Registration Dossier

Diss Factsheets

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
other information
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
significant methodological deficiencies
Remarks:
Non standard method of application which makes uncertain the concentration tested

Data source

Reference
Reference Type:
publication
Title:
Dichloroacetic acid and related compounds: induction of prophage in E. coli and mutagenicity and mutation spectra in Salmonella TA100
Author:
David M.DeMarini, Erica Perry and Melissa L.Shelton
Year:
1994
Bibliographic source:
Mutagenesis, vol. 9 no. 5, pages 429-437

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
only TA100 tested, vaporization technique, few information available
Principles of method if other than guideline:
The mutagenicity of Trichloroacetyl chloride (TCAC) (volatilde compound) in strain TA100 of Salmonella was evaluated using the vaporization technique (Hughues et al., 1987).
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Trichloroacetyl chloride
EC Number:
200-926-7
EC Name:
Trichloroacetyl chloride
Cas Number:
76-02-8
Molecular formula:
C2Cl4O
IUPAC Name:
trichloroacetyl chloride
Test material form:
liquid
Details on test material:
Purity: 99%
No other information was available.
Specific details on test material used for the study:
Trichloroacetyl chloride was purchased from Aldrich (Milwaukee, WI, USA).

Method

Target gene:
TA100 contains the base-substitution allele hisG46, which is the only allele of the Ames Salmonella strains that has detected the mutagenic activity of TCAC.
Species / strain
Species / strain / cell type:
S. typhimurium TA 100
Metabolic activation:
with and without
Metabolic activation system:
post-mitochondrial fraction (S9 fraction) obtained from a liver microsomal fraction of rats induced with Aroclor 1254
Test concentrations with justification for top dose:
With S9: 0, 100, 200, 300, 400 ppm
Without S9: 0, 100, 200, 300, 400, 500, 600, 700 ppm
Vehicle / solvent:
no data
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
other: 2-aminoanthracene
Details on test system and experimental conditions:
2.5 mL of top agar containing 100 µL of an overnight culture of strain TA100 (+/- 500 µL of S9 mix) were poured onto 50 mL of minimal medium in a 100-mm glass petri dish. After the top agar had hardened, the bottom and top parts of the petri dish were placed against each other, and the assembly was inserted into a Tedlar bag of known volume (600 - 800 mL) with the inverted top of the dish directly under the septum of the bag. The bag was then sealed, and various amounts of the test compound were injected through a septum on the bag into the inverted top of the petri dish. The bag was placed in a 37°C incubator for 24 h, after which the bag was opened, the two halves of the petri were reassembled, and the inverted plate was placed back in the incubator for an additional 48 h. Colonies were counted by an automatic colony counter (biotran II).
Each petri plate was in a separate bag, and two plates were exposed at each concentration of chemical tested. All experiments were performed at least twice. The concentration (p.p.m.) of the test chemical in the bag was calculated based on the volume of the bag and the amount (µL) and density (g/mL) of the test chemical injected into the bag.
A reproducible, 2-fold increase in revertants/plate relative to the background was considered a positive response.
Statistics:
Chi-square analysis

Results and discussion

Test results
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Trichloroacetyl chloride (TCAC) was tested to toxicity as indicated by a reduction in the number of revertants/plate relative to the background and/or a thinning of the background lawn of cells. TCAC (+/- S9) gave reproducible, mutagenic responses.
S9 had no effect on the mutagenic potency of TCAC.

Any other information on results incl. tables

Table 1: Mutagenic potencies of chemicals in Salmonella TA100

 

Chemicala

Revertants/p.p.m. (r²)a

LECb

Experiment 1

Experiment 2

Mean

TCAC (- S9)

0.5 (0.99)

0.8 (0.84)

0.7

300

TCAC (+ S9)

0.9 (0.92)

0.7 (0.82)

0.8

200

a: Potencies are the slopes of the regression calculated over the linear portion of the dose-response curves in Figure 1.

b: Lowest effective concentration, i.e. the concentration (p.p.m.) producing a 2 -fold increase in rev/plate relative to the background.

Applicant's summary and conclusion

Conclusions:
In these test conditions, Trichloroacetyl chloride is mutagenic for the strain TA100 with and without metabolic activation.
Executive summary:

The mutagenicity of Trichloroacetyl chloride (TCAC) (volatilde compound) in strain TA100 of Salmonella typhimurium with and without metabolic activation, was evaluated using the vaporization technique.

TCAC was tested to toxicity as indicated by a reduction in the number of revertants/plate relative to the background and/or a thinning of the background lawn of cells. TCAC (+/- S9) gave reproducible, mutagenic responses.

In these test conditions, TCAC is mutagenic for the strain TA100 with and without metabolic activation.