Silver nanoparticles (AgNPs) are used intensively in medical and industrial applications. Environmental concerns have arisen from the potential release of this material into aquatic ecosystems. The aims of this research were to evaluate the potential accumulation of silver in the whole body of organisms and analyze the effects of AgNPs on the survival and reproduction of the snail Biomphalaria glabrata. Results show slow acute toxicity with a 10-day LC₅₀ of 18.57 mg/L and an effective decrease in the eggs and egg clutches per organism exposed to tested concentrations. Based on these data, the No Observed Effect Concentration (NOEC) observed was <1 mg/L for snail reproduction. For silver accumulation, we observed that uptake was faster than elimination, which was very slow and still incomplete 35 days after the end of the experiment. However, the observed accumulation was not connected with a concentration/response relationship, since the amount of silver was not equivalent to a higher reproductive effect. The data observed show that AgNPs are toxic to B. glabrata, and suggest that the snail has internal mechanisms to combat the presence of Ag in its body, ensuring survival and reduced reproduction and showing that the species seems to be a potential indicator for Ag presence in contaminated aquatic ecosystems.

Microplastics in freshwater environments pose a serious threat to living beings. Polyethylene microplastics (PE-MP) are the type most used around the world as microbeads in personal care products, and they have been found in aquatic organisms. The behavior and toxicity of fluorescent PE-MP spheres with an average diameter of 58.9 μm were studied in adult, juvenile and embryo zebrafish (Danio rerio). The adults were studied for genotoxicity, cytotoxicity, histology and biochemical markers. Juveniles underwent a follow-up in the gastrointestinal (GI) tract with histologic observations, and embryos were studied for embryotoxicity with the FET-test. In adults, micronucleus test and comet assays found neither genotoxicity after acute exposure for 96 h at concentrations of 0.0, 12.5, 50 and 100 mg.L⁻¹, nor cytotoxicity through the nuclear abnormalities test. Acetylcholinesterase (AChE), Glutathione-S-Transferase (GST) and Lactate Dehydrogenase (LDH) activities were measured in adults exposed for 96 h. The AChE and GST activities were significantly changed, while no changes occurred for LDH. In conclusion, these PE-MP spheres did not cause serious toxic effects in zebrafish because there was no internalization. The observed biochemical changes in AChE and GST may be associated with GI microbiological dysbiosis, previously reported. The PE-MP spheres in the intestine of juveniles remained present for 12–15 days on average after the post-exposure clearance study, showing a slow depuration. The histological analysis, in adults, found no internalization of these microbeads, with complete depuration. The PE-MP spheres did not cross the chorion barrier, showing no embryotoxic effects after exposures at 0.0, 6.25, 12.5, 50.0 or 100.0 mg.L⁻¹ for 96 h.

Doxorubicin (DOX) is an anthracycline antibiotic used in the fight against many types of cancer. Although it is quite effective for this purpose, its clinical use is limited by its severe side effects, highlighting the relevance of efforts to identify substances that act to minimize these effects. In this work, we sought to verify the ability of andiroba oil (AO) and a nanoemulsion of andiroba oil (AN) to lessen the side effects of DOX. The animals were separated into 7 groups with 6 animals each: mice treated with AO (2000 mg/kg), AN (2000 mg/kg), the antineoplastic agent DOX (40 mg/kg), AO+DOX, AN+DOX and solvent controls was used of negative control (corn oil and nanoemulsion surfactant). AO and AN were administered for 14 consecutive days orally by gavage and on the 13th day, applied DOX by intraperitoneal route (i.p.), in order to evaluate the protective potential of andiroba. The animals were euthanized on the 15th day. Hematological, biochemical, histological, and immunohistochemical parameters were analyzed. Andiroba reduced several aspects of the severity of lesions caused by DOX, decreasing hematotoxicity and the severity of histological changes in the liver and kidneys, and reducing the frequency of apoptotic cell death. In many cases, AN showed greater efficacy than AO alone, reflecting the feasibility of using this nanotechnology to improve the pharmacokinetics of lipid compounds in the body. The study sheds new light on the therapeutic benefits of andiroba and suggests new ways for investigating how the quantity and quality of lipid compounds affect exposed organisms.

Bioinsecticides from Bacillus thuringiensis (Bt) are widely used around the world in biological control against larval stages of many insect species. Bt has been considered a biopesticide that is highly specific to different orders of insects, non-polluting and harmless to humans and other vertebrates, thus becoming a viable alternative for combating agricultural pests and insect vectors of diseases. The family of Bt δ-endotoxins are crystal-protein inclusions showing toxicity to insects’ midgut, causing cell lysis leading to starvation, septicemia and death. The aim of this study is to evaluate the genotoxic potential of recombinant Bt spore–crystals expressing Cry1Ia, Cry10Aa and Cry1Ba6 on peripheral erythrocyte cells of Oreochromis niloticus, through comet assay, micronucleus (MN) test and nuclear abnormalities (NA) analysis. Fish (n = 10/group) were exposed for 96 h at 10⁷ spores 30 l⁻¹, 10⁸ spores 30 l⁻¹ or 10⁹ spores 30 l⁻¹ of Bt spore–crystals. Cry1Ia showed a significant increase in comet cells at levels 1 and 2, but not at levels 3 and 4, so it was not mutagenic nor did it induce MN or NA. These three spore–crystals showed some fish toxicity at only the highest exposure level, which normally does not occur in the field.

The threats posed by insecticide resistance to Aedes aegypti in the context of controlling dengue have led to an urgent search for an environmentally safer alternative chemical with more effective larvicidal properties. Among many molecules tested, 2-methylanthraquinone showed the lowest LC50 for A. aegypti in a previous study and the highest LC50 for zebrafish embryos. Embryos were exposed at concentrations of 1.0, 2.19, 4.78, 10.46, 22.87, 50.0 and 100.0 mg/L, and malformations and mortality were significantly observed only at the highest exposures of 50 and 100 mg/L after 96 h. Micronucleus test and comet assay in zebrafish adults were both negative after exposures at 6.25, 12.5, 25.0, 50.0 and 100.0 mg/L for 96 h. Several biochemical biomarkers were analyzed in adults, and 2-methylanthraquinone did not interfere with acetylcholinesterase activity. The lactate dehydrogenase activity was higher at concentrations of 25 and 100 mg/L. Glutathione-S-Transferase (GST) activities were tested in the gill and body (muscle tail). The gill was more sensitive than body for GST activity after exposure to 2-methylanthraquinone, showing the highest activities, and 2-methylanthraquinone showed low toxicity to a non-target organism.