Caracterización Lipídica de Ovocitos de Bufo arenarum en el Estadio III de la Ovogénesis

BRUZZONE A; BUSCHIAZZO J; ALONSO TS

Tafí del Valle, Tucumán

Congreso; XVIII Jornadas Científicas Asociación de Biología de Tucumán; 2001

Asociación de Biología de Tucumán

Stage III oocytes, late vitellogenesis, have been described by Valdéz Toledo and Pisanó (1980) but they have not been biochemically characterized yet. Lipid level and their fatty acid composition were analyzed. Oocytes were manually isolated. Lipids were extracted according to Folch (1957), were separated by thin-layer chromatograpy and were methanolyzed for fatty acid composition studies. Fatty acid methyl esters were quantified in a gas-liquid chromatograph. Phosphorus phospholipidic was measured following Rouser (1970) and proteins according to Lowry (1951). Phosphoglycerides represent about 5% of total lipids. Phosphatidylcholine and phosphatidylethanolamine (PC and PE) are the main components followed by diphosphatidylglycerol (DPG), phosphatidylinositol (PI), phosphatidylserine (PS) and phosphatidic acid (PA). A high content of DPG, a mitochondrial lipid, was observed in comparison with stage V oocytes suggesting a major mitochondrial population. Palmitic and linoleic acids are important components in PC and PE. PI and PA are also enriched in arachidonic acid. Stearic and oleic acids are the main fatty acids in DPG. With respect to neutral lipids, triacylglycerides (TAG) are the major group followed by free fatty acids (FFA) and diacylglycerides (DAG). Unsaturation index indicate that TAG are more unsaturated (153) than DAG (129) and FFA (116).