Help: Key Events

E Event Components and Biological Context

Cell Term/Organ Term

The location/biological environment in which the event takes place.

The biological context describes the location/biological environment in which the event takes place.  For molecular/cellular events this would include the cellular context (if known), organ context, and species/life stage/sex for which the event is relevant. For tissue/organ events cellular context is not applicable.  For individual/population events, the organ context is not applicable.  Further information on Event Components and Biological Context may be viewed on the attached pdf.

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Event Components

The KE, as defined by a set structured ontology terms consisting of a biological process, object, and action with each term originating from one of 14 biological ontologies (Ives, et al., 2017; Biological process describes dynamics of the underlying biological system (e.g., receptor signalling).

Biological process describes dynamics of the underlying biological system (e.g., receptor signaling).  The biological object is the subject of the perturbation (e.g., a specific biological receptor that is activated or inhibited). Action represents the direction of perturbation of this system (generally increased or decreased; e.g., ‘decreased’ in the case of a receptor that is inhibited to indicate a decrease in the signaling by that receptor).  

Note that when editing Event Components, clicking an existing Event Component from the Suggestions menu will autopopulate these fields, along with their source ID and description.  To clear any fields before submitting the event component, use the 'Clear process,' 'Clear object,' or 'Clear action' buttons.  If a desired term does not exist, a new term request may be made via Term Requests.  Event components may not be edited; to edit an event component, remove the existing event component and create a new one using the terms that you wish to add.  Further information on Event Components and Biological Context may be viewed on the attached pdf.

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L Other Information


List of the literature that was cited for this KE description.

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Comments and Discussion

See "Viewing and Commenting on AOPs" for instructions on how to comment or add to discussion on Key Events.

View History

See "View History" for details on how to view modifications to a KE page and revert to a previous version.

KE Watch list

The Watch List provides a list of individual AOP, KE, KER, or Prototypical Stressor that a user is currently watching, similar to Bookmarks on an internet browser.

A-C KE Identifier and Title


When a KE is created, an ID number is automatically assigned to it. This number is used for tracking the KE in the AOP-KB.

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A descriptive phrase which defines a discrete biological change that can be measured.

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Short name

The KE short name should be a reasonable abbreviation of the KE title and is used in labelling this object throughout the AOP-Wiki.

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F AOP Information

Other AOPs that use this KE

All of the AOPs that are linked to this KE will automatically be listed in this subsection. This table can be particularly useful for derivation of AOP networks including the KE.

Clicking on the name of the AOP will bring you to the individual page for that AOP.

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J MIE-Specific Content

Prototypical Stressors

A structured field used to identify specific agents (generally chemicals) that can trigger the KE.

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Evidence for Perturbation of this MIE by Prototypical Stressor

When a specific MIE can be defined (i.e., the molecular target and nature of interaction is known), in addition to describing the biological state associated with the MIE, how it can be measured, and its taxonomic, life stage, and sex applicability, it is useful to list prototypical stressors known to trigger the MIE and provide evidence supporting that initiation.

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D Level of Biological Organization

Level of Biological Organization

Structured terms, selected from a drop-down menu, are used to identify the level of biological organization for each KE.

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I Biological Domain of Applicability for KE


A description of the relevant biological domain(s) of applicability of the KE in terms of sex, life-stage, taxa, and other aspects of biological context.

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Taxonomic Applicability for KE

Latin or common names of a species or broader taxonomic grouping (e.g., class, order, family) that help to define the biological applicability domain of the KE.

In many cases, individual species identified in these structured fields will be those for which the strongest evidence used in constructing the AOP was available in relation to this KE.

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Life Stage Applicability for KE

An indication of the the relevant life stage(s) for this KE.

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Sex Applicability for KE

An indication of the the relevant sex for this KE.

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Evidence for Biological Domain of Applicability

A description of the scientific basis for the indicated domains of applicability and the WoE calls (if provided).

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G-H Describe the Key Event

Key Event Description

A description of the biological state being observed or measured, the biological compartment in which it is measured, and its general role in the biology should be provided.

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How it is Measured or Detected

A description of the type(s) of measurements that can be employed to evaluate the KE and the relative level of scientific confidence in those measurements.

These can range from citation of specific validated test guidelines, citation of specific methods published in the peer reviewed literature, or outlines of a general protocol or approach (e.g., a protein may be measured by ELISA). Do not provide detailed protocols.

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K AO-Specific Content

Regulatory Significance of the Adverse Outcome

An AO is a specialised KE that represents the end (an adverse outcome of regulatory significance) of an AOP.

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