Animal Cell Membranes as Substrata for Bacterial Adhesion

摘要: The purpose of this chapter is to review briefly the composition and organization animal cell surface structures that may be potential receptors for adhesins bacteria. understanding specificity cell—bacteria interactions requires a basic knowledge molecular structure surface, especially those molecules serve as ligands in general bacterial particular. All membranes share common compositional organizational features (Figure 3-1): (1) major membrane lipids are arranged planar bilayer configuration predominantly “fluid” state under physiological conditions. commonly composed glycerolphospholipids, sphingolipids, sterols. (2) contains integral constituents both glycolipids glycoproteins inserted or “intercalated” into structure. (3) Other proteins bound plasma by weak ionic interactions, hydrogen bonding, hydrophobic effect. These surface-associated referred peripheral extrinsic components. (4) In many cells there substantial layer carbohydrate-containing materials variable thicknesses outside but close intimate association with membrane. This known coat extracellular matrix. distinction between being integral, peripheral, belonging based on method required dissociate constituent question from released only after disruption perturbation phospholipid bilayer, usually detergents (Lichtenberg et al., 1983). Nonintegral washing buffers different pH strength, using chelating agents, such ethylenediaminetetraacetic acid (EDTA). There no method, however, release selectively either matrix constituents. As result, two classes sometimes difficult resolve very often they nonintegral One key its asymmetry. For nonglycosylated asymmetry partial, every present sides amounts. human erythrocytes, example, positively charged head groups (e.g., phosphatidylethanolamine phosphatidylserine) predominant internal leaflet facing cytoplasm (Marinetti Crain, 1978). respect proteins, glycoproteins, absolute: molecule given has same orientation across lipid carbohydrate moieties glycosylated compounds always exposed outer surface. further information membrane, reader reviews (Lodish 1981; Lotan Nicolson, Singer, Aplin Hughes, 1982) book (Sim, 1982).