39
Pyropia orbicularis (Bangiophyceae), Contreras-Porcia et  al. (2011a) found that
PRX activity and gene expression significantly increased. Similarly, when the green
alga U. compressa was exposed to copper excess for 7 days, genes encoding for PRX
and its reducing agent, thioredoxin, significantly increased (Contreras-Porcia et al.
2011b), and in S. gracilis PRX protein levels increased under copper excess
(Lovazzano et al. 2013). These results suggest that PRX acts as an active antioxidant
Fig. 3.1 Mechanisms involved in the tolerance to heavy metal stress in seaweeds. ABC transporter
(ABC); calmodulin (CAM); chloroplast (chl); glutathione (GSH); glutathione S-transferase (GST);
heavy metals like Cd, Cu, Pb, and others (M); polyphosphate bodies (PPBs); reactive oxygen species (ROS); vacuole (va). Some enzymes involved in these mechanisms are catalase (CAT), ascorbate peroxidase (AP), peroxiredoxin (PRX), and lipoxygenase (LOX), among others
3 Marine Metal Pollution and Effects on Seaweed Species