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Chemistry and Physics of Lipids

Jasmeet Singh, Miroslav Peric
The interactions of the Alzheimer's β-amyloid peptide, Aβ(25-35), with 18:1 (Δ9-Cis) PC 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), L-α-phosphatidylcholine (EPC), 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DOPG), and L-α-phosphatidylglycerol (EPG) phospholipid vesicles with and without cholesterol (Ch) are studied by the nitroxide spin probe electron paramagnetic resonance (EPR) method. Two nitroxide spin probes, 2,2,6,6-tetramethyl-piperidin-1-oxyl-4-yl hexadecanoate (TP, TEMPO-Palmitate) and 2-Ethyl-2-(15-methoxy-15-oxopentadecyl)-4,4-dimethyl-3-oxazolidinyloxy (16-DSE), are utilized in the study...
September 14, 2018: Chemistry and Physics of Lipids
Fatemeh Haghighi, Vahideh Rabani, Jean-Paul Pais-De-Barros, Siamak Davani
Platelets are major targets for the treatment of thrombo-embolic disorders. Their plasma membrane contains specialized microdomains enriched in sphingomyelins and free cholesterol including membrane receptors. P2Y12 receptors need to be situated in these domains to be able to conduct activation signaling by adenosine diphosphate (ADP). We studied the impact of ticagrelor, a P2Y12 antagonist, and ADP on the composition and distribution of sphingomyelins in detergent-resistant membrane (DRM) of platelet membranes...
September 14, 2018: Chemistry and Physics of Lipids
Rama Prajapati, Stefan Salentinig, Anan Yaghmur
Lyotropic non-lamellar liquid crystalline (LLC) nanoparticles are attractive nanocarriers for drug delivery, particularly for the solubilization of poorly water-soluble drugs. Due to the reported problems of complement activation and cytotoxicity of most investigated Pluronic F127-stabilized cubosomes and hexosomes, there is an interest in introducing safe stabilizers for these LLC nanodispersions. Citrem appears to be the stabilizer of choice for the colloidal stabilization of these LLC nano-self-assemblies owing to its hemocompatiblity and poor activation of the complement system...
September 14, 2018: Chemistry and Physics of Lipids
A Saedi, K Rostamizadeh, M Parsa, N Dalali, N Ahmadi
In this study, we aimed to investigate the influence of liquid lipid types on different features of NLC. Four variations of liquid lipids such as coconut oil, fish oil, black seed oil and linseed oil were used, while for all variations, cetyl palmitate was used as the solid lipid. Different NLC were characterized and compared in terms of particle size, zeta potential, polydispersity index (PDI), drug entrapment percentage and drug loading capacity. The results indicated that NLC containing black seed oil has the smallest size...
September 13, 2018: Chemistry and Physics of Lipids
Maxwell Zeigler, Dale Whittington, Nona Sotoodehnia, Rozenn N Lemaitre, Rheem A Totah
A method for the detection and quantification of hydroxyl and epoxy arachidonic acid (AA) metabolites in human plasma was developed using liquid-liquid extraction, phospholipid saponification followed by derivatization of the acid moiety and liquid chromatographic tandem mass spectrometric detection. Derivatization with a pyridinium analog allowed for detection in the positive ion mode, greatly improving sensitivity and the stability of the more labile AA metabolites. The entire method utilizes a 96-well plate format, increasing sample throughput, and was optimized to measure 5-, 8-, 9-, 11-, 12-, 15-, 19-, and 20- hydroxyeicosatetraenoic acid (HETE), 5,6-, 8,9-, 11,12-, and 14,15- dihydroxyeicosatrienoic acid (DHET), and the regio- and cis-/ trans- isomers of 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acid (EET)...
September 7, 2018: Chemistry and Physics of Lipids
Erhard Bieberich
About twenty years ago, the functional lipid raft model of the plasma membrane was published. It took into account decades of research showing that cellular membranes are not just homogenous mixtures of lipids and proteins. Lateral anisotropy leads to assembly of membrane domains with specific lipid and protein composition regulating vesicular traffic, cell polarity, and cell signaling pathways in a plethora of biological processes. However, what appeared to be a clearly defined entity of clustered raft lipids and proteins became increasingly fluid over the years, and many of the fundamental questions about biogenesis and structure of lipid rafts remained unanswered...
September 5, 2018: Chemistry and Physics of Lipids
Françoise Hullin-Matsuda, Motohide Murate, Toshihide Kobayashi
Sphingomyelin (SM) is a major sphingolipid in mammalian cells whereas its analog, ceramide phosphoethanolamine (CPE) is found in trace amounts in mammalian cells and in larger amounts in invertebrates such as insect cells like Drosophila melanogaster. To visualize endogenous SM or CPE, we need specific probes able to recognize the chemical structure of the lipid, rather than its physical property. A limited number of proteins is known to specifically and strongly bind SM or CPE. These proteins are either toxins produced by non-mammalian organisms, subunits or fragments of toxins or a protein that has similar structure to a toxin...
September 5, 2018: Chemistry and Physics of Lipids
P Bełdowski, N Kruszewska, S Yuvan, Z Dendzik, T Goudoulas, A Gadomski
Functionality of articular cartilage results from complex interactions between its molecular components. Among many biomolecules, two are of prime importance for lubrication: hyaluronic acid (HA) and phospholipids (PL). The purpose of this study is to discuss a mechanism of interaction between these two components and how their synergies contribute to nanobiolubrication of articular cartilage. Preliminary molecular dynamics simulations have been performed to investigate these interactions by adopting a capstan-like mechanism of action...
August 23, 2018: Chemistry and Physics of Lipids
Mark B Frampton, Michael H L Nguyen, Mitchell DiPasquale, Robert Dick, Drew Marquardt, Paul M Zelisko
We have synthesized six new hybrid siloxane phosphocholines (SiPCs) and examined their self-assembly behaviour in aqueous dispersions. Employing small angle X-ray scattering we have characterized SiPC bilayers. SiPCs exhibit differential self-assembly behaviour that results from the interplay between the siloxane fatty acid in the sn-2 position and the differing chain length fatty acids in the sn-1 position. SiPCs that possess a fatty acid chain of a C8 -C14 chain length in the sn-1 position form unilamellar vesicles...
August 9, 2018: Chemistry and Physics of Lipids
Yusuke Yamamoto, Takayuki Furukawa, Seiji Takeda, Hiroyuki Kashida, Hitoshi Chiba, Shu-Ping Hui
Lysophospholipids (LysoPLs) receive steadily increasing attention in the area of lipid chemistry and biology. However, the physico-chemical properties of individual LysoPL regioisomers have not yet been investigated. Herein, we report the synthesis of fluoro analogues of lysophosphatidylethanolamines (LPEs) and examine the physico-chemical properties of the LPE regioisomers using chemically synthesized fluoro probes.
August 3, 2018: Chemistry and Physics of Lipids
Emma K Eriksson, Víctor Agmo Hernández
Liposome solute permeability experiments are widely performed to gain information about lipid membrane characteristics. Spectroscopic methods are often used for this purpose, usually monitoring the leakage of a self-quenching fluorescent dye (e.g., carboxyfluorescein, CF) from the liposomes. Hereby, we investigate the effect of liposome-cuvette interactions, a seldom considered detail, on the results obtained from liposomal permeability experiments. The spontaneous leakage of CF from liposomes with different surface properties and phase states is followed using quartz and polystyrene cuvettes, and the results are compared...
September 2018: Chemistry and Physics of Lipids
Christelle Lopez, Ken Cheng, Javier Perez
Sphingomyelin (SM) and cholesterol are major lipid components of biological membranes involved in the formation of ordered domains. In this study, we investigated the biophysical properties of milk-SM bilayers and determined the effect of cholesterol. The thermotropic phase behaviours of milk-SM and milk-SM/cholesterol mixtures were characterized using differential scanning calorimetry (DSC) and high flux synchrotron radiation X-ray diffraction (SR-XRD). The melting phase transition temperature determined for fully hydrated milk-SM bilayers was Tm  = 34...
September 2018: Chemistry and Physics of Lipids
Eun-Young Park, Taeho Lee, Yoon Sin Oh, Joo-Youn Lee, Jitendra Shrestha, Seung Woo Hong, Yun Ji Jin, GeunHyung Jo, Sanghee Kim, Gil Tae Hwang, Dong-Sul Han, Dong Jae Baek
PF-543 is a non-sphingosine analogue with inhibitory effect against SK1, based on a Ki of 4.3 nM and 130-fold selectivity for SK1 over SK2. Since the development of PF-543, animal studies demonstrated its valuable role in multiple sclerosis, myocardial infarction, and colorectal cancer. We synthesized labeled PF-543 for biochemical studies involving SK1. Overall, the 8-step synthetic route used 3,5-dimethylphenol as the starting material. A docking study of SK1 and SK1 inhibitory activity confirmed the structural similarity between the synthetic dansyl-PF-543 and PF-543...
September 2018: Chemistry and Physics of Lipids
Arun Kumar, Rekha, S K Kansal, A O Ibhadon, S K Mehta
Surface properties and aggregation behavior of cationic-cationic and cationic-non-ionic mixed surfactant systems viz. Dodecylethyldimethylammonium bromide (DDAB) with a series of double chain cationic surfactants (DiDDAB, DMDTAB, and DODAB) and non-ionic surfactants (Brij 96, Tyloxapol and Tween 80) were analysed using surface tension and transmission electron microscopy (TEM). The effect of chain length of cationic surfactant and hydrophilic-lypophilic balance (HLB) prominently observed in critical aggregation (cac) value...
September 2018: Chemistry and Physics of Lipids
Eduardo Izquierdo, Antonio Delgado
The term "click chemistry" was firstly coined by K. B. Sharpless in 2001 to refer to reactions that are high yielding, wide in scope, produce only easily removable byproducts and are stereospecific and simple to perform. Since then, this concept has been further developed and a large number of chemical reactions that fulfil totally or partially these criteria have been identified, contributing to widen the structural diversity in drug discovery campaigns, and providing chemical biologists with invaluable tools for the development of bioorthogonal reactions...
September 2018: Chemistry and Physics of Lipids
Donia Essaid, Ali Tfayli, Philippe Maillard, Christophe Sandt, Véronique Rosilio, Arlette Baillet-Guffroy, Athena Kasselouri
Fourier Transform Infrared (FTIR) microspectroscopy was used to highlight the interactions between two photosensitisers (PS) of different geometries, TPPmOH4 and a glycoconjugated analogous, TPPDegMan, and lipid bilayers modelling retinoblastoma cell membranes. Retinoblastoma is a rare disease occurring in young infants, for whom conservative treatments may present harmful side-effects. Photodynamic therapy (PDT) is expected to induce less side-effects, as the photosensitiser is only activated when the tumour is illuminated...
September 2018: Chemistry and Physics of Lipids
Noah A Schenk, Peter J Dahl, Michael G Hanna, Anjon Audhya, Gregory G Tall, Jefferson D Knight, Arun Anantharam
Fusion and fission of cellular membranes involve dramatic, protein-mediated changes in membrane curvature. Many of the experimental methods useful for investigating curvature sensing or generation require specialized equipment. We have developed a system based on supported lipid bilayers (SLBs) in which lipid tubules are simple to produce and several types of membrane remodeling events can be readily imaged using widely available instrumentation (e.g., tubule fission and/or membrane budding). Briefly, high ionic strength during lipid bilayer deposition results in incorporation of excess lipids in the SLB...
September 2018: Chemistry and Physics of Lipids
Masanao Kinoshita, Kenichi G N Suzuki, Michio Murata, Nobuaki Matsumori
Sphingomyelin (SM)-rich membrane nano-domains, called lipid rafts, have attracted the interest of researchers due to their potential involvement in the formation of signaling platform. Although there are many studies on lipid rafts, the direct observation of lipid rafts is still challenging owing to two critical reasons. One is the lack of an appropriate fluorescent probe mimicking the native behavior of raft lipids; fluorescent labeling often alters the intrinsic disposition of raft lipids. The other is their spatio-temporal stability; the size of lipid rafts is much smaller than the optical resolution of usual microscopy and their lifetime is much shorter than image acquisition duration...
September 2018: Chemistry and Physics of Lipids
G Bhattacharya, R P Giri, A Dubey, S Mitra, R Priyadarshini, A Gupta, M K Mukhopadhyay, S K Ghosh
Ionic liquids (ILs) have generated considerable attention recently because of their cytotoxicity and application as antibiotics. However, the mechanism of how they damage cell membranes is not currently well understood. In this paper, the antibacterial activities of two imidazolium-based ILs, namely 1-butyl- 3-methylimidazolium tetrafluroborate ([BMIM][BF4]) and 1-ethyl- 3-methylimidazolium tetrafluroborate ([EMIM][BF4]) have been investigated. The activity of [BMIM][BF4] on gram negative bacteria E. coli is observed to be stronger compared with the short chained [EMIM][BF4]...
September 2018: Chemistry and Physics of Lipids
Akina Nakaune-Iijima, Akinori Sugishima, Gen Omura, Hiroyuki Kitaoka, Tomoko Tashiro, Shigeki Kageyama, Ichiro Hatta
Long-periodicity phase (LPP) lamellar structures in intercellular lipid matrixes of the stratum corneum (SC) are considered important for maintenance of skin permeability barriers. Acylceramides are essential components of LPP structures, and their absence influences skin barriers under physiological and pathological conditions, such as atopic dermatitis and dry skin. Although topical applications of acylceramide have been shown to facilitate maintenance of the skin barrier, it is unknown whether topically applied acylceramides are incorporated into intercellular lipids to form LPP structures...
September 2018: Chemistry and Physics of Lipids
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