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The aim of this study is to evaluate the ameliorative effect of melatonin (MEL) against induced genotoxicity by cobalt (II) chloride (CoCl2) and cobalt nanoparticles (CoNPs) (50 nm). Genotoxicity of CoCl2 and CoNPs were investigated using single cell gel electrophoresis (COMET) in Drosophila melanogaster hemocytes, which are blood cells of the Drosophila, and the somatic mutation and recombination test (SMART) was used to investigate mutant effects on the Drosophila wings. Three concentrations (0.1, 1, and 10 mM) of CoNPs and CoCl2 were applied to demonstrate their genotoxic potential. Both CoNPs and CoCl2 have mutagenic potential for the three concentrations tested in the COMET assay; however, only the 10 mM concentration of the ionic form and two high concentrations (1 and 10 mM) of CoNPs induced genotoxicity in the Drosophila SMART assay. Three different concentrations of MEL (0.1, 0.5 and 2.5 mM) were used against cobalt at highest concentration (10 mM) of both CoCl2 and CoNPs in both the SMART and COMET assays. MEL ameliorated the genotoxicity induced by CoCl2 and CoNPs in vivo Drosophila COMET and SMART assays. [ABSTRACT FROM AUTHOR]

Nanogenotoxicology is an emergent area of research, relevant for estimating the potential carcinogenic risk of nanomaterials. Since most of the approaches use in vitro studies, and neglecting the whole organism limits the accuracy of the obtained results, we have used Drosophila melanogaster to study the possible genotoxic potential of cobalt nanoparticles (Co NPs). The wing somatic mutation and recombination test has been the test of choice. This test is based on the principle that the loss of heterozygosis and the corresponding expression of the suitable recessive markers, multiple wing hairs and flare-3 can lead to the formation of mutant clone cells in growing up larvae, which are expressed as mutant spots on the wings of adult flies. Co NPs, as well as the ionic form cobalt chloride, were given to third instar larvae through the food, at concentrations ranging from 0.1 to 10 mM. The results obtained indicate that both cobalt forms are able to induce significant increases in the frequency of mutant clones. Although at low concentrations only Co NPs were genotoxic, the level of genetic damage obtained at the highest dose tested of cobalt chloride (10 mM) showed a significant higher increase in the frequency of total spots than those observed after the treatment with cobalt nanoparticles. As conclusion, our results indicate that Co NPs were able to induce genotoxic activity in the wing-spot assay of D. melanogaster, mainly via the induction of somatic recombination. The differences observed in the behaviour of the two selected cobalt forms may result from differences in the uptake. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to assess the adaptive response induced by low doses of ultraviolet-B (UVB, 290-320 nm) radiation in the Drosophila wing spot test. Materials and methods: The adaptive response of Drosophila larvae to UVB light was studied by using a somatic mutation and recombination test (SMART). The SMART system used was the wing spot test, which uses morphological markers of the wing blade. This in vivo test has shown to be very useful to study the induction of genetic damage in somatic cells, measuring loss of heterozygosity (LOH) resulting from gene mutation, mitotic recombination, chromosomal rearrangements or chromosome loss. Results: To determine the induction of adaptive response, two-day-old Drosophila larvae were first irritated with an adaptive dose (58.3 J/m2), followed by different challenge doses (178, 224, 288, 338, and 386 J/m2). When the results obtained in the different challenge doses were compared with those obtained following the application of adaptive plus challenge doses, significant decreases (74.7-80.8%) in a first experiment, and (65.6-78.4%) in a second experiment, were observed in the frequency of mutant spots on the wing blades. Conclusions: Our results show that in Drosophila the adaptive response can be stimulated in vivo by UVB exposure. [ABSTRACT FROM AUTHOR]

Highlights: [•] Drosophila was used to determine the genotoxic risk of several nanomaterials. [•] Titanium, zirconium and aluminium nanoparticles, and their ions were tested. [•] Mutation/recombination effects in wing somatic cells were determined. [•] No increases in genetic damage levels were observed in any treatment. [•] Our results contribute to increase the genotoxicity database on nanomaterials. [ABSTRACT FROM AUTHOR]