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Chemistry and Physics of Lipids

Carolina Abril-Sánchez, Adrián Matencio, Silvia Navarro-Orcajada, Francisco García-Carmona, José Manuel López-Nicolás
In this work we used natural and modified cyclodextrins (β-CD and HP-β-CD) as encapsulating agents to improve citronellal properties. Using fluorimetric techniques, its aggregation behavior was studied for the first time. Its critical micellar concentration was seen to vary with the presence of cyclodextrins, which form 1:1 stoichiometry complexes with citronellal. The encapsulation constants and the scores obtained by Molecular Docking were correlated. Chromatographic (GC-MS) and sensory analysis confirmed that cyclodextrins improve the persistence of the aroma...
February 11, 2019: Chemistry and Physics of Lipids
M G Karlova, N Voskoboynikova, G S Gluhov, D Abramochkin, O A Malak, A Mulkidzhanyan, G Loussouarn, H-J Steinhoff, K V Shaitan, O S Sokolova
Styrene-maleic acid (SMA) copolymers are used to extract lipid-encased membrane proteins from lipid bilayers in a detergent-free manner, yielding SMA lipid particles (SMALPs). SMALPs can serve as stable water-soluble nanocontainers for structural and functional studies of membrane proteins. Here, we used SMA copolymers to study full-length pore-forming α-subunits hKCNH5 and hKCNQ1 of human neuronal and cardiac voltage-gated potassium (Kv) channels, as well as the fusion construct comprising of an α-subunit hKCNQ1 and its regulatory transmembrane KCNE1 β-subunit (hKCNE1-hKCNQ1) with added affinity tags, expressed in mammalian COS-1 cells...
January 31, 2019: Chemistry and Physics of Lipids
Evgeniy S Salnikov, Christopher Aisenbrey, G M Anantharamaiah, Burkhard Bechinger
The membrane topology of the peptide 18 A, a derivative of apolipoprotein A-I, is investigated in structural detail. Apolipoprotein A-I is the dominant protein component of high density lipoproteins with important functions in cholesterol metabolism. 18 A (Ac-DWLKA FYDKV AEKLK EAF- NH2 ) was designed to mimic the structure of tandem domains of class A amphipathic helices and has served as a lead peptide for biomedical applications. At low peptide-to-lipid ratios 18 A partitions into phosphatidylcholine membranes with helix topologies parallel to the membrane surface, an alignment that is maintained when disc-like bicelles form at higher peptide-to-lipid ratios...
January 31, 2019: Chemistry and Physics of Lipids
Diógenes de Queiroz Dias, Débora Lima Sales, Jacqueline Cosmo Andrade, Ana Raquel Pereira da Silva, Saulo Relison Tintino, Cícera Datiane de Morais Oliveira-Tintino, Gyllyandeson de Araújo Delmondes, Marcos Fábio Gadelha Rocha, José Galberto Martins da Costa, Rômulo Romeu da Nóbrega Alves, Felipe Silva Ferreira, Henrique Douglas Melo Coutinho, Waltécio de Oliveira Almeida
The bioprospection of zootherapeutic products can be a source of new drugs and to the creation of new strategies of natural resources conservation and management of endangered species. This fact is supported by ethnobiological studies indicating that the usage of zootherapeutic products can be replaced by the use of natural products isolated from plants and domestic animals. The emergence of antibiotic-resistant bacteria has increased the need for research for new active principles. Ethnoveterinary studies in Brazil have shown that Sus scrofa domesticus fat is used for diseases associated with bacterial pathogens...
January 30, 2019: Chemistry and Physics of Lipids
C Roger White, Geeta Datta, Landon Wilson, Mayakonda N Palgunachari, G M Anantharamaiah
High density lipoprotein (HDL) is prone to modification by the oxidizing and chlorinating agent hypochlorite anion (OCl-). Oxidation of apolipoprotein (apo)A-I, the major protein in HDL, reduces ABCA-1 mediated cholesterol efflux and other protective responses to HDL. The apoA-I mimetic peptide 4F has been shown to undergo oxidation; however, the ability of the peptide to mediate cholesterol efflux remains intact. Here, we show that 4F protects apoA-I from hypochlorite-mediated oxidation. Mass spectral analysis of apoA-I shows that tyrosine residues that are prone to hypochlorite-mediated chlorination are protected in the presence of 4F...
January 29, 2019: Chemistry and Physics of Lipids
Thirupathi Ravula, Nathaniel Z Hardin, Ayyalusamy Ramamoorthy
There is considerable interest in the development of membrane mimetics to study the structure, dynamics and function of membrane proteins. Polymer nanodiscs have been useful as a membrane mimetic by not only providing a native-like membrane environment, but also have the ability to extract the desired membrane protein directly from the cell membrane. In spite of such great potential, polymer nanodiscs have their disadvantages including lack of size control and instability at low pH and with divalent metals...
January 29, 2019: Chemistry and Physics of Lipids
Izumi Yamane, Ayano Momose, Hideki Fujita, Eri Yoshimoto, Akie Kikuchi-Kinoshita, Izuru Kawamura, Akira Naito
Glucagon is a 29 amino acid peptide hormone secreted by pancreatic α-cells and interacts with specific receptors located in various organs. Glucagon tends to form gel-like fibril aggregates that are cytotoxic because they activate apoptotic signaling pathways. To understand mechanism of fibril formation, we investigated the structure and kinetics of glucagon fibril formation using 13 C solid-state NMR spectroscopy. In aqueous acetic acid solution at pH 3.3, distorted α-helical structure appeared around Gly4, Leu14, Ala19 and Leu26 in the monomeric form...
January 25, 2019: Chemistry and Physics of Lipids
Kelly M Hines, Libin Xu
Our understanding of phospholipid biosynthesis in Gram-positive and Gram-negative bacteria is derived from the prototypical Gram-negative organism Escherichia coli. The inner and outer membranes of E. coli are largely composed of phosphatidylethanolamine (PE), minor amounts of phosphatidylglycerol (PG) and cardiolipin (CL). We report here the utility of hydrophilic interaction liquid chromatography (HILIC) paired with ion mobility-mass spectrometry (IM-MS) for the comprehensive analysis of the E. coli lipidome...
January 17, 2019: Chemistry and Physics of Lipids
Wenjiao Xiao, Qiuyi Fu, Yi Zhao, Li Zhang, Qiming Yue, Li Hai, Li Guo, Yong Wu
In this study, a novel brain targeting ascorbic acid (AA) derivative with "lock-in" function was designed and synthesized as a liposome ligand to prepare novel liposomes to achieve the effective delivery of drug formulations to brain via glucose transporter 1 (GLUT1 ) and the Na+ -dependent vitamin C transporter (SVCT2 ). The liposome was prepared and characterized in terms of the particle size, zeta potential, encapsulation efficiency, release profile, stability, hemolysis and cell cytotoxicity. The preliminary evaluation in vivo demonstrated that the AA-thiamine disulfide system (TDS)-coated liposome had an improved targeting ability and significantly increased the brain concentration of docetaxel (DTX) as compared to the naked docetaxel, the non-coated and the AA-coated liposomes...
January 17, 2019: Chemistry and Physics of Lipids
Kumiko Sakai-Kato, Kohki Yoshida, Ken-Ichi Izutsu
Here we report that the size dependence of cellular internalization of liposomes differs depending on the surface charge. We prepared liposomes of various lipid compositions ranging from 100 to 200 nm size. It was found that cationic liposomes composed of 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-Dioleoyl-3-trimethylammonium-propane (DOTAP) were most effectively internalized into cells when their mean particle sizes were around 180 nm. When their size was reduced to around 90 nm, the level of internalization reduced six-fold...
January 17, 2019: Chemistry and Physics of Lipids
Ananya Singh, Farhan Ahmad, Priti Bajpai, Tarique Mahmood Ansari, Aisha Kamal
Cyanobacteria are the most primitive, oxygen-evolving prokaryotic organism. Several, conspicuous investigations have been done around lipids from cyanobacteria. However, to date and to the best of our knowledge, no study was conducted to formulate and evaluate liposomal vesicles prepared from cyanobacterial lipid. In the present study, cyanosomes were formulated using natural lipids extracted from the cyanobacterium Synechococcus elongatus PCC7942 which were further loaded with thymoquinone. The results showed that the prepared cyanosomes were homogenous with an overall negative charge of particle size ranging between 200 to 210 nm and entrapment efficacy was 70...
January 17, 2019: Chemistry and Physics of Lipids
Jianzhong Chen, Shyam Panthi
Lipids secreted from the meibomian glands form the outermost layer of the tear film and reduce its evaporation. Abnormal changes in the quantities or compositions of lipids present in meibomian gland secretions (meibum) are known to lead to dry eye disease, although the underlying mechanism is not yet well understood. The tree shrew is the non-primate mammal most closely related to humans. To assess the utility of the tree shrew as a model for the study of dry eye disease, we analyzed the lipid profile of tree shrew meibum using an untargeted ESI-MS and MS/MSall shotgun approach...
January 17, 2019: Chemistry and Physics of Lipids
Chiara Luberto, John D Haley, Maurizio Del Poeta
In the last ten years, mass spectrometry (MS) has become the favored analytical technique for sphingolipid (SPL) analysis and measurements. Indeed MS has the unique ability to both acquire sensitive and quantitative measurements and to resolve the molecular complexity characteristic of SPL molecules, both across the different SPL families and within the same SPL family. Currently, two complementary MS-based approaches are used for lipid research: analysis of lipid extracts, mainly by infusion electrospray ionization (ESI), and mass spectrometry imaging (MSI) from a sample surface (i...
January 11, 2019: Chemistry and Physics of Lipids
Omar T Ali, Mohsin O Mohammed, Paul J Gates, Mark S Baird, Juma'a R Al Dulayymi
Complex mixtures of natural dimycoloyl diarabinoglycerols isolated from mycobacteria have been shown to be both potent immune signalling agents and potentially valuable antigens in the serodiagnosis of mycobacterial infections. We now report the highly stereocontrolled synthesis of diacyl L-glycerol-(1'→1)-β-D-arabinofuranosyl-α-D-arabinofuranosides based on simple fatty acids and single defined synthetic mycolic acids. NMR analysis confirmed that the synthetic core was identical to that in natural mixtures...
January 9, 2019: Chemistry and Physics of Lipids
H Ahumada-Gutierrez, D A Peñalva, R D Enriz, S S Antollini, J J López Cascales
Sphingomyelins (SM) and ceramides (Cer) with very long chain polyunsaturated fatty acids (V) are important components of spermatozoa membranes. In this study, the mechanical properties of bilayers of SM and Cer with nonhydroxy (n-V) and 2-hydroxy (h-V) fatty acid (30:5) were studied by molecular dynamics simulation at different temperatures and in the presence and the absence of salt. From our results, it was evidenced how n-V SM and h-V SM bilayers showed similar behavior. When n-V Cer was added to a h-V SM bilayer, the Gaussian curvature modulus and Ecurve of binary bilayers decreased...
January 2, 2019: Chemistry and Physics of Lipids
Yuan Gao, Shimin Wu, Renhuai Cong, Junyong Xiao, Fangli Ma
Schisandra chinensis is a medicinal and edible plant that contains various bioactive compounds. Among these, lignans are the major functional compounds. Nevertheless, detailed information about lignans in Schisandra chinensis oil remains scarce. A powerful UPLC-Q/TOF-MS method was established for the rapid identification of the lignan constituents of Schisandra chinensis oils. The results showed that 21 lignans have been unambiguously identified, and four lignans have been tentatively identified in the Schisandra chinensis oils...
January 2, 2019: Chemistry and Physics of Lipids
Sarah E Hancock, Alan T Maccarone, Berwyck L J Poad, Adam J Trevitt, Todd W Mitchell, Stephen J Blanksby
Cholesterol is an ubiquitous membrane lipid, that also serves as a precursor to many steroid hormones. The 5,6 carbon-carbon double bond on the tetracyclic carbon backbone of cholesterol is an attractive target for ozone with the reaction giving rise to a wide range of possibly bioactive molecules. Despite this, little is known about the ozonolysis of cholesterol esters, which often possess an additional double bond(s) on the fatty acyl chain. Understanding the intrinsic gas phase reaction of ozone with the two disparate double bond positions on cholesteryl esters can inform our understanding of these processes in vivo, particularly reactions occurring at the air-water interface (e...
December 28, 2018: Chemistry and Physics of Lipids
John F Nagle, Pierre Cognet, Fernando G Dupuy, Stephanie Tristram-Nagle
High resolution low angle x-ray data are reported for the gel phase of DPPC lipid bilayers, extending the previous q range of 1.0 Å-1 to 1.3 Å-1 , and employing a new technique to obtain more accurate intensities and form factors |F(q)| for the highest orders of diffraction. Combined with previous wide angle x-ray and volumetric data, a space filling model is employed to obtain gel phase structure at a mesoscopic level. This analysis provides direct evidence that the hydrocarbon chains from opposing monolayers are mini-interdigitated, consistent with the previously well-established result that the opposing monolayers are strongly coupled with respect to their chain tilt directions...
December 26, 2018: Chemistry and Physics of Lipids
Samuel I Mattern-Schain, Richard K Fisher, Philip C West, Lauren B Grimsley, Taylor M Harris, Oscar H Grandas, Michael D Best, Deidra J H Mountain
No abstract text is available yet for this article.
December 21, 2018: Chemistry and Physics of Lipids
F Corrales Chahar, S B Díaz, A Ben Altabef, C A Gervasi, P E Alvarez
Lipid bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) were prepared in two forms, as a suspension of multilamellar spherical vesicles and as planar membranes deposited on a conductive solid support. We used Fourier Transformed Infrared (FTIR) and Raman spectroscopic techniques to study the lipid vesicles while the solid supported bilayers were characterized by using electrochemical experiments (cyclic voltammetry and impedance). Valproic acid (Valp) was either present in the solution or incorporated into the lipid structure...
December 21, 2018: Chemistry and Physics of Lipids
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