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Toxicological information

Genetic toxicity: in vitro

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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:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1979

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Octan-2-one
EC Number:
203-837-1
EC Name:
Octan-2-one
Cas Number:
111-13-7
Molecular formula:
C8H16O
IUPAC Name:
octan-2-one
Test material form:
liquid

Method

Target gene:
Histidine
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium, other: G46, TA1535, TA100, C3076, TA1537, D3052, TA1538, TA98
Species / strain / cell type:
E. coli, other: WP2, WP2 uvrA-
Metabolic activation:
with and without
Metabolic activation system:
Mixture of rat liver enzymes
Controls
Untreated negative controls:
yes
Positive controls:
yes
Positive control substance:
2-acetylaminofluorene
other: streptozotocin (without met. act.)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

10 mL of minimal agar medium are poured into a square Petri dish and allowed to solidify intno a wedge-shaped layer. 1000 µg/mL mixture of test compound in agar is prepared by adding 10 mL of minimal agar to 0.1 mL of a 100 mg/mL solution of test compound in dimethyl sulfoxide. The solution is poured into the plate. A concentration gradient (100 to 1000 µg/mL) is produced by allowing the compound in the upper wedge to diffuse into the lower layer for 2 hr at room temperature. Three additional plates with concentration ranges of 10 to 100 µg, 1 to 10 µg/mL and 0.1 to 1 µg/mL are prepared. A streaking device consisting of 10 sterile 50 µL pipets is next dipped into suspension of the 10 test strains and allowed to fill by capillary action. The pipets are then touched to the upper edge of the gradient and drawn accoss the plate.

DURATION
- Exposure duration: 48h (37 ºC)

MUTAGENIC EFFECT:
If no mutagenic events occur, a very pale streak of bacterial growth is seen along the inoculation streak. When non-lethal mutagenic events occur, discrete colonies appear in this pale background lawn. The frequency of colony appearance increases along the increasing gradient to a concentration at which maximal mutation occurs. Conversely, frequency decreases along the decreasing gradient to a concentration below which only background lawn is observable. These upper and lower concentrations are reported as the concentration range in which the compound is mutagenic under test conditions.

DETERMINATION OF CYTOTOXICITY
The concentration range over which the test compound is too toxic to permit growth of the auxotroph can be observed by the absence of growth along the application streak (i.e., no background lawn is observable).
Evaluation criteria:
The concentration range over which chemically induced mutant colonies are present is recorded.

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium, other: G46, TA1535, TA100, C3076, TA1537, D3052, TA1538, TA98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
E. coli, other: WP2, WP2 uvrA-
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
The susbstance was determined to be non-mutagenic.
Executive summary:

An in-vitro gene mutation test in bacteria was performed according to a modified Ames test. S. typimurium G46, TA1535, TA100, C3076, TA1537, D3052, TA1538 and TA98, and E.coli WP2 and WP2 uvrA- strains were exposed to concentration gradients of the test item with and without metabolic activation. A plate incorporation method (in agar) was used. A concentration gradient (100 to 1000 µg/mL) was produced by allowing the compound in the upper wedge to diffuse into the lower layer for 2 hr at room temperature. Three additional plates with concentration ranges of 10 to 100 µg, 1 to 10 µg/mL and 0.1 to 1 µg/mL were prepared. The plates were incubated for 48 hr at 37 ºC. The concentration range over which chemically induced mutant colonies were recorded. The test item was determined to be non-mutagenic both with and without metabolic activation under test conditions.