Pyrimidine

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:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP stud according to OECD guideline.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

1995

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Pyrimidine

EC Number:

206-026-0

EC Name:

Pyrimidine

Cas Number:

289-95-2

Molecular formula:

C4H4N2

IUPAC Name:

pyrimidine

Test material form:

gas under pressure: refrigerated liquefied gas

Details on test material:

- Name of test material: Pyridine

Method

Target gene:

The bacterial strains employed are capable of detecting both induced frame shift (TA 1537, TA 1538 and TA 98) and base substitution (TA 1535 and TA 100) mutagens.
TA 1535 - contains a histidine missense mutation but is also deficient in a DNA repair system (uvr B) and has a defective lipopolysaccharide coat on the cell wall. It is reverted by many agents causing base-pair substitutions, but is not sensitive to frameshift mutagens.
TA 1537 - bears a histidine frameshift mutation. Like TA 1535, it is defective in a DNA repair system and lipopolysaccharide coat. It is sensitive to agents causing frame shift mutations involving insertion or deletion of a single base-pair.
TA 1538 - contains another histidine frameshift mutation. Again it has a defective DNA repair system and lipopolysaccharide coat. It is reverted by agents causing deletion of two adjacent base-pairs (double frame shift mutations).
TA 100 - is the same as TA 1535 but contains a resistance transfer factor conferring ampicillin resistance and increasing sensitivity to some mutagens (plasmid pKM 101). In addition to base-pair substitutions, it is also able to detect certain frame shift mutagens.
TA98 is TA 1538 with the addition of the pKM 101 plasmid. It is reverted by -a variety of mutagens, but not by simple alkylating agents causing base-pair substitutions.

Species / strain

Species / strain / cell type:

S. typhimurium, other: TA 1537, TA 1538, TA 98, TA 1535, TA 100

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

Activated S9 microsomal liver fraction (S-9 mix)

Test concentrations with justification for top dose:

50, 158, 500, 1580 and 5000 µg per plate

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

benzo(a)pyrene

other: 2-aminoanthrazene

Results and discussion

Test results

Species / strain:

S. typhimurium, other: TA 1537, TA 1538, TA 98, TA 1535, TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

RESULTS

- Sterility checks, spontaneous reversion rate and viability checks: The absence of colonies on test item and S-9 mix sterility check plates indicates that these preparations were free of microbial contamination. The total colony counts confirmed the viability and high cell density of the cultures of the individual organisms. The counts recorded on appropriate negative control plates confirmed the characteristically low spontaneous reversion rates of the tester strains and the absence of effects on these rates of purified water inclusion.

- Mutagenic activity of positive control chemicals: Appropriate positive control chemicals (with S-9 mix where required) induced marked increases in revertant colony numbers with all strains, confirming sensitivity of the cultures and activity of the S-9 mix.

- Effect of test item: No increases in revertant colony numbers over control counts were obtained with any of the tester strains following exposure to test item at levels from 50 to 5000 µg per plate.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

The test material did not exhibit any mutagenic activity under the conditions of the test.

Executive summary:

A study was carried out according to EU Method B.13/14 and OECD Guideline 471 (Bacterial Reverse Mutation Assay). The mutagenic potential of the test item in histidine autotrophs of Salmonella typhimurium stains TA 1537, TA 1538, TA 98, TA 1535, TA 100 was assessed. The counts recorded on appropriate negative control plates confirmed the characteristically low spontaneous reversion rates of the tester strains and the absence of effects on these rates of purified water inclusion. Appropriate positive control chemicals (with S-9 mix where required) induced marked increases in revertant colony numbers with all strains, confirming sensitivity of the cultures and activity of the S-9 mix. No increases in revertant colony numbers over control counts were obtained with any of the tester strains following exposure to test item at levels from 50 to 5000 µg per plate. The test material did not exhibit any mutagenic activity under the conditions of the test.