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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:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Justification for type of information:
Data is from peer reviewed publication

Data source

Reference
Reference Type:
publication
Title:
Gene mutation toxicity study of the test chemical
Author:
Mortelmans et al
Year:
1986
Bibliographic source:
Environ. Mutagen

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: Similar to OECD 471
Principles of method if other than guideline:
The test chemical was examined for its ability to induce mutagenic changes when tested in Salmonella typhimurium bacterial strains in the presence and absence of metabolic activation with rat and hamster S-9 mix using the preincubation assay method.
GLP compliance:
no
Type of assay:
bacterial gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material: Benzyl acetate
- Molecular formula: C9H10O2
- Molecular weight: 150.176 g/mol
- Substance type:Organic
- Physical state:Liquid

Method

Target gene:
Histidine
Species / strain
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 specified
Cytokinesis block (if used):
No data
Metabolic activation:
with and without
Metabolic activation system:
Sp metabolic activation system isolated from Aroclor 1254-induced males Sprague Dawley rat and Syrian hamsters
Test concentrations with justification for top dose:
0, 33, 100, 333, 1000, 3333 or 10000 ug/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: The chemical was soluble in DMSO
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
9-aminoacridine
sodium azide
other: 4-nitro-o-phenylenediamine, 2-aminoanthracene
Details on test system and experimental conditions:
METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 minutes
- Exposure duration: 48 hours
- Expression time (cells in growth medium): 48 hrs
- Selection time (if incubation with a selection agent): No data available
- Fixation time (start of exposure up to fixation or harvest of cells): No data available

SELECTION AGENT (mutation assays): No data available
SPINDLE INHIBITOR (cytogenetic assays): No data available
STAIN (for cytogenetic assays): :No data available

NUMBER OF REPLICATIONS: : All assays were repeated in duplicate one week after completion of the initial test. At least five dose levels of the chemicals were tested, with three plates per dose level.

NUMBER OF CELLS EVALUATED: :No data available

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; cloning efficiency; relative total growth; No data available

OTHER EXAMINATIONS:
- Determination of polyploidy: No data available
- Determination of endoreplication: No data available
- Other: No data available

OTHER: At least one toxic dose was incorporated into the first mutagenicity test, the repeat test(s) occasionally had the doses adjusted so that an apparent toxic dose was not reached.
Rationale for test conditions:
No data
Evaluation criteria:
1) mutagenic response: a dose-related, reproducible increase in the number of revertants over background, even if the increase was less than twofold;
2) nomutagenic response: when no increase in the number of revertants was elicited by the chemical;
3) questionable response: when there was an absence of a clear-cut dose-related increase in revertants; when the dose-related increases in the number of revertants were not reproducible; or when the response was of insufficient magnitude to support a determination of mutagenicity.
Statistics:
No information available.

Results and discussion

Test results
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:
not specified
Vehicle controls validity:
valid
Untreated negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: No data
- Effects of osmolality: No data
- Evaporation from medium: No data
- Water solubility: No data
- Precipitation: No data
- Other confounding effects: No data

RANGE-FINDING/SCREENING STUDIES: The chemical was tested initially with strain TA100 in the presence and the absence of the metabolic activation systems, over a wide dose range with an upper limit of 10 mgjplate, or less when solubility problems were encountered. Toxicity was evidenced by one or more of the following phenomena: appearance of his+ pinpoint colonies, reduced numbers of revertant colonies per plate, or thinning or absence of the bacterial lawn. Nontoxic chemicals were tested in the initial experiment up to the 10 mg/plate dose level, or to a level determined by their solubility. Toxic chemicals were tested up to a high dose which exhibited some degree of toxicity.

COMPARISON WITH HISTORICAL CONTROL DATA: No data

ADDITIONAL INFORMATION ON CYTOTOXICITY: No data
Remarks on result:
other: No mutagenic potential

Any other information on results incl. tables

Table: Mutation data for the test chemical

Dose (µg/plate)

TA100

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

97

5.5

102

7.3

105

14.9

33

102

4.7

 

 

 

 

100

101

4.0

67

2.7

122

2.9

333

85

5.8

97

9.6

118

12.3

1000

91

14.4

93

2.7

99

12.1

3333

58

11.7

104

15.5

78

4.1

10000

 

 

84

9.0

95

6.5

Positive control

481

29.2

1770

34.1

961

89.2

 

Dose (µg/plate)

TA1535

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

8

0.3

7

1.5

6

1.3

33

5

0.9

 

 

 

 

100

4

0.6

6

1.2

6

1.5

333

5

0.6

8

1.2

6

1.2

1000

4

0.6

2

0.9

3

0.3

3333

3

0.3

3

1.2

8

3.0

10000

 

 

1

0.7

5

2.3

Positive control

724

63.9

106

2.6

43

3.5

 

Dose (µg/plate)

TA1537

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

2

0.0

6

1.2

7

1.3

33

 

 

 

 

 

 

100

2

1.0

8

2.3

6

1.2

333

5

1.3

4

0.9

9

0.3

1000

1

0.7

4

1.2

7

3.2

3333

5

 

3

0.3

5

1.5

10000

T

 

6

1.2

9

1.3

Positive control

224

32.4

79

9.2

82

14.2

 

Dose (µg/plate)

TA98

NA

10% HLI

10% RLI

Mean

SEM

Mean

SEM

Mean

SEM

0

12

2.8

16

2.6

20

1.2

33

 

 

 

 

 

 

100

11

1.2

20

1.8

23

2.5

333

13

0.3

20

3.8

24

1.9

1000

15

3.5

16

1.9

20

3.2

3333

12

2.3

19

2.3

19

4.8

8

1.0

12

1.3

18

4.1

 

Positive control

140

3.7

1169

69.6

324

49.4

 

T: Complete clearing of background lawn

 

Applicant's summary and conclusion

Conclusions:
The test chemical did not induce mutation in the Salmonella typhimurium strain TA98, TA100, TA1535 or TA1537 both in the presence and absence of S9 metabolic actuvation system and hence does not classify for gene mutation under the conditions of this study.
Executive summary:

The test chemical was examined for its ability to cause mutagenic changes when tested in five strains of the bacteria Salmonella typhimurium, specifically, TA 1535, TA 1537, TA97, TA 98 and TA 100 through the preincubation assay method. Preliminary dose range finding study was performed initially to set the doses for the main study. The test was conducted both in the presence and absence of metabolic activation using male rat and hamster liver derived S-9 mix at dose levels of 0, 33, 100, 333, 1000, 3333 or 10000 ug/plate. The test was repeated and atleast three plates were used at each dose level. The test chemical did not induce mutation in the Salmonella typhimurium strain TA98, TA100, TA1535 or TA1537 both in the presence and absence of S9 metabolic activation system and hence does not classify for gene mutation under the conditions of this study.