Registration Dossier

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:
1991
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
: only 4 strains tested
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): benzothiazole
- Analytical purity: 97.4 %
- Purity test date: May 21, 1991
- Lot/batch No.: 90 B 0521
- Other: Sample No.: 105488/1990; Product No.:680982

Method

Target gene:
His operon
Species / strain
Species / strain / cell type:
other: S. typhimurium TA 98, TA 100, TA 1535, TA 1537
Metabolic activation:
with and without
Metabolic activation system:
S9-mix
Test concentrations with justification for top dose:
8, 40, 125, 200, 250, 500, 1000, 2000, 4000, 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethylene glycol dimethylether (EGDE) for benzothiazole and DMSO for the positive controls
- Justification for choice of solvent/vehicle: for EGDE: sufficient evidence was available in the literature (Maron and Ames, 1983)
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
Migrated to IUCLID6: 10 µg per plate were used without S9 mix
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: nitrofurantoin: 0.2 µg per plate were used without S9 mix
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-nitro-1,2-phenylene diamine: 0.5 (in TA 98) and 10 µg per plate (in TA 1537) were used without S9 mix
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene: 3 µg per plate were used with S9 mix
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hours
- Expression time (cells in growth medium): 17 hours
- Selection time (if incubation with a selection agent): 48 hours


DETERMINATION OF CYTOTOXICITY
- Method: other: reduction in background growth; marked and dose-dependent reduction in the mutant count per plate and the titer was determined

Evaluation criteria:
A reproducible and dose-related increase in mutant counts of at least one strain is considered to be a positive result. For TA 1535, TA 100 and TA 98 this increase should be about twice the amount of negative controls, whereas for TA 1537, at least a threefold increase should be reached. Otherwise, the result is evaluated as negative.
Statistics:
no data

Results and discussion

Test results
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:
cytotoxicity
Remarks:
at 1000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: other: S. typhimurium TA 98, TA 100, TA 1535, TA 1537
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Summary of results with benzothiazole

S9 mix

TA 1535

TA 100

TA 1537

TA 98

Without

Negative

Negative

Negative

Negative

With

Negative

Negative

Negative

Negative

Summary of mean values without S9 mix

With or without S9-Mix

Test substance concentration

(µg/plate)

Mean number of revertant colonies per plate

(average of 4 parallel testings)

Base-pair substitution type

Frameshift type

TA 1535

TA 100

TA 1537

TA 98

-

0

17

102

8

32

-

8

12

107

9

38

-

40

16

117

9

33

-

200

17

115

11

32

-

1000

10

107

13

32

-

5000

/

20

5

2

Positive

controls

- S9

Name

Na-azid

NF

4-NPDA

4-NPDA

Concentrations

(µg/plate)

 10

 0.2

 10

 0.5

Number of colonies/plate

470

312

46

103

 

TA 1535

TA 100

TA 1537

TA 98

-

0

14

65

8

29

-

125

13

60

10

25

-

250

15

66

7

23

-

500

12

52

9

22

-

1000

12

61

9

20

-

2000

12

60

6

15

-

4000

9

36

3

9

Positive

controls

- S9

Name

Na-azid

NF

4-NPDA

4-NPDA

Concentrations

(µg/plate)

 10

 0.2

 10

 0.5

Number of colonies/plate

610

241

46

68

Na-azid = sodium azide

NF = nitrofurantoin

4 -NPDA = 4 -nitro-1,2 -phenylene diamine

Summary of mean values with S9 mix

With or without S9-Mix

Test substance concentration

(µg/plate)

Mean number of revertant colonies per plate

(average of 4 parallel testings)

Base-pair substitution type

Frameshift type

TA 1535

TA 100

TA 1537

TA 98

+

0

26

151

16

39

+

8

19

144

13

37

+

40

15

143

13

45

+

200

15

150

13

44

+

1000

16

131

8

30

+

5000

9

29

6

4

Positive

controls

+ S9

Name

2-AA

2-AA

2-AA

2-AA

Concentrations

(µg/plate)

 3

 3

 3

 3

Number of colonies/plate

132

615

117

234

 

TA 1535

TA 100

TA 1537

TA 98

+

0

22

152

17

45

+

125

24

123

17

36

+

250

19

149

16

41

+

500

17

130

17

36

+

1000

18

109

18

38

+

2000

16

88

17

34

+

4000

8

82

9

21

Positive

controls

+ S9

Name

2-AA

2-AA

2-AA

2-AA

Concentrations

(µg/plate)

 3

Number of colonies/plate

234

762

81

731

2-AA = 2-aminoanthracene

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative no classification required
Executive summary:

Gahlmann (Bayer AG), 1991

The mutagenic activity of benzothiazole was investigated in a bacterial gene mutation assay conducted comparable to OECD-guideline 471 with acceptable restrictions (only 4 strains used). The plate incorporation method was performed with Salmonella typhimurium TA98, TA 100, TA1535 and TA1537 both in presence and absence of a metabolic activator at 8, 40, 125, 200, 250, 500, 1000, 2000, 4000, 5000 µg benzothiazole per plate. Under these conditions no mutagenic activity was reported in strains TA 98, TA 100, TA 1535, or TA1537. Therefore no classification is required.