Artículo
Phase state and surface topography of palmitoyl-ceramide monolayers
Fecha de publicación:
06/2010
Editorial:
Elsevier Ireland
Revista:
Chemistry and Physics of Lipids
ISSN:
0009-3084
e-ISSN:
1873-2941
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
In cell biology (and in many biophysical) studies there is a natural tendency to consider ceramide as a highly condensed, solid-type lipid conferring rigidity and close packing to biomembranes. In the present work we advanced the understanding of the phase behavior of palmitoyl-ceramide restricted to a planar interface using Langmuir monolayers under strictly controlled and known surface packing conditions. Surface pressure-molecular area isotherms were complemented with molecular area-temperature isobars and with observations of the surface topography by Brewster Angle Microscopy. The results described herein indicate that palmitoyl-ceramide can exhibit expanded, as well as condensed phase states. Formation of three phases was found, depending on the surface pressure and temperature: a solid (1.80nm thick), a liquid-condensed (1.73nm thick, likely tilted) and a liquid-expanded (1.54nm thick) phase over the temperature range 5-62 °C. A large hysteretic behavior is observed for the S phase monolayer that may indicate high resistance to domain boundary deformation. A second (or higher) order S→LC phase transition is observed at about room temperature while a first order LC→LE transition occurs in a range of temperature encompassing the physiological one (observed above 30 °C at low surface pressure). This phase behavior broadens the view of ceramide as a type of lipid not-always-rigid but able to exhibit polymorphic properties.
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Identificadores
Colecciones
Articulos(CIQUIBIC)
Articulos de CENTRO DE INVEST.EN QCA.BIOL.DE CORDOBA (P)
Articulos de CENTRO DE INVEST.EN QCA.BIOL.DE CORDOBA (P)
Citación
Fanani, Maria Laura; Maggio, Bruno; Phase state and surface topography of palmitoyl-ceramide monolayers; Elsevier Ireland; Chemistry and Physics of Lipids; 163; 6; 6-2010; 594-600
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