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Toxicological information

Genetic toxicity: in vitro

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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:
1992
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and OECD testing guideline compliant study with well characterized test material

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
adopted May 26, 1983
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Substance type: Organic
- Physical state: Solid
- Lot/batch No.: Z-2281/1,2,4,5
- Expiration date of the lot/batch: April 01, 1997
- Storage condition of test material: at room temperature in the dark

Method

Target gene:
His: Salmonella
Trp: E. Coli
Species / strain
Species / strain / cell type:
other: Salmonella typhimurium strains: TA100, TA98, TA1535, TA1537; E. coli : WP2uvrA and WP2
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced rat liver S9 mix
Test concentrations with justification for top dose:
10; 100; 333.3; 1000; and 5000 µg/plate
Vehicle / solvent:
Dimethyl sulfoxide
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: see: "Details on test system and conditions"
Details on test system and experimental conditions:
POSITIVE CONTROLS:
Without metabolic activation (-S9-mix):
TA1535, TA 100: sodium azide (SA), 10 µg
TA1537, TA 98: 4-nitro-o-phenylene-diamine, 4-NOPD 50 µg
WP2uvrA, WP2 : methylmethanesulfonate (MMS), 10 µl


With metabolic activation (+S9-mix):
TA1537, : 2-aminoanthracene (2AA), 2.5 µg
TA1535, TA 1537, TA98 and TA100: 2-aminoanthracene (2AA), 2 µg
WP2uvrA and WP2: 2-aminoanthracene (2AA), 2 µg

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Incubation period: 48 hours. After this period revertant colonies (histidine independent for Salmonella typhimurium bacteria and tryptophan independent for Escherichia coli) were counted.
- COLONY COUNTING:
- Exposure duration: The revertant colonies (histidine independent/ tryptophan independent) were counted automatically with a Protos model 50000 colony counter or manually, if less than 40 colonies per plate were present. Plates with sufficient test article precipitate to interfere with automated colony counting were counted manually.

NUMBER OF REPLICATIONS: 3
Evaluation criteria:
A test article is considered as mutagenic if in the strains TA 100, WP2, and its uvrA derivate the number of reversions will
be at least twice as high and in the strains TA 1535, TA 1537, and TA 98 it will be at least three times higher as compared to
the spontaneous reversion rate.
Also, a dose-dependent increase in the ntimber of revertants isregarded as an indication of possibly existing mutagenic potential
of the test article regardless whether the highest dose induced the above described enhancement factors or not.

Results and discussion

Test results
Species / strain:
other: Salmonella typhimurium strains: TA100, TA98, TA1535, TA1537; E. coli : WP2uvrA and WP2
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
in strain TA 1535 at 5000 µg/plate without S9 mix in experiment I.
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
PRECIPITATE: Not mentioned.

TOXICITY: Toxic effects evidenced by a reduction in revertant colony numbers occurred only in strain TA 1535 at 5000 µg/plate without S9 mix in experiment I. The plates incubated with the test article showed normal background growth up to 5000 µg/plate with and without metabolic activation in both independent experiments.

MUTAGENICITY: No increase in the number of revertants was observed upon treatment with the test substance under all conditions tested. All bacterial strains showed negative responses over the entire dose range, i.e. no dose-related, two-fold, increase in the number of revertants in two independently repeated experiments.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Number of revertants in the control or after treatment with the test substance


First experiment (10 - 5000 µg/plate)
Strain Metabolic activation system mean revertants in Controls maximum revertant factor dose dependency Assessment
TA 1535 no 15 1.1 no negative
  yes 15 1.2 no negative
TA 1537 no 6 1.1 no negative
  yes 6 1.4 no negative
TA 98 no 20 1.2 no negative
  yes 33 1.2 no negative
TA 100 no 78 0.9 no negative
  yes 88 1.1 no negative
E. coli WP2 uvrA no 38 1.2 no negative
  yes 41 1.1 no negative
E. coli WP2 noyes 3040 1.61.2 nono negativenegative
Second experiment (10 - 1000 µg/plate)
Strain Metabolic activation system mean revertants in Controls maximum revertant factor dose dependency Assessment
TA 1535 no 14 1.1 no negative
  yes 15 1.2 no negative
TA 1537 no 11 1.2 no negative
  yes 15 1.2 no negative
TA 98 no 24 1.2 no negative
  yes 41 1.3 no negative
TA 100 no 90 1.1 no negative
  yes 91 1.0 no negative
E. coli WP2 uvrA no 39 1.4 no negative
  yes 47 1.1 no negative
 E. coli WP2  no  57  1.1  no negative 
   yes  56  1.1  no  negative
           
           
           

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative