographs and calculated sphericity factor confirmed that the prepared formulations were spherical in nature. The compatibility between drug and polymers in the drug loaded pellets was confirmed by DSC and FTIR studies. Stability studies indicated that pellets are stable. XRD patterns revealed the crystalline nature of the pure OZ. Loose surface crystal study indicated that crystalline OZ is present in all formulations and more clear in formulation F5. Drug release was controlled for more than 24 hrs and mechanism of the drug release followed by Fickian diffusion. It may be concluded that F5 is an ideal formulation for once a day administration


Subject(s)
Drug Implants , Delayed-Action Preparations , Chemistry, Pharmaceutical , Alginates , Hexuronic Acids , Glucuronic Acid , Diglycerides , Polymers , Cellulose , Sodium Dodecyl Sulfate , Microscopy, Electron, Scanning , Calorimetry, Differential Scanning , Spectroscopy, Fourier Transform Infrared , X-Ray Diffraction
8.
IJB-Iranian Journal of Biotechnology. 2009; 7 (2): 67-74
in English | IMEMR | ID: emr-91145

ABSTRACT

Lipase from Candida antarctica, fixed on macroporous acrylic resin, has been used for the intermediate production of mono- and diolein by hydrolysis of triolein. The effect of altering concentrations of triolein and glycerol and the function of the molecular sieve on the hydrolysis reaction of triolein were investigated. The highest hydrolysis yield was observed for the utmost concentration of triolein, which gave a hydrolysis optimum at the lower reaction time. Raising the concentration of triolein resulted in a 13.7 times increase in mono-and diolein during reaction period. Addition of glycerol to the reaction mixture had a considerably higher positive effect on the production of monolein than that of diolein. The use of a molecular sieve in the mixture was found to be the most effective environment tested, which demonstrated high activity and excellent selectivity toward the formation of intermediate monolein


Subject(s)
Diglycerides , Glycerides , Lipase , Glycerol , Hydrolysis , Triolein , Chromatography, High Pressure Liquid
9.
Journal of Veterinary Science ; : 189-195, 2009.
Article in English | WPRIM | ID: wpr-151427

ABSTRACT

This study was to investigate the anti-obesity effects of diglyceride (DG)-conjugated linoleic acid (CLA) containing 22% CLA as fatty acids in C57BL/6J ob/ob male mice. There were four experimental groups including vehicle control, DG, CLA, and DG-CLA. The test solutions of 750 mg/kg dose were orally administered to the mice everyday for 5 weeks. CLA treatments significantly decreased mean body weight in the obese mice throughout the experimental period compared to the control (p < 0.01). All test solutions significantly decreased the levels of triglyceride, glucose and free fatty acids in the serum compared with control (p < 0.05). The levels of total cholesterol were also significantly reduced in DG and DG-CLA groups compared with the control group (p < 0.05). CLA significantly decreased weights of renal and epididymal fats compared with the control (p < 0.05). DG and DG-CLA also significantly decreased the epididymal fat weights compared with the control (p < 0.05). A remarkable decrease in the number of lipid droplets and fat globules was observed in the livers of mice treated with DG, CLA, and DG-CLA compared to control. Treatments of DG and CLA actually increased the expression of peroxisome proliferator-activated receptor gamma. These results suggest that DG-CLA containing 22% CLA have a respectable anti-obesity effect by controlling serum lipids and fat metabolism.


Subject(s)
Animals , Male , Mice , Adipose Tissue/drug effects , Anti-Obesity Agents/pharmacology , Blood Chemical Analysis , Body Weight/drug effects , Diglycerides/pharmacology , Disease Models, Animal , Eating/drug effects , Gene Expression Regulation/drug effects , Linoleic Acids, Conjugated/pharmacology , Lipids/blood , Liver/drug effects , Mice, Inbred C57BL , Mice, Obese , Obesity/metabolism , PPAR gamma/metabolism , Time Factors
10.
Arq. bras. endocrinol. metab ; 52(7): 1145-1155, out. 2008. ilus, tab
Article in Portuguese | LILACS | ID: lil-499725

ABSTRACT

OBJETIVO: Avaliar o efeito do consumo crônico de di e trieptanoínas sobre a esteatose hepática (EH) em ratos. METODOLOGIA: Ratos Wistar submetidos à dieta AIN-93 com 0 por cento, 30 por cento ou 50 por cento de substituição do óleo por óleo rico em di e trieptanoína, grupos TAGC(7)0, TAGC(7)30 e TAGC(7)50, respectivamente, por nove meses. O grupo-controle recebeu ração Labina®. Analisaram-se histologia e provas de função e lesão hepática, glicemia e perfil lipídico sérico. Realizaram-se análise de variância, teste F, teste de Dunnet e análises de regressão uni e multivariadas (p < 0,05). RESULTADOS: TAGC(7)0, TAGC(7)30 e TAGC(7)50 desenvolveram EH; 80 por cento de casos graves no TAGC(7)0 contra 40 por cento no TAGC(7)50. Os pesos absoluto (PAF) e relativo do fígado (PRF) foram maiores em TAGC(7)0 e TAGC(7)30 e a glicemia foi maior em TAGC(7)30 e TAGC(7)50, que no grupo-controle. Colesterol total, LDL-c, LDL-c/HDL-c e proteínas totais foram maiores no grupo-controle. O óleo experimental reduziu o PRF e determinou tendência de redução do peso corporal, PAF, percentual de lipídios hepáticos e graus de EH (GHE). As variáveis explicativas para GHE foram peso final, glicemia, albumina, HDL-c, LDL-c, LDL-c/HDL-c, VLDL-c e fosfatase alcalina. CONCLUSÕES: Sugere-se que di e trieptanoínas exerçam efeito hepatoprotetor contra a EH, em ratos, em uma feição dose-dependente.


OBJECTIVE: to evaluate the effect of chronic consumption of di- and triheptanoin on hepatic steatosis (HS) in rats. METHODOLOGY: Wistar rats were submitted to a diet AIN-93 with 0, 30 or 50 percent of its oil substituted with an oil rich in di- and triheptanoin, groups TAGC(7)0, TAGC(7)30 and TAGC(7)50 respectively, for nine months. The control group received Labina®. Liver histology, hepatic lesion and function proofs, glycemia and lipid profile, were performed. Variance analyses, F-test, Dunnet´s test and uni- and multivariate regression analyses were performed (p<0.05). RESULTS: TAGC(7)0, TAGC(7)30 and TAGC(7)50 developed HS; 80 percent of severe cases in TAGC(7)0, as against 40 percent in TAGC(7)50. The absolute (ALW) and relative (RLW) liver weights were higher in TAGC(7)0 and TAGC(7)30, and glycemia was greater in TAGC(7)30 and TAGC(7)50, than in the Control. Total cholesterol, LDL-c, LDL-c/HDL-c and total proteins were higher in the Control. The experimental oil reduced RLW and showed a tendency in the reduction of body weight, ALW, percentage of hepatic lipids and the severity of HS. The explanatory variables in relation to HS were final weight, glycemia, albumin, HDL-c, LDL-c, LDL-c/HDL-c, VLDL-c and alkaline phosphatase. CONCLUSIONS: It is suggested that di- and triheptanoin have a hepatoprotector effect against HS, in rats, in a dose-dependant manner.


Subject(s)
Animals , Male , Rats , Cholesterol/blood , Diglycerides/administration & dosage , Fatty Liver/prevention & control , Triglycerides/administration & dosage , Analysis of Variance , Blood Glucose/analysis , Fatty Liver/pathology , Kidney/pathology , Lipids/blood , Rats, Wistar , Regression Analysis , Triglycerides/biosynthesis
11.
China Journal of Chinese Materia Medica ; (24): 813-815, 2007.
Article in Chinese | WPRIM | ID: wpr-283380

ABSTRACT

<p><b>OBJECTIVE</b>To establish a HPLC method for a new compound 1,3-O-dicaffeoylglycerides determination.</p><p><b>METHOD</b>The separation was performed in a Kromasil C18 column (4.6 mm x 150 mm, 5 microm) with a mobile phase of 0.1% H3PO4: Acetontrile = 75 : 25 (v/v). The flow rate was 1.0 ml x min(-)1 and the temperature of column was 30 degrees C.</p><p><b>RESULT</b>A satisfactory separation between 1, 3-O-dicaffeoylglycerides and impurity was obtained. The calibration curve was linear over the concentration range from 0.051 6 microg to 0.516 microg, r = 0.999 9. The average recoveries was 97.1% (RSD 1.3%). The content of 1,3-O-dicaffeoylglycerides in pineapple leaves from three different batches were 0.033%, 0.034% and 0.031% respectively.</p><p><b>CONCLUSION</b>The method has good selectivity, high recovery and reproducibility, and can be used for the analysis of 1,3-O-dicaffeoylglycerides in pineapple leaves and their quality control.</p>


Subject(s)
Ananas , Chemistry , Caffeic Acids , Chemistry , Chromatography, High Pressure Liquid , Methods , Diglycerides , Chemistry , Molecular Structure , Plant Leaves , Chemistry , Reproducibility of Results
12.
Chinese Journal of Biotechnology ; (12): 425-429, 2005.
Article in Chinese | WPRIM | ID: wpr-305257

ABSTRACT

Diacylglycerol, DAG, because of its multifunctional and nutritional properties, attracted considerable attention recently. Enzymatic synthesis of diacylglycerols from linoleic acid was investigated in a solvent-free reaction in a continuously operated fixed bed reactors containing Lipozyme RM IM. By appropriate manipulation of the fluid-residence time, the relative proportions of the various acylglycerols in the effluent stream can be controlled. In addition, the presence of excess glycerol is effective for the removal of water produced during the esterification reactions. Under the conditions of molar ratio of linoleic acid to glycerol of 0.5, the immoblized enzyme maintained high stability and allowed the reaction to continue for 10 days without significant deterioration in enzyme activity. It was determined that the conversion of fatty acid, content of 1,3-DAG and volume efficiency of reactor reached optima under the conditions: a packaged-bed reactor(with a ratio of packed length to inner diameter of 7.8), reacting temperature at 65 degrees C, molar ratio of linoleic acid to glycerol of 0.5, and feeding flow rate of 1.2 mL/min.


Subject(s)
Catalysis , Diglycerides , Enzyme Stability , Enzymes, Immobilized , Chemistry , Lipase , Chemistry
13.
Benha Medical Journal. 2004; 21 (1): 113-120
in English | IMEMR | ID: emr-172731

ABSTRACT

In platelets, the major stimulatory second messengers are inositol 1, 4, 5 triphosphate [IP3] and 1,2-diacyiglycerol [DAG] produced upon the hydrolysis of phosphoinositides by phosphoinositide-speciftc phospholpase C [P1-PLC]. Pyridoxal-5-phosphate [PLP] is well known as a potent inhibitor of platelet aggregation. The mechanism[s] of its inhibitory action remains to be elucidated. P1-PLC was assayed and the effect of PLP on the assay was examined in an attempt to explain the nature of the inhibitory effect of PLP on platelet function. The assay was satisfactory and was inhibited by PLP with full inhibition at 10mMPLP


Subject(s)
Pyridoxal Phosphate/chemistry , Inositol 1,4,5-Trisphosphate/chemistry , Diglycerides/chemistry , Platelet Aggregation/drug effects
14.
Experimental & Molecular Medicine ; : 201-210, 2002.
Article in English | WPRIM | ID: wpr-198792

ABSTRACT

A20 murine lymphoma cells undergoing Fas-mediated apoptosis showed increase in the activity of phospholipase D (PLD), which is involved in proliferative or mitogenic cellular responses. Using A20 cell lines that were resistant to Fas-induced apoptosis, we investigated the differential effects of Fas cross-linking on PLD activity and sphingolipid metabolism. The basal PLD activities in all of the selected three Fas-resistant clones (#5, #8, and #11) were about 2~4 folds higher than that of wild type A20 cells. Among the PLD isoforms, PLD2 expression was increased in all of the selected Fas-resistant clones. The Fas downstream signaling events triggered by Fas cross-linking, including the activations of PLD, phosphatidy-lcholine-specific phospholipase C (PC-PLC), sphingomyelinase (SMase), the increase in diacylglycerol (DAG) and protein phosphorylation levels, and the translocation of protein kinase C to membrane were not changed in both of Fas-resistant clone #5 and #8. In contrast, Fas cross-linking stimulated the activity of PLD, PC-PLC, and SMase, translocation of PKC, and protein phosphorylation in Fas-resistant clone #11, similar to that of wild type cells. We also found that clone #11 had a different Fas sequence encoding Fas B which has been known to inhibit Fas-induced apoptosis. These findings suggest that increased PLD2 expression resulting in increased basal PLD activity and the blockade of Fas downstream signaling cascades may be involved to limit apoptosis induced by Fas cross-linking.


Subject(s)
Animals , Mice , Antibodies, Monoclonal/immunology , fas Receptor/immunology , Base Sequence , Carrier Proteins/metabolism , Clone Cells , Cross-Linking Reagents/pharmacology , Diglycerides/metabolism , Enzyme Activation/drug effects , Lipids/metabolism , Molecular Sequence Data , Phospholipase D/metabolism , Phosphorylation/drug effects , Protein Kinase C/metabolism , Signal Transduction/drug effects , Sphingomyelin Phosphodiesterase/metabolism , Tumor Cells, Cultured
15.
Biol. Res ; 35(2): 223-229, 2002. ilus
Article in English | LILACS | ID: lil-323345

ABSTRACT

Apoptosis is a means by which organisms dispose of unwanted cells without inducing an inflammatory response. Alterations in apoptosis is a common process by which cells become cancerous. Paradoxically, many cancer chemotherapeutics preferentially kill cancer cells by inducing apoptosis. Diacylglycerol is a lipid second messenger that regulates cell growth and apoptosis and is produced during signal transduction by hydrolysis of membrane phospholipids. Protein kinase Cs are a family of diacyglycerol responsive enzymes that are recruited to cellular membranes as a consequence of diacylglycerol production where they phosphorylate specific target proteins responsible for regulating cell growth. In this review, we will first summarize our current understanding of the role of specific proteins kinase C isoforms in the induction of cell growth/apoptosis. Subsequently, we will discuss how insights gained in lipid-mediated regulation of protein kinase Cs promotes our understanding of the role specific family members play in regulating cell growth. Finally, other diacylglycerol binding proteins involved in regulating apoptosis will be discussed


Subject(s)
Humans , Animals , Antibodies, Antiphospholipid , Apoptosis , Diglycerides , Phospholipids , Protein Kinase C , Carrier Proteins , Cell Division , Diglycerides , Farnesol , Protein Isoforms , Protein Kinase C , Second Messenger Systems , Signal Transduction
18.
Indian J Exp Biol ; 1999 Nov; 37(11): 1075-9
Article in English | IMSEAR | ID: sea-56604

ABSTRACT

The involvement of the signal transduction pathway in mouse liver following whole body irradition was investigated. Mice were exposed to 60Co gamma rays (3 Gy) and sacrificed after different time intervals. Various elements of phosphatidyl inositol signal transduction pathway were investigated. Alterations could be seen as early as 15 min of irradiation. These changes are reflected in elevation in DAG levels and increased activation of PKC, an enzyme which is involved in tumorigenesis. The chronological appearance of various transducers following whole body irradiation is of significance since these early effects may set the stage for radiation-induced tumorigenesis and hence may be used to manipulate tumor response to radiotherapy.


Subject(s)
Animals , Diglycerides/metabolism , Gamma Rays/adverse effects , Liver/metabolism , Male , Mice , Phosphatidylinositols/metabolism , Protein Kinase C/metabolism , Signal Transduction/radiation effects , Whole-Body Irradiation/adverse effects
19.
Indian J Biochem Biophys ; 1997 Dec; 34(6): 479-82
Article in English | IMSEAR | ID: sea-28843

ABSTRACT

Phosphorylation of endogenous phosphatidylinositol was transiently increased following partial hepatectomy but was suppressed during peak DNA synthesis. Formation of inositol trisphosphate was decreased while generation of diacylglycerol and its breakdown to phosphatidic acid was increased. In response to partial hepatectomy protein kinase C was activated due to translocation from cytosol to particulate fraction, but the membrane bound activity was decreased during regeneration. Alteration of certain parameters in the signal transduction pathway apparently facilitates cell proliferation.


Subject(s)
Animals , Diglycerides/metabolism , Hepatectomy , Liver/metabolism , Liver Regeneration/physiology , Male , Phosphatidylinositols/metabolism , Protein Kinase C/metabolism , Rats , Rats, Wistar , Signal Transduction
20.
Iraqi Journal of Pharmaceutical Sciences. 1997; 8: 45-53
in English | IMEMR | ID: emr-44830

ABSTRACT

The major glycolipid component from saccharopolyspora hirsute [N626] was isolated and investigated. Acid hydrolysis of the isolated lipid yielded, glucose, galactose, glycerol and a mixture of fatty acids. Analysis of the latter by gaschromatography showed that they consisted largely of palmitic, stearic and oleic acids


Subject(s)
Saccharopolyspora/chemistry , Diglycerides , Galactose , Glucose
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