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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:
2001
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study was conducted in compliance with OECD GLP (1997) regulations.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2001
Report date:
2001

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

Constituent 1
Reference substance name:
MV31 K-Salz
IUPAC Name:
MV31 K-Salz
Test material form:
solid: crystalline
Details on test material:
- Name of test material (as cited in study report): MV31 K-Salz
- Substance type: Mono-constituent
- Physical state: Solid (Grey granules)
- Analytical purity: 88%
- Purity test date: 19 September 2000
- Lot/batch No.: Lot no. 1268147/1-1268154/1
- Expiration date of the lot/batch:31 December 2001
- Stability under test conditions: Guranteed for 4 hours
- Storage condition of test material: Darkness at approximately 20 C in a fume cupboard

Method

Target gene:
Histidine operon
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced rat liver S9-mix
Test concentrations with justification for top dose:
50, 160, 500, 1600 and 5000 ug/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Deionized water
- Justification for choice of solvent/vehicle: Test article solubility
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Positive control substance:
other:
Remarks:
Without S9: TA100 and TA1535: sodium azide, TA1537: 9-aminoacridine, TA98: 2-nitrofluorene, TA102: Mitomycin C. With S9: All strains: 2-aminoanthracene
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation) and preincubation (two independent mutagenicity studies conducted)

DURATION
- Preincubation period: 20-30 minutes
- Exposure duration: 48 hours
- Expression time (cells in growth medium): Approx. 48.5 hours
- Selection time (if incubation with a selection agent): 48.5 hours
- Fixation time (start of exposure up to fixation or harvest of cells): 48 hours

SELECTION AGENT (mutation assays): Histidine minimal agar

NUMBER OF CELLS EVALUATED: Colonies on all plates were counted after exposure.

DETERMINATION OF CYTOTOXICITY
- Method: Bacterial lawn thinning and reduction in the number of colonies
Evaluation criteria:
A test compound is classified as mutagenic if it has either of the following effects: A) It produces at least a 2-fold increase in the mean number of revertants per plate of at least one of the tester strains over the mean number of revertants per plate of the appropriate vehicle control at complete bacterial background lawn or B) it induces a dose-related increase in the mean number of revertants per plate of at least one of the tester strains over the mean number of revertants per plate of the appropriate vehicle control in at least two to three concentrations of the test compound at complete bacterial background lawn. If the test substance does not achieve either of the above criteria, it is considered to show no evidence of mutagenic activity in this system.

Results and discussion

Test results
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
Thinning of bacterial lawns and reduction in the number of colonies was observed in all strains at 1600 or 5000 ug/plate in the presence or absence of S9-mix
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
ADDITIONAL INFORMATION ON CYTOTOXICITY: Thinning of bacterial lawns and reduction in the number of colonies was observed in all strains at 1600 or 5000 ug/plate in the presence or absence of S9-mix
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Thinning of bacterial lawns and reduction in the number of colonies was observed in all strains at 1600 or 5000 ug/plate in the presence or absence of S9-mix
Executive summary:

 The mutagenic potential of the test article (grey granules, purity approx. 88 Fl.%, CASRN 496805-64-2, Lot: 1268147/1-1268154/1) was evaluated in the Bacterial Reverse Mutation Assay with S. typhimurium strains TA98, TA100, TA102, TA1535 and TA1537 in the presence and absence of metabolic activation (S9-mix: Aroclor 1254-induced rat liver).  This study was performed in compliance with OECD GLP (1997) and the German Chemical Law (1999). The study method was based on OECD 471 (1997), US EPA OPPTS 870.5100 (1998), and EEC Directive 92/69 L383A, B.14 (1992). Two independent mutagenicity studies were conducted (one plate incorporation test and one preincubation test. The test article was prepared in deionized water just prior to administration to the cells. In each mutagenicity assay, the test article was tested at up to 5000 ug/plate in each strain in the presence and absence of S9-mix. Strain-specific positive controls were tested in parallel. Each treatment was performed in triplicate. Toxicity (thinning of bacterial lawns and reduction in the number of colonies) was observed in all strains at 1600 or 5000 ug/plate in the presence or absence of S9-mix. No increase in the number of revertants in any strain at any dose in the presence or absence of S9-mix. All criteria for a valid assay were met as described in the protocol. Under the conditions of this study, the test article is not mutagenic in the Bacterial Reverse Mutation Assay in the presence or absence of metabolic activation.