Mancozeb affects mitochondrial activity, redox status and ATP production in mouse granulosa cells

Horizontal mitochondrial transfer as a novel bioenergetic tool for mesenchymal stromal/stem cells: molecular mechanisms and therapeutic potential in a variety of diseases

Intercellular mitochondrial transfer (MT) is a newly discovered form of cell-to-cell signalling involving the active incorporation of healthy mitochondria into stressed/injured recipient cells, contributing to the restoration of bioenergetic profile and cell viability, reduction of inflammatory processes and normalisation of calcium dynamics. Recent evidence has shown that MT can occur through multiple cellular structures and mechanisms: tunneling nanotubes (TNTs), via gap junctions (GJs), mediated by extracellular vesicles (EVs) and other mechanisms (cell fusion, mitochondrial extrusion and migrasome-mediated mitocytosis) and in different contexts, such as under physiological (tissue homeostasis and stemness maintenance) and pathological conditions (hypoxia, inflammation and cancer). As Mesenchimal Stromal/ Stem Cells (MSC)-mediated MT has emerged as a critical regulatory and restorative mechanism for cell and tissue regeneration and damage repair in recent years, its potential in stem cell therapy has received increasing attention. In particular, the potential therapeutic role of MSCs has been reported in several articles, suggesting that MSCs can enhance tissue repair after injury via MT and membrane vesicle release. For these reasons, in this review, we will discuss the different mechanisms of MSCs-mediated MT and therapeutic effects on different diseases such as neuronal, ischaemic, vascular and pulmonary diseases. Therefore, understanding the molecular and cellular mechanisms of MT and demonstrating its efficacy could be an important milestone that lays the foundation for future clinical trials.

Effects of glyphosate, mancozeb and their combinations on mouse neuroblastoma cells

Pesticides-related toxicities have long been studied. Data regarding the effects of combined exposure to environmentally relevant pesticides however remain lacking. The herbicide glyphosate and the fungicide mancozeb are extensively used in agriculture. Residues of both compounds are frequently found in food and water and therefore, environmental exposure to both pesticides is a possibility. Neurotoxicity of glyphosate, mancozeb and their combinations were investigated using mouse neuroblastoma cells. Cytotoxicity observed with the glyphosate and mancozeb combinations was higher than that observed when glyphosate was tested alone. Combinations of glyphosate followed by mancozeb increased copper, manganese, and zinc levels. Mixture of mancozeb + glyphosate increased manganese and zinc levels. Combination of mancozeb followed by glyphosate increased copper and zinc levels. Glutathione ratio was decreased as a result of combinations of glyphosate and mancozeb. The decrease in glutathione ratio was greater in the combination groups than in glyphosate alone.

Analysis of the spatial distribution of amyotrophic lateral sclerosis in Virginia

Objective: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder that is usually fatal. Environmental exposures have been posited in the etiology of ALS, but few studies have modeled the spatial risk of ALS over large geographic areas. In this paper, our goal was to analyze the spatial distribution of ALS in Virginia and identify any areas with significantly elevated risk using Virginia ALS Association administrative data. Methods: We used Bayesian hierarchical spatial regression models to estimate the relative risk for ALS in Virginia census tracts, adjusting for several covariates posited to be associated with the disease. We used an intrinsic conditional autoregressive prior to allow for spatial correlation in the risk estimates and stabilize estimates over space. Results: Considerable variation in ALS risk existed across Virginia, with greater relative risk found in the central and western parts of the state. We identified significantly elevated relative risk in a number of census tracts. In particular, Henrico, Albemarle, and Botetourt counties all contained at least four census tracts with significantly elevated risk. Conclusions: We identified several areas with significantly elevated ALS risk across Virginia census tracts. These results can inform future studies of potential environmental triggers for the disease, whose etiology is still being understood.

Mancozeb-induced cytotoxicity in human erythrocytes: enhanced generation of reactive species, hemoglobin oxidation, diminished antioxidant power, membrane damage and morphological changes

Mancozeb is an ethylene bis-dithiocarbamate fungicide extensively used in agriculture to safeguard crops from various fungal diseases. The general population is exposed to mancozeb through consumption of contaminated food or water. Here, we have investigated the effect of mancozeb on isolated human erythrocytes under in vitro conditions. Erythrocytes were treated with different concentrations of mancozeb (0, 5, 10, 25, 50, 100 μM) and incubated for 24 h at 37 °C. Analysis of biochemical parameters and cell morphology showed dose-dependent toxicity of mancozeb in human erythrocytes. Mancozeb treatment caused hemoglobin oxidation and heme degradation. Protein and lipid oxidation were enhanced, while a significant decrease was seen in reduced glutathione and total sulfhydryl content. A significant increase in the generation of reactive oxygen and nitrogen species was detected in mancozeb-treated erythrocytes. The antioxidant capacity and the activity of key antioxidant enzymes were greatly diminished, while crucial metabolic pathways were inhibited in erythrocytes. Damage to the erythrocyte membrane on mancozeb treatment was apparent from increased cell lysis and osmotic fragility, along with the impairment of the plasma membrane redox system. Mancozeb also caused morphological alterations and transformed the normal discoid-shaped erythrocytes into echinocytes and stomatocytes. Thus, mancozeb induces oxidative stress in human erythrocytes, impairs the antioxidant defense system, oxidizes cellular components, that will adversely affect erythrocyte structure and function.

Effects of Nelumbonucifera Gaertn. Petal Tea Extract on Hepatotoxicity and Oxidative Stress Induced by Mancozeb in Rat Model

Mancozeb (Mz) is one of the most widely used pesticides that has been reported to cause adverse human health risks. White Nelumbo nucifera (N. nucifera) petals have therapeutic properties to prevent toxicity. Hence, this study attempted to determine the effects of N. nucifera extract on hepatotoxicity and oxidative stress in mancozeb-treated rats. Seventy-two male rats were divided into nine groups and designed with a control; N. nucifera extract was administered at the doses of 0.55, 1.1, and 2.2 mg/kg bw/day, Mz was administered at 500 mg/kg bw/day, and the co-treatment groups (N. nucifera and Mz) were administered 0.55, 1.1, and 2.2 mg/kg bw/day of N. nucifera followed by administering Mz 500 mg/kg bw/day daily for 30 days. The results showed that all doses of N. nucifera extract did not induce hepatic toxicity and could suppress the toxicity of mancozeb by increasing body weight gain and decreasing relative liver weight, lobular inflammation, and total injury score. The combination treatment also decreased the molecular markers of oxidative stress (2-hydroxybutyric acid, 4-hydroxynonenal, l-tyrosine, pentosidine, and N6-carboxymethyllysine). Furthermore, the reduced glutathione and oxidized glutathione contents were adjusted close to the normal level. Therefore, N. nucifera extract is a natural antioxidant supplement that could decrease the toxicity of mancozeb and can be safely consumed.

Ultrastructural Evaluation of Mouse Oocytes Exposed In Vitro to Different Concentrations of the Fungicide Mancozeb

Mancozeb is a widely used fungicide, considered to be an endocrine disruptor. In vivo and in vitro studies evidenced its reproductive toxicity on mouse oocytes by altering spindle morphology, impairing oocyte maturation, fertilization, and embryo implantation. Mancozeb also induces dose-dependent toxicity on the ultrastructure of mouse granulosa cells, including chromatin condensation, membrane blebbing, and vacuolization. We evaluated the effects on the ultrastructure of mouse oocytes isolated from cumulus-oocyte complexes (COCs), exposed in vitro to increasing concentrations of mancozeb. COCs were matured in vitro with or without (control) low fungicide concentrations (0.001-1 μg/mL). All mature oocytes were collected and prepared for light and transmission electron microscopy. Results showed a preserved ultrastructure at the lowest doses (0.001-0.01 μg/mL), with evident clusters of round-to-ovoid mitochondria, visible electron-dense round cortical granules, and thin microvilli. Mancozeb concentration of 1 μg/mL affected organelle density concerning controls, with a reduction of mitochondria, appearing moderately vacuolated, cortical granules, and microvilli, short and less abundant. In summary, ultrastructural data revealed changes mainly at the highest concentration of mancozeb on mouse oocytes. This could be responsible for the previously described impaired capability in oocyte maturation, fertilization, and embryo implantation, demonstrating its impact on the reproductive health and fertility.

Pre-imaginal exposure to mancozeb induces morphological and behavioral deficits and oxidative damage in Drosophila melanogaster

Mancozeb (MZ), a manganese/zinc containing ethylene-bis-dithiocarbamate, is a broad-spectrum fungicide. Chronic exposure to MZ has been related to several organisms' neurological, hormonal, and developmental disorders. However, little is known about the post-natal effects of developmental exposure to MZ. In this study, Drosophila melanogaster was subjected to a pre-imaginal (eggs-larvae-pupae stage) model of exposure to MZ at 0.1 and 0.5 mg/mL. The emergence rate, body size, locomotor performance, sleep patterns, and molecular and biochemical parameters were evaluated in post-emerged flies. Results demonstrate that pre-imaginal exposure to MZ significantly impacted early emerged flies. Additionally, reduced progeny viability, smaller body size and delaying in emergence period, locomotor impairment, and prolonged sleep time were observed. Content of glucose, proteins, and triglycerides were altered, and the bioenergetics efficiency and oxidative phosphorylation at complex I were inhibited. mRNA stade state levels of genes responsive to stress, metabolism, and regulation of circadian cycle (Nrf2, p38, Hsp83, Akt1, GPDH, tor, per, tim, dILP2, and dILP6) were augmented, pointing out to stimulation of antioxidant defenses, insulin-dependent signaling pathway activation, and disruption of sleep regulation. These data were followed by increased lipid peroxidation and lower glutathione levels. In addition, the activity of catalase and glutathione-S-transferase were induced, whereas superoxide dismutase was inhibited. Together, these results demonstrate that developmental exposure to MZ formulation led to phenotype and behavioral alterations in young flies, possibly related to disruption of energetic metabolism, oxidative stress, and deregulation of genes implied in growth, sleep, and metabolism.

Neuroprotective Effect of Vitamin D on Behavioral and Oxidative Parameters of Male and Female Adult Wistar Rats Exposed to Mancozeb (manganese/zinc ethylene bis-dithiocarbamate)

The constant exposure of rural workers to pesticides is a serious public health problem. Mancozeb (MZ) is a pesticide  linked to hormonal, behavioral, genetic, and neurodegenerative effects, mainly related to oxidative stress. Vitamin D is a promising molecule that acts as a protector against brain aging. This study aimed to evaluate the neuroprotective role of vitamin D in adult male and female Wistar rats exposed to MZ. Animals received 40 mg/kg of MZ i.p. and 12.5 μg/kg or 25 μg/kg vitamin D by gavage, twice a week, for 6 weeks. The concentration of manganese had a significant increase in the hippocampus of both sexes and in the striatum of females, unlike zinc, which did not show a significant increase. MZ poisoning led to mitochondrial changes in brain tissues and promoted anxiogenic effects, especially in females. Alterations in antioxidant enzymes, mainly in the catalase activity were observed in intoxicated rats. Taken together, our results showed that exposure to MZ leads to the accumulation of manganese in brain tissues, and the behavior and metabolic/oxidative impairment were different between the sexes. Furthermore, the administration of Vitamin D was effective in preventing the damage caused by the pesticide.

Cytotoxicity, Mitochondrial Functionality, and Redox Status of Human Conjunctival Cells after Short and Chronic Exposure to Preservative-Free Bimatoprost 0.03% and 0.01%: An In Vitro Comparative Study

Prostaglandin analogues (PGAs), including bimatoprost (BIM), are generally the first-line therapy for glaucoma due to their greater efficacy, safety, and convenience of use. Commercial solutions of preservative-free BIM (BIM 0.03% and 0.01%) are already available, although their topical application may result in ocular discomfort. This study aimed to evaluate the in vitro effects of preservative-free BIM 0.03% vs. 0.01% in the human conjunctival epithelial (HCE) cell line. Our results showed that long-term exposure to BIM 0.03% ensues a significant decrease in cell proliferation and viability. Furthermore, these events were associated with cell cycle arrest, apoptosis, and alterations of ΔΨ_m. BIM 0.01% does not exhibit cytotoxicity, and no negative influence on conjunctival cell growth and viability or mitochondrial activity has been observed. Short-time exposure also demonstrates the ability of BIM 0.03% to trigger reactive oxygen species (ROS) production and mitochondrial hyperpolarisation. An in silico drug network interaction was also performed to explore known and predicted interactions of BIM with proteins potentially involved in mitochondrial membrane potential dissipation. Our findings overall strongly reveal better cellular tolerability of BIM 0.01% vs. BIM 0.03% in HCE cells.

Multi-Target Effects of ß-Caryophyllene and Carnosic Acid at the Crossroads of Mitochondrial Dysfunction and Neurodegeneration: From Oxidative Stress to Microglia-Mediated Neuroinflammation

Inflammation and oxidative stress are interlinked and interdependent processes involved in many chronic diseases, including neurodegeneration, diabetes, cardiovascular diseases, and cancer. Therefore, targeting inflammatory pathways may represent a potential therapeutic strategy. Emerging evidence indicates that many phytochemicals extracted from edible plants have the potential to ameliorate the disease phenotypes. In this scenario, ß-caryophyllene (BCP), a bicyclic sesquiterpene, and carnosic acid (CA), an ortho-diphenolic diterpene, were demonstrated to exhibit anti-inflammatory, and antioxidant activities, as well as neuroprotective and mitoprotective effects in different in vitro and in vivo models. BCP essentially promotes its effects by acting as a selective agonist and allosteric modulator of cannabinoid type-2 receptor (CB2R). CA is a pro-electrophilic compound that, in response to oxidation, is converted to its electrophilic form. This can interact and activate the Keap1/Nrf2/ARE transcription pathway, triggering the synthesis of endogenous antioxidant “phase 2” enzymes. However, given the nature of its chemical structure, CA also exhibits direct antioxidant effects. BCP and CA can readily cross the BBB and accumulate in brain regions, giving rise to neuroprotective effects by preventing mitochondrial dysfunction and inhibiting activated microglia, substantially through the activation of pro-survival signalling pathways, including regulation of apoptosis and autophagy, and molecular mechanisms related to mitochondrial quality control. Findings from different in vitro/in vivo experimental models of Parkinson’s disease and Alzheimer’s disease reported the beneficial effects of both compounds, suggesting that their use in treatments may be a promising strategy in the management of neurodegenerative diseases aimed at maintaining mitochondrial homeostasis and ameliorating glia-mediated neuroinflammation.

Synergistic Activity of Ketoconazole and Miconazole with Prochloraz in Inducing Oxidative Stress, GSH Depletion, Mitochondrial Dysfunction, and Apoptosis in Mouse Sertoli TM4 Cells

Triazole and imidazole fungicides represent an emerging class of pollutants with endocrine-disrupting properties. Concerning mammalian reproduction, a possible causative role of antifungal compounds in inducing toxicity has been reported, although currently, there is little evidence about potential cooperative toxic effects. Toxicant-induced oxidative stress (OS) may be an important mechanism potentially involved in male reproductive dysfunction. Thus, to clarify the molecular mechanism underlying the effects of azoles on male reproduction, the individual and combined potential of fluconazole (FCZ), prochloraz (PCZ), miconazole (MCZ), and ketoconazole (KCZ) in triggering in vitro toxicity, redox status alterations, and OS in mouse TM4 Sertoli cells (SCs) was investigated. In the present study, we demonstrate that KCZ and MCZ, alone or in synergistic combination with PCZ, strongly impair SC functions, and this event is, at least in part, ascribed to OS. In particular, azoles-induced cytotoxicity is associated with growth inhibitory effects, G0/G1 cell cycle arrest, mitochondrial dysfunction, reactive oxygen species (ROS) generation, imbalance of the superoxide dismutase (SOD) specific activity, glutathione (GSH) depletion, and apoptosis. N-acetylcysteine (NAC) inhibits ROS accumulation and rescues SCs from azole-induced apoptosis. PCZ alone exhibits only cytostatic and pro-oxidant properties, while FCZ, either individually or in combination, shows no cytotoxic effects up to 320 µM.

Analytical and toxicological aspects of dithiocarbamates: an overview of the last 10 years

Compilation studies related to toxicological aspects and also biological monitoring and analysis methods for specific fungicides and, mainly, those that belong to the class of the dithiocarbamates (DTCs) have not been carried out at least in the last ten years. DTCs - dimethyldithiocarbamates, ethylenebisditiocarbamates, propylenebisditiocarbamates - are organosulfur compounds that form complexes due to the presence of different chemical elements, which bind strongly and inhibit enzymes that are essential to the functioning of the organism, causing a serious proven adverse effect on biological systems, such as alteration of thyroid hormones, teratogenesis and neurotoxicity. It is still evident, as shown by world data, that the growing consumption of fungicides has increasingly exposed the population in general and, in particular, workers who deal with these substances. There is a scarcity of studies in the literature discussing the toxicological and analytical aspects that are important for understanding the real effects of DTCs and monitoring human exposure to them. Therefore, the aim of this work was to expose, in a comprehensive way and through a narrative review, the negligence of research related to the fungicides of the DTCs class, their metabolites, as well as the toxicological and analytical aspects involved. The review is divided into two parts: (1) Toxicological aspects, including toxicokinetics, toxicodynamics and toxidromes; and (2) Analytical Toxicology, which comprises biomarkers, sample preparation and identification/quantification methods.

In vivo and in vitro postovulatory aging: when time works against oocyte quality?

In mammalian species an optimal fertilization window during which successful fertilization occurs. In the majority of mammals estrus marks ovulation time and coincident with mating, thereby allowing the synchronized meeting in the fallopian tubes, between freshly ejaculated sperm and freshly ovulated oocytes. Conversely, women do not show natural visual signs of ovulation such that fertilization can occur hours later involving an aged oocyte and freshly ejaculated spermatozoa. During this time, the oocyte undergoes a rapid degradation known as “postovulatory aging” (POA). POA may become particularly important in the human-assisted reproductive technologies, as the fertilization of retrieved mature oocytes can be delayed due to increased laboratory workload or because of unforeseeable circumstances, like the delayed availability of semen samples. This paper is an updated review of the consequences of POA, either in vivo or in vitro, on oocyte quality with particular attention to modifications caused by POA on oocyte nuclear, cytoplasmic, genomic, and epigenetic maturation, and embryo development.

Pesticides applied to crops and amyotrophic lateral sclerosis risk in the U.S

BACKGROUND

Environmental exposures are implicated in the etiology of amyotrophic lateral sclerosis (ALS). Application of insecticides, herbicides, and fungicides with neurotoxic properties to crops is permitted in the U.S., however reporting of the quantities is government mandated.

OBJECTIVE

To identify pesticides that may be associated with ALS etiology for future study.

METHODS

We geospatially estimated exposure to crop-applied pesticides as risk factors for ALS in a large de-identified medical claims database, the SYMPHONY Integrated Dataverse®. We extracted residence at diagnosis of ∼26,000 nationally distributed ALS patients, and matched non-ALS controls. We mapped county-level U.S. Geological Survey data on applications of 423 pesticides to estimate local residential exposure. We randomly broke the SYMPHONY dataset into two groups to form independent discovery and validation cohorts, then confirmed top hits using residential history information from a study of NH, VT, and OH.

RESULTS

Pesticides with the largest positive statistically significant associations in both the discovery and the validation studies and evidence of neurotoxicity in the literature were the herbicides 2,4-D (OR 1.25 95 % CI 1.17-1.34) and glyphosate (OR 1.29 95 %CI 1.19-1.39), and the insecticides carbaryl (OR 1.32 95 %CI 1.23-1.42) and chlorpyrifos (OR 1.25 95 %CI 1.17-1.33).

SIGNIFICANCE

Our geospatial analysis results support potential neurotoxic pesticide exposures as risk factors for sporadic ALS. Focused studies to assess these identified potential relationships are warranted.

Toxicological Comparison of Mancozeb and Zoxamide Fungicides at Environmentally Relevant Concentrations by an In Vitro Approach

Mancozeb (MZ) and zoxamide (ZOX) are fungicides commonly used in pest control programs to protect vineyards. Their toxic and genotoxic potential were investigated in vitro on HepG2 and A549 cell lines at environmentally relevant concentrations. Cytotoxicity, apoptosis, necrosis and intracellular reactive oxygen species (ROS), comet assay and a micronucleus test with CREST immunofluorescence were used. The expression of a panel of genes involved in apoptosis/necrosis (BAX/BCL2), oxidative stress (NRF2), drug metabolism (CYP1A1) and DNA repair (ERCC1/OGG1) was evaluated by real-time PCR. Both fungicides were cytotoxic at the highest tested concentrations (295.7 and 463.4 µM, respectively); MZ induced necrosis, ZOX did not increase apoptosis but modulated BAX and BCL2 expression, suggesting a different mechanism. Both compounds did not increase ROS, but the induction of CYP1A1 and NRF2 expression supported a pro-oxidant mechanism. The comet assay evidenced MZ genotoxicity, whereas no DNA damage due to ZOX treatment was observed. Positive micronuclei were increased in both cell lines treated with MZ and ZOX, supporting their aneugenic potential. ERCC1 and OGG1 were differently modulated, indicating the efficient activation of the nucleotide excision repair system by both fungicides and the inhibition of the base excision repair system by MZ. Overall, MZ confirmed its toxicity and new ZOX-relevant effects were highlighted.

Impairment of caprine oocyte maturation in vitro and alteration of granulosa cells functions by widely used fungicide mancozeb

Mancozeb is classified as an endocrine disruptor; thus the present study was carried out to investigate the impact of mancozeb on mammalian ovarian functions using in vitro caprine oocyte maturation and granulosa cell culture models. Caprine cumulus oocyte complexes (COCs) and granulosa cells were cultured under standard culture conditions and treated with mancozeb concentrations of 0.3, 3, and 30 μg/ml along with a control for 24 h and assessed. Granulosa cell viability and progesterone concentration in spent culture media after treatments were also assessed. Mancozeb significantly decreased (P < 0.05) the oocytes cumulus expansion and the maturation of caprine oocytes. Marked changes in granulose cell morphology were observed with 30 μg/ml mancozeb and significantly reduced (P < 0.05) cell viability. Interestingly, the same concentrations significantly increased (P < 0.05) the progesterone secretion by the cells. Significant reduction of granulosa cells viability and reduction of cumulus expansion and suppression of metaphase plate formation in oocyte can impair the fertilization ability and developmental potential of the oocytes. High progesterone concentration due to mancozeb treatment may suppress LH surge and suppress ovulation. In conclusion, mancozeb suppresses granulosa cells viability, reduces cumulus expansion, and suppresses metaphase plate formation but induces progesterone secretion from granulosa cells that may inhibit LH surge for ovulation process.

Lactobacillus sakei Pro-Bio65 Reduces TNF-α Expression and Upregulates GSH Content and Antioxidant Enzymatic Activities in Human Conjunctival Cells

Purpose

The study investigates the regulatory effects exhibited by lysate of Lactobacillus sakei pro-Bio65 (4%; L.SK) on the human conjunctival epithelial (HCE) cell line.

Methods

Trypan blue and methylthiazol tetrazolium (MTT) methods were used to assess cell growth and viability. Mitochondrial membrane potential was assessed by JC-1 staining and cytofluorimetric detection methods. The antioxidant pattern and the intracellular reactive oxygen species (ROS) levels were analyzed by spectrophotometric and spectrofluorimetric methods. NF-κB luciferase activity was quantified by luminometric detection. NF-κB nuclear translocation, as well as mitochondrial morphology, were investigated by immunofluorescence using confocal microscopy. Cytokines and COX2 expression levels were determined by Western blot analyses.

Results

This study demonstrates that L.SK exposure does not influence HCE cell proliferation and viability in vitro. L.SK paraprobiotic induces mild-low levels of intracellular ROS. It is coupled to changes in the mitochondrial membrane potential (ΔΨm), in a context of a regular mitochondrial-network organization. The negative modulation of tumor necrosis factor alpha (TNF-α) expression levels and rising antioxidant defense efficiency, mediated by the upregulation of glutathione (GSH) and increased antioxidant enzymatic activities, were observed.

Conclusions

This study demonstrates that L.SK empowers the antioxidant endogenous efficiency of HCE cells, by the upregulation of the GSH content and the enzymatic antioxidant pattern, and concurrently reduces TNF-α protein expression.

Translational Relevance

Although the obtained in vitro results should be confirmed by in vivo investigations, our data suggest the possibility of L.SK paraprobiotic application for promoting eye health, exploring its use as an endogen antioxidant system inducer in preventing and treating different oxidative stress-based, inflammatory, and age-related conditions.

Disruption of mitochondrial complexes, cytotoxicity, and apoptosis results from Mancozeb exposure in transformed human colon cells

Ethylene bisdithiocarbamate pesticides, including Mancozeb (MZ), are used as fungicides. Effects of MZ on apoptosis induction and mitochondrial activity of HT-29 colon cells were investigated. MZ exposed cells exhibited blebbing and cellular membrane disruption in scanning electron micrographs. Positive fluorescent staining with Annexin V at doses of 60-140 μM supports apoptosis as the mechanism of cell death. Activity of all electron transport chain complexes were evaluated. Mitochondrial Complex I activity was decreased in 100 μM treated cells. Mitochondrial Complex III activity was decreased in 60 and 100 μM MZ treated cells. Mitochondrial Complex II and Complex IV activities were decreased in cells treated with 60, 100, and 140 μM. Cells treated with 60 μM exhibited a decrease in Complex V enzyme activity. It is concluded that MZ exposure inhibits all mitochondrial complexes of HT-29 cells and that positive fluorescent microscopy and blebbing support previous studies of cell death via apoptosis.

Endocrine-disrupting activity of mancozeb

The objective of the present study was to review the existing data on the mechanisms involved in the endocrine disrupting activity of mancozeb (MCZ) in its main targets, including thyroid and gonads, as well as other endocrine tissues that may be potentially affected by MCZ. MCZ exposure was shown to interfere with thyroid functioning through impairment of thyroid hormone synthesis due to inhibition of sodium-iodine symporter (NIS) and thyroid peroxidase (TPO) activity, as well as thyroglobulin expression. Direct thyrotoxic effect may also contribute to thyroid pathology upon MCZ exposure. Gonadal effects of MCZ involve inhibition of sex steroid synthesis due to inhibition of P450scc (CYP11A1), as well as 3β-HSD and 17β-HSD. In parallel with altered hormone synthesis, MCZ was shown to down-regulate androgen and estrogen receptor signaling. Taken together, these gonad-specific effects result in development of both male and female reproductive dysfunction. In parallel with clearly estimated targets for MCZ endocrine disturbing activity, namely thyroid and gonads, other endocrine tissues may be also involved. Specifically, the fungicide was shown to affect cortisol synthesis that may be mediated by modulation of CYP11B1 activity. Moreover, MCZ exposure was shown to interfere with PPARγ signaling, being a key regulator of adipogenesis. The existing data also propose that endocrine-disrupting effects of MCZ exposure may be mediated by modulation of hypothalamus-pituitary-target axis. It is proposed that MCZ neurotoxicity may at least partially affect central mechanisms of endocrine system functioning. However, further studies are required to unravel the mechanisms of MCZ endocrine disrupting activity and overall toxicity.

Antimycotic Activity of Ozonized Oil in Liposome Eye Drops against Candida spp

Purpose

This study aims to investigate the antifungal activity and mechanism of action of ozonized oil eye drops in liposomes (Ozodrop), commercialized as eye lubricant for the treatment of dry eye syndrome and eye inflammation. The activity was tested against four clinical Candida species: C albicans, C glabrata, C krusei, and C orthopsilosis.

Methods

The antifungal activity of the eye drop solution was ascertained by microdilution method in accordance with EUCAST obtaining the minimum inhibitory concentration for Ozodrop. The mechanism of action was further investigated in C albicans by measuring cell vitality, intracellular reactive oxygen species production, levels of cellular and mitochondrial (∆Ψ_m) membrane potential, and the extent of membrane lipid peroxidation.

Results

All Candida isolates were susceptible to Ozodrop with minimum inhibitory concentration values ranging from 0.195% (v/v) for C glabrata to 6.25% (v/v) for C orthopsilosis. After 1 hour of exposure at the minimum inhibitory concentration value about 30% of cells were killed, reaching about 70% at the highest Ozodrop value. After Ozodrop exposure, C albicans showed cell membrane depolarization, increased levels of lipid peroxidation, depolarized ∆Ψ_m, and increased reactive oxygen species generation.

Conclusions

The significant increases in reactive oxygen species production cause the accumulation of reactive oxygen species-associated damages leading to progressive Candida cell dysfunction.

Translational Relevance

The antifungal activity of Ozodrop was demonstrated at concentrations several times lower than the concentration that can be retrieved in ocular surface after its application. The antifungal activity of the eye drops Ozodrop would represent an interesting off-label indication for a product basically conceived as an eye lubricant.

Tebuconazole and Econazole Act Synergistically in Mediating Mitochondrial Stress, Energy Imbalance, and Sequential Activation of Autophagy and Apoptosis in Mouse Sertoli TM4 Cells: Possible Role of AMPK/ULK1 Axis

Tebuconazole and Econazole are triazole and imidazole fungicides currently used worldwide. Although their reproductive toxicity in mammals has been described, their effect on male reproductive systems has been poorly investigated. As humans may be exposed to different azole compounds simultaneously, the combinational in vitro toxicity of Tebuconazole and Econazole (MIX) in mouse Sertoli TM4 cells was investigated. This study demonstrates that Tebuconazole (40 µM) and Econazole (20 µM) act synergistically in mediating decrease of mitochondrial membrane potential (ΔΨm) and changes in mitochondrial morphology. These events were associated with ATP depletion, cell cycle arrest, and sequential activation of autophagy and apoptosis. Remarkable differences on other parameters such as AMP/ATP ratio and adenylate energy charge were observed. Pharmacological inhibition of autophagy by bafilomycin A1 leads to enhanced MIX-induced apoptosis suggesting an adaptive cytoprotective function for MIX-modulated autophagy. Finally, a possible role of AMPK/ULK1 axis in mediating adaptive signalling cascades in response to energy stress was hypothesized. Consistently, ULK1 Ser 555 phosphorylation occurred in response to AMPK (Thr 172) activation. In conclusion, Tebuconazole and Econazole combination, at concentrations relevant for dermal and clinical exposure, induces a severe mitochondrial stress in SCs. Consequently, a prolonged exposure may affect the ability of the cells to re-establish homeostasis and trigger apoptosis.

Association between Female Reproductive Health and Mancozeb: Systematic Review of Experimental Models

Mancozeb is a widely used fungicide approved for use in agriculture in many countries with long persistence in the environment and consequent bioaccumulation in tissues and biological fluids. Despite the large amount of studies published in recent years, the relationship between mancozeb exposure and female reproductive health is not fully elucidated. In order to summarize current evidence on mancozeb exposure and female reproductive disease, we performed a systematic review of literature. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to make this review. An adapted version of the National Toxicology Program’s Office of Health and Assessment and Translation (OHAT) framework was used to evaluate the risk of bias. Electronic search on two databases (PubMed and Scopus) was used to find experimental studies (in vitro and in vivo) on mancozeb exposure. The database search identified 250 scientific articles, 20 of which met our inclusion criteria. Selected data were then reviewed and summarized in tables. Overall, mancozeb represents a hazard for female reproductive health, with different mechanisms of action. Undoubtedly more experimental and epidemiological studies are required to definitively validate mancozeb as reproductive toxicant.

Electrochemical Characterization of Mancozeb Degradation for Wastewater Treatment Using a Sensor Based on Poly (3,4-ethylenedioxythiophene) (PEDOT) Modified with Carbon Nanotubes and Gold Nanoparticles

Mancozeb is a worldwide fungicide used on a large scale in agriculture. The active component and its main metabolite, ethylene thiourea, has been related to health issues. Robust, fast, and reliable methodologies to quantify its presence in water are of great importance for environmental and health reasons. The electrochemical evaluation of mancozeb using a low-cost electrochemical electrode modified with poly (3,4-ethylene dioxythiophene), multi-walled carbon nanotubes, and gold nanoparticles is a novel strategy to provide an in-situ response for water pollution from agriculture. Additionally, the thermal-, electrochemical-, and photo-degradation of mancozeb and the production of ethylene thiourea under controlled conditions were evaluated in this research. The mancozeb solutions were characterized by electrochemical oxidation and ultraviolet-visible spectrophotometry, and the ethylene thiourea concentration was measured using ultra-high-performance liquid chromatography high-resolution mass spectrometry. The degradation study of mancozeb may provide routes for treatment in wastewater treatment plants. Therefore, a low-cost electrochemical electrode was fabricated to detect mancozeb in water with a robust electrochemical response in the linear range as well as a quick response at a reduced volume. Hence, our novel modified electrode provides a potential technique to be used in environmental monitoring for pesticide detection.

Acute Maneb Exposure Significantly Alters Both Glycolysis and Mitochondrial Function in Neuroblastoma Cells

The pesticides paraquat (PQ) and maneb (MB) have been described as environmental risk factors for Parkinson's disease (PD), with mechanisms associated with mitochondrial dysfunction and reactive oxygen species generation. A combined exposure of PQ and MB in murine models and neuroblastoma cells has been utilized to further advance understanding of the PD phenotype. MB acts as a redox modulator through alkylation of protein thiols and has been previously characterized to inhibit complex III of the electron transport chain and uncouple the mitochondrial proton gradient. The purpose of this study was to analyze ATP-linked respiration and glycolysis in human neuroblastoma cells utilizing the Seahorse extracellular flux platform. Employing an acute, subtoxic exposure of MB, this investigation revealed a MB-mediated decrease in mitochondrial oxygen consumption at baseline and maximal respiration, with inhibition of ATP synthesis and coupling efficiency. Additionally, MB-treated cells showed an increase in nonmitochondrial respiration and proton leak. Further investigation into mitochondrial fuel flex revealed an elimination of fuel flexibility across all 3 major substrates, with a decrease in pyruvate capacity as well as glutamine dependency. Analyses of glycolytic function showed a substantial decrease in glycolytic acidification caused by lactic acid export. This inhibition of glycolytic parameters was also observed after titrating the MB dose as low as 6 μM, and appears to be dependent on the dithiocarbamate functional group, with manganese possibly potentiating the effect. Further studies into cellular ATP and NAD levels revealed a drastic decrease in cells treated with MB. In summary, MB significantly impacted both aerobic and anaerobic energy production; therefore, further characterization of MB's effect on cellular energetics may provide insight into the specificity of PD to dopaminergic neurons.

Neurotoxicity of pesticides

Pesticides are unique environmental contaminants that are specifically introduced into the environment to control pests, often by killing them. Although pesticide application serves many important purposes, including protection against crop loss and against vector-borne diseases, there are significant concerns over the potential toxic effects of pesticides to non-target organisms, including humans. In many cases, the molecular target of a pesticide is shared by non-target species, leading to the potential for untoward effects. Here, we review the history of pesticide usage and the neurotoxicity of selected classes of pesticides, including insecticides, herbicides, and fungicides, to humans and experimental animals. Specific emphasis is given to linkages between exposure to pesticides and risk of neurological disease and dysfunction in humans coupled with mechanistic findings in humans and animal models. Finally, we discuss emerging techniques and strategies to improve translation from animal models to humans.

Agricultural exposures to carbamate herbicides and fungicides and central nervous system tumour incidence in the cohort AGRICAN

BACKGROUND

Pesticides exposures could be implicated in the excess of Central Nervous System (CNS) tumors observed in farmers, but evidence concerning individual pesticides remains limited. Carbamate derivative pesticides, including herbicides and fungicides (i.e. (thio/dithio)-carbamates), have shown evidence of carcinogenicity in experimental studies in animals. In the French AGRICAN cohort, we assessed the associations between potential exposures to carbamate herbicides and fungicides and the incidence of CNS tumors, overall and by histological subtype.

METHODS

AGRICAN enrolled 181,842 participants involved in agriculture. Incident CNS tumors were identified by linkage with cancer registries from enrollment (2005-2007) until 2013. Individual exposures were assessed by combining information on lifetime periods of pesticide use on crops and the French crop-exposure matrix PESTIMAT, for each of the 14 carbamate and thiocarbamate herbicides and the 16 carbamate and dithiocarbamate fungicides registered in France since 1950. Associations were estimated using proportional hazard models with age as the underlying timescale, adjusting for gender, educational level and smoking.

RESULTS

During an average follow-up of 6.9 years, 381 incident cases of CNS tumors occurred, including 164 gliomas and 134 meningiomas. Analyses showed increased risks of CNS tumors with overall exposure to carbamate fungicides (Hazard Ratio, HR = 1.88; 95% CI: 1.27-2.79) and, to a lesser extent, to carbamate herbicides (HR = 1.44; 95% CI: 0.94-2.22). Positive associations were observed with specific carbamates, including some fungicides (mancozeb, maneb, metiram) and herbicides (chlorpropham, propham, diallate) already suspected of being carcinogens in humans.

CONCLUSIONS

Although some associations need to be corroborate in further studies and should be interpreted cautiously, these findings provide additional carcinogenicity evidence for several carbamate fungicides and herbicides.

Developmental exposure to mancozeb induced neurochemical and morphological alterations in adult male mouse hypothalamus

Mancozeb, a dithiocarbamate widely used in agriculture, is considered a developmental hazard in humans; however, more evidences are still needed concerning the consequences of chronic exposure to this pesticide. Mancozeb neurotoxicity in developing mouse hypothalamus was evaluated by subchronic exposure of male Mus musculus mice to low and high doses of mancozeb (30 and 90 mg/kg body weight, respectively) from late neonatal until adolescence. Variations in hypothalamic amino acid neurotransmitter levels and changes in histological as well as cytological characteristics were analyzed in young adult experimental mice and compared with control. A dose-dependent increase in excitation/ inhibition ratio was observed in mancozeb-exposed hypothalamus, indicating an overall state of excitoxicity. Histopathological and ultrastructural studies showed increased apoptosis, neuroinflammation and demyelination, demonstrating mancozeb-induced cytotoxicity in hypothalamic neurosecretory cells. In summary, both neurochemical and morphological data revealed mancozeb-induced alterations during development of hypothalamic circuitry that are critical for maturation of the neuroendocrine system.

VEGFR2 Expression Is Differently Modulated by Parity and Nulliparity in Mouse Ovary

Parity and nulliparity exert opposite effects on women's health, as parity is considered a protective factor for several reproductive diseases. This study is aimed at determining if ovarian VEGF and VEGFR2 expression are differently modulated in the ovaries of parous and nulliparous mice. To this end primiparous and nulliparous fertile mice were sacrificed at postovulatory stage. Whole ovaries, corpus luteum, and residual stromal tissues were analyzed to assess VEGF/VEGFR2 expression levels. Ovarian mRNA amounts of Vegfa (120 and 164) and Vegfr2 were comparable between primiparous and nulliparous mice; both isoforms and receptor were accumulated mainly in corpus luteum tissues. VEGF 120 and 164 protein accumulation and distribution mirrored that of mRNA. Conversely, VEGFR2 protein content was significantly higher in ovaries of nulliparous mice and was more efficiently phosphorylated in ovaries of primiparous mice. In both groups, VEGFR2 was preferentially expressed in corpus luteum, while its phosphorylated form was equally distributed in two somatic compartments. We suggest that parity influences VEGFR2/phospho-VEGFR2 expression and tissue distribution. This difference could be part of a more complex mechanism that at least in mice is activated after the first pregnancy and likely aims to preserve female health.

Evaluating biological activity of compounds by transcription factor activity profiling

Assessing the biological activity of compounds is an essential objective of biomedical research. We show that one can infer the bioactivity of compounds by assessing the activity of transcription factors (TFs) that regulate gene expression. Using a multiplex reporter system, the FACTORIAL, we characterized cell response to a compound by a quantitative signature, the TF activity profile (TFAP). We found that perturbagens of biological pathways elicited distinct TFAP signatures in human cells. Unexpectedly, perturbagens of the same pathway all produced identical TFAPs, regardless of where or how they interfered. We found invariant TFAPs for mitochondrial, histone deacetylase, and ubiquitin/proteasome pathway inhibitors; cytoskeleton disruptors; and DNA-damaging agents. Using these invariant signatures permitted straightforward identification of compounds with specified bioactivities among uncharacterized chemicals. Furthermore, this approach allowed us to assess the multiple bioactivities of polypharmacological drugs. Thus, TF activity profiling affords straightforward assessment of the bioactivity of compounds through the identification of perturbed biological pathways.

Mancozeb induces testicular dysfunction through oxidative stress and apoptosis: Protective role of N-acetylcysteine antioxidant

Mancozeb (MZB) is one of the fungicides used in pest control programs that might affect human health including reproductive system. The aim of this study was to demonstrate the mechanisms through which MZB induces testicular tissue damage and the probable protective effect of N-acetylcysteine (NAC), a modified amino acid, with antioxidant property, against MZB toxicity in an animal model. Male albino mice ( n = 8) were exposed to different doses of MZB (250 and 500 mg/kg/day) by oral gavage without or with NAC (200 mg/kg, twice/week) for 40 days. Sub-chronic MZB dose-dependently decreased sperm motility and count. Exposure to MZB increased lipid peroxidation and protein carbonyl, while it reduced antioxidant enzymes activities, total antioxidant capacity, and glutathione content. The histopathological examination clearly showed deleterious changes in the testicular structure. At the molecular levels, the results of quantitative real time-poly chain reaction (qRT-PCR) showed that MZB upregulated oxidative stress markers inducible nitric oxide synthase (iNOS) and NADPH oxidase 4 (NOX4) and downregulated expression of the glutathione peroxidase 1 (Gpx1) gene as one of the most important antioxidant enzymes. MZB also induced apoptosis dose-dependently in the testes as determined by the terminal dUTP nick-end labeling assay and immunoblotting. NAC administration decreased the mRNA levels of both iNOS and NOX4 with a concomitant increase in Gpx1 expression. It also significantly decreased MZB-induced oxidative stress and apoptosis. Collectively, the present study showed MZB-induced oxidative damage in testes leading to apoptosis. It revealed that antioxidants such as NAC can mitigate oxidant injury induced by the dithiocarbamate pesticides in the reproductive system.

Slow and temperature-mediated pathogen adaptation to a nonspecific fungicide in agricultural ecosystem

The spread of antimicrobial resistance and global change in air temperature represent two major phenomena that are exerting a disastrous impact on natural and social issues but investigation of the interaction between these phenomena in an evolutionary context is limited. In this study, a statistical genetic approach was used to investigate the evolution of antimicrobial resistance in agricultural ecosystem and its association with local air temperature, precipitation, and UV radiation. We found no resistance to mancozeb, a nonspecific fungicide widely used in agriculture for more than half a century, in 215 Alternaria alternata isolates sampled from geographic locations along a climatic gradient and cropping system representing diverse ecotypes in China, consistent with low resistance risk in many nonspecific fungicides. Genetic variance accounts for ~35% of phenotypic variation, while genotype-environment interaction is negligible, suggesting that heritability plays a more important role in the evolution of resistance to mancozeb in plant pathogens than phenotypic plasticity. We also found that tolerance to mancozeb in agricultural ecosystem is under constraining selection and significantly associated with local air temperature, possibly resulting from a pleiotropic effect of resistance with thermal and other ecological adaptations. The implication of these results for fungicide and other antimicrobial management in the context of global warming is discussed.

Mancozeb impairs the ultrastructure of mouse granulosa cells in a dose-dependent manner

Mancozeb, an ethylene bis-dithiocarbamate, is widely used as a fungicide and exerts reproductive toxicity in vivo and in vitro in mouse oocytes by altering spindle morphology and impairing the ability to fertilize. Mancozeb also induces a premalignant status in mouse granulosa cells (GCs) cultured in vitro, as indicated by decreased p53 expression and tenuous oxidative stress. However, the presence and extent of ultrastructural alterations induced by mancozeb on GCs in vitro have not yet been reported. Using an in vitro model of reproductive toxicity, comprising parietal GCs from mouse antral follicles cultured with increasing concentrations of mancozeb (0.001–1 µg/ml), we sought to ascertain the in vitro ultrastructural cell toxicity by means of transmission (TEM) and scanning (SEM) electron microscopy. The results showed a dose-dependent toxicity of mancozeb on mouse GCs. Ultrastructural data showed intercellular contact alterations, nuclear membrane irregularities, and chromatin marginalization at lower concentrations, and showed chromatin condensation, membrane blebbing, and cytoplasmic vacuolization at higher concentrations. Morphometric analysis evidenced a reduction of mitochondrial length in GCs exposed to mancozeb 0.01−1 µg/ml and a dose-dependent increase of vacuole dimension. In conclusion, mancozeb induced dose-dependent toxicity against GCs in vitro, including ultrastructural signs of cell degeneration compatible with apoptosis, likely due to the toxic breakdown product ethylenethiourea. These alterations may represent a major cause of reduced/delayed/missed oocyte maturation in cases of infertility associated with exposure to pesticides.

Protective effects of Oviductus Ranae-containing serum on oxidative stress-induced apoptosis in rat ovarian granulosa cells

ETHNOPHARMACOLOGICAL RELEVANCE

Oviductus Ranae (OR) is a traditional Chinese medicine derived from Rana temporaria chensinensis David, and is known to have a wide variety of pharmacological effects.

AIM OF THE STUDY

To investigate the function and mechanism of OR-containing serum in protecting rat ovarian granulosa cells from hydrogen peroxide (H₂O₂)-induced oxidative damage.

MATERIALS AND METHODS

H₂O₂-treated granulosa cells were pretreated with OR-containing serum, and viability and proliferation assays were carried out using Cell Counting Kit-8 (CCK-8). Apoptotic granulosa cells were observed microscopically using 4',6-diamidino-2-phenylindole (DAPI), and the apoptotic ratio was quantified via Annexin V/ propidium iodide (PI) staining combined with flow cytometry. The levels of reactive oxygen species (ROS) and mitochondrial membrane potential (ΔΨm) in the cells were measured using 2,7-dichlorofluorescein diacetate (DCFH-DA) and rhodamine 123, respectively, and analyzed by flow cytometry. Mitogen-activated protein kinases (MAPKs), including ERK1/2, JNK, and p38, and other apoptosis-related proteins (p53, Bcl-2, Bax, caspase-9, caspase-3), were detected by western blot analysis, and the related mRNA levels were detected using reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

The results revealed that treatment with OR-containing serum reduced apoptosis and mitochondrial membrane damage in H₂O₂-treated granulosa cells. The OR-containing serum interfered with H₂O₂-induced intracellular generation of ROS and loss of ΔΨm, which typically lead to apoptosis. Furthermore, the OR-containing serum down-regulated pro-apoptotic proteins such as p53, Bax, caspase-9, and caspase-3, while up-regulating the anti-apoptotic protein Bcl-2. Finally, the OR-containing serum increased phosphorylation of ERK1/2, and reduced JNK and p38 phosphorylation.

CONCLUSIONS

OR-containing serum protected rat ovarian granulosa cells against H₂O₂-induced apoptosis, by reducing ROS production and improving mitochondrial membrane potential, through down-regulation of negative regulators of proliferation, activation of ERK1/2, and inhibition of the activity of JNK and p38.

Apoptotic effects of bovine apo-lactoferrin on HeLa tumor cells

Lactoferrin (Lf), a cationic iron-binding glycoprotein of 80 kDa present in body secretions, is known as a compound with marked antimicrobial activity. In the present study, the apoptotic effect of iron-free bovine lactoferrin (apo-bLf) on human epithelial cancer (HeLa) cells was examined in association with reactive oxygen species and glutathione (GSH) levels. Apoptotic effect of iron-free bovine lactoferrin inhibited the growth of HeLa cells after 48 hours of treatment while the diferric-bLf was ineffective in the concentration range tested (from 1 to 12.5 μM). Western blot analysis showed that key apoptotic regulators including Bax, Bcl-2, Sirt1, Mcl-1, and PARP-1 were modulated by 1.25 μM of apo-bLf. In the same cell line, apo-bLf induced apoptosis together with poly (ADP-ribose) polymerase cleavage, caspase activation, and a significant drop of NAD⁺ . In addition, apo-bLf-treated HeLa cells showed a marked increase of reactive oxygen species level and a significant GSH depletion. On the whole, apo-bLf triggered apoptosis of HeLa cells upon oxygen radicals burst and GSH decrease.

Mitochondrial DNA in Telocytes

Telocyte (TC) is a new identified interstitial cell type with a small nuclear and one or several long and thin prolongations with enlargements on them. They were found in many mammals including humans, mouse, rats, dogs, and monkeys and play vital roles in many physiological and pathological conditions. The ultrastructure of mitochondria was observed in TCs, and the alterations were found in TCs from inflammatory ureter tissue. MtDNA is associated with mitochondria normal functions and involved in physiological and pathological processes. However, mitochondria and mtDNA in TCs were not investigated deeply. This review will introduce the origin, distribution, morphology, and functions of TCs and the distribution and functions of TC mitochondria in order to improve a better understanding of the potential functions of mtDNA in TCs.

Acute exposure to a Mn/Zn ethylene-bis-dithiocarbamate fungicide leads to mitochondrial dysfunction and increased reactive oxygen species production in Caenorhabditis elegans

Mn/Zn ethylene-bis-dithiocarbamate (Mn/Zn-EBDC) fungicides are among some the most widely-used fungicides in the world. Although they have been available for over 50 years, little is known about their mechanism of action in fungi, or their potentially toxic mechanisms in humans. To determine if exposure of Caenorhabditis elegans (C. elegans) to a representative fungicide (Manzate; MZ) from this group inhibits mitochondria or produces reactive oxygen species (ROS), we acutely (30min) exposed worms to various MZ concentrations. Initial oxygen consumption studies showed an overall statistically significant decrease in oxygen consumption associated with addition of Complex I- and/or II-substrate in treatment groups compared to controls (*p<0.05). In order to better characterize the individual complex activity, further studies were completed that specifically assessed Complex II or Complex IV. Data indicated that neither of these two complexes were targets of MZ treatment. Results from tetramethylrhodamine ethyl ester (proton gradient) and ATP assays showed statistically significant reductions in both endpoints (*p<0.05, **p<0.01, respectively). Additional studies were completed to determine if MZ treatment also resulted in increased ROS production. These assays provided evidence that hydrogen peroxide, but not superoxide or hydroxyl radical levels were statistically significantly increased (*p<0.05). Taken together, these data indicate exposure of C. elegans to MZ concentrations to which humans are exposed leads to mitochondrial inhibition and concomitant hydrogen peroxide production. Since mitochondrial inhibition and increased ROS are associated with numerous neurodegenerative diseases, we suggest further studies to determine if MZ catalyzes similar toxic processes in mammals.

Caenorhabditis elegans chronically exposed to a Mn/Zn ethylene-bis-dithiocarbamate fungicide show mitochondrial Complex I inhibition and increased reactive oxygen species

Reports have linked human exposure to Mn/Zn ethylene-bis-dithiocarbamate (Mn/Zn-EBDC) fungicides with multiple pathologies, from dermatitis to central nervous system dysfunction. Although members of this family of agrochemicals have been available for over 50 years, their mechanism of toxicity in humans is still unclear. Since mitochondrial inhibition and oxidative stress are implicated in a wide variety of diseases, we hypothesized that Caenorhabditis elegans (C. elegans) exposed to a commercially-available formulation of an Mn/Zn-EBDC-containing fungicide (Manzate; MZ) would also show these endpoints. Thus, worms were treated chronically (24h) with various MZ concentrations and assayed for reduced mitochondrial function and increased levels of reactive oxygen species (ROS). Oxygen consumption studies suggested Complex I inhibition in all treatment groups compared to controls (^**p<0.01). In order to verify these findings, assays specific for Complex II or Complex IV activity were also completed. Data analysis from these studies indicated that neither complex was adversely affected by MZ treatment. Additional data from ATP assays indicated a statistically significant decrease (^***p<0.001) in ATP levels in all treatment groups when compared to control worms. Further studies were completed to determine if exposure of C. elegans to MZ also resulted in increased ROS concentrations. Studies demonstrated that hydrogen peroxide, but not superoxide or hydroxyl radical, levels were statistically significantly increased (*p<0.05). Since hydrogen peroxide is known to up-regulate glutathione-S-transferase (GST), we used a GST:green fluorescent protein transgenic worm strain to test this hypothesis. Results from these studies indicated a statistically significant increase (^***p<0.001) in green pixel number following MZ exposure. Taken together, these data indicate that C. elegans treated with MZ concentrations to which humans are exposed show mitochondrial Complex I inhibition with concomitant hydrogen peroxide production. Since these mechanisms are associated with numerous human diseases, we suggest further studies to determine if MZ exposure induces similar toxic mechanisms in mammals.