Phosphatidylethanolamine Fraction Research Articles

The Influence of APOE Genotype, DHA, and Flavanol Intervention on Brain DHA and Lipidomics Profile in Aged Transgenic Mice.

The apolipoprotein E4 (APOE4) genotype is predictive of Alzheimer's disease (AD). The brain is highly enriched with the omega-3 polyunsaturated fatty acid (n3-PUFA), docosahexaenoic acid (DHA). DHA's metabolism is defective in APOE4 carriers. Flavanol intake can play a role in modulating DHA levels. However, the impact of flavanol co-supplementation with fish oil on brain DHA uptake, status and partitioning, and according to APOE genotype is currently unknown. Here, using a humanised APOE3 and APOE4 targeted replacement transgenic mouse model, the interactive influence of cocoa flavanols (FLAV) and APOE genotype on the blood and subcortical brain PUFA status following the supplementation of a high fat (HF) enriched with DHA from fish oil (FO) was investigated. DHA levels increased in the blood (p < 0.001) and brain (p = 0.001) following supplementation. Compared to APOE3, a higher red blood cell (RBC) DHA (p < 0.001) was evident in APOE4 mice following FO and FLAV supplementation. Although FO did not increase the percentage of brain DHA in APOE4, a 17.1% (p < 0.05) and 20.0% (p < 0.001) higher DHA level in the phosphatidylcholine (PC) fraction in the HF FO and HF FO FLAV groups, and a 14.5% (p < 0.05) higher DHA level in the phosphatidylethanolamine (PE) fraction in the HF FO FLAV group was evident in these animals relative to the HF controls. The addition of FLAV (+/- FO) did not significantly increase the percentage of brain DHA in the group as a whole. However, a higher brain: RBC DHA ratio was evident in APOE3 only (p < 0.05) for HF FLAV versus HF. In conclusion, our data shows only modest effects of FLAV on the brain DHA status, which is limited to APOE3.

Characterization of polar and non-polar lipids of Hermetia illucens and Tenebrio molitor meals as animal feed ingredients

Although increasingly used in animal feeding, the black soldier fly (Hermetia illucens - HI) and mealworm (Tenebrio molitor - TM) larvae and pupae require the characterization and modulation of their fat profile for use in the feed industry. In this study, we provide a comprehensive fatty acid profile of the total lipid triglycerides and phospholipids, and sterol composition. For a more detailed characterization of the nutritional properties, we defined the profile of esterified fatty acids (FAs) in the sn-2 position of the triglycerides, which represents the most adsorbed fraction by animals during digestion. Twenty-four batches (12 batches per species divided into 6 batches of larvae and 6 batches of pupae) of 70 subjects were used for the analysis. For each of the developmental stages, individuals in the intermediate stage were considered (2 months and 8 days for TM larvae and pupae respectively; 9 days and 7 days for HI larvae and pupae respectively). Some fatty acids (decanoic, lauric, or myristic acid) were more abundant in HI than in TM. These FAs were produced de novo, indicating that HI produce them from carbohydrates as a source of acetyl-CoA. Hermetia illucens showed a higher level of conjugated linoleic acid (CLA) isomers, a class of fatty acids with positive health effects. In contrast, TM showed a similar fatty acid profile to the plant lipid source (such as soy and sunflower) due to the high level of linoleic acid. Analysis of the triglyceride fraction showed a different affinity for the three glyceride positions. In particular, lauric acid, polyunsaturated fatty acids n-3 and CLA isomers esterified preferentially in sn-2, and therefore were the most adsorbed by the animal during digestion. As for the phospholipids, HI showed a higher level, above all in terms of the phosphatidylethanolamine fraction. Interestingly there was no sphingomyelin in the pupae of both species. The high level of phospholipids is a useful feature for the emulsion of fats in animal feed diets. Lastly, we observed a considerable amount of phytosterol in the sterol profile of both species, which makes these insects a valid alternative to other food sources of plant origin for animal nutrition. We believe that our findings provide new nutritional information for the use of TM and HI in the animal diet.

The effect of the imbalance of the neurotransmitter systems of the dorsal hippocampus on the activity of alveolar macrophages and lung surfactant

The purpose of the study. The paper analyzes the metabolism of surfactant lipids and phagocytic activity of alveolar macrophages with an imbalance of the neurotransmitter systems of the dorsal hippocampus. Materials and methods. Male rats were microinjected with L-glutamate and GABA into the dorsal hippocampus bilaterally by stereotactic coordinates. Studies included determination of surfactant lipid fractions (thin-layer chromatography method), total phospholipids and their surface-active properties (Wilhelmi method), phospholipase activity, evaluation of endopulmonary cytogram, phagocytic index, and phagocytic number. Results. It was found that the introduction of L-glutamate was accompanied by an increase in phospholipids in the surfactant due to «inert» fractions of phosphatidylserine, phosphatidylinositol, and a low-active fraction of phosphatidylethanolamine against the background of a decrease in the intensity of phospholipase hydrolysis and the ability of macrophages to phagocytosis. The introduction of GABA led to redistribution of phospholipid fractions toward a decrease in phosphatidylcholine surfactant and an increase in the proportion of lysophosphatidylcholine under conditions of phospholipase activation and macrophage phagocytic activity. Conclusions The imbalance of the glutamate and GABAergic systems of the hippocampus has a multidirectional effect on the composition of surfactant lipids, the ability of alveolar macrophages to phagocytosis, and is characterized by the deterioration of the surface-active properties of the lungs.

The Changes in Composition of Phospholipid Subclasses Fatty Acids Prepared from Prediapausing and Postdiapausing Adults of Sunn Pest, Eurygaster integriceps Put. (Heteroptera: Scutelleridae)

Bu çalışmada, süne, Eurygaster integriceps’in diyapoz öncesi ergin ve diyapoz sonrası erginlerinin fosfatidilkolin (PC), fosfatidiletanolamin (PE), fosfatidilinositol (PI) ve fosfatidilserin (PS) gibi fosfolipit (PL) altsınıflarının yağ asidi kompozisyonundaki değişiklikler araştırılmıştır. Fosfolipit alt sınıflarının ayrılmasında İnce Tabaka Kromatoğrafisi tekniği, yağ asitlerinin analizinde ise Gaz kromatoğrafi cihazı kullanılmıştır. Eurygaster integriceps’in PL altsınıflarında gözlenen dominant yağ asitleri, doymuş yağ asitlerinden (SFA) palmitik asit (16:0), tekli doymamış yağ asitlerinden (MUFA) oleik asit (18:1n-9) ve çoklu doymamış yağ asitlerinden (PUFA) linoleik asit (18:2n-6) idi. Diyapoz öncesi ve diyapoz sonrası erginlerin PC, PE ve PS fraksiyonlarının yağ asidi içeriğindeki değişikliklerin benzer olduğu bulunmuştur. Diyapoz sonrası erginlerin bu fraksiyonlarında 16:0, 18:0 ve ∑SFA yüzdeleri diyapoz öncesi erginlere oranla daha düşük; ancak16:1n-7, ∑MUFA, 18:2n-6 ve ∑PUFA ise daha yüksek olarak bulunmuştur. Sünenin diyapoz sonrası bireylerin PE ve PC fraksiyonlarındaki 18:1n-9 düzeyi, diyapoz öncesi bireylerden önemli derecede daha yüksek olarak tespit edilmiştir. Diyapoz sonrası erginlerin tüm PL altsınıflarındaki doymamış yağ asitlerinin doymuş yağ asitlere oranı (UFA/SFA), diyapoz öncesi erginlerden daha yüksek bulunmuştur.

Fumonisin B1 induced compositional modifications of the renal and hepatic membrane lipids in rats – Dose and exposure time dependence

ABSTRACTMale Wistar rats were intraperitoneally dosed with fumonisin B1 (FB1; 0, 20, 50 and 100 mg kg−1 dietary dose equivalent) for 5 & 10 days to assess dose- and time-dependent effects on renal and hepatic phosphatidylcholine (PC), phosphatidylinositol (PI) and phosphatidylethanolamine (PE) fatty acid (FA) profiles. Renal PC showed increasing FA saturation (SAT) after 5 days; after 10 days polyunsaturation (PUFA) decreased markedly (Σ n3 (total n3), Σ n6, PUFA, unsaturation index (UI) and average FA chain length (ACL)), mostly with linear dose response. In the PI FAs similar changes were observed, decreasing monounsaturated FA, PUFA, UI and ACL (5 & 10 days), while the PE fraction was responsive in Σ n6 (↓) and SAT (↑), but only after 5 days (without dose response for both PI & PE). Liver PC exhibited increasing saturation (C16:0), decreasing polyunsaturation (C20:3 n6 [dihomo-γ-linolenic acid, DGLA]; C20:3 n3); the PI FA profile showed similar alterations after 5 days. PC & PI FA failed to respond in a dose-dependent manner to FB1. In PE FA profile DGLA decreased, with a decrease of the total n6 FA proportion and dose-dependent increase of n3 FAs. Results revealed expressed renal sensitivity, supporting our earlier published results in terms of oxidative stress and histopathological modifications.

The lipidome of primary murine white, brite, and brown adipocytes-Impact of beta-adrenergic stimulation.

Lipid species patterns are conserved within cells to maintain physicochemical properties of membranes and cellular functions. We present the lipidome, including sterols, glycerolipids (GLs), glycerophospholipids (GPLs), and sphingolipids (SLs), of primary ex vivo differentiated (I) white, (II) brite, and (III) brown adipocytes derived from primary preadipocytes isolated from (I) epididymal white, (II) inguinal white, and (III) intrascapular brown adipose tissue. Quantitative lipidomics revealed significantly decreased fractions of phosphatidylcholine (PC) and phosphatidylethanolamine (PE), with longer (C > 36) and more polyunsaturated species, as well as lower levels of cardiolipin (CL) in white than in brite and brown adipocytes. Together, the brite and brown lipidome was comparable and indicates differences in membrane lipid packing density compared with white adipocytes. Changes in ceramide species profile could be related to the degree of browning. Beta-adrenergic stimulation of brown adipocytes led to generation of saturated lyso-PC (LPC) increasing uncoupling protein (UCP) 1-mediated leak respiration. Application of stable isotope labeling showed that LPC formation was balanced by an increased de novo synthesis of PC.

The effect of silicon compounds on hematological indicators and content of lipids in blood of rabbits

The aim of the study was to find out the effect of casting of citrate nanosіlicon absorption and metasilicate sodium on the hematological parameters and lipid content and their fractional composition in blood plasma preparatory period 10 days prior to insemination and 20 days of lactation. The research was carried out on 60 rabbits of the Hyla hybrid, divided into three groups (control and two experimental), with 20 animals in each. The control animals were fed without limitation full-grain granulated feed with free access to water. Animals of the first experimental group (E-I) fed the diet of the control group and during the course of the day poured out the silicon citrate obtained using the nanotechnology method, 50 mkg Si/kg body weight with water. Samples of the second experimental group (E-II) feed the diet of the control group and set the sodium metasilicate (Na2SiO3H2O) 2.5 mg Si/kg body weight with water. The trial lasted 95 days, including the preparatory period of 10 days, the trial – 85 days. In the preparatory period of 10 days from the beginning of the study and in a trial of 20 days of lactation (65 days of supplements) in the rabbits, samples of blood from the marginal ear vein were taken. Hematologic studies were performed using the automatic hematologic analyzer “Orphee Mythic 18”, in the blood plasma, the content of total lipids and their fractional composition were determined. It was established that the number of erythrocytes and hemoglobin concentration in the blood of the rabbits of experimental group, which were given silicon citrate, were respectively higher by 15.2% (P &lt; 0.05) and 12.0% (P &lt; 0.01) by 20 days lactation versus control. This may indicate a more pronounced effect of the organic compound of silicon on the hematopoietic function of the body of the rabbits. According to white blood, the differences from control were found during the presentation of supplements with higher (P &lt; 0.05) changes in 20 days of lactation in animal blood and experimental group. It was noted that the content of triacylglycerols in plasma of blood of groups I and II was lower by 31.2 and 32.8%, respectively (P &lt; 0.05) compared to control. In blood plasma of animals in experimental groups an increase in the fractions of phosphatidylcholine, sphingomyelin and lysolecetin was observed compared to control. Such a redistribution was due to the reduction of the fractions of phosphatidic acid, phosphatidyl ethanolamine and phosphatidylinositol, and apparently, is associated with changes in the activity of the enzymes concerned. Hematological studies and determination of the fractional composition of lipids and phospholipids of blood plasma of the rabbits show positive changes that contribute to the metabolic accumulation of energy and plastic components of their organism.

Similarities in Blood Mononuclear Cell Membrane Phospholipid Profiles During Malignancy.

Phospholipids (PLs), key elements of cellular membranes, are regulated reciprocally with membrane proteins and can act as sensors for alterations in physiological or pathological states of cells including initiation and development of cancer. On the other hand, peripheral blood mononuclear cells (MNCs) play an important role in antitumor immune response by reacting to cancerous modifications in distant organs. In the current study, we tested the hypothesis that tumor initiation and development are reflected in the alteration pattern of the MNC PL component. We analyzed MNC membrane PL fractions in samples from healthy individuals and from patients with diverse types of cancers to reveal possible alterations induced by malignancy. Compared to healthy controls, the cancer samples demonstrated shifts in several membrane PL profiles. In particular, when analyzing cancer data pooled together, there were significantly higher levels in lysophosphatidylcholine, phosphatidylcholine, and phosphatidylethanolamine fractions, and significantly lower quantities in phosphatidylinositol, phosphatidylserine, and phosphatidic acid fractions in cancer samples compared to controls. The levels of sphingomyelins and diphosphatidylglycerols were relatively unaffected. Most of the differences in PLs were sustained during the analysis of individual cancers such as breast cancer and chronic lymphocytic leukemia. Our findings suggest the presence of a common pattern of changes in MNC PLs during malignancy.

Modulation of key lipid raft constituents in primary rat hepatocytes by fumonisin B1 - Implications for cancer promotion in the liver

Fumonisin B1 (FB1), a group 2B natural occurring carcinogenic mycotoxin, modulated lipid and fatty acid (FA) constituents of lipid rafts isolated from primary hepatocytes following exposure to a cytotoxic concentration of FB1 (250 μM). The major effects observed in rafts, included a significant (p < 0.05) increase in raft cholesterol (CHOL) and glycerophospholipid such as phosphatidylethanolamine (PE), whereas sphingomyelin (SM) decreased (p < 0.05). Changes in lipid constituents resulted in the disruption of important membrane fluidity parameters represented as a decreased (p < 0.05) in the phosphatidylcholine (PC)/PE and PC/(PE+SM) ratios and an increase (p < 0.05) in the CHOL/PL (PL=PC+PE) ratio, suggesting the preservation of lipid raft rigidity and integrity. Observed FA changes in the raft PE fraction included a significant (p < 0.05) increase in C18:2ω-6, C20:3ω-6, C20:4ω-6, C22:4ω-6, C22:5ω-3 and C22:6ω-3, with an increase in total ω-6 and ω-3 polyunsaturated fatty acids (PUFAs). Modulation of the FA content in PE, specifically the C20:4ω-6 PC/PE ratio and PUFA levels, together with changes in CHOL and SM are key determinants regulating the integrity and function of lipid rafts. In primary hepatocytes these changes are associated with the inhibition of cell proliferation and induction of apoptosis. A lipogenic mechanism is proposed whereby FB1 modulates lipid rafts and differentially target cell survival indices of normal and preneoplastic hepatocytes during cancer promotion in the liver.

Analysis of phosphatidylethanolamine, phosphatidylcholine, and plasmalogen molecular species in food lipids using an improved 2D high-performance liquid chromatography system

Phospholipids are an important class of lipids in cell membranes and food. Several high-performance liquid chromatography (HPLC) methods have been developed to analyze phospholipids at the molecular species level. We developed a two-dimensional HPLC system with a charged aerosol detector and mass spectrometry (MS) to analyze phosphatidylethanolamine (PE), phosphatidylcholine (PC), and their plasmalogens (pls) extracted from food materials. Accordingly, the phospholipid molecular species can be analyzed in a single step despite using smaller samples. We confirmed that chromatogram peaks from soybean lecithin are mostly baseline separated, assigned, and quantified (24 molecular species for PE and 27 for PC). In addition, it was confirmed that chromatograms of lipids extracted from chicken breast meat include plasmalogen peaks. The PE fraction in lipids extracted from chicken breast meat contained 17 types of ethanolamine plasmalogens, corresponding to approximately 57% of the total by weight. The PC fraction contained only four choline plasmalogens, corresponding to approximately 11% of the total weight. The composition of the pls-PC molecular species differed from that of pls-PEs. The polyunsaturated fatty acids connected at the sn-2 positions of the pls-PEs consisted of 20.5% 20:4 fatty acid and were independent of the carbon chain at the sn-1 position. However, the 18:1 fatty acid at the sn-2 position was dependent on the carbon chain at the sn-1 position.

Changes in lipids of shrimp (Acetes vulgaris) during salting and fermentation

Changes in lipids of shrimp Acetes vulgaris during production of Kapi (salted shrimp paste of Thailand) were investigated. Shrimp had lipid content of 4.21% (dry weight basis). Lipids mainly consisted of triacylglycerol (TAG) 28.03 g/100 g and sterol (ST) 24.03 g/100 g. Lipid content decreased during salting, drying and the first period of fermentation (p &lt; 0.05). Both TAG and ST gradually decreased, while free fatty acid (FFA) increased and became dominant in the final product (49.29%). Phospholipids including phosphatidylethanolamine (PE) 4.80 g/100 g and phosphatidylcholine (PC) 5.67 g/100 g were also found in fresh shrimp and still remained in the final product. Palmitic acid (C16:0) was the major fatty acid in shrimp (27.95%). Eicosapentaenoic acid (EPA) (C20:5(n‐3)) and docosahexaenoic acid (DHA) (C22:6(n‐3)) were found at high content (19.03%). When different fractions were isolated from crude lipids, varying fatty acid profiles were obtained. TAG and FFA fractions mainly consisted of saturated and monounsaturated fatty acids. Polyunsaturated fatty acids were accumulated in PE and PC fractions. Peroxide value and TBARS value increased during Kapi production, suggesting that lipid oxidation took place. Overall, lipolysis and oxidation of shrimp lipids occurred throughout the processes, thereby affecting lipid constituents. Those changes might partially contribute to the Kapi characteristics, especially flavor.Practical applications: Kapi, salted shrimp paste, is one of the most popular traditional condiments used in Thailand. Over the last decade, shrimp Acetes vulgaris, by‐catch from commercial fishing, has become the alternative raw material for Kapi production instead of krill (Mesopodopsis spp.). During processing, changes in lipids via both lipolysis and lipid oxidation occurred. This work provides the information about lipids from this shrimp species and their changes during Kapi production, which might determine sensory properties, especially odor or flavor, as well as nutritive value of the final product.Lipids of shrimp Acetes vulgaris, alternative source for Kapi production, consisted of TAG and ST as dominant lipids. PUFA was accumulated in PE and PC fractions, while TAG had SFA and MUFA as dominant fatty acids. During making Kapi, both lipolysis and lipid oxidation occurred, as indicated by the increases in FFA content and lipid oxidation products, respectively. These changes could be related with the final Kapi characteristics, and its nutritional value.

Omega-6 to omega-3 polyunsaturated fatty acid ratio and subsequent mood disorders in young people with at-risk mental states: a 7-year longitudinal study

While cross-sectional studies suggest that patients with mood disorders have a higher ratio of omega-6 to omega-3 polyunsaturated fatty acids (PUFAs) and lower levels of omega-3 PUFAs, it is unknown if a high n-6/3 ratio indicates vulnerability for depression. We tested this hypothesis in a 7-year follow-up study of young individuals with an ultra-high risk (UHR) phenotype. We conducted a secondary analysis of the Vienna omega-3 study, a longitudinal study of omega-3 PUFAs in individuals at UHR for psychosis (n=69). Levels of n-6 and n-3 PUFAs were measured in the phosphatidylethanolamine fraction of erythrocyte membranes at intake into the study. Mood disorder diagnosis was ascertained with the Structured Clinical Interview for DSM-IV-TR and confirmed by review of medical records and interviews of caregivers. A higher n-6/3 PUFA ratio at baseline predicted mood disorders in UHR individuals over a 7-year (median) follow-up (odds ratio=1.89, 95% CI=1.075–3.338, P=0.03). This association remained significant after adjustment for age, gender, smoking, severity of depressive symptoms at baseline and n-3 supplementation. Consistent results were obtained for individual PUFAs, including lower levels of eicosapentaenoic acid and docosahexaenoic acid. The predictive capacity of these findings was specific to mood disorders as no associations were found for any other psychiatric disorder. To our knowledge, our data provide the first prospective evidence that the n-6/3 PUFA ratio is associated with an increased risk for mood disorders in young people exhibiting an UHR phenotype. These findings may have important implications for treatment and risk stratification beyond clinical characteristics.

Bioactive fatty acids in mantis shrimp, crab and caramote prawn: Their content and distribution among the main lipid classes

The profile and distribution of fatty acids in neutral lipids, phosphatidylethanolamine and phosphatidylcholine of appreciated crustaceans species caught in the Adriatic Sea during the autumn months, namely caramote prawn (Penaeus kerathurus), mantis shrimp (Squilla mantis) and crab (Liocarcinus vernalis), were investigated. The crab’s total fatty acid profile significantly differed from that of caramote prawn and mantis shrimp. Crab was the most valuable dietary source of omega-3 polyunsaturated fatty acids (n–3 PUFA), with approximately 2-fold higher eicosapentaenoic acid content (131.6±31.6mg/100g of edible part) than caramote prawn and mantis shrimp. The caramote prawn presented the highest furan fatty acids (F-acids) level (2.5±0.5mg/100g). All crustaceans preferentially accumulated the n–3 PUFA in phosphatidylethanolamine fraction. The F-acid distribution among the lipid classes changed according to the crustacean species. Crab presented F-acids mainly in the neutral lipid whereas caramote prawn contained them predominantly in the phospholipids. On the contrary, F-acids were not detected in the phosphatidylcholine of mantis shrimp. These differences in the distribution suggest different nutritional and health properties given by the consumption of the crustaceans investigated. Moreover, the F-acid profile of the different lipid classes could be used to discriminate these crustaceans.

Homeostasis of phospholipids — The level of phosphatidylethanolamine tightly adapts to changes in ethanolamine plasmalogens

Ethanolamine plasmalogens constitute a group of ether glycerophospholipids that, due to their unique biophysical and biochemical properties, are essential components of mammalian cellular membranes. Their importance is emphasized by the consequences of defects in plasmalogen biosynthesis, which in humans cause the fatal disease rhizomelic chondrodysplasia punctata (RCDP). In the present lipidomic study, we used fibroblasts derived from RCDP patients, as well as brain tissue from plasmalogen-deficient mice, to examine the compensatory mechanisms of lipid homeostasis in response to plasmalogen deficiency. Our results show that phosphatidylethanolamine (PE), a diacyl glycerophospholipid, which like ethanolamine plasmalogens carries the head group ethanolamine, is the main player in the adaptation to plasmalogen insufficiency. PE levels were tightly adjusted to the amount of ethanolamine plasmalogens so that their combined levels were kept constant. Similarly, the total amount of polyunsaturated fatty acids (PUFAs) in ethanolamine phospholipids was maintained upon plasmalogen deficiency. However, we found an increased incorporation of arachidonic acid at the expense of docosahexaenoic acid in the PE fraction of plasmalogen-deficient tissues. These data show that under conditions of reduced plasmalogen levels, the amount of total ethanolamine phospholipids is precisely maintained by a rise in PE. At the same time, a shift in the ratio between ω-6 and ω-3 PUFAs occurs, which might have unfavorable, long-term biological consequences. Therefore, our findings are not only of interest for RCDP but may have more widespread implications also for other disease conditions, as for example Alzheimer's disease, that have been associated with a decline in plasmalogens.

Omega-3 phospholipids from fish suppress hepatic steatosis by integrated inhibition of biosynthetic pathways in dietary obese mice

Non-alcoholic fatty liver disease (NAFLD) accompanies obesity and insulin resistance. Recent meta-analysis suggested omega-3 polyunsaturated fatty acids DHA and EPA to decrease liver fat in NAFLD patients. Anti-inflammatory, hypolipidemic, and insulin-sensitizing effects of DHA/EPA depend on their lipid form, with marine phospholipids showing better efficacy than fish oils. We characterized the mechanisms underlying beneficial effects of DHA/EPA phospholipids, alone or combined with an antidiabetic drug, on hepatosteatosis. C57BL/6N mice were fed for 7weeks an obesogenic high-fat diet (cHF) or cHF-based interventions: (i) cHF supplemented with phosphatidylcholine-rich concentrate from herring (replacing 10% of dietary lipids; PC), (ii) cHF containing rosiglitazone (10mg/kg diet; R), or (iii) PC+R. Metabolic analyses, hepatic gene expression and lipidome profiling were performed. Results showed that PC and PC+R prevented cHF-induced weight gain and glucose intolerance, while all interventions reduced abdominal fat and plasma triacylglycerols. PC and PC+R also lowered hepatic and plasma cholesterol and reduced hepatosteatosis. Microarray analysis revealed integrated down-regulation of hepatic lipogenic and cholesterol biosynthesis pathways by PC, while R-induced lipogenesis was fully counteracted in PC+R. Gene expression changes in PC and PC+R were associated with preferential enrichment of hepatic phosphatidylcholine and phosphatidylethanolamine fractions by DHA/EPA. The complex down-regulation of hepatic lipogenic and cholesterol biosynthesis genes and the antisteatotic effects were unique to DHA/EPA-containing phospholipids, since they were absent in mice fed soy-derived phosphatidylcholine. Thus, inhibition of lipid and cholesterol biosynthesis associated with potent antisteatotic effects in the liver in response to DHA/EPA-containing phospholipids support their use in NAFLD prevention and treatment.

Validation of liposomal lipid composition by thin-layer chromatography

Liposomes of different sizes are frequently used model systems for cellular membranes. To mimic the cellular environment, these liposomes are often prepared from a mixture of different lipids in organic solution. The preparation involves, at some point, the transfer into aqueous solution. Thus, both the total amount of lipid and the relative amount of each lipid species might deviate from the original composition in the organic solvent. We used thin-layer chromatography combined with a lipid extraction step to check whether the liposomes in the final aqueous solution have the intended composition. This allows determination of the lipid composition not only for large unilamellar vesicles, but was also applied, for the first time, to giant lamellar vesicles (GUVs), which typically are available only with a low amount of lipid per preparation. For different ternary and quaternary mixtures of cholesterol, phosphatidylethanolamine, phosphatidylserine, phosphatidylcholine, and sphingomyelin, the final composition agreed within 15% with the intended composition in most cases, but in certain cases, such as GUVs prepared with a large fraction of phosphatidylethanolamine, the deviation can be significant. This shows that in those cases where the composition plays an important role, it is advisable to check the final composition of these model membranes.

Influence of gender on DHA synthesis: the response of rat liver to low dietary α-linolenic acid evidences higher ω3 ∆4-desaturation index in females

The conversion rate of α-linolenic acid (ALA) into docosahexaenoic acid (DHA) is determined by dietary and non-dietary factors. Higher capacity of DHA synthesis has been evidenced in females, indicating that sex factors influence the conversion pathway. To evaluate the extent to which sexual dimorphism of DHA synthesis is subordinated to nutritional handling, we measured the ω3 ∆4-desaturation index in male and female rats receiving adequate or inadequate amounts of ALA. The ω3 ∆4-desaturation index was drawn from the DHA to docosapentaenoic acid (ω3DPA) ratio in liver phospholipids. Male and female rats born to ω3-deficient dams were fed a supplemented diet supplying low, inadequate, intermediate, or adequate ALA (5, 20, 100, or 300mg ALA/100g diet, respectively). Control rats from both gender received the adequate diet from fetal life. Compared with control, low ALA feeding induced the ω3 ∆4-desaturation index to increase by 38 and 70% in the phosphatidylethanolamine fraction of males and females, respectively, and by 67% in phosphatidylcholine in females only. Supplementations with increased doses of ALA progressively smoothed this gender effect. Moreover, the analysis of our data from a previous study shows that ovariectomy decreased, whereas estradiol treatment increased the ω3 index to values comparable with those of diet-matched males and intact females, respectively. Females are more prone than males to increase their index of ω3 ∆4-desaturation, especially in response to low supplies in ALA. Estradiol supports the ω3 index, suggesting that this hormone plays a role in the effect of gender on DHA synthesis.

Up-regulated expression of desaturase genes of Mucor rouxii in response to low temperature associates with pre-existing cellular fatty acid constituents

Transcriptional response of desaturase genes to low temperature was investigated in the dimorphic fungus Mucor rouxii. The two morphological forms of M. rouxii, yeast-like and mycelial cells containing different fatty acid profiles were shifted from 30 to 10°C. Both cultures exhibited significantly altered fatty acid composition, whose content in polyunsaturated fatty acids increased as consequence of the temperature shift and was accompanied by a reduction of C18:1Δ(9) about 2 h after the temperature shift. These changes were particularly significant in phosphatidylcholine and phosphatidylethanolamine fractions. Moreover, the fatty acid profiles of monoacylglycerol and diacylglycerol were also modulated in response to the lower temperature of incubation. The changes of membrane lipids of M. rouxii were due to the cold-induced expression of Δ(9)-, Δ(12)- and Δ(6)-desaturase genes. Although the mRNA levels of the three desaturases were transiently induced by lowering the temperature, the pre-existing composition of fatty acid profiles of mycelial and yeast-like forms of M. rouxii may have lead to different expression profiles of desaturase genes that modified their membrane physical state under cold shock. While expression of Δ(12)-desaturase gene contributed mainly to cold acclimation of mycelia, Δ(9)-desaturase expression was the main transcript identified in the yeast-like culture after temperature shift.

Liposome−Hydrogel Bead Complexes Prepared via Biotin−Avidin Conjugation

Liposomes immobilized onto polymeric hydrogel microbeads have potential advantages both in tissue engineering applications and as drug delivery vehicles. Here we demonstrate, quantify, and optimize lipid vesicle binding to polymeric hydrogel microbeads via the avidin-biotin conjugation system and characterize the stability of the resulting microgel-bound liposomes. Microgels consisting of a copolymer of N-isopropylacrylamide (NIPAM) and acrylic acid (AA), cross-linked with bis-acrylamide, that is, p(NIPAM-co-AA), were biotinylated using aqueous carbodiimide chemistry. Extruded liposomes consisting of 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) plus a small fraction of a biotin-derivatized phosphatidylethanolamine (B-PE) were saturated with avidin and allowed to bind to biotinylated hydrogel beads. Using a combination of fluorescence spectroscopy, quenching, and microscopy and 31P NMR static and magic angle spinning (MAS) spectroscopies, we demonstrate conditions for near-quantitative liposome binding to p(NIPAM-co-AA) microbeads and show that liposome fusion does not occur under such conditions, that the liposomes remain intact and impermeable when so bound, and that they can function as slow release vehicles for entrapped aqueous species.

Opposing effects of methylmercury and n‐3 long‐chain polyunsaturated fatty acids on adult rat brain essential fatty acids

The objective was to assess interactive effects of methylmercury (MeHg) and n‐3 long‐chain polyunsaturated fatty acids (LCPUFA) on brain essential fatty acids in animals exposed chronically to MeHg and fed a diet with (+) or (‐) without n‐3 LCPUFA. Female rats (n=8/grp) were exposed for 1 yr to 0, 0.5, &amp; 5 ppm MeHg in water and consumed a diet containing palm, safflower, soybean and either coconut in (‐) n‐3 diet or fish oil in (+) n‐3 diet. Fatty acids of the phosphatidylcholine (PC) and phosphatidyl‐ethanolamine (PE) fractions of the adult rat brain were determined by gas capillary chromatography. In the adult forebrain, chronic MeHg exposure had no significant effects on the alteration of the major LCPUFA; docosahexaenoic acid (DHA) and arachidonic acid (ARA), as well as total n‐3 and total n‐6 fatty acids. However, there was a dietary effect showing a significant increase in DHA in both the PE (23‐30% increase) and PC (25‐46% increase) fractions in animals consuming dietary fish oil compared with those consuming the coconut oil diet (P&lt;0.001). There were significant decreases of ARA in both the PE (18‐20% decrease) and PC (12‐28% decrease) fractions. Thus, fatty acids in the adult rat brain can be influenced by long‐term feeding of dietary fish oil, but chronic mercury exposure had no effect on brain LCPUFA. (Funded by AAES 13‐014)