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Chemistry and Physics of Lipids

S Thirupathi Reddy, Musti J Swamy
N-Acylglycines (NAGs), the endogenous single-tailed lipids present in rat brain and other mammalian tissues, play significant roles in cell physiology and exhibit interesting pharmacological properties. In the present study, a homologous series of N-acylglycine alkyl esters (NAGEs) with matched chains were synthesized and characterized. Results of differential scanning calorimetric studies revealed that all NAGEs exhibit a single sharp phase transition and that the transition enthalpy and entropy show a linear dependence on the N-acyl and ester alkyl chain length...
September 7, 2017: Chemistry and Physics of Lipids
Hiroshi Takahashi, Kotaro Jojiki
Heavy water (D2O) affects various functions of cells and living things. In order to gain fundamental insight into the molecular mechanism on biological effects of heavy water (D2O), D2O-effects on fully hydrated monoolein (MO) systems were investigated from the structural viewpoints. At room temperature, the MO fully hydrated by pure light water (H2O) forms a bicontinuous cubic (Pn3m) phase, and then, the Pn3m cubic phase transforms into an inverted hexagonal (HII) phase at about 90°C. Temperature-scan X-ray diffraction measurements showed that substitution of D2O for H2O lowers the Pn3m-to-HII phase transition temperature and reduces the lattice constants of both phases...
September 6, 2017: Chemistry and Physics of Lipids
Ina Hvidsten, Svein Are Mjøs, Bjarte Holmelid, Gunhild Bødtker, Tanja Barth
Dietzia sp. A14101 belonging to the genus Dietzia (Gram-positive bacteria, Actinomycetes, high G+C content of DNA) was isolated from an oil reservoir model column inoculated with oil-field bacteria (Bødtker et al., 2009). Low interfacial tension (IFT) values were obtained by studying intact strain cells grown on water-immiscible hydrocarbons (HC) (Kowalewski et al. (2004), Kowalewski et al. (2005). Further investigations showed that the adaptation mechanism of Dietzia sp. A14101 to toxic water-immiscible HC involved changes both on the level of fatty acids content and in the physical properties of the cellular surface (development of the negative cellular surface charge and an increased in hydrophobicity) (Hvidsten et al...
August 31, 2017: Chemistry and Physics of Lipids
Ina Hvidsten, Svein Are Mjøs, Gunhild Bødtker, Tanja Barth
Dietzia sp. A14101 isolated from an oil reservoir model column was found to induce a strong decrease of the interfacial tension (IFT) in hydrocarbon-water mixtures in the presence of the intact bacterial cells (Kowalewski et al., 2005). The strain was shown to be able to degrade a wide range of hydrocarbon substrates (Bødtker et al., 2009). Further studies showed that the surface-active compounds tentatively identified as glycolipids were produced by Dietzia sp. A14101 on non- and water-immiscible -hydrocarbon substrates, Part I (Hvidsten et al...
August 31, 2017: Chemistry and Physics of Lipids
Dhilan C Tribovane, Matthias S Scholz
Lipids are defined as apolar molecules comprising as major classes fatty acids and fatty acid esters of normally natural origin. Non-natural components, such as dicarba-closo-dodecaboranes (in short carboranes) can also form acids and esters, which reveal lipid-like properties. Carboranes are synthetic boron clusters featuring ten BH and two CH vertices, organized in icosahedral shape. The highly hydrophobic clusters are organic-inorganic hybrid constructs and can be modified at both the cluster boron and the cluster carbon atoms via adjusted organic reactions...
August 30, 2017: Chemistry and Physics of Lipids
Sri Vishnu Kiran Rompicharla, Himanshu Bhatt, Aashma Shah, Neeraja Komanduri, Dhanya Vijayasarathy, Balaram Ghosh, Swati Biswas
The aim of the present research was to develop a novel, biocompatible, amenable to industrial scale up and affordable solid lipid nanoparticles (SLN) preparation of curcumin and evaluate the therapeutic efficacy in vitro using cancer cells. We have incorporated cholesterol as the lipid to prepare SLN along with the Poloxamer-188 as stabilizer. High shear homogenization was used to prepare the SLN and formulation was optimized using Quality by Design The optimized Chol CUR SLN exhibited a narrow size distribution with a particle size of 166...
August 23, 2017: Chemistry and Physics of Lipids
Nathalie Willems, Mickäel Lelimousin, Jakob Skjold-Jorgensen, Allan Svendsen, Mark S P Sansom
Lipases naturally function at the interface formed between amphiphilic molecules and the aqueous environment. Thermomyces lanuginosus lipase (TLL) is a well-characterised lipase, known to exhibit interfacial activation during which a lid region covering the active site becomes displaced upon interaction with an interface. In this study, we investigate the effect the amino acid sequence of the lid region on interfacial binding and lid dynamics of TLL. Three TLL variants were investigated, a wild-type variant, a variant containing an esterase lid region (Esterase), and a Hybrid variant, containing both wild-type lid residues and esterase lid residues...
August 14, 2017: Chemistry and Physics of Lipids
Ellen M Adams, Alex M Champagne, Joseph B Williams, Heather C Allen
The outermost layer of skin, the stratum corneum (SC), contains a complex mixture of lipids, which controls the rate of cutaneous water loss (CWL) in reptiles, mammals, and birds. However, the molecular structure of SC lipids and how molecular configurations influence CWL is poorly understood. Here, the organization and structure of SC lipids extracted from birds were investigated by means of Langmuir films. Properties of lipids from the SC of arid and semi-arid adapted larks, known to have a low CWL, were compared with lipids extracted from the SC of mesic lark species with higher CWL to gain insight into how structure impacts CWL...
August 12, 2017: Chemistry and Physics of Lipids
Charbel Massaad, Luigi Iuliano, Gérard Lizard
No abstract text is available yet for this article.
August 11, 2017: Chemistry and Physics of Lipids
Charbel Massaad, Luigi Iuliano, Gérard Lizard
No abstract text is available yet for this article.
August 8, 2017: Chemistry and Physics of Lipids
Emmanuel Noguer, Régis Soules, Claude Netter, Citra Nagarathinam, Julie Leignadier, Emilie Huc-Claustre, Nizar Serhan, Arnaud Rives, Philippe de Medina, Sandrine Silvente-Poirot, Marc Poirot
Dendrogenin A (DDA) was recently identified as a mammalian cholesterol metabolite that displays tumor suppressor and neurostimulating properties at low doses. In breast tumors, DDA levels were found to be decreased compared to normal tissues, evidencing a metabolic deregulation of DDA production in cancers. DDA is an amino-oxysterol that contains three protonatable nitrogen atoms. This makes it physico-chemically different from other oxysterols and it therefore requires specific analytical methods We have previously used a two-step method for the quantification of DDA in biological samples: 1) DDA purification from a Bligh and Dyer extract by RP-HPLC using a 250×4...
July 3, 2017: Chemistry and Physics of Lipids
Débora Levy, Thatiana Correa de Melo, Jorge L M Ruiz, Sérgio P Bydlowski
Oxysterols are oxidized products of cholesterol that play several roles in various pathophysiological processes, including the control of lipid metabolism, immunological processes, and cytotoxicity. Mesenchymal stem cells are multipotent cells with properties of self-renewal and the ability to differentiate into other cell types, including osteoblasts and adipocytes. Here, we review the literature regarding the effects of oxysterols on mesenchymal stem cell differentiation and the main signaling pathways involved in this process...
June 29, 2017: Chemistry and Physics of Lipids
Lívia Rosa-Fernandes, Luciana M F Maselli, Nair Y Maeda, Giuseppe Palmisano G, Sergio P Bydlowski
Oxysterols are cholesterol oxidation products formed through enzymatic or autoxidation mechanisms. 7-ketocholeterol (7KC) is one of most abundant oxysterols found in atherosclerotic lesions. Its role in atherosclerosis pathogenesis has been broadly studied in a variety of models. The arterial microenvironment is a multicellular dynamic compartment that, among other systemic factors, is continuously stimulated by 7KC. Endothelial cells have a key role on that environment, being in intimate contact with both the blood stream and the vessel wall, the site of disease origin...
June 26, 2017: Chemistry and Physics of Lipids
Elodie Olivier, Mélody Dutot, Anne Regazzetti, Olivier Laprévote, Patrice Rat
Degenerative diseases are characterized by both cell death and inflammation, which involve different pathways such as apoptosis and pyroptosis. Oxysterols, oxidized derivatives of cholesterol, are known to act as key actors in degenerative disorders such as skin photoaging. We hypothesize that oxysterols could be implicated in either apoptosis or pyroptosis, or both. The aim of our study was first to quantify oxysterol levels in keratinocytes as a function of aging and UV irradiation. Second, we evaluated the effects of 25-OH oxysterol on apoptosis and pyroptosis hallmarks in keratinocytes...
June 23, 2017: Chemistry and Physics of Lipids
Dayane S Alvares, Natalia Wilke, João Ruggiero Neto, Maria Laura Fanani
Polybia-MP1 or simply MP1 (IDWKKLLDAAKQIL-NH2) is a peptide with broad-spectrum bactericidal activity and a strong inhibitory effect against cancer cells. The aim of this work was to evaluate the effect of biophysical properties such as membrane texture and film thickness on MP1 interaction with neutral and anionic lipid membranes. For this purpose, we first explored the peptide's surface behavior. MP1 showed high surface activity, adsorbing onto bare air/aqueous interfaces up to higher surface pressures than the collapse pressure of MP1 Langmuir films...
October 2017: Chemistry and Physics of Lipids
Joshy K S, Snigdha S, Nandakumar Kalarikkal, Laly A Pothen, Sabu Thomas
The major challenges to clinical application of zidovudine are its moderate aqueous solubility and relative short half-life and serious side effects due to frequent administrations. We investigated the preparation of zidovudine-loaded nanoparticles based on lipids which were further modified with the polymer gelatin. Formulation and stability of the modified nanoparticles were analysed from the physico-chemical characterizations. The interactions of nanoparticles with blood components were tested by haemolysis and aggregation studies...
October 2017: Chemistry and Physics of Lipids
Tien T T Do, Uyen P N Dao, Huong T Bui, Trang T Nguyen
The interaction between a drug molecule and lipid bilayers is highly important regarding the pharmaceutical activity of the drug. In this study, the interaction of fluoxetine, a well-known selective serotonin reuptake inhibitor antidepressant and lipid bilayers composed of 1,2-dipalmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG) and 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) was studied from the aspect of electrostatics using second derivative spectrophotometry and Fourier transform infrared spectroscopy (FTIR) in order to provide insights into the drug behavior...
October 2017: Chemistry and Physics of Lipids
Sławomira Drzymała-Czyż, Sophie Janich, Mario Klingler, Johann Demmelmair, Jarosław Walkowiak, Berthold Koletzko
BACKGROUND: Whole blood total fatty acid analysis in capillary blood has recently been proposed for fatty acid status determination, but the accuracy of this method is affected by the fast turnover of triaclyglyceride (TAG) fatty acids, the individual hematocrit and postprandial state. METHOD: An established method for the glycerophospholipid (GPL) analysis in plasma was adapted for the analysis of whole blood GPL and tested in a fat challenge test. Blood samples were collected from nine participants after receiving a standardised breakfast containing 42g of sunflower oil...
October 2017: Chemistry and Physics of Lipids
Reg P Rehal, Helene Marbach, Alasdair T M Hubbard, Anam A Sacranie, Federica Sebastiani, Giovanna Fragneto, Richard D Harvey
The increased biosynthesis of lysyl-phosphatidylglycerol in Staphylococcus aureus when cultured under conditions of mild acidity and the resultant increased proportion of this lipid in the plasma membrane of the bacterium, alters the physico-chemical properties of lipid bilayers in a manner which is itself dependent upon environmental pH. Clinically relevant strains of S. aureus, both methicillin susceptible and resistant, all exhibited increased lysyl-phosphatidylglycerol biosynthesis in response to mild environmental acidity, albeit to differing degrees, from ∼30% to ∼55% total phospholipid...
August 2017: Chemistry and Physics of Lipids
Meddy El Alaoui, Laurent Soulère, Alexandre Noiriel, Yves Queneau, Abdelkarim Abousalham
Lipases are essentially described as sn-1 and sn-3 regio-selective. Actually few methods are available to measure this lipase regio-selectivity, moreover they require chiral chromatography analysis or specific derivations which are discontinuous and time consuming. In this study we describe a new, convenient, sensitive and continuous spectrophotometric method to screen lipases regio-selectivity using synthetic triglycerides (TG) containing α-eleostearic acid (9Z, 11E, 13E-octadecatrienoic acid) either at the sn-1 position [1-α-eleostearoyl-2,3-octadecyl-sn-glycerol (sn-EOO)] or at the sn-3 position [1,2-octadecyl-3-α-eleostearoyl-sn-glycerol (sn-OOE)] and coated onto the wells of microtiter plates...
August 2017: Chemistry and Physics of Lipids
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