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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:
from 02-02-1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was conducted according to the appropriate EU test guideline, and in compliance with GLP and is therefore considered to be reliability 1. Read-across of the study itself is considered to be reliability 2. Further information on read-across is given in the endpoint summary.
Justification for type of information:
Please refer to the attached justification below and the overall justification for grouping of substances attached in IUCLID Section 13.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report Date:
1995

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
His operon (S. typhimurium strains)
Trp operon (E. coli strains)
Species / strain
Species / strain / cell type:
other: Salmonella typhimurium TA 98, TA 100, TA 1535, TA 1537; Escherichia coli WP2 and WP2 uvrA
Metabolic activation:
with and without
Metabolic activation system:
cofactor supplemented post-mitochondrial fraction (S9 mix), prepared from the livers of rats treated with Aroclor 1254.
Test concentrations with justification for top dose:
100, 333, 1000, 3333, and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: the solvent was chosen based on solubility of the test article and compatibility with the target cells.
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
2-nitrofluorene
Remarks:
TA 98 (without metabolic activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
TA 100, TA 1535 (without metabolic activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
TA 1537 (without metabolic activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
WP2, WP2uvrA (without metabolic activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene
Remarks:
All strains (with metabolic activation)
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Sterigmatocystin
Remarks:
All strains (with metabolic activation)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION

- Preincubation period: 60 minutes
- Expression time (cells in growth medium): 48 to 72 hours

NUMBER OF REPLICATIONS: 2 plates per test concentration

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth; background lawn assessment
Evaluation criteria:
The test article is evaluated as positive when it causes a dose-related increase in mean revertants per plate of at least one tester strain with a minimum of two increasing concentrations of test article.
Statistics:
Positive controls and tester strains with revertant counts greater than 100 were counted with a colony counter (Mini Count) and those less than 100 were counted manually.

Results and discussion

Test results
Species / strain:
other: Salmonella typhimurium TA 98, TA 100, TA 1535, TA 1537; Escherichia coli WP2 and WP2 uvrA
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Remarks:
> 5000 µg/plate
Vehicle controls validity:
not specified
Untreated negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: none recorded
- Effects of osmolality: none recorded
- Evaporation from medium: not reported
- Precipitation: Slight precipitation at higher concentrations did not affect assay
- Other confounding effect: In first two tests, a variation in the precipitation pattern was observed, so the tests were repeated. The findings from the initial two experiments are not recorded.

RANGE-FINDING/SCREENING STUDIES:
No toxicity observed

COMPARISON WITH HISTORICAL CONTROL DATA:
The results of the controls lie within the range of the historical control data.


Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

 

Table 1 Preliminary toxicity test

 

TA 100

WP2 uvrA (pKM101)

Concentration (μg/Plate)

Plate 1

+ MA

Plate 2

- MA

Cytotoxic (Yes/No)

Plate 1

+ MA

Plate 2

- MA

Cytotoxic (Yes/No)

0

199

174

no

250

208

no

6.7

180

173

no

234

187

no

10

165

157

no

241

210

no

33

174

163

no

200

198

no

67

179

197

no

228

185

no

100

196

152

no

195

217

no

333

177

170

no

186

184

no

667

175

175

no SP

230

214

no SP

1000

169

156

no SP

138

168

no SP

3333

199

174

no SP

221

169

no SP

5000

174

158

no SP

247

180

no SP

SP Slight precipitate

 

Table 2: Experiment 1 Plate incorporation assayNumber of revertants per plate (mean of 3 plates)

 

TA98

TA100

TA1535

Conc.
(
µg/plate)

-MA

+ MA

Cytotoxic
(yes/no)

-

 MA

+ MA

Cytotoxic
(yes/no)

-

MA

+ MA

Cytotoxic
(yes/no)

0*

13

17

no

95

144

no

10

11

no

100

13

17

no

89

127

no

9

11

no

333

13

18

no

86

135

no

8

11

no

1000

14

16

no

85

116

no

9

11

no

3333

17

21

no

97

116

no

6

14

no

5000

13

21

no

95

111

no

7

13

no

Positive Control

1304

1050

-

581

997

-

497

124

-

*solvent control with DMSO

 

Table 2: Experiment 1 Plate incorporation assayNumber of revertants per plate (mean of 3 plates)

 

TA1537

WP2 uvrA (pKM101)

WP2 (pKM101)

Conc.
(
µg/plate)

-MA

+ MA

Cytotoxic
(yes/no)

-

 MA

+ MA

Cytotoxic
(yes/no)

-

MA

+ MA

Cytotoxic
(yes/no)

0*

4

6

no

226

263

no

65

64

no

100

4

10

no

236

295

no

54

64

no

333

3

5

no

239

258

no

87

60

no

1000

6

8

no

210

294

no

62

53

no

3333

5

8

no

213

273

no

67

64

no

5000

5

6

no

197

247

no

67

61

no

Positive Control

215

130

-

1554

1262

-

1476

499

-

 

 

*solvent control withDMSO

 

Table 3: Experiment 2 Pre incubation assayNumber of revertants per plate (mean of 3 plates)

 

TA98

TA100

TA1535

Conc.
(
µg/plate)

— MA

+ MA

Cytotoxic
(yes/no)

 MA

+ MA

Cytotoxic
(yes/no)

MA

+ MA

Cytotoxic
(yes/no)

0*

15

24

no

102

129

no

11

10

no

50

26

24

no

112

122

no

10

11

no

160

21

20

no

105

116

no

11

9

no

500

24

14

no

101

120

no

12

10

no

1600

23

17

no

110

128

no

9

12

no

5000

19

18

no

100

123

no

10

11

no

Positive Control

764

909

-

527

902

-

433

117

-

*solvent control with DMSO

 

Table 3: Experiment 2 Pre incubation assayNumber of revertants per plate (mean of 3 plates)

 

TA1537

WP2 uvrA (pKM101)

WP2 (pKM101)

Conc.
(
µg/plate)

-MA

+ MA

Cytotoxic
(yes/no)

-

 MA

+ MA

Cytotoxic
(yes/no)

-

MA

+ MA

Cytotoxic
(yes/no)

0*

5

7

no

204

334

no

23

21

no

100

5

5

no

274

278

no

25

21

no

333

5

5

no

173

316

no

26

25

no

1000

5

6

no

208

296

no

26

22

no

3333

5

4

no

206

285

no

31

28

no

5000

5

6

no

214

283

no

28

24

no

Positive Control

250

119

-

2225

1304

-

358

1222

-

 

*solvent control withDMSO

 

Applicant's summary and conclusion

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

In a bacterial reverse mutation assay according to OECD 471 and GLP, the structural analogue substance trimethoxysilane (CAS:2487-90-3) was concluded to be negative in the Salmonella typhimurium/E. coli preincubation mutagenicity assay with a confirmatory assay. The test substance is non-mutagenic in strains used for this study.