Mancozeb Treatment Research Articles

Evaluation of biocontrol efficacy of trichoderma harzianum against fusarium oxysporium in tomatoes ( <i>Solanum esculentum L.</i>)

Utilizing biological techniques to manage plant diseases has demonstrated efficacy in fostering ecosystem sustainability and augmenting agricultural output and quality. A study was undertaken at the Department of Plant Science and Biotechnology, Imo State University, Owerri, Nigeria to evaluate the suppressive impact of T. harzianum on the proliferation of F. oxysporusm f. sp. lycopersici, and the advancement of F. oxysporum infection in tomato plants. The trial comprised culturing only T. harzianum in the Petri dish, culturing T. harzianum and F. oxysporum in the Petri dish (dual culture), and culturing only F. oxysporum in the petri dish, and with Mancozeb. The influence of T. harzianum on the advancement of F. oxysporum infection in tomato plants comprises of four distinct concentrations (1g, 2g, 3g, and 4g) of T. harzianum extract. The results revealed that the dual culture of T. harzianum and F. oxysporum successfully suppressed the mycelial growth of F. oxysporum. On the seventh day, the level of antagonistic activity exhibited by T. harzianum against F. oxysporum peaked at 9.05mm. Leaf yellowing and severe wilting, indicative of Fusarium wilt, were seen during the monitoring period. Tomato disease incidence and severity exhibited a consistent linear decline with increasing concentrations of T. harzianum. The disease severity reached its maximum level, (31.6%) on week four. Mancozeb treatment compared favorably with 4g T. harzianum in decreasing the mycelial growth of F. oxysporium, and reducing wilt incidence and severity. Therefore, T. harzianum can function as a biocontrol agent, providing a sustainable substitute for synthetic fungicides in the control ofFusariumoxysporium wilt disease.

In Vitro Evaluation on Resistance of Phytopythium vexans (NG Isolate) Cultured from Sublethal Concentration against Several Fungicides

Phytopythium vexans isolated from potatoes rhizospher in Ngablak, Magelang, Central Java was reported having a potency to cause potato tuber rot in in vitro test. Some fungicides had been intensively applied in this area to control potato late blight even using sublethal dose. This study investigated resistance response of the pathogen against several fungicides which were Mancozeb, Dimethomorph, mixture of Mancozeb and Mefenoxam, and mixture of Oxathiapiprolin and Famoxadone. The experiment was conducted to observe the sensitivity response of pathogen against those fungicide and the experiment repeated with one of the isolates which growth in sublethal concentration to observe the resistance response. Both experiment data was analyzed by Probit Analysis. On sentivity test, data showed that P. vexans were insensitive against Dimethomorph, but it was sensitive against Mancozeb, mixture of Mancozeb and Mefenoxam, as well as mixture of Oxathiapiprolin and Famoxadone. On Mancozeb treatment, mycelia were inhibited 100% at the sugested concentration. However, at the sublethal concentration the mycelial collony grew abnormally. Pathogen isolate from the sublethal concentration were used as material for the resistance response study. The effect of the sublethal application of Mancozeb to P. vexans caused resistance to Mancozeb itself and cross resistance against Dimetomorph and mixture of Oxathiapiprolin and Famoxadone. It was proven by higher value of predicted EC50 and EC95 on the second experiment compared to the predicted EC50 and EC95 from the first one. The resistant P. vexans isolate was able to produce sporangium and chlamydospore.

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.

IN VITRO EFFICACY OF DISPARATE FUNGICIDES AGAINST Lasiodiplodia theobromae ROOT ROTS OF ORANGE-FLESHED SWEET-POTATO VARIETIES

Sweet-potato cultivation is limited globally by many storage rots caused mainly by fungi. The study aimed to test the effectiveness of several types of pesticides against <em>Lasioderma theobromae</em> <em>in vitro</em>. Three trials were set up using a completely randomized design with three replications. The first experiment used four isolates of <em>Trichoderma harzianum</em> (AIM16, NSBM, BGMZ4, and AIM3). The second trial was evaluating types of synthetic fungicides, i.e., mancozeb (50%, 100%), mancozeb+carbendazim (50%, 100%), and mancozeb+metalaxyl+Cu (50%, 100%). The third experiment testing botanical pesticides, namely leaf extracts of <em>Ixora, Guieria</em>, and <em>Bauhinia</em>, as well as <em>Eucalyptus</em> resin and <em>Ricinus </em>soap. The four isolates of <em>T. harzianum</em> inhibited the mycelia growth of <em>L. theobromae</em> by 8.0–100%, significantly different from the control, but there was no significant difference between the isolates. Solutions of mancozeb (100%) and mancozeb+carbendazim (50%, 100%) were more effective in suppressing the development of pathogenic mycelia compared to mancozeb+metalaxyl+Cu. Mancozeb treatment inhibited 8.0–100% of pathogen growth and was significantly different compared to other treatments. Plant extracts inhibited the growth of pathogens by 8.0–100%. <em>Ricinus</em> soap (50%, 100%), <em>Eucalyptus</em> (100%), and <em>Guieria</em> (100%) consistently inhibited the growth of pathogenic mycelia by 70%. Plant extracts and mancozeb were effective in suppressing the growth of pathogenic mycelia. The study indicates that <em>T. harziaum</em>, plant extracts, and mancozeb could be developed as a fungicide to control the soft rot fungus <em>L. theobromae</em> of sweet potato tubers

Effect of ozonated water, mancozeb, and thiophanate-methyl on the phyllosphere microbial diversity of strawberry.

Phyllosphere microorganisms are closely linked to plant health. This study investigated the effect of ozonated water, mancozeb, and thiophanate-methyl on phyllosphere microorganisms in strawberry plants of the “Hongyan” variety. Sequencing analysis of the phyllosphere bacterial and fungal communities was performed using 16S rRNA gene fragment and ITS1 region high-throughput sequencing after spraying ozonated water, mancozeb, thiophanate-methyl, and clear water. Proteobacteria, Actinobacteria, and Firmicutes were the dominant bacterial phyla in strawberry. The relative abundance of Proteobacteria (82.71%) was higher in the ozonated water treatment group than in the other treatment groups, while the relative abundance of Actinobacteria (9.38%) was lower than in the other treatment groups. The strawberry phyllosphere fungal communities were mainly found in the phyla Basidiomycota and Ascomycota. The relative abundance of Basidiomycota was highest in the ozonated water treatment group (81.13%), followed by the mancozeb treatment group (76.01%), while the CK group only had an abundance of 43.38%. The relative abundance of Ascomycota was lowest in the ozonated water treatment group (17.98%), 23.12% in the mancozeb treatment group, 43.39% in the thiophanate-methyl treatment group, and 55.47% in the CK group. Pseudomonas, Halomonas, and Nesterenkonia were the dominant bacterial genera on strawberry surfaces, while Moesziomyces, Aspergillus, and Dirkmeia were the dominant fungal genera. Ozonated water was able to significantly increase the richness of bacteria and fungi and decrease fungal diversity. However, bacterial diversity was not significantly altered. Ozonated water effectively reduced the relative abundance of harmful fungi, such as Aspergillus, and Penicillium, and enriched beneficial bacteria, such as Pseudomonas and Actinomycetospora, more effectively than mancozeb and thiophanate-methyl. The results of the study show that ozonated water has potential as a biocide and may be able to replace traditional agents in the future to reduce environmental pollution.

USE OF DIFFERENT FUNGICIDES IN WHEAT UNDER WATER DEFICIT CONDITIONS

The study aimed to evidence the efficiency of fungicides in disease control and the economic and productive effects under water deficit conditions in wheat. In addition, it sought to list the best management of fungicides so that the active principles can be more efficient in controlling diseases and, therefore, in the production of wheat grains. The experiment was carried out in São Borja – RS, in a randomized block design, with twenty treatments (fungicide management), in four replications, in 80 plots. The management composed by Versatilis + Versatilis potentiated the expression of cob length, number of grains per plant, leaf rust. Fusão + Fusão treatment promoted the lowest cob weight and grain weight per plant, similarly to Cypress + Mancozeb treatment. Orkestra + Fusão treatment enhanced grain yield and showed the best cost benefit, close to the value of the control treatment, proving to be the most profitable.

Cardiac developmental toxicity and transcriptome analyses of zebrafish (Danio rerio) embryos exposed to Mancozeb

Mancozeb (MZ), an antibacterial pesticide, has been linked to reproductive toxicity, neurotoxicity, and endocrine disruption. However, whether MZ has cardiactoxicity is unclear. In this study, the cardiotoxic effects of exposure to environment-related MZ concentrations ranging from 1.88 μM to 7.52 μM were evaluated at the larval stage of zebrafish. Transcriptome sequencing predicted the mechanism of MZ-induced cardiac developmental toxicity in zebrafish by enrichment analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO). Consistent with morphological changes, the osm, pfkfb3, foxh1, stc1, and nrarpb genes may effect normal development of zebrafish heart by activating NOTCH signaling pathways, resulting in pericardial edema, myocardial fibrosis, and congestion in the heart area. Moreover, differential gene expression analysis indicated that cyp-related genes (cyp1c2 and cyp3c3) were significantly upregulated after MZ treatment, which may be related to apoptosis of myocardial cells. These results were verified by real-time quantitative RT-qPCR and acridine orange staining. Our findings suggest that MZ-mediated cardiotoxic development of zebrafish larvae may be related to the activation of Notch and apoptosis-related signaling pathways.

Magnesium Oxide Nanomaterial, an Alternative for Commercial Copper Bactericides: Field-Scale Tomato Bacterial Spot Disease Management and Total and Bioavailable Metal Accumulation in Soil.

Copper (Cu) is the most extensively used bactericide worldwide in many agricultural production systems. However, intensive application of Cu bactericide have increased the selection pressure toward Cu-tolerant pathogens, including Xanthomonas perforans, the causal agent of tomato bacterial spot. However, alternatives for Cu bactericides are limited and have many drawbacks including plant damage and inconsistent effectiveness under field conditions. Also, potential ecological risk on nontarget organisms exposed to field runoff containing Cu is high. However, due to lack of alternatives for Cu, it is still widely used in tomato and other crops around the world in both conventional and organic production systems. In this study, a Cu-tolerant X. perforans strain GEV485, which can tolerate eight tested commercial Cu bactericides, was used in all the field trials to evaluate the efficacy of MgO nanomaterial. Four field experiments were conducted to evaluate the impact of intensive application of MgO nanomaterial on tomato bacterial spot disease severity, and one field experiment was conducted to study the impact of soil accumulation of total and bioavailable Cu, Mg, Mn, and Zn. In the first two field experiments, twice-weekly applications of 200 μg/mL MgO significantly reduced disease severity by 29-38% less in comparison to a conventional Cu bactericide Kocide 3000 and 19-30% less in comparison to the water control applied at the same frequency (p = 0.05). The disease severity on MgO twice-weekly was 12-32% less than Kocide 3000 + Mancozeb treatment. Single weekly applications of MgO had 13-19% higher disease severity than twice weekly application of MgO. In the second set of two field trials, twice-weekly applications of MgO at 1000 μg/mL significantly reduced disease severity by 32-40% in comparison to water control applied at the same frequency (p = 0.05). There was no negative yield impact in any of the trials. The third field experiment demonstrated that application of MgO did not result in significant accumulation of total and bioavailable Mg, Mn, Cu, or Zn in the root-associated soil and in soil farther away from the production bed compared to the water control. However, Cu bactericide contributed to significantly higher Mn, Cu, and Zn accumulation in the soil compared to water control (p = 0.05). This study demonstrates that MgO nanomaterial could be an alternative for Cu bactericide and have potential in reducing risks associated with development of tolerant strains and for reducing Cu load in the environment.

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 30μg/ml along with a control for 24h 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 30μg/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.

Effect pesticides to entomopathogen fungi from citrus orchard in vitro

Pesticides are a group of chemicals that are intentionally applied to the environment with the aim of suppressing pests and plant diseases and protecting agricultural products. Most pesticides do not specifically target pests and diseases only during application, but also affect the products produced and human health due to the residue and the effect on non-target pests including entomopathogen. The purpose of this study was to determine the effect of pesticides applied in controlling pests and diseases of citrus plants towards the growth of entomopathogenic fungi in vitro. This test used three active ingredients of pesticides namely Mankozeb (fungicide), Profenofos and Lambda cyhalothrin (insecticides). Dosage of pesticides in the treatments were 0.25 times, 1-time, 2-times of the recommended doses and control (without pesticides). Five types of entomopathogenic fungi used were Metarhizium anisopliae, Hirsutella sp., Beauveria bassiana, Paecilomyces sp. and TB.8 (not yet identified). Each treatment with 3 replications. The size of entomopathogenic fungi showed the influence of pesticides on the growth of entomopathogenic fungi. A quarter dose of profenofos insecticide had the potential to inhibit the growth of all isolates, except M. anisopliae. All isolates did not show significant growth reductions after treated with various doses of Lambda-cyhalothrin insecticide. Mancozeb fungicide had a negative effect on the growth of all entomopathogenic fungi isolates. The highest spore density on the 21st days was Paecilomyces sp. under the Profenofos treatment. Lambda-cyhalothrin did not affect the spore productions in all entomopathogenic fungi isolates. Otherwise, spore production was not observed even at the lowest concentrations of Mancozeb treatment. Differences in the active ingredients of pesticide affected the growth and sporulation of entomopathogen.

Effects of mancozeb on heat Shock protein 70 (HSP70) and its relationship with the thermal physiology of Physalaemus henselii (Peters, 1872) tadpoles (Anura: Leptodactylidae).

Negative impacts on amphibians have been reported due to contamination by agrochemicals. However, until now, no study has tested the effect of the fungicide mancozeb (MZ) on thermal tolerance and its relationship with the expression of heat shock proteins (HSPs). MZ is the best-selling broad-spectrum fungicide in the world, which negatively affects non-target organisms. Here, we tested for the first time the effects of MZ on critical thermal maximum (CTmax) and its relationship to the expression of heat shock protein 70 (HSP70) in tadpoles of Physalameus henselii, a colder-adapted species in southernmost of the Neotropical region. A sublethal concentration of 2mg/L was used. We found that the CTmax of the MZ-treated group was lower than that of the control group. In addition, there was an increase in HSP70 expression in tadpoles exposed to MZ and in tadpoles that underwent heat treatment. However, tadpoles subjected to MZ and heat treatment showed no induced HSP70 protein expression. Our results demonstrated that sublethal doses of the fungicide MZ negatively affected the thermal physiology and heat shock protein expression in tadpoles of P. henselii by inducing an increase in HSP70 concentration and by reducing the critical CTmax supported by tadpoles. It is important to understand the relationship between environmental contamination and physiological thermal limits in our current scenario of high rates of habitat conversion associated with unrestricted use of agrochemicals, as well as the challenging environmental changes induced by global warming.

Mancozeb impairs mitochondrial and bioenergetic activity in Drosophila melanogaster

Mancozeb (MZ) is a broad-spectrum fungicide used worldwide in several crops. Neurological disorders in humans and animals have been associated with exposure to this compound by mechanisms still not fully understood. Drosophila melanogaster represents a reliable model in toxicological studies, presenting genetic and biochemical similarities with mammals. In this study, D. melanogaster flies were exposed for 15 days to MZ through the food (5 and 10 mg/mL). After that period, the efficiency of mitochondrial respiration complexes and metabolic markers were analyzed and evaluated. Flies presented weight loss, lower glucose, trehalose, and glycogen levels, and augmented levels of triglycerides concerning control (non-treated group). Acetyl-CoA Synthetase (ACeCS-1) and Acyl-Coenzyme Synthetase (ACSL1) contents were unchanged by MZ treatment. Mitochondrial respiration of flies was targeted by MZ treatment, evidenced by a decrease in oxygen consumption and bioenergetics rate and inhibition in mitochondrial complexes I/II. These results suppose that an impairment in mitochondrial respiration jointly with reduced levels of energetic substrates might be a mechanism involved in MZ deleterious effects, possibly by the limitation of ATP's availability, necessary for essential cellular processes.

Control of spot on pomegranate fruit in field and phytosanitary quality during postharvest

The pomegranate is a fruit with high productive potential; however, the hot and humid climate favors the occurrence of diseases that cause spots on the fruit peel, reducing their commercial value. Therefore, this study aimed to evaluate different controlling methods of spots on pomegranate fruit under field conditions and their relation with the diseases incidence during the postharvest. The experiment consisted of the following treatments: Test: control group; VM: Vicosa mixture; MZ: Mancozeb; MZ+PC: Plastic cover + Mancozeb; CZ: Carbendazim; KP: Potassium phosphite; P+C: Picoxystrobin + Ciproconazole. Evaluations were performed at 29, 51, 57, 65 and 72 days after application. The treatments MZ, MZ+PC and CZ were more efficient in reducing the severity and incidence on field, with AUDPC-Sev of 67.50; 89.72 and 198.33, respectively. At the post-harvest treatments MZ+PC, MZ, CZ and P+C, the rates of fungal incidence were lower, with 29.2, 37.5, 45.8 and 62.5%, in that order. A linear relationship was found between severity and spots incidence on field with the fungi incidence during postharvest. The Mancozeb treatment was efficient in controlling fruit spots, in addition to reducing the occurrence of diseases during the postharvest of pomegranate.

In vitro and in vivo impairment of embryo implantation by commonly used fungicide Mancozeb

The fungicide Mancozeb is an endocrine-disrupting chemical and the mode of action of Mancozeb on embryo implantation is largely unknown. Mancozeb (1 and 3 μg/ml) significantly reduced Jeg-3 trophoblastic spheroids attachment to endometrial epithelial Ishikawa cells. Mancozeb treatment from gestation day (GD) 1 to GD8 or from GD4 to GD8 significantly lowered the number of implantation sites with higher incidence of morphological abnormalities in the reproductive tissues. However, these were not seen in the treatment from GD1 to GD4. Mancozeb at 30 mg/kg BW/d did not alter the expression of p53, COX-2, or PGFS transcripts in the uterus, but down-regulated the PGES transcript and protein. Mancozeb treatment in human endometrial stromal cells did not alter the decidualization response, but the morphological transformation was impaired. Taken together, exposure to Mancozeb affected embryo implantation probably through the modulation of decidualization and to delineate the exact mode of action needs further investigations.

English

Field experiments were conducted in the Agricultural Research Institute, Uyole, using five susceptible maize varieties during 2013 and 2014 growing seasons. The varieties were used to determine yield losses due to northern leaf blight disease in Mbeya Region of Tanzania. The trials were laid out in two blocks of E. turcicum inoculated and Mancozeb treatment arranged in randomized complete block design in three replicates. Five fungicide sprays were done at weekly interval, starting from 35 days after planting (DAP) while disease inoculation was done twice at 35 and 45 DAP, using whorl placement technique. Data on disease severity index were collected using visual scale of 0-5, and grain yield of each treatment was recorded after harvest and drying. Such data were subjected to analysis of variance, correlation coefficient and coefficient of determination (R&sup2;). Means were separated using Turkey&rsquo;s-Kramer simultaneous test at P&le;0.05. Results indicated that Mancozeb sprays enhanced maize grain yield by 30 to 46.6% and 1000-grain weight by 19 to 24%. Disease severity index range of 78.7 to 95.7% indicated that Bora, Kilima, Situka-1, Staha and TMV-1 varieties were more susceptible to Northern leaf blight (NLB) disease. Yield losses ranged from 46 to 62.8% in grain yield (tons/ha) and 31.9 to 38.9% (g/plot) in 1000-grain weight. Disease severity index assessed at silking dry stage had a strong relationship to yield in all the varieties, but varied from Kilima (r = - 0.7617, R&sup2; = 0.580, P &le; 0.078) in 2014 to Staha (r = - 0.9901, R&sup2; = 0.9803, P &le; 0.001) in 2013 in grain yield. The minimum relationship between1000-grain weight and severity index of NLB was recorded in Staha (r = - 0.9300, R&sup2; = 0.8649, P &le; 0.007) in 2013. The grain yield was enhanced and crop loss models indicated good fitness with strong and reliable validity in all the varieties, and as such can be used to estimate potential losses of maize caused by NLB disease in Mbeya, Tanzania. &nbsp; Key words: Zea mays, northern leaf blight, yield loss, Tanzania. &nbsp

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.

Transport of a manganese/zinc ethylene-bis-dithiocarbamate fungicide may involve pre-synaptic dopaminergic transporters

Mancozeb (MZ), an organic-metal fungicide used predominantly on vegetables and fruits, has been linked to neurodegeneration and behavioral disruptions in a variety of organisms, including humans. Both γ-aminobutyric acid and dopamine neurons appear to be more vulnerable to MZ exposure than other neuronal populations. Based on these observations, we hypothesized that MZ may be differentially transported into these cells through their presynaptic neurotransmitter transporters. To test this, we pretreated Caenorhabditis elegans with transporter antagonists followed by exposure to various concentrations of MZ. Potential neuroprotection was monitored via green fluorescence associated with various neuron populations in transgenic worm strains. Neurodegeneration associated with subacute MZ treatment (30 min) was not altered by transporter antagonist pretreatment. On the other hand, pretreatment with a dopamine transporter antagonist (GBR12909) appeared to protect dopaminergic neurons from chronic (24 h) MZ treatment. These results are consistent with other reports that dopamine transporter levels or activity may modulate toxicity for neurotoxicants.

육묘상 양파 노균병에 대한 몇 가지 살균제의 방제 효과

During the nursery seedlings stage at Muan in 2013, moisture and temperature conditions were favorable for the occurrence of onion downy mildew. Several fungicides were evaluated for controlling onion downy mildew at the stage of seedling. The disease incidence of the untreated control was 51.1%, which was sufficient to evaluate the fungicide efficacy for the control of onion downy mildew. Incidence at the mancozeb treatment (MAN treatment) was 4.4% and it was the highest control value of 91.4%. Incidence at the various fungicides treatment (MIX treatment) consisted of amectotradin plus dimethomorph, floupicolide plus propamocarb HCl, or dimethomorph plus pyraclostrobin was 10.0%, and the control value of the MIX treatment was 80.4%. Among the tested fungicides, amectotradin plus dimethomorph (AME plus DIM treatment) was selected and treated. Incidence of AME plus DIM treatment was 12.2%. There was statistically significant difference among the three different treatments and the untreated control. These results suggest that the application of fungicides on onion nursery seedlings was effective to control the onion downy mildew.

Ethylene bisdithiocarbamate pesticides Maneb and Mancozeb cause metal overload in human colon cells.

Previous studies in our laboratory have shown that ethylene bisdithiocarbamate (EBDC) fungicides Maneb and Mancozeb are equipotent gastrointestinal toxicants that produce cell loss and metal accumulation within HT-29 and Caco2 colon cells. Nabam, MnCl2, CuCl2 and ZnCl2 exposure produced no loss of viability up to 200 μM and increases in metal levels were noted but not to the same extent as Maneb and Mancozeb. EBDC exposure caused increases in copper levels (20-200 μM). Maneb and Mancozeb treatment also caused increases in manganese and zinc concentrations (20-200 μM). Nabam plus MnCl2 and Nabam and MnCl2 plus ZnCl2 caused decreases in viability and increases in metal levels comparable to Maneb and Mancozeb. Decreases in the ratio of reduced glutathione to glutathione disulfide were observed with Maneb and Mancozeb (20-200 μM). Maneb and Mancozeb treatment results in intracellular metal accumulation leading to the oxidative stress. The metal moiety and the organic portion of EBDCs contribute to toxicity.

Different responses of young and expanded lettuce leaves to fungicide Mancozeb: chlorophyll fluorescence, lipid peroxidation, pigments and proline content

This work aimed to study the effects of commercial doses of the fungicide, Mancozeb, on the photosynthetic apparatus of lettuce young leaves (YL) and expanded leaves (EL). Seven days after Mancozeb application, chlorophyll a fluorescence, pigment contents, lipid peroxidation, and proline content were evaluated. Independently of leaf age, Mancozeb treatment reduced the efficiency of photosystem II photochemistry, increased the nonphotochemical quenching and proline content, decreased pigment contents, and induced lipid peroxidation. Moreover, EL showed a more stable photosynthetic apparatus, less prone to oxidative damages compared with YL. The parameters measured proved to be good markers for the rapid and preliminary diagnosis of fungicide toxicity.