Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
11 May 2015 to 08 June 2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Compliance with GLP and testing guidelines; coherence among data, results and conclusions.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial gene mutation assay

Test material

Constituent 1
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
Test item: Disperse Red DYGJ 0702


Method

Target gene:
The test item Disperse Red DYGJ 0702 was examined for the ability to induce gene mutations in tester strains of Salmonella typhimurium and Escherichia coli, as measured by reversion of auxotrophic strains to prototrophy.
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Metabolic activation:
with and without
Metabolic activation system:
S9 liver homogenate from induced rat (rat mixed induction)
Test concentrations with justification for top dose:
In Main Assay the following concentrations were tested:
TA1535 ( ± S9) : 2500, 1250, 625, 313 and 156
TA1537 ( ± S9): 1250, 625, 313, 156, 78.1 and 39.1
WP2 uvrA (-S9): 5000, 2500, 1250, 625 and 313
(+S9): 2500, 1250, 625, 313 and 156
TA98 ( ± S9): 2500, 1250, 625, 313 and 156
TA100 ( ± S9): 1250, 625, 313, 156 and 78.1
Vehicle / solvent:
DMSO
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Positive control substance:
9-aminoacridine
2-nitrofluorene
sodium azide
methylmethanesulfonate
other: 2-aminoanthracene
Details on test system and experimental conditions:
Toxicity and Main Assay were performed using the plate incorporation method.
Evaluation criteria:
For the test item to be considered mutagenic, two-fold (or more) increases in mean revertant numbers must be observed at two consecutive dose levels or at the highest practicable dose level only. In addition, there must be evidence of a dose-response relationship showing increasing numbers of mutant colonies with increasing dose levels.
Statistics:
Doubling rate (Chu et al. 1981)
Regression line

Results and discussion

Test results
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Metabolic activation:
with and without
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
The test item induced large increases in the number of revertant colonies in all tester strains in the absence and presence of S9 metabolism. Since a clear positive response was observed, no further experiment was undertaken.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
It is concluded that the test item Disperse Red DYGJ 0702 induces reverse mutation by base substitutions or frameshifts in Salmonella typhimurium and Escherichia coli in the absence and presence of S9 metabolism, under the reported experimental conditions.
Executive summary:

The test item Disperse Red DYGJ 0702 was examined for the ability to induce gene mutations in tester strains of Salmonella typhimurium and Escherichia coli, as measured by reversion of auxotrophic strains to prototrophy. The five tester strains TA1535, TA1537, TA98, TA100 and WP2 uvrA were used. Experiments were performed both in the absence and presence of metabolic activation, using liver S9 fraction from rats pre-treated with phenobarbitone and betanaphthoflavone. The test item was used as a solution in dimethylsulfoxide (DMSO).

Toxicity test: The test item Disperse Red DYGJ 0702 was assayed in the toxicity test at a maximum concentration of 5000 µg/plate and at four lower concentrations spaced at approximately half-log intervals: 1580, 500, 158 and 50.0 µg/plate. Heavy precipitation of the test item was observed at the end of the incubation period at the highest concentration tested which iterfered the evaluation of background lawn and in some cases also with the colony counting. Toxicity, as indicated by thinning of background lawn, reduction in revertant numbers or microcolony formation was observed with all tester strains at the two higher dose levels, in the absence and presence of S9 metabolism. Toxicity was more pronounced with TA100 tester strain in the absence of S9, where thinning of background lawn was observed over the whole dose range tested.

Main Assay I: On the basis of toxicity test results, in Main Assay I, using the plate incorporation method, the test item was assayed at the following dose levels:

TA1535 ( ± S9) : 2500, 1250, 625, 313 and 156

TA1537 ( ± S9): 1250, 625, 313, 156, 78.1 and 39.1

WP2 uvrA (-S9): 5000, 2500, 1250, 625 and 313

(+S9): 2500, 1250, 625, 313 and 156

TA98 ( ± S9): 2500, 1250, 625, 313 and 156

TA100 ( ± S9): 1250, 625, 313, 156 and 78.1

Toxicity as indicated by thinning of background lawn was observed with all tester strains at the highest or two highest dose levels in the absence and presence of S9 metabolism. Toxicity was more pronounced with TA1537 and TA100 in the absence of S9 metabolism where thinning of background lawn was also present at lower dose levels. Precipitation of the test item which did not interfere with scoring was observed at the end of the incubation period at the highest concentration tested in the absence of S9 metabolism for all tester strains and at one or two next lower dose levels for TA1535 and WP2 uvrA respectively. In the presence of S9 metabolism, precipitation of the test item which did not interfere with scoring was observed at the highest concentration tested for the tester strain TA1535 and at the two highest concentrations tested for WP2 uvrA. The test item induced large increases in the number of revertant colonies in all tester strains in the absence and presence of S9 metabolism. Since a clear positive response was observed, no further experiment was undertaken

Conclusion: It is concluded that the test item Disperse Red DYGJ 0702 induces reverse mutation by base substitutions or frameshifts in Salmonella typhimurium and Escherichia coli in the absence and presence of S9 metabolism, under the reported experimental conditions.