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Waste produced in homes is one of the main sources of pollutants in freshwater ecosystems. Therefore, it is imperative to implement methodologies that aid in environmental monitoring procedures. The use of organisms as biomonitors has grown increasingly prevalent as they are models that provide data that can be adequately evaluated. In this work, we investigated the genotoxic and cytotoxic effects caused by domestic sewage sludge through an analysis of biomarkers in the mollusk Biomphalaria glabrata. For the tests, increasing concentrations of 50, 100, 150, and 500 mg L -1 of domestic sewage sludge were standardized, in addition to control groups. Assays were performed after the mollusks were exposed to the domestic sewage sludge in acute (48 h) and chronic (15 d) manner. Toxicity tests were performed with embryonic and adult snails. The cytoplasmic and nuclear changes were analyzed in the hemocyte cells. Lastly, genotoxic damage was analyzed using the comet assay. Adult snails and embryos of B. glabrata showed no significant morphological changes. Domestic sludge caused deleterious effects on mollusks as confirmed after cell genotoxicity tests. Therefore, based on the results obtained from the analysis of B. glabrata hemocytes, we can affirm that domestic sewage sludge causes genotoxic and cytotoxic effects on mollusk cells. Therefore, it is possible to conclude that the mollusk Biomphalaria glabrata can be used as a good low-cost alternative to assist in the biomonitoring of freshwater environments. Graphical Abstract., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This research investigated the effect of the Croton rudolphianus leaf essential oil (EO) on Biomphalaria glabrata embryos (at different development stages) and adults, Schistosoma mansoni cercariae, and Artemia salina (non-target organism). It was possible to identify 31 compounds in the C. rudolphianus EO through GC-MS analysis. The major compounds from this oil were (E)-caryophyllene (17.33%), an unknown compound (16.87%), bicyclogermacrene (7.1%), δ-cadinene (6.62%) and germacrene D (5.38%). After incubation for 24 h, the EO of C. rudolphianus induced the occurrence of non-viable embryos (dead and malformed), with an LC 50 value of 126.54, 133.51, 143.53 and 161.95 µg/mL and an LC 90 value of 202.61, 216.48, 232.98 and 271.16 µg/mL to blastula, gastrula, trochophore and veliger embryonic stages, respectively. The EO was more effective against B. glabrata adults (LC 50 and LC 90  = 47.89 and 78.86 µg/mL, respectively), and S. mansoni cercariae (LC 50 and LC 90  = 14.81 and 22.15 after 120 mins of exposure, respectively) than against B. glabrata embryos. Concerning the micronucleus assay, the mean frequency of apoptosis, binucleation and micronucleus were 45.33 ± 3.51, 19.33 ± 1.53 and 0.67 ± 0.58 per 1000 cells at 25 µg/mL, which is the highest concentration tested. The oil killed A. salina with LC 50 and LC 90 values (68.33 and 111.5 µg/mL, respectively) higher than those determined for adult snails and S. mansoni cercariae. In conclusion, C. rudolphianus EO had a toxic effect against B. glabrata adults and embryos, and S. mansoni cercariae. Furthermore, this oil showed to be cytotoxic to hemocytes of B. glabrata. Concerning the non-target organism assay, C. rudolphianus EO was less toxic to A. salina then to adult snails and S. mansoni cercariae. Due to this, the EO from C. rudolphianus leaves is a potential alternative for schistosomiasis control., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Schistosomiasis is one of the most significant neglected tropical diseases, affecting around 260 million people worldwide, and Praziquantel is currently the only available drug for the treatment of infected persons. Thus, the search for new schistosomicidal compounds is urgent. The objective of this study was to investigate of the schistosomicidal effect of barbatic acid, a lichen metabolite, on adult worms of Schistosoma mansoni. The in vitro schistosomicidal effect was evaluated through the assessment of motility and mortality, cellular viability of the worms and ultrastructural analysis through scanning electron microscopy. To evaluate the cytotoxicity of barbatic acid, a cell viability assay was performed with human peripheral blood mononuclear cells. Barbatic acid showed a schistosomicidal effect after 3 h of exposure. At the end of 24 h the concentrations of 50-200 μM presented lethality on the worms. Motility changes were observed at sublethal concentrations. The IC 50 obtained by the cell viability assay for S. mansoni was 99.43 μM. Extensive damage to the worm's tegument was observed from 25 μM. No cytotoxicity was observed on human peripheral blood mononuclear cells. This report provides data showing the schistosomicidal effect of barbatic acid on S. mansoni, causing death, motility changes and ultrastructural damage to worms. In addition, barbatic acid was shown to be non-toxic to human peripheral blood mononuclear cells at concentrations that are effective against S. mansoni., Competing Interests: Declaration of Competing Interest All authors declare that there is no conflict of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Industrial development has provided numerous benefits to improve quality of life in modern times, however, it has also led to the development and use of a large number of toxic chemicals which have caused damage to various ecosystems. Consequently, knowledge of techniques and organisms that can be used to monitor, identify and quantify environmental pollutants has become increasingly relevant. Therefore, the objective of this study was to use the mollusk Biomphalaria glabrata to analyze biomarker and biomonitoring parameters of industrial sewage sludge. To perform the tests, concentrations of 50, 100, 150 and 500 mg L -1 of industrial sewage sludge were standardized. All the tests were performed after the animals were exposed to the sludge in acute and chronic forms. Embryos exposure to sludge did not show a significant percentage of the animals non-viable when compared to the control group. Subsequently, hemocytes were analyzed for the presence of cytoplasmic and nuclear alterations. Finally, the comet test was performed to quantify the genotoxic damage caused by exposure to industrial sludge. Analysis hemocytes showed a significant number of cellular alterations was observed, mainly due to the high frequency of apoptosis. Moreover, during the analysis of nucleoids several degrees of nuclear damage were identified, with the groups exposed to the highest concentrations presenting the greatest genotoxic damage. Thus, we can conclude that the parameters evaluated in the mollusk Biomphalaria glabrata have proven to be a good tool, along with other techniques and complementary organisms, to assist aspects related to biomonitoring of freshwater ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this study, the molluscicidal activities against Biomphalaria glabrata and cercaricidal activities against Schistosoma mansoni of the ether extract of Ramalina aspera were evaluated. Additionally, toxicity parameters were evaluated at sublethal doses in terms of the influence of the extract on the fertility and fecundity of snails, as well as morphological alterations and quantification of their immunological cells. A test with Artemia salina was also carried out, in order to verify the environmental toxicity of the compound. The ether extract of R. aspera, in which divaricatic acid was identified as the major compound, demonstrated molluscicidal activity at low concentrations against both embryos (LC 90 of 22.78, 24.23, 16.63 and 16.03 μg mL -1 for the gastrula, blastula, trochophore and veliger, respectively) and against adult snails (LC 90 of 8.66 μg mL -1 ), after 24 h of exposure. At the sublethal doses, it was possible to observe a decrease in fecundity and quantitative and morphological changes in the defense cells of the exposed snails. In addition, the extract of R. aspera showed a cercaricidal effect on S. mansoni from the concentration of 5.0 μg mL -1 , while showing low toxicity to Artemia salina. The ether extract of R. aspera demonstrated effective molluscicidal activity on embryos and adult snails of the species B. glabrata, cercariae of S. mansoni, and presenting low toxicity on Artemia salina. In this way, it could be considered a promising compound in the development of future molluscicidal and cercaricidal agents, thus helping to combat schistosomiasis., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Purpose: Some phytochemicals have shown the potential of being radiomodifiers, especially phenolic compounds, such as lichenic secondary metabolites. To evaluate the phytochemical usnic acid as a radiomodifier, embryonic cells of molluscs have been used due to their ease of collection, high sensitivity to physical and chemical agents, well-known embryology and low cost for analysis., Materials and Methods: This study aimed to assess the radiosensitizing action of usnic acid on Biomphalaria glabrata embryos. Samples were irradiated with 4 Gy of gamma rays from a 60 Co source (dose rate 2.906 Gy/h). An acute toxicity test was performed using B. glabrata embryos in the blastula stage, in order to determine the toxicity of usnic acid and to establish the lethal Concentration for 50% (LC 50 ). Subsequently, the radiomodifing capacity of usnic acid was estimated using assays with B. glabrata embryos., Results: Irradiation increased the number of non-viable embryos compared to unirradiated controls. Additionally, it was observed that embryos exposed to a non-toxic concentration of usnic acid (0.6 µg/mL) before irradiation showed a further enhancement in non-viable embryos when compared with exposure to ionizing radiation alone., Conclusion: The results presented here indicate that usnic acid makes cells more sensitive to the damaging effects of radiation.

In this study, the molluscicidal and antiparasitic activities of divaricatic acid was evaluated, targeting the mollusc Biomphalaria glabrata and cercariae of the helminth Schistosoma mansoni . Divaricatic acid showed high toxicity against both adult snails (5.5 μg/mL) and embryos (20 μg/mL after 6 h of exposure). Similar activity was observed in S. mansoni cercariae after only a short exposure time. The divaricatic acid proved to be a promising substance for the control of the snail B. glabrata , an intermediate host of schistosomiasis, as well as the cercariae of the pathogen.

In this study, the molluscicidal and antiparasitic activities of divaricatic acid was evaluated, targeting the mollusc Biomphalaria glabrata and cercariae of the helminth Schistosoma mansoni. In addition, the environmental toxicity of divaricatic acid was assessed by bioassay using the microcrustacean Artemia salina. Divaricatic acid showed high toxicity against both adult snails (5μg/mL) and embryos (20μg/mL after 6h of exposure). Similar activity was observed in Schistosoma mansoni cercariae after only a short exposure time (10μg/mL after 30min of exposure). The divaricatic acid did not show toxicity in the acute test using Artemia salina at concentrations equal to or below 200μg/mL. The divaricatic acid proved to be a promising substance for the elimination of the snail Biomphalaria glabrata, an intermediate host of schistosomiasis, as well as the cercariae of the pathogen, while being non-toxic to the Artemia salina at the same concentrations. This is the first experimental observation of the molluscicidal and cercaricide activity of divaricatic acid., (Copyright © 2017 Elsevier B.V. All rights reserved.)