Sample records for sleep-inducing lipid oleamide

  1. Fatty acid amide hydrolase: biochemistry, pharmacology, and therapeutic possibilities for an enzyme hydrolyzing anandamide, 2-arachidonoylglycerol, palmitoylethanolamide, and oleamide 1 1 Abbreviations: AEA, anandamide, arachidonyl ethanolamide; PEA, palmitoylethanolamide, N-(2-hydroxyethyl) hexadecamide; FAAH, fatty acid amide hydrolase; CB, cannabinoid; PMSF, phenylmethylsulfonyl fluoride; MAFP, methyl arachidonyl fluorophosphonate; methAEA, arachidonyl-1?-hydroxy-2?-propylamide; and NSAIDs, nonsteroidal anti-inflammatory drugs

    Microsoft Academic Search

    Christopher J Fowler; Kent-Olov Jonsson; Gunnar Tiger

    2001-01-01

    Fatty acid amide hydrolase (FAAH) is responsible for the hydrolysis of a number of important endogenous fatty acid amides, including the endogenous cannabimimetic agent anandamide (AEA), the sleep-inducing compound oleamide, and the putative anti-inflammatory agent palmitoylethanolamide (PEA). In recent years, there have been great advances in our understanding of the biochemical and pharmacological properties of the enzyme. In this commentary,

  2. Enhanced radiosensitization of p53 mutant cells by oleamide

    SciTech Connect

    Lee, Yoon-Jin [Laboratory of Radiation Effect, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Chung, Da Yeon [Laboratory of Radiation Effect, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Lee, Su-Jae [Laboratory of Experimental Radiation Therapeutics, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Ja Jhon, Gil [Laboratory of Radiation Effect, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Laboratory of Experimental Radiation Therapeutics, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Division of Molecular Life Science, Ewha Woman's University, Seoul (Korea, Republic of); Lee, Yun-Sil [Laboratory of Radiation Effect, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)]. 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.

  3. Pharmacological Activity of Fatty Acid Amides Is Regulated, but Not Mediated, by Fatty Acid Amide Hydrolase in Vivo

    Microsoft Academic Search

    ARON H. LICHTMAN; E. GREGORY HAWKINS; GRAEME GRIFFIN; BENJAMIN F. CRAVATT

    2002-01-01

    Fatty acid amides (FAAs) represent a class of neuromodulatory lipids that includes the endocannabinoid anandamide and the sleep-inducing substance oleamide. Both anandamide and ole- amide produce behavioral effects indicative of cannabinoid activity, but only anandamide binds the cannabinoid (CB1) receptor in vitro. Accordingly, oleamide has been proposed to induce its behavioral effects by serving as a competitive sub- strate for

  4. Efficiency Enhancement of Inverted Structure Perovskite Solar Cells via Oleamide Doping of PCBM Electron Transport Layer.

    PubMed

    Xia, Fei; Wu, Qiliang; Zhou, Pengcheng; Li, Yi; Chen, Xiang; Liu, Qing; Zhu, Jun; Dai, Songyuan; Lu, Yalin; Yang, Shangfeng

    2015-06-24

    An amphiphilic surfactant, oleamide, was applied to dope the PCBM electron transport layer (ETL) of inverted structure perovskite solar cells (ISPSCs), resulting in a dramatic efficiency enhancement. Under the optimized oleamide doping ratio of 5.0 wt %, the power conversion efficiency of the CH3NH3PbIxCl3-x perovskite-based ISPSC device is enhanced from 10.05% to 12.69%, and this is primarily due to the increases of both fill factor and short-circuit current. According to the surface morphology study of the perovskite/PCBM bilayer film, oleamide doping improves the coverage of PCBM ETL onto the perovskite layer, and this is beneficial for the interfacial contact between the perovskite layer and the Ag cathode and consequently the electron transport from perovskite to the Ag cathode. Such an improved electron transport induced by oleamide doping is further evidenced by the impedance spectroscopic study, revealing the prohibited electron-hole recombination at the interface between the perovskite layer and the Ag cathode. PMID:26053101

  5. Sleep-Inducing Substances in the Regulation of Sleep

    Microsoft Academic Search

    Vijay Ramesh; Navita Kaushal; Velayudhan Mohan Kumar

    \\u000a We spend almost one-third of our life sleeping, yet very little is understood as to why we need sleep or how do we sleep.\\u000a The extrinsic and intrinsic controlling mechanisms of sleep have fascinated scientists for generations and many different\\u000a theories, networks and endogenous compounds have been proposed. Although various substances are labeled 'sleep-inducing substances'\\u000a for example, delta sleep inducing

  6. Interaction of delta sleep-inducing peptide and its analogues with cellular membranes: A structure-function analysis

    Microsoft Academic Search

    I. I. Mikhaleva; G. T. Rikhireva; I. A. Prudchenko; I. N. Golubev

    2006-01-01

    The possibility of a correlation between the membrane properties of the delta sleep-inducing peptide (DSIP) and its analogues\\u000a and their biological activity in vivo was examined by a comparative study of the membrane effects of these peptides. The peptides\\u000a exhibiting biological activity in vivo were shown to cause a statistically reliable disordering of lipids in thrombocyte plasma\\u000a membranes similar to

  7. Differential proteomic analysis of the anti-depressive effects of oleamide in a rat chronic mild stress model of depression.

    PubMed

    Ge, Lin; Zhu, Ming-Ming; Yang, Jing-Yu; Wang, Fang; Zhang, Rong; Zhang, Jing-Hai; Shen, Jing; Tian, Hui-Fang; Wu, Chun-Fu

    2015-04-01

    Depression is a complex psychiatric disorder, and its etiology and pathophysiology are not completely understood. Depression involves changes in many biogenic amine, neuropeptide, and oxidative systems, as well as alterations in neuroendocrine function and immune-inflammatory pathways. Oleamide is a fatty amide which exhibits pharmacological effects leading to hypnosis, sedation, and anti-anxiety effects. In the present study, the chronic mild stress (CMS) model was used to investigate the antidepressant-like activity of oleamide. Rats were exposed to 10weeks of CMS or control conditions and were then subsequently treated with 2weeks of daily oleamide (5mg/kg, i.p.), fluoxetine (10mg/kg, i.p.), or vehicle. Protein extracts from the hippocampus were then collected, and hippocampal maps were generated by way of two-dimensional gel electrophoresis (2-DE). Altered proteins induced by CMS and oleamide were identified through mass spectrometry and database searches. Compared to the control group, the CMS rats exhibited significantly less body weight gain and decreased sucrose consumption. Treatment with oleamide caused a reversal of the CMS-induced deficit in sucrose consumption. In the proteomic analysis, 12 protein spots were selected and identified. CMS increased the levels of adenylate kinase isoenzyme 1 (AK1), nucleoside diphosphate kinase B (NDKB), histidine triad nucleotide-binding protein 1 (HINT1), acyl-protein thioesterase 2 (APT-2), and glutathione S-transferase A4 (GSTA4). Compared to the CMS samples, seven spots changed significantly following treatment with oleamide, including GSTA4, glutathione S-transferase A6 (GSTA6), GTP-binding nuclear protein Ran (Ran-GTP), ATP synthase subunit d, transgelin-3, small ubiquitin-related modifier 2 (SUMO2), and eukaryotic translation initiation factor 5A-1 (eIF5A1). Of these seven proteins, the level of eIF5A1 was up-regulated, whereas the remaining proteins were down-regulated. In conclusion, oleamide has antidepressant-like properties in the CMS rat model. The identification of proteins altered by CMS and oleamide treatment provides support for targeting these proteins in the development of novel therapies for depression. PMID:25641667

  8. Sleep Inducing Virtual Character Using Eye Contact Communication System

    E-print Network

    Tanaka, Jiro

    1 2 3 HMD Sleep Inducing Virtual Character Using Eye Contact Communication System Takumi Negishi 1 patients cannot move their hands. 1. (HMD: Head Mounted Dis- play) Cola¸co Mime[1] Ardouin FlyVIZ[2] HMD HMD 1 School of Infomatics, College of Information Science, Uni- versity of Tsukuba 2 NEC / NEC

  9. Delta Sleep-Inducing Peptide in the Rat Brain: An Immunohistological Microscopic Study

    Microsoft Academic Search

    J. Constantinidis; C. Bouras; R. Guntern; C. H. Taban; R. Tissot

    1983-01-01

    The authors have developed a method which makes it possible, for the first time, to visualize the delta sleep-inducing peptide in histological preparations and study it under the light and fluorescence microscope. Their research builds on Monnier’s discovery, in 1963, of a humoral hypnogenic factor in rabbits which was subsequently isolated and identified as a nonapeptide. Dubbed delta sleep-inducing peptide

  10. Effect of delta sleep-inducing peptide on macromolecule biosynthesis in brain tissue of stressed rodents

    Microsoft Academic Search

    M. G. Makletsova; I. I. Mikhaleva; I. A. Prudchenko; G. T. Rikhireva

    2006-01-01

    For evaluation of the nature of adaptogenic properties of delta sleep-inducing peptide we studied the effect of this substance\\u000a on macromolecule biosynthesis in the brain of rats and mice exposed to burn injury and psychoemotional stress, respectively.\\u000a Anabolic activity of delta sleep-inducing peptide depended on the purpose of adaptation corresponding to the type of stress.

  11. Lipids

    NSDL National Science Digital Library

    Reich, Ieva

    Quiz questions from the organic chemistry question bank provide students with an excellent opportunity to review key concepts. This group of questions focuses on fat soluble molecules called lipids. Questions on fatty acids, triacylglycerols, terpenes, and steroids are all provided here for review.

  12. Lipids

    NSDL National Science Digital Library

    Paul Anderson

    2013-03-12

    Paul Anderson describes the lipids (of the fats). He explains how they are an important source of energy but are also required to cell membranes. He explains how the hydrocarbon tails in triglycerides contain energy available for life. He also explains how phospholipids construct, and cholesterol molecules main the cell membrane.

  13. An endogenous sleep-inducing compound is a novel competitive inhibitor of fatty acid amide hydrolase

    Microsoft Academic Search

    Matthew P. Patricelli; Jean E. Patterson; Dale L. Boger; Benjamin F. Cravattb

    1998-01-01

    2-Octyl ?-bromoacetoacetate (O?Br), an endogenous compound originally isolated from human cerebrospinal fluid (CSF), has previously been demonstrated to increase REM sleep duration in cats. Based on the chemical structure of O?Br and its reported sleep-inducing effects, we synthesized O?Br along with chemically related analogs and tested these compounds as inhibitors of fatty acid amide hydrolase (FAAH), a brain enzyme that

  14. Mechanism of biological effect of the delta-sleep-inducing peptide includes activation of deoxyribonucleotide synthesis

    Microsoft Academic Search

    G. T. Rikhireva; M. K. Pulatova; V. L. Sharigin; M. G. Makletsova; I. I. Mikhaleva

    2009-01-01

    To find out the mechanism of oncoprotective effects of the delta-sleep-inducing peptide, we have studied the dynamics of ribonucleotide\\u000a reductase activity, which is a vital enzyme in the DNA biosynthesis, using electron paramagnetic resonance (EPR), and a concentration\\u000a of low molecular mass iron complexes in the murine spleen after intraperitoneal injection of the peptide and the antitumor\\u000a preparation methylnitrosourea. The

  15. Delta sleep-inducing peptide and Deltaran: Potential approaches to antistress protection

    Microsoft Academic Search

    E. V. Koplik; P. E. Umryukhin; I. L. Konorova; O. L. Terekhina; I. I. Mikhaleva; I. V. Gannushkina; K. V. Sudakov

    2008-01-01

    The aims of the present work were to perform a comparative study of the effects of delta sleep-inducing peptide and Deltaran\\u000a on neurons in emotiogenic brain structures and to address the question of whether it is possible to prevent or decrease the\\u000a negative influences of stress loads on the severity of subsequent cerebral ischemia in rats, using glycine with delta

  16. Delta sleep-inducing peptide and its tetrapeptide analogue alleviate severity of metaphit seizures

    Microsoft Academic Search

    Olivera Stanojlovi?; Dragana Živanovi?; Slobodan Mirkovi?; Inessa Mikhaleva

    2004-01-01

    The effects of delta sleep-inducing peptide (DSIP) and its tetrapeptide analogue, DSIP(1-4), on metaphit-induced audiogenic seizures were studied. Five groups of adult male Wistar rats were intraperitoneally treated with (1) saline, (2) metaphit, (3) DSIP, (4) metaphit+DSIP and (5) metaphit+DSIP(1-4). To examine blocking effects of DSIP and its analogue on fully developed metaphit seizures, the last two groups were injected

  17. Preventive effects of a fermented dairy product against Alzheimer's disease and identification of a novel oleamide with enhanced microglial phagocytosis and anti-inflammatory activity.

    PubMed

    Ano, Yasuhisa; Ozawa, Makiko; Kutsukake, Toshiko; Sugiyama, Shinya; Uchida, Kazuyuki; Yoshida, Aruto; Nakayama, Hiroyuki

    2015-01-01

    Despite the ever-increasing number of patients with dementia worldwide, fundamental therapeutic approaches to this condition have not been established. Epidemiological studies suggest that intake of fermented dairy products prevents cognitive decline in the elderly. However, the active compounds responsible for the effect remain to be elucidated. The present study aims to elucidate the preventive effects of dairy products on Alzheimer's disease and to identify the responsible component. Here, in a mouse model of Alzheimer's disease (5xFAD), intake of a dairy product fermented with Penicillium candidum had preventive effects on the disease by reducing the accumulation of amyloid ? (A?) and hippocampal inflammation (TNF-? and MIP-1? production), and enhancing hippocampal neurotrophic factors (BDNF and GDNF). A search for preventive substances in the fermented dairy product identified oleamide as a novel dual-active component that enhanced microglial A? phagocytosis and anti-inflammatory activity towards LPS stimulation in vitro and in vivo. During the fermentation, oleamide was synthesized from oleic acid, which is an abundant component of general dairy products owing to lipase enzymatic amidation. The present study has demonstrated the preventive effect of dairy products on Alzheimer's disease, which was previously reported only epidemiologically. Moreover, oleamide has been identified as an active component of dairy products that is considered to reduce A? accumulation via enhanced microglial phagocytosis, and to suppress microglial inflammation after A? deposition. Because fermented dairy products such as camembert cheese are easy to ingest safely as a daily meal, their consumption might represent a preventive strategy for dementia. PMID:25760987

  18. [Effects of delta sleep-inducing peptide on the intercentral integration during experimental epilepsy].

    PubMed

    Popova, N S; Adrianov, O S; Veskov, R; Iankovich, B; Rakich, L

    1989-08-01

    In free behavior experiments on cats it has been shown, that the intraperitoneal injection of delta-sleep-inducing peptide (100 mg/kg) may change organization of the pathology integration-epileptic discharges did not spread all the structures simultaneously. The slow-waves were registered in central medium of the thalamus and nucl. caudati. The epileptic discharges were registered first in visual and auditory cortex, hippocampus. After that they were observed in the motor cortex, nucl. caudati and centrum medianum of the thalamus. PMID:2804316

  19. Delta-sleep inducing peptide entrapment in the charged macroporous matrices.

    PubMed

    Sukhanova, Tatiana V; Artyukhov, Alexander A; Gurevich, Yakov M; Semenikhina, Marina A; Prudchenko, Igor A; Shtilman, Mikhail I; Markvicheva, Elena A

    2014-09-01

    Various biomolecules, for example proteins, peptides etc., entrapped in polymer matrices, impact interactions between matrix and cells, including stimulation of cell adhesion and proliferation. Delta-sleep inducing peptide (DSIP) possesses numerous beneficial properties, including its abilities in burn treatment and neuronal protection. DSIP entrapment in two macroporous polymer matrices based on copolymer of dimethylaminoethyl methacrylate and methylen-bis-acrylamide (Co-DMAEMA-MBAA) and copolymer of acrylic acid and methylen-bis-acrylamide (Co-AA-MBAA) has been studied. Quite 100% of DSIP has been entrapped into positively charged Co-DMAEMA-MBAA matrix, while the quantity of DSIP adsorbed on negatively charged Co-AA-MBAA was only 2-6%. DSIP release from Co-DMAEMA-MBAA was observed in saline solutions (0.9% NaCl and PBS) while there was no DSIP release in water or 25% ethanol, thus ionic strength was a reason of this process. PMID:25063142

  20. Membrane protein crystallization in meso: lipid type-tailoring of the cubic phase.

    PubMed Central

    Cherezov, Vadim; Clogston, Jeffrey; Misquitta, Yohann; Abdel-Gawad, Wissam; Caffrey, Martin

    2002-01-01

    Hydrated monoolein forms the cubic-Pn3m mesophase that has been used for in meso crystallization of membrane proteins. The crystals have subsequently provided high-resolution structures by crystallographic means. It is possible that the hosting cubic phase created by monoolein alone, which itself is not a common membrane component, will limit the range of membrane proteins crystallizable by the in meso method. With a view to expanding the range of applicability of the method, we investigated by x-ray diffraction the degree to which the reference cubic-Pn3m phase formed by hydrated monoolein could be modified by other lipid types. These included phosphatidylcholine (PC), phosphatidylethanolamine, phosphatidylserine, cardiolipin, lyso-PC, a polyethylene glycol-lipid, 2-monoolein, oleamide, and cholesterol. The results show that all nine lipids were accommodated in the cubic phase to some extent without altering phase identity. The positional isomer, 2-monoolein, was tolerated to the highest level. The least well tolerated were the anionic lipids, followed by lyso-PC. The others were accommodated to the extent of 20-25 mol %. Beyond a certain concentration limit, the lipid additives either triggered one or a series of phase transitions or saturated the phase and separated out as crystals, as seen with oleamide and cholesterol. The series of phases observed and their order of appearance were consistent with expectations in terms of interfacial curvature changes. The changes in phase type and microstructure have been rationalized on the basis of lipid molecular shape, interfacial curvature, and chain packing energy. The data should prove useful in the rational design of cubic phase crystallization matrices with different lipid profiles that match the needs of a greater range of membrane proteins. PMID:12496106

  1. Solution Structure of Porcine Delta Sleep-inducing Peptide Immunoreactive Peptide A Homolog of the Shortsighted Gene Product

    Microsoft Academic Search

    Gabi Seidel; Knut Adermann; Thomas Schindler; Andrzej Ejchart; Rainer Jaenicke; Wolf-Georg Forssmann; Paul Roschi

    1997-01-01

    The 77-residue delta sleep-inducing peptide immuno- reactive peptide (DIP) is a close homolog of the Drosoph- ila melanogaster shortsighted gene product. Porcine DIP (pDIP) and a peptide containing a leucine zipper- related partial sequence of pDIP, pDIP(9 - 46), was syn- thesized and studied by circular dichroism and nuclear magnetic resonance spectroscopy in combination with molecular dynamics calculations. Ultracentrifugation, size

  2. Delta sleep inducing peptide (DSIP): effect on respiration activity in rat brain mitochondria and stress protective potency under experimental hypoxia

    Microsoft Academic Search

    Elena M. Khvatova; Victor N. Samartzev; Pavel P. Zagoskin; Igor A. Prudchenko; Inessa I. Mikhaleva

    2003-01-01

    Neuromodulatory delta sleep inducing peptide (DSIP) seems to be implicated in the attenuation of stress-induced pathological metabolic disturbances in various animal species and human beings. Mitochondria, as cell organelles, are considered especially sensitive to stress conditions. In this work, the influence of DSIP and Deltaran®—a recently developed product based upon DSIP—on processes of oxidative phosphorylation and ATP production in rat

  3. Characterization, properties and multivariate functions of delta-sleep-inducing peptide (DSIP).

    PubMed

    Schoenenberger, G A

    1984-01-01

    From 1963 to 1970 the possibility of humoral transmission of delta (SWS)-EEG sleep in rabbits by, i.c.v. infusion of extracorporal dialysate from blood of the sinus confluens of donors kept asleep by electrical stimulation of the ventromedian intralaminar thalamus, has been established. From 1970 to 1977 we isolated, characterized and synthesized a nonapeptide called delta-sleep-inducing peptide (DSIP) responsible for this effect. Subsequently, intravenous administration of DSIP was shown to produce, in different animals, sleep lasting for hours. Analogs with exchanged amino acids in the sequence or shortening the peptide by one or two amino acids decreased or abolished the effect, as did breakdown products, suggesting a close structure-specificity. In contrast sleep-induction per se was found to be species specific, i.e. in cats REM-sleep was predominantly produced. I.c.v., i.v. and s.c. administration yielded, in contrast to pharmaka, a parabolic dose-response curve with different effective optima. Additionally to sleep-induction, DSIP acts upon the circadian rhythmicity of the locomotor activity and transmitter concentrations in the brain and on that of plasma proteins and cortisol levels. We then synthesized a manyfold more powerful derivative by phosphorylation of the serine in position 7 (DSIP-P). Both forms, DSIP and DSIP-P occur in human CSF. Immunoreactive DSIP-like material was found in plasma of several mammals and humans, in human urine, CSF and milk. The penetration of the blood-brain barrier by the peptide has been proven and it was shown that unweaned rats are able to take up DSIP by the intestinal tract. The half-life time for proteolytic split-off of tryptophan by brain slices and homogenates is 15 min. Endogenous immunoreactive DSIP-like material in plasma, urine and CSF was found to be bound to a larger protein (carrier ?) and thus protected from proteolysis. Immunohistochemically DSIP was shown to occur in different regions of the rat brain. The multivariate activity of the peptide was then suggested by its interaction with acute and chronic stress and with drug-effects such as morphine, d-amphetamine and barbiturates. An induction of MAO-A and RNA synthesis in the brain was observed and the brain concentration of DSIP increased during progressed hibernation. Finally, alcohol addictism produced a substantial decrease of the DSIP-concentration in the rat brain and a specific electrophysiological effect on isolated neurons of rats and rabbits was established.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6548966

  4. Effect of Delta-Sleep-Inducing Peptide on Expression of Heat Shock Protein 70 kDa in K562 Cells

    Microsoft Academic Search

    A. A. Nurbakov; I. I. Mikhaleva; A. M. Sapozhnikov

    2009-01-01

    For evaluation of the stress-protective influence of delta-sleep inducing peptide we studied its effects on the system of\\u000a heat-shock proteins in immune cells using the method of flow cytometry. The peptide affected the expression of heat-shock\\u000a protein 70 kDa in cultured human myeloleukemia K562 cells. Delta-sleep-inducing peptide reduces accumulation of intracellular\\u000a heat shock proteins 70 kDa in cells cultured under conditions of

  5. [Effect of delta-sleep inducing peptide preparation Deltaran on longevity, physiological functions, and carcinogenesis in mice].

    PubMed

    Vo?tenkov, V B; Popovich, I G; Zabezhinski?, M A; Iurova, M A; Piskunova, T A; Mikhaleva, I I

    2009-01-01

    Female SHR mice received 5-days long monthly courses of delta-sleep inducing peptide (DSIP) preparation "Deltaran" subcutaneously in dose 5 mkg/kg during all their lives. It was demonstrated, that last 10% (most aged) of mice which received Deltaran lived for 16% longer than the controls. They had significantly higher amount of vertical activity in the "open field" test, than the controls, starting from time when they were 6 months old and until their natural death. Mice of Deltaran group spent 73% more time in the open arms of elevated plus maze, and 9 times more often explored the extremities of this maze, than controls. Also Deltaran slowed the spontaneous carcinogenesis parameters. It's assumed that DSIP preparation "Deltaran" have geroprotective, anxiolytic and antitumor activity. PMID:20405733

  6. Effect of delta-sleep inducing peptide-containing preparation Deltaran on biomarkers of aging, life span and spontaneous tumor incidence in female SHR mice

    Microsoft Academic Search

    Irina G. Popovich; Boris O. Voitenkov; Vladimir N. Anisimov; Vadim T. Ivanov; Inessa I. Mikhaleva; Mark A. Zabezhinski; Irina N. Alimova; Dmitri A. Baturin; Natalia Yu. Zavarzina; Svetlana V. Rosenfeld; Anna V. Semenchenko; Anatoli I. Yashin

    2003-01-01

    From the age of 3 months until their natural deaths, female Swiss-derived SHR mice were subcutaneously injected 5 consecutive days every month with 0.1 ml of normal saline (control) or with 2.5 ?g\\/mouse (?100 ?g\\/kg) of delta-sleep inducing peptide (DSIP, Trp–Ala–Gly–Gly–Asp–Ala–Ser–Gly–Glu) as the preparation Deltaran® solved in 0.1 ml of saline. There were 54 mice in each group. The results

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

    PubMed

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

    2015-06-01

    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

  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. Effect of delta-sleep inducing peptide-containing preparation Deltaran on biomarkers of aging, life span and spontaneous tumor incidence in female SHR mice.

    PubMed

    Popovich, Irina G; Voitenkov, Boris O; Anisimov, Vladimir N; Ivanov, Vadim T; Mikhaleva, Inessa I; Zabezhinski, Mark A; Alimova, Irina N; Baturin, Dmitri A; Zavarzina, Natalia Yu; Rosenfeld, Svetlana V; Semenchenko, Anna V; Yashin, Anatoli I

    2003-06-01

    From the age of 3 months until their natural deaths, female Swiss-derived SHR mice were subcutaneously injected 5 consecutive days every month with 0.1 ml of normal saline (control) or with 2.5 microg/mouse (approximately 100 microg/kg) of delta-sleep inducing peptide (DSIP, Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) as the preparation Deltaran solved in 0.1 ml of saline. There were 54 mice in each group. The results of this study show that the treatment with Deltaran did not influence food consumption, but decreased the body weight of mice; it slowed down the age-related switching-off of estrous function; it decreased by 22.6% the frequency of chromosome aberrations in bone marrow cells; it did not influence mean life span; and it increased by 17.1% life span of the last 10% of the survivors and by 24.1% maximum life span in comparison with the control group. We also found that treatment with Deltaran significantly decreased total spontaneous tumor incidence (by 2.6-fold), mainly mammary carcinomas and leukemias in mice as compared with the control group. This is the first report on geroprotector and anticarcinogenic effect of DSIP-containing preparation Deltaran. PMID:12782416

  11. Lipid14: The Amber Lipid Force Field

    PubMed Central

    2015-01-01

    The AMBER lipid force field has been updated to create Lipid14, allowing tensionless simulation of a number of lipid types with the AMBER MD package. The modular nature of this force field allows numerous combinations of head and tail groups to create different lipid types, enabling the easy insertion of new lipid species. The Lennard-Jones and torsion parameters of both the head and tail groups have been revised and updated partial charges calculated. The force field has been validated by simulating bilayers of six different lipid types for a total of 0.5 ?s each without applying a surface tension; with favorable comparison to experiment for properties such as area per lipid, volume per lipid, bilayer thickness, NMR order parameters, scattering data, and lipid lateral diffusion. As the derivation of this force field is consistent with the AMBER development philosophy, Lipid14 is compatible with the AMBER protein, nucleic acid, carbohydrate, and small molecule force fields. PMID:24803855

  12. 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

  13. CARRIER MEDIATED LIPID TRANSPORT

    Microsoft Academic Search

    Scott D. Covey

    2003-01-01

    Lipids are essential molecules for cellular function; they are required for energy production, membrane structure, and can serve as signaling molecules. Normal metabolism requires cellular uptake and efflux as well as intercellular transport of lipids. Disruption of these events can lead to pathological processes like obesity and atherosclerosis. Transport of lipids between tissues involves moving hydrophobic species through a polar

  14. Lipids of silkworm cocoons

    Microsoft Academic Search

    I. Tolibaev; Sh. R. Mad'yarov; A. I. Glushenkova

    1995-01-01

    The lipid complex of silkworm cocoons had been investigated. The qualitative and quantitative compositions of the total neutral lipids and glyco- and phospholipids have been determined. Considerable differences have been noted in the amounts of individual fatty acids in the neutral lipids and the phospholipids.

  15. Solid Lipid Nanoparticles

    Microsoft Academic Search

    Anne Saupe; Thomas Rades

    In the last decade of the last century, solid lipid nanoparticles (SLN) have been introduced to the literature as a novel carrier system for cosmetic active ingredients and pharmaceutical drugs. SLN consist of biodegradable physiological lipids or lipidic substances and stabilisers which are generally recognised as safe (GRAS) or have a regulatory accepted status. Compared to other delivery systems such

  16. Lipid signalling in disease

    Microsoft Academic Search

    Roger Schneiter; Matthias P. Wymann

    2008-01-01

    Signalling lipids such as eicosanoids, phosphoinositides, sphingolipids and fatty acids control important cellular processes, including cell proliferation, apoptosis, metabolism and migration. Extracellular signals from cytokines, growth factors and nutrients control the activity of a key set of lipid-modifying enzymes: phospholipases, prostaglandin synthase, 5-lipoxygenase, phosphoinositide 3-kinase, sphingosine kinase and sphingomyelinase. These enzymes and their downstream targets constitute a complex lipid signalling

  17. Lipid Signaling in Tumorigenesis

    PubMed Central

    Liu, Renyan; Huang, Ying

    2015-01-01

    Lipids are important cellular building blocks and components of signaling cascades. Deregulation of lipid metabolism or signaling is frequently linked to a variety of human diseases such as diabetes, cardiovascular diseases, and cancer. It is widely believed that lipid molecules or their metabolic products are involved in tumorigenic inflammation and thus, lipids are implicated as significant contributors or even primary triggers of tumorigenesis. Lipids are believed to directly or indirectly activate growth promoting signals such as those involving LPA, insulin, IGF-1 and EGF to promote cancer cell growth. Cellular levels of certain lipids, including sphingosine-1-phosphate and ceramide, maintain a delicate balance between cell death and survival and alterations in their levels lead to unfavorable consequences including tumorigenesis. This article provides an overview of current knowledge that implicates lipids in tumorigenesis and explores the potential mechanisms that support a positive link between obesity and cancer. PMID:25741396

  18. 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

  19. Lipids of Mentha spicata

    Microsoft Academic Search

    T. V. Khomova; S. D. Gusakova; A. Nigmatullaev

    1997-01-01

    The levels of lipids, pigments, and essential oil and the lipid and fatty acid compositions of individual organs of freshly gatheredMentha spicata plants have been established. It has been found that the organs studied have a complex qualitative composition of the extractive substances but differ in their levels of individual groups of substances and components.

  20. Lipid signalling in disease.

    PubMed

    Wymann, Matthias P; Schneiter, Roger

    2008-02-01

    Signalling lipids such as eicosanoids, phosphoinositides, sphingolipids and fatty acids control important cellular processes, including cell proliferation, apoptosis, metabolism and migration. Extracellular signals from cytokines, growth factors and nutrients control the activity of a key set of lipid-modifying enzymes: phospholipases, prostaglandin synthase, 5-lipoxygenase, phosphoinositide 3-kinase, sphingosine kinase and sphingomyelinase. These enzymes and their downstream targets constitute a complex lipid signalling network with multiple nodes of interaction and cross-regulation. Imbalances in this network contribute to the pathogenesis of human disease. Although the function of a particular signalling lipid is traditionally studied in isolation, this review attempts a more integrated overview of the key role of these signalling lipids in inflammation, cancer and metabolic disease, and discusses emerging strategies for therapeutic intervention. PMID:18216772

  1. Lipids of Archaeal Viruses

    PubMed Central

    Roine, Elina; Bamford, Dennis H.

    2012-01-01

    Archaeal viruses represent one of the least known territory of the viral universe and even less is known about their lipids. Based on the current knowledge, however, it seems that, as in other viruses, archaeal viral lipids are mostly incorporated into membranes that reside either as outer envelopes or membranes inside an icosahedral capsid. Mechanisms for the membrane acquisition seem to be similar to those of viruses infecting other host organisms. There are indications that also some proteins of archaeal viruses are lipid modified. Further studies on the characterization of lipids in archaeal viruses as well as on their role in virion assembly and infectivity require not only highly purified viral material but also, for example, constant evaluation of the adaptability of emerging technologies for their analysis. Biological membranes contain proteins and membranes of archaeal viruses are not an exception. Archaeal viruses as relatively simple systems can be used as excellent tools for studying the lipid protein interactions in archaeal membranes. PMID:23049284

  2. Cytarabine Lipid Complex Injection

    MedlinePLUS

    ... type of cancer in the covering of the spinal cord and brain). Cytarabine lipid complex is in a class of medications called antimetabolites. It works by slowing or stopping the growth of cancer cells in your body.

  3. Lipid Storage Diseases

    MedlinePLUS

    ... of the lipid storage disorders, although Gaucher and Fabry diseases have highly effective enzyme replacement therapies. There is ... from infection or progressive neurological loss. Children with Fabry disease often die prematurely of complications from heart disease, ...

  4. Focus Issue: Signaling Lipids

    NSDL National Science Digital Library

    Nancy R. Gough (American Association for the Advancement of Science; Science's STKE REV)

    2006-02-07

    Membranes are dynamic and specific contributors to cell signaling. Cellular membranes play a key structural role in creating sites for the formation of signaling complexes. Changes in membrane phospholipids can regulate the activity of transmembrane and peripheral membrane proteins. Modification of membrane lipids can result in formation of dynamic signaling molecules. Science's STKE highlights new insights into the roles that lipids and membranes play in cell signaling.

  5. Lipids in human milk

    Microsoft Academic Search

    Robert G. Jensen

    1999-01-01

    I have reviewed recent (March 1995–December 1997) papers on human milk lipids including many on fatty acid (FA) composition.\\u000a The effects of maternal diets on the profiles are apparent. However, more data on the composition of milk lipids are needed.\\u000a It is noteworthy that so few papers on milk FA composition have reported analyses using high-resolution gas-liquid chromatography\\u000a columns. Two

  6. Sleep-Induced Changes in Associative Memory

    Microsoft Academic Search

    Robert Stickgold; Laurie Scott; Cynthia Rittenhouse; J. Allan Hobson

    1999-01-01

    The notion that dreaming might alter the strength of associative links in memory was first proposed almost 200 years ago. But no strong evidence of such altered associative links has been obtained. Semantic priming can be used to quantify the strength of associative links between pairs of words; it is thought to measure the automatic spread of activation from a

  7. 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

  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

    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

  9. 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

  10. Lipid-lowering drugs

    PubMed Central

    Pahan, K.

    2007-01-01

    Although a change in life-style is often the method of first choice for lipid lowering, lipid-lowering drugs, in general, help to control elevated levels of different forms of lipids in patients with hyperlipidemia. While one group of drugs, statins, lowers cholesterol, the other group, fibrates, is known to take care of fatty acids and triglycerides. In addition, other drugs, such as ezetimibe, colesevelam, torcetrapib, avasimibe, implitapide, and niacin are also being considered to manage hyperlipidemia. As lipids are very critical for cardiovascular diseases, these drugs reduce fatal and nonfatal cardiovascular abnormalities in the general population. However, a number of recent studies indicate that apart from their lipid-lowering activities, statins and fibrates exhibit multiple functions to modulate intracellular signaling pathways, inhibit inflammation, suppress the production of reactive oxygen species, and modulate T cell activity. Therefore, nowadays, these drugs are being considered as possible therapeutics for several forms of human disorders including cancer, autoimmunity, inflammation, and neurodegeneration. Here I discuss these applications in the light of newly discovered modes of action of these drugs. PMID:16568248

  11. Nuclear Lipid Signaling

    NSDL National Science Digital Library

    Robin F. Irvine (University of Cambridge; Department of Pharmacology REV)

    2002-09-17

    The eukaryotic nucleus is surrounded by a double membrane that can be regarded as a specialized part of the endoplasmic reticulum, so it is no surprise that lipids are present in nuclei, and that these can change under some conditions. However, what is surprising is that if the nuclear membrane is removed by detergents, there remains a considerable amount of lipid and lipid-synthesizing and metabolizing enzymes. These enzymes are undoubtedly intranuclear, and they cannot be discounted as arising from contamination with other cellular fractions. The best characterized of these enzymes are the components of a nuclear polyphosphoinositide cycle that generates phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2]. This PtdIns(4,5)P2 can in turn be hydrolyzed to diacylglycerol (DAG) by a phospholipase C (PI-PLC) that is regulated separately from the "classic" plasma membrane PI-PLC. This nuclear DAG can recruit protein kinase C from the cytoplasm to the nucleus to phosphorylate substrates, most of which are still unidentified. However, that cycle is only the tip of the iceberg, and more lipid signaling pathways and players are being implicated as existing within the nucleus. This is a large and confusing literature. This review focuses on the main issues and critically assesses the best evidence for what is and is not truly nuclear lipid signaling, and for what such signaling may or may not do.

  12. Nuclear Lipid Signaling

    NSDL National Science Digital Library

    Robin Irvine (University of Cambridge; Department of Pharmacology REV)

    2000-09-05

    The eukaryotic nucleus is surrounded by a double membrane that can be regarded as a part of the endoplasmic reticulum, albeit a specialized part, so it is no particular surprise that lipids are present in nuclei, and that these can change under some conditions. However, what is surprising to many people is that if the nuclear membrane is removed by detergents, there is still a considerable amount of lipid left, and a large number of lipid-synthesizing and metabolizing enzymes. These enzymes are undoubtedly intranuclear, and cannot be discounted as arising from contamination with other cellular fractions. The best characterized of these enzymes are the components of a nuclear polyphosphoinositide cycle that generates phosphatidylinositol-4,5-bisphosphate [PIP2 or PtdIns(4,5)P2]. This PIP2 can in turn be hydrolyzed to diacylglycerol by a phospholipase C (PI-PLC) that is regulated separately from the "classic" plasma membrane PI-PLC. This nuclear diacylglycerol can recruit protein kinase C to the nucleus to phosphorylate substrates (mostly) as yet unidentified. However, that cycle is only the tip of the iceberg, and more and more lipid signaling pathways and players are being implicated as existing within the nucleus. This is a large and confusing literature. This review focuses on the main issues critically assesses the best evidence for what is and is not truly nuclear lipid signaling, and for what such signaling may or may not do.

  13. 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.

  14. Lipid management in ramadan.

    PubMed

    Slim, Ines; Ach, Koussay; Chaieb, Larbi

    2015-05-01

    During Ramadan fast, Muslims must refrain from smoking, eating, drinking, having sexual activity, and consuming oral medications from sunrise to sunset. It has been previously shown that Ramadan fasting induces favourable changes on metabolic parameters, reduces oxidative stress and inflammation and promotes cardiovascular benefits. Although ill people are exempted from fasting, most patients with chronic diseases are keen on performing this Islamic-ritual. During recent years, Risk stratification and treatment adjustment during Ramadan are well known and structured in several guidelines for patients with diabetes mellitus. Data related to the effect of Ramadan fast on lipid profiles are less known and several controversies have been reported. Here, we focus on lipid profile and lipid management during Ramadan taking into account comorbidities and cardiovascular risk. PMID:26013790

  15. Lipids of Viburnum opulus seeds

    Microsoft Academic Search

    S. G. Yunusova; E. G. Zinurova; M. S. Yunusov; E. G. Galkin; A. R. Karimova

    1998-01-01

    Lipid components of the seeds ofViburnum opulus (Caprifoliaceae family) were investigated. The neutral lipids consist of eight classes, the glycolipids consist of three classes, and the\\u000a phospholipids contain seven classes. The fatty-acid contents of all of the acyl-containing lipids were determined. The 18?2\\u000a fatty acid is the main component of all the lipid fractions. The content of saturated acids is

  16. Lipid rafts and signal transduction

    Microsoft Academic Search

    Kai Simons; Derek Toomre

    2000-01-01

    Signal transduction is initiated by complex protein–protein interactions between ligands, receptors and kinases, to name only a few. It is now becoming clear that lipid micro-environments on the cell surface — known as lipid rafts — also take part in this process. Lipid rafts containing a given set of proteins can change their size and composition in response to intra-

  17. Lipids in cheese

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lipids are present in cheese at levels above 20 percent and are analyzed by several techniques. Scanning electron microscopy and confocal laser scanning microscopy are used to examine the microstructure, gas chromatography is employed to look at fatty acid composition, and differential scanning cal...

  18. Structure of lipid bilayers

    PubMed Central

    Nagle, John F.; Tristram-Nagle, Stephanie

    2009-01-01

    The quantitative experimental uncertainty in the structure of fully hydrated, biologically relevant, fluid (L?) phase lipid bilayers has been too large to provide a firm base for applications or for comparison with simulations. Many structural methods are reviewed including modern liquid crystallography of lipid bilayers that deals with the fully developed undulation fluctuations that occur in the L? phase. These fluctuations degrade the higher order diffraction data in a way that, if unrecognized, leads to erroneous conclusions regarding bilayer structure. Diffraction measurements at high instrumental resolution provide a measure of these fluctuations. In addition to providing better structural determination, this opens a new window on interactions between bilayers, so the experimental determination of interbilayer interaction parameters is reviewed briefly. We introduce a new structural correction based on fluctuations that has not been included in any previous studies. Updated measurements, such as for the area compressibility modulus, are used to provide adjustments to many of the literature values of structural quantities. Since the gel (L??) phase is valuable as a stepping stone for obtaining fluid phase results, a brief review is given of the lower temperature phases. The uncertainty in structural results for lipid bilayers is being reduced and best current values are provided for bilayers of five lipids. PMID:11063882

  19. Lanolin-derived lipid mixtures mimic closely the lipid composition and organization of vernix caseosa lipids

    Microsoft Academic Search

    Robert Rissmann; Marion H. M. Oudshoorn; Elise Kocks; Wim E. Hennink; Maria Ponec; Joke A. Bouwstra

    2008-01-01

    The aim of the present study was to use semi-synthetic lipid mixtures to mimic the complex lipid composition, organization and thermotropic behaviour of vernix caseosa (VC) lipids. As VC shows multiple protecting and barrier supporting properties before and after birth, it is suggested that a VC substitute could be an innovative barrier cream for barrier deficient skin. Lanolin was selected

  20. Lipid composition of perilla seed

    Microsoft Academic Search

    Hyo-Sun Shin; Sung-Whan Kim

    1994-01-01

    The composition of lipids and oil characteristics from perilla [Perilla frutescens (L.) Britt.] seed cultivars are reported. Total lipid contents of the five perilla seed cultivars ranged from 38.6 to 47.8%\\u000a on a dry weight basis. The lipids consisted of 91.2–93.9% neutral lipids, 3.9–5.8% glycolipids and 2.0–3.0% phospholipids.\\u000a Neutral lipids consisted mostly of triacylglycerols (88.1–91.0%) and small amounts of sterol

  1. Dysregulated lipid metabolism in cancer

    PubMed Central

    Zhang, Feng; Du, Guangwei

    2012-01-01

    Alteration of lipid metabolism has been increasingly recognized as a hallmark of cancer cells. The changes of expression and activity of lipid metabolizing enzymes are directly regulated by the activity of oncogenic signals. The dependence of tumor cells on the dysregulated lipid metabolism suggests that proteins involved in this process are excellent chemotherapeutic targets for cancer treatment. There are currently several drugs under development or in clinical trials that are based on specifically targeting the altered lipid metabolic pathways in cancer cells. Further understanding of dysregulated lipid metabolism and its associated signaling pathways will help us to better design efficient cancer therapeutic strategy. PMID:22937213

  2. Mannosylerythritol lipids: a review

    Microsoft Academic Search

    Joseph Irudayaraj Arutchelvi; Sumit Bhaduri; Parasu Veera Uppara; Mukesh Doble

    2008-01-01

    Mannosylerythritol lipids (MELs) are surface active compounds that belong to the glycolipid class of biosurfactants (BSs).\\u000a MELs are produced by Pseudozyma sp. as a major component while Ustilago sp. produces them as a minor component. Although MELs have been known for over five decades, they recently regained attention\\u000a due to their environmental compatibility, mild production conditions, structural diversity, self-assembling properties

  3. Lipid peroxidation and tissue damage.

    PubMed

    Mylonas, C; Kouretas, D

    1999-01-01

    In recent years it has become apparent that the oxidation of lipids, or lipid peroxidation, is a crucial step in the pathogenesis of several disease states in adult and infant patients. Lipid peroxidation is a process generated naturally in small amounts in the body, mainly by the effect of several reactive oxygen species (hydroxyl radical, hydrogen peroxide etc.). It can also be generated by the action of several phagocytes. These reactive oxygen species readily attack the polyunsaturated fatty acids of the fatty acid membrane, initiating a self-propagating chain reaction. The destruction of membrane lipids and the end-products of such lipid peroxidation reactions are especially dangerous for the viability of cells, even tissues. Enzymatic (catalase, superoxide dismutasse) and nonenzymatic (vitamins A and E) natural antioxidant defence mechanisms exist; however, these mechanisms may be overcome, causing lipid peroxidation to take place. Since lipid peroxidation is a self-propagating chain-reaction, the initial oxidation of only a few lipid molecules can result in significant tissue damage. Despite extensive research in the field of lipid peroxidation it has not yet been precisely determined if it is the cause or an effect of several pathological conditions. Lipid peroxidation has been implicated in disease states such as atherosclerosis, IBD, ROP, BPD, asthma, Parkinson's disease, kidney damage, preeclampsia and others. PMID:10459507

  4. Lipid Simulations: A Perspective on Lipids in Action

    PubMed Central

    Vattulainen, Ilpo; Rog, Tomasz

    2011-01-01

    In this article, we provide an overview of lipid simulations, describing how a computer can be used as a laboratory for lipid research. We briefly discuss the methodology of lipid simulations followed by a number of topical applications that show the benefit of computer modeling for complementing experiments. In particular, we show examples of cases in which simulations have made predictions of novel phenomena that have later been confirmed by experimental studies. Overall, the applications discussed in this article focus on the most recent state of the art and aim to provide a perspective of where the field of lipid simulations stands at the moment. PMID:21441592

  5. ANALYSIS OF POLAR LIPIDS FROM OAT GROATS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oats are a rich source of polar lipids and oat polar lipids are being applied to some unique applications. However, many characteristics of polar oat lipid composition have not yet been characterized with modern methodology. Our objective was to identify constitutive lipids of the polar lipid fracti...

  6. Lipid metabolism in mitochondrial membranes.

    PubMed

    Mayr, Johannes A

    2015-01-01

    Mitochondrial membranes have a unique lipid composition necessary for proper shape and function of the organelle. Mitochondrial lipid metabolism involves biosynthesis of the phospholipids phosphatidylethanolamine, cardiolipin and phosphatidylglycerol, the latter is a precursor of the late endosomal lipid bis(monoacylglycero)phosphate. It also includes mitochondrial fatty acid synthesis necessary for the formation of the lipid cofactor lipoic acid. Furthermore the synthesis of coenzyme Q takes place in mitochondria as well as essential parts of the steroid and vitamin D metabolism. Lipid transport and remodelling, which are necessary for tailoring and maintaining specific membrane properties, are just partially unravelled. Mitochondrial lipids are involved in organelle maintenance, fission and fusion, mitophagy and cytochrome c-mediated apoptosis. Mutations in TAZ, SERAC1 and AGK affect mitochondrial phospholipid metabolism and cause Barth syndrome, MEGDEL and Sengers syndrome, respectively. In these disorders an abnormal mitochondrial energy metabolism was found, which seems to be due to disturbed protein-lipid interactions, affecting especially enzymes of the oxidative phosphorylation. Since a growing number of enzymes and transport processes are recognised as parts of the mitochondrial lipid metabolism, a further increase of lipid-related disorders can be expected. PMID:25082432

  7. Ocular lipid deposition and hyperlipoproteinaemia.

    PubMed

    Crispin, Sheila

    2002-03-01

    In all species there are potential ocular manifestations when circulating lipoproteins are raised and these may be transient or permanent Many factors, both systemic and local, influence lipid influx and accumulation (progression) and lipid mobilisation and efflux (regression). In both humans and animals some types of lipid deposition will regress if the local and systemic factors involved in pathogenesis can be modified. There are inescapable parallels with the same phenomena in other tissues.Three types of corneal lipid deposition have been linked with hyperlipoproteinaemia. In corneal arcus, lipid is deposited preferentially in the warmest part of the cornea initially and, in people, the lipid remains almost exclusively extracellular. In animals, corneal arcus is associated with initial extracellular lipid deposition followed by the appearance of intracellular lipid and vascularisation, so that established corneal arcus tends to become more typical of lipid keratopathy. In humans, hyperlipoproteinaemia may be an associated systemic factor and early onset corneal arcus is a recognised feature of certain primary hyperlipoproteinaemias and their secondary phenotypes. In dogs, corneal arcus is always associated with hyperlipoproteinaemia. Corneal vascularisation is a ubiquitous feature of lipid keratopathy in all species and both necrotic fibroblasts and foam cells are common in progressive lesions. The extent and position of lipid deposition and the evolution of lipid keratopathy can be related to local ocular disease and circulating lipids and lipoproteins. Many aspects of the pathogenesis of lipid keratopathy are similar to those of atherogenesis. Hyperlipoproteinaemia, especially hypercholesterolaemia is the commonest systemic abnormality. In crystalline stromal dystrophy (Schnyder's crystalline stromal dystrophy) of the cornea there is no inflammatory element and no vascularisation. The dystrophy is associated with accumulation of lipid within the corneal fibroblasts, but typical foam cells are absent, the crystalline opacity involves the coolest part of the cornea, correlates with local fibroblast death, and is always bilateral. Hyperlipoproteinaemia, may be present, but this is not universally so.The objective of this paper is to evaluate the factors that may influence ocular involvement in hyperlipoproteinaemia. A comparative approach, utilising information available from studies of both ocular and non-ocular tissues, aids elucidation of the complex pathogenesis. PMID:12062534

  8. 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…

  9. Association of lipid metabolism with ovarian cancer

    PubMed Central

    Tania, M.; Khan, M.A.; Song, Y.

    2010-01-01

    Defects in lipid metabolism have been found to be linked to several diseases, among which atherosclerosis, hypertension, obesity, and diabetes are the most important. Although cancer is chiefly a genetic disease, dietary lipid intake and metabolism are related to some cancer risks, including the risk for ovarian cancer. Higher intake of dietary lipids, systemic lipid metabolism malfunction, and abnormal serum lipid levels are somehow related to ovarian cancer. Overexpression of some lipid metabolic enzymes are also found in ovarian cancer. In this review article, we summarize the relationships between lipid intake, lipid metabolism, and ovarian cancer. PMID:20975872

  10. Modeling Lipid Membranes

    NASA Astrophysics Data System (ADS)

    Chipot, Christophe; Klein, Michael L.; Tarek, Mounir

    Membranes consist of an assembly of a wide variety of lipids [1], proteins and carbohydrates that self-organize to assume a host of biological functions in the cell machinery, like the passive and active transport of matter, the capture and storage of energy, the control of the ionic balance, or the intercellular recognition and signalling. In essence, membranes act as walls that delimit the interior of the cell from the outside environment, preventing the free translocation of small molecules from one side to the other. At an atomic level, knowledge of both the structure and the dynamics of membranes remains to a large extent fragmentary, on account of the remarkable fluidity of these systems under physiological conditions. As a result, the amount of experimental information that can be interpreted directly in terms of positions and motions is still rather limited.

  11. Renal lipid metabolism and lipotoxicity

    PubMed Central

    Bobulescu, Ion Alexandru

    2011-01-01

    Purpose of review Lipid accumulation in nonadipose tissues is increasingly recognized to contribute to organ injury through a process termed lipotoxicity, but whether this process occurs in the kidney is still uncertain. This article briefly summarizes the normal role of lipids in renal physiology and the current evidence linking excess lipids and lipotoxicity to renal dysfunction. Recent findings Evidence suggesting that renal lipid accumulation and lipotoxicity may lead to kidney dysfunction has mounted significantly over recent years. Abnormal renal lipid content has been described in a number of animal models and has been successfully manipulated using pharmacologic or genetic strategies. There is some heterogeneity among studies with regard to the mechanisms, consequences, and localization of lipid accumulation in the kidney, explainable at least in part by inherent differences between animal models. The relevance of these findings for human pathophysiology remains to be established. Summary Current knowledge on renal lipid physiology and pathophysiology is insufficient, but provides a strong foundation and incentive for further exploration. The future holds significant challenges in this area, especially with regard to applicability of research findings to the human kidney in vivo, but also the opportunity to transform our understanding of an array of kidney disorders. PMID:20489613

  12. 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.

  13. Lipid digestion and effects of diets rich in lipids on carbohydrate and nitrogen digestion. A review *

    E-print Network

    Boyer, Edmond

    Lipid digestion and effects of diets rich in lipids on carbohydrate and nitrogen digestion-Genčs-Champanelle, France This review deals with ruminal metabolism and intestinal digestion of lipids, and with the conse- quences of lipid supplementation on carbohy- drate and nitrogen digestion. Ruminal hydrolysis of lipids

  14. 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

  15. Electronic polymers in lipid membranes.

    PubMed

    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

  16. Dynamic Heterogeneity in Lipid Structures

    NASA Astrophysics Data System (ADS)

    Othon, Christina; Dadashvand, Neda

    2015-03-01

    We have characterized the temperature and pressure dependent scaling of dynamic heterogeneity in a homogenous liquid phase of a lipid monolayer using time-resolved fluorescence anisotropy (TRFA) microscopy. Rotational diffusion is far more sensitive to highly correlated motions than translational diffusion due to the enhanced influence of nearest neighbor interactions. Highly correlated motion results in regions of high-density, low mobility lipids, and low-density, high mobility lipids; and are observed as the bimodal distribution of rotational correlation times. For biological lipid membranes the presence of highly correlated motion will greatly influence the rates of protein sorting and self-assembly, as particles suspended in the fluid can become kinetically trapped. Rotational diffusion timescales (~ ns) are far shorter than the lifetime of dynamic clusters and lipid raft-like structures (~ 10 ?s), and thus the distribution of rotational correlation times can provide critical insight into the presence of these structures. We have characterized rotational dynamic distributions for a variety of phosphocholine moieties, and found dynamics consistent with highly correlated motion. Using the proximity to the phase transition, and the scaling of the temperature dependence of the heterogeneity we apply theoretical models developed for other condensed matter systems help us define limits on the size and lifetime of dynamic clusters in lipid structures. corresponding author

  17. Nanoparticle-lipid bilayer interactions studied with lipid bilayer arrays.

    PubMed

    Lu, Bin; Smith, Tyler; Schmidt, Jacob J

    2015-04-24

    The widespread environmental presence and commercial use of nanoparticles have raised significant health concerns as a result of many in vitro and in vivo assays indicating toxicity of a wide range of nanoparticle species. Many of these assays have identified the ability of nanoparticles to damage cell membranes. These interactions can be studied in detail using artificial lipid bilayers, which can provide insight into the nature of the particle-membrane interaction through variation of membrane and solution properties not possible with cell-based assays. However, the scope of these studies can be limited because of the low throughput characteristic of lipid bilayer platforms. We have recently described an easy to use, parallel lipid bilayer platform which we have used to electrically investigate the activity of 60 nm diameter amine and carboxyl modified polystyrene nanoparticles (NH2-NP and COOH-NP) with over 1000 lipid bilayers while varying lipid composition, bilayer charge, ionic strength, pH, voltage, serum, particle concentration, and particle charge. Our results confirm recent studies finding activity of NH2-NP but not COOH-NP. Detailed analysis shows that NH2-NP formed pores 0.3-2.3 nm in radius, dependent on bilayer and solution composition. These interactions appear to be electrostatic, as they are regulated by NH2-NP surface charge, solution ionic strength, and bilayer charge. The ability to rapidly measure a large number of nanoparticle and membrane parameters indicates strong potential of this bilayer array platform for additional nanoparticle bilayer studies. PMID:25853986

  18. 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

  19. Lipid metabolism in prostate cancer

    PubMed Central

    Wu, Xinyu; Daniels, Garrett; Lee, Peng; Monaco, Marie E

    2014-01-01

    The malignant transformation of cells requires adaptations across multiple metabolic processes to satisfy the energy required for their increased rate of proliferation. Dysregulation of lipid metabolism has been a hallmark of the malignant phenotype; increased lipid accumulation secondary to changes in the levels of a variety of lipid metabolic enzymes has been documented in a variety of tumors, including prostate. Alterations in prostate lipid metabolism include upregulation of several lipogenic enzymes as well as of enzymes that function to oxidize fatty acids as an energy source. Cholesterol metabolism and phospholipid metabolism are also affected. With respect to lipogenesis, most studies have concentrated on increased expression and activity ofthe de novo fatty acid synthesis enzyme, fatty acid synthase (FASN), with suggestions that FASN might function as an oncogene. A central role for fatty acid oxidation in supplying energy to the prostate cancer cell is supported by the observation that the peroxisomal enzyme, ?-methylacyl-CoA racemase (AMACR), which facilitates the transformation of branched chain fatty acids to a form suitable for ?-oxidation, is highly overexpressed in prostate cancer compared with normal prostate. Exploitation of the alterations in lipid metabolic pathways in prostate cancer could result in the development of new therapeutic modalities as well as provide candidates for new prognostic and predictive biomarkers. AMACR has already proven to be a valuable biomarker in distinguishing normal from malignant prostate tissue, and is used routinely in clinical practice. PMID:25374912

  20. 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

  1. Chemical and structural investigation of lipid nanoparticles: drug-lipid interaction and molecular distribution

    NASA Astrophysics Data System (ADS)

    Anantachaisilp, Suranan; Meejoo Smith, Siwaporn; Treetong, Alongkot; Pratontep, Sirapat; Puttipipatkhachorn, Satit; Rungsardthong Ruktanonchai, Uracha

    2010-03-01

    Lipid nanoparticles are a promising alternative to existing carriers in chemical or drug delivery systems. A key challenge is to determine how chemicals are incorporated and distributed inside nanoparticles, which assists in controlling chemical retention and release characteristics. This study reports the chemical and structural investigation of ?-oryzanol loading inside a model lipid nanoparticle drug delivery system composed of cetyl palmitate as solid lipid and Miglyol 812® as liquid lipid. The lipid nanoparticles were prepared by high pressure homogenization at varying liquid lipid content, in comparison with the ?-oryzanol free systems. The size of the lipid nanoparticles, as measured by the photon correlation spectroscopy, was found to decrease with increased liquid lipid content from 200 to 160 nm. High-resolution proton nuclear magnetic resonance (1H-NMR) measurements of the medium chain triglyceride of the liquid lipid has confirmed successful incorporation of the liquid lipid in the lipid nanoparticles. Differential scanning calorimetric and powder x-ray diffraction measurements provide complementary results to the 1H-NMR, whereby the crystallinity of the lipid nanoparticles diminishes with an increase in the liquid lipid content. For the distribution of ?-oryzanol inside the lipid nanoparticles, the 1H-NMR revealed that the chemical shifts of the liquid lipid in ?-oryzanol loaded systems were found at rather higher field than those in ?-oryzanol free systems, suggesting incorporation of ?-oryzanol in the liquid lipid. In addition, the phase-separated structure was observed by atomic force microscopy for lipid nanoparticles with 0% liquid lipid, but not for lipid nanoparticles with 5 and 10% liquid lipid. Raman spectroscopic and mapping measurements further revealed preferential incorporation of ?-oryzanol in the liquid part rather than the solid part of in the lipid nanoparticles. Simple models representing the distribution of ?-oryzanol and lipids (solid and liquid) inside the lipid nanoparticle systems are proposed.

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

    NSDL National Science Digital Library

    Kathleen M. Eyster (Sanford School of Medicine, University of South Dakota Division of Basic Biomedical Sciences)

    2007-03-01

    This review seeks to explore the magnitude and diversity of the roles of the cell membrane and lipids in signal transduction and to highlight the interrelatedness of families of lipid mediators in signal transduction

  3. Crystallization modifiers in lipid systems.

    PubMed

    Ribeiro, Ana Paula Badan; Masuchi, Monise Helen; Miyasaki, Eriksen Koji; Domingues, Maria Aliciane Fontenele; Stroppa, Valter Luís Zuliani; de Oliveira, Glazieli Marangoni; Kieckbusch, Theo Guenter

    2015-07-01

    Crystallization of fats is a determinant physical event affecting the structure and properties of fat-based products. The stability of these processed foods is regulated by changes in the physical state of fats and alterations in their crystallization behavior. Problems like polymorphic transitions, oil migration, fat bloom development, slow crystallization and formation of crystalline aggregates stand out. The change of the crystallization behavior of lipid systems has been a strategic issue for the processing of foods, aiming at taylor made products, reducing costs, improving quality, and increasing the applicability and stability of different industrial fats. In this connection, advances in understanding the complex mechanisms that govern fat crystallization led to the development of strategies in order to modulate the conventional processes of fat structuration, based on the use of crystallization modifiers. Different components have been evaluated, such as specific triacyglycerols, partial glycerides (monoacylglycerols and diacylglycerols), free fatty acids, phospholipids and emulsifiers. The knowledge and expertise on the influence of these specific additives or minor lipids on the crystallization behavior of fat systems represents a focus of current interest for the industrial processing of oils and fats. This article presents a comprehensive review on the use of crystallization modifiers in lipid systems, especially for palm oil, cocoa butter and general purpose fats, highlighting: i) the removal, addition or fractionation of minor lipids in fat bases; ii) the use of nucleating agents to modify the crystallization process; iii) control of crystallization in lipid bases by using emulsifiers. The addition of these components into lipid systems is discussed in relation to the phenomena of nucleation, crystal growth, morphology, thermal behavior and polymorphism, with the intention of providing the reader with a complete panorama of the associated mechanisms with crystallization of fats and oils. PMID:26139862

  4. Lipid signals and insulin resistance.

    PubMed

    Zhang, Chongben; Klett, Eric L; Coleman, Rosalind A

    2013-12-01

    The metabolic syndrome, a cluster of metabolic derangements that include obesity, glucose intolerance, dyslipidemia and hypertension, is a major risk factor for cardiovascular disease. Insulin resistance has been proposed to be the common feature that links obesity to the metabolic syndrome, but the mechanism remains obscure. Although the excess content of triacylglycerol in muscle and liver is highly associated with insulin resistance in these tissues, triacylglycerol itself is not causal but merely a marker. Thus, attention has turned to the accumulation of cellular lipids known to have signaling roles. This review will discuss recent progress in understanding how glycerolipids and related lipid intermediates may impair insulin signaling. PMID:24533033

  5. Lipid signals and insulin resistance

    PubMed Central

    Zhang, Chongben; Klett, Eric L; Coleman, Rosalind A

    2014-01-01

    The metabolic syndrome, a cluster of metabolic derangements that include obesity, glucose intolerance, dyslipidemia and hypertension, is a major risk factor for cardiovascular disease. Insulin resistance has been proposed to be the common feature that links obesity to the metabolic syndrome, but the mechanism remains obscure. Although the excess content of triacylglycerol in muscle and liver is highly associated with insulin resistance in these tissues, triacylglycerol itself is not causal but merely a marker. Thus, attention has turned to the accumulation of cellular lipids known to have signaling roles. This review will discuss recent progress in understanding how glycerolipids and related lipid intermediates may impair insulin signaling. PMID:24533033

  6. 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.

  7. A new lipid anchor for sparsely tethered bilayer lipid membranes.

    PubMed

    Heinrich, Frank; Ng, Tiffany; Vanderah, David J; Shekhar, Prabhanshu; Mihailescu, Mihaela; Nanda, Hirsh; Lösche, Mathias

    2009-04-01

    Mixed self-assembled monolayers (SAMs) of beta-mercaptoethanol and the new synthetic lipid 1,2-dipalmityl-3-[w-mercaptonona(ethylene oxide)] glycerol (FC 16) were investigated for their ability to form sparsely tethered bilayer lipid membranes (stBLMs) completed with various phospholipids. We investigated the structural and functional properties of FC16-based stBLMs and compared these to stBLMs prepared using a previously characterized synthetic lipid, 1,2-dimyristyl-3-[omega-mercaptohexa(ethylene oxide)] glycerol (WC14). FC16-based stBLMs show increased resistivity to ion transfer and an increase in the submembrane space of approximately 0.5 nm. Importantly, FC16-based stBLMs formed well-defined, complete bilayers with charged phospholipids such as 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG). In these, POPG incorporates into the outer monolayer leaflet in the same ratio as in the immersion solution but is excluded from the inner leaflet. In all cases that we have investigated thus far, the area densities of the lipids within the bilayers were on average close to those in free bilayer membranes. For charged phospholipids, FC16 appears to provide a distinct advantage over WC14 for the formation of well-defined stBLMs. PMID:19714901

  8. Triglyceride Blisters in Lipid Bilayers: Implications for Lipid Droplet Biogenesis and the Mobile Lipid Signal in Cancer Cell Membranes

    Microsoft Academic Search

    Himanshu Khandelia; Lars Duelund; Kirsi I. Pakkanen; John H. Ipsen; Darren R. Flower

    2010-01-01

    Triglycerides have a limited solubility, around 3%, in phosphatidylcholine lipid bilayers. Using millisecond-scale course grained molecular dynamics simulations, we show that the model lipid bilayer can accommodate a higher concentration of triolein (TO) than earlier anticipated, by sequestering triolein molecules to the bilayer center in the form of a disordered, isotropic, mobile neutral lipid aggregate, at least 17 nm in

  9. Nanoparticle-lipid bilayer interactions studied with lipid bilayer arrays

    NASA Astrophysics Data System (ADS)

    Lu, Bin; Smith, Tyler; Schmidt, Jacob J.

    2015-04-01

    The widespread environmental presence and commercial use of nanoparticles have raised significant health concerns as a result of many in vitro and in vivo assays indicating toxicity of a wide range of nanoparticle species. Many of these assays have identified the ability of nanoparticles to damage cell membranes. These interactions can be studied in detail using artificial lipid bilayers, which can provide insight into the nature of the particle-membrane interaction through variation of membrane and solution properties not possible with cell-based assays. However, the scope of these studies can be limited because of the low throughput characteristic of lipid bilayer platforms. We have recently described an easy to use, parallel lipid bilayer platform which we have used to electrically investigate the activity of 60 nm diameter amine and carboxyl modified polystyrene nanoparticles (NH2-NP and COOH-NP) with over 1000 lipid bilayers while varying lipid composition, bilayer charge, ionic strength, pH, voltage, serum, particle concentration, and particle charge. Our results confirm recent studies finding activity of NH2-NP but not COOH-NP. Detailed analysis shows that NH2-NP formed pores 0.3-2.3 nm in radius, dependent on bilayer and solution composition. These interactions appear to be electrostatic, as they are regulated by NH2-NP surface charge, solution ionic strength, and bilayer charge. The ability to rapidly measure a large number of nanoparticle and membrane parameters indicates strong potential of this bilayer array platform for additional nanoparticle bilayer studies.The widespread environmental presence and commercial use of nanoparticles have raised significant health concerns as a result of many in vitro and in vivo assays indicating toxicity of a wide range of nanoparticle species. Many of these assays have identified the ability of nanoparticles to damage cell membranes. These interactions can be studied in detail using artificial lipid bilayers, which can provide insight into the nature of the particle-membrane interaction through variation of membrane and solution properties not possible with cell-based assays. However, the scope of these studies can be limited because of the low throughput characteristic of lipid bilayer platforms. We have recently described an easy to use, parallel lipid bilayer platform which we have used to electrically investigate the activity of 60 nm diameter amine and carboxyl modified polystyrene nanoparticles (NH2-NP and COOH-NP) with over 1000 lipid bilayers while varying lipid composition, bilayer charge, ionic strength, pH, voltage, serum, particle concentration, and particle charge. Our results confirm recent studies finding activity of NH2-NP but not COOH-NP. Detailed analysis shows that NH2-NP formed pores 0.3-2.3 nm in radius, dependent on bilayer and solution composition. These interactions appear to be electrostatic, as they are regulated by NH2-NP surface charge, solution ionic strength, and bilayer charge. The ability to rapidly measure a large number of nanoparticle and membrane parameters indicates strong potential of this bilayer array platform for additional nanoparticle bilayer studies. Electronic supplementary information (ESI) available: Impact of ionic strength on particle-membrane interaction in POPC : POPE : Chol : POPS (3 : 1 : 1 : 1) bilayers; impact of voltage magnitude, bilayer charge, voltage sign and ionic strength on pore size. See DOI: 10.1039/c4nr06892k

  10. Mimicking anhydrobiosis on solid supported lipid bilayers 

    E-print Network

    Chapa, Vanessa Alyss

    2007-09-17

    The studies presented in this thesis focus on the synthesis of air-stable solid supported lipid bilayers by anhydrobiotic mechanisms. Supported lipid bilayers (SLBs) serve as platforms that mimic cellular membrane surfaces in appearance and behavior...

  11. Lipid Trafficking in Plant Photosynthetic Cells

    Microsoft Academic Search

    Juliette Jouhet; Emmanuelle Dubots; Eric Maréchal; Maryse A. Block

    \\u000a Each of the various membranes in plant cells has a specific glycerolipid composition, which is kept relatively stable in different\\u000a cells and different plants. Lipid homeostasis effectors, particularly lipid transporters, remain largely uncharacterized.\\u000a Recent progresses in the field rely on the analysis of chloroplast lipid homeostasis as a model of choice. Galactolipids are\\u000a the main lipids of chloroplast membranes. Galactolipid

  12. Relationships between fatty acid composition of body lipids and lipid mobilization in rat.

    E-print Network

    Paris-Sud XI, Université de

    of liver lipid metabolism during dietary energy res- triction. 1 ntroduction. The fatty acid composition « exogenous» fatty acids affect the fatty acid composi- tion of total liver lipids. Introducing trioleateRelationships between fatty acid composition of body lipids and lipid mobilization in rat. II

  13. Lipid raft microdomains and neurotransmitter signalling

    Microsoft Academic Search

    John A. Allen; Robyn A. Halverson-Tamboli; Mark M. Rasenick

    2006-01-01

    Lipid rafts are specialized structures on the plasma membrane that have an altered lipid composition as well as links to the cytoskeleton. It has been proposed that these structures are membrane domains in which neurotransmitter signalling might occur through a clustering of receptors and components of receptor-activated signalling cascades. The localization of these proteins in lipid rafts, which is affected

  14. Integral hair lipid in human hair follicle

    Microsoft Academic Search

    Won-Soo Lee

    2011-01-01

    Integral hair lipid (IHL) is bound to the keratinized cell surface to make an environmentally resistant lipid envelope. It is mainly positioned on the hair cuticle and inner root sheath. IHL in the hair follicle may regard as hair barrier to be similar to the epidermal lipid layer functioning as skin barrier. Major constituents of IHL are fatty acid, phytosphingosine,

  15. Phase Transitions and Heterogeneity in Lipid Bilayers

    Microsoft Academic Search

    R. E. Pagano; R. J. Cherry; D. Chapman

    1973-01-01

    The optical reflectivity of several well-characterized lipid bilayer systems has been correlated with calorimetric studies of the membrane components. There is a large increase in mean membrane thickness when a bilayer is cooled below the transition temperature of the membrane lipid. Similar studies on membranes generated from a mixture of two lipids possessing different degrees of unsaturation suggest that between

  16. Original article Lipid utilization and carbohydrate partitioning

    E-print Network

    Paris-Sud XI, Université de

    Original article Lipid utilization and carbohydrate partitioning during germination of English — Conversion of reserve lipids in the seed, and carbohydrate and dry matter partitioning dur- ing in lipid content with a concomitant rise in carbohydrates (fig 2); starch appeared to be a transient sink

  17. Wave Propagation in Lipid Monolayers

    PubMed Central

    Griesbauer, J.; Wixforth, A.; Schneider, M.F.

    2009-01-01

    Abstract Sound waves are excited on lipid monolayers using a set of planar electrodes aligned in parallel with the excitable medium. By measuring the frequency-dependent change in the lateral pressure, we are able to extract the sound velocity for the entire monolayer phase diagram. We demonstrate that this velocity can also be directly derived from the lipid monolayer compressibility, and consequently displays a minimum in the phase transition regime. This minimum decreases from v0 = 170 m/s for one-component lipid monolayers down to vm = 50 m/s for lipid mixtures. No significant attenuation can be detected confirming an adiabatic phenomenon. Finally, our data propose a relative lateral density oscillation of ??/? ?2%, implying a change in all area-dependent physical properties. Order-of-magnitude estimates from static couplings therefore predict propagating changes in surface potential of 1–50 mV, 1 unit in pH (electrochemical potential), and 0.01 K in temperature, and fall within the same order of magnitude as physical changes measured during nerve pulse propagation. These results therefore strongly support the idea of propagating adiabatic sound waves along nerves as first thoroughly described by Kaufmann in 1989 and recently by Heimburg and Jackson, but already claimed by Wilke in 1912. PMID:19917224

  18. Resveratrol in Solid Lipid Nanoparticles

    Microsoft Academic Search

    Maria Eugenia Carlotti; Simona Sapino; Elena Ugazio; Marina Gallarate; Silvia Morel

    2011-01-01

    This report investigates the possibility of producing solid lipid nanoparticles as protective vehicle of resveratrol, an antioxidant characterised by a fast trans-cis isomerisation. SLN aqueous dispersions were produced by hot melt homogenisation technique and characterised. It was found that the presence of tetradecyl-?-cyclodextrin in SLN formulation induced an improvement of nanoparticle characteristics. Moreover a significant reduction in resveratrol photodegradation was

  19. Spontaneous Formation of Lipid Nanotubes and Lipid Nanofibers from Giant Charged Dendrimer Lipids

    NASA Astrophysics Data System (ADS)

    Zidovska, Alexandra; Ewert, Kai K.; Safinya, Cyrus R.; Quispe, Joel; Carragher, Bridgett; Potter, Clinton S.

    2007-03-01

    Liposomes have attracted much scientific interest due to their applications in model cells studies and in drug encapsulation. We report on the discovery of new vesicle phases formed in mixtures of MVLBG2, DOPC and water. MVLBG2 is a newly synthesized highly charged (16+) lipid (K. Ewert et al., JACS, 2006) with giant dendrimer headgroup thus leading to a high spontaneous curvature of the molecule. In combination with zero-curvature DOPC, MVLBG2 exhibits a rich phase diagram showing novel vesicle morphologies such as bones, lipid nanotubes and nanofibers as revealed by differential contrast microscopy (DIC) and cryo-TEM. At the micron scale DIC reveals a new phase consisting of bone-like vesicles. This novel morphology persists down to the nanometer scale as shown by cryo-TEM. The nanotubes are of diameter 10-50 nm, length > 1?m and consist of a single lipid bilayer. A surprising new morphology arises resulting from a spontaneous topological transition from tubes to lipid nanorods. Funded by DOE DE-FG-02-06ER46314, NIH GM-59288, NSF DMR-0503347.

  20. Periodic structures in lipid monolayer phase transitions

    PubMed Central

    McConnell, Harden M.; Tamm, Lukas K.; Weis, Robert M.

    1984-01-01

    Periodic patterns are observed when supported lipid monolayers doped with low concentrations of fluorescent lipid probes are observed with epi-fluorescence microscopy. Monolayers of dipalmitoyl phosphatidylcholine were examined on air-water interfaces and also on alkylated glass coverslips. The patterns are formed by periodic arrays of solid-phase lipid domains in equilibrium with fluid-phase lipid under specified conditions of temperature and two-dimensional lipid pressure. Electrostatic forces may stabilize the periodic ordering of the solid domains. Images PMID:16593467

  1. Lipid domains in HIV-1 assembly

    PubMed Central

    Yandrapalli, Naresh; Muriaux, Delphine; Favard, Cyril

    2014-01-01

    In CD+4 T cells, HIV-1 buds from the host cell plasma membrane. The viral Gag polyprotein is mainly responsible for this process. However, the intimate interaction of Gag and lipids at the plasma membrane as well as its consequences, in terms of lipids lateral organization and virus assembly, is still under debate. In this review we propose to revisit the role of plasma membrane lipids in HIV-1 Gag targeting and assembly, at the light of lipid membranes biophysics and literature dealing with Gag-lipid interactions. PMID:24904536

  2. 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.

  3. 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

  4. Milk lipid secretion: recent biomolecular aspects

    PubMed Central

    McManaman, James L.

    2014-01-01

    Neonates of most species depend on milk lipids for calories, fat-soluble vitamins, and bioactive lipid components for growth and development during the postnatal period. To meet neonatal nutrition and development needs, the mammary gland has evolved efficient mechanisms for synthesizing and secreting large quantities of lipid during lactation. Although the biochemical steps involved in milk lipid synthesis are understood, the identities of the genes mediating these steps and the molecular physiology of milk lipid production and secretion have only recently begun to be understood in detail through advances in mouse genetics, gene expression analysis, protein structural properties, and the cell biology of lipid metabolism. This review discusses emerging data about the molecular, cellular, and structural determinants of milk lipid synthesis and secretion within the context of physiological functions. PMID:24605173

  5. Correlation between lipid plane curvature and lipid chain order.

    PubMed Central

    Lafleur, M; Bloom, M; Eikenberry, E F; Gruner, S M; Han, Y; Cullis, P R

    1996-01-01

    The 1-palmitoyl-2-oleoyl-phosphatidylethanolamine: 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPE:POPC) system has been investigated by measuring, in the inverted hexagonal (HII) phase, the intercylinder spacings (using x-ray diffraction) and orientational order of the acyl chains (using 2H nuclear magnetic resonance). The presence of 20 wt% dodecane leads to the formation of a HII phase for the composition range from 0 to 39 mol% of POPC in POPE, as ascertained by x-ray diffraction and 2H nuclear magnetic resonance. The addition of the alkane induces a small decrease in chain order, consistent with less stretched chains. An increase in temperature or in POPE proportion leads to a reduction in the intercylinder spacing, primarily due to a decrease in the water core radius. A temperature increase also leads to a reduction in the orientational order of the lipid acyl chains, whereas the POPE proportion has little effect on chain order. A correlation is proposed to relate the radius of curvature of the cylinders in the inverted hexagonal phase to the chain order of the lipids adopting the HII phase. A simple geometrical model is proposed, taking into account the area occupied by the polar headgroup at the interface and the orientational order of the acyl chains reflecting the contribution of the apolar core. From these parameters, intercylinder spacings are calculated that agree well with the values determined experimentally by x-ray diffraction, for the variations of both temperature and POPE:POPC proportion. This model suggests that temperature increases the curvature of lipid layers, mainly by increasing the area subtended by the hydrophobic core through chain conformation disorder, whereas POPC content affects primarily the headgroup interface contribution. The frustration of lipid layer curvature is also shown to be reflected in the acyl chain order measured in the L alpha phase, in the absence of dodecane; for a given temperature, increased order is observed when the curling tendencies of the lipid plane are more pronounced. PMID:8744312

  6. Targeting Protein Lipidation in Disease

    PubMed Central

    Resh, Marilyn D.

    2012-01-01

    Fatty acids and/or isoprenoids are covalently attached to a variety of disease-related proteins. The distinct chemical properties of each of these hydrophobic moieties allow lipid modification to serve as a mechanism to regulate protein structure, localization and function. This review highlights recent progress in identifying inhibitors of protein lipidation and their effects on human disease. Myristoylation inhibitors have shown promise in blocking the action of human pathogens. Although inhibitors that block prenylation of Ras proteins have not yet been successful for cancer treatment, they may be efficacious in the rare premature aging syndrome progeria. Agents that alter the palmitoylation status of Ras, Wnt and Hh proteins have recently been discovered, and represent the next generation of potential chemotherapeutics. PMID:22342806

  7. 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

  8. Niacin, lipids, and heart disease

    Microsoft Academic Search

    Shaista Malik; Moti L. Kashyap

    2003-01-01

    Niacin is the most effective medication in current clinical use for increasing high-density lipoprotein (HDL) cholesterol.\\u000a It has the broadest effect on the lipid profile, reducing all atherogenic apolipoprotein (apo) B and increasing all antiatherogenic\\u000a apo AI-containing lipoproteins, resulting in significant reduction in atherosclerotic complications and total mortality in\\u000a trials. Recent research indicates novel major target sites of action in

  9. Proton permeation of lipid bilayers.

    PubMed

    Deamer, D W

    1987-10-01

    Proton permeation of the lipid bilayer barrier has two unique features. First, permeability coefficients measured at neutral pH ranges are six to seven orders of magnitude greater than expected from knowledge of other monovalent cations. Second, proton conductance across planar lipid bilayers varies at most by a factor of 10 when pH is varied from near 1 to near 11. Two mechanisms have been proposed to account for this anomalous behavior: proton conductance related to contaminants of lipid bilayers, and proton translocation along transient hydrogen-bonded chains (tHBC) of associated water molecules in the membrane. The weight of evidence suggests that trace contaminants may contribute to proton conductance across planar lipid membranes at certain pH ranges, but cannot account for the anomalous proton flux in liposome systems. Two new results will be reported here which were designed to test the tHBC model. These include measurements of relative proton/potassium permeability in the gramicidin channel, and plots of proton flux against the magnitude of pH gradients. (1) The relative permeabilities of protons and potassium through the gramicidin channel, which contains a single strand of hydrogen-bonded water molecules, were found to differ by at least four orders of magnitude when measured at neutral pH ranges. This result demonstrates that a hydrogen-bonded chain of water molecules can provide substantial discrimination between protons and other cations. It was also possible to calculate that if approximately 7% of bilayer water was present in a transient configuration similar to that of the gramicidin channel, it could account for the measured proton flux. (2) The plot of proton conductance against pH gradient across liposome membranes was superlinear, a result that is consistent with one of three alternative tHBC models for proton conductance described by Nagle elsewhere in this volume. PMID:2447068

  10. [News in lipid lowering treatment].

    PubMed

    Vrablík, Michal; ?eška, Richard

    2014-11-01

    Options for modification of lipoprotein metabolism and, thus, for reduction of atherothrombotic complication have widened over recent years. Apart from the development of novel approaches new pharmacological formulations of common lipid lowering drugs have been prepared- e.g. statin-containing nanoparticles, fibrate nanoparticles with a much higher bioavailability etc. Even the oldest lipid lowering agents - resins - have not been forgotten due to its once again discovered positive impact of these agents on glucose homeostasis while optimally complementing the action of statins. Clinical trials of therapies targeting HDL particle metabolism are being in progress despite we have not gathered any unambiguous evidence of positive effect of the CETP inhibitors or apoA1 mime-tics on the progression of atherosclerosis. Brand new approaches in the treatment of dyslipidemia including MTTP and PCSK9 inhibition or therapies utilizing anti-sense technologies rapidly accumulate evidence from clinical studies. We have already learned about their lipid-modifying efficacy particularly in patients with familial hypercholesterolemia, however, data from other patients´ populations can be expected quite soon. PMID:25600041

  11. Lipid transport by mammalian ABC proteins.

    PubMed

    Quazi, Faraz; Molday, Robert S

    2011-09-01

    ABC (ATP-binding cassette) proteins actively transport a wide variety of substrates, including peptides, amino acids, sugars, metals, drugs, vitamins and lipids, across extracellular and intracellular membranes. Of the 49 hum an ABC proteins, a significant number are known to mediate the extrusion of lipids from membranes or the flipping of membrane lipids across the bilayer to generate and maintain membrane lipid asymmetry. Typical lipid substrates include phospholipids, sterols, sphingolipids, bile acids and related lipid conjugates. Members of the ABCA subfamily of ABC transporters and other ABC proteins such as ABCB4, ABCG1 and ABCG5/8 implicated in lipid transport play important roles in diverse biological processes such as cell signalling, membrane lipid asymmetry, removal of potentially toxic compounds and metabolites, and apoptosis. The importance of these ABC lipid transporters in cell physiology is evident from the finding that mutations in the genes encoding many of these proteins are responsible for severe inherited diseases. For example, mutations in ABCA1 cause Tangier disease associated with defective efflux of cholesterol and phosphatidylcholine from the plasma membrane to the lipid acceptor protein apoA1 (apolipoprotein AI), mutations in ABCA3 cause neonatal surfactant deficiency associated with a loss in secretion of the lipid pulmonary surfactants from lungs of newborns, mutations in ABCA4 cause Stargardt macular degeneration, a retinal degenerative disease linked to the reduced clearance of retinoid compounds from photoreceptor cells, mutations in ABCA12 cause harlequin and lamellar ichthyosis, skin diseases associated with defective lipid trafficking in keratinocytes, and mutations in ABCB4 and ABCG5/ABCG8 are responsible for progressive intrafamilial hepatic disease and sitosterolaemia associated with defective phospholipid and sterol transport respectively. This chapter highlights the involvement of various mammalian ABC transporters in lipid transport in the context of their role in cell signalling, cellular homoeostasis, apoptosis and inherited disorders. PMID:21967062

  12. Formation of milk lipids: a molecular perspective

    PubMed Central

    McManaman, James L

    2015-01-01

    Lipids, primarily triglycerides, are major milk constituents of most mammals, providing a large percentage of calories, essential fatty acids and bioactive lipids required for neonatal growth and development. To meet the caloric and nutritional demands of newborns, the mammary glands of most species have evolved an enormous capacity to synthesize and secrete large quantities of lipids during lactation. Significant information exists regarding the physiological regulation of lipid metabolism in the mammary gland from the study of dairy animals. However, detailed understanding of the molecular mechanisms regulating milk lipid formation is only now coming into focus through advances in mouse genetics, global analysis of mammary gland gene expression, organelle protein properties and the cell biology of lipid metabolism. PMID:21366863

  13. Domain Coupling in Asymmetric Lipid Bilayers

    PubMed Central

    Kiessling, Volker; Wan, Chen; Tamm, Lukas K.

    2011-01-01

    Biological membranes are heterogeneous assemblies of lipids, proteins, and cholesterol that are organized as asymmetric bimolecular leaflets of lipids with embedded proteins. Modulated by the concentration of cholesterol lipids and proteins may segregate into two or more liquid phases with different physical properties that can coexist in the same membrane. In this review, we summarize recent advances on how this situation can be recreated in a supported bilayer format and how this system has been used to demonstrate the induction of ordered lipid domains in lipid compositions that are typical for the inner leaflet by lipid compositions that are typical for the outer leaflet of mammalian plasma membranes. Proteins are shown to differentially target such induced inner leaflet domains. PMID:18848518

  14. Lipid sac area as a proxy for individual lipid content of arctic calanoid copepods

    PubMed Central

    Vogedes, Daniel; Varpe, Řystein; Sřreide, Janne E.; Graeve, Martin; Berge, Jřrgen; Falk-Petersen, Stig

    2010-01-01

    We present an accurate, fast, simple and non-destructive photographic method to estimate wax ester and lipid content in single individuals of the calanoid copepod genus Calanus and test this method against gas-chromatographic lipid measurements. PMID:20824043

  15. Identification and composition of turnip root lipids

    Microsoft Academic Search

    Marius Lepage

    1967-01-01

    Two varieties of turnip, Laurentian and Wye, were examined for their lipid and fatty acid composition. Lipids extracted with\\u000a 80% ethanol contained variable quantities of phosphatidic acid, which was considered to be an artifact. Crude lipids were\\u000a fractionated by TLC, and fatty acids and sterols were analyzed by GLC. Among the common phospholipids, cardiolipid and phosphatidyl\\u000a glycerol were abundant components.

  16. Lipid composition of oats ( Avena sativa L.)

    Microsoft Academic Search

    M. R. Sahasrabudhe

    1979-01-01

    Compositions of lipids extracted from a sample of Hinoat oat by seven solvent systems and that extracted with chloroform\\/methanol\\u000a (2:1 v\\/v) from six selected cultivars representing high and low lipid contents are reported. Lipid components (steryl esters,\\u000a triglycerides, partial glycerides, free fatty acids, glycolipids and phospholipids) were separated by silicic acid column\\u000a chromatography and thin layer chromatography and quantitated by

  17. Plasma lipid concentrations during episodic occupational stress

    Microsoft Academic Search

    Barbara S. McCann; G. Andrew H. Benjamin; Charles W. Wilkinson; Barbara M. Retzlaff; Joan Russo; Robert H. Knopp

    1999-01-01

    The possibility that stress affects plasma lipid concentrations has been the subject of recent investigation, but the findings\\u000a are equivocal in nonlaboratory settings. To determine whether psychological stress contributes to variability in plasma lipid\\u000a concentrations and concomitant changes in health behaviors, the effect of increased work load on plasma lipids and apolipoproteins\\u000a was examined in 173 lawyers. Plasma cholesterol, triglyceride,

  18. Sleep-Inducing Effect of L-Tryptophane

    Microsoft Academic Search

    E. Körner; G. Bertha; E. Flooh; B. Reinhart; R. Wolf; H. Lechner

    1986-01-01

    Night sleep recordings were performed in 10 patients with sleep disturbances in falling asleep as well as in maintaining sleep using a mobile 4-channel EEG registration system. Three consecutive nights, which were spent under different conditions, were evaluated automatically. The first night without treatment was used as a baseline night to objectify the disturbed sleep, the second night was measured

  19. Near infrared Raman spectra of human brain lipids

    Microsoft Academic Search

    Christoph Krafft; Lars Neudert; Thomas Simat; Reiner Salzer

    2005-01-01

    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

  20. Lipids of the products of processing of cotton seeds

    Microsoft Academic Search

    M. Talipova; T. V. Chernenko; A. I. Glushenkova

    1989-01-01

    The free, bound, and strongly bound lipids of the crushed seeds, pulp, husks, and meal have been characterized. It has been shown that the bound and strongly-bound lipids differ from the free lipids by a higher level of saturated acids. The acid numbers of the bound lipids are 5–6 times higher than those of the free lipids.

  1. Lipid regulation of BK channel function

    PubMed Central

    Dopico, Alex M.; Bukiya, Anna N.

    2014-01-01

    This mini-review focuses on lipid modulation of BK (MaxiK, BKCa) current by a direct interaction between lipid and the BK subunits and/or their immediate lipid environment. Direct lipid-BK protein interactions have been proposed for fatty and epoxyeicosatrienoic acids, phosphoinositides and cholesterol, evidence for such action being less clear for other lipids. BK ? (slo1) subunits are sufficient to support current perturbation by fatty and epoxyeicosatrienoic acids, glycerophospholipids and cholesterol, while distinct BK ? subunits seem necessary for current modulation by most steroids. Subunit domains or amino acids that participate in lipid action have been identified in a few cases: hslo1 Y318, cerebral artery smooth muscle (cbv1) R334,K335,K336, cbv1 seven cytosolic CRAC domains, slo1 STREX and ?1 T169,L172,L173 for docosahexaenoic acid, PIP2, cholesterol, sulfatides, and cholane steroids, respectively. Whether these protein motifs directly bind lipids or rather transmit the energy of lipid binding to other areas and trigger protein conformation change remains unresolved. The impact of direct lipid-BK interaction on physiology is briefly discussed. PMID:25202277

  2. Polar lipid composition of mammalian hair.

    PubMed

    Wix, M A; Wertz, P W; Downing, D T

    1987-01-01

    The types and amounts of polar lipids from the hair of monkey (Macacca fascicularis), dog (Canis familiaris), pig (Sus scrofa) and porcupine (Erethizon dorsatum) have been determined by quantitative thin-layer chromatography. The polar lipid content of the hair samples ranged from 0.6 to 1.6 wt%. Lipid compositions included ceramides (57-63% of the polar lipid by weight), glycosphingolipids (7-9%) and cholesteryl sulfate (22-29%). Several minor components (4-7%) remain unidentified. The results suggest that cholesteryl sulfate may be an important determinant of the cohesiveness of hair. PMID:3581794

  3. Lipid Cell Signaling Genomics, Proteomics, and Metabolomics

    E-print Network

    Gleeson, Joseph G.

    Metabolism and Cell Signaling 2 Fatty Acid Metabolism, Signaling, and Lipidomics 3 Essential Fatty Acids, Fish Oils, Eicosanoid Signaling, Inflammation, and Lipidomics 4 Interrogating Gene, Protein and Lipid

  4. 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

  5. Lipid Nanoparticles for Ocular Gene Delivery.

    PubMed

    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

  6. START ships lipids across interorganelle space.

    PubMed

    Alpy, Fabien; Tomasetto, Catherine

    2014-01-01

    The family of StAR related lipid transfer proteins (START) is so-named based on the distinctive capacity for these proteins to transport lipids between membranes. The START domain is a module of about 210 residues, which binds lipids such as glycerolipids, sphingolipids and sterols. This domain has a deep lipid-binding pocket - which shields the hydrophic ligand from the external aqueous environment - covered by a lid. Based on their homology, the fifteen START proteins in mammals have been allocated to six distinct subfamilies, each subfamily being more specialized in the transport and/or sensing of a lipid ligand species. However within the same subgroup, their expression profile and their subcellular localization distinguish them and are critical for their different biological functions. Indeed, START proteins act in a variety of distinct physiological processes, such as lipid transfer between intracellular compartments, lipid metabolism and modulation of signaling events. Mutation or deregulated expression of START proteins is linked to pathological processes, including genetic disorders, autoimmune diseases and cancers. Besides the common single START domain, which is always located at the carboxy-terminal end in mammals, most START proteins harbor additional domains predicted to be critical in favoring lipid exchange. Evidence from well characterized START proteins indicates that these additional domains might be tethering machineries able to bring distinct organelles together and create membrane contact sites prone to lipid exchange via the START domain. PMID:24076129

  7. 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

  8. Rapid Microfluidic Perfusion Enabling Kinetic Studies of Lipid Ion Channels in a Bilayer Lipid Membrane Chip

    PubMed Central

    Shao, Chenren; Sun, Bing; Colombini, Marco; DeVoe, Don L.

    2012-01-01

    There is growing recognition that lipids play key roles in ion channel physiology, both through the dynamic formation and dissolution of lipid ion channels and by indirect regulation of protein ion channels. Because existing technologies cannot rapidly modulate the local (bio)chemical conditions at artificial bilayer lipid membranes used in ion channel studies, the ability to elucidate the dynamics of these lipid–lipid and lipid–protein interactions has been limited. Here we demonstrate a microfluidic system supporting exceptionally rapid perfusion of reagents to an on-chip bilayer lipid membrane, enabling the responses of lipid ion channels to dynamic changes in membrane boundary conditions to be probed. The thermoplastic microfluidic system allows initial perfusion of reagents to the membrane in less than 1 s, and enables kinetic behaviors with time constants below 10 s to be directly measured. Application of the platform is demonstrated toward kinetic studies of ceramide, a biologically important lipid known to self-assemble into transmembrane ion channels, in response to dynamic treatments of small ions (La3+) and proteins (Bcl-xL mutant). The results reveal the broader potential of the technology for studies of membrane biophysics, including lipid ion channel dynamics, lipid–protein interactions, and the regulation of protein ion channels by lipid micro domains. PMID:21556947

  9. 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 ...

  10. 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.

  11. Plasma lipids and lipoproteins and essential hypertension

    Microsoft Academic Search

    M. Flesch; A. Sachinidis; Y. D. Ko; K. Kraft; H. Vetter

    1994-01-01

    In recent years there have been many studies demonstrating a correlation between increased arterial blood pressure and altered lipid profiles, and there has been an especially positive correlation between high cholesterol levels and blood pressure. There are differences between the various reports that are important. In our study the lipid distribution in 105 hypertensive patients with mild or moderate arterial

  12. 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.

  13. Lipid Peroxidation Induced by Expandable Clay Minerals

    E-print Network

    Ahmad, Sajjad

    Lipid Peroxidation Induced by Expandable Clay Minerals D A R I A K I B A N O V A , A N T O N I O N and toxicity. Herein, potential hazards of clay particle uptake areaddressed.Thispaperreportsthatthecontentanddistribution of structural Fe influence the ability of expandable clay minerals to induce lipid peroxidation (LP), a major

  14. Forum Editorial Lipid Rafts and Redox Signaling

    Microsoft Academic Search

    PIN-LAN LI; ERICH GULBINS

    2007-01-01

    In addition to the amplifying action of enzymes in the cell-signaling cascade, another important mechanism has been shown to amplify the signals massively when ligands bind to their receptors, which is characterized by clustering of membrane lipid microdomains or lipid rafts and formation of various signaling platforms. In this process, many receptor molecules aggregate on stimulation, thereby resulting in a

  15. Water Permeability of Thin Lipid Membranes

    Microsoft Academic Search

    ALBERT CASS; ALAN FINKELSTEIN

    1967-01-01

    The osmotic permeability coefficient, Pf, and the tagged water permeability coefficient, Pn, were determined for thin (< 100 A) lipid mem- branes formed from ox brain lipids plus DL-a-tocopherol; their value of approxi- mately 1 X 10 -3 era\\/see is within the range reported for plasma membranes. It was established that Pf = Pa. Other reports that Pf > Pn

  16. Keratins and lipids in ethnic hair.

    PubMed

    Cruz, C F; Fernandes, M M; Gomes, A C; Coderch, L; Martí, M; Méndez, S; Gales, L; Azoia, N G; Shimanovich, U; Cavaco-Paulo, A

    2013-06-01

    Human hair has an important and undeniable relevance in society due to its important role in visual appearance and social communication. Hair is mainly composed of structural proteins, mainly keratin and keratin associated proteins and lipids. Herein, we report a comprehensive study of the content and distribution of the lipids among ethnic hair, African, Asian and Caucasian hair. More interestingly, we also report the study of the interaction between those two main components of hair, specifically, the influence of the hair internal lipids in the structure of the hair keratin. This was achieved by the use of a complete set of analytical tools, such as thin layer chromatography-flame ionization detector, X-ray analysis, molecular dynamics simulation and confocal microscopy. The experimental results indicated different amounts of lipids on ethnic hair compositions and higher percentage of hair internal lipids in African hair. In this type of hair, the axial diffraction of keratin was not observed in X-ray analysis, but after hair lipids removal, the keratin returned to its typical packing arrangement. In molecular dynamic simulation, lipids were shown to intercalate dimers of keratin, changing its structure. From those results, we assume that keratin structure may be influenced by higher concentration of lipids in African hair. PMID:23301816

  17. Intravenous lipid emulsion in clinical toxicology

    PubMed Central

    2010-01-01

    Intravenous lipid emulsion is an established, effective treatment for local anesthetic-induced cardiovascular collapse. The predominant theory for its mechanism of action is that by creating an expanded, intravascular lipid phase, equilibria are established that drive the offending drug from target tissues into the newly formed 'lipid sink'. Based on this hypothesis, lipid emulsion has been considered a candidate for generic reversal of toxicity caused by overdose of any lipophilic drug. Recent case reports of successful resuscitation suggest the efficacy of lipid emulsion infusion for treating non-local anesthetic overdoses across a wide spectrum of drugs: beta blockers, calcium channel blockers, parasiticides, herbicides and several varieties of psychotropic agents. Lipid emulsion therapy is gaining acceptance in emergency rooms and other critical care settings as a possible treatment for lipophilic drug toxicity. While protocols exist for administration of lipid emulsion in the setting of local anesthetic toxicity, no optimal regimen has been established for treatment of acute non-local anesthetic poisonings. Future studies will shape the evolving recommendations for lipid emulsion in the setting of non-local anesthetic drug overdose. PMID:20923546

  18. Lipid rafts: contentious only from simplistic standpoints

    Microsoft Academic Search

    John F. Hancock

    2006-01-01

    The hypothesis that lipid rafts exist in plasma membranes and have crucial biological functions remains controversial. The lateral heterogeneity of proteins in the plasma membrane is undisputed, but the contribution of cholesterol-dependent lipid assemblies to this complex, non-random organization promotes vigorous debate. In the light of recent studies with model membranes, computational modelling and innovative cell biology, I propose an

  19. Extraction and Analysis of Food Lipids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Along with proteins and carbohydrates, lipids are one of the main components of foods. Lipids are often defined as a group of biomolecules that are insoluble in water and soluble in organic solvents such as hexane, diethyl ether or chloroform. Modern methods for the extraction and analysis of lipi...

  20. 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 ...

  1. Angptl3 regulates lipid metabolism in mice

    Microsoft Academic Search

    Yosuke Ando; Mitsuru Ono; Mitsuru Shimamura; Hiroaki Yasumo; Toshihiko Fujiwara; Hiroyoshi Horikoshi; Hidehiko Furukawa; Ryuta Koishi

    2002-01-01

    The KK obese mouse is moderately obese and has abnormally high levels of plasma insulin (hyperinsulinemia), glucose (hyperglycemia) and lipids (hyperlipidemia). In one strain (KK\\/San), we observed abnormally low plasma lipid levels (hypolipidemia). This mutant phenotype is inherited recessively as a mendelian trait. Here we report the mapping of the hypolipidemia (hypl) locus to the middle of chromosome 4 and

  2. Effect of extrusion pressure and lipid properties on the size and polydispersity of lipid vesicles.

    PubMed Central

    Hunter, D G; Frisken, B J

    1998-01-01

    The production of vesicles, spherical shells formed from lipid bilayers, is an important aspect of their recent application to drug delivery technologies. One popular production method involves pushing a lipid suspension through cylindrical pores in polycarbonate membranes. However, the actual mechanism by which the polydisperse, multilamellar lipid suspension breaks up into a relatively monodisperse population of vesicles is not well understood. To learn about factors influencing this process, we have characterized vesicles produced under different extrusion parameters and from different lipids. We find that extruded vesicles are only produced above a certain threshold extrusion pressure and have sizes that depend on the extrusion pressure. The minimum pressure appears to be associated with the lysis tension of the lipid bilayer rather than any bending modulus of the system. The flow rate of equal concentration lipid solutions through the pores, after being corrected for the viscosity of water, is independent of lipid properties. PMID:9635753

  3. Shotgun lipidomics of neutral lipids as an enabling technology for elucidation of lipid-related diseases

    PubMed Central

    Gross, Richard W.; Han, Xianlin

    2009-01-01

    Neutral lipids fulfill multiple specialized roles in cellular function. These roles include energy storage and utilization, the synthesis of complex lipids in cellular membranes, lipid second messengers for cellular signaling, and the modulation of membrane molecular dynamics. We have developed a novel mass spectrometric technology, now termed shotgun lipidomics, that can identify the types and amounts of thousands of lipids directly from extracts of biological samples. Shotgun lipidomics is well suited for the identification and measurement of the types and amounts of neutral lipid classes and individual molecular species through the use of multidimensional mass spectrometry. This review summarizes the basic principles underlying the use of shotgun lipidomics for the direct measurement of neutral lipids from extracts of biological tissues or fluids. Through exploiting the high information content inherent in shotgun lipidomics, this technology promises to greatly facilitate advances in our understanding of alterations in neutral lipid metabolism in health and disease. PMID:19126783

  4. Diffusion in low-dimensional lipid membranes.

    PubMed

    Heath, George R; Roth, Johannes; Connell, Simon D; Evans, Stephen D

    2014-10-01

    The diffusion behavior of biological components in cellular membranes is vital to the function of cells. By collapsing the complexity of planar 2D membranes down to one dimension, fundamental investigations of bimolecular behavior become possible in one dimension. Here we develop lipid nanolithography methods to produce membranes, under fluid, with widths as low as 6 nm but extending to microns in length. We find reduced lipid mobility, as the width is reduced below 50 nm, suggesting different lipid packing in the vicinity of boundaries. The insertion of a membrane protein, M2, into these systems, allowed characterization of protein diffusion using high-speed AFM to demonstrate the first membrane protein 1D random walk. These quasi-1D lipid bilayers are ideal for testing and understanding fundamental concepts about the roles of dimensionality and size on physical properties of membranes from energy transfer to lipid packing. PMID:25166509

  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. Lipid homeostasis in macrophages - implications for atherosclerosis.

    PubMed

    Schmitz, G; Grandl, M

    2008-01-01

    In industrialized societies with excess food supply, obesity is an expanding problem. As a result of metabolic overload, besides obesity, insulin resistance, type-2 diabetes, dyslipidemia, hypertension, and atherosclerosis develop, which together make up the metabolic syndrome. The imbalance of lipid uptake, metabolism, and removal in many organs such as the liver, muscle, adipose tissue, vessel wall, and macrophages triggers organ transdifferentiation toward lipid storage phenotypes. Macrophages, foam cells, and osteoclasts in calcifying lesions are a hallmark of atherosclerosis and the metabolic syndrome, and must be regarded as an important therapeutic target. In this review, pathways regulating lipid homeostasis in macrophages are updated. These include lipid influx through different receptor entry pathways, the role of membrane microdomains, endolysosomal and cytosolic lipid storage leading to phospholipidosis, and lipid droplet accumulation or activation of lipid efflux either through the Golgi system or bypassing this organelle on the way to the plasma membrane. The interdependence of these pathways and pharmacological modifications are described. The monocyte innate immunity receptor complex in defining monocyte subpopulations and their role in cardiovascular disease is taken into account. The composition of certain molecular lipid species in membrane microdomains and other organelles is essential for cellular functions affecting raft dynamics, signal transduction, and membrane and organelle trafficking. It is very likely that the underlying defects in lipid-associated rare genetic diseases such as ABCA1 deficiency, Niemann-Pick disease type C, as well as the more frequent complex disorders associated with atherosclerosis and phospholipidosis are related to disturbances in membrane homeostasis, signal transduction, and cellular lipid metabolism. PMID:18425439

  7. Curvature-induced lipid segregation

    NASA Astrophysics Data System (ADS)

    Zheng, Bin; Meng, Qing-Tian; B. Selinger Robin, L.; V. Selinger, Jonathan; Ye, Fang-Fu

    2015-06-01

    We investigate how an externally imposed curvature influences lipid segregation on two-phase-coexistent membranes. We show that the bending-modulus contrast of the two phases and the curvature act together to yield a reduced effective line tension. On largely curved membranes, a state of multiple domains (or rafts) forms due to a mechanism analogous to that causing magnetic-vortex formation in type-II superconductors. We determine the criterion for such a multi-domain state to occur; we then calculate respectively the size of the domains formed on cylindrically and spherically curved membranes. Project supported by the Hundred-Talent Program of the Chinese Academy of Sciences (FY) and the National Science Foundation of USA via Grant DMR-1106014 (RLBS, JVS).

  8. The influence of zwitterionic lipids on the electrostatic adsorption of macroions onto mixed lipid membranes

    NASA Astrophysics Data System (ADS)

    Haugen, Andrew; May, Sylvio

    2007-12-01

    Charged lipid membranes commonly consist of a mixture of charged and zwitterionic lipids. We suggest a model that characterizes the influence of the dipolar nature of the zwitterionic lipid species on the electrostatic adsorption of macroions onto mixed membranes in the fluid state. The model is based on Poisson-Boltzmann theory which we have modified so as to account for the dipolar character of the zwitterionic lipids. In addition the membrane lipids are allowed to adjust their lateral distribution upon macroion adsorption. We consider and compare two experimentally relevant scenarios: cationic macroions adsorbed onto anionic membranes and anionic macroions adsorbed onto cationic membranes. We show that in the former case the adsorption strength is slightly weakened by the presence of the headgroup dipoles of the zwitterionic lipids. Here, macroion-induced lipid demixing is more pronounced and the lipid headgroups tilt away from a cationic macroion upon adsorption. In contrast, for the adsorption of anionic macroions onto a cationic membrane the zwitterionic lipids strongly participate in the electrostatic interaction between membrane and macroion, thus enhancing the adsorption strength significantly (we predict up to 20%). Consistent with that we find less lateral demixing of the charged lipids and a reorientation of the dipoles of the zwitterionic headgroups towards the anionic macroions. Our results may be of importance to understand the differences in the electrostatic adsorption of proteins/peptides onto cellular membranes versus complex formation between cationic membranes and DNA.

  9. LipidHome: a database of theoretical lipids optimized for high throughput mass spectrometry lipidomics.

    PubMed

    Foster, Joseph M; Moreno, Pablo; Fabregat, Antonio; Hermjakob, Henning; Steinbeck, Christoph; Apweiler, Rolf; Wakelam, Michael J O; Vizcaíno, Juan Antonio

    2013-01-01

    Protein sequence databases are the pillar upon which modern proteomics is supported, representing a stable reference space of predicted and validated proteins. One example of such resources is UniProt, enriched with both expertly curated and automatic annotations. Taken largely for granted, similar mature resources such as UniProt are not available yet in some other "omics" fields, lipidomics being one of them. While having a seasoned community of wet lab scientists, lipidomics lies significantly behind proteomics in the adoption of data standards and other core bioinformatics concepts. This work aims to reduce the gap by developing an equivalent resource to UniProt called 'LipidHome', providing theoretically generated lipid molecules and useful metadata. Using the 'FASTLipid' Java library, a database was populated with theoretical lipids, generated from a set of community agreed upon chemical bounds. In parallel, a web application was developed to present the information and provide computational access via a web service. Designed specifically to accommodate high throughput mass spectrometry based approaches, lipids are organised into a hierarchy that reflects the variety in the structural resolution of lipid identifications. Additionally, cross-references to other lipid related resources and papers that cite specific lipids were used to annotate lipid records. The web application encompasses a browser for viewing lipid records and a 'tools' section where an MS1 search engine is currently implemented. LipidHome can be accessed at http://www.ebi.ac.uk/apweiler-srv/lipidhome. PMID:23667450

  10. Molecular sorting of lipids by bacteriorhodopsin in dilauroylphosphatidylcholine/distearoylphosphatidylcholine lipid bilayers.

    PubMed Central

    Dumas, F; Sperotto, M M; Lebrun, M C; Tocanne, J F; Mouritsen, O G

    1997-01-01

    A combined experimental and theoretical study is performed on binary dilauroylphosphatidylcholine/distearoylphosphatidylcholine (DLPC/DSPC) lipid bilayer membranes incorporating bacteriorhodopsin (BR). The system is designed to investigate the possibility that BR, via a hydrophobic matching principle related to the difference in lipid bilayer hydrophobic thickness and protein hydrophobic length, can perform molecular sorting of the lipids at the lipid-protein interface, leading to lipid specificity/selectivity that is controlled solely by physical factors. The study takes advantage of the strongly nonideal mixing behavior of the DLPC/DSPC mixture and the fact that the average lipid acyl-chain length is strongly dependent on temperature, particularly in the main phase transition region. The experiments are based on fluorescence energy transfer techniques using specifically designed lipid analogs that can probe the lipid-protein interface. The theoretical calculations exploit a microscopic molecular interaction model that embodies the hydrophobic matching as a key parameter. At low temperatures, in the gel-gel coexistence region, experimental and theoretical data consistently indicate that BR is associated with the short-chain lipid DLPC. At moderate temperatures, in the fluid-gel coexistence region, BR remains in the fluid phase, which is mainly composed of short-chain lipid DLPC, but is enriched at the interface between the fluid and gel domains. At high temperatures, in the fluid phase, BR stays in the mixed lipid phase, and the theoretical data suggest a preference of the protein for the long-chain DSPC molecules at the expense of the short-chain DLPC molecules. The combined results of the experiments and the calculations provide evidence that a molecular sorting principle is active because of hydrophobic matching and that BR exhibits physical lipid selectivity. The results are discussed in the general context of membrane organization and compartmentalization and in terms of nanometer-scale lipid-domain formation. Images FIGURE 1 PMID:9336190

  11. Lipid bilayers: thermodynamics, structure, fluctuations, and interactions

    PubMed Central

    Tristram-Nagle, Stephanie; Nagle, John F.

    2009-01-01

    This article, adapted from our acceptance speech of the Avanti Award in Lipids at the 47th Biophysical Society meeting in San Antonio, 2003, summarizes over 30 years of research in the area of lipid bilayers. Beginning with a theoretical model of the phase transition (J.F.N.), we have proceeded experimentally using dilatometry and density centrifugation to study volume, differential scanning calorimetry to study heat capacity, and X-ray scattering techniques to study structure of lipid bilayers as a function of temperature. Electron density profiles of the gel and ripple phases have been obtained as well as profiles from several fluid phase lipids, which lead to many structural results that compliment molecular dynamics simulations from other groups. Using the theory of liquid crystallography plus oriented lipid samples, we are the first group to obtain both material parameters (KC and B) associated with the fluctuations in fluid phase lipids. This allows us to use fully hydrated lipid samples, as in vivo, to obtain the structure. PMID:14706737

  12. Lipid membrane reorganization induced by chemical recognition.

    PubMed Central

    Last, J A; Waggoner, T A; Sasaki, D Y

    2001-01-01

    Nanoscale structural reorganization of a lipid bilayer membrane induced by a chemical recognition event has been imaged using in situ atomic force microscopy (AFM). Supported lipid bilayers, composed of distearylphosphatidylcholine (DSPC) and a synthetic lipid functionalized with a Cu(2+) receptor, phase-separate into nanoscale domains that are distinguishable by the 9 A height difference between the two molecules. Upon binding of Cu(2+) the electrostatic nature of the receptor changes, causing a dispersion of the receptor molecules and subsequent shrinking of the structural features defined by the receptors in the membrane. Complete reversibility of the process was demonstrated through the removal of metal ions with EDTA. PMID:11606286

  13. Lipidated Peptidomimetics with Improved Antimicrobial Activity

    PubMed Central

    2012-01-01

    We report a series of lipidated ?-AApeptides that mimic the structure and function of natural antimicrobial lipopeptides. Several short lipidated ?-AApeptides show broad-spectrum activity against a range of clinically related Gram-positive and Gram-negative bacteria as well as fungus. Their antimicrobial activity and selectivity are comparable or even superior to the clinical candidate pexiganan as well as previously reported linear ?-AApeptides. The further development of lipidated ?-AApeptides will lead to a new class of antibiotics to combat drug resistance. PMID:24900530

  14. Lipid arrays identify myelin-derived lipids and lipid complexes as prominent targets for oligoclonal band antibodies in multiple sclerosis

    PubMed Central

    Brennan, Kathryn M.; Galban-Horcajo, Francesc; Rinaldi, Simon; O'Leary, Colin P.; Goodyear, Carl S.; Kalna, Gabriela; Arthur, Ariel; Elliot, Christina; Barnett, Sue; Linington, Christopher; Bennett, Jeffrey L.; Owens, Gregory P.; Willison, Hugh J.

    2012-01-01

    The presence of oligoclonal bands of IgG (OCB) in cerebrospinal fluid (CSF) is used to establish a diagnosis of multiple sclerosis (MS), but their specificity has remained an enigma since its first description over forty years ago. We now report that the use of lipid arrays identifies heteromeric complexes of myelin derived lipids as a prominent target for this intrathecal B cell response. PMID:21872346

  15. Prediction of Body Lipid Change in Pregnancy and Lactation

    Microsoft Academic Search

    N. C. Friggens; K. L. Ingvartsen; G. C. Emmans

    2004-01-01

    A simple method to predict the genetically driven pattern of body lipid change through pregnancy and lactation in dairy cattle is proposed. The rationale and evidence for genetically driven body lipid change have their basis in evolutionary considerations and in the homeorhetic changes in lipid metabolism through the reproductive cycle. The inputs required to predict body lipid change are body

  16. Structural investigations on lipid nanoparticles containing high amounts of lecithin

    Microsoft Academic Search

    Martin Alexander Schubert; Meike Harms; Christel Charlotte Müller-Goymann

    2006-01-01

    Solid lipid nanoparticles (SLN), an alternative colloidal drug delivery system to polymer nanoparticles, emulsions and liposomes, possess inherent low incorporation rates resulting from the crystalline structure of the solid lipid. To increase the drug loading capacity of SLN, matrix modification by incorporation of the amphiphilic lipid lecithin within the lipid matrices has been proposed as a promising alternative. The objective

  17. Role of cholesterol and lipid organization in disease

    Microsoft Academic Search

    Frederick R. Maxfield; Ira Tabas

    2005-01-01

    Membrane lipids are essential for biological functions ranging from membrane trafficking to signal transduction. The composition of lipid membranes influences their organization and properties, so it is not surprising that disorders in lipid metabolism and transport have a role in human disease. Significant recent progress has enhanced our understanding of the molecular and cellular basis of lipid-associated disorders such as

  18. Lipid rafts: heterogeneity on the high seas.

    PubMed Central

    Pike, Linda J

    2004-01-01

    Lipid rafts are membrane microdomains that are enriched in cholesterol and glycosphingolipids. They have been implicated in processes as diverse as signal transduction, endocytosis and cholesterol trafficking. Recent evidence suggests that this diversity of function is accompanied by a diversity in the composition of lipid rafts. The rafts in cells appear to be heterogeneous both in terms of their protein and their lipid content, and can be localized to different regions of the cell. This review summarizes the data supporting the concept of heterogeneity among lipid rafts and outlines the evidence for cross-talk between raft components. Based on differences in the ways in which proteins interact with rafts, the Induced-Fit Model of Raft Heterogeneity is proposed to explain the establishment and maintenance of heterogeneity within raft populations. PMID:14662007

  19. Voltage-Gated Lipid Ion Channels

    PubMed Central

    Blicher, Andreas; Heimburg, Thomas

    2013-01-01

    Synthetic lipid membranes can display channel-like ion conduction events even in the absence of proteins. We show here that these events are voltage-gated with a quadratic voltage dependence as expected from electrostatic theory of capacitors. To this end, we recorded channel traces and current histograms in patch-experiments on lipid membranes. We derived a theoretical current-voltage relationship for pores in lipid membranes that describes the experimental data very well when assuming an asymmetric membrane. We determined the equilibrium constant between closed and open state and the open probability as a function of voltage. The voltage-dependence of the lipid pores is found comparable to that of protein channels. Lifetime distributions of open and closed events indicate that the channel open distribution does not follow exponential statistics but rather power law behavior for long open times. PMID:23823188

  20. 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 ...

  1. Composite S-layer lipid structures

    PubMed Central

    Schuster, Bernhard; Sleytr, Uwe B.

    2010-01-01

    Designing and utilization of biomimetic membrane systems generated by bottom-up processes is a rapidly growing scientific and engineering field. Elucidation of the supramolecular construction principle of archaeal cell envelopes composed of S-layer stabilized lipid membranes led to new strategies for generating highly stable functional lipid membranes at meso- and macroscopic scale. In this review, we provide a state of the art survey how S-layer proteins, lipids, and polysaccharides may be used as basic building blocks for the assembly of S-layer supported lipid membranes. These biomimetic membrane systems are distinguished by a nanopatterned fluidity, enhanced stability and longevity and thus, provide a dedicated reconstitution matrix for membrane-active peptides and transmembrane proteins. Exciting areas for application of composite S-layer membrane systems concern sensor systems involving specific membrane functions. PMID:19303933

  2. Single Molecule Probes of Lipid Membrane Structure

    E-print Network

    Livanec, Philip W.

    2009-12-14

    -M) using p-polarized excitation can reveal single-molecule orientations when spherical aberrations are introduced into the optics train. This approach was used here to measure the orientation of fluorescent lipid analogs doped into Langmuir...

  3. Lipid droplet dynamics in budding yeast.

    PubMed

    Wang, Chao-Wen

    2015-07-01

    Eukaryotic cells store excess fatty acids as neutral lipids, predominantly triacylglycerols and sterol esters, in organelles termed lipid droplets (LDs) that bulge out from the endoplasmic reticulum. LDs are highly dynamic and contribute to diverse cellular functions. The catabolism of the storage lipids within LDs is channeled to multiple metabolic pathways, providing molecules for energy production, membrane building blocks, and lipid signaling. LDs have been implicated in a number of protein degradation and pathogen infection processes. LDs may be linked to prevalent human metabolic diseases and have marked potential for biofuel production. The knowledge accumulated on LDs in recent years provides a foundation for diverse, and even unexpected, future research. This review focuses on recent advances in LD research, emphasizing the diverse physiological roles of LDs in the model system of budding yeast. PMID:25894691

  4. 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

  5. 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

  6. Coalescence Kinetics of Lipid Based Bicelles

    NASA Astrophysics Data System (ADS)

    Hu, Andrew; Fan, Tai-Hsi; Katsaras, John; Xia, Yan; Li, Ming; Nieh, Mu-Ping

    2014-03-01

    Uniform nanodisc can be self-assembled from lipid mixtures of dimyristoyl phosphatidylcholine (DMPC), dimyristoyl phosphatidylglycerol (DMPG), and dihexanoyl phosphatidylcholine (DHPC). This study focuses on the theoretical and experimental growth kinetics of phospholipid based nanodiscs. Motivation for this project comes from the nanodisc's small size and their potential use as a carrier for drug delivery. It was observed that at high total lipid concentration the nanodiscs are stable at approximately 10 nm. However, growth of these nanodiscs is observed at relatively low total lipid concentrations. Dynamic light scattering (DLS) is used to monitor the size and growth rate of these nanodiscs at different solution conditions. The growth at low concentrations is caused by to the transfer of charged lipid (DMPG) from the discs to the solution, reducing the Columbic interaction. The growth of nanodisc as a function of size and surface potential is modeled using the Smoluchowski transport equation with transport-limited boundary conditions.

  7. 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

  8. Structural Study of Lipid-binding Proteins 

    E-print Network

    Tsai, Han-Chun

    2013-08-09

    environment lacks sufficient nutrients, such as inside the macrophage, mycobacteria will enter a dormant (non-replicative) state that causes a re-routing of carbon flow in the tricarboxylic acid (TCA) cycle [8]. For aerobic organisms, the TCA cycle..., but also are used for sending signals inside and outside the bacteria. This expands the purpose of lipid binding from cellular metabolism to extracellular signaling, which is related to lipid recognition. There are proteins in host immune systems...

  9. 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

  10. Preparation of bovine lipid-free hemoglobin

    Microsoft Academic Search

    Dong-Xu Zhao; Xin-Gui Wei; Zhenyu Gu; Gui-Feng Zhang; Zhi-Guo Su

    2003-01-01

    A new method for preparation of Hb solution free of stromal lipid was described. Almost all the lipid in fresh hemolysate of bovine red blood was removed with hydrophobic interaction chromatography (HIC) in the presence of 2% PEG4000, 5% PEG4000, 2%PEG10000 or 5%PEG10000. With the adding of 5%PEG4000, the 80% of recovery of Hb in HIC was obtained and the

  11. Hedgehog Signaling: A Tale of Two Lipids

    NSDL National Science Digital Library

    Philip Ingham (University of Sheffield; Medical Research Council (MRC) Intercellular Signalling Group, Centre for Developmental Genetics, School of Medicine and Biomedical Science)

    2001-11-30

    Hedgehog proteins constitute one of the major classes of intercellular signals that control inductive interactions during animal development. These proteins undergo unusual lipid modifications and signal through an unconventional transmembrane protein receptor that is characterized by a sequence motif implicated in sterol sensing. Recent studies suggest that the lipid adducts regulate the range and potency of the signals, whereas the sterol-sensing domain is essential for receptor activity.

  12. Lipids of the Plant Plasma Membrane

    Microsoft Academic Search

    Fabienne Furt; Françoise Simon-Plas; Sébastien Mongrand

    \\u000a The plasma membrane (PM) is arguably the most diverse membrane of the plant cell. Furthermore, the protein and lipid composition\\u000a of the PM varies with cell type, developmental stage, and environment. Physical properties of lipids and associate proteins\\u000a allow the formation of a barrier that is selectively permeable to macromolecules and solutes. As the plasma membrane delineates\\u000a the interface between

  13. Membrane Cholesterol, Protein Phosphorylation, and Lipid Rafts

    NSDL National Science Digital Library

    Michael Edidin (Johns Hopkins University; Department of Biology REV)

    2001-01-30

    The functions of cholesterol and membrane microdomains in transmembrane signaling remain controversial. Edidin discusses the questions surrounding lipid rafts, membrane microdomains that have been biochemically defined but are difficult to visualize in vivo. He also discusses whether experiments showing correlation of changes in plasma membrane cholesterol with differentiation and the formation of adherens junctions in endothelial cells are consistent with a model in which lipid rafts influence the regulation of these processes.

  14. Lipid oxidation products and chick nutritional encephalopathy

    Microsoft Academic Search

    P. Budowski; I. Bartov; Y. Dror; E. N. Frankel

    1979-01-01

    Safflower oil and its distilled methyl esters were thermally oxidized and fed to young chicks in a vitamin E deficient diet.\\u000a At a dietary level of 10%, the oxidized lipids caused more severe nutritional encephalopathy (NE) than the unoxidized methyl\\u000a esters, indicating that factors other than dietary linoleic acid and vitamin E affect the development of NE. A polar lipid

  15. Hexadecylphosphocholine interaction with lipid monolayers.

    PubMed

    Rakotomanga, Michaëlle; Loiseau, Philippe M; Saint-Pierre-Chazalet, Michčle

    2004-03-01

    The phospholipid analogue miltefosine or hexadecylphosphocholine (HePC) is a drug of high interest in the treatment for fatal visceral leishmaniasis (VL) due to Leishmania donovani particularly because of its activity by oral route. In this study, the interaction of HePC with a monolayer of beta-palmitoyl-gamma-oleyl-phosphatidylcholine (POPC) as membrane model or sterol (ergosterol or cholesterol) was investigated. At a constant pressure of 25 mN/m, the adsorption kinetics of HePC into the monolayers showed that HePC molecules are inserted into the monolayer of lipids as monomers until the critical micellar concentration (CMC). At HePC concentrations superior to the CMC, the micelles of HePC are deployed at the interface as groups of monomers into the POPC or sterol monolayer. The study of mixture of HePC/(POPC or sterol), spread at the air-water interface, shows that a simple miscibility between HePC and POPC is observed, whereas a high condensation appears between HePC and sterols showing a high affinity between HePC and sterols. In addition, HePC does not act as detergent disturbing membrane integrity. PMID:15003884

  16. 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

  17. Lipids and cell death in yeast

    PubMed Central

    Eisenberg, Tobias; Büttner, Sabrina

    2014-01-01

    Understanding lipid-induced malfunction represents a major challenge of today's biomedical research. The connection of lipids to cellular and organ dysfunction, cell death, and disease (often referred to as lipotoxicity) is more complex than the sole lipotoxic effects of excess free fatty acids and requires genetically tractable model systems for mechanistic investigation. We herein summarize recent advances in the field of lipid-induced toxicity that employ the established model system for cell death and aging research of budding yeast Saccharomyces cerevisiae. Studies in yeast have shed light on various aspects of lipotoxicity, including free fatty acid toxicity, sphingolipid-modulated cell death as well as the involvement of cardiolipin and lipid peroxidation in the mitochondrial pathways of apoptosis. Regimens used range from exogenously applied lipids, genetic modulation of lipolysis and triacylglyceride synthesis, variations in sphingolipid/ceramide metabolism as well as changes in peroxisome function by either genetic or pharmacological means. In future, the yeast model of programmed cell death will further contribute to the clarification of crucial questions of lipid-associated malfunction. PMID:24119111

  18. S-layer stabilized lipid membranes (Review)

    PubMed Central

    Schuster, Bernhard; Pum, Dietmar; Sleytr, Uwe B.

    2010-01-01

    The present review focuses on a unique bio-molecular construction kit based on surface-layer (S-layer) proteins as building blocks and patterning elements, but also major classes of biological molecules such as lipids, membrane-active peptides and membrane proteins, and glycans for the design of functional supported lipid membranes. The biomimetic approach copying the supramolecular building principle of most archaeal cell envelopes merely composed of a plasma membrane and a closely associated S-layer lattice has resulted in robust and fluid lipid membranes. Most importantly, S-layer supported lipid membranes spanning an aperture or generated on solid and porous substrates constitute highly interesting model membranes for the reconstitution of responsive transmembrane proteins and membrane-active peptides. This is of particular challenge as one-third of all proteins are membrane proteins such as pore-forming proteins, ion channels, and receptors. S-layer supported lipid membranes are seen as one of the most innovative strategies in membrane protein-based nanobiotechnology with potential applications that range from pharmaceutical (high-throughput) drug screening over lipid chips to the detection of biological warfare agents. PMID:20408666

  19. 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

  20. Rhodopsin-lipid interactions studied by NMR.

    PubMed

    Soubias, Olivier; Gawrisch, Klaus

    2013-01-01

    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 500cm(2) 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 (2)H NMR order parameter measurements, it is detected that rhodopsin insertion elastically deforms membranes near the protein. Furthermore, by (1)H saturation-transfer NMR under conditions of magic angle spinning, 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

  1. 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

  2. Studying lipid-protein interactions with electron paramagnetic resonance spectroscopy of spin-labeled lipids.

    PubMed

    Páli, Tibor; Kóta, Zoltán

    2013-01-01

    Spin label electron paramagnetic resonance (EPR) of lipid-protein interactions reveals crucial features of the structure and assembly of integral membrane proteins. Spin label EPR spectroscopy is the technique of choice to characterize the protein-solvating lipid shell in its highly dynamic nature, because the EPR spectra of lipids that are spin labeled close to the terminal methyl end of their acyl chains display two spectral components, those corresponding to lipids directly contacting the protein and those corresponding to lipids in the bulk fluid bilayer regions of the membrane. In this chapter, typical spin label EPR procedures are presented that allow determination of the stoichiometry of interaction of spin-labeled lipids with the intra-membranous region of membrane proteins or polypeptides, as well as the association constant of the spin-labeled lipid with respect to the host lipid. The lipids giving rise to the so-called immobile spectral component in the EPR spectrum of such samples are identified as the motionally restricted first-shell lipids solvating membrane proteins in biomembranes. Stoichiometry and selectivity are directly related to the structure of the intra-membranous sections of membrane-associated proteins or polypeptides and can be used to study the state of assembly of such proteins in the membrane. Since these characteristics of lipid-protein interactions are discussed in detail in the literature [see Marsh (Eur Biophys J 39:513-525, 2010) for a most recent review], here we focus more on how to spin label model and biomembranes and how to measure and analyze the two-component EPR spectra of spin-labeled lipids in phospholipid bilayers that contain proteins or polypeptides. After a description of how to prepare spin-labeled model and native biological membranes, we present the reader with computational procedures for determining the molar fraction of motionally restricted lipids when both, one, or none of the pure isolated-mobile or immobile-spectral components are available. With these topics, this chapter complements a recent methodological paper [Marsh (Methods 46:83-96, 2008)]. The interpretation of the data is discussed briefly, as well as other relevant and recent spin label EPR techniques for studying lipid-protein interactions, not only from the point of view of lipid chain dynamics. PMID:23404282

  3. Identification of lipids and lipid-binding proteins in phloem exudates from Arabidopsis thaliana

    PubMed Central

    Guelette, Brandon S.; Benning, Urs F.; Hoffmann-Benning, Susanne

    2012-01-01

    The phloem plays a crucial role in assimilate and nutrient transport, pathogen response, and plant growth and development. Yet, few species have yielded pure phloem exudate and, if proteins need to be analysed, those species may not have sequenced genomes, making identification difficult. The enrichment of Arabidopsis thaliana phloem exudate in amounts large enough to allow for metabolite and protein analysis is described. Using this method, it was possible to identify 65 proteins present in the Arabidopsis phloem exudate. The majority of these proteins could be grouped by response to pathogens, stress, or hormones, carbon metabolism, protein interaction, modification, and turnover, and transcription factors. It was also possible to detect 11 proteins that play a role in lipid/fatty acid metabolism (aspartic protease, putative 3-?-hydroxysteroid dehydrogenase, UDP-sulphoquinovose synthase/SQD1, lipase, PIG-P-like protein: phosphatidylinositol-N-acetylglucosaminyltransferase), storage (glycine-rich protein), binding (annexin, lipid-associated family protein, GRP17/oleosin), and/or signalling (annexin, putative lipase, PIG-P-like protein). Along with putative lipid-binding proteins, several lipids and fatty acids could be identified. Only a few examples exist of lipids (jasmonic acid, oxylipins) or lipid-binding proteins (DIR1, acyl-CoA-binding protein) in the phloem. Finding hydrophobic compounds in an aqueous environment is not without precedence in biological systems: human blood contains a variety of lipids, many of which play a significant role in human health. In blood, lipids are transported while bound to proteins. The present findings of lipids and lipid-binding proteins in phloem exudates suggest that a similar long-distance lipid signalling exists in plants and may play an important role in plant growth and development. PMID:22442409

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

    PubMed

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

    2011-11-01

    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 E. 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

  5. Role of phosphatidylethanolamine lipids in the stabilization of protein-lipid contacts

    Microsoft Academic Search

    Suzanne Scarlata; Sol M. Gruner

    1997-01-01

    We have investigated the effect of lipids with phosphatidylethanolamine (PE) head groups on the stabilization of contacts between the tryptophan side chains of gramicidin and the lipid head groups. We initially developed two fluorescence methods that can be correlated to the spontaneous curvature of DOPC\\/DOPE and DOPC\\/DOPEme. One is based on bilayer structure and measures the rotational motion of a

  6. Lipid transfer protein transports compounds from lipid nanoparticles to plasma lipoproteins.

    PubMed

    Seki, Junzo; Sonoke, Satoru; Saheki, Akira; Koike, Tomohiro; Fukui, Hiroshi; Doi, Masaharu; Mayumi, Tadanori

    2004-05-01

    Nanometer-sized lipid emulsion particles with a diameter of 25-50 nm, called Lipid Nano-Sphere (LNS), are expected as a promising drug carrier to show prolonged plasma half-life of an incorporating drug. In terms of successful drug delivery using LNS, a drug should be incorporated into the lipid particles and remain within the particle, not only in the formulation in vitro but also after administration into the systemic blood circulation. In this study, we showed that phospholipids and some water-insoluble molecules also moved from lipid particles to plasma lipoproteins or albumin in serum and plasma half-lives of these compounds did not reflect that of the drug carriers. It was suggested that phospholipid or its derivative were transferred from LNS particles to plasma lipoproteins by lipid transfer proteins (LTP) in the circulation. These phenomena leaded to unsuccessful delivery of the drug with lipid-particulate drug carriers. On the other hand, lipophilic derivatives with cholesterol pro-moiety tested in this study were not released from LNS particles and showed prolonged plasma half-lives. Lipophilicity is known to be an important parameter for incorporating drugs into lipid particles but substrate specificity for LTP seems to be another key to success promising drug design using lipid emulsion particulate delivery system. PMID:15081154

  7. Lipid Clustering Correlates with Membrane Curvature as Revealed by Molecular Simulations of Complex Lipid Bilayers

    PubMed Central

    Koldsř, Heidi; Shorthouse, David; Hélie, Jean; Sansom, Mark S. P.

    2014-01-01

    Cell membranes are complex multicomponent systems, which are highly heterogeneous in the lipid distribution and composition. To date, most molecular simulations have focussed on relatively simple lipid compositions, helping to inform our understanding of in vitro experimental studies. Here we describe on simulations of complex asymmetric plasma membrane model, which contains seven different lipids species including the glycolipid GM3 in the outer leaflet and the anionic lipid, phosphatidylinositol 4,5-bisphophate (PIP2), in the inner leaflet. Plasma membrane models consisting of 1500 lipids and resembling the in vivo composition were constructed and simulations were run for 5 µs. In these simulations the most striking feature was the formation of nano-clusters of GM3 within the outer leaflet. In simulations of protein interactions within a plasma membrane model, GM3, PIP2, and cholesterol all formed favorable interactions with the model ?-helical protein. A larger scale simulation of a model plasma membrane containing 6000 lipid molecules revealed correlations between curvature of the bilayer surface and clustering of lipid molecules. In particular, the concave (when viewed from the extracellular side) regions of the bilayer surface were locally enriched in GM3. In summary, these simulations explore the nanoscale dynamics of model bilayers which mimic the in vivo lipid composition of mammalian plasma membranes, revealing emergent nanoscale membrane organization which may be coupled both to fluctuations in local membrane geometry and to interactions with proteins. PMID:25340788

  8. 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

  9. Lipid Membrane Adhesion and Fusion Driven by Designed, Minimally Multivalent Hydrogen-Bonding Lipids

    E-print Network

    Bong, Dennis

    Lipid Membrane Adhesion and Fusion Driven by Designed, Minimally Multivalent Hydrogen-Bonding) and melamine (M) functionalized lipids can form membranes that exhibit robust hydrogen-bond driven surface bonding when incorporated at 0.1-5 mol percent in fluid phospholipid membranes, inducing both vesicle

  10. Lipid Bilayers Covalently Anchored to Carbon Nanotubes

    PubMed Central

    Dayani, Yasaman; Malmstadt, Noah

    2012-01-01

    The unique physical and electrical properties of carbon nanotubes make them an exciting material for applications in various fields such as bioelectronics and biosensing. Due to the poor water solubility of carbon nanotubes, functionalization for such applications has been a challenge. Of particular need are functionalization methods for integrating carbon nanotubes with biomolecules and constructing novel hybrid nanostructures for bionanoelectronic applications. We present a novel method for the fabrication of dispersible, biocompatible carbon nanotube-based materials. Multi-walled carbon nanotubes (MWCNTs) are covalently modified with primary amine-bearing phospholipids in a carbodiimide-activated reaction. These modified carbon nanotubes have good dispersibility in nonpolar solvents. Fourier transform infrared (FTIR) spectroscopy shows peaks attributable to the formation of amide bonds between lipids and the nanotube surface. Simple sonication of lipid-modified nanotubes with other lipid molecules leads to the formation of a uniform lipid bilayer coating the nanotubes. These bilayer-coated nanotubes are highly dispersible and stable in aqueous solution. Confocal fluorescence microscopy shows labeled lipids on the surface of bilayer-modified nanotubes. Transmission electron microscopy (TEM) shows the morphology of dispersed bilayer-coated MWCNTs. Fluorescence quenching of lipid-coated MWCNTs confirms the bilayer configuration of the lipids on the nanotube surface and fluorescence anisotropy measurements show that the bilayer is fluid above the gel-to-liquid transition temperature. The membrane protein ?-hemolysin spontaneously inserts into the MWCNT-supported bilayer, confirming the biomimetic membrane structure. These biomimetic nanostructures are a promising platform for the integration of carbon nanotube-based materials with biomolecules. PMID:22568448

  11. Somnogenic activities of synthetic lipid A.

    PubMed Central

    Cady, A B; Kotani, S; Shiba, T; Kusumoto, S; Krueger, J M

    1989-01-01

    Bacterial infections and various immune response modifiers, including endotoxin and its lipid A moiety, alter sleep duration. The purpose of this study is to amplify our understanding of lipid A structure-somnogenic-pyrogenic activity relationships. Four synthetic disaccharide analogs of lipid A (LA-15-PP, LA-15-PH, LA-16-PH, and LA-18-PP) and a biosynthetic monosaccharide analog of lipid A (lipid X) were tested in rabbits for their effects on slow-wave sleep, rapid-eye-movement sleep, electroencephalographic slow-wave (0.5- to 4.0-Hz) amplitudes, and brain-colonic temperatures. Substances were injected intravenously and intracerebroventricularly. Compound LA-15-PP was the most potent; it significantly increased slow-wave sleep, delta electroencephalographic amplitudes, and brain-colonic temperatures while reducing rapid-eye-movement sleep. Compound LA-15-PH (monophosphoryl analog of LA-15-PP) induced effects similar to those of LA-15-PP, although the responses were weaker. Compound LA-18-PP induced increases in slow-wave sleep and delta amplitudes only after high doses, whereas compound LA-16-PH was devoid of these activities at the doses tested. Intracerebroventricular, but not intravenous, injections of lipid X induced small but significant increases in both slow-wave sleep and rapid-eye-movement sleep without affecting delta amplitudes or brain-colonic temperatures. These data suggest that the somnogenic actions of these lipid A analogs depend on the acylation or phosphorylation pattern and backbone structures of the molecules. Their soporific activities parallel their relative behaviors in other biological assays. PMID:2912895

  12. Phase Behavior of Mixed Lipid Bilayered System

    NSDL National Science Digital Library

    Rodriguez-Rivera, Veronica

    2005-01-01

    Lipid mixtures of short and long amphiphile chains self-assemble in water to form a great variety of structures. The morphology of these structures include phases composed of extended flexible bilayer membrane that may display order by stacking with a periodicity as in the anisotropic lamellar phase, or they may also form bilayered miscelles (or bicelles), bilayered disks formed of a long lipid chain with their edges stabilized by short chain lipid, with diameter of a few hundred angstroms. The lipid mixtures have a great potential in the study of membrane proteins and peptides. These mixtures imitate the physical properties of biological membranes and they are stable over a wide range of temperatures, pH and ionic strength. By having a detailed description of the morphology of the lipid mixtures and understanding their phases will help increase their use in various structural biology techniques. Our goal was to study the effect on transition between the bicelle to lamellar phase by changing the concentration of lipid in the solution. Each sample consisted of molar ratios of DHPC:DMPC:DMPG of 0.2:1:0.067. The concentration of lipid was of 20%, 10% and 5%. The 20% sample has a liquid to gel phase transition temperature of near 25°C. The lamellar phase forms above 25°C. By lowering the sample’s concentration and by an isotropic substitution of H2O by D2O, we found some intriguing results: the liquid to gel phase transition and lamellar phase temperature shifted. SANS, reflectometry and crossed polarizers were use to study the transition between the bicelle to lamellar phase. With these results, the structure of the phase boundary between the bicelles and lamellar morphology was better understood and characterized.

  13. Acquisition of membrane lipids by differentiating glyoxysomes: role of lipid bodies

    PubMed Central

    1991-01-01

    Glyoxysomes in cotyledons of cotton (Gossypium hirsutum, L.) seedlings enlarge dramatically within 48 h after seed imbibition (Kunce, C.M., R.N. Trelease, and D.C. Doman. 1984. Planta (Berl.). 161:156-164) to effect mobilization of stored cotton-seed oil. We discovered that the membranes of enlarging glyoxysomes at all stages examined contained a large percentage (36-62% by weight) of nonpolar lipid, nearly all of which were triacylglycerols (TAGs) and TAG metabolites. Free fatty acids comprised the largest percentage of these nonpolar lipids. Six uncommon (and as yet unidentified) fatty acids constituted the majority (51%) of both the free fatty acids and the fatty acids in TAGs of glyoxysome membranes; the same six uncommon fatty acids were less than 7% of the acyl constituents in TAGs extracted from cotton-seed storage lipid bodies. TAGs of lipid bodies primarily were composed of palmitic, oleic, and linoleic acids (together 70%). Together, these three major storage fatty acids were less than 10% of both the free fatty acids and fatty acids in TAGs of glyoxysome membranes. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) constituted a major portion of glyoxysome membrane phospholipids (together 61% by weight). Pulse-chase radiolabeling experiments in vivo clearly demonstrated that 14C-PC and 14C-PE were synthesized from 14C-choline and 14C-ethanolamine, respectively, in ER of cotyledons, and then transported to mitochondria; however, these lipids were not transported to enlarging glyoxysomes. The lack of ER involvement in glyoxysome membrane phospholipid synthesis, and the similarities in lipid compositions between lipid bodies and membranes of glyoxysomes, led us to formulate and test a new hypothesis whereby lipid bodies serve as the dynamic source of nonpolar lipids and phospholipids for membrane expansion of enlarging glyoxysomes. In a cell-free system, 3H-triolein (TO) and 3H- PC were indeed transferred from lipid bodies to glyoxysomes. 3H-PC, but not 3H-TO, also was transferred to mitochondria in vitro. The amount of lipid transferred increased linearly with respect to time and amount of acceptor organelle protein, and transfer occurred only when lipid body membrane proteins were associated with the donor lipid bodies. 3H-TO was transferred to and incorporated into glyoxysome membranes, and then hydrolyzed to free fatty acids. 3H-PC was transferred to and incorporated into glyoxysome and mitochondria membranes without subsequent hydrolysis. Our data are inconsistent with the hypothesis that ER contributes membrane lipids to glyoxysomes during postgerminative seedling growth.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1955468

  14. 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

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

    PubMed

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

    2014-09-26

    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

  16. 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

  17. 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.

  18. Lipid-modifying therapy in the elderly

    PubMed Central

    Hamilton-Craig, Ian; Colquhoun, David; Kostner, Karam; Woodhouse, Stan; d’Emden, Michael

    2015-01-01

    Cardiovascular disease (CVD) mortality and morbidity increases with increasing age, largely as a result of increased lifetime exposure as well as increased prevalence of CVD risk factors. Hospitalization for CVD increases by a factor of over 18× for those aged 85+ years versus those aged <30 years. In spite of this, life expectancy continues to increase, and in Australia for people reaching the age of 65 years, it is now 84 years in men and 87 years in women. The number of people for whom lipid management is potentially indicated therefore increases with aging. This is especially the case for secondary prevention and for people aged 65–75 years for whom there is also evidence of benefit from primary prevention. Many people in this age group are not treated with lipid-lowering drugs, however. Even those with CVD may be suboptimally treated, with one study showing treatment rates to fall from ~60% in those aged <50 years to <15% for those aged 85+ years. Treatment of the most elderly patient groups remains controversial partly from the lack of randomized trial intervention data and partly from the potential for adverse effects of lipid therapy. There are many complex issues involved in the decision to introduce effective lipid-lowering therapy and, unfortunately, in many instances there is not adequate data to make evidence-based decisions regarding management. This review summarizes the current state of knowledge of the management of lipid disorders in the elderly and proposes guidelines for management. PMID:25999729

  19. Integral hair lipid in human hair follicle.

    PubMed

    Lee, Won-Soo

    2011-12-01

    Integral hair lipid (IHL) is bound to the keratinized cell surface to make an environmentally resistant lipid envelope. It is mainly positioned on the hair cuticle and inner root sheath. IHL in the hair follicle may regard as hair barrier to be similar to the epidermal lipid layer functioning as skin barrier. Major constituents of IHL are fatty acid, phytosphingosine, ceramide in decreasing order. Minor constituents of IHL are cholesterol, cholesterol sulfate and cholesterol oleate. Cuticle or cortical cell surface in hair are abundant in fatty acids unlike the keratinized area of epidermis or sebaceous gland, and about 30-40% of such fatty acids are composed of 18-methyl-eicosanoic acid which is known to be bound to proteins by ester or thioester bond. Various factors including moisture, solvent, oxidative damage during bleaching or permanent waving affect IHL. Photochemical changes also can occur in IHL as well as in hair protein and hair pigment. Lipid metabolism is thought to play an essential role in lipid envelope of hair, but also involvement in hair development and function. PMID:21906914

  20. 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

  1. In vitro systems for Atg8 lipidation.

    PubMed

    Zens, Bettina; Sawa-Makarska, Justyna; Martens, Sascha

    2015-03-01

    Macroautophagy is a major bulk degradation pathway for cytoplasmic material in eukaryotic cells. During macroautophagy, double membrane-bound organelles called autophagosomes are formed in a de novo manner. In the course of their formation autophagosomes capture cytoplasmic material, which is subsequently degraded upon fusion with the lysosomal system in complex eukaryotes or the vacuole in yeast. Several proteins are required for autophagosome formation. Among these are the components of two ubiquitin-like conjugation reactions that collectively mediate the conjugation of the ubiquitin-like Atg12 to the Atg5 protein and of the ubiquitin-like protein Atg8 to the headgroup of the membrane lipid phosphatidylethanolamine. The lipidated form of Atg8 is membrane-bound and marks the growing autophagosomal membrane as well as the completed autophagosome. Here we describe assays for the in vitro reconstitution of the Atg8 lipidation reaction using recombinantly expressed and purified proteins derived from Saccharomycescerevisiae in combination with small and giant unilamellar vesicles. The assays enable the study of the biochemical mechanisms of action of the Atg8 lipidation machinery and to analyze the impact of mutations and post-translational modifications of the conjugation machinery on Atg8 lipidation. PMID:25461810

  2. Circadian regulators of intestinal lipid absorption.

    PubMed

    Hussain, M Mahmood; Pan, Xiaoyue

    2015-04-01

    Among all the metabolites present in the plasma, lipids, mainly triacylglycerol and diacylglycerol, show extensive circadian rhythms. These lipids are transported in the plasma as part of lipoproteins. Lipoproteins are synthesized primarily in the liver and intestine and their production exhibits circadian rhythmicity. Studies have shown that various proteins involved in lipid absorption and lipoprotein biosynthesis show circadian expression. Further, intestinal epithelial cells express circadian clock genes and these genes might control circadian expression of different proteins involved in intestinal lipid absorption. Intestinal circadian clock genes are synchronized by signals emanating from the suprachiasmatic nuclei that constitute a master clock and from signals coming from other environmental factors, such as food availability. Disruptions in central clock, as happens due to disruptions in the sleep/wake cycle, affect intestinal function. Similarly, irregularities in temporal food intake affect intestinal function. These changes predispose individuals to various metabolic disorders, such as metabolic syndrome, obesity, diabetes, and atherosclerosis. Here, we summarize how circadian rhythms regulate microsomal triglyceride transfer protein, apoAIV, and nocturnin to affect diurnal regulation of lipid absorption. PMID:25057097

  3. Mobility of DNA on supported lipid bilayers

    NASA Astrophysics Data System (ADS)

    Padala, Chakradhar; Cole, Richard; Kumar, Sanat; Kane, Ravi

    2006-03-01

    Extensive theoretical ideas have been developed to understand the transport properties of transmembrane proteins in the lipid bilayer. However, of late, there has been a rising interest in understanding the transport properties of non-compact macromolecules strongly adsorbed ``on'' and not incorporated into lipid bilayers in light of the relevance for designing improved DNA separation strategies and for gene therapy. Previously, researchers like Radler et al. have suggested that such strongly adsorbed polymers can be treated similar to a polymer in a two-dimensional fluid, but there exists no experimental proof to date. In order to test this hypothesis and also to gain a better understanding of polymer dynamics in two dimensions, we studied the lateral transport of a short, single stranded DNA oligonucleotide adsorbed on a supported cationic lipid bilayer. Fluorescence Recovery After Photobleaching (FRAP) analysis reveals that diffusivity of the adsorbed DNA quantitatively tracks that of the underlying lipid. These results, along with the comparison between our results for short, non-compact adsorbed biopolymers and those reported for globular proteins incorporated into the lipid bilayer will be discussed.

  4. 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

  5. mitochondrial pathway for biosynthesis of lipid mediators

    PubMed Central

    Tyurina, Yulia Y.; Poloyac, Samuel M.; Tyurin, Vladimir A.; Kapralov, Alexander A.; Jiang, Jianfei; Anthonymuthu, Tamil Selvan; Kapralova, Valentina I.; Vikulina, Anna S.; Jung, Mi-Yeon; Epperly, Michael W.; Mohammadyani, Dariush; Klein-Seetharaman, Judith; Jackson, Travis C.; Kochanek, Patrick M.; Pitt, Bruce R.; Greenberger, Joel S.; Vladimirov, Yury A.; Bay?r, Hülya; Kagan, Valerian E.

    2014-01-01

    The central role of mitochondria in metabolic pathways and in cell death mechanisms requires sophisticated signaling systems. Essential in this signaling process is an array of lipid mediators derived from polyunsaturated fatty acids. However, the molecular machinery for the production of oxygenated polyunsaturated fatty acids is localized in the cytosol and their biosynthesis has not been identified in mitochondria. Here we report that a range of diversified polyunsaturated molecular species derived from a mitochondria-specific phospholipid, cardiolipin, are oxidized by the intermembrane space hemoprotein, cytochrome c. We show that an assortment of oxygenated cardiolipin species undergoes phospholipase A2-catalyzed hydrolysis thus generating multiple oxygenated fatty acids, including well known lipid mediators. This represents a new biosynthetic pathway for lipid mediators. We demonstrate that this pathway including oxidation of polyunsaturated cardiolipins and accumulation of their hydrolysis products – oxygenated linoleic, arachidonic acids and monolyso-cardiolipins – is activated in vivo after acute tissue injury. PMID:24848241

  6. Peptide-Lipid Interactions: Experiments and Applications

    PubMed Central

    Galdiero, Stefania; Falanga, Annarita; Cantisani, Marco; Vitiello, Mariateresa; Morelli, Giancarlo; Galdiero, Massimiliano

    2013-01-01

    The interactions between peptides and lipids are of fundamental importance in the functioning of numerous membrane-mediated cellular processes including antimicrobial peptide action, hormone-receptor interactions, drug bioavailability across the blood-brain barrier and viral fusion processes. Moreover, a major goal of modern biotechnology is obtaining new potent pharmaceutical agents whose biological action is dependent on the binding of peptides to lipid-bilayers. Several issues need to be addressed such as secondary structure, orientation, oligomerization and localization inside the membrane. At the same time, the structural effects which the peptides cause on the lipid bilayer are important for the interactions and need to be elucidated. The structural characterization of membrane active peptides in membranes is a harsh experimental challenge. It is in fact accepted that no single experimental technique can give a complete structural picture of the interaction, but rather a combination of different techniques is necessary. PMID:24036440

  7. Open questions in lipid droplet biology.

    PubMed

    Ohsaki, Yuki; Suzuki, Michitaka; Fujimoto, Toyoshi

    2014-01-16

    Lipid droplets (LDs) have been the focus of intense research for the past decade because of their active engagement in lipid metabolism and relationship with diseases. In contrast to other intracellular organelles, LDs are composed of a mass of hydrophobic lipid esters that is covered with a phospholipid monolayer. The unique architecture makes the LD a formidable object to study by the methods available today, and many fundamental questions remain unanswered. This review focuses on some of those questions, such as how LDs form and grow, how proteins move to and from LDs, and how LDs are related to protein degradation; we will also discuss what is not known about LDs. We think that small LDs that have thus far eluded analysis are the key to resolving many of the above-mentioned questions. PMID:24239006

  8. 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.

  9. Conformational changes of ?2-human glycoprotein I and lipid order in lipid-protein complexes.

    PubMed

    Paolorossi, Mariana; Montich, Guillermo G

    2011-09-01

    We studied the conformation of ?2-human glycoprotein (?2GPI) in solution and bound to the anionic lipids palmitoyl oleoyl phosphatidylglycerol (POPG), dimiristoyl phosphatidylglycerol (DMPG) and dipalmitoyl phosphatidylglycerol (DPPG) as a function of the temperature. We used the infrared amide I' band to study the protein conformation, and the position of the antisymmetric stretching band of the methylene groups in the lipid hydrocarbon chains to study the lipid order. Lipid-protein complexes were studied in media of low and high ionic strengths. In solution, ?2GPI displayed a conformational pre-transition in the range 47-50°C, characterized by a shift in the band of ? secondary structure, previous to the main unfolding at 64°C. When the protein was bound to the anionic lipid membranes at 25°C, a similar shift as in the pre-transition in solution was observed, together with an increase in the band corresponding to ?-helix secondary structure. Lipid-protein complexes formed large aggregates within the temperature range 10?60°C. At temperatures above the protein unfolding, the complexes were disrupted to yield vesicles with bound protein. This finding indicated that the native fold was required for the formation of the lipid-protein aggregates. Cycles of heating and cooling showed hysteresis in the formation of aggregates. PMID:21600190

  10. Clustering of ?-Synuclein on Supported Lipid Bilayers: Role of Anionic Lipid, Protein, and Divalent Ion Concentration

    PubMed Central

    Pandey, Anjan P.; Haque, Farzin; Rochet, Jean-Christophe; Hovis, Jennifer S.

    2009-01-01

    Abstract ?-Synuclein is the major component of Lewy body inclusions found in the brains of patients with Parkinson's disease. Several studies indicate that ?-synuclein binds to negatively charged phospholipid bilayers. We examined the binding of ?-synuclein to membranes containing different amounts of negatively charged lipids using supported lipid bilayers, epifluorescence microscopy, fluorescence recovery after photobleaching, and bulk fluorescence techniques. The membranes contained phosphatidylcholine and phosphatidylglycerol. In the absence of protein, these lipids mix uniformly. Our results show that the propensity of ?-synuclein to cluster on the membrane increases as the concentration of anionic lipid and/or protein increases. Regions on the lipid bilayer where ?-synuclein is clustered are enriched in phosphatidylglycerol. We also observe divalent metal ions stimulate protein cluster formation, primarily by promoting lipid demixing. The importance of protein structure, lipid demixing, and divalent ions, as well as the physiological implications, will be discussed. Because membrane-bound ?-synuclein assemblies may play a role in neurotoxicity, it is of interest to determine how membranes can be used to tune the propensity of ?-synuclein to aggregate. PMID:19167303

  11. 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

  12. Microsecond molecular dynamics simulations of lipid mixing.

    PubMed

    Hong, Chunkit; Tieleman, D Peter; Wang, Yi

    2014-10-14

    Molecular dynamics (MD) simulations of membranes are often hindered by the slow lateral diffusion of lipids and the limited time scale of MD. In order to study the dynamics of mixing and characterize the lateral distribution of lipids in converged mixtures, we report microsecond-long all-atom MD simulations performed on the special-purpose machine Anton. Two types of mixed bilayers, POPE:POPG (3:1) and POPC:cholesterol (2:1), as well as a pure POPC bilayer, were each simulated for up to 2 ?s. These simulations show that POPE:POPG and POPC:cholesterol are each fully miscible at the simulated conditions, with the final states of the mixed bilayers similar to a random mixture. By simulating three POPE:POPG bilayers at different NaCl concentrations (0, 0.15, and 1 M), we also examined the effect of salt concentration on lipid mixing. While an increase in NaCl concentration is shown to affect the area per lipid, tail order, and lipid lateral diffusion, the final states of mixing remain unaltered, which is explained by the largely uniform increase in Na(+) ions around POPE and POPG. Direct measurement of water permeation reveals that the POPE:POPG bilayer with 1 M NaCl has reduced water permeability compared with those at zero or low salt concentration. Our calculations provide a benchmark to estimate the convergence time scale of all-atom MD simulations of lipid mixing. Additionally, equilibrated structures of POPE:POPG and POPC:cholesterol, which are frequently used to mimic bacterial and mammalian membranes, respectively, can be used as starting points of simulations involving these membranes. PMID:25237736

  13. 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

  14. Lipid feeding and milk fat depression.

    PubMed

    Jenkins, Thomas C; Harvatine, Kevin J

    2014-11-01

    Diets fed to cattle contain mostly unsaturated fatty acids supplied in grains and forages, by-products, and fat supplements. Lipid intake by dairy cattle must be restricted to prevent alterations of microbial populations in the rumen that can negatively affect milk yield. Unsaturated fatty acids consumed by cattle are extensively metabolized through biohydrogenation, intermediates of which include conjugated linoleic acid (CLA) and trans-monoenoic acid isomers. Three specific CLA intermediates of biohydrogenation have been shown to cause milk fat depression in dairy cattle through coordinated suppression of mammary lipogenic genes by a transcription factor that is a central regulator of lipid synthesis. PMID:25239061

  15. Treatment of cocaine overdose with lipid emulsion.

    PubMed

    Jakkala-Saibaba, R; Morgan, P G; Morton, G L

    2011-12-01

    We describe the management and recovery of a 28-year-old man following a history of overdose by nasal inhalation of cocaine. The patient was presented in a comatose state suffering from seizures and marked cardiovascularly instability. Intravenous lipid emulsion was administered following initial resuscitation and tracheal intubation, as a means of treating persistent cardiac arrhythmias and profound hypotension. Following lipid emulsion therapy, the patient's life-threatening cardiovascular parameters rapidly improved and he recovered well without any side effects, thus being discharged within 2 days. PMID:22074030

  16. The mycobacterial cell envelope-lipids.

    PubMed

    Jackson, Mary

    2014-10-01

    Mycobacterium tuberculosis (Mtb) lipids are indelibly imprinted in just about every key aspect of tuberculosis (TB) basic and translational research. Although the interest in these compounds originally stemmed from their abundance, structural diversity, and antigenicity, continued research in this field has been driven by their important contribution to TB pathogenesis and their interest from the perspective of drug, vaccine, diagnostic, and biomarker development. This article summarizes what is known of the roles of lipids in the physiology and pathogenicity of Mtb and the exciting developments that have occurred in recent years in identifying new lead compounds targeting their biogenesis. PMID:25104772

  17. SERUM LIPID PROFILE IN SUICIDE ATTEMPTERS

    PubMed Central

    Verma, Sandeep; Trivedi, J.K.; Singh, H.; Dalal, P.K.; Asthana, O.P.; Srivastava, J.S.; Mishra, Rakesh; Ramakant; Sinha, P.K.

    1999-01-01

    Practical difficulties associated with assessment of central parameters necessitates the development of peripheral markers of suicidal risk. Recent research suggest that serum lipid profile may be a useful indicator of suicidal behaviour. Serum lipid profiles of forty suicide attempters were compared with forty age, sex and BMI matched controls. Total serum cholesterol, serum Triglyceride, LDL levels and HDL levels were found to be lower in suicide attempters but were not statistically significant. Statistically significant negative con-elation was seen between risk-rescue score and above mentioned parameters. No statitically significant difference was observed when various diagnostic break-up groups of patients were compared. PMID:21430801

  18. 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

  19. Alternative lipid mobilization: the insect shuttle system.

    PubMed

    van der Horst, Dick J; van Hoof, Dennis; van Marrewijk, Wil J A; Rodenburg, Kees W

    2002-10-01

    Lipid mobilization in long-distance flying insects has revealed a novel concept for lipid transport in the circulatory system during exercise. Similar to energy generation for sustained locomotion in mammals, the work accomplished by non-stop flight activity is powered by oxidation of free fatty acids (FFA) derived from endogenous reserves of triacylglycerol. The transport form of the lipid, however, is diacylglycerol (DAG), which is delivered to the flight muscles associated with lipoproteins. In the insect system, the multifunctional lipoprotein, high-density lipophorin (HDLp) is loaded with DAG while additionally, multiple copies of the exchangeable apolipoprotein, apoLp-III, associate with the expanding particle. As a result, lipid-enriched low-density lipophorin (LDLp) is formed. At the flight muscles, LDLp-carried DAG is hydrolyzed and FFA are imported into the muscle cells for energy generation. The depletion of DAG from LDLp results in the recovery of both HDLp and apoLp-III, HDLp, identified which are reutilized for another cycle of DAG transport. A receptor for as a novel member of the vertebrate low-density lipoprotein (LDL) receptor family, does not seem to be involved in the lipophorin shuttle mechanism operative during flight activity. In addition, endocytosis of HDLp mediated by the insect receptor does not seem to follow the classical mammalian LDL pathway. Many structural elements of the lipid mobilization system in insects are similar to those in mammals. Domain structures of apoLp-I and apoLp-II, the non-exchangeable apolipoprotein components of HDLp, are related to apoB 100. ApoLp-III is a bundle of five amphipathic alpha-helices that binds to a lipid surface very similar to the four-helix bundle of the N-terminal domain of human apoE. Despite these similarities, the functioning of the insect lipoprotein in energy transport during flight activity is intriguingly different, since the TAG-rich mammalian lipoproteins play no role as a carrier of mobilized lipids during exercise and besides, these lipoproteins are not functioning as a reusable shuttle for lipid transport. On the other hand, the deviant behavior of similar molecules in a different biological system may provide a useful alternative model for studying the molecular basis of processes related to human disorders and disease. PMID:12479576

  20. 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.

  1. Long and Short Lipid Molecules Experience the Same Interleaflet Drag in Lipid Bilayers

    PubMed Central

    Horner, Andreas; Akimov, Sergey A.; Pohl, Peter

    2015-01-01

    Membrane interleaflet viscosity ?e affects tether formation, phase separation into domains, cell shape changes, and budding. Contrary to the expected contribution to interleaflet coupling from interdigitation, the slide of lipid patches in opposing monolayers conferred the same value ?e ? 3×109 J s m?4 for the friction experienced by the ends of both short and long chain fluorescent lipid analogues. Consistent with the weak dependence of the translational diffusion coefficient on lipid length, the in-layer viscosity was, albeit length dependent, much smaller than ?e. PMID:23848924

  2. Long and Short Lipid Molecules Experience the Same Interleaflet Drag in Lipid Bilayers

    NASA Astrophysics Data System (ADS)

    Horner, Andreas; Akimov, Sergey A.; Pohl, Peter

    2013-06-01

    Membrane interleaflet viscosity ?e affects tether formation, phase separation into domains, cell shape changes, and budding. Contrary to the expected contribution to interleaflet coupling from interdigitation, the slide of lipid patches in opposing monolayers conferred the same value ?e?3×109Jsm-4 for the friction experienced by the ends of both short and long chain fluorescent lipid analogues. Consistent with the weak dependence of the translational diffusion coefficient on lipid length, the in-layer viscosity was, albeit length dependent, much smaller than ?e.

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

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...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...

  4. Lipid bilayer and cytoskeletal interactions in a red blood cell

    E-print Network

    Peng, Zhangli

    We study the biomechanical interactions between the lipid bilayer and the cytoskeleton in a red blood cell (RBC) by developing a general framework for mesoscopic simulations. We treated the lipid bilayer and the cytoskeleton ...

  5. Fluorescopic evaluation of protein-lipid relations in cellular signalling

    Microsoft Academic Search

    E. H. W. Pap

    1994-01-01

    IntroductionCellular communication is partly mediated through the modulation of protein activity, structure and dynamics by lipids. In contrast to the biochemical aspects of lipid signalling, relatively little is known about the physical properties of the \\

  6. MACROMOLECULES, Part 1* Carbohydrates, Lipids, and Nucleic Acids

    E-print Network

    Prestwich, Ken

    MACROMOLECULES, Part 1* Carbohydrates, Lipids, and Nucleic Acids Introduction: Living organisms are unique in being composed of long, massive molecules called macromolecules. Biochemistry, the study of macromolecules: carbohydrates, lipids, proteins and nucleic acids. All macromolecules are polymers (chains

  7. 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.

  8. MR-Visible Lipids and the Tumor Microenvironment

    PubMed Central

    Delikatny, E. James; Chawla, Sanjeev; Leung, Daniel-Joseph; Poptani, Harish

    2013-01-01

    MR-visible lipids or mobile lipids are defined as lipids that are observable using proton magnetic resonance spectroscopy in cells and in tissues. These MR-visible lipids are composed of triglycerides and cholesterol esters that accumulate in intracellular neutral lipid droplets, where their MR visibility is conferred as a result of the increased molecular motion available in this unique physical environment. This review will discuss factors that lead to the biogenesis of MR-visible lipids in cancer cells and in other cell types such as immune cells and fibroblasts. We focus on the accumulations of mobile lipids that are inducible in cultured cells by a number of stresses, including culture conditions and in response to activating stimuli or apoptotic cell death induced by anticancer drugs. This is compared with animal tumor models, where increases in mobile lipids are observed in response to chemo and radiotherapy, and to human tumors where mobile lipids are observed predominantly in high-grade brain tumors and in regions of necrosis. Conducive conditions for mobile lipid formation in the tumor microenvironment will be discussed including low pH, oxygen availability and the presence of inflammatory cells. It is concluded that MR-visible lipids appear in cancer cells and human tumors as a stress response. Mobile lipids stored as neutral lipid droplets may play a role in detoxification of the cell or act as an alternate energy source, especially in cancer cells, which often grow in ischemic/hypoxic environments. The role of MR-visible lipids in cancer diagnosis and assessment of treatment response both in animal models of cancer as well as human brain tumors will also be discussed. Although technical limitations exist in the accurate detection of intratumoral mobile lipids, early increases in mobile lipids after therapeutic interventions may be used as a potential biomarker for assessing treatment response in cancer. PMID:21538631

  9. Lipid-based Nanoparticles for Nucleic Acid Delivery

    Microsoft Academic Search

    Weijun Li; Francis C. Szoka Jr

    2007-01-01

    Abstract  Lipid-based colloidal particles have been extensively studied as systemic gene delivery carriers. The topic that we would\\u000a like to emphasize is the formulation\\/assembly of lipid-based nanoparticles (NP) with diameter under 100 nm for delivering\\u000a nucleic acid in vivo. NP are different from cationic lipid–nucleic acid complexes (lipoplexes) and are vesicles composed of lipids and encapsulated\\u000a nucleic acids with a diameter less

  10. Carbon fixation into lipid in small freshwater lakes

    Microsoft Academic Search

    BRUCE C. WAINMAN; DAVID R. S. LEAN

    1992-01-01

    Algal lipid is a critical food resource for zooplankton, a solvent for lipophilic contaminants, and a useful indicator of phytoplankton nutrient status in culture. Seasonal patterns in lipid production and the photosynthetic parameters describing lipid production were determined for three meso- trophic to oligotrophic, headwater lakes. The mean lipid fraction of C fixation (LFCF) was 15.8% (range 8.5-22.5%) measured bimonthly

  11. Lipids and the pathogenesis of pre-eclampsia

    Microsoft Academic Search

    N. Sattar; I. A. Greer

    1999-01-01

    This review summarizes evidence for the involvement of lipids in the pathophysiology of pre-eclampsia. The following areas are addressed: lipids and lipoprotein subfractions in pre-eclampsia set against a background of the lipid pattern seen in normal pregnancy; the potential mechanism(s) for such changes in pre-eclampsia; and potential links of the atherogenic lipid profile in pre-eclampsia to oxidative pathways, endothelial dysfunction

  12. Dietary ethanol and lipid synthesis in Drosophila melanogaster

    Microsoft Academic Search

    Billy W. Geer; Marilyn L. Langevin; Stephen W. McKechnie

    1985-01-01

    When cultured on a defined diet, ethanol was an efficient substrate for lipid synthesis in wild-type Drosophila melanogaster larvae. At certain dietary levels both ethanol and sucrose could displace the other as a lipid substrate. In wild-type larvae more than 90% of the flux from ethanol to lipid was metabolized via the alcohol dehydrogenase (ADH) system. The ADH and aldehyde

  13. Extraction of Lipids from Flax Processing Waste Using Hot Ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cuticle of flax stems contain lipids that provide a protective barrier to pathogens and control moisture loss. These lipids include wax esters and long chain fatty alcohols or policosanols. Cuticle fragments generated during several different fiber processing operations retain these lipid compou...

  14. Heterotrophic growth and lipid production of Chlorella protothecoides on glycerol.

    PubMed

    O'Grady, John; Morgan, John A

    2011-01-01

    During the production of biodiesel, a significant amount of glycerol is generated which currently has little commercial value. A study on the growth and lipid production of Chlorella protothecoides using glycerol as the carbon source was performed to demonstrate the utility of recycling crude glycerol created during biodiesel production. Glycerol was examined as both the sole carbon source and in combination with glucose. Algae cultures grown on only glycerol in shake flasks showed a specific growth rate and final lipid yield of 0.1/h and 0.31 g lipid/g substrate, respectively. The values were similar to those observed on pure glucose, 0.096/h and 0.24 g lipid/g substrate. When the media contained a mixture of glycerol and glucose, simultaneous uptake of the two substrates was observed. Due to the difference in rates of lipid storage, lipid production was 0.077 g lipid/(l h) during growth on glycerol, while growth on glucose had a productivity of 0.096 g lipid/(l h). During growth on the 9:1 mixture of both glucose and glycerol, lipid productivity was 0.098 g lipid/(l h). In order to simulate the use of waste glycerol from biodiesel production the experiments were repeated and similar growth rates, yields, and lipid productivities were achieved. Therefore, we have demonstrated the promise for simultaneous high growth rates and lipid yields of C. protothecoides heterotrophically grown on mixtures of glycerol. PMID:20976474

  15. Lipids and lipophilic components of Viburnum opulus fruits during maturation

    Microsoft Academic Search

    A. R. Karimova; S. G. Yunusova; E. G. Galkin; N. I. Fedorov; M. S. Yunusov

    2004-01-01

    The variation of the composition of neutral and polar lipids and lipophilic components during maturation of guelder rose (V. opulus L., fam. Caprifoliaceae) fruits was investigated. During fruit ripening, all lipid groups are accumulated, the highest accumulation rate being observed in the first period of maturation. In nonpolar lipids, this is due to a substantial increase in the content of

  16. 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)

  17. 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.

  18. Biomarkers of lipid peroxidation, airway inflammation and asthma

    Microsoft Academic Search

    L. G. Wood; P. G. Gibson; M. L. Garg

    2003-01-01

    Oxidative stress, specifically lipid peroxidation, is believed to contribute to the pathophysiology of asthma. This review highlights the pathways through which reactive oxygen species (ROS) may lead to lipid peroxidation. The potential of both the innate and acquired immune systems to activate inflammatory cells and release ROS that may overwhelm the host antioxidant defences and cause lipid peroxidation, accompanied by

  19. Rapid, colorimetric quantification of lipid from algal cultures

    Microsoft Academic Search

    Boris Wawrik; Brian H. Harriman

    2010-01-01

    Algae have significant potential as a source of biomass for the production of biofuels, due to their high growth rates and high cellular lipid content. Studies that address the use of algae as biofuels often require the frequent measurement of algal lipid content. Traditional methods for the quantification of lipid are, however, costly if sub-contracted, or involve the use of

  20. Elastic Constants of Polymer-Grafted Lipid Membranes

    Microsoft Academic Search

    Derek Marsh

    2001-01-01

    The surface expansion that is induced by the lateral pressure in the brush region of lipid membranes containing grafted polymers is deduced from the scaling and mean-field theories for the polymer brush, together with the equation of state for a lipid monolayer at the equivalence pressure with fluid lipid bilayers. Depending on the length and mole fraction of the polymer

  1. How protein transmembrane segments sense the lipid environment

    Microsoft Academic Search

    Thomas K. M. Nyholm; Suat Özdirekcan; J. Antoinette Killian

    2007-01-01

    Integral membrane proteins have central roles in a vast number of vital cellular processes. A structural feature that most membrane proteins have in common is the presence of one or more R-helices with which they traverse the lipid bilayer. Because of the interaction with the surrounding lipids, the organization of these transmembrane helices will be sensitive to lipid properties like

  2. 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…

  3. CASTOR SEED DEVELOPMENT AND STORAGE LIPID BIOSYNTHESIS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To identify additional enzymatic genes or regulatory genes that may up-regulate multiple activities or entire pathways leading to the ricinoleate and TAG syntheses in castor. we have analyzed expression profiles of twelve castor lipid genes. A series of castor seeds with well-defined developmental s...

  4. DNA damage caused by lipid peroxidation products.

    PubMed

    ?uczaj, Wojciech; Skrzydlewska, Elzbieta

    2003-01-01

    Lipid peroxidation is a process involving the oxidation of polyunsaturated fatty acids (PUFAs), which are basic components of biological membranes. Reactive electrophilic compounds are formed during lipid peroxidation, mainly alpha, beta-unsaturated aldehydes. These compounds yield a number of adducts with DNA. Among them, propeno and substituted propano adducts of deoxyguanosine with malondialdehyde (MDA), acrolein, crotonaldehyde and etheno adducts, resulting from the reactions of DNA bases with epoxy aldehydes, are a very important group of adducts. The epoxy aldehydes are more reactive towards DNA than the parent unsaturated aldehydes. The compounds resulting from lipid peroxidation mostly react with DNA showing both genotoxic and mutagenic action; among them, 4-hydroxynonenal is the most genotoxic, while MDA is the most mutagenic. DNA damage caused by the adducts of lipid peroxidation products with DNA can be removed by the repairing action of glycosylases. The formed adducts have been hitherto analyzed using the IPPA (Imunopurification-(32)P-postlabelling assay) method and via gas chromatography/electron capture negtive chemical ionization/mass spectrometry (GC/EC NCI/MS). A combination of liquid chromatography with electrospray tandem mass spectrometry (LC/ES-MSMS) with labelled inner standard has mainly been used in recent years. PMID:12813574

  5. Lipid Transfer Proteins and Allergy to Oranges

    Microsoft Academic Search

    Oussama Ahrazem; M. Dolores Ibáńez; Gema López-Torrejón; Rosa Sánchez-Monge; Joaquin Sastre; Manuel Lombardero; Domingo Barber; Gabriel Salcedo

    2005-01-01

    Background: Lipid transfer proteins (LTPs) are relevant fruit allergens, recently proposed as model plant food allergens. No citrus fruit allergen has been characterized to date. We sought to identify and isolate citrus fruit LTPs and to explore their relevance in orange allergy. Methods: Twenty-seven patients, showing mainly oral allergy syndrome after orange ingestion, as well as positive prick responses and

  6. 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.

  7. Characterization of the Drosophila Lipid Droplet Subproteome

    Microsoft Academic Search

    Mathias Beller; Dietmar Riedel; Lothar Jansch; Guido Dieterich; Herbert Jackle; Ronald P. Kuhnlein

    2006-01-01

    Lipid storage droplets are universal organelles essential for the cellular and organismal lipometabolism including en- ergy homeostasis. Despite their apparently simple design they are proposed to participate in a growing number of cellular processes, raising the question to what extent the functional multifariousness is reflected by a complex or- ganellar proteome composition. Here we present 248 pro- teins identified in

  8. Serum lipids and cardiovascular reactivity to stress

    Microsoft Academic Search

    Lorenz J. P. van Doornen; Harold Snieder; Dorret I. Boomsma

    1998-01-01

    Several studies have reported an association between serum lipid levels and cardiovascular reactivity to laboratory stressors. Their findings, however, are equivocal. The inconsistencies may be due to shortcomings such as the small number of subjects, the inclusion of patient groups, no control for medication, and no control for age effects. Two studies are presented investigating the relationship in large groups

  9. Glycerol prevents dehydration in lipid cubic phases.

    PubMed

    Richardson, S J; Staniec, P A; Newby, G E; Rawle, J L; Slaughter, A R; Terrill, N J; Elliott, J M; Squires, A M

    2015-07-01

    Lipid cubic phase samples dry out and undergo phase transitions when exposed to air. We demonstrate experimentally and theoretically that adding glycerol controllably lowers the humidity at which cubic phases form. These results broaden the potential applications of cubic phases and open up the potential of a new humidity-responsive nanomaterial. PMID:26084976

  10. 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...

  11. Lipidomics: coming to grips with lipid diversity

    Microsoft Academic Search

    Andrej Shevchenko; Kai Simons

    2010-01-01

    Although lipids are biomolecules with seemingly simple chemical structures, the molecular composition of the cellular lipidome is complex and, currently, poorly understood. The exact mechanisms of how compositional complexity affects cell homeostasis and its regulation also remain unclear. This emerging field is developing sensitive mass spectrometry technologies for the quantitative characterization of the lipidome. Here, we argue that lipidomics will

  12. 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...

  13. 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

  14. Respiratory Allergy to Lipid Transfer Protein

    Microsoft Academic Search

    Franco Borghesan; Gianni Mistrello; Daniela Roncarolo; Stefano Amato; Mario Plebani; Riccardo Asero

    2008-01-01

    Background: Due to unclear reasons, allergy to lipid transfer protein (LTP) is frequent in Mediterranean countries but rare in Northern Europe. Objective: We report a paradigmatic case of primarily airborne sensitization to LTP that might explain the geographical distribution of this type of food allergy. Methods: A 21-year-old woman began having severe perennial rhinitis 6 months after she started working

  15. Engineering lipid bilayer membranes for protein studies.

    PubMed

    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

  16. Physiology and pathophysiology of liver lipid metabolism.

    PubMed

    Ponziani, Francesca Romana; Pecere, Silvia; Gasbarrini, Antonio; Ojetti, Veronica

    2015-08-01

    Liver lipid metabolism and its modulation are involved in many pathologic conditions, such as obesity, non-alcoholic fatty liver disease, diabetes mellitus, atherosclerosis and cardiovascular disease. Metabolic disorders seem to share a similar background of low-grade chronic inflammation, even if the pathophysiological mechanisms leading to tissue and organ damage have not been completely clarified yet. The accumulation of neutral lipids in the liver is now recognized as a beneficial and protective mechanism; on the other hand, lipoperoxidation is involved in the development and progression of non-alcoholic steatohepatitis. The role of the gut microbiota in liver lipid metabolism has been the object of recent scientific investigations. It is likely that the gut microbiota is involved in a complex metabolic modulation and the translocation of gut microflora may also contribute to maintaining the low-grade inflammatory status of metabolic syndrome. Therefore, lipid metabolism pathology has vague limits and complex mechanisms, and the knowledge of these is essential to guide diagnostic and therapeutic decisions. PMID:26070860

  17. Imaging lipid droplets by electron microscopy.

    PubMed

    Fujimoto, Toyoshi; Ohsaki, Yuki; Suzuki, Michitaka; Cheng, Jinglei

    2013-01-01

    The lipid droplet (LD) is different from other cellular organelles in that most of its volume is made of lipid esters and its surface is lined by a phospholipid monolayer. This uniquely lipid-dominant structure poses a problem for electron microscopy (EM) because the aldehydes commonly used as a fixative do not react with most lipids. To circumvent this difficulty and utilize the high resolving power of EM, many methods have been developed. In this chapter, we discuss methods that have been used and/or are potentially useful to study LDs. The methods include conventional EM to observe the LD core, cryoelectron microscopy to observe the LD surface, freeze-substitution, immunoelectron microscopy (pre-embedding, post-embedding, and cryosectioning methods), and freeze-fracture. Each method has strong and weak points and therefore some caution is necessary in interpreting the obtained results. In combination with methods of other disciplines, the electron microscopic techniques should contribute significantly to solving the remaining questions on LDs. PMID:24099296

  18. LIPID BIOMARKER ANALYSIS OF MARINE DINOFLAGELLATES

    EPA Science Inventory

    Many marine eukaryotic algae have been shown to possess characteristic chemotaxonomic lipid biomarkers. Dinoflagellates in particular are often characterized by the presence of sterols and pigments that are rarely found in other classes of algae. To evaluate the utility of chemic...

  19. 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):...

  20. Resolving lipids: lipoxins regulate reverse cholesterol transport.

    PubMed

    Spite, Matthew

    2014-12-01

    Disruptions in cholesterol homeostasis contribute to cardiovascular disease (CVD). In a recent issue of Cell Metabolism, Demetz et al. (2014) report that endogenous lipoxygenase-mediated metabolism of another lipid, arachidonic acid, produces lipoxins that regulate reverse cholesterol transport. These results suggest that lipoxins may represent a novel class of therapeutics for CVD. PMID:25470544

  1. Effect of Tamoxifen on Serum Lipid Metabolism

    Microsoft Academic Search

    YASUO HOZUMI; MIKIHIKO KAWANO; TSUYOSHI SAITO; MICHIO MIYATA

    The effect of tamoxifen, an antiestrogenic agent, on lipid metab- olism was studied in postmenopausal patients with breast cancer who received the drug for postoperative adjuvant treatment following mastectomy. To measure total cholesterol and triglyceride concen- trations, fasting blood samples were collected before and 2 months after the initiation of tamoxifen therapy from 16 patients who sat- isfied the study

  2. Molecular dynamics simulations of lipid bilayers

    Microsoft Academic Search

    Scott E. Feller

    2000-01-01

    Computer simulation methods are becoming increasingly widespread as tools for studying the structure and dynamics of lipid bilayer membranes. The length scale and time scale accessible to atomic-level molecular dynamics simulations are rapidly increasing, providing insight into the relatively slow motions of molecular reorientation and translation and demonstrating that effects due to the finite size of the simulation cell can

  3. 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...

  4. Stability of lipid encapsulated ferulic acid particles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Encapsulation of bioactive compounds by a solid lipid matrix provides stability and a mechanism for controlled release in formulated products. Phenolic compounds exhibit antioxidant and antimicrobial activities and have applications as functional food and feed additives. Ferulic acid, a common pheno...

  5. Lysosomal exocytosis and lipid storage disorders

    PubMed Central

    Samie, Mohammad Ali; Xu, Haoxing

    2014-01-01

    Lysosomes are acidic compartments in mammalian cells that are primarily responsible for the breakdown of endocytic and autophagic substrates such as membranes, proteins, and lipids into their basic building blocks. Lysosomal storage diseases (LSDs) are a group of metabolic disorders caused by genetic mutations in lysosomal hydrolases required for catabolic degradation, mutations in lysosomal membrane proteins important for catabolite export or membrane trafficking, or mutations in nonlysosomal proteins indirectly affecting these lysosomal functions. A hallmark feature of LSDs is the primary and secondary excessive accumulation of undigested lipids in the lysosome, which causes lysosomal dysfunction and cell death, and subsequently pathological symptoms in various tissues and organs. There are more than 60 types of LSDs, but an effective therapeutic strategy is still lacking for most of them. Several recent in vitro and in vivo studies suggest that induction of lysosomal exocytosis could effectively reduce the accumulation of the storage materials. Meanwhile, the molecular machinery and regulatory mechanisms for lysosomal exocytosis are beginning to be revealed. In this paper, we first discuss these recent developments with the focus on the functional interactions between lipid storage and lysosomal exocytosis. We then discuss whether lysosomal exocytosis can be manipulated to correct lysosomal and cellular dysfunction caused by excessive lipid storage, providing a potentially general therapeutic approach for LSDs. PMID:24668941

  6. Lipid nanoparticles for dermal drug delivery.

    PubMed

    Kakadia, Pratibha G; Conway, Barbara R

    2015-01-01

    Lipid based drug delivery systems have been widely studied and reported over the past decade and offer a useful alternative to other colloidal drug delivery systems. Skin is a popular route of drug delivery for locally and systemically acting drugs and nanoparticles are reported as a potential formulation strategy for dermal delivery. Although the skin acts as a natural physical barrier against penetration of foreign materials, including particulates, opportunities exist for the delivery of therapeutic nanoparticles, especially in diseased and damaged skin and via appendageal routes such as the openings of hair follicles. The extent and ability of nanoparticles to penetrate into the underlying viable tissue is still the subject of debate although recent studies have identified the follicular route as the most likely route of entry; this influences the potential applications of these dosage forms as a drug delivery strategy. This paper reviews present state of art of lipid-based nanocarriers focussing on solid lipid nanoparticles, nanostructured lipid carriers and nanoemulsions, their production methods, potential advantages and applications in dermal drug delivery. PMID:25925115

  7. Lipid droplet targeting domains of adipophilin

    Microsoft Academic Search

    James L. McManaman; William Zabaronick; Jerome Schaack; David J. Orlicky

    2003-01-01

    Adipophilin (ADPH), a prominent protein com- ponent of lipid storage droplets (LSDs), is postulated to be necessary for the formation and cellular function of these structures. The presence of significant sequence similarities within an ? 100 amino acid region of the N-terminal por- tions of ADPH and related LSD binding proteins, perilipin and TIP47, has implicated this region, known as

  8. Electrochemical Study of the Bilayer Lipid Membrane

    Microsoft Academic Search

    Erkang Wang; Xiaojun Han

    2005-01-01

    We summarized the recent work of our group with electrochemistry as the main study method. This chapter was divided into seven sections.1. The ion-channel behavior of gramicidin in bilayer lipid membrane (BLM). Gramicidin was incorporated in a BLM. The behavior of the ion channel was studied by cyclic voltammetry. At a very low concentration of gramicidin in a BLM, the

  9. 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...

  10. 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

  11. Lipid mono- and bilayer supported on polymer films: composite polymer-lipid films on solid substrates.

    PubMed Central

    Kühner, M; Tampé, R; Sackmann, E

    1994-01-01

    We report the deposition of lipid monolayers and bilayers on polyacrylamide films deposited by radical chain reaction onto solid substrates in aqueous solutions. Polymer films of various degrees of monomer density and cross-linking are prepared. Lateral diffusion and fluorescent probe permeation measurements yield insight into the continuity of the lipid layers and show that monolayers exposed to air are much less sensitive towards polymer heterogeneities than bilayers below water, which is explained in terms of the wetting laws. The diffusion studies of lipid and lipopeptide probes yield absolute values of the frictional coefficients between the lipid layer and the polymer films and allow one to estimate the surface viscosity of the polymer film. The potential applications of supported membranes on soft thin polymer films for the preparation of biofunctionalized surfaces or biocompatible receptive surfaces for biosensors are discussed. Images FIGURE 2 FIGURE 3 FIGURE 4 PMID:7918990

  12. LipidBlast - in-silico tandem mass spectrometry database for lipid identification

    PubMed Central

    Kind, Tobias; Liu, Kwang-Hyeon; Yup Lee, Do; DeFelice, Brian; Meissen, John K.; Fiehn, Oliver

    2013-01-01

    Current tandem mass spectral libraries for lipid annotations in metabolomics are limited in size and diversity. We provide a freely available computer generated in-silico tandem mass spectral library of 212,516 MS/MS spectra covering 119,200 compounds from 26 lipid compound classes, including phospholipids, glycerolipids, bacterial lipoglycans and plant glycolipids. Platform independence is shown by using tandem mass spectra from 40 different mass spectrometer types including low-resolution and high-resolution instruments. PMID:23817071

  13. Effect of beeswax modification on the lipid matrix and solid lipid nanoparticle crystallinity

    Microsoft Academic Search

    Anthony A. Attama; Christel C. Müller-Goymann

    2008-01-01

    The influence of a heterolipid (Phospholipon 90G®, P90G), which directly modifies the surface of solid lipid nanoparticles (SLN), and goat fat on the crystallinity of beeswax matrix and the SLN prepared therefrom was studied. Lipid matrices composed of 30% (w\\/w) of P90G in beeswax and in 1:1 mixture of beeswax and goat fat were formulated and characterized. SLN containing polysorbate

  14. Regulation of Calcium Channel Activity by Lipid Domain Formation in Planar Lipid Bilayers

    PubMed Central

    Cannon, Brian; Hermansson, Martin; Györke, Sandor; Somerharju, Pentti; Virtanen, Jorma A.; Cheng, Kwan Hon

    2003-01-01

    The sarcoplasmic reticulum channel (ryanodine receptor) from cardiac myocytes was reconstituted into planar lipid bilayers consisting of 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE) and 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) in varying ratios. The channel activity parameters, i.e., open probability and average open time and its resolved short and long components, were determined as a function of POPE mole fraction (XPE) at 22.4°C. Interestingly, all of these parameters exhibited a narrow and pronounced peak at XPE ? 0.80. Differential scanning calorimetric measurements on POPE/POPC liposomes with increasing XPE indicated that the lipid bilayer enters a composition-driven transition from the liquid-crystalline state to the gel state at 22.4°C when XPE approaches 0.80. Thus, the peaking of the reconstituted channel activity at XPE ? 0.80 in the planar bilayer could result from the appearance of gel/liquid-crystalline domain boundaries at this POPE content. Lipid packing at domain boundaries is known to be looser as compared to the homogenous gel or liquid-crystalline state. We propose that the attractive potential of packing defects at lipid domain boundaries and entropic excluded-volume effects could result in the direct interactions of the transmembrane region of the channel protein with the lipid-packing defects at the lipid/protein interface, which could thus provide a favorable environment for the open state of the protein. The present findings indicate that the activity of the sarcoplasmic reticulum calcium channel could be modulated by lipid domain formation upon slight changes in membrane lipid composition in vivo. PMID:12885640

  15. Cuticular lipids of insects as potential biofungicides: methods of lipid composition analysis.

    PubMed

    Go??biowski, Marek; Bogu?, Mieczys?awa I; Paszkiewicz, Monika; Stepnowski, Piotr

    2011-03-01

    The main function of cuticular lipids in insects is the restriction of water transpiration through the surface. Lipids are involved in various types of chemical communication between species and reduce the penetration of insecticides, chemicals, and toxins and they also provide protection from attack by microorganisms, parasitic insects, and predators. Hydrocarbons, which include straight-chain saturated, unsaturated, and methyl-branched hydrocarbons, predominate in the cuticular lipids of most insect species; fatty acids, alcohols, esters, ketones, aldehydes, as well as trace amounts of epoxides, ethers, oxoaldehydes, diols, and triacylglycerols have also been identified. Analyses of cuticular lipids are chemically relatively straightforward, and methods for their extraction should be simple. Classically, extraction has relied mainly on application of apolar solvents to the entire insect body. Recently, several alternative methods have been employed to overcome some of the shortcomings of solvent extraction. These include the use of solid-phase microextraction (SPME) fibers to extract hydrocarbons from the headspace of heated samples, SPME to sample live individuals, and a less expensive method (utilized for social wasps), which consists of the collection of cuticular lipids by means of small pieces of cotton rubbed on the body of the insect. Both classical and recently developed extraction methods are reviewed in this work. The separation and analysis of the insect cuticular lipids were performed by column chromatography, thin-layer chromatography (TLC), high performance liquid chromatography with a laser light scattering detector (HPLC-LLSD), gas chromatography (GC), and GC-mass spectrometry (MS). The strategy of lipid analysis with the use of chromatographic techniques was as follows: extraction of analytes from biological material, lipid class separation by TLC, column chromatography, HPLC-LLSD, derivatization, and final determination by GC, GC-MS, matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) MS, and liquid chromatography-mass spectrometry (LC-MS). PMID:21153591

  16. 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 Ĺ 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-Ĺ-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

  17. Cellular transport and lipid interactions of miltefosine.

    PubMed

    Barratt, Gillian; Saint-Pierre-Chazalet, Mich?le; Loiseau, Philippe Marie

    2009-03-01

    Miltefosine (hexadecylphosphocholine, HePC) is an alkyl phospholipid which was first developed as an anticancer agent for local treatment of skin metastases. It was later found to have remarkable activity against Leishmania parasites by the oral route and is marketed as Impavido(R) for this indication. The mechanism of action of HePC involves interaction with lipids and in particular membrane lipids - phospholipids and sterols. Studies of interactions between HePC and these lipids carried out in model systems suggest an affinity of HePC for cholesterol-rich lipid rafts. The uptake of HePC by cancer cells begins by insertion into the plasma membrane which may be followed by internalization. Within the plasma membrane, HePC interferes with the functioning of a number of enzymes involved in phospholipid metabolism, including protein kinase C and the phospholipases A(2), C and D, and can also induce apoptosis. Effects on lipid metabolism have also been observed in Leishmania parasites. In these organisms, a proposed mechanism of HePC uptake can be proposed: HePC inserts into the outer leaflet of the plasma membrane as monomers when its concentration is below the critical micellar concentration (CMC) and as both monomers and oligomers when it is above the CMC. Thereafter, a two-subunit aminophospholipid translocase, LdMT-LdRos3, internalizes the drug. Some evidence obtained in the Caco-2 intestinal cell model suggests that a similar process may occur during the oral absorption of HePC. Finally, the use of phospholipid vesicles (liposomes) as carrier systems for HePC, reducing its toxic side-effects, is reviewed. PMID:19442087

  18. Mixtures of Cationic Lipid O-Ethylphosphatidylcholine with Membrane Lipids and DNA: Phase Diagrams

    PubMed Central

    Koynova, Rumiana; MacDonald, Robert C.

    2003-01-01

    Ethylphosphatidylcholines are positively charged membrane lipid derivatives, which effectively transfect DNA into cells and are metabolized by the cells. For this reason, they are promising nonviral transfection agents. With the aim of revealing the kinds of lipid phases that may arise when lipoplexes interact with cellular lipids during DNA transfection, temperature-composition phase diagrams of mixtures of the O-ethyldipalmitoylphosphatidylcholine with representatives of the major lipid classes (phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, cholesterol) were constructed. Phase boundaries were determined using differential scanning calorimetry and synchrotron x-ray diffraction. The effects of ionic strength and of DNA presence were examined. A large variety of polymorphic and mesomorphic structures were observed. Surprisingly, marked enhancement of the affinity for nonlamellar phases was observed in mixtures with phosphatidylethanolamine and cholesterol as well as with phosphatidylglycerol (previously reported). Because of the potential relevance to transfection, it is noteworthy that such phases form at close to physiological conditions, and in the presence of DNA. All four mixtures exhibit a tendency to molecular clustering in the gel phase, presumably due to the specific interdigitated molecular arrangement of the O-ethyldipalmitoylphosphatidylcholine gel bilayers. It is evident that a remarkably broad array of lipid phases could arise in transfected cells and that these could have significant effects on transfection efficiency. The data may be particularly useful for selecting possible “helper” lipids in the lipoplex formulations, and in searches for correlations between lipoplex structure and transfection activity. PMID:14507708

  19. Physical properties of the lipid bilayer membrane made of calf lens lipids: EPR spin labeling studies

    PubMed Central

    Widomska, Justyna; Raguz, Marija; Dillon, James; Gaillard, Elizabeth R.; Subczynski, Witold K.

    2007-01-01

    The physical properties of a membrane derived from the total lipids of a calf lens were investigated using EPR spin labeling and were compared with the properties of membranes made of an equimolar 1-palmitoyl-2-oleoylphosphatidylcholine/cholesterol (POPC/Chol) mixture and of pure POPC. Conventional EPR spectra and saturation-recovery curves show that spin labels detect a single homogenous environment in all three membranes. Profiles of the order parameter, hydrophobicity, and oxygen transport parameter are practically identical in lens lipid and POPC/Chol membranes, but differ drastically from profiles in pure POPC membranes. In both lens lipid and POPC/Chol membranes, the lipids are strongly immobilized at all depths, which is in contrast to the high fluidity of the POPC membrane. Hydrophobicity and oxygen transport parameter profiles in lens lipid and POPC/Chol membranes have a rectangular shape with an abrupt change between the C9 and C10 positions, which is approximately where the steroid ring structure of cholesterol reaches into the membrane. At this position, hydrophobicity increases from the level of methanol to the level of hexane, and the oxygen transport parameter increases by a factor of 2-3. These profiles in POPC membranes are bell-shaped. It is concluded that the high level of cholesterol in lens lipids makes the membrane stable, immobile, and impermeable to both polar and nonpolar molecules. PMID:17451639

  20. Oxidized lipids in the diet are a source of oxidized lipid in chylomicrons of human serum.

    PubMed

    Staprăns, I; Rapp, J H; Pan, X M; Kim, K Y; Feingold, K R

    1994-12-01

    We examined whether oxidized lipids in the diet determine the levels of oxidized lipid in human postprandial serum chylomicrons. After we fed subjects control corn oil containing low quantities of oxidized lipid, the levels of conjugated dienes in the chylomicron fraction were low (9.67 +/- 0.92 nmol/mumol triglyceride), and no thiobarbituric acid-reactive substances (TBARS) could be detected. However, when subjects were fed a highly oxidized oil, the conjugated diene content in chylomicrons was increased 4.7-fold to 46 +/- 5.63 nmol/mumol triglyceride, with 0.140 +/- 0.03 nmol TBARS/mumol triglyceride. When subjects were fed medium-oxidized oil, the degree of oxidation of the chylomicron lipids was moderately increased (21.86 +/- 2.03 nmol conjugated dienes/mumol triglyceride). Additionally, we found that chylomicrons isolated after ingestion of oxidized oil were more susceptible to CuSO4 oxidation than chylomicrons isolated after ingestion of the control oil. The lag time for oxidation decreased from 4.30 +/- 0.40 to 3.24 +/- 0.51 hours (P < .05). These data demonstrate that in humans dietary oxidized lipids are absorbed by the small intestine, incorporated into chylomicrons, and appear in the bloodstream, where they contribute to the total body pool of oxidized lipid. PMID:7981177

  1. 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

  2. Lipid-lipid interactions in aminated reduced graphene oxide interface for biosensing application.

    PubMed

    Ali, Md Azahar; Kamil Reza, K; Srivastava, Saurabh; Agrawal, Ved Varun; John, Renu; Malhotra, Bansi Dhar

    2014-04-15

    A label-free biosensor based on antiapolipoprotein B 100 functionalized-aminated reduced graphene oxide interface has been fabricated for detection of low density lipoprotein (LDL or lipid) cholesterol. The aminated reduced graphene oxide (NH2-rGO) based electrode surface is covalently functionalized with antiapolipoprotein B 100 (AAB or lipid) using EDC/NHS coupling chemistry. The lipid-lipid interactions at the NH2-rGO electrode surface have been investigated using electrochemical impedance spectroscopic technique. The structural and morphological investigations of NH2-rGO based immunosensor have been accomplished via transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, UV-visible, and electrochemical techniques. The impedimetric response of the proposed immunosensor shows excellent sensitivity (612 ? mg(-1) dL cm(-2)), a response time of 250 s, and a low detection limit of 5 mg/dL of LDL molecules. The association, dissociation, and equilibrium rate constants for this immunoelectrode are found to be 1.66 M(-1) s(-1), 0.6 s(-1), and 2.77 M(-1), respectively. The long-term stability and excellent reproducibility of the proposed immunosensor indicates a suitable platform for detection of LDL or lipid molecules. This immunosensor provides an efficient platform for analysis of the antigen-antibody interactions of lipid molecules. PMID:24673363

  3. Lipid domains control myelin basic protein adsorption and membrane interactions between model myelin lipid bilayers

    PubMed Central

    Lee, Dong Woog; Banquy, Xavier; Kristiansen, Kai; Kaufman, Yair; Boggs, Joan M.; Israelachvili, Jacob N.

    2014-01-01

    The surface forces apparatus and atomic force microscope were used to study the effects of lipid composition and concentrations of myelin basic protein (MBP) on the structure of model lipid bilayers, as well as the interaction forces and adhesion between them. The lipid bilayers had a lipid composition characteristic of the cytoplasmic leaflets of myelin from “normal” (healthy) and “disease-like” [experimental allergic encephalomyelitis (EAE)] animals. They showed significant differences in the adsorption mechanism of MBP. MBP adsorbs on normal bilayers to form a compact film (3–4 nm) with strong intermembrane adhesion (?0.36 mJ/m2), in contrast to its formation of thicker (7–8 nm) swelled films with weaker intermembrane adhesion (?0.13 mJ/m2) on EAE bilayers. MBP preferentially adsorbs to liquid-disordered submicron domains within the lipid membranes, attributed to hydrophobic attractions. These results show a direct connection between the lipid composition of membranes and membrane–protein adsorption mechanisms that affects intermembrane spacing and adhesion and has direct implications for demyelinating diseases. PMID:24516125

  4. Characterization of the lateral distribution of fluorescent lipid in binary-constituent lipid monolayers by principal component analysis.

    PubMed

    Sugár, István P; Zhai, Xiuhong; Boldyrev, Ivan A; Molotkovsky, Julian G; Brockman, Howard L; Brown, Rhoderick E

    2010-01-01

    Lipid lateral organization in binary-constituent monolayers consisting of fluorescent and nonfluorescent lipids has been investigated by acquiring multiple emission spectra during measurement of each force-area isotherm. The emission spectra reflect BODIPY-labeled lipid surface concentration and lateral mixing with different nonfluorescent lipid species. Using principal component analysis (PCA) each spectrum could be approximated as the linear combination of only two principal vectors. One point on a plane could be associated with each spectrum, where the coordinates of the point are the coefficients of the linear combination. Points belonging to the same lipid constituents and experimental conditions form a curve on the plane, where each point belongs to a different mole fraction. The location and shape of the curve reflects the lateral organization of the fluorescent lipid mixed with a specific nonfluorescent lipid. The method provides massive data compression that preserves and emphasizes key information pertaining to lipid distribution in different lipid monolayer phases. Collectively, the capacity of PCA for handling large spectral data sets, the nanoscale resolution afforded by the fluorescence signal, and the inherent versatility of monolayers for characterization of lipid lateral interactions enable significantly enhanced resolution of lipid lateral organizational changes induced by different lipid compositions. PMID:20414462

  5. Functional lipids and lipoplexes for improved gene delivery

    PubMed Central

    Zhang, Xiao-Xiang; McIntosh, Thomas J.; Grinstaff, Mark W.

    2013-01-01

    Cationic lipids are the most common non-viral vectors used in gene delivery with a few currently being investigated in clinical trials. However, like most other synthetic vectors, these vectors suffer from low transfection efficiencies. Among the various approaches to address this challenge, functional lipids (i.e., lipids responding to a stimuli) offer a myriad of opportunities for basic studies of nucleic acid–lipid interactions and for in vitro and in vivo delivery of nucleic acid for a specific biological/medical application. This manuscript reviews recent advances in pH, redox, and charge-reversal sensitive lipids. PMID:21621581

  6. Solid lipid nanodispersions containing mixed lipid core and a polar heterolipid: characterization.

    PubMed

    Attama, A A; Schicke, B C; Paepenmüller, T; Müller-Goymann, C C

    2007-08-01

    This paper describes the characterization of solid lipid nanodispersions (SLN) prepared with a 1:1 mixture of theobroma oil and goat fat as the main lipid matrix and Phospholipon 90G (P90G) as a stabilizer heterolipid, using polysorbate 80 as the mobile surfactant, with a view to applying the SLN in drug delivery. The 1:1 lipid mixture and P90G constituting the lipid matrix was first homogeneously prepared by fusion. Thereafter, the SLN were formulated with a gradient of polysorbate 80 and constant lipid matrix concentration by melt-high pressure homogenisation. The SLN were characterized by time-resolved particle size analysis, zeta potential and osmotic pressure measurements, differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). Transmission electron microscopy (TEM) and isothermal heat conduction microcalorimetry (IMC) which monitors the in situ crystallization were also carried out on the SLN containing P90G and 1.0 % w/w of polysorbate 80. The results obtained in these studies were compared with SLN prepared with theobroma oil with and without phospholipid. Particle size analysis of SLN indicated reduction in size with increase in concentration of mobile surfactant and was in the lower nanometer range after 3 months except SLN prepared without P90G or polysorbate 80. The lipid nanoparticles had negative potentials after 3 months. WAXD and DSC studies revealed low crystalline SLN after 3 months of storage except in WAXD of SLN formulated with 1.0 % w/w polysorbate 80. TEM micrograph of the SLN containing 1.0 % w/w polysorbate 80 revealed discrete particles whose sizes were in consonance with the static light scattering measurement. In situ crystallization studies in IMC revealed delayed crystallization of the SLN with 1.0 % w/w polysorbate 80. Results indicate lipid mixtures produced SLN with lower crystallinity and higher particle sizes compared with SLN prepared with theobroma oil alone with or without P90G, and would lead to higher drug incorporation efficiency when used in formulation of actives. Mixtures of theobroma oil and goat fat would be suitable for the preparation of nanostructured lipid carriers. SLN of theobroma oil containing phospholipid could prove to be a good ocular or parenteral drug delivery system considering the low particle size, particle size stability and in vivo tolerability of the component lipids. SLN prepared with lipid admixture, which had higher increase in d(90%) on storage are suitable for preparation of topical and transdermal products. PMID:17276663

  7. Screening of Lipid Carriers and Characterization of Drug-Polymer-Lipid Interactions for the Rational Design of Polymer-Lipid Hybrid Nanoparticles (PLN)

    Microsoft Academic Search

    Yongqiang Li; Nicolas Taulier; Andrew M. Rauth; Xiao Yu Wu

    2006-01-01

    Purpose  The thermodynamics and solid state properties of components and their interactions in a formulation for polymer-lipid hybrid nanoparticles (PLN) were characterized for screening lead lipid carriers and rational design of PLN.Methods  Verapamil HCl (VRP) was chosen as a model drug and dextran sulfate sodium (DS) as a counter-ionic polymer. Solubility parameters of VRP, VRP-DS complex, and various lipids were calculated and

  8. Angiomatosis retinae. An ultrastructural study and lipid analysis.

    PubMed

    Jakobiec, F A; Font, R L; Johnson, F B

    1976-11-01

    A nonfamilial case of agiomatosis retinae (retinal hemangioblastoma) was studied by electron microscopy. In addition to the three major types of cells previously identified within the tumor (endothelial cells, pericytes, heavily lipidized stromal cells), fibrous astrocytes in different stages of lipidization were also found. The endothelial cells were fenestrated, providing the basis for the extravasated exudate that is characteristic of the tumor. The pericytes were completely surrounded by casement membranes and displayed no significant lipidization; in a cellular plaque of vasular tissue at the base of the lesion, however, some of the multilaminar pericytes showed evidence of early smooth muscle differentiation. The stromal cells contained abundant lipid vacuoles and a few organelles, and exhibited granular degeneration of cytoplasmic filaments between the lipid vacuoles. There was spotty basement membrane formation where the stromal cells abutted on the vascular elements. No interconversion could be demonstrated among the endothelial cells, pericytes, and stromal cells. A source for the stromal cells was discovered in the early lipisization of fibrous astrocytes. Analysis of the extracted lipid from the tumor by means of infrared spectroscopy, lipid chromatography, and x-ray diffraction disclosed that the lipid was mostly cholestrol stearate, a plasma lipid. It is suggested that in the retinal lesions the leaky (fenestrated) capillaries of the tumor allowed the passive imbibition of plasma lipid by the fibrous astrocytes, leading to their gradual transformation into the fully lipidized stromal cells. PMID:1033029

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

    SciTech Connect

    George, Kimberly S. [Edison Biotechnology Institute and Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701 (United States) [Edison Biotechnology Institute and Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701 (United States); Department of Chemistry, Marietta College, Marietta, OH 45750 (United States); Wu, Shiyong, E-mail: wus1@ohio.edu [Edison Biotechnology Institute and Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701 (United States)] [Edison Biotechnology Institute and Department of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701 (United States)

    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.

  10. Control of lipid metabolism by Tachykinin in Drosophila

    PubMed Central

    Song, Wei; Veenstra, Jan A.; Perrimon, Norbert

    2015-01-01

    Summary The intestine is a key organ for lipid uptake and distribution, and abnormal intestinal lipid metabolism is associated with obesity and hyperlipidemia. Although multiple regulatory gut hormones secreted from enteroendocrine cells (EEs) regulate systemic lipid homeostasis, such as appetite control and energy balance in adipose tissue, their respective roles regarding lipid metabolism in the intestine are not well understood. We demonstrate that Tachykinins (TKs), one of the most abundant secreted peptides expressed in midgut EEs, regulate intestinal lipid production and subsequently control systemic lipid homeostasis in Drosophila, and that TKs repress lipogenesis in enterocytes (ECs) associated with the TKR99D receptor and PKA signaling. Interestingly, nutrient deprivation enhances the production of TKs in the midgut. Finally, unlike the physiological roles of TKs produced from the brain, gut-derived TKs do not affect behavior, thus demonstrating that gut TK hormones specifically regulate intestinal lipid metabolism without affecting neuronal functions. PMID:25263556

  11. Deformation and stability of lipid membranes in electric fields

    NASA Astrophysics Data System (ADS)

    Vlahovska, Petia

    2010-11-01

    The challenges and recent advances in the theoretical modeling of lipid membrane dynamics in electric fields will be overviewed. Vesicle shapes and the stability and poration of lipid bilayers will be discussed in relation to the complex electromechanics of membranes: First, the lipid membrane is an insulating shell impermeable to ions. Second, it is essentially a two-dimensional incompressible-fluid sheet; under stress lipid membranes store elastic energy in bending, while membranes made of cross-linked polymers are more likely to be stretched and sheared. Third, lipid membranes are extremely soft and they are easily bent by the thermal noise. I will show how the dynamical coupling of interface charging, membrane deformation, lipid density redistribution, and fluid motion gives rise to rich and sometimes surprising behavior of lipid membranes in electric fields.

  12. The simulation approach to lipid-protein interactions.

    PubMed

    Paramo, Teresa; Garzón, Diana; Holdbrook, Daniel A; Khalid, Syma; Bond, Peter J

    2013-01-01

    The interactions between lipids and proteins are crucial for a range of biological processes, from the folding and stability of membrane proteins to signaling and metabolism facilitated by lipid-binding proteins. However, high-resolution structural details concerning functional lipid/protein interactions are scarce due to barriers in both experimental isolation of native lipid-bound complexes and subsequent biophysical characterization. The molecular dynamics (MD) simulation approach provides a means to complement available structural data, yielding dynamic, structural, and thermodynamic data for a protein embedded within a physiologically realistic, modelled lipid environment. In this chapter, we provide a guide to current methods for setting up and running simulations of membrane proteins and soluble, lipid-binding proteins, using standard atomistically detailed representations, as well as simplified, coarse-grained models. In addition, we outline recent studies that illustrate the power of the simulation approach in the context of biologically relevant lipid/protein interactions. PMID:23404287

  13. New fluorescent octadecapentaenoic acids as probes of lipid membranes and protein-lipid interactions.

    PubMed

    Mateo, C R; Souto, A A; Amat-Guerri, F; Acuńa, A U

    1996-10-01

    The chemical and spectroscopic properties of the new fluorescent acids all(E)-8, 10, 12, 14, 16-octadecapentaenoic acid (t-COPA) and its (8Z)-isomer (c-COPA) have been characterized in solvents of different polarity, synthetic lipid bilayers, and lipid/protein systems. These compounds are reasonably photostable in solution, present an intense UV absorption band (epsilon(350 nm) approximately 10(5) M(-1) cm(-1)) strongly overlapped by tryptophan fluorescence and their emission, centered at 470 nm, is strongly polarized (r(O) = 0.385 +/- 0.005) and decays with a major component (85%) of lifetime 23 ns and a faster minor one of lifetime 2 ns (D,L-alpha-dimyristoylphosphatidylcholine (DMPC), 15 degrees C). Both COPA isomers incorporate readily into vesicles and membranes (K(p) approximately 10(6)) and align parallel to the lipids. t-COPA distributes homogeneously between gel and fluid lipid domains and the changes in polarization accurately reflect the lipid T(m) values. From the decay of the fluorescence anisotropy in spherical bilayers of DMPC and POPC it is shown that t-COPA also correctly reflects the lipid order parameters, determined by 2H NMR techniques. Resonance energy transfer from tryptophan to the bound pentaenoic acid in serum albumin in solution, and from the tryptophan residues of gramicidin in lipid bilayers also containing the pentaenoic acid, show that this probe is a useful acceptor of protein tryptophan excitation, with R(O) values of 30-34 A. PMID:8889194

  14. Low levels of lipid oxidation radically increase the passive permeability of lipid bilayers.

    PubMed

    Runas, Kristina A; Malmstadt, Noah

    2015-01-21

    Oxidation of unsaturated lipids in cellular membranes has been shown to cause severe membrane damage and potentially cell death. The presence of oxidized lipid species in the membrane is known to cause changes in membrane properties, such as decreased fluidity. This study uses giant unilamellar vesicles (GUVs) to measure passive transport across membranes containing defined concentrations of oxidized lipid species. GUVs consisting of a saturated phospholipid, an unsaturated phospholipid, and cholesterol were used as model membranes. By replacing defined amounts of the unsaturated lipid with a corresponding oxidized product, the oxidation process could be mimicked, yielding vesicles of varying oxidized lipid concentration. Oxidized lipid concentration was varied from 0 mol% to 18 mol% of the total lipid concentration. Passive transport of PEG12-NBD, an uncharged fluorescent molecule, was measured using a microfluidic trap to capture the GUVs and spinning disk confocal microscopy (SDCM) to track the transport of a fluorescent species in the equatorial plane of each GUV. Membrane permeability was determined by fitting the resulting concentration profiles to a finite difference model of diffusion and permeation around and through the membrane. Experiments showed three permeability regimes. Without oxidation, transport was slow, with a measured permeability on the order of 1.5 × 10(-6) cm s(-1). At 2.5-10% oxidized species permeation was fast (1.5 × 10(-5) cm s(-1)). Above 12.5% oxidized species, the bilayer was disrupted by the formation of pore defects. As passive transport is an important mechanism for drug delivery, understanding the relationship between oxidation and permeation could provide insight into the pharmaceutical characteristics of tissues with oxidative damage. PMID:25415555

  15. Structural characterization of cationic lipid–tRNA complexes

    PubMed Central

    Marty, Regis; N’soukpoé-Kossi, Christophe N.; Charbonneau, David M.; Kreplak, Laurent; Tajmir-Riahi, Heidar-Ali

    2009-01-01

    Despite considerable interest and investigations on cationic lipid–DNA complexes, reports on lipid–RNA interaction are very limited. In contrast to lipid–DNA complexes where lipid binding induces partial B to A and B to C conformational changes, lipid–tRNA complexation preserves tRNA folded state. This study is the first attempt to investigate the binding of cationic lipid with transfer RNA and the effect of lipid complexation on tRNA aggregation and condensation. We examine the interaction of tRNA with cholesterol (Chol), 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), dioctadecyldimethylammoniumbromide (DDAB) and dioleoylphosphatidylethanolamine (DOPE), at physiological condition, using constant tRNA concentration and various lipid contents. FTIR, UV-visible, CD spectroscopic methods and atomic force microscopy (AFM) were used to analyze lipid binding site, the binding constant and the effects of lipid interaction on tRNA stability, conformation and condensation. Structural analysis showed lipid–tRNA interactions with G–C and A–U base pairs as well as the backbone phosphate group with overall binding constants of KChol = 5.94 (± 0.8) × 104 M–1, KDDAB = 8.33 (± 0.90) × 105 M–1, KDOTAP = 1.05 (± 0.30) × 105 M–1 and KDOPE = 2.75 (± 0.50) × 104 M–1. The order of stability of lipid–tRNA complexation is DDAB > DOTAP > Chol > DOPE. Hydrophobic interactions between lipid aliphatic tails and tRNA were observed. RNA remains in A-family structure, while biopolymer aggregation and condensation occurred at high lipid concentrations. PMID:19561199

  16. The use of the non-fasting lipid profile for lipid-lowering therapy in clinical practice - point of view.

    PubMed

    de Vries, Marijke; Klop, Boudewijn; Castro Cabezas, Manuel

    2014-06-01

    Current guidelines for the management of dyslipidaemias recommend measuring lipid profiles in the fasting state. The primary lipid targets are traditionally plasma total cholesterol and low-density lipoprotein-cholesterol (LDL-C) levels. However, triglycerides, apolipoprotein (apo) B and non-high-density lipoprotein-cholesterol (non-HDL-C) are also suitable parameters to assess cardiovascular risk and to guide lipid-lowering therapy. The advantage of the use of these variables is that they can be used in both the fasting and non-fasting state. In most cases, postprandial lipid profiles in combination with apo B are as useful as fasting lipid profiles for the differentiation between familial lipid disorders, such as heterozygous familial hypercholesterolemia, familial combined hyperlipidemia and familial hypertriglyceridemia. This article will address the interpretation, applications and limitations of a non-fasting lipid profile for daily clinical practice. PMID:24814412

  17. Hot-melt coating with lipid excipients.

    PubMed

    Jannin, Vincent; Cuppok, Yvonne

    2013-12-01

    Polymer coatings are widely used to provide drug protection, taste masking, coloration and modified drug release. Typically, coating polymers must be diluted or dispersed in solvents (water or organic) prior to coating and gliding agents are commonly added to prevent particle sticking throughout processing. Lipid excipients present an attractive alternative to standard polymer coatings as they only require melting before application directly onto the substrate. Solvent evaporation is not required; consequently powders with very high specific surface areas can be coated rapidly. A number of different lipid excipients can be used in coating and choosing the appropriate excipient for the application requires an understanding of their physico-chemical properties and its associated effect on drug release. PMID:23089578

  18. [Soluble epoxide hydrolase and lipid metabolism].

    PubMed

    Ma, Xin-Xin; Liu, Yan; Zhu, Yi

    2010-08-01

    Soluble epoxide hydrolase (sEH) is widely distributed in mammalian tissues. Epoxyeicosatrienoic acids (EETs), as metabolites of arachidonic acid, are degraded by sEH. EETs may function as antihypertensive and antiarthrosclerotic mediators for vasculature. Therefore, sEH is closely related with cardiovascular diseases and inflammation. Recent studies indicate that sEH is also involved in the regulation of lipid metabolism, and different functions of its C-terminal epoxide hydrolase domain and N-terminal phosphatase domain are revealed. Here we review the progress on the aspects of the different enzyme activity of the two terminals of sEH and the mechanisitic study on the regulation of lipid metabolism by sEH. PMID:21416942

  19. Anisotropic spontaneous curvatures in lipid membranes

    NASA Astrophysics Data System (ADS)

    Walani, Nikhil; Torres, Jennifer; Agrawal, Ashutosh

    2014-06-01

    Symmetry restrictions due to fluidity require the strain energy in the Helfrich theory of lipid membranes to be locally isotropic in nature. Although this framework is suitable for modeling the interaction of membranes with proteins that generate spherical curvature such as clathrin, there are other important membrane-bending proteins such as BIN-amphiphysin-Rvs proteins that form a cylindrical coat with different curvatures in the longitudinal and the circumferential directions. In this work, we present a detailed mathematical treatment of the theory of lipid membranes incorporating anisotropic spontaneous curvatures. We derive the associated Euler-Lagrange equations and the edge conditions in a generalized setting that allows spatial heterogeneities in the properties of the membrane-protein system. We employ this theory to model the constriction of a membrane tubule by a cylindrical scaffold. In particular, we highlight the role of the equilibrium equation in the tangential plane in regulating the spatial variation of the surface tension field.

  20. Lipid signaling: sleep, synaptic plasticity, and neuroprotection.

    PubMed

    Chen, Chu; Bazan, Nicolas G

    2005-09-01

    Increasing evidence indicates that bioactive lipids participate in the regulation of synaptic function and dysfunction. We have demonstrated that signaling mediated by platelet-activating factor (PAF) and cyclooxygenase (COX)-2-synthesized PGE2 is involved in synaptic plasticity, memory, and neuronal protection [Clark GD, Happel LT, Zorumski CF, Bazan NG. Enhancement of hippocampal excitatory synaptic transmission by platelet-activating factor. Neuron 1992; 9:1211; Kato K, Clark GD, Bazan NG, Zorumski CF. Platelet-activating factor as a potential retrograde messenger in CA1 hippocampal long-term potentiation. Nature 1994; 367:175; Izquierdo I, Fin C, Schmitz PK, et al. Memory enhancement by intrahippocampal, intraamygdala or intraentorhinal infusion of platelet-activating factor measured in an inhibitory avoidance. Proc Natl Acad Sci USA 1995; 92:5047; Chen C, Magee CJ, Bazan NG. Cyclooxygenase-2 regulates prostaglandin E2 signaling in hippocampal long-term synaptic plasticity. J Neurophysiol 2002; 87:2851]. Recently, we found that prolonged continuous wakefulness (primarily rapid eye movement (REM)-sleep deprivation, SD) causes impairments in hippocampal long-term synaptic plasticity and hippocampus-dependent memory formation [McDermott CM, LaHoste GJ, Chen C, Musto A, Bazan NG, Magee JC. Sleep deprivation causes behavioral, synaptic, and membrane excitability alterations in hippocampal neurons. J Neurosci 2003; 23:9687]. To explore the mechanisms underlying SD-induced impairments, we have studied several bioactive lipids in the hippocampus following SD. It appears that SD causes increases in prostaglandin D2 (PGD2) and 2-arachidonylglycerol (2-AG), and a decrease in PGE2, suggesting that these lipid messengers participate in memory consolidation during REM sleep. We have also explored the formation of endogenous neuroprotective lipids. Toward this aim, we have used ischemia-reperfusion damage and LC-PDA-ESI-MS-MS-based lipidomic analysis and identified docosanoids derived from synaptic phospholipid-enriched docosahexaenoic acid. Some of the docosanoids exert potent neuroprotective bioactivity [Marcheselli VL, Hong S, Lukiw WJ, et al. Novel docosanoids inhibit brain ischemia-reperfusion-mediated leukocyte infiltration and pro-inflammatory gene expression. J Biol Chem 2003; 278:43807; Mukherjee PK, Marcheselli VL, Serhan CN, Bazan, NG. Neuroprotectin D1: A docosahexaenoic acid-derived docosatriene protects human retinal pigment epithelial cells from oxidative stress. Proc Nat Acad Sci USA 2004; 101:8491). Taken together, these observations that signaling lipids participate in synaptic plasticity, cognition, and survival indicate that lipid signaling is closely associated with several functions (e.g; learning and memory, sleep, and experimental stroke) and pathologic events. Alterations in endogenous signaling lipids or their receptors resulting from drug abuse lead to changes in synaptic circuitry and induce profound effects on these important functions. In the present article, we will briefly review bioactive lipids involved in sleep, synaptic transmission and plasticity, and neuroprotection, focusing mainly on our experimental studies and how these signaling molecules are related to functions and implicated in some neurologic disorders. PMID:16099392

  1. Exercise Intensity Modulation of Hepatic Lipid Metabolism

    PubMed Central

    Lira, Fábio S.; Carnevali, Luiz C.; Zanchi, Nelo E.; Santos, Ronaldo VT.; Lavoie, Jean Marc; Seelaender, Marília

    2012-01-01

    Lipid metabolism in the liver is complex and involves the synthesis and secretion of very low density lipoproteins (VLDL), ketone bodies, and high rates of fatty acid oxidation, synthesis, and esterification. Exercise training induces several changes in lipid metabolism in the liver and affects VLDL secretion and fatty acid oxidation. These alterations are even more conspicuous in disease, as in obesity, and cancer cachexia. Our understanding of the mechanisms leading to metabolic adaptations in the liver as induced by exercise training has advanced considerably in the recent years, but much remains to be addressed. More recently, the adoption of high intensity exercise training has been put forward as a means of modulating hepatic metabolism. The purpose of the present paper is to summarise and discuss the merit of such new knowledge. PMID:22545209

  2. Exercise intensity modulation of hepatic lipid metabolism.

    PubMed

    Lira, Fábio S; Carnevali, Luiz C; Zanchi, Nelo E; Santos, Ronaldo Vt; Lavoie, Jean Marc; Seelaender, Marília

    2012-01-01

    Lipid metabolism in the liver is complex and involves the synthesis and secretion of very low density lipoproteins (VLDL), ketone bodies, and high rates of fatty acid oxidation, synthesis, and esterification. Exercise training induces several changes in lipid metabolism in the liver and affects VLDL secretion and fatty acid oxidation. These alterations are even more conspicuous in disease, as in obesity, and cancer cachexia. Our understanding of the mechanisms leading to metabolic adaptations in the liver as induced by exercise training has advanced considerably in the recent years, but much remains to be addressed. More recently, the adoption of high intensity exercise training has been put forward as a means of modulating hepatic metabolism. The purpose of the present paper is to summarise and discuss the merit of such new knowledge. PMID:22545209

  3. Lipid metabolism and hyperlipidemia in dogs.

    PubMed

    Xenoulis, Panagiotis G; Steiner, Jörg M

    2010-01-01

    Lipid metabolism in dogs can be divided into exogenous and endogenous pathways and exhibits some unique characteristics compared to other species. Hyperlipidemia is common in dogs, and can be either primary or secondary to other diseases. Secondary hyperlipidemia is the most common form and can be a result of endocrine disorders, pancreatitis, cholestasis, protein-losing nephropathy, obesity, and high fat diets. Primary hyperlipidemia is less common and usually associated with certain breeds. Hypertriglyceridemia of Miniature Schnauzers is the most common type of primary hyperlipidemia in dogs in the United States, and appears to have a genetic basis although its etiology remains unknown. Possible complications of canine hyperlipidemia include pancreatitis, liver disease, atherosclerosis, ocular disease, and seizures. Management is achieved by administration of low fat diets with or without the administration of lipid-lowering agents such as omega-3 fatty acids, gemfibrozil, and niacin. PMID:19167915

  4. Copyright 2003 by Lipid Research, Inc. This article is available online at http://www.jlr.org Journal of Lipid Research Volume 44, 2003 655

    E-print Network

    Pike, Linda J.

    ://www.jlr.org Journal of Lipid Research Volume 44, 2003 655 Lipid rafts: bringing order to chaos Linda J. Pike1 order to chaos. J. Lipid Res. 2003. 44: 655­667. Supplementary key words cholesterol · signal

  5. Parenteral lipids: safety aspects and toxicity.

    PubMed

    Wanten, Geert J A

    2015-01-01

    Lipid emulsions (LEs) used in modern parenteral nutrition formulations are indispensable sources of calories and (essential) fatty acids ((E)FAs). Several generations of LEs based on various FA sources have been developed, and issues related to their safe use deserve attention. The relevant issues concern LE composition, stability and sterility, while other problems are related to the lipid infusion rate, including hypertriglyceridemia and lipid overload syndrome. The FA structure of LEs translates into effects on inflammatory processes and immune cell function and affects the functions of organs, such as the liver and lungs. In addition, disturbed balances of (anti)oxidants and the presence of other bioactive agents in LEs, such as phytosterols, are mechanisms that may underlie the potential adverse effects. Lipid emulsions (LEs) are key components of parenteral nutrition (PN) that bypass the need for (essential) fatty acids ((E)FAs) and provide sufficient energy to decrease the need for the infusion of large amounts of dextrose, thus preventing its associated complications. The oldest available LEs are based on soybean oil (SO-LE) and meet these requirements. (Pre)clinical evidence suggests that various, next-generation LEs based on alternative oil sources are safe and effective; particularly, those based on fish oil (FO-LEs) have less pro-inflammatory characteristics that may convey beneficial effects on the immune system and organ functions. With the exception of decreased liver damage with the use of FO-LEs instead of SO-LEs, the clinical relevance of many of these data needs further validation. PMID:25471803

  6. Lipid modulation of neuronal cholinergic activity

    SciTech Connect

    Bottiglieri, D.F.

    1986-01-01

    Phospholipids are the major lipids in the plasma membrane, and it is now evident that the function of phospholipids exceeds that of the role of barrier between different aqueous compartments. Several lines of evidence suggest that a major plasma membrane lipids, phosphatidylcholine, may be a useful compound for modulating presynaptic cholinergic transmission. In order to investigate the effects of PC on cholinergic terminals, rat cortical synaptosomes were preloaded with (/sup 3/H)-ACh and then treated with small unilamellar vesicles (SUV) composed of dipalmitoylphosphatidylcholine (DPPC) at concentrations (0.8-1.5 mg/ml) similar to those found circulating in plasma. The effects of DPPC on levels, hydrolysis, release, and synthesis of (/sup 3/H)-ACh were then examined. Dipalmitoylphosphatidylcholine decreased the levels of (/sup 3/H)-ACh. This decrease does not result from a dilution of the radioactive (/sup 3/H)-choline by nonradioactive choline derived from PC. Specifically, it is the S/sub 3/ (cytoplasmic) level of (/sup 3/H)-ACh that is decreased by DPPC treatment. This decrease appears to be partially due to lipid activation of an intraterminal cholinesterase which results in hydrolysis of nonvesicular (/sup 3/H)-ACh. The ability of the lipid to interfere with exocytosis may account for the blockade of the K/sup +/ induced (/sup 3/H)-ACh release from the P/sub 3/ (vesicular) fraction. The high affinity choline transporter was competitively inhibited by DPPC treatment when synaptosomes were treated with DPPC prior to (/sup 3/H)-choline loading; the ubiquitous low affinity transport was not affected. These effects were specific for cholinergic neurons since the uptake and release of dopamine and norepinephrine from the substantia nigra and the cortex, respectively, were not affected.

  7. Dietary Lipids Impacts on Healthy Ageing

    Microsoft Academic Search

    Harumi Okuyama; Kazuyo Yamada; Daisuke Miyazawa; Yuko Yasui; Naoki Ohara

    2007-01-01

    Healthy ageing is gaining attention in the lipid nutrition field. As in vivo biomarkers of healthy ageing, we have evaluated\\u000a the survival, learning\\/memory performance, and physical potencies in rodents fed a diet supplemented with high-linoleic acid\\u000a (LNA, ?6) safflower oil or high-?-linolenic acid (ALA, ?3) perilla oil for long periods. The results suggested that perilla\\u000a oil with a low ?6\\/?3

  8. Functionalized Solid Lipid Nanoparticles for Transendothelial Delivery

    Microsoft Academic Search

    Ashwath Jayagopal; Eric M. Sussman; Venkatram Prasad Shastri

    2008-01-01

    The objectives of this study were to synthesize and characterize functionalized solid lipid nanoparticles (fSLN) to investigate their interaction with endothelial cell monolayers and to evaluate their transendothelial transport capabilities. fSLN bearing tetramethylrhodamine-isothiocyanate-labeled bovine serum albumin (TRITC-BSA) and Coumarin 6 were prepared using a single-step phase-inversion process that afforded concurrent surface modification with a variety of macromolecules such as polystyrene

  9. Evolving lipid vesicles in prebiotic hydrothermal environments

    NASA Astrophysics Data System (ADS)

    Furuuchi, Ryo; Imai, Ei-Ichi; Honda, Hajime; Hatori, Kuniyuki; Matsuno, Koichiro

    2005-08-01

    We compared three different kinds of lipid vesicles made of saturated fatty acids, unsaturated fatty acids, and phospholipids for their evolutionary capabilities in a simulated hydrothermal environment.Encapsulation of the glycine monomers enhanced the oligomerization of peptides in all cases. Fatty acid vesicles remained stable at higher temperatures and efficiently utilized heat energy for this synthetic reaction. Phospholipid vesicles were destabilized by higher temperatures, and thus were found to be better suited to enhance synthetic reactions at lower temperatures

  10. Lipid prodrug nanocarriers in cancer therapy.

    PubMed

    Mura, Simona; Bui, Duc Trung; Couvreur, Patrick; Nicolas, Julien

    2015-06-28

    Application of nanotechnology in the medical field (i.e., nanomedicine) plays an important role in the development of novel drug delivery methods. Nanoscale drug delivery systems can indeed be customized with specific functionalities in order to improve the efficacy of the treatments. However, despite the progresses of the last decades, nanomedicines still face important obstacles related to: (i) the physico-chemical properties of the drug moieties which may reduce the total amount of loaded drug; (ii) the rapid and uncontrolled release (i.e., burst release) of the encapsulated drug after administration and (iii) the instability of the drug in biological media where a fast transformation into inactive metabolites can occur. As an alternative strategy to alleviate these drawbacks, the prodrug approach has found wide application. The covalent modification of a drug molecule into an inactive precursor from which the drug will be freed after administration offers several benefits such as: (i) a sustained drug release (mediated by chemical or enzymatic hydrolysis of the linkage between the drug-moiety and its promoiety); (ii) an increase of the drug chemical stability and solubility and, (iii) a reduced toxicity before the metabolization occurs. Lipids have been widely used as building blocks for the design of various prodrugs. Interestingly enough, these lipid-derivatized drugs can be delivered through a nanoparticulate form due to their ability to self-assemble and/or to be incorporated into lipid/polymer matrices. Among the several prodrugs developed so far, this review will focus on the main achievements in the field of lipid-based prodrug nanocarriers designed to improve the efficacy of anticancer drugs. Gemcitabine (Pubchem CID: 60750); 5-fluorouracil (Pubchem CID: 3385); Doxorubicin (Pubchem CID: 31703); Docetaxel (Pubchem CID: 148124); Methotrexate (Pubchem CID: 126941); Paclitaxel (Pubchem CID: 36314). PMID:25617724

  11. Lipid signaling: Sleep, synaptic plasticity, and neuroprotection

    Microsoft Academic Search

    Chu Chen; Nicolas G. Bazan

    2005-01-01

    Increasing evidence indicates that bioactive lipids participate in the regulation of synaptic function and dysfunction. We have demonstrated that signaling mediated by platelet-activating factor (PAF) and cyclooxygenase (COX)-2-synthesized PGE2 is involved in synaptic plasticity, memory, and neuronal protection [Clark GD, Happel LT, Zorumski CF, Bazan NG. Enhancement of hippocampal excitatory synaptic transmission by platelet-activating factor. Neuron 1992; 9:1211; Kato K,

  12. Sensitive profiling of chemically diverse bioactive lipids

    Microsoft Academic Search

    Guanghou Shui; Anne K. Bendt; Kevin Pethe; Thomas Dick; Markus R. Wenk

    2007-01-01

    Here, we present an improved method for sen- sitive profiling of lipids in a single high-performance liquid chromatography-electrospray ionization-quadrupole time of flight mass spectrometry experiment. The approach con- sists of i) sensitive isocratic elution, which takes advantage of C18 column material that is resistant to increased pH values induced by piperidine, ii) chemometric alignment of mass spectra followed by differential

  13. Lipidic phase membrane protein serial femtosecond crystallography

    PubMed Central

    Johansson, Linda C; Arnlund, David; White, Thomas A; Katona, Gergely; DePonte, Daniel P; Weierstall, Uwe; Doak, R Bruce; Shoeman, Robert L; Lomb, Lukas; Malmerberg, Erik; Davidsson, Jan; Nass, Karol; Liang, Mengning; Andreasson, Jakob; Aquila, Andrew; Bajt, Sasa; Barthelmess, Miriam; Barty, Anton; Bogan, Michael J; Bostedt, Christoph; Bozek, John D; Caleman, Carl; Coffee, Ryan; Coppola, Nicola; Ekeberg, Tomas; Epp, Sascha W; Erk, Benjamin; Fleckenstein, Holger; Foucar, Lutz; Graafsma, Heinz; Gumprecht, Lars; Hajdu, Janos; Hampton, Christina Y; Hartmann, Robert; Hartmann, Andreas; Hauser, Günter; Hirsemann, Helmut; Holl, Peter; Hunter, Mark S; Kassemeyer, Stephan; Kimmel, Nils; Kirian, Richard A; Maia, Filipe R N C; Marchesini, Stefano; Martin, Andrew V; Reich, Christian; Rolles, Daniel; Rudek, Benedikt; Rudenko, Artem; Schlichting, Ilme; Schulz, Joachim; Seibert, M Marvin; Sierra, Raymond G; Soltau, Heike; Starodub, Dmitri; Stellato, Francesco; Stern, Stephan; Strüder, Lothar; Timneanu, Nicusor; Ullrich, Joachim; Wahlgren, Weixiao Y; Wang, Xiaoyu; Weidenspointner, Georg; Wunderer, Cornelia; Fromme, Petra; Chapman, Henry N; Spence, John C H; Neutze, Richard

    2012-01-01

    X-ray free electron laser (X-feL)-based serial femtosecond crystallography is an emerging method with potential to rapidly advance the challenging field of membrane protein structural biology. here we recorded interpretable diffraction data from micrometer-sized lipidic sponge phase crystals of the Blastochloris viridis photosynthetic reaction center delivered into an X-feL beam using a sponge phase micro-jet. PMID:22286383

  14. Lipidic phase membrane protein serial femtosecond crystallography.

    PubMed

    Johansson, Linda C; Arnlund, David; White, Thomas A; Katona, Gergely; Deponte, Daniel P; Weierstall, Uwe; Doak, R Bruce; Shoeman, Robert L; Lomb, Lukas; Malmerberg, Erik; Davidsson, Jan; Nass, Karol; Liang, Mengning; Andreasson, Jakob; Aquila, Andrew; Bajt, Saša; Barthelmess, Miriam; Barty, Anton; Bogan, Michael J; Bostedt, Christoph; Bozek, John D; Caleman, Carl; Coffee, Ryan; Coppola, Nicola; Ekeberg, Tomas; Epp, Sascha W; Erk, Benjamin; Fleckenstein, Holger; Foucar, Lutz; Graafsma, Heinz; Gumprecht, Lars; Hajdu, Janos; Hampton, Christina Y; Hartmann, Robert; Hartmann, Andreas; Hauser, Günter; Hirsemann, Helmut; Holl, Peter; Hunter, Mark S; Kassemeyer, Stephan; Kimmel, Nils; Kirian, Richard A; Maia, Filipe R N C; Marchesini, Stefano; Martin, Andrew V; Reich, Christian; Rolles, Daniel; Rudek, Benedikt; Rudenko, Artem; Schlichting, Ilme; Schulz, Joachim; Seibert, M Marvin; Sierra, Raymond G; Soltau, Heike; Starodub, Dmitri; Stellato, Francesco; Stern, Stephan; Strüder, Lothar; Timneanu, Nicusor; Ullrich, Joachim; Wahlgren, Weixiao Y; Wang, Xiaoyu; Weidenspointner, Georg; Wunderer, Cornelia; Fromme, Petra; Chapman, Henry N; Spence, John C H; Neutze, Richard

    2012-03-01

    X-ray free electron laser (X-FEL)-based serial femtosecond crystallography is an emerging method with potential to rapidly advance the challenging field of membrane protein structural biology. Here we recorded interpretable diffraction data from micrometer-sized lipidic sponge phase crystals of the Blastochloris viridis photosynthetic reaction center delivered into an X-FEL beam using a sponge phase micro-jet. PMID:22286383

  15. Binding of a Fluorescent Lipid Amphiphile to Albumin and its Transfer to Lipid Bilayer Membranes

    PubMed Central

    Abreu, Magda S. C.; Estronca, Luís M. B. B.; Moreno, Maria Joăo; Vaz, Winchil L. C.

    2003-01-01

    Kinetics and thermodynamics of the binding of a fluorescent lipid amphiphile, Rhodamine Green™-tetradecylamide (RG-C14:0), to bovine serum albumin were characterized in an equilibrium titration and by stopped-flow fluorimetry. The binding equilibrium of RG-C14:0 to albumin was then used to reduce its concentration in the aqueous phase to a value below its critical micelle concentration. Under these conditions, the only two species of RG-C14:0 in the system were the monomer in aqueous solution in equilibrium with the protein-bound species. After previous determination of the kinetic and thermodynamic parameters for association of RG-C14:0 with albumin, the kinetics of insertion of the amphiphile into and desorption off lipid bilayer membranes in different phases (solid, liquid-ordered, and liquid-disordered phases, presented as large unilamellar vesicles) were studied by stopped-flow fluorimetry at 30°C. Insertion and desorption rate constants for association of the RG-C14:0 monomer with the lipid bilayers were used to obtain lipid/water equilibrium partition coefficients for this fluorescent amphiphile. The direct measurement of these partition coefficients is shown to provide a new method for the indirect determination of the equilibrium partition coefficient of similar molecules between two defined lipid phases if they coexist in the same membrane. PMID:12524292

  16. 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

  17. Effects of fenofibrate on bile lipid composition.

    PubMed

    Palmer, R H

    1985-01-01

    In humans, clofibrate increases the degree of bile cholesterol saturation and predisposes patients to cholesterol gallstone formation. To determine if this activity extends to the related hypolipidemic agent fenofibrate, duodenal bile lipid composition was studied in 15 subjects before they participated in a double-blind study of that drug. Eight subjects were studied again on fenofibrate and six on placebo; five placebo patients were also studied later on open-label fenofibrate. The results were similar in the double-blind and open-label studies, and changes in bile lipid composition were comparable to those seen in studies of clofibrate. Fenofibrate caused a significant decrease in the molar percentage of bile acids and increases in the molar percentage of phospholipids and cholesterol. The changes in bile acids and phospholipids had opposing effects on the cholesterol-holding capacity of bile. A statistically significant increase in the cholesterol saturation index was only apparent when all fenofibrate bile analyses were compared with all untreated bile analyses. The results demonstrated that fenofibrate has clear effects on bile lipid composition that may be associated with an increased propensity for gallstone formation, and when fenofibrate is used, patients should be monitored for this possibility. PMID:4074196

  18. Microorganism lipid droplets and biofuel development

    PubMed Central

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

    2013-01-01

    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. [BMB Reports 2013; 46(12): 575-581] PMID:24355300

  19. Dynamic regulation of lipid-protein interactions.

    PubMed

    Martfeld, Ashley N; Rajagopalan, Venkatesan; Greathouse, Denise V; Koeppe, Roger E

    2015-09-01

    We review the importance of helix motions for the function of several important categories of membrane proteins and for the properties of several model molecular systems. For voltage-gated potassium or sodium channels, sliding, tilting and/or rotational movements of the S4 helix accompanied by a swapping of cognate side-chain ion-pair interactions regulate the channel gating. In the seven-helix G protein-coupled receptors, exemplified by the rhodopsins, collective helix motions serve to activate the functional signaling. Peptides which initially associate with lipid-bilayer membrane surfaces may undergo dynamic transitions from surface-bound to tilted-transmembrane orientations, sometimes accompanied by changes in the molecularity, formation of a pore or, more generally, the activation of biological function. For single-span membrane proteins, such as the tyrosine kinases, an interplay between juxtamembrane and transmembrane domains is likely to be crucial for the regulation of dimer assembly that in turn is associated with the functional responses to external signals. Additionally, we note that experiments with designed single-span transmembrane helices offer fundamental insights into the molecular features that govern protein-lipid interactions. This article is part of a Special Issue entitled: Lipid-protein interactions. PMID:25666872

  20. Stiffened lipid platforms at molecular force foci

    PubMed Central

    Anishkin, Andriy; Kung, Ching

    2013-01-01

    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

  1. 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.

  2. Syringomycin E channel: a lipidic pore stabilized by lipopeptide?

    PubMed Central

    Malev, Valery V; Schagina, Ludmila V; Gurnev, Philip A; Takemoto, Jon Y; Nestorovich, Ekaterina M; Bezrukov, Sergey M

    2002-01-01

    Highly reproducible ion channels of the lipopeptide antibiotic syringomycin E demonstrate unprecedented involvement of the host bilayer lipids. We find that in addition to a pronounced influence of lipid species on the open-channel ionic conductance, the membrane lipids play a crucial role in channel gating. The effective gating charge, which characterizes sensitivity of the conformational equilibrium of the syringomycin E channels to the transmembrane voltage, is modified by the lipid charge and lipid dipolar moment. We show that the type of host lipid determines not only the absolute value but also the sign of the gating charge. With negatively charged bilayers, the gating charge sign inverts with increased salt concentration or decreased pH. We also demonstrate that the replacement of lamellar lipid by nonlamellar with the negative spontaneous curvature inhibits channel formation. These observations suggest that the asymmetric channel directly incorporates lipids. The charges and dipoles resulting from the structural inclusion of lipids are important determinants of the overall energetics that underlies channel gating. We conclude that the syringomycin E channel may serve as a biophysical model to link studies of ion channels with those of lipidic pores in membrane fusion. PMID:11916856

  3. 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

  4. Thermal Adaptation of the Archaeal and Bacterial Lipid Membranes

    PubMed Central

    Koga, Yosuke

    2012-01-01

    The physiological characteristics that distinguish archaeal and bacterial lipids, as well as those that define thermophilic lipids, are discussed from three points of view that (1) the role of the chemical stability of lipids in the heat tolerance of thermophilic organisms: (2) the relevance of the increase in the proportion of certain lipids as the growth temperature increases: (3) the lipid bilayer membrane properties that enable membranes to function at high temperatures. It is concluded that no single, chemically stable lipid by itself was responsible for the adaptation of surviving at high temperatures. Lipid membranes that function effectively require the two properties of a high permeability barrier and a liquid crystalline state. Archaeal membranes realize these two properties throughout the whole biological temperature range by means of their isoprenoid chains. Bacterial membranes meet these requirements only at or just above the phase-transition temperature, and therefore their fatty acid composition must be elaborately regulated. A recent hypothesis sketched a scenario of the evolution of lipids in which the “lipid divide” emerged concomitantly with the differentiation of archaea and bacteria. The two modes of thermal adaptation were established concurrently with the “lipid divide.” PMID:22927779

  5. Lipid-like self-assembling peptides.

    PubMed

    Zhang, Shuguang

    2012-12-18

    One important question in prebiotic chemistry is the search for simple structures that might have enclosed biological molecules in a cell-like space. Phospholipids, the components of biological membranes, are highly complex. Instead, we looked for molecules that might have been available on prebiotic Earth. Simple peptides with hydrophobic tails and hydrophilic heads that are made up of merely a combination of these robust, abiotically synthesized amino acids and could self-assemble into nanotubes or nanovesicles fulfilled our initial requirements. These molecules could provide a primitive enclosure for the earliest enzymes based on either RNA or peptides and other molecular structures with a variety of functions. We discovered and designed a class of these simple lipid-like peptides, which we describe in this Account. These peptides consist of natural amino acids (glycine, alanine, valine, isoleucine, leucine, aspartic acid, glutamic acid, lysine, and arginine) and exhibit lipid-like dynamic behaviors. These structures further undergo spontaneous assembly to form ordered arrangements including micelles, nanovesicles, and nanotubes with visible openings. Because of their simplicity and stability in water, such assemblies could provide examples of prebiotic molecular evolution that may predate the RNA world. These short and simple peptides have the potential to self-organize to form simple enclosures that stabilize other fragile molecules, to bring low concentration molecules into a local environment, and to enhance higher local concentration. As a result, these structures plausibly could not only accelerate the dehydration process for new chemical bond formation but also facilitate further self-organization and prebiotic evolution in a dynamic manner. We also expect that this class of lipid-like peptides will likely find a wide range of uses in the real world. Because of their favorable interactions with lipids, these lipid-like peptides have been used to solubilize and stabilize membrane proteins, both for scientific studies and for the fabrication of nanobiotechological devices. They can also increase the solubility of other water-insoluble molecules and increase long-term stability of some water-soluble proteins. Likewise, because of their lipophilicity, these structures can deliver molecular cargo, such as small molecules, siRNA, and DNA, in vivo for potential therapeutic applications. PMID:22720818

  6. Radiation-induced lipid peroxidation and the fluidity of erythrocyte membrane lipids

    SciTech Connect

    Guille, J.; Raison, J.K.; Gebicki, J.M.

    1987-01-01

    The effect of radiation-induced peroxidation on the fluidity of the phospholipids of the erythrocyte membrane was studied using both erythrocyte ghosts and liposomes formed from the polar lipids of erythrocytes. In liposomes, the oxidation of the phospholipids increased with radiation dose, but there was no change in the fluidity of the lipids as measured by spin-label motion. Under the same conditions of irradiation, no oxidation of phospholipid was detected in erythrocyte ghosts, although changes occurred in the motion of spin labels intercalated with the membrane. These changes were attributed to radiation-induced alterations in the membrane proteins. It is concluded that alterations in motion of spin labels, observed with intact membranes after irradiation, are most likely the result of changes in the structure of membrane proteins rather than the lipids.

  7. [Lipids, lipoproteins, arterial accidents and oral contraceptives].

    PubMed

    Bakir, R; Hilliquin, P

    1986-01-01

    This work reviews lipoprotein metabolism and relationships to atherosclerosis, examines the nature of arterial accidents and lipid modifications that occur with oral contraceptive (OC) use, and assesses the practical consequences for OC prescription. Cholesterol, triglycerides, and phospholipids are not soluble in aqueous milieus, and their transport in plasma is provided by macromolecules comprising a protein part and a lipid part. 5 types of these lipoproteins are distinguished by their relative richness in lipids and protein and by the nature of their proteins. The chylomicrons carry exogenous triglycerides to the peripheral tissues and cholesterol of dietary origin to the liver. Very low density lipoprotein (VLDL) cholesterol is secreted by the liver and transports triglycerides and cholesterol of endogenous origin. Low denisty lipoprotein (LDL) cholesterol originates in the degradation of VLDL cholesterol and transports cholesterol to the cells. High density lipoprotein (HDL) cholesterol is secreted by the liver and intestines or formed in the course of degradation of chylomicrons and VLDL cholesterol. Its role is to carry excess cholesterol in the peripheral tissues to the liver for elimination in the bile. Cholesterol thus follows 2 different pathways in the body: a path from the liver to the peripheral cells, whose markers are LDL and VLDL cholesterol and the plasma apoprotein B, and a path of return of excess cholesterol from the tissues and especially the arteries to the liver, marked by HDL cholesterol and the plasma apoprotein A. Only a proper balance between the 2 flows can prevent an excess of cholesterol in the arteries and the consequent constitution of atherosclerotic lesions. LDL and to a lesser extent VLDL cholesterol are strongly and positively correlated to atherogenic risk, while HDL cholesterol is negatively correlated to risk, independently of other risk factors. Arterial accidents occurring with OC use do not seem to be atheromatous in nature. A study by the Lipid Research Clinics of 2000 OC users and nonusers found that users had higher levels of total cholesterol, of triglycerides, and of LDL and VLDL cholesterol, while the elevation of HDL cholesterol was minimal. The effects of combinations of hormones in OCs depend on their composition. OCs with high or medium doses of estrogen cause an elevation in total cholesterol, triglycerides, and LDL and VLDL cholesterol. HDL cholesterol rises slightly with 19 norsteroids and declines with norgestrel. The ratio of total to HDL cholesterol is on the whole increased. OCs with low estrogen doses induce a decline inHDL cholesterol while the levels of total cholesterol and triglycerides remain unchanged. High dose progestin-only pills induce increases in LDL and decreases in HDL cholestrol. Total cholesterol tends to increases with 19 norsteroids and decline with noregestrel while triglycerides vary slightly. With smaller doses of progestin, less intense effects may be seen. The theoretic atherogenic risk determined by the levels and ratio of total and HDL cholesterol is thus increased with some hormonal combinations. OCs can be prescribed for women with normal lipid balance after a pretreatment lipid profile determination. Lipid balance should be reassessed regularly. OCs are contraindicated in cases of moderate or severe hypercholesterolemia and primary hypo HDLemia. Combined OCs may be used in cases of mild hyperlipoproteinemia in which other contraceptive methods are not possible if regular monitoring is provided. PMID:12341243

  8. Effects of Ferulago angulata Extract on Serum Lipids and Lipid Peroxidation

    PubMed Central

    Rafieian-kopaei, Mahmoud; Shahinfard, Najmeh; Rouhi-Boroujeni, Hojjat; Gharipour, Mojgan; Darvishzadeh-Boroujeni, Pariya

    2014-01-01

    Background. Nowadays, herbs they are considered to be the main source of effective drugs for lowering serum lipids and lipid peroxidation. The present experimental animal study aimed to assess the impact of Ferulago angulata on serum lipid profiles, and on levels of lipid peroxidation. Methods. Fifty male Wistar rats, weighing 250–300?g, were randomly divided into five equal groups (ten rats in each). The rat groups received different diets as follows: Group I: fat-rich diet; Group II: fat-rich diet plus hydroalcoholic extracts of Ferulago angulata at a dose of 400?mg/kg; Group III: fat-rich diet plus hydroalcoholic extracts of Ferulago angulata at a dose of 600?mg/kg; Group IV: fat-rich diet plus atorvastatin; Group V: common stock diet. The levels of serum glucose and lipids and the atherogenic index were measured. In addition, malondialdehyde (MDA), thiol oxidation, carbonyl concentrations, C-reactive proteins, and antioxidant capacity were evaluated in each group of rats. Results. Interestingly, by adding a hydroalcoholic extract of Ferulago angulata to the high-fat diet, the levels of total cholesterol and low-density lipoproteins (LDL) in the high-fat diet rats were both significantly reduced. This result was considerably greater compared to when atorvastatin was added as an antilipid drug. The beneficial effects of the Ferulago angulata extract on lowering the level of triglycerides was observed only when a high dosage of this plant extraction was added to a high fat diet. Furthermore, the level of malondialdehyde, was significantly affected by the use of the plant extract in a high-fat diet, compared with a normal regimen or high-fat diet alone. Conclusion. Administration of a hydroalcoholic extract of Ferulago angulata can reduce serum levels of total cholesterol, triglycerides, and LDL. It can also inhibit lipid peroxidation. PMID:24707310

  9. 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

  10. Integration of a K+ channel-associated peptide in a lipid bilayer: conformation, lipid-protein interactions, and rotational diffusion.

    PubMed

    Horváth, L I; Heimburg, T; Kovachev, P; Findlay, J B; Hideg, K; Marsh, D

    1995-03-28

    The 26-residue peptide of sequence KEALYILMVLGFFGFFTLGIMLSYIR, which contains the single putative transmembrane domain of a small protein that is associated with slow voltage-gated K+ channels, has been incorporated in bilayers of dimyristoylphosphatidylcholine by dialysis from 2-chloroethanol to form complexes of homogeneous lipid/peptide ratio. Fourier transform infrared spectroscopy indicates that the peptide is integrated in the lipid bilayer wholly in a beta-sheet conformation. The electron spin resonance spectra of spin-labeled lipids in the lipid/peptide complexes contain a component corresponding to lipids whose chains are motionally restricted in a manner similar to those of lipids at the hydrophobic surface of integral transmembrane proteins. From the dependence of the lipid spin label spectra on the lipid/peptide ratio of the complexes, it is found that ca. 2.5 lipids per peptide monomer, independent of the species of spin-labeled lipid, are motionally restricted by direct interaction with the peptide in the bilayer. This value would be consistent with, e.g., a beta-barrel structure for the peptide in which the beta-strands either are strongly tilted or have a reverse turn at their center. A preferential selectivity of interaction with the peptide is observed for the negatively charged spin-labeled lipids phosphatidic acid, stearic acid, and phosphatidylserine, which indicates close proximity of the positively charged residues at the peptide termini to the lipid headgroups. The saturation-transfer electron spin resonance spectra of the peptide spin-labeled at a cysteine residue replacing Leu18 evidence rather slow rotational diffusion in the lipid complexes.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7696252

  11. Enhanced lipid extraction from algae using free nitrous acid pretreatment.

    PubMed

    Bai, Xue; Naghdi, Forough Ghasemi; Ye, Liu; Lant, Paul; Pratt, Steven

    2014-05-01

    Lipid extraction has been identified as a major bottleneck for large-scale algal biodiesel production. In this work free nitrous acid (FNA) is presented as an effective and low cost pretreatment to enhance lipid recovery from algae. Two batch tests, with a range of FNA additions, were conducted to disrupt algal cells prior to lipid extraction by organic solvents. Total accessible lipid content was quantified by the Bligh and Dyer method, and was found to increase with pretreatment time (up to 48 h) and FNA concentration (up to 2.19 mg HNO2-N/L). Hexane extraction was used to study industrially accessible lipids. The mass transfer coefficient (k) for lipid extraction using hexane from algae treated with 2.19 mg HNO2-N/L FNA was found to be dramatically higher than for extraction from untreated algae. Consistent with extraction results, cell disruption analysis indicated the disruption of the cell membrane barrier. PMID:24632439

  12. Apoptosis-induced mitochondrial dysfunction causes cytoplasmic lipid droplet formation

    PubMed Central

    Boren, J; Brindle, K M

    2012-01-01

    A characteristic of apoptosis is the rapid accumulation of cytoplasmic lipid droplets, which are composed largely of neutral lipids. The proton signals from these lipids have been used for the non-invasive detection of cell death using magnetic resonance spectroscopy. We show here that despite an apoptosis-induced decrease in the levels and activities of enzymes involved in lipogenesis, which occurs downstream of p53 activation and inhibition of the mTOR signaling pathway, the increase in lipid accumulation is due to increased de novo lipid synthesis. This results from inhibition of mitochondrial fatty acid ?-oxidation, which coupled with an increase in acyl-CoA synthetase activity, diverts fatty acids away from oxidation and into lipid synthesis. The inhibition of fatty acid oxidation can be explained by a rapid rise in mitochondrial membrane potential and an attendant increase in the levels of reactive oxygen species. PMID:22460322

  13. Lipid nanoparticles for the topical delivery of retinoids and derivatives.

    PubMed

    Morales, Javier O; Valdés, Karina; Morales, Javier; Oyarzun-Ampuero, Felipe

    2015-01-01

    Retinoids are lipophilic compounds that are highly used in cosmetics/therapeutics for skin disorders. Conventional formulations are limited by poor water solubility, high chemical/photochemical instability and the irritation of retinoids. Interestingly, lipid nanoparticles enable the administration of retinoids in aqueous media, providing drug stabilization and controlled release. Recently, it has been demonstrated that retinoids in solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and nanocapsules can decrease degradation, improve targeting and enhance efficacy for the treatment of skin disorders. This article focuses on the formulation, fabrication, characterization and in vitro/in vivo evaluation of solid lipid nanoparticles, nanostructured lipid carriers, nanoemulsions and nanocapsules loaded with retinoids for skin administration. Furthermore, the incorporation of these lipid nanoparticles into secondary vehicles is discussed. PMID:25600970

  14. Insect endosymbiont proliferation is limited by lipid availability

    PubMed Central

    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. DOI: http://dx.doi.org/10.7554/eLife.02964.001 PMID:25027439

  15. 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

  16. Polyunsaturated Fatty Acids in Lipid Bilayers and Tubules

    NASA Astrophysics Data System (ADS)

    Hirst, Linda S.; Yuan, Jing; Pramudya, Yohannes; Nguyen, Lam T.

    2007-03-01

    Omega-3 polyunsaturated fatty acids (PUFAs) are found in a variety of biological membranes and have been implicated with lipid raft formation and possible function, typical molecules include DHA (Docosahexanoic Acid) and AA (Alphalinoleic Acid) which have been the focus of considerable attention in recent years. We are interested in the phase behavior of these molecules in the lipid bilayer. The addition of lipid molecules with polyunsaturated chains has a clear effect on the fluidity and curvature of the membrane and we investigate the effects the addition of polyunsaturated lipids on bilayer structure and tubule formation. Self-assembled cylindrical lipid tubules have attracted considerable attention because of their interesting structures and potential technological applications. Using x-ray diffraction techniques, Atomic Force Microscopy and confocal fluorescence imaging, both symmetric and mixed chain lipids were incorporated into model membranes and the effects on bilayer structure and tubule formation investigated.

  17. Antioxidative effect of sesamol and related compounds on lipid peroxidation.

    PubMed

    Uchida, M; Nakajin, S; Toyoshima, S; Shinoda, M

    1996-04-01

    The effect of sesamol and 20 related compounds on the lipid peroxidation of liposomes induced by Fe(2)+, on the lipid peroxidation of rat liver microsomes induced by CCl(4) or NADPH and on the lipid peroxidation of mitochondria induced by ascorbate/Fe(2)+ were demonstrated. Consequently, sesamol and related compounds, such as 3-methoxy-4-hydroxyquinone, isosafrol, isoeugenol, eugenol, 3,4-methylenedioxyaniline, catechol, hydroxy-hydroquinone, 3,4-dimethoxyaniline and caffeic acid, exhibited powerful inhibitory effects on the lipid peroxidation system investigated. In particular, isoeugenol was the most powerful inhibitor among all the sesamol-related compounds tested on the lipid peroxidation system. In addition, 1,2-methylenedioxybenzene, ferulic acid, and 3,4-methylenedioxynitrobenzene were also effective on the lipid peroxidation system of liposomes induced by Fe(2)+. The correlation between the structures of sesamol-related compounds and their inhibitory effect is discussed. PMID:9132170

  18. Characterization of Lipid Components in Two Microalgae for Biofuel Application

    Microsoft Academic Search

    Guang WangTong Wang; Tong Wang

    A full characterization of lipid components is critical for selecting the most suitable microalgae and for downstream processing\\u000a for biofuel production. This study demonstrates extraction, quantification, and diversity of lipid components from two microalgae\\u000a of different types. For total lipid quantification, three extraction methods were compared and the method of pre-drying, dry\\u000a ice-assisted grinding, and sequential solvent extraction gave the

  19. Marine lipid-based liposomes increase in vivo FA bioavailability

    Microsoft Academic Search

    Maud Cansell; Fabienne Nacka; Nicole Combe

    2003-01-01

    Liposomes made from an extract of natural marine lipids and containing a high n-3 PUFA lipid ratio were envisaged as oral\\u000a route vectors for FA supplements in order to increase PUFA bioavailability. The absorption of FA in thoracic lymph duct-cannulated\\u000a rats, after intragastric feeding of dietary fats in the form of liposomes or fish oil, was compared. Lipid and FA

  20. Lipid composition of yeastlike cells of the fungus Pullularia pullulans

    Microsoft Academic Search

    J. Pontón; P. Regúlez; J. B. Domínguez; F. M. Gońi; F. Uruburu

    1980-01-01

    AlthoughPullularia pullulans is a polymorphic fungus, cultures have been obtained consisting exclusively of yeastlike cells. These cells can be considered\\u000a as “medium lipid content” yeasts (5.7%). Thirty percent of the total lipids are phosphoglycerides, the most abundant of which\\u000a are phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. The bulk of the nonpolar lipids is made up of unsaponifiable\\u000a matter, sterols, and hydrocarbons. Eighteen

  1. Statin therapy in peritoneal dialysis patients: effects beyond lipid lowering

    Microsoft Academic Search

    Kosmas I. Paraskevas

    2008-01-01

    Lipid abnormalities, and especially hypertriglyceridaemia, are a prominent feature of peritoneal dialysis (PD) patients. The\\u000a results from several studies have shown that statins are effective and safe lipid-lowering agents in these individuals. Besides\\u000a lipid lowering, current evidence suggests that these agents exert multiple beneficial effects on PD patients. Statins may\\u000a maintain residual kidney function by altering the response of the

  2. Proton magnetic resonance imaging of lipid in pecan embryos

    Microsoft Academic Search

    John M. Halloina; Thomas G. Cooper; E. James Potchen; Tommy E. Thompson

    1993-01-01

    Magnetic resonance images of plant tissues typically are manifestations of water protons in tissues. Within oilseeds, however,\\u000a lipids contain a major portion of the mobile protons, which should enable specific imaging of lipids. In this study, experiments\\u000a were done to demonstrate spin-echo imaging (SEI) and chemical-shift imaging (CSI) of lipid within nonimbibed and imbibed embryos\\u000a of pecan (Carya illinoensis), a

  3. Lipid profiling of the model temperate grass, Brachypodium distachyon

    Microsoft Academic Search

    M. Nurul Islam; John P. Chambers; Carl K.-Y. Ng

    Lipids are essential metabolites in cells and they fulfil a variety of functions, including structural components of cellular\\u000a membranes, energy storage, cell signalling, and membrane trafficking. In plants, changes in lipid composition have been observed\\u000a in diverse responses ranging from abiotic and biotic stress to organogenesis. Knowledge of the lipid composition is an important\\u000a first step towards understanding the function

  4. Highly hydrated deformable polyethylene glycol-tethered lipid bilayers.

    PubMed

    Hertrich, Samira; Stetter, Frank; Rühm, Adrian; Hugel, Thorsten; Nickel, Bert

    2014-08-12

    The realization of a solid-supported lipid bilayer acting as a workbench for the study of membrane processes is a difficult task. For robustness, the bilayer has to be tethered to the substrate. At the same time, diffusion of the lipids and plastic deformations of the membrane should not be obstructed. Furthermore, a highly hydrated surrounding is mandatory. Here, we show that grafting of a polyethylene glycol-lipid construct (PEG2000-DSPE) to a silicon oxide surface via multiple-step silane chemistry and subsequent deposition of lipids by spin-coating result in a cushioned membrane that has the desired properties. Neutron and X-ray reflectometry measurements are combined to access thickness, density, and hydration of the bilayer and the PEG cushion. We observe a spacer of 55 Ĺ thickness between lipid bilayer and silicon-oxide surface with a rather high hydration of up to 90 ± 3% water. While 11.5 ± 3% of the lipids are grafted to the surface, as determined from the neutron data, the diffusion constant of the lipids, as probed by diffusion of 0.5% Texas Red labeled lipids, remains rather large (D = 2.1 ± 0.1 ?m(2)/s), which is a reduction of only 12% compared to a supported lipid bilayer reference without immobilized lipids. Finally, AFM indentation confirms the plastic behavior of the membrane against deformation. We show that rupture of the bilayer does not occur before the deformation exceeds 40 Ĺ. Altogether, the presented PEG-tethered lipid bilayer mimics the deformability of natural cell membranes much better than standard solid-supported lipid bilayers. PMID:25046694

  5. Challenges in the theoretical investigations of lipid membrane configurations

    NASA Astrophysics Data System (ADS)

    Tu, Zhan-Chun

    2013-02-01

    We report some key results in the theoretical investigations of configurations of lipid membranes and present several challenges in this field, which involve (i) the exact solutions to the shape equation of lipid vesicles, (ii) the exact solutions to the governing equations of open lipid membranes, (iii) the neck condition of two-phase vesicles in the budding state, (iv) the nonlocal theory of membrane elasticity, and (v) the relationship between the symmetry and the magnitude of the free energy.

  6. Structure and Interactions in Polypeptide Cationic Lipid Complexes

    Microsoft Academic Search

    G. Subramanian; R. P. Hjelm; G. S. Smith; C. R. Safinya

    1998-01-01

    Complexes of polypeptides and cationic lipids have elicited much interest recently because of their potential in developing novel biomolecular materials. We have investigated the solution structure of complexes made from the anionic polypeptide poly-L-glutamic acid (PGA), the cationic lipid DDAB, and the neutral lipid DLPC. X-ray scattering and SANS revealed the structure of the complexes to be multilamellar in nature

  7. Metal-catalyzed oxidation in mackerel skin and meat lipids

    Microsoft Academic Search

    P. J. Ke; R. G. Ackman

    1976-01-01

    Kinetic effects of added copper, zinc, and iron compounds have been investigated in the oxidation of lipids in mackerel skin\\u000a and meat at 60 C using a simple weight gain method. Inorganic Fe(II) and Cu(II) were found to be strong catalysts in mackerel\\u000a lipid oxidation. The meat lipids were particularly sensitive to oxidation in the presence of Fe(II) and Cu(II)

  8. Nile red: a selective fluorescent stain for intracellular lipid droplets

    Microsoft Academic Search

    PHILLIP GREENSPAN; EUGENE P. MAYER; STANLEY D. FOWLER

    1985-01-01

    We report that the dye nile red, 9-diethylamino-5H-benzo(a)phenoxazine-5-one, is an excellent vital stain for the detection of intracellular lipid droplets by fluorescence microscopy and flow cytofluorometry. The specificity of the dye for lipid droplets was assessed on cultured aortic smooth muscle cells and on cultured peritoneal macrophages that were incubated with acetylated low density lipoprotein to induce cytoplasmic lipid overloading.

  9. 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...

  10. Rapid Method for the Quantitative Extraction and Simultaneous Class Separation of Milk Lipids

    Microsoft Academic Search

    Robert J. Maxwell; Donna Mondimore; Joseph Tobias

    1986-01-01

    A method is described for the isolation of lipids from milk, cream, or buttermilk. Lipid isolation is accomplished by solvent elution of a column containing a mixture of the milk product, anhydrous sodium sulfate, and Celite 545. Total lipids are isolated by elution with a 90:10 mixture of dichloromethane: methanol. Aherna- tively, lipids may be separated into a neutral lipid

  11. 21 CFR 862.1470 - Lipid (total) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...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)...

  12. 21 CFR 862.1470 - Lipid (total) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...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)...

  13. 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

  14. 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

  15. Label-Free Sensing on Supported Lipid Bilayers 

    E-print Network

    Robison, Aaron Douglas 1982-

    2012-11-28

    ....................................................................................... 1 Supported Lipid Bilayers .............................................................. 5 Microfluidics and Flow Cells ........................................................ 7 II EXPERIMENTAL SECTION... .................................... 13 Preparation of Glass Substrates ...................................................... 13 Fabrication of Microfluidic Devices .............................................. 15...

  16. Lipid composition of plant mitochondria and of chloroplasts.

    PubMed

    Schwertner, H A; Biale, J B

    1973-03-01

    The mitochondrial lipids from avocado fruit, cauliflower buds, and potato tubers, and the lipids of chloroplasts isolated from avocado fruit and from cauliflower leaves were identified and the concentrations were determined. The lipid composition was compared with that of beef heart mitochondria. Phospholipids constituted 50-56% of total lipids in plant mitochondria while this fraction made up 90% of the lipids in beef heart mitochondria. In both cases the chief phospholipids were phosphatidylcholine and phosphatidylethanolamine. A characteristic feature of plant mitochondria was the presence of monogalactosyl- and digalactosyldiglyceride and of sulfolipid. Potato mitochondria differed from the particles of other species investigated by their higher content of galactolipids, sterol glycosides, and carotenoids and lower content of phospholipids and of total lipids in the lipidprotein complex. The galactolipid content was markedly higher in chloroplasts from all sources than in mitochondria. The spectrum of lipids in the phospholipid fraction differed more strikingly between chloroplasts of the leaf and the mitochondria of the bud of cauliflower than between the two organelles of the avocado mesocarp. The fatty acid distribution of individual lipids and of classes of lipids was also more similar in the two organelles of the fruit tissue than in the cauliflower material. PMID:4698270

  17. Role of ABC transporters in lipid transport and human disease

    PubMed Central

    Tarling, Elizabeth J.; de Aguiar Vallim, Thomas Q.; Edwards, Peter A.

    2013-01-01

    Almost half of the 48 human ATP binding cassette (ABC) transporter proteins are thought to facilitate the ATP-dependent translocation of lipids or lipid-related compounds. Such substrates include cholesterol, plant sterols, bile acids, phospholipids and sphingolipids. Mutations in a substantial number of the 48 human ABC transporters have been linked to human disease. Indeed the finding that 12 diseases have been associated with abnormal lipid transport and/or homeostasis, demonstrates the importance of this family of transporters in cell physiology. This review highlights the role of ABC transporters in lipid transport and movement, in addition to discussing their roles in cellular homeostasis and inherited disorders. PMID:23415156

  18. 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

  19. Highlights of recent progress in plant lipid research.

    PubMed

    Lessire, R; Cahoon, E; Chapman, K; Dyer, J; Eastmond, P; Heinz, E

    2009-06-01

    Raw fossil material reserves are not inexhaustible and as prices continue to raise it is necessary to find new sources of alternative and renewable energy. Oils from oleaginous field crops (sunflower and rape) with properties close to those of fossil fuel could constitute an alternative source of energy for the production of raw materials. This is the context in which the 18th International Symposium on Plant lipids (ISPL) was held in Bordeaux from 20th to 25th July 2008 at "La Cité Mondiale". The 18th ISPL gathered 270 researchers from 33 countries. Sixty nine oral communications and 136 posters were presented during the 12 sessions of the Symposium. The sessions have covered all the different aspects of the Plant Lipid field including: Surface lipids: suberin, cutin and waxes, Fatty acids, Glycerolipids, Plant lipids as renewable sources of energy, Seed oils and bioengineering of metabolic pathways, Lipid catabolism, Models for lipid studies: lower plants, micro-organisms and others, Modifications of proteins by lipids, Sphingolipids, sterols and isoprenoids, Lipid signaling and plant stress responses, Lipid trafficking and membrane dynamics, New methods and technologies: functional lipidomics, fluxome, modelling. During the ISPL 2008 Bordeaux, important and new information was reported in the different fields. A selection of these results is presented here. PMID:19328004

  20. Using Monomolecular Films to Characterize Lipid Lateral Interactions

    PubMed Central

    Brown, Rhoderick E.; Brockman, Howard L.

    2008-01-01

    Summary Membrane lipids are structurally diverse in ways that far exceed the role envisioned by Singer and Nicholson of simply providing a fluid bilayer matrix in which proteins reside. Current models of lipid organization in membranes postulate that lipid structural diversity enables nonrandom lipid mixing in each leaflet of the bilayer, resulting in regions with special physical and functional properties, i.e., microdomains. Central to understanding the tendencies of membrane lipids to mix nonrandomly in biomembranes is the identification and evaluation of structural features that control membrane lipid lateral mixing interactions in simple model membranes. The surface balance provides a means to evaluate the lateral interactions among different lipids at a most fundamental level—mixed in binary/ternary combinations that self-assemble at the air–water interface as monomolecular films, i.e., monolayers. Analysis of surface pressure and interfacial potential as a function of average cross-sectional molecular area provide insights into hydrocarbon chain ordering, lateral compressibility/elasticity, and dipole effects under various conditions including those that approximate one leaflet of a bilayer. Although elegantly simple in principle, effective use of the surface balance requires proper attention to various experimental parameters, which are described herein. Adequate attention to these experimental parameters ensures that meaningful insights are obtained into the lipid lateral interactions and enables lipid monolayers to serve as a basic platform for use with other investigative approaches. PMID:18214373

  1. On the effect of the solid support on the interleaflet distribution of lipids in supported lipid bilayers.

    PubMed

    Richter, Ralf P; Maury, Nicolas; Brisson, Alain R

    2005-01-01

    The adsorption and spreading of lipid vesicles on solid supports has become a popular way to create supported lipid bilayers (SLBs), but little attention has been paid to the possible redistribution of lipid material between the two leaflets of an SLB. We use the technique of quartz crystal microbalance with dissipation monitoring (QCM-D) to follow the adsorption of prothrombin on SLBs formed from sonicated unilamellar vesicles containing mixtures of dioleoylphosphatidylcholine (DOPC) and dioleoylphospatidylserine (DOPS). The specific interaction of prothrombin with negatively charged lipids is quantified and serves as a reporter of the content of accessible DOPS in SLBs. We compare results obtained on silica and mica and find that the underlying support can induce substantial redistribution of lipid material between the two leaflets. In particular, SLBs formed on mica showed a substantially depleted amount of accessible DOPS in the presence of calcium. The mechanisms that lead to the lipid redistribution process are discussed. PMID:15620318

  2. Lipid tubule growth by osmotic pressure

    NASA Astrophysics Data System (ADS)

    Rangamani, Padmini; Zhang, Di; Orster, George; Shen, Amy

    2013-11-01

    We present here a procedure for growing lipid tubules in vitro. This method allows us to grow tubules of consistent shape and structure and thus can be a useful tool for nano-engineering applications. There are three stages during the tubule growth process: initiation, elongation and termination. Balancing the forces that act on the tubule head shows that the growth of tubules during the elongation phase depends on the balance between osmotic pressure and the viscous drag exerted on the membrane from the substrate and the external fluid. Using a combination of mathematical modeling and experiment, we identify the key forces that control tubule growth during the elongation phase.

  3. Approaches toward functional fluid supported lipid bilayers

    NASA Astrophysics Data System (ADS)

    Weng, Kevin Chun-I.

    Planar supported lipid bilayers (PSLBs) have attracted immense interest for their properties as model cell membranes and for potential applications in biosensors and lab-on-a-chip devices. Our study covers three aspects of the construction, characterization, and application of functional PSLBs. First, a combination of micro-fabrication, the Langmuir-Blodgett (LB) technique, and fusion of extruded small unilamellar vesicle (E-SUVs) in sequence was used to create polymer-cushioned PSLBs in a microarray format. Random lipo-glycocopolymer mixed with L-alpha-phosphatidylcholine (egg PC) was compressed at the air-water interface and transferred onto the photoresist-patterned substrate by the LB technique to achieve spatially directed deposition. Construction of planar bilayers in an aqueous environment was subsequently completed by vesicle fusion. Epifluorescence microscopy, fluorescence recovery after photobleaching (FRAP), and electrophoresis-relaxation were employed to examine the resulting patterns as well as to verify the two-dimensional mobility of the supported membrane systems. This approach could possibly provide a useful route to create functional arrays of polymer-supported lipid bilayers. Second, we report the formation of fluid planar biomembranes on hydrophilic silica aerogels and xerogels. When the aerogel/xerogel was pre-hydrated and then allowed to incubate in egg PC E-SUV solution, lipid bilayers were formed due to the favorable interaction of vesicles with the hydroxyl-abundant silica surface. FRAP was used to determine the lateral diffusivity of membranes on aerogels. Quartz crystal microbalance with dissipation monitoring (QCM-D) was used to monitor the kinetics of the irreversible adsorption and fusion of vesicles into bilayers on xerogel thin films. Finally, we compared the formation of PSLBs with and without incorporation of monosialoganglioside GM1 (GM1) as the antigen for in situ antibody binding. Quantifiable differences were observed in the transformation of egg PC E-SUVs containing 0 mol%, 2 mol%, and 5 mol% GM1 to PSLBs by vesicle fusion on thermally evaporated silicon dioxide surfaces, as monitored by the QCM-D technique. FRAP was utilized to verify the retained, albeit reduced, fluidity of the GM1-containing PSLBs. Our analysis of rabbit serum antibodies binding to GM1 demonstrates this platform can be used to test for the presence of anti-lipid antibodies in serum.

  4. Lipid tubule growth by osmotic pressure

    PubMed Central

    Rangamani, Padmini; Zhang, Di; Oster, George; Shen, Amy Q.

    2013-01-01

    We present here a procedure for growing lipid tubules in vitro. This method allows us to grow tubules of consistent shape and structure, and thus can be a useful tool for nano-engineering applications. There are three stages during the tubule growth process: initiation, elongation and termination. Balancing the forces that act on the tubule head shows that the growth of tubules during the elongation phase depends on the balance between osmotic pressure and the viscous drag exerted on the membrane from the substrate and the external fluid. Using a combination of mathematical modelling and experiment, we identify the key forces that control tubule growth during the elongation phase. PMID:24004559

  5. 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.

  6. Lipid activators of protein kinase C

    SciTech Connect

    Chauhan, V.P.S.; Chauhan, A.; Deshmukh, D.S.; Brockerhoff, H. (New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY (USA))

    1990-01-01

    Among the many reported lipid activators of protein kinase C only those of high affinity can be considered true physiological effectors, at present the tumor promoters, e.g., phorbol esters; 1,2-diacyl-sn-glycerols; and phosphatidylinositol 4,5-bisphosphate. Many other compounds (including arachidonic acid) are activators at high, unphysiological concentrations only, and they seem to be sterically unsuited for bonding to the enzyme. Such pseudoactivators possibly act by scrambling the structure of the regulatory moiety of the kinase.

  7. Lipid membrane with low proton permeability.

    PubMed

    Biloti, Débora Nakai; Santana, Maria Helena Andrade; Pessine, Francisco Benedito Teixeira

    2003-04-01

    This work reports the production of a liposomal formulation, having a lipidic membrane with known chemical composition and a low proton permeability, as confirmed by physicochemical characterization of the maintenance of a transmembranic pH gradient. These liposomes consist of DSPC, DSPE-PEG, DSPG and cholesterol, with low internal pH. To verify the low proton permeability of these liposomal bilayers, a study of proton migration according to the fluorescence quenching of 9-aminoacridine (9AA), as well as CPT-11 encapsulation, were used to monitor the acidification of the intravesicular space. Both experiments showed that this liposomal formulation is able to maintain a transmembranic proton gradient. PMID:12659939

  8. Lipid composition in atheromatous plaque: evaluation of the lipid three-phase percentage

    Microsoft Academic Search

    Enrico Marinello; Carlo Setacci; Michele Giubbolini; Giuliano Cinci; Barbara Frosi; Brunetta Porcelli; Lucia Terzuoli

    2003-01-01

    There is a renewed interest in the study of plaque lipid composition because it is recognized that it, rather than the luminal narrowing, influences the plaque stability and determines patient symptoms.At this purpose, we quantitatively evaluated in the carotid plaque of different categories of patients the expression of triglycerides, phospholipids, cholesterol, free cholesterol, esters of cholesterol, and the percentages of

  9. LC/MS lipid profiling from human serum: a new method for global lipid extraction.

    PubMed

    Pellegrino, Roberto Maria; Di Veroli, Alessandra; Valeri, Aurora; Goracci, Laura; Cruciani, Gabriele

    2014-12-01

    Over the last decade, technological advances have improved the sensitivity and selectivity of LC/MS analyzers, providing very efficient tools for lipidomics research. In particular, the nine lipid classes that constitute 99 % of the human serum lipidome (sterols, cholesteryl esters, phosphocholines, phosphoethanolamines, sphingomyelins, triacylglycerols, fatty acids, lysophosphocholines, and diacylglycerols) can be easily detected. However, until today there has not been a unique technique for sample preparation that provides a satisfactory recovery for all of these nine classes together. In this work, we have developed and validated a new one-phase extraction (OPE) method that overcomes this limitation. This method was also compared with the gold standard lipid extraction methods such as Folch, Bligh & Dyer, and recently developed methods with methanol and methyl-tert-butyl ether. Results demonstrate that the mixture of methanol/chloroform/MTBE (MMC) provides a recovery very close to 100 % for all nine lipid classes of the human serum investigated. For this extraction method, 100 ?L of human serum is incubated with 2 mL of the solvents mixture, then vortexed and centrifuged. For its simplicity of execution, rapidity, reproducibility, and the reduced volume of sample required, this method opens the door to the use of human serum lipid profiling for large-scale applications in scientific research and clinical trials. PMID:25381612

  10. 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

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

    Microsoft Academic Search

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

    2007-01-01

    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

  12. Effect of Rowachol on biliary lipid secretion and serum lipids in normal volunteers.

    PubMed Central

    Leiss, O; von Bergmann, K

    1985-01-01

    The effect of Rowachol (200 mg tid), an essential oil preparation, on biliary lipid secretion and serum lipids was measured in six healthy male volunteers before and after four weeks of treatment. Biliary cholesterol and phospholipid secretion increased significantly from 113 +/- 36 (SD) mumol/h to 155 +/- 52 mumol/h (p less than 0.05) and from 409 +/- 145 mumol/h to 587 +/- 185 mumol/h (p less than 0.05), respectively. Bile acid secretion increased from 1519 +/- 662 mumol/h to 2287 +/- 1175 mumol/h (p greater than 0.05 and greater than 0.10). This marked increase in biliary lipid secretion was not followed by a change in molar composition of biliary lipids and lithogenicity of bile. Serum cholesterol and triglycerides declined from 4.9 mmol/l to 4.1 mmol/l (p less than 0.05) and from 1.2 mmol/l to 0.9 mmol/l (p less than 0.05) respectively. The ratio of high-density-lipoprotein cholesterol to total cholesterol increased from 0.22 to 0.31 (p less than 0.05). Although it has been shown previously that Rowachol could dissolve cholesterol gall stones the present results indicate that Rowachol alone has only weak litholytic properties, at least in normal volunteers, but might have several advantages when combined with chenodeoxycholic or ursodeoxycholic acid. PMID:3965364

  13. Cancer Cells Differentially Activate and Thrive on De Novo Lipid Synthesis Pathways in a Low-Lipid Environment

    PubMed Central

    Daniëls, Veerle W.; Smans, Karine; Royaux, Ines; Chypre, Melanie

    2014-01-01

    Increased lipogenesis is a hallmark of a wide variety of cancers and is under intense investigation as potential antineoplastic target. Although brisk lipogenesis is observed in the presence of exogenous lipids, evidence is mounting that these lipids may adversely affect the efficacy of inhibitors of lipogenic pathways. Therefore, to fully exploit the therapeutic potential of lipid synthesis inhibitors, a better understanding of the interrelationship between de novo lipid synthesis and exogenous lipids and their respective role in cancer cell proliferation and therapeutic response to lipogenesis inhibitors is of critical importance. Here, we show that the proliferation of various cancer cell lines (PC3M, HepG2, HOP62 and T24) is attenuated when cultured in lipid-reduced conditions in a cell line-dependent manner, with PC3M being the least affected. Interestingly, all cell lines - lipogenic (PC3M, HepG2, HOP62) as well as non-lipogenic (T24) - raised their lipogenic activity in these conditions, albeit to a different degree. Cells that attained the highest lipogenic activity under these conditions were best able to cope with lipid reduction in term of proliferative capacity. Supplementation of the medium with very low density lipoproteins, free fatty acids and cholesterol reversed this activation, indicating that the mere lack of lipids is sufficient to activate de novo lipogenesis in cancer cells. Consequently, cancer cells grown in lipid-reduced conditions became more dependent on de novo lipid synthesis pathways and were more sensitive to inhibitors of lipogenic pathways, like Soraphen A and Simvastatin. Collectively, these data indicate that limitation of access to exogenous lipids, as may occur in intact tumors, activates de novo lipogenesis is cancer cells, helps them to thrive under these conditions and makes them more vulnerable to lipogenesis inhibitors. These observations have important implications for the design of new antineoplastic strategies targeting the cancer cell's lipid metabolism. PMID:25215509

  14. Lipid changes in maturing oil-bearing plants. III. Changes in lipid classes in flax and safflower oils

    Microsoft Academic Search

    Mary E. McKillican; R. P. A. Sims

    1963-01-01

    Seeds from Raja flax and Indian safflower were collected at increasing stages of maturity and the free lipid extracted from\\u000a them with hexane. The true lipid material obtained in this manner was separated into lipid classes by silicic acid column\\u000a chromatography using a diethyl ether-hexane gradient and methanol for the phospholipids. Thin-layer chromatography was used\\u000a to establish the homogeneity of

  15. In-plane homogeneity and lipid dynamics in tethered bilayer lipid membranes (tBLMs)

    PubMed Central

    Shenoy, Siddharth; Moldovan, Radu; Fitzpatrick, James; Vanderah, David J.; Deserno, Markus; Lösche, Mathias

    2011-01-01

    Tethered bilayer lipid membranes (tBLMs) were prepared by the self-assembly of thiolated lipidic anchor molecules on gold, followed by phospholipid precipitation via rapid solvent exchange. They were characterized by their in-plane structure, dynamics and dielectric properties. We find that the in-plane homogeneity and resistivity of the tBLMs depend critically on a well-controlled sample environment during the rapid solvent-exchange procedure. The in-plane dynamics of the systems, assessed by fluorescence correlation spectroscopy (FCS) as the diffusivity of free, labeled phospholipid dissolved in the membrane, depend on the density of the lipidic anchors in the bilayer leaflet proximal to the substrate as well as on details of the molecular structure of the anchor lipid. In DOPC tBLMs in which tethers are laterally dilute (sparsely tethered bilayer lipid membranes, stBLMs), measured diffusivities, D ? 4 ?m2 s?1, are only slightly greater than those reported in physisorbed bilayers (M. Przybylo, J. Sykora, J. Humpolíckova, A. Benda, A. Zan and M. Hof, Langmuir, 2006, 22, 9096–9099). However, when we distinguish label diffusion in the proximal and in the distal bilayer leaflets, we observe distinct diffusivities, D ? 2 ?m2 s?1 and 7 ?m2 s?1, respectively. The value observed in the distal leaflet is identical to that in free membranes. stBLMs completed with phytanoyl lipids (DPhyPC) show consistently lower label diffusivity than those completed with unsaturated chains (DOPC). As the length of the tether chain increases, a reduction in the apparent diffusivity is observed, which we interpret as an increased propensity of the proximal bilayer leaflet to host free lipid. We also investigated preparation conditions that control whether the tBLMs are laterally homogeneous, as assessed by optical microscopy. In laterally heterogeneous bilayers, the label diffusivity varies only by a factor of ~2 to 4, indicating that the regions in the bilayers with different label solubilities do not correspond to distinct phases, such as a fluid phase coexisting with a gel phase. PMID:21572933

  16. 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

  17. Lipid profiling by electrospray ionization tandem mass spectrometry and the identification of lipid phosphorylation by kinases in potato stolons

    PubMed Central

    Cenzano, Ana M.; Cantoro, Renata; Teresa Hernandez-Sotomayor, S. M.; Abdala, Guillermina I.; Racagni, Graciela E.

    2013-01-01

    There is limited information about the involvement of lipids and esterified fatty acids in signaling pathways during plant development. The purpose of this study was to evaluate the lipid composition and molecular species of potato (Solanum tuberosum L., cv. Spunta) stolons and to identify phosphorylated lipids in the first two developmental stages of tuber formation. Lipid profiling was determined using ESI-MS/MS, a useful method for the determination of the biosynthesis and catabolism of lipids based on their fatty acid composition. The most prevalent compound identified in this study was phosphatidic acid (PA); digalactosyldiacylglycerol (DGDG) was the second most abundant compound. A 34:2 species was identified in PA, phosphatidylcholine (PC), phosphatidylinositol (PI), and phosphatidylethanolamine (PE). The identification of lipid phosphorylation by kinases was revealed by the presence of the phosphorylated lipids. PA was metabolized to diacylglycerol pyrophosphate (DGPP) by phosphatidic acid kinase (PAK). This work establishes a correlation between lipid fatty acid composition and lipid metabolism enzymes at the beginning of tuber formation and is the first report of PAK activity in the early events of potato tuber formation. PMID:22142228

  18. Production of lipids in 10 strains of Chlorella and Parachlorella, and enhanced lipid productivity in Chlorella vulgaris.

    PubMed

    P?ibyl, Pavel; Cepák, Vladislav; Zachleder, Vilém

    2012-04-01

    We tested 10 different Chlorella and Parachlorella strains under lipid induction growth conditions in autotrophic laboratory cultures. Between tested strains, substantial differences in both biomass and lipid productivity as well as in the final content of lipids were found. The most productive strain (Chlorella vulgaris CCALA 256) was subsequently studied in detail. The availability of nitrates and/or phosphates strongly influenced growth and accumulation of lipids in cells by affecting cell division. Nutrient limitation substantially enhanced lipid productivity up to a maximal value of 1.5 g?l(-1) day(-1). We also demonstrated the production of lipids through large-scale cultivation of C. vulgaris in a thin layer photobioreactor, even under suboptimal conditions. After 8 days of cultivation, maximal lipid productivity was 0.33 g?l(-1) day(-1), biomass density was 5.7 g?l(-1) dry weight and total lipid content was more than 30% dry weight. C. vulgaris lipids comprise fatty acids with a relatively high degree of saturation compared with canola oil offering a possible alternative to the use of higher plant oils. PMID:22361856

  19. Lipid Parameters – Significance in Patients with Endogenous Depression

    PubMed Central

    Kale, Anita B.; Kale, Sunil B.; Chalak, Shivaji S.; S.R., Tankhiwale; Bang, G.; Agrawal, Mohit; Kaple, Meghali

    2014-01-01

    Background: People are aware of the consequences of high serum lipid levels, specifically, total cholesterol. Awareness about harmful effects of very low levels of serum lipids is still lacking. Very low levels of serum lipids lead to psychological consequences. Objectives: The objective of this study was to show whether there was a significant relationship between serum lipid levels and depression. Material and Methods: Total 70 subjects were included in this study. 40 subjects suffering from depression as assessed with the help of clinical findings and Beck Depression Inventory (BDI) scores were included in the study group, while control group comprised of 30 normal subjects. Lipid profile was done on blood samples obtained after overnight fasting. BDI scores were also obtained in control group using BDI. Co-relation between BDI score and lipid levels was obtained in both the groups. Results: Serum lipid levels were significantly low in study group as compared to control group. There was a significant negative co-relationship between serum lipid levels with depression. Subjects of study group having lower lipid levels specifically Total Cholestrol (TC) (r = -0.78), Low-Density Lipoprotein (LDL) (r = -0.69), TG (r = -0.41) and Very Low-Density Lipoprotein (VLDL)(r = - 0.418), showed higher BDI scores (p<0.05). Conclusion: We can conclude that there is a significant relationship between low TC and depression. Similarly, low levels of serum LDL, TG and VLDL also showed significant relationship with depression. Lipid levels below a certain limit are not good as it may cause depression. Patients with low lipid levels should be screened for depression so that if necessary, corrective measures can be taken at the earliest. PMID:24596713

  20. Lipid ion channels and the role of proteins.

    PubMed

    Mosgaard, Lars D; Heimburg, Thomas

    2013-12-17

    In the absence of proteins, synthetic lipid membranes can display quantized conduction events for ions that are virtually indistinguishable from those of protein channels. The phenomenological similarities between typical conductances are striking: they are of equal order and show similar lifetime distributions and current histograms. They can include conduction bursts, flickering, and multistep conductance. Lipid channels can be gated by voltage and blocked by drugs. They respond to changes in lateral membrane tension and temperature. Thus, they behave like voltage-gated, temperature-gated, and mechano-sensitive protein channels, or like receptors. The similarity between lipid and protein channels poses an important problem for the interpretation of protein channel data. For example, the Hodgkin-Huxley theory for nerve pulse conduction requires a selective mechanism for the conduction of sodium and potassium ions. To this end, the lipid membrane must act both as a capacitor and as an insulator. Nonselective ion conductance by mechanisms other than the gated protein channels challenges the proposed mechanism for pulse propagation. Nevertheless, textbooks rarely describe the properties of the lipid membrane surrounding the proteins in their discussions of membrane models. These similarities lead to important questions: Do these similarities in lipid and protein channels result from a common mechanism, or are these similarities fortuitous? What distinguishes protein channels from lipid channels, if anything? In this Account, we document experimental and theoretical findings that show the similarity between lipid and protein channels. We discuss important cases where protein channel function strongly correlates with the properties of the lipid. Based on statistical thermodynamics simulations, we discuss how such correlations could come about. We suggest that proteins can act as catalysts for lipid channel formation and that this hypothesis can explain some of the unexplained correlations between protein and lipid membrane function. PMID:23902303

  1. 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.

  2. Structural analysis of DNA complexation with cationic lipids

    PubMed Central

    Marty, Regis; N'soukpoé-Kossi, Christophe N.; Charbonneau, David; Weinert, Carl Maximilian; Kreplak, Laurent; Tajmir-Riahi, Heidar-Ali

    2009-01-01

    Complexes of cationic liposomes with DNA are promising tools to deliver genetic information into cells for gene therapy and vaccines. Electrostatic interaction is thought to be the major force in lipid–DNA interaction, while lipid-base binding and the stability of cationic lipid–DNA complexes have been the subject of more debate in recent years. The aim of this study was to examine the complexation of calf-thymus DNA with cholesterol (Chol), 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), dioctadecyldimethylammoniumbromide (DDAB) and dioleoylphosphatidylethanolamine (DOPE), at physiological condition, using constant DNA concentration and various lipid contents. Fourier transform infrared (FTIR), UV-visible, circular dichroism spectroscopic methods and atomic force microscopy were used to analyse lipid-binding site, the binding constant and the effects of lipid interaction on DNA stability and conformation. Structural analysis showed a strong lipid–DNA interaction via major and minor grooves and the backbone phosphate group with overall binding constants of KChol = 1.4 (±0.5) × 104 M?1, KDDAB = 2.4 (±0.80) × 104 M?1, KDOTAP = 3.1 (±0.90) × 104 M?1 and KDOPE = 1.45 (± 0.60) × 104 M?1. The order of stability of lipid–DNA complexation is DOTAP>DDAB>DOPE>Chol. Hydrophobic interactions between lipid aliphatic tails and DNA were observed. Chol and DOPE induced a partial B to A-DNA conformational transition, while a partial B to C-DNA alteration occurred for DDAB and DOTAP at high lipid concentrations. DNA aggregation was observed at high lipid content. PMID:19103664

  3. Physicochemical Investigations on Solid Lipid Nanoparticles and on Oil-Loaded Solid Lipid Nanoparticles: A Nuclear Magnetic Resonance and Electron Spin Resonance Study

    Microsoft Academic Search

    Katja Jores; Wolfgang Mehnert; Karsten Mäder

    2003-01-01

    Purpose. Recently, colloidal dispersions made of mixtures from solid and liquid lipids have been described to combine controlled-release characteristics with higher drug-loading capacities than solid lipid nanoparticles (SLNs). It has been proposed that these nanostructured lipid carriers (NLCs) are composed of oily droplets that are embedded in a solid lipid matrix. The present work investigates the structure and performance of

  4. The potential role of sigma-1 receptors in lipid transport and lipid raft reconstitution in the brain: Implication for drug abuse

    Microsoft Academic Search

    Teruo Hayashi; Tsung-Ping Su

    2005-01-01

    The brain is highly enriched in lipids. However, the molecular biological roles of lipids in the brain have been largely unexplored. Although, in 1990s, several studies have demonstrated the roles of lipids in a variety of neuronal functions and certain neurological diseases, the involvement of lipids in drug dependence, if any, is almost totally unknown. Sigma-1 receptors are brain-enriched proteins

  5. Clinical Trial: Marine Lipid Suppositories as Laxatives

    PubMed Central

    Ormarsson, Orri Thor; Geirsson, Thormodur; Bjornsson, Einar Stefan; Jonsson, Tomas; Moller, Pall; Loftsson, Thorsteinn; Stefansson, Einar

    2012-01-01

    Cod-liver oil and other marine products containing polyunsaturated fatty acids have anti-inflammatory, anti-bacterial and anti-viral effects and may be useful in the treatment of various inflammatory and infectious diseases. We developed suppositories and ointment with 30% free fatty acid (FFA) extract from omega-3 fish oil. Our purpose was to evaluate the safety of marine lipid suppositories and ointment in healthy volunteers and to explore the laxative effect of the suppositories. Thirty healthy volunteers were randomized either to a study group administrating 30% FFA suppositories and applying 30% FFA ointment to the perianal region twice per day for two weeks, or to a control group using placebo suppositories and ointment in a double blinded manner. Results: No serious toxic effects or irritation were observed. In the study group 93% felt the urge to defecate after administration of the suppositories as compared to 37% in the control group (P = 0.001). Subsequently 90% in the study group defecated, compared to 33% in the control group (P = 0.001). Conclusion: The marine lipid suppositories and ointment were well tolerated with no significant toxic side effects observed during the study period. The suppositories have a distinct laxative effect and we aim to explore this effect in further clinical trials. PMID:23118720

  6. Triacylglycerol hydrolase: role in intracellular lipid metabolism.

    PubMed

    Dolinsky, V W; Gilham, D; Alam, M; Vance, D E; Lehner, R

    2004-07-01

    Recent scientific advances have revealed the identity of several enzymes involved in the synthesis, storage and catabolism of intracellular neutral lipid storage droplets. An enzyme that hydrolyzes stored triacylglycerol (TG), triacylglycerol hydrolase (TGH), was purified from porcine, human and murine liver microsomes. In rodents, TGH is highly expressed in liver as well as heart, kidney, small intestine and adipose tissues, while in humans TGH is mainly expressed in the liver, adipose and small intestine. TGH localizes to the endoplasmic reticulum and lipid droplets. The TGH genes are located within a cluster of carboxylesterase genes on human and mouse chromosomes 16 and 8, respectively. TGH hydrolyzes stored TG, and in the liver, the lipolytic products are made available for VLDL-TG synthesis. Inhibition of TGH activity also inhibits TG and apolipoprotein B secretion by primary hepatocytes. A role for TGH in basal TG lipolysis in adipocytes has been proposed. TGH expression and activity is both developmentally and hormonally regulated. A model for the function of TGH is presented and discussed with respect to tissue specific functions. PMID:15224187

  7. Effect of chloroquine on intestinal lipid metabolism

    SciTech Connect

    Mansbach, C.M. 2d.; Arnold, A.; Garrett, M.

    1987-11-01

    Most studies that have quantitated recovery of infused lipid in the intestinal mucosa and mesenteric lymph have only been able to recapture 50-75%. One possibility is that the missing lipid enters a triacylglycerol (TG) storage pool in the enterocyte and is hydrolyzed by lysosomal lipase, and the free fatty acid released is transported by the portal vein. This postulate was tested by comparing glyceryl trioleate (TO)-infused rats pretreated with the lysosomotropic drug, chloroquine (6.3 mg.kg-1.h-1) with saline controls. Chloroquine increased mucosal TG from 94 +/- 6 to 128 +/- 8 mumol. Additionally, the specific activity of the mucosal TG relative to the infused (/sup 3/H)TO was reduced in the treated rats. The mucosal TG increase was not due to impaired TG output, which remained the same as controls. We conclude that the TG in the acid lipase-sensitive pool derives most of its glyceride-glycerol from endogenous sources. Furthermore, the increment in mucosal TG caused by chloroquine is not enough to explain the majority of the acyl groups unaccounted for in the mucosa and lymph after a TG infusion. For these a direct passage of acyl groups through the enterocyte is postulated.

  8. Lipids of the pawpaw fruit: Asimina triloba.

    PubMed

    Wood, R; Peterson, S

    1999-10-01

    The fatty acid composition and structure of pawpaw fruit (Asimina triloba) triglycerides were examined and found to contain fatty acids ranging from C6 to C20. Octanoate represented 20% of the fatty acids while other medium-chain fatty acids were present in low amounts. Analysis of the intact triglycerides by high-temperature gas-liquid chromatography gave an unusual three-cycle carbon number distribution. Analysis of triglyceride fractions separated according to degree of unsaturation suggested that one octanoate was paired with diglyceride species containing long-chain fatty acids. Determination of the double-bond positions of monoene fatty acids revealed cis delta9 and cis delta11 hexadecenoate and cis delta9, cis delta11, and cis delta13 octadecenoate isomers were present in significant quantities. Octanoate and positional monoene fatty acid isomers were found only in the fruit lipids and not in the seed lipids. Phenacyl esters of fatty acids were found to be useful derivatives for structure determination using multiple types of analyses. PMID:10580337

  9. Lipid-lowering therapy in older persons

    PubMed Central

    2015-01-01

    Numerous randomized, double-blind, placebo-controlled studies and observational studies have shown that statins reduce mortality and major cardiovascular events in older high-risk persons with hypercholesterolemia. The Heart Protection Study showed that statins reduced mortality and major cardiovascular events in high-risk persons regardless of the initial level of serum lipids, age, or gender. The updated National Cholesterol Education Program III guidelines state that in very high-risk persons, a serum low-density lipoprotein (LDL) cholesterol level of < 70 mg/dl (1.8 mmol/l) is a reasonable clinical strategy for moderately high-risk persons (2 or more risk factors and a 10-year risk for coronary artery disease of 10% to 20%), and the serum LDL cholesterol should be reduced to < 100 mg/dl (2.6 mmol/l). When LDL cholesterol-lowering drug therapy is used to treat high-risk persons or moderately high-risk persons, the serum LDL cholesterol should be reduced by at least 30% to 40%. The serum LDL cholesterol should be decreased to less than 160 mg/dl in persons at low risk for cardiovascular disease. Addition of other lipid-lowering drugs to statin therapy has not been demonstrated to further reduce cardiovascular events and mortality. PMID:25861289

  10. Imaging Molecular Transport across Lipid Bilayers

    PubMed Central

    Li, Su; Hu, Peichi C.; Malmstadt, Noah

    2011-01-01

    Low-molecular-weight carboxylic acids have many properties common to small molecule drugs. The transport of these acids across cell membranes has been widely studied, but these studies have produced wildly varying permeability values. Recent reports have even claimed that the transport behavior of these drugs is contrary to the rule of thumb called Overton's rule, which holds that more lipophilic molecules transport across lipid membranes more quickly. We used confocal microscopy to image the transport of carboxylic acids with different lipophilicities into a giant unilamellar lipid vesicle (GUV). Fluorescein-dextran, which acts as a pH-sensitive dye, was encapsulated in the GUV to trace the transport of acid. The GUV was immobilized on the surface of a microfluidic channel by biotin-avidin binding. This microchannel allows the rapid and uniform exchange of the solution surrounding the GUV. Using a spinning-disk confocal microscope, the entire concentration field is captured in a short (<100 ms) exposure. Results show that more lipophilic acids cross the bilayer more quickly. A finite difference model was developed to simulate the experimental process and derive permeabilities. The permeabilities change with the same trend as literature oil-water partition coefficients, demonstrating that Overton's rule applies to this class of molecules. PMID:21806938

  11. Heat stability of prion rods and recombinant prion protein in water, lipid and lipid-water mixtures.

    PubMed

    Appel, T; Wolff, M; von Rheinbaben, F; Heinzel, M; Riesner, D

    2001-02-01

    Prion rods, i.e. insoluble infectious aggregates of the N-terminally truncated form of the prion protein, PrP 27-30, and the corresponding recombinant protein, rPrP(90-231), were autoclaved in water, bovine lipid or lipid-water mixtures for 20 min at temperatures from 100 to 170 degrees C. A protocol was developed for the quantitative precipitation of small amounts of protein from large excesses of lipid. PrP remaining undegraded after autoclaving was quantified by Western blot and degradation factors were calculated. The Arrhenius plot of the rate of degradation vs temperature yielded linear relationships for prion rods in water or lipid-water as well as for rPrP(90-231) in lipid-water. The presence of lipids increased the heat stability of prion rods, especially at lower temperatures. Prion rods had a much higher thermal stability compared to rPrP. Autoclaving of prion rods in pure lipid gave different results - not simple degradation but bands indicative of covalently linked dimers, tetramers and higher aggregates. The heat stability of prion rods in pure lipid exceeded that in lipid-water mixtures. Degradation factors larger than 10(4) were reached at 170 degrees C in the presence of lipids and at 150 degrees C in the absence of lipids. The linear correlation of the data allows cautious extrapolation to conditions not tested, i.e. temperatures higher than 170 degrees C. A factual basis for assessing the biological safety of industrial processes utilizing potentially BSE-or scrapie-contaminated animal fat is provided. PMID:11161287

  12. Anaerobic biodegradation of lipids of the marine microalga Nannochloropsis salina

    Microsoft Academic Search

    Vincent Grossi; Peter Blokker; Jaap S Sinninghe Damsté

    2001-01-01

    In order to determine the susceptibility to anaerobic biodegradation of the different lipid biomarkers present in a marine microalga containing algaenan, portions of one large batch of cultured Nannochloropsis salina (Eustigmatophyceae) were incubated in anoxic sediment slurries for various times. After 442 days, all lipids studied [mono-, di-, and tri-unsaturated hydrocarbons, long-chain unsaturated alcohols and alkyl diols, phytol, sterols, saturated

  13. Secondary metabolites and lipids in Chara globularis Thuill

    Microsoft Academic Search

    Vassya Bankova; Kamen Stefanov; St. Dimitrova-Konaklieva; Gergana Keremedchieva; Xavie Frette; Christina Nikolova; Atanas Kujumgiev; Simeon Popov

    2001-01-01

    Sterols, volatiles and lipid fatty acids were analysed in the fresh-water alga Chara globularis. Five sterols, two of them new for the genus, were identified, together with 12 fatty acids from lipids. The volatiles appeared to form a complex mixture, containing mainly acids (part of them chlorinated), terpenoids, ketones, hydrocarbons, etc. No flavonoids have been found. Antibacterial activity of extracts

  14. 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

  15. 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...

  16. Lipid Mesophase Organization and Single Ionic Channel Phenomenon

    Microsoft Academic Search

    A. E. Sokolova; A. E. Grinfeldt; A. A. Lev; Yu. M. Lvov

    1990-01-01

    A correlation between organization of lipid mesophases and single channel phenomenon was investigated by a comparison of small angle X-ray diffraction data and recording of current fluctuations in the bilayers formed from correspondent lipid systems. Transition from lamellar (L?) to hexagonal (HII) phase in the presence of classical channel forming compound - gramicidin A had been proved. It was found

  17. Bioadhesive giant vesicles for monitoring hydroperoxidation in lipid membranes.

    PubMed

    Aoki, P H B; Schroder, A P; Constantino, C J L; Marques, C M

    2015-08-14

    Osmotic stresses, protein insertion or lipid oxidation lead to area increase of self-assembled lipid membranes. However, methods to measure membrane expansion are scarce. Challenged by recent progress on the control of phospholipid hydroperoxidation, we introduce a method to quantitatively evaluate membrane area increase based on the bio-adhesion of Giant Unilamellar Vesicles. PMID:26067909

  18. Interactions of lipids with aquaporin-0 and other membrane proteins.

    PubMed

    Hite, Richard K; Gonen, Tamir; Harrison, Stephen C; Walz, Thomas

    2008-07-01

    The structure of aquaporin-0 (AQP0) has recently been determined by electron crystallography of two-dimensional (2D) crystals and by X-ray crystallography of three-dimensional (3D) crystals. The electron crystallographic structure revealed nine lipids per AQP0 monomer, which form an almost complete bilayer. The lipids adopt a wide variety of conformations and tightly fill the space between adjacent AQP0 tetramers. The conformations of the lipid acyl chains appear to be determined not only by the protein surface but also by the acyl chains of adjacent lipid molecules. In the X-ray structure, the hydrophobic region of the protein is surrounded by a detergent micelle, with two ordered detergent molecules per AQP0 monomer. Despite the different environments, the electron crystallographic and X-ray structures of AQP0 are virtually identical, but they differ in the temperature factors of the atoms that either contact the lipids in the 2D crystals or are exposed to detergents in the 3D crystals. The temperature factors are higher in the X-ray structure, suggesting that the detergent-exposed AQP0 residues are less ordered than the corresponding ones contacting lipids in the 2D crystals. An examination of ordered detergent molecules in crystal structures of other aquaporins and of lipid molecules in 2D and 3D crystals of bacteriorhodopsin suggests that the increased conformational variability of detergent-exposed residues compared to lipid-contacting residues is a general feature. PMID:17932686

  19. Effect of Sodium Chloride on a Lipid Bilayer

    Microsoft Academic Search

    Rainer A. Böckmann; Agnieszka Hac; Thomas Heimburg; Helmut Grubmüller

    2003-01-01

    Electrostatic interactions govern structural and dynamical properties of membranes and can vary considerably with the composition of the aqueous buffer. We studied the influence of sodium chloride on a pure POPC lipid bilayer by fluorescence correlation spectroscopy experiments and molecular dynamics simulations. Increasing sodium chloride concentration was found to decrease the self-diffusion of POPC lipids within the bilayer. Self-diffusion coefficients

  20. SEASONAL FRUIT PREFERENCES FOR LIPIDS AND SUGARS BY AMERICAN ROBINS

    Microsoft Academic Search

    Christopher A. Lepczyk; K. Greg Murray; Kathy Winnett-Murray; Paul Bartell; Eric Geyer; Timothy Work

    2000-01-01

    Fruit preference by birds is a complex process based upon the morphology and spatial arrangement of fruits and on the physiological needs and capabilities of birds. In North America, most fruits can be divided into two groups based on nutritional content: those rich in sugars relative to lipids, and those rich in lipids relative to sugars. To investigate how fruit

  1. Postprandial Lipids in Blood Plasma of Preruminant Calves

    Microsoft Academic Search

    D. Bauchart; B. Aurousseau

    1981-01-01

    Four 3-wk-old calves were fed twice a day a milk replacer containing 21% tallow. Lipids in blood plasma were studied for 7 h after the morning meal. Fatty acid concentration in each class of lipids was determined by internal stan- dard procedure. Results were homogenous among animals. Postprandial time had a highly significant effect on both qualitative and quantitative aspects

  2. Current Status of Acrolein as a Lipid Peroxidation Product

    Microsoft Academic Search

    Koji Uchida

    1999-01-01

    There is increasing evidence that aldehydes generated endogenously during lipid peroxidation contribute to the pathophysiologic effects associated with oxidative stress in cells and tissues. A number of reactive lipid aldehydes, such as 4-hydroxy-2-alkenals and malondialdehyde, have been implicated as causative agents in cytotoxic processes initiated by the exposure of biologic systems to oxidizing agents. Recently, acrolein (CH2 = CH ?

  3. 40th anniversary of bilayer lipid membrane (BLM) research

    NASA Astrophysics Data System (ADS)

    Ottova, Angelica L.; Tien, H. Ti

    2001-09-01

    At the Symposium on the Plasma Membrane in 1961, when a group of unknown researchers reported the reconstitution of a bimolecular lipid membrane in vitro, the report was met with scepticism. Those present included some of the foremost proponents of the lipid bilayer concept, such as Davson, Danielli, Stoechenius, Adrian, Mauro, Finean, and many others.

  4. Lipid hydroperoxide generation, turnover, and effector action in biological systems

    Microsoft Academic Search

    Albert W. Girotti

    Lipid peroxidation is a well known example of oxidative damage in cell membranes, lipoproteins, and other lipid-containing structures. Peroxidative modification of unsaturated phospholipids, glycolipids, and cholesterol can occur in reactions triggered by i ) free radical species such as oxyl radicals, peroxyl radicals, and hydroxyl radicals derived from iron-mediated reduction of hydrogen perox- ide or ii ) non-radical species such

  5. 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

  6. Characterization of lipid oxidation products in quinoa ( Chenopodium quinoa)

    Microsoft Academic Search

    Su-Chuen Ng; Alfred Anderson; Janice Coker; Martin Ondrus

    2007-01-01

    The oxidative stability of lipids in processed quinoa was investigated in this study. Ground quinoa was subjected to accelerated aging for 30 days at 25, 35, 45, and 55°C. Three samples were removed from each temperature treatment every 3 days. Free fatty acids, conjugated diene hydroperoxides, and hexanal were used as indicators of lipid oxidation. Storage time and temperature had

  7. Lipid A Modification Systems in Gram-Negative

    E-print Network

    Bishop, Russell

    Lipid A Modification Systems in Gram-Negative Bacteria Christian R.H. Raetz,1 C. Michael Reynolds,1 gram-negative bacteria. Escherichia coli lipid A is synthesized on the cytoplasmic surface of the inner not required for growth, the modification en- zymes modulate virulence of some gram-negative pathogens. Het

  8. Oleuropein on lipid and fatty acid composition of rat heart

    Microsoft Academic Search

    Valentina Ruíz-Gutiérrez; Francisco J. G. Muriana; Roberto Maestro; Enrique Graciani

    1995-01-01

    Male rats of the Wistar strain were given oleuropein for 3 weeks at a dose of 25 or 50 mg\\/kg of body weight. Heart samples were analyzed for the lipid composition by the Iatroscan TLCFID technique and for the fatty acid profile of neutral and polar lipids by the capillary gas chromatography. In addition, the oleuropein, ?- and ?-tocopherol content

  9. Role of Physical Structures in Bulk Oils on Lipid Oxidation

    Microsoft Academic Search

    Wilailuk Chaiyasit; Ryan J. Elias; D. Julian McClements; Eric A. Decker

    2007-01-01

    Lipid oxidation is important to food manufacturers especially when they increase unsaturated lipids in their products to improve nutritional profiles. Unfortunately, the number of antioxidants available to food manufacturers to control oxidative rancidity is limited and the approval of new antioxidants is unlikely due to economic barriers in obtaining government approval for new food additives. Therefore, new antioxidant technologies are

  10. Fatty acid methyl ester profiles of bat wing surface lipids.

    PubMed

    Pannkuk, Evan L; Fuller, Nathan W; Moore, Patrick R; Gilmore, David F; Savary, Brett J; Risch, Thomas S

    2014-11-01

    Sebocytes are specialized epithelial cells that rupture to secrete sebaceous lipids (sebum) across the mammalian integument. Sebum protects the integument from UV radiation, and maintains host microbial communities among other functions. Native glandular sebum is composed primarily of triacylglycerides (TAG) and wax esters (WE). Upon secretion (mature sebum), these lipids combine with minor cellular membrane components comprising total surface lipids. TAG and WE are further cleaved to smaller molecules through oxidation or host enzymatic digestion, resulting in a complex mixture of glycerolipids (e.g., TAG), sterols, unesterified fatty acids (FFA), WE, cholesteryl esters, and squalene comprising surface lipid. We are interested if fatty acid methyl ester (FAME) profiling of bat surface lipid could predict species specificity to the cutaneous fungal disease, white nose syndrome (WNS). We collected sebaceous secretions from 13 bat spp. using Sebutape(®) and converted them to FAME with an acid catalyzed transesterification. We found that Sebutape(®) adhesive patches removed ~6× more total lipid than Sebutape(®) indicator strips. Juvenile eastern red bats (Lasiurus borealis) had significantly higher 18:1 than adults, but 14:0, 16:1, and 20:0 were higher in adults. FAME profiles among several bat species were similar. We concluded that bat surface lipid FAME profiling does not provide a robust model predicting species susceptibility to WNS. However, these results provide baseline data that can be used for lipid roles in future ecological studies, such as life history, diet, or migration. PMID:25227993

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

    Microsoft Academic Search

    Michael J. Anteau; Alan D. Afton; Bradley Steven Launikonis

    2011-01-01

    Animals frequently undergo periods when they accumulate lipid reserves for subsequent energetically expensive activities, such as migration or breeding. During such periods, daily lipid-reserve dynamics (DLD) of sentinel species can quantify how landscape modifications affect function, health, and resilience of ecosystems. Aythya affinis (Eyton 1838; lesser scaup; diving duck) are macroinvertebrate predators; they migrate through an agriculturally dominated landscape in

  12. The influence of nonpolar lipids on tear film dynamics

    NASA Astrophysics Data System (ADS)

    Breward, Chris

    2013-11-01

    We will examine the effects of the presence of nonpolar lipids on the evolution of a tear film during a blink. We will track the thickness of the aqueous tear layer, the thickness of the nonpolar lipid layer, and the concentration of the polar lipids that reside between the two. Our model can be reduced in various limits to previous models for tear dynamics studied. We present numerical solutions for the evolution of the tear film and show how the key parameters play a role in determining how the nonpolar lipid spreads. We will examine the effects of the presence of nonpolar lipids on the evolution of a tear film during a blink. We will track the thickness of the aqueous tear layer, the thickness of the nonpolar lipid layer, and the concentration of the polar lipids that reside between the two. Our model can be reduced in various limits to previous models for tear dynamics studied. We present numerical solutions for the evolution of the tear film and show how the key parameters play a role in determining how the nonpolar lipid spreads. This work was partially supported by Award No. KUK-C1-013-04 made by King Abdullah University of Science and Technology (KAUST).

  13. Lipid peroxidation and hepatic antioxidants in alcoholic liver disease.

    PubMed Central

    Situnayake, R D; Crump, B J; Thurnham, D I; Davies, J A; Gearty, J; Davis, M

    1990-01-01

    The generation of hepatic liver peroxidation by free radicals has been proposed as a mechanism for ethanol induced hepatotoxicity. To investigate this hypothesis, lipid extracts from hepatic needle biopsy specimens from alcoholic subjects were examined for evidence of lipid peroxidation by measuring total conjugated dienes by derivative spectroscopy and, after hydrolysis of hepatic lipid extract and reverse phase high performance liquid chromatography, the molar ratio between a diene-conjugated linoleic acid isomer (18:2 (9,11)) and the parent linoleic acid isomer (18:2(9,12)). Changes were related to hepatic histology, iron deposition, glutathione and vitamin E values. Derivative spectroscopy minima suggestive of diene conjugation were identified at 233 and 242 nm and correlated weakly, suggesting these two minima may represent different classes of lipid dienes. There was a weak relation with inflammatory histological changes in the biopsy specimen but no correlation with hepatic iron grade, glutathione, or vitamin E lipid ratio. The proportion of 18:2(9,11) linoleic acid in hepatic lipids correlated significantly with inflammatory histological features and inversely with hepatic glutathione. Furthermore, hepatic glutathione was lower in biopsy specimens with greater iron staining. The ratio of vitamin E to lipid was not related to histological group, inflammation, or iron grade. These findings suggest that excess alcohol consumption leads to hepatic inflammation and lipid peroxidation. PMID:2253918

  14. Lipid Raft Proteomics: More than Just Detergent-Resistant Membranes

    Microsoft Academic Search

    Leonard J. Foster; Queenie W. T. Chan

    The fluid mosaic model of membrane bilayers implies that proteins and lipids are homoge- nously distributed in the 2D surface of a membrane. Numerous lines of biochemical, biophysical and optical evidence now suggest that organized sub-domains of membranes exist, a subset of which are known as lipid rafts. Rafts are enriched in cholesterol, satu- rated phospholipids, sphingolipids and what is

  15. Original article Effect of dietary levels of lipid and carbohydrate

    E-print Network

    Paris-Sud XI, Université de

    Original article Effect of dietary levels of lipid and carbohydrate on growth performance, body of digestible carbohydrate and the highest plasma glucose level was attained later at 8°C in comparison to 18°C. trout / carbohydrate/lipid ratio / growth performance / glycaemia / temperature Résumé ― Effets

  16. Formation and Functions of the Corneocyte Lipid Envelope (CLE)?

    PubMed Central

    Elias, Peter M.; Gruber, Robert; Crumrine, Debra; Menon, Gopinathan; Williams, Mary L; Wakefield, Joan S.; Holleran, Walter M.; Uchida, Yoshikazu

    2013-01-01

    Corneocytes in mammalian stratum corneum are surrounded by a monolayer of covalently bound ?-OH-ceramides that form the corneocyte (-bound) lipid envelope (CLE). We review here the structure, composition, and possible functions of this structure, with insights provided by inherited and acquired disorders of lipid metabolism. PMID:24076475

  17. Nuclear Receptors and Lipid Physiology: Opening the X-Files

    Microsoft Academic Search

    Ajay Chawla; Joyce J. Repa; Ronald M. Evans; David J. Mangelsdorf

    2001-01-01

    Cholesterol, fatty acids, fat-soluble vitamins, and other lipids present in our diets are not only nutritionally important but serve as precursors for ligands that bind to receptors in the nucleus. To become biologically active, these lipids must first be absorbed by the intestine and transformed by metabolic enzymes before they are delivered to their sites of action in the body.

  18. Antioxidant Activity of Solid Lipid Nanoparticles Loaded with Umbelliferone

    Microsoft Academic Search

    I. Lacatusu; N. Badea; A. Murariu; O. Oprea; D. Bojin; A. Meghea

    2011-01-01

    The objective of this investigation was to develop solid lipid nanoparticles (SLNs) of umbelliferone by means of high shear homogenization technique and to evaluate the efficiency of SLN systems in preserving and enhancing antioxidant activity of flavonoid active component. The aqueous SLN dispersions combine two structural types of lipid compounds and different types of emulsifiers including a mixture of monoalkyl

  19. Differential interaction of Sophora isoflavonoids with lipid bilayers

    Microsoft Academic Search

    Andrzej Boguslaw Hendrich; Rafal Malon; Andrzej Pola; Yoshiaki Shirataki; Noboru Motohashi; Krystyna Michalak

    2002-01-01

    The mechanisms of some biological effects exerted by flavonoids (e.g. activity against lipid oxidation, multidrug resistance modulation) may involve their interactions with lipid bilayers. Due to variety of substituents attached to the flavonoid nucleus individual isoflavones significantly differ in their properties; in particular they may differently interact with membranes. For this reason we have investigated the interactions of different isoflavones

  20. Partition of sodium dodecyl sulfate into stratum corneum lipid liposomes

    Microsoft Academic Search

    D. T. Downing; W. Abraham; B. K. Wegner; K. W. Willman; J. L. Marshall

    1993-01-01

    Synthetic detergents produce deleterious effects on human skin as the result of being taken up by the stratum corneum (SC). The present study aimed to determine to what extent a typical detergent enters the SC lipid lamellae, and what effect this might have on the physical properties of the lipids. These effects were studied in large unilamellar liposomes prepared from

  1. Liquid ionic matrixes for MALDI mass spectrometry imaging of lipids

    Microsoft Academic Search

    Céline Meriaux; Julien Franck; Maxence Wisztorski; Michel Salzet; Isabelle Fournier

    2010-01-01

    Lipids are a major component of cells and play a variety of roles in organisms. In general, they play a key role in the structural composition of membranes. Some lipids, such as sphingoglycolipids, however, are also mediators of different biological processes, including protein transport, regulation of cell growth, cellular morphogenesis, neuronal plasticity, and regulation of the immune response. With the

  2. MALDI imaging of lipids after matrix sublimation\\/deposition

    Microsoft Academic Search

    Robert C. Murphy; Joseph A. Hankin; Robert M. Barkley; Karin A. Zemski Berry

    2011-01-01

    Mass spectrometric techniques have been developed to record mass spectra of biomolecules including lipids as they naturally exist within tissues and thereby permit the generation of images displaying the distribution of specific lipids in tissues, organs, and intact animals. These techniques are based on matrix-assisted laser desorption\\/ionization (MALDI) that requires matrix application onto the tissue surface prior to analysis. One

  3. Relationship between plant lipid bodies and fungal endophytes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lipid bodies are universal components of plant cells and provide a mobilized carbon source for essential biological processes. Plant oils harvested for food and fuel often reside in these lipid bodies. Plants also host diverse populations of endophytic fungi, which easily escape microscopic detect...

  4. Lipid Vesicles as Membrane Models for Toxicological Assessment of Xenobiotics

    Microsoft Academic Search

    Helmut H. Zepik; Peter Walde; Elisabet L. Kostoryz; Jim Code; David M. Yourtee

    2008-01-01

    Traditionally animals and cell cultures have been used to assess the toxic potential of xenobi- otics on cell membranes. In search for more reproducible, quantitative, cost- and time-effective assays, toxicologists have recently become interested in biomimetic lipid vesicle-based test sys- tems. Lipid vesicles (liposomes) have long been appreciated as simple cell membrane models in biochemical and biophysical studies providing a

  5. Influences of lipid-modifying agents on hemostasis

    Microsoft Academic Search

    Cesare R. Sirtori; Susanna Colli

    1993-01-01

    Drugs affecting lipid metabolism may influence, to a variable extent, the hemostatic system, that is, platelet activation, fibrinogen, and fibrinolysis. These effects may or may not be linked to the activity of these compounds on the lipid\\/lipoprotein profile. For this reason it may be important to consider the effects of hypolipidemic drugs on the different aspects of hemostasis, because this

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

    SciTech Connect

    Dombrecht, E.J. [Immunology, Allergology and Rheumatology, Faculty of Medicine, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium); De Tollenaere, C.B. [Immunology, Allergology and Rheumatology, Faculty of Medicine, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium); Aerts, K. [Immunology, Allergology and Rheumatology, Faculty of Medicine, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium); Cos, P. [Laboratory of Microbiology, Parasitology and Hygiene (LMPH), Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium); Schuerwegh, A.J. [Immunology, Allergology and Rheumatology, Faculty of Medicine, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium); Bridts, C.H. [Immunology, Allergology and Rheumatology, Faculty of Medicine, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium); Van Offel, J.F. [Immunology, Allergology and Rheumatology, Faculty of Medicine, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium); Ebo, D.G. [Immunology, Allergology and Rheumatology, Faculty of Medicine, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium); Stevens, W.J. [Immunology, Allergology and Rheumatology, Faculty of Medicine, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium)]. E-mail: immuno@ua.ac.be; De Clerck, L.S. [Immunology, Allergology and Rheumatology, Faculty of Medicine, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp (Belgium)

    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.

  7. Adiponectin Reduces Lipid Accumulation in Macrophage Foam Cells

    PubMed Central

    Tian, Ling; Luo, Nanlan; Klein, Richard L.; Chung, B Hong; Garvey, W. Timothy; Fu, Yuchang

    2009-01-01

    Adiponectin is one of several, important metabolically active cytokines secreted from adipocytes. Low circulating levels of this adipokine have been associated epidemiologically with obesity, insulin resistance, type II diabetes, and cardiovascular disease. To determine if adiponectin can modulate lipid metabolism in macrophages, we expressed the adiponectin gene in human THP-1 macrophage foam cells using a lentiviral vector expression system and demonstrated that macrophages transduced with the adiponectin gene had decreased lipid accumulation compared with control macrophages transduced with the LacZ gene. Macrophages transduced with the adiponectin gene also exhibited decreased oxidized low-density lipoprotein (oxLDL) uptake and increased HDL-mediated cholesterol efflux. Additional studies suggest two potential mechanisms for the reduced lipid accumulation in these adiponectin-transduced macrophage foam cells. The first mechanism involves the PPAR? and LXR signaling pathways which up-regulate the expression of ABCA1 and promote lipid efflux from these cells. The second mechanism involves decreased lipid uptake and increased lipid hydrolysis which may result from decreased SR-AI and increased SR-BI and HSL gene activities in the transformed macrophage foam cells. We demonstrated also that the expression of two proatherogenic cytokines, MCP-1 and TNF?, were decreased in the adiponectin transduced macrophage foam cells. These results suggest that adiponectin may modulate multiple pathways of lipid metabolism in macrophages. Our studies provide new insights into potential mechanisms of adiponectin-mediated alterations in lipid metabolism and macrophage foam cell formation which may impact the development of atherosclerosis. PMID:18511057

  8. Controlling release from the lipidic cubic phase by selective alkylation

    E-print Network

    Craciun, Gheorghe

    Abstract The lipidic cubic phase can be viewed as a molecular sponge consisting of interpenetrating simplicity, it has a rich mesomorphism, as illustrated in the temperature­composition phase dia- gram shownControlling release from the lipidic cubic phase by selective alkylation J. Clogstona , G. Craciunb

  9. 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

  10. Halogenated compounds as inducers of lipid peroxidation in tissue slices.

    PubMed

    Fraga, C G; Leibovitz, B E; Tappel, A L

    1987-01-01

    Twenty-seven halogenated compounds were screened as potential inducers of lipid peroxidation in rat liver, kidney, spleen, and testes slices. In addition to the known lipid peroxidation inducers--carbon tetrachloride and bromotrichloromethane--the novel compounds carbon tetrabromide, p-bromobenzyl bromide, and benzyl bromide increased lipid peroxidation in each of the tissues studied. Lipid peroxidation was measured by release of thiobarbituric acid-reactive substances (TBARS) from the tissue slices. The amount of TBARS released from liver slices incubated with bromotrichloromethane, carbon tetrabromide, dichloromethane, bromobenzene, chloroform, bromoform, benzyl chloride, bromochloromethane, and carbon tetrabromide correlated with the lethality of these compounds as evaluated by their oral LD50 in rats. The lethality of a number of the compounds tested did not correlate with their capacity to induce lipid peroxidation. PMID:3666515

  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. 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

  14. Lipid peroxidation is essential for ?-synuclein-induced cell death

    PubMed Central

    Angelova, Plamena R.; Horrocks, Mathew H.; Klenerman, David; Gandhi, Sonia; Abramov, Andrey Y.; Shchepinov, Mikhail S.

    2015-01-01

    Parkinson’s disease is the second most common neurodegenerative disease and its pathogenesis is closely associated with oxidative stress. Deposition of aggregated ?-synuclein (?-Syn) occurs in familial and sporadic forms of Parkinson’s disease. Here, we studied the effect of oligomeric ?-Syn on one of the major markers of oxidative stress, lipid peroxidation, in primary co-cultures of neurons and astrocytes. We found that oligomeric but not monomeric ?-Syn significantly increases the rate of production of reactive oxygen species, subsequently inducing lipid peroxidation in both neurons and astrocytes. Pre-incubation of cells with isotope-reinforced polyunsaturated fatty acids (D-PUFAs) completely prevented the effect of oligomeric ?-Syn on lipid peroxidation. Inhibition of lipid peroxidation with D-PUFAs further protected cells from cell death induced by oligomeric ?-Syn. Thus, lipid peroxidation induced by misfolding of ?-Syn may play an important role in the cellular mechanism of neuronal cell loss in Parkinson’s disease. PMID:25580849

  15. Nuclear magnetic resonance imaging of lipid in living plants.

    PubMed

    Borisjuk, Ljudmilla; Rolletschek, Hardy; Neuberger, Thomas

    2013-10-01

    This review highlights technological developments in magnetic resonance imaging (MRI), which are creating opportunities for the three dimensional visualization and quantification of lipids in plant materials. A major feature of MRI is that it is a non-invasive platform, and thus can be used for the analysis of living organisms. An overview of the theoretical aspects of MRI is provided, followed by a description of the various analytical modes available, and an explanation of how MRI can be applied to plant samples and what it can achieve. Various lipid maps and three dimensional models of seeds and fruits are included to demonstrate the potential of MRI and to exemplify recent cutting-edge advances in the field. The importance and prospects of the imaging of lipids in living plants, as well as the integration of lipid imaging with other emerging techniques, are outlined to provide impetus for future plant lipid research. PMID:23748080

  16. Quantitative analysis of lipid deposits from Schnyder's corneal dystrophy

    PubMed Central

    Yamada, M.; Mochizuki, H.; Kamata, Y.; Nakamura, Y.; Mashima, Y.

    1998-01-01

    AIM—To report the quantitation of the lipid composition of a corneal button from a Japanese woman in her 60s with clinically and histopathologically proved Schnyder's corneal dystrophy.?METHODS—Total lipids extracted from the corneal button of the patient were analysed by the method of thin layer chromatography flame ionisation detection. Two different solvent systems were used for neutral lipid analysis and phospholipid analysis. Results were compared with three age matched corneal buttons obtained from cadaveric eyes.?RESULTS—The lipids that accumulated in the cornea in Schnyder's dystrophy consisted mainly of unesterified cholesterol and phospholipids. The analysis of phospholipids showed sphingomyelin to be the predominant phospholipid in the patient's cornea.?CONCLUSION—Findings suggest that this disorder involves a disturbance of the metabolism of cholesterol and/or sphingomyelin metabolism that is limited to the cornea.?? Keywords: Schnyder's dystrophy; lipids; unesterified cholesterol; sphingomyelin PMID:9640198

  17. 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.

  18. Antitumoral alkylphospholipids alter cell lipid metabolism.

    PubMed

    Marco, Carmen; Ríos-Marco, Pablo; Jiménez-López, Jose M; Segovia, Josefa L; Carrasco, María P

    2014-05-01

    Alkylphospholipid (APL) analogues are promising candidates in the search for treatments for cancer. In contrast to standard chemotherapeutic drugs, these lipophilic agents target the cell membrane without interacting directly with DNA. A variety of mechanisms have been suggested to explain the actions of these compounds, which can induce apoptosis and/or cell growth arrest. In this review, we focus on recent advances in our understanding of the actions of clinically-relevant APLs, such as hexadecylphosphocholine (HePC), edelfosine, erucylphosphocholine (ErPC) and perifosine on the human hepatoma HepG2 cell line, which is commonly used for lipid metabolism studies with a special emphasis on cholesterol metabolism. One consistent finding is that HePC and other APLs cause a reduction in the biosynthesis of phosphatidylcholine (PC) by inhibiting the rate-limiting enzyme CTP:phosphocholine cytidylyltransferase (CT). Our research group has been at the forefront in demonstrating that exposure to APLs affects cholesterol homeostasis in mammalian cells. Treatment with HePC, for example, causes a marked enhancement in cholesterol synthesis, which has been related to an impairment in the arrival of cholesterol at the endoplasmic reticulum (ER). In a similar way to HePC, edelfosine, ErPC and perifosine increase the de novo synthesis and uptake of cholesterol and also inhibit the arrival of plasma-membrane cholesterol at the ER, which induces a significant cholesterogenic response in these cells, involving an increase in gene expression and higher levels of several proteins related to the biosynthetic pathway and receptor-mediated uptake of cholesterol. It is generally accepted nowadays that the maintenance of a tightly controlled free-cholesterol/PC ratio is crucial to optimum cell behaviour and that alterations to this ratio may lead to necrosis and/or apoptosis. Our results have considerable bearing on this idea because an increase in cholesterol biosynthesis associated with a decrease in the synthesis of choline-containing phospholipids and cholesterol esterification leads to a modification in the free-cholesterol/PC ratio in cells exposed to APLs. It is well accepted that cholesterol is critical for the formation of lipid rafts and therefore drugs that alter cell cholesterol content should modify the properties of these membrane domains and consequently the signal-transduction pathways, which depends upon lipid-raft integrity. Results on the whole show that APLs share a common active mechanism consisting of disrupting PC and sphingomyelin (SM) biosyntheses and cholesterol homeostasis, all of which leads to a disturbance in the native membrane structure, thus affecting signaling processes vital to cell survival and growth. PMID:24628237

  19. 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...

  20. Derlin-1 and UBXD8 are engaged in dislocation and degradation of lipidated ApoB-100 at lipid droplets.

    PubMed

    Suzuki, Michitaka; Otsuka, Toshihiko; Ohsaki, Yuki; Cheng, Jinglei; Taniguchi, Takako; Hashimoto, Hisashi; Taniguchi, Hisaaki; Fujimoto, Toyoshi

    2012-03-01

    Apolipoprotein B-100 (ApoB) is the principal component of very low density lipoprotein. Poorly lipidated nascent ApoB is extracted from the Sec61 translocon and degraded by proteasomes. ApoB lipidated in the endoplasmic reticulum (ER) lumen is also subjected to proteasomal degradation, but where and how it dislocates to the cytoplasm remain unknown. In the present study, we demonstrate that ApoB after lipidation is dislocated to the cytoplasmic surface of lipid droplets (LDs) and accumulates as ubiquitinated ApoB in Huh7 cells. Depletion of UBXD8, which is almost confined to LDs in this cell type, decreases recruitment of p97 to LDs and causes an increase of both ubiquitinated ApoB on the LD surface and lipidated ApoB in the ER lumen. In contrast, abrogation of Derlin-1 function induces an accumulation of lipidated ApoB in the ER lumen but does not increase ubiquitinated ApoB on the LD surface. UBXD8 and Derlin-1 bind with each other and with lipidated ApoB and show colocalization around LDs. These results indicate that ApoB after lipidation is dislocated from the ER lumen to the LD surface for proteasomal degradation and that Derlin-1 and UBXD8 are engaged in the predislocation and postdislocation steps, respectively. PMID:22238364

  1. Lipid profiling of the Arabidopsis hypersensitive response reveals specific lipid peroxidation and fragmentation processes: biogenesis of pimelic and azelaic acid.

    PubMed

    Zoeller, Maria; Stingl, Nadja; Krischke, Markus; Fekete, Agnes; Waller, Frank; Berger, Susanne; Mueller, Martin J

    2012-09-01

    Lipid peroxidation (LPO) is induced by a variety of abiotic and biotic stresses. Although LPO is involved in diverse signaling processes, little is known about the oxidation mechanisms and major lipid targets. A systematic lipidomics analysis of LPO in the interaction of Arabidopsis (Arabidopsis thaliana) with Pseudomonas syringae revealed that LPO is predominantly confined to plastid lipids comprising galactolipid and triacylglyceride species and precedes programmed cell death. Singlet oxygen was identified as the major cause of lipid oxidation under basal conditions, while a 13-lipoxygenase (LOX2) and free radical-catalyzed lipid oxidation substantially contribute to the increase upon pathogen infection. Analysis of lox2 mutants revealed that LOX2 is essential for enzymatic membrane peroxidation but not for the pathogen-induced free jasmonate production. Despite massive oxidative modification of plastid lipids, levels of nonoxidized lipids dramatically increased after infection. Pathogen infection also induced an accumulation of fragmented lipids. Analysis of mutants defective in 9-lipoxygenases and LOX2 showed that galactolipid fragmentation is independent of LOXs. We provide strong in vivo evidence for a free radical-catalyzed galactolipid fragmentation mechanism responsible for the formation of the essential biotin precursor pimelic acid as well as of azelaic acid, which was previously postulated to prime the immune response of Arabidopsis. Our results suggest that azelaic acid is a general marker for LPO rather than a general immune signal. The proposed fragmentation mechanism rationalizes the pathogen-induced radical amplification and formation of electrophile signals such as phytoprostanes, malondialdehyde, and hexenal in plastids. PMID:22822212

  2. Direct Visualization of Lipid Domains in Human Skin Stratum Corneum's Lipid Membranes: Effect of pH and Temperature

    Microsoft Academic Search

    I. Plasencia; L. Norlen; L. A. Bagatolli

    2007-01-01

    The main function of skin is to serve as a physical barrier between the body and the environment. This barrier capacity is in turn a function of the physical state and structural organization of the stratum corneum extracellular lipid matrix. This lipid matrix is essentially composed of very long chain saturated ceramides, cholesterol, and free fatty acids. Three unsolved key

  3. Potent and selective alpha-ketoheterocycle-based inhibitors of the anandamide and oleamide catabolizing enzyme, fatty acid amide hydrolase.

    PubMed

    Romero, F Anthony; Du, Wu; Hwang, Inkyu; Rayl, Thomas J; Kimball, F Scott; Leung, Donmienne; Hoover, Heather S; Apodaca, Richard L; Breitenbucher, J Guy; Cravatt, Benjamin F; Boger, Dale L

    2007-03-01

    A study of the structure-activity relationships (SAR) of 2f (OL-135), a potent inhibitor of fatty acid amide hydrolase (FAAH), is detailed, targeting the 5-position of the oxazole. Examination of a series of substituted benzene derivatives (12-14) revealed that the optimal position for substitution was the meta-position with selected members approaching or exceeding the potency of 2f. Concurrent with these studies, the effect of substitution on the pyridine ring of 2f was also examined. A series of small, nonaromatic C5-substituents was also explored and revealed that the K(i) follows a well-defined correlation with the Hammett sigma(p) constant (rho = 3.01, R2 = 0.91) in which electron-withdrawing substituents enhance potency, leading to inhibitors with K(i)s as low as 400 pM (20n). Proteomic-wide screening of the inhibitors revealed that most are exquisitely selective for FAAH over all other mammalian proteases, reversing the 100-fold preference of 20a (C5 substituent = H) for the enzyme TGH. PMID:17279740

  4. Lipid composition in atheromatous plaque: evaluation of the lipid three-phase percentage.

    PubMed

    Marinello, Enrico; Setacci, Carlo; Giubbolini, Michele; Cinci, Giuliano; Frosi, Barbara; Porcelli, Brunetta; Terzuoli, Lucia

    2003-05-01

    There is a renewed interest in the study of plaque lipid composition because it is recognized that it, rather than the luminal narrowing, influences the plaque stability and determines patient symptoms. At this purpose, we quantitatively evaluated in the carotid plaque of different categories of patients the expression of triglycerides, phospholipids, cholesterol, free cholesterol, esters of cholesterol, and the percentages of the three-phases (cholesterol, esters of cholesterol, phospholipids) by using the "Roozeboom triangle". Significant differences in the content of specific lipid and the percentage of the three-phases were detected among the different types of plaque evaluated in this study. The analysis of the three-phases by "Roozeboom triangle" may open a new approach in the study of atheromatous plaque and give new information on development of the disease. PMID:12679186

  5. Size and structure of spontaneously forming liposomes in lipid/PEG-lipid mixtures.

    PubMed Central

    Rovira-Bru, Montse; Thompson, David H; Szleifer, Igal

    2002-01-01

    The optimal size and structure of spontaneous liposomes formed from lipid/polymer-lipid mixtures was calculated using a molecular mean-field theory. The equilibrium properties of the aggregate are obtained by expanding the free energy of a symmetric planar bilayer up to fourth order in curvature and composition of lipid and polymer. The expansion coefficients are obtained from a molecular theory that explicitly accounts for the conformational degrees of freedom of the hydrophobic tails of the lipid and of the polymer chains. The polar headgroup interactions are treated using the opposing forces model. The onset of stability of the symmetric planar film is obtained from the expansion up to quadratic order. For unstable planar films the equilibrium size and structure of the spherical aggregates is obtained from the second- and fourth-order terms in curvature and composition of lipid and polymer. The driving force for the formation of spontaneous vesicles is the asymmetric distribution of polymers between the inner and outer monolayer. The composition asymmetry between the two monolayers in the aggregates is much larger for the polymer component than for the lipid, and it depends upon the size of the aggregate. The smaller the aggregate, the more asymmetric the distribution of polymer and lipid. The tendency of the polymer chains to be tethered on the outer surface of the aggregate is very strong, and it limits the range of polymer loading for which spherical liposomes are stable. A very small excess of polymer loading causes small spherical micelles to be the optimal aggregates. In these cases spontaneous liposomes can form as metastable aggregates, showing as a local minima in the free energy. Even for metastable aggregates the asymmetric distribution of polymers is very large. The elastic constants of the asymmetric bilayer in the spherical aggregate are found to be the same as those that are calculated from the planar symmetric film. Therefore, the stable structure of the aggregate is not needed to determine its mechanical properties. The range of stable liposomes is very narrow in the range of molecular weights studied, which include the experimental relevant domain of aggregates used in drug delivery. It is found that the stability of the spherical aggregates results from a very fine balance between the tendency of the polymer chains and lipid tails to pack in an asymmetric spherical aggregate and the tendency of the hydrophobic-water interface to keep the area per molecule fixed. The changes in free energy per molecules that are responsible for liposome formation are very small and are very sensitive to detailed molecular properties. The theoretical description of the aggregates requires a theory capable of incorporating these detailed molecular properties. The findings are discussed in the context of vesicle formation and liposome design for drug delivery. PMID:12414678

  6. 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

  7. In vitro performance of lipid-PLGA hybrid nanoparticles as an antigen delivery system: lipid composition matters

    PubMed Central

    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

  8. 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

  9. 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

  10. Bacterial predators possess unique membrane lipid structures.

    PubMed

    Müller, Frederic D; Beck, Sebastian; Strauch, Eckhard; Linscheid, Michael W

    2011-12-01

    Bdellovibrio-and-like organisms (BALO) are a phylogenetically diverse group of predatory prokaryotes that consists of the two families Bdellovibrionaceae and Bacteriovoracaceae. We investigated the phospholipid composition of the three important BALO strains Bacteriovorax stolpii (DSM 12778), Bdellovibrio bacteriovorus HD100 (DSM 50701) and Peredibacter starrii (DSM 17039). We confirmed the presence of sphingophosphonolipids in B. stolpii, while we characterized sphingophosphonolipids with a 2-amino-3-phosphonopropanate head group for the first time. In B. bacteriovorus HD100 phosphatidylthreonines were found and, thus, B. bacteriovorus is the second prokaryote investigated so far possessing this rare lipid class. In the third analyzed organism, P. starrii, we observed phosphatidylethanolamine structures with an additional N-glutamyl residue, which form the first reported class of amino acid-containing phosphatidylethanolamines. PMID:21984111

  11. Mathematical modelling of hepatic lipid metabolism.

    PubMed

    Pratt, Adrian C; Wattis, Jonathan A D; Salter, Andrew M

    2015-04-01

    The aim of this paper is to develop a mathematical model capable of simulating the metabolic response to a variety of mixed meals in fed and fasted conditions with particular emphasis placed on the hepatic triglyceride element of the model. Model validation is carried out using experimental data for the ingestion of three mixed composition meals over a 24-h period. Comparison with experimental data suggests the model predicts key plasma lipids accurately given a prescribed insulin profile. One counter-intuitive observation to arise from simulations is that liver triglyceride initially decreases when a high fat meal is ingested, a phenomenon potentially explained by the carbohydrate portion of the meal raising plasma insulin. PMID:25645182

  12. Phenolic lipid ingredients from cashew nuts

    Microsoft Academic Search

    Maorong Suo; Hasegawa Isao; Yoshihiro Ishida; Yasoku Shimano; Changxiao Bi; Hikaru Kato; Fumihide Takano; Tomihisa Ohta

    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

  13. Lipid Rafts in Mast Cell Biology

    PubMed Central

    Silveira e Souza, Adriana Maria Mariano; Mazucato, Vivian Marino; Jamur, Maria Célia; Oliver, Constance

    2011-01-01

    Mast cells have long been recognized to have a direct and critical role in allergic and inflammatory reactions. In allergic diseases, these cells exert both local and systemic responses, including allergic rhinitis and anaphylaxis. Mast cell mediators are also related to many chronic inflammatory conditions. Besides the roles in pathological conditions, the biological functions of mast cells include roles in innate immunity, involvement in host defense mechanisms against parasites, immunomodulation of the immune system, tissue repair, and angiogenesis. Despite their growing significance in physiological and pathological conditions, much still remains to be learned about mast cell biology. This paper presents evidence that lipid rafts or raft components modulate many of the biological processes in mast cells, such as degranulation and endocytosis, play a role in mast cell development and recruitment, and contribute to the overall preservation of mast cell structure and organization. PMID:21490812

  14. Crystallizing Transmembrane Peptides in Lipidic Mesophases

    SciTech Connect

    Höfer, Nicole; Aragăo, David; Caffrey, Martin (Trinity)

    2011-09-28

    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 {le}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.

  15. Mesoscopic Lateral Diffusion in Lipid Bilayers

    PubMed Central

    Ayton, Gary S.; Voth, Gregory A.

    2004-01-01

    The lateral diffusion in bilayers is modeled with a multiscale mesoscopic simulation. The methodology consists of two simulations, where the first employs atomistic models to obtain exact results for the mesoscopic model. The second simulation takes the results obtained from the first to parameterize an effective force field that is employed in a new coarse-grained model. The multiscale aspect of this scheme occurs at the point where the microscopic time-averaged results of the first simulation are employed to parameterize the second simulation that operates in a higher spatial and temporal domain. The results of both simulation schemes give quantitative information on the details associated with lipid lateral diffusion. PMID:15339807

  16. Cytokine and lipid mediator networks in tuberculosis.

    PubMed

    Mayer-Barber, Katrin D; Sher, Alan

    2015-03-01

    A major approach for immunologic intervention in tuberculosis involves redirecting the outcome of the host immune response from the induction of disease to pathogen control. Cytokines and lipid mediators known as eicosanoids play key roles in regulating this balance and as such represent important targets for immunologic intervention. While the evidence for cytokine/eicosanoid function derives largely from the investigation of murine and zebrafish experimental infection models, clinical studies have confirmed the existence of many of the same pathways in tuberculosis patients. Here, we summarize new data that reveal important intersections between the cytokine and eicosanoid networks in the host response to mycobacteria and discuss how targeting this crosstalk can promote resistance to lethal Mycobacterium tuberculosis infection. This approach could lead to new host-directed therapies to be used either as an adjunct for improving the efficacy of standard antibiotic treatment or for the management of drug-resistant infections. PMID:25703565

  17. Lipid-Mediated Interactions between Intrinsic Membrane Proteins: Dependence on Protein Size and Lipid Composition

    Microsoft Academic Search

    Patrick Lagüe; Martin J. Zuckermann; Benoit Roux

    2001-01-01

    The present study is an application of an approach recently developed by the authors for describing the structure of the hydrocarbon chains of lipid-bilayer membranes (LBMs) around embedded protein inclusions (Lagüe et al., 2000 Biophys. J. 79:2867–2879). The approach is based on statistical mechanical integral equation theories developed for the study of dense liquids. First, the configurations extracted from molecular

  18. Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) in cosmetic and dermatological preparations

    Microsoft Academic Search

    R. H. Müller; M. Radtke; S. A. Wissing

    2002-01-01

    Solid lipid nanoparticles (SLN) were developed at the beginning of the 1990s as an alternative carrier system to emulsions, liposomes and polymeric nanoparticles. The paper reviews advantages—also potential limitations—of SLN for the use in topical cosmetic and pharmaceutical formulations. Features discussed include stabilisation of incorporated compounds, controlled release, occlusivity, film formation on skin including in vivo effects on the skin.

  19. [Ordering of lipids and lipid-protein complexes in molluscan mucus and human bile].

    PubMed

    Varshavskaia, O A; Klass, S M; Ze?fert, D V; Kononenko, E V

    1983-01-01

    Optic-morphological characteristics and crystallization of mucus of land snails Achatina fulica (Bowditch) are compared with cervical secret and also with the human bile. Typical defective structures of mesophases: spheroliths, regions of confocal and fan textures containing various classes of line defects are shown. Crystallization of protein and lipid fractions is shown to proceed separately, while the dendrite mechanism is typical for the former and for the latter the dislocational growth of crystals from the mesophase is possible. PMID:6871265

  20. lipids 30%, proteins 4%), a high isocaloric (634 Kcal) protein diet (glucids 50%, lipids

    E-print Network

    Paris-Sud XI, Université de

    %, proteins 20%) or a free diet at break- fast for a period of 4 weeks. At the end of each week and 3 h after.009) and lipidic calories (P=0.002), but not with pro- tein intake. In conclusion, the total intake of nutri- ments protein lev- els (10 or 20% casein). The food was avail- able for 8 h, blood and tissue sampling

  1. Lipid peroxidation in rats chronically fed ethanol.

    PubMed

    Teare, J P; Greenfield, S M; Watson, D; Punchard, N A; Miller, N; Rice-Evans, C A; Thompson, R P

    1994-11-01

    Chronic alcohol consumption induces cytochrome P450IIE1, enabling habitual abusers to consume far greater quantities of alcohol than normal subjects. This pathway of metabolism leads to the production of free radical species, which cause tissue damage through peroxidation of cell membranes. Groups of Wistar rats of equal male: female ratio (n = 24) were fed alcohol by gavage twice daily to achieve a dosage of 15 g/kg body weight. Mean peak blood alcohol concentrations of 186 mg% were produced in males and 156 mg% in females. The animals were allowed free access to standard laboratory chow and water. Control animals were pair-fed to the alcoholic group and fed isocaloric glucose by gavage. Groups of animals were killed between 9 and 11 am on consecutive mornings, after nocturnal feeding, since it has previously been shown that fasting rapidly depletes hepatic glutathione concentrations. Hepatic glutathione was measured by a spectrophotometric enzymatic recycling procedure. As a marker of lipid peroxidation hepatic malonaldehyde (MDA) was measured by high performance liquid chromatography. Hepatic MDA was increased in the alcoholic group (p < 0.001), as was total hepatic glutathione (p < 0.0001). Plasma concentrations of alpha-tocopherol were increased in the alcoholic group, but ascorbic acid and superoxide dismutase values were not affected. No sex differences were detected. The increased MDA production in the alcohol group is strong evidence that lipid peroxidation is a mechanism of alcoholic tissue damage. The rise in hepatic glutathione may be an adaptive response to free radical production that protects the rat against tissue damage. PMID:7828990

  2. 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

  3. Lipid Bilayer Vesicle Generation Using Microfluidic Jetting

    PubMed Central

    Coyne, Christopher W.; Patel, Karan; Heureaux, Johanna; Stachowiak, Jeanne; Fletcher, Daniel A.; Liu, Allen P.

    2014-01-01

    SHORT ABSTRACT Microfluidic jetting against a droplet interface lipid bilayer provides a reliable way to generate vesicles with control over membrane asymmetry, incorporation of transmembrane proteins, and encapsulation of material. This technique can be applied to study a variety of biological systems where compartmentalized biomolecules are desired. LONG ABSTRACT Bottom-up synthetic biology presents a novel approach for investigating and reconstituting biochemical systems and, potentially, minimal organisms. This emerging field engages engineers, chemists, biologists, and physicists to design and assemble basic biological components into complex, functioning systems from the bottom up. Such bottom-up systems could lead to the development of artificial cells for fundamental biological inquiries and innovative therapies1,2. Giant unilamellar vesicles (GUVs) can serve as a model platform for synthetic biology due to their cell-like membrane structure and size. Microfluidic jetting, or microjetting, is a technique that allows for the generation of GUVs with controlled size, membrane composition, transmembrane protein incorporation, and encapsulation3. The basic principle of this method is the use of multiple, high-frequency fluid pulses generated by a piezo-actuated inkjet device to deform a suspended lipid bilayer into a GUV. The process is akin to blowing soap bubbles from a soap film. By varying the composition of the jetted solution, the composition of the encompassing solution, and/or the components included in the bilayer, researchers can apply this technique to create customized vesicles. This paper describes the procedure to generate simple vesicles from a droplet interface bilayer by microjetting. PMID:24637415

  4. [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.

  5. Lipid-lowering therapy: who can benefit?

    PubMed

    Lewis, Sandra J

    2011-01-01

    Cardiovascular disease (CVD) is the leading cause of death in the US. Despite the decline in CVD-associated mortality rates in recent years, coronary heart disease (CHD) still causes one in every six deaths in this country. Because most CHD risk factors are modifiable (eg, smoking, hypertension, obesity, onset of type 2 diabetes, and dyslipidemia), cardiovascular risk can be reduced by timely and appropriate interventions, such as smoking cessation, diet and lifestyle changes, and lipid-modifying therapy. Dyslipidemia, manifested by elevated low-density lipoprotein cholesterol (LDL-C), is central to the development and progression of atherosclerosis, which can be silent for decades before triggering a first major cardiovascular event. Consequently, dyslipidemia has become a primary target of intervention in strategies for the prevention of cardiovascular events. The guidelines of the Adult Treatment Panel (ATP) III, updated in 2004, recommend therapeutic lifestyle changes and the use of lipid-lowering medications, such as statins, to achieve specific LDL-C goals based on a person's global cardiovascular risk. For high-risk individuals, such as patients with CHD and diabetic patients without CHD, an LDL-C target of < 100 mg/dL is recommended, and statin therapy should be considered to help patients achieve this goal. If correctly dosed in appropriate patients, currently approved statins are generally safe and provide significant cardiovascular benefits in diverse populations, including women, the elderly, and patients with diabetes. A recent primary prevention trial also showed that statins benefit individuals traditionally not considered at high risk of CHD, such as those with no hyperlipidemia but elevated C-reactive protein. Additional evidence suggests that statins may halt or slow atherosclerotic disease progression. Recent evidence confirms the pivotal role of statins in primary and secondary prevention. PMID:21915170

  6. Anionic Lipids Are Required for Vesicular Stomatitis Virus G Protein-mediated Single Particle Fusion with Supported Lipid Bilayers*

    PubMed Central

    Matos, Pedro M.; Marin, Mariana; Ahn, Byungwook; Lam, Wilbur; Santos, Nuno C.; Melikyan, Gregory B.

    2013-01-01

    Viral glycoproteins mediate fusion between viral and cellular membranes upon binding to cognate receptors and/or experiencing low pH. Although activation of viral glycoproteins is thought to be necessary and sufficient for fusion, accumulating evidence suggests that additional cellular factors, including lipids, can modulate the fusion process. Understanding the role of lipids in virus entry via endocytosis is impeded by poor accessibility and the highly diverse nature of endosomes. Here we imaged fusion of single retroviral particles pseudotyped with the vesicular stomatitis virus (VSV) G protein with dextran-supported lipid bilayers. Incorporation of diffusible fluorescent labels into the viral membrane and the viral interior enabled detection of the lipid mixing (hemifusion) and content transfer (full fusion) steps of VSV G-mediated fusion at low pH. Although single virus fusion with supported bilayers made of zwitterionic lipids could not be detected, inclusion of anionic lipids, phosphatidylserine, and bis(monoacylglycero)phosphate (BMP), greatly enhanced the efficiency of hemifusion and permitted full fusion. Importantly, lipid mixing always preceded the opening of a fusion pore, demonstrating that VSV G-mediated fusion proceeds through a long-lived hemifusion intermediate. Kinetic analysis of lipid and content transfer showed that the lags between lipid and content mixing defining the lifetime of a hemifusion intermediate were significantly shorter for BMP-containing compared with PS-containing bilayers. The strong fusion-enhancing effect of BMP, a late endosome-resident lipid, is consistent with the model that VSV initiates fusion in early endosomes but releases its core into the cytosol after reaching late endosomal compartments. PMID:23493401

  7. Lipid target achievement among patients with very high and high cardiovascular risk in a lipid clinic.

    PubMed

    Barkas, Fotios; Liberopoulos, Evangelos N; Kostapanos, Michael S; Liamis, George; Tziallas, Dimitrios; Elisaf, Moses

    2015-04-01

    This was a retrospective study that assessed achievement of lipid-lowering treatment targets in the setting of a University Hospital Lipid Clinic. Low-density lipoprotein cholesterol (LDL-C) goal attainment according to National Cholesterol Education Program-Adult Treatment Panel III (NCEP ATP III) and European Society of Cardiology/European Atherosclerosis Society (ESC/EAS) guidelines was recorded in 1000 consecutive adult patients followed for ?3 years (mean 8 years). The LDL-C targets according to the NCEP ATP III were attained by 66% and 86% of patients with "very high" (n = 477) and "high" (n = 408) cardiovascular risk, respectively. Fewer patients were within LDL-C goals according to the ESC/EAS guidelines: 25% and 42%. Overall, 92% of the patients were on statins: 67% were on statin monotherapy, while 33% were on combinations with ezetimibe (25%), ?-3 fatty acids (5%), fibrates (4%), or colesevelam (2%). Even in a specialist lipid clinic, a large proportion of patients are not at goal according to the recent ESC/EAS guidelines. PMID:24830420

  8. Stratum corneum lipid abnormalities in ichthyosis. Detection by a new lipid microanalytical method.

    PubMed

    Brown, B E; Williams, M L; Elias, P M

    1984-02-01

    Although the biochemical diagnosis of the ichthyoses is still in its infancy, the two recessively inherited types, recessive X-linked ichthyosis (RXLI) and nonbullous congenital ichthyosiform erythroderma (CIE), are accompanied by stratum corneum lipid abnormalities. However, in RXLI, cholesterol sulfate accumulates; in CIE, massive quantities of n-alkanes accumulate. The diagnosis of these disorders has required large quantities of scale for sequential, quantitative thin-layer chromatography (TLC). In this study, we sought to confirm the previously described lipid abnormalities with the use of a rapid, recently developed microchromatographic technique that employs silica gel-coated quartz rods and flame ionization detection (Iatroscan). The cholesterol sulfate content of RXLI (n = 5) scale and the n-alkane content of CIE (n = 8) scale were determined by both TLC and the microchromatographic technique. Less than 10 mg of scale and even single punch biopsy specimens sufficed for the microchromatographic technique, whereas more than 50 mg of scale were required for TLC. Since the microchromatographic technique can rapidly detect diagnostic biochemical abnormalities from readily obtainable, small tissue samples, this method could eventually supplant or supplement standard lipid biochemical techniques for the diagnosis of cutaneous lipidoses. PMID:6696472

  9. Lipid metabolism in the cow during starvation-induced ketosis.

    PubMed Central

    Brumby, P E; Anderson, M; Tuckley, B; Storry, J E; Hibbit, K G

    1975-01-01

    1. Concentrations and compositions of liver, serum and milk lipids of cows were measured during 6 days' starvation and serum lipids during 60 days' re-feeding. 2. The concentration of free fatty acid in serum increased fivefold during starvation. 3. The content of total lipid in liver (g/100g of liver dry matter) doubled owing to a 20-fold increase in triglyceride, an eightfold increase in cholesterol ester, a three fold increase in free fatty acid and a 20% increase in cholesterol. There were no changes in the content or composition of liver phospholipids. 4. Starvation lowered the concentrations of total lipid, phospholipid and cholesterol ester of dextran sulphate-precipitable serum lipoproteins. Total lipid and cholesterol ester concentrations in lipoproteins of d greater than 1.055 and in lipoproteins not precipitable by dextran sulphate decreased from day 4 of the starvation period and during the first 20 days' re-feeding. 5. During starvation there were decreases in percentages of stearic acid and increases in oleic acid in serum free fatty acids and triglycerides and in liver neutral lipid. 6. Throughout starvation total milk lipid yield decreased, yields and percentages of C4-14 fatty acids decreased and percentages of C18 fatty acids increased. 7. It is suggested that accumulation of triglyceride in liver may be caused by increased uptake of plasma free fatty acids without corresponding increase in lipoprotein secretion. PMID:1170844

  10. Lipid metabolism in the cow during starvation-induced ketosis.

    PubMed

    Brumby, P E; Anderson, M; Tuckley, B; Storry, J E; Hibbit, K G

    1975-03-01

    1. Concentrations and compositions of liver, serum and milk lipids of cows were measured during 6 days' starvation and serum lipids during 60 days' re-feeding. 2. The concentration of free fatty acid in serum increased fivefold during starvation. 3. The content of total lipid in liver (g/100g of liver dry matter) doubled owing to a 20-fold increase in triglyceride, an eightfold increase in cholesterol ester, a three fold increase in free fatty acid and a 20% increase in cholesterol. There were no changes in the content or composition of liver phospholipids. 4. Starvation lowered the concentrations of total lipid, phospholipid and cholesterol ester of dextran sulphate-precipitable serum lipoproteins. Total lipid and cholesterol ester concentrations in lipoproteins of d greater than 1.055 and in lipoproteins not precipitable by dextran sulphate decreased from day 4 of the starvation period and during the first 20 days' re-feeding. 5. During starvation there were decreases in percentages of stearic acid and increases in oleic acid in serum free fatty acids and triglycerides and in liver neutral lipid. 6. Throughout starvation total milk lipid yield decreased, yields and percentages of C4-14 fatty acids decreased and percentages of C18 fatty acids increased. 7. It is suggested that accumulation of triglyceride in liver may be caused by increased uptake of plasma free fatty acids without corresponding increase in lipoprotein secretion. PMID:1170844

  11. 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

  12. Understanding and Analyzing Meibomian Lipids-A Review

    PubMed Central

    Butovich, Igor A.; Ham, Bryan M.

    2009-01-01

    Purpose This review is intended to bring to the informed reader the current state of knowledge about meibomian lipids and the art for analyzing them. Methods At the forefront of any endeavor, there are controversies, and these, along with future directions in the field, are brought to the reader's attention. Results Function and anatomy of meibomian glands are briefly covered, giving insight into possible mechanisms for secretory controls. Anatomically, some anomalies in meibomian gland distribution of different species, such as whales versus dolphins, are presented, and, for the first time, the structure of the meibomian glands in a selection of marsupials is presented. In attempting to make the literature more accessible, lipid structure and nomenclature are described, and these structures are related to their possible effects on the physicochemical properties of meibomian lipids. The advantages and disadvantages of various collection and storage techniques are described, as well as how gas chromatography and combined HPLC and mass spectrometry coupled with fragmentation are currently enabling us to determine the nature of the lipids in very small samples. Conclusions This review extends to discussing the lipids in tears (as opposed to meibomian gland lipids) and briefly highlights new thoughts about the interactions between proteins of the tear film and meibomian lipids. A model that includes proteins in the outer layer of the tear film is also presented. This model is currently being critically analyzed by the ocular community. It concludes briefly by highlighting possible further areas of research in this area. PMID:18568877

  13. Protein-independent lead permeation through myelin lipid liposomes.

    PubMed

    Díaz, R S; Monreal, J

    1995-04-01

    We have investigated the permeability of protein-free myelin lipid liposomes to inorganic lead by using the fluorescent probes fura-2, oxonol V, pyranine, and carboxyfluorescein. Inorganic lead readily crossed the lipid bilayer, as detected with fura-2, to an extent that depended on the external pH and the total nominal lead concentration in the assay medium. Lead entry generated an internally positive transmembrane potential, which could be detected by oxonol V fluorescence quenching, and dissipated a transmembrane pH gradient by alkalinization of the intravesicular space, as measured with pyranine. These results cannot be explained by lead-mediated nonspecific damage to membrane lipids, based on the following results 1) lead exposure did not increase carboxyfluorescein leakage from liposomes, 2) it did not increase the permeability of the lipid bilayer to glucose or KCl, 3) it did not generate peroxidation products in contact with myelin lipids, and 4) it did not induce chemical hydrolysis or modification of any myelin lipid class. We conclude that the principal molecular mechanism of lead permeation through a pure lipid bilayer is the passive diffusion of Pb(OH)+. We discuss the toxicological relevance of these findings for cells in general and for myelin in particular and suggest that this mechanism might contribute significantly to the total lead entry into the cells. PMID:7723737

  14. Dissolution of solid lipid extrudates in biorelevant media.

    PubMed

    Witzleb, R; Müllertz, A; Kanikanti, V-R; Hamann, H-J; Kleinebudde, P

    2012-01-17

    Solid lipid extrudates with the model drug praziquantel were produced with chemically diverse lipids and investigated regarding their dissolution behaviour in different media. The lipids used in this study were glyceryl tripalmitate, glyceryl dibehenate, glyceryl monostearate, cetyl palmitate and solid paraffin. Thermoanalytical and dissolution behaviour was investigated directly after extrusion and after 3 and 6 months open storage at 40°C/75% RH. Dissolution studies were conducted in hydrochloric acid (HCl) pH 1.2 with different levels of polysorbate 20 and with a biorelevant medium containing pancreatic lipase, bile salts and phospholipids. Furthermore, the impact of lipid digestion on drug release was studied using in vitro lipolysis. The release of praziquantel from cetyl palmitate and glyceryl monostearate in the biorelevant medium was much faster than in HCl, whereas there was hardly any difference for the other lipids. It was shown that drug release from glyceryl monostearate matrices is driven by both solubilisation and enzymatic degradation of the lipid, whereas dissolution from cetyl palmitate extrudates is dependent only on solubilisation by surfactants in the medium. Moreover, storage influenced the appearance of the extrudate surface and the dissolution rate for all lipids except solid paraffin. PMID:22044538

  15. Lipid nanotubes as substrates for helical crystallization of macromolecules

    PubMed Central

    Wilson-Kubalek, Elizabeth M.; Brown, Rhoderick E.; Celia, Hervé; Milligan, Ronald A.

    1998-01-01

    A general approach for crystallization of proteins in a fast and simple manner would be of immense interest to biologists studying protein structure–function relationships. Here, we describe a method that we have developed for promoting the formation of helical arrays of proteins and macromolecular assemblies. Electron micrographs of the arrays are suitable for helical image analysis and three-dimensional reconstruction. We show that hydrated mixtures of the glycolipid galactosylceramide (GalCer) and derivatized lipids or charged lipids form unilamellar nanotubules. The tubules bind proteins in a specific manner via high affinity ligands on the polar head groups of the lipid or via electrostatic interactions. By doping the GalCer with a novel nickel-containing lipid, we have been able to form helical arrays of two histidine-tagged proteins. Similarly, doping with a biotinylated lipid allows crystallization of streptavidin. Finally, three proteins with affinity for positively or negatively charged lipid layers formed helical arrays on appropriately charged tubules. The generality of this method may allow a wide variety of proteins to be crystallized on lipid nanotubes under physiological conditions. PMID:9653136

  16. DNA driven 2D Assembly of Nanoparticles on Lipid Surfaces

    NASA Astrophysics Data System (ADS)

    Srivastava, Sunita; Nykypanchuk, Dmytro; Gang, Oleg

    2011-03-01

    Use of biomolecular linkers such as DNA due to its sequence-specific hybridization properties provides a versatile platform for assembly of nanoscale components. Here we investigated the DNA-based self-assembly of gold nanoparticles in 2D using lipid layer as fluid substrate. We examined the effect of lipid composition by vary the fraction of cationic and zwitterion lipids on formation of a particle monolayer. Using in-situ X -ray reflectivity we observed adsorption of DNA functionalized nanoparticles on charged lipid surfaces. The surface density of the particle monolayer can be tuned by changing the electrostatic interaction between the particles and the lipid surface. The in-situ measured particle desorption from the lipid surface due to a change of a salt concentration provides quantitative information on particle-surface interactions. The ex-situ studies on samples using XPS under similar conditions support our observations. Our studies explore the possibility to form regulated 2D systems, as well as provide basic understanding of interactions of charge nano-objects with lipids, which is important for the biomedical applications.

  17. 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

  18. Immunomodulatory spectrum of lipids associated with Mycobacterium avium serovar 8.

    PubMed Central

    Barrow, W W; Davis, T L; Wright, E L; Labrousse, V; Bachelet, M; Rastogi, N

    1995-01-01

    Lipid fractions obtained from Mycobacterium avium serovar 8 were assessed for the ability to affect various immune functions of human peripheral blood mononuclear cells (PBM). Lipids included a total lipid fraction and fractions eluted from silicic acid column separation of that total lipid fraction, using chloroform and chloroform-methanol combinations. Lipid fractions were assayed for total carbohydrate and total 6-deoxyhexose content and were assessed for the ability to influence human macrophage function and the capacity to induce secretion of prostaglandin E2 (PGE2) and tumor necrosis factor alpha in PBM. The total lipid and serovar-specific glycopeptidolipid (GPL) fractions both induced significant levels of tumor necrosis factor alpha, as well as PGE2, in PBM exposed to a sublethal concentration of 100 micrograms lipid per 2 x 10(6) cells. In addition, the same concentrations of the 5 to 7% and GPL fractions induced significant levels of leukotriene B4 in PBM. Comparison of carbohydrate and 6-deoxyhexose contents of each fraction suggested a relationship to carbohydrate content and ability of fractions to induce immune modulator secretion. Analysis of GPL fractions from M. avium serovars 4 and 20 revealed that those GPL lacked the ability to induce PGE2. These results are explained by considering the difference in the carbohydrate residues of the oligosaccharide moieties. PMID:7806348

  19. Diffusion and Partitioning of Fluorescent Lipid Probes in Phospholipid Monolayers

    PubMed Central

    Gudmand, M.; Fidorra, Matthias; Bjřrnholm, T.; Heimburg, T.

    2009-01-01

    The pressure-dependent diffusion and partitioning of single lipid fluorophores in DMPC and DPPC monolayers were investigated with the use of a custom-made monolayer trough mounted on a combined fluorescence correlation spectroscopy (FCS) and wide-field microscopy setup. It is shown that lipid diffusion, which is essential for the function of biological membranes, is heavily influenced by the lateral pressure and phase of the lipid structure. Both of these may change dynamically during, e.g., protein adsorption and desorption processes. Using FCS, we measured lipid diffusion coefficients over a wide range of lateral pressures in DMPC monolayers and fitted them to a free-area model as well as the direct experimental observable mean molecular area. FCS measurements on DPPC monolayers were also performed below the onset of the phase transition (? < 5 mN/m). At higher pressures, FCS was not applicable for measuring diffusion coefficients in DPPC monolayers. Single-molecule fluorescence microscopy and differential scanning calorimetry clearly showed that this was due to heterogeneous partitioning of the lipid fluorophores in condensed phases. The results were compared with dye partitioning in giant lipid vesicles. These findings are significant in relation to the application of lipid fluorophores to study diffusion in both model systems and biological systems. PMID:19486682

  20. Disruption of Synechocystis PCC 6803 for lipid extraction.

    PubMed

    Sheng, J; Vannela, R; Rittmann, B E

    2012-01-01

    In order to extract intracellular lipids from cyanobacterial Synechocystis PCC 6803 for biofuel production, seven cell-disruption methods - autoclaving, bead beating, freeze drying, French press, microwave, pulsed electric fields (PEF), and ultrasound - were tested prior to lipid extraction to make intracellular lipids more accessible by organic solvents. The different methods brought about distinct disruption effects to the cell envelope, plasma membrane, and thylakoid membranes that were related to extraction efficiency. Microwave, PEF, and ultrasound with temperature control had significant enhancement of lipid extraction (9-13% increases). Bead beating, freeze drying, and French press did not provide significant enhancement of lipid extraction. Furthermore, autoclaving, French press, and ultrasound treatments caused significant release of lipid into the medium, which may increase solvent usage and make medium recycling difficult. In order to minimize the cost of cell-disruption and lipid-extraction steps, microwave and PEF (with temperature control) might be best suited for large-scale cell disruption among all techniques investigated. PMID:22258690

  1. Mixed lipid bilayers with locally varying spontaneous curvature and bending.

    PubMed

    Gueguen, Guillaume; Destainville, Nicolas; Manghi, Manoel

    2014-08-01

    A model of lipid bilayers made of a mixture of two lipids with different average compositions on both leaflets, is developed. A Landau Hamiltonian describing the lipid-lipid interactions on each leaflet, with two lipidic fields ? 1 and ? 2, is coupled to a Helfrich one, accounting for the membrane elasticity, via both a local spontaneous curvature, which varies as C 0 + C 1(? 1 - ? 2/2), and a bending modulus equal to ? 0 + ? 1(? 1 + ? 2)/2. This model allows us to define curved patches as membrane domains where the asymmetry in composition, ? 1 - ? 2, is large, and thick and stiff patches where ? 1 + ? 2 is large. These thick patches are good candidates for being lipidic rafts, as observed in cell membranes, which are composed primarily of saturated lipids forming a liquid-ordered domain and are known to be thick and flat nano-domains. The lipid-lipid structure factors and correlation functions are computed for globally spherical membranes and planar ones and for a whole set of parameters including the surface tension and the coupling in the two leaflet compositions. Phase diagrams are established, within a Gaussian approximation, showing the occurrence of two types of Structure Disordered phases, with correlations between either curved or thick patches, and an Ordered phase, corresponding to the divergence of the structure factor at a finite wave vector. The varying bending modulus plays a central role for curved membranes, where the driving force ? 1 C 0 (2) is balanced by the line tension, to form raft domains of size ranging from 10 to 100 nm. For planar membranes, raft domains emerge via the cross-correlation with curved domains. A global picture emerges from curvature-induced mechanisms, described in the literature for planar membranes, to coupled curvature- and bending-induced mechanisms in curved membranes forming a closed vesicle. PMID:25160487

  2. Interplay between hydration water and headgroup dynamics in lipid bilayers.

    PubMed

    Berntsen, P; Svanberg, C; Swenson, J

    2011-03-01

    In this study, the interplay between water and lipid dynamics has been investigated by broadband dielectric spectroscopy and modulated differential scanning calorimetry (MDSC). The multilamellar lipid bilayer system 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) has been studied over a broad temperature range at three different water contents: about 3, 6, and 9 water molecules per lipid molecule. The results from the dielectric relaxation measurements show that at temperatures <250 K the lipid headgroup rotation is described by a super-Arrhenius temperature dependence at the lowest hydration level and by the Arrhenius law at the highest hydration level. This difference in the temperature dependence of the lipid headgroup rotation can be explained by the increasing interaction between the headgroups with decreasing water content, which causes their rotational motion to be more cooperative in character. The main water relaxation shows an anomalous dependence on the water content in the supercooled and glassy regime. In contrast to the general behavior of interfacial water, the water dynamics is fastest in the driest sample and its temperature dependence is best described by a super-Arrhenius temperature dependence. The best explanation for this anomalous behavior is that the water relaxation becomes more determined by fast local lipid motions than by the intrinsic water dynamics at low water contents. In support for this interpretation is the finding that the relaxation time of the main water process is faster than that in most other host systems at temperatures below 180 K. Thus, the dielectric relaxation data show clearly the strong interplay between water and lipid dynamics; the water influences the lipid dynamics and vice versa. In the MDSC data, we observe a weak enthalpy relaxation at 203 K for the driest sample and at 179 K for the most hydrated sample, attributed to the freezing-in of the lipid headgroup rotation observed in the dielectric data, since this motion reaches a time scale of about 100 s at about the same temperatures. PMID:21302948

  3. Low Primary Lipid Screening among Medicare Patients with Rheumatoid Arthritis

    PubMed Central

    Bartels, Christie M; Kind, Amy JH; Everett, Christine; Mell, Matthew; McBride, Patrick; Smith, Maureen

    2011-01-01

    Objective Although reports demonstrate suboptimal preventive cancer screening in RA patients, primary lipid screening performance has not been systematically examined. We examined associations between primary lipid screening and visits to primary care providers (PCPs) and rheumatologists among a national sample of older RA patients. Methods This retrospective cohort study examines a 5% Medicare sample including 3,298 RA patients without baseline cardiovascular disease (CVD), diabetes, or hyperlipidemia, that were considered eligible for primary lipid screening (2004–2006). The outcome was probability of lipid screening by the relative frequency of primary care and rheumatology visits, or seeing a PCP at least once each year. Results Primary lipid screening was performed in only 45% of RA patients. Overall, 65% received both primary and rheumatology care, and half saw a rheumatologist as often as a PCP. Any primary care predicted more lipid screening than lone rheumatology (26%, 95% CI=21, 32). As long as a PCP was involved, lipid screening performance was similar regardless of the balance between primary and rheumatology visits, (44–48%, CI=41–51). Not seeing a PCP at least annually decreased screening 22% (adjusted risk ratio [ARR]=0.78, 0.71, 0.84). Conclusion Primary lipid screening was performed in fewer than half of eligible RA patients, highlighting a key target for CVD risk reduction efforts. Annual PCP visits improved lipid screening, though performance remained poor (51%). Half of RA patients saw their rheumatologist as often, or more often, than a PCP, illustrating the need to study optimal partnerships between primary care and rheumatologists for screening CVD risks. PMID:21305507

  4. Solid Lipid Nanoparticles as Delivery Systems for Bromocriptine

    Microsoft Academic Search

    Elisabetta Esposito; Martina Fantin; Matteo Marti; Markus Drechsler; Lydia Paccamiccio; Paolo Mariani; Elisa Sivieri; Francesco Lain; Enea Menegatti; Michele Morari; Rita Cortesi

    2008-01-01

    Purpose  The present investigation describes a formulative study for the development of innovative drug delivery systems for bromocriptine.\\u000a \\u000a \\u000a \\u000a Methods  Solid lipid nanoparticles (SLN) based on different lipidic components have been produced and characterized. Morphology and\\u000a dimensional distribution have been investigated by electron microscopy and Photon Correlation Spectroscopy. The antiparkinsonian\\u000a activities of free bromocriptine and bromocriptine encapsulated in nanostructured lipid carriers were evaluated

  5. Two-dimensional crystallization of avidin on biotinylated lipid monolayers.

    PubMed Central

    Qin, H; Liu, Z; Sui, S F

    1995-01-01

    Two-dimensional crystals of avidin were obtained on mixed lipid monolayers containing biotinylated lipids (N-biotinyl-dipalmitoyl-L-alpha-phosphatidyl ethanolamine and dioleoyl phosphatidyl choline) by specific interaction. Image analysis of electron micrographs of these crystals revealed p2 symmetry with the unit cell parameters a = 66 +/- 2 A, b = 68 +/- 1 A, and gamma = 121 +/- 4 degrees. The projection map showed, at a resolution of about 27 A, that the four subunits within one avidin molecule are separated into two parts. Comparison between avidin and streptavidin reveals that avidin molecule binds to the lipid monolayer in an orientation similar to that of streptavidin. Images FIGURE 2 FIGURE 3 PMID:7647251

  6. Nuclear Receptors and Lipid Physiology: Opening the X-Files

    NSDL National Science Digital Library

    Ajay Chawla (The Salk Institute for Biological Studies; Howard Hughes Medical Institute, Gene Expression Laboratory)

    2001-11-30

    Cholesterol, fatty acids, fat-soluble vitamins, and other lipids present in our diets are not only nutritionally important but serve as precursors for ligands that bind to receptors in the nucleus. Specifically, what is the nature of communication between these bioactive lipids and their receptors, binding proteins, transporters, and metabolizing enzymes that links them physiologically and speaks to a higher level of metabolic control? Some general principles that govern the actions of this class of bioactive lipids and their nuclear receptors are considered here, and the scheme that emerges reveals a complex molecular script at work.

  7. 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.

  8. 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. (Liposome Company, Inc., Princeton, NJ (USA))

    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.

  9. Characterization of the transverse relaxation rates in lipid bilayers

    SciTech Connect

    Watnick, P.I.; Dea, P.; Chan, S.I. (California Institute of Technology, Pasadena (USA))

    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.

  10. 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

  11. 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

  12. Alteration of cellular lipids and lipid metabolism markers in RTL-W1 cells exposed to model endocrine disrupters.

    PubMed

    Dimastrogiovanni, Giorgio; Córdoba, Marlon; Navarro, Isabel; Jáuregui, Olga; Porte, Cinta

    2015-08-01

    This work investigates the suitability of the rainbow trout liver cell line (RTL-W1) as an in-vitro model to study the ability of model endocrine disrupters, namely TBT, TPT, 4-NP, BPA and DEHP, to act as metabolic disrupters by altering cellular lipids and markers of lipid metabolism. Among the tested compounds, BPA and DEHP significantly increased the intracellular accumulation of triacylglycerols (TAGs), while all the compounds -apart from TPT-, altered membrane lipids - phosphatidylcholines (PCs) and plasmalogen PCs - indicating a strong interaction of the toxicants with cell membranes and cell signaling. RTL-W1 expressed a number of genes involved in lipid metabolism that were modulated by exposure to BPA, TBT and TPT (up-regulation of FATP1 and FAS) and 4-NP and DEHP (down-regulation of FAS and LPL). Multiple and complex modes of action of these chemicals were observed in RTL-W1 cells, both in terms of expression of genes related to lipid metabolism and alteration of cellular lipids. Although further characterization is needed, this might be a useful model for the detection of chemicals leading to steatosis or other diseases associated with lipid metabolism in fish. PMID:26143618

  13. Influence of Polyethylene Glycol Lipid Desorption Rates on Pharmacokinetics and Pharmacodynamics of siRNA Lipid Nanoparticles

    PubMed Central

    Mui, Barbara L; Tam, Ying K; Jayaraman, Muthusamy; Ansell, Steven M; Du, Xinyao; Tam, Yuen Yi C; Lin, Paulo JC; Chen, Sam; Narayanannair, Jayaprakash K; Rajeev, Kallanthottathil G; Manoharan, Muthiah; Akinc, Akin; Maier, Martin A; Cullis, Pieter; Madden, Thomas D; Hope, Michael J

    2013-01-01

    Lipid nanoparticles (LNPs) encapsulating short interfering RNAs that target hepatic genes are advancing through clinical trials, and early results indicate the excellent gene silencing observed in rodents and nonhuman primates also translates to humans. This success has motivated research to identify ways to further advance this delivery platform. Here, we characterize the polyethylene glycol lipid (PEG-lipid) components, which are required to control the self-assembly process during formation of lipid particles, but can negatively affect delivery to hepatocytes and hepatic gene silencing in vivo. The rate of transfer from LNPs to plasma lipoproteins in vivo is measured for three PEG-lipids with dialkyl chains 14, 16, and 18 carbons long. We show that 1.5?mol % PEG-lipid represents a threshold concentration at which the chain length exerts a minimal effect on hepatic gene silencing but can still modify LNPs pharmacokinetics and biodistribution. Increasing the concentration to 2.5 and 3.5?mol % substantially compromises hepatocyte gene knockdown for PEG-lipids with distearyl (C18) chains but has little impact for shorter dimyristyl (C14) chains. These data are discussed with respect to RNA delivery and the different rates at which the steric barrier disassociates from LNPs in vivo. PMID:24345865

  14. Unbiased quantitative proteomics of lipid rafts reveals high specificity for signaling factors

    Microsoft Academic Search

    Leonard J. Foster; Carmen L. de Hoog; Matthias Mann

    2003-01-01

    Membrane lipids were once thought to be homogenously distributed in the 2D surface of a membrane, but the lipid raft theory suggests that cholesterol and sphingolipids partition away from other membrane lipids. Lipid raft theory further implicates these cholesterol-rich domains in many processes such as signaling and vesicle traffic. However, direct characterization of rafts has been difficult, because they cannot

  15. Detergent-resistant membranes and the protein composition of lipid rafts

    PubMed Central

    Magee, Anthony I; Parmryd, Ingela

    2003-01-01

    The plasma membrane of eukaryotic cells contains lipid rafts with protein and lipid compositions differing from the bulk plasma membrane. Several recent proteomic studies have addressed the composition of lipid rafts, but the different definitions used for lipid rafts need scrutinizing before results can be evaluated. PMID:14611651

  16. Physicochemical characterization of lipid nanoparticles and evaluation of their drug loading capacity and sustained release potential

    Microsoft Academic Search

    K Westesen; H Bunjes; M. H. J Koch

    1997-01-01

    Drug carrier systems based on lipid nanosuspensions prepared by melt emulsification present a number of severe stability problems such as a high gelation tendency, considerable particle growth and drug expulsion. Destabilization of the emulsified lipidic carriers is related to recrystallization of the lipids. The choice of stabilizers for colloidal lipid suspensions is, therefore, restricted. Systematic surface modifications are thus limited.

  17. Cationic Nucleoside Lipids Derived from Universal Bases: A Rational Approach for siRNA Transfection

    E-print Network

    functionality based on the combination of nucleic acids and lipid characteristics (1-4). Nucleoside lipidsCationic Nucleoside Lipids Derived from Universal Bases: A Rational Approach for siRNA Transfection lipids (CNLs) derived from 5-nitroindole and 4-nitroimidazole bases were prepared from D-ribose by using

  18. Dissociation between cholesterol secretion and plasma lipid transfer activity in rabbits

    Microsoft Academic Search

    DAVID W. QUIG; DONALD B. ZILVERSMIT

    Human and rabbit plasma contains a lipid transfer protein that transfers cholesteryl esters and triglycerides among the plasma lipoproteins and may also have a role in the movement of lipids into and out of cells. Little is known about the regulation of the activity of the lipid transfer protein, but in the rabbit, hypercholesterolemia is associated with increased plasma lipid

  19. Lipid transport mediated by Arabidopsis TGD proteins is unidirectional from the endoplasmic reticulum to the plastid

    Microsoft Academic Search

    C. Xu; E. R. Moellering; B. Muthan; J. Fan; C. Benning

    2010-01-01

    The transfer of lipids between the endoplasmic reticulum (ER) and the plastid in Arabidopsis involves the TRIGALACTOSYLDIACYLGLYCEROL (TGD) proteins. Lipid exchange is thought to be bidirectional based on the presence of specific lipid molecular species in Arabidopsis mutants impaired in the desaturation of fatty acids of membrane lipids in the ER and plastid. However, it was unclear whether TGD proteins

  20. Changes of lipid, protein, RNA and fatty acid composition in developing sesame ( Sesamum indicum L.) seeds

    Microsoft Academic Search

    Chung H. Chung; Young J. Yee; Doh H. Kim; Hyoun K. Kim; Dae S. Chung

    1995-01-01

    During development of sesame oilseeds, changes in lipid, protein and RNA levels were scrutinized and discussed. In total lipid a rapid increase commenced at 15 days after flowering (DAF) and continued to 38 DAF. Thereafter a gradual rise was found and finally the lipid accumulated as storage lipid. In changes of protein a sudden increase was observed at 12 DAF,