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1

Chemical requirements for inhibition of gap junction communication by the biologically active lipid oleamide  

PubMed Central

Oleamide is an endogenous fatty acid primary amide that possesses sleep-inducing properties in animals and has been shown to effect serotonergic systems and block gap junction communication in a structurally specific manner. Herein, the structural features of oleamide required for inhibition of the gap junction-mediated chemical and electrical transmission in rat glial cells are defined. The effective inhibitors fall into two classes of fatty acid primary amides of which oleamide and arachidonamide are the prototypical members. Of these two, oleamide constitutes the most effective, and its structural requirements for inhibition of the gap junction are well defined. It requires a chain length of 16–24 carbons of which 16–18 carbons appears optimal, a polarized terminal carbonyl group capable of accepting but not necessarily donating a hydrogen bond, a ?9 cis double bond, and a hydrophobic methyl terminus. Within these constraints, a range of modifications are possible, many of which may be expected to improve in vivo properties. A select set of agents has been identified that serves both as oleamide agonists and as inhibitors of fatty acid amide hydrolase, which is responsible for the rapid inactivation of oleamide.

Boger, Dale L.; Patterson, Jean E.; Guan, Xiaojun; Cravatt, Benjamin F.; Lerner, Richard A.; Gilula, Norton B.

1998-01-01

2

Oleamide: a member of the endocannabinoid family?  

PubMed Central

The fatty acid amide class of compounds, which include the endocannabinoid anandamide and the sleep-inducing compound oleamide, have been shown in vitro to have a multiplicity of actions upon different neurochemical systems. In the present issue of this journal, Leggett et al present data indicating that oleamide functionally activates CB1 cannabinoid receptors in vitro. The significance of their finding is discussed in this commentary.

Fowler, Christopher J

2003-01-01

3

Exceptionally potent inhibitors of fatty acid amide hydrolase: The enzyme responsible for degradation of endogenous oleamide and anandamide  

PubMed Central

The development of exceptionally potent inhibitors of fatty acid amide hydrolase (FAAH), the enzyme responsible for the degradation of oleamide (an endogenous sleep-inducing lipid), and anandamide (an endogenous ligand for cannabinoid receptors) is detailed. The inhibitors may serve as useful tools to clarify the role of endogenous oleamide and anandamide and may prove to be useful therapeutic agents for the treatment of sleep disorders or pain. The combination of several features—an optimal C12–C8 chain length, ?-unsaturation introduction at the corresponding arachidonoyl ?8,9/?11,12 and oleoyl ?9,10 location, and an ?-keto N4 oxazolopyridine with incorporation of a second weakly basic nitrogen provided FAAH inhibitors with Kis that drop below 200 pM and are 102–103 times more potent than the corresponding trifluoromethyl ketones.

Boger, Dale L.; Sato, Haruhiko; Lerner, Aaron E.; Hedrick, Michael P.; Fecik, Robert A.; Miyauchi, Hiroshi; Wilkie, Gordon D.; Austin, Bryce J.; Patricelli, Matthew P.; Cravatt, Benjamin F.

2000-01-01

4

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.

2006-01-01

5

Modification of 5HT 2 receptor mediated behaviour in the rat by oleamide and the role of cannabinoid receptors  

Microsoft Academic Search

Oleamide (cis-9,10-octadecenoamide) is an endogenous brain lipid which has been suggested to induce sleep in experimental animals. The mechanism of action is unclear but shares many of the characteristics of endogenous cannabinoids such as anandamide and has been shown to enhance in vitro responses to 5-HT and GABA. In the present study we investigated the effects of oleamide on two

J. F Cheer; A.-K Cadogan; C. A Marsden; K. C. F Fone; D. A Kendall

1999-01-01

6

Allosteric regulation by oleamide of the binding properties of 5-hydroxytryptamine7 receptors.  

PubMed

Oleamide belongs to a family of amidated lipids with diverse biological activities, including sleep induction and signaling modulation of several 5-hydroxytryptamine (5-HT) receptor subtypes, including 5-HT1A, 5-HT2A/2C, and 5-HT7. The 5-HT7 receptor, predominantly localized in the hypothalamus, hippocampus, and frontal cortex, stimulates cyclic AMP formation and is thought to be involved in the regulation of sleep-wake cycles. Recently, it was proposed that oleamide acts at an allosteric site on the 5-HT7 receptor to regulate cyclic AMP formation. We have further investigated the interaction between oleamide and 5-HT7 receptors by performing radioligand binding assays with HeLa cells transfected with the 5-HT7 receptor. Methiothepin, clozapine, and 5-HT all displaced specific [3H]5-HT (100 nM) binding, with pK(D) values of 7.55, 7.85, and 8.39, respectively. Oleamide also displaced [3H]5-HT binding, but the maximum inhibition was only 40% of the binding. Taking allosteric (see below) cooperativity into account, a K(D) of 2.69 nM was calculated for oleamide. In saturation binding experiments, oleamide caused a 3-fold decrease in the affinity of [3H]5-HT for the 5-HT7 receptor, without affecting the number of binding sites. A Schild analysis showed that the induced shift in affinity of [3H]5-HT reached a plateau, unlike that of a competitive inhibitor, illustrating the allosteric nature of the interaction between oleamide and the 5-HT7 receptor. Oleic acid, the product of oleamide hydrolysis, had a similar effect on [3H]5-HT binding, whereas structural analogs of oleamide, trans-9,10-octadecenamide, cis-8,9-octadecenamide, and erucamide, did not alter [3H]5-HT binding significantly. The findings support the hypothesis that oleamide acts via an allosteric site on the 5-HT7 receptor regulating receptor affinity. PMID:10571256

Hedlund, P B; Carson, M J; Sutcliffe, J G; Thomas, E A

1999-12-01

7

Unique allosteric regulation of 5-hydroxytryptamine receptor-mediated signal transduction by oleamide  

PubMed Central

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 lower efficacy than that observed by 5HT. This effect was not observed in untransfected HeLa cells. Clozapine did not prevent the increase in cAMP elicited by oleamide, and ketanserin caused an ?65% decrease. In the presence of 5HT, oleamide had the opposite effect on cAMP, causing insurmountable antagonism of the concentration-effect curve to 5HT, but had no effect on cAMP levels elicited by isoproterenol or forskolin. These results indicate that oleamide can modulate 5HT-mediated signal transduction at different subtypes of mammalian 5HT receptors. Additionally, our data indicate that oleamide acts at an apparent allosteric site on the 5HT7 receptor and elicits functional responses via activation of this site. This represents a unique mechanism of activation for 5HT G protein-coupled receptors and suggests that G protein-coupled neurotransmitter receptors may act like their iontropic counterparts (i.e., ?-aminobutyric acid type A receptors) in that there may be several binding sites on the receptor that regulate functional activity with varying efficacies.

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

1997-01-01

8

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

2001-01-01

9

Allosteric regulation by oleamide of the binding properties of 5-hydroxytryptamine 7 receptors  

Microsoft Academic Search

Oleamide belongs to a family of amidated lipids with diverse biological activities, including sleep induction and signaling modulation of several 5-hydroxytryptamine (5-HT) receptor subtypes, including 5-HT1A, 5-HT2A\\/2C, and 5-HT7. The 5-HT7 receptor, predominantly localized in the hypothalamus, hippocampus, and frontal cortex, stimulates cyclic AMP formation and is thought to be involved in the regulation of sleep–wake cycles. Recently, it was

Peter B Hedlund; Monica J Carson; J. Gregor Sutcliffe; Elizabeth A Thomas

1999-01-01

10

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: yslee@kcch.re.kr

2006-04-01

11

Enhanced vasorelaxant effects of the endocannabinoid-like mediator, oleamide, in hypertension.  

PubMed

Oleamide is an endocannabinoid-like, fatty acid amide with structural similarities to anandamide. The cardiovascular effects of anandamide are enhanced in hypertension and we have now examined how hypertension affects responses to oleamide. Vasorelaxant responses to oleamide were significantly (P<0.001) enhanced in aortic rings from spontaneously hypertensive rats (SHRs), such that the maximal relaxation to oleamide was 40.3 ± 3.5%, compared to 15.7 ± 3.9% in normotensive Wistar Kyoto (WKY) controls. The augmented responses to oleamide in SHR arteries were unaffected by either inhibition of nitric oxide synthase (300 ?M l-NAME) or fatty acid amide hydrolase (1 ?M URB597) and independent of cannabinoid CB(1) receptors or the endothelium. The enhanced responses to oleamide were opposed by pre-treatment with capsaicin (such that R(max) was reduced to 9.8 ± 1.5%) and this occurred independently of TRPV1 receptor and sensory nerve activity, as the TRPV1 antagonist capsazepine (1-5 ?M) and the cation channel inhibitor ruthenium red (10 ?M) had no effect on the responses to oleamide. However, inhibition of cyclooxygenase (10 ?M indomethacin) enhanced the responses in the WKY aortae, such that the responses were comparable to those in the SHR. The results suggest that the cyclooxygenase pathway has a role in modulating vasorelaxation caused by oleamide in normotensive aortae and that this is lost in hypertension, possibly as an adaptation to the increase in blood pressure. PMID:22465182

Hopps, Jamie J; Dunn, William R; Randall, Michael D

2012-06-01

12

Determination of oleamide and erucamide in polyethylene films by pressurised fluid extraction and gas chromatography.  

PubMed

A pressurized fluid extraction (PFE) and gas chromatography-flame ionization detection (GC-FID) method is proposed to determine the slip agents in polyethylene (PE) films. The study of PFE variables was performed using a fractional factorial design (FFD) for screening and a central composite design (CCD) for optimizing the main variables obtained from the Pareto charts. The variables that were studied include temperature, static time, percentage of cyclohexane and the number of extraction cycles. The final condition selected was pure isopropanol (two times) at 105 degrees C for 16min. The recovery of spiked oleamide and erucamide was around 100%. The repeatability of the method was between 9.6% for oleamide and 8% for erucamide, expressed as relative standard deviation. Finally, the method was applied to determine oleamide and erucamide in several polyethylene films and the results were statistically equal to those obtained by pyrolysis and gas-phase chemiluminescence (CL). PMID:16716333

Garrido-López, Alvaro; Esquiu, Vanesa; Tena, María Teresa

2006-08-18

13

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

2006-01-01

14

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

PubMed

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 microM, 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 microM, 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 microM, Rmax=58.4+/-1.9%, n=5; P<0.05). Desensitisation of vanilloid receptors with capsaicin (10 microM for 30 min) shifted the oleamide concentration-response curve approximately 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 microM, Rmax=66.8+/-4.5%, n=6; P<0.01). Rimonabant (CB1 cannabinoid receptor antagonist; SR141716A; 3 microM) significantly inhibited relaxation induced by oleamide (EC50=3.5+/-0.3 microM, Rmax=75.1+/-1.9%; n=8; P<0.05). In contrast, neither the more selective CB1 receptor antagonist, AM251 (1 microM), nor the CB2 antagonist, SR144528 (1 microM), had significant effects. O-1918 (10 microM), 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 (KC)) and involve capsaicin-sensitive sensory nerves. Oleamide may share a receptor (sensitive to rimonabant and O-1918, and coupled to KC) 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. PMID:16415907

Hoi, Pui Man; Hiley, C Robin

2006-03-01

15

Metabolic features of the adaptive effect of delta-sleep inducing peptide and piracetam under hyperoxic conditions.  

PubMed

Adaptive effects of delta-sleep inducing peptide (DSIP, 12 microgram/100 g body weight, single intraperitoneal injection) and piracetam (3 mg/100 g body weight, daily intraperitoneal injection for 3 days) are manifested via differential changes in neurotransmitter amino acids (GABA, glutamate, aspartate), modulation of transport ATPase activity, and decreased accumulation of lipid peroxidation products (conjugated dienes, malonic dialdehyde, Schiff bases) in various fractions of neuronal membranes (myelin, synaptic and mitochondrial membranes) in the sensomotor cortex of rat brain. Under hyperbaric oxygenation (0.3 MPa for 2 h), the combination of DSIP and piracetam enhanced the protective effect of each compound. PMID:10395980

Lysenko, A V; Alperovich, D V; Uskova, N I; Mendzheritsky, A M

1999-06-01

16

Enzymatic synthesis of delta sleep-inducing peptide.  

PubMed

The delta sleep-inducing peptide was assembled enzymatically from three tripeptide fragments. All the peptide bonds were prepared by either papain- or alpha-chymotrypsin-mediated synthesis. Secondary hydrolysis was suppressed by introducing N alpha-protected amino acid or peptide esters as carboxyl components and using an alkaline pH. The protected nonapeptide was oxidized with ferric chloride to deprotect the C-terminal phenylhydrazide and then hydrogenated. The homogeneous peptide was obtained by reversed phase high-performance liquid chromatography. Comparison of enzymatic and chemical preparations showed no obvious differences. PMID:3366553

Sakina, K; Kawazura, K; Morihara, K

1988-02-01

17

Oleamide activates peroxisome proliferator-activated receptor gamma (PPAR?) in vitro  

PubMed Central

Background Oleamide (ODA) is a fatty acid primary amide first identified in the cerebrospinal fluid of sleep-deprived cats, which exerts effects on vascular and neuronal tissues, with a variety of molecular targets including cannabinoid receptors and gap junctions. It has recently been reported to exert a hypolipidemic effect in hamsters. Here, we have investigated the nuclear receptor family of peroxisome proliferator-activated receptors (PPARs) as potential targets for ODA action. Results Activation of PPAR?, PPAR? and PPAR? was assessed using recombinant expression in Chinese hamster ovary cells with a luciferase reporter gene assay. Direct binding of ODA to the ligand binding domain of each of the three PPARs was monitored in a cell-free fluorescent ligand competition assay. A well-established assay of PPAR? activity, the differentiation of 3T3-L1 murine fibroblasts into adipocytes, was assessed using an Oil Red O uptake-based assay. ODA, at 10 and 50??M, was able to transactivate PPAR?, PPAR? and PPAR? receptors. ODA bound to the ligand binding domain of all three PPARs, although complete displacement of fluorescent ligand was only evident for PPAR?, at which an IC50 value of 38??M was estimated. In 3T3-L1 cells, ODA, at 10 and 20??M, induced adipogenesis. Conclusions We have, therefore, identified a novel site of action of ODA through PPAR nuclear receptors and shown how ODA should be considered as a weak PPAR? ligand in vitro.

2012-01-01

18

The influence of the delta-sleep-inducing peptide on convulsive activity  

Microsoft Academic Search

Data are presented in this paper on the influence of the delta-sleep-inducing peptide (DSIP) on various forms of convulsive activity. The capacity of this peptide to suppress convulsive activity in foci created in the cerebral cortex by the application of strychnine has been demonstrated in experiments on cats. It has been established in experiments on rats that DSIP determines the

A. A. Shandra; L. S. Godlevskii; A. M. Mazarati; A. A. Oleshko; I. I. Mikhaleva

1993-01-01

19

Nasal Continuous Positive Airway Pressure Reduces Sleep-induced Blood Pressure Increments In Preeclampsia  

Microsoft Academic Search

Preeclampsia is the predominant cause of admissions to neonatal intensive care. The diurnal blood pressure pattern is flattened or reversed in preeclampsia. We hypothesized that snoring and par- tial upper airway obstruction contribute to nocturnal rises in blood pressure. We tested this hypothesis by controlling sleep- induced upper airway flow limitation and snoring with nasal posi- tive pressure. Eleven women

N. EDWARDS; D. M. BLYTON; T. KIRJAVAINEN; G. J. KESBY; C. E. SULLIVAN

20

Oleamide is a selective endogenous agonist of rat and human CB1 cannabinoid receptors  

PubMed Central

The ability of the endogenous fatty acid amide, cis-oleamide (ODA), to bind to and activate cannabinoid CB1 and CB2 receptors was investigated. ODA competitively inhibited binding of the nonselective cannabinoid agonist [3H]CP55,940 and the selective CB1 antagonist [3H]SR141716A to rat whole-brain membranes with Ki values of 1.14 ?M (0.52–2.53 ?M, Hill slope=0.80, n=6) and 2.63 ?M (0.62–11.20 ?M, Hill slope=0.92, n=4), respectively. AEA inhibited [3H]CP55,940 binding in rat whole-brain membranes with a Ki of 428 nM (346–510 nM, Hill slope=?1.33, n=3). ODA competitively inhibited [3H]CP55,940 binding in human CB1 (hCB1) cell membranes with a Ki value of 8.13 ?M (4.97–13.32 ?M, n=2). In human CB2 transfected (hCB2) HEK-293T cell membranes, 100 ?M ODA produced only a partial (42.5±7%) inhibition of [3H]CP55,940 binding. ODA stimulated [35S]GTP?S binding in a concentration-dependent manner (EC50=1.64 ?M (0.29–9.32 ?M), R2=0.99, n=4–9), with maximal stimulation of 188±9% of basal at 100 ?M. AEA stimulated [35S]GTP?S binding with an EC50 of 10.43 ?M (4.45–24.42 ?M, R2=1.00, n=3, 195±4% of basal at 300 ?M). Trans-oleamide (trans-ODA) failed to significantly stimulate [35S]GTP?S binding at concentrations up to 100 ?M. ODA (10 ?M)-stimulated [35S]GTP?S binding was reversed by the selective CB1 antagonist SR141716A (IC50=2.11 nM (0.32–13.77 nM), R2=1.00, n=6). The anatomical distribution of ODA-stimulated [35S]GTP?S binding in rat brain sections was indistinguishable from that of HU210. Increases of similar magnitude were observed due to both agonists in the striatum, cortex, hippocampus and cerebellum. ODA (10 ?M) significantly inhibited forskolin-stimulated cyclic AMP (cAMP) accumulation in mouse neuroblastoma N1E 115 cells (P=0.02, n=11). ODA-mediated inhibition was completely reversed by 1 ?M SR141716A (P<0.001, n=11) and was also reversed by pretreatment with 300 ng ml?1 pertussis toxin (P<0.001, n=6). These data demonstrate that ODA is a full cannabinoid CB1 receptor agonist. Therefore, in addition to allosteric modulation of other receptors and possible entourage effects due to fatty acid amide hydrolase inhibition, the effects of ODA may be mediated directly via the CB1 receptor.

Leggett, James D; Aspley, S; Beckett, S R G; D'Antona, A M; Kendall, D A; Kendall, D A

2004-01-01

21

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

Microsoft Academic Search

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

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

2004-01-01

22

Lipids  

NSDL National Science Digital Library

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

Anderson, Paul

2013-03-12

23

Interaction of Delta Sleep-inducing Peptide and Valproate on Metaphit Audiogenic Seizure Model in Rats  

Microsoft Academic Search

Effects of valproate (VPA), a conventional antiepileptic drug and natural delta sleep-inducing peptide (DSIP) on metaphit\\u000a (1-[1-(3-isothiocyanatophenyl)-cyclohexyl]-piperidine)-induced audiogenic reflex epilepsy were studied. For the purpose of the study, valproate in the doses of 50 or 75 mg\\/kg and\\u000a DSIP (1.0 mg\\/kg) was i.p. injected either alone or in combination to adult Wistar male rats with fully developed metaphit\\u000a seizures after eight audiogenic

Olivera Stanojlovi?; Dragan Hrn?i?; Aleksandra Raši?; Helena Lon?ar-Stevanovi?; Dragan Djuric; Veselinka Šuši?

2007-01-01

24

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

PubMed

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

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

1989-08-01

25

On the Lipid Composition of Human Meibum and Tears: Comparative Analysis of Nonpolar Lipids  

PubMed Central

PURPOSE To qualitatively compare the nonpolar lipids present in meibomian gland (MG) secretions (samples T1) with aqueous tears (AT) collected from the lower tear menisci of healthy, non-dry eye volunteers using either glass microcapillaries (samples T2) or Schirmer test strips (samples T3). METHODS Samples T1 to T3 were analyzed with the use of high-pressure liquid chromatography/positive ion mode atmospheric pressure chemical ionization mass spectrometry. Where possible, the unknown lipids were compared with known standards. RESULTS Samples T1 had the simplest lipid composition among all the tested specimens. Samples T2 and T3 were similar to each other but were noticeably different from samples T1. In addition to all the compounds detected in samples T1, lower molecular weight wax esters and other compounds were found in samples T2 and T3. No appreciable amounts of fatty acid amides (e.g., oleamide), ceramides, or monoacyl glycerols were routinely detected. The occasionally observed minor signals of oleamide (m/z 282) in samples T3 were attributed to the contamination of the samples with common plasticizers routinely found in plastic ware extractives and organic solvents. CONCLUSIONS The MG is a prominent source of lipids for the tear film. However, it would have been a mistake to exclude from consideration other likely sources of lipids such as conjunctiva, cornea, and tears produced by the lacrimal glands. These data showed that lipids in AT are more complex than MG secretions, which necessitates more cautious interpretation of the functions of the latter in the tear film.

Butovich, Igor A.

2009-01-01

26

Fatty acid amide hydrolase in brain ventricular epithelium: mutually exclusive patterns of expression in mouse and rat  

Microsoft Academic Search

Fatty acid amides and fatty acid ethanolamides are novel signalling molecules exemplified by the sleep-inducing lipid oleamide and the endocannabinoid anandamide, respectively. These substances are inactivated by fatty acid amide hydrolase (FAAH), an enzyme that is expressed by neurons and non-neuronal cells in the brain. In the rat, FAAH-immunoreactivity has been detected in epithelial cells of the choroid plexus and,

Michaela Egertová; Gregory J. Michael; Benjamin F. Cravatt; Maurice R. Elphick

2004-01-01

27

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

PubMed

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

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

2014-09-01

28

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

2003-01-01

29

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

1998-01-01

30

Delta-Sleep-Inducing Peptide Potentiates Anticonvulsive Activity of Valproate against Metaphit-Provoked Audiogenic Seizure in Rats  

Microsoft Academic Search

The effect of delta-sleep-inducing peptide (DSIP) on the anticonvulsive activity of a nonprotective valproate (VPA) dose in a metaphit model of generalized, reflex audiogenic seizures in adult Wistar rats was studied. The animals that received metaphit (10 mg\\/kg) were exposed to audiogenic stimulation (100 ± 3 dB, 60 s) at hourly intervals. Metaphit-treated rats displaying seizures in 8 previous tests

2006-01-01

31

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

PubMed Central

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

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

2013-01-01

32

Vagotomy Attenuates Brain Cytokines and Sleep Induced by Peripherally Administered Tumor Necrosis Factor-? and Lipopolysaccharide in Mice  

PubMed Central

Study Objective: Systemic tumor necrosis factor-? (TNF-?) is linked to sleep and sleep altering pathologies in humans. Evidence from animals indicates that systemic and brain TNF-? have a role in regulating sleep. In animals, TNF-? or lipopolysaccharide (LPS) enhance brain pro-inflammatory cytokine expression and sleep after central or peripheral administration. Vagotomy blocks enhanced sleep induced by systemic TNF-? and LPS in rats, suggesting that vagal afferent stimulation by TNF-? enhances pro-inflammatory cytokines in sleep-related brain areas. However, the effects of systemic TNF-? on brain cytokine expression and mouse sleep remain unknown. Design: We investigated the role of vagal afferents on brain cytokines and sleep after systemically applied TNF-? or LPS in mice. Measurements and Results: Spontaneous sleep was similar in vagotomized and sham-operated controls. Vagotomy attenuated TNF-?- and LPS-enhanced non-rapid eye movement sleep (NREMS); these effects were more evident after lower doses of these substances. Vagotomy did not affect rapid eye movement sleep responses to these substances. NREMS electroencephalogram delta power (0.5-4 Hz range) was suppressed after peripheral TNF-? or LPS injections, although vagotomy did not affect these responses. Compared to sham-operated controls, vagotomy did not affect liver cytokines. However, vagotomy attenuated interleukin-1 beta (IL-1?) and TNF-? mRNA brain levels after TNF-?, but not after LPS, compared to the sham-operated controls. Conclusions: We conclude that vagal afferents mediate peripheral TNF-?-induced brain TNF-? and IL-1? mRNA expressions to affect sleep. We also conclude that vagal afferents alter sleep induced by peripheral pro-inflammatory stimuli in mice similar to those occurring in other species. Citation: Zielinski MR; Dunbrasky DL; Taishi P; Souza G; Krueger JM. Vagotomy attenuates brain cytokines and sleep induced by peripherally administered tumor necrosis factor-? and lipopolysaccharide in mice. SLEEP 2013;36(8):1227-1238.

Zielinski, Mark R.; Dunbrasky, Danielle L.; Taishi, Ping; Souza, Gianne; Krueger, James M.

2013-01-01

33

Effects of delta sleep-inducing peptide on pre- and postsynaptic glutamate and postsynaptic GABA receptors in neurons of the cortex, hippocampus, and cerebellum in rats.  

PubMed

We studied the effect of delta sleep-inducing peptide on GABA receptors of hippocampal and cerebellar neurons in rats. It was shown that delta sleep-inducing peptide considerably and dose-dependently potentiates GABA-activated currents in these neurons and blocks NMDA-activated potentiation in cortical and hippocampal neurons. The peptide modulates activity of presynaptic NMDA receptors, which is seen from changes in (45)Ca(2+) uptake into synaptosomes of the brain cortex after uptake stimulation with glutamate and NMDA. PMID:17369935

Grigor'ev, V V; Ivanova, T A; Kustova, E A; Petrova, L N; Serkova, T P; Bachurin, S O

2006-08-01

34

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

SciTech Connect

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

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

1986-01-01

35

Discovery of a Potent, Selective, and Efficacious Class of Reversible ?-Ketoheterocycle Inhibitors of Fatty Acid Amide Hydrolase Effective as Analgesicsa  

PubMed Central

Fatty acid amide hydrolase (FAAH) degrades neuromodulating fatty acid amides including anandamide (endogenous cannabinoid agonist) and oleamide (sleep-inducing lipid) at their sites of action and is intimately involved in their regulation. Herein we report the discovery of a potent, selective, and efficacious class of reversible FAAH inhibitors that produce analgesia in animal models validating a new therapeutic target for pain intervention. Key to the useful inhibitor discovery was the routine implementation of a proteomics-wide selectivity screen against all serine hydrolases ensuring selectivity for FAAH coupled with systematic in vivo examinations of candidate inhibitors.

Boger, Dale L.; Miyauchi, Hiroshi; Du, Wu; Hardouin, Christophe; Fecik, Robert A.; Cheng, Heng; Hwang, Inkyu; Hedrick, Michael P.; Leung, Donmienne; Acevedo, Orlando; Guimaraes, Cristiano R. W.; Jorgensen, William L.; Cravatt, Benjamin F.

2008-01-01

36

The structure of oleamide films at the aluminum/oil interface and aluminum/air interface studied by Sum Frequency Generation (SFG) vibrational spectroscopy and Reflection Absorption Infrared Spectroscopy (RAIRS).  

PubMed

The structure of oleamide (cis-9-octadecenamide) films on aluminum has been investigated by sum frequency generation vibrational spectroscopy (SFG) and reflection absorption infrared spectroscopy (RAIRS). Three different film deposition strategies were investigated: (i) films formed by equilibrium adsorption from oleamide solutions in oil, (ii) Langmuir-Blodgett films cast at 1 and 25 mN m(-1), (iii) thick spin-cast films. Both L-B and spin-cast films were examined in air and under oil. The adsorbate formed in the 1 mN m(-1) film in air showed little orientational order. For this film, the spectroscopic results and the ellipsometric thickness point to a relatively conformationally disordered monolayer that is oriented principally in the plane of the interface. Direct adsorption to the metal interface from oil results in SFG spectra of oleamide that are comparable to those observed for the 1 mN m(-1) L-B film in air. In contrast, SFG and RAIRS results for the 25 mN m(-1) film in air and SFG spectra of the spin-cast film in air both show strong conformational ordering and orientational alignment normal to the interface. The 25 mN m(-1) film has an ellipsometric thickness almost twice that of the 1 mN m(-1) L-B film. Taken in combination with the spectroscopic results, this is indicative of a well packed monolayer in air in which the hydrocarbon chain is in an essentially defect-free extended conformation with the methyl terminus oriented away from the surface. A similar structure is also deduced for the surface of the spin-cast film in air. Upon immersion of the 25 mN m(-1) L-B film in oil the SFG spectra show that this film rapidly adopts a relatively disordered structure similar to that seen for the 1 mN m(-1) L-B film in air. Immersion of the spin-cast film in oil results in the gradual disordering of the amide film over a period of several days until the observed spectra become essentially identical to those observed for direct adsorption of oleamide from oil. PMID:20355782

Casford, Michael T L; Davies, Paul B

2009-08-01

37

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

SciTech Connect

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

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

1987-07-01

38

Fatty acid amide hydrolase (-/-) mice exhibit an increased sensitivity to the disruptive effects of anandamide or oleamide in a working memory water maze task.  

PubMed

Although recent evidence suggests that fatty acid amide hydrolase (FAAH) may represent a potential therapeutic target, few published studies have investigated FAAH or its fatty acid amide substrates (FAAs) in animal models of learning and memory. Therefore, our primary goal was to determine whether FAAH (-/-) mice, which possess elevated levels of anandamide and other FAAs, would display altered performance in four Morris water maze tasks: acquisition of a hidden fixed platform, reversal learning, working memory, and probe trials. FAAH (-/-) mice failed to exhibit deficits in any task; in fact, they initially acquired the working memory task more rapidly than FAAH (+/+) mice. The second goal of this study was to investigate whether the FAAH inhibitor OL-135 (1-oxo-1[5-(2-pyridyl)-2-yl]-7-phenylheptane), anandamide, other FAAs, and methanandamide would affect working memory in both genotypes. FAAH (-/-), but not (+/+), mice displayed working memory impairments following exogenous administration of anandamide (ED(50) = 6 mg/kg) or oleamide (50 mg/kg). However, the central cannabinoid receptor (CB(1)) receptor antagonist SR141716 [N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide HCl] only blocked the disruptive effects of anandamide. Methanandamide, which is not metabolized by FAAH, disrupted working memory performance in both genotypes (ED(50) = 10 mg/kg), suggesting that CB(1) receptor signaling is unaltered by FAAH deletion. In contrast, OL-135 and other FAAs failed to affect working memory in either genotype. These results suggest that FAAH deletion does not impair spatial learning but may enhance acquisition under certain conditions. More generally, FAAH may represent a novel therapeutic target that circumvents the undesirable cognitive side effects commonly associated with direct-acting cannabinoid agonists. PMID:16352706

Varvel, Stephen A; Cravatt, Benjamin F; Engram, April E; Lichtman, Aron H

2006-04-01

39

Implication of tryptophan in the stimulatory effect of delta-sleep-inducing peptide on indole secretion from perifused rat pineal glands.  

PubMed

We have recently demonstrated that delta-sleep-inducing peptide (DSIP) stimulates indolamine secretion from rat pineal glands. In the present study, we show that tryptophan (TRP), as well as DSIP, stimulate melatonin (MEL) and 5-methoxy-tryptophol (5-ML) secretion in a dose-dependent manner between 5 x 10(-6) and 10(-4) M. The kinetic characteristics of the MEL and 5-ML secretion and the response induced by the two substances were similar. The increase in MEL secretion in response to 10(-4) M DSIP was completely inhibited by pretreatment of the pineals with 10(-5) M phenanthroline (amino-peptidase inhibitor), suggesting that stimulatory effect of DSIP was due to TRP liberated by peptide degradation. This mechanism occurring in the pineal was confirmed using 10(-4) M para-chlorophenylalamine (TRP hydroxylase inhibitor), which reduced the pineal response to 10(-4) and 10(-5) M DSIP by 50 and 100%, respectively. PMID:1307916

Ouichou, A; Pévet, P

1992-01-01

40

Oat lipids  

Microsoft Academic Search

Oats are a significant world crop. While nutritional interest in food oats has concentrated on oats as a source of dietary\\u000a fiber, the lipid component has both nutritional and technological potential. Thus, the lipid fraction of the oat grain determines\\u000a in large measure its energy content and has a significant impact on nutritional quality. The oat lipids mediate the pasting

Meixue Zhou; Kevin Robards; Malcolm Glennie-Holmes; Stuart Helliwell

1999-01-01

41

Bioactive amides of fatty acids.  

PubMed

Amides of fatty acids are lipid bioregulators formed from long chain saturated and unsaturated fatty acids via amidation by the corresponding amines. Ethanolamides of fatty acids are the most well-studied species of this group; an alternative pathway for their biosynthesis includes hydrolysis of N-acylated phosphatidylethanolamines by phospholipase D. Ethanolamides of fatty acids bind to the cannabinoid receptors of the central nervous system (CB1) or peripheral tissues (CB2) and can be considered as endogenous ligands of these receptors. Their pharmacological properties are similar to that of cannabimimetics. Simple amides of fatty acids are also endogenous bioregulators acting like sleep-inducing (oleamide) or angiogenic factors (erucamide). A new group of bioregulators comprise the amides of fatty acids and biologically active amines (vanillinamine, dopamine, and serotonin). PMID:9526091

Bezuglov, V V; Bobrov MYu; Archakov, A V

1998-01-01

42

Lipid Profile  

MedlinePLUS

... Necessity of Fasting Before Cholesterol and Other Lipid Tests (2013), More Youths Need Cholesterol Screening, says AAP (2011) Elsewhere On The Web Familydoctor.org: Heart Disease, Assessing Your Risk American ...

43

Fatty acid amide hydrolase in brain ventricular epithelium: mutually exclusive patterns of expression in mouse and rat.  

PubMed

Fatty acid amides and fatty acid ethanolamides are novel signalling molecules exemplified by the sleep-inducing lipid oleamide and the endocannabinoid anandamide, respectively. These substances are inactivated by fatty acid amide hydrolase (FAAH), an enzyme that is expressed by neurons and non-neuronal cells in the brain. In the rat, FAAH-immunoreactivity has been detected in epithelial cells of the choroid plexus and, in accordance with this finding, here we report FAAH mRNA expression in rat choroid plexus epithelium using in situ hybridisation methods. Surprisingly, a comparative analysis of mouse brain did not reveal FAAH mRNA expression or FAAH-immunoreactivity in the choroid plexus of this species. FAAH-immunoreactivity was, however, detected in non-choroidal ventricular ependymal cells in the mouse brain and the specificity of this immunostaining was confirmed by analysis of FAAH-knockout mice. FAAH-immunoreactivity was detected in ependymal cells throughout the ventricles of the mouse brain but with regional variation in the intensity of immunostaining. Intriguingly, in rat brain, although FAAH expression is observed in choroid plexus epithelial cells, little or no FAAH-immunoreactivity is present in the ventricular ependyma. Thus, there are mutually exclusive patterns of FAAH expression in the ventricular epithelium of rat and mouse brain. Our observations provide the basis for an experimental analysis that exploits differences in FAAH expression in rat and mouse to investigate FAAH function in ventricular epithelial cells and, in particular, the role of FAAH in regulating the sleep-inducing agent oleamide in cerebrospinal fluid. PMID:15482903

Egertová, Michaela; Michael, Gregory J; Cravatt, Benjamin F; Elphick, Maurice R

2004-11-01

44

Cycling lipids.  

PubMed

When synaptic vesicles fuse with the presynaptic plasma membrane, their membrane constituents are recycled by internalisation into clathrin-coated vesicles. To form new synaptic vesicles, the clathrin coat must be shed and recent studies reveal that a lipid phosphatase, synaptojanin, plays a central role in this process. PMID:10662657

Stenmark, H

2000-01-27

45

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

2007-01-01

46

Lipid antigens in immunity.  

PubMed

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

Dowds, C Marie; Kornell, Sabin-Christin; Blumberg, Richard S; Zeissig, Sebastian

2014-01-01

47

Lipid Storage Myopathy  

Microsoft Academic Search

Lipid storage myopathy (LSM) is pathologically characterized by prominent lipid accumulation in muscle fibers due to lipid\\u000a dysmetabolism. Although extensive molecular studies have been performed, there are only four types of genetically diagnosable\\u000a LSMs: primary carnitine deficiency (PCD), multiple acyl-coenzyme A dehydrogenase deficiency (MADD), neutral lipid storage\\u000a disease with ichthyosis, and neutral lipid storage disease with myopathy. Making an accurate

Wen-Chen Liang; Ichizo Nishino

2011-01-01

48

Lipase-catalysed ammoniolysis of lipids. A facile synthesis of fatty acid amides  

Microsoft Academic Search

Ammoniolysis of triglycerides to the corresponding fatty acid amides is efficiently catalysed byCandida antarctica lipase (Novozym 435). Thus, olive oil gave 90% of nearly pure oleamide after 72 h at 60°C. Jojoba wax was similarly converted into a mixture ofcis-11-eicosenamide and erucamide together withcis-11-eicosenol andcis-l3-docosenol.

M. C. de Zoete; A. C. Kock-van Dalen; F. van Rantwijk; R. A. Sheldon

1996-01-01

49

Lipase-catalysed ammoniolysis of lipids. A facile synthesis of fatty acid amides  

Microsoft Academic Search

Ammoniolysis of triglycerides to the corresponding fatty acid amides is efficiently catalysed by Candida antarctica lipase (Novozym 435). Thus, olive oil gave 90% of nearly pure oleamide after 72 h at 60 °C. Jojoba wax was similarly converted into a mixture of cis-11-eicosenamide and erucamide together with cis-11-eicosenol and cis-13-docosenol.

M. C. de Zoete; A. C. Kock-van Dalen; F. van Rantwijk; R. A. Sheldon

1996-01-01

50

Plant Lipid Rafts  

PubMed Central

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

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

2007-01-01

51

Vincristine Lipid Complex Injection  

MedlinePLUS

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

52

Daunorubicin Lipid Complex Injection  

MedlinePLUS

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

53

Autophagy regulates lipid metabolism  

PubMed Central

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 as an energy source. Lipolysis and autophagy share similarities in regulation and function but are not known to be interrelated. Here we show a previously unknown function for autophagy in regulating intracellular lipid stores (macrolipophagy). Lipid droplets and autophagic components associated during nutrient deprivation, and inhibition of autophagy in cultured hepatocytes and mouse liver increased triglyceride storage in lipid droplets. This study identifies a critical function for autophagy in lipid metabolism that could have important implications for human diseases with lipid over-accumulation such as those that comprise the metabolic syndrome.

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

2009-01-01

54

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

2008-01-01

55

Lipids and Prostate Cancer  

PubMed Central

The role of lipid metabolism has gained particular interest in prostate cancer research. A large body of literature has outlined the unique upregulation of de novo lipid synthesis in prostate cancer. Concordant with this lipogenic phenotype is a metabolic shift, in which cancer cells use alternative enzymes and pathways to facilitate the production of fatty acids. These newly synthesized lipids may support a number of cellular processes to promote cancer cell proliferation and survival. Hence, de novo lipogenesis is under intense investigation as a therapeutic target. Epidemiologic studies suggest dietary fat may also contribute to prostate cancer; however, whether dietary lipids and de novo synthesized lipids are differentially metabolized remains unclear. Here, we highlight the lipogenic nature of prostate cancer, especially the promotion of de novo lipid synthesis, and the significance of various dietary lipids in prostate cancer development and progression.

Suburu, Janel; Chen, Yong Q.

2012-01-01

56

Lipids in Plant Mitochondria  

Microsoft Academic Search

\\u000a Mitochondria perform a variety of fundamental functions and are of pivotal importance in plant physiology and development.\\u000a They possess a typical membrane lipid composition that is largely conserved in all eukaryotes. To establish and maintain their\\u000a lipid pattern, they have to cooperate with other organelles, where a significant portion of their lipids are produced and\\u000a subsequently assembled into the mitochondrial

Radin Sadre; Margrit Frentzen

57

[Lipids in Taenia saginata].  

PubMed

Lipids of Taenia saginata were analyzed by means of thin layer chromatography and gas liquid chromatography. Total lipids comprised about 3.3% of the fresh weight and consisted mainly of triglycerides (65.62%), sterols (19.58%), phospholipids (10.16%). The fatty acids of the triglycerides were mainly unsaturated and differed from those of phospholipids. The parasite has practically no "de novo" fatty acid biosynthesis, although this cestode did synthetize complex lipids from single lipids provided by the diet. PMID:973747

Cicchini, T; Belli, M; Messeri, E; Passi, S

1976-01-01

58

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.

2013-01-01

59

Lipid rich rhabdomyosarcoma  

Microsoft Academic Search

A lipid rich rhabdomyosarcoma of the paratesticular region was studied by light microscopy, histochemistry, immunohistochemistry and electron microscopy. The tumour was composed of primitive looking, vacuolated, and pleomorphic cells. Lipid was present in varying amounts in all cells but was especially abundant in the vacuolated and pleomorphic cells. Some cells showed eosinophilic fibrillary cytoplasm but cross-striations were not seen. Tumour

C Quincey; S S Banerjee; B P Eyden; K S Vasudev

1994-01-01

60

Lipids of Ziziphora pedicellata  

Microsoft Academic Search

The amounts and compositions of the lipids, pigments, and fatty acids in the inflorescences, leaves, and stems and the total air-dry biomass ofZiziphora pedicellata Pazij. et Vved. have been established. The essential oil content of the biomass has been determined. A similarity of the qualitative composition of the lipids and pigments, an increase in the amount of unsaponifiable substances, and

S. D. Gusakova; T. V. Khomova

1997-01-01

61

Lysosomal Lipid Storage Diseases  

PubMed Central

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.

Schulze, Heike; Sandhoff, Konrad

2011-01-01

62

Arachidonoylserotonin and Other Novel Inhibitors of Fatty Acid Amide Hydrolase  

Microsoft Academic Search

Fatty acid amide hydrolase (FAAH) catalyzes the hydrolysis of bioactive fatty acid amides and esters such as the endogenous cannabinoid receptor ligands, anandamide (N-arachidonoyl-ethanolamine) and 2-arachidonoylglycerol, and the putative sleep inducing factorcis-9-octadecenoamide (oleamide). Most FAAH blockers developed to date also inhibit cytosolic phospholipase A2(cPLA2) and\\/or bind to the CB1 cannabinoid receptor subtype. Here we report the finding of four novel

T. Bisogno; D. Melck; L. De Petrocellis; M. Yu. Bobrov; N. M. Gretskaya; V. V. Bezuglov; N. Sitachitta; W. H. Gerwick; V. Di Marzo

1998-01-01

63

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.

2012-01-01

64

Lipids of Debaryomyces hansenii  

PubMed Central

Merdinger, Emanuel (Roosevelt University, Chicago, Ill.), and Edward M. Devine, Jr. Lipids of Debaryomyces hansenii. J. Bacteriol. 89:1488–1493. 1965.—The separation of neutral lipids and phospholipids from the lipid extract of Debaryomyces hansenii NRRL Y-1448 was accomplished by using a single column packed with silicic acid. The neutral lipids comprised 67%, and the phospholipids 33%, of the total lipid extract. Qualitative and quantitative characterization of the lipids was effected by various analytical procedures. Gas chromatography of the fatty acid methyl esters showed 11 acids, of which 59.7% were unsaturated. The most abundant among the unsaturated acids was the monounsaturated C18 acid (50.1%). Among the saturated acids, palmitic acid (23.5%) prevailed. Ratios of fatty acid to glycerol, phosphorus to glycerol, and phosphorus to fatty acid were ascertained for combined cuts from the neutral lipids and the phospholipids. The presence of ergosterol, stigmasterol, and an unidentified sterol was established by gas chromatography. Also present were saturated hydrocarbons containing 16 to 39 carbon atoms, C22 being the most prevalent.

Merdinger, Emanuel; Devine, Edward M.

1965-01-01

65

Lipid-absorbing polymers  

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

66

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

1965-01-01

67

PHYSIOLOGY: Unfolding Lipid Metabolism  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required: A transcription factor exhibits dual roles, regulating genes that respond to improperly folded proteins and genes that control lipid synthesis.

Jay D. Horton (University of Texas Southwestern Medical Center at Dallas;Departments of Molecular Genetics and Internal Medicine)

2008-06-13

68

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.

1986-01-01

69

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

1996-01-01

70

Drugs affecting lipid synthesis  

Microsoft Academic Search

The apparent direct casual relationship of elevated blood lipids to the pathogenesis of atherosclerosis has resulted in many\\u000a lines of investigation directed toward the control of lipids, particularly cholesterol, in blood and tissues. Much of this\\u000a work during the past decade has been concerned with the regulation of endogenous synthesis of cholesterol. No attempt has\\u000a been made herein to discuss

W. L. Holmes; Smith Kline

1964-01-01

71

Focus Issue: Signaling Lipids  

NSDL National Science Digital Library

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

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

2006-02-07

72

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.

73

Lipids of subcellular particles  

Microsoft Academic Search

Methods for isolation and characterization of subcellular particles as well as procedures for analysis of lipid class composition\\u000a are discussed. The literature on distribution of lipids in subcellular particles is then reviewed. Pertinent new data from\\u000a our laboratories are presented as well. The isolated particles are related to the organelles to which they correspond in the\\u000a cell and are discussed

Sidney Fleischer; George Rouser

1965-01-01

74

Acyl-Lipid Metabolism  

PubMed Central

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

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

2013-01-01

75

Acyl-Lipid Metabolism  

PubMed Central

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

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

2010-01-01

76

Sebaceous gland lipids  

PubMed Central

The principal activity of mature sebaceous glands is producing and secreting sebum, which is a complex mixture of lipids. Sebum composition is different among species and this difference is probably due to the function that sebum has to absolve. In human sebum there are unique lipids, such as squalene and wax esters not found anywhere else in the body nor among the epidermal surface lipids. Moreover, they correspond to major components supplying the skin with protection. However, the ultimate role of human sebum, as well the metabolic pathways regulating its composition and secretion rate, are far from a complete understanding. Increased sebum secretion is considered, among all features, the major one involved in the pathophysiology of acne. Along with increased sebum secretion rate, quali- and quantitative modifications of sebum are likely to occur in this pathology. Understanding the factors and mechanisms that regulate sebum production is needed in order to identify new targets that can be addressed to achieve a selective modulation of lipid biosynthesis as a novel therapeutic strategy to correct lipid disregulations in acne and other disorders of the pilosebaceous unit.

Ottaviani, Monica; Camera, Emanuela; Mastrofrancesco, Arianna

2009-01-01

77

Discovery and molecular basis of potent noncovalent inhibitors of fatty acid amide hydrolase (FAAH)  

PubMed Central

Fatty acid amide hydrolase (FAAH), an amidase-signature family member, is an integral membrane enzyme that degrades lipid amides including the endogenous cannabinoid anandamide and the sleep-inducing molecule oleamide. Both genetic knock out and pharmacological administration of FAAH inhibitors in rodent models result in analgesic, anxiolytic, and antiinflammatory phenotypes. Targeting FAAH activity, therefore, presents a promising new therapeutic strategy for the treatment of pain and other neurological-related or inflammatory disorders. Nearly all FAAH inhibitors known to date attain their binding potency through a reversible or irreversible covalent modification of the nucleophile Ser241 in the unusual Ser-Ser-Lys catalytic triad. Here, we report the discovery and mechanism of action of a series of ketobenzimidazoles as unique and potent noncovalent FAAH inhibitors. Compound 2, a representative of these ketobenzimidazoles, was designed from a series of ureas that were identified from high-throughput screening. While urea compound 1 is characterized as an irreversible covalent inhibitor, the cocrystal structure of FAAH complexed with compound 2 reveals that these ketobenzimidazoles, though containing a carbonyl moiety, do not covalently modify Ser241. These inhibitors achieve potent inhibition of FAAH activity primarily from shape complementarity to the active site and through numerous hydrophobic interactions. These noncovalent compounds exhibit excellent selectivity and good pharmacokinetic properties. The discovery of this distinctive class of inhibitors opens a new avenue for modulating FAAH activity through nonmechanism-based inhibition.

Min, Xiaoshan; Thibault, Stephen T.; Porter, Amy C.; Gustin, Darin J.; Carlson, Timothy J.; Xu, Haoda; Lindstrom, Michelle; Xu, Guifen; Uyeda, Craig; Ma, Zhihua; Li, Yihong; Kayser, Frank; Walker, Nigel P. C.; Wang, Zhulun

2011-01-01

78

Monoolein: a magic lipid?  

PubMed

During the last few years, there has been an extraordinary increase in publications describing the manifold applications of monoolein, one of the most important lipids in the fields of drug delivery, emulsion stabilization and protein crystallization. In this perspective we present a comprehensive review of the phase behavior of this 'magic lipid'. An account of various mesophases formed in the presence of water and a collection of formulae for the calculation of their nano-structural parameters are provided. Effects of chemical and biological molecules including lipids, detergents, salts, sugars, proteins and DNA on the classical behavior are also discussed. Physicochemical triggers such as, temperature, pressure and shearing modulate the phase behavior of monoolein self assemblies that are covered in subsequent sections. Finally the growing applications of monoolein in various fields are also reported. PMID:21183976

Kulkarni, Chandrashekhar V; Wachter, Wolfgang; Iglesias-Salto, Guillermo; Engelskirchen, Sandra; Ahualli, Silvia

2011-02-28

79

Immobilized lipid-bilayer materials  

DOEpatents

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)

2000-01-01

80

Lipid microencapsulation in starch.  

PubMed

Short microwave heating of granular potato, waxy corn and tapioca starches with such lipids as cis-9-octadecenoic acid (oleic acid), cis,cis-9,12-octadecadienoic acid (linoleic acid), octadecanoic acid (stearic acid), ethyl cis-9-octadecenoate, ethyl cis,cis-9,12-octadecadienoate and methyl octadecanoate provided microcapsules in which encapsulated guest molecules did not interact with starch microcapsules. On the formation of microcapsules, the lipid guest molecules did not react to starches. The encapsulation yield varied between almost 11-94%. PMID:16801245

Kapu?niak, J; Tomasik, P

2006-05-01

81

Lipid Microdomains in Cell Nucleus  

PubMed Central

It is known that nuclear lipids play a role in proliferation, differentiation, and apoptotic process. Cellular nuclei contain high levels of phosphatidylcholine and sphingomyelin, which are partially linked with cholesterol and proteins to form lipid–protein complexes. These lipids are also associated with transcription factors and newly synthesized RNA but, up to date, their organization is still unknown. The aim of the present work was to study if these specific lipid–protein interactions could be nuclear membrane microdomains and to evaluate their possible role. The results obtained demonstrate for the first time the existence of nuclear microdomains characterized by a specific lipid composition similar to that of intranuclear lipid–protein complexes previously described. Nuclear microdomain lipid composition changes during cell proliferation when the content of newly synthesized RNA increases. Because previous data show a correlation between nuclear lipids and transcription process, the role of nuclear microdomains in cellular functions is discussed.

Cascianelli, Giacomo; Villani, Maristella; Tosti, Marcello; Marini, Francesca; Bartoccini, Elisa; Viola Magni, Mariapia

2008-01-01

82

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

2001-02-01

83

Structure of lipid bilayers  

PubMed Central

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

Nagle, John F.; Tristram-Nagle, Stephanie

2009-01-01

84

Structure of lipid bilayers.  

PubMed

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

Nagle, J F; Tristram-Nagle, S

2000-11-10

85

No hypothermic response to serotonin in 5HT7 receptor knockout mice  

Microsoft Academic Search

With data from recently available selective antagonists for the 5-HT7 receptor, it has been hypothesized that 5-hydroxytryptamine (5-HT)-induced hypothermia is mediated by the 5-HT7 receptor, an effect previously attributed to other receptor subtypes. It has been established that the biologically active lipid oleamide allosterically interacts with the 5-HT7 receptor to regulate its transmission. The most well characterized effects of oleamide

P. B. Hedlund; P. E. Danielson; E. A. Thomas; K. Slanina; M. J. Carson; J. G. Sutcliffe

2003-01-01

86

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

2000-01-01

87

Lysosomal degradation of membrane lipids.  

PubMed

The constitutive degradation of membrane components takes place in the acidic compartments of a cell, the endosomes and lysosomes. Sites of lipid degradation are intralysosomal membranes that are formed in endosomes, where the lipid composition is adjusted for degradation. Cholesterol is sorted out of the inner membranes, their content in bis(monoacylglycero)phosphate increases, and, most likely, sphingomyelin is degraded to ceramide. Together with endosomal and lysosomal lipid-binding proteins, the Niemann-Pick disease, type C2-protein, the GM2-activator, and the saposins sap-A, -B, -C, and -D, a suitable membrane lipid composition is required for degradation of complex lipids by hydrolytic enzymes. PMID:19836391

Kolter, Thomas; Sandhoff, Konrad

2010-05-01

88

Lipids in vascular function  

Microsoft Academic Search

Physiological and pathological vascular responses depend on the action of numerous intercellular mediators, ranging from hormones\\u000a to gases like nitric oxide, proteins, and lipids. The last group consists not only of the different types of lipoproteins,\\u000a but also includes a broad array of other lipophilic signaling molecules such as fatty acids, eicosanoids, phospholipids and\\u000a their derivatives, sphingolipids and isoprenoids. Due

Alois Sellmayer; Nina Hrboticky; Peter C. Weber

1999-01-01

89

Painted supported lipid membranes  

PubMed Central

We report herein measurements on a novel type of supported lipid films, which we call painted supported membranes (PSM). These membranes are formed in a self-assembly process on alkylated gold films from an organic solution. The formation process was investigated with surface plasmon resonance microscopy. The optical and electrical properties of the films were determined for various types of lipids and as a function of temperature by means of cyclic voltammetry and potential relaxation after charge injection. We could show that these films exhibit an extraordinarily high specific resistivity which, depending on the lipid, may be as high as 109 ohm/cm2. We could also show that due to this low conductivity, an electrical polarization across the PSM relaxes with characteristic time constants of up to 20 min. The electrical properties together with their high mechanical stability and accessibility to surface sensitive techniques make these films well suitable model membranes for optical and electrical investigations. Examples for such applications are given in the subsequent article by Seifert et al. ImagesFIGURE 3FIGURE 4

Florin, E.-L.; Gaub, H. E.

1993-01-01

90

Lipid chain packing and lipid-protein interaction in membranes  

NASA Astrophysics Data System (ADS)

This article describes briefly several applications of a molecular theory of lipid organization in membranes to systems of biophysical interest. After introducing the basic concepts of this mean field theory we outline three of its recent applications. i) Calculations of lipid chain conformational statistics in membrane bilayers, and comparison of the results (e.g. bond orientational order parameters) to experiment and molecular dynamics simulations. Good agreement is found. ii) A molecular model for lipid-protein interactions, which explicitly considers the effects of a rigid hydrophobic protein on the elastic (conformational) properties of the lipid bilayer. We also analyze the role of the ‘hydrophobic mismatch’ between the protein and lipid bilayer thickness. iii) A molecular level calculation of the vesicle to micelle transition, attendant upon the addition of (‘curvature loving’) surfactant to a lipid bilayer vesicle. Future applications, e.g. to the calculation of the free energy barriers involved in membrane fusion are briefly mentioned.

Fattal, Deborah R.; Ben-Shaul, Avinoam

1995-02-01

91

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

2011-01-01

92

RF Microalgal lipid content characterization  

PubMed Central

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

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

2014-01-01

93

RF Microalgal lipid content characterization.  

PubMed

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

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

2014-01-01

94

Lipids of Rosa canina pericarp  

Microsoft Academic Search

Pericarp of air-dried fruit were separated from seeds. The yield was 56.0% of the fruit mass, moisture 14.4%. Total lipids were extracted from the previously ground raw material by CHCl 3 with MeOH (2:1). The yield was 5.5% of the fruit mass. The extract was washed to remove non-lipid components (0.05%) using aqueous CaCl 2 . The total lipid mass

N. T. Ul’chenko; N. P. Bekker; O. A. Aripov; A. I. Glushenkova

2009-01-01

95

Hypertension and lipids.  

PubMed

Hypertension and hyperlipidaemia are closely interrelated. Both belong to the most important risk factors of cardiovascular disease, with special emphasis on the premature development of atherosclerosis and its complications. The prevalence of both hypertension and hyperlidaemia is high; in the Polish adult population, like in many other countries, it amounts to 20-40% and 60-70%, respectively. The prevalence of hyperlipidaemia in patients with essential hypertension is much higher than in the normotensive subjects and both abnormalities markedly increase the risk of cardiovascular disease. In so called Familial Dyslipidaemic Hypertension, the 16 years mortality rates were 4 times higher than in subjects with dyslipidaemia and hypertension as single risk factors. The present data point to essential hypertension as a metabolic disorder, which may have some pathogenetic links with the derangement of lipid metabolism. According to the recent results, only about 15% of all hypertensives do not exhibit metabolic disturbances. One of the most important topics in this respect is the influence of antihypertensive drugs on metabolic factors, with special reference to lipid metabolism. Some of these drugs may have unfavourable action on lipid variables, while other are neutral or even beneficial. These differences may have great impact on the therapeutic approach to hypertensive patients and form the basis for the concept of individualized therapy of hypertension. The goal of antihypertensive therapy is not only to lower the blood pressure but also to influence all other factors which may be significant for the prognosis. Only such an integrated approach may prevent atherosclerotic complications and reduce the risk of cardiovascular morbidity and mortality. PMID:9162431

Sznajderman, M

1996-01-01

96

Lipid biology of breast cancer.  

PubMed

Alterations in lipid metabolism have been reported in many types of cancer. Lipids have been implicated in the regulation of proliferation, differentiation, apoptosis, inflammation, autophagy, motility and membrane homeostasis. It is required that their biosynthesis is tightly regulated to ensure homeostasis and to prevent unnecessary energy expenditure. This review focuses on the emerging understanding of the role of lipids and lipogenic pathway regulation in breast cancer, including parallels drawn from the study of metabolic disease models, and suggestions on how these findings can potentially be exploited to promote gains in HER2/neu-positive breast cancer research. This article is part of a Special Issue entitled Lipid Metabolism in Cancer. PMID:23562840

Baumann, Jan; Sevinsky, Christopher; Conklin, Douglas S

2013-10-01

97

Lipid-lowering agents.  

PubMed

The role of lipid lowering in reducing the risk of mortality and morbidity from cardiovascular disease (CVD) is well established. Treatment particularly aimed at decreasing low-density lipoprotein cholesterol (LDL-C) is effective in reducing the risk of death from coronary heart disease and stroke. Statins form the cornerstone of treatment. However, in some individuals with a high risk of CVD who are unable to achieve their target LDL-C due to either intolerance or lack of efficacy, there is the need for alternative therapies. This review provides an overview of the different classes of currently available lipid-lowering medications including statins, fibrates, bile acid sequestrants (resins), and omega-3 fatty acids. Data are presented on their indications, pharmacology, and the relevant end point clinical trial data with these drugs. It also discusses the human trial data on some novel therapeutic agents that are being developed including those for homozygous familial hypercholesterolemia--the antisense oligonucleotide mipomersen and the microsomal transfer protein inhibitor lomitapide. Data are presented on phase II and III trials on agents with potentially wider applications, cholesterol ester transfer protein inhibitors and proprotein convertase subtilisin kexin 9 inhibitors. The data on a licensed gene therapy for lipoprotein lipase deficiency are also presented. PMID:23811423

Ewang-Emukowhate, Mfon; Wierzbicki, Anthony S

2013-09-01

98

[Adipokines and lipids].  

PubMed

Insulin resistance, hyperleptinaemia and low plasma levels of adiponectin are also widely related to features of the MS. The functional capacity of the adipose tissue varies among subjects explaining the incomplete overlapping among the metabolic syndrome and obesity. Far turnover is determined by a complex equilibrium in which insulin is a main factor but not the only one. Chronically inadequate energy balance may be a key factor, stressing the system. In this situation, an adipose tissue functional failure occurs resulting in changes in systemic energy delivery, impaired glucose consumption and activation of self-regulatory mechanisms that extend their influence to the whole body homeostasis system. Lipid metabolism alterations in liver and peripheral tissues are addressed, with particular reference to adipose and muscle tissues, and the mechanisms by which some adipokines, namely leptin and adiponectin, mediate the regulation of fatty acid oxidation in those tissues. The activation of the AMPK (AMP-dependent kinase) pathway, together with a subsequent increase in the fatty acid oxidation, appear to constitute the main mechanism of action of these hormones in the regulation of lipid metabolism. A decreased activation of AMPK appears to have a role in the development of features of the MS. In addition, the alteration of AMPK signalling in the hypothalamus, which may function as a sensor of nutrient availability, integrating multiple nutritional and hormonal signals, may have a key role in the appearance of the MS. PMID:19702116

Sumarac-Dumanovi?, Mirjana; Jeremi?, Danka

2009-01-01

99

Analysis of caulobacter crescentus lipids.  

PubMed Central

The lipids of Caulobacter crescentus, a procaryotic species which differentiates into stalked and swarmer cell types, were analyzed. Major lipid classes were purified by chromatography and identified by both chromatographic and chemical methods. Approximately half of the total lipid fraction of this organism consisted of glycolipis, which were primarily monoglucosyldiglyceride and an acylated glucuronic acid. Two of the phospholipids of C. crescentus were identified as phopshatidylglycerol and acylphosphatidylglycerol. Commonly occurring bacterial phospholipids, such as phosphatidylethanolamine and cardiolipin (diphosphatidylglycerol), were not detected. Monoglyceride and diglyceride were found in the neutral lipid fraction, which made up 10% of the total lipid. Quantitative lipid compositional studies, performed by the incorporation of [14C]acetate and [32P]orthophosphate into growing cultures, revealed that separated swarmer and stalked cells had similar lipid compositions. However, stationary-phase cultures, compared with logaritmic cultures, had decreased amounts of phosphatidylglycerol and diglyceride and increased amounts of acylphosphatidylglycerol and a glucuronic acid-containing glycolipid, glycolipid X. In addition, two glycolipids were only detected in stationary-phase cultures. These studies indicate that C. crescentus has a distinctive lipid composition compared with those of other procaryotic species which have been analyzed. Images

De Siervo, A J; Homola, A D

1980-01-01

100

Lipids in critical care medicine  

Microsoft Academic Search

While enteral nutrition is the basis for the critically ill, parenteral nutrition is often used when a sufficient enteral nutrition is not or not fully achievable. Lipids are a mainstay of caloric supply in both cases as they combine the provision of building blocks for the membranes and are precursors for function molecules including lipid mediators bearing the ability to

Juliane Ott; Christopher Hiesgen; Konstantin Mayer

2011-01-01

101

Dynamics of Lipids in Synthetic Membranes.  

National Technical Information Service (NTIS)

Bilayer coliposomes were created from blends of head-group functionalized and non-functionalized synthetic lipids. Functionalized lipids in the outer leaflets of the bilayers were then chemically differentiated from the (unchanged) functionalized lipids o...

R. A. Moss

1994-01-01

102

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

2007-01-01

103

Lipid Mediators in Acne  

PubMed Central

Multiple factors are involved in acne pathogenesis, and sebum secretion is one of the main ones. The role sebum plays in acne development has not been completely elucidated yet; however, increasing amounts of data seem to confirm the presence of alterations in sebum from acne patients. Altered ratio between saturated and unsaturated fatty acids has been indicated as an important feature to be considered in addition to the altered amount of specific fatty acids such as linoleic acid. Furthermore, particular attention has been focused on squalene peroxide that seems to be able to induce an inflammatory response beyond cytotoxicity and comedones formation. Moreover, recent data suggest that lipid mediators are able to interfere with sebocytes differentiation and sebogenesis through the activation of pathways related to peroxisome proliferators-activated receptors. Understanding the factors and mechanisms that regulate sebum production is needed in order to identify novel therapeutic strategies for acne treatment.

Ottaviani, Monica; Camera, Emanuela; Picardo, Mauro

2010-01-01

104

Association of lipid metabolism with ovarian cancer  

PubMed Central

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

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

2010-01-01

105

Mitochondrial lipid transport at a glance.  

PubMed

Lipids are the building blocks of cellular membranes and are synthesized at distinct parts of the cell. A precise control of lipid synthesis and distribution is crucial for cell function and survival. The endoplasmic reticulum (ER) is the major lipid-synthesizing organelle. However, a subset of lipids is synthesized within mitochondria, and this aspect has become a focus of recent lipid research. Mitochondria form a dynamic membrane network that is reshaped by fusion and fission events. Their functionality therefore depends on a continuous lipid supply from the ER and the distribution of lipids between both mitochondrial membranes. The mechanisms of mitochondrial lipid trafficking are only now emerging and appear to involve membrane contact sites and lipid transfer proteins. In this Cell Science at a Glance article, we will discuss recent discoveries in the field of mitochondrial lipid trafficking that build on long-standing observations and shed new light on the shuttling of membrane lipids between mitochondria and other organelles. PMID:24190879

Scharwey, Melanie; Tatsuta, Takashi; Langer, Thomas

2013-12-01

106

Lipid acquisition by intracellular Chlamydiae.  

PubMed

Chlamydia species are obligate intracellular pathogens that are important causes of human genital tract, ocular and respiratory infections. The bacteria replicate within a specialized membrane-bound compartment termed the inclusion and require host-derived lipids for intracellular growth and development. Emerging evidence indicates that Chlamydia has evolved clever strategies to fulfil its lipid needs by interacting with multiple host cell compartments and redirecting trafficking pathways to its intracellular niche. In this review, we highlight recent findings that have significantly expanded our understanding of how Chlamydia exploit lipid trafficking pathways to ensure the survival of this important human pathogen. PMID:22452394

Elwell, Cherilyn A; Engel, Joanne N

2012-07-01

107

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

1987-01-01

108

Membrane lipid segregation in endocytosis  

NASA Astrophysics Data System (ADS)

We explore the equilibrium mechanics of a binary lipid membrane that wraps around a spherical or cylindrical particle. One of the lipid membrane components induces a positive spontaneous curvature, while the other induces a negative local curvature. Using a Hamiltonian approach, we derive the equations governing the membrane shape and lipid concentrations near the wrapped object. Asymptotic expressions and numerical solutions for membrane shapes are presented. We determine the regimes of bending rigidity, surface tension, intrinsic lipid curvature, and effective receptor binding energies that lead to efficient wrapping and endocytosis. Our model is directly applicable to the study of invagination of clathrin-coated pits and receptor-induced wrapping of colloids such as spherical virus particles.

Nowak, Sarah A.; Chou, Tom

2008-08-01

109

Microrheology of freestanding lipid bilayers  

NASA Astrophysics Data System (ADS)

The macroscopic material properties of cellular membranes, determined by the composition and interactions of their constituent lipids, are important factors in the structure and function of all living cells. Fluidity is a key material property of membranes, yet the underlying lipid bilayer viscosity and other rheological parameters remain poorly quantified. We adopt recently developed microrheological methods to study multiple composite freestanding ``black'' lipid membranes. Using high speed video particle tracking, we monitor dynamics of membrane-anchored nano- and micro-particles across a range of temperatures that span bilayer phase transitions. Two particle spatial correlation functions and the complex shear modulus are extracted from such measurements and provide information about fundamental membrane material properties. We find striking and previously unreported signatures of viscoelasticity in these lipid bilayers whose properties are sensitive to the bilayers' temperature dependent liquid ordered to liquid disordered phase transitions.

Harland, Christopher; Bradley, Miranda; Parthasarathy, Raghuveer

2010-03-01

110

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

2011-01-01

111

Other Cannabimimetic Lipid Signaling Molecules  

Microsoft Academic Search

The endogenous lipids anandamide and 2-arachidonoylglycerol (2-AG) play predominant signaling roles through G protein-coupled\\u000a receptors (GPCRs) and at least one transient receptor potential channel (TRP). Additional structurally similar lipid signaling\\u000a molecules that have cannabinoid-like (cannabimimetic) activity in which they produce similar cellular, physiological, and\\u000a behavioral phenotypes as anandamide and 2-AG have recently been discovered. Like the endogenous cannabinoids, many of

Heather B. Bradshaw

112

[Lipids of Aureobasidium (Pullularia) pullulans].  

PubMed

Fractional composition of free and bound lipids was studied in Aureobasidium (Pullularia) pullulans 8 by preparative TLC on Silufol. Bound lipids contained a fraction (27.76 +/- 0.5%) of dark brown colour, similar to melanin. The composition of fatty acids was studied by GLC. The following fatty acids were identified and determined quantitatively: C12:0, C14:0, C15:0, C16:0, C18:0, C18:1+C15:2. The following fatty acids predominated in free and bound lipids: C16:0, C18:1+C18:2. The ratio between unsaturated and saturated fatty acids in all fractions of free and bound lipids was more than unity. The following parameters were determined for lipids; ester number (173.89 and 178.53); iodine number (44.1 and 33.10), and saponification number (181.17 and 206.03) (the values are given for free and bound lipids, respectively). PMID:1240572

Elinov, N P; Iurlova, N A; Efimova, T P

1975-01-01

113

Lipid bilayers on nano-templates  

DOEpatents

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

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

2009-08-04

114

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

1988-01-01

115

Mass Spectrometry Methodology in Lipid Analysis  

PubMed Central

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

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

2014-01-01

116

Yeast lipid metabolism at a glance.  

PubMed

During the last decades, lipids have gained much attention due to their involvement in health and disease. Lipids are required for the formation of membranes and contribute to many different processes such as cell signaling, energy supply, and cell death. Various organelles such as the endoplasmic reticulum, mitochondria, peroxisomes, and lipid droplets are involved in lipid metabolism. The yeast Saccharomyces cerevisiae has become a reliable model organism to study biochemistry, molecular biology, and cell biology of lipids. The availability of mutants bearing defects in lipid metabolic pathways and the ease of manipulation by culture conditions facilitated these investigations. Here, we summarize the current knowledge about lipid metabolism in yeast. We grouped this large topic into three sections dealing with (1) fatty acids; (2) membrane lipids; and (3) storage lipids. Fatty acids serve as building blocks for the synthesis of membrane lipids (phospholipids, sphingolipids) and storage lipids (triacylglycerols, steryl esters). Phospholipids, sterols, and sphingolipids are essential components of cellular membranes. Recent investigations addressing lipid synthesis, degradation, and storage as well as regulatory aspects are presented. The role of enzymes governing important steps of the different lipid metabolic pathways is described. Finally, the link between lipid metabolic and dynamic processes is discussed. PMID:24520995

Klug, Lisa; Daum, Günther

2014-05-01

117

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

PubMed

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 gamma-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 gamma-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 ((1)H-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 (1)H-NMR, whereby the crystallinity of the lipid nanoparticles diminishes with an increase in the liquid lipid content. For the distribution of gamma-oryzanol inside the lipid nanoparticles, the (1)H-NMR revealed that the chemical shifts of the liquid lipid in gamma-oryzanol loaded systems were found at rather higher field than those in gamma-oryzanol free systems, suggesting incorporation of gamma-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 gamma-oryzanol in the liquid part rather than the solid part of in the lipid nanoparticles. Simple models representing the distribution of gamma-oryzanol and lipids (solid and liquid) inside the lipid nanoparticle systems are proposed. PMID:20182010

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

2010-03-26

118

LIPIDS OF SARCINA LUTEA II.  

PubMed Central

Albro, Phillip W. (Ft. Detrick, Frederick, Md.), and Charles K. Huston. Lipids of Sarcina lutea. II. Hydrocarbon content of the lipid extracts. J. Bacteriol. 88:981–986. 1964.—The hydrocarbon fraction from Sarcina lutea lipid extracts was characterized by a combination of thin-layer and gas-liquid chromatography and infrared spectroscopy. A total of 37 components were observed by gas-liquid chromatography of this material. A breakdown of the components into classes indicated a composition consisting of 88.9% n-saturates, 1.2% monoenes, 2.1% dienes, 5.0% trienes, and 0.6% branched-saturates. Less than 0.1% of the hydrocarbon material was aromatic. No attempt was made in this study to relate the composition to either origin or function in the cell.

Albro, Phillip W.; Huston, Charles K.

1964-01-01

119

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

2011-01-01

120

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

PubMed

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

2012-07-17

121

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

122

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)

2007-03-01

123

Lipids of Sarcina lutea III. Composition of the Complex Lipids  

PubMed Central

Huston, Charles K. (Fort Detrick, Frederick, Md.), Phillip W. Albro, and Gerald B. Grindey. Lipids of Sarcina lutea. III. Composition of the complex lipids. J. Bacteriol. 89:768–775. 1965.—The complex lipids from a strain of Sarcina lutea were isolated and separated into fractions on diethylaminoethyl cellulose acetate and silicic acid columns. These fractions were monitored in several thin-layer chromatography systems. The various lipid types were characterized by their behavior in thin-layer systems and by an analysis of their hydrolysis products. The fatty acid composition of the column fractions was determined by gas-liquid chromatography. A number of components (13) were separated by thin-layer chromatography and characterized. The major components were polyglycerol phosphatide (17.0%), lipoamino acids (15.1%), phosphatidyl glycerol (13.8%), and an incompletely characterized substance (15.0%). Minor constituents included phosphatidyl inositol (5.5%), phosphatidic acid (4.2%), phosphatidyl serine (2.0%), and phosphatidyl choline (1.0%). No phosphatidyl ethanolamine was observed.

Huston, Charles K.; Albro, Phillip W.; Grindey, Gerald B.

1965-01-01

124

Mast cells: from lipid droplets to lipid mediators  

PubMed Central

LDs (lipid droplets) are metabolically highly active intracellular organelles. The lipid and protein profiles of LDs are cell-type-specific, and they undergo dynamic variation upon changes in the physiological state of a cell. It is well known that the main function of the LDs in adipocytes is to ensure energy supply and to maintain lipid homoeostasis in the body. In contrast, LDs in inflammatory cells have been implicated in eicosanoid biosynthesis, particularly under inflammatory conditions, thereby enabling them to regulate immune responses. Human mast cells are potent effector cells of the innate immune system, and the triacylglycerol (triglyceride) stores of their cytoplasmic LDs have been shown to contain large amounts of arachidonic acid, the main precursor of pro-inflammatory eicosanoids. In the present review, we discuss the current knowledge about the formation and function of LDs in inflammatory cells with specific emphasis on arachidonic acid and eicosanoid metabolism. On the basis of findings reported previously and our new observations, we propose a model in which lipolysis of LD-triacylglycerols provides arachidonic acid for lipid mediator generation in human mast cells.

Dichlberger, Andrea; Kovanen, Petri T.; Schneider, Wolfgang J.

2013-01-01

125

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

2010-01-01

126

Lipids of Candida Utilis: Changes with Growth.  

National Technical Information Service (NTIS)

Total lipids were extracted from cells of Candida utilis grown in batch, chemostat, and phased culture. Thin-layer chromatography of the extracts showed qualitative changes in the different lipid classes with growth. Gas-liquid chromatography was used to ...

P. S. S. Dawson B. M. Craig

1965-01-01

127

Methods and Compositions to Inhibit Lipid Oxidation.  

National Technical Information Service (NTIS)

The invention relates to methods and compositions for the inhibition of lipid oxidation in food products susceptible to lipid oxidation. The invention provides natural lipophilic antioxidant compositions extracted from fruit used for use in a variety of p...

M. P. Richards C. H. Lee J. D. Reed

2004-01-01

128

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

2004-01-01

129

Patterning Lipid Bilayers on Microfabricated Metal Electrodes.  

National Technical Information Service (NTIS)

Lipid molecules were immobilized on surface of photolithographically patterned chromium and titanium. Large unilamellar lipid vesicles were found to bind on the native oxide surface of patterned support metals. Metal evaporation and resist liftoff techniq...

R. N. Orth I. Hafez J. Kmeoka M. Lindau H. G. Craighead

2001-01-01

130

Viscoelastic properties of edible lipids  

Microsoft Academic Search

The viscoelastic natures of beeswax, candelilla wax, carnauba wax and a high-melting milkfat fraction were compared by estimating their relaxation parameters from stress relaxation data. A generalized Maxwell model consisting of one spring element and two Maxwell elements best described the stress relaxation of all lipids tested. The stress responses over both the compressive and relaxation portions of a stress

T. H. Shellhammer; T. R. Rumsey; J. M. Krochta

1997-01-01

131

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)

2004-12-01

132

Evolution of lipid management guidelines  

PubMed Central

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

John Bosomworth, N.

2014-01-01

133

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

134

21 CFR 862.1470 - Lipid (total) test system.  

... A lipid (total) test system is a device intended to measure total lipids (fats or fat-like substances) in serum and plasma. Lipid (total) measurements are used in the diagnosis and treatment of various diseases involving lipid metabolism and...

2014-04-01

135

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

2004-01-01

136

Electron Microscopic Studies of Lipid Protein Films  

Microsoft Academic Search

PROTEINS can be adsorbed from the solution on lipid mono-layers at the air water interface. One may expect that a lipid protein film is formed consisting of a closely packed layer of protein molecules attached to the hydrophilic side of the lipid film. The quantity of protein adsorbed can be evaluated by measuring the optical extinction, but this value is

Peter Fromherz

1971-01-01

137

Stability of protein-decorated mixed lipid membranes: The interplay of lipid-lipid, lipid-protein, and protein-protein interactions  

Microsoft Academic Search

Membrane-associated proteins are likely to contribute to the regulation of the phase behavior of mixed lipid membranes. To gain insight into the underlying mechanism, we study a thermodynamic model for the stability of a protein-decorated binary lipid layer. Here, proteins interact preferentially with one lipid species and thus locally sequester that species. We aim to specify conditions that lead to

Stephan Loew; Anne Hinderliter; Sylvio May

2009-01-01

138

Photoconversion of bodipy-labeled lipid analogues.  

PubMed

MOVING COLORS: Bodipy-labeled lipid analogues can change their photophysical properties and/or localization in the membrane upon light illumination. These changes are highly influenced by the lipid environment. This phenomenon can lead to lipid-environment-specific false positive signals in experimental techniques where spectral identity/separation is important. PMID:23512865

Sezgin, Erdinc; Chwastek, Grzegorz; Aydogan, Gokcan; Levental, Ilya; Simons, Kai; Schwille, Petra

2013-04-15

139

Integral hair lipid in human hair follicle  

Microsoft Academic Search

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

Won-Soo Lee

2011-01-01

140

Seasonal Variations of Serum Lipids and Apoproteins  

Microsoft Academic Search

Seasonal variations of blood lipids, which must be considered when performing long-term studies, could be partially due to dietary changes. In the present study, serum lipid parameters were measured each month for 1 year in nuns living in a monastery, whose diet was perfectly regular and controlled. The serum lipid variations observed consisted mainly of an increase in total cholesterol,

J. C. Buxtorf; M. F. Baudet; C. Martin; J. L. Richard; B. Jacotot

1988-01-01

141

NMR lipid profiles of cells, tissues, and body fluids: proton NMR analysis of human erythrocyte lipids.  

PubMed

One- and two-dimensional high resolution NMR spectroscopy was applied to determine quantitatively and qualitatively the lipids extracted from human erythrocyte membranes. The relative amounts of the major lipids were determined from the spectra of unfractionated lipid extracts. After HPLC fractionation of the lipid extracts and NMR analysis of the fractions, it was possible to determine the features of the component lipids of each lipid class and to compare, especially, the fatty acid types and composition of the individual major glycerophospholipids. The results of this proton NMR analysis were compared to those obtained elsewhere using classical lipid analytical techniques and found to be in substantial agreement. PMID:7868971

Adosraku, R K; Choi, G T; Constantinou-Kokotos, V; Anderson, M M; Gibbons, W A

1994-11-01

142

Sleep induced by stimulation in the human pedunculopontine nucleus area.  

PubMed

The pedunculopontine nucleus is part of the reticular ascending arousal system and is involved in locomotion and sleep. Two patients with Parkinson disease received electrodes that stimulated the pedunculopontine nucleus area to alleviate their severe gait impairment. Instead, we found that low-frequency stimulation of the pedunculopontine nucleus area increased alertness, whereas high-frequency stimulation induced non-rapid eye movement sleep. In addition, the sudden withdrawal of the low-frequency stimulation was consistently followed by rapid eye movement sleep episodes in 1 patient. These data have the potential to benefit patients who suffer from sleep disorders. PMID:20437591

Arnulf, Isabelle; Ferraye, Muriel; Fraix, Valérie; Benabid, Alim Louis; Chabardès, Stephan; Goetz, Laurent; Pollak, Pierre; Debû, Bettina

2010-04-01

143

Molecular mechanism of sleep induced by prostaglandin D 2  

Microsoft Academic Search

Prostaglandin (PG) D2 is recognized as the most potent endogenous sleep-promoting substance whose mechanism of action is the best characterized among the various potential sleep substances thus far reported. Lipocalin-type PGD synthase is dominantly produced in the arachnoid membrane and choroid plexus of the brain, and is secreted into the cerebrospinal fluid to become ?-trace, a major protein in human

Yoshihiro Urade

2002-01-01

144

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

2001-03-01

145

Lipid domains in HIV-1 assembly  

PubMed Central

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

Yandrapalli, Naresh; Muriaux, Delphine; Favard, Cyril

2014-01-01

146

Emerging targets in lipid-based therapy?  

PubMed Central

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.

Tucker, Stephanie C.; Honn, Kenneth V.

2013-01-01

147

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

1999-01-01

148

Lipid Polymorphisms and Membrane Shape  

PubMed Central

Morphological plasticity of biological membrane is critical for cellular life, as cells need to quickly rearrange their membranes. Yet, these rearrangements are constrained in two ways. First, membrane transformations may not lead to undesirable mixing of, or leakage from, the participating cellular compartments. Second, membrane systems should be metastable at large length scales, ensuring the correct function of the particular organelle and its turnover during cellular division. Lipids, through their ability to exist with many shapes (polymorphism), provide an adequate construction material for cellular membranes. They can self-assemble into shells that are very flexible, albeit hardly stretchable, which allows for their far-reaching morphological and topological behaviors. In this article, we will discuss the importance of lipid polymorphisms in the shaping of membranes and its role in controlling cellular membrane morphology.

Frolov, Vadim A.; Shnyrova, Anna V.; Zimmerberg, Joshua

2011-01-01

149

Lipid Bodies in Inflammatory Cells  

PubMed Central

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

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

2011-01-01

150

[Blood lipids in renal amyloidosis].  

PubMed

Serum lipids were estimated in patients with renal amyloidosis (RA): 21 with familial Mediterranean fever (FMF) and 24 with secondary renal amyloidosis versus FMF patients without renal dysfunction or having chronic glomerular nephritis. All the RA patients had dyslipidemia of atherogenic nature the severity of which correlated with that of renal disorder. Our results showed the presence of dyslipidemia early during RA course. It is renal involvement that results in dyslipidemia observed in FMF patients. PMID:7941122

Srinivas, K V; Neverov, N I; Kolonduk, N V; Tambovtseva, E V; Kozlova, R I

1993-01-01

151

PHOTOLYTIC LIPIDS FROM VISUAL PIGMENTS  

PubMed Central

A method is described for the preservation of iodopsin, the labile photopigment of daylight vision, by freeze drying in vacuo. The lipids released by the action of light on rhodopsin and iodopsin are found to be similar and to possess a labile absorption spectrum in chloroform, with a rising peak at about 390 mµ and a declining peak in the region of 470 mµ. After the change is complete the absorption spectrum resembles closely that of retinene.

Bliss, Alfred Frederick

1946-01-01

152

Isolation and analysis of membrane lipids and lipid rafts in common carp (Cyprinus carpio L.).  

PubMed

Cell membranes act as an interface between the interior of the cell and the exterior environment and facilitate a range of essential functions including cell signalling, cell structure, nutrient uptake and protection. It is composed of a lipid bilayer with integrated proteins, and the inner leaflet of the lipid bilayer comprises of liquid ordered (Lo) and liquid disordered (Ld) domains. Lo microdomains, also named as lipid rafts are enriched in cholesterol, sphingomyelin and certain types of proteins, which facilitate cell signalling and nutrient uptake. Lipid rafts have been extensively researched in mammals and the presence of functional lipid rafts was recently demonstrated in goldfish, but there is currently very little knowledge about their composition and function in fish. Therefore a protocol was established for the analysis of lipid rafts and membranous lipids in common carp (Cyprinus carpio L.) tissues. Twelve lipids were identified and analysed in the Ld domain of the membrane with the most predominant lipids found in all tissues being; triglycerides, cholesterol, phosphoethanolamine and phosphatidylcholine. Four lipids were identified in lipid rafts in all tissues analysed, triglycerides (33-62%) always found in the highest concentration followed by cholesterol (24-32%), phosphatidylcholine and sphingomyelin. Isolation of lipid rafts was confirmed by identifying the presence of the lipid raft associated protein flotillin, present at higher concentrations in the detergent resistant fraction. The data provided here build a lipid library of important carp tissues as a baseline for further studies into virus entry, protein trafficking or environmental stress analysis. PMID:24326265

Brogden, Graham; Propsting, Marcus; Adamek, Mikolaj; Naim, Hassan Y; Steinhagen, Dieter

2014-03-01

153

Lipid transport by mammalian ABC proteins.  

PubMed

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

Quazi, Faraz; Molday, Robert S

2011-09-01

154

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

PubMed

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

2011-04-27

155

Sphingolipids in lipid microdomains and obesity.  

PubMed

Sphingolipids are major constituents of the plasma membrane, where they are known to form lipid microdomains with cholesterol. Lipid microdomains are thought to be important not only for cellular signal transduction but also for the absorption of extracellular lipids or nutrients. Inhibition of sphingolipid biosynthesis suggested an importance for sphingolipids in fatty acid uptake via lipid microdomains. Additionally, we recently reported that the function of lipid microdomains was dynamically regulated by the sphingomyelin synthase SMS2 on the plasma membrane and that SMS2-deficient mice exhibit resistance against high-fat diet-induced increases in body weight, glucose intolerance, and fatty liver. Now, biosynthesis or metabolism of sphingolipids is thought to be involved in obesity, diabetes, and cardiovascular diseases. In this review, I focus on the functions of sphingolipids in lipid microdomains and describe their contributions to obesity and diabetes. PMID:23374721

Mitsutake, Susumu; Igarashi, Yasuyuki

2013-01-01

156

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.

2010-01-01

157

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)

2010-01-18

158

Molecular Determinants of Milk Lipid Secretion  

Microsoft Academic Search

Mammary epithelial cells secrete lipids by an envelopment process that produces lipid droplets coated by membranes derived\\u000a from the plasma membrane and possibly secretory vesicles. This secretion process, which resembles viral budding, is hypothesized\\u000a to be mediated by specific interactions between molecules on the surface of intracellular lipids and membrane elements of\\u000a the cell. Multiple lines of evidence indicate that

James L. McManaman; Tanya D. Russell; Jerome Schaack; David J. Orlicky; Horst Robenek

2007-01-01

159

Compartmentalization of proteins in lipid droplet biogenesis.  

PubMed

Our existing understanding of the structure, protein organization and biogenesis of the lipid droplet has relied heavily on microscopical techniques that lack resolution and the ability to preserve native cellular and protein composition. The electron microscopic technique of freeze-fracture replica immunogold labeling (FRIL) overcomes these problems, and is currently providing new perspectives in the field. Because of the property of frozen lipids to deflect the fracture plane, en face views of the lipid droplet and its component layers are revealed for high resolution visualization. By means of immunogold labeling, proteins involved in the accretion and mobilization of lipids, notably the PAT family proteins, can be localized at and in the droplet. Application of this approach demonstrates that, contrary to prevailing wisdom, the PAT family proteins are not invariably restricted to the surface of the lipid droplet but can occur throughout the core. The notion that lipid droplet biogenesis involves neutral lipid accumulation within the ER membrane bilayer followed by budding off, enclosed by a protein-containing phospholipid monolayer, is not substantiated. Instead, lipid droplets appear to develop externally to both ER membranes at specialized sites in which the ER enwraps the droplet, and the facing leaflets of the ER membrane and droplet surface are enriched in adipophilin. PAT family proteins are not, as often stated, specific to the lipid droplet, but are widely present in the plasma membrane where, under conditions of lipid loading, they adopt a similar configuration to that of specialized sites in the ER. FRIL has further provided new insights into the mechanism of secretion of a special type of lipid droplet, the milk fat globule. These examples highlight the contribution of the FRIL technique to critical appraisal and development of concepts in the lipid droplet field. PMID:19118639

Robenek, Horst; Buers, Insa; Hofnagel, Oliver; Robenek, Mirko J; Troyer, David; Severs, Nicholas J

2009-06-01

160

Polar lipid composition of a new halobacterium  

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

161

Identification and composition of turnip root lipids  

Microsoft Academic Search

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

Marius Lepage

1967-01-01

162

Lipids as organizers of cell membranes  

PubMed Central

The 105th Boehringer Ingelheim Fonds International Titisee Conference ‘Lipids as Organizers of Cell Membranes' took place in March 2012, in Germany. Kai Simons and Gisou Van der Goot gathered cell biologists and biophysicists to discuss the interplay between lipids and proteins in biological membranes, with an emphasis on how technological advances could help fill the gap in our understanding of the lipid part of the membrane.

Kornmann, Benoit; Roux, Aurelien

2012-01-01

163

Pore formation phase diagrams for lipid membranes  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

164

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

1999-01-01

165

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

PubMed Central

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

Vogedes, Daniel; Varpe, ?ystein; S?reide, Janne E.; Graeve, Martin; Berge, J?rgen; Falk-Petersen, Stig

2010-01-01

166

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

1965-01-01

167

Brillouin scattering of lipid membranes  

NASA Astrophysics Data System (ADS)

The lamellar phases of lipids undergo several structural phase transitions, between a two dimensional crystalline packing and the fluid-like state [1]. High frequency elastic properties of oriented multilamellar dimyristoyl-phosphatidylcholine (DMPC) were investigated by means of Brillouin scattering. It turns out that the hypersound velocities are highly sensitive to the structural changes due to the lamellar phase transitions. The obvious structural anisotropy of the membrane stacks results in fact in a rather small elastic anisotropy as seen by the Brillouin measurements. The results are interpreted in terms of a simple effective medium model for regularly layered composite.

Manglkammer, W.; Krüger, J. K.

2005-10-01

168

Cholesterol Perturbs Lipid Bilayers Nonuniversally  

SciTech Connect

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

Pan Jianjun; Mills, Thalia T.; Tristram-Nagle, Stephanie; Nagle, John F. [Physics Department, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

2008-05-16

169

Phosphoinositides alter lipid bilayer properties  

PubMed Central

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

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

2013-01-01

170

Advances in Intravenous Lipid Emulsions  

Microsoft Academic Search

Over the past decade, our views have\\u000a considerably evolved with respect to the metabolism of intravenous\\u000a lipid emulsions and their composition. Substantial progress has been\\u000a made in understanding the metabolic pathways of emulsion particles and\\u000a the delivery of their various components (fatty acids and vitamins) to\\u000a specific tissues or cells. Although soybean long-chain triglycerides\\u000a represent a valuable source of energy,

2000-01-01

171

Electrodiffusion of lipids on membrane surfaces.  

PubMed

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

2012-05-28

172

Dictyostelium Lipid Droplets Host Novel Proteins  

PubMed Central

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.

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

2013-01-01

173

Air stability of supported lipid membrane spots  

NASA Astrophysics Data System (ADS)

Air-stability of supported lipid membranes is crucial to large scale applications of lipid membrane based biosensors and microarrays. Here we examined the air-stability of supported lipid membrane spots, and found that it was dependent on spot size. The smaller the lipid spot is, the more resistant to deterioration caused by air exposure it is, probably due to increased stable edge of small bilayer spots. This study suggests a strategy to design air-stable biomembrane based biosensors for biosensing applications.

Fang, Ye

2011-08-01

174

Roles of lipid metabolism in keloid development  

PubMed Central

Keloids are common cutaneous pathological scars that are characterised by the histological accumulation of fibroblasts, collagen fibres, and clinically significant invasive growth. Although increasing lines of research on keloids have revealed genetic and environmental factors that contribute to their formation, the etiology of these scars remains unclear. Several studies have suggested the involvement of lipid metabolism, from a nutritional point of view. However, the role that lipid metabolism plays in the pathogenesis and progression of keloids has not previously been reviewed. The progress that has been made in understanding the roles of the pro- and anti-inflammatory lipid mediators in inflammation, and how they relate to the formation and progression of keloids, is also outlined. In particular, the possible relationships between mechanotransduction and lipid metabolites in keloids are explored. Mechanotransduction is the process by which physical forces are converted into biochemical signals that are then integrated into cellular responses. It is possible that lipid rafts and caveolae provide the location of lipid signaling and interactions between these signaling pathways and mechanotransduction. Moreover, interactions between lipid signaling pathway molecules and mechanotransduction molecules have been observed. A better understanding of the lipid profile changes and the functional roles lipid metabolism plays in keloids will help to identify target molecules for the development of novel interventions that can prevent, reduce, or even reverse pathological scar formation and/or progression.

2013-01-01

175

Enhancement of non-polar lipid transfer reaction through stabilization of substrate lipid particles with apolipoproteins.  

PubMed

Transfer of lipids was studied between human plasma low density lipoproteins (LDL) and triolein particles coated with an egg phosphatidylcholine monolayer, with diameter of 27 +/- 4 nm. The lipid particles were unstable and seemed to aggregate to LDL when incubated with LDL either in the presence or the absence of bovine serum albumin. Human apolipoproteins A-I, A-II, C-II, C-III, and E stabilized the lipid particles and completely prevented this process. Cholesterol rapidly appeared in the lipid particles to reach homogeneous distribution among the phospholipid surfaces of LDL and the lipid particles regardless of whether apolipoproteins were present or absent. Cholesteryl ester spontaneously appeared in the lipid particles to some extent in the absence of the apolipoproteins, and human plasma lipid transfer protein enhanced this reaction only to a very limited extend. When the lipid particles were stabilized with the apolipoproteins, spontaneous cholesteryl ester transfer was minimized and the lipid transfer protein catalyzed the transfer of cholesteryl ester markedly. There was no specific difference among the apolipoproteins in stabilizing the particles and enhancing the transfer reaction. Reciprocal decrease in volume of triglyceride was observed at the same time in the lipid particles until the relative content of cholesteryl ester in the cores of LDL was the same as in the lipid particles. The kinetics of the cholesteryl ester and triglyceride transfer was consistent with the model that the reaction is bidirectional in equilibrium and takes both non-polar lipids as substrate in a single pool. PMID:3360759

Nishikawa, O; Yokoyama, S; Okabe, H; Yamamoto, A

1988-01-01

176

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

PubMed Central

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

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

2012-01-01

177

Rapid microfluidic perfusion enabling kinetic studies of lipid ion channels in a bilayer lipid membrane chip.  

PubMed

There is growing recognition that lipids play key roles in ion channel physiology, both through the dynamic formation and dissolution of lipid ion channels and by indirect regulation of protein ion channels. Because existing technologies cannot rapidly modulate the local (bio)chemical conditions at artificial bilayer lipid membranes used in ion channel studies, the ability to elucidate the dynamics of these lipid-lipid and lipid-protein interactions has been limited. Here we demonstrate a microfluidic system supporting exceptionally rapid perfusion of reagents to an on-chip bilayer lipid membrane, enabling the responses of lipid ion channels to dynamic changes in membrane boundary conditions to be probed. The thermoplastic microfluidic system allows initial perfusion of reagents to the membrane in less than 1 s, and enables kinetic behaviors with time constants below 10 s to be directly measured. Application of the platform is demonstrated toward kinetic studies of ceramide, a biologically important lipid known to self-assemble into transmembrane ion channels, in response to dynamic treatments of small ions (La(3+)) and proteins (Bcl-x(L) mutant). The results reveal the broader potential of the technology for studies of membrane biophysics, including lipid ion channel dynamics, lipid-protein interactions, and the regulation of protein ion channels by lipid micro domains. PMID:21556947

Shao, Chenren; Sun, Bing; Colombini, Marco; Devoe, Don L

2011-08-01

178

Electroporation of heterogeneous lipid membranes.  

PubMed

Electroporation is the basis for the transfection of genetic material and for drug delivery to cells, including electrochemotherapy for cancer. By means of molecular dynamics many aspects of membrane electroporation have been unveiled at the molecular detail in simple, homogeneous, lipid bilayers. However, the correspondence of these findings \\with the process happening in cell membranes requires, at least, the consideration of laterally structured membranes. Here, I present a systematic molecular dynamics study of bilayers composed of different liquid-ordered and liquid-disordered lipid phases subjected to a transversal electric field. The simulations reveal two significant results. First, the electric field mainly affects the properties of the disordered phases, so that electroporation takes place in these membrane regions. Second, the smaller the disordered domains are, the faster they become electroporated. These findings may have a relevant significance in the experimental application of cell electroporation in vivo since it implies that electro-induced and pore-mediated transport processes occur in particularly small disordered domains of the plasma membrane, thus locally affecting only specific regions of the cell. PMID:24144543

Reigada, Ramon

2014-03-01

179

Lipid shedding from single oscillating microbubbles.  

PubMed

Lipid-coated microbubbles are used clinically as contrast agents for ultrasound imaging and are being developed for a variety of therapeutic applications. The lipid encapsulation and shedding of the lipids by acoustic driving of the microbubble has a crucial role in microbubble stability and in ultrasound-triggered drug delivery; however, little is known about the dynamics of lipid shedding under ultrasound excitation. Here we describe a study that optically characterized the lipid shedding behavior of individual microbubbles on a time scale of nanoseconds to microseconds. A single ultrasound burst of 20 to 1000 cycles, with a frequency of 1 MHz and an acoustic pressure varying from 50 to 425 kPa, was applied. In the first step, high-speed fluorescence imaging was performed at 150,000 frames per second to capture the instantaneous dynamics of lipid shedding. Lipid detachment was observed within the first few cycles of ultrasound. Subsequently, the detached lipids were transported by the surrounding flow field, either parallel to the focal plane (in-plane shedding) or in a trajectory perpendicular to the focal plane (out-of-plane shedding). In the second step, the onset of lipid shedding was studied as a function of the acoustic driving parameters, for example, pressure, number of cycles, bubble size and oscillation amplitude. The latter was recorded with an ultrafast framing camera running at 10 million frames per second. A threshold for lipid shedding under ultrasound excitation was found for a relative bubble oscillation amplitude >30%. Lipid shedding was found to be reproducible, indicating that the shedding event can be controlled. PMID:24798388

Luan, Ying; Lajoinie, Guillaume; Gelderblom, Erik; Skachkov, Ilya; van der Steen, Antonius F W; Vos, Hendrik J; Versluis, Michel; De Jong, Nico

2014-08-01

180

Efficient conversion of biomass into lipids by using the simultaneous saccharification and enhanced lipid production process  

PubMed Central

Background Microbial lipid production by using lignocellulosic biomass as the feedstock holds a great promise for biodiesel production and biorefinery. This usually involves hydrolysis of biomass into sugar-rich hydrolysates, which are then used by oleaginous microorganisms as the carbon and energy sources to produce lipids. However, the costs of microbial lipids remain prohibitively high for commercialization. More efficient and integrated processes are pivotal for better techno-economics of microbial lipid technology. Results Here we describe the simultaneous saccharification and enhanced lipid production (SSELP) process that is highly advantageous in terms of converting cellulosic materials into lipids, as it integrates cellulose biomass hydrolysis and lipid biosynthesis. Specifically, Cryptococcus curvatus cells prepared in a nutrient-rich medium were inoculated at high dosage for lipid production in biomass suspension in the presence of hydrolytic enzymes without auxiliary nutrients. When cellulose was loaded at 32.3 g/L, cellulose conversion, cell mass, lipid content and lipid coefficient reached 98.5%, 12.4 g/L, 59.9% and 204 mg/g, respectively. Lipid yields of the SSELP process were higher than those obtained by using the conventional process where cellulose was hydrolyzed separately. When ionic liquid pretreated corn stover was used, both cellulose and hemicellulose were consumed simultaneously. No xylose was accumulated over time, indicating that glucose effect was circumvented. The lipid yield reached 112 mg/g regenerated corn stover. This process could be performed without sterilization because of the absence of auxiliary nutrients for bacterial contamination. Conclusions The SSELP process facilitates direct conversion of both cellulose and hemicellulose of lignocellulosic materials into microbial lipids. It greatly reduces time and capital costs while improves lipid coefficient. Optimization of the SSELP process at different levels should further improve the efficiency of microbial lipid technology, which in turn, promote the biotechnological production of fatty acid-derived products from lignocellulosic biomass.

2013-01-01

181

Angptl3 regulates lipid metabolism in mice  

Microsoft Academic Search

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

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

2002-01-01

182

Archaeal lipids and their biotechnological applications  

Microsoft Academic Search

The lipids of Archaea, based on glycerol isopranoid ethers, can be used taxonomically to distinguish between phenotypic subgroups of the domain to delineate them clearly from all other organisms. This review is a general survey of the structural features of archaeal lipids and how they relate to survival in the harsh environments in which the Archaea live. The molecular organization

A. Gambacorta; A. Gliozzi; M. De Rosa

1995-01-01

183

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

2004-01-01

184

Lipid extraction from isolated single nerve cells  

NASA Technical Reports Server (NTRS)

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

Krasnov, I. V.

1977-01-01

185

Lipid Disorders in Renal Transplant Recipients  

Microsoft Academic Search

Plasma cholesterol, triglyceride, lipoprotein and phospholipid levels were higher in 76 transplant recipients than in normal age-matched controls. 22 patients exhibited a normal lipid pattern; 12 a type IIa, 12 a type lib, and 30 a type IV hyperlipidemia. Lipid abnormalities were not related to serum creatinine, parathyroid hormone (PTH), serum albumin, plasma glucose, transplant age, relative body weight or

C. Ponticelli; G. L. Barbi; A. Cantaluppi; A. De Vecchi; G. Annoni; C. Donati; M. Cecchettin

1978-01-01

186

Lipid rafts: contentious only from simplistic standpoints  

Microsoft Academic Search

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

John F. Hancock

2006-01-01

187

Quantitative metabolic profiling of lipid mediators.  

PubMed

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

2013-08-01

188

Digestion and Absorption of Lipids in Poultry  

Microsoft Academic Search

Ingested lipids undergo intestinal emunification, digestion, micellar sol111 iiIi\\/at iiin. cell membrane permeation, intracellular esterification and incorpora tion into lipoproteins before release to the interstitial fluid. Bile salts secretion, essen tial to both emulsification and micelle formation in the intestine, has been found to be influenced by quantity and quality of dietary lipids and by other emulsifiers. Modifications of dietary

à SHILD KROGDAHL

189

Immune modulation by parenteral lipid emulsions  

Microsoft Academic Search

Total parenteral nutrition is the final option for nutritional support of patients with severe intestinal failure. Lipid emulsions constitute the main source of fuel calories and fatty acids (FAs) in parenteral nutrition formulations. However, adverse effects on patient outcomes have been attributed to the use of lipids, mostly in relation to impaired immune defenses and altered inflammatory responses. Over the

G. J. A. Wanten; P. C. Calder

2007-01-01

190

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

2002-01-01

191

Sub-wavelength infrared imaging of lipids  

PubMed Central

Infrared absorption spectroscopy of lipid layers was performed by combining optics and scanning probe microscopy. This experimental approach enables sub-diffraction IR imaging with a spatial resolution on the nanometer scale of 1, 2-dioleoyl-sn-glycero-3-phosphocholine lipid layers.

Yarrow, Fiona; Kennedy, Eamonn; Salaun, Frederic

2011-01-01

192

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...

2010-04-01

193

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...

2009-04-01

194

Method of fabricating lipid bilayer membranes on solid supports  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

195

?-Synuclein Senses Lipid Packing Defects and Induces Lateral Expansion of Lipids Leading to Membrane Remodeling*  

PubMed Central

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.

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

2013-01-01

196

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

PubMed

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

2013-07-19

197

Lipid bilayer membrane arrays: fabrication and applications.  

PubMed

The lipid bilayer is one of the most important self-assembled structures in nature. In addition to compartmentalizing the cell, the lipid bilayer maintains many physical and biological characteristics of cell membranes, including lateral fluidity. It provides a wealth of opportunities for the study of membrane properties. Recently there has been an increasing interest in lipid bilayer arrays fabrication and their applications. In this review, the leading methods for creating lipid bilayer arrays are categorized as mechanical methods, pre-patterning substrate, direct UV patterning, direct blotting or stamping, polymer lift off technique, robotic micro spotting, and microfluidics. The applications of bilayer arrays for cell adhesion and activation, lipid bilayer based 2D electrophoresis, and high-throughput binding assays are also presented. PMID:22743692

Han, Xiaojun; Qi, Guodong; Xu, Xingtao; Wang, Lei

2013-01-01

198

The need to revisit lipid areas  

NASA Astrophysics Data System (ADS)

We have studied the structural properties of lipid bilayers made up of monounsaturated phosphatidylcholines (i.e. diCn:1PC, where n=14, 16, 18, 20, 22 and 24). High-resolution x-ray scattering data were analyzed in conjunction with contrast varied neutron scattering data, using the recently developed technique by Ku?erka et al. [Biophys. J. 95, 2356 (2008)]. Analyses of the data show that with increasing n lipid bilayers do not thicken in a linear fashion, as is often assumed, but quadratically, and that lipid area assumes a maximum value for n~18 bilayers. More importantly, compared to previous data our results strongly suggest that lipid areas are smaller by about 10%. This observation highlights the need to revisit lipid areas as they are extensively used in molecular dynamics simulations and for calibrating their force fields.

Ku?erka, N.; Gallová, J.; Uhríková, D.; Balgavý, P.; Katsaras, J.

2010-11-01

199

Lipid compartmentalization in the endosome system.  

PubMed

Lipids play an essential role in the structure of the endosomal membranes as well as in their dynamic rearrangement during the transport of internalized cargoes along the endocytic pathway. In this review, we discuss the function of endosomal lipids mainly in mammalian cells, focusing on two well-known components of the lipid rafts, sphingomyelin and cholesterol, as well as on three anionic phospholipids, phosphatidylserine, polyphosphoinositides and the atypical phospholipid, bis(monoacylglycero)phosphate/lysobisphosphatidic acid. We detail the structure, metabolism, distribution and role of these lipids in the endosome system as well as their importance in pathological conditions where modification of the endosomal membrane flow can lead to various diseases such as lipid-storage diseases, myopathies and neuropathies. PMID:24747366

Hullin-Matsuda, Françoise; Taguchi, Tomohiko; Greimel, Peter; Kobayashi, Toshihide

2014-07-01

200

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

2009-01-01

201

Lipid microarrays identify key mediators of autoimmune brain inflammation  

Microsoft Academic Search

Recent studies suggest that increased T-cell and autoantibody reactivity to lipids may be present in the autoimmune demyelinating disease multiple sclerosis. To perform large-scale multiplex analysis of antibody responses to lipids in multiple sclerosis, we developed microarrays composed of lipids present in the myelin sheath, including ganglioside, sulfatide, cerebroside, sphingomyelin and total brain lipid fractions. Lipid-array analysis showed lipid-specific antibodies

Jennifer L Kanter; Sirisha Narayana; Peggy P Ho; Ingrid Catz; Kenneth G Warren; Raymond A Sobel; Lawrence Steinman; William H Robinson

2005-01-01

202

Organismal Carbohydrate and Lipid Homeostasis  

PubMed Central

All living organisms maintain a high ATP:ADP ratio to drive energy-requiring processes. They therefore need mechanisms to maintain energy balance at the cellular level. In addition, multicellular eukaryotes have assigned the task of storing energy to specialized cells such as adipocytes, and therefore also need a means of intercellular communication to signal the needs of individual tissues and to maintain overall energy balance at the whole body level. Such signaling allows animals to survive periods of fasting or starvation when food is not available and is mainly achieved by hormonal and nervous communication. Insulin, adipokines, epinephrine, and other agonists thus stimulate pathways that regulate the activities of key enzymes involved in control of metabolism to integrate organismal carbohydrate and lipid metabolism. Overnutrition can dysregulate these pathways and have damaging consequences, causing insulin resistance and type 2 diabetes.

Hardie, D. Grahame

2012-01-01

203

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

1988-01-01

204

Structural elucidation of oxygenated storage lipids in cucumber cotyledons. Implication of lipid body lipoxygenase in lipid mobilization during germination.  

PubMed

At early stages of germination, a special lipoxygenase is expressed in cotyledons of cucumber and several other plants. This enzyme is localized at the lipid storage organelles and oxygenates their storage triacylglycerols. We have isolated this lipid body lipoxygenase from cucumber seedlings and found that it is capable of oxygenating in vitro di- and trilinolein to the corresponding mono-, di-, and trihydroperoxy derivatives. To investigate the in vivo activity of this enzyme during germination, lipid bodies were isolated from cucumber seedlings at different stages of germination, and the triacylglycerols were analyzed for oxygenated derivatives by a combination of high pressure liquid chromatography, gas chromatography/mass spectrometry, and nuclear magnetic resonance spectroscopy. We identified as major oxygenation products triacylglycerols that contained one, two, or three 13S-hydroperoxy-9(Z),11(E)-octadecadienoic acid residues. During germination, the amount of oxygenated lipids increased strongly, reaching a maximum after 72 h and declining afterward. The highly specific pattern of hydroperoxy lipids formed suggested the involvement of the lipid body lipoxygenase in their biosynthesis. These data suggest that this lipoxygenase may play an important role during the germination process of cucumber and other plants and support our previous hypothesis that the specific oxygenation of the storage lipids may initiate their mobilization as a carbon and energy source for the growing seedling. PMID:9261186

Feussner, I; Balkenhohl, T J; Porzel, A; Kühn, H; Wasternack, C

1997-08-22

205

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.

2009-01-01

206

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

PubMed

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

Tristram-Nagle, Stephanie; Nagle, John F

2004-01-01

207

The membrane lipids of Halobacterium halobium  

PubMed Central

The lipid content of the cell membrane of Halobacterium halobium increased from about 15% to 21% during exponential growth of the organism. Total lipid phosphorus more than doubled during the growth cycle. The mixture of membrane lipids from stationary-phase organisms was similar to lipid mixtures from whole cells of other halobacteria inasmuch as 80% of the lipid phosphorus occurred in a diether analogue of phosphatidylglycerophosphate and an additional 7·5% occurred in the ether analogue of phosphatidylglycerol. The lipid mixture was more complex than those reported for other halophils, however, 12 components being recognized in the acetone-insoluble fraction and 17 in the acetone-soluble fraction. There were major changes in the proportions of some minor components of the acetone-insoluble fraction during a growth cycle. Three nitrogenous lipids were recognized in the acetone-insoluble fraction, but all were present in relatively low proportion. One, which was not a phospholipid, contained a bound peptide. Of the 17 acetonesoluble compounds, 15 were pigments. The major carotenoids were ?- and ?-bacteriorubrin. The carotenoid pigments occurred at maximal concentration after 6–7 days' growth. ImagesFig. 2.

Marshall, Carolyn L.; Brown, A. D.

1968-01-01

208

LipidHome: A Database of Theoretical Lipids Optimized for High Throughput Mass Spectrometry Lipidomics  

PubMed Central

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

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

2013-01-01

209

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

PubMed

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

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

2013-01-01

210

Lipid body biogenesis and the role of microtubules in lipid synthesis in Ornithogalum umbellatum lipotubuloids.  

PubMed

Lipid bodies present in lipotubuloids of Ornithogalum umbellatum ovary epidermis take the form of a lens between leaflets of ER (endoplasmic reticulum) membrane filled with a highly osmiophilic substance. The two enzymes, DGAT1 [DAG (diacylglycerol) acyltransferase 1] and DGAT2 (DAG acyltransferase 2), involved in this process are synthesized on rough ER and localized in the ER near a monolayer surrounding entities like lipid bodies. After reaching the appropriate size, newly formed lipid bodies transform into mature spherical lipid bodies filled with less osmiophilic content. They appear to be surrounded by a half-unit membrane, with numerous microtubules running adjacently in different directions. The ER, no longer continuous with lipid bodies, makes contact with them through microtubules. At this stage, lipid synthesis takes place at the periphery of lipid bodies. This presumption, and a hypothesis that microtubules are involved in lipid synthesis delivering necessary components to lipid bodies, is based on strong arguments: (i) silver grains first appear over microtubules after a short [3H]palmitic acid incubation and before they are observed over lipid bodies; (ii) blockade of [3H]palmitic acid incorporation into lipotubuloids by propyzamide, an inhibitor of microtubule function; and (iii) the presence of gold grains above the microtubules after DGAT1 and DGAT2 reactions, as also near microtubules after an immunogold method that identifies phospholipase D1. PMID:22295975

Kwiatkowska, Maria; Pop?o?ska, Katarzyna; Wojtczak, Agnieszka; St?pi?ski, Dariusz; Polit, Justyna Teresa

2012-05-01

211

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)

2010-01-18

212

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

1997-01-01

213

S-layer-supported lipid membranes.  

PubMed

Many prokaryotic organisms (archaea and bacteria) are covered by a regularly ordered surface layer (S-layer) as the outermost cell wall component. S-layers are built up of a single protein or glycoprotein species and represent the simplest biological membrane developed during evolution. Pores in S-layers are of regular size and morphology, and functional groups on the protein lattice are aligned in well-defined positions and orientations. Due to the high degree of structural regularity S-layers represent unique systems for studying the structure, morphogenesis, and function of layered supramolecular assemblies. Isolated S-layer subunits of numerous organisms are able to assemble into monomolecular arrays either in suspension, at air/water interfaces, on planar mono- and bilayer lipid films, on liposomes and on solid supports (e.g. silicon wafers). Detailed studies on composite S-layer/lipid structures have been performed with Langmuir films, freestanding bilayer lipid membranes, solid supported lipid membranes, and liposomes. Lipid molecules in planar films and liposomes interact via their head groups with defined domains on the S-layer lattice. Electrostatic interactions are the most prevalent forces. The hydrophobic chains of the lipid monolayers are almost unaffected by the attachment of the S-layer and no impact on the hydrophobic thickness of the membranes has been observed. Upon crystallization of a coherent S-layer lattice on planar and vesicular lipid membranes, an increase in molecular order is observed, which is reflected in a decrease of the membrane tension and an enhanced mobility of probe molecules within an S-layer-supported bilayer. Thus, the terminology 'semifluid membrane' has been introduced for describing S-layer-supported lipid membranes. The most important feature of composite S-layer/lipid membranes is an enhanced stability in comparison to unsupported membranes. PMID:11143799

Schuster, B; Sleytr, U B

2000-09-01

214

Lipidated Peptidomimetics with Improved Antimicrobial Activity  

PubMed Central

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

2012-01-01

215

Actively maintained lipid nanodomains in biomembranes  

NASA Astrophysics Data System (ADS)

Lipid rafts, defined as domains rich in cholesterol and sphingolipids, are involved in many important plasma membrane functions. Recent studies suggest that the way cells handle membrane cholesterol is fundamental in the formation of such lateral heterogeneities. We propose to model the plasma membrane as a nonequilibrium phase-separating system where cholesterol is dynamically incorporated and released. The model shows how cellular regulation of membrane cholesterol may determine the nanoscale lipid organization when the lipid mixture is close to a phase separation boundary, providing a plausible mechanism for raft formation in vivo.

Gómez, Jordi; Sagués, Francesc; Reigada, Ramon

2008-02-01

216

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

2012-01-01

217

Lipid membrane reorganization induced by chemical recognition.  

PubMed Central

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

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

2001-01-01

218

A lipid E-MAP identifies Ubx2 as a critical regulator of lipid saturation and lipid bilayer stress.  

PubMed

Biological membranes are complex, and the mechanisms underlying their homeostasis are incompletely understood. Here, we present a quantitative genetic interaction map (E-MAP) focused on various aspects of lipid biology, including lipid metabolism, sorting, and trafficking. This E-MAP contains ?250,000 negative and positive genetic interaction scores and identifies a molecular crosstalk of protein quality control pathways with lipid bilayer homeostasis. Ubx2p, a component of the endoplasmic-reticulum-associated degradation pathway, surfaces as a key upstream regulator of the essential fatty acid (FA) desaturase Ole1p. Loss of Ubx2p affects the transcriptional control of OLE1, resulting in impaired FA desaturation and a severe shift toward more saturated membrane lipids. Both the induction of the unfolded protein response and aberrant nuclear membrane morphologies observed in cells lacking UBX2 are suppressed by the supplementation of unsaturated FAs. Our results point toward the existence of dedicated bilayer stress responses for membrane homeostasis. PMID:23891562

Surma, Michal A; Klose, Christian; Peng, Debby; Shales, Michael; Mrejen, Caroline; Stefanko, Adam; Braberg, Hannes; Gordon, David E; Vorkel, Daniela; Ejsing, Christer S; Farese, Robert; Simons, Kai; Krogan, Nevan J; Ernst, Robert

2013-08-22

219

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

PubMed Central

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

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

2012-01-01

220

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.

2009-01-01

221

Effect of different lipid extraction methods on delta13C of lipid and lipid-free fractions of fish and different fish feeds.  

PubMed

For many ecological applications of stable carbon isotope techniques, it is necessary to separate the lipid and lipid-free fractions. The effect of different lipid extraction methods on the isotope signature of the remaining lipid-free matter as well as the lipid fraction was tested. A hot extraction form of the Soxhlet method using petrol-ether was compared with two liquid-liquid extraction methods for lipid determination described by Bligh and Dyer and Smedes. Solid samples of fish and different natural food items were subjected to extraction and the carbon isotope ratios in lipid and lipid-free matter determined by IRMS. All methods were suitable for lipid extraction from all samples analysed here and did not cause biologically relevant differences (> 1%) in carbon isotopic ratios, except the Bligh and Dyer extraction method using chloroform which caused systematic errors for delta13C when applied to diatoms. PMID:12872805

Schlechtriem, Ch; Focken, U; Becker, K

2003-06-01

222

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

PubMed Central

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

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

1998-01-01

223

The relationship between serum lipids, nucleation time, and biliary lipids in patients with gallstones  

Microsoft Academic Search

Summary  The relationship between biliary lipids, cholesterol saturation index, nucleation time, and serum lipids was studied in a group of 45 gallstone patients (10 male, 35 female; age 50.1 ±14.5 years). Bile was obtained by direct fine-needle puncture of the gallbladder under local anesthesia and sonographic monitoring. No significant correlation between the serum lipids and either the cholesterol saturation index or

P. Janowitz; J. G. Wechsler; K. Kuhn; W. Kratzer; J. Tudyka; W. Swobodnik; H. Ditschuneit

1992-01-01

224

Direct determination of the lipid content in starch–lipid composites by time-domain NMR  

Microsoft Academic Search

Starch–lipid composites, prepared by excess steam jet cooking aqueous mixtures of starch and lipid, are used in a broad range of applications for which their performance can depend upon accurately knowing the amount of the lipid contributed by the composites. A rapid and non-destructive method based on time-domain nuclear magnetic resonance spectroscopy (TD-NMR) was evaluated to quantitate soybean oil (SBO)

James A. Kenar

2007-01-01

225

Lipid peroxides in obese patients and effects of weight loss with orlistat on lipid peroxides levels  

Microsoft Academic Search

OBJECTIVE:Obesity is a well-known risk factor of atherosclerosis. Recent studies showed that obesity is associated with enhanced lipid peroxidation. The aim of this study is to investigate the effect of weight reduction with orlistat treatment on lipid peroxidation levels. We assessed lipid peroxidation by measuring the concentration of plasma malondialdehyde (MDA).DESIGN:A randomized, controlled, open-label 6-month study.SUBJECTS:In total, 36 obese (body

D Yesilbursa; Z Serdar; A Serdar; M Sarac; S Coskun; C Jale

2005-01-01

226

Magainin 2 channel formation in planar lipid membranes: the role of lipid polar groups and ergosterol  

Microsoft Academic Search

Magainin 2, a polycationic peptide, displays bactericidal and tumoricidal activity, presumably interacting with negatively charged phospholipids in the membrane hosts. In this work, we investigate the role played by the lipid head-group in the interactions and self-association of magainin 2 during pore formation in lipid bilayers. Two methods are used: single-channel and macroscopic incorporation into planar lipid membranes. Single-channel incorporation

Enrico Gallucci; Daniela Meleleo; Silvia Micelli; Vittorio Picciarelli

2003-01-01

227

Glutathionylated products of lipid peroxidation  

PubMed Central

Obesity-associated insulin resistance has long been linked to both increased adipocyte oxidative stress as well as the presence of inflammatory changes in adipose tissue, including the infiltration and activation of tissue-resident macrophages. In order to investigate the connections between obesity-associated oxidative stress in adipocytes and increased inflammation in adipose tissue associated with the development of insulin resistance, our laboratory recently demonstrated that adipocytes form glutathionylated products of oxidative stress including glutathionyl-4-hydroxy-2-nonenal (GS-HNE) and glutathionyl-1,4-dihydroxynonene (GS-DHN). The abundance of both GS-HNE and GS-DHN were increased in the visceral adipose tissue of ob/ob mice and diet-induced obese, insulin-resistant mice. Further, these products of lipid peroxidation were shown to induce inflammatory changes in macrophages. Finally, in a mouse model, overproduction of GS-HNE was associated with increased fasting glucose levels and moderately impaired glucose tolerance. Together, these findings suggest a novel mechanism by which obesity-induced oxidative stress in adipocytes may lead to activation of tissue-resident macrophages. As adipose tissue inflammation has been shown to play an important role in the development of insulin resistance, further study of this pathway may lead to potential interventions to attenuate the metabolic consequences of obesity.

Frohnert, Brigitte I; Bernlohr, David A

2014-01-01

228

Hypersaline Microbial Mat Lipid Biomarkers  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

229

Lipid modified polyelectrolyte microcapsules with controlled diffusion.  

PubMed

The lipid coating introduced directly on (polystyrene sulfonate/polyallylamine hydrochloride)5 polyelectrolyte microcapsule surfaces significantly reduces the permeability of capsule walls estimated by fluorescence recovery after photobleaching (FRAP). PMID:15928761

Krishna, Gopal; Shutava, Tatsiana; Lvov, Yuri

2005-06-14

230

Biosynthesis of Membrane Lipids in Halobacterium Cutirubrum.  

National Technical Information Service (NTIS)

Incorporation of C14 into the lipids of the obligate halophile, Halobacterium cutirubrum grown in the presence of C14-labelled acetate, malonate, mevalonate or glycerol was investigated. Mevalonate showed the highest incorporation (8% of the amount suppli...

M. Kates M. K. Wassef D. J. Kushner

1968-01-01

231

Voltage-Gated Lipid Ion Channels  

PubMed Central

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

Blicher, Andreas; Heimburg, Thomas

2013-01-01

232

Overview of Cholesterol and Lipid Disorders  

MedlinePLUS

... Lipid Content Function Chylomicrons Formed from fats in food processed by the intestine Mostly triglycerides Transports digested fats (as triglycerides) to muscle and fat cells Very low density lipoprotein (VLDL) Formed in the liver More than ...

233

Lipophagy: Connecting Autophagy and Lipid Metabolism  

PubMed Central

Lipid droplets (LDs), initially considered “inert” lipid deposits, have gained during the last decade the classification of cytosolic organelles due to their defined composition and the multiplicity of specific cellular functions in which they are involved. The classification of LD as organelles brings along the need for their regulated turnover and recent findings support the direct contribution of autophagy to this turnover through a process now described as lipophagy. This paper focuses on the characteristics of this new type of selective autophagy and the cellular consequences of the mobilization of intracellular lipids through this process. Lipophagy impacts the cellular energetic balance directly, through lipid breakdown and, indirectly, by regulating food intake. Defective lipophagy has been already linked to important metabolic disorders such as fatty liver, obesity and atherosclerosis, and the age-dependent decrease in autophagy could underline the basis for the metabolic syndrome of aging.

Singh, Rajat; Cuervo, Ana Maria

2012-01-01

234

Intercellular Lipid Mediators and GPCR Drug Discovery  

PubMed Central

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

Im, Dong-Soon

2013-01-01

235

Lipid-lowering drugs and circulating adiponectin.  

PubMed

Pharmacological agents used to treat primary and combined hyperlipidemia reduce cardiovascular disease morbidity and mortality. Risk reduction has been attributed to improvements in blood lipid and lipoprotein characteristics. However, each class of available lipid-lowering drugs has been shown to exhibit pleiotropic effects that broaden their anticipated actions. Indeed, the results of a growing number of available studies suggest that a strong relationship exists between pharmacological reductions in blood lipids and circulating concentrations of the adipose tissue derived protein, adiponectin. Adiponectin is the most abundantly secreted protein from adipose tissue and has been shown to decrease hepatic glucose production, increase fatty acid oxidation in liver and skeletal muscle, and decrease vascular inflammation. In this chapter, we present a comprehensive analysis of the effects of the available classes of lipid-lowering drugs (statins, fibrates, niacin, and omega-3-fatty acids) on circulating adiponectin and the known mechanisms which produce these important events. PMID:23017722

Wanders, Desiree; Plaisance, Eric P; Judd, Robert L

2012-01-01

236

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

2011-01-01

237

Pharmacogenomics, lipid disorders, and treatment options.  

PubMed

Statins form the backbone of lipid-lowering therapy in the prevention of cardiovascular disease. Numerous studies have evaluated the effect of genomics on the clinical efficacy and adverse effects of statins. Several gene variants that can be linked to either the pharmacokinetics or pharmacodynamics of statins have been identified as potentially important, although there are some discrepant findings among studies. Effect sizes are modest for lipid-lowering efficacy and perhaps somewhat larger for risk of myopathy, although results are inconsistent. Pharmacogenomics of nonstatin lipid-lowering agents have not been evaluated to the same extent, given their relatively limited use, although there are some promising candidate genes for further study. Finally, with several new classes of lipid-lowering therapies soon becoming available, there may be a potential application for pharmacogenomics to identify patients ideally suited to receive-or those who should avoid-specific medications. PMID:24722394

Gryn, S E; Hegele, R A

2014-07-01

238

Effects of hormones on lipids and lipoproteins.  

National Technical Information Service (NTIS)

Levels of plasma lipids and lipoproteins are strong predictors for the development of atherosclerotic cardiovascular disease in postmenopausal women. In women, as in men, numerous factors contribute to variations in plasma lipoproteins that may affect car...

R. M. Krauss

1991-01-01

239

Protein entrapment in PEGylated lipid nanoparticles.  

PubMed

Defining appropriate delivery strategies of therapeutic proteins, based on lipid nanoparticulate carriers, requires knowledge of the nanoscale organization that determines the loading and release properties of the nanostructured particles. Nanoencapsulation of three cationic proteins (human brain-derived neurotrophic factor (BDNF), ?-chymotrypsinogen A, and histone H3) was investigated using anionic nanoparticle (NP) carriers. PEGylated lipid NPs were prepared from self-assembled liquid crystalline phases involving monoolein and eicosapentaenoic acid. Inclusion of the antioxidant ?-tocopherol favoured the preparation of stealth hexosome carriers. The purpose of the present work is to reveal the structural features of the protein-loaded lipid nanocarriers by means of high resolution small-angle X-ray scattering (SAXS) and cryogenic transmission electron microscopy (cryo-TEM). The obtained results indicate that protein entrapment is concentration-dependent and may significantly modify the inner liquid crystalline structure of the lipid nanocarriers through changes in the interfacial curvature and hydration. PMID:23791734

Angelova, Angelina; Angelov, Borislav; Drechsler, Markus; Garamus, Vasil M; Lesieur, Sylviane

2013-10-01

240

ER stress and hepatic lipid metabolism  

PubMed Central

The endoplasmic reticulum (ER) is an important player in regulating protein synthesis and lipid metabolism. Perturbation of ER homeostasis, referred as “ER stress,” has been linked to numerous pathological conditions, such as inflammation, cardiovascular diseases, and metabolic disorders. The liver plays a central role in regulating nutrient and lipid metabolism. Accumulating evidence implicates that ER stress disrupts lipid metabolism and induces hepatic lipotoxicity. Here, we review the major ER stress signaling pathways, how ER stress contributes to the dysregulation of hepatic lipid metabolism, and the potential causative mechanisms of ER stress in hepatic lipotoxicity. Understanding the role of ER stress in hepatic metabolism may lead to the identification of new therapeutic targets for metabolic diseases.

Zhou, Huiping; Liu, Runping

2014-01-01

241

Supported lipid bilayer/carbon nanotube hybrids.  

PubMed

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. PMID:18654251

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

2007-03-01

242

Comparative Structural Analysis of Lipid Binding START Domains  

Microsoft Academic Search

BackgroundSteroidogenic acute regulatory (StAR) protein related lipid transfer (START) domains are small globular modules that form a cavity where lipids and lipid hormones bind. These domains can transport ligands to facilitate lipid exchange between biological membranes, and they have been postulated to modulate the activity of other domains of the protein in response to ligand binding. More than a dozen

Ann-Gerd Thorsell; Wen Hwa Lee; Camilla Persson; Marina I. Siponen; Martina Nilsson; Robert D. Busam; Tetyana Kotenyova; Herwig Schüler; Lari Lehtiö; Nick Gay

2011-01-01

243

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.

R. R. MATSUO; J. E. DEXTER; A. BOUDREAU; J. K. DAUN

244

Evaluation of serum lipid abnormalities in chronic nephritis  

Microsoft Academic Search

Evaluation of serum lipid abnormalities in chronic nephritis.BackgroundIn glomerular disease, disorders of lipid metabolism are suspected as factors exacerbating glomerular dysfunction. Although many reports have been published regarding metabolic disorders of lipids in renal disease, including nephrotic syndrome and chronic renal failure, there have been few published reports describing metabolic disorders of lipids in chronic nephritis. Therefore, in patients with

Hiroko Hirano; Yoichi Yamada; Haruhisa Otani; Naoya Kodama; Masatoshi Mune; Susumu Yukawa

1999-01-01

245

Lipid Bilayer Pressure Profiles and Mechanosensitive Channel Gating  

Microsoft Academic Search

The function of membrane proteins often depends on the proteins’ interaction with their lipid environment, spectacularly so in the case of mechanosensitive channels, which are gated through tension mediated by the surrounding lipids. Lipid bilayer tension is distributed quite inhomogeneously, but neither the scale at which relevant variation takes place nor the effect of varying lipid composition or tension has

Justin Gullingsrud; Klaus Schulten

2004-01-01

246

Role of cholesterol and lipid organization in disease  

Microsoft Academic Search

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

Frederick R. Maxfield; Ira Tabas

2005-01-01

247

Lipid Composition of Purified Vesicular Stomatitis Viruses  

PubMed Central

Methods are described for the production of vesicular stomatitis (VS) virus of sufficient purity for reliable chemical analysis. VS virions released from infected cells were concentrated and purified at least 150-fold by sequential steps of precipitation with polyethylene glycol, column chromatography, rate zonal centrifugation, and equilibrium centrifugation. The Indiana serotype (VSInd virus) propagated in L-cells was found to contain 3% ribonucleic acid, 64% protein, 13% carbohydrate, and 20% lipid; the molar ratio of cholesterol to phospholipid was 0.6 or greater. Thin-layer chromatography revealed no unusual neutral lipids or phospholipids and gas-liquid chromatography revealed no unusual fatty acids incorporated into VS virions. The antigenically distinct New Jersey serotype (VSNJ virus) grown in L-cells showed a similar lipid profile except that the proportion of neutral lipids was larger than in VSInd virus also grown in L-cells. This differences was less pronounced when the lipid composition of VSInd and VSNJ viruses grown in chick embryo cells was compared, but VSNJ virus grown in either cell type always contained larger amounts of neutral lipids other than cholesterol than did VSInd virus. The lipid composition of both VSInd and VSNJ viruses grown in L-cells or chick embryo cells more closely resembled that of plasma membrane than of whole cells. A consistent finding was the relatively large amounts of phosphatidylethanolamine and sphingomyelin and the relatively small amounts of phosphatidylcholine in both VS viruses compared with uninfected whole L-cells and chick embryo cells or their plasma membranes. The methods available for isolation of plasma membranes were inadequate for conclusive comparison of the lipids of VS virions with the lipids of the plasma membranes of their host cells. Nevertheless, the data obtained are consistent with two hypotheses: (i) the lipid composition of VS viruses primarily reflects their membrane site of maturation, and (ii) the newly synthesized viral proteins inserted into cell membranes influence the proportions of phospholipids and neutral lipids selected for incorporation into the viral membrane.

McSharry, James J.; Wagner, Robert R.

1971-01-01

248

Effect of tamoxifen on erythrocyte membrane lipids, lipid peroxides, and antioxidative enzymes in breast cancer women.  

PubMed

Fasting blood samples were taken from 64 tamoxifen-treated postmenopausal women with early stage breast cancer. The levels of erythrocyte lipid peroxidation and the status of erythrocyte detoxifying enzymes were analyzed in untreated and treated patients for 3 months and 6 months with tamoxifen. Erythrocyte membrane lipid peroxidation and membrane cholesterol, phospholipid were also determined in all the patients. The 3 months and 6 months tamoxifen-treated patients showed significantly decreased levels of erythrocyte, erythrocyte membrane lipid peroxide with concomitantly increased levels of detoxifying enzymes when compared with baseline values of untreated women. Erythrocyte membrane cholesterol and phospholipid levels were markedly decreased in tamoxifen-treated patients than in untreated women. An interesting finding of this study indicates that the lipid peroxide, as well as, the lipid lowering efficacy of tamoxifen, was increased in patients with greater levels of baseline lipid and lipid peroxides in their erythrocyte membrane. These results indicate that tamoxifen is a potent suppressor of lipid peroxide formation through the favorable effects on membrane lipids and protective enzyme system. PMID:7767903

Thangaraju, M; Ezhilarasi, R; Sachdanandam, P

1995-01-01

249

Binary lipids-based nanostructured lipid carriers for improved oral bioavailability of silymarin.  

PubMed

The main purpose of this study was to prepare binary lipids-based nanostructured lipid carriers to improve the oral bioavailability of silymarin, a poorly water-soluble liver protectant. Silymarin-loaded nanostructured lipid carriers were prepared by the method of high-pressure homogenization with glycerol distearates (Precirol ATO-5) and oleic acid as the solid and liquid lipids, respectively, and lecithin (Lipoid E 100) and Tween-80 as the emulsifiers. The silymarin-nanostructured lipid carrier prepared under optimum conditions was spherical in shape with mean particle size of ?78.87?nm, entrapment efficiency of 87.55%, loading capacity of 8.32%, and zeta potential of -65.3?mV, respectively. In vitro release of silymarin-nanostructured lipid carriers was very limited even after 12?h, while in vitro lipolysis showed fast digestion of nanostructured lipid carriers within 1?h. Relative oral bioavailability of silymarin-nanostructured lipid carriers in Beagle dogs was 2.54- and 3.10-fold that of marketed Legalon® and silymarin solid dispersion pellets, respectively. It was concluded that nanostructured lipid carriers were potential drug delivery systems to improve the bioavailability of silymarin. Other than improved dissolution, alternative mechanisms such as facilitated absorption as well as lymphatic transport may contribute to bioavailability enhancement. PMID:24008629

Shangguan, Mingzhu; Lu, Yi; Qi, Jianping; Han, Jin; Tian, Zhiqiang; Xie, Yunchang; Hu, Fuqiang; Yuan, Hailong; Wu, Wei

2014-02-01

250

Pyruvate is a lipid precursor for rat lymphocytes in culture: evidence for a lipid exporting capacity.  

PubMed

Since acetyl-CoA produced through pyruvate dehydrogenase reaction is poorly oxidized by the Krebs cycle in rat lymphocytes, the fate of acetyl units was investigated in these cells. The results presented here show that 24-h cultured lymphocytes actively synthesize lipids from [3-14C]pyruvate. Furthermore, a considerable amount of these lipids have shown to be exported into the culture medium. Experiments with [1-14C] acetate as a lipid precursor showed a close similarity with the rates of incorporation of [3-14C] pyruvate into the same lipid fractions. Treatment of lymphocytes with the mitogen concanavalin A (Con A) markedly enhanced [1-14C] acetate incorporation into a variety of lipids, but the lectin did not affect [3-14C] pyruvate incorporation. The results suggest that lymphocytes convert pyruvate into lipids via the acetyl-CoA pathway and that Con A interferes in lymphocyte lipogenesis but does not seem to affect the pyruvate dehydrogenase reaction. The ability to incorporate pyruvate into certain lipids may have an important role for the rapidly dividing capacity of lymphocytes since the human cancer strain HeLa 155 (a quickly proliferating cell line) also exhibits this feature by converting much more [3-14C] pyruvate into lipids than do lymphocytes. In addition, comparative experiments with lymphocytes, peritoneal macrophages and HeLa cells indicate that pyruvate may provide precursors for cells with active lipid producing and exporting capacities. PMID:8401320

Homem de Bittencourt, P I; Peres, C M; Yano, M M; Hirata, M H; Curi, R

1993-07-01

251

Pediatric aspects of lipid-induced atherogenesis.  

PubMed

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

1984-01-01

252

Membrane protein dynamics: limited lipid control  

Microsoft Academic Search

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

Balázs Szalontai

2009-01-01

253

Interaction of lipid membrane with nanostructured surfaces.  

PubMed

Tiny details of the phospholipid (DMPC) membrane morphology in close vicinity to nanostructured silica surfaces have been discovered in the atomic force microscopy experiments. The structural features of the silica surface were varied in the experiments by the deposition of silica nanoparticles of different diameter on plane and smooth silica substrates. It was found that, due to the barrier function of the lipid membrane, only particles larger than 22 nm in diameter with a smooth surface were completely enveloped by the lipid membrane. However, nanoparticles with bumpy surfaces (curvature diameter of bumps as that of particles <22 nm) were only partially enveloped by the lipid bilayer. For the range of nanostructure dimensions between 1.2 and 22 nm, the lipid membrane underwent structural rearrangements by forming pores (holes). The nanoparticles were accommodated into the pores but not enveloped by the lipid bilayer. The study also found that the lipid membrane conformed to the substrate with surface structures of dimensions less than 1.2 nm without losing the membrane integrity. The experimental results are in accord with the analytical free energy model, which describes the membrane coverage, and numerical simulations which evaluate adhesion of the membrane and dynamics as a function of surface topology. The results obtained in this study are useful for the selection of dimensions and shapes for drug-delivery cargo and for the substrate for supported lipid bilayers. They also help in qualitative understanding the role of length scales involved in the mechanisms of endocytosis and cytotoxicity of nanoparticles. These findings provide a new approach for patterning supported lipid membranes with well-defined features in the 1.2-22 nm range. PMID:19466783

Roiter, Yuri; Ornatska, Maryna; Rammohan, Aravind R; Balakrishnan, Jitendra; Heine, David R; Minko, Sergiy

2009-06-01

254

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)

2001-11-30

255

Perfluorooctanoic acid rigidifies a model lipid membrane  

NASA Astrophysics Data System (ADS)

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

Brüning, B.; Farago, B.

2014-04-01

256

Modulation of lipid peroxidation by dietary components  

Microsoft Academic Search

The aqueous extracts of commonly consumed Indian spices and vegetables were tested for their antioxidant properties in human erythrocyte membranes against lipid peroxidation induced by FeSO4-ascorbate (10:100 ?mol\\/system). Aqueous extracts of curry leaves (Murraya koneigii) at 10 ?g\\/ml and of asafoetida (Ferula spp), omam (Carum ajowan) and mustard (Brassica nigra) at 300 ?g\\/ml inhibited lipid peroxidation by 90, 85, 75

R. Sujatha; L. Srinivas

1995-01-01

257

Nanostructure of Cationic Lipid-Oligonucleotide Complexes  

Microsoft Academic Search

Complexes (lipoplexes) between cationic liposomes and single-strand oligodeoxynucleotides (ODN) are potential delivery systems for antisense therapy. The nanometer-scale morphology of these assemblies is relevant to their transfection efficiency. In this work the monocationic lipid dioleoyloxytrimethylammoniumpropane, the neutral “helper” lipid cholesterol, and an 18-mer anti-bcl2 ODN were combined at different ratios. The lipoplexes formed were characterized for the quantity of ODN

Sarah Weisman; Danielle Hirsch-Lerner; Yechezkel Barenholz; Yeshayahu Talmon

2004-01-01

258

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

JOEY C. EISENMANN; CHRISTOPHER J. WOMACK; MAT J. REEVES; JAMES M. PIVARNIK; ROBERT M. MALINA

2001-01-01

259

Lipid component quantitation by thin layer chromatography.  

PubMed

This chapter describes a thin layer chromatography (TLC) method for the quantitation of various lipids (such as phospholipids, sphingolipids, acylglycerols, and fatty acids) in lipid-based nanoparticle formulations such as liposomes and nanoemulsions. We illustrate this technique to quantify C6-ceramide (N-hexanoyl-D: -erythro-sphingosine) in a nanoemulsion formulation. C6-ceramide is a powerful chemotherapeutic that is poorly soluble in aqueous buffers. PMID:21116959

Clogston, Jeffrey D; Patri, Anil K

2011-01-01

260

Biosynthesis and Function of Chloroplast Lipids  

Microsoft Academic Search

\\u000a Chloroplast membranes are composed of four unique lipids, including monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol\\u000a (DGDG), sulfoquinovosyldiacylglycerol (SQDG) and phosphatidyl-glycerol (PG). These lipids are crucial for maintaining the\\u000a function of chloroplasts not simply because they account for a large fraction of the photosynthetic membranes, but because\\u000a they are assembled into the photosynthetic machinery and are, therefore, directly involved in photosynthetic processes. Indeed,\\u000a Ara-bidopsis

Mie Shimojima; Hiroyuki Ohta; Yuki Nakamura

261

Measurement of lipid oxidation: A review  

Microsoft Academic Search

Lipids become rancid as a result of oxidation, and this oxidative rancidity is a major cause of food deterioration. The acceptability\\u000a of a food product depends on the extent to which this deterioration has occurred. Thus some criterion for assessing the extent\\u000a of oxidation is required. This paper reviews the experimental techniques for the measurement of lipid oxidation. The spectrum

J. I. Gray

1978-01-01

262

Ethanol enhances collective dynamics of lipid membranes  

NASA Astrophysics Data System (ADS)

Lipid bilayers have long been considered simple homogeneous passive barriers. However, there is a growing consensus that bilayer composition and properties impact their role in membrane function. One molecule which participates in lipid bilayers is ethanol. Ethanol is principally known to increase membrane permeability, serving as a model drug enhancer. While bilayer permeability was thought to depend solely on structural properties such as the area per lipid, this may be supported by thermal fluctuations in the bilayer core. Thermal motion results in the formation of small voids in the hydrocarbon chains, which may play a role in the transport small molecules through the membrane core. In both inelastic neutron scattering experiments and molecular dynamics simulations we find evidence for a new low-energy dynamic mode in the fluid phase of DMPC bilayers immersed in a 5% water/ethanol solution [1]. The molecular motion associated with this phonon corresponds to coherent displacements of the carbon atoms in the lipid tails both in, and partially normal to, the plane of the membrane. This finding supports the possibility of a fluctuation supported trans-membrane transport process in lipid bilayers. [4pt] [1] "Ethanol enhances collective dynamics of lipid membranes", M. D. Kaye, M. Tarek, K. Schmalzl, M. C. Rheinst"adter, submitted to Physical Review Letters

Kaye, Martin; Rheinstadter, Maikel

2011-03-01

263

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.

2009-01-01

264

LIPID SYNTHESIS, INTRACELLULAR TRANSPORT, AND SECRETION  

PubMed Central

In the mammary glands of lactating albino mice injected intravenously with 9, 10-oleic acid-3H or 9, 10-palmitic acid-3H, it has been shown that the labeled fatty acids are incorporated into mammary gland glycerides. The labeled lipid in the mammary gland 1 min after injection was in esterified form (> 95%), and the radioautographic reaction was seen over the rough endoplasmic reticulum and over lipid droplets, both intracellular and intraluminal. At 10–60 min after injection, the silver grains were concentrated predominantly over lipid droplets. There was no concentration of radioactivity over the granules in the Golgi apparatus, at any time interval studied. These findings were interpreted to indicate that after esterification of the fatty acid into glycerides in the rough endoplasmic reticulum an in situ aggregation of lipid occurs, with acquisition of droplet form. The release of the lipid into the lumen proceeds directly and not through the Golgi apparatus, in contradistinction to the mode of secretion of casein in the mammary gland or of lipoprotein in the liver. The presence of strands of endoplasmic reticulum attached to intraluminal lipid droplets provides a structural counterpart to the milk microsomes described in ruminant milk.

Stein, Olga; Stein, Yechezkiel

1967-01-01

265

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.

2011-12-01

266

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

1976-01-01

267

Modulation of lipid peroxidation by dietary components.  

PubMed

The aqueous extracts of commonly consumed Indian spices and vegetables were tested for their antioxidant properties in human erythrocyte membranes against lipid peroxidation induced by FeSO(4)-ascorbate (10:100 mumol/system). Aqueous extracts of curry leaves (Murraya koneigii) at 10 mug/ml and of asafoetida (Ferula spp), omam (Carum ajowan) and mustard (Brassica nigra) at 300 mug/ml inhibited lipid peroxidation by 90, 85, 75 and 70%, respectively. The aqueous extracts of cabbage (Brassica oleracea), ginger (Zinziber officinale) and onion (Allium cepa) inhibited lipid peroxidation by 65, 72 and 66%, respectively. The aqueous extracts of spices were also found to inhibit the formation of diene, triene and tetraene conjugates in human erythrocyte membrane. Addition of lipid peroxides extracted from peroxidized human erythrocyte membrane substantially increased erythrocyte lysis over that caused by exposure to 0.54% saline alone. Aqueous extracts of omam, coriander seeds (Coriandrum sativum) and curry leaves, at 300 mug/ml, inhibited peroxidized lipid-induced lysis by 67, 72 and 87%, respectively. Lipid peroxides induced considerable activation of polymorphonuclear leucocytes activation and this activation was inhibited by the aqueous extract of curry leaves. PMID:20650083

Sujatha, R; Srinivas, L

1995-06-01

268

Lipid Droplets and Mycobacterium leprae Infection  

PubMed Central

Leprosy is a chronic infectious disease and is a major source of morbidity in developing countries. Leprosy is caused by the obligate intracellular bacterium Mycobacterium leprae, which infects as primary target Schwann cells. Lepromatous leprosy exhibits multiple lesions of the skin, eyes, nerves, and lymph nodes. The sites of infection are characterized by the presence of foamy macrophages, fully packed with lipid droplets (LDs), which are induced by M. leprae. In the last years, it has become evident that M. tuberculosis imports lipids from foamy macrophages and is dependent on fatty acids for growth in infected macrophages. M. leprae seems to have similar mechanisms for scavenging lipids from the host. But due to the inability to culture M. leprae on laboratory media, research progresses only slowly. However, in the last years, substantial progress has been made in the field of lipid metabolism in M. leprae. Herein, we will present and summarize the lipid droplets formation and the metabolism of lipids during M. leprae infection.

Elamin, Ayssar A.; Stehr, Matthias; Singh, Mahavir

2012-01-01

269

RHODOPSIN-LIPID INTERACTIONS STUDIED BY NMR  

PubMed Central

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

Soubias, Olivier; Gawrisch, Klaus

2012-01-01

270

Conformational analysis of suloctidil and derivatives inserted in lipid layers.  

PubMed

Interaction between suloctidil (CP 556 S) and lipids (phosphatidylcholine, phosphatidylserine) is studied using a new conformational analysis procedure. This analysis is extended to two compounds related to suloctidil but bearing no protonable group (CP 894 S) or of different hydrophobicity (CP 1136 S). It gives a molecular description of the mode of insertion of the drugs into the lipid layer. The influence of the calculated lipid-drug interaction and area occupied per drug molecule in the lipid layer is tentatively related to the effect on the lipid dynamics. For a given conformer, an effect on the lipid dynamics is expected only if (a) the area occupied per conformer is similar to that of the lipid and/or (b) the drug-lipid interaction energy is equal or superior to that of the lipid-lipid interaction. These predictions are analyzed in terms of the available experimental data. PMID:6324809

Brasseur, R; Ruysschaert, J M; Chatelain, P

1984-04-01

271

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

2008-01-01

272

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

2005-01-01

273

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

1996-01-01

274

Cholecystokinin Elevates Mouse Plasma Lipids  

PubMed Central

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.

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

2012-01-01

275

Binding of peripheral proteins to mixed lipid membranes: effect of lipid demixing upon binding.  

PubMed

Binding isotherms have been determined for the association of horse heart cytochrome c with dioleoyl phosphatidylglycerol (DOPG)/dioleoyl phosphatidylcholine (DOPC) bilayer membranes over a range of lipid compositions and ionic strengths. In the absence of protein, the DOPG and DOPC lipids mix nearly ideally. The binding isotherms have been analyzed using double layer theory to account for the electrostatics, either the Van der Waals or scaled particle theory equation of state to describe the protein surface distribution, and a statistical thermodynamic formulation consistent with the mass-action law to describe the lipid distribution. Basic parameters governing the electrostatics and intrinsic binding are established from the binding to membranes composed of anionic lipid (DOPG) alone. Both the Van der Waals and scaled particle equations of state can describe the effects of protein distribution on the DOPG binding isotherms equally well, but with different values of the maximum binding stoichiometry (13 lipids/protein for Van der Waals and 8 lipids/protein for scaled particle theory). With these parameters set, it is then possible to derive the association constant, Kr, of DOPG relative to DOPC for surface association with bound cytochrome c by using the binding isotherms obtained with the mixed lipid membranes. A value of Kr (DOPG:DOPC) = 3.3-4.8, depending on the lipid stoichiometry, is determined that consistently describes the binding at different lipid compositions and different ionic strengths. Using the value of Kr obtained it is possible to derive the average in-plane lipid distribution and the enhancement in protein binding induced by lipid redistribution using the statistical thermodynamic theory. PMID:10233072

Heimburg, T; Angerstein, B; Marsh, D

1999-05-01

276

Fatty Acids from Membrane Lipids Become Incorporated into Lipid Bodies during Myxococcus xanthus Differentiation.  

PubMed

Myxococcus xanthus responds to amino acid limitation by producing fruiting bodies containing dormant spores. During development, cells produce triacylglycerides in lipid bodies that become consumed during spore maturation. As the cells are starved to induce development, the production of triglycerides represents a counterintuitive metabolic switch. In this paper, lipid bodies were quantified in wild-type strain DK1622 and 33 developmental mutants at the cellular level by measuring the cross sectional area of the cell stained with the lipophilic dye Nile red. We provide five lines of evidence that triacylglycerides are derived from membrane phospholipids as cells shorten in length and then differentiate into myxospores. First, in wild type cells, lipid bodies appear early in development and their size increases concurrent with an 87% decline in membrane surface area. Second, developmental mutants blocked at different stages of shortening and differentiation accumulated lipid bodies proportionate with their cell length with a Pearson's correlation coefficient of 0.76. Third, peripheral rods, developing cells that do not produce lipid bodies, fail to shorten. Fourth, genes for fatty acid synthesis are down-regulated while genes for fatty acid degradation are up regulated. Finally, direct movement of fatty acids from membrane lipids in growing cells to lipid bodies in developing cells was observed by pulse labeling cells with palmitate. Recycling of lipids released by Programmed Cell Death appears not to be necessary for lipid body production as a fadL mutant was defective in fatty acid uptake but proficient in lipid body production. The lipid body regulon involves many developmental genes that are not specifically involved in fatty acid synthesis or degradation. MazF RNA interferase and its target, enhancer-binding protein Nla6, appear to negatively regulate cell shortening and TAG accumulation whereas most cell-cell signals activate these processes. PMID:24906161

Bhat, Swapna; Boynton, Tye O; Pham, Dan; Shimkets, Lawrence J

2014-01-01

277

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

PubMed Central

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

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

2012-01-01

278

Fatty Acids from Membrane Lipids Become Incorporated into Lipid Bodies during Myxococcus xanthus Differentiation  

PubMed Central

Myxococcus xanthus responds to amino acid limitation by producing fruiting bodies containing dormant spores. During development, cells produce triacylglycerides in lipid bodies that become consumed during spore maturation. As the cells are starved to induce development, the production of triglycerides represents a counterintuitive metabolic switch. In this paper, lipid bodies were quantified in wild-type strain DK1622 and 33 developmental mutants at the cellular level by measuring the cross sectional area of the cell stained with the lipophilic dye Nile red. We provide five lines of evidence that triacylglycerides are derived from membrane phospholipids as cells shorten in length and then differentiate into myxospores. First, in wild type cells, lipid bodies appear early in development and their size increases concurrent with an 87% decline in membrane surface area. Second, developmental mutants blocked at different stages of shortening and differentiation accumulated lipid bodies proportionate with their cell length with a Pearson's correlation coefficient of 0.76. Third, peripheral rods, developing cells that do not produce lipid bodies, fail to shorten. Fourth, genes for fatty acid synthesis are down-regulated while genes for fatty acid degradation are up regulated. Finally, direct movement of fatty acids from membrane lipids in growing cells to lipid bodies in developing cells was observed by pulse labeling cells with palmitate. Recycling of lipids released by Programmed Cell Death appears not to be necessary for lipid body production as a fadL mutant was defective in fatty acid uptake but proficient in lipid body production. The lipid body regulon involves many developmental genes that are not specifically involved in fatty acid synthesis or degradation. MazF RNA interferase and its target, enhancer-binding protein Nla6, appear to negatively regulate cell shortening and TAG accumulation whereas most cell-cell signals activate these processes.

Bhat, Swapna; Boynton, Tye O.; Pham, Dan; Shimkets, Lawrence J.

2014-01-01

279

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

PubMed Central

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 diameter, which forms spontaneously, and remains stable on at least the microsecond time scale. The results give credence to the hotly debated existence of mobile neutral lipid aggregates of unknown function present in malignant cells, and to the early biogenesis of lipid droplets accommodated between the two leaflets of the endoplasmic reticulum membrane. The TO aggregates give the bilayer a blister-like appearance, and will hinder the formation of multi-lamellar phases in model, and possibly living membranes. The blisters will result in anomalous membrane probe partitioning, which should be accounted for in the interpretation of probe-related measurements.

Khandelia, Himanshu; Duelund, Lars; Pakkanen, Kirsi I.; Ipsen, John H.

2010-01-01

280

Immune response of rabbits to lipid A: influence of immunogen preparation and distribution of various lipid A specificities.  

PubMed Central

Sixty-two rabbit anti-lipid A serum samples were compared with respect to the immunogens used (synthetic lipid A and partial structures, natural lipid A, or acid-treated bacteria). Immunoglobulin (Ig) type-specific differences in rabbit response between liposomal membrane-embedded (LME) and other lipid A immunogens were found: LME lipid A elicited predominantly IgM antibodies. Previous findings of equally good immune responses to synthetic lipid A and acid-treated bacteria (L. Brade, E.T. Rietschel, S. Kusumoto, T. Shiba, and H. Brade, Infect. Immun. 51:110-114, 1986, and L. Brade, E.T. Rietschel, S. Kusumoto, T. Shiba, and H. Brade, Prog. Clin. Biol. Res. 231:75-97, 1987) turned out to be restricted to complement-fixing antibodies; IgG titers of sera against free lipid A (whether synthetic or natural) were significantly lower than those raised with bacteria. The results indicated an increase in IgG content of sera from LME lipid A over other free lipid A immunogens to acid-treated bacteria. These data underline the importance of the physicochemical environment for the immunogenicity of lipid A. As a second objective, the presence of various lipid A antibody specificities was tested with synthetic lipid A antigens. Antibodies to monophosphoryl lipid A were detected only in sera raised with monophosphoryl immunogens. Reactivity with monosaccharide partial structures of lipid A was found both in sera against monophosphoryl lipid A and in 60% of sera against bisphosphoryl lipid A. In the former, monosaccharide reactivity was of a magnitude similar to that of reactivity with lipid A; in sera against bisphosphoryl lipid A, it was lower. No reactivity or only marginal reactivity was found with phosphate-free lipid A, thus emphasizing the role of phosphate substitution for the lipid A epitopes recognized.

Kuhn, H M

1993-01-01

281

Algal Lipids as Quantitative Paleosalinity Proxies  

NASA Astrophysics Data System (ADS)

The tropics play an important role in driving climate. However it is difficult to uncover past changes in tropical precipitation due to a lack of tree ring records and low accumulation rates of marine sediments. Hydrogen isotope ratios of algal lipids preserved in lacustrine and marine sediments have been used to qualitatively reconstruct tropical paleohydrology. Changes in the hydrologic balance are reflected in salinity and in lake water D/H ratios, which are closely tracked by lipid D/H ratios of algal biomarkers. While useful for determining past periods of "wetter" or "drier" conditions, variability in isotope fractionation in algal lipids during lipid biosynthesis can be exploited to more quantitatively determine how much wetter or drier conditions were in the past. The estuarine diatom, Thalassiosira pseudonnana, was grown in continuous cultures under controlled light, temperature, nutrient, and growth rate conditions to assess the influence of salinity (9-40 PSU) on D/H fractionation between lipids and source water. Three fatty acids, 24-methylcholesta-5,24(28)-dien-3B-ol, and phytol show decreasing fractionation between lipid and source water as salinity increases with 0.8-1.3‰ change in fractionation per salinity unit. These results compliment field-based empirical observations of dinosterol in Chesapeake Bay suspended particles that change 0.99‰ per salinity unit and lipid biomarkers from hyper-saline ponds on Christmas Island that change 0.7-1.1‰ per salinity unit. Biological pathways responsible for the inverse relationship between fractionation and salinity will be discussed.

Maloney, A.; Shinneman, A.; Hemeon, K.; Sachs, J. P.

2012-12-01

282

Autophagy and Regulation of Lipid Metabolism  

PubMed Central

Macroautophagy (henceforth referred to as autophagy) is an in-bulk lysosomal degradative pathway that plays a crucial role in the maintenance of cellular homeostasis through the removal of damaged proteins and aged organelles. Following nutrient deprivation, a primary cellular response is the induction of autophagy that breaks down redundant cellular components and provides amino acids and additional precursor molecules for processes critical for cellular survival. In parallel, nutrient depletion leads to the mobilization of cellular lipid stores to supply free fatty acids for energy, thus pointing to regulatory and functional similarities between autophagy and lipid metabolism. The current chapter discusses the novel and mutually exclusive roles of autophagy in the regulation of lipid metabolism in the liver and of fat storage within the adipose tissue. Our studies in cultured hepatocytes and the murine liver have demonstrated that autophagy serves to degrade intracellular lipid stores through a process that we have termed “macrolipophagy” and that ablation of liver-specific autophagy leads to excessive hepatic lipid accumulation and the development of fatty liver. In contrast, preadipocytes in culture that lacked autophagy failed to differentiate into mature adipocytes and exhibited a reduction in fat storage that translated to decreased adipose tissue mass in an in vivo mouse model. These recent findings establish an association between autophagy and regulation of hepatic lipid metabolism and adipose tissue biology, thus providing new mechanistic insights into the regulation of these complex processes. These findings also highlight the possibility of novel therapeutic approaches, such as differential organ-specific regulation of autophagy to solve problems that arise from lipid over accumulation that occur in the metabolic syndrome and with aging.

Singh, Rajat

2014-01-01

283

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

2012-01-01

284

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

2008-01-01

285

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

PubMed

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

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

2013-05-01

286

Effect of lipid composition and packing on the adsorption of apolipoproteins to lipid monolayers  

SciTech Connect

The monolayer system has been used to study the effects of lipoprotein surface lipid composition and packing on the affinities of apolipoproteins for the surfaces of lipoprotein particles. The adsorption of apolipoproteins injected beneath lipid monolayers prepared with pure lipids or lipoprotein surface lipids is evaluated by monitoring the surface pressure of the film and the surface concentration (Gamma) of /sup 14/C-labelled apolipoprotein. At a given initial film pressure (..pi../sub i/) there is a higher adsorption of human apo A-I to unsaturated phosphatidylcholine (PC) monolayers compared to saturated PC monolayers (e.g., at ..pi../sub i/ = 10 mN/m, Gamma = 0.35 and 0.06 mg/m/sup 2/ for egg PC and distearoyl PC, respectively, with 3 x 10/sup -4/ mg/ml apo A-I in the subphase). In addition, adsorption of apo A-I is less to an egg sphingomyelin monolayer than to an egg PC monolayer. The adsorption of apo A-I to PC monolayers is decreased by addition of cholesterol. Generally, apo A-I adsorption diminishes as the lipid molecular area decreases. Apo A-I adsorbs more to monolayers prepared with HDL/sub 3/ surface lipids than with LDL surface lipids. These studies suggest that lipoprotein surface lipid composition and packing are crucial factors influencing the transfer and exchange of apolipoproteins among various lipoprotein classes during metabolism of lipoprotein particles.

Ibdah, J.A.; Lund-Katz, S.; Phillips, M.C.

1987-05-01

287

Lipid Accumulation, Lipid Body Formation, and Acyl Coenzyme A Oxidases of the Yeast Yarrowia lipolytica  

Microsoft Academic Search

Yarrowia lipolytica contains five acyl-coenzyme A oxidases (Aox), encoded by the POX1 to POX5 genes, that catalyze the limiting step of peroxisomal -oxidation. In this study, we analyzed morphological changes of Y. lipolytica growing in an oleic acid medium and the effect of POX deletions on lipid accumulation. Protrusions involved in the uptake of lipid droplets (LDs) from the medium

K. Mlickova; Emeline Roux; Karin Athenstaedt; Sabine d'Andrea; Gunther Daum; Thierry Chardot; Jean-Marc Nicaud

2004-01-01

288

Biodegradable lipids enabling rapidly eliminated lipid nanoparticles for systemic delivery of RNAi therapeutics.  

PubMed

In recent years, RNA interference (RNAi) therapeutics, most notably with lipid nanoparticle-based delivery systems, have advanced into human clinical trials. The results from these early clinical trials suggest that lipid nanoparticles (LNPs), and the novel ionizable lipids that comprise them, will be important materials in this emerging field of medicine. A persistent theme in the use of materials for biomedical applications has been the incorporation of biodegradability as a means to improve biocompatibility and/or to facilitate elimination. Therefore, the aim of this work was to further advance the LNP platform through the development of novel, next-generation lipids that combine the excellent potency of the most advanced lipids currently available with biodegradable functionality. As a representative example of this novel class of biodegradable lipids, the lipid evaluated in this work displays rapid elimination from plasma and tissues, substantially improved tolerability in preclinical studies, while maintaining in vivo potency on par with that of the most advanced lipids currently available. PMID:23799535

Maier, Martin A; Jayaraman, Muthusamy; Matsuda, Shigeo; Liu, Ju; Barros, Scott; Querbes, William; Tam, Ying K; Ansell, Steven M; Kumar, Varun; Qin, June; Zhang, Xuemei; Wang, Qianfan; Panesar, Sue; Hutabarat, Renta; Carioto, Mary; Hettinger, Julia; Kandasamy, Pachamuthu; Butler, David; Rajeev, Kallanthottathil G; Pang, Bo; Charisse, Klaus; Fitzgerald, Kevin; Mui, Barbara L; Du, Xinyao; Cullis, Pieter; Madden, Thomas D; Hope, Michael J; Manoharan, Muthiah; Akinc, Akin

2013-08-01

289

Interaction of lipid-transport proteins from Nigella sativa seeds with lipid membranes  

Microsoft Academic Search

Three pure lipid-transport proteins (LTPs) were isolated from Nigella sativa seeds. The effects of the three LTPs on release\\u000a of ANTS probe from the inner volume were studied using fluorescence in liposomes of different lipid composition. It was shown\\u000a that all LTPs had a dose-dependent effect on the liposome permeability.

Yu. I. Oshchepkova; S. Son’kina; B. A. Salakhutdinov; O. N. Veshkurova; E. A. Rogozhin; Ts. A. Egorov; T. F. Aripov; Sh. I. Salikhov

2010-01-01

290

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

PubMed Central

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

1991-01-01

291

Synthesis of Lipids for Development of Multifunctional Lipid-Based Drug-Carriers  

PubMed Central

A simple approach to synthesize phospholipids to modulate drug release and track lipid-based particulate drug-carriers is described. We synthesized two ether lipids, 1 1-O-hexadecyl-2-pentadenoyl-sn-glycerol-3-phosphocholine (C31PC) and 2 1-O-hexadecyl-2-pentadenoyl-sn-glycerol-3-phosphomethanol (C31PM), and examined their ability to alter enzymatically triggered release of 6-carboxyfluorescein from liposomes incubated in TRIS buffer or fetal bovine serum solutions. Further, we demonstrated that odd-chain lipids, e.g., C31PC, could be identified in rat plasma without interference of endogenous lipids. This approach can be adapted to synthesize a variety of lipids for use in developing and optimizing multifunctional drug-carriers.

Zhu, Guodong; Hamhoom, Yahya Al; Cummings, Brian S.; Arnold, Robert D.

2011-01-01

292

Cholesterol and Lipid Phases Influence the Interactions between Serotonin Receptor Agonists and Lipid Bilayers*  

PubMed Central

Solid state NMR techniques have been used to investigate the effect that two serotonin receptor 1a agonists (quipazine and LY-165,163) have on the phase behavior of, and interactions within, cholesterol/phosphocholine lipid bilayers. The presence of agonist, and particularly LY-165,163, appears to widen the phase transitions, an effect that is much more pronounced in the presence of cholesterol. It was found that both agonists locate close to the cholesterol, and their interactions with the lipids are modulated by the lipid phases. As the membrane condenses into mixed liquid-ordered/disordered phases, quipazine is pushed up toward the surface of the bilayer, whereas LY-165,163 moves deeper into the lipid chain region. In light of our results, we discuss the role of lipid/drug interactions on drug efficacy.

Batchelor, Rebecca; Windle, Christopher J.; Buchoux, Sebastien; Lorch, Mark

2010-01-01

293

Theoretical and simulation study of lipid membranes  

NASA Astrophysics Data System (ADS)

It has been established that a proper functioning of biological lipid membranes is in large part due to cholesterol's ability to regulate fluidity of a lipid bilayer. In particular, a growing body of evidence suggested that cholesterol participates in the formation of cholesterol- and sphingolipid-enriched phase-separated domains known as "rafts" in the plasma and other membranes of animal cells. Rafts have been identified as important membrane structural components in signal transduction, protein transport and sorting of membrane components. At a molecular level, the detailed, localized behavior of lipid-cholesterol bilayers is unclear. In order to better understand how cholesterols function in lipid membranes it is desirable to built theoretical models. The goal of the present research is to model lipid-cholesterol bilayers on the different length and timescales. In the first part of the work, mixtures of sphingomyelin (SM) lipid and cholesterol at different temperatures and cholesterol concentrations were investigated using Molecular Dynamics and Monte-Carlo simulation techniques. The objective was to study the properties of cholesterol- and SM-enriched raft-like domains at the atomic level. The simulations revealed that, addition of 31% cholesterol induced intermediate degree of organization in the model SM-cholesterol bilayers at temperatures below and above the main phase transition temperature of pure SM bilayer. This intermediate state of fluidity may be necessary for the binding of proteins and other molecules that associate with raft domains. In the second part of the work, dynamical self-consistent mean-field model based on atomistic simulations was developed to investigate phase properties of lipid-cholesterol bilayers on the length and timescales currently unreachable with traditional atomistic level simulation methods. This new technique allows studying systems consisting of 104 or more number of molecules, on microsecond timescales. The model was applied to dipalmitoylphosphatidylcholine lipid-cholesterol bilayers at 50°C temperature and for the range of cholesterol concentrations. Over the 20 mus simulation timescale the model predicted the continuous change in lipid chain order with increasing cholesterol content. No large-scale cholesterol-rich and cholesterol-depleted coexisting phase separated regions were observed at any cholesterol concentration.

Khelashvili, George

294

Alzheimer A? peptide interactions with lipid membranes  

PubMed Central

Fibrillar aggregates of misfolded amyloid proteins are involved in a variety of diseases such as Alzheimer disease (AD), type 2 diabetes, Parkinson, Huntington and prion-related diseases. In the case of AD amyloid ? (A?) peptides, the toxicity of amyloid oligomers and larger fibrillar aggregates is related to perturbing the biological function of the adjacent cellular membrane. We used atomistic molecular dynamics (MD) simulations of A?9–40 fibrillar oligomers modeled as protofilament segments, including lipid bilayers and explicit water molecules, to probe the first steps in the mechanism of A?-membrane interactions. Our study identified the electrostatic interaction between charged peptide residues and the lipid headgroups as the principal driving force that can modulate the further penetration of the C-termini of amyloid fibrils or fibrillar oligomers into the hydrophobic region of lipid membranes. These findings advance our understanding of the detailed molecular mechanisms and the effects related to A?-membrane interactions, and suggest a polymorphic structural character of amyloid ion channels embedded in lipid bilayers. While inter-peptide hydrogen bonds leading to the formation of ?-strands may still play a stabilizing role in amyloid channel structures, these may also present a significant helical content in peptide regions (e.g., termini) that are subject to direct interactions with lipids rather than with neighboring A? peptides.

Tofoleanu, Florentina; Buchete, Nicolae-Viorel

2012-01-01

295

Ultrasonication assisted lipid extraction from oleaginous microorganisms.  

PubMed

Various solvents, including water, hexane, methanol, and chloroform/methanol (1:1 v/v), were tested to identify the efficiency of lipid extraction from Trichosporon oleaginosus and an oleaginous fungal strain SKF-5 under ultrasonication (520kHz 40W and 50Hz 2800W) and compared with the conventional chloroform methanol (2:1 v/v) extraction method. The highest lipid recovery 10.2% and 9.3% with water, 43.2% and 33.2% with hexane, 75.7% and 65.1% with methanol, 100% and 100% w/w biomass with chloroform/methanol were obtained from T. oleaginosus and SKF-5 strain, respectively, at ultrasonication frequency 50Hz and power input 2800W. Ultrasonication chloroform/methanol extraction recovered total lipid in a short time (15min) and low temperature (25°C). Whereas the conventional chloroform methanol extraction to achieve total lipid recovery required 12h at 60°C. Ultrasonication chloroform/methanol extraction would be a promising method of lipid extraction from the microorganisms. PMID:24607462

Zhang, Xiaolei; Yan, Song; Tyagi, Rajeshwar D; Drogui, Patrick; Surampalli, Rao Y

2014-04-01

296

Chemical composition of Desulfovibrio desulfuricans lipid A  

PubMed Central

Lipopolysaccharides also called endotoxins are an integral component of the outer membrane of Gram-negative bacteria. When released from the bacterial surface, they interact with a host immune system, triggering excessive inflammatory response. Lipid A is the biologically most active part of endotoxin, and its activity is modulated by the quantity, quality and arrangement of its fatty acids. Desulfovibrio desulfuricans is sulfate-reducing, Gram-negative bacterium that is supposed to be opportunistic pathogens of humans and animals. In the present study, chemical composition of lipid A from various strains of D. desulfuricans was analyzed by gas chromatography/mass spectrometry. It was found that the fatty acid component of the lipid A contains dodecanoic, tetradecanoic, 3-hydroxytetradecanoic and hexadecanoic acids, and its carbohydrate core is composed of glucosamine. The analysis of 3-acyloxyacyl residue of the lipid A revealed the presence of amide-bound 3-(dodecanoyloxy)tetradecanoic and 3-(hexadecanoyloxy)tetradecanoic acids and ester-bound 3-(tetradecanoyloxy)tetradecanoic acid. It was concluded that both fatty acid and 3-acyloxyacyl residue profiles of the lipid A from the studied bacteria were similar to those of E. coli and S.enterica.

Lodowska, Jolanta; Jaworska-Kik, Marzena; Kurkiewicz, Slawomir; Weglarz, Ludmila; Dzierzewicz, Zofia

2010-01-01

297

Lipid binding proteins from parasitic platyhelminthes  

PubMed Central

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

Alvite, Gabriela; Esteves, Adriana

2012-01-01

298

Simulation Studies of Stratum Corneum Lipid Mixtures  

PubMed Central

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

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

2009-01-01

299

Nanosecond lipid dynamics in membranes containing cholesterol.  

PubMed

Lipid dynamics in the cholesterol-rich (40 mol%) liquid-ordered (lo) phase of dimyristoylphosphatidylcholine membranes were studied using neutron spin-echo and neutron backscattering. Recent theoretical and experimental evidence supports the notion of the liquid-ordered phase in phospholipid membranes as a locally structured liquid, with small ordered 'domains' of a highly dynamic nature in equilibrium with a disordered matrix [S. Meinhardt, R. L. C. Vink and F. Schmid, Proc. Natl. Acad. Sci. U. S. A., 2013, 110(12), 4476-4481, C. L. Armstrong et al., PLoS One, 2013, 8(6), e66162]. This local structure was found to have a pronounced impact on the membranes' dynamical properties. We found that the long-wavelength dynamics in the liquid-ordered phase, associated with the elastic properties of the membranes, were faster by two orders of magnitude as compared to the liquid disordered phase. At the same time, collective nanoscale diffusion was significantly slower. The presence of a soft-mode (a slowing down) in the long-wavelength dispersion relationship suggests an upper size limit for the ordered lipid domain of ?220 Å. Moreover, from the relaxation rate of the collective lipid diffusion of lipid-lipid distances, the lifetime of these domains was estimated to be about 100 nanoseconds. PMID:24647350

Armstrong, Clare L; Häussler, Wolfgang; Seydel, Tilo; Katsaras, John; Rheinstädter, Maikel C

2014-04-21

300

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.

2013-01-01

301

Preservation of microbial lipids in geothermal sinters.  

PubMed

Lipid biomarkers are widely used to study the earliest life on Earth and have been invoked as potential astrobiological markers, but few studies have assessed their survival and persistence in geothermal settings. Here, we investigate lipid preservation in active and inactive geothermal silica sinters, with ages of up to 900 years, from Champagne Pool, Waiotapu, New Zealand. Analyses revealed a wide range of bacterial biomarkers, including free and bound fatty acids, 1,2-di-O-alkylglycerols (diethers), and various hopanoids. Dominant archaeal lipids include archaeol and glycerol dialkyl glycerol tetraethers (GDGTs). The predominance of generally similar biomarker groups in all sinters suggests a stable microbial community throughout Champagne Pool's history and indicates that incorporated lipids can be well preserved. Moreover, subtle differences in lipid distributions suggest that past changes in environmental conditions can be elucidated. In this case, higher archaeol abundances relative to the bacterial diethers, a greater proportion of cyclic GDGTs, the high average chain length of the bacterial diethers, and greater concentrations of hopanoic acids in the older sinters all suggest hotter conditions at Champagne Pool in the past. PMID:21476896

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

2011-04-01

302

Drug targeting using solid lipid nanoparticles.  

PubMed

The present review aims to show the features of solid lipid nanoparticles (SLNs) which are at the forefront of the rapidly developing field of nanotechnology with several potential applications in drug delivery and research. Because of some unique features of SLNs such as their unique size dependent properties it offers possibility to develop new therapeutics. A common denominator of all these SLN-based platforms is to deliver drugs into specific tissues or cells in a pathological setting with minimal adverse effects on bystander cells. SLNs are capable to incorporate drugs into nanocarriers which lead to a new prototype in drug delivery which maybe used for drug targeting. Hence solid lipid nanoparticles hold great promise for reaching the goal of controlled and site specific drug delivery and hence attracted wide attention of researchers. This review presents a broad treatment of targeted solid lipid nanoparticles discussing their types such as antibody SLN, magnetic SLN, pH sensitive SLN and cationic SLN. PMID:24717692

Rostami, Elham; Kashanian, Soheila; Azandaryani, Abbas H; Faramarzi, Hossain; Dolatabadi, Jafar Ezzati Nazhad; Omidfar, Kobra

2014-07-01

303

Peptide-lipid interactions: experiments and applications.  

PubMed

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

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

2013-01-01

304

Apolipoprotein gene involved in lipid metabolism  

DOEpatents

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) [Berkeley, CA; Pennacchio, Len A. (Sebastopol, CA) [Sebastopol, CA

2007-07-03

305

Lipids as universal biomarkers of extraterrestrial life.  

PubMed

Abstract In 1965, James Lovelock published a general statement, based on thermodynamic chemical equilibrium principles, about how to detect extant or extinct life on a planet other than Earth. Nearly 50 years later, it is possible to make such measurements with robotic missions such as current and future Mars rovers, and probes to sample icy plumes of Enceladus or Europa. We make a specific recommendation that certain characteristic patterns in the composition of lipid hydrocarbons can only result from a biological process, because the signal arises from a universal requirement related to lipid bilayer fluidity and membrane stability. Furthermore, the pattern can be preserved over millions of years, and instrumentation is already available to be incorporated into flight missions. Key Words: Biomarkers-Lipids-Biomembranes-Hydrocarbons-Extraterrestrial life. Astrobiology 14, 541-549. PMID:24735484

Georgiou, Christos D; Deamer, David W

2014-06-01

306

Nanostructure of Cationic Lipid-Oligonucleotide Complexes  

PubMed Central

Complexes (lipoplexes) between cationic liposomes and single-strand oligodeoxynucleotides (ODN) are potential delivery systems for antisense therapy. The nanometer-scale morphology of these assemblies is relevant to their transfection efficiency. In this work the monocationic lipid dioleoyloxytrimethylammoniumpropane, the neutral “helper” lipid cholesterol, and an 18-mer anti-bcl2 ODN were combined at different ratios. The lipoplexes formed were characterized for the quantity of ODN bound, for the degree of lipid mixing, and for their size. The nanostructure of the system was examined by cryogenic-temperature transmission electron microscopy, augmented by small-angle x-ray scattering. Addition of ODN to cationic liposomes induced both liposome aggregation and the formation of a novel condensed lamellar phase. This phase is proposed to be stabilized by anionic single-strand ODN molecules intercalated between cationic bilayers. The proportion of cholesterol present apparently did not affect the nature of lipoplex microstructure, but changed the interlamellar spacing.

Weisman, Sarah; Hirsch-Lerner, Danielle; Barenholz, Yechezkel; Talmon, Yeshayahu

2004-01-01

307

Interaction of small peptides with lipid bilayers.  

PubMed Central

Molecular dynamics simulations of the tripeptide Ala-Phe-Ala-O-tert-butyl interacting with dimyristoylphosphatidylcholine lipid bilayers have been carried out. The lipid and aqueous environments of the peptide, the alkyl chain order, and the lipid and peptide dynamics have been investigated with use of density profiles, radial distribution functions, alkyl chain order parameter profiles, and time correlation functions. It appears that the alkyl chain region accommodates the peptides in the bilayer with minimal perturbation to this region. The peptide dynamics in the bilayer bound form has been compared with that of the free peptide in water. The peptide structure does not vary on the simulation time scale (of the order of hundreds of picoseconds) compared with the solution structure in which a random structure is observed. Images FIGURE 4

Damodaran, K V; Merz, K M; Gaber, B P

1995-01-01

308

Lipid Corralling and Poloxamer Squeeze-Out in Membranes  

NASA Astrophysics Data System (ADS)

Using x-ray scattering measurements we have quantitatively determined the effect of poloxamer 188 (P188), a polymer known to seal damaged membranes, on the structure of lipid monolayers. P188 selectively inserts into low lipid-density regions of the membrane and “corrals” lipid molecules to pack tightly, leading to unexpected Bragg peaks at low nominal lipid density and inducing lipid/poloxamer phase separation. At tighter lipid packing, the once inserted P188 is squeezed out, allowing the poloxamer to gracefully exit when the membrane integrity is restored.

Wu, Guohui; Majewski, Jaroslaw; Ege, Canay; Kjaer, Kristian; Weygand, Markus Jan; Lee, Ka Yee

2004-07-01

309

Age and ethnic variations in sebaceous lipids  

PubMed Central

This study was conducted to compare lipid components of sebum from persons from three ethnic backgrounds—Caucasian, African American and Northern Asian. Men and women with no acne in two age groups (18?25 y and 35?45 y) were recruited. Skin surface hydration (SkiCon 200EX and NovaMeter), barrier function (Delfin VapoMeter), high-resolution clinical imaging, self-assessments and two pairs of sebutapes on the forehead that extracted the lipids on the surface of their skin were used. Significant differences (p < 0.05) in skin hydration between African Americans and Caucasians in both age groups were noted, with the order from highest to lowest absolute values: African American > Northern Asian > Caucasian. Transepidermal water loss (TEWL) measurements demonstrated that African Americans and Caucasians were significantly different (p < 0.05), with the trend being the inverse of the hydration trend—Caucasian > Northern Asian > African American, which would indicate better barrier function for African Americans with a lower TEWL. African American women had more total lipid production than Northern Asian or Caucasian women. When analyzing the three lipid classes (free fatty acids, triglycerides and wax esters), the trend became significant (p < 0.05) in the wax ester fraction when directly comparing African Americans with Caucasians. Additionally, six lipids were identified in the wax ester fractions that were significantly different in quantity (p < 0.05) between African Americans and Caucasians. These results identified significant differences in sebaceous lipid profiles across ethnic groups and determined that the differences correlated with skin barrier function.

Pappas, Apostolos; Fantasia, Jared; Chen, Theresa

2013-01-01

310

Lipid Rafts and Alzheimer's Disease: Protein-Lipid Interactions and Perturbation of Signaling  

PubMed Central

Lipid rafts are membrane domains, more ordered than the bulk membrane and enriched in cholesterol and sphingolipids. They represent a platform for protein-lipid and protein–protein interactions and for cellular signaling events. In addition to their normal functions, including membrane trafficking, ligand binding (including viruses), axonal development and maintenance of synaptic integrity, rafts have also been implicated in the pathogenesis of several neurodegenerative diseases including Alzheimer’s disease (AD). Lipid rafts promote interaction of the amyloid precursor protein (APP) with the secretase (BACE-1) responsible for generation of the amyloid ? peptide, A?. Rafts also regulate cholinergic signaling as well as acetylcholinesterase and A? interaction. In addition, such major lipid raft components as cholesterol and GM1 ganglioside have been directly implicated in pathogenesis of the disease. Perturbation of lipid raft integrity can also affect various signaling pathways leading to cellular death and AD. In this review, we discuss modulation of APP cleavage by lipid rafts and their components, while also looking at more recent findings on the role of lipid rafts in signaling events.

Hicks, David A.; Nalivaeva, Natalia N.; Turner, Anthony J.

2012-01-01

311

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

PubMed

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

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

2014-01-01

312

[Effect of melanins on lipid peroxidation].  

PubMed

Effects of melanins obtained from cultured Cladosporium cladosporidae fungi and Alpha grape on Fe(2+)-induced, Fe(2+)-ascorbate-induced, and NADPH-induced lipid peroxidation in rat liver, brain, and eye were studied. Melanins were shown to inhibit the accumulation of lipid peroxidation products in vitro. The inhibitory effects of melanins were not due to direct interactions of these pigments with superoxide anion (O2). However, melanins may interact with other free radicals. Melanins were demonstrated to have the ability to oxidize NADPH, which is probably one of the mechanisms of their antioxidant effects. PMID:11234396

Byshneva, L N; Senchuk, V V

2001-01-01

313

Lipid analysis of a ground sloth coprolite  

NASA Astrophysics Data System (ADS)

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

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

2009-09-01

314

Lipid membranes as solvents for carbon nanoparticles.  

PubMed

Fullerene is scarcely soluble in most solvents, including alkanes. Yet, it has been shown that C60 dissolves in lipid bilayers, whose interior is chemically identical to alkanes. Here, we use molecular simulations to explain why lipid bilayers are better than alkanes at dissolving fullerene clusters. Fullerene aggregation is driven by entropy, but enthalpic contributions determine the difference between alkanes and bilayers. Surprisingly, confinement and chain alignment in the bilayer do not affect fullerene aggregation, while solvent density and the perturbation of solvent-solvent interactions are key factors. PMID:24580709

Barnoud, Jonathan; Rossi, Giulia; Monticelli, Luca

2014-02-14

315

Adsorption of DNA onto anionic lipid surfaces.  

PubMed

Currently self-assembled DNA delivery systems composed of DNA multivalent cations and anionic lipids are considered to be promising tools for gene therapy. These systems become an alternative to traditional cationic lipid-DNA complexes because of their low cytotoxicity lipids. However, currently these nonviral gene delivery methods exhibit low transfection efficiencies. This feature is in large part due to the poorly understood DNA complexation mechanisms at the molecular level. It is well-known that the adsorption of DNA onto like charged lipid surfaces requires the presence of multivalent cations that act as bridges between DNA and anionic lipids. Unfortunately, the molecular mechanisms behind such adsorption phenomenon still remain unclear. Accordingly a historical background of experimental evidence related to adsorption and complexation of DNA onto anionic lipid surfaces mediated by different multivalent cations is firstly reviewed. Next, recent experiments aimed to characterise the interfacial adsorption of DNA onto a model anionic phospholipid monolayer mediated by Ca(2+) (including AFM images) are discussed. Afterwards, modelling studies of DNA adsorption onto charged surfaces are summarised before presenting preliminary results obtained from both CG and all-atomic MD computer simulations. Our results allow us to establish the optimal conditions for cation-mediated adsorption of DNA onto negatively charged surfaces. Moreover, atomistic simulations provide an excellent framework to understand the interaction between DNA and anionic lipids in the presence of divalent cations. Accordingly,our simulation results in conjunction go beyond the macroscopic picture in which DNA is stuck to anionic membranes by using multivalent cations that form glue layers between them. Structural aspects of the DNA adsorption and molecular binding between the different charged groups from DNA and lipids in the presence of divalent cations are reported in the last part of the study. Although this research work is far from biomedical applications, we truly believe that scientific advances in this line will assist, at least in part, in the rational design and development of optimal carrier systems for genes and applicable to other drugs. PMID:24359695

Martín-Molina, Alberto; Luque-Caballero, Germán; Faraudo, Jordi; Quesada-Pérez, Manuel; Maldonado-Valderrama, Julia

2014-04-01

316

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

317

Inclusion of the helper lipid dioleoyl-phosphatidylethanolamine in solid lipid nanoparticles inhibits their transfection efficiency.  

PubMed

Solid lipid nanoparticles (SLNs) are a promising system for the delivery of lipophilic and hydrophilic drugs. They consist of a solid lipid core that is stabilized by a layer of surfactants. By the incorporation of cationic lipids in the formulation, positively charged SLNs can be generated, that are suitable carriers for nucleic acids (DNA, siRNA). Considering the beneficial effect of helper lipids on the transfection efficiency with cationic liposomes, the effect of the helper lipid 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) on transfection with cationic lipid-containing solid lipid nanoparticles was investigated in PC3 prostate cancer cells. The inclusion of DOPE in SLN formulations, instead of promoted, strongly inhibited SLN transfection efficiency, by frustrating the accommodation of DNA by the particles, as was revealed by biochemical analysis. SLNs devoid of DOPE maintained a homogenous size distribution of approximately 150 nm following lipoplex assembly and cellular delivery, and showed transfection efficiency comparable to that of Lipofectamine 2000' (LF2k). Moreover, the SLNs maintain their high transfection efficiency after lyophilization and long-term storage (1-2 years), an important asset for biomedical applications. There is even the possibility to lyophilize the SLN carrier together with its DNA cargo, which represents an interesting pharmaceutical advantage of the SLN formulations over LF2k. These results reflect marked differences between the physicochemical properties of cationic liposomes and SLNs, the latter requiring more critical lipid-depending properties for effective 'packaging' of DNA but displaying a higher storage stability than cationic lipid based carriers like LF2k. PMID:24738343

de Jesus, Marcelo B; Radaic, Allan; Hinrichs, Wouter L J; Ferreira, Carmen V; de Paula, Eneida; Hoekstra, Dick; Zuhorn, Inge S

2014-02-01

318

An ER protein functionally couples neutral lipid metabolism on lipid droplets to membrane lipid synthesis in the ER.  

PubMed

Eukaryotic cells store neutral lipids such as triacylglycerol (TAG) in lipid droplets (LDs). Here, we have addressed how LDs are functionally linked to the endoplasmic reticulum (ER). We show that, in S. cerevisiae, LD growth is sustained by LD-localized enzymes. When LDs grow in early stationary phase, the diacylglycerol acyl-transferase Dga1p moves from the ER to LDs and is responsible for all TAG synthesis from diacylglycerol (DAG). During LD breakdown in early exponential phase, an ER membrane protein (Ice2p) facilitates TAG utilization for membrane-lipid synthesis. Ice2p has a cytosolic domain with affinity for LDs and is required for the efficient utilization of LD-derived DAG in the ER. Ice2p breaks a futile cycle on LDs between TAG degradation and synthesis, promoting the rapid relocalization of Dga1p to the ER. Our results show that Ice2p functionally links LDs with the ER and explain how cells switch neutral lipid metabolism from storage to consumption. PMID:24373967

Markgraf, Daniel F; Klemm, Robin W; Junker, Mirco; Hannibal-Bach, Hans K; Ejsing, Christer S; Rapoport, Tom A

2014-01-16

319

Effects of Dietary Lipids on Growth Food Conversion Lipid and Fatty Acid Composition of Channel Catfish  

Microsoft Academic Search

ABSTRACT,Channel,catfish (Ictalurus punctatus},fingerlings,were,reared in 1-m-diameter fiberglass tanks,at 26°and,fed 27 experimental,diets differing in source,of lipid. Duplicate groups,of fish were,fed each,of eight primary,lipid sources,and,each,lipid was,fed,at a level of 10% of diets in three molecular forms: triglycéride,free fatty acid, and ethyl ester. Highest average weights occurred when the fish were supplemented with beef tallow, olive oil and men haden,oil triglycérides.Substantially,lower,gains,were,obtained,from,groups fed short- and

Robert R. Stickney; James W. Andrews

320

Determination of oleamide and erucamide in polyethylene films by pressurised fluid extraction and gas chromatography  

Microsoft Academic Search

A pressurized fluid extraction (PFE) and gas chromatography-flame ionization detection (GC-FID) method is proposed to determine the slip agents in polyethylene (PE) films. The study of PFE variables was performed using a fractional factorial design (FFD) for screening and a central composite design (CCD) for optimizing the main variables obtained from the Pareto charts. The variables that were studied include

Álvaro Garrido-López; Vanesa Esquiu; María Teresa Tena

2006-01-01

321

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

1971-01-01

322

Fluorescopic evaluation of protein-lipid relations in cellular signalling  

Microsoft Academic Search

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

E. H. W. Pap

1994-01-01

323

Near infrared Raman spectra of human brain lipids.  

PubMed

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. PMID:15820887

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

2005-05-01

324

Evaluation of Selected Lipid Methods for Normalizing Pollutant Bioaccumulation.  

National Technical Information Service (NTIS)

Current environmental models use organism lipid concentrations to estimate maximum pollutant bioaccumulation potentials. The collaborative study has shown that significantly different lipid concentrations (3.5x) are found when using common, but different,...

R. C. Randall H. Lee R. J. Ozretich J. L. Lake R. J. Pruell

1991-01-01

325

Comparative lipid composition of heterotrophically and autotrophically grown Sulfolobus acidocaldarius.  

PubMed Central

Complex lipids from the thermoacidophilic facultative autotroph Sulfolobus acidocaldarius, as well as a strictly autotrophic isolate, were compared between cells grown on yeast extract and elemental sulfur. Lipids from both organisms grown autotrophically were nearly identical. Each contained about 15% neutral lipids, 35% glycolipids, and 50% acidic lipids. Glycolipids and acidic lipids contained C40H82-76-derived glycerol ether residues. Major glycolipids included the glycerol ether analogues of glucosyl galactosyl diglyceride (5%) and glucosyl polyol diglyceride (75%). Acidic lipids were comprised mainly of the glycerol ether analogues of phosphatidyl inositol (7%), inositolphosphoryl glucosyl polyol diglyceride (72%), and a partially characterized sulfate- and phosphate-containing derivative of glucosyl polyol diglyceride (13%). The lipids from cells grown heterotrophically were similar to those from autotrophically grown cells, except that the partially characterized acidic lipid was absent. In addition, the two glycolipids as well as the respective inositolphosphoryl derivatives were each present in nearly equal proportions. Images

Langworthy, T A

1977-01-01

326

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.

2002-01-01

327

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

2011-01-01

328

Drugs and Experimental Conditions Affecteing Lipid Transport and Deposition.  

National Technical Information Service (NTIS)

The effect of drugs affecting lipid mobilization (nicotinic acid) and transport (glucagon) are investigated in vitro and in vivo. The interactions with the nervous and hormonal control of lipid transport and particularly with the sympathetic system and pr...

R. Paoletti

1967-01-01

329

Irregular bilayer structure in vesicles prepared from Halobacterium cutirubrum lipids  

NASA Technical Reports Server (NTRS)

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

Lanyi, J. K.

1974-01-01

330

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

1971-01-01

331

Ultrastructural and Flow Cytometric Analyses of Lipid Accumulation in Microalgae.  

National Technical Information Service (NTIS)

Lipid accumulation in three species of microalgae was investigated with flow cytometry (FCM) and transmission electron microscopy (TEM). Previous studies using batch cultures of a algae have led to the assumption that lipid accumulation in microalgae is a...

J. A. Solomon R. E. Hand R. C. Mann

1986-01-01

332

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.

2012-01-01

333

Molecular dynamics simulations of lipid membrane electroporation.  

PubMed

The permeability of cell membranes can be transiently increased following the application of external electric fields. Theoretical approaches such as molecular modeling provide a significant insight into the processes affecting, at the molecular level, the integrity of lipid cell membranes when these are subject to voltage gradients under similar conditions as those used in experiments. This article reports on the progress made so far using such simulations to model membrane-lipid bilayer-electroporation. We first describe the methods devised to perform in silico experiments of membranes subject to nanosecond, megavolt-per-meter pulsed electric fields and of membranes subject to charge imbalance, mimicking therefore the application of low-voltage, long-duration pulses. We show then that, at the molecular level, the two types of pulses produce similar effects: provided the TM voltage these pulses create are higher than a certain threshold, hydrophilic pores stabilized by the membrane lipid headgroups form within the nanosecond time scale across the lipid core. Similarly, when the pulses are switched off, the pores collapse (close) within similar time scales. It is shown that for similar TM voltages applied, both methods induce similar electric field distributions within the membrane core. The cascade of events following the application of the pulses, and taking place at the membrane, is a direct consequence of such an electric field distribution. PMID:22644388

Delemotte, Lucie; Tarek, Mounir

2012-09-01

334

Compartmentalization of proteins in lipid droplet biogenesis  

Microsoft Academic Search

Our existing understanding of the structure, protein organization and biogenesis of the lipid droplet has relied heavily on microscopical techniques that lack resolution and the ability to preserve native cellular and protein composition. The electron microscopic technique of freeze-fracture replica immunogold labeling (FRIL) overcomes these problems, and is currently providing new perspectives in the field. Because of the property of

Horst Robenek; Insa Buers; Oliver Hofnagel; Mirko J. Robenek; David Troyer; Nicholas J. Severs

2009-01-01

335

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

2006-01-01

336

Lipid accumulation in dysferlin-deficient muscles.  

PubMed

Dysferlin is a membrane associated protein involved in vesicle trafficking and fusion. Defects in dysferlin result in limb-girdle muscular dystrophy type 2B and Miyoshi myopathy in humans and myopathy in A/J(dys-/-) and BLAJ mice, but the pathomechanism of the myopathy is not understood. Oil Red O staining showed many lipid droplets within the psoas and quadriceps muscles of dysferlin-deficient A/J(dys-/-) mice aged 8 and 12 months, and lipid droplets were also conspicuous within human myofibers from patients with dysferlinopathy (but not other myopathies). Electron microscopy of 8-month-old A/J(dys-/-) psoas muscles confirmed lipid droplets within myofibers and showed disturbed architecture of myofibers. In addition, the presence of many adipocytes was confirmed, and a possible role for dysferlin in adipocytes is suggested. Increased expression of mRNA for a gene involved in early lipogenesis, CCAAT/enhancer binding protein-?, in 3-month-old A/J(dys-/-) quadriceps (before marked histopathology is evident), indicates early induction of lipogenesis/adipogenesis within dysferlin-deficient muscles. Similar results were seen for dysferlin-deficient BLAJ mice. These novel observations of conspicuous intermyofibrillar lipid and progressive adipocyte replacement in dysferlin-deficient muscles present a new focus for investigating the mechanisms that result in the progressive decline of muscle function in dysferlinopathies. PMID:24685690

Grounds, Miranda D; Terrill, Jessica R; Radley-Crabb, Hannah G; Robertson, Terry; Papadimitriou, John; Spuler, Simone; Shavlakadze, Tea

2014-06-01

337

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

2005-01-01

338

Surface-mitigated lipid organization and dynamics  

Microsoft Academic Search

Supported bilayers, fluid phospholipid films of molecular thicknesses, have been of considerable interest as model biological membranes both for fundamental studies of cell surface mechanisms and for designing biosensors and assays for membrane-targets. Beyond biology, interfacial organization of amphiphiles and lipids into a discrete number of molecular layers provides arguably one of the most pristine experimental realizations of a self-organized,

Babak Sanii

2008-01-01

339

Lipids in Liver Disease: Looking Beyond Steatosis  

PubMed Central

See “Alterations in lipid metabolism mediate inflammation, fibrosis, and proliferation in a mouse model of chronic cholestatic liver injury,” by Moustafa T, Fickert P, Magnes C, et al, on page 140; and “A high-cholesterol diet exacerbates liver fibrosis in mice via accumulation of free cholesterol in hepatic stellate cells,” by Teratani T, Tomita K, Suzuki T, et al, on page 152.

SCHWABE, ROBERT F.; MAHER, JACQUELYN J.

2014-01-01

340

Self-assembly models for lipid mixtures  

NASA Astrophysics Data System (ADS)

Solutions of mixed long and short (detergent-like) phospholipids referred to as ``bicelle'' mixtures in the literature, are known to form a variety of different morphologies based on their total lipid composition and temperature in a complex phase diagram. Some of these morphologies have been found to orient in a magnetic field, and consequently bicelle mixtures are widely used to study the structure of soluble as well as membrane embedded proteins using NMR. In this work, we report on the low temperature phase of the DMPC and DHPC bicelle mixture, where there is agreement on the discoid structures but where molecular packing models are still being contested. The most widely accepted packing arrangement, first proposed by Vold and Prosser had the lipids completely segregated in the disk: DHPC in the rim and DMPC in the disk. Using data from small angle neutron scattering (SANS) experiments, we show how radius of the planar domain of the disks is governed by the effective molar ratio qeff of lipids in aggregate and not the molar ratio q (q = [DMPC]/[DHPC] ) as has been understood previously. We propose a new quantitative (packing) model and show that in this self assembly scheme, qeff is the real determinant of disk sizes. Based on qeff , a master equation can then scale the radii of disks from mixtures with varying q and total lipid concentration.

Singh, Divya; Porcar, Lionel; Butler, Paul; Perez-Salas, Ursula

2006-03-01

341

Pearling of lipid vesicles induced by nanoparticles.  

PubMed

We show that cationic nanoparticles encapsulated within vesicles of phosphocholine lipid can induce pearling. The dynamic process occurs as two stages: formation of tubular protrusions followed by pearling instability. The breakup into individual vesicles can be controlled by nanoparticle concentration. PMID:19775107

Yu, Yan; Granick, Steve

2009-10-14

342

Solid lipid nanoparticles coated with silk fibroin  

Microsoft Academic Search

Solid lipid nanoparticles (SLNs) composed of stearic acid (SA) and ceramide (Cer) were prepared by an emulsification and solidification method using sodium lauryl sulfate (an anionic surfactant) as a stabilizer. And then, the SLN was coated with silk fibroin (SF) under an acidic condition by an electrostatic interaction. The size was tens of nanometers to hundreds of nanometers, and the

Teak Kwan Kwon; Kun Bin Lim; Jin-Chul Kim

2011-01-01

343

Relationship between lipids and aflatoxin biosynthesis  

Microsoft Academic Search

This paper describes the key role of lipids on fungal growth and of lipoperoxidation on the output of aflatoxin biosynthesis both ‘in vitro’ and ‘in vivo’. ‘In vitro’ BHA, BHT and cysteamine, depending their concentration, are capable of reducing or blocking aflatoxin output induced by lipoperoxides or halomethanes in cultures ofAspergillus flavus orA. parasiticus without affecting fungal growth. ‘In vivo’

C. Fanelli; A. A. Fabbri

1989-01-01

344

LIPID BIOMARKER ANALYSIS OF MARINE DINOFLAGELLATES  

EPA Science Inventory

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

345

Lipid metabolism and hyperlipidemia in dogs  

Microsoft Academic Search

Lipid metabolism in dogs can be divided into exogenous and endogenous pathways and exhibits some unique characteristics compared to other species. Hyperlipidemia is common in dogs, and can be either primary or secondary to other diseases. Secondary hyperlipidemia is the most common form and can be a result of endocrine disorders, pancreatitis, cholestasis, protein-losing nephropathy, obesity, and high fat diets.

Panagiotis G. Xenoulis; Jörg M. Steiner

2010-01-01

346

A Rainbow Coalition of Lipid Transcriptional Regulators  

PubMed Central

Summary Lipids are essential structural constituents of bacterial cell membranes and walls, and their biosynthetic pathways are stringently regulated at both biochemical and genetic levels. The recent surge of new information about transcriptional regulation of bacterial lipid metabolism is highlighted by two studies in this issue of Molecular Microbiology by Hugo Gramajo's research group, who add two transcription factors to the diverse repertoire of lipid biosynthesis regulators. FasR is a Streptomyces coelicolor transcriptional activator of genes in fatty acid synthesis, which supplies substrates for membrane phospholipid and triglyceride storage droplets. MabR is a regulator in Mycobacterium tuberculosis that functions as a repressor of essential genes in the cell wall mycolic acid biosynthetic pathway. MabR also affects the expression of fas, which encodes the multifunctional fatty acid synthase that supports phospholipid and triglyceride synthesis. Despite belonging to the same protein family, the distinct ligand binding domains of FasR and MabR suggest different ligands may regulate their DNA binding. The characterization of FasR/MabR exemplifies the structural and functional diversity of the rainbow coalition of lipid transcriptional regulators that reflects the diverse life styles of bacteria.

Zhang, Yong-Mei; Rock, Charles O.

2010-01-01

347

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

1998-01-01

348

Turkish Heart Study: lipids, lipoproteins, and apolipoproteins  

Microsoft Academic Search

We examined the plasma lipids, lipoproteins, and selected apolipoproteins in approximately 9,000 men and women from six different regions of Turkey with markedly different diets, ranging from an Aegean coast diet high in olive oil (plasma cholesteryl ester fatty acids enriched in monounsatu- rated fatty acids) to an inland Anatolian diet high in meat and dairy products (plasma cholesteryl esters

Robert W. Mahley; K. Erhan Palaogiu; Judy Dawaon-Pepin; Anne-Marie Langlois; Vivian Cheung; Hiilya Onat; Patrick Fulks; Linda L. Mahley; Sinan Ozbayrakq; Oryal Giikdemir; Warren Winklers

349

Lipid droplet targeting domains of adipophilin  

Microsoft Academic Search

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

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

2003-01-01

350

Drug interactions of lipid-altering drugs.  

PubMed

The use of lipid-altering drugs has been shown to reduce the progression of atherosclerotic lesions and reduce the risk of atherosclerotic events (such as myocardial infarction and stroke). In general, these lipid-altering drugs are well tolerated but there is the potential for drug interactions. For example, HMG-CoA reductase inhibitors may interact with macrolides, azalides, azole antifungals and cyclosporin. Resins (such as cholestyramine and colestipol) may impair the absorption of many concurrent medications. Fibrates have potential drug interactions with warfarin, furosemide (frusemide), oral hypoglycaemics and probenecid. Nicotinic acid (niacin) may have potential drug interactions with high dose aspirin (acetylsalicylic acid), uricosuric agents (such as sulfapyrazone) and alcohol (ethanol). Finally, probucol may have potential drug interactions with antidysrhythmics, tricyclic antidepressants and phenothiazines. In addition, lipid-altering drugs, used in combination, may have the potential for drug interactions, enhancing some of the risks of adverse effects, such as myositis and hepatotoxicity. Therefore, in order to use lipid-altering drugs in the most effective, and safest manner, it is important for the clinician to have an understanding of the mechanisms of potential drug interactions, which drug interactions may theoretically occur, and specifically, which spe cific drug interactions have already been described. PMID:9825949

Bays, H E; Dujovne, C A

1998-11-01

351

Engineering lipid bilayer membranes for protein studies.  

PubMed

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

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

2013-01-01

352

Diffusion in Single Supported Lipid Bilayers  

NASA Astrophysics Data System (ADS)

Despite their potential relevance for the development of functionalized surfaces and biosensors, the study of single supported membranes using neutron scattering has been limited by the challenge of obtaining relevant dynamic information from a sample with minimal material. Using state of the art neutron instrumentation we have, for the first time, modeled lipid diffusion in single supported lipid bilayers.ootnotetextC.L. Armstrong, M.D. Kaye, M. Zamponi, E. Mamontov, M. Tyagi, T. Jenkins and M.C. Rheinst"adter, Soft Matter Communication, 2010, Advance Article, DOI: 10.1039/C0SM00637H While we find that the diffusion coefficient for the single bilayer system is comparable to a multi-lamellar lipid system, the molecular mechanism for lipid motion in the single bilayer is a continuous diffusion process with no sign of the flow-like ballistic motion reported in the stacked membrane system. In the future, these membranes will be used to hold and align proteins, mimicking physiological conditions enabling the study of protein structure, function and interactions in relevant and highly topical membrane/protein systems with minimal sample material.

Armstrong, C. L.; Trapp, M.; Rheinstädter, M. C.

2011-03-01

353

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

1989-01-01

354

Basic Biological SciencesLipids of Supragingival Calculus  

Microsoft Academic Search

The matrix of supragingival calculus constitutes 15.7% of the calculus dry weight and contains 54.9% protein and 10.2% lipids. Of the total lipids, 61.8% are represented by neutral lipids, 28% by glycolipids, and 10.2% by phospholipids. The neutral lipids exhibit a high content of free fatty acids (63.9%) and triglycerides (15.8%). The glycolipids are comprised of simple glycosphingolipids (17.2%), mainly

B. L. Slomiany; V. L. N. Murty; M. Aono; J. Sarosiek; A. Slomiany; I. D. Mandel

1983-01-01

355

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)

2002-05-03

356

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

2005-12-01

357

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

2013-01-01

358

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

PubMed

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

2013-01-01

359

LipidBlast in silico tandem mass spectrometry database for lipid identification.  

PubMed

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

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

2013-08-01

360

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

1994-01-01

361

Lipid-lipid interactions in reconstituted high-density lipoproteins by deuterium nuclear magnetic resonance  

Microsoft Academic Search

Lipid-lipid interactions between the core and monolayer have been studied by using reconstituted high-density lipoproteins (rHDLs) composed of apoHDLâ with either dipalmitoylphosphatidylcholine (DPPC) or egg phosphatidylcholine (egg PC) as the monolayer and either cholesteryl oleate (CO) or triolein (TO) as the core. The effect of the monolayer on the core was observed by deuterium nuclear magnetic resonance (²H NMR) studies

David B. Fenske; Yashpal I. Parmar; W. Dale Treleaven; Ravinder S. Chana; Robert J. Cushley

1988-01-01

362

Lipid interaction of Pseudomonas aeruginosa exotoxin A. Acid-triggered permeabilization and aggregation of lipid vesicles.  

PubMed Central

We have investigated the interaction of Pseudomonas exotoxin A with small unilamellar vesicles comprised of different phospholipids as a function of pH, toxin, and lipid concentration. We have found that this toxin induces vesicle permeabilization, as measured by the release of a fluorescent dye. Permeabilization is due to the formation of ion-conductive channels which we have directly observed in planar lipid bilayers. The toxin also produces vesicle aggregation, as indicated by an increase of the turbidity. Aggregation and permeabilization have completely different time course and extent upon toxin dose and lipid composition, thus suggesting that they are two independent events. Both time constants decrease by lowering the pH of the bulk phase or by introducing a negative lipid into the vesicles. Our results indicate that at least three steps are involved in the interaction of Pseudomonas exotoxin A with lipid vesicles. After protonation of one charged group the toxin becomes competent to bind to the surface of the vesicles. Binding is probably initiated by an electrostatic interaction because it is absolutely dependent on the presence of acidic phospholipids. Binding is a prerequisite for the subsequent insertion of the toxin into the lipid bilayer, with a special preference for phosphatidylglycerol-containing membranes, to form ionic channels. At high toxin and vesicle concentrations, bound toxin may also induce aggregation of the vesicles, particularly when phosphatidic acid is present in the lipid mixture. A quenching of the intrinsic tryptophan fluorescence of the protein, which is induced by lowering the pH of the solution, becomes more drastic in the presence of lipid vesicles. However, this further quenching takes so long that it cannot be a prerequisite to either vesicle permeabilization or aggregation. Pseudomonas exotoxin A shares many of these properties with other bacterial toxins like diphtheria and tetanus toxin. Images FIGURE 7 FIGURE 8 FIGURE 12

Menestrina, G; Pederzolli, C; Forti, S; Gambale, F

1991-01-01

363

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

PubMed

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

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

2014-06-26

364

Intrafamilial Associations of Lipid Profiles and the Role of Nutrition: The Tehran Lipid and Glucose Study  

Microsoft Academic Search

Background: The role of gene and environment in the genesis of abnormal lipid profile is still a controversial issue. Objective: To clarify the importance of certain parental risk factors associated with lipid profiles of children and adolescents. Methods: We conducted this cross-sectional population-based study in district 13 in the east of metropolitan Tehran.One hundred and thirteen eligible families comprising 455

Parvin Mirmiran; Mohammadreza Mirbolooki; Peimaneh Heydarian; Payam Salehi; Fereidoun Azizi

2008-01-01

365

Serum lipid levels in an Iranian population of children and adolescents: Tehran lipid and glucose study  

Microsoft Academic Search

Data from 3148 participants aged 3–19years (1447 males and 1701 females) in the cross-sectional phase of Tehran lipid and glucose study (February 1999–May 2000) were used to determine serum lipid levels [total cholesterol (TC), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)] after 12–14 hours overnight fast. The values were analyzed by sex and age. Mean serum

F. Azizi; M. Rahmani; M. Madjid; S. Allahverdian; J. Ghanbili; A. Ghanbarian; R. Hajipour

2001-01-01

366

Serum lipid levels in an Iranian adults population: Tehran lipid and glucose study  

Microsoft Academic Search

Data from 6246 participants aged 20–64 years (2339 males and 3907 females) in the cross-sectional phase of Tehran Lipid and Glucose Study (February 1999–May 2000) were used to determine distribution of serum lipid levels after 12–14 hour overnight fast. Mean total cholesterol (TC) concentration was 210 mg\\/dl. TC was significantly greater in females than males, 213 and 206 mg\\/dl, respectively

F. Azizi; M. Rahmani; A. Ghanbarian; H. Emami; P. Salehi; P. Mirmiran; N. Sarbazi

2003-01-01

367

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

2004-01-01

368

Lipid provisioning of turtle eggs and hatchlings: total lipid, phospholipid, triacylglycerol and triacylglycerol fatty acids  

Microsoft Academic Search

Lipid composition of eggs and hatchlings was studied in painted, snapping and Blanding's turtles from western Nebraska. The average total lipid proportions of the egg yolk, post-embryonic yolk and hatchling soma dry masses were high in painted turtles (29.80%, 42.16% and 14.18%, respectively) relative to snapping and Blanding's turtles (egg yolk <14%, postembryonic yolk <17%, hatchling soma <2%). The proportion

John W. Rowe; Lisa Holy; Royce E. Ballinger; David Stanley-Samuelson

1995-01-01

369

Lipid rafts and their roles in T-cell activation.  

PubMed

Lipid rafts are defined as detergent-resistant membrane microdomains of specific lipid and protein composition. They are involved in many aspects of cell biology, including T-cell activation and immunoreceptor signaling. This review discusses current controversies around lipid rafts and summarizes recent developments in the area. PMID:15715974

Horejsí, Václav

2005-02-01

370

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

371

Targeting proteins to membranes, using signal sequences for lipid modifications.  

PubMed

Changing an existing lipid or appending a lipid to a cytosolic protein has emerged as an important technique for targeting proteins to membranes and for constitutively activating the membrane-bound protein. The potential for more precise or regulated interactions of lipidated proteins in membrane subdomains suggests that this method for membrane targeting will be of increasing usefulness. PMID:11305118

Stickney, J T; Booden, M A; Buss, J E

2001-01-01

372

Mitochondrial free radical production induces lipid peroxidation during myohemoglobinuria  

Microsoft Academic Search

Mitochondrial free radical production induces lipid peroxidation during myohemoglobinuria. Iron catalyzed free radical formation and lipid peroxidation are accepted mechanisms of heme protein-induced acute renal failure. However, the source(s) of those free radicals which trigger lipid peroxidation in proximal tubular cells remains unknown. This study tested the potential involvement of mitochondrial electron transport, xanthine oxidase activity, and arachidonic acid metabolism

Richard A Zager

1996-01-01

373

Adsorption of lysozyme to phospholipid and meibomian lipid monolayer films  

Microsoft Academic Search

It is believed that a lipid layer forms the outer layer of the pre-ocular tear film and this layer helps maintain tear film stability by lowering its surface tension. Proteins of the aqueous layer of the tear film (beneath the lipid layer) may also contribute to reducing surface tension by adsorbing to, or penetrating the lipid layer. The purpose of

Poonam Mudgil; Margaux Torres; Thomas J. Millar

2006-01-01

374

Adsorption of Human Tear Lipocalin to Human Meibomian Lipid Films  

Microsoft Academic Search

PURPOSE. Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. METHODS. Tlc was purified from

Thomas J. Millar; Poonam Mudgil; Igor A. Butovich; Chendur K. Palaniappan

2009-01-01

375

Optimization of Physiological Lipid Mixtures for Barrier Repair  

Microsoft Academic Search

Three stratum corneum lipids, ceramides, cholesterol (CHOL), and free fatty acids (FA), are required for permeability barrier homeostasis. Recent studies have shown that application of one or two of these lipids to perturbed skin delays barrier recovery; only equimolar mixtures allow normal recovery. We asked here whether any physiological lipid mixtures improve barrier repair, as assessed by transepidermal water loss.

Man Mao-Qiang; Kenneth R. Feingold; Carl R. Thornfeldt; Peter M. Elias

1996-01-01

376

The effect of lipids, with and without humectant, on  

Microsoft Academic Search

Specialized lipids found in the stratum corneum, namely ceramides, have been shown to have beneficial skin properties due to their lipid bilayer-forming potential in the presence of cholesterol and fatty acids. We were interested in determining whether other bilayer-forming lipids, such as phospholipids, could deliver similar benefits and how these benefits compare with common moisturizer ingredients such as petrolatum and

ROBERT S. SUMMERS; BEVERLY SUMMERS; PREM CHANDAR; CAROL FEINBERG; RICHARD GURSKY; ANTHONY V. RAWLINGS

377

The inner side of T cell lipid rafts  

Microsoft Academic Search

A key question in understanding the functional role of lipid rafts is whether lipid microdomains at the plasma membrane outer leaflet are coupled to lipid microdomains at the inner leaflet. By using a cyan-fluorescent protein (CFP) targeted to inner plasma membrane rafts of Jurkat T cells, we found that raft domains at the outer and inner leaflets are physically coupled

Giorgia Gri; Barbara Molon; Santos Manes; Tullio Pozzan; Antonella Viola

2004-01-01

378

Solid lipid nanoparticles for targeted brain drug delivery  

Microsoft Academic Search

The present review discusses the potential use of solid lipid nanoparticles for brain drug targeting purposes. The state of the art on surfactant-coated poly(alkylcyanoacrylate) nanoparticles specifically designed for brain targeting is given by emphasizing the transfer of this technology to solid lipid matrices. The available literature on solid lipid nanoparticles and related carriers for brain drug targeting is revised as

Paolo Blasi; Stefano Giovagnoli; Aurélie Schoubben; Maurizio Ricci; Carlo Rossi

2007-01-01

379

Lipid Layer-based Corrosion Monitoring on Metal Substrates.  

National Technical Information Service (NTIS)

The purpose of this research is to explore lipid layers as a potential biosensor for corrosion. It is hypothesized that applying a lipid layer to metals will allow for corrosion monitoring by measuring lipid degradation as a response to oxidation of the m...

A. Ghoshal D. Cole J. Ayers S. Kinlein

2013-01-01

380

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.

1984-01-01

381

Human stratum corneum lipids: characterization and regional variations  

Microsoft Academic Search

The lipids of mammalian stratum corneum are known to be important regulators of skin permeability. Since the human stratum corneum displays remarkable regional variations in skin permeability, we assessed the total lipid con- centration, the distribution of all major lipid species, and the fatty acid composition in Bligh-Dyer extracts from four skin sites (abdomen, leg, face, and sole) that are

Marilyn A. Lampe; A. L. Burlingame; JoAnne Whitney; Mary L. Williams; Barbara E. Brown; Esther Roitman; Peter M. Elias

382

Docosahexaenoic acid selectively inhibits plasma membrane targeting of lipidated proteins  

Microsoft Academic Search

Membrane localization of lipidated cytosolic signaling proteins is mediated by interactions between specific lipid anchors and membranes, but little is known about the regulatory role of membrane composition in lipidated protein membrane targeting. Here, using green fluorescent protein (GFP) chimeras and quantitative fluorescence microscopy in living mouse colonocytes, we show that docosahexaenoic acid (DHA), a dietary polyunsaturated fatty acid (PUFA)

Jeongmin Seo; Rola Barhoumi; Arthur E. Johnson; Joanne R. Lupton; Robert S. Chapkin

2006-01-01

383

The removal of water and nonlipid contaminants from lipid extracts  

Microsoft Academic Search

A technique is presented for the removal of water and water-soluble non-lipid contaminants from lipid extracts. The process\\u000a is quicker and simpler than existing techniques and lipid recoveries of greater than 97% have been obtained.

J. P. Williams; P. A. Merrilees

1970-01-01

384

Characterization of lipids in wheat grain as probed by microspectrofluorometry  

Microsoft Academic Search

The baking quality and storage stability of white flour are affected by its non-starch lipids content, and by the proportions of non-polar and polar lipids classes. At present, information on the lipids composition in the various parts of the wheat grain is scarce and their redistribution in the flour millstreams after milling is not well understood. Here we have implemented

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

1999-01-01

385

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

2010-01-01

386

Asymmetric Supported Lipid Bilayer Formation via Methyl-?-Cyclodextrin Mediated Lipid Exchange: Influence of Asymmetry on Lipid Dynamics and Phase Behavior.  

PubMed

Supported lipid bilayers (SLBs) are broadly used as minimal membrane models and commonly produced by vesicle fusion (VF) on solid supports. Despite its advantages, VF does not allow the controlled formation of bilayers that mimic the leaflet asymmetry in lipid composition normally found in biological systems. Here we present a simple, quick, and versatile method to produce SLBs with a desired asymmetric lipid composition which is stable for ca. 4 h. We apply methyl-?-cyclodextrin mediated lipid exchange to SLBs formed by VF to enrich the upper leaflet of the bilayer with sphingomyelin. The bilayer asymmetry is assessed by fluorescence correlation spectroscopy, measuring the lipid mobility separately in each leaflet. To check the compatibility of the method with the most common protein reconstitution approaches, we report the production of asymmetric SLBs (aSLBs) in the presence of a glycosylphosphatidylinositol-anchored protein, reconstituted in the bilayer both, via direct protein insertion, and via proteoliposomes fusion. We finally apply aSLBs to study phase separation and transbilayer lipid movement of raft-mimicking lipid mixtures. The observed differences in terms of phase separation in symmetric and asymmetric SLBs with the same overall lipid composition provide further experimental evidence that the transversal lipid distribution affects the overall lipid miscibility and allow to temporally investigate leaflet mixing. PMID:24885372

Visco, Ilaria; Chiantia, Salvatore; Schwille, Petra

2014-07-01

387

GLUT4 glucose transporter deficiency increases hepatic lipid production and peripheral lipid utilization  

PubMed Central

A critical defect in type 2 diabetes is impaired insulin-stimulated glucose transport and metabolism in muscle and adipocytes. To understand the metabolic adaptations this elicits, we generated mice with targeted disruption of the GLUT4 glucose transporter in both adipocytes and muscle (AMG4KO). In contrast to total body GLUT4-null mice, AMG4KO mice exhibit normal growth, development, adipose mass, and longevity. They develop fasting hyperglycemia and glucose intolerance and are at risk for greater insulin resistance than mice lacking GLUT4 in only one tissue. Hyperinsulinemic-euglycemic clamp studies showed a 75% decrease in glucose infusion rate and markedly reduced 2-deoxyglucose uptake into skeletal muscle (85–90%) and white adipose tissue (65%). However, AMG4KO mice adapt by preferentially utilizing lipid fuels, as evidenced by a lower respiratory quotient and increased clearance of lipids from serum after oral lipid gavage. While insulin action on hepatic glucose production and gluconeogenic enzymes is impaired, hepatic glucokinase expression, incorporation of 14C-glucose into lipids, and hepatic VLDL-triglyceride release are increased. The lipogenic activity may be mediated by increased hepatic expression of SREBP-1c and acetyl-CoA carboxylase. Thus, inter-tissue communication results in adaptations to impaired glucose transport in muscle and adipocytes that involve increased hepatic glucose uptake and lipid synthesis, while muscle adapts by preferentially utilizing lipid fuels. Genetic determinants limiting this “metabolic flexibility” may contribute to insulin resistance and type 2 diabetes in humans.

Kotani, Ko; Peroni, Odile D.; Minokoshi, Yasuhiko; Boss, Olivier; Kahn, Barbara B.

2004-01-01

388

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

PubMed

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

2013-01-01

389

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

2013-01-01

390

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

PubMed

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

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

2014-04-15

391

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

PubMed

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

2011-03-01

392

Multiscale structures of lipids in foods as parameters affecting fatty acid bioavailability and lipid metabolism.  

PubMed

On a nutritional standpoint, lipids are now being studied beyond their energy content and fatty acid (FA) profiles. Dietary FA are building blocks of a huge diversity of more complex molecules such as triacylglycerols (TAG) and phospholipids (PL), themselves organised in supramolecular structures presenting different thermal behaviours. They are generally embedded in complex food matrixes. Recent reports have revealed that molecular and supramolecular structures of lipids and their liquid or solid state at the body temperature influence both the digestibility and metabolism of dietary FA. The aim of the present review is to highlight recent knowledge on the impact on FA digestion, absorption and metabolism of: (i) the intramolecular structure of TAG; (ii) the nature of the lipid molecules carrying FA; (iii) the supramolecular organization and physical state of lipids in native and formulated food products and (iv) the food matrix. Further work should be accomplished now to obtain a more reliable body of evidence and integrate these data in future dietary recommendations. Additionally, innovative lipid formulations in which the health beneficial effects of either native or recomposed structures of lipids will be taken into account can be foreseen. PMID:23624223

Michalski, M C; Genot, C; Gayet, C; Lopez, C; Fine, F; Joffre, F; Vendeuvre, J L; Bouvier, J; Chardigny, J M; Raynal-Ljutovac, K

2013-10-01

393

Intravenous fish oil lipid emulsion promotes a shift toward anti-inflammatory proresolving lipid mediators.  

PubMed

Parenteral nutrition (PN)-associated liver disease (PNALD) is a life-threatening complication of the administration of PN. The development of PNALD may be partly due to the composition of the lipid emulsion administered with PN: soybean oil-based lipid emulsions (SOLE) are associated with liver disease, while fish oil-based lipid emulsions (FOLE) are associated with prevention and improvement of liver disease. The objective of this study was to determine how the choice of lipid emulsion modified the production of bioactive lipid mediators (LMs). We utilized a mouse model of steatosis to study the differential effect of FOLE and SOLE. We subsequently validated these results in serum samples from a small cohort of human infants transitioning from SOLE to FOLE. In mice, FOLE was associated with production of anti-inflammatory, proresolving LMs; SOLE was associated with increased production of inflammatory LMs. In human infants, the transition from SOLE to FOLE was associated with a shift toward a proresolving lipidome. Together, these results demonstrate that the composition of the lipid emulsion directly modifies inflammatory homeostasis. PMID:24091595

Kalish, Brian T; Le, Hau D; Fitzgerald, Jonathan M; Wang, Samantha; Seamon, Kyle; Gura, Kathleen M; Gronert, Karsten; Puder, Mark

2013-12-01

394

Free Lipid A Isolated from Porphyromonas gingivalis Lipopolysaccharide Is Contaminated with Phosphorylated Dihydroceramide Lipids: Recovery in Diseased Dental Samples  

PubMed Central

Recent reports indicate that Porphyromonas gingivalis mediates alveolar bone loss or osteoclast modulation through engagement of Toll-like receptor 2 (TLR2), though the factors responsible for TLR2 engagement have yet to be determined. Lipopolysaccharide (LPS) and lipid A, lipoprotein, fimbriae, and phosphorylated dihydroceramides of P. gingivalis have been reported to activate host cell responses through engagement of TLR2. LPS and lipid A are the most controversial in this regard because conflicting evidence has been reported concerning the capacity of P. gingivalis LPS or lipid A to engage TLR2 versus TLR4. In the present study, we first prepared P. gingivalis LPS by the Tri-Reagent method and evaluated this isolate for contamination with phosphorylated dihydroceramide lipids. Next, the lipid A prepared from this LPS was evaluated for the presence of phosphorylated dihydroceramide lipids. Finally, we characterized the lipid A by the matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS) and electrospray-MS methods in order to quantify recovery of lipid A in lipid extracts from diseased teeth or subgingival plaque samples. Our results demonstrate that both the LPS and lipid A derived from P. gingivalis are contaminated with phosphorylated dihydroceramide lipids. Furthermore, the lipid extracts derived from diseased teeth or subgingival plaque do not contain free lipid A constituents of P. gingivalis but contain substantial amounts of phosphorylated dihydroceramide lipids. Therefore, the free lipid A of P. gingivalis is not present in measurable levels at periodontal disease sites. Our results also suggest that the TLR2 activation of host tissues attributed to LPS and lipid A of P. gingivalis could actually be mediated by phosphorylated dihydroceramides.

Bajrami, Bekim; Clark, Robert B.; Housley, William; Yao, Xudong

2012-01-01

395

Food intake and absorption are affected by dietary lipid level and lipid source in seabream ( Sparus aurata L.) larvae  

Microsoft Academic Search

Marine larval nutrition studies have classically focused on essential fatty acid (EFA) requirements and very little is known regarding the effect of total lipid level or lipid source on food ingestion and absorption, which are important factors determining growth. In the present work two experiments analysed food intake and nutrient absorption in seabream larvae in response to two dietary lipid

Sofia Morais; Michal Torten; Oryia Nixon; Sigal Lutzky; Luís E. C. Conceição; Maria Teresa Dinis; Amos Tandler; William Koven

2006-01-01

396

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.

2013-01-01

397

Lipid Peroxidation in Psychiatric Illness: Overview of Clinical Evidence  

PubMed Central

The brain is known to be sensitive to oxidative stress and lipid peroxidation. While lipid peroxidation has been shown to contribute to many disease processes, its role in psychiatric illness has not been investigated until recently. In this paper, we provide an overview of lipid peroxidation in the central nervous system as well as clinical data supporting a link between lipid peroxidation and disorders such as schizophrenia, bipolar disorder, and major depressive disorder. These data support further investigation of lipid peroxidation in the effort to uncover therapeutic targets and biomarkers of psychiatric disease.

Joshi, Yash B.; Pratico, Domenico

2014-01-01

398

The dependence of lipid asymmetry upon polar headgroup structure.  

PubMed

The effect of lipid headgroup structure upon the stability of lipid asymmetry was investigated. Using methyl-?-cyclodextrin -induced lipid exchange, sphingomyelin (SM) was introduced into the outer leaflets of lipid vesicles composed of phosphatidylglycerol, phosphatidylserine (PS), phosphatidylinositol, or cardiolipin, in mixtures of all of these lipids with phosphatidylethanolamine (PE), and in a phosphatidylcholine/phosphatidic acid mixture. Efficient SM exchange (>85% of that expected for complete replacement of the outer leaflet) was obtained for every lipid composition studied. Vesicles containing PE mixed with anionic lipids showed nearly complete asymmetry which did not decay after 1 day of incubation. However, vesicles containing anionic lipids without PE generally only exhibited partial asymmetry, which further decayed after 1 day of incubation. Vesicles containing the anionic lipid PS were an exception, showing nearly complete and stable asymmetry. It is likely that the combination of multiple charged groups on PE and PS inhibit transverse diffusion of these lipids across membranes relative to those lipids that only have one anionic group. Possible explanations of this behavior are discussed. The asymmetry properties of PE and PS may explain some of their functions in plasma membranes. PMID:24101657

Son, Mijin; London, Erwin

2013-12-01

399

Preparation of artificial plasma membrane mimicking vesicles with lipid asymmetry.  

PubMed

Lipid asymmetry, the difference in lipid distribution across the lipid bilayer, is one of the most important features of eukaryotic cellular membranes. However, commonly used model membrane vesicles cannot provide control of lipid distribution between inner and outer leaflets. We recently developed methods to prepare asymmetric model membrane vesicles, but facile incorporation of a highly controlled level of cholesterol was not possible. In this study, using hydroxypropyl-?-cyclodextrin based lipid exchange, a simple method was devised to prepare large unilamellar model membrane vesicles that closely resemble mammalian plasma membranes in terms of their lipid composition and asymmetry (sphingomyelin (SM) and/or phosphatidylcholine (PC) outside/phosphatidylethanolamine (PE) and phosphatidylserine (PS) inside), and in which cholesterol content can be readily varied between 0 and 50 mol%. We call these model membranes "artificial plasma membrane mimicking" ("PMm") vesicles. Asymmetry was confirmed by both chemical labeling and measurement of the amount of externally-exposed anionic lipid. These vesicles should be superior and more realistic model membranes for studies of lipid-lipid and lipid-protein interaction in a lipid environment that resembles that of mammalian plasma membranes. PMID:24489974

Lin, Qingqing; London, Erwin

2014-01-01

400

Lipid Composition of the Zoospores of Blastocladiella emersonii1  

PubMed Central

The zoospores of Blastocladiella emersonii, when derived from cultures grown on solid media, contain about 11% total lipid. This lipid was separated chromatographically on silicic acid into neutral lipid (46.6%), glycolipid (15.8%), and phospholipid (37.6%). Each class was fractionated further on columns of silicic acid, Florisil, or diethylaminoethyl-cellulose, and monitored by thin-layer chromatography. Triglycerides were the major neutral lipids, mono- and diglycosyldiglycerides were the major glycolipids, and phosphatidylcholine and phosphatidylethanolamine were the major phospholipids. Other neutral lipids and phospholipids detected were: hydrocarbons, free fatty acids, free sterols, sterol esters, diglycerides, monoglycerides, lysophosphatidylcholine, lysophosphatidylethanolamine, phosphatidic acid, phosphatidylserine, and phosphatidylinositol. Palmitic, palmitoleic, stearic, oleic, ?-linolenic, and arachidonic acids were the most frequently occurring fatty acids. When B. emersonii was grown in 14C-labeled liquid media, lipid again accounted for 11% of both mature plants and zoospores released from them. The composition of the lipid extracted from such plants and spores was also the same; however, it differed markedly from that of the lipid in spores harvested from solid media, consisting of 28.3% neutral lipid, 12.0% glycolipid, and 59.7% phospholipid. The major lipids were again triglycerides for neutral lipids, mono- and diglycosyldiglycerides for glycolipids, and phosphatidyl choline and phosphatidylethanolamine for phospholipids. Images

Mills, G. L.; Cantino, E. C.

1974-01-01

401

A systematic survey of lipids across mouse tissues.  

PubMed

Lipids are a diverse collection of macromolecules essential for normal physiology, but the tissue distribution and function for many individual lipid species remain unclear. Here, we report a mass spectrometry survey of lipid abundance across 18 mouse tissues, detecting ~1,000 mass spectrometry features, of which we identify 179 lipids from the glycerolipids, glycerophospholipids, lysophospholipids, acylcarnitines, sphingolipids, and cholesteryl ester classes. Our data reveal tissue-specific organization of lipids and can be used to generate testable hypotheses. For example, our data indicate that circulating triglycerides positively and negatively associated with future diabetes in humans are enriched in mouse adipose tissue and liver, respectively, raising hypotheses regarding the tissue origins of these diabetes-associated lipids. We also integrate our tissue lipid data with gene expression profiles to predict a number of substrates of lipid-metabolizing enzymes, highlighting choline phosphotransferases and sterol O-acyltransferases. Finally, we identify several tissue-specific lipids not present in plasma under normal conditions that may be of interest as biomarkers of tissue injury, and we show that two of these lipids are released into blood following ischemic brain injury in mice. This resource complements existing compendia of tissue gene expression and may be useful for integrative physiology and lipid biology. PMID:24518676

Jain, Mohit; Ngoy, Soeun; Sheth, Sunil A; Swanson, Raymond A; Rhee, Eugene P; Liao, Ronglih; Clish, Clary B; Mootha, Vamsi K; Nilsson, Roland

2014-04-15

402

Lipid raft: A floating island of death or survival  

SciTech Connect

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

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

2012-03-15

403

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

PubMed Central

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

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

1996-01-01

404

Salivary lipid profiles of the leech (Hirudo medicinalis).  

PubMed

Saliva was collected from sixteen leeches (Hirudo medicinalis). The saliva was analyzed for its total lipid content (3.26 +/- 0.31 mg of total lipids per 100 mL saliva). The lipids were separated into polar and nonpolar by chromatographic techniques. The neutral fraction was approximately 2/3 of the total, and the polar fraction was approximately 1/3 of the total lipids. Thin-layer chromatography was used to obtain the individual profiles of the polar and nonpolar lipids. Of the identified lipids, phosphatidic acids and free fatty acids represented the largest percentage. These results suggest that the leech contains a unique lipid distribution, and that some of these components may be potent phospholipases and lipases that probably are present in its saliva for the purpose of preventing plugging or healing of the wound in the attacked organism. PMID:8869892

Rabinowitz, J L

1996-08-01

405

Lipid accumulation and dendritic cell dysfunction in cancer  

PubMed Central

Professional antigen presenting cells, dendritic cells (DC) are responsible for initiation and maintenance of immune responses. Here, we report that a substantial proportion of DCs in tumor-bearing mice and cancer patients have increased levels of triglycerides. Lipid accumulation in DCs was caused by increased uptake of extracellular lipids due to up-regulation of scavenger receptor A. DCs with high lipid content were not able to effectively stimulate allogeneic T cells or present tumor-associated antigens. DCs with high and normal lipid levels did not differ in expression of MHC and co-stimulatory molecules. However, lipid-laden DCs had reduced capacity to process antigens. Pharmacological normalization of lipid levels in DCs with an inhibitor of acetyl-CoA carboxylase restored the functional activity of DCs and substantially enhanced the effects of a cancer vaccine. These findings support the regulation of immune responses in cancer by manipulation of lipid levels in DCs.

Herber, Donna L.; Cao, Wei; Nefedova, Yulia; Novitskiy, Sergey V.; Nagaraj, Srinivas; Tyurin, Vladimir A.; Corzo, Alex; Cho, Hyun Il; Celis, Esteban; Lennox, Briana; Knight, Stella C.; Padhya, Tapan; McCaffrey, Thomas V.; McCaffrey, Judith C.; Antonia, Scott; Fishman, Mayer; Ferris, Robert L.; Kagan, Valerian E.; Gabrilovich, Dmitry I.

2010-01-01

406

Lipids in cell biology: how can we understand them better?  

PubMed

Lipids are a major class of biological molecules and play many key roles in different processes. The diversity of lipids is on the same order of magnitude as that of proteins: cells express tens of thousands of different lipids and hundreds of proteins to regulate their metabolism and transport. Despite their clear importance and essential functions, lipids have not been as well studied as proteins. We discuss here some of the reasons why it has been challenging to study lipids and outline technological developments that are allowing us to begin lifting lipids out of their "Cinderella" status. We focus on recent advances in lipid identification, visualization, and investigation of their biophysics and perturbations and suggest that the field has sufficiently advanced to encourage broader investigation into these intriguing molecules. PMID:24925915

Muro, Eleonora; Atilla-Gokcumen, G Ekin; Eggert, Ulrike S

2014-06-15

407

Roles of the lipid metabolism in hepatic stellate cells activation ?.  

PubMed

The lipids present in hepatic stellate cells (HSCs) lipid droplets include retinyl ester, triglyceride, cholesteryl ester, cholesterol, phospholipids and free fatty acids. Activation of HSCs is crucial to the development of fibrosis in liver disease. During activation, HSCs transform into myofibroblasts with concomitant loss of their lipid droplets and production of excessive extracellular matrix. Release of lipid droplets containing retinyl esters and triglyceride is a defining feature of activated HSCs. Accumulating evidence supports the proposal that recovering the accumulation of lipids would inhibit the activation of HSCs. In healthy liver, quiescent HSCs store 80% of total liver retinols and release them depending on the extracellular retinol status. However, in injured liver activated HSCs lose their retinols and produce a considerable amount of extracellular matrix, subsequently leading to liver fibrosis. Further findings prove that lipid metabolism of HSCs is closely associated with its activation, yet relationship between activated HSCs and the lipid metabolism has remained mysterious. PMID:24382226

Jing, Xin-yan; Yang, Xue-feng; Qing, Kai; Ou-yang, Yan

2013-12-01

408

Hot-melt coating with lipid excipients.  

PubMed

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

2013-12-01

409

Membrane lipids and the origin of life  

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

410

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.

2012-01-01

411

Lipid transport in the lactating mammary gland.  

PubMed

Mammalian cells depend on phospholipid (PL) and fatty acid (FA) transport to maintain membrane structure and organization, and to fuel and regulate cellular functions. In mammary glands of lactating animals, copious milk secretion, including large quantities of lipid in some species, requires adaptation and integration of PL and FA synthesis and transport processes to meet secretion demands. At present few details exist about how these processes are regulated within the mammary gland. However, recent advances in our understanding of the structural and molecular biology of membrane systems and cellular lipid trafficking provide insights into the mechanisms underlying the regulation and integration of PL and FA transport processes the lactating mammary gland. This review discusses the PL and FA transport processes required to maintain the structural integrity and organization of the mammary gland and support its secretory functions within the context of current molecular and cellular models of their regulation. PMID:24567110

McManaman, James L

2014-03-01

412

Critical shape transitions of monolayer lipid domains  

PubMed Central

Fluorescence microscopy can be used to visualize coexisting fluid phases in lipid monolayers composed of cholesterol and dipalmitoyl phosphatidylcholine under specified conditions of temperature, composition, and lateral pressure. At a critical composition of ?30 mol% cholesterol, decreasing the average molecular area below ac [unk]50 Å2 per molecule forces the binary mixture through a critical point, where the monolayer becomes homogeneous. At molecular areas ?10% above this critical area, we observe shape transitions from liquid domains with circular shapes to domains with less symmetrical shapes. Shape transitions and critical shape fluctuations can also be triggered with light, due to photochemical effects on the monolayer. Shape fluctuations of lipid domains can thus be used to sense chemical events at the air-water interface. Images

Rice, Peter A.; McConnell, Harden M.

1989-01-01

413

SERUM LIPIDS : NEW BIOLOGICAL MARKERS IN DEPRESSION ?  

PubMed Central

Several studies suggest that a low cholesterol concentration is associated with depression. The authors sought to determine whether an association exists between serum lipid concentrations and depression. 28 drug-naive patients of major depression diagnosed according to DSMlll- R criteria were included in the study and severity of depression was measured on Hamilton Rating Scale for Depression. Suicidal intent was assessed on Suicidal Intent Questionnaire. 28 normal healthy controls were selected and matched for age, sex and body-mass index with the depressives. Serum lipid estimations were done in each subject after 12 hours overnight fasting. The main finding of the study is that total serum cholesterol, serum triglycerides and serum LDL cholesterol are decreased while serum HDL cholesterol is increased in depression and these changes were more marked in depressed subjects with definite suicidal intent. On regression analysis, total serum cholesterol was the most important predictive variable of the severity of depression.

Khalid, Abdul; Lal, Narottam; Trivedi, J.K.; Dalal, P.K.; Asthana, O.P.; Srivastava, J.S.; Akhtar, Asif

1998-01-01

414

Lipid metabolism and hyperlipidemia in dogs.  

PubMed

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

Xenoulis, Panagiotis G; Steiner, Jörg M

2010-01-01

415

Genomewide association studies and lipid risk factors  

Microsoft Academic Search

Plasma concentrations of lipids and lipoproteins are well-established risk factors for atherosclerotic coronary heart disease\\u000a and show substantial heritability. Identification of the genetic factors underlying such complex genetic traits, in which\\u000a multiple genes and significant gene-environment interactions contribute to the variation, has been challenging. This article\\u000a reviews recent findings from the first wave of genomewide association studies conducted to identify

Ralph Burkhardt; Eimear E. Kenny; Jan L. Breslow

2009-01-01

416

Plasma lipid profile in sarcoma patients.  

PubMed

Objective of the present study was to observe plasma lipid profile (triglycerides, cholesterol, LDL-cholesterol and HDL-cholesterol) in sarcoma patients. 120 subjects were included in the project. The subjects comprised of two groups ; first as Controls (60 in number) and the second as Patients of Sarcoma (also 60 in number). Fasting blood samples were collected for estimation. Sarcoma patients showed highly significant (P<0.01) decrease, when compared with the normal control subjects. PMID:16751129

Qadir, M Imran; Malik, Salman Akbar; Naveed, Abdul Khaliq; Ahmad, Ijaz

2006-04-01

417

Method of producing bilayer lipid membranes  

US Patent & Trademark Office Database

Methods are disclosed for producing a substrate surface supporting a continuous planar bilayer lipid membrane by covalently binding a plurality of micellar of vesicle liposomes, optionally comprising a membrane protein or other biologically active membrane-bound component, to a substrate surface supporting a self-assembled monolayer (SAM) of essentially straight long chain molecules. In one embodiment, the micellar or vesicle liposomes covantly bind to hydrophilic spacer molecules attached to the functional groups of the self-assembled monolayer.

1999-07-13

418

Effective use of combination lipid therapy  

Microsoft Academic Search

Despite the benefits of statin therapy, low-density lipoprotein (LDL) cholesterol management remains suboptimal and many patients\\u000a do not achieve their recommended target goals. The aim of combination lipid drug therapy in high-risk patients is to achieve\\u000a LDL cholesterol and non-high-density lipoprotein (HDL) cholesterol goals with a minimum of serious adverse effects. Although\\u000a statins are the drug of first choice, statin

Abu R. Vasudevan; Peter H. Jones

2006-01-01

419

Oxidation of lipids in fish meal  

Microsoft Academic Search

Oxidation of lipids in fish meal has been studied. The course of the reaction has been followed by means of oxygen absorption,\\u000a peroxide values and chromatographic analyses. The latter has been used quantitatively, because the method of methylation of\\u000a the unreacted fatty acids obtained by hydrolysis of the glyceryl esters has proved to the quantitative. The results indicate:\\u000a (a) there

Mario D. Waissbluth; Lucy Guzman; Florencio P. Plachco

1971-01-01

420

Medium chain triglycerides and structured lipids  

Microsoft Academic Search

Lipids are an essential component of our body composition and necessary in our daily food intake. Conventional fats and oils\\u000a are composed of glycerides of long chain fatty acids and are designated as long chain triglycerides (LCT). Body fat as well\\u000a as the fats and oils in our daily intake fall into this category. In enteral and parenteral hyperalimentation, we

Vigen K. Babayan

1987-01-01

421

Lipids of Human and Equine Smegma  

Microsoft Academic Search

The lipids of human and equine smegma pools were saponified and the total fatty acids submitted to temperature-programmed gas chromatography (GC) analysis. In contrast to the human products, the horse smegma fatty acids contained very low odd saturated as well as olefinic branched chain acid contents. The cyclopropane fatty acid, 9,10-methyleneoctadecanoic acid, occurred in smegma sampled from men over 35

H. J. O’Neill; L. L. Gershbein

1976-01-01

422

Anomalously fast kinetics of lipid monolayer buckling  

NASA Astrophysics Data System (ADS)

We re-examine previous observations of folding kinetics of compressed lipid monolayers. We set conservative limits on a) the energy released in the mechanical buckling process and b) the kinetic energy entailed by the observed folding motion. These limits imply a kinetic energy at least thirty times greater than the energy supplied by the buckling instability. The most likely source for the needed kinetic energy is self adhesion of the hydrophobic faces of the fold, not previously thought to be essential.

Oppenheimer, Naomi; Diamant, Haim; Witten, Thomas

2013-03-01

423

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

424

Pore formation in lipid membranes by alamethicin.  

PubMed Central

The conformation of the linear peptide antibiotic alamethicin in dipalmitoyl phosphatidylcholine multilayers was investigated in the absence of an electric field by means of infrared attenuated total reflection spectroscopy. Alamethicin was found to be incorporated into the lipid membrane not only in the dry state but also in an aqueous environment. Its molecular conformation, however, changed from a helix when dry to an extended chain when aqueous. The extended chain aggregated to di- and multimers spanning the lipid bilayer. The equilibrium concentration of alamethicin in the surrounding water was 90 nM, which is in the range of concentrations used in black film experiments. The corresponding molar ratio of lipid to peptide was 80:1. Concerning the molecular mechanism of electric field-induced pore formation, one has to conclude that the dipole model proposed by several authors is very unlikely because it is based on the assumption that the major part of alamethicin is adsorbed on the membrane surface, from which small amounts flip into the membrane under the influence of an electric field. An alternative mechanism is proposed, based on a field-induced conformational change of the peptide from the extended state to a helix. This transition is favored by the resulting dipole moment of the alamethicin helix.

Fringeli, U P; Fringeli, M

1979-01-01

425

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.

2005-04-01

426

Phytic Acid Inhibits Lipid Peroxidation In Vitro  

PubMed Central

Phytic acid (PA) has been recognized as a potent antioxidant and inhibitor of iron-catalyzed hydroxyl radical formation under in vitro and in vivo conditions. Therefore, the aim of the present study was to investigate, with the use of HPLC/MS/MS, whether PA is capable of inhibiting linoleic acid autoxidation and Fe(II)/ascorbate-induced peroxidation, as well as Fe(II)/ascorbate-induced lipid peroxidation in human colonic epithelial cells. PA at 100??M and 500??M effectively inhibited the decay of linoleic acid, both in the absence and presence of Fe(II)/ascorbate. The observed inhibitory effect of PA on Fe(II)/ascorbate-induced lipid peroxidation was lower (10–20%) compared to that of autoxidation. PA did not change linoleic acid hydroperoxides concentration levels after 24 hours of Fe(II)/ascorbate-induced peroxidation. In the absence of Fe(II)/ascorbate, PA at 100??M and 500??M significantly suppressed decomposition of linoleic acid hydroperoxides. Moreover, PA at the tested nontoxic concentrations (100??M and 500??M) significantly decreased 4-hydroxyalkenal levels in Caco-2 cells which structurally and functionally resemble the small intestinal epithelium. It is concluded that PA inhibits linoleic acid oxidation and reduces the formation of 4-hydroxyalkenals. Acting as an antioxidant it may help to prevent intestinal diseases induced by oxygen radicals and lipid peroxidation products.

Weglarz, Ludmila; Dzierzewicz, Zofia

2013-01-01

427

Plasma flux-dependent lipid A deactivation  

NASA Astrophysics Data System (ADS)

This paper reports the influence of gas plasma flux on endotoxin lipid A film deactivation. To study the effect of the flux magnitude of reactive species, a modified low-pressure inductively coupled plasma (ICP) with O radical flux ?1016 cm?2 s?1 was used. After ICP exposures, it was observed that while the Fourier transform infrared absorbance of fatty chains responsible for the toxicity drops by 80% through the film, no obvious film endotoxin deactivation is seen. This is in contrast to that previously observed under low flux exposure conducted in a vacuum beam system: near-surface only loss of fatty chains led to significant film deactivation. Secondary ion mass spectrometry characterization of changes at the film surface did not appear to correlate with the degree of deactivation. Lipid A films need to be nearly completely removed in order to detect significant deactivation under high flux conditions. Additional high reactive species flux experiments were conducted using an atmospheric pressure helium plasma jet and a UV/ozone device. Exposure of lipid A films to reactive species with these devices showed similar deactivation behaviour. The causes for the difference between low and high flux exposures may be due to the nature of near-surface structural modifications as a function of the rate of film removal.

Chang, Hung-Wen; Hsu, Cheng-Che; Ahmed, Musahid; Liu, Suet Yi; Fang, Yigang; Seog, Joonil; Oehrlein, Gottlieb S.; Graves, David B.

2014-06-01

428

Impaired plasma lipid profiles in acute hepatitis  

PubMed Central

The present study examined plasma lipid profiles in thirty patients suffered from acute viral hepatitis. Patients' blood samples were collected at both the debut and recovery of diseases. Thirty sex and age matched normal subjects were included as controls. Plasma total triglycerides (TG), total cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apolipoprotein AI (ApoAI), apolipoprotein B (ApoB), lipoprotein (a) (Lp(a)), blood coagulation status including prothrombin complex activity and activated partial tromboplastin time (APTT), and hepatic functions were determined by the automatic biochemical analytical instrument. It demonstrated that plasma levels of total cholesterol, HDL-C and apoAI were significantly lower in the patients at the acute phase of hepatitis than those in normal subjects, whereas plasma levels of TG and LDL-C were obviously higher in the patients than in normal subjects (P < 0.05). Moreover, we demonstrated that patients' plasma levels of total cholesterol, LDL-C, HDL-C and apoAI were lower at the active phase of the diseases than at the recovering phase, which indicating that acute liver damage could significant influence lipid metabolism in vivo. No pathological changes of blood coagulation status occurred in these patients during the study as all selected patients had moderate hepatitis. It may conclude that examinations of plasma lipid profile could be considered as a clinical index to reflect liver damage in the active phase of hepatitis.

2010-01-01

429

Stiffened lipid platforms at molecular force foci  

PubMed Central

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

Anishkin, Andriy; Kung, Ching

2013-01-01

430

Nonlinear vibrational microscopy applied to lipid biology.  

PubMed

Optical microscopy is an indispensable tool that is driving progress in cell biology. It still is the only practical means of obtaining spatial and temporal resolution within living cells and tissues. Most prominently, fluorescence microscopy based on dye-labeling or protein fusions with fluorescent tags is a highly sensitive and specific method of visualizing biomolecules within sub-cellular structures. It is however severely limited by labeling artifacts, photo-bleaching and cytotoxicity of the labels. Coherent Raman Scattering (CRS) has emerged in the last decade as a new multiphoton microscopy technique suited for imaging unlabeled living cells in real time with high three-dimensional spatial resolution and chemical specificity. This technique has proven to be particularly successful in imaging unstained lipids from artificial membrane model systems, to living cells and tissues to whole organisms. In this article, we will review the experimental implementations of CRS microscopy and their application to imaging lipids. We will cover the theoretical background of linear and non-linear vibrational micro-spectroscopy necessary for the understanding of CRS microscopy. The different experimental implementations of CRS will be compared in terms of sensitivity limits and excitation and detection methods. Finally, we will provide an overview of the applications of CRS microscopy to lipid biology. PMID:24051337

Zumbusch, Andreas; Langbein, Wolfgang; Borri, Paola

2013-10-01

431

Extolling the benefits of molecular therapeutic lipidation.  

PubMed

The conjugation of drug or molecular recognition motif to a hydrophobic fatty entity, for purpose of drug-membrane localization, has been a molecular strategy utilized for targeted inhibition of pathways involved in diseased cells. In general, membrane-anchored inhibitor structures have been composed of either a lipid or sterol group coupled via a broad range of inert linkers to either a peptide or small molecule protein recognition agent. Whilst not adhering to the molecular paradigms of modern medicinal chemistry, this approach has afforded peptidic-based therapeutics with improved cellular and in vivo efficacy, leading to more selective targeting of membrane associated protein targets and the effective immobilization of cytosolic signaling proteins through membrane anchorage. The evidence suggests that membrane-anchored peptidic inhibitors are more selective, potent, structurally rigid, and possess enhanced cell permeability profiles as compared to their non-lipidated precursors. This perspectives article will review the application of lipid or sterol conjugation to peptide inhibitors (lipo-molecules) to circumvent the poor cell permeability and metabolic labilities associated with peptidic therapeutics. In addition, the concept of protein-membrane anchorage as a novel drug modality for inhibiting cytosolic signaling protein motility in cells will be reviewed and its merits as an approach to inhibiting protein complexation, protein nuclear translocation and their potential for more effective targeting of membrane associated targets. PMID:23771042

Avadisian, Miriam; Gunning, Patrick T

2013-09-01

432

Ether lipid generating enzyme AGPS alters the balance of structural and signaling lipids to fuel cancer pathogenicity  

PubMed Central

Aberrant lipid metabolism is an established hallmark of cancer cells. In particular, ether lipid levels have been shown to be elevated in tumors, but their specific function in cancer remains elusive. We show here that the metabolic enzyme alkylglyceronephosphate synthase (AGPS), a critical step in the synthesis of ether lipids, is up-regulated across multiple types of aggressive human cancer cells and primary tumors. We demonstrate that ablation of AGPS in cancer cells results in reduced cell survival, cancer aggressiveness, and tumor growth through altering the balance of ether lipid, fatty acid, eicosanoid, and fatty acid–derived glycerophospholipid metabolism, resulting in an overall reduction in the levels of several oncogenic signaling lipids. Taken together, our results reveal that AGPS, in addition to maintaining ether lipids, also controls cellular utilization of fatty acids, favoring the generation of signaling lipids necessary for promoting the aggressive features of cancer.

Benjamin, Daniel I.; Cozzo, Alyssa; Ji, Xiaodan; Roberts, Lindsay S.; Louie, Sharon M.; Mulvihill, Melinda M.; Luo, Kunxin; Nomura, Daniel K.

2013-01-01

433

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

PubMed

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

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

2014-06-01

434

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

PubMed Central

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

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

2014-01-01

435

Effects of porcine hemoglobin on serum lipid content and fecal lipid excretion in rats.  

PubMed

The purpose of this study was to elucidate the effects of dietary hemoglobin on serum and liver lipid contents in rats, and the ability of hemoglobin hydrolysates to disrupt lipid absorption. After rats had been fed on casein- or porcine hemoglobin-containing diets for 4 weeks, their serum and liver lipid contents and fecal cholesterol, bile acid, and nitrogen excretion were measured. To elucidate the mechanism of lipid absorption by dietary hemoglobin, we also examined lipase activity, micellar solubility of cholesterol, and bile acid binding activity in the presence of hemoglobin hydrolysates. Dietary hemoglobin decreased serum and liver triglyceride and cholesterol contents and increased fecal fatty acid, cholesterol, and bile acid excretion. In addition, hemoglobin hydrolysates inhibited lipase activity compared with casein hydrolysates in an in vitro study. These results suggested that the hypolipidemic effect of hemoglobin is mediated by increased fecal lipid excretion, and that decreased lipase activity by hemoglobin is at least partially responsible for this result. The observed effects were documented with an 8?g/kg hemoglobin diet, which is lower than in other studies; therefore. hemoglobin may be useful in the prevention of lifestyle-related diseases. PMID:24320987

Hosomi, Ryota; Fukunaga, Kenji; Nishiyama, Toshimasa; Yoshida, Munehiro

2014-03-01

436

Effect of tamoxifen on lipids and lipid metabolising marker enzymes in experimental atherosclerosis in Wistar rats.  

PubMed

Tamoxifen, a non-steroidal anti-oestrogen, is used in the treatment of breast cancer, both receptor positive and negative tumours. It also possesses weak oestrogenic activity which forms the basis of this study. Tamoxifen (2 different dosages) was administered through diet (10 mg/kg diet and 20 mg/kg diet) to experimental atherosclerosis induced female rats to assess the effect of tamoxifen on plasma lipid levels, lipoprotein cholesterol level and on the activity of lipid metabolising enzymes. The plasma total lipid level was increased in atherosclerosis suffering animals compared to control animals with concomitant changes in the activity of lipid metabolising enzymes. HDL-cholesterol was decreased while LDL-cholesterol and VLDL-cholesterol were increased in the atherosclerosis induced group. Cholesterol and free cholesterol were decreased in tamoxifen treated groups while the other lipids show a moderate increase. HDL-cholesterol was increased but LDL-cholesterol was decreased in the tamoxifen treated groups. The higher dosage tamoxifen given group animals show significantly favourable results from therapy stand point when compared to diseased group. PMID:9062889

Vinitha, R; Thangaraju, M; Sachdanandam, P

1997-03-01

437