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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...
July 13, 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...
July 10, 2018: Chemistry and Physics of Lipids
G Bhattacharya, R P Giri, A Dubey, S Mitra, R Priyadarshni, 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]...
June 23, 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...
May 23, 2018: Chemistry and Physics of Lipids
William M Penny, Christopher P Palmer
Understanding how stereochemistry affects interactions with cell membranes is important for effective drug development. Chirality has been shown to greatly effect pharmaceutical distribution and metabolism within the cell. However it has been thought that interactions with, and passive diffusion through, the membrane are not stereochemically selective. Various studies have produced conflicting results regarding whether interactions with lipid bilayers are or can be stereoselective. In the current work, stereoselective interactions between a pair of atropisomers, R-(+)/(S)-(-) 1,1'-Bi-2-naphthol, and sphingomyelin nanodisc bilayers, are demonstrated...
May 15, 2018: Chemistry and Physics of Lipids
Pavan Walvekar, Ramesh Gannimani, Sanjeev Rambharose, Chunderika Mocktar, Thirumala Govender
Most of the bacteria are on the verge of becoming resistant to available potential antibiotics. Novel approaches to combat these drug resistant bacteria are turning out to be crucial. This study aimed to synthesize novel fatty acid based cationic amphiphiles (FCA) that would serve as nano-drug carrier having intrinsic antibacterial activity. Three fatty acids oleic acid, linoleic acid and linolenic acid based cationic amphiphiles were synthesized and evaluated for antibacterial activity and cytotoxicity. The application in the delivery of vancomycin (VCM) was demonstrated using oleic based cationic amphiphilic (OCA)...
May 3, 2018: Chemistry and Physics of Lipids
Marjut Vähäheikkilä, Tapio Peltomaa, Tomasz Róg, Mario Vazdar, Sanja Pöyry, Ilpo Vattulainen
Cardiolipins have multiple vital functions within biological cell membranes, most notably in the energy metabolism associated with the inner mitochondrial membrane. Considering their essential role, peroxidation of cardiolipins may plausibly have significant effects, as peroxidation is known to alter the functionality of lipid molecules. We used atomistic molecular dynamics simulations to study how peroxidation of cardiolipin affects the properties of the inner mitochondrial membrane. To this end, we explored what happens when varying fractions of fatty acid chains of cardiolipin are replaced by its four different oxidized products in systems modeling the inner mitochondrial membrane...
May 1, 2018: Chemistry and Physics of Lipids
Thomas Schmitt, Rakesh Gupta, Stefan Lange, Stefan Sonnenberger, Bodo Dobner, Thomas Hauß, Beena Rai, Reinhard H H Neubert
For this study mixtures based on the ceramides [NS] (NS = non-hydroxy-sphingosine) and [AP] (AP = α-hydroxy-phytosphingosine) in a 2:1 and 1:2 ratio, together with cholesterol and lignoceric acid, were investigated. These mixtures are modelling the uppermost skin layer, the stratum corneum. Neutron diffraction, utilizing specifically deuterated ceramide molecules, was used to obtain a maximum amount of experimental detail. Highly detailed molecular dynamics simulations were used to generate even more information from the experimental data...
August 2018: Chemistry and Physics of Lipids
Alireza Baghban, Jafar Sasanipour, Mohsen Sarafbidabad, Amin Piri, Razieh Razavi
Micellization phenomenon occurs in natural and technical processes, necessitating the need to develop predictive models capable of predicting self-assembly behavior of surfactants. A least squares support vector machine (LSSVM) based quantitative structure property relationships (QSPR) model is developed in order to predict critical micelle concentration (CMC) for sugar-based surfactants. Model development is based on training and validating a predictive LSSVM strategy using a comprehensive data base consisting of 83 sugar-based surfactants...
August 2018: Chemistry and Physics of Lipids
G K Vladimirov, A S Vikulina, D Volodkin, Yu A Vladimirov
The complex of mitochondrial protein cytochrome c (CytC) with anionic phospholipid cardiolipin (CL) plays a crucial role in the initiation of apoptosis by catalyzing lipid peroxidation in mitochondrial membranes. In our previous papers, we found that CytC and CL mixed in millimolar concentrations form a sediment showing microcrystals composed of nanospheres (Cyt-CL) of 11-12 and 8 nm in diameter. The hypothesis was proposed that Cyt-CL, having hydrophobic shell, may appear inside the membrane lipid bilayer in mitochondria and peroxidase membrane phospholipids so initiating the apoptotic cascade...
August 2018: Chemistry and Physics of Lipids
Hyunbeom Lee, Jong Min Choi, Joo-Youn Cho, Tae-Eun Kim, Hwa Jeong Lee, Byung Hwa Jung
Rosuvastatin is a statin used to treat metabolic syndrome conditions, such as hyperlipidemia. It is relatively safe; however, fatal rhabdomyolysis or skeletal myopathy can sometimes occur. Therefore, to investigate the overall effects of rosuvastatin, including lipid lowering and adverse effects, metabolic profiling was performed using metabolomics and lipidomics after rosuvastatin administration. Specifically, the metabolic profiles between healthy subjects and patients with hyperlipidemia were compared and the metabolic changes related to the mechanism of the drug effect were proposed...
August 2018: Chemistry and Physics of Lipids
Katarzyna Cieślik-Boczula
Resveratrol (Res), a natural polyphenol present in different plants and vegetables, exhibits potential therapeutic activity with cardioprotective, antineurodegenerative, antioxidant, and antitumor action. In this study, the effect of Res on the mutual interactions between positively charged poly-l-lysine (PLL) and negatively charged dipalmitoylphosphatidylcholine/dipalmitoylphosphatidylglycerol (DPPC/DPPG) membranes was studied using Fourier-transform infrared (FTIR) spectroscopy supported by principal component analysis (PCA)...
August 2018: Chemistry and Physics of Lipids
Huina Ruan, Lujing Xu, Shan Hong, Songbai Liu
A general highly efficient solvent-free esterification of phytosterols with edible magnesium oxide and Span-60 emulsifier catalyst system has been developed. The edible emulsifier dramatically promotes the catalyzing activity of the metal oxide in the reaction. The loading of the magnesium oxide is as low as 0.1 wt% to phytosterols and far lower than the known ones. As demonstrated by the results of scanning electro-microscopy (SEM), the synergistic effect of emulsifier and magnesium oxide presumably results from elimination of nano-scale interfacial barrier between phytosterols and fatty acids and facilitation of mass transfer of reaction agents...
July 2018: Chemistry and Physics of Lipids
Zoran Arsov, Emilio J González-Ramírez, Felix M Goñi, Stephanie Tristram-Nagle, John F Nagle
Despite the biological significance of sphingomyelins (SMs), there is far less structural information available for SMs compared to glycerophospholipids. Considerable confusion exists in the literature regarding even the phase behavior of SM bilayers. This work studies both palmitoyl (PSM) and egg sphingomyelin (ESM) in the temperature regime from 3 °C to 55 °C using X-ray diffraction and X-ray diffuse scattering on hydrated, oriented thick bilayer stacks. We observe clear evidence for a ripple phase for ESM in a large temperature range from 3 °C to the main phase transition temperature (TM ) of ∼38 °C...
July 2018: Chemistry and Physics of Lipids
Daniel J Mayo, Indra D Sahu, Gary A Lorigan
Aligned CW-EPR membrane protein samples provide additional topology interactions that are absent from conventional randomly dispersed samples. These samples are aptly suited to studying antimicrobial peptides because of their dynamic peripheral topology. In this study, four consecutive substitutions of the model antimicrobial peptide magainin 2 were synthesized and labeled with the rigid TOAC spin label. The results revealed the helical tilts to be 66° ± 5°, 76° ± 5°, 70° ± 5°, and 72° ± 5° for the TOAC substitutions H7, S8, A9, and K10 respectively...
July 2018: Chemistry and Physics of Lipids
Ezequiel N Frigini, J J López Cascales, Rodolfo D Porasso
Extensive molecular dynamics simulations have been performed to study the effect of glyphosate (in their neutral and charged forms, GLYP and GLYP2- , respectively) on fully hydrated DiPalmitoylPhosphatidylCholine (DPPC) lipid bilayer. First, we calculated the free energy profile (using the Umbrella Sampling technique) for both states of charge of glyphosate. The minimum value for the free energy for GLYP is ∼-60 kJ mol-1 located at z = ±1.7 nm (from the lipid bilayer center), and there is almost no maximum at the center of the lipid bilayer...
July 2018: Chemistry and Physics of Lipids
K Talló, V Moner, M De Cabo, M Cócera, O López
Phospholipids and fatty acids are the main building blocks of biological membranes. Oleic acid is a monounsaturated omega-9 fatty acid commonly found in many natural sources. Its characteristic kinked structure grants this molecule with a great number of biological properties. To better understand the role that this kind of fatty acids play into phospholipid membranes, nanostructured systems formed with hydrogenated soy phosphatidylcholine and oleic acid were studied in this work by means of cryo-electron microscopy, dynamic light scattering and differential scanning calorimetry...
July 2018: Chemistry and Physics of Lipids
Katarzyna Dopierała, Marta Skrzypiec
The aim of the present study was to investigate the interfacial behaviour of model biomembranes in the presence of β-carotene (βC). The Langmuir monolayer technique was used to form the mixed lipid film at the air/water interface. Using the surface pressure-area isotherms, the surface potential-area curves and the Brewster angle microscopy the nature of interactions between carotenoid and lipid components of the monolayers was investigated. The results were obtained for complex models of the lipid bilayer composed of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and cholesterol (CHOL)...
July 2018: Chemistry and Physics of Lipids
Tamara Lützenburg, Ines Neundorf, Matthias Scholz
Herein, we report the synthesis and characterization of direct carborane-peptide conjugates. Carboranes are non-natural and extremely hydrophobic compounds and turned out to be suitable pharmacophores for diverse biological applications. In this work, we established an efficient procedure for the coupling of carboranes to peptides on solid support. We identified the coupling of carborane-1-carboxylic acids to amino groups to be superior to those with hydroxy- or sulfhydryl-groups. The carborane-peptide conjugates showed remarkably prolonged, and carborane isomer dependent chromatographic retention times...
July 2018: Chemistry and Physics of Lipids
Sarmistha Saha, Ramtej J Verma
Eugenol and its related compounds are major active constituents of essential oils and have been extensively used as food flavoring agents with significant lipid peroxidation inhibition activity, highlighting the importance of understanding detailed molecular mechanisms behind their interactions with lipid bilayer. For this, we studied antioxidant activity of essential oils rich extract of Cinnamomum tamala leaves and molecular dynamics simulations of eugenol, isoeugenol, methyleugenol, acetyleugenol and eugenol oxide in POPC and PLPC lipid bilayers...
July 2018: Chemistry and Physics of Lipids
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