Project
TFM toxicity in planaria: opportunity for validation of a surrogate species for rapid TFM toxicity testing
Planaria (Dugesia dorotocephala) is a type of brown flatworm that is easily cultured in the laboratory, in a static system at room temperature; it is found in Canadian freshwaters and readily responds to chemical exposure. Recent studies have proposed this flatworm as a model organism for conducting rapid toxicity testing using a variety of compounds, from pesticides to pharmaceuticals. Due to the small nature of the worms, ease of maintenance and rapid response to chemicals, they could be a promising model for range finder tests and rapid lampricide toxicity testing in the laboratory and in the field. However, we first need to understand how they respond to TFM and whether the mode of action of the lampricide is the same in this species as it is in fishes. Therefore, my pilot proposal will investigate the toxicity of TFM in planaria, whether abiotic factors (pH and alkalinity) impact it to the same degree as in the lampreys and what the mode of action of TFM is in planaria. We have preliminary data, where we conducted toxicity testing at an alkalinity of both 80 (pH 8.5-8.7) and 120 (pH ~7.5) mg/L CaCO3, suggesting that alkalinity reduces TFM toxicity much like it does in sea lampreys. These findings look promising, as planaria appear to give relevant information within 2.0-2.5h, compared to 12-24h for the larval sea lampreys. If my research group can validate the planaria as a surrogate organism for TFM toxicity, it will offer the opportunity to rapidly conduct toxicity testing in both the laboratory and in the field, at different water chemistries, over a much shorter time (2.0-2.5h). I hypothesize that the toxicity of TFM in planaria is impacted by water chemistry (alkalinity and pH) and that TFM impacts energy reserves in planaria, much like it does in sea lampreys and non-target fishes.