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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:
21.04.1998-26.05.1998
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and guideline study

Data source

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

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
GLP compliance:
yes (incl. certificate)
Remarks:
testing lab.
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
S. typhimurium and E. coli
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
microsomal enzyme system (S-9 mix) from Aroclor 1254 induced Sprague Dawley rat liver
Test concentrations with justification for top dose:
20 µg - 5000 µg/plate (standard plate test and preincubation test)
Vehicle / solvent:
DMSO
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Positive control substance:
other: 2-amninoanthracene
Remarks:
with S-9 mix, in TA 1535, TA 100, TA 1537, TA 98, Escherichia coli WP2 uvrA
Positive controls:
yes
Positive control substance:
other: aniline and o-toluidine
Remarks:
with S-9 mix and norharman, in TA 98
Positive controls:
yes
Positive control substance:
other: N-methyl-N'-nitro-N-nitrosoguanidine
Remarks:
without S-9 mix, in TA 1535, TA 100
Positive controls:
yes
Positive control substance:
other: 4-nitro-o-phenylendiamine
Remarks:
without S-9 mix, TA 98
Positive controls:
yes
Positive control substance:
other: 9-amninoacridine
Remarks:
without S-9 mix, TA 1537
Positive controls:
yes
Positive control substance:
other: 4-Nitroquinoline-N-Oxide
Remarks:
without S-9 mix, E. coli WP uvrA
Details on test system and experimental conditions:
METHOD OF APPLICATION: standard plate and preincubation method

DURATION
- Preincubation period: 20 minutes
- Expression time (cells in growth medium): 48-72 h

NUMBER OF PLATES: 3 per dose or control

DETERMINATION OF CYTOTOXICITY
- Method:
Examination of background lawn and comperison of spontaneous revertants with control
The titer of viable bacteria was >= 10E9/mL


Evaluation criteria:
The test chemical is considered positive in this assay if the following criteria are met:
- A dose-related and reproducible increase in the number of revertant colonies, i.e. about doubling of the spontaneous mutation rate in at least one tester strain either without S-9 mix or after adding a metabolizing system.
A test substance is generally considered nonmutagenic in this test if:
- The number of revertants for all tester strains were within the historical negative control range under all experimental conditions in two experiments carried out independently of each other.

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:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not valid
Positive controls validity:
valid
Additional information on results:
An increase in the number of his+ or trp+ revertants was not observed in the standard plate test or in the preincubation test either without S-9 mix or after the addition of a metabolizing system.
The number of revertant colonies in the negative controls was within the normal range of the historical control data for each tester strain
The sterility controls revealed no indication of bacterial contamination
The positive control articles both with and without S-9 mix induced a significant increase in the number of revertant colonies within the range of the historical control data.
Cytotoxicity:
S.thyphimurium TA 1535, TA 1537, TA 98 and TA 100
standard plate test: slight decrease his+ revertants in the about 5000 µg/plate (TA 1535, TA 100, TA 1537) and 2500 µg/plate onward (TA 98). The preincubation assay: bacteriotoxicity from about 2500 µg/plate (Salmonella strains).
E.coli and WP2 uvr A
Preincubaton assay: bacteriotoxicity at 5000 µg/plate
Precipitation: was not found
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion