Registration Dossier

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: Guideline study under GLP conditions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Batch GSF 4-20079

Method

Target gene:
TA1537: his C3076; da-; uvrß- frame shift mutations
TA1538: his ; da-; uvrß- frame shift mutations
TA 98: his D 3052; rfa-; uvrß-; R-factor frame shift mutations
TA1535: his G 46; rfa-; uvrß- base-pair substitutions
TA 100; his G 46 ; rfs-, uvrß- base-pari substitutions
Species / strainopen allclose all
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
S9-homogenate
Species / strain:
S. typhimurium TA 1538
Additional strain characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
S9-homogenate
Test concentrations with justification for top dose:
1µg, 10µg, 100µg, 1000µg and 5000µg
Vehicle:
Water
Controlsopen allclose all
Negative controls:
yes
Remarks:
Water
Solvent controls:
yes
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
fro TA 1535 and TA 100
Negative controls:
yes
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
for TA 1537
Negative controls:
yes
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
TA 1538 and TA 98
Evaluation criteria:
A test substance is considered mutagenic if there is a reproducibly increasing dose-response curve of induced colonies for at least three concentrations. The minimal criteria for a positive response are two- to threefold increase in the number of revertants (at least 10 colonies) over the sponaneous number for the stains TA 1535, TA 1537, TA 1538 and TA 98, and a 50% increase for TA 100. Less pronounced effects without dose-resposne releationship are reported as equivocal results (+_)in the table of results (summary) and are considered to be biologically not relevant. More over, to avoid a misinterpretation of the mutagenicity data, the positive response should not be obtained only at concentratons near to toxic dose levels.

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:
no, but tested up to precipitating concentrations
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
no, but tested up to precipitating concentrations
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
The test substance Pyrazole DHE has no mutagenicity potential in concentration till 5000µg per plate in the testes species
Executive summary:

The study was perfomed to investigate the potential of Pyrazole DHE to induce gene mutations according to the OECD Guideline 471.

The strains were exposed on minimal agar platesto a range of concentrationsof the test substance (up to 5000µg/ plate) both in the presents and absence of an exogenous metabolic activation system. The testet strain were TA 1535, TA 1538, TA 1538, Ta 98, and TA 100.

Results:

The mean numbers of spontaneous revertant colonies on untreated and /or solvent treated plates (= negative controls values or background revertant counts) are within the normal range previously esthablished in our laboratory and agree with the values from the literature. Similary, the results with the positive control substances confrim the sensitivity of the tester strains as well as the activity of the metabolizing system.

In this Ames reversion the test substance "DA 010894" (Pyrazole DHE) did not induce any significant increase in the number of revertant colonies on the plates, with any of the bacterial tester strains used, either in the presents or absence of S9 -mix, at concentratons ranging from 1 to 5000 µg per plate.

Some groth inhibiting or toxic effects, detected as significant decreases in the number of spontaneous revertants per plate and/or presence of a sparse bacterial background lawn were observed with TA 1537 and TA 98, without S9 -mix, and TA 100 with S9 -mix, at the highest dose leves of 3000/5000µg per plate.

Therefore it can be concluded that the Test Substance "DA 010894" (Pyrazole DHE was not mutagenic in the Ames reversion assay!