Planar Bilayer Measurements of Alamethicin and Gramicidin Reconstituted in Biomimetic Block Copolymers

This work explores methods for forming and characterizing biomimetic planar membranes composed of amphiphilic block copolymers. The membranes are diblocks and triblocks with hydrophilic blocks of poly­(2-methyl-2-oxazoline) (PMOXA) and hydrophobic blocks of poly­(dimethylsiloxane) (PDMS). Experiments with the lipid diphytanoyl phosphocholine (DPhPC) serve as a basis for comparison with the polymeric membranes. Phase-contrast microscopy is used to study how membranes evolve over time after their formation. Capacitance measurements as a function of the thinned membrane area (prepared from two separate solvent systems) are performed to clarify the importance of the Plateau–Gibbs border in electrical measurements. Finally, functional reconstitution of the two ion channels, alamethicin and gramicidin, is investigated. Imaging in transmitted phase-contrast mode provides visualization of thinned regions that contain monolayers or bilayers (in the case of diblock copolymer). The specific capacitance measurements yield 0.28 μF/cm² with a corresponding thickness of 8.5 nm for PMOXA₆-PDMS₃₅-PMOXA₆ (blocks of 6 PMOXA and 35 PDMS repeat units) formed from a solution of ethanol–decane, 0.55 μF/cm² and 4.4 nm in chloroform–toluene, and 0.46 μF/cm² and 5.4 nm for the diblock PMOXA₆-PDMS₁₇ in ethanol–decane. Alamethicin reconstitution in the block copolymers shows slower channel-forming kinetics with somewhat higher conductance values than found in DPhPC. Gramicidin in the block copolymer shows a slightly voltage-dependent conductance as a function of time, with little stochastic conductance state switching, in contrast to reconstitution in DPhPC where gramicidin switches states at ∼3 Hz

Final Potomac Matrices

Methylation susceptible (MS) and unmethylated (UM) matrices from six sampling locations in the Potomac River

Patuxent MSAP Matrices

Methylation susceptible (MS) and unmethylated (UM) matrices from five sampling locations in the Patuxent River

Interspecific MSAP Matrices

Methylation susceptible (MS) and unmethylated (UM) matrices for eight species pairs used in the interspecific analyses

Reviewing the environmental implications of increased consumption and trade of biofuels for transportation in Sweden

<p>Sweden, a European leader in the consumption of biofuels, has surpassed targets set by the EU and is one of a few countries that has increased consumption of biofuels in recent years. Nonetheless, a large share of biofuels, and raw materials used to produce the fuels, are imported from regions outside Sweden. This paper reviews the environmental implications of consumption of biofuels in Sweden 2000–2014 to identify and provide a comprehensive assessment of the environmental impacts that imports of fuels have both in Sweden and abroad using life cycle assessment (LCA). The results suggest that while greenhouse gas emissions may have been reduced in Sweden by the use of biofuels, the origin of the emissions has shifted from Sweden to Europe and other countries abroad, due in part to an increased use of biofuels and raw materials from abroad. This has important implications for local impacts, as this may increase acidification and eutrophication potential and ecotoxicity created abroad. Thus, although policy has been designed to promote sustainable transportation fuels, in addition to the generation goals set by the Swedish Parliament, the implications on regions exporting fuels and raw materials for Swedish consumption should be reviewed and followed in further detail in order to avoid problem shifting.</p

GENELAND coordinate input file for modern samples

GENELAND coordinate input file for modern sample

GENEPOP input file with modern populations data

GENEPOP input file with modern populations dat

GENELAND sample ID input file for modern samples

GENELAND sample ID input file for modern sample

Model of mechanism involved in HBD-2 secretion in gingival epithelial cells.

<p>Triggering TLRs by respective ligand stimulates the cells to induce HBD-2. This induction can be ablated by a pharmacological inhibitor against Sphk-1, and inhibition of GSK3 by SB216763 or siGSK3-β in the absence of Sphk-1 inhibition can augment HBD-2 secretion. Inhibition of PI3K by either wortmannin or LY294002 abrogated HBD-2 in gingival epithelial cells. PI3K activated Akt, the phosphorylation of Akt inhibited GSK3 in turn activating ERK 1/2. ERK 1/2 activates Sphk-1 by phosphorylation at Ser225 and increase NF-kB activity. This show PI3K-Akt-GSK3-ERK1/2-Sphk-1 mediates HBD-2 synthesis in gingival epithelial cells.</p

Dose dependent inhibition of HBD-2 induction in HGECs upon Sphk-1 inhibition.

<p>Keratinocytes were pretreated with Sphk-1 inhibitor at various concentrations ranging from 0.1 µM to 5.0 µM for 2 h prior to challenging the cells with FSL-1 ligand (1 µg/ml) for 24. Supernatant was subjected to human HBD-2 ELISA. Sphk-1 inhibitor dose dependently inhibited the induction of HBD-2 (<b>A</b>). In another set of experiment, total protein was collected after 60 min of challenge as mentioned above. Immunoblot was performed with ser225 phospho specific Sphk-1 antibody and β-actin as loading control. The level of phosphorylation of Sphk-1 at ser225 was dose dependently down regulated upon Sphk-1 inhibitor treatment (<b>B</b>). Results are mean ± SEM and are representative of three independent experiments.</p