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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1985
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study but without raw data.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1985
Report Date:
1985

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
1983
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid

Method

Species / strain
Species / strain / cell type:
other: TA 1535, 1537, 1538, 98 and 100
Details on mammalian cell type (if applicable):
strains regularly checked for their histidine requirement, ampicillin resistance (TA98 and TA100) and the frequency of spontaneous revertants
Metabolic activation:
with and without
Metabolic activation system:
S9 (following intraperitoneal injection of adult male Wistar rats of Aroclor 1524 (500 mg/kg bw) in corn oil, rats were killed by decapitation, livers were removed and the supernactant was extracted.)
Test concentrations with justification for top dose:
0, 100, 333, 1000, 3333, 5000 µg/plate
Vehicle / solvent:
DMSO excepting for positive controls: DMS for TA100, TA98 and TA1538 without activation, and for all strains with activation.
Water for TA1535 and TA1537.
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Without metabolic activation: TA 1535: sodium azide; TA 100: methylmethanesulfonate; TA 98 and TA 1538: 4-nitro-o-phenylene-diamine; TA1537: 9-aminoacridine /with metabolic activation: 2-aminoanthracene for all strains
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

EXPOSURE DURATION: 48 hours at 37 °C

NUMBER OF REPLICATIONS: 3

Results and discussion

Test resultsopen allclose all
Species / strain:
other: all strains
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Species / strain:
other: TA1535, TA1537, TA1538
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
from 1000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Species / strain:
other: TA98 and TA100
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
other: yes, but only for TA98 and from 3333 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid

Any other information on results incl. tables

  Mean number of revertant (His+), colonies /3 replicate plates WITHOUT S9
Dose (µg/plate) TA1535 TA1537 TA1538 TA98 TA100
100 7+-3 7+-4 5+-1 30+-5 125+-13
333 9+-3 5+-1 4+-1 25+-5 99+-25
1000 9+-2 6+-3 7+-3 25+-4 85+-25
3333 9+-1 9+-4 7+-3 29+-2 92+-10
5000 11+-7 10+-2 7+-3 33+-7 87+-15
Solvent control 7+-3 8+-3 7+-2 17+-2 85+-26
Positive control 320+-22 1282+-138 1163+-32 860+-141 775+-33
  Mean number of revertant (His+), colonies /3 replicate plates WITH S9
Dose (µg/plate) TA1535 TA1537 TA1538 TA98 TA100
100 10+-0 14+-2 16+-3 54+-7 168+-10
333 8+-1 (b) 20+-7(b) 17+-1(b) 90+-10 223+-23(b)
1000 0(d) 0(d) 0(d) 26+-3 334+-30(b)
3333** 0(d) 0(d) 0(d) 9*(d) 354+-211(c )
5000** 0(d) 0(d) 0(d) 14*(d) 316+-23(d)
Solvent control 8+-1 10+-1 16+-2 32+-4 91+-2
Positive control 170+-17 71+-7 1106+-22 992+-80 1787+-140
b) slightly reduced background bacterial lawn
c) moderately reduced background bacterial lawn
d) background bacterial lawn extremely reduced or absent
* 2 plates with no bacterial growth

Applicant's summary and conclusion

Conclusions:
TBEC shown mutagenic activity in the bacterial reverse mutation test with Salmonella typhimurium.
Executive summary:

The potential of TBEC to induce reverse mutation in Salmonella typhimurium (strains: TA 1535, TA 1537, TA1538, TA 98, TA 100) was evaluated in accordance with the international guidelines (OECD 471, 1986) and in compliance with the Principles of Good Laboratory Practice.

TBEC was tested in two independent experiments, with and without a metabolic activation system, according to direct plate incorporation method, without and with S9.

 

Bacterias were exposed to TBEC at six dose-levels (three plates/dose-level) selected from a preliminary toxicity test: 0, 100, 333, 1000, 3333, 5000 µg/plate. After 48 hours of incubation at 37°C, the revertant colonies were scored.

 

No cytotoxicity and no noteworth increase in the number of revertants was noted without S9.

With S9, Cytotoxicity was clearly observed from 1000 µg/plate for strains TA1535, TA1537, TA1538.

TBEC produced dose-related increases in the number of revertants of testers strains TA98 and TA100 in the presence of S9.

In conclusion, under these experimental conditions, TBEC shown mutagenic activity in the bacterial reverse mutation test with Salmonella typhimurium.