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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:
no data available
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: No metabolic activation used, no historical data.

Data source

Reference
Reference Type:
publication
Title:
Relative sensitivities of forward and reverse mutation assays in Salmonella typhimurium
Author:
Skopek, T.R.
Year:
1978
Bibliographic source:
Proc. Natl. Acad. Sci. 75, 4465-4469

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
: no metabolic activation used. Not enough test concentrations.
GLP compliance:
no
Remarks:
Study was conducted before implementation of GLP.
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): Dimethyl sulphate
- Substance type: technical product
- Physical state: liquid, volatile
- Analytical purity: not stated
- no further significant details stated

Method

Target gene:
not applicable
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
not specified
Species / strain / cell type:
S. typhimurium TA 1538
Additional strain / cell type characteristics:
not specified
Metabolic activation:
without
Test concentrations with justification for top dose:
100, 200, 300 uM
Vehicle / solvent:
- Phosphate buffered saline
- no further significant details stated
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
7,12-dimethylbenzanthracene
Remarks:
with metabolic activation

Migrated to IUCLID6: 40, 60 and 80 µM
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
without metabolic activation

Migrated to IUCLID6: 5, 10 and 15 mM
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
without metabolic activation

Migrated to IUCLID6: 2.5, 5.0 and 7.5 mM
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar

DURATION
- Preincubation period: 1 hour
- Exposure duration: 1 hour in a 37°C dry-air incubator without shaking.

NUMBER OF REPLICATIONS: The compounds were delivered to each of duplicate flasks.

EVALUATION: After treatment, the cells were centrifuged, washed and plated on a minimal E agar with biotin and no histidine to determine the his+ revertant fraction. The fraction of revertant colonies in relation to the clones on toxicity plates were calculated.

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth:
An aliquot of cell suspension was added to 0.9 ml of top agar, and the resulting mixture was plated on a minimal E agar plate containing biotin and 5 mM histidine to determine toxicity.
Evaluation criteria:
no data
Statistics:
not madatory for this test system

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
without
Genotoxicity:
positive
Remarks:
see table 1 under "any other information on results"
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
without
Genotoxicity:
positive
Remarks:
see table 1 under "any other information on results"
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
No further data
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1 Induced mutant fractions of DMS:

Strain

DMS concentrations

100 µM

200 µM

300 µM

TA1535

100

190

420

TA1537

110

220

2100

TA1538

0.6

7.8

30

TA98

0

20

83

TA100

110

340

870

Table 2: Minimal concentration to which each strain is sensitive

Strain

Concentration [µM]

TA 1535

4.3

TA1537

11

TA 1538

180

TA98

140

TA100

32

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive without metabolic activation

DMS induces a substential increase in revertant colony numbers in reverse mutation assay under the described test conditions.