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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:
22 April - 14 May 1988
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted in accordance with official test guidelines, and in compliance with GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report Date:
1998

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Unifoam AZ SO-L
- Substance type: yellow powder
- Physical state: solid
- Analytical purity: 100%
- Purity test date: none specified
- Storage condition of test material: stored at room temperature in the dark
- Particle suze: 6µm (average)

Method

Target gene:
Histidine operon (S. typhimurium)
Tryptophan operon (E. coli)
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 1538
Additional strain / cell type characteristics:
not applicable
Species / strain / cell type:
E. coli WP2 uvr A
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
S9 from liver of rats treated with i/p injection of Aroclor 1254 (diluted in Arachis oil to 200 mg/ml) at a dosage of 500 mg/kg.
Test concentrations with justification for top dose:
5000, 500, 50, and 5 µg/plate (range finding). 5000, 2500, 625, 312.5 µg/plate (mutation test).
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: dimethylsulphoxide
- Justification for choice of solvent/vehicle: solubility
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Wihtout S9: 2-aminoanthracene at 0.5 µg/plate (TA 1538, TA 98), at 1 µg/plate (TA 100), at 2 µg/plate (TA 1535, TA 1537), at 20 µg/plate (WP2 uvrA).
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Remarks:
Migrated to IUCLID6: With S9: at 3 µg/plate (TA 100), at 2 µg/plate (WP2 uvrA), at 5 µg/plate (TA 1535)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
Migrated to IUCLID6: With S9: at 80 µg/plate with TA 1537
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
Migrated to IUCLID6: With S9: at 1 µg/plate(TA 98), at 2 µg/plate (TA 1538)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation);

DURATION
- Preincubation period: None
- Exposure duration: 72 hours at 37°C

SELECTION AGENT (mutation assays): histidine or tryptophan

NUMBER OF REPLICATIONS: three at each dose level

NUMBER OF CELLS EVALUATED: 0.1 ml = 2x10^9 cells/ml

DETERMINATION OF CYTOTOXICITY
- Method: substantial reduction in revertant colony counts or by the absence of a complete background bacterial lawn
Evaluation criteria:
The mean number of revertant colonies for all treatment groups is compared with those obtained for negative and positive control groups. The effect of metabolic activation is assessed by comparing the results obtained both in the presence and absence of the liver microsomal fraction for each treatment group.
A compound is deemed to provide evidence of mutagenic potential if a statistically significant dose-related increase in the number of revertant colonies is obtained in two separate experiments.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium, other: TA100, TA1535
Metabolic activation:
with and without
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
not determined
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Species / strain:
S. typhimurium, other: TA1537, TA1538, TA98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not determined
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not determined
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
n both mutation tests, highly significant dose-related increases in revertant colony numbers were observed with tester strains TA 1535 and TA 100, particularly in the presence of metabolic activation, following treatment with Unifoam AZ SO-NL.
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):
positive

It is concluded that Unifoam AZ SO-NL shows clear evidence of mutagenic activity when tested in this bacterial system.
Executive summary:

A bacterial reverse mutation assay was performed to determine the potential of the test substance Unifoam AZ SO-NL to cause gene mutation (HLS 1988, OCI77/88757). The study was conducted in accordance with official test guidelines, and in compliance with GLP.

Five mutant strains of Salmonella Typhimurium (TA100, TA 1535, TA 98, TA 1537, and TA 1538) and one mutant strain of Escherichia coli (WP2 uvrA) were exposed to the test substance by plate incorporation. The test was performed both in the presence and in the absence of metabolic activation, and both negative (solvent) and relevant positive controls were used for each strain. A preliminary test was performed, and then a main mutation test was performed.

In both mutation tests, highly significant dose-related increases in revertant colony numbers were observed with tester strains TA 1535 and TA 100, particularly in the presence of metabolic activation, following treatment with Unifoam AZ SO-NL.

It is concluded that Unifoam AZ SO-NL shows clear evidence of mutagenic activity when tested in this bacterial system.