Registration Dossier

Toxicological information

Genetic toxicity: in vivo

Currently viewing:

Administrative data

Endpoint:
in vivo mammalian germ cell study: gene mutation
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions.

Data source

Reference
Reference Type:
publication
Title:
Genotoxicity of cobalt compounds on Drosophila.
Author:
Tripathy NK, Patnaik RC, Panigrahi SK, Kalra S
Year:
2006
Bibliographic source:
J Ecobiol 18(3): 287-295

Materials and methods

Principles of method if other than guideline:
Eggs from wild type Oregon R flies were collected for 8 h. Second and 3rd instar larvae were collected and treated with 5ml of the desired concentrations of test compounds used for rehydration of 1.5 g of instant food. Concurrent control experiments were also run where the same age larvae were exposed to the solvent alone for similar duration. The male flies developed from these larvae were individually mated to 3 Basc females for 3 days and the resulting Oregon R/Basc F1 females were mated with their Basc/Y sibs at a ratio of 1:1 in individual vials. After 3-4 days the F2 cultures were screened for the presence of wild type males. The absence of males with wild type eyes in at least 20 flies (males and females taken together) in the F2 cultures indicated the induction of sex-linked recessive lethals.
GLP compliance:
not specified
Type of assay:
Drosophila SLRL assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Source: manufactured by Central Drug house, New Delphi
- Name of test material (as cited in study report): cobalt acetate
- Molecular formula (if other than submission substance): Co(CH3CO2)2 4H2O
- Molecular weight (if other than submission substance): 249.1 g/mol

Test animals

Species:
Drosophila melanogaster
Strain:
other: Oregon R
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 2nd and 3rd instar larvae

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 25±1°C

Administration / exposure

Route of administration:
oral: feed
Vehicle:
- Vehicle(s)/solvent(s) used: no data
- Concentration of test material in vehicle: 1.0, 2.5, 5.0 mM
Details on exposure:
DIET PREPARATION
- Mixing appropriate amounts with (Type of food): 1.5 g of instant food from Carolina Biological Supply Co., Burlington Nc, USA, rehydrated with the different concentrations of the test compound dissolved in 5 ml of the solvent
Duration of treatment / exposure:
48 and 72 hours
Frequency of treatment:
continuously
Post exposure period:
none
Doses / concentrations
Remarks:
Doses / Concentrations:
1.0, 2.5, 5.0 mM
Basis:
nominal in diet
No. of animals per sex per dose:
At least 20 flies (males and females together) of F2 generation
Control animals:
yes, concurrent vehicle

Examinations

Tissues and cell types examined:
phenotype of eyes
Evaluation criteria:
Absence of males with wild type eyes in at least 20 flies (males and females together) in the F2 cultures.
Statistics:
following Kastenbaum and Bowman (1970)

Results and discussion

Test results
Sex:
male
Genotoxicity:
positive
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
not specified
Positive controls validity:
not specified

Any other information on results incl. tables

The experiments to test the genotoxicity of the test substance in the male germ line cells were repeated, and since the lethal frequencies did not differ significantly in the two experiments, the data were pooled. Following larval exposures to different concentrations of cobalt acetate, the frequencies of induction of recessive lethals were positive only at 2.5 mM concentration.

Since they were induced only at 2.5 mM and not at 5.0 mM concentration of cobalt acetate, it indicates that the larvae must have escaped the food supplemented with the high dose of the compound since it could be repellent.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): positive