Project description:Polycyclic Aromatic Hydrocarbons (PAHs) continue to cause environmental challenges due to their release in the environment by a great variety of anthropogenic activities and their accumulation in soil ecosystems. Here we studied the toxicological effect of the model PAH phenanthrene (Phe) on the soil invertebrate model Enchytraeus crypticus at the individual, tissue and molecular level. Organisms were exposed to Phe for 2 and 21 days to the (previously estimated) EC10 and EC50 (population reproduction over 3 weeks). Gene expression profiling did not reveal a typical Phe-induced biotransfor-mation signature, as it usually does in arthropods and vertebrates. Instead, we observed only general metabolic processes to be affected after 2 days of exposure, such as translation and ATP synthesis-coupled electron transport. Histological sections of tissues of 2-day exposed animals did not show any deviations from the control situation. In contrast, prolonged exposure up to 21 days showed histopathological effects: chloragogenous cells were highly vacuolated and hypertrophic. This was corroborated by differential expression of genes related to immune response and oxidative stress at the transcriptomic level. The data exemplify the complexity and species-specific features of PAH toxicity among soil invertebrate communities, which restricts read-across and extrapolation in the context of soil ecological risk assessment. The data presented in our manuscript is an exposure experiment where E. cryticus is exposed to phenanthrene EC10 and EC50 on reproduction for 2 and 21 days. A single channel, interwoven loop design was used to test animals. 4 biological replicates per condition were used containing 25 grams of soil and 5 - 7, adult old animals per replicate. The platform is a 4*180k Agilent platform containing some 86k E. crypticus probes in duplicate. However, only a subset of the probes (23k) was used for the analysis. To see which probes were used in the analysis see the raw data files control type column, only probes which are denoted with a 0 were used.
Project description:Polycyclic Aromatic Hydrocarbons (PAHs) continue to cause environmental challenges due to their release in the environment by a great variety of anthropogenic activities and their accumulation in soil ecosystems. Here we studied the toxicological effect of the model PAH phenanthrene (Phe) on the soil invertebrate model Enchytraeus crypticus at the individual, tissue and molecular level. Organisms were exposed to Phe for 2 and 21 days to the (previously estimated) EC10 and EC50 (population reproduction over 3 weeks). Gene expression profiling did not reveal a typical Phe-induced biotransfor-mation signature, as it usually does in arthropods and vertebrates. Instead, we observed only general metabolic processes to be affected after 2 days of exposure, such as translation and ATP synthesis-coupled electron transport. Histological sections of tissues of 2-day exposed animals did not show any deviations from the control situation. In contrast, prolonged exposure up to 21 days showed histopathological effects: chloragogenous cells were highly vacuolated and hypertrophic. This was corroborated by differential expression of genes related to immune response and oxidative stress at the transcriptomic level. The data exemplify the complexity and species-specific features of PAH toxicity among soil invertebrate communities, which restricts read-across and extrapolation in the context of soil ecological risk assessment.
Project description:Mechanisms of (photo)toxicity of TiO2 nanomaterials (NM103, NM104, NM105): using high-throughput gene expression in Enchytraeus crypticus
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
Project description:Gene expression can vary with the organisms' life stage. It is known that embryos can be more sensitive to toxicant exposure, as previously demonstrated for Enchytraeus crypticus (Oligochaeta) exposed to cadmium (Cd), known to cause embryotoxicity and hatching delay. It was shown that Ca enters embryos via the L-type Ca channels in the cocoon membrane, this being affected in Cd exposed embryos (Cd-Ca competition is well-known). In the present study, the embryotoxic mechanisms of Cd were studied via high-throughput gene expression for E. crypticus. Cocoons (1e2 days old), instead of the adult organism, were exposed in Cd spiked LUFA 2.2 soil during 1 day. Results showed that Cd affected Ca homeostasis which is implicated in several other molecular processes. Several of the major modulators of Cd toxicity (e.g., impaired gene expression, cell cycle arrest, DNA and mitochondrial damage) were identified in the embryos showing its relevancy as a model in ecotoxicogenomics. The draft Adverse Outcome Pathway was improved. Previously was hypothesized that gene regulation mechanisms were activated to synthesize more Ca channel proteins e this was confirmed here. Further, novel evidences were that, besides the extracellular competition, Cd competes intracellularly which causes a reduction in Ca efflux, and potentiates Cd embryotoxicity.