New insights about the toxicity of 2,4-D: Gene expression analysis reveals modulation on several subcellular responses in Chironomus riparius.

Autor: Pinto TJDS; PPG-SEA and NEEA/CRHEA/SHS, São Carlos Engineering School, University of São Paulo, Brazil; University of Campinas (UNICAMP), Institute of Chemistry, Campinas, São Paulo, Brazil. Electronic address: thandyjuniosilva@gmail.com., Martínez-Guitarte JL; Department of Physics, Mathematics, and Fluids, National Distance Education University (UNED), Madrid, Spain., Dias MA; University of Campinas (UNICAMP), Institute of Chemistry, Campinas, São Paulo, Brazil., Montagner CC; University of Campinas (UNICAMP), Institute of Chemistry, Campinas, São Paulo, Brazil., Espindola ELG; PPG-SEA and NEEA/CRHEA/SHS, São Carlos Engineering School, University of São Paulo, Brazil., Muñiz-González AB; Department of Physics, Mathematics, and Fluids, National Distance Education University (UNED), Madrid, Spain.
Jazyk: angličtina
Zdroj: Pesticide biochemistry and physiology [Pestic Biochem Physiol] 2024 Sep; Vol. 204, pp. 106088. Date of Electronic Publication: 2024 Aug 18.
DOI: 10.1016/j.pestbp.2024.106088
Abstrakt: Herbicides are the main class of pesticides applied in crops and are capable of polluting the surrounding freshwater system; thus, understanding their impact on non-target species, whose mechanism of action is not described, helps to elucidate the real risks of these pollutants to the environment. 2,4-dichlorophenoxyacetic acid (2,4-D) is frequently detected in water and, due to its persistence, poses a risk to wildlife. In this way, the present work aimed to describe the implication of exposure to concentrations of 2,4-D already reported in aquatic environments in several physiological mechanisms of C. riparius at molecular and biochemical levels. To achieve this, bioassays were conducted with fourth instar larvae exposed to three concentrations of 2,4-D (0.1, 1.0, and 7.5 μg L -1 ). Larvae were collected after 24 and 96 h of exposure, and the expression of 42 genes, related to six subcellular mechanisms, was assessed by Real-Time PCR (RT-PCR). Besides, the activity of the enzymes catalase (CAT), glutathione S-transferase (GST), and acetylcholinesterase (AChE) was determined. The main metabolic route altered after exposure to 2,4-D was the endocrine system (mainly related to 20-hydroxyecdysone and juvenile hormone), confirming its endocrine disruptor potential. Four of the eleven stress response genes studied were down-regulated, and later exposure modulated DNA-repair genes suggesting genotoxic capacity. Moreover, only one gene from each detoxification phase was modulated at short exposure to 1.0 μg L -1 . The molecular responses were not dose-dependent, and some early responses were not preserved after 96 h, indicating a transient response to the herbicide. Exposure to 2,4-D did not alter the activity of CAT, GST, and AChE enzymes. The responses described in this study reveal new mechanistic pathways of toxicity for 2,4-D in non-target organisms and highlight potential ecological consequences for chironomids in aquatic systems at the edges of agricultural fields.
Competing Interests: Declaration of competing interest none.
(Copyright © 2024 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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