Registration Dossier

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:
supporting study
Study period:
1980
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Scientific work conducted in accordance with generally accepted scientific principles, possibly with incomplete reporting or methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference
Reference Type:
publication
Title:
Inhalation exposure in Drosophila mutagenesis assays: experiments with aliphatic halogenated hydrocarbons, with emphasis on the genetic activity profile of 1,2-dichloroethane.
Author:
Kramers, P.G.N., Mout. H.C.A., Bissumbhar. B., Mulder. C.R.
Year:
1991
Bibliographic source:
Mutation Research 252(1), 17-33.

Materials and methods

Principles of method if other than guideline:
Flies were kept in flasks containing approximately 8 ml of standard Drosophila melanogaster medium into which the desired amount of test material (non-specified purity, DBM) was injected through a rubber septum. The SLRL tests were carried out with treated adult male Drosophila melanogaster flies of a wild-type strain (Berlin K) that were 1-3 days old at the beginning of treatment. The treated males were mated with 3 virgin females of the Base strain and subsequently re-mated every 2 or 3 days with 3 fresh virgins up to a maximum of 5 such mating periods (broods). After short-term exposure, this mating procedure allows the separate sampling of germ-cell populations treated at different stages of their development.
GLP compliance:
no
Type of assay:
Drosophila SLRL assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Dibromomethane
EC Number:
200-824-2
EC Name:
Dibromomethane
Cas Number:
74-95-3
Molecular formula:
CH2Br2
IUPAC Name:
dibromomethane
Details on test material:
non-specified purity, DBM

Test animals

Species:
Drosophila melanogaster
Sex:
male/female

Administration / exposure

Vehicle:
standard Drosophila medium
Details on exposure:
Groups of 20-25 flies were kept in 1160 ml flasks containing approximately 8 ml of standard Drosophila medium into which the desired amount of test material (non-specified purity, DBM) was injected through a rubber septum. When treatment times exceeded 48 hours, the vessels were flushed every 2 or 3 days (fresh medium was given in the case of adult treatment) and a new dose of test material was introduced. The SLRL tests were carried out with treated adult male Drosophila melanogaster flies of a wild-type strain (Berlin K) that were 1-3 days old at the beginning of treatment. The treated males were mated with 3 virgin females of the Base strain and subsequently re-mated every 2 or 3 days with 3 fresh virgins up to a maximum of 5 such mating periods (broods). After short-term exposure, this mating procedure allows the separate sampling of germ-cell populations treated at different stages of their development.

Examinations

Tissues and cell types examined:
For the detection of SLRL mutations, the standard scheme was performed.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative

Any other information on results incl. tables

The results given at the table below demonstrate the number of mortalities per number of chromosomes test in each mating period (brood) and in total.

Frequencies of sex-linked recessive mortalities after treatment with DBM

 

Expose. Time

Conc. (mg/m3)

Brood A

nl/nchr#   %l

Brood B

nl/nchr  %l

Brood C

nl/nchr  %l

Brood D

nl/nchr  %l

Brood E

nl/nchr  %l

Brood A-E

nl/nchr  %l

DBM

6h

60.2

0/396      0

1/386  0.26

1/396  0.25

0/394     0

0/392     0

2/1964  0.1

#Number of lethal/number of chromosomes tested

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
DBM is not mutagenic when evaluated in the Drosophila melanogaster sex-linked recessive lethal test.
Executive summary:

In order to detect the occurrence of mutations, both point mutations and small deletions, in the germ line of an insect, the sex-linked recessive lethal (SLRL) test using Drosophila melanogaster was conducted. The inhalation route was selected by analogy to the human exposure situation.

Groups of 20-25 flies were kept in 1160 ml flasks containing approximately 8 ml of standard Drosophila medium into which the desired amount of test material (non-specified purity, DBM) was injected through a rubber septum. When treatment times exceeded 48 hours, the vessels were flushed every 2 or 3 days (fresh medium was given in the case of adult treatment) and a new dose of test material was introduced. The SLRL tests were carried out with treated adult male Drosophila melanogaster flies of a wild-type strain (Berlin K) that were 1-3 days old at the beginning of treatment. The treated males were mated with 3 virgin females of the Base strain and subsequently re-mated every 2 or 3 days with 3 fresh virgins up to a maximum of 5 such mating periods (broods). After short-term exposure, this mating procedure allows the separate sampling of germ-cell populations treated at different stages of their development. Upon long-term exposure, however, one may expect accumulation of damage according to the specific sensitivities of the stages through which the cells have proceeded during treatment. For the detection of SLRL mutations, the standard scheme was performed.

DBM is not mutagenic when evaluated in the Drosophila melanogaster sex-linked recessive lethal test.