Combined effects of temperature and clomazone (Gamit®) on oxidative stress responses and B-esterase activity of Physalaemus nattereri (Leiuperidae) and Rhinella schneideri (Bufonidae) tadpoles

Abstract

Temperature is an important factor influencing the toxicity of chemicals in aquatic environments. Neotropical tadpoles experience large temperature fluctuations in their habitats and many species are distributed in areas impacted by agriculture. This study evaluated the effects caused by the exposure to clomazone (Gamit) at different temperatures (28, 32 and 36 °C) on biochemical stress responses and esterase activities in Physalaemus nattereri and Rhinella schneideri tadpoles. Results evidenced that temperature modulates the effects of clomazone on biochemical response of tadpoles. Antioxidant enzymes, including catalase, superoxide dismutase (SOD), and glucose-6-phosphate dehydrogenase had their activities increased by clomazone in P. nattereri treated at higher temperatures. The biotransformation enzyme glutathione-S-transferase (GST) was also induced by clomazone at 32 and 36 °C. In R. schneideri, clomazone failed to alter antioxidant enzymes at 28 °C, but SOD and GST were increased by clomazone at higher temperatures after three days. All enzymes had their activities returned to the control levels after eight days in R. schneideri. Lipid peroxidation was induced in both species exposed to clomazone at 32 and 36 °C, but not at 28 °C. Acetylcholinesterase was not sensitive to clomazone and temperature, while most treatments impaired carboxylesterase activity. Integrated biomarker response (IBR) was notably induced by temperature in both species, and a synergic effect of temperature and clomazone was mostly observed after three days of exposure. These findings imply that tadpoles from tropical areas may present differential responses in their physiological mechanism linked to antioxidant defense to deal with temperature fluctuations and agrochemicals presence in their habitats.

First evaluation of novel potential synergistic effects of glyphosate and arsenic mixture on Rhinella arenarum (Anura: Bufonidae) tadpoles

“…AChE (a neural enzyme that catalyzes the hydrolysis of the neurotransmitter acetylcholine in the nervous system of animals) is a useful biomarker that has been used in studies of amphibian tadpoles exposed to pesticides (Freitas et al., 2017). In agreement with this, the NOEC 48-h of GBH increased AChE activity compared to controls.…”

Combined effects of heatwaves and micropollutants on freshwater ecosystems: Towards an integrated assessment of extreme events in multiple stressors research

“…A GST rise indicates an increased oxidative stress, which may lead to a reduced fitness of amphibians (Gripp et al, 2017 ). Such an increase was not observed at the same herbicide concentrations at lower temperature (Freitas et al, 2017 ). The HW treatment alone indicated no significant difference in the activity of this phase II detoxification enzyme.…”

“…The thermometer symbol indicates an effect related to temperature only, whereas the symbols of the thermometer and of the chemical together indicate a combined effect. (1) Freitas et al ( 2016 ), (2) Park et al ( 2020 ), (3) Mehdi et al ( 2019 ), (4) Freitas et al ( 2017 ), (5) Prophete et al ( 2006 ), (6) Gripp et al ( 2017 ), (7) Birnie‐Gauvin et al ( 2017 ), and (8) Hani et al ( 2019 )…”

Bisphenol F Disrupts Thyroid Hormone Signaling and Postembryonic Development in Xenopus laevis

“…Integrated biomarker response (IBR) is a good method to summarize multi biomarker responses into one general index. , Following the method developed by Sanchez et al, we calculated the IBR indexes for TH-response gene transcription, gross morphology and Notch-related gene transcription in the T3-induced metamorphosis assay, with the IBR indexes for TH-response gene transcription in tails cultured in vitro . Samples from the control group were considered as the reference for the IBR indexes of TH-response gene transcription and Notch-related gene transcription.…”