3-(methylthio)propionaldehyde

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted July 21, 1997

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

3-(methylthio)propionaldehyde

EC Number:

221-882-5

EC Name:

3-(methylthio)propionaldehyde

Cas Number:

3268-49-3

Molecular formula:

C4H8OS

IUPAC Name:

3-(methylthio)propionaldehyde

Test material form:

liquid

Method

Target gene:

The Salmonella typhimurium histidine (his) and the Escherichia coli tryptophan (trp) reversion system measures his-→ his+ and trp-→ trp+ reversions, respectively.

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Cofactor supplemented post-mitochondrial fraction (S9 mix), prepared from the livers of rats treated with phenobarbital/ß-naphtoflavone.

Test concentrations with justification for top dose:

In a pre-experiment a concentration range of the test item was 3 – 5000 μg/plate. The pre-experiment is reported as experiment I. Since toxic effects were observed in experiment I, eight concentrations were tested in experiment II. 5000 μg/plate were chosen as maximal concentration. The concentration range included two logarithmic decades. The following concentrations were tested in experiment II: 3; 10; 33; 100; 333; 1000; 2500; and 5000 μg/plate.

Experiment 1 (plate incorporation test) and Experiment 2 (preincubation test): 3, 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate, with and without metabolic activation

Vehicle / solvent:

- Vehicle/solvent used: DMSO
- Justification for choice of solvent/vehicle: The solvent has been chosen according to its solubility properties and its relative nontoxicity to the bacteria.

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

methylmethanesulfonate

other: 2-aminoanthracene dissolved in DMSO; for TA 1535, TA 1537, TA 98, TA 100, WP2 uvrA; +S9 // 4-nitro-o-phenylene-diamine, 4-NOPD dissolved in DMSO; for TA 1537, TA 98; -S9

Details on test system and experimental conditions:

NUMBER OF REPLICATIONS:
- Number of cultures per concentration: triplicate

METHOD OF TREATMENT/ EXPOSURE:
- Test substance added in agar (plate incorporation); preincubation

TREATMENT AND HARVEST SCHEDULE:
- Preincubation period: 60 min
- Exposure duration/duration of treatment: 48 hours at 37 C ± 1.5° C in the dark

METHODS FOR MEASUREMENT OF CYTOTOXICITY
- Method: background growth inhibition

METHODS FOR MEASUREMENTS OF GENOTOXICIY
- Method: Number of revertant colonies

Evaluation criteria:

A test item is considered as a mutagen if a biologically relevant increase in the number of revertants of twofold or above (strains TA 98, TA 100, and WP2 uvrA) or threefold or above (strains TA 1535 and TA 1537) the spontaneous mutation rate of the corresponding solvent control is observed. A dose dependent increase is considered biologically relevant if the threshold is reached or exceeded at more than one concentration. An increase of revertant colonies equal or above the threshold at only one concentration is judged as biologically relevant if reproduced in an independent second experiment. A dose dependent increase in the number of revertant colonies below the threshold is regarded as an indication of a mutagenic potential if reproduced in an independent second experiment. However, whenever the colony counts remain within the historical range of negative and solvent controls such an increase is not considered biologically relevant.

Statistics:

Mean values and standard deviation were calculated.

Results and discussion

Test results

Key result

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

in all strains at higher concentrations with and without metabolic activation

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation and time of the determination: No precipitation of the test item occurred in the overlay agar in the test tubes. Precipitation of the test item in the overlay agar on the incubated agar plates was observed at 5000 μg/plate.

STUDY RESULTS
- Concurrent vehicle negative and positive control data

Ames test:
- Signs of toxicity , Individual plate counts , Mean number of revertant colonies per plate and standard deviation : Refer to Table no. 1 and 2 under "Any other information on results incl. tables".

HISTORICAL CONTROL DATA
- Positive historical control data: yes
- Negative (solvent/vehicle) historical control data: yes

Any other information on results incl. tables

Table 1:

Summary of Experiment I
Metabolic Activation	Test Group	Dose level per plate	Revertant Colony Count (Mean)
			TA1535	TA1537	TA98	TA100	WP2uvRA
without activation	DMSO		20	10	24	138	39
	Untreated		18	13	28	146	43
	MMP	3 µg	16	8	25	127	40
		10 µg	19	11	20	139	40
		33 µg	17	10	30	129	41
		100 µg	19	9	28	121	41
		333 µg	21	9	33	121	39
		1000 µg	23	12	21	138	54
		2500 µg	8	6	10	1	41
		5000 µg	1P	1P	1P	0P	2P
	NaN3	10 µg	1612			2374
	4-NOPD	10 µg			378
	4-NOPD	50 µg		79
	MMS	2.0 µL					1085
with activation	DMSO		15	11	37	127	49
	Untreated		19	16	34	128	56
	MMP	3 µg	16	15	36	127	47
		10 µg	19	10	39	126	47
		33 µg	15	11	37	134	48
		100 µg	19	10	41	126	55
		333 µg	19	13	38	107	52
		1000 µg	20	13	29	99	48
		2500 µg	20	8	23	96	52
		5000 µg	2P	3P	1P	1P	34P
	2-AA	2.5 µg	362	369	3793	4827
	2-AA	10.0 µg					222

P: Precipitate, NaN3: sodium azide, 2 -AA: 2- aminoanthracene, 4 -NOPD: 4 -nitro-o-phenylene-diamine, MMS: methyl methane sulfonate

Table 2:

Summary of Experiment II
Metabolic Activation	Test Group	Dose level per plate	Revertant Colony Count (Mean)
			TA1535	TA1537	TA98	TA100	WP2uvRA
without activation	DMSO		10	8	24	93	41
	Untreated		14	16	21	105	41
	MMP	3 µg	10	7	18	93	38
		10 µg	8	9	23	100	39
		33 µg	12	10	27	98	35
		100 µg	13	10	27	105	42
		333 µg	14	8	30	120	44
		1000 µg	13	4	16	116	51
		2500 µg	3	1	7	2	6
		5000 µg	0P	0P	5	0P	0P
	NaN3	10 µg	1302			2050
	4-NOPD	10 µg			538
	4-NOPD	50 µg		119
	MMS	2.0 µL					736
with activation	DMSO		13	13	30	94	45
	Untreated		12	15	40	90	48
	MMP	3 µg	17	17	32	95	49
		10 µg	14	11	30	101	44
		33 µg	13	13	27	94	54
		100 µg	15	12	32	103	53
		333 µg	12	12	29	93	41
		1000 µg	15	14	35	90	43
		2500 µg	9	11	3	6	46
		5000 µg	0P	0P	0P	0P	0P
	2-AA	2.5 µg	305	349	3950	2831
	2-AA	10.0 µg					225

P: Precipitate, NaN3: sodium azide, 2 -AA: 2- aminoanthracene, 4 -NOPD: 4 -nitro-o-phenylene-diamine, MMS: methyl methane sulfonate

Applicant's summary and conclusion

Conclusions:

Interpretation of results: negative with and without metabolic activation, no mutagenic potential was detected in the bacterial reverse mutation assay.