Project 4 – Neurobehavioral and Bioenergetic Consequences of Evolving Resistance to Polycyclic Aromatic Hydrocarbons in a Multi-Stressor Environment

Project Leaders

Objective and Importance of Research

Evolved resistance to hazardous contaminants has far reaching implications for environmental health, ecological risk assessment, and management and remediation of contaminated sites. However, key knowledge gaps exist in the understanding of the mechanisms of pollution adaptation and fitness consequences, especially when animals are exposed to multiple chemicals. This project will study how polycyclic aromatic hydrocarbons (PAHs) and metals may interact to impact the fitness of Atlantic killifish, how the gut microbiome may affect resistance to PAHs, and how the toxicity analyses of real-world exposures can inform ecological risk assessments.

Summary

The overarching goal of the Center is to determine later life consequences of early life co-exposure to polycyclic aromatic hydrocarbons (PAHs) and heavy metals. This project addresses ecological outcomes of PAH and metal exposure in an evolutionary toxicology context.

Evolved resistance to hazardous contaminants has far reaching implications for environmental health, ecological risk assessment, and management. However, key knowledge gaps exist in the understanding of the mechanisms of pollution adaptation and fitness consequences, especially when animals are exposed to multiple chemicals (simultaneous or sequential) and other abiotic stressors in their natural environment. To address these gaps, Project 4 will build on extensive previous research on evolved resistance to PAHs in Atlantic killifish (Fundulus heteroclitus) in the Elizabeth River, VA. Specifically, researchers will elucidate the role of mitochondria as an important target of PAHs and metals during early development in mediating adverse behavioral and bioenergetic outcomes later in life and in subsequent generations under optimal and suboptimal thermal and dissolved oxygen conditions.

Overall, studies elucidate ecologically relevant fitness outcomes of PAH and metal exposures and selected aspects of underlying molecular mechanisms in killifish populations, while rendering the toxicity assays for characterizing effectiveness of remediation. Novel areas of research include elucidating PAH and metal interactive effects, discerning the role of the gut microbiome in PAH resistance, and developing an ecologically relevant toxicity analyses based on killifish behavior and energetics to inform ecological risk assessment.

Project Aims

  1. Determine later life fitness consequences of early life simultaneous exposures to PAHs and cadmium (Cd) and lead (Pb).
  2. Elucidate later life and cross generational fitness consequences of developmental exposures to PAHs and subsequent Cd or Pb exposure and determine links to epigenetic modifications.
  3. Compare the gut microbiome differences in PAH-resistant and sensitive fish, and elucidate the potential contributions of the gut microbiome on PAH resistance using germ-free killifish studies.
  4. To develop an ecological-effect directed analysis based on medium-throughput mitochondrial and behavioral assays to assess toxicity of environmental samples including remediated samples derived from Project 5.