Engineered nanoceria alleviates thermally induced oxidative stress in free-living Breviolum minutum (Symbiodiniaceae, formerly Clade B)

The breakdown of symbiotic mutualism between cnidarian hosts and dinoflagellate algae partners (i.e., bleaching) has been linked to an immune-like response pathway brought on by a nitro-oxidative burst, symptom thermal stress. Stress induced reactive oxygen species (ROS)/reactive nitrogen is problem common aerobic systems. In this study, we tested the antioxidant effects engineered poly(acrylic acid)-coated cerium dioxide nanoparticles (CeO 2 , nanoceria) free-living Symbiodiniaceae ( Breviolum minutum ), alga that forms relationships with reef-building corals anemones. Results show CeO hydrodynamic diameters ~4 nm are internalized B. in under 30 min subsequently localized cytosol. Nanoceria exposure does not inhibit cell growth over time, treated cultures showing similar trend 25-day exposure. Aerobic activity stress when held at 34°C for 1 h (+6°C above control) led increased intracellular ROS concentration time. A clear scavenging effect nanoceria was observed, 5-fold decrease levels during nitric oxide (NO) decreased ~17% stress, suggesting rapid involvement NO enzymes or proteins within onset. presence did appear influence concentration. Furthermore, aposymbiotic anemones Exaiptasia diaphana ex Aiptasia pallida ) were successfully infected nanoceria-loaded demonstrating inoculation could serve as delivery method. ability be taken up reduce production leveraged potential mitigation strategy coral bleaching.