1-Naphthalenesulfonic acid, 4-amino-, diazotized, coupled with diazotized 5(or 8)-amino-2-naphthalenesulfonic acid, diazotized 4-nitrobenzenamine and resorcinol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

other: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Study period:

8 July to 23 July, 1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

study conducted on the analogue substance; the read across justification is detailed in section 13. The Reliability of the Source Study is 2 (the study was performed using 5 strains but all of Samonella typhimurium, since followed the OECD 471 of 1983, which was modified later in 1997).

Justification for type of information:

The read across justification is detailed in section 13.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

1983

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Similar Substance 02

IUPAC Name:

Similar Substance 02

Test material form:

solid: particulate/powder

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Additional strain / cell type characteristics:

not specified

Species / strain 2

Species / strain / cell type:

other: S. typhimurium TA 1538

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

10.0; 100.0; 333.3; 1000.0; and 5000.0 µg/plate

Dose selection was based on the results of the pre-experiment. The concentration range covered at least two decadic logarithms. Appropriate dose levels were selected regarding the characteristics of the test item. At least five different concentrations of the test item were tested. The highest dose level should prodece some toxic eggects. The maximum concentration is 5000 µg/plate, unless limited by toxicity or solubility of the test item.
In case the results of pre-experiment were in accordance with the these criteria, these data were reported as part of the main experiments.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water, DMSO

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

without S9, TA 1535 and TA 100

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylene-diamine

Remarks:

without S9, TA1535, TA 1538 and TA 98

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

with S9, TA 1535, TA 1537, TA 1538, TA 98 and TA 100

Details on test system and experimental conditions:

METHOD OF APPLICATION: in Agar
NUMBER OF REPLICATES: 3

Evaluation criteria:

A test item is considered a mutagen if, in strain TA 100, the number of reversions is at least twice as high and in strains TA 1535, TA 1537, TA 1538, and TA 98 it is at least three times higher, compared to the spontaneous reversion rate.
Also, a dose-dependent increase in the number of revertants is regarded as an indication of possibly existing mutagenic potential of the substance regardless of whether the highest dose induced the above described enhancement factors or not.

Statistics:

No valid statistical procedure can be recommended for analysis of data from the bacterial assays at this time

Results and discussion

Test results

Test results 1

Species / strain:

other: S. typhimurium TA 1537, TA 1538 and TA 100

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 98

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

The test item induces point mutations by base pair changes or frameshifts in the genome of the Salmonella typhimurium strains TA1537, TA1538, TA98, and TA100, therefore, the test item is considered to be mutagenic in this reverse mutation (Ames) assay.

Executive summary:

The test item was evaluated for its ability to induce point mutations by base pair change or frameshift in an in vitro bacterial cell reverse mutation assay (Ames test), according to the plate incorporation method of the OECD Guideline 471 (1983). The assay used Salmonella typhimurium strains TA1535, TA1537, TA1538, TA98 and TA100 in two independent experiments, using identical procedures, both with and without liver microsomal activation (S9). Each concentration, including the controls, was tested in triplicate. The test item was tested at five concentrations from 10.0 to 5000 µg/plate. No toxic effects occurred in any of the test groups either in the presence or absence of metabolic activation, as evidenced by a reduction in the number of spontaneous revertants. The plates incubated with the test item showed normal background growth in concentrations up to 5000 ug/plate with and without S9 mix in all strains used. Appropriate reference mutagens were used as positive controls.

Up to the highest investigated dose, a significant and reproducible dose-dependent increase in revertant colony numbers was obtained in S. typhimurium strains TA1537, TA1538, TA98, and TA100. The presence of liver microsomal activation did not influence these findings. However, the positive response in strain TA98 was not reproduced in the independent experiment in the presence of S9 mix. Positive controls showed a distinct increase of induced revertant colonies.

Therefore, the test item is considered to be mutagenic in this reverse mutation (Ames) assay.