Mestrado em Engenharia do Ambiente - Tecnologias Ambientais - Instituto Superior de AgronomiaOxidative damage and antioxidant responses induced by Cu2+ and tryptamine on cyanobacteria
(Anabaena sp. and Aphanizomenon gracile) and chlorophyte (Ankistrodesmus falcatus) were
analyzed to determine if these species have different efficiency for the removal of ROS. Cu2+
and tryptamine induced higher levels of MDA, a lipid-peroxidation product, and consequently
more oxidative damage, in the cyanobacteria than in chlorophyte. This is probably related to the
higher induction of CAT and APX in A. falcatus, which leads this isolate to a more efficient
scavenging of H2O2. While no significant changes in CAT activity were detected, both cultures
showed an increased in APX activity following tryptamine exposure treatments. On the other
hand, A. falcatus showed a significant (p <0,05) increase in CAT and APX activity after 24 hours
exposure to 50 μM Cu 2+, indicating the involvement of these enzymes in H2O2 scavenging.
These results suggest that the cellular defense mechanisms triggered by A. gracile were less
efficient than the ones triggered by A. falcatus for the removal of ROS. Therefore Anabaena sp.
might be more stress susceptible and A. falcatus more stress-tolerant specie
