Note: This page contains sample records for the topic sleep-inducing lipid oleamide from
While these samples are representative of the content of,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of
to obtain the most current and comprehensive results.
Last update: November 12, 2013.

The Sleep-inducing Lipid Oleamide Deconvolutes Gap Junction Communication and Calcium Wave Transmission in Glial Cells  

PubMed Central

Oleamide is a sleep-inducing lipid originally isolated from the cerebrospinal fluid of sleep-deprived cats. Oleamide was found to potently and selectively inactivate gap junction–mediated communication between rat glial cells. In contrast, oleamide had no effect on mechanically stimulated calcium wave transmission in this same cell type. Other chemical compounds traditionally used as inhibitors of gap junctional communication, like heptanol and 18?-glycyrrhetinic acid, blocked not only gap junctional communication but also intercellular calcium signaling. Given the central role for intercellular small molecule and electrical signaling in central nervous system function, oleamide- induced inactivation of glial cell gap junction channels may serve to regulate communication between brain cells, and in doing so, may influence higher order neuronal events like sleep induction.

Guan, Xiaojun; Cravatt, Benjamin F.; Ehring, George R.; Hall, James E.; Boger, Dale L.; Lerner, Richard A.; Gilula, Norton B.



The sleep inducing brain lipid cis-oleamide (cOA) does not modulate serotonergic transmission in the CA1 pyramidal neurons of the hippocampus in vitro  

Microsoft Academic Search

cis-Oleamide (cOA) is a novel sleep inducing brain lipid with an unknown mechanism of action. High affinity interactions with metabotropic 5-HT receptors (2A\\/C and 1A subtypes) in frog oocytes and expression systems have been reported, but functional in vitro evidence for the modulatory effect is still lacking. Here, we addressed the ability of cOA to modulate 5-HT-induced cellular actions in

Antonios Dougalis; George Lees; C. Robin Ganellin



The sleep inducing factor oleamide is produced by mouse neuroblastoma cells.  


Cis-9,10-octadecenoamide (oleamide) was isolated from the cerebrospinal fluid of sleep-deprived mammals and shown to induce sleep in rats. The enzyme catalyzing the hydrolysis of the amide bond of oleamide as well as of anandamide, the putative endogenous ligand of cannabinoid receptors, was purified from rat liver, cloned, shown to be expressed also in brain and named fatty acid amide hydrolase (FAAH). The enzymatic synthesis of oleamide from oleic acid and ammonia by rat brain microsomes has been also described. However, no evidence has been reported so far on the neuronal origin of oleamide, necessary in order to postulate for this compound a role as a neuromodulator. Here we show for the first time that oleamide is produced by a neuronal cell type and that its biosynthesis in intact neurons is not likely to occur through the direct condensation of oleic acid and ammonia. A lipid metabolite was extracted and purified from mouse neuroblastoma N18TG2 cells through a sequence of chromatographic steps and characterized as oleamide by means of gas chromatography/electron impact mass spectrometry (GC/EIMS). The amount of oleamide, as estimated by GC analyses carried out in comparison with known amounts of synthetic oleamide, was 55.0+/-09.5 pmols/10(7) cells, compared to less than 0.7 pmol/10(7) cells for anandamide in the same cells. When N18TG2 cells were prelabeled with [14C]oleic acid and the lipids extracted and purified, a radioactive component with the same chromatographic behavior as oleamide was found whose levels: (1) were not significantly influenced by stimulation with ionomycin; (2) were slightly increased by incubation with FAAH inhibitor phenyl-methyl-sulphonyl-fluoride (PMSF); (3) appeared to correlate with [14C]oleic acid incorporation into phospholipids but not with free [14C]oleic acid levels. N18TG2 cell membranes were shown to contain an enzymatic activity catalyzing the synthesis of oleamide from oleic acid and ammonia. This activity was inhibited by FAAH selective inhibitors arachidonoyltrifluoromethylketone and methylarachidonoylfluorophosphonate, as well as by an excess of anandamide, and by PMSF at the same concentration which increased oleamide formation in intact cells. These data suggest that a FAAH-like enzyme working "in reverse" may be responsible for the formation of oleamide in cell-free preparations but not in whole cells. PMID:9344854

Bisogno, T; Sepe, N; De Petrocellis, L; Mechoulam, R; Di Marzo, V



A gas chromatographic-mass spectral assay for the quantitative determination of oleamide in biological fluids.  


Oleamide is a putative endogenous sleep-inducing lipid which potently enhances currents mediated by GABAA and serotonin receptors. While a quantitative assay would aid in determining the role of oleamide in physiological processes, most of the available assays are lacking in sensitivity. We now describe a quantitative assay for measuring low nanogram amounts of oleamide in biological fluids using GC/MS in the selective ion-monitoring mode. The internal standard (13C18 oleamide) was added to known concentrations of oleamide, which were converted to the N-trimethylsilyl or N-tert-butyldimethylsilyl derivatives before analysis by GC/MS, yielding linear calibration curves over the range of 1-25 ng of oleamide when monitoring the m/z 338/356 fragments. Using this technique, oleamide levels were determined following solvent extraction of normal rat cerebrospinal fluid and plasma to be 44 and 9.9 ng/ml, respectively. This technique constitutes a sensitive and reliable method for determining low nanogram quantities of oleamide in biological fluids. PMID:10328778

Hanus, L O; Fales, H M; Spande, T F; Basile, A S



One-step formation of straight nanostripes from a mammal lipid-oleamide directly on highly oriented pyrolytic graphite.  


Hierarchical nanostructures are obtained directly on highly oriented pyrolytic graphite (HOPG) by spin coating of dilute chloroform solution of 9-Z-octadecenamide (oleamide), a natural lipid with cis-CdC- conformation, existing in the cerebrospinal fluid of mammal animals and being an additive for medical use and food packaging. Straight separated nanostripes with a length of 70-300 nm exist in the topmost layer and compact nanostripes in the bottom layer contacting HOPG. Compact nanostripes have a periodicity spacing of 3.8 nm, indicating H-bonding between two rows of oleamide molecules. The orientation of the hierarchical nanostructures differs by n60 degrees+/-8 degrees (n=1 or 2), reflecting the epitaxial ordering along theHOPGsubstrate. The nanostripes are stable against annealing.Amolecular packing scheme for the nanostructures is proposed, where the -C=C bond angle in oleamide is 120 degrees and the plane of the carbon skeleton lies parallel to the HOPG substrate. Nanostripes in the topmost layer are formed from separated rows of oleamide molecules, due to the short-range surface potential of the substrate. The scheme involves direct influence ofHOPGon the orientation of oleamide molecules to form nanostripes without any purposely added saturated alkanes and H-bonds between amide groups in adjacent two rows of oleamide molecules. PMID:19125608

Zhang, Renjie; Möhwald, Helmuth; Kurth, Dirk G



Effect of oleamide on Ca 2+ signaling in human bladder cancer cells 1 1 Abbreviations: ATP, adenosine 5?-triphosphate; [Ca 2+] i, intracellular free Ca 2+ concentration; fura-2\\/AM, 1-[2-(5-carboxyoxazol-2-yl)-6-aminobenzofuran-5-oxy]-2-(2?-amino-5?-methylphenoxy)-ethane-N,N,N,N-tetraacetic acid pentaacetoxymethyl ester; SKF96365, 1-[?-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride; U73122, 1-(6-((17?-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; U73343, and 1-(6-((17?-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-2,5-pyrrolidine-dione  

Microsoft Academic Search

The effect of oleamide, a sleep-inducing endogenous lipid in animal models, on intracellular free levels of Ca2+ ([Ca2+]i) in non-excitable and excitable cells was examined by using fura-2 as a fluorescent dye. [Ca2+]i in pheochromocytoma cells, renal tubular cells, osteoblast-like cells, and bladder cancer cells were increased on stimulation of 50 ?M oleamide. The response in human bladder cancer cells

Yuk-Keung Lo; Kwong-Yui Tang; Wen-Neng Chang; Cheng-Hsien Lu; Jin-Shiung Cheng; Kam-Chung Lee; Kang-Ju Chou; Chun-Peng Liu; Wei-Chung Chen; Warren Su; Yee-Ping Law; Chung-Ren Jan



In Vivo Evidence that N-Oleoylglycine Acts Independently of Its Conversion to Oleamide  

PubMed Central

Oleamide (cis-9-octadecenamide) is a member of an emerging class of lipid-signaling molecules, the primary fatty acid amides. A growing body of evidence indicates that oleamide mediates fundamental neurochemical processes including sleep, thermoregulation, and nociception. Nevertheless, the mechanism for oleamide biosynthesis remains unknown. The leading hypothesis holds that oleamide is synthesized from oleoylglycine via the actions of the peptide amidating enzyme, peptidylglycine alpha amidating monooxygenase (PAM). The present study investigated this hypothesis using pharmacologic treatments, physiologic assessments, and measurements of serum oleamide levels using a newly development enzyme-linked immunosorbant assay (ELISA). Oleamide and oleoylglycine both induced profound hypothermia and decreased locomotion, over equivalent dose ranges and time courses, whereas, closely related compounds, stearamide and oleic acid, were essentially without effect. While the biologic actions of oleamide and oleoylglycine were equivalent, the two compounds differed dramatically with respect to their effects on serum levels of oleamide. Oleamide administration (80 mg/kg) elevated blood-borne oleamide by eight-fold, whereas, the same dose of oleoylglycine had no effect on circulating oleamide levels. In addition, pretreatment with the established PAM inhibitor, disulfiram, produced modest reductions in the hypothermic responses to both oleoylglycine and oleamide, suggesting that the effects of disulfiram were not mediated through inhibition of PAM and a resulting decrease in the formation of oleamide from oleoylglycine. Collectively, these findings raise the possibilities that: (1) oleoylglycine possesses biologic activity that is independent of its conversion to oleamide, and (2) the increased availability of oleoylglycine as a potential substrate does not drive the biosynthesis of oleamide.

Chaturvedi, Shalini; Driscoll, William J.; Elliot, Brenda M.; Faraday, Martha M.; Grunberg, Neil E.; Mueller, Gregory P.



Unique Allosteric Regulation of 5-hydroxytryptamine Receptor-Mediated Signal Transduction by Oleamide  

Microsoft Academic Search

The effects of oleamide, an amidated lipid isolated from the cerebrospinal fluid of sleep-deprived cats, on serotonin receptor-mediated responses were investigated in cultured mammalian cells. In rat P11 cells, which endogenously express the 5-hydroxytryptamine2A (5HT2A) receptor, oleamide significantly potentiated 5HT-induced phosphoinositide hydrolysis. In HeLa cells expressing the 5HT7 receptor subtype, oleamide caused a concentration-dependent increase in cAMP accumulation but with

Elizabeth A. Thomas; Monica J. Carson; Michael J. Neal; J. Gregor Sutcliffe



Mechanisms involved in oleamide-induced vasorelaxation in rat mesenteric resistance arteries  

PubMed Central

Fatty acid amides are a new class of signaling lipids that have been implicated in diverse physiological and pathological conditions. Oleamide is a fatty acid amide that induces vasorelaxation. Here, we investigated the mechanisms behind the vasorelaxation effect of oleamide in rat mesenteric resistance arteries. Oleamide-induced concentration dependent (0.01 ?M–10?M) vasorelaxation in mesenteric resistance arteries. This relaxation was unaffected by the presence of the fatty acid amide hydrolase (FAAH) inhibitors. The cannabinoid type 1 (CB1) receptor antagonist, AM251 and the non-CB1/CB2 cannabinoid receptor antagonist, O-1918, attenuated the oleamide vasodilatory response, however the cannabinoid CB2 receptor antagonist, AM630, did not affect the vascular response. Moreover, inhibition of the transient receptor potential vanilloid (TRPV) 1 receptor with capsazepine shifted the oleamide-induced vasorelaxation response to the right. In agreement with the vascular functional data, the cannabinoid CB1 and TRPV1 receptor proteins were expressed in mesenteric resistance arteries but cannabinoid CB2 receptors and the FAAH enzyme were not. In endothelium-denuded arteries, the oleamide-mediated vasorelaxation was attenuated and cannabinoid CB1 or non-CB1/CB2 cannabinoid receptor blockade did not further reduce the dilatory response whereas TRPV1 antagonism further decreased the response. These findings indicate that cannabinoid receptors on the endothelium and endothelium-independent TRPV1 receptors contribute to the oleamide vasodilatory response. Taken together, these results demonstrate that the oleamide-induced vasorelaxation is mediated, in part, by cannabinoid CB1 receptors, non-CB1/CB2 cannabinoid receptors, and TRPV1 receptors in rat mesenteric resistance arteries. These mechanisms are overlapping in respect to oleamide-induced mesenteric resistance artery dilation.

Sudhahar, Varadarajan; Shaw, Sean; Imig, John D.



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

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,

Christopher J Fowler; Kent-Olov Jonsson; Gunnar Tiger



Enhanced radiosensitization of p53 mutant cells by oleamide  

SciTech Connect

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.

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:



Fatty Acid Composition of Milk from Holstein Cows Fed Oleamide or Canola Oil1  

Microsoft Academic Search

Based on previous in vitro results that showed reduced biohydrogenation of oleamide by ruminal mi- crobes, this study was conducted to determine whether the addition of oleamide to the diets of dairy cows would enhance the C18:1 concentration in milk. Nine first lactation Holstein cows were fed three diets in a 3 × 3 Latin square replicated three times. Each

T. C. Jenkins



Lactation Performance and Fatty Acid Composition of Milk from Holstein Cows Fed 0 to 5% Oleamide1  

Microsoft Academic Search

Diets containing 0 to 5% oleamide were fed to Holstein cows to determine linear or nonlinear responses to the fat supplement on lactation perfor- mance and milk fatty acid composition. Six rations containing concentrate, corn silage, and 0, 1, 2, 3, 4, or 5% (dry matter basis) added oleamide were fed to six multiparous cows in a 6 × 6

T. C. Jenkins



Block of erg current by linoleoylamide, a sleep-inducing agent, in pituitary GH3 cells.  


Linoleoylamide is physiological constituent of neurons. The effects of this agent, also a sleep-inducing agent, on ion currents in pituitary GH(3) cells were investigated. Hyperpolarization-elicited K(+) currents in GH(3) cells bathed in a high-K(+), Ca(2+)-free solution were studied to determine the effects of linoleoylamide and other related compounds on the I(K(IR)) that was sensitive to inhibition by E-4031 and identified as an erg (ether-à-go-go-related-gene) current. Linoleoylamide suppressed the amplitude of I(K(IR)) in a concentration-dependent manner with an IC(50) value of 5 microM. Oleamide (20 microM) inhibited the amplitude of I(K(IR)), while neither arachidonic acid (20 microM) nor 14,15-epoxyeicosatrienoic acid (20 microM) had an effect on it. In GH(3) cells incubated with anandamide (20 microM) or arachidonic acid (20 microM), the linoleoylamide-induced inhibition of I(K(IR)) remained unaltered. In inside-out patches, arachidonic acid (20 microM) and 14,15-epoxyeicosatrienoic acid (20 microM) stimulated large-conductance Ca(2+)-activated K(+) channels; however, linoleoylamide (20 microM) had little or no effect on them. Under current-clamp mode, linoleoylamide (20 microM) increased the firing rate. In IMR-32 neuroblastoma cells, linoleoylamide also suppressed I(K(IR)). This study provides the evidence that linoleoylamide has a depressant effect on the erg current, and suggests that this effect may affect hormonal secretion. PMID:12498905

Liu, Yen Chin; Wu, Sheng Nan



Vasorelaxant effects of oleamide in rat small mesenteric artery indicate action at a novel cannabinoid receptor  

PubMed Central

Oleamide (cis-9-octadecenoamide) exhibits some cannabimimetic responses despite its low affinities at the currently known cannabinoid receptors. Here we have investigated whether or not it is a vasorelaxant in rat small mesenteric arteries. Oleamide elicited vasorelaxation (EC50=1.2±0.2??M, Rmax=99.1±3.9%, n=8) which was reduced by endothelial removal. Nitric oxide synthase inhibition reduced the response (EC50=5.3±1.6??M, Rmax=59.2±7.7%, n=7; P<0.01) as did blockade of Ca2+-sensitive K+ channels (KCa) with apamin plus charybdotoxin (both 50?nM) (EC50=2.1±0.2??M, Rmax=58.4±1.9%, n=5; P<0.05). Desensitisation of vanilloid receptors with capsaicin (10??M for 30?min) shifted the oleamide concentration–response curve ?30-fold to the right (n=7; P<0.01). Pertussis toxin (400?ng?ml?1 for 2?h) caused a two-fold shift in the response curve (EC50=2.2±0.4??M, Rmax=66.8±4.5%, n=6; P<0.01). Rimonabant (CB1 cannabinoid receptor antagonist; SR141716A; 3??M) significantly inhibited relaxation induced by oleamide (EC50=3.5±0.3??M, Rmax=75.1±1.9%; n=8; P<0.05). In contrast, neither the more selective CB1 receptor antagonist, AM251 (1??M), nor the CB2 antagonist, SR144528 (1??M), had significant effects. O-1918 (10??M), a putative antagonist at a novel endothelial cannabinoid receptor (abnormal-cannabidiol site), markedly reduced the relaxation to oleamide (n=7; P<0.01). It is concluded that oleamide responses in the rat isolated small mesenteric artery are partly dependent on the presence of the endothelium, activation of Ca2+-sensitive K+ channels (KCa) and involve capsaicin-sensitive sensory nerves. Oleamide may share a receptor (sensitive to rimonabant and O-1918, and coupled to KCa and Gi/o) with anandamide in this vessel. This might be distinct from both of the known cannabinoid receptors and the novel abnormal-cannabidiol site.

Hoi, Pui Man; Hiley, C Robin



Sleep-Inducing Substances in the Regulation of Sleep  

Microsoft Academic Search

\\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

Vijay Ramesh; Navita Kaushal; Velayudhan Mohan Kumar


Oleamide restores sleep in adult rats that were subjected to maternal separation.  


Maternal separation (MS) induces a series of changes in rats' behavior; among them a reduction in spontaneous sleep. One potentially impaired system is the endocannabinoid system (eCBs), since it contributes to generate sleep. To investigate if there are situations early in life that affect the eCBs, which would contribute to make rats vulnerable to suffering insomnia, we studied the rodent model of MS. Rats were separated from their mothers for 3h-periods daily, from postnatal day (PND) 2 to PND 16. Once they gained 250g of body weight (adult rats), they were implanted with electrodes to record the sleep-waking cycle (SWC). MS rats and non-MS (NMS) siblings were assigned to one of the following groups: vehicle, oleamide (OLE, an agonist of the cannabinoid receptor 1, CB1R), OLE+AM251 (an antagonist of the CB1R) and AM251 alone. Expression of the CBR1 receptor was also analyzed in the frontal cortex (FCx) and in the hippocampus (HIP) of both NMS and MS rats. Results indicated that MS induced a reduction in both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep with the consequent increase in waking (W) as compared to NMS siblings. OLE normalized the SWC, and AM251 blocked such an effect. CB1R expression was reduced in the FCx and in the HIP of MS rats. Our results indicate that MS reduces sleep and CB1R expression and OLE improves sleep in adult rats. PMID:22975223

Reyes Prieto, Nidia M; Romano López, Antonio; Pérez Morales, Marcel; Pech, Olivia; Méndez-Díaz, Mónica; Ruiz Contreras, Alejandra E; Prospéro-García, Oscar



Rapid Communication Fatty Acid Amide Hydrolase, the Degradative Enzyme for Anandamide and Oleamide, Has Selective Distribution in Neurons Within the Rat Central Nervous System  

Microsoft Academic Search

Fatty acid amide hydrolase (FAAH) is a membrane- bound enzyme activity that degrades neuromodula- tory fatty acid amides, including oleamide and anan- damide. A single 2.5-kb FAAH mRNA is distributed throughout the rat CNS and accumulates progres- sively between embryonic day 14 and postnatal day 10, remains high until postnatal day 30, then decreases into adulthood. FAAH enzymatic activity, as

Elizabeth A. Thomas; Benjamin F. Cravatt; Patria E. Danielson; Norton B. Gilula


Multivariate and Psycho-Physiological Functions of DSIP (Delta-Sleep-Inducing Peptide),  

National Technical Information Service (NTIS)

Delta-Sleep-Inducing-Peptide (DSIP) beside humoral sleep induction acts upon the circadian rhythmicity of the locomotor activity and transmitter concentrations in the brain as well as on that of plasma proteins and cortisol levels in rats. It influences t...

G. A. Schoenenberger A. Ernst D. Schneider-Helmert




NSDL National Science Digital Library

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.

Reich, Ieva



[The role of the delta sleep-inducing peptide in the formation of neuropathological syndromes].  


The authors considered the pathogenetic role of delta-sleep inducing peptide (DSIP) in different neuropathological syndromes development and manifestation. According to own as well as published in the literature data authors showed the parkinsonian and the rotational syndromes development following DSIP central administration. Briefly, DSIP is a neuropeptide which play significant role in the mechanisms of development of different neuropathological syndromes, namely, epileptic, parkinsonian, withdrawal, rotational and others syndromes. PMID:8581045

Shandra, A A; Godlevski?, L S; Vast'ianov, R S; Brusentsov, A I; Moalla, I; Nikel', B



Effects of delta-sleep-inducing peptide in cerebral ischemia in rats  

Microsoft Academic Search

Experimental studies were carried out to investigate the neuroprotective effects of delta-sleep-inducing peptide in animals\\u000a with cerebral ischemia induced by bilateral compression of both carotid arteries, and to compare the efficacy of this peptide\\u000a with that of MK-801. These studies led to the conclusion that the peptide had pronounced anti-ischemic effects, which were\\u000a evident within 24 h and consisted of

A. A. Shandra; L. S. Godlevskii; A. I. Brusentsov; R. S. Vast’yanov; V. A. Karlyuga; A. F. Dzygal; B. Nikel



Model-Based Analysis of Mechanisms Responsible for Sleep-Induced Carbon Dioxide Differences  

Microsoft Academic Search

This work describes a comprehensive mathematical model of the human respiratory control system which incorporates the central\\u000a mechanisms for predicting sleep-induced changes in chemical regulation of ventilation. The model integrates four individual\\u000a compartments for gas storage and exchange, namely alveolar air, pulmonary blood, tissue capillary blood, body tissues, and\\u000a gas transport between them. An essential mechanism in the carbon dioxide

T. Aittokallio; M. Gyllenberg; O. Polo; J. Toivonen; A. Virkki



The H1 histamine receptor blocker, chlorpheniramine, completely prevents the increase in REM sleep induced by immobilization stress in rats  

Microsoft Academic Search

Chlorpheniramine is a selective antagonist of the H1 histaminergic receptor subtype and its effects in humans include somnolence. Chlorpheniramine affects sleep in rats, mainly by decreasing REM sleep. On the other hand, stress by immobilization induces an important increase in the percentage of REM sleep. In this study we analyzed the effects of blocking histaminergic receptors on REM sleep induced

J. A. Rojas-Zamorano; E. Esqueda-Leon; A. Jimenez-Anguiano; L. Cintra-McGlone; M. A. Mendoza Melendez; J. Velazquez Moctezuma



Antidepressant properties of antibodies to serotonin, brain-specific S100 protein, and delta sleep-inducing peptide.  


Potentiated antibodies to delta sleep-inducing peptide and S100 protein produced an antidepressant effect in Wistar rats. This effect was more pronounced after combined treatment with these antibodies. It can be assumed that these antibodies modulate neurobiological mechanisms of positive emotional reinforcement and, therefore, affect the resistance to depression associated with psychoemotional stress. PMID:12949638

Meshcheryakov, A F



Effects of delta-sleep-inducing peptide in cerebral ischemia in rats.  


Experimental studies were carried out to investigate the neuroprotective effects of delta sleep-inducing peptide in animals with cerebral ischemia induced by bilateral compression of both carotid arteries, and to compare the efficacy of this peptide with that of MK-801. These studies led to the conclusion that the peptide had pronounced anti-ischemic effects, which were evident within 24 h and consisted of reductions in the severity of postural abnormalities in rats with bilateral cerebral ischemia, along with a reduction in lethality. Comparison of the efficacies of peptide and MK-801 showed the peptide to have the greater neuroprotective effect. These results are regarded as providing an experimental basis for using the peptide as a therapeutic agent in patients with stroke. PMID:9762721

Shandra, A A; Godlevskii, L S; Brusentsov, A I; Vast'yanov, R S; Karlyuga, V A; Dzygal, A F; Nikel, B


[Effects of beta endorphin and delta-sleep inducing peptide on resistance to emotional stress].  


Enzyme immunoassay was used to study the contents of beta-endorphin and delta-sleep inducing peptide (DSIP) in blood and hypothalamus in rats of Wistar and August lines under acute emotional stress. The stress-resistance of the animals was determined by using preliminary behavior tests. The rats were divided into two groups and predisposed to acute emotional stress. It was found that the contents of these peptides in Wistar-rats, which are more resistant to emotional stress, were higher compared with the August-rats, which are more predisposed to emotional stress. It was shown that the contents of beta-endorphin and DSIP in Wistar-rats is higher than in predisposed Wistar-rats. PMID:2532045

Salieva, R M; Koplik, E V; Kamenov, Z A; Poletaev, A B



Delta-sleep-inducing peptide and its analogs and the serotoninergic system in the development of anticonvulsive influences  

Microsoft Academic Search

Experiments on rats were carried out to study the effects of administration of delta-sleep-inducing peptide (DSIP) and its\\u000a analogs (9–14) into the reticular part of the substantia nigra and ventral hippocampus on picrotoxin- and kainate-induced\\u000a epileptic activity. Additionally, the uptake of [3H]tryptophan by brain structures was studied. Intranigral and intrahippocampal microinjections of peptide and its analogs\\u000a were found to have

A. A. Shandra; L. S. Godlevskii; A. I. Brusentsov; V. P. Petrashevich; R. S. Vast’yanov; B. Nikel; I. I. Mikhaleva



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

Microsoft Academic Search

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

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



First and second generation H? histamine receptor antagonists produce different sleep-inducing profiles in rats.  


First generation H? histamine receptor antagonists, such as d-chlorpheniramine (d-CPA) and diphenhydramine, produce drowsiness in humans. They are currently used as over-the-counter sleep aids. However, the mechanisms underlying drowsiness induced by these H? histamine receptor antagonists remain obscure because they produce heterogeneous receptor-independent actions. Ketotifen is a second generation H? histamine receptor antagonist which is more permeable to the brain than newer H? histamine receptor antagonists. Therefore, to access sleep-inducing profiles by H? histamine receptor blocking actions, the present study compared the dose-dependent effects of diphenhydramine and ketotifen (1-40 mg/kg, intraperitoneal injection at dark onset time) on daily sleep-wake patterns in rats. Ketotifen dose-dependently decreased rapid-eye-movement (REM) sleep and increased non-REM sleep by amplifying slow-wave electroencephalogram powers. Diphenhydramine at 4 mg/kg transiently increased non-REM sleep and reduced REM sleep similar to the effects of ketotifen. The larger injections of diphenhydramine (10-40 mg/kg), however, reduced non-REM sleep, abolished slow-wave enhancements and facilitated wakefulness. The bi-directional action of diphenhydramine on sleep is similar to our former results using d-CPA. Taken together, the arousal effects caused by over-dose administrations of the first generation H? histamine receptor antagonists may be mediated by H? histamine receptor-independent actions. To further examine the tolerance of ketotifen-induced sleep, 3 mg/kg ketotifen was injected daily for 5 days 3 h before light onset time. These experiments consistently enhanced non-REM-sleep at the end of the active phase of rats, suggesting that ketotifen may function as a desirable sleep aid although the coincidental REM sleep reduction requires attention. PMID:22449385

Unno, Katsuya; Ozaki, Tomoya; Mohammad, Shahid; Tsuno, Saki; Ikeda-Sagara, Masami; Honda, Kazuki; Ikeda, Masayuki



[Shift in the content of immune cytokines in heart of mice under acoustic stress conditions and delta-sleep inducing peptide application].  


Quantitative shifts in the content of interleukine-1, -2 and -6 of the myocardium of mice under the conditions of acoustic stress and delta-sleep inducing peptide action are studied. It has been shown that injection of delta-sleep inducing peptide has no effect on the level of interleukine-1 and -2 in the myocardial tissue, whereas the quantity of interleukine-6 increased. The level of interleukine-1- and -6 in the myocardium were increased and no significant changes were observed in the level of interleukine-2 under the noise action. Interleukine-1- and -2 were not detected in the hypophysis of experimental animals of all groups (intact, under acoustic stress, under delta-sleep inducing peptide application). The level of interleukine-6 in the hypothalamus decreased under conditions of acoustic stress, whereas administration of delta-sleep inducing peptide has no effect on its level. The obtained data are considered in the context of immune modulating properties of delta-sleep inducing peptide. PMID:18560040

A?vazian, L M; Zakharian, G V; Melkonian, M M



Delta-sleep-inducing peptide and its analogs and the serotoninergic system in the development of anticonvulsive influences.  


Experiments on rats were carried out to study the effects of administration of delta-sleep-inducing peptide (DSIP) and its analogs (9-14) into the reticular part of the substantia nigra and ventral hippocampus on picrotoxin- and kainate-induced epileptic activity. Additionally, the uptake of [3H]tryptophan by brain structures was studied. Intranigral and intrahippocampal microinjections of peptide and its analogs were found to have anticonvulsant effects against both picrotoxin- and kainate-induced epileptic activity. Studies of the effects of DSIP and its structural analogs on the uptake of tryptophan by brain structures showed that peptides predominantly increased uptake of this amino acid. It is suggested that brain structures which modulate tryptophan uptake are largely responsible for the anticonvulsant actions of DSIP and its analogs. The results obtained here provide evidence that the serotoninergic system is not of key importance in mediating the anticonvulsant effects of DSIP and its analogs. PMID:9809291

Shandra, A A; Godlevskii, L S; Brusentsov, A I; Petrashevich, V P; Vast'yanov, R S; Nikel, B; Mikhaleva, I I


Restoration of emotional stress reactions in rats following disruption of the limbic structures of the brain by delta-sleep-inducing peptide  

Microsoft Academic Search

This report describes studies of delta-sleep-inducing peptide in the mechanism of compensating emotional behavior following\\u000a disruption of a number of structures of the limbic complex (the septum and amygdala). Studies were performed in male Wistar\\u000a rats. Peptide was given i.p. at a dose of 60 nmol\\/kg. The individual\\/typological characteristics of the rats' behavior and\\u000a their resistance to stress was predicted

E. V. Koplik; K. V. Sudakov



Effects of delta-sleep inducing peptide (DSIP) and some analogues on the activity of monoamine oxidase type A in rat brain under hypoxia stress  

Microsoft Academic Search

Metabolic effects of delta-sleep inducing peptide (DSIP) under hypoxia stress were investigated in rats subjected to short-term hypoxic conditions (about 0.26 Bar). It was found that DSIP partially restricted stress-induced changes in activity of mitochondrial monoamine oxidase type A (MAO-A) and serotonin level in rat brain. A number of DSIP analogues was tested and among them there were some compounds

Elena M. Khvatova; Natalia A. Rubanova; Igor A. Prudchenko; Inessa I. Mikhaleva



Lipids of human meibum: mass-spectrometric analysis and structural elucidation.  


The purpose of this study was to structurally characterize the major lipid species present in human meibomian gland secretions (MGS) of individual subjects by means of ion trap atmospheric pressure ionization mass spectrometry analysis (API MS(n)). The samples of MGS and authentic lipid standards were analyzed in direct infusion and high-pressure liquid chromatography (HPLC) experiments with API MS(n) detection of the analytes (HPLC API MS(n)). The major precursor ions were isolated and subjected to further sequential fragmentation in MS(n) experiments, and their fragmentation patterns were compared with those of authentic lipid standards. Multiple precursor ions were observed in the positive-ion mode. Among those, previously identified cholesterol (Chl; m/z 369; [M - H(2)O + H](+)) and oleic acid (OA; m/z 283; [M + H](+)) were found. The other major compounds of the general molecular formula C(n)H(2n-2)O(2) were consistent with wax esters (WEs), with OA as fatty acyl component. Accompanying them were two homologous series of compounds that fit the molecular formulas C(n)H(2n-4)O(2) and C(n)H(2n)O(2). Subset 2 was found to be a homolog series of linoleic acid-based WEs, whereas subset 3 was, apparently, a mixture of stearic acid-based WEs. HPLC API MS(n) analysis revealed the presence of large quantities of cholesteryl esters (Chl-Es) in all of the tested samples. Less than 0.1% (w/w) of oleamide was detected in human MGS. In the negative-ion mode, three major compounds with m/z values of 729, 757, and 785 that were apparently related to anionogenic lipids of the diacylglyceryl family were found in all of the samples. Common phospholipids and ceramides (Cers) were not present among the major MGS lipids. Phosphocholine-based lipids were found in MGS in quantities less than 0.01% (w/w), if at all. This ratio is two orders of magnitude lower than reported previously. These observations suggest that MGS are a major source of nonpolar lipids of the WE and Chl-E families for the tear film lipid layer, but not of its previously reported (phospho)lipid, Cer, and fatty acid amide components. PMID:17626978

Butovich, Igor A; Uchiyama, Eduardo; McCulley, James P



Evidence for a role of delta sleep-inducing peptide in slow-wave sleep and sleep-related growth hormone release in the rat.  

PubMed Central

To examine the role of delta sleep-inducing peptide (DSIP) in sleep-related growth hormone (GH) release, male rats were deprived of sleep for 4 hr by placing them on a slowly rotating wheel. Sleep deprivation by this method caused a significant increase in GH release, as indicated by the increase in plasma GH concentrations (P less than 0.01), and also in the amount of slow-wave sleep (SWS) (P less than 0.001) above initial values after removal of the animals from the rotating wheel. These increases were blocked by microinjection into the third cerebral ventricle of highly specific antiserum to DSIP. In control rats receiving an equal volume of normal rabbit serum, the significant increase in plasma GH as well as SWS remained after removal of the rats from the wheel. The increased release of endogenous DSIP in the sleep-deprived animals may have caused an increase in SWS as well as plasma GH. Since DSIP increases plasma GH after its injection into the third cerebral ventricle and since passive immunization against DSIP blocks the increase in SWS and GH release that follows the 4 hr of sleep deprivation, the results suggest that DSIP can be a physiological stimulus for sleep-related GH release as well as for the induction of SWS.

Iyer, K S; Marks, G A; Kastin, A J; McCann, S M



Lipid Nanotechnology  

PubMed Central

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

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



Lipid Storage Diseases  


NINDS Lipid Storage Diseases Information Page Condensed from Lipid Storage Diseases Fact Sheet Table of Contents (click to jump to sections) ... Organizations Additional resources from MedlinePlus What are Lipid Storage Diseases? Lipid storage diseases are a group of ...


LIPID MAPS online tools for lipid research  

Microsoft Academic Search

The LIPID MAPS consortium has developed a number of online tools for performing tasks such as drawing lipid structures and predicting possible structures from mass spectrometry (MS) data. A simple online interface has been developed to enable an end-user to rapidly generate a variety of lipid chemical structures, along with corresponding systematic names and ontological information. The structure-drawing tools are

Eoin Fahy; Manish Sud; Dawn Cotter; Shankar Subramaniam



Investigation on lipid asymmetry using lipid probes  

Microsoft Academic Search

Synthetic lipids with a nitroxide or a fluorescent probe have been extensively used during the last 30 years to determine the transmembrane diffusion of phospholipids in artificial or biological membranes. However, the relevance of data obtained with these modified lipids has sometimes been questioned. Beside possible artefacts introduced by the reporter probe, synthetic lipids used in cells often contain a

Philippe F. Devaux; Pierre Fellmann; Paulette Hervé



Lipid Storage Diseases  


... result, various lipids and particularly cholesterol accumulate inside nerve cells and cause them to malfunction. Patients with types ... storage of acidic lipid materials particularly in the nerve cells in teh central and peripheral nervous systems. GM1 ...


Lipids of Thermoplasma acidophilum  

PubMed Central

Cells of Thermoplasma acidophilum contain about 3% total lipid on a dry weight basis. Total lipid was found to contain 17.5% neutral lipid, 25.1% glycolipid, and 56.6% phospholipid by chromatography on silicic acid. The lipids contain almost no fatty acid ester groups but appear to have long-chain alkyl groups in ether linkages to glycerol. The phospholipid fraction includes a major component which represents about 80% of the lipid phosphorus and 46% of the total lipids. We believe this component to be a long-chain isopranol glycerol diether analogue of glycerolphosphoryl monoglycosyl diglyceride. The glycolipids appear to contain isopranol diether analogues. Several components of the complex, neutral lipid fraction have been identified as hydrocarbons, vitamin K2-7, and isopranol glycerol diether analogues. Sterols are present in the neutral lipids but do not appear to be synthesized by the organism. Images

Langworthy, Thomas A.; Smith, Paul F.; Mayberry, William R.



Daunorubicin Lipid Complex Injection  


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


Lipid signalling in disease  

Microsoft Academic Search

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

Roger Schneiter; Matthias P. Wymann



Autophagy regulates lipid metabolism  

Microsoft Academic Search

The intracellular storage and utilization of lipids are critical to maintain cellular energy homeostasis. During nutrient deprivation, cellular lipids stored as triglycerides in lipid droplets are hydrolysed into fatty acids for energy. A second cellular response to starvation is the induction of autophagy, which delivers intracellular proteins and organelles sequestered in double-membrane vesicles (autophagosomes) to lysosomes for degradation and use

Rajat Singh; Susmita Kaushik; Yongjun Wang; Youqing Xiang; Inna Novak; Masaaki Komatsu; Keiji Tanaka; Ana Maria Cuervo; Mark J. Czaja



Polyene-lipids: A new tool to image lipids  

Microsoft Academic Search

Microscopy of lipids in living cells is currently hampered by a lack of adequate fluorescent tags. The most frequently used tags, NBD and BODIPY, strongly influence the properties of lipids, yielding analogs with quite different characteristics. Here, we introduce polyene-lipids containing five conjugated double bonds as a new type of lipid tag. Polyene-lipids exhibit a unique structural similarity to natural

Lars Kuerschner; Christer S Ejsing; Kim Ekroos; Andrej Shevchenko; Kurt I Anderson; Christoph Thiele



Lipid Droplets And Cellular Lipid Metabolism  

PubMed Central

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

Walther, Tobias C.; Farese, Robert V.



Lipid polymorphism and protein-lipid interactions.  


Non-lamellar-forming lipids play an important role in determining the physical properties of membranes. They affect the activity of membrane proteins and peptides. In addition, peptides which lyse membranes as well as those which promote membrane fusion facilitate the formation of non-lamellar phases, either micelles, cubic or hexagonal phases. The relationship of these diverse effects on membrane curvature is discussed in relation to the function of certain peptides and proteins. Specific examples of ionophoric peptides, cytotoxic peptides and viral fusion peptides are given. In addition, we compare the modulation of the rate of photoisomerisation of an integral membrane protein, rhodopsin, by non-lamellar-forming lipids with the effects of these lipids on an amphitropic protein, protein kinase C. Among these diverse systems it is frequently observed that the modulation of biological activity can be described in terms of the effect of the peptide or protein on the relative stability of lamellar and non-lamellar structures. PMID:9804988

Epand, R M




Technology Transfer Automated Retrieval System (TEKTRAN)

The genetic basis for most of the rare lipid monogenic disorders have been elucidated, but the challenge remains in determining the combination of genes that contribute to the genetic variability in lipid levels in the general population; this has been estimated to be in the range of 40'60 per cent ...


Lipid bilayers and interfaces  

Microsoft Academic Search

In biological systems lipid bilayers are subject to many different interactions with other entities. These can range from proteins that are attached to the hydrophilic region of the bilayer or transmembrane proteins that interact with the hydrophobic region of the lipid bilayer. Interaction between two membranes is also very common. To gain more insight into the thermodynamic, structural and mechanical

R. A. Kik



Structure of lipid bilayers  

Microsoft Academic Search

The quantitative experimental uncertainty in the structure of fully hydrated, biologically relevant, fluid (LK) 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 LK phase. These

John F. Nagle; Stephanie Tristram-Nagle



Structure of lipid bilayers  

Microsoft Academic Search

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

John F. Nagle; Stephanie Tristram-Nagle



Lysosomal lipid storage diseases.  


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

Schulze, Heike; Sandhoff, Konrad



Lipids in DDGS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Distillers dried grains with soluble (DDGS) are one of the main coproducts of ethanol production from using the dry-grinding process. The lipids from corn or sorghum are not utilized in ethanol production, and are thus concentrated in DDGS. The main lipid components in corn and sorghum DDGS are tr...


Lipid oxidation in foods  

Microsoft Academic Search

This review discusses the basic chemical reactions that affect food flavor quality. Although there are many reactions that can lead to the deterioration of quality in foods, this review focuses on lipid oxidation and how it adversely affects flavor principles. It also presents technological advances for studying the basic mechanism of lipid oxidation, for measuring its intensity, and for retaining

Allen J. St. Angelo; John Vercellotti; Tom Jacks; Michael Legendre



Lipids of Archaeal Viruses  

PubMed Central

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.

Roine, Elina; Bamford, Dennis H.



Idiopathic bilateral lipid keratopathy.  

PubMed Central

A 52-year-old Mexican man presented with asymptomatic, bilaterally symmetrical lipid infiltrates of the cornea and adjacent limbus. No evidence of previous ocular disease or systemic disorder of lipid metabolism could be detected. Penetrating keratoplasty of the right eye was required. The cornea was rigid and thick, with posterior bulging into the anterior chamber. Light microscopy revealed deep corneal lipid granules, foamy histiocytes, vascularisation, and chronic non-granulomatous inflammation. Transmission electron microscopy showed extracellular lipid spaces and numerous intracytoplasmic lipid vacuoles in histiocytes, keratocytes, conjunctival epithelium, and the endothelium of blood vessels in the corneal stroma and adjacent limbal conjunctiva. Histochemical analysis revealed the presence of neutral fats, free fatty acids, cholesterol, and phospholipids. Images

Alfonso, E.; Arrellanes, L.; Boruchoff, S. A.; Ormerod, L. D.; Albert, D. M.



Lipids and lipid metabolism in eukaryotic algae  

Microsoft Academic Search

Eukaryotic algae are a very diverse group of organisms which inhabit a huge range of ecosystems from the Antarctic to deserts. They account for over half the primary productivity at the base of the food chain. In recent years studies on the lipid biochemistry of algae has shifted from experiments with a few model organisms to encompass a much larger

Irina A. Guschina; John L. Harwood



Cationic lipids for transfection.  


Among other strategies, the use of cationic lipids as autoassembling vehicles for non viral DNA transfection has received considerable attention. An exponentially growing litterature has been published on this topic (over 700 hits for the past decade, including 400 in the last two years). The present review focuses on the main present strategies aiming at improving cationic lipids induced transfection, and on some of the frequently encountered problems that should be solved to apply these non-viral vectors for human health. The review contains several sections dealing with the chemistry, physico-chemistry, cell biology, in vivo biology, and targeting of cationic-lipid DNA complexes. PMID:12678798

Nicolazzi, Céline; Garinot, Marie; Mignet, Nathalie; Scherman, Daniel; Bessodes, Michel



Sleep-Induced Changes in Associative Memory  

Microsoft Academic Search

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

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



Cytarabine Lipid Complex Injection  


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


Lipid Components of Diatoms.  

National Technical Information Service (NTIS)

The total lipids of five species of marine diatoms and one fresh-water diatom were studied chromatographically and the major components identified. All species contained glycerides, sulfoquinovosyl diglyceride, diglyceride, monogalactosyl diglyceride, pho...

M. Kates B. E. Volcani



Metabolism. Part III: Lipids.  

ERIC Educational Resources Information Center

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

Bodner, George M.



Lipid polymorphism and protein–lipid interactions  

Microsoft Academic Search

Non-lamellar-forming lipids play an important role in determining the physical properties of membranes. They affect the activity of membrane proteins and peptides. In addition, peptides which lyse membranes as well as those which promote membrane fusion facilitate the formation of non-lamellar phases, either micelles, cubic or hexagonal phases. The relationship of these diverse effects on membrane curvature is discussed in

Richard M Epand



Softening of lipid bilayers  

Microsoft Academic Search

The softening of wet lipid bilayer membranes during their gel-to-fluid first-order phase transition is studied by computer simulation of a family of two-dimensional microscopic interaction models. The models include a variable number, q, of lipid chain conformational states, where 2?q?10. Results are presented as functions of q and temperature for a number of bulk properties, such as internal energy, specific

O. G. Mouritsen; M. J. Zuckermann



Lipid partitioning after uninephrectomy  

Microsoft Academic Search

This longitudinal study addressed the sequential events and metabolic consequences of lipid partitioning following uninephrectomy.\\u000a Adult male Sprague–Dawley rats were randomized into sham operation (n = 15) or left uninephrectomy (UNX, n = 18). At 1 and 3 months post nephrectomy, three rats from each group were killed for histopathological examination of adipocyte\\u000a differentiation and lipid accumulation. Renal protein expression of the lipogenic peroxisome proliferator-activated

Hai-Lu ZhaoYi; Yi Sui; Lan He; Jing Guan; Sheng-Jun Xiao; Ding-Rong Zhong; Qing Xu; Si-En Zeng


Journal of Lipid Research  

NSDL National Science Digital Library

The Journal of Lipid Research (JLR)publishes "original articles and invited reviews on subjects involving lipids in any scientific discipline, including clinical and morphological studies." Online full-text content begins with the January 1998 issue, and will expand with each month's new issues. Online abstracts begin with the July 1965 issue. The site is produced in conjunction with Stanford University's HighWire Press.


Lipids in sea water  

Microsoft Academic Search

Acidified and filtered sea water samples which were extracted with petroleum ether and ethyl acetate have been shown to contain\\u000a a variety of lipid compounds in trace amounts. Concentrations of these solvent-soluble substances ranged from 0.5 to 6.0 mg\\/liter,\\u000a the lower concentrations being found in offshore waters. The solvent extracts of the sea water were separated into eight lipid\\u000a classes

Lela M. Jeffrey



Peroxidation of liposomal lipids  

Microsoft Academic Search

Free radicals, formed via different mechanisms, induce peroxidation of membrane lipids. This process is of great importance\\u000a because it modifies the physical properties of the membranes, including its permeability to different solutes and the packing\\u000a of lipids and proteins in the membranes, which in turn, influences the membranes’ function. Accordingly, much research effort\\u000a has been devoted to the understanding of

Ilya Pinchuk; Dov Lichtenberg



Lipids in human milk  

Microsoft Academic Search

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

Robert G. Jensen



Lipid peroxides and atherosclerosis  

Microsoft Academic Search

Plasma lipid peroxide concentrations were measured in 100 patients with occlusive arterial disease proved angiographically (50 patients with ischaemic heart disease, 50 with peripheral arterial disease) and compared with values in 75 control patients with no clinical evidence of atherosclerosis. Lipid peroxide concentrations were significantly higher in patients both with ischaemic heart disease (median 4.37 mumol\\/l (interquartile range 3.85-5.75 mumol\\/l);

M. D. Stringer; P. G. Görög; A. Freeman; V. V. Kakkar



Hepatic Lipid Metabolism  

Microsoft Academic Search

\\u000a The liver is a major regulator of lipid metabolism in the body. It plays a central role in the synthesis and degradation (oxidation)\\u000a of fatty acids. Fatty acids serve as an important source of energy as well as energy storage for many organisms and are also\\u000a pivotal for a variety of biological processes, including the synthesis of cellular membrane lipids

Jiansheng Huang; Jayme Borensztajn; Janardan K. Reddy


Lipid oxidation in food emulsions  

Microsoft Academic Search

Lipid oxidation is a major cause of quality deterioration in food emulsions. The design of foods with improved quality depends on a better understanding of the physicochemical mechanisms of lipid oxidation in these systems. The oxidation of emulsified lipids differs from that of bulk lipids, because of the presence of the droplet membrane, the interactions between the ingredients, and the

John N. Coupland; D. Julian McClements



Pharmacogenetics of lipid diseases  

PubMed Central

The genetic basis for most of the rare lipid monogenic disorders have been elucidated, but the challenge remains in determining the combination of genes that contribute to the genetic variability in lipid levels in the general population; this has been estimated to be in the range of 40-60 per cent of the total variability. Therefore, the effect of common polymorphisms on lipid phenotypes will be greatly modulated by gene-gene and gene-environment interactions. This approach can also be used to characterise the individuality of the response to lipid-lowering therapies, whether using drugs (pharmacogenetics) or dietary interventions (nutrigenetics). In this regard, multiple studies have already described significant interactions between candidate genes for lipid and drug metabolism that modulate therapeutic response--although the outcomes of these studies have been controversial and call for more rigorous experimental design and analytical approaches. Once solid evidence about the predictive value of genetic panels is obtained, risk and therapeutic algorithms can begin to be generated that should provide an accurate measure of genetic predisposition, as well as targeted behavioural modifications or drugs of choice and personalised dosages of these drugs.



Charge regulation in lipid membranes due to lipid mobility  

NASA Astrophysics Data System (ADS)

Lipid bilayer membranes are ubiquitous in biology and electrostatics play a key role in their functionality. The interfacial electrostatics of lipid bilayers involves interplay between the surface potential and charge regulation in the form of ion binding, protonation and lipid mobility. Mobile lipid charge regulation in particular is unique to lipid interfaces and is thought to be an important factor in charged macromolecule-membrane interactions. We used Atomic Force Microscopy (AFM) for the first nanometer scale experimental demonstration of mobile lipid charge regulation occurring in supported lipid bilayer membranes. By combining finite element computer simulations and experimental AFM data, we showed that mobile lipid charge regulation accounts for the short range deviations from the expected electrostatics over anionic lipids. We also accounted for van der Waal interactions and electrolyte ion binding in our calculations and found the mobility of the lipid to be the dominant factor in the short range deviations. Control experiments on silicon nitride surfaces, whose surface charges are immobile, showed that the short range deviation could be accounted for by the formation of a stem layer due to cation binding. Further evidence for tip-induced mobile lipid charge regulation was presented in the form of clear differences in the short range electrostatics of mobile fluid phase lipids when compared to immobile gel phase lipids. Furthermore, our data confirmed the theoretically predicted differences between surfaces containing mobile versus immobile charges.

Wickremasinghe, Yantrawaduge Nissanka Sirimevan


Immobilized lipid-bilayer materials  

SciTech Connect

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.

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



Immobilized lipid-bilayer materials  


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.

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



Lipid bodies and lipid body formation in an oleaginous fungus, Mortierella ramanniana var. angulispora  

Microsoft Academic Search

Mortierella ramanniana var. angulispora accumulates triacylglycerol (TG) in lipid bodies. Studies on lipid transport into lipid bodies are essential for elucidating mechanisms of lipid body formation. We used fluorescent dyes and fluorescent lipid analogs to visualize lipid body formation with a confocal laser scanning microscope. Different sizes of lipid bodies were stained by Nile red, a lipid body marker –

Yasushi Kamisaka; Naomi Noda; Tatsuya Sakai; Kazunori Kawasaki



Triclosan targets lipid synthesis  

Microsoft Academic Search

Triclosan is a broad-spectrum antibacterial and antifungal agent,, which acts by previously undetermined mechanisms, that is used in products such as antiseptic soaps, toothpastes, fabrics and plastics. Here we show that triclosan blocks lipid synthesis in Escherichia coli, and that mutations in, or overexpression of, the gene fabI (which encodes enoyl reductase, involved in fatty acid synthesis) prevents this blockage.

Laura M. McMurry; Margret Oethinger; Stuart B. Levy



Lipid multilayer gratings.  


The interaction of electromagnetic waves with matter can be controlled by structuring the matter on the scale of the wavelength of light, and various photonic components have been made by structuring materials using top-down or bottom-up approaches. Dip-pen nanolithography is a scanning-probe-based fabrication technique that can be used to deposit materials on surfaces with high resolution and, when carried out in parallel, with high throughput. Here, we show that lyotropic optical diffraction gratings--composed of biofunctional lipid multilayers with controllable heights between approximately 5 and 100 nm--can be fabricated by lipid dip-pen nanolithography. Multiple materials can be simultaneously written into arbitrary patterns on pre-structured surfaces to generate complex structures and devices, allowing nanostructures to be interfaced by combinations of top-down and bottom-up fabrication methods. We also show that fluid and biocompatible lipid multilayer gratings allow label-free and specific detection of lipid-protein interactions in solution. This biosensing capability takes advantage of the adhesion properties of the phospholipid superstructures and the changes in the size and shape of the grating elements that take place in response to analyte binding. PMID:20190751

Lenhert, Steven; Brinkmann, Falko; Laue, Thomas; Walheim, Stefan; Vannahme, Christoph; Klinkhammer, Soenke; Xu, Miao; Sekula, Sylwia; Mappes, Timo; Schimmel, Thomas; Fuchs, Harald



The Lipid World  

NASA Astrophysics Data System (ADS)

The continuity of abiotically formed bilayer membranes with similar structures in contemporary cellular life, and the requirement for microenvironments in which large and small molecules could be compartmentalized, support the idea that amphiphilic boundary structures contributed to the emergence of life. As an extension of this notion, we propose here a `Lipid World' scenario as an early evolutionary step in the emergence of cellular life on Earth. This concept combines the potential chemical activities of lipids and other amphiphiles, with their capacity to undergo spontaneous self-organization into supramolecular structures such as micelles and bilayers. In particular, the documented chemical rate enhancements within lipid assemblies suggest that energy-dependent synthetic reactions could lead to the growth and increased abundance of certain amphiphilic assemblies. We further propose that selective processes might act on such assemblies, as suggested by our computer simulations of mutual catalysis among amphiphiles. As demonstrated also by other researchers, such mutual catalysis within random molecular assemblies could have led to a primordial homeostatic system displaying rudimentary life-like properties. Taken together, these concepts provide a theoretical framework, and suggest experimental tests for a Lipid World model for the origin of life.

Segré, Daniel; Ben-Eli, Dafna; Deamer, David W.; Lancet, Doron



Optimizing Lipid Biostabilization.  

National Technical Information Service (NTIS)

Laboratory scale anaerobic digestion studies were carried out to determine the effect of high-shear mixing on the degradation of lipids. The studies showed that the intensity of mixing must be carefully tailored to the rate and type of feed if benefits ar...

W. Garner



Lipids: Absorption and transport  

Technology Transfer Automated Retrieval System (TEKTRAN)

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


Lipid nanotube or nanowire sensor  


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

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



Lipid nanotube or nanowire sensor  


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

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



Lipid profile in consecutive pregnancies  

Microsoft Academic Search

AIM: To describe the lipid profile of women prior to, during and after pregnancy and to assess the effect of consecutive pregnancies on the plasma lipid profile. METHODS: Blood lipid levels of 1752 women aged 20-45 years who delivered between 1999 and 2005 were measured. The lipid profile included total cholesterol, LDL-C (Low density lipoprotein), HDL-C (High density lipoprotein-C), VLDL-C

David Mankuta; Matan Elami-Suzin; Asher Elhayani; Shlomo Vinker



Lipid rafts and signal transduction  

Microsoft Academic Search

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-

Kai Simons; Derek Toomre



Lipids, fatty acids, and more  

Technology Transfer Automated Retrieval System (TEKTRAN)

Energy is the most expensive component in livestock diets. Lipids are concentrated energy sources and are known to affect growth, feed efficiency, feed dust, and diet palatability. A large majority of research evaluating lipids in livestock has utilized lipids of high quality, dealt mainly with anim...


Probing lipid membrane electrostatics  

NASA Astrophysics Data System (ADS)

The electrostatic properties of lipid bilayer membranes play a significant role in many biological processes. Atomic force microscopy (AFM) is highly sensitive to membrane surface potential in electrolyte solutions. With fully characterized probe tips, AFM can perform quantitative electrostatic analysis of lipid membranes. Electrostatic interactions between Silicon nitride probes and supported zwitterionic dioleoylphosphatidylcholine (DOPC) bilayer with a variable fraction of anionic dioleoylphosphatidylserine (DOPS) were measured by AFM. Classical Gouy-Chapman theory was used to model the membrane electrostatics. The nonlinear Poisson-Boltzmann equation was numerically solved with finite element method to provide the potential distribution around the AFM tips. Theoretical tip-sample electrostatic interactions were calculated with the surface integral of both Maxwell and osmotic stress tensors on tip surface. The measured forces were interpreted with theoretical forces and the resulting surface charge densities of the membrane surfaces were in quantitative agreement with the Gouy-Chapman-Stern model of membrane charge regulation. It was demonstrated that the AFM can quantitatively detect membrane surface potential at a separation of several screening lengths, and that the AFM probe only perturbs the membrane surface potential by <2%. One important application of this technique is to estimate the dipole density of lipid membrane. Electrostatic analysis of DOPC lipid bilayers with the AFM reveals a repulsive force between the negatively charged probe tips and the zwitterionic lipid bilayers. This unexpected interaction has been analyzed quantitatively to reveal that the repulsion is due to a weak external field created by the internai membrane dipole moment. The analysis yields a dipole moment of 1.5 Debye per lipid with a dipole potential of +275 mV for supported DOPC membranes. This new ability to quantitatively measure the membrane dipole density in a noninvasive manner will be useful in identifying the biological effects of the dipole potential. Finally, heterogeneous model membranes were studied with fluid electric force microscopy (FEFM). Electrostatic mapping was demonstrated with 50 nm resolution. The capabilities of quantitative electrostatic measurement and lateral charge density mapping make AFM a unique and powerful probe of membrane electrostatics.

Yang, Yi


Regulation of lipid composition in biological membranes—biophysical studies of lipids and lipid synthesizing enzymes  

Microsoft Academic Search

The study of the role played by membrane lipids, functional lipidomics, has become increasingly important in membrane biology. The physico-chemical properties of the lipids in biological membranes are subject to some fundamental requirements. In general, the acyl chains shall be in a liquid-like state to keep the membrane proteins active, and the lipids must form a bilayer structure in order

Leif Rilfors; Göran Lindblom



Lipid metabolism in Cryptococcus neoformans.  


In recent years, lipids have been shown to act as signalling molecules not only in mammalian cells but also in many other eukaryotes. Whereas in mammalian cells lipids regulate cellular functions that play crucial roles in the regulation of pathobiological processes, such as cancer, cardiovascular and neurodegenerative disorders, and inflammation, in the fungus Cryptococcus neoformans lipids play key roles in the regulation of pathogenic traits required for the development of cryptococcosis, an infectious disease particularly frequent in immunocompromised individuals. In this minireview we discuss recent advances in the understanding of lipid metabolism in this important human pathogen, highlighting the potential of fungal lipid enzymatic pathways as promising new drug targets. PMID:16696643

Shea, John M; Henry, Jennifer L; Del Poeta, Maurizio



Membrane Organization and Lipid Rafts  

PubMed Central

Cell membranes are composed of a lipid bilayer, containing proteins that span the bilayer and/or interact with the lipids on either side of the two leaflets. Although recent advances in lipid analytics show that membranes in eukaryotic cells contain hundreds of different lipid species, the function of this lipid diversity remains enigmatic. The basic structure of cell membranes is the lipid bilayer, composed of two apposing leaflets, forming a two-dimensional liquid with fascinating properties designed to perform the functions cells require. To coordinate these functions, the bilayer has evolved the propensity to segregate its constituents laterally. This capability is based on dynamic liquid–liquid immiscibility and underlies the raft concept of membrane subcompartmentalization. This principle combines the potential for sphingolipid-cholesterol self-assembly with protein specificity to focus and regulate membrane bioactivity. Here we will review the emerging principles of membrane architecture with special emphasis on lipid organization and domain formation.

Simons, Kai; Sampaio, Julio L.



Membrane organization and lipid rafts.  


Cell membranes are composed of a lipid bilayer, containing proteins that span the bilayer and/or interact with the lipids on either side of the two leaflets. Although recent advances in lipid analytics show that membranes in eukaryotic cells contain hundreds of different lipid species, the function of this lipid diversity remains enigmatic. The basic structure of cell membranes is the lipid bilayer, composed of two apposing leaflets, forming a two-dimensional liquid with fascinating properties designed to perform the functions cells require. To coordinate these functions, the bilayer has evolved the propensity to segregate its constituents laterally. This capability is based on dynamic liquid-liquid immiscibility and underlies the raft concept of membrane subcompartmentalization. This principle combines the potential for sphingolipid-cholesterol self-assembly with protein specificity to focus and regulate membrane bioactivity. Here we will review the emerging principles of membrane architecture with special emphasis on lipid organization and domain formation. PMID:21628426

Simons, Kai; Sampaio, Julio L



Seaweed lipids as nutraceuticals.  


Seaweeds are known as low-energy food. Despite low lipid content, ?-3 and ?-6 polyunsaturated fatty acids (PUFAs) introduce a significant part of seaweed lipids. PUFAs are the important components of all cell membranes and precursors of eicosanoids that are essential bioregulators of many cellular processes. PUFAs effectively reduce the risk of cardiovascular diseases, cancer, ostheoporosis, and diabetes. Because of the frequent usage of seaweeds in Asia and their increasing utilization as food also in other parts of the world, seaweeds could contribute to the improvement of a low level of ?-3 PUFAs, especially in the Western diet. The major commercial sources of ?-3 PUFAs are fish, but their wide usage as food additives is limited for the typical fishy smell, unpleasant taste, and oxidative nonstability. Nevertheless, growing requirements of healthy functional foods have led to produce PUFAs as nutraceuticals in controlled batch culture of marine microalgae, especially Thraustochytrium and Schizochytrium strains. PMID:22054960

Mišurcová, Ladislava; Ambrožová, Jarmila; Samek, Dušan



Mannosylerythritol lipids: a review  

Microsoft Academic Search

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

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



LIPID11: A Modular Framework for Lipid Simulations using Amber  

PubMed Central

Accurate simulation of complex lipid bilayers has long been a goal in condensed phase molecular dynamics (MD). Structure and function of membrane-bound proteins are highly dependent on the lipid bilayer environment and are challenging to study through experimental methods. Within Amber, there has been limited focus on lipid simulations, although some success has been seen with the use of the General Amber Force Field (GAFF). However, to date there are no dedicated Amber lipid force fields. In this paper we describe a new charge derivation strategy for lipids consistent with the Amber RESP approach, and a new atom and residue naming and type convention. In the first instance, we have combined this approach with GAFF parameters. The result is LIPID11, a flexible, modular framework for the simulation of lipids that is fully compatible with the existing Amber force fields. The charge derivation procedure, capping strategy and nomenclature for LIPID11, along with preliminary simulation results and a discussion of the planned long-term parameter development are presented here. Our findings suggest that Lipid11 is a modular framework feasible for phospholipids and a flexible starting point for the development of a comprehensive, Amber-compatible lipid force field.

Skjevik, Age A.; Madej, Benjamin D.; Walker, Ross C.; eigen, Knut T



Lipid Simulations: A Perspective on Lipids in Action  

PubMed Central

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.

Vattulainen, Ilpo; Rog, Tomasz




NASA Astrophysics Data System (ADS)

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

Sandhoff, Konrad



The life of lipid droplets  

PubMed Central

Lipid droplets are the least characterized of cellular organelles. Long considered simple lipid storage depots, these dynamic and remarkable organelles have recently been implicated in many biological processes, and we are only now beginning to gain insights into their fascinating lives in cells. Here we examine what we know of the life of lipid droplets. We review emerging data concerning their cellular biology and present our thoughts on some of the most salient questions for investigation.

Walther, Tobias C.; Farese, Robert V.



Lipids and Membrane Lateral Organization  

PubMed Central

Shortly after the elucidation of the very basic structure and properties of cellular membranes, it became evident that cellular membranes are highly organized structures with multiple and multi-dimensional levels of order. Very early observations suggested that the lipid components of biological membranes might be active players in the creation of these levels of order. In the late 1980s, several different and diverse experimental pieces of evidence coalesced together giving rise to the lipid raft hypothesis. Lipid rafts became enormously (and, in the opinion of these authors, sometimes acritically) popular, surprisingly not just within the lipidologist community (who is supposed to be naturally sensitive to the fascination of lipid rafts). Today, a PubMed search using the key word “lipid rafts” returned a list of 3767 papers, including 690 reviews (as a term of comparison, searching over the same time span for a very hot lipid-related key word, “ceramide” returned 6187 hits with 799 reviews), and a tremendous number of different cellular functions have been described as “lipid raft-dependent.” However, a clear consensus definition of lipid raft has been proposed only in recent times, and the basic properties, the ruling forces, and even the existence of lipid rafts in living cells has been recently matter of intense debate. The scenario that is gradually emerging from the controversies elicited by the lipid raft hypothesis emphasizes multiple roles for membrane lipids in determining membrane order, that encompass their tendency to phase separation but are clearly not limited to this. In this review, we would like to re-focus the attention of the readers on the importance of lipids in organizing the fine structure of cellular membranes.

Sonnino, Sandro; Prinetti, Alessandro



Lipid Advanced Glycosylation: Pathway for Lipid Oxidation in vivo  

Microsoft Academic Search

To address potential mechanisms for oxidative modification of lipids in vivo, we investigated the possibility that phospholipids react directly with glucose to form advanced glycosylation end products (AGEs) that then initiate lipid oxidation. Phospholipid-linked AGEs formed readily in vitro, mimicking the absorbance, fluorescence, and immunochemical properties of AGEs that result from advanced glycosylation of proteins. Oxidation of unsaturated fatty acid

Richard Bucala; Zenji Makita; Theodor Koschinsky; Anthony Cerami; Helen Vlassara



Food processing and lipid oxidation.  


Food lipids are principally triacylglycerides, phospholipids and sterols found naturally in most biological materials consumed as food and added as functional ingredients in many processed foods. As nutrients, lipids, especially triglycerides, are a concentrated caloric source, provide essential fatty acids and are a solvent and absorption vehicle for fat-soluble vitamins and other nutrients. The presence of fat significantly enhances the organoleptic perception of foods, which partly explains the strong preference and market advantage of fat-rich foods. As a class, lipids contribute many desirable qualities to foods, including attributes of texture, structure, mouthfeel, flavor and color. However, lipids are also one of the most chemically unstable food components and will readily undergo free-radical chain reactions that not only deteriorate the lipids but also: (a) produce oxidative fragments, some of which are volatile and are perceived as the off-flavors of rancidity, (b) degrade proteins, vitamins and pigments and (c) cross-link lipids and other macromolecules into non-nutritive polymers. Free-radical chain reactions are thermodynamically favorable, and as a result, evolutionary selection has strongly influenced the chemistry, metabolism and structure of biological cells to prevent these reactions kinetically. However, the loss of native structure and the death of cells can dramatically accelerate the deteriorative reactions of lipid oxidation. The effects of all processing steps, including raw product selection, harvesting, storage, refining, manufacturing and distribution, on the quality of lipids in the final commodity are considerable. Certain key variables now known to influence oxidative processes can be targeted to increase food lipid stability during and after processing. Retention of or addition of exogenous antioxidants is a well-known consideration, but the presence and activity of catalysts, the integrity of tissues and cells, the quantity of polyunsaturated lipids and the structural properties of the final food product, including total surface area of lipids, and the nature of surfactant materials all play important roles in final product stability. PMID:10335367

German, J B



Lipid Nanotube or Nanowire Sensor.  

National Technical Information Service (NTIS)

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

A. Noy A. B. Artyukhin M. Stadermann O. Bakajin S. Letant



Lipid content of malignant lymphomas  

Microsoft Academic Search

Lipid staining, using oil red 0 and Sudan black B stain, was carried out on frozen sections of formalin-fixed tumour tissue from 142 cases of malignant lymphoma. Most cases of Burkitt's tumour contained abundant coarse lipid droplets both within the cytoplasm of the lymphoid cells and within non-neoplastic histiocytes scattered throughout the tumour. Lymphocytic lymphomas contained little stainable fat. Histiocytic

D. H. Wright



Gene therapy for lipid disorders  

Microsoft Academic Search

Lipid disorders are associated with atherosclerotic vascular disease, and therapy is associated with a substantial reduction in cardiovascular events. Current approaches to the treatment of lipid disorders are ineffective in a substantial number of patients. New therapies for refractory hypercholesterolemia, severe hypertriglyceridemia, and low levels of high-density lipoprotein cholesterol are needed: somatic gene therapy is one viable approach. The molecular

Masa-aki Kawashiri; Daniel J Rader



Dermal extracellular lipid in birds.  


A light and electron microscopic study of the skin of domestic chickens, seagulls, and antarctic penguins revealed abundant extracellular dermal lipid and intracellular epidermal lipid. Dermal lipid appeared ultrastructurally as extracellular droplets varying from less than 1 micron to more than 25 microns in diameter. The droplets were often irregularly contoured, sometimes round, and of relatively low electron density. Processes of fibrocytes were often seen in contact with extracellular lipid droplets. Sometimes a portion of such a droplet was missing, and this missing part appeared to have been "digested away" by the cell process. In places where cells or cell processes are in contact with fact droplets, there are sometimes extracellular membranous whorls or fragments which have been associated with the presence of fatty acids. Occasionally (in the comb) free fat particles were seen in intimate contact with extravasated erythrocytes. Fat droplets were seen in the lumen of small dermal blood and lymph vessels. We suggest that the dermal extracellular lipid originates in the adipocyte layer and following hydrolysis the free fatty acids diffuse into the epidermis. Here they become the raw material for forming the abundant neutral lipid contained in many of the epidermal cells of both birds and dolphins. The heretofore unreported presence and apparently normal utilization of abundant extracellular lipid in birds, as well as the presence of relatively large droplets of neutral lipid in dermal vessels, pose questions which require a thorough reappraisal of present concepts of the ways in which fat is distributed and utilized in the body. PMID:2304082

Stromberg, M W; Hinsman, E J; Hullinger, R L



Lipids changes in liver cancer*  

PubMed Central

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

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



Modeling Lipid Membranes  

NASA Astrophysics Data System (ADS)

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.

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


Crystallizing Membrane Proteins in Lipidic Mesophases. A Host Lipid Screen  

SciTech Connect

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

Li, Dianfan; Lee, Jean; Caffrey, Martin (Trinity); (Limerick)



Crystallizing Membrane Proteins in Lipidic Mesophases. A Host Lipid Screen  

PubMed Central

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

Li, Dianfan; Lee, Jean; Caffrey, Martin



Molecular genetic approaches to defining lipid function  

PubMed Central

Lipids fulfill multiple and diverse functions in cells. Establishing the molecular basis for these functions has been challenging due to the lack of catalytic activity of lipids and the pleiotropic effects of mutations that affect lipid composition. By combining molecular genetic manipulation of membrane lipid composition with biochemical characterization of the resulting phenotypes, the molecular details of novel lipid functions have been established. This review summarizes the results of such a combined approach to defining lipid function in bacteria.

Dowhan, William



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

PubMed Central

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

Liu, Libin



Neuroimaging of lipid storage disorders.  


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 sensitive to lipid storage as the contents of the central nervous system must occupy uniform volume, and any increases in fluids or deposits will lead to pressure changes and interference with normal neurological function. In addition to primary lipid storage diseases, lysosomal storage diseases include the mucolipidoses (in which excessive amounts of lipids and carbohydrates are stored in the cells and tissues) and the mucopolysaccharidoses (in which abnormal glycosylated proteins cannot be broken down because of enzyme deficiency). Neurological dysfunction can be a manifestation of these conditions due to substrate deposition as well. This review will explore the modalities of neuroimaging that may have particular relevance to the study of the lipid storage disorder and their impact on elucidating aspects of brain function. First, the techniques will be reviewed. Next, the neuropathology of a few selected lipid storage disorders will be reviewed and the use of neuroimaging to define disease characteristics discussed in further detail. Examples of studies using these techniques will be discussed in the text. PMID:23798015

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



Renal lipid metabolism and lipotoxicity  

PubMed Central

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.

Bobulescu, Ion Alexandru



The other lipids: Ectopic lipids with emphasis on skeletal muscle  

Microsoft Academic Search

The obesity pandemic has intensified research into the multifaceted functions of adipose tissues. Recent studies are revealing\\u000a an intricate intercellular and intracellular system of lipid signaling between adipose tissue and other major peripheral organs\\u000a to control energy flux. If not controlled, minor disturbances can lead to deleterious ectopic lipids deposition with unwanted\\u000a health consequences. The pathophysiology of obesity is associated

Lan Chi T. Luu; Eric Ravussin



Iron and hydroxyl radicals in lipid oxidation: Fenton reactions in lipid and nucleic acids co-oxidized with lipid  

Microsoft Academic Search

Hydroxyl radicals can initiate lipid peroxidation in liquids, but their high reactivity affords reaction paths so short that they are unlikely to reach lipids in membrane bilayers when formed exteriorly. EPR studies of Fenton-like reactions inducing oxidation in bulk lipids indicate that iron-dependent initiation of lipid oxidation in organelles and vesicles may result from hydroxyl radicals formed within the hydrophobic

D. C. Borg; K. M. Schaich



Lipid-based fat substitutes.  


Fats and oils account for 38% of the total calories in the diet of Western populations, especially in the U.S. They provide the most concentrated source of energy, 9 kcal/g of a triacylglycerol molecule compared with 4 kcal/g provided by carbohydrate and protein. In response to consumer demands for low-calorie or calorie-free fats and their reluctance to give up the taste of fat, current research efforts have been directed toward the development of lipid-like fat substitutes. These fat substitutes contain the fatty acids found in conventional fats and oils, with all the physical and organoleptic properties of fats, but provide few or no calories in the diet. Some of the fat substitutes are modified triacylglycerols (glycerol backbone) with reduced digestion and absorption; others are digestible and nondigestible carbohydrate fatty acid esters and polyesters, respectively. Sucrose polyester (Olestra), a sucrose molecule esterified with six to either fatty acids, is the most studied of the lipid-based fat substitutes containing a carbohydrate backbone. If approved by the FDA, sucrose polyester will find application in almost all fat-containing foods. Specialty fats or fat substitutes targeted to certain individuals with special needs are being developed. Among these are the medium-chain triacylglycerols and structured lipids (glycerol backbone), or ¿nutraceuticals¿ with reduced absorption and medical applications. Enzyme biotechnology is another tool available to lipid chemists to selectively modify, esterify, transform, transesterify, and interesterify fats and oils or synthesize new lipids such as structured lipids of food, nutritional, and medical importance. These designer fats may be the trend in the future to produce medical lipids that do not occur normally in nature. The different types of lipid-based fat substitutes are reviewed with respect to their synthesis, analysis, metabolism, potential applications/uses, and the future of fat substitutes. PMID:8573281

Akoh, C C



Intracellular lipid particles of eukaryotic cells  

Microsoft Academic Search

In this review article we describe characterization of intracellular lipid particles of three different eukaryotic species, namely mammalian cells, plants and yeast. Lipid particles of all types of cells share a general structure. A hydrophobic core of neutral lipids is surrounded by a membrane monolayer of phospholipids which contains a minor amount of proteins. Whereas lipid particles from mammalian cells

Dagmar Zweytick; Karin Athenstaedt; Günther Daum



Autoxidation of Unsaturated Lipids in Food Emulsion  

Microsoft Academic Search

Unsaturated lipids having various physiological roles are of significance in biochemistry, nutrition, medicine, and food. However, the susceptibility of lipids to oxidation is a major cause of quality deterioration in food emulsions. The reaction mechanism and factors that influence oxidation are appreciably different for emulsified lipids and bulk lipids. This article gives a brief overview of the current knowledge on

Yue-E Sun; Wei-Dong Wang; Hong-Wei Chen; Chao Li



Bone lipids of marine fishes.  


Assessment of candidates for investigation of bone lipid metabolism yielded the following findings. (1) A tropical marine butterflyfish, Chaetodon ornatissimus, had oil-filled bones (66-80% lipid, percent dry weight) hence may be a suitable condidate. (2) The tropical marine fishes Exallias brevis, Pomacentrus jenkensi, and Chromus agilis, and a Canadian fish Sebastes ruberrimus, had intermediate quantities of oil in their bones (12-49% lipid). (3) In all the foregoing species the major bone lipid was triglyceride, usually more abundant in skull than spine. Sterol and phospholipid were also present. (4) The major fatty acids of the triglycerides (and phospholipids) were 16:0, 18:0, 18:1, and C20, C22 acids. Those acids were dominated by 20:4, 20:5, 22:5, and 22:6. (5) There was more total unsaturation in the bone lipids of S. ruberrimus (from 10 degrees C water; 67-72% unsaturation) compared to the tropical fish (from 25 degrees C water; 32-67% unsaturation) with the exception of E. brevis. (6) One of the tropical species (Arothron meleagris) and a Canadian Chimaeran (Hydrolagus colliei) contained only 1-3% lipid in their bones. PMID:1029017

Phleger, C F; Grimes, P W



A role for lipid droplets in inter-membrane lipid traffic  

PubMed Central

All cells have the capacity to accumulate neutral lipids and package them into lipid droplets. Recent proteomic analyses indicate that lipid droplets are not simple lipid storage depots, but rather complex organelles that have multiple cellular functions. One of these proposed functions is to distribute neutral lipids as well as phospholipids to various membrane-bound organelles within the cell. Here, we summarize the lipid droplet-associated membrane-trafficking proteins and review the evidence that lipid droplets interact with endoplasmic reticulum, endosomes, peroxisomes, and mitochondria. Based on this evidence, we present a model for how lipid droplets can distribute lipids to specific membrane compartments.

Zehmer, John K.; Huang, Youguo; Peng, Gong; Pu, Jing; Anderson, Richard G.W.



The differential protein and lipid compositions of noncaveolar lipid microdomains and caveolae  

Microsoft Academic Search

Morphologically, caveolae and lipid rafts are two different membrane structures. They are often reported to share similar lipid and protein compositions, and are considered to be two subtypes of membrane lipid microdomains. By modifying sucrose density gradient flotation centrifugation, which is used to isolate lipid microdomains, we were able to separate caveolae and noncaveolar lipid microdomains into two distinct fractions.

Yao Yao; Shangyu Hong; Hu Zhou; Taichang Yuan; Rong Zeng; Kan Liao



Exogenous Ether Lipids Predominantly Target Mitochondria  

Microsoft Academic Search

Ether lipids are ubiquitous constituents of cellular membranes with no discrete cell biological function assigned yet. Using fluorescent polyene-ether lipids we analyzed their intracellular distribution in living cells by microscopy. Mitochondria and the endoplasmic reticulum accumulated high amounts of ether-phosphatidylcholine and ether-phosphatidylethanolamine. Both lipids were specifically labeled using the corresponding lyso-ether lipids, which we established as supreme precursors for lipid

Lars Kuerschner; Doris Richter; Hans Kristian Hannibal-Bach; Anne Gaebler; Andrej Shevchenko; Christer S. Ejsing; Christoph Thiele



Effects of Lipopolysaccharide, Lipid A, Lipid X, and Phorbol Ester on Cultured Bovine Endothelial Cells,  

National Technical Information Service (NTIS)

In pursuing the mechanism of endotoxin action, we examined the effect of lipopolysaccharide (LPS) and its chemically defined components, lipid A and lipid X on cultured bovine endothelial cells. We report that LPS and lipid A caused detachment and altered...

S. L. Gartner D. G. Sieckmann Y. H. Kang L. P. Watson L. D. Homer



Iron and hydroxyl radicals in lipid oxidation: Fenton reactions in lipid and nucleic acids co-oxidized with lipid  

SciTech Connect

Hydroxyl radicals can initiate lipid peroxidation in liquids, but their high reactivity affords reaction paths so short that they are unlikely to reach lipids in membrane bilayers when formed exteriorly. EPR studies of Fenton-like reactions inducing oxidation in bulk lipids indicate that iron-dependent initiation of lipid oxidation in organelles and vesicles may result from hydroxyl radicals formed within the hydrophobic membrane interiors, where they would be inaccessible to typical hydrophilic radical scavengers. The cytotoxic or cytogenetic results of lipid peroxidation, especially in nuclear membranes, may include radiominetic chemical damage to adjacent DNA or nucleoprotein. Preliminary product analyses of nucleic acid basis cooxidized with lipids in vitro support this view.

Borg, D.C.; Schaich, K.M.



Non-vesicular lipid transport by lipid-transfer proteins and beyond  

Microsoft Academic Search

The movement of lipids within and between intracellular membranes is mediated by different lipid transport mechanisms and is crucial for maintaining the identities of different cellular organelles. Non-vesicular lipid transport has a crucial role in intracellular lipid trafficking and distribution, but its underlying mechanisms remain unclear. Lipid-transfer proteins (LTPs), which regulate diverse lipid-mediated cellular processes and accelerate vectorial transport of

Sima Lev



Computer simulations of lipid membrane domains.  


There is great diversity in the composition and structure of biological lipid membranes. We are beginning to appreciate the crucial role of lipids in many cellular processes, and characterize some of the lateral structures within membranes that could play a role in the activity of lipids. Simulations probe molecular level interactions between single molecules, which provide complementary information to experiments. Lipid membrane simulations have reached an exciting point, where the time and length scales of our simulations are approaching experimental resolutions and can be used to interpret experiments on increasingly complex model membranes. The focus of this review is on recent molecular simulations of domain formation in lipid bilayers. We highlight a number of recent examples where simulations are used in collaboration with experiments. We review recent simulation studies on lipid-lipid interactions related to domain formation and on lipid-protein interactions relevant for lipid raft function. PMID:23500617

Bennett, W F Drew; Tieleman, D Peter



Fuel from microalgae lipid products  

SciTech Connect

The large-scale production of microalgae is a promising method of producing a renewable feedstock for a wide variety of fuel products currently refined from crude petroleum. These microalgae-derived products include lipid extraction products (triglycerides, fatty acids, and hydrocarbons) and catalytic conversion products (paraffins and olefins). Microalgal biomass productivity and lipid composition of current experimental systems are estimated at 66.0 metric tons per hectare year and 30% lipid content. Similar yields in a large-scale facility indicate that production costs are approximately six times higher than the average domestic price for crude, well-head petroleum. Based on achievable targets for productivity and production costs, the potential for microalgae as a fuel feedstock is presented in context with selected process refining routes and is compared with conventional and alternative feedstocks (e.g., oilseeds) with which microalgae must compete. 24 references, 9 figures, 4 tables.

Hill, A.M.; Feinberg, D.A.



Lipids and the ocular lens.  


The unusually high levels of saturation and thus order contribute to the uniqueness of human lens membranes. In addition, and unlike in most biomembranes, most of the lens lipids are associated with proteins, thus reducing their mobility. The major phospholipid of the human lens is dihydrosphingomyelin. Found in significant quantities only in primate lenses, particularly human ones, this lipid is so extremely stable that it was reported to be the only lipid remaining in a frozen mammoth 40,000 years after its death. Unusually high levels of cholesterol add peculiarity to the composition of lens membranes. Beyond the lateral segregation of lipids into dynamic domains known as rafts, the high abundance of cholesterol in the human lens leads to the formation of patches of pure cholesterol. Changes in human lens lipid composition with age and disease as well as differences among species are greater than those observed for any other biomembrane. The relationships among lens membrane composition, structure, and lipid conformation reviewed in this article are unique to the mammalian lens and offer exciting insights into lens membrane function. This review focuses on findings reported over the last two decades that demonstrate the uniqueness of mammalian lens membranes regarding their morphology and composition. Because the membranes of human lenses do undergo the most dramatic changes with age and cataractogenesis, the final sections of this review address our current knowledge of the unusual composition and organization of adult human lens membranes with and without opacification. Finally, the questions that still remain to be answered are presented. PMID:20407021

Borchman, Douglas; Yappert, Marta C



Curvature-Driven Lipid Sorting in Biomembranes  

PubMed Central

It has often been suggested that the high curvature of transport intermediates in cells may be a sufficient means to segregate different lipid populations based on the relative energy costs of forming bent membranes. In this review, we present in vitro experiments that highlight the essential physics of lipid sorting at thermal equilibrium: It is driven by a trade-off between bending energy, mixing entropy, and interactions between species. We collect evidence that lipid sorting depends strongly on lipid–lipid and protein–lipid interactions, and hence on the underlying composition of the membrane and on the presence of bound proteins.

Callan-Jones, Andrew; Sorre, Benoit; Bassereau, Patricia



Charge-reversal lipids, peptide-based lipids, and nucleoside-based lipids for gene delivery.  


Twenty years after gene therapy was introduced in the clinic, advances in the technique continue to garner headlines as successes pique the interest of clinicians, researchers, and the public. Gene therapy's appeal stems from its potential to revolutionize modern medical therapeutics by offering solutions to myriad diseases through treatments tailored to a specific individual's genetic code. Both viral and non-viral vectors have been used in the clinic, but the low transfection efficiencies when non-viral vectors are used have lead to an increased focus on engineering new gene delivery vectors. To address the challenges facing non-viral or synthetic vectors, specifically lipid-based carriers, we have focused on three main themes throughout our research: (1) The release of the nucleic acid from the carrier will increase gene transfection. (2) The use of biologically inspired designs, such as DNA binding proteins, to create lipids with peptide-based headgroups will improve delivery. (3) Mimicking the natural binding patterns observed within DNA, by using lipids having a nucleoside headgroup, will produce unique supramolecular assembles with high transfection efficiencies. The results presented in this Account demonstrate that engineering the chemical components of the lipid vectors to enhance nucleic acid binding and release kinetics can improve the cellular uptake and transfection efficacy of nucleic acids. Specifically, our research has shown that the incorporation of a charge-reversal moiety to initiate a shift of the lipid from positive to negative net charge improves transfection. In addition, by varying the composition of the spacer (rigid, flexible, short, long, or aromatic) between the cationic headgroup and the hydrophobic chains, we can tailor lipids to interact with different nucleic acids (DNA, RNA, siRNA) and accordingly affect delivery, uptake outcomes, and transfection efficiency. The introduction of a peptide headgroup into the lipid provides a mechanism to affect the binding of the lipid to the nucleic acid, to influence the supramolecular lipoplex structure, and to enhance gene transfection activity. Lastly, we discuss the in vitro successes that we have had when using lipids possessing a nucleoside headgroup to create unique self-assembled structures and to deliver DNA to cells. In this Account, we state our hypotheses and design elements as well as describe the techniques that we have used in our research to provide readers with the tools to characterize and engineer new vectors. PMID:22439686

LaManna, Caroline M; Lusic, Hrvoje; Camplo, Michel; McIntosh, Thomas J; Barthélémy, Philippe; Grinstaff, Mark W



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

NASA Astrophysics Data System (ADS)

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.

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



Genetic engineering of plant lipids.  


Vegetable oils are a major component of human diets, comprising as much as 25% of average caloric intake. Until recently, it was not possible to exert significant control over the chemical composition of vegetable oils derived from different plants. However, the advent of genetic engineering has provided novel opportunities to tailor the composition of plant-derived lipids so that they are optimized with respect to food functionality and human dietary needs. In order to exploit this new capability, it is essential for food scientists and nutritionists to define the lipid compositions that would be most desirable for various purposes. PMID:10448522

Broun, P; Gettner, S; Somerville, C



Lipid Peroxide–DNA Adducts  

Microsoft Academic Search

\\u000a Increased production of reactive oxygen species during oxidative stress can initiate the formation of lipid hydroperoxides,\\u000a which undergo homolytic decomposition to the ?, ?-unsaturated aldehydic bifunctional electrophiles, 4-oxo-2(E)-nonenal (ONE), 4-hydroxy-2(E)-nonenal (HNE), 4-hydroperoxy-2(E)-nonenal (HPNE), and malondialdehyde (MDA). Excessive lipid hydroperoxides can also be derived from the up-regulation of\\u000a lipoxygenases (LOXs) and cyclooxygenases (COXs). Intracellular generation of the bifunctional electrophiles can then

Seon Hwa Lee; Ian A. Blair


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

NSDL National Science Digital Library

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

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



Iron and Hydroxyl Radicals in Lipid Oxidation: Fenton Reactions in Lipid and Nucleic Acids CO-Oxidized with Lipid.  

National Technical Information Service (NTIS)

Hydroxyl radicals can initiate lipid peroxidation in liquids, but their high reactivity affords reaction paths so short that they are unlikely to reach lipids in membrane bilayers when formed exteriorly. EPR studies of Fenton-like reactions inducing oxida...

D. C. Borg K. M. Schaich



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

Microsoft Academic Search

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

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



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

ERIC Educational Resources Information Center

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

Eyster, Kathleen M.



Substrate-supported lipid nanotube arrays.  

SciTech Connect

This Communication describes the self-assembly of phospholipids into lipid nanotubes inside nanoporous anodic aluminum oxide substrate. Orientations of the lipid molecules in such lipid nanoscale structures were verified by high-resolution spin labeling EPR at 95 GHz. The static order parameter of lipids in such nanotube arrays was determined from low-temperature EPR spectra and was found to be exceptionally high, S{sub static} {approx} 0.9. We propose that substrate-supported lipid nanotube arrays have potential for building robust biochips and biosensors in which rigid nanoporous substrates protect the bilayer surface from contamination. The total bilayer surface in the lipid nanotube arrays is much greater than that in the planar substrate-supported membranes. The lipid nanotube arrays seem to be suitable for developing patterned lipid deposition and could be potentially used for patterning of membrane-associated molecules.

Smirnov, A. I.; Poluektov, O. G.; Chemistry; North Carolina State



Stabilization of Lipid Membranes With Dendritic Polymers.  

National Technical Information Service (NTIS)

Ion channels incorporated into lipid bilayers can be used as chemical sensors; however, the lack of stability of these bilayers prevents their use in practical sensor devices. In this study, dendrimers were used to stabilize lipid membranes by making use ...

J. J. LaScala P. Pokhrel L. T. Piehler G. Mallick S. Karna



Lipids from the Microalga, 'Botryococcus braunii'.  

National Technical Information Service (NTIS)

A high lipid, high hydrocarbon green algae was grown in various chemical and physical environments to optimize the production of biomass and of lipids. Among the variables were temperature, light intensity, light cycling, buffering, and major and minor nu...

S. Aaronson



Reactivity of Lipids during Cereal Processing.  

National Technical Information Service (NTIS)

The study elucidates factors affecting the reactivity of lipids in multiphase food systems, such as processed cereal food products. By using oat and oat products as model materials, both enzymatic and non-enzymatic lipid reactions were studied in aqueous ...

P. Lehtinen



Resveratrol in Solid Lipid Nanoparticles  

Microsoft Academic Search

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

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



[Lipid rafts in Alzheimer's disease].  


Forty years after Singer and Nicolson (1972) announced the fluid mosaic membrane model a number of new facts caused updating of their historic view. Plasma membrane is not uniform in state of matter, i.e. fluid portion is represented by glycerophospholipids spontaneously mounted into lipid bilayer in disordered manner (Ld - liquid disordered). In such membrane numerous nanodomains (millions in single cell) known as lipid rafts (TL) and caveolae contain sphingolipids and cholesterol as well as lipid modified integral membrane proteins. Nanodomains are more rigid, denser portion of plasma membrane (Lo - liquid ordered). Nanodomains are buoyant in fluid portion of membrane and have tendency to coalesce into larger platforms to form signalosomes essential for signal transduction. TL constitutively express certain proteins (alpha subunits of heterotrimeric G proteins, secretases, caveolins, flotillin). There are other proteins found in TL after additional lipid modifications (palmitoylation, myristoylation). With regard to dementia, retrospective studies carried out in human beings point to cholesterol and TL as crucial factors in etiopathogenesis of Alzheimer's disease (AD). Chronic administration of statins to patients significantly reduced the incidence of AD. This article is intended to make closer view into the molecular basis of AD and sheds more light on possible causal links between TL and AD. PMID:23214145

Kania, Elzbieta; Pajak, Beata; Gajkowska, Barbara; Orzechowski, Arkadiusz



Electrochemistry of Bilayer Lipid Membranes.  

National Technical Information Service (NTIS)

The main objective will be to understand the mechanism of charge generation, separation and transport in electron-conducting bilayer lipid membranes in which one side of the membrane is a cathode and the other is an anode. Our approach may be thought of a...

H. T. Tien



Lipid membranes on nanostructured silicon.  

SciTech Connect

A unique composite nanoscale architecture that combines the self-organization and molecular dynamics of lipid membranes with a corrugated nanotextured silicon wafer was prepared and characterized with fluorescence microscopy and scanning probe microscopy. The goal of this project was to understand how such structures can be assembled for supported membrane research and how the interfacial interactions between the solid substrate and the soft, self-assembled material create unique physical and mechanical behavior through the confinement of phases in the membrane. The nanometer scale structure of the silicon wafer was produced through interference lithography followed by anisotropic wet etching. For the present study, a line pattern with 100 nm line widths, 200 nm depth and a pitch of 360 nm pitch was fabricated. Lipid membranes were successfully adsorbed on the structured silicon surface via membrane fusion techniques. The surface topology of the bilayer-Si structure was imaged using in situ tapping mode atomic force microscopy (AFM). The membrane was observed to drape over the silicon structure producing an undulated topology with amplitude of 40 nm that matched the 360 nm pitch of the silicon structure. Fluorescence recovery after photobleaching (FRAP) experiments found that on the microscale those same structures exhibit anisotropic lipid mobility that was coincident with the silicon substructure. The results showed that while the lipid membrane maintains much of its self-assembled structure in the composite architecture, the silicon substructure indeed influences the dynamics of the molecular motion within the membrane.

Slade, Andrea Lynn; Lopez, Gabriel P. (University of New Mexico, Albuquerque, NM); Ista, Linnea K. (University of New Mexico, Albuquerque, NM); O'Brien, Michael J. (University of New Mexico, Albuquerque, NM); Sasaki, Darryl Yoshio; Bisong, Paul (University of New Mexico, Albuquerque, NM); Zeineldin, Reema R. (University of New Mexico, Albuquerque, NM); Last, Julie A.; Brueck, Stephen R. J. (University of New Mexico, Albuquerque, NM)



You Sank My Lipid Rafts!  

ERIC Educational Resources Information Center

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

Campbell, Tessa N.



Lipid Trafficking in Plant Photosynthetic Cells  

Microsoft Academic Search

\\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

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


Lipid oxidation in muscle foods: A review  

Microsoft Academic Search

Lipid oxidation is a major cause of deterioration of the quality of stored meat arrd meat products. This review deals with the mechanism and the methods used to follow lipid oxidation, as well as the interaction of lipids\\/lipid oy~idation products with food components and their possible biological effects. Emphasis is given to the presentation of the anti- and pro-oxidant properties

D. Ladikos; V. Lougovois



Proteins mediating intra- and intercellular transport of lipids and lipid-modified proteins  

Microsoft Academic Search

Proteins mediating intra- and intercellular transport of lipids and lipid-modified proteins In this thesis, I studied the intra- and intercellular transport of lipidic molecules, in particular glycosphingolipids and lipid-modified proteins. The first part focuses on the intracellular transport of glycosphingolipids. They are thought to fulfill a multitude of biological functions, because they display a high diversity in their head group,

S. Neumann



Lipid-rich cell thyroid adenoma: histopathology with comparative lipid analysis  

Microsoft Academic Search

Summary A second case of the unique lipid-rich cell thyroid adenoma is described complemented by detailed lipid analysis. New observations were made. The cytoplasm of the tumour cells contained scattered, aggregated sudanophil crystals; under polarized light the frozen, unstained sections exhibited numerous birefringent lipid crystals; electron microscopy provided further evidence that the clear cell appearance was due to intracellular lipid

K. Tóth; I. Péter; T. Kremmer; J. Sugár



General strategies in chromatographic analysis of lipids  

Microsoft Academic Search

Lipid extracts of natural sources contain a large number of lipid classes and molecular species. Completely reproducible samples are obtained only with great care and skill. Analytical methods other than chromotography and\\/or mass spectrometry are of little use for resolution and identification of lipid molecules even in simple mixtures. The analytical information desired governs the selection of the chromatographic and

J. J. Myher; A. Kuksis



Physiological aspects of human milk lipids  

Microsoft Academic Search

Human milk from healthy and well-nourished mothers is the preferred form of feeding for all healthy newborn infants. The nutrient supply with human milk supports normal growth and development of the infant. Here the general characteristics of human milk lipids and recent knowledge on lactational physiology, composition and functional aspects of human milk lipids are discussed. Lipids in human milk

Berthold Koletzko; Maria Rodriguez-Palmero; Hans Demmelmair; Nataša Fidler; Robert Jensen; Thorsten Sauerwald



How lipid flippases can modulate membrane structure  

Microsoft Academic Search

Phospholipid flippases, are proteins able to translocate phospholipids from one side of a membrane to the other even against a gradient of concentration and thereby able to establish, or annihilate, a transmembrane asymmetrical lipid distribution. This lipid shuttling forms new membrane structures, in particular vesicles, which are associated with diverse physiological functions in eukaryotic cells such as lipid and protein

Philippe F. Devaux; Andreas Herrmann; Nina Ohlwein; Michael M. Kozlov



Lipid Bilayers on Nano-Templates.  

National Technical Information Service (NTIS)

A lipid bilayer on a nano-template comprising a nanotube or nanowire and a lipid bilayer around the nanotube or nanowire. One embodiment provides a method of fabricating a lipid bilayer on a nano-template comprising the steps of providing a nanotube or na...

A. Noy A. B. Artyukhin O. Bakajin P. Stroeve



Therapeutic applications of lipid-coated microbubbles  

Microsoft Academic Search

Lipid-coated microbubbles represent a new class of agents with both diagnostic and therapeutic applications. Microbubbles have low density. Stabilization of microbubbles by lipid coatings creates low-density particles with unusual properties for diagnostic imaging and drug delivery. Perfluorocarbon (PFC) gases entrapped within lipid coatings make microbubbles that are sufficiently stable for circulation in the vasculature as blood pool agents. Microbubbles can

Evan C. Unger; Thomas Porter; William Culp; Rachel Labell; Terry Matsunaga; Reena Zutshi



Lipid stability in meat and meat products  

Microsoft Academic Search

Lipid oxidation is one of the main factors limiting the quality and acceptability of meats and meat products. Oxidative damage to lipids occurs in the living animal because of an imbalance between the production of reactive oxygen species and the animal's defence mechanisms. This may be brought about by a high intake of oxidized lipids or poly-unsaturated fatty acids, or

P. A. Morrissey; P. J. A. Sheehy; K. Galvin; J. P. Kerry; D. J. Buckley



Dibiphytanyl Ether Lipids in Nonthermophilic Crenarchaeotes  

PubMed Central

The kingdom Crenarchaeota is now known to include archaea which inhabit a wide variety of low-temperature environments. We report here lipid analyses of nonthermophilic crenarchaeotes, which revealed the presence of cyclic and acyclic dibiphytanylglycerol tetraether lipids. Nonthermophilic crenarchaeotes appear to be a major biological source of tetraether lipids in marine planktonic environments.

DeLong, Edward F.; King, Linda L.; Massana, Ramon; Cittone, Henry; Murray, Alison; Schleper, Christa; Wakeham, Stuart G.



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

NASA Astrophysics Data System (ADS)

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.

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



Polymer lipids stabilize the ripple phase in lipid bilayers  

NASA Astrophysics Data System (ADS)

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.

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



Effect of the tranquilizer mebicar on lipid metabolism and lipid peroxidation on the model of hypokinesia in rats  

Microsoft Academic Search

Daily 18-hour hypokinesia induces atherogenic shifts in the blood lipid spectrum and activates lipid peroxidation in rats.\\u000a Mebicar is shown to have a correcting effect on lipid metabolism and on the intensity of lipid peroxidation.

I. E. Zimakova; R. R. Salikhova; T. S. Tagirova; R. S. Garaev; R. A. Kamburg; O. B. Ibragimov; M. B. Kondrat'eva



Lipid Analysis Reveals Quiescent and Regenerating Liver-Specific Populations of Lipid Droplets  

Microsoft Academic Search

The mammalian liver, a key organ in lipid homeostasis, can accumulate increased amounts of lipids in certain physiological\\u000a conditions including liver regeneration. Lipid droplets (LD), the lipid storage organelles in the cytoplasm, are composed\\u000a of a core of neutral lipids (mainly triacylglycerols and cholesteryl esters) surrounded by a monolayer of phospholipids and\\u000a cholesterol with associated proteins. It is recognized that

Itsaso García-Arcos; Paola González-Kother; Patricia Aspichueta; Yuri Rueda; Begoña Ochoa; Olatz Fresnedo



Fluorescent lipid probes: some properties and applications (a review)  

Microsoft Academic Search

Odd as it may seem, experimental challenges in lipid research are often hampered by the simplicity of the lipid structure. Since, as in protein research, mutants or overexpression of lipids are not realistic, a considerable amount of lipid research relies on the use of tagged lipid analogues. However, given the size of an average lipid molecule, special care is needed

Olaf Maier; Volker Oberle; Dick Hoekstra



Lipid sorting and multivesicular endosome biogenesis.  


Intracellular organelles, including endosomes, show differences not only in protein but also in lipid composition. It is becoming clear from the work of many laboratories that the mechanisms necessary to achieve such lipid segregation can operate at very different levels, including the membrane biophysical properties, the interactions with other lipids and proteins, and the turnover rates or distribution of metabolic enzymes. In turn, lipids can directly influence the organelle membrane properties by changing biophysical parameters and by recruiting partner effector proteins involved in protein sorting and membrane dynamics. In this review, we will discuss how lipids are sorted in endosomal membranes and how they impact on endosome functions. PMID:24086044

Bissig, Christin; Gruenberg, Jean



Emerging targets in lipid-based therapy.  


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

Tucker, Stephanie C; Honn, Kenneth V



Membrane fusion in vesicles of oligomerizable lipids.  

PubMed Central

Membrane fusion has been examined in a model system of small unilamellar vesicles of synthetic lipids that can be oligomerized through the lipid headgroups. The oligomerization can be induced either in both bilayer leaflets or in the inner leaflet exclusively. Oligomerization leads to denser lipid headgroup packing, with concomitant reduction of lipid lateral diffusion and membrane permeability. As evidenced by lipid mixing assays, electron microscopy, and light scattering, calcium-induced fusion of the bilayer vesicles is strongly retarded and inhibited by oligomerization. Remarkably, oligomerization of only the inner leaflet of the bilayer is already sufficient to affect fusion. The efficiency of inhibition and retardation of fusion critically depend on the relative amount of oligomeric lipid present, on the concentration of calcium ions, and on temperature. Implications for the mechanism of bilayer membrane fusion are discussed in terms of lipid lateral diffusion and membrane curvature effects.

Ravoo, B J; Weringa, W D; Engberts, J B



Targeting Protein Lipidation in Disease  

PubMed Central

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.

Resh, Marilyn D.



Phase Separation in Lipid Membranes  

PubMed Central

Cell membranes show complex behavior, in part because of the large number of different components that interact with each other in different ways. One aspect of this complex behavior is lateral organization of components on a range of spatial scales. We found that lipid-only mixtures can model the range of size scales, from approximately 2 nm up to microns. Furthermore, the size of compositional heterogeneities can be controlled entirely by lipid composition for mixtures such as 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)/1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/cholesterol or sphingomyelin (SM)/DOPC/POPC/cholesterol. In one region of special interest, because of its connection to cell membrane rafts, nanometer-scale domains of liquid-disordered phase and liquid-ordered phase coexist over a wide range of compositions.

Heberle, Frederick A.; Feigenson, Gerald W.



Lipid signalling in pathogenic fungi.  


In recent years, the study of lipid signalling networks has significantly increased. Although best studied in mammalian cells, lipid signalling is now appreciated also in microbial cells, particularly in yeasts and moulds. For instance, microbial sphingolipids and their metabolizing enzymes play a key role in the regulation of fungal pathogenicity, especially in Cryptococcus neoformans, through the modulation of different microbial pathways and virulence factors. Another example is the quorum sensing molecule (QSM) farnesol. In fact, this QSM is involved not only in mycelial growth and biofilm formation of Candida albicans, but also in many stress related responses. In moulds, such as Aspergillus fumigatus, QSM and sphingolipids are important for maintaining cell wall integrity and virulence. Finally, fungal cells make oxylipins to increase their virulence attributes and to counteract the host immune defences. In this review, we discuss these aspects in details. PMID:21091925

Singh, Arpita; Del Poeta, Maurizio



Lipid Chaperones and Metabolic Inflammation  

PubMed Central

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.

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



Antithrombotic lipids from Semen Persicae  

Microsoft Academic Search

Chemical investigation of Semen Persicae has led to the isolation of decane (1), triolein (2), nonacosanoic acid (3), oleic acid ethyl ester (4), palmitic acid (5), oleic acid (6) and 15,16-dihydroxy-9Z,12Z-octadecadienoic acid 2,3-dihydroxypropyl ester (7). Amongst these, compound 7 is a new lipid. Their structures were elucidated by chemical and extensive spectral analysis. Their anticoagulative activities were also evaluated in vitro,

Nian-Yun Yang; Li Liu; Wei-Wei Tao; Jin-Ao Duan; Xun-Hong Liu; Su-Ping Huang



Antimicrobic features of phenolic lipids  

Microsoft Academic Search

The connection between the efficiency of phenolic lipids and their hydrophobic property (solubility) and hydrophobic property\\u000a of microorganisms’ cell structure is shown. The mixture of amphiphilic di(oxiphenil)-phenil-methanes, which act bacteriostatically\\u000a under 15 mg\\/l, possesses maximal efficiency against Staphylococcus aureus. Against Mycobacterium smegmatis with hydrophobic cell wall, hydrophobic 2,4-dialkylocibenzol 70 mg\\/l was the most effective. Hexylresorcin (HR) stops the\\u000a development of

Yu. A. Nikolaev; I. A. Borzenkov; M. V. Kalinin; N. G. Loiko; A. L. Tarasov; V. K. Plakunov; S. S. Belyaev; N. V. Voronina; V. F. Gal’chenko; G. I. El’-Registan



Dynamics of multicomponent lipid membranes  

NASA Astrophysics Data System (ADS)

We present theoretical and computational descriptions of the dynamics of multicomponent lipid bilayer membranes. These systems are both model systems for "lipid rafts" in cell membranes and interesting physical examples of quasi-two-dimensional fluids. Our chief tool is a continuum simulation that uses a phase field to track the composition of the membrane, and solves the hydrodynamic equations exactly using the appropriate Green's function (Oseen tensor) for the membrane. We apply this simulation to describe the diffusion of domains in phase-separated membranes, the dynamics of domain flickering, and the process of phase separation in lipid membranes. We then derive an analytical theory to describe domain flickering that is consistent with our simulation results, and use this to analyze experimental measurements of membrane domains. Through this method, we measure the membrane viscosity solely from fluorescence microscopy measurements. We study phase separation in quasi-two-dimensional membranes in depth with both simulations and scaling theory, and classify the different scaling regimes and morphologies, which differ from pure two-dimensional fluids. Our results may explain previous inconsistent measurements of the dynamical scaling exponent for phase separation in membranes. We also extend our theory beyond the simplest model, including the possibility that the membrane will be viscoelastic, as well as considering the inertia of the membrane and the fluid surrounding the membrane.

Camley, Brian Andrew


Lipid transfer between cationic vesicles and lipid-DNA lipoplexes: effect of serum.  


Differential scanning calorimetry was used to examine the lipid exchange between model lipid systems, including vesicles of the cationic lipoids ethyldimyristoylphosphatidylcholine (EDMPC), ethyldipalmitoylphosphatidylcholine (EDPPC) or their complexes with DNA (lipoplexes), and the zwitterionic lipids (DMPC, DPPC). The changes of the lipid phase transition parameters (temperature, enthalpy, and cooperativity) upon consecutive temperature scans was used as an indication of lipid mixing between aggregates. A selective lipid transfer of the shorter-chain cationic lipoid EDMPC into the longer-chain aggregates was inferred. In contrast, transfer was hindered when EDMPC (but not EDPPC) was bound to DNA in the lipoplexes. These data support a simple molecular lipid exchange mechanism, but not lipid bilayer fusion. Exchange via lipid monomers is considerably more facile for the cationic ethylphosphatidylcholines than for zwitterionic phosphatidylcholines, presumably due to the higher monomer solubility of the charged lipids. With the cationic liposomes, lipid transfer was strongly promoted by the presence of serum in the dispersing medium. Serum proteins are presumed to be responsible for the accelerated transfer, since the effect was strongly reduced upon heating the serum to 80 degrees C. The effect of serum indicates that even though much lipoplex lipid is inaccessible due to the multilayered structure, the barrier due to buried lipid can be easily overcome. Serum did not noticeably promote the lipid exchange of zwitterionic liposomes. The phenomenon is of potential importance for the application of cationic liposomes to nonviral gene delivery, which often involves the presence of serum in vitro, and necessarily involves serum contact in vivo. PMID:16004959

Koynova, Rumiana; MacDonald, Robert C



Interactions between Campylobacter jejuni and lipids.  

PubMed Central

We previously showed that motility plays several key roles in Campylobacter jejuni pathogenesis, including increasing the efficiency of C. jejuni attachment to host epithelial cells. To further characterize C. jejuni attachment, we first examined the role of carbohydrates. Experiments with Chinese hamster ovary (CHO) cell mutants with defined defects in complex carbohydrate biosynthesis revealed that oligosaccharide sequences probably play a subordinate role in C. jejuni attachment to eukaryotic cells. Simple sugars such as mannose, fucose, glucose, N-acetylglucosamine, maltose, and galactose also did not significantly alter the binding of C. jejuni to CHO cells. Thin-layer chromatography overlay analysis with lipids extracted from CHO cells suggested that C. jejuni binds to lipids. Lipid binding was further investigated using a receptor-based enzyme-linked immunosorbent assay. Hydrophobic interactions were determined to play a minor role in binding, since tetramethylurea, a strong inhibitor of hydrophobic interactions, did not significantly decrease binding between C. jejuni and lipids. The interaction was dissected further by comparing the binding of C. jejuni to lipids and their derivatives. The results showed that binding was greatest to the entire lipid structure and decreased in affinity when portions of the lipid were removed. Thin-layer chromatography overlay analysis showed that lipids with unsaturated fatty acids were bound with the highest affinity. Our results suggest that C. jejuni may interact with lipids in host cell membranes. However, lipids only partially inhibited C. jejuni binding to CHO cells, suggesting that multiple interactions occur between the bacteria and host cells.

Szymanski, C M; Armstrong, G D



Specificity of Intramembrane Protein-Lipid Interactions  

PubMed Central

Our concept of biological membranes has markedly changed, from the fluid mosaic model to the current model that lipids and proteins have the ability to separate into microdomains, differing in their protein and lipid compositions. Since the breakthrough in crystallizing membrane proteins, the most powerful method to define lipid-binding sites on proteins has been X-ray and electron crystallography. More recently, chemical biology approaches have been developed to analyze protein–lipid interactions. Such methods have the advantage of providing highly specific cellular probes. With the advent of novel tools to study functions of individual lipid species in membranes together with structural analysis and simulations at the atomistic resolution, a growing number of specific protein–lipid complexes are defined and their functions explored. In the present article, we discuss the various modes of intramembrane protein–lipid interactions in cellular membranes, including examples for both annular and nonannular bound lipids. Furthermore, we will discuss possible functional roles of such specific protein–lipid interactions as well as roles of lipids as chaperones in protein folding and transport.

Contreras, Francesc-Xabier; Ernst, Andreas Max; Wieland, Felix; Brugger, Britta



Physicochemical Characteristics Of Mlinjo (Gnetum gnemon) Starch-Lipid  

Microsoft Academic Search

Physicochemical characteristics of Gnetum gnemon (mlinjo) starch-lipids as influence of different extract of lipids on changes in lipids composition were studied. The mlinjo samples were extracted sequentially with hexane for surface lipid (SL) and hot water saturated butanol for internal lipid (IL). The total lipid content (dwb) comprising surface and internal lipid was 1.93 and 14.37%. The phospholipid constituted the

Tri Agus Siswoyo



It's a lipid's world: Bioactive lipid metabolism and signaling in neural stem cell differentiation  

PubMed Central

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.

Bieberich, Erhard



Effect of brown seaweed lipids on fatty acid composition and lipid hydroperoxide levels of mouse liver.  


Brown seaweed lipids from Undaria pinnatifida (Wakame), Sargassum horneri (Akamoku), and Cystoseira hakodatensis (Uganomoku) contained several bioactive compounds, namely, fucoxanthin, polyphenols, and omega-3 polyunsaturated fatty acids (PUFA). Fucoxanthin and polyphenol contents of Akamoku and Uganomoku lipids were higher than those of Wakame lipids, while Wakame lipids showed higher total omega-3 PUFA content than Akamoku and Uganomoku lipids. The levels of docosahexaenoic acid (DHA) and arachidonic acid (AA) in liver lipids of KK-A(y) mouse significantly increased by Akamoku and Uganomoku lipid feeding as compared with the control, but not by Wakame lipid feeding. Fucoxanthin has been reported to accelerate the bioconversion of omega-3 PUFA and omega-6 PUFA to DHA and AA, respectively. The higher hepatic DHA and AA level of mice fed Akamoku and Uganomoku lipids would be attributed to the higher content of fucoxanthin of Akamoku and Uganomoku lipids. The lipid hydroperoxide levels of the liver of mice fed brown seaweed lipids were significantly lower than those of control mice, even though total PUFA content was higher in the liver of mice fed brown seaweed lipids. This would be, at least in part, due to the antioxidant activity of fucoxanthin metabolites in the liver. PMID:21405010

Airanthi, M K Widjaja-Adhi; Sasaki, Naoya; Iwasaki, Sayaka; Baba, Nobuko; Abe, Masayuki; Hosokawa, Masashi; Miyashita, Kazuo




Microsoft Academic Search

Diseases of the circulatory system, such as ischaemic heart disease and cerebrovascular disease, are a major cause of mortality among Indigenous males and females, accounting for more than one in four deaths identified as Indigenous. There are almost three times as many cardiovascular deaths as expected among Indigenous males and females, based on the all-Australian rates. The rates of death

Thomas E Thompson



Lipid phase control of DNA delivery  

SciTech Connect

Cationic lipids form nanoscale complexes (lipoplexes) with polyanionic DNA and can be utilized to deliver DNA to cells for transfection. Here we report the correlation between delivery efficiency of these DNA carriers and the mesomorphic phases they form when interacting with anionic membrane lipids. Specifically, formulations that are particularly effective DNA carriers form phases of highest negative interfacial curvature when mixed with anionic lipids, whereas less effective formulations form phases of lower curvature. Structural evolution of the carrier lipid/DNA complexes upon interaction with cellular lipids is hence suggested as a controlling factor in lipid-mediated DNA delivery. A strategy for optimizing lipofection is deduced. The behavior of a highly effective lipoplex formulation, DOTAP/DOPE, is found to conform to this 'efficiency formula'.

Koynova, Rumiana; Wang, Li; Tarahovsky, Yury; MacDonald, Robert C. (NWU)



Lipid Disturbances in Psoriasis: An Update  

PubMed Central

Psoriasis is a common disease with the population prevalence ranging from 2% to 3%. Its prevalence in the population is affected by genetic, environmental, viral, infectious, immunological, biochemical, endocrinological, and psychological factors, as well as alcohol and drug abuse. In the recent years, psoriasis has been recognised as a systemic disease associated with numerous multiorgan abnormalities and complications. Dyslipidemia is one of comorbidities in psoriatic patients. Lipid metabolism studies in psoriasis have been started at the beginning of the 20th century and are concentrated on skin surface lipids, stratum corneum lipids and epidermal phospholipids, serum lipids, dermal low-density lipoproteins in the psoriatic skin, lipid metabolism, oxidative stress and correlations between inflammatory parameters, lipid parameters and clinical symptoms of the disease. On the basis of the literature data, psoriasis can be described as an immunometabolic disease.

Pietrzak, Aldona; Michalak-Stoma, Anna; Chodorowska, Grazyna; Szepietowski, Jacek C.



Plasma lipid concentrations during episodic occupational stress  

Microsoft Academic Search

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,

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



Metals and lipid oxidation. Contemporary issues  

Microsoft Academic Search

Lipid oxidation is now recognized to be a critically important reaction in physiological and toxicological processes as well\\u000a as in food products. This provides compelling reasons to understand what causes lipid oxidation in order to be able to prevent\\u000a or control the reactions. Redox-active metals are major factors catalyzing lipid oxidation in biological systems. Classical\\u000a mechanisms of direct electron transfer

K. M. Schaich



Methodology for studying postprandial lipid metabolism  

Microsoft Academic Search

Background:Postprandial lipid metabolism in humans has deserved much attention during the last two decades. Although fasting lipid and lipoprotein parameters reflect body homeostasis to some extent, the transient lipid and lipoprotein accumulation that occurs in the circulation after a fat-containing meal highlights the individual capacity to handle an acute fat input. An exacerbated postprandial accumulation of triglyceride-rich lipoproteins in the

D Lairon; J Lopez-Miranda; C Williams



Dialysis for Intoxication with Lipid Soluble Drugs: Enhancement of Glutethimide Extraction with Lipid Dialysate.  

National Technical Information Service (NTIS)

These in vivo studies demonstrate that the removal of glutethimide during dialysis is significantly increased when lipid is substituted for the usual aqueous dialysis solution. The very low water solubility of many lipid soluble compounds probably limits ...

J. H. Shinaberger L. Shear L. E. Clayton K. G. Barry M. Knowlton




EPA Science Inventory

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


Supported Lipid Bilayer/Carbon Nanotube Hybrids  

NASA Astrophysics Data System (ADS)

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

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



Dictyostelium lipid droplets host novel proteins.  


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

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



Electrodiffusion of lipids on membrane surfaces.  


Lateral translocation of lipids and proteins is a universal process on membrane surfaces. Local aggregation or organization of lipids and proteins can be induced when the random lateral motion is mediated by the electrostatic interactions and membrane curvature. Although the lateral diffusion rates of lipids on membranes of various compositions are measured and the electrostatic free energies of predetermined protein-membrane-lipid systems can be computed, the process of the aggregation and the evolution to the electrostatically favorable states remain largely undetermined. Here we propose an electrodiffusion model, based on the variational principle of the free energy functional, for the self-consistent lateral drift-diffusion of multiple species of charged lipids on membrane surfaces. Finite sizes of lipids are modeled to enforce the geometrical constraint of the lipid concentration on membrane surfaces. A surface finite element method is developed to appropriate the Laplace-Beltrami operators in the partial differential equations of the model. Our model properly describes the saturation of lipids on membrane surfaces, and correctly predicts that the MARCKS peptide can consistently sequester three multivalent phosphatidylinositol 4,5-bisphosphate lipids through its basic amino acid residues, regardless of a wide range of the percentage of monovalent phosphatidylserine in the membrane. PMID:22667591

Zhou, Y C



Electrodiffusion of lipids on membrane surfaces  

NASA Astrophysics Data System (ADS)

Lateral translocation of lipids and proteins is a universal process on membrane surfaces. Local aggregation or organization of lipids and proteins can be induced when the random lateral motion is mediated by the electrostatic interactions and membrane curvature. Although the lateral diffusion rates of lipids on membranes of various compositions are measured and the electrostatic free energies of predetermined protein-membrane-lipid systems can be computed, the process of the aggregation and the evolution to the electrostatically favorable states remain largely undetermined. Here we propose an electrodiffusion model, based on the variational principle of the free energy functional, for the self-consistent lateral drift-diffusion of multiple species of charged lipids on membrane surfaces. Finite sizes of lipids are modeled to enforce the geometrical constraint of the lipid concentration on membrane surfaces. A surface finite element method is developed to appropriate the Laplace-Beltrami operators in the partial differential equations of the model. Our model properly describes the saturation of lipids on membrane surfaces, and correctly predicts that the MARCKS peptide can consistently sequester three multivalent phosphatidylinositol 4,5-bisphosphate lipids through its basic amino acid residues, regardless of a wide range of the percentage of monovalent phosphatidylserine in the membrane.

Zhou, Y. C.



Effects of Thyroid Dysfunction on Lipid Profile  

PubMed Central

Thyroid dysfunction has a great impact on lipids as well as a number of other cardiovascular risk factors. Hypothyroidism is relatively common and is associated with an unfavorable effect on lipids. Substitution therapy is beneficial for patients with overt hypothyroidism, improving lipid profile. However, whether subclinical hypothyroidism should be treated or not is a matter of debate. On the other hand, hyperthyroidism can be associated with acquired hypocholesterolemia or unexplained improvement of lipid profile. Overall, thyroid dysfunction should be taken into account when evaluating and treating dyslipidemic patients.

Rizos, C.V; Elisaf, M.S; Liberopoulos, E.N



Lipid nanotubule fabrication by microfluidic tweezing.  


There is currently great interest in the development of lipid enclosed systems with complex geometrical arrangements that mimic cellular compartments. With biochemical functionalization, these soft matter devices can be used to probe deeper into life's transport dominated biochemical operations. In this paper, we present a novel tool for machining lipid nanotubules by microfluidic tweezing. A bilayer poly(dimethylsiloxane) (PDMS) device was designed with a lipid reservoir that was loaded by capillary action for lipid film deposition. The lipid reservoir is vertically separated from an upper flow for controlled material wetting and the formation of giant tubule bodies. Three fluidic paths are interfaced for introduction of the giant tubules into the high velocity center of a parabolic flow profile for exposure to hydrodynamic shear stresses. At local velocities approximating 2 mm s (-1), a 300-500 nm diameter jet of lipid material was tweezed from the giant tubule body and elongated with the flow. The high velocity flow provides uniform drag for the rapid and continuous fabrication of lipid nanotubules with tremendous axial ratios. Below a critical velocity, a remarkable shape transformation occurred and the projected lipid tubule grew until a constant 3.6 mum diameter tubule was attained. These lipid tubules could be wired for the construction of advanced lifelike bioreactor systems. PMID:18503287

West, Jonathan; Manz, Andreas; Dittrich, Petra S



Lipid enrichment and selectivity of integral membrane proteins in two-component lipid bilayers  

Microsoft Academic Search

A model recently used to study lipid-protein interactions in one-component lipid bilayers (Sperotto and Mouritsen, 1991 a, b) has been extended in order to include two different lipid species characterized by different acyl-chain lengths. The model, which is a statistical mechanical lattice model, assumes that hydrophobic matching between lipid-bilayer hydrophobic thickness and hydrophobic length of the integral protein is an

Maria M. Sperotto; Ole G. Mouritsen



Preparation and characterization of monocaprate nanostructured lipid carriers  

Microsoft Academic Search

Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) are potential drug delivery systems based on solid lipids. Although both carrier types are based on solid lipids, SLN consist of pure solid lipids while NLC are made of a solid matrix entrapping liquid oil. In the present paper, aqueous dispersions of SLN and NLC were successfully prepared by an oil-in-water

Xiaohong Lin; Xinwei Li; LiQiang Zheng; Li Yu; Qiqing Zhang; Weichang Liu



Lipid binding capacity of spider hemocyanin.  


The spider hemocyanin capacity to bind different lipid classes was evaluated by measuring some binding kinetic parameters. A very high lipoprotein (VHDL) which contains hemocyanin, was isolated from Polybetes pythagoricus hemolymph plasma and delipidated. Hemocyanin was bound separately to labelled palmitic acid, phosphatidylcholine, cholesterol, and triolein resulting in several artificial lipoprotein structures. It was possible to corroborate in vitro the lipid-hemocyanin interactions which had been previously observed and, consequently, the apolipoprotein role played by the respiratory pigment of spiders. Lipoproteins were analysed by gel filtration chromatography, and three subfractions with different hemocyanin structures were obtained. The four lipid classes were only bound to the hexameric structure (420 Kda), possibly to low polarity sites. Upon radioactivity measurements of the protein-associated lipids, maximal binding ratios (Mr), dissociation constants (Kd), and the maximal binding effectiveness at low lipid concentrations (Eo) were calculated. Lipid/protein ratios were increased proportionally to each available lipid concentration, following a hyperbolic binding model. Values of saturation, affinity, and maximal binding efficiency to hemocyanin were found to be different for each lipid class assayed. The highest lipid/protein ratio (41.5) was obtained with the free fatty acid and the lowest (7.2) with triolein. Phosphatidylcholine and cholesterol showed the highest relative affinities for hemocyanin (Kd = 63 x 10(-5) M and 74 x 10(-5) M, respectively). Phosphatidylcholine at low concentrations, similar to the physiological ones, presented the highest Eo value. Maximal lipid/protein ratios reached in vitro, were greater than those in P. pythagoricus VHDL, pointing out that hemocyanin could play the apolipoprotein role even under physiological conditions with a very high plasma lipid concentration. J. Exp. Zool. 284:368-373, 1999. PMID:10451413

Cunningham, M; Gómez, C; Pollero, R




PubMed Central

The majority of retinoid (vitamin A and its metabolites) present in the body of a healthy vertebrate is contained within lipid droplets present in the cytoplasm of hepatic stellate cells (HSCs). Two types of lipid droplets have been identified through histological analysis of HSCs within the liver: smaller droplets bounded by a unit membrane and larger membrane-free droplets. Dietary retinoid intake but not triglyceride intake markedly influences the number and size of HSC lipid droplets. The lipids present in rat HSC lipid droplets include retinyl ester, triglyceride, cholesteryl ester, cholesterol, phospholipids and free fatty acids. Retinyl ester and triglyceride are present at similar concentrations, and together these two classes of lipid account for approximately three-quarters of the total lipid in HSC lipid droplets. Both adipocyte-differentiation related protein and TIP47 have been identified by immunohistochemical analysis to be present in HSC lipid droplets. Lecithin:retinol acyltransferase (LRAT), an enzyme responsible for all retinyl ester synthesis within the liver, is required for HSC lipid droplet formation, since Lrat-deficient mice completely lack HSC lipid droplets. When HSCs become activated in response to hepatic injury, the lipid droplets and their retinoid contents are rapidly lost. Although loss of HSC lipid droplets is a hallmark of developing liver disease, it is not known whether this contributes to disease development or occurs simply as a consequence of disease progression. Collectively, the available information suggests that HSC lipid droplets are specialized organelles for hepatic retinoid storage and that loss of HSC lipid droplets may contribute to the development of hepatic disease.

Blaner, William S.; O'Byrne, Sheila M.; Wongsiriroj, Nuttaporn; Kluwe, Johannes; D'Ambrosio, Diana; Jiang, Hongfeng; Schwabe, Robert F.; Hillman, Elizabeth M.C.; Piantedosi, Roseann; Libien, Jenny



Keratins and lipids in ethnic hair.  


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

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



Lipid microdomains in cell surface membranes  

Microsoft Academic Search

Lipid microdomains within cell membranes are detected by a variety of experimental techniques, each of which characterizes microdomains on a different time and spatial scale. The sum of the data on lipid microdomains has yet to be integrated into a single model of cell membrane structure. Indeed, one highlight of the past year is a new analysis of experimental results

Michael Edidin



GABA interaction with lipids in organic medium  

SciTech Connect

The interaction of TH-GABA and UC-glutamate with lipids in an aqueous organic partition system was studied. With this partition system TH-GABA and UC-glutamate were able to interact with sphingomyelin, sulfatide, phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine and phosphatidic acid but not with cholesterol or ceramide. In an homogeneous aqueous medium the authors could not demonstrate any interaction between TH-GABA-lipids. The apparent dissociation constants (K/sub d/) for TH-GABA-lipids or UC-glutamate-lipids interactions inorganic medium were in the millimolar range and maximal charge between 3 and 7 moles of GABA or glutamate by mole of lipid. Amino acids such as glutamic acid, US -alanine and glycine displaced TH-GABA with the same potency as GABA itself; thus these results show that the interaction lacks pharmacological specificity. To detect this interaction lipid concentrations higher than 2 M were required and in the partition system TH-GABA and lipid phosphorus were both concentrated at the interface. Therefore, lipids tested with a biphasic partition system do not fulfill the classical criteria for a neurotransmitter receptor at least not for GABA and glutamate. 15 references, 1 figure, 3 tables.

Beltramo, D.; Kivatinitz, S.; Lassaga, E.; Arce, A.



Quantitative metabolic profiling of lipid mediators.  


Lipids are heterogeneous biological molecules that possess multiple physiological roles including cell structure, homeostasis, and restoration of tissue functionality during and after inflammation. Lipid metabolism constitutes a network of pathways that are related at multiple biosynthetic hubs. Disregulation of lipid metabolism can lead to pathophysiological effects and multiple lipid mediators have been described to be involved in physiological processes, (e.g. inflammation). Accordingly, a thorough description of these pathways may shed light on putative relations in multiple complex diseases, including chronic obstructive pulmonary disease, asthma, Alzheimer's disease, multiple sclerosis, obesity, and cancer. Due to the structural complexity of lipids and the low abundance of many lipid mediators, mass spectrometry is the most commonly employed method for analysis. However, multiple challenges remain in the efforts to analyze every lipid subfamily. In this review, the biological role of sphingolipids, glycerolipids, oxylipins (e.g. eicosanoids), endocannabinoids, and N-acylethanolamines in relation to health and disease and the state-of-the-art analyses are summarized. The characterization and understanding of these pathways will increase our ability to examine for interrelations among lipid pathways and improve the knowledge of biological mechanisms in health and disease. PMID:23828856

Balgoma, David; Checa, Antonio; Sar, Daniel García; Snowden, Stuart; Wheelock, Craig E



Antibacterial Agents That Inhibit Lipid a Biosynthesis  

Microsoft Academic Search

Lipid A constitutes the outer monolayer of the outer membrane of Gram-negative bacteria and is essential for bacterial growth. Synthetic antibacterials were identified that inhibit the second enzyme (a unique deacetylase) of lipid A biosynthesis. The inhibitors are chiral hydroxamic acids bearing certain hydrophobic aromatic moieties. They may bind to a metal in the active site of the deacetylase. The

H. Russell Onishi; Barbara A. Pelak; Lynn S. Gerckens; Lynn L. Silver; Frederick M. Kahan; Meng-Hsin Chen; Arthur A. Patchett; Susan M. Galloway; Sheryl A. Hyland; Matt S. Anderson; Christian R. H. Raetz



Lipid uptake in expanded polytetrafluoroethylene vascular grafts  

Microsoft Academic Search

Purpose: The mechanisms of vascular prosthesis failure are reported to be associated, in part, with an atherosclerotic degenerative process that is related to an abnormal lipid infiltration. The lipid uptake in expanded polytetrafluoroethylene (ePTFE) vascular grafts was reproduced in vitro, and the effect of time on the permeability of these prostheses was studied. Methods: Water permeability tests were carried out

Patrick Vermette; Jules Thibault; Gaétan Laroche




Microsoft Academic Search

The effects of light on in vitro skin lipid metabolism were examined. Fresh human skin specimens were irradiated with a Xenon lamp at a level equivalent to 10 x the minimal erythema dose. After irradiation the skin specimens were incubated 6 hours in the presence of 14C-acetate. Total lipids were extracted and the levels of acetate incorporation determined. The total

Homer S. Black; Elizabeth W. Rauschkolb



Single molecule dynamics in lipid membranes  

NASA Astrophysics Data System (ADS)

Lipid membranes are self-assembled molecular materials that form the membranes of cells. Because of their biological function, lipid membranes are important from a biomedical and biotechnological standpoint. Because of their complex fluid properties, they also provide a rich testbed for studying the structure and dynamics in self-assembled materials and for developing other bio-mimetic structures. In this work, we studied the dynamics of single lipid molecules using experimental and computational techniques. Using single molecule fluorescence microscopy, we tracked the diffusive motion of lipids in phase separated lipid membranes. With the additional techniques of atomic force microscopy and Monte Carlo simulation, we were able to, for the first time experimentally, directly correlate the observed obstructed diffusion with lipid membrane organization. The single molecule tracking tracking experiments required the addition of impurity fluorescent molecules and the assumption that the impurities do not alter the dynamics of the system. To test this assumption, we performed atomistic molecular dynamics simulations of a fluorescently labeled lipid in a lipid membrane. We showed that the fluorescent impurity could have a significant impact on some membrane properties, such as phase behavior, but that relative changes in diffusive behavior are unaffected.

Skaug, Michael James


Lipoprotein lipase: genetics, lipid uptake, and regulation  

Microsoft Academic Search

Lipoprotein lipase (LPL) regulates the plasma levels of triglyceride and HDL. Three aspects are reviewed. 1 ) Clinical implications of human LPL gene variations: com- mon mutations and their effects on plasma lipids and coro- nary heart disease are discussed. 2 ) LPL actions in the ner- vous system, liver, and heart: the discussion focuses on LPL and tissue lipid

Martin Merkel; Robert H. Eckel; Ira J. Goldberg



[Low temperature phosphorescence of lipid peroxidation products].  


The phosphorescence exitation and emission spectra and the phosphorescence lifetimes of polymerized malonic aldehyde, Shiff bases, linoleic acid, phosphatidylcholine, phosphatidylethanolamine, cardiolipine, total lipid fraction from human erythrocyte membranes were measured at 77 K. The nature of chromophores of lipid peroxidation products capable of phosphorescence was discussed. PMID:9702337

Mazhul', V M; Shcherbin, D G


Neutral lipids of Citrullus vulgaris seeds  

Microsoft Academic Search

The qualitative and quantitative compositions of the neutral lipids of watermelon seeds have been studied. The fatty acid compositions of the acyl-containing lipids have been determined. In the triacylglycerols the main forms are those in which the sn-2 position is substituted by linoleic acid.

M. M. Rakhimov; T. A. Aliev; I. Tolibaev



Vesicle trafficking from a lipid perspective  

PubMed Central

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

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



Lipid conversions during enrichment of Artemia  

Microsoft Academic Search

Artemia nauplii were enriched for 24 h with radiolabelled fatty acid ethyl esters and then starved for a subsequent period of 24 h. Analyses of the distribution of radioactivity in lipids from samples taken at the end of the enrichment period and after the subsequent starvation showed that the ethyl esters were readily converted into other lipid classes, mainly triacylglycerols,

Juan C Navarro; R. James Henderson; Lesley A McEvoy; Michael V Bell; Francisco Amat



Pasting characteristics of starch-lipid composites  

Technology Transfer Automated Retrieval System (TEKTRAN)

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


Membrane lipids and cell death: an overview  

Microsoft Academic Search

In this article we overview major aspects of membrane lipids in the complex area of cell death, comprising apoptosis and various forms of programmed cell death. We have focused here on glycerophospholipids, the major components of cellular membranes. In particular, we present a detailed appraisal of mitochondrial lipids that attract increasing interest in the field of cell death, while the

Ileana M. Cristea; Mauro Degli Esposti



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

SciTech Connect

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.

Christopher Benning



21 CFR 862.1470 - Lipid (total) test system.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Lipid (total) test system. 862.1470 Section...Clinical Chemistry Test Systems § 862.1470 Lipid (total) test system. (a) Identification. A lipid (total) test system is a device...



21 CFR 862.1470 - Lipid (total) test system.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Lipid (total) test system. 862.1470 Section...Clinical Chemistry Test Systems § 862.1470 Lipid (total) test system. (a) Identification. A lipid (total) test system is a device...



Hepatitis C Virus Hijacks Host Lipid Metabolism  

PubMed Central

Hepatitis C virus (HCV) modulates cellular lipid metabolism to enhance its replication. HCV circulates in the blood in association with lipoproteins. HCV infection is associated with enhanced lipogenesis, reduced secretion and ?-oxidation of lipids. HCV-induced imbalance in lipid homeostasis leads to steatosis. Many lipids are crucial for viral life cycle, and inhibitors of cholesterol/fatty acid biosynthetic pathways inhibit viral replication, maturation and secretion. HCV negatively modulates the synthesis and secretion of very low-density lipoproteins (VLDL). The components involved in VLDL assembly are also required for HCV morphogenesis/secretion, suggesting that HCV coopts the VLDL secretory pathway for its own secretion. This review highlights HCV-altered lipid metabolic events that aid in the viral life cycle and ultimately promote liver disease pathogenesis.

Syed, Gulam H; Amako, Yutaka; Siddiqui, Aleem



Model Answers to Lipid Membrane Questions  

PubMed Central

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

Mouritsen, Ole G.



Novel insights into lipid antigen presentation.  


T cells recognizing lipid antigens are present in large numbers in circulating blood. They exert multiple functions including immunoregulation, tumour surveillance and protection during infection. Here, we review the latest information on the mechanisms of lipid antigen presentation by CD1 molecules. Recent studies have provided insight into CD1 trafficking within the cell, lipid distribution and handling, CD1 maturation, lipid antigen processing and loading. The structural resolution of all human CD1 molecules has revealed unique features that correlate with function. Molecular mechanisms regulating CD1 expression and multiple evasion mechanisms evolved by viral and bacterial pathogens have been disclosed. With rapid progression, these studies have decoded lipid-specific immunity and have revealed the important immunological role of this type of antigen recognition. PMID:22342205

De Libero, Gennaro; Mori, Lucia



Lipid metabolism in microalgae distinguishes itself.  


Microalgae are attracting renewed interest from both the scientific and public communities owing to their potential applications as sustainable feed stocks for the production of biofuels and high value compounds, and environmental remediation. Recent advances in molecular and biochemical analyses of microalgae point toward interesting differences in lipid metabolism between algal species and in comparison to plants. These differences range from distinct acyl groups present in algal lipids, to a possible more direct role of plastids in the assembly of TAGs with consequences for the overall subcellular organization of glycerolipid metabolism. Thus, studying lipid metabolism in microalgae points to new possible avenues of genetic engineering of lipid metabolism in this organism group, and may also inform studies of lipid metabolism in plants. PMID:22981869

Liu, Bensheng; Benning, Christoph



?-Synuclein senses lipid packing defects and induces lateral expansion of lipids leading to membrane remodeling.  


There is increasing evidence for the involvement of lipid membranes in both the functional and pathological properties of ?-synuclein (?-Syn). Despite many investigations to characterize the binding of ?-Syn to membranes, there is still a lack of understanding of the binding mode linking the properties of lipid membranes to ?-Syn insertion into these dynamic structures. Using a combination of an optical biosensing technique and in situ atomic force microscopy, we show that the binding strength of ?-Syn is related to the specificity of the lipid environment (the lipid chemistry and steric properties within a bilayer structure) and to the ability of the membranes to accommodate and remodel upon the interaction of ?-Syn with lipid membranes. We show that this interaction results in the insertion of ?-Syn into the region of the headgroups, inducing a lateral expansion of lipid molecules that can progress to further bilayer remodeling, such as membrane thinning and expansion of lipids out of the membrane plane. We provide new insights into the affinity of ?-Syn for lipid packing defects found in vesicles of high curvature and in planar membranes with cone-shaped lipids and suggest a comprehensive model of the interaction between ?-Syn and lipid bilayers. The ability of ?-Syn to sense lipid packing defects and to remodel membrane structure supports its proposed role in vesicle trafficking. PMID:23740253

Ouberai, Myriam M; Wang, Juan; Swann, Marcus J; Galvagnion, Celine; Guilliams, Tim; Dobson, Christopher M; Welland, Mark E



Lipins: Multifunctional Lipid Metabolism Proteins  

PubMed Central

The lipin proteins are evolutionarily conserved proteins with roles in lipid metabolism and disease. There are three lipin protein family members in mammals and one or two orthologs in plants, invertebrates, and single-celled eukaryotes. Studies in yeast and mouse led to the identification of two distinct molecular functions of lipin proteins. Lipin proteins have phosphatidate phosphatase activity and catalyze the formation of diacylglycerol in the glycerol-3-phosphate pathway, implicating them in the regulation of triglyceride and phospholipid biosynthesis. Mammalian lipin proteins also possess transcriptional coactivator activity and have been implicated in the regulation of metabolic gene expression. Here we review key findings in the field that demonstrate roles for lipin family members in metabolic homeostasis and in rare human diseases, and we examine evidence implicating genetic variations in lipin genes in common metabolic dysregulation such as obesity, hyperinsulinemia, hypertension, and type 2 diabetes.

Csaki, Lauren S.; Reue, Karen



Energy transfer in lipid bilayers.  

PubMed Central

The quenching of fluorescence due to energy transfer between a dilute, random array of donor and acceptor chromophores in lipid bilayer was measured and compared to theoretical expressions developed to predict the decrease in emission intensity under these circumstances. The observed intensity was found to be the same function of quencher concentration in both planar, multilamellar dispersions and small, spherical vesicles. The degree of quenching was accurately predicted by a simple relation derived in this paper, as well as a more complex equation previously developed by Tweet, et al. The results suggest that significant quenching may be observed even when the average donor-acceptor separation exceeds the Förster critical distance by severalfold. Application of these results to problems of current interest in membrane research are discussed.

Estep, T N; Thompson, T E



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

PubMed Central

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.

Hunter, D G; Frisken, B J



Nuclear lipid droplets: a novel nuclear domain.  


We investigated nuclear neutral-lipid (NL) composition and organization, as NL may represent an alternative source for providing fatty acids and cholesterol (C) to membranes, signaling paths, and transcription factors in the nucleus. We show here that nuclear NL were organized into nonpolar domains in the form of nuclear-lipid droplets (nLD). By fluorescent confocal microscopy, representative nLD were observed in situ within the nuclei of rat hepatocytes in vivo and HepG2 cells, maintained under standard conditions in culture, and within nuclei isolated from rat liver. nLD were resistant to Triton X-100 and became stained with Sudan Red, OsO4, and BODIPY493/503. nLD and control cytosolic-lipid droplets (cLD) were isolated from rat-liver nuclei and from homogenates, respectively, by sucrose-gradient sedimentation. Lipids were extracted, separated by thin-layer chromatography, and quantified. nLD were composed of 37% lipids and 63% proteins. The nLD lipid composition was as follows: 19% triacylglycerols (TAG), 39% cholesteryl esters, 27% C, and 15% polar lipids; whereas the cLD composition contained different proportions of these same lipid classes, in particular 91% TAG. The TAG fatty acids from both lipid droplets were enriched in oleic, linoleic, and palmitic acids. The TAG from the nLD corresponded to a small pool, whereas the TAG from the cLD constituted the main cellular pool (at about 100% yield from the total homogenate). In conclusion, nLD are a domain within the nucleus where NL are stored and organized and may be involved in nuclear lipid homeostasis. PMID:23098923

Layerenza, J P; González, P; García de Bravo, M M; Polo, M P; Sisti, M S; Ves-Losada, A



Elimination and tissue distribution of the monosaccharide lipid A precursor, lipid X, in mice and sheep.  

PubMed Central

Lipid X (2,3-diacylglucosamine 1-phosphate) is a novel monosaccharide precursor of lipid A (the active moiety of gram-negative endotoxin) and has been found to be protective against endotoxin administered to mice and sheep and against life-threatening gram-negative infections in mice. Because of the need to design optimal dosing regimens in experimental models of ovine and murine septicemia, the pharmacokinetic profile of lipid X was investigated in sheep and in two strains of mice by using 32P-labeled lipid X. In sheep, peak whole blood lipid X levels after a bolus injection of 100 micrograms of lipid X per kg were 900 ng/ml. An initial rapid distribution phase of 7.98 +/- 0.1 min was observed, followed by a prolonged elimination phase of 3.0 +/- 0.5 h; the area under the curve from time zero to infinity was 428 +/- 27 ng.h/ml. The serum half-lives of lipid X were slightly shorter than whole blood half-lives, suggesting that lipid X associates with cellular elements. Metabolites of lipid X could not be detected in serum over a 4-h period. Lipid X appears to accumulate mainly in the liver, and the tissue distribution of lipid X resembles that of lipopolysaccharide. The elimination rate of lipid X in mice was approximately four times as rapid as that seen in sheep. Lipid X pharmacokinetics in lipopolysaccharide-sensitive DBA/2J mice were virtually identical with those seen in endotoxin-resistant C3H/HeJ mice. The pharmacokinetics described here should greatly aid in the design and interpretation of animal studies investigating the therapeutic applications of lipid X in gram-negative septicemia.

Golenbock, D T; Ebert, S; Will, J A; Proctor, R A



Effect of Lipid Peroxidation on the Properties of Lipid Bilayers: A Molecular Dynamics Study  

PubMed Central

Lipid peroxidation plays an important role in cell membrane damage. We investigated the effect of lipid peroxidation on the properties of 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphatidylcholine (PLPC) lipid bilayers using molecular dynamics simulations. We focused on four main oxidation products of linoleic acid with either a hydroperoxide or an aldehyde group: 9-trans, cis-hydroperoxide linoleic acid, 13-trans, cis-hydroperoxide linoleic acid, 9-oxo-nonanoic acid, and 12-oxo-9-dodecenoic acid. These oxidized chains replaced the sn-2 linoleate chain. The properties of PLPC lipid bilayers were characterized as a function of the concentration of oxidized lipids, with concentrations from 2.8% to 50% for each oxidation product. The introduction of oxidized functional groups in the lipid tail leads to an important conformational change in the lipids: the oxidized tails bend toward the water phase and the oxygen atoms form hydrogen bonds with water and the polar lipid headgroup. This conformational change leads to an increase in the average area per lipid and, correspondingly, to a decrease of the bilayer thickness and the deuterium order parameters for the lipid tails, especially evident at high concentrations of oxidized lipid. Water defects are observed in the bilayers more frequently as the concentration of the oxidized lipids is increased. The changes in the structural properties of the bilayer and the water permeability are associated with the tendency of the oxidized lipid tails to bend toward the water interface. Our results suggest that one mechanism of cell membrane damage is the increase in membrane permeability due to the presence of oxidized lipids.

Wong-ekkabut, Jirasak; Xu, Zhitao; Triampo, Wannapong; Tang, I-Ming; Tieleman, D. Peter; Monticelli, Luca



Lipid bilayers: thermodynamics, structure, fluctuations, and interactions  

PubMed Central

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.

Tristram-Nagle, Stephanie; Nagle, John F.



Biomarkers of lipid peroxidation in clinical material.  


BACKGROUND: Free radical-mediated lipid peroxidation has been implicated in a number of human diseases. Diverse methods have been developed and applied to measure lipid peroxidation products as potential biomarkers to assess oxidative stress status in vivo, discover early indication of disease, diagnose progression of disease, and evaluate the effectiveness of drugs and antioxidants for treatment of disease and maintenance of health, respectively. However, standardized methods are not yet established. SCOPE OF REVIEW: Characteristics of various lipid peroxidation products as biomarkers are reviewed on the basis of mechanisms and dynamics of their formation and metabolism and also on the methods of measurement, with an emphasis on the advantages and limitations. MAJOR CONCLUSIONS: Lipid hydroxides such as hydroxyoctadecadienoic acids (HODE), hydroxyeicosatetraenoic acids (HETE), and hydroxycholesterols may be recommended as reliable biomarkers. Notably, the four HODEs, 9-cis,trans, 9-trans,trans, 13-cis,trans, and 13-trans,trans-HODE, can be measured separately by LC-MS/MS and the trans,trans-forms are specific marker of free radical mediated lipid peroxidation. Further, isoprostanes and neuroprostanes are useful biomarker of lipid peroxidation. It is important to examine the distribution and temporal change of these biomarkers. GENERAL SIGNIFICANCE: Despite the fact that lipid peroxidation products are non-specific biomarkers, they will enable to assess oxidative stress status, disease state, and effects of drugs and antioxidants. This article is part of a Special Issue entitled Current methods to study reactive oxygen species-Pros and cons. PMID:23541987

Niki, Etsuo



Microfluidic fabrication of asymmetric giant lipid vesicles  

PubMed Central

We have developed a microfluidic technology for the fabrication of compositionally asymmetric giant unilamellar vesicles (GUVs). The vesicles are assembled in two independent steps. In each step, a lipid monolayer is formed at a water-oil interface. The first monolayer is formed inside of a microfluidic device with a multiphase droplet flow configuration consisting of a continuous oil stream in which water droplets are formed. These droplets are dispensed into a vessel containing a layer of oil over a layer of water. The second lipid monolayer is formed by transferring the droplets through this second oil-water interface by centrifugation. By dissolving different lipid compositions in the different oil phases, the composition of each leaflet of the resulting lipid bilayer can be controlled. We have demonstrated membrane asymmetry by showing differential fluorescence quenching of labeled lipids in each leaflet and by demonstrating that asymmetric GUVs will bind an avidin-coated surface only when biotinylated lipids are targeted to the outer leaflet. In addition, we have demonstrated the successful asymmetric targeting of phosphatidylserine lipids to each leaflet, producing membranes with a biomimetic and physiologically relevant compositional asymmetry.

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



Analysis of meibum and tear lipids.  


The meibum is a lipid-rich secretion that is the primary component of the external layer of the tear film. The meibomian glands produce the meibum, and meibomian gland dysfunction can lead to degradation of the tear film. Such dysfunction can result in ocular irritation, inflammation, and clinical disease. Understanding this relationship is critical to preventing ocular disease; therefore, a search of peer-reviewed literature focusing on the collection, quantification, and analysis of normal and abnormal meibum and tear lipids was conducted. Numerous collection and quantification techniques are described, including their advantages and disadvantages. Studies indicate that the meibum and tear lipids consist of a large array of polar and nonpolar lipids; individual lipids or their classes can be correlated to pathology. Significant amounts of lipids are deposited on contact lenses, depending on the nature of their polymer chemistry. These findings taken together indicate that normal meibum and tear lipids are essential for normal ocular health. Additional studies are required to provide a better understanding of the meibum and tear film biomolecules so that more effective treatments for blepharitis, dry eye disease, and tear film-related contact lens complications can be devised. PMID:23084145

Pucker, Andrew D; Nichols, Jason J



Lipid storage and mobilization pathways in yeast.  


Biochemistry, cell biology and molecular biology of lipids can be properly studied using the yeast Saccharionyces cerevisiae as a model system. We employ this microorganism to investigate pathways of neutral lipid (triacylglycerol, steryl ester) synthesis, storage and mobilization and to identify major gene products involved in these processes. The steryl ester synthases Are1p and Are2p were shown to catalyze steryl ester formation, and Dgalp and Lro1p were identified as major enzymes of triacylglycerol synthesis. Both triacylglycerols and steryl esters are stored in lipid particles, an intracellular compartment that is structurally reminiscent of lipoproteins. Neutral lipid mobilization is initiated by the triacylglycerol lipases Tgl3p, Tgl4p and Tgl5p, and the steryl ester hydrolases Tgl1p, Yeh1p and Yeh2p. The acyltransferases Are1p, Are1p, Lro1p and Dgalp are located in the endoplasmic reticulum, but a substantial amount of Dgalp is also present in lipid particles. The three triacylglycerol lipases as well as Tgl1p and Yeh1p are components of lipid particles, whereas Yeh2p was detected in the plasma membrane. Thus, enzymatic steps of triacylglycerol and steryl ester metabolism are located in different subcellular compartments. Consequently, regulation of neutral lipid metabolism does not only occur at the enzymatic level but also at the organelle level. PMID:18269180

Daum, Günther; Wagner, Andrea; Czabany, Tibor; Grillitsch, Karlheinz; Athenstaedt, Karin



DNA release from lipoplexes by anionic lipids: correlation with lipid mesomorphism, interfacial curvature, and membrane fusion  

SciTech Connect

DNA release from lipoplexes is an essential step during lipofection and is probably a result of charge neutralization by cellular anionic lipids. As a model system to test this possibility, fluorescence resonance energy transfer between DNA and lipid covalently labeled with Cy3 and BODIPY, respectively, was used to monitor the release of DNA from lipid surfaces induced by anionic liposomes. The separation of DNA from lipid measured this way was considerably slower and less complete than that estimated with noncovalently labeled DNA, and depends on the lipid composition of both lipoplexes and anionic liposomes. This result was confirmed by centrifugal separation of released DNA and lipid. X-ray diffraction revealed a clear correlation of the DNA release capacity of the anionic lipids with the interfacial curvature of the mesomorphic structures developed when the anionic and cationic liposomes were mixed. DNA release also correlated with the rate of fusion of anionic liposomes with lipoplexes. It is concluded that the tendency to fuse and the phase preference of the mixed lipid membranes are key factors for the rate and extent of DNA release. The approach presented emphasizes the importance of the lipid composition of both lipoplexes and target membranes and suggests optimal transfection may be obtained by tailoring lipoplex composition to the lipid composition of target cells.

Tarahovsky, Yury S.; Koynova, Rumiana; MacDonald, Robert C. (Northwestern)



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

NASA Astrophysics Data System (ADS)

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.

Haugen, Andrew; May, Sylvio



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


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. PMID:9336190

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



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

PubMed Central

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

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



Lipid nanoscaffolds in carbon nanotube arrays  

NASA Astrophysics Data System (ADS)

We present the fabrication of lipid nanoscaffolds inside carbon nanotube arrays by employing the nanostructural self-assembly of lipid molecules. The nanoscaffolds are finely tunable into model biomembrane-like architectures (planar), soft nanochannels (cylindrical) or 3-dimensionally ordered continuous bilayer structures (cubic). Carbon nanotube arrays hosting the above nanoscaffolds are formed by packing of highly oriented multiwalled carbon nanotubes which facilitate the alignment of lipid nanostructures without requiring an external force. Furthermore, the lipid nanoscaffolds can be created under both dry and hydrated conditions. We show their direct application in reconstitution of egg proteins. Such nanoscaffolds find enormous potential in bio- and nano-technological fields.We present the fabrication of lipid nanoscaffolds inside carbon nanotube arrays by employing the nanostructural self-assembly of lipid molecules. The nanoscaffolds are finely tunable into model biomembrane-like architectures (planar), soft nanochannels (cylindrical) or 3-dimensionally ordered continuous bilayer structures (cubic). Carbon nanotube arrays hosting the above nanoscaffolds are formed by packing of highly oriented multiwalled carbon nanotubes which facilitate the alignment of lipid nanostructures without requiring an external force. Furthermore, the lipid nanoscaffolds can be created under both dry and hydrated conditions. We show their direct application in reconstitution of egg proteins. Such nanoscaffolds find enormous potential in bio- and nano-technological fields. Electronic supplementary information (ESI) available: Additional wide angle X-ray scattering (WAXS) data on the alignment of lipid nanostructures, control and time resolved 2-d images of egg ovalbumin encapsulation and a summary picture of the present work. See DOI: 10.1039/c3nr02068a

Paukner, Catharina; Koziol, Krzysztof K. K.; Kulkarni, Chandrashekhar V.



Hold the antioxidants and improve plasma lipids?  

PubMed Central

Intrahepatic proteolysis is a major determinant of secretion of ApoB-containing lipoproteins into plasma. Stimulation of post-ER presecretory proteolysis (PERPP) of ApoB by n-3 polyunsaturated fatty acids has been found to result in reduced secretion of VLDL particles by hepatocytes. A new study has shown that this stimulation is promoted by pro-oxidant conditions that result in increased hepatic lipid hydroperoxide content. Conversely, PERPP is suppressed by antioxidants and by saturated fatty acids, which are not susceptible to lipid peroxidation. Hence reduction of oxidative stress may have the unexpected side effect of increasing plasma lipid levels.

Krauss, Ronald M.



Lipid Metabolism and Toxicity in the Heart  

PubMed Central

The heart has both the greatest caloric needs and the most robust oxidation of fatty acids. Under pathological conditions such as obesity and type 2 diabetes, cardiac uptake and oxidation are not balanced and hearts accumulate lipid potentially leading to cardiac lipotoxicity. We will first review the pathways utilized by the heart to acquire fatty acids from the circulation and to store triglyceride intracellularly. Then we will describe mouse models in which excess lipid accumulation causes heart dysfunction and experiments performed to alleviate this toxicity. Finally, the known relationships between heart lipid metabolism and dysfunction in humans will be summarized.

Goldberg, Ira J.; Trent, Chad M.; Schulze, P. Christian



Sterol lipids in finger millet (Eleusine coracana)  

Microsoft Academic Search

Neutral lipids, glycolipids, and phospholipids (1.3%, 0.25%, and 0.10% of seed weight) were isolated from the total lipids\\u000a (chloroform-methanol) of finger millet seeds(Eleusine coracana), and four sterol-containing lipids further isolated from neutral and glycolipids by preparative column and thin layer chromatography.\\u000a On seed weight, these comprised: free sterols (S) 0.091%, sterol esters (SE) 0.013%, sterol glycosides (SG) 0.025%, acyl sterol

V. G. Mahadevappa; P. L. Raina



Effect of short- and long-term lipid enrichment on total lipids, lipid class and fatty acid composition in rotifers  

Microsoft Academic Search

Four emulsions differing in lipid class composition: triacylglycerols, ethyl esters, phospholipids and wax esters were used to enrich rotifers either through short-term (ST) enrichment (24 h) or through long-term (LT) enrichment (10 days). Higher lipid levels were obtained by using the ST enrichment method. This was particularly marked in the high triacylglycerol accumulation in rotifers enriched on the phospholipid-based emulsion.

Jose R. Rainuzzo; Kjell I. Reitan; Yngvar Olsen



Update of the LIPID MAPS comprehensive classification system for lipids1  

PubMed Central

In 2005, the International Lipid Classification and Nomenclature Committee under the sponsorship of the LIPID MAPS Consortium developed and established a “Comprehensive Classification System for Lipids” based on well-defined chemical and biochemical principles and using an ontology that is extensible, flexible, and scalable. This classification system, which is compatible with contemporary databasing and informatics needs, has now been accepted internationally and widely adopted. In response to considerable attention and requests from lipid researchers from around the globe and in a variety of fields, the comprehensive classification system has undergone significant revisions over the last few years to more fully represent lipid structures from a wider variety of sources and to provide additional levels of detail as necessary. The details of this classification system are reviewed and updated and are presented here, along with revisions to its suggested nomenclature and structure-drawing recommendations for lipids.

Fahy, Eoin; Subramaniam, Shankar; Murphy, Robert C.; Nishijima, Masahiro; Raetz, Christian R. H.; Shimizu, Takao; Spener, Friedrich; van Meer, Gerrit; Wakelam, Michael J. O.; Dennis, Edward A.



Adipose differentiation related protein induces lipid accumulation and lipid droplet formation in hepatic stellate cells  

Microsoft Academic Search

Summary  The function of adipose differentiation-related protein (ADRP) is known to be the uptake of long-chain fatty acids and formation\\u000a of lipid droplets in lipid-accumulating cells. We hypothesized that ADRP might stimulate activated hepatic stellate cells\\u000a (HSCs) to accumulate lipids, resulting in their transition to the quiescent state. In this study, cultured HSCs in fifth passages\\u000a isolated from rat were infected

Marie Fukushima; Munechika Enjoji; Motoyuki Kohjima; Rie Sugimoto; Satoshi Ohta; Kazuhiro Kotoh; Masami Kuniyoshi; Kunihisa Kobayashi; Minako Imamura; Toyoshi Inoguchi; Makoto Nakamuta; Hajime Nawata



Effect of Polyacrylic Acid on Phase State of Lipids and Diffusion in Lipid-Water System  

Microsoft Academic Search

.  Lipid vesicles interacting with polyanions are promising for controlled drug delivery. However, different aspects of the interaction\\u000a of these polymers with lipids are far from complete understanding. In this work we studied the influence of polyacrylic acid\\u000a (PAA) with small concentrations (1–4 mol%) on the change of the phase state, lateral diffusion of these lipids in lamellar\\u000a phase and transmembrane

A. Filippov; A. Suleymanova; A. Berkovich



Extension of the GLYCAM06 biomolecular force field to lipids, lipid bilayers and glycolipids  

Microsoft Academic Search

GLYCAM06 is a generalisable biomolecular force field that is extendible to diverse molecular classes in the spirit of a small-molecule force field. Here we report parameters for lipids, lipid bilayers and glycolipids for use with GLYCAM06. Only three lipid-specific atom types have been introduced, in keeping with the general philosophy of transferable parameter development. Bond stretching, angle bending, and torsional

M. B. Tessier; M. L. DeMarco; A. B. Yongye; R. J. Woods



STKE Focus Issue on Lipid Biology: Lipids, Partners in Cellular Signaling  

NSDL National Science Digital Library

This week's issue of Science features a special section called Lipid Biology (;294/5548/1861) that highlights some of the complex and intriguing roles of lipids in numerous processes, including cellular lipid homeostasis, inflammation, vesicle trafficking, angiogenesis, and developmental biology. The diverse nature of these molecules underscores the variety of signaling scenarios in which these molecules participate.

Lisa D. Chong (the American Association for the Advancement of Science;Associate Editor of Science's STKE and Science REV)



Combination of antitumor ether lipid with lipids of complementary molecular shape reduces its hemolytic activity  

Microsoft Academic Search

Because the therapeutic use of the antitumor ether lipid 1-O-octadecyl-2-O-methyl-sn-glycero-3-phosphorylcholine (ET-18-OCH3) is restricted by its hemolytic activity we explored the use of lipid packing parameters to reduce this toxicity by creating structurally optimized ET-18-OCH3 liposomes. We postulated that combination of ET-18-OCH3, which is similar in structure to lysophosphatidylcholine, with lipid molecules of complementary molecular shape (opposite headgroup\\/chain volume) would likely

Walter R Perkins; Richard B Dause; Xingong Li; J. Craig Franklin; Donna J Cabral-Lilly; Yan Zha; Eugene H Dank; Eric Mayhew; Andrew S Janoff



Supported lipid bilayer/carbon nanotube hybrids  

NASA Astrophysics Data System (ADS)

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

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



Lymphatic lipid transport: sewer or subway?  


The lymphatics began receiving attention in the scientific community as early as 1622, when Gasparo Aselli noted the appearance of milky-white vessels in the mesentery of a well-fed dog. Since this time, the lymphatic system has been historically regarded as the sewer of the vasculature, passively draining fluid and proteins from the interstitial spaces (along with lipid from the gut) into the blood. Recent reports, however, suggest that the lymphatic role in lipid transport is an active and intricate process, and that when lymphatic function is compromised, there are systemic consequences to lipid metabolism and transport. This review highlights these recent findings, and suggests future directions for understanding the interplay between lymphatic and lipid biology in health and disease. PMID:20541951

Dixon, J Brandon



Induction of macrophage growth by lipids  

SciTech Connect

Lipoproteins from ascitic tumors in mice and lipids extracted from these lipoproteins induced growth of murine peritoneal macrophages in vitro. The lipid components with activity were examined by use of lipid vesicles or liposomes. Liposomes prepared from egg-yolk PC alone did not induce macrophage growth, but those prepared from mixtures of egg-yolk PC and cholesterol or cholesteryl esters other than cholesteryl oleate, or triglycerides other than triolein, enhanced /sup 3/H-TdR incorporation into macrophages. The free fatty acids examined had no effect on /sup 3/H-TdR incorporation. These results suggest that growth of macrophages is induced by ordinary lipids present in lipoproteins or cell membranes that the macrophages scavenge in the body.

Yui, S.; Yamazaki, M.



Rosiglitazone and Fenofibrate Additive Effects on Lipids.  

National Technical Information Service (NTIS)

To evaluate the effect of rosiglitazone, fenofibrate, or their combined use on plasma lipids in normoglycemic healthy adults.Methods and Results. Subjects were randomized in a double-blind fashion to rosiglitazone + placebo, fenofibrate + placebo, rosigli...

A. Slim D. P. Moore E. Hulten J. N. Slim L. Castillo-Rojas



The cornea and disorders of lipid metabolism.  


Disorders of lipid metabolism, either hyperlipidemia or hypolipidemia, are associated with the formation of corneal opacities. Corneal arcus, the most commonly encountered peripheral corneal opacity, is frequently associated with abnormal serum lipid levels, but may occur without any predisposing factors. Reports also have linked corneal arcus with alcoholism, diabetes mellitus and atherosclerotic heart disease. Unilateral arcus is a rare entity that is associated with carotid artery disease or ocular hypotony. Diffuse corneal opacities associated with hypolipidemic disorders such as LCAT deficiency, fish eye disease and Tangier disease, may be the initial manifestation of these disorders and puts the ophthalmologist in a position to make an early diagnosis. Corneal arcus, along with a central corneal opacity, is seen in Schnyder's crystalline stromal distrophy. The association of the disorder with a dyslipidemia remains controversial. A review of lipid metabolism, corneal arcus and several disorders of lipid metabolism that affect the cornea are presented. PMID:1925941

Barchiesi, B J; Eckel, R H; Ellis, P P


Interaction of Lipids with Inert Gases.  

National Technical Information Service (NTIS)

The role of lipid peroxidation in the induction of disease has been elaborated upon in this report, with examples such as multiple sclerosis and vitamin E deficiency. Autoxidation of the methyl esters of linoleic acid are appreciably different in various ...

H. S. Mickel



Cooperative Motion in Lipid Bilayer Membranes  

NASA Astrophysics Data System (ADS)

Lipid bilayer membranes, like the cell membrane, are complex biological systems. Transport of specific molecules in and out of cells are controlled by these membranes. Therefore, it is vital to understand the detailed dynamics that ultimately control membrane transport. We use molecular dynamics simulations of a coarse-grained and solvent-free lipid model that has been previously shown to spontaneously assemble a bilayer structure. Approaching the crossover to the gel-like state of the bilayer, the lipid dynamics become extremely slow. We analyze the cooperativity of the lipid motion and compare it with the cooperativity that has been well-characterized in liquids nearing a glass transition. Future simulations will examine the generality of this behavior using more realistic models, and comparing with experiments.

Hartmann, Benedikt; Starr, Francis



Analysis of lipid particles from yeast.  


Quantitative analysis of components from different subcellular fractions is a key to the understanding of metabolic function as well as to the origin, the biogenesis, and the crosstalk of organelles. The yeast is an excellent model organism to address such questions from the biochemical, molecular biological, and cell biological viewpoints. A yeast organelle which gained much interest during the last decade is the lipid particle/droplet (LP), a storage compartment for nonpolar lipids but at the same time an organelle actively contributing to cellular metabolism. In this chapter, we describe methods and techniques that are commonly used to analyze lipids from LP at the molecular level by thin-layer chromatography, gas-liquid chromatography, and mass spectrometry. We provide an easy to follow guideline for the isolation of these organelles, the qualitative and quantitative analysis of lipid components and show results obtained with these methods. PMID:19763485

Connerth, Melanie; Grillitsch, Karlheinz; Köfeler, Harald; Daum, Günther



Lipid rafts: heterogeneity on the high seas.  

PubMed Central

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.

Pike, Linda J



Lymphatic Lipid Transport: Sewer or Subway?  

PubMed Central

The lymphatics began receiving attention in the scientific community as early as 1622, when Gasparo Aselli noted the appearance of milky white vessels in the mesentery of a well-fed dog. Since this time, the lymphatic system has been historically regarded as the sewer of the vasculature, passively draining fluid and proteins from the interstitial spaces (along with lipid from the gut) into the blood. Recent reports, however, suggest that the lymphatic role in lipid transport is an active and intricate process and when lymphatic function is compromised, there are systemic consequences to lipid metabolism and transport. This review highlights these recent findings and suggests future directions for understanding the interplay between lymphatic and lipid biology in health and disease.

Dixon, J. Brandon



Preliminary Studies in Marine Lipid Oxidation.  

National Technical Information Service (NTIS)

Published information on current concepts of lipid oxidation mechanisms, oxidation products and their measurement by chemical and chromatographic means are reviewed. Strengths and weaknesses of classical methodology are discussed in some detail. Recently ...

J. D. Joseph G. T. Seaborn



Lipids and the endothelium: bidirectional interactions.  


The endothelium is often viewed solely as the barrier that prevents the penetration of circulating lipoproteins into the arterial wall. However, recent research has demonstrated that the endothelium has an important part in regulating circulating fatty acids and lipoproteins, and is in turn affected by these lipids/lipoproteins in ways that appear to have important repercussions for atherosclerosis. Thus, a number of potentially toxic lipids are produced during lipolysis of lipoproteins at the endothelial cell surface. Catabolism of triglyceride-rich lipoproteins creates free fatty acids that are readily taken up by endothelial cells, and, likely through the action of acyl-CoA synthetases, exacerbate inflammatory processes. In this article, we review how the endothelium participates in lipoprotein metabolism, how lipids alter endothelial functions, and how lipids are internalized, processed, and transported into the subendothelial space. Finally, we address the many endothelial changes that might promote atherogenesis, especially in the setting of diabetes. PMID:24037142

Goldberg, Ira J; Bornfeldt, Karin E



Role of epoxide hydrolases in lipid metabolism.  


Epoxide hydrolases (EH), enzymes present in all living organisms, transform epoxide-containing lipids to 1,2-diols by the addition of a molecule of water. Many of these oxygenated lipid substrates have potent biological activities: host defense, control of development, regulation of blood pressure, inflammation, and pain. In general, the bioactivity of these natural epoxides is significantly reduced upon metabolism to diols. Thus, through the regulation of the titer of lipid epoxides, EHs have important and diverse biological roles with profound effects on the physiological state of the host organism. This review will discuss the biological activity of key lipid epoxides in mammals. In addition, the use of EH specific inhibitors will be highlighted as possible therapeutic disease interventions. PMID:22722082

Morisseau, Christophe



Covalently Bound Lipids of Human Stratum Corneum  

Microsoft Academic Search

In the present study, we demonstrate that human stratum corneum contains covalently bound lipids accounting for 1.4% of the dry weight of the tissue. The major component (53.3% of the total by weight) is a ceramide (CER-A) consisting of 30 through 34-carbon ?-hydroxyacids amide-linked to sphingosine. The other hound lipids in human stratum corneum include fatty acids (12.7%), ?-hydroxy acids

Philip W. Wertz; Kathi C. Madison; Donald T. Downing



Lipids and buoyancy in Southern Ocean pteropods  

Microsoft Academic Search

The lipids of Clione limacina, a Southern Ocean pteropod (order Gymnosomata), contain 28% diacylglyceryl ether (DAGE) (as percentage of total lipid) whereas\\u000a the pteropod Limacina helicina (order Thecosomata) lacks DAGE. The alkyl glyceryl ether diols (1-O-alkyl glycerols, GE) of Clione DAGE are dominated by 16?0 (60%) and 15?0 (21%), in contrast with deep-sea shark liver DAGE, which is dominated by

Charles F. Phleger; Peter D. Nichols; Patti Virtue



Human milk in disease: Lipid Composition  

Microsoft Academic Search

Differences in the lipid composition of human milk have been described in maternal diseases known to affect fat metabolism.\\u000a Diseases such as diabetes, cystic fibrosis, hypobetalipoproteinemia and Type I hyperlipoproteinemia affect the quantity and\\u000a quality of human milk fat. Increased fatty acid chain elongation and changes in desaturation (especially ?6 desaturase), as\\u000a well as changes in lipid class composition, have

Margit Hamosha; Joel Bitman



Hedgehog Signaling: A Tale of Two Lipids  

NSDL National Science Digital Library

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.

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



Membrane Cholesterol, Protein Phosphorylation, and Lipid Rafts  

NSDL National Science Digital Library

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.

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



Aluminum Enhances Melanin-Induced Lipid Peroxidation  

Microsoft Academic Search

The present study was conducted to characterize the possible interaction of Al3+ and Fe2+ with synthetic melanin in the potentiation of lipid peroxidation in liposomes and rat caudate-putamen homogenates. Al3+ stimulated melanin-initiated lipid peroxidation as measured by the production of 2-thiobarbituric acid-reactive substances (TBARS) and conjugated dienes. The effect of Al3+ was dependent on melanin (10–100 µg\\/ml) and Al3+ (2.5–250

Leonardo Meglio; Patricia I. Oteiza



Pediatric aspects of lipid-induced atherogenesis.  


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

Kannel, W B



Lipid biosynthesis in cultures of oilseed rape  

Microsoft Academic Search

Summary  This review focuses on how microspore-derived (MD) embros and cell suspension cultures of oilseed rape have been used to advance\\u000a our understanding of the biochemistry and molecular biology of lipid biosynthesis in plants. Both types of cultures are easily\\u000a maintained and circumvent the difficulties associated with using developing seeds for investigations of lipid biosynthesis.\\u000a Developing MD embryos exhibit a similar

Randall J. Weselake



Lipid composition of millet ( Pennisetum americanum ) seeds  

Microsoft Academic Search

The composition of lipids extracted from a sample of millet seeds by each of 8 solvent systems is reported. Lipid components\\u000a were separated by silicic acid column and thin layer chromatography (TLC) and quantitated by analysis of fatty acid methyl\\u000a esters by gas liquid chromatography (GLC), with heptadecanoic acid as internal standard. Best results were obtained by extraction\\u000a with hot

A. U. Osagie; M. Kates



Blood lipids in young distance runners  

Microsoft Academic Search

EISENMANN, J. C., C. J. WOMACK, M. J. REEVES, J. M. PIVARNIK, and R. M. MALINA. Blood lipids in young distance runners. Med. Sci. Sports Exerc., Vol. 33, No. 10, 2001, pp. 1661-1666. Purpose: The purpose of this study was to examine the age-and sex-associated variation in blood lipids among young athletes. Methods: A mixed-longitudinal design was used to examine




Biosynthesis and biotransformation of ether lipids  

Microsoft Academic Search

Some naturally occurring as well as synthetic ether lipids are biologically active. In certain cases, the effects of these\\u000a substances are enhanced, in others, they are inhibited by compounds that were isolated from natural sources or prepared by\\u000a chemical synthesis. The biotrans-formation of natural or “unnatural” ether lipids in microorganisms, plant or animal tissue\\u000a also can lead to substances that

Helmut K. Mangold; Nikolaus Weber



A Role for Lipid Shells in Targeting Proteins to Caveolae, Rafts, and Other Lipid Domains  

NASA Astrophysics Data System (ADS)

The surface membrane of cells is studded with morphologically distinct regions, or domains, like microvilli, cell-cell junctions, and coated pits. Each of these domains is specialized for a particular function, such as nutrient absorption, cell-cell communication, and endocytosis. Lipid domains, which include caveolae and rafts, are one of the least understood membrane domains. These domains are high in cholesterol and sphingolipids, have a light buoyant density, and function in both endocytosis and cell signaling. A major mystery, however, is how resident molecules are targeted to lipid domains. Here, we propose that the molecular address for proteins targeted to lipid domains is a lipid shell.

Anderson, Richard G. W.; Jacobson, Ken



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

PubMed Central

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

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



Lipids distribution imaging of lipid vesicles by multi-focus excitation CARS microscope  

NASA Astrophysics Data System (ADS)

We demonstrated high-speed imaging of the distribution of DPPC (dipalmitoylphosphatidylcholine), d62-DPPC (deuterated DPPC), and DOPC (dioleoylphosphatidylcholine) lipids in a lipid vesicle with a multi-focus excitation CARS (coherent anti-Stokes Raman scattering) microscope using a microlens array scanner. By the multi-focus excitation, the dwell time is increased in proportion to the number of focal spots compared with a single beam scanning, and high-speed and high-quality CARS imaging is possible without increasing the peak power of each spot. We demonstrated the selectively visualization of DPPC and d62-DPPC lipid vesicles, in which the vesicles contain a type of lipid, by observing at 2840 cm-1 and 2090 cm-1. We also visualized the DOPC and DPPC lipids distribution in a lipid mixture vesicle observed at 1440 cm-1 and 1655 cm-1. The image acquisition time of 10 s/image at each Raman shift was realized. The signal ratio of 1440 cm-1 and 1655 cm-1 was locally intense on the lipid vesicle. It must be because the gel phase domain of DPPC lipids was exists in the DOPC lipids which were liquid-crystalline phase at room temperature.

Minamikawa, Takeo; Araki, Tsutomu; Hashimoto, Mamoru



Ionic liquid-mediated extraction of lipids from algal biomass  

Microsoft Academic Search

Lipids from algal biomass were extracted using mixtures of ionic liquids (ILs) and methanol, and fatty acid profiles of the extracted lipids were characterized in this work. Mixtures of ILs and methanol successfully dissolved biomass leaving lipids insoluble. The total contents of lipids extracted from commercial and cultivated Chlorella vulgaris were 10.6% and 11.1%, respectively, by the conventional Bligh and

Young-Hoo Kim; Yong-Keun Choi; Seongmin Lee; Yung-Hun Yang; Hyung Joo Kim; Tae-Joon Park; Yong Hwan Kim; Sang Hyun Lee


Prediction of Body Lipid Change in Pregnancy and Lactation  

Microsoft Academic Search

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

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



A multivitamin infusion prevents lipid peroxidation and improves transplantation performance  

Microsoft Academic Search

A multivitamin infusion prevents lipid peroxidation and improves transplantation performance. The objective of this study was to test the hypothesis that ischemia reperfusion damage in kidney transplantation is associated with lipid peroxidation and that inhibition of lipid peroxidation by antioxidants improves the function of the transplanted kidney. Lipid peroxidation was assessed by measuring the plasma malonaldehyde content (as thiobarbituric acid

Hans Rabl; Gholamali Khoschsorur; Thomas Colombo; Peter Petritsch; Michael Rauchenwald; Peter Költringer; Franz Tatzber; Hermann Esterbauer



The Role of Lipids in Determining Spaghetti Cooking Quality  

Microsoft Academic Search

Cereal Chem. 63(6):484-489 Durum semolina nonpolar lipids influence surface stickiness of procedure did not influence amylograph characteristics or spaghetti microprocessed cooked spaghetti. Removal of nonpolar lipids with quality. Some effects of lipids on farinograph characteristics were found, petroleum ether increases stickiness, whereas nonpolar lipid enrichment but these changes were not related to any of the cooking quality parameters. decreases stickiness.



Elasticities and stabilities: lipid membranes vs cell membranes  

Microsoft Academic Search

A cell membrane can be simply regarded as composite material consisting of lipid bilayer, membrane cytoskeleton beneath lipid bilayer, and proteins embedded in lipid bilayer and linked with membrane cytoskeleton if one only concerns its mechanical properties. In this Chapter, above all, the authors give a brief introduction to some important work on mechanical properties of lipid bilayers following Helfrich's

Z. C. Tu; R. An; Z. C. Ou-Yang



Lipids of Branhamella catarrhalis and Neisseria gonorrhoeae.  

PubMed Central

Three strains of Branhamella catarrhalis and three strains of Neisseria gonorrhoeae were analyzed with regard to their phospholipid and neutral lipid composition. B. catarrhalis (ATCC 23246) contained 5.12 +/- 0.34% lipid, determined gravimetrically, compared to 8.56 +/- 0.15% and 9.73 +/- 0.06% for two strains of N. gonorrhoeae. Cardiolipin, phosphatidylglycerol, and phosphatidyl-ethanolamine were identified in extracts of both species. In addition, B. catarrhalis contained small amounts of phosphatidylcholine, and N. gonorrhoeae contained small amounts of lyso-phosphatidylethanolamine, which accumulated with autolysis accompanying late cell culture growth. The kinetics of change of relative amounts of phospholipids in both species were measured and found to differ substantially. Neutral lipid accounted for 30.4% of the total lipid of B. catarrhalis (ATCC 23246) and 7.6% of the total lipid of N. gonorrhoeae NYH 002. Hydrocarbons, triglycerides, free fatty acids, coenzyme Q, diglycerides, and free hydroxy fatty acids were identified in the neutral lipid fraction of both species. The three strains of N. gonorrhoeae, sensitive, intermediate, and resistant to penicillin, exhibited no significant difference in the composition or metabolism of phospholipid. Images

Beebe, J L; Wlodkowski, T J



Persistence of virus lipid signatures upon silicification  

NASA Astrophysics Data System (ADS)

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

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



Partial molecular volumes of lipids and cholesterol  

PubMed Central

Volumetric measurements are reported for fully hydrated lipid/cholesterol bilayer mixtures using the neutral flotation method. Apparent specific volume data were obtained with the lipids DOPC, POPC and DMPC at T = 30 °C, DPPC at 50 °C, and brain sphingomyelin (BSM) at 45 and 24 °C for mole fractions of cholesterol x from 0 to 0.5. Unlike previous cholesterol mixture studies, we converted our raw data to partial molecular volume VL of the lipid and VC of the cholesterol. The partial molecular volumes were constant for POPC and DOPC as x was varied, but had sharp breaks for the other lipids at values of xC near 0.25 ± 0.05. Results for x < xC clearly exhibit the condensation effect of cholesterol on DPPC, DMPC and BSM when measured at temperatures above their main transition temperatures TM. The break points at xC are compared to phase diagrams in the literature. For x > xC the values of the partial molecular volumes of cholesterol clustered near 630 ± 10 Å3 in all the lipids when measured for T > TM; we suggest that this is the most appropriate measure of the bare volume of cholesterol in lipid bilayers.

Greenwood, Alexander I.; Tristram-Nagle, Stephanie; Nagle, John F.




PubMed Central

DPP1-encoded and LPP1-encoded lipid phosphate phosphatases are integral membrane proteins in the yeast Saccharomyces cerevisiae. They catalyze the Mg2+-independent dephosphorylation of bioactive lipid phosphate molecules such as diacylglycerol pyrophosphate and phosphatidate. These enzymes possess a three-domain lipid phosphatase motif that is localized to the hydrophilic surface of the membrane. The lipid phosphate phosphatase activities of DPP1-encoded and LPP1-encoded enzymes are measured by following the release of water-soluble radioactive inorganic phosphate from chloroform-soluble radioactive lipid phosphate substrate following a chloroform/methanol/water phase partition. The DPP1-encoded enzyme, commonly referred to as diacylglycerol pyrophosphate phosphatase, is purified from wild-type S. cerevisiae membranes by detergent solubilization with Triton X-100 followed by chromatography with DEAE-cellulose (DE53), Affi-Gel blue, hydroxylapatite, and Mono Q. The purification scheme yields an essentially homogeneous enzyme preparation that is stable for several years upon storage at ?80°. The properties of the DPP1-encoded and LPP1-encoded lipid phosphate phosphatase enzymes are summarized.

Carman, George M.; Wu, Wen-I



Interaction of C(60) fullerene with lipids.  


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

Cataldo, Franco



CD36 as a lipid sensor.  


CD36 is a multifunctional protein homologous to the class B scavenger receptor SR-B1 mainly found in tissues with a sustained lipid metabolism and in several hematopoieic cells. CD36 is thought to be involved in various physiological and pathological processes like angiogenesis, thrombosis, atherogenesis, Alzheimer's disease or malaria. An additive emerging function for CD36 is a role as a lipid sensor. Location of CD36 and orthologue molecules in plasma membrane of cells in contact with the external environment (e.g. gustatory, intestinal or olfactory epithelia) allows the binding of exogenous-derived ligands including dietary lipids, diglycerides from bacterial wall in mammals and even a lipid-like pheromone in insects. Similar function might also exist in the brain in which a CD36-dependent sensing of fatty acids has been reported in ventromedial hypothalamic neurons in rodents. Specific recognition of lipid-related molecules by a receptor-like protein highly conserved throughout the evolution strongly suggests that lipid-sensing by CD36 is responsible for basic physiological functions in relation with behavior, energy balance and innate immunity. PMID:21354192

Martin, Céline; Chevrot, Michael; Poirier, Hélène; Passilly-Degrace, Patricia; Niot, Isabelle; Besnard, Philippe



Unclassified glioneuronal tumor with advanced lipidization.  


Lipidization is observed only occasionally in primary neuroectodermal tumors of the central nervous system. It may reflect lipomatous transformation of tumor cells into xanthomatous and/or adipocyte-like cells. We report a unique case of mixed glioneuronal tumor with marked lipomatous changes in a young patient with intractable epilepsy. MRI revealed a well-circumscribed lesion in the right temporal lobe. Histopathological findings showed the pleomorphic tumor with numerous cells containing large lipid droplets, resembling mature adipocytes, that were arranged in clusters or scattered within the neoplastic tissue. The tumor was composed of both glial and neuronal elements. Some tumor cells displayed features intermediate between glial and neuronal cells. The reticulin fibers were limited to blood vessels. Mitotic figures, vascular proliferation, and necrosis were absent, and MIB-1 labeling index was less than 1%. Diffuse immunoreactivity for GFAP and S100-protein was observed. In some heavily lipidized cells, the lipid droplets were surrounded by a cytoplasmic rim of GFAP immunoreactivity. Numerous cells exhibited immunostaining for NSE and synaptophysin. This is the first documented case of glioneuronal tumor with extensive lipomatous transformation, which might be considered as a heavily lipidized unclassified pleomorphic glioneuronal tumor or a variant of lipoganglioglioma with marked pleomorphism and severe lipidization. PMID:21562835

Matyja, Ewa; Grajkowska, Wies?awa; Kunert, Przemyslaw; Rysz, Andrzej; Marchel, Andrzej



Bending and Puncturing the Influenza Lipid Envelope  

PubMed Central

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

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



Cholecystokinin elevates mouse plasma lipids.  


Cholecystokinin (CCK) is a peptide hormone that induces bile release into the intestinal lumen which in turn aids in fat digestion and absorption in the intestine. While excretion of bile acids and cholesterol into the feces eliminates cholesterol from the body, this report examined the effect of CCK on increasing plasma cholesterol and triglycerides in mice. Our data demonstrated that intravenous injection of [Thr28, Nle31]-CCK at a dose of 50 ng/kg significantly increased plasma triglyceride and cholesterol levels by 22 and 31%, respectively, in fasting low-density lipoprotein receptor knockout (LDLR(-/-)) mice. The same dose of [Thr28, Nle31]-CCK induced 6 and 13% increases in plasma triglyceride and cholesterol, respectively, in wild-type mice. However, these particular before and after CCK treatment values did not achieve statistical significance. Oral feeding of olive oil further elevated plasma triglycerides, but did not alter plasma cholesterol levels in CCK-treated mice. The increased plasma cholesterol in CCK-treated mice was distributed in very-low, low and high density lipoproteins (VLDL, LDL and HDL) with less of an increase in HDL. Correspondingly, the plasma apolipoprotein (apo) B48, B100, apoE and apoAI levels were significantly higher in the CCK-treated mice than in untreated control mice. Ligation of the bile duct, blocking CCK receptors with proglumide or inhibition of Niemann-Pick C1 Like 1 transporter with ezetimibe reduced the hypercholesterolemic effect of [Thr28, Nle31]-CCK in LDLR(-/-) mice. These findings suggest that CCK-increased plasma cholesterol and triglycerides as a result of the reabsorption of biliary lipids from the intestine. PMID:23300532

Zhou, Lichun; Yang, Hong; Lin, Xinghua; Okoro, Emmanuel U; Guo, Zhongmao



Apparent digestion and apparent retention of lipid and fatty acids in Atlantic cod ( Gadus morhua) fed increasing dietary lipid levels  

Microsoft Academic Search

The aim of the present study was to investigate how different dietary lipid levels affect growth, liver lipid deposition, apparent digestibility, apparent retention and utilization of total lipid and fatty acids in Atlantic cod. Individually tagged cod, with an average weight of 360 g, were randomly distributed in nine tanks, 49 fish per tank. Five diets with increasing dietary lipid level

Jon Øvrum Hansen; Gerd Marit Berge; Marie Hillestad; Åshild Krogdahl; Trina F. Galloway; Halvor Holm; Jørgen Holm; Bente Ruyter



Effect of dietary lipid level on growth performance, lipid deposition, hepatic lipogenesis in juvenile cobia ( Rachycentron canadum)  

Microsoft Academic Search

A study was undertaken to evaluate the effect of the dietary lipid level on growth, feed utilization, lipid deposition and lipid metabolism by cobia juveniles. Three isonitrogenous diets containing 47% crude protein with increasing dietary lipid levels 5%, 15% and 25% (DM, dry matter) were fed to satiety to triplicate groups of 20 fish (7.71 g) for 6 weeks. At

Ji-Teng Wang; Yong-Jian Liu; Li-Xia Tian; Kang-Sen Mai; Zhen-Yu Du; Yong Wang; Hui-Jun Yang



Composition, accumulation and utilization of yolk lipids in teleost fish  

Microsoft Academic Search

Lipid reserves in teleost eggs are stored in lipoprotein yolk and, in some species, a discrete oil globule. Lipoprotein yolk lipids are primarily polar lipids, especially phosphatidylcholine and phosphatidylethanolamine (PE), and are rich in (n-3) polyunsaturated fatty acids, especially 22:6(n-3) (docosahexaenoic acid, DHA). Oil consists of neutral lipids and is rich in monounsaturated fatty acids (MUFA). Egg lipids are derived

Murray D. Wiegand



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


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

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



Bright Ion Channels and Lipid Bilayers.  


If we look at a simple organism such as a zebrafish under a microscope, we would see many cells working in harmony. If we zoomed in, we would observe each unit performing its own tasks in a special aqueous environment isolated from the other units by a lipid bilayer approximately 5 nm thick. These confined units are social: they communicate with one another by sensing and responding to the chemical changes in their environment through receptors and ion channels. These channels control the highly specific and selective passage of ions from one side of the cell to the other and are embedded in lipid bilayers. The movement of ions through ion channels supports excitation and electrical signaling in the nervous system. Ion channels have fascinated scientists not only because of their specificity and selectivity, but also for their functions, the serious consequences when they malfunction, and the other potential applications of these molecules. Light is a useful trigger to control and manipulate ion channels externally. With the many state-of-the-art optical technologies available, light offers a high degree of spatial and temporal control, millisecond precision, and noninvasive intervention and does not change the chemical environment of the system of interest. In this Account, we discuss research toward the dynamic control of lipid bilayer assembly and channel function, particularly the transport across the lipid bilayer-ion channel barrier of cells using light. We first summarize the manipulation of ion channel activity with light to modulate the channel's natural activity. Based on the type of photoswitch employed, we can achieve novel functionalities with these channels, and control neural activity. Then we discuss the recent developments in light-induced transport through lipid bilayers. We focus on three different approaches: the incorporation of photoswitchable copolymers into the lipids, the doping of the lipid bilayer with photosensitive amphiphiles and the preparation of the lipid bilayers solely from photoswitchable lipids. These examples reflect the versatility of what we can achieve by manipulating biological systems with light, from triggering the permeability of a specific area of a lipid bilayer to controlling the behavior of a whole organism. PMID:23597020

Szyma?ski, Wiktor; Yilmaz, Duygu; Koçer, Arma?an; Feringa, Ben L



Lipid Bilayers Covalently Anchored to Carbon Nanotubes  

PubMed Central

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.

Dayani, Yasaman; Malmstadt, Noah



Lipid-Protein Interaction During Aqueous Extraction of Fish Protein: Myosin-Lipid Interaction.  

National Technical Information Service (NTIS)

The paper presents the results of model system experiments to determine whether or not fish lipid interacts with myosin and which groups of lipids are responsible for this interaction. Studies on the effect of aging, heating and air denaturation (foam for...

S. Y. K. Shenouda G. M. Pigott



Designing biorelevant dissolution tests for lipid formulations: Case example – Lipid suspension of RZ-50  

Microsoft Academic Search

Biorelevant dissolution test methods for lipid formulations of RZ-50, an experimental Roche compound, were developed and compared with standard compendial methods in terms of their in vivo predictability. Release of RZ-50, a poorly soluble weakly acidic drug, from lipid suspensions filled in soft gelatin capsules was studied in compendial and biorelevant media using the USP Apparatus 2 (paddle method) and

Ekarat Jantratid; Niels Janssen; Hitesh Chokshi; Kin Tang; Jennifer B. Dressman



Perinatal expression of genes that may participate in lipid metabolism by lipid-laden lung fibroblasts  

Microsoft Academic Search

Although a morphologically distinct population of lipid-laden interstitial cells (lipofibroblasts, LF), has been identified, the origins and functions of this population dur- ing lung development and disease remain undefined. Illu- mination of the developmental and functional characteris- tics of two other populations of lipid-laden mesenchymal cells, namely adipocytes and hepatic lipocytes, has fash- ioned tools that can be used to

Heshun Chen; Sheila Jackson; Melissa Doro; Stephen McGowan


Orphan enzymes in ether lipid metabolism.  


Ether lipids are an emerging class of lipids which have so far not been investigated and understood in every detail. They have important roles as membrane components of e.g. lens, brain and testis, and as mediators such as platelet-activating factor. The metabolic enzymes for biosynthesis and degradation have been investigated to some extent. As most involved enzymes are integral membrane proteins they are tricky to handle in biochemical protocols. The sequence of some ether lipid metabolising enzymes has only recently been reported and other sequences still remain obscure. Defined enzymes without assigned sequence are known as orphan enzymes. One of these enzymes with uncharacterised sequence is plasmanylethanolamine desaturase, a key enzyme for the biosynthesis of one of the most abundant phospholipids in our body, the plasmalogens. This review aims to briefly summarise known functions of ether lipids, give an overview on their metabolism including the most prominent members, platelet-activating factor and the plasmalogens. A special focus is set on the description of orphan enzymes in ether lipid metabolism and on the successful strategies how four previous orphans have recently been assigned a sequence. Only one of these four was characterised by classical protein purification and sequencing, whereas the other three required alternative strategies such as bioinformatic candidate gene selection and recombinant expression or development of an inhibitor and multidimensional metabolic profiling. PMID:22771767

Watschinger, Katrin; Werner, Ernst R



Orphan enzymes in ether lipid metabolism  

PubMed Central

Ether lipids are an emerging class of lipids which have so far not been investigated and understood in every detail. They have important roles as membrane components of e.g. lens, brain and testis, and as mediators such as platelet-activating factor. The metabolic enzymes for biosynthesis and degradation have been investigated to some extent. As most involved enzymes are integral membrane proteins they are tricky to handle in biochemical protocols. The sequence of some ether lipid metabolising enzymes has only recently been reported and other sequences still remain obscure. Defined enzymes without assigned sequence are known as orphan enzymes. One of these enzymes with uncharacterised sequence is plasmanylethanolamine desaturase, a key enzyme for the biosynthesis of one of the most abundant phospholipids in our body, the plasmalogens. This review aims to briefly summarise known functions of ether lipids, give an overview on their metabolism including the most prominent members, platelet-activating factor and the plasmalogens. A special focus is set on the description of orphan enzymes in ether lipid metabolism and on the successful strategies how four previous orphans have recently been assigned a sequence. Only one of these four was characterised by classical protein purification and sequencing, whereas the other three required alternative strategies such as bioinformatic candidate gene selection and recombinant expression or development of an inhibitor and multidimensional metabolic profiling.

Watschinger, Katrin; Werner, Ernst R.



Studies on mixed monolayers of phospholipids and fusogenic lipids.  

PubMed Central

1. The behaviour of mixed monolayers of 14 different lipids with preparations of erythrocyte lipids, purified natural and synthetic phospholipids, cholesterol and galactosylceramide was investigated. 2. The mean areas occupied per molecule in mixed films containing lipids that are fusogenic for hen erythrocytes were compared with those for corresponding films containing lipids that are inactive as fusogens. 3. Fusogenic lipids were found to exhibit interactions, which were not shown by non-fusogenic lipids, in mixed monolayers with several species of phospholipid, particularly those containing a choline head group. 4. Heterogeneity in the hydrophobic chains of phosphatidylcholine, their degree of unsaturation and the presence of cholesterol had little effect on the interaction of phosphatidylcholine with fusogenic lipids. 5. Fusogenic lipids showed little specific interaction with natural or synthetic preparations of phosphatidylethanolamine. 6. The possible significance of these observations in relation to the action of fusogenic lipids on biological membranes is discussed in the light of the asymmetrical distribution of phospholipids in erythrocyte membranes.

Maggio, B; Lucy, J A



Lipid Bilayer Composition Affects Transmembrane Protein Orientation and Function  

PubMed Central

Sperm membranes change in structure and composition upon ejaculation to undergo capacitation, a molecular transformation which enables spermatozoa to undergo the acrosome reaction and be capable of fertilization. Changes to the membrane environment including lipid composition, specifically lipid microdomains, may be responsible for enabling capacitation. To study the effect of lipid environment on proteins, liposomes were created using lipids extracted from bull sperm membranes, with or without a protein (Na+ K+-ATPase or ?-amylase). Protein incorporation, function, and orientation were determined. Fluorescence resonance energy transfer (FRET) confirmed protein inclusion in the lipid bilayer, and protein function was confirmed using a colourometric assay of phosphate production from ATP cleavage. In the native lipid liposomes, ATPase was oriented with the ? subunit facing the outer leaflet, while changing the lipid composition to 50% native lipids and 50% exogenous lipids significantly altered this orientation of Na+ K+-ATPase within the membranes.

Hickey, Katie D.; Buhr, Mary M.



Multiscale Simulations Reveal Conserved Patterns of Lipid Interactions with Aquaporins  

PubMed Central

Summary Interactions of membrane proteins with lipid molecules are central to their stability and function. We have used multiscale molecular dynamics simulations to determine the extent to which interactions with lipids are conserved across the aquaporin (Aqp) family of membrane proteins. Simulation-based assessment of the lipid interactions made by Aqps when embedded within a simple phospholipid bilayer agrees well with the protein-lipid contacts determined by electron diffraction from 2D crystals. Extending this simulation-based analysis to all Aqps of known structure reveals a degree of conservation of such interactions across the Aqp structural proteome. Despite similarities in the binding orientations and interactions of the lipids, there do not appear to be distinct, high-specificity lipid binding sites on the surface of Aqps. Rather Aqps exhibit a more broadly conserved protein/lipid interface, suggestive of interchange between annular and bulk lipids, instead of a fixed annular “shell” of lipids.

Stansfeld, Phillip J.; Jefferys, Elizabeth E.; Sansom, Mark S.P.



Biosynthesis and function of plant lipids  

SciTech Connect

The Sixth Annual Symposium in Botany and Plant Physiology was held January 13-15, 1983, at the University of California, Riverside. This volume comprises the papers that were presented. Subjects discussed at the symposium covered a wide range in the field of plant lipids. Biosynthesis of lipids occupied an important fraction of the presentations at the symposium. Subjects included detailed studies of the enzymes of fatty acid synthesis, several discussions of the incorporation of fatty acids into glycerolipids and the further modification of the fatty acids, and the synthesis of glycerolipids and desaturation of fatty acids in both maturing oilseeds and chloroplasts. The physicochemical studies of glycerolipids and sterols in artificial membranes have led to distinct conclusions about their behaviour which must be relevant in the biological membrane. Results on the functional consequences of modifying the galactolipid composition in the chloroplast were an encouraging sign of progress in the attempts to relate membrane lipid composition to physiological function.

Thomson, W.W.; Mudd, J.B.; Gibbs, M. (eds.)



Lipids of a Sterol-Nonrequiring Mycoplasma  

PubMed Central

The lipids of the sterol nonrequiring Mycoplasma strain S743 were found to include both ester glycerophosphatides (phosphatidylglycerol, acylphosphatidylglycerol, and diphosphatidylglycerol) and ceramide glycerophosphate compounds containing N-hydroxyacyl groups. The major phosphosphingolipid was tentatively identified as a hydroxyceramidephosphorylglycerol containing an O-acyl group. These compounds became labeled during growth in the presence of 32P-orthophosphate, 14C-glycerol, or 14C-palmitate. The lipid fraction also contained free long-chain base. 14C-palmitate was converted to labeled sphinganine. The long-chain base composition of the lipids was modified by growing the organisms in media containing different fatty acids, which were converted to bases containing two more C atoms per molecule. Ninety per cent of the long-chain base from cells grown in medium supplemented with elaidate consisted of monounsaturated C20 base. Images

Plackett, P.; Smith, P. F.; Mayberry, W. R.



Lipid Catabolism of Relapsing Fever Borreliae  

PubMed Central

Relapsing fever borreliae require lipid compounds for growth in vitro. In this study, the major pathways of lipid catabolism in three species of tick-borne relapsing fever borreliae were investigated. Thin-layer chromatography was used to compare chloroform-methanol extracts of fresh culture media with extracts of exhausted culture media after organisms were removed by centrifugation. The chromatographic data demonstrated that lysolecithin was removed from the culture media during growth of the spirochetes, whereas lecithin, sphingomyelin, triglycerides, and cholesterol esters were not affected by growth of the organisms. Sonic extracts of the organism were tested for the presence of specific enzymes of lipid catabolism. Lysolecithinase, glycerophosphorylcholine diesterase, and acid phosphatase activities were demonstrated. Thus, these organisms can sequentially dissimilate lysolecithin to fatty acids, choline, inorganic phosphate, and glycerol. Assays for phospholipases A, C, and D, ?-glycerophosphate dehydrogenase, alkaline phosphatase, and lipase were negative. Images

Pickett, James; Kelly, Richard



Lipid peroxidation and mechanisms of toxicity.  


Aerobic organisms by definition require oxygen, and the importance of iron in aerobic respiration has long been recognized, but despite their beneficial roles, these elements can pose a real threat to the organism. During oxygen reduction, reactive species such as O2-. and H2O2 are formed readily. Iron can combine with these species, or with molecular oxygen itself, to generate free radicals which will attack the polyunsaturated fatty acids of membrane lipids. This oxidative deterioration of membrane lipids is known as lipid peroxidation. To protect itself against this form of attack, the organism possesses several types of defense mechanisms. Under normal conditions, these defenses appear to offer adequate protection for cell membranes, but the possibility exists that certain foreign compounds may interfere with or even overwhelm these defenses, and herein could lie a general mechanism of toxicity. This possible cause of toxicity is discussed in relation to other suggested causes. PMID:3311640

Horton, A A; Fairhurst, S



Apolipoprotein gene involved in lipid metabolism  


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.

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



ER Stress and Lipid Metabolism in Adipocytes  

PubMed Central

The role of endoplasmic reticulum (ER) stress is a rapidly emerging field of interest in the pathogenesis of metabolic diseases. Recent studies have shown that chronic activation of ER stress is closely linked to dysregulation of lipid metabolism in several metabolically important cells including hepatocytes, macrophages, ?-cells, and adipocytes. Adipocytes are one of the major cell types involved in the pathogenesis of the metabolic syndrome. Recent advances in dissecting the cellular and molecular mechanisms involved in the regulation of adipogenesis and lipid metabolism indicate that activation of ER stress plays a central role in regulating adipocyte function. In this paper, we discuss the current understanding of the potential role of ER stress in lipid metabolism in adipocytes. In addition, we touch upon the interaction of ER stress and autophagy as well as inflammation. Inhibition of ER stress has the potential of decreasing the pathology in adipose tissue that is seen with energy overbalance.

Zha, Beth S.; Zhou, Huiping



Geometric theory for adhering lipid vesicles.  


This paper aims at constructing a general mathematical model for the equilibrium theory of adhering lipid vesicles from a geometrical point of view. Based on the generalized potential functional, a few differential operators and their integral theorems on curved surfaces, the general normal and tangential equilibrium differential equations and boundary conditions are given at the first time for inhomogeneous lipid vesicles. A general boundary condition psi =square root (2(w-gamma/R)/k(c)) is first put forward including line tension. No assumptions are made either on the symmetry of the vesicle or on that of the substrate. The physical and biological meaning of the equilibrium differential equations and the boundary conditions are discussed. Numerical simulation results based on the Helfrich energy for adhering lipid vesicles under the axial symmetric condition show the effectiveness and convenience of the present theory. PMID:19643586

Lv, Cunjing; Yin, Yajun; Yin, Jie



Dengue virus induced autophagy regulates lipid metabolism  

PubMed Central

Summary Autophagy influences numerous cellular processes, including innate and adaptive immunity against intracellular pathogens. However, some viruses, including dengue virus (DENV), usurp autophagy to enhance their replication. The mechanism for a positive role of autophagy in DENV infection is unclear. We present data that DENV induction of autophagy regulates cellular lipid metabolism. DENV infection leads to an autophagy-dependent processing of lipid droplets and triglycerides to release free fatty acids. This results in an increase in cellular ?-oxidation, which generates ATP. These processes are required for efficient DENV replication. Importantly, exogenous fatty acids can supplant the requirement of autophagy in DENV replication. These results define a role for autophagy in DENV infection and provide a mechanism by which viruses can alter cellular lipid metabolism to promote their replication.

Heaton, Nicholas S.; Randall, Glenn



Peptide-Lipid Interactions: Experiments and Applications  

PubMed Central

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.

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



Lipid storage myopathy: successful treatment with propranolol.  

PubMed Central

Lipid storage myopathies are a rare but serious cause of muscle weakness characterised by the accumulation of abnormal amounts of neutral fat in type 1 fibres. A case is reported in which the patient presented with weakness of the proximal limb muscles and greatly increased activities of creatine kinase and lactate dehydrogenase. After two years lipid myopathy was diagnosed when electron microscopy confirmed the presence of large numbers of lipid particles within muscle fibres. Twelve years after the initial presentation propranolol (40 mg thrice daily) was started. Strength gradually improved and enzyme activities returned to normal. The improvement in the patient's condition was almost certainly due to the propranolol, although the mode of action of the drug remains unknown. Images FIG 1 FIG 2 FIG 3 FIG 4 FIG 6

Martyn, C; Jellinek, E H; Webb, J N



Assessing the Nature of Lipid Raft Membranes  

PubMed Central

The paradigm of biological membranes has recently gone through a major update. Instead of being fluid and homogeneous, recent studies suggest that membranes are characterized by transient domains with varying fluidity. In particular, a number of experimental studies have revealed the existence of highly ordered lateral domains rich in sphingomyelin and cholesterol (CHOL). These domains, called functional lipid rafts, have been suggested to take part in a variety of dynamic cellular processes such as membrane trafficking, signal transduction, and regulation of the activity of membrane proteins. However, despite the proposed importance of these domains, their properties, and even the precise nature of the lipid phases, have remained open issues mainly because the associated short time and length scales have posed a major challenge to experiments. In this work, we employ extensive atom-scale simulations to elucidate the properties of ternary raft mixtures with CHOL, palmitoylsphingomyelin (PSM), and palmitoyloleoylphosphatidylcholine. We simulate two bilayers of 1,024 lipids for 100 ns in the liquid-ordered phase and one system of the same size in the liquid-disordered phase. The studies provide evidence that the presence of PSM and CHOL in raft-like membranes leads to strongly packed and rigid bilayers. We also find that the simulated raft bilayers are characterized by nanoscale lateral heterogeneity, though the slow lateral diffusion renders the interpretation of the observed lateral heterogeneity more difficult. The findings reveal aspects of the role of favored (specific) lipid–lipid interactions within rafts and clarify the prominent role of CHOL in altering the properties of the membrane locally in its neighborhood. Also, we show that the presence of PSM and CHOL in rafts leads to intriguing lateral pressure profiles that are distinctly different from corresponding profiles in nonraft-like membranes. The results propose that the functioning of certain classes of membrane proteins is regulated by changes in the lateral pressure profile, which can be altered by a change in lipid content.

Niemela, Perttu S; Ollila, Samuli; Hyvonen, Marja T; Karttunen, Mikko; Vattulainen, Ilpo



Membrane protein dynamics: limited lipid control.  


Correlation of lipid disorder with membrane protein dynamics has been studied with infrared spectroscopy, by combining data characterizing lipid phase, protein structure and, via hydrogen-deuterium (H/D) exchange, protein dynamics. The key element was a new measuring scheme, by which the combined effects of time and temperature on the H/D exchange could be separated. Cyanobacterial and plant thylakoid membranes, mammalian mitochondria membranes, and for comparison, lysozyme were investigated. In dissolved lysozyme, as a function of temperature, H/D exchange involved only reversible movements (the secondary structure did not change considerably); heat-denaturing was a separate event at much higher temperature. Around the low-temperature functioning limit of the biomembranes, lipids affected protein dynamics since changes in fatty acyl chain disorders and H/D exchange exhibited certain correlation. H/D exchange remained low in all membranes over physiological temperatures. Around the high-temperature functioning limit of the membranes, the exchange rates became higher. When temperature was further increased, H/D exchange rates went over a maximum and afterwards decreased (due to full H/D exchange and/or protein denaturing). Maximal H/D exchange rate temperatures correlated neither with the disorder nor with the unsaturation of lipids. In membrane proteins, in contrast to lysozyme, the onsets of sizable H/D exchange rates were the onsets of irreversible denaturing as well. Seemingly, at temperatures where protein self-dynamics allows large-scale H/D exchange, lipid-protein coupling is so weak that proteins prefer aggregating to limit the exposure of their hydrophobic surface regions to water. In all membranes studied, dynamics seemed to be governed by lipids around the low-temperature limit, and by proteins around the high-temperature limit of membrane functionality.PACS codes: 87.14.ep,, 87.16.D. PMID:19351429

Szalontai, Balázs



Lipid-lowering agents and hepatotoxicity.  


Lipid-lowering therapy is increasingly being used in patients for a variety of diseases, the most important being secondary prevention of cardiovascular disease. Many lipid-lowering drugs carry side effects that include elevations in hepatic function tests and liver toxicity. In many cases, these drugs are not prescribed or they are underprescribed because of fears of injury to the liver. This article attempts to review key trials with respect to the hepatotoxicity of these drugs. Recommendations are also provided with respect to the selection of low-risk patients and strategies to lower the risk of hepatotoxicity when prescribing these medications. PMID:24099026

Demyen, Michael; Alkhalloufi, Kawtar; Pyrsopoulos, Nikolaos T



Alternative lipid mobilization: the insect shuttle system.  


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

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



Self-assembly between biomacromolecules and lipids  

NASA Astrophysics Data System (ADS)

Anionic DNA and cationic lipsomes can self-assemble into a multi-lamellar structure where two-dimensional (2-D) lipid sheets confine a periodic one-dimensional (1-D) lattice of parallel DNA chains, between which Cd2+ ions can condense, and be subsequently reacted with H 2S to template CdS nanorods with crystallographic control analogous to biomineralization. The strong electrostatic interactions align the templated CdS (002) polar planes parallel to the negatively charged sugar-phosphate DNA backbone, which indicates that molecular details of the DNA molecule are imprinted onto the inorganic crystal structure. The resultant nanorods have (002) planes tilted by ˜60° with respect to the rod axis, in contrast to all known II-VI semiconductor nanorods. Rational design of the biopolymer-membrane templates is possible, as demonstrated by the self-assembly between anionic M13 virus and cationic membrane. The filamentous virus has diameter ˜3x larger but similar surface charge density as DNA, the self-assembled complexes maintain the multi-lamellar structure, but pore sizes are ˜10x larger in area, which can be used to package and organize large functional molecules. Not only the counter-charged objects can self-assemble, the like-charged biopolymer and membrane can also self-assemble with the help of multivalent ions. We have investigated anionic lipid-DNA complexes induced by a range of divalent ions to show how different ion-mediated interactions are expressed in the self-assembled structures, which include two distinct lamellar phases and an inverted hexagonal phase. DNA can be selectively organized into or expelled out of the lamellar phases depending on membrane charge density and counterion concentration. For a subset of ion (Zn2+ etc.) at high enough concentration, 2-D inverted hexagonal phase can be formed where DNA strands are coated with anionic lipid tubes via interaction with Zn2+ ions. We suggest that the effect of ion binding on lipid's spontaneous curvature is sufficient to explain the lamellar to inverted hexagonal transition. Finally, we studied the interaction of anionic DNA with zwitterionic lipids at the presence of multivalent ions. Polymorphism of phases was found depending on lipid's intrinsic curvature. The anionic lipid-DNA and zwitterionic lipid-DNA complexes are currently emerged as new types of gene delivery systems with low cytotoxicity.

Liang, Hongjun


Signalling steps in apoptosis by ether lipids  

Microsoft Academic Search

We have investigated the mechanisms of induction of apoptosis by the antineoplastic ether lipid ET-18-OCH3 (ALP) in sensitive S49wt mouse lymphoma cells and ALP-resistant S49ar variants, both with wild-type p53, and in related L1210 cells with mutated p53. Ether lipid-resistant S49ar cells were cross-resistant to extracellular stress factors (cold shock, heat shock, H2O2, dimethylsulfoxide) and to radiation-induced apoptosis but not

L. A. Smets; H. Van Rooij; G. S. Salomons



Aluminum stress response in rice: effects on membrane lipid composition and expression of lipid biosynthesis genes.  


The presence of aluminum (Al) in acidic soils is a major abiotic stress limiting the production of cultivated plants. Cell membranes are the main targets of environmental stresses and there is growing evidence for the involvement of membrane lipids in plant adaptation. The aim of this study was to evaluate the mid-long effects of Al on membrane lipid content and composition in the roots and shoots of rice plants grown under hydroponic conditions. Four rice cultivars were compared: two acknowledged as Al-resistant (Koshihikari) and Al-sensitive (Kasalath), respectively, and two Vietnamese cultivars, OM6073 and OM1490. Al treatment inhibited root and shoot growth in the sensitive cultivars and the observed changes in root and shoot lipid and fatty acid composition revealed patterns associated with Al sensitivity: larger decreases in lipid content and decreases in fatty acid unsaturation. In the roots, phospholipids, and particularly phosphatidylcholine (PC), decreased dramatically in the susceptible cultivars whereas the amount of lipid classes remained unchanged in the tolerant ones. In the shoots, the glycolipids monogalactosyldiacylglycerol and digalactosyldiacylglycerol as well as PC were mostly affected by Al treatment in the susceptible varieties. mRNA accumulation corresponding to genes coding for galactolipid synthases, enzymes of the PC and phosphatidylethanolamine biosynthetic pathways and fatty acid desaturases correlated well with changes in lipid contents in roots and partly explained lipid changes in leaves. The results suggested that the capacity to maintain the proper functioning of some lipid biosynthetic activities and hence the stability of lipid composition may help the rice plant to withstand Al stress. PMID:22452575

Huynh, Van-Biet; Repellin, Anne; Zuily-Fodil, Yasmine; Pham-Thi, Anh-Thu



Investigating lipid-lipid and lipid-protein interactions in model membranes by ToF-SIMS  

PubMed Central

With the chemical imaging capability of ToF-SIMS, biological molecules are identified and localized in membranes without any chemical labels. We have developed a model membrane system made with supported Langmuir–Blodgett (LB) monolayers. This simplified model can be used with different combinations of molecules to form a membrane, and thus represents a bottom-up approach to study individual lipid–lipid or lipid–protein interactions. We have used ternary mixtures of sphingomyelin (SM), phosphatidylcholine (PC), and cholesterol (CH) in the model membrane to study the mechanism of domain formation and interactions between phospholipids and cholesterol. Domain structures are observed only when the acyl chain saturation is different for SM and PC in the mixture. The saturated lipid, whether it is SM or PC, is found to be localized with cholesterol, while the unsaturated one is excluded from the domain area. More complicated model membranes which involve a functional membrane protein glycophorin are also investigated and different membrane properties are observed compared to the systems without glycophorin.

Zheng, L.; McQuaw, C.M.; Baker, M.J.; Lockyer, N.P.; Vickerman, J.C.; Ewing, A.G.; Winograd, N.



A compositional based model for the tear film lipid layer.  

PubMed Central

BACKGROUND: The tear film lipid layer is formed from lipids secreted by meibomian glands of the eyelid. After initial analyses of these lipids we concluded that an understanding of the function of the various classes of lipids in a normal lipid layer could only be understood after detailed investigations of both polar and nonpolar lipids of the meibomian gland. METHODS: Meibomian gland secretions were obtained from normals. Lipids were separated by thin layer chromatography and high pressure liquid chromatography, and analyzed by UV absorbance, gas chromatography and mass spectroscopy. RESULTS: Based on our analyses we concluded that the current understanding of lipid layer composition and function were inadequate or misleading. We therefore propose that the more polar lipids function as a structure (with surfactant characteristics) upon which the functional stability of the more nonpolar lipids are dependent. We further suggest that the interrelationships between lipid classes present, length of fatty acids and alcohols, their unsaturation, and hydroxylation are important for maintaining proper thixotropic characteristics of the lipid layer as well as optimal barrier properties. CONCLUSION: The tear film lipid layer is composed of 2 phases: (1) a thin polar phase adjacent to the aqueous-mucin phase and (2) a thick nonpolar phase associated with both the polar phase and the air interface. The structural characteristics of the polar phase and the barrier functions of the nonpolar phase are a direct result of specific compositional parameters.

McCulley, J P; Shine, W



Long and short lipid molecules experience the same interleaflet drag in lipid bilayers.  


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?3×10(9)??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

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



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

NASA Astrophysics Data System (ADS)

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.

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



Effect of different lipids and surfactants on formulation of solid lipid nanoparticles incorporating tamoxifen citrate  

PubMed Central

Tamoxifen Citrate (TC) is an estrogen receptor antagonist and drug of choice for hormone sensitive breast cancer. Solid Lipid Nanoparticles loaded with TC were prepared by High Shear Homogenization followed by Ultrasonication. The aim of the present work is to study the effect of four different Solid Lipids and three Surfactants on Formulation and Stability of SLN. They were characterized for Particle size, Polydispersity Index and Zeta Potential by Zetasizer Nano. SLN prepared by Solid Lipid Compritol 888 (Glyceryldibehenate) and Tween 80 (1%) showed desired Particle Size of 206.9 nm, PDI of 0.046 and Zeta Potential of 9.32 mV.

Upadhyay, S. U.; Patel, J. K.; Patel, V. A.; Saluja, A. K.



Investigation of Phase and State Relations in Complex Lipid Systems.  

National Technical Information Service (NTIS)

The project was designed to examine the ion and water permeability of lipid phases in various lipid-polymer-water mixtures; the effect that changes in phase structure might have upon that permeability; and whether the permeability relations so elaborated ...

R. C. Bean



Lipid Composition of Marine and Estuarine Invertebrates: Porifera and Cnidaria.  

National Technical Information Service (NTIS)

It is evident, although based upon somewhat limited data, that the Porifera and the Cnidaria differ substantially in their lipid composition and metabolism. Only one class of sponges, the Demospongiae, has been studied, but the lipids of these sponges are...

J. D. Joseph



Preservation Potential of Lipid-Containing Viruses Under Silicifying Conditions  

NASA Astrophysics Data System (ADS)

The preservation potential of lipid-containing viruses, PRD1 and PBCV1, within silicifying solutions exists. Both viruses are rapidly removed from precipitating solutions, and the lipids within PBCV1 are unique from that of their host.

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



Near infrared Raman spectra of human brain lipids  

NASA Astrophysics Data System (ADS)

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.

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



Unique Lipid Deposits in Porpoise Head Tissues Associated with Biosonar.  

National Technical Information Service (NTIS)

A review of work on lipid structures of porpoise head tissues associated with sound transmission is presented. Studies revealed that the melon and mandibular canal of Tursiops gilli contain primarily two lipid classes, triacylglycerols and wax esters. The...

D. C. Malins U. Varanasi



21 CFR 862.1470 - Lipid (total) test system.  

Code of Federal Regulations, 2013 CFR

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



Lipid Raft: A Floating Island Of Death or Survival  

PubMed Central

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

George, Kimberly S.; Wu, Shiyong




Microsoft Academic Search

This review presents recent extensive developments of HPLC for evaluation of lipid structures. Some parameters for optimizing chromatographic methodology for the lipid analysis are discussed in detail. Finally future implications of HPLC is critically reviewed.

Vijai K. S. Shukla



Phosphate-limitation mediated lipid production by Rhodosporidium toruloides.  


Nitrogen-limited conditions have been routinely prepared for efficient lipid production by oleaginous microorganisms. However, it is difficult to attain high cellular lipid contents with natural nitrogen-rich substrates. In the present study, we showed that lipid accumulation by Rhodosporidium toruloides Y4 was directly linked to the carbon to phosphorus (C/P) molar ratios of the culture media. Moreover, such lipid accumulation phenomena were effective regardless of the presence of high amounts of nitrogen sources. Thus, cellular lipid content and lipid yield were 62.2% and 0.205 g/g glucose, respectively, using a medium with a carbon to nitrogen (C/N) molar ratio of 6.1 and a C/P molar ratio of 9552. This work suggested that phosphorus limitation can be equally effective and efficient to mediate lipid accumulation, which in turn, provides opportunities to produce microbial lipid more economically using natural or waste materials with high nitrogen content. PMID:20307977

Wu, Siguo; Hu, Cuimin; Jin, Guojie; Zhao, Xin; Zhao, Zongbao K



An Introduction to Lipid Analysis in the Cell Biology Laboratory.  

ERIC Educational Resources Information Center

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

Schuh, Timothy J.



Injected Omental Lipids for Treatment of Soft Tissue Injury.  

National Technical Information Service (NTIS)

Omental lipids have been shown to be potent angiogenic compounds. In several models, these lipids have improved healing. This investigation was to determine if a single injected dose could improve militarily relevant injuries frostbite and soft tissue inj...

A. Hall C. Woodham



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...


Lipid encapsulated docosahexaenoic acid methyl ester  

Technology Transfer Automated Retrieval System (TEKTRAN)

Encapsulation of structurally sensitive compounds within a solid lipid matrix provides a barrier to prooxidant compounds and effectively limits the extent of oxidative degradation. Encapsulated docosahexaenoic acid (DHA) methyl ester was examined as a model compound for functional foods and feeds. S...


Lipid Transfer Proteins and Allergy to Oranges  

Microsoft Academic Search

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

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



1999 Gordon Research Conference on Lipid Metabolism.  

National Technical Information Service (NTIS)

The 1999 Gordon Research Conference on Molecular and Cellular Biology of Lipids was held June 27 - July 2 at Kimball Union Academy in Meriden, NH. The attendees represented a broad group of participants. Each session brought out new and important informat...

W. Dowhan



Lipid and Fatty Acid Requirements of Tilapia  

Technology Transfer Automated Retrieval System (TEKTRAN)

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


Bilateral Progressive Idiopathic Annular Lipid Keratopathy  

PubMed Central

Purpose. To report two unusual cases of idiopathic lipid keratopathy with symmetrical bilateral annular corneal lipid infiltration and describe confocal microscopy findings. Methods. Case reports. Results. We report two patients with bilateral peripheral deep stromal lipid deposits beginning in an arcuate pattern and progressing to a complete annular shape. Cholesterol crystals were observed in the paracentral area in both cases with characteristic crystalline-like structures in the confocal microscopy. Deep thin corneal blood vessels were observed in one patient, but no cause for then was established, despite decades of followup. This patient had an idiopathic limbitis as well, occurring in episodes. No previous ocular trauma, systemic disease or family history was reported for both cases. Conclusion. These two cases of idiopathic annular lipid keratopathy were observed for more than a decade with documented slow and insidious progression of the infiltrates, in spite of the use of topical steroids in one case. In the majority of other reported cases, a penetrating keratoplasty was made necessary. Differently, we showed that the visual acuity can remain quite good for years with very slow deterioration.

Ghanem, Ramon C.; Ghanem, Vinicius C.; Victor, Gustavo; Alves, Milton Ruiz



Lean Pork for Lipid-lowering Diets  

Microsoft Academic Search

The conventional recommendation that lipid-lowering diets contain reduced amounts of red meats limits an important dietary source of nutrients. In an effort to address this problem, we analyzed 10 cuts from the loin and shoulder of a newly developed leaner pork (LP) product (5 boneless, 5 bone-in, n= 12 ea) for total fat, fatty acids, and cholesterol using standard AOAC

C. Bales; K. Moreno; S. Brown; J. Guyton; M. McGee; K. Currie; M. Drezner



Altered lipid content inhibits autophagic vesicular fusion.  


The autophagic/lysosomal system includes a variety of vesicular compartments that undergo dynamic fusion events. However, the characteristics and factors modulating these interactions remain, for the most part, unknown. To gain insights on the properties that govern lysosomal fusion events, we have established an in vitro fusion assay using different lysosomal/autophagic compartments isolated from mouse liver. We have found that autophagosome/lysosome fusion is a temperature-dependent process (fusion increment of 0.2+/-0.01%/degrees C), which requires ATP (1-3 mM), GTP (1-2 mM), Ca(2+) (0.2-2 mM), and an acidic lysosomal pH (pH 5.2). Furthermore, changes in membrane lipid composition, induced either in vitro, by treatment with 25 mM methyl-beta-cyclodextrin, or in vivo, by subjecting animals to a high-fat-diet challenge (60% kcal in fat) reduce autophagosome/lysosome fusion up to 70% of that observed in untreated fractions or from animals under a normal regular diet. These findings reveal a novel role for lipids in autophagic fusion and provide a mechanism for the reduced macroautophagic rates observed during exposure to a chronic lipid challenge. Changes in the intracellular lipid content (i.e., metabolic disorders) may thus have pronounced effects on the fusion step of macroautophagy and affect the overall activity of this intracellular proteolytic pathway. PMID:20375270

Koga, Hiroshi; Kaushik, Susmita; Cuervo, Ana Maria



Organization in Lipid Membranes Containing Cholesterol  

Microsoft Academic Search

A fundamental attribute of raft formation in cell membranes is lateral separation of lipids into coexisting liquid phases. Using fluorescence microscopy, we observe spontaneous lateral separation in free-floating giant unilamellar vesicles. We record coexisting liquid domains over a range of composition and temperature significantly wider than previously reported. Furthermore, we establish correlations between miscibility in bilayers and in monolayers. For

Sarah L. Veatch; Sarah L. Keller



Lipid rafts: bringing order to chaos  

Microsoft Academic Search

Lipid rafts are subdomains of the plasma mem- brane that contain high concentrations of cholesterol and glycosphingolipids. They exist as distinct liquid-ordered re- gions of the membrane that are resistant to extraction with nonionic detergents. Rafts appear to be small in size, but may constitute a relatively large fraction of the plasma membrane. While rafts have a distinctive protein and

Linda J. Pike



Lipid abnormalities in uremia, dialysis, and transplantation  

Microsoft Academic Search

The institution of renal replacement therapy has sustained the lives of many patients with end-stage renal failure and has made it possible to study in depth the metabolic abnormalities associated with the uremic state. An important consequence of chronic uremia is the development of lipid abnormalities [1, 2], which continue to affect many patients on dialysis [1, 3, 4] and

Man Kam Chan; Zachariah Varghese; John F Moorhead



Lipid Bilayers and Titanium: Controlling Surface Adsorption  

NASA Astrophysics Data System (ADS)

Used extensively for implants, titanium is relatively inert in the body, and considered a biocompatible metal. We have investigated the interactions of cationic lipid mixtures with a highly polished bulk TiO2 surface and report the observation of an interesting cationic lipid tubule phase stabilized in 2D on the TiO2 surface. This phase is distinct from the bulk tubule phase observed in some mixtures as the tubules form a network with small mesh size and appear to be more flexible. Cationic lipid vesicles were formed under various salt conditions and deposited on the TiO2 surface via vesicle absorption, then observed with fluorescence microscopy. In certain mixtures, bulk tubule phases were observed. When deposited on glass the bulk tubule phase became unstable and bilayers gradually formed on the glass surface. However, deposition of the same cationic mixtures on TiO2 resulted in the formation of a 2D network of lipid tubules on the surface. The network, although pinned to the surface remained fluid in nature, as confirmed by FRAP experiments. The tubules appear to be only weakly attracted to the TiO2 and this may explain their stability on the surface.

Hirst, Linda S.; Parker, Emily; MacDonald, Noel C.; Safinya, Cyrus R.



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...


Lipid Injectable Emulsions: Pharmacopeial and Safety Issues  

Microsoft Academic Search

Abstract  Lipid injectable emulsions have been routinely used in patients worldwide for over 40 years as a nutritional supplement in patients requiring parenteral nutrition. They can be given as a separate infusion or added into total parenteral nutrition admixtures. Despite such broad use, no pharmacopeial standards exist with respect to the optimal pharmaceutical characteristics of the formulation. Several attempts to establish

David F. Driscoll



TOPICAL REVIEW: The microcalorimetry of lipid membranes  

NASA Astrophysics Data System (ADS)

Insight into the forces governing a system is essential for understanding its behaviour and function. Calorimetric investigations provide a wealth of information that is not, or is hardly, available by other methods. This paper reviews calorimetric approaches and assays for the study of lipid vesicles (liposomes) and biological membranes. With respect to the instrumentation, differential scanning calorimetry (DSC), pressure perturbation calorimetry (PPC), isothermal titration calorimetry (ITC) and water sorption calorimetry are considered. Applications of these techniques to lipid systems include the measurement of thermodynamic parameters and a detailed characterization of the thermotropic, barotropic, and lyotropic phase behaviour. The membrane binding or partitioning of solutes (proteins, peptides, drugs, surfactants, ions, etc) can also be quantified. Many calorimetric assays are available for studying the effect of proteins and other additives on membranes, characterizing non-ideal mixing, domain formation, stability, curvature strain, permeability, solubilization, and fusion. Studies of membrane proteins in lipid environments elucidate lipid-protein interactions in membranes. The systems are described in terms of enthalpic and entropic forces, equilibrium constants, heat capacities, partial volume changes etc, shedding light also on the stability of structures and the molecular origin and mechanism of structural changes.

Heerklotz, Heiko



Lesions due to Complement in Lipid Membranes  

Microsoft Academic Search

WHEN cells are lysed by antibody and complement (C), uniform bubbles or ``holes'' revealed by negative staining in the electron microscope appear at the surface. These lesions are probably due to micelle formation in the surface lipid layer (evidence reviewed in ref. 1). C activated by antibody through C8 has also been shown to damage liposomes containing Forssman antigen in

T. R. Hesketh; R. R. Dourmashkin; Sheila N. Payne; J. H. Humphrey; P. J. Lachmann



Lipid chemistry of eastern Mediterranean surface layers  

Microsoft Academic Search

IT has been well established that organic surface films exist in most of the world's major oceans1-9. They consist mainly of natural lipid material, with generally much smaller, though variable, amounts of petroleum hydrocarbons. Because the Mediterranean Sea is a restricted area the input of petroleum hydrocarbon is more noticeable than in most oceanic areas, and the level of surface

R. J. Morris; F. Culkin



Serum lipids and cardiovascular reactivity to stress  

Microsoft Academic Search

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

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



Decomposition of food lipids by ionizing radiation  

Microsoft Academic Search

A number of animal and vegetable fats as well as model systems of ; triglycerides were used in a study to examine the effects of irradiation on the ; lipid fraction of foods. More than one hundred compounds were identified as ; radiolytic products. These include a series of hydrocarbons, aldehydes, esters, ; free acids, ethane- and propanediol diesters, propenediol




Lipid composition of myelin in multiple sclerosis  

Microsoft Academic Search

Myelin was isolated from histologically normal white matter and plaques from MS patients and from white matter of neurologically normal controls. No difference was found in the total lipid content. There were no detectable deficits in MS myelin of phosphoglycerides, plasmalogens or sphingolipids. Gangliosides and lysolecithin were not detected. Analysis of the fatty aldehyde composition of the phosphoglycerides and the

Mona E. Fewster; H. Hirono; J. F. Mead



Waxes: A Forgotten Topic in Lipid Teaching.  

ERIC Educational Resources Information Center

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

Dominguez, Eva; Heredia, Antonio




Technology Transfer Automated Retrieval System (TEKTRAN)

Cardiovascular diseases (CVD) result from complex interactions between genetic and environmental factors. The evidence supports that gene-environment interactions modulate plasma lipid concentrations and potentially CVD risk. Several genes [i.e., APOA1, APOA4, APOE, and LIPC] are providing proof-of-...


Synthesis and Characterization of Betaine-like Diacyl Lipids: Zwitterionic Lipids with the Cationic Group at the Bilayer Interface  

PubMed Central

We synthesized and characterized a series of zwitterionic, acetate-terminated, quaternized amine diacyl lipids (AQ). These lipids have an inverted headgroup orientation as compared to naturally occurring phosphatidylcholine (PC) lipids; the cationic group is anchored at the membrane interface, while the anionic group extends into the aqueous phase. AQ lipids preferentially interact with highly polarizable anions (ClO4?) over less polarizable ions (Cl?), in accord with the Hofmeister series, as measured by the change in zeta potential of AQ liposomes. Conversely, AQ lipids have a weaker association with calcium than do PC lipids. The transition temperatures (Tm) of the AQ lipids are similar to the Tm observed with phosphatidylethanolamine (PE) lipids of the same chain length. AQ lipids form large lipid sheets after heating and sonication; however, in the presence of cholesterol, (Chol) these lipids form stable liposomes that encapsulate carboxyfluorescein. The AQ:Chol liposomes retain their contents in the presence of serum at 37 °C, and when injected intravenously into mice, their organ biodistribution is similar to that observed with PC:Chol liposomes. AQ lipids demonstrate that modulating the headgroup charge orientation significantly alters the biophysical properties of liposomes. For the drug carrier field, these new materials provide a non-phosphate containing zwitterlipid for the production of lipid vesicles.

Kohli, Aditya G.; Walsh, Colin L.; Szoka, Francis C.



Lipid-Protein Interaction During Aqueous Extraction of Fish Protein: Actin-Lipid Interaction.  

National Technical Information Service (NTIS)

The paper presents the results of actin-lipid interaction in aqueous medium, studied by sucrose gradient centrifugation and polyacrylamide gel electrophoresis techniques. Results of the effect of transforming G-actin into F-actin, effect of room temperatu...

S. Y. K. Shenouda G. M. Pigott



Exploring lipid\\/peptide and lipid\\/protein interactions using fluorescence microscopy  

Microsoft Academic Search

Compared with traditional fluorescence studies involving lipid vesicles, the use of giant unilamellar vesicles (GUVs) under confocal\\/two-photon excitation fluorescence microscopy offers a variety of unique advantages. The combination of these \\



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

PubMed Central

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.

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



Atomistic Study of Lipid Membranes Containing Chloroform: Looking for a Lipid-Mediated Mechanism of Anesthesia  

PubMed Central

The molecular mechanism of general anesthesia is still a controversial issue. Direct effect by linking of anesthetics to proteins and indirect action on the lipid membrane properties are the two hypotheses in conflict. Atomistic simulations of different lipid membranes subjected to the effect of small volatile organohalogen compounds are used to explore plausible lipid-mediated mechanisms. Simulations of homogeneous membranes reveal that electrostatic potential and lateral pressure transversal profiles are affected differently by chloroform (anesthetic) and carbon tetrachloride (non-anesthetic). Simulations of structured membranes that combine ordered and disordered regions show that chloroform molecules accumulate preferentially in highly disordered lipid domains, suggesting that the combination of both lateral and transversal partitioning of chloroform in the cell membrane could be responsible of its anesthetic action.

Reigada, Ramon



Lipid-based Nanoparticles for Nucleic Acid Delivery  

Microsoft Academic Search

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

Weijun Li; Francis C. Szoka Jr



Lipid A Binding to Neonatal and Adult Red Blood Cells  

Microsoft Academic Search

Lipid A is responsible for the endotoxic activities of gram-negative bacteria. Binding of lipid A (50 ?g\\/ml) to RBC was studied using a passive hemolysis test. RBC from adults, cord and venous RBC from full-term infants and RBC from preterm infants were studied. Lipid A sensitized RBC were hemolysed with anti-lipid A and guinea pig complement. Hemolysis was expressed as

J. M. B. Pöschl; M. Schnauffer; C. Galanos; O. Linderkamp



Halothane changes the domain structure of a binary lipid membrane.  


X-ray and neutron diffraction studies of a binary lipid membrane demonstrate that halothane at physiological concentrations produces a pronounced redistribution of lipids between domains of different lipid types identified by different lamellar d-spacings and isotope composition. In contrast, dichlorohexafluorocyclobutane (F6), a halogenated nonanesthetic, does not produce such significant effects. These findings demonstrate a specific effect of inhalational anesthetics on mixing phase equilibria of a lipid mixture. PMID:22352350

Weinrich, Michael; Nanda, Hirsh; Worcester, David L; Majkrzak, Charles F; Maranville, Brian B; Bezrukov, Sergey M



Lipid–protein interactions in biological membranes: a structural perspective  

Microsoft Academic Search

Lipid molecules bound to membrane proteins are resolved in some high-resolution structures of membrane proteins. An analysis of these structures provides a framework within which to analyse the nature of lipid–protein interactions within membranes. Membrane proteins are surrounded by a shell or annulus of lipid molecules, equivalent to the solvent layer surrounding a water-soluble protein. The lipid bilayer extends right

A. G. Lee



Role of cholesterol and lipid organization in disease  

NASA Astrophysics Data System (ADS)

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 Tangier disease, Niemann-Pick disease type C and atherosclerosis. These insights have also led to improved understanding of normal physiology.

Maxfield, Frederick R.; Tabas, Ira



Excretion of lipids by the liver fluke ( Fasciola Hepatica L)  

Microsoft Academic Search

Adult liver flukes kept in a glucoseenriched medium were found to excrete lipids. Analysis of the incubation medium showed\\u000a that both neutral lipids (including cholesterol and its esters) and polar lipids were released. The rate of lipid excretion\\u000a was greatly reduced when the excretory pores and mouths of the flukes were ligated. Histochemical examination of the flukes\\u000a indicated that such

C. H. Burren; I. Ehrlich; P. Johnson



Observations on the lipids of Oochoristica agamae (Cestoda)  

Microsoft Academic Search

An investigation of the lipids ofOochoristica agamae, an anoplocephalid cestode of theAgama lizard, was undertaken. Total lipids of the parasite accounted for 8.4% of the fresh weight; neutral lipids comprised 82.98% of the total, glycolipids, 5.01%, and phospholipids, 12.03%. The major lipid classes inO. agamae include triglycerides, cholesterol, phosphatidyl choline, and phosphatidyl ethanolamine. The 16-and 18-carbon fatty acids were predominant

Siaka O. Aisien; Edward E. Ogiji



Lipid extrudates as novel sustained release systems for pharmaceutical proteins  

Microsoft Academic Search

In order to develop improved lipid-based implants for proteins, the applicability of twin screw extrusion as a manufacturing strategy was investigated. Using lipid blends of low and high melting lipids, extrusion could be performed at moderate temperatures. In addition to the lipids, the implant systems contained 10% rh-interferon ?-2a (IFN-?) co-lyophilised with hydroxypropyl-?-cyclodextrin (HP-?-CD), and 10% or 20% polyethylene glycol

Sandra Schulze; Gerhard Winter



MR-Visible Lipids and the Tumor Microenvironment  

PubMed Central

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.

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



Phosphate-limitation mediated lipid production by Rhodosporidium toruloides  

Microsoft Academic Search

Nitrogen-limited conditions have been routinely prepared for efficient lipid production by oleaginous microorganisms. However, it is difficult to attain high cellular lipid contents with natural nitrogen-rich substrates. In the present study, we showed that lipid accumulation by Rhodosporidium toruloides Y4 was directly linked to the carbon to phosphorus (C\\/P) molar ratios of the culture media. Moreover, such lipid accumulation phenomena

Siguo Wu; Cuimin Hu; Guojie Jin; Xin Zhao; Zongbao K. Zhao



CELL BIOLOGY: The Different Hues of Lipid Rafts  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Segregation of lipids and proteins of the plasma membrane into microdomains called lipid rafts is known to be important for many biological processes including signal transduction and pathogen invasion. In his Perspective, van Meer explains new findings (Zacharias et al.) that reveal how lipid moieties attached to proteins instruct the proteins to move into different types of lipid rafts.

Gerrit van Meer (Utrecht University;Department of Membrane Enzymology, CBLE, Institute of Biomembranes)



Molecular driving forces defining lipid positions around aquaporin-0  

PubMed Central

Lipid–protein interactions play pivotal roles in biological membranes. Electron crystallographic studies of the lens-specific water channel aquaporin-0 (AQP0) revealed atomistic views of such interactions, by providing high-resolution structures of annular lipids surrounding AQP0. It remained unclear, however, whether these lipid structures are representative of the positions of unconstrained lipids surrounding an individual protein, and what molecular determinants define the lipid positions around AQP0. We addressed these questions by using molecular dynamics simulations and crystallographic refinement, and calculated time-averaged densities of dimyristoyl-phosphatidylcholine lipids around AQP0. Our simulations demonstrate that, although the experimentally determined crystallographic lipid positions are constrained by the crystal packing, they appropriately describe the behavior of unconstrained lipids around an individual AQP0 tetramer, and thus likely represent physiologically relevant lipid positions.While the acyl chains were well localized, the lipid head groups were not. Furthermore, in silico mutations showed that electrostatic interactions do not play a major role attracting these phospholipids towards AQP0. Instead, the mobility of the protein crucially modulates the lipid localization and explains the difference in lipid density between extracellular and cytoplasmic leaflets. Moreover, our simulations support a general mechanism in which membrane proteins laterally diffuse accompanied by several layers of localized lipids, with the positions of the annular lipids being influenced the most by the protein surface. We conclude that the acyl chains rather than the head groups define the positions of dimyristoyl-phosphatidylcholine lipids around AQP0. Lipid localization is largely determined by the mobility of the protein surface, whereas hydrogen bonds play an important but secondary role.

Aponte-Santamaria, Camilo; Briones, Rodolfo; Schenk, Andreas D.; Walz, Thomas; de Groot, Bert L.



Linoleic acid stimulates neutral lipid accumulation in lipid droplets of maturing bovine oocytes.  


Linoleic acid (LA) is a polyunsaturated fatty acid present in high concentrations in bovine follicular fluid; when added to maturation culture media, it affects oocyte competence (depending on the type and concentration of LA used). To date, little is known about the effective level of incorporation of LA and there is apparently no information regarding its esterification into various lipid fractions of the oocyte and its effect on neutral lipid storage. Therefore, the objective was to assess the uptake and subcellular lipid distribution of LA by analyzing incorporation of radiolabeled LA into oocyte polar and neutral lipid classes. The effects of various concentrations of LA on the nuclear status and cytoplasmic lipid content of bovine oocytes matured in vitro was also analyzed, with particular emphasis on intermediate concentrations of LA. Neutral lipids stored in lipid droplets were quantified with a fluorescence approach. Linoleic acid at 9 and 43 ?M did not affect the nuclear status of oocytes matured in vitro, and 100 ?M LA inhibited germinal vesicle breakdown, resulting in a higher percentage of oocytes arrested at the germinal state (43.5 vs. 3.0 in controls; P < 0.05). Bovine oocytes actively incorporated LA from the maturation medium (83.4 pmol LA per 100 oocytes at 22 hours of incubation; P < 0.05) and metabolized it mainly into major lipid classes, e.g., triacylglycerols and phospholipids (61.1% and 29.3%, respectively). Supplementation of the maturation medium with LA increased triacylglycerol accumulation in cytoplasmic lipid droplets at all concentrations assayed (P < 0.05). In conclusion, LA added to a defined maturation medium at concentrations that did not alter the nuclear status of bovine oocytes matured in vitro (9 and 43 ?M) improved their quality by increasing the content of neutral lipids stored in lipid droplets. By directing the free fatty acid (LA) to triacylglycerol synthesis pathways and increasing the degree of unsaturation of membrane phospholipids, the oocyte was protected from lipotoxic effects (with an expectation of improved cryotolerance). PMID:23273433

Carro, M; Buschiazzo, J; Ríos, G L; Oresti, G M; Alberio, R H



Lipid profile of regular blood donors  

PubMed Central

Introduction A few reports have linked regular blood donation to the lowering of parameters of lipid profile. Estimating the lipid profile is an accepted method of assessing an individual’s risk for coronary heart disease, particularly if there is evidence of lipid peroxidation. Regular blood donation may lower iron stores, and this in turn lowers lipid peroxidation. This study was carried out to determine the effect of blood donation on lipid profile. Materials and methods Eighty-two participants consented to participate and were enrolled into the study, 52 of whom were regular blood donors (study group) and 30 were non-donors (control group). Venous blood (10 mL) was drawn from each subject into new plain screw-capped disposable plastic tubes. This was allowed to clot and the serum was used to determine total cholesterol, triglycerides, low-density lipoprotein, and high-density lipoprotein. Results The mean total cholesterol (4.66 ± 0.86 mmol/L), triglycerides (1.22 ± 0.64 mmol/L), and low-density lipoprotein (2.32 ± 0.73 mmol/L) were significantly lower in the regular blood donors than the control group (5.61 ± 1.26 mmol/L, 1.77 ± 2.9 mmol/L, and 3.06 ± 0.89 mmol/L, respectively; P < 0.05 in all cases). Also, while 42% of the study group had a low/high-density lipoprotein ratio of at least three, about 57% of the control group had a ratio of at least three (P = 0.21). Conclusion Regular blood donation may be protective against cardiovascular disease as reflected by significantly lower mean total cholesterol and low-density lipoprotein levels in regular blood donors than in non-donors.

Uche, EI; Adediran, A; Damulak, OD; Adeyemo, TA; Akinbami, AA; Akanmu, AS



Cellular transport and lipid interactions of miltefosine.  


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

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



The effects of short term lipid infusion on plasma and hepatic bile lipids in humans  

PubMed Central

BACKGROUND—Patients on parenteral nutrition have an increased incidence of gall bladder sludge and gallstone disease, thought to be related to bile stasis. Intravenous lipid emulsions, especially those containing medium chain triglycerides, have also been shown to have a lithogenic effect on the composition of bile in the gall bladder.?AIMS—To determine whether lipid infusion influences hepatic bile composition in patients with an indwelling T tube following cholecystectomy and choledochotomy.?METHODS—In eight patients undergoing the above surgical procedure, the time at which effects of the interrupted enterohepatic circulation were minimal was determined. Twenty two cholesterol gallstone patients with bile fistula were then randomised to receive an infusion of a lipid emulsion containing either long chain triglycerides or a mixture of long and medium chain triglycerides.?RESULTS—Lipid infusion resulted in a significant increase in plasma levels of triglycerides and phospholipids. Both lipid emulsions caused an increase in hepatic biliary cholesterol level and cholesterol saturation index, but this effect was more pronounced with medium chain triglycerides. The fatty acid composition of biliary phospholipids showed a significant enrichment of linoleic acid by both lipid infusions.?CONCLUSIONS—Infusion of triglycerides causes lithogenic changes in hepatic bile composition in humans, the lithogenic effect of infusion of medium chain triglycerides being more pronounced than that of long chain triglycerides. This effect, coupled with gall bladder stasis, may be responsible for the increased risk of biliary sludge and gallstone formation in patients on long term lipid infusion.???Keywords: lipid emulsion; long chain triglycerides; medium chain triglycerides; bile; cholesterol; gallstones

Pakula, R; Konikoff, F; Moser, A; Greif, F; Tietz, A; Gilat, T; Rubin, M



Dietary Lipids Modify Intestinal Lipid-Binding Protein RNA Abundance in Diabetic and Control Rats  

Microsoft Academic Search

Background: Lipid-binding proteins have been identified in the enterocyte, including the cytosolic intestinal and liver fatty acid binding proteins (I-FABP and L-FABP, respectively) as well as the brush border membrane fatty acid transporter (FAT). It is unclear whether variations in the type of dietary lipids or diabetes modify the RNA abundance of these proteins. Diabetes is associated with an increased

L. Drozdowski; L. Clement; M. Keelan; I. Niot; M. T. Clandinin; L. Agellon; G. Wild; P. Besnard; A. B. R. Thomson



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

Microsoft Academic Search

The main function of cuticular lipids in insects is the restriction of water transpiration through the surface. Lipids are\\u000a involved in various types of chemical communication between species and reduce the penetration of insecticides, chemicals,\\u000a and toxins and they also provide protection from attack by microorganisms, parasitic insects, and predators. Hydrocarbons,\\u000a which include straight-chain saturated, unsaturated, and methyl-branched hydrocarbons, predominate

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



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


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

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



Quercetin induces hepatic lipid omega-oxidation and lowers serum lipid levels in mice.  


Elevated circulating lipid levels are known risk factors for cardiovascular diseases (CVD). In order to examine the effects of quercetin on lipid metabolism, mice received a mild-high-fat diet without (control) or with supplementation of 0.33% (w/w) quercetin for 12 weeks. Gas chromatography and (1)H nuclear magnetic resonance were used to quantitatively measure serum lipid profiles. Whole genome microarray analysis of liver tissue was used to identify possible mechanisms underlying altered circulating lipid levels. Body weight, energy intake and hepatic lipid accumulation did not differ significantly between the quercetin and the control group. In serum of quercetin-fed mice, triglycerides (TG) were decreased with 14% (p<0.001) and total poly unsaturated fatty acids (PUFA) were increased with 13% (p<0.01). Palmitic acid, oleic acid, and linoleic acid were all decreased by 9-15% (p<0.05) in quercetin-fed mice. Both palmitic acid and oleic acid can be oxidized by omega (?)-oxidation. Gene expression profiling showed that quercetin increased hepatic lipid metabolism, especially ?-oxidation. At the gene level, this was reflected by the up-regulation of cytochrome P450 (Cyp) 4a10, Cyp4a14, Cyp4a31 and Acyl-CoA thioesterase 3 (Acot3). Two relevant regulators, cytochrome P450 oxidoreductase (Por, rate limiting for cytochrome P450s) and the transcription factor constitutive androstane receptor (Car; official symbol Nr1i3) were also up-regulated in the quercetin-fed mice. We conclude that quercetin intake increased hepatic lipid ?-oxidation and lowered corresponding circulating lipid levels, which may contribute to potential beneficial effects on CVD. PMID:23359794

Hoek-van den Hil, Elise F; Keijer, Jaap; Bunschoten, Annelies; Vervoort, Jacques J M; Stankova, Barbora; Bekkenkamp, Melissa; Herreman, Laure; Venema, Dini; Hollman, Peter C H; Tvrzicka, Eva; Rietjens, Ivonne M C M; van Schothorst, Evert M



Quercetin Induces Hepatic Lipid Omega-Oxidation and Lowers Serum Lipid Levels in Mice  

PubMed Central

Elevated circulating lipid levels are known risk factors for cardiovascular diseases (CVD). In order to examine the effects of quercetin on lipid metabolism, mice received a mild-high-fat diet without (control) or with supplementation of 0.33% (w/w) quercetin for 12 weeks. Gas chromatography and 1H nuclear magnetic resonance were used to quantitatively measure serum lipid profiles. Whole genome microarray analysis of liver tissue was used to identify possible mechanisms underlying altered circulating lipid levels. Body weight, energy intake and hepatic lipid accumulation did not differ significantly between the quercetin and the control group. In serum of quercetin-fed mice, triglycerides (TG) were decreased with 14% (p<0.001) and total poly unsaturated fatty acids (PUFA) were increased with 13% (p<0.01). Palmitic acid, oleic acid, and linoleic acid were all decreased by 9–15% (p<0.05) in quercetin-fed mice. Both palmitic acid and oleic acid can be oxidized by omega (?)-oxidation. Gene expression profiling showed that quercetin increased hepatic lipid metabolism, especially ?-oxidation. At the gene level, this was reflected by the up-regulation of cytochrome P450 (Cyp) 4a10, Cyp4a14, Cyp4a31 and Acyl-CoA thioesterase 3 (Acot3). Two relevant regulators, cytochrome P450 oxidoreductase (Por, rate limiting for cytochrome P450s) and the transcription factor constitutive androstane receptor (Car; official symbol Nr1i3) were also up-regulated in the quercetin-fed mice. We conclude that quercetin intake increased hepatic lipid ?-oxidation and lowered corresponding circulating lipid levels, which may contribute to potential beneficial effects on CVD.

Hoek-van den Hil, Elise F.; Keijer, Jaap; Bunschoten, Annelies; Vervoort, Jacques J. M.; Stankova, Barbora; Bekkenkamp, Melissa; Herreman, Laure; Venema, Dini; Hollman, Peter C. H.; Tvrzicka, Eva; Rietjens, Ivonne M. C. M.; van Schothorst, Evert M.



Amylose-Lipid Complex Formation in Acetylated Pea Starch-Lipid Systems  

Microsoft Academic Search

Cereal Chem. 74(2):159-162 Starch-lipid interactions involving native and acetylated pea starch were studied by differential scanning calorimetry (DSC) and measure- ments of iodine affinity. Lipids including lauric acid, monopalm itin, and butterfat were added to aqueous starch dispersions after the starch was gelatinized at 85ºC. DSC thermal curves of gelatinized modified pea starch systems containing fatty acid or monoglyceride did

Hua Liu; Susan D. Arntfield; Richard A. Holley; David B. Aime



Role of lipid charge in organization of water/lipid bilayer interface: insights via computer simulations.  


Anionic unsaturated lipid bilayers represent suitable model systems that mimic real cell membranes: they are fluid and possess a negative surface charge. Understanding of detailed molecular organization of water-lipid interfaces in such systems may provide an important insight into the mechanisms of proteins' binding to membranes. Molecular dynamics (MD) of full-atom hydrated lipid bilayers is one of the most powerful tools to address this problem in silico. Unfortunately, wide application of computational methods for such systems is limited by serious technical problems. They are mainly related to correct treatment of long-range electrostatic effects. In this study a physically reliable model of an anionic unsaturated bilayer of 1,2-dioleoyl-sn-glycero-3-phosphoserine (DOPS) was elaborated and subjected to long-term MD simulations. Electrostatic interactions were treated with two different algorithms: spherical cutoff function and particle-mesh Ewald summation (PME). To understand the role of lipid charge in the system behavior, similar calculations were also carried out for zwitterionic bilayer composed of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). It was shown that, for the charged DOPS bilayer, the PME protocol performs much better than the cutoff scheme. In the last case a number of artifacts in the structural organization of the bilayer were observed. All of them were attributed to inadequate treatment of electrostatic interactions of lipid headgroups with counterions. Electrostatic properties, along with structural and dynamic parameters, of both lipid bilayers were investigated. Comparative analysis of the MD data reveals that the water-lipid interface of the DOPC bilayer is looser than that for DOPS. This makes possible deeper penetration of water molecules inside the zwitterionic (DOPC) bilayer, where they strongly interact with carbonyls of lipids. This can lead to thickening of the membrane interface in zwitterionic as compared to negatively charged bilayers. PMID:16852905

Polyansky, Anton A; Volynsky, Pavel E; Nolde, Dmitry E; Arseniev, Alexander S; Efremov, Roman G



Technology for Treatment of Lipid-Rich Wastewater and Pipelines Clogged by Lipids Using Bacterial Preparation  

Microsoft Academic Search

The complex, effective and innovative cleaning technology for lipid-rich wastewater and pipelines contaminated by lipids, was developed. For this purpose, laboratory experiments were performed to verify the efficiency of bacterial preparation (Enterobacter aerogenes E13, Arthrobacter sp. N3 and Bacillus coagulans S1) to degrade the grease in water and in drainpipes. The results showed that selected microorganisms intensively degrade grease to

Veslava Matikevi?ien?; Saulius Grigiškis; Donatas Levišauskas; Ona Kinderyt?; Egidijus Baškys



Lipid peroxidation of IV lipid emulsions in TPN bags: The influence of tocopherols  

Microsoft Academic Search

Four commercial IV lipid emulsions containing soybean oil were investigated to determine the tocopherol content. A sensitive high-performance liquid chromatography (HPLC) on a diol column was established to quantitate the tocopherol isomers in lipid emulsions. A previously described iodometric titration was used to assess the peroxide value (mmol peroxides\\/L). The pH was measured also. The initial tocopherol concentration ranges in

Patrick J. K. Steger; Stefan F. Mühlebach



Dependence of lipid membrane phase transition temperature on the mismatch of protein and lipid hydrophobic thickness  

Microsoft Academic Search

A two-component solution theory is studied which incorporates hydrophobic matching as a major contribution to the lipid-protein interactions in biological membranes. A special geometrical constraint has been discovered which has important implications for the quantitative interpretation of physical effects to lipid-protein interactions. The theory has an advantage over conventional Landau-type phenomenological descriptions in that it accounts for phase separation. A

M. M. Sperotto; O. G. Mouritsen



Permeability and electrical properties of planar lipid membranes from thylakoid lipids.  

PubMed Central

Electrical measurements were carried out on planar lipid membranes from thylakoid lipids. The specific capacitance of membranes formed from decane-containing monogalactosyldiacylglycerol (MGDG), which accounts for 57% of the total lipid content of thylakoids, showed that it adopted a bilayer structure. Solvent-free bilayers of MGDG were not formed, with very rare exceptions, indicating that decane is required to stabilize the planar conformation. However, this cone-shaped lipid produces bilayer structures in combination with other cylindrical thylakoid lipids even in the absence of organic solvent. We compared the properties of solvent-free and decane-containing bilayers from MGDG, soybean lecithin, and the quaternary mixture of lipids similar to that found in vivo. The conductance of decane-MGDG was 26 times higher than that of decane-lecithin. The flux through the decane-lecithin bilayer was found to be slightly dependent on pH, whereas the decane-MGDG membrane was not. The specific conductance of bilayers formed from the quaternary mixture of lipids was 5 to 10 times larger than lecithin (with alkane or not). Further experiments with bilayers made in the presence of a KCl gradient showed that decane-MGDG, decane-MGDG/DGDG/SQDG/PG, and solvent-free MGDG/DGDG/SQDG/PG were cation-selective. The permeability coefficient for potassium ranged from 4.9 to 8.3 x 10(-11) cm s-1. The permeability coefficient for protons in galactolipids, however, was determined to be about six orders of magnitude higher than the value for potassium ions. The HCl permeation mechanism through the lipid membranes was determined from diffusion potentials measured in HCl gradients. Our results suggest that HCl was not transported as neutral molecules. The data is discussed with regard to the function of galactolipids in the ion transport through thylakoid membranes.

Fuks, B; Homble, F



Rapid, colorimetric quantification of lipid from algal cultures  

Microsoft Academic Search

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

Boris Wawrik; Brian H. Harriman



Systems biology of lipid metabolism: From yeast to human  

Microsoft Academic Search

Lipid metabolism is highly relevant as it plays a central role in a number of human diseases. Due to the highly interactive structure of lipid metabolism and its regulation, it is necessary to apply a holistic approach, and systems biology is therefore well suited for integrated analysis of lipid metabolism. In this paper it is demonstrated that the yeast Saccharomyces

Jens Nielsen



Solid lipid extrusion of sustained release dosage forms  

Microsoft Academic Search

The applicability of the solid lipid extrusion process as preparations method for sustained release dosage forms was investigated in this study. Two lipids with similar melting ranges but of different composition, glyceryl palmitostearate (Precirol ATO 5®) and glyceryl trimyristate (Dynasan 114®), and mixtures of each lipid with 50% or 75% theophylline were extruded at temperatures below their melting ranges. Extrudates

Claudia Reitz; Peter Kleinebudde



In vitro assessment of oral lipid based formulations  

Microsoft Academic Search

In recent years there has been an increase in interest in the utility of lipid based delivery systems, at least in part as a result of the effective development of lipid based products such as Sandimmun Neoral® (cyclosporin), Norvir® (ritonavir) and Fortovase® (saquinavir). The development pathway for lipid based formulations, however, is still largely empirical, and in vitro models that

Christopher J. H Porter; William N Charman



LXR? Enhances Lipid Synthesis in SZ95 Sebocytes  

Microsoft Academic Search

Differentiation of sebocytes is strongly associated with enhanced lipid synthesis and accumulation in the cells. Liver X receptors (LXRs) are members of the nuclear receptor superfamily, which play a critical role in cholesterol homeostasis and lipid metabolism. We examined whether LXR? regulated lipid synthesis in the immortalized human sebaceous gland cell line SZ95. When the SZ95 sebocytes were treated with

Il Hong; Min-Ho Lee; Tae-Young Na; Christos C Zouboulis; Mi-Ock Lee



Lipid deacylating enzymes in plants: Old activities, new genes  

Microsoft Academic Search

Because lipids are major components of cellular membranes, their degradation under stress conditions compromises compartmentalization. However, in addition to having structural roles, membrane lipids are also implicated in signalling processes involving the activity of lipolytic enzymes. Phospholipases D and C, acting on the polar heads of phospholipids, have been relatively well characterized in plants. In contrast, knowledge of lipid deacylating

Ana Rita Matos; Anh-Thu Pham-Thi



Release and diffusional modeling of metronidazole lipid matrices  

Microsoft Academic Search

In this study, the first aim was to investigate the swelling and relaxation properties of lipid matrix on diffusional exponent (n). The second aim was to determine the desired release profile of metronidazole lipid matrix tablets. We prepared metronidazole lipid matrix granules using Carnauba wax, Beeswax, Stearic acid, Cutina HR, Precirol® ATO 5, and Compritol® ATO 888 by hot fusion

Mine Özyaz?c?; Evren H. Gökçe; Gökhan Ertan




Microsoft Academic Search

The development of lipid formulations of antifungal drugs has been a remarkable progress in the systemic antifungal arena. The lipid-based amphotericin B formulations; amphotericin B lipid complex (ABLC), amphotericin B colloidal dispersion (ABCD), and liposomal amphotericin B (L- AMB) have been in clinical use since the 1990s. They are significantly less nephrotoxic than the parent compound and can be safely



Lipid metabolism in regressing rat corpora lutea of pregnancy  

Microsoft Academic Search

Lipid accumulation is a hallmark of corpus luteum regression and we characterized lipids stored in rat corpora lutea of pregnancy between days 21 and 24 post coitum, the period of luteolysis. A 10-fold rise in lutein triglyceride concentrations occurred between days 2 1 and 24, which represented the major alteration in luteal lipid metabolism during luteolysis, coinciding with the ap-

J. F. Strauss; Eric Seifter; Eric L. Lien; David B. P. Goodman; R. L. Stambaugh


Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents  

Microsoft Academic Search

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions

N. A. Odintsova; N. V. Ageenko; K. V. Kiselev; N. M. Sanina; E. Y. Kostetsky



Curcuminoids-loaded lipid nanoparticles: Novel approach towards malaria treatment  

Microsoft Academic Search

In the present work, curcuminoids-loaded lipid nanoparticles for parenteral administration were successfully prepared by a nanoemulsion technique employing high-speed homogenizer and ultrasonic probe. For the production of nanoparticles, trimyristin, tristerin and glyceryl monostearate were selected as solid lipids and medium chain triglyceride (MCT) as liquid lipid. Scanning electron microscopy (SEM) revealed the spherical nature of the particles with sizes ranging

Aditya P. Nayak; Waree Tiyaboonchai; Swati Patankar; Basavaraj Madhusudhan; Eliana B. Souto



Lipid–protein interactions in biological membranes: A dynamic perspective  

Microsoft Academic Search

Though an increasing number of biological functions at the membrane are attributed to direct associations between lipid head groups and protein side chains or lipid protein hydrophobic attractive forces, surprisingly limited information is available about the dynamics of these interactions. The static in vitro representation provided by membrane protein structures, including very insightful lipid–protein binding geometries, still fails to recapitulate

Adam W. Smith


Linking lipids to Alzheimer's disease: cholesterol and beyond  

Microsoft Academic Search

Lipid-mediated signalling regulates a plethora of physiological processes, including crucial aspects of brain function. In addition, dysregulation of lipid pathways has been implicated in a growing number of neurodegenerative disorders, such as Alzheimer's disease (AD). Although much attention has been given to the link between cholesterol and AD pathogenesis, growing evidence suggests that other lipids, such as phosphoinositides and phosphatidic

Gilbert Di Paolo; Tae-Wan Kim



Phosphatidylinositol transfer proteins and cellular nanoreactors for lipid signaling  

Microsoft Academic Search

Membrane lipids function as structural molecules, reservoirs for second messengers, membrane platforms that scaffold protein assembly and regulators of enzymes and ion channels. Such diverse lipid functions contribute substantially to cellular mechanisms for fine-tuning membrane-signaling events. Meaningful coordination of these events requires exquisite spatial and temporal control of lipid metabolism and organization, and reliable mechanisms for specifically coupling these parameters

Kristina E Ile; Gabriel Schaaf; Vytas A Bankaitis



Chemical Changes in Lipids Produced by Thermal Processing.  

ERIC Educational Resources Information Center

|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)|

Nawar, Wassef W.



Review: Lipid and myoglobin oxidations in muscle foods  

Microsoft Academic Search

Lipid oxidation and myoglobin oxidation in muscle foods occur in a concurrent manner and each process appears to enhance the other. During oxidation of oxymyoglobin, both superoxide anion and hydrogen peroxide are produced and further react with iron to produce hydroxyl radical. The hydroxyl radical has the ability to penetrate into the hydrophobic lipid region and hence facilitates lipid oxidation.

Manat Chaijan


Anti-inflammatory properties of lipid oxidation products  

Microsoft Academic Search

Oxidative modification of lipids occurs during inflammatory processes and leads to the formation and accumulation of biologically active lipid oxidation products that induce specific cellular reactions. These reactions lead to a modulation of the inflammatory process and may determine the fate and outcome of the body's reaction in acute inflammation during host defense. The processes by which oxidized lipids may

Valery N. Bochkov; Norbert Leitinger



Peroxynitrite-mediated lipid oxidation and nitration: Mechanisms and consequences  

Microsoft Academic Search

Lipid oxidation and nitration represents a novel area of research of relevance in the understanding of inflammatory processes. Peroxynitrite, the product of the diffusion-limited reaction between nitric oxide and superoxide anion, mediates oxidative modifications in lipid systems including cell membranes and lipoproteins. In this review, we discuss the mechanisms of lipid oxidation and nitration by peroxynitrite as well as the

Homero Rubbo; Andrés Trostchansky; Valerie B. O’Donnell



Polymerized planar suspended lipid bilayers for single ion channel recordings: comparison of several dienoyl lipids.  


The stabilization of suspended planar lipid membranes, or black lipid membranes (BLMs), through polymerization of mono- and bis-functionalized dienoyl lipids was investigated. Electrical properties, including capacitance, conductance, and dielectric breakdown voltage, were determined for BLMs composed of mono-DenPC, bis-DenPC, mono-SorbPC, and bis-SorbPC both prior to and following photopolymerization, with diphytanoyl phosphocholine (DPhPC) serving as a control. Poly(lipid) BLMs exhibited significantly longer lifetimes and increased the stability of air-water transfers. BLM stability followed the order bis-DenPC > mono-DenPC ? mono-SorbPC > bis-SorbPC. The conductance of bis-SorbPC BLMs was significantly higher than that of the other lipids, which is attributed to a high density of hydrophilic pores, resulting in relatively unstable membranes. The use of poly(lipid) BLMs as matrices for supporting the activity of an ion channel protein (IC) was explored using ?-hemolysin (?-HL), a model IC. Characteristic i-V plots of ?-HL were maintained following photopolymerization of bis-DenPC, mono-DenPC, and mono-SorbPC, demonstrating the utility of these materials for preparing more durable BLMs for single-channel recordings of reconstituted ICs. PMID:21226498

Heitz, Benjamin A; Xu, Juhua; Jones, Ian W; Keogh, John P; Comi, Troy J; Hall, Henry K; Aspinwall, Craig A; Saavedra, S Scott



Nanostructured lipid carriers (NLCs) versus solid lipid nanoparticles (SLNs) for topical delivery of meloxicam.  


Abstract Objective: The aim of this study was to develop nanostructured lipid carriers (NLCs) as well as solid lipid nanoparticles (SLNs) and evaluate their potential in the topical delivery of meloxicam (MLX). Materials and methods: The effect of various compositional variations on their physicochemical properties was investigated. Furthermore, MLX-loaded lipid nanoparticles-based hydrogels were formulated and the gels were evaluated as vehicles for topical application. Results and discussion: The results showed that NLC and SLN dispersions had spherical shapes with an average size between 215 and 430?nm. High entrapment efficiency was obtained ranging from 61.94 to 90.38% with negatively charged zeta potential in the range of -19.1 to -25.7?mV. The release profiles of all formulations exhibited sustained release characteristics over 48?h and the release rates increased as the amount of liquid lipid in lipid core increased. Finally, Precirol NLC with 50% Miglyol® 812 and its corresponding SLN were incorporated in hydrogels. The gels showed adequate pH, non-Newtonian flow with shear-thinning behavior and controlled release profiles. The biological evaluation revealed that MLX-loaded NLC gel showed more pronounced effect compared to MLX-loaded SLN gel. Conclusion: It can be concluded that lipid nanoparticles represent promising particulate carriers for topical application. PMID:23528038

Khalil, Rawia M; Abd-Elbary, A; Kassem, Mahfoz A; Ghorab, Mamdouh M; Basha, Mona



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

PubMed Central

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

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



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


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

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



Effect of sodium molybdate on the status of lipids, lipid peroxidation and antioxidant systems in alloxan-induced diabetic rats  

Microsoft Academic Search

Background: Diabetes mellitus manifests itself in a wide variety of complications and the symptoms of the disease are multi-factorial. Methods: The lipid peroxidation (LPO) and antioxidant status were investigated in hemolysate, liver and kidney in alloxan-induced diabetic rats and the effect of molybdate supplementation on antioxidant defense systems. Results: Diabetic rats exhibited an increase in the levels of lipids, lipid

Saraswathi R. Panneerselvam; Swaminathan Govindasamy



Lipid class and fatty acid composition of brain lipids from Atlantic herring ( Clupea harengus ) at different stages of development  

Microsoft Academic Search

Little is known about the changes in composition of brain lipids and fatty acids at different stages of development in fish. Wild Atlantic herring (Clupea harengus L.) were collected from Loch Linnhe and the Firth of Clyde, Scotland, from August 1990 to March 1991. Lipid class and fatty acid compositions of brain lipids were studied at four different stages of

G. Mourente; D. R. Tocher



Studies on the compartmentation of lipid in adipose cells. I: Subcellular distribution, composition, and transport of newly synthesized lipid: liposomes  

Microsoft Academic Search

The subcellular distribution and composition of endogenously synthesized lipid in isolated white adipose cells were studied to determine the nature and extent of lipid compartmentation. After brief incubation of cells with labeled glucose, acetate, or palmitic acid, over 90% of newly syn- thesized triglyceride was localized in the bulk-lipid phase, indicating rapid intracellular transport and storage. From 13 to 20%




Quantitative proteomic analysis of B cell lipid rafts reveals that ezrin regulates antigen receptor–mediated lipid raft dynamics  

Microsoft Academic Search

Ligation of the B cell antigen receptor (BCR) with antigen induces lipid raft coalescence, a process that occurs after crosslinking of a variety of signaling receptors and is thought to potentiate cellular activation. To investigate lipid raft dynamics during BCR signaling, we quantitatively analyzed the B cell lipid raft proteome. BCR engagement induced dissociation of the adaptor protein ezrin from

Neetu Gupta; Bernd Wollscheid; Julian D Watts; Barbara Scheer; Ruedi Aebersold; Anthony L DeFranco



The biotin-capture lipid affinity assay: a rapid method for determining lipid binding parameters for apolipoproteins  

Microsoft Academic Search

The lipid affinity of plasma apolipoproteins is an important modulator of lipoprotein metabolism. Mutagen- esis techniques have been widely used to modulate apo- lipoprotein lipid affinity for studying biological function, but the approach requires rapid and reliable lipid affinity assays to compare the mutants. Here, we describe a novel method that measures apolipoprotein binding to a stan- dardized preparation of

W. Sean Davidson; Amy B. Ghering; Lauren Beish; Matthew R. Tubb; David Y. Hui; Kevin Pearson



Plasma lipases and lipid transfer proteins increase phospholipid but not free cholesterol transfer from lipid emulsion to high density lipoproteins  

Microsoft Academic Search

BACKGROUND: Plasma lipases and lipid transfer proteins are involved in the generation and speciation of high density lipoproteins. In this study we have examined the influence of plasma lipases and lipid transfer protein activities on the transfer of free cholesterol (FC) and phospholipids (PL) from lipid emulsion to human, rat and mouse lipoproteins. The effect of the lipases was verified

Valéria S Nunes; Eder CR Quintão; Patrícia M Cazita; Lila M Harada; Eliana C de Faria; Helena CF Oliveira



Lipid nanocapsules for dermal application: A comparative study of lipid-based versus polymer-based nanocarriers  

Microsoft Academic Search

Lipid nanocapsules (LNC) are colloidal carriers providing controlled release profiles and improved bioavailability for many drug substances and diverse administration routes. However, they have not been explored before for transdermal application. Here, we study the behavior of LNC as a transdermal drug delivery system using ibuprofen as a model drug. A comparison to other lipid nanocarriers such as solid lipid

Mona M. A. Abdel-Mottaleb; Dirk Neumann; Alf Lamprecht



Characterization of the Lateral Distribution of Fluorescent Lipid in Binary-Constituent Lipid Monolayers by Principal Component Analysis  

PubMed Central

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.

Sugar, Istvan P.; Zhai, Xiuhong; Boldyrev, Ivan A.; Molotkovsky, Julian G.; Brockman, Howard L.; Brown, Rhoderick E.



Functional lipids and lipoplexes for improved gene delivery  

PubMed Central

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.

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



[Phosphorescent analysis of lipid peroxidation products in liposomes].  


It was found that lipid peroxidation products incorporated into liposomes prepared from oxidized preparations of bovine heart phosphatidylcholine and the total lipid fraction of human erythrocyte membranes are able to phosphoresce at room temperature was studied. The temperature dependences of kinetic and spectral parameters of phosphorescence were measured. It is shown that mechanism of phosphorescence quenching of lipid chromophores has a dynamic nature. It is proposed to use endogenic molecules of the lipid peroxidation products capable of phosphorescence as intrinsic phosphorescence probes for studying the slow molecular dynamics of lipids in artificial and biological membranes in a millisecond range. PMID:10544819

Mazhul', V M; Shcherbin, D G


Jamming the endosomal system: lipid rafts and lysosomal storage diseases.  


Some lysosomal storage diseases result from the accumulation of lipids in degradative compartments of the endocytic pathway. Particularly striking is the example of the Niemann-Pick (NP) syndrome. NP syndromes types A and B are characterized by the accumulation of sphingomyelin, whereas cholesterol typically accumulates in NP type C. These two different lipids, sphingomyelin and cholesterol, are normal constituents of specific lipid microdomains called rafts. Because accumulation of raft lipids is observed not only in NP diseases but also in many other lipidoses, we forward the hypothesis that lysosomal storage diseases can be caused by the accumulation of lipid rafts in late endosomes/lysosomes. PMID:11050411

Simons, K; Gruenberg, J



Lipid composition of commercially canned single-strength orange juice  

Microsoft Academic Search

The lipid composition of commercially canned single-strength orange juice ranged from 84–101 mg\\/100 ml juice (overall mean\\u000a 95 6). Phospholipid phosphorus, expressed as mg\\/100 ml juice, showed a range of from 1.56–1.95, while phospholipid phosphorus\\/lipid\\u000a values (as g-P\\/mg lipid) were within a very narrow range, 18.9 1.1. The percentage distribution of lipid classes in these\\u000a juices was 24–35% neutral lipids,

Steven Nagy; Harold E. Nordby; John M. Smoot



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

Microsoft Academic Search

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

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



Eukaryotic Lipid Body Proteins in Oleogenous Actinomycetes and Their Targeting to Intracellular Triacylglycerol Inclusions: Impact on Models of Lipid Body Biogenesis  

Microsoft Academic Search

Bacterial neutral lipid inclusions are structurally related to eukaryotic lipid bodies. These lipid inclusions are composed of a matrix of triacylglycerols (TAGs) or wax esters surrounded by a monolayer of phospholipids. Whereas the monolayers of lipid bodies from animal and plant cells harbor specific classes of proteins which are involved in the structure of the inclusions and lipid homoestasis, no

Jan Hanisch; Marc Waltermann; Horst Robenek; Alexander Steinbuchel



The simulation approach to lipid-protein interactions.  


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

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



Lipid-Based Passivation in Nanofluidics  

PubMed Central

Stretching DNA in nanochannels is a useful tool for direct, visual studies of genomic DNA at the single molecule level. To facilitate the study of the interaction of linear DNA with proteins in nanochannels, we have implemented a highly effective passivation scheme based on lipid bilayers. We demonstrate virtually complete long-term passivation of nanochannel surfaces to a range of relevant reagents, including streptavidin-coated quantum dots, RecA proteins, and RecA–DNA complexes. We show that the performance of the lipid bilayer is significantly better than that of standard bovine serum albumin-based passivation. Finally, we show how the passivated devices allow us to monitor single DNA cleavage events during enzymatic degradation by DNase I. We expect that our approach will open up for detailed, systematic studies of a wide range of protein–DNA interactions with high spatial and temporal resolution.



Lipid-based passivation in nanofluidics.  


Stretching DNA in nanochannels is a useful tool for direct, visual studies of genomic DNA at the single molecule level. To facilitate the study of the interaction of linear DNA with proteins in nanochannels, we have implemented a highly effective passivation scheme based on lipid bilayers. We demonstrate virtually complete long-term passivation of nanochannel surfaces to a range of relevant reagents, including streptavidin-coated quantum dots, RecA proteins, and RecA-DNA complexes. We show that the performance of the lipid bilayer is significantly better than that of standard bovine serum albumin-based passivation. Finally, we show how the passivated devices allow us to monitor single DNA cleavage events during enzymatic degradation by DNase I. We expect that our approach will open up for detailed, systematic studies of a wide range of protein-DNA interactions with high spatial and temporal resolution. PMID:22432814

Persson, Fredrik; Fritzsche, Joachim; Mir, Kalim U; Modesti, Mauro; Westerlund, Fredrik; Tegenfeldt, Jonas O



Shape optimization in lipid nanotube networks  

NASA Astrophysics Data System (ADS)

Starting from a high surface free-energy state, lipid nanotube networks are capable to self-organize into tree-like structures with particular geometrical features. In this work we analyze the process of self-organization in such networks, and report a strong similarity to the Euclidian Steiner Tree Problem (ESTP). ESTP is a well-known NP-hard optimization problem of finding a network connecting a given set of terminal points on a plane, allowing addition of auxiliary points, with the overall objective to minimize the total network length. The present study shows that aggregate lipid structures self-organize into geometries that correspond to locally optimal solutions to such problems.

Lobovkina, T.; Dommersnes, P. G.; Tiourine, S.; Joanny, J.-F.; Orwar, O.



Lipid-Dependent Membrane Protein Topogenesis  

PubMed Central

The topology of polytopic membrane proteins is determined by topogenic sequences in the protein, protein-translocon interactions, and interactions during folding within the protein and between the protein and the lipid environment. Orientation of transmembrane domains is dependent on membrane phospholipid composition during initial assembly as well as on changes in lipid composition postassembly. The membrane translocation potential of negative amino acids working in opposition to the positive-inside rule is largely dampened by the normal presence of phosphatidylethanolamine, thus explaining the dominance of positive residues as retention signals. Phosphatidylethanolamine provides the appropriate charge density that permits the membrane surface to maintain a charge balance between membrane translocation and retention signals and also allows the presence of negative residues in the cytoplasmic face of proteins for other purposes.

Dowhan, William; Bogdanov, Mikhail



Sirtuins regulate key aspects of lipid metabolism.  


Members of the sirtuin family of NAD(+)-dependent protein deacetylases are important regulators of longevity in yeast, worms, and flies. Mammals have seven sirtuins (SIRT1-7), each characterized by differences in subcellular localization, substrate preference, and biological function. While it is unclear whether sirtuins regulate aging in mammals, it is clear that sirtuins influence diverse aspects of their metabolism. Indeed, SIRT1 promotes oxidation of fatty acids in liver and skeletal muscle, cholesterol metabolism in liver, and lipid mobilization in white adipose tissue. Moreover, small-molecule activators of SIRT1 have recently been shown to protect mice from the negative effects of a high-fat diet. These findings suggest that sirtuins might provide important new targets for the treatment of obesity and related diseases. In this review, we discuss the major findings linking sirtuins with the regulation of lipid metabolism. PMID:19962456

Lomb, David J; Laurent, Gaëlle; Haigis, Marcia C



Exercise Intensity Modulation of Hepatic Lipid Metabolism  

PubMed Central

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.

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



Amylose folding under the influence of lipids.  


The molecular dynamics simulation technique was used to study the folding and complexation process of a short amylose fragment in the presence of lipids. In aqueous solution, the amylose chain remains as an extended left-handed helix. After the addition of lipids in the system, however, we observe spontaneous folding of the amylose chain into a helical structure, with helical pitch and hydrogen bond network compatible with the V-amylose structure observed in X-ray experiments. Our results suggest that under the influence of external non polar ligands, the conformation of amylose undergoes a transition from an extended to a V-amylose structure in line with experimental evidence. PMID:23128420

López, Cesar A; de Vries, Alex H; Marrink, Siewert J



Content of lipids in finnish peat mires  

SciTech Connect

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

Fagernaes, L.; Ekman, R.



Theory of passive permeability through lipid bilayers.  


Recently measured water permeability through bilayers of different lipids is most strongly correlated with the area per lipid A rather than with other structural quantities such as the thickness. This paper presents a simple three-layer theory that incorporates the area dependence in a physically realistic way and also includes the thickness as a secondary modulating parameter. The theory also includes the well-known strong correlation of permeability upon the partition coefficients of general solutes in hydrocarbon environments (Overton's rule). Two mathematical treatments of the theory are given; one model uses discrete chemical kinetics and one model uses the Nernst-Planck continuum equation. The theory is fit to the recent experiments on water permeability in the accompanying paper. PMID:18166627

Nagle, John F; Mathai, John C; Zeidel, Mark L; Tristram-Nagle, Stephanie



Different stressors and blood lipid peroxidation.  


Elevation of lipid peroxidation (LOX) was observed in rabbits and mice after the intravenous administration of 0.2 of lipopolysaccharide (LPS) and 100 of peptidoglycan (MP). The peak was reached sooner after peptidoglycan, and 2-4 h after LPS administration. The trends of lipid peroxidation were the same in both species. 8-10 h later original LOX blood levels were reached. Mild horizontal vibration (1 h) induced in both species a significant lowering of LOX. This appeared already immediately after the vibration. Original values were gained again after 8-10 h. The difference between the internal stressors, LPS and MP, and the external stressor, vibration, are discussed. PMID:1781799

Lavický, J; Rasková, H



Lipid composition of serum lipoprotein in opisthorchiasis.  


Lipid composition (i.e. total cholesterol, free cholesterol, cholesteryl ester, triglycerides and phospholipids) in the individual serum lipoprotein fractions (i.e. high-density lipoprotein, low-density lipoprotein and very low-density lipoprotein) were studied in 24 healthy controls and 18 opisthorchiasis patients admitted to the Bangkok Hospital for Tropical Diseases, Faculty of Tropical Medicine. The two groups were similar in age range, sex ration and anthropometric data. Other background data such as blood pressure and alcohol consumption, were also similar in the two groups. All the patients had the habit of eating raw or half-cooked fish. Abnormalities of high-density lipoprotein content in the opisthorchiasis group showed as low cholesterol and cholesteryl ester concentrations but with high triglyceride concentrations. These may result from disturbance of the synthesis of nascent disk high-density lipoprotein or the removal of lipid content in lipoproteins. PMID:3250339

Changbumrung, S; Ratarasarn, S; Hongtong, K; Migasena, P; Vutikes, S; Migasena, S



Abnormal lipid metabolism and renal disorders.  


Abnormal renal diseases including nephrotic syndrome and chronic renal failure are associated with hyperlipidemia, significance of abnormal lipid metabolism has been thought to be limited in some inherited renal diseases. However, recent studies have postulated that glomerulosclerosis is induced by hyperlipidemia and is in common with atherosclerosis. This involvement is found in the progressive renal disorders, e.g., focal glomerular sclerosis, diabetic nephropathy and glycogen storage disease. Interaction between macrophages and mesangial cells may play an important role in such conditions. This evidence is supported by experimental models with hyperlipidemia. On the other hand, discovery and new hereditary metabolic disorders, such as type III hyperlipoproteinemia and lipoprotein glomerulopathy, shows that apolipoprotein (apo) E abnormalities are responsible for the glomerular lesions. Especially, lipoprotein glomerulopathy has specific features different from those of lipid-induced renal diseases. In this disease, apo E Sendai which results from new substitution (Arginine 145-->Proline) may induce intraglomerular lipoprotein thrombi characteristic of lipoprotein glomerulopathy. PMID:9163848

Saito, T



Hot-melt coating with lipid excipients.  


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

Jannin, Vincent; Cuppok, Yvonne



Lipid signaling: Sleep, synaptic plasticity, and neuroprotection  

Microsoft Academic Search

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,

Chu Chen; Nicolas G. Bazan



Inhibition of lipid oxidation by carnosine  

Microsoft Academic Search

The antioxidant activity of carnosine, a ?-alanine-histidine dipeptide found in skeletal muscle, was investigated. Carnosine\\u000a (25 mM) inhibited the catalysis of lipid oxidation by iron, hemoglobin, lipoxidase and singlet oxygen from 35–96% suggesting\\u000a that the antioxidant mechanism of carnosine is not solely due to metal chelation. Heating the carnosine at 100°C for 15 min\\u000a had no effect on its ability

Eric A. Decker; Habibollah Faraji



Skin lipids of the Florida indigo snake  

Microsoft Academic Search

Cast skins of the Florida indigo snake (Drymarchon corais) yielded up to 8% chloroform: methanol-extractable lipid, which was found to contain methyl ketones (20%), free secondary\\u000a alcohols (15%), free primary alcohols (30%), free cholesterol (15%), free fatty acids (5%), and hydrocarbons (5%). The hydrocarbons\\u000a appeared to be contaminants, because gas chromatography revealed a distribution characteristic of petroleum hydrocarbons.\\u000a The methyl

David G. Ahern; Donald T. Downing



Diffusion of macromolecules on lipid vesicles  

NASA Astrophysics Data System (ADS)

Diffusion of macromolecules on a surface of lipid vesicles of different reduced volume and geometry is investigated. It is assumed that the macromolecules deform the surface of the vesicles by inducing the spontaneous curvature which is proportional to their concentration. We study how nonuniform distribution of macromolecules is reflected in the shape of the vesicles and how the shape of the vesicles influences the diffusion process.

Gó?d?, W. T.



Sensitive profiling of chemically diverse bioactive lipids  

Microsoft Academic Search

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

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



Lipid chain mobility in interdigitated DPPC systems  

Microsoft Academic Search

The segmental lipid chain mobility in the gel phase of dipalmitoylphosphatidylcholine (DPPC) multilayers dispersed in buffer\\u000a and in the interdigitated gel phase induced by glycerol, ethylene glycol, ethanol and chaotropic salt NaClO4 was compared by using conventional electron spin resonance (ESR) spectroscopy. The stearic acids bearing the nitroxide moiety\\u000a at different positions down the acyl chain (n-NSA,n-5, 7, 10, 12

R. Bartucci; G. Montesano; L. Sportelli



Lipid modulation of neuronal cholinergic activity  

SciTech Connect

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.

Bottiglieri, D.F.



Postprandial lipid oxidation and cardiovascular disease risk  

Microsoft Academic Search

A mild pro-oxidative state accompanies meal ingestion, which results in an increase in biomarkers of inflammation, adhesion,\\u000a and endothelial dysfunction, all of which are factors in the development of cardiovascular disease. Both fat and carbohydrate\\u000a can cause the effect, which is additive and exacerbated by diabetes. The presence of lipid, glucose, and cholesterol oxidation\\u000a products of dietary or endogenous origin

Phyllis E. Bowen; Gayatri Borthakur



An unidentified lipid prevalent in tumors  

Microsoft Academic Search

An unidentified lipid was found in five different tumor sources. It was not found in liver, bone marrow or plasma from tumor-bearing\\u000a animals, nor in the extracellular fluid supporting growth of Ehrlich ascites cells. The polarity of the unidentified component\\u000a was similar to that of a glyceryl ether diester, and it was isolated in milligram amounts by preparative thinlayer chromatography.

Fred Snyder; Edgar A. Cress; Nelson Stephens



Bioorganic chemistry of plant lipid desaturation  

Microsoft Academic Search

The desaturation of long-chain fatty acids is a ubiquitous biotransformation which plays a critical role in the biosynthesis of plant lipids. Species-specific variations lead to unusual fatty acid signatures. Of particular interest is the unique ability of desaturases to oxidize unactivated hydrocarbon chains in such a chemo-, regio- and stereoselective manner. As part of ongoing research into the structure\\/activity relationships

B. Behrouzian; P. H. Buist



Light scattering characterization of extruded lipid vesicles  

Microsoft Academic Search

By modeling extruded unilamellar lipid vesicles as thin-walled ellipsoidal shells, mathematical analysis provides simple\\u000a equations which relate the mean elongation and other morphological characteristics of a vesicle population to quantities readily\\u000a obtained from combined static and dynamic light scattering measurements. For SOPC vesicles extruded through a 100 nm pore-size\\u000a filter into a 72.9 mm NaCl solution, the inferred elongation ratio

Albert J. Jin; Daniel Huster; Klaus Gawrisch; Ralph Nossal



ABC proteins: key molecules for lipid homeostasis  

Microsoft Academic Search

Forty-nine ABC protein genes exist on human chromosomes. Eukaryotic ABC proteins were originally recognized as drug efflux pumps involved in the multidrug resistance of cancer cells. However, it is now realized that one of their major physiological roles is cellular lipid transport and homeostasis, and their dysfunction is often associated with human diseases. ABCA1 and ABCA7 mediate the apolipoprotein-dependent formation

Kei Takahashi; Yasuhisa Kimura; Koh Nagata; Akitsugu Yamamoto; Michinori Matsuo; Kazumitsu Ueda



Membrane Lipid Biosynthesis in Purple Bacteria  

Microsoft Academic Search

Membranes are essential to all living cells. They provide the boundary to the surrounding environment, allow the controlled\\u000a exchange of compounds through membrane transporters, and serve as a matrix for membrane associated enzymes and protein complexes\\u000a involved in the generation of energy or communication with the environment. Biomembranes are built from amphipathic, polar\\u000a lipids that either on their own or

Banita Tamot; Christoph Benning


Structural characterization of cationic lipid-tRNA complexes  

PubMed Central

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.

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



Lipid emulsion for local anesthetic systemic toxicity.  


The accidental overdose of local anesthetics may prove fatal. The commonly used amide local anesthetics have varying adverse effects on the myocardium, and beyond a certain dose all are capable of causing death. Local anesthetics are the most frequently used drugs amongst anesthetists and although uncommon, local anaesthetic systemic toxicity accounts for a high proportion of mortality, with local anaesthetic-induced cardiac arrest particularly resistant to standard resuscitation methods. Over the last decade, there has been convincing evidence of intravenous lipid emulsions as a rescue in local anesthetic-cardiotoxicity, and anesthetic organisations, over the globe have developed guidelines on the use of this drug. Despite this, awareness amongst practitioners appears to be lacking. All who use local anesthetics in their practice should have an appreciation of patients at high risk of toxicity, early symptoms and signs of toxicity, preventative measures when using local anesthetics, and the initial management of systemic toxicity with intravenous lipid emulsion. In this paper we intend to discuss the pharmacology and pathophysiology of local anesthetics and toxicity, and the rationale for lipid emulsion therapy. PMID:21969824

Ciechanowicz, Sarah; Patil, Vinod



Intravenous lipid emulsion - rescued at LAST.  


The accidental overdose of local anaesthetics may prove fatal. The commonly used amide local anaesthetics have varying adverse effects on the myocardium and beyond a certain dose all are capable of causing death. Local anaesthetics are the most frequently used drugs in dentistry and although uncommon, local anaesthetic systemic toxicity (LAST) accounts for a high proportion of mortalities in the dental office, with local anaesthetic-induced cardiac arrest particularly resistant to standard resuscitation methods. Over the last decade there has been convincing evidence of using intravenous lipid emulsions as a rescue in local anaesthetic - cardiotoxicity and anaesthetic organisations over the globe have developed guidelines on the use of this drug. Despite this, however, awareness among practitioners appears to be lacking. All who use local anaesthetics in their practice should have an appreciation of patients at high risk of toxicity, early symptoms and signs of toxicity, preventative measures when using these drugs and the initial management of systemic toxicity with intravenous lipid emulsion. In this review we intend to discuss the pharmacology and pathophysiology of local anaesthetic toxicity, and the rationale for intravenous lipid emulsion therapy. PMID:22402543

Ciechanowicz, S J; Patil, V K



Hydrophobic Mismatch between Helices and Lipid Bilayers  

PubMed Central

?-Helical transmembrane peptides, named WALP, with a hydrophobic sequence of leucine and alanine of varying length bordered at both ends by two tryptophans as membrane anchors, were synthesized to study the effect of hydrophobic matching in lipid bilayers. WALPs of 13-, 16-, and 19-residues were incorporated into 1,2-dilauroyl-sn-glycero-3-phosphocholine (12C), 1,2-tridecanoyl-sn-glycero-3-phosphocholine (13C), and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (14C) bilayers in the form of oriented multilayers. Oriented circular dichroism spectra and x-ray diffraction patterns showed that the peptides were homogenously distributed in the lipid bilayers with the helical axes oriented approximately normal to the plane of bilayers. But in all cases, x-ray diffraction showed that the peptides did not alter the thickness of the bilayer. This is contrary to the case of gramicidin where 1,2-dimyristoyl-sn-glycero-3-phosphocholine and 1,2-dilauroyl-sn-glycero-3-phosphocholine clearly thinned and thickened, respectively, to approach the hydrophobic thickness of the gramicidin channels. The result seems to indicate that the packing of lipid chains around a single helix is fundamentally different from the way the chains pack against a large protein surface.

Weiss, Thomas M.; van der Wel, Patrick C. A.; Killian, J. Antoinette; Koeppe, Roger E.; Huang, Huey W.



Crystallizing Membrane Proteins Using Lipidic Mesophases  

PubMed Central

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

Caffrey, Martin; Cherezov, Vadim



Modeling the induction of lipid membrane electropermeabilization.  


Experiments show significant effects of an electric field on lipid membrane, leading to a pore formation when a high intensity field is applied. The phenomenon of electroporation is preceded by the induction and expansion of defects, responsible for the pre-pore excitation. We examine the mechanism of the induction of the field-driven defects by Monte Carlo simulations. The study is based on the improved Pink's model, which includes explicit interactions between the polar heads and energy of interactions between the heads and the field. No anomalous deformation of the molecules is considered. The study, provided for bilayer dipalmitoyl-phosphatidylcholine (DPPC) membrane in the gel (300 K) and fluid (330 K) phases, shows dependence of the membrane conformational and energetical state on the value of the electric field. We observe that the electric field affects the number of molecules in the gel and in the fluid states. In the layer at the negative potential, when the transmembrane voltage is above U(c) approximately 280 mV, lipid heads abruptly reorient and the number of local spots with fluid conformation increases. The other layer slightly tends to tighten its structure, producing additional mechanical stress between layers. Lipids showed complete insensitivity to the electric field within physiological limits, U<70 mV. PMID:16731051

Kotulska, Malgorzata; Kubica, Krystian; Koronkiewicz, Stanislawa; Kalinowski, Slawomir



Pharmacotherapies for lipid modification: beyond the statins.  


The widespread clinical use of statins has contributed to significant reductions in the rate of cardiovascular morbidity and mortality over the past 3 decades, and statins are considered first-line therapy for the prevention and treatment of atherosclerotic vascular disease. Nevertheless, various other lipid-lowering agents can provide clinical benefit by supplementing or augmenting statin therapy in patients with severe hypercholesterolaemia or mixed dyslipidaemia, or by providing an alternative for patients who are intolerant to statins. Bile acid resins and niacin were prescribed for lipid modification for years before the introduction of the statins, and new data continue to emerge regarding their use in different patient groups and for specific conditions. Ezetimibe can be appropriate for patients whose primary lipid abnormality is an elevated LDL-cholesterol level, whereas the fibrates seem to be most beneficial in patients with low levels of HDL cholesterol and elevated triglycerides. At the end of 2012 and the beginning of 2013, the first microsomal triglyceride transfer protein inhibitor, lomitapide, and the first antisense therapy to target apolipoprotein B, mipomersen, were approved for the treatment of individuals with extremely elevated LDL-cholesterol levels caused by homozygous familial hypercholesterolaemia. Although two agents in the experimental class of cholesteryl ester transfer protein inhibitors have failed to show a benefit in clinical trials, newer drugs in this class could provide an additional strategy to address residual cardiovascular risk in patients treated with statins. PMID:23959229

Gotto, Antonio M; Moon, Jennifer E



Backbone Dynamics Of Intracellular Lipid Binding Proteins  

NASA Astrophysics Data System (ADS)

The family of intracellular lipid binding proteins (iLBPs) comprises a group of homologous 14-15 kDa proteins that specifically bind and facilitate the transport of fatty acids, bile acids, retinoids or eicosanoids. Members of this family include several types of fatty acid binding proteins (FABPs), ileal lipid binding protein, cellular retinoic acid binding proteins and cellular retinoid binding proteins. As a contribution to understanding the structure-function relationship in this protein family, the solution structure and backbone dynamics of human epidermal-type FABP (E-FABP) determined by NMR spectroscopy are reported. Moreover, hydrogen/deuterium exchange experiments indicated a direct correlation between the stability of the hydrogen-bonding network in the ?-sheet structure and the conformational exchange in the millisecond-to-microsecond time range. The features of E-FABP backbone dynamics discussed in the present study are compared with those obtained for other phylogenetically related proteins. A strong interdependence with the overall protein stability and possibly also with the ligand-binding affinity for members of the lipid-binding protein family is shown.

Gutiérrez-González, Luis H.



Assays for the measurement of lipid peroxidation.  


Physical and emotional stress, metabolic alterations, carcinogenesis or inflammation are conditions that can trigger oxidative stress, which is defined as a balance shift of redox reactions towards oxidation, resulting in the increase of reactive oxygen species (ROS). ROS are continuously formed in small quantities during the normal metabolism of cell, however the overproduction of ROS is cytotoxic and damages macromolecules (DNA, proteins, sugars and lipids). Polyunsaturated fatty acids (PUFAs) that are esterified in membrane or storage lipids are subject to ROS-induced pero