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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:
Apr 22 - Nov 04, 1992
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
Principles of method if other than guideline:
none
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
solid: crystalline
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Lot No. E631441
- Expiration date of the lot/batch: 1992-12-20

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: stable
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: soluble in acetone
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: no reactivity

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: no
- Preliminary purification step (if any): no
- Final dilution of a dissolved solid, stock liquid or gel: solution
- Final preparation of a solid: dissolved in acetone

Method

Target gene:
HIS operon (S. thyphimurium)
TRY operon (E. coli)
Species / strainopen allclose all
Species / strain:
S. typhimurium TA 1535
Details on mammalian cell lines (if applicable):
his G 46, uvrB, rfa
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
rat liver homogenate (S9 mix) with standard co-factors with metabolic activation (Aroclor)
Species / strain:
S. typhimurium TA 1537
Details on mammalian cell lines (if applicable):
his C 3076, uvrB, rfa
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
S. typhimurium TA 98
Details on mammalian cell lines (if applicable):
his D 3052, uvrB, rfa + R-factor
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
S. typhimurium TA 100
Details on mammalian cell lines (if applicable):
his G 46, uvrB, rfa + R-factor
Additional strain characteristics:
other: mutations in the histidine operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
E. coli WP2
Details on mammalian cell lines (if applicable):
trp C 3076, uvrB, rfa
Additional strain characteristics:
other: mutations in the tryptophan operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
E. coli WP2 uvr A
Details on mammalian cell lines (if applicable):
The WP2 uvrA-strain not only possesses the tryptophan mutation, but also lacks excision repair (uvrA), so that it is more readily mutated by agents such as UV.
Additional strain characteristics:
other: mutations in the tryptophan operon
Metabolic activation:
with and without
Metabolic activation system:
liver S9 mix from Aroclor 1254-pretreated rats with standard co-factors
Species / strain:
S. typhimurium TA 1538
Details on mammalian cell lines (if applicable):
his D 3052 mutation
Metabolic activation:
with and without
Metabolic activation system:
rat liver homogenate (S9 mix) with standard co-factors with metabolic activation (Aroclor)
Test concentrations with justification for top dose:
The test material concentrations were used selected according to the EC and OECD guidelines for this test system and the requirements of the Labor Ministry of Japan: 50-1000 µg/plate have been used in the 1st and 2nd series respectively. Precipitation of the test material accured at concentrations larger or equal to 1000 µg/plate.

Vehicle:
Acetone
Controlsopen allclose all
Positive controls:
yes
Positive control substance:
cumene hydroperoxide
Negative controls:
yes
Solvent controls:
yes
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Positive controls:
yes
Positive control substance:
9-aminoacridine
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
with S9
Positive controls:
yes
Positive control substance:
other: daunomycine
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
with S9
Details on test system and conditions:
The assessment of test material-induced effects is dependent on the number of spontaneous revertants of each bacterial strain (solvent controls) and the increase in the number of revertants at the test material concentration which shows the highest number of colonies.
The following criteria, based upon the historical controls of the laboratory and statistical considerations, are established:

-----------------------------------------------------------------------------------------
Mean Number of Colonies Maximal Mean Number of Colonies over the Actual
(Solvent Control) Solvent Control
(Test Material)
-----------------------------------------------------------------------------------------

<=10 <=9 >=30
<=30 <=19 >=40
<=80 <=29 >=80
<=200 <=49 >=120
<=500 <=79 >=200
Assessment No increase Clear increase

-----------------------------------------------------------------------------------------

All further results, ranging between "no" and "clear", are assessed as "weak in-creases".
Interpretations:
A test material is defined as non-mutagenic in this assay if "no" or "weak increases" occur in the first and second series of the main experiment.
("Weak increases" randomly occur due to experimental variation.)

A test material is defined as mutagenic in this assay if:

- a dose-related (over at least two test material concentrations) increase in the number of revertants is induced, the maximal effect is a "clear increase", and the effects are reproduced at similar concentration levels in the same test system;

- "clear increases" occur at least at one test material concentration, higher concentrations show strong precipitation or cytotoxicity, and the effects are reproduced at the same concentration level in the same test system.

In all further cases, a third test series with the bacterial strain in question should be performed.
If the criteria for a positive test result are not fulfilled in at least two out of the three series, the test material is defined as being non-mutagenic in this test system.

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Key result
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Key result
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Additional information on results:
Precipitation occured at concentrations higher or equal to 1000 µg/plate. Toxicity to bacteria was not observed.

Applicant's summary and conclusion

Conclusions:
With and without addition of S9 mix as the external metabolizing system, the test item was not mutagenic under the experimental conditions described.
Executive summary:

This study was performed according to GLP and the methods applied are fully compliant with OECD TG 471.

With and without addition of S9 mix as the external metabolizing system, the test material was not mutagenic under the experimental conditions described.