Proteomics and antioxidant enzymes reveal different mechanisms of toxicity induced by ionic and nanoparticulate silver in bacteria

• Autor(a) principal: Barros, Diana
• Data de Publicação: 2019
• Outros Autores: Pradhan, Arunava, Mendes, Vera M., Manadas, Bruno, Santos, P. M., Pascoal, Cláudia, Cássio, Fernanda
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/1822/72985
• topic: Ciências Naturais::Ciências Biológicas; Engenharia e Tecnologia::Biotecnologia Ambiental; Science & Technology

The increased use of silver nanoparticles (AgNPs) raises concerns about their impacts on aquatic ecosystems. The impacts of Ag+ and AgNPs were assessed on proteomic and antioxidant enzymatic responses of Pseudomonas sp. M1. The effects of Ag+ on bacterial growth were stronger than those of AgNPs (EC20 = 107.1 μg L−1 for Ag+; EC20 = 307.2 μg L−1 for AgNPs), indicating the lower toxicity of the latter. At EC20, the activities of antioxidant enzymes increased more under exposure to Ag+ than to AgNPs, particularly for superoxide dismutase and glutathione peroxidase (stimulation of 667% and 433%, respectively). A total of 166 proteins were identified by SWATH-MS; among these, only 59 had their content significantly altered by one or both forms of silver. Exposure to AgNPs resulted in an increase of about 54% of these proteins, whereas 54% decreased under exposure to Ag+. Gene Ontology enrichment analysis revealed that protein folding and transmembrane transport were the most relevant processes affected by Ag+ exposure, whereas AgNPs mostly affected translation. Also, results suggest that each form of silver induced different adaptive responses. Furthermore, the low levels of Ag+ released from AgNPs (<0.1%) support a minor role of dissolved silver in AgNP toxicity to Pseudomonas sp. M1