Juvenile African Clawed Frogs ( Xenopus laevis ) Express Growth, Metamorphosis, Mortality, Gene Expression, and Metabolic Changes When Exposed to Thiamethoxam and Clothianidin

Neonicotinoids (NEO) represent the main class of insecticides currently in use, with thiamethoxam (THX) and clothianidin (CLO) primarily applied agriculturally. With few comprehensive studies having been performed with non-target amphibians, the aim was to investigate potential biomarker responses a...

Full description

Saved in:

Bibliographic Details
Published in:	International journal of molecular sciences Vol. 22; no. 24; p. 13291
Main Authors:	Jenkins, Jill A, Hartop, Katherine R, Bukhari, Ghadeer, Howton, Debra E, Smalling, Kelly L, Mize, Scott V, Hladik, Michelle L, Johnson, Darren, Draugelis-Dale, Rassa O, Brown, Bonnie L
Format:	Journal Article
Language:	English
Published:	Switzerland MDPI AG 10-12-2021 MDPI
Subjects:	Animals Biomarkers Brain - drug effects Brain - metabolism Cytochrome Cytology Cytotoxicity Decontamination Enzymatic activity Enzyme activity Enzymes Exposure Flow cytometry Frogs Gene Expression Guanidines - pharmacology Guanidines - toxicity Hepatocytes Hierarchies Insecticides Juveniles Laboratories Liver Liver - drug effects Liver - enzymology Liver - metabolism liver enzymes Metabolism Metabolites Metamorphosis Metamorphosis, Biological Morphology Mortality neonicotinoids Neonicotinoids - pharmacology Neonicotinoids - toxicity Neurotoxicity Oxidoreductases - analysis Pesticides Reductases Reptiles & amphibians Sperm Structure-function relationships Thiamethoxam Thiamethoxam - pharmacology Thiamethoxam - toxicity Thiazoles - pharmacology Thiazoles - toxicity Transcription Xenopus laevis Xenopus laevis - genetics Xenopus laevis - metabolism Xenopus laevis biomarkers neonicotinoids liver enzymes flow cytometry metamorphosis gene expression
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	Neonicotinoids (NEO) represent the main class of insecticides currently in use, with thiamethoxam (THX) and clothianidin (CLO) primarily applied agriculturally. With few comprehensive studies having been performed with non-target amphibians, the aim was to investigate potential biomarker responses along an adverse outcome pathway of NEO exposure, whereby data were collected on multiple biological hierarchies. Juvenile African clawed frogs, , were exposed to commercial formulations of THX and CLO at high (100 ppm) and low (20 ppm) concentrations of the active ingredient. Mortality, growth, development, liver metabolic enzyme activity, and gene expression endpoints were quantified. Tadpoles ( > 1000) from NF 47 through tail resorption stage (NF 66) were exposed to NEO or to NEO-free media treatments. Liver cell reductase activity and cytotoxicity were quantified by flow cytometry. Compared to control reference gene expressions, levels of expression for NEO receptor subunits, cell structure, function, and decontamination processes were measured by RT-qPCR by using liver and brain. Mortality in THX high was 21.5% compared to the control (9.1%); the metabolic conversion of THX to CLO may explain these results. The NF 57 control tadpoles were heavier, longer, and more developed than the others. The progression of development from NF 57-66 was reduced by THX low, and weight gain was impaired. Liver reductases were highest in the control (84.1%), with low NEO exhibiting the greatest reductions; the greatest cytotoxicity was seen with THX high. More transcriptional activity was noted in brains than in livers. Results affirm the utility of a study approach that considers multiple complexities in ecotoxicological studies with non-target amphibians, underscoring the need for simultaneously considering NEO concentration-response relationships with both whole-organism and biomarker endpoints.
Bibliography:	Department of Biological Sciences, Science and Arts College, King Abdulaziz University, Rabigh 25732, Saudi Arabia. Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA.
ISSN:	1422-0067 1661-6596 1422-0067
DOI:	10.3390/ijms222413291