Trichloro(methyl)silane

Genetic toxicity: in vitro

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

Study period:

1977-12-08 to 1977-12-11

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to a test protocol that is comparable to the appropriate OECD test guideline. It was not compliant with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1978

Report date:

1978

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

range of strains and no replicates

Principles of method if other than guideline:

Method: other: Litton Bionetics standard procedure: Screening Program for the Identification of Potential Mutagens and Carcinogens. Protocol Number : DMT 100

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Trichloro(methyl)silane

EC Number:

200-902-6

EC Name:

Trichloro(methyl)silane

Cas Number:

75-79-6

Molecular formula:

CH3Cl3Si

IUPAC Name:

trichloro(methyl)silane

Method

Species / strain

Species / strain / cell type:

other: Salmonella typhimurium: TA 1535, TA 1537, TA 1538, TA 98 and TA100; Saccharomyces cerevisiae D4, and E coli Pol A+/A-

Metabolic activation:

with and without

Metabolic activation system:

Aroclor induced rat liver S9

Test concentrations with justification for top dose:

0.001-5 µl/plate, equivalent to approx 10-5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: ethanol

- Justification for choice of solvent/vehicle: no information

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Methylnitrosoguanidine

Remarks:

TA 1535, TA 100, D4 (without activation)

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Quinicrine Mustard

Remarks:

TA 1537 (without activation)

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

TA 1535, TA 98 (without activation)

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-anthramine

Remarks:

TA 1535, TA 100, D4 (with activation)

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 8-aminoquinoline

Remarks:

TA 1537 (with activation)

Controls 6

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-acetylaminofluorene

Remarks:

TA 1538, TA 98 (with activation)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION

- Expression time (cells in growth medium): 48 hours

NUMBER OF REPLICATIONS: 2 plates for each test concentration for strains TA 98 and TA 1537

DETERMINATION OF CYTOTOXICITY

- Method: relative total growth; background lawn

Statistics:

Responses (number of revertants) from the test substance were compared to concurrent negative and positive controls, as well as to historical data.

Results and discussion

Test results

Species / strain:

other: Salmonella typhimurium: TA 1535, TA 1537, TA 1538, TA 98 and TA100; Saccharomyces cerevisiae D4, and E coli Pol A+/A-

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: at 5 µg/plate with TA 1535, TA 1537 and TA 1538 and D4 ; and 1 and 5 ug/plate for E.coli

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

The results of the tests conducted without metabolic activation were all negative. The test with the TA 1535 and TA 1537 strains were repeated due to increased numbers of revertants being observed - these results are not presented in detail in the study report. The repeat tests were negative. The E. coli tests were also repeated to determine if the zone of inhibition was due to an effect on the DNA. The repeat test showed that the inhibition was due to the toxicity of the chemical.

With activation, the test substance exhibited toxicity with strains TA 1535, TA 1537, TA 1538 and D4 at 5 µg/plate. There was also toxicity to the E. coli strains at 1 and 5 µl /plate.

For the Salmonella strains, revertants per plate for the positive control substances ranged from 124 to >1000, depending on the agent and strain.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

 

Table 2 : Experiment 1 Plate incorporation number of revertants per plate

	TA 98			TA 100			TA 1535
Conc. (µl/ml)	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)
0*	63	49	No	230	217	No	30	29	No
0.001	89	43	No	260	136	No	38	33	No
0.01	87	69	No	220	158	No	28	27	No
0.1	75	77	No	227	148	No	21	30	No
1	74	74	No	203	187	No	15	33	Yes
5	47	19	Yes	106	159	Yes	0	10	Yes
Positive control	636	870	No	672	921	No	681	240	No

*solvent control withEthanol

 

Table 2: Experiment 1 Plate incorporation number of revertants per plate

	TA 1537			TA 1538
Conc. (µl/ml)	— MA	+ MA	Cytotoxic (yes/no)	— MA	+ MA	Cytotoxic (yes/no)
0*	9	16	No	13	20	No
0.001	19	18	No	20	20	No
0.01	6	17	No	19	12	No
0.1	12	16	No	24	12	No
1	3	22	Yes	31	11	No
5	4	11	Yes	4	11	Yes
Positive control	724	210	No	593	635	No

*solvent control withEthanol

Applicant's summary and conclusion

Conclusions:

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

Trimethylchlorosilane has been tested for mutagenicity to bacteria in a valid assay using a protocol that is similar to OECD 471. Appropriate concurrent negative and positive controls were included, and the expected responses were observed. The test substance, trimethylchlorosilane (CAS No. 75-79-6), exhibited some toxicity to 3 of the Salmonella strains. However there was no reproducible evidence of mutagenic activity in any of the assays conducted, both with and without metabolic activation. In addition, no genotoxic activity was observed in Saccharomyces cerevisiae D4, nor in the E coli Pol A+/A- zone of inhibition assay. The test substance was not considered to be mutagenic under these test conditions.