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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
June 1988
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study, according to OECD471.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report Date:
1988

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: wax
Details on test material:
identity of the test material: octyl phosphonic acid

Method

Species / strain
Species / strain / cell type:
other: Salmonella typhimurium TA 100, TA 1535, TA 1537, TA 1538, TA 98 and E. coli W2uvrA
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
S9 mix
Test concentrations with justification for top dose:
Experiment I: 4, 20, 100, 500, 2500 or 10000 µg/plate
Experiment II: 4, 20, 100, 500, 2500 or 5000 µg/plate
Vehicle / solvent:
DMSO
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
not specified
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
2-nitrofluorene
sodium azide
benzo(a)pyrene
other: N-Methyl-N-nitro-N-nitrosoguanidine, 2-Aminoanthracene
Details on test system and experimental conditions:
Toxicity experiments and dose range finding:
The first experiment (I) was performed with all tester strains using three plates per dose to get information on mutagenicity and toxicity for calculation of an approriate dose range. A reduced rate of spontaneously occuring colonies as well as visible thinning of the bacterial lawn were used as indicator for toxicity. Thinning of the bacterial lawn was controlled microscopically.
In combination with the second experiment, toxicity testing was performed as follows:
0.1 mL of the different dilutions of the test compound were thoroughly mixed with 0.1 mL of 10exp(-6) dilution of the overnight culture of TA100 and plate with Histidine and Biotin rich top agar (3 plates per dose). The solvent control is compared with the number of colonies per plate in the presence of the tst compound. Results are given as a ration of these values (=surviving fraction).

Mutagenicity test:
Top agar is prepared for the Salmonella strains by mixing 100 mL Agar (0.6 % Agar, 0.5% NaCl) with 10 mL of a 0.5 mL Histidine-biotin solution. Wthi E. coli Histidine is replaced by Tryptophan (2.5 mL, 0.5. mM). The following ingredients are added to 2 mL of molten top agar at 45°C:
0.1 mL of an overnight nutrient broth culture of the bacterial tester strain, 0.1 mL test compound solution, 0.5 mL S9 mix or buffer.
After mixing, the liquid is pooured into a Petridish with minimal Agar (1.2 % Agar, Vogel-Bonner E medium with 2% Glucose). After incubation for approx. 48 hours at 37°C in the dark, colonies are counted. Two independent exeriments were performed.

Positive controls:
Positive control plates were included for each strain. the following substances were used as positive controls:

a) without S9 mix
Sodium azide: TA100, TA 1535
9-Aminocridine: TA1537
2-Nitrofluorene: TA98, TA1538
N-Methyl-N-nitro-N-nitrosoguanidine (MNNG): E. coli WP2uvrA

b) with S9 mix
Benzo[a]pyrene: TA98, TA100, TA1535, TA1537, TA1538, E. coli WP2uvrA
2-Aminoanthracene: TA98, TA100, TA1535, TA1537, TA1538, E. coli WP2uvrA
Evaluation criteria:
No data
Statistics:
not madatory

Results and discussion

Test resultsopen allclose all
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
at 2500 µg/plate and higher
Vehicle controls validity:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
other: TA 98, TA 100, TA 1535, TA 1537, TA 1538
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
at 500 µg/plate and higher
Vehicle controls validity:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Controls:
Control plates (background control and positive controls) gave the expected number of colonies.

Toxicity test:
The test compound was tested at doses of 4 to 10000 µg/plate and proved to be toxic to the most of the bacterial strains at doses of 500 or 2500 µg/plate. Thinning of the bacterial lawn and a reduction in the number of colonies have been observed at these doses. Visible precipitation of the test compound on the plates has been observed at 10000 µg/plate.

Mutagencity test:
The test item did not cause a significant increase in the number of revertant colonies with any of the tester strains either in the absence or presence of S9 mix. No dose dependent effect was obtained.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The structural analogue octyl phosphonic acid did not cause any increase in the number of revertant colonies with any of the tester strains in absence or presence of S9 mix.
Executive summary:

The structural analogue octyl phosphonic acid was tested for mutagenicty with the strains TA 100, TA 1535, TA 1537, TA 1538, TA 98 of Salmonella typhimurium and Escherichia coli WP2uvrA (for read across justification please refer to attached document).

The mutagnicity studies were conducted in the absence and in the presence of a metabolising system derived from rat liver homogenate. A dose range of 6 different doses from 4 to 5000 µg/plate was used.

Control plates without mutagen showed that the number of spontaneous revertant colonies was similar to that described in the literature. All positive control comounds gave the expected increase in the number of revertant colonies.

Toxicity: The test item proved to be toxic to the most of the bacterial strains at 500 µg/plate. 5000 µg/plate was chosen as top dose level for the mutagenicity study.

Mutagenicity: In the absence of the metabolic activation system the test compound did not show a dose dependent increase in the number of revertants in any of the bacterial strains. Also in the presence of metabolic activation system, treatment of the cells with

octyl phosphonic acid did not result in relevant increases in the number of revertant colonies.

It can be stated that the structural analogue octyl phosphonic acid is not mutagenic in these bacterial test systems either with or without metabolic activation.