Understanding the Differences in the Mechanisms of Detoxification Between Invasive and Native Aquatic Animals to Identify New Biocides

Lampricides are used to control sea lamprey in the Great Lakes, are often considered the only successful species-specific biocides to control an invasive fish.   In its development, researchers had to evaluate the toxicity of about 6000 chemicals on various species of fish before identifying its compounds.  This laborious process may be expedited by using an interdisciplinary approach to identifying new biocides.  Improvements in our understanding of the link between genetics and physiological responses to biocides have been made by using modern molecular tools.  For example, rotenone-resistant bighead carp Hypophthalmichthys nobilis responded very differently to a sub-lethal dose of rotenone than a close relative, silver carp Hypophthalmichthys molitrix.   In this study, some detoxification genes and oxidative stress genes were up-regulated in silver carp but were either down-regulated or remained constant in bighead carp, while the proton leak was up-regulated in bighead carp.  Understanding these physiological responses and their resulting metabolic profiles, chemists can explore databases to find chemicals that target specific cellular mechanisms or that can react with the metabolites resulting in increased toxicity of existing biocides.  Researchers can then quickly evaluate these novel biocides using cell-lines that have been developed from tissues of the targeted species.