Registration Dossier

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
Histidine (S. typhimurium) and Tryptophane (E. coli)
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Metabolic activation:
with and without
Metabolic activation system:
S9 fraction (microsome fraction prepared from Sprague Dawley rat liver homogenate)
Test concentrations with justification for top dose:
50, 150, 500, 1500, 5000 ug/plate
Vehicle / solvent:
water
Controls
Untreated negative controls:
yes
Positive controls:
yes
Positive control substance:
7,12-dimethylbenzanthracene
9-aminoacridine
2-nitrofluorene
sodium azide
other: 2-anthramine, cis-Platinum (II) Diammine Dichloride
Details on test system and experimental conditions:
The genotype of bacterial strains is checked:
-Histidine and tryptophane requirements with cultures in presence and in absence of L-histidine and L-triptophane for Salmonella typhimurium and Escherichia coli strains respectively.
-Loss of cell wall LPS (rfa mutation) measuring crystal violet inhibition for Salmonella typhimurium strains.
-Ampicillin resistance for the strains which have the pKM 101 plasmide.
-uvr B mutation i.e. U.V.B sensitivity for Salmonella typhimurium and uvr A mutation i.e. U.V.A sensitivity for Escherichia coli.
-Spontaneous revertant rate.
-Sensitivity to reference mutagens
Evaluation criteria:
- the bacteriostatic activity of the highest concentration tested shall be equal to or less than 75 %,
- the spontaneous reversion rate of the absolute negative control shall comply with the historical values of the laboratory,
- the spontaneous reversion rate of the solvent shall not be statistically different from absolute negative control,
- the mean number of revertant colonies obtained for each strain and the corresponding positive control, with and/or without metabolic activation shall comply with the historical values of the laboratory.
- Negative and positive values should not show significant difference with the historical values of the laboratory (± 2 standard deviations).

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Untreated negative controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Doses (5 000, 1 500, 500, 150 and 50 μg/plate) performed from solutions of the test item Whey, lactose-low do not induce any mutagenic change in Salmonella typhimurium TA 1535, TA 1537, TA 98, TA 100 and in Escherichia coli WP2(uvrA-) (pKM 101) without, or with metabolic activation, according to the OECD Guidelines n°471.