Nitrapyrin

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:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Peer reviewed publication, no guideline followed, basic data covering two strains only

Data source

Reference

Reference Type:

publication

Title:

lmprovement and Evaluation of High Throughput Fluctuation Ames Test Using 384-well Plate with Salmonella typhimurium TA 100 and TASS

Author:

H. Sui, K. Kawakami, N. Sakurai, T Hara and T. Nohmi

Year:

2009

Bibliographic source:

Genes and Environment, Vol. 31, No. 2 pp. 47-55 (2009)

Materials and methods

Test guideline

Qualifier:

no guideline followed

GLP compliance:

not specified

Type of assay:

bacterial gene mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Nitrapyrin

EC Number:

217-682-2

EC Name:

Nitrapyrin

Cas Number:

1929-82-4

Molecular formula:

C6H3Cl4N

IUPAC Name:

2-chloro-6-(trichloromethyl)pyridine

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 98

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 100

Metabolic activation:

with and without

Metabolic activation system:

phenobarbital induced rat liver S-9

Test concentrations with justification for top dose:

no data

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Sodium azide, 4-nitroquinoline 1-oxide, 2-aminoathracene, 2-(2-furyl)-3-(5-nitro-2-furyl)acrylamide

Details on test system and experimental conditions:

Two different test methods named were conducted and compared to each other. The first method was referred to as "Ames test" the second method was referred to as "Improved FAT. The "Ames test" is based on the traditional Petri dish method, while the "Improved FAT" is based on a high throughput fluctuation Ames test, which is based on 384 microwell plates instead of the traditional method.
The advantage of the "Improved FAT" is that a much smaller amount of test chemicals is required than the Ames test and can be automated.

Ames test:
METHOD OF APPLICATION: preincubation
DURATION
- Preincubation period: 20 min at 37°C
Two plates were used for each dose, and the mean values of the two plates were calculated and used as the number of revertants


Improved FAT:
METHOD OF APPLICATION: preincubation
DURATION
- Preincubation period: 90 min at 37°C in a 24 well-plate rotating at 170 rpm. After preincubation, 2.5 mL of the histidine-deficient indicator medium was added to each well of the 24-well plate containing the reaction mixture. Before and after addition of the indicator medium, the
presence of precipitate derived from the chemicals in each weil of the 24-well plate was investigated by the naked eye. An aliquot (50 µL) of the solution (or suspension) in each well of the 24-well plate was transferred into one well of the 384-well plate for final evaluation following an additional incubation step of 72 h at 37°C-

Evaluation criteria:

For the "Ames test" method , the results were judged to be positive when the mean number of revertant colonies was increased dose dependently, and reached twice or more than that of the negative
control.
For the "Improved FAT" method, the results for TA100 were judged to be positive when the percent of positive wells was increased dose dependently, and reached twice or more than that of the negative control. With TA98, the results were judged to be positive when the percent of positive wells was increased dose dependently and reached three times or more than that of the negative control, because the percent of positive wells was low in the negative control.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with

Genotoxicity:

ambiguous

Remarks:

A week postive finding was observed for the "Ames test" method.A negative finding was observed for the "Improved FAT" method.

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 98

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 100

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.