Effects of AgNPs on the Snail Biomphalaria glabrata: Survival, Reproduction and Silver Accumulation

Oxidative stress, histopathological and genotoxicity of copper oxide nanoparticles in Biomphalaria alexandrina snail

Higher usage of copper oxide nanomaterials in industrial and biomedical fields may cause an increase of these nanoparticles in aquatic environments, which could have a detrimental ecological effect. Thus, the objective of this study was to evaluate the acute toxicity of copper oxide nanoparticles on the freshwater gastropod, Biomphalaria alexandrina. Transmission electron microscopy, x-ray diffraction analysis and UV-VIS spectrophotometer of CuO NPs revealed a typical TEM image and a single crystal structure with average crystallite size of approximately 40 nm also, a sharp absorption band was appeared. Following exposure to sub-lethal concentrations of CuO NPs (LC10, 15.6 mg/l and LC25, 27.2 mg/l), treated snails revealed a significant decrease (p < 0.05) in total antioxidant capacity, reduced glutathione contents as well as catalase, and sodium dismutase activities were significantly declined (p < 0.05) in comparison to the control group. Also, histopathological alterations were observed in the digestive gland, including ruptured and vacuolated digestive cells, and a marked increase in the number of secretory cells and the severity of the damage increased with rising concentrations. Furthermore, changes in RAPD profiles were detected in the treated snails. In conclusion, our research highlights the potential ecological impact of CuO NPs release in aquatic ecosystems and advocates for improved monitoring and regulation of CuO NPs industrial usage and disposal.

Green synthesis of silver nanoparticles using Croton urucurana and their toxicity in freshwater snail species Biomphalaria glabrata

Green silver nanoparticles (G-Ag NPs) have contributed to the development of ecological technologies with low environmental impact and safer for human health, as well as demonstrating potential for the control of vectors and intermediate hosts. However, knowledge about its toxicity in the early stages of gastropod development remains scarce. Therefore, the current study aimed to investigate the toxicity of G-Ag NPs synthesized from Croton urucurana leaf extracts in snail species Biomphalaria glabrata, which is an intermediate host for Schistosoma mansoni parasite. G-Ag NPs were synthesized using two types of plant extracts (aqueous and hydroethanolic) and characterized using multiple techniques. Bioassays focused on investigating G-Ag NPs and plant extracts were carried out with embryos and newly hatched snails, for 144 h and 96 h, respectively; toxicity was analyzed based on mortality, hatching, development inhibition, and morphological changes. Results have shown that both G-Ag NPs were more toxic to embryos and newly hatched snails than the investigated plant extracts. G-Ag NPs deriving from aqueous extract have higher molluscicidal activity than those deriving from hydroethanolic extract. Both G-Ag NPs induced mortality, hatching delay, development inhibition, and morphological changes (i.e., hydropic embryos), indicating their molluscicidal activities. Moreover, embryos were more sensitive to G-Ag NPs than newly hatched snails. Thus, the toxicity of G-Ag NPs to freshwater snails depends on the type of extracts and the snail's developmental stages. These findings can contribute to the development of green nanobiotechnologies applicable to control snails of medical importance.

The Molluscicidal Activity of Green Synthesized Copper Oxide-Based Annona squamosa Seed Extract Nanoparticles on the Feeding Behavior, Biochemical, Molecular, and Immunohistochemical Alterations of Biomphalaria alexandrina Snails

Because of their low ecological impact, plant molluscicides have garnered much attention. The work aimed to find out if Annona squamosa (AS) seed extract has a molluscicidal impact on Biomphalaria alexandrina snails and enhances this extract by adding CuO nanoparticles (NPs). Using a scanning electron microscope (SEM), transmission electron microscope (TEM), and PANalytical X'Pert PRO X-ray diffractometer (XRD), the presence of the green A. squamosa-based CuO NPs (AS-CuO NPs) was confirmed. After 24 h of exposure, the half-lethal concentration (LC50) of AS-CuO NPs was more toxic to mature B. alexandrina than the aqueous extract of AS seeds (LC50: 119.25 mg/L vs. 169.03 mg/L). The results show that snails exposed to sublethal doses of AS-CuO NPs at LC10 or LC25 (95.4 or 106.7 mg/L, respectively) had much higher glucose levels and alkaline phosphatase activity than those not exposed. Nevertheless, there was no discernible change in the protein content in general or glycogen phosphorylase production. Histological and immunohistochemical analysis showed that snails exposed to A. squamosa-derived CuO NPs LC10 had shrinking digestive tubules and degeneration as well as vacuolation of many digestive, secretory, ova, and sperm cells, with PCNA expressing positively in the hermaphrodite gland and digestive tubule cells. The toxic profile of green CuO NPs produced by A. squamosa may damage the biological activity of B. alexandrina snails; thus, this compound could be used as a molluscicidal base. Furthermore, B. alexandrina proved to be a useful biomarker of nanomaterial contamination.

Biochemical, Histological Changes, Protein Electrophoretic Pattern, and Field Application of CuPb-Ferrite/TiO2 Nanocomposites for Controlling Terrestrial Gastropod Eobania vermiculata (Müller)

Eobania vermiculata is a hazardous snail that can damage ornamental plants and cause significant harm to plant sections in Egyptian areas. Herein, the molluscicidal activity of CuPb-Ferrite/TiO₂ and TiO₂ nanoparticles (NPs) against E. vermiculata was evaluated using the poisonous bait method. LC50 values were determined using the leaf dipping and contact methods, with values of 631.23 and 1703.49 ppm for CuPb-Ferrite/TiO₂ and 193.67 and 574.97 ppm for TiO₂. Exposure to both NPs resulted in a significant increase in the biochemical parameters of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP), as well as a decrease in total protein (TP) percentage of E. vermiculata. Histological examinations revealed that many digestive cells had ruptured, and their contents had been lost, while the foot's epithelial layer became ruptured. The average reduction was 66.36% for CuPb-Ferrite/TiO₂ NPs compared to the recommended molluscicide, Neomyl, with a 70.23% reduction in the field application. Electrophoretic separation of total protein using sodium dodecyl sulfate-polyacrylamide gel electrophoresis after treatment with LC50 concentrations of TiO₂ and CuPb-Ferrite/TiO₂ demonstrated the potency of these synthetic compounds as molluscicidal agents. Therefore, we recommend the use of CuPb-Ferrite/TiO₂ NPs as a novel land snail molluscicide because it is safe to use, and the baits are arranged to not affect irrigation water, with a high molluscicidal effect.

Histopathological, Immunohistochemical, Biochemical, and In Silico Molecular Docking Study of Fungal-Mediated Selenium Oxide Nanoparticles on Biomphalaria alexandrina (Ehrenberg, 1831) Snails

Daphnia magna and freshwater snails are used as delicate bioindicators of contaminated aquatic habitats. Due to their distinctive characteristics, selenium oxide nanoparticles (SeONPs) have received interest regarding their possible implications on aquatic environments. The current study attempted to investigate the probable mechanisms of fungal-mediated selenium nanoparticles' ecotoxicological effects on freshwater Biomphalaria alexandrina snails and Daphnia magna. SeONPs revealed a toxicological impact on D. magna, with a half-lethal concentration (LC₅₀) of 1.62 mg/L after 24 h and 1.08 mg/L after 48 h. Survival, fecundity, and reproductive rate were decreased in B. alexandrina snails exposed to SeONPs. Furthermore, the aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were markedly elevated, while albumin and total protein levels decreased. Histopathological damage in the hermaphrodite and digestive glands was detected by light, electron microscopy, and immunohistochemistry studies. The molecular docking study revealed interactions of selenium oxide with the ALT and AST. In conclusion, B. alexandrina snails and D. magna could be employed as bioindicators of selenium nanomaterial pollution in aquatic ecosystems. This study emphasizes the possible ecological effects of releasing SeONPs into aquatic habitats, which could serve as motivation for regulatory organizations to monitor and control the use and disposal of SeONPs in industry.

Using freshwater snail Biomphalaria glabrata (Say, 1818) as a biological model for ecotoxicology studies: a systematic review

Over time, a growing increase in human pollutants in the aquatic environment has been observed. The global presence of residues in water bodies reinforces the need to develop improved methods to detect them and evaluate their ecotoxicological effects in aquatic environments. Thus, this study aimed to present the main assays using Biomphalaria glabrata as a biological model for ecotoxicological studies. We performed a systematic literature review with data published up to June 2022 on the Web of Science, SCOPUS, Science Direct, PubMed, and SciELO databases. Thirty studies were selected for this review after screening. Biomphalaria glabrata has been studied as an ecotoxicological model for different substances through toxicity, embryotoxicity, cytotoxicity, genotoxicity, and bioaccumulation assays. Studies evaluating the impact of B. glabrata exposure to several substances have reported effects on their offspring, as well as toxicity and behavioral and reproductive effects. This review presents various assays using B. glabrata as a biological model for ecotoxicological studies. The use of a representative species of ecosystems from tropical regions is a necessary tool for tropical environmental monitoring. It was observed that the freshwater snail B. glabrata was effective for the evaluation of the ecotoxicity of several types of chemical substances, but further studies are needed to standardize the model.

Chronic and transgenerational effects of silver nanoparticles in freshwater gastropod Lymnaea stagnalis

Traditional ecotoxicological studies prove to be focused mainly on single-generation, multigenerational research in ecotoxicological testing is needed to improve the predictive approaches in ecological risk assessment. Silver nanoparticles (AgNPs) have been increasingly detected in aquatic environments due to their extensive use in consumer products. We investigated the transgenerational effects of AgNPs on the life traits of freshwater model gastropods Lymnaea stagnalis for two generations. The reversibility of the effects of using recovery experiments was also performed. Results showed that AgNPs induced high Ag bioaccumulation in the whole soft tissues of parental L. stagnalis after 21 days of exposure. The increased ROS production and reduced condition index and fecundity were found after exposure to AgNPs at 500 μg/L. These results highlight that under AgNPs exposure, adult gastropods might allocate more resources to resist oxidative stress rather than to growth or reproduction. Furthermore, the Ag accumulation and ROS production of egg clutches were significantly related to parental exposure duration and concentrations. On the other hand, isolated eggs exposure demonstrated biological effects were persistent in terms of the next generation. For example, after transfer to a clean medium, similar Ag bioaccumulation and ROS production were observed from eggs which parents were pre-exposed to 50 and 500 μg/L AgNPs. Current explicit consideration of offspring performance adds value to existing toxicity testing protocols. Parental exposure duration has important implications for offspring effects, and parental exposure can cause transgenerational changes in resistance that have significant implications for toxicity testing and adaptive responses. These effects across generations point out the need for multigenerational tests to assess the environmental risk of MNPs in aquatic organisms.

Embryonic exposure to selenium nanoparticles delays growth and hatching in the freshwater snail Lymnaea stagnalis

Selenium nanoparticles (SeNPs) have been applied in the biomedical and biocidal domain which may have potential environmental risks for aquatic systems. However, the knowledge of its toxicity and the role of functionalization on aquatic invertebrates are scarce. Thus, the present study aimed to analyze the embryotoxicity of two types of SeNPs coated with Sodium carboxymethyl cellulose (CMC-SeNPs) and Chitosan (CS-SeNPs) to the freshwater snail Lymnaea stagnalis in lake water, focusing on embryonic development. The influence of surface coatings and ions release, on the embryonic development of SeNPs to freshwater snail L. stagnalis was investigated. For this end, the snails were exposed to different concentrations of SeNPs and Se ions (0.05-1 mg L^-1) during 7 days and multiple endpoints were analyzed, including developmental stage frequency, morphological alterations, embryos mortality and hatching success. The results showed that both Se forms promoted the developmental delay, mortality, morphological changes, and hatching inhibition in snail embryos in a concentration-dependent manner. CMC-SeNPs are 2.6 times more embryotoxic compared to CS-SeNPs indicating the importance of surface coating on the embryotoxicity. Moreover, the results revealed that although both forms of Se inhibited the embryo development and reduced the hatching of L. stagnalis, the mode of action on the embryogenesis was different. SeNPs had a higher toxicity to snails' embryos compared to their dissolved counterparts. Despite significant dissolution, by comparing the SeNPs with their dissolved fraction, the results suggest SeNPs inhibition effect on the snail development could be caused by both SeNPs and Se⁴⁺, and SeNPs might be the major development retardation driver rather than Se ions. The present study evidenced by the first time the toxicity effects of SeNPs on the snail embryogenesis, and highlighted how SeNPs intrinsic properties influence their transformation and toxicity in environmental relevant scenarios.

Toxicity of plant-based silver nanoparticles to vectors and intermediate hosts: Historical review and trends

Green nanoparticles (GNPs), mainly green silver nanoparticles (Ag NPs), have been recommended as sustainable and eco-friendly technologies to control vectors and intermediate hosts. The aim of the current study is to carry out a historical and systematic literature review about the use of green plant-based Ag NPs (GP-Ag NPs) to control medically important mosquito, tick and gastropods. Data about the number of studies published per year, geographical distribution of studies (mailing address of the corresponding author), synthesis type (plant species, plant structure and extract types), physicochemical properties of GP-Ag NPs, experimental designs, developmental stages and the toxic effects on mosquitoes, ticks and gastropods were summarized and discussed. Revised data showed that GP-Ag NPs synthesis and toxicity in mosquitoes, ticks and snails depend on plant species, plant part, extract types, exposure condition and on the analyzed species. GP-Ag NPs induced mortality, tissue damage, biochemical and behavioral changes in mosquitoes and reduced their fecundity, oviposition, egg hatching and longevity. Ticks exposed to GP-Ag NPs presented increased mortality and reduced oviposition, while on snails, studies demonstrated mortality, oxidative stress, and DNA damage. Immune responses were also observed in snails after their exposure to GP-Ag NPs. GP-Ag NPs reduced the reproduction and population of several vectors and intermediate hosts. This finding confirms their potential to be used in gastropod control programs. Future studies about current gaps in knowledge are recommended.

Building the Bridge From Aquatic Nanotoxicology to Safety by Design Silver Nanoparticles

Nanotechnologies have rapidly grown, and they are considered the new industrial revolution. However, the augmented production and wide applications of engineered nanomaterials (ENMs) and nanoparticles (NPs) inevitably lead to environmental exposure with consequences on human and environmental health. Engineered nanomaterial and nanoparticle (ENM/P) effects on humans and the environment are complex and largely depend on the interplay between their peculiar properties such as size, shape, coating, surface charge, and degree of agglomeration or aggregation and those of the receiving media/body. These rebounds on ENM/P safety and newly developed concepts such as the safety by design are gaining importance in the field of sustainable nanotechnologies. This article aims to review the critical characteristics of the ENM/Ps that need to be addressed in the safe by design process to develop ENM/Ps with the ablility to reduce/minimize any potential toxicological risks for living beings associated with their exposure. Specifically, we focused on silver nanoparticles (AgNPs) due to an increasing number of nanoproducts containing AgNPs, as well as an increasing knowledge about these nanomaterials (NMs) and their effects. We review the ecotoxicological effects documented on freshwater and marine species that demonstrate the importance of the relationship between the ENM/P design and their biological outcomes in terms of environmental safety.

Emerging investigator series: metal nanoparticles in freshwater: transformation, bioavailability and effects on invertebrates

MNPs may undergo different environmental transformations in aquatic systems, consequently changing their mobility, bioavailability and toxicity to freshwater invertebrates.

Gonadal histopathology and inflammatory response in the freshwater snail exposed to iron oxide nanoparticles and ferric chloride: Insights into reproductive nanotoxicity

Considering that most animals in an aquatic ecosystem are invertebrates, concerns about the ecotoxicological impact of emerging pollutants, such as nanomaterials, in these populations are relevant, which can lead to loss of aquatic biodiversity. However, knowledge concerning the effects of iron-based nanoparticles (IONPs) at cell and tissue-levels on freshwater gastropods remains limited. Thus, the present study aimed to analyse the histopathological changes and inflammatory response in the freshwater snail Biomphalaria glabrata after chronic exposure to gluconic-acid functionalized IONPs (GLA-IONPs) in comparison with their dissolved counterpart (FeCl₃). Snails were exposed to both iron forms (1.0, 2.5, 6.25, and 15.62 mg L^-1) for 28 days, and the qualitative and quantitative histopathological assessment on hermaphrodite gonads was conducted, following by analysis of histopathological indices and inflammatory responses. Results showed that both iron forms (GLA-IONPs and FeCl₃) induced several gonadal histopathologies in the snails, mainly atresic acini, vacuolization of pre-vitellogenic oocytes, and atresic oocytes in a concentration-dependent pattern. GLA-IONPs induced a more intense inflammatory response and high frequency of vacuolized vitellogenic oocytes in comparison with FeCl₃. Environmentally relevant concentration (2.5 mg L^-1) of GLA-IONPs and FeCl₃ induced high gonadal histopathological indices, indicating their potential reproductive toxicity. The current study showed that the chronic exposure of snails to GLA-IONPs and their dissolved counterpart (FeCl₃) induced several gonadal histopathological changes and inflammatory responses in B. glabrata, confirming their potential risk to aquatic biodiversity.

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.

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.

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.