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The aim of this study was to evaluate the sensitivity of the prawn Palaemon argentinus to the pyrethroid cypermethrin (CYP) and the tetramic acid spirotetramat (STM). These treatments were compared with prawns collected at a reference site to define their basal physiological state. Initially, physicochemical parameters and several pollutants at the selected site were analyzed. The LC 50 -96 h was determined in adult prawns. Then, prawns were exposed for 96 h to sublethal concentrations of CYP (0.0005 μg/l) and STM (0.44 mg/l) to evaluate the effects on some biochemical endpoints. A treatment combining both pesticides was also added at 5 % of these values. Controls with and without solvent (acetone) were included. The LC 50 -96 h values were 0.005 μg/l and 4.43 mg/l for CYP and STM, respectively. Moreover, some biomarkers linked to oxidative and energy metabolism were analyzed in the hepatopancreas and muscle of both essayed prawns and those at the basal state. The STM caused a significant decrease in total protein content (32 %) in contrast to the increase of protein carbonyl content (71 %) (p < 0.05). Also, glutathione S-transferase (52 %) and catalase (61 %) activities in the hepatopancreas of exposed prawns were higher compared to both the control and state basal groups (p < 0.05). In muscle, only a significant decrease in the lactate content (69 %) was caused by STM (p < 0.05). In addition, CYP caused a significant increase in the lactate dehydrogenase activity (110 %) in muscle and triacylglycerol content (73 %) in the hepatopancreas (p < 0.05). The integrated biomarker index (IBRv2) analysis showed that STM caused greater damage than CYP. Besides, the combined treatment showed an antagonistic interaction between both insecticides. The differential response of biomarkers to both CYP and STM exposure with respect to their basal levels shows a high sensitivity of P. argentinus demonstrating its potential role as a bioindicator organism., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

After their application in agricultural areas, pesticides are dispersed throughout the environment, causing contamination problems. In Argentina, the main promoter of transgenic biotechnology in the region, the total consumption of agrochemicals has increased significantly in recent years. Most chemicals dumped near surface waters eventually end up in bottom sediments and can be toxic to the organisms that live there. However, published data on the mixing of pesticides in this compartment is still scarce. The objective of this work was to detect and quantify pesticide residues in the sediment of rural streams in the Pampas region and to carry out acute and chronic risk assessment in these aquatic ecosystems. The study area comprises the mountainous system of Tandilia, located in one of the most productive agricultural areas in the country. The concentration of atrazine, acetochlor, chlorpyrifos, cypermethrin, and 2,4-D in the sediment of four rural streams was determined in three different seasons, and the toxic units (TU) and the risk ratios (RQ) were calculated. All the compounds analyzed were detected in most of the sampling seasons and study sites, at concentrations higher than those established in the national and international quality guidelines for the protection of aquatic biota in surface waters and for human consumption. Chlorpyrifos, cypermethrin, and acetochlor were the main pesticides contributing to the TU and RQ values, representing a medium or high ecological risk in most of the sites. Therefore, the evaluation of these pesticides in the bottom sediments could be a decisive factor in assessing the risk to the aquatic environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Pollutants as well as starvation usually modify homeostasis of neutral lipids in aquatic organisms. However, studies on the simultaneous effects of both stressors are scarce. The aim of this study was to evaluate the effect of toxicant exposure under starvation conditions on neutral lipids of the freshwater snail Pomacea canaliculata, selected as the model organism. Starved adult male snails were exposed to sublethal concentration of the pesticide cypermethrin (100 µg/L) during 4 and 10 days. Fed snails were sacrificed at the onset of the experiment (T 0 ), along with starved snails exposed to the pesticide vehicle (ethanol) and another group without solvent served as controls. Total lipid content, neutral lipid classes, fatty acid composition, and pesticide accumulation were determined in the digestive gland of snails. The ethanol concentration used was not an additional stressful agent. As expected, starvation caused a decrease in neutral lipid content in the digestive gland of snails with respect to T 0 snails. Pesticide exposure caused, on the other hand, an increase in triacylglycerol content compared to ethanol exposure at day 10 of the bioassay. This increment correlated with the bioconcentration of cypermethrin, which was 47% higher by day 10 than by day 4. The fatty acid profile of triacylglycerols in the digestive gland was significantly altered under starvation and pesticide exposure. Stressed male snails showed the ability to preserve polyunsaturated fatty acids, as evidenced by their significant increase with respect to T 0 snails. These results suggest that the alteration of lipid homeostasis could be involved in an adaptive mechanism of aquatic organisms to lipophilic and obesogenic pollutants., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

The aim of this study was to evaluate the effects of the last generation insecticide spirotetramat (STM) on embryos and larvae of the freshwater prawn Macrobrachium borellii. Both embryos and larvae were exposed to serial dilutions of STM to determine the LC 50 values. After 96-h of exposure, live larvae were fixed for histological analysis. In addition, ovigerous females were exposed to a sublethal concentration of STM (1.7 mg/L) for 96 h to evaluate the activity of the enzymes catalase, glutathione-S-transferase, and superoxide dismutase as well as the lipoperoxidation (LPO) and protein oxidation levels in embryos. The larvae showed a high sensitivity to STM evidenced by the LC 50 -96 h value (0.011 mg/L). On the contrary, the embryos were highly resistant to STM exposure, and no lethal effect was observed in the treatments with high concentrations of this insecticide (LC 50 -96 h > 150 mg/L). Among all the biochemical parameters evaluated in the embryos exposed to STM, only LPO showed a significant increase compared to controls. This was probably due to a restricted entry of the insecticide through the embryonic coat. Thus, a preliminary study of the structure and permeability of the embryonic coat was carried out in control embryos. The analysis by electron microscopy revealed that its structure is formed by four embryonic envelopes composed of multiple layers while the assay with a fluorescent probe revealed that the embryonic coat increases its permeability during development. STM caused significant histopathological alterations in the hepatopancreas and gills of larvae. This study showed that although the embryos of M. borellii could be protected by the embryonic coat, the larvae are very vulnerable to the STM toxicity. So, it is necessary to continue evaluating the effects of these new pesticides on non-target organisms, such as aquacultured species, to help predict their ecotoxicological risks derived from the increasing agricultural activity developed worldwide., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to evaluate the toxic effects of the pesticide cypermethrin (CYP) in the digestive gland of the apple snail, Pomacea canaliculata, analysing histological and histochemical alterations. Adult snails were exposed to sublethal CYP concentrations (10, 25, and 100 µg/L) under acute (1 day) and sub-chronic (14 days) conditions. Histological analyses of the morphology of the digestive gland were performed and a histopathological condition index (HI) was calculated. Also, both intracellular accumulation of lipofuscins (LF) and neutral lipids (NL) were evaluated. CYP exposure induced tissue damage to this organ, such as disorganisation of the connective tissue, fibrosis, haemocytic infiltration, atrophy, and necrosis under acute and sub-chronic conditions. These alterations, integrated into a single HI value, revealed notable CYP effects during both acute and sub-chronic exposures. Cell type replacement, measured as Vv BAS , was only observed in the sub-chronic treatment. Under acute conditions, the pyrethroid affected NL accumulation at the highest concentration, while in sub-chronic conditions NL accumulation was only observed at the lowest concentrations. P. canaliculata also showed a dose-dependent response of LF under acute CYP exposure conditions. However, under sub-chronic conditions, this parameter was not sensitive to pesticide exposure. All these relevant structural lesions may affect the normal function of the digestive gland, even though the species presented additional mechanisms, as infiltration of hemocyte and basophilic cell hyperplasia, that help it to tolerate the exposure to pollutants. This study showed that some histological and histochemical parameters are sensitive in P. canaliculata at CYP concentrations to which the snail could be exposed in the environments it inhabits., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier B.V.)

The aim of this study was to evaluate the acute effects of the pyrethroid cypermethrin (CYP) and the last generation pesticide spirotetramat (STM) on the prawn Macrobrachium borellii. Initially, the 96-h LC 50 was determined in adult prawns. Then, prawns were exposed to sublethal concentrations of pesticides (5% and 20% of the 96-h LC 50 values) for four days and hepatopancreas were dissected for biomarkers analyses. Total protein and uric acid content, glutathione S-transferase (GST) activity, levels of lipid peroxidation (LPO), and protein oxidation (PO) were evaluated. Additionally, the presence of histopathological changes, lipofuscins, and neutral lipids accumulation were analyzed. The 96-h LC 50 values were 0.12 μg/L and 8.2 mg/L for CYP and STM, respectively. The total proteins and uric acid content were not significantly affected by the treatments (p > 0.05). STM significantly affected the GST activity only at the highest concentration (p < 0.001). However, LPO and OP levels were affected by the lowest concentrations of both pesticides (p < 0.003). CYP and STM caused dose-dependent histological damage as was indicated by the histopathological index. The accumulation of lipofuscins showed a dose-dependent response, while the neutral lipids were significantly accumulated in the prawns exposed to the lowest concentration of both pesticides (p < 0.001). The integrated biomarker index (IBRv2) results indicated that the histological parameters represented the most sensitive biomarkers in M. borellii exposed to CYP and STM. Besides, the pyrethroid showed the highest response at concentration ranges that could be present in its natural environments., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The aim of the present work was to study the effect of the pyrethroid cypermethrin (CYP) on the non-target freshwater snail Chilina parchappi. Initially, the sensitivity of adult snails to CYP was evaluated via the 96-h LC 50 test. Then, snails were exposed to subtethal CYP concentrations (0.1 and 10 mg/l) for 1, 4 and 10 days and the digestive glands were dissected for biomarkers analyses. Enzymatic activity of catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), as well as total glutathione reduced (GSH) levels, were determined. Histological analyses of morphology, intracellular accumulation of lipofucsins and neutral lipids accumulation in the digestive gland were also evaluated. As compared to other molluscs, C. parchappi showed high resistance to CYP exposure evidenced by the 96-h LC 50 value (44.59 mg/l). Snails exposed to sublethal CYP concentrations showed a statistically significant increase (p < 0.01) in GST (79-116%) and GPx (45-190%) activities with respect to controls. However, CAT activity showed a tendency to decrease with CYP treatment but was not statistically significantly different compared to control. Only high CYP concentration caused a statistically significant increase (p < 0.01) in GSH content (95-196%). There was evidence of structural changes in the digestive gland of snails exposed to CYP, showing a dose-dependent response. In exposed snails, some of the main symptoms included a reduction in the thickness of the epithelium, vacuolisation of the digestive cells and an increase in the number of excretory cells. Accumulation of lipofuscins (933-1006%) and neutral lipids (403%) were statistically significantly higher (p < 0.05) in snails exposed to CYP compared to control. This study showed that C. parchappii is quite tolerant to CYP exposure and that at sublethal concentrations, GSH metabolism could play a protective role against the pesticide harm in snails. Therefore, it would be interesting to study the response of this organism to other environmental stressors to assess its potential use in monitoring programs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Geraniol (GOH), like other plant-derived natural bioactive compounds, has been found to possess antiproliferative properties that are essential to cope with malignant tumors. However, the mechanisms of molecular action of GOH are not fully elucidated. The aim of this study was to evaluate the effect of GOH on some oxidative parameters in human tumor cell lines (HepG2 and A549). Cytotoxicity evaluated in cell lines by the MTT assay, genotoxicity by the comet assay, and lipid peroxidation by the TBARS. The activities of antioxidant the enzymes, superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST), were also analyzed. Additionally, intracellular reactive oxygen species (ROS), nitric oxide, and lactate production were determined in HepG2 cells. Both tumor cell lines showed a clear concentration-dependent response to GOH in several of the parameters evaluated. Lipids turned out to be more sensitive than DNA to oxidative damage induced by GOH. TBARS levels increased with respect to control (p < 0.05) by 33% and 122% in HepG2 and A549 cells, respectively treated with 200 μM GOH. However, GOH caused a statistically significant decrease in SOD and CAT activities in HepG2 cells only. GST was not affected in any cell lines. GOH induced the production of ROS but not nitric oxide in HepG2, which shows that ROS were mainly responsible for oxidative damage. Lactate release increased statistically significantly compared to control (p < 0.001), by 41% and 86% at 200 and 800 μM GOH respectively, showing that this monoterpene also affected the glycolytic pathway in HepG2 cells. These results suggest that oxidative stress could mediate the anti-proliferative effects of GOH in HepG2 and A549 cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier B.V. All rights reserved.)

The present study was aimed at evaluating the effect of male presence on ovarian maturation in juvenile females and the role of potential chemical, visual and tactile cues emitted by males in that physiological process. A highly gregarious caridean shrimp with sexual dimorphism, Neocaridina davidi, was used as experimental model. We tested the hypothesis that male presence accelerates ovarian maturation, mainly through chemical cues. Two experiments were performed. In Experiment 1, juvenile females were reared with adult males, adult females or alone, allowing full contact among shrimps. In Experiment 2, these treatments were evaluated allowing chemical and visual communication, only visual communication, or only chemical communication among shrimps. In both experiments juvenile females were observed once a week under a stereomicroscope to determine ovarian growth rate. Although male presence was not necessary for ovarian maturation, it clearly accelerated the rate of ovarian growth, particularly in the last maturation phase. This lead to relatively longer mature ovaries with higher lipid content. On the contrary, the presence of adult females delayed ovarian maturation in juvenile females, while females reared alone showed an intermediate ovarian growth. All these results suggest that adult males release certain cues that stimulate ovarian maturation, while adult females release cues that delay this physiological process. Neither visual cues nor chemical cues released at a distance from females were responsible, either alone or in combination, for the observed effects. Ovarian growth was only influenced when shrimps were allowed to interact freely, probably because of the "mounting" behavior of males towards females. Tactile cues and/or potential chemical cues released by males during this behavior may mediate male stimulatory effect on ovarian growth. Altogether, present results partially support our initial hypothesis and contribute to increase the limited amount of information available on the role of intraspecific multimodal communication in non-behavioral reproductive processes in invertebrate species., (Copyright © 2018 Elsevier GmbH. All rights reserved.)