Phonons reveal coupled cholesterol-lipid dynamics in ternary membranes.

Experimental studies of collective dynamics in lipid bilayers have been challenging due to the energy resolution required to observe these low-energy phonon-like modes. However, inelastic x-ray scattering (IXS) measurements-a technique for probing vibrations in soft and biological materials-are now possible with sub-meV resolution, permitting direct observation of low-energy, phonon-like modes in lipid membranes. Here, IXS measurements with sub-meV energy resolution reveal a low-energy optic-like phonon mode at roughly 3 meV in the liquid-ordered (L) and liquid-disordered phases of a ternary lipid mixture.

Structural and Thermomagnetic Properties of Gallium Nanoferrites and Their Influence on Cells In Vitro.

Magnetite and gallium substituted cuboferrites with a composition of GaFeO (0 ≤ x ≤ 1.4) were fabricated by thermal decomposition from acetylacetonate salts. The effect of Ga cation substitution on the structural and thermomagnetic behavior of 4-12 nm sized core-shell particles was explored by X-ray and neutron diffraction, small angle neutron scattering, transmission electron microscopy, Mössbauer spectroscopy, and calorimetric measurements.

Mechanisms of inward transmembrane proton translocation.

Proton transport is indispensable for cell life. It is believed that molecular mechanisms of proton movement through different types of proton-conducting molecules have general universal features. However, elucidation of such mechanisms is a challenge.

Cholesterol and melatonin regulated membrane fluidity does not affect the membrane breakage triggered by amyloid-beta peptide.

We have studied by means of small angle neutron scattering and diffraction, and molecular dynamics simulations the effect of lipid membrane fluidity on the amyloid-beta peptide interactions with the membrane. These interactions have been discovered previously to trigger the reorganization of model membranes between unilamellar vesicles and planar membranes (bicelle-like structures) during the lipid phase transition. The morphology changes were taking place in rigid membranes prepared of fully saturated lipids and were proposed to play a role in the onset of amyloid related disorders.