Saccharomyces cerevisiae, ext.

Genetic toxicity: in vitro

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:

15-20 March 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: According to GLP and OECD 471, with one exception: negative test result not confirmed in an independent repeat test. Test performed with a surrogate which has a comparable composition.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

negative test result not confirmed in an independent repeat test

Principles of method if other than guideline:

The test was performed using the plate incorporation assay.

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Gistex Standard Powder AGGL

IUPAC Name:

Gistex Standard Powder AGGL

Details on test material:

- Name of test material (as cited in study report): Gistex Standard Powder AGGL
- Molecular formula (if other than submission substance): no data
- Molecular weight (if other than submission substance): no data
- Smiles notation (if other than submission substance): no data
- InChl (if other than submission substance): no data
- Structural formula attached as image file (if other than submission substance): no data
- Substance type: powder
- Physical state: solid
- Analytical purity: no data
- Impurities (identity and concentrations): no data
- Composition of test material, percentage of components: no data
- Isomers composition: no data
- Purity test date: no data
- Lot/batch No.: PHS2 A04
- Expiration date of the lot/batch: 4 August 2000
- Radiochemical purity (if radiolabelling): not relevant
- Specific activity (if radiolabelling): not relevant
- Locations of the label (if radiolabelling): not relevant
- Expiration date of radiochemical substance (if radiolabelling): not relevant
- Stability under test conditions: no data
- Storage condition of test material:
- Other:

Method

Target gene:

Reversion from his- to his+

Species / strain

Species / strain / cell type:

other: TA-1535, TA-1537, TA-1538, TA-98, TA-100 & E. coli WP2 uvrA

Metabolic activation:

with and without

Metabolic activation system:

S9 mix from livers of Aroclor 1254 induced male rats

Test concentrations with justification for top dose:

62, 185, 556, 1667 and 5000 µg/plate (with and without S9)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: the test substance was soluble in water up to the highest test concentration

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: without S9: sodium azide (TA-1535, TA-100), 2-nitrofluorene (TA-98), 9-aminoacridine (TA-1537), N-ethyl-N-nitrosourea (WP2 uvrA); with S9: 2-aminoanthracene (all strains except TA 1537), benzo(a)pyrene (TA1537)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)
DURATION
- Exposure duration: 72 hours
NUMBER OF REPLICATIONS: 3 plates per strain per concentration (with S9 and without S9)
DETERMINATION OF CYTOTOXICITY
- Method: reduction in number of revertant colonies and/or clearing of background lawn of bacterial growth

Evaluation criteria:

The assay was considered valid if the mean colony counts of the control are within acceptable ranges and if the results of the positive control meet the criteria for a positive response.
A response was considered positive if the mean number of revertant colonies on the test plates is increased two-fold or more compared to that on the negative control plates.
A test substance was considered to be mutagenic if a concentration related increase or if a reproducible positive response is observed.

Statistics:

None.

Results and discussion

Test results

Species / strain:

other: all tested strains

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: none observed
- Other confounding effects: none
RANGE-FINDING/SCREENING STUDIES: not relevant

COMPARISON WITH HISTORICAL CONTROL DATA: the mean colony counts of the controls were within acceptable ranges and the results of the positive control met the criteria for a positive response.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

The results are summarised in the table below, which shows the mean number of revertants of 3 plates.

dose	TA1535		TA1537		TA98		TA100		E. coli
(ug/plate)	-S9	+S9	-S9	+S9	-S9	+S9	-S9	+S9	-S9	+S9
0	14	18	7	14	29	40	162	145	31	34
62	15	13	9	19	29	40	128	136	25	34
185	12	14	7	12	26	37	122	132	22	30
556	11	11	10	17	35	57	133	132	22	35
1667	22	21	12	17	33	51	145	179	26	31
5000	24	19	6	17	35	55	146	194	25	30
pos cont.	1068	294	907	226	1113	608	1004	1464	274	1073

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

In an Ames test (plate incorporation assay) according to OECD 471, the test substance was negative in all 5 tester strains in the presence and absence of metabolic activation (S9 mix from livers of Aroclor 1254 induced rats). The negative result was not confirmed in an independent repeat test.