Diacylglycerol Content Research Articles

Lipid droplet remodelling and reduced muscle ceramides following sprint interval and moderate-intensity continuous exercise training in obese males.

In obesity, improved muscle insulin sensitivity following exercise training has been linked to the lowering of diacylglycerol (DAG) and ceramide concentrations. Little is known, however, about how improved insulin action with exercise training in obese individuals relates to lipid droplet (LD) adaptations in skeletal muscle. In this study we investigated the hypothesis that short-term sprint interval training (SIT) and moderate-intensity continuous training (MICT) in obese individuals would increase perilipin (PLIN) expression, increase the proportion of LDs in contact with mitochondria and reduce muscle concentrations of DAGs and ceramides. Sixteen sedentary obese males performed 4 weeks of either SIT (4-7 × 30 s sprints at 200% Wmax, 3 days week) or MICT (40-60 min cycling at ~65% VO2peak, 5 days per week), and muscle biopsies were obtained pre- and post-training. Training increased PLIN2 (SIT 90%, MICT 68%) and PLIN5 (SIT 47%, MICT 34%) expression in type I fibres only, and increased PLIN3 expression in both type I (SIT 63%, MICT 67%) and type II fibres (SIT 70%, MICT 160%) (all P<0.05). Training did not change LD content but increased the proportion of LD in contact with mitochondria (SIT 12%, MICT 21%, P<0.01). Ceramides were reduced following training (SIT -10%, MICT -7%, P<0.05), but DAG was unchanged. No training × group interactions were observed for any variables. These results confirm the hypothesis that SIT and MICT results in remodelling of LDs and lowers ceramide concentrations in skeletal muscle of sedentary obese males.

A lumped model of the lipase catalyzed hydrolysis of sardine oil to maximize polyunsaturated fatty acids content in acylglycerols

The aim of this work was to produce diacylglycerols (DAG) and monoacylglycerols (MAG) with a high content of polyunsaturated fatty acids (PUFA). Rhizomucor miehei lipase mediated-hydrolysis of sardine oil was conducted at several water activities. The system was mechanistically modeled to predict the time evolution of the concentration of triacylglycerols, DAG, MAG and free fatty acids (FFA) and the concentration of saturated, mono- and polyunsaturated fatty acids. The release of the first fatty acid from the triacylglycerol was independent on the unsaturation degree. Contrary, the hydrolysis of the second one was highly affected by the degree of unsaturation, PUFA being the fatty acids that showed the highest resistance to hydrolysis. MAG percentage was maximum (7mol%) at lower water activities, while DAG content was favored at higher water activities (35mol%), achieving a 2-fold concentration of DHA.

Hepatic Diacylglycerol-Associated Protein Kinase Cε Translocation Links Hepatic Steatosis to Hepatic Insulin Resistance in Humans

SummaryHepatic lipid accumulation has been implicated in the development of insulin resistance, but translational evidence in humans is limited. We investigated the relationship between liver fat and tissue-specific insulin sensitivity in 133 obese subjects. Although the presence of hepatic steatosis in obese subjects was associated with hepatic, adipose tissue, and peripheral insulin resistance, we found that intrahepatic triglycerides were not strictly sufficient or essential for hepatic insulin resistance. Thus, to examine the molecular mechanisms that link hepatic steatosis to hepatic insulin resistance, we comprehensively analyzed liver biopsies from a subset of 29 subjects. Here, hepatic cytosolic diacylglycerol content, but not hepatic ceramide content, was increased in subjects with hepatic insulin resistance. Moreover, cytosolic diacylglycerols were strongly associated with hepatic PKCε activation, as reflected by PKCε translocation to the plasma membrane. These results demonstrate the relevance of hepatic diacylglycerol-induced PKCε activation in the pathogenesis of NAFLD-associated hepatic insulin resistance in humans.

Effect of metformin on bioactive lipid metabolism in insulin-resistant muscle.

Intramuscular accumulation of bioactive lipids leads to insulin resistance and type 2 diabetes (T2D). There is lack of consensus concerning which of the lipid mediators has the greatest impact on muscle insulin action in vivo Our aim was to elucidate the effects of high-fat diet (HFD) and metformin (Met) on skeletal muscle bioactive lipid accumulation and insulin resistance (IR) in rats. We employed a [U-13C]palmitate isotope tracer and mass spectrometry to measure the content and fractional synthesis rate (FSR) of intramuscular long-chain acyl-CoA (LCACoA), diacylglycerols (DAG) and ceramide (Cer). Eight weeks of HFD-induced intramuscular accumulation of LCACoA, DAG and Cer accompanied by both systemic and skeletal muscle IR. Metformin treatment improved insulin sensitivity at both systemic and muscular level by the augmentation of Akt/PKB and AS160 phosphorylation and decreased the content of DAG and Cer and their respective FSR. Principal component analysis (PCA) of lipid variables revealed that altered skeletal muscle IR was associated with lipid species containing 18-carbon acyl-chain, especially with C18:0-Cer, C18:1-Cer, 18:0/18:2-DAG and 18:2/18:2-DAG, but not palmitate-derived lipids. It is concluded that the insulin-sensitizing action of metformin in skeletal muscle is associated with decreased 18-carbon acyl-chain-derived bioactive lipids.

Effects of frying oils’ fatty acids profile on the formation of polar lipids components and their retention in French fries over deep-frying process

The effects of frying oils’ fatty acids profile on the formation of polar components and their retention in French fries and corresponding deep-fried oils were investigated in the present study, using oils with different fatty acids composition. Our analysis showed that the total polar compounds (TPCs) content in French fries was only slightly lower than that in deep-fried oils, indicating that there was no significant difference considering the amounts of TPCs in French fries and deep-fried oils. Our further analysis showed that different polar components in TPCs distributed differently in deep-fried oils and oils extracted from French fries. Specifically, the level of oligomeric and dimeric triacylglycerols was higher in French fries while oxidized triacylglycerols and diacylglycerols content was higher in deep-fried oils. The different retention of TPCs components in French fries may be explained by their interactions with carbohydrates, which are shown to enhance with the increase of hydrophobic property. Chemometric analysis showed that no correlation between the polar compounds level and saturated fatty acids profile was observed. Meanwhile, the polar compounds content was highly correlated with the formation of trans-C18:1, and a highly positive association between polar compounds and C18:2 content was also observed in palm oil.

Mitochondrial-Targeted Catalase Protects Against High-Fat Diet-Induced Muscle Insulin Resistance by Decreasing Intramuscular Lipid Accumulation.

We explored the role of reactive oxygen species (ROS) in the pathogenesis of muscle insulin resistance. We assessed insulin action in vivo with a hyperinsulinemic-euglycemic clamp in mice expressing a mitochondrial-targeted catalase (MCAT) that were fed regular chow (RC) or a high-fat diet (HFD) or underwent an acute infusion of a lipid emulsion. RC-fed MCAT mice were similar to littermate wild-type (WT) mice. However, HFD-fed MCAT mice were protected from diet-induced insulin resistance. In contrast, an acute lipid infusion caused muscle insulin resistance in both MCAT and WT mice. ROS production was decreased in both HFD-fed and lipid-infused MCAT mice and cannot explain the divergent response in insulin action. MCAT mice had subtly increased energy expenditure and muscle fat oxidation with decreased intramuscular diacylglycerol (DAG) accumulation, protein kinase C-θ (PKCθ) activation, and impaired insulin signaling with HFD. In contrast, the insulin resistance with the acute lipid infusion was associated with increased muscle DAG content in both WT and MCAT mice. These studies suggest that altering muscle mitochondrial ROS production does not directly alter the development of lipid-induced insulin resistance. However, the altered energy balance in HFD-fed MCAT mice protected them from DAG accumulation, PKCθ activation, and impaired muscle insulin signaling.

Correlations Between Cloud Point and Compositional Properties of Palm Oil and Liquid Fractions from Dry Fractionation

AbstractDry fractionation of palm oil can be conducted as a multi‐step process; this gives rise to new softer and harder fractions having multitudes of applications in fat foods. This work focuses on the liquid fractions obtained following a triple‐step fractionation; the cloud point was measured on a set of 125 palm oil, olein, super olein and top olein samples, with the intention to correlate this value to the compositional properties. The Mettler cloud point, the diacylglycerol content, some selected single or groups of triacylglycerols and the iodine value (in total, 11 variables per sample) were measured and entered in a statistical model. A principal component analysis (PCA) was first carried out from which different sub‐groups were highlighted. In each sub‐group, various regressions (simple linear, simple non‐linear and multiple linear) were applied and 28 significant equations were derived. Out of these, one multiple linear regression involving the iodine value, the UUU and PPP contents showed the best correlation with the Mettler cloud point. This equation was selected to predict the cloud point since it was further successfully validated by using a set of 25 other independent samples. A partial least square (PLS) regression was tested and also considered adequate to predict the cloud point.

Drosophila development, physiology, behavior, and lifespan are influenced by altered dietary composition

ABSTRACTDiet profoundly influences the behavior of animals across many phyla. Despite this, most laboratories using model organisms, such as Drosophila, use multiple, different, commercial or custom-made media for rearing their animals. In addition to measuring growth, fecundity and longevity, we used several behavioral and physiological assays to determine if and how altering food media influence wild-type (Canton S) Drosophila melanogaster, at larval, pupal, and adult stages. Comparing 2 commonly used commercial food media we observed several key developmental and morphological differences. Third-instar larvae and pupae developmental timing, body weight and size, and even lifespan significantly differed between the 2 diets, and some of these differences persisted into adulthood. Diet was also found to produce significantly different thermal preference, locomotory capacity for geotaxis, feeding rates, and lower muscle response to hormonal stimulation. There were no differences, however, in adult thermal preferences, in the number or viability of eggs laid, or in olfactory learning and memory between the diets. We characterized the composition of the 2 diets and found particularly significant differences in cholesterol and (phospho)lipids between them. Notably, diacylglycerol (DAG) concentrations vary substantially between the 2 diets, and may contribute to key phenotypic differences, including lifespan. Overall, the data confirm that 2 different diets can profoundly influence the behavior, physiology, morphology and development of wild-type Drosophila, with greater behavioral and physiologic differences occurring during the larval stages.

A controlled‐release mitochondrial protonophore reverses hypertriglyceridemia, nonalcoholic steatohepatitis, and diabetes in lipodystrophic mice

Lipodystrophy is a rare disorder characterized by complete or partial loss of adipose tissue. Patients with lipodystrophy exhibit hypertriglyceridemia, severe insulin resistance, type 2 diabetes, and nonalcoholic steatohepatitis (NASH). Efforts to ameliorate NASH in lipodystrophies with pharmacologic agents have met with limited success. We examined whether a controlled-release mitochondrial protonophore (CRMP) that produces mild liver-targeted mitochondrial uncoupling could decrease hypertriglyceridemia and reverse NASH and diabetes in a mouse model (fatless AZIP/F-1 mice) of severe lipodystrophy and diabetes. After 4 wk of oral CRMP (2 mg/kg body weight per day) or vehicle treatment, mice underwent hyperinsulinemic-euglycemic clamps combined with radiolabeled glucose to assess liver and muscle insulin responsiveness and tissue lipid measurements. CRMP treatment reversed hypertriglyceridemia and insulin resistance in liver and skeletal muscle. Reversal of insulin resistance could be attributed to reductions in diacylglycerol content and reduced PKC-ε and PKC-θ activity in liver and muscle respectively. CRMP treatment also reversed NASH as reflected by reductions in plasma aspartate aminotransferase and alanine aminotransferase concentrations; hepatic steatosis; and hepatic expression of IL-1α, -β, -2, -4, -6, -10, -12, CD69, and caspase 3 and attenuated activation of the IRE-1α branch of the unfolded protein response. Taken together, these results provide proof of concept for the development of liver-targeted mitochondrial uncoupling agents as a potential novel therapy for lipodystrophy-associated hypertriglyceridemia, NASH and diabetes.-Abulizi, A., Perry, R. J., Camporez, J. P. G., Jurczak, M. J., Petersen, K. F., Aspichueta, P., Shulman, G. I. A controlled-release mitochondrial protonophore reverses hypertriglyceridemia, nonalcoholic steatohepatitis, and diabetes in lipodystrophic mice.

Carbon competition between fatty acids and starch during benzoin seeds maturation slows oil accumulation speed

The carbon flow balance is shifted to starch rather than oil accumulation during benzoin seed development stage (80–120 DAF) and thereby lipid deposition speed slows down. Benzoin [Styrax tonkinensis (Pierre) Craib ex Hartwich] is a woody oilseed species with potential value as a biofuel feedstock. However, the continuous drop in seed crude fat concentration during maturation had remained unexplained until it was investigated in this study. Seed filling began 60 days after flowering (DAF), when the hexose-to-sucrose ratio dropped, correlating with substantial morphological changes in kernels. Oil accumulated 20 days earlier than starch, as the concentrations of free fatty acid (50–70 DAF) and diacylglycerols (50–80 DAF) increased rapidly. Fatty acid synthesis slowed between 80 and 120 days, correlating with a sharp increase in the speed of starch deposition, while triacylglycerol accumulation and the profile of fatty acids remained stable. Phosphoglucose isomerase (PGI), pyruvate dehydrogenase complex (PDHC), and malate dehydrogenase (MDH) activities dropped progressively together with acetyl coenzyme carboxylase (ACCase) after 70 DAF before the reserve storage priority shifted from fatty acids to starch. PGI, PDHC, MDH, ACCase, and diglyceride acyltransferase (DAGT) activities rose again at 120 DAF, after which the speed of fatty acid accumulation increased, correlating with a 10-day lag phase in starch accumulation. High glucose 6-phosphate dehydrogenase (G6PDH) activity was observed during oil deposition. Soluble protein continued accumulating as protease activity decreased during benzoin seed development, while the total amylase activity rose twice between 30 and 70 DAF before the ADP-glucose pyrophosphorylase activity and starch content soared high simultaneously after 70 DAF. The collective results suggest that carbon partitioning between starch and lipid accumulation occurs during benzoin kernel development and is responsible for a reduction in the rate at which total fatty acids accumulate between 80 and 120 DAF.

Novel Lipidomic Biomarkers in Hyperlipidemia and Cardiovascular Diseases: An Integrative Biology Analysis.

Lipidomics is a new frontier of omics research and offers much promise for new-generation biomarkers for common complex phenotypes such as hyperlipidemia (HL) and cardiovascular diseases (CVDs). HL is a disorder characterized by increased levels of blood lipids and is a well-established risk factor for CVD. Traditional clinical markers for prognosis of hyperlipidemic individuals are inadequate to forecast or diagnose cardiac events. In this expert review, lipidomic profiles from recent HL and CVD studies were compared with the normolipidemic profile prepared from the Standard Reference Material. Our analysis showed that palmitoyl-lysophosphatidylcholine [LPC(16:0)], the most abundant LPC species in normolipidemic plasma, decreases in HL causative conditions such as high-fat diet, obesity, and diabetes. This is accompanied by increase in free fatty acids (FFAs) and ceramides (Cers). HL was also found to be characterized by increase in small-chain, saturated fatty acid content of diacylglycerols, triacylglycerols, and phosphatidylcholines (PCs). These factors were also associated with increased CVD risk. The decrease in LPC(16:0) in HL and CVD is consistent with its role in regulation of peroxisome proliferator-activated receptor alpha, an approved HL drug target that impacts the uptake and oxidation of fatty acids. FFAs are involved in endothelial-dependent nitric oxide production and activation of nuclear factor κB signaling. Cers control uptake and anabolic catabolism of nutrients in tissues. However, additional studies are required to establish the range of normal and disease levels of the identified lipids in different populations and conditions. In all, these observations underscore that lipidomics deserves greater research attention from the biomarker and precision medicine research communities.

In Vivo Imaging of Diacylglycerol at the Cytoplasmic Leaflet of Plant Membranes.

Diacylglycerol (DAG) is an important intermediate in lipid biosynthesis and plays key roles in cell signaling, either as a second messenger itself or as a precursor of phosphatidic acid. Methods to identify distinct DAG pools have proven difficult because biochemical fractionation affects the pools, and concentrations are limiting. Here, we validate the use of a genetically encoded DAG biosensor in living plant cells. The sensor is composed of a fusion between yellow fluorescent protein and the C1a domain of protein kinase C (YFP-C1aPKC) that specifically binds DAG, and was stably expressed in suspension-cultured tobacco BY-2 cells and whole Arabidopsis thaliana plants. Confocal imaging revealed that the majority of the YFP-C1aPKC fluorescence did not locate to membranes but was present in the cytosol and nucleus. Treatment with short-chain DAG or PMA (phorbol-12-myristate-13-acetate), a phorbol ester that binds the C1a domain of PKC, caused the recruitment of the biosensor to the plasma membrane. These results indicate that the biosensor works and that the basal DAG concentration in the cytoplasmic leaflet of membranes (i.e. accessible to the biosensor) is in general too low, and confirms that the known pools in plastids, the endoplasmic reticulum and mitochondria are located at the luminal face of these compartments (i.e. inaccessible to the biosensor). Nevertheless, detailed further analysis of different cells and tissues discovered four novel DAG pools, namely at: (i) the trans-Golgi network; (ii) the cell plate during cytokinesis; (iii) the plasma membrane of root epidermal cells in the transition zone, and (iv) the apex of growing root hairs. The results provide new insights into the spatiotemporal dynamics of DAG in plants and offer a new tool to monitor this in vivo.

Production of diacylglycerol‐enriched oils by enzymatic interesterification and molecular distillation using soybean oil and distilled saturated monoacylglycerol

The blend of refined soybean oil and distilled saturated monoacylglycerol in a mass ratio of 70: 30 w/w were enzymatically interesterified under the optimized enzyme dosage (5% w/w) and time (5 h) at 60°C, followed by further purification through molecular distillation (MD). All samples were evaluated and compared in terms of their iodine value (IV), acylglycerols, fatty acid composition, solid fat content (SFC), crystallization, and melting properties. The diacylglycerol content in the MD residual was found increased from 16.2% in interesterified oils to 22.6%. As the temperature increased, the SFC in the MD residual declined to the similar level of that in RSO. However, the crystallization onset temperature and melting point measured by differential scanning calorimetry were much higher than those of RSO. Moreover, the presence of β′ crystal was found in the MD residual by X‐ray diffraction and polarized light microscopy. In addition, the MD distillate had 27.4% of unsaturated fatty acids and the lowest IV amongst samples. Considering the properties above, the MD residual (diacylglycerol‐enriched oil) could be considered as plastic fats for fluid margarine and the MD distillate (by‐product) with 36.8 g/100 g of IV could be a potential emulsifier for oil and fat products.Practical applications: An innovative design for the production of diacylglycerol‐enriched oils was developed through optimized enzymatic interesterification and MD afterwards using oversupplied DSM and inexpensive RSO in China. On one hand, the resulting MD residual showed its promising application for fluid margarine because of its relatively high value in DAG, unsaturated fatty acid content, crystallization onset temperature, and melting point, as well as the existence of β′ crystal form found inside. On the other hand, the MD distillate as the MD by‐product may become a novel food emulsifier preferred by general consumers due to its lowest IV and enhanced unsaturated fatty acid content.The production of DAG‐enriched oils was developed using refined soybean oil (RSO) and distilled saturated monoacylglycerol (DSM) via coupling of optimized enzymatic interesterification and molecular distillation. The resulting MD residual and distillate were characterized by several physical and chemical analyses (e.g., GC‐FID, DSC, p‐NMR, XRD, and PLM) in order to prove their applicability for oil and fat products, especially in fluid margarine and food emulsification.

Preparation of Diacylglycerol from Lard by Enzymatic Glycerolysis and Its Compositional Characteristics.

The aim of this study was to prepare diacylglycerol (DAG) by enzymatic glycerolysis of lard. The effects of reaction parameters such as lipase type, reaction temperature, enzyme amount, substrate molar ratio (lard/glycerol), reaction time, and magnetic stirring speed were investigated. Lipozyme RMIM was found to be a more active biocatalyst than Novozym 435, and the optimal reaction conditions were 14:100 (W/W) of enzyme to lard substrate ratio, 1:1 of lard to glycerol molar ratio, and 500 rpm magnetic stirring speed. The reaction mixture was first incubated at 65℃ for 2 h and then transferred to 45℃ for 8 h. At the optimum reaction conditions, the conversion rate of triacylglycerol (TAG) and the content of DAG in the reaction mixture reached 76.26% and 61.76%, respectively, and the DAG content in purified glycerolized lard was 82.03% by molecular distillation. The distribution of fatty acids and Fourier transform infrared spectra in glycerolized lard samples were similar to those in lard samples. The results revealed that enzymatic glycerolysis and molecular distillation can be used to prepare more highly purified DAG from lard.

Diacylglycerol Accumulation Impairs Short-Term Activation of Phospholipase D by Thyroxine in the Liver Cells

Thyroid hormones (TG) are known modulators of signal transduction. Phospholipase D (PLD) is one of the targets of TG in the stimulated cells. Response of cells to the short-term TG action significantly reduces at old age. Taking into account that diacylglycerol (DAG) accumulation induces the resistance of cells to some of regulatory factors in the target cells the aim of the present study was to determine if DAG content increase in hepatocytes impairs the L-thyroxine (L-T4) short-term action. The experiments were performed in either the [14C]palmitic acid- labeled hepatocytes or [14C]oleic acid-pre-labeled liver cells of 3- and 24-month-old rats. To study the short-term L-T4 action on cells the PLD activation was determined. The DAG production and content in hepatocytes significantly increased at old age and in the young cells pre-treated with palmitic acid. The reduction of DAG level in cells by means of DAG-kinase activator, alfa-tocoferol acetate, or long-term L-T4 treatment improved the short-term hormone action. The above data have indicated that DAG play important role in the L-T4 PLD regulation. The cross-talk between classic and non-genomic pathways of TG regulation of lipid metabolism has been determined.

Modified Gas Chromatographic Method to Determine Monoacylglycerol and Diacylglycerol Contents in Edible Fats and Oils

Monoacylglycerol (MAG) and diacylglycerol (DAG) are minor components of edible fats and oils, and they relate to the quality of these foods. The AOCS official method Cd 11b-91 has been used to determine MAG and DAG contents in fats and oils. There are, however, difficulties in the determination of MAG and DAG using this analytical procedure. Therefore, we improved this method by modifying the trimethylsilyl derivatization procedure and replacing the internal standard (IS) material. In our modified method, TMS-HT (mixture of hexamethyldisilazane and trimethylchlorosilane) was used for derivatization of MAG and DAG, which was followed by liquid-liquid extraction with water and n-hexane solution containing the IS, tricaprin. Using the modified method, we demonstrated superior repeatability in comparison with that of the AOCS method by reducing procedural difficulties. The relative standard deviation of distearin peak areas was 1.8% or 2.9% in the modified method, while it was 5.6% in the AOCS method. In addition, capillary columns, such as DB-1ht and DB-5ht could be used in this method.

Changes in the Diaphragm Lipid Content after Administration of Streptozotocin and High-Fat Diet Regime.

The diaphragm is a dome-shaped skeletal muscle indispensable for breathing. Its activity contributes up to 70% of the total ventilatory function at rest. In comparison to other skeletal muscles, it is distinguished by an oxidative phenotype and uninterrupted cyclic contraction pattern. Surprisingly, the research regarding diaphragm diabetic phenotype particularly in the light of lipid-induced insulin resistance is virtually nonexistent. Male Wistar rats were randomly allocated into 3 groups: control, streptozotocin-induced (STZ) type-1 diabetes, and rodents fed with high-fat diet (HFD). Additionally, half of the animals from each group were administered with myriocin, a robust, selective inhibitor of ceramide synthesis and, therefore, a potent agent ameliorating insulin resistance. Diaphragm lipid contents were evaluated using chromatography. Fatty acid transporter expression was determined by Western blot. The STZ and HFD rats had increased concentration of lipids, namely, ceramides (CER) and diacylglycerols (DAG). Interestingly, this coincided with an increased concentration of long-chain (C ≥ 16) saturated fatty acid species present in both the aforementioned lipid fractions. The CER/DAG accumulation was accompanied by an elevated fatty acid transporter expression (FATP-1 in HFD and FATP-4 in STZ). Surprisingly, we observed a significantly decreased triacylglycerol content in the diaphragms of STZ-treated rats.

Calcium application enhances growth and alleviates the damaging effects induced by Cd stress in sesame (Sesamum indicum L.)

ABSTRACTIn this study, the effects of calcium (Ca2+) application on acquired systemic tolerance mechanism to cadmium (Cd) stress in sesame (Sesamum indicum L.) were studied. The Cd stress reduced the root and shoot growth of sesame, and plant contents of photosynthetic pigments; however, the application of Ca2+ improved these parameters under Cd stress condition. The hydrogen peroxide, malondialdehyde and soluble sugar contents were higher under Cd stress, and were reduced by Ca2+ treatment. The antioxidant enzyme activities in the leaves of sesame, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) were higher under Cd stress, whereas reduced concentration was observed in Ca2+-treated plants. Cd stress increased the contents of diacylglycerol and sterol ester; however Ca2+ treatment resulted in a significant increase in phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphatidylserine. Our results indicated that application of calcium enables sesame plants to withstand the deleterious impact of cadmium through upregulating acquired systemic tolerance system as lipid fractions (galactolipids, phospholipids, neutral lipids), antioxidant enzymes (SOD, POD, CAT, APX, GR) hence protect membrane functions.

Human Carboxylesterase 2 Reverses Obesity-Induced Diacylglycerol Accumulation and Glucose Intolerance

SummarySerine hydrolases are a large family of multifunctional enzymes known to influence obesity. Here, we performed activity-based protein profiling to assess the functional level of serine hydrolases in liver biopsies from lean and obese humans in order to gain mechanistic insight into the pathophysiology of metabolic disease. We identified reduced hepatic activity of carboxylesterase 2 (CES2) and arylacetamide deacetylase (AADAC) in human obesity. In primary human hepatocytes, CES2 knockdown impaired glucose storage and lipid oxidation. In mice, obesity reduced CES2, whereas adenoviral delivery of human CES2 reversed hepatic steatosis, improved glucose tolerance, and decreased inflammation. Lipidomic analysis identified a network of CES2-regulated lipids altered in human and mouse obesity. CES2 possesses triglyceride and diacylglycerol lipase activities and displayed an inverse correlation with HOMA-IR and hepatic diacylglycerol concentrations in humans. Thus, decreased CES2 is a conserved feature of obesity and plays a causative role in the pathogenesis of obesity-related metabolic disturbances.

Preparation of medium and long chain triacylglycerols by lipase-catalyzed interesterification in a solvent-free system

Abstract Synthesis of medium and long chain triacylglycerols (MLCTs) by lipase-catalyzed interesterification of soybean oil with medium chain triacylglycerols (MCTs) in a solvent-free system is investigated in this study. Firstly, reaction conditions of the interesterification were optimized. Under the optimum conditions (Lipozyme 435 of 8% as catalyst, substrate ratio of 40:60, heating temperature of 90 °C, reaction time of 6 h), MLCTs were obtained in a 74.9% yield Secondly, a two-step purification was conducted to reduce acid, peroxide values and diacylglycerol content to acceptable levels. After the deacidification by the neutralization and silica gel absorption, acid, peroxide values and diacylglycerol content were reduced to 0.14 mg/g, 1.5 mmol/kg and 1.2%, respectively. The determined levels of physicochemical parameters of purified MLCTs fell within the permitted ranges of the Chinese national standard specification for MLCTs. After a two-step purification, a qualified product was produced and can be used in pharmaceutical industry as a component of fat emulsion injection. The process for the preparation of MLCTs is scalable. Differently from previous studies, the aim of this study is to obtain MLCTs products meeting the national standard JX20070100 for structured triacylglycerols.