Chemistry and Physics of LipidsThis is an RSS file. You can use it to subscribe to this data in your favourite RSS reader, such as GoogleReader, or to display this data on your own website or blog. Subscribe to this data using MyMedWorm.Subscribe to this data using GoogleReader.Subscribe to this data using Bloglines.Subscribe to this data using MyYahoo.

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Determination of enthalpy of formation of methyl and ethyl esters of fatty acids.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Biofuels composed by fatty acid methyl esters are widely used as partly substituting fuels for diesel fossil fuels. Additionally, it is expected that the diesel biofuel norms will be extended to ethyl esters produced from bioethanol in the upcoming years. A precise knowledge of the standard enthalpy of formation is necessary for the calculation of some parameters useful for the analysis of the combustion process and emissions of a diesel engine operating with different fuels, such as the heating value, the adiabatic flame temperature or the kinetic mechanisms. However, experimental data for this property are scarce, an...
Source: Chemistry and Physics of Lipids - November 13, 2009 Category: Lipidology Authors: Lapuerta M, Rodríguez-Fernández J, Oliva F Tags: Chem Phys Lipids Source Type: journals

Effect of tocopherol on surface properties of plastid lipids originating from wheat calli cultivated in cadmium presence.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The behaviour of equimolar mixtures of alpha-tocopherol with monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) and phospholipids (PL) isolated from wheat calli cultured on media with and without cadmium was investigated at the air-water interface by surface pressure-area (pi-A) measurements established using an automated Langmuir-type film balance. It was found that monolayers of all studied compounds were expanded. The additivity rule was not fulfilled and the collapse pressure of mixtures was different from these recorded for pure components. This can be related with the existence of interacti...
Source: Chemistry and Physics of Lipids - November 9, 2009 Category: Lipidology Authors: Gzyl-Malcher B, Zembala M, Filek M Tags: Chem Phys Lipids Source Type: journals

Oxyfunctionalization of Unactivated C-H Bonds in Triterpenoids with tert-Butylhydroperoxide Catalyzed by meso-5,10,15,20-Tetramesitylporphyrinate Osmium(II) Carbonyl Complex.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A system consisting of meso-5,10,15,20-tetramesitylporphyrinate osmium(II) carbonyl complex [Os(TMP)CO] as a precatalyst and tert-butylhydroperoxide (TBHP) as an oxygen donor is shown to be an efficient, regioselective oxidant system for the allylic oxidation, ketonization and hydroxylation of unactivated C-H bonds in a series of the peracetate derivatives of penta- and tetracyclic triterpenoids. Treatment of the substrates with this oxidant system afforded a variety of novel or scarce oxygenated derivatives in one-step. Structures of the isolated components, after chromatographic separation, were determined by spectro...
Source: Chemistry and Physics of Lipids - November 6, 2009 Category: Lipidology Authors: Ogawa S, Wakatsuki Y, Makino M, Fujimoto Y, Yasukawa K, Kikuchi T, Ukiya M, Akihisa T, Iida T Tags: Chem Phys Lipids Source Type: journals

Properties of sesame oil by detailed (1)H and (13)C-NMR assignments before and after ozonation and their correlation with iodine value, peroxide value, and viscosity measurements.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Gaseous ozone chemically reacts with unsaturated triglyceride substrates leading to ozonated derivatives with a wide potential applications, ranging from the petrochemical to the pharmaceutical industry. To date, an ultimate understanding of the ozone reactivity during sesame oil ozonation process as well as detailed (1)H and (13)C-NMR assignments are lacking. A practical advantage of NMR is that a single NMR sample measurement can explain many issues, while similar analysis by traditional methods may require several independent and time-consuming measurements. Moreover, significant relationships among NMR spectra and ...
Source: Chemistry and Physics of Lipids - November 6, 2009 Category: Lipidology Authors: Sega A, Zanardi I, Chiasserini L, Gabbrielli A, Bocci V, Travagli V Tags: Chem Phys Lipids Source Type: journals

A high yield procedure for the preparation of arsonolipids (2,3-diacyloxypropylarsonic acids).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The crucial step in the preparation of the title arsonolipids starting from the dichloromethane-soluble dithioarsonite CH(2)(OH)CH(OH)CH(2)-As(SPh)(2) is to avoid an internal cyclization during the acylation which protects the primary -OH group from being acylated. This was to a large extent accomplished by using fatty acyl chloride in the presence of the weak base pyridine and controlling the temperature and rate of the acyl chloride addition, giving approximately 70% yields of arsonolipids. The presence of catalytic amounts of 4-dimethylaminopyridine boosted the yields to 82-85%. This yield is a great improvement ove...
Source: Chemistry and Physics of Lipids - November 6, 2009 Category: Lipidology Authors: Ioannou PV, Tsivgoulis GM Tags: Chem Phys Lipids Source Type: journals

Liposome fractionation and size analysis by asymmetrical flow field-flow fractionation/multi-angle light scattering: influence of ionic strength and osmotic pressure of the carrier liquid.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Asymmetrical flow field-flow fractionation (AsFlFFF) / multi-angle light scattering (MALS) was employed for studying filter-extruded liposomes in carrier solutions with different ionic strength and osmolarity. By dilution of preformed liposome suspensions with different media, only the ionic strength in the external free aqueous phase was changed. Under such conditions the liposomes were found to elute at almost identical elution times, which is in contrast to earlier studies. This may be explained by two opposing effects: a) modulation of interparticulate and particle-wall-repulsion effects and b) osmotic stress-induc...
Source: Chemistry and Physics of Lipids - November 6, 2009 Category: Lipidology Authors: Hupfeld S, Moen HH, Ausbacher D, Haas H, Brandl M Tags: Chem Phys Lipids Source Type: journals

The intact muscle lipid composition of bulls:Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The objective of the study was to investigate whether matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry and (31)P nuclear magnetic resonance (NMR) spectroscopy are useful tools to study the intact lipid composition of beef. For the MALDI-TOF MS and (31)P NMR investigations muscle samples were selected from a feeding experiment with German Simmental bulls fed different diets. Beside the triacylglycrol (TAGs), phosphatidylethanolamine (PE), phosphatidylcholine (PC) and phosphatidylinositol (PI) species the MALDI-TOF mass spectra of total muscle lipids gave also intense signals of ca...
Source: Chemistry and Physics of Lipids - November 6, 2009 Category: Lipidology Authors: Dannenberger D, Süß R, Teuber K, Fuchs B, Nuernberg K, Schiller J Tags: Chem Phys Lipids Source Type: journals

Impact of the long chain omega-acyl ceramides on the Stratum corneum lipid nanostructure. Part 1: Thermotropic phase behaviour of CER[EOS] and CER[EOP] studied using X-ray powder diffraction and FT-Raman spectroscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The stratum corneum (SC), the outermost layer of the mammalian skin, is the main skin barrier. Ceramides (CERs) as the major constituent of the SC lipid matrix are of particular interest. At the moment, eleven classes of CERs are identified, but the effect of each single ceramide species is still not known. Therefore in this article, the thermotropic behaviour of the long chain omega-acylceramides CER[EOS] and CER[EOP] was studied using X-ray powder diffraction and FT-Raman spectroscopy. It was found that the omega-acylceramides CER[EOS] and CER[EOP] do not show a pronounced polymorphism which is observed for shorter c...
Source: Chemistry and Physics of Lipids - November 6, 2009 Category: Lipidology Authors: Kessner D, Brezesinski G, Funari SS, Dobner B, Nëubert RH Tags: Chem Phys Lipids Source Type: journals

Simultaneous Monitoring of Electroformation of Phospholipid Vesicles by Quartz Crystal Microbalance and Optical Microscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The electroformation of giant vesicles from 1, 2-Dimyristoyl-sn-Glycero-3-Phosphocholine (DMPC) was monitored using Quartz crystal microbalance with dissipation monitoring (QCM-D) and optical microscopy, simultaneously using a novel sample cell design. A gold-coated QCM crystal was used as one of the electrodes and an Indium tin oxide (ITO)-coated glass slide was used as the second electrode for electroformation. Increases in the frequency and decreases in the dissipation were observed immediately upon voltage application between the two electrodes, indicating the loss of lipid from the QCM surface. Concurrently, we ob...
Source: Chemistry and Physics of Lipids - October 30, 2009 Category: Lipidology Authors: Niri VH, Flatt BK, Fakhraai Z, Forrest JA Tags: Chem Phys Lipids Source Type: journals

Biophysical studies of the interaction of squalamine and other cationic amphiphilic molecules with bacterial and eukaryotic membranes. Importance of the distribution coefficient in membrane selectivity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The interaction of squalamine (SQ) with eukaryotic and prokaryotic membranes was studied and compared with the interaction of two other cationic amphipathic antimicrobials (CAA), i.e. the antibiotic polymyxin B (PMB) and the detergent hexadecyltrimethylammonium bromide (CTAB). Whole cell experiments showed that the three CAA have in common the ability to interact with lipopolysaccharide-containing membranes through a divalent cation sensitive process. Differences were found regarding their kinetics of membrane permeabilisation and their selectivity for bacteria, with a preferential permeabilisation of bacteria by PMB &...
Source: Chemistry and Physics of Lipids - October 30, 2009 Category: Lipidology Authors: Di Pasquale E, Salmi-Smail C, Brunel JM, Sanchez P, Fantini J, Maresca M Tags: Chem Phys Lipids Source Type: journals

Oxidizability of cardiac cardiolipin in Triton X-100 micelles as determined by using a Clark electrode.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The kinetics of the chain free-radical oxidation of cardiolipin (CL), a unique phospholipid containing four linoleate moieties, have been studied for the first time. The technique based on monitoring oxygen consumption by using a Clark electrode was applied to determine the oxidizability of CL during its initiated oxidation in aqueous Triton X-100 micelles in 50mM phosphate buffer, pH 7.40, at 37 degrees C. The oxidizability was characterized by the k(2)/2k(3) ratio, where k(2) and k(3) are the rate constants for the reaction of chain propagation (LO(2)+LH-->LOOH+L) and chain termination (2LO(2)-->products), corr...
Source: Chemistry and Physics of Lipids - October 29, 2009 Category: Lipidology Authors: Roginsky V Tags: Chem Phys Lipids Source Type: journals

Binding of a cationic phenazinium dye in anionic liposomal membrane: A spectacular modification in the photophysics.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Interaction of a cationic phenazinium dye, phenosafranin (PSF), with the anionic liposomal vesicle/bilayer of dimyristoyl-L-alpha-phosphatidylglycerol (DMPG) has been demonstrated using steady-state and time resolved fluorescence and fluorescence anisotropy techniques. The charge transfer emission spectrum of PSF shows a dramatic modification in terms of fluorescence yield together with an appreciable hypsochromic shift in the lipid environment. The blue shift indicates a lowering in polarity inside the vesicle as compared to that in bulk water. The fluorescence and fluorescence quenching studies and micropolarity dete...
Source: Chemistry and Physics of Lipids - October 26, 2009 Category: Lipidology Authors: Bose D, Ghosh D, Das P, Girigoswami A, Sarkar D, Chattopadhyay N Tags: Chem Phys Lipids Source Type: journals

Lipid Domains and Mechanical Plasticity of Escherichia coli Lipid Monolayers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lipid monolayers can be laterally dilated under the action of the barriers in a Langmuir trough thus allowing for measurements of their mechanical response. We study the stress response of E. coli polar lipid extract and POPC against oscillatory deformations stressed up to a 20 % of the initial area. For E. coli monolayers a nonlinear regime described by a series of Fourier harmonics of the excitation mode is found beyond a critical strain (u(C) approximately 1%). In contrast, the mechanical response of POPC monolayers is found linear upon much larger deformations. For E. coli monolayers the stress-strain plot reflects...
Source: Chemistry and Physics of Lipids - October 23, 2009 Category: Lipidology Authors: López-Montero I, Arriaga LR, Rivas G, Vélez M, Monroy F Tags: Chem Phys Lipids Source Type: journals

Synthesis of oligo(ethylene glycol) substituted phosphatidylcholines: secretory PLA2-targeted precursors of NSAID prodrugs.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A series of new phosphatidylcholine analogues with structurally modified sn-2-substituents have been prepared. The synthetic compounds include oligo(ethylene glycol) derivatives with chainterminal pharmacophores that upon catalytic hydrolysis by phospholipase A2 yielded a series of oligo(ethylene glycol)-conjugates of the respective drugs. The approach here outlined may open a new way to employ OEG derivatives of phospholipids for therapeutic applications as secretory PLA2- targeted precursors of prodrugs. PMID: 19837049 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids)
Source: Chemistry and Physics of Lipids - October 14, 2009 Category: Lipidology Authors: Rosseto R, Hajdu J Tags: Chem Phys Lipids Source Type: journals

Interaction of N,N,N-trialkylammonioundecahydro-closo-dodecaborates with dipalmitoyl phosphatidylcholine liposomes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
N,N,N-trialkylammonioundecahydrododecaborates (1-), a novel class of compounds of interest for use as anions in ionic liquids, interact with DPPC liposomes. Increasing compound concentration cause an increasing negative zeta potential. Dissociation constants demonstrate that the binding capacity increases strongly with longer chain length. N,N,N-trialkylammonioundecahydrododecaborates with longer alkyl chains show a detergent like behavior: the compounds incorporate into the liposome membrane and differential scanning calorimetric experiment show already low concentrations cause a complete disappearance of the peak rep...
Source: Chemistry and Physics of Lipids - September 30, 2009 Category: Lipidology Authors: Schaffran T, Li J, Karlsson G, Edwards K, Winterhalter M, Gabel D Tags: Chem Phys Lipids Source Type: journals

Preparation of reconstituted acetylcholine receptor membranes suitable for AFM imaging of lipid-protein interactions.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The nicotinic acetylcholine receptor (nAChR) has been reconstituted in POPC vesicles at high lipid-protein (L/P) ratios for preparation of supported lipid bilayers with a low protein density for studies of protein-lipid interactions using atomic force microscopy (AFM). Initial reconstitutions using a standard dialysis method with bulk L/P ratios ranging from 20:1 to 100:1 (w/w) gave heterogeneous samples that contained both empty vesicles and proteoliposomes with a range of L/P ratios. This is problematic because empty vesicles adsorb and rupture to form bilayer patches more rapidly than do protein-rich vesicles, resul...
Source: Chemistry and Physics of Lipids - September 30, 2009 Category: Lipidology Authors: Vuong N, Baenziger JE, Johnston LJ Tags: Chem Phys Lipids Source Type: journals

Induction of non-lamellar lipid phases by antimicrobial peptides: A potential link to mode of action.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Antimicrobial peptides are naturally produced by numerous organisms including insects, plants and mammals. Their non-specific mode of action is thought to involve the transient perturbation of bacterial membranes but the molecular mechanism underlying the rearrangement of the lipid molecules to explain the formation of pores and micelles is still poorly understood. Biological membranes mostly adopt planar lipid bilayers; however, antimicrobial peptides have been shown to induce non-lamellar lipid phases which may be intimately linked to their proposed mechanisms of action. This paper reviews antimicrobial peptides that...
Source: Chemistry and Physics of Lipids - September 28, 2009 Category: Lipidology Authors: Haney EF, Nathoo S, Vogel HJ, Prenner EJ Tags: Chem Phys Lipids Source Type: journals

New aspects of the regulation of glycosphingolipid receptor function.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We propose that the fatty acid heterogeneity of glycosphingolipids may compensate for the relative few and simple glycosphingolipid structures found in mammalian cells. Variation in GSL fatty acid composition may mediate aglycone regulation of GSL membrane receptor function by a differential interaction with cholesterol and other membrane components which may be differentially organized within plasma membrane lipid domains. These concepts are specifically illustrated in model membrane studies and in relation to the role of the glycolipid, globotriaosyl ceramide(Gb(3)) in verotoxin-induced renal pathology and gp120 bind...
Source: Chemistry and Physics of Lipids - September 21, 2009 Category: Lipidology Authors: Lingwood CA, Manis A, Mahfoud R, Khan F, Binnington B, Mylvaganam M Tags: Chem Phys Lipids Source Type: journals

Effect of synthetic and natural phospholipids on N-acylphosphatidylethanolamine-hydrolyzing phospholipase D activity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
N-acylethanolamines (NAEs) constitute a family of endogenous bioactive lipids that includes arachidonoylethanolamide (anandamide), palmitoylethanolamide (PEA) and oleoylethanolamide (OEA). These lipids are formed from their respective N-acylated ethanolamine phospholipid (NAPE) precursor by the action of a phospholipase D enzyme (NAPE-PLD). Anandamide, OEA, and PEA are all bioactive lipids that may influence, amongst others: neuroinflammation, food intake, and oocyte implantation. Here we have synthesized a number of NAPE analogues with variation in the phosphoester structure. The NAPE analogues as well as selected pho...
Source: Chemistry and Physics of Lipids - August 24, 2009 Category: Lipidology Authors: Petersen G, Pedersen AH, Pickering DS, Begtrup M, Hansen HS Tags: Chem Phys Lipids Source Type: journals

Polymorphism in 'L' shaped lipids: Structure of N-, O-diacylethanolamines with mixed acyl chains.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, two DAEs with mixed acyl chains, namely N-palmitoyl, O-octanoylethanolamine and N-palmitoyl, O-decanoylethanolamine have been synthesized and their 3-dimensional structures were determined. Both the compounds were found to adopt 'L' shaped structures and exist in two polymorphic forms, alpha and beta. In the alpha form a mixed-type chain packing has been observed whereas in the beta form the chain packing is symmetric. Similar polymorphic forms are likely to exist in other 'L' shaped lipids such as 1,3-diacylglycerols and ceramides, where polymorphism has been detected earlier, but 3-dimentioanal structures ...
Source: Chemistry and Physics of Lipids - August 23, 2009 Category: Lipidology Authors: Tarafdar PK, Swamy MJ Tags: Chem Phys Lipids Source Type: journals

Ultrasound, Liposomes, and Drug Delivery: Principles for Using Ultrasound to Control the Release of Drugs from Liposomes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ultrasound is used in many medical applications, such as imaging, blood flow analysis, dentistry, liposuction, kidney stone disruption, and tumor and fibroid ablation. In the past, low frequency ultrasound (LFUS) was the main method to downsize multilamellar (micron range) vesicles into small (nano scale) unilamellar vesicles. Recently, the ability of ultrasound to induce localized and controlled drug release from liposomes, utilizing thermal and/or mechanical effects, has been shown. This review, deals with the interaction of ultrasound with liposomes, focusing mainly on the mechanical mechanism of drug release from l...
Source: Chemistry and Physics of Lipids - August 20, 2009 Category: Lipidology Authors: Schroeder A, Kost J, Barenholz Y Tags: Chem Phys Lipids Source Type: journals

Cytochrome c Interaction with Neutral Lipid Membranes: Influence of Lipid Packing and Protein Charges.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The interaction of cytochrome c (cyt c) with fluid/gel neutral supported lipid membranes was investigated by time-lapse atomic force microscopy (AFM). AFM revealed the random formation of depressed areas in fluid membranes promoted by cyt c. These depressions corresponded to the desorption of fluid bilayer patches induced by cyt c. By contrast, the gel domains were never desorbed but they were progressively thickened in the presence of the protein. These results suggest that cyt c molecules might intercalate between the mica and the lipid bilayer. Although the interaction of cyt c with the mica surface is likely to be ...
Source: Chemistry and Physics of Lipids - August 19, 2009 Category: Lipidology Authors: Kirat KE, Morandat S Tags: Chem Phys Lipids Source Type: journals

alpha-Helical Transmembrane Peptides: A "Divide and Conquer" Approach to Membrane Proteins (Invited Review).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
alpha-helical membrane proteins fulfill many vital roles in all living cells and constitute the majority of drug targets. However, their relevance is in no way paralleled by our current understanding of their structures and functions. This is because membrane proteins present a number of experimental obstacles that are difficult to surmount by classical methods developed for water-soluble proteins. Moreover, membrane proteins are not only challenging on their very own but, when embedded in a biological membrane, also reside in an outstandingly complex milieu. These difficulties have fostered a "divide and conquer" appr...
Source: Chemistry and Physics of Lipids - August 11, 2009 Category: Lipidology Authors: Bordag N, Keller S Tags: Chem Phys Lipids Source Type: journals

The total synthesis of 2-O-arachidonoyl-1-O-stearoyl-sn-glycero-3-phosphocholine-1,3,1'-(13)C(3) and -2,1'-(13)C(2) by a novel chemoenzymatic method.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
2-O-Arachidonoyl-1-O-stearoyl-sn-glycero-3-phosphocholine was synthesized with carbon-13 enrichment of the three glycerol carbons and the carbonyl of the stearoyl group. Phospholipase A(2) was utilized to give optically pure lyso-PC, and only 3% acyl migration occurred during reacylation with arachidonic acid anhydride. This phospholipid is an important biosynthetic precursor of arachidonic acid metabolites as well as the endocannabinoid 2-arachidonoylglycerol (2-AG), and is now available for NMR studies. PMID: 19682980 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids)
Source: Chemistry and Physics of Lipids - August 11, 2009 Category: Lipidology Authors: Duclos RI Tags: Chem Phys Lipids Source Type: journals

Defining Lipid-Binding Regions of Human Serum Amyloid A Using Its Fragment Peptides.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Human serum amyloid A (SAA) protein is an apolipoprotein predominantly present in the high-density lipoprotein fraction of plasma. Despite its critical roles in lipid metabolism, especially in acute phases, systematic understanding of the lipid interaction of this protein is limited. Lipid-binding properties of synthetic fragment peptides corresponding to the N-terminal (residues 1-27), central (residues 43-63), and C-terminal (residues 77-104) parts of SAA molecule were examined. SAA (1-27) peptide binds to lipid forming an alpha-helical structure, whereas SAA (43-63) and (77-104) peptides do not display binding to li...
Source: Chemistry and Physics of Lipids - August 5, 2009 Category: Lipidology Authors: Ohta S, Tanaka M, Sakakura K, Kawakami T, Aimoto S, Saito H Tags: Chem Phys Lipids Source Type: journals

Determination of the Forces Imposed by Micro and Nanopipettes during DOPC:DOPS Liposome Manipulation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Using micropipette-based probing methods and an image processing algorithm for measuring deformation, the bending energies of aspirated DOPC:DOPS liposomes were estimated both before and during manipulation with an injection pipette. We found that unlike cells, which are penetrable with pipettes as large as 2mum in diameter and at speeds as slow as 4mum/sec, liposomes, without a cytoskeleton to resist deformation, are impenetrable with pipettes as small as 25nm in diameter and at speeds as great as 4000mum/sec. Using energy calculations and the previously published mechanical properties of DOPC:DOPS liposomes, the forc...
Source: Chemistry and Physics of Lipids - August 5, 2009 Category: Lipidology Authors: Allen KB, Layton BE Tags: Chem Phys Lipids Source Type: journals

Lipid dependence of ABC transporter localization and function.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Lipid rafts have been implicated in many cellular functions, including protein and lipid transport and signal transduction. ATP-binding cassette (ABC) transporters have also been localized in these membrane domains. In this review the evidence for this specific localization will be evaluated and discussed in terms of relevance to ABC transporter function. We will focus on three ABC transporters of the A, B and C subfamily, respectively. Two of these transporters are relevant to multidrug resistance in tumor cells (Pgp/ABCB1 and MRP1/ABCC1), while the third (ABCA1) is extensively studied in relation to the reverse chole...
Source: Chemistry and Physics of Lipids - July 30, 2009 Category: Lipidology Authors: Klappe K, Hummel I, Hoekstra D, Kok JW Tags: Chem Phys Lipids Source Type: journals

The oxidized form of cholesterol 3beta-hydroxy-5-oxo-5,6-secocholestan-6-al induces structural and thermotropic changes in phospholipids membranes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The effect of an oxidized form of cholesterol, 3beta-hydroxy-5-oxo-5,6-secocholestan-6-al on the thermotropic and structural properties of phospholipid membranes was investigated by differential scanning calorimetry and X-ray diffraction and compared with that of cholesterol. The phospholipids studied included 1-palmitoyl-2-oleoylphosphatidylserine, dipalmitoleoylphosphatidylethanolamine, 1-palmitoyl-2-oleoylphosphatidylethanolamine, dipalmitoleoylphosphatidylcholine, 1-palmitoyl-2-oleoylphosphatidylcholine. Depending on the constituent phospholipids, atheronal A is observed to shift phase transitions, disrupt stacking...
Source: Chemistry and Physics of Lipids - July 30, 2009 Category: Lipidology Authors: Bach D, Epand RF, Epand RM, Miller IR, Wachtel E Tags: Chem Phys Lipids Source Type: journals

Direct ESI-MS analysis of O-acyl glycosylated cardiolipins from the thermophilic bacterium Alicyclobacillus acidoterrestris.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We used direct ESI-MS analysis to identify derivatives of cardiolipin molecular species (i.e. O-acyl glycosylated cardiolipins) from the thermophilic bacterium Alicyclobacillus acidoterrestris. We used triple-quadrupole type mass spectrometer for analysis of this complex lipid and enzymatic hydrolysis and (1)H and (13)C NMR for the identification of these cardiolipin derivatives. These techniques enabled us to identify and quantify the specific molecular species profiles of derivatives of cardiolipin directly from lipid extracts of the bacterium including the identification of the sugar moiety as alpha-D-mannose and al...
Source: Chemistry and Physics of Lipids - July 30, 2009 Category: Lipidology Authors: Rezanka T, Siristova L, Melzoch K, Sigler K Tags: Chem Phys Lipids Source Type: journals

Evidence in the formation of Conjugated Linoleic Acids from thermally induced 9t12t linoleic acid: A study by Gas Chromatography and infrared spectroscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Thermally induced isomerisation leading to the formation of Conjugated Linoleic Acids (CLA) has been observed for the first time during the thermal treatment of 9t12t fatty acid triacylglycerol, and methyl ester. Fifteen microlitre portions of the triacylglycerol sample containing 9t12t fatty acid (trilinoelaidin) were placed in micro glass ampoules and sealed under nitrogen, then subjected to thermal treatment at 250(o)C. The glass ampoules were removed at regular time intervals, cut open, and the contents were analysed by infrared spectroscopy using a single reflectance attenuated total internal reflectance crystal a...
Source: Chemistry and Physics of Lipids - July 15, 2009 Category: Lipidology Authors: Christy AA Tags: Chem Phys Lipids Source Type: journals

Chain asymmetry alters thermotropic and barotropic properties of phospholipid bilayer membranes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The alignment of the sn-1 and sn-2 acyl chains at the terminal methyl ends generally produces significant influence on the thermodynamic properties of the bilayer phase transitions. We investigated the bilayer phase behavior of asymmetric phospholipids, myristoylpalmitoylphosphatidylcholine and palmitoylmtristoylphosphatidylcholine, by high-pressure light-transmittance and Prodan-fluorescence techniques and differential scanning calorimetry. Constructed temperature-pressure phase diagrams revealed that no stable L(beta)' phase can exist in the whole pressure range because of the formation of most stable L(c) phase. Nev...
Source: Chemistry and Physics of Lipids - July 15, 2009 Category: Lipidology Authors: Goto M, Ishida S, Tamai N, Matsuki H, Kaneshina S Tags: Chem Phys Lipids Source Type: journals

High-resolution J-coupled (13)C MAS NMR spectroscopy of lipid membranes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We propose the use of Lee-Goldburg decoupling in high-resolution natural abundance (13)C CP-MAS NMR spectroscopy to obtain J-resolved multiplets from membrane lipids, and the use of these in spectral assignment and to investigate changes in molecular and segmental dynamics within chemical shift-resolved lipid groups. Spectroscopic characteristics of hydrated DPPC bilayers are reported, including J(1)(CH)-couplings from the liquid crystalline and gel phases. The observed J(1theta)(CH) values are scaled in the Lee-Goldburg experiment by a factor of approximately 3(-1/2) and corrected J(1)(CH) values on the order of 150Hz...
Source: Chemistry and Physics of Lipids - July 15, 2009 Category: Lipidology Authors: Ciesielski F, Griffin DC, Rittig M, Bonev BB Tags: Chem Phys Lipids Source Type: journals

Interaction of a bacterial dirhamnolipid with phosphatidylcholine membranes: a biophysical study.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
FTIR spectroscopy and fluorescence polarization were used to show that a bacterial dirhamnolipid interacts with phospholipid membranes composed of DPPC, altering both the acyl chain and the interfacial region of the bilayer. Incorporation of increasing amounts of dirhamnolipid into (2)H-DPPC membranes broadened the transition and shifted the transition temperature toward lower values, according to the effect on the CD(2) stretching vibration. Examination of the (13)C=O stretching band of (13)C-DPPC indicated that, both below and above the phase transition, dirhamnolipid produced a shift of the band frequency toward hig...
Source: Chemistry and Physics of Lipids - July 2, 2009 Category: Lipidology Authors: Sánchez M, Aranda FJ, Teruel JA, Ortiz A Tags: Chem Phys Lipids Source Type: journals

Hydrophilic carotenoids: Facile syntheses of carotenoid oxime hydrochlorides as long-chain, highly unsaturated cationic (bola)amphiphiles.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Stable cationic carotenoid aggregates - predominantly of the J-type - develop when the hydrochlorides of carotenoid aldoximes and ketoximes are exposed to water. The oxime hydrochlorides are obtained by simple syntheses from commercially available food color carotenoids. Bluish-purple, unstable transient compounds were observed during hydrochlorination performed at liquid nitrogen temperature. PMID: 19580794 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids)
Source: Chemistry and Physics of Lipids - July 2, 2009 Category: Lipidology Authors: Willibald J, Rennebaum S, Breukers S, Hafez SH, Patel A, Opstad CL, Schmid R, Naess SN, Sliwka HR, Partali V Tags: Chem Phys Lipids Source Type: journals

Modification Of Phosphatidylserine By Hypochlorous Acid.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The binding of the heme enzyme myeloperoxidase to phosphatidylserine epitopes on the surface of non-vital polymorphonuclear leukocytes and other cells at inflammatory sites favours modifications of this phospholipid by myeloperoxidase products. As detected by MALDI-TOF mass spectrometry hypochlorous acid and the myeloperoxidase-hydrogen peroxide-chloride system convert 1,2-dipalmitoyl-sn-glycero-3-phosphoserine into 1,2-dipalmitoyl-sn-glycero-3-phosphoacetaldehyde and 1,2-dipalmitoyl-sn-glycero-3-phosphonitrile. A transient chlorimine derivative was detected using 4-chloro-alpha-cyanocinnamic acid as matrix in mass spe...
Source: Chemistry and Physics of Lipids - July 1, 2009 Category: Lipidology Authors: Flemmig J, Spalteholz H, Schubert K, Meier S, Arnhold J Tags: Chem Phys Lipids Source Type: journals

Phase behaviour of oleanolic acid/stearyl stearate binary mixtures in bulk and at the air-water interface.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The solid-liquid phase behaviour of oleanolic acid (OLA)/stearyl stearate (SS) was investigated by differential scanning calorimetry and polarizing optical microscopy. A eutectic type diagram, with the eutectic composition close to pure SS was obtained. Complementary studies by NMR, X-ray diffraction (XRD) and diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy were performed. A mutual influence was detected in mixtures: the low melting form of SS is favoured at low OLA molar fractions (X(OLA)) and spherulitic structures appear at high X(OLA) and high temperature. Additionally, H-bonding between OLA car...
Source: Chemistry and Physics of Lipids - June 27, 2009 Category: Lipidology Authors: Teixeira AC, Garcia AR, Ilharco LM, Gonçalves da Silva AM, Fernandes AC Tags: Chem Phys Lipids Source Type: journals

Effects of frequency and power of ultrasound on the size reduction of liposome.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The solutions of liposome made of l-alpha-dilauroyl phosphatidylcholine are sonicated at various powers and frequencies (43-480kHz), and the resultant change in the size of liposome is measured by the dynamic light scattering method. The ultrasonic power dissipated into the solution is determined by the calorimetric method in order to compare the effects of ultrasound of different frequencies. The faster reduction of the mean size of liposome is achieved at the lower frequency. Comparing at the same frequency and total energy, short-time irradiation of strong ultrasound is more efficient than long-time irradiation of w...
Source: Chemistry and Physics of Lipids - June 27, 2009 Category: Lipidology Authors: Yamaguchi T, Nomura M, Matsuoka T, Koda S Tags: Chem Phys Lipids Source Type: journals

Effects of ether vs. ester linkage on lipid bilayer structure and water permeability.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The structure and water permeability of bilayers composed of the ether-linked lipid, dihexadecylphosphatidylcholine (DHPC), were studied and compared with the ester-linked lipid, dipalmitoylphosphaditdylcholine (DPPC). Wide angle X-ray scattering on oriented bilayers in the fluid phase indicate that the area per lipid A is slightly larger for DHPC than for DPPC. Low angle X-ray scattering yields A=65.1A(2) for DHPC at 48 degrees C. LAXS data provide the bending modulus, K(C)=4.2x10(-13)erg, and the Hamaker parameter H=7.2x10(-14)erg for the van der Waals attractive interaction between neighboring bilayers. For the low ...
Source: Chemistry and Physics of Lipids - June 27, 2009 Category: Lipidology Authors: Guler SD, Ghosh DD, Pan J, Mathai JC, Zeidel ML, Nagle JF, Tristram-Nagle S Tags: Chem Phys Lipids Source Type: journals

Membrane permeabilization by Islet Amyloid Polypeptide.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Membrane permeabilization by Islet Amyloid Polypeptide (IAPP) is suggested to be the main mechanism for IAPP-induced cytotoxicity and death of insulin-producing beta-cells in type 2 diabetes mellitus (T2DM). The insoluble fibrillar IAPP deposits (amyloid) present in the pancreas of most T2DM patients are not the primary suspects responsible for permeabilization of beta-cell membranes. Instead, soluble IAPP oligomers are thought to be cytotoxic by forming membrane channels or by inducing bilayer disorder. In addition, the elongation of IAPP fibrils at the membrane, but not the fibrils themselves, could cause membrane di...
Source: Chemistry and Physics of Lipids - June 27, 2009 Category: Lipidology Authors: Engel MF Tags: Chem Phys Lipids Source Type: journals

The binary phase behavior of 1, 3-dipalmitoyl-2-stearoyl-sn-glycerol and 1, 2-dipalmitoyl-3-stearoyl-sn-glycerol.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The binary phase behavior of purified 1, 3-dipalmitoyl-2-stearoyl-sn-glycerol (PSP) and 1, 2-dipalmitoyl-3-stearoyl-sn-glycerol (PPS) was investigated at a very slow (0.1 degrees C/min) and a relatively fast (3.0 degrees C/min) cooling rate. Mixtures with molar fractions of 0.1 increments were studied in terms of melting and crystallization, polymorphism, solid fat content (SFC), hardness and microstructure. Only the alpha-form of a double chain length (DCL) structure was detected for all mixtures in both experiments. The kinetic phase diagram, constructed using heating DSC thermograms, displayed two distinct behaviors...
Source: Chemistry and Physics of Lipids - June 27, 2009 Category: Lipidology Authors: Boodhoo MV, Bouzidi L, Narine SS Tags: Chem Phys Lipids Source Type: journals

First total synthesis and antiprotozoal activity of (Z)-17-methyl-13-octadecenoic acid, a new marine fatty acid from the sponge Polymastia penicillus.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The first total synthesis for the (Z)-17-methyl-13-octadecenoic acid was accomplished in seven steps and in a 45% overall yield. The use of (trimethylsilyl)acetylene was key in the synthesis. Based on a previous developed strategy in our laboratory the best synthetic route towards the title compound was first acetylide coupling of (trimethylsilyl)acetylene to the long-chain protected 12-bromo-1-dodecanol followed by a second acetylide coupling to the short-chain 3-methyl-1-bromobutane, which resulted in higher yields. Complete spectral data is also presented for the first time for this recently discovered fatty acid. T...
Source: Chemistry and Physics of Lipids - June 11, 2009 Category: Lipidology Authors: Carballeira NM, Montano N, Balaña-Fouce R, Prada CF Tags: Chem Phys Lipids Source Type: journals

A Comparison of the Packing Behavior of Egg Phosphatidylcholine with Cholesterol and Biogenically Related Sterols in Langmuir Monolayer Films.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cholesterol and selected derivatives were studied as mixed Langmuir monolayers with egg phosphatidylcholine (PC). As an extension of our earlier work, which employed binary sterol/PC mixtures, here we examined ternary mixed monolayers containing cholesterol along with an alternate sterol and PC in different molar ratios, using pressure-area isotherms. The ternary systems behaved similarly to the binary sterol/PC systems reported previously, with similar condensation noted for the sterol/PC films. To better understand how variations in sterol structure affect sterol packing in such membrane monolayers, binary mixtures c...
Source: Chemistry and Physics of Lipids - June 10, 2009 Category: Lipidology Authors: Lintker KB, Kpere-Daibo P, Fliesler SJ, Serfis AB Tags: Chem Phys Lipids Source Type: journals

The solid-liquid phase diagrams of binary mixtures of consecutive, even saturated fatty acids.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
For the first time, the solid-liquid phase diagrams of five binary mixtures of saturated fatty acids are here presented. These mixtures are formed of caprylic acid (C(8:0))+capric acid (C(10:0)), capric acid (C(10:0))+lauric acid (C(12:0)), lauric acid (C(12:0))+myristic acid (C(14:0)), myristic acid (C(14:0))+palmitic acid (C(16:0)) and palmitic acid (C(16:0))+stearic acid (C(18:0)). The information used in these phase diagrams was obtained by differential scanning calorimetry (DSC), X-ray diffraction (XRD), FT-Raman spectrometry and polarized light microscopy, aiming at a complete understanding of the phase diagrams ...
Source: Chemistry and Physics of Lipids - June 8, 2009 Category: Lipidology Authors: Costa MC, Sardo M, Rolemberg MP, Coutinho JA, Meirelles AJ, Ribeiro-Claro P, Krähenbühl MA Tags: Chem Phys Lipids Source Type: journals

A comparative study of the effect of cholesterol on bicelle model membranes using X-band and Q-band EPR spectroscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
X-band and Q-band electron paramagnetic resonance (EPR) spectroscopic techniques were used to investigate the structure and dynamics of cholesterol containing phospholipid bicelles based upon molecular order parameters (S(mol)), orientational dependent hyperfine splittings and line shape analysis of the corresponding EPR spectra. The nitroxide spin-label 3-beta-doxyl-5-alpha-cholestane (cholestane) was incorporated into DMPC/DHPC bicelles to report the alignment of bicelles in the static magnetic field. The influence of cholesterol on aligned phospholipid bicelles in terms of ordering, the ease of alignment, phase tran...
Source: Chemistry and Physics of Lipids - June 5, 2009 Category: Lipidology Authors: Ghimire H, Inbaraj JJ, Lorigan GA Tags: Chem Phys Lipids Source Type: journals

Coarse-grained modeling of lipids.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Molecular modeling of phospholipids on many scales has progressed significantly over the last years. Here we review several membrane models on intermediate to large length scales restricting ourselves to particle based coarse-grained models with implicit and explicit solvent. We explain similarities and differences as well as their connection to experiments and fine-grained models. We neglect any field descriptions on larger scales. We discuss then a few examples where we focus on studies of lipid phase behavior as well as supported lipid bilayers as these examples can only be meaningfully studied using large-scale mod...
Source: Chemistry and Physics of Lipids - May 31, 2009 Category: Lipidology Authors: Bennun SV, Hoopes MI, Xing C, Faller R Tags: Chem Phys Lipids Source Type: journals

Growth and shape transformations of giant phospholipid vesicles upon interaction with an aqueous oleic acid suspension.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The interaction of two types of vesicle systems was investigated: micrometer-sized, giant unilamellar vesicles (GUVs) formed from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and submicrometer-sized, large unilamellar vesicles (LUVs) formed from oleic acid and oleate, both in a buffered aqueous solution (pH 8.8). Individual POPC GUVs were transferred with a micropipette into a suspension of oleic acid/oleate LUVs, and the shape changes of the GUVs were monitored using optical microscopy. The behavior of POPC GUVs upon transfer into a 0.8mM suspension of oleic acid, in which oleic acid/oleate forms vesicular ...
Source: Chemistry and Physics of Lipids - May 31, 2009 Category: Lipidology Authors: Peterlin P, Arrigler V, Kogej K, Svetina S, Walde P Tags: Chem Phys Lipids Source Type: journals

Absolute configuration of ceriporic acids, the iron redox-silencing metabolites produced by a selective lignin-degrading fungus, Ceriporiopsis subvermispora.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ceriporic acids are a class of alk(en)ylitaconic acids produced by a selective lignin-degrading fungus, Ceriporiopsis subvermispora. The unique function of alkylitaconic acid is the redox silencing of the Fenton reaction system by inhibiting reduction of Fe(3+). Ceriporic acids have an asymmetric centre at carbon-3, but absolute configuration has not been determined. We have isolated a series of ceriporic acids from the cultures of C. subvermispora, and measured their NMR spectra using a chiral shift reagent. In comparison with NMR spectra of (R)-(-)- and (S)-(+)-methylsuccinic acid and those of natural and chemically ...
Source: Chemistry and Physics of Lipids - May 31, 2009 Category: Lipidology Authors: Nishimura H, Murayama K, Watanabe T, Honda Y, Watanabe T Tags: Chem Phys Lipids Source Type: journals

Effect of NaCl and CaCl(2) on the lateral diffusion of zwitterionic and anionic lipids in bilayers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The influence of addition of NaCl or CaCl(2) (0.3 and 0.1M, respectively) on the lateral diffusion coefficient (D(L)) of dioleoylphosphatidylcholine (DOPC) or dioleoylphosphatidylglycerol (DOPG) was measured by the pulsed field gradient NMR technique. D(L) of DOPC was unaffected, whereas the DOPG diffusion decreased with salt concentration. (23)Na NMR quadrupole splittings of DOPG between 20 and 60 degrees C and added NaCl between 0 and 15wt% decreased only slightly with salt content, but increased with increasing temperature. Similar results were obtained for palmitoyloleoylphosphatidylglycerol, in which the palmitoyl...
Source: Chemistry and Physics of Lipids - May 31, 2009 Category: Lipidology Authors: Filippov A, Orädd G, Lindblom G Tags: Chem Phys Lipids Source Type: journals

Fe2+ and Fe3+ initiated peroxidation of sonicated and non-sonicated liposomes made of retinal lipids in different aqueous media.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Retina is highly susceptible to oxidative damage due to its high content of polyunsaturated fatty acids (PUFAs), mainly docosahexaenoic acid (22:6 n3). Lipid peroxidation process is thought to be involved in many physiological and pathological events. Many model membranes can be used to learn more about issues that cannot be studied in biological membranes. Sonicated liposomes (SL) and non-sonicated liposomes (NSL) prepared with lipids isolated from bovine retina and characterized by dynamic light-scattering, were submitted to lipid peroxidation, under air atmosphere at 22 degrees C, with Fe(2+) or Fe(3+) as initiator,...
Source: Chemistry and Physics of Lipids - May 31, 2009 Category: Lipidology Authors: Fagali N, Catalá A Tags: Chem Phys Lipids Source Type: journals

Bipolar tetraether archaeosomes exhibit unusual stability against autoclaving as studied by dynamic light scattering and electron microscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The stability of liposomes made of the polar lipid fraction E (PLFE) isolated from the thermoacidophilic archaeon Sulfolobus acidocaldarius against autoclaving has been studied by using dynamic light scattering and transmission electron microscopy. PLFE lipids have structures distinctly different from those derived from eukaryotes and prokaryotes. PLFE lipids are bipolar tetraether molecules and may contain up to four cyclopentane rings in each of the two dibiphytanyl chains. In the pH range 4-10, PLFE-based archaeosomes, with and without polyethyleneglycol- and maleimide-lipids, are able to retain vesicle size, size d...
Source: Chemistry and Physics of Lipids - May 31, 2009 Category: Lipidology Authors: Brown DA, Venegas B, Cooke PH, English V, Chong PL Tags: Chem Phys Lipids Source Type: journals