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:
9 July - 17 November, 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
In the second test, no concentration was tested at with precipitation was observed.
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent

Method

Target gene:
Histidine gene in S. typhimurium
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 102
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced rat liver post-mitochondrial fraction (S9)
Test concentrations with justification for top dose:
First test: 313 - 625 - 1250 - 2500 - 5000 µg/plate
Second test: 125 - 250 - 500 - 750 - 1000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: not indicated
Controlsopen allclose all
Positive controls:
yes
Remarks:
without S9
Positive control substance:
sodium azide
Remarks:
For strains TA 100 and TA 1535

Migrated to IUCLID6: 2 µg/plate (both strains)
Positive controls:
yes
Remarks:
without S9
Positive control substance:
9-aminoacridine
Remarks:
For strain TA 1537

Migrated to IUCLID6: 35 µg/plate
Positive controls:
yes
Remarks:
without S9
Positive control substance:
2-nitrofluorene
Remarks:
For strain TA 98

Migrated to IUCLID6: 4 µg/plate
Positive controls:
yes
Remarks:
with S9
Positive control substance:
other: 2-aminoanthracene at 2, 2, 7 and 10 µg/plate
Remarks:
For strain TA 1535, TA 100, TA 1537 and TA 102, respectively
Positive controls:
yes
Remarks:
with S9
Positive control substance:
benzo(a)pyrene
Remarks:
For strain TA 98

Migrated to IUCLID6: 30 µg/plate
Positive controls:
yes
Remarks:
without S9
Positive control substance:
mitomycin C
Remarks:
For strain TA 102

Migrated to IUCLID6: 0.5 µg/plate
Untreated negative controls:
yes
Remarks:
DMSO, with and without S9
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: at least 48 h

NUMBER OF REPLICATIONS: doses of the test substance were tested in triplicate in each strain. Negative control was tested six fold. Two independent experiments were conducted.

DETERMINATION OF CYTOTOXICITY
- Method: toxicity to the background lawn and colonies of his+ revertants

Evaluation criteria:
If the number of revertants is at least twice the spontaneous reversion rate in one of the strains and if there is a concentration related increasing number of revertants over the range tested then a biological relevant response is observed and the test substance is considered mutagenic.

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, but tested up to precipitating concentrations
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity, but tested up to precipitating concentrations
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: observed at concentrations of 1250 µg/plate and higher in the first test. No precipitation was observed in the second test up to concentrations of 1000 µg/plate.

COMPARISON WITH HISTORICAL CONTROL DATA: negative controls were in the historical ranges

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The negative controls were within the historical ranges and the positive controls all induced large increases in the revertant numbers. The strain characteristics of the bacteria have been confirmed. The study was therefore accepted as valid.
Compared to the negative control group the test substance does not indicate an elevation of the revertant colonies neither in the absence nor in the presence of S9-mix. It was concluded that the test substance did not induce mutation in five strains of Salmonella typhimurium and is not toxic when tested under the conditions employed for this study.
Executive summary:

The potential of the substance to induce mutations was assessed in a bacterial reverse mutation assay. The study was conducted in accordance with OECD Guideline 471. The assay was performed in two independent experiments. Both took place as a plate incorporation test using the Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102. All experiments were in the absence and in the presence of a metabolic activation by an Aroclor 1254 induced rat liover post mitochondrial fraction (S9). Five concentrations were tested in each experiment using 0.1 ml for each plate. No mutagenic effects occurred with or without metabolic activation in experiment 1 (313, 625, 1250, 2500 and 5000 µg/plate). Precipitation was observed at a concentration >= 1250 µg/plate at all tester strains. In experiment 2 (125, 250, 500, 750, 1000 µg/plate) no mutagenic or toxic effects occurred. Precipitation was not observed at any concentration.

It can be concluded that the test substance did not induce gene mutations by base pair substitution or frame shifts in the genom of the used strains. Therefore the test substance is considered to be non mutagenic in the bacterial reverse mutation assay.