Domoic Acid Oxidative Effects on the Microalgae Phaeodactylum tricornutum

Domoic acid (DA) is a natural occurring marine biotoxin. Oxidative stress generation due to DA exposure was reported in animals, but little is known on the phytoplankton community. The aim of this work was to verify whether exposure to DA in the marine diatom Phaeodactylum tricornutum favors reactive oxygen species (ROS) generation in the intracellular environment modifying its antioxidant capacity. Active species production, non-enzymatic antioxidant content, and antioxidant enzyme activities over the three growth phases of P. tricornutum exposed to 64 mu M DA were evaluated. Results obtained in exponential growing cells showed a time-depending seven-fold increase in the 2',7' dichlorofluorescein diacetate dye oxidation rate. Superoxide dismutase and catalase activities showed a two-fold increase, and glutathione related enzymes activities were also significantly increased in treated diatoms as compared to controls. However, glutathione and ascorbate contents significantly decreased after incubation of the cells with DA. Similar effects were observed in latent and stationary phases of cell development. These results showed that DA could cause a severe oxidant-dependent impact on a non-toxic algae.

Automated summary

This study aimed to investigate the effects of exposure to domoic acid (DA) on the marine diatom Phaeodactylum tricornutum. The results showed that exposure to DA led to an increase in reactive oxygen species (ROS), as well as changes in antioxidant capacity. The enzyme activities and antioxidant content in the diatoms were significantly affected by DA exposure.