Registration Dossier

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:
From Feb. 2, 1988 to Aug. 5, 1988
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented, according to accepted guideline, with GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report Date:
1988

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 1538
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 - induced rat liver S9 mix
Test concentrations with justification for top dose:
Concentration range in the main tests (with metabolic activation): 5, 10, 50, 100, 500, 1000 and 5000 μg/0.1 ml
Concentration range in the main tests (without metabolic activation): 5, 10, 50, 100, 500, 1000 and 5000 μg/0.1 ml
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Dimethylsulfoxide
Controlsopen allclose all
True negative controls:
yes
Remarks:
Dimethylsulfoxide
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
without metabolic activation for strains TA98 and TA 1538
True negative controls:
yes
Remarks:
Dimethylsulfoxide
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Remarks:
without metabolic activation for strains TA 100 and WP2 uvrA
True negative controls:
yes
Remarks:
Dimethylsulfoxide
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
without metabolic activation for strain TA 1535
True negative controls:
yes
Remarks:
Dimethylsulfoxide
Positive controls:
yes
Positive control substance:
other: 9(5)aminoacridine hydrochloride monohydrate
Remarks:
without metabolic activation for strain TA 1537
True negative controls:
yes
Remarks:
Dimethylsulfoxide
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
with metabolic activation for strains TA 98, TA 100, TA 1537 and TA 1538
True negative controls:
yes
Remarks:
Dimethylsulfoxide
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
with metabolic activation for strains TA 1535 and WP2 uvrA
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hours at 37°C

NUMBER OF REPLICATIONS: 3 plates per test
Evaluation criteria:
The test substance is considered to be positive in this test system if one or both of the following conditions are met:
- at least a reproducible doubling of the mean number of revertants per plate above that of the negative control at any concentration level for one or more of the following strains: TA 98, TA 1535, TA 1537, TA 1538 and E. coli WP2uvrA,
- a reproducible increase of the mean number of revertants per plate for any concentration above that of the negative control by at least a factor of 1.5 for strain TA 100.
Generally a concentration-related effect should be demonstrable.
Statistics:
No statistical analysis was performed.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
In the experiments performed without and with microsomal activation, comparison of the number of both histidine- or tryptophanprototrophic mutants in the controls and after treatment with TK 13010/ZP revealed no marked differences.

Owing to a growth-inhibiting effect of the test substance in the experiments without and with microsomal activation a reduction on the colony count occasionally occurred on strains TA 1535, TA 1537 and TA 1538 at the highest concentration.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative with and without metabolic activation

No evidence of the induction of point mutations by the test article or by the metabolites of the substance formed as a result of microsomal activation was detectable in the strains of S. typhimurium and Escherichia coli used in these experiments.
Executive summary:

The test item was analysed for mutagenic effects on histidine-auxotrophic mutants of Salmonella typhimurium and on a tryptophan-auxotrophic strain of E. coli. The investigations were performed with the following concentrations of the trial substance without and with microsomal activation: 5, 10, 50, 100, 500, 1000 and 5000 ug/0.1 ml. In order to confirm the results, the experiments were repeated. These tests permit the detection of point mutations in bacteria induced by chemical substances. Any mutagenic effects of the substances are demonstrable on comparison of the number of bacteria in the treated and control cultures that have undergone back-mutation to histidine-prototrophism. To ensure that mutagenic effects of metabolites of the test substances formed in mammals would also be detected, experiments were performed in which the cultures were additionally treated with an activation mixture (rat liver microsomes and co-factors). In the experiments performed without and with microsomal activation, comparison of the number of back-mutant colonies in the controls and the cultures treated with the various concentrations of the test substance revealed no marked deviations. Owing to a growth-inhibiting effect of the test substance in the experiments without and with microsomal activation a reduction on the colony count was occasionally observed with strains TA 1535, TA 1537 and TA 1538 at the highest concentration. No evidence of the induction of point mutations by the test article or by the metabolites of the substance formed as a result of microsomal activation was detectable in the strains of S. typhimurium and Escherichia coli used in these experiments.