Effect of silver nanoparticles on gill membranes of common carp: Modification of fatty acid profile, lipid peroxidation and membrane fluidity

Impact of the novel chlorinated polyfluorinated ether sulfonate, F-53B, on gill structure and reproductive toxicity in zebrafish

6:2 Chlorinated polyfluorinated ether sulfonate, commonly known as F-53B, is widely used as a mist suppressant in various industries and is frequently detected in the environment. Despite its prevalent presence, the adverse effects of F-53B are not well understood and require future investigation. This study utilized zebrafish embryos and adults to examine the toxic effects of F-53B. Our findings revealed that F-53B impaired gill structure and increased erythrocyte numbers in adult zebrafish. Notably, F-53B demonstrated a higher sensitivity for inducing mortality (LC50 at 96 h) in adult zebrafish compared to embryos. Additionally, F-53B disrupted the expression of critical steroidogenic genes and hindered sex hormone production, which negatively affecting egg production. In conclusion, this study underscores the detrimental impact of F-53B on gill structure and reproductive toxicity in zebrafish, providing valuable insights into its overall toxicity.

Mass Spectrometry Imaging Reveals the Morphology-Dependent Toxicological Effects of Nanosilvers on Multiple Organs of Adult Zebrafish (Danio rerio)

Nanosilvers with multifarious morphologies have been extensively used in many fields, but their morphology-dependent toxicity toward nontarget aquatic organisms remains largely unclear. Herein, we used matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to investigate the toxicological effects of silver nanomaterials with various morphologies on spatially resolved lipid profiles within multiple organs in adult zebrafish, especially for the gill, liver, and intestine. Integrated with histopathology, enzyme activity, accumulated Ag contents and amounts, as well as MSI results, we found that nanosilvers exhibit morphology-dependent nanotoxicity by disrupting lipid levels and producing oxidative stress. Silver nanospheres (AgNSs) had the highest toxicity toward adult zebrafish, whereas silver nanoflakes (AgNFs) exhibited greater toxicity than silver nanowires (AgNWs). Levels of differential phospholipids, such as PC, PE, PI, and PS, were associated with nanosilver morphology. Notably, we found that AgNSs induced greater toxicity in multiple organs, such as the brain, gill, and liver, while AgNWs and AgNFs caused greater toxicity in the intestine than AgNSs. Lipid functional disturbance and oxidative stress further caused inflammation and membrane damage after exposure to nanosilvers, especially with respect to sphere morphology. Taken together, these findings will contribute to clarifying the toxicological effects and mechanisms of different morphologies of nanosilvers in adult zebrafish.

Silver Nanoparticles Supported onto TEMPO-Oxidized Cellulose Nanofibers for Promoting Cd2+ Cation Adsorption

Nanocellulose constitutes a sustainable and biobased solution both as an efficient sorbent material for water treatment and as support for other inorganic nanomaterials with sorbent properties. Herein, we report the synthesis of a nanocomposite by deposition of in situ-generated silver nanoparticles (AgNPs) onto TEMPO-oxidized cellulose nanofibers (TOCNFs). Following an in-depth analytical investigation, we unveil for the first time the key role of AgNPs in enhancing the adsorption efficiency of TOCNF toward Cd2+ ions, chosen as model heavy metal contaminants. The obtained nanocomposite shows a value of Cd2+ sorption capacity at equilibrium from 150 mg L-1 ion aqueous solutions of ∼116 mg g-1 against the value of 78 mg g-1 measured for TOCNF alone. A combination of field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX), and X-ray photoelectron spectroscopy (XPS) analyses suggests that Cd2+ ions are mainly adsorbed in the neighborhood of AgNPs. However, XPS characterization allows us to conclude that the role of AgNPs relies on increasing the exposure of carboxylic groups with respect to the original TOCNF, suggesting that these groups are still responsible for absorption. In fact, X-ray absorption spectroscopy (XAS) analysis of the Cd-K edge excludes a direct interaction between Ag0 and Cd2+, supporting the XPS results and confirming the coordination of the latter with carboxyl groups.

Biogenic silver nanoparticles: Synthesis, applications and challenges in food sector with special emphasis on aquaculture

Aquaculture, a rapidly expanding global food sector faces challenges like pathogenic infections, water quality management and sustainability. Silver nanoparticles (AgNPs) have emerged as promising tools in aquaculture due to their antimicrobial, antiviral and antifungal properties. AgNPs offer alternatives to traditional antimicrobial agents. Their small size and unique physicochemical properties enhance antimicrobial activity, effectively inhibiting pathogen growth and reducing disease incidence in aquatic organisms. Additionally, AgNPs can improve water quality by catalyzing the removal of pollutants, heavy metals and nutrients, reducing environmental impacts. Despite their potential benefits, several challenges and knowledge gaps exist in the utilization of AgNPs in aquaculture. Addressing challenges related to regulation, sustainability and environmental impact will be crucial for realizing their full potential in the industry. Therefore, the present review aims to provide insight into the role of AgNPs, its challenges in aquaculture and also highlights key areas for future research.

Unveiling potentially convergent key events related to adverse outcome pathways induced by silver nanoparticles via cross-species omics-scale analysis

The adverse effects of silver nanoparticles (AgNPs) have been studied in various models. However, there has been discordance between molecular responses across the literature, attributed to methodological biases and the physicochemical variability of AgNPs. In this study, a gene pathway meta-analysis was conducted to identify convergent and divergent key events (KEs) associated with AgNPs and explore common patterns of these KEs across species. We performed a cross-species analysis of transcriptomic data from multiple studies involving various AgNPs exposure. Pathway enrichment analysis revealed a set of pathways linked to oxidative stress, apoptosis, and metabolite and lipid metabolism, which are considered potentially conserved KEs across species. Subsequently, experiments confirmed that oxidative stress responses could be early KEs in both Caenorhabditis elegans and HepG2 cells. Moreover, AgNPs preferentially impaired the mitochondria, as evidenced by mitochondrial fragmentation and dysfunction. Furthermore, disruption of amino acids, nucleotides, sulfur compounds, glycerolipids, and glycerophospholipids metabolism were in good agreement with gene pathway shreds of evidence. Our findings imply that, although there may be organism-specific responses, potentially conserved events could exist regardless of species and physicochemical factors. These results provide valuable insights into the development of adverse outcome pathways of AgNPs across species and the regulatory toxicity of AgNPs.

Acute sublethal exposure to ethiprole impairs physiological and oxidative status in the Neotropical fish Astyanax altiparanae

Ethiprole, a phenylpyrazole insecticide, has been increasingly used in the Neotropical region to control stink bug pests in soybean and maize fields. However, such abrupt increases in use may have unintended effects on non-target organisms, including those inhabiting freshwater ecosystems. Here, we evaluated the effects of acute (96 h) sublethal exposure to ethiprole (up to 180 μg/L, which is equivalent to 0.013% of the recommended field dose) on biomarkers of stress in the gills, liver, and muscle of the Neotropical fish Astyanax altiparanae. We further recorded potential ethiprole-induced effects on the structural histology of A. altiparanae gills and liver. Our results showed that ethiprole exposure increased glucose and cortisol levels in a concentration-dependent manner. Ethiprole-exposed fish also exhibited higher levels of malondialdehyde and greater activity of antioxidant enzymes, such as glutathione-S-transferase and catalase, in both gills and liver. Furthermore, ethiprole exposure led to increased catalase activity and carbonylated protein levels in muscle. Morphometric and pathological analyses of the gills revealed that increasing ethiprole concentration resulted in hyperemia and loss of integrity of the secondary lamellae. Similarly, histopathological analysis of the liver demonstrated higher prevalence of necrosis and inflammatory infiltrates with increasing ethiprole concentration. Altogether, our findings demonstrated that sublethal exposure to ethiprole can trigger a stress response in non-target fish species, which may lead to potential ecological and economic imbalances in Neotropical freshwater systems.

Beneficial Effect of Wound Dressings Containing Silver and Silver Nanoparticles in Wound Healing-From Experimental Studies to Clinical Practice

Impaired wound healing affects hundreds of million people around the world; therefore, chronic wounds are a major problem not only for the patient, but also for already overloaded healthcare systems. Chronic wounds are always very susceptible to infections. Billions of dollars are spent to discover new antibiotics as quickly as possible; however, bacterial resistance against antibiotics is rising even faster. For this reason, a complete shift of the antibacterial treatment paradigm is necessary. The development of technology has allowed us to rediscover well-known agents presenting antimicrobial properties with a better outcome. In this context, silver nanoparticles are a promising candidate for use in such therapy. Silver has many useful properties that can be used in the treatment of chronic wounds, such as anti-bacterial, anti-inflammatory, and anti-oxidative properties. In the form of nanoparticles, silver agents can work even more effectively and can be more easily incorporated into various dressings. Silver-based dressings are already commercially available; however, innovative combinations are still being discovered and very promising results have been described. In this review article, the authors focused on describing experimental and clinical studies exploring dressings containing either silver or silver nanoparticles, the results of which have been published in recent years.

Proteomic profiling reveals mitochondrial toxicity of nanosilver and silver nitrate in the gill of common carp

Mitochondria are recognized as an important target organelle for the toxicity of nanomaterials. Although the toxic effects of silver nanoparticles (AgNPs) on mitochondria have been widely reported, the mechanism behind the toxicity remains unclear. In this study, the effects of two forms of silver (AgNPs and AgNO₃) on carp gill mitochondria were investigated by analyzing the mitochondrial ultrastructure, physicochemical properties of mitochondrial membrane, and mitochondrial proteomics. After exposure of common carp to AgNPs (0.75 mg/L) and AgNO₃ (0.05 mg/L) for 96 h, both forms of silver were shown to cause gill mitochondrial lesions, including irregular shape, loss of mitochondrial cristae, and increased mitochondrial membrane permeability. Proteomics results revealed that AgNPs and AgNO₃ induced 362 and 297 differentially expressed proteins (DEPs) in gill mitochondria, respectively. Among the DEPs, 244 were shared between AgNPs and AgNO₃ treatments. These shared proteins were mainly distributed in the mitochondrial membrane and matrix, and were significantly enriched in the tricarboxylic acid (TCA) cycle and oxidative phosphorylation pathway. The functional annotation of DEPs induced by both silver forms was mainly involved in energy production and conversion. These results indicated that the toxic mechanism of AgNPs and AgNO₃ on gill mitochondria were comparable and the two forms of silver caused mitochondrial dysfunction in fish gills by inhibiting the TCA cycle and disrupting the electron transport chain.

Impacts of engineered iron nanoparticles on oxidative stress, fatty acid composition, and histo-architecture of the smooth scallop Flexopecten glaber

Engineered iron nanoparticles are widely used in environmental remediation, yet their potential toxic effects on marine biota remain poorly elucidated. This study aimed to gain insight into the nanoscale zero-valent iron (NZVI) toxicity mechanisms for marine invertebrates. Aside from the effect on oxidative status and histopathology, the effect of NZVI on lipid metabolism in bivalves was studied for the first time. To this end, specimens of Flexopecten glaber were exposed to ascending concentrations (0.5, 1, and 1.5 mg/L) of NZVI for 96 h. Results illustrate differential patterns of iron accumulation in the gills and the digestive gland. By increasing NZVI concentrations, the total iron level tended to markedly increase in the gills and decrease in the digestive gland, reaching 132 and 37.6 μg/g DW, respectively, in the specimens exposed to 1.5 mg/L. Biochemical and cellular biomarkers highlighted that NZVI caused oxidative stress (measured as hydrogen peroxide, malondialdehyde, and advanced oxidation protein product levels) and alterations of antioxidant defense systems, including reduced glutathione, non-protein thiol, glutathione peroxidase, superoxide dismutase, and catalase. Modulation of lipid metabolism with changed fatty acid compositions (mainly an increase in the saturation and a decrease in unsaturation levels) was also observed in both gills and digestive gland. Moreover, several histological damages, including lipofuscin accumulation, infiltrative inflammations, and digestive tubule alterations, were observed in the two studied organs, providing supplementary evidence regarding the toxic effect of NZVI. This study adds to the growing body of evidence pointing to the hazardous impacts of iron NPs on aquatic ecosystems.

Purifying water with silver nanoparticles (AgNPs)-incorporated membranes: Recent advancements and critical challenges

In the face of the growing global water crisis, membrane technology is a promising means of purifying water and wastewater. Silver nanoparticles (AgNPs) have been widely used to improve membrane performance, for antibiofouling, and to aid in photocatalytic degradation, thermal response, and electro-conductivity. However, several critical issues such as short antimicrobial periods, trade-off effects and silver inactivation seriously restrict the engineering application of AgNPs-incorporated membranes. In addition, there is controversy around the use of AgNPs given the toxic preparation process and environmental/biological risks. Hence, it is of great significance to summarize and analyze the recent developments and critical challenges in the use of AgNPs-incorporated membranes in water and wastewater treatment, and to propose potential solutions. We reviewed the different properties and functions of AgNPs and their corresponding applications in AgNPs-incorporated membranes. Recently, multifunctional, novel AgNP-incorporated membranes combined with other functional materials have been developed with high-performance. We further clarified the synergistic mechanisms between AgNPs and these novel nanomaterials and/or polymers, and elucidated their functions and roles in membrane separation. Finally, the critical challenges of AgNPs-incorporated membranes and the proposed solutions were outlined: i) Prolonging the antimicrobial cycle through long-term and controlled AgNPs release; ii) Overcoming the trade-off effect and organic fouling of the AgNPs-incorporated membranes; iii) Preparation of sustainable AgNPs-incorporated membranes; iv) Addressing biotoxicity induced by AgNPs; and v) Deactivation of AgNPs-incorporated membrane. Overall, this review provides a comprehensive discussion of the advancements and challenges of AgNPs-incorporated membranes and guides the development of more robust, multi-functional and sustainable AgNPs-incorporated membranes.

Evaluation of antioxidant response and Na+-K+-ATPase activity in zebrafish exposed to polyethylene microplastics: Shedding light on a physiological adaptation

Although the toxicity of microplastics has already been demonstrated in different animal models, our knowledge about the response of freshwater fish to this pollutant is still limited. Thus, we aimed to evaluate the impact of exposure of zebrafish adults (Danio rerio) to environmentally relevant concentrations of polyethylene microplastics (PE-MPs) (5 and 50 µg/L) and at different times of exposure (10 and 20 days). Initially, scanning electron microscope image illustrated size and format of the particle and FTIR analysis confirmed the presence of PE-MPs in the gastrointestinal tract of fish (at both concentrations tested). Subsequently, an alteration of oxidative and antioxidant responses was evaluated in the liver and brain. The results showed that catalase (CAT) activity, in liver, was significantly decreased, as was glutathione S-transferases (GSTs) activity (on the 10th experimental day). However, after 20 days of exposure, we observed a concentration-dependent increase in GST activity in liver of the animals exposed to PE-MPs. Furthermore, the lipid peroxidation (LPO) level was significantly increased by exposure to MPs, especially in the brain, after 20 days of exposure. The increase in Na⁺-K⁺-ATPase activity in the animals' gills was correlated with the increased production of malondialdehyde (MDA), which suggests the existence of a compensatory mechanism in which the high activity of this enzyme would be necessary to regulate the loss of ions caused by the increase in the processes of LPO, which has never been previously demonstrated. Thus, our study sheds light on a new physiological adaptation to deal with the oxidative effects of PE-MPs, in addition to supporting the future use of the assessment of Na⁺/K⁺-ATPase activity as a biomarker of the toxicity of these pollutants.

Microplastics: A tissue-specific threat to microbial community and biomarkers of discus fish (Symphysodon aequifasciatus)

As detriments in aquatic environments, microplastics (MPs) have been commonly studied on organisms, but tissue-scale effects of MPs were poorly understood. Discus fish (Symphysodon aequifasciatus), herewith, were exposed to polystyrene MPs (0/20/200 μg/L) for 28 d. We found that MPs significantly inhibited growth performance. MPs were observed in skin, gill and intestine after 14/28-d exposure. MPs bioaccumulation was independent of exposure time, but increased with MPs concentrations. Microbial community diversity of fish gill, but not skin and intestine, in MPs treatments was significantly increased. Bacterial community of MP-treated skin and gill were obviously separated from control. Skin dominant phyla changed from Actinobacteriota to Proteobacteria and Firmicutes. Proteobacteria gradually occupied dominance in gill after exposure. Furthermore, MPs-induced skin oxidative stress was demonstrated by the activation of superoxide dismutase and catalase. Skin malondialdehyde also increased and showed significant correlations with four bacterial phyla, e.g., Proteobacteria. Gill Na⁺/K⁺-ATPase activity decreased, strongly correlating to microbial community changes caused by MPs. Intestinal digestive enzymes activity (pepsin, lipase and α-amylase) reduced, revealing correlation with bacterial community especially Fibrobacterota. These results suggest a tissue-specific effect of MPs to microbial community and biomarkers in aquatic organism.

Acute Exposure to Biogenic Nanosilver Produced from Fusarium oxysporum in a Neotropical Fish

Biogenic nanosilver (bNAg) has emerged as a potentially less toxic alternative to synthetic nanosilver. However, no studies have evaluated its effects on a fish species from the Neotropical region. Thus, our aim was to evaluate the effects of a bNAg on the Neotropical fish Prochilodus lineatus. For this purpose, after 24 h of exposure to 100 µg L^-1 of bNAg, blood samples were collected to evaluate hematological, genotoxic, and plasma parameters. Gills and liver were sampled to evaluate biomarkers of oxidative stress and brain samples were used to assess neurotoxicity. The fish presented hyperglycemia, an increased number of erythrocytes, a reduction in antioxidant enzyme activity in both tissues evaluated, and a decrease in lipid peroxidation in the gills. We concluded that P. lineatus is a sensitive species to this nanoparticle, since it presented alterations in several biomarkers after an acute exposure.

The mechanism of cell death induced by silver nanoparticles is distinct from silver cations

Background

Precisely how silver nanoparticles (AgNPs) kill mammalian cells still is not fully understood. It is not clear if AgNP-induced damage differs from silver cation (Ag⁺), nor is it known how AgNP damage is transmitted from cell membranes, including endosomes, to other organelles. Cells can differ in relative sensitivity to AgNPs or Ag⁺, which adds another layer of complexity to identifying specific mechanisms of action. Therefore, we determined if there were specific effects of AgNPs that differed from Ag⁺ in cells with high or low sensitivity to either toxicant.

Methods

Cells were exposed to intact AgNPs, Ag⁺, or defined mixtures of AgNPs with Ag⁺, and viability was assessed. The level of dissolved Ag⁺ in AgNP suspensions was determined using inductively coupled plasma mass spectrometry. Changes in reactive oxygen species following AgNP or Ag⁺ exposure were quantified, and treatment with catalase, an enzyme that catalyzes the decomposition of H₂O₂ to water and oxygen, was used to determine selectively the contribution of H₂O₂ to AgNP and Ag⁺ induced cell death. Lipid peroxides, formation of 4-hydroxynonenol protein adducts, protein thiol oxidation, protein aggregation, and activation of the integrated stress response after AgNP or Ag⁺ exposure were quantified. Lastly, cell membrane integrity and indications of apoptosis or necrosis in AgNP and Ag⁺ treated cells were examined by flow cytometry.

Results

We identified AgNPs with negligible Ag⁺ contamination. We found that SUM159 cells, which are a triple-negative breast cancer cell line, were more sensitive to AgNP exposure less sensitive to Ag⁺ compared to iMECs, an immortalized, breast epithelial cell line. This indicates that high sensitivity to AgNPs was not predictive of similar sensitivity to Ag⁺. Exposure to AgNPs increased protein thiol oxidation, misfolded proteins, and activation of the integrated stress response in AgNP sensitive SUM159 cells but not in iMEC cells. In contrast, Ag⁺ cause similar damage in Ag⁺ sensitive iMEC cells but not in SUM159 cells. Both Ag⁺ and AgNP exposure increased H₂O₂ levels; however, treatment with catalase rescued cells from Ag⁺ cytotoxicity but not from AgNPs. Instead, our data support a mechanism by which damage from AgNP exposure propagates through cells by generation of lipid peroxides, subsequent lipid peroxide mediated oxidation of proteins, and via generation of 4-hydroxynonenal (4-HNE) protein adducts.

Conclusions

There are distinct differences in the responses of cells to AgNPs and Ag⁺. Specifically, AgNPs drive cell death through lipid peroxidation leading to proteotoxicity and necrotic cell death, whereas Ag⁺ increases H₂O₂, which drives oxidative stress and apoptotic cell death. This work identifies a previously unknown mechanism by which AgNPs kill mammalian cells that is not dependent upon the contribution of Ag⁺ released in extracellular media. Understanding precisely which factors drive the toxicity of AgNPs is essential for biomedical applications such as cancer therapy, and of importance to identifying consequences of unintended exposures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-021-00430-1.

Metabolic profiling of nanosilver toxicity in the gills of common carp

Studies have shown silver nanoparticles (AgNPs) exposure can result in a series of toxic effects in fish gills. However, it is still unclear how AgNPs affect metabolite expression and their related molecular metabolic pathways in fish gills. In this study, we employed untargeted metabolomics to study the effects of AgNPs and silver supernatant ions on fish gill metabolites. The results showed that AgNPs can induce significant changes in 96 differentially expressed metabolites, which mainly affect amino acid metabolism and energy metabolism in fish gills. Among these metabolites, AgNPs specifically induce significant changes in 72 differentially expressed metabolites, including L-histidine, L-isoleucine, L-phenylalanine, and citric acid. These metabolites were significantly enriched in the pathways of aminoacyl-tRNA biosynthesis, ABC transporters, and the citrate cycle. In contrast, Ag⁺ supernatant exposure can specifically induce significant changes in 14 differentially expressed metabolites that mainly interfere with sphingolipid metabolism in fish gills. These specifically regulated fish gill metabolites include sphinganine, sphingosine, and phytosphingosine, which were significantly enriched in the sphingolipid metabolism pathway. Our results clearly reveal the effects and potential toxicity mechanisms of AgNPs on fish gill metabolites. Furthermore, our study further determined the unique functions of released silver ions in AgNPs toxicity in fish gills.

Low Doses of Silver Nanoparticles Selectively Induce Lipid Peroxidation and Proteotoxic Stress in Mesenchymal Subtypes of Triple-Negative Breast Cancer

Molecular profiling of tumors shows that triple-negative breast cancer (TNBC) can be stratified into mesenchymal (claudin-low breast cancer; CLBC) and epithelial subtypes (basal-like breast cancer; BLBC). Subtypes differ in underlying genetics and in response to therapeutics. Several reports indicate that therapeutic strategies that induce lipid peroxidation or proteotoxicity may be particularly effective for various cancers with a mesenchymal phenotype such as CLBC, for which no specific treatment regimens exist and outcomes are poor. We hypothesized that silver nanoparticles (AgNPs) can induce proteotoxic stress and cause lipid peroxidation to a greater extent in CLBC than in BLBC. We found that AgNPs were lethal to CLBCs at doses that had little effect on BLBCs and were non-toxic to normal breast epithelial cells. Analysis of mRNA profiles indicated that sensitivity to AgNPs correlated with expression of multiple CLBC-associated genes. There was no correlation between sensitivity to AgNPs and sensitivity to silver cations, uptake of AgNPs, or proliferation rate, indicating that there are other molecular factors driving sensitivity to AgNPs. Mechanistically, we found that the differences in sensitivity of CLBC and BLBC cells to AgNPs were driven by peroxidation of lipids, protein oxidation and aggregation, and subsequent proteotoxic stress and apoptotic signaling, which were induced in AgNP-treated CLBC cells, but not in BLBC cells. This study shows AgNPs are a specific treatment for CLBC and indicates that stratification of TNBC subtypes may lead to improved outcomes for other therapeutics with similar mechanisms of action.

Integration of transcriptomics and metabolomics reveals damage and recovery mechanisms of fish gills in response to nanosilver exposure

Toxic effects of silver nanoparticles (AgNPs) on fish gills have been widely reported but the recoverability of AgNPs-induced fish gill injuries is still unknown. In this study, combined multiomics and conventional toxicological analytical methods were used to investigate the changes in the gills of common carp responses to AgNPs (0.1 mg/L) toxicity after 24 h exposure and 7-day recovery. Conventional toxicological results showed that AgNPs exposure significantly increased silver content in gills and caused epithelial hyperplasia and lamellar fusion. After the recovery period, the silver content in fish gills significantly decreased; accompanied by the disappearance of histopathological characteristics in fish gills. Multiomics results revealed that AgNPs exposure resulted in the differential expression of 687 genes and 96 metabolites in fish gills. These differentially expressed genes (DEGs) and metabolites mainly participate in amino acid, carbohydrate, and lipid metabolisms, and are significantly enriched in the tricarboxylic acid (TCA) cycle. After the recovery period, the number of DEGs and metabolites in gills decreased to 33 and 90, respectively. Moreover, DEGs and metabolites in the TCA cycle recovered to control levels. In summary, the present study found that AgNPs-induced fish gill toxicity showed potential recoverability at molecular and phenotype levels.

Impact of Ag Nanoparticles (AgNPs) and Multimicrobial Preparation (EM) on the Carcass, Mineral, and Fatty Acid Composition of Cornu aspersum aspersum Snails

The hygienic practices on farms should reduce pathogenic microorganisms while simultaneously not harming the animals themselves; they must also not degrade the products' quality. We assessed the effect of covering feed tables with paint containing silver nanoparticles (AgNPs) and the periodic spraying of effective microorganisms (EM) on production indicators and basic chemical composition, mineral content and fatty acid profiles in the bodies of Cornu aspersum aspersum snails. The animals were divided into four groups: (1) control, (2) with feed tables covered with AgNPs paint, (3) with EM spray applied and (4) with both factors-AgNP paint and EM spray. The highest increase in Ag, Zn, Fe and Ca retention, and the remodelling of the fatty acid profile in the carcasses of snails was found to be in the group of animals in contact with the feed tables covered with AgNP paint. In the group of animals exposed to the action of EM, an increased retention of Fe, Cu, P, Mg and Zn was found.

Dietary supplementation with melatonin: influence on growth performance, oxidative stress status, and amelioration of silver nanoparticles-induced toxicity in Nile tilapia (Oreochromis niloticus)

Excessive use of silver nanoparticles (AgNPs) due to antibacterial properties can raise concerns about their release into environment and potential toxicity in aquatic organisms. Melatonin has several physiological functions especially antioxidant potential against oxidative stress. The current study was conducted to investigate the potential effects of two doses of dietary melatonin on growth performance, plasma biochemistry, and liver enzyme activity in Nile tilapia (Oreochromis niloticus) juveniles. We also investigated the potential ameliorative effect of melatonin in AgNPs-induced biochemical alterations in tilapia fish. The results showed that melatonin-supplemented diets had no significant effect on growth performance of fish (P>0.05). The liver GPx activity increased in fish fed melatonin-supplemented diets (P<0.05), but the SOD activity showed no significant difference in comparison with the control (P>0.05). The administration of melatonin-supplemented diets reduced the activity of liver MDA compared to the control (P<0.05). Feeding fish with high melatonin-supplemented diet (200 mg kg^-1 of diet) decreased the plasma glucose, total protein, and AST levels (P<0.05). The liver GPx and SOD activities were higher in high melatonin-treated fish exposed to AgNPs than the control group (P<0.05). Dietary melatonin decreased the liver MDA activity in AgNPs-exposed fish. The plasma glucose, AST, and ALT levels in melatonin-treated fish exposed to AgNPs decreased compared to the untreated exposed fish (P<0.05). Melatonin-treated fish exposed to 0.05 and 0.5 mg L^-1 of AgNPs had lower plasma LDH level than the control group (P<0.05). The results showed that consumption of melatonin-supplemented diets could modulate some of the biochemical indices of plasma and liver in Nile tilapia. The findings also indicated the ameliorative effect of dietary melatonin on AgNPs-induced toxicity in Nile tilapia.

Fatty acid alteration in liver, brain, muscle, and oocyte of zebrafish (Danio rerio) exposed to silver nanoparticles and mitigating influence of quercetin-supplemented diet

No to less effort has been made to assess the toxicity of silver nanoparticles (AgNPs) to lipid composition in biological systems and also to discover a mitigating agent against their oxidative stress. Hence, this research evaluated the antioxidant capability of quercetin (Qu) against silver nanoparticles (AgNPs) toxicity towards the lipid contents of ovarian, nervous, and hepatic systems as well as skeletal muscles. To this end, zebrafish (n = 180) were assigned into four experimental dietary groups: negative and positive controls, without Qu supplementation; Qu-200, 200 mg Qu per kg diet; and Qu-400, 400 mg Qu per kg diet. At the end of the feeding trial (40 days), the experimental groups, except the negative control, were exposed to sublethal concentration of AgNPs (0.15 mg L^-1) for 96 h. As to the liver tissue of the positive and Qu-200 treatments, total polyunsaturated fatty acids (∑PUFA) decreased 3 times, as well as total high unsaturated fatty acids (∑HUFA) reduced about 30% and 50%, respectively. However, the brain ∑HUFA, predominated by DHA, enhanced in Qu-400 treatment. Interestingly, ∑MUFA, ∑PUFA, and ∑HUFA increased in the muscle of all treated groups, especially Qu-200 and Qu-400. The oocyte ∑MUFA content increased in the positive and Qu-200 treatments, whereas ∑HUFA reduced about 25%, 25%, and 20%, respectively, in the positive, Qu-200, and Qu-400 groups. Generally, the findings suggest that unsaturated acyl chains, particularly HUFAs, in the liver tissue and oocyte cell are highly susceptible to peroxidation or degeneration by AgNPs. More broadly, in the context of ecotoxicological risk assessment, the alteration in HUFAs and PUFAs of the liver and oocyte could impact on maternal and offspring health and consequently alter long-term population dynamics of aquatic animals.

Environmental Impact of Nanoparticles' Application as an Emerging Technology: A Review

The unique properties that nanoparticles exhibit, due to their small size, are the principal reason for their numerous applications, but at the same time, this might be a massive menace to the environment. The number of studies that assess the possible ecotoxicity of nanomaterials has been increasing over the last decade to determine if, despite the positive aspects, they should be considered a potential health risk. To evaluate their potential toxicity, models are used in all types of organisms, from unicellular bacteria to complex animal species. In order to better understand the environmental consequences of nanotechnology, this literature review aims to describe and classify nanoparticles, evaluating their life cycle, their environmental releasing capacity and the type of impact, particularly on living beings, highlighting the need to develop more severe and detailed legislation. Due to their diversity, nanoparticles will be discussed in generic terms focusing on the impact of a great variety of them, highlighting the most interesting ones for the industry.

Consequences of oxidative damage on the fatty acid profile in muscle of Cichlasoma amazonarum acutely exposed to copper

Rapid industrialization results in the production of large quantities of waste that are commonly discharged into water bodies, leading to the damage of the aquatic ecosystem and freshwater organisms. Copper (Cu) can induce oxidative damage in fish muscle, the main fish portion that is consumed by humans. However, the responses of the Amazon fish Cichlasoma amazonarum and its capacity to withstand acute Cu concentrations found in Amazon water around mines remain unknown. Thus, the aim of this study was to evaluate whether exposure to Cu causes muscle oxidative stress and/or oxidative damage and impairs the fillet fatty acid profile of C. amazonarum acutely exposed to Cu found in Amazon waters around mines. Muscle reactive oxygen species and protein carbonylation levels were significantly higher in fish exposed to 1500 μg/L Cu compared with the control group, while muscle lipid peroxidation levels were significantly higher in fish exposed to 500, 750, and 1500 μg/L Cu compared with control group. Muscle antioxidant capacity against peroxyl radical's levels and glutathione peroxidase activity were significantly lower in fish exposed to 1500 μg/L Cu compared with the control group, while muscle superoxide dismutase activity was significantly lower in fish exposed to 750 and 1500 μg/L Cu compared with control group. The total content of saturated fatty acids was significantly higher in fish exposed to 1500 μg/L Cu compared with the control group, while the total content of monounsaturated fatty acids and sum of n3 fatty acids were significantly lower in fish exposed to 1500 μg/L Cu compared with control group. No significant difference was observed regarding muscle catalase, glutathione S-transferase, and glutathione reductase activities. Based on these lines of evidence, the results of this comprehensive study agree with the initial hypothesis that the exposure to Cu found in Amazon water around mines induces oxidative damage and inhibits enzymatic and non-enzymatic antioxidant response in the muscle of C. amazonarum exposed to high Cu levels. Moreover, the impairment of the fillet fatty acid profile appears to be mediated by oxidative damage, representing a negative impact on fish health.

Integrated response of growth, antioxidant defense and isotopic composition to microplastics in juvenile guppy (Poecilia reticulata)

Microplastics (MPs) pollution becomes a research hotspot and many studies focus on threats of MPs, but few have integrated multi-level indicators to assess response to MPs of organisms. Here we exposed guppy (Poecilia reticulata) to MPs (polystyrene; 32-40 μm diameter) with two concentrations (100 and 1000 μg/L) for 28 days. We found that higher accumulation of MPs appeared in guppy gill than that in gut. MPs had no obvious effect on guppy growth but significantly inhibited the condition factor. Oxidative stress presented in guppy viscera with activated antioxidants. The decline of Na⁺/K⁺-ATP activity in guppy indicated that MPs might interfere with the osmotic balance of gills. MPs reduced body molar ratio of C:N and δ¹³C value, but no apparent impact on δ¹⁵N. It implied that MPs probably altered elemental transition. Eventually, through integrated biomarkers response index (IBR) of guppy, we found that catalase activity was the highest index in response to MPs, and the response of growth performance to MPs was lower than that of oxidative stress and element alteration. Risks of MPs aggravated in a concentration-dependent manner. These findings suggested that multi-level IBR approach should be adopted to quantify effects of MPs on aquatic organisms, especially on fish.

Proteomics reveals surface electrical property-dependent toxic mechanisms of silver nanoparticles in Chlorella vulgaris

Silver nanoparticles (AgNPs) are known to exert adverse effects on both humans and aquatic organisms; however, the toxic mechanisms underlying these effects remain unclear. In this study, we investigated the toxic mechanisms of various AgNPs with different surface electrical properties in the freshwater algae Chlorella vulgaris using an advanced proteomics approach with Data-Independent Acquisition. Citrate-coated AgNPs (Cit-AgNPs) and polyethyleneimine-coated AgNPs (PEI-AgNPs) were selected as representatives of negatively and positively charged nanoparticles, respectively. Our results demonstrated that the AgNPs exhibited surface electrical property-dependent effects on the proteomic profile of C. vulgaris. In particular, the negatively charged Cit-AgNPs specifically regulated mitochondrial function-related proteins, resulting in the disruption of several associated metabolic pathways, such as those related to energy metabolism, oxidative phosphorylation, and amino acid synthesis. In contrast, the positively charged PEI-AgNPs primarily targeted ribosome function-related proteins and interrupted pathways of protein synthesis and DNA genetic information transmission. In addition, Ag⁺ ions released from the AgNPs had a significant influence on protein regulation and the induction of cellular stress. Collectively, our findings provide new insight into the surface electrical property-dependent proteomic effects of AgNPs on C. vulgaris and should improve our understanding of the toxic mechanisms of AgNPs in freshwater algae.

Exposure to microplastics impairs digestive performance, stimulates immune response and induces microbiota dysbiosis in the gut of juvenile guppy (Poecilia reticulata)

Microplastics (MPs) are widely distributing in aquatic environment. They are easily ingested by aquatic organisms and accumulate in digestive tract especially of intestine. To explore the potential effects of MPs on intestine, here we, using juvenile guppy (Poecilia reticulata) as experimental animal, investigated the response characteristics of digestion, immunity and gut microbiota. After exposure to 100 and 1000 μg/L concentrations of MPs (polystyrene; 32-40 μm diameters) for 28 days, we observed that MPs could exist in guppy gut and induce enlargement of goblet cells. Activities of digestive enzymes (trypsin, chymotrypsin, amylase and lipase) in guppy gut generally reduced. MPs stimulated the expression of immune cytokines (TNF-α, IFN-γ, TLR4 and IL-6). Through high throughput sequencing of 16S rRNA gene, decreases in diversity and evenness and changed composition of microbiota were found in guppy gut. PICRUSt analysis revealed that MPs might have effects on intestinal microbiota functions, such as inhibition of metabolism and repair pathway. Our findings suggested that MPs could retain in the gut of juvenile guppy, impair digestive performance, stimulate immune response and induce microbiota dysbiosis in guppy gut. The results obtained here provide new insights into the potential risks of MPs to aquatic animals.

The Crucial Role of Environmental Coronas in Determining the Biological Effects of Engineered Nanomaterials

In aquatic environments, a large number of ecological macromolecules (e.g., natural organic matter (NOM), extracellular polymeric substances (EPS), and proteins) can adsorb onto the surface of engineered nanomaterials (ENMs) to form a unique environmental corona. The presence of environmental corona as an eco-nano interface can significantly alter the bioavailability, biocompatibility, and toxicity of pristine ENMs to aquatic organisms. However, as an emerging field, research on the impact of the environmental corona on the fate and behavior of ENMs in aquatic environments is still in its infancy. To promote a deeper understanding of its importance in driving or moderating ENM toxicity, this study systemically recapitulates the literature of representative types of macromolecules that are adsorbed onto ENMs; these constitute the environmental corona, including NOM, EPS, proteins, and surfactants. Next, the ecotoxicological effects of environmental corona-coated ENMs on representative aquatic organisms at different trophic levels are discussed in comparison to pristine ENMs, based on the reported studies. According to this analysis, molecular mechanisms triggered by pristine and environmental corona-coated ENMs are compared, including membrane adhesion, membrane damage, cellular internalization, oxidative stress, immunotoxicity, genotoxicity, and reproductive toxicity. Finally, current knowledge gaps and challenges in this field are discussed from the ecotoxicology perspective.

Silver Nanoparticles for Water Pollution Monitoring and Treatments: Ecosafety Challenge and Cellulose-Based Hybrids Solution

Silver nanoparticles (AgNPs) are widely used as engineered nanomaterials (ENMs) in many advanced nanotechnologies, due to their versatile, easy and cheap preparations combined with peculiar chemical-physical properties. Their increased production and integration in environmental applications including water treatment raise concerns for their impact on humans and the environment. An eco-design strategy that makes it possible to combine the best material performances with no risk for the natural ecosystems and living beings has been recently proposed. This review envisages potential hybrid solutions of AgNPs for water pollution monitoring and remediation to satisfy their successful, environmentally safe (ecosafe) application. Being extremely efficient in pollutants sensing and degradation, their ecosafe application can be achieved in combination with polymeric-based materials, especially with cellulose, by following an eco-design approach. In fact, (AgNPs)-cellulose hybrids have the double advantage of being easily produced using recycled material, with low costs and possible reuse, and of being ecosafe, if properly designed. An updated view of the use and prospects of these advanced hybrids AgNP-based materials is provided, which will surely speed their environmental application with consequent significant economic and environmental impact.

Evaluation of a new Argovit as an antiviral agent included in feed to protect the shrimp Litopenaeus vannamei against White Spot Syndrome Virus infection

In this study, four experimental assays were conducted to evaluate the use of a new silver nanoparticle formulation named Argovit-4, which was prepared with slight modifications to enhance its biological activity against white spot syndrome virus (WSSV) in shrimp culture. The goals of these assays were to (1) determine the protective effect of Argovit-4 against WSSV, (2) determine whether Argovit-4 supplemented in feed exhibits toxicity towards shrimp, (3) determine whether Argovit-4 as antiviral additive in feed can prevent or delay/reduce WSSV-induced shrimp mortality, and (4) determine whether Argovit-4 supplemented in feed alters the early stages of the shrimp immune response. In bioassay 1, several viral inocula calibrated at 7 SID₅₀(shrimp infectious doses 50% endpoint) were exposed to 40, 100, 200 and 1,000 ng/SID₅₀ of Ag⁺ and then intramuscularly injected into shrimp for 96 h. In bioassay 2, shrimp were fed Argovit-4 supplemented in feed at different concentrations (10, 100 and 1,000 µg per gram of feed) for 192 h. In bioassay 3, shrimp were treated with Argovit-4 supplemented in feed at different concentrations and then challenged against WSSV for 192 h. In bioassay 4, quantitative real-time RT-qPCR was performed to measure the transcriptional responses of five immune-relevant genes in haemocytes of experimental shrimp treated with Argovit-4 supplemented in feed at 0, 6, 12, 24 and 48 h. The intramuscularly injected Argovit-4 showed a dose-dependent effect (p < 0.05) on the cumulative shrimp mortality from 0–96 h post-infection. In the second bioassay, shrimp fed Argovit-4 supplemented in feed did not show signs of toxicity for the assayed doses over the 192-h experiment. The third and fourth bioassays showed that shrimp challenged with WSSV at 1,000 µg/g feed exhibited reduced mortality without altering the expression of some immune system-related genes according to the observed level of transcriptional. This study is the first show that the new Argovit-4 formulation has potential as an antiviral additive in feed against WSSV and demonstrates a practical therapeutic strategy to control WSSV and possibly other invertebrate pathogens in shrimp aquaculture.