Project description:Titanium dioxide (TiO2) based nanomaterials (NMs) are among the most produced NMs worldwide. When irradiated with light, particularly UV, TiO2 is photoactive, a property that is explored for several purposes. There is an increasingly number of reports on the negative effects of photoactivated TiO2 to non-target organisms. We have here studied the effect of a suite of reference type TiO2 NMs i.e. NM103, NM104, NM105 and compared these to the Bulk) with and without UV radiation to the oligochaete Enchytraeus crypticus. High-throughput gene expression was used to assess the molecular mechanisms, while also anchoring it to known effects at organism level (i.e., reproduction). Results showed that the photoactivity of TiO2 (UV exposed) played a major role in enhancing TiO2 toxicity, activating transcription of oxidative stress, lysosome damage and apoptosis mechanisms. For non-UV activated TiO2, where toxicity at organism level (reproduction) was lower, results showed the potential for long-term effects (i.e., mutagenic and epigenetic). NM specific mechanisms were identified: NM103 affected transcription and translation, NM104_UV negatively affected reproductive system/organs; and NM105_UV activated superoxide anion response. Results provided mechanistic information for UV-related phototoxicity of TiO2 materials and evidences of the potential long-term effects.
Project description:The effect of nanomaterials (NMs) is less understood in light of the implemented and existing methodologies for regular chemicals. To understand the mode of action of NMs is one of the alternatives to improve predictions and environmental risk assessment (ERA). In the present work the high-throughput gene expression tool (4x44K microarray for Enchytraeus crypticus) was used to investigate the mechanisms activated by Ni exposure. Ni nanoparticles (Ni-NPs) were investigated together with Ni-salt (NiNO3). Testing was done based on reproduction effect concentrations (EC20, EC50) using 3 and 7 days exposure periods.
Project description:The testing of NMs under the currently available standard toxicity tests does not cover many of the NMs specificities. One of the current recommended approaches forward lays on understanding the mechanisms of action as these can help predicting long term effects and safe-by-design production. Copper nanomaterials (Cu-NMs) usage has been highly increasing with the concern in terms of exposure, effect and associated risks. In the present study we used the high-throughput gene expression tool developed for Enchytraeus crypticus (44Kx4 Agilent microarray) to study to the effect of exposure to several copper forms. The copper treatments include two NMs (spherical and wires) and two copper-salt treatments (CuNO3 spiked and Cu field historical contamination). Testing was done based on reproduction effect concentrations (EC20, EC50) using 3 and 7 days exposure periods.
Project description:Negatives effects induced by exposure to ultra-violet (UV) radiation are well known. Nevertheless the modes of action of UV radiation are not well understood, in particular in soil invertebrates. In the present work, the effects of two UV doses (mimicking worst case scenarios in earth crust) on gene expression profile of Enchytraeus crypticus (Enchytraeidae, Oligochaeta) were investigated using the high-throughput 4 x 44K microarray developed for the species.
Project description:Zinc (Zn) is known to be relatively toxic to some soil-living invertebrates including the ecologically important enchytraeid worms. To reveal the molecular mechanisms of zinc toxicity we assessed the gene expression profile of Enchytraeus crypticus (Enchytraeidae), exposed to the reproduction effect concentrations EC10 and EC50, over 4 consecutive days, using a high-throughput microarray (species customized). Three main mechanisms of toxicity to Zn were observed: 1) Zn trafficking (upregulation of zinc transporters, a defence response to regulate the cellular zinc level), 2) oxidative stress (variety of defence mechanisms, triggered by Reactive Oxygen Species (ROS) generated by Zn), and 3) effects on the nervous system (possibly the primary lesion explaining the avoidance behaviour and also why enchytraeids are relatively susceptible to Zn). The adverse outcome at the organism level (reproduction EC50) could be predicted based on gene expression (male gonad development, oocyte maturation), with Zn at the EC50 affecting processes related to higher stress levels. The gene expression response was time-specific and reflected the cascade of events taking place over-time. The 1 to 4 days of exposure design was a good strategy to capture the sequence of events towards zinc adverse outcomes in E. crypticus.
Project description:Transcriptome assembly and microarray construction for Enchytraeus crypticus, a model oligochaete to assess stress response mechanisms derived from soil conditions
