PI: Thiago Parente (Universidade Federal do Rio de Janeiro)
U.S. Partner: Mark Hahn (Woods Hole Oceanographic Institution)
Project Dates: September 2013 to July 2015
CYP1 enzymes are responsible for the biotransformation of natural compounds and anthropogenic pollutants. Usually the reactions catalyzed by CYP1 enzymes lead to detoxification, when the compound is eliminated from the body without causing harm. CYP1 enzymes, however, are also known to catalyze bioactivation reactions, in which one of the reaction products is more toxic than its parent compound. The equilibrium between the detoxification (beneficial) and bioactivation (detrimental) roles of CYP1 enzymes has been fine tuned for each and every vertebrate species over the course of evolution. This PEER Science project is closely aligned with the National Science Foundation-supported work of the U.S. partner, Dr. Mark Hahn, as both involve the study of different naturally evolved and selected solutions for the same issue: the balance between detoxification and bioactivation by CYP1 enzymes using fish species as vertebrate models. The adaptation of Killifish (studied by Dr. Hahn) is a well documented event classified as dramatic, rapid, convergent, and triggered by anthropogenic pollutants that balance the dual role of CYP1 enzymes at the gene expression level. However, the adaptation of Loricariidae fish is poorly known and most probably can have the opposite classification: gradual, slow, divergent, and triggered by chemicals naturally present in the fish microhabitat. The goals of this project are to determine whether the adaptations of CYP1 enzymes in Loricariidae fishes are convergent or divergent and how they change the susceptibility of this species to the toxic effects of petrogenic compounds.
Dr. Parente and his research team will sequence the CYP1 genes of 100 Loricariidae species from the Amazon, and these gene sequences will be used to determine the enzyme sequences, which in turn will be aligned and compared for amino acids substitutions and interaction with classical CYP1 substrates. Selected Loricariidae species will be used for biological assays to evaluate the toxic effects of petrogenic derivates and their molecular mechanisms of action. Due to the current and future prospects for crude oil drilling activities in the Amazon region, it is imperative to understand the metabolism of petrogenic hydrocarbons by Amazonian biota. This is especially true in the case of Loricariidae fishes, as it is already known that those species have CYP1 enzymes with distinct affinity for substrates. It needs to be determined whether these changes will unbalance the evolved equilibrium of CYP1 dual roles to the beneficial or to the detrimental side. This knowledge will be crucial to better evaluate the risks of oil drilling activities for Amazonian biodiversity.
Link to Project Blog