Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

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:
other: Non GLP, near guideline study, some restrictions in reporting but adequate for assessment

Data source

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

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
E. coli not included
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- BASF test substance number: 83/142
- Storage +4°C
- No further details

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
other: TA 98 and TA 100 have a modified post replication DNA repair system
Metabolic activation:
with and without
Metabolic activation system:
Aroclor induced rat liver S9
Test concentrations with justification for top dose:
0, 20, 100, 200, 300, 400, 500, 2500 and 5000 µg/plate
Vehicle / solvent:
- DMSO
Controlsopen allclose all
Untreated negative controls:
yes
Remarks:
sterility control
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
other:
Remarks:
all strains, with S9
Positive controls:
yes
Positive control substance:
other:
Remarks:
TA 100 and TA 1535, without S9
Positive controls:
yes
Positive control substance:
other:
Remarks:
TA 98, without S9
Positive controls:
yes
Positive control substance:
other: 100 μg 9-aminoacridine chloride monohydrate
Remarks:
TA 1537, without S9
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)
- Standard plate test: Test tubes containing 2 mL of soft agar (100 ml agar (0.6% agar + 0.6% NaCl) and 10 mL amino-acid solution: 0.5 mM histidine + 0.5 mM biotin) kept in a water bath at 45°C, and the remaining components are added in the following order: 0.1 mL test solution; 0.1 mL bacterial suspension; 0.5 mL S-9 mix (in tests with metabolic activation) or 0.5 mL phosphate buffer (in tests without metabolic activation).
- After mixing, the samples are poured onto the Vogel-Bonner agar plates (minimal glucose agar plates) within approx. 30 seconds.
- Preincubation test: 0.1 mL test solution, 0.1 mL bacterial suspension and 0.5 mL S-9 mix incubated at 37°C for the duration of 20 minutes. Subsequently, 2 mL of soft agar is added, and, after mixing, the samples are poured onto the Vogel-Bonner agar plates within approx. 30 seconds
- After incubation for 48 hours at 37°C in the dark, the bacterial colonies (his+ revertants) are counted.

NUMBER OF REPLICATIONS:
- For each test, 3 plates per dose or per control.

DETERMINATION OF CYTOTOXICITY
- Yes

CHECKING OF TESTER STRAINS
- The Salmonella strains are checked for the following characteristics at regular intervals: deep rough character (rfa); UV sensitivity (∆ uvrB); ampicillin resistance (R factor plasmid) .
- Histidine auxotrophy is automatically checked in each experiment via the spontaneous rate.

Evaluation criteria:
A substance is characterised as positive if it fulfils the following requirements: doubling of the spontaneous mutation rate (control); dose-response relationship; reproducibility of the results.
Statistics:
None specified.

Results and discussion

Test resultsopen allclose all
Species / strain:
other: S. typhimurium TA 1535 and TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
No increase in the number of his+ revertants
Vehicle controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
ambiguous
Remarks:
Only in 2 standard plate tests was a slight increase in the number of revertant colonies at 100 - 200µg by a factor 1.5-1.9 detected after metabolic activation.
Vehicle controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
other: In all 4 standard plate tests with S-9 mix a slight increase in the number of his+ revertants by a factor of 1.4-1.7 was observed at 100-200 µg/plate
Vehicle controls validity:
valid
Positive controls validity:
valid

Any other information on results incl. tables

Clear bacteriotoxic effect (reduced his- background growth, decrease in the number of his+ revertants) at doses ≥200 µg/plate.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative with and without metabolic activation

Rohnaphthalin-gemisch (CAS 85117-10-8) was negative with and without metabolic activation when tested in a bacterial reverse mutation assay.

Executive summary:

Rohnaphthalin-gemisch (CAS 85117-10-8) was tested in a bacterial reverse mutation test using Salmonella typhimurium tester strains TA98, TA100, TA1535 and TA1537 in the presence and absence or Aroclor-induced rat liver S9.

Toxicity was observed with some conditions at > 200 µg/plate. Small increases in revertant colonies seen in strains TA98 and 100, in only some of the experiments, were not seen on changing the test conditions (pre-incubation test to try to optimise any activity that may be present).  The increases in revertant colonies seen do not meet the criteria for a positive response and are considered not to indicate a mutagenic effect of the test material.

Rohnaphthalin-gemisch (CAS 85117-10-8) did not induce a significant increase in revertant colonies in Salmonella strains with or without rat liver metabolic activation at any dose level and is considered not to be a mutagen in this test system.