Genotoxic and mutagenic assessment of iron oxide (maghemite-γ-Fe2O3) nanoparticle in the guppy Poecilia reticulata

Magnetic iron oxide nanoparticles: An emerging threat for the environment and human health

Magnetic iron oxide nanoparticles (FexOy NPs, mainly Fe3O4 and γ-Fe2O3) are nanomaterials ubiquitously present in aquatic, terrestrial, and atmospheric environments, with a high prevalence and complex sources. Over the past decade, numerous reports have emerged on the presence of exogenous particles in human body, facilitated by the rapid development of separation and detection methods. The health risk associated with magnetic FexOy NP have garnered escalating attention due to their presence in human blood and brain tissues, especially for their potential association with neurodegenerative diseases like Alzheimer's disease. In this paper, we provide a comprehensive overview of sources, analysis methods, environmental impacts, and health risks of magnetic FexOy NP. Currently, most researches are primarily based on engineered FexOy NP, while reports about magnetic FexOy NP existing in real-world environments are still limited, especially for their occurrence levels in various environmental matrices, environmental transformation behavior, and biotoxic effects. Our study reviews this emerging pollutant, providing insights to address current research deficiencies and chart the course for future studies.

Hazardous effects of nickel ferrite nanoparticles and nickel chloride in early life stages of the freshwater snail Biomphalaria glabrata (Say, 1818)

Nickel ferrite nanoparticles (NiF NPs) have growing applications in biomedical and nanomedicine fields. However, knowledge concerning their ecotoxicity during the early developmental stages of invertebrates, such as gastropods, remains scarce. Thus, the current study aimed to evaluate whether NiF NPs and nickel chloride (NiCl2) induce toxic effects on embryos and newly hatched snails of freshwater species Biomphalaria glabrata (Say, 1818). NiF NPs were synthesized and characterized by multiple techniques, and their ecotoxicity was assessed by Biomphalaria embryotoxicity test (BET) during 144 h of exposure and an acute toxicity test (96 h) using newly hatched snails. NiF NPs induced mortality, developmental delay, reduced hatching rate, and promoted morphological changes in B. glabrata. Also, NiF NPs induced higher toxicity in embryos than in newly hatched B. glabrata. Overall, results showed that the early developmental stages of gastropods are a target group for nanoparticle toxicity in freshwater ecosystems.

Tuning Biocompatibility and Bactericidal Efficacy as a Function of Doping of Gold in ZnO Nanocrystals

Doping nanoparticles represents a strategy for modulating the energy levels and surface states of nanocrystals (NCs), thereby enhancing their efficiency and mitigating toxicity. Thus, we herein focus on the successful synthesis of pure and gold (Au)-doped zinc oxide (ZnO) nanocrystals (NCs), investigating their physical-chemical properties and evaluating their applicability and toxicity through in vitro and in vivo assessments. The optical, structural, and photocatalytic characteristics of these NCs were scrutinized by using optical absorption (OA), X-ray diffraction (XRD), and methylene blue degradation, respectively. The formation and doping of the NCs were corroborated by the XRD and OA results. While the introduction of Au as a dopant did induce changes in the phase and size of ZnO, a high concentration of Au ions in ZnO led to a reduction in their photocatalytic activity. This demonstrated a restricted antibacterial efficacy against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. Remarkably, Au-doped counterparts exhibited enhanced biocompatibility in comparison to ZnO, as evidenced in both in vitro (murine macrophage cells) and in vivo (Drosophila melanogaster) studies. Furthermore, confocal microscopy images showed a high luminescence of Au-doped ZnO NCs in vivo. Thus, this study underscores the potential of Au doping of ZnO NCs as a promising technique to enhance material properties and increase biocompatibility.

In vivo assessment of the toxic impact of exposure to magnetic iron oxide nanoparticles (IONPs) using Drosophila melanogaster

Iron oxide nanoparticles (IONPs) have useful properties, such as strong magnetism and compatibility with living organisms which is preferable for medical applications such as drug delivery and imaging. However, increasing use of these materials, especially in medicine, has raised concerns regarding potential risks to human health. In this study, IONPs were coated with silicon dioxide (SiO2), citric acid (CA), and polyethylenimine (PEI) to enhance their dispersion and biocompatibility. Both coated and uncoated IONPs were assessed for genotoxic effects on Drosophila melanogaster. Results showed that uncoated IONPs induced genotoxic effects, including mutations and recombinations, while the coated IONPs demonstrated reduced or negligible genotoxicity. Additionally, bioinformatic analyses highlighted potential implications of induced recombination in various cancer types, underscoring the importance of understanding nanoparticle-induced genomic instability. This study highlights the importance of nanoparticle coatings in reducing potential genotoxic effects and emphasizes the necessity for comprehensive toxicity assessments in nanomaterial research.

Investigating the toxic mechanism of iron oxide nanoparticles-induced oxidative stress in tadpole (Duttaphrynus melanostictus): A combined biochemical and molecular study

Metal oxide nanomaterials have toxicity towards aquatic organisms, especially microbes and invertebrates, but little is known about their impact on amphibians. We conducted a study on Duttaphrynus melanostictus (D. melanostictus) tadpoles to explore the chronic toxicity effects of iron oxide nanoparticles (IONPs) and the underlying mechanisms of IONPs-induced oxidative stress. IONPs exposure led to increased iron accumulation in the blood, liver, and kidneys of tadpoles, significantly affecting blood parameters and morphology. Higher IONPs concentrations (10 and 50 mg L-1) triggered reactive oxygen species generation, resulting in lipid peroxidation, oxidative stress, and pronounced toxicity in tadpoles. The activity levels of antioxidant enzymes/proteins (SOD, CAT, albumin, and lysozyme) decreased after IONPs exposure, and immunological measures in the blood serum were significantly reduced compared to the control group. Molecular docking analysis revealed that IONPs primarily attached to the surface of SOD/CAT/albumin/lysozyme through hydrogen bonding and hydrophobic forces. Overall, this study emphasizes the ability of IONPs to induce oxidative damage by decreasing immunological profiles such as ACH50 (34.58 ± 2.74 U mL-1), lysozyme (6.94 ± 0.82 U mL-1), total Ig (5.00 ± 0.35 g dL-1), total protein (1.20 ± 0.17 g dL-1), albumin (0.52 ± 0.01 g dL-1) and globulin (0.96 ± 0.01 g dL-1) and sheds light on their potential toxic effects on tadpoles.

Microplastics and TiO2 nanoparticles mixture as an emerging threat to amphibians: A case study on bullfrog embryos

Emerging contaminants can act as contributing factors to the decline of amphibian populations worldwide. Recently, scientists have drawn attention to the potential ecotoxicity of microplastics and nanomaterials in amphibians, however, their possible effects on embryonic developmental stages are still absent. Thus, the present study analyzed the developmental toxicity of environmentally relevant concentrations of polyethylene microplastics (PE MPs; 60 mg/L) and titanium dioxide nanoparticles (TiO2 NPs; 10 μg/L), isolated or in combination (Mix group) on bullfrog embryos, Aquarana catesbeiana, adapting the Frog Embryo Teratogenesis Assay (FETAX, 96h). Allied to the FETAX protocol, we also analyzed the heart rate and morphometric data. The exposure reduced the survival and hatching rates in groups exposed to TiO2 NPs, and to a lesser extent, also affected the Mix group. TiO2 NPs possibly interacted with the hatching enzymes of the embryos, preventing hatching, and reducing their survival. The reduced effects in the Mix group are due to the agglomeration of both toxicants, making the NPs less available for the embryos. PE MPs got attached to the gelatinous capsule of the chorion (confirmed by fluorescence microscopy), which protected the embryos from eventual direct effects of the microplastics on the hatching and survival rates. Although there were no cardiotoxic effects nor morphometric alterations, there was a significant increase in abdominal edemas in the hatched embryos of the PE MPs group, which indicates that osmoregulation might have been affected by the attachment of the microplastics on the embryos' gelatinous capsule. This study presents the first evidence of developmental toxicity of environmental mixtures of microplastics and nanoparticles on amphibians and reinforces the need for more studies with other amphibian species, especially neotropical specimens that could present bigger sensibility. Our study also highlighted several features of the FETAX protocol as useful tools to evaluate the embryotoxicity of several pollutants on amphibians.

Evaluation of the Genotoxic and Histological Effects in Neotropical Fish Prochilodus Lacustris (Pisces, Prochilodontidae) in Conservation Area of the Brazilian Northeast

Human activities significantly impact the aquatic biota in lacustrine environments, leading to negative environmental consequences. Due to this, this study was carried out to evaluate the genotoxic and histological biomarkers in the gills and kidneys of Prochilodus lacustris. The collection of fish and water was conducted in three distinct stations (S1, S2, S3) in an international protected area in northeast Brazil. The histological alterations index was used to assess changes in the gills and kidneys at a histological level. In addition, micronucleus and nuclear abnormalities tests were employed to examine damage to the genetic material. According to the frequency of Micronucleus, nuclear injuries, and the histopathology of gills and kidneys, it can be inferred that station S1 had the highest impact on the fish, causing significant harm. Based on our findings, the organisms residing in Lake Açu are adversely affected by the poor environmental conditions. This raises doubts about the effectiveness of the Protection Area by Humid Zone of International Interest in Northeast Brazil.

Iron oxide nanoparticles in the soil environment: Adsorption, transformation, and environmental risk

Iron oxide nanoparticles (IONPs) have great application potential due to their multifunctional excellence properties, leading to the possibility of their release into soil environments. IONPs exhibit different adsorption properties toward environmental pollutants (e.g., heavy metals and organic compounds), thus the adsorption performance for various contaminants and the molecular interactions at the IONPs-pollutants interface are discussed. After solute adsorption, the change in the environmental behavior of IONPs is an important transformation process in the natural environments. The aggregation, aging process, and chemical/biological transformation of IONPs can be altered by soil solution chemistry, as well as by the presence of dissolved organic matter and microorganisms. Upon exposure to soil environments, IONPs have both positive and negative impacts on soil organisms (e.g., bacteria, plants, nematodes, and earthworms). Moreover, we compared the toxicity of IONPs alone to combined toxicity with environmental pollutants and pristine IONPs to aged IONPs, and the mechanisms of IONPs toxicity at the cellular level are also reviewed. Given the unanswered questions, future research should include prediction and design of IONPs, new characterization technology for monitoring IONPs transformation in soil ecosystems, and further refinement the environmental risk assessment of IONPs. This review will greatly enhance our knowledge of the performance and impact of IONPs in soil systems.

Co-exposure of iron oxide nanoparticles with glyphosate herbicides in Poecilia reticulata: Fish liver damages is reversible during iron accumulation and elimination period

Iron oxide nanoparticles (IONPs) are advanced materials for water remediation technologies. It is therefore relevant to evaluate the cellular and tissue behavior of fishes in response to IONPs and their associations with agrochemicals such as glyphosate (GLY) and glyphosate-based herbicides (GBHs). Iron accumulation, tissue integrity and lipid distribution in the hepatocytes of Poecilia reticulata (guppy) were investigated in a control group and in groups exposed to soluble iron ions, namely IFe (0.3 mgFe/L), IONPs (0.3 mgFe/L), and IONPs, associated with GLY (0.65 mg/L), GBHs 0.65 mgGLY/L (IONPs + GBH1), and 1.30 mgGLY/L (IONPs + GBH2), for 7, 14, and 21 days, followed by an equal period of postexposure in clean reconstituted water. The results showed that the accumulation of iron was greater in the subjects in the IONP treatment group when compared to that in the Ife group. In addition, the subjects in the mixtures with GBHs had a greater accumulation of iron than those in the IONP + GLY treatment group. Tissue integrity assessments demonstrated an intense accumulation of lipids, formation of necrotic zones and leukocyte infiltrates in all the treated groups, with a greater quantity of lipids in the animals treated with IONP + GLY and IFe. During postexposure, the results indicated an elimination of iron in all treated groups, reaching the same level as the control group, throughout the 21 days postexposure. Thus, the damage caused to animal livers by IONP mixtures is reversible, providing promising results for the development of safe environmental remediation practices using nanoparticles.

Iron nanoparticle regulate succinate dehydrogenase activity in canola plants under drought stress

Application of nutrients as nanoparticle (NP) is an operative manner of nutrient supply for plants, especially under stress conditions. The present study was designed to highlight the role of iron NP on drought tolerance and elucidate the underlying mechanisms in drought-stressed canola plants. Drought stress was imposed by polyethylene glycol different concentrations (0, 10 and 15% (W/V)) with or without iron NP (1.5 and 3 mg/l). A comparative study of several physiological and biochemical parameters have been carried out in canola plants treated by drought and iron NP. Stressed-canola plants showed a reduction in growth parameters, whereas iron NP mostly stimulated growth of stressed plants, which was accompanied by reinforcement in defense mechanisms. Regarding impacts on compatible osmolytes, the data revealed that iron NP was able to regulate osmotic potential by increasing protein, proline and soluble sugar contents. The iron NP application was activated the enzymatic defense system (catalase and polyphenol oxidase) and promoted the non-enzymatic antioxidants (phenol, flavonol and flavonoid). Both of these adaptive responses declined free radicals as well as lipid peroxidation and enhanced the membrane stability and drought tolerance of the plants. Enhanced chlorophyll accumulation via induction of protoporphyrin, magnesium protoporphyrin and protochlorophyllide, by iron NP also contributed towards better stress tolerance. Enzymes of Krebs cycle, namely succinate dehydrogenase and aconitase, were induced by iron NP in canola plants grown under drought stress. These results propose a multifaceted involvement of iron NP, through regulation of activity of respiratory enzymes and antioxidant enzymes, production of reactive oxygen species, osmoregulation and secondary metabolites metabolism, in response to drought stress.

Ovaries of guppies (Poecilia reticulata) investigated in pre-embryonic, embryonic and post-embryonic stages after exposure to maghemite nanoparticles (y-Fe2O3) associated with Roundup® and glyphosate, followed by recovery period evaluation

Iron oxide nanoparticles (IONP) are promising alternatives to environmental remediation, so this study investigates IONP single and associated to contaminants, in this case, glyphosate (GLY) and Roundup® (GBH) in Poecilia reticulata (guppy). The guppies have internal development, therefore this study analyzed female gonads to establish the developmental stages of P. reticulata and evaluate effects of exposure (7, 14 and 21 days) and post-exposure (same period) to the treatments with Iron ions 0.3mg Fe/L (IFe); IONP 0.3mg Fe/L; IONP 0.3 mgFe/L + GBH 0,65mgGLY/L (IONP+GBH1); IONP 0.3 mgFe/L + GBH 1.30 mgGLY/L (IONP+GBH2); and IONP 0.3 mgFe/L + GLY 0.65 mg/L (IONP+GLY). The development was organized in immature, development, and gestation phases. The damage in all treatments after 21 days of exposure was evident in reaction patterns regressive inflammatory, and circulatory including total histopathologic index of liver, nevertheless there was a damage recovery trend during post-exposure period.

First report on the toxicity of SARS-CoV-2, alone and in combination with polyethylene microplastics in neotropical fish

The COVID-19 pandemic has caused unprecedented negative impacts in the modern era, including economic, social, and public health losses. On the other hand, the potential effects that the input of SARS-CoV-2 in the aquatic environment from sewage may represent on non-target organisms are not well known. In addition, it is not yet known whether the association of SARS-CoV-2 with other pollutants, such as microplastics (MPs), may further impact the aquatic biota. Thus, we aimed to evaluate the possible ecotoxicological effects of exposure of male adults Poecilia reticulata, for 15 days, to inactivated SARS-CoV-2 (0.742 pg/L; isolated SARS.CoV2/SP02.2020.HIAE.Br) and polyethylene MP (PE MPs) (7.1 × 10⁴ particles/L), alone and in combination, from multiple biomarkers. Our data suggest that exposure to SARS-CoV-2 induced behavioral changes (in the open field test), nephrotoxic effect (inferred by the increase in creatinine), hepatotoxic effect (inferred by the increase in bilirubin production), imbalance in the homeostasis of Fe, Ca, and Mg, as well as an anticholinesterase effect in the animals [marked by the reduction of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity]. On the other hand, exposure to PE MPs induced a genotoxic effect (assessed by the comet assay), as well as an increase in enzyme activity alpha-amylase, alkaline phosphatase, and carboxylesterases. However, we did not show synergistic, antagonistic, or additive effects caused by the combined exposure of P. reticulata to SARS-CoV-2 and PE MPs. Principal component analysis (PCA) and values from the "Integrated Biomarker Response" index indicate that exposure to SARS-CoV-2 was determinant for a more prominent effect in the evaluated animals. Therefore, our study sheds light on the ecotoxicity of the new coronavirus in non-target organisms and ratifies the need for more attention to the impacts of COVID-19 on aquatic biota.

Co-exposure of iron oxide nanoparticles and glyphosate-based herbicide promote liver toxicity in guppy (Poecilia reticulata): A histochemical and ultrastructural approach

Citrate functionalized iron oxide nanoparticles (IONPs) are employed for various purposes-including environmental remediation but the interaction of IONPs with aquatic contaminants is poorly understood. Among those, glyphosate-based herbicides are toxic and affect target organs such as the liver. Evaluations of livers of female Poecilia reticulata by exposures to IONPs at a concentration of 0.3 mg/L were performed with association to: (1) 0.65 mg of glyphosate per litter and (2) 1.3 mg of glyphosate per litter of Roundup Original, and (3) glyphosate P.A at 0.65 mg/L. These associations were carried out progressively, after 7, 14, and 21 days. We detected circulatory disturbances, inflammatory responses, activation of the immune system, regressive changes, and progressive responses with changes in the connective tissue and decreased glycogen reserve from days 14 to 21. Ultrastructural changes in the Disse space and microvilli of hepatocytes indicated decreased contact surface area. In general, the damage was time and concentration dependent, increasing from 7 to 14 days and tending to stabilize from 14 to 21 days. Therefore, herbicide-associated IONPs functioned as xenobiotics inducing intense cellular detoxification processes and activation of hepatic immune responses.

Titanium dioxide nanoparticles as a risk factor for the health of Neotropical tadpoles: a case study of Dendropsophus minutus (Anura: Hylidae)

The production and use of titanium dioxide (TiO₂) nanoparticles are increasing worldwide. The release of this substance into the environment can induce toxic effects in aquatic invertebrates and vertebrates, although the exact nature of its impacts on Neotropical amphibians is still poorly understood. In this context, the present study evaluated the toxicity of TiO₂ nanoparticles and their counterpart-dissolved titanium dioxide (TiO₂)-in the tadpoles of Dendropsophus minutus. The biometric parameters, DNA damage, and behavioral changes were verified in tadpoles exposed to three different concentrations (0.1 mg·L^-1, 1.0 mg·L^-1, and 10 mg·L^-1) of TiO₂ nanoparticles and dissolved TiO₂ for 7 days. We verified significant DNA damage in the D. minutus tadpoles exposed to both forms of Ti, in comparison with the control group. We also identified a reduction in total size, body length, and width, and the height of the musculature of the tail of the tadpoles exposed to all concentrations of both substances in comparison with the control. In the behavioral test, the tadpoles exposed to nanoparticles and dissolved TiO₂ presented reduced mobility and a tendency to be less aggregated than normal. Here, the simultaneous use of multiple biomarkers was fundamental for the reliable assessment of the adverse effects of nanomaterials on anuran amphibians and the establishment of a systematic approach to the biomonitoring of aquatic ecosystems. The present study expands our understanding of the genotoxic, morphological, and behavioral effects of TiO₂ nanoparticles and dissolved TiO₂ on anuran amphibians, and contributes to the establishment of further research for the more systematic assessment of the environmental risk of nanomaterials.

Lauric acid bilayer-functionalized iron oxide nanoparticles disrupt early development of freshwater snail Biomphalaria glabrata (Say, 1818)

Iron oxide nanoparticles (IONPs) have been indicated for the control of parasites and intermediate hosts, as well as applications in several sectors of nanomedicine. However, knowledge regarding its toxicity, mechanisms of action and the role of functionalization in gastropods that act as intermediate hosts of neglected disease parasites is still scarce. The present study aimed to evaluate the toxicity of lauric acid bilayer-functionalized IONPs (LA-IONPs), lauric acid isolated (LA) and iron ions in embryos and newly-hatched Biomphalaria glabrata. The snails were exposed to different concentrations of IONPs, LA and iron ions (1.0-97.65 mg L^-1) during 144 h (embryos) and 96 h (newly-hatched) and multiple parameters were analyzed, such as mortality, hatching rate, developmental delay, and morphological changes. The results showed that both iron forms (LA-IONPs and iron ions) and LA promoted mortality, hatching inhibition and morphological changes in snail embryos in a concentration-dependent patterns. Embryos also showed iron bioaccumulation after exposure to both iron forms. High toxicity was observed in newly-hatched snails compared to embryos, indicating the protective role of ovigerous masses during the early developmental stages. LA induced high developmental toxicity compared to LA-IONPs and iron ions. Results showed the molluscicide activity of LA-IONPs and isolated LA, indicating their potential use as molluscicide in the snail control program.

Do Manganese and Iron in Association Cause Biochemical and Genotoxic Changes in Oreochromis Niloticus (Teleostei: Cichlidae)?

The present study aimed to evaluate the toxicity of the association between Fe and Mn in Oreochromis niloticus through genotoxic (micronucleus test and comet assay) and biochemical (CAT and GST enzymes) assays. The tested treatments were T1 = control group (without metal addition), T2 = 2.60 mg L^-1 of Fe + 0.2 mg L^-1 of Mn, and T3 = 4.40 mg L^-1 of Fe + 3.49 mg L^-1 of Mn, during 96-h bioassays. All animals exposed to the metals showed a significant increase in erythrocyte micronucleus frequency and DNA damage. The hepatic GST activity increased two times in animals exposed to T3 compared to the control group. The results indicate that Fe + Mn caused genotoxic and biochemical changes in exposed fish. Therefore, excess metals in ecosystems, even those essential for organisms, can be dangerous for the local biota due to the risk associated with high concentrations of these metals.

Investigation of genotoxicity, mutagenicity, and cytotoxicity in erythrocytes of Nile tilapia (Oreochromis niloticus) after fluoxetine exposure

Fluoxetine (FLX) is an antidepressant that is increasingly being detected in aquatic environments. However, this contaminated FLX can affect aquatic organisms. Therefore, the aim of this study was to evaluate the genotoxic, mutagenic, and cytotoxic potential of FLX on erythrocytes in Nile tilapia (Oreochromis niloticus) after acute exposure. Fish were exposed to different concentrations of FLX (10, 100 and 1000 µg/L) for 96 h. Then, the condition factor (K value) was used to assess the general fish condition. The genotoxicity was investigated using a comet assay, and the mutagenicity was examined using micronucleus (MN) and erythrocytic nuclear abnormalities (ENAs) assays. In addition, the cytotoxicity was analyzed by erythrocyte morphometry and erythrocyte maturity index (EMI). The results showed that FLX did not affect the fish's health. Nevertheless, 100 and 1000 µg/L FLX significantly increased DNA damage. Furthermore, a higher concentration of FLX presented a significantly increased frequency of MNs and ENAs, also leading to changes in some erythrocyte morphometric indices and significantly decreased mature erythrocytes. In conclusion, our results indicate that FLX induces genotoxic, mutagenic, and cytotoxic effects in erythrocytes of O. niloticus.

Effect of benzophenone-3 on the blood cells of zebrafish (Danio rerio)

Benzophenone-3 (BP-3) is a common component of organic sunscreen widely used that can affect especially aquatic ecosystems health, including fish. To verify the biological effects of low concentrations of BP-3 on blood cells, one hundred and forty zebrafish (D. rerio) were used and then randomly divided into five groups: control group (water), solvent group (alcoholic water), and BP-3 group (BP-3 at 7 µg L^-1, BP-3 at 70 µg L^-1, and BP-3 at 700 µg L^-1). The blood slices were stained with Panoptic stain and with Giemsa solution for the hematological analysis. During the exposure to BP-3, no behavioral changes were observed. Although no significant difference in total leukocytes occurred, an increase in neutrophils and a reduction of lymphocytes at the highest concentration on both 7th and 14th days were detected. The total and cytoplasmic area of erythrocytes on the 7th day at the highest concentration were reduced. In addition, alterations on the erythrocyte nuclear morphology in fish exposed to BP-3 were usually visualized, mainly when considered the occurrence of blebbed nucleus and micronucleus, indicating that BP-3 exhibits cytotoxic and mutagenic effects. The results indicate that BP-3 can interfere with the morphophysiology of aquatic organisms.

Treatment of cosmetic industry wastewater by flotation with Moringa oleifera Lam. and aluminum sulfate and toxicity assessment of the treated wastewater

The production of personal hygiene and body products generates wastewater with a high load of surfactants, a high chemical oxygen demand (COD), and abundant oils and greases. Aluminum sulfate (AS) and two solutions of natural coagulant from Moringa oleifera Lam. seeds prepared with a 1M NaCl solution and 1.5M NaCl solution were used. Aluminum sulfate, Moringa oleifera Lam. in 1M NaCl, and Moringa oleifera Lam. in 1.5M NaCl solutions reduced turbidity at rates 94.48%, 98.07%, and 97.87%; reduced COD at rates 46.36%, 49.15%, and 42.7%; and reduced oil and grease at rates 98.72%, 78.65%, and 97.41%, respectively. Mutagenicity tests with guppies showed a lower toxicity of Moringa oleifera Lam. extract compared with aluminum sulfate. This work shows that Moringa oleifera Lam. extract has high potential for use as an alternative to aluminum sulfate; therefore, this study will contribute to proposals for the sustainable treatment of effluents from the cosmetic industry.

Distribution and behavior of lipid droplets in hepatic cells analyzed by variations of citochemical technique and scanning electron microscopy

Toxicity evaluations involve the analysis of multiple biomarkers. In this study, the liver, target organ analyzed by treatments with iron concentrations, indicated the accumulation of lipids as a response. Considering that the distribution of lipids in an organ is directly related to the induction of inflammatory processes by aquatic contaminants, this study proposes to carry out an integrative investigation of the behavior and the distribution of lipids in the liver tissue. Techniques of light and electron microscopy were performed in order to propose a new way of assessing and quantifying the distribution of lipid droplets, also presenting methodological alternatives that can be chosen by the reader according to the interests and resources available. Thus, it is assumed that the method begins with the fixation of the liver with Glutaraldehyde 2,5% in PBS 0,1 M and continues with post fixation with osmium tretoxide 1%, which marks lipids. For this proposition, two inclusion methodologies were performed to histological analyses in Historesin and ultrastructural analyses in EMBeed 812. For light microscopy (LM) analyses, cuts were obtained with 2,5 micrometers thickness, which were stained with (1) Mayers hematoxylin and (2) toluidine blue. The images obtained were processed in software Image J Fiji to evidence the lipid distribution in liver.•

Cytological reactions with osmium tetroxide constitute low complexity methods that allow the optimization of the localization, identification and quantification of lipid droplets in the liver tissue when analyzed under the conventional light microscope.

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Samples included in EMBeed 812 resin commonly used in Transmission Electron Microscopy can be analyzed by SEM-BEC, as complementary analyses for the detection of lipids.

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Using SEM-BEC and conventional light microscopy, it is possible to quantify the area occupied by lipid droplets using Image J Fiji software, as these are contrasted due to the reaction with osmium tetroxide.

Micronucleus test and nuclear abnormality assay in zebrafish (Danio rerio): Past, present, and future trends

Nuclear abnormality (NA) assay in fish has been widely applied for toxicity risk assessment under field and laboratory conditions. The zebrafish (Danio rerio) has become a suitable model system for assessing the NA induced by pollutants. Thus, the current study aimed to summarize and discuss the literature concerning micronucleus (MN) and other NA in zebrafish and its applications in toxicity screening and environmental risk assessment. The data concerning the publication year, pollutant type, experimental design, and type of NA induced by pollutants were summarized. Also, molecular mechanisms that cause NA in zebrafish were discussed. Revised data showed that the MN test in zebrafish has been applied since 1996. The MN was the most frequently NA, but 15 other nuclear alterations were reported in zebrafish, such as notched nuclei, blebbed nuclei, binucleated cell, buds, lobed nuclei, bridges, and kidney-shaped. Several pollutants can induce NA in zebrafish, mainly effluents (mixture of pollutants), agrochemicals, and microplastics. The pollutant-induced NA in zebrafish depends on experimental design (i.e., exposure time, concentration, and exposure condition), developmental stages, cell/tissue type, and the type of pollutant. Besides, research gaps and recommendations for future studies are indicated. Overall, the current study showed that zebrafish is a suitable model to assess pollutant-induced mutagenicity.

Recovery trend to co-exposure of iron oxide nanoparticles (γ-Fe2O3) and glyphosate in liver tissue of the fish Poecilia reticulata

Citrate-coated iron oxide nanoparticles (IONPs) have potential use in environmental remediation, with possibilities in decontaminating aquatic environments exposed to toxic substances. This study analyzed IONPs associated to Roundup Original, a glyphosate-based herbicide (GBH), and pure glyphosate (GLY), through ultrastructural and histopathological biomarkers in liver tissue, from females of Poecilia reticulata exposed to: iron ions (0.3 mg/L) (IFe) and IONPs (0.3 mgFe/L) associated with GLY (0.65 mg/L) and GBH (0.65 mgGLY/L (IONP + GBH1) and 1.30 mgGLY/L (IONP + GBH2)) for a period of 7, 14 and 21 days, followed by an equal post-exposure period only in reconstituted water. For the assays, the synthetized IONPs had crystalline and rounded shape with an average diameter of 2,90 nm, hydrodynamic diameter 66,6 mV, zeta potential -55,4 and diffraction profile of maghemite (γ-Fe2O3). The data obtained by biomarkers indicated a high inflammatory response in all treatments. These same parameters, considered during the post-exposure period indicated recovery in reaction patterns of circulatory disturbances and regressive changes, resulting in average reductions of 37,53 points in IFe, 21 points in IONP + GBH1, 15 points in IONP + GBH2 and 11 points in IONP + GLY in total histopathological index of liver after 21 days post-exposure. However, although the cellular and tissue responses were significant, there was no change in the condition factor and hepatosomatic index, denoting resilience of the experimental model.

DNA damage induced by cylindrospermopsin on different tissues of the biomonitor fish Poecilia reticulata

The cyanotoxin cylindrospermopsin (CYN) is the second biggest cause of poisoning worldwide, both in humans and animals. Although CYN primarily affects the aquatic environments and can be absorbed in fishes by multiple routes, data reporting its toxicity and mechanism of action are still scarce in this group. Using P. reticulata as model species, it was evaluated whether CYN promotes mutagenic and genotoxic effects in different fish target tissues. Adult females were exposed in a static way to 0 (control), 0.5, 1.0, and 1.5 μg L^-1 of pure CYN for 24 and 96 hours. For the first time, DNA damage was detected in fish brain after CYN exposition. In brain cells, a concentration-response DNA damage was observed for both exposure times, suggesting a direct or indirect action of CYN in neurotoxicity. For the liver cells, 96 hours caused an increase in DNA damage, as well the highest percentage of DNA in the tail was reached when used 1.5 μg L^-1 of CYN. In peripheral blood cells, an increase in DNA damage was observed for all tested concentrations after 96 hours. In erythrocytes, micronuclei frequency was higher at 1.5 μg L^-1 treatment while the erythrocyte nuclear abnormalities (ENA) frequency was significantly higher even at the lowest CYN concentration. Such data demonstrated that acute exposition to CYN promotes genotoxicity in the brain, liver, and blood cells of P. reticulata, as well mutagenicity in erythrocytes. It rises an alert regarding to the toxic effects of CYN for aquatic organisms as well as for human health.

Manganese doped iron-carbon composite for synergistic persulfate activation: Reactivity, stability, and mechanism

The heterogeneous catalytic process has been under development for aqueous pollutant degradation, yet electron transfer efficiency often limits the effectiveness of catalytic reactions. In this study, a novel composite material, manganese doped iron-carbon (Mn-Fe-C), was tailor designed to promote the catalytic electron transfer. The Mn-Fe-C composite, synthesized via a facile carbothermal reduction method, was characterized and evaluated for its performance to activate persulfate (PS) and degrade Rhodamine Blue (RhB) dye under different pH, catalyst dosages, PS dosages, and pollutant concentrations. Electron spin resonance, along with quenching results by ethanol, tert-butanol, phenol, nitrobenzene and benzoquinone, indicated that surface bounded SO₄^•- was the main contributor for RhB degradation, while the roles of aqueous SO₄^•- and ^•OH were very minor. Through characterization by XRD, XPS and FTIR analysis, it was determined that the electron transfer during activation of PS was accelerated by the oxygen functional groups on catalyst surface and the promoted redox cycle of Fe³⁺ and Fe²⁺ by Mn. Finally, the Mn-Fe-C composite catalyst exhibited an excellent reusability and stability with negligible leached Fe and Mn ions in solutions. Results of this study provide a promising design for heterogeneous catalysts that can effectively activate PS to remove organic pollutants from water at circumneutral pH conditions.

Risk assessment of iron oxide nanoparticles in an aquatic ecosystem: A case study on Biomphalaria glabrata

Iron oxide nanoparticles (IONPs) have been applied in several sectors in the environmental field, such as aquatic nanoremediation, due to their unique superparamagnetic and nanospecific properties. However, the knowledge of chronic toxicity of IONPs on aquatic invertebrate remains limited. Thus, the present study aimed to analyze the chronic toxicity of gluconic acid-functionalized IONPs (GLA-IONPs) and their dissolved counterpart (FeCl₃) to freshwater snail Biomphalaria glabrata. GLA-IONPs were synthesized and characterized by multiple techniques, and the snails were exposed to both Fe forms at environmentally relevant concentrations (1.0-15.6 mg L^-1) for 28 days. The bioaccumulation, mortality rate, behavior impairments, morphological alterations, fecundity and fertility of snails were analyzed. Results showed that GLA-IONPs induced high iron bioaccumulation in the entire soft tissue portion. Chronic exposure to GLA-IONP increased the behavioral impairments of snails compared to iron ions and control groups. Both Fe forms reduced the fecundity, while the mortality and reduced fertility were observed only after the exposure to GLA-IONPs at 15.6 mg L^-1. Overall results indicated the behavioral impairments and reproductive toxicity associated, possibly, to bioaccumulation of GLA-IONPs in the B. glabrata. These results can be useful for the development of eco-friendly nanotechnologies.

Co-exposure of iron oxide nanoparticles and glyphosate-based herbicide induces DNA damage and mutagenic effects in the guppy (Poecilia reticulata)

Iron oxide nanoparticles (IONPs) have been tested to remediate aquatic environments polluted by chemicals, such as pesticides. However, their interactive effects on aquatic organisms remain unknown. This study aimed to investigate the genotoxicity and mutagenicity of co-exposure of IONPs (γ-Fe2O3 NPs) and glyphosate-based herbicide (GBH) in the fish Poecilia reticulata. Thus, fish were exposed to citrate-functionalized γ-Fe2O3 NPs (0.3 mg L-1; 5.44 nm) alone or co-exposed to γ-Fe2O3 NPs (0.3 mg L-1) and GBH (65 and 130 μg of glyphosate L-1) during 14 and 21 days. The genotoxicity (DNA damage) was analyzed by comet assay, while the mutagenicity evaluated by micronucleus test (MN test) and erythrocyte nuclear abnormalities (ENA) frequency. The co-exposure induced clastogenic (DNA damage) and aneugenic (nuclear alterations) effects on guppies in a time-dependent pattern. Fish co-exposed to NPs and GBH (130 μg glyphosate L-1) showed high DNA damage when compared to NPs alone and control group, indicating synergic effects after 21 days of exposure. However, mutagenic effects (ENA) were observed in the exposure groups after 14 and 21 days. Results showed the potential genotoxic and mutagenic effects of maghemite NPs and GBH co-exposure to freshwater fish. The transformation and interaction of iron oxide nanoparticles with other pollutants, as herbicides, in the aquatic systems are critical factors in the environmental risk assessment of metal-based NPs.

Toxicity of engineered nanomaterials to aquatic and land snails: A scientometric and systematic review

The emerging growth of nanotechnology has attracted great attention due to its application in the parasite and intermediate host control. However, the knowledge concerning the mechanism of action (MoA) and toxicity of nanomaterials (NMs) to snails remain unclear. In this context, the present study revised the historical use of snails as experimental models in nanotoxicological studies and summarized the MoA and toxicity of NMs in aquatic and land snails. The data concerning the bioaccumulation, reproductive and transgenerational toxicity, embryotoxicity, genotoxicity and potential molluscicidal activity of NMs were revised. Furthermore, the data about the experimental conditions, such as exposure time, concentrations, cell and tissue-specific responses, snail species and nanoparticle types are discussed. Revised data showed that the toxic effects of NMs were reported for 21 snail species with medical, veterinary and ecological importance. The NM toxicity to snails is dependent on the physical and chemical properties of NMs, as well as their environmental transformation and experimental design. The NM bioaccumulation on snails was related to several toxic effects, such as reactive oxygen species (ROS) production, oxidative stress, following by oxidative damage to DNA, lipids and proteins. The NM metabolism in snails remains unknown. Results showed the potential use of NMs in the snail control program. Also, significant research gaps and recommendations for future researches are indicated. The present study confirms that snails are suitable invertebrate model system to assess the nanotoxicity.

Toxicity and trophic transfer of polyethylene microplastics from Poecilia reticulata to Danio rerio

The potential transfer of microplastics (MPs) between vertebrates belonging to the same taxonomic group, and the impact of such a transfer on higher trophic levels remains little explored. An experimental food chain with two fish species was installed to test the hypothesis that polyethylene MPs (PE MPs) can accumulate in animals and cause behavioral, mutagenic and cytotoxic changes at upper trophic levels. Poecilia reticulata fry were exposed to MPs for 48 h and, subsequently, offered (as food) to Danio rerio adults for 10 days to simulate an upper level food chain. PE MPs quantification in fry and in different Danio rerio tissues evidenced their accumulation at the two assessed trophic levels. This finding suggested their absorption, adherence and translocation from one organism to another. The accumulation seen in D. rerio directly exposed to MPs was associated with behavioral disorders at upper trophic level. These animals presented behavior suggestive of anti-predatory response deficit when they were confronted with a potential aquatic predator (Geophagus brasiliensis). This finding was inferred through lower school cohesion, shallower school depth and shorter distance from the potential predator. In addition, animals exposed to MPs recorded higher nuclear abnormality rates and changes in the size and shape of erythrocytes and in their nuclei; this outcome has suggested mutagenic and cytotoxic effects, respectively. Based on the current results, MPs are transferred through a food chain that only involves two vertebrates. MPs enter the vertebrates' organs, change their behavior and induce mutagenic and cytotoxic processes in animals, which can cause significant ecological consequences in freshwater ecosystems.

Molluscicidal activity of polyvinylpyrrolidone (PVP)-functionalized silver nanoparticles to Biomphalaria glabrata: Implications for control of intermediate host snail of Schistosoma mansoni

Silver nanoparticles (Ag NPs) have been applied in several commercial products due to their antimicrobial properties, while their molluscicide properties, mode of action and toxicity to snail species remain unclear. In this study, the comparative toxicity of polyvinylpyrrolidone (PVP)-functionalized Ag NPs and their dissolved counterpart (Ag ions) was analyzed during the early developmental stages of the freshwater snail Biomphalaria glabrata, intermediate host of Schistosoma mansoni. Ag NPs were synthesized and characterized by multiple techniques, and the snail embryotoxicity was analyzed in terms of mortality, hatching, developmental stages and morphological alterations, while the acute toxicity to newly-hatched snails was analyzed by mortality and behavioral impairments. Results showed that both Ag forms induced mortality, hatching delay and morphological alterations (especially hydropic abnormalities) in snail embryos in a concentration and exposure time dependent patterns. Ag NPs showed low embryotoxic effects and similar toxicity for newly-hatched snails when compared to their dissolved counterparts, indicating that the nanotoxicity was dependent of snail developmental stages. The knowledge about the Ag NP toxicity to different early development stages of B. glabrata contributes to its potential use as molluscicide and control of neglected tropical diseases, including schistosomiasis.

Comparative developmental toxicity of iron oxide nanoparticles and ferric chloride to zebrafish (Danio rerio) after static and semi-static exposure

Iron oxide nanoparticles (IONPs) are used in several medical and environmental applications, but their mechanism of action and hazardous effects to early developmental stages of fish remain unknown. Thus, the present study aimed to assess the developmental toxicity of citrate-functionalized IONPs (γ-Fe₂O₃ NPs), in comparison with its dissolved counterpart, in zebrafish (Danio rerio) after static and semi-static exposure. Embryos were exposed to environmental concentrations of both iron forms (0.3, 0.6, 1.25, 2.5, 5 and 10 mg L^-1) during 144 h, jointly with negative control group. The interaction and distribution of both Fe forms on the external chorion and larvae surface were measured, following by multiple biomarker assessment (mortality, hatching rate, neurotoxicity, cardiotoxicity, morphological alterations and 12 morphometrics parameters). Results showed that IONPs were mainly accumulated on the zebrafish chorion, and in the digestive system and liver of the larvae. Although the IONPs induced low embryotoxicity compared to iron ions in both exposure conditions, these nanomaterials induced sublethal effects, mainly cardiotoxic effects (reduced heartbeat, blood accumulation in the heart and pericardial edema). The semi-static exposure to both iron forms induced high embryotoxicity compared to static exposure, indicating that the nanotoxicity to early developmental stages of fish depends on the exposure system. This is the first study concerning the role of the exposure condition on the developmental toxicity of IONPs on fish species.

Exposure effects of iron oxide nanoparticles and iron salts in blackfish (Capoeta fusca): Acute toxicity, bioaccumulation, depuration, and tissue histopathology

We assessed the toxicity of iron oxide nanoparticles compared with iron salts in the blackfish (Capoeta fusca). After an acute toxicity assessment, we conducted a chronic exposure to a sub-lethal concentration of Fe₃O₄ NPs, and iron salts (ferric nitrate (Fe(NO₃)₃), ferric chloride (FeCl₃), ferrous sulfate (FeSO₄)) to measure iron uptake over a period of 28 days and then subsequent clearance of the iron uptake in the exposed fish that were transferred to clean water for 28 days. Fe(NO₃)₃ was the most acutely toxic compound followed by FeCl₃, FeSO₄, and Fe₃O₄ NPs. Exposure to Fe₃O₄ NPs and iron salts induced histopathology anomalies in both gills and intestine that included aneurism, hyperplasia, oedema, fusion of lamellae, lamellar synechiae, and clear signs of necrosis (in the gills) and increases in the number of goblet cells, blood cell counts, and higher numbers of lymphocyte (in the intestine). Fe₃O₄ NPs showed a higher level of uptake in the body tissues compared with iron salts (p < 0.05) with levels of Fe in the gill > intestine > liver > kidney. Fe was shown to be eliminated most efficiently from the gills, followed by the kidney, then liver and finally the intestine. The highest tissue bioconcentration factors (BCF) occurred in the liver for FeCl₃, Fe₃O₄ NPs, and FeSO₄ and in the gills for Fe(NO₃)₃. We thus show differences in the patterns of tissue accumulation, clearance and toxicological responses for exposures to Fe₃O₄ NPs and iron salts in blackfish with implications for different susceptibilities for biological effects.

Using native and invasive livebearing fishes (Poeciliidae, Teleostei) for the integrated biological assessment of pollution in urban streams

Invasive species are increasingly replacing native species, especially in anthropogenically transformed or polluted habitats. This opens the possibility to use invasive species as indicator taxa for the biological assessment of pollution. Integrated biological assessment, however, additionally relies on the application of multiple approaches to quantify physiological or cytogenetic responses to pollution within the same focal species. This is challenging when species are restricted to either polluted or unpolluted sites. Here, we make use of a small group of neotropical livebearing fishes (family Poeciliidae) for the integrated biological assessment of water quality. Comparing urban and suburban stream sections that receive varying degrees of pollution from industrial and domestic waste waters in and around the Brazilian city of Uberlândia, we demonstrate that two members of this family may indeed serve as indicators of water pollution levels. The native species Phalloceros caudimaculatus appears to be replaced by invasive guppies (Poecilia reticulata) at heavily polluted sites. Nevertheless, we demonstrate that both species could be used for the assessment of bioaccumulation of heavy metals (Pb, Cu, and Cr). Ambient (sediment) concentrations predicted concentrations in somatic tissue across species (R²-values between 0.74 and 0.96). Moreover, we used cytogenetic methods to provide an estimate of genotoxic effects of water pollution and found pollution levels (multiple variables, condensed into principal components) to predict the occurrence of nuclear abnormalities (e.g., frequencies of micro-nucleated cells) across species (R² between 0.69 and 0.83). The occurrence of poeciliid fishes in urban and polluted environments renders this family a prime group of focal organisms for biological water quality monitoring and assessment. Both species could be used interchangeably to assess genotoxic effects of water pollution, which may facilitate future comparative analyses over extensive geographic scales, as members of the family Poeciliidae have become invasive in tropical and subtropical regions worldwide.

Acute exposure to environmentally relevant concentrations of benzophenone-3 induced genotoxicity in Poecilia reticulata

The organic UV filter benzophenone-3 (BP-3), widely used in the commercial formulations of sunscreens and personal care products, is considered an emerging pollutant and has been associated with several human and environmental health concerns. However, knowledge about their mode of action and ecotoxicity on aquatic biota is scarce. In this scenario, the objective of this work was to evaluate the genotoxic, mutagenic, and erythrotoxicity effects of BP-3 in the guppy Poecilia reticulata after acute exposure. Adult females of P. reticulata were exposed to three non-lethal and environmentally relevant concentrations of BP-3 (10, 100, and 1000 ng L^-1) during 96 h of exposure, and the somatic parameter [Fulton condition factor (K)], genotoxicity (comet assay), mutagenicity [micronucleus (MN) and erythrocyte nuclear abnormalities (ENA) tests] and erythrotoxicity parameters (such as total cell area and nucleus-cytoplasmic ratio) were analyzed. Results showed that the general physiological condition (K value) of fish was not affected by acute exposure to BP-3. However, BP-3 induced DNA damage at 100 and 1000 ng L^-1 and increased the frequency of total ENA at 1000 ng L^-1, specially lobed nucleus, when compared to control group, indicating its genotoxic and mutagenic effects. Furthermore, the BP-3 did not induce significant changes in the total cell area and nucleus-cytoplasmic ratio. In summary, results showed that the BP-3 at environmentally relevant concentration was genotoxic to freshwater fish P. reticulata, confirming its environmental risk.

Prolonged mosquitocidal activity of Siparuna guianensis essential oil encapsulated in chitosan nanoparticles

Background

The use of synthetic insecticides is one of the most common strategies for controlling disease vectors such as mosquitos. However, their overuse can result in serious risks to human health, to the environment, as well as to the selection of insecticidal resistant insect strains. The development of efficient and eco-friendly insect control is urgent, and essential oils have been presented as potential alternatives to synthetic insecticides. Moreover, nanoencapsulation techniques can enhance their efficiency by protecting from degradation and providing a controlled release rate.

Results

We assessed the potential of chitosan nanoparticles in encapsulating Siparuna guianensis essential oil, and maintaining its efficiency and prolonging its activity for the control of Aedes aegypti larvae. The encapsulation was characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), with an encapsulation efficiency ranging from 84.8% to 88.0%. Toxicity studies have demonstrated efficacy against mosquito larvae over 50% for 19 days with 100% mortality during the first week. This persistent action is presumably due to the enhanced contact and slow and maintained release conferred by chitosan nanoparticles. Furthermore, the exposure of aquatic non-target organisms (e.g. embryos and small adult fishes) revealed adequate selectivity of these nanoparticles.

Conclusions

The encapsulation of S. guianensis essential oil in chitosan nanoparticles showed promising potential as a larvicide control alternative and should be considered within strategies for fighting Ae. aegypti.

Numerous outbreaks of infectious diseases such as dengue, zika, and chikungunya in tropical countries have occurred where the mosquito Aedes aegypti is the transmitting vector. In Brazil, these infections are responsible for deaths and severe sequelae. Thus, many efforts have been made by governmental and research groups to control these outbreaks. However, complete success in this control has so far remained unachieved. Parallel to the need to develop new technologies that contribute to the control of insects that transmit diseases, there is a growing societal awareness regarding the risks associated with the use of synthetic insecticides, which has led to a search for natural alternatives such as essential oils from plants. Thus, our group conducted experiments to evaluate the application of nanotechnology in obtaining an efficient prolonged release system to combat Ae. aegypti larvae using the essential oil of a plant native to the Cerrado and Amazonian forests. These results demonstrate that using a simple and easily scalable encapsulation technique; it is possible to keep the low toxicity against non-target organism and prolong the activity of an essential oil in water and maintain larval mortality at a significant level for more than a week with a single application.

Red blood cells as an efficient in vitro model for evaluating the efficacy of metallic nanoparticles

Blood and the linings of blood vessels may be regarded as a fifth tissue type. The human body contains 5 × 10⁹ red blood cells (RBCs) per ml, a total of 2.5 × 10¹³ cells in the 5 l of blood present in the body. With an average lifetime of 125 days, human RBCs are destroyed by leukocytes in the spleen and liver. Nowadays red blood cells are extensively used to study various metabolic functions. Nanoparticles (NP) are being widely accepted for drug delivery system. This review summarizes the red blood cells, NPs and their characteristics on the basis of the RBC components along with drug delivery systems through RBCs. Further, we also discussed that how erythrocytes can be used as an efficient in vitro model for evaluating the efficacy of various nanocomposite materials.

The comet assay in animal models: From bugs to whales - (Part 2 Vertebrates)

The comet assay has become one of the methods of choice for the evaluation and measurement of DNA damage. It is sensitive, quick to perform and relatively affordable for the evaluation of DNA damage and repair at the level of individual cells. The comet assay can be applied to virtually any cell type derived from different organs and tissues. Even though the comet assay is predominantly used on human cells, the application of the assay for the evaluation of DNA damage in yeast, plant and animal cells is also quite high, especially in terms of biomonitoring. The present extensive overview on the usage of the comet assay in animal models will cover both terrestrial and water environments. The first part of the review was focused on studies describing the comet assay applied in invertebrates. The second part of the review, (Part 2) will discuss the application of the comet assay in vertebrates covering cyclostomata, fishes, amphibians, reptiles, birds and mammals, in addition to chordates that are regarded as a transitional form towards vertebrates. Besides numerous vertebrate species, the assay is also performed on a range of cells, which includes blood, liver, kidney, brain, gill, bone marrow and sperm cells. These cells are readily used for the evaluation of a wide spectrum of genotoxic agents both in vitro and in vivo. Moreover, the use of vertebrate models and their role in environmental biomonitoring will also be discussed as well as the comparison of the use of the comet assay in vertebrate and human models in line with ethical principles. Although the comet assay in vertebrates is most commonly used in laboratory animals such as mice, rats and lately zebrafish, this paper will only briefly review its use regarding laboratory animal models and rather give special emphasis to the increasing usage of the assay in domestic and wildlife animals as well as in various ecotoxicological studies.

Neuroligin-2-derived peptide-covered polyamidoamine-based (PAMAM) dendrimers enhance pancreatic β-cells' proliferation and functions

Pancreatic β-cell membranes and presynaptic areas of neurons contain analogous protein complexes that control the secretion of bioactive molecules. These complexes include the neuroligins (NLs) and their binding partners, the neurexins (NXs). It has been recently reported that both insulin secretion and the proliferation rates of β-cells increase when cells are co-cultured with full-length NL-2 clusters. The pharmacological use of full-length protein is always problematic due to its unfavorable pharmacokinetic properties. Thus, NL-2-derived short peptide was conjugated to the surface of polyamidoamine-based (PAMAM) dendrimers. This nanoscale composite improved β-cell functions in terms of the rate of proliferation, glucose-stimulated insulin secretion (GSIS), and functional maturation. This functionalized dendrimer also protected β-cells under cellular stress conditions. In addition, various novel peptidomimetic scaffolds of NL-2-derived peptide were designed, synthesized, and conjugated to the surface of PAMAM in order to increase the biostability of the conjugates. However, after being covered by peptidomimetics, PAMAM dendrimers were inactive. Thus, the original peptide-based PAMAM dendrimer is a leading compound for continued research that might provide a unique starting point for designing an innovative class of antidiabetic therapeutics that possess a unique mode of action.

Environmentally Sustainable and Ecosafe Polysaccharide-Based Materials for Water Nano-Treatment: An Eco-Design Study

Nanoremediation, which is the use of nanoparticles and nanomaterials for environmental remediation, is widely explored and proposed for preservation of ecosystems that suffer from the increase in human population, pollution, and urbanization. We herein report a critical analysis of nanotechnologies for water remediation by assessing their sustainability in terms of efficient removal of pollutants, appropriate methods for monitoring their effectiveness, and protocols for the evaluation of any potential environmental risks. Our purpose is to furnish fruitful guidelines for sustainable water management, able to promote nanoremediation also at European level. In this context, we describe new nanostructured polysaccharide-based materials obtained from renewable resources as alternative efficient and ecosafe solutions for water nano-treatment. We also provide eco-design indications to improve the sustainability of the production of these materials, based on life-cycle assessment methodology.

Regulation of lipid peroxidation and ferroptosis in diverse species

This review by Conrad et al. reviews the functions and regulation of lipid peroxidation, ferroptosis, and the antioxidant network in diverse species, including humans, other mammals and vertebrates, plants, invertebrates, yeast, bacteria, and archaea, and discusses the potential evolutionary roles of lipid peroxidation and ferroptosis.

Lipid peroxidation is the process by which oxygen combines with lipids to generate lipid hydroperoxides via intermediate formation of peroxyl radicals. Vitamin E and coenzyme Q₁₀ react with peroxyl radicals to yield peroxides, and then these oxidized lipid species can be detoxified by glutathione and glutathione peroxidase 4 (GPX4) and other components of the cellular antioxidant defense network. Ferroptosis is a form of regulated nonapoptotic cell death involving overwhelming iron-dependent lipid peroxidation. Here, we review the functions and regulation of lipid peroxidation, ferroptosis, and the antioxidant network in diverse species, including humans, other mammals and vertebrates, plants, invertebrates, yeast, bacteria, and archaea. We also discuss the potential evolutionary roles of lipid peroxidation and ferroptosis.

DNA methylation alterations induced by transient exposure of MCF-7 cells to maghemite nanoparticles

AIM

To evaluate the DNA methylation profile of MCF-7 cells during and after the treatment with maghemite nanoparticles (MNP-CIT).

MATERIALS & METHODS

Noncytotoxic MNP-CIT concentrations and cell morphology were evaluated by standard methods. DNA methylation was assessed by whole genome bisulfite sequencing. DNA methyltransferase (DNMT) genes expression was analyzed by qRT-PCR.

RESULTS

A total of 30 and 60 µgFeml^-1 MNP-CIT accumulated in cytoplasm but did not present cytotoxic effects. The overall percentage of DNA methylation was not affected, but 58 gene-associated regions underwent DNA methylation reprogramming, including genes related to cancer onset. DNMT transcript levels were also modulated.

CONCLUSION

Transient exposure to MNP-CIT promoted epigenomic changes and altered the DNMT genes regulation in MCF-7 cells. These events should be considered for biomedical applications.