Ecotoxicological effects of pyraclostrobin on tilapia (Oreochromis niloticus) via various exposure routes

Pyraclostrobin induces developmental toxicity and cardiotoxicity through oxidative stress and inflammation in zebrafish embryos

Pyraclostrobin, a typical representative of strobilurin fungicides, is extensively used in agriculture to control fungi and is often detected in water bodies and food. However, the comprehensive toxicological molecular mechanism of pyraclostrobin requires further study. To assess the toxic effects and underlying mechanisms of pyraclostrobin on aquatic organisms, zebrafish embryos were exposed to pyraclostrobin (20, 40, and 60 μg/L) until 96 h post fertilization (hpf). These results indicated that exposure to pyraclostrobin induces morphological alterations, including spinal curvature, shortened body length, and smaller eyes. Furthermore, heart developmental malformations, such as pericardial edema and bradycardia, were observed. This indicated severe cardiotoxicity induced by pyraclostrobin in zebrafish embryos, which was confirmed by the dysregulation of genes related to heart development. Besides, our findings also demonstrated that pyraclostrobin enhanced the contents of reactive oxygen species (ROS) and malondialdehyde (MDA), up-regulated catalase (CAT) activity, but inhibited superoxide dismutase (SOD) activity. Subsequently, the NF-κb signaling pathway was further studied, and the results indicated that the up-regulation of tnf-α, tlr-4, and myd88 activated the NF-κb signaling pathway and up-regulated the relative expression level of pro-inflammatory cytokines, such as cc-chemokine, ifn-γ, and cxcl-clc. Collectively, this study revealed that pyraclostrobin exposure induces developmental toxicity and cardiotoxicity, which may result from a combination of oxidative stress and inflammatory responses. These findings provide a basis for continued evaluation of the effects and ecological risks of pyraclostrobin on the early development of aquatic organisms.

Bioaccumulation mediated by water solubility leads to differences in the acute toxicity of organophosphorus insecticides to zebrafish (Danio rerio)

The use of some organophosphate insecticides is restricted or even banned in paddy fields due to their high toxicity to aquatic organisms. The aim of this study is to elucidate the main pathways and target organs of organophosphate insecticide toxicity to fish exposed via different routes by integrating histopathological and biochemical techniques. Using malathion as the model drug, when the dosage is 20-60 mg/L, the toxicity of whole body and head immersion drugs to zebrafish is much higher than that of trunk immersion drugs. A dose of 21.06-190.44 mg/kg of malathion feed was fed to adult zebrafish. Although the dosage was already high, no obvious toxicity was observed. Therefore, we believe that the drug mainly enters the fish body through the gills. When exposed to a drug solution of 20 mg/L and 60 mg/L, the fish showed significant neurological behavioral abnormalities, and the pathological damage to key organs and brain tissue was the most severe, showing obvious vacuolization and the highest residual amount (8.72-47.78 mg/L). The activity of acetylcholinesterase was the most inhibited (54.69-74.68%). Therefore, brain tissue is the key toxic target organ of malathion in fish. In addition, we compared the bioaccumulation effects of different water-soluble organophosphorus insecticides in fish and their toxic effects. We found that the higher the water solubility of organophosphorus insecticides, the lower their toxicity to fish.

In Vitro, In Vivo, and In Silico Analysis of Pyraclostrobin and Cyprodinil and Their Mixture Reveal New Targets and Signaling Mechanisms

Pyraclostrobin and cyprodinil are broad-spectrum fungicides that are used in crops to control diseases. However, they are excessively used and, as a result, end up in the environment and threaten human health and ecosystems. Hence, knowledge of their mechanisms of action is critical to revealing their environmental fate and negative effects and regulating their use. In the present study, we conducted a comprehensive study to show the adverse effects of pyraclostrobin, cyprodinil, and their mixture using zebrafish larvae and different cell lines. Several end points were investigated, including mortality, development, gene expression, reporter assays, and molecular docking simulations. We found that both compounds and their mixture caused developmental delays and mortality in zebrafish, with a higher effect displayed by pyraclostrobin. Both compounds altered the expression of genes involved in several signaling pathways, including oxidative stress and mitochondrial function, lipid and drug metabolisms, the cell cycle, DNA damage, apoptosis, and inflammation. A noteworthy result of this study is that cyprodinil and the mixture group acted as NFκB activators, while pyraclostrobin demonstrated antagonist activity. The AHR activity was also upregulated by cyprodinil and the mixture group; however, pyraclostrobin did not show any effect. For the first time, we also demonstrated that pyraclostrobin had androgen receptor antagonist activity.

Impacts of pyraclostrobin on intestinal health and the intestinal microbiota in common carp (Cyprinus carpio L.)

Pyraclostrobin (PYR) is a strobilurin fungicide that is commonly used in agriculture, and its use in agriculture may lead to an increase in its residue in the aquatic environment and may have a deleterious influence on the intestinal health of aquatic creatures. Here, common carp were chronically exposed to PYR (0, 0.5, or 5.0 μg/L) for 30 d to determine its effect on the physical and immunological barrier and intestinal microbiota in the intestine. PYR exposure caused significant histological changes; altered the mRNA expression levels of occludin, claudin-2, and zonula occludens-1 (ZO-1); induced oxidative stress in the common carp intestine; and increased the serum D-lactate and diamine oxidase (DAO) levels. Moreover, PYR significantly increased the protein expression levels of tumour necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1β), and IL-6 while decreasing the level of transforming growth factor beta (TGF-β). Further studies revealed that PYR significantly reduced lysozyme (LZM) and acid phosphatase (ACP) activities as well as complement 3 (C3) and immunoglobulin M (IgM) levels. Furthermore, PYR decreased gut microbial diversity while increasing the abundance of pathogenic bacteria such as Aeromonas and Shewanella, causing an intestinal microbial disturbances in common carp. These results imply that PYR has a negative impact on fish intestinal health and may pose serious health risks to fish by disrupting the intestinal microbiota, physical barrier, and immunological barrier in common carp.

Regional Variations in Pesticide Residue Detection Rates and Concentrations in Saudi Arabian Crops

There is a scarcity of evidence on the levels of pesticide residues among common crops grown in the different regions of the Kingdom of Saudi Arabia (KSA). The present study aims to fill this gap. We collected samples across four regions of KSA (N = 41 from the west, N = 146 from the central, N = 131 from the north and N = 74 samples from the east). Food samples were extracted and cleaned using the modified quick, easy, cheap, effective, rugged and safe (QuEChERS) methodology. Tandem mass (LC-MS/MS and GC-MS/MS) was used to detect pesticide residues. The highest pesticide residue detection rate was 89.7% in the central region, followed by 88.5% in the north, 83.8% in the east and 70.7% in the western region (p = 0.01). Pesticide residue detection rates were significantly higher in fruits than vegetables (p = 0.02). Cypermethrin detection was most common overall, particularly in the Western region (p = 0.002), and pyraclostrobin concentration was the highest among all residues investigated. In conclusion, high detection rates of moderately hazardous pesticide residues were found in various crops across regions in KSA. Routine biomonitoring programs across KSA regions should be implemented, as well as public health campaigns to decrease pesticide residue consumption and exposure.

Short-term effects of the strobilurin fungicide dimoxystrobin on zebrafish gills: A morpho-functional study

Strobilurins represent the most widely used class of fungicides nowadays andare considered relatively non-toxic to mammals and birds but highly toxic to aquatic biota. Dimoxystrobin is one of the novel strobilurins, recently included in the 3rd Watch List of the European Commission as available data indicate that it could pose a significant risk to aquatic species. As yet, the number of studies explicitly assessing the impact of this fungicide on terrestrial and aquatic species is extremely low, and the toxic effects of dimoxystrobin on fish have not been reported. Here we investigate for the first time the alterations induced by two environmentally relevant and very low concentrations of dimoxystrobin (6.56 and 13.13 μg/L) in the fish gills. morphological, morphometric, ultrastructural, and functional alterations have been evaluated using zebrafish as a model species. We demonstrated that even short-term exposure (96 h) to dimoxystrobin alters fish gills reducing the surface available for gas exchange and inducing severe alterations encompassing three reaction patterns: circulatory disturbance and both regressive and progressive changes. Furthermore, we revealed that this fungicide impairs the expression of key enzymes involved in osmotic and acid-base regulation (Na⁺/K⁺-ATPase and AQP3) and the defensive response against oxidative stress (SOD and CAT). The information presented here highlights the importance of combining data from different analytical methods for evaluating the toxic potential of currently used and new agrochemical compounds. Our results will also contribute to the discussion on the suitability of mandatory ecotoxicological tests on vertebrates before the introduction on the market of new compounds.

Cocktails of pesticide residues in Prochilodus lineatus fish of the Salado River (South America): First record of high concentrations of polar herbicides

Muscle and viscera (gills-liver) of the fish Prochilodus lineatus were obtained from four sites of lower course of Salado river and one site at Santa Fe river near to its confluence with Salado river from Santa Fe (Argentina) between December 2021 and February 2022. Sediment samples were also obtained from the same sites. All samples were analyzed for pesticide residues following the QuEChERS method to quantify 136 compounds by UHPLC-ESI-MS/MS and GC-EI-MS/MS. Overall, muscle fish tissue showed very high concentrations (maximum concentrations detected) of the insecticide cypermethrin (204 μg/kg), polar herbicides (glyphosate; 187 μg/kg and its degradation product (aminomethylphosphonic acid) AMPA; 3116 μg/kg, and glufosinate-ammonium; 677 μg/kg), and the fungicide pyraclostrobin (50 μg/kg). In viscera samples, high values of cypermethrin (506 μg/kg), chlorpyrifos (78 μg/kg), and lambdacyhalothrin (73 μg/kg) were the main pesticides found. Mean residues concentrations detected among sites were not significantly different neither in muscle nor viscera of P. lineatus in most of the cases. Exceptionally, the southernmost studied site of the Lower Salado river showed significant differences in concentration of residues found in muscle, due to high concentrations of glyphosate and glufosinate-amonium (KW = 11.879 and KW = 13.013, respectively, P < 0.05). Other norther Lower Salado river site showed significant higher AMPA concentration in fish viscera than in the rest of the studied sites (KW = 12.86 P < 0.05). Some sediment samples showed low levels of herbicides such as glyphosate (24 μg/kg) and fungicides. However, the world highest levels of polar herbicides were recorded in fish muscle. The results of this study highlight the need for periodic monitoring due to the high concentration of pesticides and its potential risk in a very important commercial freshwater fish from Argentina, which is consumed locally and exported to other countries for human consumption.

The thioredoxin expression of Cristaria plicata is regulated by Nrf2/ARE pathway under microcystin stimulation

Thioredoxin plays an important role in inhibiting apoptosis and protecting cells from oxidative stress. This study was aimed to clarify how the expression of Trx from Cristaria plicata is regulated by Nrf2/ARE pathway. The expression of CpTrx mRNA was significantly up-regulated in gill and kidney tissues under microcystin stress. The Nrf2 gene of Cristaria plicata was identified to possess an auto active domain bit. While CpNrf2 was knocked down by specific small RNA, CpTrx mRNA expression was significantly down-regulated. The promoter of CpTrx gene had high transcriptional activity, and this basic transcriptional activity persisted after ARE element mutation. The region of promoter -206 to +217 bp was a core promoter region and had forward regulatory elements. Gel shift Assay exhibited that the CpTrx promoter could bind to the purified proteins CpNrf2 and CpMafK in vitro. The binding phenomenon disappeared after the ARE element mutation in promoter region. Subcellular localization experiments displayed that fluorescence overlap between CpNrf2 and Trx promoter increased under microcystin toxin stress. These results suggested that Trx expression was regulated by Nrf2/ARE pathway under oxidative stress.

Resveratrol alleviates pyraclostrobin-induced lipid peroxidation, oxidative stress, and DNA damage in rats

Pyraclostrobin (Pyra) is a fungicide in the strobilurin class and has proven to be very toxic to organisms primarily aquatic species. Resveratrol (Res) is a phytoalexin that exhibits multiple bioactivities as anti-oxidative, anti-inflammatory, cardiovascular protective, and anti-aging and is found in plant species such as mulberry, peanut, and grape. This study aimed to determine the protective effect of Res against Pyra-induced lipid peroxidation, oxidative stress, and DNA damage in rats. For this purpose, a total of 48 male rats divided into 6 groups - 8 in each group - were exposed to 30 mg/kg Pyra by oral gavage once a day for 30 days and to three different concentrations of Res (5, 10, and 20 mg/kg) together with Pyra. Pyra administration increased liver enzyme parameters and malondialdehyde (MDA) levels whereas decreased glutathione (GSH) levels and activities of superoxide dismutase (SOD) and catalase (CAT). Also, Pyra treatment increased pro-apoptotic (Bax), apoptotic (Caspase-3, Caspase-8, and Caspase-9), pro-inflammatory (NFκB), cancer (CYP2E1), and cell regulatory (p53) gene expressions and decreased anti-apoptotic (Bcl-2) gene expression in the liver. Furthermore, DNA damage in blood and histopathological changes in the liver and kidney were observed with Pyra administration. In contrast, Res administrations in a dose-dependent manner improved Pyra-induced lipid peroxidation, oxidative and DNA damages, expression levels of these genes in the liver, and histopathological changes in the liver and kidney. Consequently, the treatment of Res, known for its anti-oxidant and protective properties, exhibited a protective effect on Pyra-induced lipid peroxidation, oxidant/anti-oxidant status, gene expressions, and DNA damage in rats.

Residual analysis of QoI fungicides in multiple (six) types of aquatic organisms by UPLC-MS/MS under acutely toxic conditions

In view of the significance of food safety and the possible relationship between residual enrichment and acute toxicity for pesticides in different aquatic organisms, it is essential to establish a sensitive and reliable determination method for pesticides in different aquatic organisms to analyze the enrichment levels. Quinone outside inhibitor fungicides (QoIs) are lipophilic fungicides that pose environmental threats to aquatic organisms. Previous research has mainly focused on QoI residues in aquatic organisms under chronic toxicity, whereas less is known about how pesticide residues differ among aquatic organism under acutely toxic conditions. In the present study, the residues of QoIs in aquatic organisms (Danio rerio, Rana pipiens, Cherax quadricarinatus, Misgurnus anguillicaudatus, Corbicula fluminea, and Ampullaria gigas) were analyzed by ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) coupled with a proposed QuEChERS method. The proposed method was validated in terms of linearity (coefficients of determination of 0.9980-0.9999), the limits of quantification (0.01 μg·kg^-1), the relative standard deviation (0.6-4.4%), and recovery (70.12-118.15%). The results demonstrated that the proposed method fulfilled the requirements for pesticide analysis in all tested aquatic organisms. The residues of QoIs in the same aquatic organism exposed to QoI concentrations of 5 and 500 μg L^-1 decreased in the order pyraoxystrobin > pyraclostrobin > triclopyricarb > picoxystrobin > azoxystrobin > fluoxastrobin. Furthermore, the acute toxicity was strongly correlated with the enrichment level of the QoIs in aquatic organisms. This study provides the first documentation of a correlation between the enrichment level of QoIs and acute toxicity in aquatic organisms, which provides a basis for the management of agrochemicals considering aquatic ecological risks.

Hepatopancreas toxicity and immunotoxicity of a fungicide, pyraclostrobin, on common carp

Pyraclostrobin (PYR), a strobilurin fungicide, has been widely used to control fungal diseases, posing potential risk to aquatic organisms. However, the toxic effects of PYR to fish remained largely unknown. In this study, common carp (Cyprinus carpio L.) was exposed to environmentally relevant levels of PYR (0, 0.5 and 5.0 μg/L) for 30 days to assess its chronic toxicity and potential toxicity mechanism. The results showed that long-term exposure to PYR induced hepatopancreas damage as evident by increased in serum transaminase activities (AST and ALT). Moreover, PYR exposure remarkably enhanced the expressions of hsp70 and hsp90, decreased the levels of antioxidant enzymes and biomarkers and promoted the reactive oxygen species (H₂O₂ and O₂^-) and MDA contents in carp hepatopancreas. PYR exposure also upregulated apoptosis-related genes (bax, apaf-1, caspase-3 and caspase-9) and reduced anti-apoptosis gene bcl-2 in fish hepatopancreas. Moreover, PYR exposure altered the expressions of inflammatory cytokines (IL-1β, IL-6, TNF-α and TGF-β) in the serum and hepatopancreas and the level of NF-κB p65 in the hepatopancreas. Further research indicated that PYR exposure markedly changed the levels of immune parameters (LYZ, C3, IgM, ACP and AKP) in the serum and/or hepatopancreas, indicating that chronic PYR exposure also has immunotoxicity on fish. Additionally, we found that PYR exposure upregulated p38 and jnk MAPK transcription levels, suggesting that MAPK may be play important role in PYR-induced apoptosis and inflammatory response in the hepatopancreas of common carp. In summary, PYR exposure induced oxidative stress, triggered apoptosis, inflammatory and immune response in common carp, which can help to elucidate the possible toxicity mechanism of PYR in fish.

Comprehensive study of the effects of strobilurin-based fungicide formulations on Enchytraeus albidus

Excessive application of fungicides in crop fields can cause adverse effects on soil organisms and consequently affect soil properties. Existing knowledge on the effects of strobilurin fungicides has been primarily based on toxicity tests with active ingredients, while the effects of fungicide formulations remain unclear. Therefore, this work aims to provide new data on the effects of three commercial formulations of strobilurin fungicides on the soil organism Enchytraeus albidus. The tested fungicide formulations were Retengo® (pyraclostrobin-PYR), Zato WG 50® (trifloxystrobin-TRI) and Stroby WG® (kresoxim-methyl-KM). In laboratory experiments, multiple endpoints were considered at different time points. The results showed that PYR had the greatest impact on survival and reproduction (LC₅₀ = 7.57 mg_a.i.kg_soil^-1, EC₅₀ = 0.98 mg_a.i.kg_soil^-1), followed by TRI (LC₅₀ = 72.98 mg_a.i.kg_soil^-1, EC₅₀ = 16.93 mg_a.i.kg_soil^-1) and KM (LC₅₀ = 73.12 mg_a.i.kg_soil^-1, EC₅₀ ≥ 30 mg_a.i.kg_soil^-1). After 7 days of exposure, MXR activity was inhibited at the highest concentration of all fungicides tested (6 mg_PYRkg_soil^-1, 15 mg_TRIkg_soil^-1 and 30 mg_KMkg_soil^-1). Furthermore, oxidative stress (induction of SOD, CAT and GST) and lipid peroxidation (increase in MDA) were also observed. In addition, there was a decrease in total available energy after exposure to PYR and KM. Exposure to fungicides resulted in a shift in the proportions of carbohydrates, lipids, and proteins affecting the amount of available energy. In addition to the initial findings on the effects of strobilurin formulations on enchytraeids, the observed results suggest that multiple and long-term exposure to strobilurin formulations in the field could have negative consequences on enchytraeid populations.

Facial Irritant Contact Dermatitis Caused by Pyraclostrobin

Contact dermatitis and facial contact dermatitis caused by pesticides are not uncommon in China. However, clinically, due to the wide variety of pesticides, they mainly appear in the form of case reports. We reported a 70-year-old male patient developed facial irritant contact dermatitis (ICD) due to pyraclostrobin which was sprayed on his face. Initially, he felt facial burning and tingling, and localized erythematous-edematous and scaly rash appeared on his face as well as front hairline scalp. During the outpatient visit, the main symptoms were a facial burning sensation, itching, and tingling. The patient’s facial lesions improved after treatment. To better protect the skin of agricultural workers, preventive measures should be undertaken, such as personal protective equipment, gas masks, protective clothing and goggles, which are indispensable for manual pesticide spraying. Pyraclostrobin diluted according to the instructions is a potential source of ICD. Agricultural workers should undertake preventive measures during manual pesticide spraying. Safety education and publicity are particularly important. We need dermatologists to spread knowledge and agricultural workers to develop the right protective habits.

Fish metabolome from sub-urban lakes of the Paris area (France) and potential influence of noxious metabolites produced by cyanobacteria

The recent democratization of high-throughput molecular phenotyping allows the rapid expansion of promising untargeted multi-dimensional approaches (e.g. epigenomics, transcriptomics, proteomics, and/or metabolomics). Indeed, these emerging omics tools, processed for ecologically relevant species, may present innovative perspectives for environmental assessments, that could provide early warning of eco(toxico)logical impairments. In a previous pilot study (Sotton et al., Chemosphere 2019), we explore by ¹H NMR the bio-indicative potential of metabolomics analyses on the liver of 2 sentinel fish species (Perca fluviatilis and Lepomis gibbosus) collected in 8 water bodies of the peri-urban Paris' area (France). In the present study, we further investigate on the same samples the high potential of high-throughput UHPLC-HRMS/MS analyses. We show that the LC-MS metabolome investigation allows a clear separation of individuals according to the species, but also according to their respective sampling lakes. Interestingly, similar variations of Perca and Lepomis metabolomes occur locally indicating that site-specific environmental constraints drive the metabolome variations which seem to be influenced by the production of noxious molecules by cyanobacterial blooms in certain lakes. Thus, the development of such reliable environmental metabolomics approaches appears to constitute an innovative bio-indicative tool for the assessment of ecological stress, such as toxigenic cyanobacterial blooms, and aim at being further follow up.

Nanomaterials and nanotechnology for the delivery of agrochemicals: strategies towards sustainable agriculture

Nanomaterials (NMs) have received considerable attention in the field of agrochemicals due to their special properties, such as small particle size, surface structure, solubility and chemical composition. The application of NMs and nanotechnology in agrochemicals dramatically overcomes the defects of conventional agrochemicals, including low bioavailability, easy photolysis, and organic solvent pollution, etc. In this review, we describe advances in the application of NMs in chemical pesticides and fertilizers, which are the two earliest and most researched areas of NMs in agrochemicals. Besides, this article concerns with the new applications of NMs in other agrochemicals, such as bio-pesticides, nucleic acid pesticides, plant growth regulators (PGRs), and pheromone. We also discuss challenges and the industrialization trend of NMs in the field of agrochemicals. Constructing nano-agrochemical delivery system via NMs and nanotechnology facilitates the improvement of the stability and dispersion of active ingredients, promotes the precise delivery of agrochemicals, reduces residual pollution and decreases labor cost in different application scenarios, which is potential to maintain the sustainability of agricultural systems and improve food security by increasing the efficacy of agricultural inputs.