IIBYT   23944
INSTITUTO DE INVESTIGACIONES BIOLOGICAS Y TECNOLOGICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Comparative study of insect and mammals neuronal membranes: Microviscosity, interfacial behavior and morphology of the transferred films.
Autor/es:
NICOLAS G COLMANO; ANAHI V. TURINA; SANCHEZ M.E; EDUARDO M. CLOP
Lugar:
La Plata
Reunión:
Congreso; XLVII Reunión Anual de la Sociedad Argentina de Biofísica; 2018
Institución organizadora:
Sociedad Argentina de Biofisica
Resumen:
Interfacial behavior, molecular organization and composition of neuronal membranes from very different animal source are reported. Neuronal membranes were obtained from synaptosomal membranes (SM) of bovine brain cerebral cortex and ganglionar membranes (GM) of dissected cerebral ganglia of Triatoma infestans nymphs (V instar).SM and GM ?A isotherms showed a liquid expanded behaviour with a bidimensional phase transition at 36 mN/m in SM isotherm whereas GM films showed a more expanded and less cooperative transition at 17mN/m. GM films appeared to be less stable at high  (col-SM = 45 mN/m and col-GM= 36 mN/m)A noticeable hysteresis was observed between the compression-decompression (C-D) cycle of both SM and GM isotherms. The G between these two states was higher to GM than to SM reflecting the more plastic characteristic of the GM monolayer (GGM=64.3 KJ and GSM=22.4KJ). The floating monolayer was transferred to a solid support using the Langmuir Schaefer mode (LS films). Images obtained from LS films by epifluorescence microscopy allowed us to appreciate the complex topology present in natural membranes, with some structures not observed in the air-water interface. LS films of GM presented structures usually associated with protein agglomerates, that grew as  increased. In comparison, LS of SM showed a higher presence of condensed domains than observed in GM.Microviscosity was assessed by fluorescence anisotropy of DPH (ADPH) and TMA-DPH (ATMA-DPH). The values of ADPH suggest that the region of hydrocarbon chains in SM was more ordered than in GM. On the other hand, the ATMA-DPH values showed the opposite behavior.The differences observed in microviscosity, interfacial behavior and morphology of LS films could be related with the composition of these natural membranes, as cholesterol content is significantly lower in GM. Electrophoretic profiles allowed to compare the proteins bands presents in vesicles membranes as well as in the prepared films.