Aop:4
Status
This is a legacy representation of this AOP. Please see the current version here:
AOP Title
Authors
You Song1 and Knut Erik Tollefsen1,2
1 Norwegian Institute for Water Research (NIVA), Section of Ecotoxicology and Risk Assessment, Gaustadalléen 21, N-0349 Oslo, Norway
2 Norwegian University of Life Sciences (NMBU), Faculty of Environmental Science and Technology, Department of Environmental Sciences (IMV). P.O. Box 5003, N-1432 Ås, Norway
Contact: knut.erik.tollefsen@niva.no
Status
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Under development: Do not distribute or cite.
This AOP was last modified on 12/5/2016.
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Abstract
Molting is a natural biological process in arthropods. During a molt cycle, the animals generate new exoskeletons by the epidermis and shed the old ones in order to grow. Successful molting is key to survival, development and reproduction. Over half a century research on arthropod endocrinology reveals that molting is precisely controlled by complex multi-hormone systems, with 20-hydroxyecdysone (20E) being the key effective hormone to mediate different biological processes that are necessary for molting. The hormonal actions of 20E are exerted through binding and modulation of the ecdysone receptors (EcR), which are nuclear transcriptional factors that regulate a wide range of physiological and behavioral changes. Based on this knowledge, endocrine disrupting chemicals (EDCs) targeting at the EcRs are developed as pesticides and anti-parasite pharmaceuticals in order to disrupt the molting cycles of “harmful” arthropods and protect the agriculture and aquaculture. However, environmental residues of these EDCs may also affect non-target species, such as a number of crustaceans (e.g. crabs and lobsters) with great ecological and economical values, due to highly conserved endocrine systems in arthropods. Substantial efforts are therefore needed to assess the environmental hazards and risks of EDCs on non-target species. Due to the high number (over a million described) of species in the phylum of Arthopoda, it is not feasible to perform toxicity testing for each species as well as EDC. Construction of universal models on basis of systems (eco)toxicology and phylogenetic similarities for understanding the environmental endocrine disruption (ED) effects may serve as a potential solution. The current AOP is therefore developed based on available information in the databases to identify knowledge gaps in this research field. The conceptual AOP will be further expanded using a combination of laboratory studies and advance in sillico predictions of potential EcR ligands and taxonomic appllicablity to inform environmental risk assessment as an ultimate goal.
Summary of the AOP
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Molecular Initiating Event
Molecular Initiating Event | Support for Essentiality |
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Ecdysone receptor, Activation | Strong |
Key Events
Adverse Outcome
Adverse Outcome |
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Food-web structures, Alterations |
Mortality, Increased |
Population size, Decreased |
Relationships Among Key Events and the Adverse Outcome
Network View
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Life Stage Applicability
Life Stage | Evidence | Links |
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Juvenile | Strong | |
Adult | Moderate |
Taxonomic Applicability
Name | Scientific Name | Evidence | Links |
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insects | Strong | ||
crustaceans | Moderate |
Sex Applicability
Sex | Evidence | Links |
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Unspecific | Moderate |
Graphical Representation
Overall Assessment of the AOP
Weight of Evidence Summary
Summary Table
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Essentiality of the Key Events
Molecular Initiating Event Summary,
Key Event Summary
Provide an overall assessment of the essentiality for the key events in the AOP. Support calls for individual key events can be included in the molecular initiating event, key event, and adverse outcome tables above.
Quantitative Considerations
Summary Table
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Applicability of the AOP
Life Stage Applicability,
Taxonomic Applicability,
Sex Applicability
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