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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study is comparable to OECD Guideline 471 with acceptable restrictions (not tested in E. coli WP2 uvrA or S. typhimurium TA102; no cytotoxic effects at the high dose level and not tested up to 5 mg/plate; no positive control in TA1538 without metabolic activation)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979
Report Date:
1979

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Principles of method if other than guideline:
according to Ames, B.N. et al.: Mutation Research 31, 347-364
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Purity > 97.5%
No further details

Method

Target gene:
His-
Species / strain
Species / strain / cell type:
other: Salmonella typhimurium TA 1535, TA 1537, TA 1538, TA 98, TA 100
Metabolic activation:
with and without
Metabolic activation system:
(MA) rat liver S9-mix; 5 male Sprague-Dawley rats i.p. injected with 500 mg/kg bw Aroclor1254, rats sacrificed at day 5 and liver S9-fraction prepared. Addition of co-factors (use of S9-mix).
Test concentrations with justification for top dose:
0, 4, 20, 100, 500, 2500 µg/plate
Vehicle / solvent:
distilled water
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
other: without MA 5 µg/plate methyl-N'-nitro-N-nitroso-guanidine for all strains except TA1538, with MA: 10 µg/plate 2-aminoanthracene for all strains and additionally 500 µg/plate cyclophosphamide in TA100 & TA1535
Details on test system and experimental conditions:
METHOD OF APPLICATION: plate incorporation method
DURATION
- Preincubation period: no
- Exposure duration: 48 h
NUMBER OF REPLICATIONS: 4 plates per dose level

DETERMINATION OF CYTOTOXICITY
- Method: not specified by the authors; presumably reduction in revertants and effects on bacterial lawn
Evaluation criteria:
- at least doubling of the number of revertants
- Dose-related effects
- Reproducibility of results
Statistics:
no data

Results and discussion

Test results
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:
Results are tabulated for each plate (n=4 per dose level per strain). Mean +/- standard deviation is given in the Table below. No increase in revertants at any dose level in any strain studied.
The positive controls resulted in the expected increase of revertants compared to concurrent vehicle controls (no positive control in TA1538 without MA). No decrease in the number of revertants at the high dose level indicating no cytotoxicity. Authors comment: no cytotoxic effects at the high dose level. However, evaluation of cytotoxicity was not mentioned (presumably effects on bacterial lawn). Historical control data were not given, but the documented concurrent control values are within the usual range.
Remarks on result:
other:
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Mutagenic effects in the Ames test

Mean revertants +/- standard deviation calculated from the original reference data
4 plates per dose per strain

Dose in µg/plate

TA98

TA100

TA1535

TA1537

TA1538

Without metabolic activation

0

36+/-4      

135+/-19

13+/-1      

6+/-1

13+/-1

4

35+/-6  

138+/-17 

14+/-3

8+/-2

14+/-2

20

34+/-3     

134+/-14

14+/-2      

7+/-2      

15+/-2

100

34+/-7     

149+/-19

13+/-3      

7+/-3      

13+/-2

500

34+/-3   

139+/-3

13+/-3

8+/-3      

11+/-2

2500

34+/-4      

148+/-24

14+/-2      

7+/-1      

12+/-1 

Positive control

1650+/-122 

3400+/-245

2925+/-225 

48+/-6        

No data

Dose in µg/plate

TA98

TA100

TA1535

TA1537

TA1538

With metabolic activation

0

35+/-2

129+/-12

20+/-2

10+/-3      

23+/-3

4

34+/-3     

141+/-12

18+/-1     

11+/-1      

22+/-3

20

32+/-4     

148+/-17

17+/-2     

12+/-2      

20+/-3

100

32+/-4     

137+/-13

18+/-3     

13+/-5      

22+/-5

500

34+/-2     

144+/-16

19+/-2     

11+/-2      

21+/-3

2500

32+/-4      

138+/-5

18+/-3     

10+/-2      

20+/-3

Positive control

1812+/-63   

3025+/-222

183+/-24   

153+/-34   

1002+/-149



Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

No mutagenic and no cytotoxic effects in TA98, TA100, TA1535, TA1537, TA1538 with and without metabolic activation at dose levels up to 2500 µg/plate.
Executive summary:

The study is comparable to OECD Guideline 471 with acceptable restrictions (not tested in E. coli WP2 uvrA or S. typhimurium TA102; no cytotoxic effects at the high dose level and not tested up to 5 mg/plate; no positive control in TA1538 without metabolic activation)

Salmonella typhimurium TA 1535, TA 1537, TA 1538, TA 98, TA 100 were exposed with and without metabolic activation to dose levels of 0 (vehicle control), 4, 20, 100, 500, 2500 µg/plate. The positive and negative controls were valid. No cytotoxic effects were detected at these dose levels. No increase in revertants was found at any dose level in any strain studied.

Conclusion: No mutagenic and no cytotoxic effects with and without metabolic activation at dose levels up to 2500 µg/plate.