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membran lipids

Clizia Guccione, Maria Camilla Bergonzi, Khaled M Awada, Vieri Piazzini, Anna Rita Bilia
The aim of this study was the development and characterization of lipid nanocarriers using food grade components for oral delivery of Serenoa repens CO2 extract, namely microemulsions (MEs) and self-microemulsifying drug delivery systems (SMEDDSs) to improve the oral absorption. A commercial blend (CB) containing 320 of S. repens CO2 extract plus the aqueous soluble extracts of nettle root and pineapple stem was formulated in two MEs and two SMEDDSs. The optimized ME loaded with the CB (CBM2) had a very low content of water (only 17...
March 15, 2018: Planta Medica
Emily Wonder, Lorena Simón-Gracia, Pablo Scodeller, Ramsey N Majzoub, Venkata Ramana Kotamraju, Kai K Ewert, Tambet Teesalu, Cyrus R Safinya
Cationic liposome-nucleic acid (CL-NA) complexes, which form spontaneously, are a highly modular gene delivery system. These complexes can be sterically stabilized via PEGylation [PEG: poly (ethylene glycol)] into nanoparticles (NPs) and targeted to specific tissues and cell types via the conjugation of an affinity ligand. However, there are currently no guidelines on how to effectively navigate the large space of compositional parameters that modulate the specific and nonspecific binding interactions of peptide-targeted NPs with cells...
March 2, 2018: Biomaterials
Alexander Gluschko, Marc Herb, Katja Wiegmann, Oleg Krut, Wolfram F Neiss, Olaf Utermöhlen, Martin Krönke, Michael Schramm
The intracellular pathogen Listeria monocytogenes (L.m.) is targeted by the autophagic machinery, but the molecular mechanisms involved and consequences for anti-listerial immunity remain enigmatic. Here, we demonstrate that L.m. infection of macrophages in vivo exclusively evokes LC3-associated phagocytosis (LAP), but not canonical autophagy, and that targeting of L.m. by LAP is required for anti-listerial immunity. The pathway leading to LAP induction in response to L.m. infection emanates from the β2 integrin Mac-1 (CR3, integrin αM β2 ), a receptor recognizing diverse microbial ligands...
March 14, 2018: Cell Host & Microbe
Marta Martínez-Calle, Bárbara Olmeda, Paul Dietl, Manfred Frick, Jesús Pérez-Gil
The release of pulmonary surfactant by alveolar type II (ATII) cells is essential for lowering surface tension at the respiratory air-liquid interface, stabilizing the lungs against physical forces tending to alveolar collapse. Hydrophobic surfactant protein (SP)-B ensures the proper packing of newly synthesized surfactant particles, promotes the formation of the surface active film at the alveolar air-liquid interface and maintains its proper structure along the respiratory dynamics. We report that membrane-associated SP-B efficiently induces secretion of pulmonary surfactant by ATII cells, at the same level as potent secretagogues such as ATP...
March 15, 2018: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Sreetama Pal, Nirnay Samanta, Debasish Das Mahanta, Rajib Kumar Mitra, Amitabha Chattopadhyay
Biological membranes are highly organized supramolecular assemblies of lipids and proteins. The membrane interface separates the outer (bulk) aqueous phase from the hydrophobic membrane interior. In this work, we have explored the microstructure and collective dynamics of the membrane interfacial hydration shell in zwitterionic and negatively charged phospholipid membrane bilayers using terahertz time-domain spectroscopy. We show here that the relaxation time constants of water hydrogen bond network exhibit a unique "rise and dip" pattern with increasing lipid concentration...
March 15, 2018: Journal of Physical Chemistry. B
Stephen E McGowan, Diann M McCoy
Secondary alveolar septa are mostly generated after birth in humans and in mice this is completely accomplished postnatally, when mechanical stresses vary as airspace pressure oscillates. Alveolar mesenchymal cells deposit elastic fibers which limit cellular strain, but while the elastic fiber network is incomplete, this function is also served by the intracellular cytoskeleton. Intermediate filament proteins support deformation during cellular division and migration, which occur during septal elongation. Because platelet-derived growth factor-alpha (PDGFRα) signaling is essential for alveolar septation, we hypothesized that neuropilin-1 (NRP1) may link PDGFRα to cytoskeletal deformation...
March 15, 2018: American Journal of Physiology. Lung Cellular and Molecular Physiology
Chiho Watanabe, Miho Yanagisawa
Micrometric membrane confinements and macromolecular crowding of cytoplasm are key factors that regulate molecular diffusion in live cells. Previous studies have shown that macromolecular crowding delays molecular diffusion. However, the effect of cell-size confinement on diffusion in the crowding environment is yet to be elucidated. Using fluorescence correlation spectroscopy (FCS), we analyzed protein diffusion in microdroplets containing polymer solution covered with lipid membranes that mimic cells. As a result, we found that a synergistic condition of crowding and micrometric confinement results in accelerated protein diffusion on a sub-millisecond time scale...
March 15, 2018: Physical Chemistry Chemical Physics: PCCP
Wei Sun, Ju-Dong Luo, Hua Jiang, Dayue Darrel Duan
Tumor cells produce and secrete more nucleic acids, proteins and lipids than normal cells. These molecules are transported in the blood or around the cells in membrane-encapsulated exosomes. Tumor-derived or tumor-associated exosomes (usually 30-100 nm in diameter) contain abundant biological contents resembling those of the parent cells along with signaling messengers for intercellular communication involved in the pathogenesis, development, progression, and metastasis of cancer. As these exosomes can be detected and isolated from various body fluids, they have become attractive new biomarkers for the diagnosis and prognosis of cancer...
March 15, 2018: Acta Pharmacologica Sinica
Hui Ye
Antimicrobial peptides are derived from the viral fusion domain of influenza virus hemagglutinin based on rational analysis of the intermolecular interaction between peptides and bacterial outer membrane. It is revealed that the isolated viral fusion domain is a negatively charged peptide HAfp1-23 that cannot effectively interact with the anionic membrane. Conversion of the native HAfp1-23 to a positively charged peptide HAfp1-23 _KK by E11K/D19K mutation can promote the peptide-membrane interaction substantially; this confers to the peptide a moderate antibacterial potency against antibiotic-resistant bacterial strains...
March 2018: Journal of Peptide Science: An Official Publication of the European Peptide Society
Kotoku Kawaguchi, Ryo Hatano, Mitsunobu Matsubara, Shinji Asano
Moesin is expressed in several types of cells including epithelial and endothelial cells. Several groups reported that moesin plays important roles in the regulation of the cellular motility, and the process of internalization of membrane proteins. However, the physiological roles of moesin in the kidney still remain unclear. Herein, we examined the physiological function of moesin in the kidney using moesin knockout (Msn-/y ) mice. There was no obvious abnormality in the renal morphology of Msn-/y mice. However, we found that Msn-/y mice exhibited mild hyperchloremia, and reduced glomerular filtration rate compared to wild type (WT) mice...
March 15, 2018: Pflügers Archiv: European Journal of Physiology
Sascha Suffner, Nadine Gerstenberg, Maria Patra, Paula Ruibal, Ahmed Orabi, Michael Schindler, Volker Bruss
During hepatitis B virus infections subviral particles (SVP) consisting only of viral envelope proteins and lipids are secreted. Heterologous expression of the small envelope protein S in mammalian cells is sufficient for SVP generation. S is synthesized as a transmembrane protein with N-terminal (TM1), central (TM2), and C-terminal (HCR) transmembrane domains. The loops between TM1 and TM2 (CL) and between TM2 and HCR (LL) are located in the cytosol and in the ER lumen, respectively. To define domains of S mediating oligomerization during SVP morphogenesis S mutants were characterized by expression in transiently transfected cells...
March 14, 2018: Journal of Virology
Ernst R Werner, Markus A Keller, Sabrina Sailer, Daniele Seppi, Georg Golderer, Gabriele Werner-Felmayer, Raphael A Zoeller, Katrin Watschinger
Plasmanylethanolamine desaturase (E.C. introduces the 1-prime double bond into plasmalogens, one of the most abundant phospholipids in the human body. This labile membrane enzyme has not been purified and its coding sequence is unknown. Previous assays for this enzyme used radiolabeled substrates followed by multistep processing. We describe here a straight-forward method for the quantification of plasmanylethanolamine desaturase in enzyme incubation mixtures using pyrene-labeled substrates and reversed phase high performance liquid chromatography (HPLC) with fluorescence detection...
March 14, 2018: Journal of Lipid Research
Tamako Nishimura, Nobuhiro Morone, Shiro Suetsugu
Lipid membranes are structural components of cell surfaces and intracellular organelles. Alterations in lipid membrane shape are accompanied by numerous cellular functions, including endocytosis, intracellular transport, and cell migration. Proteins containing Bin-Amphiphysin-Rvs (BAR) domains (BAR proteins) are unique, because their structures correspond to the membrane curvature, that is, the shape of the lipid membrane. BAR proteins present at high concentration determine the shape of the membrane, because BAR domain oligomers function as scaffolds that mould the membrane...
March 14, 2018: Biochemical Society Transactions
Ishan Ghai, Harsha Bajaj, Jayesh Arun Bafna, Hussein Ali El Damrany Hussein, Mathias Winterhalter, Richard Wagner
The outer cell wall of the Gram-negative bacteria is a crucial barrier for antibiotics to reach their target. Here we show that the chemical stability of the widely used antibiotic ampicillin is a major factor in the permeation across OmpF to reach the target in the periplasm. Using planar lipid bilayer we investigated the interactions and permeation of OmpF with ampicillin, its basic pH induced primary degradation product (penicilloic acid), and the chemically more stable benzylpenicillin. We found that the solute induced ion current fluctuation is 10 times higher with penicilloic-acid than with ampicillin...
March 14, 2018: Journal of Biological Chemistry
Asghar M Razavi, George Khelashvili, Harel Weinstein
BACKGROUND: Much of the structure-based mechanistic understandings of the function of SLC6A neurotransmitter transporters emerged from the study of their bacterial LeuT-fold homologs. It has become evident, however, that structural differences such as the long N- and C-termini of the eukaryotic neurotransmitter transporters are involved in an expanded set of functional properties to the eukaryotic transporters. These functional properties are not shared by the bacterial homologs, which lack the structural elements that appeared later in evolution...
March 14, 2018: BMC Biology
Tong Chen, Dongchao Ji, Shiping Tian
BACKGROUND: The assembly of protein complexes and compositional lipid patterning act together to endow cells with the plasticity required to maintain compositional heterogeneity with respect to individual proteins. Hence, the applications for imaging protein localization and dynamics require high accuracy, particularly at high spatio-temporal level. RESULTS: We provided experimental data for the applications of Variable-Angle Epifluorescence Microscopy (VAEM) in dissecting protein dynamics in plant cells...
March 14, 2018: BMC Plant Biology
Daniel Alejandro Peñalva, Silvia Antollini, Ernesto Ambroggio, Marta I Aveldaño, Maria Laura Fanani
In rat sperm head, sphingomyelin (SM) species that contain very long chain PUFA (V-SM) become ceramides (V-Cer) after inducing in vitro the acrosomal reaction. The reason for such a specific location of this conversion, catalysed by a sphingomyelinase (SMase), has received little investigation so far. Here, the effects of SMase were compared in unilamellar vesicles (LUVs, GUVs) containing phosphatidylcholine and either V-SM or a palmitate-rich SM (P-SM). In uniformly sized LUVs at 37 °C, more V-Cer was generated, and more rapidly, than P-Cer...
March 15, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Jiakai Lu, Diego Martín Martín Campana, Carlos M Corvalan
The contraction of surfactant-laden pores at the microscale has implications for natural and technological processes ranging from the collapse of channels in lipid membranes to the stability of foams in the food processing industry. Despite its prevalence, our understanding of the mechanisms of pore contraction in the presence of surfactants remains unclear. These mechanisms are challenging to study experimentally given the small length scale near the singularity and simulations capable of accurately characterizing the pore dynamics may help enhance our understanding of the process...
March 14, 2018: Langmuir: the ACS Journal of Surfaces and Colloids
Anthony Watts
Saturation transfer difference (STD) NMR constitutes one of the most popular ligand-based NMR techniques for the study of protein-ligand interactions. This is due to its robustness and the fact that it is focused on the signals of the ligand, without any need for NMR information of the macromolecular target. This technique is most commonly applied to systems involving different types of ligands (e.g. small organic molecules, carbohydrates, or lipids) and a protein as the target, where the latter is selectively saturated...
March 14, 2018: Chembiochem: a European Journal of Chemical Biology
Ankush Checkervarty, Marco Werner, Jens-Uwe Sommer
We study pore formation in models of lipid bilayer membranes interacting with amphiphilic copolymers mimicking anti-microbial peptides using Monte Carlo simulations and we rationalize our results by a simple brush-model for the fluid membrane. In our study a weak tension on the membrane is required to observe pore-formation induced by the adsorption of flexible amphiphilic copolymers. The copolymers enhance the pore stability by decreasing the line tension due to weak adsorption along the rim of the pore. Pore formation is enhanced with increasing length of copolymers or stronger stretching of the membrane...
March 14, 2018: Soft Matter
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