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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
Study period:
1990-04-25 to 1990-06-22
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline-conform study under GLP without deviations.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1990
Report Date:
1990

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
adopted May 26, 1983
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.5265 (The Salmonella typhimurium Bacterial Reverse Mutation Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
The strains are derived from S. typhimurium strain LT2 and due to a mutation in the histidine locus are histidine dependent.
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
other: Due to the "deep rough" (rfa -) mutation the bacteria possess a faulty lipopolysaccharide envelope which enables substances to penetrate the cell wall more easily. A further mutation causes a reduction in the activity of an excision repair system (uvrB -)
Metabolic activation:
with and without
Metabolic activation system:
Mammalian microsomal fraction S9 mix
Test concentrations with justification for top dose:
Concentration range in the main test (with metabolic activation): 10 ... 5000 µg/plate
Concentration range in the main test (without metabolic activation): 10 ... 5000 µg/plate
Vehicle / solvent:
Solvent: Distilled water
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: Without metabolic activation: sodium azide (TA 1535, TA 100), 4-nitro-o-phenylene-diamine 4-NOPD (TA 1537, TA 98). With metabolic activcation: 2-aminoanthracene 2-AA (all strains)
Details on test system and experimental conditions:
METHOD OF APPLICATION:
This study was performed according to the plate incorporation test using the Salmonella typhimurium strains TA 1535, TA 1537, TA 98 and TA 100. The assay was performed in two independent experiments, using identical procedures, both with and without liver microsomal activation. After solidification the plates were incubated for 72 hours at 37° C in the dark.

DURATION
- Preincubation: not applicable
- Exposure duration: 72 h
- Expression time: 72 h

NUMBER OF REPLICATIONS: 3 plates per concentration / control

DETERMINATION OF CYTOTOXICITY
- Method: Toxicity of the test article may be evidenced by a reduction in the number of spontaneous revertants, a clearing of the bacterial background lawn, or by degree of survival of treated cultures.
Evaluation criteria:
A test article is considered as positive if either a significant dose-related increase in the number of revertants or a significant and reproducible increase for at least one test concentration is induced.

A test article producing neither a significant dose-related increase in the number of revertants nor a significant and reproducible positive response at any one of the test points is considered non-mutagenic in this system.

A significant response is described as follows:
A test article is considered as mutagen if in strain TA 100 the number of reversions is at least twice as high and in strains TA 1535, TA 1537 and TA 98 it is at least three times higher as compared to the spontaneous reversion rate (defined in the original study report).
Also, a dose-dependent increase in the number of revertants is regarded as an indication of possibly existing mutagenic potential of the test article regardless whether the highest dose induced the above described enhancement factors or not.
Statistics:
No appropriate statistical method is available

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
5000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
1000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
5000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
>= 1000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'. Remarks: experiment I and II

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The substance is considered to be non mutagenic in this Salmonella typhimurium reverse mutation assay.