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Chemistry and Physics of Lipids

Eduardo Mateos-Diaz, Priscila Sutto-Ortiz, Moulay Sahaka, Jorge A Rodriguez, Frédéric Carrière
Usual methods for the continuous assay of lipolytic enzyme activities are mainly based on the titration of free fatty acids, surface pressure monitoring or spectrophotometry using substrates labeled with specific probes. These approaches only give a partial information on the chemistry of the lipolysis reaction and additional end-point analyses are often required to quantify both residual substrate and lipolysis products. We used transmission infrared (IR) spectroscopy to monitor simultaneously the hydrolysis of phospholipids by guinea pig pancreatic lipase-related protein 2 (GPLRP2) and the release of lipolysis products...
November 11, 2017: Chemistry and Physics of Lipids
Maria Wadsäter, Justas Barauskas, Fredrik Tiberg, Tommy Nylander
The effects of different lipolytic enzymes on the structure of lipid liquid crystalline nano-particles (LCNP) have been investigated by cryogenic transmission electron microscopy (cryo-TEM) and synchrotron small angle X-ray diffraction (SAXD). Here we used highly structured cubic micellar (Fd3m) nanoparticles of 50/50 (wt%/wt%) soy phosphatidyl choline (SPC)/glycerol dioleate (GDO) as substrate. Two types of lipolytic enzymes were used, phospholipase A2 (PLA2) that catalysis degradation of the phospholipid component, SPC, and porcine pancreatic triacylglycerol lipase (TGL) that facilitate the hydrolysis of the diglyceride, GDO...
November 10, 2017: Chemistry and Physics of Lipids
Kentaro Suzuki, Koichiro Machida, Kazuo Yamaguchi, Tadashi Sugawara
Here, we used centrifugal precipitation to construct a giant vesicle (GV) encapsulating smaller giant vesicles (GV-in-GV) which comprises a photo-resistant outer GV and a photo-pierceable inner GV; the outer GV contained a fluorescent probe (SYBR Green I) in its inner water pool, and the inner GV contained double-stranded DNA (dsDNA) in its inner water pool. The phospholipid membrane of the inner GV was made photo-pierceable by inclusion of ca. 15mol% of a caged phospholipid in its membrane. Immediately after exposure of the GV-in-GVs to UV irradiation, strong fluorescence was detected in the inner water pool of the outer GV, indicating that dsDNA had been released from the inner GV and had complexed with the fluorescent probe...
November 9, 2017: Chemistry and Physics of Lipids
K S Joshy, S Snigdha, George Anne, Kalarikkal Nandakumar, Pothen Laly A, Thomas Sabu
Zidovudine (AZT) is an antiviral drug with moderate solubility in water. It has limited application due to its short half life in vivo and consequent requirement for frequent administrations. To solve this problem, zidovudine loaded polyvinylpyrrolidone (PVP)/stearic acid (SA)-polyethylene glycol (PEG) nanoparticles (PSNPs) were developed.The hybrid nanoparticles were prepared by emulsification-solvent evaporation method. The physico chemical characterizations of the PSNPs was done by dynamic light scattering (DLS), transmission electron microscopy (TEM), and fourier transform infra-red spectroscopy (FT-IR)...
November 9, 2017: Chemistry and Physics of Lipids
Arne Stamm, Allan Svendsen, Jakob Skjold-Jørgensen, Thomas Vissing, Ida Berts, Tommy Nylander
In spite of the importance of the triglyceride aqueous interface for processes like emulsification, surfactant interactions and lipase activity, relatively little is known about this interface compared to that between alkanes and water. Here, the contact between triolein and water was investigated in terms of water inclusion in the oil phase and orientation of the molecules at the interface. Coarse grained models of triglycerides in contact with water were constructed and correlated with experimental results of the changes in thickness and refractive index, obtained using spectroscopic ellipsometry of spin-coated triolein films...
November 9, 2017: Chemistry and Physics of Lipids
Baoliang Ma, Xiaofei Wang, Yujie Liu, Zhihong Li, Yujie Liu, Fan Zhang
Protein aggregation is a prevalent phenomenon. It is important to study protein aggregation under different solution conditions. In this study, using 1-anilinonaphthalene-8-sulfonic acid (ANS) fluorescence spectra, we investigated the critical micelle concentration (CMC) of 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP). We also studied the effects of DOTAP on amyloid aggregation of β-lactoglobulin using intrinsic fluorescence spectra, circular dichroism spectra, thioflavin T fluorescence, a Congo red binding assay and transmission electron microscopy...
November 8, 2017: Chemistry and Physics of Lipids
Shilpa Sonti, Richard I Duclos, Mansi Tolia, Samuel J Gatley
N-Docosahexaenoylethanolamine (synaptamide) is structurally similar to the endocannabinoid N-arachidonoylethanolamine (anandamide), but incorporates the omega-3 22:6 fatty acid docosahexaenoic acid (DHA) in place of the omega-6 20:4 fatty acid arachidonic acid (AA). Some brain membrane lipid effects may be mediated via synaptamide. In competition experiments with mouse brain homogenate in vitro, we found that synaptamide was an order-of-magnitude poorer inhibitor of radioactive anandamide hydrolysis than was anandamide itself...
November 7, 2017: Chemistry and Physics of Lipids
Ryo Yamauchi, Tomomi Kinoshita, Yoshinori Hasegawa, Satoshi Iwamoto
The secondary process of lipid peroxidation proceeds by the free radical reaction to produce some toxic aldehydes. Since γ-tocopherol (γ-TH), one of the major forms of vitamin E in some vegetable oils, acts as a free radical scavenger, γ-TH may suppress the formation of such aldehydes. This study reports the effect and reaction products of γ-TH on the hemin- or myoglobin-catalyzed decomposition of 1-palmitoyl-2-linoleoyl-3-sn-phosphatidylcholine 13-hydroperoxide (PLPC-OOH) in micelles and liposomes. γ-TH and PLPC-OOH in micelles were reacted in the presence of hemin, and the reaction products were characterized as 1-palmitoyl-2-[(8a-dioxy-γ-tocopherone)-12,13-epoxyoctadecenoyl]-3-sn-phosphatidylcholines (γT-OO-epoxyPLPC), 1-palmitoyl-2-[(γ-tocopheroxy)-12,13-epoxyoctadecenoyl]-3-sn-phosphatidylcholines (γT-epoxyPLPC), and the adducts of γ-TH dimer with PLPC-OOH derived epoxyperoxyl and epoxyalkyl radicals (γTD-OO-epoxyPLPC and γTD-epoxyPLPC)...
November 7, 2017: Chemistry and Physics of Lipids
Jonatan Hall-Andersen, Svend G Kaasgaard, Christian Janfelt
Most modern laundry detergents contain enzymes such as proteases, amylases, and lipases for more efficient removal of stains containing proteins, carbohydrates, and lipids during wash at low temperature. The function of the lipases is to hydrolyse the hydrophobic triglycerides from fats and oils to the more hydrophilic lipids diglycerides, monoglycerides and free fatty acids. Here, we use MALDI imaging to study the effect of enzymatic degradation of triglycerides by lipases directly on the textile surface. Textile samples were created by using swatches of different textile blends, adding a lipid stain and simulating washing cycles using well-defined detergents with lipase concentrations ranging between 0 and 0...
November 6, 2017: Chemistry and Physics of Lipids
Elena Ermakova, Yuriy Zuev
Cell membranes are complex multicomponent systems consisting of thousands of different lipids with numerous embedded membrane proteins and many types of sterols. We used all-atom and coarse-grained molecular dynamics simulations to study the structural and dynamical properties of phospholipid bilayers containing four types of phospholipids and different amount of ergosterol, main sterol component in the fungal membranes. To characterize the influence of ergosterol on the membrane properties we analyzed the surface area per lipid, bilayer thickness, area compressibility modulus, mass density profiles, deuterium order parameters, and lateral diffusion coefficients...
November 6, 2017: Chemistry and Physics of Lipids
Thomas Schmitt, Stefan Lange, Stefan Sonnenberger, Bodo Dobner, Bruno Demé, Reinhard H H Neubert, Gert Gooris, Joke A Bouwstra
This study was able to investigate the different influence of the d- and l-ceramide [AP] on the lamellar as well as molecular nanostructure of stratum corneum simulating lipid model mixtures. In this case, neutron diffraction together with specifically deuterated ceramide was used as an effective tool to investigate the lamellar and the molecular nanostructure of the mixtures. It could clearly be demonstrated, that both isomers show distinctly different characteristics, even though the variation between both is only a single differently arranged OH-group...
November 4, 2017: Chemistry and Physics of Lipids
Brittany M Neumann, Devin Kenney, Qi Wen, Arne Gericke
This work describes a method that utilizes a microfluidic gradient generator to develop lateral lipid gradients in supported lipid bilayers (SLB). This methodology that we have developed provides freedom of choice with respect to the lipid composition as well as the shape of the lipid gradient. For instance, the steepness of the gradient, within certain limits of its functional behavior, can be chosen based upon the experimental objectives. In addition, the device has the ability to create a protein or bivalent cation gradient in the aqueous phase above the lipid bilayer and to elicit a gradient specific response in the SLB...
November 1, 2017: Chemistry and Physics of Lipids
N M Litvinko, L A Skorostetskaya, D O Gerlovsky
Phospholipase A2 (PLA2 IB) activity towards UV-irradiated (λ=180-400nm) phospholipids in comparison to non-irradiated ones was investigated using phosphatidylcholine (PC) liposomes and mixed micelles of phosphatidylcholine and sodium deoxycholate as a membrane model. PLA2 activity, determined by spectral changes of hemoglobin (Hb) under the interaction with fatty acids (product of the phospholipolysis), correlated well with the phospholipid peroxidation degree. The present work is the first study that determines the degree of oxidation of non-fragmented OxPCs, on the base of PLA2 activity...
October 31, 2017: Chemistry and Physics of Lipids
Andrew J Clulow, Malinda Salim, Adrian Hawley, Ben J Boyd
Milk has been recently reported to form complex self-assembled liquid crystalline structures during digestion by lipolytic enzymes. The formation of cubic phases at the endpoint of digestion was of particular interest as this requires a fine balance in self-assembly. This manuscript probes the robustness of the kinetic structural behaviour when milk is subjected to a range of processes that are encountered by milk and/or are relevant to the use of milk in pharmaceutical applications (homogenisation, lyophilisation, freeze-thaw and freeze-drying) using time-resolved small angle X-ray scattering (TR-SAXS)...
October 31, 2017: Chemistry and Physics of Lipids
Mustafa Elsayed, Marwa M Ibrahim, Gregor Cevc
Deformability is not just a fundamentally interesting vesicle characteristic; it is also the key determinant of vesicle ability to cross the skin barrier; i.e. skin penetrability. Development of bilayer vesicles for drug and vaccine delivery across the skin should hence involve optimization of this property, which is controllable by the concentration of bilayer softeners in or near the vesicle bilayers. To this end, we propose a simple method for quantifying the effect of bilayer softeners on deformability of bilayer vesicles...
October 28, 2017: Chemistry and Physics of Lipids
Yu Zheng, Xin Liu, Nataliya M Samoshina, Vyacheslav V Samoshin, Andreas H Franz, Xin Guo
Recently developed lipids with the trans-2-aminocyclohexanol (TACH) moiety represent unique pH-sensitive conformational switches ("flipids") that can trigger the membrane of liposome-based drug delivery systems at lowered pH as seen in many pathological scenarios. A library of flipids with various TACH-based headgroups and hydrocarbon tails were designed, prepared, and characterized to systematically elucidate the relationship between their chemical structures and their ability to form and to trigger liposomes...
October 27, 2017: Chemistry and Physics of Lipids
Erwann Durand, André Delavault, Claire Bourlieu, Jérôme Lecomte, Bruno Baréa, Maria Cruz Figueroa Espinoza, Eric A Decker, Françoise Michel Salaun, Gilles Kergourlay, Pierre Villeneuve
Regardless of the applications: therapeutic vehicle or membrane model to mimic complex biological systems; it is of a great importance to develop simplified, reproducible and rapid model assays allowing for a relevant assessment of the liposomal membrane oxidation and therefore antioxidant activity of selected molecules. Here, we describe a new and high-throughput assay that we called "Vesicle Conjugated Autoxidizable Triene (VesiCAT)". It is based on specific UV absorbance spectral properties of a new phospholipid probe, synthesized with natural conjugated eleostearic acid extracted from Tung oil...
October 20, 2017: Chemistry and Physics of Lipids
Monaj Karar, Suvendu Paul, Arabinda Mallick, Tapas Majumdar
Harmine, an efficient cancer cell photosensitizer (PS), emits intense violet color when it is incorporated in well established self assembly based drug carrier formed by cationic surfactants of identical positive charge of head group but varying chain length, namely, dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB) and cetyltrimethylammonium bromide (CTAB). Micelle entrapped drug emits in the UV region when it interacts with non-toxic β-cyclodextrin (β-CD). Inspired by these unique fluorescence/structural switching properties of the anticancer drug, in the present work we have monitored the interplay of the drug between micelles and non-toxic β-CDs...
October 19, 2017: Chemistry and Physics of Lipids
Hitoshi Matsuki, Kentaro Kato, Hirotsugu Okamoto, Shuntaro Yoshida, Masaki Goto, Nobutake Tamai, Shoji Kaneshina
The variation in phase-transition temperatures of dipalmitoylphosphatidylcholine (DPPC) bilayer membrane by adding two membrane-active ligands, a long-chain fatty acid (palmitic acid (PA)) and an inhalation anesthetic (halothane (HAL)), was investigated by light-transmittance measurements and fluorometry. By assuming the thermodynamic colligative property for the bilayer membrane at low ligand concentrations, the partitioning behavior of these ligands into the DPPC bilayer membrane was considered. It was proved from the differential partition coefficients between two phases that PA has strong affinity with the gel (lamellar gel) phase in a micro-molal concentration range and makes the bilayer membrane more ordered, while HAL has strong affinity with the liquid crystalline phase in a milli-molal concentration range and does the bilayer membrane more disordered...
October 16, 2017: Chemistry and Physics of Lipids
Ji-Yeon Chun, Sang-Gi Min, Yeon-Ji Jo
To encapsulate water soluble collagen peptides, liposomes loaded with peptides were assembled using a combination of thin film hydration and ultrasonication emulsification techniques. The influence of lipid charge, duration and power of ultrasonication, and collagen peptide concentration were evaluated. Layered liposomes loaded with collagen peptides, charged lipids, chitosan (+) or low-methoxyl pectin (-) were produced using the layer-by-layer electrostatic deposition method. For the liposomes loaded with collagen peptides, the most efficient and dependable manufacturing method was variation of the ultrasonication duration, which was capable of producing smaller sizes (through increasing ultrasonication duration) and liposomes loaded with peptides with >60% encapsulation efficiency...
October 12, 2017: Chemistry and Physics of Lipids
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