Juvenile African Clawed Frogs (<i>Xenopus laevis</i>) 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...
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MDPI AG
2021-12-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/22/24/13291 |
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| author | Jill A. Jenkins Katherine R. Hartop Ghadeer Bukhari Debra E. Howton Kelly L. Smalling Scott V. Mize Michelle L. Hladik Darren Johnson Rassa O. Draugelis-Dale Bonnie L. Brown |
| author_facet | Jill A. Jenkins Katherine R. Hartop Ghadeer Bukhari Debra E. Howton Kelly L. Smalling Scott V. Mize Michelle L. Hladik Darren Johnson Rassa O. Draugelis-Dale Bonnie L. Brown |
| author_sort | Jill A. Jenkins |
| collection | DOAJ |
| description | 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, <i>Xenopus laevis</i>, 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 (<i>n</i> > 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. |
| first_indexed | 2024-03-10T03:56:33Z |
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| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T03:56:33Z |
| publishDate | 2021-12-01 |
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| series | International Journal of Molecular Sciences |
| spelling | doaj.art-5ecf838ed89a4d1e8aeea032efa7b6d32023-11-23T08:44:11ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-12-0122241329110.3390/ijms222413291Juvenile African Clawed Frogs (<i>Xenopus laevis</i>) Express Growth, Metamorphosis, Mortality, Gene Expression, and Metabolic Changes When Exposed to Thiamethoxam and ClothianidinJill A. Jenkins0Katherine R. Hartop1Ghadeer Bukhari2Debra E. Howton3Kelly L. Smalling4Scott V. Mize5Michelle L. Hladik6Darren Johnson7Rassa O. Draugelis-Dale8Bonnie L. Brown9U.S. Geological Survey, Wetland and Aquatic Research Center, 700 Cajundome Boulevard, Lafayette, LA 70506, USADepartment of Biology, Virginia Commonwealth University, Richmond, VA 23284, USADepartment of Biology, Virginia Commonwealth University, Richmond, VA 23284, USADepartment of Biology, Virginia Commonwealth University, Richmond, VA 23284, USAU.S. Geological Survey, New Jersey Water Science Center, Lawrenceville, NJ 08648, USAU.S. Geological Survey, Lower Mississippi-Gulf Water Science Center, Baton Rouge, LA 70816, USAU.S. Geological Survey, California Water Science Center, 6000 J Street, Placer Hall, Sacramento, CA 95819, USAU.S. Geological Survey, Wetland and Aquatic Research Center, 700 Cajundome Boulevard, Lafayette, LA 70506, USAU.S. Geological Survey, Wetland and Aquatic Research Center, 700 Cajundome Boulevard, Lafayette, LA 70506, USADepartment of Biology, Virginia Commonwealth University, Richmond, VA 23284, USANeonicotinoids (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, <i>Xenopus laevis</i>, 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 (<i>n</i> > 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.https://www.mdpi.com/1422-0067/22/24/13291<i>Xenopus laevis</i>metamorphosisneonicotinoidsliver enzymesgene expressionbiomarkers |
| spellingShingle | Jill A. Jenkins Katherine R. Hartop Ghadeer Bukhari Debra E. Howton Kelly L. Smalling Scott V. Mize Michelle L. Hladik Darren Johnson Rassa O. Draugelis-Dale Bonnie L. Brown Juvenile African Clawed Frogs (<i>Xenopus laevis</i>) Express Growth, Metamorphosis, Mortality, Gene Expression, and Metabolic Changes When Exposed to Thiamethoxam and Clothianidin International Journal of Molecular Sciences <i>Xenopus laevis</i> metamorphosis neonicotinoids liver enzymes gene expression biomarkers |
| title | Juvenile African Clawed Frogs (<i>Xenopus laevis</i>) Express Growth, Metamorphosis, Mortality, Gene Expression, and Metabolic Changes When Exposed to Thiamethoxam and Clothianidin |
| title_full | Juvenile African Clawed Frogs (<i>Xenopus laevis</i>) Express Growth, Metamorphosis, Mortality, Gene Expression, and Metabolic Changes When Exposed to Thiamethoxam and Clothianidin |
| title_fullStr | Juvenile African Clawed Frogs (<i>Xenopus laevis</i>) Express Growth, Metamorphosis, Mortality, Gene Expression, and Metabolic Changes When Exposed to Thiamethoxam and Clothianidin |
| title_full_unstemmed | Juvenile African Clawed Frogs (<i>Xenopus laevis</i>) Express Growth, Metamorphosis, Mortality, Gene Expression, and Metabolic Changes When Exposed to Thiamethoxam and Clothianidin |
| title_short | Juvenile African Clawed Frogs (<i>Xenopus laevis</i>) Express Growth, Metamorphosis, Mortality, Gene Expression, and Metabolic Changes When Exposed to Thiamethoxam and Clothianidin |
| title_sort | juvenile african clawed frogs i xenopus laevis i express growth metamorphosis mortality gene expression and metabolic changes when exposed to thiamethoxam and clothianidin |
| topic | <i>Xenopus laevis</i> metamorphosis neonicotinoids liver enzymes gene expression biomarkers |
| url | https://www.mdpi.com/1422-0067/22/24/13291 |
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