Focused transcriptomics arrays (EcoToxChips) to characterize the molecular toxicity pathways and transcriptomics points of departures (tPODs) of mixtures in native fish

Funding period: 2024-2029
Lead: Gerald Tetreault
Total GRDI funding: $164,396

Traditional risk assessments rely on animal testing or wild fish collections to determine the toxicity of contaminants. The ‘Fish Embryo Toxicity (FET) Tests Using Tissue Culture Plates' test covers sensitive stages of fish development (embryo-development and hatching) (OECD, 2013). The test utilizes a static-renewal procedure, and benefits from the space-saving design of plates. This allows sufficient replication and sufficient numbers of eggs per replicate for statistical robustness. The test provides vital information on effects in a relevant Canadian test-species. It covers sensitive stages of development and assesses environmentally-relevant endpoints (embryonic survival, hatching, length at hatch and deformities at hatch), that can be used in environmental risk assessments. A new approach is to combine FET with new molecular toxicology approaches that have been in development and are beginning to make significant contributions to the impact of contaminants on aquatic biota. However, the link between ‘omic responses and higher-level apical impacts often retards the adoption of these new approaches. Recent development of a reduce transcriptomic assay (EcoToxChip) will be used to tests the effects of complex mixtures of contaminants measured in matrix from the SWAPIT - ICMP programs, on the expression of relevant genes using the Fathead minnow and Rainbow trout ExoToxChip. Specifically, EcoToxChip will be run to determine if toxicogenomics can be used as an effect-based monitoring approach for fish exposed to contaminant-abiotic stressors (i.e., mixtures; cumulative stressors).