2-butanone-O,O',O''-(phenylsilylidyne)trioxime

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:

1997-05-13 to 1997-10-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Test method equivalent to OECD Guideline 471 and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

433-360-6

EC Name:

-

Cas Number:

34036-80-1

Molecular formula:

C18H29N3O3Si

IUPAC Name:

6-{[(butan-2-ylidene)amino]oxy}-3,9-dimethyl-6-phenyl-5,7-dioxa-4,8-diaza-6-silaundeca-3,8-diene

Constituent 2

Reference substance name:

2-butanone-O,O',O''- (phenylsilylidyne)trioxime

IUPAC Name:

2-butanone-O,O',O''- (phenylsilylidyne)trioxime

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): OS-9000
- Physical state: colorless to yellow liquid
- Expiration date: 13 May 1998

Method

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:

Aroclor 1254-induced rat liver S9

Test concentrations with justification for top dose:

75, 200, 600, 1800, 5000 µg/plate

Vehicle / solvent:

Solvent: Dimethyl sulfoxide (DMSO)

Controls

Controls 1

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Controls 2

Positive controls:

yes

Remarks:

With S9, Salmonellal strains and WP2 uvrA

Positive control substance:

other: 2-aminoanthracene

Remarks:

1.0 µg/plate (Salmonella), 10 µg/plate (WP2 uvrA)

Controls 3

Positive controls:

yes

Remarks:

Without S9; TA98

Positive control substance:

2-nitrofluorene

Remarks:

1.0 µg/plate

Controls 4

Positive controls:

yes

Remarks:

Without S9; TA100 andTA1535

Positive control substance:

sodium azide

Remarks:

1.0 µg/plate

Controls 5

Positive controls:

yes

Remarks:

Without S9; TA1537

Positive control substance:

9-aminoacridine

Remarks:

75 µg/plate

Controls 6

Positive controls:

yes

Remarks:

Without S9; WP2 uvrA

Positive control substance:

methylmethanesulfonate

Remarks:

1000 µg/plate

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)
Overnight cultures were prepared by inoculating into a vessel containing ~50 mL of culture medium. Following inoculation, each flask was placed in a resting shaker/incubator at room temperature (125 rpm at 37±2 ºC) 12 hours before the anticipated time of harvest. Each culture was monitored spectrophotometrically for turbidity and was harvested at a percent transmittance yielding a titer of approximately 10E+09 cells/mL. The actual titers were determined by viable count assays on nutrient agar plates.

Test article dilutions were prepared immediately before use. One-half (0.5) mL of S9 or Sham mix, 100 µL of tester strain and 50 pL of vehicle or test article were added to 2.0 mL of molten selective top agar at 45±2 ºC. After vortexing, the mixture was overlaid onto the surface of 25 mL of minimal bottom agar. When plating the positive controls, the test article aliquot was replaced by a 50 µL aliquot of appropriate positive control. After the overlay had solidified, the plates were inverted and incubated for approximately 48 to 72 hours at 37±2 ºC. Plates that were not counted immediately following the incubation period were stored at 4±2 ºC until colony counting could be conducted.

DURATION
- Exposure duration:
- Expression time (cells in growth medium):
- Selection time (if incubation with a selection agent):
- Fixation time (start of exposure up to fixation or harvest of cells):

SELECTION AGENT (mutation assays):
SPINDLE INHIBITOR (cytogenetic assays):
STAIN (for cytogenetic assays):

NUMBER OF REPLICATIONS:

NUMBER OF CELLS EVALUATED:

DETERMINATION OF CYTOTOXICITY
The condition of the bacterial background lawn was evaluated for evidence of test article toxicity by using a dissecting microscope.
Revertant colonies for a given tester strain and activation condition were counted either entirely by automated colony counter or entirely by hand unless the assay was the preliminary toxicity assay or the plate exhibited toxicity. Plates with sufficient test article precipitate to interfere with automated colony counting were counted manually.

OTHER EXAMINATIONS:
Precipitate was evaluated by visual examination without magnification.

OTHER:

Evaluation criteria:

For the test article to be evaluated positive, it must cause a dose-related increase in the mean revertants per plate of at least one tester strain with a minimum of two increasing concentrations of test article. Data sets for strains TA1535 and TA1533 were judged positive if the increase in mean revertants at the peak of the dose response is equal to or greater than three times the mean vehicle control value. Data sets for strains TA98, TA100 and WP2 uvrA were judged positive if the increase in mean revertants at the peak of the dose response is equal to or greater than two times the mean vehicle control value.

Statistics:

For each replicate plating, the mean and standard deviation of the number of revertants per plate were calculated and are reported.

Results and discussion

Test results

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES: The preliminary toxicity assay was used to establish the dose-range over which the test article would be assayed. Ten dose levels of the test article (up to 5000 µg/plate) were plated, one plate per dose, with overnight cultures of TA98, TA100, TA1535, TA1537 and WP2 uvr4 on selective minimal agar in both the presence and absence of rat liver S9 activation. Precipitate was observed at 13333 µg/plate but no appreciable toxicity was observed. Based on the findings of the toxicity assay, the maximum dose plated in the mutagenicity assay was 5000 µg/plate.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Salmonella/E. coli Mutagenicity Assay

With metabolic activation (liver microsomes)

Dose	TA90	TA100	TA1535	TA1537	WP2 uvrA
0	12±1	206±16	11±5	9±2	25±1
75	19±2	200±47	9±3	11±2	18±2
200	19± 3	228±7	11±1	12±2	16±2
600	14±4	230±1	11±0	13±1	18±1
1800	17±4	198±34	13±2	10±5	13±3
5000	13±3	171±25	20±1	6±1	10±0
Positive	164±8	724±28	534±27	1273±46	132±4

               

Without metabolic activation

Dose	TA90	TA100	TA1535	TA1537	WP2 uvrA
0	23±2	192±25	13±2	12±2	19±5
75	20±5	198±11	17±6	12±5	15±5
200	17±3	197±22	14±2	7±3	17±5
600	18±5	225±14	13±1	11±2	14±1
1800	18±3	201±29	17±1	10±2	25±2
5000	19±3	212±34	18±5	9±1	17±1
Positive	462±35	795±34	102±12	96±17	253±9

Precipitate was generally observed at >= 1800 µg/plate but no appreciable toxicity was observed.

No positive responses were observed with any of the tester strains in the presence and absence of S9 activation.

All the validity criteria were fulfiled.

The results of the Bacterial Reverse Mutation Assay with an Independent Repeat Assay indicate that, under the conditions of this study, test substance did not cause a positive response with any of the tester strains in the presence and absence of metabolic activation.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Under the conditions of this study, test substance did not cause a positive response with any of the tester strains in the presence and absence of metabolic activation.

Executive summary:

A bacterial reverse mutation assay was performed in an equivalent method to OECD 471 with S. typhimurium tester strains TA98, TA100, TA1535 and TA1537 and E. coli tester strain WP2 uvrA in the presence and absence of Aroclor-induced rat liver S9. The assay was performed in two phases, using the plate incorporation method. Based on the findings of the toxicity assay, the maximum dose plated in the mutagenicity assay was 5000 µg per plate. In the mutagenicity assay, no positive response was observed. Precipitate was generally observed at >=1800 µg per plate but no appreciable toxicity was observed. All the validity criteria were fulfiled. Under the conditions of this study, test article was concluded to be negative in the Bacterial Reverse Mutation Assay with an Independent Repeat Assay.