title: X-ray diffraction analysis of internal wool lipids.
abstract: Polarised optical microscopy (POM) and X-ray diffraction techniques were applied to intercellular lipids extracted from wool to study their structural arrangement in order to determine their role in the diffusion properties of wool fibre. Intercellular wool lipids (IWL) arranged as concentrated liposomes were shown to be a good intercellular lipid model, allowing their study by X-ray diffraction techniques. The results confirm that intercellular lipids of wool fibre are organised in a lamellar structure of 5.0-8.0 nm width, termed beta-layer, which had been assumed to be lipids arranged as a bilayer. Structurally, internal wool lipids are distributed at least in two domains at low temperatures: an ordered phase made up of ceramides and free fatty acids (FFA) alone, arranged in crystal orthorhombic states separately, and a liquid crystal state when mixed together. At 40 degrees C there is a reversible phase transition produced by the melt of the crystal orthorhombic states, whereas the liquid crystal state remains until 65 degrees C.
authors.affiliation: Instituto de Investigaciones Químicas y Ambientales de Barcelona, C.S.I.C. Jordi Girona 18-26, 08034, Spain.
authors.forename: Jordi
authors.initials: J
authors.lastname: Fonollosa
authors.forename: Lourdes
authors.initials: L
authors.lastname: Campos
authors.forename: Meritxell
authors.initials: M
authors.lastname: Martí
authors.forename: Alfons
authors.initials: A
authors.lastname: de la Maza
authors.forename: José Luis
authors.initials: JL
authors.lastname: Parra
authors.forename: Luisa
authors.initials: L
authors.lastname: Coderch
mesh_terms: D000818:Animals; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry; D008853:Microscopy; D011489:Protein Denaturation; D013696:Temperature; D014867:Water / Q000032:analysis / Q000737:chemistry; D014935:Wool / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D008055:Lipids; D008081:Liposomes; D014867:Water