Mancozeb Research Articles

Toxicity characterization and environmental risk assessment of Mancozeb on the South American common toad Rhinella arenarum.

Agricultural activity, especially the increasing use of pesticides, is considered one of the main reasons for the decline of amphibian populations. Mancozeb (MCZ) is one of the most used fungicides worldwide, despite its ancient use and toxicity demonstrated in different taxa. However, there is limited information about the effects of MCZ in amphibians, which are keystones of riparian ecosystems. For species conservation purposes, it is essential to identify the most sensitive developmental period(s) of a given species to a xenobiotic. We evaluated the toxicity of a commercial fungicide of mancozeb, (80% active ingredient) on the early development of the common South American toad Rhinella arenarum (Anura, Bufonidae). Embryos from early blastula (S.4) and larvae from complete operculum (S.25) stages were exposed to a wide range of MCZ concentrations during acute, subchronic and chronic exposure (up to 504h) periods. The toxicity profiles for lethal and sublethal effects were performed. At all exposure times, MCZ was more toxic to embryos, for instance, NOEC 504h were 0.01 and 0.05mg MCZ/L for embryos and larvae, respectively. Thus, embryo sensitivity was 5-fold higher than larvae. A Teratogenic Index of 14 indicated the significant teratogenic potential of this fungicide. Among sublethal effects, embryos exhibited a wide range of abnormalities with high incidence. The ecological risk assessment demonstrated that the estimated Risk Quotient value for Rhinella arenarum embryos at chronic exposure was higher than the Level of Concern value, which warns about the potential risk of MCZ for this native species.

Thyroxine modulation of immune toxicity induced by mixture pesticides mancozeb and fipronil in mice

AimThe cross regulation between neuroendocrine system, particularly Hypothalamus-Pituitary-Thyroid (HPT) axis and immune system during embryonic/early neonatal developmental stages shapes the functional attribute of immune response throughout the life. Thus, disruption of immune system was anticipated on exposure to thyroid disrupting pesticides (TDPs) mancozeb (MCZ) and fipronil (FPN) during critical windows of early postnatal days (PND) development. Main methodsMice were exposed to MCZ and FPN as individual (0.5% LD 50 each) and as mixtures (0.25% and 0.5% LD 50 each) from PND 31 (initiation phase of immune response) till PND 60 (Maturation phase). Thyroxine (T4) supplementation was given from PND 51 to PND 60. Assessment was done at PND 61 as well as at PND 91 (adults). Key findingsPlasma level of thyroid hormones (T3 and T4) was reduced but pituitary hormone (TSH) increased till adulthood on exposure to mixture pesticides but not on individual exposure. Mixture pesticides also increased body weight gain and reduced survival rate in adults. Exposure of individual pesticides exert immunotoxicity but more pronounced immune suppression was observed in mixture pesticides exposed group as reflected in reduced relative weight and cellularity in spleen and thymus, reduced in vitro mitogenic (Con A/LPS) response of splenocytes and thymocytes (reduced proliferative index and increased apoptotic/necrotic death). T4 supplementation ameliorated thyroid disruptive and immunotoxic effect of pesticides. SignificanceThe additive/synergistic toxicity as well as hypothyroidism induced by mixture pesticides has produced pronounced immune suppression that reflected till adulthood. Supplementation of T4 prevented thyroid axis disruption mediated immunosuppression.

Comparative effects of Mancozeb and Disulfiram-induced striated muscle myopathies in Long-Evans rats

Dithiocarbamates (DTCs) like mancozeb (MZ) and disulfiram (DS) are used throughout agriculture and medicine and have been implicated in neurotoxicity. Little research has been studied on the reported myopathies caused by these compounds. Their pathogenesis and mechanism of muscle toxicity has not been fully studied. The aim of this study is to investigate if DTCs alter striated muscle tissues in vivo. Long-Evans rats were treated with either MZ or DS followed by analysis of muscle biomarkers and metal levels. DS resulted in increases in serum lactate dehydrogenase (LDH), cardiac troponin, and myoglobin levels. Creatine kinase-MB serum levels decreased. Mancozeb only showed an increase in serum LDH. Both MZ and DS-treatment resulted in altered metal levels in the myocardium but not skeletal muscle. Ultrastructural alterations included damaged mitochondria and myofibril splitting. The presence of multivesicular bodies, and alterations of the intercalated disc were also seen.

Mancozeb exposure during development and lactation periods results in decreased oocyte maturation, fertilization rates, and implantation in the first-generation mice pups: Protective effect of vitamins E and C.

This study aimed to evaluate the mancozeb (MNZ) impact on oocyte maturation of first-generation mice pups as well as their fertilization rate, embryo development, and implantation along with the preventative effect of vitamins E and C. Pregnant mice were randomly divided into six groups: control, vehicle, and MNZ (500 mg/kg body weight (BW)), vitamin E (200 mg/kg BW), MNZ plus vitamin E, MNZ plus vitamin C (100 mg/kg BW), and MNZ plus two vitamins. All treatments were conducted by oral gavage every 2 days from the second day of gestation until the end of lactation. Vitamin treatment was initiated 30 min before receiving MNZ. After birth, first-generation mice pups were kept until adulthood (8-10 W). Adult female mice pups superovulated and then the collected oocytes were examined for nuclear maturity status. After in vitro fertilization of metaphase II oocytes with sperm of the first-generation male mice pups, fertilization rate and embryo development were evaluated over 24 h. Also, the fecundity rate and the number of implanted embryos in vivo were studied on the eighth day of pregnancy. MNZ exposure during embryo development and lactation significantly decreased the total number of collected oocytes, oocyte maturation, fertilization rate, implantation rate, fecundity rate, and embryo development compared with the control group in the first-generation pups. In contrast, vitamin treatments significantly increased these parameters compared to the MNZ group. Reduction in the quality of oocyte, the rate of fertilization, embryo implantation, and development following MNZ exposure could decrease female reproductive success, while coadministration of vitamins E and C could prevent these complications.

Curcumin mitigates mancozeb-induced hepatotoxicity and genotoxicity in rats

Mancozeb (MZ) is a widely used ethylene-bis-dithiocarbamate fungicide in agriculture causing hepatoxic and genotoxic effects in rats. Curcumin (CUR) has various pharmacological effects including antioxidant and anti-inflammatory properties. This study investigated the efficacy of CUR in mitigating MZ-induced hepatotoxicity and genotoxicity in rats. Twenty-four male rats were divided into four equal groups; group I (control) was given carboxymethyl cellulose, group II was orally administered CUR (100 mg/kg b.wt), group III was gavaged with MZ (750 mg/kg b.wt), and group IV was co-treated with MZ and CUR at the same doses daily for 10 weeks. As a result, the concurrent treatment with CUR and MZ minimized the increased levels of liver function markers in serum, lipid peroxidation, pro-inflammatory mediators and DNA damage parameters in liver. In addition, CUR administration improved the depleted markers of hepatic antioxidant status in MZ-treated rats. Moreover, CUR protected the liver against the histological alterations elicited by MZ exposure and also, reduced the immunopositive reactivity of pro-apoptotic p53 in cytoplasm of hepatocytes. The present findings suggest that CUR exerts a significant protective effect against MZ-induced hepatotoxicity and genotoxicity.

Immunomodulatory effect of mancozeb, chlorothalonil, and thiophanate methyl pesticides on macrophage cells

Mancozeb (MZ), chlorothalonil (CT), and thiophanate methyl (TM) are pesticides commonly used in agriculture due to their efficacy, low acute toxicity to mammals, and short environmental persistence. Although the toxic effects of these pesticides have been previously reported, studies regarding their influence on the immune system are limited. As such, this study focused on the immunomodulatory effect of MZ, CT, and TM pesticides on macrophage cells. RAW 264.7 cells were exposed to a range of concentrations (0.1–100 μg/mL) of these pesticides. CT exposure promoted an increase in reactive oxygen species (ROS) and nitric oxide (NO) levels. The MTT and ds-DNA assay results demonstrated that MZ, CT, and TM exposure induced macrophage proliferation. Moreover, MZ, CT, and TM promoted cell cycle arrest at S phase, strongly suggesting macrophage proliferation. The levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IFN-γ) and caspases (caspase 1, 3, and 8) in macrophages exposed to MZ, CT, and TM pesticides increased, whereas the anti-inflammatory cytokine levels decreased. These results suggest that MZ, CT, and TM exert an immunomodulatory effect on the immune system, inducing macrophage activation and enhancing the inflammatory response.

Influence of seed treatment with botanicals and chemicals on storability of Kabuli chickpea (Cicer arietinum L.) varieties

The storage experiment was carried out at Seed Quality and Research Laboratory, Seed Unit (National Seed Project), University of Agricultural Sciences, Dharwad from March 2017 to March 2018 to study the influence of seed treatment with botanicals and chemicals on storability of Kabuli chickpea varieties. Seed quality parameters were significantly influenced among varieties and seed treatment with botanicals and chemicals. Among the treatments, seed treatment with Sprint (Mancozeb 50 % + Carbendazim 25 % WS) @ 2 g per kg of seed or Vitavax power @ 3 g/kg of seed or Sweet flag rhizome @ 10 g/kg of seed maintained seed quality for more than ten months during storage. However, Sweet flag rhizome @ 10 g/kg of seed can be used as alternative to chemicals which is safe, eco-friendly and economically feasible for maintaining seed quality for organic seed growers/producers and seed companies.

Molecular Dynamics Insights for Screening the Ability of Polymers to Remove Pesticides from Water.

The use of pesticides in agriculture is known to have environmental impacts, namely it leads to underground and spring water contamination. Thus, it turns out that nowadays general‐endeavor towards the sustainability of farmer production requires novel strategies to capture pesticides from water and soils. We propose a methodology based on molecular dynamics simulations to identify polymers that are potentially featured to be applied for pesticide remediation in water and soils. We have employed cymoxanil (CYM), glufosinate ammonium (GLF), imidacloprid (IMI) and mancozeb (MAN) as pesticides, and have tested polymers with different characteristics as removing agents. Specifically, we have investigated oligomers of polypropylene (PP), poly(acrylic acid) protonated (PAAH) and deprotonated (PAA), and chitosan protonated (CTH) and deprotonated (CT). It has been found that all oligomers show a certain degree of selectivity concerning the interaction with the tested pesticides.

Vitamins E and C prevent apoptosis of testicular and ovarian tissues following mancozeb exposure in the first-generation mouse pups.

The aim of this study was to evaluate the role of apoptosis in the first-generation pups' testicular and ovarian tissue changes following mancozeb (MNZ) administration during intrauterine and lactating periods and also the preventive effect of the co-administration of vitamins E and C on these changes. Naval Medical Research Institute (NMRI) pregnant mice were randomly divided into six groups: control, vehicle, MNZ, vitamin E plus MNZ, vitamin C plus MNZ and vitamins E and C plus MNZ. Administered doses of MNZ and vitamins E and C were 500, 200 and 100 mg/kg of body weight, respectively. These agents were administered to the animals by oral gavage every 2 days. Vitamin treatment was carried out 30 min prior to MNZ administration. Treatment was started on the second day of gestation and continued until weaning. Separated testes and ovaries of animals were prepared for apoptosis detection by terminal deoxynucleotidyl transferase end-labeling (TUNEL) staining. The percentage of TUNEL-positive cells was reported using the 4,6-diamidino-2-phenylindole method. As compared to the control and vehicle groups, MNZ induced a significant increase ( p < 0.001) in the number of TUNEL-positive cells. The administration of both vitamins E and C alone and together significantly ( p < 0.001) prevented the apoptotic impacts of MNZ. The preventive effect of the co-administration of these vitamins on the ovary was greater compared to the single administration of vitamins E ( p < 0.001) or C ( p < 0.001). Meanwhile, the results revealed the stronger preventive effect of vitamin C as compared to E on testicular tissue ( p < 0.05). The apoptotic impact of MNZ exposure during intrauterine and lactating periods on first-generation testicular and ovarian tissues was significant. The co-administration of vitamins E and C could prevent MNZ-induced testicular and ovarian changes.

Postharvest control of Aspergillus niger in mangos by means of essential oils

The use of essential oil as an alternative mean to synthetic fungicides has been considered in the past years for management of the postharvest decay of fruits in order to ensure more safe and long storage life of these perishable commodities. Aspergillus niger is one of the most dangerous fungal pathogen which can cause postharvest diseases in fresh mangos. The aim of this study was to assess the effectiveness of essential oil from four aromatic plants (Thymus vulgaris, Salvia mirzayanii, Artemisa persica, and Rosmarinus officinalis) in comparison to fungicide ‘Mancozeb’ against A. niger under in vitro and in vivo conditions. After inoculation of mango fruits with an isolate of A. niger followed by curative treatments with essential oil, the main physical and chemical attributes of mangoes were determined under postharvest condition. The in vitro results showed that colonies of A. niger were totally inhibited by application of essential oil of T. vulgaris (at all the tested concentrations) and A. persica (1500 μl/l). While, S. mirzayanii showed the lowest effect at 1000 μl/l if compared with the other essential oils. The results of the in vivo experiments showed that treatments with T. vulgaris and S. mirzayanii essential oil had significant (P<0.05) effects in preventing fruit decay at 1000 μl/l after 10 days of storage, while, R. officinalis essential oil significantly (P<0.05) reduced deterioration of mango fruits at 500 μl/l, followed by A. persica . Rosemary also showed the highest fruit firmness in comparison with other treatments. Also, the essential oils maintained higher chlorophyll content. The results of this work showed that application of essential oil on mangos assurance both a significant preservation on their quality attributes by controlling, at the same time, decaying caused by A. niger during the postharvest phase.

Meta‐analysis of fungicide efficacy on soybean target spot and cost–benefit assessment

Target spot of soybean has spread in Brazil, the southeastern United States and Argentina in the last decade. A collaborative network of field Uniform Fungicide Trials (UFT) in Brazil was created in 2011 to study the target spot control efficacy of fungicides, including azoxystrobin + benzovindiflupyr (AZ_BF), carbendazim (CZM), fluxapyroxad + pyraclostrobin (FLUX_PYRA), epoxiconazole + FLUX_PYRA (EPO_FLUX_PYRA), mancozeb (MZB) and prothioconazole + trifloxystrobin (PROT_TRIF). Network meta‐analysis was used to conduct a quantitative synthesis of UFT data collected from 2012 to 2016 and to evaluate the effects of disease pressure (DP, low ≤ 35% target spot severity in the nontreated control &lt; high) and year of experiment on the overall mean efficacy and yield response to each of the tested fungicides. Based on mean percentage control of target spot severity, the tested fungicides fall into three efficacy groups (EG): high EG, FLUX_PYRA (76.2% control relative to the nontreated control) and EPO_FLUX_PYRA (75.7% control); intermediate EG, PROT_TRIF (66.5% control) and low EG, MZB (49.6% control), AZ_BF (46.7% control) and CZM (32.4% control). DP had a significant effect on yield response. At DPLow, the highest response was due to PROT_TRIF (+342 kg ha−1, +12.8%) and EPO_FLUX_PYRA (+295.5 kg ha−1, +11.2%), whereas at DPHigh, EPO_FLUX_PYRA and FLUX_PYRA outperformed the other treatments, with yield responses of 503 kg ha−1 (+20.2%) and 469 kg ha−1 (+19.1%), respectively. The probability of a positive return on fungicide investment ranged from 0.26 to 0.56 at DPLow and from 0.34 to 0.66 at DPHigh.

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.

Revisiting the Paraquat-Induced Sporadic Parkinson’s Disease-Like Model

Parkinson's disease (PD) is a major neurodegenerative disorder that affects 1-2% of the total global population. Despite its high prevalence and publication of several studies focused on understanding its pathology, an effective treatment that stops and/or reverses the damage to dopaminergic neurons is unavailable. Similar to other neurodegenerative disorders, PD etiology may be linked to several factors, including genetic susceptibility and environmental elements. Regarding environmental factors, several neurotoxic pollutants, including 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), have been identified. Moreover, some pesticides/herbicides, such as rotenone, paraquat (PQ), maneb (MB), and mancozeb (MZ), cause neurotoxicity and induce a PD-like pathology. Based on these findings, several in vitro and in vivo PD-like models have been developed to understand the pathophysiology of PD and evaluate different therapeutic strategies to fight dopaminergic neurodegeneration. 6-OHDA and MPTP are common models used in PD research, and pesticide-based approaches have become secondary models of study. However, some herbicides, such as PQ, are commonly used by farming laborers in developing countries. Thus, the present review summarizes the relevant scientific background regarding the use and effects of chronic exposure to PQ in the context of PD. Similarly, we discuss the relevance of PD-like models developed using this agrochemical compound.

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.

N-acetylcysteine inhibits Mancozeb-induced impairments to the normal development of zebrafish embryos

Mancozeb (MZ), a manganese/zinc-containing ethylene-bis-dithiocarbamate (EBCD) fungicide has been claimed to present low acute toxicity and short environmental persistence, however, its effects on embryogenesis in non-target organisms is unclear. Here, we used zebrafish embryos (5 hpf) to assess the potential embryotoxic effects induced by MZ (up to 72 hpf) as well as the role of reactive oxygen species (ROS) in this process by pre-treatment with a classical antioxidant (N-acetylcysteine, NAC). Markers of reactive oxygen species production (ROS), glutathione (GSH) levels and glutathione S-transferase (GST) activity were measured along with genotoxicity (comet assay), cell death (Acridine Orange) and behavioral parameters (spontaneous movement, touch stimulation and swimming response), in order to determine potential mechanisms of embryotoxicity. According to results, MZ was able to induce morphological abnormalities such as body axis distortion, DNA damage, cell death, increased ROS generation and changes in behavioral endpoints during zebrafish development. All these toxic effects were inhibited by the pre-treatment with NAC indicating a key role of redox unbalance during MZ-induced embryotoxicity. At least in our knowledge, this is the first report on the deleterious effect of MZ to the normal embryogenesis of zebrafish. In addition, the importance of ROS generation during this pathophysiological condition was highlighted.

Joint effects of chlorpyrifos and mancozeb on the terrestrial isopod Porcellionides pruinosus: A multiple biomarker approach.

The exposure to pesticides by nontarget soil biota has long been regarded as a serious downside of modern agricultural regimes and the subject of heated debate. Of utmost relevance is the exposure to pesticide mixtures because their effects have been shown to not necessarily reflect the individual toxicity of their components, and even the simple addition of effects may lead to consequences not clearly anticipated. In the present study, a multiple biomarker approach was employed to identify the mechanistic and time effects underlying several single and mixture treatments of chlorpyrifos (CPF) and mancozeb (MCZ) in juveniles and adults of the terrestrial isopod Porcellionides pruinosus. The effects of the individual pesticides and the mixtures at recommended doses were mostly transitory under these controlled conditions and one-pulse exposure. Whereas imbalances were identified on detoxification and oxidative stress-related enzymes, the isopods generally showed the ability to recover through the end of the experiment. However, juveniles displayed greater vulnerability than adults. Most of the differences between life stages occurred in energy-related parameters where distinct performances and stress-handling behaviors were observed, suggesting higher metabolic costs to juveniles. Our results stress that understanding the time dependence of the underlying mechanisms governing the joint effects of the pesticides can help in assessing and anticipating the effects of the pesticide mixtures. Moreover, we emphasize the importance of taking life stage-related differences into consideration when evaluating the environmental risks of pesticides and pesticide mixtures. Environ Toxicol Chem 2018;37:1446-1457. © 2018 SETAC.

Mancozeb exposure results in manganese accumulation and Nrf2-related antioxidant responses in the brain of common carp Cyprinus carpio.

Manganese (Mn)-containing dithiocarbamates such as Mancozeb (MZ) have been shown to induce oxidative stress-related toxicity in rodents and humans. However, little is known about the neurotoxic effects induced by MZ in fish. In this study, carp (Cyprinus carpio) were exposed to non-lethal waterborne concentrations of MZ, and oxidative stress parameters as well as metal accumulation in fish brains were evaluated. The experimental groups were as follows: control, MZ 5mg/L, and MZ 10mg/L. Fish were exposed for 7days, and then brain was removed and prepared for subsequent analysis of antioxidant enzymes, reactive oxygen species (ROS), and expression of Nrf2 and phosphoNrf2. In parallel, manganese (Mn) levels were evaluated in blood and brain tissues. Mn levels were significantly increased in blood and brain of MZ-exposed carps. In addition, a concentration-dependent increase (p < 0.05) in ROS levels was observed in parallel to increments (p < 0.05) in the activity of major antioxidant enzymes, such as GPx, GR, and GST. On the other hand, significant decreases (p < 0.05) in CAT and SOD activities were observed. The expression of total and phosphorylated forms of Nrf2 was significantly (p < 0.05) upregulated in the brain of carps exposed to Mz when compared to the control, indicating an activation of the Nrf2 antioxidant pathway. Our study showed for the first time the activation of the Nrf2/ARE pathway and bioaccumulation of Mn induced by MZ exposure in fish species, highlighting important mechanisms of action and its toxicological impacts to aquatic organisms.

Exposure of Drosophila melanogaster to Mancozeb Induces Oxidative Damage and Modulates Nrf2 and HSP70/83.

Mancozeb (MZ), a manganese- and zinc-containing ethylene-bis-dithiocarbamate, is a broad-spectrum fungicide. Harmful effects of this fungicide have been reported in nontarget organisms via a not fully understood mechanism. Drosophila melanogaster has provided remarkable contributions for toxicological studies. This work was aimed at evaluating the biochemical targets and implication of oxidative stress in MZ-mediated toxicity in drosophilas. Exposure of flies for fifteen days to MZ at 5 and 10 mg/mL through the diet impaired locomotor performance and induced fly mortality. In parallel, it caused lipid peroxidation and reactive oxygen species (ROS) formation and Mn overload. MZ inhibited superoxide dismutase and inducted catalase and glutathione S-transferase activities. Nitric oxide and reduced glutathione levels were significantly decreased by MZ. Heat shock proteins (HSP70 and HSP83) and Nrf2 mRNA levels were significantly augmented in MZ-exposed flies. Our study reinforced the use of Drosophila melanogaster as a reliable model for the study of biochemical targets of pesticides, and based on our data, MZ induced oxidative damage and Mn accumulation in a concentration-dependent manner. An adaptative cellular state was inducted by the lower concentration of pesticide, possibly contributing to the slighter damage observed.

MANAGEMENT OF RICE BLAST WITH DIFFERENT FUNGICIDES AND POTASSIUM SILICATE UNDER IN VITRO AND IN VIVO CONDITIONS

During 2015 and 2016 cropping season investigations were carried out at Punjab Agricultural University, Ludhiana, India, with the aim to manage rice blast disease by means of different fungicides and potassium silicate under in vitro and in vivo conditions. Fungicides were tested against spore germination of Pyricularia grisea and their efficacy was determined by calculating ED50 and ED90 values. Tricyclazole (Baan 75WP) and Propiconazole (Tilt 25EC) were found to be most fungitoxic compounds and Mancozeb (Indofil Z-78 75WP) was least fungitoxic. Under in vivo conditions, fungicides and potassium silicate were applied at tillering and boot stage. It was found that the fungicide Tricyclazole (Baan 75WP) at 0.06% was most effective and provided disease control of 67.9% followed by Propiconazole (Tilt 25EC) at 0.1% with 60.3% disease control, Azoxystrobin + Difenoconazole (Amistar Top 325SC) at 0.1% with 55.1% disease control and Trifloxystrobin + Tebuconazole (Nativo 75WP) at 0.04% with 53.3% disease control. Difenoconazole (Score 25EC), Tebuconazole (Folicur 25EC) and Mancozeb (Indofil Z-78 2 75WP) were least effective. The potassium silicate applied at 40 and 50 ml/l was found effective against rice blast and significantly increased the grain yield by reducing the toppling of panicles. Thus, it can provide us with an environmentally safe alternative source to rice blast disease management.

Assessment of protective potential of Nigella sativa oil against carbendazim- and/or mancozeb-induced hematotoxicity, hepatotoxicity, and genotoxicity.

Nigella sativa oil (NSO) possesses antioxidant activity. However, its protective role against the hazards of fungicides has been poorly studied. Therefore, the present work aimed at determining the ameliorative potential of NSO against hepatotoxicity induced by carbendazim (CBZ) and/or mancozeb (MNZ) in female rats. In the present study, about 120 adult female Sprague-Dawley rats were randomly divided into eight equal groups. One group of animals was kept as a negative control (Gp. 1); groups 2, 3 and 4 orally received CBZ (200mg/kg body wt) and/or MNZ (300mg/kg body wt) daily for 2weeks (positive groups). In order to assess the hepatoprotective potential of NSO, in comparison with NSO-treated rats (Gp. 5), groups 6, 7 and 8 were CBZ- and/or MNZ-exposed groups pre-treated orally with NSO (2ml/kg body wt) daily for 2weeks (prophylactic groups). All groups were kept further for 15days without medications to observe the withdrawal effect. At the end of exposure and withdrawal periods, the body weight of all experimental rats was recorded and blood samples were collected for hematological, clinico-biochemical, and micronucleus assays. The animals were then sacrificed, and the liver and bone marrow were harvested for oxidative stress bioassay, chromosomal aberrations, DNA fragmentation, and histopathological examinations. The results suggested that pre-treatment with NSO remarkably diminished CBZ- and MNZ-induced macrocytic hypochromic anemia, leukocytosis, lymphocytosis, eosinophilia, and neutropenia. Besides, it also minimized the elevated liver enzymes, lipid peroxidation, micronucleus incidence, DNA damage, and chromosomal aberration frequency. Conversely, NSO significantly stimulated the CBZ- and/or MNZ-induced antioxidant system suppression. The NSO also normalized the hepatic structural architecture. As far as withdrawal effect is concerned, there was almost disappearance of the bad effects of these fungicides and the values were close to the normal range especially with the use of NSO. Ultimately, the results revealed that N. sativa oil is an effective hepatoprotective agent due to its genoprotective and free radical scavenging activities.