MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Chemistry and Physics of Lipids' source. Tue, 07 Feb 2012 05:19:53 +0100 http://www.medworm.com/index.php?rid=5578146&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22227108%26dopt%3DAbstract Authors: Varga Z, Wacha A, Vainio U, Gummel J, Narayanan T, Bóta A Abstract Synchrotron small-angle X-ray scattering analysis of the bilayer structure of a pharmacologically relevant sterically stabilized liposome system is presented. Describing the electron density profile of the bilayer with the superposition of Gaussian functions, the contribution of the poly(ethylene glycol) (PEG) layers to the total electron density was identified. The changes in the thickness of the PEG layer as well as the distribution of the PEG chains among the outer and inner leaflets of the bilayers were followed by changing the molar ratio of the PEG-lipid and the molar weight of the PEG molecule. PMID: 22227108 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5578146 Tue, 27 Dec 2011 05:00:00 +0100 5578146 http://www.medworm.com/index.php?rid=5578145&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22227109%26dopt%3DAbstract Authors: Takahashi H, Hayakawa T, Murate M, Greimel P, Nagatsuka Y, Kobayashi T, Hirabayashi Y Abstract Phosphatidylglucoside (PtdGlc) is a unique glyco-glycerophospholipid that is found in both bacterial and mammalian cells. The discovery of PtdGlc in mammalian cells is relatively recent (Nagatsuka et al., 2001). Chemical structural analysis of the PtdGlc found in mammalian organs and cultured cells showed that PtdGlc is composed exclusively of a single pair of saturated fatty acid chains; the sn-1 chain is stearic acid (C18:0) and the sn-2 chain is arachidic acid (C20:0). PtdGlc forms distinct domains, which are different from cholesterol-based sphingolipid domains, on the outer leaflet of the plasma membrane. In this review, we summarize recent studies of PtdGlc. Special attenti... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5578145 Tue, 27 Dec 2011 05:00:00 +0100 5578145 http://www.medworm.com/index.php?rid=5578144&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22227110%26dopt%3DAbstract We examined lipid domain formation in biomimetic Escherichia coli membranes composed of phosphatidylethanolamine and phosphatidylglycerol in the absence and presence of 1% and 5% (mol/mol) membrane multidrug resistance protein, EmrE. Monolayer isotherms demonstrated protein insertion into the lipid monolayer. Subsequently, Brewster angle microscopy was applied to image domains in lipid matrices and lipid-protein mixtures. The images showed a concentration dependent impact of the protein on lipid domain size and shape and more interestingly distinct coexisting protein clusters. Whereas lipid domains varied in size (14-47μm), protein clusters exhibited a narrow size distribution (2.6-4.8μm) suggesting a non-random process of cluster formation. A 3-D display clearly indicates that these pro... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5578144 Tue, 27 Dec 2011 05:00:00 +0100 5578144 http://www.medworm.com/index.php?rid=5578147&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222463%26dopt%3DAbstract This report focuses on studies of lipid peroxidation products reactivity towards the side chains of cysteine, histidine, and lysine residues in structurally unordered peptides. Thus we have analyzed linoleic acid peroxidation products (LaPP) obtained by incubating 1-palmitoyl-2-linoleoyl-sn-glycerophosphatidylcholine (PLPC) overnight with or without H(2)O(2) in the presence or absence of CuCl. In total, 55 different LaPP were identified with 26 containing reactive carbonyl groups. The strongest oxidation conditions (H(2)O(2) and Cu(I), i.e. a Fenton-like reagent) yielded 51 LaPP, whereas air oxidation produced only 12 LaPP. Independent of the oxidation conditions, around half of all LaPP were short-chain (oxidative cleavage) and the others long-chain (oxygen addition) PLPC oxidation produc... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5578147 Fri, 23 Dec 2011 05:00:00 +0100 5578147 http://www.medworm.com/index.php?rid=5560056&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22209921%26dopt%3DAbstract In this study, the reaction products of [60]fullerene (C(60)) during the autoxidation of methyl linoleate (MeL) were isolated and their structures were characterized. MeL containing 0.1mol% C(60) was autoxidized at 60°C in bulk phase and two reaction products of C(60), 1 and 2, were obtained. The structure of 1 was the addition products of C(60) with 9-peroxyl-10-alkyl radicals of methyl (11E)-13-hydroperoxy-11-octadecaenoate (1a and 1b) and with 12-alkyl-13-peroxyl radicals of methyl (10E)-9-hydroperoxy-10-octadecaenoate (1c and 1d). 2 was a mixture of the addition products of C(60) with 9,11-dialkyl radicals of methyl 9,12-octadecadienoate (2a) and with 11,13-dialkyl radicals of methyl 9,12-octadecadienoate (2b). When MeL containing 0.1mol% C(60) was autoxidized at 60°C under air-suffi... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5560056 Thu, 22 Dec 2011 05:00:00 +0100 5560056 http://www.medworm.com/index.php?rid=5560054&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22209923%26dopt%3DAbstract EFFECT OF HEAD GROUP AND CURVATURE ON BINDING OF THE ANTIMICROBIAL PEPTIDE TRITRPTICIN TO LIPID MEMBRANES. Chem Phys Lipids. 2011 Dec 22; Authors: Bozelli JC, Sasahara ET, Pinto MR, Nakaie CR, Schreier S Abstract In this work we examine the interaction between the 13-residue cationic antimicrobial peptide (AMP) tritrpticin (VRRFPWWWPFLRR, TRP3) and model membranes of variable lipid composition. The effect on peptide conformational properties was investigated by means of CD (circular dichroism) and fluorescence spectroscopies. Based on the hypothesis that the antibiotic acts through a mechanism involving toroidal pore formation, and taking into account that models of toroidal pores imply the formation of positive curvature, we used large unilamellar vesicles (LUV) to mimic t... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5560054 Thu, 22 Dec 2011 05:00:00 +0100 5560054 http://www.medworm.com/index.php?rid=5560057&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22206709%26dopt%3DAbstract Authors: Milosevits G, Rozsnyay Z, Kozma GT, Milosevits J, Tömöry G, Robotka H, Rosivall L, Szebeni J Abstract In an attempt to develop a quantitative assay for supravesicular structures (SVS) - such as aggregates, fused liposomes or solid lipid particles - in liposome preparations, forward vs. side scattering of liposomal doxorubicin (Doxil/Caelyx) was analyzed by flow cytometry. Based on calibration with fluorescent latex beads, the size resolution was between about 500 and 1000nm. Caelyx, just as structurally matched empty liposomes (Doxebo) produced dot plots clearly distinguishable from background, suggesting the presence of SVS in the above size region. A comparison of gated areas on the scattergrams obtained for different Caelyx preparations showed differences between curr... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5560057 Tue, 20 Dec 2011 05:00:00 +0100 5560057 http://www.medworm.com/index.php?rid=5560055&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22209922%26dopt%3DAbstract Authors: Barroso RP, Perez KR, Cuccovia IM, Teresa Lamy M Abstract Aqueous dispersions of dimyristoyl phosphatidylglycerol (DMPG), at low ionic strength, display uncommon thermal behavior. Models for such behavior need to assign a form to the lipid aggregate. Although most studies accept the presence of lipid vesicles in the lipid gel and fluid phases, this is still controversial. With electron spin resonance (ESR) spectra of spin labels incorporated into DMPG aggregates, quantification of [(14)C]sucrose entrapped by the aggregates, and viscosity measurements, we demonstrate the existence of leaky vesicles in dispersions of DMPG at low ionic strength, in both gel and fluid phases of the lipid. As a control system, the ubiquitous lipid dimyristoyl phosphatidylcholine (DMPC) was used... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5560055 Tue, 20 Dec 2011 05:00:00 +0100 5560055 http://www.medworm.com/index.php?rid=5549826&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200532%26dopt%3DAbstract Authors: Smith EA, Wang W, Dea PK Abstract Unlike the parent phospholipid, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), the monofluorinated analog, 1-palmitoyl-2-(16-fluoropalmitoyl)sn-glycero-3-phosphocholine (F-DPPC), spontaneously forms an interdigitated gel phase (L(β)I) below the main transition temperature (T(m)). We have examined the effects of introducing cholesterol to F-DPPC and 1:1 F-DPPC/DPPC membranes using a combination of DSC, optical density, fluorescence intensity and polarization, (31)P NMR, and X-ray diffraction techniques. Cholesterol increases the fluidity of the gel phase, broadens the main transition, and decreases the main transition enthalpy. However, these results also reveal that there is an unusually large degree of phase coexistence between the ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5549826 Fri, 16 Dec 2011 05:00:00 +0100 5549826 http://www.medworm.com/index.php?rid=5549829&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22197684%26dopt%3DAbstract Authors: Laszlo JA, Evans KO, Compton DL, Appell M Abstract Antioxidants have critical roles in maintaining cellular homeostasis and disease-state prevention. The multi-functional agent α-lipoic acid offers numerous beneficial effects to oxidatively stressed tissues. α-Lipoic acid was enzymatically incorporated into a triglyceride in conjunction with oleic acid, creating lipoyl dioleoylglycerol, and chemically reduced to form dihydrolipoyl dioleoylglycerol. The triglyceride forms of lipoic acid stabilized dioleoylphosphatidylcholine unilamellar liposomal vesicles, as judged by calcein-cobalt leakage. Stabilization resulted from increased packing density of phospholipid acyl chains. Scavenging activity against the 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) radical was mo... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5549829 Wed, 14 Dec 2011 05:00:00 +0100 5549829 http://www.medworm.com/index.php?rid=5549828&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22197685%26dopt%3DAbstract Authors: Ahmed M, Moussa M, Goldberg SN Abstract Minimally invasive image-guided tumor ablation using short duration heating via needle-like applicators using energies such as radiofrequency or microwave has seen increasing clinical use to treat focal liver, renal, breast, bone, and lung tumors. Potential benefits of this thermal therapy include reduced morbidity and mortality compared to standard surgical resection and ability to treat non-surgical patients. However, improvements to this technique are required as achieving complete ablation in many cases can be challenging particularly at margins of tumors>3cm in diameter and adjacent to blood vessels. Thus, one very promising strategy has been to combine thermal tumor ablation with adjuvant nanoparticle-based chemotherapy agen... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5549828 Wed, 14 Dec 2011 05:00:00 +0100 5549828 http://www.medworm.com/index.php?rid=5549827&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22197998%26dopt%3DAbstract Authors: Semenova AA, Chugunov AO, Dubovskii PV, Chupin VV, Volynsky PE, Boldyrev IA Abstract In the course of structure-function investigations of lipids a phosphatidylcholine molecule with short and rigid tails, di-2,4-hexadienoylphosphatidylcholine (DiSorbPC), was synthesized and studied in comparison with its saturated analog, dihexanoylphosphatidylcholine (DHPC). Conjugated double bonds in the acyl chains in DiSorbPC reduce considerably the number of possible conformers of the lipid within an aggregate. This leads to impaired packing of unsaturated acyl chains and thus, to a surprisingly high (115Å(2)) area per molecule for DiSorbPC at the air-water interface and failure to form micelles of regular size and shape. Details on DiSorbPC aggregation and packing provided by a set... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5549827 Wed, 14 Dec 2011 05:00:00 +0100 5549827 http://www.medworm.com/index.php?rid=5534537&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22182491%26dopt%3DAbstract Authors: Sheikh K, Giordani C, McManus JJ, Hovgaard MB, Jarvis SP Abstract Membrane interactions with β-amyloid peptides are implicated in the pathology of Alzheimer's disease and cholesterol has been shown to be key modulator of this interaction, yet little is known about the mechanism of this interaction. Using atomic force microscopy, we investigated the interaction of monomeric Aβ(1-40) peptides with planar mica-supported bilayers composed of DOPC and DPPC containing varying concentrations of cholesterol. We show that below the bilayer melting temperature, Aβ monomers adsorb to, and assemble on, the surface of DPPC bilayers to form layers that grow laterally and normal to the bilayer plane. Above the bilayer melting temperature, we observe protofibril formation. In contrast,... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5534537 Fri, 09 Dec 2011 05:00:00 +0100 5534537 http://www.medworm.com/index.php?rid=5534538&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22178158%26dopt%3DAbstract Authors: Rowland MM, Gong D, Bostic HE, Lucas N, Cho W, Best MD Abstract Signaling lipids control many of the most important biological pathways, typically by recruiting cognate protein binding targets to cell surfaces, thereby regulating both their function and subcellular localization. A critical family of signaling lipids is that of the phosphatidylinositol polyphosphates (PIP(n)s), which is composed of seven isomers that vary based on phosphorylation pattern. A key protein that is activated upon PIP(n) binding is Akt, which then plays important roles in regulating the cell cycle, and is thus aberrant in disease. Characterization of protein-PIP(n) binding interactions is hindered by the complexity of the membrane environment and of the PIP(n) structures. Herein, we describe two ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5534538 Thu, 08 Dec 2011 05:00:00 +0100 5534538 http://www.medworm.com/index.php?rid=5534539&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22173018%26dopt%3DAbstract Authors: Ionov M, Wróbel D, Gardikis K, Hatziantoniou S, Demetzos C, Majoral JP, Klajnert B, Bryszewska M Abstract Large unilamellar liposomes and multilamellar vesicles consisting of DMPC interacted with cationic phosphorus-containing dendrimers CPDs G3 and G4. DSC and ζ-potential measurements have shown that liposomal-dendrimeric molecular recognition probably occurs due to the interaction between the complementary surface groups. Calorimetric studies indicate that the enthalpy of the transition of the lipids that interact with CPDs is dependent on the dendrimers generation. These results can be used in order to rationally design mixed modulatory liposomal locked-in dendrimeric, drug delivery nano systems. PMID: 22173018 [PubMed - as supplied by publisher] (Source: Chemistr... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5534539 Wed, 07 Dec 2011 05:00:00 +0100 5534539 http://www.medworm.com/index.php?rid=5534540&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22155692%26dopt%3DAbstract Authors: Patil YP, Kumbhalkar MD, Jadhav S Abstract Unilamellar vesicle populations having a narrow size distribution and mean radius below 100nm are preferred for drug delivery applications. In the present work, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) was used to prepare giant unilamellar vesicles (GUVs) by electroformation and multilamellar vesicles (MLVs) by thin film hydration. Our experiments show that in contrast to MLVs, a single-pass extrusion of GUVs through track-etched polycarbonate membranes at moderate pressure differences is sufficient to produce small liposomes having low polydispersity index. Moreover, we observe that the drug encapsulating potential of extruded liposomes obtained from GUVs is significantly higher compared to liposomes prepared by extrusi... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5534540 Sat, 03 Dec 2011 05:00:00 +0100 5534540 http://www.medworm.com/index.php?rid=5534541&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22155352%26dopt%3DAbstract In conclusion, this method which combined small volume needing size-exclusion fast protein liquid chromatography and fluorescence-based lipids measurement, provided a simple, efficient, integrity and reproducible procedure for determining serum lipoprotein and lipids profiles in micro-liter scale levels. It becomes possible that determination of lipoprotein profiles and gaining information of lipids in different lipoproteins can be accomplished simultaneously. PMID: 22155352 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5534541 Thu, 01 Dec 2011 05:00:00 +0100 5534541 http://www.medworm.com/index.php?rid=5493230&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22133728%26dopt%3DAbstract Authors: Eleršič K, Pavlič JI, Iglič A, Vesel A, Mozetič M Abstract Liposomes are one of the most promising biomaterial carriers to deliver DNA,(1) proteins, drugs and medicine in human bodies. However, artificially formed liposomes have to satisfy some crucial functions such as: (i) to efficiently carry drugs to targeted systems, (ii) to be biologically stable until they are removed from human body, (iii) to be biodegradable, and (iv) to be sufficiently small in size for effective drug delivery. Here, we report an efficient and novel method to simultaneously manufacture and incorporate super-paramagnetic iron-oxide nanoparticles (efficient target finder in the presence of external magnetic field) into the liposome's interior and its bilayer. In this technique, we use electric... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5493230 Wed, 23 Nov 2011 05:00:00 +0100 5493230 http://www.medworm.com/index.php?rid=5493229&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22133729%26dopt%3DAbstract Authors: Mazor S, Vanounou S, Fishov I Abstract We take the advantage of pyrene's unique spectral properties as a reliable polarity indicator to monitor pyrene localizations in the membrane depth by using wavelength selective fluorescence approach. We show that fine structure of pyrene fluorescence emission spectra and excimerization rate in model and native phospholipid membranes depend on the excitation wavelength. This phenomenon is not observed in neat solvents. In membranes, the dependence on the excitation wavelength reflects selective excitation of pyrene molecules located close to the membrane-water polar interface, or deep in the hydrophobic core of the membrane, verified with the aid of pyrene derivatives of fatty acids of various lengths. PMID: 22133729 [PubMed - as ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5493229 Wed, 23 Nov 2011 05:00:00 +0100 5493229 http://www.medworm.com/index.php?rid=5493232&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119850%26dopt%3DAbstract Authors: Bouchet AM, Lairión F, Ruysschaert JM, Lensink MF Abstract Arginine-rich peptides receive increased attention due to their capacity to cross different types of membranes and to transport cargo molecules inside cells. Even though peptide-induced destabilization has been investigated extensively, little is known about the peptide side-chain and backbone orientation with respect to the bilayer that may contribute to a molecular understanding of the peptide-induced membrane perturbations. The main objective of this work is to provide a detailed description of the orientation of arginine peptides in the lipid bilayer of PC and negatively charged PG liposomes using ATR-IR spectroscopy and molecular modeling, and to relate these orientational preferences to lipid bilayer destabi... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5493232 Sat, 19 Nov 2011 05:00:00 +0100 5493232 http://www.medworm.com/index.php?rid=5493231&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119851%26dopt%3DAbstract Authors: Goldberg R, Klein J Abstract In this paper we review recent work (Goldberg et al., 2011a,b) on a new use for phosphatidylcholine liposomes: as ultra-efficient boundary lubricants at up to the highest physiological pressures. Using a surface force balance, we have measured the normal and shear interactions as a function of surface separation between layers of hydrogenated soy phophatidylcholine (HSPC) small unilamellar vesicles (SUVs) adsorbed from dispersion, at both pure water and physiologically high salt concentrations of 0.15M NaNO(3). Cryo-Scanning Electron Microscopy shows each surface to be coated by a close-packed HSPC-SUV layer with an over-layer of liposomes on top. The shear forces reveal strikingly low friction coefficients down to 2×10(-5) in pure water syste... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5493231 Sat, 19 Nov 2011 05:00:00 +0100 5493231 http://www.medworm.com/index.php?rid=5493235&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119325%26dopt%3DAbstract Authors: Bouzidi L, Narine SS Abstract The kinetic phase behavior and phase transformation paths of purified tristearoylglycerol (SSS), 3-palmitoyl-1,2-distearoyl-sn-glycerol (PSS) and 1,2-dipalmitoyl-3-stearoyl-sn-glycerol (PPS) were investigated in terms of polymorphism, crystallization and melting. The details of the phase transformation paths were obtained using the heating cycles of two sets of experiments: (a) cooling rate was varied and heating rate fixed and (b) cooling rate was fixed and heating rate varied. Kinetic effects were manifest in all measured properties, underscoring the complexity of the phase transformation paths for each TAG, and the intricate thermodynamics-molecular relationships. For the first time, XRD data obtained for SSS, PSS and PPS TAGs, cooled at ra... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5493235 Fri, 18 Nov 2011 05:00:00 +0100 5493235 http://www.medworm.com/index.php?rid=5493233&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119326%26dopt%3DAbstract Authors: Bouzidi L, Narine SS Abstract The phase behavior of 1-palmitoyl-2,3-distearoyl-sn-glycerol (PSS)/tristearoylglycerol (SSS) binary system was investigated in terms of polymorphism, crystallization and melting behavior, microstructure and solid fat content (SFC) using widely different constant cooling rates. Kinetic phase diagrams were experimentally determined from the DSC heating thermograms and analyzed using a thermodynamic model to account for non-ideality of mixing. The kinetic phase diagram presented a typical eutectic behavior with a eutectic point at the 0.5(PSS) mixture with a probable precipitation line from 0.5(PSS) to 1.0(PSS), regardless of the rate at which the sample was cooled. The eutectic temperature decreased only slightly with increasing cooling rate. PS... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5493233 Fri, 18 Nov 2011 05:00:00 +0100 5493233 http://www.medworm.com/index.php?rid=5493236&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22115831%26dopt%3DAbstract Authors: Bouzidi L, Li S, Di Biase S, Rizvi SQ, Narine SS Abstract Four pure jojoba wax-like esters (JLEs), having carbon chain length of 36, 40 (two isomers) and 44, were prepared by Steglish esterification of fatty acids (or acid chlorides) with fatty alcohols at room temperature. Calorimetric and diffraction data was used to elucidate the phase behavior of the esters. The primary thermal parameters (crystallization and melting temperatures) obtained from the DSC of the symmetrical molecules correspond well with the carbon numbers of the JLEs. However, the data also suggests that carbon number is not the only factor since the symmetry of the molecule also plays a significant role in the phase behavior. Overall, the JLEs show very little polymorphic activity at the experimental co... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5493236 Wed, 16 Nov 2011 05:00:00 +0100 5493236 http://www.medworm.com/index.php?rid=5493237&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22108318%26dopt%3DAbstract Authors: Takechi Y, Tanaka H, Kitayama H, Yoshii H, Tanaka M, Saito H Abstract Cell-penetrating peptides are arginine- and lysine-rich cationic peptides that can readily enter cells not only by themselves but also carrying other macromolecular cargos. In fact, we have reported that polycationic polymer such as poly-l-lysine (PLL) and poly-l-arginine (PLA) translocate through negatively charged phospholipid liposome membranes. In this work, we made a comparative study of the interaction of PLL or PLA with lipid membranes consisting of negatively charged phospholipids to understand the role of basic amino acid residue (i.e. arginine and lysine) in the membrane-penetrating activity of polypeptides. PLA and PLL translocated into giant unilamellar vesicle composed of soybean phospholipi... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5493237 Sat, 12 Nov 2011 05:00:00 +0100 5493237 http://www.medworm.com/index.php?rid=5493238&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22101108%26dopt%3DAbstract Authors: Marsh D Abstract The chain packing in ordered phases of lipid bilayers can be classified according to wide-angle X-ray diffraction (WAXS). For triclinic (T(‖)) and monoclinic (M(‖)) packing in crystalline L(c) phases, the wide-angle reflections index on an oblique lattice with spacings s(10)≠s(01)≠s(11), and each chain has four nearest neighbours. For orthorhombic (O(⊥)) packing in L(c) phases, and the rotationally symmetric equivalent in metastable low-temperature L(β) phases (mL(β)), the wide-angle reflections index on a centred rectangular lattice with spacings s(20)<s(11), and each chain has four nearest neighbours. For distorted hexagonal packing in the L(c') subgel, and in L(β') gel phases and the metastable low-temperature equivalent (mL(β')), the w... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5493238 Fri, 11 Nov 2011 05:00:00 +0100 5493238 http://www.medworm.com/index.php?rid=5419999&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22062971%26dopt%3DAbstract Authors: Pahari B, Chakrabarty S, Chaudhuri S, Sengupta B, Sengupta PK Abstract Plant flavonoids are emerging as novel therapeutic drugs for free radical mediated diseases, for which cell membranes mainly serve as targets for lipid peroxidation and related deleterious effects. Screening and characterization of these ubiquitous, therapeutically potent polyphenolic compounds require a clear understanding regarding their binding and possible locations in membranes, as well as quantitative estimates of relevant parameters such as partition coefficients, antioxidant and radical scavenging capacities. In this article we present perspectives emphasizing novel uses of the exquisitely sensitive 'two color' intrinsic fluorescence of plant flavonoids (which arise due to highly efficient photo... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5419999 Sat, 29 Oct 2011 04:00:00 +0100 5419999 http://www.medworm.com/index.php?rid=5419997&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22074880%26dopt%3DAbstract In this study, we analysed a series of extracellular lipid-related metabolites produced by the fungus and found that a wide variety of ceriporic acids and fatty acids, including those with odd-numbered and very long-chains, were produced in wood meal cultures. Two new ceriporic acids, (R)-3-[(Z)-tetradec-7-enyl]-itaconic acid and (R)-3-[(Z)-tetradec-5-enyl]-itaconic acid, were for the first time identified by dimethyl disulfide derivatisation, followed by GC/EI-MS, (1)H and homonuclear J-resolved 2D NMR and feeding experiments with [(13)C-U] glucose coupled with multiple-stage mass spectrometry. In separation by GC and LC, a reversed correlation of elution sequences between a nonpolar GC column and an ODS-LC column for cis and trans isomers of ω7 and ω9 lipids was found, and the elution ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5419997 Sat, 29 Oct 2011 04:00:00 +0100 5419997 http://www.medworm.com/index.php?rid=5419998&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22064068%26dopt%3DAbstract Authors: Guo ZG, Li C, Zhong JK, Tu Y, Xie D Abstract High-density lipoprotein (HDL) particles are anti-atherosclerotic, by virtue of their functions in reverse cholesterol transportation, anti-inflammation and anti-oxidation. However, recent studies have cast doubt on the cardio-protective role of HDL. Structural modification and composition alteration of HDL due to chronic inflammation and acute phase responses may result in loss of normal biological function and even convert HDL into a pro-inflammatory and pro-oxidative agent. Therefore, the assessment of dysfunctional HDL has become a novel target to investigate the association between HDL and coronary artery disease risk. This review article summarizes the laboratory assessment of dysfunctional HDL. PMID: 22064068 [PubMed ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5419998 Tue, 25 Oct 2011 04:00:00 +0100 5419998 http://www.medworm.com/index.php?rid=5379669&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22027273%26dopt%3DAbstract Authors: Marsh D Abstract X-ray diffraction measurements are available on a wide range of glycolipid multilamellar assemblies in excess water, but not at the defined water contents that are needed to derive bilayer dimensions. For lamellar crystalline phases and gel phases with untilted chains, or where the tilt angle is known, the cross-sectional area per chain from wide-angle diffraction can be used to determine the area per lipid molecule at the bilayer surface. Using the lipid molecular volume from densitometry, it is then possible to obtain the bilayer thickness and hence, from the lamellar repeat spacing, the water layer thickness and degree of hydration of the lipid polar groups. This is done here by using the available data for bilayer-forming diacyl and dialkyl glycosylgly... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5379669 Tue, 18 Oct 2011 04:00:00 +0100 5379669 http://www.medworm.com/index.php?rid=5379668&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22027274%26dopt%3DAbstract Authors: Matsuoka K, Rie E, Yui S, Honda C, Endo K Abstract We used a model intestinal solution to understand the mechanisms of cholesterol lowering by the addition of plant sterols. The experimental results of the competitive solubilization of cholesterol and β-sitosterol in vitro give useful information about these mechanisms. The states of the model intestinal solution as a solubilizer were analyzed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) by changing the number of components, and the bile salt and phosphatidylcholine concentrations. There were aggregates of different sizes: liposomes and mixed micelles depending on their components and concentrations. The maximum solubilization of cholesterol increased from 0.2mM to 1.3mM when adding fatty c... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5379668 Tue, 18 Oct 2011 04:00:00 +0100 5379668 http://www.medworm.com/index.php?rid=5379670&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22024173%26dopt%3DAbstract Authors: Peng A, Pisal DS, Doty A, Balu-Iyer SV Abstract Liposomes consisted of phosphatidylinositol (PI) and phosphatidylcholine (PC) have been utilized as delivery vehicle for drugs and proteins. In the present work, we studied the effect of soy PI on physical properties of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) liposomes such as phase state of lipid bilayer, lipid packing and phase properties using multiple orthogonal biophysical techniques. The 6-dodecanoyl-2-dimethylamino naphthalene (Laurdan) fluorescence studies showed that presence of PI induces the formation of fluid phases in DMPC. Differential scanning calorimetry (DSC), temperature dependent fluorescence anisotropy measurements, and generalized polarization values for Laurdan showed that the presence of as l... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5379670 Mon, 17 Oct 2011 04:00:00 +0100 5379670 http://www.medworm.com/index.php?rid=5379671&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22008630%26dopt%3DAbstract Authors: Guendouzi A, Mekelleche SM Abstract The aim of these works present in this paper consisted in the development and evaluation of quantitative structure property models (QSPR) for the prediction of the melting points of a series constituted by 62 fatty acids. The best multilinear regressions method (MLR) is used to develop models for the prediction of the melting points. The descriptors of the model are selected among an extended set of more than 500 descriptors (constitutional, topological, geometric, quantum chemical and thermodynamic descriptors). Applicability domains were defined and the predictive power was determined using a set of validations The QSPR models are established using the BMLR method implemented in CODESSA software, It turns out that the best QSPR model (... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5379671 Mon, 10 Oct 2011 04:00:00 +0100 5379671 http://www.medworm.com/index.php?rid=5312427&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21982866%26dopt%3DAbstract Authors: Zhao G, Subbaiah PV, Mintzer E, Chiu SW, Jakobsson E, Scott HL Abstract Conjugated linoleic acids (CLA) are found naturally in dairy products. Two isomers of CLA, that differ only in the location of cis and trans double bonds, are found to have distinct and different biological effects. The cis 9 trans 11 (C9T11) isomer is believed to have anti-carcinogenic effects, while the trans 10 cis 12 (T10C12) isomer is believed to be associated with anti-obesity effects. In this paper we extend earlier molecular dynamics (MD) simulations of pure CLA-phosphatidylcholine bilayers to investigate the comparative effects of cholesterol on bilayers composed of the two respective isomers. Simulations of phosphatidylcholine lipid bilayers in which the sn-2 chains contained one of the two i... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5312427 Sat, 01 Oct 2011 04:00:00 +0100 5312427 http://www.medworm.com/index.php?rid=5279898&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21946022%26dopt%3DAbstract Authors: Cantù L, Del Favero E, Sonnino S, Prinetti A Abstract Cellular membranes are highly organized structures with multiple and multi-dimensional levels of order where lipid components are active players. The lipid role is especially evident in rafts, where lipid-driven collective interaction dictates the local structure of a membrane. However, lipids play as well other roles in many aspects of membrane mechanics and function. In this review, we would like to re-focus the attention of the readers on the importance of gangliosides in organizing the fine structure of cellular membranes, in lateral and transverse directions. Important biological events are likely to be affected such as the dynamic control of the shape of specialized plasma membrane areas and of the intracellular ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5279898 Mon, 19 Sep 2011 04:00:00 +0100 5279898 http://www.medworm.com/index.php?rid=5279905&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21939642%26dopt%3DAbstract We describe herein the development of a more sensitive and complementary "fluorescence technique" for this purpose and its application to liposomes, bioliposomes and erythrocyte ghosts. This technique is based on the observation in selected compounds of an excellent correlation between the emission wavelength (λ(em)) and Dimroth-Reichardt E(T)(30) polarity parameter for the solvent in which the fluorescence emission spectrum was obtained. PMID: 21939642 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5279905 Fri, 16 Sep 2011 04:00:00 +0100 5279905 http://www.medworm.com/index.php?rid=5279900&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21945565%26dopt%3DAbstract Authors: Riedl S, Zweytick D, Lohner K Abstract Although much progress has been achieved in the development of cancer therapies in recent decades, problems continue to arise particularly with respect to chemotherapy due to resistance to and low specificity of currently available drugs. Host defense peptides as effector molecules of innate immunity represent a novel strategy for the development of alternative anticancer drug molecules. These cationic amphipathic peptides are able to discriminate between neoplastic and non-neoplastic cells interacting specifically with negatively charged membrane components such as phosphatidylserine (PS), sialic acid or heparan sulfate, which differ between cancer and non-cancer cells. Furthermore, an increased number of microvilli has been found on... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5279900 Fri, 16 Sep 2011 04:00:00 +0100 5279900 http://www.medworm.com/index.php?rid=5279899&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21945566%26dopt%3DAbstract Authors: Russell AL, Kennedy AM, Spuches AM, Gibson WS, Venugopal D, Klapper D, Srouji AH, Bhonsle JB, Hicks RP Abstract Circular Dichroism (CD), isothermal calorimetry (ITC) and calcein fluorescence leakage experiments were conducted to provide insight into the mechanisms of binding of a series of antimicrobial peptides containing unnatural amino acids (Ac-XF-Tic-Oic-XK-Tic-Oic-XF-Tic-Oic-XK-Tic-KKKK-CONH(2)) to zwitterionic and anionic micelles, SUVs and LUVs; where X (Spacer# 1) is either Gly, β-Ala, Gaba or 6-aminohexanoic acid. It is the intent of this investigation to correlate these interactions with the observed potency and selectivity against several different strains of bacteria. The CD spectra of these compounds in the presence of zwitterionic DPC micelles and anionic S... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5279899 Fri, 16 Sep 2011 04:00:00 +0100 5279899 http://www.medworm.com/index.php?rid=5246918&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21925488%26dopt%3DAbstract Authors: Beker BY, Bakır T, Sönmezoğlu I, Imer F, Apak R Abstract Antioxidants are compounds that can delay or inhibit lipid oxidation. The peroxidation of linoleic acid (LA) in the absence and presence of Cu(II) ion-ascorbate combinations was investigated in aerated and incubated emulsions at 37°C and pH 7. LA peroxidation induced by copper(II)-ascorbic acid system followed first order kinetics with respect to hydroperoxides concentration. The extent of copper-initiated peroxide production in a LA system assayed by ferric thiocyanate method was used to determine possible antioxidant and prooxidant activities of the added flavonoids. The effects of three different flavonoids of similar structure, i.e. quercetin (QR), morin (MR) and catechin (CT), as potential antioxidant protec... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5246918 Fri, 09 Sep 2011 04:00:00 +0100 5246918 http://www.medworm.com/index.php?rid=5230138&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21920353%26dopt%3DAbstract We present new and simple method for formation of giant unilamellar vesicles (GUVs) in high ionic strength solutions, such as phosphate buffered saline (PBS). Mechanoformation method is an alternative method to electroformation method. The advantage of the mechanoformation procedure is that there are no limitations with respect to the ionic strength of the aqueous solutions, because there is no applied electric potential thus no current flow through the formation cell and no electrolysis is induced. PMID: 21920353 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5230138 Tue, 06 Sep 2011 04:00:00 +0100 5230138 http://www.medworm.com/index.php?rid=5175802&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21872581%26dopt%3DAbstract In this study, the phase structure of the lipid mixtures that contained two or three lipids was investigated using three different methods: dynamic light scattering, (1)H NMR, and microfluidity measurements with fluorescence probes. Three lipids that are commonly present in imaging agents (DPPC, DPPE-PEG, and DPPA) were used. Two types of systems, two-lipid model systems and simulated imaging systems were investigated. The results show that liposomes were the dominant aggregates in all the samples studied. The polar PEG side chains from the PEGylated lipid lead to the formation of micelles and micellar aggregates in small sizes. In the ternary lipid systems, almost all the lipids were present in bilayers with micelles absent and free lipids at very low concentration. These results suggest ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5175802 Thu, 18 Aug 2011 23:00:00 +0100 5175802 http://www.medworm.com/index.php?rid=5175803&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21871874%26dopt%3DAbstract Authors: Tsaloglou MN, Attard GS, Dymond MK Abstract 6-Phosphofructo-1-kinase (PFK-1), a major regulatory enzyme in the glycolysis pathway, is a cytoplasmic enzyme with complicated allosteric kinetics. Here we investigate the effects of lipids on the activity of PFK from Bacillus stearothermophilus (BsPFK), to determine whether BsPFK shares any of the membrane binding or lipid binding properties reported for some mammalian PFKs. Our results show that large unilamellar vesicles (LUVs) composed of either the phospholipid 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or of 1:1 (mole ratio) DOPC and the fatty acid, oleic acid (OA), cause a three-fold increase in V(max), depending on the lipid concentration and vesicle composition, but no change in K(m). Further studies show lipids do... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5175803 Tue, 16 Aug 2011 23:00:00 +0100 5175803 http://www.medworm.com/index.php?rid=5175805&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21864515%26dopt%3DAbstract Authors: Zhou X, Lu Y, Lin X, Yang B, Yang X, Liu Y Abstract Four brominated aliphatic hydrocarbons (1-4), including a novel brominated ene-tetrahydrofuran named as mutafuran H (1), and five sterols (5-9) were isolated from the South China Sea sponge Xestospongia testudinaria. The structure of 1 was determined on the basis of NMR ((1)H, (13)C NMR, HSQC, HMBC, (1)H-(1)H COSY, and NOESY), MS, and optical rotation analysis. Known compounds were identified by comparison of their NMR data with those reported in the literature. Compounds 1-4, and 6-9 were evaluated for their toxicity against Artemia salina larvae, and anti-acetylcholinesterase activity. PMID: 21864515 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5175805 Mon, 15 Aug 2011 23:00:00 +0100 5175805 http://www.medworm.com/index.php?rid=5175804&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21864516%26dopt%3DAbstract Authors: Nishimura H, Setogawa Y, Watanabe T, Honda Y, Watanabe T Abstract Ceriporiopsis subvermispora is a selective white rot basidiomycete which degrades lignin in wood at a distance far from enzymes. Low molecular mass metabolites play a central role in the oxidative degradation of lignin. To understand the unique wood-decaying mechanism, we surveyed the oxidized derivatives of ceriporic acids (alk(en)ylitaconic acids) produced by C. subvermispora using high-resolution liquid chromatography multiple-stage mass spectrometry (HR-LC/MS(n)). The analysis of the precursor and product ions from the extract suggested that an epoxidized derivative of ceriporic acid is produced by the fungus. To identify the new metabolite, an authentic compound of ceriporic acid epoxide was synthesized... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5175804 Thu, 11 Aug 2011 23:00:00 +0100 5175804 http://www.medworm.com/index.php?rid=5157317&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21855534%26dopt%3DAbstract Authors: Raguz M, Mainali L, Widomska J, Subczynski WK Abstract Electron paramagnetic resonance (EPR) spin-labeling methods make it possible not only to discriminate the cholesterol bilayer domain (CBD) but also to obtain information about the organization and dynamics of cholesterol molecules in the CBD. The abilities of spin-label EPR were demonstrated for Chol/POPC (cholesterol/1-palmitoyl-2-oleoylphosphatidylcholine) membranes, with a Chol/POPC mixing ratio that changed from 0 to 3. Using the saturation-recovery (SR) EPR approach with cholesterol analogue spin labels, ASL and CSL, and oxygen or NiEDDA relaxation agents, it was confirmed that the CBD was present in all membrane suspensions when the mixing ratio exceeded the cholesterol solubility threshold (CST). Conventional EP... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5157317 Mon, 08 Aug 2011 23:00:00 +0100 5157317 http://www.medworm.com/index.php?rid=5141344&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21827741%26dopt%3DAbstract In this study, different parameters affecting the achievable accuracy of the MALDI-TOF MS determination of the PC/LPC ratio are compared. It will be shown that particularly the applied laser fluence as well as the used solvents influence the accuracies. Using artificial lipid mixtures it will be demonstrated that the PC/LPC ratio can be determined with an accuracy of about ±10% making the MALDI assay comparable to established methods. Finally, it will be shown that the optimized conditions are also useful to determine the PC/LPC ratios in human seminal plasma. PMID: 21827741 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5141344 Tue, 02 Aug 2011 23:00:00 +0100 5141344 http://www.medworm.com/index.php?rid=5141345&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21827740%26dopt%3DAbstract In this study, we have investigated the antioxidant capacity of melatonin and structural analogues on Fe(2+)-initiated peroxidation of sonicated liposomes made of retinal lipids. The indoleamines were evaluated against butylated hydroxitoluene (BHT) which was chosen as a reference standard because of its high antioxidant capacity. After the addition of Fe(2+) as initiator of lipid peroxidation, quick production of conjugated dienes was observed. With addition of increasing concentrations of BHT the start of the reaction was delayed and initial reaction rates were lower. However, this reduction was not proportional to the increase in concentration. The start of the reaction and initial reaction rates were not modified in the presence of melatonin and its structural analogues. The formation ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5141345 Fri, 29 Jul 2011 23:00:00 +0100 5141345 http://www.medworm.com/index.php?rid=5141343&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21839065%26dopt%3DAbstract Authors: Epand R PMID: 21839065 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5141343 Fri, 29 Jul 2011 23:00:00 +0100 5141343 http://www.medworm.com/index.php?rid=5101763&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21798252%26dopt%3DAbstract Authors: McMurray DN, Bonilla DL, Chapkin RS It is now well established that dietary lipids are incorporated into macrophage and T-cell membrane microdomains, altering their structure and function. Within cell membranes, there are specific detergent-resistant domains in which key signal transduction proteins are localized. These regions are classified as "lipid rafts". Rafts are composed mostly of cholesterol and sphingolipids and therefore do not integrate well into the fluid phospholipid bilayers causing them to form microdomains. Upon cell activation, rafts compartmentalize signal-transducing molecules, thus providing an environment conducive to signal transduction. In this review, we discuss recent novel data describing the effects of n-3 PUFA on alterations in the activation and f... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5101763 Tue, 19 Jul 2011 23:00:00 +0100 5101763 http://www.medworm.com/index.php?rid=5101764&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21784062%26dopt%3DAbstract Authors: Angelini G, Chiarini M, De Maria P, Fontana A, Gasbarri C, Siani G, Velluto D The cationic large unilamellar mixed liposomes from 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) and didodecyldimethylammonium bromide (DDAB) or dioctadecyldimethylammonium bromide (DODAB) were prepared. The influence of the addition of Triton X-100 (TX-100) or octaethylene glycol mono-n-dodecylether (C(12)E(8)) on the membrane integrity was investigated turbidimetrically. The stability of the liposomal systems was estimated by monitoring fluorimetrically at 25°C the rate of spontaneous and surfactant-induced release of entrapped 5(6)-carboxyfluorescein (CF). In order to evaluate the interaction of the cationic DODAB guest with the host POPC membrane, the main phase transition temperatures (T(m))... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5101764 Sun, 17 Jul 2011 23:00:00 +0100 5101764 http://www.medworm.com/index.php?rid=5054244&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21763686%26dopt%3DAbstract Special issue to LipidomicNet and ENOR joint Workshop (19-20 November 2010; Munich, Germany) "Analysis and function of oxysterols and other regulatory and lipotoxic molecular lipid species" Chem Phys Lipids. 2011 Jul 8; Authors: Sharikadze M PMID: 21763686 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5054244 Thu, 07 Jul 2011 23:00:00 +0100 5054244 http://www.medworm.com/index.php?rid=5054248&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21762682%26dopt%3DAbstract Authors: Bach D, Epand RF, Epand RM, Miller IR, Wachtel E An oxidized form of cholesterol, atheronal, is a form found in vivo that has been associated with human pathologies. We have studied mixtures of this oxidized sterol with the phospholipids phosphatidylethanolamine and phosphatidylcholine. We used phospholipids either with palmitoyl and oleoyl acyl chains on the C1 and C2 carbon atoms of glycerol or with both acyl chains being palmitoleoyl. We also compared the effects of atheronal on the curvature properties of these lipids with the action of cholesterol. We studied the bilayer to hexagonal phase transition temperature of mixtures of these lipids using differential scanning calorimetry as well as the dimensions of the hexagonal phase cylinders using X-ray diffraction. Disorderin... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5054248 Tue, 05 Jul 2011 23:00:00 +0100 5054248 http://www.medworm.com/index.php?rid=5054250&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21756886%26dopt%3DAbstract Authors: Souza SL, Hallock KJ, Funari SS, Vaz WL, Hamilton JA, Melo E Cholesteryl esters (CE) are not generally abundant but are ubiquitous in living organisms and have markedly different properties from cholesterol because of their acyl chain. The miscibility/immiscibility of CE with biological lipid structures is a key property for their functions. In this work we study the solubility of cholesteryl oleate (ChO) in a model of the stratum corneum lipid matrix composed of ceramide C16, cholesterol and palmitic acid in excess water. Experiments were done in conditions of fully ionized (pH=9.0) and fully neutralized fatty acid (pH=4.0), and differential scanning calorimetry of the ternary mixtures with added ChO at pH=9.0 clearly displayed a main transition with the same maximum temperat... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5054250 Sat, 02 Jul 2011 23:00:00 +0100 5054250 http://www.medworm.com/index.php?rid=5007569&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21722629%26dopt%3DAbstract We report here the use of matrix-assisted laser desorption and ionization time-of-flight mass spectrometry to monitor changes in the composition and saturation degree of choline phospholipids of hematopoietic progenitor (FDCPmix) cells under standard nutrient-rich culture conditions and at low oxygen and low glucose concentrations. We found that the increase in proliferation rate driven by high concentrations of interleukin-3 (IL-3) is associated with a decrease in membrane phosphatidylcholine (PC) 18:0/20:4 and sphingomyelin (SM) together with an increase in PC 18:0/18:2 and dihydro SM. Furthermore, this effect is most pronounced under low oxygen and low glucose conditions, independent of cell proliferation rates. PMID: 21722629 [PubMed - as supplied by publisher] (Source: Chemistry a... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5007569 Tue, 21 Jun 2011 23:00:00 +0100 5007569 http://www.medworm.com/index.php?rid=5007567&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21723267%26dopt%3DAbstract Authors: Souza SL, Valério J, Funari SS, Melo E Mixtures of ceramides with other lipids in the presence of water are key components of the structure of the lipid matrix of the stratum corneum and are involved in lateral phase separation processes occurring in lipid membranes. Besides their structural role, ceramides are functional for cell signaling and trafficking. We elected, as our object of study, a mixture of N-hexadecanoylceroyl-d-erythro-sphyngosine, C16-Cer, with cholesterol, Ch, in a molar proportion 54:46 in excess water to which palmitic acid, PA, is added in varying amounts. The chosen C16-Cer:Ch proportion replicates the relative abundance of ceramides and cholesterol found in the stratum corneum lipid matrix. For each lipidic composition, we identify the phases in equili... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5007567 Tue, 21 Jun 2011 23:00:00 +0100 5007567 http://www.medworm.com/index.php?rid=5007566&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21723268%26dopt%3DAbstract Authors: Deutch-Kolevzon R, Aserin A, Garti N Water-dilutable microemulsions were prepared and loaded with two types of omega-3 fatty acid esters (omega-3 ethyl esters, OEE; and omega-3 triacylglycerides, OTG), each separately and together with ubiquinone (CoQ(10)). The microemulsions showed high and synergistic loading capabilities. The linear fatty acid ester (OEE) solubilization capacity was greater than that of the bulky and robust OTG. The location of the guest molecules within the microemulsions at any dilution point were determined by electrical conductivity, viscosity, DSC, SAXS, cryo-TEM, SD-NMR, and DLS. We found that OEE molecules pack well within the surfactant tails to form reverse micelles that gradually, upon water dilution, invert into bicontinuous phase and finally int... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5007566 Tue, 21 Jun 2011 23:00:00 +0100 5007566 http://www.medworm.com/index.php?rid=5007568&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21723266%26dopt%3DAbstract Authors: Wallner S, Schmitz G Plasmalogens are a class of phospholipids carrying a vinyl ether bond in sn-1 and an ester bond in sn-2 position of the glycerol backbone. Although they are widespread in all tissues and represent up to 18% of the total phospholipid mass in humans, their physiological function is still poorly understood. The aim of this review is to give an overview over the current knowledge in plasmalogen biology and pathology with an emphasis on neglected aspects of their involvement in neurological and metabolic diseases. Furthermore a better understanding of plasmalogen biology in health and disease could also lead to the development of better diagnostic and prognostic biomarkers for vascular and metabolic diseases such as obesity and diabetes mellitus, inflammation, ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5007568 Mon, 20 Jun 2011 23:00:00 +0100 5007568 http://www.medworm.com/index.php?rid=5007571&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21703251%26dopt%3DAbstract Authors: Guichardant M, Chen P, Liu M, Calzada C, Colas R, Véricel E, Lagarde M Because of their high degree of unsaturation, polyunsaturated fatty acids (PUFA) in mammals, with mainly 18, 20 and 22 carbons, can easily be autooxidized, and converted into many oxidized derivatives and degradation products. This short review reports on some of those relevant to the evaluation of oxidative stress in situ. In addition, the enzyme-dependent oxygenation by both dioxygenases and monooxygenases is briefly reviewed by functional and/or metabolic categories, pointing out the structure variety and the analytical approaches. PMID: 21703251 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5007571 Wed, 15 Jun 2011 23:00:00 +0100 5007571 http://www.medworm.com/index.php?rid=5007570&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21704024%26dopt%3DAbstract This article reviews the known biological functions of PGPLs and the existing mass spectrometric methods. We discuss the different analytical strategies and how ESI-MS/MS can expand our understanding of PGPL homeostasis. PMID: 21704024 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5007570 Wed, 15 Jun 2011 23:00:00 +0100 5007570 http://www.medworm.com/index.php?rid=5007572&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21703250%26dopt%3DAbstract Authors: Iuliano L Cholesterol has many functions, including those that affect biophysical properties of membranes, and is a precursor to hormone synthesis. These actions are governed by enzymatic pathways that modify the sterol nucleus or the isooctyl tail. The addition of oxygen to the cholesterol backbone produces its derivatives known as oxysterols. In addition to having an enzymatic origin, oxysterols can be formed in the absence of enzymatic catalysis in a pathway usually termed "autoxidation," which has been known for almost a century and observed under various experimental conditions. Autoxidation of cholesterol can occur through reactions initiated by free radical species, such as those arising from the superoxide/hydrogen peroxide/hydroxyl radical system and by non-radical hi... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5007572 Tue, 14 Jun 2011 23:00:00 +0100 5007572 http://www.medworm.com/index.php?rid=5007573&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21699886%26dopt%3DAbstract Authors: García-Llatas G, Rodríguez-Estrada MT Over the past 15 years, plant sterol-enriched foods have faced a great increase in the market, due to the asserted cholesterol-lowering effect of plant sterols. However, owing to their chemical structures, plant sterols can oxidize and produce a wide variety of oxidation products with controversial biological effects. Although oxyphytosterols can derive from dietary sources and endogenous formation, their single contribution should be better defined. The following review provides an overall and critical picture on the current knowledge and future perspectives of plant sterols-enriched food, particularly focused on occurrence of plant sterol oxidation products and their biological effects. The final objective of this overview is to evince... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=5007573 Sat, 11 Jun 2011 23:00:00 +0100 5007573 http://www.medworm.com/index.php?rid=4863246&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21570958%26dopt%3DAbstract Authors: Kolter T Sphingolipid and glycosphingolipid levels and expression of sphingolipid metabolizing enzymes are altered in a variety of diseases or in response to drug treatment. Inherited defects of enzymes and other proteins required for the lysosomal degradation of these lipids lead to human sphingolipidoses. Also genetic defects that affect sphingolipid biosynthesis are known. Although the molecular details are often far from clear, (glyco)sphingolipids have been implicated to play a role in atherosclerosis, insulin resistance, cancer, and infections by pathogens. More general aspects of selected diseases are discussed. PMID: 21570958 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4863246 Thu, 05 May 2011 23:00:00 +0100 4863246 http://www.medworm.com/index.php?rid=4863245&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21575612%26dopt%3DAbstract Authors: Chiou YL, Lin SR, Chang LS The goal of the present study is to elucidate the effect of sphingomyelin on interfacial binding of Taiwan cobra phospholipase A(2) (PLA(2)). Substitution of Asn-1 with Met caused a reduction in enzymatic activity and membrane-damaging activity of PLA(2) toward phospholipid vesicles, while sphingomyelin exerted an inhibitory effect on the biological activities of native and mutated PLA(2). Incorporation of sphingomyelin reduced membrane fluidity of phospholipid vesicles as evidenced by Laurdan fluorescence measurement. The results of self-quenching studies, binding of fluorescent probe, trinitrophenylation of Lys residues and fluorescence energy transfer between protein and lipid revealed that sphingomyelin altered differently membrane-bound mode of ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4863245 Thu, 05 May 2011 23:00:00 +0100 4863245 http://www.medworm.com/index.php?rid=4863244&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21575613%26dopt%3DAbstract Authors: Karu K, Turton J, Wang Y, Griffiths WJ Oxysterols are present in mammalian brain at ng/g-μg/g levels while cholesterol is present at the mg/g level. This makes oxysterol analysis of brain challenging. In an effort to meet this challenge we have developed, and validated, an isolation method based on solid phase extraction and an analytical protocol involving oxidation/derivatisation (i.e., charge-tagging) followed by nano-flow liquid chromatography (nano-LC) combined with tandem mass spectrometry utilising multi-stage fragmentation (MS(n)). The oxidation/derivatisation method employed improves detection limits by two orders of magnitude, while nano-LC-MS(n) provides separation of isomers and allows oxysterol quantification. Using this method 13 different oxysterols have been i... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4863244 Thu, 05 May 2011 23:00:00 +0100 4863244 http://www.medworm.com/index.php?rid=4863243&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21575614%26dopt%3DAbstract Authors: Ragot K, Delmas D, Athias A, Nury T, Baarine M, Lizard G In important and severe neurodegenerative pathologies, 7-ketocholesterol, mainly resulting from cholesterol autoxidation, may contribute to dys- or demyelination processes. On various cell types, 7-ketocholesterol has often been shown to induce a complex mode of cell death by apoptosis associated with phospholipidosis. On 158N murine oligodendrocytes treated with 7-ketocholesterol (20μg/mL corresponding to 50μM, 24-48h), the induction of a mode of cell death by apoptosis characterised by the occurrence of cells with condensed and/or fragmented nuclei, caspase activation (including caspase-3) and internucleosomal DNA fragmentation was observed. It was associated with a loss of transmembrane mitochondrial potential (ΔΨ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4863243 Thu, 05 May 2011 23:00:00 +0100 4863243 http://www.medworm.com/index.php?rid=4807828&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21554864%26dopt%3DAbstract Authors: Ogawa S, Mitamura K, Ikegawa S, Krasowski MD, Hagey LR, Hofmann AF, Iida T The (25R)- and (25S)-epimers of C(27) 3α,7α,12α-trihydroxy-5α-cholestan-27-oic acid as well as their corresponding N-acylamidate conjugates with glycine or taurine were prepared starting from cholic acid in 14 steps. The principal reactions involved were (1) reduction of a key intermediary C(24)allo-cholic acid performate with NaBH(4)/triethylamine/ethyl chloroformate, (2) iodination of the resulting 3,7,12-triformyloxy-5α-cholan-24-ol with I(2)/triphenylphosphine; (3) nucleophilic substitution of the iodo derivative with diethylmethyl malonate/NaH; and (4) hydrolysis of the resulting 3,7,12-triformyloxy-25-methyl-26,27-diethyl ester with KOH, followed by decarboxylation of the geminal dicarboxylic... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807828 Wed, 27 Apr 2011 23:00:00 +0100 4807828 http://www.medworm.com/index.php?rid=4807829&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21539818%26dopt%3DAbstract Authors: Kepczynski M, Lewandowska J, Witkowska K, Kędracka-Krok S, Mistrikova V, Bednar J, Wydro P, Nowakowska M This paper reports on the properties of bilayers composed of dioctadecyldimethylammonium bromide (DODAB) and oleic acid (OA) at various molar ratios. The mole fraction of OA, X(OA), was varied in the range of 0-1 and the total lipid content was constant and equal to 10mM. The DODAB/OA dispersions were extruded at a temperature higher than that of the gel-liquid transition of DODAB. The morphology of bilayer structures formed in the dispersions was inspected using a cryogenic transmission electron microscopy (cryo-TEM) and a differential interference contrast microscopy (DIC). The observations revealed that the incorporation of OA into DODAB bilayer results in a decrease of... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807829 Thu, 21 Apr 2011 23:00:00 +0100 4807829 http://www.medworm.com/index.php?rid=4807830&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21531213%26dopt%3DAbstract Authors: Fourgeux C, Bron A, Acar N, Creuzot-Garcher C, Bretillon L Free cholesterol is the predominant form of cholesterol in the neural retina. The vertebrate neural retina exhibits its own capacity to synthesize cholesterol and meets its demand also by taking it from the circulation. Defects in cholesterol synthesis and trafficking in the neural retina has detrimental consequences on its structure and function, highlighting the crucial importance of maintaining cholesterol homeostasis in the retina. Our purpose was to give a review on the functioning of the retina, the role of cholesterol and cholesterol metabolism therein, with special emphasis on cholesterol-24S-hydroxylase (CYP46A1). Similar to the brain, the retina expresses cholesterol-24S-hydroxylase (CYP46A1) and is enriched ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807830 Wed, 20 Apr 2011 23:00:00 +0100 4807830 http://www.medworm.com/index.php?rid=4807833&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21515244%26dopt%3DAbstract In conclusion the analysis of oxysterols in plasma and CSF seems to contribute to investigate the role of cholesterol metabolism in pathogenesis of neurodegeneration and is helpful in the study of patients affected by neurodegenerative diseases. PMID: 21515244 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807833 Fri, 15 Apr 2011 23:00:00 +0100 4807833 http://www.medworm.com/index.php?rid=4807835&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21514284%26dopt%3DAbstract Authors: Vaya J, Szuchman A, Tavori H, Aluf Y Oxysterols are cholesterol (CH)-oxidized products generated in organs via either enzymatic or non-enzymatic pathways. Their presence or absence in cells, tissues and organs may provide information related to, for example, CH level and environmental status, inflammatory conditions near the CH molecules, activity of specific enzymes at and around the CH site, types and concentrations of biochemicals interacting with the CH, and the existence of specific signals. Here we present a mini-review of our lab findings on oxysterols formation in vitro and in vivo, including: the effects of different reactive species and availability of endogenous compounds on the type of oxysterol generated, the effects of enhanced activity of paraoxonase 1 or hemeox... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807835 Thu, 14 Apr 2011 23:00:00 +0100 4807835 http://www.medworm.com/index.php?rid=4807834&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21515243%26dopt%3DAbstract Authors: Postle AD, Henderson NG, Koster G, Clark HW, Hunt AN Stable isotope labelling of lipid precursors coupled with mass spectrometry-based lipidomic analyses and determination of isotope enrichment in substrate, intermediate and product pools provide the parameters needed to determine absolute flux rates through lipid pathways in vivo. Here, as an illustration of the power of such analyses we investigated lung phosphatidylcholine (PC) synthesis in Surfactant Protein-D (SP-D) null mice. These animals develop emphysema, foamy alveolar macrophages and an alveolar lipoproteinosis with increasing age. We used the incorporation of methyl-9-[(2)H] choline chloride coupled with ESI-MS/MS to quantify absolute rates of lung surfactant PC synthesis and secretion in an SP-D(-/-) mouse model, ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807834 Thu, 14 Apr 2011 23:00:00 +0100 4807834 http://www.medworm.com/index.php?rid=4807832&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21524642%26dopt%3DAbstract Authors: Tambaa Y, Terashima H, Yamazaki M The use of giant unilamellar vesicles (GUVs) for investigating the properties of biomembranes is advantageous compared to the use of small-sized vesicles such as large unilamellar vesicles (LUVs). Experimental methods using GUVs, such as the single GUV method, would benefit if there was a methodology for obtaining a large population of similar-sized GUVs composed of oil-free membranes. We here describe a new membrane filtering method for purifying GUVs prepared by the natural swelling method and demonstrate that, following purification of GUVs composed of dioleoylphosphatidylglycerol (DOPG)/dioleoylphosphatidylcholine (DOPC) membranes suspended in a buffer, similar-sized GUVs with diameters of 10-30μm are obtained. Moreover, this method enabl... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807832 Thu, 14 Apr 2011 23:00:00 +0100 4807832 http://www.medworm.com/index.php?rid=4807831&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21524643%26dopt%3DAbstract This article reviews the effects of UVR on cutaneous lipids and examines the contribution of bioactive lipid mediators in the development of sunburn. Since human skin is an active site of polyunsaturated fatty acid (PUFA) metabolism, and these macronutrients can influence the production of eicosanoids/bioactive lipids, as well as modulate cell signalling, gene expression and oxidative stress, the application of PUFA as potential photoprotective agents is also considered. PMID: 21524643 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807831 Thu, 14 Apr 2011 23:00:00 +0100 4807831 http://www.medworm.com/index.php?rid=4807836&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21513705%26dopt%3DAbstract Authors: Mackrill JJ Ionised calcium (Ca(2+)) is a key second messenger, regulating almost every cellular process from cell death to muscle contraction. Cytosolic levels of this ion can be increased via gating of channel proteins located in the plasma membrane, endoplasmic reticulum and other membrane-delimited organelles. Ca(2+) can be removed from cells by extrusion across the plasma membrane, uptake into organelles and buffering by anionic components. Ca(2+) channels and extrusion mechanisms work in concert to generate diverse spatiotemporal patterns of this second messenger, the distinct profiles of which determine different cellular outcomes. Increases in cytoplasmic Ca(2+) concentration are one of the most rapid cellular responses upon exposure to certain oxysterol congeners or t... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807836 Tue, 12 Apr 2011 23:00:00 +0100 4807836 http://www.medworm.com/index.php?rid=4807837&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21501602%26dopt%3DAbstract CONCLUSION: In patients without diabetes mellitus, markers of enhanced cholesterol absorption were a strong predictor for concomitant CVD. PMID: 21501602 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807837 Thu, 07 Apr 2011 23:00:00 +0100 4807837 http://www.medworm.com/index.php?rid=4807839&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21477584%26dopt%3DAbstract Authors: Dhaneshwar S, Tewari K, Joshi S, Godbole D, Ghosh P Prodrug approach using diglyceride as a promoiety is a promising strategy to improve bioavailability of poorly absorbed drugs and the same was explored in the present work to improve oral bioavailability of norfloxacin; a second generation fluoroquinolone antibacterial. The prodrug was synthesized by standard procedures using dipalmitine as a carrier and the structure was confirmed by spectral analysis. Higher LogP indicated improved lipophilicity. The ester linkage between norfloxacin and dipalmitine would be susceptible to hydrolysis by lipases to release the parent drug and carrier in the body. In vivo kinetic studies in rats indicated 53% release of norfloxacin in plasma at the end of 8h. The prodrug exhibited improved ph... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807839 Tue, 05 Apr 2011 23:00:00 +0100 4807839 http://www.medworm.com/index.php?rid=4807838&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21477585%26dopt%3DAbstract Authors: Harvey RD, Barlow DJ, Brain AP, Heenan RK, Zuberi S, Zuberi T, Lawrence MJ Five non-ionic dialkylglycerol poly(oxyethylene) ether surfactants, designated 2C(m)E(n) (where m, the number of carbons in each alkyl chain = 16 or 18, and n, the number of oxyethylene units = 12, 16 or 17) have been examined for their ability to form vesicles when dispersed in water or in an aqueous solution of 154mM NaCl, alone or in the presence of 50 mol% cholesterol. Freeze fracture electron microscopy and light scattering showed that regardless of the hydrating fluid, all the non-ionic surfactants, with the exception of 2C(16)E(17) and 2C(18)E(17), formed vesicles in the absence of cholesterol - 2C(16)E(17) and 2C(18)E(17) instead formed micellar aggregates. All surfactants, however, formed vesic... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807838 Mon, 04 Apr 2011 23:00:00 +0100 4807838 http://www.medworm.com/index.php?rid=4807840&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21440533%26dopt%3DAbstract Authors: Ciepichal E, Jemiola-Rzeminska M, Hertel J, Swiezewska E, Strzalka K The influence of α-cis- and α-trans-polyprenols on the structure and properties of model membranes was analyzed. The interaction of Ficaprenol-12 (α-cis-Prenol-12, α-Z-Prenol-12) and Alloprenol-12 (α-trans-Prenol-12, α-E-Prenol-12) with model membranes was compared using high performance liquid chromatography (HPLC), differential scanning calorimetry (DSC) and fluorescent methods. l-α-Phosphatidylcholine from egg yolk (EYPC) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) as the main lipid components of unilamellar (SUVs) and multilamellar (MLVs) vesicles were used. The two-step extraction procedure (n-pentane and hexane, respectively) allowed to separately analyze the fractions of polyprenol as... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4807840 Thu, 31 Mar 2011 23:00:00 +0100 4807840 http://www.medworm.com/index.php?rid=4643298&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21435339%26dopt%3DAbstract Authors: Gaspar D, Lúcio M, Rocha S, Lima JL, Reis S Phospholipase A(2) (PLA(2)) lipolytic activity can be regarded as a limiting factor for the development of inflammatory processes by restricting the production of pro-inflammatory mediators, hence representing a valuable therapeutic target for drugs that are able to modulate the activity of this enzyme. In the current work, the hydrolysis of phospholipids by PLA(2) was monitored with acrylodan-labelled intestinal fatty acid binding protein (ADIFAB) and this fluorescence based technique was also used to access the enzymatic inhibitory effect of non steroidal anti-inflammatory drugs (NSAIDs). The intrinsic fluorescence of PLA(2) tryptophan residues was further used to gain complementary information regarding the accessibility of these... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4643298 Mon, 21 Mar 2011 00:00:00 +0100 4643298 http://www.medworm.com/index.php?rid=4643300&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21396927%26dopt%3DAbstract Authors: Kużdżał M, Wesołowska O, Strancar J, Michalak K Genistein (5,7,4'-trihydroxyisoflavone) the common soy beans isoflavone has attracted scientific interest due to its antioxidant, estrogenic, antiangiogenic and aniticancer activities. The aim of the present study was to investigate the interaction of genistein with biological (erythrocyte) and model membranes (dimyristoyl- and dipalmitoylphosphatidylcholine). Using Laurdan and Prodan as fluorescent probes, we demonstrated phase behavior and membrane fluidity changes induced by genistein. ESR spectroscopy revealed alterations caused by genistein in membrane domains structure and mobility of spin probes with free radicals located at different depths of membrane. The method of ESR spectra decomposition and computer simulation o... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4643300 Thu, 17 Mar 2011 00:00:00 +0100 4643300 http://www.medworm.com/index.php?rid=4643299&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21419754%26dopt%3DAbstract Authors: Vihervaara T, Jansen M, Uronen RL, Ohsaki Y, Ikonen E, Olkkonen VM Families of oxysterol-binding protein homologues (ORP) are present in eukaryotes from yeast to man. Their hallmark feature is a characteristic ligand binding domain that, for several family members, has been shown to accommodate different oxysterols and/or cholesterol. ORP proteins of the "long" subtype contain targeting determinants for the endoplasmic reticulum and to other organelle membranes, the most prominent of which are phosphoinositide-binding pleckstrin homology domains, while "short" ORPs comprise a ligand binding domain with little additional sequences. There is increasing evidence that both long and short ORPs can be enriched at membrane contact sites, junctions of the endoplasmic reticulum with ot... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4643299 Wed, 16 Mar 2011 00:00:00 +0100 4643299 http://www.medworm.com/index.php?rid=4581984&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21376024%26dopt%3DAbstract Authors: Dietrich U, Krüger P, Käs JA The presence of charged lipids in the cell membrane constitutes the background for the interaction with numerous membrane proteins. As a result, the valence of the lipids plays an important role concerning their lateral organization in the membrane and therefore the very manner of this interaction. This present study examines this aspect, particularly regarding to the interaction of the anionic lipid DPPS with the highly basic charged effector domain of the MARCKS protein, examined in monolayer model systems. Film balance, fluorescence microscopy and X-ray reflection/diffraction measurements were used to study the behavior of DPPS in a mixture with DPPC for its dependance on the presence of MARCKS (151-175). In the mixed monolayer, both lipids ar... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4581984 Wed, 02 Mar 2011 00:00:00 +0100 4581984 http://www.medworm.com/index.php?rid=4581983&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21376712%26dopt%3DAbstract Authors: Cyprych K, Procek J, Langner M, Przybylo M In the paper, we present an improved method for evaluation of a compound ability to destabilize erythrocyte plasma membrane. The proposed method is based on the continuous monitoring of the light scattered by erythrocytes exposed to osmotic pressure differences. The kinetics of hemolysis depends on the plasma membrane mechanics and the extent of the osmotic stress. Generally, the osmotic pressure difference of approximately 150mOsm is taken for measurements, as a result of the equal volume mixing with the physiological salt solutions. In this approach the heamolytic process completion is not established which may result in poor quality and reproducibility of the experimental data. In consequence, inaccurate parameters of the kinetic a... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4581983 Wed, 02 Mar 2011 00:00:00 +0100 4581983 http://www.medworm.com/index.php?rid=4581985&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21354121%26dopt%3DAbstract Authors: Lu G, Gillece TW, Moore DJ Skin is constantly exposed to surfactants which compromise the essential barrier function of normal healthy skin. To model the interactions of surfactants with the barrier lipids of the stratum corneum (SC) it is essential to develop in vitro and in vivo quantitative measurement methods to predict, evaluate, and demonstrate the effect of the different surfactant chemistries and technologies on skin. In the current work, in vitro water vapor uptake and surfactant absorption onto skin lipid model films were quantitatively studied using a technique based on the piezoelectric effect, the quartz crystal microbalance (QCM). This approach is straightforward and reliable in providing subtle surface/interface related mass change information with high resoluti... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4581985 Thu, 24 Feb 2011 00:00:00 +0100 4581985 http://www.medworm.com/index.php?rid=4528036&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21315701%26dopt%3DAbstract Authors: Kaki SS, Adlercreutz P 1-Butanoyl-2-palmitoyl phosphatidylcholine was synthesized from dipalmitoylphosphatidylcholine (DPPC) and butyric acid using a lipase catalyzed transesterification in toluene at controlled water activity. A high fatty acid concentration and low water activity were essential for the enzymatic synthesis. The transesterification resulted in 97.3% incorporation of butyric acid in the sn-1 position with negligible incorporation in the sn-2-position. In mixtures with water, a liquid crystalline phase was formed in equilibrium with a micellar phase. The prepared phospholipid derivative could find applications as a lipidic anticancer prodrug of butyric acid. PMID: 21315701 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4528036 Thu, 17 Feb 2011 00:00:00 +0100 4528036 http://www.medworm.com/index.php?rid=4528035&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21320475%26dopt%3DAbstract Authors: Zhaoy G, Subbaiahz PV, Chiu SW, Jakobsson E, Scotty HL Conjugated linoleic acids (CLA) are found naturally in dairy products. Two isomers of CLA, that differ only in the location of cis and trans double bonds, are found to have distinct and different biological effects. The cis 9 trans 11 (C9T11) isomer is attributed to have the anti-carcinogenic effects, while the trans 10 cis 12 (T10C12) isomer is believed to be responsible for the anti-obesity effects. Since dietary CLA are incorporated into membrane phospholipids, we have used Molecular Dynamics (MD) simulations to investigate the comparative effects of the two isomers on lipid bilayer structure. Specifically, simulations of phosphatidylcholine lipid bilayers in which the sn-2 chains contained one of the two isomers of CLA... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4528035 Sat, 12 Feb 2011 00:00:00 +0100 4528035 http://www.medworm.com/index.php?rid=4473006&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21295560%26dopt%3DAbstract Authors: Gmajner D, Ota A, Sentjurc M, Ulrih NP Temperature and pH effects were studied for stability, structural organization, fluidity and permeability of vesicles from a polar lipid methanol fraction isolated from the Aeropyrum pernix. We determined the permeability of C(25,25) liposomes using fluorescence intensity of released calcein. At pH 7.0 and 9.0, and from 85°C to 98°C, only 10% of entrapped calcein was released. After 10h at 90°C, calcein release reached 27%, independent of pH. Fluorescence anisotropy measurements of hydrophobic probe 1,6-diphenyl-1,3,5-hexatriene revealed gradual changes up to 60°C. At higher temperatures, the anisotropy did not change significantly. Fluorescence alone did not provide detailed and direct structural information about these C(25,25) lipo... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4473006 Thu, 03 Feb 2011 00:00:00 +0100 4473006 http://www.medworm.com/index.php?rid=4473008&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21295021%26dopt%3DAbstract Authors: Chechetkin IR, Osipova EV, Antsygina LL, Gogolev YV, Grechkin AN Lipoxygenases (LOXs) are key enzymes in the biosynthesis of oxylipins, the diverse class of bioregulators involved into developmental processes, signalling and defence. This work was undertaken to better understand how LOXs control production of hydroperoxides with different positional and stereochemistry. A number of glycerolipids were tested as substrates for maize 9-LOX (ZmLOX) and its A562G mutant form. Both the wild type (WT) ZmLOX and A562G mutant were shown to dioxygenate monolinolenoylglycerol (MLG) and 2-linoleoyl-sn-glycero-3-phosphorylcholine (lysoPC). Both the WT ZmLOX and A562G mutant form oxidized the MLG predominantly into (9S)-hydroperoxide. The A562G mutation did not affect the relative yield of ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4473008 Wed, 02 Feb 2011 00:00:00 +0100 4473008 http://www.medworm.com/index.php?rid=4473012&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21291873%26dopt%3DAbstract Authors: Wüstner D, Solanko L, Sokol E, Garvik O, Li Z, Bittman R, Korte T, Herrmann A Cholesterol with BODIPY at carbon-24 of the side chain (BCh2) has recently been introduced as new cholesterol probe with superior fluorescence properties. We compare BCh2 with the intrinsically fluorescent dehydroergosterol (DHE), a well-established marker for cholesterol, by introducing simultaneous imaging of both sterols in model membranes and living cells. BCh2 had a lower affinity than DHE for the biologically relevant liquid-ordered phase in model membranes. Still, DHE and BCh2 trafficked from the plasma membrane to the endocytic recycling compartment (ERC) of BHK cells with identical kinetics. This transport pathway was strongly reduced after energy depletion of cells or expression of the dom... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4473012 Tue, 01 Feb 2011 00:00:00 +0100 4473012 http://www.medworm.com/index.php?rid=4341580&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21215739%26dopt%3DAbstract Authors: Marsh D Data on the location and dimensions of the pivotal surfaces in inverse hexagonal (H(II)) and inverse cubic (Q(II)) phases of phospholipids and glycolipids are reviewed. This includes the H(II) phases of dioleoyl phosphatidylethanolamine, 2:1mol/mol mixtures of saturated fatty acids with the corresponding diacyl phosphatidylcholine, and glucosyl didodecylglycerol, and the Q(II)(230/G) gyroid inverse cubic phases of monooleoylglycerol and glucosyl didodecylglycerol. Data from the inverse cubic phases are largely compatible with those from inverse hexagonal H(II)-phases. The pivotal plane is located in the hydrophobic region, relatively close to the polar-apolar interface. The area per lipid at the pivotal plane is similar in size to lipid cross-sectional areas found in t... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4341580 Wed, 05 Jan 2011 00:00:00 +0100 4341580 http://www.medworm.com/index.php?rid=4341582&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21195067%26dopt%3DAbstract In this report we investigated the interaction of low concentrations of LPS in a buffer with giant unilamellar vesicles (GUVs) of dioleoylphosphatidylcholine (DOPC) membrane in the liquid-crystalline (L(α)) phase and sphingomyelin (SM)/cholesterol(chol) (molar ration; 6/4) membrane in the liquid-ordered (lo) phase. We found that low concentrations (less than critical micelle concentration) of LPS in aqueous solution induced the shape changes such as the transformation from a prolate to a two-spheres-connected by a very narrow neck in the DOPC-GUVs and also in the SM/chol (6/4)-GUVs above their threshold concentrations. The analysis of the shape changes of the GUVs indicates that the monomers of LPS can insert spontaneously into the external monolayer of the lipid membranes of these GUVs f... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4341582 Thu, 30 Dec 2010 00:00:00 +0100 4341582 http://www.medworm.com/index.php?rid=4341581&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21195068%26dopt%3DAbstract Authors: Mansfeld J, Brandt W, Haftendorn R, Schöps R, Ulbrich-Hofmann R The artificial 1,3-diacyl-glycero-2-phosphocholines (1,3-PCs), which form similar aggregate structures as the naturally occurring 1,2-diacyl-sn-glycero-3-phosphocholines (1,2-PCs), were tested as substrates for different classes of phospholipases such as phospholipase A(2) (PLA(2)) from porcine pancreas, bee and snake venom, and Arabidopsis thaliana, phospholipase C (PLC) from Bacillus cereus, and phospholipase D (PLD) from cabbage and Streptomyces species. The regioisomers of the natural phospholipids were shown to bind to all investigated phospholipases with an affinity similar to the corresponding naturally occurring phospholipids, however their hydrolysis was reduced to different degrees (PLA(2)s and PLC) or ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4341581 Thu, 30 Dec 2010 00:00:00 +0100 4341581 http://www.medworm.com/index.php?rid=4341586&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21185813%26dopt%3DAbstract Authors: Mosca M, Ceglie A, Ambrosone L To study the effect of membrane composition on the oxidation of liposomes, different systems were prepared by adding one component at time to phosphatidylcholine (Epikuron 200). In particular, the effect of cholesterol and its ester, cholesterol stearate, on membrane structure and oxidation was studied. A first screening of the structure and net charge of the different preparation was made by means of z-potential and size measurements. Then the liposomes were oxidized by using a hydrophilic radical initiator, the (2,2-azobis(2-amidinopropane) hydrochloride, AAPH, which thermally decomposes to give a constant radical flux in water. The oxidation of liposomes, monitored by following the absorbance of the primary products of oxidation at 234nm, was ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4341586 Fri, 24 Dec 2010 00:00:00 +0100 4341586 http://www.medworm.com/index.php?rid=4341585&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21185814%26dopt%3DAbstract Authors: Wang T, Wang N, Wang T, Sun W, Li T A novel liposome preparation method is described as freeze-drying of water-in-oil emulsions containing sucrose in the aqueous phase (W) and phospholipids and poly(ethylene glycol)(1500) (PEG) in the oil phase (O). The water-in-oil emulsions were prepared by sonication and then lyophilized to obtain dry products. Upon rehydration, the dry products formed liposomes with a size smaller than 200nm and an encapsulation efficiency (EE) higher than 60% for model drugs. The presence of lyoprotectant and PEG was found to be a prerequisite for the formation of liposomes with desirable properties, such as a small particle size and high EE. The lyophilates were stable and could be rehydrated to form liposomes without any change in size or EE even after ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4341585 Fri, 24 Dec 2010 00:00:00 +0100 4341585 http://www.medworm.com/index.php?rid=4341584&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21185815%26dopt%3DAbstract Authors: Ojha B, Das G To evaluate the role of hydrophobic and electrostatic or other polar interactions for protein-ligand binding, we have studied the interactions of bovine serum albumin (BSA) with 2-alkyl malonic acid and 2-alkyl benzimidazole amphiphiles having different head group and alkyl chain length. The binding affinity for the protein-amphiphile interactions is found to depend predominantly on the length of hydrocarbon chain, suggesting the crucial role of hydrophobic forces, supported by polar interactions at the protein surface. The BSA fluorescence exhibits appreciable hypsochromic shift along with a reduction in fluorescence intensity and mean lifetime upon binding with 2-alkyl malonic acid. UV-visible, steady state and time-resolved fluorescence measurements were perfo... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4341584 Fri, 24 Dec 2010 00:00:00 +0100 4341584 http://www.medworm.com/index.php?rid=4341583&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21185816%26dopt%3DAbstract We report here the results of 70ns NAMD molecular dynamics (MD) simulations of LPI and of 2-AGPI in a fully hydrated bilayer of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). These simulations are compared with a 70ns simulation of the cannabinoid CB1 receptor endogenous ligand, N-arachidonoylethanolamine (anandamide, AEA) in a POPC bilayer. These simulations revealed that (1) LPI and 2-AGPI sit much higher in the bilayer than AEA, with inositol headgroups that can at times be solvated completely by water; (2) the behavior of the acyl chains of AEA and 2-AGPI are similar in their flexibilities in the bilayer, while the acyl chain of LPI has reduced flexibility; and (3) both 2-AGPI and LPI can adopt a tilted headgroup orientation by hydrogen bonding to the phospholipid phosphate/g... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4341583 Fri, 24 Dec 2010 00:00:00 +0100 4341583 http://www.medworm.com/index.php?rid=4341588&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21172327%26dopt%3DAbstract Authors: Liu CL, Chang SJ, Chiang HJ The amount of cholesterol (Ch) crystals formed in supersaturated taurochenodeoxycholate (TCDC)-lecithin (L) solutions of the same Ch saturation index (CSI) but at different Ch thermodynamic activities (Ch A(T)) was quantified at different time intervals. The initial Ch nucleation rate (i.e., amount of Ch crystals formed with respect to time) in a Ch A(T)=1.73 and TCDC to L molar ratio (TCDC:L)=5.1 system was faster than that in a Ch A(T)=1.42 and TCDC:L=3.4 system. Shaking could enhance the early appearance of Ch crystals and cause the fast initial Ch nucleation rates for the TCDC:L=5.1 and the TCDC:L=3.4 systems. The final Ch nucleation rates were faster than the initial Ch nucleation rates for the TCDC:L=5.1 and the TCDC:L=3.4 systems. According t... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4341588 Tue, 21 Dec 2010 00:00:00 +0100 4341588 http://www.medworm.com/index.php?rid=4341587&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21172328%26dopt%3DAbstract Authors: Brooks NJ, Ces O, Templer RH, Seddon JM The effect of hydrostatic pressure on lipid structure and dynamics is highly important as a tool in biophysics and bio-technology, and in the biology of deep sea organisms. Despite its importance, high hydrostatic pressure remains significantly less utilised than other thermodynamic variables such as temperature and chemical composition. Here, we give an overview of some of the theoretical aspects which determine lipid behaviour under pressure and the techniques and technology available to study these effects. We also summarise several recent experiments which highlight the information available from these approaches. PMID: 21172328 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4341587 Tue, 21 Dec 2010 00:00:00 +0100 4341587 http://www.medworm.com/index.php?rid=4251608&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21130080%26dopt%3DAbstract Authors: Cook AG, Wardell JL, Imrie CT Seven members of the methyl-6-O-(n-acyl)-α-D-glucopyranosides have been synthesised and their transitional properties determined. The undecanoyl and octadecanoyl members do not exhibit liquid crystallinity while the members having chain lengths between dodecanoyl and hexadecanoyl exhibit a monotropic smectic A phase. Variable temperature infrared spectroscopy reveals that the hydrogen bonding within the system shows a marked change at the melting point but apparently no change at the smectic A-isotropic transition. This observation is interpreted in terms of Goodby's model for the smectic A phase in which the carbohydrate moieties are located at the centre of the smectic bilayer and assuming that hydrogen bonded aggregates persist into the isotro... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4251608 Wed, 01 Dec 2010 00:00:00 +0100 4251608 http://www.medworm.com/index.php?rid=4251611&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21129368%26dopt%3DAbstract Authors: Cadena PG, Araújo AN, Montenegro MC, Pimentel MC, Filho JL, Silva VL The simple and low cost β-cyclodextrin (β-CD) - phenolphthalein (PHP) inclusion complex was used for both the study of physical-chemical parameters and validation of analytical procedures for deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA) determinations in different formulations. The usefulness of this inclusion complex is proposed either in the form of kit reagent and as an original optical sensor for DCA and UDCA. The results showed that temperature had a negative effect on the equilibrium constant resulting in high negative values of enthalpy and positive values of entropy. The half-life values for DCA and UDCA measurements were 68.71 and 294.71 days, respectively. The method was validated showi... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4251611 Tue, 30 Nov 2010 00:00:00 +0100 4251611 http://www.medworm.com/index.php?rid=4251610&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21129369%26dopt%3DAbstract Authors: Carballeira NM, Montano N, Cintrón GA, Márquez C, Rubio CF, Prada CF, Balaña-Fouce R The first total synthesis for the (Z)-16-methyl-11-heptadecenoic acid, a novel fatty acid from the sponge Dragmaxia undata, was accomplished in seven steps and in a 44% 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 10-bromo-1-decanol followed by a second acetylide coupling to the short-chain 1-bromo-4-methylpentane, which resulted in higher yields. Complete spectral data is also presented for the first time for this recently discovered fatty acid and the cis double bo... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4251610 Tue, 30 Nov 2010 00:00:00 +0100 4251610 http://www.medworm.com/index.php?rid=4251609&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21129370%26dopt%3DAbstract Authors: Iida T, Ogawa S, Tamegai H, Adachi Y, Saito H, Ikegawa S, Konishi H, Takagi A, Matsuzaki T The 17-propanamide derivatives of diastereomericΔ(14)-17α- and 17β-estradiols, the potential candidates of a 17β-hydroxysteroid dehydrogenase (17β-HSD) inhibitor, were synthesized in 11 steps from estrone. The principal reactions employed involved in (1) conversion of estrone to the corresponding Δ(14)-estrone, (2) Grignard reaction of Δ(14)-estrone with allylmagnesium bromide followed by regioselective hydroboration of the resulting stereoisomeric 17ξ-allyl-Δ(14)-17ξ-ols with 9-borabicyclo[3.3.1]nonane (9-BBN), and (3)direct amidation of the 17ξ-O-/17ξ-C-spiro-γ-lactones with NH(3) under positive pressure of H(2). PMID: 21129370 [PubMed - as supplied by publisher] (Sour... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4251609 Tue, 30 Nov 2010 00:00:00 +0100 4251609 http://www.medworm.com/index.php?rid=4186610&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21075097%26dopt%3DAbstract Authors: Dejanović B, Noethig-Laslo V, Sentjurc M, Walde P Dilute aqueous systems composed of sodium oleate micelles and sodium oleate/oleic acid vesicles were investigated as a function of pH by electron spin resonance spectroscopy with two lipophilic TEMPO spin labels, TEMPO-stearate, TEMPO-stearamide as well as with a positively charged water soluble spin label, TEMPO-choline. The dynamics of the three TEMPO-spin labels are sensitive to changes in the interfacial region of the aggregates as a function of pH. The results obtained are consistent with the formation of a hydrogen bond network (RCOO(-) ↔ HCOOR) at the surface of the sodium oleate/oleic acid system in the course of the transformation of micelles into the closed bilayers (vesicles). Vesicles formation below pH=10 was de... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4186610 Thu, 11 Nov 2010 00:00:00 +0100 4186610 http://www.medworm.com/index.php?rid=4186611&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21074521%26dopt%3DAbstract CLOSELY RELATED OXIDIZED PHOSPHOLIPIDS DIFFERENTIALLY MODULATE THE PHYSICOCHEMICAL PROPERTIES OF LIPID PARTICLES. Chem Phys Lipids. 2010 Nov 10; Authors: Kar S, Tillu VA, Meena SC, Pande AH Oxidation of glycerophospholipids results in the formation of large variety of oxidized phospholipid products that differs significantly in their chemical compositions and molecular structures. Biological activities of these oxidized products also differ considerably. Here we report the comparisons of the physicochemical properties of non-oxidized phospholipid particle containing two closely related tOx-PLs: 1-palmitoyl-2-(5-keto-6-octendioyl)-sn-glycero-3-phosphocholine (KOdiA-PC) and 1-palmitoyl-2-(9-keto-10-dodecendioyl)-sn-glycero-3-phosphocholine (KDdiA-PC). DMPC (1,2-dimyristoyl-sn-gly... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4186611 Wed, 10 Nov 2010 00:00:00 +0100 4186611 http://www.medworm.com/index.php?rid=4186612&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21073866%26dopt%3DAbstract Authors: López DJ, Collado MI, Ibarguren M, Vasil AI, Vasil ML, Goñi FM, Alonso A The activity of phospholipase C/sphingomyelinase HR(2) (PlcHR(2)) from Pseudomonas aeruginosa was characterized on a variety of substrates. The enzyme was assayed on liposomes (large unilamellar vesicles) composed of PC:SM:Ch:X (1:1:1:1; molar ratio) where X could be PE, PS, PG, or CL. Activity was measured directly as disappearance of substrate after TLC lipid separation. Previous studies had suggested that PlcHR2 was active only on PC or SM. However we found that, of the various phospholipids tested, only PS was not a substrate for PlcHR(2). All others were degraded, in an order of preference PC>SM>CL>PE>PG. PlcHR(2) activity was sensitive to the overall lipid composition of the bilayer, i... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4186612 Tue, 09 Nov 2010 00:00:00 +0100 4186612 http://www.medworm.com/index.php?rid=4154388&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21055393%26dopt%3DAbstract We report here our differential scanning calorimetry measurements investigating the thermotropic phase behaviour of binary dipalmitoylphosphatidylcholine (DPPC)/sterol mixtures containing two saturated sterols with different ring configurations (5β-H and either 3α-OH or 3β-OH). These measurements differ in the proportions of sharp and broad components in the heating endotherms, representing the melting of the sterol-poor and sterol-rich lipid micro-domains of the DPPC bilayer, respectively. Our results suggest that the 5,10-cis ring configuration of both saturated sterols and the ring A conformations have the greatest influence on DPPC bilayer properties, most likely by inducing small increases in the mean area/molecule as compared to cholesterol. However, the C3-OH orientation also inf... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4154388 Tue, 02 Nov 2010 00:00:00 +0100 4154388 http://www.medworm.com/index.php?rid=4154387&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21055394%26dopt%3DAbstract Authors: Matthew GK, David AM, Ronald NM It is commonly believed that all membrane sterols are rigid all-trans ring systems with a fully extended alkyl side-chain and similarly influence phospholipid bilayer physical properties. Here, we report the sterol concentration-dependent, thermotropic phase behaviour of binary dipalmitoylphosphatidylcholine (DPPC)/sterol mixtures containing two similar 5α-H sterols with different functional group orientations (3α-OH or 3β-OH), which adopt an ideal all-trans planar ring conformation but lack the deformed ring B conformation of cholesterol (Chol) and epicholesterol (Echol), using differential scanning calorimetry (DSC). Our deconvolution of the DSC main phase transition endotherms show differences in the proportions of sterol-poor (sharp) and ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4154387 Tue, 02 Nov 2010 00:00:00 +0100 4154387 http://www.medworm.com/index.php?rid=4154386&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21055395%26dopt%3DAbstract In this study affinity chromatography on MPO-Sepharose showed that MPO-LDL complexes are uncoupled at ionic strength above 0.3M NaCl or when pH of solution goes below 3.6. This is an evidence of ionic interaction between MPO and LDL. We used spin probes of lipid nature embedded in phospholipid monolayer so that a variety of distances between the surface of an LDL particle and the paramagnetic center of a spin probes was provided. Since MPO interaction with labeled LDL caused no alteration of EPR spectra it was concluded that lipid components of LDL are not involved in MPO binding. Analysis of Mn(2+) distribution between LDL surface and the aqueous milieu showed that the surface negative charge of LDL is not considerably changed upon interaction with MPO. It can be suggested that interactio... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4154386 Tue, 02 Nov 2010 00:00:00 +0100 4154386 http://www.medworm.com/index.php?rid=4088605&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20951686%26dopt%3DAbstract Authors: Pinchuk I, Shoval H, Bor A, Schnitzer E, Dotan Y, Lichtenberg D Evaluation of the activity of antioxidants is commonly based on measurements of the effect of a specific antioxidant on redox reactions conducted in a solution. Given the difference between reactions that occur in homogeneous solutions and those that occur at lipid-water interfaces, as in biological membranes and lipoproteins, the relevance of the commonly-used assays (such as TEAC and ORAC) to the antioxidative activity in biological systems is questionable. The aim of the present investigation is to develop a more relevant assay. Based on our results, we propose an assay based on prolongation of the lag preceding fast peroxidation of serum lipids. The assay employs our previously developed procedure for determin... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4088605 Wed, 13 Oct 2010 23:00:00 +0100 4088605 http://www.medworm.com/index.php?rid=4088604&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20951687%26dopt%3DAbstract Authors: Das P, De J The crystal structure as well as the microstructure, i.e., size and strain, of crystallites of cholesteryl oleyl carbonate was determined from X-ray powder diffraction data. The X-ray line broadening was analyzed through the refinement of TCH-pseudo-Voigt function parameters (isotropic effects) and the refinement of multipolar functions, i.e., symmetrized cubic harmonics (anisotropic effects). The crystal structure turns out to be primitive monoclinic, space group Pc, type I monolayer having two molecules per unit cell with parameters: a=18.921±0.006Ǻ, b=12.952±0.003Ǻ, c=9.276±0.002Ǻ and β=91.32±0.03°. The average size of a well ground specimen of crystallites was 60nm. The average micro-strain, e.g., 45×10(-4) has been tentatively attributed to fatty cha... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4088604 Wed, 13 Oct 2010 23:00:00 +0100 4088604 http://www.medworm.com/index.php?rid=4064037&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20932961%26dopt%3DAbstract This study examines the protective effect of arzanol, a pyrone-phloroglucinol etherodimer from Helichrysum italicum subsp. microphyllum, against the oxidative modification of lipid components induced by Cu(2+) ions in human low density lipoprotein (LDL) and by tert-butyl hydroperoxide (TBH) in cell membranes. LDL pre-treatment with arzanol significantly preserved lipoproteins from oxidative damage at 2h of oxidation, and showed a remarkable protective effect on the reduction of polyunsaturated fatty acids and cholesterol levels, inhibiting the increase of oxidative products (conjugated dienes fatty acids hydroperoxides, 7β-hydroxycholesterol, and 7-ketocholesterol). Arzanol, at non cytotoxic concentrations, exerted a noteworthy protection on TBH-induced oxidative damage in a line of fibro... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4064037 Mon, 04 Oct 2010 23:00:00 +0100 4064037 http://www.medworm.com/index.php?rid=4064036&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20932962%26dopt%3DAbstract Authors: Wu J, Teuber K, Eibisch M, Fuchs B, Schiller J Lipid (phospholipid) oxidation is an increasingly important research topic due to the significant physiological relevance. The Fenton reaction, i.e. the transition metal catalyzed decomposition of H(2)O(2) is frequently used to generate hydroxyl radicals (HO(•)). Lipids with unsaturated fatty acyl residues, are primarily converted by HO(•) radicals into peroxides. In contrast, chloro- and bromohydrins as well as dihalogenides are formed by the addition of HOCl or HOBr to the olefinic groups of the fatty acyl residues of lipids or under the influence of the enzyme myeloperoxidase (MPO) from Cl(-) and H(2)O(2). We will show here by using MALDI-TOF MS for product analysis that halogenated products may also be generated in the pre... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4064036 Mon, 04 Oct 2010 23:00:00 +0100 4064036 http://www.medworm.com/index.php?rid=4064035&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20932963%26dopt%3DAbstract Authors: Sánchez M, Aranda FJ, Teruel JA, Ortiz A Phosphatidylethanolamine-based pH-sensitive liposomes of various compositions have been described as efficient systems for cytoplasmic delivery of molecules into cells. Incorporation of an amphiphile of appropriate structure is needed for the stabilization and performance of these vesicles. Among the wide variety of interesting activities displayed by Pseudomonas aeruginosa dirhamnolipids (diRL), is their capacity to stabilize bilayer structures in phosphatidylethanolamine systems. In this work, X-ray scattering, dynamic light scattering, fluorescence spectroscopy and fluorescence microscopy have been used to study the structure and pH-dependent behaviour of phosphatidylethanolamine/diRL liposomes. We show that diRL, in combination wit... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4064035 Mon, 04 Oct 2010 23:00:00 +0100 4064035 http://www.medworm.com/index.php?rid=4064034&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20932964%26dopt%3DAbstract Authors: Yarrow F, Kuipers BW Temperature-controlled Atomic Force Microscopy (TC-AFM) in Contact Mode is used here to directly image the mechanisms by which melting and crystallization of supported, hydrated DPPC bilayers proceed in the presence and absence of the model peptide WALP23. Melting from the gel L(β)' to the liquid-crystalline L(α) phase starts at pre-existing line-type packing defects (grain boundaries) in absence of the peptide. The exact transition temperature is shown to be influenced by the magnitude of the force exerted by the AFM probe on the bilayer, but is higher than the main transition temperature of non-supported DPPC vesicles in all cases due to bilayer-substrate interactions. Cooling of the fluid L(α) bilayer shows the formation of the line-type defects at t... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4064034 Mon, 04 Oct 2010 23:00:00 +0100 4064034 http://www.medworm.com/index.php?rid=4045405&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20875402%26dopt%3DAbstract Authors: Mervyn B, Yolandy L, Madrey D, R AD, S BM, Gani K, M IM, R RR, Cornelia T, Johan G, Gianna T, V RV, Lynne P, Sandra VW, Nsovo M, Mohammed B, C SA, A VJ Cell wall mycolic acids (MA) from Mycobacterium tuberculosis (M.tb) are CD1b presented antigens that can be used to detect antibodies as surrogate markers of active TB, even in HIV coinfected patients. The use of the complex mixtures of natural MA is complicated by an apparent antibody cross-reactivity with cholesterol. Here firstly we report three recombinant monoclonal scFv antibody fragments in the chicken germ-line antibody repertoire, which demonstrate the possibilities for cross-reactivity: the first recognized both cholesterol and mycolic acids, the second mycolic acids but not cholesterol, and the third cholesterol but ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4045405 Thu, 23 Sep 2010 23:00:00 +0100 4045405 http://www.medworm.com/index.php?rid=4006080&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20869958%26dopt%3DAbstract Authors: Jacquemet A, Vié V, Lemiègre L, Barbeau J, Benvegnu T The synthesis of novel archaeal lipid analogues is described. The hydrophobic core of these tetraether bipolar lipids were based on a disubstituted 1,3-cyclopentane unit which was further equipped with mannosyl polar head groups. This hemimacrocylcic tetraether structure that can be compared to rare archaeal lipids permit to establish the behavior of such bipolar lipid at the air/water interface. The two oxygen atoms and the cyclopentane ring were found to be of importance on this behavior. Indeed, the air/water interface comparative study of tetraether- and diether-type lipids led to conclusions on a bent conformation of the tetraether at the air/water interface in the presence of a cyclopentane unit even if the pres... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4006080 Wed, 22 Sep 2010 23:00:00 +0100 4006080 http://www.medworm.com/index.php?rid=4006081&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20863821%26dopt%3DAbstract Authors: Allen K, Francisco H, Layton B Quantification of the mechanical properties of liposomes is critical in helping to predict their behavior during various applications such targeted drug delivery, response to mechanical characterization or their interactions with isolated cytoskeletal elements. A numerical implementation of the Evans aspiration technique, and an image-processing algorithm for measuring deformation of spherical DOPC:DOPS liposomes is presented. Liposomes were aspirated to pressures of -10 mmHg (∼ -1300Pa). The area expansion and Young's moduli of the liposomes were found to be 0.067 N·m(-1) (67±4 dynes/cm) and 15±1 MPa. PMID: 20863821 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=4006081 Sun, 19 Sep 2010 23:00:00 +0100 4006081 http://www.medworm.com/index.php?rid=3988203&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20849838%26dopt%3DAbstract Authors: Trikash I, Gumenyuk V, Lishko V The various experimental approaches and octadecyl rhodamine B chloride (R18) assay's capability to meet the criteria for examining the Ca(2+)dependent synaptic vesicles (SVs) fusion with target membranes have been investigated. The existence of at least two simultaneous processes one of which attributed to real Ca(2+)-dependent membrane fusion, while another is considered to be non-specific probe transfer has been shown. The differences in response to temperature changes were found for R18 fluorescence dequenching upon stimulation of membrane fusion or nonspecific probe transfer. The temperature dependences of the probe dequenching rate were the same for heterotypic and homotypic membrane systems and increased with the temperature growth. The co... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3988203 Mon, 13 Sep 2010 23:00:00 +0100 3988203 http://www.medworm.com/index.php?rid=3973698&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20836998%26dopt%3DAbstract Authors: Byun HS, Bittman R Deuteration at C-4 and C-5 of sphingosine was achieved via a hydrogen-deuterium exchange reaction of a β-ketophosphonate intermediate catalyzed by ND(4)Cl in D(2)O/tetrahydrofuran. To install deuterium at C-3 of sphingosine and sphingomyelin, sodium borodeuteride reduction/cerium(III) chloride reduction of an α,β-enone in perdeuteromethanol was used. PMID: 20836998 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3973698 Thu, 09 Sep 2010 23:00:00 +0100 3973698 http://www.medworm.com/index.php?rid=3973699&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20833161%26dopt%3DAbstract Authors: Villasuso AL, Wilke N, Maggio B, Machado E Diacylglycerol pyrophosphate (DGPP), a phosphorylated form of phosphatidic acid (PA), gained attention recently due to its role as signaling lipid. However, little is known about its surface organization and potential impact on membrane-mediated function. In this work we investigated the interfacial behavior of Langmuir monolayers formed with pure DGPP and of its mixtures with PA. We found that changes of the subphase pH affect the surface behavior of DGPP. At pH 8, DGPP forms liquid expanded monolayers with a compressibility modulus of about 60 mN m(-1) at collapse. On acidic solutions, the compressibility modulus increases to 90 mN m(-1) and the average molecular area is smaller. At pH 8, DGPP and its precursor PA form thermodynamic... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3973699 Wed, 08 Sep 2010 23:00:00 +0100 3973699 http://www.medworm.com/index.php?rid=3900456&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20728436%26dopt%3DAbstract Authors: Gallová J, Uhríková D, Kučerka N, Teixeira J, Balgavý P The influence of cholesterol on the structural parameters of phosphatidylcholine bilayers is studied by small angle neutron scattering on unilamellar liposomes. Monounsaturated diacylphosphatidylcholines diCn:1PC with the length of acyl chains n=14, 18 and 22 are used. We confirme that the bilayer thickness increases with increasing concentration of cholesterol for all studied diCn:1PC. However, partial areas per diCn:1PC and cholesterol molecule on lipid - water interface are found not to dependend of cholesterol concentration. The partial area per cholesterol molecule is 0.24 nm(2). In addition, the partial area per diC18:1PC is larger than that for diC14:1PC and diC22:1PC. PMID: 20728436 [PubMed - as... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3900456 Wed, 18 Aug 2010 23:00:00 +0100 3900456 http://www.medworm.com/index.php?rid=3900457&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20727866%26dopt%3DAbstract Authors: Kearns MD, Patel YN, Savva M The physicochemical properties of a novel series of cholesterol-based cationic lipids in the presence of DOPE were studied by various techniques in an effort to correlate cationic lipid structure with transfection efficacy. It was found that while DOPE improves the beta-gal activity of the active AC and MC derivatives, the overall zeta potential of the particles, pDNA complexation and condensation is not improved. This is in stark contrast with the tertiary amine derivative DC whose dispersion properties were improved and its monolayer surface potential is restored at high molecular surface density in the presence of DOPE. Overall the transfection activity mediated by DC and the quaternary ammonium TC derivative was greatly improved in the presence... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3900457 Tue, 17 Aug 2010 23:00:00 +0100 3900457 http://www.medworm.com/index.php?rid=3855553&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20691168%26dopt%3DAbstract Authors: Brittes J, Lúcio M, Nunes C, Lima JL, Reis S The current study gathers a range of spectrophotometric and spectrofluorimetric techniques to systematically monitor the effects of resveratrol (trans-3,5,4'-trihydrostilbene) on the biophysical properties of membrane model systems consisting of unilamellar liposomes of phosphatidylcholine (DPPC) with the ultimate goal of relating these effects with some of the well documented pharmacological properties of this compound, and clarifying some controversial results reported on the literature. Physiological conditions have been pursued, such as a buffered pH control with adjusted ionic strength similar to the blood plasma conditions (pH 7.4, I=0.1M) and the study at different membrane physical states (gel phase and fluid phase) for t... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3855553 Wed, 04 Aug 2010 23:00:00 +0100 3855553 http://www.medworm.com/index.php?rid=3795428&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20654600%26dopt%3DAbstract Authors: Hąc-Wydro K The activity of phytosterols on human organism includes the ability of these compounds to incorporate into membranes. In the consequence the plant sterols are able to increase of total sterol concentration in membrane or/and to replace cholesterol molecules. The aim of this work was to compare the influence of both these effects on the properties of model erythrocyte membranes. Moreover, the interactions between the plant sterols (beta-sitosterol and stigmasterol) and saturated-monounsaturated phosphatidylcholine were investigated and the condensing and ordering potency of these phytocompounds on membrane phospholipids were thoroughly analyzed. It was found that the addition of the plant sterols into model membrane modifies the condensation, ordering and interac... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3795428 Mon, 19 Jul 2010 23:00:00 +0100 3795428 http://www.medworm.com/index.php?rid=3795427&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20654601%26dopt%3DAbstract Authors: Omonov TS, Bouzidi L, Narine SS A robust, well defined and reproducible method to accurately measure the oil binding capacity (OBC) of structuring fats was developed. The method was validated using two oil/fat model systems, i.e. fully hydrogenated canola oil (FHCO) in canola oil (CO) (FHCO/CO) and fully hydrogenated soybean oil (FHSO) in CO (FHSO/CO). The mixtures were crystallized from the melt down to three different temperatures (15, 25 and 35 degrees C) at constant rates of cooling and the OBC was measured after different periods of storage time. The critical concentration of hard fat at which the solid fat network is stable and effectively binds oil has been also measured for mixtures crystallized at temperature close to room temperatures, i.e., 25 degrees C. Crystal str... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3795427 Mon, 19 Jul 2010 23:00:00 +0100 3795427 http://www.medworm.com/index.php?rid=3795426&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20654602%26dopt%3DAbstract Authors: Berdeaux O, Gregoire S, Fournier C, Christie WW, Lambelet P, Sébédio JL The purpose of this work was to identify an unknown component which has been detected during the analysis of cyclic fatty acid monomers (CFAMs) in low erucic acid rapeseed oils (LEAR). A sample of crude LEAR was transformed into fatty acid methyl esters (FAMEs) and hydrogenated using PtO(2). The hydrogenated sample was fractionated by reversed-phase high-performance liquid chromatography (RP-HPLC) and the fraction containing the CFAMs transformed into picolinyl esters. Analysing these picolinyl derivatives by gas-liquid chromatography coupled to mass spectrometry (GC-MS) showed that the unknown product observed in LEAR is the 11,12-methylene-octadecanoic acid. This cyclic fatty acid was also found in... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3795426 Mon, 19 Jul 2010 23:00:00 +0100 3795426 http://www.medworm.com/index.php?rid=3734305&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20599851%26dopt%3DAbstract Authors: Kinoshita M, Ito K, Kato S We analyzed the kinetics for the subgel (SGI) phase formation in DPPC/DOPC binary bilayers, paying attention to DOPC-induced modification of the bilayer physical properties. Differential, scanning calorimetry and X-ray diffraction revealed that addition of DOPC reduced the apparent initial, lag time to start the SGI phase formation, and that the SGI phase in the binary bilayers had basically the, same structure as that in pure DPPC bilayers though addition of DOPC markedly increased the peak, temperature and enthalpy of the subtransition in heating. Moreover, addition of DOPC abolished the, prolongation of the initial lag time in pure DPPC bilayers induced by lowering the incubation, temperature from 0 degrees C to -5 degrees C. Our results suggested... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3734305 Thu, 01 Jul 2010 23:00:00 +0100 3734305 http://www.medworm.com/index.php?rid=3734304&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20599852%26dopt%3DAbstract Authors: Tsuzuki W We investigated the heat-induced cis/trans isomerization of double bonds in monounsaturated lipids. When triolein (9-cis, 18:1) was heated around 180 degrees C, small amounts of isomerization products were obtained depending on the heating period. The heat-induced isomerization of triolein was considerably suppressed by the addition of different antioxidants or under nitrogen stream, and these additives simultaneously inhibited the thermal oxidation of double bonds in triolein. Therefore, an intermediate of the thermal oxidation reaction might be responsible for the heat-induced isomerization of the double bonds in triolein. The thermodynamics of the heat-induced isomerization of triolein (9-cis, 18:1) and trielaidin (9-trans, 18:1) were investigated using Arrhenius ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3734304 Thu, 01 Jul 2010 23:00:00 +0100 3734304 http://www.medworm.com/index.php?rid=3734306&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20599539%26dopt%3DAbstract Authors: Marsh D Data on the molecular volumes of phospholipids and glycolipids in membranes are collected together in order to determine the contributions from the component groups, for as wide a range of lipids as possible, including sphingolipids. Wherever possible, the volumes of the methylene groups in the lipid chains are established from the dependence on chain length at fixed temperature in a given phase. In this way, it is also possible to determine the constant contribution from cis double bonds in the chains of monoenoic unsaturated phosphatidylcholines, and the volume of the branched methyl groups in isoacyl phosphatidylcholines. Issues concerning separation of contributions from the polar head groups from those of the chain terminal methyl groups are discussed. Molecular v... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3734306 Thu, 24 Jun 2010 23:00:00 +0100 3734306 http://www.medworm.com/index.php?rid=3734303&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20599853%26dopt%3DAbstract In this study we compile densities of methyl and ethyl esters published in literature, and proposed equations to convert them to 15 degrees C and to predict the biodiesel density based on its chain length and unsaturation degree. Both expressions were validated for a wide range of commercial biodiesel fuels. Using the latter, we define a term called Biodiesel Cetane Index, which predicts with high accuracy the biodiesel cetane number. Finally, simple calculations prove that the introduction of high-biodiesel content blends in the fuel market would force the refineries to reduce the density of their fossil fuels. PMID: 20599853 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3734303 Thu, 24 Jun 2010 23:00:00 +0100 3734303 http://www.medworm.com/index.php?rid=3734302&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20599854%26dopt%3DAbstract In this study, transesterification/acetylation of long chain fatty alcohols is simply carried out by dissolving the alcohol in ethyl/methyl acetate and passing through a micro-column packed with solid NaOH. Reaction times are slightly different for alcohols of different chain length. Rice bran alcohols of 24 - 34 carbon atom are successfully acetylated. Also, castor oil methyl ester can be interesterified but with longer reaction time. PMID: 20599854 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3734302 Tue, 22 Jun 2010 23:00:00 +0100 3734302 http://www.medworm.com/index.php?rid=3734301&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20599855%26dopt%3DAbstract Authors: Frederick TE, Goff PC, Mair CE, Farver RS, Long JR, Fanucci GE Bis(monoacylglycero)phosphate (BMP) is an endosomal lipid with a unique structure that is implicated in the formation of intraendosomal vesicular bodies. Here we have characterized the effects of dioleoyl BMP (BMP(18:1)) at concentrations of 5, 10, 15 and 20 mol% on the thermotropic behavior of dipalmitoyl phosphatidylcholine (DPPC) vesicles, and compared them to those of equimolar concentrations of dioleoyl phosphatidylglycerol (DOPG), a structural isoform of BMP(18:1). Because BMP is found in the acidic environments of the late endosome and intralysosomal vesicles, samples were prepared at pH 4.2 to mimic the pH of the lysosome. Both (2)H NMR of perdeuterated DPPC and spin-labeled EPR with 16-Doxyl phosphatidylch... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3734301 Fri, 18 Jun 2010 23:00:00 +0100 3734301 http://www.medworm.com/index.php?rid=3734300&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20599856%26dopt%3DAbstract Authors: Teixeira AC, Garcia AR, Ilharco LM, Silva AM, Fernandes AC The phase behaviour of pure oleanolic acid (OLA) and in mixtures with stearic acid (SA) was characterized by differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and nuclear magnetic resonance (NMR). The crystalline OLA as received (OLA(ar)) becomes amorphous after being dissolved in chloroform and vacuum-dried at 50 degrees C (OLA(50)). Upon heating, both forms transform to the needle shape crystalline form (OLA(220)). Dimerization through H-bonding between COOH groups was detected both in OLA(ar) and OLA(220). Dimers are stronger in OLA(220), where H-bonding involves the alcohol groups and also plays a role in the crystalline org... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3734300 Fri, 18 Jun 2010 23:00:00 +0100 3734300 http://www.medworm.com/index.php?rid=3702099&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20573597%26dopt%3DAbstract Authors: Muzael M, Koza G, Dulayymi JJ, Baird MS The synthesis of (2R,3R,Z)-2-docosyl-3-hydroxytetracont-21-enoic acid, a significant alpha'-mycolic acid of Mycobacterium smegmatis and other mycobacteria is reported. PMID: 20573597 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3702099 Thu, 03 Jun 2010 23:00:00 +0100 3702099 http://www.medworm.com/index.php?rid=3691927&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20561982%26dopt%3DAbstract Authors: Zant-Przeworska E, Stasiuk M, Gubernator J, Kozubek A Alkylresorcinolic lipids isolated from cereal grains and their semi-synthetic myristoyl-sulphonyl derivatives (MSAR) were used to modify small long-circulating sphingomyelin-cholesterol liposomes. Those SM:Chol vesicles modified with 10-30mol% resorcinolic lipids had stable size and low membrane permeability in vitro at 4 degrees C and 37 degrees C. Liposomes containing 30mol% MSAR showed very fast solute release in the presence of human plasma at 37 degrees C, which was drastically diminished in heat-inactivated plasma. In vivo studies showed that unmodified SM:Chol liposomes and those modified with alkylresorcinols were eliminated from the circulation more slowly than liposomes with the highest concentration of MSAR in me... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3691927 Mon, 31 May 2010 23:00:00 +0100 3691927 http://www.medworm.com/index.php?rid=3626502&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20513376%26dopt%3DAbstract Authors: Robaszkiewicz A, Greig FH, Pitt AR, Spickett CM, Bartosz G, Soszyński M Hypochlorite generated in vivo under pathological conditions is a known oxidant and chlorinating agent, able to react with proteins and lipids, which affects the stability of biological membranes. Reaction with unsaturated fatty acyl chains in glycerophospholipids such as phosphatidylcholine results in the formation of chlorohydrins. The aim of this study was to determine the effects of chlorohydrins formed by the reaction of hypochlorite with 1-stearoyl-2-oleoyl-, 1-stearoyl-2-linoleoyl-, and 1-stearoyl-2-arachidonylphosphatidylcholine on biophysical properties of bilayers and their effects on human erythrocytes. Using electrospray mass spectrometry we observed complete conversion of the lipids into ch... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3626502 Wed, 26 May 2010 23:00:00 +0100 3626502 http://www.medworm.com/index.php?rid=3582336&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20471966%26dopt%3DAbstract Authors: Mintzer E, Charles G, Gordon S Oxidized analogs of cholesterol (oxysterols) are produced through both enzymatic and non-enzymatic pathways and have been shown to perturb membrane properties in vitro and in vivo. In the present study, the membrane behavior of two naturally occurring oxysterols, 25-hydroxycholesterol and 7-ketocholesterol, was examined in two model systems. The presence of an additional oxygen moiety was found to alter membrane properties compared to native cholesterol and to each other in lipid monolayers, composed of either pure sterol or sterol-glycerophospholipid and sterol-sphingomyelin binary films, as well as in mixed multilamellar vesicles. The ability of oxysterols to condense phosphatidylcholine and sphingomyelin films, their capacity to cause changes ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3582336 Wed, 12 May 2010 23:00:00 +0100 3582336 http://www.medworm.com/index.php?rid=3582337&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20470766%26dopt%3DAbstract Authors: Bouzidi L, Boodhoo MV, Kutek T, Filip V, Narine SS The binary phase behavior of purified 1, 3 -dilauroyl-2-stearoyl-sn-glycerol (LSL) and 1, 2 -dilauroyl-3-stearoyl-sn-glycerol (LLS) was investigated at a slow (0.1 degrees C/min) and a relatively fast (3.0 degrees C/min) cooling rate in terms of melting and crystallization, polymorphism, solid fat content (SFC), hardness and microstructure. Much of the behavior of the system is explained by its polymorphism and the influence of thermal processing. The alpha- form and the beta'- form of a double chain length structure were detected in the mixtures cooled at 3.0 degrees C/min, whereas only the beta'- form was detected in those cooled at 0.1 degrees C/min. X-ray diffraction data as well as thermodynamic data propose that the most... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3582337 Mon, 10 May 2010 23:00:00 +0100 3582337 http://www.medworm.com/index.php?rid=3570395&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20465994%26dopt%3DAbstract Authors: Villeneuve M, Kawai M, Watanabe M, Aoyagi Y, Hitotsuyanagi Y, Takeya K, Gouda H, Hirono S, Minnikin DE, Nakahara H Phase diagrams of Langmuir monolayers of alpha-mycolic acids (alpha-MAs) from representative slow growing mycobacteria were intensively analyzed over a range of temperatures, by using so-called type-1 alpha-MAs having two ciscyclopropyl groups from Mycobacterium tuberculosis, Mycobacterium kansasii and Mycobacterium avium-intracellulare complex (MAC) and type-3 alpha-MA, having one cis-cyclopropyl and one cis-double bond from Mycobacterium bovis BCG and MAC. Their intrachain groups are either cis-cyclopropyl or cisdouble bond but the methylene chain segment lengths vary greatly. However, their monolayer features were alike: At lower temperatures and surface pressu... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3570395 Sun, 09 May 2010 23:00:00 +0100 3570395 http://www.medworm.com/index.php?rid=3546019&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20447383%26dopt%3DAbstract Authors: Tristram-Nagle S, Kim DJ, Akhunzada N, Kučerka N, Mathai JC, Katsaras J, Zeidel M, Nagle JF Diphytanoylphosphatidylcholine (DPhyPC) is a branched chain lipid often used for model membrane studies, including peptide/lipid interactions, ion channels and lipid rafts. This work reports results of volume measurements, water permeability measurements P(f), X-ray scattering from oriented samples, and x-ray and neutron scattering from unilamellar vesicles at T=30 (o)C. We measured the volume/lipid V(L)=1426+/-1A(3). The area/lipid was found to be 80.5+/-1.5A(2) when both x-ray and neutron data were combined with the SDP model analysis (Kucerka et al., 2008); this is substantially larger than the area of DOPC which has the largest area of the common linear chain lipids. P(f) was mea... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3546019 Sun, 02 May 2010 23:00:00 +0100 3546019 http://www.medworm.com/index.php?rid=3531059&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20435025%26dopt%3DAbstract Authors: Di Gregorio GM, Ferraris P, Mariani P The combined effect of trehalose and temperature on the wetting properties of L-alpha-dioleoyl-phosphatidyl-choline (DOPC) model membranes in excess aqueous solutions has been analyzed by X-ray di_raction and extended electron density map reconstruction. At room temperature, DOPC in excess water forms a fluid lamellar L(alpha) phase. In the presence of trehalose, no phase transitions occur, but repeat and intermembrane distances increase considerably. Electron density maps show that trehalose in solution promotes a straightening of the hydrocarbon chain packing and a reduction of the molecular average area at the polar-apolar interface. Accordingly, the increased intermembrane distance is interpreted as a clear indication of a sugar screen... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3531059 Wed, 28 Apr 2010 23:00:00 +0100 3531059 http://www.medworm.com/index.php?rid=3531061&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20433819%26dopt%3DAbstract Authors: Nguyen TH, Rao NZ, Schroeder WM, Moore PB The conformations of model transmembrane peptides are studied to understand the structural and dynamical aspects of tetrameric bundles using a series of coarse grain (CG) molecular dynamics (MD) simulations since membrane proteins play a crucial role in cell function. In this work, two different amphipathic models have been constructed using similar hydrophobic/hydrophilic characteristics with two structurally distinct morphologies to evaluate the effect of roughness and hydrophilic topology on the structure of tetrameric bundles, one class that forms an ion-channel and one class that does not. Free energy calculations of typical amphipathic peptide topologies show that using a relatively smooth surface morphology allows for a stable c... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3531061 Mon, 26 Apr 2010 23:00:00 +0100 3531061 http://www.medworm.com/index.php?rid=3531060&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20433820%26dopt%3DAbstract Authors: Fanani ML, Maggio B In cell biology (and in many biophysical) studies there is a natural tendency to consider ceramide as a highly condensed, solid-type lipid conferring rigidity and close packing to biomembranes. In the present work we advanced the understanding of the phase behavior of palmitoyl-ceramide restricted to a planar interface using Langmuir monolayers under strictly controlled and known surface packing conditions. Surface pressure-molecular area isotherms were complemented with molecular area-temperature isobars and with observations of the surface topography by Brewster Angle Microscopy. The results described herein indicate that palmitoyl-ceramide can exhibit expanded, as well as condensed phase states. Formation of three phases was found, depending on the surfa... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3531060 Mon, 26 Apr 2010 23:00:00 +0100 3531060 http://www.medworm.com/index.php?rid=3515845&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20420816%26dopt%3DAbstract Authors: Teuber K, Schiller J, Fuchs B, Karas M, Jaskolla TW Due to its sensitivity, the tolerance of impurities and the simplicity of performance, matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is increasingly used to analyze lipids from biological sources. Although its detailed role is not understood so far, the applied matrix has a pronounced effect on the achievable spectrum quality and particularly how sensitive the individual lipid classes are detectable. Different matrix compounds were recently established in the lipid field including 2,5-dihydroxybenzoic acid (DHB), 9-aminoacridine (9-AA), para-nitroaniline (PNA), 2-mercaptobenzothiazole (MBT), and 2-(2-aminoethylamino)-5-nitropyridine (AAN). It is the aim of this paper to comp... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3515845 Thu, 22 Apr 2010 23:00:00 +0100 3515845 http://www.medworm.com/index.php?rid=3483493&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20399763%26dopt%3DAbstract Authors: Klacsová M, Westh P, Balgavý P The volumetric properties of fluid bilayers consisting of dioleoylphosphatidylcholine (DOPC, 96 w%) and dioleoylphosphatidylserine (DOPS, 4 w%) with incorporated saturated n-alkanols (CnOH, n=10-16 is the even number of carbons in alkyl chain) were studied by vibrating tube densitometry. The mixing of DOPC and DOPS was found to be ideal and the molecular volumes of pure lipids V(DOPC) and V(DOPS) are additive in mixed bilayers. The increase of V(DOPS) with temperature was steeper than that of V(DOPC) as quantified by significantly higher coefficient of isobaric thermal expansivity gamma. This difference is supposed to be related to the high thermal expansivity of the serine headgroup. The molecular volumes of lipids and CnOH (V(CnOH)) i... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3483493 Wed, 14 Apr 2010 23:00:00 +0100 3483493 http://www.medworm.com/index.php?rid=3483495&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20398641%26dopt%3DAbstract Authors: Sidahmed-Adrar N, Marchetti C, Bonnefont-Rousselot D, Thariat J, Onidas D, Jore D, Gardes-Albert M, Collin F The oxidative interaction of cytochrome c (Cyt c) with liposomes of PalmitoylLinoleylPhosphatidylCholine (PLPC) initiated by radio-induced free radicals was investigated. Results showed that the peroxidation of PLPC is decreased in the presence of Cyt c, meaning that this latter is the preferential target of hydroxyl radicals. In addition, when Cyt c was incubated with peroxidized PLPC, it was found to be able to decompose hydroperoxides of PLPC into hydroxides. The peroxidase activity of Cyt c proceeded via the opening of the tertiary structure of Cyt c, as suggested by the loss of the sixth coordination bond of the heme-iron. Even if it is known to preferentially inte... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3483495 Mon, 12 Apr 2010 23:00:00 +0100 3483495 http://www.medworm.com/index.php?rid=3483494&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20398642%26dopt%3DAbstract Authors: Ghosh A, Shrivastava S, Dey J The surface activity and self-assembly behavior of zwitterionic amphiphile N-(2-hydroxydodecyl)-L-histidine (C(12)HHis) were studied in phosphate buffers of pH 2 and 13 using surface tension and fluorescence probe techniques, respectively. Transmission electron microscopic images of the aggregates have revealed existence of nano-size vesicles in dilute solutions of both acidic and basic pH. In basic medium, the vesicles are converted to tubular aggregates upon increase of surfactant concentration. The nanotubes undergo phase transition to form elongated or small rod-like micelles at a much higher concentration of the amphiphile. The vesicles and nanotubes were found to become more stable upon addition of 10 mol% of cholesterol. PMID: 20398642 ... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3483494 Mon, 12 Apr 2010 23:00:00 +0100 3483494 http://www.medworm.com/index.php?rid=3468331&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20385112%26dopt%3DAbstract Authors: Costello AL, Alam TM The effect of cholesterol (5-40 mol%) on the magnetic induced orientation of sphingomyelin/cholesterol multilamellar vesicles (MLV) was examined using static solid state (31)P NMR spectroscopy. The orientation was modeled assuming an ellipsoidal deformation of the vesicles and was monitored as a function of cholesterol concentration and temperature. In addition, the static (31)P chemical shift anisotropy (CSA) was used to assess the motional and dynamical changes occurring in the bilayer are reported. An exploration of the factors determining the magnetic orientation in sphingomyelin/cholesterol bilayers from the gel (s(o)) to liquid crystalline (or liquid ordered, l(o)) phases is presented and discussed. PMID: 20385112 [PubMed - as supplied by publish... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3468331 Thu, 08 Apr 2010 23:00:00 +0100 3468331 http://www.medworm.com/index.php?rid=3450144&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20371224%26dopt%3DAbstract Authors: Mannock DA, Lewis RN, McMullen TP, McElhaney RN PMID: 20371224 [PubMed - as supplied by publisher] (Source: Chemistry and Physics of Lipids) Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3450144 Thu, 01 Apr 2010 23:00:00 +0100 3450144 http://www.medworm.com/index.php?rid=3450145&cid=s_34408_162_f&fid=34408&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20362562%26dopt%3DAbstract Authors: Russel AL, Kennedy AM, Spuches AM, Venugopal D, Bhonsle JB, Hicks RP In our laboratory we developed a series of antimicrobial peptides that exhibit selectivity and potency for prokaryotic over eukaryotic cells. (Hicks et al., 2007) Circular Dichroism (CD), isothermal calorimetry (ITC) and calcein leakage assays were conducted to determine the mechanism of lipid binding of a representative peptide 1 (Ac-GF-Tic-Oic-GK-Tic-Oic-GF-Tic-Oic-GK-Tic-KKKK-CONH(2)) to model membranes. POPC liposomes were used as a simple model for eukaryotic membranes and 4:1 POPC:POPG liposomes were used as a simple model for prokaryotic membranes. CD, ITC and calcein leakage data clearly indicate that compound 1 interacts via very different mechanisms with the two different liposome membranes. Compoun... Chemistry and Physics of Lipids journals http://www.medworm.com/rss/comments.php?id=3450145 Tue, 30 Mar 2010 23:00:00 +0100 3450145