Fundamental Toxicological Sciences

Bulgarian Journal of Veterinary Medicine, 2019

The mutagenic potential of selected widely used pesticides: p,p'-dichlorodiphenyltrichloroethane (DDT); fenitrothion; propoxur; deltamethrin, bifenthrin; imidacloprid and thiametoxam was assessed using the wing spot test. Third-instar larvae of standard Drosophila melanogaster cross (ST), transheterozygous for the third chromosome recessive markers, multiple wing hairs (mwh) and flare (flr 3) were chronically exposed to test compounds. Feeding ended with pupation of the surviving larvae. Genetic changes induced in somatic cells of the wing's imaginal discs, mutant spots observed in marker-heterozygous (MH) and balancer-heterozygous (BH) flies were compared using the wing spot test, to estimate the genotoxic effects of these pesticides. In conclusion, exposure to 30 mg/mL deltamethrin, 40 mg/mL imidacloprid, 100 µg/mL DDT showed mutagenic and recombinagenic effects in the Drosophila wing spot test. In addition the results of chronic treatments performed at high doses showed mutagenic and recombinagenic effects in both genotypes.

2017

Under the pretext of demographic growth with all its consequences, agricultural production resorts to the use of a varied and a large quantity of insecticides to improve the production and preservation of foodstuffs. Thus, the use of insecticides has increased rapidly and is now widespread to the lowest level of agricultural production. Insecticides are products of chemical or biological origin that control insects (Ware and Whitacre, 2004). They include ovicides and larvicides used against the eggs and larvae of insects respectively and are used in agriculture, medicine, industry and the household. Insecticides are believed to be the major factors behind the increase in agricultural productivity in the 20th century (van Emden and Pealall, 1996). Control insects may result from killing the insect or otherwise preventing it from engaging in behaviors deemed destructive. Insecticides may be natural or manmade and are applied to target pests in a myriad of formulations and delivery systems (sprays, baits, slow-release diffusion, etc.). Biotechnology has, in recent years, even incorporated bacterial genes coding for insecticidal proteins into various crops to kill pests that feed on them (Ware and Whitacre, 2004). Obviously, this abundant and diversified use of insecticides constitutes a danger not only for aquatic and terrestrial biodiversity, but also for humans because of their presence in food chains. The World Health Organization (WHO) estimates at 20,000 the number of deaths caused by pesticides each year worldwide with a substantial proportion due to insecticides (Darren et al., 2003). These incidents are particularly common in developing countries; where the marketing of pesticides do not respect international quality standards. Moreover, many studies conducted all over the world report undeniable links between insecticides and serious health consequences including endocrine disruption and fertility problems (Colborn et al.

Interdisciplinary Toxicology, 2013

The possible genotoxic activity of Dichlorvos (2,2-Dichlorovinyl-O,O-dimethyl phosphate/DDVP, CAS No. 62-73-7), an organophosphorus insecticide was investigated employing three cytogenetic end points, i.e. micronucleus (MN) assay, mitotic indices (MI) and chromosome abberation (CA) analysis in vivo. The assays were carried out in hematopoietic bone marrow cells of Mus musculus at concentrations of 10, 20 and 30% of LD50 for intraperitoneal (ip) administration, corresponding to 0.06, 0.08 and 0.13 mg/kg Bwt, respectively. The normal control group received single ip dose of distilled water (2 ml/100 g Bwt), while animals of the positive group were injected with cyclophosphamide, a model mutagen (40 mg/kg Bwt) under identical conditions. The animals were sacrificed 24, 48 and 72 hrs post treatment. Under the present experimental conditions, there was no evidence of significant increase of MN frequencies at any dose or sampling time in polychromatic (PCE) and normochromatic (NCE) erythr...

Mutation Research/Genetic Toxicology and Environmental Mutagenesis, 2004

In the present study, the herbicides bentazone, molinate, thiobencarb and trifluralin were evaluated for mutagenic and recombinagenic effects using the wing spot test of Drosophila melanogaster (somatic mutation and recombination test, SMART). Both standard (ST) and high-bioactivation (HB) fly crosses were used, the latter cross is characterised by a high sensitivity to promutagens and procarcinogens. Three-day-old larvae, transheterozygous for the multiple wing hairs (mwh, 3-0.3) and flare-3 (flr 3 , 3-38.8) genes, were chronically fed with six different concentrations of each herbicide. Feeding ended with pupation of the surviving larvae and the genetic changes induced in somatic cells of the wing's imaginal discs lead to the formation of mutant clones on the wing blade. Point mutation, chromosome breakage and mitotic recombination produce single spots; while twin spots are produced only by mitotic recombination. Bentazone, usually considered as a non-mutagen, gave positive results in the wing spot test with the high-bioactivation cross. Molinate, about which information on mutagenic effects is inconclusive, gave positive responses in both the standard and the high-bioactivation crosses, while the other thiocarbamate, thiobencarb, gave positive results only in the standard cross and at the highest concentration tested (10 mM). Finally, trifluralin, one of the most widely studied herbicides for genotoxic effects, gave positive results in the wing spot test with both crosses. Apart from the interest of the results found in the genotoxic evaluation of the four selected herbicides, our results also contribute to extend the existing database on the Drosophila wing spot test, and corroborate the utility of the use of high-bioactivation strains for the genotoxic evaluation of xenobiotics.

Mutation Research/Genetic Toxicology, 1992

The herbicides alachlor, atrazine, maleic hydrazide and paraquat were evaluated for genotoxicity in the Drosophila melanogaster wing spot test. Third-instar larvae trans-heterozygous for two recessive mutations of wing trichomes, multiple wing hairs (mwh) and flare (fir3), were treated by chronic feeding with different concentrations of the four herbicides. Feeding ended with pupation of the surviving larvae. The genotoxic effects were determined from the appearance of clones of cells with mwh, fir 3 or mwh-flr 3 phenotypes. Exposure to maleic hydrazide resulted in a significant increase in the frequency of the three categories of spots recorded (small single, large single and twin spots) in a dose-related fashion. Exposure to alachlor induced significant increases in both small and total spots at the four concentrations assayed and in the frequency of twin spots at the highest concentration tested (10 mM). Atrazine and paraquat also induced significant increases in both small and total spots at three of the four concentrations tested, without indication of a direct dose-effect relationship.

Revista Colombiana de Entomología

Drosophila suzukii (Diptera, Drosophilidae) is an exotic species, endemic to Asia and currently a pest to small and stone fruits in several countries of North America and Europe. It was detected in 2013 for the first time in South America, in the south of Brazil. Unlike most drosophilids, this species deserves special attention, because the females are capable of oviposit inside healthy fruits, rendering their sale and export prohibited. Despite the confirmed existence of this species in different states of Brazil, this insect is yet been to be given the pest status. Nevertheless, the mere presence of this species is enough to cause concern to producers of small fruits and to justify further investigation for it’s control, especially chemical control for a possible change in status. Therefore, the goal of this work was to evaluate, in laboratory, mortality of D. suzukii adults and ovicidal effect when exposed to different insecticides registered for species of the Tephritidae and Ag...

Environmental and Molecular Mutagenesis, 2000

Four herbicides, namely propanil, maleic hydrazide, glyphosate, and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), were investigated for genotoxicity in the wing spot test of Drosophila melanogaster. The herbicides were administered by chronic feeding to 3-dayold larvae. Two different crosses, a standard (ST) and a high-bioactivation (HB) cross, involving the flare-3 (flr 3 ) and the multiple wing hairs (mwh) markers, were used. The HB cross uses flies characterized by an increased cytochrome P-450 -dependent bioactivation capacity, which permits a more efficient biotrans-formation of promutagens and procarcinogens. In both crosses, the wings of the two types of progeny, which are inversion-free marker heterozygotes and balancer heterozygotes, were analyzed. Maleic hydrazide and glyphosate proved to be more genotoxic in the ST cross, whereas propanil appeared to be slightly more genotoxic in the HB cross. On the other hand, the herbicide 2,4,5-T increased the mutation frequency for only the small single spots in the ST cross. Environ. Mol. Mutagen. 36:40 -46, 2000.

Cell Biology and Toxicology, 2005

This study investigated the working hypothesis that two widely used organophosphate pesticides; Nuvan and Dimecron, exert toxic effects in Drosophila. was used as a model for assaying stress gene expression and AchE activity as an endpoint for toxicity and also to evaluate whether stress gene expression is sufficient to protect against toxic insult of the chemicals and to prevent tissue damage. The study was extended to investigate the effect of the pesticides on the life cycle and reproduction of the organism. The study showed that Nuvan affected emergence of the exposed flies more drastically than Dimecron and the effect was lethal at the highest tested concentration (0.075 ppm). While Nuvan at 0.0075 and 0.015 ppm concentrations affected reproduction of the flies significantly, the effect of Dimecron was significant only at 0.015 and 0.075 ppm. Nuvan-exposed third-instar larvae exhibited a 1.2-fold to 1.5-fold greater hsp70 expression compared to Dimecron at concentrations ranging from 0.0075 to 0.075 ppm following 12 and 18 h exposure. While maximum expression of hsp70 was observed in Nuvan-exposed third-instar larval tissues following 18 h exposure at 0.075 ppm, Dimecron at the same dietary concentration induced a maximum expression of hsp70 following 24 h exposure. Further, concomitant with a significant induction of hsp70, significant inhibition of AchE was observed following chemical exposure and temperature shock. Concurrent with a significant decline in hsp70 expression in Nuvan-exposed larvae after 48 h at 0.075 ppm, tissue damage was evident. Dimecron-exposed larvae exhibited a plateau in hsp70 induction even after 48 h exposure and moderate tissue damage was observed in these larvae. The present study suggests that Nuvan is more cytotoxic than Dimecron in transgenic Drosophila melanogaster.