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Chemistry and Physics of Lipids

Su-Min Han, Jong-Suep Baek, Min-Soo Kim, Sung-Joo Hwang, Cheong-Weon Cho
Liposomes can achieve a controlled release and an improved bioavailability of water- insoluble drug with minimized side effects. Paclitaxel is an efficient anticancer drug for the treatment of various cancers. However, paclitaxel has a solubility of 0.5 mg/L in water and a low bioavailability of 6.5%. Moreover, paclitaxel is a substrate for p-glycoprotein, which shows a decreased accumulation of drug within the cancer cell expressed by a p-glycoprotein. Therefore, the purpose of this study is to prepare a paclitaxel-loaded liposome and evaluate the effect of d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) as an inhibitor of p-glycoprotein on the paclitaxel-loaded liposome...
March 14, 2018: Chemistry and Physics of Lipids
Gopinath Viswanathan, Md Jafurulla, G Aditya Kumar, Tirumalai R Raghunand, Amitabha Chattopadhyay
Mycobacteria are intracellular pathogens that can invade and survive within host macrophages. Mycobacterial infections remain a major cause of mortality and morbidity worldwide, with serious concerns of emergence of multi and extensively drug-resistant tuberculosis. While significant advances have been made in identifying mycobacterial virulence determinants, the detailed molecular mechanism of internalization of mycobacteria into host cells remains poorly understood. Although several studies have highlighted the crucial role of sphingolipids in mycobacterial growth, persistence and establishment of infection, the role of sphingolipids in the entry of mycobacteria into host cells is not known...
March 8, 2018: Chemistry and Physics of Lipids
Georg Hölzl, Christian Sohlenkamp, Miguel Angel Vences-Guzmán, Nicolas Gisch
Amino acid-containing acyloxyacyl lipids are composed of a 3-hydroxy fatty acid amide-bound to the α-amino group of an amino acid. A second fatty acid is ester-linked to the 3-hydroxy group of the first fatty acid. Most commonly, ornithine is the headgroup of these lipids, but glycine, serineglycine, glutamine and lysine have also been described in bacteria. Ornithine lipids (OL) can be synthesized by about 50% of the sequenced bacterial species, and several covalent modifications of its basic structure have been described...
March 7, 2018: Chemistry and Physics of Lipids
Feroz Ahmad, David S Leake
Oxidised low density lipoprotein (LDL) was considered to be important in the pathogenesis of atherosclerosis, but the large clinical trials of antioxidants, including the first one using probucol (the PQRST Trial), failed to show benefit and have cast doubt on the importance of oxidised LDL. We have shown previously that LDL oxidation can be catalysed by iron in the lysosomes of macrophages. The aim of this study was therefore to investigate the effectiveness of antioxidants in preventing LDL oxidation at lysosomal pH and also establish the possible mechanism of oxidation...
March 5, 2018: Chemistry and Physics of Lipids
Lorale J Lalgee, Leonette Cox, Richard A Fairman, Lebert Grierson
A novel series of amphiphilic cobalt-cage derivatives (ACCD), bearing a diaza-crown bridge and varying alkyl chains, facilitate ion transport across biomembrane models via self-aggregation. In this study, compression isotherm analyses and atomic force microscopy (AFM) were used to assess the interactions of these amphiphiles with Langmuir monolayers of dipalmitoylphosphatidylcholine (DPPC) in order to elucidate electrostatic and steric contributions to ion transport. The stability and compressibility of DPPC monolayers are disrupted by ACCD molecules with short (C12 ) alkyl chains...
February 27, 2018: Chemistry and Physics of Lipids
Md Mizanur Rahman Moghal, Md Zahidul Islam, Sabrina Sharmin, Victor Levadnyy, Md Moniruzzaman, Masahito Yamazaki
Entry of cell-penetrating peptides (CPPs) into living cells by translocating across plasma membranes is an important physiological phenomenon. To elucidate the mechanism of the translocation of CPPs across lipid bilayers, it is essential to reveal its elementary processes. For this purpose, here, we have developed a new method for the continuous, quantitative detection of the entry of CPPs into giant unilamellar vesicles (GUVs), where we investigate the interaction of fluorescent probe-labeled CPPs with single GUVs containing large unilamellar vesicles (LUVs) and fluorescent probes in their lumens using confocal microscopy...
February 6, 2018: Chemistry and Physics of Lipids
Monique B Ewonkem, Sarina Grinberg
Based on ricinoleic acid, two asymmetric bolaamphiphiles with unsymmetrical hydrophobic skeletons and two different hydrophilic head groups were designed and synthesized. The first bola compound had acetylcholine (ACh) and maleimide (MAL) head groups while the second was derived from the first bolaamphiphile by thiol-ene conjugation of its maleimide moiety with l-glutathione and possessed ACh and l-glutathione-MAL head groups. Both synthetic bolaamphiphiles were characterized by common spectroscopic methods...
February 2, 2018: Chemistry and Physics of Lipids
Maria Oranges, Rita Guzzi, Derek Marsh, Rosa Bartucci
Electron spin echo envelope modulation (ESEEM) and conventional electron paramagnetic resonance (EPR) of site-specifically spin-labelled phospholipids are used to investigate the effect of ether-linked chains on the water-penetration and polarity profiles, as well as the phase behaviour and chain flexibility profiles, of phospholipid membranes. D2O-ESEEM reveals that water exposure of the terminal methyl groups in the interdigitated phase of dihexadecyl phosphatidylcholine (DHPC) is comparable to that of the methylene groups at the polar head-group end of the chains...
February 1, 2018: Chemistry and Physics of Lipids
Mojtaba Tabandeh, Abbas Abdulameer Salman, Ean Wai Goh, Thorsten Heidelberg, Rusnah Syahila Duali Hussen
A new synthesis approach towards biantennary lipids of Guerbet glycoside type was developed based on oleic acid as sustainable resource. Functionalization of the double bond provided access to primary alcohols with α-branched C19-skeleton. Formulation studies with corresponding lactosides indicated formation of vesicles with high assembly stability. A relatively narrow bimodal size distribution of the latter, which turns into a narrow unimodal distribution of small vesicles upon addition of an ionic cosurfactant, suggests potential for a vesicular drug delivery system...
January 31, 2018: Chemistry and Physics of Lipids
Dominik Drabik, Joanna Doskocz, Magda Przybyło
Giant unilamellar vesicles (GUVs) have become one of extensively studied biological bilayer models especially when investigating topological and mechanical properties of cell membranes. They are also used to visualize membrane-related phenomena. However, the method of preparation and the effects of parameters of preparation on the vesicular structure are extensively varied. Therefore, it is important to understand how the process of formation of GUVs influences the outcome population, as it can influence the outcome of the experiment that is planned...
January 31, 2018: Chemistry and Physics of Lipids
Guilherme A Calligaris, Thais L T da Silva, Ana Paula B Ribeiro, Adenilson O Dos Santos, Lisandro P Cardoso
The characterization of fat components becomes very useful for formulation of shortening, margarines and fat products due to their unique properties of plasticity, texture, solubility, and aeration. However, X-ray diffraction experiments on such materials are usually limited to a qualitative evaluation of the polymorphic properties based only on the characteristic d-spacing peak intensities. In this work, interesting results based on the Rietveld Method have supported both a Quantitative Phase Analysis and Degree of Crystallinity study on industrial and academic appealing samples, such as triacylglycerol standards, fully hydrogenated vegetable oils (hardfats) and cocoa butter...
January 20, 2018: Chemistry and Physics of Lipids
Mohamed Elderdfi, Aleksander F Sikorski
The Langmuir-monolayer technique is a convenient method that allows for continuous control over several membrane-specific parameters, such as molecular packing, physical states, lateral pressure and lipid composition. Lipid monolayers are well suited for applications involving the Langmuir-monolayer technique: they are very well-defined, stable, homogeneous and two-dimensional, and they have planar geometry. In this review, some features of monolayer methodologies based on the Langmuir-monolayer technique are described, with a focus on the step-wise procedures that can be applied to characterize protein-lipid interactions at the lipid monolayer/buffer interface in order to maximize the information concerning the mechanism of interaction between the protein and the lipid monolayer...
January 19, 2018: Chemistry and Physics of Lipids
Martine Moulin, Gernot A Strohmeier, Melanie Hirz, Katherine C Thompson, Adrian R Rennie, Richard A Campbell, Harald Pichler, Selma Maric, V Trevor Forsyth, Michael Haertlein
Deuteration of biomolecules has a great impact on both quality and scope of neutron scattering experiments. Cholesterol is a major component of mammalian cells, where it plays a critical role in membrane permeability, rigidity and dynamics, and contributes to specific membrane structures such as lipid rafts. Cholesterol is the main cargo in low and high-density lipoprotein complexes (i.e. LDL, HDL) and is directly implicated in several pathogenic conditions such as coronary artery disease which leads to 17 million deaths annually...
January 18, 2018: Chemistry and Physics of Lipids
Chandra Has, Sopan M Phapal, P Sunthar
Laboratory preparation of unilamellar liposomes often involves multiple steps carried out over several hours to achieve a monodisperse size distribution. Here we present a methodology, based on a recently introduced lipid self-assembly principle-stationary phase interdiffusion (SPI)-to prepare large unilamellar vesicles (LUVs) of a monodisperse population in a short period of about 10min. The stationary interface between a lipid-ethanol phase and an aqueous phase is created by a density difference induced convective flow in a horizontal capillary...
January 17, 2018: Chemistry and Physics of Lipids
Samuel C R Sherratt, R Preston Mason
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) differentially influence lipid oxidation, signal transduction, fluidity, and cholesterol domain formation, potentially due in part to distinct membrane interactions. We used small angle x-ray diffraction to evaluate the EPA and DHA effects on membrane structure. Membrane vesicles composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and cholesterol (C) (0.3C:POPC mole ratio) were prepared and treated with vehicle, EPA, or DHA (1:10 mole ratio to POPC)...
January 17, 2018: Chemistry and Physics of Lipids
Francisco Fermin Castro Navas, Gianluca Giorgi, Daniela Maggioni, Manuela Pacciarini, Vincenzo Russo, Maura Marinozzi
Phytosterols are stucturally correlated to the endogenous ligands of Liver X Receptor (LXR), a ligand-activated nuclear receptor that has emerged as an attractive drug target due to its ability to integrate metabolic and inflammatory signaling. Natural and semi-synthetic phytosterol derivatives characterized by the presence of side-chain oxygenated functions have shown to be able to modulate LXR activity. Here, we describe the efficient synthesis of four stigmastane derivatives, endowed with a hydroxyl group at C24 position, namely (24R)- and (24S)-stigmasta-5,28-diene-3β,24-ols (also referred to as saringosterols, 10a and 10b) and (24R)- and (24S)-stigmasta-5-ene-3β,24-ols (11a and 11b), starting from the readily available stigmasterol...
January 15, 2018: Chemistry and Physics of Lipids
Kyu-Ho Song, Min-Young Lee, Chi-Hyeon Yoo, Song-I Lim, Bo-Young Choe
Proton magnetic resonance spectroscopy (MRS) with optimized relaxation time is an effective method to quantify hepatic fatty acid values and characterize steatosis. The aim of this study is to quantify the difference in hepatic lipid content with metabolic changes during the progression of steatosis by using localized MRS sequence with T2 relaxation time determination. Fatty liver disease was induced in C57BL/6N mice through a high-fat diet (HFD) of pellets containing 60% fat, 20% protein, and 20% carbohydrates...
January 11, 2018: Chemistry and Physics of Lipids
Mahantesh Jadhav, Rahul S Kalhapure, Sanjeev Rambharose, Chunderika Mocktar, Sanil Singh, Tetsuya Kodama, Thirumala Govender
The acidic environment at bacterial infection sites is a potential external stimulus for targeted antibiotic delivery. This paper reports new biocompatible pH-sensitive lipids (PSLs) with three hydrocarbon tails, and a head group with a secondary amine and carboxylate function for site-specific nano delivery of vancomycin (VCM). PSLs formed stable liposomes with mean vesicle diameters and polydispersity indices between 99.38 ± 6.59 nm to 105.60 ± 5.38 nm and 0.161 ± 0.003 to 0.219 ± 0...
January 2, 2018: Chemistry and Physics of Lipids
Marta Llorens-Fons, Esther Julián, Marina Luquin, Míriam Pérez-Trujillo
Mycobacterium smegmatis is often used to study the different components of mycobacterial cell wall. Mycolic acids are important components of mycobacterial cell wall that have been associated with virulence. Recently, a novel lipid containing mycolic acids has been described in M. smegmatis. However, some uncertainties regarding the structure of this molecule named mycolate ester wax have been reported. The objective of this work was to perform an in depth structural study of this molecule for its precise characterization...
December 29, 2017: Chemistry and Physics of Lipids
M Padariya, U Kalathiya, M Baginski
EmrE is a bacterial transporter protein that forms an anti-parallel homodimer with four transmembrane helices in each monomer. EmrE transports positively charged aromatic compounds, such as TPP+ and its derivatives. We performed molecular dynamics (MD) simulations of EmrE in complex with TPP+, MeTPP+, and MBTPP+ embedded in a membrane. The detailed molecular properties and interactions were analysed for all EmrE-ligand complexes. Our MD results identified that Lys22, Tyr40, Phe44, Trp45, and Trp63 formed potential π interactions with all three ligands and further confirmed the essential role of Glu14...
December 27, 2017: Chemistry and Physics of Lipids
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