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Mutagenicity of DNOC in Drosophila melanogaster
Abstract:
The insecticide/ascaricide dinitro-ortho-cresol (DNOC) was tested for mutagenicity in BASC or Muller-5 test with Drosophila melanogaster. The frequencies of induced sexlinked recessive lethals in premeiotic and postmeiotic germ cell stages of spermatogenesis were determined after exposure of adult wild-type males by oral application of DNOC. Sex-linked recessive lethals were scored in the F2 generation according to standard procedures. The mutagenic activity of DNOC at concentrations of 0.25 to 1.01 mM (50-200 ppm) in postmeiotic germ cell stages (11 lethals/1570 chromosomes tested = 0.70%) > premeiotic stages (3/1001 = 0.29%). The mutations rate in all germ cell stages was 0.59% (18/3140). The lowest effective concentration for the induction of recessive lethals in nature sperm was 0.25 mM which is 1/3 to 1/2 LD50 which is approximately 0.61 mM. The frequency of spontaneously occurring lethality was 0.06 (1/1718). The data presented here show significant differences in Kastenbaum-Bowman test. Dimethylnitrosamine (6.8 mM = 500 ppm) induced a rate of 21.0% of lethals (112/534).
Insights
Dinitro-ortho-cresol (DNOC), an insecticide, showed mutagenic activity in Drosophila melanogaster, inducing sex-linked recessive lethals. Higher mutation rates were observed in postmeiotic germ cells compared to premeiotic stages.
Area of Science:
- Toxicology
- Genetics
- Entomology
Background:
- Dinitro-ortho-cresol (DNOC) is a widely used insecticide and ascaricide.
- Assessing the mutagenicity of pesticides is crucial for environmental and human health risk evaluation.
- Drosophila melanogaster serves as a model organism for genotoxicity testing.
Purpose of the Study:
- To evaluate the mutagenic potential of DNOC in Drosophila melanogaster.
- To determine the sensitivity of different germ cell stages to DNOC-induced mutations.
- To establish the lowest effective concentration of DNOC for inducing genetic damage.
Main Methods:
- The study utilized the BASC or Muller-5 test in Drosophila melanogaster.
- Adult wild-type male flies were exposed to varying concentrations of DNOC via oral application.
- Sex-linked recessive lethals were quantified in the F2 generation.
Main Results:
- DNOC induced sex-linked recessive lethals in both premeiotic and postmeiotic germ cell stages.
- Mutagenic activity was higher in postmeiotic stages (0.70%) than in premeiotic stages (0.29%).
- The lowest effective DNOC concentration for inducing lethals in mature sperm was 0.25 mM, approximately 1/3 to 1/2 of the LD50.
Conclusions:
- DNOC exhibits significant mutagenic activity in Drosophila melanogaster.
- Germ cell stage sensitivity to DNOC mutagenicity varies, with postmeiotic stages being more susceptible.
- The findings highlight the genotoxic risk associated with DNOC exposure.