Dimethyl sulphate

Genetic toxicity: in vitro

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

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

Test material information

Constituent 1

Reference substance name:

Dimethyl sulphate

EC Number:

201-058-1

EC Name:

Dimethyl sulphate

Cas Number:

77-78-1

Molecular formula:

C2H6O4S

IUPAC Name:

dimethyl sulfate

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 / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Additional strain / cell type characteristics:

not specified

Species / strain 2

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

Controls

Controls 1

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

Controls 2

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

Controls 3

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 results

Test results 1

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

Test results 2

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.