HIGH THROUGHPUT (RNA-SEQ) SCREENING FOR BIOMARKERS OF AZINPHOS METHYL (AZM) EXPOSURE IN Rhinella arenarum.

MARDIROSIAN, M; CESCHIN, DG; PIRES, N; LASCANO, C; VENTURINO, A

Natal

Congreso; 9th Congress of Toxicology in Developing Countries and XIX Congresso Brasileiro de Toxicología.; 2015

Sociedaide Brasileira de Toxicologia

Introduction: Azinphos methyl (AZM) is the main organophosphate pesticide applied in Río Negro-Neuquén valley in Argentina. In this sense, it is necessary to control the levels of residues and environmental impact of pesticides. Traditional ecotoxicological biomarkers like reduced glutathione (GSH) levels and the activities of Glutathione S transferase (GST) and Catalase (CAT) are commonly used for biomonitoring. However, they may fail for sensitivity and unspecifically response to oxidative stress. Native species are a preferred resource for its ecological significance. In this sense, we have evaluated pesticide effects on common toad R. arenarum larvae. In this work, we screen for molecular biomarkers using RNA-Seq technology and compare the response with traditional biomarkers, in order to develop new specific and sensitive biomarkers.Objective: To develop new early, specific, sensitive biomarkers to AZM exposure.Materials and Methods: R. arenarum embryos were obtained by in vitro fertilization. Larvae (complete operculum stage + 11 days) were exposed to sublethal concentration of AZM (0.5 mg/L) [96h-LC50 10 mg/L)]. Samples were taken at 6h and 24h to evaluate GSH levels and the activities of GST and CAT. At the same time, samples were collected for RNA purification and massive sequencing.Results and discussion: We could detect changes only in GSH content but not in GST or CAT activities after 6h and 24h exposures to AZM. Regarding to the transcriptomic profile, we could determine up- and down-regulated genes compared with control for both 6h and 24h of exposure. After gene enrichment analysis, over representation of detoxification and oxidative stress pathways was found. Moreover, for Gene Ontology classification there were hits for Biological Process category such as cell differentiation, developmental growth, catabolic and hormone metabolic process, cell proliferation and cell cycle.