Propiononitrile

Genetic toxicity: in vitro

Administrative data

Endpoint:

genetic toxicity in vitro, other

Remarks:

genetic toxicity to Saccharomyces cerevisiae

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference

Reference Type:

publication

Title:

The influence of solvent stress on MMS-induced genetic change in Saccharomyces cerevisiae

Author:

Zimmermann, Friedrich K.
Rohlfs, Anja

Year:

1991

Bibliographic source:

Zimmermann, F.K. & Rohlfs, A., 1991. The influence of solvent stress on MMS-induced genetic change in Saccharomyces cerevisiae. Mutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 250(1–2), pp.239–249.

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The genetic toxicity (mitotic recombination and mitotic chromosome loss) of several solvents, including propionitrile, to the yeast Saccharomyces cerevisiae was examined.

GLP compliance:

not specified

Type of assay:

yeast cytogenetic assay

Test material

Test material information

Constituent 1

Reference substance name:

Propiononitrile

EC Number:

203-464-4

EC Name:

Propiononitrile

Cas Number:

107-12-0

Molecular formula:

C3H5N

IUPAC Name:

propanenitrile

Specific details on test material used for the study:

propionitrile (98%, CAS No. 107-12-0, Roth, Karlsruhe)

Method

Species / strain

Species / strain / cell type:

Saccharomyces cerevisiae

Details on test system and experimental conditions:

Induction of mitotic chromosome loss was tested in the diploid strain D61.M (Zimmermann et al., 1985a). This strain is heterozygous for recessive markers flanking the centromere of chromosome VII. There is a selective marker, cyh2, which causes a resistance to 1.7 ppm cycloheximide. A colony color marker is ade6 which is located on the opposite side of the centromere and when expressed changes the red colony color caused by the homozygous condition of ade2 to white. Chromosome loss is indicated when at least 30% of such white resistant colonies simultaneously express centromcre marker leu1. Chemicals inducing only chromosome loss cause an increase of only white but not red colonies on the selective cycloheximide medium, and the vast majority of those white colonies express the recessive centromere marker leu1. In contrast to this, agents inducing mitotic recombination and point mutation cause an increase mainly of red but much less of white colonies on the selective cycloheximide medium, and most of the white resistant colonies do not express centromeric marker leu1 (see Mayer and Goin, 1989). Consequently, chemicals inducing chromosome loss can be readily distinguished from those inducing only mitotic recombination and point mutation.
Therefore, it is important to test white resistant colonies for the expression of centromere marker leu1 in addition to resistance marker cyh2 and color marker ade6. Induction of multiple events of mitotic recombination will lead to white resistant colonies most of which do not express leu1 whereas induction of chromosome loss is indicated when most of the white resistant colonies express this marker.
Diploid strain D7, originally designed by Zimmermann et al. (1975), allows the detection of both types of mitotic recombination: mitotic gene conversion by the generation of a wild-type allele from a heteroallelic pair of trp5-12 and trp5-27 which cause a requirement for tryptophan, and mitotic crossing-over which is unambiguously detected by the appearance of red and pink twin-sectored colonies due to the homozygous conditions of red mutant allele ade2-40 and pink allelc ade2-119. These two alleles show allelic complementation so that the heteroallelic diploid ade2- 40/ade2-110 forms white colonies. In addition to such twin-sectored colonies, there can be homogeneously red or pink and red/white or pink/white colonies which can arise by mitotic gene conversion, point mutation and combinations of mitotic recombination and lethal sectoring. D7 is also homothallic for ilv-92 and thus requires isoleucine for growth, a condition that can be exploited to study the induction of reverse mutation.
The growth media and preparation of cultures have been described in the above publications.

Induction of chromosome loss in yeast by aprotic polar solvents is stronger at lower than the normal growth temperatures of 28 or 30°C. There are two technical ways to improve induction. A cold shock regimen (Zimmermann et al, 1985a) consists of a 4-h incubation period in a growth medium at 28°C, followed by storage in ice for more than 6 h - usually overnight - followed by another 4-h period of incubation at 28 or 30°C. Another regimen consists of a continuous incubation at 20°C for 16-17 h (Zimmermann et al., 1988). Mitotic crossing-over in strain D7 creates twin-sectored pink-red colonies provided there is no cell division between induction and the time of plating. However, treatment of cells for 17 h in a growth-supporting medium will allow cell division to occur and therefore, twin- sectored colonies are rarely observed.

Results and discussion

Test results

Species / strain:

Saccharomyces cerevisiae

Metabolic activation:

not specified

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

not specified

Additional information on results:

Propionitrile is one of the strongest inducers of mitotic chromosome loss and also weakly re- combinogenic in yeast strain D61.M (Zimmer- mann et al., 1988). A dose-response curve for the induction of genetic effects was established for pure MMS and MMS in combination with 14.2 mg/ml propionitrile following the cold shock regimen.
At 20.7 mg/ml, propionitrile induced a high frequency of chromosome loss. About one third of the resistant colonies were white. They were not further tested because many previous experiments had established that most of them express leul. The frequency of red resis- tant colonies remained at the control level. In contrast to this, MMS induced a strong dose-re- lated increase of red resistant colonies whereas only few of the white colonies expressed leul and their frequencies varied erratically. Propionitrile at 15.2 mg/ml induced chromosome loss at a low level with 30 out of 31 colonies expressing leul. It enhanced the frequencies of MMS-induced red resistant colonies up to 4-fold whereas only a minority of the white resistant colonies expressed leul and their incidence was doubled at only one dose point.

Applicant's summary and conclusion

Conclusions:

In the yeast Saccharomyces cerevisiae, proprionitrile was a strong inducer of mitotic chromosome loss and also weakly recombinogenic in yeast strain D61.M.