Toxicological impact of oxyfluorfen 24% herbicide on the reproductive system, antioxidant enzymes, and endocrine disruption of Biomphalaria alexandrina (Ehrenberg, 1831) snails

Laevicaulis stuhlmanni slugs as accumulation bio-indicators of lead metal pollution: immunotoxic, physiological, and histopathological alterations

Trace metal pollution of soils is a widespread consequence of anthropogenic activity. Land slugs can be used as bio-indicators of the metals' pollution in the soil, so the present study aimed to determine the metal in the soil and Laevicaulis stuhlmanni land slug tissues by studying its effects on different physiological parameters. Slugs and soil samples were collected from fields in Abu-Rawash, Giza, Egypt. Slugs were identified, and the metals were determined in slug tissues and soil samples. On the other hand, slugs were reared in the laboratory and the new generation was fed on lettuce dipped in 0.027 µg/ml lead (Pb) for 10 days. The results revealed that the soil and slug tissues contained copper, manganese, lead, and zinc; the lead metal bioaccumulation factor was the highest. Also, the results showed that the hemocytes' count, testosterone, and estradiol hormones were significantly decreased. At the same time, the phagocytic index was increased considerably, and some morphological alterations in the granulocytes and hyalinocytes were observed after treatment with 0.027 µg/ml lead compared to untreated slugs. On the other hand, all the oxidative stress parameters were significantly increased in the treated slugs compared with the control. Concerning the histopathological studies, lead caused a rupture, vacuolation, or degeneration in the digestive cells of treated slugs. Finally, it can be concluded that the land slugs were sensitive to lead which was reflected by endocrine disruption, immunotoxicity, and increased oxidative stress parameters with histopathological damages. Hence, Laevicaulis stuhlmanni can be used as a metal accumulation bio-indicator to reflect the metal pollution in the soil.

Multi-biomarker approach to evaluate the toxicity of chlorpyrifos (active ingredient and a commercial formulation) on different stages of Biomphalaria straminea

Biomphalaria straminea is a freshwater gastropod native to South America and used in toxicological assessments. Our aim was to estimate 48 h-LC50 and sub-chronic effects after the exposure to low concentrations of chlorpyrifos as commercial formulation (CF) and active ingredient (AI) on B. straminea adult, embryos and juveniles. Concentrations between 1 and 5000 μg L-1 were chosen for acute exposures and 0.1 and 1 μg L-1 for the sub-chronic one. After 14 days biochemical parameters, viability and sub-populations of hemocytes, reproductive parameters, embryotoxicity and offspring' survival were studied. Egg masses laid between day 12 and 14 were separated to continue the exposure and the embryos were examined daily. Offspring' survival and morphological changes were registered for 14 days after hatching. 48 h-LC50, NOEC and LOEC were similar between CF and AI, however the CF caused more sub-lethal effects. CF but not the AI decreased carboxylesterases, catalase and the proportion of hyalinocytes with respect to the total hemocytes, and increased superoxide dismutase and the % of granulocytes with pseudopods. Also CF caused embryotoxicity probably due to the increase of embryos' membrane permeability. Acetylcholinesterase, superoxide dismutase, hemocytes sub-populations, the time and rate of hatching and juveniles' survival were the most sensitive biomarkers. We emphasize the importance of the assessment of a battery of biomarkers as a useful tool for toxicity studies including reproduction parameters and immunological responses. Also, we highlight the relevance of incorporating the evaluation of formulations in order to not underestimate the effects of pesticides on the environment.

Temperature influence on the sensitivity of Artemia franciscana to globally used pesticides - Oxyfluorfen and copper

Climate change further the world's human population increase is a mainstream political issue, and it's critical to search for solutions to produce enough food to feed everyone. Pesticides and fertilizers have been used as an easy solution to prevent pests and increase food production. Nevertheless, their overuse has dangerous effects on the ecosystems and communities. Oxyfluorfen (Oxy) and copper (Cu) based formulations are used as pesticides and widely applied on agricultural fields for crop protection. However, they have shown negative effects on non-target species. So, this work proposes to: a)determine the lethal concentration of Oxy and Cu to the zooplankton, Artemia franciscana, at different temperatures (15 °C, 20 °C and 25 °C); b)understand the biochemical impacts of these chemicals at the different temperatures scenarios, on A. franciscana and c)evaluate the impact of the climate changes, particularly the temperature increase, on this species sensitivity to the tested pesticides. Acute and sub-lethal bioassays with Oxy and Cu were performed at different temperatures to determine the lethal concentration of each chemical and to understand the effects of the compounds at different temperatures on the biochemical profiles of A. franciscana. Results showed an increase in chemicals toxicity with the temperature, and Oxy was revealed to be more noxious to A. franciscana than Cu; at a biochemical level, significant differences were observed among temperatures, with the biggest differences between the organisms exposed to 15 °C and 25 °C. Overall, a decrease in fatty acids (FA) and sugars was observed with the increase in Cu and oxyfluorfen concentrations. Different trends were observed with temperature increase, with FA increase in the organisms exposed to Cu and the opposite was observed in the ones exposed to oxyfluorfen. Sugar content decreases in the organisms exposed to oxyfluorfen with temperature increase and showed a non-linear behaviour in the ones exposed to Control and Cu treatments.

Phyto-synthesized silver nanoparticles from Sargassum subrepandum: anticancer, antimicrobial, and molluscicidal activities

In the realm of nanotechnology, the use of algae to produce nanoparticles is an environmentally friendly, sustainable, and economically viable strategy. In the present study, the brown macroalgae Sargassum subrepandum was utilized to effectively produce silver nanoparticles (AgNPs). Through various characterization techniques, the AgNPs' structural integrity was confirmed. AgNPs exhibited significant antimicrobial activity against Pseudomonas aeruginosa and Fusarium equiseti. AgNPs showed cytotoxic effects on the MCF-7 breast adenocarcinoma cell line with an IC50 of 12.5 µg/ml. Treatment with AgNPs resulted in a marked reduction in cell viability, alongside evident apoptotic and necrotic morphological changes in the cancer cells. Through molecular docking studies, a deeper understanding of the interaction between AgNPs and crucial proteins related to cancer has been achieved, AgNPs showed a promising molluscicidal action on Biomphalaria alexandrina snails, a Schistosoma mansoni intermediate host. The half-lethal dose (LC50) of AgNPs was determined to be 0.84 mg/L. The potential consequences of its administration include potential disruptions to the glycolysis profile, as well as potential impacts on the steroidal hormone's estrogen and testosterone and certain kidney function tests. This study highlights the diverse uses of algae-synthesized AgNPs, ranging from healthcare to environmental management, demonstrating their importance in advancing nano-biotechnological solutions.

Repurposing the drug, amprolium as a novel molluscicide against the land snail (Eobania vermiculata)

Amprolium (AMP) is an organic compound used as a poultry anticoccidiostat. The aim of this work is to repurpose AMP to control the land snail, Eobania vermiculata in the laboratory and in the field. When snails treated with ½ LC₅₀ of AMP, the levels of alkaline phosphatase (ALP), total lipids (TL), urea, creatinine, malondialdehyde (MDA), catalase (CAT), and nitric oxide (NO) were significantly increased, whereas the levels of acetylcholinesterase (AChE), total protein (TP), and glutathione (GSH) decreased. It also induced histopathological and ultrastructural changes in the digestive gland, hermaphrodite gland, kidney, mucus gland, and cerebral ganglion. Furthermore, scanning electron micrographs revealed various damages in the tegumental structures of the mantle-foot region of E. vermiculata snails. The field application demonstrated that the AMP spray caused reduced percentages in snail population of 75 and 84% after 7 and 14 days of treatment. In conclusion, because AMP disrupts the biology and physiology of the land snail, E. vermiculata, it can be used as an effective molluscicide.

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.

Biological, biochemical and genotoxicological alterations of Benzylamine on Biomphalaria alexandrina snails and its Schistosoma mansoni larvicidal potential

Biomphalaria spp. snails are freshwater gastropods that responsible for Schistosoma mansoni transmission. Schistosomiasis is a chronic illness that occurred in underdeveloped regions with poor sanitation. The aim of the present study is to evaluate the molluscicidal activity of benzylamine against B. alexandrina snails and it larvicidal effects on the free larval stages of S. mansoni. Results showed that benzylamine has molluscicidal activity against adult B. alexandrina snails after 24 h of exposure with median lethal concentration (LC50) 85.7 mg/L. The present results indicated the exposure of B. alexandrina snails to LC10 or LC25 of benzylamine resulted in significant decreases in the survival, fecundity (eggs/snail/week) and reproductive rates, acetylcholinesterase, albumin, protein, uric acid and creatinine concentrations, levels of Testosterone (T) and 17β Estradiol (E), while alkaline phosphatase levels were significantly increased in comparison with control ones. The present results showed that the sub lethal concentration LC50 (85.7 mg/L) of benzylamine has miracidial and cercaricidal activities, where the Lethal Time (LT50) for miracidiae was 17.08 min while for cercariae was 30.6 min. Also, results showed that were decreased significantly after exposure to sub lethal concentrations compared with control. The present results showed that the expression level of NADH dehydrogenase subunit 1 (ND1) genes and cytochrome oxidase subunit I (COI) in B. alexandrina snails exposed to LC10 or LC25 concentrations benzylamine were significantly decreased compared to the control groups. Therefore, benzylamine could be used as effective molluscicide to control schistosomiasis.

Toxicity of two pesticides in binary mixture on survival and enzymatic response of Cerastoderma edule - The warming influence

Pesticide application increased by about 1 million tonnes in the last 3 decades. Pesticides' overuse, coupled with the need for several pesticides to control different pests in the same crop, and its application many times per year, results in dangerous chemical cocktails that enter in aquatic systems, with impacts to the ecosystems and its communities. Climatic changes are currently another great concern, is predicted by the end of the 21st century, the earth's surface temperature will increase by about 4 °C. Bivalve species are reported as essential to the ecosystems' balance. However, they are also indicated as the organisms that will suffer the most serious effects of the temperature increase. So, this work intends to: a) verify the harm of the sub-lethal concentrations of two worldwide used pesticides, oxyfluorfen and copper (Cu), when combined, to Cerastoderma edule at 15 °C and 20 °C; b) assess the changes in the antioxidant defence system, the activity of the neurological enzyme acetylcholinesterase and the nutritive value of C. edule, after exposure to sub-lethal concentrations of oxyfluorfen and Cu, single and in the mixture, at 15 °C and 20 °C; c) observe the interaction between Cu and oxyfluorfen, considering the different biomarkers. Bivalves were exposed to oxyfluorfen and Cu, single and combined, for 96 h, at 15 °C and 20 °C. Results showed lethal effects to the organisms exposed at 20 °C when exposed to the highest binary mixture concentrations. Biochemical effects were observed on the organisms exposed to 15 °C, despite not observing any lethal effects. Briefly, there was a reported increase in oxidative stress and a decrease in protein content, regardless of the increase in the activity of antioxidant enzymes. These results suggest the potentially dangerous effects of the chemicals' mixture combined with the temperature, on this species and its consumers, impacting the trophic chain, and consequently, the community structure and function.

Molluscicidal activity of calcium borate nanoparticles with kodom ball-flower structure on hematological, histological and biochemical parameters of Eobania vermiculata snails

Land snails are the most harmful pests in agricultural fields. Eobania vermiculata is a widespread snail species that causes massive damage to all agricultural crops. Thus, the molluscicidal activity of calcium borate nanoparticles (CB-NPs) against Eobania vermiculata was evaluated and compared with metaldehyde (Gastrotox® E 5% G). The amorphous phase of CB-NPs was obtained after thermal treatment at a low temperature (500 °C) which conformed by X-ray diffraction (XRD) analysis. CB-NPs are composed of aggregated nano-sheets with an average thickness of 54 nm which enhanced their molluscicidal activity. These nano-sheets displayed meso-porous network architecture with pore diameters of 13.65 nm, and a 9.46 m2/g specific surface area. CB-NPs and metaldehyde (Gastrotox® E 5% G) exhibited molluscicidal effects on Eobania vermiculata snails with median lethal concentrations LC50 of 175.3 and 60.5 mg/l, respectively, after 72 h of exposure. The results also showed significant reductions of Eobania vermiculata snails hemocytes' mean total number, the levels of Testosterone (T) and Estrogen (E), alkaline phosphatase, acid phosphatase, albumin, and protein concentrations, succinate dehydrogenase, glucose, triglycerides and phospholipids levels, while significant increases in the phagocytic index and mortality index, both transaminases (ALT and AST) and glycogen phosphorylase concentration were observed after the exposure to LC50 of CB-NPs or metaldehyde (Gastrotox® E 5% G) compared to the control group. Therefore, CB-NPs could be used as an alternative molluscicide for controlling Eobania vermiculata, but further studies are needed to assess their effects on non-target organisms.

Biomonitoring of manganese metal pollution in water and its impacts on biological activities of Biomphalaria alexandrina snail and larvicidal potencies

Metal pollution has many dangerous environmental and human health consequences due to the bioaccumulation in the tissues. The present study aims to measure the bioaccumulation factor of the manganese (Mn) heavy metal in Biomphalaria alexandrina snails' tissues and water samples. The current results showed the concentration of Mn heavy metal in water (87.5 mg/l) and its bioaccumulation factor in Helisoma duryi tissue was higher than that in tissues of Physa acuta and B. alexandrina snails. Results showed that 87.5 mg/l Mn concentration had miracidicidal and cercaricidal activities. Also, this concentration decreased the mean total number of the hemocytes after exposure for 24 h or 48 h, while increasing both the mean mortality and phagocytic indices of the hemocytes of exposed snails. It caused alterations in the cytomorphology of the hemocytes of exposed snails after 24 or 48 h, where the granulocytes had irregular cell membranes and formed pseudopodia. Besides, levels of testosterone (T) and estradiol (E) were increased after exposure to 87.5 mg/l Mn metal compared to the control group. Also, it increased MDA (malonaldehyde) and TAC (total antioxidant capacity) contents, while decreasing SOD (superoxide dismutase). Besides, it caused significant histopathological damages in both hermaphrodite and digestive glands, represented in the degeneration of the gonadal, digestive, secretory cells, and the connective tissues. Therefore, B. alexandrina might be used as a sensitive bioindicator of pollution with Mn heavy metal to avoid ethics rules; besides, they are readily available and large in number.

Effects of Inorganic and Organic Pollutants on the Biomarkers' Response of Cerastoderma edule under Temperature Scenarios

Currently, there is increased chemical pollution, and climate change is a major concern to scientific, political and social communities globally. Marine systems are very susceptible to changes, and considering the ecological and economic roles of bivalve species, like Cerastoderma edule, studies evaluating the effects of both stressors are of great importance. This study intends to (a) determine the toxicity of copper (Cu) and oxyfluorfen at the lethal level, considering the temperature; (b) assess the changes in the antioxidant defence enzymes as a consequence of the simultaneous exposure to chemical and warming pressures; and (c) determine if lipid peroxidation (LPO) and neurotoxic effects occur after the exposure to chemical and temperature stressors. C. edule was exposed to Cu and oxyfluorfen at different temperatures (15 °C, 20 °C and 25 °C) for 96 h. The ecotoxicological results reveal a higher tolerance of C. edule to oxyfluorfen than to Cu, regardless of the temperature. The antioxidant defence system revealed efficiency in fighting the chemicals' action, with no significant changes in the thiobarbituric reactive species (TBARS) levels to 15 °C and 20 °C. However, a significant inhibition of acetylcholinesterase (AChE) was observed on the organisms exposed to oxyfluorfen at 20 °C, as well as a decreasing trend on the ones exposed to Cu at this temperature. Moreover, the catalase (CAT) showed a significant increase in the organisms exposed to the two highest concentrations of Cu at 15 °C and in the ones exposed to the highest concentration of oxyfluorfen at 20 °C. Looking at the temperature as a single stressor, the organisms exposed to 25 °C revealed a significant increase in the TBARS level, suggesting potential LPO and explaining the great mortality at this condition.

Toxicological, hepato-renal, endocrine disruption, oxidative stress and immunohistopathological responses of chitosan capped gold nanocomposite on Biomphalaria alexandrina snails

The present investigation aimed to synthesize chitosan‑gold nanocomposites (Ch-AuNPs) with gamma radiation, then to evaluate its toxic effect on the freshwater snails Biomphalaia alexandrina. Results showed that Ch-AuNPs is spherical shaped with average size 12 nm. It had a toxic effect against B. alexandrina snails with LC50 20.43 mg/l. Exposure of B. alexandrina snails to LC10 7.51 or LC25 13.63 mg/l of Ch-AuNPs, reduced the survival, reproductive and fecundity rates; total protein and albumin; both testosterone (T) and 17β Estradiol (E) levels; SOD and CAT activities of exposed snails while increased the activities of transaminases (AST & ALT), uric acid, creatinine, TAC and MDA levels compared to the control group. Results were supported by histopathological and immunohistopathological alterations of the digestive and hermaphrodite glands. In conclusion B. alexandrina could be used as a model to screen the negative impact of nanomaterials. Also, Ch-AuNPs could be used as a molluscicidal agent.

Bisphenol A effects on the host Biomphalaria alexandrina and its parasite Schistosoma mansoni

Bisphenol A (BPA) is one of the most potent endocrine-disrupting chemicals (EDCs) that adversely affect aquatic organisms. The present investigation explored the effects of exposure to BPA at 0.1 and 1 mgL-1 concentrations on the fecundity of Biomphalaria alexandrina, snail's infection with Schistosoma mansoni, and histology of the ovotestis and topographical structure of S. mansoni cercariae emerged from exposed snails. The 24 h LC50 and LC90 values of BPA against B. alexandrina were 8.31 and 10.88 mgL-1 BPA, respectively. The exposure of snails to 0.1 or 1 mgL-1 BPA did not affect the snail's survival. However, these concentrations caused an increase in the reproductive rate (Ro) of infected snails. A slight decrease in egg production was observed in snails exposed to 0.1 mgL-1 BPA after being infected (infected then exposed). However, a significant increase in egg production was noted in snails exposed to 1 mgL-1 BPA after infection with S. mansoni. Histopathological investigations indicated a clear alteration in the ovotestis tissue structure of exposed and infected-exposed groups compared to the control snails. Chronic exposure to BPA caused pathological alterations in the gametogenic cells. SEM preparations of S. mansoni cercariae emerged from infected-exposed snails showed obvious body malformations. From a public health perspective, BPA pollution may negatively impact schistosomiasis transmission, as indicated by the disturbance in cercarial production and morphology. However, it has adverse effects on the reproduction and architecture of reproductive organs of exposed snails, indicating that B. alexandrina snails are sensitive to sublethal BPA exposure.

Ecotoxicological and biochemical effects of a binary mixture of pesticides on the marine diatom Thalassiosira weissflogii in a scenario of global warming

Under the current scenario of global warming, it is ecologically relevant to understand how increased temperature influences the combined toxicity of pesticides to aquatic species. Hence, this work aims to: a) determine the temperature effect (15 °C, 20 °C and 25 °C) on the toxicity of two pesticides (oxyfluorfen and Copper (Cu)), on the growth of Thalassiosira weissflogii; b) assess whether temperature affects the type of toxicity interaction between these chemicals; and c) assess the temperature effect on biochemical responses (fatty acids (FA) and sugar profiles) of the pesticides on T. weissflogii. Temperature increased the tolerance of the diatoms to the pesticides with EC₅₀ values between 3.176 and 9.929 μg L^-1 for oxyfluorfen and 42.50-230.75 μg L^-1 for Cu, respectively, at 15 °C and 25 °C. The mixtures toxicity was better described by the IA model, but temperature altered the type of deviation from dose ratio (15 °C and 20 °C) to antagonism (25 °C). Temperature, as well as the pesticide concentrations, affected the FA and sugar profiles. Increased temperature increased saturated FA and decreased unsaturated FA; it also affected the sugar profiles with a pronounced minimum at 20 °C. Results highlight effects on the nutritional value of these diatoms, with potential repercussion on food webs.

Leaching of herbicides mixtures from pre-exposed agricultural plastics severely impact microalgae

Farmlands represent a source of aged plastics and pesticides to the surrounding environments. It has been shown that chemicals can be sorbed and desorbed from plastics, but the interaction between plastic and mixtures of pesticides and their effects on freshwater biota has not been assessed yet. The aim of the work was to assess the potential role of agricultural plastics as vectors for a mixture of two herbicides and the impact of the herbicide mixture lixiviated from them towards the freshwater microalga Chlamydomonas reinhardtii. Pristine and aged polyethylene plastics collected from agricultural areas were exposed to the herbicides, bifenox, oxyfluorfen and their mixtures. The microalgae were exposed for 72 h to the leachates desorbed from plastics and the effect was quantified in terms of total chlorophyll content and several physiological parameters assessed by flow cytometry. Our results showed that changes in physicochemical properties (hydroxyl and carbonyl index, hydrophobicity, texture) in aged plastics increased their capacity to retain and to desorb the herbicides. Microalgae exposed to leachates containing bifenox, oxyfluorfen, or their mixture showed reactive oxygen species overproduction, lipid peroxidation, membrane potential hyperpolarization, intracellular pH acidification, and a loss of metabolic activity. The toxicological interactions of the leachate mixture were assessed using the Combination Index (CI)-isobologram method showing antagonism at low effect levels turning to synergism when the effect increased. In this work, we proved the hypothesis that ageing increases the capacity of agricultural plastics to behave as vector for toxic chemicals to the biota.

Oxyfluorfen induces cell cycle arrest by regulating MAPK, PI3K and autophagy in ruminant immortalized mammary epithelial cells

Oxyfluorfen, a phenoxy phenyl-type herbicide, causes significant damage to ecosystems through chronically effecting invertebrates, fish, and mammals. Considering its adverse effect on ecosystem conservation, it is necessary to investigate its toxic effects on animals. However, the mechanisms of oxyfluorfen toxicity on bovines are not well established. This study investigated the cytotoxic effect of oxyfluorfen on bovine mammary epithelial cells (MAC-T). We conducted several functional experiments to examine the response of MAC-T to oxyfluorfen under various concentrations (0, 1, 2, 5, and 10 ppm). Oxyfluorfen decreased cell viability and increased apoptotic cells by regulating the expression of apoptotic genes and proteins in MAC-T. In addition, oxyfluorfen-treated cells exhibited reduced PCNA expression with a low 3D spheroid formation as compared to that of control cells. Furthermore, oxyfluorfen treatment suppressed cell cycle progression with a decrease in cyclin D1 and cyclin A2 in MAC-T. Next, we performed western blot analysis to verify intercellular signaling changes in oxyfluorfen-treated MAC-T. The phosphor-AKT protein was increased, whereas MAPK signal pathways were decreased. Particularly, the combination of oxyfluorfen with U0126 or SP600125 completely blocked the ERK1/2 and JNK pathways leading to cell viability in MAC-T. Moreover, oxyfluorfen induced inflammatory gene expression and autophagy by increasing phosphorylation of P62 and LC3B in MAC-T. These results demonstrated that oxyfluorfen has cytotoxic effect on MAC-T, implying that the milk production capacity in cows may eventually harm humans.

Exposure to oxyfluorfen-induced hematobiochemical alterations, oxidative stress, genotoxicity, and disruption of sex hormones in male African catfish and the potential to confront by Chlorella vulgaris

The present study evaluated the effect of chronic exposure to oxyfluorfen (OXY) on different physiological responses of male African catfish, Clarias gariepinus, and the ameliorative effect of Chlorella vulgaris. The fish (160 ± 5.10 g) were exposed to 1/20 LC₅₀ of OXY (0.58 mg/L) for 60 consecutive days with or without co-administration of C. vulgaris (25 g/kg diet) in triplicate groups. The results revealed that chronic exposure to a sublethal level of OXY induced severe anemia and leukopenia. OXY-exposed fish experienced hypoproteinemia, marked lower AchE levels, and a significant increase in glucose, liver, and kidney function biomarkers. The DNA fragmentation of the liver increased by 15 % in fish compared to the control. On the other hand, lipid peroxidation, superoxide dismutase, and catalase activities were markedly increased in the liver and testes homogenates of the OXY-exposed fish. Meanwhile, total antioxidant capacity and glutathione S-transferase levels declined in the same tissues. Exposure to OXY induced a significant reduction in testosterone and luteinizing hormone levels and a significant increase in follicle stimulating hormone and estradiol. Meanwhile, C. vulgaris dietary supplementation succeeded in alleviating the negative impact of OXY on hematobiochemical parameters and restoring the antioxidant balance in the liver and testes. Furthermore, it ameliorated endocrine disruption and repaired sex hormone levels. In conclusion, exposure to OXY could induce systemic stress, oxidative stress, and endocrine disruption in male C. gariepinus. The dietary supplementation of C. vulgaris could be a potential protective strategy against the toxicity of OXY.

Toxicological effects of Saponin on the free larval stages of Schistosoma mansoni, infection rate, some biochemical and molecular parameters of Biomphalaria alexandrina snails

Saponins have been used as biopesticides. The objective of the present study is to investigate the toxic effects of Saponin against Biomphalaria alexandrina snails. Results showed that Saponin exhibited a molluscicidal activity against adult B. alexandrina snails at LC₅₀ (70.05 mg/l) and had a larvicidal effect on the free larval stages of Schistosoma mansoni. To evaluate the lethal effects, snails were exposed to either LC₁₀ (51.8 mg/l) or LC₂₅ (60.4 mg/l) concentrations of Saponin. The survival, the infection rates, protein, albumin, and total fat levels were decreased, while glucose levels were increased in exposed snails compared to control snails. Also, these concentrations significantly raised Malondialdehyde (MDA) and Glutathione S Transferase (GST) levels, whereas reduced Superoxide dismutase (SOD) activity and the total antioxidant capacity (TAC) in exposed snails. Furthermore, these concentrations resulted in endocrine disruptions where it caused a significant increase in testosterone (T) level; while a significant decrease in Estradiol (E2) levels were noticed. As for Estrogen (E) level, it was increased after exposure to LC₁₀ Saponin concentration while after exposure to LC₂₅ concentration, it was decreased. Also, LC₁₀ and LC₂₅ concentrations of Saponin caused a genotoxic effect and down-regulation of metabolic cycles in the snails. In conclusion, Saponins caused deleterious effects on the intermediate host of schistosomiasis mansoni. Therefore, B. alexandrina snails could be used as models to screen the toxic effects of Saponins in the aquatic environment and if it was used as a molluscicide, it should be used cautiously and under controlled circumstances.

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.

The Lethal and Sub-Lethal Effects of Fluorinated and Copper-Based Pesticides-A Review

In recent decades, pollution levels have increased, mainly as a result of the intensive anthropogenic activities such industrial development, intensive agricultural practices, among others. The impact of metals and organic contaminants is, nowadays, a great concern to the scientific and political communities. Copper compounds are the main sold pesticides in Europe, as well as herbicides, including glyphosate. Diphenyl ethers are the second ones most sold. Glyphosate and copper compounds are intensively studied, but the opposite is seen in the case of diphenyl ethers, including fluorinated pesticides (e.g., oxyfluorfen). Some research has been performed to increase the knowledge about these contaminants, daily inputted on the aquatic systems and with dangerous effects at physical and biochemical levels on the organisms. A wide range of biomarkers (e.g., growth, survival, reproductive success, enzymatic activity, lipid metabolism) has been applied to determine the potential effects in many species. This review intends to: (a) perform a compilation of the knowledge in previous research about the action mode of organic (fluorinated-based herbicide) and inorganic (copper-based pesticides) contaminants; (b) carry out an information survey about the lethal and sub-lethal effects of the fluorinated-based pesticides, namely the oxyfluorfen and the copper-based pesticides, on aquatic species from different trophic levels, according to in vitro and in vivo studies; (c) understand the impact of oxyfluorfen and copper-based pesticides, considering their effects reported in in vitro studies and, simultaneously, the authorized concentrations by legal organizations and the effective concentrations of each pollutant found in the environment. The literature analyzed revealed noxious effects of Cu and oxyfluorfen to aquatic organisms, including freshwater and marine species, even when exposed to the reference as well as to environmental concentrations, thus highlighting the importance of more monitoring and ecotoxicological studies, to chemical pollutants and different species from different ecological niches, to sustain and improve the legislation.

Effect of Eucalyptus globulus oil and Ricinus communis methanolic extract as potential natural molluscicides on the reproductive biology and some antioxidant enzymes of the land snail, Theba pisana

This study was conducted to investigate the effects of Eucalyptus globulus oil and methanolic extract of Ricinus communis seeds on the reproductive biology of the land snail Theba pisana. For this purpose, the snails were exposed to different concentrations of these plant extracts for six weeks. Rates of oviposition, hatching percentages, reproductive hormones and the histological structures of the hermaphrodite gland were estimated. Antioxidant enzymes were also estimated. The obtained results revealed that all tested concentrations of both tested natural products exerted hazardous effects on exposed snails. The mean egg number/snail treated with 2% E. globulus and R. communis were significantly decreased to 22 and 14 eggs respectively compared to 79 eggs for control. The hatching rates were dramatically decreased with increasing concentrations of both products. 2% of R. communis extract caused highly significant decrease in the activities of CAT, SOD, GST and MDA antioxidant enzymes while the same concentration of Eucalyptus oil resulted in elevations of CAT and SOD activities and significantly decreased GST and MDA activities. Levels of reproductive hormones were greatly disrupted and the histological structures of hermaphrodite acini as well as various developmental stages of spermatogenesis and oogenesis of treated snails were strictly spoiled.

Molluscicidal and biochemical effects of green-synthesized F-doped ZnO nanoparticles against land snail Monacha cartusiana under laboratory and field conditions

The glass clover snail, Monacha cartusiana (M. cartusiana) is one of the most seriously impacting economic animal pests spreading across Egypt which inflicts severe damages to the agriculture. A green route is developed by deploying an abundant Rosemary plant leaves aqueous extract to synthesize ZnO and F-doped ZnO (F-ZnO) nanoparticles (NPs) that display high molluscicidal activities against the M. cartusiana land snails via leaf dipping and contact techniques. The effect of lethal concentrations, that kills 50% of exposed snails (LC50) value of the treatments, is examined on the activity of alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), enzymes, total protein (TP), total lipids (TL) and cholesterol level of snails, including the histopathological evaluation of the digestive gland and foot of M. Cartusiana. Their molluscicidal activity as poisonous baits under field conditions is also evaluated and compared to the recommended molluscicide, Neomyl. The results show that F^- doping dramatically improves the snail control capability of ZnO NPs, and promotes a considerable increase in both ALT and AST enzymes with an enhancement of TL and Cholesterol levels, but a significant decrease in TP content and ALP activity in treated snails compared to the control group. The LC₅₀ values are found to be 1381.55 and 2197.59 ppm using the leaf dipping for F-ZnO and ZnO, while 237.51 and 245.90 ppm can be achieved using the contact technique, respectively. The greenly synthesized F-ZnO and ZnO NPs induce severe histological alterations in the digestive gland and foot of M. cartusiana, including a complete destruction of the digestive tubules. The histological evaluation of the foot of M. cartusiana exposed to ZnO, shows a rupture of the epithelial layer of the foot sole, while F- ZnO NPs causes the folds of the foot becoming deeper and the rupture of epithelial layer. Our field experiments further demonstrate that F-ZnO achieves 60.08% reduction, while ZnO attains 56.39% diminution in snail population compared to the commercial, Neomyl (69.55%), exhibiting great potentials in controlling the harmful land snail populations.

Toxicological impact of organophosphorus Chlorpyrifos 48%EC pesticide on hemocytes, biochemical disruption, and molecular changes in Biomphalaria alexandrina snails

Organophosphorus pesticides like Chlorpyrifos 48%EC were widely used to control agricultural pests. The present study aimed to evaluate the toxic effects of Chlorpyrifos 48%EC on B. alexandrina snails, the intermediate host of Schistosoma mansoni. After exposure of snails to serial concentrations to determine the LC₅₀, thirty snails for each sublethal concentration (LC₁₀ 2.1 and LC₂₅ 5.6 mg/l) in each group were exposed for 24 h followed by another 24 h for recovery. After recovery random samples were collected from hemolymph and tissue to measure the impacts on Phagocytic index, histological, biochemical, and molecular parameters. The current results showed a toxic effect of Chlorpyrifos 48%EC on adult B. alexandrina snails after 24 h of exposure at LC₅₀ 9.6 mg/l. After exposure to the sub-lethal concentrations of this pesticide, it decreased the total number of hemocytes and the percentage of small cells, while increased the percentage of hyalinocytes. The granulocyte percentage was increased after exposure to LC₁₀, while after LC₂₅, it was decreased compared to the control group. Also, the light microscopical examination showed that some granulocytes have plenty of granules, vacuoles and filopodia. Some hyalinocytes were contained shrinked nuclei, incomplete cell division and forming pseudopodia. Besides, the phagocytic index of hemocytes was significantly increased than control in all treated groups. Also, these sub-lethal concentrations increased MDA and SOD activities, while, tissue NO, GST and TAC contents were significantly decreased after exposure. Levels of Testosterone (T) and Estradiol (E) were increased significantly after exposure compared with control group. The present results showed that the concentration of DNA and RNA was highly decreased after exposure to LC₁₀, ₂₅ than the control group. Therefore, B. alexandrina snails could be used as a bio monitor of the chemical pollution. Besides, this pesticide could reduce the transmission of schistosomiasis as it altered the biological system of these snails.

Immunotoxical, neurotoxical, histopathological and immunohistopathological alterations of Nerium oleander and Tecoma stans methanolic extract on Biomphalaria alexandrina snails

Schistosomiasis is a severe illness that caused socioeconomic problems. The present study aimed to investigate the molluscicidal activities of the methanolic extract of Nerium oleander and Tecoma stans on B. alexandrina snails. The present results showed that N. oleander had the higher molluscicidal effect (LC₅₀: 138.6 mg/l) than T. stans methanolic extract (LC₅₀: 256.0 mg/l). These concentrations had no mortality effects on Daphnia magna during the first 12 h of the exposure, while, they had a cercaricidal activity. Exposure of B. alexandrina snails to the sub lethal concentrations (LC₁₀ and LC₂₅) of the methanolic extract of either N. oleander or T. stans caused a concentration- dependent significant decrease in their mean total number of hemocyte and hyalinocytes percent, while, both the round small and the granulocytes were increased than the control group. Exposure of B. alexandrina snails to LC₂₅ of the methanolic extract of N. oleander or T. stans, caused morphological alterations in the hemocytes that were studied by both light and electron microscopy. The sub lethal concentration (LC₂₅) significantly decreased the acetyl cholinesterase activities, acid and alkaline phosphatase levels and the protein content. Histopathological changes occurred in the digestive and the hermaphrodite glands of exposed B. alexandrina snails to LC₂₅ of the methanolic extracts. These alterations were confirmed by Immunohistochemistry for PCNA and Cyclin D1 expressions. Conclusively, these plants could be used to decrease the spread of schistosomiasis as they are cheap and environmentally safe to replace the synthetic molluscicides for snail control.

Myco-Synthesized Molluscicidal and Larvicidal Selenium Nanoparticles: A New Strategy to Control Biomphalaria alexandrina Snails and Larvae of Schistosoma mansoni with an In Silico Study on Induced Oxidative Stress

Schistosomiasis is a tropical disease with socioeconomic problems. The goal of this study was to determine the influence of myco-synthesized nano-selenium (SeNPs) as a molluscicide on Biomphlaria alexandrina snails, with the goal of reducing disease spread via non-toxic routes. In this study, Penicillium chrysogenum culture filtrate metabolites were used as a reductant for selenium ions to form nano-selenium. The SeNPs were characterized via UV-Vis spectrophotometer, Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). Myco-synthesized SeNPs had a significant molluscicidal effect on B. alexandrina snails after 96 h of exposure at a concentration of 5.96 mg/L. SeNPs also had miracidicidal and cercaricidal properties against S. mansoni. Some alterations were observed in the hemocytes of snails exposed to SeNPs, including the formation of pseudopodia and an increasing number of granules. Furthermore, lipid peroxide, nitric oxide (NO), malondialdehyde (MDA), and glutathione s-transferase (GST) increased significantly in a dose-dependent manner, while superoxide dismutase (SOD) decreased. The comet assay revealed that myco-synthesized SeNPs could cause breaks in the DNA levels. In silico study revealed that SeNPs had promising antioxidant properties. In conclusion, myco-synthesized SeNPs have the potential to be used as molluscicides and larvicides.

Nontarget Impacts of Herbicides on Spiders in Orchards

Spiders are key predators in many agroecosystems, including orchards. Despite the importance of spiders in biological control, pesticide nontarget effects on this group are poorly described. This is especially true for herbicides, which spiders frequently encounter as they move between the ground cover and tree canopy. We sought to determine the nontarget effects of seven herbicides used in orchards on three species of spiders that are commonly found in Washington state (USA) orchards: Pelegrina aeneola (Curtis) (Araneae: Salticidae), Philodromus cespitum (Walckenaer) (Araneae: Philodromidae), and Phanias watonus (Chamberlin & Ivie) (Araneae: Salticidae). Immature spiders were collected from orchards and used in laboratory assays. Single spiders were placed in vials with dried herbicide residues and mortality was evaluated after 1, 2, and 5 d. We also evaluated herbicide impacts on prey consumption rates and on spider movement using motion-tracking software. Only oxyfluorfen caused significant spider mortality. P. cespitum seemed to be less acutely sensitive to oxyfluorfen than the two salticid species. Several herbicide treatments significantly increased locomotion in P. cespitum, whereas rimsulfuron numerically decreased movement of P. aeneola. Sulfonylurea herbicides (rimsulfuron, halosulfuron) decreased prey consumption of P. aeneola. Our work indicates that although spiders may be less acutely sensitive to some pesticides than beneficial insects, they can be affected by sublethal effects of herbicides. Future work should determine if herbicide applications impact spider abundance in the field and reduce biological control services. In general, more work is needed on the impacts of herbicides on natural enemies.

Oxyfluorfen induces hepatotoxicity through lipo-sugar accumulation and inflammation in zebrafish (Danio rerio)

Oxyfluorfen (OXY) is widely used in agriculture as a herbicide, resulting in its continuous accumulation in the environment. The presence of OXY can be detected in soil and rivers. However, until now, the potential toxicity of OXY to aquatic organisms has not been evaluated. In this study, zebrafish was used as a model animal to evaluate OXY-induced liver toxicity. The study found that 0.25, 0.5, and 1 mg/L of OXY affected the early development of zebrafish and severely damaged the lipid and sugar metabolism in the liver of zebrafish larvae. Furthermore, a metabolic function disorder caused liver damage. OXY also caused inflammation by upregulating the inflammatory factors IL-6, IL-8, and TNF-α, and activated the apoptotic pathway to inhibit hepatocyte proliferation, resulting in zebrafish liver toxicity. Our research showed that OXY had certain toxic effects on zebrafish development and liver and could cause potential harm to other aquatic organisms and humans.

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.

Field Application of NIR Spectroscopy for the Discrimination of the Biomphalaria Species That Are Intermediate Hosts of Schistosoma mansoni in Brazil

Near Infrared Spectroscopy (NIRS) is a spectroscopic technique that evaluates the vibrational energy levels of the chemical bonds of molecules within a wavelength range of 750–2,500 nm. This simple method acquires spectra that provide qualitative and quantitative data on the chemical components of the biomass of living organisms through the interaction between the electromagnetic waves and the sample. NIRS is an innovative, rapid, and non-destructive technique that can contribute to the differentiation of species based on their chemical phenotypes. Chemical profiles were obtained by NIRS from three snail species (Biomphalaria glabrata, Biomphalaria straminea, and Biomphalaria tenagophila) that are intermediate hosts of Schistosoma mansoni in Brazil. The correct identification of these species is important from an epidemiological viewpoint, given that each species has distinct biological and physiological characteristics. The present study aimed to develop a chemometric model for the interspecific and intra-specific classification of the three species, focusing on laboratory and field populations. The data were obtained from 271 live animals, including 150 snails recently collected from the field, with the remainder being raised in the laboratory. Populations were sampled at three localities in the Brazilian state of Rio de Janeiro, in the municipalities of Sumidouro (B. glabrata) and Paracambi (B. straminea), and the borough of Jacarepaguá in the Rio de Janeiro city (B. tenagophila). The chemometric analysis was run in the Unscrambler® software. The intra-specific classification of the field and laboratory populations obtained accuracy rates of 72.5% (B. tenagophila), 77.5% (B. straminea), and 85.0% (B. glabrata). The interspecific differentiation had a hit rate of 75% for the field populations and 80% for the laboratory populations. The results indicate chemical and metabolic differences between populations of the same species from the field and the laboratory. The chemical phenotype, which is closely related to the metabolic profile of the snails, varied between environments. Overall, the NIRS technique proved to be a potentially valuable tool for medical malacology, enabling the systematic discrimination of the Biomphalaria snails that are the intermediate hosts of S. mansoni in Brazil.

Usage of pharmaceutical contraceptive drug for controlling Eobania vermiculata snails by baits technique

The present study focused on evaluating the effects of oral administration of three different concentrations of Yasmin® combined contraceptive pills (estrogen and progesterone) on reproductive hormones levels, histology of the ovotestis and rate of oviposition of E. vermiculata for two months using baits technique. The levels of anti-müllerian hormone (AMH), Follicle stimulating hormone (FSH), Luteinizing hormone (LH), Estradiol (E2), Progesterone(PRG), Thyroid-stimulating hormone (TSH) and Testesterone (T) of treated snails were decreased with increasing the drug concentrations by percentages of -83.3%, -78.9%, - 59.6%,- 98.3 %, - 79.6 %, - 86.7% and 8.2%, respectively. Prolactin (PRL) level was significantly increased (86.9%) compared to control snails after 8 weeks of exposure. Histological investigations on the hermaphrodite glands of snails treated with 909 μg/gm. showed glandular hyperplasia, sloughing of germinal epithelium, acini sizes reduction, suppression of follicular growths, decreased luteinization and vasodilation. Male acini revealed histolytic of spermatogonia and mature sperms. The lowest concentration (303 μg/gm.) caused gradual decrease of the total egg counts that reach 50% at the 8^th week of treatment. Higher doses (606 and 909 μg/gm.) resulted in dramatic dwindling of egg numbers and inspiring complete egg cessation at the 7^th and 3^rd weeks of treatments, respectively. The applications of combined contraceptive drugs as baits give promising results for controlling high population densities of E. vermiculata snails at Sharkia Governorate, Egypt.

Assessment of hematological, hepato-renal, antioxidant, and hormonal responses of Clarias gariepinus exposed to sub-lethal concentrations of oxyfluorfen

Little is known about the effects of oxyfluorfen, a diphenyl ether herbicide, exposure on the African catfish (Clarias gariepinus) health. Consequently, the existing investigation was designed to highlight the impacts of oxyfluorfen exposure on C. gariepinus hematological indices, liver and kidney functions, reproductive hormones, and oxidative status. Furthermore, a consequent 10-day depuration period was adopted to evaluate the recovery of the disturbed indicators to normal values. In the first experiment, the 96-h lethal concentration 50 (LC₅₀) of oxyfluorfen for C. gariepinus was determined using probit analysis. Next, in a second experiment, 180 healthy fish (average initial body weight: 164.23 ± 0.24) were randomly assigned to 4 experimental groups exposed to 0, 1/10, 1/8, or 1/5 96-h LC₅₀ of oxyfluorfen. The hematological profile, hepatic enzymes, kidney damage byproducts, reproductive hormones, oxidative stress, and lipid peroxidation indicators together with acetylcholinesterase (AChE) content were assessed. A histopathological examination of the hepatic, renal, brain, and testicular tissues was accomplished. Moreover, the expression of the oxidative stress-related gene was carried out. The results showed that 96-h LC₅₀ of oxyfluorfen for C. gariepinus was 11.698 mg/L. Exposure to sublethal levels of oxyfluorfen induced macrocytic hypochromic anemia, leukopenia, lymphopenia, monocytopenia, and eosinopenia. Also, a concentration-dependent increase in alanine transaminase, alkaline phosphatase, aspartate transaminase, urea, creatinine, catalase, and malondialdehyde was detected following oxyfluorfen exposure together with upregulation of catalase gene. But, significant concentration-dependent reductions in AChE, glutathione transferase, reduced to oxidized glutathione ratio, estradiol, and testosterone activities were recorded. These biochemical alterations were accompanied by pathological perturbations in hepatic, renal, brain, and testicular tissues. Following 10 days of recovery, only the hematological impairments were abolished. Conclusively, the herbicides oxyfluorfen could induce multiple negative impacts on C. gariepinus with oxidative stress as a probable underlying mechanism. Additionally, a recovery period of 10 days was not enough to restore these impairments.

Caenorhabditis elegans as a tool for environmental risk assessment: emerging and promising applications for a "nobelized worm"

Caenorhabditis elegans has been an invaluable model organism in research fields such as developmental biology and neurobiology. Neurotoxicity is one of the subfields greatly profiting from the C. elegans model within biomedical context, while the corresponding potential of the organism applied to environmental studies is relevant but has been largely underexplored. Within the biomedical scope, the implication of metals and organic chemicals with pesticide activity (hereinafter designated as pesticides) in the etiology of several neurodegenerative diseases has been extensively investigated using this nematode as a primary model organism. Additionally, as a well-known experimental model bearing high sensitivity to different contaminants and representing important functional levels in soil and aquatic ecosystems, C. elegans has high potential to be extensively integrated within Environmental Risk Assessment (ERA) routines. In spite of the recognition of some regulatory agencies, this actual step has yet to be made. The purpose of this review is to discuss the major advantages supporting the inclusion of C. elegans in lower tiers of ERA. Special emphasis was given to its sensitivity to metals and pesticides, which is similar to that of other model organisms commonly used in ERA (e.g. Daphnia magna and Eisenia sp.), and to the large array of endpoints that can be tested with the species, both concerning the aquatic and the soil compartments. The inclusion of C. elegans testing may hence represent a relevant advance in ERA, providing ecologically relevant insights toward improvement of the regulatory capacity for establishing appropriate environmental protection benchmarks.