Isolated and combined effects of thermal stress and copper exposure on the trophic behavior and oxidative status of the reef-building coral Mussismilia harttii

Elevated Temperature and Exposure to Copper Leads to Changes in the Antioxidant Defense System of the Reef-Building Coral Mussismilia harttii

“…This result was paralleled to increased GST activity and increased GSH levels in corals. Interestingly, increased temperature reduced the levels of LPO in the symbionts ( Fonseca et al, 2021 ) and no changes were observed in the present study in GST activity and GSH levels. These results suggest a significant role of the glutathione system in the detoxification of LPO metabolites in corals and symbionts.…”

“…Oxidative stress is defined as an imbalance in the pro-oxidant/antioxidant ratio, which favors increased pro-oxidants and results in oxidative damage ( Downs et al, 2002 ; Halliwell and Gutteridge, 2007 ). Previous studies have shown that the elevated temperature and exposure to Cu are typically known to induce oxidative damage in M. harttii ( Fonseca et al, 2017 ; Marangoni et al, 2017 , 2019a , b ; Fonseca et al, 2021 ), as well as in other coral species ( Lesser, 1997 ; Schwarz et al, 2013 ; Dias et al, 2019 ). Given the clear connection between oxidative stress and coral bleaching (for a review see Suggett and Smith, 2019 ), it is paramount to evaluate changes in the activity of specific antioxidant molecules that are associated with this condition.…”

“…In fact, Fonseca et al (2017) showed a reduction in lipid damage (as lipid peroxidation) in M. harttii exposed for up to 12 days under the same experimental conditions. Later, an increase in total antioxidant capacity (TAC) in algae symbionts of M. harttii was observed after exposure to increasing temperature and Cu ( Fonseca et al, 2021 ). Interestingly, South Atlantic corals have been suggested to be more tolerant to stressors compared to coral reefs in other parts of the world ( Mies et al, 2020 ).…”

“…GST is an enzyme of the phase II of the detoxification processes responsible for conjugating GSH with many organic and inorganic compounds, including aldehydes produced during lipid peroxidation (LPO; Higgins and Hayes, 2011 ). In fact, it has been shown that exposure to increased temperature alone induces LPO in host corals after prolonged exposure ( Fonseca et al, 2021 ). This result was paralleled to increased GST activity and increased GSH levels in corals.…”

“…The antioxidant defense parameters were quantified in both coral host and endosymbiont microalgae fractions. Samples were prepared as described by Fonseca et al (2021) . Coral fragments were cut, homogenized on ice with a buffer for each analysis (1:1 w/v) using a sonicator (20 kHz, Sonaer Ultrasonics ® , New York, United States).…”