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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:
03 May 2001 to 07 May 2001
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study was not conducted under GLP conditions.

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:
yes
Remarks:
The study was performed with the strains TA 98 and TA 100 only
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Reference substance name:
Laurylmercaptobytyronitril
IUPAC Name:
Laurylmercaptobytyronitril
Details on test material:
- Name of test material (as cited in study report): Laurylmercaptobytyronitril
- Substance type: Mono-constituent
- Physical state: Liquid
- Analytical purity: 99%
- Purity test date:
- Lot/batch No.: P 5889001
- Expiration date of the lot/batch: 01 April, 2002
- Storage condition of test material: At room temperature

Method

Target gene:
Histidine operon
Species / strain
Species / strain / cell type:
other: S. typhimurium TA 98 and TA 100
Metabolic activation:
with and without
Metabolic activation system:
S9 rat liver microsomal fraction
Test concentrations with justification for top dose:
3, 10, 33, 100, 333, 1000, 2500, and 5000 ug/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Ethanol
- Justification for choice of solvent/vehicle: Solubility properties and its relative non-toxicity to the bacteria.
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
Ethanol
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
This positive control was utilized in S. typhimurium strains TA 98 and TA 100 with metabolic activation.
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
Ethanol
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
This positive control was utilized in S. typhimurium strain TA 100 without metabolic activation.
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
Ethanol
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-nitro-o-phenylene-diamine, 4-NOPD
Remarks:
This positive control was utilized in S. typhimurium strain TA 98 without metabolic activation.
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium

DURATION
- Preincubation period: 4 hours
- Exposure duration: 48 hours
- Expression time (cells in growth medium): 52 hours
- Selection time (if incubation with a selection agent): 48 hours
- Fixation time (start of exposure up to fixation or harvest of cells): 48 hours

SELECTION AGENT (mutation assays): L-Histidine

NUMBER OF CELLS EVALUATED: All plates were evaluated for an increase in revertant colonies.
Evaluation criteria:
A test item is considered positive if a dose related increase in the number of revertants or a biologically relevant increase for at least one test concentration is induced.

Results and discussion

Test results
Species / strain:
other: S. typhimurium
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: None
- Effects of osmolality: None
- Evaporation from medium: None
- Precipitation: No precipitation was observed at any dose.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Based on the results of the study, the test article is not mutagenic in a screening Ames Assay.
Executive summary:

The mutagenic potential of the test article was evaluated in a screening Bacterial Reverse Mutation Assay with S. typhimurium strains TA 98 and TA 100 in the presence and absence of a metabolic activation system (S9 mix). The study was not performed in compliance with GLP regulations. The test method was based on OECD 471 (1997) but only S. typhimurium strains TA 98 and TA 100 were utilized. The test article was dissolved in ethanol for dosing at 3, 10, 33, 100, 333, 1000, 2500, and 5000 ug/plate and all strains were tested in triplicate. Separate experiments were performed in the presence and absence of metabolic activation with S9 mix. Strain specific positive controls and vehicle controls were tested in parallel. No toxic effects were seen in the study. No reduction in the number of colonies occurred in the presence or absence of metabolic activation. No increase in the number of revertant colonies was seen in any strain in the presence or absence of metabolic activation. Controls performed as expected. Based on the results of the study, the test article is not mutagenic in the screening Ames Assay in the presence or absence of metabolic activation.

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