Molecular and biochemical characterization of biotransformation systems and antioxidant defenses associated with hypoxia support and relationship with contaminated environments adaptation

Abstract

The turtles represents a vertebrate group with hypoxia tolerance, surviving to lack of oxygen for prolonged periods, however, no information about the oxidative damage control when there are elements in the environment that can modify the activity of systems associated with the detoxification and antioxidant defense, such as those generated by environmental contamination. Phrynops geoffroanus is a freshwater turtle easily found in sites contaminated primarily by chemical and organic compounds. The evaluation of enzymatic activity of antioxidants and biomarkers in animals of environmental contamination indicate that protection of oxidative damage can contribute to the species adaptation to pollution. Therefore, the aim of this study is to evaluate the transcriptional response and catalytic systems of biotransformation and antioxidant systems in P. geoffroanus exposed to chemical and organic pollutants in hypoxia and normoxia conditions, in order to establish whether the protection mechanisms for oxidative damage generated by hypoxia are responsible for the carrying capacity of these animals to environmental contamination. For this, we will: 1) characterize the key genes associated with GSH production and hypoxia response, 2) evaluate the expression of these genes in major tissues responsive to the presence of contaminants, 3) analyze the enzymatic activity of the main elements of the detoxification in order to ascertain, associated with expression data, the hypothesis that extremely high antioxidant capacity of these animals is the key element to assist in the ability to support highly contaminated environments. Thus, it is expected: i) generate novel molecular data about the genes evaluated, ii) help in understanding the mode of contaminants action and the mechanisms of response to the presence of xenobiotics; iii) identify the relationship of these effects on the condition control of the radicals generated by the diving behavior and prolonged absence of O2. All information generated will be original and relevant to understanding the biology, biochemistry and evolution of species and related species.