Lipid peroxidation studies in Euglena gracilis grown in heterotrophic and autothrophic conditions.

ROCCHETTA IARA, RUIZ LAURA, CONFORTI VISITACIÓN AND RÍOS DE MOLINA MARÍA C.

Buenos Aires

Congreso; Society of Free Radical Research International (SFRR), XII Biennial Meeting,; 2004

Society of Free Radical Research International (SFRR)

Euglena gracilis shows metabolic and morphological changes when it is exposed to different stress conditions. Lipid peroxidation studies were carried out in cells grown in presence of different concentration of hexavalent chromium. The strain UTEX 753, from a Centre Culture Collection, and its non-photosynthetic mutant (white cell) were used for this study. Cellular growth of both strains decreased according to the metal concentration used. The greatest levels of TBARS were induced by the highest metal concentration, which indicated events of lipid peroxidation. Despite of this, total lipid content was increased when the highest amount of chromium was added. Although both strains have different fatty acid compositions in control cells, they showed similar response to the metal presence. The green cells have a higher  polyunsaturated fatty acids (PUFAs) total content, meanwhile the white cells have a higher saturated fatty acids (SAFAs) content. Among the PUFAs, the photosynthetic cells showed high levels of linolenic and oleic acids (w3) and in the white ones arachidonic acid (w6) was the most important. This acid showed a high increased in chromium treated cells, being more remarkable in the white cells. These results could be related with the activation of phospholipase A2 which led to the generation of AA, which activates a reactive oxygen species (ROS) production pathway.