O,O-bis(methylphenyl) hydrogen dithiophosphate

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:

2012

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

O,O-bis(methylphenyl) hydrogen dithiophosphate

EC Number:

248-273-7

EC Name:

O,O-bis(methylphenyl) hydrogen dithiophosphate

Cas Number:

27157-94-4

Molecular formula:

C14H15O2PS2

IUPAC Name:

O,O-bis(2-methylphenyl) sulfanylphosphonothioate

Constituent 2

Reference substance name:

Phosphorodithioic acid, O,O-bis(methylphenyl) ester

IUPAC Name:

Phosphorodithioic acid, O,O-bis(methylphenyl) ester

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): Cresyl-P1
- Physical state: Liquid
- Stability under test conditions: Stable
- Storage condition of test material: ambient

Method

Target gene:

Strain Designation Histidine Gene Locus Affected Additional Mutations Type of Mutation Detected
Repair LPS Plasmids
TA 98#1 his D 3052 uvr B- rfa- pKM 101 Frameshift
TA 100#1 his G 46 uvr B- rfa- pKM 101 Base-pair substitution
TA 102#1 his G 428 wild-type rfa- pKM 101 / pAQ1 Base-pair substitution
TA 1535#2 his G 46 uvr B- rfa- none Base-pair substitution
TA 1537#2 his C 3076 uvr B- rfa- none Frameshift


rfa-: partial loss of lipopolysaccharide (LPS) barrier that causes increased permeability to macromolecules
uvr B-: loss of DNA excision repair system
pKM 101: R-factor plasmid, thought to cause an increased error-prone DNA repair
pAQ1: plasmid, carrier of tetracycline resistance
#1 resistance to Ampicillin
#2 non-resistance to Ampicillin

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Metabolic activation system:

a microsomal preparation derived from Aroclor 1254-induced rat liver.

Test concentrations with justification for top dose:

5.0, 15.8, 50, 158, 500 and 1580 µg per plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: ethanol (Batch no. B1810; Honeywell Specialty Chemicals Seelze GmbH, 30926 Seelze Germany)

- Justification for choice of solvent/vehicle: Cresyl-P1 (DANAFLOAT™ 070) was not soluble in dimethyl sulfoxid (DMSO), water, methanol or acetone.

Controls

Controls 1

Untreated negative controls:

yes

Remarks:

ethanol

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

in aqua ad iniectabilia (10 µg/plate) : TA 1535, TA 100

Controls 2

Untreated negative controls:

yes

Remarks:

ethanol

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

in DMSO (10 µg/plate) : TA 98

Controls 3

Untreated negative controls:

yes

Remarks:

ethanol

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

in ethanol, abs. (100 µg/plate) : TA 1537

Controls 4

Untreated negative controls:

yes

Remarks:

ethanol

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

in DMSO (10 µg/plate) : TA 102

Controls 5

Untreated negative controls:

yes

Remarks:

ethanol

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Remarks:

in DMSO (10 µg/plate) : TA 98, TA 102, TA 1537

Controls 6

Untreated negative controls:

yes

Remarks:

ethanol

Positive controls:

yes

Positive control substance:

other: 2-amino-anthracene

Remarks:

in DMSO (2 µg/plate) : TA 100, TA 1535

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Preincubation period: 20 minutes at 37°C
- Exposure duration: 48-72 hours at 37°C

Evaluation criteria:

A test item is considered to show a positive response if
- the number of revertants is significantly increased (p ≤ 0.05, U-test according to MANN and WHITNEY, see COLQUHOUN, D.: Lectures on Biostatistics, Clarendon Press, Oxford (1971)) compared with the solvent control to at least 2-fold of the solvent control for TA 98, TA 100 and TA 102 and 3-fold of the solvent control for TA 1535 and TA 1537 in both independent experiments;
- in addition, a significant (p ≤ 0.05) concentration (log value)-related effect (Spearman’s rank correlation coefficient, see COLQUHOUN, D.: Lectures on Biostatistics, Clarendon Press, Oxford (1971)) is observed;
- positive results have to be reproducible and the histidine independence of the revertants has to be confirmed by streaking random samples on histidine-free agar plates.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 6

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Remarks:

No increase in revertant colony numbers as compared with control counts was observed for test item, tested up to a cytotoxic concentration of 3250 µg/plate, in any of the 5 test strains in two independent experiments w./wo metabolic activation, respective

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

In the plate incorporation test and the preincubationcubation test, each carried out without and with metabolic activation cytotoxicity (scarce background lawn and reduction of the number of revertants) was noted at the top concentration of 1580 µg /plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

It can be concluded that the test material is negative with and without metabolic activation in all tester strains.

Under the present test conditions Cresyl-P1 tested up to a cytotoxic concentration of 1580 µg Cresyl-dtp/plate, caused no mutagenic effect in the Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 neither in the plate incorporation test nor in the preincubation test each carried out without and with metabolic activation.

Executive summary:

The registered substance was tested for its mutagenicity in an Ames Plate Incorporation Assay according to OECD Guideline 471 and under GLP in Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 with and without metabolic activation.
Under the present test conditions Cresyl-P1 tested up to a cytotoxic concentration of 1580 µg Cresyl-dtp/plate, caused no mutagenic effect in the Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 neither in the plate incorporation test nor in the preincubation test each carried out without and with metabolic activation.