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Toxicological information

Genetic toxicity: in vitro

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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Principles of method if other than guideline:
- Factors modulating mutagenicity in microbial tests, Matsushima T, Sugimura T, Nagao M, Yahagi T, Shirai A, Sawamura M, in Short-term Test Systems for Detecting Carcinogens, Norpoth KH, Garner RC eds., Springer, Berlin-Heidelberg-New York (1980) pp.273-285
- Revised methods for the Salmonella mutagenicity test, Maron DM and Ames BN, Mutation Research 113: 173-215 (1983)
- Mutation testing using Trp reversion in Eschrichia coli, Green MHL, in Handbook of Mutagenicity Test Procedures, Kilbey BJ, Legator M, Nichols W, Ramel C eds., Elsevier, Amsterdam (1984) pp. 161-187
- Chemical Substance Research Section, Industrial Safety and Health Department, Labor Standards Bureau, Ministry of Labor Supervision: Mutagenicity study of existing chemical substances data collection based on Industrial Safety and Health Law Toxicity Investigation System, Japan Chemical Industry Ecology-Toxicology & Information Center, Tokyo, p.177 (1986)
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
S. typhimurium: histidin requirement
E. coli: tryptophan requirement
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Additional strain / cell type characteristics:
other: UV sensitivity, film mutation (rfa), ampicillin resistance factor pKM101 (plasmid)
Metabolic activation:
with and without
Metabolic activation system:
S9 mix (rat)
Test concentrations with justification for top dose:
313, 625, 1250, 2500 and 5000 µg/plate
Vehicle / solvent:
Vehicle/solvent used: DMSO
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: (5-nitro-2-furyl)acrylamide (AF-2), sodium azide (SA), 9-aminoacridine (9 AA), 2-aminoanthracene (2 AA)
Details on test system and experimental conditions:
METHOD OF APPLICATION: 1st and 2nd main experiment: pre-incubation method

DURATION
- Preincubation period: 20 minutes
- Exposure duration: 48 hours (37°C)

NUMBER OF REPLICATIONS: triplicates in two independent experiments

DETERMINATION OF CYTOTOXICITY: growth inhibition
Evaluation criteria:
When dosage dependence or repeatability in the absence and presence of S9 mix of more than 1 kind of assay bacteria, among the 5 kinds of assay bacteria used, was identified to be increasing, and the average value of the number of mutant colonies on the plate that includes the test material increased more than 2-fold of negative control value, it was determined (positive) as possessing gene mutagenesis in the study test system.
Statistics:
Statistic methodology was not used to determine the results.

Results and discussion

Test results
Key result
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
Increase of more than 2-fold of the negative control value was not identified in any of the assay bacteria used with and without S9 mix.
Deposits originated from the test material were not identified in any of the dosages used either in the absence or the presence of S9 mix.

Applicant's summary and conclusion

Conclusions:
Interpretation of results:
negative without metabolic activation
negative with metabolic activation

Under conditions tested, the test item did not induce gene mutations by base pair changes or frame-shifts in the genome of the tester strains used.
Thus, the test item is considered non-mutagenic in this bacterial reverse mutation assay.