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Genetic toxicity: in vitro

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in vitro gene mutation study in bacteria
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
year of publication was 1984
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Published study, comparable to guideline

Data source

Reference Type:
Primary mutagenicity screening of food additives currently used in Japan.
Ishidate M. Jr, Sofuni T, Yoshikawa K, Hayashi M, Nohmi T, Sawada M and Matsuoka A.
Bibliographic source:
Food Chem. Toxicol., 2: 623-636.
Report date:

Materials and methods

Test guideline
equivalent or similar to guideline
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
E.coli WP2 or S.typhimurium TA 102 were not tested; only duplicates (instead of triplicates) were tested; concentrations tested not mentioned (only maximum concentration), no control data are given in detail, no historical control data are reported
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Reference substance name:
N-butyl acetate
EC Number:
EC Name:
N-butyl acetate
Cas Number:
butyl acetate
Test material form:
other: liquid
Details on test material:
Analytical purity of butyl acetate used in the study was 99%


Target gene:
The usual tester strains used in the Ames test are characterised by mutations at different loci of the histidine operon. Strains TA1535 and TA100, carrying the base substitution mutation hisG46, respond to mutagens that cause single base-pair substitutions. Strain TA1537 contains the histidine frameshift mutation his3076. Reversion of TA1537 to histidine independence requires the deletion of the extra base pair or the possible addition of two base pairs. Strains TA98 contains the histidine frameshift mutation his3052. This is a -1 deletion which may be reverted by either the insertion of a single base pair, or the deletion of 2 adjacent base pairs. All tester strains except strain TA102 contain a uvrB - mutation, which causes loss of the excision repair system, and greatly increases the sensitivity of the test for detecting of many mutagens. Strains TA98 and TA100 were developed by transferring a resistance factor (R-factor) carried on the pKM101 plasmid, to the strain TA1538 and TA1535 respectively. Error prone repair is greatly enhanced in these strains, and the sensitivity of the strains to reversion with a variety of chemical mutagens is greatly increased. Strain TA102 carries the unrevertable deletion hisG8476 in the histidine operon of the bacterial chomosome, but offers the revertable mutation hisG428 on the plasmid pAQ1_ which normally exists in the cells in multiple copies. TA102 was developed to detect mutations at A-T base pairs in contrast to mutations at G-C base pairs in the strains TA1535 and TA100. Finally, all of the strains contain an additional mutation (rfa), which causes the loss of the outer lipopolysaccharide barrier. This increases cell permeability to large organic molecules and greatly decreases the pathogenicity of these organisms.
Species / strain
Species / strain / cell type:
S. typhimurium, other: TA92, TA94, TA98, TA100, TA 1535, TA1537
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
polychlorinated biphenyl (KC-400) induced rat liver S9 mix
Test concentrations with justification for top dose:
Maximum dose: 10 mg/plate (but at least 6 different concentrations tested, no further information)
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
Untreated negative controls:
not specified
Negative solvent / vehicle controls:
not specified
True negative controls:
not specified
Positive controls:
not specified
Positive control substance:
not specified
about 200 substances were tested in this series, including mutagenic and non mutagenic substances
Details on test system and experimental conditions:

- Preincubation period: 20 minutes 37°C
- Exposure duration: 2 days

NUMBER OF REPLICATIONS: 2 plates per strain and dose level; not clearly stated whether negative results were confirmed in a second test
Evaluation criteria:
result positive: number of colonies found was twice the number in the control (exposed to the appropriate solvent or untreated)

Results and discussion

Test results
Species / strain:
S. typhimurium, other: TA92, TA 94, TA 98, TA 100, TA 1535, TA 1537
Metabolic activation:
with and without
tested up to 10 mg/plate
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
not specified
Untreated negative controls validity:
not specified
Positive controls validity:
not specified
Remarks on result:
other: all strains/cell types tested
Migrated from field 'Test system'.

Applicant's summary and conclusion

Interpretation of results (migrated information):

n-butyl acetate did not exert mutagenic activity in the reverse bacterial mutation assay (preincubation assay) with and without metabolic activation.
Executive summary:

Mutagenic activity of n-butyl acetate; purity: 99%, was investigated in Salmonella typhimurium strains TA92, TA 94, TA 98, TA 100, TA 1535 and TA 1537 with (polychlorinated biphenyl (KC-400) induced rat liver S9 mix) and without metabolic activation at concentrations up to 10000 µg/plate using the preincubation method.

The test item did not reveal any mutagenic activity under the conditions tested. According to the authors the appropriate reference mutagens showed distinct positive mutagenic effects.