Cellular processes depend on controlled transport of material across the cell membrane, typically by the formation of ion specific channels and pores. The major difficulty in studying trans-membrane pores experimentally is that they are usually below the theoretical resolution of light microscope. Thus, pores have been produced and investigated extensively in membranes using indirect techniques...

Cholesterol is distributed unevenly between different cellular membrane compartments, and the cholesterol content increases from the inner bilayers toward the plasma membrane. It has been suggested that this cholesterol gradient is important in the sorting of transmembrane proteins. Cholesterol has also been to shown play an important role in lateral organization of eukaryotic cell membranes. I...

The spontaneous colloidal nanostructures formed in water by the zwitterionic phospholipid DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) with the cationic detergent DTAC (n-dodecyltrimethylammonium chloride) were investigated at a fixed DMPC concentration and variable detergent:lipid total molar ratios (D:L). Apparent (neutral-sphere-equivalent) hydrodynamic diameters (Φ(e)) of liposomes an...

Several complementary physical techniques have been used to characterize the aggregate structures formed in solutions containing dimyristoylphosphatidylcholine (DMPC)/dihexanoylphosphatidylcholine (DHPC) at ratios of < or =0.5 and to establish their morphology and lipid organization as that of bicelles. (31)P NMR studies showed that the DMPC and DHPC components were highly segregated over a wid...

Positively charged lipid bilayer systems are a promising class of nonviral vectors for safe and efficient gene and drug delivery. Detailed understanding of these systems is therefore not only of fundamental but also of practical biomedical interest. Here, we study bilayers comprising a binary mixture of cationic dimyristoyltrimethylammoniumpropane (DMTAP) and zwitterionic (neutral) dimyristoylp...

S-nitroso-N-acetylpenicillamine (SNAP) is a pharmacological agent with diverse biological effects that are mainly attributable to its favorable characteristics as a nitric oxide (NO)-evolving agent. It is found that SNAP incorporates readily into dimyristoyl phosphatidylcholine (DMPC) bilayer membranes; and an approximate penetration profile was obtained from the depth dependence of the perturb...

We reexamine a critical phenomenon of phospholipids in lamellar phases. The question is, Is the anomalous divergence in the repeat spacing near the main transition the result of a divergence of the water layer or of the lipid bilayer? X-ray diffraction of DLPC lamellae was measured in partially dehydrated conditions. Its critical behavior is much more pronounced than the previously studied DMPC...

The interaction of melittin, the major protein component of bee venom, with dimyristoyl phosphatidylcholine ( DMPC ) liposomes was investigated by Electron Spin Resonance (ESR) spectroscopy using high resolution amphiphilic spin probe perdeutero-di-t-butyl nitroxide (PDDTBN). For pure DMPC liposomes, ESR signal due to the probe dissolved in the fluid hydrophobic environment provided by the inte...

Aristotelia chilensis (Mol.) Stuntz (A. chilensis), also known as maqui, is a plant of the Elaeocarpaceae family that grows in central and southern Chile as well as southwestern Argentina. Infusions of its leaves have long been used in the traditional native herbal medicine to treat different ailments. Phytochemical studies of the plant's chemical composition of the plant indicate the presence ...