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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:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment.

Data source

Reference
Reference Type:
publication
Title:
Mutagenic activity of 42 coded compounds in the Salmonella/microsome assay.
Author:
Richold M and Jones E.
Year:
1981
Bibliographic source:
Prog. Mutat. Res. 1: 314-322

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
Strain
Principles of method if other than guideline:
5 strains (S.typhimurium): TA1535, TA1537, TA1538, TA98, TA100
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Other name = Ethylenethiourea (ETU)

Method

Species / strain
Species / strain / cell type:
other: TA1535, TA1537, TA1538, TA98 and TA100
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
arochlor-induced liver microsomal fraction (10%)
Test concentrations with justification for top dose:
5, 50, 500, and 5000 µg/plate
Vehicle / solvent:
DMSO
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Details on test system and experimental conditions:
The mutation test was performed using the procedure described by Ames et al. (1975). Each compound was tested initially at four concentrations with serial tenfold dilutions being made from the top concentration. Triplicate plates were used at each dose.
Evaluation criteria:
A positive response is claimed of the increase in the number of revertant colonies is at least 2-2.5 times the control with some evidence of a dose response relationship.
Statistics:
no data

Results and discussion

Test results
Species / strain:
other: TA1535, TA1537, TA1538, TA98 and TA100
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
at all concentrations
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
The highest dose level used in the mutation study was that concentration which caused slight toxicity.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table of results: Mean number revertant colonies per plate

ETU dose (µg/plate)

TA1535

TA1537

TA1538

TA98

TA100

S9

-

+

-

+

-

+

-

+

-

+

5000

8

12

3

5

8

14

50

50

55

27

500

8

11

5

4

9

12

50

59

52

27

50

8

8

5

8

5

9

54

67

37

22

5

8

12

6

5

6

12

47

58

36

21

Solvent (DMSO)

9

12

5

6

10

11

57

62

39

21

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Negative result of ETU mutagenicity.
Executive summary:

Forty-two coded compounds were submitted for testing in the Ames Salmonella/Microsome assay using S. typhimurium strainsTA1535, TA1537, TA1538, TA98,and TA100.The test was performed in the presence and absence of metabolic activation provided by a supplemented Aroclor-induced Iiver microsomal fraction (S9 mix). ETU gave negative results at all concentrations in all strains.