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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:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant, guideline study, available as an unpublished report.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report date:
2015

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
Principles of method if other than guideline:
Each S9 batch is characterized with the mutagens Benzo-(a)-pyrene and 2-aminoanthracene, which require metabolic activation, in tester strain TA100 at concentrations of 5 μg/plate and 2.5 μg/plate, respectively Not the correct amount of 2-aminoanthracene was mentioned in the protocol. This writing error in the protocol had no effect on the results of the study.
GLP compliance:
yes (incl. QA statement)
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Dilithium adipate
EC Number:
242-449-7
EC Name:
Dilithium adipate
Cas Number:
18621-94-8
Molecular formula:
C6H8O4.2Li
IUPAC Name:
dilithium adipate
Test material form:
other: solid
Details on test material:
- Physical state: White powder
- Purity: 100%
- Batch number: FLTF G14058
- Analysis code: A049/99
- Expiration date: 2018-03-06
- Storage of test material: Room temperature in the dark

Method

Target gene:
- Salmonella: +Histidine
- E.Coli: Tryptophan
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Details on mammalian cell type (if applicable):
Not applicable.
Additional strain / cell type characteristics:
not applicable
Species / strain / cell type:
E. coli WP2 uvr A
Details on mammalian cell type (if applicable):
Not applicable.
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced rat liver S9-mix
Test concentrations with justification for top dose:
- Preliminary Toxicity Test: 0, 1.7, 5.4, 17, 52, 164, 512, 1600 and 5000 µg/plate
- Main test experiment one: 52, 164, 512, 1600 and 5000 µg/plate
- Main test experiment two: 52, 164, 512, 1600 and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Milli Q water for test substance and DMSO for positive controls (except sodium azelate which used saline)
- Preparation: Test substance concentrations were used within 2 hours after preparation.
Controlsopen allclose all
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA1535
Negative solvent / vehicle controls:
yes
Remarks:
Milli Q water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene: 2.5 µg/plate
Remarks:
With S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA1537
Negative solvent / vehicle controls:
yes
Remarks:
Milli Q water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene: 2.5 µg/plate
Remarks:
With S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA98
Negative solvent / vehicle controls:
yes
Remarks:
Milli Q water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene: 1 µg/plate
Remarks:
With S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA100
Negative solvent / vehicle controls:
yes
Remarks:
Milli Q water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene: 1 µg/plate in direct plate assay and 5 µg/plate in preincubation assay
Remarks:
With S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of WP2uvrA
Negative solvent / vehicle controls:
yes
Remarks:
Milli Q water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene: 15 µg/plate
Remarks:
With S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA1535
Negative solvent / vehicle controls:
yes
Remarks:
Milli Q water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: Sodium azide: 5 µg/plate
Remarks:
Without S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA1537
Negative solvent / vehicle controls:
yes
Remarks:
Milli Q water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: ICR 191: 2.5 µg/plate and 2-nitrofluorene: 10 µg/plate
Remarks:
Without S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA98
Negative solvent / vehicle controls:
yes
Remarks:
Milli Q water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-nitrofluorene: 10 µg/plate
Remarks:
Without S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA100
Negative solvent / vehicle controls:
yes
Remarks:
Milli Q water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Methylmethanesulfonate: 650 µg/plate
Remarks:
Without S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of WP2uvrA
Negative solvent / vehicle controls:
yes
Remarks:
Milli Q water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-nitroquinoline N-oxide: 10 µg/plate
Remarks:
Without S9 mix
Details on test system and experimental conditions:
METHODS OF APPLICATION
- Experiment 1: In agar (plate incorporation)
- Experiment 2: Pre-incubation

DURATION
- Preincubation period for bacterial strains: 30 minutes
- Exposure duration: 48 hours
- Expression time (cells in growth medium): Not applicable

NUMBER OF REPLICATIONS: Triplicate plating.

DETERMINATION OF CYTOTOXICITY
- Method: The revertant colonies were counted automatically with the Sorcerer Colony Counter. Plates with sufficient test article precipitate to interfere with automated colony counting were counted manually. Evidence of test article precipitate on the plates and the condition of the bacterial background lawn were evaluated when considered necessary, macroscopically and/or microscopically by using a dissecting microscope.
To determine the toxicity, the reduction of the bacterial background lawn, the increase in the size of the microcolonies and the reduction of the revertant colonies were observed.
Evaluation criteria:
Acceptability of the assay
A Salmonella typhimurium reverse mutation assay and/or Escherichia coli reverse mutation assay is considered acceptable if it meets the following criteria:
a) The vehicle control and positive control plates from each tester strain (with or without S9-mix) must exhibit a characteristic number of revertant colonies when compared against relevant historical control data generated at WIL Research Europe.
b) The selected dose range should include a clearly toxic concentration or should exhibit limited solubility as demonstrated by the preliminary toxicity range-finding test or should extend to 5 mg/plate.
c) No more than 5% of the plates are lost through contamination or some other unforeseen event. If the results are considered invalid due to contamination, the experiment will be repeated.

Data evaluation and statistical procedures
A test substance is considered negative (not mutagenic) in the test if:
a) The total number of revertants in tester strain TA100 is not greater than two (2) times the concurrent control, and the total number of revertants in tester strains TA1535, TA1537, TA98 or WP2uvrA is not greater than three (3) times the concurrent control.
b) The negative response should be reproducible in at least one follow up experiment.
A test substance is considered positive (mutagenic) in the test if:
a) The total number of revertants in tester strain TA100 is greater than two (2) times the concurrent control, or the total number of revertants in tester strains TA1535, TA1537, TA98 or WP2uvrA is greater than three (3) times the concurrent control.
b) In case a repeat experiment is performed when a positive response is observed in one of the tester strains, the positive response should be reproducible in at least one follow up experiment.
Statistics:
No formal hypothesis testing was done. Standard deviation was determined.

Results and discussion

Test resultsopen allclose all
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Remarks:
Tested up to maximum recommended dose of 5000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
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 nor precipitates, but tested up to recommended limit concentrations
Remarks:
Tested up to maximum recommended dose of 5000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Results: All bacterial strains showed negative responses over the entire dose range, i.e. no significant dose-related increase in the number of revertants in two independently repeated experiments. Based on the results of this study it is concluded that the substance is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay.
Precipitate: Precipitation of the substance on the plates was not observed at the start or at the end of the incubation period in all tester strains.
Toxicity: There was no reduction in the bacterial background lawn and no biologically relevant decrease in the number of revertants at any of the concentrations tested in all tester strains in the absence and presence of S9-mix.
Mutagenicity: In the direct plate test and the pre-incubation test, no increase in the number of revertants was observed upon treatment with the test substance under all conditions tested.
Negative controls: The negative control values were within the laboratory historical control data ranges.
Positive controls: The strain-specific positive control values were within the laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly, except the response for TA1537 in the absence of S9-mix, second experiment. The purpose of the positive control is as a reference for the test system, where a positive response is required to check if the test system functions correctly. Since the value was more than 3 times greater than the concurrent solvent control values, this deviation in the mean plate count of the positive control had no effect on the results of the study.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Dose range finding test - Mutagenic response in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay

Mean number of revertant colonies/3 replicate plates (±S.D.) with one strain of Salmonella typhimurium and one Escherichia coli strain

 

Without S9

With S9

Dose

TA100

WP2uvrA

TA100

WP2uvrA

Positive control

862 ± 37

1574 ± 37

1395 ± 94

311 ± 6

Solvent control

102 ± 11

28 ± 6

82 ± 11

41 ± 10

1.7

88 ± 6

33 ± 7

93 ± 20

35 ± 8

5.4

81 ± 10

26 ± 6

105 ± 7

36 ± 12

17

89 ± 15

27 ± 9

102 ± 11

33 ± 10

52

104 ± 18

31 ± 4

104 ± 9

38 ± 8

164

95 ± 3

26 ± 7

105 ± 10

37 ± 7

512

99 ± 20

31 ± 1

95 ± 8

42 ± 10

1600

98 ± 16

33 ± 13

103 ± 18

39 ± 6

5000

87 ± 14 *

28 ± 9 *

93 ± 0 *

39 ± 7 *

* No precipitate and normal bacterial background lawn

Table 2: Experiment 1 - Mutagenic responnse in Salmonella typhimurium reverse mutation assay - Direct plate assay

Mean number of revertant colonies/3 replicate plates (±S.D.) with different strains of Salmonella typhimurium

 

Without S9

With S9

Dose

TA 1535

TA 1537

TA 98

TA 1535

TA 1537

TA 98

Positive control

851 ± 29

421 ± 62

949 ± 12

284 ± 16

454 ± 42

1121 ± 42

Solvent control

20 ± 6

16 ± 5

18 ± 2

15 ± 5

5 ± 0

28 ± 5

52

20 ± 10

8 ± 3

16 ± 2

15 ± 6

14 ± 6

39 ± 3

164

23 ± 5

8 ± 2

17 ± 8

12 ± 2

11 ± 1

31 ± 9

512

17± 2

6 ± 6

12 ± 3

17 ± 5

10 ± 6

32 ± 7

1600

18 ± 2

9 ± 2

19 ± 4

25 ± 2

10 ± 5

29 ± 8

5000

12 ± 0 *

11 ± 3 *

17 ± 4 *

18 ± 4 *

9 ± 4 *

30 ± 1 *

* No precipitate and normal bacterial background lawn

Table 3: Experiment 2 - Mutagenic response in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay - Pre-incubation assay

Mean number of revertant colonies/3 replicate plates (±S.D.) with different strains of Salmonella typhimurium and one Escherichia coli strain

 

Without S9

With S9

Dose

TA 1535

TA 1537

TA 98

TA 100

WP2uvra

TA 1535

TA 1537

TA 98

TA 100

WP2uvra

Positive control

766 ± 52

56 ± 5

1003 ± 56

682 ± 64

169 ± 22

126 ± 9

160 ± 8

432 ± 26

2266 ± 183

399 ± 21

Solvent control

17 ± 3

10 ± 6

16 ± 4

103 ± 13

33 ± 3

8 ± 2

12 ± 4

28 ± 3

115 ± 17

35 ± 5

52

17 ± 2

7 ± 3

19 ± 2

119 ± 19

26 ± 8

10 ± 5

13 ± 5

29 ± 3

126 ± 10

43 ± 16

164

16 ± 4

8 ± 4

19 ± 1

107 ± 10

27 ± 7

10 ± 5

12 ± 6

28 ± 3

110 ± 7

35 ± 5

512

11 ± 6

13 ± 2

15 ± 7

103 ± 11

30 ± 7

10 ± 5

9 ± 6

23 ± 2

109 ± 13

28 ± 5

1600

15 ± 4

9 ± 2

19 ± 7

103 ± 7

23 ± 1

10 ± 5

13 ± 11

33 ± 9

103 ± 5

42 ± 6

5000

17 ± 2 *

9 ± 6 *

18 ± 5 *

107 ± 11 *

29 ± 6 *

10 ± 5 *

15 ± 5 *

25 ± 4 *

112 ± 15 *

28 ± 12 *

* No precipitate and normal bacterial background lawn

 

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Based on the results of this study, it is concluded that dilithium adipate is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay.
Executive summary:

The in vitro mutagenicity of dilithium adipate was assessed in a GLP-compliant Bacterial Reverse Mutation Test, following OECD guideline 471 (WIL 2015). S. typhimurium and E. coli strains were treated with suspensions of dilithium adipate using both the Ames plate incorporation and pre-incubation methods at five dose levels in triplicate, both with and without the addition of a rat liver homogenate metabolising system. The vehicle and positive controls confirmed the sensitivity of the assay and the efficacy of the S9 -mix.

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