Magnesium divanadium hexaoxide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2011-02-15 to 2011-03-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study reliable without restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted 1997-07-21

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2010-03-22

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Vanadium carbide nitride (V(C,N))

IUPAC Name:

Vanadium carbide nitride (V(C,N))

Constituent 2

Reference substance name:

601-732-9

EC Number:

601-732-9

IUPAC Name:

601-732-9

Constituent 3

Reference substance name:

12069-91-9

Cas Number:

12069-91-9

IUPAC Name:

12069-91-9

Test material form:

other: solid

Details on test material:

- Name of test material (as cited in study report): Vanadium Carbide Nitride
- Physical state: metallic grey solid
- Storage condition of test material: room temperature
- Particle size: 150 - 250 µm (milled)

Method

Target gene:

not applicable

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A pKM 101

Metabolic activation:

with and without

Metabolic activation system:

S9 fraction, prepared from male Sprague-Dawley derived rats, dosed with phenobarbital and 5,6-benzoflavone to stimulate mixed-function oxidases in the liver

Test concentrations with justification for top dose:

Plate incorporation (first test): 5, 15, 50, 150, 500, 1500 and 5000 µg/plate
Preincubation (second test): 50, 150, 500, 1500 and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water (purified in-house by reverse osmosis)
- Justification for choice of solvent/vehicle: vanadium carbide nitride was insufficiently soluble in vehicles compatible with the test system. Water (purified in-house by reverse osmosis) containing 0.15% agar (bacteriological grade) was, therefore, used as the vehicle (suspending agent) for this study.

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water containing 0.15% agar

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

Positive control: without metabolic activation; 2 µg/plate for strains TA100 and TA1535

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water containing 0.15% agar

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

Positive control: without metabolic activation; 50 µg/plate for strain TA1537

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water containing 0.15% agar

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

Positive control: without metabolic activation; 2 µg/plate for strain TA98

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water containing 0.15% agar

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

Remarks:

Positive control: without metabolic activation; 2 µg/plate for strain WP2 uvrA (pKM101)

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water containing 0.15% agar

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene

Remarks:

Positive control: with metabolic activation; 5 µg/plate for strains TA100 and TA1535; 10 µg/plate for strain WP2uvrA (pKM101)

Controls 6

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water containing 0.15% agar

True negative controls:

no

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Remarks:

Positive control: with metabolic activation; 5 µg/plate for strains TA98 and TA1537

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation; first test) and preincubation (second test)

NUMBER OF REPLICATIONS: 3

NUMBER OF CELLS EVALUATED: the appearance of the background bacterial lawn was examined and revertant colonies counted using an automated colony counter (Perceptive Instruments Sorcerer).

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth
Any toxic effects of the test substance would be detected by a substantial reduction in mean revertant colony counts or by a sparse or absent background bacterial lawn.

ACCEPTANCE CRITERIA
For a test to be considered valid, the mean of the vehicle control revertant colony numbers for each strain should lie within or close to the 99% confidence limits of the current historical control range of the laboratory unless otherwise justified by the study director. Also, the positive control compounds must induce an increase in mean revertant colony numbers of at least twice (three times in the case of strains TA1535 and TA1537) the concurrent vehicle controls. Mean viable cell counts in the 10-hour bacterial cultures must be at least 10^9/mL.

Evaluation criteria:

If exposure to a test substance produces a reproducible increase in revertant colony numbers of at least twice (three times in the case of strains TA1535 and TA1537) the concurrent vehicle controls, with some evidence of a positive dose-response relationship, it is considered to exhibit mutagenic activity in this test system. No statistical analysis is performed.
If exposure to a test substance does not produce a reproducible increase in revertant colony numbers, it is considered to show no evidence of mutagenic activity in this test system. No statistical analysis is performed.
If the results obtained fail to satisfy the criteria for a clear “positive” or “negative” response, even after additional testing, the test data may be subjected to analysis to determine the statistical significance of any increases in revertant colony numbers. The statistical procedures used are those described by Mahon et al (1989)* and are usually Dunnett’s test followed, if appropriate, by trend analysis. Biological importance should always be considered along with statistical significance. In general, treatment-associated increases in revertant colony numbers below two or three times the vehicle controls (as described above) are not considered biologically important. It should be noted that it is acceptable to conclude an equivocal response if no clear results can be obtained.
Occasionally, these criteria may not be appropriate to the test data and, in such cases, the study director would use his/her scientific judgement.

*Reference:
MAHON, G.A.T., GREEN, M.H.L., MIDDLETON, B., MITCHELL, I. de G., ROBINSON, W.D. and TWEATS, D.J. (1989) Analysis of data from microbial colony assays in:
KIRKLAND, D.J. (Ed.). UKEMS Sub-committee on Guidelines for Mutagenicity Testing. Report. Part III. Statistical Evaluation of Mutagenicity Test Data, pp.26-65. Cambridge University Press, Cambridge.

Statistics:

The mean number and standard deviation of revertant colonies were calculated for all groups. The “fold-increases” relative to the vehicle controls were calculated in order to compare the means for all treatment groups with those obtained for the vehicle control groups.

Results and discussion

Test results

Test results 1

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:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A pKM 101

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

PLATE INCORPORATION (first test)
No substantial increases in revertant colony numbers over control counts were obtained with any of the tester strains following exposure to vanadium carbide nitride at any concentration up to and including 5000 μg/plate in either the presence or absence of S9 mix.

PREINCUBATION (second test)
No substantial increases in revertant colony numbers over control counts were obtained with any of the tester strains following exposure to vanadium carbide nitride at any concentration up to and including 5000 μg/plate in either the presence or absence of S9 mix.

COMPARISON WITH HISTORICAL CONTROL DATA:
The mean revertant colony counts for the vehicle controls were within or close to the 99% confidence limits of the current historical control range of the laboratory. Appropriate positive control chemicals (with S9 mix where required) induced substantial increases in revertant colony numbers with all strains in all reported tests, confirming sensitivity of the cultures and activity of the S9 mix.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
No evidence of toxicity was obtained following exposure to vanadium carbide nitride.

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

It is concluded that vanadium carbide nitride showed no evidence of mutagenic activity in this bacterial system under the test conditions employed.