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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD Guideline Study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1993
Report Date:
1993

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes
Remarks:
Centre International de Toxicologie, Evreux, France
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): 2,6-DCPTFMA
- Analytical purity: 89.7%
- Lot/batch No.: 51ADM92
- Storage condition of test material: room temperature

Method

Target gene:
his
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 induced rat liver S9-mix
Test concentrations with justification for top dose:
without S9-mix:
1st test: 6.25, 12.5, 25, 50 and 100 µg/plate
2nd test: 3.175, 6.25, 12.5, 25 and 50µg/plate,
with S9 mix:
1st test: 31.25, 62.5, 125, 250 and 500 µg/plate
2nd test: 12.5, 25, 50, 100 and 200 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
without S9-mix for TA1535 and TA100
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
without S9-mix for TA1537
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
without S9-mix for TA98
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
mitomycin C
Remarks:
without S9-mix for TA102
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Anthramine
Remarks:
with S9-mix for TA1535, TA100, TA98, TA1537
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Danthron
Remarks:
with S9-mix for TA102
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION
- Preincubation period: 60 minutes
- Exposure duration: 48 - 72h

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth
Evaluation criteria:
The following criteria were used as an aid for determining a positive response:
- a reproducible and significant dose relationship using a linear regression analysis, considered as significant if p ≤ 0.05 (for n = 18 values, the correlation coefficient must be r ≥ 0.47).
and
- a reproducible and significant increase (i.e. a doubling in the number of revertants for at least one of the tested strains when compared to that of the negative and/or solvent controls) for at least one of the tested concentrations.
A test substance is considered as non-mutagenic in this test system if the above two criteria are not fully met.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: postive for TA1535 from 200µg/plate, TA1537 from 100µg/plate, TA98 from 500µg/plate, TA100 from 250 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 102
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: postive at 500µg/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:
other: postive from 50 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium, other: TA1537, TA98, TA100, TA102
Metabolic activation:
without
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
other: postive for TA1537, TA98 and TA100 from 50µg/plate, TA102 from 100µg/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'.

Applicant's summary and conclusion

Conclusions:
Under these experimental conditions, the test substance 2,6-dichloro-4-trifluoromethylaniline showed mutagenic activity in the Ames test without S9 mix for the 4 strains: TA 1537, TA 98, TA 100 and TA 102. It can be concluded that the test substance is a direct mutagen.