Trisodium bis[3-[[1-(anilinocarbonyl)-2-oxopropyl]azo]-5-chloro-2-hydroxybenzenesulphonato(3-)]cobaltate(3-)

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:

key study

Study period:

From July 21 to September 27, 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

, statistical analysis was not performed

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OTS 798.5265 (The Salmonella typhimurium Bacterial Reverse Mutation Test)

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:

Acid Yellow 204 - Similar Substance 01

IUPAC Name:

Acid Yellow 204 - Similar Substance 01

Test material form:

solid: particulate/powder

Method

Species / strain

Species / strain / cell type:

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

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

20.5761, 61.7284 , 185.1852 ,555.5556 ,1666.6667 ,5000.0000 µg/plate

Vehicle / solvent:

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

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

mitomycin C

Remarks:

without S9

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

yes

Positive control substance:

cyclophosphamide

other: 2-aminoanthracene

Remarks:

with S9

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)
Inoculates from frozen master copies were set up monthly. They were grown in liquid NB-medium overnight and then plated on NB-agar. After incubation, single colonies were taken from the plates, grown overnight in liquid NB-medium and then used for the experiment.

SELECTION AGENT (mutation assays):Colonies were counted electronically with an Artek counter. The results were sent on line to a computer. They were checked on a random basis by the operator.

Control of the genotype of the strains
The characteristics of the strains were checked monthly. Histidine-auxotrophy of the strains was demonstrated by the requirement for 1-histidine. The presence of the rfa character was assayed by the sensitivity for crystal-violet. The deletion of the uvrB gene (strains TA 98, TA 100, TA 1535 and TA 1537) was demonstrated by the sensitivity for UV-light. The Salmonella strains containing the R-factor (TA 98 and TA 100) were additionally checked for ampicillin resistance. Strain TA 102 additionally was checked for tetracycline resistence (presence of multicopy plasmid pAQ1). The presence of the uvr+ gene was demonstrated by the resistence of strain TA 102 against UV-light. Furthermore, all strains were checked for their characteristic
reversion properties with known mutagens (positive controls).

Evaluation criteria:

VALIDITY CRITERIA:
A test is considered acceptable if the mean colony counts of the control values of all strains are within the acceptable ranges and if the results of the positive controls meet the criteria for a positive response. In either case the final decision is based on the scientific judgement of the Study Director.
CRITERIA FOR POSITIVE RESPONSE
The test substance is considered to be mutagenic in this test system if the following conditions are met: At least a reproducible meaningful increase of the mean number of revertants per plate above that of the negative control at any concentration for one or more of the following strains:
S. typhimurium TA 98, TA 100, TA 102, TA 1535 and TA 1537. Generally a concentration-related effect should be demonstrable.

Statistics:

In deviation to the OECD guideline a statistical analysis was not performed. At present the use of statistical methods concerning this particular test system is not generally recommended. No appropriate statistical method is available

Results and discussion

Test results

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Non mutagenic

Executive summary:

In the original experiment carried out without and with metabolic activation, none of the tested concentrations of test item led to an increase in the incidence of histidine-prototrophic mutants by comparison with the negative control.

In the confirmatory experiment performed without and with metabolic activation, again, none of the tested concentrations of test item led to an increase in the incidence of histidine-prototrophic mutants by comparison with the negative control.

Based on the results of these experiments and on standard evaluation criteria, it is concluded that the test substance and its metabolites did not induce gene mutations in the strains of S. typhimurium used.