The Micomonas commoda response to metaloxide nanoparticule exposure

Engineered nanoparticles (ENPs) are increasingly used to generate innovative industrial and medical goods. Because of their broad applications, they form a new class of pollutants with potential eco-toxicological impacts on marine ecosystems. Attempting to evaluate the risk, we investigated the toxicity of Iron and Zinc oxide ENPs on three picophytoplanktonic strains of algae: Micromonas commoda, Ostreococcus tauri and Nannochloris sp. Microalgae responses are highly species-dependent, Micromonas commoda growth being severely impaired by both ENP types whereas Ostreococcus tauri or Nannochloris sp. are resistant. ZnO ENPs have higher toxicity than iron ENPs though growth of M. commoda was severely inhibited by Fe2O3 ENPs. Transcriptome-wide analysis after exposure of M. commoda to ENPs shows that the altered biological processes mainly take place in the cytoplasm and that the response to ENPs is largely metabolic in nature: stimulation of carbohydrate metabolism, light harvesting processes and alteration of the nitrogen pathway. In addition, a severe disruption of ribosome structure and translation processes is observed. Overall design: mRNA profiles of Micromonas commoda cultures either control or after 48h metaloxide nanoparticles exposure were generated using Illumina HiSeq 3000