ALFERROCK

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Screening of Environmental Chemical Mutagens by the Rec-Assay System with Bacillus subtilis

Author:

Kada, T.

Year:

1980

Bibliographic source:

Chemical Mutagens 1980, pp 149-173

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

Different types of DNA damage are subjected to cellular recombination repair, thus recombinationless bacteria are usually more sensitive than the wild type bacteria. After incubation with the test compound the length of the inhibition zones are measured and compared between the wild type and mutant strain for assessing the mutagenic potential of the test compound AlCl3.

GLP compliance:

not specified

Type of assay:

Bacillus subtilis recombination assay

Test material

Test material information

Constituent 1

Reference substance name:

Aluminium chloride

EC Number:

231-208-1

EC Name:

Aluminium chloride

Cas Number:

7446-70-0

IUPAC Name:

aluminum trichloride

Details on test material:

- Name of test material (as cited in study report): AlCl3

Method

Target gene:

Rec system (rec45 arg try)

Species / strain

Species / strain / cell type:

bacteria, other: Bacillus subtilis

Details on mammalian cell type (if applicable):

- Type and identity of media:
B-2 broth: (meat wet extract, 10 g; polypeptone dry powder, 10 g; NaCl, 5 g; water, 1000 ml; pH adjusted to 7.0.
Broth agar: 15g/L of agar added to the B-2 broth growing medium

Test concentrations with justification for top dose:

A test concentration is not mentioned, but it is mentioned for assaying samples of unknown potency:
For assaying samples of unknown potency, it is recommended that the assay be initiated with doses as high as possible using saturated solutions of each drug in a solvent. A negative result can be concluded under these conditions. By repeating the assays using solutions of lower drug concentrations, the clearest positiveness can be detected at a drug concentration where the inhibition zone for Rec+ bacteria is very close to zero.

Vehicle / solvent:

Besides water, available solvents are dimethylsulfoxide (DMSO), acetone, and ethyl acetate, which scarcely inhibit either Rec+ or Rec- bacteria, though no-drug "control" experiments must be carried out.

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

not specified

Details on test system and experimental conditions:

Strains H17 Rec+ and M45 Rec- are grown overnight in B-2 broth. One milliliter 50% glycerol (wt./vol.) is added to 3 ml fully grown bacterial broth culture, and the mixture is stored at -80 °C. On the day of the experiments, each culture is thawed and streaked on the "dry" surface of broth agar, and the paper disk containing the test drug is positioned. The plates are kept at 4-5 °C for 24 hr, then incubated at 37 °C for about 20 hr. The length of the inhibition zone is then measured.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

bacteria, other: Bacillus subtilis

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

True negative controls validity:

not specified

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

not applicable

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

not determined

Test results 3

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

not applicable

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

not determined

Test results 4

Species / strain:

S. typhimurium TA 98

Metabolic activation:

not applicable

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

not determined

Test results 5

Species / strain:

S. typhimurium TA 100

Metabolic activation:

not applicable

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

not determined

Test results 6

Species / strain:

S. typhimurium TA 102

Metabolic activation:

not applicable

Genotoxicity:

not determined

Cytotoxicity / choice of top concentrations:

not determined

Applicant's summary and conclusion

Conclusions:

Under the described test conditions, the test compound AlCl3 is considered to be negative in the Bacillus subtilis Rec Assay.

Executive summary:

In a Bacillus subtilis Rec Assay, the strain H17 Rec+ (rec+ arg try) and M45 Rec- (rec45 arg try) were exposed to aluminum chloride. Only minor information were presented about the test compound concentration, the solubility and the used solvent/vehicle. Moreover, it is not clear, if postive controls were used during the test . Due to the simplicicity of the assay and the well described protocol of Rec Assay it can nevertheless be stated, that under the decribed test conditions, the test compound aluminum chloride is considered to be negative in the Bacillus subtilis Rec Assay.