Project description:Due to its antimicrobial activity, silver nanoparticles (Ag-NPs) are among the most used NPs worldwide, yet little information is available regarding their effects, particularly in soil dwelling organisms. Enchytraeids (Oligochaeta) are important members of the soil fauna which actively contribute to the acceleration of organic matter decomposition and nutrient recycling processes. Hence, for hazard and risk assessment it is important to provide toxicity data for these organisms and to understand more in regard to the mode of action of Ag-NPs within organism. To study this we conducted toxicity experiments using the OECD standard guideline, testing Ag-NPs and AgNO3, having assessed survival, reproduction and differential gene expression. Population toxicity responses were assessed showing higher toxicity for the AgNO3. In an attempt to understand the mode of action we performed transcription profiling using the microarray. Gene expression profile of Enchytraeus albidus was analysed after 2 days of exposure to 100 and 200 mg/kg of two silver forms (nanoparticles and salt_silver nitrate) in OECD soil. Three biological replicates per test treatment and control (clean OECD soil) were used.
Project description:Transcriptional responses in Enchytraeus albidus (Oligochaeta): comparison between cadmium and zinc exposure and linkage to reproduction effects
Project description:Effect of Cu-Nanoparticles versus Cu-salt in Enchytraeus albidus (Oligochaeta): differential gene expression through microarray analysis
Project description:Background: Molecular mechanisms of response to pesticides are scarce and information on such responses from soil invertebrates is almost inexistent. Enchytraeus albidus (Oligochaeta) is a standard soil ecotoxicology model species for which effects of many pesticides are known on survival, reproduction and avoidance behaviour. With the recent microarray development additional information can be retrieved on the molecular effects. Methodology/Principal Findings: Experiments were performed to investigate the transcription responses of E. albidus when exposed to three pesticides – dimethoate (insecticide), atrazine (herbicide) and carbendazim (fungicide) – in a range of concentrations that inhibited reproduction by 10%, 20%, 50% and 90% (EC10, EC20, EC50 and EC90, respectively). The goal of this study was to further identify key biological processes affected by each compound and if dose-related. All three pesticides significantly affected biological processes like translation, regulation of the cell cycle or general response to stress. Intracellular signalling and microtubule-based movement were affected by dimethoate and carbendazim whereas atrazine affected lipid and steroid metabolism (also by dimethoate) or carbohydrate metabolism (also by carbendazim). Response to DNA damage/DNA repair was exclusively affected by carbendazim. Conclusions: Changes in gene expression were significantly altered after 2 days of exposure in a dose-related manner. The mechanisms of response were comparable with the ones for mammals, suggesting across species conserved modes of action. The present results indicate the potential of using gene expression in risk assessment and the advantage as early markers.
Project description:Background: Molecular mechanisms of response to pesticides are scarce and information on such responses from soil invertebrates is almost inexistent. Enchytraeus albidus (Oligochaeta) is a standard soil ecotoxicology model species for which effects of many pesticides are known on survival, reproduction and avoidance behaviour. With the recent microarray development additional information can be retrieved on the molecular effects. Methodology/Principal Findings: Experiments were performed to investigate the transcription responses of E. albidus when exposed to three pesticides M-bM-^@M-^S dimethoate (insecticide), atrazine (herbicide) and carbendazim (fungicide) M-bM-^@M-^S in a range of concentrations that inhibited reproduction by 10%, 20%, 50% and 90% (EC10, EC20, EC50 and EC90, respectively). The goal of this study was to further identify key biological processes affected by each compound and if dose-related. All three pesticides significantly affected biological processes like translation, regulation of the cell cycle or general response to stress. Intracellular signalling and microtubule-based movement were affected by dimethoate and carbendazim whereas atrazine affected lipid and steroid metabolism (also by dimethoate) or carbohydrate metabolism (also by carbendazim). Response to DNA damage/DNA repair was exclusively affected by carbendazim. Conclusions: Changes in gene expression were significantly altered after 2 days of exposure in a dose-related manner. The mechanisms of response were comparable with the ones for mammals, suggesting across species conserved modes of action. The present results indicate the potential of using gene expression in risk assessment and the advantage as early markers. Gene expression in E.albidus was measured at 2 days after exposure to dimethoate, atrazine and carbendazim at 4 concentrations of effect on reprocduction (EC10, EC20, EC50 and EC90). Three biological replicates per treatment were used.
Project description:Metals, including copper (Cu) and nickel (Ni) are among the most common contaminants in soils in Europe. Although their effects are relatively well known regarding survival and reproduction of soil invertebrates, their modes of action in these organisms are still poorly studied. Enchytraeus albidus has been used in soil ecotoxicology for many years, and more recently has a gene library and an oligonucleotide microarray for this species which allowed gene expression studies. This has potentiated the means to study further in depth the mechanisms of response to stressors. The main aim of this study is to understand the mechanisms of response of E. albidus to Cu and Ni. For that we have 1) assessed and compared the transcriptomic profile of E. albidus in response to Cu and Ni and 2) compared the Cu, Ni, Cd and Zn transcriptomic profiles. For the microarray hybridizations, E. albidus were exposed to the reproduction effect concentrations EC50 and EC90 of Cu and Ni during 4 days. Results indicate that Cu and Ni have to some extent, similar mechanisms of toxicity and that have already been identified in other species, indicating cross-species conserved mechanisms. Based on hierarchical clustering, it was possible to observe a clear separation of Cd treatments from all other metals. This separation strongly correlates with the available information regarding the toxicokinetics of the tested metals, in which Ni shows properties similar to essential metals.