Ottosenpreston2933

In particular, the methylamine-substituted polymer forms smaller, monodispersed nanodiscs, while the longer alkyl derivatives form worm-like nanostructures. Thus the introduction of hydrophobicity onto the polar sidechains of amphipathic polymers has profound effects on morphology of native nanodisc, with shorter methyl moieties offering more uniformity and utility for structural biology studies.Polyunsaturated phospholipids in plasma membranes modulate order and dynamics of the lipid bilayer and influence integral membrane protein function. selleck chemical In this study, we investigate the effects of polyunsaturated fatty acid (PUFA) chains in phosphatidylcholine (PC) on osmotic water permeability and packing characteristics, using a droplet interface bilayer (DIB) as a model cell membrane. The lipid bilayer system is composed of mixtures of PC lipids with varying ratio of 1-stearoyl-2-oleoylphosphatidylcholine (SOPC, 18 0-181 PC) to 1-stearoyl-2-docosahexaenoylphosphatidylcholine (SDPC, 180-226 PC). Water permeability coefficients (Pf) were derived from the kinetics of osmotic filtration across the DIB. Confocal Raman microspectroscopy probed the structural and packing properties of the mixtures. The water transport parameters and Raman spectral analyses together indicate that Pf and aggregate ordering of a lipid bilayer are significantly influenced by the progressive addition of PUFA chains to a bilayer. The permeability rates across bilayers of the mixtures are a linear function of SDPC mol%. The mean disorder for the bilayer hydrocarbon region, as determined by Raman disorder parameter from the saturated chain, scales linearly with Pf. The linear trend for Pf versus degree of unsaturation in double-chain PC lipid bilayers is about half the value of that obtained for a single-chain lipid system, with implications for an evolutionary preference for phospholipids during the postulated biotic transition from single-chain lipid protocellular to modern cell membranes. The amassed results highlight the role of PUFA in modifying membrane order as manifest in bulk membrane physical properties, with characteristic differences depending on single-chain or double-chain systems.Raman spectra of hydrated bilayers of 1,2-dilauroyl-sn-glycero-3-phosphocholine (120 PC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (140 PC), and 1,2-distearoyl-sn-glycero-3-phosphocholine (180 PC) were studied in a wide temperature range to characterize the temperature-dependent hydrocarbon chain disorder of the saturated phosphatidylcholines. Temperature dependencies of the Raman line intensities were analyzed for the antisymmetric CH2 stretching and CC stretching vibrations, which are sensitive to the lipid order. It was found that chain disordering processes occur significantly below the gel-fluid transition. The chain conformational order characterized by the CC stretching line intensity can be well described by a model involving the excitation of the ordered conformational state to the kinked and highly disordered, fluid-like state. A relation between the excitation energy to the disordered state and the enthalpy of the gel-fluid transition is discussed, including also data for other phosphatidylcholines studied before. Temperature behavior of the antisymmetric CH2 stretching line indicates that non-conformational degrees of freedom are released above ∼ 200 K. Experimental findings concerning the hydrocarbon chain length dependence of the Raman polarizability of antisymmetric CH2 stretching vibrations and a low-temperature solid-solid phase transition, identified in 120 PC at heating, are also discussed in the work.In the present work, we show how amphipathic diblock copolymers affect the physicochemical properties of the lipid bilayer of DPPC liposome. Diblock copolymers proposed for this study are focused in the difference between PLA and PCL hydrophobic block, because PLA and PCL differ in their glass transition temperature, where a higher ratio of PLA, lowers the flexibility of the diblock copolymer. On the contrary, a greater proportion of PCL makes the diblock copolymer more flexible. This flexibility difference between hydrophobic block would affect the physicochemical properties of lipid bilayer of DPPC. The difference of rigidity or flexibility of hydrophobic block and their interaction with DPPC large unilamellar vesicles (LUVs) was evaluated at low and high copolymers concentration. The copolymer concentrations used were chosen based on their respective cmc. We measure (a) Thermotropic behavior from GP of Laurdan and fluorescence anisotropy of DPH; (b) Relation between wavelength excitation and generalized polower; leading to a decrease in calcein release from DPPC liposomes. Our results clearly show that the greater the stiffness of the hydrophobic block, greater degree of packaging of the lipid bilayer, greater the order of the acyl chains, and greater retention of water and calcein inside the liposome. Therefore, the presence of AB-type diblock copolymers with a more rigid hydrophobic block, stabilizes the lipid bilayer and would allow a more controlled release of water, and encapsulated molecules inside of the DPPC liposome.This study was aimed to investigate the cytotoxic potential of a natural compound, progenin III on a broad range of cancer cell lines, including various sensitive and drug-resistant phenotypes. The cytotoxicity, progenin III-induced autophagic, ferroptotic and necroptotic cell death were evaluated by the resazurin reduction assay (RRA). Spectrophotometric analysis of caspases activity was performed using caspase-Glo assay. Flow cytometry was applied for cell cycle analysis (PI staining), apoptosis (annexin V/PI staining), mitochondrial membrane potential (MMP) (JC-1) and reactive oxygen species (ROS) (H2DCFH-DA). Progenin III and the reference molecule, doxorubicin exerted cytotoxic effects towards the 18 cancer cell lines tested including animal and human cell lines. The IC50 values obtained ranged from 1.59 μM (towards CCRF-CEM leukemia cells) to 31.61 μM (against the BRAF-V600E homozygous mutant SKMel-28 melanoma cells) for progenin III. Normal sensitivity was achieved with CEM/ADR5000 cells and HCT116p53-/- adenocarcinoma cells respectively compared to their sensitive congeners CCRF-CEM cells and HCT116 p53+/+ cells.