The protective function of taurine on pesticide-induced permanent neurodevelopmental toxicity in juvenile rats.

Numerous studies have confirmed that prenatal or early postnatal exposure to pesticides can lead to functional deficits in the developing brain. This study aimed to investigate whether combined exposure to paraquat (PQ) and maneb (MB) during puberty could cause permanent toxic effects in the neural system of rats. In addition, the neuroprotective function of taurine (T) and its possible mechanism were investigated. Rats were administered PQ + MB intragastrically for 12 continuous weeks, while taurine dissolved in water was fed to the rats for 24 continuous weeks. In the behavioral tests, the rats' trajectories became complex, and the reaction latencies and mistake frequencies increased. Significant changes were found in the hippocampal neurons of the PQ + MB groups but not in the taurine treatment groups. PQ + MB stimulated cAMP to reduce the production of protein kinase A (PKA) and inhibited the activation of other elements, such as brain-derived neurotrophic factor (BDNF), cAMP response element binding protein (CREB), phospho-CREB (p-CREB), immediate-early genes (IEGs)Arc, and c-Fos. Importantly, taurine regulated the level of cAMP and the expression of the abovementioned proteins. Together, our findings implied that adolescent exposure to PQ + MB may impact the behavior and cognitive function of rats via the cAMP-PKA-CREB signaling pathway, while taurine may in turn exert neuroprotection by diminishing these impacts.

Determining Mancozeb Deposition Benchmark Values on Apple Leaves for the Management of Venturia inaequalis.

Apple scab, caused by Venturia inaequalis, is the most common fruit and foliar disease in commercial apple production worldwide. Early in the production season, preventative contact fungicide sprays are essential for protecting highly susceptible continuously unfolding and expanding young leaves. In South Africa, mancozeb is a key contact fungicide used for controlling apple scab early in the season. The current study developed deposition benchmarks indicative of the biological efficacy of mancozeb against apple scab, using a laboratory-based apple seedling model system. The model system employed a yellow fluorescent pigment that is known to be an effective tracer of mancozeb deposition. A concentration range of mancozeb (0.15 to 1 times the registered dosage) and fluorescent pigment concentrations was sprayed onto seedling leaves, which yielded various fluorescent particle coverage (FPC%) levels. Modeling of the FPC% values versus percent disease control yielded different benchmark values when disease quantification was conducted using two different methods. Thermal infrared imaging (TIRI) disease quantification resulted in a benchmark model where 0.40%, 0.79%, and 1.35 FPC% yielded 50, 75, and 90% apple scab control, respectively. These FPC% values were higher than the benchmarks (0.10, 0.20, and 0.34 FPC%, respectively) obtained with quantitative real-time PCR (qPCR) disease quantification. The qPCR benchmark model is recommended as a guideline for evaluating the efficacy of mancozeb sprays on leaves in apple orchards since the TIRI benchmark model underestimated disease control. The TIRI benchmark model yielded 68% disease control at the lowest mancozeb dosage, yet no visible lesion developed at this dosage. Both benchmark models showed that mancozeb yielded high levels of disease control at very low concentrations; for the qPCR benchmark model the FPC% value of the FPC90 (90% control) corresponded to 0.15 times that of the registered mancozeb concentration in South Africa, i.e., 85% lower than the registered dosage.

Amphiphilic polymer based nanoformulations of mancozeb for management of early blight in tomato.

Controlled release (CR) nanoformulations of Mancozeb (Manganese-zinc double salt of N, N-bisdithiocarbamic acid), a protective fungicide, have been developed using poly (ethylene glycols) (PEGs) based functionalized amphiphilic copolymers and evaluated for the management of early blight in tomato. During the field experiment, it was observed that number of infected leaflets/plants were less in developed formulation treated plants as compared to commercial products. Number of infected leaflets per plant was 2.40-4.60 and the number of fruits per plant were 6.40-9.00 at 50 mg L-1, whereas at 100 mg L-1, the corresponding numbers were 2.10-4.10 and 6.30-9.10 respectively. These formulations can be used to optimize the release of Mancozeb to achieve disease control for the desired period depending upon the matrix of the polymer used. Importantly, sufficient amount of active ingredient remains available for a reasonable period of time after application leading to reduced number of applications of pesticide.

Cross-resistance of the pathogenic fungus Alternaria alternata to fungicides with different modes of action.

BACKGROUND: Cross-resistance, a phenomenon that a pathogen resists to one antimicrobial compound also resists to one or several other compounds, is one of major threats to human health and sustainable food production. It usually occurs among antimicrobial compounds sharing the mode of action. In this study, we determined the sensitivity profiles of Alternaria alternata, a fungal pathogen which can cause diseases in many crops to two fungicides (mancozeb and difenoconazole) with different mode of action using a large number of isolates (234) collected from seven potato fields across China. RESULTS: We found that pathogens could also develop cross resistance to fungicides with different modes of action as indicated by a strong positive correlation between mancozeb and difenoconazole tolerances to A. alternata. We also found a positive association between mancozeb tolerance and aggressiveness of A. alternata, suggesting no fitness penalty of developing mancozeb resistance in the pathogen and hypothesize that mechanisms such as antimicrobial compound efflux and detoxification that limit intercellular accumulation of natural/synthetic chemicals in pathogens might account for the cross-resistance and the positive association between pathogen aggressiveness and mancozeb tolerance. CONCLUSIONS: The detection of cross-resistance among different classes of fungicides suggests that the mode of action alone may not be an adequate sole criterion to determine what components to use in the mixture and/or rotation of fungicides in agricultural and medical sects. Similarly, the observation of a positive association between the pathogen's aggressiveness and tolerance to mancozeb suggests that intensive application of site non-specific fungicides might simultaneously lead to reduced fungicide resistance and enhanced ability to cause diseases in pathogen populations, thereby posing a greater threat to agricultural production and human health. In this case, the use of evolutionary principles in closely monitoring populations and the use of appropriate fungicide applications are important for effective use of the fungicides and durable infectious disease management.

Thioredoxin and Glutaredoxin Systems Required for Oxidative Stress Resistance, Fungicide Sensitivity, and Virulence of Alternaria alternata.

This study determined the function of thioredoxin and glutaredoxin systems in the phytopathogenic fungus Alternaria alternata via analyzing mutants obtained from the targeted deletion of genes encoding thioredoxin peroxidase (Tsa1), thioredoxin reductase (Trr1), and glutathione reductase (Glr1). Trr1 and Glr1, but not Tsa1, are required for growth and conidiation. The reduced growth and conidiation seen in the Trr1 or Glr1 deletion mutant can be restored by glutathione. Deletion mutants showing growth inhibition by oxidants are defective for H2O2 detoxification and induce smaller lesions on citrus leaves. Trr1 and Glr1, but not Tsa1, also contribute to NaCl resistance. Glr1 is required for sorbitol resistance and is responsible for resistance to mancozeb and boscalid but not chlorothalonil fungicides, a novel phenotype that has not been reported in fungi. Trr1 is required for resistance to boscalid and chlorothalonil fungicides but confers susceptibility to mancozeb. The Tsa1 deletion mutant displays wild-type sensitivity to the tested fungicides. The expression of Tsa1 and Trr1 is regulated by the oxidative stress responsive regulators Yap1, Hog1, and Skn7. The expression of Tsa1, but not Trr1, is also regulated indirectly by the NADPH oxidase. The results indicate that the capability to resist oxidative stress is required for virulence of A. alternataIMPORTANCE The thioredoxin and glutaredoxin systems are important thiol antioxidant systems in cells, and knowledge of these two systems in the plant-pathogenic fungus A. alternata is useful for finding new strategies to reduce the virulence of this pathogen. In this study, we demonstrated that thiol antioxidant system-related genes (Tsa1, Trr1, and Glr1) are required for H2O2 detoxification and virulence in A. alternata Moreover, deletion of Trr1 results in hypersensitivity to the fungicides chlorothalonil and boscalid, and Glr1 deletion mutants are highly sensitive to mancozeb, which is the fungicide mostly used in citrus fields. Therefore, our findings demonstrate that the ability to detoxify reactive oxygen species (ROS) plays a critical role in pathogenesis on citrus and provide novel insights into the physiological functions of thiol-containing systems in fungicide sensitivity for A. alternata.

1,2,3-Triazole fused with pyridine/pyrimidine as new template for antimicrobial agents: Regioselective synthesis and identification of potent N-heteroarenes.

The 1,2,3-triazole ring fused with pyridine/pyrimidine was explored as new template for the identification of potential antimicrobial agents. The regioselective synthesis of these pre-designed N-heteroarenes was achieved via exploring the application of Buchwald's strategy (i.e. C-N bond formation/reduction/diazotization/cyclization sequence) to the N-heteroarene system. Two of them showed promising antibacterial (comparable to streptomycin) and several showed potent antifungal (comparable to mancozeb) activities.

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.

IFN-γ regulates xanthine oxidase-mediated iNOS-independent oxidative stress in maneb- and paraquat-treated rat polymorphonuclear leukocytes.

Maneb (MB) and paraquat (PQ) provoke oxidative stress-mediated cell damage. Role of xanthine oxidase (XO) in oxidative stress and its association with nitric oxide (NO)/NO synthase (NOS) have been widely reported. While inducible NOS (iNOS) is implicated in MB+PQ-induced toxicity in rat polymorphonuclear leukocytes (PMNs), role of XO and its alliance with iNOS have not yet been established. The study investigated the role of XO in MB+PQ-induced oxidative stress in rat PMNs and its regulation by iNOS and inflammatory cytokines. MB+PQ-augmented reactive oxygen species (ROS), superoxide, nitro-tyrosine, lipid peroxidation (LPO), and nitrite levels along with the catalytic activity of iNOS, superoxide dismutase (SOD), and XO. XO inhibitor, allopurinol (AP), alleviated MB+PQ-induced changes except nitrite content and iNOS activity. Conversely, an iNOS inhibitor, aminoguanidine, mitigated MB+PQ-induced LPO, nitrite, iNOS, and nitro-tyrosine levels; however, no change was observed in ROS, SOD, and XO. Nuclear factor-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), tumor necrosis factor-alpha (TNF-α) inhibitor, pentoxyfylline, and an anti-inflammatory agent, dexamethasone, attenuated MB+PQ-induced increase in XO, superoxide, and ROS with parallel reduction in the expression of interferon-gamma (IFN-γ), TNF-α, and interleukin-1ß (IL-1ß) in rat PMNs. Exogenous IFN-γ, TNF-α, and IL-1ß enhanced superoxide, ROS, and XO in the PMNs of control and MB+PQ-treated rats; however, IFN- γ was found to be the most potent inducer. Moreover, AP ameliorated cytokine-induced free radical generation and restored XO activity towards normalcy. The results thus demonstrate that XO mediates oxidative stress in MB+PQ-treated rat PMNs via iNOS-independent but cytokine (predominantly IFN-γ)-dependent mechanism.

The fungicide Mancozeb induces metacaspase-dependent apoptotic cell death in Saccharomyces cerevisiae BY4741.

Mancozeb (MZ), a mixture of ethylene-bis-dithiocarbamate manganese and zinc salts, is one of the most widely used fungicides in agriculture. Toxicologic studies in mammals and mammalian cells indicate that this fungicide can cause neurological and cytological disorders, putatively associated with pro-oxidant and apoptotic effects. Yeast adaptation to sub-inhibitory concentrations of MZ has been correlated with oxidative response, proteins degradation, and energy metabolism, and its main effect on yeast has been attributed to its high reactivity with thiol groups in proteins. Herein, we show that acute MZ treatments on aerobic exponentially growing yeast of wild type (BY4741) and deletion mutant strains, coupled with multiplex flow cytometry analysis, conclusively demonstrated that MZ displays the typical features of pro-oxidant activity on Saccharomyces, elevating mitochondrial ROS, and causing hyper-polarization of mitochondrial membranes leading to apoptosis. A drastic reduction of cellular viability associated with the maintenance of cell membrane integrity, as well as phosphatidyl serine externalization on yeast cells exposed to MZ, also supports an apoptotic mode of action. Moreover, abrogation of the apoptotic response in yca1 deficient mutants indicates that metacaspase-1 is involved in the programmed cell death mechanism induced by MZ in yeast.

Eco-friendly PEG-based controlled release nano-formulations of Mancozeb: Synthesis and bioefficacy evaluation against phytopathogenic fungi Alternaria solani and Sclerotium rolfsii.

Controlled release (CR) nano-formulations of Mancozeb (manganese-zinc double salt of N,N-bisdithiocarbamic acid), a protective fungicide, have been prepared using laboratory-synthesized poly(ethylene glycols) (PEGs)-based functionalized amphiphilic copolymers without using any surfactants or external additives. The release kinetics of the developed Mancozeb CR formulations were studied and compared with that of commercially available 42% suspension concentrate and 75% wettable powder. Maximum amount of Mancozeb was released on 42nd day for PEG-600 and octyl chain, PEG-1000 and octyl chain, and PEG-600 and hexadecyl chain, on 35th day for PEG-1000 and hexadecyl chain, on 28th day for PEG-1500 and octyl chain, PEG-2000 and octyl chain, PEG-1500 and hexadecyl chain, and PEG-2000 and hexadecyl chain in comparison to both commercial formulations (15th day). The diffusion exponent (n value) of Mancozeb in water ranged from 0.42 to 0.62 in tested formulations. The half-release (t1/2) values ranged from 17.35 to 35.14 days, and the period of optimum availability of Mancozeb ranged from 18.54 to 35.42 days. Further, the in vitro bioefficacy evaluation of developed formulations was done against plant pathogenic fungi Alternaria solani and Sclerotium rolfsii by poison food technique. Effective dose for 50% inhibition in mgL-1 (ED50) values of developed formulations varied from 1.31 to 2.79 mg L-1 for A. solani, and 1.60 to 3.14 mg L-1 for S. rolfsii. The present methodology is simple, economical, and eco-friendly for the development of environment-friendly CR formulations of Mancozeb. These formulations can be used to optimize the release of Mancozeb to achieve disease control for the desired period depending upon the matrix of the polymer used. Importantly, the maximum amount of active ingredient remains available for a reasonable period after application. In addition, the developed CR formulations were found to be suitable for fungicidal applications, allowing use of Mancozeb in lower doses.

Identification of metal dithiocarbamates as a novel class of antileishmanial agents.

Dithiocarbamates have emerged as potent carbonic anhydrase (CA) inhibitors in recent years. Given that CAs are important players in cellular metabolism, the objective of this work was to exploit the CA-inhibitory property of dithiocarbamates as a chemotherapeutic weapon against the Leishmania parasite. We report here strong antileishmanial activity of three hitherto unexplored metal dithiocarbamates, maneb, zineb, and propineb. They inhibited CA activity in Leishmania major promastigotes at submicromolar concentrations and resulted in a dose-dependent inhibition of parasite growth. Treatment with maneb, zineb, and propineb caused morphological deformities of the parasite and Leishmania cell death with 50% lethal dose (LD50) values of 0.56 µM, 0.61 µM, and 0.27 µM, respectively. These compounds were even more effective against parasites growing in acidic medium, in which their LD50 values were severalfold lower. Intracellular acidosis leading to apoptotic and necrotic death of L. major promastigotes was found to be the basis of their leishmanicidal activity. Maneb, zineb, and propineb also efficiently reduced the intracellular parasite burden, suggesting that amastigote forms of the parasite are also susceptible to these metal dithiocarbamates. Interestingly, mammalian cells were unaffected by these compounds even at concentrations which are severalfold higher than their antileishmanial LD50s). Our data thus establish maneb, zineb, and propineb as a new class of antileishmanial compounds having broad therapeutic indices.

Quercetin protected isolated human erythrocytes against mancozeb-induced oxidative stress.

Mancozeb is a fungicide belonging to the ethylene-bisdithiocarbamate group and is widely used in agriculture. The aim of this study was to examine the protective effect of quercetin (QRN) against oxidative stress induced by mancozeb in human erythrocytes. In order to verify this, 5 ml of venous blood was collected and the erythrocytes were separated and divided into equal parts. One part was incubated with different concentrations of mancozeb (0, 10, 30, 100 µM) for 4 h at 37°C. The other part was preincubated with QRN (40 and 80 µM) for 30 min, followed by mancozeb (0, 10, 30, 100 µM) incubation for 4 h. We found reduction in the levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) along with elevated levels of lipid peroxide (LPO) in erythrocytes incubated with 30 and 100 µm of mancozeb. Pre-incubation with QRN (80 µM) reversed oxidative stress induced by mancozeb (30 µM) and inhibited LPO induced at 100 µM by 64.36%. QRN also reduced the haemolytic effect on erythrocytes but could not prevent the induction of haemolysis by mancozeb. Therefore, these results suggest that QRN may play a role in preventing the oxidative stress induced by mancozeb in human erythrocytes.

Impact of fungicide mancozeb at different application rates on soil microbial populations, soil biological processes, and enzyme activities in soil.

The use of fungicides is the continuous exercise particularly in orchard crops where fungal diseases, such as white root rot, have the potential to destroy horticultural crops rendering them unsaleable. In view of above problem, the present study examines the effect of different concentrations of mancozeb (0-2000 ppm) at different incubation periods for their harmful side effects on various microbiological processes, soil microflora, and soil enzymes in alluvial soil (pH 6.8) collected from apple orchards of Shimla in Himachal Pradesh (India). Low concentrations of mancozeb were found to be deleterious towards fungal and actinomycetes population while higher concentrations (1000 and 2000 ppm) were found to be detrimental to soil bacteria. Mancozeb impaired the process of ammonification and nitrification. Similar results were observed for nitrifying and ammonifying bacteria. Phosphorus solubilization was increased by higher concentration of mancozeb, that is, 250 ppm and above. In unamended soil, microbial biomass carbon and carbon mineralization were adversely affected by mancozeb. Soil enzymes, that is, amylase, invertase, and phosphatase showed adverse and disruptive effect when mancozeb used was above 10 ppm in unamended soil. These results conclude that, to lessen the harmful effects in soil biological processes caused by this fungicide, addition of higher amount of nitrogen based fertilizers is required.

Lupeol acetate as a potent antifungal compound against opportunistic human and phytopathogenic mold Macrophomina phaseolina.

Antifungal activity of Monotheca buxifolia methanolic extract and its various fractions were assessed against Macrophomina phaseolina, a soil-borne fungal pathogen of more than 500 vegetal species as well as rare and emerging opportunistic human pathogen. Different concentrations of methanolic extract (3.125 to 200 mg mL-1) inhibited fungal biomass by 39-45%. Isolated n-hexane, chloroform and ethyl acetate fractions suppressed fungal biomass by 32-52%, 29-50% and 29-35%, respectively. Triterpenes lupeol and lupeol acetate (1, 2) were isolated from n-hexane while betulin, ß-sitosterol, ß-amyrin, oleanolic acid (3-6) were isolated from chloroform fraction. Vanillic acid, protocatechuic acid, kaempferol and quercetin (7-10) were isolated from the ethyl acetate fraction and identified using various spectroscopic techniques namely mass spectroscopy and NMR. Antifungal activity of different concentrations (0.0312 to 2 mg mL-1) of the isolated compounds was evaluated and compared with the activity of a broad spectrum fungicide mancozeb. Different concentrations of mencozeb reduced fungal biomass by 83-85%. Among the isolated compounds lupeol acetate (2) was found the highest antifungal against M. phaseolina followed by betulin (3), vanillic acid (7), protocatechuic acid (8), ß-amyrin (5) and oleanolic acid (6) resulting in 79-81%, 77-79%, 74-79%, 67-72%, 68-71% and 68-71%, respectively. Rest of the compounds also showed considerable antifungal activity and reduced M. phaseolina biomass by 41-64%.

Insights into yeast adaptive response to the agricultural fungicide mancozeb: a toxicoproteomics approach.

Toxicogenomics has the potential to elucidate gene-environment interactions to identify genes that are affected by a particular chemical at the early stages of the toxicological response and to establish parallelisms between different organisms. The fungicide mancozeb, widely used in agriculture, is an ethylene-bis-dithiocarbamate complex with manganese and zinc. Exposure to this pesticide has been linked to the development of idiopathic Parkinson's disease and cancer. Given that many signalling pathways and their molecular components are substantially conserved among eukaryotic organisms, we used Saccharomyces cerevisiae to get insights into the molecular mechanisms of mancozeb toxicity and adaptation based on expression proteomics. The early global response to mancozeb was analysed by quantitative proteomics using 2-DE. The target genes (e.g. TSA1, TSA2, SOD1, SOD2, AHP1, GRE2, GRX1, CYS3, PRE3, PRE6, PRE8, PRE9, EFT1, RPS5, TIF11, HSP31, HSP26, HSP104, HSP60, HSP70-family) and the putative main transcription activators (e.g. Yap1, Msn2/Msn4, Met4, Hsf1, Aft1, Pdr1, Skn7, Rpn4p, Gcn4) of the complex mancozeb-induced expression changes are related with yeast response to stress, in particular to oxidative stress, protein translation initiation and protein folding, disassembling of protein aggregates and degradation of damaged proteins. Our results also suggest that this study provided powerful indications that may be useful to expand the knowledge obtained in yeast not only to the global response to mancozeb toxicity in phytopathogenic fungi but also to humans.

Synthesis and antimicrobial activity of 1-benzhydryl-sulfonyl-4-(3-(piperidin-4-yl) propyl)piperidine derivatives against pathogens of Lycopersicon esculentum: a structure-activity evaluation study.

Several 1-benzhydryl-sulfonyl-4-(3-(piperidin-4-yl)propyl)piperidine derivatives 8(a-j) were prepared by the treatment of substituted benzhydryl chlorides with 4-(3-(piperidin-4-yl)propyl)piperidine followed by N-sulfonation with sulfonyl chlorides in the presence of dry methylene dichloride and triethyl amine. The synthesized compounds were characterized by (1)H-NMR, IR, and elemental analysis. All the synthesized compounds were evaluated in vitro for their efficacy as antimicrobial agents by artificial inoculation technique against standard strains of two important bacterial viz., Xanthomonas axonopodis pv. vesicatoria and Ralstonia solanacearum as well as and two fungal pathogens namely Alternaria solani and Fusarium solani of tomato plants. We have briefly investigated the structure-activity relation studies and reveal that the nature of substitutions on benzhydryl ring and sulfonamide ring influences the antibacterial activity. Among the synthesized new compounds 8b, 8d, 8g, 8h, 8i, and 8j were showed significant potent antimicrobial activities compared to the standard drugs chloramphenicol, mancozeb.

Utility of six fungicides for selective isolation of Evlachovaea sp. and Tolypocladium cylindrosporum.

The effects of the fungicides dodine, benomyl, thiabendazole, mancozeb, cupric sulfate, and copper oxychloride were examined in vitro upon germination and further development of Evlachovaea sp. and Tolypocladium cylindrosporum. Fungicidal activity depended on concentrations and varied among products, fungi and the strains tested. Depending on the fungicidal concentration, germination of conidia was induced but germlings produced neither mycelium nor new conidia. There was a good recovery of both Evlachovaea sp. and T. cylindrosporum from previously sterilized soils with fungicide-supplemented medium. Fungi were resistant to copper oxychloride up to 30 g/l, and this fungicide was found to have no utility for a selective medium. Minimal fungicide concentrations for successful isolations were 1 mg/l for benomyl, 200 mg/l for cupric sulfate, 50 mg/l for dodine, 100 mg/l for mancozeb, and 4 mg/l for thiabendazole. Thiabendazole, which is easy to obtain and can be used in low quantities, showed the greatest utility for a selective medium with these entomopathogenic fungi.

Development of a rapid methodology for biological efficacy assessment in banana plantations: application to reduced dosages of contact fungicide for Black Leaf Streak Disease (BLSD) control.

BACKGROUND: Black sigatoka is the main disease of banana crop production and is controlled by using either systemic or contact fungicides through spray applications. Biological efficacy is typically assessed on a whole cropping cycle with a natural infestation and periodic spray applications. Developing a faster methodology for assessment of the biological efficacy of a contact fungicide offers promising perspectives for testing current and new fungicides or application techniques. RESULTS: The methodology is based on the time of occurrence of the first BLSD symptoms. An artificial infestation protocol was optimized by multiplying the infestation spots and by covering the infested plants. Biological efficacy tests were based on a single spray application after infestation combining three mancozeb dose reductions and two nozzle types. Results demonstrated that a 50% reduction in the mancozeb rated dosage gave significant efficacy independently of the nozzle type, with a reduction of the number of lesions of up to 55% compared with control plants. CONCLUSIONS: The described method provides rapid and significant infestation. Further comparison of spray settings and fungicide doses was possible. This methodology will be tested at the plantation scale over a longer period covering the whole crop cycle. © 2018 Society of Chemical Industry.

Lesion of the Locus Coeruleus Damages Learning and Memory Performance in Paraquat and Maneb-induced Mouse Parkinson's Disease Model.

The damage of locus coeruleus (LC) noradrenergic neurons and associated with norepinephrine (NE) depletion are early events in Parkinson's disease (PD). Previous study showed that LC/NE neurodegeneration exacerbates dopaminergic neurotoxicity and motor deficits. However, whether the damage of LC/NE neurons contributes to non-motor symptoms in PD remain unclear. In this study, LC/NE neurons were pre-lesioned by N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4) in paraquat and maneb-induced mouse PD model. We found that DSP-4 significantly impaired learning and memory performance in paraquat and maneb-treated mice, although it failed to interfere with constipation and depression-like behaviors. Consistently, DSP-4 treatment increased hippocampal neurodegeneration, synaptic loss, α-synuclein expression and Ser129-phosphorylation in mice treated with these two pesticides. Mechanistically, DSP-4 increased iron content in hippocampus by disrupting the balance of iron release protein ferroportin 1 (Fpn-1) and transferrin receptor (TFR) in paraquat and maneb-treated mice. DSP-4 treatment also exacerbated paraquat and maneb-induced decrease of glutathione peroxidase 4 (GPX4) and glutathione contents as well as increase of lipid peroxidation and expressions of gp91phox and p47phox, two subunits of NADPH oxidase, which are all involved in ferroptosis, in mice. Furthermore, exaggerated microglial activation and M1 polarization were observed in DSP-4 and paraquat and maneb co-treated mice compared with paraquat and maneb alone group. Altogether, our findings revealed a critical role of LC/NE neurodegeneration in mediating learning and memory dysfunction in a two pesticide-induced mouse PD model through ferroptosis and microglia-mediated neuroinflammation, proving novel insights into the pathogenesis of cognitive dysfunction in PD.

Mancozeb selectively induces mitochondrial-mediated apoptosis in human gastric carcinoma cells through ROS generation.

Mancozeb (Manganese ethylene bis-dithiocarbamate with zinc salt) is a dithiocarbamate fungicide used to control fungal disease in many fruit plants, flowers and the maintenance of field crops. The effect of mancozeb on cell viability of human gastric adenocarcinoma AGS, SNU-1 cells and human normal FHs 74 Int cells were investigated. This study demonstrated that mancozeb was able to inhibit cell proliferation by 56-82% at 5-10 µM concentrations after 48 h. Mancozeb treatment for 48 h resulted in 33% (P < 0.05) and 61% (P < 0.001) increase in apoptotic cells at 5 and 10 µM concentrations in AGS cells, respectively. Treatment with mancozeb did not cause cell cycle arrest, while modulated the expression level of cleaved caspase-3, and cleavage of poly-(ADP-ribose) polymerase. Furthermore, treatment with mancozeb caused a rapid stimulation of reactive oxygen species (ROS) and loss of mitochondrial transmembrane potential. The results also showed that mancozeb-induced apoptosis was accompanied by up-regulation of Bax and down-regulation of Bcl-2 and Bcl-xL. Overall, our data suggested that mancozeb caused ROS generation which induced significant (P < 0.05) apoptosis in AGS cells that was attenuated with pretreatment of NAC. More importantly, same concentration of mancozeb did not show any considerable effect on cell growth, death, cell cycle arrest and ROS generation in normal FHs 74 Int cells. Overall, for the first time these results suggest that mancozeb has selective anticancer activity at lower concentrations against gastric cancer cells.