BioProject

Understanding the mode of action of nanomaterials (NMs) aids in improving predictions and environmental risk assessment. More...

Understanding the mode of action of nanomaterials (NMs) aids in improving predictions and environmental risk assessment. In the present study, a high-throughput (HTP) microarray was used to study Enchytraeus crypticus gene expression. Four Ag materials (Ag NM300K, PVP-coated AgNPs, AgNPs, and AgNO3) were tested at reproduction effect concentrations, EC20 and EC50, to anchor gene expression responses to higher effect level. The results showed that while PVP-AgNPs and AgNPs had similar responses, Ag NM300K caused effects via a differentiated transcriptomic profile, with uniquely affected processes (e.g. transcytosis). For the AgNPs, the EC50 negatively affected apoptosis, which can lead to accumulation of abnormal cells and cause apical damage (reproduction). Mechanisms which are known to be related to Ag toxicity and which were observed here for the various Ag forms included apoptosis regulation, cell redox homeostasis, impairment of energy production and response to DNA damage. This HTP genomic tool enabled discrimination between Ag materials, which is not possible via standard tests (i.e. survival and reproduction endpoints). Moreover, gene expression analysis provided information regarding the mechanisms of toxicity of NMs and the pathways uniquely affected by NMs. An adverse outcome pathway (AOP) was drafted for the first time for Ag NMs; this AOP can and should be used as a basis for further research. Overall design: Gene expression profile of Enchytraeus crypticus was analysed after 3 and 7 days of exposure to the EC20 and EC50 (effect concentrations on reproduction) of three silver nanomaterials (Ag-NPs PVP-Coated, Ag-NPs Non-Coated and Ag NM300K) and silver salt (AgNO3) in LUFA 2.2 soil. Three biological replicates per test treatment and controls (un-spiked LUFA soil for AgNO3, Ag-NPs PVP-Coated and Ag-NPs Non-Coated; and LUFA soil mixed with the NM300K dispersants _tween 20 for the Ag NM300K) were used. Less...