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The in vivo model Drosophila melanogaster was used here to determine the detrimental effects induced by silver nanoparticles (AgNPs) exposure. The main aim was to explore its interaction with the intestinal barrier and the genotoxic effects induced in hemocytes. The observed effects were compared with those obtained by silver nitrate, as an agent acting via the release of silver ions. Larvae were fed in food media containing both forms of silver. Results indicated that silver nitrate was more toxic than AgNPs when the viability "egg‐to‐adult" was determined. Depigmentation was observed in adults including those exposed to nontoxic concentrations, as indicative of exposure action. Interestingly, AgNPs were able to cross the intestinal barrier affecting hemocytes that show significant increases in the levels of intracellular reactive oxygen species. Additionally, significant levels of genotoxic damage, as determined by the comet assay, were also induced. When the expression of different stress‐response genes was determined, for both AgNPs and silver nitrate, significant upregulation of Sod2 and p53 genes was observed. Our results confirm for the first time that in an in vivo model as Drosophila, AgNPs are able to cross the intestinal barriers and produce primary DNA damage (comet assay) via oxidative stress induction. In general, the effects induced by silver nitrate were more pronounced than those induced by AgNPs what would emphasize the role of silver ions in the observed effects. Environ. Mol. Mutagen. 60:277–285, 2019. © 2018 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Since most of the toxic studies of zinc oxide nanoparticles (ZnO NPs) focused on acute and high-dose exposure conditions, the aim of the present study was to fill the existing knowledge gap of long-term effects of ZnO NPs at sub-toxic doses. To overcome this point, we have evaluated the toxic, genotoxic, and carcinogenic effects of ZnO NPs under long-term treatments (12 weeks), using a sub-toxic dose (1 µg/mL) according to acute 48-h exposure. Preliminarily, oxidative stress and genotoxic/oxidative DNA damage were determined under acute exposure and high-dose conditions. To determine the role of oxidative DNA damage, a wild- type mouse embryonic fibroblast (MEF Ogg1 ) and its isogenic 8-oxo-guanine DNA glycosylase 1 ( Ogg1) knockout partner (MEF Ogg1 ) cell lines were used. Although short-term exposure (24-h) experiments demonstrated that ZnO NPs were able to induce ROS, genotoxicity, and oxidative DNA damage in both cell lines, no effects were obtained under long-term exposure scenario. Thus, 1 µg/mL exposure over 12 weeks was unable to induce genotoxicity as well as cellular transformation in both cell types, as indicated by the lack of observed morphological cell changes, variations in the secretion of matrix metalloproteinases, and anchorage-independent cell growth ability, regarded as cancer-like phenotypic hallmarks. Our results indicate that short-term effects of ZnO NP exposure are not replicated under long-term and sub-toxic dose conditions. All together, the lack of genotoxic/carcinogenic effects after chronic treatments seem to indicate a reduced risk associated with ZnO NP exposure. [ABSTRACT FROM AUTHOR]

Metal oxide nanoparticles are highly reactive from the biological point of view and, for this reason, it exists important reservations in regard human health impact. We usedDrosophilaas a promisingin vivomodel to diagnose the biological effects of copper oxide nanoparticles (CuO-NPs). Due to the potential role of ions release the effects of CuO-NPs were compared with those induced by copper sulfate, CuSO4. A wide battery of approaches has been used including toxicity, cell and body internalization, induction of reactive oxygen species (ROS) as well as changes in gene expression, related to both general stress and alterations in the intestinal barrier, and genotoxicity. The obtained results show that CuO-NPs have the ability to be distributed inside midgut cells and translocate to the general body compartment (internal hemolymph) interacting with hemocytes. Its exposure leads to reduced larval growth, decreased flies viability, delaying their emergency periods, especially at higher doses (2 and 10 mM). Moreover, deregulation of stress genes including antioxidant genes, and genes involved in wound healing were also observed. In this point it should be emphasized the novelty of using genes such asDuox, Upd3, PPO2, andHmlto determine injury on the intestinal barrier. On the other hand, CuO-NPs had non-genotoxic potential, in agreement with their inability to increase ROS production. In general dissolved copper produced higher toxic/genotoxic effects than those induced by CuO-NPs which would indicate that copper ions alone are more important in inducing harmful effects than copper nanoparticles itself. [ABSTRACT FROM AUTHOR]

Althoughin vitroapproaches are the most used for testing the potential harmful effects of nanomaterials,in vivostudies produce relevant information complementingin vitrodata. In this context, we promote the use ofDrosophila melanogasteras a suitablein vivomodel to characterise the potential risks associated to nanomaterials exposure. The main aim of this study was to evaluate different biological effects associated to cerium oxide nanoparticles (Ce-NPs) and cerium (IV) sulphate exposure. The end-points evaluated were egg-to-adult viability, particles uptake through the intestinal barrier, gene expression and intracellular reactive oxygen species (ROS) production by haemocytes, genotoxicity and antigenotoxicity. Transmission electron microscopy images showed internalisation of Ce-NPs by the intestinal barrier and haemocytes, and significant expression ofHspgenes was detected. In spite of these findings, neither toxicity nor genotoxicity related to both forms of cerium were observed. Interestingly, Ce-NPs significantly reduced the genotoxic effect of potassium dichromate and the intracellular ROS production. No morphological malformations were detected after larvae treatment. This study highlights the importance ofD. melanogasteras animal model in the study of the different biological effects caused by nanoparticulated materials, at the time that shows its usefulness to study the role of the intestinal barrier in the transposition of nanomaterials entering via ingestion. [ABSTRACT FROM PUBLISHER]

The elongated nature of the high-aspect-ratio nanomaterials (NMs) can help us to obtain valuable information on its biodegradation, physical interaction with target-cells, and internalization. Three different length nano-titanium have been studied using Drosophila, TEM, and different biological markers. Nano-titanium, regardless of its shape, was eroded and degraded just entering the gut lumen of the larvae. Results showed that the distinguished shape of nanowires helps to understand the interactions of NMs with the intestinal barrier. The peritrophic membrane, as the first defense line of the intestinal barrier, succeeded in the reservation of NMs, though the perpendicular particles of nanowires stabbing it, making pores, and permitting their translocation into intestinal cells. On the other side, the exposure to TiO 2 NPs did not decrease egg-to-adult viability, but all its different shapes, especially nanowires, mediated a wide molecular response including changes of expression in genes involved in stress, antioxidant, repair, and physical interaction responses. All these changes concerning their ability to elevate ROS levels ultimately led to potential genotoxicity. So, the high aspect ratio NMs are efficient in understanding the outstanding issues of NMs exposure, but at the same time could induce genotoxic impact rather than the low aspect ones. ga1 • Three different shapes of titanium nanomaterials (nanowires, nanorods, nanospheres) were evaluated in Drosophila. • The journey of the TiNMs through the larvae midgut was carefully followed, step by step, using TEM. • TiNMs can be eroded and degraded in the midgut as a result of their interaction with biotic and abiotic factors. • Effects such as oxidative stress and genotoxicity are length-dependent. [ABSTRACT FROM AUTHOR]