Comparative toxicity assessment of glyphosate and two commercial formulations in the planarian Dugesia japonica
Introduction: Glyphosate is a widely used, non-selective herbicide. Glyphosate and glyphosate-based herbicides (GBHs) are considered safe for non-target organisms and environmentally benign at currently allowed environmental exposure levels. However, their increased use in recent years has triggered...
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Frontiers Media S.A.
2023-06-01
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| Series: | Frontiers in Toxicology |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/ftox.2023.1200881/full |
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| author | S. Grace Fuselier Danielle Ireland Nicholas Fu Christina Rabeler Eva-Maria S. Collins Eva-Maria S. Collins Eva-Maria S. Collins Eva-Maria S. Collins |
| author_facet | S. Grace Fuselier Danielle Ireland Nicholas Fu Christina Rabeler Eva-Maria S. Collins Eva-Maria S. Collins Eva-Maria S. Collins Eva-Maria S. Collins |
| author_sort | S. Grace Fuselier |
| collection | DOAJ |
| description | Introduction: Glyphosate is a widely used, non-selective herbicide. Glyphosate and glyphosate-based herbicides (GBHs) are considered safe for non-target organisms and environmentally benign at currently allowed environmental exposure levels. However, their increased use in recent years has triggered questions about possible adverse outcomes due to low dose chronic exposure in animals and humans. While the toxicity of GBHs has primarily been attributed to glyphosate, other largely unstudied components of GBHs may be inherently toxic or could act synergistically with glyphosate. Thus, comparative studies of glyphosate and GBHs are needed to parse out their respective toxicity.Methods: We performed such a comparative screen using pure glyphosate and two popular GBHs at the same glyphosate acid equivalent concentrations in the freshwater planarian Dugesia japonica. This planarian has been shown to be a useful model for both ecotoxicology and neurotoxicity/developmental neurotoxicity studies. Effects on morphology and various behavioral readouts were obtained using an automated screening platform, with assessments on day 7 and day 12 of exposure. Adult and regenerating planarians were screened to allow for detection of developmentally selective effects.Results: Both GBHs were more toxic than pure glyphosate. While pure glyphosate induced lethality at 1 mM and no other effects, both GBHs induced lethality at 316 μM and sublethal behavioral effects starting at 31.6 μM in adult planarians. These data suggest that glyphosate alone is not responsible for the observed toxicity of the GBHs. Because these two GBHs also include other active ingredients, namely diquat dibromide and pelargonic acid, respectively, we tested whether these compounds were responsible for the observed effects. Screening of the equivalent concentrations of pure diquat dibromide and pure pelargonic acid revealed that the toxicity of either GBH could not be explained by the active ingredients alone.Discussion: Because all compounds induced toxicity at concentrations above allowed exposure levels, our data indicates that glyphosate/GBH exposure is not an ecotoxicological concern for D. japonica planarians. Developmentally selective effects were not observed for all compounds. Together, these data demonstrate the usefulness of high throughput screening in D. japonica planarians for assessing various types of toxicity, especially for comparative studies of several chemicals across different developmental stages. |
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| format | Article |
| id | doaj.art-389ee529e0dc432e897a17650dd04f44 |
| institution | Directory Open Access Journal |
| issn | 2673-3080 |
| language | English |
| last_indexed | 2024-03-13T03:10:38Z |
| publishDate | 2023-06-01 |
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| spelling | doaj.art-389ee529e0dc432e897a17650dd04f442023-06-26T12:14:40ZengFrontiers Media S.A.Frontiers in Toxicology2673-30802023-06-01510.3389/ftox.2023.12008811200881Comparative toxicity assessment of glyphosate and two commercial formulations in the planarian Dugesia japonicaS. Grace Fuselier0Danielle Ireland1Nicholas Fu2Christina Rabeler3Eva-Maria S. Collins4Eva-Maria S. Collins5Eva-Maria S. Collins6Eva-Maria S. Collins7Department of Biology, Swarthmore College, Swarthmore, PA, United StatesDepartment of Biology, Swarthmore College, Swarthmore, PA, United StatesDepartment of Biology, Swarthmore College, Swarthmore, PA, United StatesDepartment of Biology, Swarthmore College, Swarthmore, PA, United StatesDepartment of Biology, Swarthmore College, Swarthmore, PA, United StatesDepartment of Physics and Astronomy, Swarthmore College, Swarthmore, PA, United StatesDepartment of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United StatesCenter of Excellence in Environmental Toxicology, University of Pennsylvania, Philadelphia, PA, United StatesIntroduction: Glyphosate is a widely used, non-selective herbicide. Glyphosate and glyphosate-based herbicides (GBHs) are considered safe for non-target organisms and environmentally benign at currently allowed environmental exposure levels. However, their increased use in recent years has triggered questions about possible adverse outcomes due to low dose chronic exposure in animals and humans. While the toxicity of GBHs has primarily been attributed to glyphosate, other largely unstudied components of GBHs may be inherently toxic or could act synergistically with glyphosate. Thus, comparative studies of glyphosate and GBHs are needed to parse out their respective toxicity.Methods: We performed such a comparative screen using pure glyphosate and two popular GBHs at the same glyphosate acid equivalent concentrations in the freshwater planarian Dugesia japonica. This planarian has been shown to be a useful model for both ecotoxicology and neurotoxicity/developmental neurotoxicity studies. Effects on morphology and various behavioral readouts were obtained using an automated screening platform, with assessments on day 7 and day 12 of exposure. Adult and regenerating planarians were screened to allow for detection of developmentally selective effects.Results: Both GBHs were more toxic than pure glyphosate. While pure glyphosate induced lethality at 1 mM and no other effects, both GBHs induced lethality at 316 μM and sublethal behavioral effects starting at 31.6 μM in adult planarians. These data suggest that glyphosate alone is not responsible for the observed toxicity of the GBHs. Because these two GBHs also include other active ingredients, namely diquat dibromide and pelargonic acid, respectively, we tested whether these compounds were responsible for the observed effects. Screening of the equivalent concentrations of pure diquat dibromide and pure pelargonic acid revealed that the toxicity of either GBH could not be explained by the active ingredients alone.Discussion: Because all compounds induced toxicity at concentrations above allowed exposure levels, our data indicates that glyphosate/GBH exposure is not an ecotoxicological concern for D. japonica planarians. Developmentally selective effects were not observed for all compounds. Together, these data demonstrate the usefulness of high throughput screening in D. japonica planarians for assessing various types of toxicity, especially for comparative studies of several chemicals across different developmental stages.https://www.frontiersin.org/articles/10.3389/ftox.2023.1200881/fullflatwormglyphosatenew approach methodbehavioral screeningneurotoxicityGBH |
| spellingShingle | S. Grace Fuselier Danielle Ireland Nicholas Fu Christina Rabeler Eva-Maria S. Collins Eva-Maria S. Collins Eva-Maria S. Collins Eva-Maria S. Collins Comparative toxicity assessment of glyphosate and two commercial formulations in the planarian Dugesia japonica Frontiers in Toxicology flatworm glyphosate new approach method behavioral screening neurotoxicity GBH |
| title | Comparative toxicity assessment of glyphosate and two commercial formulations in the planarian Dugesia japonica |
| title_full | Comparative toxicity assessment of glyphosate and two commercial formulations in the planarian Dugesia japonica |
| title_fullStr | Comparative toxicity assessment of glyphosate and two commercial formulations in the planarian Dugesia japonica |
| title_full_unstemmed | Comparative toxicity assessment of glyphosate and two commercial formulations in the planarian Dugesia japonica |
| title_short | Comparative toxicity assessment of glyphosate and two commercial formulations in the planarian Dugesia japonica |
| title_sort | comparative toxicity assessment of glyphosate and two commercial formulations in the planarian dugesia japonica |
| topic | flatworm glyphosate new approach method behavioral screening neurotoxicity GBH |
| url | https://www.frontiersin.org/articles/10.3389/ftox.2023.1200881/full |
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