Determinants of pesticides use among tomato farmers in the Bono and Ahafo regions of Ghana.

Tomato production plays a crucial role in the livelihoods of farmers and agricultural households in the forest savanna transitional belt of Ghana. However, the success of tomato cultivation is hindered by the presence of insect pests and diseases, necessitating the use of agricultural inputs. This study aimed to identify the pesticides used in tomato farming, assess their World Health Organization (WHO) active ingredient hazard class, determine the precautionary behaviour associated with pesticide use by tomato farmers, and elucidate the socio-economic factors influencing pesticide usage in the Bono and Ahafo regions of Ghana. A multistage sampling procedure was employed to select 1009 respondents, who were administered a structured questionnaire. Descriptive statistics and logistic regression models were used to analyse the collected data. The results revealed that tomato farmers utilized 15 types of insecticides (e.g., lambda and chlorpyrifos ethyl based), 8 types of fungicides (e.g., mancozeb and sulphur + copper based), and 6 types of weedicides (mostly glyphosate based) on their crops. Notably, four insecticides and two fungicides types were found to be unregistered products. Lambda-cyhalothrin-based insecticides and mancozeb-based fungicides were predominantly used by the farmers. The assessed pesticides exhibited varying levels of hazard, ranging from slight to moderate. The study found that farmer training was a significant driver influencing insecticide use, while the educational level of farmers and average yield played important roles in determining fungicide use. Socio-economic factors such as being the head of the household, employing farm workers, the cultivated tomato variety, and farmer training influenced weedicide use. The type of tomato variety cultivated emerged as the primary socio-economic driver of pesticide use. The study recommended the establishment and implementation of a systematic monitoring regime for pesticide product marketing and use, with the aim of reducing the utilization of unregistered products by farmers. Implementing these measures supports sustainable tomato farming in the Bono and Ahafo regions of Ghana.

Fungicide ingestion reduces net energy gain and microbiome diversity of the solitary mason bee.

Fungicides are frequently used during tree fruit bloom and can threaten insect pollinators. However, little is known about how non-honey bee pollinators such as the solitary bee, Osmia cornifrons, respond to contact and systemic fungicides commonly used in apple production during bloom. This knowledge gap limits regulatory decisions that determine safe concentrations and timing for fungicide spraying. We evaluated the effects of two contact fungicides (captan and mancozeb) and four translaminar/plant systemic fungicides (cyprodinil, myclobutanil, penthiopyrad, and trifloxystrobin) on larval weight gain, survival, sex ratio, and bacterial diversity. This assessment was carried out using chronic oral ingestion bioassays where pollen provisions were treated with three doses based on the currently recommended field use dose (1X), half dose (0.5X), and low dose (0.1X). Mancozeb and penthiopyrad significantly reduced larval weight and survival at all doses. We then sequenced the 16S gene to characterize the larvae bacteriome of mancozeb, the fungicide that caused the highest mortality. We found that larvae fed on mancozeb-treated pollen carried significantly lower bacterial diversity and abundance. Our laboratory results suggest that some of these fungicides can be particularly harmful to the health of O. cornifrons when sprayed during bloom. This information is relevant for future management decisions about the sustainable use of fruit tree crop protection products and informing regulatory processes that aim to protect pollinators.

Exposure to the environmentally relevant fungicide Maneb: Studying toxicity in the soil nematode Caenorhabditis elegans.

Maneb is a manganese-containing ethylene bisdithiocarbamate fungicide and is still commonly used as no cases of resistance have been documented. However, studies have shown that Maneb exposure has neurodegenerative potential in mammals, resulting in symptoms affecting the motor system. Despite its extensive use, structural elucidation of Maneb has only recently been accomplished by our group. This study aimed to examine the bioavailability of Maneb, the quantification of oxidative stress-related endpoints and neurotransmitters employing pure Maneb, its metabolites and structural analogues, in the model organism Caenorhabditis elegans. Exposure to Maneb did not increase the bioavailability of Mn compared to manganese chloride, although Maneb was about 8 times more toxic with regard to lethality. Maneb generated not significantly reactive oxygen and nitrogen species (RONS) but decreased the ATP level while increasing the amount of glutathione and its oxidized form in a dose-dependent manner. Nevertheless, an alteration in the neurotransmitter homeostasis of dopamine, acetylcholine, and gamma-butyric acid (GABA) was observed as well as morphological changes in the dopaminergic neurons upon Maneb exposure, which underlines the assumption of the neurotoxic potential of Maneb. This study showed that Maneb exhibits effects based on a combined interaction of the ligand and manganese.

Low concentrations of ethylene bisdithiocarbamate pesticides maneb and mancozeb impair manganese and zinc homeostasis to induce oxidative stress and caspase-dependent apoptosis in human hepatocytes.

The worldwide and intensive use of phytosanitary compounds results in environmental and food contamination by chemical residues. Human exposure to multiple pesticide residues is a major health issue. Considering that the liver is not only the main organ for metabolizing pesticides but also a major target of toxicities induced by xenobiotics, we studied the effects of a mixture of 7 pesticides (chlorpyrifos-ethyl, dimethoate, diazinon, iprodione, imazalil, maneb, mancozeb) often detected in food samples. Effects of the mixture was investigated using metabolically competent HepaRG cells and human hepatocytes in primary culture. We report the strong cytotoxicity of the pesticide mixture towards hepatocytes-like HepaRG cells and human hepatocytes upon acute and chronic exposures at low concentrations extrapolated from the Acceptable Daily Intake (ADI) of each compound. Unexpectedly, we demonstrated that the manganese (Mn)-containing dithiocarbamates (DTCs) maneb and mancozeb were solely responsible for the cytotoxicity induced by the mixture. The mechanism of cell death involved the induction of oxidative stress, which led to cell death by intrinsic apoptosis involving caspases 3 and 9. Importantly, this cytotoxic effect was found only in cells metabolizing these pesticides. Herein, we unveil a novel mechanism of toxicity of the Mn-containing DTCs maneb and mancozeb through their metabolization in hepatocytes generating the main metabolite ethylene thiourea (ETU) and the release of Mn leading to intracellular Mn overload and depletion in zinc (Zn). Alteration of the Mn and Zn homeostasis provokes the oxidative stress and the induction of apoptosis, which can be prevented by Zn supplementation. Our data demonstrate the hepatotoxicity of Mn-containing fungicides at very low doses and unveil their adverse effect in disrupting Mn and Zn homeostasis and triggering oxidative stress in human hepatocytes.

Evaluation of the acute and sublethal toxicity of Mancozeb in Pacamã (Lophiosilurus alexandri).

The toxic potential of dithiocarbamates fungicides widely used in world agriculture is well known, among which Mancozeb is one of the most used. This study aimed to evaluate the toxicity of Mancozeb, determining the LC50% of the product and the behavioral and histological changes observed in fish of the Pacamã species through acute and sublethal toxicity tests. The first experiment was carried out on Pacamã fingerlings exposed to dosages of 0.5, 1, 2, 4, and 8mg/L of Mancozeb under the form ManzateWG®, for a total period of 96 hours in the acute experiment, and in the second experiment, fish were subjected to concentrations of 1/10 of those used in the acute experiment (0.05, 0.1, 0.2, 0.4 and 0.8mg/L, respectively), for 15 days in total. The 50% lethal concentration of ManzateWG® was calculated at the end of the acute experiment, presenting a value of 2.29mg/L at 96h for Pacamã fingerlings. A behavioral assessment was carried out through daily observation of the fish during both experiments, and an increase in mucus production was observed, as well as atypical social behavior in those exposed to the toxic agent. Histopathological evaluation was performed on livers collected after the end of the sublethal experiment, and the main hepatic alterations observed were cytoplasmic vacuolization, inflammatory infiltrate, and necrosis. Mancozeb has toxic potential and is capable of generating behavioral changes, as well as increasing the risk of liver damage in Pacamãs exposed to this compound.

A novel bidirectional regulation mechanism of mancozeb on the dissemination of antibiotic resistance.

The high abundance of antibiotic resistance genes (ARGs) in the fungicide residual environment, posing a threat to the environment and human health, raises the question of whether and how fungicide promotes the prevalence and dissemination of antibiotic resistance. Here, we reported a novel mechanism underlying bidirectional regulation of a typical heavy-metal-containing fungicide mancozeb on the horizontal transfer of ARGs. Our findings revealed that mancozeb exposure significantly exerted oxidative and osmotic stress on the microbes and facilitated plasmid-mediated ARGs transfer, but its metallic portions (Mn and Zn) were potentially utilized as essential ions by microbes for metalating enzymes to deal with cellular stress and thus reduce the transfer. The results of transcriptome analysis with RT-qPCR confirmed that the expression levels of cellular stress responses and conjugation related genes were drastically altered. It can be concluded mancozeb bidirectionally regulated the ARGs dissemination which may be attributed to the diverse effects on the microbes by its different portions. This novel mechanism provides an updated understanding of neglected fungicide-triggered ARGs dissemination and crucial insight for comprehensive risk assessment of fungicides.

Environmentally friendly and novel solid-liquid phase microextraction of maneb fungicide in fruits and vegetables.

The dithiocarbamates class has been widely used in agriculture practices because of lower toxicity and instability than organophosphates and carbamates. Among them, the maneb has been used to produce several fruits and vegetables, but its high ingestion can adversely affect human health. This work developed the Solid-Liquid Phase Microextraction (SLPME) for extraction of the maneb in foods sample with posterior determination by Flow injection analysis-Flame Absorption Atomic Spectroscopy (FIA-FAAS). Curve analytical had a linear range from 0.9 to 20.0 µmol L-1 maneb (A = 5.94 × 10-4 C (µmol L-1) + 6.93 × 10-4), good repeatability (4.07%) and reproducibility (3.39%), limits of quantification (5.98 µmol L-1) and detection (0.197 µmol L-1), which was above of the established by regulatory agencies. The extraction of the maneb was performed using 685 µL of the solution of the 1.00 × 10-3 mol L-1 of EDTA, and it has excellent recovery values from 80.85 to 106.51%. Therefore, the developed SLPME demonstrated an alternative environmentally friendly for quickly extracting maneb from food samples (apple, papaya, and tomato).

Cannabidiol Protects Dopaminergic-like Neurons against Paraquat- and Maneb-Induced Cell Death through Safeguarding DJ-1CYS106 and Caspase 3 Independently of Cannabinoid Receptors: Relevance in Parkinson's Disease.

Parkinson's disease (PD), a progressive neurodegenerative movement disorder, has reached pandemic status worldwide. This neurologic disorder is caused primarily by the specific deterioration of dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNc). Unfortunately, there are no therapeutic agents that slow or delay the disease progression. Herein, menstrual stromal cell-derived dopamine-like neurons (DALNs) intoxicated with paraquat (PQ2+)/maneb (MB) were used as a model system to elucidate the mechanism by which CBD protects the neural cell from apoptosis in vitro. According to immunofluorescence microscopy, flow cytometry, cell-free assay, and molecular docking analysis, we demonstrate that CBD offers protection to DALNs against PQ2+ (1 mM)/MB (50 µM)-induced oxidative stress (OS) by simultaneously (i) decreasing reactive oxygen species (ROS: O2•-, H2O2), (ii) maintaining the mitochondrial membrane potential (ΔΨm), (iii) directly binding to stress sensor protein DJ-1, thereby blunting its oxidation from DJ-1CYS106-SH into DJ-1CYS106-SO3, and (iv) directly binding to pro-apoptotic protease protein caspase 3 (CASP3), thereby disengaging neuronal dismantling. Furthermore, the protective effect of CBD on DJ-1 and CASP3 was independent of CB1 and CB2 receptor signaling. CBD also re-established the Ca2+ influx in DALNs as a response to dopamine (DA) stimuli under PQ2+/MB exposure. Because of its powerful antioxidant and antiapoptotic effects, CBD offers potential therapeutic utility in the treatment of PD.

α-Synuclein Attenuates Maneb Neurotoxicity through the Modulation of Redox-Sensitive Transcription Factors.

The accumulation and aggregation of α-synuclein is a pathognomonic sign of Parkinson's disease (PD). Maneb (MB) exposure has also been reported as one environmental triggering factor of this multifactorial neurodegenerative disease. In our laboratory, we have previously reported that mild overexpression of α-synuclein (200% increase with respect to endogenous neuronal levels) can confer neuroprotection against several insults. Here, we tested the hypothesis that α-synuclein can modulate the neuronal response against MB-induced neurotoxicity. When exposed to MB, cells with endogenous α-synuclein expression displayed increased reactive oxygen species (ROS) associated with diminished glutamate-cysteine ligase catalytic subunit (GCLc) and hemeoxygenase-1 (HO-1) mRNA expressions and upregulation of the nuclear factor erythroid 2-related factor 2 (NRF2) repressor, BTB domain and CNC homolog 1 (BACH1). We found that α-synuclein overexpression (wt α-syn cells) attenuated MB-induced neuronal damage by reducing oxidative stress. Decreased ROS found in MB-treated wt α-syn cells was associated with unaltered GCLc and HO-1 mRNA expressions and decreased BACH1 expression. In addition, the increased SOD2 expression and catalase activity were associated with forkhead box O 3a (FOXO3a) nuclear compartmentalization. Cytoprotective effects observed in wt α-syn cells were also associated with the upregulation of silent information regulator 1 (SIRT1). In control cells, MB-treatment downregulated glutathione peroxidase 4 mRNA levels, which was coincident with increased ROS content, lipid peroxidation, and mitochondrial alterations. These deleterious effects were prevented by ferrostatin-1, an inhibitor of ferroptosis, under conditions of endogenous α-synuclein expression. The overexpression of α-synuclein attenuated MB toxicity by the activation of the same mechanisms as ferrostatin-1. Overall, our findings suggest that mild overexpression of α-synuclein attenuates MB-induced neurotoxicity through the modulation of NRF2 and FOXO3a transcription factors and prevents cell death probably by intervening in mechanisms associated with ferroptosis. Thus, we postulate that early stages of α-synuclein overexpression could be potentially neuroprotective against MB neurotoxicity.

Integrin Mac1 mediates paraquat and maneb-induced learning and memory impairments in mice through NADPH oxidase-NLRP3 inflammasome axis-dependent microglial activation.

INTRODUCTION: The mechanisms of cognitive impairments in Parkinson's disease (PD) remain unknown. Accumulating evidence revealed that brain neuroinflammatory response mediated by microglial cells contributes to cognitive deficits in neuropathological conditions and macrophage antigen complex-1 (Mac1) is a key factor in controlling microglial activation. OBJECTIVES: To explore whether Mac1-mediated microglial activation participates in cognitive dysfunction in PD using paraquat and maneb-generated mouse PD model. METHODS: Cognitive performance was measured in wild type and Mac1-/- mice using Morris water maze test. The role and mechanisms of NADPH oxidase (NOX)-NLRP3 inflammasome axis in Mac1-mediated microglial dysfunction, neuronal damage, synaptic degeneration and phosphorylation (Ser129) of α-synuclein were explored by immunohistochemistry, Western blot and RT-PCR. RESULTS: Genetic deletion of Mac1 significantly ameliorated learning and memory impairments, neuronal damage, synaptic loss and α-synuclein phosphorylation (Ser129) caused by paraquat and maneb in mice. Subsequently, blocking Mac1 activation was found to mitigate paraquat and maneb-elicited microglial NLRP3 inflammasome activation in both in vivo and in vitro. Interestingly, stimulating activation of NOX by phorbol myristate acetate abolished the inhibitory effects of Mac1 blocking peptide RGD on paraquat and maneb-provoked NLRP3 inflammasome activation, indicating a key role of NOX in Mac1-mediated NLRP3 inflammasome activation. Furthermore, NOX1 and NOX2, two members of NOX family, and downstream PAK1 and MAPK pathways were recognized to be essential for NOX to regulate NLRP3 inflammasome activation. Finally, a NLRP3 inflammasome inhibitor glybenclamide abrogated microglial M1 activation, neurodegeneration and phosphorylation (Ser129) of α-synuclein elicited by paraquat and maneb, which were accompanied by improved cognitive capacity in mice. CONCLUSIONS: Mac1 was involved in cognitive dysfunction in a mouse PD model through NOX-NLRP3 inflammasome axis-dependent microglial activation, providing a novel mechanistic basis of cognitive decline in PD.

L-carnitine attenuates acoustic startle reflex dysfunction in adult male rats exposed to mancozeb.

The fungicide mancozeb increases oxygen-free radicals in the central nervous system. As an antioxidant, L-carnitine protects DNA and cell membranes from damage caused by oxygen-free radicals. The present study investigated how L-carnitine affected the acoustic startle response (ASR) in rats exposed to mancozeb. In this experimental study, male Wistar rats were gavaged orally with mancozeb (500, 1000, and 2000 mg/kg), L-carnitine (100, 200, and 400 mg/kg), or L-carnitine (200 mg/kg) + mancozeb (500 mg/kg) three times in 1 week. In the sham group, saline (0.9%, 10 mL/kg) was gavaged at a volume equivalent to that of the drugs. The control group did not receive any treatment. The results showed that locomotor activity and the percentage of prepulse inhibition in the mancozeb groups decreased compared to the sham group while these parameters increased in the L-carnitine group (200 mg/kg) compared to sham rats. In conclusion, mancozeb may increase the risk factor for cognitive diseases such as schizophrenia in people exposed to it while pretreatment with L-carnitine can attenuate the toxic effect.

Effective Management of Citrus Melanose Based on Combination of Ecofriendly Chemicals.

Citrus melanose, caused by the ascomycete fungus Diaporthe citri, is one of the most important diseases in China that affects not only the production but also the quality of citrus. In China, mancozeb is recommended to control melanose disease at the dose of 1.34 g/liter. However, it is widely applied in practice at the dose of 2.66 g/liter or even 4 g/liter, because reduced efficacy of the recommended dose was observed in regions severely damaged by melanose. In this study, some ecofriendly chemicals for melanose management were evaluated. First, the sensitivity to fungicides was screened in the laboratory based on the inhibition of mycelial growth and conidial germination of D. citri. Results showed that both quinone outside inhibitor (QoI) fungicides kresoxim-methyl and trifloxystrobin inhibited conidial germination of D. citri up to 100% at 0.1 µg/ml. The in vivo control efficacy on detached fruit indicated that treatments with elastic nanocopolymer film at 2 g/liter, mancozeb at 1 g/liter, and kresoxim-methyl at 0.1 g/liter significantly inhibited the infection process compared with the control treatment of mineral oil alone. In field trials, the efficacy of kresoxim-methyl at 0.1 g/liter and elastic nanocopolymer film at 2 g/liter mixed with mancozeb at 1 g/liter was equal to that of mancozeb at 2.66 g/liter. The use of mancozeb could be reduced greatly, and the newly developed fungicide combinations are more environmentally friendly due to the low toxicity of both QoI fungicides and elastic nanocopolymer film. The newly developed method with ecofriendly chemicals should play an important role in the management of citrus melanose in the future.

Exposure to dithiocarbamate fungicide maneb in vitro and in vivo: Neuronal apoptosis and underlying mechanisms.

Maneb, a widely-used dithiocarbamate fungicide, remains in the environment and exerts adverse health effects. Epidemiological evidence shows that maneb exposure is associated with a higher risk of Parkinson's disease (PD), one of the most common neurodegenerative diseases. However, the molecular mechanisms underlying maneb-induced neurotoxicity remain unclear. Here we investigated the toxic effects and the underlying mechanisms of maneb on the degeneration of dopaminergic cells and α-synuclein in A53T transgenic mice. In SH-SY5Y cells, exposure to maneb reduces cell viability, triggers neuronal apoptosis, induces mitochondrial dysfunction, and generates reactive oxidative species (ROS) in a dose-dependent manner. Furthermore, Western blot analysis found that the mitochondrial apoptosis pathway (Bcl-2, Bax, cytochrome c, activated caspase-3) and the PKA/CREB signaling pathway (PKA, PDE10A, CREB, p-CREB) were changed by maneb both in vitro and in vivo. In addition, the activation of the mitochondrial apoptosis pathway induced by maneb was attenuated by activating PKA. Therefore, these results suggest that the PKA/CREB signaling pathway is involved in maneb-induced apoptosis. This study provides novel insights into maneb-induced neurotoxicity and the underlying mechanisms, which may serve as a guide for further toxicological assessment and standard application of maneb.

Mancozeb induces nephrotoxicity by impairing the oxidative phosphorylation pathway: A transcriptome study.

This study analyzed the mechanism underlying mancozeb (MCZ)-induced kidney injury by detecting kidney function indicators, combined with transcriptome and metabolome sequencing. Twenty mice were randomly assigned into two groups (control and MCZ groups) to explore the MCZ-induced kidney toxicity. The control group was gavaged with 0.2 mL of deionized water, and the MCZ group with 0.2 mL of 100 mg/kg MCZ for 30 days. The kidney structure of the MCZ group was damaged, with slight hyaline degeneration in the kidney tubular epithelial envelope. The creatinine (CRE) and uric acid (UA) were significantly increased in the MCZ group than in the control group. Moreover, the reactive oxygen species (ROS) significantly accumulated in the MCZ group kidneys. Compared to the control group, superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were significantly decreased in the MCZ group, while the MDA content was substantially increased. The differentially expressed genes (DEGs) in the MCZ group were mainly enriched in the oxidative phosphorylation pathway. Besides, in the MCZ group, ndufs1 and ndufab1 genes were significantly up-regulated, while cox5b, ndufa5, and ndufa6 genes were significantly down-regulated, consistent with the PCR verification results. The metabolomic analysis identified cGMP-PKG signaling pathway of MCZ-induced nephrotoxicity, with Guanosine monophosphate and Adenosine 5'-monophosphate as the main altered metabolites. These results indicated that MCZ impairs the mice kidneys by obstructing the oxidative phosphorylation pathway, which increases oxidative stress in the kidneys, resulting in kidney injury.

Assessment of Mancozeb Exposure, Absorbed Dose, and Oxidative Damage in Greenhouse Farmers.

Mancozeb (MNZ) is a fungicide commonly employed in many countries worldwide. This study assesses MNZ absorption dynamics in 19 greenhouse farmers, specifically following dermal exposure, aiming to verify the efficacy of both preventive actions and protective equipment. For data collection, a multi-assessment approach was used, which included a survey to record study population features. MNZ exposure was assessed through the indirect measurement of ethylene thiourea (ETU), widely employed as an MNZ biomarker. The ETU concentration was measured with the patch method, detecting environmental ETU trapped in filter paper pads, applied both on skin and working clothes, during the 8 h work shift. Urine and serum end-of-shift samples were also collected to measure ETU concentrations and well-known oxidative stress biomarkers, respectively, namely reactive oxygen metabolites (ROMs), advanced oxidation protein products (AOPPs), and biological antioxidant potential (BAP). It was observed that levels of ETU absorbed and ETU excreted were positively correlated. Additionally, working clothes effectively protected workers from MNZ exposure. Moreover, following stratification of the samples based on the specific working duty (i.e., preparation and spreading of MNZ and manipulation of MNZ-treated seedlings), it was found that the spreading group had higher ETU-related risk, despite lower chronic exposure levels. AOPP and ROM serum levels were higher in MNZ-exposed subjects compared with non-exposed controls, whereas BAP levels were significantly lower. Such results support an increase in the oxidative stress upon 8 h MNZ exposure at work. In particular, AOPP levels demonstrated a potential predictive role, as suggested by the contingency analysis results. Overall, this study, although conducted in a small group, confirms that ETU detection in pads, as well as in urine, might enable assessment of the risk associated with MNZ exposure in greenhouse workers. Additionally, the measurement of circulating oxidative stress biomarkers might help to stratify exposed workers based on their sensitivity to MNZ. Pivotally, the combination of both ETU measurement and biological monitoring might represent a novel valuable combined approach for risk assessment in farmhouse workers exposed to pesticides. In the future, these observations will help to implement effective preventive strategies in the workplace for workers at higher risk, including greenhouse farmers who are exposed to pesticides daily, as well as to clarify the occupational exposure levels to ETU.

Exposure to the environmentally toxic pesticide maneb induces Parkinson's disease-like neurotoxicity in mice: A combined proteomic and metabolomic analysis.

Maneb is a typical dithiocarbamate fungicide that has been extensively used worldwide. Epidemiological evidence shows that exposure to maneb is an environmental risk factor for Parkinson's disease (PD). However, the mechanisms underlying maneb-induced neurotoxicity have yet to be elucidated. In this study, we exposed SH-SY5Y cells to maneb at environmentally relevant concentrations (0, 0.1, 5, 10 mg/L) and found that maneb dose-dependently decreased the cell viability. Furthermore, maneb (60 mg/kg) induced PD-like motor impairment in α-synuclein A53T transgenic mice. The results of tandem mass tag (TMT) proteomics and metabolomics studies of mouse brain and serum revealed significant changes in proteins and metabolites in the pathways involved in the neurotransmitter system. The omics results were verified by targeted metabolomics and Western blot analysis, which demonstrated that maneb induced disturbance of the PD-related pathways, including the phenylalanine and tryptophan metabolism pathways, dopaminergic synapse, synaptic vesicle cycle, mitochondrial dysfunction, and oxidative stress. In addition, the PD-like phenotype induced by maneb was attenuated by the asparagine endopeptidase (AEP) inhibitor compound #11 (CP11) (10 mg/kg), indicating that AEP may play a role in maneb-induced neurotoxicity. To the best of our knowledge, this is the first study to investigate the molecular mechanisms underlying maneb-induced PD-like phenotypes using multiomics analysis, which identified novel therapeutic targets for PD associated with pesticides and other environmental pollutants.

Cyclooxygenase-2 activates the free radical-mediated apoptosis of polymorphonuclear leukocytes in the maneb- and paraquat-intoxicated rats.

Overproduction of free radicals and inflammation could lead to maneb (MB)- and paraquat (PQ)-induced toxicity in the polymorphonuclear leukocytes (PMNs). Cyclooxygenase-2 (COX-2), an inducible COX, is imperative in the pesticides-induced pathological alterations. However, its role in MB- and PQ-induced toxicity in the PMNs is not yet clearly deciphered. The current study explored the contribution of COX-2 in MB- and PQ-induced toxicity in the PMNs and the mechanism involved therein. Combined MB and PQ augmented the production of free radicals, lipid peroxides and activity of superoxide dismutase (SOD) in the rat PMNs. While combined MB and PQ elevated the expression of COX-2 protein, activation of nuclear factor-kappa B (NF-κB) and phosphorylation of c-Jun N-terminal kinase (JNK), release of mitochondrial cytochrome c and levels of procaspase-3/9 were attenuated in the PMNs. Celecoxib (CXB), a COX-2 inhibitor, ameliorated the combined MB and PQ-induced modulations in the PMNs. MB and PQ augmented the free radical generation, COX-2 protein expression, NF-κB activation and JNK phosphorylation and reduced the cell viability of cultured rat PMNs and human leukemic HL60. MB and PQ elevated mitochondrial cytochrome c release and poly (ADP-ribose) polymerase cleavage whilst procaspase-3/9 levels were attenuated in the cultured PMNs. MB and PQ also increased the levels of phosphorylated c-jun and caspase-3 activity in the HL60 cells. CXB; SP600125, a JNK-inhibitor and pyrrolidine dithiocarbamate (PDTC), a NF-κB inhibitor, rescued from MB and PQ-induced changes in the PMNs and HL60 cells. However, CXB offered the maximum protection among the three. The results show that COX-2 activates apoptosis in the PMNs following MB and PQ intoxication, which could be linked to NF-κB and JNK signaling.

Transcriptomics and metabolomics revealed the molecular mechanism of the toxic effect of mancozeb on liver of mice.

Mancozeb (MCZ), a broad-spectrum fungicide, has been widely used in crops (tomatoes and potatoes) in the past few decades, resulting in its bioaccumulation in the food web. However, the mechanism of MCZ on liver injury has not been reported yet. This study combined transcriptomics and metabolomics to explore the potential mechanism of MCZ on liver injury. MCZ group was given 100 mg/kg MCZ every day, and the C group was given 0.2 mL of deionized water every day. One hundred mg/kg MCZ led to unclear hepatocyte structure and hemorrhagic inflammatory cell infiltration. Transcriptomics and metabolomics analyses showed that the MCZ group resulted in 326 differentially expressed genes (DEGs) and 179 differential metabolites. Joint analysis showed that DEGs and differential metabolites were mainly enriched in the adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway. We found that MCZ could increase the content of reactive oxygen species (ROS) and reduce the activities of superoxide dismutase (SOD) and catalase (CAT). The contents of DNA methyltransferases (DNMT1, DNMT3A, and DNMT3B) in the liver decreased significantly, and the state of DNA methylation was significantly higher than the control (C) group (p < 0.05). Our results suggest that AMPK and mitogen­activated protein kinase (MAPK) signaling pathways play an important role in MCZ-induced liver injury and are the key mechanisms for understanding the hepatotoxicity of MCZ.

Neurotoxicity of pesticides - A link to neurodegeneration.

Parkinson's disease (PD) is a neurodegenerative disorder which mainly targets motor symptoms such as tremor, rigidity, bradykinesia and postural instability. The physiological changes occur due to dopamine depletion in basal ganglia region of the brain. PD aetiology is not yet elucidated clearly but genetic and environmental factors play a prominent role in disease occurrence. Despite of various environmental factors, pesticides exposure has been convicted as major candidate in PD pathogenesis. Among various pesticides 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) has been widely investigated in PD following with paraquat (PQ), maneb (MB), organochlorines (OC) and rotenone. Effect of these pesticides has been suggested to be involved in oxidative stress, alterations in dopamine transporters, mitochondrial dysfunction, α-synuclein (αSyn) fibrillation, and neuroinflammation in PD. The present review discusses the influence of pesticides in neurodegeneration and its related epidemiological studies conducted in PD. Furthermore, we have deliberated the common pesticides involved in PD and its associated genetic alterations and the probable mechanism of them behind PD pathogenesis. Hence, we conclude that pesticides play a prominent role in PD pathogenesis and advance research is needed to investigate the alterations in genetic and mechanistic aspects of PD.

Nematode Community of a Natural Grassland Responds Sensitively to the Broad-Spectrum Fungicide Mancozeb in Soil Microcosms.

Fungicides make up the largest part of total pesticide use, with the dithiocarbamate mancozeb being widely applied as a nonsystemic contact pesticide to protect a wide range of field crops against fungal diseases. Although nematodes are key drivers of soil functioning, data on effects of fungicides, and especially mancozeb, on these nontarget organisms are scarce. Therefore, the effects of mancozeb on a soil nematode community from a natural grassland were assessed in small-scale soil microcosms. Nematodes were exposed to mancozeb-spiked soil in six nominal concentrations (7-133 mg/kg dry soil) and analyzed after 14, 56, and 84 days in terms of densities, genus composition, and functional traits. Because this fungicide is known to quickly degrade in soils (50% degradation time <1 day), mancozeb concentrations were analyzed for all sampling occasions. Chemical analysis revealed considerably lower measured concentrations compared with the aimed nominal soil concentrations at the beginning of the exposure (1-18 mg/kg dry soil), suggesting fast degradation during the spiking process. Nevertheless, the native nematode community responded sensitively to the fungicide mancozeb, revealing lower no-observed-effect concentration and 10% effect concentration (EC10) values than reported for other soil invertebrates such as springtails and earthworms. Using the EC10 for the most sensitive nematode community endpoint (percentage of predators and omnivores: 1.2 mg/kg dry soil), the risk assessment exhibited a toxicity exposure ratio of 0.66 and, thus, a high risk of mancozeb for soil nematodes. Keeping in mind their abundance and their central roles in soil food-web functioning, the demonstrated sensitivity to a widely applied fungicide underscores the relevance of the inclusion of nematodes into routine risk-assessment programs for pesticides. Environ Toxicol Chem 2022;41:2420-2430. © 2022 SETAC.