(2-hydroxyethyl)ammonium mercaptoacetate

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Data source

Reference

Reference Type:

publication

Title:

Salmonella mutagenicity tests: III. Results from the testing of 255 chemicals

Author:

Zeiger E, Anderson B, Haworth S, Lawlor T, Mortelmans K and Speck W

Year:

1987

Bibliographic source:

Environ Mutagen, 9(suppl.9), 1-109

Materials and methods

Test guideline

Qualifier:

equivalent or similar to

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

not specified

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Reference

Name:

Unnamed

Type:

Constituent

Details on test material:

Test compound: sodium thioglycolate
CAS no.: 367-51-1
Source: Matheson Coleman. Bell
Batch: no data
Purity: no data

Method

Target gene:

Histidine reversion

Species / strain

Species / strain:

other: Strains: TA98, TA100, TA1535 and TA1537

Metabolic activation:

with and without

Metabolic activation system:

Rat and hamster liver S9 induced with aroclor 1254

Test concentrations with justification for top dose:

0, 10, 33, 100, 333 and 1000 µg/plate

Vehicle:

no data

Controls

Negative controls:

no

Solvent controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Without activation : sodium azide (TA1535 and TA 100),  9-aminoacridine (TA 97), 4-nitro-o-phenylenediamine (TA98).   With activation : 2-aminoanthracene (all strains).

Details on test system and conditions:

In the Salmonella assay, a test tube containing a suspension of one  strain of Salmonella typhimurium plus S9 mix or plain buffer without S9,  is incubated for 20 minutes at 37º C with the test chemical. Control  cultures, with all the same ingredients except the test chemical, are  also incubated. In addition, positive control cultures are also prepared;  these contain the particular bacterial tester strain under investigation,  the various culture ingredients, and a known potent mutagen. After 20  minutes, agar is added to the cultures and the contents of the tubes are  thoroughly mixed and poured onto the surface of Petri dishes containing  standard bacterial culture medium. The plates are incubated for 48 hours  and then counted. The substance was tested initially in a toxicity assay to determine the  appropriate dose range. 
The toxicity assay was performed by using TA 100.  Toxic concentrations were those at which a decrease in the number of his+  colonies was seen or at which there was a clearing in the density of the  background lawn.

- Test Design   . Number of replicates : 3
- Description of follow up repeat study : same conditions than the initial experiment performed 1 week later

Evaluation criteria:

The positive control plates are counted, and the number of mutant  colonies appearing on them must be significantly increased over the  spontaneous control number for the test to be considered valid.  If no increase in mutant colonies is seen after testing several strains  under several different culture conditions, the test chemical is  considered to be non mutagenic in the Salmonella test.

Statistics:

None

Results and discussion

Test results

Key result

Species / strain:

other: Strains: TA98, TA100, TA1535 and TA1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity:

yes

Remarks:

> 1000 µg/plate

Vehicle controls valid:

yes

Negative controls valid:

not examined

Positive controls valid:

yes

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Chemical Name:	Sodium thioglycolate
CAS Number:	367-51-1
Study Type:	Salmonella
Study ID:	471613
Study Result:	Negative
Year Completed:	1979
Vehicle Control:	Water
Protocol:	Preincubation

Individual strain data is presented as mean ± standard error.

Abbreviations are noted at bottom of page.

Trial summary calls are shown in parentheses.

Strain: TA1535
Dose	No Activation		No Activation		10% HLI		10% HLI		10% RLI
	(Negative)		(Negative)		(Negative)		(Negative)		(Negative)
ug/Plate	Mean	± SEM	Mean	± SEM	Mean	± SEM	Mean	± SEM	Mean	± SEM
0	7	0.7	7	0.6	6	0.9	7	2.6	7	0.7
10	6	1	6	0.9	5	0.9	6	2	8	1.2
33	5	1.5	6	0.9	7	1.5	9	1.2	6	1.3
100	8	3.5	9	1.3	7	0.6	9	0.7	6	0.9
333	6	0.6	6	0.9	5	1.2	7	1.5	8	1.2
1000	5	1.2	8	2	5	0.3	8	1.2	8	0.9
Positive Control	288	32.3	251	40.8	106	16	43	4.1	135	9.7

Strain: TA100
Dose	No Activation		No Activation		10% HLI		10% HLI		10% RLI		10% RLI
	(Negative)		(Negative)		(Negative)		(Equivocal)		(Negative)		(Negative)
ug/Plate	Mean	± SEM	Mean	± SEM	Mean	± SEM	Mean	± SEM	Mean	± SEM	Mean	± SEM
0	100	5	110	5.8	185	26.5	179	11.7	175	27.8	189	8.7
10	95	5	126	11.4	160	18	164	6.2	140	30.4	204	37.7
33	105	31.2	129	7.5	195	30	174	7.6	170	40.9	189	3.5
100	115	10	121	3.8	220	18	221	4.2	145	18	175	9
333	125	13.2	122	8.5	160	5	173	10.1	135	8.7	221	8.1
1000	120	30	124	8.8	215	13.2	202	4.3	155	35	181	18.1
Positive Control	430	27.8	599	36.4	558	5.9	836	172.5	300	11.1	430	70.3

Applicant's summary and conclusion

Conclusions:

Under these experimental conditions, sodium thioglycolate is considered as non-genotoxic

Executive summary:

In a study performed according to the US NTP protocol, four S. typhimurium strains (TA 98, TA 100, TA 1535 and TA 1537) were exposed to sodium thioglycolate in a preincubation assay. Based on a preliminary toxicity assay, concentrations up to 1000 µg/plate were used with or without metabolic activation (rat and hamster S9) in all four strains. Sodium thioglycolate did not induce mutations in these studies. Positive and solvent controls gave the expected results.