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Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

- Ames Test on S. typhimurium TA98, TA100, TA1535, TA1537, TA1538 (Sivak, 1983): inconclusive due to severe toxic effects

- QSAR prediction (DEREK, 2017): No structural alerts for mutagenicity

Link to relevant study records

Referenceopen allclose all

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
15 Jul 1982 - 15 Dec 1982
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
E. coli not tested
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay
Specific details on test material used for the study:
- Name of test material as cited in the report : exo-tetrahydrodi(cyclopentadiene); JP-10
- Storage conditions: stored at room temperature in a safety cabinet.
Target gene:
Histidine
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Details on mammalian cell type (if applicable):
Not applicable
Species / strain / cell type:
S. typhimurium TA 1538
Details on mammalian cell type (if applicable):
Not applicable
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced rat liver microsomal fraction, S9
Test concentrations with justification for top dose:
1, 5, 10, 20 and 50 µl/plate
Vehicle / solvent:
DMSO
Negative solvent / vehicle controls:
yes
Remarks:
the highest volume of DMSO used
Positive controls:
yes
Positive control substance:
9-aminoacridine
2-nitrofluorene
sodium azide
other: 2-aminoanthracene
Details on test system and experimental conditions:
METHOD OF APPLICATION: preincubation

JP-10 which was immiscible with the top agar overlay was assayed using a preincubation modification of the Ames assay which alters the conditions of exposure of tester strains to test chemicals to enhance exposure. As for the standard assay, bacteria (0.05 ml), the metabolic activation mixture (0.5 ml) or saline (for assays in the absence of S9) and the test substance (0.05 ml or less) were combined in a test tube. Before the addition of 2.0 ml of top agar, however, the tubes containing bacteria, enzymes and test material were incubated at 37°C for 30 minutes with end-over-end rotation. At that time, the 2.0 ml of top agar was added and the top agar layer was plated in the usual way. The doses of positive control chemicals per plate were as follows: 2-aminoanthracene, 25 µg; 2-nitrofluorene, 5 µg; sodium azide, 1 µg; and 9-aminoacridine, 50 µg.
Rationale for test conditions:
A liquid pre-incubation modification (standard operating procedure #CB/M-818) was used to test JP-10 which was not compatible with the standard plate-incorporation assay since it formed oil-like droplets on the surface of the top agar layer.
Key result
Species / strain:
S. typhimurium, other: TA98, TA100, TA1535, TA1537, TA1538
Metabolic activation:
with and without
Genotoxicity:
not determined
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
even at the lowest dose tested (1µl/plate)
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Even at the lowest dose tested (1 µl/plate) toxicity was severe enough to result in sparse background lawns. Many plates had no revertants rather than the number normally obtained as a result of spontaneous reversion.

Table of results: see attached document

Conclusions:
Under the test conditions, the test material is too cytotoxic to determine its mutagenic potential.
Executive summary:

JP-10 was assayed by a preincubation modification of the Ames assay because it was immiscible with the agar medium used in this assay. Varying volumes of the undiluted test material were added directly to the bacteria and S9 (or saline) mixes for preincubation because JP-10 was not sufficiently soluble in DMSO to obtain the necessary concentrates for the desired doses. Even at the lowest dose tested (1 µl/plate) toxicity was severe enough to result in sparse background lawns. Many plates had no revertants rather than the number normally obtained as a result of spontaneous reversion.

The results of this assay are inconclusive due to severe toxicity of JP-10 on the tester strains. Although a repeat assay with shorter exposure times is recommended, we consider that further modifications of the standard protocol for this particularly toxic test substance are outside the scope of this present work assignment.

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Study period:
20 November 2017
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Remarks:
DEREK is a validated (Q)SAR software, widely used to predict genotoxicity properties
Justification for type of information:
1. SOFTWARE
Derek Nexus: 5.0.2, Nexus: 2.1.1, Lhasa Ltd.

2. MODEL (incl. version number)
Derek KB 2015 v2.0

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
C3CC2C1CCC(C1)C2C3

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF

5. APPLICABILITY DOMAIN
See attached report

6. ADEQUACY OF THE RESULT
See attached report
Qualifier:
no guideline followed
Principles of method if other than guideline:
Software used: Derek Nexus: 5.0.2, Nexus: 2.1.1, Lhasa Ltd.
GLP compliance:
no
Type of assay:
other: Derek Nexus evaluation for mutagenicity
Target gene:
Not applicable
Species / strain / cell type:
bacteria, other: Salmonella typhimurium and Escherichia coli
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
not applicable
Test concentrations with justification for top dose:
Not applicable
Vehicle / solvent:
Not applicable
Details on test system and experimental conditions:
Not applicable
Rationale for test conditions:
Not applicable
Evaluation criteria:
Not applicable
Statistics:
Not applicable
Key result
Species / strain:
bacteria, other: Salmonella typhimurium and Escherichia coli
Metabolic activation:
not applicable
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: not applicable
Vehicle controls validity:
not applicable
Untreated negative controls validity:
not applicable
Positive controls validity:
not applicable
Additional information on results:
Mutagenicity in vitro in bacterium is INACTIVE: No misclassified or unclassified features
Mutagenicity in vitro in Escherichia coli is INACTIVE: No misclassified or unclassified features
Mutagenicity in vitro in Salmonella typhimurium is INACTIVE: No misclassified or unclassified features

Details
The query structure does not match any structural alerts or examples for (bacterial in vitro) mutagenicity in Derek. Additionally, the query structure does not contain any unclassified or misclassified features and is consequently predicted to be inactive in the bacterial in vitro (Ames) mutagenicity test.

None

Conclusions:
DEREK Nexus evaluation showed no alerts for mutagenicity.
Executive summary:

DEREK software (Derek Nexus: 5.0.2, Nexus: 2.1.1, Lhasa Ltd.) was used to predict the mutagenicity of tetrahydrodicyclopentadiene.

The query structure does not match any structural alerts or examples for (bacterial in vitro) mutagenicity in Derek. Additionally, the query structure does not contain any unclassified or misclassified features and is consequently predicted to be inactive in the bacterial in vitro (Ames) mutagenicity test.

DEREK Nexus evaluation showed no alerts for mutagenicity.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

In an old study performed in 1983, tetrahydrodicyclopetadiene, designed as "JP-10", was assayed by a preincubation modification of the Ames assay because it was immiscible with the agar medium used in this assay. Varying volumes of the undiluted test material were added directly to the bacteria and S9 (or saline) mixes for preincubation because JP-10 was not sufficiently soluble in DMSO to obtain the necessary concentrates for the desired doses (from 1 to 50 µl/plate).

Even at the lowest dose tested (1 µl/plate) toxicity was severe enough to result in sparse background lawns. Many plates had no revertants rather than the number normally obtained as a result of spontaneous reversion.

The results of this assay are then inconclusive due to severe toxicity of JP-10 on the tester strains.

However, the mutagenic potential of tetrahydrodicyclopentadiene was evaluated with Derek software.

The query structure does not match any structural alerts or examples for (bacterial in vitro) mutagenicity in Derek. Additionally, the query structure does not contain any unclassified or misclassified features and is consequently predicted to be inactive in the bacterial in vitro (Ames) mutagenicity test.

Justification for classification or non-classification

Harmonised classification

The test material has no harmonised classification for human health according to the Regulation (EC) No. 1272/2008 (CLP).

Self classification

No additional classification is proposed regarding in vitro genetic toxicity according to the criteria of Annex I to the Regulation (EC) No. 1272/2008 (CLP) and to the GHS.