Fluctuations and Fractal Noise in Biological Membranes

Abstract

Our understanding of cell structure and function derives from applications of a variety of physical and life science disciplines, methods and models to an important physiological process, namely, the exchange and transport of ions and molecules across biological membranes. We know that ion transport through membranes arises from a diversity of interrelated and interactive physical and chemical phenomena over a wide range of spatial and temporal scales. Among these phenomena common to all cellular structure and function include metabolism, kinetics of molecules, chemically mediated alteration of cell membrane electrical potential, membrane ion conductance, electrical signal propagation, and modulation by chemo- and mechanoreceptive mechanisms. This review focuses on the unique information contained in fluctuations in electrical properties associated with cell membrane ion transport.

Many length scales surface fractality in monomolecular films of whole myelin lipids and proteins

“…Fractality has been invoked in the Weld of membrane biophysics in connection with a number of phenomena ranging from the geometry of self-aggregated vesicles (Lahiri et al, 1998), the folding of the membrane in 3D space (Paumgartner et al, 1981), the kinetics of channel conductance (Hoop and Peng, 2000), experimentally observed lipid domain topography (Miller et al, 1986) and its simulation (Fogedby et al, 1987), and lateral surface defects or diVusion (Nonnenmacher, 1989;Pink et al, 1991). In connection with lipid domains the focus has traditionally been on the determination of percolation thresholds of bilayer domains at thermotropic phase transition points through Xuorescence recovery after photobleaching (FRAP) experiments (Almeida and Vaz, 1995).…”

Recurrent fractal neural networks: a strategy for the exchange of local and global information processing in the brain

“…hydrophobic or van der Waals interactions between membrane lipids, may be programmed by incoming synaptic signals that modulate the shape of a spatially extended, fractal lipid lattice or microdomain (Bieberich, 2000a). Recently, it has been found that biological membranes exhibit requisite characteristics of fractal geometry with respect to curvature, shape, and internal molecular organization (Hoop and Peng, 2000;Rabouille et al, 1992;Sugar et al, 2001). Alternatively, microtubules or other filaments of the cytoskeleton may also form a lattice structure that can be shaped into a fractal.…”

Different modulation of phospholipase A2 activity by saturated and monounsaturated N-acylethanolamines

“…Many important physiological membrane functions [such as enzymatic activities, membrane permeability, hormonal response, etc. (18)(19)(20)] are modulated by physico-chemical properties of the lipid bilayer. For example, many physiological processes involve changes in the amount of water bound to lipid bilayer (20), which affects, in particular, the membrane interfacial polarity.…”