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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
Study period:
Mar 1984
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1984
Report Date:
1984

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Physical state: solid
- Analytical purity: 98.8%
- Lot/batch No.: 232114080
- Stability under test conditions: yes

Method

Target gene:
not applicable
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:
S9-mix (induced with Aroclor 1254) from rats
Test concentrations with justification for top dose:
0, 125, 250, 500, 1000, 2000 µg/plate per strain
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
no
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Cyclophosphamide, Trypaflavine and 2-Aminoanthracene
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- no Preincubation period
- Exposure duration: 48 h at 37 °C

NUMBER OF CELLS EVALUATED:
minimal culture density: approx. 0.1 x 10 to the power 7 CFU/mL;
approx. maximum: 4 x 10 to the power of 9 CFU/mL

DETERMINATION OF CYTOTOXICITY
performed between 0 to 12500 µg/plate

OTHER: 4 plates per strain and dose, both with and without metabolic activation; same number of vehicle controls;
Evaluation criteria:
A reproducible, dose-related increase in the mutant counts of at least one strain is considered positive , and about double the negative control should be reached
Statistics:
The ANOVA model was used for calculations

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:
For strains TA 98, 1535 and 1537 cytotoxicity was observed at 500 µg/plate and above with and without metabolic activation. For strain TA 100 cytotoxicity was revealed at 2500 µg/plate and above with and without metabolic activation
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
ADDITIONAL INFORMATION ON CYTOTOXICITY:
The two highest dose levels (1000 and 2000 µg/plate) were toxic as evidenced by thinning bacterial lawn and/or reduced revertant count
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Results of cytotoxicity testing (mean of 4 countings)

 

Without S9-mix

With S9-mix

µg/plate

TA100

TA1535

TA98

TA1537

TA100

TA1535

TA98

TA1537

0

100

28

18

6

135

17

33

6

20

100

35

20

5

127

8

35

8

100

80

29

19

4

107

15

29

7

500

62

B

B

B

123

12

24

5

2500

B

B

B

0

37

B

B

B

12500

P

P

P

P

P

P

P

P

2-AA
3 µg

138

20

40

12

1284

344

669

92

Endoxan
145 µg

n.p.

32

n.p.

n.p.

n.p.

458

n.p.

n.p.

Endoxan
290 µg

96

n.p.

n.p.

n.p.

621

n.p.

n.p.

n.p.

Trypaflav.
50 µg

n.p.

n.p.

87

64

n.p.

n.p.

2895

971

B - background growth

P - precipitation

n.p. - not performed

Table 2: Results of mutagenicity testing (mean of 4 countings)

Strain TA 1535

µg / Plate

Mutants / Plate

Bact./ml

- S 9

+ S 9

Exp. +8

0

30±4

14±2

42.2

125

33±5

11±4

41.4

250

20±2

13±3

34.9

500

b**

9±3

38.3

1000

0±0

5±2

6.0 **

2000

0±0

b

0.9 **

Endoxan, 145µg

31±7

205±9

40.7

2-AA,

3 µg

31±6

231±28

37.8

Strain TA 100

0

110±11

132±13

35.4

125

103±15

106±9

28.6

250

90±10

132±11

9.3**

500

41±6

91±21

7.2**

1000

b

70±17

0.9 **

2000

b

25 p±8

0.3 **

Endoxan, 290µg

130±11

398±36

37.4

2-AA,

3 µg

133±18

1017±166

35.2

Strain TA 1537

0

8±3

9±1

32.7

125

3±1

9±3

30.7

250

b

7±1

18.6**

500

3±3

4±2

2.5**

1000

0±0

2±2

0.1 **

2000

0±0

3 p±2

< 0.1 **

T.flavin, 50µg

54±14

336±33

28.3

2-AA,

3 µg

11±3

74±5

34.4

Strain TA 98

0

27±5

26±6

34.8

125

17±3

31±2

31.8

250

9±5

31±7

9.1**

500

b

24±6

2.3**

1000

0±0

25±6

0.2**

2000

0±0

9 p±5

0.2**

T.flavin, 50µg

51±15

816±51

31.4

2-AA, 3µg

43±7

316±50

40.7

**- background

b - bactericidal effect

p - precipitation

The two highest dose levels (1000 and 2000 µg/plate) were toxic as evidenced by thinning bacterial lawn and/or reduced revertant count. Diuron did not increase the number of revertant colonies at any exposure level, with or without activation .No dose-related increase in mutant colonies was observed. The sensitivity of the test system was evidenced by concurrent positive controls.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative
Executive summary:

A reliable genetic toxicity in vitro study was performed according to Ames (1975).Diuron was applied in concentrations of 0, 125, 250, 500, 1000, and 2000 µg/plate. Diuron was not mutagenic in the four tested Salmonella strains up to toxic concentrations both in the presence and absence of a rat metabolic activation system under the conditions employed. (Herbold 1984)