“EFECTO DE LA FRACCIÓN HIDROSOLUBLE DEL PETRÓLEO SOBRE EL METABOLISMO LIPÍDICO DE CRUSTÁCEOS”

LAVARIAS, SABRINA MARIA LUISA; DREON, M.; GARCÍA, F.; POLLERO, R.; HERAS, H.

Misiones, Argentina

Congreso; XL Reunión de la Sociedad Argentina de Investigación Bioquímica (SAIB); 2004

SAIB

The effect of the water-soluble fraction (WSF) from crude oil on lipid classes, phosphatidylcholine (PC) molecular species, membrane fluidity and microsomal enzymes was studied in hepatopancreas (HP) and eggs of the freshwater crustacean M. borellii. After 7-day exposure to sublethal concentration of WSF (0.6 ppm), a triacylglicerol/phospholipid ratio increased in HP and decreased in eggs, suggesting alterations either in the mobilization of triacylglycerols to phospholipid pools or in the energy balance. WSF exposure altered PC molecular species in both tissues. From the 15 species identified, the 4 major HP molecular species (16:0/18:1, 18:1/18:2, 16:0/20:5 and 16:1/20:5) and most other PUFA-containing ones decreased. This was compensated by an increase in 16:1/18:1 (152 %) and 18:1/18:1 (50 %). The major egg PC molecular species decreased (16:0/18:1 and 18:1/18:2), while PUFA-containing ones increased their proportion. Nevertheless, microsomal membrane fluidity was not altered by WSF exposure. The microsomal palmitoyl-CoA ligase activity increased significantly in HP (154%) and eggs (89%). Total acylglycerides synthesis also increased in both tissues (21 and 61%, respectively) though the radioactive tracer was incorporated into different lipids. The contrasting response of both tissues to WSF contamination suggests the presence of different homeostatic mechanisms. The increase of enzymatic activities might be due to their synthesis induction or a mechanism of activation and not to changes in membrane properties.