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Sample records for sleep-inducing lipid oleamide

  1. Enhanced radiosensitization of p53 mutant cells by oleamide

    SciTech Connect

    Lee, Yoon-Jin; Chung, Da Yeon; Lee, Su-Jae; Ja Jhon, Gil; Lee, Yun-Sil . E-mail: yslee@kcch.re.kr

    2006-04-01

    Purpose: Effect of oleamide, an endogenous fatty-acid primary amide, on tumor cells exposed to ionizing radiation (IR) has never before been explored. Methods and Materials: NCI H460, human lung cancer cells, and human astrocytoma cell lines, U87 and U251, were used. The cytotoxicity of oleamide alone or in combination with IR was determined by clonogenic survival assay, and induction of apoptosis was estimated by FACS analysis. Protein expressions were confirmed by Western blotting, and immunofluorescence analysis of Bax by use of confocal microscopy was also performed. The combined effect of IR and oleamide to suppress tumor growth was studied by use of xenografts in the thighs of nude mice. Results: Oleamide in combination with IR had a synergistic effect that decreased clonogenic survival of lung-carcinoma cell lines and also sensitized xenografts in nude mice. Enhanced induction of apoptosis of the cells by the combined treatment was mediated by loss of mitochondrial membrane potential, which resulted in the activation of caspase-8, caspase-9, and caspase-3 accompanied by cytochrome c release and Bid cleavage. The synergistic effects of the combined treatment were more enhanced in p53 mutant cells than in p53 wild-type cells. In p53 wild-type cells, both oleamide and radiation induced Bax translocation to mitochondria. On the other hand, in p53 mutant cells, radiation alone slightly induced Bax translocation to mitochondria, whereas oleamide induced a larger translocation. Conclusions: Oleamide may exhibit synergistic radiosensitization in p53 mutant cells through p53-independent Bax translocation to mitochondria.

  2. Rare Case of Rapidly Worsening REM Sleep Induced Bradycardia

    PubMed Central

    Duba, Ayyappa S.; Jasty, Suneetha; Mahajan, Ankit; Kodadhala, Vijay; Khan, Raza; Rai, Prithviraj; Ghazvini, Mohammad

    2015-01-01

    Sinoatrial arrest also known as sinus pause occurs when sinoatrial node of the heart transiently ceases to generate the electrical impulse necessary for the myocardium to contract. It may last from 2.0 seconds to several minutes. Etiologies of sinoatrial arrest can be complex and heterogeneous. During rapid eye movement (REM) sleep, sinus arrests unrelated to apnea or hypopnea are very rare and only a few cases have been reported. Here we report a case of 36-year-old male with no significant past medical history who presented to our hospital after a syncopal episode at night. Physical examination showed no cardiac or neurological abnormalities and initial EKG and neuroimaging were normal. Overnight telemonitor recorded several episodes of bradyarrhythmia with sinus arrest that progressively lengthened over time. Sleep study was done which confirmed that sinus arrests occurred more during REM sleep and are unrelated to apnea or hypopnea. Electrophysiology studies showed sinus nodal dysfunction with no junctional escape, subsequently a dual chamber pacemaker placed for rapidly worsening case of REM sleep induced bradycardia. PMID:26351588

  3. Prostaglandin D2, a cerebral sleep-inducing substance in monkeys.

    PubMed Central

    Onoe, H; Ueno, R; Fujita, I; Nishino, H; Oomura, Y; Hayaishi, O

    1988-01-01

    The sleep-inducing effect of prostaglandin D2 (PGD2) was studied in five conscious male rhesus monkeys (Macaca mulatta) maintained in a 12-hr light/dark cycle. PGD2 was infused into the lateral or the third ventricle of the cerebrum slowly and continuously for 6 hr in the light period. Infusion of PGD2 into the lateral ventricle at 15-2250 pmol/min induced natural sleep as identified by electroencephalogram, electromyogram, electrooculogram, body temperature, heart rate, and animal behavior. Although sensitivity to PGD2 was slightly different among individual animals, the amount of total sleep time increased maximally up to 3- to 4-fold over the control level. PGD2 infused into the third ventricle induced effects similar to those observed for the lateral ventricular route, but infusion into the third ventricle was about 1000 times more effective than infusion into the lateral ventricle. In three monkeys, PGD2 increased the amount of sleep in a dose-dependent manner. Bell-shaped dose-response curves were observed for the other two monkeys. Infusion of prostaglandin E2 or F2 alpha into the lateral ventricle caused sedation but slightly reduced the amount of slow-wave sleep and produced increases in heart rate and body temperature. These findings suggest that endogenous PGD2 may be involved in the regulation of sleep by acting on the brain structures surrounding the third ventricle in the rhesus monkey. PMID:3163802

  4. Slow Wave Sleep Induced by GABA Agonist Tiagabine Fails to Benefit Memory Consolidation

    PubMed Central

    Feld, Gordon B.; Wilhelm, Ines; Ma, Ying; Groch, Sabine; Binkofski, Ferdinand; Mölle, Matthias; Born, Jan

    2013-01-01

    Study Objectives: Slow wave sleep (SWS) plays a pivotal role in consolidating memories. Tiagabine has been shown to increase SWS in favor of REM sleep without impacting subjective sleep. However, it is unknown whether this effect is paralleled by an improved sleep-dependent consolidation of memory. Design: This double-blind within-subject crossover study tested sensitivity of overnight retention of declarative neutral and emotional materials (word pairs, pictures) as well as a procedural memory task (sequence finger tapping) to oral administration of placebo or 10 mg tiagabine (at 22:30). Participants: Fourteen healthy young men aged 21.9 years (range 18-28 years). Measurements and Results: Tiagabine significantly increased the time spent in SWS and decreased REM sleep compared to placebo. Tiagabine also enhanced slow wave activity (0.5-4.0 Hz) and density of < 1 Hz slow oscillations during NREM sleep. Fast (12-15 Hz) and slow (9-12 Hz) spindle activity, in particular that occurring phase-locked to the slow oscillation cycle, was decreased following tiagabine. Despite signs of deeper and more SWS, overnight retention of memory tested after sleep the next evening (19:30) was generally not improved after tiagabine, but on average even lower than after placebo, with this impairing effect reaching significance for procedural sequence finger tapping. Conclusions: Our data show that increasing slow wave sleep with tiagabine does not improve memory consolidation. Possibly this is due to functional differences from normal slow wave sleep, i.e., the concurrent suppressive influence of tiagabine on phase-locked spindle activity. Citation: Feld GB; Wilhelm I; Ma Y; Groch S; Binkofski F; Mölle M; Born J. Slow wave sleep induced by GABA agonist tiagabine fails to benefit memory consolidation. SLEEP 2013;36(9):1317-1326. PMID:23997364

  5. Effect of Leu-enkephalin and delta sleep inducing peptide (DSIP) on endogenous noradrenaline release by rat brain synaptosomes

    SciTech Connect

    Lozhanets, V.V.; Anosov, A.K.

    1986-01-01

    The nonapeptide delta-sleep inducing peptide (DSIP) causes specific changes in the encephalogram of recipient animals: It prolongs the phase of long-wave or delta sleep. The cellular mechanism of action of DSIP has not yet been explained. To test the hyporhesis that this peptide or its degradation product may be presynaptic regulators of catecholamine release, the action of Leu-enkephaline, DSIP, and amino acids composing DSIP on release of endogenous noradrenalin (NA) from synaptosomes during depolarization was compared. Subcellular fractions from cerebral hemisphere of noninbred male albino rats were isolated. Lactate dehydrogenase activity was determined in the suspension of synaptosomes before and after addition of 0.5% Triton X-100. The results were subjected to statistical analysis, using the Wilcoxon-Mann-Whitney nonparametric test.

  6. Therapeutic effects of delta-sleep-inducing peptide (DSIP) in patients with chronic, pronounced pain episodes. A clinical pilot study.

    PubMed

    Larbig, W; Gerber, W D; Kluck, M; Schoenenberger, G A

    1984-01-01

    Experimental results suggested a modulation or 'programming' interaction of delta sleep-inducing peptide (DSIP) with endogenous opioid-peptidergic systems and exogenous intracerebrally or systemically administered morphine and amphetamine. The induction of cerebral MAO-A activity, a pronounced influence on the circadian rhythms of locomotion and intracerebral neurotransmitter as well as plasma protein and cortisol concentrations has been reported. DSIP was also shown to counteract experimentally induced stress situations in animals. An improvement of the psychomotor performance and the concentration capacity in humans beside sleep normalization and pronounced effects on withdrawal symptoms including pain states in alcoholics and opiate addicts was discovered. This encouraged a pilot study for a possible action of the peptide in humans suffering from chronic pronounced pain episodes. We investigated the therapeutic effect in 7 patients with migraine episodes and vasomotor headaches, chronic tinnitus and psychogenic pain attacks. The anamnestic (baseline) values were statistically compared with the katamnestic control period. DSIP lowered significantly the pain levels of 6 out of 7 patients after intravenous administration on 5 consecutive days followed by 5 injections every 48-72 h. Remarkably, a simultaneous significant reduction of the concomitantly occurring depressive states was observed. PMID:6548970

  7. Degradation and aggregation of delta sleep-inducing peptide (DSIP) and two analogs in plasma and serum

    SciTech Connect

    Graf, M.V.; Saegesser, B.; Schoenenberger, G.A.

    1987-07-01

    The biostability of DSIP (delta sleep-inducing peptide) and two analogs in blood was investigated in order to determine if rates of inactivation contribute to variable effects in vivo. Incubation of DSIP in human or rat blood led to release of products having retention times on a gel filtration column equivalent to Trp. Formation of products was dependent on temperature, time, and species. Incubation of /sup 125/I-N-Tyr-DSIP and /sup 125/I-N-Tyr-P-DSIP, a phosphorylated analog, revealed slower degradation and, in contrast to DSIP, produced complex formation. An excess of unlabeled material did not displace the radioactivity supporting the assumption of non-specific binding/aggregation. It was concluded that the rapid disappearance of injected DSIP in blood was due to degradation, whereas complex formation together with slower degradation resulted in longer persistence of apparently intact analogs. Whether this could explain the sometimes stronger and more consistent effects of DSIP-analogs remains to be examined.

  8. OAT LIPIDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oat has a higher lipid concentration than other cereals, and the lipid concentration is genetically controlled and highly heritable. Millers prefer low lipid oats, to minimize both storage problems and fat calories in food products, whereas for animal feed, high-lipid oat is preferred because of th...

  9. Keys to Lipid Selection in Fatty Acid Amide Hydrolase Catalysis: Structural Flexibility, Gating Residues and Multiple Binding Pockets

    PubMed Central

    Palermo, Giulia; Bauer, Inga; Campomanes, Pablo; Cavalli, Andrea; Armirotti, Andrea; Girotto, Stefania; Rothlisberger, Ursula; De Vivo, Marco

    2015-01-01

    The fatty acid amide hydrolase (FAAH) regulates the endocannabinoid system cleaving primarily the lipid messenger anandamide. FAAH has been well characterized over the years and, importantly, it represents a promising drug target to treat several diseases, including inflammatory-related diseases and cancer. But its enzymatic mechanism for lipid selection to specifically hydrolyze anandamide, rather than similar bioactive lipids, remains elusive. Here, we clarify this mechanism in FAAH, examining the role of the dynamic paddle, which is formed by the gating residues Phe432 and Trp531 at the boundary between two cavities that form the FAAH catalytic site (the “membrane-access” and the “acyl chain-binding” pockets). We integrate microsecond-long MD simulations of wild type and double mutant model systems (Phe432Ala and Trp531Ala) of FAAH, embedded in a realistic membrane/water environment, with mutagenesis and kinetic experiments. We comparatively analyze three fatty acid substrates with different hydrolysis rates (anandamide > oleamide > palmitoylethanolamide). Our findings identify FAAH’s mechanism to selectively accommodate anandamide into a multi-pocket binding site, and to properly orient the substrate in pre-reactive conformations for efficient hydrolysis that is interceded by the dynamic paddle. Our findings therefore endorse a structural framework for a lipid selection mechanism mediated by structural flexibility and gating residues between multiple binding cavities, as found in FAAH. Based on the available structural data, this exquisite catalytic strategy for substrate specificity seems to be shared by other lipid-degrading enzymes with similar enzymatic architecture. The mechanistic insights for lipid selection might assist de-novo enzyme design or drug discovery efforts. PMID:26111155

  10. Milk lipids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Milk fat conveys a number of desirable qualities to food, and various lipid components contribute to human nutrition and health. Over 96% of milk lipids consist of triacylglycerols, which contain a variety of fatty acids. Di- and monoacylglycerols, free fatty acids, sterols, and phospho-, glyco-,...

  11. Lipid Nanotechnology

    PubMed Central

    Mashaghi, Samaneh; Jadidi, Tayebeh; Koenderink, Gijsje; Mashaghi, Alireza

    2013-01-01

    Nanotechnology is a multidisciplinary field that covers a vast and diverse array of devices and machines derived from engineering, physics, materials science, chemistry and biology. These devices have found applications in biomedical sciences, such as targeted drug delivery, bio-imaging, sensing and diagnosis of pathologies at early stages. In these applications, nano-devices typically interface with the plasma membrane of cells. On the other hand, naturally occurring nanostructures in biology have been a source of inspiration for new nanotechnological designs and hybrid nanostructures made of biological and non-biological, organic and inorganic building blocks. Lipids, with their amphiphilicity, diversity of head and tail chemistry, and antifouling properties that block nonspecific binding to lipid-coated surfaces, provide a powerful toolbox for nanotechnology. This review discusses the progress in the emerging field of lipid nanotechnology. PMID:23429269

  12. Lipid Storage Diseases

    MedlinePLUS

    ... Awards Enhancing Diversity Find People About NINDS NINDS Lipid Storage Diseases Information Page Condensed from Lipid Storage ... en Español Additional resources from MedlinePlus What are Lipid Storage Diseases? Lipid storage diseases are a group ...

  13. Lipid antigens in immunity

    PubMed Central

    Dowds, C. Marie; Kornell, Sabin-Christin

    2014-01-01

    Lipids are not only a central part of human metabolism but also play diverse and critical roles in the immune system. As such, they can act as ligands of lipid-activated nuclear receptors, control inflammatory signaling through bioactive lipids such as prostaglandins, leukotrienes, lipoxins, resolvins, and protectins, and modulate immunity as intracellular phospholipid- or sphingolipid-derived signaling mediators. In addition, lipids can serve as antigens and regulate immunity through the activation of lipid-reactive T cells, which is the topic of this review. We will provide an overview of the mechanisms of lipid antigen presentation, the biology of lipid-reactive T cells, and their contribution to immunity. PMID:23999493

  14. Plant Lipid Rafts

    PubMed Central

    Furt, Fabienne; Lefebvre, Benoit; Cullimore, Julie; Bessoule, Jean-Jacques

    2007-01-01

    Lipid rafts in plasma membranes are hypothesized to play key roles in many cellular processes including signal transduction, membrane trafficking and entry of pathogens. We recently documented the biochemical characterization of lipid rafts, isolated as detergent-insoluble membranes, from Medicago truncatula root plasma membranes. We evidenced that the plant-specific lipid steryl-conjugates are among the main lipids of rafts together with free sterols and sphingolipids. An extensive proteomic analysis showed the presence of a specific set of proteins common to other lipid rafts, plus the presence of a redox system around a cytochrome b561 not previously identified in lipid rafts of either plants or animals. Here, we discuss the similarities and differences between the lipids and proteins of plant and animal lipid rafts. Moreover we describe the potential biochemical functioning of the M. truncatula root lipid raft redox proteins and question whether they may play a physiological role in legume-symbiont interactions. PMID:19704542

  15. LIPID MAPS online tools for lipid research

    PubMed Central

    Fahy, Eoin; Sud, Manish; Cotter, Dawn; Subramaniam, Shankar

    2007-01-01

    The LIPID MAPS consortium has developed a number of online tools for performing tasks such as drawing lipid structures and predicting possible structures from mass spectrometry (MS) data. A simple online interface has been developed to enable an end-user to rapidly generate a variety of lipid chemical structures, along with corresponding systematic names and ontological information. The structure-drawing tools are available for six categories of lipids: (i) fatty acyls, (ii) glycerolipids, (iii) glycerophospholipids, (iv) cardiolipins, (v) sphingolipids and (vi) sterols. Within each category, the structure-drawing tools support the specification of various parameters such as chain lengths at a specific sn position, head groups, double bond positions and stereochemistry to generate a specific lipid structure. The structure-drawing tools have also been integrated with a second set of online tools which predict possible lipid structures from precursor-ion and product-ion MS experimental data. The MS prediction tools are available for three categories of lipids: (i) mono/di/triacylglycerols, (ii) glycerophospholipids and (iii) cardiolipins. The LIPID MAPS online tools are publicly available at www.lipidmaps.org/tools/. PMID:17584797

  16. Daunorubicin Lipid Complex Injection

    MedlinePLUS

    Daunorubicin lipid complex is used to treat advanced Kaposi's sarcoma (a type of cancer that causes abnormal tissue to ... body) related to acquired immunodeficiency syndrome (AIDS). Daunorubicin lipid complex is in a class of medications called ...

  17. Vincristine Lipid Complex Injection

    MedlinePLUS

    Vincristine lipid complex is used to treat a certain type of acute lymphoblastic leukemia (ALL; a type of cancer ... least two different treatments with other medications. Vincristine lipid complex is in a class of medications called ...

  18. Doxorubicin Lipid Complex Injection

    MedlinePLUS

    Doxorubicin lipid complex is used to treat ovarian cancer that has not improved or that has worsened after treatment with other medications. Doxorubicin lipid complex is also used to treat Kaposi's sarcoma ( ...

  19. Microalgae lipid characterization.

    PubMed

    Yao, Linxing; Gerde, Jose A; Lee, Show-Ling; Wang, Tong; Harrata, Kamel A

    2015-02-18

    To meet the growing interest of utilizing microalgae biomass in the production of biofuels and nutraceutical and pharmaceutical lipids, we need suitable analytical methods and a comprehensive database for their lipid components. The objective of the present work was to demonstrate methodology and provide data on fatty acid composition, lipid class content and composition, characteristics of the unsaponifiables, and type of chlorophylls of five microalgae. Microalgae lipids were fractionated into TAG, FFA, and polar lipids using TLC, and the composition of fatty acids in total lipids and in each lipid class, hydrocarbons, and sterols were determined by GC-MS. Glyco- and phospholipids were profiled by LC/ESI-MS. Chlorophylls and their related metabolites were qualified by LC/APCI-MS. The melting and crystallization profiles of microalgae total lipids and their esters were analyzed by DSC to evaluate their potential biofuel applications. Significant differences and complexities of lipid composition among the algae tested were observed. The compositional information is valuable for strain selection, downstream biomass fractionation, and utilization. PMID:25608629

  20. Lipid Droplets And Cellular Lipid Metabolism

    PubMed Central

    Walther, Tobias C.; Farese, Robert V.

    2013-01-01

    Among organelles, lipid droplets (LDs) uniquely constitute a hydrophobic phase in the aqueous environment of the cytosol. Their hydrophobic core of neutral lipids stores metabolic energy and membrane components, making LDs hubs for lipid metabolism. In addition, LDs are implicated in a number of other cellular functions, ranging from protein storage and degradation to viral replication. These processes are functionally linked to many physiological and pathological conditions, including obesity and related metabolic diseases. Despite their important functions and nearly ubiquitous presence in cells, many aspects of LD biology are unknown. In the past few years, the pace of LD investigation has increased, providing new insights. Here, we review the current knowledge of LD cell biology and its translation to physiology. PMID:22524315

  1. Big, Fat World of Lipids

    MedlinePLUS

    ... Science Home Page The Big, Fat World of Lipids By Emily Carlson Posted August 9, 2012 Cholesterol ... ways to diagnose and treat lipid-related conditions. Lipid Encyclopedia Just as genomics and proteomics spurred advances ...

  2. Lysosomal lipid storage diseases.

    PubMed

    Schulze, Heike; Sandhoff, Konrad

    2011-06-01

    Lysosomal lipid storage diseases, or lipidoses, are inherited metabolic disorders in which typically lipids accumulate in cells and tissues. Complex lipids, such as glycosphingolipids, are constitutively degraded within the endolysosomal system by soluble hydrolytic enzymes with the help of lipid binding proteins in a sequential manner. Because of a functionally impaired hydrolase or auxiliary protein, their lipid substrates cannot be degraded, accumulate in the lysosome, and slowly spread to other intracellular membranes. In Niemann-Pick type C disease, cholesterol transport is impaired and unesterified cholesterol accumulates in the late endosome. In most lysosomal lipid storage diseases, the accumulation of one or few lipids leads to the coprecipitation of other hydrophobic substances in the endolysosomal system, such as lipids and proteins, causing a "traffic jam." This can impair lysosomal function, such as delivery of nutrients through the endolysosomal system, leading to a state of cellular starvation. Therapeutic approaches are currently restricted to mild forms of diseases with significant residual catabolic activities and without brain involvement. PMID:21502308

  3. Lipids: Absorption and transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lipid has long been recognized as an important dietary component. Dietary lipid (fat) is a critical source of metabolic energy and a substrate for the synthesis of metabolically active compounds (essential fatty acids), and serves as a carrier for other nutrients such as the fat-soluble vitamins A, ...

  4. Lipid-absorbing Polymers

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr.; Wallace, C. J.

    1973-01-01

    The removal of bile acids and cholesterol by polymeric absorption is discussed in terms of micelle-polymer interaction. The results obtained with a polymer composed of 75 parts PEO and 25 parts PB plus curing ingredients show an absorption of 305 to 309%, based on original polymer weight. Particle size effects on absorption rate are analyzed. It is concluded that crosslinked polyethylene oxide polymers will absorb water, crosslinked polybutadiene polymers will absorb lipids; neither polymer will absorb appreciable amounts of lipids from micellar solutions of lipids in water.

  5. Cytarabine Lipid Complex Injection

    MedlinePLUS

    Cytarabine lipid complex is used to treat lymphomatous meningitis (a type of cancer in the covering of ... to take.tell your doctor if you have meningitis. Your doctor will probably not want you to ...

  6. Metabolism. Part III: Lipids.

    ERIC Educational Resources Information Center

    Bodner, George M.

    1986-01-01

    Describes the metabolic processes of complex lipids, including saponification, activation and transport, and the beta-oxidation spiral. Discusses fatty acid degradation in regard to biochemical energy and ketone bodies. (TW)

  7. Acyl-Lipid Metabolism

    PubMed Central

    Li-Beisson, Yonghua; Shorrosh, Basil; Beisson, Fred; Andersson, Mats X.; Arondel, Vincent; Bates, Philip D.; Baud, Sébastien; Bird, David; DeBono, Allan; Durrett, Timothy P.; Franke, Rochus B.; Graham, Ian A.; Katayama, Kenta; Kelly, Amélie A.; Larson, Tony; Markham, Jonathan E.; Miquel, Martine; Molina, Isabel; Nishida, Ikuo; Rowland, Owen; Samuels, Lacey; Schmid, Katherine M.; Wada, Hajime; Welti, Ruth; Xu, Changcheng; Zallot, Rémi; Ohlrogge, John

    2013-01-01

    Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes that restricts the loss of water and provides protection from invasions by pathogens and other stresses covers the entire aerial surface of Arabidopsis. Similar functions are provided by suberin and its associated waxes that are localized in roots, seed coats, and abscission zones and are produced in response to wounding. This chapter focuses on the metabolic pathways that are associated with the biosynthesis and degradation of the acyl lipids mentioned above. These pathways, enzymes, and genes are also presented in detail in an associated website (ARALIP: http://aralip.plantbiology.msu.edu/). Protocols and methods used for analysis of Arabidopsis lipids are provided. Finally, a detailed summary of the composition of Arabidopsis lipids is provided in three figures and 15 tables. PMID:23505340

  8. Acyl-Lipid Metabolism

    PubMed Central

    Li-Beisson, Yonghua; Shorrosh, Basil; Beisson, Fred; Andersson, Mats X.; Arondel, Vincent; Bates, Philip D.; Baud, Sébastien; Bird, David; DeBono, Allan; Durrett, Timothy P.; Franke, Rochus B.; Graham, Ian A.; Katayama, Kenta; Kelly, Amélie A.; Larson, Tony; Markham, Jonathan E.; Miquel, Martine; Molina, Isabel; Nishida, Ikuo; Rowland, Owen; Samuels, Lacey; Schmid, Katherine M.; Wada, Hajime; Welti, Ruth; Xu, Changcheng; Zallot, Rémi; Ohlrogge, John

    2010-01-01

    Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes that restricts the loss of water and provides protection from invasions by pathogens and other stresses covers the entire aerial surface of Arabidopsis. Similar functions are provided by suberin and its associated waxes that are localized in roots, seed coats, and abscission zones and are produced in response to wounding. This chapter focuses on the metabolic pathways that are associated with the biosynthesis and degradation of the acyl lipids mentioned above. These pathways, enzymes, and genes are also presented in detail in an associated website (ARALIP: http://aralip.plantbiology.msu.edu/). Protocols and methods used for analysis of Arabidopsis lipids are provided. Finally, a detailed summary of the composition of Arabidopsis lipids is provided in three figures and 15 tables. PMID:22303259

  9. Lipid membranes for membrane proteins.

    PubMed

    Kukol, Andreas

    2015-01-01

    The molecular dynamics (MD) simulation of membrane proteins requires the setup of an accurate representation of lipid bilayers. This chapter describes the setup of a lipid bilayer system from scratch using generally available tools, starting with a definition of the lipid molecule POPE, generation of a lipid bilayer, energy minimization, MD simulation, and data analysis. The data analysis includes the calculation of area and volume per lipid, deuterium order parameters, self-diffusion constant, and the electron density profile. PMID:25330959

  10. Lipid injectable emulsions: 2006.

    PubMed

    Driscoll, David F

    2006-08-01

    Lipid injectable emulsions are an essential source of fatty acids, as well as a daily source of calories. They have been used in the clinical setting for almost 40 years, but despite this, there are no established official standards governing pharmaceutical quality. After 15 years of development, the United States Pharmacopeia (USP), which writes such standards for all FDA-approved pharmaceuticals, is poised to adopt an official monograph for lipid injectable emulsions that sets pharmaceutical requirements on all manufacturers placing limits on pH, free fatty acid concentrations and globule size (both mean droplet size and the population of large fat globules larger than 5 micrometers). Recent animal data has shown pathophysiologic changes in vital organs for lipids that fall outside the USP-proposed globule size limits. From a clinical perspective, newer lipid injectable emulsions show great promise in certain patient settings, most notably in the intensive care unit in both adults and infants. The clinical use of alternative oils, such as medium-chain triglycerides, fish oil and olive oil show benefits over conventional soybean oil formulations. In adults, for example, the administration of omega-fatty acids via soybean oil-based lipids produces a heightened inflammatory response via production of 2-series prostaglandins, whereas substitution of a portion of the lipid with omega-3 fatty acids via fish oil can favorably dampen the inflammatory response. In infants, for example, substitution of soybean oil with fish oil has recently been shown to reverse parenteral nutrition-associated liver disease. These advances should lead to safer infusion therapy in patients receiving lipid injectable emulsions. PMID:16870806

  11. Immobilized lipid-bilayer materials

    DOEpatents

    Sasaki, Darryl Y. (Albuquerque, NM); Loy, Douglas A. (Albuquerque, NM); Yamanaka, Stacey A. (Dallas, TX)

    2000-01-01

    A method for preparing encapsulated lipid-bilayer materials in a silica matrix comprising preparing a silica sol, mixing a lipid-bilayer material in the silica sol and allowing the mixture to gel to form the encapsulated lipid-bilayer material. The mild processing conditions allow quantitative entrapment of pre-formed lipid-bilayer materials without modification to the material's spectral characteristics. The method allows for the immobilization of lipid membranes to surfaces. The encapsulated lipid-bilayer materials perform as sensitive optical sensors for the detection of analytes such as heavy metal ions and can be used as drug delivery systems and as separation devices.

  12. Lipid nanotube or nanowire sensor

    DOEpatents

    Noy, Aleksandr (Belmont, CA); Bakajin, Olgica (San Leandro, CA); Letant, Sonia (Livermore, CA); Stadermann, Michael (Dublin, CA); Artyukhin, Alexander B. (Menlo Park, CA)

    2009-06-09

    A sensor apparatus comprising a nanotube or nanowire, a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer. Also a biosensor apparatus comprising a gate electrode; a source electrode; a drain electrode; a nanotube or nanowire operatively connected to the gate electrode, the source electrode, and the drain electrode; a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer.

  13. Lipid nanotube or nanowire sensor

    DOEpatents

    Noy, Aleksandr (Belmont, CA); Bakajin, Olgica (San Leandro, CA); Letant, Sonia (Livermore, CA); Stadermann, Michael (Dublin, CA); Artyukhin, Alexander B. (Menlo Park, CA)

    2010-06-29

    A sensor apparatus comprising a nanotube or nanowire, a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer. Also a biosensor apparatus comprising a gate electrode; a source electrode; a drain electrode; a nanotube or nanowire operatively connected to the gate electrode, the source electrode, and the drain electrode; a lipid bilayer around the nanotube or nanowire, and a sensing element connected to the lipid bilayer.

  14. Lipids: Absorption and transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the hydrophobic nature of lipids, dietary fat is handled differently than protein or carbohydrate with respect with digestion and absorption. Dietary fats are broken down throughout the gastrointestinal system. A unique group of enzymes and cofactors allows this process to proceed in an eff...

  15. Lipid droplets go nuclear.

    PubMed

    Farese, Robert V; Walther, Tobias C

    2016-01-01

    Lipid droplets (LDs) are sometimes found in the nucleus of some cells. In this issue, Ohsaki et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201507122) show that the nuclear membrane, promyelocytic leukemia bodies, and the protein PML-II play a role in nuclear LD formation, suggesting functional relationships between these structures. PMID:26728852

  16. LMSD: LIPID MAPS structure database

    PubMed Central

    Sud, Manish; Fahy, Eoin; Cotter, Dawn; Brown, Alex; Dennis, Edward A.; Glass, Christopher K.; Merrill, Alfred H.; Murphy, Robert C.; Raetz, Christian R. H.; Russell, David W.; Subramaniam, Shankar

    2007-01-01

    The LIPID MAPS Structure Database (LMSD) is a relational database encompassing structures and annotations of biologically relevant lipids. Structures of lipids in the database come from four sources: (i) LIPID MAPS Consortium's core laboratories and partners; (ii) lipids identified by LIPID MAPS experiments; (iii) computationally generated structures for appropriate lipid classes; (iv) biologically relevant lipids manually curated from LIPID BANK, LIPIDAT and other public sources. All the lipid structures in LMSD are drawn in a consistent fashion. In addition to a classification-based retrieval of lipids, users can search LMSD using either text-based or structure-based search options. The text-based search implementation supports data retrieval by any combination of these data fields: LIPID MAPS ID, systematic or common name, mass, formula, category, main class, and subclass data fields. The structure-based search, in conjunction with optional data fields, provides the capability to perform a substructure search or exact match for the structure drawn by the user. Search results, in addition to structure and annotations, also include relevant links to external databases. The LMSD is publicly available at PMID:17098933

  17. The SwissLipids knowledgebase for lipid biology

    PubMed Central

    Liechti, Robin; Hyka-Nouspikel, Nevila; Niknejad, Anne; Gleizes, Anne; Götz, Lou; Kuznetsov, Dmitry; David, Fabrice P.A.; van der Goot, F. Gisou; Riezman, Howard; Bougueleret, Lydie; Xenarios, Ioannis; Bridge, Alan

    2015-01-01

    Motivation: Lipids are a large and diverse group of biological molecules with roles in membrane formation, energy storage and signaling. Cellular lipidomes may contain tens of thousands of structures, a staggering degree of complexity whose significance is not yet fully understood. High-throughput mass spectrometry-based platforms provide a means to study this complexity, but the interpretation of lipidomic data and its integration with prior knowledge of lipid biology suffers from a lack of appropriate tools to manage the data and extract knowledge from it. Results: To facilitate the description and exploration of lipidomic data and its integration with prior biological knowledge, we have developed a knowledge resource for lipids and their biology—SwissLipids. SwissLipids provides curated knowledge of lipid structures and metabolism which is used to generate an in silico library of feasible lipid structures. These are arranged in a hierarchical classification that links mass spectrometry analytical outputs to all possible lipid structures, metabolic reactions and enzymes. SwissLipids provides a reference namespace for lipidomic data publication, data exploration and hypothesis generation. The current version of SwissLipids includes over 244?000 known and theoretically possible lipid structures, over 800 proteins, and curated links to published knowledge from over 620 peer-reviewed publications. We are continually updating the SwissLipids hierarchy with new lipid categories and new expert curated knowledge. Availability: SwissLipids is freely available at http://www.swisslipids.org/. Contact: alan.bridge@isb-sib.ch Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25943471

  18. Pharmacological Inhibition of Protein Lipidation.

    PubMed

    Ganesan, Lakshmi; Levental, Ilya

    2015-12-01

    Lipid modifications of mammalian proteins are widespread, modifying thousands of targets involved in all aspects of cellular physiology cellular physiology. Broadly, lipidations serve to increase protein hydrophobicity and association with cellular membranes. Often, these modifications are absolutely essential for protein stability and localization, and serve critical roles in dynamic regulation of protein function. A number of lipidated proteins are associated with diseases, including parasite infections, neurological diseases, diabetes, and cancer, suggesting that lipid modifications represent potentially attractive targets for pharmacological intervention. This review briefly describes the various types of posttranslational protein lipid modifications, proteins modified by them, and the enzymatic machinery associated with these. We then discuss several case studies demonstrating successful development of lipidation inhibitors of potential (and more rarely, realized) clinical value. Although this field remains in its infancy, we believe these examples demonstrate the potential utility of targeting protein lipidation as a viable strategy for inhibiting the function of pathogenic proteins. PMID:26280397

  19. Simplified lipid guidelines

    PubMed Central

    Allan, G. Michael; Lindblad, Adrienne J.; Comeau, Ann; Coppola, John; Hudson, Brianne; Mannarino, Marco; McMinis, Cindy; Padwal, Raj; Schelstraete, Christine; Zarnke, Kelly; Garrison, Scott; Cotton, Candra; Korownyk, Christina; McCormack, James; Nickel, Sharon; Kolber, Michael R.

    2015-01-01

    Abstract Objective To develop clinical practice guidelines for a simplified approach to primary prevention of cardiovascular disease (CVD), concentrating on CVD risk estimation and lipid management for primary care clinicians and their teams; we sought increased contribution from primary care professionals with little or no conflict of interest and focused on the highest level of evidence available. Methods Nine health professionals (4 family physicians, 2 internal medicine specialists, 1 nurse practitioner, 1 registered nurse, and 1 pharmacist) and 1 nonvoting member (pharmacist project manager) comprised the overarching Lipid Pathway Committee (LPC). Member selection was based on profession, practice setting, and location, and members disclosed any actual or potential conflicts of interest. The guideline process was iterative through online posting, detailed evidence review, and telephone and online meetings. The LPC identified 12 priority questions to be addressed. The Evidence Review Group answered these questions. After review of the answers, key recommendations were derived through consensus of the LPC. The guidelines were drafted, refined, and distributed to a group of clinicians (family physicians, other specialists, pharmacists, nurses, and nurse practitioners) and patients for feedback, then refined again and finalized by the LPC. Recommendations Recommendations are provided on screening and testing, risk assessments, interventions, follow-up, and the role of acetylsalicylic acid in primary prevention. Conclusion These simplified lipid guidelines provide practical recommendations for prevention and treatment of CVD for primary care practitioners. All recommendations are intended to assist with, not dictate, decision making in conjunction with patients. PMID:26472792

  20. Tear Film Lipids

    PubMed Central

    Butovich, Igor A.

    2013-01-01

    Human meibomian gland secretions (MGS, or meibum) are formed from a complex mixture of lipids of different classes such as wax esters, cholesteryl esters, (O-acyl)-?-hydroxy fatty acids (OAHFA) and their esters, acylglycerols, diacylated diols, free fatty acids, cholesterol, and a smaller amount of other polar and nonpolar lipids, whose chemical nature and the very presence in MGS have been a matter of intense debates. The purpose of this review is to discuss recent results that were obtained using different experimental techniques, estimate limitations of their usability, and discuss their biochemical, biophysical, and physiological implications. To create a lipid map of MGS and tears, the results obtained in the author’s laboratory were integrated with available information on chemical composition of MGS and tears. The most informative approaches that are available today to researchers, such as HPLC-MS, GC-MS, and proton NMR, are discussed in details. A map of the meibomian lipidome (as it is seen in reverse phase liquid chromatography/mass spectrometry experiments) is presented. Directions of future efforts in the area are outlined. PMID:23769846

  1. Cell-Based Lipid Flippase Assay Employing Fluorescent Lipid Derivatives.

    PubMed

    Jensen, Maria S; Costa, Sara; Günther-Pomorski, Thomas; López-Marqués, Rosa L

    2016-01-01

    P-type ATPases in the P4 subfamily (P4-ATPases) are transmembrane proteins unique for eukaryotes that act as lipid flippases, i.e., to translocate phospholipids from the exofacial to the cytofacial monolayer of cellular membranes. While initially characterized as aminophospholipid translocases, studies of individual P4-ATPase family members from fungi, plants, and animals show that P4-ATPases differ in their substrate specificities and mediate transport of a broader range of lipid substrates. Here, we describe an assay based on fluorescent lipid derivatives to monitor and characterize lipid flippase activities in the plasma membrane of cells, using yeast as an example. PMID:26695048

  2. RF Microalgal lipid content characterization

    PubMed Central

    Ahmad, Mahmoud Al; Al-Zuhair, Sulaiman; Taher, Hanifa; Hilal-Alnaqbi, Ali

    2014-01-01

    Most conventional techniques for the determination of microalgae lipid content are time consuming and in most cases are indirect and require excessive sample preparations. This work presents a new technique that utilizes radio frequency (RF) for rapid lipid quantification, without the need for sample preparation. Tests showed that a shift in the resonance frequency of a RF open-ended coaxial resonator and a gradual increase in its resonance magnitude may occur as the lipids content of microalgae cells increases. These response parameters can be then calibrated against actual cellular lipid contents and used for rapid determination of the cellular lipids. The average duration of lipid quantification using the proposed technique was of about 1 minute, which is significantly less than all other conventional techniques, and was achieved without the need for any time consuming treatment steps. PMID:24870372

  3. Lipid Biomembrane in Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Yoo, Brian; Jing, Benxin; Shah, Jindal; Maginn, Ed; Zhu, Y. Elaine; Department of Chemical and Biomolecular Engineering Team

    2014-03-01

    Ionic liquids (ILs) have been recently explored as new ``green'' chemicals in several chemical and biomedical processes. In our pursuit of understanding their toxicities towards aquatic and terrestrial organisms, we have examined the IL interaction with lipid bilayers as model cell membranes. Experimentally by fluorescence microscopy, we have directly observed the disruption of lipid bilayer by added ILs. Depending on the concentration, alkyl chain length, and anion hydrophobicity of ILs, the interaction of ILs with lipid bilayers leads to the formation of micelles, fibrils, and multi-lamellar vesicles for IL-lipid complexes. By MD computer simulations, we have confirmed the insertion of ILs into lipid bilayers to modify the spatial organization of lipids in the membrane. The combined experimental and simulation results correlate well with the bioassay results of IL-induced suppression in bacteria growth, thereby suggesting a possible mechanism behind the IL toxicity. National Science Foundation, Center for Research Computing at Notre Dame.

  4. Multiple bonds for the lipid interest.

    PubMed

    Kuerschner, Lars; Thiele, Christoph

    2014-08-01

    Polyene lipids and alkyne lipids allow study of lipid organization, dynamics and metabolism. Both types of lipids contain multiple bonds as the essential functional group, leading to minimal disturbance of the hydrophobic properties on which the characteristic behavior of lipids is based. Polyene lipids can directly be traced due to their intrinsic fluorescence, while alkyne lipids need the copper-catalyzed click reaction to an azido-reporter for detection. This review describes recent developments in synthesis and application of both types of lipid analogs with emphasis on metabolic tracing and microscopy imaging. This article is part of a Special Issue entitled Tools to study lipid functions. PMID:24412758

  5. Lipid-Protein-Wechselwirkungen

    NASA Astrophysics Data System (ADS)

    Sandhoff, Konrad

    1980-09-01

    Investigations of the genetic basis of ganglioside catabolism have led to the characterisation of two types of lipid-enzyme interaction: a) Breakdown of membrane-bound glycolipids as far as catalysed by membrane-bound enzymes is regulated by the membrane itself. b) The degradation of micelle-forming glycolipids by water-soluble lysosomal enzymes is facilitated by cofactors known as activator proteins. A genetic defect in an activator protein can be just as fatal as the lack of the enzyme itself.

  6. Synthesis of LipidGreen2 and its application in lipid and fatty liver imaging.

    PubMed

    Chun, Hang-Suk; Jeon, Jong Hyun; Pagire, Haushabhau S; Lee, Jae Hong; Chung, Hee-Chung; Park, Myoung Joo; So, Ju-Hoon; Ryu, Jae-Ho; Kim, Cheol-Hee; Ahn, Jin Hee; Bae, Myung Ae

    2013-04-01

    We have developed LipidGreen2, a second generation small molecule probe for lipid imaging. LipidGreen2 has a better fluorescence signal compared with the previous LipidGreen, and selectively stains neutral lipids in cells and fat deposits in live zebrafish. We also demonstrate the application of LipidGreen2 for detecting fatty liver. PMID:23412429

  7. Lipid mobility in supported lipid bilayers by single molecule tracking

    NASA Astrophysics Data System (ADS)

    Kohram, Maryam; Shi, Xiaojun; Smith, Adam

    2015-03-01

    Phospholipid bilayers are the main component of cell membranes and their interaction with biomolecules in their immediate environment is critical for cellular functions. These interactions include the binding of polycationic polymers to lipid bilayers which affects many cell membrane events. As an alternative method of studying live cell membranes, we assemble a supported lipid bilayer and investigate its binding with polycationic polymers in vitro by fluorescently labeling the molecules of the supported lipid bilayer and tracking their mobility. In this work, we use single molecule tracking total internal reflection fluorescence microscopy (TIRF) to study phosphatidylinositol phosphate (PIP) lipids with and without an adsorbed polycationic polymer, quaternized polyvinylpyridine (QPVP). Individual molecular trajectories are obtained from the experiment, and a Brownian diffusion model is used to determine diffusion coefficients through mean square displacements. Our results indicate a smaller diffusion coefficient for the supported lipid bilayers in the presence of QPVP in comparison to its absence, revealing that their binding causes a decrease in lateral mobility.

  8. Spiroplasma membrane lipids.

    PubMed Central

    Davis, P J; Katznel, A; Razin, S; Rottem, S

    1985-01-01

    Membranes of six spiroplasma strains belonging to different Spiroplasma species and subgroups were isolated by a combination of osmotic lysis and sonication in the presence of EDTA to block endogenous phospholipase activity. Analysis of membrane lipids showed that in addition to free and esterified cholesterol the spiroplasmas incorporated exogenous phospholipids from the growth medium. Sphingomyelin was preferentially incorporated from phosphatidylcholine-sphingomyelin vesicles or from the serum used to supplement the growth medium. Palmitate was incorporated better than oleate into membrane lipids synthesized by the organisms during growth. The major phospholipid synthesized by the spiroplasmas was phosphatidylglycerol. The positional distribution of the fatty acids in phosphatidylglycerol of Spiroplasma floricola resembled that found in Mycoplasma species, in which the saturated fatty acids prefer position 2 in the glycerol backbone and not position 1 as found in Acholeplasma species and elsewhere in nature. Electron paramagnetic resonance analysis of spin-labeled fatty acids incorporated into S. floricola membranes exhibited homogeneous single-component spectra without immobilized regions. The S. floricola membranes were more rigid than those of Acholeplasma laidlawii and less rigid than those of Mycoplasma gallisepticum. PMID:2981796

  9. Polar lipids from oat kernels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oat (Avena sativa L.) kernels appear to contain much higher polar lipid concentrations than other plant tissues. We have extracted, identified, and quantified polar lipids from 18 oat genotypes grown in replicated plots in three environments in order to determine genotypic or environmental variation...

  10. Neuroimaging of Lipid Storage Disorders

    ERIC Educational Resources Information Center

    Rieger, Deborah; Auerbach, Sarah; Robinson, Paul; Gropman, Andrea

    2013-01-01

    Lipid storage diseases, also known as the lipidoses, are a group of inherited metabolic disorders in which there is lipid accumulation in various cell types, including the central nervous system, because of the deficiency of a variety of enzymes. Over time, excessive storage can cause permanent cellular and tissue damage. The brain is particularly…

  11. Lipids changes in liver cancer*

    PubMed Central

    Jiang, Jing-ting; Xu, Ning; Zhang, Xiao-ying; Wu, Chang-ping

    2007-01-01

    Liver is one of the most important organs in energy metabolism. Most plasma apolipoproteins and endogenous lipids and lipoproteins are synthesized in the liver. It depends on the integrity of liver cellular function, which ensures homeostasis of lipid and lipoprotein metabolism. When liver cancer occurs, these processes are impaired and the plasma lipid and lipoprotein patterns may be changed. Liver cancer is the fifth common malignant tumor worldwide, and is closely related to the infections of hepatitis B virus (HBV) and hepatitis C virus (HCV). HBV and HCV infections are quite common in China and other Southeast Asian countries. In addition, liver cancer is often followed by a procession of chronic hepatitis or cirrhosis, so that hepatic function is damaged obviously on these bases, which may significantly influence lipid and lipoprotein metabolism in vivo. In this review we summarize the clinical significance of lipid and lipoprotein metabolism under liver cancer. PMID:17565510

  12. Crystallizing Membrane Proteins in Lipidic Mesophases. A Host Lipid Screen

    SciTech Connect

    Li, Dianfan; Lee, Jean; Caffrey, Martin

    2011-11-30

    The default lipid for the bulk of the crystallogenesis studies performed to date using the cubic mesophase method is monoolein. There is no good reason, however, why this 18-carbon, cis-monounsaturated monoacylglycerol should be the preferred lipid for all target membrane proteins. The latter come from an array of biomembrane types with varying properties that include hydrophobic thickness, intrinsic curvature, lateral pressure profile, lipid and protein makeup, and compositional asymmetry. Thus, it seems reasonable that screening for crystallizability based on the identity of the lipid creating the hosting mesophase would be worthwhile. For this, monoacylglycerols with differing acyl chain characteristics, such as length and olefinic bond position, must be available. A lipid synthesis and purification program is in place in the author's laboratory to serve this need. In the current study with the outer membrane sugar transporter, OprB, we demonstrate the utility of host lipid screening as a means for generating diffraction-quality crystals. Host lipid screening is likely to prove a generally useful strategy for mesophase-based crystallization of membrane proteins.

  13. Fat caves: caveolae, lipid trafficking and lipid metabolism in adipocytes

    PubMed Central

    Liu, Libin

    2011-01-01

    Caveolae are subdomains of the eukaryotic cell surface that are so-called because they resemble little caves, small omega-shaped invaginations of the plasma membrane into the cytosol. They are present in many cell types and are especially abundant in adipocytes where they have been implicated as playing a role in lipid metabolism. Thus mice and humans lacking caveolae have small adipocytes and exhibit lipodystrophies along with other physiological abnormalities. Here we review the evidence supporting the role of caveolae in adipocyte lipid metabolism in the context of the protein and lipid composition of these structures. PMID:21592817

  14. Lipid mediators in diabetic nephropathy

    PubMed Central

    2014-01-01

    The implications of lipid lowering drugs in the treatment of diabetic nephropathy have been considered. At the same time, the clinical efficacy of lipid lowering drugs has resulted in improvement in the cardiovascular functions of chronic kidney disease (CKD) patients with or without diabetes, but no remarkable improvement has been observed in the kidney outcome. Earlier lipid mediators have been shown to cause accumulative effects in diabetic nephropathy (DN). Here, we attempt to analyze the involvement of lipid mediators in DN. The hyperglycemia-induced overproduction of diacyglycerol (DAG) is one of the causes for the activation of protein kinase C (PKCs), which is responsible for the activation of pathways, including the production of VEGF, TGF?1, PAI-1, NADPH oxidases, and NF?B signaling, accelerating the development of DN. Additionally, current studies on the role of ceramide are one of the major fields of study in DN. Researchers have reported excessive ceramide formation in the pathobiological conditions of DN. There is less report on the effect of lipid lowering drugs on the reduction of PKC activation and ceramide synthesis. Regulating PKC activation and ceramide biosynthesis could be a protective measure in the therapeutic potential of DN. Lipid lowering drugs also upregulate anti-fibrotic microRNAs, which could hint at the effects of lipid lowering drugs in DN. PMID:25206927

  15. Lipid droplet-organelle interactions: emerging roles in lipid metabolism

    E-print Network

    Barbosa, Antonio Daniel; Savage, David B.; Siniossoglou, Symeon

    2015-05-15

    conserved dynamic organelles that can store and mobilize fatty acids and other lipid species for their multiple cellular roles. Increasing evidence suggests that contact zones between LDs and other organelles play important roles in the trafficking...

  16. Volumetric Stability of Lipid Bilayers

    PubMed Central

    Hallinen, Kelsey M.; Tristram-Nagle, Stephanie

    2012-01-01

    In agreement with recent reports, a commercial densimeter has yielded a gradual decrease in lipid molecular volume of DPPC multilamellar vesicle dispersions in the gel phase upon repeated thermal cycling between 10ºC and 50ºC. The considerable size of this decrease would have significant implications for the physical chemistry of biomembranes. In contrast, neutral buoyancy measurements performed with similar thermal cycling indicate no gradual change in lipid volume in the gel phase at 20ºC. Remixing the lipid in the densimeter shows that the apparent volume decrease is an artifact. We conclude that gel phase DPPC bilayers exist in a volumetrically stable phase. PMID:23069984

  17. Hybrid lipid-based nanostructures

    NASA Astrophysics Data System (ADS)

    Dayani, Yasaman

    Biological membranes serve several important roles, such as structural support of cells and organelles, regulation of ionic and molecular transport, barriers to non-mediated transport, contact between cells within tissues, and accommodation of membrane proteins. Membrane proteins and other vital biomolecules incorporated into the membrane need a lipid membrane to function. Due to importance of lipid bilayers and their vital function in governing many processes in the cell, the development of various models as artificial lipid membranes that can mimic cell membranes has become a subject of great interest. Using different models of artificial lipid membranes, such as liposomes, planar lipid bilayers and supported or tethered lipid bilayers, we are able to study many biophysical processes in biological membranes. The ability of different molecules to interact with and change the structure of lipid membranes can be also investigated in artificial lipid membranes. An important application of lipid bilayer-containing interfaces is characterization of novel membrane proteins for high throughput drug screening studies to investigate receptor-drug interactions and develop biosensor systems. Membrane proteins need a lipid bilayer environment to preserve their stability and functionality. Fabrication of materials that can interact with biomolecules like proteins necessitates the use of lipid bilayers as a mimic of cell membranes. The objective of this research is to develop novel hybrid lipid-based nanostructures mimicking biological membranes. Toward this aim, two hybrid biocompatible structures are introduced: lipid bilayer-coated multi-walled carbon nanotubes (MWCNTs) and hydrogel-anchored liposomes with double-stranded DNA anchors. These structures have potential applications in biosensing, drug targeting, drug delivery, and biophysical studies of cell membranes. In the first developed nanostructure, lipid molecules are covalently attached to the surfaces of MWCNTs, and then, using a sonication process, a uniform lipid bilayer that supports the incorporation of membrane proteins is formed. These bilayer-coated carbon nanotubes are highly dispersible and stable in aqueous solution, and they can be used in development of various biosensors and energy producing devices. In the other hybrid nanostructure, the lipid bilayer of a liposome is covalently anchored to a biocompatible poly(ethylene) glycol (PEG) hydrogel core using double-stranded DNA (dsDNA) linkers. Release studies shows that nano-size hydrogel-anchored liposomes are exceptionally stable, and they can be used as biomimetic model membranes that mimic the connectivity between the cytoskeleton and the plasma membrane. After lipid bilayer removal, dsDNA linkers can provide programmable nanogels decorated with oligonucleotides with potential sites for further molecular assembly. These stable nanostructures can be useful for oligonucleotide and drug delivery applications. The developed hydrogel-anchored liposomes are exploited for encapsulation and intracellular delivery of therapeutic peptide. Peptides with anti-cancer properties are successfully encapsulated in hydrogel core of pH-sensitive liposomes during rehydration process. Liposomes release their cargo at acidic pH. Confocal microscopy confirms the intracellular delivery of liposomes through an endocytotic pathway.

  18. Nanoparticle Interactions with Lipid Bilayers

    E-print Network

    Edwards, Shayson C.

    2015-01-01

    of protein cancer markers with biobarcoded nanoparticlenanoparticle is released 50 . Nanoparticles are also used for the application of proteinprotein sensing with nanopores—especially DNA sequencing, and artificial lipid bilayers have the potential be applied for use in nanoparticle

  19. Lipid dynamics at dendritic spines

    PubMed Central

    Dotti, Carlos Gerardo; Esteban, Jose Antonio; Ledesma, María Dolores

    2014-01-01

    Dynamic changes in the structure and composition of the membrane protrusions forming dendritic spines underlie memory and learning processes. In recent years a great effort has been made to characterize in detail the protein machinery that controls spine plasticity. However, we know much less about the involvement of lipids, despite being major membrane components and structure determinants. Moreover, protein complexes that regulate spine plasticity depend on specific interactions with membrane lipids for proper function and accurate intracellular signaling. In this review we gather information available on the lipid composition at dendritic spine membranes and on its dynamics. We pay particular attention to the influence that spine lipid dynamism has on glutamate receptors, which are key regulators of synaptic plasticity. PMID:25152717

  20. Electronic polymers in lipid membranes

    PubMed Central

    Johansson, Patrik K.; Jullesson, David; Elfwing, Anders; Liin, Sara I.; Musumeci, Chiara; Zeglio, Erica; Elinder, Fredrik; Solin, Niclas; Inganäs, Olle

    2015-01-01

    Electrical interfaces between biological cells and man-made electrical devices exist in many forms, but it remains a challenge to bridge the different mechanical and chemical environments of electronic conductors (metals, semiconductors) and biosystems. Here we demonstrate soft electrical interfaces, by integrating the metallic polymer PEDOT-S into lipid membranes. By preparing complexes between alkyl-ammonium salts and PEDOT-S we were able to integrate PEDOT-S into both liposomes and in lipid bilayers on solid surfaces. This is a step towards efficient electronic conduction within lipid membranes. We also demonstrate that the PEDOT-S@alkyl-ammonium:lipid hybrid structures created in this work affect ion channels in the membrane of Xenopus oocytes, which shows the possibility to access and control cell membrane structures with conductive polyelectrolytes. PMID:26059023

  1. Lipid interactions during virus entry and infection

    PubMed Central

    Mazzon, Michela; Mercer, Jason

    2014-01-01

    Summary For entry and infection viruses have developed numerous strategies to subjugate indispensable cellular factors and functions. Host cell lipids and cellular lipid synthesis machinery are no exception. Not only do viruses exploit existing lipid signalling and modifications for virus entry and trafficking, they also reprogram lipid synthesis, metabolism, and compartmentalization for assembly and egress. Here we review these various concepts and highlight recent progress in understanding viral interactions with host cell lipids during entry and assembly. PMID:25131438

  2. Lipid bilayers on nano-templates

    DOEpatents

    Noy, Aleksandr (Belmont, CA); Artyukhin, Alexander B. (Menlo Park, CA); Bakajin, Olgica (San Leandro, CA); Stoeve, Pieter (Davis, CA)

    2009-08-04

    A lipid bilayer on a nano-template comprising a nanotube or nanowire and a lipid bilayer around the nanotube or nanowire. One embodiment provides a method of fabricating a lipid bilayer on a nano-template comprising the steps of providing a nanotube or nanowire and forming a lipid bilayer around the polymer cushion. One embodiment provides a protein pore in the lipid bilayer. In one embodiment the protein pore is sensitive to specific agents

  3. The Lipids of Pneumocystis carinii

    PubMed Central

    Kaneshiro, Edna S.

    1998-01-01

    Information about a number of Pneumocystis carinii lipids obtained by the analyses of organisms isolated and purified from infected lungs of corticosteroid-immunosuppressed rats has been reported in recent years. Of the common opportunistic protists associated with AIDS (Cryptosporidium, Toxoplasma, and the microsporidia), more is currently known about the lipids of P. carinii than the others. Lipids that are synthesized by the organism but not by humans are attractive targets for drug development. Thus, the elucidation of ?7C-24-alykylated sterol and cis-9,10-epoxystearic acid biosyntheses in P. carinii is currently being examined in detail, since these have been identified as P. carinii-specific lipids. The development of low-toxicity drugs that prevent sterol C-24 alkylation and the specific inhibition of the lipoxygenase that forms cis-9,10-epoxystearic acid might prove fruitful. Although humans can synthesize coenzyme Q10, the anti-P. carinii activity and low toxicity of ubiquinone analogs such as atovaquone suggest that the electron transport chain in the pathogen may differ importantly from that in the host. Although resistance to atovaquone has been observed, development of other naphthoquinone drugs would provide a broader armamentarium of drugs to treat patients with P. carinii pneumonia. Studies of bronchoalveolar lavage fluid and of infected lungs have demonstrated that the infection causes a number of chemical abnormalities. Bronchoalveolar lavage fluid obtained after the removal of lung cellular material and the organisms has been shown to contain larger amounts of surfactant proteins and smaller amounts of phospholipids than do comparable samples from P. carinii-free lungs. Increased phospholipase activity, inhibition of surfactant secretion by type II cells, and uptake and catabolism of lipids by the pathogen may explain this phenomenon related to P. carinii pneumonia. Although not yet thoroughly examined, initial studies on the uptake and metabolism of lipids by P. carinii suggest that the organism relies heavily on exogenous lipid nutrients. PMID:9457427

  4. Mass Spectrometry Methodology in Lipid Analysis

    PubMed Central

    Li, Lin; Han, Juanjuan; Wang, Zhenpeng; Liu, Jian’an; Wei, Jinchao; Xiong, Shaoxiang; Zhao, Zhenwen

    2014-01-01

    Lipidomics is an emerging field, where the structures, functions and dynamic changes of lipids in cells, tissues or body fluids are investigated. Due to the vital roles of lipids in human physiological and pathological processes, lipidomics is attracting more and more attentions. However, because of the diversity and complexity of lipids, lipid analysis is still full of challenges. The recent development of methods for lipid extraction and analysis and the combination with bioinformatics technology greatly push forward the study of lipidomics. Among them, mass spectrometry (MS) is the most important technology for lipid analysis. In this review, the methodology based on MS for lipid analysis was introduced. It is believed that along with the rapid development of MS and its further applications to lipid analysis, more functional lipids will be identified as biomarkers and therapeutic targets and for the study of the mechanisms of disease. PMID:24921707

  5. Lipid Metabolism, Apoptosis and Cancer Therapy

    PubMed Central

    Huang, Chunfa; Freter, Carl

    2015-01-01

    Lipid metabolism is regulated by multiple signaling pathways, and generates a variety of bioactive lipid molecules. These bioactive lipid molecules known as signaling molecules, such as fatty acid, eicosanoids, diacylglycerol, phosphatidic acid, lysophophatidic acid, ceramide, sphingosine, sphingosine-1-phosphate, phosphatidylinositol-3 phosphate, and cholesterol, are involved in the activation or regulation of different signaling pathways. Lipid metabolism participates in the regulation of many cellular processes such as cell growth, proliferation, differentiation, survival, apoptosis, inflammation, motility, membrane homeostasis, chemotherapy response, and drug resistance. Bioactive lipid molecules promote apoptosis via the intrinsic pathway by modulating mitochondrial membrane permeability and activating different enzymes including caspases. In this review, we discuss recent data in the fields of lipid metabolism, lipid-mediated apoptosis, and cancer therapy. In conclusion, understanding the underlying molecular mechanism of lipid metabolism and the function of different lipid molecules could provide the basis for cancer cell death rationale, discover novel and potential targets, and develop new anticancer drugs for cancer therapy. PMID:25561239

  6. [Protein-lipid interactions during lipid peroxidation in photoreceptor membranes].

    PubMed

    Novikov, K N; Kagan, V E; Shvedova, A A; Kozlov, Iu P

    1975-01-01

    It has been shown that chemical modification of hydrophobic lipid phase (lipoperoxidation) of outer segments membrane discs of frog retina rods brings about weakening protein-lipid interactions in the photoreceptor membrane. As a result of this extraction of rhodopsin with anion detergent (sodium cholate) in the concentrations not exceeding the critical concentration of micelloformation increases, and spontaneous release of rhodopsin into water phase is observed. At the same time the number of phospholipid molecules extracted in lipoprotein rhodopsin complex from the membranes of outer segments decreases 3-4-fold. PMID:1081883

  7. It’s a lipid’s world: Bioactive lipid metabolism and signaling in neural stem cell differentiation

    PubMed Central

    Bieberich, Erhard

    2012-01-01

    Lipids are often considered membrane components whose function is to embed proteins into cell membranes. In the last two decades, studies on brain lipids have unequivocally demonstrated that many lipids have critical cell signaling functions; they are called “bioactive lipids”. Pioneering work in Dr. Robert Ledeen’s laboratory has shown that two bioactive brain sphingolipids, sphingomyelin and the ganglioside GM1 are major signaling lipids in the nuclear envelope. In addition to derivatives of the sphingolipid ceramide, the bioactive lipids discussed here belong to the classes of terpenoids and steroids, eicosanoids, and lysophospholipids. These lipids act mainly through two mechanisms: 1) direct interaction between the bioactive lipid and a specific protein binding partner such as a lipid receptor, protein kinase or phosphatase, ion exchanger, or other cell signaling protein; and 2) formation of lipid microdomains or rafts that regulate the activity of a group of raft-associated cell signaling proteins. In recent years, a third mechanism has emerged, which invokes lipid second messengers as a regulator for the energy and redox balance of differentiating neural stem cells (NSCs). Interestingly, developmental niches such as the stem cell niche for adult NSC differentiation may also be metabolic compartments that respond to a distinct combination of bioactive lipids. The biological function of these lipids as regulators of NSC differentiation will be reviewed and their application in stem cell therapy discussed. PMID:22246226

  8. Discontinuous Unbinding of Lipid Multibilayers

    NASA Astrophysics Data System (ADS)

    Pozo-Navas, B.; Raghunathan, V. A.; Katsaras, J.; Rappolt, M.; Lohner, K.; Pabst, G.

    2003-07-01

    We have observed a discontinuous unbinding transition of lipid bilayer stacks composed of phosphatidylethanolamine and phosphatidylglycerol using x-ray diffraction. The unbinding is reversible and coincides with the main (L??L?) transition of the lipid mixture. Interbilayer interaction potentials deduced from the diffraction data reveal that the bilayers in the L? phase are only weakly bound. The unbinding transition appears to be driven by an abrupt increase in steric repulsion resulting from increased thermal undulations of the bilayers upon entering the fluid L? phase.

  9. Extraction of lipids from yeast.

    PubMed

    Sobus, M T; Homlund, C E

    1976-04-01

    Several methods for the extraction of lipids from intact yeast cells have been compared. Extraction of intact cells with methanol followed by methanol: benzene (1:1, v/v) and benzene resulted in the recovery of equal or greater amounts of polar and nonpolar lipids than obtained by other methods. A preparative method involving preincubation of cells with aqueous KOH followed by the treatment of the cellular residue as described above yielded slightly more steryl esters than was extracted from broken cell preparations. PMID:772348

  10. Secondary structure of lipidated Ras bound to a lipid bilayer

    E-print Network

    Gerwert, Klaus

    , Dortmund, Germany Ras proteins are molecular switches [1] that operate in distinct cellular activities.1111/j.1742-4658.2008.06720.x Ras proteins are small guanine nucleotide binding proteins that regulate of Ras proteins. Here, for the first time, attenuated total reflectance-FTIR studies of lipid

  11. The Membrane and Lipids as Integral Participants in Signal Transduction: Lipid Signal Transduction for the Non-Lipid Biochemist

    ERIC Educational Resources Information Center

    Eyster, Kathleen M.

    2007-01-01

    Reviews of signal transduction have often focused on the cascades of protein kinases and protein phosphatases and their cytoplasmic substrates that become activated in response to extracellular signals. Lipids, lipid kinases, and lipid phosphatases have not received the same amount of attention as proteins in studies of signal transduction.…

  12. Model Protocells from Single-Chain Lipids

    PubMed Central

    Mansy, Sheref S.

    2009-01-01

    Significant progress has been made in the construction of laboratory models of protocells. Most frequently the developed vesicle systems utilize single-chain lipids rather than the double-chain lipids typically found in biological membranes. Although single-chain lipids yield less robust vesicles, their dynamic characteristics are highly exploitable for protocellular functions. Herein the advantages of using single-chain lipids in the construction of protocells are discussed. PMID:19399223

  13. Evolution of lipid management guidelines

    PubMed Central

    John Bosomworth, N.

    2014-01-01

    Abstract Objective To understand how the new guidelines for management of cardiovascular risk by the American Heart Association and the American College of Cardiology (AHA-ACC) can be interpreted and used in a Canadian setting. Sources of information The AHA-ACC guidelines were reviewed, along with all references. Independent PubMed searches were done to include the addition of other lipid-lowering therapy to statins and the use of medical calculators to enhance patient understanding. Main message The new AHA-ACC guidelines are based on the best current evidence related to lipid management. This includes use of 10-year cardiovascular disease (CVD) risk as the treatment threshold in place of low-density lipoprotein cholesterol levels, as well as abandonment of low-density lipoprotein treatment targets. There is increased emphasis on dietary and exercise interventions, with the beginning of an effort to quantify the effect of these interventions. Statins are the main drug intervention, and the addition of other drugs to augment lipid lowering is no longer recommended. For application in Canada, Framingham risk tables are more appropriate for risk assessment than the pooled cohort equations used in the United States. Risk calculators for CVD risk should contain information on cardiovascular age and have the ability to represent risk and alternative interventions graphically in order to improve patient understanding and promote informed decision making. Conclusion Focus on the best evidence in CVD risk can simplify lipid management for both the physician and the patient. PMID:25022632

  14. You Sank My Lipid Rafts!

    ERIC Educational Resources Information Center

    Campbell, Tessa N.

    2009-01-01

    The plasma membrane is the membrane that serves as a boundary between the interior of a cell and its extracellular environment. Lipid rafts are microdomains within a cellular membrane that possess decreased fluidity due to the presence of cholesterol, glycolipids, and phospholipids containing longer fatty acids. These domains are involved in many…

  15. THE RESIDUAL LIPIDS OF FISH PROTEIN CONCENTRATES

    E-print Network

    THE RESIDUAL LIPIDS OF FISH PROTEIN CONCENTRATES Previous papers (Medwadowski, Van der Veen, and Olcott, 1967,1968; Medwadowski et a1., 1971), presented data on the residual lipids in fish pro- tein on the lipids. After 6 mo at 37° or 50°C, there were decreases in the contents of highly unsaturated fatty acids

  16. Plant lipid binding proteins: properties and applications.

    PubMed

    Marion, Didier; Bakan, Bénédicte; Elmorjani, Khalil

    2007-01-01

    Lipid transfer proteins (LTP) and puroindolines are abundant lipid binding proteins of plant seeds. While LTP are ubiquitous plant proteins, puroindolines are only found in the seeds of plants from the Triticae and Avenae tribes. These proteins display a similar overall folding pattern but different lipid binding properties. The unique and diverse biological and technological functions of LTPs and puroindolines are closely related to their structural and lipid binding properties. These proteins are attractive to improve the agronomic performances and food quality of crops. Heterologous expression and genetic engineering should allow industrial production and enlarge applications of these lipid binding proteins. PMID:17196784

  17. Polymer lipids stabilize the ripple phase in lipid bilayers

    NASA Astrophysics Data System (ADS)

    Cunningham, Beth; Likar, Justin; Wolfe, David; Williams, W. Patrick

    2001-03-01

    We have recently discovered using X-ray diffraction that incorporating membrane lipids with covalently attached polymer headgroups leads to a marked stabilization of the ripple phase of dipalmitoyl phosphatidylcholine (DPPC). The ripple phase of DPPC is an undulated gel phase normally restricted to a temperature range 36 to 41^oC. In the presence of small amounts of dipalmitoyl phosphatidylethanolamine (DPPE) derivatives with polyethylene glycol (PEG) headgroups, the ripple phase is stable over a temperature range of a least 20 to 65^oC. We attribute this ability of the polymer lipid to stabilize the ripple phase to its tendency to accumulate in, and then stabilize, regions of high membrane curvature^1. 1. H.E. Warriner, P. Davidson, N.L. Slack, M. Schellhorn, P. Eiselt, S. H. J. Idziak, H.-W. Schmidt, and C.R. Safinya, J. Chem. Phys. (1997) 107, 3707-3722.

  18. Emerging targets in lipid-based therapy?

    PubMed Central

    Tucker, Stephanie C.; Honn, Kenneth V.

    2013-01-01

    The use of prostaglandins and NSAIDS in the clinic has proven that lipid mediators and their associated pathways make attractive therapeutic targets. When contemplating therapies involving lipid pathways, several basic agents come to mind. There are the enzymes and accessory proteins that lead to the metabolism of lipid substrates, provided through diet or through actions of lipases, the subsequent lipid products, and finally the lipid sensors or receptors. There is abundant evidence that molecules along this lipid continuum can serve as prognostic and diagnostic indicators and are in fact viable therapeutic targets. Furthermore, lipids themselves can be used as therapeutics. Despite this, the vernacular dialog pertaining to “biomarkers” does not routinely include mention of lipids, though this is rapidly changing. Collectively these agents are becoming more appreciated for their respective roles in diverse disease processes from cancer to preterm labor and are receiving their due appreciation after decades of ground work in the lipid field. By relating examples of disease processes that result from dysfunction along the lipid continuum, as well as examples of lipid therapies and emerging technologies, this review is meant to inspire further reading and discovery. PMID:23261527

  19. Condensed DNA in lipid microcompartments.

    PubMed

    Osfouri, Shahriar; Stano, Pasquale; Luisi, Pier Luigi

    2005-10-27

    DNA was studied in lipid reverse micelles with the aim of investigating the interactions of DNA with lipids in a restricted compartment with minimal water content. Circular dichroic (CD) spectra of DNA at low water content showed the characteristic polymer-salt-induced (psi) spectra of condensed DNA. Dynamic light scattering showed a peak around a radius of 400 nm (corresponding to DNA-containing micelles), and a peak around 2.5 nm (corresponding to "empty" micelles). Fourier Transform-IR (FT-IR) spectroscopy was carried out and analyzed in terms of three distinct states of water inside the micelle water pool, where the local concentration of DNA reached an estimated value of ca. 600 mg/mL, comparable to that found in restricted biological compartments. PMID:16853577

  20. Lipid Chaperones and Metabolic Inflammation

    PubMed Central

    Furuhashi, Masato; Ishimura, Shutaro; Ota, Hideki; Miura, Tetsuji

    2011-01-01

    Over the past decade, a large body of evidence has emerged demonstrating an integration of metabolic and immune response pathways. It is now clear that obesity and associated disorders such as insulin resistance and type 2 diabetes are associated with a metabolically driven, low-grade, chronic inflammatory state, referred to as “metaflammation.” Several inflammatory cytokines as well as lipids and metabolic stress pathways can activate metaflammation, which targets metabolically critical organs and tissues including adipocytes and macrophages to adversely affect systemic homeostasis. On the other hand, inside the cell, fatty acid-binding proteins (FABPs), a family of lipid chaperones, as well as endoplasmic reticulum (ER) stress, and reactive oxygen species derived from mitochondria play significant roles in promotion of metabolically triggered inflammation. Here, we discuss the molecular and cellular basis of the roles of FABPs, especially FABP4 and FABP5, in metaflammation and related diseases including obesity, diabetes, and atherosclerosis. PMID:22121495

  1. Lipid Bodies in Inflammatory Cells

    PubMed Central

    Melo, Rossana C. N.; D’Avila, Heloisa; Wan, Hsiao-Ching; Bozza, Patrícia T.; Dvorak, Ann M.; Weller, Peter F.

    2011-01-01

    Lipid bodies (LBs), also known as lipid droplets, have increasingly been recognized as functionally active organelles linked to diverse biological functions and human diseases. These organelles are actively formed in vivo within cells from the immune system, such as macrophages, neutrophils, and eosinophils, in response to different inflammatory conditions and are sites for synthesis and storage of inflammatory mediators. In this review, the authors discuss structural and functional aspects of LBs and current imaging techniques to visualize these organelles in cells engaged in inflammatory processes, including infectious diseases. The dynamic morphological aspects of LBs in leukocytes as inducible, newly formable organelles, elicitable in response to stimuli that lead to cellular activation, contribute to the evolving understanding of LBs as organelles that are critical regulators of different inflammatory diseases, key markers of leukocyte activation, and attractive targets for novel anti-inflammatory therapies. PMID:21430261

  2. Dietary fibre and blood lipids.

    PubMed

    Truswell, A S

    1995-02-01

    Sources of dietary fibre can be divided into three groups according to their effect on plasma lipids in humans: (1) a cholesterol-lowering effect demonstrated repeatedly by pectin, guar gum, psyllium and oat bran (sources of soluble fibre); (2) a possible, but not adequate, cholesterol-lowering effect by legumes, barley, rice bran and several types of gum; and (3) those sources that do not lower plasma cholesterol, such as wheat fibre, cellulose and lignin. PMID:7735708

  3. Pore formation phase diagrams for lipid membranes

    NASA Astrophysics Data System (ADS)

    Mukhin, S. I.; Kheyfets, B. B.

    2014-05-01

    Critical lateral pressure for a pore formation and phase diagram of porous membrane are derived analytically as functions of the microscopic parameters of the lipid chains. The derivation exploits path-integral calculation of the free energy of the ensembles of semi-flexible strings and rigid rods that mimic the hydrophobic tails of lipids in the lipid bilayers and bolalipid membranes respectively. Analytical expressions for the area stretch/compressibility moduli of the membranes are derived in both models.

  4. Polar lipid composition of a new halobacterium

    NASA Technical Reports Server (NTRS)

    Tindall, B. J.; Tomlinson, G. A.; Hochstein, L. I.

    1987-01-01

    Investigations of the polar lipid composition of a new aerobic, extremely halophilic aracheabacterium capable of nitrate reduction have shown that this organism contains two previously unknown phospholycolipids derived from diphytanyl glycerol diethers. Comparison of the lipid pattern from this new isolate with other known strains indicate that this organism is novel. On the basis of the unique polar lipid pattern it can be concluded that this organism represents a new taxon, at least at the species level.

  5. Atypical plasma lipid profiles in leukemia.

    PubMed

    Iqbal, Areeb; Zaid, Muhammad; Munir, Rimsha; Usman, Hina; Kalbacher, Hubert; Scandiuzzi, Lisa; Zaidi, Nousheen

    2016-01-15

    Numerous studies have reported alterations in the plasma lipid profiles of leukemia patients. However, there are several inconsistencies in these reports. The present review highlights and compiles findings from different research groups regarding association of plasma lipoprotein levels with the risk of developing leukemia. We have also discussed the clinical significance of plasma lipid profiles in management of leukemia. Furthermore, the potential role of plasma lipids in promoting leukemogenesis is also highlighted. PMID:26549657

  6. SEASONAL VARIABILTIY LIPIDS, LIPID CLASSES AND PCBS IN INDIGENOUS POPULATIONS OF RIBBED MUSSELS, MODIOLUS DEMISSUS

    EPA Science Inventory

    Two indigenous ribbed mussel (Modiolus demissus) populations were sampled approximately every four weeks during 1997 to investigate the seasonal variability of total lipids, lipid classes, and polychlorinated biphenyl (PCB) concentrations. One population was located in a highly c...

  7. 21 CFR 862.1470 - Lipid (total) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Lipid (total) test system. 862.1470 Section 862....1470 Lipid (total) test system. (a) Identification. A lipid (total) test system is a device intended to measure total lipids (fats or fat-like substances) in serum and plasma. Lipid (total) measurements...

  8. Dictyostelium Lipid Droplets Host Novel Proteins

    PubMed Central

    Du, Xiaoli; Barisch, Caroline; Paschke, Peggy; Herrfurth, Cornelia; Bertinetti, Oliver; Pawolleck, Nadine; Otto, Heike; Rühling, Harald; Feussner, Ivo; Herberg, Friedrich W.

    2013-01-01

    Across all kingdoms of life, cells store energy in a specialized organelle, the lipid droplet. In general, it consists of a hydrophobic core of triglycerides and steryl esters surrounded by only one leaflet derived from the endoplasmic reticulum membrane to which a specific set of proteins is bound. We have chosen the unicellular organism Dictyostelium discoideum to establish kinetics of lipid droplet formation and degradation and to further identify the lipid constituents and proteins of lipid droplets. Here, we show that the lipid composition is similar to what is found in mammalian lipid droplets. In addition, phospholipids preferentially consist of mainly saturated fatty acids, whereas neutral lipids are enriched in unsaturated fatty acids. Among the novel protein components are LdpA, a protein specific to Dictyostelium, and Net4, which has strong homologies to mammalian DUF829/Tmem53/NET4 that was previously only known as a constituent of the mammalian nuclear envelope. The proteins analyzed so far appear to move from the endoplasmic reticulum to the lipid droplets, supporting the concept that lipid droplets are formed on this membrane. PMID:24036346

  9. Dictyostelium lipid droplets host novel proteins.

    PubMed

    Du, Xiaoli; Barisch, Caroline; Paschke, Peggy; Herrfurth, Cornelia; Bertinetti, Oliver; Pawolleck, Nadine; Otto, Heike; Rühling, Harald; Feussner, Ivo; Herberg, Friedrich W; Maniak, Markus

    2013-11-01

    Across all kingdoms of life, cells store energy in a specialized organelle, the lipid droplet. In general, it consists of a hydrophobic core of triglycerides and steryl esters surrounded by only one leaflet derived from the endoplasmic reticulum membrane to which a specific set of proteins is bound. We have chosen the unicellular organism Dictyostelium discoideum to establish kinetics of lipid droplet formation and degradation and to further identify the lipid constituents and proteins of lipid droplets. Here, we show that the lipid composition is similar to what is found in mammalian lipid droplets. In addition, phospholipids preferentially consist of mainly saturated fatty acids, whereas neutral lipids are enriched in unsaturated fatty acids. Among the novel protein components are LdpA, a protein specific to Dictyostelium, and Net4, which has strong homologies to mammalian DUF829/Tmem53/NET4 that was previously only known as a constituent of the mammalian nuclear envelope. The proteins analyzed so far appear to move from the endoplasmic reticulum to the lipid droplets, supporting the concept that lipid droplets are formed on this membrane. PMID:24036346

  10. Lipid Nanoparticles for Ocular Gene Delivery

    PubMed Central

    Wang, Yuhong; Rajala, Ammaji; Rajala, Raju V. S.

    2015-01-01

    Lipids contain hydrocarbons and are the building blocks of cells. Lipids can naturally form themselves into nano-films and nano-structures, micelles, reverse micelles, and liposomes. Micelles or reverse micelles are monolayer structures, whereas liposomes are bilayer structures. Liposomes have been recognized as carriers for drug delivery. Solid lipid nanoparticles and lipoplex (liposome-polycation-DNA complex), also called lipid nanoparticles, are currently used to deliver drugs and genes to ocular tissues. A solid lipid nanoparticle (SLN) is typically spherical, and possesses a solid lipid core matrix that can solubilize lipophilic molecules. The lipid nanoparticle, called the liposome protamine/DNA lipoplex (LPD), is electrostatically assembled from cationic liposomes and an anionic protamine-DNA complex. The LPD nanoparticles contain a highly condensed DNA core surrounded by lipid bilayers. SLNs are extensively used to deliver drugs to the cornea. LPD nanoparticles are used to target the retina. Age-related macular degeneration, retinitis pigmentosa, and diabetic retinopathy are the most common retinal diseases in humans. There have also been promising results achieved recently with LPD nanoparticles to deliver functional genes and micro RNA to treat retinal diseases. Here, we review recent advances in ocular drug and gene delivery employing lipid nanoparticles. PMID:26062170

  11. Lipid transport in cholecystokinin knockout mice.

    PubMed

    King, Alexandra; Yang, Qing; Huesman, Sarah; Rider, Therese; Lo, Chunmin C

    2015-11-01

    Cholecystokinin (CCK) is released in response to lipid feeding and regulates pancreatic digestive enzymes vital to the absorption of nutrients. Our previous reports demonstrated that cholecystokinin knockout (CCK-KO) mice fed for 10 weeks of HFD had reduced body fat mass, but comparable glucose uptake by white adipose tissues and skeletal muscles. We hypothesized that CCK is involved in energy homeostasis and lipid transport from the small intestine to tissues in response to acute treatment with dietary lipids. CCK-KO mice with comparable fat absorption had increased energy expenditure and were resistant to HFD-induced obesity. Using intraduodenal infusion of butter fat and intravenous infusion using Liposyn III, we determined the mechanism of lipid transport from the small intestine to deposition in lymph and adipocytes in CCK-KO mice. CCK-KO mice had delayed secretion of Apo B48-chylomicrons, lipid transport to the lymphatic system, and triglyceride (TG)-derived fatty acid uptake by epididymal fat in response to acute treatment of intraduodenal lipids. In contrast, CCK-KO mice had comparable TG clearance and lipid uptake by white adipocytes in response to TGs in chylomicron-like emulsion. Thus, we concluded that CCK is important for lipid transport and energy expenditure to control body weight in response to dietary lipid feeding. PMID:26171590

  12. Zebrafish: gaining popularity in lipid research.

    PubMed

    Hölttä-Vuori, Maarit; Salo, Veijo T V; Nyberg, Lena; Brackmann, Christian; Enejder, Annika; Panula, Pertti; Ikonen, Elina

    2010-07-15

    Zebrafish are an increasingly popular vertebrate model organism in which to study biological phenomena. It has been widely used, especially in developmental biology and neurobiology, and many aspects of its development and physiology are similar to those of mammals. The popularity of zebrafish relies on its relatively low cost, rapid development and ease of genetic manipulation. Moreover, the optical transparency of the developing fish together with novel imaging techniques enable the direct visualization of complex phenomena at the level of the entire organism. This potential is now also being increasingly appreciated by the lipid research community. In the present review we summarize basic information on the lipid composition and distribution in zebrafish tissues, including lipoprotein metabolism, intestinal lipid absorption, the yolk lipids and their mobilization, as well as lipids in the nervous system. We also discuss studies in which zebrafish have been employed for the visualization of whole-body lipid distribution and trafficking. Finally, recent advances in using zebrafish as a model for lipid-related diseases, including atherosclerosis, obesity, diabetes and hepatic steatosis are highlighted. As the insights into zebrafish lipid metabolism increase, it is likely that zebrafish as a model organism will become an increasingly powerful tool in lipid research. PMID:20578994

  13. Supported Lipid Bilayer/Carbon Nanotube Hybrids

    NASA Astrophysics Data System (ADS)

    Zhou, Xinjian; Moran-Mirabal, Jose; Craighead, Harold; McEuen, Paul

    2007-03-01

    We form supported lipid bilayers on single-walled carbon nanotubes and use this hybrid structure to probe the properties of lipid membranes and their functional constituents. We first demonstrate membrane continuity and lipid diffusion over the nanotube. A membrane-bound tetanus toxin protein, on the other hand, sees the nanotube as a diffusion barrier whose strength depends on the diameter of the nanotube. Finally, we present results on the electrical detection of specific binding of streptavidin to biotinylated lipids with nanotube field effect transistors. Possible techniques to extract dynamic information about the protein binding events will also be discussed.

  14. Cholesterol Perturbs Lipid Bilayers Nonuniversally

    SciTech Connect

    Pan Jianjun; Mills, Thalia T.; Tristram-Nagle, Stephanie; Nagle, John F.

    2008-05-16

    Cholesterol is well known to modulate the physical properties of biomembranes. Using modern x-ray scattering methods, we have studied the effects of cholesterol on the bending modulus K{sub C}, the thickness D{sub HH}, and the orientational order parameter S{sub xray} of lipid bilayers. We find that the effects are different for at least three classes of phospholipids characterized by different numbers of saturated hydrocarbon chains. Most strikingly, cholesterol strongly increases K{sub C} when both chains of the phospholipid are fully saturated but not at all when there are two monounsaturated chains.

  15. Phosphoinositides alter lipid bilayer properties

    PubMed Central

    Hobart, E. Ashley; Koeppe, Roger E.; Andersen, Olaf S.

    2013-01-01

    Phosphatidylinositol-4,5-bisphosphate (PIP2), which constitutes ?1% of the plasma membrane phospholipid, plays a key role in membrane-delimited signaling. PIP2 regulates structurally and functionally diverse membrane proteins, including voltage- and ligand-gated ion channels, inwardly rectifying ion channels, transporters, and receptors. In some cases, the regulation is known to involve specific lipid–protein interactions, but the mechanisms by which PIP2 regulates many of its various targets remain to be fully elucidated. Because many PIP2 targets are membrane-spanning proteins, we explored whether the phosphoinositides might alter bilayer physical properties such as curvature and elasticity, which would alter the equilibrium between membrane protein conformational states—and thereby protein function. Taking advantage of the gramicidin A (gA) channels’ sensitivity to changes in lipid bilayer properties, we used gA-based fluorescence quenching and single-channel assays to examine the effects of long-chain PIP2s (brain PIP2, which is predominantly 1-stearyl-2-arachidonyl-PIP2, and dioleoyl-PIP2) on bilayer properties. When premixed with dioleoyl-phosphocholine at 2 mol %, both long-chain PIP2s produced similar changes in gA channel function (bilayer properties); when applied through the aqueous solution, however, brain PIP2 was a more potent modifier than dioleoyl-PIP2. Given the widespread use of short-chain dioctanoyl-phosphoinositides, we also examined the effects of diC8-phosphoinositol (PI), PI(4,5)P2, PI(3,5)P2, PI(3,4)P2, and PI(3,4,5)P3. The diC8 phosphoinositides, except for PI(3,5)P2, altered bilayer properties with potencies that decreased with increasing head group charge. Nonphosphoinositide diC8 phospholipids generally were more potent bilayer modifiers than the polyphosphoinositides. These results show that physiological increases or decreases in plasma membrane PIP2 levels, as a result of activation of PI kinases or phosphatases, are likely to alter lipid bilayer properties, in addition to any other effects they may have. The results further show that exogenous PIP2, as well as structural analogues that differ in acyl chain length or phosphorylation state, alters lipid bilayer properties at the concentrations used in many cell physiological experiments. PMID:23712549

  16. Phosphoinositides alter lipid bilayer properties.

    PubMed

    Rusinova, Radda; Hobart, E Ashley; Koeppe, Roger E; Andersen, Olaf S

    2013-06-01

    Phosphatidylinositol-4,5-bisphosphate (PIP2), which constitutes ?1% of the plasma membrane phospholipid, plays a key role in membrane-delimited signaling. PIP2 regulates structurally and functionally diverse membrane proteins, including voltage- and ligand-gated ion channels, inwardly rectifying ion channels, transporters, and receptors. In some cases, the regulation is known to involve specific lipid-protein interactions, but the mechanisms by which PIP2 regulates many of its various targets remain to be fully elucidated. Because many PIP2 targets are membrane-spanning proteins, we explored whether the phosphoinositides might alter bilayer physical properties such as curvature and elasticity, which would alter the equilibrium between membrane protein conformational states-and thereby protein function. Taking advantage of the gramicidin A (gA) channels' sensitivity to changes in lipid bilayer properties, we used gA-based fluorescence quenching and single-channel assays to examine the effects of long-chain PIP2s (brain PIP2, which is predominantly 1-stearyl-2-arachidonyl-PIP2, and dioleoyl-PIP2) on bilayer properties. When premixed with dioleoyl-phosphocholine at 2 mol %, both long-chain PIP2s produced similar changes in gA channel function (bilayer properties); when applied through the aqueous solution, however, brain PIP2 was a more potent modifier than dioleoyl-PIP2. Given the widespread use of short-chain dioctanoyl-phosphoinositides, we also examined the effects of diC8-phosphoinositol (PI), PI(4,5)P2, PI(3,5)P2, PI(3,4)P2, and PI(3,4,5)P3. The diC8 phosphoinositides, except for PI(3,5)P2, altered bilayer properties with potencies that decreased with increasing head group charge. Nonphosphoinositide diC8 phospholipids generally were more potent bilayer modifiers than the polyphosphoinositides. These results show that physiological increases or decreases in plasma membrane PIP2 levels, as a result of activation of PI kinases or phosphatases, are likely to alter lipid bilayer properties, in addition to any other effects they may have. The results further show that exogenous PIP2, as well as structural analogues that differ in acyl chain length or phosphorylation state, alters lipid bilayer properties at the concentrations used in many cell physiological experiments. PMID:23712549

  17. Effects of Lipid-Analog Detergent Solubilization on the Functionality and Lipidic Cubic Phase Mobility

    E-print Network

    Lasalde Dominicc, Jose A. - Department of Biology, Universidad de Puerto Rico

    Effects of Lipid-Analog Detergent Solubilization on the Functionality and Lipidic Cubic Phase studied membrane protein systems. However, the effects of detergent solubilization on nAChR stability and function are poorly understood. The use of lipid-analog detergents for nAChR solubiliza- tion has been

  18. DIRECT DETERMINATION OF THE LIPID CONTENT IN STARCH-LIPID COMPOSITES BY TIME-DOMAIN NMR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-lipid composites, prepared by excess steam jet-cooking aqueous mixtures of starch and lipid, are used in various applications for which their performance can depend upon accurate quantitation of lipid contained within these composites. A rapid and non-destructive method based on time-domain ...

  19. Chemistry and Physics of Lipids 143 (2006) 110 Partial molecular volumes of lipids and cholesterol

    E-print Network

    Nagle, John F.

    2006-01-01

    Chemistry and Physics of Lipids 143 (2006) 1­10 Partial molecular volumes of lipids and cholesterol Available online 28 April 2006 Abstract Volumetric measurements are reported for fully hydrated lipid/cholesterol for mole fractions of cholesterol x from 0 to 0.5. Unlike previous cholesterol mixture studies, we

  20. Interactions in lipid stabilised foam films.

    PubMed

    Toca-Herrera, José Luis; Krasteva, Nadejda; Müller, Hans-Joachim; Krastev, Rumen

    2014-05-01

    The interaction between lipid bilayers in water has been intensively studied over the last decades. Osmotic stress was applied to evaluate the forces between two approaching lipid bilayers in aqueous solution. The force-distance relation between lipid mono- or bilayers deposited on mica sheets using a surface force apparatus (SFA) was also measured. Lipid stabilised foam films offer another possibility to study the interactions between lipid monolayers. These films can be prepared comparatively easy with very good reproducibility. Foam films consist usually of two adsorbed surfactant monolayers separated by a layer of the aqueous solution from which the film is created. Their thickness can be conveniently measured using microinterferometric techniques. Studies with foam films deliver valuable information on the interactions between lipid membranes and especially their stability and permeability. Presenting inverse black lipid membrane (BLM) foam films supply information about the properties of the lipid self-organisation in bilayers. The present paper summarises results on microscopic lipid stabilised foam films by measuring their thickness and contact angle. Most of the presented results concern foam films prepared from dispersions of the zwitterionic lipid 1,2-dimyristoyl-sn-glycero-3-phosphorylcholine (DMPC) and some of its mixtures with the anionic lipid -- 1,2-dimyristoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DMPG). The strength of the long range and short range forces between the lipid layers is discussed. The van der Waals attractive force is calculated. The electrostatic repulsive force is estimated from experiments at different electrolyte concentrations (NaCl, CaCl?) or by modification of the electrostatic double layer surface potential by incorporating charged lipids in the lipid monolayers. The short range interactions are studied and modified by using small carbohydrates (fructose and sucrose), ethanol (EtOH) or dimethylsulfoxide (DMSO). Some results are compared with the structure of lipid monolayers deposited at the liquid/air interface (monolayers spread in Langmuir trough), which are one of most studied biomembrane model system. The comparison between the film thickness and the free energy of film formation is used to estimate the contribution of the different components of the disjoining pressure to the total interaction in the film and their dependence on the composition of the film forming solution. PMID:24641908

  1. DMSO induces dehydration near lipid membrane surfaces.

    PubMed

    Cheng, Chi-Yuan; Song, Jinsuk; Pas, Jolien; Meijer, Lenny H H; Han, Songi

    2015-07-21

    Dimethyl sulfoxide (DMSO) has been broadly used in biology as a cosolvent, a cryoprotectant, and an enhancer of membrane permeability, leading to the general assumption that DMSO-induced structural changes in cell membranes and their hydration water play important functional roles. Although the effects of DMSO on the membrane structure and the headgroup dehydration have been extensively studied, the mechanism by which DMSO invokes its effect on lipid membranes and the direct role of water in this process are unresolved. By directly probing the translational water diffusivity near unconfined lipid vesicle surfaces, the lipid headgroup mobility, and the repeat distances in multilamellar vesicles, we found that DMSO exclusively weakens the surface water network near the lipid membrane at a bulk DMSO mole fraction (XDMSO) of <0.1, regardless of the lipid composition and the lipid phase. Specifically, DMSO was found to effectively destabilize the hydration water structure at the lipid membrane surface at XDMSO <0.1, lower the energetic barrier to dehydrate this surface water, whose displacement otherwise requires a higher activation energy, consequently yielding compressed interbilayer distances in multilamellar vesicles at equilibrium with unaltered bilayer thicknesses. At XDMSO >0.1, DMSO enters the lipid interface and restricts the lipid headgroup motion. We postulate that DMSO acts as an efficient cryoprotectant even at low concentrations by exclusively disrupting the water network near the lipid membrane surface, weakening the cohesion between water and adhesion of water to the lipid headgroups, and so mitigating the stress induced by the volume change of water during freeze-thaw. PMID:26200868

  2. Donkey's milk detailed lipid composition.

    PubMed

    Gastaldi, Daniela; Bertino, Enrico; Monti, Giovanna; Baro, Cristina; Fabris, Claudio; Lezo, Antonela; Medana, Claudio; Baiocchi, Claudio; Mussap, Michele; Galvano, Fabio; Conti, Amedeo

    2010-01-01

    Donkey's milk (DM) has recently aroused scientific interest, above all among paediatric allergologists. A deeper knowledge of both proteins and fats in donkey's milk is necessary to evaluate the immunological, physiological and nutritional properties. By using the most refined techniques for fatty acids analysis, the paper offers a detailed comparative analysis of the lipid fractions of DM as well as of human and cow milk, also indicating the distribution of fatty-acid moieties among sn-1/3 and sn-2 positions of the glycerol backbone. In DM the position of fatty acids on glycerol backbone, above all of long chain saturated fatty acids, is very similar to that of human milk: this fact, in conjunction with the relatively high contents of medium-chain triglycerides, makes the lipids in DM, through quantitatively reduced, highly bioavailable. The high PUFA n-3 content of donkey's milk, and especially its low n-6/n-3 ratio, acquires particular interest in subjects affected by cow's milk protein allergy. Whole DM might also constitute the basis for formulas suitable for subjects in the first year of life. PMID:20036900

  3. Blebs in Model Lipid Membranes

    NASA Astrophysics Data System (ADS)

    Laradji, M.; Harvey, C. W.; Spangler, E. J.; Kumar, P. B. Sunil

    2009-03-01

    It is now widely recognized that biomembranes exhibit complex lateral heterogeneities. Among these are blebs, which are localized balloon-like membrane protrusions observed during cell apoptosis, necrosis, and cytokinesis. Despite the poorly understood mechanism of bleb formation and their physiological role, they recently received a renewed attention. In order to investigate the physical mechanism leading to bleb formation, we developed a model based on an implicit-solvent lipid membrane model with soft interactions recently proposed by us [J. Chem. Phys. 128, 035102 (2008)]. The model also incorporates an explicit fluctuating polymer meshwork simulating a cytoskeleton, which is anchored to the membrane. Using systematic large-scale simulations of membranes with varying values of the lipid density, cytoskeleton grafting-sites density and cytoskeleton tension, we found that localized blebs are formed on the membrane exoplasmic side in the presence of mismatch between tensions of the bare membrane and cytoskeleton. The blebs are pinned by the cytoskeleton anchors, reminiscent to those observed in apoptotic cells. The distance between neighboring anchors determines the neck of a bleb. The remaining membrane surrounding the blebs stiffens to accommodate the tensed cytoskeleton.

  4. Electrostatics of Deformable Lipid Membranes

    PubMed Central

    Vorobyov, Igor; Bekker, Borislava; Allen, Toby W.

    2010-01-01

    Abstract It was recently demonstrated that significant local deformations of biological membranes take place due to the fields of charged peptides and ions, challenging the standard model of membrane electrostatics. The ability of ions to retain their immediate hydration environment, combined with the lack of sensitivity of permeability to ion type or even ion pairs, led us to question the extent to which hydration energetics and electrostatics control membrane ion permeation. Using the arginine analog methyl-guanidinium as a test case, we find that although hydrocarbon electronic polarizability causes dramatic changes in ion solvation free energy, as well as a significant change (?0.4 V) in the membrane dipole potential, little change in membrane permeation energetics occurs. We attribute this to compensation of solvation terms from polar and polarizable nonpolar components within the membrane, and explain why the dipole potential is not fully sensed in terms of the locally deformed bilayer interface. Our descriptions provide a deeper understanding of the translocation process and allow predictions for poly-ions, ion pairs, charged lipids, and lipid flip-flop. We also report simulations of large hydrophobic-ion-like membrane defects and the ionophore valinomycin, which exhibit little membrane deformation, as well as hydrophilic defects and the ion channel gramicidin A, to provide parallels to membranes deformed by unassisted ion permeation. PMID:20550903

  5. 2011 Plant Lipids: Structure, Metabolism, & Function Gordon Research Conference

    SciTech Connect

    Christopher Benning

    2011-02-04

    This is the second Gordon Research Conference on 'Plant Lipids: Structure, Metabolism & Function'. It covers current topics in lipid structure, metabolism and function in eukaryotic photosynthetic organisms including seed plants, algae, mosses and ferns. Work in photosynthetic bacteria is considered as well as it serves the understanding of specific aspects of lipid metabolism in plants. Breakthroughs are discussed in research on plant lipids as diverse as glycerolipids, sphingolipids, lipids of the cell surface, isoprenoids, fatty acids and their derivatives. The program covers nine concepts at the forefront of research under which afore mentioned plant lipid classes are discussed. The goal is to integrate areas such as lipid signaling, basic lipid metabolism, membrane function, lipid analysis, and lipid engineering to achieve a high level of stimulating interaction among diverse researchers with interests in plant lipids. One Emphasis is on the dynamics and regulation of lipid metabolism during plant cell development and in response to environmental factors.

  6. Method of fabricating lipid bilayer membranes on solid supports

    NASA Technical Reports Server (NTRS)

    Cho, Nam-Joon (Inventor); Frank, Curtis W. (Inventor); Glenn, Jeffrey S. (Inventor); Cheong, Kwang Ho (Inventor)

    2012-01-01

    The present invention provides a method of producing a planar lipid bilayer on a solid support. With this method, a solution of lipid vesicles is first deposited on the solid support. Next, the lipid vesicles are destabilized by adding an amphipathic peptide solution to the lipid vesicle solution. This destabilization leads to production of a planar lipid bilayer on the solid support. The present invention also provides a supported planar lipid bilayer, where the planar lipid bilayer is made of naturally occurring lipids and the solid support is made of unmodified gold or titanium oxide. Preferably, the supported planar lipid bilayer is continuous. The planar lipid bilayer may be made of any naturally occurring lipid or mixture of lipids, including, but not limited to phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinsitol, cardiolipin, cholesterol, and sphingomyelin.

  7. Genetics Home Reference: Neutral lipid storage disease with myopathy

    MedlinePLUS

    ... Recent literature OMIM Genetic disorder catalog Conditions > Neutral lipid storage disease with myopathy On this page: Description ... Glossary definitions Reviewed February 2014 What is neutral lipid storage disease with myopathy? Neutral lipid storage disease ...

  8. Nanoplasmonic ruler to measure lipid vesicle deformation.

    PubMed

    Jackman, Joshua A; Špa?ková, Barbora; Linardy, Eric; Kim, Min Chul; Yoon, Bo Kyeong; Homola, Ji?í; Cho, Nam-Joon

    2015-12-15

    A nanoplasmonic ruler method is presented in order to measure the deformation of adsorbed, nm-scale lipid vesicles on solid supports. It is demonstrated that single adsorbed vesicles undergo greater deformation on silicon oxide over titanium oxide, offering direct experimental evidence to support membrane tension-based theoretical models of supported lipid bilayer formation. PMID:26466086

  9. Lipid-Based Drug Delivery Systems

    PubMed Central

    Shrestha, Hina; Bala, Rajni; Arora, Sandeep

    2014-01-01

    The principle objective of formulation of lipid-based drugs is to enhance their bioavailability. The use of lipids in drug delivery is no more a new trend now but is still the promising concept. Lipid-based drug delivery systems (LBDDS) are one of the emerging technologies designed to address challenges like the solubility and bioavailability of poorly water-soluble drugs. Lipid-based formulations can be tailored to meet a wide range of product requirements dictated by disease indication, route of administration, cost consideration, product stability, toxicity, and efficacy. These formulations are also a commercially viable strategy to formulate pharmaceuticals, for topical, oral, pulmonary, or parenteral delivery. In addition, lipid-based formulations have been shown to reduce the toxicity of various drugs by changing the biodistribution of the drug away from sensitive organs. However, the number of applications for lipid-based formulations has expanded as the nature and type of active drugs under investigation have become more varied. This paper mainly focuses on novel lipid-based formulations, namely, emulsions, vesicular systems, and lipid particulate systems and their subcategories as well as on their prominent applications in pharmaceutical drug delivery. PMID:26556202

  10. Lipid Profiles and Signals for Long Life.

    PubMed

    Schroeder, Elizabeth A; Brunet, Anne

    2015-11-01

    Historically, fat was considered detrimental to health and lifespan. However, lipidomics, the quantification of all lipid molecules in a biological sample, and genetic studies in model organisms are revealing specific fats that may promote longevity. These emerging findings provide insight into the complex relationship between lipids and longevity. PMID:26439976

  11. Do lipids influence the allergic sensitization process?

    PubMed

    Bublin, Merima; Eiwegger, Thomas; Breiteneder, Heimo

    2014-09-01

    Allergic sensitization is a multifactorial process that is not only influenced by the allergen and its biological function per se but also by other small molecular compounds, such as lipids, that are directly bound as ligands by the allergen or are present in the allergen source. Several members of major allergen families bind lipid ligands through hydrophobic cavities or electrostatic or hydrophobic interactions. These allergens include certain seed storage proteins, Bet v 1-like and nonspecific lipid transfer proteins from pollens and fruits, certain inhalant allergens from house dust mites and cockroaches, and lipocalins. Lipids from the pollen coat and furry animals and the so-called pollen-associated lipid mediators are codelivered with the allergens and can modulate the immune responses of predisposed subjects by interacting with the innate immune system and invariant natural killer T cells. In addition, lipids originating from bacterial members of the pollen microbiome contribute to the outcome of the sensitization process. Dietary lipids act as adjuvants and might skew the immune response toward a TH2-dominated phenotype. In addition, the association with lipids protects food allergens from gastrointestinal degradation and facilitates their uptake by intestinal cells. These findings will have a major influence on how allergic sensitization will be viewed and studied in the future. PMID:24880633

  12. Biosynthesis of archaeal membrane ether lipids

    PubMed Central

    Jain, Samta; Caforio, Antonella; Driessen, Arnold J. M.

    2014-01-01

    A vital function of the cell membrane in all living organism is to maintain the membrane permeability barrier and fluidity. The composition of the phospholipid bilayer is distinct in archaea when compared to bacteria and eukarya. In archaea, isoprenoid hydrocarbon side chains are linked via an ether bond to the sn-glycerol-1-phosphate backbone. In bacteria and eukarya on the other hand, fatty acid side chains are linked via an ester bond to the sn-glycerol-3-phosphate backbone. The polar head groups are globally shared in the three domains of life. The unique membrane lipids of archaea have been implicated not only in the survival and adaptation of the organisms to extreme environments but also to form the basis of the membrane composition of the last universal common ancestor (LUCA). In nature, a diverse range of archaeal lipids is found, the most common are the diether (or archaeol) and the tetraether (or caldarchaeol) lipids that form a monolayer. Variations in chain length, cyclization and other modifications lead to diversification of these lipids. The biosynthesis of these lipids is not yet well understood however progress in the last decade has led to a comprehensive understanding of the biosynthesis of archaeol. This review describes the current knowledge of the biosynthetic pathway of archaeal ether lipids; insights on the stability and robustness of archaeal lipid membranes; and evolutionary aspects of the lipid divide and the LUCA. It examines recent advances made in the field of pathway reconstruction in bacteria. PMID:25505460

  13. Do lipids influence the allergic sensitization process?

    PubMed Central

    Bublin, Merima; Eiwegger, Thomas; Breiteneder, Heimo

    2014-01-01

    Allergic sensitization is a multifactorial process that is not only influenced by the allergen and its biological function per se but also by other small molecular compounds, such as lipids, that are directly bound as ligands by the allergen or are present in the allergen source. Several members of major allergen families bind lipid ligands through hydrophobic cavities or electrostatic or hydrophobic interactions. These allergens include certain seed storage proteins, Bet v 1–like and nonspecific lipid transfer proteins from pollens and fruits, certain inhalant allergens from house dust mites and cockroaches, and lipocalins. Lipids from the pollen coat and furry animals and the so-called pollen-associated lipid mediators are codelivered with the allergens and can modulate the immune responses of predisposed subjects by interacting with the innate immune system and invariant natural killer T cells. In addition, lipids originating from bacterial members of the pollen microbiome contribute to the outcome of the sensitization process. Dietary lipids act as adjuvants and might skew the immune response toward a TH2-dominated phenotype. In addition, the association with lipids protects food allergens from gastrointestinal degradation and facilitates their uptake by intestinal cells. These findings will have a major influence on how allergic sensitization will be viewed and studied in the future. PMID:24880633

  14. Pasting characteristics of starch-lipid composites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-lipid composites (SLC) have been used as fat replacers and stabilizers in beef patties, dairy products, and baked goods. The SLC are produced by mixing aqueous starch slurry with a lipid source, and steam jet-cooking. The SLC may be dried using a drum drier and then milled in a Retch mill. ...

  15. Lipid transport and human brain development.

    PubMed

    Betsholtz, Christer

    2015-07-01

    How the human brain rapidly builds up its lipid content during brain growth and maintains its lipids in adulthood has remained elusive. Two new studies show that inactivating mutations in MFSD2A, known to be expressed specifically at the blood-brain barrier, lead to microcephaly, thereby offering a simple and surprising solution to an old enigma. PMID:26111510

  16. Lipid extraction from isolated single nerve cells

    NASA Technical Reports Server (NTRS)

    Krasnov, I. V.

    1977-01-01

    A method of extracting lipids from single neurons isolated from lyophilized tissue is described. The method permits the simultaneous extraction of lipids from 30-40 nerve cells and for each cell provides equal conditions of solvent removal at the conclusion of extraction.

  17. Imaging lipid droplets in Arabidopsis mutants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Confocal fluorescence microscopy was adapted for the imaging of neutral lipids in plant leaves with defects in normal lipid metabolism using two different fluorescent dyes. Disruptions in a gene locus, At4g24160, yielded Arabidopsis thaliana plants with a preponderance of oil bodies in their leaves ...

  18. Multichannel taste sensors with lipid, lipid like polymer membranes

    NASA Astrophysics Data System (ADS)

    Szpakowska, M.; Szwacki, J.; Marja?ska, E.

    2008-08-01

    The elaboration of a sensitive taste sensor for discrimination of different soft drinks is very important in food industry. The short review of taste sensors described in the literature is presented. Two types of potentiometric taste sensors, one with lipophilic compound-polymer membranes (ISE) and the other with lipid polymer membrane and a conducting polymer film (All solid state electrode, ASSE) were tested in appropriate taste solutions. Five channel ISE sensor was examined in acid, sour and sweet solutions. This sensor was sensitive to bitter and sour substances and not too sensitive to sucrose concentration. It was successfully used for discrimination of different kind of soft drinks. Four channel ASSE sensor was examined in sour solutions. It was found that stability and sensitivity of ASSE are lower than ISE. Therefore, it seems that the previous one cannot be applied in taste sensor.

  19. Lxr-driven enterocyte lipid droplet formation delays transport of ingested lipids.

    PubMed

    Cruz-Garcia, Lourdes; Schlegel, Amnon

    2014-09-01

    Liver X receptors (Lxrs) are master regulators of cholesterol catabolism, driving the elimination of cholesterol from the periphery to the lumen of the intestine. Development of pharmacological agents to activate Lxrs has been hindered by synthetic Lxr agonists' induction of hepatic lipogenesis and hypertriglyceridemia. Elucidating the function of Lxrs in regulating enterocyte lipid handling might identify novel aspects of lipid metabolism that are pharmacologically amenable. We took a genetic approach centered on the single Lxr gene nr1h3 in zebrafish to study the role of Lxr in enterocyte lipid metabolism. Loss of nr1h3 function causes anticipated gene regulatory changes and cholesterol intolerance, collectively reflecting high evolutionary conservation of zebrafish Lxra function. Intestinal nr1h3 activation delays transport of absorbed neutral lipids, with accumulation of neutral lipids in enterocyte cytoplasmic droplets. This delay in transport of ingested neutral lipids protects animals from hypercholesterolemia and hepatic steatosis induced by a high-fat diet. On a gene regulatory level, Lxra induces expression of acsl3a, which encodes acyl-CoA synthetase long-chain family member 3a, a lipid droplet-anchored protein that directs fatty acyl chains into lipids. Forced overexpression of acls3a in enterocytes delays, in part, the appearance of neutral lipids in the vasculature of zebrafish larvae. Activation of Lxr in the intestine cell-autonomously regulates the rate of delivery of absorbed lipids by inducting a temporary lipid intestinal droplet storage depot. PMID:25030662

  20. Altered renal lipid metabolism and renal lipid accumulation in human diabetic nephropathy.

    PubMed

    Herman-Edelstein, Michal; Scherzer, Pnina; Tobar, Ana; Levi, Moshe; Gafter, Uzi

    2014-03-01

    Animal models link ectopic lipid accumulation to renal dysfunction, but whether this process occurs in the human kidney is uncertain. To this end, we investigated whether altered renal TG and cholesterol metabolism results in lipid accumulation in human diabetic nephropathy (DN). Lipid staining and the expression of lipid metabolism genes were studied in kidney biopsies of patients with diagnosed DN (n = 34), and compared with normal kidneys (n = 12). We observed heavy lipid deposition and increased intracellular lipid droplets. Lipid deposition was associated with dysregulation of lipid metabolism genes. Fatty acid ?-oxidation pathways including PPAR-?, carnitine palmitoyltransferase 1, acyl-CoA oxidase, and L-FABP were downregulated. Downregulation of renal lipoprotein lipase, which hydrolyzes circulating TGs, was associated with increased expression of angiopoietin-like protein 4. Cholesterol uptake receptor expression, including LDL receptors, oxidized LDL receptors, and acetylated LDL receptors, was significantly increased, while there was downregulation of genes effecting cholesterol efflux, including ABCA1, ABCG1, and apoE. There was a highly significant correlation between glomerular filtration rate, inflammation, and lipid metabolism genes, supporting a possible role of abnormal lipid metabolism in the pathogenesis of DN. These data suggest that renal lipid metabolism may serve as a target for specific therapies aimed at slowing the progression of glomerulosclerosis. PMID:24371263

  1. The Physics of Stratum Corneum Lipid Membranes

    E-print Network

    Das, Chinmay

    2015-01-01

    The Stratum Corneum (SC), the outermost layer of skin, comprises rigid corneocytes (keratin filled dead cells) in a specialized lipid matrix. The continuous lipid matrix provides the main barrier against uncontrolled water loss and invasion of external pathogens. Unlike all other biological lipid membranes (like intracellular organelles and plasma membranes), molecules in SC lipid matrix show small hydrophilic group and large variability in the length of the alkyl tails and in the numbers and positions of groups that are capable of forming hydrogen bonds. Molecular simulations provide a route for systematically probing the effects of each of these differences separately. In this article we present results from atomistic molecular dynamics of selected lipid bilayers and multilayers to probe the effect of these polydispersities.

  2. Model answers to lipid membrane questions.

    PubMed

    Mouritsen, Ole G

    2011-09-01

    Ever since it was discovered that biological membranes have a core of a bimolecular sheet of lipid molecules, lipid bilayers have been a model laboratory for investigating physicochemical and functional properties of biological membranes. Experimental and theoretical models help the experimental scientist to plan experiments and interpret data. Theoretical models are the theoretical scientist's preferred toys to make contact between membrane theory and experiments. Most importantly, models serve to shape our intuition about which membrane questions are the more fundamental and relevant ones to pursue. Here we review some membrane models for lipid self-assembly, monolayers, bilayers, liposomes, and lipid-protein interactions and illustrate how such models can help answering questions in modern lipid cell biology. PMID:21610116

  3. The Physics of Stratum Corneum Lipid Membranes

    E-print Network

    Chinmay Das; Peter D. Olmsted

    2015-10-29

    The Stratum Corneum (SC), the outermost layer of skin, comprises rigid corneocytes (keratin filled dead cells) in a specialized lipid matrix. The continuous lipid matrix provides the main barrier against uncontrolled water loss and invasion of external pathogens. Unlike all other biological lipid membranes (like intracellular organelles and plasma membranes), molecules in SC lipid matrix show small hydrophilic group and large variability in the length of the alkyl tails and in the numbers and positions of groups that are capable of forming hydrogen bonds. Molecular simulations provide a route for systematically probing the effects of each of these differences separately. In this article we present results from atomistic molecular dynamics of selected lipid bilayers and multilayers to probe the effect of these polydispersities.

  4. Lipid-based biofuel production from wastewater.

    PubMed

    Muller, Emilie E L; Sheik, Abdul R; Wilmes, Paul

    2014-12-01

    Increasing world population, urbanization and industrialization are driving global increases in wastewater production. Wastewater comprises significant amounts of chemical energy primarily in the form of organic molecules (in particular lipids), which are currently not being recovered comprehensively. Within biological wastewater treatment (BWWT) systems, specialized microorganisms assimilate and store lipids anaerobically. These intracellular stores represent interesting feedstocks for biofuel synthesis. Here, we review our current understanding of the genetic and functional basis for bacterial lipid accumulation and processing, and relate this to lipid accumulating bacterial populations which occur naturally in BWWT plants. A grand challenge for microbial ecologists and engineers now lies in translating this knowledge into the design of new BWWT processes for the comprehensive recovery of lipids from wastewater streams and their subsequent conversion into biofuel. PMID:24768793

  5. Influence of protein and lipid domains on the structure, fluidity and phase behavior of lipid bilayer membranes

    E-print Network

    Horton, Margaret R. (Margaret Ruth)

    2007-01-01

    The lipid bilayer forms the basic structure of the cell membrane, which is a heterogeneous matrix of proteins and lipids that provides a barrier between the interior of a cell and its outside environment. Protein and lipid ...

  6. Structure determination of lipid bilayers.

    PubMed Central

    Worthington, C R; Kharf, R S

    1978-01-01

    A method of determining the phases of X-ray reflections from oriented model membrane systems at low resolution is described. The method involves deconvolution and requires that d less than or equal to 2v where v is the width of the head group region within the bilayer and d is the thickness of the bilayer. The method can be used with a single set of X-ray data and applies to lipid bilayers which have a relatively constant density in the hydrocarbon region. Phases for the first five or six orders of phosphatidylethanolamine and lecithin are derived. A refined analysis based upon deconvolution but using information inherent in the Fourier profile is also described. PMID:698345

  7. Interfacial & colloidal aspects of lipid digestion.

    PubMed

    Wilde, P J; Chu, B S

    2011-06-01

    Amongst the main issues challenging the food manufacturing sector, health and nutrition are becoming increasingly important. Global concerns such as obesity, the ageing population and food security will have to be addressed. Food security is not just about assuring food supply, but is also about optimising nutritional delivery from the food that is available [1]. Therefore one challenge is to optimise the health benefits from the lipids and lipid soluble nutrients. Colloid scientists have an affinity for lipids because they are water insoluble, however this presents a challenge to the digestive system, which has to convert them to structures that are less insoluble so they are available for uptake. Despite this, the human digestive system is remarkably effective at digesting and absorbing most lipids. This is primarily driven through maximising energy intake, as lipids possess the highest calorific value, which was a survival trait to survive times of famine, but is now an underlying cause of obesity in developed countries with high food availability. The critical region here is the lipid-water interface, where the key reactions take place to solubilise lipids and lipid soluble nutrients. Digestive lipases have to adsorb to the oil water interface in order to hydrolyse triacylglycerols into fatty acids and mono glycerides, which accumulate at the interface [2], and inhibit lipase activity. Pancreatic lipase, which is responsible for the majority of lipid hydrolysis, also requires the action of bile salts and colipase to function effectively. Bile salts both aid the adsorption of co-lipase and lipase, and help solubilise the lipolysis products which have accumulated at the interface, into mixed micelles composing bile salts and a range of other lipids, to facilitate transport to the gut mucosal surface prior to uptake and absorption. The process can be affected by the lipid type, as shorter chain, fatty acids are more easily absorbed, whereas the uptake of longer chain fatty acids, particularly the very long chain n-3 fatty acids from fish oils are dependent on source and so may depend on food microstructure for optimal uptake [3]. The uptake of some poorly water soluble nutrients are enhanced by the presence of lipids, but the mechanisms are not clear. In addition, controlling the digestion of lipids can be beneficial as slower release of lipids into the bloodstream can reduce risk of cardiovascular disease, and can promote gut feedback processes that reduce appetite. This presents an opportunity to colloid and interfacial science, as there are many unanswered questions regarding the specific physicochemical mechanisms underlying the process of lipid digestion and uptake. I will review our current knowledge of lipid digestion and present examples of how fundamental research in colloidal and interface science is beginning to address these issues. These include the adsorption behaviour of physiological surfactants such as bile salts; interfacial processes by which different polar lipids can influence lipolysis; and the effect of emulsion based delivery systems on cellular uptake of lipid soluble nutrients. A fundamental understanding of these processes is required if we are to develop intelligent design strategies for foods that will deliver optimal nutrition and improved health benefits in order to address the global challenges facing the food sector in the future. PMID:21377138

  8. Lipid-Based Nanocarriers for RNA Delivery

    PubMed Central

    Xue, Hui Yi; Guo, Pengbo; Wen, Wu-Cheng; Wong, Ho Lun

    2015-01-01

    RNA-interference (RNAi) agents such as small-interfering RNA (siRNA) and micro-RNA (miRNA) have strong potential as therapeutic agents for the treatment of a broad range of diseases such as malignancies, infections, autoimmune diseases and neurological diseases that are associated with undesirable gene expression. In recent years, several clinical trials of RNAi therapeutics especially siRNAs have been conducted with limited success so far. For systemic administration of these poorly permeable and easily degradable macromolecules, it is obvious that a safe and efficient delivery platform is highly desirable. Because of high biocompatibility, biodegradability and solid track record for clinical use, nanocarriers made of lipids and/or phospholipids have been commonly employed to facilitate RNA delivery. In this article, the key features of the major sub-classes of lipid-based nanocarriers, e.g. liposomes, lipid nanoparticles and lipid nanoemulsions, will be reviewed. Focus of the discussion is on the various challenges researchers face when developing lipid-based RNA nanocarriers, such as the toxicity of cationic lipids and issues related to PEGylated lipids, as well as the strategies employed in tackling these challenges. It is hoped that by understanding more about the pros and cons of these most frequently used RNA delivery systems, the pharmaceutical scientists, biomedical researchers and clinicians will be more successful in overcoming some of the obstacles that currently limit the clinical translation of RNAi therapy. PMID:26027572

  9. The lipid raft proteome of Borrelia burgdorferi.

    PubMed

    Toledo, Alvaro; Pérez, Alberto; Coleman, James L; Benach, Jorge L

    2015-11-01

    Eukaryotic lipid rafts are membrane microdomains that have significant amounts of cholesterol and a selective set of proteins that have been associated with multiple biological functions. The Lyme disease agent, Borrelia burgdorferi, is one of an increasing number of bacterial pathogens that incorporates cholesterol onto its membrane, and form cholesterol glycolipid domains that possess all the hallmarks of eukaryotic lipid rafts. In this study, we isolated lipid rafts from cultured B. burgdorferi as a detergent resistant membrane (DRM) fraction on density gradients, and characterized those molecules that partitioned exclusively or are highly enriched in these domains. Cholesterol glycolipids, the previously known raft-associated lipoproteins OspA and OpsB, and cholera toxin partitioned into the lipid rafts fraction indicating compatibility with components of the DRM. The proteome of lipid rafts was analyzed by a combination of LC-MS/MS or MudPIT. Identified proteins were analyzed in silico for parameters that included localization, isoelectric point, molecular mass and biological function. The proteome provided a consistent pattern of lipoproteins, proteases and their substrates, sensing molecules and prokaryotic homologs of eukaryotic lipid rafts. This study provides the first analysis of a prokaryotic lipid raft and has relevance for the biology of Borrelia, other pathogenic bacteria, as well as for the evolution of these structures. All MS data have been deposited in the ProteomeXchange with identifier PXD002365 (http://proteomecentral.proteomexchange.org/dataset/PXD002365). PMID:26256460

  10. Membrane domains and the "lipid raft" concept.

    PubMed

    Sonnino, S; Prinetti, A

    2013-01-01

    The bulk structure of biological membranes consists of a bilayer of amphipathic lipids. According to the fluid mosaic model proposed by Singer and Nicholson, the glycerophospholipid bilayer is a two-dimensional fluid construct that allows the lateral movement of membrane components. Different types of lateral interactions among membrane components can take place, giving rise to multiple levels of lateral order that lead to highly organized structures. Early observations suggested that some of the lipid components of biological membranes may play active roles in the creation of these levels of order. In the late 1980s, a diverse series of experimental findings collectively gave rise to the lipid raft hypothesis. Lipid rafts were originally defined as membrane domains, i.e., ordered structures created as a consequence of the lateral segregation of sphingolipids and differing from the surrounding membrane in their molecular composition and properties. This definition was subsequently modified to introduce the notion that lipid rafts correspond to membrane areas stabilized by the presence of cholesterol within a liquid-ordered phase. During the past two decades, the concept of lipid rafts has become extremely popular among cell biologists, and these structures have been suggested to be involved in a great variety of cellular functions and biological events. During the same period, however, some groups presented experimental evidence that appeared to contradict the basic tenets that underlie the lipid raft concept. The concept is currently being re-defined, with greater consistency regarding the true nature and role of lipid rafts. In this article we will review the concepts, criticisms, and the novel confirmatory findings relating to the lipid raft hypothesis. PMID:23150999

  11. Curvature and Lipid Packing Modulate the Elastic Properties of Lipid Assemblies: Comparing HII and Lamellar Phases.

    PubMed

    Johner, Niklaus; Harries, Daniel; Khelashvili, George

    2014-12-01

    Accumulating evidence indicates that membrane reshaping and fusion processes, as well as regulation of membrane protein function, depend on lipid composition. Although it is widely accepted that cell membranes are under considerable stress and frustration and can be locally highly curved, experimental approaches to determine the material properties of lipids usually rely on their study in a relaxed environment or in flat bilayers. Here, we propose a computational method to determine the elastic properties of lipid assemblies of arbitrarily shaped interfaces and apply it to lipidic mixtures in the inverted hexagonal and lamellar phases. We find that the bending rigidity critically depends on the geometry of the system and correlates with the changes in lipid chain order imposed by the specific environment. Our results are relevant for resolving local lipid properties of deformed, stressed, or frustrated membranes that notably emerge around integral membrane proteins or during different membrane remodeling processes. PMID:26278954

  12. Formation and Characterization of Supported Lipid Bilayers Composed of Hydrogenated and Deuterated Escherichia coli Lipids

    PubMed Central

    Lind, Tania Kjellerup; Wacklin, Hanna; Schiller, Jürgen; Moulin, Martine; Haertlein, Michael; Pomorski, Thomas Günther; Cárdenas, Marité

    2015-01-01

    Supported lipid bilayers are widely used for sensing and deciphering biomolecular interactions with model cell membranes. In this paper, we present a method to form supported lipid bilayers from total lipid extracts of Escherichia coli by vesicle fusion. We show the validity of this method for different types of extracts including those from deuterated biomass using a combination of complementary surface sensitive techniques; quartz crystal microbalance, neutron reflection and atomic force microscopy. We find that the head group composition of the deuterated and the hydrogenated lipid extracts is similar (approximately 75% phosphatidylethanolamine, 13% phosphatidylglycerol and 12% cardiolipin) and that both samples can be used to reconstitute high-coverage supported lipid bilayers with a total thickness of 41 ± 3 Å, common for fluid membranes. The formation of supported lipid bilayers composed of natural extracts of Escherichia coli allow for following biomolecular interactions, thus advancing the field towards bacterial-specific membrane biomimics. PMID:26658241

  13. Characterization of lipid DNA interactions. I. Destabilization of bound lipids and DNA dissociation.

    PubMed Central

    Harvie, P; Wong, F M; Bally, M B

    1998-01-01

    We have recently described a method for preparing lipid-based DNA particles (LDPs) that form spontaneously when detergent-solubilized cationic lipids are mixed with DNA. LDPs have the potential to be developed as carriers for use in gene therapy. More importantly, the lipid-DNA interactions that give rise to particle formation can be studied to gain a better understanding of factors that govern lipid binding and lipid dissociation. In this study the stability of lipid-DNA interactions was evaluated by measurement of DNA protection (binding of the DNA intercalating dye TO-PRO-1 and sensitivity to DNase I) and membrane destabilization (lipid mixing reactions measured by fluorescence resonance energy transfer techniques) after the addition of anionic liposomes. Lipid-based DNA transfer systems were prepared with pInexCAT v.2.0, a 4.49-kb plasmid expression vector that contains the marker gene for chloramphenicol acetyltransferase (CAT). LDPs were prepared using N-N-dioleoyl-N,N-dimethylammonium chloride (DODAC) and either 1, 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or 1, 2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). For comparison, liposome/DNA aggregates (LDAs) were also prepared by using preformed DODAC/DOPE (1:1 mole ratio) and DODAC/DOPC (1:1 mole ratio) liposomes. The addition of anionic liposomes to the lipid-based DNA formulations initiated rapid membrane destabilization as measured by the resonance energy transfer lipid-mixing assay. It is suggested that lipid mixing is a reflection of processes (contact, dehydration, packing defects) that lead to formulation disassembly and DNA release. This destabilization reaction was associated with an increase in DNA sensitivity to DNase I, and anionic membrane-mediated destabilization was not dependent on the incorporation of DOPE. These results are interpreted in terms of factors that regulate the disassembly of lipid-based DNA formulations. PMID:9675205

  14. Improved Characterization of EV Preparations Based on Protein to Lipid Ratio and Lipid Properties

    PubMed Central

    Osteikoetxea, Xabier; Balogh, Andrea; Szabó-Taylor, Katalin; Németh, Andrea; Szabó, Tamás Géza; Pálóczi, Krisztina; Sódar, Barbara; Kittel, Ágnes; György, Bence; Pállinger, Éva; Matkó, János; Buzás, Edit Irén

    2015-01-01

    In recent years the study of extracellular vesicles has gathered much scientific and clinical interest. As the field is expanding, it is becoming clear that better methods for characterization and quantification of extracellular vesicles as well as better standards to compare studies are warranted. The goal of the present work was to find improved parameters to characterize extracellular vesicle preparations. Here we introduce a simple 96 well plate-based total lipid assay for determination of lipid content and protein to lipid ratios of extracellular vesicle preparations from various myeloid and lymphoid cell lines as well as blood plasma. These preparations included apoptotic bodies, microvesicles/microparticles, and exosomes isolated by size-based fractionation. We also investigated lipid bilayer order of extracellular vesicle subpopulations using Di-4-ANEPPDHQ lipid probe, and lipid composition using affinity reagents to clustered cholesterol (monoclonal anti-cholesterol antibody) and ganglioside GM1 (cholera toxin subunit B). We have consistently found different protein to lipid ratios characteristic for the investigated extracellular vesicle subpopulations which were substantially altered in the case of vesicular damage or protein contamination. Spectral ratiometric imaging and flow cytometric analysis also revealed marked differences between the various vesicle populations in their lipid order and their clustered membrane cholesterol and GM1 content. Our study introduces for the first time a simple and readily available lipid assay to complement the widely used protein assays in order to better characterize extracellular vesicle preparations. Besides differentiating extracellular vesicle subpopulations, the novel parameters introduced in this work (protein to lipid ratio, lipid bilayer order, and lipid composition), may prove useful for quality control of extracellular vesicle related basic and clinical studies. PMID:25798862

  15. Improved characterization of EV preparations based on protein to lipid ratio and lipid properties.

    PubMed

    Osteikoetxea, Xabier; Balogh, Andrea; Szabó-Taylor, Katalin; Németh, Andrea; Szabó, Tamás Géza; Pálóczi, Krisztina; Sódar, Barbara; Kittel, Ágnes; György, Bence; Pállinger, Éva; Matkó, János; Buzás, Edit Irén

    2015-01-01

    In recent years the study of extracellular vesicles has gathered much scientific and clinical interest. As the field is expanding, it is becoming clear that better methods for characterization and quantification of extracellular vesicles as well as better standards to compare studies are warranted. The goal of the present work was to find improved parameters to characterize extracellular vesicle preparations. Here we introduce a simple 96 well plate-based total lipid assay for determination of lipid content and protein to lipid ratios of extracellular vesicle preparations from various myeloid and lymphoid cell lines as well as blood plasma. These preparations included apoptotic bodies, microvesicles/microparticles, and exosomes isolated by size-based fractionation. We also investigated lipid bilayer order of extracellular vesicle subpopulations using Di-4-ANEPPDHQ lipid probe, and lipid composition using affinity reagents to clustered cholesterol (monoclonal anti-cholesterol antibody) and ganglioside GM1 (cholera toxin subunit B). We have consistently found different protein to lipid ratios characteristic for the investigated extracellular vesicle subpopulations which were substantially altered in the case of vesicular damage or protein contamination. Spectral ratiometric imaging and flow cytometric analysis also revealed marked differences between the various vesicle populations in their lipid order and their clustered membrane cholesterol and GM1 content. Our study introduces for the first time a simple and readily available lipid assay to complement the widely used protein assays in order to better characterize extracellular vesicle preparations. Besides differentiating extracellular vesicle subpopulations, the novel parameters introduced in this work (protein to lipid ratio, lipid bilayer order, and lipid composition), may prove useful for quality control of extracellular vesicle related basic and clinical studies. PMID:25798862

  16. Lipid-altering therapy and atrial fibrillation.

    PubMed

    Bachmann, Justin M; Majmudar, Maulik; Tompkins, Christine; Blumenthal, Roger S; Marine, Joseph E

    2008-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia with significant morbidity and public health cost. Because of limitations of efficacy and safety of conventional antiarrhythmic agents, alternative therapies for AF are needed. The potential antiarrhythmic properties of lipid-altering therapy, including the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors and fish oils, are increasingly recognized, particularly in light of their potential anti-inflammatory properties. This review examines the known effects of lipid-altering therapy on atrial arrhythmias in both experimental and clinical settings. Inflammatory states, such as post-cardiac surgery and AF of recent onset, show promise as targets. In contrast, lipid-lowering therapy is less likely to affect longstanding persistent AF. Current recommendations for the use of lipid-altering therapy for prevention and treatment of AF are summarized. PMID:18562810

  17. Intercellular Lipid Mediators and GPCR Drug Discovery

    PubMed Central

    Im, Dong-Soon

    2013-01-01

    G-protein-coupled receptors (GPCR) are the largest superfamily of receptors responsible for signaling between cells and tissues, and because they play important physiological roles in homeostasis, they are major drug targets. New technologies have been developed for the identification of new ligands, new GPCR functions, and for drug discovery purposes. In particular, intercellular lipid mediators, such as, lysophosphatidic acid and sphingosine 1-phosphate have attracted much attention for drug discovery and this has resulted in the development of fingolimod (FTY-720) and AM095. The discovery of new intercellular lipid mediators and their GPCRs are discussed from the perspective of drug development. Lipid GPCRs for lysophospholipids, including lysophosphatidylserine, lysophosphatidylinositol, lysophosphatidylcholine, free fatty acids, fatty acid derivatives, and other lipid mediators are reviewed. PMID:24404331

  18. Surface tension and electroporation of lipid bilayers

    E-print Network

    Cho, Han-Jae Jeremy

    2011-01-01

    Electroporation of lipid bilayers is widely used in DNA transfection, gene therapy, and targeted drug delivery and has potential applications in water desalination and filtration. A better, more thorough molecular understanding ...

  19. Early determinants of development: a lipid perspective.

    PubMed

    Carlson, Susan E

    2009-05-01

    This article results from an International Life Sciences Institute workshop on early nutritional determinants of health and development. The presentation on lipids focused mainly on the longer-chain products of the essential fatty acids, particularly docosahexaenoic acid (22:6n-3), and cognitive development as among the most studied lipids and outcomes, respectively, in early human nutrition. Because there have been several recent reviews on this topic, the present review takes a broader perspective with respect to both early development and lipids: an expanded research agenda is plausible on the basis of observations from some human studies and from animal studies. Other lipids known to be provided in variable amounts to infants through human milk are cholesterol and gangliosides. Short sections address the current state of knowledge and some questions that could be pursued. PMID:19321568

  20. Lipid Peroxidation in Higher Plants 1

    PubMed Central

    Schmidt, Arno; Kunert, Karl Josef

    1986-01-01

    To study the role of glutathione reductase in lipid peroxidation, bean leaves (Phaseolus vulgaris) cv Fori were treated with the herbicide acifluorfen-sodium (sodium 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid). Acifluorfen is a potent inducer of lipid peroxidation. In beans, decrease of acid-soluble SH-compounds and lipid peroxidation, measured as ethane evolution, were the toxic events after treatment of leaves with acifluorfen. As a primary response to peroxidation, increased production of antioxidants, such as vitamin C and glutathione, was found. This was followed by elevation of glutathione reductase activity. Enhanced activity of the enzyme prevented both further decline of acid-soluble SH-compounds and lipid peroxidation. Increased production of antioxidants and elevated activity of antioxidative enzymes, like glutathione reductase, seem to be a general strategy to limit toxic peroxidation in plants. PMID:16665095

  1. Supported lipid bilayer/carbon nanotube hybrids

    NASA Astrophysics Data System (ADS)

    Zhou, Xinjian; Moran-Mirabal, Jose M.; Craighead, Harold G.; McEuen, Paul L.

    2007-03-01

    Carbon nanotube transistors combine molecular-scale dimensions with excellent electronic properties, offering unique opportunities for chemical and biological sensing. Here, we form supported lipid bilayers over single-walled carbon nanotube transistors. We first study the physical properties of the nanotube/supported lipid bilayer structure using fluorescence techniques. Whereas lipid molecules can diffuse freely across the nanotube, a membrane-bound protein (tetanus toxin) sees the nanotube as a barrier. Moreover, the size of the barrier depends on the diameter of the nanotube-with larger nanotubes presenting bigger obstacles to diffusion. We then demonstrate detection of protein binding (streptavidin) to the supported lipid bilayer using the nanotube transistor as a charge sensor. This system can be used as a platform to examine the interactions of single molecules with carbon nanotubes and has many potential applications for the study of molecular recognition and other biological processes occurring at cell membranes.

  2. Metabolic engineering of lipid catabolism increases microalgal lipid accumulation without compromising growth

    PubMed Central

    Trentacoste, Emily M.; Shrestha, Roshan P.; Smith, Sarah R.; Glé, Corine; Hartmann, Aaron C.; Hildebrand, Mark; Gerwick, William H.

    2013-01-01

    Biologically derived fuels are viable alternatives to traditional fossil fuels, and microalgae are a particularly promising source, but improvements are required throughout the production process to increase productivity and reduce cost. Metabolic engineering to increase yields of biofuel-relevant lipids in these organisms without compromising growth is an important aspect of advancing economic feasibility. We report that the targeted knockdown of a multifunctional lipase/phospholipase/acyltransferase increased lipid yields without affecting growth in the diatom Thalassiosira pseudonana. Antisense-expressing knockdown strains 1A6 and 1B1 exhibited wild-type–like growth and increased lipid content under both continuous light and alternating light/dark conditions. Strains 1A6 and 1B1, respectively, contained 2.4- and 3.3-fold higher lipid content than wild-type during exponential growth, and 4.1- and 3.2-fold higher lipid content than wild-type after 40 h of silicon starvation. Analyses of fatty acids, lipid classes, and membrane stability in the transgenic strains suggest a role for this enzyme in membrane lipid turnover and lipid homeostasis. These results demonstrate that targeted metabolic manipulations can be used to increase lipid accumulation in eukaryotic microalgae without compromising growth. PMID:24248374

  3. PAT proteins, an ancient family of lipid droplet proteins that regulate cellular lipid stores

    PubMed Central

    Bickel, Perry E.; Tansey, John T.; Welte, Michael A.

    2009-01-01

    Summary The PAT family of lipid droplet proteins includes 5 members in mammals: perilipin, adipose differentiation-related protein (ADRP), tail-interacting protein of 47 kiloDaltons (TIP47), S3-12, and OXPAT. Members of this family are also present in evolutionarily distant organisms, including insects, slime molds and fungi. All PAT proteins share sequence similarity and the ability to bind intracellular lipid droplets, either constitutively or in response to metabolic stimuli, such as increased lipid flux into or out of lipid droplets. Positioned at the lipid droplet surface, PAT proteins manage access of other proteins (lipases) to the lipid esters within the lipid droplet core and can interact with cellular machinery important for lipid droplet biogenesis. Genetic variations in the gene for the best characterized of the mammalian PAT proteins, perilipin, have been associated with metabolic phenotypes, including type 2 diabetes mellitus and obesity. In this review, we discuss how the PAT proteins regulate cellular lipid metabolism both in mammals and in model organisms. PMID:19375517

  4. PAT proteins, an ancient family of lipid droplet proteins that regulate cellular lipid stores.

    PubMed

    Bickel, Perry E; Tansey, John T; Welte, Michael A

    2009-06-01

    The PAT family of lipid droplet proteins includes 5 members in mammals: perilipin, adipose differentiation-related protein (ADRP), tail-interacting protein of 47 kDa (TIP47), S3-12, and OXPAT. Members of this family are also present in evolutionarily distant organisms, including insects, slime molds and fungi. All PAT proteins share sequence similarity and the ability to bind intracellular lipid droplets, either constitutively or in response to metabolic stimuli, such as increased lipid flux into or out of lipid droplets. Positioned at the lipid droplet surface, PAT proteins manage access of other proteins (lipases) to the lipid esters within the lipid droplet core and can interact with cellular machinery important for lipid droplet biogenesis. Genetic variations in the gene for the best-characterized of the mammalian PAT proteins, perilipin, have been associated with metabolic phenotypes, including type 2 diabetes mellitus and obesity. In this review, we discuss how the PAT proteins regulate cellular lipid metabolism both in mammals and in model organisms. PMID:19375517

  5. Metabolic engineering of lipid catabolism increases microalgal lipid accumulation without compromising growth.

    PubMed

    Trentacoste, Emily M; Shrestha, Roshan P; Smith, Sarah R; Glé, Corine; Hartmann, Aaron C; Hildebrand, Mark; Gerwick, William H

    2013-12-01

    Biologically derived fuels are viable alternatives to traditional fossil fuels, and microalgae are a particularly promising source, but improvements are required throughout the production process to increase productivity and reduce cost. Metabolic engineering to increase yields of biofuel-relevant lipids in these organisms without compromising growth is an important aspect of advancing economic feasibility. We report that the targeted knockdown of a multifunctional lipase/phospholipase/acyltransferase increased lipid yields without affecting growth in the diatom Thalassiosira pseudonana. Antisense-expressing knockdown strains 1A6 and 1B1 exhibited wild-type-like growth and increased lipid content under both continuous light and alternating light/dark conditions. Strains 1A6 and 1B1, respectively, contained 2.4- and 3.3-fold higher lipid content than wild-type during exponential growth, and 4.1- and 3.2-fold higher lipid content than wild-type after 40 h of silicon starvation. Analyses of fatty acids, lipid classes, and membrane stability in the transgenic strains suggest a role for this enzyme in membrane lipid turnover and lipid homeostasis. These results demonstrate that targeted metabolic manipulations can be used to increase lipid accumulation in eukaryotic microalgae without compromising growth. PMID:24248374

  6. Bilayer Deformation, Pores, and Micellation Induced by Oxidized Lipids.

    PubMed

    Boonnoy, Phansiri; Jarerattanachat, Viwan; Karttunen, Mikko; Wong-Ekkabut, Jirasak

    2015-12-17

    The influence of different oxidized lipids on lipid bilayers was investigated with 16 individual 1 ?s atomistic molecular dynamics (MD) simulations. Binary mixtures of lipid bilayers of 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphatidylcholine (PLPC) and its peroxide and aldehyde products were performed at different concentrations. In addition, an asymmetrical short chain lipid, 1-palmitoyl-2-decanoyl-sn-glycero-3-phosphatidylcholine (PDPC), was used to compare the effects of polar/apolar groups in the lipid tail on lipid bilayer. Although water defects occurred with both aldehyde and peroxide lipids, full pore formation was observed only for aldehyde lipids. At medium concentrations the pores were stable. At higher concentrations, however, the pores became unstable and micellation occurred. Data analysis shows that aldehyde lipids' propensity for pore formation is due to their shorter and highly mobile tail. The highly polar peroxide lipids are stabilized by strong hydrogen bonds with interfacial water. PMID:26673194

  7. Targeting bacteria via iminoboronate chemistry of amine-presenting lipids.

    PubMed

    Bandyopadhyay, Anupam; McCarthy, Kelly A; Kelly, Michael A; Gao, Jianmin

    2015-01-01

    Synthetic molecules that target specific lipids serve as powerful tools for understanding membrane biology and may also enable new applications in biotechnology and medicine. For example, selective recognition of bacterial lipids may give rise to novel antibiotics, as well as diagnostic methods for bacterial infection. Currently known lipid-binding molecules primarily rely on noncovalent interactions to achieve lipid selectivity. Here we show that targeted recognition of lipids can be realized by selectively modifying the lipid of interest via covalent bond formation. Specifically, we report an unnatural amino acid that preferentially labels amine-presenting lipids via iminoboronate formation under physiological conditions. By targeting phosphatidylethanolamine and lysylphosphatidylglycerol, the two lipids enriched on bacterial cell surfaces, the iminoboronate chemistry allows potent labelling of Gram-positive bacteria even in the presence of 10% serum, while bypassing mammalian cells and Gram-negative bacteria. The covalent strategy for lipid recognition should be extendable to other important membrane lipids. PMID:25761996

  8. Perfluorooctanoic acid rigidifies a model lipid membrane

    E-print Network

    Beate-Annette Bruening; Bela Farago

    2014-05-05

    We report a combined dynamic light scattering and neutron spin-echo (NSE) study on vesicles composed of the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine under the influence of varying amounts of perfluorooctanoic acid. We study local lipid bilayer undulations using NSE on time scales up to 200 ns. Similar to the effect evoked by cholesterol, we attribute the observed lipid bilayer stiffening to a condensing effect of the perfluorinated compound on the membrane.

  9. Perfluorooctanoic acid rigidifies a model lipid membrane

    NASA Astrophysics Data System (ADS)

    Brüning, B.; Farago, B.

    2014-04-01

    We report a combined dynamic light scattering and neutron spin-echo (NSE) study on vesicles composed of the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphatidylcholine under the influence of varying amounts of perfluorooctanoic acid. We study local lipid bilayer undulations using NSE on time scales up to 200 ns. Similar to the effect evoked by cholesterol, we attribute the observed lipid bilayer stiffening to a condensing effect of the perfluorinated compound on the membrane.

  10. Pediatric aspects of lipid-induced atherogenesis.

    PubMed

    Kannel, W B

    1984-01-01

    There is a need to protect our young from an atherogenic way of life. Atherosclerosis and its precursors have their onset in childhood. Correctable risk factors have been identified that have been shown to exert greater impact early in life than later. Optimal levels of these risk factors for children are being established. The rise in serum lipids, blood pressure, body fat, and blood sugar observed in transition from childhood to adult life is neither inevitable nor desirable. Cardiovascular disease in adults may well begin in childhood with medical trivia such as a tendency to obesity, moderate lipid aberrations, blood pressure elevation, lack of exercise, and the cigarette habit. Recent evidence continues to emphasize blood lipids in atherogenesis. A large amount of cholesterol in the high density lipid (HDL) fraction is protective while the cholesterol in the low density lipid (LDL) is atherogenic. Optimal total cholesterol/HDL cholesterol ratios are in the vicinity of 3.5, corresponding to half the adult average risk in the United States. Worldwide evidence suggests that adult cholesterol values of 180-200 mg/dl are associated with both a low coronary heart disease (CHD) mortality and favorable overall health. In order to achieve this, 140 mg/dl values are needed in children whose blood lipids tend to track into adult life. The rise in serum lipids and deterioration in the LDL/HDL ratio in transition from childhood to adult life seems preventable through hygienic means in childhood when faulty life-styles that promote lipid-induced atherogenesis are conditioned. PMID:6470354

  11. Lipid Microarray Biosensor for Biotoxin Detection.

    SciTech Connect

    Singh, Anup K.; Throckmorton, Daniel J.; Moran-Mirabal, Jose C.; Edel, Joshua B.; Meyer, Grant D.; Craighead, Harold G.

    2006-05-01

    We present the use of micron-sized lipid domains, patterned onto planar substrates and within microfluidic channels, to assay the binding of bacterial toxins via total internal reflection fluorescence microscopy (TIRFM). The lipid domains were patterned using a polymer lift-off technique and consisted of ganglioside-populated DSPC:cholesterol supported lipid bilayers (SLBs). Lipid patterns were formed on the substrates by vesicle fusion followed by polymer lift-off, which revealed micron-sized SLBs containing either ganglioside GT1b or GM1. The ganglioside-populated SLB arrays were then exposed to either Cholera toxin subunit B (CTB) or Tetanus toxin fragment C (TTC). Binding was assayed on planar substrates by TIRFM down to 1 nM concentration for CTB and 100 nM for TTC. Apparent binding constants extracted from three different models applied to the binding curves suggest that binding of a protein to a lipid-based receptor is strongly affected by the lipid composition of the SLB and by the substrate on which the bilayer is formed. Patterning of SLBs inside microfluidic channels also allowed the preparation of lipid domains with different compositions on a single device. Arrays within microfluidic channels were used to achieve segregation and selective binding from a binary mixture of the toxin fragments in one device. The binding and segregation within the microfluidic channels was assayed with epifluorescence as proof of concept. We propose that the method used for patterning the lipid microarrays on planar substrates and within microfluidic channels can be easily adapted to proteins or nucleic acids and can be used for biosensor applications and cell stimulation assays under different flow conditions. KEYWORDS. Microarray, ganglioside, polymer lift-off, cholera toxin, tetanus toxin, TIRFM, binding constant.4

  12. Rapid modification of retroviruses using lipid conjugates

    NASA Astrophysics Data System (ADS)

    Mukherjee, Nimisha G.; Lyon, L. Andrew; LeDoux, Joseph M.

    2009-02-01

    Methods are needed to manipulate natural nanoparticles. Viruses are particularly interesting because they can act as therapeutic cellular delivery agents. Here we examine a new method for rapidly modifying retroviruses that uses lipid conjugates composed of a lipid anchor (1,2-distearoyl-sn-glycero-3-phosphoethanolamine), a polyethylene glycol chain, and biotin. The conjugates rapidly and stably modified retroviruses and enabled them to bind streptavidin. The implication of this work for modifying viruses for gene therapy and vaccination protocols is discussed.

  13. Polymer Diffusion in Lipid Membranes

    NASA Astrophysics Data System (ADS)

    Prasad, Ashok

    2005-03-01

    Motivated by experiments on fluorescently labeled DNA molecules on a supported lipid bilayer, we have examined theoretically diffusion of polymers in two dimensions. The key experimental finding we focus on is the scaling of the diffusion constant of the center of mass, D˜1/N. This implies that no effective hydrodynamic coupling exists between the diffusing DNA segments in the membrane. We construct our theoretical model using the phenomenological hydrodynamic model of supported membranes proposed by Evans and Sackmann. Our model is based on the pre-averaged Oseen tensor, and is similar to the model of Komura and Seki, but elaborated and extended to take explicit account of self-avoidance. We find that the 1/N scaling of D can be understood as a consequence of membrane hydrodynamics in the presence of a supporting surface. Further experimental consequences of the model, in particular the diffusion constant for DNA in free standing membranes, will also be discussed. This work was supported by the NSF through grants DMR-9984471 and DMR-0403997. JK is a Cottrell Scholar of Research Corporation.

  14. Mannosylerythritol lipids: production and applications.

    PubMed

    Morita, Tomotake; Fukuoka, Tokuma; Imura, Tomohiro; Kitamoto, Dai

    2015-01-01

    Mannosylerythritol lipids (MELs) are a glycolipid class of biosurfactants produced by a variety yeast and fungal strains that exhibit excellent interfacial and biochemical properties. MEL-producing fungi were identified using an efficient screening method for the glycolipid production and taxonomical classification on the basis of ribosomal RNA sequences. MEL production is limited primarily to the genus Pseudozyma, with significant variability among the MEL structures produced by each species. Outside of Pseudozyma, one recently isolated strain, Ustilago scitaminea, has been shown to exhibit abundant MEL-B production from sugarcane juice. Structural analyses of these compounds suggest a role for MELs in numerous cosmetic applications. MELs act as effective topical moisturizers and can repair damaged hair. Furthermore, these compounds have been shown to exhibit both protective and healing activities, to activate fibroblasts and papilla cells, and to act as natural antioxidants. In this review, we provide a brief summary of MEL research over the past few decades, focusing on the identification of MEL-producing fungi, the structural characterization of MELs, the use of alternative compounds as a primary carbon source, and the use of these compounds in cosmetic applications. PMID:25748373

  15. Hypersaline Microbial Mat Lipid Biomarkers

    NASA Technical Reports Server (NTRS)

    Jahnke, Linda L.; Embaye, Tsegereda; Turk, Kendra A.; Summons, Roger E.

    2002-01-01

    Lipid biomarkers and compound specific isotopic abundances are powerful tools for studies of contemporary microbial ecosystems. Knowledge of the relationship of biomarkers to microbial physiology and community structure creates important links for understanding the nature of early organisms and paleoenvironments. Our recent work has focused on the hypersaline microbial mats in evaporation ponds at Guerrero Negro, Baja California Sur, Mexico. Specific biomarkers for diatoms, cyanobacteria, archaea, green nonsulfur (GNS), sulfate reducing, sulfur oxidizing and methanotrophic bacteria have been identified. Analyses of the ester-bound fatty acids indicate a highly diverse microbial community, dominated by photosynthetic organisms at the surface. The delta C-13 of cyanobacterial biomarkers such as the monomethylalkanes and hopanoids are consistent with the delta C-13 measured for bulk mat (-10%o), while a GNS biomarker, wax esters (WXE), suggests a more depleted delta C-13 for GNS biomass (-16%o). This isotopic relationship is different than that observed in mats at Octopus Spring, Yellowstone National Park (YSNP) where GNS appear to grow photoheterotrophic ally. WXE abundance, while relatively low, is most pronounced in an anaerobic zone just below the cyanobacterial layer. The WXE isotope composition at GN suggests that these bacteria utilize photoautotrophy incorporating dissolved inorganic carbon (DIC) via the 3-hydroxypropionate pathway using H2S or H2.

  16. Spastin Binds to Lipid Droplets and Affects Lipid Metabolism

    PubMed Central

    Papadopoulos, Chrisovalantis; Orso, Genny; Mancuso, Giuseppe; Herholz, Marija; Gumeni, Sentiljana; Tadepalle, Nimesha; Jüngst, Christian; Tzschichholz, Anne; Schauss, Astrid; Höning, Stefan; Trifunovic, Aleksandra; Daga, Andrea; Rugarli, Elena I.

    2015-01-01

    Mutations in SPAST, encoding spastin, are the most common cause of autosomal dominant hereditary spastic paraplegia (HSP). HSP is characterized by weakness and spasticity of the lower limbs, owing to progressive retrograde degeneration of the long corticospinal axons. Spastin is a conserved microtubule (MT)-severing protein, involved in processes requiring rearrangement of the cytoskeleton in concert to membrane remodeling, such as neurite branching, axonal growth, midbody abscission, and endosome tubulation. Two isoforms of spastin are synthesized from alternative initiation codons (M1 and M87). We now show that spastin-M1 can sort from the endoplasmic reticulum (ER) to pre- and mature lipid droplets (LDs). A hydrophobic motif comprised of amino acids 57 through 86 of spastin was sufficient to direct a reporter protein to LDs, while mutation of arginine 65 to glycine abolished LD targeting. Increased levels of spastin-M1 expression reduced the number but increased the size of LDs. Expression of a mutant unable to bind and sever MTs caused clustering of LDs. Consistent with these findings, ubiquitous overexpression of Dspastin in Drosophila led to bigger and less numerous LDs in the fat bodies and increased triacylglycerol levels. In contrast, Dspastin overexpression increased LD number when expressed specifically in skeletal muscles or nerves. Downregulation of Dspastin and expression of a dominant-negative variant decreased LD number in Drosophila nerves, skeletal muscle and fat bodies, and reduced triacylglycerol levels in the larvae. Moreover, we found reduced amount of fat stores in intestinal cells of worms in which the spas-1 homologue was either depleted by RNA interference or deleted. Taken together, our data uncovers an evolutionarily conserved role of spastin as a positive regulator of LD metabolism and open up the possibility that dysfunction of LDs in axons may contribute to the pathogenesis of HSP. PMID:25875445

  17. Spastin binds to lipid droplets and affects lipid metabolism.

    PubMed

    Papadopoulos, Chrisovalantis; Orso, Genny; Mancuso, Giuseppe; Herholz, Marija; Gumeni, Sentiljana; Tadepalle, Nimesha; Jüngst, Christian; Tzschichholz, Anne; Schauss, Astrid; Höning, Stefan; Trifunovic, Aleksandra; Daga, Andrea; Rugarli, Elena I

    2015-04-01

    Mutations in SPAST, encoding spastin, are the most common cause of autosomal dominant hereditary spastic paraplegia (HSP). HSP is characterized by weakness and spasticity of the lower limbs, owing to progressive retrograde degeneration of the long corticospinal axons. Spastin is a conserved microtubule (MT)-severing protein, involved in processes requiring rearrangement of the cytoskeleton in concert to membrane remodeling, such as neurite branching, axonal growth, midbody abscission, and endosome tubulation. Two isoforms of spastin are synthesized from alternative initiation codons (M1 and M87). We now show that spastin-M1 can sort from the endoplasmic reticulum (ER) to pre- and mature lipid droplets (LDs). A hydrophobic motif comprised of amino acids 57 through 86 of spastin was sufficient to direct a reporter protein to LDs, while mutation of arginine 65 to glycine abolished LD targeting. Increased levels of spastin-M1 expression reduced the number but increased the size of LDs. Expression of a mutant unable to bind and sever MTs caused clustering of LDs. Consistent with these findings, ubiquitous overexpression of Dspastin in Drosophila led to bigger and less numerous LDs in the fat bodies and increased triacylglycerol levels. In contrast, Dspastin overexpression increased LD number when expressed specifically in skeletal muscles or nerves. Downregulation of Dspastin and expression of a dominant-negative variant decreased LD number in Drosophila nerves, skeletal muscle and fat bodies, and reduced triacylglycerol levels in the larvae. Moreover, we found reduced amount of fat stores in intestinal cells of worms in which the spas-1 homologue was either depleted by RNA interference or deleted. Taken together, our data uncovers an evolutionarily conserved role of spastin as a positive regulator of LD metabolism and open up the possibility that dysfunction of LDs in axons may contribute to the pathogenesis of HSP. PMID:25875445

  18. Mechanical Properties of Nanoscopic Lipid Domains.

    PubMed

    Nickels, Jonathan D; Cheng, Xiaolin; Mostofian, Barmak; Stanley, Christopher; Lindner, Benjamin; Heberle, Frederick A; Perticaroli, Stefania; Feygenson, Mikhail; Egami, Takeshi; Standaert, Robert F; Smith, Jeremy C; Myles, Dean A A; Ohl, Michael; Katsaras, John

    2015-12-23

    The lipid raft hypothesis presents insights into how the cell membrane organizes proteins and lipids to accomplish its many vital functions. Yet basic questions remain about the physical mechanisms that lead to the formation, stability, and size of lipid rafts. As a result, much interest has been generated in the study of systems that contain similar lateral heterogeneities, or domains. In the current work we present an experimental approach that is capable of isolating the bending moduli of lipid domains. This is accomplished using neutron scattering and its unique sensitivity to the isotopes of hydrogen. Combining contrast matching approaches with inelastic neutron scattering, we isolate the bending modulus of ?13 nm diameter domains residing in 60 nm unilamellar vesicles, whose lipid composition mimics the mammalian plasma membrane outer leaflet. Importantly, the bending modulus of the nanoscopic domains differs from the modulus of the continuous phase surrounding them. From additional structural measurements and all-atom simulations, we also determine that nanoscopic domains are in-register across the bilayer leaflets. Taken together, these results inform a number of theoretical models of domain/raft formation and highlight the fact that mismatches in bending modulus must be accounted for when explaining the emergence of lateral heterogeneities in lipid systems and biological membranes. PMID:26415030

  19. Lipid phosphate phosphatases from Saccharomyces cerevisiae.

    PubMed

    Carman, George M; Wu, Wen-I

    2007-01-01

    DPP1-encoded and LPP1-encoded lipid phosphate phosphatases are integral membrane proteins in the yeast Saccharomyces cerevisiae. They catalyze the Mg(2+)-independent dephosphorylation of bioactive lipid phosphate molecules such as diacylglycerol pyrophosphate and phosphatidate. These enzymes possess a three-domain lipid phosphatase motif that is localized to the hydrophilic surface of the membrane. The lipid phosphate phosphatase activities of DPP1-encoded and LPP1-encoded enzymes are measured by following the release of water-soluble radioactive inorganic phosphate from chloroform-soluble radioactive lipid phosphate substrate following a chloroform/methanol/water phase partition. The DPP1-encoded enzyme, commonly referred to as diacylglycerol pyrophosphate phosphatase, is purified from wild-type S. cerevisiae membranes by detergent solubilization with Triton X-100 followed by chromatography with DEAE-cellulose (DE53), Affi-Gel blue, hydroxylapatite, and Mono Q. The purification scheme yields an essentially homogeneous enzyme preparation that is stable for several years upon storage at -80 degrees . The properties of the DPP1-encoded and LPP1-encoded lipid phosphate phosphatase enzymes are summarized. PMID:17954255

  20. Persistence of virus lipid signatures upon silicification

    NASA Astrophysics Data System (ADS)

    Kyle, J.; Jahnke, L. L.; Stedman, K. M.

    2011-12-01

    To date there is no known evidence of viruses within the rock record. Their small size and absence of a metabolism has led to the hypothesis that they lack unique biological signatures, and the potential to become preserved. Biosignature research relevant to early Earth has focused on prokaryotic communities; however, the most abundant member of modern ecosystems, viruses, have been ignored. In order to establish a baseline for research on virus biosignatures, we have initiated laboratory research on known lipid-containing viruses. PRD1 is a lipid-containing virus that infects and replicates in Salmonella typhimurium LT2. PRD1 is a 65 nm spherical virus with an internal lipid membrane, which is a few nanometers thick. When the PRD1 virus stock was mixed with a 400 ppm SiO2 (final concentration) solution and incubated for six months. Fourier Transform Infrared Spectroscopy and lipid analysis using gas chromatography revealed that the virus lipids were still detectable despite complete removal of dissolved silica. Free fatty acids were also detected. Titers of infectious PRD1 viruses after six months in the presence of silica decreased 40 times more than without silica. Though virus biosignature research is in its incipient stages, the data suggest that virus lipid signatures are preserved under laboratory conditions and may offer the potential for contribution to the organic geochemical record.

  1. Bending and Puncturing the Influenza Lipid Envelope

    PubMed Central

    Li, Sai; Eghiaian, Frederic; Sieben, Christian; Herrmann, Andreas; Schaap, Iwan A.T.

    2011-01-01

    Lysosomes, enveloped viruses, as well as synaptic and secretory vesicles are all examples of natural nanocontainers (diameter ? 100 nm) which specifically rely on their lipid bilayer to protect and exchange their contents with the cell. We have applied methods primarily based on atomic force microscopy and finite element modeling that allow precise investigation of the mechanical properties of the influenza virus lipid envelope. The mechanical properties of small, spherical vesicles made from PR8 influenza lipids were probed by an atomic force microscopy tip applying forces up to 0.2 nN, which led to an elastic deformation up to 20%, on average. The liposome deformation was modeled using finite element methods to extract the lipid bilayer elastic properties. We found that influenza liposomes were softer than what would be expected for a gel phase bilayer and highly deformable: Consistent with previous suggestion that influenza lipids do not undergo a major phase transition, we observe that the stiffness of influenza liposomes increases gradually and weakly (within one order of magnitude) with temperature. Surprisingly, influenza liposomes were, in most cases, able to withstand wall-to-wall deformation, and forces >1 nN were generally required to puncture the influenza envelope, which is similar to viral protein shells. Hence, the choice of a highly flexible lipid envelope may provide as efficient a protection for a viral genome as a stiff protein shell. PMID:21281578

  2. Lipid-based formulations of amphotericin B.

    PubMed

    Veerareddy, Prabhakar R; Vobalaboina, Venkateswarlu

    2004-02-01

    Amphotericin B remains the drug of choice for the treatment of invasive fungal infections and visceral leishmaniasis. However, both the dose-dependent nephrotoxicity and the low response rates (10-80%) associated with amphotericin B limit its clinical use. The first marketed formulation of amphotericin B with deoxycholate, Fungizone, remains the "gold standard" in spite of its renal toxicity. Several investigations have been made to reduce the nephrotoxicity of amphotericin B by formulation strategies. Lipid-based formulations of amphotericin B were found to reduce toxicity and to increase tolerance and therapeutic efficacy. Three lipid formulations are now available in most countries: liposomal amphotericin B (AmBisome), amphotericin B lipid complex and amphotericin B colloidal dispersion. Amphotericin B colloidal dispersion was less nephrotoxic, but immediate reactions to this formulation were as frequent and severe as those to amphotericin B. Amphotericin B lipid complex appeared to be as effective as amphotericin B, with improved general and renal tolerability. Several comparative studies have confirmed that AmBisome has similar or superior efficacy relative to amphotericin B in various fungal infections, in visceral leishmaniasis and also in the empirical treatment of febrile neutropenia. Renal and general tolerability is excellent. A significant drawback to the newer, less toxic, commercial lipid-based formulations is their cost. There is a need to develop more affordable lipid-based formulations of amphotericin B. PMID:15045035

  3. Interaction of C(60) fullerene with lipids.

    PubMed

    Cataldo, Franco

    2010-06-01

    Unsaturated lipids when exposed to air at room temperature undergo a slow autoxidation. When fullerene C(60) was dissolved in selected lipids (ethyl oleate, ethyl linoleate, linseed oil and castor oil) the spectrophotometric analysis shows that the oxidation is concentrated to C(60) which is converted to an epoxide C(60)O. Thus, fullerene C(60) displays antioxidant activity not only when dissolved in unsaturated lipids but also, more generally, when dissolved in unsaturated solvents subjected to autoxidation like, for example, in cyclohexene. The behaviour of C(60) in ethyl oleate has been compared with that of the known antioxidant TMPPD (N,N',N,N,'-tetramethyl-p-phenylenediamine) in ethyl oleate. The mechanism of the antioxidant action of C(60) in lipids has been proposed. The kinetics of C(60) oxidation in lipids was determined spectrophotometrically both at room temperature in the dark and under UV irradiation. The oxidized products derived from C(60) photo-oxidation in lipids have been identified. PMID:20338159

  4. Lipids, curvature, and nano-medicine*

    PubMed Central

    Mouritsen, Ole G

    2011-01-01

    The physical properties of the lamellar lipid-bilayer component of biological membranes are controlled by a host of thermodynamic forces leading to overall tensionless bilayers with a conspicuous lateral pressure profile and build-in curvature-stress instabilities that may be released locally or globally in terms of morphological changes. In particular, the average molecular shape and the propensity of the different lipid and protein species for forming non-lamellar and curved structures are a source of structural transitions and control of biological function. The effects of different lipids, sterols, and proteins on membrane structure are discussed and it is shown how one can take advantage of the curvature-stress modulations brought about by specific molecular agents, such as fatty acids, lysolipids, and other amphiphilic solutes, to construct intelligent drug-delivery systems that function by enzymatic triggering via curvature. Practical applications: The simple concept of lipid molecular shape and how it impacts on the structure of lipid aggregates, in particular the curvature and curvature stress in lipid bilayers and liposomes, can be exploited to construct liposome-based drug-delivery systems, e.g., for use as nano-medicine in cancer therapy. Non-lamellar-forming lysolipids and fatty acids, some of which may be designed to be prodrugs, can be created by phospholipase action in diseased tissues thereby providing for targeted drug release and proliferation of molecular entities with conical shape that break down the permeability barrier of the target cells and may hence enhance efficacy. PMID:22164124

  5. RHODOPSIN-LIPID INTERACTIONS STUDIED BY NMR

    PubMed Central

    Soubias, Olivier; Gawrisch, Klaus

    2012-01-01

    The biophysical properties of the lipid matrix are known to influence function of integral membrane proteins. We report on a sample preparation method for reconstitution of membrane proteins which uses porous anodic aluminum oxide (AAO) filters with 200 nm-wide pores of high density. The substrate permits formation of tubular, single membranes that line the inner surface of pores. One square centimeter of filter with a thickness of 60 ?m yields on the order of 500 cm2 of solid-supported single bilayer surface, sufficient for NMR studies. The tubular bilayers are free of detergent, fully hydrated and accessible for ligands from one side of the membrane. The use of AAO filters greatly improves reproducibility of the reconstitution process such that the influence of protein on lipid order parameters can be studied with high resolution. As an example, results for the G protein-coupled receptor of class A, bovine rhodopsin, are shown. By 2H NMR order parameter measurements it is detected that rhodopsin insertion elastically deforms membranes near the protein. Furthermore, by 1H saturation-transfer NMR under conditions of magic-angle spinning (MAS), we demonstrate detection of preferences in interactions of rhodopsin with particular lipid species. It is assumed that function of integral membrane proteins depends on both protein-induced elastic deformations of the lipid matrix and preferences for interaction of the protein with particular lipid species in the first layer of lipids surrounding the protein. PMID:23374188

  6. Microalgal lipids biochemistry and biotechnological perspectives.

    PubMed

    Bellou, Stamatia; Baeshen, Mohammed N; Elazzazy, Ahmed M; Aggeli, Dimitra; Sayegh, Fotoon; Aggelis, George

    2014-12-01

    In the last few years, there has been an intense interest in using microalgal lipids in food, chemical and pharmaceutical industries and cosmetology, while a noteworthy research has been performed focusing on all aspects of microalgal lipid production. This includes basic research on the pathways of solar energy conversion and on lipid biosynthesis and catabolism, and applied research dealing with the various biological and technical bottlenecks of the lipid production process. In here, we review the current knowledge in microalgal lipids with respect to their metabolism and various biotechnological applications, and we discuss potential future perspectives. The committing step in fatty acid biosynthesis is the carboxylation of acetyl-CoA to form malonyl-CoA that is then introduced in the fatty acid synthesis cycle leading to the formation of palmitic and stearic acids. Oleic acid may also be synthesized after stearic acid desaturation while further conversions of the fatty acids (i.e. desaturations, elongations) occur after their esterification with structural lipids of both plastids and the endoplasmic reticulum. The aliphatic chains are also used as building blocks for structuring storage acylglycerols via the Kennedy pathway. Current research, aiming to enhance lipogenesis in the microalgal cell, is focusing on over-expressing key-enzymes involved in the earlier steps of the pathway of fatty acid synthesis. A complementary plan would be the repression of lipid catabolism by down-regulating acylglycerol hydrolysis and/or ?-oxidation. The tendency of oleaginous microalgae to synthesize, apart from lipids, significant amounts of other energy-rich compounds such as sugars, in processes competitive to lipogenesis, deserves attention since the lipid yield may be considerably increased by blocking competitive metabolic pathways. The majority of microalgal production occurs in outdoor cultivation and for this reason biotechnological applications face some difficulties. Therefore, algal production systems need to be improved and harvesting systems need to be more effective in order for their industrial applications to become more competitive and economically viable. Besides, a reduction of the production cost of microalgal lipids can be achieved by combining lipid production with other commercial applications. The combined production of bioactive products and lipids, when possible, can support the commercial viability of both processes. Hydrophobic compounds can be extracted simultaneously with lipids and then purified, while hydrophilic compounds such as proteins and sugars may be extracted from the defatted biomass. The microalgae also have applications in environmental biotechnology since they can be used for bioremediation of wastewater and to monitor environmental toxicants. Algal biomass produced during wastewater treatment may be further valorized in the biofuel manufacture. It is anticipated that the high microalgal lipid potential will force research towards finding effective ways to manipulate biochemical pathways involved in lipid biosynthesis and towards cost effective algal cultivation and harvesting systems, as well. PMID:25449285

  7. Perilipins: Lipid Droplet Coat Proteins Adapted for Tissue-Specific Energy Storage and Utilization, and Lipid Cytoprotection

    PubMed Central

    Sztalryd, Carole; Kimmel, Alan R.

    2014-01-01

    Cytosolic lipid storage droplets are primary functional organelles that regulate cellular lipid metabolism and homeostasis. Paradoxically, excess lipid stores are linked to both adaptive (fasting and chronic exercise) and mal-adaptive (obesity and related health complications) conditions. Thus, collective metabolic and physiological processes must balance lipid storage and utilization with prevention of lipocytotoxicity and compounding tissue dysfunctions, urging the need to further define the connection of mammalian lipid droplet function and lipid homeostasis. The perilipins are a multi-protein family that targets lipid droplet surfaces and regulates lipid storage and hydrolysis. Study of perilipin functions has provided insight into the physiological roles of cytosolic lipid droplets and their relationship with obesity-related pathologies. Here, we review the current knowledge of the multiple perilipin proteins in regulating tissue-specific lipid droplets and associations with tissue and systemic energetics. PMID:24036367

  8. The Effect of Membrane Lipid Composition on the Formation of Lipid Ultrananodomains.

    PubMed

    Pathak, Priyadarshini; London, Erwin

    2015-10-20

    Some lipid mixtures form membranes containing submicroscopic (nanodomain) ordered lipid domains (rafts). Some of these nanodomains are so small (radius <5 nm) that they cannot be readily detected with Förster resonance energy transfer (FRET)-labeled lipid pairs with large Ro. We define such domains as ultrananodomains. We studied the effect of lipid structure/composition on the formation of ultrananodomains in lipid vesicles using a dual-FRET-pair approach in which only one FRET pair had Ro values that were sufficiently small to detect the ultrananodomains. Using this approach, we measured the temperature dependence of domain and ultrananodomain formation for vesicles composed of various mixtures containing a high-Tm lipid (brain sphingomyelin (SM)) or dipalmitoyl phosphatidylcholine (DPPC)), low-Tm lipid (dioleoylphosphatidylcholine (DOPC) or 1-palmitoyl 2-oleoyl phosphatidylcholine (POPC)), and a lower (28 mol %) or higher (38 mol %) cholesterol concentration. For every lipid combination tested, the thermal stabilities of the ordered domains were similar, in agreement with our prior studies. However, the range of temperatures over which ultrananodomains formed was highly lipid-type dependent. Overall, vesicles that were closest to mammalian plasma membrane in lipid composition (i.e., with brain SM, POPC, and/or higher cholesterol) formed ultrananodomains in preference to larger domains over the widest temperature range. Relative to DPPC, the favorable effect of SM on ultrananodomain formation versus larger domains was especially large. In addition, the favorable effect of a high cholesterol concentration, and of POPC versus DOPC, on the formation of ultrananodomains versus larger domains was greater in vesicles containing SM than in those containing DPPC. We speculate that it is likely that natural mammalian lipids are tuned to maximize the tendency to form ultrananodomains relative to larger domains. The observation that domain size is more sensitive than domain formation to membrane composition has implications for how membrane domain properties may be regulated in vivo. PMID:26488654

  9. Non-enzymatically derived minor lipids found in Escherichia coli lipid extracts

    PubMed Central

    Garrett, Teresa A.; Raetz, Christian R. H.; Son, Jennifer D.; Richardson, Travis D.; Bartling, Craig; Guan, Ziqiang

    2011-01-01

    Electrospray ionization mass spectrometry is a powerful technique to analyze lipid extracts especially for the identification of new lipid metabolites. A hurdle to lipid identification is the presence of solvent contaminants that hinder the identification of low abundance species or covalently modify abundant lipid species. We have identified several non-enzymatically derived minor lipid species in lipid extracts of Escherichia coli, phosphatidylmethanol, ethyl and methyl carbamates of PE and N-succinyl PE were identified in lipid extracts of Escherichia coli. Phosphatidylmethanol (PM) was identified by exact mass measurement and collision induced dissociation tandem mass spectrometry (MS/MS). Extraction in the presence of deuterated methanol leads to a 3 atomic mass unit shift in the [M-H]- ions of PM indicating its formation during extraction. Ethyl and methyl carbamates of PE, also identified by exact mass measurement and MS/MS, are likely to be formed by phosgene, a breakdown product of chloroform. Addition of phosgene to extractions containing synthetic PE significantly increases the levels of PE-MC detected in the lipid extracts by ESI-MS. Extraction in the presence of methylene chloride significantly reduced the levels of these lipid species. N-succinyl PE is formed from reaction of succinyl-CoA with PE during extraction. Interestingly N-succinyl PE can be formed in an aqueous reaction mixture in the absence of added E. coli proteins. This work highlights the reactivity of the amine of PE and emphasizes that careful extraction controls are required to ensure that new minor lipid species identified using mass spectrometry are indeed endogenous lipid metabolites. PMID:21925285

  10. Vesicle trafficking from a lipid perspective: Lipid regulation of exocytosis in Saccharomyces cerevisiae.

    PubMed

    Johansen, Jesper; Ramanathan, Vidhya; Beh, Christopher T

    2012-07-01

    The protein cargo transported by specific types of vesicles largely defines the different secretory trafficking pathways operating within cells. However, mole per mole the most abundant cargo contained within transport vesicles is not protein, but lipid. Taking a "lipid-centric" point-of-view, we examine the importance of lipid signaling, membrane lipid organization and lipid metabolism for vesicle transport during exocytosis in budding yeast. In fact, the essential requirement for some exocytosis regulatory proteins can be bypassed by making simple manipulations of the lipids involved. During polarized exocytosis the sequential steps required to generate post-Golgi vesicles and target them to the plasma membrane (PM) involves the interplay of several types of lipids that are coordinately linked through PI4P metabolism and signaling. In turn, PI4P levels are regulated by PI4P kinases, the Sac1p PI4P phosphatase and the yeast Osh proteins, which are homologs of mammalian oxysterol-binding protein (OSBP). Together these regulators integrate the transitional steps required for vesicle maturation directly through changes in lipid composition and organization. PMID:23181198

  11. Lipid bilayer membrane affinity rationalizes inhibition of lipid peroxidation by a natural lignan antioxidant.

    PubMed

    Podloucká, Pavlína; Berka, Karel; Fabre, Gabin; Paloncýová, Markéta; Duroux, Jean-Luc; Otyepka, Michal; Trouillas, Patrick

    2013-05-01

    Lipid peroxidation is a degenerative oxidative process that modifies the structure of membranes, influencing their biological functions. Lignans, natural polyphenolic antioxidants widely distributed in plants, can prevent this membrane damage by free-radical scavenging. Here, we rationalize the difference in lipid peroxidation inhibition activity of argenteane, a natural dilignan isolated from wild nutmeg, and 3,3'-dimethoxy-1,1'-biphenyl-2,2'-diol, which represents the central part of argenteane responsible for its antioxidant activity. Although both compounds have the same capacity to scavenge free radicals, argenteane is a more active inhibitor of lipid peroxidation. We show that both compounds penetrate into DOPC and PLPC lipid bilayers and adopt similar positions and orientations, which therefore does not explain the difference in their lipid peroxidation inhibition activity. However, free energy profiles indicate that argenteane has a significantly higher affinity to the lipid bilayer, and thus a higher effective concentration to scavenge radicals formed during lipid peroxidation. This finding explains the higher activity of argenteane to inhibit lipid peroxidation. PMID:23560800

  12. Membrane-spanning lipids for an uncompromised monitoring of membrane fusion and intermembrane lipid transfer.

    PubMed

    Schwarzmann, Günter; Breiden, Bernadette; Sandhoff, Konrad

    2015-10-01

    A Förster resonance energy transfer-based fusion and transfer assay was developed to study, in model membranes, protein-mediated membrane fusion and intermembrane lipid transfer of fluorescent sphingolipid analogs. For this assay, it became necessary to apply labeled reporter molecules that are resistant to spontaneous as well as protein-mediated intermembrane transfer. The novelty of this assay is the use of nonextractable fluorescent membrane-spanning bipolar lipids. Starting from the tetraether lipid caldarchaeol, we synthesized fluorescent analogs with fluorophores at both polar ends. In addition, we synthesized radioactive glycosylated caldarchaeols. These labeled lipids were shown to stretch through bilayer membranes rather than to loop within a single lipid layer of liposomes. More important, the membrane-spanning lipids (MSLs) in contrast to phosphoglycerides proved to be nonextractable by proteins. We could show that the GM2 activator protein (GM2AP) is promiscuous with respect to glycero- and sphingolipid transfer. Saposin (Sap) B also transferred sphingolipids albeit with kinetics different from GM2AP. In addition, we could unambiguously show that the recombinant activator protein Sap C x His6 induced membrane fusion rather than intermembrane lipid transfer. These findings showed that these novel MSLs, in contrast with fluorescent phosphoglycerolipids, are well suited for an uncompromised monitoring of membrane fusion and intermembrane lipid transfer. PMID:26269359

  13. Modeling Lipid-Lipid Correlations across a Bilayer Membrane Using the Quasi-chemical Approximation.

    PubMed

    Bossa, Guilherme Volpe; Roth, Joseph; May, Sylvio

    2015-09-15

    Mixed fluid-like lipid membranes exhibit interactions not only among the lipids within a given leaflet but also across the bilayer. The ensuing collective interleaflet coupling of entire membrane domains has been modeled previously using various mean-field approaches. Yet, also on the level of individual lipids have correlations across the bilayer been observed experimentally for binary mixtures of charged/uncharged lipids with mismatching combinations of short and long acyl chain lengths. The present study proposes a lattice gas model to quantify these correlations. To this end, we represent a macroscopically homogeneous lipid bilayer by two coupled two-dimensional lattice gases that we study using the quasi-chemical approximation. We demonstrate that the rationalization of previous experimental results is only possible if besides two-body lipid-lipid interactions within and across the bilayer our model also accounts for an additional multibody interaction mechanism, namely the local hydrophobic height mismatch created by pairing short and long chain lipids together. The robustness of the quasi-chemical approximation is verified by comparison with Monte Carlo simulations. PMID:26302019

  14. Lipid biosynthesis in chloroplast mutants of barley.

    PubMed

    Appelqvist, L A; Boynton, J E; Henningsen, K W; Stumpf, P K; von Wettstein, D

    1968-07-01

    The capacity of leaf slices from light-grown seedlings of wild type barley and 10 xantha mutants at six different gene loci to incorporate acetate-(14)C into various lipids has been investigated. The fatty acid composition of the leaf lipids in these lethal mutants was similar to that of the wild type, but the fatty acid labeling pattern in the individual lipid classes can be drastically altered by these mutations, which affect chloroplast differentiation. A genetic block in chlorophyll synthesis, caused by mutations in the xan-f locus, leads to a repression of the formation of chloroplast membranes and of acetate incorporation into phospho-, sulfo-, and galacto-lipids (the acetate being preferentially channeled into a lipid fraction containing steroids and free fatty acids). Two leucine "auxotrophs" at different loci, which in the absence of leucine in the growth medium produce giant grana and accumulate some chlorophyll, differed considerably in the amount of labeling of their polar lipids during incubation. Leaves of xan-a(11), containing plastids with little chlorophyll, highly disorganized membrane systems, and large bodies with osmiophilic deposits, were nonetheless equal to wild type in their capacity to incorporate acetate-(14)C into phospho-, sulfo-, and galacto-lipids. The mutants at the xan-m locus have plastids with undispersed prolamellar bodies and osmiophilic packages of grana-like membranes associations. Leaf slices of these mutants synthesized considerably more linolenic acid-(14)C, which was incorporated into monogalactosyl diglycerides, than did slices of the wild type. This led to a labeling pattern of the fatty acids in the monogalactolipids which was remarkably similar to their endogenous fatty acid composition. PMID:5725883

  15. A Parameterization of Cholesterol for Mixed Lipid Bilayer Simulation within the Amber Lipid14 Force Field.

    PubMed

    Madej, Benjamin D; Gould, Ian R; Walker, Ross C

    2015-09-24

    The Amber Lipid14 force field is expanded to include cholesterol parameters for all-atom cholesterol and lipid bilayer molecular dynamics simulations. The General Amber and Lipid14 force fields are used as a basis for assigning atom types and basic parameters. A new RESP charge derivation for cholesterol is presented, and tail parameters are adapted from Lipid14 alkane tails. 1,2-Dimyristoyl-sn-glycero-3-phosphocholine (DMPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayers are simulated at a range of cholesterol contents. Experimental bilayer structural properties are compared with bilayer simulations and are found to be in good agreement. With this parameterization, another component of complex membranes is available for molecular dynamics with the Amber Lipid14 force field. PMID:26359797

  16. Chain ordering of hybrid lipids can stabilize domains in saturated/hybrid/cholesterol lipid membranes

    NASA Astrophysics Data System (ADS)

    Yamamoto, T.; Brewster, R.; Safran, S. A.

    2010-07-01

    We use a liquid-crystal model to predict that hybrid lipids (lipids that have one saturated and one unsaturated tail) can stabilize line interfaces between domains in mixed membranes of saturated lipids, hybrid lipids, and cholesterol (SHC membranes). The model predicts the phase separation of SHC membranes with both parabolic and loop binodals depending on the cholesterol concentration, modeled via an effective pressure. In some cases, the hybrid lipids can reduce the line tension to zero in SHC membranes at temperatures that approach the critical temperature as the pressure is increased. The differences in the hybrid saturated tail conformational order in bulk and at the interface are responsible for the reduction of the line tension.

  17. Lipids and lipid-based formulations: optimizing the oral delivery of lipophilic drugs.

    PubMed

    Porter, Christopher J H; Trevaskis, Natalie L; Charman, William N

    2007-03-01

    Highly potent, but poorly water-soluble, drug candidates are common outcomes of contemporary drug discovery programmes and present a number of challenges to drug development - most notably, the issue of reduced systemic exposure after oral administration. However, it is increasingly apparent that formulations containing natural and/or synthetic lipids present a viable means for enhancing the oral bioavailability of some poorly water-soluble, highly lipophilic drugs. This Review details the mechanisms by which lipids and lipidic excipients affect the oral absorption of lipophilic drugs and provides a perspective on the possible future applications of lipid-based delivery systems. Particular emphasis has been placed on the capacity of lipids to enhance drug solubilization in the intestinal milieu, recruit intestinal lymphatic drug transport (and thereby reduce first-pass drug metabolism) and alter enterocyte-based drug transport and disposition. PMID:17330072

  18. Solid Lipid Nanoparticles and Nanostructured Lipid Carriers: Structure, Preparation and Application

    PubMed Central

    Naseri, Neda; Valizadeh, Hadi; Zakeri-Milani, Parvin

    2015-01-01

    Lipid nanoparticles (LNPs) have attracted special interest during last few decades. Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) are two major types of Lipid-based nanoparticles. SLNs were developed to overcome the limitations of other colloidal carriers, such as emulsions, liposomes and polymeric nanoparticles because they have advantages like good release profile and targeted drug delivery with excellent physical stability. In the next generation of the lipid nanoparticle, NLCs are modified SLNs which improve the stability and capacity loading. Three structural models of NLCs have been proposed. These LNPs have potential applications in drug delivery field, research, cosmetics, clinical medicine, etc. This article focuses on features, structure and innovation of LNPs and presents a wide discussion about preparation methods, advantages, disadvantages and applications of LNPs by focusing on SLNs and NLCs. PMID:26504751

  19. Shape Transformations of Lipid Vesicles by Insertion of Bulky-Head Lipids

    PubMed Central

    Tsuda, Soichiro; Sakakura, Tatsuya; Fujii, Satoshi; Suzuki, Hiroaki; Yomo, Tetsuya

    2015-01-01

    Lipid vesicles, in particular Giant Unilamellar Vesicles (GUVs), have been increasingly important as compartments of artificial cells to reconstruct living cell-like systems in a bottom-up fashion. Here, we report shape transformations of lipid vesicles induced by polyethylene glycol-lipid conjugate (PEG lipids). Statistical analysis of deformed vesicle shapes revealed that shapes vesicles tend to deform into depended on the concentration of the PEG lipids. When compared with theoretically simulated vesicle shapes, those shapes were found to be more energetically favorable, with lower membrane bending energies than other shapes. This result suggests that the vesicle shape transformations can be controlled by externally added membrane molecules, which can serve as a potential method to control the replications of artificial cells. PMID:26176953

  20. Dividing Cells Regulate Their Lipid Composition and Localization

    PubMed Central

    Atilla-Gokcumen, G. Ekin; Muro, Eleonora; Relat-Goberna, Josep; Sasse, Sofia; Bedigian, Anne; Coughlin, Margaret L.; Garcia-Manyes, Sergi; Eggert, Ulrike S.

    2014-01-01

    Summary Although massive membrane rearrangements occur during cell division, little is known about specific roles that lipids might play in this process. We report that the lipidome changes with the cell cycle. LC-MS-based lipid profiling shows that 11 lipids with specific chemical structures accumulate in dividing cells. Using AFM, we demonstrate differences in the mechanical properties of live dividing cells and their isolated lipids relative to nondividing cells. In parallel, systematic RNAi knockdown of lipid biosynthetic enzymes identified enzymes required for division, which highly correlated with lipids accumulated in dividing cells. We show that cells specifically regulate the localization of lipids to midbodies, membrane-based structures where cleavage occurs. We conclude that cells actively regulate and modulate their lipid composition and localization during division, with both signaling and structural roles likely. This work has broader implications for the active and sustained participation of lipids in basic biology. PMID:24462247

  1. Surface features of the lipid droplet mediate perilipin 2 localization

    PubMed Central

    Sletten, Arthur; Seline, Alison; Rudd, Andrew; Logsdon, Michelle; Listenberger, Laura L.

    2014-01-01

    All eukaryotic organisms store excess lipid in intracellular lipid droplets. These dynamic structures are associated with and regulated by numerous proteins. Perilipin 2, an abundant protein on most lipid droplets, promotes neutral lipid accumulation in lipid droplets. However, the mechanism by which perilipin 2 binds to and remains anchored on the lipid droplet surface is unknown. Here we identify features of the lipid droplet surface that influence perilipin 2 localization. We show that perilipin 2 binding to the lipid droplet surface requires both hydrophobic and electrostatic interactions. Reagents that disrupt these interactions also decrease binding. Moreover, perilipin 2 binding does not depend on other lipid droplet-associated proteins but is influenced by the lipid composition of the surface. Perilipin 2 binds to synthetic vesicles composed of dioleoylphosphatidylcholine, a phospholipid with unsaturated acyl chains. Decreasing the temperature of the binding reaction, or introducing phospholipids with saturated acyl chains, decreases binding. We therefore demonstrate a role for surface lipids and acyl chain packing in perilipin 2 binding to lipid droplets. The ability of the lipid droplet phospholipid composition to impact protein binding may link changes in nutrient availability to lipid droplet homeostasis. PMID:25172666

  2. Interaction of triclosan with eukaryotic membrane lipids.

    PubMed

    Lygre, Henning; Moe, Grete; Skålevik, Rita; Holmsen, Holm

    2003-06-01

    The possibility that triclosan and PVM/MA (polyvinylmethyl ether/maleic acid) copolymer, additives to dentrifrices, could interact with eukaryotic membrane lipids was studied by two methods: first, by determining the pressure/molecular area isotherms at 37 degrees C of glycerophospholipid monolayers, using the Langmuir technique; and second, by phase-transition parameters in liposomes of the same lipids, using differential scanning calorimetry (DSC). Triclosan interacted, in a concentration-independent manner, with monolayers of saturated phosphatidylcholines (PC; i.e. markers of the outer membrane leaflet of eukaryotic cells). Triclosan and PVM/MA copolymer mixtures were shown to clearly interact in a concentration-dependent manner with PC. Triclosan was found to interact with liposomes of saturated and unsaturated phosphatidylcholines and phosphatidylserines (PS; i.e. markers of the inner membrane leaflet of eukaryotic cells), and saturated ethanolamines (PE; i.e. markers of the inner membrane leaflet of eukaryotic cells), resulting in a decrease of the lipid melting temperature (Tm). PVM/MA copolymer changed the Tm of PS, PC, and PE in different manners. By adding PVM/MA or triclosan-PVM/MA copolymer mixtures to 1-stearoyl-2-oleoyl-sn-glycero-3-phosphoserine (SOPS) no lipid transitions were detected. A biphasic change of the PC transition temperature resulted when triclosan or triclosan PVM/MA copolymer mixtures were added, indicating domain formation and change of the lipid polymorphism. PMID:12786952

  3. Intravenous Lipids for Preterm Infants: A Review

    PubMed Central

    Salama, Ghassan SA; Kaabneh, Mahmmoud AF; Almasaeed, Mai N; Alquran, Mohammad IA

    2015-01-01

    Extremely low birth weight infants (ELBW) are born at a time when the fetus is undergoing rapid intrauterine brain and body growth. Continuation of this growth in the first several weeks postnatally during the time these infants are on ventilator support and receiving critical care is often a challenge. These infants are usually highly stressed and at risk for catabolism. Parenteral nutrition is needed in these infants because most cannot meet the majority of their nutritional needs using the enteral route. Despite adoption of a more aggressive approach with amino acid infusions, there still appears to be a reluctance to use early intravenous lipids. This is based on several dogmas that suggest that lipid infusions may be associated with the development or exacerbation of lung disease, displace bilirubin from albumin, exacerbate sepsis, and cause CNS injury and thrombocytopena. Several recent reviews have focused on intravenous nutrition for premature neonate, but very little exists that provides a comprehensive review of intravenous lipid for very low birth and other critically ill neonates. Here, we would like to provide a brief basic overview, of lipid biochemistry and metabolism of lipids, especially as they pertain to the preterm infant, discuss the origin of some of the current clinical practices, and provide a review of the literature, that can be used as a basis for revising clinical care, and provide some clarity in this controversial area, where clinical care is often based more on tradition and dogma than science. PMID:25698888

  4. Relation between optimism and lipids in midlife.

    PubMed

    Boehm, Julia K; Williams, David R; Rimm, Eric B; Ryff, Carol; Kubzansky, Laura D

    2013-05-15

    The present research examined optimism's relation with total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides. The hypothesis that optimism is associated with a healthier lipid profile was tested. The participants were 990 mostly white men and women from the Midlife in the United States study, who were, on average, 55.1 years old. Optimism was assessed by self-report using the Life Orientation Test. A fasting blood sample was used to assess the serum lipid levels. Linear and logistic regression models examined the cross-sectional association between optimism and lipid levels, accounting for covariates such as demographic characteristics (e.g., education) and health status (e.g., chronic medical conditions). After adjusting for covariates, the results suggested that greater optimism was associated with greater high-density lipoprotein cholesterol and lower triglycerides. Optimism was not associated with low-density lipoprotein or total cholesterol. The findings were robust to a variety of modeling strategies that considered the effect of treatment of cholesterol problems. The results also indicated that diet and body mass index might link optimism with lipids. In conclusion, this is the first study to suggest that optimism is associated with a healthy lipid profile; moreover, these associations can be explained, in part, by the presence of healthier behaviors and a lower body mass index. PMID:23433765

  5. Transformation of lipids in activated sludge.

    PubMed

    Dueholm, T E; Andreasen, K H; Nielsen, P H

    2001-01-01

    Transformation of lipids in activated sludge treatment plants is of interest for two reasons: lipids contribute 30-40% of the chemical oxygen demand (COD) in wastewater, and they may stimulate the growth of filamentous microorganisms in nutrient removal activated sludge plants. The transformation of lipids was investigated under aerobic and anoxic conditions by measuring the oxygen and nitrate uptake rates (OUR and NUR). The maximal OUR and NUR of long-chain fatty acid was found to be at the same level as acetate indicating that long-chain fatty acid was as easily consumable. However, the adsorption of long-chain fatty acid to surfaces of sludge flocs made it difficult to determine initial uptake rates of long-chain fatty acids. It was not possible to describe the hydrolysis rate of triacylglyceride by OUR and NUR to long-chain fatty acids because the hydrolysis rate was very slow. For a better description of the processes involved in transformation of lipids, a conceptual model was suggested. The processes in the suggested model were the adsorption/desorption of both triacylglyceride, and long-chain fatty acid onto surfaces of sludge flocs, hydrolysis of triacylglyceride by lipases and the uptake of long-chain fatty acid by bacteria under various conditions. The model can be helpful to structure design and evaluation of activated sludge experiment with lipids. PMID:11379087

  6. Simulation studies of stratum corneum lipid mixtures

    E-print Network

    Chinmay Das; Massimo G. Noro; Peter D. Olmsted

    2009-07-03

    We present atomistic molecular dynamics results for fully hydrated bilayers composed of ceramide NS-24:0, free fatty acid 24:0 and cholesterol, to address the effect of the different components in the stratum corneum (the outermost layer of skin) lipid matrix on its structural properties. Bilayers containing ceramide molecules show higher in-plane density and hence lower rate of passive transport compared to phospholipid bilayers. At physiological temperatures, for all composition ratios explored, the lipids are in a gel phase with ordered lipid tails. However, the large asymmetry in the lengths of the two tails of the ceramide molecule leads to a fluid like environment at the bilayer mid-plane. The lateral pressure profiles show large local variations across the bilayer for pure ceramide or any of the two component mixtures. Close to the skin composition ratio, the lateral pressure fluctuations are greatly suppressed, the ceramide tails from the two leaflets interdigitate significantly, the depression in local density at the inter-leaflet region is lowered, and the bilayer have lowered elastic moduli. This indicates that the observed composition ratio in the stratum corneum lipid layer is responsible for both the good barrier properties and the stability of the lipid structure against mechanical stresses.

  7. Lipid binding proteins from parasitic platyhelminthes

    PubMed Central

    Alvite, Gabriela; Esteves, Adriana

    2012-01-01

    Two main families of lipid binding proteins have been identified in parasitic Platyhelminthes: hydrophobic ligand binding proteins (HLBPs) and fatty acid binding proteins (FABPs). Members of the former family of proteins are specific to the Cestoda class, while FABPs are conserved across a wide range of animal species. Because Platyhelminthes are unable to synthesize their own lipids, these lipid-binding proteins are important molecules in these organisms. HLBPs are a high molecular mass complex of proteins and lipids. They are composed of subunits of low molecular mass proteins and a wide array of lipid molecules ranging from CoA esters to cholesterol. These proteins are excretory-secretory molecules and are key serological tools for diagnosis of diseases caused by cestodes. FABPs are mainly intracellular proteins of low molecular weight. They are also vaccine candidates. Despite that the knowledge of their function is scarce, the differences in their molecular organization, ligand preferences, intra/extracellular localization, evolution, and phylogenetic distribution, suggest that platyhelminths HLBPs and FABPs should play different functions. FABPs might be involved in the removal of fatty acids from the inner surface of the cell membrane and in their subsequent targeting to specific cellular destinations. In contrast, HLBPs might be involved in fatty acid uptake from the host environment. PMID:22988444

  8. Preservation of Microbial Lipids in Geothermal Sinters

    NASA Astrophysics Data System (ADS)

    Kaur, Gurpreet; Mountain, Bruce W.; Hopmans, Ellen C.; Pancost, Richard D.

    2011-04-01

    Lipid biomarkers are widely used to study the earliest life on Earth and have been invoked as potential astrobiological markers, but few studies have assessed their survival and persistence in geothermal settings. Here, we investigate lipid preservation in active and inactive geothermal silica sinters, with ages of up to 900 years, from Champagne Pool, Waiotapu, New Zealand. Analyses revealed a wide range of bacterial biomarkers, including free and bound fatty acids, 1,2-di-O-alkylglycerols (diethers), and various hopanoids. Dominant archaeal lipids include archaeol and glycerol dialkyl glycerol tetraethers (GDGTs). The predominance of generally similar biomarker groups in all sinters suggests a stable microbial community throughout Champagne Pool's history and indicates that incorporated lipids can be well preserved. Moreover, subtle differences in lipid distributions suggest that past changes in environmental conditions can be elucidated. In this case, higher archaeol abundances relative to the bacterial diethers, a greater proportion of cyclic GDGTs, the high average chain length of the bacterial diethers, and greater concentrations of hopanoic acids in the older sinters all suggest hotter conditions at Champagne Pool in the past.

  9. Relation between Optimism and Lipids in Midlife

    PubMed Central

    Boehm, Julia K.; Williams, David R.; Rimm, Eric B.; Ryff, Carol; Kubzansky, Laura D.

    2013-01-01

    This research examined optimism’s relationship with total cholesterol, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, and triglycerides. The hypothesis that optimism is associated with a healthier lipid profile was tested. Participants were 990 mostly white men and women from the Midlife in the United States study who were on average 55.1 years old. Optimism was assessed by self-report with the Life Orientation Test. A fasting blood sample was used to assess serum lipid levels. Linear and logistic regression models examined the cross-sectional association between optimism and lipids accounting for covariates such as demographic characteristics (e.g., education) and health status (e.g., chronic medical conditions). After adjusting for covariates, results suggested that greater optimism was associated with higher HDL cholesterol and lower triglycerides. Optimism was not associated with LDL or total cholesterol. Findings were robust to a variety of modeling strategies that took into consideration the effect of treatment for cholesterol problems. Results further indicated that diet and body mass index may link optimism with lipids. In conclusion, this is the first study to suggest that optimism is associated with a healthy lipid profile; moreover, these associations may be explained, in part, by having healthier behaviors and a lower body mass index. PMID:23433765

  10. Atomistic Monte Carlo Simulation of Lipid Membranes

    PubMed Central

    Wüstner, Daniel; Sklenar, Heinz

    2014-01-01

    Biological membranes are complex assemblies of many different molecules of which analysis demands a variety of experimental and computational approaches. In this article, we explain challenges and advantages of atomistic Monte Carlo (MC) simulation of lipid membranes. We provide an introduction into the various move sets that are implemented in current MC methods for efficient conformational sampling of lipids and other molecules. In the second part, we demonstrate for a concrete example, how an atomistic local-move set can be implemented for MC simulations of phospholipid monomers and bilayer patches. We use our recently devised chain breakage/closure (CBC) local move set in the bond-/torsion angle space with the constant-bond-length approximation (CBLA) for the phospholipid dipalmitoylphosphatidylcholine (DPPC). We demonstrate rapid conformational equilibration for a single DPPC molecule, as assessed by calculation of molecular energies and entropies. We also show transition from a crystalline-like to a fluid DPPC bilayer by the CBC local-move MC method, as indicated by the electron density profile, head group orientation, area per lipid, and whole-lipid displacements. We discuss the potential of local-move MC methods in combination with molecular dynamics simulations, for example, for studying multi-component lipid membranes containing cholesterol. PMID:24469314

  11. Nanosecond Lipid Dynamics in Membranes Containing Cholesterol

    SciTech Connect

    Armstrong, Clare L; Haeussler, Wolfgang; Seydel, Tilo; Katsaras, John; Rheinstadter, Maikel C

    2014-01-01

    Lipid dynamics in the cholesterol-rich (40 mol%) liquid-ordered (lo) phase of dimyristoylphosphatidylcholine membranes were studied using neutron spin-echo and neutron backscattering. Recent theoretical and experimental evidence supports the notion of the liquid-ordered phase in phospholipid membranes as a locally structured liquid, with small ordered domains of a highly dynamic nature in equilibrium with a disordered matrix [S. Meinhardt, R. L. C. Vink and F. Schmid, Proc. Natl. Acad. Sci. U. S. A., 2013, 110(12), 4476 4481, C. L. Armstrong et al., PLoS One, 2013, 8(6), e66162]. This local structure was found to have a pronounced impact on the membranes' dynamical properties. We found that the long-wavelength dynamics in the liquid-ordered phase, associated with the elastic properties of the membranes, were faster by two orders of magnitude as compared to the liquid disordered phase. At the same time, collective nanoscale diffusion was significantly slower. The presence of a soft-mode (a slowing down) in the longwavelength dispersion relationship suggests an upper size limit for the ordered lipid domain of ~220 A. Moreover, from the relaxation rate of the collective lipid diffusion of lipid lipid distances, the lifetime of these domains was estimated to be about 100 nanoseconds.

  12. [Lipid therapy in daily routine].

    PubMed

    Sonntag, F; Schaefer, J R; Gitt, A K; Weizel, A; Jannowitz, C; Karmann, B; Pittrow, D; Bestehorn, K

    2012-10-01

    Patients with increased cardiovascular risk profile are frequently seen in general practice. Comprehensive management of modifiable risk factors, in particular dyslipidemia, is mandatory. Many studies in clinical practice have shown a gap between the recommendations in clinical guidelines and the actual situation. Current data on the management situation of patients with high cardiovascular risk is provided by the prospective registry LIMA. Primary care physicians in 2,387 offices throughout Germany documented 13,924 patients with coronary artery disease (CAD), diabetes mellitus or peripheral arterial disease (PAD). Treatment with simvastatin 40?mg was an inclusion criterion. Physicians documented drug utilization, laboratory values (lipids, blood glucose), blood pressure and clinical events over one year and received feedback about the target value attainment of their patients after data entry. Mean age of the patients was 65.7 years, and 61.6?% were men. CAD was reported in 70.6?%, diabetes mellitus in 58.2?% and PAD in 14.9?%. Most patients (68?%) received simvastatin as monotherapy also after the inclusion visit; 20.6?% of patients received in addition the cholesterol absorption inhibitor (ezetimibe) in the first 6 months, and 23.3?% in the second 6 months. Patients achieved the LDL-cholesterol target value in 31.8?% at entry and 50.0?% after one year. The blood pressure target

  13. N-terminus of seed caleosins is essential for lipid droplet sorting but not for lipid accumulation.

    PubMed

    Purkrtová, Zita; Chardot, Thierry; Froissard, Marine

    2015-08-01

    Caleosin, a calcium-binding protein associated with plant lipid droplets, stimulates lipid accumulation when heterologously expressed in Saccharomyces cerevisiae. Accumulated lipids are stored in cytoplasmic lipid droplets that are stabilised by incorporated caleosin. We designed a set of mutants affecting putative crucial sites for caleosin function and association with lipid droplets, i.e. the N-terminus, the EF-hand motif and the proline-knot motif. We investigated the effect of introduced mutations on caleosin capacity to initiate lipid accumulation and on caleosin sorting within cell as well as on its association with lipid droplets. Our results strongly suggest that the N-terminal domain is essential for proper protein sorting and targeting to lipid droplets but not for enhancing lipid accumulation. PMID:26032334

  14. New insights on glucosylated lipids: metabolism and functions.

    PubMed

    Ishibashi, Yohei; Kohyama-Koganeya, Ayako; Hirabayashi, Yoshio

    2013-09-01

    Ceramide, cholesterol, and phosphatidic acid are major basic structures for cell membrane lipids. These lipids are modified with glucose to generate glucosylceramide (GlcCer), cholesterylglucoside (ChlGlc), and phosphatidylglucoside (PtdGlc), respectively. Glucosylation dramatically changes the functional properties of lipids. For instance, ceramide acts as a strong tumor suppressor that causes apoptosis and cell cycle arrest, while GlcCer has an opposite effect, downregulating ceramide activities. All glucosylated lipids are enriched in lipid rafts or microdomains and play fundamental roles in a variety of cellular processes. In this review, we discuss the biological functions and metabolism of these three glucosylated lipids. PMID:23770033

  15. Lipid exchange and transfer on nanoparticle supported lipid bilayers: effect of defects, ionic strength, and size.

    PubMed

    Drazenovic, Jelena; Ahmed, Selver; Tuzinkiewicz, Nicole-Marie; Wunder, Stephanie L

    2015-01-20

    Lipid exchange/transfer has been compared for zwitterionic 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dimyristoyl-d54-sn-glycero-3-phosphocholine (DMPC) small unilamellar vesicles (SUVs) and for the same lipids on silica (SiO2) nanoparticle supported lipid bilayers (NP-SLBs) as a function of ionic strength, temperature, temperature cycling, and NP size, above the main gel-to-liquid crystal phase transition temperature, Tm, using d- and h-DMPC and DPPC. Increasing ionic strength decreases the exchange kinetics for the SUVs, but more so for the NP-SLBs, due to better packing of the lipids and increased attraction between the lipid and support. When the NP-SLBs (or SUVs) are cycled above and below Tm, the exchange rate increases compared with exchange at the same temperature without cycling, for similar total times, suggesting that defects provide sites for more facile removal and thus exchange of lipids. Defects can occur: (i) at the phase boundaries between coexisting gel and fluid phases at Tm; (ii) in bare regions of exposed SiO2 that form during NP-SLB formation due to mismatched surface areas of lipid and NPs; and (iii) during cycling as the result of changes in area of the lipids at Tm and mismatched thermal expansion coefficient between the lipids and SiO2 support. Exchange rates are faster for NP-SLBs prepared with the nominal amount of lipid required to form a NP-SLB compared with NP-SLBs that have been prepared with excess lipids to minimize SiO2 patches. Nanosystems prepared with equimolar mixtures of NP-SLBs composed of d-DMPC (d(DMPC)-NP-SLB) and SUVs composed of h-DMPC (h(DMPC)-SUV) show that the calorimetric transition of the "donor" h(DMPC)-SUV decreases in intensity without an initial shift in Tm, indicating that the "acceptor" d(DMPC)-NP-SLB can accommodate more lipids, through either further fusion or insertion of lipids into the distal monolayer. Exchange for d/h(DMPC)-NP-SLB is in the order 100 nm SiO2 > 45 nm SiO2 > 5 nm SiO2. PMID:25425021

  16. Endogenous lipids of the earthworm Lumbricus terrestris.

    PubMed

    Albro, P W; Corbett, J T; Schroeder, J L

    1993-01-01

    Earthworms (Lumbricus terrestris) were given [1-14C]-labeled palmitic acid by gavage on days 0 and 3, and sacrificed on day 7. The distribution of label among lipid classes indicated that glycerides, sterol esters, cerebrosides, sulfatides, phosphatidylethanolamine, phosphatidylserine and (or) phosphatidylinositol, phosphatidylcholine, and sphingomyelin turn over in, or are synthesized by, the earthworm. Free fatty acids still had the highest specific radioactivity of any lipid class at the end of the experiment. Incorporation of label into sterol and hydrocarbon fractions was insignificant and there was no detectable label incorporated into gangliosides. Phosphatidylethanolamine apparently turned over quite slowly compared with other lipid classes, while the cerebroside fraction became highly labeled. Elongation of palmitic acid to stearate and oxidation to CO2 occurred extensively, but there was no evidence for desaturation. PMID:8398080

  17. Unconventional membrane lipid biosynthesis in Xanthomonas campestris.

    PubMed

    Aktas, Meriyem; Narberhaus, Franz

    2015-09-01

    All bacteria are surrounded by at least one bilayer membrane mainly composed of phospholipids (PLs). Biosynthesis of the most abundant PLs phosphatidylethanolamine (PE), phosphatidylglycerol (PG) and cardiolipin (CL) is well understood in model bacteria such as Escherichia coli. It recently emerged, however, that the diversity of bacterial membrane lipids is huge and that not yet explored biosynthesis pathways exist, even for the common PLs. A good example is the plant pathogen Xanthomonas campestris pv. campestris. It contains PE, PG and CL as major lipids and small amounts of the N-methylated PE derivatives monomethyl PE and phosphatidylcholine (PC?=?trimethylated PE). Xanthomonas campestris uses a repertoire of canonical and non-canonical enzymes for the synthesis of its membrane lipids. In this minireview, we briefly recapitulate standard pathways and integrate three recently discovered pathways into the overall picture of bacterial membrane biosynthesis. PMID:26119594

  18. Apolipoprotein gene involved in lipid metabolism

    DOEpatents

    Rubin, Edward (Berkeley, CA); Pennacchio, Len A. (Sebastopol, CA)

    2007-07-03

    Methods and materials for studying the effects of a newly identified human gene, APOAV, and the corresponding mouse gene apoAV. The sequences of the genes are given, and transgenic animals which either contain the gene or have the endogenous gene knocked out are described. In addition, single nucleotide polymorphisms (SNPs) in the gene are described and characterized. It is demonstrated that certain SNPs are associated with diseases involving lipids and triglycerides and other metabolic diseases. These SNPs may be used alone or with SNPs from other genes to study individual risk factors. Methods for intervention in lipid diseases, including the screening of drugs to treat lipid-related or diabetic diseases are also disclosed.

  19. LIPID SYNTHESIS, INTRACELLULAR TRANSPORT, STORAGE, AND SECRETION

    PubMed Central

    Stein, Olga; Stein, Yechezkiel

    1967-01-01

    A time sequence study of intracellular movement of labeled lipid in the liver was carried out on fasted and ethanol-treated rats injected with either palmitate-3H or glycerol-3H by electron microscopic radioautography. The elimination of water-soluble lipid precursors during specimen preparation was checked and found to be complete. The labeled lipid product in the tissue was identified as mostly triglyceride. A dehydration procedure was adapted to minimize the loss of lipid during specimen preparation. At 2 min after injection, the earliest time interval studied, both precursors were found to have penetrated the liver cells, and the label was found over both rough and smooth elements of the endoplasmic reticulum, which is the site of glyceride esterification. From 5 min on, in fasted and especially in ethanol-treated rats, the label was seen also over lipid droplets 0.5–2.0 µ in diameter, which represent "storage lipid" (slowly turning over compartment). Mitochondria became labeled mostly at later time intervals after injection. From 10 min on, concentration of label was seen over the Golgi apparatus, containing small osmiophilic particles. Association of label with groups of particles in smooth-surfaced vesicles and vacuoles in and near the Golgi apparatus and in the vicinity of the sinusoidal border was seen, both after palmitate-3H and glycerol-3H. It is proposed that these particles represent lipoproteins which are formed in the endoplasmic reticulum, "processed" in the Golgi apparatus, and transported in vacuoles to the sinusoid surface to be discharged into the circulation. PMID:6039375

  20. A comparative study: the impact of different lipid extraction methods on current microalgal lipid research

    PubMed Central

    2014-01-01

    Microalgae cells have the potential to rapidly accumulate lipids, such as triacylglycerides that contain fatty acids important for high value fatty acids (e.g., EPA and DHA) and/or biodiesel production. However, lipid extraction methods for microalgae cells are not well established, and there is currently no standard extraction method for the determination of the fatty acid content of microalgae. This has caused a few problems in microlagal biofuel research due to the bias derived from different extraction methods. Therefore, this study used several extraction methods for fatty acid analysis on marine microalga Tetraselmis sp. M8, aiming to assess the potential impact of different extractions on current microalgal lipid research. These methods included classical Bligh & Dyer lipid extraction, two other chemical extractions using different solvents and sonication, direct saponification and supercritical CO2 extraction. Soxhlet-based extraction was used to weigh out the importance of solvent polarity in the algal oil extraction. Coupled with GC/MS, a Thermogravimetric Analyser was used to improve the quantification of microalgal lipid extractions. Among these extractions, significant differences were observed in both, extract yield and fatty acid composition. The supercritical extraction technique stood out most for effective extraction of microalgal lipids, especially for long chain unsaturated fatty acids. The results highlight the necessity for comparative analyses of microalgae fatty acids and careful choice and validation of analytical methodology in microalgal lipid research. PMID:24456581

  1. Influences of the Structure of Lipids on Thermal Stability of Lipid Membranes

    NASA Astrophysics Data System (ADS)

    Hai, Nan-Nan; Zhou, Xin; Li, Ming

    2015-08-01

    The binding free energy (BFE) of lipid to lipid bilayer is a critical factor to determine the thermal or mechanical stability of the bilayer. Although the molecular structure of lipids has significant impacts on BFE of the lipid, there lacks a systematic study on this issue. In this paper we use coarse-grained molecular dynamics simulation to investigate this problem for several typical phospholipids. We find that both the tail length and tail unsaturation can significantly affect the BFE of lipids but in opposite way, namely, BFE decreases linearly with increasing length, but increases linearly with addition of unsaturated bonds. Inspired by the specific structure of cholesterol which is a crucial component of biomembrane, we also find that introduction of carbo-ring-like structures to the lipid tail or to the bilayer may greatly enhance the stability of the bilayer. Our simulation also shows that temperature can influence the bilayer stability and this effect can be significant when the bilayer undergoes phase transition. These results may be helpful to the design of liposome or other self-assembled lipid systems. Support by the National Natural Science Foundation of China under Grant Nos. 91027046 and 11105218.

  2. A comparative study: the impact of different lipid extraction methods on current microalgal lipid research.

    PubMed

    Li, Yan; Ghasemi Naghdi, Forough; Garg, Sourabh; Adarme-Vega, Tania Catalina; Thurecht, Kristofer J; Ghafor, Wael Abdul; Tannock, Simon; Schenk, Peer M

    2014-01-01

    Microalgae cells have the potential to rapidly accumulate lipids, such as triacylglycerides that contain fatty acids important for high value fatty acids (e.g., EPA and DHA) and/or biodiesel production. However, lipid extraction methods for microalgae cells are not well established, and there is currently no standard extraction method for the determination of the fatty acid content of microalgae. This has caused a few problems in microlagal biofuel research due to the bias derived from different extraction methods. Therefore, this study used several extraction methods for fatty acid analysis on marine microalga Tetraselmis sp. M8, aiming to assess the potential impact of different extractions on current microalgal lipid research. These methods included classical Bligh & Dyer lipid extraction, two other chemical extractions using different solvents and sonication, direct saponification and supercritical CO? extraction. Soxhlet-based extraction was used to weigh out the importance of solvent polarity in the algal oil extraction. Coupled with GC/MS, a Thermogravimetric Analyser was used to improve the quantification of microalgal lipid extractions. Among these extractions, significant differences were observed in both, extract yield and fatty acid composition. The supercritical extraction technique stood out most for effective extraction of microalgal lipids, especially for long chain unsaturated fatty acids. The results highlight the necessity for comparative analyses of microalgae fatty acids and careful choice and validation of analytical methodology in microalgal lipid research. PMID:24456581

  3. Influence of cationic lipid concentration on properties of lipid–polymer hybrid nanospheres for gene delivery

    PubMed Central

    Bose, Rajendran JC; Arai, Yoshie; Ahn, Jong Chan; Park, Hansoo; Lee, Soo-Hong

    2015-01-01

    Nanoparticles have been widely used for nonviral gene delivery. Recently, cationic hybrid nanoparticles consisting of two different materials were suggested as a promising delivery vehicle. In this study, nanospheres with a poly(d,l-lactic-co-glycolic acid) (PLGA) core and cationic lipid shell were prepared, and the effect of cationic lipid concentrations on the properties of lipid polymer hybrid nanocarriers investigated. Lipid–polymer hybrid nanospheres (LPHNSs) were fabricated by the emulsion-solvent evaporation method using different concentrations of cationic lipids and characterized for size, surface charge, stability, plasmid DNA-binding capacity, cytotoxicity, and transfection efficiency. All LPHNSs had narrow size distribution with positive surface charges (?-potential 52–60 mV), and showed excellent plasmid DNA-binding capacity. In vitro cytotoxicity measurements with HEK293T, HeLa, HaCaT, and HepG2 cells also showed that LPHNSs exhibited less cytotoxicity than conventional transfection agents, such as Lipofectamine and polyethyleneimine–PLGA. As cationic lipid concentrations increased, the particle size of LPHNSs decreased while their ?-potential increased. In addition, the in vitro transfection efficiency of LPHNSs increased as lipid concentration increased. PMID:26379434

  4. Profiling of Yeast Lipids by Shotgun Lipidomics.

    PubMed

    Klose, Christian; Tarasov, Kirill

    2016-01-01

    Lipidomics is a rapidly growing technology for identification and quantification of a variety of cellular lipid molecules. Following the successful development and application of functional genomic technologies in yeast Saccharomyces cerevisiae, we witness a recent expansion of lipidomics applications in this model organism. The applications include detailed characterization of the yeast lipidome as well as screening for perturbed lipid phenotypes across hundreds of yeast gene deletion mutants. In this chapter, we describe sample handling, mass spectrometry, and bioinformatics methods developed for yeast lipidomics studies. PMID:26483029

  5. Lipid Bilayers: Clusters, Domains and Phases

    PubMed Central

    Ackerman, David G.; Feigenson, Gerald W.

    2015-01-01

    In this chapter we discuss the complex mixing behavior of plasma membrane lipids. To do so, we first introduce the plasma membrane and membrane mixtures often used to model its complexity. We then discuss the nature of lipid phase behavior in bilayers and the distinction between these phases and other manifestations of nonrandom mixing found in one-phase mixtures, such as clusters, micelles, and microemulsions. Finally, we demonstrate the applicability of Gibbs phase diagrams to the study of increasingly complex model membrane systems, with a focus on phase coexistence, morphology and their implications for the cell plasma membrane. PMID:25658342

  6. Argon laser treatment of lipid keratopathy.

    PubMed Central

    Marsh, R J

    1988-01-01

    Sixty-three cases of vascularised lipid keratopathy were treated with the argon laser to occlude feeder vessels which had been identified by fluorescein angiography. There was a reduction in extent in 62% and density in 49%. Visual acuity was improved in 48%. Six patients had keratoplasties shortly after treatment, none of which showed graft rejection. Minor complications included temporary haemorrhage into the cornea and iris atrophy. A more serious problem was severe corneal thinning after resorption of lipid. The patients had to be carefully followed up and maintained on a low dose of topical steroid. Images PMID:3228545

  7. Comparing Lipid Membranes in Different Environments

    PubMed Central

    2015-01-01

    When engineering lipid membranes for applications, it is essential to characterize them to avoid artifacts introduced by manipulation and the experimental environment. Wide-angle X-ray scattering is a powerful structural characterization tool for well-ordered lipid systems. It reveals remarkable differences in rotational order parameters for samples prepared in different ways. New data and perspectives are presented here for multilamellar systems that support and extend the characterization work on unilamellar systems that is reported by Watkins et al. in this issue of ACS Nano. PMID:24730729

  8. [Lipids in the diet and atherosclerosis].

    PubMed

    Fauré Nogueras, E

    1990-01-01

    Description of the main metabolic methods of different lipoproteins in relation to transportation of both exogenous lipids and endogenous lipids, with special reference to the regulation of synthesis and the destination of colesterol. An analysis was then made of the influence of dietetic colesterol on the different lipoproteins, and that of fatty acids. An evaluation was made of its possible influence on the pathogeny of the atheroma plate. Finally, an alternative unified diet was proposed as a main dietetic guide, both in prevention and therapy. PMID:2132763

  9. Lipid analysis of a ground sloth coprolite

    NASA Astrophysics Data System (ADS)

    Gill, Fiona L.; Crump, Matthew P.; Schouten, Remmert; Bull, Ian D.

    2009-09-01

    Coprolites can provide detailed information about the nutritional habits and digestive processes of the animals that produced them and may also yield information about the palaeoenvironment in which the animal existed. To test the utility of the lipid biomarker approach to coprolite analysis, lipids were extracted from a coprolite of the Pleistocene ground sloth Nothrotheriops shastensis. Gas chromatography/mass spectrometry results revealed a dominant spiroketal sapogenin component identified, using nuclear magnetic resonance spectroscopy, as epismilagenin. The dominance of epismilagenin is probably due to ingestion of Yucca spp. and Agave spp., which is consistent with previous studies on the diet of this species.

  10. Complex roles of hybrid lipids in the composition, order, and size of lipid membrane domains.

    PubMed

    Hassan-Zadeh, Ebrahim; Baykal-Caglar, Eda; Alwarawrah, Mohammad; Huang, Juyang

    2014-02-11

    Hybrid lipids (HL) are phospholipids with one saturated chain and one unsaturated chain. HL are hypothesized to act as linactants (i.e., 2D surfactants) in cell membranes, reducing line tension and creating nanoscopic lipid domains. Here we compare three hybrid lipids of different chain unsaturation (16:0-18:1PC (POPC), 16:0-18:2PC (PLPC), and 16:0-20:4PC (PAPC)) in their abilities to alter the composition, line tension, order, and compactness of lipid domains. We found that the liquid-ordered (Lo) and liquid-disordered (Ld) lipid domains in PAPC/di18:0PC(DSPC)/cholesterol and PLPC/DSPC/cholesterol mixtures are micrometer-sized, and only the POPC/DSPC/cholesterol system has nanoscopic domains. The results indicate that some HLs with polyunsaturated chains are not linactants, and the monounsaturated POPC displays both properties of weak linactants and "Ld-phase" lipids such as di18:1PC (DOPC). The obtained phase boundaries from giant unilamellar vesicles (GUV) show that both POPC and PLPC partition well in the Lo phases. Our MD simulations reveal that these hybrid lipids decrease the order and compactness of Lo domains. Thus, hybrid lipids distinguish themselves from other lipid groups in this combined "partitioning and loosening" ability, which could explain why the Lo domains of GUVs, which often do not contain HL, are more compact than the raft domains in cell membranes. Our line tension measurement and Monte Carlo simulation both show that even the monounsaturated POPC is a weak linactant with only modest ability to occupy domain boundaries and reduce line tension. A more important property of HLs is that they can reduce physical property differences of Lo and Ld bulk domains, which also reduces line tension at domain boundaries. PMID:24456489

  11. Salt modulates the stability and lipid binding affinity of the adipocyte lipid-binding proteins

    NASA Technical Reports Server (NTRS)

    Schoeffler, Allyn J.; Ruiz, Carmen R.; Joubert, Allison M.; Yang, Xuemei; LiCata, Vince J.

    2003-01-01

    Adipocyte lipid-binding protein (ALBP or aP2) is an intracellular fatty acid-binding protein that is found in adipocytes and macrophages and binds a large variety of intracellular lipids with high affinity. Although intracellular lipids are frequently charged, biochemical studies of lipid-binding proteins and their interactions often focus most heavily on the hydrophobic aspects of these proteins and their interactions. In this study, we have characterized the effects of KCl on the stability and lipid binding properties of ALBP. We find that added salt dramatically stabilizes ALBP, increasing its Delta G of unfolding by 3-5 kcal/mol. At 37 degrees C salt can more than double the stability of the protein. At the same time, salt inhibits the binding of the fluorescent lipid 1-anilinonaphthalene-8-sulfonate (ANS) to the protein and induces direct displacement of the lipid from the protein. Thermodynamic linkage analysis of the salt inhibition of ANS binding shows a nearly 1:1 reciprocal linkage: i.e. one ion is released from ALBP when ANS binds, and vice versa. Kinetic experiments show that salt reduces the rate of association between ANS and ALBP while simultaneously increasing the dissociation rate of ANS from the protein. We depict and discuss the thermodynamic linkages among stability, lipid binding, and salt effects for ALBP, including the use of these linkages to calculate the affinity of ANS for the denatured state of ALBP and its dependence on salt concentration. We also discuss the potential molecular origins and potential intracellular consequences of the demonstrated salt linkages to stability and lipid binding in ALBP.

  12. Supported lipid bilayer nanosystems: stabilization by undulatory-protrusion forces and destabilization by lipid bridging.

    PubMed

    Savarala, Sushma; Monson, Frederick; Ilies, Marc A; Wunder, Stephanie L

    2011-05-17

    Control of the stabilization/destabilization of supported lipid bilayers (SLBs) on nanoparticles is important for promotion of their organized assembly and for their use as delivery vehicles. At the same time, understanding the mechanism of these processes can yield insight into nanoparticle-cell interactions and nanoparticle toxicity. In this study, the suspension/precipitation process of zwitterionic lipid/SiO(2) nanosystems was analyzed as a function of ionic strength and as a function of the ratio of lipid/SiO(2) surface areas, at pH = 7.6. Salt is necessary to induce supported lipid bilayer (SLB) formation for zwitterionic lipids on silica (SiO(2)) (Seantier, B.; Kasemo, B., Influence of Mono- and Divalent Ions on the Formation of Supported Phospholipid Bilayers via Vesicle Adsorption. Langmuir 2009, 25 (10), 5767-5772). However, for zwitterionic SLBs on SiO(2) nanoparticles, addition of salt can cause precipitation of the SLBs, due to electrostatic shielding by both the lipid and the salt and to the suppression of thermal undulation/protrusion repulsive forces for lipids on solid surfaces. At ionic strengths that cause precipitation of SLBs, it was found that addition of excess SUVs, at ratios where there were equal populations of SUVs and SLBs, restored the undulation/protrusion repulsive forces and restabilized the suspensions. We suggest that SUVs separate SLBs in the suspension, as observed by TEM, and that SLB-SLB interactions are replaced by SLB-SUV interactions. Decreasing the relative amount of lipid, to the extent that there was less lipid available than the amount required for complete bilayer coverage of the SiO(2), resulted in precipitation of the nanosystem by a process of nanoparticle lipid bridging. For this case, we postulate a process in which lipid bilayer patches on one nanoparticle collide with bare silica patches on another SiO(2) nanoparticle, forming a single bilayer bridge between them. TEM data confirmed these findings, thus indicating that lipid bridges are composed of half bilayers on adjoining SiO(2) nanoparticles. PMID:21500811

  13. An emerging role of mTOR in lipid biosynthesis

    E-print Network

    Laplante, Mathieu

    Lipid biosynthesis is essential for the maintenance of cellular homeostasis. The lipids produced by cells (glycerolipids, fatty acids, phospholipids, cholesterol, and sphingolipids) are used as an energy source/reserve, ...

  14. Short communication Fabrication of solid lipid microcapsules containing ascorbic acid

    E-print Network

    Short communication Fabrication of solid lipid microcapsules containing ascorbic acid using Encapsulation efficiency Lipid shell a b s t r a c t The importance of ascorbic acid (AA) in the human diet has

  15. Hydrogen isotope fractionation during lipid biosynthesis by Haloarcula marismortui

    E-print Network

    Hydrogen isotope fractionation during lipid biosynthesis by Haloarcula marismortui Sitindra S studied the controls on the fractionation of hydrogen isotopes during lipid biosynthesis by Haloarcula marismortui, a halophilic archaea, in pure culture experiments by varying organic substrate, the hydrogen

  16. Lipid Raft: A Floating Island Of Death or Survival

    PubMed Central

    George, Kimberly S.; Wu, Shiyong

    2012-01-01

    Lipid rafts are microdomains of the plasma membrane enriched in cholesterol and sphingolipids, and play an important role in the initiation of many pharmacological agent-induced signaling pathways and toxicological effects. The structure of lipid rafts is dynamic, resulting in an ever-changing content of both lipids and proteins. Cholesterol, as a major component of lipid rafts, is critical for the formation and configuration of lipid rafts microdomains, which provide signaling platforms capable of activating both pro-apoptotic and anti-apoptotic signaling pathways. A change of cholesterol level can result in lipid rafts disruption and activate or deactivate raft-associated proteins, such as death receptor proteins, protein kinases, and calcium channels. Several anti-cancer drugs are able to suppress growth and induce apoptosis of tumor cells through alteration of lipid raft contents via disrupting lipid raft integrity. PMID:22289360

  17. LipidII: Just Another Brick in the Wall?

    PubMed Central

    Scheffers, Dirk-Jan; Tol, Menno B.

    2015-01-01

    Nearly all bacteria contain a peptidoglycan cell wall. The peptidoglycan precursor molecule is LipidII, containing the basic peptidoglycan building block attached to a lipid. Although the suitability of LipidII as an antibacterial target has long been recognized, progress on elucidating the role(s) of LipidII in bacterial cell biology has been slow. The focus of this review is on exciting new developments, both with respect to antibacterials targeting LipidII as well as the emerging role of LipidII in organizing the membrane and cell wall synthesis. It appears that on both sides of the membrane, LipidII plays crucial roles in organizing cytoskeletal proteins and peptidoglycan synthesis machineries. Finally, the recent discovery of no less than three different categories of LipidII flippases will be discussed. PMID:26679002

  18. Importance of the hexagonal lipid phase in biological membrane organization

    PubMed Central

    Jouhet, Juliette

    2013-01-01

    Domains are present in every natural membrane. They are characterized by a distinctive protein and/or lipid composition. Their size is highly variable from the nano- to the micrometer scale. The domains confer specific properties to the membrane leading to original structure and function. The determinants leading to domain organization are therefore important but remain obscure. This review presents how the ability of lipids to organize into hexagonal II or lamellar phases can promote particular local structures within membranes. Since biological membranes are composed of a mixture of lipids, each with distinctive biophysical properties, lateral and transversal sorting of lipids can promote creation of domains inside the membrane through local modulation of the lipid phase. Lipid biophysical properties have been characterized for long based on in vitro analyses using non-natural lipid molecules; their re-examinations using natural lipids might open interesting perspectives on membrane architecture occurring in vivo in various cellular and physiological contexts. PMID:24348497

  19. Importance of the hexagonal lipid phase in biological membrane organization.

    PubMed

    Jouhet, Juliette

    2013-01-01

    Domains are present in every natural membrane. They are characterized by a distinctive protein and/or lipid composition. Their size is highly variable from the nano- to the micrometer scale. The domains confer specific properties to the membrane leading to original structure and function. The determinants leading to domain organization are therefore important but remain obscure. This review presents how the ability of lipids to organize into hexagonal II or lamellar phases can promote particular local structures within membranes. Since biological membranes are composed of a mixture of lipids, each with distinctive biophysical properties, lateral and transversal sorting of lipids can promote creation of domains inside the membrane through local modulation of the lipid phase. Lipid biophysical properties have been characterized for long based on in vitro analyses using non-natural lipid molecules; their re-examinations using natural lipids might open interesting perspectives on membrane architecture occurring in vivo in various cellular and physiological contexts. PMID:24348497

  20. New paper chromatographic procedures for fractionating the lipides 

    E-print Network

    Dieckert, Julius Walter

    1955-01-01

    -4 Therefore, studying ligand-receptor interactions at appropriate model membrane is of importance for both proper understanding of biological functions and applications to biosensors and bioseparations. Supported lipid bilayers are composed of the same lipid...

  1. 21 CFR 862.1470 - Lipid (total) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...in serum and plasma. Lipid (total) measurements are used in the diagnosis and treatment of various diseases involving lipid metabolism and atherosclerosis. (b) Classification. Class I (general controls). The device is exempt from the premarket...

  2. 21 CFR 862.1470 - Lipid (total) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Lipid (total) measurements are used in the diagnosis and treatment of various diseases involving lipid metabolism and atherosclerosis. (b) Classification. Class I (general controls). The device is exempt from the premarket...

  3. 21 CFR 862.1470 - Lipid (total) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Lipid (total) measurements are used in the diagnosis and treatment of various diseases involving lipid metabolism and atherosclerosis. (b) Classification. Class I (general controls). The device is exempt from the premarket...

  4. 21 CFR 862.1470 - Lipid (total) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...Lipid (total) measurements are used in the diagnosis and treatment of various diseases involving lipid metabolism and atherosclerosis. (b) Classification. Class I (general controls). The device is exempt from the premarket...

  5. Near infrared Raman spectra of human brain lipids

    NASA Astrophysics Data System (ADS)

    Krafft, Christoph; Neudert, Lars; Simat, Thomas; Salzer, Reiner

    2005-05-01

    Human brain tissue, in particular white matter, contains high lipid content. These brain lipids can be divided into three principal classes: neutral lipids including the steroid cholesterol, phospholipids and sphingolipids. Major lipids in normal human brain tissue are phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, phosphatidic acid, sphingomyelin, galactocerebrosides, gangliosides, sulfatides and cholesterol. Minor lipids are cholesterolester and triacylglycerides. During transformation from normal brain tissue to tumors, composition and concentration of lipids change in a specific way. Therefore, analysis of lipids might be used as a diagnostic parameter to distinguish normal tissue from tumors and to determine the tumor type and tumor grade. Raman spectroscopy has been suggested as an analytical tool to detect these changes even under intra-operative conditions. We recorded Raman spectra of the 12 major and minor brain lipids with 785 nm excitation in order to identify their spectral fingerprints for qualitative and quantitative analyses.

  6. Hydrothermal processing of high-lipid biomass to fuels

    E-print Network

    Johnson, Michael C., Ph. D. Massachusetts Institute of Technology

    2012-01-01

    High-lipid algae are potential sources of biofuels. Lipids in this biomass provide a straightforward chemical route to hydrocarbon-based high energy-density fuels needed for diesel and jet engines. However, current schemes ...

  7. An Introduction to Lipid Analysis in the Cell Biology Laboratory.

    ERIC Educational Resources Information Center

    Schuh, Timothy J.

    2002-01-01

    Explains a thin-layer chromatography (TLC) experiment that allows students to study complex mixtures of lipids using small volumes. Uses a water-soluble dye to stain lipids that is fast and safe. (YDS)

  8. Irregular bilayer structure in vesicles prepared from Halobacterium cutirubrum lipids

    NASA Technical Reports Server (NTRS)

    Lanyi, J. K.

    1974-01-01

    Fluorescent probes were used to study the structure of the cell envelope of Halobacterium cutirubrum, and, in particular, to explore the effect of the heterogeneity of the lipids in this organism on the structure of the bilayers. The fluorescence polarization of perylene was followed in vesicles of unfractionated lipids and polar lipids as a function of temperature in 3.4 M solutions of NaCl, NaNO3, and KSCN, and it was found that vesicles of unfractionated lipids were more perturbed by chaotropic agents than polar lipids. The dependence of the relaxation times of perylene on temperature was studied in cell envelopes and in vesicles prepared from polar lipids, unfractionated lipids, and mixtures of polar and neutral lipids.

  9. Assay of Flippase Activity in Proteoliposomes Using Fluorescent Lipid Derivatives.

    PubMed

    Marek, Magdalena; Günther-Pomorski, Thomas

    2016-01-01

    Specific membrane proteins, termed lipid flippases, play a central role in facilitating the movement of lipids across cellular membranes. In this protocol, we describe the reconstitution of ATP-driven lipid flippases in liposomes and the analysis of their in vitro flippase activity based on the use of fluorescent lipid derivatives. Working with purified and reconstituted systems provides a well-defined experimental setup and allows to directly characterize these membrane proteins at the molecular level. PMID:26695033

  10. Density and viscosity of lipids under pressure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is a lack of data for the viscosity of lipids under pressure. The current report is a part of the effort to fill this gap. The viscosity, density, and elastohydrodynamic film thicknesses of vegetable oil (HOSuO) were investigated. Pressure–viscosity coefficients (PVC) of HOSuO at different tem...

  11. Starch-lipid composites containing cimmamaldehyde

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The formulation of a starch-lipid composite containing cinnamaldehyde as antimicrobial agent has been studied. Cinnamaldehyde was incorporated as an emulsion using Acetem 90-50K as a carrier and Tween 60 as the emulsifier. Oil in water emulsions were prepared by direct emulsification using a high sh...

  12. The lipid biosynthesis hole in the rickettsiales

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a complementation assay in E. coli, we have shown that the propionyl-CoA carboxylase complex (PCC) from Wolbachia pipientis wMel, order Rickettsiales, provides for lipid biosynthesis through malonyl-CoA production. Normally, the prototypical prokaryote fatty acid synthesis (FASII) initiation ...

  13. Micropattern Formation in Supported Lipid Membranes

    E-print Network

    Boxer, Steven G.

    experimental platform for the study and utilization of lipid membranes. Introduction The phospholipid bilayer. A supported membrane is generally defined as a single, continuous phospholipid bilayer on a solid or polymeric, California 94720 Received July 17, 2001 ABSTRACT Phospholipid vesicles exhibit a natural tendency to fuse

  14. Engineering Lipid Bilayer Membranes for Protein Studies

    PubMed Central

    Khan, Muhammad Shuja; Dosoky, Noura Sayed; Williams, John Dalton

    2013-01-01

    Lipid membranes regulate the flow of nutrients and communication signaling between cells and protect the sub-cellular structures. Recent attempts to fabricate artificial systems using nanostructures that mimic the physiological properties of natural lipid bilayer membranes (LBM) fused with transmembrane proteins have helped demonstrate the importance of temperature, pH, ionic strength, adsorption behavior, conformational reorientation and surface density in cellular membranes which all affect the incorporation of proteins on solid surfaces. Much of this work is performed on artificial templates made of polymer sponges or porous materials based on alumina, mica, and porous silicon (PSi) surfaces. For example, porous silicon materials have high biocompatibility, biodegradability, and photoluminescence, which allow them to be used both as a support structure for lipid bilayers or a template to measure the electrochemical functionality of living cells grown over the surface as in vivo. The variety of these media, coupled with the complex physiological conditions present in living systems, warrant a summary and prospectus detailing which artificial systems provide the most promise for different biological conditions. This study summarizes the use of electrochemical impedance spectroscopy (EIS) data on artificial biological membranes that are closely matched with previously published biological systems using both black lipid membrane and patch clamp techniques. PMID:24185908

  15. Variation in seed lipids in Calendula germplasm

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calendula officinalis (pot marigold) has considerable promise as an industrial crop, with a long history as an ornamental and medicinal plant. It is also marketed as an ingredient in cosmetics and a colorant. It produces unusual seed lipids, which can provide an additional market for commercial Ca...

  16. Many Roads Lead to the Lipid Droplet

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this journal article, we review the recent work by Farese and colleagues (Functional genomic screen reveals genes involved in lipid-droplet formation and utilization. Guo Y, Walther TC, Rao M, Stuurman N, Goshima G, Terayama K, Wong JS, Vale RD, Walter P, Farese RV. Nature. 2008 May 29;453(7195):...

  17. Anaphylaxis caused by tomato lipid transfer protein.

    PubMed

    Asero, R; Mistrello, G; Amato, S

    2011-08-01

    This study reports an unusual case of anaphylaxis induced by tomato. Inhibition studies carried out in-vitro showed the complete cross-reactivity between the relevant tomato allergen and purified peach lipid transferprotein (LTP). Tomato LTP may sometimes cause severe allergic reactions. PMID:21980801

  18. Molecular Transport Studies Through Unsupported Lipid Membranes

    NASA Astrophysics Data System (ADS)

    Rock, William; Parekh, Sapun; Bonn, Mischa

    2014-03-01

    Dendrimers, spherical polymeric nanoparticles made from branched monomers around a central core, show great promise as drug delivery vehicles. Dendrimer size, core contents, and surface functionality can be synthetically tuned, providing unprecedented versatility. Polyamidoamine (PAMAM) dendrimers have been shown to enter cells; however, questions remain about their biophysical interactions with the cell membrane, specifically about the presence and size of transient pores. We monitor dendrimer-lipid bilayer interactions using unsupported black lipid membranes (BLMs) as model cell membranes. Custom bilayer slides contain two vertically stacked aqueous chambers separated by a 25 ?m Teflon sheet with a 120 ?m aperture where the bilayer is formed. We vary the composition of model membranes (cholesterol content and lipid phase) to create biomimetic systems and study the interaction of PAMAM G6 and G3 dendrimers with these bilayers. Dendrimers, dextran cargo, and bilayers are monitored and quantified using time-lapse fluorescence imaging. Electrical capacitance measurements are simultaneously recorded to determine if the membrane is porous, and the pore size is deduced by monitoring transport of fluorescent dextrans of increasing molecular weight. These experiments shed light on the importance of cholesterol content and lipid phase on the interaction of dendrimer nanoparticles with membranes.

  19. Pyrolysis of lipids using various catalysts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A specific pursuit of the thermochemical (combustion, gasification, pyrolysis, and liquefaction) conversion of biomass to energy research effort is the potential of converting lipids to alkanes, petroleum-like fuels and chemicals. Arguments can be made for, and against, the use of agricultural lipi...

  20. The organization of melatonin in lipid membranes.

    PubMed

    Dies, Hannah; Cheung, Bonnie; Tang, Jennifer; Rheinstädter, Maikel C

    2015-04-01

    Melatonin is a hormone that has been shown to have protective effects in several diseases that are associated with cholesterol dysregulation, including cardiovascular disease, Alzheimer's disease, and certain types of cancers. We studied the interaction of melatonin with model membranes made of dimyristoylphosphatidylcholine (DMPC) at melatonin concentrations ranging from 0.5mol% to 30mol%. From 2-dimensional X-ray diffraction measurements, we find that melatonin induces a re-ordering of the lipid membrane that is strongly dependent on the melatonin concentration. At low melatonin concentrations, we observe the presence of melatonin-enriched patches in the membrane, which are significantly thinner than the lipid bilayer. The melatonin molecules were found to align parallel to the lipid tails in these patches. At high melatonin concentrations of 30mol%, we observe a highly ordered melatonin structure that is uniform throughout the membrane, where the melatonin molecules align parallel to the bilayers and one melatonin molecule associates with 2 lipid molecules. Understanding the organization and interactions of melatonin in membranes, and how these are dependent on the concentration, may shed light into its anti-amyloidogenic, antioxidative and photoprotective properties and help develop a structural basis for these properties. PMID:25602914

  1. Lipid and Fatty Acid Requirements of Tilapia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dietary lipids are an important source of highly digestible energy and are the only source of essential fatty acids required for normal growth and development. They are also carriers and assist in the absorption of fat-soluble nutrients, such as sterols and fat-soluble vitamins, serve as a source of...

  2. Waxes: A Forgotten Topic in Lipid Teaching.

    ERIC Educational Resources Information Center

    Dominguez, Eva; Heredia, Antonio

    1998-01-01

    Reviews the biological importance of the lipids categorized as waxes and describes some of the organic chemistry of these compounds. Presents a short laboratory exercise on the extraction of plant waxes and their analysis by thin layer chromatography. (Author/CCM)

  3. Lipid-based colloidal carriers for peptide and protein delivery – liposomes versus lipid nanoparticles

    PubMed Central

    Martins, Susana; Sarmento, Bruno; Ferreira, Domingos C; Souto, Eliana B

    2007-01-01

    This paper highlights the importance of lipid-based colloidal carriers and their pharmaceutical implications in the delivery of peptides and proteins for oral and parenteral administration. There are several examples of biomacromolecules used nowadays in the therapeutics, which are promising candidates to be delivered by means of liposomes and lipid nanoparticles, such as solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC). Several production procedures can be applied to achieve a high association efficiency between the bioactives and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. Generally, this can lead to improved bioavailability, or in case of oral administration a more consistent temporal profile of absorption from the gastrointestinal tract. Advantages and drawbacks of such colloidal carriers are also pointed out. This article describes strategies used for formulation of peptides and proteins, methods used for assessment of association efficiency and practical considerations regarding the toxicological concerns. PMID:18203427

  4. Dietary lipid source and vitamin e influence on chicken meat quality and lipid oxidation stability 

    E-print Network

    Narciso-Gaytan, Carlos

    2009-05-15

    lipid oxidation development and quality characteristics of chicken meat as affected by dietary fat and vitamin E levels. Broilers were fed during six weeks with diets containing animal/vegetable, lard, palm kernel, soybean, conjugated linoleic acid...

  5. Deciphering tissue-induced Klebsiella pneumoniae lipid A structure.

    PubMed

    Llobet, Enrique; Martínez-Moliner, Verónica; Moranta, David; Dahlström, Käthe M; Regueiro, Verónica; Tomás, Anna; Cano, Victoria; Pérez-Gutiérrez, Camino; Frank, Christian G; Fernández-Carrasco, Helena; Insua, José Luis; Salminen, Tiina A; Garmendia, Junkal; Bengoechea, José A

    2015-11-17

    The outcome of an infection depends on host recognition of the pathogen, hence leading to the activation of signaling pathways controlling defense responses. A long-held belief is that the modification of the lipid A moiety of the lipopolysaccharide could help Gram-negative pathogens to evade innate immunity. However, direct evidence that this happens in vivo is lacking. Here we report the lipid A expressed in the tissues of infected mice by the human pathogen Klebsiella pneumoniae. Our findings demonstrate that Klebsiella remodels its lipid A in a tissue-dependent manner. Lipid A species found in the lungs are consistent with a 2-hydroxyacyl-modified lipid A dependent on the PhoPQ-regulated oxygenase LpxO. The in vivo lipid A pattern is lost in minimally passaged bacteria isolated from the tissues. LpxO-dependent modification reduces the activation of inflammatory responses and mediates resistance to antimicrobial peptides. An lpxO mutant is attenuated in vivo thereby highlighting the importance of this lipid A modification in Klebsiella infection biology. Colistin, one of the last options to treat multidrug-resistant Klebsiella infections, triggers the in vivo lipid A pattern. Moreover, colistin-resistant isolates already express the in vivo lipid A pattern. In these isolates, LpxO-dependent lipid A modification mediates resistance to colistin. Deciphering the lipid A expressed in vivo opens the possibility of designing novel therapeutics targeting the enzymes responsible for the in vivo lipid A pattern. PMID:26578797

  6. Molecular driving forces defining lipid positions around aquaporin-0

    E-print Network

    de Groot, Bert

    these phospholipids to- wards AQP0. Instead, the mobility of the protein crucially modu- lates the lipid localization crystallography lipd bilayer atomistic simulations Lipids and membrane proteins form biological membranes that constitute the boundary of cells and their intracellular com- partments. Lipids arrange in a bilayer

  7. Lipid Catabolism of Invertebrate Predator Indicates Widespread Wetland Ecosystem Degradation

    E-print Network

    Afton, Alan D.

    Lipid Catabolism of Invertebrate Predator Indicates Widespread Wetland Ecosystem Degradation and was markedly greater than in any region of the upper Midwest. Our results indicate that females catabolized rather than stored lipid reserves throughout the upper Midwest. Moreover, levels of lipid catabolism

  8. Lipid composition of tissue and plasma in two mediterranean fishes,

    E-print Network

    McClelland, Grant B.

    in water salinity andlor temperature ponent of cellular membranes. They are stored primarily (Bell et al that of the diet and different in the two species. Contribution to tissue wet weight of the different lipid in adipose tissue (about 80% lipid-wet weight-'). Seabass store 33% wet weight of lipid in liver, while sea

  9. Distension-induced gradient capillarity in lipid membranes

    NASA Astrophysics Data System (ADS)

    Kim, Chun-Il; Steigmann, David J.

    2015-09-01

    A model for lipid membranes with lipid distension is presented. This incorporates the conventional Helfrich-type formulation as a special case. The effects of lipid distension on the shape equation, and the required adjustments to operative edge conditions, are discussed in detail. The model is illustrated through numerical simulations.

  10. Ordered Nanoclusters in Lipid-Cholesterol Membranes Maria K. Ratajczak

    E-print Network

    Lee, Ka Yee C.

    Ordered Nanoclusters in Lipid-Cholesterol Membranes Maria K. Ratajczak Department of Physics comprising the plasma membrane are inhomogeneously distributed, form- ing liquid domains rich in cholesterol and the role cholesterol plays on mem- brane lipid organization remain unresolved. Characteriza- tion of lipid

  11. Final Report: 17th international Symposium on Plant Lipids

    SciTech Connect

    Christoph Benning

    2007-03-07

    This meeting covered several emerging areas in the plant lipid field such as the biosynthesis of cuticle components, interorganelle lipid trafficking, the regulation of lipid homeostasis, and the utilization of algal models. Stimulating new insights were provided not only based on research reports based on plant models, but also due to several excellent talks by experts from the yeast field.

  12. Chemical Changes in Lipids Produced by Thermal Processing.

    ERIC Educational Resources Information Center

    Nawar, Wassef W.

    1984-01-01

    Describes heat effects on lipids, indicating that the chemical and physical changes that occur depend on the lipid's composition and conditions of treatment. Thermolytic and oxidation reactions, thermal/oxidative interaction of lipids with other food components and the chemistry of frying are considered. (JN)

  13. A Teaching Laboratory for Comprehensive Lipid Characterization from Food Samples

    ERIC Educational Resources Information Center

    Bendinskas, Kestutis; Weber, Benjamin; Nsouli, Tamara; Nguyen, Hoangvy V.; Joyce, Carolyn; Niri, Vadoud; Jaskolla, Thorsten W.

    2014-01-01

    Traditional and state-of-the-art techniques were combined to probe for various lipid classes from egg yolk and avocado qualitatively and quantitatively. A total lipid extract was isolated using liquid-liquid extraction. An aliquot of the total lipid extract was subjected to transesterification to form volatile fatty acid methyl esters suitable for…

  14. Structure of a lipid-bound extended synaptotagmin indicates a role in lipid transfer.

    PubMed

    Schauder, Curtis M; Wu, Xudong; Saheki, Yasunori; Narayanaswamy, Pradeep; Torta, Federico; Wenk, Markus R; De Camilli, Pietro; Reinisch, Karin M

    2014-06-26

    Growing evidence suggests that close appositions between the endoplasmic reticulum (ER) and other membranes, including appositions with the plasma membrane (PM), mediate exchange of lipids between these bilayers. The mechanisms of such exchange, which allows lipid transfer independently of vesicular transport, remain poorly understood. The presence of a synaptotagmin-like mitochondrial-lipid-binding protein (SMP) domain, a proposed lipid-binding module, in several proteins localized at membrane contact sites has raised the possibility that such domains may be implicated in lipid transport. SMP-containing proteins include components of the ERMES complex, an ER–mitochondrial tether, and the extended synaptotagmins (known as tricalbins in yeast), which are ER–PM tethers. Here we present at 2.44 Å resolution the crystal structure of a fragment of human extended synaptotagmin 2 (E-SYT2), including an SMP domain and two adjacent C2 domains. The SMP domain has a ?-barrel structure like protein modules in the tubular-lipid-binding (TULIP) superfamily. It dimerizes to form an approximately 90-Å-long cylinder traversed by a channel lined entirely with hydrophobic residues, with the two C2A–C2B fragments forming arched structures flexibly linked to the SMP domain. Importantly, structural analysis complemented by mass spectrometry revealed the presence of glycerophospholipids in the E-SYT2 SMP channel, indicating a direct role for E-SYTs in lipid transport. These findings provide strong evidence for a role of SMP-domain-containing proteins in the control of lipid transfer at membrane contact sites and have broad implications beyond the field of ER-to-PM appositions. PMID:24847877

  15. JAZF1 can regulate the expression of lipid metabolic genes and inhibit lipid accumulation in adipocytes

    SciTech Connect

    Ming, Guang-feng; Xiao, Di; Gong, Wei-jing; Liu, Hui-xia; Liu, Jun; Zhou, Hong-hao; Liu, Zhao-qian

    2014-03-14

    Highlights: • JAZF1 was significantly upregulated during the differentiation of 3T3-L1 preadipocytes. • JAZF1 overexpression inhibited lipid accumulation in differentiated mature 3T3-L1 adipocytes. • JAZF1 overexpression inhibited the expression of SREBP1, ACC, and FAS. • JAZF1 overexpression upregulated the expression of HSL and ATGL. • SREBP1 and JAZF1 could regulate each other in adipocytes. - Abstract: JAZF1 is a newly identified gene with unknown functions. A recent genome-wide association study showed that JAZF1 is associated with type 2 diabetes and is highly expressed in liver and adipose tissue. Studies have demonstrated that JAZF1 is the co-repressor for nuclear orphan receptor TAK1, whereas most nuclear orphan receptor family members are involved in the regulation of lipid metabolism. Therefore, JAZF1 could be closely related to glycolipid metabolism. In this study, JAZF1 was significantly upregulated during the induced differentiation process of 3T3-L1 preadipocytes. The overexpression of JAZF1 inhibited lipid accumulation in differentiated mature 3T3-L1 adipocytes and significantly inhibited the expression of SREBPl, ACC, and FAS, which were important in lipid synthesis, while upregulating the expression of key enzyme hormone-sensitive lipase in lipoclasis. Moreover, SREBPl exhibited an inhibitory function on the expression of JAZF1. SREBP1 reversed the inhibitory action on lipid accumulation of JAZF1. SREBP1 and JAZF1 were observed to regulate each other in adipocytes. Therefore, JAZF1 could regulate the expression of particular genes related to lipid metabolism and inhibit lipid accumulation in adipocytes. This result suggests that JAZF1 may be a potential target for the treatment of diseases, such as obesity and lipid metabolism disorders.

  16. Immune modulation by parenteral lipid emulsions.

    PubMed

    Wanten, Geert J A; Calder, Philip C

    2007-05-01

    Total parenteral nutrition is the final option for nutritional support of patients with severe intestinal failure. Lipid emulsions constitute the main source of fuel calories and fatty acids (FAs) in parenteral nutrition formulations. However, adverse effects on patient outcomes have been attributed to the use of lipids, mostly in relation to impaired immune defenses and altered inflammatory responses. Over the years, this issue has remained in the limelight, also because technical advances have provided no safeguard against the most daunting problems, ie, infectious complications. Nevertheless, numerous investigations have failed to produce a clear picture of the immunologic characteristics of the most commonly used soybean oil-derived lipid emulsions, although their high content of n-6 polyunsaturated FAs (PUFAs) has been considered a drawback because of their proinflammatory potential. This concern initiated the development of emulsions in which part of the n-6 FA component is replaced by less bioactive FAs, such as coconut oil (rich in medium-chain saturated FAs) or olive oil (rich in the n-9 monounsaturated FA oleic acid). Another approach has been to use fish oil (rich in n-3 PUFA), the FAs of which have biological activities different from those of n-6 PUFAs. Recent studies on the modulation of host defenses and inflammation by fish-oil emulsions have yielded consistent data, which indicate that these emulsions may provide a tool to beneficially alter the course of immune-mediated conditions. Although most of these lipids have not yet become available on the US market, this review synthesizes available information on immunologic characteristics of the different lipids that currently can be applied via parenteral nutrition support. PMID:17490951

  17. Binding Orientations and Lipid Interactions of Human Amylin at Zwitterionic and Anionic Lipid Bilayers

    PubMed Central

    Qian, Zhenyu; Jia, Yan; Wei, Guanghong

    2016-01-01

    Increasing evidence suggests that the interaction of human islet amyloid polypeptide (hIAPP) with lipids may facilitate hIAPP aggregation and cause the death of pancreatic islet ?-cells. However, the detailed hIAPP-membrane interactions and the influences of lipid compositions are unclear. In this study, as a first step to understand the mechanism of membrane-mediated hIAPP aggregation, we investigate the binding behaviors of hIAPP monomer at zwitterionic palmitoyloleoyl-phosphatidylcholine (POPC) bilayer by performing atomistic molecular dynamics simulations. The results are compared with those of hIAPP at anionic palmitoyloleoyl-phosphatidylglycerol (POPG) bilayers. We find that the adsorption of hIAPP to POPC bilayer is mainly initiated from the C-terminal region and the peptide adopts a helical structure with multiple binding orientations, while the adsorption to POPG bilayer is mostly initiated from the N-terminal region and hIAPP displays one preferential binding orientation, with its hydrophobic residues exposed to water. hIAPP monomer inserts into POPC lipid bilayers more readily than into POPG bilayers. Peptide-lipid interaction analyses show that the different binding features of hIAPP at POPC and POPG bilayers are attributed to different magnitudes of electrostatic and hydrogen-bonding interactions with lipids. This study provides mechanistic insights into the different interaction behaviors of hIAPP with zwitterionic and anionic lipid bilayers. PMID:26649316

  18. Enhanced bioavailability of tripterine through lipid nanoparticles using broccoli-derived lipids as a carrier material.

    PubMed

    Li, Wan; Zhang, Tianpeng; Ye, Yanghuan; Zhang, Xingwang; Wu, Baojian

    2015-11-30

    Chemotherapy via the oral route remains a considerable challenge due to poor water-solubility and permeability of anticancer agents. This study aimed to construct lipid nanoparticles using broccoli-derived lipids for oral delivery of tripterine (Tri), a natural anticancer candidate, and to enhance its oral bioavailability. Tri-loaded broccoli lipid nanoparticles (Tri-BLNs) were prepared by a solvent-diffusion method. The resulting Tri-BLNs were 75±10nm in particle size with entrapment efficiency over 98%. In vitro release study indicated that Tri was almost not released from Tri-BLNs (<2%), whereas the lipolytic experiment showed that Tri-BLNs possessed a relatively strong anti-enzymatic degradation ability to Tri-CLNs (Tri-loaded common lipid nanoparticles). In situ single-pass intestinal perfusion manifested that the effective permeability of Tri-BLNs were significantly higher than that of Tri-CLNs. Further, Tri-BLNs exhibited more efficient cellular uptake in MDCK-II cells as evidenced by flow cytometry and confocal microscopy. The relative bioavailability of Tri-BLNs and Tri-CLNs was 494.13% and 281.95% compared with Tri suspensions, respectively. Depending on the ability in enhancement of biomembrane permeability, broccoli-derived lipids as an alternative source should be useful to construct lipid nanoparticles for bettering oral delivery of drugs with low bioavailability. PMID:26453780

  19. Lipid Vesicles for the Skin Delivery of Diclofenac: Cerosomes vs. Other Lipid Suspensions

    PubMed Central

    Fathi-Azarbayjani, Anahita; Ng, Kai Xin; Chan, Yew Weng; Chan, Sui Yung

    2015-01-01

    Purpose: Lipid suspensions as drug carriers, including conventional liposomes, ethosomes, transferosomes, proniosomes, niosomes, PEG-PPG-PEG niosomes and stratum corneum liposomes (cerosomes), were formulated and compared. Methods: Lipid vesicles were formulated and assessed with regards to enhancement of skin permeation of diclofenac and stability profiles of the formulations. Formulation-induced changes of the biophysical structure of excised human skin were monitored using the Fourier transform infrared spectroscopy. Results: The stability profiles of these suspensions over 12 weeks did not show any significant drug leakage from the vesicles of interest (p > 0.05). FTIR observations indicated that the vesicles increased stratum corneum (SC) lipid fluidization and altered protein conformation. Skin permeability experiments showed that the free unencapsulated drug in the cerosomal formulations caused significant increase in drug permeation across the skin (p < 0.01). Low skin permeability of drug from the other lipid suspensions could be due to the entrapment of diclofenac within these vesicles which decreased the solubility of the hydrophilic drug in the skin lipids and the partition coefficient of the drug from these vesicles into the SC. Conclusion: Optimal drug entrapment in vesicles or alteration of the skin structure may not necessarily enhance the permeation of hydrophilic drugs across the human skin. These lipid vesicles may be further developed into carriers of both hydrophilic and hydrophobic drugs for topical and transdermal delivery, respectively. PMID:25789216

  20. Binding Orientations and Lipid Interactions of Human Amylin at Zwitterionic and Anionic Lipid Bilayers.

    PubMed

    Qian, Zhenyu; Jia, Yan; Wei, Guanghong

    2016-01-01

    Increasing evidence suggests that the interaction of human islet amyloid polypeptide (hIAPP) with lipids may facilitate hIAPP aggregation and cause the death of pancreatic islet ?-cells. However, the detailed hIAPP-membrane interactions and the influences of lipid compositions are unclear. In this study, as a first step to understand the mechanism of membrane-mediated hIAPP aggregation, we investigate the binding behaviors of hIAPP monomer at zwitterionic palmitoyloleoyl-phosphatidylcholine (POPC) bilayer by performing atomistic molecular dynamics simulations. The results are compared with those of hIAPP at anionic palmitoyloleoyl-phosphatidylglycerol (POPG) bilayers. We find that the adsorption of hIAPP to POPC bilayer is mainly initiated from the C-terminal region and the peptide adopts a helical structure with multiple binding orientations, while the adsorption to POPG bilayer is mostly initiated from the N-terminal region and hIAPP displays one preferential binding orientation, with its hydrophobic residues exposed to water. hIAPP monomer inserts into POPC lipid bilayers more readily than into POPG bilayers. Peptide-lipid interaction analyses show that the different binding features of hIAPP at POPC and POPG bilayers are attributed to different magnitudes of electrostatic and hydrogen-bonding interactions with lipids. This study provides mechanistic insights into the different interaction behaviors of hIAPP with zwitterionic and anionic lipid bilayers. PMID:26649316

  1. Triton WR-1339-induced changes in serum lipids and biliary lipid secretion.

    PubMed

    Zeniya, M; Reuben, A

    1988-03-01

    Biliary lipid secretion rates were measured in fed rats after an intravenous injection of Triton WR-1339 (TWR, 60 mg/100 g body wt), an agent that inhibits lipoprotein removal from the circulation. Serum triglyceride, phospholipid (PL), and cholesterol (CH) concentrations rose within 3 h of TWR to 45, 6.6, and 10 times control values, respectively, at 24-36 h. Serum lipids fell rapidly at 48 h and were normal by 72-96 h after TWR. TWR did not alter bile flow, hepatic bile acid transport, or biliary bile acid output. Within 0.5 h of TWR, biliary PL and CH outputs fell greater than 70%, and taurocholate-stimulated biliary PL secretion was markedly reduced. Biliary PL and CH secretion rates were approximately 30 and approximately 40% suppressed, respectively, 24 h after TWR, 160 and 330% elevated, respectively, at 48 h, and normally by 72 h, despite normal taurocholate-stimulated biliary PL secretion. Biliary beta-glucuronidase secretion (a lysosomal enzyme) was unchanged for 3 h after TWR but was increased at 24, 48, and 72 h, independent of biliary lipid secretion. Thus TWR acutely dissociates bile acid from lipid secretion without impairing bile acid transport or biliary lysosomal discharge. Late changes in biliary lipid secretion relate closely to TWR-induced change in serum lipid metabolism but not to stimulation of biliary lysosomal discharge. PMID:3348401

  2. Lipid tail protrusions initiate spontaneous insertion of charged, amphiphilic nanoparticles into lipid bilayers

    NASA Astrophysics Data System (ADS)

    van Lehn, Reid; Ricci, Maria; Carney, Randy; Voitchovsky, Kislon; Stellacci, Francesco; Alexander-Katz, Alfredo

    2014-03-01

    Vesicle fusion is a primary mechanism used to mediate the uptake and trafficking of materials both into and between cells. The pathway of vesicle fusion involves the formation of a lipid stalk in which the hydrophobic core regions of two closely associated bilayers merge. The transition state for stalk formation requires the transient protrusion of hydrophobic lipid tails into solvent; favorable contact between these hydrophobic tails then drives stalk creation. In this work, we use unbiased atomistic molecular dynamics simulations to show that lipid tail protrusions can also induce the insertion of charged, amphiphilic nanoparticles (NPs) into lipid bilayers. As in the case of vesicle fusion, the rate-limiting step for NP-bilayer fusion is the stochastic protrusion of aliphatic lipid tails into solvent and into contact with hydrophobic material in the amphiphilic NP monolayer. We confirm our predictions with experiments on supported lipid bilayers. The strong agreement between simulation and experiments indicates that the pre-stalk transition associated with vesicle fusion may be a general mechanism for the insertion of amphiphilic nano-objects that could be prominent in biological systems given the widespread use of NPs in applications ranging from drug delivery to biosensing.

  3. Solid lipid nanoparticles of guggul lipid as drug carrier for transdermal drug delivery.

    PubMed

    Gaur, Praveen Kumar; Mishra, Shikha; Purohit, Suresh

    2013-01-01

    Diclofenac sodium loaded solid lipid nanoparticles (SLNs) were formulated using guggul lipid as major lipid component and analyzed for physical parameters, permeation profile, and anti-inflammatory activity. The SLNs were prepared using melt-emulsion sonication/low temperature-solidification method and characterized for physical parameters, in vitro drug release, and accelerated stability studies, and formulated into gel. Respective gels were compared with a commercial emulgel (CEG) and plain carbopol gel containing drug (CG) for ex vivo and in vivo drug permeation and anti-inflammatory activity. The SLNs were stable with optimum physical parameters. GMS nanoparticle 1 (GMN-1) and stearic acid nanoparticle 1 (SAN-1) gave the highest in vitro drug release. Guggul lipid nanoparticle gel 3 (GLNG-3) showed 104.68 times higher drug content than CEG in receptor fluid. The enhancement ratio of GLNG-3 was 39.43 with respect to CG. GLNG-3 showed almost 8.12 times higher C(max) than CEG at 4 hours. The AUC value of GLNG-3 was 15.28 times higher than the AUC of CEG. GLNG-3 showed edema inhibition up to 69.47% in the first hour. Physicochemical properties of major lipid component govern the properties of SLN. SLN made up of guggul lipid showed good physical properties with acceptable stability. Furthermore, it showed a controlled drug release profile along with a promising permeation profile. PMID:24058913

  4. Solid Lipid Nanoparticles of Guggul Lipid as Drug Carrier for Transdermal Drug Delivery

    PubMed Central

    Gaur, Praveen Kumar; Mishra, Shikha; Purohit, Suresh

    2013-01-01

    Diclofenac sodium loaded solid lipid nanoparticles (SLNs) were formulated using guggul lipid as major lipid component and analyzed for physical parameters, permeation profile, and anti-inflammatory activity. The SLNs were prepared using melt-emulsion sonication/low temperature-solidification method and characterized for physical parameters, in vitro drug release, and accelerated stability studies, and formulated into gel. Respective gels were compared with a commercial emulgel (CEG) and plain carbopol gel containing drug (CG) for ex vivo and in vivo drug permeation and anti-inflammatory activity. The SLNs were stable with optimum physical parameters. GMS nanoparticle 1 (GMN-1) and stearic acid nanoparticle 1 (SAN-1) gave the highest in vitro drug release. Guggul lipid nanoparticle gel 3 (GLNG-3) showed 104.68 times higher drug content than CEG in receptor fluid. The enhancement ratio of GLNG-3 was 39.43 with respect to CG. GLNG-3 showed almost 8.12 times higher Cmax than CEG at 4 hours. The AUC value of GLNG-3 was 15.28 times higher than the AUC of CEG. GLNG-3 showed edema inhibition up to 69.47% in the first hour. Physicochemical properties of major lipid component govern the properties of SLN. SLN made up of guggul lipid showed good physical properties with acceptable stability. Furthermore, it showed a controlled drug release profile along with a promising permeation profile. PMID:24058913

  5. Supercritical fluid precipitation of ketoprofen in novel structured lipid carriers for enhanced mucosal delivery - a comparison with solid lipid particles.

    PubMed

    Gonçalves, V S S; Matias, A A; Rodríguez-Rojo, S; Nogueira, I D; Duarte, C M M

    2015-11-10

    Structured lipid carriers based on mixture of solid lipids with liquid lipids are the second generation of solid lipid particles, offering the advantage of improved drug loading capacity and higher storage stability. In this study, structured lipid carriers were successfully prepared for the first time by precipitation from gas saturated solutions. Glyceryl monooleate (GMO), a liquid glycerolipid, was selected in this work to be incorporated into three solid glycerolipids with hydrophilic-lipophilic balance (HLB) ranging from 1 to 13, namely Gelucire 43/01™, Geleol™ and Gelucire 50/13™. In general, microparticles with a irregular porous morphology and a wide particle size distribution were obtained. The HLB of the individual glycerolipids might be a relevant parameter to take into account during the processing of solid:liquid lipid blends. As expected, the addition of a liquid lipid into a solid lipid matrix led to increased stability of the lipid carriers, with no significant modifications in their melting enthalpy after 6 months of storage. Additionally, Gelucire 43/01™:GMO particles were produced with different mass ratios and loaded with ketoprofen. The drug loading capacity of the structured lipid carriers increased as the GMO content in the particles increased, achieving a maximum encapsulation efficiency of 97% for the 3:1 mass ratio. Moreover, structured lipid carriers presented an immediate release of ketoprofen from its matrix with higher permeation through a mucous-membrane model, while solid lipid particles present a controlled release of the drug with less permeation capacity. PMID:26277371

  6. Lipid A as a Drug Target and Therapeutic Molecule

    PubMed Central

    Joo, Sang Hoon

    2015-01-01

    In this review, lipid A, from its discovery to recent findings, is presented as a drug target and therapeutic molecule. First, the biosynthetic pathway for lipid A, the Raetz pathway, serves as a good drug target for antibiotic development. Several assay methods used to screen for inhibitors of lipid A synthesis will be presented, and some of the promising lead compounds will be described. Second, utilization of lipid A biosynthetic pathways by various bacterial species can generate modified lipid A molecules with therapeutic value. PMID:26535075

  7. Multiscale molecular modeling of tertiary supported lipid bilayers

    NASA Astrophysics Data System (ADS)

    Ranz, Holden T.; Faller, Roland

    2015-08-01

    Ternary lipid bilayer systems assembled from mixtures of dipalmitoylphosphatidylcholine (DPPC), dioleoylphosphatidylcholine (DOPC), and cholesterol have been studied using coarse-grained molecular dynamics at biologically relevant temperatures (280 K to 310 K), which are between the chain melting temperatures of the pure lipid component. Free lipid bilayers were simulated using the MARTINI model (Stage I) and a variant with water-water interactions reduced to 76% (Stage II). The latter was subsequently used for preparing supported lipid bilayer simulations (Stage III). Clustering of like lipids was observed, but the simulation timescale did not yield larger phaseseparated domains.

  8. Lipid raft: A floating island of death or survival

    SciTech Connect

    George, Kimberly S.; Department of Chemistry, Marietta College, Marietta, OH 45750 ; Wu, Shiyong

    2012-03-15

    Lipid rafts are microdomains of the plasma membrane enriched in cholesterol and sphingolipids, and play an important role in the initiation of many pharmacological agent-induced signaling pathways and toxicological effects. The structure of lipid rafts is dynamic, resulting in an ever-changing content of both lipids and proteins. Cholesterol, as a major component of lipid rafts, is critical for the formation and configuration of lipid raft microdomains, which provide signaling platforms capable of activating both pro-apoptotic and anti-apoptotic signaling pathways. A change of cholesterol level can result in lipid raft disruption and activate or deactivate raft-associated proteins, such as death receptor proteins, protein kinases, and calcium channels. Several anti-cancer drugs are able to suppress growth and induce apoptosis of tumor cells through alteration of lipid raft contents via disrupting lipid raft integrity. -- Highlights: ? The role of lipid rafts in apoptosis ? The pro- and anti-apoptotic effects of lipid raft disruption ? Cancer treatments targeting lipid rafts.

  9. Lipidic nanovesicles stabilize suspensions of metal oxide nanoparticles.

    PubMed

    Jiménez-Rojo, Noemi; Lete, Marta G; Rojas, Elena; Gil, David; Valle, Mikel; Alonso, Alicia; Moya, Sergio E; Goñi, Félix M

    2015-10-01

    We have studied the effect of adding lipid nanovesicles (liposomes) on the aggregation of commercial titanium oxide (TiO2), zinc oxide (ZnO), or cerium oxide (CeO2) nanoparticles (NPs) suspensions in Hepes buffer. Liposomes were prepared with pure phospholipids or mixtures of phospholipids and/or cholesterol. Changes in turbidity were recorded as a function of time, either of metal nanoparticles alone, or for a mixture of nanoparticles and lipidic nanovesicles. Lipid nanovesicles markedly decrease the NPs tendency to sediment irrespective of size or lipid compositions, thus keeping the metal oxide NPs in suspension. Cryo-electron microscopy, fluorescence anisotropy of TMA-DPH and general polarization of laurdan failed to reveal any major effect of the NPs on the lipid bilayer structure or phase state of the lipids. The above data may help in developing studies of the interaction of inhaled particles with lung surfactant lipids and alveolar macrophages. PMID:26301898

  10. Lipid oxidation induced oxidative degradation of cereal beta-glucan.

    PubMed

    Wang, Yu-Jie; Mäkelä, Noora; Maina, Ndegwa Henry; Lampi, Anna-Maija; Sontag-Strohm, Tuula

    2016-04-15

    In food systems, lipid oxidation can cause oxidation of other molecules. This research for the first time investigated oxidative degradation of ?-glucan induced by lipid oxidation using an oil-in-water emulsion system which simulated a multi-phased aqueous food system containing oil and ?-glucan. Lipid oxidation was monitored using peroxide value and hexanal production while ?-glucan degradation was evaluated by viscosity and molecular weight measurements. The study showed that while lipid oxidation proceeded, ?-glucan degradation occurred. Emulsions containing ?-glucan, oil and ferrous ion showed significant viscosity and molecular weight decrease after 1week of oxidation at room temperature. Elevated temperature (40°C) enhanced the oxidation reactions causing higher viscosity drop. In addition, the presence of ?-glucan appeared to retard the hexanal production in lipid oxidation. The study revealed that lipid oxidation may induce the degradation of ?-glucan in aqueous food systems where ?-glucan and lipids co-exist. PMID:26675874

  11. Structure of a lipid-bound Extended-Synaptotagmin indicates a role in lipid transfer

    PubMed Central

    Schauder, Curtis M.; Wu, Xudong; Saheki, Yasunori; Narayanaswamy, Pradeep; Torta, Federico; Wenk, Markus R.; De Camilli, Pietro; Reinisch, Karin M.

    2014-01-01

    Growing evidence suggests that close appositions between the endoplasmic reticulum (ER) and other membranes, including appositions with the plasma membrane (PM), mediate exchange of lipids between the two bilayers. The mechanisms of such exchange, which allows lipid transfer independently of vesicular transport, remain poorly understood. The presence of an SMP (synaptotagmin-like-mitochondrial-lipid binding protein) domain, a proposed lipid binding module, in several proteins localized at membrane contact sites raised the possibility that such domains may be implicated in lipid transport1,2. SMP-containing proteins include components of the ERMES complex, an ER-mitochondrial tether3, and the Extended-Synaptotagmins/tricalbins, which are ER-PM tethers4-6. Here we present at 2.44 Å resolution the crystal structure of a fragment of Extended-Synaptotagmin 2 (E-Syt2), including an SMP domain and two adjacent C2 domains. The SMP domain has a beta-barrel structure like protein modules in the TULIP superfamily. It dimerizes to form a ~90 Å long cylinder traversed by a channel lined entirely with hydrophobic residues, with the two C2A-C2B fragments forming arched structures flexibly linked to the SMP domain. Importantly, structural analysis complemented by mass spectrometry revealed the presence of glycerophospholipids in the E-Syt2 SMP channel, indicating a direct role for E-Syts in lipid transport. These findings provide strong evidence for a role of SMP domain containing proteins in the control of lipid transfer at membrane contact sites and have broad implication beyond the field of ER to PM appositions. PMID:24847877

  12. Radiation induced lipid peroxidation in liposomes

    NASA Astrophysics Data System (ADS)

    Kale, R. K.; Sitasawad, Sandhya L.

    Liposomes prepared from L-?-lecithin were irradiated to different doses of radiation (0-660 Gy) at the dose rate 1.109 Gy s -1. Lipid peroxidation was found to increase with radiation dose up to 330 Gy and decrease with dose beyond 330 Gy. This suggests that in low dose region (0-330 Gy) most of the energy deposited into liposomes is translated into damage. On the other hand energy deposited in higher dose region (396-660 Gy) may not have completely translated into damage and some part of it might have dissipated to recombination process of free radicals resulting into formation of relatively stable and unreactive molecular products. Observation with different concentrations of liposomes, inhibition of peroxidation by catalase, enhancement by Fe 2+-ions and inverse dose rate effect indicate indirectly the occurence of recombination processes. The decrease in lipid peroxidation might also be due to the avoidance of propagation step.

  13. Jumping acoustic bubbles on lipid bilayers.

    PubMed

    Der Loughian, Christelle; Muleki Seya, Pauline; Pirat, Christophe; Inserra, Claude; Béra, Jean-Christophe; Rieu, Jean-Paul

    2015-05-01

    In the context of sonoporation, we use supported lipid bilayers as a model for biological membranes and investigate the interactions between the bilayer and microbubbles induced by ultrasound. Among the various types of damage caused by bubbles on the surface, our experiments exhibit a singular dynamic interaction process where bubbles are jumping on the bilayer, forming a necklace pattern of alteration on the membrane. This phenomenon was explored with different time and space resolutions and, based on our observations, we propose a model for a microbubble subjected to the combined action of van der Waals, acoustic and hydrodynamic forces. Describing the repeated jumps of the bubble, this model explains the lipid exchanges between the bubble and bilayer. PMID:25799328

  14. Ageing mechanisms and associated lipid changes.

    PubMed

    Kolovou, Genovefa; Katsiki, Niki; Pavlidis, Antonis; Bilianou, Helen; Goumas, George; Mikhailidis, Dimitri P

    2014-01-01

    Ageing is related to slowdown/breakdown of the somatotropic axis (i.e. the somatopause) leading to many physiological changes. The somatopause is accompanied by DNA and other macromolecule damage, and is characterized by a progressive decline in vitality and tissue function. We still do not have a definitive understanding of the mechanism( s) of ageing. Several overlapping theories have been proposed such as: 1) The free radical theory, 2) Mitochondrial Ageing, 3) The Glycation Theory, 4) Protein Damage and Maintenance in Ageing, and, 5) DNA Damage and Repair. Furthermore, several models of ageing were introduced such as genetically programmed senescence, telomere shortening, genomic instability, heterochromatin loss, altered epigenetic patterns and long lived cells. There are certain lipid modifications associated with the somatopause, characterized mainly by an increase in total cholesterol and triglyceride levels in both genders. In this review we consider the mechanisms of ageing and the associated changes in lipid metabolism according to gender. PMID:24350931

  15. The role of lipids in mechanosensation.

    PubMed

    Pliotas, Christos; Dahl, A Caroline E; Rasmussen, Tim; Mahendran, Kozhinjampara R; Smith, Terry K; Marius, Phedra; Gault, Joseph; Banda, Thandiwe; Rasmussen, Akiko; Miller, Samantha; Robinson, Carol V; Bayley, Hagan; Sansom, Mark S P; Booth, Ian R; Naismith, James H

    2015-12-01

    The ability of proteins to sense membrane tension is pervasive in biology. A higher-resolution structure of the Escherichia coli small-conductance mechanosensitive channel MscS identifies alkyl chains inside pockets formed by the transmembrane helices (TMs). Purified MscS contains E. coli lipids, and fluorescence quenching demonstrates that phospholipid acyl chains exchange between bilayer and TM pockets. Molecular dynamics and biophysical analyses show that the volume of the pockets and thus the number of lipid acyl chains within them decreases upon channel opening. Phospholipids with one acyl chain per head group (lysolipids) displace normal phospholipids (with two acyl chains) from MscS pockets and trigger channel opening. We propose that the extent of acyl-chain interdigitation in these pockets determines the conformation of MscS. When interdigitation is perturbed by increased membrane tension or by lysolipids, the closed state becomes unstable, and the channel gates. PMID:26551077

  16. Content of lipids in finnish peat mires

    SciTech Connect

    Fagernaes, L.; Ekman, R.

    1985-01-01

    Peat is a potential raw material for chemical products. Peat extracts, bitumens, obtained from peat with neutral organic solvents, and, in particular, their wax fractions have been of interest with regard to their substituting for other natural waxes. Yields and characteristics of peat extracts have been studied by numerous researchers and acid and saponification values, molecular weights and elements analyses have been determined since the 1930s. New analytical methods have recently been introduced and made it possible to determine the amount and detailed composition of the lipid components of peat extracts by capillary gas chromatography (GC) and mass spectrometry. The aim of this study was to determine the yield and lipid composition of extracts from peat samples collected from different mires in Finland.

  17. The Structure of Cholesterol in Lipid Rafts

    E-print Network

    Toppozini, Laura; Armstrong, Clare L; Yamani, Zahra; Kucerka, Norbert; Schmid, Friederike; Rheinstaedter, Maikel C

    2014-01-01

    Rafts, or functional domains, are transient nano- or mesoscopic structures in the plasma membrane and are thought to be essential for many cellular processes such as signal transduction, adhesion, trafficking and lipid/protein sorting. Observations of these membrane heterogeneities have proven challenging, as they are thought to be both small and short-lived. With a combination of coarse-grained molecular dynamics simulations and neutron diffraction using deuterium labeled cholesterol molecules we observe raft-like structures and determine the ordering of the cholesterol molecules in binary cholesterol-containing lipid membranes. From coarse-grained computer simulations, heterogenous membranes structures were observed and characterized as small, ordered domains. Neutron diffraction was used to study the lateral structure of the cholesterol molecules. We find pairs of strongly bound cholesterol molecules in the liquid-disordered phase, in accordance with the umbrella model. Bragg peaks corresponding to orderin...

  18. Rhomboid protease dynamics and lipid interactions

    PubMed Central

    Bondar, Ana-Nicoleta; Val, Coral del; White, Stephen H.

    2009-01-01

    Summary Intramembrane proteases, which cleave TM helices, participate in numerous biological processes encompassing all branches of life. Several crystallographic structures of Escherichia coli GlpG rhomboid protease have been determined. In order to understand GlpG dynamics and lipid interactions in a native-like environment, we have examined the molecular dynamics of wild-type and mutant GlpG in different membrane environments. The irregular shape and small hydrophobic thickness of the protein cause significant bilayer deformations that may be important for substrate entry into the active site. Hydrogen-bond interactions with lipids are paramount in protein orientation and dynamics. Mutations in the unusual L1 loop cause changes in protein dynamics and protein orientation that are relayed to the His-Ser catalytic dyad. Similarly, mutations in TM5 change the dynamics and structure of the L1 loop. These results imply that the L1 loop has an important regulatory role in proteolysis. PMID:19278654

  19. Hydrodynamic trapping of molecules in lipid bilayers.

    PubMed

    Jönsson, Peter; McColl, James; Clarke, Richard W; Ostanin, Victor P; Jönsson, Bengt; Klenerman, David

    2012-06-26

    In this work we show how hydrodynamic forces can be used to locally trap molecules in a supported lipid bilayer (SLB). The method uses the hydrodynamic drag forces arising from a flow through a conical pipette with a tip radius of 1-1.5 ?m, placed approximately 1 ?m above the investigated SLB. This results in a localized forcefield that acts on molecules protruding from the SLB, yielding a hydrodynamic trap with a size approximately given by the size of the pipette tip. We demonstrate this concept by trapping the protein streptavidin, bound to biotin receptors in the SLB. It is also shown how static and kinetic information about the intermolecular interactions in the lipid bilayer can be obtained by relating how the magnitude of the hydrodynamic forces affects the accumulation of protein molecules in the trap. PMID:22699491

  20. Micropatterning fluid lipid bilayers on solid supports.

    PubMed

    Groves, J T; Ulman, N; Boxer, S G

    1997-01-31

    Lithographically patterned grids of photoresist, aluminum oxide, or gold on oxidized silicon substrates were used to partition supported lipid bilayers into micrometer-scale arrays of isolated fluid membrane corrals. Fluorescently labeled lipids were observed to diffuse freely within each membrane corral but were confined by the micropatterned barriers. The concentrations of fluorescent probe molecules in individual corrals were altered by selective photobleaching to create arrays of fluid membrane patches with differing compositions. Application of an electric field parallel to the surface induced steady-state concentration gradients of charged membrane components in the corrals. In addition to producing patches of membrane with continuously varying composition, these gradients provide an intrinsically parallel means of acquiring information about molecular properties such as the diffusion coefficient in individual corrals. PMID:9005848

  1. Lipids as universal biomarkers of extraterrestrial life.

    PubMed

    Georgiou, Christos D; Deamer, David W

    2014-06-01

    In 1965, James Lovelock published a general statement, based on thermodynamic chemical equilibrium principles, about how to detect extant or extinct life on a planet other than Earth. Nearly 50 years later, it is possible to make such measurements with robotic missions such as current and future Mars rovers, and probes to sample icy plumes of Enceladus or Europa. We make a specific recommendation that certain characteristic patterns in the composition of lipid hydrocarbons can only result from a biological process, because the signal arises from a universal requirement related to lipid bilayer fluidity and membrane stability. Furthermore, the pattern can be preserved over millions of years, and instrumentation is already available to be incorporated into flight missions. PMID:24735484

  2. Capsinoids suppress fat accumulation via lipid metabolism

    PubMed Central

    HONG, QIN; XIA, CHEN; XIANGYING, HU; QUAN, YUAN

    2015-01-01

    Capsaicin, found in red peppers, has been reported to have anti-obesity, anti-hypertension, anti-diabetes and anti-inflammatory functions. In the present study, we determined the effect of non-pungent capsinoids on the metabolism of adipocytes. We demonstrated that capsinoids suppressed fat accumulation in vivo and in vitro in mice. Liver, the main tissue of lipid metabolism, was treated by capsinoids, and HMG-CoA reductase, CPT-1, FAT/CD36 and GLUT4 were found to be increased significantly, which demonstrated promotion of the lipid metabolism in liver and adipose tissues. In addition, by adding capsinoids, the induced adipocytes also demonstrated significantly increased levels of HMG-CoA reductase, CPT-1, FAT/CD36 and GLUT4. Oil red O staining also demonstrated that capsinoids decreased fat accumulation in the adipocytes. In conclusion, these results indicate that capsinoids may be worth investigating as a potential cure for obesity. PMID:25421144

  3. Membrane lipids and the origin of life

    NASA Technical Reports Server (NTRS)

    Oro, J.; Holzer, G.; Rao, M.; Tornabene, T. G.

    1981-01-01

    The current state of knowledge regarding the development of biological systems is briefly reviewed. At a crucial stage concerning the evolution of such systems, the mechanisms leading to more complex structures must have evolved within the confines of a protected microenvironment, similar to those provided by the contemporary cell membranes. The major components found normally in biomembranes are phospholipids. The structure of the biomembrane is examined, and attention is given to questions concerning the availability of the structural components which are necessary in the formation of primitive lipid membranes. Two approaches regarding the study of protomembranes are discussed. The probability of obtaining ether lipids under prebiotic conditions is considered, taking into account the formation of cyclic and acyclic isoprenoids by the irradiation of isoprene with UV.

  4. Lipids, blood pressure and kidney update 2015.

    PubMed

    Banach, Maciej; Aronow, Wilbert S; Serban, Maria-Corina; Rysz, Jacek; Voroneanu, Luminita; Covic, Adrian

    2015-01-01

    The most important studies and guidelines in the topics of lipid, blood pressure and kidney published in 2015 were reviewed. In lipid research, the IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT) trial revalidated the concept "lower is better" for low density lipoprotein (LDL)-cholesterol as a target for therapy, increasing the necessity of treatment the high-risk patients to achieve LDL-C goals. After these results, ezetimibe might become the preferred additional drug in the combination therapy of lipid disorders because of oral dosage form and lower acquisition cost. However, for the statin-intolerant patients and those patients requiring essential reductions in LDL-C to achieve their goals, new therapies, including PCSK9 inhibitors remain promising drugs. In blood pressure research, American Heart Association (AHA)/American College of Cardiology (ACC) 2015 guidelines recommended a target for blood pressure below 140/90 mmHg in stable or unstable coronary artery disease patients and below 150/90 mmHg in patients older than 80 years of age, however the recent results of the Systolic Blood Pressure Intervention Trial (SPRINT) trial have suggested that there might be significant benefits, taking into account cardiovascular risk, for hypertensive patients over 50 without diabetes and blood pressure levels <120/80. In kidney research, reducing the progression of chronic kidney disease and related complications such as anemia, metabolic acidosis, bone and mineral diseases, acute kidney injury and cardiovascular disease is still a goal for clinicians. PMID:26718096

  5. Lipid peroxidation in systemic lupus erythematosus.

    PubMed

    Kurien, Biji T; Scofield, R Hal

    2006-05-01

    Lipid peroxidation is an important process in oxygen toxicity. Free radicals inflict this damage by attacking polyunsaturated fatty acids, thus setting off a deleterious chain reaction that ultimately results in their disintegration into malondialdehye, 4 hydroxy-2-nonenal and other harmful by-products. Peroxidation of lipids has been implicated in several diseases including systemic lupus erythematosus (SLE). SLE is an autoimmune disorder with unknown aetiology, characterized by the presence of autoantibodies to self-antigens. There is a significant increase in the production of free radicals like superoxide and hydroxyl radicals in SLE. Indices of lipid peroxidation, like conjugated dienes, malondialdehyde, 8-isoprostaglandin F2 alpha are significantly elevated in SLE. Increased ceruloplasmin levels and decreased transferrin levels in the sera of SLE patients have also been described. The activities of the antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase and the amounts of the antioxidant reduced glutathione are also significantly altered in this disease. In addition, there are significant changes in the essential fatty acid profile in the sera of those affected with the disease. In animal models of the disease, immunization of mice with peptides derived from autoantigens induces SLE like disease. Immunization with an oxidatively modified autoantigen led to the rapid development of autoimmunity compared to immunization with the unmodified autoantigen. Thus, oxidative damage appears to play an important role in SLE pathogenesis. PMID:16708886

  6. Clinical applications of intravenous lipid emulsion therapy.

    PubMed

    Muller, Sam H; Diaz, James H; Kaye, Alan David

    2015-12-01

    Intravenous lipid emulsion (ILE; Intralipid) therapy, a standard treatment in local anesthetic toxicity, has demonstrated therapeutic efficacies for a number of different drug class-mediated toxicities. Some of these varied drug groups include antipsychotics, antidepressants, antiarrhythmics, and calcium channel blockers. To meet the objective of describing the growing number of indications for Intralipid therapy and any diverse effects and/or failures of Intralipid therapy in reversing multiple drug toxicities, we queried several Internet search engines with the key words "intravenous lipid emulsion therapy," "Intralipid," "lipid emulsion," and "local anesthetic systemic toxicity," resulting in the identification of 31 case reports for descriptive analysis. These case reports included 49 separate drug overdose cases involving ten separate drug classes which were successfully reversed with Intralipid. The education of clinicians regarding the beneficial and varied roles of Intralipid therapy in different clinical settings is warranted, particularly in terms of the potential for Intralipid therapy to reverse the toxicities of non-local anesthetic drugs. PMID:26049929

  7. Supramolecular Protein Immobilization on Lipid Bilayers.

    PubMed

    Bosmans, Ralph P G; Hendriksen, Wouter E; Verheijden, Mark; Eelkema, Rienk; Jonkheijm, Pascal; van Esch, Jan H; Brunsveld, Luc

    2015-12-01

    Protein immobilization on surfaces, and on lipid bilayers specifically, has great potential in biomolecular and biotechnological research. Of current special interest is the immobilization of proteins using supramolecular noncovalent interactions. This allows for a reversible immobilization and obviates the use of harsh ligation conditions that could denature fragile proteins. In the work presented here, reversible supramolecular immobilization of proteins on lipid bilayer surfaces was achieved by using the host-guest interaction of the macrocyclic molecule cucurbit[8]uril. A fluorescent protein was successfully immobilized on the lipid bilayer by making use of the property of cucurbit[8]uril to host together a methylviologen and the indole of a tryptophan positioned on the N-terminal of the protein. The supramolecular complex was anchored to the bilayer through a cholesterol moiety that was attached to the methylviologen tethered with a small polyethylene glycol spacer. Protein immobilization studies using a quartz crystal microbalance (QCM) showed the assembly of the supramolecular complexes on the bilayer. Specific immobilization through the protein N-terminus is more efficient than through protein side-chain events. Reversible surface release of the proteins could be achieved by washing with cucurbit[8]uril or buffer alone. The described system shows the potential of supramolecular assembly of proteins and provides a method for site-specific protein immobilization under mild conditions in a reversible manner. PMID:26527541

  8. Intravenous lipids in home parenteral nutrition.

    PubMed

    Pironi, Loris; Agostini, Federica; Guidetti, Mariacristina

    2015-01-01

    Intravenous lipid emulsions (IVLEs) are an important component of the nutritional admixtures for patients on long-term home parenteral nutrition (HPN) for chronic intestinal failure (CIF). IVLEs are primarily used as a source of energy and essential fatty acids, and the content of polyunsaturated fatty acids (PUFAs) is the most important characteristic of IVLEs. IVLEs rich in n-6 PUFAs may have a pro-inflammatory effect, whereas those rich in n-3 PUFAs may exert an anti-inflammatory effect. Other components to be considered are the risk of lipid peroxidation and the contents of ?-tocopherol and phytosterols. Published studies were reviewed to determine the effects of the commercially available IVLEs on essential fatty acid status, liver function tests, lipid peroxidation and inflammatory indices, and ?-tocopherol status, as well as their clinical safety and efficacy in patients on HPN. Investigations on the efficacy of fish oil-based IVLEs, which are rich in n-3 PUFAs, in the treatment of parenteral nutrition-associated liver disease (PNALD) in adult patients on HPN for CIF were also analyzed. The current commercial IVLE formulations have similar clinical safety profiles and efficacies and can prevent the development of essential fatty acid deficiency in adults on HPN for CIF. IVLE with a low content of n-6 PUFAs and with or without increased n-3 PUFA content may reduce the risk of PNALD. Fish oil-based IVLE, which is rich in n-3 PUFAs, may be effective in reversing hepatic cholestasis due to PNALD. PMID:25471810

  9. Crystallizing Membrane Proteins Using Lipidic Mesophases

    PubMed Central

    Caffrey, Martin; Cherezov, Vadim

    2009-01-01

    A detailed protocol for crystallizing membrane proteins that makes use of lipidic mesophases is described. This has variously been referred to as the lipid cubic phase or in meso method. The method has been shown to be quite general in that it has been used to solve X-ray crystallographic structures of prokaryotic and eukaryotic proteins, proteins that are monomeric, homo- and hetero-multimeric, chromophore-containing and chromophore-free, and ?-helical and ?-barrel proteins. Its most recent successes are the human engineered ?2-adrenergic and adenosine A2A G protein-coupled receptors. Protocols are provided for preparing and characterizing the lipidic mesophase, for reconstituting the protein into the monoolein-based mesophase, for functional assay of the protein in the mesophase, and for setting up crystallizations in manual mode. Methods for harvesting micro-crystals are also described. The time required to prepare the protein-loaded mesophase and to set up a crystallization plate manually is about one hour. PMID:19390528

  10. Stiffened lipid platforms at molecular force foci.

    PubMed

    Anishkin, Andriy; Kung, Ching

    2013-03-26

    How mechanical forces are sensed remains largely mysterious. The forces that gate prokaryotic and several eukaryotic channels were found to come from the lipid membrane. Our survey of animal cells found that membrane force foci all have cholesterol-gathering proteins and are reinforced with cholesterol. This result is evident in overt force sensors at the tips of stereocilia for vertebrate hearing and the touch receptor of Caenorhabditis elegans and mammalian neurons. For less specialized cells, cadherins sustain the force between neighboring cells and integrins between cells and matrix. These tension bearers also pass through and bind to a cholesterol-enriched platform before anchoring to cytoskeleton through other proteins. Cholesterol, in alliance with sphingomyelin and specialized proteins, enforces a more ordered structure in the bilayer. Such a stiffened platform can suppress mechanical noise, redirect, rescale, and confine force. We speculate that such platforms may be dynamic. The applied force may allow disordered-phase lipids to enter the platform-staging channel opening in the thinner mobile neighborhood. The platform may also contain specialized protein/lipid subdomains enclosing mechanosensitive channels to open with localized tension. Such a dynamic stage can mechanically operate structurally disparate channels or enzymes without having to tie them directly to cadherin, integrin, or other protein tethers. PMID:23476066

  11. Tumor-induced alterations in lipid metabolism.

    PubMed

    Notarnicola, M; Tutino, V; Caruso, M G

    2014-01-01

    Alterations of lipid metabolism have been increasingly recognized as a hallmark of cancer cells. Cancer cells esterify fatty acids predominantly to phospholipids, an essential component of cell membranes. The main pathway along which proliferating cells gain lipids for membrane synthesis is the endogenous mevalonate pathway. Increased synthesis of mevalonate and mevalonate-derived isoprenoids supports increased cell proliferation through activating growth-regulatory proteins and oncoproteins and promoting DNA synthesis. The importance of a better knowledge of metabolic changes in lipogenic enzymes pathways, as well as of the role of each biochemical pathway in carcinogenesis, provides the rationale for in-depth study of the oncogenic signaling important for the initiation and progression of tumors. The dependence of tumor cells on a dysregulated lipid metabolism suggests that the proteins involved in this process may be excellent chemotherapeutic targets for cancer treatment. Here, we confirm the vital link between lipogenesis and cell proliferation, and our recent findings suggest that nutritional intervention is an effective and safe way to reduce cell proliferation in experimental models of carcinogenesis. The olive oil diet significantly reduces the protein activities of lipogenic enzymes associated with cell growth. The use of natural dietary components could potentially assist in the management of subjects with metabolic disorders-related tumors. PMID:24606524

  12. Microorganism lipid droplets and biofuel development.

    PubMed

    Liu, Yingmei; Zhang, Congyan; Shen, Xipeng; Zhang, Xuelin; Cichello, Simon; Guan, Hongbin; Liu, Pingsheng

    2013-12-01

    Lipid droplet (LD) is a cellular organelle that stores neutral lipids as a source of energy and carbon. However, recent research has emerged that the organelle is involved in lipid synthesis, transportation, and metabolism, as well as mediating cellular protein storage and degradation. With the exception of multi-cellular organisms, some unicellular microorganisms have been observed to contain LDs. The organelle has been isolated and characterized from numerous organisms. Triacylglycerol (TAG) accumulation in LDs can be in excess of 50% of the dry weight in some microorganisms, and a maximum of 87% in some instances. These microorganisms include eukaryotes such as yeast and green algae as well as prokaryotes such as bacteria. Some organisms obtain carbon from CO2 via photosynthesis, while the majority utilizes carbon from various types of biomass. Therefore, high TAG content generated by utilizing waste or cheap biomass, coupled with an efficient conversion rate, present these organisms as bio-tech 'factories' to produce biodiesel. This review summarizes LD research in these organisms and provides useful information for further LD biological research and microorganism biodiesel development. PMID:24355300

  13. Design of lipid microparticle dispersions based on the physicochemical properties of the lipid and aqueous phase.

    PubMed

    Lauterbach, Andreas; Müller-Goymann, Christel C

    2015-10-15

    Lipid microparticle (LMP) dispersions may be utilized as novel pharmaceutical dosage forms for different administration routes. The particle size and particle size distribution of the LMPs can be classified to the most crucial specifications for therapeutical and research applications. The size parameters can be adjusted via the physicochemical properties of the inner lipid and the outer aqueous phase. In the present study, ten different solid lipids with incorporated lecithin and four concentrations of the surfactant poloxamer 407 (P407) were utilized for LMP dispersion preparation. Physicochemical properties of the bulk and dispersed lipid matrices as well as features of the P407 solutions were determined. Correlations between the mean particle size (mean) of the LMPs and the span as parameter for the particle size distribution as responses were identified by plotting against the measured physicochemical parameters. Most significant linear correlations were found between the mean and the micellization onset temperature (Tmicell) in the parent solution and the dynamic viscosity of the emulsifier solution at 25 °C and between the span and the Tmicell in the LMP dispersion. Consequently, P407 micelles as a reservoir for surfactant monomers and the overall viscosity as a separator between newly-formed lipid droplets are fundamental stabilizing parameters. PMID:26315123

  14. Enzymatic production of biodiesel from Nannochloropsis gaditana lipids: Influence of operational variables and polar lipid content.

    PubMed

    Navarro López, Elvira; Robles Medina, Alfonso; González Moreno, Pedro A; Jiménez Callejón, María J; Esteban Cerdán, Luis; Martín Valverde, Lorena; Castillo López, Beatriz; Molina Grima, Emilio

    2015-07-01

    Fatty acid methyl esters (FAMEs, biodiesel) were produced from Nannochloropsis gaditana wet biomass (12% saponifiable lipids, SLs) by extraction of SLs and lipase catalyzed transesterification. Lipids were extracted by ethanol (96%)-hexane, and 31% pure SLs were obtained with 85% yield. When the lipids were degummed, SL purity increased to 95%. Novozym 435 was selected from four lipases tested. Both the lipidic composition and the use of t-butanol instead of hexane increased the reaction velocity and the conversion, since both decreased due to the adsorption of polar lipids on the lipase immobilization support. The best FAME yield (94.7%) was attained at a reaction time of 48h and using 10mL of t-butanol/g SL, 0.225gN435/g SL, 11:1 methanol/SL molar ratio and adding the methanol in three steps. In these conditions the FAME conversion decreased by 9.8% after three reaction cycles catalyzed by the same lipase batch. PMID:25863898

  15. Zebrafish yolk lipid processing: a tractable tool for the study of vertebrate lipid transport and metabolism

    PubMed Central

    Miyares, Rosa L.; de Rezende, Vitor B.; Farber, Steven A.

    2014-01-01

    Dyslipidemias are a major cause of morbidity and mortality in the world, particularly in developed nations. Investigating lipid and lipoprotein metabolism in experimentally tractable animal models is a crucial step towards understanding and treating human dyslipidemias. The zebrafish, a well-established embryological model, is emerging as a notable system for studies of lipid metabolism. Here, we describe the value of the lecithotrophic, or yolk-metabolizing, stages of the zebrafish as a model for studying lipid metabolism and lipoprotein transport. We demonstrate methods to assay yolk lipid metabolism in embryonic and larval zebrafish. Injection of labeled fatty acids into the zebrafish yolk promotes efficient uptake into the circulation and rapid metabolism. Using a genetic model for abetalipoproteinemia, we show that the uptake of labeled fatty acids into the circulation is dependent on lipoprotein production. Furthermore, we examine the metabolic fate of exogenously delivered fatty acids by assaying their incorporation into complex lipids. Moreover, we demonstrate that this technique is amenable to genetic and pharmacologic studies. PMID:24812437

  16. Reversible Effects of Peptide Concentration and Lipid Composition on H-Ras Lipid Anchor Clustering.

    PubMed

    Lin, Xubo; Li, Zhenlong; Gorfe, Alemayehu A

    2015-12-15

    Dynamic clusters of lipid-anchored Ras proteins are important for high-fidelity signal transduction in cells. The average size of Ras nanoclusters was reported to be independent of protein expression levels, and cholesterol depletion is commonly used to test the raft-preference of nanoclusters. However, whether protein concentration and membrane domain stability affect Ras clustering in a reversible manner is not well understood. We used coarse-grained molecular dynamics simulations to examine the reversibility of the effects of peptide and cholesterol concentrations as well as a lipid domain-perturbing nanoparticle (C60) on the dynamics and stability of H-Ras lipid-anchor nanoclusters. By comparing results from these simulations with previous observations from the literature, we show that effects of peptide/cholesterol concentrations on the dynamics and stability of H-Ras peptide nanoclusters are reversible. Our results also suggest a correlation between the stabilities of lipid domains and Ras nanoclusters, which is supported by our finding that C60 penetrates into the liquid-disordered domain of the bilayer, destabilizing lipid domains and thereby the stability of the nanoclusters. PMID:26682805

  17. 2013 PLANT LIPIDS GORDON RESEARCH CONFERENCE AND GORDON RESEARCH SEMINAR (JANUARY 27-FEBRUARY 1, 2013 - HOTEL GALVEZ, GALVESTON TX)

    SciTech Connect

    Welti, Ruth

    2012-11-01

    Presenters will discuss the latest advances in plant and algal lipid metabolism, oil synthesis, lipid signaling, lipid visualization, lipid biotechnology and its applications, the physiological and developmental roles of lipids, and plant lipids in health. Sessions include: Producing Nutritional Lipids; Metabolic biochemistry in the next decade; Triacylglycerols: Metabolism, function, and as a target for engineering; Lipids in Protection, Reproduction, and Development; Genetic and Lipidomic Approaches to Understanding Lipid Metabolism and Signaling; Lipid Signaling in Stress Responses; New Insights on the Path to Triacylglycerols; Membrane Lipid Signaling; Lipid Visualization; Development of Biofuels and Industrial Lipids.

  18. Analysis of Lipoplex Structure and Lipid Phase Changes

    SciTech Connect

    Koynova, Rumiana

    2012-07-18

    Efficient delivery of genetic material to cells is needed for tasks of utmost importance in the laboratory and clinic, such as gene transfection and gene silencing. Synthetic cationic lipids can be used as delivery vehicles for nucleic acids and are now considered the most promising nonviral gene carriers. They form complexes (lipoplexes) with the polyanionic nucleic acids. A critical obstacle for clinical application of the lipid-mediated DNA delivery (lipofection) is its unsatisfactory efficiency for many cell types. Understanding the mechanism of lipid-mediated DNA delivery is essential for their successful application, as well as for a rational design and synthesis of novel cationic lipoid compounds for enhanced gene delivery. A viewpoint now emerging is that the critical factor in lipid-mediated transfection is the structural evolution of lipoplexes within the cell, upon interacting and mixing with cellular lipids. In particular, recent studies showed that the phase evolution of lipoplex lipids upon interaction and mixing with membrane lipids appears to be decisive for transfection success: specifically, lamellar lipoplex formulations, which were readily susceptible to undergoing lamellar-nonlamellar phase transition upon mixing with cellular lipids and were found rather consistently associated with superior transfection potency, presumably as a result of facilitated DNA release. Thus, understanding the lipoplex structure and the phase changes upon interacting with membrane lipids is important for the successful application of the cationic lipids as gene carriers.

  19. Lipid Quality in Infant Nutrition: Current Knowledge and Future Opportunities.

    PubMed

    Delplanque, Bernadette; Gibson, Robert; Koletzko, Berthold; Lapillonne, Alexandre; Strandvik, Birgitta

    2015-07-01

    Dietary lipids are key for infants to not only meet their high energy needs but also fulfill numerous metabolic and physiological functions critical to their growth, development, and health. The lipid composition of breast milk varies during lactation and according to the mother's diet, whereas the lipid composition of infant formulae varies according to the blend of different fat sources. This report compares the compositions of lipids in breast milk and infant formulae, and highlights the roles of dietary lipids in term and preterm infants and their potential biological and health effects. The major differences between breast milk and formulae lie in a variety of saturated fatty acids (such as palmitic acid, including its structural position) and unsaturated fatty acids (including arachidonic acid and docosahexaenoic acid), cholesterol, and complex lipids. The functional outcomes of these differences during infancy and for later child and adult life are still largely unknown, and some of them are discussed, but there is consensus that opportunities exist for improvements in the qualitative lipid supply to infants through the mother's diet or infant formulae. Furthermore, research is required in several areas, including the needs of term and preterm infants for long-chain polyunsaturated fatty acids, the sites of action and clinical effects of lipid mediators on immunity and inflammation, the role of lipids on metabolic, neurological, and immunological outcomes, and the mechanisms by which lipids act on short- and long-term health. PMID:25883056

  20. Composition Based Strategies for Controlling Radii in Lipid Nanotubes

    PubMed Central

    Kurczy, Michael E.; Mellander, Lisa J.; Najafinobar, Neda; Cans, Ann-Sofie

    2014-01-01

    Nature routinely carries out small-scale chemistry within lipid bound cells and organelles. Liposome–lipid nanotube networks are being developed by many researchers in attempt to imitate these membrane enclosed environments, with the goal to perform small-scale chemical studies. These systems are well characterized in terms of the diameter of the giant unilamellar vesicles they are constructed from and the length of the nanotubes connecting them. Here we evaluate two methods based on intrinsic curvature for adjusting the diameter of the nanotube, an aspect of the network that has not previously been controllable. This was done by altering the lipid composition of the network membrane with two different approaches. In the first, the composition of the membrane was altered via lipid incubation of exogenous lipids; either with the addition of the low intrinsic curvature lipid soy phosphatidylcholine (soy-PC) or the high intrinsic curvature lipid soy phosphatidylethanolamine (soy-PE). In the second approach, exogenous lipids were added to the total lipid composition during liposome formation. Here we show that for both lipid augmentation methods, we observed a decrease in nanotube diameter following soy-PE additions but no significant change in size following the addition of soy-PC. Our results demonstrate that the effect of soy-PE on nanotube diameter is independent of the method of addition and suggests that high curvature soy-PE molecules facilitate tube membrane curvature. PMID:24392077

  1. Perilipin-related protein regulates lipid metabolism in C. elegans

    PubMed Central

    Chughtai, Ahmed Ali; Kaššák, Filip; Kostrouchová, Markéta; Novotný, Jan Philipp; Krause, Michael W.; Kostrouch, Zdenek

    2015-01-01

    Perilipins are lipid droplet surface proteins that contribute to fat metabolism by controlling the access of lipids to lipolytic enzymes. Perilipins have been identified in organisms as diverse as metazoa, fungi, and amoebas but strikingly not in nematodes. Here we identify the protein encoded by the W01A8.1 gene in Caenorhabditis elegans as the closest homologue and likely orthologue of metazoan perilipin. We demonstrate that nematode W01A8.1 is a cytoplasmic protein residing on lipid droplets similarly as human perilipins 1 and 2. Downregulation or elimination of W01A8.1 affects the appearance of lipid droplets resulting in the formation of large lipid droplets localized around the dividing nucleus during the early zygotic divisions. Visualization of lipid containing structures by CARS microscopy in vivo showed that lipid-containing structures become gradually enlarged during oogenesis and relocate during the first zygotic division around the dividing nucleus. In mutant embryos, the lipid containing structures show defective intracellular distribution in subsequent embryonic divisions and become gradually smaller during further development. In contrast to embryos, lipid-containing structures in enterocytes and in epidermal cells of adult animals are smaller in mutants than in wild type animals. Our results demonstrate the existence of a perilipin-related regulation of fat metabolism in nematodes and provide new possibilities for functional studies of lipid metabolism. PMID:26357594

  2. Multiscale Modeling of Supported Lipid Bilayers

    NASA Astrophysics Data System (ADS)

    Hoopes, Matthew I.; Xing, Chenyue; Faller, Roland

    Cell membranes consist of a multitude of lipid molecules that serve as a framework for the even greater variety of membrane associated proteins [1-4]. As this highly complex (nonequilibrium) system cannot easily be understood and studied in a controlled way, a wide variety of model systems have been devised to understand the dynamics, structure, and thermodynamics in biological membranes. One such model system is a supported lipid bilayer (SLB), a two-dimensional membrane suspended on a surface. SLBs have been realized to be manageable experimentally while reproducing many of the key features of real biological membranes [5,6]. One of the main advantages of supported bilayers is the physical stability due to the solid support that enables a wide range of surface characterization techniques not available to free or unsupported membranes. As SLBs maintain some of the crucial structural and dynamic properties of biological membranes, they provide an important bridge to natural systems. In order to mimic cell membranes reliably, certain structural and dynamic features have to be reliably reproduced in the artificially constructed lipid bilayers. SLBs should display lateral mobility as in living cells, because many membrane activities involve transport, recruitment, or assembly of specific components. It is also critical for membranes to exhibit the correct thermodynamic phase, namely, a fluid lipid bilayer, to respond to environmental stress such as temperature and pressure changes [7]. There are several ways to fabricate supported lipid bilayers (SLBs) on planar substrates. One can use vesicle fusion on solid substrates [5,8-10] as well as Langmuir-Blodgett deposition [11,12]. Proteoliposome adsorption and subsequent membrane formation on a mica surface was first demonstrated by Brian and McConnell [13]. Because of its simplicity and reproducibility, this is one of the most common approaches to prepare supported membranes. A diverse range of different solid substrates has been used as support material below the bilayer [14,15]. Silicon oxide is the material of choice for vesicle fusion [16]. Polymer cushions dampen the effect of hard surfaces and therefore have been actively investigated [17-20]. However, it is not fully understood which changes the introduction of a solid support introduces into such a biomimetic system. Experimentally it is almost impossible to address such changes, as extremely highresolution data would be required.

  3. Lipids around the Clock: Focus on Circadian Rhythms and Lipid Metabolism

    PubMed Central

    Gnocchi, Davide; Pedrelli, Matteo; Hurt-Camejo, Eva; Parini, Paolo

    2015-01-01

    Disorders of lipid and lipoprotein metabolism and transport are responsible for the development of a large spectrum of pathologies, ranging from cardiovascular diseases, to metabolic syndrome, even to tumour development. Recently, a deeper knowledge of the molecular mechanisms that control our biological clock and circadian rhythms has been achieved. From these studies it has clearly emerged how the molecular clock tightly regulates every aspect of our lives, including our metabolism. This review analyses the organisation and functioning of the circadian clock and its relevance in the regulation of physiological processes. We also describe metabolism and transport of lipids and lipoproteins as an essential aspect for our health, and we will focus on how the circadian clock and lipid metabolism are greatly interconnected. Finally, we discuss how a deeper knowledge of this relationship might be useful to improve the recent spread of metabolic diseases. PMID:25665169

  4. Zinc Regulates Lipid Metabolism and MMPs Expression in Lipid Disturbance Rabbits.

    PubMed

    Xu, Chenggui; Huang, Zhibin; Liu, Lijuan; Luo, Chufan; Lu, Guihua; Li, Qinglang; Gao, Xiuren

    2015-12-01

    Lipid disturbance induced by high-fat diet is a worldwide problem, and it can induce inflammation and oxidative stress in vivo. Zinc is considered as an antioxidant, anti-inflammatory agent. Since matrix metalloprotease 2 (MMP2) and matrix metalloprotease 9 (MMP9)'s expressions are changed under many pathological conditions, we would like to know how zinc affects lipid metabolism and MMP2, MMP9's expressions in the lipid disturbance rabbits. Twenty-four male New Zealand white rabbits were randomly divided into four groups. Each group had six rabbits, and they were fed with regular diet, high-fat diet, high-fat diet + zinc, and regular diet + zinc separately for 12 weeks. High-fat diet induced lipid disturbance significantly which raised the level of aspartate aminotransferase (p??0.05), but it lowered triglyceride (TG) and raised high-density lipoprotein cholesterol (HDL-C) (p?lipid disturbance rabbits. Zinc protected the liver, reduced TG, hs-CRP, and IL-6 and raised HDL-C in the lipid disturbance rabbits. Zinc suppressed MMP2 and MMP9's expressions in vivo, but it did not alleviate the severity of aorta fatty streak induced by the high-fat diet. PMID:25987270

  5. Response of pigeon guillemots to variable abundance of high-lipid and low-lipid prey

    USGS Publications Warehouse

    Litzow, M.A.; Piatt, J.F.; Prichard, A.K.; Roby, D.D.

    2002-01-01

    Populations of the pigeon guillemot (Cepphus columba) and other piscivores have been in decline for several decades in the Gulf of Alaska and Bering Sea, and a decline in abundance of lipid-rich schooling fishes is hypothesized as the major cause. We tested this hypothesis by studying the breeding biology of pigeon guillemots during 1995-1999 while simultaneously measuring prey abundance with beach seines and bottom trawls. Our study area (Kachemak Bay, Alaska) comprises two oceanographically distinct areas. Populations of a lipid-rich schooling fish, Pacific sand lance (Ammodytes hexapterus), were higher in the warmer Inner Bay than in the colder Outer Bay, and sand lance abundance was higher during warm years. Populations of low-lipid content demersal fishes were similar between areas. Chick survival to age 15 days was 47% higher in the Inner Bay (high-lipid diet) than in the Outer Bay (low-lipid diet), and estimated reproductive success (chicks fledged nest-1) was 62% higher in the Inner Bay than in the Outer Bay. Chick provisioning rate (kJ chick-1 h-1) increased with the proportion of sand lance in the diet (r2=0.21), as did growth rate (g day-1) of younger (beta) chicks in two-chick broods (r2=0.14). Pigeon guillemots in the Inner Bay switched to demersal prey during years of below-average sand lance abundance, and these birds reacted to 38-fold interannual changes in sand lance abundance with reductions in beta chick growth rates, with no decline in beta chick survival. In contrast, the proportion of nests experiencing brood reduction in the Outer Bay (demersal diet) increased >300% during years of below-average demersal abundance, although demersal fish abundance varied only 4-fold among years. Our results support the hypothesis that recovery of pigeon guillemot populations from the effects of the Exxon Valdez oil spill is limited by availability of lipid-rich prey.

  6. Lipid and lipid mediator profiling of human synovial fluid in rheumatoid arthritis patients by means of LC-MS/MS.

    PubMed

    Giera, Martin; Ioan-Facsinay, Andreea; Toes, Rene; Gao, Fei; Dalli, Jesmond; Deelder, André M; Serhan, Charles N; Mayboroda, Oleg A

    2012-11-01

    Human synovial fluid (SF) provides nutrition and lubrication to the articular cartilage. Particularly in arthritic diseases, SF is extensively accumulating in the synovial junction. During the last decade lipids have attracted considerable attention as their role in the development and resolution of diseases became increasingly recognized. Here, we describe a capillary LC-MS/MS screening platform that was used for the untargeted screening of lipids present in human SF of rheumatoid arthritis (RA) patients. Using this platform we give a detailed overview of the lipids and lipid-derived mediators present in the SF of RA patients. Almost 70 different lipid components from distinct lipid classes were identified and quantification was achieved for the lysophosphatidylcholine and phosphatidylcholine species. In addition, we describe a targeted LC-MS/MS lipid mediator metabolomics strategy for the detection, identification and quantification of maresin 1, lipoxin A(4) and resolvin D5 in SF from RA patients. Additionally, we present the identification of 5S,12S-diHETE as a major marker of lipoxygenase pathway interactions in the investigated SF samples. These results are the first to provide a comprehensive approach to the identification and profiling of lipids and lipid mediators present in SF and to describe the presence of key anti-inflammatory and pro-resolving lipid mediators identified in SF from RA patients. PMID:22841830

  7. Synthesis and characterization of a lipidic alpha amino acid: solubility and interaction with serum albumin and lipid bilayers.

    PubMed

    Filipe, Hugo A L; Coreta-Gomes, Filipe M; Velazquez-Campoy, Adrian; Almeida, Ana R; Peixoto, Andreia F; Pereira, Mariette M; Vaz, Winchil L C; Moreno, Maria J

    2013-04-01

    The lipidic ?-amino acid with 11 carbons in the alkyl lateral chain (?-aminotridecanoic acid) was synthesized via multicomponent hydroformylation/Strecker reaction, which is a greener synthetic approach to promote this transformation relative to previously described methods. Its solubility and aggregation behavior in aqueous solutions was characterized, as well as the interaction with lipid bilayers. Lipidic amino acids are very promising molecules in the development of prodrugs with increased bioavailability due to the presence of the two polar functional groups and nonpolar alkyl chain. They are also biocompatible surfactants that may be used in the food and pharmaceutical industry. In this work we have conjugated the lipidic amino acid with a fluorescent polar group (7-nitrobenz-2-oxa-1,3-diazol-4-yl), to mimic drug conjugates, and its association with serum proteins and lipid bilayers was characterized. The results obtained indicate that conjugates of polar molecules with lipidic ?-amino acid, via covalent attachment to the amine group, have a relatively high solubility in aqueous solutions due to their negative global charge. They bind to serum albumin with intermediate affinity and show a very high partition coefficient into lipid bilayers in the liquid-disordered state. The attachment of the polar group to the lipidic amino acid increased strongly the aqueous solubility of the amphiphile, although the partition coefficient into lipid membranes was not significantly reduced. Conjugation of polar drugs with lipidic amino acids is therefore an efficient approach to increase their affinity for biomembranes. PMID:23477590

  8. Lipid and lipid mediator profiling of human synovial fluid in rheumatoid arthritis patients by means of LC-MS/MS

    PubMed Central

    Giera, Martin; Ioan-Facsinay, Andreea; Toes, Rene; Gao, Fei; Dalli, Jesmond; Deelder, Andre M; Serhan, Charles N; Mayboroda, Oleg A

    2012-01-01

    Human synovial fluid (SF) provides nutrition and lubrication to the articular cartilage. Particularly in arthritic diseases, SF is extensively accumulating in the synovial junction. During the last decade lipids have attracted considerable attention as their role in the development and resolution of diseases became increasingly recognized. Here, we describe a capillary LC-MS/MS screening platform that was used for the untargeted screening of lipids present in human SF of rheumatoid arthritis (RA) patients. Using this platform we give a detailed overview of the lipids and lipid – derived mediators present in the SF of RA patients. Almost 70 different lipid components from distinct lipid classes were identified and quantification was achieved for the lysophosphatidylcholine and phosphatidylcholine species. In addition, we describe a targeted LC-MS/MS lipid mediator metabolomics strategy for the detection, identification and quantification of maresin 1, lipoxin A4 and resolvin D5 in SF from RA patients. Additionally, we present the identification of 5S,12S-diHETE as a major marker of lipoxygenase pathway interactions in the investigated SF samples. These results are the first to provide a comprehensive approach to the identification and profiling of lipids and lipid mediators present in SF and to describe the presence of key anti-inflammatory and pro-resolving lipid mediators identified in SF from RA patients. PMID:22841830

  9. Characterization of Horizontal Lipid Bilayers as a Model System to Study Lipid Phase Separation

    PubMed Central

    Honigmann, Alf; Walter, Claudius; Erdmann, Frank; Eggeling, Christian; Wagner, Richard

    2010-01-01

    Abstract Artificial lipid membranes are widely used as a model system to study single ion channel activity using electrophysiological techniques. In this study, we characterize the properties of the artificial bilayer system with respect to its dynamics of lipid phase separation using single-molecule fluorescence fluctuation and electrophysiological techniques. We determined the rotational motions of fluorescently labeled lipids on the nanosecond timescale using confocal time-resolved anisotropy to probe the microscopic viscosity of the membrane. Simultaneously, long-range mobility was investigated by the lateral diffusion of the lipids using fluorescence correlation spectroscopy. Depending on the solvent used for membrane preparation, lateral diffusion coefficients in the range Dlat = 10–25 ?m2/s and rotational diffusion coefficients ranging from Drot = 2.8 ? 1.4 × 107 s?1 were measured in pure liquid-disordered (Ld) membranes. In ternary mixtures containing saturated and unsaturated phospholipids and cholesterol, liquid-ordered (Lo) domains segregated from the Ld phase at 23°C. The lateral mobility of lipids in Lo domains was around eightfold lower compared to those in the Ld phase, whereas the rotational mobility decreased by a factor of 1.5. Burst-integrated steady-state anisotropy histograms, as well as anisotropy imaging, were used to visualize the rotational mobility of lipid probes in phase-separated bilayers. These experiments and fluorescence correlation spectroscopy measurements at different focal diameters indicated a heterogeneous microenvironment in the Lo phase. Finally, we demonstrate the potential of the optoelectro setup to study the influence of lipid domains on the electrophysiological properties of ion channels. We found that the electrophysiological activity of gramicidin A (gA), a well-characterized ion-channel-forming peptide, was related to lipid-domain partitioning. During liquid-liquid phase separation, gA was largely excluded from Lo domains. Simultaneously, the number of electrically active gA dimers increased due to the increased surface density of gA in the Ld phase. PMID:20550901

  10. Insect endosymbiont proliferation is limited by lipid availability.

    PubMed

    Herren, Jeremy K; Paredes, Juan C; Schüpfer, Fanny; Arafah, Karim; Bulet, Philippe; Lemaitre, Bruno

    2014-01-01

    Spiroplasma poulsonii is a maternally transmitted bacterial endosymbiont that is naturally associated with Drosophila melanogaster. S. poulsonii resides extracellularly in the hemolymph, where it must acquire metabolites to sustain proliferation. In this study, we find that Spiroplasma proliferation specifically depletes host hemolymph diacylglyceride, the major lipid class transported by the lipoprotein, Lpp. RNAi-mediated knockdown of Lpp expression, which reduces the amount of circulating lipids, inhibits Spiroplasma proliferation demonstrating that bacterial proliferation requires hemolymph-lipids. Altogether, our study shows that an insect endosymbiont acquires specific lipidic metabolites from the transport lipoproteins in the hemolymph of its host. In addition, we show that the proliferation of this endosymbiont is limited by the availability of hemolymph lipids. This feature could limit endosymbiont over-proliferation under conditions of host nutrient limitation as lipid availability is strongly influenced by the nutritional state. PMID:25027439

  11. Applications of Mass Spectrometry to Lipids and Membranes

    PubMed Central

    Harkewicz, Richard; Dennis, Edward A.

    2012-01-01

    Lipidomics, a major part of metabolomics, constitutes the detailed analysis and global characterization, both spatial and temporal, of the structure and function of lipids (the lipidome) within a living system. As with proteomics, mass spectrometry has earned a central analytical role in lipidomics, and this role will continue to grow with technological developments. Currently, there exist two mass spectrometry-based lipidomics approaches, one based on a division of lipids into categories and classes prior to analysis, the “comprehensive lipidomics analysis by separation simplification” (CLASS), and the other in which all lipid species are analyzed together without prior separation, shotgun. In exploring the lipidome of various living systems, novel lipids are being discovered, and mass spectrometry is helping characterize their chemical structure. Deuterium exchange mass spectrometry (DXMS) is being used to investigate the association of lipids and membranes with proteins and enzymes, and imaging mass spectrometry (IMS) is being applied to the in situ analysis of lipids in tissues. PMID:21469951

  12. Electrostatically driven lipid-protein interaction: Answers from FRET.

    PubMed

    Fernandes, Fábio; Coutinho, Ana; Prieto, Manuel; Loura, Luís M S

    2015-09-01

    Electrostatics govern the association of a large number of proteins with cellular membranes. In some cases, these proteins present specialized lipid-binding modules or membrane targeting domains while in other cases association is achieved through nonspecific interaction of unstructured clusters of basic residues with negatively charged lipids. Given its spatial resolution in the nanometer range, Förster resonance energy transfer (FRET) is a powerful tool to give insight into protein-lipid interactions and provide molecular level information which is difficult to retrieve with other spectroscopic techniques. In this review we present and discuss the basic formalisms of both hetero- and homo-FRET pertinent to the most commonly encountered problems in lipid-protein interaction studies and highlight some examples of implementations of different FRET methodologies to characterize lipid/protein systems in which electrostatic interactions play a crucial role. This article is part of a Special Issue entitled: Lipid-protein interactions. PMID:25769805

  13. Enhanced lipid production in Chlorella pyrenoidosa by continuous culture.

    PubMed

    Wen, Xiaobin; Geng, Yahong; Li, Yeguang

    2014-06-01

    Usually microalgae growth and lipid accumulation do not run in parallel throughout cultivation, which necessarily lowers overall lipid productivity. However, we show through batch and feed-batch studies of Chlorella pyrenoidosa XQ-20044 that by varying the nitrate concentration, conditions which produce fairly high lipid content could be achieved without sacrificing algal growth. Simultaneous microalgae growth and lipid production was achieved in continuous chemostat culture when the specific nitrate input rate was in the range of 0.78-4.56mmolg(-1)d(-1). Moreover, the maximum lipid productivity (144.93mgL(-1)d(-1)) in the continuous culture was significantly higher than in batch culture (96.28mgL(-1)d(-1)), thus indicating the feasibility and great advantage of one-step production of microalgal lipids. PMID:24717322

  14. Lipid accumulation, lipid oxidation, and low plasma levels of acquired antibodies against oxidized lipids associate with degeneration and rupture of the intracranial aneurysm wall

    PubMed Central

    2013-01-01

    Background Rupture of a saccular intracranial aneurysm (sIA) causes an often fatal subarachnoid hemorrhage (SAH). Why some sIAs rupture remains unknown. Since sIA walls bear some histological similarities with early atherosclerotic lesions, we hypothesized that accumulation and oxidation of lipids might occur in the sIA wall and might associate with sIA wall degeneration. Tissue samples from sIA fundi (n = 54) were studied with histochemistry and a panel of previously characterized antibodies for epitopes of oxidized LDL (OxLDL). Plasma samples from sIA carriers (n = 125) were studied with ELISA and EIA for IgG and IgM -antibodies against a panel of OxLDL epitopes. Results Lipid accumulation, foam cells, and oxidized lipids were found both in unruptured and ruptured sIA walls. Lipid accumulation associated with wall degeneration (P < 0.001), as did the expression of adipophilin, a marker of lipid ingestion by cells. Lipid accumulation associated also with loss of mural cells (P < 0.001), as did the accumulation of OxLDL (P < 0.001). Plasma IgG antibody titers against OxLDL or malondialdehyde modified LDL were higher in patients with unruptured sIAs than in patients with aneurysmal SAH (P ? 0.001). A trend but not statistically significant differences were found in plasma IgM antibodies against oxidized lipids. Conclusions Accumulation of lipids and their oxidation in the sIA wall associates with the degeneration of the sIA wall. Acquired immunity against oxidized lipid epitopes may be protective of lipid associated sIA wall degeneration, but warrants further studies. PMID:24252658

  15. Bicarbonate trigger for inducing lipid accumulation in algal systems

    DOEpatents

    Gardner, Robert; Peyton, Brent; Cooksey, Keith E.

    2015-08-04

    The present invention provides bicarbonate containing and/or bicarbonate-producing compositions and methods to induce lipid accumulation in an algae growth system, wherein the algae growth system is under light-dark cycling condition. By adding said compositions at a specific growth stage, said methods lead to much higher lipid accumulation and/or significantly reduced total time required for accumulating lipid in the algae growth system.

  16. A multifunctional enzyme is involved in bacterial ether lipid biosynthesis.

    PubMed

    Lorenzen, Wolfram; Ahrendt, Tilman; Bozhüyük, Kenan A J; Bode, Helge B

    2014-06-01

    Fatty acid-derived ether lipids are present not only in most vertebrates but also in some bacteria. Here we describe what is to our knowledge the first gene cluster involved in the biosynthesis of such lipids in myxobacteria that encodes the multifunctional enzyme ElbD, which shows similarity to polyketide synthases. Initial characterization of elbD mutants in Myxococcus xanthus and Stigmatella aurantiaca showed the importance of these ether lipids for fruiting body formation and sporulation. PMID:24814673

  17. Correlations between anthropometry and lipid profile in type 2 diabetics

    PubMed Central

    Himabindu, Yalamanchali; Sriharibabu, Manne; Alekhya, Katamreddy; Saisumanth, Kandula; Lakshmanrao, Nambaru; Komali, Kanagala

    2013-01-01

    Over a period of time, anthropometric parameters have evolved into reliable indicators for predicting the incidence of diabetes mellitus. A number of studies have shown correlations between anthropometry and lipid profiles in healthy volunteers. This study examined correlations between anthropometry and lipid profile in type 2 diabetics. The limited observations made in this study reveal that anthropometric parameters are not ideal for predicting lipid profile abnormalities in type 2 diabetics. PMID:23961494

  18. Methods to create thermally oxidized lipids and comparison of analytical procedures to characterize peroxidation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this experiment was to evaluate peroxidation in 4 lipids, each with 3 degrees of peroxidation. Lipid sources were: corn oil (CN), canola oil (CA), poultry fat, and tallow. Peroxidation levels were: original lipids (OL), slow-oxidized lipids (SO), and rapid-oxidized lipids (RO). To p...

  19. Microalgal lipid droplets: composition, diversity, biogenesis and functions.

    PubMed

    Goold, Hugh; Beisson, Fred; Peltier, Gilles; Li-Beisson, Yonghua

    2015-04-01

    Lipid droplet is the major site of neutral lipid storage in eukaryotic cells, and increasing evidence show its involvement in numerous cellular processes such as lipid homeostasis, signaling, trafficking and inter-organelle communications. Although the biogenesis, structure, and functions of lipid droplets have been well documented for seeds of vascular plants, mammalian adipose tissues, insects and yeasts, relative little is known about lipid droplets in microalgae. Over the past 5 years, the growing interest of microalgae as a platform for biofuel, green chemicals or value-added polyunsaturated fatty acid production has brought algal lipid droplets into spotlight. Studies conducted on the green microalga Chlamydomonas reinhardtii and other model microalgae such as Haematococcus and Nannochloropsis species have led to the identification of proteins associated with lipid droplets, which include putative structural proteins different from plant oleosins and animal perilipins, as well as candidate proteins for lipid biosynthesis, mobilization, trafficking and homeostasis. Biochemical and microscopy studies have also started to shed light on the role of chloroplasts in the biogenesis of lipid droplets in Chlamydomonas. PMID:25433857

  20. Kdo2-lipid A: structural diversity and impact on immunopharmacology

    PubMed Central

    Wang, Xiaoyuan; Quinn, Peter J; Yan, Aixin

    2015-01-01

    3-deoxy-d-manno-octulosonic acid-lipid A (Kdo2-lipid A) is the essential component of lipopolysaccharide in most Gram-negative bacteria and the minimal structural component to sustain bacterial viability. It serves as the active component of lipopolysaccharide to stimulate potent host immune responses through the complex of Toll-like-receptor 4 (TLR4) and myeloid differentiation protein 2. The entire biosynthetic pathway of Escherichia coli Kdo2-lipid A has been elucidated and the nine enzymes of the pathway are shared by most Gram-negative bacteria, indicating conserved Kdo2-lipid A structure across different species. Yet many bacteria can modify the structure of their Kdo2-lipid A which serves as a strategy to modulate bacterial virulence and adapt to different growth environments as well as to avoid recognition by the mammalian innate immune systems. Key enzymes and receptors involved in Kdo2-lipid A biosynthesis, structural modification and its interaction with the TLR4 pathway represent a clear opportunity for immunopharmacological exploitation. These include the development of novel antibiotics targeting key biosynthetic enzymes and utilization of structurally modified Kdo2-lipid A or correspondingly engineered live bacteria as vaccines and adjuvants. Kdo2-lipid A/TLR4 antagonists can also be applied in anti-inflammatory interventions. This review summarizes recent knowledge on both the fundamental processes of Kdo2-lipid A biosynthesis, structural modification and immune stimulation, and applied research on pharmacological exploitations of these processes for therapeutic development. PMID:24838025

  1. Depth resolved detection of lipid using spectroscopic optical coherence tomography

    PubMed Central

    Fleming, Christine P.; Eckert, Jocelyn; Halpern, Elkan F.; Gardecki, Joseph A.; Tearney, Guillermo J.

    2013-01-01

    Optical frequency domain imaging (OFDI) can identify key components related to plaque vulnerability but can suffer from artifacts that could prevent accurate identification of lipid rich regions. In this paper, we present a model of depth resolved spectral analysis of OFDI data for improved detection of lipid. A quadratic Discriminant analysis model was developed based on phantom compositions known chemical mixtures and applied to a tissue phantom of a lipid-rich plaque. We demonstrate that a combined spectral and attenuation model can be used to predict the presence of lipid in OFDI images. PMID:24009991

  2. Counterion-mediated pattern formation in membranes containing anionic lipids

    PubMed Central

    Slochower, David R.; Wang, Yu-Hsiu; Tourdot, Richard W.; Radhakrishnan, Ravi; Janmey, Paul A.

    2014-01-01

    Most lipid components of cell membranes are either neutral, like cholesterol, or zwitterionic, like phosphatidylcholine and sphingomyelin. Very few lipids, such as sphingosine, are cationic at physiological pH. These generally interact only transiently with the lipid bilayer, and their synthetic analogs are often designed to destabilize the membrane for drug or DNA delivery. However, anionic lipids are common in both eukaryotic and prokaryotic cell membranes. The net charge per anionic phospholipid ranges from ?1 for the most abundant anionic lipids such has phosphatidylserine, to near ?7 for phosphatidylinositol 3,4,5 trisphosphate, although the effective charge depends on many environmental factors. Anionic phospholipids and other negatively charged lipids such as lipopolysaccharides are not randomly distributed in the lipid bilayer, but are highly restricted to specific leaflets of the bilayer and to regions near transmembrane proteins or other organized structures within the plane of the membrane. This review highlights some recent evidence that counterions, in the form of monovalent or divalent metal ions, polyamines, or cationic protein domains, have a large influence of the lateral distribution of anionic lipids within the membrane, and that lateral demixing of anionic lipids has effects on membrane curvature and protein function that are important for biological control. PMID:24556233

  3. Characterization of Titratable Amphiphiles in Lipid Membranes by Fluorescence Spectroscopy.

    PubMed

    Pierrat, Philippe; Lebeau, Luc

    2015-11-17

    Understanding the ionization behavior of lipid membranes is a key parameter for successful development of lipid-based drug delivery systems. Accurate determination of the ionization state of a titratable species incorporated in a lipid bilayer however requires special care. Herein we investigated the behavior of titratable lipids in liposomes by fluorescence spectroscopy and determined which extrinsic parameters-i.e., besides those directly related to their molecular structure-determine their ionization state. Two fluorescent dyes, TNS and R18, have been used to investigate basic and acidic titratable lipids, respectively. Our results suggest that the titration behavior of the ionizable lipid in the membrane is more sensitive to the composition of the membrane and to its physical state than to the presence of solutes in the aqueous phase. Essentially overlooked in earlier studies on ionizable lipid assemblies, the concentration of the titratable lipid in the membrane was found to have a major effect on the ionization state of the lipid polar head. This may result in a shift in the apparent pKa value which may be as large as two pKa units and cannot be satisfactorily predicted. PMID:26507074

  4. Functional One-Dimensional Lipid Bilayers on Carbon Nanotube Templates

    SciTech Connect

    Artyukhin, A; Shestakov, A; Harper, J; Bakajin, O; Stroeve, P; Noy, A

    2004-07-23

    We present one-dimensional (1-D) lipid bilayer structures that integrate carbon nanotubes with a key biological environment-phospholipid membrane. Our structures consist of lipid bilayers wrapped around carbon nanotubes modified with a hydrophilic polymer cushion layer. Despite high bilayer curvature, the lipid membrane maintains its fluidity and can sustain repeated damage-recovery cycles. We also present the first evidence of spontaneous insertion of pore-forming proteins into 1-D lipid bilayers. These structures could lead to the development of new classes of biosensors and bioelectronic devices.

  5. Coupled diffusion in lipid bilayers upon close approach.

    PubMed

    Pronk, Sander; Lindahl, Erik; Kasson, Peter M

    2015-01-21

    Biomembrane interfaces create regions of slowed water dynamics in their vicinity. When two lipid bilayers come together, this effect is further accentuated, and the associated slowdown can affect the dynamics of larger-scale processes such as membrane fusion. We have used molecular dynamics simulations to examine how lipid and water dynamics are affected as two lipid bilayers approach each other. These two interacting fluid systems, lipid and water, both slow and become coupled when the lipid membranes are separated by a thin water layer. We show in particular that the water dynamics become glassy, and diffusion of lipids in the apposed leaflets becomes coupled across the water layer, while the "outer" leaflets remain unaffected. This dynamic coupling between bilayers appears mediated by lipid-water-lipid hydrogen bonding, as it occurs at bilayer separations where water-lipid hydrogen bonds become more common than water-water hydrogen bonds. We further show that such coupling occurs in simulations of vesicle-vesicle fusion prior to the fusion event itself. Such altered dynamics at membrane-membrane interfaces may both stabilize the interfacial contact and slow fusion stalk formation within the interface region. PMID:25535654

  6. Lipid trafficking at endoplasmic reticulum-chloroplast membrane contact sites.

    PubMed

    Block, Maryse A; Jouhet, Juliette

    2015-08-01

    Glycerolipid synthesis in plant cells is characterized by an intense trafficking of lipids between the endoplasmic reticulum (ER) and chloroplasts. Initially, fatty acids are synthesized within chloroplasts and are exported to the ER where they are used to build up phospholipids and triacylglycerol. Ultimately, derivatives of these phospholipids return to chloroplasts to form galactolipids, monogalactosyldiacylglycerol and digalactosyldiacylglycerol, the main and essential lipids of photosynthetic membranes. Lipid trafficking was proposed to transit through membrane contact sites (MCSs) connecting both organelles. Here, we review recent insights into ER-chloroplast MCSs and lipid trafficking between chloroplasts and the ER. PMID:25868077

  7. Brain membrane lipids in major depression and anxiety disorders.

    PubMed

    Müller, Christian P; Reichel, Martin; Mühle, Christiane; Rhein, Cosima; Gulbins, Erich; Kornhuber, Johannes

    2015-08-01

    Major depression and anxiety disorders have high prevalence rates and are frequently comorbid. The neurobiological bases for these disorders are not fully understood, and available treatments are not always effective. Current models assume that dysfunctions in neuronal proteins and peptide activities are the primary causes of these disorders. Brain lipids determine the localization and function of proteins in the cell membrane and in doing so regulate synaptic throughput in neurons. Lipids may also leave the membrane as transmitters and relay signals from the membrane to intracellular compartments or to other cells. Here we review how membrane lipids, which play roles in the membrane's function as a barrier and a signaling medium for classical transmitter signaling, contribute to depression and anxiety disorders and how this role may provide targets for lipid-based treatment approaches. Preclinical findings have suggested a crucial role for the membrane-forming n-3 polyunsaturated fatty acids, glycerolipids, glycerophospholipids, and sphingolipids in the induction of depression- and anxiety-related behaviors. These polyunsaturated fatty acids also offer new treatment options such as targeted dietary supplementation or pharmacological interference with lipid-regulating enzymes. While clinical trials support this view, effective lipid-based therapies may need more individualized approaches. Altogether, accumulating evidence suggests a crucial role for membrane lipids in the pathogenesis of depression and anxiety disorders; these lipids could be exploited for improved prevention and treatment. This article is part of a Special Issue entitled Brain Lipids. PMID:25542508

  8. 21 CFR 862.1470 - Lipid (total) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1470 Lipid (total) test system. (a)...

  9. ARFGAP1 Is Dynamically Associated with Lipid Droplets in Hepatocytes

    PubMed Central

    Alamri, Hussam; Feng, Shi Bo; Kalantari, Fariba; Negi, Sarita; Wong, Amy H. Y.; Mazur, Alexander; Asp, Lennart; Fazel, Ali; Salman, Ayat; Lazaris, Anthoula; Metrakos, Peter; Bergeron, John J. M.; Nilsson, Tommy

    2014-01-01

    The ARF GTPase Activating Protein 1 (ARFGAP1) associates mainly with the cytosolic side of Golgi cisternal membranes where it participates in the formation of both COPI and clathrin-coated vesicles. In this study, we show that ARFGAP1 associates transiently with lipid droplets upon addition of oleate in cultured cells. Also, that addition of cyclic AMP shifts ARFGAP1 from lipid droplets to the Golgi apparatus and that overexpression and knockdown of ARFGAP1 affect lipid droplet formation. Examination of human liver tissue reveals that ARFGAP1 is found associated with lipid droplets at steady state in some but not all hepatocytes. PMID:25397679

  10. Isolation and characterization of lipid in phloem sap of canola.

    PubMed

    Madey, Ewa; Nowack, Linda M; Thompson, John E

    2002-02-01

    Phloem isolated from canola (Brassica napus L.) stems was found to contain phospholipid, diacylglycerol, triacylglycerol, steryl and wax esters, and comparatively high concentrations of unesterified fatty acids. Indeed, the composition of phloem lipid was markedly different from that of microsomal membranes and cytosol isolated from both leaves and stems. Specifically, phloem lipid consisted predominantly of unesterified fatty acids and was enriched in medium-chain fatty acids, in particular, lauric, myristic and pentadecanoic acids. This unique composition also distinguished phloem lipid from that of well-characterized cytosolic lipid particles such as oil bodies found in plant cells. Moreover, levels of medium-chain fatty acids in the phloem increased when canola plants were stressed by exposure to sublethal doses of ultraviolet irradiation. Phloem levels of lauric acid, for example, increased by 11-fold upon treatment with sublethal ultraviolet irradiation. Spherical lipid particles were discernible in isolated phloem sap by electron microscopy, suggesting that the lipid in phloem is in the form of lipid particles. The presence of lipid in phloem may be reflective of long-distance lipid transport in plants, primarily in the form of free fatty acids. PMID:11925046

  11. Fluid and Resistive Tethered Lipid Membranes on Nanoporous Substrates.

    PubMed

    Gupta, Gautam; Staggs, Kyle; Mohite, Aditya D; Baldwin, Jon K; Iyer, Srinivas; Mukundan, Rangachary; Misra, Amit; Antoniou, Antonia; Dattelbaum, Andrew M

    2015-10-01

    Cell membranes perform important biological roles including compartmentalization, signaling, and transport of nutrients. Supported lipid membranes mimic the behavior of cell membranes and are an important model tool for studying membrane properties in a controlled laboratory environment. Lipid membranes may be supported on solid substrates; however, protein and lipid interactions with the substrate typically result in their denaturation. In this report, we demonstrate the formation of intact lipid membranes tethered on nanoporous metal thin films obtained via a dealloying process. Uniform lipid membranes were formed when the surface defect density of the nanoporous metal film was significantly reduced through a two-step dealloying process reported here. We show that the tethered lipid membranes on nanoporous metal substrates maintain both fluidity and electrical resistivity, which are key attributes to naturally occurring lipid membranes. The lipid assemblies supported on nanoporous metals provide a new platform for investigating lipid membrane properties, and potentially membrane proteins, for numerous applications including next generation biosensor platforms, targeted drug-delivery, and energy harvesting devices. PMID:26390189

  12. Thermal stability of ladderane lipids as determined by hydrous pyrolysis

    USGS Publications Warehouse

    Jaeschke, A.; Lewan, M.D.; Hopmans, E.C.; Schouten, S.; Sinninghe, Damste J.S.

    2008-01-01

    Anaerobic ammonium oxidation (anammox) has been recognized as a major process resulting in loss of fixed inorganic nitrogen in the marine environment. Ladderane lipids, membrane lipids unique to anammox bacteria, have been used as markers for the detection of anammox in marine settings. However, the fate of ladderane lipids after sediment burial and maturation is unknown. In this study, anammox bacterial cell material was artificially matured by hydrous pyrolysis at constant temperatures ranging from 120 to 365 ??C for 72 h to study the stability of ladderane lipids during progressive dia- and catagenesis. HPLC-MS/MS analysis revealed that structural alterations of ladderane lipids already occurred at 120 ??C. At temperatures >140 ??C, ladderane lipids were absent and only more thermally stable products could be detected, i.e., ladderane derivatives in which some of the cyclobutane rings were opened. These diagenetic products of ladderane lipids were still detectable up to temperatures of 260 ??C using GC-MS. Thus, ladderane lipids are unlikely to occur in ancient sediments and sedimentary rocks, but specific diagenetic products of ladderane lipids will likely be present in sediments and sedimentary rocks of relatively low maturity (i.e., C31 hopane 22S/(22S + 22R) ratio 0.5). ?? 2008 Elsevier Ltd.

  13. Electric polarizability of lipid bilayers: The influence of the structure

    NASA Astrophysics Data System (ADS)

    Soussi, J.; Chalopin, Y.

    2015-10-01

    We have calculated the electric polarizability of two types of lipid bilayers, formed by 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1-palmitoyl-2- oleoyl-sn-glycero-3-phosphocholine (POPC) lipids. We demonstrate that despite the very similar chemical structures, the bilayers exhibit dramatically different terahertz infrared (IR) properties. We demonstrate that the chemical structure of the lipids influences the morphology of the bilayers, which in turn impacts their IR responses: interestingly, both structures exhibit a non-uniform absorption. For the case of DPPC, the infrared absorption is mostly driven by the hydrophilic heads, whereas for the POPC lipids, the absorption occurs predominately at the hydrophobic tails.

  14. Polymer-induced tubulation in lipid vesicles

    E-print Network

    F. Campelo; A. Hernandez-Machado

    2008-04-21

    A mechanism of extraction of tubular membranes from a lipid vesicle is presented. A concentration gradient of anchoring amphiphilic polymers generates tubes from bud-like vesicle protrusions. We explain this mechanism in the framework of the Canham-Helfrich model. The energy profile is analytically calculated and a tube with a fixed length, corresponding to an energy minimum, is obtained in a certain regime of parameters. Further, using a phase-field model, we corroborate these results numerically. We obtain the growth of tubes when a polymer source is added, and the bud-like shape after removal of the polymer source, in accordance with recent experimental results.

  15. Lipid profiles of judo athletes during Ramadan.

    PubMed

    Chaouachi, A; Chamari, K; Roky, R; Wong, P; Mbazaa, A; Bartagi, Z; Amri, M

    2008-04-01

    The effect of Ramadan intermittent fasting (RIF) was studied on a battery of blood lipid markers in 15 elite judo athletes during a period when they were maintaining their training load without competing. Nine-to-twelve hours postprandial serum lipid and lipoproteins were measured on five occasions: before, three times during Ramadan, and three weeks post-Ramadan. Dietary data were collected using a 24-hour recall method for three days before, during and after the Ramadan month. Mean energy intake (12.9 MJ/d) remained similar throughout the study as did the macronutrient constituents of the diet. Mean body mass was slightly reduced (2 %; p < 0.01) by the end of Ramadan due mainly to a 0.65 +/- 0.68 kg decrease in body fat (p < 0.05). The RIF produced significant changes in some of the blood lipid levels: both HDL-C and LDL-C increased by 0.12 (p < 0.01) and 0.20 mmol . l (-1) (p < 0.05), respectively. During Ramadan, mean non-esterified fatty acid (NEFA) levels decreased from 0.73 to 0.28 mmol . l (-1) (p < 0.01) during the first week, then increased (p < 0.05) to 1.22 mmol . l (-1) over the middle of Ramadan and recovered to pre-Ramadan concentrations for the end and the post-Ramadan periods. Apolipoprotein A1 (Apo-A1) levels were significantly elevated at the end (p < 0.01) and the post-Ramadan periods (p < 0.05). Three weeks after Ramadan, blood levels of glucose, NEFA, Apo-A1, and Apo-B did not return to the values observed before Ramadan. In conclusion, the present results show that the combination of the change in diet pattern during Ramadan, along with intense exercise training, induced a significant decrease in body mass associated with a reduction in body fat and changes in some of the serum lipids and lipoproteins. Nevertheless, all the measured serum parameters remained within normal levels for young and active individuals. The volunteers, in this study, were able to maintain a constant training load during RIF. PMID:17879887

  16. Self-assembled lipid bilayer materials

    DOEpatents

    Sasaki, Darryl Y.; Waggoner, Tina A.; Last, Julie A.

    2005-11-08

    The present invention is a self-assembling material comprised of stacks of lipid bilayers formed in a columnar structure, where the assembly process is mediated and regulated by chemical recognition events. The material, through the chemical recognition interactions, has a self-regulating system that corrects the radial size of the assembly creating a uniform diameter throughout most of the structure. The materials form and are stable in aqueous solution. These materials are useful as structural elements for the architecture of materials and components in nanotechnology, efficient light harvesting systems for optical sensing, chemical processing centers, and drug delivery vehicles.

  17. THE ROLE OF LIPID BILAYER MECHANICS IN MECHANOSENSATION The Role of Lipid Bilayer Mechanics in Mechanosensation

    E-print Network

    Phillips, Rob

    of mechanosensation is rapidly advancing as a result of both structural and functional studies. One intriguing mode is to catalogue recent work that uses a mix of continuum and statistical mechanics to explore the role experimental techniques. Keywords: lipid bilayer mechanics | statistical mechanics | mechanosensitive ion

  18. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) for application of ascorbyl palmitate.

    PubMed

    Uner, M; Wissing, S A; Yener, G; Müller, R H

    2005-08-01

    The aim of this study was to improve the chemical stability of ascorbyl palmitate (AP) in a colloidal lipid carrier for its topical use. For this purpose, AP-loaded solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC) and for comparison, a nanoemulsion (NE) were prepared employing the high pressure homogenization technique and stored at room temperature (RT), 4 degrees C and 40 degrees C. During 3 months, physical stability of these formulations compared to placebo formulations which were prepared by the same production method, was studied including recrystallization behaviour of the lipid with differential scanning calorimetry (DSC), particle size distribution and storage stability with photon correlation spectroscopy (PCS) and laser diffractometry (LD). After evaluating data indicating excellent physical stability, AP-loaded SLN, NLC and NE were incorporated into a hydrogel by the same production method as the next step. Degradation of AP by HPLC and physical stability in the same manner were investigated at the same storage temperatures during 3 months. As a result, AP was found most stable in both the NLC and SLN stored at 4 degrees C (p > 0.05) indicating the importance of storage temperature. Nondegraded AP content in NLC, SLN and NE was found to be 71.1% +/- 1.4, 67.6% +/- 2.9 and 55.2% +/- 0.3 after 3 months, respectively. Highest degradation was observed with NE at all the storage temperatures indicating even importance of the carrier structure. PMID:16124399

  19. Effect of Extrusion Pressure and Lipid Properties on the Size and Polydispersity of Lipid Vesicles

    E-print Network

    in research laborato- ries as model membranes and in the pharmaceutical industry as drug delivery agents, is an important aspect of their recent application to drug delivery technologies. One popular production method with the lysis tension of the lipid bilayer rather than any bending modulus of the system. The flow rate of equal

  20. Physicochemical properties of nevirapine-loaded solid lipid nanoparticles and nanostructured lipid carriers.

    PubMed

    Kuo, Yung-Chih; Chung, Jui-Fang

    2011-04-01

    Solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) coated with human serum albumin (HSA) were fabricated for formulating nevirapine (NVP). Here, NLCs contained low-melting-point oleic acid (OA) in the internal lipid phase. The results revealed that the two nanoparticles were uniformly distributed with the average diameter ranging from 145 to 180 nm. The surface HSA neutralized the positive charge of dimethyldioctadecyl ammonium bromide (DODAB) on SLNs and NLCs and reduced their zeta potential. In a fixed ratio of solid lipids, SLNs entrapped more NVP than NLCs. The incorporation of OA also reduced the thermal resistance of NLCs and accelerated the release of NVP from the nanocarriers. When incubated with DODAB-stabilized SLNs, the viability of human brain-microvascular endothelial cells (HBMECs) reduced. However, the surface HSA increased the viability of HBMECs about 10% when the concentration of SLNs was higher than 0.8 mg/mL. HSA-grafted SLNs and NLCs can be effective formulations in the delivery of NVP for viral therapy. PMID:21194902

  1. Micrometric segregation of fluorescent membrane lipids: relevance for endogenous lipids and biogenesis in erythrocytes.

    PubMed

    D'Auria, Ludovic; Fenaux, Marisa; Aleksandrowicz, Paulina; Van Der Smissen, Patrick; Chantrain, Christophe; Vermylen, Christiane; Vikkula, Miikka; Courtoy, Pierre J; Tyteca, Donatienne

    2013-04-01

    Micrometric membrane lipid segregation is controversial. We addressed this issue in attached erythrocytes and found that fluorescent boron dipyrromethene (BODIPY) analogs of glycosphingolipids (GSLs) [glucosylceramide (BODIPY-GlcCer) and monosialotetrahexosylganglioside (GM1BODIPY)], sphingomyelin (BODIPY-SM), and phosphatidylcholine (BODIPY-PC inserted into the plasma membrane spontaneously gathered into distinct submicrometric domains. GM1BODIPY domains colocalized with endogenous GM1 labeled by cholera toxin. All BODIPY-lipid domains disappeared upon erythrocyte stretching, indicating control by membrane tension. Minor cholesterol depletion suppressed BODIPY-SM and BODIPY-PC but preserved BODIPY-GlcCer domains. Each type of domain exchanged constituents but assumed fixed positions, suggesting self-clustering and anchorage to spectrin. Domains showed differential association with 4.1R versus ankyrin complexes upon antibody patching. BODIPY-lipid domains also responded differentially to uncoupling at 4.1R complexes [protein kinase C (PKC) activation] and ankyrin complexes (in spherocytosis, a membrane fragility disease). These data point to micrometric compartmentation of polar BODIPY-lipids modulated by membrane tension, cholesterol, and differential association to the two nonredundant membrane:spectrin anchorage complexes. Micrometric compartmentation might play a role in erythrocyte membrane deformability and fragility. PMID:23322884

  2. Lipid Lowering Effect of Punica granatum L. Peel in High Lipid Diet Fed Male Rats

    PubMed Central

    Sadeghipour, Alireza; Ilchizadeh Kavgani, Ali; Ghahramani, Reza; Shahabzadeh, Saleh; Anissian, Ali

    2014-01-01

    Many herbal medicines have been recommended for the treatment of dyslipidemia. The antilipidemic effect of hydroethanolic extract of pomegranate peel (Punica granatum L.) was investigated in high lipid diet fed male rats. Intraperitoneally administration of pomegranate peel extract (50, 100, 200, and 300?mg/kg body weight) for 23 days on the levels of serum cholesterol, triglycerides, LDL, HDL, alkaline phosphatase (AP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) in high lipid diet fed male rats was evaluated. Treatment of pomegranate extract decreased body weight in treated rats, significantly. Administration of the plant extract significantly decreased serum total cholesterol, triglycerides, LDL-C, alkaline phosphatise, AST, and ALT levels, whereas it increased serum HDL-C in high lipid diet fed rats in comparison to saline control group. Also, histopathological study showed that treatment of pomegranate peel extract attenuates liver damage in high lipid diet fed rats in comparison to saline group. It is concluded that the plant should be considered as an excellent candidate for future studies on dyslipidemia. PMID:25295067

  3. Oral mucosal lipids are antibacterial against Porphyromonas gingivalis, induce ultrastructural damage, and alter bacterial lipid and protein compositions

    PubMed Central

    Fischer, Carol L; Walters, Katherine S; Drake, David R; Dawson, Deborah V; Blanchette, Derek R; Brogden, Kim A; Wertz, Philip W

    2013-01-01

    Oral mucosal and salivary lipids exhibit potent antimicrobial activity for a variety of Gram-positive and Gram-negative bacteria; however, little is known about their spectrum of antimicrobial activity or mechanisms of action against oral bacteria. In this study, we examine the activity of two fatty acids and three sphingoid bases against Porphyromonas gingivalis, an important colonizer of the oral cavity implicated in periodontitis. Minimal inhibitory concentrations, minimal bactericidal concentrations, and kill kinetics revealed variable, but potent, activity of oral mucosal and salivary lipids against P. gingivalis, indicating that lipid structure may be an important determinant in lipid mechanisms of activity against bacteria, although specific components of bacterial membranes are also likely important. Electron micrographs showed ultrastructural damage induced by sapienic acid and phytosphingosine and confirmed disruption of the bacterial plasma membrane. This information, coupled with the association of treatment lipids with P. gingivalis lipids revealed via thin layer chromatography, suggests that the plasma membrane is a likely target of lipid antibacterial activity. Utilizing a combination of two-dimensional in-gel electrophoresis and Western blot followed by mass spectroscopy and N-terminus degradation sequencing we also show that treatment with sapienic acid induces upregulation of a set of proteins comprising a unique P. gingivalis stress response, including proteins important in fatty acid biosynthesis, metabolism and energy production, protein processing, cell adhesion and virulence. Prophylactic or therapeutic lipid treatments may be beneficial for intervention of infection by supplementing the natural immune function of endogenous lipids on mucosal surfaces. PMID:23867843

  4. Doubly-lipid-modified protein sequence motifs exhibit long-lived anchorage to lipid bilayer membranes.

    PubMed

    Shahinian, S; Silvius, J R

    1995-03-21

    To understand better the potential functional importance of the dual-lipid modifications found in a number of intracellular proteins of eukaryotes, we have examined how "tenaciously" various doubly-lipid-modified peptides, with sequences and lipid modifications reflecting those found in intracellular proteins, are anchored to lipid bilayer membranes. Fluorescent-labeled peptides bearing dual-lipid modifications were incorporated into large unilamellar egg phosphatidylcholine/phosphatidylglycerol vesicles, and the kinetics of spontaneous intervesicle transfer of the lipopeptides were monitored by a fluorescence-dequenching assay. Lipopeptides incorporating the stable "dual-anchor" motif -C(geranylgeranyl)XC(geranylgeranyl)-OMe found in several rab and homologous proteins exhibit very slow rates of interbilayer transfer (t1/2 > 50 h), as do lipopeptides incorporating myristoyl-GC(palmitoyl)X- and -C(palmitoyl)XC(farnesyl)-OMe motifs found in various src-related intracellular tyrosine kinases and G-protein alpha-subunits and in p21H-ras, respectively. Lipopeptides terminating in an unmethylated -C(geranylgeranyl)C(geranylgeranyl)-OH motif show somewhat greater but still very slow rates of spontaneous interbilayer transfer (t1/2 = ca. 10 h). Extrapolating from these results, we estimate that the rate of spontaneous desorption of the corresponding doubly-anchored proteins from membranes should be much slower than that of regulated, protein-mediated release (effected by binding to an "escort" protein or by de-S-acylation). As a result the intracellular distributions of these species (and particularly their targeting to specific intracellular membranes) are likely to be governed (and regulated) primarily by kinetic rather than thermodynamic factors.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7893678

  5. Mobile lipid bilayers on gold surfaces through structure-induced lipid vesicle rupture.

    PubMed

    Peng, Po-Yu; Chiang, Po-Chieh; Chao, Ling

    2015-04-01

    Forming fluid supported lipid bilayers (SLBs) on a gold surface can enable various lipid-membrane-associated biomolecular interactions to be investigated by several surface sensing techniques, such as surface plasmon resonance and scanning tunneling microscopy. However, forming fluid SLBs on a gold surface through lipid vesicle deposition continues to pose a challenge. In this study, we constructed nanograting structures on a gold surface to induce lipid vesicle rupture for forming a mobile layer of SLBs. Observations based on fluorescence recovery after photobleaching showed that SLBs on the prepared grating supports had some fluidity, while SLBs on the planar support had no fluidity. The anisotropic fluorescence intensity recovery shape changes observed in the SLBs on the grating support suggested that a second layer of SLBs partially formed on top of the first layer in contact with the gold surface and extended along the grating structure. Comparisons of the relative amounts of second bilayer and the fluorescence recovery fractions on supports with various grating edge densities suggested that the second layer formed at the edge regions and that the coverage ratio was directly proportional to the grating edge density. All of these results showed that the grating edges could serve as vesicle-rupture-inducing sites for the formation of a mobile second SLB on a gold surface. The formation of the second layer of SLBs at the edge regions but not in the flat regions enabled us to determine the second layer locations and provided us with an opportunity to pattern mobile lipid bilayers on gold surfaces by controlling the edge locations. PMID:25746237

  6. Segregation of Fluorescent Membrane Lipids into Distinct Micrometric Domains: Evidence for Phase Compartmentation of Natural Lipids?

    PubMed Central

    D?auria, Ludovic; Van Der Smissen, Patrick; Bruyneel, Frédéric

    2011-01-01

    Background We recently reported that sphingomyelin (SM) analogs substituted on the alkyl chain by various fluorophores (e.g. BODIPY) readily inserted at trace levels into the plasma membrane of living erythrocytes or CHO cells and spontaneously concentrated into micrometric domains. Despite sharing the same fluorescent ceramide backbone, BODIPY-SM domains segregated from similar domains labelled by BODIPY-D-e-lactosylceramide (D-e-LacCer) and depended on endogenous SM. Methodology/Principal Findings We show here that BODIPY-SM further differed from BODIPY-D-e-LacCer or -glucosylceramide (GlcCer) domains in temperature dependence, propensity to excimer formation, association with a glycosylphosphatidylinositol (GPI)-anchored fluorescent protein reporter, and lateral diffusion by FRAP, thus demonstrating different lipid phases and boundaries. Whereas BODIPY-D-e-LacCer behaved like BODIPY-GlcCer, its artificial stereoisomer, BODIPY-L-t-LacCer, behaved like BODIPY- and NBD-phosphatidylcholine (PC). Surprisingly, these two PC analogs also formed micrometric patches yet preferably at low temperature, did not show excimer, never associated with the GPI reporter and showed major restriction to lateral diffusion when photobleached in large fields. This functional comparison supported a three-phase micrometric compartmentation, of decreasing order: BODIPY-GSLs > -SM > -PC (or artificial L-t-LacCer). Co-existence of three segregated compartments was further supported by double labelling experiments and was confirmed by additive occupancy, up to ?70% cell surface coverage. Specific alterations of BODIPY-analogs domains by manipulation of corresponding endogenous sphingolipids suggested that distinct fluorescent lipid partition might reflect differential intrinsic propensity of endogenous membrane lipids to form large assemblies. Conclusions/Significance We conclude that fluorescent membrane lipids spontaneously concentrate into distinct micrometric assemblies. We hypothesize that these might reflect preexisting compartmentation of endogenous PM lipids into non-overlapping domains of differential order: GSLs > SM > PC, resulting into differential self-adhesion of the two former, with exclusion of the latter. PMID:21386970

  7. Factors influencing particulate lipid production in the East Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Gašparovi?, B.; Frka, S.; Koch, B. P.; Zhu, Z. Y.; Bracher, A.; Lechtenfeld, O. J.; Neogi, S. B.; Lara, R. J.; Kattner, G.

    2014-07-01

    Extensive analyses of particulate lipids and lipid classes were conducted to gain insight into lipid production and related factors along the biogeochemical provinces of the Eastern Atlantic Ocean. Data are supported by particulate organic carbon (POC), chlorophyll a (Chl a), phaeopigments, Chl a concentrations and carbon content of eukaryotic micro-, nano- and picophytoplankton, including cell abundances for the latter two and for cyanobacteria and prokaryotic heterotrophs. We focused on the productive ocean surface (2 m depth and deep Chl a maximum (DCM). Samples from the deep ocean provided information about the relative reactivity and preservation potential of particular lipid classes. Surface and DCM particulate lipid concentrations (3.5-29.4 ?g L-1) were higher than in samples from deep waters (3.2-9.3 ?g L-1) where an increased contribution to the POC pool was observed. The highest lipid concentrations were measured in high latitude temperate waters and in the North Atlantic Tropical Gyral Province (13-25°N). Factors responsible for the enhanced lipid synthesis in the eastern Atlantic appeared to be phytoplankton size (micro, nano, pico) and the low nutrient status with microphytoplankton having the most expressed influence in the surface and eukaryotic nano- and picophytoplankton in the DCM layer. Higher lipid to Chl a ratios suggest enhanced lipid biosynthesis in the nutrient poorer regions. The various lipid classes pointed to possible mechanisms of phytoplankton adaptation to the nutritional conditions. Thus, it is likely that adaptation comprises the replacement of membrane phospholipids by non-phosphorus containing glycolipids under low phosphorus conditions. The qualitative and quantitative lipid compositions revealed that phospholipids were the most degradable lipids, and their occurrence decreased with increasing depth. In contrast, wax esters, possibly originating from zooplankton, survived downward transport probably due to the fast sinking rate of particles (fecal pellets). The important contribution of glycolipids in deep waters reflected their relatively stable nature and degradation resistance. A lipid-based proxy for the lipid degradative state (Lipolysis Index) suggests that many lipid classes were quite resistant to degradation even in the deep ocean.

  8. Membranes: a meeting point for lipids, proteins and therapies

    PubMed Central

    Escribá, Pablo V; González-Ros, José M; Goñi, Félix M; Kinnunen, Paavo K J; Vigh, Lászlo; Sánchez-Magraner, Lissete; Fernández, Asia M; Busquets, Xavier; Horváth, Ibolya; Barceló-Coblijn, Gwendolyn

    2008-01-01

    Abstract Membranes constitute a meeting point for lipids and proteins. Not only do they define the entity of cells and cytosolic organelles but they also display a wide variety of important functions previously ascribed to the activity of proteins alone. Indeed, lipids have commonly been considered a mere support for the transient or permanent association of membrane proteins, while acting as a selective cell/organelle barrier. However, mounting evidence demonstrates that lipids themselves regulate the location and activity of many membrane proteins, as well as defining membrane microdomains that serve as spatio-temporal platforms for interacting signalling proteins. Membrane lipids are crucial in the fission and fusion of lipid bilayers and they also act as sensors to control environmental or physiological conditions. Lipids and lipid structures participate directly as messengers or regulators of signal transduction. Moreover, their alteration has been associated with the development of numerous diseases. Proteins can interact with membranes through lipid co-/post-translational modifications, and electrostatic and hydrophobic interactions, van der Waals forces and hydrogen bonding are all involved in the associations among membrane proteins and lipids. The present study reviews these interactions from the molecular and biomedical point of view, and the effects of their modulation on the physiological activity of cells, the aetiology of human diseases and the design of clinical drugs. In fact, the influence of lipids on protein function is reflected in the possibility to use these molecular species as targets for therapies against cancer, obesity, neurodegenerative disorders, cardiovascular pathologies and other diseases, using a new approach called membrane-lipid therapy. PMID:18266954

  9. Exploring the existence of lipid rafts in bacteria

    PubMed Central

    Bramkamp, Marc; Lopez, Daniel

    2015-01-01

    1. Summary An interesting concept in the organization of cellular membranes is the proposed existence of lipid rafts. Membranes of eukaryotic cells organize signal transduction proteins into membrane rafts or lipid rafts, that are enriched in particular lipids like cholesterol and are important for the correct functionality of diverse cellular processes. The assembly of lipid rafts in eukaryotes has been considered a fundamental step during the evolution of cellular complexity, suggesting that bacteria and archaea were too simple organisms to require such a sophisticated organization of their cellular membranes. However, it was recently discovered that bacteria organize many signal transduction, protein secretion and transport processes in functional membrane microdomains, which are equivalent to the lipid rafts of eukaryotic cells. This review contains the most significant advances during the last four years to understand the structural and biological role of lipid rafts in bacteria. Furthermore, this review shows a detailed description of a number of molecular and genetic approaches related to the discovery of bacterial lipid rafts as well as an overview of the group of tentative lipid-protein and protein-protein interactions that give consistency to these sophisticated signaling platforms. Additional data is presented in this review suggesting that lipid rafts are widely distributed in bacteria. Therefore, we discuss the available techniques and optimized protocols for the purification and analysis of rafts-associated proteins in various bacterial species to purposively the study of bacterial lipid rafts to other laboratories that could be interested in the topic. Overall, the discovery of lipid rafts in bacteria reveals a new level of sophistication in signal transduction and membrane organization that was unexpected in bacteria and shows that bacteria are more complex organisms than previously appreciated. PMID:25652542

  10. Methane-Derived Hydrogen in Lipids Produced by Aerobic Methanotrophs

    NASA Astrophysics Data System (ADS)

    Sessions, A. L.; Jahnke, L. L.; Schimmelmann, A.; Hayes, J. M.

    2001-12-01

    Combined hydrogen- and carbon-isotopic analyses of methane often provide important clues about its origin. Unfortunately, methane is not preserved in the geologic record so these analyses can only examine trapped or actively produced methane. The lipids of microorganisms that consume methane potentially record its isotopic composition, and are accessible throughout most of the geologic record. Those lipids therefore represent a potential means for examining the characteristics of methane released into the oceans over geologic history. We have examined the hydrogen-isotopic relationships between methane and lipids in the aerobic methanotroph Methylococcus capsulatus using cultures in which the D/H ratio of supplied water and methane were controlled independently. Resulting ? D values were measured for a range of fatty acids, sterols, and hopanols using isotope-ratio-monitoring gas chromatography/mass spectrometry. We estimate that 31 +/- 2% of hydrogen in every lipid we examined is derived from methane, regardless of whether cultures were harvested in exponential or stationary phase. The biochemical pathways responsible for the transfer of hydrogen from methane to lipids are not fully understood. Isotope fractionation associated with the utilization of methane (i.e., ? lipid/methane) averages 0.986 for fatty acids and 0.789 for isoprenoid lipids. For water, fractionation (? lipid/water) averages 0.938 for fatty acids and 0.831 for isoprenoid lipids. Given typical ? D values for seawater (0%) and thermogenic `dry' methane (-150‰ ), fatty acids from M. capsulatus should have ? D values near -95‰ , and isoprenoids should have ? D values near -215‰ . Using ? Dmethane = -300‰ , a value near the lower limit of those for biogenic methanes, we predict ? D values for methanotroph fatty acids and isoprenoid lipids of -140 and -260‰ , respectively. It appears possible that D/H measurements of lipids from methanotrophic bacteria will provide useful hydrogen-isotopic information about methane that has been entirely consumed.

  11. Lipid emulsions – Guidelines on Parenteral Nutrition, Chapter 6

    PubMed Central

    Adolph, M.; Heller, A. R.; Koch, T.; Koletzko, B.; Kreymann, K. G.; Krohn, K.; Pscheidl, E.; Senkal, M.

    2009-01-01

    The infusion of lipid emulsions allows a high energy supply, facilitates the prevention of high glucose infusion rates and is indispensable for the supply with essential fatty acids. The administration of lipid emulsions is recommended within ?7 days after starting PN (parenteral nutrition) to avoid deficiency of essential fatty acids. Low-fat PN with a high glucose intake increases the risk of hyperglycaemia. In parenterally fed patients with a tendency to hyperglycaemia, an increase in the lipid-glucose ratio should be considered. In critically ill patients the glucose infusion should not exceed 50% of energy intake. The use of lipid emulsions with a low phospholipid/triglyceride ratio is recommended and should be provided with the usual PN to prevent depletion of essential fatty acids, lower the risk of hyperglycaemia, and prevent hepatic steatosis. Biologically active vitamin E (?-tocopherol) should continuously be administered along with lipid emulsions to reduce lipid peroxidation. Parenteral lipids should provide about 25–40% of the parenteral non-protein energy supply. In certain situations (i.e. critically ill, respiratory insufficiency) a lipid intake of up to 50 or 60% of non-protein energy may be reasonable. The recommended daily dose for parenteral lipids in adults is 0.7–1.3 g triglycerides/kg body weight. Serum triglyceride concentrations should be monitored regularly with dosage reduction at levels >400 mg/dl (>4.6 mmol/l) and interruption of lipid infusion at levels >1000 mg/dl (>11.4 mmol/l). There is little evidence at this time that the choice of different available lipid emulsions affects clinical endpoints. PMID:20049078

  12. Alterations in cell lipid metabolism by glycol methacrylate (HEMA).

    PubMed

    Schuster, G S; Caughman, G B; Rueggeberg, F A; Lefebvre, C A; Cibirka, R

    1999-01-01

    Components of dental resins such as dimethylaminoethyl methacrylate (DMAEMA) can alter cell lipid composition, presumably by esterase-mediated hydrolysis. The resulting dimethylethanolamine is incorporated into cell phospholipids, while the methacrylic acid may alter several metabolic pathways. We hypothesize that HEMA is cleaved in a similar manner and the released ethylene glycol is incorporated into cell lipids, yielding phosphatidylethylene glycol (PtEG), and the methacrylic acid alters other lipid pathways in a manner similar to that of methacrylic acid released from hydrolysis of DMAEMA. Cultures of hamster buccal pouch (HCP) and rabbit kidney (RK13) epithelial cells were exposed to subtoxic concentrations of HEMA in the presence of [14C]-acetate or [3H]-oleic acid. Other cultures were prelabeled with [14C]-acetate followed by exposure to various concentrations of HEMA. Cell lipids were extracted by the method of Bligh and Dyer and separated by thin layer chromatography on silica gel K-6 plates or SG-81 silica gel loaded chromatography paper. The fate of the ethylene glycol was traced using [14C]-ethylene glycol. Radioactive lipids were located using autoradiography and known standard lipids and quantitated by liquid scintillation spectrometry. In the presence of HEMA several classes of lipids were altered. Among the neutral lipids, the most notable changes involved sterol precursors, triglycerides, fatty acids, and cholesterol esters, while phosphatidylcholine was affected among the phospholipids. The results differed quantitatively between the two cell types. Results also suggest that EG, including that released by hydrolysis of HEMA, is incorporated into cell phospholipids, producing PtEG. The changes in neutral lipid labeling may occur by alteration of lipid synthetic pathways utilizing acetyl Co-A as well as inhibition of enzymes involved in synthesis of cholesterol from sterol precursors and hydrolysis of cholesterol esters. Synthesis of PtEG may take place via phospholipase D-mediated headgroup exchange. Alterations in the cellular lipids may affect cell membrane properties and associated cell functions. PMID:10606030

  13. Lipid metabolism during encystment of Azotobacter vinelandii.

    PubMed Central

    Reusch, R N; Sadoff, H L

    1981-01-01

    The formation of cysts by Azotobacter vinelandii involves the synthesis of lipids as major metabolic products. Cells which encyst at low levels in aging glucose cultures undergo the same pattern of lipid synthesis as cells which undergo reasonably synchronous encystment in beta-hydroxybutyrate or n-butanol. The accumulation of poly-beta-hydroxybutyrate (PHB) precedes the synthesis of 5-n-heneicosylresorcinol and 5-n-tricosylresorcinol (AR1), which is then followed in about 6 h by the synthesis of the 5-n-alkylresorcinol galactosides (AR2). In the mature cyst, PHB, AR1, and AR2 account for 8, 5.6, and 4.5%, respectively, of the dry weight. Phospholipid formation levels off 4 h postinduction, which coincides with the final cell division, but fatty acids synthesis continues at a very low level throughout encystment, suggesting some turnover of fatty acid. Distribution studies show that AR1 and AR2 are found in roughly equal amounts in the exine and central body of the cysts, with only trace amounts recovered from the intine. Studies of cysts labeled during encystment with [14C]beta-hydroxybutyrate or during vegetative growth with [14C]glucose suggest that the exine structure is synthesized during encystment, but that the intine is composed largely of vegetative cell components. PMID:7462162

  14. Detection of bilayer lipid with graphene nanoribbon

    NASA Astrophysics Data System (ADS)

    Akbari, Elnaz; Buntat, Zolkafle; Afroozeh, Abdolkarim; Zeinalinezhad, Alireza; Nilashi, Mehrbakhsh

    2015-09-01

    Single-layer graphene consists of sp 2-bonded carbon atoms arranged in a two-dimensional (2D) hexagonal lattice comprising a thin layer of single carbon atoms. Owing to its special characteristics including electrical, physical, and optical properties, graphene is considered more suitable for sensor applications than other materials. Moreover, it is possible to produce biosensors using electrolyte-gated field-effect transistors based on graphene (GFETs) to identify the alterations in charged lipid membrane properties. This paper illustrates how membrane thickness and electrical charge can result in a monolayer GFET, with emphasis on conductance variation. It is proposed that the thickness and electrical charge of the lipid bilayer are functions of carrier density, and equations relating these suitable control parameters were derived. Adaptive neuro fuzzy inference system (ANFIS) has been incorporated to obtain other model for conductance characteristic. The comparison between the analytical models and ANFIS with the experimental data extracted from previous work show an acceptable agreement. [Figure not available: see fulltext.

  15. Lipid abnormalities in chronic renal failure.

    PubMed

    Bhagwat, R; Joshi, S P; Salgia, P; Sepaha, A

    1997-12-01

    Lipid abnormalities remain to be a major cause of early mortality in patients with chronic renal failure (CRF). In present study, 114 (one hundred fourteen) CRF patients without any additional cause of dyslipidemia were divided into groups on the basis of etiologies of CRF. Blood samples from each group were analyzed for total cholesterol, triglyceride and HDL cholesterol along with blood urea nitrogen and serum creatinine. 25 healthy individuals without any obvious disease were taken as control. Patients from all the groups showed a marked hypertriglyceridemia of 232 (SD±77) mg/dl (P<0.001) as compared to control. Levels of HDL cholesterol were found to be significantly low 20 (±11) mg/dl (p<0.001) in all the groups. LDL cholesterol showed an increase 104 (±30) mg/dl as compared to control group which is not statistically significant. Present study reveals that, CRF patients show an uniform dyslipidemia irrespective of etiologies leading to CRF. This dyslipidemia is also independent of serum creatinine levels. Although, these lipid abnormalities may not solely cause mortality in CRF patients, they may act as modulators in accelerating atherogenesis which in turn cause early mortality in CRF patients. PMID:23100870

  16. Ionic transport in lipid bilayer membranes.

    PubMed Central

    Bordi, F; Cametti, C; Naglieri, A

    1998-01-01

    The current-voltage relationships of model bilayer membranes have been measured in various phospholipid systems, under the influence of both a gradient of potential and an ionic concentration, in order to describe the ion translocation through hydrated transient defects (water channels) across the bilayer formed because of lipid structure fluctuations and induced by temperature. The results have been analyzed in the light of a statistical rate theory for the transport process across a lipid bilayer, recently proposed by Skinner et al. (1993). In order to take into account the observed I-V curves and in particular the deviation from an ohmic behavior observed at high potential values, the original model has been modified, and a new version has been proposed by introducing an additional kinetic process. In this way, a very good agreement with the experimental values has been obtained for all of the systems we have investigated (dimyristoylphosphatidyl ethanolamine bilayers and mixed systems composed by dimyristoylphosphatidyl ethanolamine/dimyristoylphosphatidylcholine mixtures and dimyristoylphosphatidyl ethanolamine/phosphatidic acid dipalmitoyl mixtures). The rate constants governing the reactions at the bilayer interfaces have been evaluated for K+ and Cl- ions, as a function of temperature, from 5 to 35 degrees C and bulk ionic concentrations from 0.02 to 0.2 M. Finally, a comparison between the original model of Skinner and the modified version is presented, and the advantages of this new formulation are briefly discussed. PMID:9512032

  17. Apolipoprotein E: from lipid transport to neurobiology.

    PubMed

    Hauser, Paul S; Narayanaswami, Vasanthy; Ryan, Robert O

    2011-01-01

    Apolipoprotein (apo) E has a storied history as a lipid transport protein. The integral association between cholesterol homeostasis and lipoprotein clearance from circulation are intimately related to apoE's function as a ligand for cell-surface receptors of the low-density lipoprotein receptor family. The receptor binding properties of apoE are strongly influenced by isoform specific amino acid differences as well as the lipidation state of the protein. As understanding of apoE as a structural component of circulating plasma lipoproteins has evolved, exciting developments in neurobiology have revitalized interest in apoE. The strong and enduring correlation between the apoE4 isoform and age of onset and increased risk of Alzheimer's disease has catapulted apoE to the forefront of neurobiology. Using genetic tools generated for study of apoE lipoprotein metabolism, transgenic "knock-in" and gene-disrupted mice are now favored models for study of its role in a variety of neurodegenerative diseases. Key structural knowledge of apoE and isoform-specific differences is driving research activity designed to elucidate how a single amino acid change can manifest such profoundly significant pathological consequences. This review describes apoE through a lens of structure-based knowledge that leads to hypotheses that attempt to explain the functions of apoE and isoform-specific effects relating to disease mechanism. PMID:20854843

  18. Structure of Cholesterol in Lipid Rafts

    NASA Astrophysics Data System (ADS)

    Toppozini, Laura; Meinhardt, Sebastian; Armstrong, Clare L.; Yamani, Zahra; Ku?erka, Norbert; Schmid, Friederike; Rheinstädter, Maikel C.

    2014-11-01

    Rafts, or functional domains, are transient nano-or mesoscopic structures in the plasma membrane and are thought to be essential for many cellular processes such as signal transduction, adhesion, trafficking, and lipid or protein sorting. Observations of these membrane heterogeneities have proven challenging, as they are thought to be both small and short lived. With a combination of coarse-grained molecular dynamics simulations and neutron diffraction using deuterium labeled cholesterol molecules, we observe raftlike structures and determine the ordering of the cholesterol molecules in binary cholesterol-containing lipid membranes. From coarse-grained computer simulations, heterogenous membranes structures were observed and characterized as small, ordered domains. Neutron diffraction was used to study the lateral structure of the cholesterol molecules. We find pairs of strongly bound cholesterol molecules in the liquid-disordered phase, in accordance with the umbrella model. Bragg peaks corresponding to ordering of the cholesterol molecules in the raftlike structures were observed and indexed by two different structures: a monoclinic structure of ordered cholesterol pairs of alternating direction in equilibrium with cholesterol plaques, i.e., triclinic cholesterol bilayers.

  19. The Structure of Cholesterol in Lipid Rafts

    E-print Network

    Laura Toppozini; Sebastian Meinhardt; Clare L. Armstrong; Zahra Yamani; Norbert Kucerka; Friederike Schmid; Maikel C. Rheinstaedter

    2014-12-16

    Rafts, or functional domains, are transient nano- or mesoscopic structures in the plasma membrane and are thought to be essential for many cellular processes such as signal transduction, adhesion, trafficking and lipid/protein sorting. Observations of these membrane heterogeneities have proven challenging, as they are thought to be both small and short-lived. With a combination of coarse-grained molecular dynamics simulations and neutron diffraction using deuterium labeled cholesterol molecules we observe raft-like structures and determine the ordering of the cholesterol molecules in binary cholesterol-containing lipid membranes. From coarse-grained computer simulations, heterogenous membranes structures were observed and characterized as small, ordered domains. Neutron diffraction was used to study the lateral structure of the cholesterol molecules. We find pairs of strongly bound cholesterol molecules in the liquid-disordered phase, in accordance with the umbrella model. Bragg peaks corresponding to ordering of the cholesterol molecules in the raft-like structures were observed and indexed by two different structures: a monoclinic structure of ordered cholesterol pairs of alternating direction in equilibrium with cholesterol plaques, i.e., triclinic cholesterol bilayers.

  20. Lipid Biosynthesis in Developing Mustard Seed

    PubMed Central

    Mukherjee, Kumar D.

    1983-01-01

    Cotyledons of developing mustard (Sinapis alba L.) seed have been found to synthesize lipids containing the common plant fatty acids and very long-chain monounsaturated (icosenoic, erucic, and tetracosenic) and saturated (icosanoic, docosanoic, and tetracosanoic) fatty acids from various radioactive precursors. The in vivo pattern of labeling of acyl lipids, either from fatty acids synthesized `endogenously' from radioactive acetate or malonate, or from radioactive fatty acids added `exogenously', indicates the involvement of the following pathways in the biosynthesis of triacylglycerols. Palmitic, stearic, and oleic acid, synthesized in the acyl carrier protein-track, are channeled to the Coenzyme A (CoA)-track and converted to triacylglycerols via the glycerol-3-phosphate pathway. Pools of stearoyl-CoA and oleoyl-CoA are elongated to very long-chain saturated and monounsaturated acyl-CoA, respectively. Most of the very long-chain saturated acyl-CoAs acylate preformed diacylglycerols. Very long-chain monounsaturated acyl-CoAs are converted to triacylglycerols, partly via phosphatidic acids and diacylglycerols, and partly by acylation of preformed diacylglycerols. PMID:16663345

  1. Photoacoustic imaging of human lymph nodes with endogenous lipid

    E-print Network

    Jones, Peter JS

    Photoacoustic imaging of human lymph nodes with endogenous lipid and hemoglobin contrast James A://spiedl.org/terms #12;Photoacoustic imaging of human lymph nodes with endogenous lipid and hemoglobin contrast James A, Gower Street, London WC1E 6BT, United Kingdom b University College London, Centre for Medical Imaging, 3

  2. Characterization of lipids in wheat grain as probed by microspectrofluorometry

    NASA Astrophysics Data System (ADS)

    Saadi, Abdelbasset; Piot, Olivier; Charonov, Serguei; Meunier, Jean-Claude; Manfait, Michel

    1999-05-01

    The baking quality and storage stability of white flour are affected by its non-starch lipids content, and by the proportions of non-polar and polar lipids classes. At present, information on the lipids composition in the various parts of the wheat grain is scarce and their redistribution in the flour millstreams after milling is not well understood. Here we have implemented a novel method based on microspectrofluorometry to investigate lipids distribution in the wheat kernel. This technique has already been a proven tool to study primary fluorescence in wheat grain. For this study Nile Red was introduced as a fluorescent stain to map lipids in different compartments of a wheat transverse section. Microspectrofluorometry allows in situ characterization of lipids material in transverse cut of wheat grain. Florescence spectra were recorded and decomposed into the principal spectral components which can in turn be approximated to the real lipid materials of the wheat. Using these models, spectral fluorescence imaging was performed allowing the spatial organization of lipids in the wheat sections to be obtained.

  3. Inverse-phosphocholine lipids: A remix of a common phospholipid

    PubMed Central

    Perttu, Emily K.; Kohli, Aditya G.; Szoka, Francis C.

    2012-01-01

    Zwitterionic inverse-phosphocholine (iPC) lipids contain headgroups with an inverted charge orientation relative to phosphocholine (PC) lipids. The iPC lipid headgroup has a quaternary amine adjacent to the bilayer and a phosphate that extends into the aqueous phase. Neutral iPC lipids with ethylated phosphate groups (CPe) and anionic iPC lipids non-ethylated phosphate groups (CP) were synthesized. The surface potential of CPe liposomes remains negative across a broad pH range and in the presence of up to 10 mM Ca2+. CP liposomes aggregate in the presence of Ca2+, but at a slower rate than other anionic lipids above 4 mM Ca2+ and are susceptible to hydrolysis by alkaline phosphatase which generates a cationic lipid. CPe liposomes release encapsulated anionic carboxyfluorescein (CF) twenty times more rapidly than PC liposomes, but only release uncharged glucose twice as fast. iPC lipids afford a unique opportunity to investigate the hiophysical and bioactivity-related ramifications of a charge inversion at the bilayer surface. PMID:22364493

  4. TRP channels interaction with lipids and its implications in disease.

    PubMed

    Taberner, Francisco J; Fernández-Ballester, Gregorio; Fernández-Carvajal, Asia; Ferrer-Montiel, Antonio

    2015-09-01

    Transient receptor potential (TRP) proteins are a family of ion channels central for sensory signaling. These receptors and, in particular, those involved in thermal sensing are also involved in pain signaling. Noteworthy, thermosensory receptors are polymodal ion channels that respond to both physical and chemical stimuli, thus integrating different environmental clues. In addition, their activity is modulated by algesic agents and lipidergic substances that are primarily released in pathological states. Lipids and lipid-like molecules have been found that can directly activate some thermosensory channels or modulate their activity by either potentiating or inhibiting it. To date, more than 50 endogenous lipids that can regulate TRP channel activity in sensory neurons have been described, thus representing the majority of known endogenous TRP channel modulators. Lipid modulators of TRP channels comprise lipids from a variety of metabolic pathways, including metabolites of the cyclooxygenase, lipoxygenase and cytochrome-P450 pathways, phospholipids and lysophospholipids. Therefore, TRP-channels are able to integrate and interpret incoming signals from the different metabolic lipid pathways. Taken together, the large number of lipids that can activate, sensitize or inhibit neuronal TRP-channels highlights the pivotal role of these molecules in sensory biology as well as in pain transduction and perception. This article is part of a Special Issue entitled: Lipid-protein interactions. Guest Editors: Amitabha Chattopadhyay and Jean-Marie Ruysschaert. PMID:25838124

  5. Diurnal regulation of lipid metabolism and applications of circadian lipidomics.

    PubMed

    Gooley, Joshua J; Chua, Eric Chern-Pin

    2014-05-20

    The circadian timing system plays a key role in orchestrating lipid metabolism. In concert with the solar cycle, the circadian system ensures that daily rhythms in lipid absorption, storage, and transport are temporally coordinated with rest-activity and feeding cycles. At the cellular level, genes involved in lipid synthesis and fatty acid oxidation are rhythmically activated and repressed by core clock proteins in a tissue-specific manner. Consequently, loss of clock gene function or misalignment of circadian rhythms with feeding cycles (e.g., in shift work) results in impaired lipid homeostasis. Herein, we review recent progress in circadian rhythms research using lipidomics, i.e., large-scale profiling of lipid metabolites, to characterize circadian-regulated lipid pathways in mammals. In mice, novel regulatory circuits involved in fatty acid metabolism have been identified in adipose tissue, liver, and muscle. Extensive diversity in circadian regulation of plasma lipids has also been revealed in humans using lipidomics and other metabolomics approaches. In future studies, lipidomics platforms will be increasingly used to better understand the effects of genetic variation, shift work, food intake, and drugs on circadian-regulated lipid pathways and metabolic health. PMID:24894351

  6. STARCH-LIPID COMPOSITES IN PLAIN SET YOGURT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-lipid composites (0.5, 1, 2, 3, and 4%) were used to replace milk solids (5, 10, 20, 30, 40%) in yogurt mixes. The effects of the starch-lipid composites on the yogurt fermentations and rheology were studied. The rate of fermentation was evaluated by the change of pH every two minutes durin...

  7. Non-aqueous microchip electrophoresis for characterization of lipid biomarkers

    PubMed Central

    Gibson, Larry R.; Bohn, Paul W.

    2013-01-01

    In vivo measurements of lipid biomarkers are hampered by their low solubility in aqueous solution, which limits the choices for molecular separations. Here, we introduce non-aqueous microchip electrophoretic separations of lipid mixtures performed in three-dimensional hybrid nanofluidic/microfluidic polymeric devices. Electrokinetic injection is used to reproducibly introduce discrete femtolitre to picolitre volumes of charged lipids into a separation microchannel containing low (100 ?M–10 mM) concentration tetraalkylammonium tetraphenylborate background electrolyte (BGE) in N-methylformamide, supporting rapid electro-osmotic fluid flow in polydimethylsiloxane microchannels. The quality of the resulting electrophoretic separations depends on the voltage and timing of the injection pulse, the BGE concentration and the electric field strength. Injected volumes increase with longer injection pulse widths and higher injection pulse amplitudes. Separation efficiency, as measured by total plate number, N, increases with increasing electric field and with decreasing BGE concentration. Electrophoretic separations of binary and ternary lipid mixtures were achieved with high resolution (Rs ? 5) and quality (N > 7.7 × 106 plates m?1). Rapid in vivo monitoring of lipid biomarkers requires high-quality separation and detection of lipids downstream of microdialysis sample collection, and the multilayered non-aqueous microfluidic devices studied here offer one possible avenue to swiftly process complex lipid samples. The resulting capability may make it possible to correlate oxidative stress with in vivo lipid biomarker levels. PMID:24427539

  8. Using residual lipid to assess rice degree of milling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Color is often used to measure the degree of milling of rice. Milled rice color is determined by the adhering, pigmented bran. Bran and germ are successively removed during milling and those tissues contain large quantities of lipid, therefore, surface lipid content may be used to assess milling qua...

  9. Monoubiquitination of Ancient Ubiquitous Protein 1 Promotes Lipid Droplet Clustering

    PubMed Central

    Lohmann, Daniel; Spandl, Johanna; Stevanovic, Ana; Schoene, Mario; Philippou-Massier, Julia; Thiele, Christoph

    2013-01-01

    Lipid droplets, the intracellular storage organelles for neutral lipids, exist in a wide range of sizes and of morphologically distinct organization, from loosely dispersed lipid droplets to tightly packed lipid droplet clusters. We show that the lipid droplet protein AUP1 induces cluster formation. A fraction of AUP1 is monoubiquitinated at various lysine residues. This process depends on its internal CUE domain, which is a known ubiquitin-binding domain. AUP1 with a deleted or point mutagenized CUE domain, as well as a lysine-free mutant, are not ubiquitinated and do not induce lipid droplet clustering. When such ubiquitination deficient mutants are fused to ubiquitin, clustering is restored. AUP1 mutants with defective droplet targeting fail to induce clustering. Also, another lipid droplet protein, NSDHL, with a fused ubiquitin does not induce clustering. The data indicate that monoubiquitinated AUP1 on the lipid droplet surface specifically induces clustering, and suggest a homophilic interaction with a second AUP1 molecule or a heterophilic interaction with another ubiquitin-binding protein. PMID:24039768

  10. Monoubiquitination of ancient ubiquitous protein 1 promotes lipid droplet clustering.

    PubMed

    Lohmann, Daniel; Spandl, Johanna; Stevanovic, Ana; Schoene, Mario; Philippou-Massier, Julia; Thiele, Christoph

    2013-01-01

    Lipid droplets, the intracellular storage organelles for neutral lipids, exist in a wide range of sizes and of morphologically distinct organization, from loosely dispersed lipid droplets to tightly packed lipid droplet clusters. We show that the lipid droplet protein AUP1 induces cluster formation. A fraction of AUP1 is monoubiquitinated at various lysine residues. This process depends on its internal CUE domain, which is a known ubiquitin-binding domain. AUP1 with a deleted or point mutagenized CUE domain, as well as a lysine-free mutant, are not ubiquitinated and do not induce lipid droplet clustering. When such ubiquitination deficient mutants are fused to ubiquitin, clustering is restored. AUP1 mutants with defective droplet targeting fail to induce clustering. Also, another lipid droplet protein, NSDHL, with a fused ubiquitin does not induce clustering. The data indicate that monoubiquitinated AUP1 on the lipid droplet surface specifically induces clustering, and suggest a homophilic interaction with a second AUP1 molecule or a heterophilic interaction with another ubiquitin-binding protein. PMID:24039768

  11. Algal Lipid Extraction and Upgrading to Hydrocarbons Technology Pathway

    SciTech Connect

    Davis, R.; Biddy, M.; Jones, S.

    2013-03-01

    This technology pathway case investigates the cultivation of algal biomass followed by further lipid extraction and upgrading to hydrocarbon biofuels. Technical barriers and key research needs have been assessed in order for the algal lipid extraction and upgrading pathway to be competitive with petroleum-derived gasoline-, diesel-, and jet-range hydrocarbon blendstocks.

  12. Lipid bilayer and cytoskeletal interactions in a red Zhangli Penga

    E-print Network

    Dao, Ming

    pathological conditions, e.g., in sickle cell disease, the cytoskeleton may become disso- ciated from the lipid a basis for further studies to probe cell mechanistic processes in health and disease in a mannerLipid bilayer and cytoskeletal interactions in a red blood cell Zhangli Penga , Xuejin Lib , Igor V

  13. Charge-induced phase separation in lipid membranes.

    PubMed

    Himeno, Hiroki; Shimokawa, Naofumi; Komura, Shigeyuki; Andelman, David; Hamada, Tsutomu; Takagi, Masahiro

    2014-10-28

    Phase separation in lipid bilayers that include negatively charged lipids is examined experimentally. We observed phase-separated structures and determined the membrane miscibility temperatures in several binary and ternary lipid mixtures of unsaturated neutral lipid, dioleoylphosphatidylcholine (DOPC), saturated neutral lipid, dipalmitoylphosphatidylcholine (DPPC), unsaturated charged lipid, dioleoylphosphatidylglycerol (DOPG((-))), saturated charged lipid, dipalmitoylphosphatidylglycerol (DPPG((-))), and cholesterol. In binary mixtures of saturated and unsaturated charged lipids, the combination of the charged head with the saturation of the hydrocarbon tail is a dominant factor in the stability of membrane phase separation. DPPG((-)) enhances phase separation, while DOPG((-)) suppresses it. Furthermore, the addition of DPPG((-)) to a binary mixture of DPPC/cholesterol induces phase separation between DPPG((-))-rich and cholesterol-rich phases. This indicates that cholesterol localization depends strongly on the electric charge on the hydrophilic head group rather than on the ordering of the hydrocarbon tails. Finally, when DPPG((-)) was added to a neutral ternary system of DOPC/DPPC/cholesterol (a conventional model of membrane rafts), a three-phase coexistence was produced. We conclude by discussing some qualitative features of the phase behaviour in charged membranes using a free energy approach. PMID:25154325

  14. Reaction of ferritin with hydrogen peroxide induces lipid peroxidation.

    PubMed

    Yoon, Jung Hwan; Lee, Myeong Seon; Kang, Jung Hoon

    2010-03-01

    Lipid peroxidation is known to be an important factor in the pathologies of many diseases associated with oxidative stress. We assessed the lipid peroxidation induced by the reaction of ferritin with H2O2. When linoleic acid micelles or phosphatidyl choline liposomes were incubated with ferritin and H2O2, lipid peroxidation increased in the presence of ferritin and H2O2 in a concentration-dependent manner. The hydroxyl radical scavengers, azide and thiourea, prevented lipid peroxidation induced by the ferritin/H2O2 system. The iron specific chelator desferoxamine also prevented ferritin/H2O2 systemmediated lipid peroxidation. These results demonstrate the possible role of iron in ferritin/H2O2 system-mediated lipid peroxidation. Carnosine is involved in many cellular defense processes, including free radical detoxification. In this study, carnosine, homocarnosine, and anserine were shown to significantly prevent ferritin/H2O2 system-mediated lipid peroxidation and also inhibited the free radical-generation activity of ferritin. These results indicated that carnosine and related compounds may prevent ferritin/H2O2 system-mediated lipid peroxidation via free radical scavenging. PMID:20356464

  15. Mapping lipid and collagen by multispectral photoacoustic imaging of

    E-print Network

    Cheng, Ji-Xin

    Mapping lipid and collagen by multispectral photoacoustic imaging of chemical bond vibration Pu Wang Ping Wang Han-Wei Wang Ji-Xin Cheng #12;Mapping lipid and collagen by multispectral photoacoustic, Department of Chemistry, West Lafayette, Indiana 47907 Abstract. Photoacoustic microscopy using vibrational

  16. Two-Component Membrane Lithography via Lipid Backfilling

    E-print Network

    ] and voids following either resist lift-off[9­11] or photo-oxidative degradation of lipids.[12] Patterning lithographic technique to pattern artificial lipid bilayer microdomains by ex- ploiting the limited mobility barriers, such as metals or metal oxides,[5] proteins,[6,7] photoresist,[8] mechanical scratches,[7

  17. Biogenesis and functions of lipid droplets in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The compartmentation of neutral lipids in plant tissues is mostly associated with seed tissues, where triacylglycerols (TAGs) stored within lipid droplets (LDs) serve as an essential physiological energy and carbon reserve during post-germinative growth. However, some non-seed tissues, such as leave...

  18. Lipids at the interface of virus-host interactions

    PubMed Central

    Chukkapalli, Vineela; Heaton, Nicholas S.; Randall, Glenn

    2012-01-01

    Viruses physically and metabolically remodel the host cell to establish an optimal environment for their replication. Many of these processes involve the manipulation of lipid signaling, synthesis and metabolism. An emerging theme is that these lipid-modifying pathways are also linked to innate anti-viral responses and can be modulated to inhibit viral replication. PMID:22682978

  19. Antioxidant effect of bisphosphonates and simvastatin on chondrocyte lipid peroxidation

    SciTech Connect

    Dombrecht, E.J.; De Tollenaere, C.B.; Aerts, K.; Cos, P.; Schuerwegh, A.J.; Bridts, C.H.; Van Offel, J.F.; Ebo, D.G.; Stevens, W.J. . E-mail: immuno@ua.ac.be; De Clerck, L.S.

    2006-09-22

    The objective of this study was to evaluate the effect of bisphosphonates (BPs) and simvastatin on chondrocyte lipid peroxidation. For this purpose, a flow cytometrical method using C11-BODIPY{sup 581/591} was developed to detect hydroperoxide-induced lipid peroxidation in chondrocytes. Tertiary butylhydroperoxide (t-BHP) induced a time and concentration dependent increase in chondrocyte lipid peroxidation. Addition of a Fe{sup 2+}/EDTA complex to t-BHP or hydrogen peroxide (H{sub 2}O{sub 2}) clearly enhanced lipid peroxidation. The lipophilic simvastatin demonstrated a small inhibition in the chondrocyte lipid peroxidation. None of three tested BPs (clodronate, pamidronate, and risedronate) had an effect on chondrocyte lipid peroxidation induced by t-BHP. However, when Fe{sup 2+}/EDTA complex was added to t-BHP or H{sub 2}O{sub 2}, BPs inhibited the lipid peroxidation process varying from 25% to 58%. This study demonstrates that BPs have antioxidant properties as iron chelators, thereby inhibiting the chondrocyte lipid peroxidation. These findings add evidence to the therapeutic potential of bisphosphonates and statins in rheumatoid arthritis.

  20. PARTICLE SIZE CHARACTERIZATION OF STARCH-LIPID COMPOSITES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-lipid composites (SLCs) have been used as fat replacers and stabilizers in beef patties, dairy products, and baked goods and the technology has been patented under the trademark FanteskTM. The SLCs are produced by mixing aqueous starch slurry with a lipid source, and steam jet-cooking. The ...

  1. LIPID COMPOSITION OF OVERWINTERING ALFALFA LEAFCUTTING BEE PREPUPAE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alfalfa leafcutting bees, Megachile rotundata (F.) overwinter as prepupae. The cuticular and internal lipids were extracted from prepupae that had been held at 4 C for eight months. Cuticular lipid components were separated, identified and quantitated by capillary gas chromatography (CGC) and CGC-m...

  2. Phytotoxic Activity of Quinone and Resorcinolic Lipid Derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Based on the phytotoxic activity of sorgoleone and resorcinolic lipids identified from the roots extracts of sorghum, 8 resorcinolic lipids derivatives and 10 quinones with varying side chains size were synthesized. The compounds were submitted to phtotoxicity assay against monocot and dicot species...

  3. Disruption of cell walls for enhanced lipid recovery

    DOEpatents

    Knoshaug, Eric P; Donohoe, Bryon S; Gerken, Henri; Laurens, Lieve; Van Wychen, Stefanie Rose

    2015-03-24

    Presented herein are methods of using cell wall degrading enzymes for recovery of internal lipid bodies from biomass sources such as algae. Also provided are algal cells that express at least one exogenous gene encoding a cell wall degrading enzyme and methods for recovering lipids from the cells.

  4. Structural studies of lipid-protein interactions on cushioned bilayers

    NASA Astrophysics Data System (ADS)

    Ghosh, S. K.; Mukhopadhyay, M. K.; Ma, Y.; Lopez, I.; Bera, S.; Lurio, L. B.; Chakrabarti, A.; Kim, J. E.; Sanyal, M. K.; Sinha, S. K.

    2013-03-01

    Biological membranes are heterogeneous and dynamical organizations of lipids and proteins, which perform functions fundamental to cell survival. Lipid-protein interactions control these functions by influencing folding and stability of integral or peripheral membrane proteins. Further, the incorporation or adsorption of these proteins into the membrane can in turn influence the lipid bilayer properties. In spite of some progress in understanding this process, a detailed structural analysis is lacking. Towards a better understanding of this interaction, we have performed an advanced interface sensitive scattering experiment using synchrotron x-rays. To accurately mimic the biological membranes with their natural thermal fluctuations and in-plane mobility of lipid molecules, polymer cushioned lipid bilayers have been used. This study shows that the adsorption of peripheral membrane proteinspectrindepends on the lipid headgroups, exhibiting different types of binding to phosphatidylcholine (PC) and phosphatidylethanolamie (PE). Further, the interaction of outer membrane protein A (OMP-A), an integral membrane protein is sensitive to the thermodynamic phase of the lipids. A detailed physical modeling of the lipid-protein interactions is under way.

  5. Giant Unilamelar Vesicles preparation protocol -Nanion Chips Lipid stock solution

    E-print Network

    Movileanu, Liviu

    Giant Unilamelar Vesicles ­ preparation protocol - Nanion Chips Lipid stock solution: · 2.5mg)(Ammonium Salt) (Avanti)) ­ only if fluorescence microscope is used. Sucrose stock solution: · 300mM Sucrose: On the electrodes system 1.5µl drops form lipid stock solution were added at 5 different places on each electrode

  6. Lipid Analysis of Neochloris oleoabundans by Liquid State NMR

    E-print Network

    for biodiesel production. To demonstrate the viability of this approach, 13 C NMR was used to analyze the lipid relevance to biodiesel production. Biotechnol. Bioeng. 2010;106: 573­583. ß 2010 Wiley Periodicals, Inc. KEYWORDS: NMR; algae; lipid; triglyceride; composition analysis; biodiesel Introduction Biodiesel produced

  7. Lipid Rafts and Caveolae in Signaling by Growth Factor Receptors

    PubMed Central

    de Laurentiis, Angela; Donovan, Lorna; Arcaro, Alexandre

    2007-01-01

    Lipid rafts and caveolae are microdomains of the plasma membrane enriched in sphingolipids and cholesterol, and hence are less fluid than the remainder of the membrane. Caveolae have an invaginated structure, while lipid rafts are flat regions of the membrane. The two types of microdomains have different protein compositions (growth factor receptors and their downstream molecules) suggesting that lipid rafts and caveolae have a role in the regulation of signaling by these receptors. The purpose of this review is to discuss this model, and the implications that it might have regarding a potential role for lipid rafts and caveolae in human cancer. Particular attention will be paid to the epidermal growth factor receptor, for which the largest amount of information is available. It has been proposed that caveolins act as tumor suppressors. The role of lipid rafts is less clear, but they seem to be capable of acting as ‘signaling platforms’, in which signal initiation and propagation can occur efficiently. PMID:18949068

  8. Effects of a bacterial trehalose lipid on phosphatidylglycerol membranes.

    PubMed

    Ortiz, Antonio; Teruel, José A; Manresa, Ángeles; Espuny, María J; Marqués, Ana; Aranda, Francisco J

    2011-08-01

    Bacterial trehalose lipids are biosurfactants with potential application in the biomedical/healthcare industry due to their interesting biological properties. Given the amphiphilic nature of trehalose lipids, the understanding of the molecular mechanism of their biological action requires that the interaction between biosurfactant and membranes is known. In this study we examine the interactions between a trehalose lipid from Rhodococcus sp. and dimyristoylphosphatidylglycerol membranes by means of differential scanning calorimetry, X-ray diffraction, infrared spectroscopy and fluorescence polarization. We report that there are extensive interactions between trehalose lipid and dimyristoylphosphatidylglycerol involving the perturbation of the thermotropic gel to liquid-crystalline phase transition of the phospholipid, the increase of fluidity of the phosphatidylglycerol acyl chains and dehydration of the interfacial region of the bilayer, and the modulation of the order of the phospholipid bilayer. The observations are interpreted in terms of structural perturbations affecting the function of the membrane that might underline the biological actions of the trehalose lipid. PMID:21600191

  9. Global profiling of protein lipidation using chemical proteomic technologies

    PubMed Central

    Tate, Edward W; Kalesh, Karunakaran A; Lanyon-Hogg, Thomas; Storck, Elisabeth M; Thinon, Emmanuelle

    2015-01-01

    Protein lipidation is unique amongst post-translational modifications (PTMs) in enabling direct interaction with cell membranes, and is found in every form of life. Lipidation is important in normal function and in disease, but its intricate interplay with disease context presents a challenging for drug development. Global whole-proteome profiling of protein lipidation lies beyond the range of standard methods, but is well-suited to metabolic tagging with small ‘clickable’ chemical reporters that do not disrupt metabolism and function; chemoselective reactions are then used to add multifunctional labels exclusively to tagged-lipidated proteins. This chemical proteomic technology has opened up the first quantitative whole-proteome studies of the known major classes of protein lipidation, and the first insights into their full scope in vivo. PMID:25461723

  10. A Lipid Gate for the Peripheral Control of Pain

    PubMed Central

    Hohmann, Andrea G.; Seybold, Virginia; Hammock, Bruce D.

    2014-01-01

    Cells in injured and inflamed tissues produce a number of proalgesic lipid-derived mediators, which excite nociceptive neurons by activating selective G-protein-coupled receptors or ligand-gated ion channels. Recent work has shown that these proalgesic factors are counteracted by a distinct group of lipid molecules that lower nociceptor excitability and attenuate nociception in peripheral tissues. Analgesic lipid mediators include endogenous agonists of cannabinoid receptors (endocannabinoids), lipid-amide agonists of peroxisome proliferator-activated receptor-?, and products of oxidative metabolism of polyunsaturated fatty acids via cytochrome P450 and other enzyme pathways. Evidence indicates that these lipid messengers are produced and act at different stages of inflammation and the response to tissue injury, and may be part of a peripheral gating mechanism that regulates the access of nociceptive information to the spinal cord and the brain. Growing knowledge about this peripheral control system may be used to discover safer medicines for pain. PMID:25392487

  11. A lipid gate for the peripheral control of pain.

    PubMed

    Piomelli, Daniele; Hohmann, Andrea G; Seybold, Virginia; Hammock, Bruce D

    2014-11-12

    Cells in injured and inflamed tissues produce a number of proalgesic lipid-derived mediators, which excite nociceptive neurons by activating selective G-protein-coupled receptors or ligand-gated ion channels. Recent work has shown that these proalgesic factors are counteracted by a distinct group of lipid molecules that lower nociceptor excitability and attenuate nociception in peripheral tissues. Analgesic lipid mediators include endogenous agonists of cannabinoid receptors (endocannabinoids), lipid-amide agonists of peroxisome proliferator-activated receptor-?, and products of oxidative metabolism of polyunsaturated fatty acids via cytochrome P450 and other enzyme pathways. Evidence indicates that these lipid messengers are produced and act at different stages of inflammation and the response to tissue injury, and may be part of a peripheral gating mechanism that regulates the access of nociceptive information to the spinal cord and the brain. Growing knowledge about this peripheral control system may be used to discover safer medicines for pain. PMID:25392487

  12. Lipid releasing characteristics of microalgae species through continuous ultrasonication.

    PubMed

    Natarajan, Ramya; Ang, Wei Ming Russell; Chen, Xue; Voigtmann, Michael; Lau, Raymond

    2014-04-01

    In this study, the lipid releasing characteristics of several microalgae species through continuous ultrasonication was examined. Two marine microalgae species, Tetraselmis suecica and Nannochloropsis sp., and one freshwater species, Chlorella sp. were ultrasonicated directly after cultivation. The cell disruption efficiency and lipids releasing pattern from microalgae cells were measured under various ultrasonication conditions. It was found that cell disruption efficiency correlates well with ultrasonication energy consumption despite the ultrasonication conditions. Lipids in Chlorella sp. that has rigid cell walls were released to the aqueous phase after cell disruption. T. suecica and Nannochloropsis sp. that have flexible cell membranes tend to coil up and retain the membrane lipids after disruption. Continuous ultrasonication can be a potential method to release the lipids in rigid walled microalgae species without expensive dewatering steps. PMID:24583912

  13. Lipid patterns in the saliva of smoking young adults.

    PubMed

    Palmerini, C A; Saccardi, C; Ferracci, F; Arienti, S

    2011-10-01

    Salivary lipids are important for the maintenance of oral cavity health. Elevated salivary lipid levels are associated with an increase of caries incidence, plaque development, calculus formation and periodontal disease. However, the regulation of lipid salivary levels is scarcely known. Cigarette smoke is considered a risk factor for oral cavity diseases. We study how cigarette smoke may affect the secretion of salivary lipids. To this purpose, we determine the salivary levels of cholesterol and of glycerolipids in saliva sampled from smokers and non-smokers at various times of day. We observe an increase of glycerophospholipid and a decrease of cholesterol levels in the smokers' saliva collected at 10 p.m. On the other hand, unsaturated fatty acids in chief phospholipids of saliva are lower in smokers at 7 a.m. Therefore, for the first time, we demonstrate that cigarette smoke induces variations of saliva lipid pattern in young people even moderately smoking. PMID:21300688

  14. Discovery and Refinement of Loci Associated with Lipid Levels

    PubMed Central

    Peloso, Gina M.; Gustafsson, Stefan; Kanoni, Stavroula; Ganna, Andrea; Chen, Jin; Buchkovich, Martin L.; Mora, Samia; Beckmann, Jacques S.; Bragg-Gresham, Jennifer L.; Chang, Hsing-Yi; Demirkan, Ay?e; Den Hertog, Heleen M.; Do, Ron; Donnelly, Louise A.; Ehret, Georg B.; Esko, Tõnu; Feitosa, Mary F.; Ferreira, Teresa; Fischer, Krista; Fontanillas, Pierre; Fraser, Ross M.; Freitag, Daniel F.; Gurdasani, Deepti; Heikkilä, Kauko; Hyppönen, Elina; Isaacs, Aaron; Jackson, Anne U.; Johansson, Åsa; Johnson, Toby; Kaakinen, Marika; Kettunen, Johannes; Kleber, Marcus E.; Li, Xiaohui; Luan, Jian’an; Lyytikäinen, Leo-Pekka; Magnusson, Patrik K.E.; Mangino, Massimo; Mihailov, Evelin; Montasser, May E.; Müller-Nurasyid, Martina; Nolte, Ilja M.; O’Connell, Jeffrey R.; Palmer, Cameron D.; Perola, Markus; Petersen, Ann-Kristin; Sanna, Serena; Saxena, Richa; Service, Susan K.; Shah, Sonia; Shungin, Dmitry; Sidore, Carlo; Song, Ci; Strawbridge, Rona J.; Surakka, Ida; Tanaka, Toshiko; Teslovich, Tanya M.; Thorleifsson, Gudmar; Van den Herik, Evita G.; Voight, Benjamin F.; Volcik, Kelly A.; Waite, Lindsay L.; Wong, Andrew; Wu, Ying; Zhang, Weihua; Absher, Devin; Asiki, Gershim; Barroso, Inês; Been, Latonya F.; Bolton, Jennifer L.; Bonnycastle, Lori L; Brambilla, Paolo; Burnett, Mary S.; Cesana, Giancarlo; Dimitriou, Maria; Doney, Alex S.F.; Döring, Angela; Elliott, Paul; Epstein, Stephen E.; Ingi Eyjolfsson, Gudmundur; Gigante, Bruna; Goodarzi, Mark O.; Grallert, Harald; Gravito, Martha L.; Groves, Christopher J.; Hallmans, Göran; Hartikainen, Anna-Liisa; Hayward, Caroline; Hernandez, Dena; Hicks, Andrew A.; Holm, Hilma; Hung, Yi-Jen; Illig, Thomas; Jones, Michelle R.; Kaleebu, Pontiano; Kastelein, John J.P.; Khaw, Kay-Tee; Kim, Eric; Klopp, Norman; Komulainen, Pirjo; Kumari, Meena; Langenberg, Claudia; Lehtimäki, Terho; Lin, Shih-Yi; Lindström, Jaana; Loos, Ruth J.F.; Mach, François; McArdle, Wendy L; Meisinger, Christa; Mitchell, Braxton D.; Müller, Gabrielle; Nagaraja, Ramaiah; Narisu, Narisu; Nieminen, Tuomo V.M.; Nsubuga, Rebecca N.; Olafsson, Isleifur; Ong, Ken K.; Palotie, Aarno; Papamarkou, Theodore; Pomilla, Cristina; Pouta, Anneli; Rader, Daniel J.; Reilly, Muredach P.; Ridker, Paul M.; Rivadeneira, Fernando; Rudan, Igor; Ruokonen, Aimo; Samani, Nilesh; Scharnagl, Hubert; Seeley, Janet; Silander, Kaisa; Stan?áková, Alena; Stirrups, Kathleen; Swift, Amy J.; Tiret, Laurence; Uitterlinden, Andre G.; van Pelt, L. Joost; Vedantam, Sailaja; Wainwright, Nicholas; Wijmenga, Cisca; Wild, Sarah H.; Willemsen, Gonneke; Wilsgaard, Tom; Wilson, James F.; Young, Elizabeth H.; Zhao, Jing Hua; Adair, Linda S.; Arveiler, Dominique; Assimes, Themistocles L.; Bandinelli, Stefania; Bennett, Franklyn; Bochud, Murielle; Boehm, Bernhard O.; Boomsma, Dorret I.; Borecki, Ingrid B.; Bornstein, Stefan R.; Bovet, Pascal; Burnier, Michel; Campbell, Harry; Chakravarti, Aravinda; Chambers, John C.; Chen, Yii-Der Ida; Collins, Francis S.; Cooper, Richard S.; Danesh, John; Dedoussis, George; de Faire, Ulf; Feranil, Alan B.; Ferrières, Jean; Ferrucci, Luigi; Freimer, Nelson B.; Gieger, Christian; Groop, Leif C.; Gudnason, Vilmundur; Gyllensten, Ulf; Hamsten, Anders; Harris, Tamara B.; Hingorani, Aroon; Hirschhorn, Joel N.; Hofman, Albert; Hovingh, G. Kees; Hsiung, Chao Agnes; Humphries, Steve E.; Hunt, Steven C.; Hveem, Kristian; Iribarren, Carlos; Järvelin, Marjo-Riitta; Jula, Antti; Kähönen, Mika; Kaprio, Jaakko; Kesäniemi, Antero; Kivimaki, Mika; Kooner, Jaspal S.; Koudstaal, Peter J.; Krauss, Ronald M.; Kuh, Diana; Kuusisto, Johanna; Kyvik, Kirsten O.; Laakso, Markku; Lakka, Timo A.; Lind, Lars; Lindgren, Cecilia M.; Martin, Nicholas G.; März, Winfried; McCarthy, Mark I.; McKenzie, Colin A.; Meneton, Pierre; Metspalu, Andres; Moilanen, Leena; Morris, Andrew D.; Munroe, Patricia B.; Njølstad, Inger; Pedersen, Nancy L.; Power, Chris; Pramstaller, Peter P.; Price, Jackie F.; Psaty, Bruce M.; Quertermous, Thomas; Rauramaa, Rainer; Saleheen, Danish; Salomaa, Veikko; Sanghera, Dharambir K.; Saramies, Jouko; Schwarz, Peter E.H.; Sheu, Wayne H-H; Shuldiner, Alan R.; Siegbahn, Agneta; Spector, Tim D.; Stefansson, Kari; Strachan, David P.; Tayo, Bamidele O.; Tremoli, Elena; Tuomilehto, Jaakko; Uusitupa, Matti; van Duijn, Cornelia M.; Vollenweider, Peter; Wallentin, Lars; Wareham, Nicholas J.; Whitfield, John B.; Wolffenbuttel, Bruce H.R.; Ordovas, Jose M.; Boerwinkle, Eric; Palmer, Colin N.A.

    2013-01-01

    Low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, and total cholesterol are heritable, modifiable, risk factors for coronary artery disease. To identify new loci and refine known loci influencing these lipids, we examined 188,578 individuals using genome-wide and custom genotyping arrays. We identify and annotate 157 loci associated with lipid levels at P < 5×10?8, including 62 loci not previously associated with lipid levels in humans. Using dense genotyping in individuals of European, East Asian, South Asian, and African ancestry, we narrow association signals in 12 loci. We find that loci associated with blood lipids are often associated with cardiovascular and metabolic traits including coronary artery disease, type 2 diabetes, blood pressure, waist-hip ratio, and body mass index. Our results illustrate the value of genetic data from individuals of diverse ancestries and provide insights into biological mechanisms regulating blood lipids to guide future genetic, biological, and therapeutic research. PMID:24097068

  15. Lipid-Based Therapy for Ocular Surface Inflammation and Disease.

    PubMed

    Lim, Agnes; Wenk, Markus R; Tong, Louis

    2015-12-01

    Ocular surface diseases such as dry eye, allergic keratoconjunctivitis, and infection are very prevalent conditions and involve ocular surface stress and inflammation. Recently, various lipid-based therapies have been advocated for the modulation of ocular surface inflammation. Here we review the latest developments and challenges of these strategies. These include administration of essential fatty acids, cyclooxygenase (COX) inhibitors and resolvin analogs. Lipids form part of the tear film and are crucial for tear film stability; loss of tear film stability can aggravate ocular surface inflammation. Strategies to replenish tear film lipids - namely, eyelid warming and eye drops containing natural or synthetic lipids - are evaluated. Recent advances in the use of lipids as ocular drug delivery vehicles, antioxidants, and diagnostic markers are discussed. PMID:26596867

  16. SAXS Study of Sterically Stabilized Lipid Nanocarriers Functionalized by DNA

    NASA Astrophysics Data System (ADS)

    Angelov, Borislav; Angelova, Angelina; Filippov, Sergey; Karlsson, Göran; Terrill, Nick; Lesieur, Sylviane; Št?pánek, Petr

    2012-03-01

    The structure of novel spontaneously self-assembled plasmid DNA/lipid complexes is investigated by means of synchrotron radiation small-angle X-ray scattering (SAXS) and Cryo-TEM imaging. Liquid crystalline (LC) hydrated lipid systems are prepared using the non-ionic lipids monoolein and DOPE-PEG2000 and the cationic amphiphile CTAB. The employed plasmid DNA (pDNA) is encoding for the human protein brain-derived neurotrophic factor (BDNF). A coexistence of nanoparticulate objects with different LC inner organizations is established. A transition from bicontinuous membrane sponges, cubosome intermediates and unilamelar liposomes to multilamellar vesicles, functionalized by pDNA, is favoured upon binding and compaction of pBDNF onto the cationic PEGylated lipid nanocarriers. The obtained sterically stabilized multicompartment nanoobjects, with confined supercoiled plasmid DNA (pBDNF), are important in the context of multicompartment lipid nanocarriers of interest for gene therapy of neurodegenerative diseases.

  17. Performance of structured lipids incorporating selected phenolic and ascorbic acids.

    PubMed

    Gruczynska, Eliza; Przybylski, Roman; Aladedunye, Felix

    2015-04-15

    Conditions applied during frying require antioxidant which is stable at these conditions and provides protection for frying oil and fried food. Novel structured lipids containing nutraceuticals and antioxidants were formed by enzymatic transesterification, exploring canola oil and naturally occurring antioxidants such as ascorbic and selected phenolic acids as substrates. Lipozyme RM IM lipase from Rhizomucor miehei was used as biocatalyst. Frying performance and oxidative stability of the final transesterification products were evaluated. The novel lipids showed significantly improved frying performance compared to canola oil. Oxidative stability assessment of the structured lipids showed significant improvement in resistance to oxidative deterioration compared to original canola oil. Interestingly, the presence of ascorbic acid in an acylglycerol structure protected ?-tocopherol against thermal degradation, which was not observed for the phenolic acids. Developed structured lipids containing nutraceuticals and antioxidants may directly affect nutritional properties of lipids also offering nutraceutical ingredients for food formulation. PMID:25466089

  18. Lipid Transport between the Endoplasmic Reticulum and Mitochondria

    PubMed Central

    Flis, Vid V.

    2013-01-01

    Mitochondria are partially autonomous organelles that depend on the import of certain proteins and lipids to maintain cell survival and membrane formation. Although phosphatidylglycerol, cardiolipin, and phosphatidylethanolamine are synthesized by mitochondrial enzymes, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, and sterols need to be imported from other organelles. The origin of most lipids imported into mitochondria is the endoplasmic reticulum, which requires interaction of these two subcellular compartments. Recently, protein complexes that are involved in membrane contact between endoplasmic reticulum and mitochondria were identified, but their role in lipid transport is still unclear. In the present review, we describe components involved in lipid translocation between the endoplasmic reticulum and mitochondria and discuss functional as well as regulatory aspects that are important for lipid homeostasis. PMID:23732475

  19. Lipids as a principle for the identification of Archaebacteria

    NASA Technical Reports Server (NTRS)

    Tornabene, T. G.; Lloyd, R. E.; Holzer, G.; Oro, J.

    1980-01-01

    The 'Archaebacteria' consist of several distinct subgroups including methanogens, extreme halophiles and specific thermoacidophiles. These bacteria are distinct from other bacteria with respect to their characteristic RNA compositions, the absence of muramic acid in the cell walls and the predominance of nonsaponifable lipids. The lipid composition of the Archaebacteria consists of isoprenoid and hydroisoprenoid hydrocarbons and isopranyl glycerol ether lipids. The pathways for the biosynthesis of the lipid components are those shared by most microorganisms and demonstrate a close relationship; however, an independent line of descent is indicated by the formation of the isopranyl glycerol ether lipids. This discontinuity formulates a point for delineating the early stages of biological evolution and for dividing bacteria into two subgroups.

  20. Water Permeability of Asymmetric Planar Lipid Bilayers

    PubMed Central

    Krylov, Andrey V.; Pohl, Peter; Zeidel, Mark L.; Hill, Warren G.

    2001-01-01

    To understand how plasma membranes may limit water flux, we have modeled the apical membrane of MDCK type 1 cells. Previous experiments demonstrated that liposomes designed to mimic the inner and outer leaflet of this membrane exhibited 18-fold lower water permeation for outer leaflet lipids than inner leaflet lipids (Hill, W.G., and M.L. Zeidel. 2000. J. Biol. Chem. 275:30176–30185), confirming that the outer leaflet is the primary barrier to permeation. If leaflets in a bilayer resist permeation independently, the following equation estimates single leaflet permeabilities: 1/PAB = 1/PA + 1/PB (Eq. l), where PAB is the permeability of a bilayer composed of leaflets A and B, PA is the permeability of leaflet A, and PB is the permeability of leaflet B. Using for the MDCK leaflet–specific liposomes gives an estimated value for the osmotic water permeability (Pf) of 4.6 × 10?4 cm/s (at 25°C) that correlated well with experimentally measured values in intact cells. We have now constructed both symmetric and asymmetric planar lipid bilayers that model the MDCK apical membrane. Water permeability across these bilayers was monitored in the immediate membrane vicinity using a Na+-sensitive scanning microelectrode and an osmotic gradient induced by addition of urea. The near-membrane concentration distribution of solute was used to calculate the velocity of water flow (Pohl, P., S.M. Saparov, and Y.N. Antonenko. 1997. Biophys. J. 72:1711–1718). At 36°C, Pf was 3.44 ± 0.35 × 10?3 cm/s for symmetrical inner leaflet membranes and 3.40 ± 0.34 × 10?4 cm/s for symmetrical exofacial membranes. From , the estimated permeability of an asymmetric membrane is 6.2 × 10?4 cm/s. Water permeability measured for the asymmetric planar bilayer was 6.7 ± 0.7 × 10?4 cm/s, which is within 10% of the calculated value. Direct experimental measurement of Pf for an asymmetric planar membrane confirms that leaflets in a bilayer offer independent and additive resistances to water permeation and validates the use of . PMID:11585847

  1. Control of lipid oxidation in extruded salmon jerky snacks.

    PubMed

    Kong, Jian; Perkins, L Brian; Dougherty, Michael P; Camire, Mary Ellen

    2011-01-01

    A shelf-life study was conducted to evaluate the effect of antioxidants on oxidative stability of extruded jerky-style salmon snacks. Deterioration of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) due to lipid oxidation is a major concern for this healthy snack. A control jerky with no added antioxidants and 4 jerkies with antioxidants (rosemary, mixed tocopherols, tertiary butylhydroquinone, and ascorbyl palmitate) added as 0.02% of the lipid content were extruded in duplicate in a Coperion ZSK-25 twin screw extruder. Salmon jerkies from each formulation were placed in 3 mil barrier pouches, flushed with nitrogen, and stored at 35 °C and 75% relative humidity. Lipid oxidation was evaluated as by peroxide value and malonaldehyde content. Other chemical analyses included total fatty acid composition, lipid content, moisture, water activity, pH, and salt. Astaxanthin and CIE L*, a*, b* color were also analyzed at 4-wk intervals. Rosemary inhibited peroxide formation better than did other antioxidants at week 8; no treatment inhibited malonaldehyde levels. All jerkies had lower astaxanthin levels after 8 wk, but rosemary-treated jerky had higher pigment concentrations than did the control at weeks 4 and 8. Protection of omega-3 lipids in these extruded jerkies must be improved to offer consumers a convenient source of these healthful lipids. Practical Application: Salmon flesh can be extruded to produce a jerky that provides 410 mg of omega-3 lipids per serving. Natural antioxidants such as rosemary should be added at levels over 0.02% of the lipid content to help control lipid oxidation. Astaxanthin and CIE a* values correlated well with lipid stability and could be used to monitor quality during storage if initial values are known. PMID:21535658

  2. Deciphering the Unusual Acylation Pattern of Helicobacter pylori Lipid A? †

    PubMed Central

    Stead, Christopher M.; Beasley, Ashley; Cotter, Robert J.; Trent, M. Stephen

    2008-01-01

    The synthesis of “typical” hexa-acylated lipid A occurs via a nine-step enzymatic pathway, which is generally well conserved throughout all gram-negative bacteria. One exception to the rule is Helicobacter pylori, which has only eight homologs to the nine lipid A biosynthetic enzymes. The discrepancy occurs toward the end of the pathway, with H. pylori containing only a single putative secondary acyltransferase encoded by jhp0265. In Escherichia coli K-12, two late acyltransferases, termed LpxL and LpxM, are required for the biosynthesis of hexa-acylated lipid A. Detailed biochemical and genetic analyses reveal that H. pylori Jhp0265 (the protein encoded by jhp0265) is in fact an LpxL homolog, capable of transferring a stearoyl group to the hydroxyl group of the 2? linked fatty acyl chain of lipid A. Despite the lack of a homolog to LpxM in the H. pylori genome, the organism synthesizes a hexa-acylated lipid A species, suggesting that an equivalent enzyme exists. Using radiolabeled lipid A substrates and acyl-acyl carrier protein as the fatty acyl donor, we were able to confirm the presence of a second H. pylori late acyl transferase by biochemical assays. After synthesis of the hexa-acylated lipid A species, several modification enzymes then function to produce the major lipid A species of H. pylori that is tetra-acylated. Jhp0634 was identified as an outer membrane deacylase that removes the 3?-linked acyl chains of H. pylori lipid A. Together, this work elucidates the biochemical machinery required for the acylation and deacylation of the lipid A domain of H. pylori lipopolysaccharide. PMID:18757539

  3. Antimicrobial Peptide-Lipid Binding Interactions and Binding Selectivity

    PubMed Central

    Lad, Mitaben D.; Birembaut, Fabrice; Clifton, Luke A.; Frazier, Richard A.; Webster, John R. P.; Green, Rebecca J.

    2007-01-01

    Surface pressure measurements, external reflection-Fourier transform infrared spectroscopy, and neutron reflectivity have been used to investigate the lipid-binding behavior of three antimicrobial peptides: melittin, magainin II, and cecropin P1. As expected, all three cationic peptides were shown to interact more strongly with the anionic lipid, 1,2 dihexadecanoyl-sn-glycerol-3-(phosphor-rac-(1-glycerol)) (DPPG), compared to the zwitterionic lipid, 1,2 dihexadecanoyl-sn-glycerol-3-phosphocholine (DPPC). All three peptides have been shown to penetrate DPPC lipid layers by surface pressure, and this was confirmed for the melittin-DPPC interaction by neutron reflectivity measurements. Adsorption of peptide was, however, minimal, with a maximum of 0.4 mg m?2 seen for melittin adsorption compared to 2.1 mg m?2 for adsorption to DPPG (from 0.7 ?M solution). The mode of binding to DPPG was shown to depend on the distribution of basic residues within the peptide ?-helix, although in all cases adsorption below the lipid layer was shown to dominate over insertion within the layer. Melittin adsorption to DPPG altered the lipid layer structure observed through changes in the external reflection-Fourier transform infrared lipid spectra and neutron reflectivity. This lipid disruption was not observed for magainin or cecropin. In addition, melittin binding to both lipids was shown to be 50% greater than for either magainin or cecropin. Adsorption to the bare air-water interface was also investigated and surface activity followed the trend melittin>magainin>cecropin. External reflection-Fourier transform infrared amide spectra revealed that melittin adopted a helical structure only in the presence of lipid, whereas magainin and cecropin adopted helical structure also at an air-water interface. This behavior has been related to the different charge distributions on the peptide amino acid sequences. PMID:17325007

  4. Lipid Rafts Prepared by Different Methods Contain Different Connexin Channels, but Gap Junctions Are Not Lipid Rafts

    E-print Network

    Harris, Andrew L.

    plasma membrane lipids will segregate into gel- like liquid-ordered (lo or l )1 and/or fluid liquid are enriched in sphingolipids and cholesterol while remaining segregated from bulk membrane glycerolipids (4 lipid/protein ratio compared with bulk membrane, permits their flotation in and recovery from dis

  5. Lipid Production of Heterotrophic Chlorella sp. from Hydrolysate Mixtures of Lipid-Extracted Microalgal Biomass Residues and Molasses.

    PubMed

    Zheng, Hongli; Ma, Xiaochen; Gao, Zhen; Wan, Yiqin; Min, Min; Zhou, Wenguang; Li, Yun; Liu, Yuhuan; Huang, He; Chen, Paul; Ruan, Roger

    2015-10-01

    This study investigated the feasibility of lipid production of Chlorella sp. from waste materials. Lipid-extracted microalgal biomass residues (LMBRs) and molasses were hydrolyzed, and their hydrolysates were analyzed. Five different hydrolysate mixture ratios (w/w) of LMBRs/molasses (1/0, 1/1, 1/4, 1/9, and 0/1) were used to cultivate Chlorella sp. The results showed that carbohydrate and protein were the two main compounds in the LMBRs, and carbohydrate was the main compound in the molasses. The highest biomass concentration of 5.58 g/L, Y biomass/sugars of 0.59 g/g, lipid productivity of 335 mg/L/day, and Y lipids/sugars of 0.25 g/g were obtained at the hydrolysate mixture ratio of LMBRs/molasses of 1/4. High C/N ratio promoted the conversion of sugars into lipids. The lipids extracted from Chlorella sp. shared similar lipid profile of soybean oil and is therefore a potential viable biodiesel feedstock. These results showed that Chlorella sp. can utilize mixed sugars and amino acids from LMBRs and molasses to accumulate lipids efficiently, thus reducing the cost of microalgal biodiesel production and improving its economic viability. PMID:26234438

  6. Effects of different biomass drying and lipid extraction methods on algal lipid yield, fatty acid profile, and biodiesel quality.

    PubMed

    Hussain, Javid; Liu, Yan; Lopes, Wilson A; Druzian, Janice I; Souza, Carolina O; Carvalho, Gilson C; Nascimento, Iracema A; Liao, Wei

    2015-03-01

    Three lipid extraction methods of hexane Soxhlet (Sox-Hex), Halim (HIP), and Bligh and Dyer (BD) were applied on freeze-dried (FD) and oven-dried (OD) Chlorella vulgaris biomass to evaluate their effects on lipid yield, fatty acid profile, and algal biodiesel quality. Among these three methods, HIP was the preferred one for C. vulgaris lipid recovery considering both extraction efficiency and solvent toxicity. It had the highest lipid yields of 20.0 and 22.0% on FD and OD biomass, respectively, with corresponding neutral lipid yields of 14.8 and 12.7%. The lipid profiling analysis showed that palmitic, oleic, linoleic, and ?-linolenic acids were the major fatty acids in the algal lipids, and there were no significant differences on the amount of these acids between different drying and extraction methods. Correlative models applied to the fatty acid profiles concluded that high contents of palmitic and oleic acids in algal lipids contributed to balancing the ratio of saturated and unsaturated fatty acids and led to a high-quality algal biodiesel. PMID:25588528

  7. Evidence for Lipid/Cholesterol Ordering in Model Lipid Membranes Canay Ege,* Maria K. Ratajczak,y

    E-print Network

    Lee, Ka Yee C.

    Evidence for Lipid/Cholesterol Ordering in Model Lipid Membranes Canay Ege,* Maria K. Ratajczak Copenhagen, Denmark ABSTRACT It has been postulated that for a binary mixture of phospholipid and cholesterol, phospholipid/cholesterol complexes are formed. Using grazing incidence x-ray diffraction, we have obtained

  8. Oxidized lipids and lipid-mediators are involved in cardiovascular injury induced by diesel exhaust particles and ozone

    EPA Science Inventory

    The mechanisms by which air pollutants induce cardiac and vascular injuries are unknown. We hypothesized that these injuries involve alterations in'aortic membrane lipids and lipid-mediators. We exposed male Wistar Kyoto rats (12-15 wk old), nose-only to air, ozone (03; 0.5 ppm),...

  9. Variants identified in a GWAS meta-analysis for blood lipids are associated with the lipid response to fenofibrate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A recent large-scale meta-analysis of genome-wide studies has identified 95 loci, 59 of them novel, as statistically significant predictors of blood lipid traits; we tested whether the same loci explain the observed heterogeneity in response to lipid-lowering therapy with fenofibrate. Using data fro...

  10. LIPID ABNORMALITIES AND LIPID-BASED REPAIR STRATEGIES IN ATOPIC DERMATITIS

    PubMed Central

    Elias, Peter M.

    2013-01-01

    Prior studies have revealed the key roles played by Th1/Th2 cell dysregulation, IgE production, mast cell hyperactivity, and dendritic cell signaling in the evolution of the chronic, pruritic, inflammatory dermatosis that characterizes atopic dermatitis (AD). We review here increasing evidence that the inflammation in AD results primarily from inherited abnormalities in epidermal structural and enzymatic proteins that impact permeability barrier function. We also will show that the barrier defect can be attributed to a paracellular abnormality due to a variety of abnormalities in lipid composition, transport and extracellular organization. Accordingly, we also review the therapeutic implications of this emerging pathogenic paradigm, including several current and potentially novel, lipid-based approaches to corrective therapy. PMID:24128970

  11. Fluorescence Techniques to Study Lipid Dynamics

    PubMed Central

    Sezgin, Erdinc; Schwille, Petra

    2011-01-01

    Biological research has always tremendously benefited from the development of key methodology. In fact, it was the advent of microscopy that shaped our understanding of cells as the fundamental units of life. Microscopic techniques are still central to the elucidation of biological units and processes, but equally important are methods that allow access to the dimension of time, to investigate the dynamics of molecular functions and interactions. Here, fluorescence spectroscopy with its sensitivity to access the single-molecule level, and its large temporal resolution, has been opening up fully new perspectives for cell biology. Here we summarize the key fluorescent techniques used to study cellular dynamics, with the focus on lipid and membrane systems. PMID:21669985

  12. Biocompatible lipidic formulations: phase behavior and microstructure.

    PubMed

    Mele, S; Murgia, S; Caboi, F; Monduzzi, M

    2004-06-22

    Biocompatible systems formulated for use in the food, cosmetic, and pharmaceutical fields are characterized. Ternary phase diagrams of mixtures of natural lipids (glycerol trioleate, glycerol monooleate, diglycerol monooleate, and lecithin) and water were investigated by means of optical microscopy in polarized light and by multinuclear NMR spectroscopy. All systems showed a microemulsion region at high oil content and a large area of coexistence of two liquid crystalline (hexagonal and lamellar) phases. 1H and 13C NMR self-diffusion measurements were used to characterize microstructural features of the microemulsions. On water dilution, the two-phase liquid crystalline region transforms into a creamy emulsion area where the droplets of water are stabilized by both the lamellar and the hexagonal phases, as indicated by 2H NMR measurements. Due to the very effective dispersing action of the two liquid crystalline phases, these emulsions show a high stability toward phase separation. PMID:15986658

  13. Crystallizing Transmembrane Peptides in Lipidic Mesophases

    PubMed Central

    Höfer, Nicole; Aragão, David; Caffrey, Martin

    2010-01-01

    Structure determination of membrane proteins by crystallographic means has been facilitated by crystallization in lipidic mesophases. It has been suggested, however, that this so-called in meso method, as originally implemented, would not apply to small protein targets having ?4 transmembrane crossings. In our study, the hypothesis that the inherent flexibility of the mesophase would enable crystallogenesis of small proteins was tested using a transmembrane pentadecapeptide, linear gramicidin, which produced structure-grade crystals. This result suggests that the in meso method should be considered as a viable means for high-resolution structure determination of integral membrane peptides, many of which are predicted to be coded for in the human genome. PMID:20682243

  14. Lipids of aquatic sediments, recent and ancient

    NASA Technical Reports Server (NTRS)

    Eglinton, G.; Hajibrahim, S. K.; Maxwell, J. R.; Quirke, J. M. E.; Shaw, G. J.; Volkman, J. K.; Wardroper, A. M. K.

    1979-01-01

    Computerized gas chromatography-mass spectrometry (GC-MS) is now an essential tool in the analysis of the complex mixtures of lipids (geolipids) encountered in aquatic sediments, both 'recent' (less than 1 million years old) and ancient. The application of MS, and particularly GC-MS, has been instrumental in the rapid development of organic geochemistry and environmental organic chemistry in recent years. The techniques used have resulted in the identification of numerous compounds of a variety of types in sediments. Most attention has been concentrated on molecules of limited size, mainly below 500 molecular mass, and of limited functionality, for examples, hydrocarbons, fatty acids and alcohols. Examples from recent studies (at Bristol) of contemporary, 'recent' and ancient sediments are presented and discussed.

  15. In vitro performance of lipid-PLGA hybrid nanoparticles as an antigen delivery system: lipid composition matters

    NASA Astrophysics Data System (ADS)

    Hu, Yun; Ehrich, Marion; Fuhrman, Kristel; Zhang, Chenming

    2014-08-01

    Due to the many beneficial properties combined from both poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and liposomes, lipid-PLGA hybrid NPs have been intensively studied as cancer drug delivery systems, bio-imaging agent carriers, as well as antigen delivery vehicles. However, the impact of lipid composition on the performance of lipid-PLGA hybrid NPs as a delivery system has not been well investigated. In this study, the influence of lipid composition on the stability of the hybrid NPs and in vitro antigen release from NPs under different conditions was examined. The uptake of hybrid NPs with various surface charges by dendritic cells (DCs) was carefully studied. The results showed that PLGA NPs enveloped by a lipid shell with more positive surface charges could improve the stability of the hybrid NPs, enable better controlled release of antigens encapsulated in PLGA NPs, as well as enhance uptake of NPs by DC.

  16. In vitro performance of lipid-PLGA hybrid nanoparticles as an antigen delivery system: lipid composition matters.

    PubMed

    Hu, Yun; Ehrich, Marion; Fuhrman, Kristel; Zhang, Chenming

    2014-01-01

    Due to the many beneficial properties combined from both poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) and liposomes, lipid-PLGA hybrid NPs have been intensively studied as cancer drug delivery systems, bio-imaging agent carriers, as well as antigen delivery vehicles. However, the impact of lipid composition on the performance of lipid-PLGA hybrid NPs as a delivery system has not been well investigated. In this study, the influence of lipid composition on the stability of the hybrid NPs and in vitro antigen release from NPs under different conditions was examined. The uptake of hybrid NPs with various surface charges by dendritic cells (DCs) was carefully studied. The results showed that PLGA NPs enveloped by a lipid shell with more positive surface charges could improve the stability of the hybrid NPs, enable better controlled release of antigens encapsulated in PLGA NPs, as well as enhance uptake of NPs by DC. PMID:25232295

  17. In Vivo Linking of Membrane Lipids and the Anion Transporter Band 3 with Thiourea-modified Amphiphilic Lipid Probes

    PubMed Central

    Moriyama, Akihiro; Katagiri, Naohiro; Nishimura, Shinichi; Takahashi, Nobuaki; Kakeya, Hideaki

    2015-01-01

    Membrane proteins interact with membrane lipids for their structural stability and proper function. However, lipid–protein interactions are poorly understood at a molecular level especially in the live cell membrane, due to current limitations in methodology. Here, we report that amphiphilic lipid probes can be used to link membrane lipids and membrane proteins in vivo. Cholesterol and a phospholipid were both conjugated to a fluorescent tag through a linker containing thiourea. In the erythrocyte, the cholesterol probe fluorescently tagged the anion transporter band 3 via thiourea. Tagging by the cholesterol probe, but not by the phospholipid probe, was competitive with an anion transporter inhibitor, implying the presence of a specific binding pocket for cholesterol in this ~100?kDa protein. This method could prove an effective strategy for analyzing lipid–protein interactions in vivo in the live cell membrane. PMID:26616474

  18. In Vivo Linking of Membrane Lipids and the Anion Transporter Band 3 with Thiourea-modified Amphiphilic Lipid Probes.

    PubMed

    Moriyama, Akihiro; Katagiri, Naohiro; Nishimura, Shinichi; Takahashi, Nobuaki; Kakeya, Hideaki

    2015-01-01

    Membrane proteins interact with membrane lipids for their structural stability and proper function. However, lipid-protein interactions are poorly understood at a molecular level especially in the live cell membrane, due to current limitations in methodology. Here, we report that amphiphilic lipid probes can be used to link membrane lipids and membrane proteins in vivo. Cholesterol and a phospholipid were both conjugated to a fluorescent tag through a linker containing thiourea. In the erythrocyte, the cholesterol probe fluorescently tagged the anion transporter band 3 via thiourea. Tagging by the cholesterol probe, but not by the phospholipid probe, was competitive with an anion transporter inhibitor, implying the presence of a specific binding pocket for cholesterol in this ~100?kDa protein. This method could prove an effective strategy for analyzing lipid-protein interactions in vivo in the live cell membrane. PMID:26616474

  19. Renal effects of amphotericin B lipid complex.

    PubMed

    Luke, R G; Boyle, J A

    1998-05-01

    A study was conducted to compare the renal effects of amphotericin B lipid complex (ABLC), a lipid formulation of the widely used antifungal medication, with conventional amphotericin B (AmB) in the treatment of serious fungal infections, including invasive candidiasis, cryptococcal meningitis, and aspergillosis. The clinical experience of ABLC includes two types of open-label studies: randomized comparative (ABLC 5 mg/kg/d compared with AmB 0.6 to 1 mg/kg) and emergency use. In the comparative studies, changes in serum creatinine were evaluated three ways: doubling of the baseline value, an increase from < or = 1.5 mg/dL at baseline to > or = 1.5 mg/dL, and an increase from < or = 1.5 mg/dL at baseline to > or = 2.0 mg/dL. More patients in the AmB group reached these end points than in the ABLC group (P < or = 0.007), and the time needed to reach each of these end points was significantly shorter for the AmB group (P < or = 0.02). Increased serum creatinine was reported as an adverse event more frequently by patients receiving AmB than by patients receiving ABLC. In the emergency use study, a steady and statistically significant decrease in serum creatinine was observed among patients who started ABLC treatment with serum creatinine greater than 2.5 mg/dL due to prior AmB treatment. ABLC offers the physician a valuable, less-nephrotoxic alternative to AmB for the treatment of patients with severe, invasive fungal infections. PMID:9590187

  20. The complexity of prescribing intravenous lipid emulsions.

    PubMed

    Waitzberg, Dan Linetzky; Torrinhas, Raquel Susana

    2015-01-01

    Intravenous lipid emulsions (LEs) are relevant for patients receiving parenteral nutrition because they prevent the depletion of essential fatty acids (FAs) and, as a highly dense energy source, enable the reduction of glucose provision, thereby decreasing the risks of hyperglycemia and hepatic impairment. The prescription of LEs is complex, due mainly to their distinct FA components, which may alter the immune response in different ways and distinctly influence inflammation, oxidative stress and blood coagulation according to their biochemical properties. In addition, an excess of other LE components, such as phospholipids and phytosterols, may be associated with hepatic steatosis and dysfunction. These associations do not represent direct risks or obstacles to LE use in metabolically stable patients but can render the choice of the best LE for hypermetabolic patients difficult. The infusion of LEs according to the available guidelines provides more benefit than harm and should be part of exclusive parenteral nutrition regimens or complement enteral nutrition when appropriate. The patient's metabolic profile should guide the type of FA and amount of lipids that are provided. For critically ill hypermetabolic patients, growing evidence indicates that standard LEs based solely on soybean oil should be avoided in favor of new LEs containing medium-chain triglycerides, olive oil, or fish oil to decrease the provision of potentially oxidative, inflammatory/immunosuppressive, and prothrombotic n-6 FAs. In addition, as sources of eicosapentaenoic and docosahexaenoic acids, LEs containing fish oil may be important for critically ill patients because they allow better modulation of the immune response and likely reduce the length of intensive care unity stay. However, current evidence precludes the recommendation of a specific LE for clinical use in this patient population. PMID:25471811

  1. [Role of membrane lipids in myocardial cytoprotection

    NASA Technical Reports Server (NTRS)

    Grynberg, A.

    2000-01-01

    The cardiomyocyte capacity to regulate ATP production to face any change in energy demand is a major determinant of cardiac function. This process is based on a balanced fatty acid (FA) metabolism, because FA is the main fuel of the heart, although the most expensive one in oxygen. The pathway is, however, weakly controlled by the cardiac myocyte which can well regulate FA mitochondrial entry but not cell FA uptake. For this reason, several pathological situations often result from either harmful accumulation of FA and derivatives or excess FA-oxidation. Control of the FA/glucose balance by decreased energy production from FA would thus offer an alternative strategy in the treatment of ischaemia, providing the cardiomyocytes weak ability in handling the non-metabolised FA is controlled. The initiation and the regulation of cardiac contraction both result from membrane activity; the other major role of lipids in the heart is their contribution to membrane homeostasis through phospholipid synthesis pathways and phospholipases. The anti-anginal activity of Trimetazidine, reported as a cytoprotective effect without a haemo-dynamic component; is associated with reduced use of FA for energy. However, accumulation of FA and derivatives has never been observed. Trimetazidine is reported to increase significantly the synthesis of phospholipids without influencing the other lipid classes, thus increasing the incorporation of FA in membrane structures. This cytoprotection appears to be based on the redirection of the use of FA to phospholipid synthesis, which would decrease their availability for energy production. This class of compounds, with the same properties as Trimetazidine, offers a metabolic approach to the treatment of ischaemia.

  2. Elastic deformation and failure of lipid bilayer membranes containing cholesterol.

    PubMed Central

    Needham, D; Nunn, R S

    1990-01-01

    Giant bilayer vesicles were reconstituted from several lipids and lipid/cholesterol (CHOL) mixtures: stearolyloleoylphosphatidylcholine (SOPC), bovine sphingomyelin (BSM), diarachidonylphosphatidylcholine (DAPC), SOPC/CHOL, BSM/CHOL, DAPC/CHOL, and extracted red blood cell (RBC) lipids with native cholesterol. Single-walled vesicles were manipulated by micropipette suction and several membrane material properties were determined. The properties measured were the elastic area compressibility modulus K, the critical areal strain alpha c, and the tensile strength tau lys, from which the failure energy or membrane toughness Tf was calculated. The elastic area expansion moduli for these lipid and lipid/cholesterol bilayers ranged from 57 dyn/cm for DAPC to 1,734 dyn/cm for BSM/CHOL. The SOPC/CHOL series and RBC lipids had intermediate values. The results indicated that the presence of cholesterol is the single most influential factor in increasing bilayer cohesion, but only for lipids where both chains are saturated, or mono- or diunsaturated. Multiple unsaturation in both lipid chains inhibits the condensing effect of cholesterol in bilayers. The SOPC/CHOL system was studied in more detail. The area expansion modulus showed a nonlinear increase with increasing cholesterol concentration up to a constant plateau, indicating a saturation limit for cholesterol in the bilayer phase of approximately 55 mol% CHOL. The membrane compressibility was modeled by a property-averaging composite theory involving two bilayer components, namely, uncomplexed lipid and a lipid/cholesterol complex of stoichiometry 1/1.22. The area expansion modulus of this molecular composite membrane was evaluated by a combination of the expansion moduli of each component scaled by their area fractions in the bilayer. Bilayer toughness, which is the energy stored in the bilayer at failure, showed a maximum value at approximately 40 mol% CHOL. This breakdown energy was found to be only a fraction of the available thermal energy, implying that many molecules (approximately 50-100) may be involved in forming the defect structure that leads to failure. The area expansion modulus of extracted RBC lipids with native cholesterol was compared with recent measurements of intact RBC membrane compressibility. The natural membrane was also modeled as a simple composite made up to a compressible lipid/cholesterol matrix containing relatively incompressible transmembrane proteins. It appears that the interaction of incompressible proteins with surrounding lipid confers enhanced compressibility on the composite structure. Images FIGURE 1 PMID:2249000

  3. Interactions between lipid bilayers and inorganic material surfaces

    NASA Astrophysics Data System (ADS)

    Mager, Morgan Douglas

    Because of their unique biological and material properties, lipid bilayers have been extensively studied for use in biosensor and drug delivery applications. In the past, these systems have mostly taken the form of bulk solutions. More recently, researchers have integrated bilayers with chip-based architectures to take advantage of advanced optical, scanning probe and electronic characterization. These applications typically involve the creation of hybrid devices with inorganic and bilayer components, both of which affect the final device performance. In particular, the properties of supported lipid bilayers (SLBs) are known to depend on the substrate chemistry and topography as well as the lipid used. In spite of the large body of work involving these systems, there is still much that remains unknown about the formation and ultimate structure of the interface between these very different materials. One outstanding question in the study of SLBs is the role that the bilayer deposition method plays in determining the bilayer properties. In this work, we have developed a new method for forming and patterning lipid bilayers: bubble collapse deposition (BCD). This method is similar to an in situ version of Langmuir-Blodgett deposition, and offers unique possibilities for the fabrication of lipid-based devices. Briefly, a lipid monolayer is "inked" onto the surface of an air bubble. This bubble is then brought down on a solid support and the air is withdrawn. This withdrawal of air shrinks the bubble, which causes the monolayer to fold over on itself and redeposit on the surface as a bilayer. With BCD, we have demonstrated the first SLB formation on alumina using uncharged lipids. Using this system, we have measured a previously unobserved enhanced hydrodynamic coupling at the alumina surface. We have also used BCD to produce a hybrid lipid-gated chemical delivery device with potentially sub-cellular spatial resolution. Because of the unique material properties of the lipid seals in this system, these devices can retain a chemical of interest for weeks and yet rapidly release this load (within tens of ms) when triggered by a simple optical input. Finally, we have used BCD to directly transfer lipids from a cell membrane to a substrate surface. We present studies characterizing which membrane components are transferred, including lipids, proteins and the cytoskeleton. These studies offer both increased functionality of hybrid lipid systems and fundamental insights into the interactions between lipids and common semiconductor fabrication materials.

  4. Lipid Accumulation, Lipid Body Formation, and Acyl Coenzyme A Oxidases of the Yeast Yarrowia lipolytica

    PubMed Central

    Mlí?ková, Kate?ina; Roux, Emeline; Athenstaedt, Karin; d'Andrea, Sabine; Daum, Günther; Chardot, Thierry; Nicaud, Jean-Marc

    2004-01-01

    Yarrowia lipolytica contains five acyl-coenzyme A oxidases (Aox), encoded by the POX1 to POX5 genes, that catalyze the limiting step of peroxisomal ?-oxidation. In this study, we analyzed morphological changes of Y. lipolytica growing in an oleic acid medium and the effect of POX deletions on lipid accumulation. Protrusions involved in the uptake of lipid droplets (LDs) from the medium were seen in electron micrographs of the surfaces of wild-type cells grown on oleic acid. The number of protrusions and surface-bound LDs increased during growth, but the sizes of the LDs decreased. The sizes of intracellular lipid bodies (LBs) and their composition depended on the POX genotype. Only a few, small, intracellular LBs were observed in the mutant expressing only Aox4p (?pox2 ?pox3 ?pox5), but strains expressing either Aox3p or both Aox3p and Aox4p had the same number of LBs as did the wild type. In contrast, strains expressing either Aox2p or both Aox2p and Aox4p formed fewer, but larger, LBs than did the wild type. The size of the LBs increased proportionately with the amount of triacylglycerols in the LBs of the mutants. In summary, Aox2p expression regulates the size of cellular triacylglycerol pools and the size and number of LBs in which these fatty acids accumulate. PMID:15240264

  5. Adipose triglyceride lipase acts on neutrophil lipid droplets to regulate substrate availability for lipid mediator synthesis

    PubMed Central

    Schlager, Stefanie; Goeritzer, Madeleine; Jandl, Katharina; Frei, Robert; Vujic, Nemanja; Kolb, Dagmar; Strohmaier, Heimo; Dorow, Juliane; Eichmann, Thomas O.; Rosenberger, Angelika; Wölfler, Albert; Lass, Achim; Kershaw, Erin E.; Ceglarek, Uta; Dichlberger, Andrea; Heinemann, Akos; Kratky, Dagmar

    2015-01-01

    In humans, mutations in ATGL lead to TG accumulation in LDs of most tissues and cells, including peripheral blood leukocytes. This pathologic condition is called Jordans’ anomaly, in which functional consequences have not been investigated. In the present study, we tested the hypothesis that ATGL plays a role in leukocyte LD metabolism and immune cell function. Similar to humans with loss-of-function mutations in ATGL, we found that global and myeloid-specific Atgl?/? mice exhibit Jordans’ anomaly with increased abundance of intracellular TG-rich LDs in neutrophil granulocytes. In a model of inflammatory peritonitis, lipid accumulation was also observed in monocytes and macrophages but not in eosinophils or lymphocytes. Neutrophils from Atgl?/? mice showed enhanced immune responses in vitro, which were more prominent in cells from global compared with myeloid-specific Atgl?/? mice. Mechanistically, ATGL?/? as well as pharmacological inhibition of ATGL led to an impaired release of lipid mediators from neutrophils. These findings demonstrate that the release of lipid mediators is dependent on the liberation of precursor molecules from the TG-rich pool of LDs by ATGL. Our data provide mechanistic insights into Jordans’ anomaly in neutrophils and suggest that ATGL is a potent regulator of immune cell function and inflammatory diseases. PMID:26109679

  6. Lipid effects on expulsion rate of amphotericin B from solid lipid nanoparticles.

    PubMed

    Tan, See Wei; Billa, Nashiru

    2014-04-01

    We aimed to investigate the effects that natural lipids, theobroma oil (TO) and beeswax (BW), might have on the physical properties of formulated nanoparticles and also the degree of expulsion of encapsulated amphotericin B (AmB) from the nanoparticles during storage. Lecithin and sodium cholate were used as emulsifiers whilst oleic acid (OA) was used to study the influence of the state of orderliness/disorderliness within the matrices of the nanoparticles on the degree of AmB expulsion during storage. BW was found to effect larger z-average diameter compared with TO. Lecithin was found to augment the stability of the nanoparticles imparted by BW and TO during storage. An encapsulation efficiency (%EE) of 59% was recorded when TO was the sole lipid as against 42% from BW. In combination however, the %EE dropped to 39%. When used as sole lipid, TO or BW formed nanoparticles with comparatively higher enthalpies, 21.1 and 23.3 J/g respectively, which subsequently caused significantly higher degree of AmB expulsion, 81 and 83% respectively, whilst only 11.8% was expelled from a binary TO/BW mixture. A tertiary TO/BW/OA mixture registered the lowest enthalpy at 8.07 J/g and expelled 12.6% of AmB but encapsulated only 22% of AmB. In conclusion, nanoparticles made from equal concentrations of TO and BW produced the most desirable properties and worthy of further investigations. PMID:24318197

  7. Proving Lipid Rafts Exist: Membrane Domains in the Prokaryote Borrelia burgdorferi Have the Same Properties as Eukaryotic Lipid Rafts

    PubMed Central

    Chiantia, Salvatore; Toledo, Alvaro; Silvius, John R.; Benach, Jorge L.; London, Erwin

    2013-01-01

    Lipid rafts in eukaryotic cells are sphingolipid and cholesterol-rich, ordered membrane regions that have been postulated to play roles in many membrane functions, including infection. We previously demonstrated the existence of cholesterol-lipid-rich domains in membranes of the prokaryote, B. burgdorferi, the causative agent of Lyme disease [LaRocca et al. (2010) Cell Host & Microbe 8, 331–342]. Here, we show that these prokaryote membrane domains have the hallmarks of eukaryotic lipid rafts, despite lacking sphingolipids. Substitution experiments replacing cholesterol lipids with a set of sterols, ranging from strongly raft-promoting to raft-inhibiting when mixed with eukaryotic sphingolipids, showed that sterols that can support ordered domain formation are both necessary and sufficient for formation of B. burgdorferi membrane domains that can be detected by transmission electron microscopy or in living organisms by Förster resonance energy transfer (FRET). Raft-supporting sterols were also necessary and sufficient for formation of high amounts of detergent resistant membranes from B. burgdorferi. Furthermore, having saturated acyl chains was required for a biotinylated lipid to associate with the cholesterol-lipid-rich domains in B. burgdorferi, another characteristic identical to that of eukaryotic lipid rafts. Sterols supporting ordered domain formation were also necessary and sufficient to maintain B. burgdorferi membrane integrity, and thus critical to the life of the organism. These findings provide compelling evidence for the existence of lipid rafts and show that the same principles of lipid raft formation apply to prokaryotes and eukaryotes despite marked differences in their lipid compositions. PMID:23696733

  8. Insights into thermophilic archaebacterial membrane stability from simplified models of lipid membranes

    NASA Astrophysics Data System (ADS)

    Davis, Charles H.; Nie, Huifen; Dokholyan, Nikolay V.

    2007-05-01

    Lipid aggregation into fluid bilayers is an essential process for sustaining life. Simplified models of lipid structure, which allow for long time scales or large length scales not obtainable with all-atom simulations, have recently been developed and show promise for describing lipid dynamics in biological systems. Here, we describe two simplified models, a reduced-lipid model and a bola-lipid model for thermophilic bacterial membranes, developed for use with the rapid discrete molecular dynamics simulation method. In the reduced-lipid model, we represent the lipid chain by a series of three beads interacting through pairwise discrete potentials that model hydrophobic attractions between hydrocarbon tails in implicit solvent. Our phase diagram recapitulates those produced by continuous potential models with similar coarse-grained lipid representations. We also find that phase transition temperatures for our reduced-lipid model are dependent upon the flexibility of the lipid chain, giving an insight into archaebacterial membrane stability and prompting development of a bola-lipid model specific for archaebacteria lipids. With both the reduced-lipid and bola-lipid model, we find that the reduced flexibility inherent in archaebacteria lipids yields more stable bilayers as manifested by increased phase transition temperatures. The results of these studies provide a simulation methodology for lipid molecules in biological systems and show that discrete molecular dynamics is applicable to lipid aggregation and dynamics.

  9. Mixotrophic continuous flow cultivation of Chlorella protothecoides for lipids.

    PubMed

    Wang, Yanming; Rischer, Heiko; Eriksen, Niels T; Wiebe, Marilyn G

    2013-09-01

    The oleaginous alga Chlorella protothecoides accumulates lipid in its biomass when grown in nitrogen-restricted conditions. To assess the relationship between nitrogen provision and lipid accumulation and to determine the contribution of photosynthesis in mixotrophic growth, C. protothecoides was grown in mixo- and heterotrophic nitrogen-limited continuous flow cultures. Lipid content increased with decreasing C/N, while biomass yield on glucose was not affected. Continuous production of high lipid levels (57% of biomass) was possible at high C/N (87-94). However, the lipid production rate (2.48 g L(-1) d(-1)) was higher at D=0.84 d(-1) with C/N 37 than at D=0.44 d(-1) and C/N 87 even though the lipid content of the biomass was lower (38%). Photosynthesis contributed to biomass and lipid production in mixotrophic conditions, resulting in 13-38% reduction in CO2 production compared with heterotrophic cultures, demonstrating that photo- and heterotrophic growth occurred simultaneously in the same population. PMID:23907064

  10. Paraquat and NADPH-dependent lipid peroxidation in lung microsomes

    SciTech Connect

    Misra, H.P.; Gorsky, L.D.

    1981-10-10

    Since there exists some controversy in the literature as to whether paraquat augments microsomal lipid peroxidation via superoxide anion (O/sub 2//sup -/), the role of paraquat and active oxygen species in NADPH-dependent lung microsomal lipid peroxidation was investigated. Incubation of buffered aerobic mixture of bovine lung microsome and NADPH, in the presence or absence of exogenously added iron, resulted in a progressive formation of lipid peroxides whose accumulation could be followed at 535 nm as malondialdehyde. Paraquat strongly inhibited this lipid peroxidation, Thus, malondialydehyde formation was 50% inhibited by 4 X 10/sup -5/ M paraquat in the reaction mixture. The malondialdehyde color development by lipid peroxides was not affected by this concentration of paraquat. Lipid peroxidation was also strongly inhibited by singlet oxygen scavengers, e.g. dimethylfuran and diphenylfuran, and by catalase. Hydroxyl radical scavengers, e.g. mannitol, benzoate, and ethanol, had little effect in malondialydehyde production. Superoxide dismutase, which removes O/sub 2//sup -/ efficiently, did not inhibit malondialdehyde production by lung microsomes and rather enhanced its formation. A scheme in which paraquat and active O/sub 2/ species may be involved with microsomal lipid peroxidation is presented.

  11. Melittin-induced cholesterol reorganization in lipid bilayer membranes.

    PubMed

    Qian, Shuo; Heller, William T

    2015-10-01

    The peptide melittin, a 26 amino acid, cationic peptide from honey bee (Apis mellifera) venom, disrupts lipid bilayer membranes in a concentration-dependent manner. Rather than interacting with a specific receptor, the peptide interacts directly with the lipid matrix of the membrane in a manner dependent on the lipid composition. Here, a small-angle neutron scattering study of the interaction of melittin with lipid bilayers made of mixtures of dimyristoylphosphatidylcholine (DMPC) and cholesterol (Chol) is presented. Through the use of deuterium-labeled DMPC, changes in the distribution of the lipid and cholesterol in unilamellar vesicles were observed for peptide concentrations below those that cause pores to form. In addition to disrupting the in-plane organization of Chol, melittin produces vesicles having inner and outer leaflet compositions that depend on the lipid-Chol molar ratio and on the peptide concentration. The changes seen at high cholesterol and low peptide concentration are similar to those produced by alamethicin (Qian, S. et al., J. Phys. Chem. B 2014, 118, 11200-11208), which points to an underlying physical mechanism driving the redistribution of Chol, but melittin displays an additional effect not seen with alamethicin. A model for how the peptide drives the redistribution of Chol is proposed. The results suggest that redistribution of the lipids in a target cell membrane by membrane active peptides takes places as a prelude to the lysis of the cell. PMID:26074009

  12. Lipid-mediated muscle insulin resistance: different fat, different pathways?

    PubMed

    Ritter, Olesja; Jelenik, Tomas; Roden, Michael

    2015-08-01

    Increased dietary fat intake and lipolysis result in excessive lipid availability, which relates to impaired insulin sensitivity. Over the last years, several mechanisms possibly underlying lipid-mediated insulin resistance evolved. Lipid intermediates such as diacylglycerols (DAG) associate with changes in insulin sensitivity in many models. DAG activate novel protein kinase C (PKC) isoforms followed by inhibitory serine phosphorylation of insulin receptor substrate 1 (IRS1). Activation of Toll-like receptor 4 (TLR4) raises another lipid class, ceramides (CER), which induce pro-inflammatory pathways and lead to inhibition of Akt phosphorylation. Inhibition of glucosylceramide and ganglioside synthesis results in improved insulin sensitivity and increased activatory tyrosine phosphorylation of IRS1 in the muscle. Incomplete fat oxidation can increase acylcarnitines (ACC), which in turn stimulate pro-inflammatory pathways. This review analyzed the effects of lipid metabolites on insulin action in skeletal muscle of humans and rodents. Despite the evidence for the association of both DAG and CER with insulin resistance, its causal relevance may differ depending on the subcellular localization and the tested cohorts, e.g., athletes. Nevertheless, recent data indicate that individual lipid species and their degree of fatty acid saturation, particularly membrane and cytosolic C18:2 DAG, specifically activate PKC? and induce both acute lipid-induced and chronic insulin resistance in humans. PMID:26108617

  13. Aspirin inhibits formation of cholesterol rafts in fluid lipid membranes.

    PubMed

    Alsop, Richard J; Toppozini, Laura; Marquardt, Drew; Ku?erka, Norbert; Harroun, Thad A; Rheinstädter, Maikel C

    2015-03-01

    Aspirin and other non-steroidal anti-inflammatory drugs have a high affinity for phospholipid membranes, altering their structure and biophysical properties. Aspirin has been shown to partition into the lipid head groups, thereby increasing membrane fluidity. Cholesterol is another well known mediator of membrane fluidity, in turn increasing membrane stiffness. As well, cholesterol is believed to distribute unevenly within lipid membranes leading to the formation of lipid rafts or plaques. In many studies, aspirin has increased positive outcomes for patients with high cholesterol. We are interested if these effects may be, at least partially, the result of a non-specific interaction between aspirin and cholesterol in lipid membranes. We have studied the effect of aspirin on the organization of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) membranes containing cholesterol. Through Langmuir-Blodgett experiments we show that aspirin increases the area per lipid and decreases compressibility at 32.5 mol% cholesterol, leading to a significant increase of fluidity of the membranes. Differential scanning calorimetry provides evidence for the formation of meta-stable structures in the presence of aspirin. The molecular organization of lipids, cholesterol and aspirin was studied using neutron diffraction. While the formation of rafts has been reported in binary DPPC/cholesterol membranes, aspirin was found to locally disrupt membrane organization and lead to the frustration of raft formation. Our results suggest that aspirin is able to directly oppose the formation of cholesterol structures through non-specific interactions with lipid membranes. PMID:25475646

  14. Control of Lipid Accumulation in the Yeast Yarrowia lipolytica?

    PubMed Central

    Beopoulos, Athanasios; Mrozova, Zuzana; Thevenieau, France; Le Dall, Marie-Thérèse; Hapala, Ivan; Papanikolaou, Seraphim; Chardot, Thierry; Nicaud, Jean-Marc

    2008-01-01

    A genomic comparison of Yarrowia lipolytica and Saccharomyces cerevisiae indicates that the metabolism of Y. lipolytica is oriented toward the glycerol pathway. To redirect carbon flux toward lipid synthesis, the GUT2 gene, which codes for the glycerol-3-phosphate dehydrogenase isomer, was deleted in Y. lipolytica in this study. This ?gut2 mutant strain demonstrated a threefold increase in lipid accumulation compared to the wild-type strain. However, mobilization of lipid reserves occurred after the exit from the exponential phase due to ?-oxidation. Y. lipolytica contains six acyl-coenzyme A oxidases (Aox), encoded by the POX1 to POX6 genes, that catalyze the limiting step of peroxisomal ?-oxidation. Additional deletion of the POX1 to POX6 genes in the ?gut2 strain led to a fourfold increase in lipid content. The lipid composition of all of the strains tested demonstrated high proportions of FFA. The size and number of the lipid bodies in these strains were shown to be dependent on the lipid composition and accumulation ratio. PMID:18952867

  15. Curvature Forces in Membrane Lipid-Protein Interactions

    NASA Astrophysics Data System (ADS)

    Brown, Michael F.

    2012-02-01

    Membrane protein conformational changes, folding, and stability may all involve elastic deformation of the bilayer. Non-specific properties of the bilayer play a significant role in modulating protein conformational energetics. A flexible-surface model (FSM) describes the balance of curvature and hydrophobic forces in lipid-protein interactions. The FSM describes elastic coupling of membrane lipids to integral membrane proteins. Curvature and hydrophobic matching to the lipid bilayer entails a stress field that explains membrane protein stability. Rhodopsin provides an important example, where solid-state NMR and FTIR spectroscopy characterize the energy landscape of the dynamically activated receptor. Time-resolved UV-visible and FTIR spectroscopic studies show how membrane lipids affect the metarhodopsin equilibrium due to non-specific material properties. Influences of bilayer thickness, nonlamellar-forming lipids, detergents, and osmotic stress on rhodopsin function are all explained by the new biomembrane model. By contrast, the older fluid-mosaic model fails to account for such effects on membrane protein activity. According to the FSM proteins are regulated by membrane lipids whose spontaneous curvature most closely matches the activated state within the lipid membrane.

  16. Lipid mediator profile in vernix caseosa reflects skin barrier development.

    PubMed

    Checa, Antonio; Holm, Tina; Sjödin, Marcus O D; Reinke, Stacey N; Alm, Johan; Scheynius, Annika; Wheelock, Craig E

    2015-01-01

    Vernix caseosa (VC) is a protective layer that covers the skin of most human newborns. This study characterized the VC lipid mediator profile, and examined its relationship to gestational period, gender of the newborn and maternal lifestyle. VC collected at birth from 156 newborns within the ALADDIN birth cohort was analyzed and 3 different groups of lipid mediators (eicosanoids and related oxylipin analogs, endocannabinoids and sphingolipids) were screened using LC-MS/MS. A total of 54 compounds were detected in VC. A number of associations between lipid mediators and the gestational period were observed, including increases in the ceramide to sphingomyelin ratio as well as the endocannabinoids anandamide and 2-arachidonoylglycerol. Gender-specific differences in lipid mediator levels were observed for all 3 lipid classes. In addition, levels of the linoleic acid oxidation products 9(10)-epoxy-12Z-octadecenoic and 12(13)-epoxy-9Z-octadecenoic acid (EpOMEs) as well as 12,13-dihydroxy-9Z-octadecenoic acid (DiHOME) were increased in VC of children from mothers with an anthroposophic lifestyle. Accordingly, VC was found to be rich in multiple classes of bioactive lipid mediators, which evidence lifestyle, gender and gestational week dependencies. Levels of lipid mediators in VC may therefore be useful as early stage non-invasive markers of the development of the skin as a protective barrier. PMID:26521946

  17. Lipid mediator profile in vernix caseosa reflects skin barrier development

    PubMed Central

    Checa, Antonio; Holm, Tina; Sjödin, Marcus O. D.; Reinke, Stacey N.; Alm, Johan; Scheynius, Annika; Wheelock, Craig E.

    2015-01-01

    Vernix caseosa (VC) is a protective layer that covers the skin of most human newborns. This study characterized the VC lipid mediator profile, and examined its relationship to gestational period, gender of the newborn and maternal lifestyle. VC collected at birth from 156 newborns within the ALADDIN birth cohort was analyzed and 3 different groups of lipid mediators (eicosanoids and related oxylipin analogs, endocannabinoids and sphingolipids) were screened using LC-MS/MS. A total of 54 compounds were detected in VC. A number of associations between lipid mediators and the gestational period were observed, including increases in the ceramide to sphingomyelin ratio as well as the endocannabinoids anandamide and 2-arachidonoylglycerol. Gender-specific differences in lipid mediator levels were observed for all 3 lipid classes. In addition, levels of the linoleic acid oxidation products 9(10)-epoxy-12Z-octadecenoic and 12(13)-epoxy-9Z-octadecenoic acid (EpOMEs) as well as 12,13-dihydroxy-9Z-octadecenoic acid (DiHOME) were increased in VC of children from mothers with an anthroposophic lifestyle. Accordingly, VC was found to be rich in multiple classes of bioactive lipid mediators, which evidence lifestyle, gender and gestational week dependencies. Levels of lipid mediators in VC may therefore be useful as early stage non-invasive markers of the development of the skin as a protective barrier. PMID:26521946

  18. Lipid partitioning at the nuclear envelope controls membrane biogenesis.

    PubMed

    Barbosa, Antonio Daniel; Sembongi, Hiroshi; Su, Wen-Min; Abreu, Susana; Reggiori, Fulvio; Carman, George M; Siniossoglou, Symeon

    2015-10-15

    Partitioning of lipid precursors between membranes and storage is crucial for cell growth, and its disruption underlies pathologies such as cancer, obesity, and type 2 diabetes. However, the mechanisms and signals that regulate this process are largely unknown. In yeast, lipid precursors are mainly used for phospholipid synthesis in nutrient-rich conditions in order to sustain rapid proliferation but are redirected to triacylglycerol (TAG) stored in lipid droplets during starvation. Here we investigate how cells reprogram lipid metabolism in the endoplasmic reticulum. We show that the conserved phosphatidate (PA) phosphatase Pah1, which generates diacylglycerol from PA, targets a nuclear membrane subdomain that is in contact with growing lipid droplets and mediates TAG synthesis. We find that cytosol acidification activates the master regulator of Pah1, the Nem1-Spo7 complex, thus linking Pah1 activity to cellular metabolic status. In the absence of TAG storage capacity, Pah1 still binds the nuclear membrane, but lipid precursors are redirected toward phospholipids, resulting in nuclear deformation and a proliferation of endoplasmic reticulum membrane. We propose that, in response to growth signals, activation of Pah1 at the nuclear envelope acts as a switch to control the balance between membrane biogenesis and lipid storage. PMID:26269581

  19. Steady-state compartmentalization of lipid membranes by active proteins.

    PubMed Central

    Sabra, M C; Mouritsen, O G

    1998-01-01

    Using a simple microscopic model of lipid-protein interactions, based on the hydrophobic matching principle, we study some generic aspects of lipid-membrane compartmentalization controlled by a dispersion of active integral membrane proteins. The activity of the proteins is simulated by conformational excitations governed by an external drive, and the deexcitation is controlled by interaction of the protein with its lipid surroundings. In response to the flux of energy into the proteins from the environment and the subsequent dissipation of energy into the lipid bilayer, the lipid-protein assembly reorganizes into a steady-state structure with a typical length scale determined by the strength of the external drive. In the specific case of a mixed dimyristoylphosphatidylcholine-distearoylphosphatidylcholine bilayer in the gel-fluid coexistence region, it is shown explicitly by computer simulation that the activity of an integral membrane protein can lead to a compartmentalization of the lipid-bilayer membrane. The compartmentalization is related to the dynamical process of phase separation and lipid domain formation. PMID:9533687

  20. Lipid partitioning at the nuclear envelope controls membrane biogenesis

    PubMed Central

    Barbosa, Antonio Daniel; Sembongi, Hiroshi; Su, Wen-Min; Abreu, Susana; Reggiori, Fulvio; Carman, George M.; Siniossoglou, Symeon

    2015-01-01

    Partitioning of lipid precursors between membranes and storage is crucial for cell growth, and its disruption underlies pathologies such as cancer, obesity, and type 2 diabetes. However, the mechanisms and signals that regulate this process are largely unknown. In yeast, lipid precursors are mainly used for phospholipid synthesis in nutrient-rich conditions in order to sustain rapid proliferation but are redirected to triacylglycerol (TAG) stored in lipid droplets during starvation. Here we investigate how cells reprogram lipid metabolism in the endoplasmic reticulum. We show that the conserved phosphatidate (PA) phosphatase Pah1, which generates diacylglycerol from PA, targets a nuclear membrane subdomain that is in contact with growing lipid droplets and mediates TAG synthesis. We find that cytosol acidification activates the master regulator of Pah1, the Nem1-Spo7 complex, thus linking Pah1 activity to cellular metabolic status. In the absence of TAG storage capacity, Pah1 still binds the nuclear membrane, but lipid precursors are redirected toward phospholipids, resulting in nuclear deformation and a proliferation of endoplasmic reticulum membrane. We propose that, in response to growth signals, activation of Pah1 at the nuclear envelope acts as a switch to control the balance between membrane biogenesis and lipid storage. PMID:26269581

  1. Phase segregation of polymerizable lipids to construct filters for separating lipid-membrane-embedded species

    PubMed Central

    Hu, Shu-Kai; Chen, Ya-Ming; Chao, Ling

    2014-01-01

    Supported lipid bilayer (SLB) platforms have been developed to transport and separate membrane-embedded species in the species' native bilayer environment. In this study, we used the phase segregation phenomenon of lipid mixtures containing a polymerizable diacetylene phospholipid, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DiynePC), and a nonpolymerizable phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), to create filter barrier structures in SLBs. Upon exposing the phase segregated samples to UV light, the DiynePC-rich domains could become crosslinked and remain fixed on the surface of the support, while the DOPC-rich regions, where no crosslinking could happen, could be removed later by detergent washing, and thus became the void regions in the filter. During the filter fabrication process, we used the laminar flow configuration in a microfluidic channel to control the spatial locations of the feed region and filter region in the SLB. The flow in a microfluidic channel was also used to apply a strong hydrodynamic shear stress to the SLB to transport the membrane-embedded species from the feed region to the filter region. We varied the DiynePC/DOPC molar ratio from 60/40 to 80/20 to adjust the cutoff size of the filter barriers and used two model membrane-embedded species of different sizes to examine the filtering capability. One of the model species, Texas Red 1,2-dihexa-decanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (Texas Red DHPE), had a single-lipid size, and the other species, cholera toxin subunit B-GM1 complex, had a multilipid size. When the DiynePC/DOPC molar ratio was 60/40, both species had high penetration ratios in the filter region. However, when the ratio was increased to 70/30, only the Texas Red DHPE, which was the smaller of the two model species, could penetrate the filter to a considerable extent. When the ratio was increased to 80/20, neither of the model species could penetrate the filter region. The results showed the possibility of using phase segregation of a mixture containing a polymerizable lipid and a nonpolymerizable lipid to fabricate filter barrier structures with tunable cutoff sizes in SLBs. PMID:25332729

  2. Phase segregation of polymerizable lipids to construct filters for separating lipid-membrane-embedded species.

    PubMed

    Hu, Shu-Kai; Chen, Ya-Ming; Chao, Ling

    2014-09-01

    Supported lipid bilayer (SLB) platforms have been developed to transport and separate membrane-embedded species in the species' native bilayer environment. In this study, we used the phase segregation phenomenon of lipid mixtures containing a polymerizable diacetylene phospholipid, 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (DiynePC), and a nonpolymerizable phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), to create filter barrier structures in SLBs. Upon exposing the phase segregated samples to UV light, the DiynePC-rich domains could become crosslinked and remain fixed on the surface of the support, while the DOPC-rich regions, where no crosslinking could happen, could be removed later by detergent washing, and thus became the void regions in the filter. During the filter fabrication process, we used the laminar flow configuration in a microfluidic channel to control the spatial locations of the feed region and filter region in the SLB. The flow in a microfluidic channel was also used to apply a strong hydrodynamic shear stress to the SLB to transport the membrane-embedded species from the feed region to the filter region. We varied the DiynePC/DOPC molar ratio from 60/40 to 80/20 to adjust the cutoff size of the filter barriers and used two model membrane-embedded species of different sizes to examine the filtering capability. One of the model species, Texas Red 1,2-dihexa-decanoyl-sn-glycero-3-phosphoethanolamine triethylammonium salt (Texas Red DHPE), had a single-lipid size, and the other species, cholera toxin subunit B-GM1 complex, had a multilipid size. When the DiynePC/DOPC molar ratio was 60/40, both species had high penetration ratios in the filter region. However, when the ratio was increased to 70/30, only the Texas Red DHPE, which was the smaller of the two model species, could penetrate the filter to a considerable extent. When the ratio was increased to 80/20, neither of the model species could penetrate the filter region. The results showed the possibility of using phase segregation of a mixture containing a polymerizable lipid and a nonpolymerizable lipid to fabricate filter barrier structures with tunable cutoff sizes in SLBs. PMID:25332729

  3. Influence of encapsulated functional lipids on crystal structure and chemical stability in solid lipid nanoparticles: Towards bioactive-based design of delivery systems.

    PubMed

    Salminen, Hanna; Gömmel, Christina; Leuenberger, Bruno H; Weiss, Jochen

    2016-01-01

    We investigated the influence of physicochemical properties of encapsulated functional lipids--vitamin A, ?-carotene and ?-3 fish oil--on the structural arrangement of solid lipid nanoparticles (SLN). The relationship between the crystal structure and chemical stability of the incorporated bioactive lipids was evaluated with different emulsifier compositions of a saponin-rich, food-grade Quillaja extract alone or combined with high-melting or low-melting lecithins. The major factors influencing the structural arrangement and chemical stability of functional lipids in solid lipid dispersions were their solubility in the aqueous phase and their crystallization temperature in relation to that of the carrier lipid. The results showed that the stabilization of the ?-subcell crystals in the lattice of the carrier lipid is a key parameter for forming stable solid lipid dispersions. This study contributes to a better understanding of SLN as a function of the bioactive lipid. PMID:26213058

  4. Short chain ladderanes: Oxic biodegradation products of anammox lipids

    NASA Astrophysics Data System (ADS)

    Rush, Darci; Jaeschke, Andrea; Hopmans, Ellen C.; Geenevasen, Jan A. J.; Schouten, Stefan; Damsté, Jaap S. Sinninghe

    2011-03-01

    Anammox, the microbial anaerobic oxidation of ammonium by nitrite to produce dinitrogen gas, has been recognized as a key process in both the marine and freshwater nitrogen cycles, and found to be a major sink for fixed inorganic nitrogen in the oceans. Ladderane lipids are unique anammox bacterial membrane lipids that have been used as biomarkers for anammox bacteria in recent and past environmental settings. However, the fate of ladderane lipids during diagenesis is as of yet unknown. In this study, we performed oxic degradation experiments (at 20-100 °C) with anammox bacterial biomass to simulate early diagenetic processes occurring in the water column and at the sediment-water interface. Abundances of C 18 and C 20 ladderane lipids decreased with increasing temperatures, testifying to their labile nature. The most abundant products formed were ladderane lipids with a shorter alkyl side chain (C 14 and C 16 ladderane fatty acids), which was unambiguously established using two-dimensional NMR techniques on an isolated C 14-[3]-ladderane fatty acid. The most pronounced production of these short-chain lipids was at 40 °C, suggesting that degradation of ladderane lipids was microbially mediated, likely through a ?-oxidation pathway. An HPLC-MS/MS method was developed for the detection of these ladderane alteration products in environmental samples and positively tested on various sediments. This showed that the ladderanes formed during degradation experiments also naturally occur in the marine environment. Thus, short-chain ladderane lipids may complement the original longer-chain ladderane lipids as suitable biomarkers for the detection of anammox processes in past depositional environments.

  5. Lipid Emulsion in Treatment of Local Anesthetic Toxicity.

    PubMed

    Collins, Shawn; Neubrander, Judy; Vorst, Zachary; Sheffield, Brad

    2015-08-01

    Epidural, spinal, regional, local, and intravenous administration of local anesthetics (LAs) is a cornerstone of anesthetic practice. LA toxicity is a grave consequence that is of great significance to anesthesia providers. Outcomes of LA toxicity range from inconvenient symptoms such as tinnitus, twitching, and hypotension to seizures; cardiovascular or respiratory collapse; and death. Lipid emulsion has emerged as a potential "magic bullet" in treating LA toxicity. This literature review provides background information and proposed mechanisms of action for LAs and lipid emulsion as well as animal experiments and a case report that speak to the effectiveness of lipid emulsion in the face of LA toxicity. PMID:26210562

  6. Hepatitis C Virus Life Cycle and Lipid Metabolism

    PubMed Central

    Popescu, Costin-Ioan; Riva, Laura; Vlaicu, Ovidiu; Farhat, Rayan; Rouillé, Yves; Dubuisson, Jean

    2014-01-01

    Hepatitis C Virus (HCV) infects over 150 million people worldwide. In most cases HCV infection becomes chronic, causing liver disease ranging from fibrosis to cirrhosis and hepatocellular carcinoma. HCV affects the cholesterol homeostasis and at the molecular level, every step of the virus life cycle is intimately connected to lipid metabolism. In this review, we present an update on the lipids and apolipoproteins that are involved in the HCV infectious cycle steps: entry, replication and assembly. Moreover, the result of the assembly process is a lipoviroparticle, which represents a peculiarity of hepatitis C virion. This review illustrates an example of an intricate virus-host interaction governed by lipid metabolism. PMID:25517881

  7. Unusual lipid structures selectively reduce the toxicity of amphotericin B

    SciTech Connect

    Janoff, A.S.; Boni, L.T.; Popescu, M.C.; Minchey, S.R.; Cullis, P.R.; Madden, T.D.; Taraschi, T.; Gruner, S.M.; Shyamsunder, E.; Tate, M.W.; Mendelsohn, R.; Bonner, D. )

    1988-08-01

    Ribbon-like structures result when amphotericin B interacts with lipid in an aqueous environment. At high ratios of amphotericin to lipid these structures, which are lipid-stabilized amphotericin aggregates, become prevalent resulting in a dramatic attenuation of amphotericin-mediated mammalian cell, but not fungal cell, toxicity. Studies utilizing freeze-etch electron microscopy, differential scanning calorimetry, {sup 31}P NMR, x-ray diffraction, and optical spectroscopy revealed that this toxicity attenuation is related to the macromolecular structure of the complexes in a definable fashion. It is likely that amphotericin in this specific form will have a much improved therapeutic utility.

  8. Characterization of the transverse relaxation rates in lipid bilayers

    SciTech Connect

    Watnick, P.I.; Dea, P.; Chan, S.I. )

    1990-03-01

    The 2H NMR transverse relaxation rates of a deuterated phospholipid bilayer reflect slow motions in the bilayer membrane. A study of dimyristoyl lecithin specifically deuterated at several positions of the hydrocarbon chains indicates that these motions are cooperative and are confined to the hydrocarbon chains of the lipid bilayer. However, lipid head group interactions do play an important role in modulating the properties of the cooperative fluctuations of the hydrocarbon chains (director fluctuations), as evidenced by the effects of various lipid additives on the 2H NMR transverse relaxation rates of the dimyristoyl lecithin bilayer.

  9. Peroxisomes: a Nexus for Lipid Metabolism and Cellular Signaling

    PubMed Central

    Lodhi, Irfan J.; Semenkovich, Clay F.

    2014-01-01

    Peroxisomes are often dismissed as the cellular hoi polloi, relegated to cleaning up reactive oxygen chemical debris discarded by other organelles. However, their functions extend far beyond hydrogen peroxide metabolism. Peroxisomes are intimately associated with lipid droplets and mitochondria, and their ability to carry out fatty acid oxidation and lipid synthesis, especially the production of ether lipids, may be critical for generating cellular signals required for normal physiology. Here we review the biology of peroxisomes and their potential relevance to human disorders including cancer, obesity-related diabetes, and degenerative neurologic disease. PMID:24508507

  10. Activation of lipid peroxidation: a mechanism triggering the autoimmune response.

    PubMed

    Prilipko, L L; Savov, V M; Kagan, V E

    1983-01-01

    Emotional-pain stress leads to accumulation of lipid peroxidation products in rat brain tissues and to an increase in the number of antibrain antibodies against water-soluble and membrane-bound antigens in rat blood. An injection of the free radical scavenger, 4-methyl-2.6-di-tert-butylphenol to experimental animals eliminates the accumulation of lipid peroxidation products "in vivo" and completely prevents the appearance of antibrain antibodies. The activation of lipid peroxidation under stress may be regarded as a possible cause of the brain-specific antibodies release into the blood flow. PMID:6687140

  11. Simulation of hydrogen bonding and hydration in pure lipid bilayers

    NASA Astrophysics Data System (ADS)

    Tobochnik, Jan; Zuckermann, Martin J.; Zhang, Zhengping

    1995-06-01

    We propose a model for phase transitions involving hydrogen bonding in lipid bilayers. The model combines a five-state interacting hydrogen bonding model of the polar heads on a rectangular lattice with a ten-state model of the hydrocarbon chain states on a triangular lattice. Experimental data for the transition temperatures for the lipids dimyristoylphosphatidylcholine (DMPC) and dimyristoyl phosphatidylethanolamine (DMPE) are used to determine phenomenological parameters needed in Monte Carlo simulations of the lipid bilayers. The latent heats for the chain melting transitions of DMPC and DMPE are then computed in the simulations and compared with experiment.

  12. Carbon nanotubes for stabilization of nanostructured lipid particles

    NASA Astrophysics Data System (ADS)

    Gaunt, Nicholas P.; Patil-Sen, Yogita; Baker, Matthew J.; Kulkarni, Chandrashekhar V.

    2014-12-01

    Carbon nanotubes (CNTs) are increasingly studied for innovative biotechnological applications particularly where they are combined with essential biological materials like lipids. Lipids have been used earlier for enhancing the dispersibility of CNTs in aqueous solutions. Here we report a novel application of CNTs for stabilization of internally self-assembled nanostructured lipid particles of 2-5 ?m size. Single-walled (pristine) as well as -OH and -COOH functionalized multi-walled CNTs were employed to produce nanostructured emulsions which stayed stable for months and could be re-dispersed after complete dehydration. Concentrations of CNTs employed for stabilization were very low; moreover CNTs were well-decorated with lipid molecules. These features contribute towards reducing their toxicity and improving biocompatibility for biomedical and pharmaceutical applications. Our approach paves the way for future development of combination therapies employing both CNTs and nanostructured lipid self-assembly together as carriers of different drugs.Carbon nanotubes (CNTs) are increasingly studied for innovative biotechnological applications particularly where they are combined with essential biological materials like lipids. Lipids have been used earlier for enhancing the dispersibility of CNTs in aqueous solutions. Here we report a novel application of CNTs for stabilization of internally self-assembled nanostructured lipid particles of 2-5 ?m size. Single-walled (pristine) as well as -OH and -COOH functionalized multi-walled CNTs were employed to produce nanostructured emulsions which stayed stable for months and could be re-dispersed after complete dehydration. Concentrations of CNTs employed for stabilization were very low; moreover CNTs were well-decorated with lipid molecules. These features contribute towards reducing their toxicity and improving biocompatibility for biomedical and pharmaceutical applications. Our approach paves the way for future development of combination therapies employing both CNTs and nanostructured lipid self-assembly together as carriers of different drugs. Electronic supplementary information (ESI) available: Concentration series studies with Raman spectroscopy and small angle X-ray diffraction pattern for dry lipid and dehydrated CNT-lipid particles support the article. See DOI: 10.1039/c4nr05593d

  13. Lipid extraction from microalgae using a single ionic liquid

    DOEpatents

    Salvo, Roberto Di; Reich, Alton; Dykes, Jr., H. Waite H.; Teixeira, Rodrigo

    2013-05-28

    A one-step process for the lysis of microalgae cell walls and separation of the cellular lipids for use in biofuel production by utilizing a hydrophilic ionic liquid, 1-butyl-3-methylimidazolium. The hydrophilic ionic liquid both lyses the microalgae cell walls and forms two immiscible layers, one of which consists of the lipid contents of the lysed cells. After mixture of the hydrophilic ionic liquid with a suspension of microalgae cells, gravity causes a hydrophobic lipid phase to move to a top phase where it is removed from the mixture and purified. The hydrophilic ionic liquid is recycled to lyse new microalgae suspensions.

  14. Lactobacillus rhamnosus lowers zebrafish lipid content by changing gut microbiota and host transcription of genes involved in lipid metabolism

    PubMed Central

    Falcinelli, Silvia; Picchietti, Simona; Rodiles, Ana; Cossignani, Lina; Merrifield, Daniel L.; Taddei, Anna Rita; Maradonna, Francesca; Olivotto, Ike; Gioacchini, Giorgia; Carnevali, Oliana

    2015-01-01

    The microbiome plays an important role in lipid metabolism but how the introduction of probiotic communities affects host lipid metabolism is poorly understood. Using a multidisciplinary approach we addressed this knowledge gap using the zebrafish model by coupling high-throughput sequencing with biochemical, molecular and morphological analysis to evaluate the changes in the intestine. Analysis of bacterial 16S libraries revealed that Lactobacillus rhamnosus was able to modulate the gut microbiome of zebrafish larvae, elevating the abundance of Firmicutes sequences and reducing the abundance of Actinobacteria. The gut microbiome changes modulated host lipid processing by inducing transcriptional down-regulation of genes involved in cholesterol and triglycerides metabolism (fit2, agpat4, dgat2, mgll, hnf4?, scap, and cck) concomitantly decreasing total body cholesterol and triglyceride content and increasing fatty acid levels. L. rhamnosus treatment also increased microvilli and enterocyte lengths and decreased lipid droplet size in the intestinal epithelium. These changes resulted in elevated zebrafish larval growth. This integrated system investigation demonstrates probiotic modulation of the gut microbiome, highlights a novel gene network involved in lipid metabolism, provides an insight into how the microbiome regulates molecules involved in lipid metabolism, and reveals a new potential role for L. rhamnosus in the treatment of lipid disorders. PMID:25822072

  15. Lactobacillus rhamnosus lowers zebrafish lipid content by changing gut microbiota and host transcription of genes involved in lipid metabolism.

    PubMed

    Falcinelli, Silvia; Picchietti, Simona; Rodiles, Ana; Cossignani, Lina; Merrifield, Daniel L; Taddei, Anna Rita; Maradonna, Francesca; Olivotto, Ike; Gioacchini, Giorgia; Carnevali, Oliana

    2015-01-01

    The microbiome plays an important role in lipid metabolism but how the introduction of probiotic communities affects host lipid metabolism is poorly understood. Using a multidisciplinary approach we addressed this knowledge gap using the zebrafish model by coupling high-throughput sequencing with biochemical, molecular and morphological analysis to evaluate the changes in the intestine. Analysis of bacterial 16S libraries revealed that Lactobacillus rhamnosus was able to modulate the gut microbiome of zebrafish larvae, elevating the abundance of Firmicutes sequences and reducing the abundance of Actinobacteria. The gut microbiome changes modulated host lipid processing by inducing transcriptional down-regulation of genes involved in cholesterol and triglycerides metabolism (fit2, agpat4, dgat2, mgll, hnf4?, scap, and cck) concomitantly decreasing total body cholesterol and triglyceride content and increasing fatty acid levels. L. rhamnosus treatment also increased microvilli and enterocyte lengths and decreased lipid droplet size in the intestinal epithelium. These changes resulted in elevated zebrafish larval growth. This integrated system investigation demonstrates probiotic modulation of the gut microbiome, highlights a novel gene network involved in lipid metabolism, provides an insight into how the microbiome regulates molecules involved in lipid metabolism, and reveals a new potential role for L. rhamnosus in the treatment of lipid disorders. PMID:25822072

  16. Altered lipid composition and enhanced lipid production in green microalga by introduction of brassica diacylglycerol acyltransferase 2

    PubMed Central

    Ahmad, Irshad; Sharma, Anil K.; Daniell, Henry; Kumar, Shashi

    2015-01-01

    Summary Higher lipid biosynthesis and accumulation are important to achieve economic viability of biofuel production via microalgae. To enhance lipid content, Chlamydomonas reinhardtii was genetically engineered with a key enzyme diacylglycerol acyltransferase (BnDGAT2) from Brassica napus, responsible for neutral lipid biosynthesis. The transformed colonies harbouring aph7 gene, screened on hygromycin-supplemented medium, achieved transformation frequency of ~120 ± 10 colonies/1 × 106 cells. Transgene integration and expression were confirmed by PCR, Southern blots, staining lipid droplets, proteins and spectro-fluorometric analysis of Nile red-stained cells. The neutral lipid is a major class (over 80% of total lipids) and most significant requirement for biodiesel production; this was remarkably higher in the transformed alga than the untransformed control. The levels of saturated fatty acids in the transformed alga decreased to about 7% while unsaturated fatty acids increased proportionately when compared to wild type cells. Polyunsaturated fatty acids, especially ?-linolenic acid, an essential omega-3 fatty acid, were enhanced up to 12% in the transformed line. Nile red staining confirmed formation of a large number of lipid globules in the transformed alga. Evaluation of long-term stability and vitality of the transgenic alga revealed that cryopreservation produced significantly higher quantity of lipid than those maintained continuously over 128 generations on solid medium. The overexpression of BnDGAT2 significantly altered the fatty acids profile in the transformed alga. Results of this study offer a valuable strategy of genetic manipulation for enhancing polyunsaturated fatty acids and neutral lipids for biofuel production in algae. PMID:25403771

  17. Lignes directrices simplifiées sur les lipides

    PubMed Central

    Allan, G. Michael; Lindblad, Adrienne J.; Comeau, Ann; Coppola, John; Hudson, Brianne; Mannarino, Marco; McMinis, Cindy; Padwal, Raj; Schelstraete, Christine; Zarnke, Kelly; Garrison, Scott; Cotton, Candra; Korownyk, Christina; McCormack, James; Nickel, Sharon; Kolber, Michael R.

    2015-01-01

    Résumé Objectif Produire un guide de pratique clinique comportant une approche simplifiée à la prévention primaire des maladies cardiovasculaires (MCV), en insistant sur l’estimation du risque de MCV et la prise en charge des profils lipidiques à l’intention des cliniciens de soins primaires et leurs équipes; nous avons recherché la contribution de professionnels des soins primaires qui n’avaient que peu ou pas de conflits d’intérêts et nous nous sommes concentrés sur les données probantes de la plus haute qualité accessibles. Méthodes Neuf professionnels de la santé (4 médecins de famille, 2 internistes, 1 infirmière praticienne, 1 infirmière autorisée et 1 pharmacienne) et 1 membre non votant (pharmacienne gestionnaire de projet) formaient le comité principal appelé le Lipid Pathway Committee (le comité). La sélection des membres s’est fondée sur la profession, le milieu de pratique et son emplacement. Les membres ont divulgué tous leurs conflits d’intérêts potentiels ou réels. Le processus d’élaboration des lignes directrices était itératif et s’appuyait sur des affichages en ligne, une révision détaillée des données probantes, des réunions par téléphone et en ligne. Le comité a cerné 12 questions prioritaires à répondre. Le groupe de révision des données probantes a répondu à ces questions. À la suite d’un examen des réponses, les principales recommandations ont été formulées par consensus du comité. Nous avons produit une ébauche des lignes directrices qui a ensuite été peaufinée, distribuée à un groupe de cliniciens (médecins de famille, autres spécialistes, pharmaciens, infirmières et infirmières praticiennes) et à des patients pour obtenir de la rétroaction, la réviser en conséquence et le comité l’a ensuite finalisée. Recommandations Des recommandations sont présentées concernant le dépistage et les analyses, les évaluations du risque, le suivi, de même que le rôle de l’acide acétylsalicylique en prévention primaire. Conclusion Ces lignes directrices simplifiées sur les lipides offrent des recommandations pratiques pour la prévention et le traitement des MCV à l’intention des professionnels des soins primaires. Toutes les recommandations ont pour but d’aider à la prise de décision conjointement avec les patients plutôt que de la dicter.

  18. Identification of a new class of lipid droplet-associated proteins in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lipid droplets in plants (also known as oil bodies, lipid bodies or oleosomes) are well characterized in seeds, and oleosins, the major proteins associated with their surface, were shown to be important for stabilizing lipid droplets during seed desiccation and rehydration. However, lipid droplets ...

  19. Phase-separation transitions in asymmetric lipid bilayers

    E-print Network

    Shunsuke F. Shimobayashi; Masatoshi Ichikawa; Takashi Taniguchi

    2015-04-13

    Morphological transitions of phase separation associated with the asymmetry of lipid composition were investigated using micrometer-sized vesicles of lipid bilayers made from a lipid mixture. The complete macro-phase-separated morphology undergoes a transition to a micro-phase-separation-like morphology via a lorate morphology as a metastable state. The transition leads to the emergence of monodisperse nanosized domains through repeated domain scission events. Moreover, we have numerically confirmed the transitions using the time-dependent Ginzburg-Landau model describing phase separation and the bending elastic membrane, which is quantitatively consistent with experimental results by fixing one free parameter. Our findings suggest that the local spontaneous curvature due to the asymmetric composition plays an essential role in the thermodynamic stabilization of micro-phase separation in lipid bilayers.

  20. Rapid Impedance Measurement of Tethered Bilayer Lipid Membrane Biosensors

    E-print Network

    Mason, Andrew

    Rapid Impedance Measurement of Tethered Bilayer Lipid Membrane Biosensors Xiaoyi Mu, Daniel Rairigh of millisecond membrane protein activity in biosensor arrays. I. INTRODUCTION Because of the critical role membrane proteins play in biological function, biosensors utilizing membrane proteins have become

  1. Formation of Vesicles in Lipid - Liquid Crystal Colloidal Mixtures

    NASA Astrophysics Data System (ADS)

    Peters, Jeffrey; Iannacchione, Germano

    2014-03-01

    The formation and phase ordering / evolution has been studied in lipid and liquid crystal (LC) colloidal mixtures as a function of LC concentration and thermal history. The lipid used was 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC) while the liquid crystal was pentylcyanobiphenyl (5CB). POPC is a naturally occurring lipid in eukaryotic cell membranes and mimics many of the properties of human cell walls. 5CB is a polar liquid crystal that exhibits a thermodynamically stable orientationally ordered (nematic) state at room temperature. Colloidal dispersions were made at various 5CB and POPC concentrations in water and studied via optical microscopy (phase contrast, confocal, florescence, and cross-polarizing) to probe phase order and evolution as well as by calorimetry to study phase transformations. Very large vesicles were observed to form that appear to use 5CB droplets as scaffolds as well as a unique promotion of lipid crystallization within defect regions of nematic domains.

  2. Understanding and Targeting Lipid Metabolism of Mycobacterium tuberculosis 

    E-print Network

    Liu, Zhen

    2013-12-09

    Mycobacterium tuberculosis (M. tuberculosis) contains a wide array of genes responsible for the synthesis and secretion of a variety of bioactive lipids. The genes represent attractive drug-targets due to their involvement in essential cell cycles...

  3. Mixed Mechanism of Lubrication by Lipid Bilayer Stacks.

    PubMed

    Bo?an, Alexandru; Joly, Laurent; Fillot, Nicolas; Loison, Claire

    2015-11-10

    Although the key role of lipid bilayer stacks in biological lubrication is generally accepted, the mechanisms underlying their extreme efficiency remain elusive. In this article, we report molecular dynamics simulations of lipid bilayer stacks undergoing load and shear. When the hydration level is reduced, the velocity accommodation mechanism changes from viscous shear in hydration water to interlayer sliding in the bilayers. This enables stacks of hydrated lipid bilayers to act as efficient boundary lubricants for various hydration conditions, structures, and mechanical loads. We also propose an estimation for the friction coefficient; thanks to the strong hydration forces between lipid bilayers, the high local viscosity is not in contradiction with low friction coefficients. PMID:26381720

  4. Glycans pattern the phase behaviour of lipid membranes

    NASA Astrophysics Data System (ADS)

    Subramaniam, Anand Bala; Guidotti, Guido; Manoharan, Vinothan N.; Stone, Howard A.

    2013-02-01

    Hydrated networks of glycans (polysaccharides)—in the form of cell walls, periplasms or gel-like matrices—are ubiquitously present adjacent to cellular plasma membranes. Yet, despite their abundance, the function of glycans in the extracellular milieu is largely unknown. Here we show that the spatial configuration of glycans controls the phase behaviour of multiphase model lipid membranes: inhomogeneous glycan networks stabilize large lipid domains at the characteristic length scale of the network, whereas homogeneous networks suppress macroscopic lipid phase separation. We also find that glycan-patterned phase separation is thermally reversible—thus indicating that the effect is thermodynamic rather than kinetic—and that phase patterning probably results from a preferential interaction of glycans with ordered lipid phases. These findings have implications for membrane-mediated transport processes, potentially rationalize long-standing observations that differentiate the behaviour of native and model membranes and may indicate an intimate coupling between cellular lipidomes and glycomes.

  5. [Study on lipids and other volatile constituents in Pheretima aspergillum].

    PubMed

    Yang, D; Wang, F; Peng, J; Xiao, L; Su, W

    2000-01-01

    To study chemical constituents in Pheretima aspergillum, three kinds of fractions were obtained from this drug by soxhlet extraction with different solvents, and the chemical structures of thirty-six volatile components were identified by means of GC-MS. The eleven in ether fraction were all lipids and the relative content of non-saturated fatty acid was the highest(27.70%) such as oleic acid, linoleic acid, arachidonic acid and eicosatrienoic acid; There were eight lipids in acetone fraction (35.75%), which included one kind of nonsaturated fatty acid (linoleic acid); There were thirteen lipids in ethanol fraction (72.09%), which non-saturated fatty acid has never been detected. This study has determined the lipid composition in Pheretima aspergillum, especially non-saturated fatty acid, and afforded chemical base to cardio-cerebro-vascular therapy. PMID:12575114

  6. Structure, Stability, and Thermodynamics of Lamellar DNA-Lipid Complexes

    E-print Network

    Ben-Shaul, Avinoam

    of liposomal vectors for gene delivery, i.e., targeting of extracellular DNA into cell nuclei, fundamental choices of neutral ("helper") lipid; in the case of DOPE (dioleoylphosphatidylethanolamine), for example

  7. Modeling of cationic lipid-DNA complexes S. Maya and

    E-print Network

    Ben-Shaul, Avinoam

    is crucial for their further development and design as non-viral transfection vectors in gene ther- apy. From List of abbreviations: CL: cationic lipid DOPE: dioleoylphosphatidylethanolamine DOSPA: 2,3-dioleyloxy

  8. Control of Differentiation of a Mammary Cell Line by Lipids

    NASA Astrophysics Data System (ADS)

    Dulbecco, Renato; Bologna, Mauro; Unger, Michael

    1980-03-01

    A rat mammary cell line (LA7) undergoes spontaneous differentiation into domes due to production of specific inducers by the cells. Some of these inducers may be lipids, and we show that lipids regulate this differentiation as both inducers and inhibitors. One inhibitor is the tumor promoter tetradecanoyl-13 phorbol 12-acetate. The inducers are saturated fatty acids of two groups: butyric acid and acids with chain lengths from C13 to C16, especially myristic acid (C14). Other inducers are myristoyl and palmitoyl lysolecithins, myristic acid methyl ester, and two cationic detergents with a tetradecenyl chain. We propose that the lipids with a C14-C16 alkyl chain affect differentiation by recognizing specific receptors through their alkyl chains and that the effects obtained depend on the head groups. These lipids may be physiological regulators in the mammary gland.

  9. Polyphosphoinositide binding domains: key to inositol lipid biology

    PubMed Central

    Hammond, Gerald R. V.; Balla, Tamas

    2014-01-01

    Polyphosphoinositides (PPIn) are an important family of phospholipids located on the cytoplasmic leaflet of eukaryotic cell membranes. Collectively, they are critical for the regulation many aspects of membrane homeostasis and signaling, with notable relevance to human physiology and disease. This regulation is achieved through the selective interaction of these lipids with hundreds of cellular proteins, and thus the capability to study these localized interactions is crucial to understanding their functions. In this review, we discuss current knowledge of the principle types of PPIn-protein interactions, focusing on specific lipid-binding domains. We then discuss how these domains have been re-tasked by biologists as molecular probes for these lipids in living cells. Finally, we describe how the knowledge gained with these probes, when combined with other techniques, has led to the current view of the lipids’ localization and function in eukaryotes, focusing mainly on animal cells. PMID:25732852

  10. Phase Behavior of Lipid Monolayers Containing DPPC and Cholesterol Analogs

    E-print Network

    Stottrup, Benjamin L.

    Phase Behavior of Lipid Monolayers Containing DPPC and Cholesterol Analogs Benjamin L. Stottrup-active sterols'' in bilayers (cholesterol, epicholesterol, lathosterol, dihydrocholesterol, ergosterol of immiscibility in monolayers is not one of the biophysical attributes that explains cholesterol's predominance

  11. Nonequilibrium Behavior in Supported Lipid Membranes Containing Cholesterol

    E-print Network

    Stottrup, Benjamin L.

    Nonequilibrium Behavior in Supported Lipid Membranes Containing Cholesterol Benjamin L. Stottrup in giant unilamellar vesicles made from model mixtures of phospholipids and cholesterol (Dietrich et al, Dietrich et al. (2001) reported that depositing monolayers of phospholipids and cholesterol mixtures

  12. Shrimp Lipids: A Source of Cancer Chemopreventive Compounds

    PubMed Central

    López-Saiz, Carmen-María; Suárez-Jiménez, Guadalupe-Miroslava; Plascencia-Jatomea, Maribel; Burgos-Hernández, Armando

    2013-01-01

    Shrimp is one of the most popular seafoods worldwide, and its lipids have been studied for biological activity in both, muscle and exoskeleton. Free fatty acids, triglycerides, carotenoids, and other lipids integrate this fraction, and some of these compounds have been reported with cancer chemopreventive activities. Carotenoids and polyunsaturated fatty acids have been extensively studied for chemopreventive properties, in both in vivo and in vitro studies. Their mechanisms of action depend on the lipid chemical structure and include antioxidant, anti-proliferative, anti-mutagenic, and anti-inflammatory activities, among others. The purpose of this review is to lay groundwork for future research about the properties of the lipid fraction of shrimp. PMID:24135910

  13. Coatomer-dependent protein delivery to lipid droplets

    PubMed Central

    Soni, Krishnakant G.; Mardones, Gonzalo A.; Sougrat, Rachid; Smirnova, Elena; Jackson, Catherine L.; Bonifacino, Juan S.

    2009-01-01

    Summary Lipid droplets (LDs) are cytoplasmic organelles that store neutral lipids for use as an energy supply in times of nutrient deprivation and for membrane assembly. Misregulation of LD function leads to many human diseases, including lipodystrophy, obesity and neutral lipid storage disorders. A number of proteins have been shown to localize to the surface of lipid droplets, including lipases such as adipose triglyceride lipase (ATGL) and the PAT-domain proteins ADRP (adipophilin) and TIP47, but the mechanism by which they are targeted to LDs is not known. Here we demonstrate that ATGL and ADRP, but not TIP47, are delivered to LDs by a pathway mediated by the COPI and COPII coatomer proteins and their corresponding regulators. PMID:19461073

  14. Dual parallel mass spectrometry for lipid and vitamin D analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are numerous options for mass spectrometric analysis of lipids, including different types of ionization, and a wide variety of experiments using different scan modes that can be conducted. Atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) provide complementary ...

  15. Lipid accumulation by Rhodococcus rhodochrous grown on glucose.

    PubMed

    Shields-Menard, Sara A; Amirsadeghi, Marta; Sukhbaatar, Badamkhand; Revellame, Emmanuel; Hernandez, Rafael; Donaldson, Janet R; French, W Todd

    2015-05-01

    Biodiesel is an alternative fuel made from costly vegetable oil feedstocks. Some microorganisms can accumulate lipids when nutrients are limited and carbon is in excess. Rhodococcus rhodochrous is a gram-positive bacterium most often used in bioremediation or acrylamide production. The purpose of this study was to investigate and characterize the lipid accumulation capabilities of R. rhodochrous. Shake flasks and a large-scale fermentation were used to cultivate R. rhodochrous in varying concentrations of glucose. R. rhodochrous achieved almost 50 % of dry cell mass as lipid when grown in 20 g/L of glucose. Wax esters and triglycerides were identified in R. rhodochrous lipid extract. The transesterified extractables of R. rhodochrous consisted of mostly palmitic (35 %) and oleic (42 %) acid methyl esters. This study shows R. rhodochrous to be an oleaginous bacterium with potential for application in alternative fuels. PMID:25656153

  16. Asymmetric heat transfer from nanoparticles in lipid bilayers

    NASA Astrophysics Data System (ADS)

    Potdar, Dipti; Sammalkorpi, Maria

    2015-12-01

    Here, we use molecular dynamics simulations to characterize the heat transfer properties of lipid bilayer - gold nanoparticle systems in which the nanoparticle acts as a heat source. The focus is on dipalmitoylphosphatidylcholine (DPPC) lipid bilayers and thiolated alcohol and alkyl functionalized nanoparticles as prototype hydrophilic and hydrophobic nanoparticles. We find hydrophilic nanoparticles which are partly in contact with the surrounding water environment are more efficient in transferring heat to the system than hydrophobic ones which reside surrounded by the membrane. This is because of the hydrogen bonding capability of the hydroxy pentanethiol and the more efficient heat conductivity through water than the lipid bilayer. Additionally, we find the heat conductance is strongly asymmetric and has a discontinuity between the bilayer leaflets. In total, the findings provide understanding on heat transport from localized heat sources in lipid bilayers and could bear significance, e.g., in engineering and controlling photoactivated triggering of liposomal systems.

  17. Film Balance Studies of Membrane Lipids and Related Molecules

    ERIC Educational Resources Information Center

    Cadenhead, D. A.

    1972-01-01

    Discusses apparatus, techniques, and measurements used to determine cell membrane composition. The use of a film balance to study monolayer membranes of selected lipids is described and results reported. (TS)

  18. Anomalous diffusion of phospholipids and cholesterols in a lipid bilayer and its origins

    E-print Network

    Jae-Hyung Jeon; Hector Martinez-Seara Monne; Matti Javanainen; Ralf Metzler

    2012-10-19

    Combining extensive molecular dynamics simulations of lipid bilayer systems of varying chemical composition with single-trajectory analyses we systematically elucidate the stochastic nature of the lipid motion. We observe subdiffusion over more than four orders of magnitude in time, clearly stretching into the sub-microsecond domain. The lipid motion delicately depends on the lipid chemistry, the lipid phase, and especially on the presence of cholesterol. We demonstrate that fractional Langevin equation motion universally describes the lipid motion in all phases including the gel phase, and in the presence of cholesterol. The results underline the relevance of anomalous diffusion in lipid bilayers and the strong effects of the membrane composition.

  19. Targeting lipid biosynthesis and salvage in apicomplexan parasites for improved chemotherapies.

    PubMed

    Coppens, Isabelle

    2013-12-01

    Apicomplexa are some of the most widespread and poorly controlled pathogens in the world. The metabolism of lipids in these parasites, which include Plasmodium spp., Toxoplasma gondii and Cryptosporidium spp., is essential for the production of infectious progeny and pathogen persistence in their mammalian hosts. Metabolic maps of apicomplexan lipid syntheses reveal auxotrophies for many lipid species, which force these parasites to meet their high demand for lipids through networks of both synthesis and scavenging. Here, I review the unique lipid biosynthetic enzymes and lipid transporter systems of Apicomplexa, focusing on isoprenoids, sphingolipids and cholesterol, and highlight promising chemotherapeutic targets in the lipid synthetic and salvage pathways. PMID:24162026

  20. Lipidomic and proteomic analysis of Caenorhabditis elegans lipid droplets and identification of ACS-4 as a lipid droplet-associated protein.

    PubMed

    Vrablik, Tracy L; Petyuk, Vladislav A; Larson, Emily M; Smith, Richard D; Watts, Jennifer L

    2015-10-01

    Lipid droplets are cytoplasmic organelles that store neutral lipids for membrane synthesis and energy reserves. In this study, we characterized the lipid and protein composition of purified Caenorhabditis elegans lipid droplets. These lipid droplets are composed mainly of triacylglycerols, surrounded by a phospholipid monolayer composed primarily of phosphatidylcholine and phosphatidylethanolamine. The fatty acid composition of the triacylglycerols is rich in fatty acid species obtained from the dietary Escherichia coli, including cyclopropane fatty acids and cis-vaccenic acid. Unlike other organisms, C. elegans lipid droplets contain very little cholesterol or cholesterol esters. Comparison of the lipid droplet proteomes of wild type and high-fat daf-2 mutant strains shows a very similar proteome in both strains, except that the most abundant protein in the C. elegans lipid droplet proteome, MDT-28, is relatively less abundant in lipid droplets isolated from daf-2 mutants. Functional analysis of lipid droplet proteins identified in our proteomic studies indicated an enrichment of proteins required for growth and fat homeostasis in C. elegans. Finally, we confirmed the localization of one of the newly identified lipid droplet proteins, ACS-4. We found that ACS-4 localizes to the surface of lipid droplets in the C. elegans intestine and skin. This study bolsters C. elegans as a model to study the dynamics and functions of lipid droplets in a multicellular organism. PMID:26121959

  1. Lipid droplet mobilization: The different ways to loosen the purse strings.

    PubMed

    D'Andrea, Sabine

    2016-01-01

    Cytosolic lipid droplets are dynamic lipid-storage organelles that play a crucial role as reservoirs of metabolic energy and membrane precursors. These organelles are present in virtually all cell types, from unicellular to pluricellular organisms. Despite similar structural organization, lipid droplets are heterogeneous in morphology, distribution and composition. The protein repertoire associated to lipid droplet controls the organelle dynamics. Distinct structural lipid droplet proteins are associated to specific lipolytic pathways. The role of these structural lipid droplet-associated proteins in the control of lipid droplet degradation and lipid store mobilization is discussed. The control of the strictly-regulated lipolysis in lipid-storing tissues is compared between mammals and plants. Differences in the cellular regulation of lipolysis between lipid-storing tissues and other cell types are also discussed. PMID:26187474

  2. NucleusLipid droplet 0 100 200 300 400 500

    E-print Network

    Gross, Steven

    ) Lipid droplet NucleusPolar lipids l Control pre-loaded - Gluc (8h) P-AMPK AMPK P-ACC m AMPK activation after 8h glucose depletion 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 Initial - Gluc P-AMPK/AMPKvs Non-blotting of phosphorylated AMPK (upper panels), total AMPK (middle panels) or phospho-ACC (lower panels) in control and pre

  3. Balancing the fat: lipid droplets and human disease

    PubMed Central

    Krahmer, Natalie; Farese, Robert V; Walther, Tobias C

    2013-01-01

    Lipid droplets (LDs) are dynamic, cytosolic lipid-storage organelles found in nearly all cell types. Too many or too few LDs during excess or deficient fat storage lead to many different human diseases. Recent insights into LD biology and LD protein functions shed new light on mechanisms underlying those metabolic pathologies. These findings will likely provide opportunities for treatment of diseases associated with too much or too little fat. PMID:23740690

  4. Recording of Ion Channel Activity in Planar Lipid Bilayer Experiments

    PubMed Central

    Zakharian, Eleonora

    2013-01-01

    Planar lipid bilayer is an electrophysiological technique that enables study of functional activities of ion channels, porins, and other pore-forming molecular complexes. The main purpose of this method is to monitor ion channels’ behavior at the single molecule level in the artificial membranes. Here, I describe the details of this technique that will underline formation of the lipid bilayers and incorporation and activation of the ion channel protein. PMID:23529424

  5. Lipid production in Porphyridium cruentum grown under different culture conditions.

    PubMed

    Oh, Sung Ho; Han, Jae Gun; Kim, Young; Ha, Ji Hye; Kim, Seung Seop; Jeong, Myoung Hoon; Jeong, Hyang Suk; Kim, Na Young; Cho, Jeong Sub; Yoon, Won Byong; Lee, Shin Young; Kang, Do Hyung; Lee, Hyeon Yong

    2009-11-01

    Autotrophic growth of Porphyridium cruentum under 18:12 h and 12:12 h light:dark cycles showed the maximum cell concentration of 2.1 g-dry wt./L, whereas the specific growth rate, 0.042 (1/h), at 18:6 h is faster than that of 12:12 h, 0.031 (1/h), respectively. The highest lipid accumulation level, 19.3 (%, w/w), was achieved at 12:12 h cycle. Under dark cultivation condition with 10 g/L of glucose, the lipid accumulation in the cell was 10.9 (%, w/w), whereas the heterotrophic growth with glycerol as the carbon resource showed low level of cell concentration and lipid production, compared to that of glucose. The glucose was decided to be a suitable carbon resource for the heterotrophic growth of P. cruentum. The lipids from P. cruentum seemed be feasible for biodiesel production, because over 30% of the lipid was C16-C(18:1). The cultivation time and temperature were important factors to increase the maximum cell concentration. Extending the cultivation time helps maintain the maximum cell concentration, and higher lipid accumulation was achieved at 25 degrees C, compared to 35 degrees C. The fed-batch cultures showed that, under the light condition, the specific production rate was slightly decreased to 0.4% lipid/g-dry wt./day at the later stage, whereas, under the dark condition, the specific production rate was maintained to be a maximum value of 1.1% lipid/g-dry wt./day, even in the later stage of cultivation. The results indicate that the heterotrophic or 12:12 h cyclic mixotrophic growth of P. cruentum could be used for the production of biodiesel in long-term fed-batch cultivation of P. cruentum. PMID:19804869

  6. Charge Prediction of Lipid Fragments in Mass Spectrometry

    SciTech Connect

    Schrom, Brian T.; Kangas, Lars J.; Ginovska, Bojana; Metz, Thomas O.; Miller, John H.

    2011-12-18

    An artificial neural network is developed for predicting which fragment is charged and which fragment is neutral for lipid fragment pairs produced from a liquid chromatography tandem mass spectrometry simulation process. This charge predictor is integrated into software developed at PNNL for in silico spectra generation and identification of metabolites known as Met ISIS. To test the effect of including charge prediction in Met ISIS, 46 lipids are used which show a reduction in false positive identifications when the charge predictor is utilized.

  7. Mitochondrial and cellular mechanisms for managing lipid excess

    PubMed Central

    Aon, Miguel A.; Bhatt, Niraj; Cortassa, Sonia C.

    2014-01-01

    Current scientific debates center on the impact of lipids and mitochondrial function on diverse aspects of human health, nutrition and disease, among them the association of lipotoxicity with the onset of insulin resistance in skeletal muscle, and with heart dysfunction in obesity and diabetes. Mitochondria play a fundamental role in aging and in prevalent acute or chronic diseases. Lipids are main mitochondrial fuels however these molecules can also behave as uncouplers and inhibitors of oxidative phosphorylation. Knowledge about the functional composition of these contradictory effects and their impact on mitochondrial-cellular energetics/redox status is incomplete. Cells store fatty acids (FAs) as triacylglycerol and package them into cytoplasmic lipid droplets (LDs). New emerging data shows the LD as a highly dynamic storage pool of FAs that can be used for energy reserve. Lipid excess packaging into LDs can be seen as an adaptive response to fulfilling energy supply without hindering mitochondrial or cellular redox status and keeping low concentration of lipotoxic intermediates. Herein we review the mechanisms of action and utilization of lipids by mitochondria reported in liver, heart and skeletal muscle under relevant physiological situations, e.g., exercise. We report on perilipins, a family of proteins that associate with LDs in response to loading of cells with lipids. Evidence showing that in addition to physical contact, mitochondria and LDs exhibit metabolic interactions is presented and discussed. A hypothetical model of channeled lipid utilization by mitochondria is proposed. Direct delivery and channeled processing of lipids in mitochondria could represent a reliable and efficient way to maintain reactive oxygen species (ROS) within levels compatible with signaling while ensuring robust and reliable energy supply. PMID:25132820

  8. Enhanced roughness of lipid membranes caused by external electric fields

    E-print Network

    M Neek-Amal; H. Rafii-Tabar; H. R. Sepangi

    2007-05-17

    The behavior of lipid membranes in the presence of an external electric field is studied and used to examine the influence of such fields on membrane parameters such as roughness and show that for a micro sized membrane, roughness grows as the field increases. The dependence of bending rigidity on the electric field is also studied and an estimation of thickness of the accumulated charges around lipid membranes in a free-salt solution is presented.

  9. Proteomic Profiling of Detergent Resistant Membranes (Lipid Rafts) of Prostasomes.

    PubMed

    Dubois, Louise; Ronquist, Karl K Göran; Ek, Bo; Ronquist, Gunnar; Larsson, Anders

    2015-11-01

    Prostasomes are exosomes derived from prostate epithelial cells through exocytosis by multivesicular bodies. Prostasomes have a bilayered membrane and readily interact with sperm. The membrane lipid composition is unusual with a high contribution of sphingomyelin at the expense of phosphatidylcholine and saturated and monounsaturated fatty acids are dominant. Lipid rafts are liquid-ordered domains that are more tightly packed than the surrounding nonraft phase of the bilayer. Lipid rafts are proposed to be highly dynamic, submicroscopic assemblies that float freely within the liquid disordered membrane bilayer and some proteins preferentially partition into the ordered raft domains. We asked the question whether lipid rafts do exist in prostasomes and, if so, which proteins might be associated with them. Prostasomes of density range 1.13-1.19g/ml were subjected to density gradient ultracentrifugation in sucrose fabricated by phosphate buffered saline (PBS) containing 1% Triton X-100 with capacity for banding at 1.10 g/ml, i.e. the classical density of lipid rafts. Prepared prostasomal lipid rafts (by gradient ultracentrifugation) were analyzed by mass spectrometry. The clearly visible band on top of 1.10g/ml sucrose in the Triton X-100 containing gradient was subjected to liquid chromatography-tandem MS and more than 370 lipid raft associated proteins were identified. Several of them were involved in intraluminal vesicle formation, e.g. tetraspanins, ESCRTs, and Ras-related proteins. This is the first comprehensive liquid chromatography-tandem MS profiling of proteins in lipid rafts derived from exosomes. Data are available via ProteomeXchange with identifier PXD002163. PMID:26272980

  10. Estimation of lipids and lean mass of migrating sandpipers

    USGS Publications Warehouse

    Skagen, Susan K.; Knopf, Fritz L.; Cade, Brian S.

    1993-01-01

    Estimation of lean mass and lipid levels in birds involves the derivation of predictive equations that relate morphological measurements and, more recently, total body electrical conductivity (TOBEC) indices to known lean and lipid masses. Using cross-validation techniques, we evaluated the ability of several published and new predictive equations to estimate lean and lipid mass of Semipalmated Sandpipers (Calidris pusilla) and White-rumped Sandpipers (C. fuscicollis). We also tested ideas of Morton et al. (1991), who stated that current statistical approaches to TOBEC methodology misrepresent precision in estimating body fat. Three published interspecific equations using TOBEC indices predicted lean and lipid masses of our sample of birds with average errors of 8-28% and 53-155%, respectively. A new two-species equation relating lean mass and TOBEC indices revealed average errors of 4.6% and 23.2% in predicting lean and lipid mass, respectively. New intraspecific equations that estimate lipid mass directly from body mass, morphological measurements, and TOBEC indices yielded about a 13% error in lipid estimates. Body mass and morphological measurements explained a substantial portion of the variance (about 90%) in fat mass of both species. Addition of TOBEC indices improved the predictive model more for the smaller than for the larger sandpiper. TOBEC indices explained an additional 7.8% and 2.6% of the variance in fat mass and reduced the minimum breadth of prediction intervals by 0.95 g (32%) and 0.39 g (13%) for Semipalmated and White-rumped Sandpipers, respectively. The breadth of prediction intervals for models used to predict fat levels of individual birds must be considered when interpreting the resultant lipid estimates.

  11. Effects of hormones on lipids and lipoproteins

    SciTech Connect

    Krauss, R.M.

    1991-12-01

    Levels of plasma lipids and lipoproteins are strong predictors for the development of atherosclerotic cardiovascular disease in postmenopausal women. In women, as in men, numerous factors contribute to variations in plasma lipoproteins that may affect cardiovascular disease risk. These include age, dietary components, adiposity, genetic traits, and hormonal changes. Each of these factors may operate to varying degrees in determining changes in plasma lipoprotein profiles accompanying menopause- Cross-sectional and longitudinal studies have suggested increases in levels of cholesterol, low density lipoproteins (LDL) and triglyceride-rich lipoproteins associated with menopause. High density lipoproteins (HDL), which are higher in women than men and are thought to contribute to relative protection of premenopausal women from cardiovascular disease, remain relatively constant in the years following menopause, although small, and perhaps transient reductions in the HDL{sub 2} subfraction have been reported in relation to reduced estradiol level following menopause. Despite these associations, it has been difficult to determine the role of endogenous hormones in influencing the plasma lipoproteins of postmenopausal women. In principle, the effects of hormone replacement should act to reverse any alterations in lipoprotein metabolism that are due to postmenopausal hormone changes. While there may be beneficial effects on lipoproteins, hormone treatment does not restore a premenopausal lipoprotein profile. Furthermore, it is not dear to what extent exogenous hormone-induced lipoprotein changes contribute to the reduced incidence of cardiovascular disease with hormone replacement therapy.

  12. Complex Lipids of Rhodomicrobium vannielii1

    PubMed Central

    Park, Chong-Eel; Berger, Leslie R.

    1967-01-01

    Eight components, seven of which contained phosphorus, were found in the phospholipid fraction of Rhodomicrobium vannielii. The major components were lipoamino acid (o-ornithine ester of phosphatidyl glycerol, 46.5%) and phosphatidyl choline (26.5%). The other six components were phosphatidyl glycerol (9.7%), bisphosphatidic acid (6.7%), phosphatidyl ethanolamine (4.5%), phosphatidic acid (1.8%), lysophosphatidyl glycerol-o-ornithine ester (3.2%), and N,N-ornithine amide of unidentified fatty acid (0.95%). Total phospholipid accounted for 4.2% of cell dry weight. The major fatty acid was vaccenic acid, C18:1, which accounted for approximately 90% of the total fatty acids of the complex lipid fraction. The other four fatty acids were C16:0 (6.25%), C18:0 (3.8%), C14:0 (0.7%), and C16:1 (0.35%). The sulfolipid content was 0.01% of the cell dry weight or 0.14 ?moles per g of dried cells, assuming that its fatty acid component is vaccenic acid. No steroids were detected. PMID:6020408

  13. Proteomic analysis of murine testes lipid droplets

    PubMed Central

    Wang, Weiyi; Wei, Suning; Li, Linghai; Su, Xueying; Du, Congkuo; Li, Fengjuan; Geng, Bin; Liu, Pingsheng; Xu, Guoheng

    2015-01-01

    Testicular Leydig cells contain abundant cytoplasmic lipid droplets (LDs) as a cholesteryl-ester store for releasing cholesterols as the precursor substrate for testosterone biosynthesis. Here, we identified the protein composition of testicular LDs purified from adult mice by using mass spectrometry and immunodetection. Among 337 proteins identified, 144 were previously detected in LD proteomes; 44 were confirmed by microscopy. Testicular LDs contained multiple Rab GTPases, chaperones, and proteins involved in glucuronidation, ubiquination and transport, many known to modulate LD formation and LD-related cellular functions. In particular, testicular LDs contained many members of both the perilipin family and classical lipase/esterase superfamily assembled predominately in adipocyte LDs. Thus, testicular LDs might be regulated similar to adipocyte LDs. Remarkably, testicular LDs contained a large number of classical enzymes for biosynthesis and metabolism of cholesterol and hormonal steroids, so steroidogenic reactions might occur on testicular LDs or the steroidogenic enzymes and products could be transferred through testicular LDs. These characteristics differ from the LDs in most other types of cells, so testicular LDs could be an active organelle functionally involved in steroidogenesis. PMID:26159641

  14. GPCR crystallization using lipidic cubic phase technique.

    PubMed

    Yin, Xin; Xu, Henghao; Hanson, Michael; Liu, Wei

    2014-01-01

    G protein-coupled receptors (GPCRs), a family of seven-transmembrane receptors, are among the most important drug targets with over half of all marketed drugs targeting the family. However, only a handful of easily druggable GPCRs are successfully targeted by pharmaceuticals. Efforts to shift this intensive focus to other, more recalcitrant GPCR targets will increasingly draw on new information such as structural details, which have until recently proven tremendously challenging to gather for this class of protein receptors due to the difficulties in obtaining diffraction-quality crystals. Recently, the development and application of lipidic cubic phase (LCP) technology has reduced one major hurdle for crystallization of GPCRs, with 22 unique receptors being structurally characterized from LCP grown crystals over the span of seven years. This review focuses on the technological improvements for LCP that have led to its successful utilization on the GPCR family, including the most recent combination of LCP with the X-ray free-electron laser that dramatically reduces requirements on crystal size, and holds significant promise for shortening timelines for structure determination and for accessing previously unattainable structures such as those of signaling complexes. PMID:25248558

  15. Vinpocetine attenuates lipid accumulation and atherosclerosis formation

    SciTech Connect

    Cai, Yujun; Li, Jian-Dong; Yan, Chen

    2013-05-10

    Highlights: •Vinpocetine attenuates hyperlipidemia-induced atherosclerosis in a mouse model. •Vinpocetine antagonizes ox-LDL uptake and accumulation in macrophages. •Vinpocetine blocks the induction of ox-LDL receptor LOX-1 in vitro and in vivo. -- Abstract: Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis.

  16. Lipid rafts, ceramide and molecular transcytosis.

    PubMed

    Bian, Fang; Xiong, Bin; Yang, Xiaoyan; Jin, Si

    2016-01-01

    Transcytosis, a widely described process concerning transport of macromolecules between the apical and basolateral sides in various cell types, is extremely important for multicellular organisms to selectively exchange materials in different microenvironments while maintaining cellular and body homeostasis. Uncontrolled transcytosis is involved in a wide range of pathophysiological processes. Lipid rafts (LRs), the sphingolipid and cholesterol-enriched membrane microdomains, enable to form different functional membrane macrodomains or platforms upon stimulations. In particular, ceramide-enriched membrane microdomains play extremely critical roles in LRs clustering or platform formations. Notably, various transcytosis-related molecules are tightly correlated with LRs and ceramide. We attempt to summarize the basic and advanced information about the roles of different types of transcytosis in human health and diseases, and the types and functions of LRs involved in transcytosis, as well as multiple transcytosis-related molecules associated with LRs and ceramide. It is hoped that all information and discussions could provide much more comprehensive insights into the understanding of the association of LRs with transcytosis, as well as shed some new light on the translational significance in this area. PMID:26709807

  17. Phenolic lipid ingredients from cashew nuts.

    PubMed

    Suo, Maorong; Isao, Hasegawa; Ishida, Yoshihiro; Shimano, Yasoku; Bi, Changxiao; Kato, Hikaru; Takano, Fumihide; Ohta, Tomihisa

    2012-01-01

    Five new phenolic lipids, 2-(8"Z-eicosenoyl)-6-(8'Z-pentadecenyl) salicylic acid (3), 2-(9"Z-hexadecenoyl)-6-(8'Z, 11'Z-pentadecadienyl) methyl salicylate (5), 2-(10"Z, 13"Z-nonadecadienoyl)-6-(8'Z, 11'Z-pentadecadienyl) salicylic acid (6), 2-(16"Z-pentacosenoyl)-6-(8'Z-pentadecenyl) salicylic acid (7) and 2-(9"Z-octadecenoyl)-6-(8'Z, 11'Z-pentadecadienyl) methyl salicylate (8), and three known compounds, cardols (1), anacardic acid (2) and cardanols (4), were isolated from the nuts of the cashew, Anacardium occidentale L. The structures were established on the basis of detailed MS and NMR spectroscopic analyses. Compound 1 highly enhanced both Th-1 (IL-2, IFN-?) and Th-2 (IL-4, IL-5) cytokine production, and compounds 7 and 8 highly increased cytokine IL-2 and IFN-? production in response to concanavalin A in cultured murine Peyer's patch cells ex vivo. The isolated compounds showed moderate inhibitory activities on cytochrome CYP3A4 enzyme. PMID:21735238

  18. Lean beef: impetus for lipid modifications.

    PubMed

    Sweeten, M K; Cross, H R; Smith, G C; Savell, J W; Smith, S B

    1990-01-01

    Health-conscious consumers want lean beef. The beef industry has responded by physically removing much of the adipose tissue from retail products and by initiating attempts to produce--genetically and environmentally--cattle with more muscle, less external fat, and less seam fat, without sacrificing the quality dependent on the amount of marbling present. Offering lean beef that is closely or completely trimmed of external fat has improved retail beef sales. Impetus for modification of the lipid composition of bovine muscle and adipose tissue, including marbling, has resulted from the following: (a) diet/health concerns of consumers and demands for leaner beef, (b) research clarifying effects of dietary fatty acids and cholesterol on serum cholesterol levels, (c) dietary guidelines and recommendations from health organizations, and (d) dietary recommendations by physicians and dietitians to reduce beef consumption. Analysis of cholesterol content of marbling dissected from the rib (longissimus dorsi) muscle revealed that marbling contributes little to total cholesterol content. Cholesterol content of marbling was 117 mg/100 gm intramuscular adipose tissue (equivalent to about a 2 mg cholesterol contribution to a 100-gm serving of uncooked meat). The difference in fatty acid composition of lean meat and of adipose tissue is primarily in the percentage of polyunsaturated fatty acids, which is higher in lean meat. The most prevalent fatty acids in adipose tissue including marbling were: palmitic acid (24.1%), stearic acid (13.5%), and oleic acid (37.7%). PMID:2404051

  19. Prebiotics and Lipid Metabolism: A Review.

    PubMed

    Sharma, Smriti; Puri, Seema

    2015-08-01

    Coronary heart disease (CHD) is the leading cause of morbidity and mortality worldwide. Modifiable risk factors of CHD have been identified, including high levels of low-density lipoproteins (LDLs) and triglycerides (TGs). Attempts by various researchers have been made to alter them. Several approaches, both pharmacological and nonpharmacological, have been identified to deal with the soaring numbers of individuals with those high levels. Current CHD treatment includes dietary interventions and use of statins, fibrates, niacin, cholesterol absorption inhibitors, and bile acid sequestrants. Those formulations have limitations and can possess long-term, unwanted side effects, and, therefore, other cholesterol-lowering, dietary adjuncts need to be identified and supplemented. Prebiotics are indigestible, fermented food substrates that selectively stimulate the growth and increase the activity of 1 or a limited number of microbial genus species, thereby changing the composition of the gut microbiota to confer health benefits to the hosts. Prebiotics are also nondigestible carbohydrates with specific fermentative properties, stimulating specific microbial growth associated with health and well-being. Some animal and human studies have provided strong evidence that suggests that prebiotics, as functional foods, can positively alter an individual's serum lipid profile, thereby lowering his or her risk of developing CHD. Therefore, the current review focuses on evaluating the role of prebiotics as potential dietary adjuncts in lowering cholesterol levels, with the aim of reducing the risks of cardiovascular and CHD. PMID:26348612

  20. Phytosterols, Lipid Administration, and Liver Disease During Parenteral Nutrition.

    PubMed

    Zaloga, Gary P

    2015-09-01

    Phytosterols are plant-derived sterols that are structurally and functionally analogous to cholesterol in vertebrate animals. Phytosterols are found in many foods and are part of the normal human diet. However, absorption of phytosterols from the diet is minimal. Most lipid emulsions used for parenteral nutrition are based on vegetable oils. As a result, phytosterol administration occurs during intravenous administration of lipid. Levels of phytosterols in the blood and tissues may reach high levels during parenteral lipid administration and may be toxic to cells. Phytosterols are not fully metabolized by the human body and must be excreted through the hepatobiliary system. Accumulating scientific evidence suggests that administration of high doses of intravenous lipids that are high in phytosterols contributes to the development of parenteral nutrition-associated liver disease. In this review, mechanisms by which lipids and phytosterols may cause cholestasis are discussed. Human studies of the association of phytosterols with liver disease are reviewed. In addition, clinical studies of lipid/phytosterol reduction for reversing and/or preventing parenteral nutrition associated liver disease are discussed. PMID:26177665