Isobutyraldehyde

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:

supporting 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 1

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Reference 2

Reference Type:

publication

Title:

Salmonella Mutagenicity Tests: II. Results From Testing of 270 Chemicals

Author:

Mortelmans, K. et al.

Year:

1986

Bibliographic source:

Environ. Mutagen. 8, Suppl. 7, 1-119

Reference 3

Reference Type:

publication

Title:

Salmonella mutagenicity tests: V. Results from the testing of 311 chemicals

Author:

Zeiger E et al.

Year:

1992

Bibliographic source:

Environ. Mol. Mutagen . 19 (Suppl . 21), 2-141

Materials and methods

Principles of method if other than guideline:

Method: other: Haworth, S. et al.: Environ. Mutagen. 5, Suppl. 1, 3-142

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Isobutyraldehyde

EC Number:

201-149-6

EC Name:

Isobutyraldehyde

Cas Number:

78-84-2

Molecular formula:

C4H8O

IUPAC Name:

2-methylpropanal

Details on test material:

- Name of test material (as cited in study report): Isobutyraldehyde
- Purity: 98%

Method

Species / strain

Species / strain / cell type:

other: Salmonella typhimurium TA97, TA98, TA100, TA102, TA1535, TA1537, and TA104

Metabolic activation:

with and without

Metabolic activation system:

Aroclor induced rats and hamster S-9 mix (5, 10 or 30%)

Test concentrations with justification for top dose:

0 - 10000 µg/plate depending on strain used

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

sodium azide

other: 4-nitro-o-phenylenediamine and 2-aminoanthracene

Remarks:

See any other information on materials and methods incl. tables

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 minutes
- Exposure duration: 48 hours

NUMBER OF REPLICATIONS: 3 plates per dose level

DETERMINATION OF CYTOTOXICITY
- Method: Appearance of his- pinpoint colonies, reduced numbers of revertant colonies per plate, or thinning or absence of the bacterial lawn.

Evaluation criteria:

A positive response is defined as a reproducible, dose-related increase in histidine-independent (revertant) colonies in any one strain/activation combination. An equivocal response is defined as an increase in revertants that is not dose related, not reproducible, or not of sufficient magnitude to support a determination of mutagenicity. A negative response is obtained when no increase in revertant colonies is observed following chemical treatment. There was no minimum percentage or fold increase required for a chemical to be judged positive or weakly positive.

Results and discussion

Test results

Species / strain:

other: Salmonella typhimurium TA104, TA97, TA98, TA100, TA102 TA1535, and TA1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

In the report of the NTP the results of TA104 with rat S9 mix is considered to be equivocal. However, Mortelmans et al does not consider the results to be equivocal. Based on the only slight increase in revertants the results cannot be considered to be equivocal, but are negative.