Author(s): Franzitta, Marco ; Feijão, Eduardo ; Cabrita, Maria Teresa ; Gameiro, Carla ; Matos, Ana Rita ; Marques, João Carlos ; Goessling, Johannes W. ; Santos, Patrick Reis ; Fonseca, Vanessa F. ; Pretti, Carlo ; Caçador, Isabel ; Duarte, Bernardo
Date: 2020
Persistent ID: https://hdl.handle.net/10316/101300
Origin: Estudo Geral - Universidade de Coimbra
Subject(s): CuO nanoparticles; photobiology; oxidative stress; lipid metabolism; phytoplankton; cytotoxicity; marine systems
Increasing input of Metal Engineered Nano Particles (MeENPs) in marine ecosystems has raised concerns about their potential toxicity on phytoplankton. Given the lack of knowledge on MeENPs impact on these important primary producers, the effects of Copper Oxide (CuO) ENPs on growth, physiology, pigment profiles, fatty acid (FA) metabolism, and oxidative stress were investigated in the model diatom Pheodactylum tricornutum, to provide suitable biomarkers of CuO ENP exposure versus its ionic counterpart. Diatom growth was inhibited by CuO ENPs but not Ionic Cu, suggesting CuO ENP cytotoxicity. Pulse Modulated Amplitude (PAM) phenotyping evidenced a decrease in the electron transport energy flux, pointing to a reduction in chemical energy generation following CuO ENPs exposure, as well as an increase in the content of the non-functional Cu-substituted chlorophyll a (CuChl a). A significant decrease in eicosapentaenoic acid (C20:5) associated with a significant rise in thylakoid membranes FAs reflected the activation of counteractive measures to photosynthetic impairment. Significant increase in the omega 6/omega 3 ratio, underline expectable negative repercussions to marine food webs. Increased thiobarbituric acid reactive substances reflected heightened oxidative stress by CuO ENP. Enhanced Glutathione Reductase and Ascorbate Peroxidase activity were also more evident for CuO ENPs than ionic Cu. Overall, observed molecular changes highlighted a battery of possible suitable biomarkers to efficiently determine the harmful effects of CuO ENPs. The results suggest that the occurrence and contamination of these new forms of metal contaminants can impose added stress to the marine diatom community, which could have significant impacts on marine ecosystems, namely through a reduction of the primary productivity, oxygen production and omega 6 production, all essential to sustain heterotrophic marine life.
The authors would like to thank Fundação para a Ciência e a Tecnologia (FCT) for funding the research via project grants PTDC/CTA-AMB/30056/2017 (OPTOX), UIDB/04292/2020, and UID/MULTI/04046/2013. BD and VF were supported by investigation contracts (CEECIND/00511/2017 and DL57/2016/CP1479/CT0024). PR-S was supported by FCT through a postdoctoral grant (SFRH/BPD/95784/2013). JG was supported by co-funding through the NanoTRAINforGrowth II Program (project 2000032) by the European Commission through the Horizon 2020 Marie Skłodowska-Curie COFUND Program (2015), and by the International Iberian Nanotechnology Laboratory.
