Membranes organization

Hankamer, B., Barber,/, and Boekema, E. J., 1997. Structure and membrane organization of photosystem II in green plants. Annual Review of Plant Physiology and Plant Molecular Biology 48 641—671. 

Monensin, which is one of the natural antibiotics, selectively transports Na+ across an artificial liquid membrane (organic solvent) from the basic aqueous phase (IN) to the acidic aqueous phase (OUT), driven by the proton gradient8). (Fig. 1, 2)... 

Phospholipids are found widely in both plant and animal tissues and make up approximately 50% to 60% of cell membranes. Because they are like soaps in having a long, nonpolar hydrocarbon tail bound to a polar ionic head, phospholipids in the cell membrane organize into a lipid bilayer about 5.0 nm (50 A) thick. As shown in Figure 27.2, the nonpolar tails aggregate in the center of the bilayer in much the same way that soap tails aggregate in the center of a micelle. This bilayer serves as an effective barrier to the passage of water, ions, and other components into and out of cells. 

Zerial M, McBride H (2001) Rab proteins as membrane organizers. Nat Rev Mol Cell Biol 2 107-117... 

Jaffe, C.L., Lis, H., and Sharon, N. (1980) New cleavable photoreactive heterobifunctional cross-linking reagents for studying membrane organization. Biochemistry 19, 4423. 

Mechanical functions of cells require interactions between integral membrane proteins and the cytoskeleton 29 The spectrin-ankyrin network comprises a general form of membrane-organizing cytoskeleton within which a variety of membrane-cytoskeletal specializations are interspersed 29 Interaction of rafts with cytoskeleton is suggested by the results of video microscopy 29... 

Eukaryotic cells have evolved a complex, intracellular membrane organization. This organization is partially achieved by compartmentalization of cellular processes within specialized membrane-bounded organelles. Each organelle has a unique protein and lipid composition. This internal membrane system allows cells to perform two essential functions to sort and deliver fully processed membrane proteins, lipids and carbohydrates to specific intracellular compartments, the plasma membrane and the cell exterior, and to uptake macromolecules from the cell exterior (reviewed in [1,2]). Both processes are highly developed in cells of the nervous system, playing critical roles in the function and even survival of neurons and glia. 

Membranes and models membrane organization (e.g. membrane domains, lipid distribution, peptide association, lipid order in vesicles, membrane fusion assays, etc.)... 

Because this area is not too well known, the authors have taken pains to describe, in some detail, experimental monolayer chemistry. The centerpiece of the chapter is enantiomer and diastereomer discrimination in monolayers. It concludes with a discussion of surface properties, in particular energetics, which are quite sensitive to stereochemistry. We call attention to the fact that this chapter is of potential interest to biochemists, notably those concerned with lipids and with cell membrane organization. 

Emmelot, P. and Van Hoeven, R.P., 1975 Phosphohpid rmsaturation and plasma membrane organization. Chem. Phys. Lipids. 14 236-246. 

Chalcone synthase, the first enzyme committed to flavonoid biosynthesis, is a membrane-bound protein (40). Since it is readily solubilized, it had previously been regarded as a soluble enzyme. Likewise, DS-Co and CM-2 may prove to be membrane-organized proteins that are readily solubilized. 

Israelachvilli JN, Matcelja S, Horn RG. Physical principles of membrane organization. Q Rev Biophys 1980 13 121-200. 

Neubig, R. R. (1994). Membrane organization in G-protein mechanisms. FASEB J. 8, 939-946. 

Membrane effects. Drugs may alter synaptic transmission by affecting membrane organization and fluidity. Membrane fluidity is basically... 

A. W. Wolkoff, Hepatocellular sinusoidal membrane organic anion transport and transporters, Semin. Liver Dis. 76 121-127 (1996). 

Ecoscope Hexane (organics) chelating resin (metals) Polyethylene membrane (organics), porous membrane (metals) Hydrophobic organic compounds, heavy metals Qualitative screening 2-4 weeks Direct injection of solvent or after concentration or extraction with acid 59... 

Membranes can be classified as porous and nonporous based on the structure or as flat sheet and hollow fiber based on the geometry. Membranes used in pervaporation and gas permeation are typically hydrophobic, nonporous silicone (polydimethylsiloxane or PDMS) membranes. Organic compounds in water dissolve into the membrane and get extracted, while the aqueous matrix passes unextracted. The use of mircoporous membrane (made of polypropylene, cellulose, or Teflon) in pervaporation has also been reported, but this membrane allows the passage of large quantities of water. Usually, water has to be removed before it enters the analytical instrument, except when it is used as a chemical ionization reagent gas in MS [50], It has been reported that permeation is faster across a composite membrane, which has a thin (e.g., 1 pm) siloxane film deposited on a layer of microporous polypropylene [61],... 

Fluorescence probes are frequently used to study changes in membrane organization and membrane fluidity induced by anesthetics, various drags, and insecticides. This technique measures fluidity as the rate and extent of phospholipid acyl chain excursion away from some initial chain orientation during the lifetime of the excited fluorescence state. Special techniques even allow the place of interaction to be localized, i.e. to the outer membrane region, the hydrophobic area, or the embedded proteins. 

As discussed below, new knowledge about cell membrane ultrastructure emphasizes the importance of a layer of stranded glycoprotein material external to the lipid bilayer in a wide range of functions. These functions range from modulation of transmembrane ion fluxes through membrane ion channels to formation of receptor sites for antibody molecules. These capabilities depend in great measure on the polyanionic terminal structure of these stranded protrusions. Clearly, the two examples cited present extremes in the complexities of membrane organization. Nevertheless, both types of process exhibit similar sharp transitions as a function of temperature that are consistent with cooperative processes. 

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