Methanesulphonyl chloride

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Methanesulphonyl chloride

EC Number:

204-706-1

EC Name:

Methanesulphonyl chloride

Cas Number:

124-63-0

Molecular formula:

CH3ClO2S

IUPAC Name:

methanesulfonyl chloride

Details on test material:

Test article name : Methane sulfonyl chloride
Cas n°: 124-63-0
Origin: Elf Aquitaine Production
Batch no. : 96000478
Purity: 99.85%.

Method

Target gene:

Histidine reversion

Species / strain

Species / strain / cell type:

S. typhimurium, other: strains: TA 98, TA 100, TA 1535, TA 1537, and TA 102

Details on mammalian cell type (if applicable):

checked for appropriate genetic markers (rfa mutation, R factor)

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254-induced rat liver post-mitochondrial fraction (S-9) assayed for its ability to metabolize ethidium bromide and cyclophosphamide to bacterial mutagens.

Test concentrations with justification for top dose:

Plate incorporation assay: 0, 40, 200, 1000, and 5000 µg per plate, +/- S9 activation
Pre-incubation assay: 1000, 2000, 3000, 4000, 5000, 7500 and 10000 µg/plate, +/-S9 activation

Vehicle / solvent:

- Solvent: acetone
- Justification for choice of solvent/vehicle: it as been demontrated that MSC is stable in acetone in these test conditions (Gonzalez C (1994). Formation de MMS par reaction du CMS avec le methanol. Testing laboratory: Elf Aquitaine Production, CAT. Report no.: 94.173. Owner company: Arkema France. Report date: 1994-11-08.)

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: With S9: 2-aminoanthracene 5.0 µg/plate (at lest 1 strain). Without S9, TA98, 2-nitrofluorene 5.0 µg/plate; TA100, TA1535, Sodium azide 2.0 µg/plate; TA1537, 9-aminoacridine 50 µg/plate; TA102, glutaraldehyde 25.0 µg/plate .

Remarks:

All positive controls were diluted in dimethyl sulfoxide (DMSO) except for sodium azide and glutaraldehyde, which were diluted in water

Details on test system and experimental conditions:

PRELIMINARY TOXICITY ASSAY
The preliminary toxicity assay was used to establish the dose range over which the test article would be assayed: 0, 40, 200, 1000, and 5000 µg per plate, +/- S9 activation in TA100 strain

MUTAGENICITY ASSAY
Methane Sulfonyl Chloride was assayed for mutation in five
histidine-requiring strains (TA98, TA100, TA1535, TA1537 and TA102) of Salmonella typhimurium, both in the absence and in the presence of metabolic activation by an Aroclor
1254-induced rat liver post-mitochondrial fraction (S-9), in two separate experiments.

TEST PROCEDURE
Plate incorporation method:
One half (0.5) milliliter of S9 or Sham mix, 100 µL of tester strain and 0.02 mL of vehicle or test article dilution were added to 2.5 mL of molten selective top agar at 46°C. After vortexing, the mixture was overlaid onto the surface of minimal bottom agar.
Preincubation method:
One-half (0.5) milliliter of S9 or sham mix, 100 µL of tester strain and 0.02 mL of vehicle or test article dilution were added to culture tubes. fter vortexing, these mixtures were incubated with shaking for 60 A minutes at 37°C. Following the preincubation, 2.5 mL of selective top agar was added to each tube and the mixture was vortexed and overlaid onto the surface of minimal bottom agar.

Three plates/dose were used for the test substance and the positive controls, 5 plates for the negative control.

Evaluation criteria:

- Acceptance criteria
The assay was considered valid if the following criteria were met:
1) the mean negative control counts fell within the normal ranges,
2) the positive control chemicals induced clear increases in revertant numbers confirming discrimination between different strains, and an active S-9 preparation
3) no more than 5 % of the plates were lost through contamination or some other unforeseen event.

- Evaluation criteria
The test article was considered to be mutagenic if:
1) the assay was valid
2) Dunnett's test gave a significant response (p < 0.01), and the data set showed a significant dose-correlation
3) the positive responses were reproducible.

Statistics:

Dunnett's test

Results and discussion

Test results

Species / strain:

S. typhimurium, other: strains: TA 98, TA 100, TA 1535, TA 1537, and TA 102

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

other: >= 7500 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TOXICITY ASSAYS
An initial toxicity range-finder experiment was carried out in strain TA100 only, using final concentrations of Methane Sulfonyl Chloride at 8, 40, 200, 1000 and 5000 µg/plate, plus solvent and positive controls. Following these treatments, and those in Experiment 1 performed using the same dose range, no clear evidence of toxicity was observed.

Following Experiment 2 treatments performed using pre-incubation methodology, a majority of the test doses were affected in some way by toxicity.
During repeat treatments of these strains in the presence of S-9 and using standard plate-incorporation methodology, signs of toxicity were observed with strain TA102 at the two highest treatment concentrations. Experiment 2 treatments in the absence of S-9 also gave rise to signs of toxicity in a majority of the strains at the higher treatment concentrations.

MUTAGENICITY ASSAYS
Methane Sulfonyl Chloride treatments of strain TA1535 both in the absence and in the presence of S-9, resulted in statistically significant and reproducible increases in revertant numbers (when data were analysed at the 1 % level using Dunnett's test), that were considered to be clear evidence of a mutagenic effect.
Methane Sulfonyl Chloride treatments of strain TA100 in the absence and presence of S-9 also gave rise to statistically significant and reproducible increases in revertant numbers. Although the magnitude of these increases was markedly smaller than those observed with strain TA1535, it was considered that these increases in revertant numbers provided further evidence of Methane Sulfonyl Chloride mutagenic activity.

No treatment of strains TA98, TA1537 and TA102 either in the absence or presence of metabolic activation resulted in a reproducible increase in revertant numbers sufficient to be considered as evidence of mutagenic activity.

The mean numbers of revertant colonies on negative control plates all fell within acceptable ranges, and were significantly elevated by positive control treatments.

Remarks on result:

other: strain/cell type: TA 1535 and TA 100

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
positive

Methane Sulfonyl Chloride did induce mutation in Salmonella typhimurium strain TA1535, and exhibited evidence of weak mutagenic activity in Salmonella typhimurium strain TA100, both in the absence and presence of a rat liver metabolic activation system (S-9), when tested under the conditions
employed for this study, which included treatments at concentrations up to 10000 µg/plate.

Executive summary:

In an test performed according to the OECD guidelines #471 and GLP, which included treatments at concentrations up to 10000 µg/plate, methanesulfonyl chloride (purity 99.8%) was assayed for mutation in five histidine-requiring strains (TA98, TA100, TA1535, TA1537 and TA102) of Salmonella typhimurium, both in the absence and in the presence of metabolic activation by an Aroclor 1254-induced rat liver post-mitochondrial fraction (S-9).

Methanesulfonyl chloride induced mutagenic activity on TA 1535 and exhibited evidence of weak mutagenic activity in TA 100 strains, both with and without metabolic activation.