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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 from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1999-11-25 to 2000-01-17
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP and guideline compliant study. Read-across was performed with lithium hydroxide. Please refer to IUCLID section 13 for read-across justification.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report date:
2000

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
July 1997
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Lithium hydroxide
EC Number:
215-183-4
EC Name:
Lithium hydroxide
Cas Number:
1310-65-2
Molecular formula:
LiOH
IUPAC Name:
Lithium hydroxide
Test material form:
other: solid

Method

Target gene:
The Salmonella typhimurium histidine (his) reversion system measures his- -> his+ reversions. The Salmonella typhimurium strains are constructed to differentiate between base pair (TA 1535, TA 100) and frameshift (TA 1537, TA 98) mutations. The Escherichia coli WP2 uvrA (trp) reversion system measures trp– -> trp+ reversions. The Escherichia coli WP2 uvrA detect mutagens that cause other base-pair substitutions (AT to GC).
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
S9 Mix
Test concentrations with justification for top dose:
Lithium hydroxide was tested in concentrations of 3, 10, 33, 100, 333, 1000, 3330 and 5000 µg/plate with and without S9 mix.
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
TA 1535 without S9

Migrated to IUCLID6: NaN3
Positive control substance:
9-aminoacridine
Remarks:
TA 1537 without S9

Migrated to IUCLID6: 9AA
Positive control substance:
other: daunomycine (DA)
Remarks:
TA 98 without S9
Positive control substance:
methylmethanesulfonate
Remarks:
TA 100 without S9

Migrated to IUCLID6: MMS
Positive control substance:
4-nitroquinoline-N-oxide
Remarks:
WP2uvrA without S9
Positive control substance:
other: 2-aminoanthracene (2-AA)
Remarks:
TA 1537, TA 1535, TA 98, TA 100, E. coli WP2uvrA with S9
Details on test system and experimental conditions:
The test substance was dissolved in Milli-Q-water. The test substance was ground and the stock solution was filter(0.22 µm)-sterilized. Test substance concentrations were prepared directly prior to use.

Range finding study:
Lithium hydroxide was tested in the tester strains TA 100 and WP2uvrA with concentrations of 3, 10, 33, 100, 333, 1000, 3330 and 5000 µg/plate in the absence and in the presence of S9 mix.

Mutation assay:
Based on the results of the dose range finding study, lithium hydroxide was tested up to concentrations of 5000 µg/plate in the absence and in the presence of S9-mix in two mutation experiments. The first mutation experiment was performed with the strains TA 1535, TA 1537 and TA 98; the second mutation experiment was performed with the strains TA 1535, TA 1537, TA 98, TA 100 and WP2uvrA.
Evaluation criteria:
A test substance is considered negative (not mutagenic) in the test if:
a) The total number of revertants in any tester strain at any concentration is not greater than two times the solvent control value, with or without metabolic activation.
b) The negative response should be reproducible in at least one independently repeated experiment.

A test substance is considered positive (mutagenic) in the test if:
a) It induces a number of revertant colonies, dose related, greater than two-times the number of revertants induced by the solvent control in any tester strains, either with or without metabolic activation.
However, any mean plate count of less than 20 is considered to be not significant.
b) The positive response should be reproducible in at least one independently repeated experiment.
Statistics:
Not indicated

Results and discussion

Test resultsopen allclose all
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
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
GENOTOXICITY:
Please refer to tables 1 and 2, which are presented under Sect. "Remarks on results including tables and figures"
- without metabolic activation: No increase in the number of revertants/plate observed
- with metabolic activation: No increase in the number of revertants/plate observed

CYTOTOXICITY:
No reduction of the bacterial background lawn was observed in all dose levels tested.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Experiment 1

Mutagenic response of lithium hydroxide in the Salmonella typhimurium reverse mutation assay and the Escherichia coli reverse mutation assay:

 Dose (µg/plate)

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

 

TA 1535

TA 1537

TA 98

TA 100

WP2uvrA

Without S9-mix

positive control

219±33

435±100

371±39

466±22

172±32

solvent control

12±6

7±3

16±3

65±2

9±2

 

3

 

 

 

77±13

12±3

10

 

 

 

72±7

11±3

33

 

 

 

79±8

8±2

100

12±1

7±5

18±3

74±8

12±3

333

15±1

7±1

16±4

65±7

7±3

1000

14±3

4±2

19±3

80±8

9±2

3330

11±3

8±3

12±4

77±13

5±2

5000

12±1

6±2

12±5

77±11

4±1

With S9-mix[1]

positive control

296±23

703±22

1346±230

1199±176

237±37

solvent control

14±6

6±2

26±3

90±10

11±3

 

3

 

 

 

96±4

12±3

10

 

 

 

99±5

12±4

33

 

 

 

95±9

9±3

100

11±3

6±3

31±4

78±11

12±2

333

15±1

4±1

27±9

101±5

10±1

1000

18±7

9±1

26±6

83±12

11±3

3330

15±6

5±1

25±3

86±14

7±4

5000

14±2

4±1

22±3

65±1

4±1

Solvent control: 0.1 ml Milli-Q water

[1]The S9-mix contained 5% (v/v) S9 fraction

Experiment 2

Mutagenic response of lithium hydroxide in the Salmonella typhimurium reverse mutation assay and in the escherichia coli reverse mutation assay:

Dose (μg/plate)

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

 

TA 1535

TA 1537

TA 98

TA 100

WP2uvrA

Without S9-mix

positive control

195±2

287±105

642±125

608±24

696±16

solvent control

10±1

4±2

15±4

69±10

8±1

 

100

12±4

4±2

13±2

79±13

10±1

333

8±3

4±3

16±7

68±10

8±3

1000

12±5

5±2

15±2

70±7

11±2

3330

11±4

4±2

10±4

60±11

6±1

5000

7±1

5±2

11±3

64±8

7±3

With S9-mix[1]

positive control

203±14

367±45

551±25

709±131

70±8

solvent control

9±1

3±2

23±3

67±6

11±5

 

100

10±4

3±1

23±3

84±14

12±3

333

8±2

3±3

25±4

70±8

12±2

1000

9±4

6±3

22±6

68±11

7±2

3330

11±5

3±2

14±4

49±6

7±2

5000

5±3

3±2

13±2

54±8

3±1

Solvent control: 0.1 ml Milli-Q water

[1]The S9-mix contained 5% (v/v) S9 fraction

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative with and without metabolic activation

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

A bacteria reverse mutation test with lithium bromide was not available. Consequently, read-across was applied using study results obtained from lithium hydroxide as it is a characteristically similar compound.

Lithium hydroxide was tested in the Salmonella typhimurium reverse mutation assay according to OECD Guideline 471. The test was performed with four histidine-requiring strains of Salmonella typhimurium (TA 1535, TA 1537, TA 100 and TA 98) and in the Escherichia coli reverse mutation assay with a tryptophane-requiring strain of Escherichia coli WP2uvrA in two independent experiments. Lithium hydroxide was tested up to concentrations of 5000 µg/plate in the absence and presence of S9 -mix. Lithium hydroxide did not precipitate on the plates at this dose level. The bacterial background lawn was not reduced at all concentrations tested. Reduction in the number of revertants was observed in the tester strain TA 1535, TA 98, TA 100 and WP2uvrA. Lithium hydroxide did not induce a dose-related, two-fold, increase in the number of revertant (His+) colonies in each of the four tester strains (TA 1535, TA 1537, TA 98 and TA 100) and in the number of revertant (Trp+) colonies in the tester strain WP2uvrA both in the absence and presence of S9 -metabolic activation. These results were confirmed in an independently repeated experiment.

Based on the results of this study it is concluded that lithium hydroxide, respective lithium bromide is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay. (NOTOX, 2000)

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