Benzothiazole

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:

1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

: only 4 strains tested

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Benzothiazole

EC Number:

202-396-2

EC Name:

Benzothiazole

Cas Number:

95-16-9

Molecular formula:

C7H5NS

IUPAC Name:

benzothiazole

Details on test material:

- Name of test material (as cited in study report): benzothiazole
- Analytical purity: 97.4 %
- Purity test date: May 21, 1991
- Lot/batch No.: 90 B 0521
- Other: Sample No.: 105488/1990; Product No.:680982

Method

Target gene:

His operon

Species / strain

Species / strain / cell type:

other: S. typhimurium TA 98, TA 100, TA 1535, TA 1537

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

8, 40, 125, 200, 250, 500, 1000, 2000, 4000, 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: ethylene glycol dimethylether (EGDE) for benzothiazole and DMSO for the positive controls
- Justification for choice of solvent/vehicle: for EGDE: sufficient evidence was available in the literature (Maron and Ames, 1983)

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

Migrated to IUCLID6: 10 µg per plate were used without S9 mix

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: nitrofurantoin: 0.2 µg per plate were used without S9 mix

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-1,2-phenylene diamine: 0.5 (in TA 98) and 10 µg per plate (in TA 1537) were used without S9 mix

Controls 4

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene: 3 µg per plate were used with S9 mix

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hours
- Expression time (cells in growth medium): 17 hours
- Selection time (if incubation with a selection agent): 48 hours


DETERMINATION OF CYTOTOXICITY
- Method: other: reduction in background growth; marked and dose-dependent reduction in the mutant count per plate and the titer was determined

Evaluation criteria:

A reproducible and dose-related increase in mutant counts of at least one strain is considered to be a positive result. For TA 1535, TA 100 and TA 98 this increase should be about twice the amount of negative controls, whereas for TA 1537, at least a threefold increase should be reached. Otherwise, the result is evaluated as negative.

Statistics:

no data

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:

cytotoxicity

Remarks:

at 1000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: other: S. typhimurium TA 98, TA 100, TA 1535, TA 1537

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Summary of results with benzothiazole

S9 mix	TA 1535	TA 100	TA 1537	TA 98
Without	Negative	Negative	Negative	Negative
With	Negative	Negative	Negative	Negative

Summary of mean values without S9 mix

With or without S9-Mix	Test substance concentration (µg/plate)	Mean number of revertant colonies per plate (average of 4 parallel testings)
		Base-pair substitution type		Frameshift type
		TA 1535	TA 100	TA 1537	TA 98
-	0	17	102	8	32
-	8	12	107	9	38
-	40	16	117	9	33
-	200	17	115	11	32
-	1000	10	107	13	32
-	5000	/	20	5	2
Positive controls - S9	Name	Na-azid	NF	4-NPDA	4-NPDA
	Concentrations (µg/plate)	10	0.2	10	0.5
	Number of colonies/plate	470	312	46	103
		TA 1535	TA 100	TA 1537	TA 98
-	0	14	65	8	29
-	125	13	60	10	25
-	250	15	66	7	23
-	500	12	52	9	22
-	1000	12	61	9	20
-	2000	12	60	6	15
-	4000	9	36	3	9
Positive controls - S9	Name	Na-azid	NF	4-NPDA	4-NPDA
	Concentrations (µg/plate)	10	0.2	10	0.5
	Number of colonies/plate	610	241	46	68

Na-azid = sodium azide

NF = nitrofurantoin

4 -NPDA = 4 -nitro-1,2 -phenylene diamine

Summary of mean values with S9 mix

With or without S9-Mix	Test substance concentration (µg/plate)	Mean number of revertant colonies per plate (average of 4 parallel testings)
		Base-pair substitution type		Frameshift type
		TA 1535	TA 100	TA 1537	TA 98
+	0	26	151	16	39
+	8	19	144	13	37
+	40	15	143	13	45
+	200	15	150	13	44
+	1000	16	131	8	30
+	5000	9	29	6	4
Positive controls + S9	Name	2-AA	2-AA	2-AA	2-AA
	Concentrations (µg/plate)	3	3	3	3
	Number of colonies/plate	132	615	117	234
		TA 1535	TA 100	TA 1537	TA 98
+	0	22	152	17	45
+	125	24	123	17	36
+	250	19	149	16	41
+	500	17	130	17	36
+	1000	18	109	18	38
+	2000	16	88	17	34
+	4000	8	82	9	21
Positive controls + S9	Name	2-AA	2-AA	2-AA	2-AA
	Concentrations (µg/plate)	3	3	3	3
	Number of colonies/plate	234	762	81	731

2-AA = 2-aminoanthracene

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative no classification required

Executive summary:

Gahlmann (Bayer AG), 1991

The mutagenic activity of benzothiazole was investigated in a bacterial gene mutation assay conducted comparable to OECD-guideline 471 with acceptable restrictions (only 4 strains used). The plate incorporation method was performed with Salmonella typhimurium TA98, TA 100, TA1535 and TA1537 both in presence and absence of a metabolic activator at 8, 40, 125, 200, 250, 500, 1000, 2000, 4000, 5000 µg benzothiazole per plate. Under these conditions no mutagenic activity was reported in strains TA 98, TA 100, TA 1535, or TA1537. Therefore no classification is required.