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A Systems-Level Approach to Characterizing Effects of ENMs in Terrestrial Organisms and Ecosystems
Rico, C., M. Johnson, J. Reichman, AND C. Andersen. A Systems-Level Approach to Characterizing Effects of ENMs in Terrestrial Organisms and Ecosystems. 253rd American Chemical Society National Meeting and Exposition, San Francisco, CA, April 02 - 06, 2017.
Regulatory agencies are faced with challenges of developing new standard protocols and laboratory practices to assess environmental implications of engineered nanomaterials (ENMs). In response to these challenges, WED scientists adopted a systems-level approach for evaluating the uptake and toxic potential of ENMs in whole organisms. This approach uses complementary analytical tools to explore how molecular changes can be linked with whole-organism responses, and affect important ecosystem processes. We performed full life cycle experiments by exposing Arabidopsis thaliana and wheat to cerium oxide nanoparticles. Our results demonstrated changes in nitrogen uptake and/or use and carry-over effects in offspring of plants whose parents were exposed to ENMs. These findings suggest that the system-level approach could be useful in providing a more complete assessment of ENM toxicity in whole organisms. Contact: Cyren Rico, 541-754-4632. This presentation contributes to CSS 18.02
Engineered nanomaterials (ENMs) represent a new regulatory challenge because of their unique properties and their potential to interact with ecological organisms at various developmental stages, in numerous environmental compartments. Traditional toxicity tests have proven to be unreliable due to their short-term nature and the subtle responses often observed following ENM exposure. In order to fully assess the potential for various ENMs to affect responses in organisms and ecosystems, we are using a systems-level framework to link molecular initiating events with changes in whole-organism responses, and to identify how these changes may translate across scales to disrupt important ecosystem processes. This framework utilizes information from nanoparticle characteristics and exposures to help make linkages across scales. We have used Arabidopsis thaliana as a model organism to identify potential transcriptome changes in response to specific ENMs. In addition, we have focused on plant species of agronomic importance to follow multi-generational changes in physiology and phenology, as well as epigenetic markers to identify possible mechanisms of inheritance. We are employing and developing complementary analytical tools (plasma-based and synchrotron spectroscopies, microscopy, and molecular and stable-isotopic techniques) to follow movement of ENMs and ENM products in plants as they develop. These studies have revealed that changes in gene expression do not always translate into changes in growth and development of whole organisms, but that subtle down-stream events often occur following ENM exposure. For example, exposure to nCeO2 alters nitrogen uptake and use in wheat, and alters nutrition and growth in offspring of plants whose parents were exposed to ENMs. Collectively, this multi-scale, system-level approach will help us identify early changes in response to ENM exposure that translate to changes in whole organisms, and how changes in whole organisms may affect other ecosystem processes at scales relevant to risk assessment.