Genotoxicity of Rogor studied in the sex-linked recessive lethal test and wing, eye and female germ-line mosaic assays in Drosophila melanogaster

The genotoxic potential of Rogor (dimethoate), an anticholinesterase organophosphate insecticide, has been studied in the sex-linked recessive lethal test and the wing, eye and female germ-line mosaic assays in Drosophila melanogaster. Larvae of different instars carrying suitable recessive genetic markers on their first and third chromosomes were exposed to the LD50 or half of this dose for the entire larval life. The Basc technique was followed for the detection of the induction of sex-linked recessive lethals. The wings and eyes of the adult flies and the eggs laid by the heterozygous females were checked for the induction of mosaicism. It is concluded that Rogor induces sex-linked recessive lethals in immature male germ cells and is recombinogenic and/or mutagenic in both the somatic and the germ-line cells of Drosophila.     

Genotoxicity of zineb detected through the somatic and germ-line mosaic assays and the sex-linked recessive-lethal test in Drosophila melanogaster

The genotoxicity of zineb, a carbamate fungicide, has been tested through eye, wing and female germ line mosaic assays and the sex-linked recessive-lethal test in Drosophila melanogaster. Larvae of different instars, heterozygous for appropriate recessive genetic markers, were exposed to the fungicide in food for different durations of time. The adult eyes and wings were screened for induction of mosaic spots and the eggs laid by the females were checked for induction of female germ-line mosaicism. It is concluded that zineb is genotoxic to both somatic and germ-line cells of Drosophila.     

Mutagenicity of dimecron studied in 3 mosaic assays and the sex-linked recessive lethal test in Drosophila melanogaster

The genotoxicity of dimecron, a systemic organophosphate pesticide, has been tested in the wing, eye and germ line mosaic assays and the sex-linked recessive lethal test in Drosophila melanogaster. Larvae heterozygous for recessive marker mutations were fed the compound for various periods of time. On emergence, the wings and eyes of the adults were screened for mosaic spots and the eggs laid by the females were checked for induction of female germ line mosaicism. Dimecron is mutagenic to the somatic and germ line cells of Drosophila and induces a high frequency of sex-linked recessive lethals.     

Acrylamide is genotoxic to the somatic and germ cells of Drosophila melanogaster

The genotoxic effects of acrylamide, a recently detected carcinogen, have been studied in the somatic (wing primordia) and germ cells of Drosophila melanogaster by the wing mosaic assay and the sex-linked recessive lethal test respectively. Larvae, 72 +/- 4 h old, were exposed to 6 different concentrations of acrylamide ranging between 0.25 mM and 5.0 mM in instant medium for 48 h. It is observed that acrylamide is both mutagenic and recombinogenic in the wing disc cells and induces sex-linked recessive lethals.     

Testing the mutagenicity of malondialdehyde and formaldehyde by the Drosophila mosaic and the sex-linked recessive lethal tests

The mutagenicities of malondialdehyde and formaldehyde were tested by screening each for genetic mosaics of Drosophila melanogaster and by the Muller-5 test for sex-linked recessive lethal mutations. For comparison, the effects of X-rays were also assayed by the above technique. Malondialdehyde, a degradation product of polyunsaturated fatty acids, was found to be a weak mutagen by the above criteria; it induced point mutations and chromosome exchanges at low frequency, as proved by the mosaic test, but failed to induce detectable sex-linked lethality. Formaldehyde was more mutagenic than malondialdehyde; beside induction of mosaic spots it induced sex-linked recessive lethal mutations, but only in the larval testes of Drosophila. Formaldehyde also induced disintegration of the clones. Formaldehyde treatment (feeding larvae with formaldehyde-containing food for about 4 days) was 5 times more mutagenic than malondialdehyde treatment and 5 times less effective than irradiation by 1000 R of X-rays. Wing mosaicism offers a more sensitive way to detect mutagenesis as compared with eye mosaicism. It is suggested that aldehyde-induced mosaic spots derive from mitotic recombination and point mutations.     

Farm-grade chlorpyrifos (Durmet) is genotoxic in somatic and germ-line cells of Drosophila.

The mutagenic potential of Durmet, a farm-grade formulation of chlorpyrifos, was studied in the Drosophila wing mosaic and sex-linked recessive lethal tests. Larvae of the 2nd or 3rd instar carrying suitable recessive genetic markers on chromosome 3 were exposed to different concentrations of the insecticide and the frequency of induction of mutant mosaic spots on the wings was noted. The Basc technique was followed to study the induction of sex-linked recessive lethals. On the basis of the frequency of induction of mosaic wing spots and sex-linked recessive lethals, it is concluded that Durmet is genotoxic in somatic cells as well as germ cells of Drosophila.     

A Study of Spontaneous Mutation Rates at Ten Loci Detectable by Starch Gel Electrophoresis in DROSOPHILA MELANOGASTER

Spontaneous mutation rates at ten allozyme loci on chromosomes II and III of Drosophila melanogaster were studied. Over the three and a half years study, one alpha-GPD mutation and two different IDH mutations were obtained. The alpha-GPD mutation was inherited in the Mendelian fashion, as expected. The two IDH mutations were peculiar in that the band of new types appeared only in females. In males, only the original bands were stained, and the positions where mutant alleles' bands should be present were blank. Both IDH mutant homozygotes appeared as null allele homozygotes, while in females clear-cut single bands were present.-The rates of spontaneous mutation varied greatly. Eight loci studied (MDH, ADH, EST-6, APH, EST-C, ODH, XDH, AO) did not give any germ-line mutation. The average germ-line mutation rate over all ten loci was estimated at 4.5 x 10(-6). This rate is considerably smaller than that for sex-linked recessive visible mutations (Muller, Valencia and Valencia 1950), but it is somewhat less than autosomal recessive visible mutations (Glass and Ritterhoff 1956).     

The influence of electrostatic and magnetic fields on mutation in Drosophila melanogaster spermatozoa.

Canton-S Drosophila melanogaster males were exposed to electrostatic and magnetic fields for 24 h to determine the influence of low energy fields on the production of sex-linked recessive lethal mutations in the mature, motile sperm. To detect sex-linked recessive lethal production in mature sperm the standard Muller-5 test was done. Exposure of the males to the magnetic field or the electrostatic field did not significantly affect the mutation frequency in mature sperm.     

Testing of chloroquine and quinacrine for mutagenicity in Drosophila melanogaster

To extend the data on the mutagenic effects of intercalating agents in Drosophila melanogaster, chloroquine and quinacrine were tested for the induction of genetic damage in D. melanogaster males. Sex-linked recessive lethals and sex-chromosome loss induction were studied following treatment of adult males using a feeding technique. Our results show that both intercalating compounds increase significantly the frequency of sex-linked recessive lethals, but are unable to induce sex-chromosome loss in male germ cells under the conditions of testing.     

Production of mosaic lethals in different germ cell stages of drosophila by N-methyl-N'-nitro-N-nitrosoguanidine.

The delayed effect of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was studied in Drosophila melanogaster by the proportion of mosaic progeny produced after this treatment. Following injection of the chemical into wild type males, complete and mosaic sex-linked recessive lethals were scored by the Muller-5 method, in five successive broods representing the different stages of spermatogenesis. All broods showed significant increase over the control in the frequencies of complete lethals with gradual decrease in mutation rate from the post-meiotic stages to the pre-meiotic ones. In the case of mosaic lethals, too, the post-meiotic stages were generally more sensitive; but the increase over the control was significant only for the mature spermatozoa. The extension of the experiment to F4 generation showed that a mosaic F1 female may produce further mosaic progeny. The production of lethal mutations in successive generations after treatment with MNNG supports the view that chemically induced instabilities can be transmitted as such over several generations.     

Mutagenicity studies in Drosophila melanogaster with Lannate 20

Lannate 20 a carbamate pesticide was evaluated for its mutagenicity in Drosophila melanogaster by the sex-linked recessive lethals and chromosome II-III translocation tests by continuous larval feeding. The 3 sublethal doses of 0.2, 0.4 and 0.6 microliter of Lannate per 100 ml of the food medium induced a significant (P less than 0.01) increase in the number of sex-linked recessive lethals over the controls. However, no translocations were observed either in the treated or the control series.     

Absence of mutagenicity of the antitumor drug 3-nitrobenzothiazolo[3,2-a]quinolinium chloride (NBQ) in the germ cells of Drosophila melanogaster males.

The antitumor drug, 3-nitrobenzothiazolo[3,2-a]quinolinium chloride (NBQ) was tested for genotoxicity with the sex-linked recessive lethal test by feeding Drosophila melanogaster males. Although toxic to adults, the drug tested negative at the concentrations studied.     

The spontaneous mutation rate in Drosophila simulans

The purpose of this investigation was to determine whether there exists a correlation in Drosophila between the spontaneous mutation rate and the amount of dispersed middle repetitive (mobile) DNA sequences. The amount of these sequences is 7 times less in Drosophila simulans as compared to Drosophila melanogaster. Therefore, if a correlation exists, the spontaneous mutation rate in Drosophila simulans should be 7 times lower than that in Drosophila melanogaster. We isolated an X-chromosome inversion after X-irradiation of wild-type Drosophila simulans males, that reduced crossing-over between white and forked, two X-linked visible markers, to less than 1%. This inversion was subsequently used to determine the sex-linked recessive lethal mutation rate in Drosophila simulans males of a laboratory strain marked with white. The frequency of these lethal mutations found is not different from that observed in Drosophila melanogaster males of laboratory strains.     

Study of genotoxicity and antigenotoxicity of the Cotinus coggygria Scop. methanol extract by Drosophila melanogaster sex-linked recessive lethal test

The genotoxic and antigenotoxic effects of Cotinus coggygria Scop. methanol extract was investigated using the Drosophila sex-linked recessive lethal (or SLRL) test. The results presented here show that the methanol extract of Cotinus coggygria in a concentration of 5% and artificial chemical agent ethyl methanesulfonate EMS (0.75 ppm) induce recessive lethal mutations on X-chromosome on Drosophila melanogaster in all broods (I, II and III). Post-treatment with lower concentration of the methanol extract of Cotinus coggygria (2%) was effective in reducing genotoxicity ofmutagen.     

Germinal and somatic mutation induction in Drosophila after treatment of larvae with tritiated water.

The present study was carried out to evaluate the mutagenicity of tritium, administered as tritiated water, in Drosophila melanogaster. Larvae were fed on tritium-treated medium during their development. Germinal and somatic mutation induction was detected by means of the sex-linked recessive lethal and the wing spot tests, respectively. Our results show that beta-radiation from tritium is able to induce significant increases in the frequency of both germinal and somatic mutations.     

Evaluation of mutagenic effect of the fungicide fenaminosulf in Drosophila melanogaster

Fenaminosulf (p-dimethylaminobenzenediazo sodium sulfonate, CAS registry No. 140-56-7) which is an active ingredient in several commercial fungicides was reported to be mutagenic in Salmonella typhimurium (McCann et al., 1975), Bacillus subtilis (Kada et al., 1974) and shown to cause chromosome aberrations in plants (Zutshi and Kaul, 1975). Since fenaminosulf has structural similarity to the potent carcinogen, butter yellow (p-dimethylaminoazobenzene, CAS registry No. 60-11-7), the present studies were undertaken to evaluate the mutagenic potential of this fungicide in Drosophila melanogaster. Fenaminosulf administered at 10 mg/100 ml food medium failed to induce sex-linked recessive mutations in Drosophila. Since Drosophila has drug-metabolizing enzymes similar to those of mammals (Vogel, 1975), it is suggested that the lack of mutagenic activity of fenaminosulf could be due to the conversion of fenaminosulf to non-mutagenic derivatives in Drosophila.     

Mutagenicity of four hair dyes in Drosophila melanogaster.

The hair dye constituents p-phenylenediamine, 2,4-diaminoanisole sulfate, 2,4-diaminotoluene and 4-nitro-0-phenylenediamine were tested for mutagenicity in Drosophila melanogaster. The compounds were given orally to adult males. The induction of sex-linked recessive lethal mutation was used as a measure of mutagenicity. All four of the dyes tested were mutagenic with a peak mutagenic activity in metabolically active germ cells (spermatids and spermatocytes).     

The lack of ability of carcinogens and non-carcinogenic analogs to induce sex-linked recessive lethals in Drosophila melanogaster

The mutagenic activity of two known carcinogens (benzo(a) pyrene and 2-acetylaminofluorene) and that of two structurally closely related but not carcinogenic compounds (pyrene and 4-acetylaminofluorene) was examined by the Muller-5 test for sex-linked recessive lethals (SRL). The chemicals tested were applied to the food medium for larvae of Canton-S Drosophila melanogaster. No statistically significant differences in frequencies of induced SRL were found either within pairs of chemicals or between treated and untreated animals.     

The mutational spectrum of procarbazine in Drosophila melanogaster.

The antineoplastic agent Procarbazine was tested for the induction of genetic damage in Drosophila melanogaster. The compound was administered to adult males by oral application. The following types of genetic damage were measured: (1) sex-linked recessive lethals; (2) dominant lethals; (3) total and partial sex-chromosome loss; and (4) translocations. Procarbazine is highly mutagenic in causing recessive lethal mutations in all stages of spermatogenesis. In sperm a clear-cut concentration-effect relationship is not apparent, but in spermatids such a relationship is obtained for mutation induction at low levels of procarbazine exposure, while at high concentrations the induction of recessive lethals is not a function of concentration. A low induction of total sex-chromosome loss (X,Y) and dominant lethals was observed in metabolically active germ cells (spermatids), but procarbazine failed to produce well-defined breakage events, such as partial sex-chromosome loss (YL,YS) and II-III translocations. The results obtained in Drosophila melanogaster are discussed and compared with the mutational pattern reported in the mouse after procarbazine treatment.     

Mutagenic potential of permethrin in the Drosophila melanogaster (Diptera: Drosophilidae) sex-linked recessive lethal test

When permethrin was tested for mutagenicity in Drosophila melanogaster Meigen with the sex-linked recessive lethal test, it was nonmutagenic under conditions of this study. The frequencies of spontaneous mutation for permethrin and the negative control were 0.135% and 0.133%, respectively; the spontaneous mutation frequency for positive control was 12.6%. The difference between the mutation frequency of permethrin and the negative control was not significant.