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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: Comparable to guideline with acceptable restrictions: only 4 strains used, no cytotox. concentration given, no information on GLP

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Salmonella Mutagenicity tests: V. Results from the testing of 311 chemicals
Author:
Zeiger, E. et al.
Year:
1992
Bibliographic source:
Environm Mol Mutagen 19 [21], 2-141.
Reference Type:
secondary source
Title:
p-Toluidine - CAS No: 106-49-0 - SIDS Initial Assessment Report.
Author:
OECD
Year:
2005
Bibliographic source:
UNEP Publications

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
No GLP study. Only four strains were used. Number of replicated trials not reported
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
p-toluidine
EC Number:
203-403-1
EC Name:
p-toluidine
Cas Number:
106-49-0
Molecular formula:
C7H9N
IUPAC Name:
p-toluidine
Details on test material:
- Name of test material (as cited in study report): p-toluidine hydrochloride
- Analytical purity: 95.7%

Method

Target gene:
his
Species / strain
Species / strain / cell type:
other: Salmonella typhimurium TA97, TA98, TA100, TA1535
Metabolic activation:
with and without
Metabolic activation system:
S9-mix was prepared from Aroclor 1254-induced male Sprague-Dawley rats (RLI) and males Syrian Hamster (HLI) in 10 % and 30 % concentrations.
Test concentrations with justification for top dose:
0, 33, 100, 333, 1000, 2000, 3333 µg/plate in water
Vehicle / solvent:
- Vehicle/solvent used: water
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: see any other information on the material and methods
Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 min

DETERMINATION OF CYTOTOXICITY
- Method: All chemicals were run initially in a toxicity assay to determine the appropriate dose range for the mutagenicity assay. The toxicity assay was performed using TA100 or the system developed by Waleh et al. 1982. Mutat. Res. 97:247-256. Toxic concentrations were defined as those that produced a descrease in the number of his+ colonies, or a clearing in the density of the background lawn, or both.

Evaluation criteria:
A chemical was judged mutagenic or weakly mutagenic if it produced a reproducible dose-related response over the solvent control, under single metabolic activation condition, in replicate trials. A chemical was judged questionable (?) if the results of individual trials were not reproducible, if increases in his+ revertants did not meet the criteria for a "+W" response, or if only single doses produced increases in his+ revertants in repeat trials. Chemicals were judged nonmutagenic (-) if they did not meet the critearia for a mutagenic or questionable response.

Results and discussion

Test resultsopen allclose all
Species / strain:
other: Salmonella typhimurium TA97, TA98, TA1535
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
see remarks on results including tables and figures
Cytotoxicity / choice of top concentrations:
other: cytotoxicity was determined in preliminary experiments (no further information)
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
other: cytotoxicity was determined in preliminary experiments (no further information)
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 100
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: cytotoxicity was determined in preliminary experiments (no further information)
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Remarks on result:
other: other: Salmonella typhimurium TA97, TA98, TA100, TA1535
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1.Mutagenic responses (mean ± SEM; three plates) of Salmonella tester strains to p-toluidine HCl.

 

 

TA 100

TA 1535

DOSE

NA

(-)

NA

(-)

10% HLI

(?)

30% HLI

(+)

30% HLI

(+w)

10% RLI

(?)

30% RLI

(-)

NA

(-)

10% HLI

(-)

30% HLI

(-)

10% RLI

(-)

30% RLI

(-)

µg/PLATE

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

0

132

7.8

107

8.1

113

6.2

122

0.7

110

10.4

114

5.8

143

1.5

39

2.0

15

2.2

10

3.3

17

3.5

13

2.0

33

142

8.3

 

 

120

7.8

 

 

 

 

131

5.2

 

 

 

 

12

0.9

 

 

13

2.1

 

 

100

133

3.5

123

4.7

128

4.0

134

0.3

139

5.1

135

4.9

130

2.5

28

5.9

9

2.0

14

1.9

9

2.8

13

1.5

333

135

8.4

103

7.0

154

3.7

164

5.8

147

9.6

153

12.6

145

3.2

30

2.0

12

1.9

16

2.9

14

0.9

16

2.1

1000

137

5.1

122

6.0

146

4.4

219

23.4

158

9.5

157

3.3

155

14.2

32

2.3

16

2.5

18

1.9

13

2.2

15

1.8

2000

137s

6.2

116s

11.1

178s

8.2

239s

10.3

197s

19.0

157s

5.4

156s

9.3

33

5.4

15s

0.9

17

1.2

10s

2.5

17

2.3

3333

 

 

111s

7.3

 

 

256s

6.9

191s

10.7

 

 

156s

8.6

17s

3.5

 

 

17s

2.7

 

 

11s

1.5

POS

1441

49.7

1516

49.8

1622

18.3

993

9.9

1952

66.7

1577

21.7

525

16.3

1131

12.1

149

9.0

288

16.7

133

7.0

134

9.5

 

 

Table 2.Mutagenic responses (mean ± SEM; three plates) of Salmonella tester strains to p-toluidine HCl

 

 

 

 

TA97

TA98

DOSE

NA

(-)

10% HLI

(?)

30% HLI

(-)

10% RLI

(-)

30% RLI

(-)

NA

(-)

10% HLI

(-)

30% HLI

(-)

10% RLI

(-)

30% RLI

(-)

µg/PLATE

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

MEAN

SEM

0

138

4.3

110

6.6

194

12.8

135

4.2

233

6.4

17

3.5

30

3.9

29

2.2

39

2.2

40

1.7

33

 

 

140

12.2

 

 

157

4.3

 

 

 

 

37

3.9

 

 

40

1.7

 

 

100

131

0.3

172

3.0

205

8.7

146

10.2

227

17.2

15

1.5

35

4.1

28

1.5

43

3.5

34

2.6

333

127

7.2

148

1.5

212

12.7

151

6.3

220

14.6

16

5.7

36

1.2

40

1.7

44

1.2

36

4.7

1000

133s

3.5

135

8.3

200

5.8

173

5.0

193

3.9

19

2.6

38

5.0

44

7.7

38

2.8

47

5.2

2000

122s

2.0

144s

7.5

209s

8.9

166s

6.7

218s

8.8

15

0.9

38

1.5

45s

3.1

41

2.9

35

0.9

3333

99s

5.7

 

 

194s

2.6

 

 

184s

6.4

13s

1.2

 

 

46s

3.6

 

 

40s

4.4

POS

1257

33.7

1011

75.0

840

31.0

1087

30.4

477

11.8

1112

32.0

1930

44.6

1251

7.4

1571

43.9

443

22.0

 

HLI =Aroclor1254-induced hamster liver S9

RLI =Aroclor1254-induced rat liver S9;

s = slight clearing of background lawn (colonies not counted)

+ = mutagenic

+W= weakly mutagenic

? = questionable response;

- =non mutagenic

 

POS: positive control

 

 

 

 

Negative results were noted in all strains with and without metabolic activation except TA100 in the presence of hamster liver S9-mix.
The positive controls were functional.
Overall conclusion: weak positive

 

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
positive with metabolic activation in Salmonella typhimurium strain TA100
negative without metabolic activation in Salmonella typhimurium strain TA100
negative in Salmonella typhimurium strains TA97, 98 and 1535
Executive summary:

Zeiger (1992)

The Ames test was conducted with a method similar to OECD guideline 471 with deviations (only four strains were used. Positive controls were used, but the name of the substances were not mentioned)

p-toluidine in concentrations ranging between 0 and 3333 µg/plate using Salmonella typhimurium TA97, TA98 and TA1535 without metabolic activation and in the presence of hamster or rat liver S9-mix was found not mutagenic. Salmonella typhimurium TA100 was tested negative without metabolic activation and in the presence of rat liver S9-mix but was positive in the presence of hamster liver S9-mix. Concurrent positive controls were always functional.