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EnvironOme Overview

 

Ecotoxicoproteomics and ecotoxicogenomics are powerful tools to spot early molecular events involved in toxicant responses which are responsible for the adverse effects observed at higher levels of biological organization. Knowledge of the phenotypic consequences of stress must be accompanied by information on the molecular determinants (genes) that are induced or suppressed as well as the type and level of expression of their products (proteins). Taken together, phenotype and molecular data will help not only to unravel the mode of action (MoA) of the stressor but also which components might be affecting the survival, growth, and reproduction of a given species, which may ultimately impact the population and the community.

Effects studied in classical ecotoxicology tests can be considered as a final result of the cumulative molecular and cellular level effects. Nevertheless, these endpoints are complex and therefore difficult to correlate to a particular toxicant. On the other hand it is accepted that toxicity can be assessed at the sub-cellular level earlier than it is observed at higher levels of biological organization.

Proteomics and transcriptomics share the characteristic of being "not hypothesis-driven". These two approaches used on the same samples will provide complementary data: while proteomics assesses the functional units of cells but might be compromised by an extremely large dynamic range of proteins within cells and by the difficulty of protein sequencing, genomics has the advantage of being able to detect very small amounts of RNA. Furthermore, transcriptome sequencing are routine techniques, easily available allowing a high-throughput analysis. Nevertheless, while mRNAs can serve as effectors of some biological functions, proteins are the functional units responsible for most biological functions, which in turn, are determinant for organisms' fitness.

Environmental Risk Assessment (ERA) may be complex to assess, particularly in cases where multiple exposures can happen, especially when assessing the toxic potential of contaminated sites. In this context in situ tests have a promising potential. The data gathered on these types of bioassays does not require prior knowledge of the type or the concentrations of chemicals present in the soil. Moreover it allows the assessment of toxicity of complex mixtures and integrates the effects of exposure time and exposure conditions. As such, they have the advantages of laboratory assays without the need for extrapolation to effects in the field. These traits make them a promising and robust diagnostic approach to assess toxic effects to soil organisms.

Within Environome, efforts will be addressed to improve the knowledge on the link between individual responses and molecular responses (proteins and genes) to stressors. This way we will get the hold of the continuum of biological response. Moreover, at the end of this project we expect to have a better understanding of toxicants pathways of toxicity and to have developed and validated a set of effective molecular tools (proteomics and transcriptomics) to assess the effects of pesticides in edaphic invertebrates, and transpose them to field exposure bioassay scenarios (a major asset for ERA).

F. candida is a common and widespread arthropod that occurs in soils throughout the world and has been used as a "standard" test organism for more than 40 years for estimating the effects of pesticides and environmental pollutants on non-target soil arthropods. We will combine individual and population level responses, using acute and chronic tests, with transcriptional of organisms as well as proteomic analysis of subcellular fractions of the organisms.

With this approach we expect to decipher the early molecular events involved in toxicant responses responsible for the adverse effects observed at higher levels of organization. The use of only one technology does not suffice for gaining a comprehensive understanding of any physiological pathway in an organism.


An integrated approach is mandatory to tackle this issue: a mixed team of senior, junior and trainee scientists with expertise on ecotoxicology, namely in the development of laboratory and in situ bioassays, in the validation of alternative methods in toxicology and ecotoxicology and linking different levels of biological organization with researchers with a large background on proteomics and transcriptomics approaches. The collaboration of GIRM and IMAR (Portugal) with L-ProBE from Ghent University (Belgium) and VU Amsterdam (The Netherlands) and the private company ECT Oekotoxikologie GmbH (Germany) allows us to strength the foundations of ecotoxicoproteomics and ecotoxicogenomics, a mechanistic and holistic approach, not yet fully explored, but with expected significant impacts in several research fields in environmental sciences and regulatory agencies.