Folgueira López, IriaLamas Fernández, JesúsFelipe González, Ana Paula deSueiro Benavides, Rosa AnaLeiro Vidal, José Manuel2020-03-312020-03-312019Folgueira, I., Lamas, J., de Felipe, A.P. et al. Identification and Molecular Characterization of Superoxide Dismutases Isolated From A Scuticociliate Parasite: Physiological Role in Oxidative Stress. Sci Rep 9, 13329 (2019). https://doi.org/10.1038/s41598-019-49750-5http://hdl.handle.net/10347/21027Philasterides dicentrarchi is a free-living microaerophilic scuticociliate that can become a facultative parasite and cause a serious parasitic disease in farmed fsh. Both the free-living and parasitic forms of this scuticociliate are exposed to oxidative stress associated with environmental factors and the host immune system. The reactive oxygen species (ROS) generated by the host are neutralized by the ciliate by means of antioxidant defences. In this study we aimed to identify metalloenzymes with superoxide dismutase (SOD) activity apable of inactivating the superoxide anion (•O2−) generated during induction of oxidative stress. P. dicentrarchi possesses the three characteristic types of SOD isoenzymes in eukaryotes: copper/zinc-SOD, manganese-SOD and iron-SOD. The Cu/Zn-SOD isoenzymes comprise three types of homodimeric proteins (CSD1-3) of molecular weight (MW) 34–44kDa and with very diferent AA sequences. All Cu/Zn-SODs are sensitive to NaCN, located in the cytosol and in the alveolar sacs, and one of them (CSD2) is extracellular. Mn- and Fe-SOD transcripts encode homodimeric proteins (MSD and FSD, respectively) in their native state: a) MSD (MW 50kDa) is insensitive to H2O2 and NaN3 and is located in the mitochondria; and b) FSD (MW 60kDa) is sensitive to H2O2, NaN3 and the polyphenol trans-resveratrol and is located extracellularly. Expression of SOD isoenzymes increases when •O2 − is induced by ultraviolet (UV) irradiation, and the increase is proportional to the dose of energy applied, indicating that these enzymes are actively involved in cellular protection against oxidative stresseng© Te Author(s) 2019. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Te images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/https://creativecommons.org/licenses/by/4.0/Scuticociliate ParasitePhilasterides dicentrarchiParasitic diseaseFarmed fishOxidative stressjournal article10.1038/s41598-019-49750-52045-2322open access