CIQUIBIC   05472
CENTRO DE INVESTIGACIONES EN QUIMICA BIOLOGICA DE CORDOBA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
of polyelectrolytes on the rheological properties of lipid monolayers
Autor/es:
C.I. CÁMARA, N. WILKE
Lugar:
SIERRA DE LA VENTANA
Reunión:
Congreso; 'XLIII Reunión Anual de la Sociedad Argentina de Biofísica; 2014
Resumen:
Glycosaminoglycans (GAGs) are important constituents
of the extracellular matrix of microorganisms, animals and plants. These are
large polymers formed by mono, di or oligo-saccharides bounded by glycosidic
linkages. These polyelectrolyte may have a variety of functional groups along
his chain. Within these polysaccharides can find functionalized dextran sulfate
(DS, negatively charged), and di-ethyl-amino-ethyl dextran (DEAE, positive
polysaccharide). Although polysaccharides (negatively charged) have been
associated with biological function into the membrane and, through it, their
specific role is not known, and it has been reported that its presence affects
the dynamics of lipids and proteins. The aim of this work is to study how the
presence of different polysaccharides modifies the rheological properties of
model membranes. This will be used as models of membrane lipid monolayers of
dimyristoyl phosphatidyl glycerol (DMPG) and diPALMITOILphosphatidylcholyne
(DPPC).The polysacharyd studied were DS of high (DSA) and low (DSB) sulphate
content, and di-ethyl-amino-ethyl dextran (DEAE). DMPG and DPPC films were
formed over a subphase CaCl2 (10 mM) and NaCl (145mm), under this
conditions both lipids have a phase transition from liquid expanded to liquid
condensed phase- about 15mN / m and 7,5 mN/m for DMPG and DPPC, respectively.
When the monolayer is formed in the presence of DSB, any changed in the
isotherm of both lipids were found. In the case of DSA the effect on the
isotherm depends of the lipid. In contrast, in presence of DEAE the expanded
phase of both lipids was stabilized. Whit the aim of completes the
caracaterization of the system the diffusion coefficients of condensed domains
and the viscosity of the expanded phase were measure under all conditions.