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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1990
Report Date:
1990

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OTS 798.5265 (The Salmonella typhimurium Bacterial Reverse Mutation Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Physical state: fine white powder
- Purity: 99.19% pure
- Storage condition of test material: Stored in the original container at room temperature and protected from light.

Method

Target gene:
DNA base pairs
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Metabolic activation system:
S-9 mix
Test concentrations with justification for top dose:
50, 158, 500, 1580 and 5000 µg per plate.
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
Controlsopen allclose all
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Positive controls:
yes
Positive control substance:
9-aminoacridine
Positive controls:
yes
Positive control substance:
sodium azide
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Preincubation period: 2 days at 37°C

NUMBER OF REPLICATIONS: triplicate

DETERMINATION OF CYTOTOXICITY
- Method: examination for the presence of a background lawn of non-revertant colonies

Results and discussion

Test results
Key result
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:
no cytotoxicity
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING/SCREENING STUDIES:
Preliminary toxicity test performed with a series of eight different concentrations of test material from 2.5 ug to 5 mg per plate, inoculated with an overnight culture of strain TA 98.
No visible thinning of the background lawn of non-revertant cells was obtained following exposure to ZDBzC. A top exposure level of 5 mg per plate was therefore selected for use in the main assays.

CYTOTOXICITY:
Inhibition of growth, observed as reduction in revertant colony numbers, occurred in all strains on at least one occasion of testing following exposure to ZDBzC at 5000 ug per plate, and in strain TA 100 only with ZDBzC at 1580 ug per plate.

Remarks on result:
other: all strains/cell types tested

Any other information on results incl. tables

Summary of the revertant colony means:

Plate N°

Addition (µg)

S-9mix: + present; - absent

Revertant colony means

TA98(Test 1)

TA98(Test 2)

TA100(Test 1)

TA100(Test 2)

TA1535(Test 1)

TA1535(Test 2)

TA1537(Test 1)

TA1537(Test 2)

1

None; sterility check

 

+

0

0

0

0

0

0

0

0

2

ZDBzC sterility check

5000

-

0

0

0

0

0

0

0

0

3

ZDBzC

5000

+

22

30

42

20

7

10

3

4

4

ZDBzC

1580

+

36

31

73

50

13

12

6

7

5

ZDBzC

500

+

35

33

108

113

13

13

6

7

6

ZDBzC

158

+

34

34

112

112

14

13

8

6

7

ZDBzC

50

+

35

32

111

110

14

15

6

8

8

DMSO

 

+

37

32

110

110

13

13

8

7

9

ZDBzC

5000

-

19

14

34

20

14

8

2

2

10

ZDBzC

1580

-

30

29

64

39

14

14

6

6

11

ZDBzC

500

-

32

33

109

91

13

17

6

7

12

ZDBzC

158

-

35

34

110

109

14

15

7

7

13

ZDBzC

50

-

32

33

106

112

13

16

7

6

14

DMSO

 

-

36

31

110

111

14

16

8

8

15

Benzo(a)pyrene

 

-

31

26

104

102

12

16

6

6

16

Benzo(a)pyrene

 

+

260

393

590

470

846

494

218

171

17

2-Nitrofluorene

 

-

440

909

531

673

644

416

167

146

18

None; 10E-6 dilution of bacterial culture only

 

-

115

113

115

113

114

116

114

113

 

Applicant's summary and conclusion