Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1985
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-study equivalent to OECD guideline 471.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1985
Report Date:
1985

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Di-lsobutyl ketone (DIBK)
- Physical state: Colourless, clear liquid
- Analytical purity: 2:1 mixture of 2,6-dimethyl-4-heptanone and 4,6-dimethyl-2-heptanone, water 0.2% maximum
- Lot/batch No.: INDENT 9200/9943

Method

Target gene:
Histidine operon for Salmonella typhimurium, Tryptophan operon for Escherichia coli
Species / strainopen allclose all
Species / strain / cell type:
other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Metabolic activation system:
rat liver microsomal activation system (S9-mix)
Test concentrations with justification for top dose:
31.25, 62.5, 125, 250, 500, 1000, 2000 or 4000µg/mL
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: Solubility of test material
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
TA 1535

Migrated to IUCLID6: 2.5µL/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
TA 1538, TA 98 and TA 100

Migrated to IUCLID6: 10µg/plate
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Potassium dichromate 10µg/plate
Remarks:
E.coli WP2 uvr A pKM 101
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Neutral red 10µg/plate
Remarks:
TA 1537
Details on test system and experimental conditions:
METHOD OF APPLICATION: Preincubation

DURATION
- Preincubation period: 30min
- Exposure duration: 48-72h


NUMBER OF REPLICATIONS: 2


DETERMINATION OF CYTOTOXICITY
- Method: other: colony count

Evaluation criteria:
No data
Statistics:
No data

Results and discussion

Test resultsopen allclose all
Species / strain:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
At concentrations >500µg/mL
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
At concentrations >500µg/mL
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: The test compound, DIBK, produced no evidence of precipitation in the top agar up to 8000µg/ml showing that it was completely miscible in the aqueous test system at these concentrations.

RANGE-FINDING/SCREENING STUDIES: In a preliminary cytotoxicity assay with Salmonella typhimurium TA 100, DIBK was cytotoxic at concentrations above 500µg/ml in both the presence and in the absence of rat liver S9 fraction. Microscopical examination of the background lawn in the bacterial mutation assays showed some variation in cytotoxicity between the strains but, in general agreed with the observations using TA 100.


Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Maximum number of revertants for each strain compared to controls:

 

Maximum number of revertants (dose level [µg/mL])

solvent Control

positive control

DIBK treatment

Strain

With S9

Without S9

With S9

Without S9

With S9

Without S9

TA 98

30

14

331

20

31 (250)

15 (250)

TA 100

88

78

360

81

91 (62.5)

82 (31.25)

TA 1535

12

10

240

546

10 (125)

13 (500)

TA 1537

20

10

58

16

27 (250)

12 (62.5)

TA 1538

27

17

116

15

30 (250)

20 (62.5)

E. coli WP2

33

47

68

216

39 (62.5)

52 (125)

The addition of Diisobutyl Ketone (DIBK) at concentrations up to 4000 µg/ml to cultures of Escherichia coli. WP2 uvr A pkm 101, Salmonella typhimurium TA1535, TA1537, TA1538, TA98 or TA100 did not lead to any increase in the reverse gene mutation rate of these strains either in the presence or in the absence of rat liver S9 fraction under the conditions of this study.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The addition of Diisobutyl Ketone (DIBK) at concentrations up to 4000 µg/ml to cultures of Escherichia coli. WP2 uvr A pkm 101, Salmonella typhimurium TA1535, TA1537, TA1538, TA98 or TA100 did not lead to any increase in the reverse gene mutation rate of these strains either in the presence or in the absence of rat liver S9 fraction under the conditions of this study.