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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:
data from handbook or collection of data
Justification for type of information:
Data is from peer reviewed publication

Data source

Reference
Reference Type:
publication
Title:
Studies on the oxidation products from 2,4-diaminotoluene by hydrogen peroxide and their mutagenicities. II
Author:
Tetsushi Watanabe, Mayumi Ono, Teruhisa Hirayama and Shozo Fukui
Year:
1989
Bibliographic source:
Mutation Research, 225 (1989) 15-19

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Principles of method if other than guideline:
Bacterial gene mutation assay was performed to determine the mutagenic nature of p-Nitro-o-toludine
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material: 4-Nitro-o-toludine
- Molecular formula: C7H8N2O2
- Molecular weight: 152.152 g/mol
- Substance type: Organic
Specific details on test material used for the study:
- Name of test material: p-Nitro-o-toludine
- IUPAC name: 2-methyl-4-nitroaniline
- Molecular formula: C7H8N2O2
- Molecular weight: 152.152 g/mol
- Substance type: Organic
- Purity: No data available
- Impurities (identity and concentrations): No data available

Method

Target gene:
Histidine
Species / strain
Species / strain / cell type:
S. typhimurium TA 98
Details on mammalian cell type (if applicable):
Not applicable
Additional strain / cell type characteristics:
not specified
Cytokinesis block (if used):
No data
Metabolic activation:
with and without
Metabolic activation system:
The postmitochondrial fraction (S9) was prepared from the liver of male Sprague-Dawley rats induced with PCB
Test concentrations with justification for top dose:
0 or 1 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: The chemical was soluble in DMSO
Controls
Untreated negative controls:
not specified
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
2-acetylaminofluorene
4-nitroquinoline-N-oxide
Details on test system and experimental conditions:
METHOD OF APPLICATION: in suspension
- Cell density at seeding (if applicable): No data

DURATION
- Preincubation period: No data
- Exposure duration: No data
- Expression time (cells in growth medium): No data
- Selection time (if incubation with a selection agent): No data
- Fixation time (start of exposure up to fixation or harvest of cells): No data

SELECTION AGENT (mutation assays): No data

SPINDLE INHIBITOR (cytogenetic assays): No data

STAIN (for cytogenetic assays): No data

NUMBER OF REPLICATIONS: Triplicate

METHODS OF SLIDE PREPARATION AND STAINING TECHNIQUE USED: No data

NUMBER OF CELLS EVALUATED: No data

NUMBER OF METAPHASE SPREADS ANALYSED PER DOSE (if in vitro cytogenicity study in mammalian cells): No data

CRITERIA FOR MICRONUCLEUS IDENTIFICATION: No data

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; cloning efficiency; relative total growth; other: No data
- Any supplementary information relevant to cytotoxicity: No data

OTHER EXAMINATIONS:
- Determination of polyploidy: No data
- Determination of endoreplication: No data
- Methods, such as kinetochore antibody binding, to characterize whether micronuclei contain whole or fragmented chromosomes (if applicable): No data

- OTHER: No data
Rationale for test conditions:
No data
Evaluation criteria:
The plates were observed for a dose dependent increase in the number of revertants/plate
Statistics:
No data

Results and discussion

Test results
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
No data

Any other information on results incl. tables

Table: Mutagenicity of p-Nitro-o-toluidine in S. typhimurium strain TA98

Sample

Dose (µg/plate

His+revertants/plate

Without

With

p-Nitro-o-toluidine

1

28

39

DMSO

 

14

28

4NQO

0.5

111

 

AAF

5

 

540

Applicant's summary and conclusion

Conclusions:
p-Nitro-o-toludine did not induce gene mutation in Salmonella typhimurium strain TA98 in the presence and absence of S9 metabolic activation system and hence the chemical is not likely to classify as a gene mutant in vitro.
Executive summary:

Bacterial gene mutation assay was performed to determine the mutagenic nature of p-Nitro-o-toludine. The assay was performed using Salmonella typhimurium strain TA98 with and without S9 metabolic activation system. Suspension assay was performed with the test chemical dissolved in DMSO at dose level of 0 or 1 µg/plate. The plates were observed for a dose dependent increase in the number of revertants/plate. p-Nitro-o-toludine did not induce gene mutation in Salmonella typhimurium strain TA98 in the presence and absence of S9 metabolic activation system and hence the chemical is not likely to classify as a gene mutant in vitro.