Registration Dossier

Diss Factsheets

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Well documented guideline study. Purity of the test substance is not stated. Only four test strains were used instead of five (E.coli WP2 strains or S. typhimurium TA102 should be used in addition acc. to OECD guideline).

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report date:
1989

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
Only minor deviations from the test guideline: 4 bacteria strains were tested instead of 5 strains.
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Disodium sulphide
EC Number:
215-211-5
EC Name:
Disodium sulphide
Cas Number:
1313-82-2
Molecular formula:
Na2S
IUPAC Name:
disodium sulfide
Test material form:
solid: crystalline
Details on test material:
- Name of test material (as cited in study report): Natrium sulfid

Method

Target gene:
not applicable
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Metabolic activation system:
S-9 mix (rat, Aroclor 1254 induced)
Test concentrations with justification for top dose:
0, 20, 100, 500, 2500 and 5000 µg/plate (standard plate test) and
0, 4, 20, 100, 500 and 2500 µg/plate (preincubation test)
Vehicle / solvent:
DMSO
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 10µg of 2-aminoanthracene
Remarks:
with metabolic activation; all strains
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 5 µg of N-ethyl-N-nitro-N-nitrosoguanidine
Remarks:
without metabolic activation; strains TA100 and TA1535
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 10µg of 4-nitro-o-phenylendiamine
Remarks:
without metabolic activation; strain TA98
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 100µg of 9-aminoacridine chloride monohydrate
Remarks:
without metabolic activation; strain TA1537
Details on test system and experimental conditions:
METHOD OF APPLICATION
in agar (plate incorporation); preincubation

DURATION
- Preincubation period: 20 minutes, 37°C
- Exposure duration: 48 hours, 37°C, in the dark

SELECTION AGENT
minimal glucose agar

NUMBER OF REPLICATIONS
Triplicate

DETERMINATION OF CYTOTOXICITY
Method: relative total growth
Evaluation criteria:
In general, a substance to be characterized as positive in the Ames test has to fulfill the following requirements:
- doubling of the spontaneous mutation rate (control)
- dose-response relationship
- reproducibility of the results
Statistics:
Not required for the Ames test.

Results and discussion

Test results
Key result
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: Reduced his- background growth was observed at doses >=2500µg/plate using TA1535, TA1537 and TA98. With TA100 there was only a slight decrease in the number of his+ revertants in the preincubation test at 2500µg/plate.
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid

Any other information on results incl. tables

Mutagenicity

Standard plate test

- without S-9 mix: No increase of his+ revertants in all tester strains

- with S-9 mix: No increase of his+ revertants in all tester strains

Preincubation test

- without S-9 mix: No increase of his+ revertants in all tester strains

- with S-9 mix: No increase of his+ revertants in all tester strains

Toxicicty

A bacteriotoxic effect (reduced his- background growth, decrease in the number of his+ revertants) was observed depending on the experiment and test conditions at doses >= 2500 µg/plate using TA 1535, TA 1537 and TA 98.

With TA 100 there was only a slight decrease in the number of his+ revertant in the preincubation test without S-9 mix at 2500 µg/plate.

Applicant's summary and conclusion

Conclusions:
According to the results of the study, the test substance sodium sulfide is not mutagenic in the Ames test under the experimental conditions chosen here.
Executive summary:

The substance Natriumsulfid was tested for mutagenicity in the Ames test:

- Strains: TA 1535, TA 100, TA 1537, TA 98

- Dose range: 20 µg - 5000 µg/plate (SPT); 4 µg - 2500 µg/plate (PIT)

- Test conditions: Standard plate test (SPT) and preincubation test (PIT) both with and without metabolic activation (rat liver S-9 mix).

- Solubility: Complete solubility of the test substance in DMSO.

Toxicity

A bacteriotoxic effect was observed using TA 1535, TA 1537 and TA 98 depending on the test conditions at doses >= 2500 µg/plate.

Using TA 100 only a slight decrease in the number of his+ revertants was observed in the PIT without S-9 mix at 2500 µg/plate.

Mutagenicity

An increase in the number of his+ revertants was not observed both in the standard plate test and in the preincubation test either without S-9 mix or after the addition of a metabolizing system.

Conclusion

According to the results of the present study, the test substance Natriumsulfid is not mutagenic in the Ames test under the experimental conditions chosen here.