S-(3-(triethoxysilyl)propyl)octanethioate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 Apr - 17 May 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

certified by Hessisches Ministerium für Umwelt, Energie, Jugend, Familie und Gesundheit, 1998

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Details on test material:

- Name of test material (as cited in study report): Y-15099
- Physical state: pale yellow liquid
- Analytical purity: 97.8%
- Lot/batch No.: 18244-30
- Expiration date of the lot/batch: 2002-10-23
- Stability under test conditions: stable in ethanol
- Storage condition of test material: room temperature

Method

Target gene:

his operon (S. typhimurium)
trp operon (WP2 uvrA)

Species / strain

Species / strain / cell type:

other: S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and WP2 uvrA

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

0, 33, 100, 333, 1000, 2500 and 5000 µg/plate

Vehicle / solvent:

Ethanol

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Remarks:

sodium azide (+S9: 10 µg/plate in TA 1535, TA 100), 4-nitro-o-phenylene-diamine (+S9: 10 µg/plate in TA 98, 50 µg/plate in TA 1537), methylmethanesulfonate (+S9: 5 µL/plate in WP2 uvrA), 2-aminoanthracene (-S9: 2.5 µg/plate and 10 µg/

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation) (Experiment 1) and pre-incubation test (Experiment 2)

DURATION
- Preincubation period: 60 minutes
- Exposure duration: 48 hours

NUMBER OF REPLICATIONS: triplicates in 2 independent experiments

DETERMINATION OF CYTOTOXICITY
- Method: background growth and reduction in the number of revertants

Evaluation criteria:

A test item is considered positive if either a dose related increase in the number of revertants or a biologically relevant increase for at least one test concentration is induced.
A test item producing neither a dose related increase in the number of revertants, nor a biologically relevant positive response at any one of the test points is considered non-mutagenic in this system.
A mutagenic response is described as follows:
A test item is considered mutagenic if in the strains Ta 98, TA 100, and WP2 uvrA the number of reversions will be at least twice as high and in the strains TA 1535 and TA 1537 at least three times higher as compared to the spontaneous reversion rate.
Also, a dose-dependent increase in the number of revertants is regarded as an indication of possibly existing mutagenic potential of the test regardless whether the highest dose induced the above described enhancement factors or not.

Statistics:

No data.

Results and discussion

Test results

Species / strain:

other: S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and WP2 uvrA

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 100 and 1000 - 5000 µg/plate in TA 100 -S9; 1000 - 5000 µg/plate in TA 1535, TA 1537, TA 98, and TA 100 with S9; 2500 - 5000 µg/plate in WP2 uvrA with S9

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

ADDITIONAL INFORMATION ON CYTOTOXICITY:
The plates incubated with the test item showed normal background growth up to 5000 µg/plate with and without S9 mix in both experiments.
Toxic effects, evident as a reduction in number of revertants, were observed in all strains at concentrations of 1000 µg/plate or above. Additionally toxic effects were seen in strain TA 100 at 100 µg/plate without S9 mix.

Any other information on results incl. tables

Table 1: Ames Test Results - Experiment 1 (Plate incorporation Test)

With or without S9-Mix	Test substance concentration (µg/plate)	Mean number of revertant colonies per plate (average of triplicate)
		Base-pair substitution type			Frameshift type	Base-pair substitution and other
		TA 1535	TA1537	TA 100	TA98	WP2 uvrA
-	Negative control	11	9	164	31	52
-	Vehicle control	14	10	136	30	51
-	33	11	11	161	35	52
-	100	14	13	153	35	58
-	333	17	12	156	40	53
-	1000	18	11	159	35	62
-	2500	15	12	144	40	58
-	5000	14	16	144	36	58
Positive controls - S9	Name	SA	4NP	SA	4NP	MMS
	Concentrations (µg/plate)	10	50	10	10	5 µl
	Number of colonies/plate	1549	58	625	159	856
		TA 1535	TA 1537	TA 100	TA98	WP2 uvrA
+	Negative control	17	20	185	40	50
+	Vehicle control	16	14	184	49	52
+	33	21	22	173	40	56
+	100	23	20	145	41	63
+	333	18	17	151	45	60
+	1000	22	22	135	44	52
+	2500	18	26	148	40	60
+	5000	11	13	114	27	40
Positive controls + S9	Name	2AA	2AA	2AA	2AA	2AA
	Concentrations (µg/plate)	2.5	2.5	2.5	2.5	10
	Number of colonies/plate	263	130	912	477	226

Table 2: Ames Test Results - Experiment 2 (Pre-Incubation Test)

With or without S9-Mix	Test substance concentration (µg/plate)	Mean number of revertant colonies per plate (average of triplicate)
		Base-pair substitution type			Frameshift type	Base-pair substitution and other
		TA 1535	TA1537	TA 100	TA98	WP2 uvrA
-	Negative control	14	6	147	21	42
-	Vehicle control	9	8	133	27	41
-	33	14	8	88	31	42
-	100	10	6	69	23	45
-	333	8	7	87	20	47
-	1000	8	4	63	25	45
-	2500	7	5	67	31	37
-	5000	7	6	72	28	67
Positive controls - S9	Name	SA	4NP	SA	4NP	MMS
	Concentrations (µg/plate)	10	50	10	10	5 µl
	Number of colonies/plate	618	53	759	189	414
		TA 1535	TA 1537	TA 100	TA98	WP2 uvrA
+	Negative control	20	12	168	28	51
+	Vehicle control	23	9	150	36	48
+	33	14	12	131	35	71
+	100	14	5	143	33	68
+	333	16	6	90	26	64
+	1000	5	3	59	10	30
+	2500	8	1	4	6	19
+	5000	6	0	0	0	19
Positive controls + S9	Name	2AA	2AA	2AA	2AA	2AA
	Concentrations (µg/plate)	2.5	2.5	2.5	2.5	10
	Number of colonies/plate	151	63	681	387	218

SA = Sodium azide

4NP = 4-Nitro-o-phenylene-diamine

MMS = Methyl methane sulfonate

2AA = 2-Aminoanthracene

Applicant's summary and conclusion

Conclusions:

During the mutagenicity test and under the experimental conditions reported, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used.

Executive summary:

This study was performed to investigate the potential of Y-15099 to induce gene mutations according to the OECD guideline 471 in a plate incorporation test (Experiment 1) and a pre-incubation test (Experiment 2) using Salmonella typhimurium strains TA 1535, TA 1537, TA 98, and TA 100, and the Escherichia coli strain WP2 uvrA.

The assay was performed in 2 independent experiments both with and without liver microsomal activation. Each concentration, including the controls, was tested in triplicate. The test item was tested at the following concentrations: 0, 33, 100, 333, 1000, 2500, and 5000 µg/plate.

The plates incubated with the test item showed normal background growth up to 5000 µg/plate with and without metabolic activation. Toxic effects, evident as a reduction in number of revertants, were observed in all strains at concentrations of 1000 µg/plate or above. Additionally toxic effects were seen in strain TA 100 at 100 µg/plate without S9 mix.

No substantial increase in revertant colony numbers of any of the 5 tester strains was observed following treatment with Y-15099 at any dose level, neither in the presence nor absence of metabolic activation (S9 mix). There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance.

Appropriate reference mutagens were used as positive controls and showed a distinct increase of induced revertant colonies.