Photosynthetic, morphological and biochemical biomarkers as tools to investigate copper oxide nanoparticle toxicity to a freshwater chlorophyceae

Author(s)

Goncalves Alho, Lays de Oliveira ^{[1, 2]} ; Souza, Jaqueline Perola ^[3] ; Rocha, Giseli Swerts ^[4] ; Mansano, Adrislaine da Silva ^{[1, 2]} ; Lombardi, Ana Teresa ^{[5, 1]} ; Sarmento, Hugo ^{[1, 2]} ; Gama Melao, Mariada Graca ^{[1, 2]}

Affiliation

^[1] Univ Fed Sao Carlos, Dept Hydrobiol, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos UFSCar, Postgrad Program Ecol & Nat Resources PPGERN, Rodovia Washington Luis, 13565-905, BR-235 Sao Carlos, SP - Brazil

^[3] Univ Sao Paulo, Nanomed & Nanotoxicol Grp, Phys Inst Sao Carlos, Ave Trabalhador Sao Carlense 400, BR-13566590 Sao Carlos, SP - Brazil

^[4] Univ Sao Paulo, Sao Carlos Sch Engn, NEEA CRHEA SHS, Ave Trabalhador Sao Carlense 400, BR-13560970 Sao Carlos, SP - Brazil

^[5] Univ Fed Sao Carlos, Dept Bot, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Environmental Pollution; v. 265, n. A OCT 2020.
• Web of Science Citations: 9

Abstract

Copper oxide nanoparticles (CuO NP) have been produced on a large scale due to their economically interesting thermophysical properties. This heightens the concern about risks they may pose on their release into the environment, possibly affecting non-target organisms. Microalga are important organisms in ecotoxicological studies as they are at the base of the aquatic food chain, but information about their biochemical and photosynthetic changes in response CuO NP are still scarce. We studied the effects of CuO NP in Raphidocelis subcapitata using morphological, photosynthetic and biochemical biomarkers. Our results showed that the NP affected microalgal population growth with 0.70 mg Cu L-1 IC50-96 h (inhibition concentration). Based on predicted environmental concentrations of Cu NPs in aquatic environments, our results indicate potential risks of the NP to microalgae. Algal cell size, granularity and photosynthetic efficiencies were affected by the CuO NP at 0.97 and 11.74 mg Cu L-1. Furthermore, lipid metabolism was affected mostly at the highest NP concentration, but at environmentally relevant values (0.012 and 0.065 mg Cu L-1) the production of sterols (structural lipids) and triacylglycerols (reserve lipid) increased. Moreover, we found evidence of cell membrane impairment at the highest CuO NP concentration, and, as a photosynthetic response, the oxygen evolving complex was its main site of action. To the best of our knowledge, this is the first study to date to investigate microalgal lipid composition during CuO NP exposure, showing that it is a sensitive diagnostic tool. This research demonstrated that CuO NP may affect the physiology of R. subcapitata, and because they were observed in a primary producer, we foresee consequences to higher trophic levels in aquatic communities. (C) 2020 Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 18/07988-5 - Bioprospecting, characterization and optimization of Brazilian microalgal strains for CO2 biofixation and bioproducts of commercial importance
• Grantee: Ana Teresa Lombardi
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 16/00753-7 - Toxic effects of emerging microcontaminants on planktonic food webs
• Grantee: Maria da Graça Gama Melão
• Support Opportunities: Regular Research Grants
• FAPESP's process: 14/14139-3 - Microbial processes and biodiversity in aquatic ecosystems
• Grantee: Hugo Miguel Preto de Morais Sarmento
• Support Opportunities: Research Grants - Young Investigators Grants