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Sample records for biosynthesis inhibiting fungicides

  1. Fenarimol, a Pyrimidine-Type Fungicide, Inhibits Brassinosteroid Biosynthesis

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    Keimei Oh

    2015-07-01

    Full Text Available The plant steroid hormone brassinosteroids (BRs are important signal mediators that regulate broad aspects of plant growth and development. With the discovery of brassinoazole (Brz, the first specific inhibitor of BR biosynthesis, several triazole-type BR biosynthesis inhibitors have been developed. In this article, we report that fenarimol (FM, a pyrimidine-type fungicide, exhibits potent inhibitory activity against BR biosynthesis. FM induces dwarfism and the open cotyledon phenotype of Arabidopsis seedlings in the dark. The IC50 value for FM to inhibit stem elongation of Arabidopsis seedlings grown in the dark was approximately 1.8 ± 0.2 μM. FM-induced dwarfism of Arabidopsis seedlings could be restored by brassinolide (BL but not by gibberellin (GA. Assessment of the target site of FM in BR biosynthesis by feeding BR biosynthesis intermediates indicated that FM interferes with the side chain hydroxylation of BR biosynthesis from campestanol to teasterone. Determination of the binding affinity of FM to purified recombinant CYP90D1 indicated that FM induced a typical type II binding spectrum with a Kd value of approximately 0.79 μM. Quantitative real-time PCR analysis of the expression level of the BR responsive gene in Arabidopsis seedlings indicated that FM induces the BR deficiency in Arabidopsis.

  2. Synergistic mortality between a neonicotinoid insecticide and an ergosterol-biosynthesis-inhibiting fungicide in three bee species.

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    Sgolastra, Fabio; Medrzycki, Piotr; Bortolotti, Laura; Renzi, Maria Teresa; Tosi, Simone; Bogo, Gherardo; Teper, Dariusz; Porrini, Claudio; Molowny-Horas, Roberto; Bosch, Jordi

    2017-06-01

    Neonicotinoid insecticides have been identified as an important factor contributing to bee diversity declines. Nonetheless, uncertainties remain about their impact under field conditions. Most studies have been conducted on Apis mellifera and tested single compounds. However, in agricultural environments, bees are often exposed to multiple pesticides. We explore the synergistic mortality between a neonicotinoid (clothianidin) and an ergosterol-biosynthesis-inhibiting fungicide (propiconazole) in three bee species (A. mellifera, Bombus terrestris, Osmia bicornis) following oral exposure in the laboratory. We developed a new approach based on the binomial proportion test to analyse synergistic interactions. We estimated uptake of clothianidin per foraging bout in honey bees foraging on seed-coated rapeseed fields. We found significant synergistic mortality in all three bee species exposed to non-lethal doses of propiconazole and their respective LD 10 of clothianidin. Significant synergism was only found at the first assessment times in A. mellifera (4 and 24 h) and B. terrestris (4 h), but persisted throughout the experiment (96 h) in O. bicornis. O. bicornis was also the most sensitive species to clothianidin. Our results underscore the importance to test pesticide combinations likely to occur in agricultural environments, and to include several bee species in environmental risk assessment schemes. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  3. Evolution of ergosterol biosynthesis inhibitors as fungicidal against Candida.

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    Ahmad, Aijaz; Khan, Amber; Manzoor, Nikhat; Khan, Luqman A

    2010-01-01

    Azoles target the ergosterol synthesizing enzyme lanosterol 14alpha-demethylase and are a widely applied class of antifungal agents. Unfortunately azoles are generally fungistatic, and resistance to fluconazole is emerging in several fungal pathogens. In contrast to the increasing number of agents for the treatment of invasive fungal infections, discoveries of new antifungal agents with therapeutic value in dermatomycoses are reported only rare. Attention has been drawn to the antimicrobial activity of plants and their active principles due to the challenge of growing incidences of drug-resistant pathogens. Eugenol and methyl eugenol were reported to possess antimycotic properties. To further explore the antifungal activity of these compounds, in vitro studies were conducted on various Candida isolates. Insight studies to mechanism suggested that both eugenol and methyl eugenol exerts their antifungal activity by targeting sterol biosynthesis. Furthermore, it was also observed that additional methyl group to eugenol increases its antifungal activity. The observed fungicidal characteristics of both eugenol and methyl eugenol indicate that both the compounds might be promising antifungal agents defining a new class of antimycotics.

  4. The Fungicidal Activity of Thymol against Fusarium graminearum via Inducing Lipid Peroxidation and Disrupting Ergosterol Biosynthesis

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    Tao Gao

    2016-06-01

    Full Text Available Thymol is a natural plant-derived compound that has been widely used in pharmaceutical and food preservation applications. However, the antifungal mechanism for thymol against phytopathogens remains unclear. In this study, we identified the antifungal action of thymol against Fusarium graminearum, an economically important phytopathogen showing severe resistance to traditional chemical fungicides. The sensitivity of thymol on different F. graminearum isolates was screened. The hyphal growth, as well as conidial production and germination, were quantified under thymol treatment. Histochemical, microscopic, and biochemical approaches were applied to investigate thymol-induced cell membrane damage. The average EC50 value of thymol for 59 F. graminearum isolates was 26.3 μg·mL−1. Thymol strongly inhibited conidial production and hyphal growth. Thymol-induced cell membrane damage was indicated by propidium iodide (PI staining, morphological observation, relative conductivity, and glycerol measurement. Thymol induced a significant increase in malondialdehyde (MDA concentration and a remarkable decrease in ergosterol content. Taken together, thymol showed potential antifungal activity against F. graminearum due to the cell membrane damage originating from lipid peroxidation and the disturbance of ergosterol biosynthesis. These results not only shed new light on the antifungal mechanism of thymol, but also imply a promising alternative for the control of Fusarium head blight (FHB disease caused by F. graminearum.

  5. Influence of new generation fungicides on Saccharomyces cerevisiae growth, grape must fermentation and aroma biosynthesis.

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    Noguerol-Pato, R; Torrado-Agrasar, A; González-Barreiro, C; Cancho-Grande, B; Simal-Gándara, J

    2014-03-01

    The influence of ten new generation fungicides (ametoctradin, benthiavalicarb-isopropyl, boscalid, cyazofamid, dimethomorph, fenhexamid, kresoxim-methyl, mepanipyrim, metrafenone, and pyraclostrobin) on the fermentative activity of Saccharomyces cerevisiae yeast was initially evaluated in pasteurised red must. The presence of ametoctradin, dimethomorph and mepanipyrim seemed to affect sugars-to-ethanol yield in the stationary phase. The same fermentation experiments were carried out for these three fungicides in ecological red must from Vitis vinifera cv. Tempranillo. When ecological must was unfiltered, the fermentative activity of yeasts was unaffected by the presence of these selected fungicides. However, when ecological must was filtered beforehand, a slight decrease of biomass and ethanol production (in terms of biomass-to-ethanol yield and sugars-to-ethanol yield, respectively), as well as a decrease in fruity aroma, were registered with respect to the control wine. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Sterol-inhibiting fungicide impacts on soil microbial ecology in Atlantic Coastal Plain soils

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    White, P. M.; Potter, T. L.; Strickland, T. C.

    2008-12-01

    Seventy-five percent of the peanuts (Arachus hypogaia) produced in the United States are grown in the Atlantic Coastal Plain region. Portions of this area, including Alabama and Georgia, exhibit a subtropical climate that promotes soil-borne plant fungal diseases. Most fields receive repeated fungicide applications during the growing season to suppress the disease causing organisms, such as Sclerotium rolfsii, Rhizoctonia solani, and Cylindrocladium parasiticum. Information regarding fungicide effects on the soil microbial community, with components principally responsible for transformation and fate of fungicides and other soil-applied pesticides, is limited. The objectives of the study were to assess soil microbial community response to (1) varying rates of the sterol-inhibiting fungicide tebuconazole (0, single application, season max, 2x season max), and (2) field rates of the sterol-inhibitors cyproconazole, prothioconazole, tebuconazole, and flutriafol, and thiol-competitor chlorothalonil. The sterol-inhibitors exhibited different half lives, as listed in the FOOTPRINT database, ranging from 1300 d. Chlorothalonil was chosen because it is the most frequently applied fungicide to peanut. Shifts in the fungi, gram positive and gram negative bacteria, were monitored during the experiments using phospholipid fatty acid (PLFA) profiles. Ergosterol levels and pesticide decay rates were also monitored to evaluate the effectiveness of the fungicide and soil residence time, respectively. In the rate study, the highest rate of tebuconazole reduced the fungal biomarker 18:2ω6,9c to 2.6 nmol g-1 dry soil at 17 d, as compared to the control (4.1 nmol g-1 dry soil). However, levels of the fungal PLFA biomarker were similar regardless of rate at 0 and 32 d. The gram negative bacterial PLFA mole percent was greater at 17 d for the two highest rates of tebuconazole, but was similar at 0 and 32 d. Gram positive and fungal mole percents were not affected at any time point

  7. Effect of some fungicides against the growth inhibition of Sclerotinia sclerotiorum mycelial compatibility groups

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    Dalili Alireza

    2015-12-01

    Full Text Available Sclerotinia sclerotiorum (Lib. de Bary, the causal agent of Sclerotinia stem rot, is one of the most important pathogens of Brassica napus L. in northern Iran. In this study, 13 mycelial compatibility groups (MCGs of the fungus were identified among 31 isolates sampled from four regions of Mazandaran province, Iran. Effective fungicides are useful in the integrated management of the disease. So, the effect of tebuconazole, propiconazole, cyproconazole, and Rovral-TS at five doses (0.0001, 0.001, 0.01, 0.1, and 1 ppm was studied on the growth inhibition of S. sclerotiorum as in vitro tests. Maximum inhibition (100% of S. sclerotiorum mycelial growth was obtained by the highest dose (1 ppm of all tested fungicides, as well as by the doses of 0.1 and 0.01 ppm of propiconazole, cyproconazole, and tebuconazole. In this investigation, the reaction of S. sclerotiorum isolates belonging to different MCGs was evaluated against tebuconazole, propiconazole, cyproconazole, and Rovral-TS at their EC50 ranges. The results revealed that there was high variation of S. sclerotiorum MCGs against different fungicides. The inhibition percentage varied between 4.29% and 71.72%.

  8. Fungicide impacts on photosynthesis in crop plants.

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    Petit, Anne-Noëlle; Fontaine, Florence; Vatsa, Parul; Clément, Christophe; Vaillant-Gaveau, Nathalie

    2012-03-01

    Fungicides are widely used to control pests in crop plants. However, it has been reported that these pesticides may have negative effects on crop physiology, especially on photosynthesis. An alteration in photosynthesis might lead to a reduction in photoassimilate production, resulting in a decrease in both growth and yield of crop plants. For example, a contact fungicide such as copper inhibits photosynthesis by destroying chloroplasts, affecting photosystem II activity and chlorophyll biosynthesis. Systemic fungicides such as benzimidazoles, anilides, and pyrimidine are also phytotoxic, whereas azoles stimulate photosynthesis. This article focuses on the available information about toxic effects of fungicides on photosynthesis in crop plants, highlighting the mechanisms of perturbation, interaction, and the target sites of different classes of fungicides. © Springer Science+Business Media B.V. 2012

  9. Apyrase inhibitors enhance the ability of diverse fungicides to inhibit the growth of different plant-pathogenic fungi.

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    Kumar Tripathy, Manas; Weeraratne, Gayani; Clark, Greg; Roux, Stanley J

    2017-09-01

    A previous study has demonstrated that the treatment of Arabidopsis plants with chemical inhibitors of apyrase enzymes increases their sensitivity to herbicides. In this study, we found that the addition of the same or related apyrase inhibitors could potentiate the ability of different fungicides to inhibit the growth of five different pathogenic fungi in plate growth assays. The growth of all five fungi was partially inhibited by three commonly used fungicides: copper octanoate, myclobutanil and propiconazole. However, when these fungicides were individually tested in combination with any one of four different apyrase inhibitors (AI.1, AI.10, AI.13 or AI.15), their potency to inhibit the growth of five fungal pathogens was increased significantly relative to their application alone. The apyrase inhibitors were most effective in potentiating the ability of copper octanoate to inhibit fungal growth, and least effective in combination with propiconazole. Among the five pathogens assayed, that most sensitive to the fungicide-potentiating effects of the inhibitors was Sclerotinia sclerotiorum. Overall, among the 60 treatment combinations tested (five pathogens, four apyrase inhibitors, three fungicides), the addition of apyrase inhibitors increased significantly the sensitivity of fungi to the fungicide treatments in 53 of the combinations. Consistent with their predicted mode of action, inhibitors AI.1, AI.10 and AI.13 each increased the level of propiconazole retained in one of the fungi, suggesting that they could partially block the ability of efflux transporters to remove propiconazole from these fungi. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  10. Probenazole treatment inhibits anthocyanins biosynthesis via ...

    African Journals Online (AJOL)

    It has been found that anthocyanins were accumulated in Arabidopsis under drought or salt stress. In this study, such accumulation was found to be inhibited by external applied probenazole (3-allyloxy-1, 2-benzisothiazole-1,1-dioxide, PBZ), which is the active ingredient in oryzemate used for the protection of rice from ...

  11. Enhanced ethanol production, volatile compound biosynthesis and fungicide removal during growth of a newly isolated Saccharomyces cerevisiae strain on enriched pasteurized grape musts

    Energy Technology Data Exchange (ETDEWEB)

    Sarris, Dimitris; Kotseridis, Yorgos; Galiotou-Panayotou, Maria; Papanikolaou, Seraphim [Department of Food Science and Technology, Agricultural University of Athens (Greece); Linga, Maria [Oinognosia, Wine analysis and consulting, Kiato (Greece)

    2009-02-15

    The kinetic behavior of a newly isolated Saccharomyces cerevisiae strain, grown on pasteurized grape musts enriched with industrial sugars, was studied after the addition of various concentrations [0.0 (reference), 0.4 and 2.4 mg/L] of the fungicide quinoxyfen to the medium. Batch-flask cultures were carried out. Significant quantities of biomass (10.0{+-}0.8 g/L) were produced regardless of quinoxyfen addition to the medium; therefore, the addition of the fungicide did not seriously inhibit biomass production. Ethanol was synthesized in very high quantities in all trials (highest concentrations 106.4-119.2 g/L). A slight decrease of ethanol production in terms of both absolute value and conversion yield of ethanol produced per sugar consumed was, however, observed when the quinoxyfen concentration was increased. The addition of quinoxyfen led to significantly lower ethylic ester levels, which also pertains to the acetates analyzed in this study. Fusel alcohol synthesis seemed to be activated when 0.4 mg/L quinoxyfen was added, but at 2.4 mg/L of added fungicide, no statistically significant differences were observed compared with the control trial. Volatile acid levels did not present a uniform trend in relation with the added fungicide. Finally, the fermentation was accompanied by a significant reduction of the fungicide concentration (79-82 wt% fungicide removal). (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  12. Increasing the Fungicidal Action of Amphotericin B by Inhibiting the Nitric Oxide-Dependent Tolerance Pathway

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    Kim Vriens

    2017-01-01

    Full Text Available Amphotericin B (AmB induces oxidative and nitrosative stresses, characterized by production of reactive oxygen and nitrogen species, in fungi. Yet, how these toxic species contribute to AmB-induced fungal cell death is unclear. We investigated the role of superoxide and nitric oxide radicals in AmB’s fungicidal activity in Saccharomyces cerevisiae, using a digital microfluidic platform, which enabled monitoring individual cells at a spatiotemporal resolution, and plating assays. The nitric oxide synthase inhibitor L-NAME was used to interfere with nitric oxide radical production. L-NAME increased and accelerated AmB-induced accumulation of superoxide radicals, membrane permeabilization, and loss of proliferative capacity in S. cerevisiae. In contrast, the nitric oxide donor S-nitrosoglutathione inhibited AmB’s action. Hence, superoxide radicals were important for AmB’s fungicidal action, whereas nitric oxide radicals mediated tolerance towards AmB. Finally, also the human pathogens Candida albicans and Candida glabrata were more susceptible to AmB in the presence of L-NAME, pointing to the potential of AmB-L-NAME combination therapy to treat fungal infections.

  13. Triazole Fungicides Inhibit Zebrafish Hatching by Blocking the Secretory Function of Hatching Gland Cells.

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    De la Paz, Javiera F; Beiza, Natalia; Paredes-Zúñiga, Susana; Hoare, Misque S; Allende, Miguel L

    2017-04-04

    In animals, hatching represents the transition point from a developing embryo to a free-living individual, the larva. This process is finely regulated by many endogenous and environmental factors and has been shown to be sensitive to a variety of chemical agents. It is commonly evaluated in bioassays in order to establish the effects of different agents on early development and reproductive capabilities in fish and other aquatic animals. In fish, the breakdown of the chorion is achieved by the secretion of choriolysin by hatching gland cells (HGCs) into the perivitelline space (PVS), coupled with spontaneous movements of the developing larva. In this work, we used zebrafish to assay the effects of a family of widely used agrochemicals-triazoles Triadimefon (FON), Triadimenol (NOL) and free triazole (1,2,4-T)-on hatching success. We found a strong inhibition of hatching by triazole exposure which was correlated with morphological changes and a reduction in the secretory function of the HGCs. As a consequence, the release of choriolytic enzymes by HGCs was reduced. We also found that HGC secretion reduction after exposure to FON can be rescued by co-incubation with a dopamine D2 receptor antagonist but not by antagonists of the D1-like receptors. This suggests a specific pathway through which this family of fungicides may be impairing a critical event in the fish life cycle.

  14. Curcumin improves alcoholic fatty liver by inhibiting fatty acid biosynthesis.

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    Guo, Chang; Ma, Jingfan; Zhong, Qionghong; Zhao, Mengyuan; Hu, Tianxing; Chen, Tong; Qiu, Longxin; Wen, Longping

    2017-08-01

    Alcoholic fatty liver is a threat to human health. It has been long known that abstinence from alcohol is the most effective therapy, other effective therapies are not available for the treatment in humans. Curcumin has a great potential for anti-oxidation and anti-inflammation, but the effect on metabolic reconstruction remains little known. Here we performed metabolomic analysis by gas chromatography/mass spectrometry and explored ethanol pathogenic insight as well as curcumin action pattern. We identified seventy-one metabolites in mouse liver. Carbohydrates and lipids were characteristic categories. Pathway analysis results revealed that ethanol-induced pathways including biosynthesis of unsaturated fatty acids, fatty acid biosynthesis and pentose and glucuronate interconversions were suppressed by curcumin. Additionally, ethanol enhanced galactose metabolism and pentose phosphate pathway. Glyoxylate and dicarboxylate metabolism and pyruvate metabolism were inhibited in mice fed ethanol diet plus curcumin. Stearic acid, oleic acid and linoleic acid were disease biomarkers and therapical biomarkers. These results reflect the landscape of hepatic metabolism regulation. Our findings illustrate ethanol pathological pathway and metabolic mechanism of curcumin therapy. Copyright © 2017. Published by Elsevier Inc.

  15. Proteolytic Pathways Induced by Herbicides That Inhibit Amino Acid Biosynthesis

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    Zulet, Amaia; Gil-Monreal, Miriam; Villamor, Joji Grace; Zabalza, Ana; van der Hoorn, Renier A. L.; Royuela, Mercedes

    2013-01-01

    Background The herbicides glyphosate (Gly) and imazamox (Imx) inhibit the biosynthesis of aromatic and branched-chain amino acids, respectively. Although these herbicides inhibit different pathways, they have been reported to show several common physiological effects in their modes of action, such as increasing free amino acid contents and decreasing soluble protein contents. To investigate proteolytic activities upon treatment with Gly and Imx, pea plants grown in hydroponic culture were treated with Imx or Gly, and the proteolytic profile of the roots was evaluated through fluorogenic kinetic assays and activity-based protein profiling. Results Several common changes in proteolytic activity were detected following Gly and Imx treatment. Both herbicides induced the ubiquitin-26 S proteasome system and papain-like cysteine proteases. In contrast, the activities of vacuolar processing enzymes, cysteine proteases and metacaspase 9 were reduced following treatment with both herbicides. Moreover, the activities of several putative serine protease were similarly increased or decreased following treatment with both herbicides. In contrast, an increase in YVADase activity was observed under Imx treatment versus a decrease under Gly treatment. Conclusion These results suggest that several proteolytic pathways are responsible for protein degradation upon herbicide treatment, although the specific role of each proteolytic activity remains to be determined. PMID:24040092

  16. The fungicide Pristine® inhibits mitochondrial function in vitro but not flight metabolic rates in honey bees.

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    Campbell, Jacob B; Nath, Rachna; Gadau, Juergen; Fox, Trevor; DeGrandi-Hoffman, Gloria; Harrison, Jon F

    2016-03-01

    Honey bees and other pollinators are exposed to fungicides that act by inhibiting fungal mitochondria. Here we test whether a common fungicide (Pristine®) inhibits the function of mitochondria of honeybees, and whether consumption of ecologically-realistic concentrations can cause negative effects on the mitochondria of flight muscles, or the capability for flight, as judged by CO2 emission rates and thorax temperatures during flight. Direct exposure of mitochondria to Pristine® levels above 5 ppm strongly inhibited mitochondrial oxidation rates in vitro. However, bees that consumed pollen containing Pristine® at ecologically-realistic concentrations (≈ 1 ppm) had normal flight CO2 emission rates and thorax temperatures. Mitochondria isolated from the flight muscles of the Pristine®-consuming bees had higher state 3 oxygen consumption rates than control bees, suggesting that possibly Pristine®-consumption caused compensatory changes in mitochondria. It is likely that the lack of a strong functional effect of Pristine®-consumption on flight performance and the in vitro function of flight muscle mitochondria results from maintenance of Pristine® levels in the flight muscles at much lower levels than occur in the food, probably due to metabolism and detoxification. As Pristine® has been shown to negatively affect feeding rates and protein digestion of honey bees, it is plausible that Pristine® consumption negatively affects gut wall function (where mitochondria may be exposed to higher concentrations of Pristine®). Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Studies on inhibition of respiratory cytochrome bc1 complex by the fungicide pyrimorph suggest a novel inhibitory mechanism.

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    Yu-Mei Xiao

    Full Text Available The respiratory chain cytochrome bc1 complex (cyt bc1 is a major target of numerous antibiotics and fungicides. All cyt bc1 inhibitors act on either the ubiquinol oxidation (QP or ubiquinone reduction (QN site. The primary cause of resistance to bc1 inhibitors is target site mutations, creating a need for novel agents that act on alternative sites within the cyt bc1 to overcome resistance. Pyrimorph, a synthetic fungicide, inhibits the growth of a broad range of plant pathogenic fungi, though little is known concerning its mechanism of action. In this study, using isolated mitochondria from pathogenic fungus Phytophthora capsici, we show that pyrimorph blocks mitochondrial electron transport by affecting the function of cyt bc1. Indeed, pyrimorph inhibits the activities of both purified 11-subunit mitochondrial and 4-subunit bacterial bc1 with IC50 values of 85.0 μM and 69.2 μM, respectively, indicating that it targets the essential subunits of cyt bc1 complexes. Using an array of biochemical and spectral methods, we show that pyrimorph acts on an area near the QP site and falls into the category of a mixed-type, noncompetitive inhibitor with respect to the substrate ubiquinol. In silico molecular docking of pyrimorph to cyt b from mammalian and bacterial sources also suggests that pyrimorph binds in the vicinity of the quinol oxidation site.

  18. In vivo inhibition of polyamine biosynthesis and growth in tobacco ovary tissues

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    Slocum, R. D.; Galston, A. W.

    1985-01-01

    Post fertilization growth of tobacco ovary tissues treated with inhibitors of polyamine (PA) biosynthesis was examined in relation to endogenous PA titers and the activities of arginine decarboxylase (ADC, EC 4.1.1.19) and ornithine decarboxylase (ODC, EC 4.1.1.17). DL-alpha-Difluoromethylornithine (DFMO) and DL-alpha-difluoromethylarginine (DFMA), specific, irreversible ("suicide") inhibitors of ODC and ADC in vitro, were used to modulate PA biosynthesis in excised flowers. ODC represented >99% of the total decarboxylase activity in tobacco ovaries. In vivo inhibition of ODC with DFMO resulted in a significant decrease in PA titers, ovary fresh weight and protein content. Simultaneous inhibition of both decarboxylases by DFMO and DFMA produced only a marginally greater depression in growth and PA titers, indicating that ODC activity is rate-limiting for PA biosynthesis in these tissues. Paradoxically, DFMA alone inhibited PA biosynthesis, not as a result of a specific inhibition of ADC, but primarily through the inactivation of ODC. In vivo inhibition of ODC by DFMA appears to result from arginase-mediated hydrolysis of this inhibitor to urea and DFMO, the suicide substrate for ODC. Putrescine conjugates in tobacco appear to function as a storage form of this amine which, upon hydrolysis, may contribute to Put homeostasis during growth.

  19. In-Vitro Inhibition of Pythium ultimum, Fusarium graminearum, and Rhizoctonia solani by a Stabilized Lactoperoxidase System alone and in Combination with Synthetic Fungicides

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    Zachariah R. Hansen

    2017-11-01

    Full Text Available Advances in enzyme stabilization and immobilization make the use of enzymes for industrial applications increasingly feasible. The lactoperoxidase (LPO system is a naturally occurring enzyme system with known antimicrobial activity. Stabilized LPO and glucose oxidase (GOx enzymes were combined with glucose, potassium iodide, and ammonium thiocyanate to create an anti-fungal formulation, which inhibited in-vitro growth of the plant pathogenic oomycete Pythium ultimum, and the plant pathogenic fungi Fusarium graminearum and Rhizoctonia solani. Pythium ultimum was more sensitive than F. graminearum and R. solani, and was killed at LPO and GOx concentrations of 20 nM and 26 nM, respectively. Rhizoctonia solani and F. graminearum were 70% to 80% inhibited by LPO and GOx concentrations of 242 nM and 315 nM, respectively. The enzyme system was tested for compatibility with five commercial fungicides as co-treatments. The majority of enzyme + fungicide co-treatments resulted in additive activity. Synergism ranging from 7% to 36% above the expected additive activity was observed when P. ultimum was exposed to the enzyme system combined with Daconil® (active ingredient (AI: chlorothalonil 29.6%, GardenTech, Lexington, KY, USA, tea tree oil, and mancozeb at select fungicide concentrations. Antagonism was observed when the enzyme system was combined with Tilt® (AI: propiconazole 41.8%, Syngenta, Basel, Switzerland at one fungicide concentration, resulting in activity 24% below the expected additive activity at that concentration.

  20. Oleanolic acid and ursolic acid inhibit peptidoglycan biosynthesis in Streptococcus mutans UA159

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    Soon-Nang Park

    2015-06-01

    Full Text Available In this study, we revealed that OA and UA significantly inhibited the expression of most genes related to peptidoglycan biosynthesis in S. mutans UA159. To the best of our knowledge, this is the first report to introduce the antimicrobial mechanism of OA and UA against S. mutans.

  1. Effect of inhibition of biosynthesis of phenylpropanoids on sessile oak somatic embryogenesis

    Czech Academy of Sciences Publication Activity Database

    Cvikrová, Milena; Malá, J.; Hrubcová, Marie; Eder, Josef; Zoń, J.; Macháčková, Ivana

    2003-01-01

    Roč. 41, č. 3 (2003), s. 251-259 ISSN 0981-9428 R&D Projects: GA MŠk LN00A081 Institutional research plan: CEZ:AV0Z5038910 Keywords : Inhibition of phenylpropanoid biosynthesis * Somatic embryogenesis * Oak Subject RIV: CE - Biochemistry Impact factor: 1.729, year: 2003

  2. Sequence variation in the CYP51 gene of Blumeria graminis associated with resistance to sterol demethylase inhibiting fungicides.

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    Wyand, R A; Brown, J K M

    2005-08-01

    Resistance to sterol 14alpha-demethylase inhibiting fungicides (DMIs) has been correlated with mutations in the CYP51 gene, which encodes the target enzyme eburicol 14alpha-demethylase. To test the hypothesis that variation in the CYP51 gene explains variation for DMI sensitivity in barley and wheat powdery mildew species, this gene was sequenced from isolates of Blumeria graminis f.sp. hordei (Bgh) and f.sp. tritici (Bgt), respectively, which differed in their responses to DMIs in agricultural populations in the UK. Two single-nucleotide mutations in the CYP51 gene, which resulted in the amino acid substitutions Y136F and K147Q, were detected. K147Q is a novel mutation present only in Bgh isolates expressing very high levels of resistance. Sequence analysis of the CYP51 gene from the progeny of a cross between DMI-sensitive and resistant Bgh isolates showed that both mutations segregate with resistance, which is consistent with CYP51 controlling a major portion of DMI resistance. However, genetic analysis of resistance to the DMI triadimenol indicates that mutation of the CYP51 gene is not the only mechanism of resistance operating in B. graminis.

  3. Autoxidated linolenic acid inhibits aflatoxin biosynthesis in Aspergillus flavus via oxylipin species.

    Science.gov (United States)

    Yan, Shijuan; Liang, Yating; Zhang, Jindan; Chen, Zhuang; Liu, Chun-Ming

    2015-08-01

    Aflatoxins produced by Aspergillus species are among the most toxic and carcinogenic compounds in nature. Although it has been known for a long time that seeds with high oil content are more susceptible to aflatoxin contamination, the role of fatty acids in aflatoxin biosynthesis remains controversial. Here we demonstrate in A. flavus that both the saturated stearic acid (C18:0) and the polyunsaturated linolenic acid (C18:3) promoted aflatoxin production, while C18:3, but not C18:0, inhibited aflatoxin biosynthesis after exposure to air for several hours. Further experiments showed that autoxidated C18:3 promoted mycelial growth, sporulation, and kojic acid production, but inhibited the expression of genes in the AF biosynthetic gene cluster. Mass spectrometry analyses of autoxidated C18:3 fractions that were able to inhibit aflatoxin biosynthesis led to the identification of multiple oxylipin species. These results may help to clarify the role of fatty acids in aflatoxin biosynthesis, and may explain why controversial results have been obtained for fatty acids in the past. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Glucose inhibits cardiac muscle maturation through nucleotide biosynthesis

    OpenAIRE

    Nakano, Haruko; Minami, Itsunari; Braas, Daniel; Pappoe, Herman; Wu, Xiuju; Sagadevan, Addelynn; Vergnes, Laurent; Fu, Kai; Morselli, Marco; Dunham, Christopher; Ding, Xueqin; Stieg, Adam Z; Gimzewski, James K; Pellegrini, Matteo; Clark, Peter M

    2017-01-01

    The heart switches its energy substrate from glucose to fatty acids at birth, and maternal hyperglycemia is associated with congenital heart disease. However, little is known about how blood glucose impacts heart formation. Using a chemically defined human pluripotent stem-cell-derived cardiomyocyte differentiation system, we found that high glucose inhibits the maturation of cardiomyocytes at genetic, structural, metabolic, electrophysiological, and biomechanical levels by promoting nucleoti...

  5. Acaricide, fungicide and drug interactions in honey bees (Apis mellifera.

    Directory of Open Access Journals (Sweden)

    Reed M Johnson

    Full Text Available BACKGROUND: Chemical analysis shows that honey bees (Apis mellifera and hive products contain many pesticides derived from various sources. The most abundant pesticides are acaricides applied by beekeepers to control Varroa destructor. Beekeepers also apply antimicrobial drugs to control bacterial and microsporidial diseases. Fungicides may enter the hive when applied to nearby flowering crops. Acaricides, antimicrobial drugs and fungicides are not highly toxic to bees alone, but in combination there is potential for heightened toxicity due to interactive effects. METHODOLOGY/PRINCIPAL FINDINGS: Laboratory bioassays based on mortality rates in adult worker bees demonstrated interactive effects among acaricides, as well as between acaricides and antimicrobial drugs and between acaricides and fungicides. Toxicity of the acaricide tau-fluvalinate increased in combination with other acaricides and most other compounds tested (15 of 17 while amitraz toxicity was mostly unchanged (1 of 15. The sterol biosynthesis inhibiting (SBI fungicide prochloraz elevated the toxicity of the acaricides tau-fluvalinate, coumaphos and fenpyroximate, likely through inhibition of detoxicative cytochrome P450 monooxygenase activity. Four other SBI fungicides increased the toxicity of tau-fluvalinate in a dose-dependent manner, although possible evidence of P450 induction was observed at the lowest fungicide doses. Non-transitive interactions between some acaricides were observed. Sublethal amitraz pre-treatment increased the toxicity of the three P450-detoxified acaricides, but amitraz toxicity was not changed by sublethal treatment with the same three acaricides. A two-fold change in the toxicity of tau-fluvalinate was observed between years, suggesting a possible change in the genetic composition of the bees tested. CONCLUSIONS/SIGNIFICANCE: Interactions with acaricides in honey bees are similar to drug interactions in other animals in that P450-mediated detoxication

  6. Acaricide, fungicide and drug interactions in honey bees (Apis mellifera).

    Science.gov (United States)

    Johnson, Reed M; Dahlgren, Lizette; Siegfried, Blair D; Ellis, Marion D

    2013-01-01

    Chemical analysis shows that honey bees (Apis mellifera) and hive products contain many pesticides derived from various sources. The most abundant pesticides are acaricides applied by beekeepers to control Varroa destructor. Beekeepers also apply antimicrobial drugs to control bacterial and microsporidial diseases. Fungicides may enter the hive when applied to nearby flowering crops. Acaricides, antimicrobial drugs and fungicides are not highly toxic to bees alone, but in combination there is potential for heightened toxicity due to interactive effects. Laboratory bioassays based on mortality rates in adult worker bees demonstrated interactive effects among acaricides, as well as between acaricides and antimicrobial drugs and between acaricides and fungicides. Toxicity of the acaricide tau-fluvalinate increased in combination with other acaricides and most other compounds tested (15 of 17) while amitraz toxicity was mostly unchanged (1 of 15). The sterol biosynthesis inhibiting (SBI) fungicide prochloraz elevated the toxicity of the acaricides tau-fluvalinate, coumaphos and fenpyroximate, likely through inhibition of detoxicative cytochrome P450 monooxygenase activity. Four other SBI fungicides increased the toxicity of tau-fluvalinate in a dose-dependent manner, although possible evidence of P450 induction was observed at the lowest fungicide doses. Non-transitive interactions between some acaricides were observed. Sublethal amitraz pre-treatment increased the toxicity of the three P450-detoxified acaricides, but amitraz toxicity was not changed by sublethal treatment with the same three acaricides. A two-fold change in the toxicity of tau-fluvalinate was observed between years, suggesting a possible change in the genetic composition of the bees tested. Interactions with acaricides in honey bees are similar to drug interactions in other animals in that P450-mediated detoxication appears to play an important role. Evidence of non-transivity, year-to-year variation

  7. Inhibition of somatotroph growth and growth hormone biosynthesis by activin in vitro

    DEFF Research Database (Denmark)

    Billestrup, Nils; González-Manchón, C; Potter, E

    1990-01-01

    Activin-A, a homodimeric protein composed of two inhibin beta A-subunits, was first isolated from gonadal fluids based upon its ability to stimulate FSH secretion and biosynthesis, but was also observed to suppress GH secretion. The present report describes the effects of activin on the biosynthe......Activin-A, a homodimeric protein composed of two inhibin beta A-subunits, was first isolated from gonadal fluids based upon its ability to stimulate FSH secretion and biosynthesis, but was also observed to suppress GH secretion. The present report describes the effects of activin...... the effect of activin on FSH secretion, did not reverse the effect of activin on GH biosynthesis. Treatment of somatotrophs with activin for 3 days completely inhibited the growth-promoting effect of GRF on somatotrophs. However, no effect of activin on GRF-stimulated expression of the c-fos protooncogene...... was observed. These data demonstrate that activin, in addition to its stimulatory effect on FSH secretion, is able to inhibit both expression of GH and growth of somatotropic cells....

  8. Cyproheptadine metabolites inhibit proinsulin and insulin biosynthesis and insulin release in isolated rat pancreatic islets

    International Nuclear Information System (INIS)

    Chow, S.A.; Falany, J.L.; Fischer, L.J.

    1989-01-01

    The contribution of drug metabolites to cyproheptadine (CPH)-induced alterations in endocrine pancreatic beta-cells was investigated by examining the inhibitory activity of CPH and its biotransformation products, desmethylcyproheptadine (DMCPH), CPH-epoxide and DMCPH-epoxide, on hormone biosynthesis and secretion in pancreatic islets isolated from 50-day-old rats. Measurement of (pro)insulin (proinsulin and insulin) synthesis using incorporation of 3H-leucine showed that DMCPH-epoxide, DMCPH and CPH-epoxide were 22, 10 and 4 times, respectively, more potent than CPH in inhibiting hormone synthesis. The biosynthesis of (pro)insulin was also inhibited by CPH and DMCPH-epoxide in islets isolated from 21-day-old rat fetuses. The inhibitory action of CPH and its metabolites was apparently specific for (pro)insulin, and the synthesis of other islet proteins was not affected. Other experiments showed the metabolites of CPH were active in inhibiting glucose-stimulated insulin secretion but were less potent than the parent drug in producing this effect. CPH and its structurally related metabolites, therefore, have differential inhibitory activities on insulin synthesis and release. The observation that CPH metabolites have higher potency than CPH to inhibit (pro)insulin synthesis, when considered with published reports on the disposition of the drug in rats, indicate that CPH metabolites, particularly DMCPH-epoxide, are primarily responsible for the insulin depletion observed when the parent compound is given to fetal and adult animals

  9. Molecular characterization and detection of mutations associated with resistance to succinate dehydrogenase inhibiting (SDHI) fungicides in Alternaria solani

    Science.gov (United States)

    Early blight, caused by Alternaria solani, is an economically important foliar disease of potato in several production areas of the United States. Few potato cultivars possess resistance to early blight, therefore, the application of fungicides is a primary means of achieving disease control. Previo...

  10. Policosanol inhibits cholesterol biosynthesis and enhances low density lipoprotein processing in cultured human fibroblasts.

    Science.gov (United States)

    Menendez, R; Fernandez, S I; Del Rio, A; Gonzalez, R M; Fraga, V; Amor, A M; Mas, R M

    1994-01-01

    Policosanol is a mixture of aliphatic primary alcohols isolated and purified from sugar cane wax, that induces cholesterol-lowering effects in experimental models and human beings. When human lung fibroblasts were incubated with policosanol for 48 hours prior to the experiment, a dose dependent inhibition of 14C-acetate incorporation into total cholesterol was observed, whereas labeled mevalonate incorporation was not inhibited. Even when cholesterol synthesis was not strongly inhibited, low density lipoprotein (LDL) processing was markedly enhanced. Thus, LDL binding, internalization and degradation were significantly increased after policosanol treatment. In addition, despite the fact that'cholesterol generation was not inhibited at the lowest dose of policosanol assayed, LDL processing was significantly increased. The current data indicate that policosanol inhibits cholesterol synthesis at the earliest steps of the cholesterol biosynthetic pathway. On the other hand, this study suggests that the increase in LDL processing may be partially explained by the inhibition of cholesterol biosynthesis, even though an sterol-independent mechanism might be responsible for the enhancement of LDL-receptor activity.

  11. Treatment with Antibiotics that Interfere with Peptidoglycan Biosynthesis Inhibits Chloroplast Division in the Desmid Closterium

    Science.gov (United States)

    Matsumoto, Hiroko; Takechi, Katsuaki; Sato, Hiroshi; Takio, Susumu; Takano, Hiroyoshi

    2012-01-01

    Charophytes is a green algal group closely related to land plants. We investigated the effects of antibiotics that interfere with peptidoglycan biosynthesis on chloroplast division in the desmid Closterium peracerosum–strigosum–littorale complex. To detect cells just after division, we used colchicine, which inhibits Closterium cell elongation after division. Although normal Closterium cells had two chloroplasts before and after cell division, cells treated with ampicillin, D-cycloserine, or fosfomycin had only one chloroplast after cell division, suggesting that the cells divided without chloroplast division. The antibiotics bacitracin and vancomycin showed no obvious effect. Electron microscopic observation showed that irregular-shaped chloroplasts existed in ampicillin-treated Closterium cells. Because antibiotic treatments resulted in the appearance of long cells with irregular chloroplasts and cell death, we counted cell types in the culture. The results suggested that cells with one chloroplast appeared first and then a huge chloroplast was generated that inhibited cell division, causing elongation followed by cell death. PMID:22815801

  12. Auxin-Induced Ethylene Triggers Abscisic Acid Biosynthesis and Growth Inhibition1

    Science.gov (United States)

    Hansen, Hauke; Grossmann, Klaus

    2000-01-01

    The growth-inhibiting effects of indole-3-acetic acid (IAA) at high concentration and the synthetic auxins 7-chloro-3-methyl-8-quinolinecarboxylic acid (quinmerac), 2-methoxy-3,6-dichlorobenzoic acid (dicamba), 4-amino-3,6,6-trichloropicolinic acid (picloram), and naphthalene acetic acid, were investigated in cleavers (Galium aparine). When plants were root treated with 0.5 mm IAA, shoot epinasty and inhibition of root and shoot growth developed during 24 h. Concomitantly, 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity, and ACC and ethylene production were transiently stimulated in the shoot tissue within 2 h, followed by increases in immunoreactive (+)-abscisic acid (ABA) and its precursor xanthoxal (xanthoxin) after 5 h. After 24 h of treatment, levels of xanthoxal and ABA were elevated up to 2- and 24-fold, relative to control, respectively. In plants treated with IAA, 7-chloro-3-methyl-8-quinolinecarboxylic acid, naphthalene acetic acid, 2-methoxy-3,6-dichlorobenzoic acid, and 4-amino-3,6,6-trichloropicolinic acid, levels of ethylene, ACC, and ABA increased in close correlation with inhibition of shoot growth. Aminoethoxyvinyl-glycine and cobalt ions, which inhibit ethylene synthesis, decreased ABA accumulation and growth inhibition, whereas the ethylene-releasing ethephon promoted ABA levels and growth inhibition. In accordance, tomato mutants defective in ethylene perception (never ripe) did not produce the xanthoxal and ABA increases and growth inhibition induced by auxins in wild-type plants. This suggests that auxin-stimulated ethylene triggers ABA accumulation and the consequent growth inhibition. Reduced catabolism most probably did not contribute to ABA increase, as indicated by immunoanalyses of ABA degradation and conjugation products in shoot tissue and by pulse experiments with [3H]-ABA in cell suspensions of G. aparine. In contrast, studies using inhibitors of ABA biosynthesis (fluridone, naproxen, and tungstate), ABA

  13. Fibrillar collagen inhibits cholesterol biosynthesis in human aortic smooth muscle cells.

    Science.gov (United States)

    Ferri, Nicola; Roncalli, Elisa; Arnaboldi, Lorenzo; Fenu, Simone; Andrukhova, Olena; Aharinejad, Seyedhossein; Camera, Marina; Tremoli, Elena; Corsini, Alberto

    2009-10-01

    Integrin-mediated cell adhesion to type I fibrillar collagen regulates gene and protein expression, whereas little is known of its effect on lipid metabolism. In the present study, we examined the effect of type I fibrillar collagen on cholesterol biosynthesis in human aortic smooth muscle cells (SMCs). SMCs were cultured on either fibrillar or monomer collagen for 48 hours and [(14)C]-acetate incorporation into cholesterol was evaluated. Fibrillar collagen reduced by 72.9+/-2.6% cholesterol biosynthesis without affecting cellular cholesterol levels. Fibrillar collagen also reduced 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoA) promoter activity (-72.6+/-7.3%), mRNA (-58.7+/-6.4%), protein levels (-35.5+/-8.5%), and enzyme activity (-37.7+/-2.2%). Intracellular levels of the active form of sterol regulatory element binding proteins (SREBP) 1a was decreased by 60.7+/-21.7% in SMCs cultured on fibrillar collagen, whereas SREBP2 was not significantly affected (+12.1+/-7.1%). The overexpression of the active form of SREBP1a rescued the downregulation of fibrillar collagen on HMG-CoA reductase levels. Blocking antibody to alpha2 integrin partially reversed the downregulation of HMG-CoA reductase mRNA expression. Finally, fibrillar collagen led to an intracellular accumulation of unprenylated Ras. Our study demonstrated that alpha2 beta 1 integrin interaction with fibrillar collagen affected the expression of HMG-CoA reductase, which led to the inhibition of cholesterol biosynthesis in human SMCs.

  14. Evolution of cross-resistance to medical triazoles in Aspergillus fumigatus through selection pressure of environmental fungicides.

    Science.gov (United States)

    Zhang, Jianhua; van den Heuvel, Joost; Debets, Alfons J M; Verweij, Paul E; Melchers, Willem J G; Zwaan, Bas J; Schoustra, Sijmen E

    2017-09-27

    Resistance to medical triazoles in Aspergillus fumigatus is an emerging problem for patients at risk of aspergillus diseases. There are currently two presumed routes for medical triazole-resistance selection: (i) through selection pressure of medical triazoles when treating patients and (ii) through selection pressure from non-medical sterol-biosynthesis-inhibiting (SI) triazole fungicides which are used in the environment. Previous studies have suggested that SI fungicides can induce cross-resistance to medical triazoles. Therefore, to assess the potential of selection of resistance to medical triazoles in the environment, we assessed cross-resistance to three medical triazoles in lineages of A. fumigatus from previous work where we applied an experimental evolution approach with one of five different SI fungicides to select for resistance. In our evolved lines we found widespread cross-resistance indicating that resistance to medical triazoles rapidly arises through selection pressure of SI fungicides. All evolved lineages showed similar evolutionary dynamics to SI fungicides and medical triazoles, which suggests that the mutations inducing resistance to both SI fungicides and medical triazoles are likely to be the same. Whole-genome sequencing revealed that a variety of mutations were putatively involved in the resistance mechanism, some of which are in known target genes. © 2017 The Author(s).

  15. Effect of fungicides on Wyoming big sagebrush seed germination

    Science.gov (United States)

    Robert D. Cox; Lance H. Kosberg; Nancy L. Shaw; Stuart P. Hardegree

    2011-01-01

    Germination tests of Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle & Young [Asteraceae]) seeds often exhibit fungal contamination, but the use of fungicides should be avoided because fungicides may artificially inhibit germination. We tested the effect of seed-applied fungicides on germination of Wyoming big sagebrush at 2 different...

  16. Ultraviolet light inhibition of phytochrome-induced flavonoid biosynthesis and DNA photolyase formation in mustard cotyledons (Sinapis alba L.)

    International Nuclear Information System (INIS)

    Buchholz, G.; Ehmann, B.; Wellmann, E.

    1995-01-01

    In cotyledons of etiolated mustard (Sinapis alba L.) seedlings, phytochrome-far-red-absorbing form-induced flavonoid biosynthesis was found to be inhibited by short-term ultraviolet (UV) irradiations. UV inhibition was shown for the synthesis of quercetin, anthocyanin, and also for the accumulation of the mRNA for chalcone synthase, the key enzyme of this pathway. The UV effect was more pronounced on flavonoid biosynthesis, a process that selectively occurs in the epidermal layers, than on the synthesis of mRNA for chlorophyll a/b-binding protein localized in the mesophyll tissue. These UV inhibitory effects were accompanied by cyclobutane pyrimidine dimer (CPD) formation showing a linear fluence-response relationship. CPD formation and UV inhibition of flavonoid biosynthesis was found to be partially reversible by blue/UV-A light via DNA photolyase (PRE), allowing photoreactivation of the DNA by splitting of CPDs, which are the cause of the UV effect. Like flavonoid formation PRE was also induced by the far-red-absorbing form of phytochrome and induction was inhibited by UV. A potential risk of inhibition, in response to solar UV-B irradiation, was shown for anthocyanin formation. This inhibition, however, occurred only if photoreactivation was experimentally reduced. The PRE activity present in the etiolated seedlings (further increasing about 5-fold during light acclimatization) appears to be sufficient to prevent the persistence of CPDs even under conditions of high solar irradiation

  17. Differential effects of fenpropimorph and fenhexamid, two sterol biosynthesis inhibitor fungicides, on arbuscular mycorrhizal development and sterol metabolism in carrot roots.

    Science.gov (United States)

    Campagnac, Estelle; Fontaine, Joël; Sahraoui, Anissa Lounès-Hadj; Laruelle, Frédéric; Durand, Roger; Grandmougin-Ferjani, Anne

    2008-12-01

    Sterols composition of transformed carrot roots incubated in presence of increasing concentrations of fenpropimorph (0.02; 0.2; 2mgl(-1)) and fenhexamid (0.02; 0.2; 2; 20mgl(-1)), colonized or not by Glomus intraradices was determined. In mycorrhizal roots treated with fenpropimorph, normal Delta(5)-sterols were replaced by unusual compounds such as 9beta,19-cyclopropylsterols (24-methylpollinastanol), Delta(8,14)-sterols (ergosta-8,14-dienol, stigmasta-8,14-dienol), Delta(8)-sterols (Delta(8) sitosterol) and Delta(7)-sterols (ergosta-7,22-dienol). After application of fenpropimorph, a drastic reduction of the mycorrhizal root growth, root colonization and extraradical fungal development was observed. Application of fenhexamid did not modify sterol profiles and the total colonization of roots. But the arbuscule frequency of the fungal partner was significantly affected. Comparison of the effects caused by the tested fungicides indicates that the usual phytosterols may be involved in symbiosis development. Indeed, observed modifications of root sterols composition could explain the high fenpropimorph toxicity to the AM symbiosis. However, the absence of sterolic modifications in the roots treated with fenhexamid could account for its more limited impact on mycorrhization.

  18. Inhibition of cholesterol biosynthesis in cultured fibroblasts by D003, a mixture of very long chain saturated fatty acids.

    Science.gov (United States)

    Menéndez, R; Más, R; Amor, A M; Rodeiros, I; Gonzalez, R M; Alfonso, J L

    2001-10-01

    The present study was undertaken to investigate the effects of D003, a mixture of very long chain saturated fatty acids isolated and purified from sugar cane wax, on cholesterol biosynthesis in cultured fibroblasts. Cholesterol biosynthesis is regulated through feedback regulation of at least two sequentially acting enzymes, 3-hydroxy-3-methyl coenzyme A (HMG-CoA) synthase and reductase. They are up-regulated when sterol levels fall and down-regulated when sterol levels rise. The exposure of cultured fibroblasts to a lipid-depleted medium (LDM) and D003 (0.05-50 microg ml(-1)) for 12 h inhibited, in a dose-dependent manner, cholesterol biosynthesis from 14C-labelled acetate (33-68%). The addition of D003 at concentrations inhibiting cholesterol biosynthesis from labelled acetate significantly decreased incorporation of radioactivity from 3H2O into sterols, but not from 14C-mevalonate. These data indicate that D003 inhibits cholesterol biosynthesis by interfering with early steps of cholesterol biosynthetic pathway. We reasoned that D003 acts directly on HMG-CoA reductase, the main regulatory enzyme of cholesterol biosynthetic pathway. However, when enzyme activity was measured in cell extracts in the presence of various concentrations of D003 (0.5-50 microg ml(-1)), reductase activity was not inhibited. Thus, there was no evidence for a competitive or non-competitive inhibition of enzyme activity by D003. Treatment with D003 significantly suppressed (68%) the enzyme up-regulation when cells were cultured in LDM, which suggests a depression of de novo synthesis of HMG-CoA reductase and/or a stimulation of its degradation. However, since the suppressive action of D003 on cholesterol biosynthesis was observed in metabolic conditions under which synthase up-regulation was also enhanced, we cannot rule out a possible effect of D003 on HMG-CoA synthase. Thus, further studies are needed to clarify the precise mechanism of the inhibitory effect of D003 on cholesterol

  19. ROLE OF POLYAMINES IN INHIBITION OF ETHYLENE BIOSYNTHESIS AND THEIR EFFECTS ON RICE ANTHER CULTURE DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Iswari S. Dewi

    2016-10-01

    Full Text Available The polyamines such as putrescine, spermidine, and spermine were reported to increase green plant regeneration in rice anther culture. Low response of anther culture of rice sub-species indica may be improved with the addition of putrescine in the culture media. Four experiments were conducted to study the role of polyamines in inhibition of ethylene biosynthesis and their effects on rice anther culture development. Anthers of two subspecies of rice, indica (IR64, Krowal, Jatiluhur and japonica (Taipei 309 were cultured onto media supplemented with putrescine (N6P and without putrescine (N6. Youngpanicles containing the anthers at mid-to-late nucleate microspores were cold pretreated at 5 + 2°C and incubated in the dark for 8 days before the anthers were cultured. Resultsshowed that medium without putrescine produced an earlier senescence of indica rice anther than that of japonica. The addition of 10-3 M putrescine into the culture media inhibited ethylene biosynthesis as anther senescence delayed, increased the three polyamines contents, and decreased the ACC content as well as ACC oxydase activity in anther-derived calli. In the anther and anther-derived calli of subspecies indica, the totalpolyamines content was lower (10.14 nM g-1 anther and 8.48 nM g-1 calli than that of subspecies japonica (12.61 nM g-1 anther and 10.16 nM g-1 calli, whereas the ethylene production was higher (32.31 nM g-1 anther and 2.48 nM g-1 calli than the japonica (31.68 nM g-1 anther and 1.76 nM g-1 calli. This study suggests that application of 10-3 M putrescine in anther culture of rice subspecies indica improves androgenesis by inhibitingearly senescence of cultured anthers and enhancing embryo or callus formation from microspores.

  20. Potential mechanisms underlying response to effects of the fungicide pyrimethanil from gene expression profiling in Saccharomyces cerevisiae.

    Science.gov (United States)

    Gil, Fátima N; Becker, Jörg D; Viegas, Cristina A

    2014-06-11

    Pyrimethanil is a fungicide mostly applied in vineyards. When misused, residue levels detected in grape must or in the environment may be of concern. The present work aimed to analyze mechanisms underlying response to deleterious effects of pyrimethanil in the eukaryotic model Saccharomyces cerevisiae. Pyrimethanil concentration-dependent effects at phenotypic (inhibition of growth) and transcriptomic levels were examined. For transcriptional profiling, analysis focused on two sublethal exposure conditions that inhibited yeast growth by 20% or 50% compared with control cells not exposed to the fungicide. Gene expression modifications increased with the magnitude of growth inhibition, in numbers and fold-change of differentially expressed genes and in diversity of over-represented functional categories. These included mostly biosynthesis of arginine and sulfur amino acids metabolism, as well as energy conservation, antioxidant response, and multidrug transport. Several pyrimethanil-responsive genes encoded proteins sharing significant homology with proteins from phytopathogenic fungi and ecologically relevant higher eukaryotes.

  1. Activation of stress signalling pathways enhances tolerance of fungi to chemical fungicides and antifungal proteins.

    Science.gov (United States)

    Hayes, Brigitte M E; Anderson, Marilyn A; Traven, Ana; van der Weerden, Nicole L; Bleackley, Mark R

    2014-07-01

    Fungal disease is an increasing problem in both agriculture and human health. Treatment of human fungal disease involves the use of chemical fungicides, which generally target the integrity of the fungal plasma membrane or cell wall. Chemical fungicides used for the treatment of plant disease, have more diverse mechanisms of action including inhibition of sterol biosynthesis, microtubule assembly and the mitochondrial respiratory chain. However, these treatments have limitations, including toxicity and the emergence of resistance. This has led to increased interest in the use of antimicrobial peptides for the treatment of fungal disease in both plants and humans. Antimicrobial peptides are a diverse group of molecules with differing mechanisms of action, many of which remain poorly understood. Furthermore, it is becoming increasingly apparent that stress response pathways are involved in the tolerance of fungi to both chemical fungicides and antimicrobial peptides. These signalling pathways such as the cell wall integrity and high-osmolarity glycerol pathway are triggered by stimuli, such as cell wall instability, changes in osmolarity and production of reactive oxygen species. Here we review stress signalling induced by treatment of fungi with chemical fungicides and antifungal peptides. Study of these pathways gives insight into how these molecules exert their antifungal effect and also into the mechanisms used by fungi to tolerate sub-lethal treatment by these molecules. Inactivation of stress response pathways represents a potential method of increasing the efficacy of antifungal molecules.

  2. Impact of fungicides on weed growth

    Directory of Open Access Journals (Sweden)

    Nordmeyer, Henning

    2014-02-01

    Full Text Available The study has shown that fungicides influence the growth of weeds. The competition against crops will be substantially reduced. Bioassays in a climate chamber variation in temperature as well as different lightning phases and microplot trials under semi field levels were carried out to investigate the influence of fungicides on weed growth. Selected weed species (Alopecurus myosuroides, Viola arvensis, Galium aparine, Stellaria media, Lamium purpureum have been examined with different dose rates of fungicides (Adexar, Bravo 500, Diamant, Crupozin flüssig. Weed species showed a different sensitivity. There were leaf discoloration, contractions and growth inhibition. In some cases using common practise dose rates of fungicides more than 70% growth inhibition could be estimated 14 days after application in comparison to the untreated control. Effects were much stronger in bioassays than in semi field trials.

  3. Inhibition of phenylpropanoid biosynthesis in Artemisia annua L.: a novel approach to reduce oxidative browning in plant tissue culture.

    Directory of Open Access Journals (Sweden)

    Andrew Maxwell Phineas Jones

    Full Text Available Oxidative browning is a common and often severe problem in plant tissue culture systems caused by the accumulation and oxidation of phenolic compounds. The current study was conducted to investigate a novel preventative approach to address this problem by inhibiting the activity of the phenylalanine ammonia lyase enzyme (PAL, thereby reducing the biosynthesis of phenolic compounds. This was accomplished by incorporating 2-aminoindane-2-phosphonic acid (AIP, a competitive PAL inhibitor, into culture media of Artemisia annua as a model system. Addition of AIP into culture media resulted in significant reductions in visual tissue browning, a reduction in total phenol content, as well as absorbance and autoflourescence of tissue extracts. Reduced tissue browning was accompanied with a significant increase in growth on cytokinin based medium. Microscopic observations demonstrated that phenolic compounds accumulated in discrete cells and that these cells were more prevalent in brown tissue. These cells were highly plasmolyzed and often ruptured during examination, demonstrating a mechanism in which phenolics are released into media in this system. These data indicate that inhibiting phenylpropanoid biosynthesis with AIP is an effective approach to reduce tissue browning in A. annua. Additional experiments with Ulmus americana and Acer saccharum indicate this approach is effective in many species and it could have a wide application in systems where oxidative browning restricts the development of biotechnologies.

  4. Inhibition of phenylpropanoid biosynthesis in Artemisia annua L.: a novel approach to reduce oxidative browning in plant tissue culture.

    Science.gov (United States)

    Jones, Andrew Maxwell Phineas; Saxena, Praveen Kumar

    2013-01-01

    Oxidative browning is a common and often severe problem in plant tissue culture systems caused by the accumulation and oxidation of phenolic compounds. The current study was conducted to investigate a novel preventative approach to address this problem by inhibiting the activity of the phenylalanine ammonia lyase enzyme (PAL), thereby reducing the biosynthesis of phenolic compounds. This was accomplished by incorporating 2-aminoindane-2-phosphonic acid (AIP), a competitive PAL inhibitor, into culture media of Artemisia annua as a model system. Addition of AIP into culture media resulted in significant reductions in visual tissue browning, a reduction in total phenol content, as well as absorbance and autoflourescence of tissue extracts. Reduced tissue browning was accompanied with a significant increase in growth on cytokinin based medium. Microscopic observations demonstrated that phenolic compounds accumulated in discrete cells and that these cells were more prevalent in brown tissue. These cells were highly plasmolyzed and often ruptured during examination, demonstrating a mechanism in which phenolics are released into media in this system. These data indicate that inhibiting phenylpropanoid biosynthesis with AIP is an effective approach to reduce tissue browning in A. annua. Additional experiments with Ulmus americana and Acer saccharum indicate this approach is effective in many species and it could have a wide application in systems where oxidative browning restricts the development of biotechnologies.

  5. Pre-termination in aflR of Aspergillus sojae inhibits aflatoxin biosynthesis.

    Science.gov (United States)

    Matsushima, K; Chang, P K; Yu, J; Abe, K; Bhatnagar, D; Cleveland, T E

    2001-05-01

    The aflR gene product is the main transcriptional regulator of aflatoxin biosynthesis in Aspergillus parasiticus and Aspergillus flavus. Although A. sojae strains do not produce aflatoxins, they do have an aflR homologue. When compared with the aflR of A. parasiticus, the A. sojae gene contains two mutations: an HAHA motif and a premature stop codon. To investigate the functionality of the A. sojae aflR gene product, we used a GAL4 one-hybrid system in yeast. The transcription-activating activity of AflR from A. sojae was 15% of that from A. parasiticus. The introduction of an additional aflR from A. sojae into an A. parasiticus strain did not affect aflatoxin productivity. A hybrid aflR comprising the amino-terminal region of A. sojae aflR and the carboxy-terminal region of A. parasiticus aflR suppressed the effect associated with pre-termination of the A. sojae AflR. We conclude that the premature stop codon of the A. sojae aflR is the key to its functionality and leads to prevention of aflatoxin biosynthesis through loss of the transcription of aflatoxin biosynthesis-related genes.

  6. Artemether Exhibits Amoebicidal Activity against Acanthamoeba castellanii through Inhibition of the Serine Biosynthesis Pathway.

    Science.gov (United States)

    Deng, Yihong; Ran, Wei; Man, Suqin; Li, Xueping; Gao, Hongjian; Tang, Wei; Tachibana, Hiroshi; Cheng, Xunjia

    2015-08-01

    Acanthamoeba sp. parasites are the causative agents of Acanthamoeba keratitis, fatal granulomatous amoebic encephalitis, and cutaneous infections. However, there are currently no effective drugs for these organisms. Here, we evaluated the activity of the antimalarial agent artemether against Acanthamoeba castellanii trophozoites and identified potential targets of this agent through a proteomic approach. Artemether exhibited in vitro amoebicidal activity in a time- and dose-dependent manner and induced ultrastructural modification and cell apoptosis. The iTRAQ quantitative proteomic analysis identified 707 proteins that were differentially expressed after artemether treatment. We focused on phosphoglycerate dehydrogenase and phosphoserine aminotransferase in the serine biosynthesis pathway because of their importance to the growth and proliferation of protozoan and cancer cells. The expression of these proteins in Acanthamoeba was validated using quantitative real-time PCR and Western blotting after artemether treatment. The changes in the expression levels of phosphoserine aminotransferase were consistent with those of phosphoglycerate dehydrogenase. Therefore, the downregulation of phosphoserine aminotransferase may be due to the downregulation of phosphoglycerate dehydrogenase. Furthermore, exogenous serine might antagonize the activity of artemether against Acanthamoeba trophozoites. These results indicate that the serine biosynthesis pathway is important to amoeba survival and that targeting these enzymes would improve the treatment of Acanthamoeba infections. Artemether may be used as a phosphoglycerate dehydrogenase inhibitor to control or block Acanthamoeba infections. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  7. Annual Fungicide Loadings

    Data.gov (United States)

    U.S. Environmental Protection Agency — Pesticides, Herbicides, Fungicides...etc, are used for a variety of purposes, including control of household, lawn, and garden pests; for control of mosquitoes and...

  8. Arginine Deprivation Inhibits the Warburg Effect and Upregulates Glutamine Anaplerosis and Serine Biosynthesis in ASS1-Deficient Cancers

    Directory of Open Access Journals (Sweden)

    Jeff Charles Kremer

    2017-01-01

    Full Text Available Targeting defects in metabolism is an underutilized strategy for the treatment of cancer. Arginine auxotrophy resulting from the silencing of argininosuccinate synthetase 1 (ASS1 is a common metabolic alteration reported in a broad range of aggressive cancers. To assess the metabolic effects that arise from acute and chronic arginine starvation in ASS1-deficient cell lines, we performed metabolite profiling. We found that pharmacologically induced arginine depletion causes increased serine biosynthesis, glutamine anaplerosis, oxidative phosphorylation, and decreased aerobic glycolysis, effectively inhibiting the Warburg effect. The reduction of glycolysis in cells otherwise dependent on aerobic glycolysis is correlated with reduced PKM2 expression and phosphorylation and upregulation of PHGDH. Concurrent arginine deprivation and glutaminase inhibition was found to be synthetic lethal across a spectrum of ASS1-deficient tumor cell lines and is sufficient to cause in vivo tumor regression in mice. These results identify two synthetic lethal therapeutic strategies exploiting metabolic vulnerabilities of ASS1-negative cancers.

  9. Candida albicans Inhibits Pseudomonas aeruginosa Virulence through Suppression of Pyochelin and Pyoverdine Biosynthesis

    Science.gov (United States)

    Lopez-Medina, Eduardo; Fan, Di; Coughlin, Laura A.; Ho, Evi X.; Lamont, Iain L.; Reimmann, Cornelia; Hooper, Lora V.; Koh, Andrew Y.

    2015-01-01

    Bacterial-fungal interactions have important physiologic and medical ramifications, but the mechanisms of these interactions are poorly understood. The gut is host to trillions of microorganisms, and bacterial-fungal interactions are likely to be important. Using a neutropenic mouse model of microbial gastrointestinal colonization and dissemination, we show that the fungus Candida albicans inhibits the virulence of the bacterium Pseudomonas aeruginosa by inhibiting P. aeruginosa pyochelin and pyoverdine gene expression, which plays a critical role in iron acquisition and virulence. Accordingly, deletion of both P. aeruginosa pyochelin and pyoverdine genes attenuates P. aeruginosa virulence. Heat-killed C. albicans has no effect on P. aeruginosa, whereas C. albicans secreted proteins directly suppress P. aeruginosa pyoverdine and pyochelin expression and inhibit P. aeruginosa virulence in mice. Interestingly, suppression or deletion of pyochelin and pyoverdine genes has no effect on P. aeruginosa’s ability to colonize the GI tract but does decrease P. aeruginosa’s cytotoxic effect on cultured colonocytes. Finally, oral iron supplementation restores P. aeruginosa virulence in P. aeruginosa and C. albicans colonized mice. Together, our findings provide insight into how a bacterial-fungal interaction can modulate bacterial virulence in the intestine. Previously described bacterial-fungal antagonistic interactions have focused on growth inhibition or colonization inhibition/modulation, yet here we describe a novel observation of fungal-inhibition of bacterial effectors critical for virulence but not important for colonization. These findings validate the use of a mammalian model system to explore the complexities of polymicrobial, polykingdom infections in order to identify new therapeutic targets for preventing microbial disease. PMID:26313907

  10. Proteomic profile of the plant-pathogenic oomycete Phytophthora capsici in response to the fungicide pyrimorph.

    Science.gov (United States)

    Pang, Zhili; Chen, Lei; Miao, Jianqiang; Wang, Zhiwen; Bulone, Vincent; Liu, Xili

    2015-09-01

    Pyrimorph is a novel fungicide from the carboxylic acid amide (CAA) family used to control plant-pathogenic oomycetes such as Phytophthora capsici. The proteomic response of P. capsici to pyrimorph was investigated using the iTRAQ technology to determine the target site of the fungicide and potential biomarker candidates of drug efficacy. A total of 1336 unique proteins were identified from the mycelium of wild-type P. capsici isolate (Hd3) and two pyrimorph-resistant mutants (R3-1 and R3-2) grown in the presence or absence of pyrimorph. Comparative analysis revealed that the three P. capsici isolates Hd3, R3-1, and R3-2 produced 163, 77, and 13 unique proteins, respectively, which exhibited altered levels of abundance in response to the pyrimorph treatment. Further investigations, using Cluster of Orthologous Groups of Proteins (COG) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis identified 35 proteins related to the mode of action of pyrimorph against P. capsici and 62 proteins involved in the stress response of P. capsici to pyrimorph. Many of the proteins with altered expression were associated with glucose and energy metabolism. Biochemical analysis using d-[U-(14) C]glucose verified the proteomics data, suggesting that the major mode of action of pyrimorph in P. capsici is the inhibition of cell wall biosynthesis. These results also illustrate that proteomics approaches are useful tools for determining the pathways targeted by novel fungicides as well as for evaluating the tolerance of plant pathogens to environmental challenges, such as the presence of fungicides. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Effects of inhibiting CoQ10 biosynthesis with 4-nitrobenzoate in human fibroblasts.

    Directory of Open Access Journals (Sweden)

    Catarina M Quinzii

    Full Text Available Coenzyme Q(10 (CoQ(10 is a potent lipophilic antioxidant in cell membranes and a carrier of electrons in the mitochondrial respiratory chain. We previously characterized the effects of varying severities of CoQ(10 deficiency on ROS production and mitochondrial bioenergetics in cells harboring genetic defects of CoQ(10 biosynthesis. We observed a unimodal distribution of ROS production with CoQ(10 deficiency: cells with <20% of CoQ(10 and 50-70% of CoQ(10 did not generate excess ROS while cells with 30-45% of CoQ(10 showed increased ROS production and lipid peroxidation. Because our previous studies were limited to a small number of mutant cell lines with heterogeneous molecular defects, here, we treated 5 control and 2 mildly CoQ(10 deficient fibroblasts with varying doses of 4-nitrobenzoate (4-NB, an analog of 4-hydroxybenzoate (4-HB and inhibitor of 4-para-hydroxybenzoate:polyprenyl transferase (COQ2 to induce a range of CoQ(10 deficiencies. Our results support the concept that the degree of CoQ(10 deficiency in cells dictates the extent of ATP synthesis defects and ROS production and that 40-50% residual CoQ(10 produces maximal oxidative stress and cell death.

  12. Prevention of cholesterol gallstones by inhibiting hepatic biosynthesis and intestinal absorption of cholesterol

    Science.gov (United States)

    Wang, Helen H; Portincasa, Piero; de Bari, Ornella; Liu, Kristina J; Garruti, Gabriella; Neuschwander-Tetri, Brent A; Wang, David Q.-H

    2013-01-01

    Cholesterol cholelithiasis is a multifactorial disease influenced by a complex interaction of genetic and environmental factors, and represents a failure of biliary cholesterol homeostasis in which the physical-chemical balance of cholesterol solubility in bile is disturbed. The primary pathophysiologic event is persistent hepatic hypersecretion of biliary cholesterol, which has both hepatic and small intestinal components. The majority of the environmental factors are probably related to Western-type dietary habits, including excess cholesterol consumption. Laparoscopic cholecystectomy, one of the most commonly performed surgical procedures in the US, is nowadays a major treatment for gallstones. However, it is invasive and can cause surgical complications, and not all patients with symptomatic gallstones are candidates for surgery. The hydrophilic bile acid, ursodeoxycholic acid (UDCA) has been employed as first-line pharmacological therapy in a subgroup of symptomatic patients with small, radiolucent cholesterol gallstones. Long-term administration of UDCA can promote the dissolution of cholesterol gallstones. However, the optimal use of UDCA is not always achieved in clinical practice because of failure to titrate the dose adequately. Therefore, the development of novel, effective, and noninvasive therapies is crucial for reducing the costs of health care associated with gallstones. In this review, we summarize recent progress in investigating the inhibitory effects of ezetimibe and statins on intestinal absorption and hepatic biosynthesis of cholesterol, respectively, for the treatment of gallstones, as well as in elucidating their molecular mechanisms by which combination therapy could prevent this very common liver disease worldwide. PMID:23419155

  13. Induction of the PDH bypass and upregulation of the ALDH7B4 in plants treated with herbicides inhibiting amino acid biosynthesis.

    Science.gov (United States)

    Gil-Monreal, Miriam; Zabalza, Ana; Missihoun, Tagnon D; Dörmann, Peter; Bartels, Dorothea; Royuela, Mercedes

    2017-11-01

    Imazamox and glyphosate represent two classes of herbicides that inhibit the activity of acetohydroxyacid synthase in the branched-chain amino acid biosynthesis pathway and the activity of 5-enolpyruvylshikimate-3-phosphate synthase in the aromatic amino acid biosynthesis pathway, respectively. However, it is still unclear how imazamox and glyphosate lead to plant death. Both herbicides inhibit amino-acid biosynthesis and were found to induce ethanol fermentation in plants, but an Arabidopsis mutant deficient in alcohol dehydrogenase 1 was neither more susceptible nor more resistant than the wild-type to the herbicides. In this study, we investigated the effects of the amino acid biosynthesis inhibitors, imazamox and glyphosate, on the pyruvate dehydrogenase bypass reaction and fatty acid metabolism in A. thaliana. We found that the pyruvate dehydrogenase bypass was upregulated following the treatment by the two herbicides. Our results suggest that the Arabidopsis aldehyde dehydrogenase 7B4 gene might be participating in the pyruvate dehydrogenase bypass reaction. We evaluated the potential role of the aldehyde dehydrogenase 7B4 upon herbicide treatment in the plant defence mechanism. Plants that overexpressed the ALDH7B4 gene accumulated less soluble sugars, starch, and fatty acids and grew better than the wild-type after herbicide treatment. We discuss how the upregulation of the ALDH7B4 alleviates the effects of the herbicides, potentially through the detoxification of the metabolites produced in the pyruvate dehydrogenase bypass. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Sensitivity of Colletotrichum acutatum Isolates to Selected Fungicides

    Directory of Open Access Journals (Sweden)

    Barbora Jílková

    2015-01-01

    Full Text Available Laboratory tests of six isolates of the pathogen Colletotrichum acutatum from different host plants demonstrated the varying sensitivity of pathogen with regard to mycelium growth and conidial germination after treatment with seven fungicides containing various active ingredients. None of the evaluated isolates was tolerant to the selected active ingredients in the fungicides. In tests of mycelium growth sensitivity, isolates from lupin and strawberry were most frequently identified as the most sensitive of all evaluated fungicides. The safflower isolate, on the other hand, most frequently exhibited the lowest reaction to fungicides. Differences in conidial germination of individual isolates were not detected in fungicides with the active ingredients dithianon, folpet and mancozeb, for which inhibition reached 100% in almost all isolates. The most significant differences in sensitivity among individual isolates were recorded in fungicides with the active ingredients azoxystrobin and metiram. In the case of the fungicide with active ingredient azoxystrobin, the highest inhibitory effect was achieved in the safflower isolate and the lowest in the white lupin isolate. After treatment with the fungicide with active ingredient metiram, the lowest germination rate was recorded in isolates from safflower and strawberry and the highest in isolates from hypericum and lupin.

  15. The fungicide triadimefon affects beer flavor and composition by influencing Saccharomyces cerevisiae metabolism

    Science.gov (United States)

    Kong, Zhiqiang; Li, Minmin; An, Jingjing; Chen, Jieying; Bao, Yuming; Francis, Frédéric; Dai, Xiaofeng

    2016-09-01

    Despite the fact that beer is produced on a large scale, the effects of pesticide residues on beer have been rarely investigated. In this study, we used micro-brewing settings to determine the effect of triadimefon on the growth of Saccharomyces cerevisiae and beer flavor. The yeast growth in medium was significantly inhibited (45%) at concentrations higher than 5 mg L-1, reaching 80% and 100% inhibition at 10 mg L-1 and 50 mg L-1, respectively. There were significant differences in sensory quality between beer samples fermented with and without triadimefon based on data obtained with an electronic tongue and nose. Such an effect was most likely underlain by changes in yeast fermentation activity, including decreased utilization of maltotriose and most amino acids, reduced production of isobutyl and isoamyl alcohols, and increased ethyl acetate content in the fungicide treated samples. Furthermore, yeast metabolic profiling by phenotype microarray and UPLC/TOF-MS showed that triadimefon caused significant changes in the metabolism of glutathione, phenylalanine and sphingolipids, and in sterol biosynthesis. Thus, triadimefon negatively affects beer sensory qualities by influencing the metabolic activity of S. cerevisiae during fermentation, emphasizing the necessity of stricter control over fungicide residues in brewing by the food industry.

  16. Effects of drugs inhibiting prostaglandin or leukotriene biosynthesis on postirradiation haematopoiesis in mouse

    Energy Technology Data Exchange (ETDEWEB)

    Kozubik, A.; Hofmanova, J.; Pospisil, M.; Netikova, J.; Hola, J.; Lojek, A. (Ceskoslovenska Akademie Ved, Brno (Czech Republic). Biofysikalni Ustav)

    1994-03-01

    Two non-steroidal anti-inflammatory drugs, i.e. indomethacin (INDO), an inhibitor of prostaglandin production, and esculetin (ESCUL), an inhibitor of leukotriene production, were tested for their ability to modify haematopoiesis in three experimental systems: (a) in vitro clonal proliferation of marrow GM-CFC from the irradiated mouse was found to be augmented by addition of INDO at a low concentration, and inhibited by ESCUL in a dose-dependent manner; (b) in the lethally irradiated and bone marrow-transplanted mice treated with the drugs in the postirradiation period, stimulatory effects of INDO on CFU-S and GM-CFC populations and an inhibitory effect of ESCUL on GM-CFC were observed; and (c) when the drugs were administered i.p. to mice 1 h before 5-Gy irradiation, INDO enhanced the postirradiation recovery of haematopoietic indices such the numbers of CFU-S, GM-CFC, peripheral blood granuloctyes, and nucleated bone marrow cells, while ESCUL had no effect or even inhibited the recovery of these indices. (author).

  17. Environmental DNA-encoded antibiotics fasamycins A and B inhibit FabF in type II fatty acid biosynthesis.

    Science.gov (United States)

    Feng, Zhiyang; Chakraborty, Debjani; Dewell, Scott B; Reddy, Boojala Vijay B; Brady, Sean F

    2012-02-15

    In a recent study of polyketide biosynthetic gene clusters cloned directly from soil, we isolated two antibiotics, fasamycins A and B, which showed activity against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecalis. To identify the target of the fasamycins, mutants with elevated fasamycin A minimum inhibitory concentrations were selected from a wild-type culture of E. faecalis OG1RF. Next-generation sequencing of these mutants, in conjunction with in vitro biochemical assays, showed that the fasamycins inhibit FabF of type II fatty acid biosynthesis (FASII). Candidate gene overexpression studies also showed that fasamycin resistance is conferred by fabF overexpression. On the basis of comparisons with known FASII inhibitors and in silico docking studies, the chloro-gem-dimethyl-anthracenone substructure seen in the fasamycins is predicted to represent a naturally occurring FabF-specific antibiotic pharmacophore. Optimization of this pharmacophore should yield FabF-specific antibiotics with increased potencies and differing spectra of activity. This study demonstrates that culture-independent antibiotic discovery methods have the potential to provide access to novel metabolites with modes of action that differ from those of antibiotics currently in clinical use.

  18. Pectocin M1 (PcaM1 Inhibits Escherichia coli Cell Growth and Peptidoglycan Biosynthesis through Periplasmic Expression

    Directory of Open Access Journals (Sweden)

    Dimitri Chérier

    2016-10-01

    Full Text Available Colicins are bacterial toxins produced by some Escherichia coli strains. They exhibit either enzymatic or pore-forming activity towards a very limited number of bacterial species, due to the high specificity of their reception and translocation systems. Yet, we succeeded in making the colicin M homologue from Pectobacterium carotovorum, pectocin M1 (PcaM1, capable of inhibiting E. coli cell growth by bypassing these reception and translocation steps. This goal was achieved through periplasmic expression of this pectocin. Indeed, when appropriately addressed to the periplasm of E. coli, this pectocin could exert its deleterious effects, i.e., the enzymatic degradation of the peptidoglycan lipid II precursor, which resulted in the arrest of the biosynthesis of this essential cell wall polymer, dramatic morphological changes and, ultimately, cell lysis. This result leads to the conclusion that colicin M and its various orthologues constitute powerful antibacterial molecules able to kill any kind of bacterium, once they can reach their lipid II target. They thus have to be seriously considered as promising alternatives to antibiotics.

  19. A rapid in situ procedure for determination of bacterial susceptibility or resistance to antibiotics that inhibit peptidoglycan biosynthesis

    Directory of Open Access Journals (Sweden)

    Bou Germán

    2011-08-01

    Full Text Available Abstract Background Antibiotics which inhibit bacterial peptidoglycan biosynthesis are the most widely used in current clinical practice. Nevertheless, resistant strains increase dramatically, with serious economic impact and effects on public health, and are responsible for thousands of deaths each year. Critical clinical situations should benefit from a rapid procedure to evaluate the sensitivity or resistance to antibiotics that act at the cell wall. We have adapted a kit for rapid determination of bacterial DNA fragmentation, to assess cell wall integrity. Results Cells incubated with the antibiotic were embedded in an agarose microgel on a slide, incubated in an adapted lysis buffer, stained with a DNA fluorochrome, SYBR Gold and observed under fluorescence microscopy. The lysis affects the cells differentially, depending on the integrity of the wall. If the bacterium is susceptible to the antibiotic, the weakened cell wall is affected by the lysing solution so the nucleoid of DNA contained inside the bacterium is released and spread. Alternatively, if the bacterium is resistant to the antibiotic, it is practically unaffected by the lysis solution and does not liberate the nucleoid, retaining its normal morphological appearance. In an initial approach, the procedure accurately discriminates susceptible, intermediate and resistant strains of Escherichia coli to amoxicillin/clavulanic acid. When the bacteria came from an exponentially growing liquid culture, the effect on the cell wall of the β-lactam was evident much earlier that when they came from an agar plate. A dose-response experiment with an E. coli strain susceptible to ampicillin demonstrated a weak effect before the MIC dose. The cell wall damage was not homogenous among the different cells, but the level of damage increased as dose increased with a predominant degree of effect for each dose. A microgranular-fibrilar extracellular background was evident in gram

  20. Substituted Caffeic and Ferulic Acid Phenethyl Esters: Synthesis, Leukotrienes Biosynthesis Inhibition, and Cytotoxic Activity

    Directory of Open Access Journals (Sweden)

    Pier Morin

    2017-07-01

    Full Text Available Glioblastoma multiforme (GBM is an aggressive brain tumor that correlates with short patient survival and for which therapeutic options are limited. Polyphenolic compounds, including caffeic acid phenethyl ester (CAPE, 1a, have been investigated for their anticancer properties in several types of cancer. To further explore these properties in brain cancer cells, a series of caffeic and ferulic acid esters bearing additional oxygens moieties (OH or OCH3 were designed and synthesized. (CAPE, 1a, but not ferulic acid phenethyl ester (FAPE, 1b, displayed substantial cytotoxicity against two glioma cell lines. Some but not all selected compounds derived from both (CAPE, 1a and (FAPE, 1b also displayed cytotoxicity. All CAPE-derived compounds were able to significantly inhibit 5-lipoxygenase (5-LO, however FAPE-derived compounds were largely ineffective 5-LO inhibitors. Molecular docking revealed new hydrogen bonds and π-π interactions between the enzyme and some of the investigated compounds. Overall, this work highlights the relevance of exploring polyphenolic compounds in cancer models and provides additional leads in the development of novel therapeutic strategies in gliomas.

  1. Chemosensitization of plant pathogenic fungi to agricultural fungicides.

    Directory of Open Access Journals (Sweden)

    Vitaly eDzhavakhiya

    2012-03-01

    Full Text Available A common consequence of using agricultural fungicides is the development of resistance by fungal pathogens, which undermines reliability of fungicidal effectiveness. A potentially new strategy to aid in overcoming or minimizing this problem is enhancement of pathogen sensitivity to fungicides, or chemosensitization. Chemosensitization can be accomplished by combining a commercial fungicide with a certain non- or marginally fungicidal substance at levels where, alone, neither compound would be effective. Chemosensitization decreases the probability of the pathogen developing resistance, reduces the toxic impact on the environment by lowering effective dosage levels of toxic fungicides, and improves efficacy of antifungal agents. The present study shows that the antifungal activity of azole and strobilurin fungicides can be significantly enhanced through their co-application with certain natural or synthetic products against several economically important plant pathogenic fungi. Quadris (azoxystrobin combined with thymol at a non-fungitoxic concentration produced much higher growth inhibition of Bipolaris sorokiniana, Phoma glomerata, Alternaria sp. and Stagonospora nodorum than the fungicide alone. The effect of Dividend (difenoconazole applied with thymol significantly enhanced antifungal activity against B. sorokiniana and S. nodorum. Folicur (tebuconazole combined with 4-hydroxybenzaldehyde (4-HBA, 2,3-dihydroxybenzaldehyde or thymol significantly inhibited growth of A. alternata, at a much greater level than the fungicide alone. In addition, co-application of Folicur and 4-HBA resulted in a similar enhancement of antifungal activity against Fusarium culmorum. Lastly, we discovered that metabolites in the culture liquid of F. sambucinum biocontrol isolate FS-94 also had chemosensitizing activity, increasing S. nodorum sensitivity to Folicur and Dividend.

  2. Indaziflam: a new cellulose-biosynthesis-inhibiting herbicide provides long-term control of invasive winter annual grasses.

    Science.gov (United States)

    Sebastian, Derek J; Fleming, Margaret B; Patterson, Eric L; Sebastian, James R; Nissen, Scott J

    2017-10-01

    Indaziflam is a cellulose-biosynthesis-inhibiting (CBI) herbicide that is a unique mode of action for resistance management and has broad spectrum activity at low application rates. This research further explores indaziflam's activity on monocotyledons and dicotyledons and evaluates indaziflam's potential for restoring non-crop sites infested with invasive winter annual grasses. Treated Arabidopsis, downy brome, feral rye and kochia were all susceptible to indaziflam in a dose-dependent manner. We confirmed that indaziflam has increased activity on monocots (average GR 50  = 231 pm and 0.38 g AI ha -1 ) at reduced concentrations compared with dicots (average GR 50  = 512 pm and 0.87 g AI ha -1 ). Fluorescence microscopy confirmed common CBI symptomologies following indaziflam treatments, as well as aberrant root and cell morphology. Across five application timings, indaziflam treatments resulted in superior invasive winter annual grass control 2 years after treatment (from 84 ± 5.1% to 99 ± 0.5%) compared with imazapic (36% ± 1.2%). Indaziflam treatments significantly increased biomass and species richness of co-occurring species 2 years after treatment. Indaziflam's increased activity on monocots could provide a new alternative management strategy for long-term control of multiple invasive winter annual grasses that invade >23 million ha of US rangeland. Indaziflam could potentially be used to eliminate the soil seed bank of these invasive grasses, reduce fine fuel accumulation and ultimately increase the competitiveness of perennial co-occuring species. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  3. The isotridecanyl side chain of plusbacin-A3 is essential for the transglycosylase inhibition of peptidoglycan biosynthesis.

    Science.gov (United States)

    Kim, Sung Joon; Singh, Manmilan; Wohlrab, Aaron; Yu, Tsyr-Yan; Patti, Gary J; O'Connor, Robert D; VanNieuwenhze, Michael; Schaefer, Jacob

    2013-03-19

    Plusbacin-A3 (pb-A3) is a cyclic lipodepsipeptide that exhibits antibacterial activity against multidrug-resistant Gram-positive pathogens. Plusbacin-A3 is thought not to enter the cell cytoplasm, and its lipophilic isotridecanyl side chain is presumed to insert into the membrane bilayer, thereby facilitating either lipid II binding or some form of membrane disruption. Analogues of pb-A3, [(2)H]pb-A3 and deslipo-pb-A3, were synthesized to test membrane insertion as a key to the mode of action. [(2)H]pb-A3 has an isotopically (2)H-labeled isopropyl subunit of the lipid side chain, and deslipo-pb-A3 is missing the isotridecanyl side chain. Both analogues have the pb-A3 core structure. The loss of antimicrobial activity in deslipo-pb-A3 showed that the isotridecanyl side chain is crucial for the mode of action of the drug. However, rotational-echo double-resonance nuclear magnetic resonance characterization of [(2)H]pb-A3 bound to [1-(13)C]glycine-labeled whole cells of Staphylococcus aureus showed that the isotridecanyl side chain does not insert into the lipid membrane but instead is found in the staphylococcal cell wall, positioned near the pentaglycyl cross-bridge of the cell-wall peptidoglycan. Addition of [(2)H]pb-A3 during the growth of S. aureus resulted in the accumulation of Park's nucleotide, consistent with the inhibition of the transglycosylation step of peptidoglycan biosynthesis.

  4. Inhibition of Lipid A Biosynthesis as the Primary Mechanism of CHIR-090 Antibiotic Activity in Escherichia coli

    Science.gov (United States)

    Barb, Adam W.; McClerren, Amanda L.; Snehelatha, Karnem; Reynolds, C. Michael; Zhou, Pei; Raetz, Christian R.H.

    2009-01-01

    The deacetylation of UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine (UDP-3-O-acyl-GlcNAc) by LpxC is the committed reaction of lipid A biosynthesis. CHIR-090, a novel N-aroyl-l-threonine hydroxamic acid, is a potent, slow, tight-binding inhibitor of the LpxC deacetylase from the hyperthermophile Aquifex aeolicus, and it has excellent antibiotic activity against P. aeruginosa and E. coli, as judged by disk diffusion assays. We now report that CHIR-090 is also a two-step slow, tight-binding inhibitor of Escherichia coli LpxC with Ki = 4.0 nM, Ki* = 0.5 nM, k5 = 1.9 min-1 and k6 = 0.18 min-1. CHIR-090 at low nM levels inhibits LpxC orthologues from diverse Gram-negative pathogens, including Pseudomonas aeruginosa, Neisseria meningitidis, and Helicobacter pylori. In contrast, CHIR-090 is a relatively weak competitive and conventional inhibitor (lacking slow, tight-binding kinetics) of LpxC from Rhizobium leguminosarum (Ki = 340 nM), a Gram-negative plant endosymbiont that is resistant to this compound. The KM (4.8 μM) and the kcat (1.7 s-1) of R. leguminosarum LpxC with UDP-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine as the substrate are similar to values reported for E. coli LpxC. R. leguminosarum LpxC therefore provides a useful control for validating LpxC as the primary target of CHIR-090 in vivo. An E. coli construct in which the chromosomal lpxC gene is replaced by R. leguminosarum lpxC is resistant to CHIR-090 up to 100 μg/mL, or 400 times above the minimal inhibitory concentration for wild-type E. coli. Given its relatively broad spectrum and potency against diverse Gram-negative pathogens, CHIR-090 is an excellent lead for the further development of new antibiotics targeting the lipid A pathway. PMID:17335290

  5. Inhibition of phenylpropanoid biosynthesis increases cell wall digestibility, protoplast isolation, and facilitates sustained cell division in American elm (Ulmus americana).

    Science.gov (United States)

    Jones, A Maxwell P; Chattopadhyay, Abhishek; Shukla, Mukund; Zoń, Jerzy; Saxena, Praveen K

    2012-05-30

    Protoplast technologies offer unique opportunities for fundamental research and to develop novel germplasm through somatic hybridization, organelle transfer, protoclonal variation, and direct insertion of DNA. Applying protoplast technologies to develop Dutch elm disease resistant American elms (Ulmus americana L.) was proposed over 30 years ago, but has not been achieved. A primary factor restricting protoplast technology to American elm is the resistance of the cell walls to enzymatic degradation and a long lag phase prior to cell wall re-synthesis and cell division. This study suggests that resistance to enzymatic degradation in American elm was due to water soluble phenylpropanoids. Incubating tobacco (Nicotiana tabacum L.) leaf tissue, an easily digestible species, in aqueous elm extract inhibits cell wall digestion in a dose dependent manner. This can be mimicked by p-coumaric or ferulic acid, phenylpropanoids known to re-enforce cell walls. Culturing American elm tissue in the presence of 2-aminoindane-2-phosphonic acid (AIP; 10-150 μM), an inhibitor of phenylalanine ammonia lyase (PAL), reduced flavonoid content, decreased tissue browning, and increased isolation rates significantly from 11.8% (±3.27) in controls to 65.3% (±4.60). Protoplasts isolated from callus grown in 100 μM AIP developed cell walls by day 2, had a division rate of 28.5% (±3.59) by day 6, and proliferated into callus by day 14. Heterokaryons were successfully produced using electrofusion and fused protoplasts remained viable when embedded in agarose. This study describes a novel approach of modifying phenylpropanoid biosynthesis to facilitate efficient protoplast isolation which has historically been problematic for American elm. This isolation system has facilitated recovery of viable protoplasts capable of rapid cell wall re-synthesis and sustained cell division to form callus. Further, isolated protoplasts survived electrofusion and viable heterokaryons were produced. Together

  6. Inhibition of serine palmitoyltransferase in vitro and long-chain base biosynthesis in intact Chinese hamster ovary cells by β-chloroalanine

    International Nuclear Information System (INIS)

    Medlock, K.A.; Merrill, A.H. Jr.

    1988-01-01

    The effects of β-chloroalanine (β-Cl-alanine) on the serine palmitoyltransferase activity and the de novo biosynthesis of sphinganine and sphingenine were investigated in vitro with rat liver microsomes and in vivo with intact Chinese hamster ovary (CHO) cells. The inhibition in vitro was rapid, irreversible, and concentration and time dependent and apparently involved the active site because inactivation only occurred with β-Cl-L-alanine and was blocked by L-serine. These are characteristics of mechanism-based (suicide) inhibition. Serine palmitoyltransferase (SPT) was also inhibited when intact CHO cells were incubated with β-Cl-alanine and this treatment inhibited [ 14 C]serine incorporation into long-chain bases by intact cells. The concentration dependence of the loss of SPT activity and of long-chain base synthesis was identical. The effects of β-Cl-alanine appeared to occur with little perturbation of other cell functions: the cells exhibited no loss in cell viability, [ 14 C]serine uptake was not blocked, total lipid biosynthesis from [ 14 C]acetic acid was not decreased (nor was the appearance of radiolabel in cholesterol and phosphatidylcholine), and [ 3 H]thymidine incorporation into DNA was not affected. There appeared to be little effect on protein synthesis based on the incorporation of [ 3 H]leucine, which was only decreased by 14%. Although β-Cl-L-alanine is known to inhibit other pyridoxal 5'-phosphate dependent enzymes, alanine and aspartate transaminases were not inhibited under these conditions. These results establish the close association between the activity of serine palmitoyltransferase and the cellular rate of long-chain base formation and indicate that β-Cl-alanine and other mechanism-based inhibitors might be useful to study alterations in cellular long-chain base synthesis

  7. 1,8-dihydroxynaphthalene (DHN)-melanin biosynthesis inhibitors increase erythritol production in Torula corallina, and DHN-melanin inhibits erythrose reductase.

    Science.gov (United States)

    Lee, Jung-Kul; Jung, Hyung-Moo; Kim, Sang-Yong

    2003-06-01

    The yeast Torula corallina is a strong erythritol producer that is used in the industrial production of erythritol. However, melanin accumulation during culture represents a serious problem for the purification of erythritol from the fermentation broth. Melanin biosynthesis inhibitors such as 3,4-dihydroxyphenylalanine and 1,8-dihydroxynaphthalene (DHN)-melanin inhibitors were added to the T. corallina cultures. Only the DHN-melanin inhibitors showed an effect on melanin production, which suggests that the melanin formed during the culturing of T. corallina is derived from DHN. This finding was confirmed by the detection of a shunt product of the pentaketide pathway, flaviolin, and elemental analysis. Among the DHN-melanin inhibitors, tricyclazole was the most effective. Supplementation with tricyclazole enhanced the production of erythritol while significantly inhibiting the production of DHN-melanin and DHN-melanin biosynthetic enzymes, such as trihydroxynaphthalene reductase. The erythrose reductase from T. corallina was purified to homogeneity by ion-exchange and affinity chromatography. Purified erythrose reductase was significantly inhibited in vitro in a noncompetitive manner by elevated levels of DHN-melanin. In contrast, the level of erythrose reductase activity was unaffected by increasing concentrations of tricyclazole. These results suggest that supplemental tricyclazole reduces the production of DHN-melanin, which may lead to a reduction in the inhibition of erythrose reductase and a higher yield of erythritol. This is the first report to demonstrate that melanin biosynthesis inhibitors increase the production of a sugar alcohol in T. corallina.

  8. Role of sterol 3-ketoreductase sensitivity in susceptibility to the fungicide fenhexamid in Botrytis cinerea and other phytopathogenic fungi.

    Science.gov (United States)

    Debieu, Danièle; Bach, Jocelyne; Montesinos, Emeline; Fillinger, Sabine; Leroux, Pierre

    2013-05-01

    The narrow-spectrum fungicide fenhexamid was introduced into French vineyards in 2000 to control grey mould caused by a complex of two cryptic species: Botrytis cinerea, the predominant species sensitive to fenhexamid, and Botrytis pseudocinerea, naturally resistant. Fenhexamid was suggested to inhibit the 3-ketoreductase involved at C-4 demethylation steps during ergosterol biosynthesis, as revealed by its effects on the B. cinerea sterol profile. Resistance monitoring studies have hitherto identified two B. cinerea fenhexamid-resistant phenotypes, both resulting from mutations in the erg27 gene encoding 3-ketoreductase. The role of 3-ketoreductase sensitivity in fungal susceptibility to fenhexamid was investigated by studying sterol profiles and microsomal 3-ketoreductase in various fungal strains. Fenhexamid does inhibit B. cinerea 3-ketoreductase activity. Erg27 mutations causing amino acid substitutions in or near the transmembrane domain strongly decrease the affinity of fenhexamid for 3-ketoreductase. Fenhexamid has very low affinities for 3-ketoreductase in inherently resistant species, whether closely related to B. cinerea, like B. pseudocinerea, or more distantly related, like Nectria haematococca. erg27 mutation and erg27 polymorphism may therefore contribute to the unfavourable binding of fenhexamid to its target, 3-ketoreductase, explaining the acquisition of fenhexamid resistance in B. cinerea and the narrow spectrum of this fungicide. © 2012 Society of Chemical Industry.

  9. Impact of Chemical Analogs of 4-Hydroxybenzoic Acid on Coenzyme Q Biosynthesis: From Inhibition to Bypass of Coenzyme Q Deficiency

    Directory of Open Access Journals (Sweden)

    Fabien Pierrel

    2017-06-01

    Full Text Available Coenzyme Q is a lipid that participates to important physiological functions. Coenzyme Q is synthesized in multiple steps from the precursor 4-hydroxybenzoic acid. Mutations in enzymes that participate to coenzyme Q biosynthesis result in primary coenzyme Q deficiency, a type of mitochondrial disease. Coenzyme Q10 supplementation of patients is the classical treatment but it shows limited efficacy in some cases. The molecular understanding of the coenzyme Q biosynthetic pathway allowed the design of experiments to bypass deficient biosynthetic steps with analogs of 4-hydroxybenzoic acid. These molecules provide the defective chemical group and can reactivate endogenous coenzyme Q biosynthesis as demonstrated recently in yeast, mammalian cell cultures, and mouse models of primary coenzyme Q deficiency. This mini review presents how the chemical properties of various analogs of 4-hydroxybenzoic acid dictate the effect of the molecules on CoQ biosynthesis and how the reactivation of endogenous coenzyme Q biosynthesis may achieve better results than exogenous CoQ10 supplementation.

  10. Salvianolic Acid A Inhibits PDGF-BB Induced Vascular Smooth Muscle Cell Migration and Proliferation While Does Not Constrain Endothelial Cell Proliferation and Nitric Oxide Biosynthesis

    Directory of Open Access Journals (Sweden)

    Chao Huang

    2012-03-01

    Full Text Available Proliferation and migration of vascular smooth muscle cells (VSMCs are critical events in the initiation and development of restenosis upon percutaneous transluminal coronary angioplasty (PTCA. Polyphenols have been suggested to ameliorate post-angioplasty restenosis. Salvianolic A (SalA is one of the most abundant polyphenols extracted from salvia. In this study, we investigated the effect of salvianolic A (SalA on the migration and proliferation of VSMCs. We found a preferential interaction of SalA with cellular systems that rely on the PDGF signal, but not on the EGF and bFGF signal. SalA inhibits PDGF-BB induced VSMC proliferation and migration in the concentration range from 0.01 to 0.1 μM. The inhibition of SalA on VSMC proliferation is associated with cell cycle arrest. We also found that SalA inhibits the PDGFRβ-ERK1/2 signaling cascade activated by PDGF-BB in VSMCs. In addition, SalA does not influence the proliferation of endothelial cells, the synthesis of NO and eNOS protein expression. Our results suggest that SalA inhibits migration and proliferation of VSMCs induced by PDGF-BB via the inhibition of the PDGFRβ-ERK1/2 cascade, but that it does not constrain endothelial cell proliferation and nitric oxide biosynthesis. Thus, the present study suggests a novel adjunct pharmacological strategy to prevent angioplasty-related restenosis.

  11. Flavan-3-ols isolated from some medicinal plants inhibiting COX-1 and COX-2 catalysed prostaglandin biosynthesis.

    Science.gov (United States)

    Noreen, Y; Serrano, G; Perera, P; Bohlin, L

    1998-08-01

    Extracts from the four plant species Atuna racemosa Raf. ssp. racemosa, Syzygium corynocarpum (A. Gray) C. Muell., Syzygium malaccense (L.) Merr. & Perry and Vantanea peruviana Macbr., traditionally used for inflammatory conditions, were fractionated using a cyclooxygenase-1 catalysed prostaglandin biosynthesis in vitro assay. The flavan-3-ol derivatives (+)-catechin, (+)-gallocatechin, 4'-O-Me-ent-gallocatechin, ouratea-catechin and ouratea-proanthocynidin A were isolated as active principles. The IC50 values ranged from 3.3 microM to 138 microM whilst indomethacin under the same test conditions had an IC50 value of 1.1 microM. The flavonol rhamnosides mearnsitrin, myricitrin and quercitrin were also isolated. When further tested for inhibitory effect on cyclooxygenase-2 catalysed prostaglandin biosynthesis, the five flavan-3-ol derivatives exhibited from equal to weaker inhibitory potencies, as compared to their cyclooxygenase-1 inhibitory effects. The flavonol rhamnosides were inactive towards both enzymes.

  12. Analysis of sublethal arsenic toxicity to Ceratophyllum demersum: subcellular distribution of arsenic and inhibition of chlorophyll biosynthesis

    Czech Academy of Sciences Publication Activity Database

    Mishra, S.; Alfred, M.; Sobotka, Roman; Andresen, E.; Falkenberg, G.; Küpper, Hendrik

    2016-01-01

    Roč. 67, č. 15 (2016), s. 4639-4646 ISSN 0022-0957 R&D Projects: GA ČR GBP501/12/G055; GA MŠk(CZ) LO1416 Institutional support: RVO:61388971 ; RVO:60077344 Keywords : arsenic toxicity * chlorophyll biosynthesis * subcellular distribution of arsenic * synchrotron micro-X-ray fluorescence Subject RIV: EE - Microbiology, Virology; CE - Biochemistry (BC-A) Impact factor: 5.830, year: 2016

  13. Loss of ferulate 5-hydroxylase leads to Mediator-dependent inhibition of soluble phenylpropanoid biosynthesis in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Nickolas; Bonawitz, Nicholas D.; Nyffeler, Kayleigh E.; Chapple, Clint

    2015-06-05

    Phenylpropanoids are phenylalanine-derived specialized metabolites and include important structural components of plant cell walls, such as lignin and hydroxycinnamic acids, as well as ultraviolet and visible light-absorbing pigments, such as hydroxycinnamate esters (HCEs) and anthocyanins. Previous work has revealed a remarkable degree of plasticity in HCE biosynthesis, such that most Arabidopsis (Arabidopsis thaliana) mutants with blockages in the pathway simply redirect carbon flux to atypical HCEs. In contrast, the ferulic acid hydroxylase1 (fah1) mutant accumulates greatly reduced levels of HCEs, suggesting that phenylpropanoid biosynthesis may be repressed in response to the loss of FERULATE 5-HYDROXYLASE (F5H) activity. Here, we show that in fah1 mutant plants, the activity of HCE biosynthetic enzymes is not limiting for HCE accumulation, nor is phenylpropanoid flux diverted to the synthesis of cell wall components or flavonol glycosides. We further show that anthocyanin accumulation is also repressed in fah1 mutants and that this repression is specific to tissues in which F5H is normally expressed. Finally, we show that repression of both HCE and anthocyanin biosynthesis in fah1 mutants is dependent on the MED5a/5b subunits of the transcriptional coregulatory complex Mediator, which are similarly required for the repression of lignin biosynthesis and the stunted growth of the phenylpropanoid pathway mutant reduced epidermal fluorescence8. Taken together, these observations show that the synthesis of HCEs and anthocyanins is actively repressed in a MEDIATOR-dependent manner in Arabidopsis fah1 mutants and support an emerging model in which MED5a/5b act as central players in the homeostatic repression of phenylpropanoid metabolism.

  14. Development and persistence of resistance to fungicides in Sphaerotheca fuliginea in cucumbers in the Netherlands

    NARCIS (Netherlands)

    Schepers, H.T.A.M.

    1985-01-01

    Ergosterol biosynthesis inhibitors (EBIs) have a remarkably broad spectrum of antifungal activity. They belong to the commercial fungicides which exhibit the highest activity known to date. Resistance to EBIs was found in vitro, but the level of resistance and the decreased fitness of resistant

  15. Evaluation of two organosynthetic fungicides, for the control of ...

    African Journals Online (AJOL)

    ... of Pisum stativum L. Results indicated that the two fungicides inhibited Ersiphe polygoni DC. Conidia germination and diseases index to various degrees in vitro, depending on the concentration applied. Results showed an increase in yield of treated seeds as compared to control. Plant Products Research Journal Vol.

  16. The toxicity of the fungicide Propiconazole to soil flagellates

    DEFF Research Database (Denmark)

    Ekelund, Flemming; Westergaard, Kamma; Søe, Dorthe

    2000-01-01

    We investigated the effects of the ergosterol-inhibiting fungicide, propiconazole {1-[[2-(2,4-dichlorphenyl) - 4 - propyl - 1,3 - dioxolan - 2 - yl]methyl] - 1H - 1,2,4 triazole; Tilt}, on mixed natural populations of bacterivorous and fungivorous flagellates in soil and on single species...... of bacterivorous flagellates in liquid culture. The fungicide affected a mixed natural population of fungivorous flagellates less than the population of bacterivorous flagellates. Our results indicated that the effects of propiconazole on flagellates are direct toxic effects and not effects mediated via their food...

  17. Simvastatin inhibits Candida albicans biofilm in vitro.

    Science.gov (United States)

    Liu, Geoffrey; Vellucci, Vincent F; Kyc, Stephanie; Hostetter, Margaret K

    2009-12-01

    By inhibiting the conversion of 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) to mevalonate, statins impair cholesterol metabolism in humans. We reasoned that statins might similarly interfere with the biosynthesis of ergosterol, the major sterol of the yeast cell membrane. As assessed by spectrophotometric and microscopic analysis, significant inhibition of biofilm production was noted after 16-h incubation with 1, 2.5, and 5 muM simvastatin, concentrations that did not affect growth, adhesion, or hyphal formation by C. albicans in vitro. Higher concentrations (10, 20, and 25 muM simvastatin) inhibited biofilm by >90% but also impaired growth. Addition of exogenous ergosterol (90 muM) overcame the effects of 1 and 2.5 muM simvastatin, suggesting that at least one mechanism of inhibition is interference with ergosterol biosynthesis. Clinical isolates from blood, skin, and mucosal surfaces produced biofilms; biofilms from bloodstream isolates were similarly inhibited by simvastatin. In the absence of fungicidal activity, simvastatin's interruption of a critical step in an essential metabolic pathway, highly conserved from yeast to man, has unexpected effects on biofilm production by a eukaryotic pathogen.

  18. Evaluation of fungicides for the control of Botryosphaeria protearum on Protea magnifica in the Western Cape Province of South Africa

    NARCIS (Netherlands)

    Denman, S.; Crous, P.W.; Sadie, A.; Wingfield, M.J.

    2004-01-01

    A range of fungicides was tested in vitro for their effect on mycelial inhibition. Selected products showing potential for disease control were then further tested under field conditions. The most effective fungicides in the in vitro tests were tebuconazole, benomyl, prochloraz me, iprodione and

  19. A Saccharomyces cerevisiae Wine Strain Inhibits Growth and Decreases Ochratoxin A Biosynthesis by Aspergillus carbonarius and Aspergillus ochraceus

    Directory of Open Access Journals (Sweden)

    Marilena Budroni

    2012-12-01

    Full Text Available The aim of this study was to select wine yeast strains as biocontrol agents against fungal contaminants responsible for the accumulation of ochratoxin A (OTA in grape and wine and to dissect the mechanism of OTA detoxification by a Saccharomyces cerevisiae strain (DISAABA1182, which had previously been reported to reduce OTA in a synthetic must. All of the yeast strains tested displayed an ability to inhibit the growth of Aspergillus carbonarius both in vivo and in vitro and addition of culture filtrates from the tested isolates led to complete inhibition of OTA production. S. cerevisiae DISAABA1182 was selected and further tested for its capacity to inhibit OTA production and pks (polyketide synthase transcription in A. carbonarius and Aspergillus ochraceus in vitro. In order to dissect the mechanism of OTA detoxification, each of these two fungi was co-cultured with living yeast cells exposed to yeast crude or to autoclaved supernatant: S. cerevisiae DISAABA1182 was found to inhibit mycelial growth and OTA production in both Aspergilli when co-cultured in the OTA-inducing YES medium. Moreover, a decrease in pks transcription was observed in the presence of living cells of S. cerevisiae DISAABA1182 or its supernatant, while no effects were observed on transcription of either of the constitutively expressed calmodulin and β-tubulin genes. This suggests that transcriptional regulation of OTA biosynthetic genes takes place during the interaction between DISAABA1182 and OTA-producing Aspergilli.

  20. Triazole fungicide tebuconazole disrupts human placental trophoblast cell functions

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jinghua [Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, Zhejiang University, Hangzhou 310058 (China); Zhang, Jianyun [Research Center for Air Pollution and Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Li, Feixue [Zhejiang Key Laboratory of Organ Development and Regeneration, Institute of Developmental and Regenerative Biology, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036 (China); Liu, Jing, E-mail: jliue@zju.edu.cn [Key Laboratory of Environmental Remediation and Ecological Health, Ministry of Education, Zhejiang University, Hangzhou 310058 (China); Research Center for Air Pollution and Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China)

    2016-05-05

    Highlights: • Tebuconazole (TEB) inhibited the proliferation of human placental trophoblasts. • TEB changed cell cycle distribution of G1 and G2 phases of trophoblasts. • TEB induced apoptosis of trophoblasts via mitochondrial pathway. • TEB decreased the invasive and migratory capacities of trophoblasts. • TEB altered the mRNA levels of key regulatory genes in trophoblasts - Abstract: Triazole fungicides are one of the top ten classes of current-use pesticides. Although exposure to triazole fungicides is associated with reproductive toxicity in mammals, limited information is available regarding the effects of triazole fungicides on human placental trophoblast function. Tebuconazole (TEB) is a common triazole fungicide that has been extensively used for fungi control. In this work, we showed that TEB could reduce cell viability, disturb normal cell cycle distribution and induce apoptosis of human placental trophoblast cell line HTR-8/SVneo (HTR-8). Bcl-2 protein expression decreased and the level of Bax protein increased after TEB treatment in HTR-8 cells. The results demonstrated that this fungicide induced apoptosis of trophoblast cells via mitochondrial pathway. Importantly, we found that the invasive and migratory capacities of HTR-8 cells decreased significantly after TEB administration. TEB altered the expression of key regulatory genes involved in the modulation of trophoblast functions. Taken together, TEB suppressed human trophoblast invasion and migration through affecting the expression of protease, hormones, angiogenic factors, growth factors and cytokines. As the invasive and migratory abilities of trophoblast are essential for successful placentation and fetus development, our findings suggest a potential risk of triazole fungicides to human pregnancy.

  1. Triazole fungicide tebuconazole disrupts human placental trophoblast cell functions

    International Nuclear Information System (INIS)

    Zhou, Jinghua; Zhang, Jianyun; Li, Feixue; Liu, Jing

    2016-01-01

    Highlights: • Tebuconazole (TEB) inhibited the proliferation of human placental trophoblasts. • TEB changed cell cycle distribution of G1 and G2 phases of trophoblasts. • TEB induced apoptosis of trophoblasts via mitochondrial pathway. • TEB decreased the invasive and migratory capacities of trophoblasts. • TEB altered the mRNA levels of key regulatory genes in trophoblasts - Abstract: Triazole fungicides are one of the top ten classes of current-use pesticides. Although exposure to triazole fungicides is associated with reproductive toxicity in mammals, limited information is available regarding the effects of triazole fungicides on human placental trophoblast function. Tebuconazole (TEB) is a common triazole fungicide that has been extensively used for fungi control. In this work, we showed that TEB could reduce cell viability, disturb normal cell cycle distribution and induce apoptosis of human placental trophoblast cell line HTR-8/SVneo (HTR-8). Bcl-2 protein expression decreased and the level of Bax protein increased after TEB treatment in HTR-8 cells. The results demonstrated that this fungicide induced apoptosis of trophoblast cells via mitochondrial pathway. Importantly, we found that the invasive and migratory capacities of HTR-8 cells decreased significantly after TEB administration. TEB altered the expression of key regulatory genes involved in the modulation of trophoblast functions. Taken together, TEB suppressed human trophoblast invasion and migration through affecting the expression of protease, hormones, angiogenic factors, growth factors and cytokines. As the invasive and migratory abilities of trophoblast are essential for successful placentation and fetus development, our findings suggest a potential risk of triazole fungicides to human pregnancy.

  2. Control of sugar beet powdery mildew with strobilurin fungicides

    Directory of Open Access Journals (Sweden)

    Karaoglanidis George S.

    2006-01-01

    Full Text Available Powdery mildew, caused by Erysiphe betae is a major foliar disease of sugar beet in areas with dry and relatively warm weather conditions throughout the world. In the present study, four fungicides belonging to the relatively new class of strobilurin fungicides, azoxystrobin, kresoxim-methyl pyraclostrobin and trifloxystrobin were evaluated in three different application doses (100, 150 and 200 mg a.i. ha–1 during 2003-2004 for the control of the disease. Among the four strobilurin fungicides tested trifloxystrobin and kresoxim-methyl were the most effective with control efficiency values higher than 94% compared to the control treatment even when applied at lower application dose of 100 mg a.i. ha–1. Azoxystrobin and pyraclostrobin showed a poor to modest activity against the disease even when applied at the highest application dose of 200 μg a.i. ha–1. Disease severity, in terms of AUDPC values was significantly correlated to decreased root yield, while no significant correlation existed among disease severity and sugar content of the roots or sucrose yield. In addition, the efficiency of tank mixtures of four strobilurin fungicides applied at 100 μg a.i. ha–1 with two sterol demethylation - inhibiting fungicides (DMIs, difenoconazole and cyproconazole applied at 62.5 and 25 mg a.i. ha–1, respectively, was evaluated. The mixtures of azoxystrobin and pyraclostrobin with either difenoconazole or cyproconazole provided a better control efficiency compared to the single application of each mixture partner, while the tank mixtures of trifloxystrobin and kresoxim-methyl with either difenoconazole or cyproconazole provided a better control efficiency compared to single application of difenoconazole or cyproconazole and similar control efficiency compared to the efficiency obtained by single application of the strobilurin fungicides.

  3. Population density of Beauveria bassiana in soil under the action of fungicides and native microbial populations

    Directory of Open Access Journals (Sweden)

    Flávia Barbosa Soares

    2017-08-01

    Full Text Available This study investigated whether populations of naturally-occurring soil bacteria, fungi and actinomycetes influence the effect of fungicides on the survival and growth of Beauveria bassiana. The toxicity of methyl thiophanate, pyraclostrobin, mancozeb and copper oxychloride at the recommended doses was analyzed in culture medium and in soil inoculated with fungus at various time points after addition of fungicides. All fungicides completely inhibited the growth and sporulation of B. bassiana in the culture medium. The fungicides were less toxic in soil, emphasizing the action of the microbial populations, which interfered with the toxic effects of these products to the fungus. Actinomycetes had the greatest influence on the entomopathogen, inhibiting it or degrading the fungicides to contribute to the survival and growth of B. bassiana in soil. Native populations of fungi and bacteria had a smaller influence on the population density of B. bassiana and the action of fungicides towards entomopathogen. The toxic effect of the fungicides was greater when added to the soil one hour before or after inoculation than at 48h after inoculation.

  4. Inhibition of In Vitro Leukotriene B-4 Biosynthesis in Human Neutrophil Granulocytes and Docking Studies of Natural Quinones

    Czech Academy of Sciences Publication Activity Database

    Landa, Přemysl; Kutil, Zsófia; Temml, V.; Malík, J.; Kokoška, L.; Widowitz, U.; Přibylová, Marie; Dvořáková, Marcela; Maršík, Petr; Schuster, D.; Bauer, R.; Vaněk, Tomáš

    2013-01-01

    Roč. 8, č. 1 (2013), s. 105-108 ISSN 1934-578X R&D Projects: GA ČR GP525/09/P528; GA MŠk(CZ) MEB061112 Institutional research plan: CEZ:AV0Z50380511 Keywords : 5-Lipoxygenase * Anti-inflammatory activity * Dual COX/LOX inhibition Subject RIV: GM - Food Processing Impact factor: 0.924, year: 2013

  5. A novel bioactive chalcone of Morus australis inhibits tyrosinase activity and melanin biosynthesis in B16 melanoma cells.

    Science.gov (United States)

    Takahashi, Makoto; Takara, Kensaku; Toyozato, Tomonao; Wada, Koji

    2012-01-01

    The methanol extract of Morus australis (shimaguwa) acts as a whitening agent due to the inhibition of tyrosinase activity. In order to explore the mechanism(s) of the whitening action, constituents of the 95% methanol extract from the dried stems of shimaguwa were isolated and their skin-whitening capacity was examined. Bioassay-guided fractionation of the methanol soluble extract of shimaguwa led to the isolation of 2, 4, 2', 4'-hydroxycalcone (chalcone 1) and three analogues of chalcone 1 with 3'-substituted resorcinol moieties (chalcones 2-4). Chalcone derivative 4 proved to be a novel compound and was fully characterized. Chalcones 1-4 were evaluated for inhibition activity on mushroom tyrosinase using L-tyrosine as the substrate. The parent chalcone 1 was a highly effective inhibitor of tyrosinase activity (IC₅₀ = 0.21 μM) compared to arbutin (IC₅₀ = 164 μM). Compared to chalcone 1, chalcones 2 and 3, which possess 3'-substituted isoprenyl or bulky 2-benzoylbiphenyl, showed significantly decreased tyrosinase activity, while chalcone 4, possessing 3'-substituted 2-hydroxy-1-pentene group, showed slightly increased activity.The effects of chalcones 1-4 on melanin synthesis, without affecting cell growth, were assayed in melanin-producing B16 murine melanoma cells. Chalcone 3 significantly reduced cell viability before reaching the IC₅₀ value for melanin synthesis. In contrast, the inhibitory effects of chalcones 1, 2 and 4 were more than 100-fold greater than that of arbutin, with little or no cytotoxicity. More significantly, chalcone 2, which exhibited less tyrosinase inhibitory activity compared to the parent chalcone 1, showed the highest inhibition of melanin synthesis in B16 cells among the chalcones tested. Accordingly, chalcones 1 and 2, and the novel chalcone 4 might be the active components responsible for the whitening ability of shimaguwa. Moreover, whitening ability was not exclusively due to tyrosinase inhibition.

  6. Reduced Fungicide Dose in Cereals

    DEFF Research Database (Denmark)

    Jørgensen, Lise Nistrup; Ørum, Jens Erik

    2017-01-01

    Often the fungicide rates that European farmers apply are lower than the labelled rates. The use of ‘adjusted appropriate rates’ is mainly driven by results from field trials showing sufficient control and better net yield responses compared to full rates. The optimal rate depends on several fact...

  7. Reduced fungicide dose in cereals

    DEFF Research Database (Denmark)

    Jørgensen, Lise Nistrup; Ørum, Jens Erik

    2017-01-01

    Often the fungicide rates that European farmers apply are lower than the labelled rates. The use of ‘adjusted appropriate rates’ is mainly driven by results from field trials showing sufficient control and better net yield responses compared to full rates. The optimal rate depends on several fact...

  8. Platelet Activating Factor (PAF) biosynthesis is inhibited by phenolic compounds in U-937 cells under inflammatory conditions.

    Science.gov (United States)

    Vlachogianni, Ioanna C; Fragopoulou, Elizabeth; Stamatakis, George M; Kostakis, Ioannis K; Antonopoulou, Smaragdi

    2015-09-01

    Interleukin 1 beta (IL-1β) induced platelet activating factor (PAF) synthesis in U-937 cells through stimulation of acetyl-CoA:lysoPAF-acetyltransferase (lyso PAF-AT) at 3 h and DTT-independentCDP-choline-1-alkyl-2-acetyl-sn-glycerol cholinophosphotransferase (PAF-CPT) at 0.5 h. The aim of this study was to investigate the effect of tyrosol (T), resveratrol (R) and their acetylated derivatives(AcDs) which exhibit enhanced bioavailability, on PAF synthesis in U-937 after IL-1β stimulation. The specific activity of PAF enzymes and intracellular levels were measured in cell homogenates. T and R concentration capable of inducing 50% inhibition in IL-1β effect on lyso PAF-AT was 48 μΜ ± 11 and 157 μΜ ± 77, for PAF-CPT 246 μΜ ± 61 and 294 μΜ ± 102, respectively. The same order of concentration was also observed on inhibiting PAF levels produced by IL-1β. T was more potent inhibitor than R (p<0.05). AcDs of T retain parent compound inhibitory activity, while in the case of R only two AcDs retain the activity. The observed inhibitory effect by T,R and their AcDs, may partly explain their already reported beneficial role. Copyright © 2015. Published by Elsevier Inc.

  9. Biosynthesis of silver nanoparticles usingArtemisia annuacallus for inhibiting stem-end bacteria in cut carnation flowers.

    Science.gov (United States)

    Xia, Qian Hua; Zheng, Li Ping; Zhao, Pei Fei; Wang, Jian Wen

    2017-03-01

    A biological method for synthesising silver nanoparticles (AgNPs) was developed using the callus extracts from Artemisia annua L. under sunlight at 25,000 lx. The AgNPs were characterised using transmission electron microscopy, atomic force microscope, X-ray diffraction and Fourier transform infrared spectroscopy. The AgNPs were mostly spherical with the size of 2.1 to 45.2 nm (average 10.9 nm). Pulse treatments of AgNPs at 125, 250 and 500 mg/l for 1 h extended vase life of cut carnation ( Dianthus caryophyllus cv. Green Land) flowers. Four dominant bacteria strains Arthrobacter arilaitensis, Kocuria sp., Staphylococcus equorum and Microbacterium oxydans were isolated from the stem-ends of cut D. caryophyllus flowers. AgNP pulse inhibited significantly bacterial growth in vase solution and cut stem ends during all of the vase period. The bacteria related blockage in the stem-ends was significantly alleviated by AgNP pulse because of its higher antibacterial efficacy against the dominant bacteria. In addition, ethylene release of cut carnation flowers was inhibited in response to AgNP pulse. This is the first time that the biologically synthesised AgNPs could be applied as a promising preservative agent for cut carnation flowers.

  10. Fungicidal activity of silver nanoparticles against Alternaria brassicicola

    Science.gov (United States)

    Gupta, Deepika; Chauhan, Pratima

    2016-04-01

    This work highlighted the fungicidal properties of silver nanoparticles against Alternaria brassicicola. Alternaria brassicicola causes Black spot of Cauliflower, radish, cabbage, kale which results in sever agricultural loss. We treat the synthesised silver nanoparticles (AgNPs) of 10, 25, 50, 100 and 110 ppm concentrations against Alternaria brassicicola on PDA containing Petri dish. We calculated inhibitory rate (%) in order to evaluate the antifungal efficacy of silver nanoparticles against pathogens. Treatment with 100ppm AgNPs resulted in maximum inhibition of Alternaria brassicicola i.e.92.2%. 110ppm of AgNPS also shows the same result, therefore 100ppm AgNPs was treated as optimize concentration. AgNPs effectively inhibited the growth of a Alternaria brassicicola, which suggests that AgNPs could be used as fungicide in plant disease management. Further research and development are necessary to translate this technology into plant disease management strategies.

  11. Evaluation of fungicides and biopesticides for the control of fusarium wilt of tomato

    International Nuclear Information System (INIS)

    Akhtar, T.; Iftikhar, Y.

    2017-01-01

    Fusarium wilt is highly destructive soil borne pathogen in tomato. Current study was carried out to evaluate commercially available fungicides and bio-fungicides in-vitro and in-vivo, for their efficacy against Fusarium oxysporum f.sp. lycopersici. Firstly four fungicides were evaluated under laboratory conditions. Three promising fungicides, two biopesticides and Trichoderma harzianum were further applied both in greenhouse and field experiments. During in-vitro studies PDA amended with fungicides with different treatments at the rate 1% almost completely inhibited the growth of Fol with varying degree of success whereas Nativo being the most effective treatment with 98% reduction in growth as compared to control. Nativo significantly reduced the disease incidence (32.75 %) at concentration of 1%. While Poly-beta-hydroxyl-butyric-acid effectively promoted the tomato growth. Maximum reduction in disease (30.14 %) was expressed by Nativo followed by Teagro (25.06 %) under field conditions. Nativo was found to be the most effective fungicide for management of Fol both In vitro and In vivo. Further field evaluations of the fungicides are required. (author)

  12. Sensitivity of Colletotrichum gloeosporioides Isolates from Diseased Avocado Fruits to Selected Fungicides in Kenya

    Directory of Open Access Journals (Sweden)

    Stanley Kirugo Kimaru

    2018-01-01

    Full Text Available Colletotrichum gloeosporioides is a serious postharvest pathogen of avocado fruits worldwide. Kenya lacks any registered fungicides for the management of the disease. Nevertheless, farmers commonly use commercially available fungicides such as Bayleton 25WP (Triadimefon 250 g/Kg, Milraz 76WP (Propineb 70% and Cymoxanil 6%, and Copper oxychloride 500WP for disease management. The efficacy of these fungicides against C. gloeosporioides is not known. The purpose of this study was therefore to test the inhibitory effect of these fungicides against 46 C. gloeosporioides isolates from avocado fruits collected from varieties grown at different agroecological zones in Murang’a County, a popular avocado-growing region in Kenya. Mycelial growth rate and sporulation for each isolate were measured in vitro on PDA plates amended with different concentrations of the fungicides. Plates were arranged in a completely randomized design with three replications per treatment. All fungicides were effective in vitro but there were significant differences in sensitivity among isolates. Bayleton had the highest mycelial inhibition followed by Milraz, while copper oxychloride had the lowest mycelial inhibition rates, ranging from 81% to 88%. However, copper oxychloride was more effective in inhibiting sporulation. The inhibitory effect of each fungicide was concentration-dependent, where twice the recommended concentration had the highest inhibitory effect, followed by the recommended concentration. Our results show that the fungicides used by farmers against C. gloeosporioides, the causal agent for anthracnose, are effective. We, however, recommend further field tests in different avocado-growing areas so as to validate their efficacy against various isolates and under different environments.

  13. Comparative efficacy of different fungicides against fusarium wilt of chickpea (cicer arietinum l.)

    International Nuclear Information System (INIS)

    Maitlo, S.A.

    2014-01-01

    Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris (Foc) is the most serious and widespread disease of chickpea, causing a 100% loss under favorable conditions. Fourteen fungicides were evaluated against wilt pathogen In vitro with five different concentrations ranging from 1-10000 ppm. Among these only Carbendazim and Thiophanate-methyl was found as the most effective at all used concentrations. Other fungicides like Aliette, Nativo, Hombre-excel and Dividend star were found to be moderately effective. Whereas, remaining fungicides were ineffective against the targeted pathogen. Generally, a positive co-relation was observed between increasing concentrations of the tested fungicides and inhibition of Foc. Based on In vitro results Carbendazim, Thiophanate-methyl, Aliette, Dividend-star, Hombre-excel, Score and Nativo were selected for pot and field experiments. The higher concentrations of the few fungicides completely inhibited the pathogen as well as found to be phytotoxic and suppressed the plant growth while lower concentrations promoted the growth of chickpea plants. On over all bases, the Carbendazim and Thiophanate-methyl, followed by Aliette and Nativo were more effective in reducing the impact of pathogen as well as enhancing the plant growth in greenhouse experiment. Under field conditions, all fungicides except Score remarkably decreased the disease development and subsequently increased the plant growth as well as grain yield as compared to untreated plants. (author)

  14. Esterase isozymes patterns of grape vine (Vitis vinifera L. are altered in response to fungicide exposure

    Directory of Open Access Journals (Sweden)

    Gleice Ribeiro Orasmo

    2015-10-01

    Full Text Available Current analysis characterizes the effect of different fungicides often applied for pest control on a-and b-esterase patterns of four economically important table-wine grape cultivars (Italia, Rubi, Benitaka and Brasil of Vitis vinifera. The a- and b-esterase patterns in bud leaves of the cultivars were assessed by native PAGE analysis. Cabrio Top® compound inhibited Est-2, Est-5, Est-6, Est-7, Est-8, Est-9 and Est-10 carboxylesterases, whereas Est-4, Est-11, Est-12, Est-13, Est-14 acetylesterases and Est-16 carboxylesterase were detected as weakly stained bands. Carboxylesterases and acetylesterases were also detected as weakly stained bands when exposed to fungicides Orthocide 500®, Positron Duo® and Folicur PM®. No changes in a- and b-esterase patterns were reported when the vines were exposed to the fungicides Rovral SC®, Kumulus DF®, Curzate M®, Score® or Cuprogarb 500®. The evidence of functional changes in carboxylesterase and acetylesterase levels in current study is a warning to grape producers on the dangers inherent in the indiscriminate use of potent and modern fungicides extensively used in agriculture. The inhibition effect of fungicides on esterase isozyme molecules seems to be independent of the fungicide chemical.

  15. Two natural products, trans-phytol and (22E)-ergosta-6,9,22-triene-3β,5α,8α-triol, inhibit the biosynthesis of estrogen in human ovarian granulosa cells by aromatase (CYP19)

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jiajia [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu (China); Yuan, Yun [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu (China); School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang (China); Lu, Danfeng; Du, Baowen [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu (China); Xiong, Liang; Shi, Jiangong [State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Yang, Lijuan [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu (China); Liu, Wanli [MOE Key Laboratory of Protein Science, School of Life Sciences, Tsinghua University, Beijing 100084 (China); Yuan, Xiaohong [School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang (China); Zhang, Guolin, E-mail: zhanggl@cib.ac.cn [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu (China); Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu (China); Wang, Fei, E-mail: wangfei@cib.ac.cn [Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu (China); Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu (China)

    2014-08-15

    Aromatase is the only enzyme in vertebrates to catalyze the biosynthesis of estrogens. Although inhibitors of aromatase have been developed for the treatment of estrogen-dependent breast cancer, the whole-body inhibition of aromatase causes severe adverse effects. Thus, tissue-selective aromatase inhibitors are important for the treatment of estrogen-dependent cancers. In this study, 63 natural products with diverse structures were examined for their effects on estrogen biosynthesis in human ovarian granulosa-like KGN cells. Two compounds—trans-phytol (SA-20) and (22E)-ergosta-6,9,22-triene-3β,5α,8α-triol (SA-48)—were found to potently inhibit estrogen biosynthesis (IC{sub 50}: 1 μM and 0.5 μM, respectively). Both compounds decreased aromatase mRNA and protein expression levels in KGN cells, but had no effect on the aromatase catalytic activity in aromatase-overexpressing HEK293A cells and recombinant expressed aromatase. The two compounds decreased the expression of aromatase promoter I.3/II. Neither compound affected intracellular cyclic AMP (cAMP) levels, but they inhibited the phosphorylation or protein expression of cAMP response element-binding protein (CREB). The effects of these two compounds on extracellular regulated kinase (ERK), c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinases (MAPKs), and AKT/phosphoinositide 3-kinase (PI3K) pathway were examined. Inhibition of p38 MAPK could be the mechanism underpinning the actions of these compounds. Our results suggests that natural products structurally similar to SA-20 and SA-48 may be a new source of tissue-selective aromatase modulators, and that p38 MAPK is important in the basal control of aromatase in ovarian granulosa cells. SA-20 and SA-48 warrant further investigation as new pharmaceutical tools for the prevention and treatment of estrogen-dependent cancers. - Highlights: • Two natural products inhibited estrogen biosynthesis in human ovarian granulosa cells. • They

  16. Effects of Sublethal Fungicides on Mutation Rates and Genomic Variation in Fungal Plant Pathogen, Sclerotinia sclerotiorum.

    Directory of Open Access Journals (Sweden)

    B Sajeewa Amaradasa

    Full Text Available Pathogen exposure to sublethal doses of fungicides may result in mutations that may represent an important and largely overlooked mechanism of introducing new genetic variation into strictly clonal populations, including acquisition of fungicide resistance. We tested this hypothesis using the clonal plant pathogen, Sclerotinia sclerotiorum. Nine susceptible isolates were exposed independently to five commercial fungicides with different modes of action: boscalid (respiration inhibitor, iprodione (unclear mode of action, thiophanate methyl (inhibition of microtubulin synthesis and azoxystrobin and pyraclostrobin (quinone outside inhibitors. Mycelium of each isolate was inoculated onto a fungicide gradient and sub-cultured from the 50-100% inhibition zone for 12 generations and experiment repeated. Mutational changes were assessed for all isolates at six neutral microsatellite (SSR loci and for a subset of isolates using amplified fragment length polymorphisms (AFLPs. SSR analysis showed 12 of 85 fungicide-exposed isolates had a total of 127 stepwise mutations with 42 insertions and 85 deletions. Most stepwise deletions were in iprodione- and azoxystrobin-exposed isolates (n = 40/85 each. Estimated mutation rates were 1.7 to 60-fold higher for mutated loci compared to that expected under neutral conditions. AFLP genotyping of 33 isolates (16 non-exposed control and 17 fungicide exposed generated 602 polymorphic alleles. Cluster analysis with principal coordinate analysis (PCoA and discriminant analysis of principal components (DAPC identified fungicide-exposed isolates as a distinct group from non-exposed control isolates (PhiPT = 0.15, P = 0.001. Dendrograms based on neighbor-joining also supported allelic variation associated with fungicide-exposure. Fungicide sensitivity of isolates measured throughout both experiments did not show consistent trends. For example, eight isolates exposed to boscalid had higher EC50 values at the end of the

  17. The effect of the Falcon 460 EC fungicide on soil microbial communities, enzyme activities and plant growth.

    Science.gov (United States)

    Baćmaga, Małgorzata; Wyszkowska, Jadwiga; Kucharski, Jan

    2016-10-01

    Fungicides are considered to be effective crop protection chemicals in modern agriculture. However, they can also exert toxic effects on non-target organisms, including soil-dwelling microbes. Therefore, the environmental fate of fungicides has to be closely monitored. The aim of this study was to evaluate the influence of the Falcon 460 EC fungicide on microbial diversity, enzyme activity and resistance, and plant growth. Samples of sandy loam with pH KCl 7.0 were collected for laboratory analyses on experimental days 30, 60 and 90. Falcon 460 EC was applied to soil in the following doses: control (soil without the fungicide), dose recommended by the manufacturer, 30-fold higher than the recommended dose, 150-fold higher than the recommended dose and 300-fold higher than the recommended dose. The observed differences in the values of the colony development index and the eco-physiological index indicate that the mixture of spiroxamine, tebuconazole and triadimenol modified the biological diversity of the analyzed groups of soil microorganisms. Bacteria of the genus Bacillus and fungi of the genera Penicillium and Rhizopus were isolated from fungicide-contaminated soil. The tested fungicide inhibited the activity of dehydrogenases, catalase, urease, acid phosphatase and alkaline phosphatase. The greatest changes were induced by the highest fungicide dose 300-fold higher than the recommended dose. Dehydrogenases were most resistant to soil contamination. The Phytotoxkit test revealed that the analyzed fungicide inhibits seed germination capacity and root elongation. The results of this study indicate that excessive doses of the Falcon 460 EC fungicide 30-fold higher than the recommended dose to 300-fold higher than the recommended dose) can induce changes in the biological activity of soil. The analyzed microbiological and biochemical parameters are reliable indicators of the fungicide's toxic effects on soil quality.

  18. Antiandrogenic effects in vitro and in vivo of the fungicide prochloraz

    DEFF Research Database (Denmark)

    Vinggaard, Anne Marie; Nellemann, Christine; Dalgaard, Majken

    2002-01-01

    The commonly used imidazole fungicide prochloraz was tested for antiandrogenic effects in vitro and in vivo. Prochloraz, but not the metabolites 2,4,6-trichlorophenoxyacetic acid or 2,4,6-trichlorophenol, inhibited the R1881-induced response in an androgen receptor reporter gene assay. In the Her......The commonly used imidazole fungicide prochloraz was tested for antiandrogenic effects in vitro and in vivo. Prochloraz, but not the metabolites 2,4,6-trichlorophenoxyacetic acid or 2,4,6-trichlorophenol, inhibited the R1881-induced response in an androgen receptor reporter gene assay...

  19. Effectiveness of Different Classes of Fungicides on Botrytis cinerea Causing Gray Mold on Fruit and Vegetables

    Directory of Open Access Journals (Sweden)

    Joon-Oh Kim

    2016-12-01

    Full Text Available Botrytis cinerea is a necrotrophic pathogen causing a major problem in the export and post-harvest of strawberries. Inappropriate use of fungicides leads to resistance among fungal pathogens. Therefore, it is necessary to evaluate the sensitivity of B. cinerea to various classes of fungicide and to determine the effectiveness of different concentrations of commonly used fungicides. We thus evaluated the effectiveness of six classes of fungicide in inhibiting the growth and development of this pathogen, namely, fludioxonil, iprodione, pyrimethanil, tebuconazole, fenpyrazamine, and boscalid. Fludioxonil was the most effective (EC₅₀ < 0.1 μg/ml, and pyrimethanil was the least effective (EC₅₀ = 50 μg/ml, at inhibiting the mycelial growth of B. cinerea. Fenpyrazamine and pyrimethanil showed relatively low effectiveness in inhibiting the germination and conidial production of B. cinerea. Our results are useful for the management of B. cinerea and as a basis for monitoring the sensitivity of B. cinerea strains to fungicides.

  20. Development of a novel multiplex DNA microarray for Fusarium graminearum and analysis of azole fungicide responses

    Directory of Open Access Journals (Sweden)

    Deising Holger B

    2011-01-01

    Full Text Available Abstract Background The toxigenic fungal plant pathogen Fusarium graminearum compromises wheat production worldwide. Azole fungicides play a prominent role in controlling this pathogen. Sequencing of its genome stimulated the development of high-throughput technologies to study mechanisms of coping with fungicide stress and adaptation to fungicides at a previously unprecedented precision. DNA-microarrays have been used to analyze genome-wide gene expression patterns and uncovered complex transcriptional responses. A recently developed one-color multiplex array format allowed flexible, effective, and parallel examinations of eight RNA samples. Results We took advantage of the 8 × 15 k Agilent format to design, evaluate, and apply a novel microarray covering the whole F. graminearum genome to analyze transcriptional responses to azole fungicide treatment. Comparative statistical analysis of expression profiles uncovered 1058 genes that were significantly differentially expressed after azole-treatment. Quantitative RT-PCR analysis for 31 selected genes indicated high conformity to results from the microarray hybridization. Among the 596 genes with significantly increased transcript levels, analyses using GeneOntology and FunCat annotations detected the ergosterol-biosynthesis pathway genes as the category most significantly responding, confirming the mode-of-action of azole fungicides. Cyp51A, which is one of the three F. graminearum paralogs of Cyp51 encoding the target of azoles, was the most consistently differentially expressed gene of the entire study. A molecular phylogeny analyzing the relationships of the three CYP51 proteins in the context of 38 fungal genomes belonging to the Pezizomycotina indicated that CYP51C (FGSG_11024 groups with a new clade of CYP51 proteins. The transcriptional profiles for genes encoding ABC transporters and transcription factors suggested several involved in mechanisms alleviating the impact of the fungicide

  1. Potential of Cerbera odollam as a bio-fungicide for post-harvest pathogen Penicilium digitatum

    Science.gov (United States)

    Singh, Harbant; Yin-Chu, Sue; Al-Samarrai, Ghassan; Syarhabil, Muhammad

    2015-05-01

    Postharvest diseases due to fungal infection contribute to economic losses in agriculture industry during storage, transportation or in the market. Penicillium digitatum is one of the common pathogen responsible for the postharvest rot in fruits. This disease is currently being controlled by synthetic fungicides such as Guazatine and Imazalil. However, heavy use of fungicides has resulted in environmental pollution, such as residue in fruit that expose a significant risk to human health. Therefore, there is a strong need to develop alternatives to synthetic fungicide to raise customer confidence. In the current research, different concentrations (500 to 3000 ppm) of ethanol extract of Cerbera odollam or commonly known as Pong-pong were compared with Neem and the controls (Positive control/Guazatine; Negative control/DMSO) for the anti-fungicide activity in PDA media contained in 10 cm diameter Petri dishes, using a modification of Ruch and Worf's method. The toxicity (Lc50) of the C.odollam extract was determined by Brine-shrimp test (BST). The results of the research indicated that crude extraction from C.odollam showed the highest inhibition rate (93%) and smallest colony diameter (0.63 cm) at 3000 ppm in vitro compared with Neem (inhibition rate: 88%; colony diameter: 1.33 cm) and control (Positive control/Guazatine inhibition rate: 79%, colony diameter: 1.9 cm; Negative control/DMSO inhibition rate: 0%, colony diameter: 9.2 cm). C.odollam recorded Lc50 value of 5 µg/ml which is safe but to be used with caution (unsafe level: below 2 µg/ml). The above anti-microbial activity and toxicity value results indicate that C.odollam has a potential of being a future bio-fungicide that could be employed as an alternative to synthetic fungicide.

  2. Evaluation of some fungicides on mycorrhizal symbiosis between two Glomus species from commercial inocula and Allium porrum L. seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Dorrego, A.; Mestre Pares, J.

    2010-07-01

    This paper reports the effect of twenty-five commonly used fungicides in agriculture on two arbuscular mycorrhizal fungi (AMF) present in commercial products of ATENS, S.L.: Glomus intra radices (Schenck and Smith) and Glomus mosseae [(Nicol. and Gerd.) Gerdemann and Trappe], forming the symbiosis with leek plants. Systemic fungicides (Aliette, Beltanol, Caddy 10, Forum, Moncut, Ortiva, Previcur, Ridomil Gold MZ, Ridomil Gold SL, Rubigan, Sinthane, Stroby, Swich, Tachigarem, Teldor, Topas 10 EC, Frupica) and non systemic fungicides (Daconil 75%, Ditiver, Euparem, INACOP, Octagon, Parmex, Terrazole and Metaram), started to be applied to soil and leaves at recommended concentrations and frequencies 4 weeks after transplant and AMF inoculation. The effect of the fungicides was assessed by comparing treated and untreated plants that were inoculated with the AMF through quantification of root mycorrhizal colonization. Among the fungicides applied to the soil, Octagon, Ditiver, Parmex and Metaram virtually eliminated the mycorrhizal symbiosis in treated plants, while the mycorrhizal colonization was not affected by the soil treatment with Beltanol, INACOP and Previcur. Three fungicides of foliar recommended application: Rubigan, Frupica, and Sinthane, strongly inhibited mycorrhizal colonization, but Aliette, Forum, Teldor, Swich and Ortiva, did not seem to reduce it substantially. In addition, the work describes the individual effect of each fungicide applied on both, foliage and soil. (Author) 29 refs.

  3. Gene transcription profiling of Fusarium graminearum treated with an azole fungicide tebuconazole.

    Science.gov (United States)

    Liu, Xin; Jiang, Jinhua; Shao, Jiaofang; Yin, Yanni; Ma, Zhonghua

    2010-01-01

    Using a deep serial analysis of gene expression (DeepSAGE) sequencing approach, we profiled the transcriptional response of Fusarium graminearum to tebuconazole, a most widely used azole fungicide. By comparing the expression of genes in F. graminearum treated and untreated with tebuconazole, we identified 324 and 155 genes showing more than a 5-fold increase and decrease, respectively, in expression upon tebuconazole treatment. These genes are involved in a variety of cell functions including egrosterol biosynthesis, transcription, and cellular metabolism. The validity of DeepSAGE results were confirmed by real-time PCR analysis of expression of 20 genes with different expression levels in the DeepSAGE analysis. The results from this study provide useful information in understanding the mechanisms for the responses of F. graminearum to azole fungicides.

  4. Inhibition of chlorophyll biosynthesis at the protochlorophyllide reduction step results in the parallel depletion of Photosystem I and Photosystem II in the cyanobacterium Synechocystis PCC 6803

    Czech Academy of Sciences Publication Activity Database

    Kopečná, Jana; Sobotka, Roman; Komenda, Josef

    2013-01-01

    Roč. 237, č. 2 (2013), s. 497-508 ISSN 0032-0935 R&D Projects: GA ČR GAP501/10/1000; GA ČR GBP501/12/G055; GA MŠk(CZ) ED2.1.00/03.0110 Institutional support: RVO:61388971 Keywords : Chlorophyll biosynthesis * Cyanobacteria * Photosystems Subject RIV: EE - Microbiology, Virology Impact factor: 3.376, year: 2013

  5. Arabinogalactan biosynthesis

    DEFF Research Database (Denmark)

    Poulsen, Christian Peter; Dilokpimol, Adiphol; Geshi, Naomi

    2015-01-01

    Arabinogalactan proteins are abundant cell surface proteoglycans in plants and are implicated to act as developmental markers during plant growth. We previously reported that AtGALT31A, AtGALT29A, and AtGLCAT14A-C, which are involved in the biosynthesis of arabinogalactan proteins, localize......GALT29A. Therefore, the electrostatic status of Y144, which is regulated by an unknown kinase/phosphatase system, may regulate AtGALT29A enzyme activity. Moreover, we have identified additional proteins, apyrase 3 (APY3; At1g14240) and UDPglucuronate epimerases 1 and 6 (GAE1, At4g30440; GAE6, At3g23820...

  6. Low-airflow drying of fungicide-treated shelled corn

    International Nuclear Information System (INIS)

    Peterson, W.H.; Benson, P.W.

    1993-02-01

    Approved fungicides inhibit mold growth in shelled corn and allow for longer, natural-air drying. The longer drying periods permit lower than-normal airflows and smaller power units, thus reducing electrical demands on utilities in corn-producing states. Researchers placed approximately 67 m 3 (1900 bu) of one variety of shelled corn at approximately 24% moisture in each of five equally sized storage bins. They partitioned each bin vertically and filled one half of each bin with fungicide-treated corn and one half with untreated corn. Each of four bins used a different airflow. A fifth bin used the lowest of the four airflows but was equipped to capture and use solar energy. All corn dried rapidly with resulting good quality. The percentage of damaged kernels was significantly higher for untreated than for treated corn. The energy required for the lowest airflow system was approximately one half of that required for the higher, more traditional airflows. Because of lower-than-normal airflows, the electrical demand on the utility is approximately one fourth as great as that imposed when the higher, more traditional natural-air systems are used. The 1991 corn growing and drying seasons were unusual in central Illinois, the site of the study. Both harvest and drying occurred several weeks ahead of schedule. Additional work is needed to verify that findings hold true during more-normal Midwest corn growing and drying seasons; the investigators predict that they will. It should be noted that the fungicide used in this study has not yet been approved for widespread use in drying corn

  7. Comparative Assessment of the Effect of Synthetic and Natural Fungicides on Soil Respiration

    Directory of Open Access Journals (Sweden)

    Joanna D’Arc Felício

    2012-03-01

    Full Text Available As toxic pesticide residues may persist in agricultural soils and cause environmental pollution, research on natural fungicides to replace the synthetic compounds is currently increasing. The effect of the synthetic fungicide chlorothalonil and a natural potential fungicide on the soil microbial activity was evaluated here by the substrate-induced respiration by addition of glucose (SIR, as bioindicator in two soils (Eutrophic Humic Gley—GHE and Typic Eutroferric Chernosol—AVEC. The induced soil respiration parameter was followed during 28 days after soil treatment either with chlorathalonil (11 µg·g−1, or the methanolic fraction from Polymnia sonchifolia extraction (300 µg·g−1, and 14C-glucose (4.0 mg and 5.18 Bq of 14C-glucose g−1. The 14C-CO2 produced by the microbial respiration was trapped in NaOH (0.1 M which was changed each two hours during the first 10 h, and 1, 3, 5, 7, 14 and 28 days after the treatments. The methanolic fraction of the plant extract inhibited (2.2% and stimulated (1.8% the respiration of GHE and AVEC, respectively, but the synthetic chlorothalonil caused 16.4% and 2.6% inhibition of the respiration, respectively of the GHE and AVEC soils. As the effects of the natural product were statistically small, this bioindicator indicates that the methanolic fraction of the Polymnia sonchifolia extract, which has fungicide properties, has no environmental effects.

  8. Vacuole-targeting fungicidal activity of amphotericin B

    Directory of Open Access Journals (Sweden)

    Akira eOgita

    2012-03-01

    Full Text Available Invasive fungal infections are recognized as major threats to patients with immune depression as well as those with cancer chemotherapy. Amphotericin B (AmB, a classical antifungal agent with a polyene macrolide structure, is widely used for the control of serious fungal infections. However, the clinical use of this antibiotic is limited by the treatment-associated side effects and the appearance of resistant strains. AmB lethality has been generally elucidated by the alteration of plasma membrane ion permeability due to its specific binding to plasma membrane ergosterol. While, the recent studies with Saccharomyces cerevisiae and Candida albicans reveals the vacuole disruptive action as another cause of AmB lethality on the basis of its marked amplification in combination with allicin, an allyl sulfur compound from garlic. Indeed, AmB causes a serious structural damage to the vacuole membrane at a lethal concentration, and even at a non-lethal concentration in combination with allicin. Such an enhancement effect of allicin is dependent on an inhibition of ergosterol-trafficking from the plasma membrane to the vacuole membrane, which is considered to be a cellular response to protect against the vacuole membrane disintegration. Allicin can also decrease the minimum fungicidal concentration of AmB against the pathogenic fungi C. albicans and Aspergillus fumigatus, as is the case of S. cerevisiae. The synergistic fungicidal activities of AmB and allicin may have significant implications in the development of the vacuole-targeting chemotherapy against fungal infections.

  9. A pesticide paradox: fungicides indirectly increase fungal infections.

    Science.gov (United States)

    Rohr, Jason R; Brown, Jenise; Battaglin, William A; McMahon, Taegan A; Relyea, Rick A

    2017-12-01

    There are many examples where the use of chemicals have had profound unintended consequences, such as fertilizers reducing crop yields (paradox of enrichment) and insecticides increasing insect pests (by reducing natural biocontrol). Recently, the application of agrochemicals, such as agricultural disinfectants and fungicides, has been explored as an approach to curb the pathogenic fungus, Batrachochytrium dendrobatidis (Bd), which is associated with worldwide amphibian declines. However, the long-term, net effects of early-life exposure to these chemicals on amphibian disease risk have not been thoroughly investigated. Using a combination of laboratory experiments and analysis of data from the literature, we explored the effects of fungicide exposure on Bd infections in two frog species. Extremely low concentrations of the fungicides azoxystrobin, chlorothalonil, and mancozeb were directly toxic to Bd in culture. However, estimated environmental concentrations of the fungicides did not reduce Bd on Cuban tree frog (Osteopilus septentrionalis) tadpoles exposed simultaneously to any of these fungicides and Bd, and fungicide exposure actually increased Bd-induced mortality. Additionally, exposure to any of these fungicides as tadpoles resulted in higher Bd abundance and greater Bd-induced mortality when challenged with Bd post-metamorphosis, an average of 71 d after their last fungicide exposure. Analysis of data from the literature revealed that previous exposure to the fungicide itraconazole, which is commonly used to clear Bd infections, made the critically endangered booroolong frog (Litoria booroolongensis) more susceptible to Bd. Finally, a field survey revealed that Bd prevalence was positively associated with concentrations of fungicides in ponds. Although fungicides show promise for controlling Bd, these results suggest that, if fungicides do not completely eliminate Bd or if Bd recolonizes, exposure to fungicides has the potential to do more harm than

  10. SYNTHESIS AND FUNGICIDAL ACTIVITY OF ACETYL ...

    African Journals Online (AJOL)

    a

    large varieties of new sulfur based crop protection chemicals in development around the world. [14, 15]. Methods ... sulfur fission viz, the resonance – stabilized benzyl (or isomeric tropylium) cation [19]. The elimination of ... two well – established fungicides so as to compare their activities with those of compounds 1(a. – d).

  11. Fungicide and insecticide residues in rice grains

    Directory of Open Access Journals (Sweden)

    Gustavo Mack Teló

    2017-01-01

    Full Text Available The objective of this study was to analyse residues of fungicides and insecticides in rice grains that were subjected to different forms of processing. Field work was conducted during three crop seasons, and fungicides and insecticides were applied at different crop growth stages on the aerial portion of the rice plants. Azoxystrobin, difenoconazole, propiconazole, tebuconazole, and trifloxystrobin fungicides were sprayed only once at the R2 growth stage or twice at the R2 and R4 growth stages; cypermethrin, lambda-cyhalothrin, permethrin, and thiamethoxam insecticides were sprayed at the R2 growth stage; and permethrin was sprayed at 5-day intervals from the R4 growth stage up to one day prior to harvest. Pesticide residues were analysed in uncooked, cooked, parboiled, polished and brown rice grains as well as rice hulls during the three crop seasons, for a total of 1458 samples. The samples were analysed by gas chromatography with electron capture detection (GC-ECD using modified QuEChERS as the extraction method. No fungicide or insecticide residues were detected in rice grain samples; however, azoxystrobin and cypermethrin residues were detected in rice hull samples.

  12. Screening Phytophthora rubi for fungicide resistance

    Science.gov (United States)

    Preliminary results from the survey for fungicide resistance in Phytophthora were reported at the 2016 Washington Small Fruit Conference. Phytophthora was isolated from diseased plants in 28 red raspberry fields and tested against mefenoxam, the active ingredient of Ridomil. Most isolates were ident...

  13. SYK Inhibition Modulates Distinct PI3K/AKT-dependent Survival Pathways and Cholesterol Biosynthesis in Diffuse Large B-cell Lymphomas

    Science.gov (United States)

    Chen, Linfeng; Monti, Stefano; Juszczynski, Przemyslaw; Ouyang, Jing; Chapuy, Bjoern; Neuberg, Donna; Doench, John G.; Bogusz, Agata M.; Habermann, Thomas M.; Dogan, Ahmet; Witzig, Thomas E.; Kutok, Jeffery L.; Rodig, Scott J.; Golub, Todd; Shipp, Margaret A.

    2013-01-01

    SUMMARY B-cell receptor (BCR) signaling pathway components represent promising treatment targets in diffuse large B-cell lymphoma (DLBCL) and additional B-cell tumors. BCR signaling activates spleen tyrosine kinase (SYK) and downstream pathways including PI3K/AKT and NF-κB. In previous studies, chemical SYK blockade selectively decreased BCR signaling and induced apoptosis of BCR-dependent DLBCLs. Herein, we characterize distinct SYK/PI3K-dependent survival pathways in DLBCLs with high or low baseline NF-κB activity including selective repression of the pro-apoptotic HRK protein in NF-κB-low tumors. We also define SYK/PI3K-dependent cholesterol biosynthesis as a feed-forward mechanism of maintaining the integrity of BCRs in lipid rafts in DLBCLs with low or high NF-κB. In addition, SYK amplification and PTEN deletion are identified as selective genetic alterations in primary “BCR”-type DLBCLs. PMID:23764004

  14. SYK inhibition modulates distinct PI3K/AKT- dependent survival pathways and cholesterol biosynthesis in diffuse large B cell lymphomas.

    Science.gov (United States)

    Chen, Linfeng; Monti, Stefano; Juszczynski, Przemyslaw; Ouyang, Jing; Chapuy, Bjoern; Neuberg, Donna; Doench, John G; Bogusz, Agata M; Habermann, Thomas M; Dogan, Ahmet; Witzig, Thomas E; Kutok, Jeffery L; Rodig, Scott J; Golub, Todd; Shipp, Margaret A

    2013-06-10

    B cell receptor (BCR) signaling pathway components represent promising treatment targets in diffuse large B cell lymphoma (DLBCL) and additional B cell tumors. BCR signaling activates spleen tyrosine kinase (SYK) and downstream pathways including PI3K/AKT and NF-κB. In previous studies, chemical SYK blockade selectively decreased BCR signaling and induced apoptosis of BCR-dependent DLBCLs. Herein, we characterize distinct SYK/PI3K-dependent survival pathways in DLBCLs with high or low baseline NF-κB activity including selective repression of the pro-apoptotic HRK protein in NF-κB-low tumors. We also define SYK/PI3K-dependent cholesterol biosynthesis as a feed-forward mechanism of maintaining the integrity of BCRs in lipid rafts in DLBCLs with low or high NF-κB. In addition, SYK amplification and PTEN deletion are identified as selective genetic alterations in primary "BCR"-type DLBCLs. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Observations on the Behaviour of Different Populations of Plasmopara viticola Resistant to QoI Fungicides in Italian Vineyards

    Directory of Open Access Journals (Sweden)

    M.L. Gullino

    2004-12-01

    Full Text Available Grapevine downy mildew, caused by Plasmopara viticola, is probably the most damaging fungal disease of grapevine world-wide. Among the fungicides recently developed for downy mildew control is the QoI class of fungicides, which inhibits mitochondrial respiration. Since 1999, selected P. viticola populations in northern Italy have been monitored for resistance to QoI fungicides. Detached leaf discs and whole potted plants were used under controlled conditions to test the sampled populations. QoI-resistant populations of P. viticola were found in all the vineyards sampled in 2001 and 2002 in Trentino Alto Adige and Friuli Venezia Giulia, where failure in QoI control was reported. Many of the populations had minimum inhibition concentration (MIC values 3– 30 times higher than those of sensitive reference populations. Populations of P. viticola sampled from vineyards in Piedmont, where no QoI fungicides had previously been used, showed MIC values equal to, or lower than those of the reference populations. Most of the P. viticola populations collected in Trentino Alto Adige in 2001 showed high virulence in leaf disc test and were not controlled by QoI fungicides, applied both at field and double field rates in the whole plant test. Most of these populations retained their virulence in the subsequent leaf disc test in water.

  16. Evaluation of fungicides to protect pruning wounds from Botryosphaeriaceae species infections on almond trees

    Directory of Open Access Journals (Sweden)

    Diego OLMO

    2017-05-01

    Full Text Available In vitro efficacy of ten fungicides was evaluated against four Botryosphaeriaceae spp. (Diplodia seriata, Neofusicoccum luteum, N. mediterraneum and N. parvum associated with branch cankers on almond trees. Cyproconazole, pyraclostrobin, tebuconazole, and thiophanate-methyl were effective for the inhibition of mycelial growth of most of these fungi. An experiment on 3-year-old almond trees evaluated boscalid, mancozeb, thiophanate-methyl, pyraclostrobin and tebuconazole for preventative ability against infections caused by the four pathogens. Five months after pruning and fungicide application, lesion length measurements and isolation percentages showed no significant differences among the four pathogens after they were inoculated onto the trees, and also between the two inoculation times tested (1 or 7 d after fungicide application. Thiophanate-methyl was the most effective fungicide, resulting in the shortest lesion lengths and the lowest isolation percentages from artificially inoculated pruning wounds. This chemical is therefore a candidate for inclusion in integrated disease management, to protect pruning wounds from infections caused by species of Botryosphaeriaceae. This study represents the first approach to development of chemical control strategies for the management of canker diseases caused by Botryosphaeriaceae fungi on almond trees. 

  17. In vitro sensitivity reduction of Fusarium graminearum to DMI and QoI fungicides

    Directory of Open Access Journals (Sweden)

    Aveline Avozani

    2014-12-01

    Full Text Available In Brazil, Fusarium head blight (FHB affecting wheat can cause up to 39.8% damage. Resistant cultivars are not available yet; thus, short-term disease control relies on the use of fungicides. The first step to improve control is to monitor fungal populations that are sensitivity to chemicals in order to achieve efficient FHB management. In vitro experiments were conducted to evaluate the inhibitory concentration (IC50 of fungicides for both mycelial growth and conidial germination of ten Fusarium graminearum isolates. The following demethylation inhibitor (DMI fungicides were tested: metconazole, prothioconazole and tebuconazole. In addition, pyraclostrobin and trifloxystrobin were included, representing QoI fungicides, as well as three co-formulations containing metconazole + pyraclostrobin, prothioconazole + trifloxystrobin, and tebuconazole + trifloxystrobin. For mycelial growth, the overall mean IC50 of isolates was: metconazole 0.07, prothioconazole 0.1, and tebuconazole 0.19 mg/L. For the co-formulations, it was: prothioconazole + trifloxystrobin 0.08, tebuconazole + trifloxystrobin 0.12, and metconazole + pyraclostrobin 0.14 mg/L. Regarding spore germination inhibition, IC50 for prothioconazole + trifloxystrobin was 0.06, for tebuconazole + trifloxystrobin, 0.12 mg/L, for QoI alone pyraclostrobin, was 0.09, and for trifloxystrobin, 0.28 mg/L. There was a sensitivity shift among isolates and the highest fungitoxicity to F. graminearum was confirmed for prothioconazole, metconazole and tebuconazole .

  18. Comparison of dielectric barrier discharge modes fungicidal effect on candida albicans growth

    International Nuclear Information System (INIS)

    Slama, J.; Kriha, V.; Fantova, V.; Julak, J.

    2013-01-01

    Filamentary and quasi-homogeneous mode of dielectric barrier discharge (DBD) was investigated as a plasma source with fungicidal effect on Candida albicans yeast inoculated on Sabouraud agar wafers. As compared with the filamentary DBD mode, the quasi-homogeneous mode had significantly better results: shorter exposition time needed for inhibiting C. albicans yeast, moreover the quasi-homogeneous mode had gentle influence on the agar surface structure.

  19. Mechanisms of action underlying the antiandrogenic effects of the fungicide prochloraz

    DEFF Research Database (Denmark)

    Laier, Peter; Metzdorff, Stine Broeng; Boberg, Julie

    2006-01-01

    The fungicide prochloraz has got multiple mechanisms of action that may influence the demasculinizing and reproductive toxic effects of the compound. In the present study, Wistar rats were dosed perinatally with prochloraz (50 and 150 mg/kg/day) from gestational day (GD) 7 to postnatal day (PND) ...... acts directly on the fetal testis to inhibit steroidogenesis and that this effect is exhibited at protein, and not at genomic, level. (c) 2005 Elsevier Inc. All rights reserved....

  20. Foliar Application of the Fungicide Pyraclostrobin Reduced Bacterial Spot Disease of Pepper

    OpenAIRE

    Beom Ryong Kang; Jang Hoon Lee; Young Cheol Kim

    2018-01-01

    Pyraclostrobin is a broad-spectrum fungicide that inhibits mitochondrial respiration. However, it may also induce systemic resistance effective against bacterial and viral diseases. In this study, we evaluated whether pyraclostrobin enhanced resistance against the bacterial spot pathogen, Xanthomonas euvesicatora on pepper (Capsicum annuum). Although pyraclostrobin alone did not suppressed the in vitro growth of X. euvesicatoria, disease severity in pepper was significantly lower by 69% after...

  1. RNAi inhibition of feruloyl CoA 6'-hydroxylase reduces scopoletin biosynthesis and post-harvest physiological deterioration in cassava (Manihot esculenta Crantz) storage roots.

    Science.gov (United States)

    Liu, Shi; Zainuddin, Ima M; Vanderschuren, Herve; Doughty, James; Beeching, John R

    2017-05-01

    Cassava (Manihot esculenta Crantz) is a major world crop, whose storage roots provide food for over 800 million throughout the humid tropics. Despite many advantages as a crop, the development of cassava is seriously constrained by the rapid post-harvest physiological deterioration (PPD) of its roots that occurs within 24-72 h of harvest, rendering the roots unpalatable and unmarketable. PPD limits cassava's marketing possibilities in countries that are undergoing increased development and urbanisation due to growing distances between farms and consumers. The inevitable wounding of the roots caused by harvesting triggers an oxidative burst that spreads throughout the cassava root, together with the accumulation of secondary metabolites including phenolic compounds, of which the coumarin scopoletin (7-hydroxy-6-methoxy-2H-1-benzopyran-2-one) is the most abundant. Scopoletin oxidation yields a blue-black colour, which suggests its involvement in the discoloration observed during PPD. Feruloyl CoA 6'-hydroxylase is a controlling enzyme in the biosynthesis of scopoletin. The cassava genome contains a seven membered family of feruloyl CoA 6'-hydroxylase genes, four of which are expressed in the storage root and, of these, three were capable of functionally complementing Arabidopsis T-DNA insertion mutants in this gene. A RNA interference construct, designed to a highly conserved region of these genes, was used to transform cassava, where it significantly reduced feruloyl CoA 6'-hydroxylase gene expression, scopoletin accumulation and PPD symptom development. Collectively, our results provide evidence that scopoletin plays a major functional role in the development of PPD symptoms, rather than merely paralleling symptom development in the cassava storage root.

  2. The bitter barricading of prostaglandin biosynthesis pathway: understanding the molecular mechanism of selective cyclooxygenase-2 inhibition by amarogentin, a secoiridoid glycoside from Swertia chirayita.

    Directory of Open Access Journals (Sweden)

    Shantanu Shukla

    Full Text Available Swertia chirayita, a medicinal herb inhabiting the challenging terrains and high altitudes of the Himalayas, is a rich source of essential phytochemical isolates. Amarogentin, a bitter secoiridoid glycoside from S. chirayita, shows varied activity in several patho-physiological conditions, predominantly in leishmaniasis and carcinogenesis. Experimental analysis has revealed that amarogentin downregulates the cyclooxygenase-2 (COX-2 activity and helps to curtail skin carcinogenesis in mouse models; however, there exists no account on selective inhibition of the inducible cyclooxygenase (COX isoform by amarogentin. Hence the computer-aided drug discovery methods were used to unravel the COX-2 inhibitory mechanism of amarogentin and to check its selectivity for the inducible isoform over the constitutive one. The generated theoretical models of both isoforms were subjected to molecular docking analysis with amarogentin and twenty-one other Food and Drug Authority (FDA approved lead molecules. The post-docking binding energy profile of amarogentin was comparable to the binding energy profiles of the FDA approved selective COX-2 inhibitors. Subsequent molecular dynamics simulation analysis delineated the difference in the stability of both complexes, with amarogentin-COX-2 complex being more stable after 40ns simulation. The total binding free energy calculated by MMGBSA for the amarogentin-COX-2 complex was -52.35 KCal/mol against a binding free energy of -8.57 KCal/mol for amarogentin-COX-1 complex, suggesting a possible selective inhibition of the COX-2 protein by the natural inhibitor. Amarogentin achieves this potential selectivity by small, yet significant, structural differences inherent to the binding cavities of the two isoforms. Hypothetically, it might block the entry of the natural substrates in the hydrophobic binding channel of the COX-2, inhibiting the cyclooxygenation step. To sum up briefly, this work highlights the mechanism of the

  3. Initial-rate kinetics of human NMN-adenylyltransferases: substrate and metal ion specificity, inhibition by products and multisubstrate analogues, and isozyme contributions to NAD+ biosynthesis.

    Science.gov (United States)

    Sorci, Leonardo; Cimadamore, Flavio; Scotti, Stefania; Petrelli, Riccardo; Cappellacci, Loredana; Franchetti, Palmarisa; Orsomando, Giuseppe; Magni, Giulio

    2007-04-24

    Initial-rate and product inhibition studies revealed distinctive ordered ternary complex kinetic mechanisms, substrate specificities, and metal ion preferences for the three isozymes of human nicotinamide mononucleotide adenylyl-transferase (NMNAT, EC 2.7.7.1). ATP binds before NMN with nuclear isozyme NMNAT1 and Golgi apparatus NMNAT2, but the opposite order is observed with the mitochondrial isozyme NMNAT3. Only the latter utilizes ITP efficiently in place of ATP, and while NMNH conversion to NADH by NMNAT1 and NMNAT3 occurs at similar rates, conversion by NMNAT2 is much slower. These isozymes can also be discriminated by their action on tiazofurin monophosphate (TrMP), a metabolite of the antineoplastic prodrug tiazofurin. Our finding that TrMP is only a substrate with NMNAT1 and NMNAT3 reveals for the first time an organelle selectivity in the metabolism of this important drug. In search of additional ways to discriminate these isozymes, we synthesized and tested the P1-(nicotinamide/nicotinate-riboside-5')-Pn-(adenosine-5') dinucleotides Np3AD, Np4AD, and Nap4AD. In addition to being highly effective inhibitors, these multisubstrate geometric inhibitors gave inhibition patterns that are consistent with the aforementioned isozyme differences in substrate binding order. Distinctive differences in their substrate specificity and metal ion selectivity also permitted us to quantify individual isozyme contributions to NAD+ formation in human cell extracts.

  4. Rust Inhibitor And Fungicide For Cooling Systems

    Science.gov (United States)

    Adams, James F.; Greer, D. Clay

    1988-01-01

    Mixture of benzotriazole, benzoic acid, and fungicide prevents growth of rust and fungus. Water-based cooling mixture made from readily available materials prevents formation of metallic oxides and growth of fungi in metallic pipes. Coolant remains clear and does not develop thick sludge tending to collect in low points in cooling systems with many commercial rust inhibitors. Coolant compatible with iron, copper, aluminum, and stainless steel. Cannot be used with cadmium or cadmium-plated pipes.

  5. Organometallic mechanism of action and inhibition of the 4Fe-4S isoprenoid biosynthesis protein GcpE (IspG)

    Science.gov (United States)

    Wang, Weixue; Li, Jikun; Wang, Ke; Huang, Cancan; Zhang, Yong; Oldfield, Eric

    2010-01-01

    We report the results of a series of chemical, EPR, ENDOR, and HYSCORE spectroscopic investigations of the mechanism of action (and inhibition) of GcpE, E-1-hydroxy-2-methyl-but-2-enyl-4-diphosphate (HMBPP) synthase, also known as IspG, an Fe4S4 cluster-containing protein. We find that the epoxide of HMBPP when reduced by GcpE generates the same transient EPR species as observed on addition of the substrate, 2-C-methyl-D-erythritol-2, 4-cyclo-diphosphate. ENDOR and HYSCORE spectra of these transient species (using 2H, 13C and 17O labeled samples) indicate formation of an Fe-C-H containing organometallic intermediate, most likely a ferraoxetane. This is then rapidly reduced to a ferracyclopropane in which the HMBPP product forms an η2-alkenyl π- (or π/σ) complex with the 4th Fe in the Fe4S4 cluster, and a similar “metallacycle” also forms between isopentenyl diphosphate (IPP) and GcpE. Based on this metallacycle concept, we show that an alkyne (propargyl) diphosphate is a good (Ki ∼ 300 nM) GcpE inhibitor, and supported again by EPR and ENDOR results (a 13C hyperfine coupling of ∼7 MHz), as well as literature precedent, we propose that the alkyne forms another π/σ metallacycle, an η2-alkynyl, or ferracyclopropene. Overall, the results are of broad general interest because they provide new mechanistic insights into GcpE catalysis and inhibition, with organometallic bond formation playing, in both cases, a key role. PMID:20534554

  6. Tolerance of triazole-based fungicides by biocontrol agents used to control Fusarium head blight in wheat in Argentina.

    Science.gov (United States)

    Palazzini, J M; Torres, A M; Chulze, S N

    2018-02-25

    Fusarium head blight (FHB) caused by Fusarium graminearum species complex is a devastating disease that causes extensive yield and quality losses to wheat around the world. Fungicide application and breeding for resistance are among the most important tools to counteract FHB. Biological control is an additional tool that can be used as part of an integrated management of FHB. Bacillus velezensis RC 218, Brevibacillus sp. RC 263 and Streptomyces sp. RC 87B were selected by their potential to control FHB and deoxynivalenol production. The aim of this work was to test the tolerance of these biocontrol agents to triazole-based fungicides such as Prothioconazole, tebuconazole and metconazole. Bacterial growth was evaluated in Petri dishes using the spread plating technique containing the different fungicides. Bacillus velezensis RC 218 and Streptomyces sp. RC 87B showed better tolerance to fungicides than Brevibacillus sp. RC 263. Complete growth inhibition was observed at concentrations of 20 μg ml -1 for metconazole, 40 μg ml -1 for tebuconazole and 80 μg ml -1 for prothioconazole. The results obtained indicate the possibility of using these biocontrol agents in combination with fungicides as part of an integrated management to control FHB of wheat. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. Triterpenoid biosynthesis in Euphorbia lathyris latex

    International Nuclear Information System (INIS)

    Hawkins, D.R.

    1987-11-01

    The structures of triterpenols, not previously been known, from Euphorbia lathyris latex are reported. A method for quantifying very small amounts of these compounds was developed. Concerning the biochemistry of the latex, no exogenous cofactors were required for the biosynthesis and the addition of compounds such as NADPAH and ATP do not stimulate the biosynthesis. The addition of DTE or a similar anti-oxidant was found to help reduce the oxidation of the latex, thus increasing the length of time that the latex remains active. The requirement of a divalent cation and the preference for Mn in the pellet was observed. The effect of several inhibitors on the biosynthesis of the triterpenoids was examined. Mevinolin was found to inhibit the biosynthesis of the triterpenoids from acetate, but not mevalonate. A dixon plot of the inhibition of acetate incorporation showed an I 50 concentration of 3.2 μM. Fenpropimorph was found to have little or no effect on the biosynthesis. Tridemorph was found to inhibit the biosynthesis of all of the triterpenoids with an I 50 of 4 μM. It was also observed that the cyclopropyl containing triterpenols, cycloartenol and 24-methylenecycloartenol were inhibited much more strongly than those containing an 8-9 double bond, lanosterol and 24-methylenelanosterol. The evidence indicates, but does not definetely prove, that lanosterol and 24-methylenelanosterol are not made from cycloartenol and 24-methylenecycloartenol via a ring-opening enzyme such as cycloeucalenol-obtusifoliol isomerase. The possibilty that cycloartenol is made via lanosterol was investigated by synthesizing 4-R-4- 3 H-mevalonic acid and incubating latex with a mixture of this and 14 C-mevalonic acid. From the 3 H/ 14 C ratio it was shown that cycloartenol and 24-methylenecycloartenol are not made via an intermediate containing as 8-9 double bond. 88 refs., 15 figs., 30 tabs

  8. Alternative fungicides for the leather industry: application in various processes

    OpenAIRE

    Cuadros Domènech, Sara; Manresa Presas, Mª Angels; Font Vallès, Joaquim; Puig Vidal, Rita; Marsal Monge, Agustí

    2012-01-01

    Increasingly stringent environmental legislation and indispensable use of fungicides in the tanning industry obliges tanners to adapt their processes to alternative technologies with lower environmental impact, including the search for new fungicide systems that comply with those rules. The fungicidal capacities of alternative compounds diiodomethyl p-tolylsulfone (DIMPTS), 3-iodo- 2-propynyl N-butylcarbamate (IPBC) and thiabendazole / 2-thiazol-4-yl-1H-benzo imidazole(TBZ) were compared t...

  9. Recent Trends in Studies on Botanical Fungicides in Agriculture

    Directory of Open Access Journals (Sweden)

    Mi-Young Yoon

    2013-03-01

    Full Text Available Plants are attacked by various phytopathogenic fungi. For many years, synthetic fungicides have been used to control plant diseases. Although synthetic fungicides are highly effective, their repeated use has led to problems such as environmental pollution, development of resistance, and residual toxicity. This has prompted intensive research on the development of biopesticides, including botanical fungicides. To date, relatively few botanical fungicides have been registered and commercialized. However, many scientists have reported isolation and characterization of a variety of antifungal plant derivatives. Here, we present a survey of a wide range of reported plant-derived antifungal metabolites.

  10. The Small Regulatory RNA Spot42 Inhibits Indole Biosynthesis to Negatively Regulate the Locus of Enterocyte Effacement of Enteropathogenic Escherichia coli

    Directory of Open Access Journals (Sweden)

    Shantanu Bhatt

    2017-12-01

    Full Text Available The locus of enterocyte effacement is necessary for enteropathogenic Escherichia coli (EPEC to form attaching and effacing (A/E lesions. A/E lesions are characterized by intimate bacterial adherence to intestinal cells and destruction of microvilli, which leads to diarrhea. Therefore, studies interrogating the regulation of the locus of enterocyte effacement (LEE are critical for understanding the molecular epidemiology of EPEC infections and developing interventional strategies. Hitherto, most studies have centered on protein-based regulators, whereas the role of small regulatory RNAs remains underappreciated. Previously, we identified the first sRNAs—MgrR, RyhB, and McaS—that regulate the LEE of EPEC. This study was undertaken to identify additional sRNAs that impact the LEE. Our results suggest that the catabolite-responsive sRNA, Spot42, indirectly controls the LEE by inhibiting synthesis of its inducer, indole. Spot42 base-pairs with the tnaCAB mRNA and presumably destabilizes the transcript, thereby preventing expression of the regulatory and structural proteins that are involved in the import and hydrolysis of tryptophan into indole. The absence of intracellular indole leads to reduced transcription of the LEE1-encoded master transcriptional activator Ler, thereby maintaining the LEE in its silenced state and delaying A/E lesion morphogenesis. Our results highlight the importance of riboregulators that synchronize metabolic and virulence pathways in bacterial infection.

  11. The effect of stereochemistry on the biological activity of natural phytotoxins, fungicides, insecticides and herbicides.

    Science.gov (United States)

    Evidente, Antonio; Cimmino, Alessio; Andolfi, Anna

    2013-02-01

    Phytotoxins are secondary microbial metabolites that play an essential role in the development of disease symptoms induced by fungi on host plants. Although phytotoxins can cause extensive-and in some cases devastating-damage to agricultural crops, they can also represent an important tool to develop natural herbicides when produced by fungi and plants to inhibit the growth and spread of weeds. An alternative strategy to biologically control parasitic plants is based on the use of plant and fungal metabolites, which stimulate seed germination in the absence of the host plant. Nontoxigenic fungi also produce bioactive metabolites with potential fungicide and insecticide activity, and could be applied for crop protection. All these metabolites represent important tools to develop eco-friendly pesticides. This review deals with the relationships between the biological activity of some phytotoxins, seed germination stimulants, fungicides and insecticides, and their stereochemistry. Copyright © 2012 Wiley Periodicals, Inc.

  12. Foliar Application of the Fungicide Pyraclostrobin Reduced Bacterial Spot Disease of Pepper

    Directory of Open Access Journals (Sweden)

    Beom Ryong Kang

    2018-03-01

    Full Text Available Pyraclostrobin is a broad-spectrum fungicide that inhibits mitochondrial respiration. However, it may also induce systemic resistance effective against bacterial and viral diseases. In this study, we evaluated whether pyraclostrobin enhanced resistance against the bacterial spot pathogen, Xanthomonas euvesicatora on pepper (Capsicum annuum. Although pyraclostrobin alone did not suppressed the in vitro growth of X. euvesicatoria, disease severity in pepper was significantly lower by 69% after treatments with pyraclostrobin alone. A combination of pyraclostrobin with streptomycin reduced disease by over 90% that of the control plants. The preventive control of the pyraclostrobin against bacterial spot was required application 1-3 days before pathogen inoculation. Our findings suggest that the fungicide pyraclostrobin can be used with a chemical pesticide to control bacterial leaf spot diseases in pepper.

  13. The presence of bromuconazole fungicide pollutant in organic waste anaerobic fermentation

    Science.gov (United States)

    Hariyadi, H. R.

    2017-03-01

    The presence of bromuconazole fungicide pollutant in organic waste anaerobic fermentation was carried out as well as the influence phenol and benzoate, and biodegradation of bromuconazole. Bromuconazole is a fungicide effective against Ascomycetes, Basidiomycetes and fungi imperfecti in cereals, grapes, top fruits and vegetables. It is also effective against Alternaria and Fusarium sp. The remaining fungicide in leaves might contaminates landfill. One month of organic waste added with bromuconazole was anaerobically incubated in 500 mL bottles at 30°C without shaking in dark room. High-Performance Liquid Chromatography (HPLC) with UV detector and a 100 RP 185μm Lichrosphere column was used to determine bromuconazole concentration. Methane content was determined by Gas Chromatography (GC) method equipped with a flame ionization detector and a metal column packed with 5% neopentyl glycol sebacate and 1% H3PO4 on Chromosorb W-AW (mesh 80-100). After incubation for 225 days, bromuconazole of 200 mg/L inhibited the production of methane (99.5 mM) significantly, but did not inhibit the production of volatile fatty acids. The addition of 100 mg/L phenol or 146 mg/L benzoate increased the production of methane, 143 mM and 135.2 mM, respectively compared with control (121.8 mM). In anaerobic conditions, the presence of toxic pollutants such as fungicide bromuconazole in landfills sites may cause further problems with the accumulation of volatile fatty acids in leachate. Further study to determine the threshold, the presence of bromconazole in low concentration (less than 200 mg/L) on the methane production is recommended.

  14. Fungicidal effect of bacteriocins harvested from Bacillus spp.

    Directory of Open Access Journals (Sweden)

    Adetunji, V. O.

    2013-01-01

    Full Text Available Aims: This study investigated the ability of bacteriocins isolated from Bacillus spp. (Bacillus species to inhibit fourdifferent yeast isolates obtained from common food products (nono, yoghurt, ogi and cheese commonly consumed byNigerians with minimal heat treatment.Methodology and results: Forty-five Bacillus spp. was isolated and identified from common food products usingcultural, morphological, physiological and biochemical characteristics. These isolates were tested for antimicrobialactivity against Salmonella enteritidis (3, Micrococcus luteus (1 and Staphylococcus aureus (2. Eight bacteriocinproducing strains were identified from an over- night broth culture centrifugated at 3500 revolutions for five minutes.Fungicidal effects of these bacteriocins were tested against four yeast strains using the Agar Well Diffusion method. Thebacteriocins produced wide zones of inhibition ranging from 5.9±0.000 to 24.00±0.000 mm against the 4 yeast strainstested. There was a significant difference (at p<0.05 between the yeast organisms and the bacteriocins from theBacillus spp.Conclusion, significance and impact of study: The study reveals the antifungal property of bacteriocins from Bacillusspp. and serves therefore as a base for further studies in its use in the control of diseases and extension of shelf-life ofproducts prone to fungi contamination.

  15. Hydrogen peroxide as a fungicide for fish culture

    Science.gov (United States)

    Dawson, V.K.; Rach, J.J.; Schreier, Theresa M.

    1994-01-01

    Antifungal agents are needed to maintain healthy stocks of fish in the intensive culture systems currently employed in fish hatcheries. Malachite green has been the most widely used antifungal agent; however, its potential for producing teratology in animals and fish precludes further use in fish culture. Preliminary studies at the National Fisheries Research Center, La Crosse, WI, USA (La Crosse Center) indicate that hydrogen peroxide is effective for control of Saprolegnia sp. fungus on incubating eggs of rainbow trout. It is also effective against a wide variety of other organisms such as bacteria, yeasts, viruses, and spores, and has been proposed as a treatment for sea lice on salmon. Hydrogen peroxide and its primary decomposition products, oxygen and water, are not systemic poisons and are considered environmentally compatible. In response to a petition from the La Crosse Center, the U.S. Food and Drug Administration (FDA) recently classified hydrogen peroxide as a 'low regulatory priority' when used for control of fungus on fish and fish eggs. Preliminary tests conducted at the La Crosse Center suggest that prophylactic treatments of 250 to 500 ppm (based on 100% active ingredient) for 15 minutes every other day will inhibit fungal infections on healthy rainbow trout (Oncorhynchus mykiss) eggs. This treatment regime also seems to inhibit fungal development and increase hatching success among infected eggs. Efficacy and safety of hydrogen peroxide as a fungicide for fish are currently being evaluated.

  16. Comparison of the activity of antifungal hexapeptides and the fungicides thiabendazole and imazalil against postharvest fungal pathogens.

    Science.gov (United States)

    López-García, Belén; Veyrat, Ana; Pérez-Payá, Enrique; González-Candelas, Luis; Marcos, Jose F

    2003-12-31

    In this study, we evaluated the activity of short antimicrobial peptides against different fungal isolates that cause postharvest decay of fresh fruits. The previously identified hexapeptides PAF19, PAF26 and LfcinB4-9 inhibited the in vitro growth of isolates from Penicillium digitatum and P. italicum, and from Alternaria and Geotrichum genera, being no active against Rhizopus, Mucor and Aspergillus. The results extend our previous observations on the specific and distinct activity profiles of this class of antifungal peptides. In addition, peptide activities were compared with that of two fungicides used for citrus fruit preservation, thiabendazole (TBZ) and imazalil (IMZ). We observed a lack of correlation between peptide and fungicide sensitivity among different species. Importantly, P. digitatum and P. italicum isolates resistant to fungicides were susceptible to peptides and our data suggest that common multiple drug resistance mechanisms are not active against this class of peptides. The in vitro peptide inhibition was correlated with a retard of the decay caused by Penicillium on citrus fruits, and this effect was comparable for both fungicide-resistant and -sensitive isolates. Comparison of PAF26 and TBZ in vitro minimum inhibitory concentration (MIC) values and their in vivo effect on citrus decay indicated that PAF26 performed in vivo better than TBZ.

  17. Development of biodegradable fungicide by radiation

    International Nuclear Information System (INIS)

    Lee, Young Jeun; Kim, Dong Sub

    2010-01-01

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Sixteen antifungal microbes were isolated and 4 antifungal activity enhanced mutants were induced by using radiation. P. lentimorbus WJ5a17 had 41% higher antifungal activity than the wild type. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified

  18. Development of biodegradable fungicide by radiation

    International Nuclear Information System (INIS)

    Lee, Young Keun; Kim, Dong Sub

    2011-01-01

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by pot experiment and It was promising to prevent pepper, Chinese cabbage and radish from anthrax, phytophthora and root rot

  19. Development of biodegradable fungicide by radiation

    International Nuclear Information System (INIS)

    Lee, Youngkeun; Kim, Dongsub

    2012-03-01

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by field test and it was promising to prevent Chinese cabbage and radish from phytophthora and root rot

  20. Development of biodegradable fungicide by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Keun; Kim, Dong Sub [KAERI, Daejeon (Korea, Republic of)

    2011-01-15

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by pot experiment and It was promising to prevent pepper, Chinese cabbage and radish from anthrax, phytophthora and root rot

  1. Development of biodegradable fungicide by radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngkeun; Kim, Dongsub

    2012-03-15

    To develop the fungicide which is biodegradable and alternative to chemical pesticide that has an side effect of environmental pollution, Mutant induction of the enhanced antifungal activity was studied by using radiation. Characteristics and structure of antifungal biomaterials derived from these mutants were analysed. Two biomaterials related to the antifungal activity from the above mutant were isolated and purified. Microbial pesticide were manufactured in combination of various additives. Antiphytopathogenic effects were proven by field test and it was promising to prevent Chinese cabbage and radish from phytophthora and root rot.

  2. In vitro screening of fungicides and antagonists against Sclerotium ...

    African Journals Online (AJOL)

    A study was conducted in the microbiology laboratory of Plant Pathology Department, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, during 2010 to 2011 to control Sclerotium rolfsii with fungicides and Trichoderma harzianum. Six fungicides namely Provax-200, Bavistin, Ridomil, Dithane M-45, ...

  3. Coating with fungicide and different doses of fertilizer in vinhatico ...

    African Journals Online (AJOL)

    Thus, the aim of this study was to evaluate and identify the physical and physiological quality of mahogany seeds that are coated with fertilizer and fungicide. The treatments were: seed coating with sand + lime + fungicide with different doses of fertilizers. The seeds were evaluated in the laboratory and in a greenhouse.

  4. A model for fungicide applications in winter wheat

    DEFF Research Database (Denmark)

    Ørum, Jens Erik; Pinnschmidt, Hans; Jørgensen, Lise Nistrup

    2006-01-01

    A statistical prediction of the opitamal fungicide dose and strategy based on expert knowledge and 5 yers' trial data from Denmark......A statistical prediction of the opitamal fungicide dose and strategy based on expert knowledge and 5 yers' trial data from Denmark...

  5. Detoxification of copper fungicide using EDTA-modified cellulosic ...

    African Journals Online (AJOL)

    Pesticides are poisons and can be particularly dangerous when misused or carelessly disposed. The detoxification of a copper fungicide (KOCIDE 101) using maize cob, a cellulosic material, was studied. Based on copper as the active agent (after a sorption period of 1 h), the concentration of the fungicide reduced from an ...

  6. Export papaya post-harvest protection by fungicides and the ...

    African Journals Online (AJOL)

    Thiabendazole-treated fruits did not rot 21 days after treatment and this fungicide was the most satisfactory with detected residues lower than the European Union's 2000/48/EC guideline. Key Words: Post-harvest, papaya, fungicides, phytotoxic, thiabendazole, residues maximal limit. African Journal of Biotechnology ...

  7. Oral Toxicity of Agro-Fungicides: Tilt (Propiconazole), Bayleton ...

    African Journals Online (AJOL)

    Introduction: The hazard use of pesticides, emergence of many diseases with high prevalence e.g (cancer, kidney failure and hepatic problems) urged the need for research on fungicides which are continuously received by human in Sudan via fruit and vegetables. Objective: To detect the toxicity of these fungicides in ...

  8. Factors influencing activity of triazole fungicides towards Botrytis cinerea.

    NARCIS (Netherlands)

    Stehmann, C.; Waard, de M.A.

    1996-01-01

    The activity of triazole fungicides towards Botrytis cinerea was investigated in vitro (radial growth on fungicide-amended agar) and in vivo (foliar-sprayed tomato plants and dip-treated grapes). In both tests the benzimidazoles, benomyl and thiabendazole, and the dicarboximides, iprodione and

  9. Pathogenicity and fungicide sensitivity of the causal agent of ...

    African Journals Online (AJOL)

    The pathogenicity of the fungus and its cross-infection potential were determined on mango, avocado, papaya and banana fruits. The sensitivity of the pathogen to fungicides was determined by assessing radial mycelial growth on potato dextrose agar (PDA) amended with nine different fungicides (Bendazim, Funguran, ...

  10. Human lysozyme has fungicidal activity against nasal fungi.

    Science.gov (United States)

    Woods, Charmaine M; Hooper, David N; Ooi, Eng H; Tan, Lor-Wai; Carney, A Simon

    2011-01-01

    The cationic antimicrobial peptide lysozyme is the most prevalent innate immune protein in nasal secretions but there is a paucity of research regarding its role in paranasal sinus disease. Lysozyme is generally regarded as an antibacterial agent; however, some data suggest activity toward yeast. This study was designed to determine if lysozyme displays fungicidal activity toward fungi commonly identified in patients with chronic rhinosinusitis (CRS) or fungal sinusitis. Using a colony-forming unit assay the fungicidal activity of lysozyme (0, 0.5, 5, and 50 micromolar; 0- to 7-hour treatment) was tested against strains of Aspergillus fumigatus, the yeast Candida albicans, and other fungi commonly identified in mucin of patients with CRS. Fungi cultured directly from the mucin of two CRS patients were also tested to determine if they were resistant to the fungicidal activity of lysozyme. The fungicidal effect of lysozyme was both concentration and time dependent. After 7-hour treatment lysozyme (5 micromolar) had >80% fungicidal activity against A. fumigatus, Penicillium sp., Acremonium sp., C. albicans, and Candida parapsilosis. The fungicidal activity of lysozyme toward Alternaria alternata could not be determined. Lysozyme was also fungicidal toward the clinical isolates A. fumigatus and Aspergillus terreus cultured from the mucin of CRS patients. Lysozyme displays fungicidal activity toward many fungi commonly identified in patients with CRS, as well as clinical fungi isolates cultured from the mucin of CRS patients. Additional studies are required to determine the regulation of lysozyme in CRS.

  11. Impact of Fungicide Residues on Polymerase Chain Reaction and on Yeast Metabolism

    Directory of Open Access Journals (Sweden)

    Gildo Almeida da Silva

    Full Text Available ABSTRACT The indiscriminate use of pesticides on grape crops is harmful for consumers´ healthin “in natura” consumption and in the ingestion of wine and grape juice. During winemaking, a rapid and efficient fermentation stage is critical to avoid proliferation of contaminating microorganisms and to guarantee the product´s quality. Polymerase chain reaction (PCR has the advantage of detecting these contaminants in the early stages of fermentation. However,this enzymatic reaction may also be susceptible to specific problems, reducing its efficiency. Agricultural practices, such as fungicide treatments, may be a source of PCR inhibiting factors and may also interfere in the normal course of fermentation.The action of the pesticides captan and folpet on PCR and on yeast metabolism was evaluated, once these phthalimide compounds are widely employed in Brazilian vineyards. DNA amplification was only observed at 75 and 37.5 µg/mL of captan concentrations, whereas with folpet, amplification was observed only in the two lowest concentrations tested (42.2 and 21.1µg/mL.Besides the strong inhibition on Taq polymerase activity, phthalimides also inhibited yeast metabolism at all concentrations analyzed.Grape must containing captan and folpet residues could not be transformed into wine due to stuck fermentation caused by the inhibition of yeast metabolism. Non-compliance with the waiting period for phthalimide fungicides may result in financial liabilities to the viticulture sector.The use of yeasts with high fungicide sensitivity should be selected for must fermentation as a strategy for sustainable wine production and to assure that products comply with health and food safety standards.

  12. Protective, curative and eradicative activities of fungicides against grapevine rust

    Directory of Open Access Journals (Sweden)

    Francislene Angelotti

    2014-01-01

    Full Text Available The protective, eradicative and curative activities of the fungicides azoxystrobin, tebuconazole, pyraclostrobin+metiram, and ciproconazole against grapevine rust, were determined in greenhouse. To evaluate the protective activity, leaves of potted ´Niagara´ (Vitis labrusca vines were artificially inoculated with an urediniospore suspension of Phakopsora euvitis four, eight or forteen days after fungicidal spray; and to evaluate the curative and eradicative activities, leaves were sprayed with fungicides two, four or eight days after inoculation. Disease severity was assessed 14 days after each inoculation. All tested fungicides present excellent preventive activity against grapevine rust; however, tebuconazole and ciproconazole provide better curative activity than azoxystrobin and pyraclostrobin+metiram. It was observed also that all tested fungicides significantly reduced the germination of urediniospore produced on sprayed leaves.

  13. Effect of gamma radiation on ''in vitro''' efficiency of fungicides

    International Nuclear Information System (INIS)

    Menten, J.O.M.; Oliveira, G.C.X.

    1984-01-01

    The activity of 60 Co gamma radiation on eight fungicides used in post-harvesting treatment of agricultural products, was studied. Rhizoctonia solani was used in biological test as indicator-fungus. The fungicides were submitted to gamma radiation doses of O (control), 1, 10, 100, 1000 and 10.000 kR, samples of the fungicides were added to the PSA culture media to obtain 0, 1, 10 and 100 ppm concentrations of the active component of each product and of each radiation dose. The ED 50 (concentration of fungicide necessary to cause 50% radial reduction of the fungic mycelium) of each fungicide in the different gamma radiation doses was determined. (M.A.C.) [pt

  14. Characterization of Postharvest Fungicide-Resistant Botrytis cinerea Isolates From Commercially Stored Apple Fruit.

    Science.gov (United States)

    Jurick, Wayne M; Macarisin, Otilia; Gaskins, Verneta L; Park, Eunhee; Yu, Jiujiang; Janisiewicz, Wojciech; Peter, Kari A

    2017-03-01

    Botrytis cinerea causes gray mold and is an economically important postharvest pathogen of fruit, vegetables, and ornamentals. Fludioxonil-sensitive B. cinerea isolates were collected in 2011 and 2013 from commercial storage in Pennsylvania. Eight isolates had values for effective concentrations for inhibiting 50% of mycelial growth of 0.0004 to 0.0038 μg/ml for fludioxonil and were dual resistant to pyrimethanil and thiabendazole. Resistance was generated in vitro, following exposure to a sublethal dose of fludioxonil, in seven of eight dual-resistant B. cinerea isolates. Three vigorously growing B. cinerea isolates with multiresistance to postharvest fungicides were further characterized and found to be osmosensitive and retained resistance in the absence of selection pressure. A representative multiresistant B. cinerea strain caused decay on apple fruit treated with postharvest fungicides, which confirmed the in vitro results. The R632I mutation in the Mrr1 gene, associated with fludioxonil resistance in B. cinerea, was not detected in multipostharvest fungicide-resistant B. cinerea isolates, suggesting that the fungus may be using additional mechanisms to mediate resistance. Results from this study show for the first time that B. cinerea with dual resistance to pyrimethanil and thiabendazole can also rapidly develop resistance to fludioxonil, which may pose control challenges in the packinghouse environment and during long-term storage.

  15. Antifungal effectiveness of fungicide and peroxyacetic acid mixture on the growth of Botrytis cinerea.

    Science.gov (United States)

    Ayoub, Fatima; Ben Oujji, Najwa; Chebli, Bouchra; Ayoub, Mohamed; Hafidi, Athman; Salghi, Rachid; Jodeh, Shehdeh

    2017-04-01

    In the attempt to reduce the negative impacts of chemical pesticides on environment and consumer's health, a new plant treatment practice minimizing the amount of pesticides needed during pests and diseases treatments has been developed. Our approach is based on combining the biocide effects of fungicide with the peroxyacetic acid (PAA) one. In this paper, we focused on the in vitro study of the antifungal activity of this combination against Botrytis cinerea, the most redoubtable threat of tomatoes plants in Morocco. First, different concentrations of a peroxyacetic acid product (PERACLEAN ® 5) and two commercially available fungicides SWITCH and SIGNUM were tested separately for their inhibitory effects on the mycelial growth and spores germination of B. cinerea. 100% inhibition of fungal growth was achieved using 16.77 and 14.47 μg/ml of SIGNUM and SWITCH respectively and 1.5% of PERACLEAN ® 5. When combined with 0.5% of the peroxyacetic acid mixture (PERACLEAN ® 5), the pesticides 100% effective concentrations decreased to 0.5 μg/ml for both pesticides. Hence, this approach allowed us to suppress the pathogen while minimizing the amounts of applied fungicides by more than 95%. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Synthesis, fungicidal activity, and structure-activity relationship of 2-oxo- and 2-hydroxycycloalkylsulfonamides.

    Science.gov (United States)

    Li, Xing-Hai; Wu, De-Cai; Qi, Zhi-Qiu; Li, Xiu-Wei; Gu, Zu-Min; Wei, Song-Hong; Zhang, Yang; Wang, Ying-Zi; Ji, Ming-Shan

    2010-11-10

    To explore new potential fungicides, a series of novel compounds, including 11 2-oxocycloalkylsulfonamide (3) and 21 2-hydroxycycloalkylsulfonamide (4) derivatives, were synthesized and their structures were confirmed by (1)H nuclear magnetic resonance (NMR), infrared (IR), and elemental analysis. The results of the bioassay showed that the compounds 3 and 4 possessed excellent fungicidal activity against Botrytis cinerea Pers. both in vitro and in vivo. The fungicidal activity of the compounds with 7- or 8-membered rings is better than those with 5-, 6-, or 12-membered rings. According to the results of the mycelium growth rate test, the EC50 values of the compounds 3C, 4C, 3D, and 4D were 0.80, 0.85, 1.22, and 1.09 μg/mL, respectively, and similar to or better than commercial fungicide procymidone. The bioassay results of spore germination indicated that most of the compounds exhibited obvious inhibitory effects against B. cinerea and the inhibition rates of 2-oxocycloalkylsulfonamides were higher than 2-hydroxycycloalkylsulfonamides, among them. The EC50 values of compounds 3A, 3B17, 3E, and 4A were 4.21, 4.21 3.24, and 5.29 μg/mL, respectively. Those compounds containing 5- or 6-membered rings showed better activity than those containing 7-, 8-, or 12-membered rings. Furthermore, the results of the pot culture test showed that almost all of the compounds had effective control activity in vivo and 2-hydroxycycloalkylsulfonamides were obviously superior to 2-oxocycloalkylsulfonamides. The compounds 3E, 4C and 4D presented higher control efficacy than procymidone and pyrimethanil against gray mold disease on cucumber plants.

  17. Biological characterization of fenpicoxamid, a new fungicide with utility in cereals and other crops.

    Science.gov (United States)

    Owen, W John; Yao, Chenglin; Myung, Kyung; Kemmitt, Greg; Leader, Andrew; Meyer, Kevin G; Bowling, Andrew J; Slanec, Thomas; Kramer, Vincent J

    2017-10-01

    The development of novel highly efficacious fungicides that lack cross-resistance is extremely desirable. Fenpicoxamid (Inatreq™ active) possesses these characteristics and is a member of a novel picolinamide class of fungicides derived from the antifungal natural product UK-2A. Fenpicoxamid strongly inhibited in vitro growth of several ascomycete fungi, including Zymoseptoria tritici (EC 50 , 0.051 mg L -1 ). Fenpicoxamid is converted by Z. tritici to UK-2A, a 15-fold stronger inhibitor of Z. tritici growth (EC 50 , 0.0033 mg L -1 ). Strong fungicidal activity of fenpicoxamid against driver cereal diseases was confirmed in greenhouse tests, where activity on Z. tritici and Puccinia triticina matched that of fluxapyroxad. Due to its novel target site (Q i site of the respiratory cyt bc1 complex) for the cereals market, fenpicoxamid is not cross-resistant to Z. tritici isolates resistant to strobilurin and/or azole fungicides. Across multiple European field trials Z. tritici was strongly controlled (mean, 82%) by 100 g as ha -1 applications of fenpicoxamid, which demonstrated excellent residual activity. The novel chemistry and biochemical target site of fenpicoxamid as well as its lack of cross-resistance and strong efficacy against Z. tritici and other pathogens highlight the importance of fenpicoxamid as a new tool for controlling plant pathogenic fungi. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  18. Orchard factors associated with resistance and cross resistance to sterol demethylation inhibitor fungicides in populations of Venturia inaequalis from Pennsylvania.

    Science.gov (United States)

    Pfeufer, Emily E; Ngugi, Henry K

    2012-03-01

    Orchard management practices, such as destroying of overwintered inoculum and limiting the number of fungicide applications, are often recommended as tactics for slowing the development of resistance to sterol demethylation-inhibitor (DMI) fungicides in populations of Venturia inaequalis. However, there is little quantitative evidence relating the use of such practices to levels of resistance in orchards. The aim of this study was to evaluate the sensitivity of V. inaequalis isolates from Pennsylvania to DMI fungicides, and to identify orchard management factors related to the incidence of resistant isolates. In total, 644 single-spore V. inaequalis cultures obtained from 20 apple orchards in 2008 or 2009 were tested for sensitivity to myclobutanil, fenbuconazole, or difenoconazole. Growers provided management history of the sampled plots. Widespread shifts toward resistance to the three fungicides were noted, with mean effective concentration for 50% inhibition (EC(50)) values of 2.136, 0.786, and 0.187 μg/ml for myclobutanil, fenbuconazole, and difenoconazole, respectively. Cross resistance to the three fungicides was documented in high correlation (Spearman's r > 0.6) between mean EC(50) values for 14 orchards. Based on a 0.5-μg/ml threshold, 66 and 26% of isolates were resistant to myclobutanil and fenbuconazole, respectively, and 22% were cross resistant to the two fungicides. A significant between-year shift toward increased resistance was noted in two of three orchards surveyed in both years. Failure to use dormant copper sprays, older trees, larger orchards, orchards with ≤10 cultivars, and application of >4 DMI sprays were positively correlated (0.0001 4 DMI sprays were four times as likely to be resistant to fenbuconazole (odds ratio = 4.57; P = 0.015). Isolates from orchards without dormant copper sprays were twice as likely to be cross-shifted toward resistance to all three fungicides (odds ratio = 1.76; P = 0.048). Results identify management

  19. Fungicidal properties of two saponins from Capsicum frutescens and the relationship of structure and fungicidal activity.

    Science.gov (United States)

    De Lucca, A J; Boue, S; Palmgren, M S; Maskos, K; Cleveland, T E

    2006-04-01

    Two steroidal saponins have been purified from cayenne pepper (Capsicum frutescens). Both have the same steroidal moiety but differ in the number of glucose moieties: the first saponin has four glucose moieties (molecular mass 1081 Da) and the second contains three glucose moieties (molecular mass 919 Da). Solubility in aqueous solution is less for the saponin containing three glucose moieties than for the one containing four glucose moieties. The larger saponin was slightly fungicidal against the nongerminated and germinating conidia of Aspergillus flavus, A. niger, A. parasiticus, A. fumigatus, Fusarium oxysporum, F. moniliforme, and F. graminearum, whereas, the second saponin (molecular mass 919 Da) was inactive against these fungi. Results indicate that the absence of one glucose molecule affects the fungicidal and aqueous solubility properties of these similar molecules.

  20. Probenazole treatment inhibits anthocyanins biosynthesis via ...

    African Journals Online (AJOL)

    ELO

    2012-01-05

    Jan 5, 2012 ... chemistry and genetics (Hughes et al., 2010; Romero et al., 2008). There exist many correlative evidences for a relationship between anthocyanins and osmotic stress. *Corresponding author. E-mail: bkkuai@fudan.edu.cn. Fax: +86. 21 65642648. Abbreviations: PBZ, Probenazole; SA, salicylic acid; GUS, ...

  1. Potential Mechanisms Underlying Response to Effects of the Fungicide Pyrimethanil from Gene Expression Profiling inSaccharomyces cerevisiae

    OpenAIRE

    Gil, Fátima N.; Becker, Jörg D.; Viegas, Cristina A.

    2014-01-01

    Pyrimethanil is a fungicide mostly applied in vineyards. When misused, residue levels detected in grape must or in the environment may be of concern. The present work aimed to analyze mechanisms underlying response to deleterious effects of pyrimethanil in the eukaryotic model Saccharomyces cerevisiae. Pyrimethanil concentration-dependent effects at phenotypic (inhibition of growth) and transcriptomic levels were examined. For transcriptional profiling, analysis focused on two sublethal expos...

  2. Ant trail pheromone biosynthesis is triggered by a neuropeptide hormone.

    Directory of Open Access Journals (Sweden)

    Man-Yeon Choi

    Full Text Available Our understanding of insect chemical communication including pheromone identification, synthesis, and their role in behavior has advanced tremendously over the last half-century. However, endocrine regulation of pheromone biosynthesis has progressed slowly due to the complexity of direct and/or indirect hormonal activation of the biosynthetic cascades resulting in insect pheromones. Over 20 years ago, a neurohormone, pheromone biosynthesis activating neuropeptide (PBAN was identified that stimulated sex pheromone biosynthesis in a lepidopteran moth. Since then, the physiological role, target site, and signal transduction of PBAN has become well understood for sex pheromone biosynthesis in moths. Despite that PBAN-like peptides (∼200 have been identified from various insect Orders, their role in pheromone regulation had not expanded to the other insect groups except for Lepidoptera. Here, we report that trail pheromone biosynthesis in the Dufour's gland (DG of the fire ant, Solenopsis invicta, is regulated by PBAN. RNAi knock down of PBAN gene (in subesophageal ganglia or PBAN receptor gene (in DG expression inhibited trail pheromone biosynthesis. Reduced trail pheromone was documented analytically and through a behavioral bioassay. Extension of PBAN's role in pheromone biosynthesis to a new target insect, mode of action, and behavioral function will renew research efforts on the involvement of PBAN in pheromone biosynthesis in Insecta.

  3. Effects of selected herbicides and fungicides on growth, sporulation and conidial germination of entomopathogenic fungus Beauveria bassiana.

    Science.gov (United States)

    Celar, Franci A; Kos, Katarina

    2016-11-01

    The in vitro fungicidal effects of six commonly used fungicides, namely fluazinam, propineb, copper(II) hydroxide, metiram, chlorothalonil and mancozeb, and herbicides, namely isoxaflutole, fluazifop-P-butyl, flurochloridone, foramsulfuron, pendimethalin and prosulfocarb, on mycelial growth, sporulation and conidial germination of entomopathogenic fungus Beauveria bassiana (ATCC 74040) were investigated. Mycelial growth rates and sporulation at 15 and 25 °C were evaluated on PDA plates containing 100, 75, 50, 25, 12.5, 6.25 and 0% of the recommended application rate of each pesticide. The tested pesticides were classified in four scoring categories based on reduction in mycelial growth and sporulation. All pesticides, herbicides and fungicides tested had fungistatic effects of varying intensity, depending on their rate in the medium, on B. bassiana. The most inhibitory herbicides were flurochloridone and prosulfocarb, and fluazinam and copper(II) hydroxide were most inhibitory among the fungicides, while the least inhibitory were isoxaflutole and chlorothalonil. Sporulation and conidial germination of B. bassiana were significantly inhibited by all tested pesticides compared with the control treatment. Flurochloridone, foramsulfuron, prosulfocarb and copper(II) hydroxide inhibited sporulation entirely at 100% rate (99-100% inhibition), and the lowest inhibition was shown by fluazifop-P-butyl (22%) and metiram (33%). At 100% dosage, all herbicides in the test showed a high inhibitory effect on conidial germination. Conidial germination inhibition ranged from 82% with isoxaflutole to 100% with fluorochloridone, pendimethalin and prosulfocarb. At 200% dosage, inhibition rates even increased (96-100%). All 12 pesticides tested had a fungistatic effect on B. bassiana of varying intensity, depending on the pesticide and its concentration. B. bassiana is highly affected by some herbicides and fungicides even at very low rates. Flurochloridone, foramsulfuron

  4. Effects of Conazole Fungicides on Spontaneous Activity in Neural Networks

    Science.gov (United States)

    Hexaconazole (HEX), Tetraconazole (TET), Fluconazole (FLU), and Triadimefon (TRI) are conazole fungicides, used to control powdery mildews on crops, and as veterinary and clinical treatments. TRI, a demethylation inhibitor, is neurotoxic in vivo, and previous in vitro experiments...

  5. Profitability of fungicide use decisions among cocoa farmers in south ...

    African Journals Online (AJOL)

    CRIN) recommended fungicide use rate with profit maximization objective of Nigerian cocoa farmers. To achieve this research objective, a cross-sectional survey of cocoa farmers in four local government areas (LGAs) each in Osun and Ondo ...

  6. Federal Insecticide, Fungicide, and Rodenticide Act Section 18 Database

    Data.gov (United States)

    U.S. Environmental Protection Agency — Section 18 of Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) authorizes EPA to allow an unregistered use of a pesticide for a limited time if EPA...

  7. Use of Moroccan medicinal plant extracts as botanical fungicide against citrus blue mould.

    Science.gov (United States)

    Askarne, L; Talibi, I; Boubaker, H; Boudyach, E H; Msanda, F; Saadi, B; Ait Ben Aoumar, A

    2013-01-01

    The aim of this work was to find an alternative to chemical fungicides currently used in the control of postharvest citrus fruit diseases. In this study, we screened eight Moroccan medicinal and aromatic plants extracted with petroleum ether, chloroform, ethyl acetate and methanol for their anti-fungal activity against Penicillium italicum, the causal agent of citrus blue mould. The anti-fungal activity of these extracts was tested based on the disc diffusion method. Petroleum ether extracts of Inula viscosa, Asteriscus graveolens, Bubonium odorum and Thymus leptobotrys and chloroformic extract of Anvillea radiata revealed the highest significant anti-fungal activity with inhibition zones that ranged between 25·83 and 28·33 mm in diameter. In the minimal inhibitory concentration (MIC) study, we observed that petroleum ether extract of I. viscosa was the most effective extract with both the significantly largest halo (27·50 mm) and the lowest MIC (1 mg ml(-1)). The most active plant extracts in in vitro studies were tested in vivo, and results indicated that solvent extracts of the selected plant species significantly decreased the incidence and severity of blue mould, after 7 and 10 days of storage at 20°C. In addition, Halimium umbellatum methanol extract and T. leptobotrys petroleum ether extract completely inhibited the development of P. italicum under both storage periods, and no phytotoxic effects were recorded on citrus fruit. This study demonstrates that plant extracts have a high potential to control blue mould of citrus and will provide a starting point for discovering new compounds with better activity than chemical fungicides currently available. Such natural products therefore represent a sustainable alternative to the use of chemical fungicides. © 2012 The Society for Applied Microbiology.

  8. Sensitivity loss by Corynespora cassiicola, isolated from soybean, to the fungicide carbendazim

    Directory of Open Access Journals (Sweden)

    Aveline Avozani

    2014-09-01

    Full Text Available Soybean target leaf spot, caused by the fungus Corynespora cassiicola, is controlled especially by leaf application of fungicides. In the last seasons, in the central-west region of Brazil, the disease chemical control efficiency has been low. This led to the hypothesis that the control failure could be due to the reduction or loss of the fungus sensitivity to fungicides. To clarify this fact, in vitro experiments were conducted to determine mycelial sensitivity of five C. cassiicola isolates to fungicides. Mycelial growth was assessed based on the growth of the mycelium on the culture medium, in Petri dishes. The medium potato-dextrose-agar was supplemented with the concentrations 0; 0.01; 0.1; 1; 10; 20 and 40 mg/L of the active ingredients carbendazim, cyproconazole, epoxiconazole, flutriafol and tebuconazole. The experiment was conducted and repeated twice in a controlled environment, temperature of 25±2ºC and photoperiod of 12 hours. Data on the percentage of mycelial inhibition were subjected to logarithmic regression analysis and the concentration that inhibits 50% of the mycelial growth (IC50 was calculated. Loss of sensitivity to carbendazim was observed for three fungal isolates, IC50 > 40 mg/L. Considering all five isolates, the IC50 for tebuconazole ranged from 1.89 to 2.80 mg/L, for epoxiconazol from 2.25 to 2.91, for cyproconazole from 9.21 to 20.32 mg/L, and for flutriafol from 0.77 to 2.18 mg/L. In the absence of information on the reference IC50 determined for wild isolates, the lowest values generated in our study can be used as standard to monitor the fungus sensitivity.

  9. Triazole fungicide tebuconazole disrupts human placental trophoblast cell functions.

    Science.gov (United States)

    Zhou, Jinghua; Zhang, Jianyun; Li, Feixue; Liu, Jing

    2016-05-05

    Triazole fungicides are one of the top ten classes of current-use pesticides. Although exposure to triazole fungicides is associated with reproductive toxicity in mammals, limited information is available regarding the effects of triazole fungicides on human placental trophoblast function. Tebuconazole (TEB) is a common triazole fungicide that has been extensively used for fungi control. In this work, we showed that TEB could reduce cell viability, disturb normal cell cycle distribution and induce apoptosis of human placental trophoblast cell line HTR-8/SVneo (HTR-8). Bcl-2 protein expression decreased and the level of Bax protein increased after TEB treatment in HTR-8 cells. The results demonstrated that this fungicide induced apoptosis of trophoblast cells via mitochondrial pathway. Importantly, we found that the invasive and migratory capacities of HTR-8 cells decreased significantly after TEB administration. TEB altered the expression of key regulatory genes involved in the modulation of trophoblast functions. Taken together, TEB suppressed human trophoblast invasion and migration through affecting the expression of protease, hormones, angiogenic factors, growth factors and cytokines. As the invasive and migratory abilities of trophoblast are essential for successful placentation and fetus development, our findings suggest a potential risk of triazole fungicides to human pregnancy. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Chemosensitization of Fusarium graminearum to Chemical Fungicides Using Cyclic Lipopeptides Produced by Bacillus amyloliquefaciens Strain JCK-12

    Directory of Open Access Journals (Sweden)

    Kihyun Kim

    2017-11-01

    Full Text Available Fusarium head blight (FHB caused by infection with Fusarium graminearum leads to enormous losses to crop growers, and may contaminate grains with a number of Fusarium mycotoxins that pose serious risks to human and animal health. Antagonistic bacteria that are used to prevent FHB offer attractive alternatives or supplements to synthetic fungicides for controlling FHB without the negative effects of chemical management. Out of 500 bacterial strains isolated from soil, Bacillus amyloliquefaciens JCK-12 showed strong antifungal activity and was considered a potential source for control strategies to reduce FHB. B. amyloliquefaciens JCK-12 produces several cyclic lipopeptides (CLPs including iturin A, fengycin, and surfactin. Iturin A inhibits spore germination of F. graminearum. Fengycin or surfactin alone did not display any inhibitory activity against spore germination at concentrations less than 30 μg/ml, but a mixture of iturin A, fengycin, and surfactin showed a remarkable synergistic inhibitory effect on F. graminearum spore germination. The fermentation broth and formulation of B. amyloliquefaciens JCK-12 strain reduced the disease incidence of FHB in wheat. Furthermore, co-application of B. amyloliquefaciens JCK-12 and chemical fungicides resulted in synergistic in vitro antifungal effects and significant disease control efficacy against FHB under greenhouse and field conditions, suggesting that B. amyloliquefaciens JCK-12 has a strong chemosensitizing effect. The synergistic antifungal effect of B. amyloliquefaciens JCK-12 and chemical fungicides in combination may result from the cell wall damage and altered cell membrane permeability in the phytopathogenic fungi caused by the CLP mixtures and subsequent increased sensitivity of F. graminearum to fungicides. In addition, B. amyloliquefaciens JCK-12 showed the potential to reduce trichothecenes mycotoxin production. The results of this study indicate that B. amyloliquefaciens JCK-12 could

  11. Chemosensitization ofFusarium graminearumto Chemical Fungicides Using Cyclic Lipopeptides Produced byBacillus amyloliquefaciensStrain JCK-12.

    Science.gov (United States)

    Kim, Kihyun; Lee, Yoonji; Ha, Areum; Kim, Ji-In; Park, Ae Ran; Yu, Nan Hee; Son, Hokyoung; Choi, Gyung Ja; Park, Hae Woong; Lee, Chul Won; Lee, Theresa; Lee, Yin-Won; Kim, Jin-Cheol

    2017-01-01

    Fusarium head blight (FHB) caused by infection with Fusarium graminearum leads to enormous losses to crop growers, and may contaminate grains with a number of Fusarium mycotoxins that pose serious risks to human and animal health. Antagonistic bacteria that are used to prevent FHB offer attractive alternatives or supplements to synthetic fungicides for controlling FHB without the negative effects of chemical management. Out of 500 bacterial strains isolated from soil, Bacillus amyloliquefaciens JCK-12 showed strong antifungal activity and was considered a potential source for control strategies to reduce FHB. B. amyloliquefaciens JCK-12 produces several cyclic lipopeptides (CLPs) including iturin A, fengycin, and surfactin. Iturin A inhibits spore germination of F. graminearum. Fengycin or surfactin alone did not display any inhibitory activity against spore germination at concentrations less than 30 μg/ml, but a mixture of iturin A, fengycin, and surfactin showed a remarkable synergistic inhibitory effect on F. graminearum spore germination. The fermentation broth and formulation of B. amyloliquefaciens JCK-12 strain reduced the disease incidence of FHB in wheat. Furthermore, co-application of B. amyloliquefaciens JCK-12 and chemical fungicides resulted in synergistic in vitro antifungal effects and significant disease control efficacy against FHB under greenhouse and field conditions, suggesting that B. amyloliquefaciens JCK-12 has a strong chemosensitizing effect. The synergistic antifungal effect of B. amyloliquefaciens JCK-12 and chemical fungicides in combination may result from the cell wall damage and altered cell membrane permeability in the phytopathogenic fungi caused by the CLP mixtures and subsequent increased sensitivity of F. graminearum to fungicides. In addition, B. amyloliquefaciens JCK-12 showed the potential to reduce trichothecenes mycotoxin production. The results of this study indicate that B. amyloliquefaciens JCK-12 could be used as an

  12. Biosynthesis of tylophora alkaloids

    International Nuclear Information System (INIS)

    Mulchandani, N.B.; Iyer, S.S.; Badheka, L.P.

    1974-01-01

    Using labelled precursors, biosynthesis of the tylophora alkaloids, tylophorine, tylophorinidine and tylophorinide has been investigated in Tylophora asthmatica plants. The radioactive precursors, phenylalanine-2- 14 C, benzoic acid-1- 14 C, benzoic acid-ring 14 C, acetate-2- 14 C, ornithine-5- 14 C, acetate-2- 14 C, ornithine-5- 14 C and cinnamic acid-2- 14 C were administered to the plants individually by wick technique. Tylophorine was isolated in each case and assayed for its radioactivity to find out the incorporation of the label into it. The results indicate that: (1) phenylalanine via cinnamic acid is an important precursor in the biosynthesis of tylophorine (2) orinithine participates in tylophorine biosynthesis via pyrroline and (3) tylophorinidine may be a direct precursor of tylophorine. (M.G.B.)

  13. Aflatoxin biosynthesis: current frontiers.

    Science.gov (United States)

    Roze, Ludmila V; Hong, Sung-Yong; Linz, John E

    2013-01-01

    Aflatoxins are among the principal mycotoxins that contaminate economically important food and feed crops. Aflatoxin B1 is the most potent naturally occurring carcinogen known and is also an immunosuppressant. Occurrence of aflatoxins in crops has vast economic and human health impacts worldwide. Thus, the study of aflatoxin biosynthesis has become a focal point in attempts to reduce human exposure to aflatoxins. This review highlights recent advances in the field of aflatoxin biosynthesis and explores the functional connection between aflatoxin biosynthesis, endomembrane trafficking, and response to oxidative stress. Dissection of the regulatory mechanisms involves a complete comprehension of the aflatoxin biosynthetic process and the dynamic network of transcription factors that orchestrates coordinated expression of the target genes. Despite advancements in the field, development of a safe and effective multifaceted approach to solve the aflatoxin food contamination problem is still required.

  14. Biosynthesis of components with antifungal activity against Aspergillus spp. using Streptomyces hygroscopicus

    Directory of Open Access Journals (Sweden)

    Dodić Jelena M.

    2015-01-01

    Full Text Available Losses of apple fruit during storage are mainly caused by fungal phytopathogens. Traditionally, postharvest fungal disease is controlled by the application of synthetic fungicides. However, the harmful impact on environment as well as human health largely limits their application. To reduce these problems in agrochemicals usage, new compounds for plant protection, which are eco-friendly, should be developed. The aim of this study is optimization of medium composition in terms of glucose, soybean meal and phosphates content, by applying response surface methodology, for the production of agents with antifungal activity against Aspergillus spp. For biosynthesis was used strain of Streptomyces hygroscopicus isolated from the environment. Experiments were carried out in accordance with Box-Behnken design with three factors on three levels and three repetitions in the central point. Antifungal activity of the obtained cultivation mediums against Aspergillus oryzae and Aspergillus niger was determined, in vitro, using the diffusion - disc method. For determination optimal medium components desirability function was used. Achieved model predicts that the maximum inhibition zone diameter (40.93 mm against test microorganisms is produced when the initial content of glucose, soybean meal and phosphates are 47.77 g/l, 24.54 g/l and 0.98 g/l, respectively. To minimize the consumption of medium components and costs of effluents processing, additional three sets of optimization were made. The chosen method for optimization of medium components was efficient, relatively simple and time and material saving. Obtained results can be used for the further techno-economic analysis of the process to select optimal medium composition for industrial application.

  15. In vitro bactericidal and fungicidal activities of various extracts of saffron (Crocus sativus L. stigmas from Jammu & Kashmir, India

    Directory of Open Access Journals (Sweden)

    Syed Muzaffar

    2016-12-01

    Full Text Available Antimicrobial activities of methanolic and petroleum ether extracts of Croccus sativus L. (saffron stigmas, were tested against various bacterial strains (Proteus vulgaris, Klebsiella pneumonia, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli and fungi (Candida albicans, Aspergillus niger and Aspergillus fumigatus by agar well diffusion method. Minimal inhibitory concentration and minimum bactericidal and fungicidal concentration values of each active extract were also determined. The results showed a strong activity of the petroleum ether and methanolic extracts of saffron stigmas against bacteria and fungi used as test organisms. The results of different antimicrobial assays also indicate that the extracts had significantly higher bactericidal than fungicidal activities (p < 0.05. The results suggest that these extracts can be used in pharmaceutical and food formulations for inhibiting pathogenic bacterial and fungal species.

  16. Bioengineered silver nanoparticles using Curvularia pallescens and its fungicidal activity against Cladosporium fulvum

    Directory of Open Access Journals (Sweden)

    Abdallah M. Elgorban

    2017-11-01

    Full Text Available Microorganisms based biosynthesis of nanomaterials has triggered significant attention, due to their great potential as vast source of the production of biocompatible nanoparticles (NPs. Such biosynthesized functional nanomaterials can be used for various biomedical applications. The present study investigates the green synthesis of silver nanoparticles (Ag NPs using the fungus Curvularia pallescens (C. pallescens which is isolated from cereals. The C. pallescens cell filtrate was used for the reduction of AgNO3 to Ag NPs. To the best of our knowledge C. pallescens is utilized first time for the preparation of Ag NPs. Several alkaloids and proteins present in the phytopathogenic fungus C. pallescens were mainly responsible for the formation of highly crystalline Ag NPs. The as-synthesized Ag NPs were characterized by using UV–Visible spectroscopy, X-ray diffraction and transmission electron microscopy (TEM. The TEM micrographs have revealed that spherical shaped Ag NPs with polydisperse in size were obtained. These results have clearly suggested that the biomolecules secreted by C. pallescens are mainly responsible for the formation and stabilization of nanoparticles. Furthermore, the antifungal activity of the as-prepared Ag NPs was tested against Cladosporium fulvum, which is the major cause of a serious plant disease, known as tomato leaf mold. The synthesized Ag NPs displayed excellent fungicidal activity against the tested fungal pathogen. The extreme zone of reduction occurred at 50 μL, whereas, an increase in the reduction activity is observed with increasing the concentration of Ag NPs. These encouraging results can be further exploited by employing the as synthesized Ag NPs against various pathogenic fungi in order to ascertain their spectrum of fungicidal activity.

  17. In vitro screening of azole fungicides for antiandrogenic effects – comparison with in vivo effects

    DEFF Research Database (Denmark)

    -based assays. In vitro prochloraz proved to be an activator of the aryl hydrocarbon receptor (AhR), to inhibit aromatase activity and to possess antiestrogenic and antiandrogenic effects both in vitro and in vivo. Another two azole fungicides, tebuconazole and epoxiconazole, have now been investigated...... in H295R cells, a cell line, which produces a wide range of steroid hormones in measurable quantities, including testosterone, progesterone and estradiol, a property that makes it suitable as a screening assay to detect effects on steroidogenesis. In the in vitro tebuconazole and epoxiconazole showed...... antiandrogenic effects, and in the H295R cell assay, tebuconazole and epoxiconazole were like prochloraz able to inhibit testosterone and estradiol levels and increase progesterone levels. For the in vivo testing, a study was conducted testing the developmental effects on offspring after prenatal exposure...

  18. Sterol biosynthesis via cycloartenol and other biochemical features related to photosynthetic phyla in the amoeba Naegleria lovaniensis and Naegleria gruberi.

    Science.gov (United States)

    Raederstorff, D; Rohmer, M

    1987-04-15

    The sterols and sterol precursors of two amoebae of the genus Naegleria, Naegleria lovaniensis and Naegleria gruberi were investigated. Cycloartenol, the sterol precursor in photosynthetic organisms, is present in both amoebae. In N. lovaniesis, it is accompanied by lanosterol and parkeol, as well as by the 24,25-dihydro derivatives of these triterpenes. One of the most striking features of these amoebae is the accumulation of 4 alpha-methylsterols which are present in similar amounts as those of 4,4-desmethylsterols (3-5 mg/g, dry weight). 4 alpha-Methylergosta-7,22-dienol was identified as a new compound. Ergosterol was the major 4,4-desmethylsterol, accompanied by small amounts of C27 and other C28 sterols. Treatment of N. lovaniensis with fenpropimorph modified the sterol pattern of this amoeba and inhibited its growth. This fungicide, known to inhibit steps of sterol biosynthesis in fungi and plants, induced the disappearance of 4 alpha-methyl-delta 7-sterols and the appearance of the unusual delta 6,8,22-ergostatrienol as in A. polyphaga. These results might be explained by a partial inhibition of the delta 8----delta 7 isomerase, the small amounts of delta 7-sterols formed being converted into ergosterol which is still present in fenpropimorph-exposed cells. De novo sterol biosynthesis in N. lovaniensis was shown by incorporation of [1-14C]acetate into sterols and sterol precursors, especially cycloartenol. Lanosterol and parkeol were not significantly labelled. Furthermore, [3-3H]squalene epoxide was efficiently cyclized by a cell-free system of this amoeba into cycloartenol, and again no significant radioactivity was detected in lanosterol and parkeol. This shows that cycloartenol, the sterol precursor in plants and algae, is also the sterol precursor in Naegleria species, and that these amoebae, like A. polyphaga, are related by some biosynthetic pathways to photosynthetic phyla. Lanosterol, the sterol precursor in non-photosynthetic phyla (animal and

  19. In vitro sensitivity of Fusarium graminearum isolates to fungicides

    Directory of Open Access Journals (Sweden)

    Aveline Avozani

    2014-09-01

    Full Text Available Head blight of wheat is a disease of global importance. In Brazil, it can cause damage of up to 27%. As resistant cultivars are not available yet, short-term disease control relies on the use of fungicides. The first step to reach effective management is to identify potent fungicides. In vitro experiments were conducted to determine the inhibitory concentration 50% (IC50 for mycelial growth or conidial germination, according to the chemical group of fungicides, of five Fusarium graminearum isolates of different origins. The following demethylation inhibitor (DMI fungicides were tested: epoxiconazole, cyproconazole, metconazole, prochloraz, protioconazole and tebuconazole. In addition, azoxystrobin, kresoxim-methyl, pyraclostrobin and trifloxystrobin were included in the study, representing Quinone outside inhibitor fungicides (QoI, as well as a tubulin synthesis inhibitor, carbendazim and two ready mixtures, trifloxystrobin + tebuconazole or trifloxistrobin + prothioconazole. DMI's showed lower IC50 values compared to the QoI's. For the five tested isolates, in the overall mean, IC50 considering mycelial growth ranged for DMI's from 0.01 mg/L (metconazole, prochloraz and prothioconazole to 0.12 mg/L (cyproconazole and considering conidial germination for QoI's from 0.21 mg/L (azoxystrobin to 1.33 mg/L (trifloxystrobin. The IC50 for carbendazim was 0.07 mg/L. All tested isolates can be considered sensitive to the studied DMI's, although certain differences in sensitivity could be detected between the isolates originating from one same state.

  20. Gene expression profiling in liver and testis of rats to characterize the toxicity of triazole fungicides

    International Nuclear Information System (INIS)

    Tully, Douglas B.; Bao Wenjun; Goetz, Amber K.; Blystone, Chad R.; Ren, Hongzu; Schmid, Judith E.; Strader, Lillian F.; Wood, Carmen R.; Best, Deborah S.; Narotsky, Michael G.; Wolf, Douglas C.; Rockett, John C.; Dix, David J.

    2006-01-01

    Four triazole fungicides were studied using toxicogenomic techniques to identify potential mechanisms of action. Adult male Sprague-Dawley rats were dosed for 14 days by gavage with fluconazole, myclobutanil, propiconazole, or triadimefon. Following exposure, serum was collected for hormone measurements, and liver and testes were collected for histology, enzyme biochemistry, or gene expression profiling. Body and testis weights were unaffected, but liver weights were significantly increased by all four triazoles, and hepatocytes exhibited centrilobular hypertrophy. Myclobutanil exposure increased serum testosterone and decreased sperm motility, but no treatment-related testis histopathology was observed. We hypothesized that gene expression profiles would identify potential mechanisms of toxicity and used DNA microarrays and quantitative real-time PCR (qPCR) to generate profiles. Triazole fungicides are designed to inhibit fungal cytochrome P450 (CYP) 51 enzyme but can also modulate the expression and function of mammalian CYP genes and enzymes. Triazoles affected the expression of numerous CYP genes in rat liver and testis, including multiple Cyp2c and Cyp3a isoforms as well as other xenobiotic metabolizing enzyme (XME) and transporter genes. For some genes, such as Ces2 and Udpgtr2, all four triazoles had similar effects on expression, suggesting possible common mechanisms of action. Many of these CYP, XME and transporter genes are regulated by xeno-sensing nuclear receptors, and hierarchical clustering of CAR/PXR-regulated genes demonstrated the similarities of toxicogenomic responses in liver between all four triazoles and in testis between myclobutanil and triadimefon. Triazoles also affected expression of multiple genes involved in steroid hormone metabolism in the two tissues. Thus, gene expression profiles helped identify possible toxicological mechanisms of the triazole fungicides

  1. Combined effects of drought and the fungicide tebuconazole on aquatic leaf litter decomposition.

    Science.gov (United States)

    Pesce, Stéphane; Zoghlami, Olfa; Margoum, Christelle; Artigas, Joan; Chaumot, Arnaud; Foulquier, Arnaud

    2016-04-01

    Loss of biodiversity and altered ecosystem functioning are driven by the cumulative effects of multiple natural and anthropogenic stressors affecting both quantity and quality of water resources. Here we performed a 40-day laboratory microcosm experiment to assess the individual and combined effects of drought and the model fungicide tebuconazole (TBZ) on leaf litter decomposition (LLD), a fundamental biogeochemical process in freshwater ecosystems. Starting out from a worst-case scenario perspective, leaf-associated microbial communities were exposed to severe drought conditions (four 5-day drought periods alternated with 4-day immersion periods) and/or a chronic exposure to TBZ (nominal concentration of 20μgL(-1)). We assessed the direct effects of drought and fungicide on the structure (biomass, diversity) and activity (extracellular enzymatic potential) of fungal and bacterial assemblages colonizing leaves. We also investigated indirect effects on the feeding rates of the amphipod Gammarus fossarum on leaves previously exposed to drought and/or TBZ contamination. Results indicate a stronger effect of drought stress than fungicide contamination under the experimental conditions applied. Indeed, the drought stress strongly impacted microbial community structure and activities, inhibiting the LLD process and leading to cascading effects on macroinvertebrate feeding. However, despite the lack of significant effect of TBZ applied alone, the effects of drought on microbial functions (i.e., decrease in LLD and in enzymatic activities) and on Gammarus feeding rates were more pronounced when drought and TBZ stresses were applied together. In a perspective of ecological risk assessment and ecosystem management for sustainability, these findings stress the need for deeper insight into how multiple stressors can affect the functioning of aquatic ecosystems and associated services. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Discovery of 5-substituted pyrrolo[2,3-d]pyrimidine antifolates as dual acting inhibitors of glycinamide ribonucleotide formyltransferase and 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase in de novo purine nucleotide biosynthesis: implications of inhibiting 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase to AMPK activation and anti-tumor activity

    Science.gov (United States)

    Raghavan, Sudhir; Ravindra, Manasa Punaha; Hales, Eric; Orr, Steven; Cherian, Christina; Hou, Zhanjun

    2014-01-01

    We synthesized 5-substituted pyrrolo[2,3-d]pyrimidine antifolates (compounds 5–10) with 1 to 6 bridge carbons and a benozyl ring in the side chain as antitumor agents. Compound 8 with a 4-carbon bridge was the most active analog and potently inhibited proliferation of folate receptor (FR) α-expressing Chinese hamster ovary and KB human tumor cells. Growth inhibition was reversed completely or in part by excess folic acid, indicating that FRα is involved in cellular uptake, and resulted in S-phase accumulation and apoptosis. Anti-proliferative effects of compound 8 toward KB cells were protected by excess adenosine but not thymidine, establishing de novo purine nucleotide biosynthesis as the targeted pathway. However, 5-aminoimidazole-4-carboxamide (AICA) protection was incomplete, suggesting inhibition of both AICA ribonucleotide formyltransferase (AICARFTase) and glycinamide ribonucleotide formyltransferase (GARFTase). Inhibition of GARFTase and AICARFTase by compound 8 was confirmed by cellular metabolic assays and resulted in ATP pool depletion. To our knowledge, this is the first example of an antifolate that acts as a dual inhibitor of GARFTase and AICARFTase as its principal mechanism of action. PMID:24256410

  3. Nanosulfur: A Potent Fungicide Against Food Pathogen, Aspergillus niger

    Science.gov (United States)

    Choudhury, Samrat Roy; Nair, Kishore K.; Kumar, Rajesh; Gogoi, Robin; Srivastava, Chitra; Gopal, Madhuban; Subhramanyam, B. S.; devakumar, C.; Goswami, Arunava

    2010-10-01

    Elemental sulfur (S0), man's oldest eco-friendly fungicide for curing fungal infections in plants and animals, is registered in India as a non-systemic and contact fungicide. However due to its high volume requirement, Indian agrochemical industry and farmers could not effectively use this product till date. We hypothesize that intelligent nanoscience applications might increase the visibility of nanosulfur in Indian agriculture as a potent and eco-safe fungicide. Sulfur nanoparticles (NPs) were synthesized bottom-up via a liquid synthesis method with average particle size in the range of 50-80 nm and the shapes of the NPs were spherical. A comparative study of elemental and nano-sulfur produced has been tested against facultative fungal food pathogen, Aspergillus niger. Results showed that nanosulfur is more efficacious than its elemental form.

  4. Nanosulfur: A Potent Fungicide Against Food Pathogen, Aspergillus niger

    International Nuclear Information System (INIS)

    Choudhury, Samrat Roy; Goswami, Arunava; Nair, Kishore K.; Kumar, Rajesh; Gopal, Madhuban; Devakumar, C.; Gogoi, Robin; Srivastava, Chitra; Subhramanyam, B. S.

    2010-01-01

    Elemental sulfur (S 0 ), man's oldest eco-friendly fungicide for curing fungal infections in plants and animals, is registered in India as a non-systemic and contact fungicide. However due to its high volume requirement, Indian agrochemical industry and farmers could not effectively use this product till date. We hypothesize that intelligent nanoscience applications might increase the visibility of nanosulfur in Indian agriculture as a potent and eco-safe fungicide. Sulfur nanoparticles (NPs) were synthesized bottom-up via a liquid synthesis method with average particle size in the range of 50-80 nm and the shapes of the NPs were spherical. A comparative study of elemental and nano-sulfur produced has been tested against facultative fungal food pathogen, Aspergillus niger. Results showed that nanosulfur is more efficacious than its elemental form.

  5. The complete genome sequence of Bacillus velezensis 9912D reveals its biocontrol mechanism as a novel commercial biological fungicide agent.

    Science.gov (United States)

    Pan, Hua-Qi; Li, Qing-Lian; Hu, Jiang-Chun

    2017-04-10

    A Bacillus sp. 9912 mutant, 9912D, was approved as a new biological fungicide agent by the Ministry of Agriculture of the People's Republic of China in 2016 owing to its excellent inhibitory effect on various plant pathogens and being environment-friendly. Here, we present the genome of 9912D with a circular chromosome having 4436 coding DNA sequences (CDSs), and a circular plasmid encoding 59 CDSs. This strain was finally designated as Bacillus velezensis based on phylogenomic analyses. Genome analysis revealed a total of 19 candidate gene clusters involved in secondary metabolite biosynthesis, including potential new type II lantibiotics. The absence of fengycin biosynthetic gene cluster is noteworthy. Our data offer insights into the genetic, biological and physiological characteristics of this strain and aid in deeper understanding of its biocontrol mechanism. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. New hosts of Myrothecium spp. in Brazil and a preliminary in vitro assay of fungicides

    Directory of Open Access Journals (Sweden)

    A.M. Quezado Duval

    2010-03-01

    Full Text Available Myrothecium roridum and M. verrucaria are two plant pathogenic species causing foliar spots in a large number of cultivated plants. This paper aims to study the causal agents of foliar spots in vegetable crops (sweet pepper, tomato and cucumber, ornamental plants (Spathiphyllum wallisii, Solidago canadensis, Anthurium andreanum, Dieffenbachia amoena and a solanaceous weed plant (Nicandra physaloides. Most of the isolates were identified as M. roridum; only the isolate 'Myr-02' from S. canadensis was identified as M. verrucaria. All the isolates were pathogenic to their original plant hosts and also to some other plants. Some fungicides were tested in vitro against an isolate of M. roridum and the mycelial growth recorded after seven days. Fungicides with quartenary ammonium, tebuconazole and copper were highly effective in inhibiting the mycelial growth of M. roridum. This paper confirms the first record of M. roridum causing leaf spots in sweet pepper, tomato, Spathiphyllum, Anthurium, Dieffenbachia and N. physaloides in Brazil. We also report M. roridum as causal agent of cucumber fruit rot and M. verrucaria as a pathogen of tango plants.

  7. New hosts of Myrothecium SPP. In brazil and a preliminary In Vitro assay of fungicides.

    Science.gov (United States)

    Quezado Duval, A M; Henz, G P; Paz-Lima, M L; Medeiros, A R; Miranda, B E C; Pfenning, L H; Reis, A

    2010-01-01

    Myrothecium roridum and M. verrucaria are two plant pathogenic species causing foliar spots in a large number of cultivated plants. This paper aims to study the causal agents of foliar spots in vegetable crops (sweet pepper, tomato, cucumber), ornamental plants (Spathiphyllum, Solidago canadensis, Anthurium, Dieffenbachia) and a solanaceous weed plant (Nicandra physalodes). Most of the isolates were identified as M. roridum; only the isolate 'Myr-02' from S. canadensis was identified as M. verrucaria. All the isolates were pathogenic to their original plant hosts and also to some other plants. Some fungicides were tested in vitro against an isolate of M. roridum and the mycelial growth recorded after seven days. Fungicides with quartenary ammonium, Tebuconzole and copper were highly effective in inhibiting the mycelial growth of M. roridum. This paper confirms the first record of M. roridum causing leaf spots in sweet pepper, tomato, Spathiphyllum, Anthurium, Dieffenbachia and N. physalodes. We also report M. roridum as causal agent of cucumber fruit rot and also M. verrucaria in tango plants.

  8. The effect of the fungicide captan on Saccharomyces cerevisiae and wine fermentation

    Directory of Open Access Journals (Sweden)

    Scariot Fernando J.

    2016-01-01

    Full Text Available Fungicides, particularly those used during grape maturation, as captan, can affect the natural yeast population of grapes, and can reach grape must affecting wine fermentation. The objective of the present work was to study the effect of captan on the viability and fermentative behavior of S. cerevisiae. S. cerevisiae (BY4741 on exponential phase was treated with captan (0 to 40 μM for different periods, and their cell viability analyzed. Cell membrane integrity, thiols concentration, and reactive oxygen species (ROS accumulation was determined. The fermentation experiments were conducted in synthetic must using wine yeast strain Y904. The results showed that under aerobic conditions, 20 μM of captan reduce 90% of yeast viability in 6 hours. Captan treated cells exhibited alteration of membrane integrity, reduction of thiol compounds and increase in intracellular ROS concentration, suggesting a necrotic and pro-oxidant activity of the fungicide. Fermentative experiments showed that concentrations above 2.5 μM captan completely inhibited fermentation, while a dose dependent fermentation delay associated with the reduction of yeast viability was detected in sub-inhibitory concentrations. Petit mutants increase was also observed. In conclusion, the captan induces yeast necrotic cell death on both aerobic and anaerobic conditions causing fermentation delay and/or sucking fermentations.

  9. Biological characteristics and resistance analysis of the novel fungicide SYP-1620 against Botrytis cinerea.

    Science.gov (United States)

    Zhang, Xiaoke; Wu, Dongxia; Duan, Yabing; Ge, Changyan; Wang, Jianxin; Zhou, Mingguo; Chen, Changjun

    2014-09-01

    SYP-1620, a quinone-outside-inhibitor (QoI), is a novel broad-spectrum fungicide. In this study, 108 isolates of Botrytis cinerea from different geographical regions in Jiangsu Province of China were characterized for baseline sensitivity to SYP-1620. The curves of baseline sensitivity were unimodal with a mean EC50 value of 0.0130±0.0109 μg/mL for mycelial growth, 0.01147±0.0062 μg/mL for spore germination, respectively. The biological characterization of SYP-1620 against B. cinerea was determined in vitro. The results indicated that SYP-1620 has a strong inhibiting effect on spore germination, mycelial growth, and respiration. The protective and curative test of SYP-1620 suggested that protective effect was better than curative either on strawberry leaves or on cucumber leaves in vivo. In addition, the biological characterization of SYP-1620-resistant mutants of B. cinerea was investigated. SYP-1620 has no cross-resistance with other types of fungicide. Compared to the sensitive isolates, the resistant mutants had lower mycelial growth and virulence but not differ in mycelial dry weight. Sequencing indicated that SYP-1620 resistance was associated with a single point mutation (G143A) in the cytochrome b gene. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Polyamine biosynthesis during germination of yeast ascospores.

    Science.gov (United States)

    Brawley, J V; Ferro, A J

    1979-01-01

    The role of the diamine putrescine during germination and outgrowth of ascospores of Saccharomyces cerevisiae was examined. Ornithine decarboxylase activity increased and declined rapidly during germination and outgrowth; peak activity was attained after the cells had proceeded through the G1 interval of the cell cycle, whereas minimal activity was present at the completion of the first cell division. alpha-Methylornithine inhibited both ornithine decarboxylase activity and the in vivo accumulation of putrescine. In the presence of alpha-methylornithireak dormancy and proceed through one cell division. Subsequent cellular growth, however, was retarded but not completely inhibited. The supplementation of Methylglyoxal bis(guanylhydrazone) to sporulation medium greatly inhibited this sexual process. These data suggest that the synthesis of putrescine is not required for the breaking of spore dormancy, but that polyamine biosynthesis may be essential for meiosis and sporulation. PMID:387744

  11. Mode of action of the phenylpyrrole fungicide fenpiclonil in Fusarium sulphureum

    NARCIS (Netherlands)

    Jespers, A.B.K.

    1994-01-01

    In the last few decades, plant disease control has become heavily dependent on fungicides. Most modem fungicides were discovered by random synthesis and empirical optimization of lead structures. In general, these fungicides have specific modes of action and meet modem enviromnental

  12. Fungicide residue identification and discrimination using a conducting polymer electronic-nose

    Science.gov (United States)

    Alphus D. Wilson

    2013-01-01

    The identification of fungicide residues on crop foliage is necessary to make periodic pest management decisions. The determination of fungicide residue identities currently is difficult and time consuming using conventional chemical analysis methods such as gas chromatography-mass spectroscopy. Different fungicide types produce unique electronic aroma signature...

  13. Abnormal Ergosterol Biosynthesis Activates Transcriptional Responses to Antifungal Azoles.

    Science.gov (United States)

    Hu, Chengcheng; Zhou, Mi; Wang, Wenzhao; Sun, Xianyun; Yarden, Oded; Li, Shaojie

    2018-01-01

    Fungi transcriptionally upregulate expression of azole efflux pumps and ergosterol biosynthesis pathway genes when exposed to antifungal agents that target ergosterol biosynthesis. To date, these transcriptional responses have been shown to be dependent on the presence of the azoles and/or depletion of ergosterol. Using an inducible promoter to regulate Neurospora crassa erg11 , which encodes the major azole target, sterol 14α-demethylase, we were able to demonstrate that the CDR4 azole efflux pump can be transcriptionally activated by ergosterol biosynthesis inhibition even in the absence of azoles. By analyzing ergosterol deficient mutants, we demonstrate that the transcriptional responses by cdr4 and, unexpectedly, genes encoding ergosterol biosynthesis enzymes ( erg genes) that are responsive to azoles, are not dependent on ergosterol depletion. Nonetheless, deletion of erg2 , which encodes C-8 sterol isomerase, also induced expression of cdr4 . Deletion of erg2 also induced the expression of erg24 , the gene encoding C-14 sterol reductase, but not other tested erg genes which were responsive to erg11 inactivation. This indicates that inhibition of specific steps of ergosterol biosynthesis can result in different transcriptional responses, which is further supported by our results obtained using different ergosterol biosynthesis inhibitors. Together with the sterol profiles, these results suggest that the transcriptional responses by cdr4 and erg genes are associated with accumulation of specific sterol intermediate(s). This was further supported by the fact that when the erg2 mutant was treated with ketoconazole, upstream inhibition overrode the effects by downstream inhibition on ergosterol biosynthesis pathway. Even though cdr4 expression is associated with the accumulation of sterol intermediates, intra- and extracellular sterol analysis by HPLC-MS indicated that the transcriptional induction of cdr4 did not result in efflux of the accumulated intermediate

  14. Isoprenoid Biosynthesis Inhibitors Targeting Bacterial Cell Growth.

    Science.gov (United States)

    Desai, Janish; Wang, Yang; Wang, Ke; Malwal, Satish R; Oldfield, Eric

    2016-10-06

    We synthesized potential inhibitors of farnesyl diphosphate synthase (FPPS), undecaprenyl diphosphate synthase (UPPS), or undecaprenyl diphosphate phosphatase (UPPP), and tested them in bacterial cell growth and enzyme inhibition assays. The most active compounds were found to be bisphosphonates with electron-withdrawing aryl-alkyl side chains which inhibited the growth of Gram-negative bacteria (Acinetobacter baumannii, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa) at ∼1-4 μg mL -1 levels. They were found to be potent inhibitors of FPPS; cell growth was partially "rescued" by the addition of farnesol or overexpression of FPPS, and there was synergistic activity with known isoprenoid biosynthesis pathway inhibitors. Lipophilic hydroxyalkyl phosphonic acids inhibited UPPS and UPPP at micromolar levels; they were active (∼2-6 μg mL -1 ) against Gram-positive but not Gram-negative organisms, and again exhibited synergistic activity with cell wall biosynthesis inhibitors, but only indifferent effects with other inhibitors. The results are of interest because they describe novel inhibitors of FPPS, UPPS, and UPPP with cell growth inhibitory activities as low as ∼1-2 μg mL -1 . © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Assessing the Risk for Resistance and Elucidating the Genetics of Colletotrichum truncatum That Is Only Sensitive to Some DMI Fungicides

    Directory of Open Access Journals (Sweden)

    Can Zhang

    2017-09-01

    Full Text Available The genus Colletotrichum contains a wide variety of important plant pathogens, and Colletotrichum truncatum is one of the most prevalent species of Colletotrichum on chili in China. Demethylation-inhibitor fungicides (DMIs are currently registered chemical agents for the management of the anthracnose disease caused by Colletotrichum spp. To assess the risk for DMI resistance development, 112 C. truncatum isolates were collected from infected pepper in 13 regions of China. The sensitivity of C. truncatum isolates to five DMI fungicides was determined based on mycelial growth inhibition assay. C. truncatum was sensitive to prochloraz, epoxiconazole, and difenoconazole, but not to tebuconazole or myclobutanil. Baseline sensitivity using the 112 C. truncatum isolates was established for the first three effective DMIs. Prochloraz, epoxiconazole, and difenoconazole EC50 values were 0.053 ± 0.023, 1.956 ± 0.815, and 1.027 ± 0.644 μg/ml, respectively. Eleven stable DMI-resistant mutants all exhibited lower fitness levels than their wild-type parents, suggesting a low risk of DMI resistance in C. truncatum. By inducing gene expression, CtCYP51 expression increased slightly in the resistant mutants as compared to wild-types when exposed to DMI fungicides and thus contributed at least partially to resistance. Molecular docking with CYP51 structure models was used to explain differential sensitivity of the DMI fungicides in C. truncatum. Our results suggest that the M376L/H373N mutations in CYP51 changed the conformation of DMIs in the binding pocket. These changes prevented the formation of the Fe – N coordinate bond between the heme iron active site and tebuconazole or myclobutanil, and apparently contributed to tebuconazole and myclobutanil insensitivity of C. truncatum.

  16. Assessing the Risk for Resistance and Elucidating the Genetics of Colletotrichum truncatum That Is Only Sensitive to Some DMI Fungicides

    Science.gov (United States)

    Zhang, Can; Diao, Yongzhao; Wang, Weizhen; Hao, Jianjun; Imran, Muhammad; Duan, Hongxia; Liu, Xili

    2017-01-01

    The genus Colletotrichum contains a wide variety of important plant pathogens, and Colletotrichum truncatum is one of the most prevalent species of Colletotrichum on chili in China. Demethylation-inhibitor fungicides (DMIs) are currently registered chemical agents for the management of the anthracnose disease caused by Colletotrichum spp. To assess the risk for DMI resistance development, 112 C. truncatum isolates were collected from infected pepper in 13 regions of China. The sensitivity of C. truncatum isolates to five DMI fungicides was determined based on mycelial growth inhibition assay. C. truncatum was sensitive to prochloraz, epoxiconazole, and difenoconazole, but not to tebuconazole or myclobutanil. Baseline sensitivity using the 112 C. truncatum isolates was established for the first three effective DMIs. Prochloraz, epoxiconazole, and difenoconazole EC50 values were 0.053 ± 0.023, 1.956 ± 0.815, and 1.027 ± 0.644 μg/ml, respectively. Eleven stable DMI-resistant mutants all exhibited lower fitness levels than their wild-type parents, suggesting a low risk of DMI resistance in C. truncatum. By inducing gene expression, CtCYP51 expression increased slightly in the resistant mutants as compared to wild-types when exposed to DMI fungicides and thus contributed at least partially to resistance. Molecular docking with CYP51 structure models was used to explain differential sensitivity of the DMI fungicides in C. truncatum. Our results suggest that the M376L/H373N mutations in CYP51 changed the conformation of DMIs in the binding pocket. These changes prevented the formation of the Fe – N coordinate bond between the heme iron active site and tebuconazole or myclobutanil, and apparently contributed to tebuconazole and myclobutanil insensitivity of C. truncatum. PMID:28970822

  17. impact of fungicide applications for late blight management on ...

    African Journals Online (AJOL)

    IMPACT OF FUNGICIDE APPLICATIONS FOR LATE BLIGHT. MANAGEMENT ON HUCKLEBERRY YIELDS IN CAMEROON. D. A. FONTEM, A.T. SONGWALANG, J.E. BERINYUY and R.R. SCHIPPERS l. Faculty of Agriculture, University of Dschang, Box 208, Dschang, Cameroon l~orticultural Development Services LLP, ...

  18. Field evaluatin of seed-dressing fungicides bavistin,benlate ...

    African Journals Online (AJOL)

    Field evaluatin of seed-dressing fungicides bavistin,benlate, Fernasan-D and apron plus 50 Ds for the control of seed-borne pathogens of rice ( Oryzae Saliva L ) associated with the three varieties faro 12, faro 15 and faro 29 of rice.

  19. Detoxification of copper fungicide using EDTA-modified cellulosic ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-02-04

    Feb 4, 2009 ... detoxification of a copper fungicide (KOCIDE 101) using maize cob, a cellulosic material, was studied. Based on copper as the active agent (after a ... Made from CuSO4 and lime. Used as a spray. Copper oxychloride ..... feasible when there is contact between the maize cob and the Cu(II) ions. Therefore ...

  20. Fungicidal and bactericidal properties of bisabolol and dragosantol

    Science.gov (United States)

    a-bisabolol, a natural plant sesquiterpene alcohol, and dragosantol, a racemic mixture of synthetic bisabolol, were studied for their fungicidal properties separately against the nongerminated and germinating conidia of several species of Aspergillus and Fusarium which are problems in agriculture an...

  1. Comparison of three fungicide spray advisories for lettuce downy mildew

    NARCIS (Netherlands)

    Wu, B.M.; Subbarao, K.V.; Bruggen, van A.H.C.; Koike, S.T.

    2001-01-01

    Lettuce growers in coastal California have relied mainly on protective fungicide sprays to control downy mildew. Thus, timing of sprays before infection is critical for optimal results. A leaf-wetness-driven, infection-based advisory system, previously developed, did not always perform

  2. 14C-labeling of a novel fungicide

    International Nuclear Information System (INIS)

    Nakatsuka, Iwao; Kanamaru, Hiroshi; Kamada, Takeshi; Kawahara, Kazuo; Yoshitake, Akira

    1986-01-01

    A novel fungicide, (-) (E)-1-(2,4-dichlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (S-3308 L) and its three optically active stereoisomers were labeled with carbon-14 at the triazole ring for use in the metabolic and environmental fate studies. (author)

  3. impact of fungicide applications for late blight management on ...

    African Journals Online (AJOL)

    budgeting. Benefit-cost ratio, defined as the number of times the fungicide control cost was recouped from the value for the increased yield, was calculated as: ... sub-plots. Analysis of variance (ANOVA) unsprayed sub-plots. Analysis of variance revealed highly significant (P < 0.001) differences (ANOVA) revealed highly ...

  4. Effects of phosphorus fertilization and seed dressing fungicide on ...

    African Journals Online (AJOL)

    Study on the effect of phosphorus fertilization and seed dressing fungicide on occurrence of pea aphid, Acyrthosiphon pisum and yield of lentil was conducted at Debre Zeit and Chefe Donsa for six consecutive years. Lentil genotypes Alemaya and ILL-7664 were sown at the rate of 60kg/ha on 2m wide and 4m long plots.

  5. Effect of benzimidazole fungicides and calcium chloride on ...

    African Journals Online (AJOL)

    SERVER

    2007-06-04

    Jun 4, 2007 ... Botrytis cinerea (Besri and Diatta, 1985; Hmouni et al.,. 1996). It is very likely that the repetitive uses of these systemic fungicides and their persistence during long periods of conservation (Ben Arie, 1975; Prusky, 1985) have led to considerable selective pressure on both species. Moreover, the single site ...

  6. Evaluation studies of some medicinal plant extracts and fungicides ...

    African Journals Online (AJOL)

    Evaluation studies of some medicinal plant extracts and fungicides against Alternaria solani. S Phalisteen, S Ishaq, K Amardeep, J Arif, S Sami. Abstract. Alternaria is a polyphagus fungus that occurs frequently on dead and decaying organic material and is responsible for causing leaf spot disease. In Indian subcontinent ...

  7. Sensitivity of Botrytis cinerea isolates against some fungicides used ...

    African Journals Online (AJOL)

    During August 2004 and 2005, isolates of Botrytis cinerea were collected from table and wine grapes in the Trakya region, Turkey. They were tested for sensitivity to cyprodinil+fludioxonil, fenhexamid, procymidone, pyrimethanil and tebuconazole under laboratory conditions. Fungicide sensitivity tests showed that B. cinerea ...

  8. Biological activity of triazole fungicides towards Botrytis cinerea

    NARCIS (Netherlands)

    Stehmann, C.

    1995-01-01

    Botrytis cinerea Pers. ex Fr., the causal agent of grey mould, is one of the most ubiquitous plant pathogens. The fungus is of high economic importance in various major crops and during transport and storage of agricultural products. Protectant fungicides such as

  9. Effects of Variety and Fungicidal Rate on Cercospora Leaf Spots ...

    African Journals Online (AJOL)

    A field study was carried out at the University of Maiduguri Teaching and Research Farm during the 2006, 2007 and 2008 cropping seasons to evaluate the effects of variety and fungicidal rate on Cercospora leaf spot disease of groundnut. The experimental design used was Randomized Complete Block Design (RCBD) ...

  10. Analysis of the mutations inducedd by conazole fungicides in vivo

    Science.gov (United States)

    The mouse liver tumorigenic conazo1e fungicides triadimefon and propiconazo1e have previously been shown to be in vivo mouse liver mutagens in the Big Blue" transgenic mutation assay when administered in feed at tumorigenic doses, whereas the nontumorigenic conazo1e myc1obutani1 ...

  11. Fungicide, antibiotic, heavy metal resistance and salt tolerance of ...

    African Journals Online (AJOL)

    user

    2011-03-28

    Mar 28, 2011 ... All of the rhizobial isolates showed resistance to the antibiotic (µg ml-1); streptomycin sulphate ... Using fungicides for crop diseases control in legume fields has contributed to increasing yield ..... on growth of Rhizobium japonicum and symbiotically grown soybean in soil under laboratory conditions. Prot.

  12. Studies on the response of soil microflora to the application of the fungicide fenhexamid

    DEFF Research Database (Denmark)

    El Azhari, Najoi

    2007-01-01

    The aim of this work was to evaluate the impact of the fungicide fenhexamid (FEX) on the genetic structure of soil bacterial communities using the Ribosomal Intergenic Spacer Analysis molecular technique. Using real-time PCR, we also tried to quantify the pcaH sequences which encode...... the dioxygenases involved in the degradation process of a variety of aromatic compounds. Soil taken from a vineyard in the Etna Park (Sicily, Italy) was treated with FEX in the ratio 2 µg g-1 soil every 7 days, the process being repeated four times. The analyses were carried out before treatment and 7 days after...... each further application of FEX. At the same time, the degradation rate was evaluated. The use of FEX determined a variation in the bacterial component of the soil which could be seen in an increase of some microbial strains and the inhibition of others. The pcaH sequence was already present...

  13. Synthesis and Fungicidal Activity of β-Carboline Alkaloids and Their Derivatives

    Directory of Open Access Journals (Sweden)

    Zhibin Li

    2015-07-01

    Full Text Available A series of β-Carboline derivatives were designed, synthesized, and evaluated for their fungicidal activities in this study. Several derivatives electively exhibited fungicidal activities against some fungi. Especially, compound F5 exhibited higher fungicidal activity against Rhizoctonia solani (53.35% than commercial antiviral agent validamycin (36.4%; compound F16 exhibited high fungicidal activity against Oospora citriaurantii ex Persoon (43.28%. Some of the alkaloids and their derivatives (compounds F4 and F25 exhibited broad-spectrum fungicidal activity. Specifically, compound F4 exhibited excellent high broad-spectrum fungicidal activity in vitro, and the curative and protection activities against P. litchi in vivo reached 92.59% and 59.26%, respectively. The new derivative, F4, with optimized physicochemical properties, obviously exhibited higher activities both in vitro and in vivo; therefore, F4 may be used as a new lead structure for the development of fungicidal drugs.

  14. [Optimization of oxytetracycline biosynthesis].

    Science.gov (United States)

    Maksimova, E A; Falkov, N N; Izmaĭlov, N N; Romanchuk, N N

    1988-06-01

    It was shown that rising of temperature up to 30 degrees C at the stage of the oxytetracycline-producing organism growth promoted acceleration of the culture growth rate and increasing of the antibiotic concentration by the 114th hour of the biosynthetic process. For the apparatus used in the study optimal aeration and agitation conditions were developed. To provide optimal parameters during biosynthesis of oxytetracycline, it was recommended to use the aeration rate of 1 v/v.min and the specific mechanical power for mixing of not less than 1 kW/m3.

  15. Biosynthesis of Rishirilide B

    Directory of Open Access Journals (Sweden)

    Philipp Schwarzer

    2018-03-01

    Full Text Available Rishirilide B was isolated from Streptomyces rishiriensis and Streptomyces bottropensis on the basis of its inhibitory activity towards alpha-2-macroglobulin. The biosynthesis of rishirilide B was investigated by feeding experiments with different 13C labelled precursors using the heterologous host Streptomyces albus J1074::cos4 containing a cosmid encoding of the gene cluster responsible for rishirilide B production. NMR spectroscopic analysis of labelled compounds demonstrate that the tricyclic backbone of rishirilide B is a polyketide synthesized from nine acetate units. One of the acetate units is decarboxylated to give a methyl group. The origin of the starter unit was determined to be isobutyrate.

  16. Impact of non-selective fungicides on the growth and production of ochratoxin A by Aspergillus ochraceus and A. carbonarius in barley-based medium.

    Science.gov (United States)

    Mateo, Eva M; Valle-Algarra, F M; Mateo-Castro, R; Jimenez, M

    2011-01-01

    The aim of this study was to assess the influence of the non-selective fungicides mancozeb, copper oxychloride, and sulfur on the growth and capability for producing ochratoxin A (OTA) of ochratoxigenic isolates of Aspergillus carbonarius and A. ochraceus in barley-based medium. Lag phases and growth rates were determined for each fungicide at different doses, at 15°C and 25°C and at 0.97 a(w). Mancozeb at 40 mg l(-1 )inhibited fungal growth and provided lag phases >24 days at 10-20 mg l(-1) and 15°C. OTA was observed only at 25°C and doses Sulfur was inhibitory or provided large lag phases at 5-8 g l(-1) (at 15°C) while at 25°C growth took place even at 8 g l(-1), although OTA levels were low or undetectable. The antifungal activity decreased in the order mancozeb > copper oxychloride > sulfur, and was lower at 25°C than at 15°C. OTA accumulation was affected by the type of fungicide, dose, temperature and time. The efficacy of these fungicides on the growth of A. carbonarius and A. ochraceus and OTA production in barley-based medium is assessed for the first time.

  17. The fungicidal and phytotoxic properties of benomyl and PPM in supplemented agar media supporting transgenic arabidopsis plants for a Space Shuttle flight experiment

    Science.gov (United States)

    Paul, A. L.; Semer, C.; Kucharek, T.; Ferl, R. J.

    2001-01-01

    Fungal contamination is a significant problem in the use of sucrose-enriched agar-based media for plant culture, especially in closed habitats such as the Space Shuttle. While a variety of fungicides are commercially available, not all are equal in their effectiveness in inhibiting fungal contamination. In addition, fungicide effectiveness must be weighed against its phytotoxicity and in this case, its influence on transgene expression. In a series of experiments designed to optimize media composition for a recent shuttle mission, the fungicide benomyl and the biocide "Plant Preservative Mixture" (PPM) were evaluated for effectiveness in controlling three common fungal contaminants, as well as their impact on the growth and development of arabidopsis seedlings. Benomyl proved to be an effective inhibitor of all three contaminants in concentrations as low as 2 ppm (parts per million) within the agar medium, and no evidence of phytotoxicity was observed until concentrations exceeded 20 ppm. The biocide mix PPM was effective as a fungicide only at concentrations that had deleterious effects on arabidopsis seedlings. As a result of these findings, a concentration of 3 ppm benomyl was used in the media for experiment PGIM-01 which flew on shuttle Columbia mission STS-93 in July 1999.

  18. Leaching of two fungicides in spent mushroom substrate amended soil: Influence of amendment rate, fungicide ageing and flow condition.

    Science.gov (United States)

    Álvarez-Martín, Alba; Sánchez-Martín, María J; Ordax, José M; Marín-Benito, Jesús M; Sonia Rodríguez-Cruz, M

    2017-04-15

    A study has been conducted on the leaching of two fungicides, tebuconazole and cymoxanil, in a soil amended with spent mushroom substrate (SMS), with an evaluation of how different factors influence this process. The objective was based on the potential use of SMS as a biosorbent for immobilizing pesticides in vulnerable soils, and the need to know how it could affect the subsequent transport of these retained compounds. Breakthrough curves (BTCs) for 14 C-fungicides, non-incubated and incubated over 30days, were obtained in columns packed with an unamended soil (S), and this soil amended with SMS at rates of 5% (S+SMS5) and 50% (S+SMS50) under saturated and saturated-unsaturated flows. The highest leaching of tebuconazole (>50% of the total 14 C added) was found in S when a saturated water flow was applied to the column, but the percentage of leached fungicide decreased when a saturated-unsaturated flow was applied in both SMS-amended soils. Also a significant decrease in leaching was observed for tebuconazole after incubation in the column, especially in S+SMS50 when both flows were applied. Furthermore, cymoxanil leaching was complete in S and S+SMS when a saturated flow was applied, and maximum peak concentrations were reached at 1pore volume (PV), although BTCs showed peaks with lower concentrations in S+SMS. The amounts of cymoxanil retained only increased in S+SMS when a saturated-unsaturated flow was applied. A more relevant effect of SMS for reducing the leaching of fungicide was observed when cymoxanil was previously incubated in the column, although mineralization was enhanced in this case. These results are of interest for extending SMS application on the control of the leaching of fungicides with different physicochemical characteristics after different ageing times in the soil and water flow conditions applied. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. (+)-Germacrene A Biosynthesis

    Science.gov (United States)

    de Kraker, Jan-Willem; Franssen, Maurice C.R.; de Groot, Aede; König, Wilfried A.; Bouwmeester, Harro J.

    1998-01-01

    The leaves and especially the roots of chicory (Cichorium intybus L.) contain high concentrations of bitter sesquiterpene lactones such as the guianolides lactupicrin, lactucin, and 8-deoxylactucin. Eudesmanolides and germacranolides are present in smaller amounts. Their postulated biosynthesis through the mevalonate-farnesyl diphosphate-germacradiene pathway has now been confirmed by the isolation of a (+)-germacrene A synthase from chicory roots. This sesquiterpene cyclase was purified 200-fold using a combination of anion-exchange and dye-ligand chromatography. It has a Km value of 6.6 μm, an estimated molecular mass of 54 kD, and a (broad) pH optimum around 6.7. Germacrene A, the enzymatic product, proved to be much more stable than reported in literature. Its heat-induced Cope rearrangement into (−)-β-elemene was utilized to determine its absolute configuration on an enantioselective gas chromatography column. To our knowledge, until now in sesquiterpene biosynthesis, germacrene A has only been reported as an (postulated) enzyme-bound intermediate, which, instead of being released, is subjected to additional cyclization(s) by the same enzyme that generated it from farnesyl diphosphate. However, in chicory germacrene A is released from the sesquiterpene cyclase. Apparently, subsequent oxidations and/or glucosylation of the germacrane skeleton, together with a germacrene cyclase, determine whether guaiane- or eudesmane-type sesquiterpene lactones are produced. PMID:9701594

  20. Fungicidal PMMA-Undecylenic Acid Composites.

    Science.gov (United States)

    Petrović, Milica; Bonvin, Debora; Hofmann, Heinrich; Mionić Ebersold, Marijana

    2018-01-08

    Undecylenic acid (UA), known as antifungal agent, still cannot be used to efficiently modify commercial dental materials in such a way that this affects Candida . Actually, issues with Candida infections and fungal resistance compromise the use of Poly(methyl-methacrylate) (PMMA) as dental material. The challenge remains to turn PMMA into an antifugal material, which can ideally affect both sessile (attached) and planktonic (free-floating) Candida cells. We aimed to tackle this challenge by designing PMMA-UA composites with different UA concentrations (3-12%). We studied their physico-chemical properties, the antifungal effect on Candida and the cytotoxicity toward human cells. We found that UA changes the PMMA surface into a more hydrophilic one. Mainly, as-preparation composites with ≥6% UA reduced sessile Candida for >90%. After six days, the composites were still efficiently reducing the sessile Candida cells (for ~70% for composites with ≥6% UA). Similar results were recorded for planktonic Candida . Moreover, the inhibition zone increased along with the UA concentration. The antifungal effect of UA was also examined at the surface of an UA-loaded agar and the minimal inhibitory concentration (MIC90) was below the lowest-studied 0.0125% UA. Furthermore, the embedded filamentation test after 24 h and 48 h showed complete inhibition of the Candida growth at 0.4% UA.

  1. Fungicidal PMMA-Undecylenic Acid Composites

    Directory of Open Access Journals (Sweden)

    Milica Petrović

    2018-01-01

    Full Text Available Undecylenic acid (UA, known as antifungal agent, still cannot be used to efficiently modify commercial dental materials in such a way that this affects Candida. Actually, issues with Candida infections and fungal resistance compromise the use of Poly(methyl-methacrylate (PMMA as dental material. The challenge remains to turn PMMA into an antifugal material, which can ideally affect both sessile (attached and planktonic (free-floating Candida cells. We aimed to tackle this challenge by designing PMMA-UA composites with different UA concentrations (3–12%. We studied their physico-chemical properties, the antifungal effect on Candida and the cytotoxicity toward human cells. We found that UA changes the PMMA surface into a more hydrophilic one. Mainly, as-preparation composites with ≥6% UA reduced sessile Candida for >90%. After six days, the composites were still efficiently reducing the sessile Candida cells (for ~70% for composites with ≥6% UA. Similar results were recorded for planktonic Candida. Moreover, the inhibition zone increased along with the UA concentration. The antifungal effect of UA was also examined at the surface of an UA-loaded agar and the minimal inhibitory concentration (MIC90 was below the lowest-studied 0.0125% UA. Furthermore, the embedded filamentation test after 24 h and 48 h showed complete inhibition of the Candida growth at 0.4% UA.

  2. Cholesterol biosynthesis in polychlorinated biphenyl-treated rats

    International Nuclear Information System (INIS)

    Kling, D.; Gamble, W.

    1982-01-01

    After administration of polychlorinated biphenly (PCB) at 0.055 (w/w) of the diet to Wistar rats for 30 days, followed by intraperitioneal injection of tritiated water, [ 14 C]mevalonate, and [ 14 C]acetate, there was a decrease in cholesterol biosynthesis in rat liver. No significant change in cholesterol formation was observed when PCB was administered at 0.01% (w/w) of the diet. In vitro inhibition of cholesterol synthesis by rat liver microsomes was observed with PCB. Squalene 2,3-oxidocyclase activity of rat liver microsomes was not significantly altered. Desmosterol delta 24 reductase activity was inhibited only at relatively high concentrations of PCB. There was increased incorporation of radioactivity into squalene and lanosterol, in vitro, in the presence of PCB. The primary inhibition of cholesterol biosynthesis appears to be at the demethylation and rearrangement reactions between lanosterol and cholesterol in the biosynthetic pathway

  3. Sensitivity of Phakopsora pachyrhizi (soybean rust) isolates to fungicides and the reduction of fungal sporulation based on fungicide and timing of application

    Science.gov (United States)

    Soybean rust is a damaging foliar fungal disease of soybean in many soybean-growing areas throughout the world. Strategies to manage soybean rust include the use of foliar fungicides. Fungicides types, the rate of product application, and the number and timing of applications are critical components...

  4. Zincophorin – biosynthesis in Streptomyces griseus and antibiotic properties

    Directory of Open Access Journals (Sweden)

    Walther, Elisabeth

    2016-11-01

    Full Text Available Zincophorin is a polyketide antibiotic that possesses potent activity against Gram-positive bacteria, including human pathogens. While a number of total syntheses of this highly functionalized natural product were reported since its initial discovery, the genetic basis for the biosynthesis of zincophorin has remained unclear. In this study, the co-linearity inherent to polyketide pathways was used to identify the zincophorin biosynthesis gene cluster in the genome of the natural producer HKI 0741. Interestingly, the same locus is fully conserved in the streptomycin-producing actinomycete IFO 13350, suggesting that the latter bacterium is also capable of zincophorin biosynthesis. Biological profiling of zincophorin revealed a dose-dependent inhibition of the Gram-positive bacterium . The antibacterial effect, however, is accompanied by cytotoxicity. Antibiotic and cytotoxic activities were completely abolished upon esterification of the carboxylic acid group in zincophorin.

  5. Inhibitors of amino acids biosynthesis as antifungal agents.

    Science.gov (United States)

    Jastrzębowska, Kamila; Gabriel, Iwona

    2015-02-01

    Fungal microorganisms, including the human pathogenic yeast and filamentous fungi, are able to synthesize all proteinogenic amino acids, including nine that are essential for humans. A number of enzymes catalyzing particular steps of human-essential amino acid biosynthesis are fungi specific. Numerous studies have shown that auxotrophic mutants of human pathogenic fungi impaired in biosynthesis of particular amino acids exhibit growth defect or at least reduced virulence under in vivo conditions. Several chemical compounds inhibiting activity of one of these enzymes exhibit good antifungal in vitro activity in minimal growth media, which is not always confirmed under in vivo conditions. This article provides a comprehensive overview of the present knowledge on pathways of amino acids biosynthesis in fungi, with a special emphasis put on enzymes catalyzing particular steps of these pathways as potential targets for antifungal chemotherapy.

  6. [Effects of fungicide chlorothalonil on soil nitrous oxide and carbon dioxide emissions].

    Science.gov (United States)

    Lang, Man; Cai, Zu-cong

    2008-12-01

    A 14 d incubation test at 60% WHC and 25 degrees C was conducted to study the effects of fungicide chlorothalonil at its application rates of 0, 5.5 mg x kg(-1) (field application rate, FR), 110 mg x kg(-1) (20FR) and 220 mg x kg(-1) (40FR) on the nitrous oxide (N2O) and carbon dioxide (CO2) emissions from acidic, neutral, and alkaline soils. The results indicated that the effects of chlorothalonil on the two gases emissions depended on its application rate and soil type. Comparing with no chlorothalonil application, the chlorothalonil at 20FR and 40FR inhibited the N2O emission from acid soil significantly, while that at FR, 20FR and 40FR stimulated the N2O emission from neutral soil, with the strongest effect at FR. Higher application rates (20FR and 40FR) of chlorothalonil inhibited the N2O emission from alkaline soil at the early stage of incubation, but stimulated it at late incubation stage. Chlorothalonil at FR had no obvious effects on the CO2 emission from test soils, but that at 20FR and 40FR promoted the CO2 emission from acid soil while inhibited it from neutral and alkaline soils significantly.

  7. Peptides of the constant region of antibodies display fungicidal activity.

    Directory of Open Access Journals (Sweden)

    Luciano Polonelli

    Full Text Available Synthetic peptides with sequences identical to fragments of the constant region of different classes (IgG, IgM, IgA of antibodies (Fc-peptides exerted a fungicidal activity in vitro against pathogenic yeasts, such as Candida albicans, Candida glabrata, Cryptococcus neoformans, and Malassezia furfur, including caspofungin and triazole resistant strains. Alanine-substituted derivatives of fungicidal Fc-peptides, tested to evaluate the critical role of each residue, displayed unaltered, increased or decreased candidacidal activity in vitro. An Fc-peptide, included in all human IgGs, displayed a therapeutic effect against experimental mucosal and systemic candidiasis in mouse models. It is intriguing to hypothesize that some Fc-peptides may influence the antifungal immune response and constitute the basis for devising new antifungal agents.

  8. Fungicide Efficacy in Peach Rusty Spot Control in Serbia

    Directory of Open Access Journals (Sweden)

    Nenad Dolovac

    2010-01-01

    Full Text Available Rusty Spot has long been known as a harmful peach disease in many parts of the world. During the past several years, rusty spot infection of the late-maturing peach cultivars (Summerset, Suncrest, Fayette and O’Henry caused significant yield losses in Serbia.Although the etiology of the disease is still unknown, there are numerous studies attempting to set a strategy for its control and recommend appropriate chemical and other peach protection methods. However, because of specific environmental conditions in Serbia, recommended protection method using repeated fungicide treatments, starting from petal fall, did not prove to be efficient and the rate of infection in some susceptible peach cultivars reached 100%. In 2003 and 2004 a field trial was conducted in order to test the efficacy of fungicides (a.i. kresoxim-methyl, flusilazole and sulfur for the efficient control of Rusty Spot epidemics. The trial was carried out under conditions of natural infection on the peach cv. Summerset at the locality of Bela Crkva, Serbia. In the ntreated control plots,high disease incidence was recorded with the percentage of affected fruit surface ranging from 33.5% in the first, up to the 35.4% in the second year of the trail. Among fungicides included in the trial, kresoxim-methyl proved to be the most efficient (90.25% in the first and 91.12% in the second year of the trial, flusilazole exhibited lower efficacy (87.28% and 80.61%, respectively while sulfur was the least efficient 82.33% and 80.30%, respectively. Determination of the most efficient fungicide for the peach rusty spot control in Serbia provides basic nformation for further investigations which will include optimization of treatment terms, as well as additional agro-technical control measures.

  9. Radioisotopes and fungicide research- present status and future prospects

    International Nuclear Information System (INIS)

    Chatrath, M.S.

    1996-01-01

    The developments in pesticides and radioisotopes fields were so near to each other that at a very early stage in this history, both became linked together and their usefulness was recognised for faster development. The purpose of this communication is to illustrate the present status these techniques in fungicide research by drawing suitable examples and also to bring out the directions in which future research will be going with the aid of these tools. 72 refs

  10. Biosynthesis and biotransformation of bile acids

    Directory of Open Access Journals (Sweden)

    Šarenac Tanja M.

    2017-01-01

    Full Text Available Bile acids are steroidal compounds, which contain 24 carbon atoms. They can be classified into two major groups: primary and secondary. The most abundant bile acids: The primary bile acids include cholic acid and chenodeoxycholic acid, while the major secondary bile acids are deoxycholic acid and litocholic acid. Bile acids are important physiological agents for intestinal absorption of nutrients and are used for biliary lipid secretion, toxic metabolites and xenobiotics. The aim of this paper is to analyze biosynthesis and biotransformation of bile acids, as preparation for practical usage in laboratory and clinical conditions. Topic: Biosynthesis and biotransformation of bile acids: The biosynthesis of bile acids is the dominant metabolic pathway for catabolism of cholesterol in humans. The classical route of biosynthesis of bile acids is embarking on the conversion of cholesterol into 7α-hydroxycholesterol using enzyme 7α-cholesterol hydroxylase (CYP7A1. This enzyme is one of the microsomal cytochrome P450 enzyme is localized exclusively in the liver. Classical road is the main road in the biosynthesis of bile acids, and its total contribution amounts to 90% for people, and 75% in mice. CYP 7A1 enzyme is considered to be sensitive to the inhibition of carbon monoxide, and the condition for the effect of NADPH, the oxygen, lecithin, and the NADPH-cytochrome P450 reductase. Bile acids are important signaling molecules and metabolic controls which activate the nuclear receptor and the G protein-coupled receptors (GPCR, a signaling lipid regulation of the liver, glucose and energy homeostasis. Also, bile acids maintain metabolic homeostasis. Biotransformation of bile acids: The conversion of cholesterol into bile acids just important for maintenance of cholesterol homeostasis, but also to prevent the accumulation of cholesterol, triglycerides and toxic metabolites as well as violations of the liver and other organs. Enterohepatic circulation of

  11. Radiotracer studies of fungicide residues in food plants

    International Nuclear Information System (INIS)

    1990-04-01

    Agricultural fungicides are chemicals used on seeds, crops and in soils throughout the growing season. Fungicide treatments may lead to various levels of chemical residues in food commodities. Primary emphasis has been placed on ethylenebisdithiocarbamates (EBDCs), an important group of agrofungicides used in preparations for spraying or dusting major crops such as apples, pears, broccoli, cabbages, egg plants, cauliflower, grapes, lettuce, peppers, celery, cucumbers and tomatoes. Treatments with EBDCs result in terminal residues containing ethylenthiourea (ETU). This is a toxicologically significant decomposition product which has attracted considerable attention in recent years due to indications of its potential goitrogenic and carcinogenic properties. In recognition of the need for a coordinated examination of ETU levels in food, particularly under tropical conditions, the program of radiotracer techniques as a tool for studying fungicide residue problems on food was initiated in 1984. In current studies, three EBDCs, maneb, zineb and mancozeb from different manufacturers in different countries were analysed. This report describes the model protocols (Annexes I, II and III) as they were set up for determination of residues in commodities and soil, using radiotracer and conventional chromatographic techniques . In the 16 papers presented in this report C 14 -labelled EBDCs are determined in plants, vegetables, and soils, before and after cooking, as a function of time and of other agricultural parameters. Refs, figs and tabs

  12. Curative and eradicant action of fungicides to control Phakopsora pachyrhizi in soybean plants

    Directory of Open Access Journals (Sweden)

    Erlei Melo Reis

    Full Text Available ABSTRACT Experiments were carried out in a growth chamber and laboratory to quantify the curative and eradicant actions of fungicides in Asian soybean rust control. The experiments were conducted with the CD 214 RR cultivar, assessing the following fungicides, separately or in association, chlorothalonil, flutriafol, cyproconazole + trifloxystrobin, epoxiconazole + pyraclostrobin, cyproconazole + azoxystrobin, and cyproconazole + picoxystrobin. The fungicides were applied at four (curative and nine days after inoculation (eradicant treatment. Treatments were evaluated according to the density of lesions and uredia/cm2, and the eradicant treatment was assessed based on the necrosis of lesions/uredia and on uredospore viability. Except for the fungicide chlorothalonil, there was curative action of latent/virtual infections by the fungicides. Penetrant fungicides that are absorbed have curative and eradicant action to soybean rust.

  13. Roles of the Skn7 response regulator in stress resistance, cell wall integrity and GA biosynthesis in Ganoderma lucidum.

    Science.gov (United States)

    Wang, Shengli; Shi, Liang; Hu, Yanru; Liu, Rui; Ren, Ang; Zhu, Jing; Zhao, Mingwen

    2018-05-01

    The transcription factor Skn7 is a highly conserved fungal protein that participates in a variety of processes, including oxidative stress adaptation, fungicide sensitivity, cell wall biosynthesis, cell cycle, and sporulation. In this study, a homologous gene of Saccharomyces cerevisiae Skn7 was cloned from Ganoderma lucidum. RNA interference (RNAi) was used to study the functions of Skn7, and the two knockdown strains Skn7i-5 and Skn7i-7 were obtained in G. lucidum. The knockdown of GlSkn7 resulted in hypersensitivity to oxidative and cell wall stresses. The concentrations of chitin and β-1,3-glucan distinctly decreased in the GlSkn7 knockdown strains compared with those of the wild type (WT). In addition, the expression of cell wall biosynthesis related genes was also significantly down-regulated and the thickness of the cell wall also significantly reduced in the GlSkn7 knockdown strains. The intracellular reactive oxygen species (ROS) content and ganoderic acids biosynthesis increased significantly in the GlSkn7 knockdown strains. Interestingly, the level of intracellular ROS and the content of ganoderic acids decreased after N-acetyl-L-cysteine (NAC), an ROS scavenger, was added, indicating that GlSkn7 might regulate ganoderic acids biosynthesis via the intracellular ROS level. The transcript level of GlSkn7 were up-regulated in osmotic stress, heat stress and fungicide condition. At the same time, the content of ganoderic acids in the GlSkn7 knockdown strains also changed distinctly in these conditions. Overall, GlSkn7 is involved in stress resistance, cell wall integrity and ganoderic acid biosynthesis in G. lucidum. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Dynamics of biochemical properties associated with soil nitrogen mineralization following nitrification inhibitor and fungicide applications.

    Science.gov (United States)

    Zhang, Manyun; Wang, Weijin; Wang, Jun; Teng, Ying; Xu, Zhihong

    2017-04-01

    Agrochemical applications may have side effects on soil biochemical properties related to soil nitrogen (N) mineralization and thus affect N cycling. The present study aimed to evaluate the effects of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) and fungicide iprodione on soil neutral protease (NPR), alkaline protease (APR), chitinase (CHI), and their functional genes (nprA, aprA, and chiA) related to soil N mineralization. The following four treatments were included: blank control (CK), single DMPP application (DAA), weekly iprodione applications (IPR), and the combined applications of DMPP and iprodione (DI). Compared with the CK treatment, DMPP application significantly inhibited the CHI activity in the first 14 days of incubation, and iprodione applications, particularly when applied alone, decreased the NPR, APR, and CHI activities. Relative to the IPR treatment, extra DMPP application had the potential to alleviate the inhibitory effects of iprodione on the activities of these enzymes. DMPP application significantly increased aprA gene abundances after 14 days of incubation. However, repeated iprodione applications, alone or with the DMPP, decreased nprA and chiA gene abundances. Relative to the CK treatment, DMPP application generated negligible effects on the positive/negative correlations between soil enzyme activities and the corresponding functional gene abundances. However, the positive correlation between the CHI activity and chiA gene abundance was changed to negative correlation by repeated iprodione applications, alone or together with the DMPP. Our results demonstrated that agrochemical applications, particularly repeated fungicide applications, can have inadvertent effects on enzyme activities and functional gene abundances associated with soil N mineralization.

  15. Lipophagy Contributes to Testosterone Biosynthesis in Male Rat Leydig Cells.

    Science.gov (United States)

    Ma, Yi; Zhou, Yan; Zhu, Yin-Ci; Wang, Si-Qi; Ping, Ping; Chen, Xiang-Feng

    2018-02-01

    In recent years, autophagy was found to regulate lipid metabolism through a process termed lipophagy. Lipophagy modulates the degradation of cholesteryl esters to free cholesterol (FC), which is the substrate of testosterone biosynthesis. However, the role of lipophagy in testosterone production is unknown. To investigate this, primary rat Leydig cells and varicocele rat models were administered to inhibit or promote autophagy, and testosterone, lipid droplets (LDs), total cholesterol (TC), and FC were evaluated. The results demonstrated that inhibiting autophagy in primary rat Leydig cells reduced testosterone production. Further studies demonstrated that inhibiting autophagy increased the number and size of LDs and the level of TC, but decreased the level of FC. Furthermore, hypoxia promoted autophagy in Leydig cells. We found that short-term hypoxia stimulated testosterone secretion; however, the inhibition of autophagy abolished stimulated testosterone release. Hypoxia decreased the number and size of LDs in Leydig cells, but the changes could be largely rescued by blocking autophagy. In experimental varicocele rat models, the administration of autophagy inhibitors substantially reduced serum testosterone. These data demonstrate that autophagy contributes to testosterone biosynthesis at least partially through degrading intracellular LDs/TC. Our observations might reveal an autophagic regulatory mode regarding testosterone biosynthesis. Copyright © 2018 Endocrine Society.

  16. The regulation and biosynthesis of antimycins

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    Ryan F. Seipke

    2013-11-01

    Full Text Available Antimycins (>40 members were discovered nearly 65 years ago but the discovery of the gene cluster encoding antimycin biosynthesis in 2011 has facilitated rapid progress in understanding the unusual biosynthetic pathway. Antimycin A is widely used as a piscicide in the catfish farming industry and also has potent killing activity against insects, nematodes and fungi. The mode of action of antimycins is to inhibit cytochrome c reductase in the electron transport chain and halt respiration. However, more recently, antimycin A has attracted attention as a potent and selective inhibitor of the mitochondrial anti-apoptotic proteins Bcl-2 and Bcl-xL. Remarkably, this inhibition is independent of the main mode of action of antimycins such that an artificial derivative named 2-methoxyantimycin A inhibits Bcl-xL but does not inhibit respiration. The Bcl-2/Bcl-xL family of proteins are over-produced in cancer cells that are resistant to apoptosis-inducing chemotherapy agents, so antimycins have great potential as anticancer drugs used in combination with existing chemotherapeutics. Here we review what is known about antimycins, the regulation of the ant gene cluster and the unusual biosynthetic pathway.

  17. PROCHLORAZ INHIBITS TESTOSTERONE PRODUCTION AT DOSAGE BELOW THOSE THAT AFFECT ANDROGEN-DEPENDENT ORGAN WEIGHTS OR THE ONSET OF PUBERTY IN THE MALE SPRAGUE DAWLEY RAT

    Science.gov (United States)

    ABSTRACT: Since prochloraz (PCZ) is an imidazole fungicide that inhibits gonadal steroidogenesis and antagonizes the androgen receptor (AR), we hypothesized that pubertal exposure to PCZ would delay male rat reproductive development. Sprague Dawley rats were dosed by gavage with...

  18. Phytotoxicity: An Overview of the Physiological Responses of Plants Exposed to Fungicides

    Directory of Open Access Journals (Sweden)

    Maria Celeste Dias

    2012-01-01

    Full Text Available In the last decades, the use of fungicides in agriculture for fungi diseases control has become crucial. Fungicide research has produced a diverse range of products with novel modes of action. However, the extensive use of these compounds in the agriculture system raises public concern because of the harmful potential of such substances in the environment and human health. Moreover, the phytotoxic effects of some fungicides are already recognized but little is known about the impact of these compounds on the photosynthetic apparatus. This paper presents a comprehensive overview of the literature considering different classes of fungicides and their effects on plant physiology, with particular emphasis on photosynthesis.

  19. In vivo sensitivity of Phakopsora pachyrhizi to DMI and QoI fungicides

    Directory of Open Access Journals (Sweden)

    Erlei Melo Reis

    2015-03-01

    Full Text Available In in vivo experiments the sensitivity of 18 isolates of Phakopsora pachyrhizi from several regions of Brazil to IDM fungicides (cyproconazole, epoxiconazole and tebuconazole and an IQE (pyraclostrobin were evaluated. The assessments were based on leaflet uredia density. Inhibitory concentration (IC50 and sensitivity reduction factor were determined for all fungicide x strain interactions. Tebuconazole sensitivity reduction was detected for most fungus isolates. In contrast, there was no fungicide shift in sensitivity of the fungus to pyraclostrobin. We conclude that the control failure of soybean rust found in some farms is due to the reduced sensitivity of the fungus to the IDM fungicide and that it remains sensitive to pyraclostrobin.

  20. Regulation of aromatic amino acid biosynthesis in the ribulose monophosphate cycle methylotroph Nocardia sp. 239

    NARCIS (Netherlands)

    Boer, L. de; Vrijbloed, J.W.; Grobben, G.; Dijkhuizen, L.

    The regulation of aromatic amino acid biosynthesis in Nocardia sp. 239 was studied. In cell-free extracts 3-deoxy-D-arabinoheptulosonate 7-phosphate (DAHP) synthase activity was inhibited in a cumulative manner by tryptophan, phenylalanine and tyrosine. Chorismate mutase was inhibited by both

  1. Serine biosynthesis and transport defects.

    Science.gov (United States)

    El-Hattab, Ayman W

    2016-07-01

    l-serine is a non-essential amino acid that is biosynthesized via the enzymes phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). Besides its role in protein synthesis, l-serine is a potent neurotrophic factor and a precursor of a number of essential compounds including phosphatidylserine, sphingomyelin, glycine, and d-serine. Serine biosynthesis defects result from impairments of PGDH, PSAT, or PSP leading to systemic serine deficiency. Serine biosynthesis defects present in a broad phenotypic spectrum that includes, at the severe end, Neu-Laxova syndrome, a lethal multiple congenital anomaly disease, intermediately, infantile serine biosynthesis defects with severe neurological manifestations and growth deficiency, and at the mild end, the childhood disease with intellectual disability. A serine transport defect resulting from deficiency of the ASCT1, the main transporter for serine in the central nervous system, has been recently described in children with neurological manifestations that overlap with those observed in serine biosynthesis defects. l-serine therapy may be beneficial in preventing or ameliorating symptoms in serine biosynthesis and transport defects, if started before neurological damage occurs. Herein, we review serine metabolism and transport, the clinical, biochemical, and molecular aspects of serine biosynthesis and transport defects, the mechanisms of these diseases, and the potential role of serine therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Carotenoid Biosynthesis in Fusarium

    Directory of Open Access Journals (Sweden)

    Javier Avalos

    2017-07-01

    Full Text Available Many fungi of the genus Fusarium stand out for the complexity of their secondary metabolism. Individual species may differ in their metabolic capacities, but they usually share the ability to synthesize carotenoids, a family of hydrophobic terpenoid pigments widely distributed in nature. Early studies on carotenoid biosynthesis in Fusarium aquaeductuum have been recently extended in Fusarium fujikuroi and Fusarium oxysporum, well-known biotechnological and phytopathogenic models, respectively. The major Fusarium carotenoid is neurosporaxanthin, a carboxylic xanthophyll synthesized from geranylgeranyl pyrophosphate through the activity of four enzymes, encoded by the genes carRA, carB, carT and carD. These fungi produce also minor amounts of β-carotene, which may be cleaved by the CarX oxygenase to produce retinal, the rhodopsin’s chromophore. The genes needed to produce retinal are organized in a gene cluster with a rhodopsin gene, while other carotenoid genes are not linked. In the investigated Fusarium species, the synthesis of carotenoids is induced by light through the transcriptional induction of the structural genes. In some species, deep-pigmented mutants with up-regulated expression of these genes are affected in the regulatory gene carS. The molecular mechanisms underlying the control by light and by the CarS protein are currently under investigation.

  3. Biosynthesis of Tetrahydroisoquinoline Antibiotics.

    Science.gov (United States)

    Tang, Gong-Li; Tang, Man-Cheng; Song, Li-Qiang; Zhang, Yue

    2016-01-01

    The tetrahydroisoquinoline (THIQ) alkaloids are naturally occurring antibiotics isolated from a variety of microorganisms and marine invertebrates. This family of natural products exhibit broad spectrum antimicrobial and strong antitumor activities, and the potency of clinical application has been validated by the marketing of ecteinascidin 743 (ET-743) as anticancer drug. In the past 20 years, the biosynthetic gene cluster of six THIQ antibiotics has been characterized including saframycin Mx1 from Myxococcus xanthus, safracin-B from Pseudomonas fluorescens, saframycin A, naphthyridinomycin, and quinocarcin from Streptomyces, as well as ET-743 from Ecteinascidia turbinata. This review gives a brief summary of the current status in understanding the molecular logic for the biosynthesis of these natural products, which provides new insights on the biosynthetic machinery involved in the nonribosomal peptide synthetase system. The proposal of the THIQ biosynthetic pathway not only shows nature's route to generate such complex molecules, but also set the stage to develop a different process for production of ET-743 by synthetic biology.

  4. Stereoselectivity in Polyphenol Biosynthesis

    Science.gov (United States)

    Lewis, Norman G.; Davin, Laurence B.

    1992-01-01

    Stereoselectivity plays an important role in the late stages of phenyl-propanoid metabolism, affording lignins, lignans, and neolignans. Stereoselectivity is manifested during monolignol (glucoside) synthesis, e.g., where the geometry (E or Z) of the pendant double bond affects the specificity of UDPG:coniferyl alcohol glucosyltransferases in different species. Such findings are viewed to have important ramifications in monolignol transport and storage processes, with roles for both E- and Z-monolignols and their glucosides in lignin/lignan biosynthesis being envisaged. Stereoselectivity is also of great importance in enantiose-lective enzymatic processes affording optically active lignans. Thus, cell-free extracts from Forsythia species were demonstrated to synthesize the enantiomerically pure lignans, (-)-secoisolariciresinol, and (-)-pinoresinol, when NAD(P)H, H2O2 and E-coniferyl alcohol were added. Progress toward elucidating the enzymatic steps involved in such highly stereoselective processes is discussed. Also described are preliminary studies aimed at developing methodologies to determine the subcellular location of late-stage phenylpropanoid metabolites (e.g., coniferyl alcohol) and key enzymes thereof, in intact tissue or cells. This knowledge is essential if questions regarding lignin and lignan tissue specificity and regulation of these processes are to be deciphered.

  5. Glycolipid biosynthesis in cyanobacteria

    International Nuclear Information System (INIS)

    Van Dusen, W.J.; Jaworski, J.G.

    1987-01-01

    The biosynthesis of monogalactosyldiacyl-glycerol (MGDG) was studied in five different cyanobacteria. Previous work has shown Anabaena variabilis to synthesize both MGDG and monoglucosyl-diacylglycerol (MG1cDG) with MG1cDG being the precursor of MGDG. They have examined four other cyanobacteria to determine if a similar relationship exists. The cyanobacteria studied were Anabaena variabilis, Chlorogloeopsis sp., Schizothrix calcicola, Anacystis nidulans, and Anacystis marina. Each were grown in liquid culture and lipids were labeled with 14 C]CO 2 for 20 min., 1.0 hr, 1.0 hr + 10 hr chase. Glycolipids were analyzed by initial separation of MGDG and MG1cDG by TLC followed by further analysis by HPLC. Complete separation of molecular species was obtained isocratically on an ODS column. All of the cyanobacteria labeled 16-C and 18-C fatty acids except for A. marina which labeled only 14-C and 16-C fatty acids. Desaturation of the fatty acids could be observed in the 1.0 hr and chase experiments. All were capable of labeling both MG1cDG and MGDG with the precursor-product relationship being observed. There does not appear to be a direct relationship between the epimerization of the sugar moiety and fatty acid desaturation

  6. Biosynthesis of silver nanoparticles.

    Science.gov (United States)

    Poulose, Subin; Panda, Tapobrata; Nair, Praseetha P; Théodore, Thomas

    2014-02-01

    Metal nanoparticles have unique optical, electronic, and catalytic properties. There exist well-defined physical and chemical processes for their preparation. Those processes often yield small quantities of nanoparticles having undesired morphology, and involve high temperatures for the reaction and the use of hazardous chemicals. Relatively, the older technique of bioremediation of metals uses either microorganisms or their components for the production of nanoparticles. The nanoparticles obtained from bacteria, fungi, algae, plants and their components, etc. appear environment-friendly, as toxic chemicals are not used in the processes. In addition to this, the formation of nanoparticles takes place at almost normal temperature and pressure. Control of the shape and size of the nanoparticles is possible by appropriate selection of the pH and temperature. Three important steps are the bioconversion of Ag+ ions, conversion of desired crystals to nanoparticles, and nanoparticle stability. Generally, nanoparticles are characterized by the UV-visible spectroscopy and use of the electron microscope. Silver nanoparticles are used as antimicrobial agents and they possess antifungal, anti-inflammatory, and anti-angiogenic properties. This review highlights the biosynthesis of silver nanoparticles by various organisms, possible mechanisms of their synthesis, their characterization, and applications of silver nanoparticles.

  7. Use of Cistus aqueous extracts as botanical fungicides in the control of Citrus sour rot.

    Science.gov (United States)

    Karim, H; Boubaker, H; Askarne, L; Cherifi, K; Lakhtar, H; Msanda, F; Boudyach, E H; Ait Ben Aoumar, A

    2017-03-01

    In this work, we investigated the in vitro and in vivo antifungal activity of aqueous extracts obtained from eight Cistus plant species against the development of Geotrichum citri-aurantii, the causal agent of citrus sour rot. The results demonstrate the in vitro effectiveness of all tested Cistus species aqueous extracts against G. citri-aurantii, the inhibition of mycelial growth ranged between 80 and 100%. Furthermore, Cistus aqueous extracts totally inhibited germination of G. citri-aurantii arthrospores at a concentration of 5 mg/mL. Among the plant species tested, C. laurifolius, C. salviifolius, C. monspeliensis, C. ladanifer and C. populifolius displayed the best fungistatic activity since the minimum inhibitory concentration (MIC) was extracts of C. populifolius and C. creticus compared to 100% in the control. Disease severity was lowered to 3.74, 4.47 and 5.13% when fruits were treated with C. creticus, C. ladanifer and C. populifolius aqueous extracts, respectively. Using such these biopesticides in a replacement for synthetic fungicides or in combination with other established disease management practices could help control citrus postharvest decay in a more sustainable and eco-friendly way. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Effect of seed pickling without pesticides on the growth of Penicillium expansum and patulin biosynthesis

    Directory of Open Access Journals (Sweden)

    Teresa Florianowicz

    2014-08-01

    Full Text Available The effect of seed pickling without pesticides recommended by the Research Institute of Vegetable Crops in Skierniewice in the method of intensive environment-friendly cultivation on the growth and patulin biosynthesis of patulinogenous microfungus Penicillim expansum, was investigated. A complete inhibition of patulin biosynthesis at 6% and no growth at 8% concentration of the dressing in in vitro conditions was revealed.

  9. Lipid, membrane, and mitochondrial characteristics of Ustilago maydis following exposure to ergosterol biosynthesis inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Waterfield, W.F. III

    1986-01-01

    Pencoazole at 0.5 ..mu..g/ml inhibited ergosterol biosynthesis in U. maydis. Polar lipids of sporidia grown with 0.5 ..mu..g/ml penconazole for 7.5 or 22 hr or 1.0 ..mu..g/ml fenarimol for 7.5 hr contained more 18:2 than 18:1 fatty acids. There was usually more 18:1 than 18:2 fatty acids in polar lipids of untreated sporidia but this ratio was influenced by culture cell density. The high 18:2 to 18:1 ratio in the polar lipids from penconazole grown cells was unaffected by cell density. There was an increase in free fatty acids and these were enriched with 18:2 members in cells grown with 0.5 ..mu..g/ml penconazole for 22 hr. Unsaturation of triglycerides fatty acids did not differ appreciably from that of untreated sporidia. Untreated WT U. maydis protoplasts lysed more slowly in 0.3 M sorbitol than those prepared from WT sporidia grown for 16 hr with 1.0 ..mu..g/ml penconazole or 2.0 ..mu..g/ml fenarimol or from untreated erg-40 sporidia. Protoplasts were more permeable to crystal violet than were those from untreated WT sporidia. Mitochondria from untreated WT sporidia oxidizing pyruvate plus malate or succinate yielded higher ADP/O rations than mitochondria from erg-40 or penconazole grown WT sporidia. The mitochondrial ATPase of control cells had a Km of 0.8 mM ATP whereas the mitochondrial ATPase of penconazole grown WT and erg-40 had a Km value of 3.7 and 3.2 mM ATP, respectively. When the mitochondrial catalytic subunit of the ATPase from these mitochondria were solubilized, the Km did not differ. These studies suggest that changes in sterols and membrane fatty acids resulting from treatments with EBI fungicides cause increased membrane fluidity which affects membrane stability, permeability and activity of the mitochondrial ATPase.

  10. Isoflavone formononetin from red propolis acts as a fungicide against Candida sp.

    Science.gov (United States)

    das Neves, Michelline Viviane Marques; da Silva, Tânia Maria Sarmento; Lima, Edeltrudes de Oliveira; da Cunha, Emídio Vasconcelos Leitão; Oliveira, Eduardo de Jesus

    2016-01-01

    A bioassay-guided fractionation of two samples of Brazilian red propolis (from Igarassu, PE, Brazil, hereinafter propolis 1 and 2) was conducted in order to determine the components responsible for its antimicrobial activity, especially against Candida spp. Samples of both the crude powdered resin and the crude ethanolic extract of propolis from both locations inhibited the growth of all 12 tested Candida strains, with a minimum inhibitory concentration of 256μg/mL. The hexane, acetate and methanol fractions of propolis 1 also inhibited all strains with minimum inhibitory concentration values ranging from 128 to 512μg/mL for the six bacteria tested and from 32 to 1024μg/mL for the yeasts. Similarly, hexane and acetate fractions of propolis sample 2 inhibited all microorganisms tested, with minimum inhibitory concentration values of 512μg/mL for bacteria and 32μg/mL for yeasts. The extracts were analyzed by HPLC and their phenolic profile allowed us to identify and quantitate one phenolic acid and seven flavonoids in the crude ethanolic extract. Formononetin and pinocembrin were the major constituents amongst the identified compounds. Formononetin was detected in all extracts and fractions tested, except for the methanolic fraction of sample 2. The isolated isoflavone formononetin inhibited the growth of all the microorganisms tested, with a minimum inhibitory concentration of 200μg/mL for the six bacteria strains tested and 25μg/mL for the six yeasts. Formononetin also exhibited fungicidal activity against five of the six yeasts tested. Taken together our results demonstrate that the isoflavone formononetin is implicated in the reported antimicrobial activity of red propolis. Copyright © 2015 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  11. Conversion of the fungicide, ziram in rice plants

    International Nuclear Information System (INIS)

    Kumarasamy, R.; Raghu, K.

    1976-01-01

    Zinc dimethyldithiocarbamate (ziram) is a toliar fungicide used for the control of the blast disease of rice caused by Pyricularia oryzae, and is also used for the control of the plant diseases in crops like groundnut, cotton, etc. Since there is lack of data on the conversion products of this fungicide. This investigation was carried out. The results of the author's recent studies with 35 S-labelled ziram in rice seedlings were reported. The 35 S-Labelled ziram (specific activity 1.5 m Ci/m mole) was sprayed on the rice seedlings of 25 days old. At different intervals of time, the seedlings were removed, washed thoroughly, cut into pieces, and extracted with 80% ethanol. By the method described in ''K. Raghu et al., Origin and fate of chemical residents in food, agriculture and fisheries, I.A.E.A., Vienna, 1975, pp. 137-148,'' the segments corresponding to the standards of dimethyl dithio carbamate-alanine (DDCA), DDC-glucoside (DDCG), thiazolidine-2-thione-4-carbamic acid (TTCA), unidentified divolent fungicide (X), and ziram were cut out and the radioactivity was counted in cocktail D scintillation fluid using an LS-100 Beckmann liquid scintillation counter. It is indeed interesting to note that ziram is converted in plant tissues into dimethyldithiocarbamate derivatives like DDCG, DDCA, TTCA and X within 24 hr after spraying. The amounts of these derivatives varied in the course of sampling up to 8 days after spraying. Further studies are needed as to the quantitative nature of these products, but the present report clearly demonstrates the formation of these conversion products in the rice leaves treated with ziram. (Kobatake, H.)

  12. Reduced fungicide doses in cereals: Which parameters to consider?

    DEFF Research Database (Denmark)

    Jørgensen, Lise Nistrup

    2015-01-01

    , the pathogen, disease pressure and timing of treatments. Certain diseases are known to require higher input (40- 75% rates) for achieving satisfactory control – this is the case for Septoria leaf blight, Rhynchosporium net blotch and Fusarium head blight, whereas most rust diseases generally have been found...... to be controlled successfully at rates down to quarter rates. Fungicides, in general, show highly variable dose responses for specific diseases, which is important to know when specific advice is given. Preventive treatments generally require less input compared with treatments during the latent period or later...

  13. FUNGICIDAL PROPERTIES OF ARTEMISIA AROMATIC PLANTS TOWARDS FUSARIUM OXYSPORUM

    Directory of Open Access Journals (Sweden)

    Ivashchenko Iryna Vіctorovna

    2015-08-01

    Full Text Available The article establishes the fungicidal activity of water extracts of Artemisia maritimа L., Artemisia austriaca Jacq., under the concentration of 100, 50 and 25 mg/ml on dry matter with regard to the phytopathogenic mushroom Fusarium oxysporum. It also shows the fungistatic influence of extract of Artemisia dracunculus L. under concentration 25 and 50 mg/ml, fungicidal – under 100 mg/ml. Concerning Artemisia abrotanum L., the slow growth of mushroom is observed under the concentration 25 mg/ml, fungicidal effect – under 50 and 100 mg/ml. The paper provides the information on the component composition of ethereal oil and phenolic compounds of Artemisia maritimа, Artemisia austriaca, Artemisia abrotanum, Artemisia dracunculus, cultivated in Zhytomyr Polissya. The chief ingredients of ethereal oil which is synthesized by the plant of Artemisia abrotanum are 1,8-cineole (30.44% and camphor (31.92%. A high 1,8-cineole and camphor content determines antimicrobial properties of the plants. Amount of phenolic compounds in the air-dry raw Artemisia abrotanum is 2.98 percent. By the method of highly efficient solution chromatography (HESChr in the grass of Artemisia abrotanum we have detected 23 phenolic compounds, of which we identified such flavonoids as rutin, luteolin-7-glycoside as well as caffeic, chlorogenic and isochlorogenic acids. The main compounds of ethereal oil of Artemisia austriaca are trans-verbenole (30.77 %, pinocarvone (10.77 % and sabinilacetate (18.16 %. In the grass of Artemisia austriaca we have detected 31 phenolic compounds, of which we identified such flavonoids as rutin, apigenin, quercetin-bioside and the following acids: caffeic, chlorogenic, and isochlorogenic. Amount of phenolic compounds in the air-dry raw Austrian wormwood is 27.25 mg / g (2.73 %. The main component of ethereal oil of Artemisia dracunculus is methyleugenol (94.65 %. We have discovered 31 phenolic compounds in the grass of linear-leaved wormwood

  14. An evaluation of some fungicides in the management of fruit and leaf ...

    African Journals Online (AJOL)

    Four fungicide treatments viz Ben late (Benomyl), Cupravit (Copper oxychloride), Dithane M45 (Mancozeb), and Ben late alternated with Dithane M45 were applied to control Phaeoramularia angolensis in a block of the variety "Valencia" in the citrus orchard at Kiige, Uganda. No fungicide was applied to the control. Benlate ...

  15. Efficacy and economics of fungicide spray in the control of late blight ...

    African Journals Online (AJOL)

    The chemical control started immediately after the first disease symptom was observed (41days after crop emergence) and chemical control was repeated after every 7 days for contact fungicides and 21 days for preventive fungicide. In 1997 AL-624 and Tolcha received 4 -5 and 2 applications, respectively, of the protectant ...

  16. Fungicidal effect of 15 disinfectants against 24 fungal contaminants commonly found in bread and cheese manufacturing

    DEFF Research Database (Denmark)

    Bundgaard-Nielsen, Kirsten; Nielsen, Per Væggemose

    1996-01-01

    .0 % formaldehyde, 0.1 % potassium hydroxide, 3.0 % hydrogen peroxide or 0.3 % peracetic acid were ineffective as fungicides. The fungicidal effect of quaternary ammonium compounds and chlorine compounds showed great variance between species and among the 6 tested isolates of Penicillium roqueforti var. roqueforti...

  17. Fungicide resistance phenotypes in Botrytis cinerea populations from blueberries in California and Washington

    Science.gov (United States)

    Gray mold caused by Botrytis cinerea is a major postharvest disease of blueberries grown in the Central Valley of California (CA) and western Washington State (WA). Understanding fungicide- resistant phenotypes of B. cinerea is important to the development of preharvest fungicide programs for contro...

  18. Effects of azole fungicides on the function of sex and thyroid hormones

    DEFF Research Database (Denmark)

    Kjærstad, Mia Birkhøj; Andersen, Helle Raun; Taxvig, Camilla

    Azole-fungicides are frequently used in Denmark. Epoxiconazole, propiconazole, and tebuconazole had endocrine disrupting properties in cell based assays. In rats, epoxiconazole and tebuconazole increased gestational length, maternal progesterone level, and masculinized female-offspring. Besides, ......, tebuconazole caused feminization of male-offspring. Similar effects were previously demonstrated for prochloraz. The results indicate that azole-fungicides in general have endocrine disrupting properties....

  19. Alleviation of fungicide-induced phytotoxicity in greengram [Vigna radiata (L.) Wilczek] using fungicide-tolerant and plant growth promoting Pseudomonas strain

    OpenAIRE

    Ahemad, Munees; Khan, Mohammad Saghir

    2012-01-01

    This study was designed to explore beneficial plant-associated rhizobacteria exhibiting substantial tolerance against fungicide tebuconazole vis-à-vis synthesizing plant growth regulators under fungicide stressed soils and to evaluate further these multifaceted rhizobacteria for protection and growth promotion of greengram [Vigna radiata (L.) Wilczek] plants against phytotoxicity of tebuconazole. Tebuconazole-tolerant and plant growth promoting bacterial strain PS1 was isolated from mustard (...

  20. Rieske iron-sulfur protein of the cytochrome bc(1) complex: a potential target for fungicide discovery.

    Science.gov (United States)

    Yang, Wen-Chao; Li, Hui; Wang, Fu; Zhu, Xiao-Lei; Yang, Guang-Fu

    2012-07-23

    The cytochrome bc(1) complex (complex III, cyt bc(1)) is an essential component of cellular respiration. Cyt bc(1) has three core subunits that are required for its catalytic activity: cytochrome b, cytochrome c(1), and the Rieske iron-sulfur protein (ISP). Although most fungicides inhibit this enzyme by binding to the cytochrome b subunit, resistance to these fungicides has developed rapidly due to their widespread application. Resistance is mainly associated with mutations in cytochrome b, the only subunit encoded by mitochondrial DNA. Recently, the flexibility and motion of the ISP and its essential role in electron transfer have received intense attention; this leads us to propose a new classification of cyt bc(1) inhibitors (three types of Q(o) inhibitors) that mobilize, restrict, or fix the rotation of the ISP. Importantly, the strengths of the ISP-inhibitor interactions correlate with inhibitor activity and the development of resistance to Q(o) inhibitors, thereby offering clues for designing novel cyt bc(1) inhibitors with high potency and a low risk of resistance. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. The low keratin affinity of efinaconazole contributes to its nail penetration and fungicidal activity in topical onychomycosis treatment.

    Science.gov (United States)

    Sugiura, Keita; Sugimoto, Noriaki; Hosaka, Shinya; Katafuchi-Nagashima, Maria; Arakawa, Yoshio; Tatsumi, Yoshiyuki; Jo Siu, William; Pillai, Radhakrishnan

    2014-07-01

    Onychomycosis is a common fungal nail disease that is difficult to treat topically due to the deep location of the infection under the densely keratinized nail plate. Keratin affinity of topical drugs is an important physicochemical property impacting therapeutic efficacy. To be effective, topical drugs must penetrate the nail bed and retain their antifungal activity within the nail matrix, both of which are adversely affected by keratin binding. We investigated these properties for efinaconazole, a new topical antifungal for onychomycosis, compared with those of the existing topical drugs ciclopirox and amorolfine. The efinaconazole free-drug concentration in keratin suspensions was 14.3%, significantly higher than the concentrations of ciclopirox and amorolfine, which were 0.7% and 1.9%, respectively (P nails into the receptor phase and also inhibited the growth of Trichophyton rubrum under the nail. In the presence of keratin, efinaconazole exhibited fungicidal activity against Trichophyton mentagrophytes comparable to that of amorolfine and superior to that of ciclopirox. In a guinea pig onychomycosis model with T. mentagrophytes infection, an efinaconazole solution significantly decreased nail fungal burden compared to that of ciclopirox and amorolfine lacquers (P nail permeability of efinaconazole and its potent fungicidal activity in the presence of keratin are related to its low keratin affinity, which may contribute to its efficacy in onychomycosis. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  2. Emerging resistance against different fungicides in Lasiodiplodia theobromae, the cause of mango dieback in Pakistan

    Directory of Open Access Journals (Sweden)

    Rehman ur Ateeq

    2015-01-01

    Full Text Available Dieback of mango caused by Lasiodiplodia theobromae is among several diseases responsible for low crop production in Pakistan. To further complicate the issue, resistance in L. theobromae is emerging against different fungicides. L. theobromae was isolated from diseased samples of mango plants collected from various orchards in the Multan District. The efficacy of different fungicides viz. copper oxychloride, diethofencarb, pyrachlostrobin, carbendazim, difenoconazole, mancozeb, and thiophanate-methyl was evaluated in vitro using a poison food technique. Thiophanate-methyl at all concentrations was found to be the most effective among five systemic fungicides against L. theobromae, followed by carbendazim, difenoconazole and diethofencarb. The fungicides, i.e., thiophanate-methyl, difenoconazole, carbendazim and diethofencarb showed maximum efficacy with increasing concentration. The isolates of L. theobromae showed some resistance development against the tested fungicides when compared with previous work. These investigations provide new information about chemical selection for the control of holistic disease in mango growing zones of Pakistan.

  3. Sustained release of fungicide metalaxyl by mesoporous silica nanospheres

    International Nuclear Information System (INIS)

    Wanyika, Harrison

    2013-01-01

    The use of nanomaterials for the controlled delivery of pesticides is nascent technology that has the potential to increase the efficiency of food production and decrease pollution. In this work, the prospect of mesoporous silica nanoparticles (MSN) for storage and controlled release of metalaxyl fungicide has been investigated. Mesoporous silica nanospheres with average particle diameters of 162 nm and average pore sizes of 3.2 nm were prepared by a sol–gel process. Metalaxyl molecules were loaded into MSN pores from an aqueous solution by a rotary evaporation method. The loaded amount of metalaxyl as evaluated by thermogravimetric analysis was about 14 wt%. Release of the fungicide entrapped in the MSN matrix revealed sustained release behavior. About 76 % of the free metalaxyl was released in soil within a period of 30 days while only 11.5 and 47 % of the metalaxyl contained in the MSN carrier was released in soil and water, respectively, within the same period. The study showed that MSN can be used to successfully store metalaxyl molecules in its mesoporous framework and significantly delay their release in soil

  4. Design, Synthesis and Fungicidal Activities of Some Novel Pyrazole Derivatives

    Directory of Open Access Journals (Sweden)

    Xue-Ru Liu

    2014-09-01

    Full Text Available In order to discover new compounds with good fungicidal activities, 32 pyrazole derivatives were designed and synthesized. The structures of the target compounds were confirmed by 1H-NMR, 13C-NMR, and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS, and their fungicidal activities against Botrytis cinerea, Rhizoctonia solani Kuhn, Valsa mali Miyabe et Yamada, Thanatephorus cucumeris (Frank Donk, Fusarium oxysporum (S-chl f.sp. cucumerinum Owen, and Fusarium graminearum Schw were tested. The bioassay results indicated that most of the derivatives exhibited considerable antifungal activities, especially compound 26 containing a p-trifluoromethyl- phenyl moiety showed the highest activity, with EC50 values of 2.432, 2.182, 1.787, 1.638, 6.986, and 6.043 μg/mL against B. cinerea, R. solani, V. mali, T. cucumeris, F. oxysporum, and F. graminearum, respectively. Moreover, the activities of compounds such as compounds 27–32 were enhanced by introducing isothiocyanate and carboxamide moieties to the 5-position of the pyrazole ring.

  5. Dipping Strawberry Plants in Fungicides before Planting to Control Anthracnose

    Directory of Open Access Journals (Sweden)

    Myeong Hyeon Nam

    2014-03-01

    Full Text Available Anthracnose crown rot (ACR, caused by Colletotrichum fructicola, is a serious disease of strawberry in Korea. The primary inoculums of ACR were symptomless strawberry plants, plant debris, and other host plants. To effectively control anthracnose in symptomless transplanted strawberries, it is necessary to use diseasefree plants, detect the disease early, and apply a fungicide. Therefore, in 2010 and 2011, we evaluated the efficacy of pre-plant fungicide dips by using strawberry transplants infected by C. fructicola for the control of anthracnose. Dipping plants in prochloraz-Mn for 10 min before planting was most effective for controlling anthracnose in symptomless strawberry plants and resulted in more than 76% control efficacy. Azoxystrobin showed a control efficacy of over 40%, but plants treated with pyraclostrobin, mancozeb and iminoctadine tris showed high disease severity. The control efficacy of the dip treatment with prochloraz-Mn did not differ with temperature and time. Treatment with prochloraz-Mn for more than an hour caused growth suppression in strawberry plants. Therefore, the development of anthracnose can be effectively reduced by dipping strawberry plants for 10 min in prochloraz-Mn before planting.

  6. FUNGICIDE APPLICATION FOR MAINTAINING POSTHARVEST QUALITY IN TOMATO FRUITS

    Directory of Open Access Journals (Sweden)

    D. M. Vani

    2014-07-01

    Full Text Available Tomato fruits are usually consumed soon after harvest, however, as they are mainly comprised of water, and its walls are fragile, facilitates the emergence of diseases, making necessary the use of preventive measures in the field in order to reduce incidence of disease. The objective is then to evaluate the effect of foliar application of fungicides on the final quality of tomato fruits in postharvest. There were 13 applications of foliar fungicides Azoxystrobin+Cyproconazol and Boscalida, 7 applications Tebuconazol+Trifoxistrobin and 17 applications of Propamocarb+Fluopicolide (Control. We analyzed the incidence of Fusarium sp. in fruits, decay percentage of fruit weight (g and Brix. For incidence of Fusarium sp. in fruits, treatments Tebuconazol+Trifoxistrobin and Azoxistrobin+Ciproconazol reduced by 14.3%, the pathogen in fruits. There was a decrease of 82% in the deterioration of fruits treated with Tebuconazol+Trifoxistrobin and 91% in those treated with Azoxistrobin+Ciproconazol. As for the weight gain, treatments Tebuconazol+Trifoxistrobin, Boscalida and Azoxistrobin+Ciproconazol reduced the weight gain in 8.12%, 20.8% and 38.8%, respectively, compared to the control. ° Brix values of fruits treated with Tebuconazol+Trifoxistrobin and Boscalida were higher than those treated with Azoxistrobin+Ciproconazol and Control (Propamocarb+Fluopicolide. It is concluded that the treatment carried out with Tebuconazol+Trifoxistrobin afforded the greatest benefits in maintaining the tomato fruits in harvest.

  7. Sustained release of fungicide metalaxyl by mesoporous silica nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Wanyika, Harrison, E-mail: hwanyika@gmail.com [Jomo Kenyatta University of Agriculture and Technology, Department of Chemistry (Kenya)

    2013-08-15

    The use of nanomaterials for the controlled delivery of pesticides is nascent technology that has the potential to increase the efficiency of food production and decrease pollution. In this work, the prospect of mesoporous silica nanoparticles (MSN) for storage and controlled release of metalaxyl fungicide has been investigated. Mesoporous silica nanospheres with average particle diameters of 162 nm and average pore sizes of 3.2 nm were prepared by a sol-gel process. Metalaxyl molecules were loaded into MSN pores from an aqueous solution by a rotary evaporation method. The loaded amount of metalaxyl as evaluated by thermogravimetric analysis was about 14 wt%. Release of the fungicide entrapped in the MSN matrix revealed sustained release behavior. About 76 % of the free metalaxyl was released in soil within a period of 30 days while only 11.5 and 47 % of the metalaxyl contained in the MSN carrier was released in soil and water, respectively, within the same period. The study showed that MSN can be used to successfully store metalaxyl molecules in its mesoporous framework and significantly delay their release in soil.

  8. Auxin biosynthesis and storage forms

    Science.gov (United States)

    Strader, Lucia C.

    2013-01-01

    The plant hormone auxin drives plant growth and morphogenesis. The levels and distribution of the active auxin indole-3-acetic acid (IAA) are tightly controlled through synthesis, inactivation, and transport. Many auxin precursors and modified auxin forms, used to regulate auxin homeostasis, have been identified; however, very little is known about the integration of multiple auxin biosynthesis and inactivation pathways. This review discusses the many ways auxin levels are regulated through biosynthesis, storage forms, and inactivation, and the potential roles modified auxins play in regulating the bioactive pool of auxin to affect plant growth and development. PMID:23580748

  9. Hypericin: chemical synthesis and biosynthesis.

    Science.gov (United States)

    Huang, Lin-Fang; Wang, Zeng-Hui; Chen, Shi-Lin

    2014-02-01

    Hypericin is one of the most important phenanthoperylene quinones extracted mainly from plants of the genus Hypericum belonging to the sections Euhypericum and Campylosporus of Keller's classification. Widespread attention to the antiviral and anti-tumor properties of hypericin has spurred investigations of the chemical synthesis and biosynthesis of this unique compound. However, the synthetic strategies are challenging for organic and biological chemists. In this review, specific significant advances in total synthesis, semi-synthesis, and biosynthesis in the past decades are summarized. Copyright © 2014 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  10. Potential effects of fungicide and algaecide extracts of Annona glabra L. (Annonaceae) on the microalgae Raphidocelis subcapitata and on the oomycete Pythium.

    Science.gov (United States)

    Rocha, Giseli S; Matsumoto, Reginaldo S; Lombardi, Ana Teresa; Lima, Maria Inês S

    2017-01-01

    Annona glabra L. is a semi-deciduous tree that contains several active substances, including secondary metabolites, with antifungal activity. Phytopathogenic strains of the genus Pythium cause billion dollar losses all over the world on natural and crop species. Searching for eco-friendly algaecides and fungicides, we analyzed the effects of acetone extracts of A. glabra leaves on the algae Rhaphidocelis subcapitata (Korshikov) and on the oomycete Pythium aphanidermatum (Edson). We evaluated ten extract concentrations for each organism - 0 to 400 mg L-1 for algae and 0-1000 µg disc1 for oomycete. The results showed no effect on algae up to 75 mg L-1, but a significant inhibitory effect at 125 mg L-1 and above, which reduced the growth rate and the final biomass of the algae. Extract concentrations above 200 mg L-1 were completely inhibitory. The half maximal inhibitory concentration for 72 and 96 h of exposure to our crude extracts are comparable to those obtained with commercial fungicides and herbicides used in aquatic ecosystems. The P. aphanidermatum inhibition concentrations have effects comparable to fungicides as Cycloheximide and Bifonazole. Some substances isolated from the extracts are described as antifungals, which could explain part of anti-oomycete activity. Our results highlight the importance of searching bioactive compounds from plants.

  11. Potential effects of fungicide and algaecide extracts of Annona glabra L. (Annonaceae on the microalgae Raphidocelis subcapitata and on the oomycete Pythium

    Directory of Open Access Journals (Sweden)

    GISELI S. ROCHA

    Full Text Available ABSTRACT Annona glabra L. is a semi-deciduous tree that contains several active substances, including secondary metabolites, with antifungal activity. Phytopathogenic strains of the genus Pythium cause billion dollar losses all over the world on natural and crop species. Searching for eco-friendly algaecides and fungicides, we analyzed the effects of acetone extracts of A. glabra leaves on the algae Rhaphidocelis subcapitata (Korshikov and on the oomycete Pythium aphanidermatum (Edson. We evaluated ten extract concentrations for each organism - 0 to 400 mg L-1 for algae and 0-1000 µg disc1 for oomycete. The results showed no effect on algae up to 75 mg L-1, but a significant inhibitory effect at 125 mg L-1 and above, which reduced the growth rate and the final biomass of the algae. Extract concentrations above 200 mg L-1 were completely inhibitory. The half maximal inhibitory concentration for 72 and 96 h of exposure to our crude extracts are comparable to those obtained with commercial fungicides and herbicides used in aquatic ecosystems. The P. aphanidermatum inhibition concentrations have effects comparable to fungicides as Cycloheximide and Bifonazole. Some substances isolated from the extracts are described as antifungals, which could explain part of anti-oomycete activity. Our results highlight the importance of searching bioactive compounds from plants.

  12. Melatonin Attenuates Potato Late Blight by Disrupting Cell Growth, Stress Tolerance, Fungicide Susceptibility and Homeostasis of Gene Expression in Phytophthora infestans

    Directory of Open Access Journals (Sweden)

    Shumin Zhang

    2017-11-01

    Full Text Available Phytophthora infestans (P. infestans is the causal agent of potato late blight, which caused the devastating Irish Potato Famine during 1845-1852. Until now, potato late blight is still the most serious threat to potato growth and has caused significant economic losses worldwide. Melatonin can induce plant innate immunity against pathogen infection, but the direct effects of melatonin on plant pathogens are poorly understood. In this study, we investigated the direct effects of melatonin on P. infestans. Exogenous melatonin significantly attenuated the potato late blight by inhibiting mycelial growth, changing cell ultrastructure, and reducing stress tolerance of P. infestans. Notably, synergistic anti-fungal effects of melatonin with fungicides on P. infestans suggest that melatonin could reduce the dose levels and enhance the efficacy of fungicide against potato late blight. A transcriptome analysis was carried out to mine downstream genes whose expression levels were affected by melatonin. The analysis of the transcriptome suggests that 66 differentially expressed genes involved in amino acid metabolic processes were significantly affected by melatonin. Moreover, the differentially expressed genes associated with stress tolerance, fungicide resistance, and virulence were also affected. These findings contribute to a new understanding of the direct functions of the melatonin on P. infestans and provide a potential ecofriendly biocontrol approach using a melatonin-based paradigm and application to prevent potato late blight.

  13. (vitamin B1) biosynthesis genes

    African Journals Online (AJOL)

    In this study, the gene transcripts of first two enzymes in thiamine biosynthesis pathway, THIC and THI1/THI4 were identified and amplified from oil palm tissues. Primers were designed based on sequence comparison of the genes from Arabidopsis thaliana, Zea mays, Oryza sativa and Alnus glutinosa. Oil palm's responses ...

  14. Preliminary evaluation of fungicidal and termiticidal activities of filtrates from biomass slurry fuel production

    Energy Technology Data Exchange (ETDEWEB)

    Kartal, S.N. [Istanbul University (Turkey). Forestry Faculty; Imamura, Y. [Kyoto University (Japan). Wood Research Institute; Tsuchiya, F.; Ohsato, K. [JGC Corporation, Yokohama (Japan)

    2004-10-01

    Biomass slurry fuel (BSF) production has recently been developed as a natural energy for the conversion of solid biomass into fuel. In addition to using fuel, filtrates from BSF production may also serve a chemical source with several organic compounds. There is an increasing interest in the research and application of biomass-based filtrates. In this study, fungicidal and termiticidal properties of filtrates from BSF production using sugi (Cryptomeria japonica) and acacia (Acacia mangium) wood were evaluated in laboratory decay and termite resistance tests. Wood blocks treated with the filtrates showed increased resistance against brown-rot fungus, Formitopsis palustris. However the filtrates from sugi wood processed at 270{sup o}C which contained less phenolic compounds than the other filtrates were effective against white-rot fungus, Trametes versicolor. Phenolic compounds of filtrates seemed to play a role in the decay resistance tests however the filtrates did not increase the durability of the wood blocks against subterranean termites Coptotermes formosanus. Despite high acetic and lactic acid content of the filtrates, vanillin content of the filtrates may have served as an additional food source and promoted termite attack. It can be concluded that filtrates with phenolic compounds from lignin degradation during BSF production can be considered for targeted inhibition of brown-rot. (author)

  15. Microcolony imaging of Aspergillus fumigatus treated with echinocandins reveals both fungistatic and fungicidal activities.

    Directory of Open Access Journals (Sweden)

    Colin J Ingham

    Full Text Available BACKGROUND: The echinocandins are lipopeptides that can be employed as antifungal drugs that inhibit the synthesis of 1,3-β-glucans within the fungal cell wall. Anidulafungin and caspofungin are echinocandins used in the treatment of Candida infections and have activity against other fungi including Aspergillus fumigatus. The echinocandins are generally considered fungistatic against Aspergillus species. METHODS: Culture of A. fumigatus from conidia to microcolonies on a support of porous aluminium oxide (PAO, combined with fluorescence microscopy and scanning electron microscopy, was used to investigate the effects of anidulafungin and caspofungin. The PAO was an effective matrix for conidial germination and microcolony growth. Additionally, PAO supports could be moved between agar plates containing different concentrations of echinocandins to change dosage and to investigate the recovery of fungal microcolonies from these drugs. Culture on PAO combined with microscopy and image analysis permits quantitative studies on microcolony growth with the flexibility of adding or removing antifungal agents, dyes, fixatives or osmotic stresses during growth with minimal disturbance of fungal microcolonies. SIGNIFICANCE: Anidulafungin and caspofungin reduced but did not halt growth at the microcony level; additionally both drugs killed individual cells, particularly at concentrations around the MIC. Intact but not lysed cells showed rapid recovery when the drugs were removed. The classification of these drugs as either fungistatic or fungicidal is simplistic. Microcolony analysis on PAO appears to be a valuable tool to investigate the action of antifungal agents.

  16. Preliminary evaluation of fungicidal and termiticidal activities of filtrates from biomass slurry fuel production.

    Science.gov (United States)

    Kartal, S N; Imamura, Y; Tsuchiya, F; Ohsato, K

    2004-10-01

    Biomass slurry fuel (BSF) production has recently been developed as a natural energy for the conversion of solid biomass into fuel. In addition to using fuel, filtrates from BSF production may also serve a chemical source with several organic compounds. There is an increasing interest in the research and application of biomass-based filtrates. In this study, fungicidal and termiticidal properties of filtrates from BSF production using sugi (Cryptomeria japonica) and acacia (Acacia mangium) wood were evaluated in laboratory decay and termite resistance tests. Wood blocks treated with the filtrates showed increased resistance against brown-rot fungus, Fomitopsis palustris. However the filtrates from sugi wood processed at 270 degrees C which contained less phenolic compounds than the other filtrates were effective against white-rot fungus, Trametes versicolor. Phenolic compounds of filtrates seemed to play a role in the decay resistance tests however the filtrates did not increase the durability of the wood blocks against subterranean termites Coptotermes formosanus. Despite high acetic and lactic acid content of the filtrates, vanillin content of the filtrates may have served as an additional food source and promoted termite attack. It can be concluded that filtrates with phenolic compounds from lignin degradation during BSF production can be considered for targeted inhibition of brown-rot.

  17. Assessment of azole fungicides as a tool to control growth of Aspergillus flavus and aflatoxin B1and B2production in maize.

    Science.gov (United States)

    Mateo, Eva M; Gómez, José Vicente; Gimeno-Adelantado, José Vicente; Romera, David; Mateo-Castro, Rufino; Jiménez, Misericordia

    2017-06-01

    Aspergillus flavus is a highly aflatoxin (AF)-producing species infecting maize and other crops. It is dominant in tropical regions, but it is also considered an emerging problem associated with climate change in Europe. The aim of this study was to assess the efficacy of azole fungicides (prochloraz, tebuconazole and a 2:1 (w/w) mixture of prochloraz plus tebuconazole) to control the growth of A. flavus and AF production in yeast-extract-sucrose (YES) agar and in maize kernels under different water activities (a w ) and temperatures. Aflatoxins B 1 and B 2 were determined by LC with fluorescence detection and post-column derivatisation of AFB 1 . In YES medium and maize grains inoculated with conidia of A. flavus, the growth rate (GR) of the fungus and AFB 1 and AFB 2 production were significantly influenced by temperature and treatment. In YES medium and maize kernels, optimal temperatures for GR and AF production were 37 and 25°C, respectively. In maize kernels, spore germination was not detected at the combination 37ºC/0.95 a w ; however, under these conditions germination was found in YES medium. All fungicides were more effective at 0.99 than 0.95 a w , and at 37 than 25ºC. Fungicides effectiveness was prochloraz > prochloraz plus tebuconazole (2:1) > tebuconazole. AFs were not detected in cultures containing the highest fungicide doses, and only very low AF levels were found in cultures containing 0.1 mg l - 1 prochloraz or 5.0 mg l - 1 tebuconazole. Azoles proved to be highly efficient in reducing A. flavus growth and AF production, although stimulation of AF production was found under particular conditions and low-dosage treatments. Maize kernels were a more favourable substrate for AF biosynthesis than YES medium. This paper is the first comparative study on the effects of different azole formulations against A. flavus and AF production in a semi-synthetic medium and in maize grain under different environmental conditions.

  18. The rising threat of fungicide resistance in plant pathogenic fungi: Botrytis as a case study.

    Science.gov (United States)

    Hahn, Matthias

    2014-10-01

    The introduction of site-specific fungicides almost 50 years ago has revolutionized chemical plant protection, providing highly efficient, low toxicity compounds for control of fungal diseases. However, it was soon discovered that plant pathogenic fungi can adapt to fungicide treatments by mutations leading to resistance and loss of fungicide efficacy. The grey mould fungus Botrytis cinerea, a major cause of pre- and post-harvest losses in fruit and vegetable production, is notorious as a 'high risk' organism for rapid resistance development. In this review, the mechanisms and the history of fungicide resistance in Botrytis are outlined. The introduction of new fungicide classes for grey mould control was always followed by the appearance of resistance in field populations. In addition to target site resistance, B. cinerea has also developed a resistance mechanism based on drug efflux transport. Excessive spraying programmes have resulted in the selection of multiresistant strains in several countries, in particular in strawberry fields. The rapid erosion of fungicide activity against these strains represents a major challenge for the future of fungicides against Botrytis. To maintain adequate protection of intensive cultures against grey mould, strict implementation of resistance management measures are required as well as alternative strategies with non-chemical products.

  19. Effects of Fungicides, Time of Application, and Application Method on Control of Sclerotinia Blight in Peanut

    Directory of Open Access Journals (Sweden)

    Jason E. Woodward

    2015-01-01

    Full Text Available Field studies were conducted from 2007 to 2010 to evaluate the response of peanut cultivars to different fungicides, application timings, and methods. Overall, fungicides reduced Sclerotinia blight incidence and increased pod yields when applied to susceptible and partially resistant cultivars. Disease suppression was greater when full fungicide rates were applied preventatively; however, yields between fungicide treated plots were similar. Lower levels of disease and higher yields were achieved with the partially resistant cultivar Tamrun OL07 compared to the susceptible cultivars Flavor Runner 458 and Tamrun OL 02. Despite possessing improved resistance Tamrun OL07 responded to all fungicide applications. While similar levels of disease control were achieved with broadcast or banded applications made during the day or at night, the yield response for the different application methods was inconsistent among years. A negative relationship (slope = −73.8; R2=0.73; P<0.01 was observed between final disease incidence ratings and yield data from studies where a fungicide response was observed. These studies suggest that both boscalid and fluazinam are effective at controlling Sclerotinia blight in peanuts. Alternative management strategies such as nighttime and banded applications could allow for lower fungicide rates to be used; however, additional studies are warranted.

  20. Spread of Botrytis cinerea Strains with Multiple Fungicide Resistance in German Horticulture

    Science.gov (United States)

    Rupp, Sabrina; Weber, Roland W. S.; Rieger, Daniel; Detzel, Peter; Hahn, Matthias

    2017-01-01

    Botrytis cinerea is a major plant pathogen, causing gray mold rot in a variety of cultures. Repeated fungicide applications are common but have resulted in the development of fungal populations with resistance to one or more fungicides. In this study, we have monitored fungicide resistance frequencies and the occurrence of multiple resistance in Botrytis isolates from raspberries, strawberries, grapes, stone fruits and ornamental flowers in Germany in 2010 to 2015. High frequencies of resistance to all classes of botryticides was common in all cultures, and isolates with multiple fungicide resistance represented a major part of the populations. A monitoring in a raspberry field over six seasons revealed a continuous increase in resistance frequencies and the emergence of multiresistant Botrytis strains. In a cherry orchard and a vineyard, evidence of the immigration of multiresistant strains from the outside was obtained. Inoculation experiments with fungicide-treated leaves in the laboratory and with strawberry plants cultivated in the greenhouse or outdoors revealed a nearly complete loss of fungicide efficacy against multiresistant strains. B. cinerea field strains carrying multiple resistance mutations against all classes of site-specific fungicides were found to show similar fitness as sensitive field strains under laboratory conditions, based on their vegetative growth, reproduction, stress resistance, virulence and competitiveness in mixed infection experiments. Our data indicate an alarming increase in the occurrence of multiresistance in B. cinerea populations from different cultures, which presents a major threat to the chemical control of gray mold. PMID:28096799

  1. Spread of Botrytis cinerea Strains with Multiple Fungicide Resistance in German Horticulture.

    Science.gov (United States)

    Rupp, Sabrina; Weber, Roland W S; Rieger, Daniel; Detzel, Peter; Hahn, Matthias

    2016-01-01

    Botrytis cinerea is a major plant pathogen, causing gray mold rot in a variety of cultures. Repeated fungicide applications are common but have resulted in the development of fungal populations with resistance to one or more fungicides. In this study, we have monitored fungicide resistance frequencies and the occurrence of multiple resistance in Botrytis isolates from raspberries, strawberries, grapes, stone fruits and ornamental flowers in Germany in 2010 to 2015. High frequencies of resistance to all classes of botryticides was common in all cultures, and isolates with multiple fungicide resistance represented a major part of the populations. A monitoring in a raspberry field over six seasons revealed a continuous increase in resistance frequencies and the emergence of multiresistant Botrytis strains. In a cherry orchard and a vineyard, evidence of the immigration of multiresistant strains from the outside was obtained. Inoculation experiments with fungicide-treated leaves in the laboratory and with strawberry plants cultivated in the greenhouse or outdoors revealed a nearly complete loss of fungicide efficacy against multiresistant strains. B. cinerea field strains carrying multiple resistance mutations against all classes of site-specific fungicides were found to show similar fitness as sensitive field strains under laboratory conditions, based on their vegetative growth, reproduction, stress resistance, virulence and competitiveness in mixed infection experiments. Our data indicate an alarming increase in the occurrence of multiresistance in B. cinerea populations from different cultures, which presents a major threat to the chemical control of gray mold.

  2. Consequences of co-applying insecticides and fungicides for managing Thrips tabaci (Thysanoptera: Thripidae) on onion.

    Science.gov (United States)

    Nault, Brian A; Hsu, Cynthia L; Hoepting, Christine A

    2013-07-01

    Insecticides and fungicides are commonly co-applied in a tank mix to protect onions from onion thrips, Thrips tabaci Lindeman, and foliar pathogens. Co-applications reduce production costs, but past research shows that an insecticide's performance can be reduced when co-applied with a fungicide. An evaluation was made of the effects of co-applying spinetoram, abamectin and spirotetramat with commonly used fungicides, with and without the addition of a penetrating surfactant, on onion thrips control in onion fields. Co-applications of insecticides with chlorothalonil fungicides reduced thrips control by 25-48% compared with control levels provided by the insecticides alone in three of five trials. Inclusion of a penetrating surfactant at recommended rates with the insecticide and chlorothalonil fungicide did not consistently overcome this problem. Co-applications of insecticides with other fungicides did not interfere with thrips control. Co-applications of pesticides targeting multiple organisms should be examined closely to ensure that control of each organism is not compromised. To manage onion thrips in onion most effectively, insecticides should be applied with a penetrating surfactant, and should be applied separately from chlorothalonil fungicides. © 2012 Society of Chemical Industry.

  3. Fungicidal property of Curcuma longa L. rhizome-derived curcumin against phytopathogenic fungi in a greenhouse.

    Science.gov (United States)

    Kim, Moo-Key; Choi, Gyung-Ja; Lee, Hoi-Seon

    2003-03-12

    Fungicidal activity of Curcuma longa rhizome-derived materials against Botrytis cineria, Erysiphe graminis, Phytophthora infestans, Puccinia recondita, Pyricularia oryzae, and Rhizoctonia solani was tested using a whole plant method in vivo. It was compared with synthetic fungicides and four commercially available compounds derived from C. longa. The response varied with the tested plant pathogen. At 1000 mg/L, the hexane extract of C. longa showed fungicidal activities against E.graminis, P. infestans, and R. solani, and the ethyl acetate extract of C. longa showed fungicidal activities against B. cineria, P. infestans, Pu. recondita, and R. solani. Curcumin was isolated from the ethyl acetate fraction using chromatographic techniques and showed fungicidal activities against P. infestans, Pu. recondita, and R. solani with 100, 100, and 63% control values at 500 mg/L and 85, 76, and 45% control values at 250 mg/L, respectively. In the test with components derived from C. longa, turmerone exhibited weak activity against E. graminis, but no activity was observed from treatments with borneol, 1,8-cineole, sabinene, and turmerone. In comparison, potent fungicidal activity with chlorothalonil against P. infestans at 50 mg/L and dichlofluanid against B. cinerea at 50 mg/L was exhibited. These results may be an indication of at least one of the fungicidal actions of curcumin derived from C. longa.

  4. (-)-Menthol biosynthesis and molecular genetics

    Science.gov (United States)

    Croteau, Rodney B.; Davis, Edward M.; Ringer, Kerry L.; Wildung, Mark R.

    2005-12-01

    (-)-Menthol is the most familiar of the monoterpenes as both a pure natural product and as the principal and characteristic constituent of the essential oil of peppermint ( Mentha x piperita). In this paper, we review the biosynthesis and molecular genetics of (-)-menthol production in peppermint. In Mentha species, essential oil biosynthesis and storage is restricted to the peltate glandular trichomes (oil glands) on the aerial surfaces of the plant. A mechanical method for the isolation of metabolically functional oil glands, has provided a system for precursor feeding studies to elucidate pathway steps, as well as a highly enriched source of the relevant biosynthetic enzymes and of their corresponding transcripts with which cDNA libraries have been constructed to permit cloning and characterization of key structural genes. The biosynthesis of (-)-menthol from primary metabolism requires eight enzymatic steps, and involves the formation and subsequent cyclization of the universal monoterpene precursor geranyl diphosphate to the parent olefin (-)-(4 S)-limonene as the first committed reaction of the sequence. Following hydroxylation at C3, a series of four redox transformations and an isomerization occur in a general “allylic oxidation-conjugate reduction” scheme that installs three chiral centers on the substituted cyclohexanoid ring to yield (-)-(1 R, 3 R, 4 S)-menthol. The properties of each enzyme and gene of menthol biosynthesis are described, as are their probable evolutionary origins in primary metabolism. The organization of menthol biosynthesis is complex in involving four subcellular compartments, and regulation of the pathway appears to reside largely at the level of gene expression. Genetic engineering to up-regulate a flux-limiting step and down-regulate a side route reaction has led to improvement in the composition and yield of peppermint oil.

  5. Fungicide application method’ and the interpretation of mycorrhizal fungus insect indirect effects

    Science.gov (United States)

    Laird, Robert A.; Addicott, John F.

    2008-09-01

    Mycorrhizal fungi, by altering their host plant's physiology, can have indirect effects on insect herbivores. The 'fungicide application method' is a common approach used to investigate the indirect effects of mycorrhizal fungi on insects. This approach works by using initially mycorrhizal plants, and then generating a subset of these plants that are free of mycorrhizal fungi by applying fungicide to their roots. When insect feeding-bioassays are conducted using the resulting mycorrhizal and non-mycorrhizal plants, differences in insect performance are typically attributed to differences in mycorrhizal colonization per se, rather than the application of the fungicide. Thus, the fungicide application method relies on the assumption that there is no direct toxicity of the fungicide on the focal insect species, and no indirect effects on the focal insect resulting from effects of the fungicide on the host plant or on non-target soil micro-organisms. We tested this critical assumption by feeding Zygogramma exclamationis (Chrysomelidae) larvae on non-mycorrhizal Helianthus annuus (Asteraceae) plants whose roots were treated with a solution of the fungicide benomyl or with a distilled water control. Larvae fed on benomyl-treated plants had reduced survival, lower relative growth rate, and lower food conversion efficiency, compared to larvae fed on control plants. Hence, fungicides applied to roots can affect herbivorous insect performance even in the absence of the possibility of mycorrhizal fungi-mediated effects. We recommend caution when using fungicide application and suggest that selective inoculation is a preferable method of generating mycorrhizal and non-mycorrhizal plants when studying mycorrhizal fungi-insect indirect effects.

  6. Additive and synergistic antiandrogenic activities of mixtures of azol fungicides and vinclozolin

    Energy Technology Data Exchange (ETDEWEB)

    Christen, Verena [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Crettaz, Pierre [Federal Office of Public Health, Division Chemical Products, 3003 Bern (Switzerland); Fent, Karl, E-mail: karl.fent@fhnw.ch [University of Applied Sciences and Arts Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); ETH Zürich, Department of Environmental System Sciences, Institute of Biogeochemistry and Pollution Dynamics, Universitätsstrasse 16, CH-8092 Zürich (Switzerland)

    2014-09-15

    Objective: Many pesticides including pyrethroids and azole fungicides are suspected to have an endocrine disrupting property. At present, the joint activity of compound mixtures is only marginally known. Here we tested the hypothesis that the antiandrogenic activity of mixtures of azole fungicides can be predicted by the concentration addition (CA) model. Methods: The antiandrogenic activity was assessed in MDA-kb2 cells. Following assessing single compounds activities mixtures of azole fungicides and vinclozolin were investigated. Interactions were analyzed by direct comparison between experimental and estimated dose–response curves assuming CA, followed by an analysis by the isobole method and the toxic unit approach. Results: The antiandrogenic activity of pyrethroids deltamethrin, cypermethrin, fenvalerate and permethrin was weak, while the azole fungicides tebuconazole, propiconazole, epoxiconazole, econazole and vinclozolin exhibited strong antiandrogenic activity. Ten binary and one ternary mixture combinations of five antiandrogenic fungicides were assessed at equi-effective concentrations of EC{sub 25} and EC{sub 50}. Isoboles indicated that about 50% of the binary mixtures were additive and 50% synergistic. Synergism was even more frequently indicated by the toxic unit approach. Conclusion: Our data lead to the conclusion that interactions in mixtures follow the CA model. However, a surprisingly high percentage of synergistic interactions occurred. Therefore, the mixture activity of antiandrogenic azole fungicides is at least additive. Practice: Mixtures should also be considered for additive antiandrogenic activity in hazard and risk assessment. Implications: Our evaluation provides an appropriate “proof of concept”, but whether it equally translates to in vivo effects should further be investigated. - Highlights: • Humans are exposed to pesticide mixtures such as pyrethroids and azole fungicides. • We assessed the antiandrogenicity of

  7. Strong lethality and teratogenicity of strobilurins on Xenopus tropicalis embryos: Basing on ten agricultural fungicides

    International Nuclear Information System (INIS)

    Li, Dan; Liu, Mengyun; Yang, Yongsheng; Shi, Huahong; Zhou, Junliang; He, Defu

    2016-01-01

    Agricultural chemical inputs have been considered as a risk factor for the global declines in amphibian populations, yet the application of agricultural fungicides has increased dramatically in recent years. Currently little is known about the potential toxicity of fungicides on the embryos of amphibians. We studied the effects of ten commonly used fungicides (four strobilurins, two SDHIs, two triazoles, fludioxonil and folpet) on Xenopus tropicalis embryos. Lethal and teratogenic effects were respectively examined after 48 h exposure. The median lethal concentrations (LC50s) and the median teratogenic concentrations (TC50s) were determined in line with actual exposure concentrations. These fungicides except two triazoles showed obvious lethal effects on embryos; however LC50s of four strobilurins were the lowest and in the range of 6.81–196.59 μg/L. Strobilurins, SDHIs and fludioxonil induced severe malformations in embryos. Among the ten fungicides, the lowest TC50s were observed for four strobilurins in the range of 0.61–84.13 μg/L. The teratogenicity shared similar dose–effect relationship and consistent phenotypes mainly including microcephaly, hypopigmentation, somite segmentation and narrow fins. The findings indicate that the developmental toxicity of currently-used fungicides involved with ecologic risks on amphibians. Especially strobilurins are highly toxic to amphibian embryos at μg/L level, which is close to environmentally relevant concentrations. - Highlights: • Effects of ten agricultural fungicides were tested on Xenopus tropicalis embryos. • Strobilurin fungicides showed strong lethal and teratogenic effects on embryos. • Lowest LC50 and TC50 were observed for strobilurins in ten fungicides. • μg/L level of toxic concentrations for strobilurins was environmentally relevant. • Teratogenicity shared similar dose–effect relationship and main phenotypes. - Strobilurins induced strong lethality and teratogenicity on Xenopus

  8. Chemical management in fungicide sensitivity of Mycosphaerella fijiensis collected from banana fields in México.

    Science.gov (United States)

    Aguilar-Barragan, Alejandra; García-Torres, Ana Elisa; Odriozola-Casas, Olga; Macedo-Raygoza, Gloria; Ogura, Tetsuya; Manzo-Sánchez, Gilberto; James, Andrew C; Islas-Flores, Ignacio; Beltrán-García, Miguel J

    2014-01-01

    The chemical management of the black leaf streak disease in banana caused by Mycosphaerella fijiensis (Morelet) requires numerous applications of fungicides per year. However this has led to fungicide resistance in the field. The present study evaluated the activities of six fungicides against the mycelial growth by determination of EC50 values of strains collected from fields with different fungicide management programs: Rustic management (RM) without applications and Intensive management (IM) more than 25 fungicide application/year. Results showed a decreased sensitivity to all fungicides in isolates collected from IM. Means of EC50 values in mg L(-1) for RM and IM were: 13.25 ± 18.24 and 51.58 ± 46.14 for azoxystrobin, 81.40 ± 56.50 and 1.8575 ± 2.11 for carbendazim, 1.225 ± 0.945 and 10.01 ± 8.55 for propiconazole, 220 ± 67.66 vs. 368 ± 62.76 for vinclozolin, 9.862 ± 3.24 and 54.5 ± 21.08 for fludioxonil, 49.2125 ± 34.11 and 112.25 ± 51.20 for mancozeb. A molecular analysis for β-tubulin revealed a mutation at codon 198 in these strains having an EC50 greater than 10 mg L(-1) for carbendazim. Our data indicate a consistency between fungicide resistance and intensive chemical management in banana fields, however indicative values for resistance were also found in strains collected from rustic fields, suggesting that proximity among fields may be causing a fungus interchange, where rustic fields are breeding grounds for development of resistant strains. Urgent actions are required in order to avoid fungicide resistance in Mexican populations of M. fijiensis due to fungicide management practices.

  9. Chemical management in fungicide sensivity of Mycosphaerella fijiensis collected from banana fields in México

    Science.gov (United States)

    Aguilar-Barragan, Alejandra; García-Torres, Ana Elisa; Odriozola-Casas, Olga; Macedo-Raygoza, Gloria; Ogura, Tetsuya; Manzo-Sánchez, Gilberto; James, Andrew C.; Islas-Flores, Ignacio; Beltrán-García, Miguel J.

    2014-01-01

    The chemical management of the black leaf streak disease in banana caused by Mycosphaerella fijiensis (Morelet) requires numerous applications of fungicides per year. However this has led to fungicide resistance in the field. The present study evaluated the activities of six fungicides against the mycelial growth by determination of EC50 values of strains collected from fields with different fungicide management programs: Rustic management (RM) without applications and Intensive management (IM) more than 25 fungicide application/year. Results showed a decreased sensitivity to all fungicides in isolates collected from IM. Means of EC50 values in mg L−1 for RM and IM were: 13.25 ± 18.24 and 51.58 ± 46.14 for azoxystrobin, 81.40 ± 56.50 and 1.8575 ± 2.11 for carbendazim, 1.225 ± 0.945 and 10.01 ± 8.55 for propiconazole, 220 ± 67.66 vs. 368 ± 62.76 for vinclozolin, 9.862 ± 3.24 and 54.5 ± 21.08 for fludioxonil, 49.2125 ± 34.11 and 112.25 ± 51.20 for mancozeb. A molecular analysis for β-tubulin revealed a mutation at codon 198 in these strains having an EC50 greater than 10 mg L−1 for carbendazim. Our data indicate a consistency between fungicide resistance and intensive chemical management in banana fields, however indicative values for resistance were also found in strains collected from rustic fields, suggesting that proximity among fields may be causing a fungus interchange, where rustic fields are breeding grounds for development of resistant strains. Urgent actions are required in order to avoid fungicide resistance in Mexican populations of M. fijiensis due to fungicide management practices. PMID:24948956

  10. Chemical management in fungicide sensivity of Mycosphaerella fijiensis collected from banana fields in México

    Directory of Open Access Journals (Sweden)

    Alejandra Aguilar-Barragan

    2014-01-01

    Full Text Available The chemical management of the black leaf streak disease in banana caused by Mycosphaerella fijiensis (Morelet requires numerous applications of fungicides per year. However this has led to fungicide resistance in the field. The present study evaluated the activities of six fungicides against the mycelial growth by determination of EC50 values of strains collected from fields with different fungicide management programs: Rustic management (RM without applications and Intensive management (IM more than 25 fungicide application/year. Results showed a decreased sensitivity to all fungicides in isolates collected from IM. Means of EC50 values in mg L-1 for RM and IM were: 13.25 ± 18.24 and 51.58 ± 46.14 for azoxystrobin, 81.40 ± 56.50 and 1.8575 ± 2.11 for carbendazim, 1.225 ± 0.945 and 10.01 ± 8.55 for propiconazole, 220 ± 67.66 vs. 368 ± 62.76 for vinclozolin, 9.862 ± 3.24 and 54.5 ± 21.08 for fludioxonil, 49.2125 ± 34.11 and 112.25 ± 51.20 for mancozeb. A molecular analysis for β-tubulin revealed a mutation at codon 198 in these strains having an EC50 greater than 10 mg L-1 for carbendazim. Our data indicate a consistency between fungicide resistance and intensive chemical management in banana fields, however indicative values for resistance were also found in strains collected from rustic fields, suggesting that proximity among fields may be causing a fungus interchange, where rustic fields are breeding grounds for development of resistant strains. Urgent actions are required in order to avoid fungicide resistance in Mexican populations of M. fijiensis due to fungicide management practices.

  11. Sertraline demonstrates fungicidal activity in vitro for Coccidioides immitis

    Directory of Open Access Journals (Sweden)

    Simon Paul

    2016-07-01

    Full Text Available Coccidioidomycosis causes substantial morbidity in endemic areas. Disseminated coccidioidomycosis is an AIDS defining condition and treatment often requires lifelong antifungal therapy. Sertraline, a widely used serotonin-reuptake inhibitor anti-depressant, has demonstrated activity against Candida and Cryptococcus sp. both in vitro and in vivo. To evaluate if sertraline has activity against Coccidioides, the minimal inhibitory concentration (MIC and minimal fungicidal concentration (MFC of sertraline for four clinical isolates of C. immitis were determined. Sertraline was observed to have an MIC range of 4–8 µg/ml and MFC also of 4–8 µg/ml for Coccidioides. These MIC and MFC results for C. immitis are similar to those reported for Cryptococcus sp. suggesting sertraline may potentially have utility for the treatment of coccidioidomycosis.

  12. Azole Fungicides as Synergists in the Aquatic Environment

    DEFF Research Database (Denmark)

    Bjergager, Maj-Britt Andersen

    hazard.This PhD thesis evaluates the role of the so called azole fungicides as synergists in the aquaticenvironment through an assessment of the effect of sorption, time and azole concentration on theoccurrence and magnitude of synergistic interactions with pyrethroid insecticides towards...... the aquaticcrustacean Daphnia magna in both laboratory experiments and natural-like environments. In the PhDthesis, synergy is defined as happening in mixtures where either EC50 values decrease more than two-foldbelow the prediction by the model of Concentration Addition (horizontal assessment of synergy) or wherethe...... in stormwater runoff ordrain water and in the aquatic environment, the pesticides mainly occur in sorbed form. Sorption istraditionally considered to limit bioaccessibility and toxicity of hydrophobic compounds, hence,synergistic interactions may be limited in natural environments compared to laboratory studies...

  13. Endocrine disrupting properties in vivo of widely used azole fungicides

    DEFF Research Database (Denmark)

    Taxvig, Camilla; Vinggaard, Anne; Hass, Ulla

    2008-01-01

    The endocrine-disrupting potential of four commonly used azole fungicides, propiconazole, tebuconazole, epoxiconazole and ketoconazole, were tested in two short-term in vivo studies. Initially, the antiandrogenic effects of propiconazole and tebuconazole (50, 100 and 150 mg/kg body weight/day each......) were examined in the Hershberger assay. In the second study, pregnant Wistar rats were dosed with propiconazole, tebuconazole, epoxiconazole or ketoconazole (50 mg/kg/day each) from gestational day (GD) 7 to GD 21. Caesarian sections were performed on dams at GD 21. Tebuconazole and propiconazole...... demonstrated no antiandrogenic effects at doses between 50 and 150 mg/kg body weight/day in the Hershberger assay. In the in utero exposure toxicity study, ketoconazole, a pharmaceutical to treat human fungal infections, decreased anogenital distance and reduced testicular testosterone levels, demonstrating...

  14. Persistence behaviour of fungicide tebuconazole in a viticulture application.

    Science.gov (United States)

    Kundu, Chiranjit; Goon, Arnab; Bhattacharyya, Anjan

    2014-04-01

    Dissipation pattern and risk assessment of tebuconazole in grapes was studied following two application rates (250 and 500 mL ha(-1)) under tropical humid climatic condition of West Bengal during 2009-2010. Residues of tebuconazole were confirmed by liquid chromatography-mass spectrometry. The average recoveries were found 87.53 % and 89.67 % for grapes and cropped soil respectively. Following the first order kinetics the fungicide dissipates in grapes with a half-life (T1/2) value ranges between 2.62 and 2.86 days irrespective of seasons and doses. No residues of tebuconazole were detected in harvest grapes and soil samples which refers that, tebuconazole does not possess any background contamination property in grapes. So it may be concluded from the study that tebuconazole does not possess any toxicological property when applied at the recommended dose.

  15. Fatty Acid Biosynthesis IX

    DEFF Research Database (Denmark)

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...... synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids....... Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles...

  16. Aggregative stability of fungicidal nanomodifier based on zinc hydrosilicates

    Science.gov (United States)

    Grishina, Anna; Korolev, Evgeniy

    2018-03-01

    Currently, there is a strong need of high performance multi functional materials in high-rise construction. Obviously, such materials should be characterized by high strength; but for interior rooms biosafety is important as well. The promising direction to obtain both high strength and maintain biosafety in buildings and structures is to manage the structure of mineral binders by means of fungicidal nanomodifier based on zinc hydrosilicates. In the present work the aggregative stability of colloidal solutions of zinc hydrosilicates after one year of storage was studied. It has been established that the concentration of iron (III) hydroxide used to prepare the precursor of zinc hydrosilicates has a significant effect on the long-term aggregative stability: as the concentration of iron (III) hydroxide increases, the resistance of the fungicidal nanomodifier increases. It was found that, despite the minimal concentration of nano-sized zinc hydrosilicates (0.028%), the colloidal solution possesses a low long-term aggregative stability; while in the initial period (not less than 14 days) the colloidal solution of the nanomodifier is aggregatively stable. It is shown that when the ratio in the colloidal solution of the amount of the substance CH3COOH / SiO2 = 0.43 is reached, an increase in the polymerization rate is observed, which is the main cause of low aggregative stability. Colloidal solutions containing zinc hydrosilicates synthesized at a concentration of iron (III) hydroxide used to produce a precursor equal to 0.7% have a long-term aggregative stability and do not significantly change the reduced particle. Such compositions are to be expediently used for the nanomodifying of building composites in order to control their structure formation and to create conditions that impede the development of various mycelial fungi.

  17. Enzymatic basis for fungicide removal by Elodea canadensis.

    Science.gov (United States)

    Dosnon-Olette, Rachel; Schröder, Peter; Bartha, Bernadett; Aziz, Aziz; Couderchet, Michel; Eullaffroy, Philippe

    2011-07-01

    Plants can absorb a diversity of natural and man-made toxic compounds for which they have developed diverse detoxification mechanisms. Plants are able to metabolize and detoxify a wide array of xenobiotics by oxidation, sugar conjugation, glutathione conjugation, and more complex reactions. In this study, detoxification mechanisms of dimethomorph, a fungicide currently found in aquatic media were investigated in Elodea canadensis. Cytochrome P450 (P450) activity was measured by an oxygen biosensor system, glucosyltransferases (GTs) by HPLC, glutathione S-transferases (GSTs), and ascorbate peroxidase (APOX) were assayed spectrophotometrically. Incubation of Elodea with dimethomorph induced an increase of the P450 activity. GST activity was not stimulated by dimethomorph suggesting that GST does not participate in dimethomorph detoxification. In plants exposed to dimethomorph, comparable responses were observed for GST and APOX activities showing that the GST was more likely to play a role in response to oxidative stress. Preincubation with dimethomorph induced a high activity of O- and N-GT, it is therefore likely that both enzymes participate in the phase II (conjugation) of dimethomorph detoxification process. For the first time in aquatic plants, P450 activity was shown to be induced by a fungicide suggesting a role in the metabolization of dimethomorph. Moreover, our finding is the first evidence of dimethomorph and isoproturon activation of cytochrome P450 multienzyme family in an aquatic plant, i.e., Elodea (isoproturon was taken here as a reference molecule). The detoxification of dimetomorph seems to proceed via hydroxylation, and subsequent glucosylation, and might yield soluble as well as cell wall bound residues.

  18. The fungicide mancozeb induces toxic effects on mammalian granulosa cells

    Energy Technology Data Exchange (ETDEWEB)

    Paro, Rita [Department of Health Sciences, University of L' Aquila, Via Vetoio, L' Aquila (Italy); Tiboni, Gian Mario [Department of Medicine and Aging, Section of Reproductive Sciences, University “G. D' Annunzio”, Chieti-Pescara (Italy); Buccione, Roberto [Tumor Cell Invasion Laboratory, Consorzio Mario Negri Sud, Santa Maria Imbaro, Chieti (Italy); Rossi, Gianna; Cellini, Valerio [Department of Health Sciences, University of L' Aquila, Via Vetoio, L' Aquila (Italy); Canipari, Rita [Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Section of Histology and Embryology, School of Pharmacy and Medicine, “Sapienza” University of Rome, Rome (Italy); Cecconi, Sandra, E-mail: sandra.cecconi@cc.univaq.it [Department of Health Sciences, University of L' Aquila, Via Vetoio, L' Aquila (Italy)

    2012-04-15

    The ethylene-bis-dithiocarbamate mancozeb is a widely used fungicide with low reported toxicity in mammals. In mice, mancozeb induces embryo apoptosis, affects oocyte meiotic spindle morphology and impairs fertilization rate even when used at very low concentrations. We evaluated the toxic effects of mancozeb on the mouse and human ovarian somatic granulosa cells. We examined parameters such as cell morphology, induction of apoptosis, and p53 expression levels. Mouse granulosa cells exposed to mancozeb underwent a time- and dose-dependent modification of their morphology, and acquired the ability to migrate but not to proliferate. The expression level of p53, in terms of mRNA and protein content, decreased significantly in comparison with unexposed cells, but no change in apoptosis was recorded. Toxic effects could be attributed, at least in part, to the presence of ethylenthiourea (ETU), the main mancozeb catabolite, which was found in culture medium. Human granulosa cells also showed dose-dependent morphological changes and reduced p53 expression levels after exposure to mancozeb. Altogether, these results indicate that mancozeb affects the somatic cells of the mammalian ovarian follicles by inducing a premalignant-like status, and that such damage occurs to the same extent in both mouse and human GC. These results further substantiate the concept that mancozeb should be regarded as a reproductive toxicant. Highlights: ► The fungicide mancozeb affects oocyte spindle morphology and fertilization rate. ► We investigated the toxic effects of mancozeb on mouse and human granulosa cells. ► Granulosa cells modify their morphology and expression level of p53. ► Mancozeb induces a premalignant-like status in exposed cells.

  19. Efficiency of Elite Fungicide for Control of Pistachio Gummosis

    Directory of Open Access Journals (Sweden)

    Mohammad Moradi

    2017-05-01

    Full Text Available Several species of Phytophthora cause crown and root rot diseases of herbaceous and woody plants. Crown and root rot of pistachio trees cause significant damages in infected orchards. The effect of foliar application with Elite (fosetyl-Al in 2 and 2.5 g/l was evaluated in greenhouse experiments. The frequency of mortality, fresh and dry weight of roots and shoots, height, intensity of crown root colonization using CAMA-PARP medium was determined. Under greenhouse experiments, foliar application with Elite increased height, fresh and dry weight of shoots and root either in inoculation with and without Phytophthora drechsleri. The effects of Elite were more pronounced in roots, which increased the fresh and dry weight of root 1.3 and 2.5 times compared to those not sprayed with Elite, respectively. On the other hand, the application of Elite before or on the day of inoculation significantly reduced the frequency of mortality, which ranged from 35 to 90% (P ≤ 0.01. Crown and root colonization of pistachio seedling was affected by both the concentration of Elite and reduced the frequency of crown and root colonization of seedling. When fungicide and pathogen were applied at the same time, the frequency of colonization reduced to 18% and 36% for 2 and 2.5 g/l, respectively, and 43% and 60% when seedlings were treated with fungicide before P. drechsleri inoculations. The highest effect was seen in foliar application of Elite seven days before inoculation in 2.5 g/l. Further investigations have been conducted to understand the effect of Elite in infected trees as well as modeling of Elite application via soil drench, foliar application or trunk injection.

  20. Combination Effects of (TriAzole Fungicides on Hormone Production and Xenobiotic Metabolism in a Human Placental Cell Line

    Directory of Open Access Journals (Sweden)

    Svenja Rieke

    2014-09-01

    Full Text Available Consumers are exposed to multiple residues of different pesticides via the diet. Therefore, EU legislation for pesticides requires the evaluation of single active substances as well as the consideration of combination effects. Hence the analysis of combined effects of substances in a broad dose range represents a key challenge to current experimental and regulatory toxicology. Here we report evidence for additive effects for (triazole fungicides, a widely used group of antifungal agents, in the human placental cell line Jeg-3. In addition to the triazoles cyproconazole, epoxiconazole, flusilazole and tebuconazole and the azole fungicide prochloraz also pesticides from other chemical classes assumed to act via different modes of action (i.e., the organophosphate chlorpyrifos and the triazinylsulfonylurea herbicide triflusulfuron-methyl were investigated. Endpoints analysed include synthesis of steroid hormone production (progesterone and estradiol and gene expression of steroidogenic and non-steroidogenic cytochrome-P-450 (CYP enzymes. For the triazoles and prochloraz, a dose dependent inhibition of progesterone production was observed and additive effects could be confirmed for several combinations of these substances in vitro. The non-triazoles chlorpyrifos and triflusulfuron-methyl did not affect this endpoint and, in line with this finding, no additivity was observed when these substances were applied in mixtures with prochloraz. While prochloraz slightly increased aromatase expression and estradiol production and triflusulfuron-methyl decreased estradiol production, none of the other substances had effects on the expression levels of steroidogenic CYP-enzymes in Jeg-3 cells. For some triazoles, prochloraz and chlorpyrifos a significant induction of CYP1A1 mRNA expression and potential combination effects for this endpoint were observed. Inhibition of CYP1A1 mRNA induction by the AhR inhibitor CH223191 indicated AhR receptor dependence this

  1. Combination effects of (tri)azole fungicides on hormone production and xenobiotic metabolism in a human placental cell line.

    Science.gov (United States)

    Rieke, Svenja; Koehn, Sophie; Hirsch-Ernst, Karen; Pfeil, Rudolf; Kneuer, Carsten; Marx-Stoelting, Philip

    2014-09-17

    Consumers are exposed to multiple residues of different pesticides via the diet. Therefore, EU legislation for pesticides requires the evaluation of single active substances as well as the consideration of combination effects. Hence the analysis of combined effects of substances in a broad dose range represents a key challenge to current experimental and regulatory toxicology. Here we report evidence for additive effects for (tri)azole fungicides, a widely used group of antifungal agents, in the human placental cell line Jeg-3. In addition to the triazoles cyproconazole, epoxiconazole, flusilazole and tebuconazole and the azole fungicide prochloraz also pesticides from other chemical classes assumed to act via different modes of action (i.e., the organophosphate chlorpyrifos and the triazinylsulfonylurea herbicide triflusulfuron-methyl) were investigated. Endpoints analysed include synthesis of steroid hormone production (progesterone and estradiol) and gene expression of steroidogenic and non-steroidogenic cytochrome-P-450 (CYP) enzymes. For the triazoles and prochloraz, a dose dependent inhibition of progesterone production was observed and additive effects could be confirmed for several combinations of these substances in vitro. The non-triazoles chlorpyrifos and triflusulfuron-methyl did not affect this endpoint and, in line with this finding, no additivity was observed when these substances were applied in mixtures with prochloraz. While prochloraz slightly increased aromatase expression and estradiol production and triflusulfuron-methyl decreased estradiol production, none of the other substances had effects on the expression levels of steroidogenic CYP-enzymes in Jeg-3 cells. For some triazoles, prochloraz and chlorpyrifos a significant induction of CYP1A1 mRNA expression and potential combination effects for this endpoint were observed. Inhibition of CYP1A1 mRNA induction by the AhR inhibitor CH223191 indicated AhR receptor dependence this effect.

  2. Field efficacy of different fungicide mixtures in control of net blotch on barley

    Directory of Open Access Journals (Sweden)

    Stepanović Miloš

    2016-01-01

    Full Text Available Seven fungicide mixtures (epoxiconazol + metconazole, boscalid + epoxiconazole, pyraclostrobin + epoxiconazole, prothioconazole + tebuconazole, picoxistrobin + cyproconazole, azoxystrobin + cyproconazole and spiroxamine + tebuconazole + triadimenol were evaluated for control of net blotch of barley caused by Drechslera teres, as well as yield losses, over the 2010 and 2011 growing seasons. Two applications of the fungicide combination pyraclostrobin + epoxiconazole at the rate of 1.0 l ha-1 were the most effective treatment in controlling the disease and improving yield in both experimental years. Treatments with the fungicide mixtures epoxiconazol + metconazole and spiroxamine + tebuconazole + triadimenol showed the least effectiveness in disease control, as well as yield increase.

  3. Regulation of neurosteroid biosynthesis by neurotransmitters and neuropeptides

    Directory of Open Access Journals (Sweden)

    Jean-Luc eDo-Rego

    2012-01-01

    Full Text Available The enzymatic pathways leading to the synthesis of bioactive steroids in the brain are now almost completely elucidated in various groups of vertebrates and, during the last decade, the neuronal mechanisms involved in the regulation of neurosteroid production have received increasing attention. This report reviews the current knowledge concerning the effects of neurotransmitters, peptide hormones and neuropeptides on the biosynthesis of neurosteroids. Anatomical studies have been carried out to visualize the neurotransmitter- or neuropeptide-containing fibers contacting steroid-synthesizing neurons as well as the neurotransmitter, peptide hormones or neuropeptide receptors expressed in these neurons. Biochemical experiments have been conducted to investigate the effects of neurotransmitters, peptide hormones or neuropeptides on neurosteroid biosynthesis, and to characterize the type of receptors involved. Thus, it has been found that glutamate, acting through kainate and/or AMPA receptors, rapidly inactivates P450arom, and that melatonin produced by the pineal gland and eye inhibits the biosynthesis of 7-hydroxypregnenolone (7-OH-5P, while prolactin produced by the adenohypophysis enhances the formation of 7-OH-5P. It has also been demonstrated that the biosynthesis of neurosteroids is inhibited by GABA, acting through GABAA receptors, and neuropeptide Y, acting through Y1 receptors. In contrast, it has been shown that the octadecaneuropetide ODN, acting through central-type benzodiazepine receptors, the triakontatetraneuropeptide TTN, acting though peripheral-type benzodiazepine receptors, and vasotocine, acting through V1a-like receptors, stimulate the production of neurosteroids. Since neurosteroids are implicated in the control of various neurophysiological and behavioral processes, these data suggest that some of the neurophysiological effects exerted by neurotransmitters and neuropeptides may be mediated via the regulation

  4. Synthesis and Fungicidal activity of some sulphide derivatives of O-Ethyl-N-substituted phenylcarbamates

    International Nuclear Information System (INIS)

    Imeokparia, F.A.

    2006-01-01

    Monosulphides of O-ethyl-N-substituted phenylcarbamates were prepared by the reaction between O-ethyl-N-substituted phenylcarbamates and sulphur dichloride, while the corresponding disulphides were prepared by the reaction between O-ethyl-N-substituted phenylcarbamates and sulphur monochloride. The synthesized compounds were characterized by elemental analysis, thin layer chromatography (TLC), Fourier-transform infrared, and /sup 1/H and /sup 13/C nuclear magnetic resonance spectroscopic techniques. In vitro fungicidal assay of these sulphides against Fusarium oxysporum, Aspergillus niger, Aspergillus flavus and Rhizopus stolonifer showed that they had Greater fungicidal activity than their parent carbamates. The synthesized sulphides were more active towards A. Niger and A. flavus. Unlike the parent carbamates, the type of substituents attached to the aromatic nucleus of these sulphides had little or no effect on their fungicidal activity as there was insignificant variation in the fungicidal activity of the monosulphide and the disulphide derivatives of O-ethyl-N-substituted phenylcarbamates. (author)

  5. The effect of selected fungicides on survival of Agrobacterium tumefaciens in various kinds of soils

    Directory of Open Access Journals (Sweden)

    Stanisław Barczyński

    2013-12-01

    Full Text Available The effect of 10 fungicides on survival of A. tumefaciens in various types of soils was studied. In fertile, nonsterile soil Dithane M-45 (mancozeb, Euparen 50 WP (tolyfluanid, Kaptan 50 WP (captan and Ridomil Gold 80 WP (metalaxyl at concentration of 1000 ppm showed the highest antibacterial activity. Similar trends in activity of these fungicides occurred in fertile, sterile soil, however a little lower in case of Kaptan and Euparen. In most of investigated soils Befran 25 SL (imimnoctadyne, Syllit 65 WP (dodine and Thiram Granulfo 80 WG (thiram increased bacteria number. In sandy acidic soil (pH 3,5 all tested fungicides totally eliminated bacteria. On the other hand in sandy neutral soil only Dithane, Euparen, Kaptan and Ridomil showed such activity. Ten fold decrease of fungicides concentration generally did not influence Kaptan and Ridomil effectiveness but it decreased the activity of Dithane and Euparen.

  6. Yield of Potato as Influenced by Crop Sanitation and Reduced Fungicidal Treatments

    Directory of Open Access Journals (Sweden)

    Fontem, DA.

    1995-01-01

    Full Text Available The effects of crop sanitation and reduced sprays of "Ridomil plus®" (12 % metalaxyl + 60 % cuprous oxide on the control of potato (Solanum tuberosum late blight caused by Phytophthora infestans were evaluated in two field experiments in 1993 in Dschang, Cameroon. In the first experiment, sanitation (five weekly removals of blighted leaves and two fungicidal treatments were initiated from first symptoms. In the second experiment, both fungicidal sprays were made at varying rates. Marketable yields increased by 50 % in sanitation-treated plots, by 94 % in plots sprayed with Ridomil plus (2.24 kg a. i./ha, or by 55 % in those exposed to both control methods. The fungicide equivalence of the sanitation treatment was two sprays of Ridomil plus at 0.76 kg a. i./ha. These results suggest that proper removal of diseased leaves or reduced fungicidal protection may be an effective late blight control method in potato farming.

  7. Efficacy of Strobilurin-related and Multi-site Fungicide Mixtures Against Apple Scab

    Directory of Open Access Journals (Sweden)

    Emil Rekanović

    2007-01-01

    Full Text Available The efficacy of several fungicide mixtures in controlling Venturia inaequalis in apple was evaluated in field trials. The efficacies of Flint Plus (trifloxystrobin + captan and Tercel (pyraclostrobin+ dithianon in comparison with standard fungicides Zato 50-WG (trifloxystrobin and Stroby + Delan (kresoxim-methyl + dithianon were tested in the localities Mihajlovac, Radmilovac and Landol in 2004 and 2005. Both tested fungicides exhibited high efficacy in controlling apple scab. There were significant differencies in the efficacies of Flint Plus (91.3-98.5% and Zato 50-WG (68.2% and 78.4%; and Tercel (88.7-93.5% and Stroby + Delan (77.9% and 82.1%. Our experiments showed that the investigated fungicide mixtures arehighly effective against V. inaqeulais, even under high disease pressure.

  8. Synthesis and Evaluation of Essential Oil-Derived β-Methoxyacrylate Derivatives as High Potential Fungicides

    Directory of Open Access Journals (Sweden)

    Haihuan Su

    2017-05-01

    Full Text Available Essential oils (EOs are plant-derived aroma compounds with a wide range of biological activity, but their actions are slow, and they are typically unstable to light or heat, difficult to extract and so on. To find highly potential fungicides derived from natural EOs, a series of essential oil-based β-methoxyacrylate derivatives have been designed and synthesized. The target compounds have been screened for their potential fungicidal activity against eleven species of plant pathogen fungi, including Alternaria alternata, Phomopsis adianticola, Pestalotiopsis theae, Sclerotinia sclerotiorum, etc. Compared with intermediates I, the parent essential oils and azoxystrobin, almost all of essential oil-based β-methoxyacrylate derivatives exhibited significantly better fungicidal activity. Further investigation revealed that some compounds showed remarkable inhibitory activities against Pestalotiopsis theae, Phomopsis adianticola, Sclerotinia sclerotiorum and Magnapothe grisea at different concentrations in contrast to the commercial product azoxystrobin. Compound II-8 exhibited particularly significant fungicidal activity.

  9. Gene Expression Profiling in Liver and Testis of Rats to Characterize the Toxicity of Triazole Fungicides

    Science.gov (United States)

    Four triazole fungicides were studied using toxicogenomic techniques to identify potential mechanisms of action. Adult male Sprague-Dawley rats were dosed for 14 days by gavage with fluconazole, myclobutanil, propiconazole, or triadimefon. Following exposure, serum was collected ...

  10. USING PHARMACOKINETIC DATA TO INTERPRET METABOLOMIC CHANGES IN CD-1 MICE TREATED WITH TRIAZOLE FUNGICIDES

    Science.gov (United States)

    Triazoles are a class of fungicides widely used in both pharmaceutical and agricultural applications. These compounds elicit a variety of toxic effects including disruption of normal metabolic processes such as steroidogenesis. Metabolomics is used to measure dynamic changes in e...

  11. Symptomatology of fungal competitors on oyster mushroom’s spawn packets and in vitro evaluation using phytoextracts and a fungicide

    Directory of Open Access Journals (Sweden)

    FA Shamoli

    2016-12-01

    Full Text Available An experiment was conducted to find out the fungal competitors and symptom studies in damaged Oyster Mushroom spawn packets at National Mushroom Development and Extension Center, Savar, Dhaka, Bangladesh. A total of nine fungal competitors of oyster mushroom were isolated and identified namely- Trichoderma harzianum Rifai, T. viride Pers. (Green strain, T. viride Pers. (Yellow strain, T. koningii Oudem, Mucor hiemalis Wehmer, Papulaspora byssina Hotson, Neurospora sp. Shear and B.O. Dodge., Aspergillus flavus Link., and Botryodiplodia theobromae Pat. on the basis of microscopic, morphological and cultural characteristics. To produce oyster mushroom in an eco-friendly manner and to find out their antifungal potency, 23 plant species belonging to 19 families were screened out against isolated nine fungal competitors of oyster mushroom. Among 23 extracts, the maximum (44% mycelial inhibition of T. harzianum was found due to Aegle marmelos whereas Eclipta alba showed the highest mycelial inhibition (62% of T. viride (Green strain; in case of T. viride (Yellow strain, Cassia tora exhibited the highest mycelial inhibition (39%; Diospyros cordifolia showed the maximum mycelial inhibition (48% of T. koningii; Curcuma longa (rhizome gave the maximum mycelial inhibition (90% of Neurospora sp. There were no significant effects found to control of P. byssina, B. theobromae, M. hiemalis and A. flavus due to 23 different types of botanicals tested. Trichoderma harzianum, T. viride (Green strain, T. viride (Yellow strain, T. koningii, A. flavus, Neurospora sp. and P. byssina was successfully inhibited by 30, 50 and 70 ppm of fungicide-Bavistin 50 WP but B. theobromae and M. hiemalis were not affected by Bavistin at mentioned concentration.

  12. Occurrence and persistence of fungicides in bed sediments and suspended solids from three targeted use areas in the United States

    Science.gov (United States)

    Smalling, Kelly L.; Reilly, Timothy J.; Sandstrom, Mark W.; Kuivila, Kathryn

    2013-01-01

    To document the environmental occurrence and persistence of fungicides, a robust and sensitive analytical method was used to measure 34 fungicides and an additional 57 current-use pesticides in bed sediments and suspended solids collected from areas of intense fungicide use within three geographic areas across the United States. Sampling sites were selected near or within agricultural research farms using prophylactic fungicides at rates and types typical of their geographic location. At least two fungicides were detected in 55% of the bed and 83% of the suspended solid samples and were detected in conjunction with herbicides and insecticides. Six fungicides were detected in all samples including pyraclostrobin (75%), boscalid (53%), chlorothalonil (41%) and zoxamide (22%). Pyraclostrobin, a strobilurin fungicide, used frequently in the United States on a variety of crops, was detected more frequently than p,p′-DDE, the primary degradate of p,p′-DDT, which is typically one of the most frequently occurring pesticides in sediments collected within highly agricultural areas. Maximum fungicide concentrations in bed sediments and suspended solids were 198 and 56.7 μg/kg dry weight, respectively. There is limited information on the occurrence, fate, and persistence of many fungicides in sediment and the environmental impacts are largely unknown. The results of this study indicate the importance of documenting the persistence of fungicides in the environment and the need for a better understanding of off-site transport mechanisms, particularly in areas where crops are grown that require frequent treatments to prevent fungal diseases.

  13. Avoidance behaviour and survival of two annelid oligochaetes exposed to two fungicides

    OpenAIRE

    Bart, Sylvain

    2016-01-01

    The use of pesticides in crop fields may have negative effects on soil biodiversity. Earthworms and enchytraeids are annelid oligochaetes involved in the evolution of soil organic matter and structure at different complementary scales. This study focused on the impact of two pesticides, an organic fungicide widely used to protect cereal crops in conventional agriculture and copper, a fungicide widely used in organic agriculture on fruit trees, vine or solanaceae to prevent spore germination. ...

  14. Effects of azole fungicides on the function of sex and thyroid hormones

    DEFF Research Database (Denmark)

    Kjærstad, Mia Birkhøj; Andersen, Helle Raun; Taxvig, Camilla

    Resumé: Azole-fungicides are frequently used in Denmark. Epoxiconazole, propiconazole, and tebuconazole had endocrine disrupting properties in cell based assays. In rats, epoxiconazole and tebuconazole increased gestational length, maternal progesterone level, and masculinized female-offspring. B......-offspring. Besides, tebuconazole caused feminization of male-offspring. Similar effects were previously demonstrated for prochloraz. The results indicate that azole-fungicides in general have endocrine disrupting properties...

  15. Nitroxide Tempol down-regulates kinase activities associated with NADPH oxidase function in phagocytic cells and potentially decreases their fungicidal response.

    Science.gov (United States)

    Santos, Gérsika B; Ribeiro, Ana C G; Lima, Samuel N P; Trostchansky, Andrés; Cerdeira, Cláudio Daniel; Brigagão, Maísa R P L

    2018-01-05

    The identification of novel targets to control inflammation in humans is probably the primary challenge that impairs the development of new anti-inflammatory drugs. Therefore, the modulation of intracellular signaling pathways in phagocytes may be an interesting means of achieving this goal. However, this change to signaling can compromise the host's susceptibility to invading pathogens. We investigated whether the antioxidant nitroxide Tempol regulates the activity of kinases associated with the production of oxidants in neutrophils, which affects the fungicidal capability of these cells. The effects of Tempol on PMA- or fMLP-activated neutrophils were examined by oxygen consumption as an index of the oxidative burst, a release of extracellular and total Reactive Oxygen Species (ROS) by chemiluminescence, kinase activities through analysis of ATP consumption during enzyme activities and the dot blot immunoassay and, finally, by neutrophil capacity of killing Candida albicans. Tempol significantly inhibited the neutrophil oxidative burst in a concentration-dependent manner and decreased oxygen consumption (IC50 = 45 μM) and extracellular/total ROS formation with an increase on the lag period response. In addition, Tempol inhibited neutrophil kinase activities (i.e., a decrease in protein phosphorylation) elicited through different biochemical pathways and consequently impaired the fungicidal activity of these cells. Although Tempol has potential anti-inflammatory activity that acts on different intracellular pathways (such as those involving kinases), researchers should be cautious, since this nitroxide down-regulated oxidants production and the fungicidal response of neutrophils. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. In vitro evaluation of biocontrol agents and fungicides on wood decay fungiganoderma associated with mortality of tree legumes

    Directory of Open Access Journals (Sweden)

    M Bhadra

    2016-12-01

    Full Text Available An experiment was conducted to isolate a number of biocontrol agent- Trichoderma spp. from infected spawn packets of oyster mushroom at National Mushroom Development and Extension Centre, Savar, Dhaka, Bangladesh. These bio-control agents were used as antagonist against four wild wood decay fungi of Ganoderma, viz., G. lucidum-1, G. lucidum-2, G. lucidum-3, G. applanatum and two cultivated G. lucidum-4, G.lucidum-6 under in vitro condition. An in vitro trial of Trichoderma spp. against Ganoderma were performed by dual culture, by treating with volatile, non-volatile and naturally untreated metabolites of bio-control agents. In dual culture, all the Trichoderma species showed 70- 100% mycelia inhibition of G. lucidum-1 and G. lucidum-2, 55.6-100% inhibition of G. lucidum-3, 20-66.7% of G. applanatum, 100% of G. lucidum-5, 75-100% of G. lucidum-6. Effects of heat killed extracts of Trichoderma spp. on growth of G. lucidum-2 (wild and G. lucidum-6 (cultivated were also evaluated. Fungicides Bavistin and Dithane M-45 were also used to investigate the mycelial growth inhibition of Ganoderma spp.

  17. Inhibition of Fungal Aflatoxin B1 Biosynthesis by Diverse Botanically ...

    African Journals Online (AJOL)

    School of Food Science, Henan Institute of Science and Technology, Xinxiang 453003, China ... As a globally-consumed beverage, tea contains ..... 19. U.S. Department of Agriculture, Agricultural Research. Service. 2011. USDA Database for the Flavonoid. Content of Selected Foods, Release 3.0. Nutrient. Data Laboratory ...

  18. Effects of Fungicide Treatment on Free Amino Acid Concentration and Acrylamide-Forming Potential in Wheat.

    Science.gov (United States)

    Curtis, Tanya Y; Powers, Stephen J; Halford, Nigel G

    2016-12-28

    Acrylamide forms from free asparagine and reducing sugars during frying, baking, roasting, or high-temperature processing, and cereal products are major contributors to dietary acrylamide intake. Free asparagine concentration is the determining factor for acrylamide-forming potential in cereals, and this study investigated the effect of fungicide application on free asparagine accumulation in wheat grain. Free amino acid concentrations were measured in flour from 47 varieties of wheat grown in a field trial in 2011-2012. The wheat had been supplied with nitrogen and sulfur and treated with growth regulators and fungicides. Acrylamide formation was measured after the flour had been heated at 180 °C for 20 min. Flour was also analyzed from 24 (of the 47) varieties grown in adjacent plots that were treated in identical fashion except that no fungicide was applied, resulting in visible infection by Septoria tritici, yellow rust, and brown rust. Free asparagine concentration in the fungicide-treated wheat ranged from 1.596 to 3.987 mmol kg -1 , with a significant (p fungicide treatment, the increases in acrylamide ranging from 2.7 to 370%. Free aspartic acid concentration also increased, whereas free glutamic acid concentration increased in some varieties but decreased in others, and free proline concentration decreased. The study showed disease control by fungicide application to be an important crop management measure for mitigating the problem of acrylamide formation in wheat products.

  19. Control Efficacy of Fungicide Injection on Oak Wilt in the Field

    Directory of Open Access Journals (Sweden)

    Su-Yeon Son

    2014-12-01

    Full Text Available Oak wilt caused by Raffaelea quercus-mongolicae was first noticed in South Korea in 2004 and, ever since, its distribution and damage have been increasing. To screen a fungicide effective for oak wilt control by tree injection, laboratory and field experiments were conducted. Ten fungicides and one antibiotic were examined in vivo for their effectiveness in restricting the growth of R. quercus-mongolicae and R. quercivora (Japanese oak wilt pathogen isolates. To the Korean isolates of R. quercus-mongolicae, chlorothalonil showed the highest fungicidal effects, followed by benomyl and propiconazole. To the Japanese one, propiconazole was highest in the fungicidal effectiveness, followed by benomyl and bitertanol. Propiconazole was selected for field-testing of its control efficacy because it showed good fungicidal effects in vitro and systemic activity. The control efficacy in the field was 87.5% in the first year of injection and 66.7% in the second year, indicating the fungicidal effects last at least over one year.

  20. New α-Methylene-γ-Butyrolactone Derivatives as Potential Fungicidal Agents: Design, Synthesis and Antifungal Activities

    Directory of Open Access Journals (Sweden)

    Yongling Wu

    2016-01-01

    Full Text Available In consideration of the fact that the α-methylene-γ-butyrolactone moiety is a major bio-functional group in the structure of carabrone and possesses some agricultural biological activity, forty-six new ester and six new ether derivatives containing α-methylene-γ-butyrolactone moieties were synthesized, and their fungicidal activities against Colletotrichum lagenarium and Botrytis cinerea were investigated. Most of the synthesized compounds showed moderate to significant fungicidal activity. Among them, halogen atom-containing derivatives showed better activity than others, especially compounds 6a,d which exhibited excellent fungicidal activity against C. lagenarium, with IC50 values of 7.68 and 8.17 μM. The structure-activity relationship (SAR analysis indicated that ester derivatives with electron-withdrawing groups on the benzene ring showed better fungicidal activity than those with electron-donating groups. A quantitative structure-activity relationship (QSAR model (R2 = 0.9824, F = 203.01, S2 = 0.0083 was obtained through the heuristic method. The built model revealed a strong correlation of fungicidal activity against C. lagenarium with the molecular structures of these compounds. These results are expected to prove helpful in the design and exploration of low toxicity and high efficiency α-methylene-γ-butyrolactone-based fungicides.

  1. Assessing the impact of fungicide enostroburin application on bacterial community in wheat phyllosphere.

    Science.gov (United States)

    Gu, Likun; Bai, Zhihui; Jin, Bo; Hu, Qing; Wang, Huili; Zhuang, Guoqiang; Zhang, Hongxun

    2010-01-01

    Fungicides have been used extensively for controlling fungal pathogens of plants. However, little is known regarding the effects that fungicides upon the indigenous bacterial communities within the plant phyllosphere. The aims of this study were to assess the impact of fungicide enostroburin upon bacterial communities in wheat phyllosphere. Culture-independent methodologies of 16S rDNA clone library and 16S rDNA directed polymerase chain reaction with denaturing gradient gel electrophoresis (PCR-DGGE) were used for monitoring the change of bacterial community. The 16S rDNA clone library and PCR-DGGE analysis both confirmed the microbial community of wheat plant phyllosphere were predominantly of the gamma-Proteobacteria phyla. Results from PCR-DGGE analysis indicated a significant change in bacterial community structure within the phyllosphere following fungicide enostroburin application. Bands sequenced within control cultures were predominantly of Pseudomonas genus, but those bands sequenced in the treated samples were predominantly strains of Pantoea genus and Pseudomonas genus. Of interest was the appearance of two DGGE bands following fungicide treatment, one of which had sequence similarities (98%) to Pantoea sp. which might be a competitor of plant pathogens. This study revealed the wheat phyllosphere bacterial community composition and a shift in the bacterial community following fungicide enostroburin application.

  2. GROWTH RETARDANTS: Effects on Gibberellin Biosynthesis and Other Metabolic Pathways.

    Science.gov (United States)

    Rademacher, Wilhelm

    2000-06-01

    Plant growth retardants are applied in agronomic and horticultural crops to reduce unwanted longitudinal shoot growth without lowering plant productivity. Most growth retardants act by inhibiting gibberellin (GA) biosynthesis. To date, four different types of such inhibitors are known: (a) Onium compounds, such as chlormequat chloride, mepiquat chloride, chlorphonium, and AMO-1618, which block the cyclases copalyl-diphosphate synthase and ent-kaurene synthase involved in the early steps of GA metabolism. (b) Compounds with an N-containing heterocycle, e.g. ancymidol, flurprimidol, tetcyclacis, paclobutrazol, uniconazole-P, and inabenfide. These retardants block cytochrome P450-dependent monooxygenases, thereby inhibiting oxidation of ent-kaurene into ent-kaurenoic acid. (c) Structural mimics of 2-oxoglutaric acid, which is the co-substrate of dioxygenases that catalyze late steps of GA formation. Acylcyclohexanediones, e.g. prohexadione-Ca and trinexapac-ethyl and daminozide, block particularly 3ss-hydroxylation, thereby inhibiting the formation of highly active GAs from inactive precursors, and (d) 16,17-Dihydro-GA5 and related structures act most likely by mimicking the GA precursor substrate of the same dioxygenases. Enzymes, similar to the ones involved in GA biosynthesis, are also of importance in the formation of abscisic acid, ethylene, sterols, flavonoids, and other plant constituents. Changes in the levels of these compounds found after treatment with growth retardants can mostly be explained by side activities on such enzymes.

  3. Glyoxal bis(guanylhydrazone) as an inhibitor of polyamine biosynthesis in tumour cells.

    OpenAIRE

    Seppänen, P; Fagerström, R; Alhonen-Hongisto, L; Elo, H; Lumme, P; Jänne, J

    1984-01-01

    Glyoxal bis(guanylhydrazone), the parent compound of methylglyoxal bis(guanylhydrazone), was synthesized and tested for its ability to inhibit the biosynthesis of polyamines. It was found to be a powerful competitive inhibitor of adenosylmethionine decarboxylase (EC 4.1.1.50), yet the lack of the methyl group at the glyoxal portion increased the apparent Ki value for the enzyme by about 30-fold in comparison with methylglyoxal bis(guanylhydrazone). Glyoxal bis(guanylhydrazone) inhibited diami...

  4. Design, synthesis, and fungicidal activity of novel carboxylic acid amides represented by N-benzhydryl valinamode carbamates.

    Science.gov (United States)

    Du, Xiu-Jiang; Bian, Qiang; Wang, Hong-Xue; Yu, Shu-Jing; Kou, Jun-Jie; Wang, Zhi-Peng; Li, Zheng-Ming; Zhao, Wei-Guang

    2014-08-07

    Carboxylic acid amide (CAA) fungicides are an important class of agricultural fungicide with oomycete activity and low toxicity toward mammalian cells. To find CAA analogues with high activity against resistant pathogens, a series of substituted N-benzhydryl valinamide carbamate derivatives were designed and synthesized by introducing substituted aromatic rings into valinamide carbamate leads. Bioassays showed that some title compounds exhibited very good in vitro fungicidal activity against Phytophthora capsici and in vivo fungicidal activities against Pseudoperonospora cubensis. Topomer CoMFA was performed to explore the structure-activity relationship on the basis of the in vitro data. The dimethoxy substituted aromatic analogue 9e was found to display higher in vitro fungicidal activity against Phytophthora capsici than iprovalicarb but lower activity than mandipropamid, and higher in vivo fungicidal activity against Pseudoperonospora cubensis than dimethomorph at a dosage of 6.25 μg mL(-1).

  5. Photoreduction of chlorothalonil fungicide on plant leaf models.

    Science.gov (United States)

    Monadjemi, S; El Roz, M; Richard, C; Ter Halle, A

    2011-11-15

    Photodegradation is seldom considered at the surface of vegetation after crop spraying. Chlorothalonil, a broad-spectrum foliar fungicide with a very widespread use worldwide, was considered. To represent the waxy upper layer of leaves, tests were performed within thin paraffin wax films or in n-heptane. Laser flash photolysis together with steady-state irradiation in n-heptane allowed the determination of the photodegradation mechanisms Chlorothalonil ability to produce singlet oxygen was measured; noteworthy its efficiency is close to 100%. Additionally, chlorothalonil photodegradation mainly proceeds through reductive dechlorination. In these hydrophobic media, a radical mechanism was evidenced. Photochemical tests on wax films under simulated solar light show that formulated chlorothalonil is more reactive than pure chlorothalonil. The field-extrapolated half-life of photolysis on vegetation was estimated to 5.3 days. This value was compared to the half-lives of penetration and volatilization available in the literature. It appears that chlorothalonil dissipation from crops is ruled by both photodegradation and penetration. The relative importance of the two paths probably depends on meteorological factors and on physicochemical characteristics of the crop leaf cuticle.

  6. Dissipation of the fungicide hexaconazole in oil palm plantation.

    Science.gov (United States)

    Maznah, Zainol; Halimah, Muhamad; Ismail, Sahid; Idris, Abu Seman

    2015-12-01

    Hexaconazole is a potential fungicide to be used in the oil palm plantation for controlling the basal stem root (BSR) disease caused by Ganoderma boninense. Therefore, the dissipation rate of hexaconazole in an oil palm agroecosystem under field conditions was studied. Two experimental plots were treated with hexaconazole at the recommended dosage of 4.5 g a.i. palm(-1) (active ingredient) and at double the recommended dosage (9.0 g a.i. palm(-1)), whilst one plot was untreated as control. The residue of hexaconazole was detected in soil samples in the range of 2.74 to 0.78 and 7.13 to 1.66 mg kg(-1) at the recommended and double recommended dosage plots, respectively. An initial relatively rapid dissipation rate of hexaconazole residues occurred but reduced with time. The dissipation of hexaconazole in soil was described using first-order kinetics with the value of coefficient regression (r (2) > 0.8). The results indicated that hexaconazole has moderate persistence in the soil and the half-life was found to be 69.3 and 86.6 days in the recommended and double recommended dosage plot, respectively. The results obtained highlight that downward movement of hexaconazole was led by preferential flow as shown in image analysis. It can be concluded that varying soil conditions, environmental factors, and pesticide chemical properties of hexaconazole has a significant impact on dissipation of hexaconazole in soil under humid conditions.

  7. Interactions among cooling, fungicide and postharvest ripening temperature on peaches

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Trujillo, J. Pablo; Cano, Antonio; Artes, Francisco [Postharvest and refrigeration Lab., Dept. of Food Science and Technology, CEBAS-CSIC, Murcia (Spain)

    2000-07-01

    Peach fruit (Prunus persica L. cv. 'Miraflores') harvested at the firm-ripe stage, treated or not with 2 g l{sup -1} iprodione, were cooled or not at 1{sup o}C and ripened at 15 or 20{sup o}C and 95% RH for 10 days. During ripening, weight loss, fungal development and changes in quality parameters (firmness, soluble solids content, titratable acidity, pH and ground and flesh color), and carbon dioxide and ethylene production were monitored. Cooling alone or combined with iprodione avoided Rhizopus nigricans decay during ripening at either ripening temperatures. A skin damage not previously reported on fungicide treated peach was observed at 20{sup o}C. Cooled fruit ripened at 15{sup o}C showed an anomalous respiration rate and ethylene production after the climacteric peak, a loss of firmness and a drop in titratable acidity after 7 days of storage, and reduced endo-polygalacturonase activity in presence of continuous pectinmethylesterase activity during the first week. Cooling before ripening at 20{sup o}C led to the best flavor without excessive total losses. These results helped in the optimization of warming cycles during cold storage used to avoid chilling injuries development on peaches. (Author)

  8. Immunomodulatory effects of the fungicide Mancozeb in agricultural workers

    International Nuclear Information System (INIS)

    Corsini, Emanuela; Birindelli, Sarah; Fustinoni, Silvia; De Paschale, Gioia; Mammone, Teresa; Visentin, Sara; Galli, Corrado L.; Marinovich, Marina; Colosio, Claudio

    2005-01-01

    Available data suggest that ethylenebisdithiocarbamates (EBDCs) may have immunomodulatory effects. This study aimed to investigate the immunological profile of farmers exposed to Mancozeb, an EBDC fungicide, through the determination of several serum, cellular, and functional immune parameters. Twenty-six healthy subjects entered the study, 13 vineyards exposed to Mancozeb and 13 unexposed controls. Exposure was assessed through the determination of ethylentiourea (ETU) in urine. Complete and differential blood count, serum immunoglobulins, complement fractions, autoantibodies, lymphocyte subpopulations, proliferative response to mitogens, natural killer (NK) activity, and cytokine production were measured. Post-exposure samples showed ETU urine concentration significantly higher than pre-exposure and control groups. A significant increase in CD19+ cells, both percentage and absolute number, and a significant decrease in the percentage of CD25+ cells were found in post-exposure samples compared to controls. A statistically significant increase in the proliferative response to phorbol myristate acetate plus ionomycin (PMA + ionomycin) was observed in the post-exposure group compared to controls and baseline, while a significant reduction in LPS-induced TNF-α release in post-exposure samples was observed. Overall, our results suggest that low-level exposure to Mancozeb has slight immunomodulatory effects, and point out a method adequate to reveal immune-modifications in workers occupationally exposed to potential immunotoxic compounds, based on a whole blood assay

  9. Glycoprotein biosynthesis by human normal platelets

    International Nuclear Information System (INIS)

    Rodriguez, P.; Bello, O.; Apitz-Castro, R.

    1987-01-01

    Incorporation of radioactive Man, Gal, Fuc, Glc-N, and NANA into washed human normal platelets and endogenous glycoproteins has been found. Both parameters were time dependent. Analysis of hydrolyzed labeled glycoproteins by paper chromatography revealed that the radioactive monosaccharide incubated with the platelets had not been converted into other sugars. Acid hydrolysis demonstrates the presence of a glycosidic linkage. All the effort directed to the demonstration of the existence of a lipid-sugar intermediate in intact human platelets yielded negative results for Man and Glc-N used as precursors. The incorporation of these sugars into glycoproteins is insensitive to bacitracin, suggesting no involvement of lipid-linked saccharides in the synthesis of glycoproteins in human blood platelets. The absence of inhibition of the glycosylation process in the presence of cycloheximide suggests that the sugars are added to proteins present in the intact platelets. These results support the contention that glycoprotein biosynthesis in human blood platelets observed under our experimental conditions is effected through direct sugar nucleotide glycosylation

  10. Hexadecylphosphocholine (miltefosine) has broad-spectrum fungicidal activity and is efficacious in a mouse model of cryptococcosis.

    Science.gov (United States)

    Widmer, Fred; Wright, Lesley C; Obando, Daniel; Handke, Rosemary; Ganendren, Ranjini; Ellis, David H; Sorrell, Tania C

    2006-02-01

    The alkyl phosphocholine drug miltefosine is structurally similar to natural substrates of the fungal virulence determinant phospholipase B1 (PLB1), which is a potential drug target. We determined the MICs of miltefosine against key fungal pathogens, correlated antifungal activity with inhibition of the PLB1 activities (PLB, lysophospholipase [LPL], and lysophospholipase-transacylase [LPTA]), and investigated its efficacy in a mouse model of disseminated cryptococcosis. Miltefosine inhibited secreted cryptococcal LPTA activity by 35% at the subhemolytic concentration of 25 microM (10.2 microg/ml) and was inactive against mammalian pancreatic phospholipase A2 (PLA2). At 250 microM, cytosolic PLB, LPL, and LPTA activities were inhibited by 25%, 51%, and 77%, respectively. The MICs at which 90% of isolates were inhibited (MIC90s) against Candida albicans, Candida glabrata, Candida krusei, Cryptococcus neoformans, Cryptococcus gattii, Aspergillus fumigatus, Fusarium solani, Scedosporium prolificans, and Scedosporium apiospermum were 2 to 4 microg/ml. The MICs of miltefosine against Candida tropicalis (n = 8) were 2 to 4 microg/ml, those against Aspergillus terreus and Candida parapsilosis were 8 microg/ml (MIC90), and those against Aspergillus flavus (n = 8) were 2 to 16 microg/ml. Miltefosine was fungicidal for C. neoformans, with rates of killing of 2 log units within 4 h at 7.0 microM (2.8 microg/ml). Miltefosine given orally to mice on days 1 to 5 after intravenous infection with C. neoformans delayed the development of illness and mortality and significantly reduced the brain cryptococcal burden. We conclude that miltefosine has broad-spectrum antifungal activity and is active in vivo in a mouse model of disseminated cryptococcosis. The relatively small inhibitory effect on PLB1 enzyme activities at concentrations exceeding the MIC by 2 to 20 times suggests that PLB1 inhibition is not the only mechanism of the antifungal effect.

  11. Influence of caffeine and hyaluronic acid on collagen biosynthesis in human skin fibroblasts

    Directory of Open Access Journals (Sweden)

    Donejko M

    2014-10-01

    Full Text Available Magdalena Donejko,1 Andrzej Przylipiak,1 Edyta Rysiak,2 Katarzyna Głuszuk,2 Arkadiusz Surażyński2 1Department of Esthetic Medicine, 2Department of Medicinal Chemistry, Faculty of Pharmacy, Medical University of Białystok, Białystok, Poland Aim: The aim of this study was to evaluate the effect of caffeine on collagen biosynthesis in human skin fibroblasts and the influence of hyaluronic acid (HA on this process. Materials and methods: Collagen, [3H]-thymidine incorporation, and prolidase activity were measured in confluent human skin fibroblast cultures that had been treated with 1, 2, and 5 mM caffeine and with caffeine and 500 µg/mL HA. Western immunoblot analysis was performed to evaluate expression of ß1-integrin receptor, insulin-like growth factor receptor phospho-Akt protein and mitogen-activated protein kinase (phospho-extracellular signal-regulated kinase. Results: Caffeine inhibited collagen biosynthesis in a dose-dependent manner. The mechanism of this process was found at the level of prolidase activity. Caffeine significantly inhibited the enzyme activity. The addition of HA had no effect on collagen biosynthesis or prolidase activity in fibroblasts incubated with caffeine. Caffeine also had an inhibitory effect on DNA biosynthesis. HA, however, did not have any significant effect on this process. The inhibition of the expression of ß1-integrin and insulin-like growth factor receptor in fibroblasts incubated with the caffeine indicates a possible mechanism of inhibition of collagen biosynthesis. Conclusion: Caffeine reduces collagen synthesis in human cultured skin fibroblasts. HA did not have any significant protective effect on this process. This is the first study to our knowledge that reports caffeine-induced inhibition of collagen synthesis in human skin fibroblasts. Keywords: collagen, caffeine, hyaluronic acid, fibroblast

  12. Dithiolopyrrolone Natural Products: Isolation, Synthesis and Biosynthesis

    Science.gov (United States)

    Qin, Zhiwei; Huang, Sheng; Yu, Yi; Deng, Hai

    2013-01-01

    Dithiolopyrrolones are a class of antibiotics that possess the unique pyrrolinonodithiole (4H-[1,2] dithiolo [4,3-b] pyrrol-5-one) skeleton linked to two variable acyl groups. To date, there are approximately 30 naturally occurring dithiolopyrrolone compounds, including holomycin, thiolutin, and aureothricin, and more recently thiomarinols, a unique class of hybrid marine bacterial natural products containing a dithiolopyrrolone framework linked by an amide bridge with an 8-hydroxyoctanoyl chain linked to a monic acid. Generally, dithiolopyrrolone antibiotics have broad-spectrum antibacterial activity against various microorganisms, including Gram-positive and Gram-negative bacteria, and even parasites. Holomycin appeared to be active against rifamycin-resistant bacteria and also inhibit the growth of the clinical pathogen methicillin-resistant Staphylococcus aureus N315. Its mode of action is believed to inhibit RNA synthesis although the exact mechanism has yet to be established in vitro. A recent work demonstrated that the fish pathogen Yersinia ruckeri employs an RNA methyltransferase for self-resistance during the holomycin production. Moreover, some dithiolopyrrolone derivatives have demonstrated promising antitumor activities. The biosynthetic gene clusters of holomycin have recently been identified in S. clavuligerus and characterized biochemically and genetically. The biosynthetic gene cluster of thiomarinol was also identified from the marine bacterium Pseudoalteromonas sp. SANK 73390, which was uniquely encoded by two independent pathways for pseudomonic acid and pyrrothine in a novel plasmid. The aim of this review is to give an overview about the isolations, characterizations, synthesis, biosynthesis, bioactivities and mode of action of this unique family of dithiolopyrrolone natural products, focusing on the period from 1940s until now. PMID:24141227

  13. Vitamin B biosynthesis in plants.

    Science.gov (United States)

    Roje, Sanja

    2007-07-01

    The vitamin B complex comprises water-soluble enzyme cofactors and their derivatives that are essential contributors to diverse metabolic processes in plants as well as in animals and microorganisms. Seven vitamins form this complex: B1 (thiamin (1)), B2 (riboflavin (2)), B3 (niacin (3)), B5 (pantothenic acid (4)), B6 (pyridoxine, pyridoxal (5), and pyridoxamine), B8 (biotin (6)), and B9 (folate (7)). All seven B vitamins are required in the human diet for proper nutrition because humans lack enzymes to synthesize these compounds de novo. This review aims to summarize the present knowledge of vitamin B biosynthesis in plants.

  14. In vitro metabolism of the anti-androgenic fungicide vinclozolin by rat liver microsomes.

    Science.gov (United States)

    Sierra-Santoyo, Adolfo; Angeles-Soto, Esperanza; de Lourdes López-González, Ma; Harrison, Randy A; Hughes, Michael F

    2012-03-01

    Vinclozolin (V) is a fungicide used in agricultural settings. V administered to rats is hydrolyzed to 2-[[(3,5-dichlorophenyl)-carbamoyl]oxy]-2-methyl-3-butenoic acid (M1) and 3',5'-dichloro-2-hydroxy-2-methylbut-3-enanilide (M2). V, M1 and M2 have antiandrogenic properties by interacting with the androgen receptor. Data on V, M1 and M2 biotransformation are limited. Our objective was to characterize V metabolism by rat liver microsomes. V was incubated with non-treated adult male Long-Evans rat liver microsomes and NADPH. Several metabolites were detected following the extraction of incubate with acetonitrile and analysis by HPLC/DAD/MSD. One metabolite was identified as [3-(3,5-dichlorophenyl)-5-methyl-5-(1,2-dihydroxyethyl)-1,3-oxazolidine-2,4-dione] (M4), which was gradually converted to 3',5'-dichloro-2,3,4-trihydroxy-2-methylbutylanilide (M5). Both co-eluted in the same HPLC peak. Another metabolite ([M7]) was detected by UV but was unstable for mass spectral analysis. The K(M app) for co-eluted M4/M5 and [M7] was 53.7 and 135.4 μM, the V(max app) was 0.812 and 0.669 nmoles/min/mg protein, and CL(int) was 15.1 and 4.9 ml/min/g protein, respectively. Pilocarpine, orphenadrine and proadifen and anti-rat cytochrome P450 (CYP)2A, 2B and 3A antibodies inhibited M4/M5 and [M7] formation. These results indicate that V is efficiently metabolized by CYP. Determination of the metabolites of V will provide further insight into the relationship between toxicity and tissue dose of V and its metabolites.

  15. Mechanisms of action underlying the antiandrogenic effects of the fungicide prochloraz

    International Nuclear Information System (INIS)

    Laier, Peter; Metzdorff, Stine Broeng; Borch, Julie; Hagen, Marie Louise; Hass, Ulla; Christiansen, Sofie; Axelstad, Marta; Kledal, Thuri; Dalgaard, Majken; McKinnell, Chris; Brokken, Leon J.S.; Vinggaard, Anne Marie

    2006-01-01

    The fungicide prochloraz has got multiple mechanisms of action that may influence the demasculinizing and reproductive toxic effects of the compound. In the present study, Wistar rats were dosed perinatally with prochloraz (50 and 150 mg/kg/day) from gestational day (GD) 7 to postnatal day (PND) 16. Caesarian sections were performed on selected dams at GD 21, while others were allowed to give birth to pups that were followed until PND 16. Prochloraz caused mild dysgenesis of the male external genitalia as well as reduced anogenital distance and retention of nipples in male pups. An increased anogenital distance indicated virilization of female pups. Effects on steroidogenesis in male fetuses became evident as decreased testicular and plasma levels of testosterone and increased levels of progesterone. Ex vivo synthesis of both steroid hormones was qualitatively similarly affected by prochloraz. Immunohistochemistry of fetal testes showed increased expression of 17α-hydroxylase/17,20-lyase (P450c17) and a reduction in 17β-hydroxysteroid dehydrogenase (type 10) expression, whereas no changes in expression of genes involved in testicular steroidogenesis were observed. Increased expression of P450c17 mRNA was observed in fetal male adrenals, and the androgen-regulated genes ornithine decarboxylase, prostatic binding protein C3 as well as insulin-like growth factor I mRNA were reduced in ventral prostates PND 16. These results indicate that reduced activity of P450c17 may be a primary cause of the disrupted fetal steroidogenesis and that an altered androgen metabolism may play a role as well. In vitro studies on human adrenocortical carcinoma cells supported the findings in vivo as reduced testosterone and increased progesterone levels were observed. Overall, these results together indicate that prochloraz acts directly on the fetal testis to inhibit steroidogenesis and that this effect is exhibited at protein, and not at genomic, level

  16. A Major Facilitator Superfamily Transporter-Mediated Resistance to Oxidative Stress and Fungicides Requires Yap1, Skn7, and MAP Kinases in the Citrus Fungal Pathogen Alternaria alternata.

    Directory of Open Access Journals (Sweden)

    Li-Hung Chen

    Full Text Available Major Facilitator Superfamily (MFS transporters play an important role in multidrug resistance in fungi. We report an AaMFS19 gene encoding a MFS transporter required for cellular resistance to oxidative stress and fungicides in the phytopathogenic fungus Alternaria alternata. AaMFS19, containing 12 transmembrane domains, displays activity toward a broad range of substrates. Fungal mutants lacking AaMFS19 display profound hypersensitivities to cumyl hydroperoxide, potassium superoxide, many singlet oxygen-generating compounds (eosin Y, rose Bengal, hematoporphyrin, methylene blue, and cercosporin, and the cell wall biosynthesis inhibitor, Congo red. AaMFS19 mutants also increase sensitivity to copper ions, clotrimazole, fludioxonil, and kocide fungicides, 2-chloro-5-hydroxypyridine (CHP, and 2,3,5-triiodobenzoic acid (TIBA. AaMFS19 mutants induce smaller necrotic lesions on leaves of a susceptible citrus cultivar. All observed phenotypes in the mutant are restored by introducing and expressing a wild-type copy of AaMFS19. The wild-type strain of A. alternata treated with either CHP or TIBA reduces radial growth and formation and germination of conidia, increases hyphal branching, and results in decreased expression of the AaMFS19 gene. The expression of AaMFS19 is regulated by the Yap1 transcription activator, the Hog1 and Fus3 mitogen-activated protein (MAP kinases, the 'two component' histidine kinase, and the Skn7 response regulator. Our results demonstrate that A. alternata confers resistance to different chemicals via a membrane-bound MFS transporter.

  17. Biosynthesis of bacterial aromatic polyketides.

    Science.gov (United States)

    Zhan, Jixun

    2009-01-01

    Aromatic polyketides represent important members of the family of polyketides, which have displayed a wide assortment of bioactive properties, such as antibacterial, antitumor, and antiviral activities. Bacterial aromatic polyketides are mainly synthesized by type II polyketide synthases (PKSs). Whereas malonyl-CoA is exclusively used as the extender unit, starter units can vary in different aromatic polyketide biosynthetic pathways, leading to a variety of polyketide backbones. Once the polyketide chains are elongated by the minimal PKSs to the full length, the immediate tailoring enzymes including ketoreductases, oxygenases and cyclases will work on the nascent chains to form aromatic structures, which will be further decorated by those late tailoring enzymes such as methyltransferases and glycosyltransferases. The mechanistic studies on the biosynthetic pathways of aromatic polyketides such as oxytetracycline and pradimicin A have been extensively carried out in recent years. Engineered biosynthesis of novel "unnatural" polyketides has been achieved in heterologous hosts such as Streptomyces coelicolor and Escherichia coli. This review covers the most recent advances in aromatic polyketide biosynthesis, which provide new enzymes or methods for building novel polyketide biosynthetic machinery.

  18. Fatty acid biosynthesis in actinomycetes

    Science.gov (United States)

    Gago, Gabriela; Diacovich, Lautaro; Arabolaza, Ana; Tsai, Shiou-Chuan; Gramajo, Hugo

    2011-01-01

    All organisms that produce fatty acids do so via a repeated cycle of reactions. In mammals and other animals, these reactions are catalyzed by a type I fatty acid synthase (FAS), a large multifunctional protein to which the growing chain is covalently attached. In contrast, most bacteria (and plants) contain a type II system in which each reaction is catalyzed by a discrete protein. The pathway of fatty acid biosynthesis in Escherichia coli is well established and has provided a foundation for elucidating the type II FAS pathways in other bacteria (White et al., 2005). However, fatty acid biosynthesis is more diverse in the phylum Actinobacteria: Mycobacterium, possess both FAS systems while Streptomyces species have only the multi-enzyme FAS II system and Corynebacterium species exclusively FAS I. In this review we present an overview of the genome organization, biochemical properties and physiological relevance of the two FAS systems in the three genera of actinomycetes mentioned above. We also address in detail the biochemical and structural properties of the acyl-CoA carboxylases (ACCases) that catalyzes the first committed step of fatty acid synthesis in actinomycetes, and discuss the molecular bases of their substrate specificity and the structure-based identification of new ACCase inhibitors with anti-mycobacterial properties. PMID:21204864

  19. In vitro and in vivo inhibitory effects of some fungicides on catalase produced and purified from white-rot fungus Phanerochaete chrysosporium.

    Science.gov (United States)

    Kavakçıoğlu, Berna; Tarhan, Leman

    2014-10-01

    In this study, in vitro and in vivo effects of some commonly used fungicides, antibiotics, and various chemicals on isolated and purified catalase from Phanerochaete chrysosporium were investigated. The catalase was purified 129.10-fold by using 60% ammonium sulfate and 60% ethanol precipitations, DEAE-cellulose anion exchange and Sephacryl-S-200 gel filtration chromatographies from P. chrysosporium growth in carbon- and nitrogen-limited medium for 12 days. The molecular weight of native purified catalase from P. chrysosporium was found to be 290 ± 10 kDa, and sodium dodecyl sulfate (SDS)-PAGE results indicated that enzyme consisted of four apparently identical subunits, with a molecular weight of 72.5 ± 2.5 kDa. Kinetic characterization studies showed that optimum pH and temperature, Km and Vmax values of the purified catalase which were stable in basic region and at comparatively high temperatures were 7.5, 30°C, 289.86 mM, and 250,000 U/mg, respectively. The activity of purified catalase from P. chrysosporium was significantly inhibited by dithiothreitol (DTT), 2-mercaptoethanol, iodoacetamide, EDTA, and sodium dodecyl sulfate (SDS). It was found that while antibiotics had no inhibitory effects, 45 ppm benomyl, 144 ppm captan, and 47.5 ppm chlorothalonil caused 14.52, 10.82, and 38.86% inhibition of purified catalase, respectively. The inhibition types of these three fungicides were found to be non-competitive inhibition with the Ki values of 1.158, 0.638, and 0.145 mM and IC50 values of 0.573, 0.158, 0.010 mM, respectively. The results of in vivo experiments also showed that benomyl, captan and chlorothalonil caused 15.25, 1.96, and 36.70% activity decreases after 24-h treatments compared to that of the control.

  20. Surfactin – A Review on Biosynthesis, Fermentation, Purification and Applications

    Directory of Open Access Journals (Sweden)

    Nikhil S. Shaligram

    2010-01-01

    Full Text Available Surfactin, a bacterial cyclic lipopeptide, is produced by various strains of Bacillus subtilis and is primarily recognized as one of the most effective biosurfactants. It has the ability to reduce surface tension of water from 72 to 27 mN/m at a concentration as low as 0.005 %. The structure of surfactin consists of seven amino acids bonded to the carboxyl and hydroxyl groups of a 14-carbon fatty acid. Surfactin possesses a number of biological activities such as the ability to lyse erythrocytes, inhibit clot formation, lyse bacterial spheroplasts and protoplasts, and inhibit cyclic 3',5-monophosphate diesterase. The high cost of production and low yields have limited its use in various commercial applications. Both submerged and solid-state fermentation have been investigated with the mutational approach to improve the productivity. In this review, current state of knowledge on biosynthesis of surfactin, its fermentative production, purification, analytical methods and biomedical applications is presented.

  1. Control of Fusarium head blight of winter wheat by artificial and natural infection using new fungicides

    Directory of Open Access Journals (Sweden)

    Olga Treikale

    2012-12-01

    Full Text Available In Latvia, climatic factors are influential in spreading of Fusarium head blight of cereals caused by Fusarium species. The most significant factor affecting the incidence of the disease in winter wheat is hightened temperature at the time of wheat anthesis. Field trials for the control of the disease in winter wheat were done in 2003-2004 using new fungicides applied at various rates by natural infection and artificial inoculation. Three species of causative agents: Fusarium avenaceum var. herbarum, F. gibbosum, F. culmorum were collected from infected seeds of wheat and used for inoculation of experimental plots at the concentration 106 conidia ml-1 (1:1:1 at the stage of full anthesis. Effective control of the disease was obtained through application of new fungicides with different active ingredient: Prosaro 250 EC (tebuconazole 125 G, prothioconazole 125 G L-1, Input 460 EC (spiroxamine 300 G, prothioconazole 160 G L-1. In conditions of artificial infection by severe attack of Fusarium spp. the application of fungicides containing tebuconazole at T3 gave significant influence on yield of winter wheat through plumpness of grains increase. High efficacy of fungicides against leaf infection with Erysiphe graminis and Drechslera tritici-repentis was also in the trial achieved. Application of fungicide containing cyproconazole and trifloxystrobin at T1 in the trial 2004 gave good control of Septoria tritici, E. graminis and D. triticirepentis.

  2. Compatibility of insecticides and fungicides with the zoophytophagous mirid predator Nesidiocoris tenuis.

    Science.gov (United States)

    Ziaei Madbouni, Mohammad Ali; Samih, Mohammad Amin; Qureshi, Jawwad A; Biondi, Antonio; Namvar, Peyman

    2017-01-01

    Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) is an effective predator of multiple pests of vegetable crops, such as thrips, mites, aphids, whiteflies, leafminers. It is mass-reared and released for augmentative biocontrol programs mainly aimed at controlling whiteflies and Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in greenhouses and open field. We evaluated the lethal and sublethal toxicity upon N. tenuis adults of label doses of three insecticides (pyriproxyfen, spirotetramat, cypermethrin) and seven fungicides (benomyl, chlorothalonil, copper oxychloride, cyazofamid, fluopicolide + propamocarb hydrochloride (FPH), penconazol, trifloxystrobin) commonly used in various crops. Two exposure routes were tested: (i) contact with dry residues of insecticides or fungicides on tomato sprouts and (ii) multiple exposure to these chemicals via topical sprays on adults which foraged on treated sprouts; and fed on treated eggs of Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) simultaneously. Mortality and reproductive capacity were investigated as indicators of lethal and sublethal effects on N. tenius. The tested insecticides and fungicides were all classified as harmless when predator was exposed only to the dry residues of each. However, the multiple exposure to either cypermethrin, benomyl, chlorothalonil, copper oxychloride or trifloxystrobin caused significant mortality of N. tenuis adults. Cypermethrin also significantly reduced its reproductive capacity. Interestingly, N. tenuis produced a higher number of progeny when exposed to fungicides penconazol and FPH in both exposure scenarios. Overall, findings suggest that the two insecticides, pyriproxyfen and spirotetramat but not cypermethrin, and all tested fungicides can be considered compatible with N. tenuis.

  3. Granulocyte macrophage colony-stimulating factor enhances the modulatory effect of cytokines on monocyte-derived multinucleated giant cell formation and fungicidal activity against Paracoccidioides brasiliensis

    Directory of Open Access Journals (Sweden)

    Magda Paula Pereira do Nascimento

    2011-09-01

    Full Text Available Multinucleated giant cells (MGC are cells present in characteristic granulomatous inflammation induced by intracellular infectious agents or foreign materials. The present study evaluated the modulatory effect of granulocyte macrophage colony-stimulating factor (GM-CSF in association with other cytokines such as interferon-gamma (IFN-γ, tumour necrosis factor-alpha, interleukin (IL-10 or transforming growth factor beta (TGF-β1 on the formation of MGC from human peripheral blood monocytes stimulated with Paracoccidioides brasiliensis antigen (PbAg. The generation of MGC was determined by fusion index (FI and the fungicidal activity of these cells was evaluated after 4 h of MGC co-cultured with viable yeast cells of P. brasiliensis strain 18 (Pb18. The results showed that monocytes incubated with PbAg and GM-CSF plus IFN-γ had a significantly higher FI than in all the other cultures, while the addition of IL-10 or TGF-β1 had a suppressive effect on MGC generation. Monocytes incubated with both pro and anti-inflammatory cytokines had a higher induction of foreign body-type MGC rather than Langhans-type MGC. MGC stimulated with PbAg and GM-CSF in association with the other cytokines had increased fungicidal activity and the presence of GM-CSF also partially inhibited the suppressive effects of IL-10 and TGF-β1. Together, these results suggest that GM-CSF is a positive modulator of PbAg-stimulated MGC generation and on the fungicidal activity against Pb18.

  4. Potential effects of environmental conditions on the efficiency of the antifungal tebuconazole controlling Fusarium verticillioides and Fusarium proliferatum growth rate and fumonisin biosynthesis.

    Science.gov (United States)

    Marín, Patricia; de Ory, Ana; Cruz, Alejandra; Magan, Naresh; González-Jaén, M Teresa

    2013-08-01

    Fusarium verticillioides and Fusarium proliferatum are important phytopathogens which contaminate cereals in the Mediterranean climatic region with fumonisins. In this study we examined the interaction between the fungicide efficacy of tebuconazole and water potential (Ψw) (-0.7-7.0MPa)×temperature (20-35°C) on growth and FUM1 gene expression by real time RT-PCR (an indicator of fumonisin biosynthesis) in strains of both Fusarium species. Concentrations of tebuconazole required to reduce growth by 50 and 90% (ED50 and ED90 values) were determined. Growth of strains of both species was largely reduced by tebuconazole, with similar efficacy profiles in the interacting water potential×temperature conditions. In contrast, FUM1 expression was not generally reduced by tebuconazole. Moreover, sub-lethal doses in combination with mild water stress and temperatures less than 35°C significantly induced FUM1 expression with slight differences in both species. These results suggest that the efficacy of antifungal compounds to reduce mycotoxin risk would be more effective if consideration is given to both growth rate and toxin biosynthesis in relation to interacting environmental conditions. This is the first study linking fungicide efficacy of tebuconazole with environmental factor effects on control of growth and FUM1 gene expression of F. verticillioides and F. proliferatum. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Vitamin and co-factor biosynthesis pathways in Plasmodium and other apicomplexan parasites

    Science.gov (United States)

    Müller, Sylke; Kappes, Barbara

    2007-01-01

    Vitamins are essential components of the human diet. By contrast, the malaria parasite Plasmodium falciparum and related apicomplexan parasites synthesise certain vitamins, de novo, either completely or in parts. The occurrence of the various biosynthesis pathways is specific to different apicomplexan parasites, emphasising their distinct requirements for nutrients and growth factors. The absence of vitamin biosynthesis from the human host implies that inhibition of the parasite pathways may be a way to interfere specifically with parasite development. However, the precise role of biosynthesis and potential uptake of vitamins for the overall regulation of vitamin homeostasis in the parasites needs to be established first. In this review Sylke Müller and Barbara Kappes focus mainly on the procurement of vitamin B1, B5 and B6 by Plasmodium and other apicomplexan parasites. PMID:17276140

  6. Suppression of the biosynthesis of proanthocyanidin in Arabidopsis by a chimeric PAP1 repressor.

    Science.gov (United States)

    Matsui, Kyoko; Tanaka, Hideo; Ohme-Takagi, Masaru

    2004-11-01

    Flavonoids are secondary metabolites that are specific to higher plants. PAP1, a member of the family of MYB domain transcription factors in Arabidopsis, is a positive regulator of the biosynthesis of anthocyanin. We show here that a chimeric PAP1 repressor, in which the EAR-motif repression domain from SUPERMAN was fused to PAP1, suppressed the expression of four flavonoid biosynthetic genes, namely CHS, DFR, LDOX, and BAN, in siliques, and inhibited the accumulation of proanthocyanidin, even in the presence of an endogenous positive regulator, such as TT2. This suppression resulted in the formation of light yellow seeds in 35S::PAP1SRDX transgenic plants. Our results indicate that PAP1 has the potential ability to regulate the biosynthesis not only of anthocyanin but also of proanthocyanidin. Our gene silencing system, using chimeric repressors, appears to be a useful tool for the manipulation of the biosynthesis of secondary metabolites in plants.

  7. Co-Compartmentation of Terpene Biosynthesis and Storage via Synthetic Droplet

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Cheng [Texas; amp,M Agrilife Synthetic and Systems Biology Innovation Hub, Texas A& amp,M University, College Station, Texas 77843, United States; Department; amp,M University, College Station, Texas 77843, United States; Institute; amp,M University, College Station, Texas 77843, United States; Kim, YongKyoung [Texas; amp,M Agrilife Synthetic and Systems Biology Innovation Hub, Texas A& amp,M University, College Station, Texas 77843, United States; Department; amp,M University, College Station, Texas 77843, United States; Institute; amp,M University, College Station, Texas 77843, United States; Zeng, Yining [Biosciences; Li, Man [Texas; amp,M Agrilife Synthetic and Systems Biology Innovation Hub, Texas A& amp,M University, College Station, Texas 77843, United States; Department; amp,M University, College Station, Texas 77843, United States; Institute; amp,M University, College Station, Texas 77843, United States; Wang, Xin [Texas; amp,M Agrilife Synthetic and Systems Biology Innovation Hub, Texas A& amp,M University, College Station, Texas 77843, United States; Department; amp,M University, College Station, Texas 77843, United States; Institute; amp,M University, College Station, Texas 77843, United States; Hu, Cheng [Texas; amp,M Agrilife Synthetic and Systems Biology Innovation Hub, Texas A& amp,M University, College Station, Texas 77843, United States; Department; amp,M University, College Station, Texas 77843, United States; Institute; amp,M University, College Station, Texas 77843, United States; Gorman, Connor [Texas; amp,M Agrilife Synthetic and Systems Biology Innovation Hub, Texas A& amp,M University, College Station, Texas 77843, United States; Department; amp,M University, College Station, Texas 77843, United States; Institute; amp,M University, College Station, Texas 77843, United States; Dai, Susie Y. [State; Ding, Shi-You [Department; Yuan, Joshua S. [Texas; amp,M Agrilife Synthetic and Systems Biology Innovation Hub, Texas A& amp,M University, College Station, Texas 77843, United States; Department; amp,M University, College Station, Texas 77843, United States; Institute; amp,M University, College Station, Texas 77843, United States

    2018-02-16

    Traditional bioproduct engineering focuses on pathway optimization, yet is often complicated by product inhibition, downstream consumption, and the toxicity of certain products. Here, we present the co-compartmentation of biosynthesis and storage via a synthetic droplet as an effective new strategy to improve the bioproduct yield, with squalene as a model compound. A hydrophobic protein was designed and introduced into the tobacco chloroplast to generate a synthetic droplet for terpene storage. Simultaneously, squalene biosynthesis enzymes were introduced to chloroplasts together with the droplet-forming protein to co-compartmentalize the biosynthesis and storage of squalene. The strategy has enabled a record yield of squalene at 2.6 mg/g fresh weight without compromising plant growth. Confocal fluorescent microscopy imaging, stimulated Raman scattering microscopy, and droplet composition analysis confirmed the formation of synthetic storage droplet in chloroplast. The co-compartmentation of synthetic storage droplet with a targeted metabolic pathway engineering represents a new strategy for enhancing bioproduct yield.

  8. TENACITY AND PERSISTENCE OF COPPER FUNGICIDES IN CITRUS SEEDLINGS UNDER SIMULATED RAINFALL

    Directory of Open Access Journals (Sweden)

    ANTONIO EDUARDO FONSECA

    2016-01-01

    Full Text Available The amount of fungicide that adheres to the leaf during spraying and the amount that remain on the leaf after weathering are the main factors that defines the amount of active residue on the leaf surface to effectively control plant pathogens. Thus, the objective of this work was to evaluate the tenacity and persistence of copper in citrus seedling leaves under simulated rainfall in Jaboticabal, State of São Paulo, Brazil. The evaluated variables were copper content, solution retention, surface tension and drop spectrum. A significant and inversely proportional linear relationship to drops <100 μm was found. The percentage of copper retained in leaves of citrus seedlings with copper fungicides of suspension concentrate (SC formulations after simulated rainfall was greater than 80%. Copper fungicides of SC formulations presented the lowest surface tension, allowing greater tenacity and persistence of copper on seedlings of citrus leaves after simulated rainfall and increased contact between the drops and leaf surface.

  9. In vitro Determination of Fungicide Inhibitory Concentration for Phakopsora pachyrhizi isolates

    Directory of Open Access Journals (Sweden)

    Bianca Moura

    2016-06-01

    Full Text Available ABSTRACT In vitro assays were preformed to obtain the IC50 of eight fungicides against Phakopsora pachyrhizi isolates from Passo Fundo, RS, Ponta Grossa, PR, and Primavera do Leste, MT. Different concentrations of the fungicides were added to Petri dishes containing soybean leaf extract agar medium. One milliliter of P. pachyrhizi uredospore suspension at the concentration of 3.0 x 104 uredospores/mL was added to each dish for subsequent viability quantification. Only pyraclostrobin and the mixture trifloxystrobin + prothioconazole showed IC50 values inferior to 1.0 mg/L for all tested isolates, demonstrating high fungitoxicity. There was not loss of sensitivity to any of the tested fungicides.

  10. Community composition of target vs. non-target fungi in fungicide treated wheat

    DEFF Research Database (Denmark)

    Knorr, Kamilla; Jørgensen, Lise Nistrup; Justesen, Annemarie Fejer

    2012-01-01

    of three fungicides. The fungal composition in bulked leaf samples and individual leaves was studied by deep amplicon 454 pyrosequencing targeting the internal transcribed spacer-1 (ITS1) region of the ribosomal DNA. Amount of yellow rust in individual samples was quantified by qPCR. Pyrosequencing......Fungicide treatments are common control strategies used to manage fungal pathogens in agricultural fields, however, effects of treatments on the composition of total fungal communities, including non-target fungi, in the phyllosphere is not well known. Yellow rust (Puccinia striiformis) is a common...... in an amount of yellow rust below detection level. Fungal diversity was stable across treatments whereas the relative abundance of individual OTUs was affected by fungicide treatment....

  11. Environmental fate of fungicides and other current-use pesticides in a central California estuary

    Science.gov (United States)

    Smalling, Kelly L.; Kuivila, Kathryn; Orlando, James L.; Phillips, Bryn M.; Anderson, Brian S.; Siegler, Katie; Hunt, John W.; Hamilton, Mary

    2013-01-01

    The current study documents the fate of current-use pesticides in an agriculturally-dominated central California coastal estuary by focusing on the occurrence in water, sediment and tissue of resident aquatic organisms. Three fungicides (azoxystrobin, boscalid, and pyraclostrobin), one herbicide (propyzamide) and two organophosphate insecticides (chlorpyrifos and diazinon) were detected frequently. Dissolved pesticide concentrations in the estuary corresponded to the timing of application while bed sediment pesticide concentrations correlated with the distance from potential sources. Fungicides and insecticides were detected frequently in fish and invertebrates collected near the mouth of the estuary and the contaminant profiles differed from the sediment and water collected. This is the first study to document the occurrence of many current-use pesticides, including fungicides, in tissue. Limited information is available on the uptake, accumulation and effects of current-use pesticides on non-target organisms. Additional data are needed to understand the impacts of pesticides, especially in small agriculturally-dominated estuaries.

  12. Effect of nozzle type on the fungicide efficacy for fusarium head blight suppression on wheat

    Directory of Open Access Journals (Sweden)

    Šterbik Ildiko R.

    2017-01-01

    Full Text Available Effect of fungicide treatments on Fusarium head blight (FHB and grain yield of wheat depending on application technique i.e. use of different nozzle types, was evaluated in the study. Nozzles types TJ 11004, Albuz ATR 8004 and Arag TFA 11004 were used for application of systemic fungicide Duett Ultra (0.5 l/ha. FHB intensity (% was determined on the basis of a visual assessment of the number of infected heads and the perecentage of the disease symptoms on the individual head. Differences in grain yield between the treated variants, as well as between the treated and untreated variants, were determined after hand threshing. The lowest percentage of FHB development in wheat and the highest yield were recorded in variants where fungicides were applied by nozzle type ATR 8004. Application technique directly affects the reduction of fusarium head blight in wheat and indirectly it also reduces yield loss.

  13. Regulatory variability of camalexin biosynthesis.

    Science.gov (United States)

    Schuhegger, Regina; Rauhut, Thomas; Glawischnig, Erich

    2007-05-01

    The anthranilate synthase ASA1, CYP79B2 and CYP71B15 (PAD3) are biosynthetic genes of the Arabidopsis phytoalexin camalexin, which are induced after pathogen infection and abiotic treatments like silver nitrate spraying. The natural variation of camalexin biosynthesis in response to Pseudomonas syringae infection was determined in several ecotypes, and differential CYP71B15 regulation as a potential basis for this variation was investigated. The expression of camalexin biosynthetic genes was restricted to the tissue undergoing cell death. After droplet infection with Alternaria alternata, a potent camalexin inducer in the Col-0 ecotype, camalexin formation and the induction of ASA1, CYP79B2 and CYP71B15 were strictly co-localized with the infection site.

  14. Effect of Maize Hybrid and Foliar Fungicides on Yield Under Low Foliar Disease Severity Conditions.

    Science.gov (United States)

    Mallowa, Sally O; Esker, Paul D; Paul, Pierce A; Bradley, Carl A; Chapara, Venkata R; Conley, Shawn P; Robertson, Alison E

    2015-08-01

    Foliar fungicide use in the U.S. Corn Belt increased in the last decade; however, questions persist pertaining to its value and sustainability. Multistate field trials were established from 2010 to 2012 in Illinois, Iowa, Ohio, and Wisconsin to examine how hybrid and foliar fungicide influenced disease intensity and yield. The experimental design was in a split-split plot with main plots consisting of hybrids varying in resistance to gray leaf spot (caused by Cercospora zeae-maydis) and northern corn leaf blight (caused by Setosphaera turcica), subplots corresponding to four application timings of the fungicide pyraclostrobin, and sub-subplots represented by inoculations with either C. zeae-maydis, S. turcica, or both at two vegetative growth stages. Fungicide application (VT/R1) significantly reduced total disease severity relative to the control in five of eight site-years (P<0.05). Disease was reduced by approximately 30% at Wisconsin in 2011, 20% at Illinois in 2010, 29% at Iowa in 2010, and 32 and 30% at Ohio in 2010 and 2012, respectively. These disease severities ranged from 0.2 to 0.3% in Wisconsin in 2011 to 16.7 to 22.1% in Illinois in 2010. The untreated control had significantly lower yield (P<0.05) than the fungicide-treated in three site-years. Fungicide application increased the yield by approximately 6% at Ohio in 2010, 5% at Wisconsin in 2010 and 6% in 2011. Yield differences ranged from 8,403 to 8,890 kg/ha in Wisconsin 2011 to 11,362 to 11,919 kg/ha in Wisconsin 2010. Results suggest susceptibility to disease and prevailing environment are important drivers of observed differences. Yield increases as a result of the physiological benefits of plant health benefits under low disease were not consistent.

  15. Using epidemiological principles to explain fungicide resistance management tactics: why do mixtures outperform alternations?

    Science.gov (United States)

    Elderfield, James A; Lopez Ruiz, Fran; van den Bosch, Frank; Cunniffe, Nik J

    2018-01-29

    Whether fungicide resistance management is optimised by spraying chemicals with different modes of action as a mixture (i.e. simultaneously) or in alternation (i.e. sequentially) has been studied by experimenters and modellers for decades. However results have been inconclusive. We use previously-parameterised and validated mathematical models of wheat septoria leaf blotch and grapevine powdery mildew to test which tactic provides better resistance management, using the total yield before resistance causes disease control to become economically-ineffective ("lifetime yield") to measure effectiveness. We focus on tactics involving the combination of a low-risk and a high-risk fungicide, and the case in which resistance to the high-risk chemical is complete (i.e. in which there is no partial resistance). Lifetime yield is then optimised by spraying as much low-risk fungicide as is permitted, combined with slightly more high-risk fungicide than needed for acceptable initial disease control, applying these fungicides as a mixture. That mixture rather than alternation gives better performance is invariant to model parameterisation and structure, as well as the pathosystem in question. However if comparison focuses on other metrics, e.g. lifetime yield at full label dose, either mixture or alternation can be optimal. Our work shows how epidemiological principles can explain the evolution of fungicide resistance, and also highlights a theoretical framework to address the question of whether mixture or alternation provides better resistance management. It also demonstrates that precisely how spray tactics are compared must be given careful consideration.

  16. Combinations of fungicide and cultural practices influence the incidence and impact of fusiform rust in slash pine plantations

    Science.gov (United States)

    James D. Haywood; Allan E. Tiarks

    1994-01-01

    Slash pine was grown in central Louisiana under four levels of culture with or without repeated sprayings of the systematic fungicide triadimefon for protection against fusiform rust. The eight treatment combinations were: (1)no fungicide, weed control, or fertilizer; (2)weeded; (3)weeded, applied inorganic fertilizer, and bedded before planting; (4)weeded, bedded,...

  17. Rainfall thresholds as support for timing fungicide applications in the control of potato late blight in Ecuador and Peru

    DEFF Research Database (Denmark)

    Kromann, Peter; Taipe, Arturo; Perez, Willmer G.

    2009-01-01

    Accumulated rainfall thresholds were studied in seven field experiments conducted in Ecuador and Peru for their value in timing applications of fungicide to control potato late blight, caused by Phytophthora infestans. Fungicide regimes based on accumulated rainfall thresholds ranging from 10 to 70...

  18. Effect of fungicides and biocontrol agents on inoculum production and persistence of Phytophthora ramorum on nursery hosts

    Science.gov (United States)

    Steve Tjosvold; David Chambers; Gary Chastagner; Marianne. Elliott

    2013-01-01

    Once Phytophthora ramorum is introduced into a nursery on a host, its local spread and establishment is primarily dependent on sporangia and zoospore production. Nursery operators commonly use fungicides to prevent the establishment of Phytophthora –caused diseases, although current research only supports the use of fungicides...

  19. Baseline sensitivity to fluopyram and fungicide resistance phenotypes of botrytis cinerea populations from table grapes in california

    Science.gov (United States)

    Gray mold caused by Botrytis cinerea is a major postharvest disease of table grapes grown in the Central Valley of California. Understanding fungicide-resistant phenotypes of B. cinerea is important to the development of pre-harvest fungicide programs for control of postharvest gray mold. Baseline s...

  20. Fungicide sensitivity of Tapesia yallundae populations collected from 15 wheat fields in the Western Cape of South Africa

    NARCIS (Netherlands)

    Ntushelo, K.; Crous, P.W.

    2004-01-01

    In the Western Cape province of South Africa, eyespot disease (Tapesia yallundae) of wheat is primarily controlled by fungicide applications. Previous studies have shown, however, that isolates of T. yallundae vary in their response to fungicides. In the present study, 20 isolates from each of 15

  1. Effects of the hydrogen potential and fungicide treatment on Pitaya seed germination

    OpenAIRE

    Ortiz, Thiago Alberto; Moritz, Aline; Oliveira, Mariana Alves de; Takahashi, Lúcia Sadayo Assari

    2015-01-01

    The objective of the present study was to evaluate pitaya seed germination under different hydrogen potentials, with or without fungicide treatment. A completely randomized design was employed under a 3 x 13 x 2 factorial scheme, corresponding to three pitaya species (white pitaya, pitaya hybrid I, pitaya hybrid II), thirteen hydrogen potentials (3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, and 9.0) and two fungicide conditions (presence and absence), with four replications. Th...

  2. The effect of foliar fungicides on the mycoflora of seeds of Triticum aestivum

    Directory of Open Access Journals (Sweden)

    Janusz Błaszkowski

    2014-08-01

    Full Text Available The effect of three foliar fungicides. i.e., Bayloton 25 WP, Dithane M-45, and Funaben K. on the mycoflora associated with the seeds of spring Triticum aestivum cv. Kolibri cultivated in the field was investigated. The fungicide which highly reduced the number of both fungal colonies and species was Funaben K. Of the fungi most frequently occurring. Only Funaben K applied on the seeds reduced the proportion of seeds with Alternaria alternata, Cladosporium spp.. and Septoria nodorum. In contrast. seeds from plants traeted with Funaben K harboured significantly more colonies of non-sporulating fungi.

  3. Differences in sensitivity between earthworms and enchytraeids exposed to two commercial fungicides.

    Science.gov (United States)

    Bart, Sylvain; Laurent, Céline; Péry, Alexandre R R; Mougin, Christian; Pelosi, Céline

    2017-06-01

    The use of pesticides in crop fields may have negative effects on soil Oligochaeta Annelida, i.e., earthworms and enchytraeids, and thus affect soil quality. The aim of this study was to assess the effects of two commercial fungicide formulations on the earthworm Aporrectodea caliginosa and the enchytraeid Enchytraeus albidus in a natural soil. The fungicides were Cuprafor micro® (copper oxychloride), commonly used in organic farming, and Swing Gold® (epoxiconazole and dimoxystrobin), a synthetic fungicide widely used in conventional farming to protect cereal crops. Laboratory experiments were used to assess the survival, biomass loss and avoidance behaviour. No lethal effect was observed following exposure to the copper fungicide for 14 days, even at 5000mgkg -1 of copper, i.e. 650 times the recommended dose (RD). However, a significant decrease in biomass was observed from 50mgkg -1 of copper (6.5 times the RD) for A. caliginosa and at 5000mgkg -1 of copper (650 times the RD) for E. albidus. These sublethal effects suggest that a longer period of exposure would probably have led to lethal effects. The EC50 avoidance for the copper fungicide was estimated to be 51.2mgkg -1 of copper (6.7 times the RD) for A. caliginosa, and 393mgkg -1 of copper (51 times the RD) for E. albidus. For the Swing Gold® fungicide, the estimated LC50 was 7.0 10 -3 mLkg -1 (6.3 times the RD) for A. caliginosa and 12.7 10 -3 mLkg -1 (11.0 times the RD) for E. albidus. No effect on biomass or avoidance was observed at sublethal concentrations of this synthetic fungicide. It was concluded that enchytraeids were less sensitive than earthworms to the two commercial fungicides in terms of mortality, biomass loss and avoidance behaviour. Therefore we discuss the different strategies possibly used by the two Oligochaeta species to cope with the presence of the pesticides were discussed, along with the potential consequences on the soil functions. Copyright © 2017 Elsevier Inc. All rights

  4. Synergism between demethylation inhibitor fungicides or gibberellin inhibitor plant growth regulators and bifenthrin in a pyrethroid-resistant population of Listronotus maculicollis (Coleoptera: Curculionidae).

    Science.gov (United States)

    Ramoutar, D; Cowles, R S; Requintina, E; Alm, S R

    2010-10-01

    In 2007-2008, the "annual bluegrass weevil," Listronotus maculicollis Kirby (Coleoptera: Curculionidae), a serious pest of Poa annua L. (Poales: Poaceae) on U.S. golf courses, was shown to be resistant to two pyrethroids, bifenthrin and lambda-cyhalothrin. In 2008, we showed that bifenthrin resistance was principally mediated by oxidase detoxification (cytochrome P450 [P450]). P450s can be inhibited by demethylation inhibitor fungicides and gibberellin inhibitor plant growth regulators, both of which are commonly used on golf courses. We tested these compounds for synergistic activity with bifenthin against a pyrethroid-resistant population of L. maculicollis. The LD50 value for bifenthrin was significantly reduced from 87 ng per insect (without synergists) to 9.6-40 ng per insect after exposure to the fungicides fenarimol, fenpropimorph, prochloraz, propiconazole, and pyrifenox and the plant growth regulators flurprimidol, paclobutrazol, and trinexapac-ethyl. Simulated field exposure with formulated products registered for use on turf revealed enhanced mortality when adult weevils were exposed to bifenthrin (25% mortality, presented alone) combined with field dosages of propiconizole, fenarimol, flurprimidol, or trinexapac-ethyl (range, 49-70% mortality).

  5. Cholesterol in mouse retina originates primarily from in situ de novo biosynthesis.

    Science.gov (United States)

    Lin, Joseph B; Mast, Natalia; Bederman, Ilya R; Li, Yong; Brunengraber, Henri; Björkhem, Ingemar; Pikuleva, Irina A

    2016-02-01

    The retina, a thin tissue in the back of the eye, has two apparent sources of cholesterol: in situ biosynthesis and cholesterol available from the systemic circulation. The quantitative contributions of these two cholesterol sources to the retinal cholesterol pool are unknown and have been determined in the present work. A new methodology was used. Mice were given separately deuterium-labeled drinking water and chow containing 0.3% deuterium-labeled cholesterol. In the retina, the rate of total cholesterol input was 21 μg of cholesterol/g retina • day, of which 15 μg of cholesterol/g retina • day was provided by local biosynthesis and 6 μg of cholesterol/g retina • day was uptaken from the systemic circulation. Thus, local cholesterol biosynthesis accounts for the majority (72%) of retinal cholesterol input. We also quantified cholesterol input to mouse brain, the organ sharing important similarities with the retina. The rate of total cerebral cholesterol input was 121 μg of cholesterol/g brain • day with local biosynthesis providing 97% of total cholesterol input. Our work addresses a long-standing question in eye research and adds new knowledge to the potential use of statins (drugs that inhibit cholesterol biosynthesis) as therapeutics for age-related macular degeneration, a common blinding disease. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.

  6. The RNA Chaperone Hfq Regulates Antibiotic Biosynthesis in the Rhizobacterium Pseudomonas aeruginosa M18

    Science.gov (United States)

    Wang, Guohao; Li, Sainan; Huang, Jiaofang; Wei, Xue; Li, Yaqian

    2012-01-01

    The rhizosphere microbe Pseudomonas aeruginosa M18 shows strong antifungal activities, mainly due to the biosynthesis of antibiotics like pyoluteorin (Plt) and phenazine-1-carboxylic acid (PCA). The ubiquitous RNA chaperone Hfq regulates bacterial virulence and stress tolerance through global posttranscriptional regulation. Here, we explored the molecular mechanism by which Hfq controls antibiotic biosynthesis in P. aeruginosa M18. The robust downregulation of Plt biosynthesis by Hfq was mediated exclusively by the posttranscriptional downregulation of the plt transcriptional activator PltR. Hfq posttranscriptionally repressed phzM expression and consequently reduced the conversion of PCA to pyocyanin. However, Hfq positively controlled the phz2 operon and PCA biosynthesis through both QscR-mediated transcriptional regulation at the promoter and an unknown regulation at the operator. Also, Hfq was shown to directly bind at the mRNA 5′ untranslated leaders of pltR, qscR, and phzM. These three negatively regulated target genes of Hfq shared a similar secondary structure with a short single-stranded AU-rich spacer (a potential Hfq-binding motif) linking two stem-loops. Taken together, these results indicate that Hfq, potentially in collaboration with unknown small noncoding RNAs (sRNAs), tightly controls antibiotic biosynthesis through both direct posttranscriptional inhibition and indirect transcriptional regulation. PMID:22427627

  7. Intra-annual trends of fungicide residues in waters from vineyard areas in La Rioja region of northern Spain.

    Science.gov (United States)

    Herrero-Hernández, Eliseo; Pose-Juan, Eva; Sánchez-Martín, María J; Andrades, M Soledad; Rodríguez-Cruz, M Sonia

    2016-11-01

    The temporal trends of fungicides in surface and ground water in 90 samples, including both surface waters (12) and ground waters (78) from an extensive vineyard area located in La Rioja (Spain), were examined between September 2010 and September 2011. Fungicides are used in increasing amounts on vines in many countries, and they may reach the water resources. However, few data have been published on fungicides in waters, with herbicides being the most frequently monitored compounds. The presence, distribution and year-long evolution of 17 fungicides widely used in the region and a degradation product were evaluated in waters during four sampling campaigns. All the fungicides included in the study were detected at one or more of the points sampled during the four campaigns. Metalaxyl, its metabolite CGA-92370, penconazole and tebuconazole were the fungicides detected in the greatest number of samples, although myclobutanil, CGA-92370 and triadimenol were detected at the highest concentrations. The highest levels of individual fungicides were found in Rioja Alavesa, with concentrations of up to 25.52 μg L -1 , and more than 40 % of the samples recorded a total concentration of >0.5 μg L -1 . More than six fungicides were positively identified in a third of the ground and surface waters in all the sampling campaigns. There were no significant differences between the results obtained in the four sampling campaigns and corroborated a pattern of diffuse contamination from the use of fungicides. The results confirm that natural waters in the study area are extremely vulnerable to contamination by fungicides and highlight the need to implement strategies to prevent and control water contamination by these compounds.

  8. Fungicidal activities and mechanisms of action of Pseudomonas syringae pv. syringae lipodepsipeptide syringopeptins 22A and 25A

    Directory of Open Access Journals (Sweden)

    Mekki F. Bensaci

    2011-10-01

    Full Text Available The plant-associated bacterium Pseudomonas syringae pv. syringae simultaneously produces two classes of metabolites: the small cyclic lipodepsinonapeptides such as the syringomycins and the larger cyclic lipodepsipeptide syringopeptins SP22 or SP25. The syringomycins inhibit a broad spectrum of fungi (but particularly yeasts by lipid-dependent membrane interaction. The syringopeptins are phytotoxic and inhibitory to Gram positive bacteria. In this study, the fungicidal activities of two major syringopeptins, SP22A and SP25A, and their mechanisms of action were investigated and compared to those of syringomycin E. SP22A and SP25A were observed to inhibit the fungal yeasts Saccharomyces cerevisiae and Candida albicans although less effectively than syringomycin E. S. cerevisiae mutants defective in ergosterol and sphingolipid biosyntheses were less susceptible to SP22A and SP25A but the relative inhibitory capabilities of SRE vs. SP22A and SP25A were maintained. Similar differences were observed for capabilities to cause cellular K+ and Ca2+ fluxes in S. cerevisiae. Interestingly, in phospholipid bilayers the syringopeptins are found to induce larger macroscopic ionic conductances than syringomycin E but form single channels with similar properties. These findings suggest that the syringopeptins target the yeast plasma membrane, and, like syringomycin E, employ a lipid-dependent channel forming mechanism of action. The differing degrees of growth inhibition by these lipodepsipeptides may be explained by differences in their hydrophobicity. The more hydrophobic SP22A and SP25A might interact more strongly with the yeast cell wall that would create a selective barrier for their incorporation into the plasma membrane.

  9. Monoterpene biosynthesis potential of plant subcellular compartments

    NARCIS (Netherlands)

    Dong, L.; Jongedijk, E.J.; Bouwmeester, H.J.; Krol, van der A.R.

    2016-01-01

    Subcellular monoterpene biosynthesis capacity based on local geranyl diphosphate (GDP) availability or locally boosted GDP production was determined for plastids, cytosol and mitochondria. A geraniol synthase (GES) was targeted to plastids, cytosol, or mitochondria. Transient expression in Nicotiana

  10. Antibacterial Targets in Fatty Acid Biosynthesis

    Science.gov (United States)

    Wright, H. Tonie; Reynolds, Kevin A.

    2008-01-01

    Summary The fatty acid biosynthesis pathway is an attractive but still largely unexploited target for development of new anti-bacterial agents. The extended use of the anti-tuberculosis drug isoniazid and the antiseptic triclosan, which are inhibitors of fatty acid biosynthesis, validates this pathway as a target for anti-bacterial development. Differences in subcellular organization of the bacterial and eukaryotic multi-enzyme fatty acid synthase systems offer the prospect of inhibitors with host vs. target specificity. Platensimycin, platencin, and phomallenic acids, newly discovered natural product inhibitors of the condensation steps in fatty acid biosynthesis, represent new classes of compounds with antibiotic potential. An almost complete catalogue of crystal structures for the enzymes of the type II fatty acid biosynthesis pathway can now be exploited in the rational design of new inhibitors, as well as the recently published crystal structures of type I FAS complexes. PMID:17707686

  11. Lincomycin, cultivation of producing strains and biosynthesis

    Czech Academy of Sciences Publication Activity Database

    Spížek, Jaroslav; Řezanka, Tomáš

    2004-01-01

    Roč. 63, - (2004), s. 510-519 ISSN 0175-7598 Institutional research plan: CEZ:AV0Z5020903 Keywords : lincomycin * cultivation * biosynthesis Subject RIV: EE - Microbiology, Virology Impact factor: 2.358, year: 2004

  12. Control of tylosin biosynthesis in Streptomyces fradiae.

    Science.gov (United States)

    Cundliffe, Eric

    2008-09-01

    Tylosin biosynthesis is controlled in cascade fashion by multiple transcriptional regulators, acting positively or negatively, in conjunction with a signalling ligand that acts as a classical inducer. The roles of regulatory gene products have been characterized by a combination of gene expression analysis and fermentation studies, using engineered strains of S. fradiae in which specific genes were inactivated or overexpressed. Among various novel features of the regulatory model, involvement of the signalling ligand is not essential for tylosin biosynthesis.

  13. Effects of current-use fungicides and their mixtures on the feeding and survival of the key shredder Gammarus fossarum.

    Science.gov (United States)

    Zubrod, J P; Baudy, P; Schulz, R; Bundschuh, M

    2014-05-01

    Fungicides are frequently applied in agriculture and are subsequently detected in surface waters in total concentrations of up to several tens of micrograms per liter. These concentrations imply potential effects on aquatic communities and fundamental ecosystem functions such as leaf litter breakdown. In this context, the present study investigates sublethal and lethal effects of organic (azoxystrobin, carbendazim, cyprodinil, quinoxyfen, and tebuconazole) and inorganic (three copper (Cu)-based substances and sulfur) current-use fungicides and their mixtures on the key leaf-shredding invertebrate Gammarus fossarum. The feeding activity of fungicide-exposed gammarids was quantified as sublethal endpoint using a static (organic fungicides; 7 d test duration) or a semi-static (inorganic fungicides; 6 d test duration with a water exchange after 3 d) approach (n=30). EC50-values of organic fungicides were generally observed at concentrations resulting in less than 20% mortality, with the exception of carbendazim. With regard to feeding, quinoxyfen was the most toxic organic fungicide, followed by cyprodinil, carbendazim, azoxystrobin, and tebuconazole. Although all tested organic fungicides have dissimilar (intended) modes of action, a mixture experiment revealed a synergistic effect on gammarids' feeding at high concentrations when using "independent action" as the reference model (∼35% deviation between predicted and observed effect). This may be explained by the presence of a synergizing azole fungicide (i.e. tebuconazole) in this mixture. Furthermore, lethal concentrations of all Cu-based fungicides assessed in this study were comparable amongst one another. However, they differed markedly in their effective concentrations when using feeding activity as the endpoint, with Cu-sulfate being most toxic, followed by Cu-hydroxide and Cu-octanoate. In contrast, sulfur neither affected survival nor the feeding activity of gammarids (up to ∼5 mg/L) but reduced Cu

  14. Asparagine Biosynthesis in Alfalfa (Medicago sativa L.) Root Nodules.

    Science.gov (United States)

    Snapp, S S; Vance, C P

    1986-10-01

    Rapid direct conversion of exogenously supplied [(14)C]aspartate to [(14)C] asparagine and to tricarboxylic cycle acids was observed in alfalfa (Medicago sativa L.) nodules. Aspartate aminotransferase activity readily converted carbon from exogenously applied [(14)C]aspartate into the tricarboxylic acid cycle with subsequent conversion to the organic acids malate, succinate, and fumarate. Aminooxyacetate, an inhibitor of aminotransferase activity, reduced the flow of carbon from [(14)C]aspartate into tricarboxylic cycle acids and decreased (14)CO(2) evolution by 99%. Concurrently, maximum conversion of aspartate to asparagine was observed in aminooxyacetate treated nodules (30 nanomoles asparagine per gram fresh weight per hour. Metabolism of [(14)C]aspartate and distribution of nodulefixed (14)CO(2) suggest that two pools of aspartate occur in alfalfa nodules: (a) one involved in asparagine biosynthesis, and (b) another supplying a malate/aspartate shuttle. Conversion of [(14)C]aspartate to [(14)C]asparagine was not inhibited by methionine sulfoximine, a glutamine synthetase inhibitor, or azaserine, a glutmate synthetase, inhibitor. The data did not indicate that asparagine biosynthesis in alfalfa nodules has an absolute requirement for glutamine. Radioactivity in the xylem sap, derived from nodule (14)CO(2) fixation, was markedly decreased by treating nodulated roots with aminooxyacetate, methionine sulfoximine, and azaserine. Inhibitors decreased the [(14)C]aspartate and [(14)]asparagine content of xylem sap by greater than 80% and reduced the total amino nitrogen content of xylem sap (including nonradiolabeled amino acids) by 50 to 80%. Asparagine biosynthesis in alfalfa nodules and transport in xylem sap are dependent upon continued aminotransferase activity and an uninterrupted assimilation of ammonia via the glutamine synthetase/glutamate synthase pathway. Continued assimilation of ammonia apparently appears crucial to continued root nodule CO(2) fixation in

  15. Biosynthesis of antibiotic chuangxinmycin from Actinoplanes tsinanensis

    Directory of Open Access Journals (Sweden)

    Yuanyuan Shi

    2018-03-01

    Full Text Available Chuangxinmycin is an antibiotic isolated from Actinoplanes tsinanensis CPCC 200056 in the 1970s with a novel indole-dihydrothiopyran heterocyclic skeleton. Chuangxinmycin showed in vitro antibacterial activity and in vivo efficacy in mouse infection models as well as preliminary clinical trials. But the biosynthetic pathway of chuangxinmycin has been obscure since its discovery. Herein, we report the identification of a stretch of DNA from the genome of A. tsinanensis CPCC 200056 that encodes genes for biosynthesis of chuangxinmycin by bioinformatics analysis. The designated cxn cluster was then confirmed to be responsible for chuangxinmycin biosynthesis by direct cloning and heterologous expressing in Streptomyces coelicolor M1146. The cytochrome P450 CxnD was verified to be involved in the dihydrothiopyran ring closure reaction by the identification of seco-chuangxinmycin in S. coelicolor M1146 harboring the cxn gene cluster with an inactivated cxnD. Based on these results, a plausible biosynthetic pathway for chuangxinmycin biosynthesis was proposed, by hijacking the primary sulfur transfer system for sulfur incorporation. The identification of the biosynthetic gene cluster of chuangxinmycin paves the way for elucidating the detail biochemical machinery for chuangxinmycin biosynthesis, and provides the basis for the generation of novel chuangxinmycin derivatives by means of combinatorial biosynthesis and synthetic biology. KEY WORDS: Chuangxinmycin, Actinoplanes tsinanensis, Biosynthesis gene cluster, Heterologous expression, Cytochrome P450, Seco-chuangxinmycin, C–S bond formation, Sulfur incorporation

  16. Proposal for a unified nomenclature for target-site mutations associated with resistance to fungicides.

    Science.gov (United States)

    Mair, Wesley; Lopez-Ruiz, Francisco; Stammler, Gerd; Clark, William; Burnett, Fiona; Hollomon, Derek; Ishii, Hideo; Thind, Tarlochan S; Brown, James Km; Fraaije, Bart; Cools, Hans; Shaw, Michael; Fillinger, Sabine; Walker, Anne-Sophie; Mellado, Emilia; Schnabel, Guido; Mehl, Andreas; Oliver, Richard P

    2016-08-01

    Evolved resistance to fungicides is a major problem limiting our ability to control agricultural, medical and veterinary pathogens and is frequently associated with substitutions in the amino acid sequence of the target protein. The convention for describing amino acid substitutions is to cite the wild-type amino acid, the codon number and the new amino acid, using the one-letter amino acid code. It has frequently been observed that orthologous amino acid mutations have been selected in different species by fungicides from the same mode of action class, but the amino acids have different numbers. These differences in numbering arise from the different lengths of the proteins in each species. The purpose of the present paper is to propose a system for unifying the labelling of amino acids in fungicide target proteins. To do this we have produced alignments between fungicide target proteins of relevant species fitted to a well-studied 'archetype' species. Orthologous amino acids in all species are then assigned numerical 'labels' based on the position of the amino acid in the archetype protein. © 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2016 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  17. Effects of Artea, a systemic fungicide, on the antioxidant system and ...

    African Journals Online (AJOL)

    The present work is aimed at the study of Artea (a systemic fungicide) effects on durum wheat (Triticum durum L. CV. Hard GTA). Seeds were grown in a medium containing 25, 50, 75 and 100 ppm of Artea under controlled conditions. Roots of eight day old were used to determine the enzymatic activities of catalase, ...

  18. Evaluation of certain fungicides for the control of tar spot disease of ...

    African Journals Online (AJOL)

    The present study evaluated the favourable conditions as well as the effectiveness of fungicides in controlling the disease. Ben/ate, Dithane M-45 and Polyram-Combi at the rates of 1.0, 1. 5 and l. 5 gil of water respectively either totally or almost completely controlled the disease when aerial parts of the vines were sprayed ...

  19. Effect of mulch and different fungicide spray regimes on yield of ...

    African Journals Online (AJOL)

    Treatment factors comprised two varieties (main plot factor), mulching/number of mulching (subplot factor) and three fungicide spray regimes (sub subplot factor). Results showed that the spray regimes: farmers' practice (FP), Integrated Pests Management (IPM) based on pests scouting, sprays based on manufacturers' ...

  20. Effect of foliar application of fungicides on incidence and severity of ...

    African Journals Online (AJOL)

    Three fungicides were evaluated for their efficacy in controlling leaf spot disease in Roselle induced by Coniella musaiaensis in a randomized compete block design experiment in 2003 at Abeokuta, (7015'N, 3025'E) a transition zone in South Western Nigeria. The experiment was replicated three times and repeated in ...

  1. Reaction kinetics and mechanisms of organosilicon fungicide flusilazole with sulfate and hydroxyl radicals.

    Science.gov (United States)

    Mercado, D Fabio; Bracco, Larisa L B; Arques, Antonio; Gonzalez, Mónica C; Caregnato, Paula

    2018-01-01

    Flusilazole is an organosilane fungicide used for treatments in agriculture and horticulture for control of diseases. The reaction kinetics and mechanism of flusilazole with sulfate and hydroxyl radicals were studied. The rate constant of the radicals with the fungicide were determined by laser flash photolysis of peroxodisulfate and hydrogen peroxide. The results were 2.0 × 10 9 s -1 M -1 for the reaction of the fungicide with HO and 4.6 × 10 8  s -1  M -1 for the same reaction with SO 4 - radicals. The absorption spectra of organic intermediates detected by laser flash photolysis of S 2 O 8 2- with flusilazole, were identified as α-aminoalkyl and siloxyl radicals and agree very well with those estimated employing the time-dependent density functional theory with explicit account for bulk solvent effects. In the continuous photolysis experiments, performed by photo-Fenton reaction of the fungicide, the main degradation products were: (bis(4-fluorophenyl)-hydroxy-methylsilane) and the non-toxic silicic acid, diethyl bis(trimethylsilyl) ester, in ten and twenty minutes of reaction, respectively. Copyright © 2017. Published by Elsevier Ltd.

  2. Analysis of Fungicide Sensitivity and Genetic Diversity among Colletotrichum Species in Sweet Persimmon.

    Science.gov (United States)

    Gang, Geun-Hye; Cho, Hyun Ji; Kim, Hye Sun; Kwack, Yong-Bum; Kwak, Youn-Sig

    2015-06-01

    Anthracnose, caused by Colletotrichum gloeosporioides (C. gloeosporioides; Teleomorph: Glomerella cingulata), is the most destructive disease that affects sweet persimmon production worldwide. However, the biology, ecology, and genetic variations of C. gloeosporioides remain largely unknown. Therefore, in this study, the development of fungicide resistance and genetic diversity among an anthracnose pathogen population with different geographical origins and the exposure of this population to different cultivation strategies were investigated. A total of 150 pathogen isolates were tested in fungicide sensitivity assays. Five of the tested fungicides suppressed mycelial pathogen growth effectively. However, there were significant differences in the sensitivities exhibited by the pathogen isolates examined. Interestingly, the isolates obtained from practical management orchards versus organic cultivation orchards showed no differences in sensitivity to the same fungicide. PCR-restriction fragment length polymorphism (RFLP) analyses were performed to detect internal transcribed spacer regions and the β-tubulin and glutamine synthetase genes of the pathogens examined. Both the glutamine synthetase and β-tubulin genes contained a complex set of polymorphisms. Based on these results, the pathogens isolated from organic cultivation orchards were found to have more diversity than the isolates obtained from the practical management orchards.

  3. Analysis of Fungicide Sensitivity and Genetic Diversity among Colletotrichum Species in Sweet Persimmon

    Directory of Open Access Journals (Sweden)

    Geun-Hye Gang

    2015-06-01

    Full Text Available Anthracnose, caused by Colletotrichum gloeosporioides (C. gloeosporioides; Teleomorph: Glomerella cingulata, is the most destructive disease that affects sweet persimmon production worldwide. However, the biology, ecology, and genetic variations of C. gloeosporioides remain largely unknown. Therefore, in this study, the development of fungicide resistance and genetic diversity among an anthracnose pathogen population with different geographical origins and the exposure of this population to different cultivation strategies were investigated. A total of 150 pathogen isolates were tested in fungicide sensitivity assays. Five of the tested fungicides suppressed mycelial pathogen growth effectively. However, there were significant differences in the sensitivities exhibited by the pathogen isolates examined. Interestingly, the isolates obtained from practical management orchards versus organic cultivation orchards showed no differences in sensitivity to the same fungicide. PCR-restriction fragment length polymorphism (RFLP analyses were performed to detect internal transcribed spacer regions and the β-tubulin and glutamine synthetase genes of the pathogens examined. Both the glutamine synthetase and β-tubulin genes contained a complex set of polymorphisms. Based on these results, the pathogens isolated from organic cultivation orchards were found to have more diversity than the isolates obtained from the practical management orchards.

  4. Evaluation of fungicides for the control of false smut of rice caused ...

    African Journals Online (AJOL)

    Benomyl, Copper Oxychloride, Iprodione, Thiabendazole (TBZ) and Mancozeb were evaluated both in the laboratory and field study in 1994, for the control of false smut of rice caused by Ustilaginoidea virens (Cooke) Tak. in upland rice in Edo State, Nigeria. In the laboratory the fungicides were evaluated at three ...

  5. Effects of artea, a systemic fungicide, on the antioxidant system and ...

    African Journals Online (AJOL)

    The present work aimed at the study of the effects of Artea, a systemic azole fungicide, on durum Wheat (Triticum durum L. cv. GTA dur). Seeds were grown in a medium containing respectively 25, 50, 75 and 100 ppm of Artea under controlled conditions. Roots of eight-day-old plants were used to determine catalase, ...

  6. The fungicidal properties of the carbon materials obtained from chitin and chitosan promoted by copper salts

    Energy Technology Data Exchange (ETDEWEB)

    Ilnicka, Anna, E-mail: annakucinska@o2.pl; Walczyk, Mariusz; Lukaszewicz, Jerzy P.

    2015-07-01

    Renewable raw materials chitin and chitosan (N-deacetylated derivative of chitin) were subjected to action of different copper modifiers that were carbonized in the atmosphere of the N{sub 2} inert gas. As a result of the novel manufacturing procedure, a series of carbon materials was obtained with developed surface area and containing copper derivatives of differentiated form, size, and dispersion. The copper modifier and manufacturing procedure (concentration, carbonization temperature) influence the physical–chemical and fungicide properties of the carbons. The received carbons were chemically characterized using several methods like low-temperature adsorption of nitrogen, X-ray diffraction analysis, scanning electron microscopy, cyclic voltammetry, elemental analysis, and bioassay. Besides chemical testing, some biological tests were performed and let to select carbons with the highest fungicidal activity. Such carbons were characteristic of the specific form of copper derivatives occurring in them, i.e., nanocrystallites of Cu{sup 0} and/or Cu{sub 2}O of high dispersion on the surface of carbon. The carbons may find an application as effective contact fungistatic agents in cosmetology, medicine, food industry, etc. - Highlights: • The novel manufacturing procedure yields new functional carbon materials. • Two biopolymers chitin and chitosan can undergo copper(II) ion modification. • The Cu-modified carbon materials exhibit high fungicidal activity. • The fungicidal activity results from the presence of Cu{sup 0} and Cu{sub 2}O nano-crystallites.

  7. Management of resistance to the fungicide fenpropimorph in Erysiphe graminis f.sp tritici

    NARCIS (Netherlands)

    Engels, A.J.G.

    1998-01-01

    In the last three decades, plant disease control has become heavily dependent on fungicides. This practice increased yield significantly but had also negative side-effects on the environment. In many countries, integrated control programs have been initiated in order to reduce pesticide use

  8. Control of clavicipitaceous anamorphic endophytes with fungicides, aerated steam and supercritical fluid CO2-seed extraction

    Science.gov (United States)

    A. Dan Wilson; Donald G. Lester; Brian K. Luckenbill

    2008-01-01

    The effects of soil drenches with systemic fungicides on viability of clavicipitaceous anamorphic endophytes, non-choke inducing endosymbiotic fungi of the genus Neotyphodium that systemically infect grasses, were tested in endophyte-infected seedlings of Hordeum brevisubulatum subsp. violaceum, Lolium perenne...

  9. Fungicides efficiency on wheat diseases control in response to the application with different spray nozzles

    Directory of Open Access Journals (Sweden)

    Felipe Rafael Garcés Fiallos

    2011-12-01

    Full Text Available This study aimed to evaluate the efficiency of fungicides to leaf control diseases of wheat, when applied to different models of spray nozzles. The experiment was conducted in a randomized block design with four replicates of factorial (4 x 3+1. Data were subjected to analysis of variance and means compared by Tukey test at 5% probability. The fungicides used were: Opera® (pyraclostrobin+epoxiconazole 0.75 L.ha-1 , Opera® 0.75 L.ha-1 +Folicur® (tebuconazole 0.3 L.ha-1 , Priori Xtra® (azoxystrobin+cyproconazole 0.3 L.ha-1 , Priori Xtra® 0.3 L.ha-1 +Tilt® (propiconazole 0.3 L.ha-1 . These fungicides were applied with three models of spray nozzles jet planes: XR 11 001 (fine drop, AIRMIX 11,001 (average drop and AVI 11,001 (coarse drop. We evaluated the incidence and severity (damage per plant leaf of yellow spot (Drechslera tritici-repentis, spot blotch (Bipolaris sorokiniana, leaf rust (Puccinia triticina and grain yield (kg.ha-1 culture. The results show that the application of fungicides for control of leaf diseases in wheat resulted in increases in grain yield, and yield higher values were observed with the application of Opera®, using the XR 11001.

  10. Phenotypical and Molecular Characterisation of Fusarium circinatum: Correlation with Virulence and Fungicide Sensitivity

    Directory of Open Access Journals (Sweden)

    Martin Mullett

    2017-11-01

    Full Text Available Fusarium circinatum, causing pine pitch canker, is one of the most damaging pathogens of Pinus species. This study investigated the use of phenotypical and molecular characteristics to delineate groups in a worldwide collection of isolates. The groups correlated with virulence and fungicide sensitivity, which were tested in a subset of isolates. Virulence tests of twenty isolates on P. radiata, P. sylvestris and P. pinaster demonstrated differences in host susceptibility, with P. radiata most susceptible and P. sylvestris least susceptible. Sensitivity to the fungicides fludioxonil and pyraclostrobin varied considerably between isolates from highly effective (half-maximal effective concentration (EC50 < 0.1 ppm to ineffective (EC50 > 100 ppm. This study demonstrates the potential use of simply acquired phenotypical (cultural, morphological and molecular metrics to gain a preliminary estimate of virulence and sensitivity to certain fungicides. It also highlights the necessity of including a range of isolates in fungicide tests and host susceptibility assays, particularly of relevance to tree breeding programmes.

  11. Determination of fungicide resistance in Botrytis cinerea from strawberry in the Central Coast Region of California

    Science.gov (United States)

    A study was conducted in 2013 to investigate the occurrence of fungicide resistance in Botrytis cinerea populations in California’s northern strawberry growing region; specifically in Watsonville and Salinas. In mid-May, 59 samples consisting of a single diseased fruit or plant part with gray mold s...

  12. Sensitivity reduction in Blumeria graminis f. sp. hordei to triadimenol fungicide applied as barley seed treatment

    Directory of Open Access Journals (Sweden)

    Erlei Melo Reis

    2013-12-01

    Full Text Available Experiments were carried out in a growth chamber with controlled temperature and photoperiod to test two populations of Blumeria graminis f. sp. hordei from Guarapuava, Paraná State, and Passo Fundo, Rio Grande do Sul State, Brazil. Treatments consisted in application of the fungicide triadimenol (Baytan 150 SC® at three rates of its commercial formulation: 150, 250, 350 mL/100 Kg barley seeds. The experiments were conducted separately in a growth chamber for each population, adopting the same temperature and photoperiod. For inoculation, pots containing barley seedlings colonized by the fungus were placed among the plots. After emergence of the first symptoms, the disease severity was assessed at two-day intervals. The experiments were repeated twice for each fungus population. Data were expressed as area under the disease progress curve and as powdery mildew control by comparing the severity after the fungicide treatments to that of control. Data were subjected to analysis of variance and regression analysis; the area under the disease progress curve was also calculated. Comparing the data obtained in the present study with those reported in the literature and the control, the maximum value of 26.1% is considered insufficient to prevent the damages caused by the disease. The control response to the fungicide rate was significant. We can conclude that there was a reduction in the sensitivity of both B. graminis f.sp. hordei populations to the fungicide triadimenol, which explains the control failure observed in barley farms.

  13. Evaluating fungicide sensitivity of regional Blumeria graminis f.sp. tritici populations in the United States

    Science.gov (United States)

    Blumeria graminis f.sp. tritici (Bgt), cause of wheat powdery mildew, has a high likelihood of developing fungicide resistance because of the large quantity of spores produced along with the mixed mode of reproduction. Additionally, once reduced sensitivity appears in a population it can influence n...

  14. The effect of fungicide dose on the composition of laboratory populations of barley powdery mildew

    DEFF Research Database (Denmark)

    O'Hara, R.B.; Nielsen, B.J.; Østergård, Hanne

    2000-01-01

    The effect of the use of different doses of the fungicide fenpropimorph on populations of barley powdery mildew Blumeria (Erysiphe) graminis f. sp. hordei was investigated in a laboratory selection experiment. A sample from the Danish aerial population of powdery mildew was split into populations...

  15. Predictive value of cell assays for developmental toxicity and embryotoxicity of conazole fungicides

    DEFF Research Database (Denmark)

    Sørensen, Karin Dreisig; Taxvig, Camilla; Kjærstad, Mia Birkhøj

    2013-01-01

    in reasonably good agreement with available in vivo effects. Ketoconazole and epoxiconazole are the most potent embryotoxic compounds, whereas prochloraz belongs to the most potent developmental toxicants. In conclusion, a rough prediction of the ranking of these conazole fungicides for in vivo toxicity data...

  16. Effect of equation pro and kema zed fungicides on cellulase and ...

    African Journals Online (AJOL)

    Two fungicides (equation pro and kema zed) were added to the medium in five doses (50,100, 200, 300 and 400 ppm active ingredient) to investigate the chemical control of cellulase and pectinase enzymes produced by some plant pathogens of broad bean. Alternaria alternata, Alternaria citri, Alternaria and Cochliobolus ...

  17. EFFECT OF CONAZOLE FUNGICIDES ON REPRODUCTIVE DEVELOPMENT IN THE FEMALE RAT

    Science.gov (United States)

    Three triazole fungicides were evaluated for effects on female rat reproductive development. Rats were exposed via feed to propiconazole (P) (100, 500, or 2500 ppm), myclobutanil (M) (100, 500, or 2000 ppm), or triadimefon (T) (100, 500, or 1800 ppm) from gestation day 6 to postn...

  18. Synthesis and fungicidal properties of 2,4-diaza-1,3,5 ...

    African Journals Online (AJOL)

    The preparation of 2,4-diaza-1,3,5-pentanetrione compounds were described. The fungicidal effects of these compounds on the mycelial growth of the isolate, Phoma eupyrena were carried out by in vitro experiment. The results show that the response to treatment depended not only on the concentration of the compounds ...

  19. Fate and distribution of pyrimethanil, metalaxyl, dichlofluanid and penconazol fungicides from treated grapes intended for winemaking.

    Science.gov (United States)

    Vaquero-Fernández, L; Sanz-Asensio, J; López-Alonso, M; Martínez-Soria, M T

    2009-02-01

    Tempranillo grapes were immersed in solutions of pyrimethanil, metalaxyl, dichlofluanid and penconazol fungicides at different concentrations for several different times. Determinations of the fungicide residues was carried out by GC-NPD, with an additional confirmation by GC-MS. The percentage absorption was determined as well as the distribution between surface, skin and pulp of the grapes. The percentage absorption ranged from 7.2 to 85.5%. These values depended on the time the grapes were in contact with the fungicide solutions. Residues were mainly found in skins, with percentages in skins ranging from 66.3 to 90.3% of total residues. In pulp, these values ranged from 3.5 to 31.0%. The overall methodology was applied to the determination of pyrimethanil in Tempranillo grapes treated with the recommended doses, respecting the safety period. Pyrimethanil residues found in treated grapes were higher in the skin. In grapes collected within the safety period (21 days), the levels found for fungicide residues were below maximum residues levels.

  20. Effect of fungicide on the development of wheat stem rust and yield ...

    African Journals Online (AJOL)

    Stem rust caused by Puccinia graminis f.sp tritici Erik. & E. Henn. is a highly destructive disease of wheat (Triticum aestivum L.). The effects of fungicide application on stem rust (Puccinia graminis tritici) epidemics and yield of three bread wheat varieties varying in reaction to the disease were studied in two major wheat ...

  1. Comparison of human health risks resulting from exposure to fungicides and mycotoxins via food

    NARCIS (Netherlands)

    Muri, S.D.; Voet, van der H.; Boon, P.E.; Klaveren, van J.D.; Bruschweiler, B.

    2009-01-01

    The interest in holistic considerations in the area of food safety is increasing. Risk managers may face the problem that reducing the risk of one compound may increase the risk of another compound. An example is the potential increase in mycotoxin levels due to a reduced use of fungicides in crop

  2. Investigations on organic fungicides; V. Chemical constitution and fungistatic activity of aliphatic bisdithiocarbamates and isothiocyanates

    NARCIS (Netherlands)

    Klöpping, H.L.; Kerk, G.J.M. van der

    1951-01-01

    In this paper, the investigations on the relations of structure to antifungal activity of sulphur compounds described in the previous publication of this series are extended to bisdithiocarbamates and isothiocyanates. The most active sulphur fungicide described in the literature so far, disodium

  3. Design, Synthesis and Fungicidal Activity of 2-Substituted Phenyl-2-oxo-, 2-Hydroxy- and 2-Acyloxyethylsulfonamides

    Directory of Open Access Journals (Sweden)

    Minlong Wang

    2017-05-01

    Full Text Available Sulfonyl-containing compounds, which exhibit a broad spectrum of biological activities, comprise a substantial proportion of and play a vital role, not only in medicines but also in agrochemicals. As a result increasing attention has been paid to the research and development of sulfonyl derivatives. A series of thirty-eight 2-substituted phenyl-2-oxo- III, 2-hydroxy- IV and 2-acyloxyethylsulfonamides V were obtained and their structures confirmed by IR, 1H-NMR, and elemental analysis. The in vitro and in vivo bioactivities against two Botrytis cinerea strains, DL-11 and HLD-15, which differ in their sensitivity to procymidone, were evaluated. The in vitro activity results showed that the EC50 values of compounds V-1 and V-9 were 0.10, 0.01 mg L−1 against the sensitive strain DL-11 and 3.32, 7.72 mg L−1 against the resistant strain HLD-15, respectively. For in vivo activity against B. cinerea, compound V-13 and V-14 showed better control effect than the commercial fungicides procymidone and pyrimethanil. The further in vitro bioassay showed that compounds III, IV and V had broad fungicidal spectra against different phytopathogenic fungi. Most of the title compounds showed high fungicidal activities, which could be used as lead compounds for further developing novel fungicidal compounds against Botrytis cinerea.

  4. Screening conventional fungicides...control of blister rust on sugar pine in California

    Science.gov (United States)

    Clarence R. Quick

    1967-01-01

    After 5 years, 4 of 14 fungicides tested showed varying pr of development into satisfactory direct control of blister rust. Little promise of systemic control was found. Trees treated were second-growth sugar pine in a mixed conifer forest in eastern Shasta County, California, where blister rust has been intensifying for many years. Most trees received basal-stem...

  5. METABOLOMIC EVALUATION OF RAT LIVER AND TESTIS TO CHARACTERIZE THE TOXICITY OF TRIAZOLE FUNGICIDES

    Science.gov (United States)

    The effects of two triazole fungicides, myclobutanil and triadimefon, on endogenous rat metabolite profiles in blood serum, liver, and testis was assessed using proton nuclear magnetic resonance (1H-NMR) spectroscopy. Adult male Sprague-Dawley rats were dosed daily by gavage for...

  6. Assessing effects of the fungicide tebuconazole to heterotrophic microbes in aquatic microcosms

    NARCIS (Netherlands)

    Dimitrov, M.R.; Kosol, Sujitra; Smidt, H.; Brink, van den P.J.; Wijngaarden, van R.P.A.; Brock, T.C.M.; Maltby, L.

    2014-01-01

    Aquatic ecological risk assessment of fungicides in Europe under Regulation 1107/2009/EC does not currently assess risk to non-target bacteria and fungi. Rather, regulatory acceptable concentrations based on ecotoxicological data obtained from studies with fish, invertebrates and primary producers

  7. Application of Copper Solid Amalgam Electrode for Determination of Fungicide Tebuconazole

    Czech Academy of Sciences Publication Activity Database

    Nováková, Kateřina; Navrátil, Tomáš; Jaklová Dytrtová, Jana; Chýlková, J.

    2013-01-01

    Roč. 8, č. 1 (2013), s. 1-16 ISSN 1452-3981 R&D Projects: GA ČR GAP206/11/1638; GA ČR(CZ) GAP208/12/1645 Institutional support: RVO:61388955 ; RVO:61388963 Keywords : tebuconazole * fungicide * copper solid amalgam electrode Subject RIV: CG - Electrochemistry Impact factor: 1.956, year: 2013

  8. Phyto-fungicides: Structure activity relationships of the thymol derivatives against Rhizoctonia solani

    Science.gov (United States)

    Thymol, the key component of thyme oil and its derivatives were evaluated for their structure activity relationship as fungicide against Rhizoctonia solani. Since plant based chemicals are considered as “Generally Recognized as Safe” (GRAS) chemicals, there is a great potential to use phytochemicals...

  9. Biosynthesis of NAD from nicotinic acid and nicotinamide by resting cells of Arthrobacter globiformis

    International Nuclear Information System (INIS)

    Kuwahara, Masaaki

    1978-01-01

    Isotopically labeled nicotinic acid and nicotinamide were incorporated into the metabolites of nicotinic acid-dependent pathway (Preiss-Handler pathway) of the NAD biosynthesis by resting cells of Arthrobacter globiformis. Azaserine and adenosine markedly stimulated the accumulation of NAD in the cells. Radioactive nicotinic acid and nicotinamide were also incorporated into an unknown compound when the cells were incubated in the presence of azaserine. Cell-free extract of the organism showed the NAD synthetase activity, which required ammonium ion and ATP for the amidation of deamido-NAD. Adenosine inhibited the enzyme activity. The organism possessed nicotinamidase, suggesting deamidation is the first step in the biosynthesis of NAD from nicotinamide. The activity was inhibited by NAD, NADP and NMN. (auth.)

  10. Synergy and Target Promiscuity Drive Structural Divergence in Bacterial Alkylquinolone Biosynthesis.

    Science.gov (United States)

    Wu, Yihan; Seyedsayamdost, Mohammad R

    2017-12-21

    Microbial natural products are genetically encoded by dedicated biosynthetic gene clusters (BGCs). A given BGC usually produces a family of related compounds that share a core but contain variable substituents. Though common, the reasons underlying this divergent biosynthesis are in general unknown. Herein, we have addressed this issue using the hydroxyalkylquinoline (HAQ) family of natural products synthesized by Burkholderia thailandensis. Investigations into the detailed functions of two analogs show that they act synergistically in inhibiting bacterial growth. One analog is a nanomolar inhibitor of pyrimidine biosynthesis and at the same time disrupts the proton motive force. A second analog inhibits the cytochrome bc 1 complex as well as pyrimidine biogenesis. These results provide a functional rationale for the divergent nature of HAQs. They imply that synergy and target promiscuity are driving forces for the evolution of tailoring enzymes that diversify the products of the HAQ biosynthetic pathway. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Colonies of Bumble Bees (Bombus impatiens Produce Fewer Workers, Less Bee Biomass, and Have Smaller Mother Queens Following Fungicide Exposure

    Directory of Open Access Journals (Sweden)

    Olivia M. Bernauer

    2015-06-01

    Full Text Available Bees provide vital pollination services to the majority of flowering plants in both natural and agricultural systems. Unfortunately, both native and managed bee populations are experiencing declines, threatening the persistence of these plants and crops. Agricultural chemicals are one possible culprit contributing to bee declines. Even fungicides, generally considered safe for bees, have been shown to disrupt honey bee development and impair bumble bee behavior. Little is known, however, how fungicides may affect bumble bee colony growth. We conducted a controlled cage study to determine the effects of fungicide exposure on colonies of a native bumble bee species (Bombus impatiens. Colonies of B. impatiens were exposed to flowers treated with field-relevant levels of the fungicide chlorothalonil over the course of one month. Colony success was assessed by the number and biomass of larvae, pupae, and adult bumble bees. Bumble bee colonies exposed to fungicide produced fewer workers, lower total bee biomass, and had lighter mother queens than control colonies. Our results suggest that fungicides negatively affect the colony success of a native bumble bee species and that the use of fungicides during bloom has the potential to severely impact the success of native bumble bee populations foraging in agroecosystems.

  12. Relationship between IC50 determined in vitro/in vivo and the fungicide rate used in the Field

    Directory of Open Access Journals (Sweden)

    Erlei Melo Reis

    2015-03-01

    Full Text Available Published data containing fungicide concentrations that control 50% (IC50 of a given fungus were analyzed. In the analysis we considered: (i the IC50 determined in vitro and in vivo for a given fungicide and for a specific fungus; (ii the concentration (g/ha of active ingredient for the fungicide indicated to control a specific disease in the field; (iii water volume of 120/L used in the spray; (iv the fungicide a.i. concentration (mg/L in 120 L volume; (v and the ratio of the concentration used in the field with that determined in the laboratory. The analysis were performed by using IC50 data for DMIs, QoIs, a carbamate and a benzimidazol against the following fungi Bipolaris sorokiniana, Drechslera tritici-repentis, D. siccans, Fusarium graminearum, Puccinia triticina, Exserohilum turcicum, Phakopsora pachyrhizi and Corynespora cassiicola. The fungicide concentrations sprayed in the field were 33.9 (D. siccans and trifloxystrobin to 500,000.0 (E. turcicum and iprodione times higher than that determined in the laboratory. It was concluded that the IC50 was not related to the concentration used in the field and therefore should be used to compare the power among fungicides and to monitor the fungal sensitivity shift towards fungicides

  13. Efficacy of Combined Formulations of Fungicides with Different Modes of Action in Controlling Botrytis Gray Mold Disease in Chickpea

    Directory of Open Access Journals (Sweden)

    M. H. Rashid

    2014-01-01

    Full Text Available Botrytis gray mold (BGM caused by Botrytis cinerea Pers. Ex. Fr. is an extremely devastating disease of chickpea (Cicer arietinum L. and has a regional as well as an international perspective. Unfortunately, nonchemical methods for its control are weak and ineffective. In order to identify an effective control measure, six fungicides with different modes of action were evaluated on a BGM susceptible chickpea variety BARIchhola-1 at a high BGM incidence location (Madaripur in Bangladesh for three years (2008, 2009, and 2010. Among the six fungicides tested, one was protectant [Vondozeb 42SC, a.i. mancozeb (0.2%], two systemic [Bavistin 50 WP, a.i. carbendazim (0.2%, and Protaf 250EC, propiconazole (0.05%], and three combination formulations [Acrobat MZ690, dimethomorph 9% + mancozeb 60%, (0.2%; Secure 600 WG, phenomadone + mancozeb (0.2%; and Companion, mancozeb 63% + carbendazim 12% (0.2%]. The results showed superiority of combination formulations involving both protectant and systemic fungicides over the sole application of either fungicide separately. Among the combination fungicides, Companion was most effective, resulting in the lowest disease severity (3.33 score on 1–9 scale and the highest increase (38% of grain yield in chickpea. Therefore, this product could be preferred over the sole application of either solo protectant or systemic fungicides to reduce yield losses and avoid fungicide resistance.

  14. Efficacy of combined formulations of fungicides with different modes of action in controlling botrytis gray mold disease in chickpea.

    Science.gov (United States)

    Rashid, M H; Hossain, M Ashraf; Kashem, M A; Kumar, Shiv; Rafii, M Y; Latif, M A

    2014-01-01

    Botrytis gray mold (BGM) caused by Botrytis cinerea Pers. Ex. Fr. is an extremely devastating disease of chickpea (Cicer arietinum L.) and has a regional as well as an international perspective. Unfortunately, nonchemical methods for its control are weak and ineffective. In order to identify an effective control measure, six fungicides with different modes of action were evaluated on a BGM susceptible chickpea variety BARIchhola-1 at a high BGM incidence location (Madaripur) in Bangladesh for three years (2008, 2009, and 2010). Among the six fungicides tested, one was protectant [Vondozeb 42SC, a.i. mancozeb (0.2%)], two systemic [Bavistin 50 WP, a.i. carbendazim (0.2%), and Protaf 250EC, propiconazole (0.05%)], and three combination formulations [Acrobat MZ690, dimethomorph 9% + mancozeb 60%, (0.2%); Secure 600 WG, phenomadone + mancozeb (0.2%); and Companion, mancozeb 63% + carbendazim 12% (0.2%)]. The results showed superiority of combination formulations involving both protectant and systemic fungicides over the sole application of either fungicide separately. Among the combination fungicides, Companion was most effective, resulting in the lowest disease severity (3.33 score on 1-9 scale) and the highest increase (38%) of grain yield in chickpea. Therefore, this product could be preferred over the sole application of either solo protectant or systemic fungicides to reduce yield losses and avoid fungicide resistance.

  15. FUNGICIDES IN SECOND HARVEST CORN: CERCOSPORIOSE CONTROL AND BLOTCH, PRODUCTIVITY, ECONOMIC RETURN AND GRAIN QUALITY

    Directory of Open Access Journals (Sweden)

    P. Rezende

    2017-10-01

    Full Text Available Os objetivos desse trabalho foram avaliar a eficiência de The aim of this study was evaluate efficacy fungicides to control cercospora leaf spot (Cercospora zeae-maydis and helminthosporium leaf blight (Exserohilumturcicum, productivity, economic returns and quality of grain of corn culture of second crop in Farm Bandeirantes at Feliz Natal/MT. The treatments evaluated were: pyraclostrobina+epoxiconazol (0,7 L ha-1, trifloxistrobina+protioconazol (0,3L ha-1, azoxistrobina+cyproconazol(0,3 L ha-1, azoxystrobina (0,25 L ha-1, trifloxistrobina+ciproconazol (0,2 L ha-1 and control. Theapplicationof products occurred when corn was with 55 days, with a high propelled sprayer. The experimental design was a randomized block, with 6 treatments and 3 replications. The severity of each disease was visually determined through periodic analyses and ten plants were marked in each repetition, which were evaluated during the entire crop cycle. The data of severity obtained were used to calculate the area under disease progress curve (AUDPC. It was also obtained the production per ha, the economic return (R$ ha-1 and physiological quality of grain was evaluated by germination tests and accelerated aging of the grains. All treatments had significant difference compared to the control sample in controlling cercospora leaf spot about the control of helminthosporiumleat blight, the fungicides trifloxystrobin+prothioconazol and trifloxystrobin+cyproconazol were not efficient, and the fungicides pyraclostrobina+epoxiconazol, azoxystrobina, azoxistrobina+cyproconazol were efficient. The treatments that had major production are from the group of triazoles+strobilurine and the fungicide pyraclostrobin+epoxyconazol showed greater economic viability. Not were differences among fungicides, and neither of the treatments compared to control, in germination and accelerated aging tests, showing that the grains have good quality characteristics

  16. Probabilities for profitable fungicide use against gray leaf spot in hybrid maize.

    Science.gov (United States)

    Munkvold, G P; Martinson, C A; Shriver, J M; Dixon, P M

    2001-05-01

    ABSTRACT Gray leaf spot, caused by the fungus Cercospora zeae-maydis, causes considerable yield losses in hybrid maize grown in the north-central United States and elsewhere. Nonchemical management tactics have not adequately prevented these losses. The probability of profitably using fungicide application as a management tool for gray leaf spot was evaluated in 10 field experiments under conditions of natural inoculum in Iowa. Gray leaf spot severity in untreated control plots ranged from 2.6 to 72.8% for the ear leaf and from 3.0 to 7.7 (1 to 9 scale) for whole-plot ratings. In each experiment, fungicide applications with propiconazole or mancozeb significantly reduced gray leaf spot severity. Fungicide treatment significantly (P fungicide applications. For one application, the probability ranged from approximately 0.06 to more than 0.99, and exceeded 0.50 in six of nine scenarios (specific experiment/hybrid). The highest probabilities occurred in the 1995 experiments with the most susceptible hybrid. Probabilities were almost always higher for a single application of propiconazole than for two applications. These results indicate that a single application of propiconazole frequently can be profitable for gray leaf spot management in Iowa, but the probability of a profitable application is strongly influenced by hybrid susceptibility. The calculation of probabilities for positive net returns was more informative than mean separation in terms of assessing the economic success of the fungicide applications.

  17. Thrombin-induced rabbit platelet microbicidal protein is fungicidal in vitro.

    Science.gov (United States)

    Yeaman, M R; Ibrahim, A S; Edwards, J E; Bayer, A S; Ghannoum, M A

    1993-03-01

    Platelet microbicidal protein (PMP) is released from platelets in response to thrombin stimulation. PMP is known to possess in vitro bactericidal activity against Staphylococcus aureus and viridans group streptococci. To determine whether PMP is active against other intravascular pathogens, we evaluated its potential fungicidal activity against strains of Candida species and Cryptococcus neoformans. Anionic resin adsorption and gel electrophoresis confirmed that the fungicidal activity of PMP resided in a small (approximately 8.5-kDa), cationic protein, identical to previous studies of PMP-induced bacterial killing (M.R. Yeaman, S.M. Puentes, D.C. Norman, and A.S. Bayer, Infect. Immun. 60:1202-1209, 1992). When assayed over a 180-min period in vitro, the susceptibilities of these fungi to PMP varied considerably. Generally, Candida albicans strains (mean survival, 33.5% +/- 6.9% [n = 6]) as well as isolates of Candida glabrata (mean survival, 50.8% +/- 2.9% [n = 2]) were the most susceptible to killing by PMP, while Candida guillermondii and Candida parapsilosis were relatively resistant to PMP-induced killing. Compared with C. albicans, C. neoformans was relatively resistant to the fungicidal activity of PMP, with a mean survival among the isolates studied of 77.4% +/- 12.4% (n = 6). Against C. albicans, PMP-induced fungicidal activity was time dependent (range, 0 to 180 min), PMP concentration dependent (range, 10 to 150 U/ml), and inversely related to the fungal inoculum (range, 5 x 10(3) to 1 x 10(5) CFU/ml). Scanning electron microscopy of PMP-exposed C. albicans and C. neoformans cells revealed extensive surface damage and collapse, suggesting that the site of PMP fungicidal action may directly or indirectly involve the fungal cell envelope.

  18. Disease control by chemical and biological fungicides in cultivated mushrooms: button mushroom, oyster mushroom and shiitake

    Directory of Open Access Journals (Sweden)

    Ivana Potočnik

    2015-12-01

    Full Text Available The most commonly cultivated basidiomycetes worldwide and in Serbia are button mushroom (Agaricus bisporus, oyster mushroom (Pleurotus sp. and shiitake (Lentinus edodes. Production of their fruiting bodies is severely afflicted by fungal, bacterial, and viral pathogens that are able to cause diseases which affect yield and quality. Major A. bisporus fungal pathogens include Mycogone perniciosa, Lecanicillium fungicola, and Cladobotryum spp., the causal agents of dry bubble, wet bubble, and cobweb disease, respectively. Various Trichoderma species, the causal agents of green mould, also affect all three kinds of edible mushrooms. Over the past two decades, green mould caused by T. aggressivum has been the most serious disease of button mushroom. Oyster mushroom is susceptible to T. pleurotum and shiitake to T. harzianum. The bacterial brawn blotch disease, caused by Pseudomonas tolaasii, is distributed globally. Disease control on mushroom farms worldwide is commonly based on the use of fungicides. However, evolution of pathogen resistance to fungicides after frequent application, and host sensitivity to fungicides are serious problems. Only a few fungicides are officially recommended in mushroom production: chlorothalonil and thiabendazol in North America and prochloraz in the EU and some other countries. Even though decreased sensitivity levels of L. fungicola and Cladobotryum mycophilum to prochloraz have been detected, disease control is still mainly provided by that chemical fungicide. Considering such resistance evolution, harmful impact to the environment and human health, special attention should be focused on biofungicides, both microbiological products based on Bacillus species and various natural substances of biological origin, together with good programs of hygiene. Introduction of biofungicides has created new possibilities for crop protection with reduced application of chemicals.

  19. Anthocyanin Biosynthesis and Degradation Mechanisms in Solanaceous Vegetables: A Review

    Science.gov (United States)

    Liu, Ying; Tikunov, Yury; Schouten, Rob E.; Marcelis, Leo F. M.; Visser, Richard G. F.; Bovy, Arnaud

    2018-01-01

    Anthocyanins are a group of polyphenolic pigments that are ubiquitously found in the plant kingdom. In plants, anthocyanins play a role not only in reproduction, by attracting pollinators and seed dispersers, but also in protection against various abiotic and biotic stresses. There is accumulating evidence that anthocyanins have health-promoting properties, which makes anthocyanin metabolism an interesting target for breeders and researchers. In this review, the state of the art knowledge concerning anthocyanins in the Solanaceous vegetables, i.e., pepper, tomato, eggplant, and potato, is discussed, including biochemistry and biological function of anthocyanins, as well as their genetic and environmental regulation. Anthocyanin accumulation is determined by the balance between biosynthesis and degradation. Although the anthocyanin biosynthetic pathway has been well-studied in Solanaceous vegetables, more research is needed on the inhibition of biosynthesis and, in particular, the anthocyanin degradation mechanisms if we want to control anthocyanin content of Solanaceous vegetables. In addition, anthocyanin metabolism is distinctly affected by environmental conditions, but the molecular regulation of these effects is poorly understood. Existing knowledge is summarized and current gaps in our understanding are highlighted and discussed, to create opportunities for the development of anthocyanin-rich crops through breeding and environmental management. PMID:29594099

  20. Anthocyanin Biosynthesis and Degradation Mechanisms in Solanaceous Vegetables: A Review

    Directory of Open Access Journals (Sweden)

    Ying Liu

    2018-03-01

    Full Text Available Anthocyanins are a group of polyphenolic pigments that are ubiquitously found in the plant kingdom. In plants, anthocyanins play a role not only in reproduction, by attracting pollinators and seed dispersers, but also in protection against various abiotic and biotic stresses. There is accumulating evidence that anthocyanins have health-promoting properties, which makes anthocyanin metabolism an interesting target for breeders and researchers. In this review, the state of the art knowledge concerning anthocyanins in the Solanaceous vegetables, i.e., pepper, tomato, eggplant, and potato, is discussed, including biochemistry and biological function of anthocyanins, as well as their genetic and environmental regulation. Anthocyanin accumulation is determined by the balance between biosynthesis and degradation. Although the anthocyanin biosynthetic pathway has been well-studied in Solanaceous vegetables, more research is needed on the inhibition of biosynthesis and, in particular, the anthocyanin degradation mechanisms if we want to control anthocyanin content of Solanaceous vegetables. In addition, anthocyanin metabolism is distinctly affected by environmental conditions, but the molecular regulation of these effects is poorly understood. Existing knowledge is summarized and current gaps in our understanding are highlighted and discussed, to create opportunities for the development of anthocyanin-rich crops through breeding and environmental management.

  1. Effects of Oxygen Limitation on the Biosynthesis of Photo Pigments in the Red Microalgae Galdieria sulphuraria Strain 074G

    NARCIS (Netherlands)

    Sarian, Fean Davisunjaya; Delicia Yunita Rahman, Delicia; Schepers, Otto; van der Maarel, Marc Jos Elise Cornelis

    2016-01-01

    As a consequence of the inhibition of one of the steps in the biosynthesis of the photopigments chlorophyll and phycobilin, the red microalga Galdieria partita excretes coproporphyrinogen III in the medium when growing on glucose. No coproporphyrinogen III was found when the closely related red

  2. Human growth hormone binding and stimulation of insulin biosynthesis in cloned rat insulinoma cells

    DEFF Research Database (Denmark)

    Billestrup, Nils

    1985-01-01

    Binding of 125I labelled human growth hormone to cloned insulin producing RIN-5AH cells is described. Binding was specific for somatotropic hormones since both human and rat growth hormone could compete for binding sites, whereas much higher concentrations of lactogenic hormones were needed to in...... to inhibit binding. Culture of RIN-5AH cells in the presence of hGH stimulated insulin biosynthesis by 85%....

  3. Occurrence and Environmental Effects of Boscalid and Other Fungicides in Three Targeted Use Areas in the United States

    Science.gov (United States)

    Reilly, T. J.; Smalling, K. L.; Wilson, E. R.

    2011-12-01

    Fungicides are typically used to control the outbreak of persistent, historically significant plant diseases like late blight (caused by Phytophthora infestans and responsible for the Irish Potato famine of 1846) and newer plant diseases like Asian Soy Rust, both of which are potentially devastating if not controlled. Of the more than 67,000 pesticide products currently registered for use in the United States, over 3,600 are used to combat fungal diseases. Although they are widely used, relatively little is known about the fate and potential secondary effects of fungicides in the aquatic environment. Even less is known about the fate and environmental occurrence of recently registered fungicides including boscalid, which was first registered for use in the US in 2003. Unlike most other pesticides, multiple fungicides are typically applied as a prophylactic crop protectant upwards of ten times per season (depending upon conditions and crop type), but at lower application rates than herbicides or insecticides. This difference in usage increases the likelihood of chronic exposure of aquatic ecosystems to low concentrations of fungicides. Using a newly developed analytical method, the U.S. Geological Survey measured 33 fungicides in surface water and shallow groundwater in three geographic areas of intense fungicide use across the US. Sampling sites were selected near or within farms using prophylactic fungicides at rates and types typical of the crop type and their geographic location. At least one fungicide was detected in 75% of the surface waters (n=60) and 58% of the groundwater (n=12) samples. Twelve fungicides were detected in surface- and groundwater including boscalid (72%), azoxystrobin (51%), pyraclostrobin (40%), chlorothalonil (38%) and pyrimethanil (28%). Boscalid was the most frequently detected pesticide and has not been previously documented in the aquatic environment. In this study, an average of 44% of the pesticide concentration in a water sample

  4. Ergosterol biosynthesis and drug development for Chagas disease

    Directory of Open Access Journals (Sweden)

    Julio A Urbina

    2009-07-01

    Full Text Available This article presents an overview of the currently available drugs nifurtimox (NFX and benznidazole (BZN used against Trypanosoma cruzi, the aetiological agent of Chagas disease; herein we discuss their limitations along with potential alternatives with a focus on ergosterol biosynthesis inhibitors (EBI. These compounds are currently the most advanced candidates for new anti-T. cruzi agents given that they block de novo production of 24-alkyl-sterols, which are essential for parasite survival and cannot be replaced by a host's own cholesterol. Among these compounds, new triazole derivatives that inhibit the parasite's C14± sterol demethylase are the most promising, as they have been shown to have curative activity in murine models of acute and chronic Chagas disease and are active against NFX and BZN-resistant T. cruzi strains; among this class of compounds, posaconazole (Schering-Plough Research Institute and ravuconazole (Eisai Company are poised for clinical trials in Chagas disease patients in the short term. Other T. cruzi-specific EBI, with in vitro and in vivo potency, include squalene synthase, lanosterol synthase and squalene epoxidase-inhibitors as well as compounds with dual mechanisms of action (ergosterol biosynthesis inhibition and free radical generation, but they are less advanced in their development process. The main putative advantages of EBI over currently available therapies include their higher potency and selectivity in both acute and chronic infections, activity against NFX and BZN-resistant T. cruzi strains, and much better tolerability and safety profiles. Limitations may include complexity and cost of manufacture of the new compounds. As for any new drug, such compounds will require extensive clinical testing before being introduced for clinical use, and the complexity of such studies, particularly in chronic patients, will be compounded by the current limitations in the verification of true parasitological cures for

  5. Aluminum Phosphide; the Most Fatal Rodenticide and Fungicide

    International Nuclear Information System (INIS)

    Afshari, R.

    2007-01-01

    Introduction: Aluminum phosphide (AP) is a fumigate agent, which is also used to control rodents and pests in grain storage facilities. This agent is commonly used in low income and agricultural communities. AP is easily available, cheap and highly toxic. Ingestion of even half a fresh tablet invariably results in death. Its suicidal or accidental poisoning is a medical emergency, while in some low income countries it reaches to more than two third of poisoning deaths. Methods: PubMed was systematically searched (December 2006) for articles related to aluminium phosphide poisoning. 24 articles were finally included. Mechanism of action; AP on exposure to moisture, liberates highly toxic gas, phosphine. In animal and human models AP rapidly inhibits cytochrome-c oxidase leading to inhibition of mitochondrial oxidative phosphorylation and inhibits mitochondrial respiration and has cytotoxic action. Clinical Findings: Initial findings of intoxication may be nonspecific and transient. The symptoms may resolve within several hours after removal from exposure. It, however, produces phosphine gas, which is a mitochondrial poison. Its manufacturing and application pose risks of inhalation of phosphine. CNS; GCS is fine at the beginning. Biochemistry; Metabolic acidosis and liver dysfunction are reported. Shock is frequent. Respiratory Tract; Acute dyspnoea, hypotension, bradycardia and other signs of intoxication were also stated. Gastrointestinal; Reported short-segment esophageal strictures in the upper and mid esophagus, successfully managed by endoscopic dilatation. In sub-chronic use, degenerative changes in liver, heart and kidney of rabbits are reported. Cardiovascular; The ECG abnormalities are common and include hypotension, bradycardia, ST-T changes, Supraventricular tachycardia, ventricular ectopics, life threatening ventricular tachycardia, ventricular fibrillation, atrial flutter/fibrillation, variable degrees of heart block and toxic myocarditis. Haematologic

  6. The Spatial Organization of Glucosinolate Biosynthesis

    DEFF Research Database (Denmark)

    Nintemann, Sebastian

    between the individual classes of glucosinolates under constitutive and induced conditions and identified the source tissues of these defense compounds. Protein-protein interaction studies were carried out to investigate the subcellular organization of glucosinolate biosynthesis. We identified a family...... resistance and nutritional value and many plant specialized metabolites are of high value due to their health promoting characteristics. Glucosinolates are defense compounds found in many crops from the Brassicaceae family and are of high interest because of their nutritional and antinutritional properties...... cells is an open question. Likewise, it is not known how glucosinolate biosynthesis is orchestrated at the subcellular level. These open questions were addressed with several approaches in this project, with the aim of shedding light on the spatial organization of glucosinolate biosynthesis from...

  7. Fungicide-driven evolution and molecular basis of multidrug resistance in field populations of the grey mould fungus Botrytis cinerea

    NARCIS (Netherlands)

    Kretschmer, M.; Leroch, M.; Mosbach, A.; Walker, A.S.; Fillinger, S.; Mernke, D.; Schoonbeek, H.J.; Pradier, J.M.; Leroux, P.; Waard, de M.A.; Hahn, M.

    2009-01-01

    The grey mould fungus Botrytis cinerea causes losses of commercially important fruits, vegetables and ornamentals worldwide. Fungicide treatments are effective for disease control, but bear the risk of resistance development. The major resistance mechanism in fungi is target protein modification

  8. Determination of tetrahydrophtalimide and 2-thiothiazolidine-4-carboxylic acid, urinary metabolites of the fungicide captan, in rats and humans

    NARCIS (Netherlands)

    van Welie, R.T.H.; van Duyn, P; Lamme, E K; Jäger, P; van Baar, B L; Vermeulen, N P

    1991-01-01

    Capillary gas chromatographic (GC) methods using sulphur and mass selective detection for the qualitative and quantitative determination of tetrahydrophtalimide (THPI) and 2-thiothiazolidine-4-carboxylic acid (TTCA), urinary metabolites of the fungicide captan in rat and humans, were developed.

  9. A new mechanism for reduced sensitivity to demethylation-inhibitor fungicides in the fungal banana black Sigatoka pathogen Pseudocercospora fijiensis

    NARCIS (Netherlands)

    Díaz-Trujillo, C.; Chong, P.; Stergiopoulos, I.; Meijer, H.J.G.; Wit, de P.J.G.M.; Kema, G.H.J.

    2017-01-01

    The Dothideomycete Pseudocercospora fijiensis, previously Mycosphaerella fijiensis, is the causal agent of black Sigatoka, one of the most destructive diseases of bananas and plantains. Disease management depends on fungicide applications with a major share for sterol demethylation-inhibitors

  10. GENE EXPRESSION PROFILING IN THE LIVER OF CD-1 MICE TO CHARACTERIZE THE HEPATOTOXICITY OF TRIAZOLE FUNGICIDES

    Science.gov (United States)

    Four triazole fungicides used in agricultural or pharmaceutical applications were examined for hepatotoxic effects in mouse liver. Besides organ weight, histopathology, and cytochrome P450 (CYP) enzyme induction, DNA microarrays were used to generate gene expression profiles and ...

  11. Functional and Evolutionary Relationship between Arginine Biosynthesis and Prokaryotic Lysine Biosynthesis through α-Aminoadipate

    Science.gov (United States)

    Miyazaki, Junichi; Kobashi, Nobuyuki; Nishiyama, Makoto; Yamane, Hisakazu

    2001-01-01

    Our previous studies revealed that lysine is synthesized through α-aminoadipate in an extremely thermophilic bacterium, Thermus thermophilus HB27. Sequence analysis of a gene cluster involved in the lysine biosynthesis of this microorganism suggested that the conversion from α-aminoadipate to lysine proceeds in a way similar to that of arginine biosynthesis. In the present study, we cloned an argD homolog of T. thermophilus HB27 which was not included in the previously cloned lysine biosynthetic gene cluster and determined the nucleotide sequence. A knockout of the argD-like gene, now termed lysJ, in T. thermophilus HB27 showed that this gene is essential for lysine biosynthesis in this bacterium. The lysJ gene was cloned into a plasmid and overexpressed in Escherichia coli, and the LysJ protein was purified to homogeneity. When the catalytic activity of LysJ was analyzed in a reverse reaction in the putative pathway, LysJ was found to transfer the ɛ-amino group of N2-acetyllysine, a putative intermediate in lysine biosynthesis, to 2-oxoglutarate. When N2-acetylornithine, a substrate for arginine biosynthesis, was used as the substrate for the reaction, LysJ transferred the δ-amino group of N2-acetylornithine to 2-oxoglutarate 16 times more efficiently than when N2-acetyllysine was the amino donor. All these results suggest that lysine biosynthesis in T. thermophilus HB27 is functionally and evolutionarily related to arginine biosynthesis. PMID:11489859

  12. Sterol Biosynthesis Pathway as Target for Anti-trypanosomatid Drugs

    Directory of Open Access Journals (Sweden)

    Wanderley de Souza

    2009-01-01

    Full Text Available Sterols are constituents of the cellular membranes that are essential for their normal structure and function. In mammalian cells, cholesterol is the main sterol found in the various membranes. However, other sterols predominate in eukaryotic microorganisms such as fungi and protozoa. It is now well established that an important metabolic pathway in fungi and in members of the Trypanosomatidae family is one that produces a special class of sterols, including ergosterol, and other 24-methyl sterols, which are required for parasitic growth and viability, but are absent from mammalian host cells. Currently, there are several drugs that interfere with sterol biosynthesis (SB that are in use to treat diseases such as high cholesterol in humans and fungal infections. In this review, we analyze the effects of drugs such as (a statins, which act on the mevalonate pathway by inhibiting HMG-CoA reductase, (b bisphosphonates, which interfere with the isoprenoid pathway in the step catalyzed by farnesyl diphosphate synthase, (c zaragozic acids and quinuclidines, inhibitors of squalene synthase (SQS, which catalyzes the first committed step in sterol biosynthesis, (d allylamines, inhibitors of squalene epoxidase, (e azoles, which inhibit C14α-demethylase, and (f azasterols, which inhibit Δ24(25-sterol methyltransferase (SMT. Inhibition of this last step appears to have high selectivity for fungi and trypanosomatids, since this enzyme is not found in mammalian cells. We review here the IC50 values of these various inhibitors, their effects on the growth of trypanosomatids (both in axenic cultures and in cell cultures, and their effects on protozoan structural organization (as evaluted by light and electron microscopy and lipid composition. The results show that the mitochondrial membrane as well as the membrane lining the protozoan cell body and flagellum are the main targets. Probably as a consequence of these primary effects, other important changes take

  13. The interactive effect of fungicide residues and yeast assimilable nitrogen on fermentation kinetics and hydrogen sulfide production during cider fermentation

    OpenAIRE

    Boudreau, Thomas F; Peck, Gregory M; O'Keefe, Sean F; Stewart, Amanda C

    2016-01-01

    Abstract BACKGROUND Fungicide residues on fruit may adversely affect yeast during cider fermentation, leading to sluggish or stuck fermentation or the production of hydrogen sulfide (H2S), which is an undesirable aroma compound. This phenomenon has been studied in grape fermentation but not in apple fermentation. Low nitrogen availability, which is characteristic of apples, may further exacerbate the effects of fungicides on yeast during fermentation. The present study explored the effects of...

  14. Chemical Fungicide Pretreatment and Cool–Wet Storage Prolonging Seed Longevity in Pachira macrocarpa (Cham. & Schl.) Schl.

    OpenAIRE

    Shen, Rong–Show; Lu, Shao–Wei; Hsu, Shan–Te; Huang, Kuang–Liang; Miyajima, Ikuo

    2014-01-01

    Production of Pachira macrocarpa seeds in Taiwan is concentrated in the summer and winter months. Furthermore, the seeds harvested are difficult to store or recalcitrant. To resolve the problem of supplying seeds throughout the year, this study explores the effects that fungicide pretreatment and storage temperature have on the storage longevity of P. macrocarpa seeds, and develops effective and practical seed storage technology. The seeds were pretreated with the fungicides benomyl and carbe...

  15. Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants

    Science.gov (United States)

    Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

    2016-01-01

    Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity. PMID:26744061

  16. Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants.

    Science.gov (United States)

    Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

    2016-01-08

    Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity.

  17. Nucleoside antibiotics: biosynthesis, regulation, and biotechnology.

    Science.gov (United States)

    Niu, Guoqing; Tan, Huarong

    2015-02-01

    The alarming rise in antibiotic-resistant pathogens has coincided with a decline in the supply of new antibiotics. It is therefore of great importance to find and create new antibiotics. Nucleoside antibiotics are a large family of natural products with diverse biological functions. Their biosynthesis is a complex process through multistep enzymatic reactions and is subject to hierarchical regulation. Genetic and biochemical studies of the biosynthetic machinery have provided the basis for pathway engineering and combinatorial biosynthesis to create new or hybrid nucleoside antibiotics. Dissection of regulatory mechanisms is leading to strategies to increase the titer of bioactive nucleoside antibiotics. Copyright © 2014. Published by Elsevier Ltd.

  18. Combinatorial Biosynthesis of Polyketides – A Perspective

    Science.gov (United States)

    Wong, Fong T.; Khosla, Chaitan

    2012-01-01

    Since their discovery, polyketide synthases have been attractive targets of biosynthetic engineering to make “unnatural” natural products. Although combinatorial biosynthesis has made encouraging advances over the past two decades, the field remains in its infancy. In this enzyme-centric perspective, we discuss the scientific and technological challenges that could accelerate the adoption of combinatorial biosynthesis as a method of choice for the preparation of encoded libraries of bioactive small molecules. Borrowing a page from the protein structure prediction community, we propose a periodic challenge program to vet the most promising methods in the field, and to foster the collective development of useful tools and algorithms. PMID:22342766

  19. Method for determining heterologous biosynthesis pathways

    KAUST Repository

    Gao, Xin

    2017-08-10

    The present invention relates to a method and system for dynamically analyzing, determining, predicting and displaying ranked suitable heterologous biosynthesis pathways for a specified host. The present invention addresses the problem of finding suitable pathways for the endogenous metabolism of a host organism because the efficacy of heterologous biosynthesis is affected by competing endogenous pathways. The present invention is called MRE (Metabolic Route Explorer), and it was conceived and developed to systematically and dynamically search for, determine, analyze, and display promising heterologous pathways while considering competing endogenous reactions in a given host organism.

  20. Convergent Evolution of Ergothioneine Biosynthesis in Cyanobacteria.

    Science.gov (United States)

    Liao, Cangsong; Seebeck, Florian P

    2017-11-02

    Biosynthesis of N-α-trimethyl-2-thiohistidine (ergothioneine) is a frequent trait in cyanobacteria. This sulfur compound may provide essential relief from oxidative stress related to oxygenic photosynthesis. The central steps in ergothioneine biosynthesis are catalyzed by a histidine methyltransferase and an iron-dependent sulfoxide synthase. In this report, we present evidence that some cyanobacteria recruited and adapted a sulfoxide synthase from a different biosynthetic pathway to make ergothioneine. The discovery of a second origin of ergothioneine production underscores the physiological importance of this metabolite and highlights the evolutionary malleability of the thiohistidine biosynthetic machinery. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. An Unusual Protector-Protégé Strategy for the Biosynthesis of Purine Nucleoside Antibiotics.

    Science.gov (United States)

    Wu, Pan; Wan, Dan; Xu, Gudan; Wang, Gui; Ma, Hongmin; Wang, Tingting; Gao, Yaojie; Qi, Jianzhao; Chen, Xiaoxia; Zhu, Jian; Li, Yong-Quan; Deng, Zixin; Chen, Wenqing

    2017-02-16

    Pentostatin (PTN, deoxycoformycin) and arabinofuranosyladenine (Ara-A, vidarabine) are purine nucleoside antibiotics used clinically to treat hematological cancers and human DNA virus infections, respectively. PTN has a 1,3-diazepine ring, and Ara-A is an adenosine analog with an intriguing epimerization at the C-2' hydroxyl group. However, the logic underlying the biosynthesis of these interesting molecules has long remained elusive. Here, we report that the biosynthesis of PTN and Ara-A employs an unusual protector-protégé strategy. To our surprise, we determined that a single gene cluster governs PTN and Ara-A biosynthesis via two independent pathways. Moreover, we verified that PenB functions as a reversible oxidoreductase for the final step of PTN. Remarkably, we provided the first direct biochemical evidence that PTN can protect Ara-A from deamination by selective inhibition of the host adenosine deaminase. These findings expand our knowledge of natural product biosynthesis and open the way for target-directed genome mining of Ara-A/PTN-related antibiotics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Biosynthesis of silver nanoparticles by Aspergillus niger , Fusarium ...

    African Journals Online (AJOL)

    ... scanning electron microscope (SEM). Results indicate the synthesis of silver nanoparticles in the reaction mixture. The synthesis of nanoparticles would be suitable for developing a microbial nanotechnology biosynthesis process for mass scale production. Keywords: Silver nanoparticles, biosynthesis, fungi, Aspergillus.

  3. Ranking of fungicides according to risk assessments for health and environment

    DEFF Research Database (Denmark)

    Jørgensen, Lise Nistrup; Ørum, Jens Erik

    2014-01-01

    been introduced as the basis for a new tax system for pesticides from 1 July 2013, replacing the old value based tax. The Government has asked for a 40% reduction in the PL per ha by 2015, based on substitutions to less harmfull products. As certain pesticide groups will be favoured by the new tax......Denmark has introduced a new indicator for ranking the potential impact of pesticides on health and environment. The new Pesticide Load (PL) makes it possible for farmers to choose the least harmful fungicides and substitute between products which have an equally good efficacy profile. In practice...... PL varies for fungicide standard rates by a factor of 10. Products including epoxiconazole generally have higher PL's due to the human health profile of this active. PL's per area, crop or product will supplement the previous pesticide statistics based on treatment frequency index (TFI). PL has also...

  4. Translocation and metabolism of the fungicide Metalaxyl in rangpur lime seedlings

    International Nuclear Information System (INIS)

    Musumeci, M.R.; Ruegg, E.F.

    1984-01-01

    The application of 14 C-metalaxyl to leaves of two and six month-old Rangpur lime (Citrus limonia Osb.) seedlings is studied. In a basal foliar application, 85% of the fungicide remained in the applied leaves, though translocation was verified to upper leaves, stems and roots. When metalaxyl was applied in upper leaves only traces of radiocarbon were detected in roots and stems. After 30 days in the two-and six-month old plants, 70% of the radiocarbon corresponded to the applied fungicide Metalaxyl was degraded in leave tissues to N-(2-methoxyacetil)-N-(2,6-xylyl)-DL-alanine and two others unidentified metabolites. Polar compounds were also detected. Only 1.5% of the radiocarbon was detected as bound residue, not extracted by the acetone extraction. (Author) [pt

  5. Translocation and metabolism of the fungicide Metalaxyl in rangpur lime seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Musumeci, M.R.; Ruegg, E.F. (Instituto Biologico, Sao Paulo (Brazil). Centro de Radioisotopos)

    1984-08-01

    The application of /sup 14/C-metalaxyl to leaves of two and six month-old Rangpur lime (Citrus limonia Osb.) seedlings is studied. In a basal foliar application, 85% of the fungicide remained in the applied leaves, though translocation was verified to upper leaves, stems and roots. When metalaxyl was applied in upper leaves only traces of radiocarbon were detected in roots and stems. After 30 days in the two-and six-month old plants, 70% of the radiocarbon corresponded to the applied fungicide Metalaxyl was degraded in leave tissues to N-(2-methoxyacetil)-N-(2,6-xylyl)-DL-alanine and two others unidentified metabolites. Polar compounds were also detected. Only 1.5% of the radiocarbon was detected as bound residue, not extracted by the acetone extraction.

  6. Preliminary Trials on Treatment of Esca-Infected Grapevines with Trunk Injection of Fungicides

    Directory of Open Access Journals (Sweden)

    T. Dula

    2007-04-01

    Full Text Available An increase in trunk diseases (due to esca, Agrobacterium, rugose wood virus, leaf roll viruses, phytoplasma etc. leading to young vines death is a very serious worry in vineyards in Hungary, as it is in other countries. In response to a demand expressed by grapevine growers, a method was tested for the direct treatment of pathogens in wood tissue. An experiment based on trunk injection was carried out in an esca infected vineyard. The various fungicides (propiconazole, difenoconazole, thiabendazole; propiconazole+ thiabendazole were injected into the trunk before the beginning of the xylem sap flow at high pressure. As a result the number of symptomatic plants was decreased, and the vigour of the plants was not impaired by the fungicide ingredients. The combination difenoconazole+ thiabendazole showed the best result.

  7. Fungicidal control of Lophodermium seditiosum on Pinus sylvestris seedlings in Swedish forest nurseries

    Energy Technology Data Exchange (ETDEWEB)

    Stenstroem, Elna [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Mycology and Pathology; Arvidsson, Bernt [Svenska Skogsplantor AB, Joenkoeping (Sweden)

    2001-07-01

    During the 1990s, there were serious outbreaks of the pathogen Lophodermium seditiosum on pine seedlings in Swedish forest nurseries, even though the seedlings had been treated with the fungicide propiconazole. The present experiment was carried out to evaluate two other fungicides, fluazinam and azoxystrobin, as possible alternatives to propiconazole. In the tests, which were all carried out in the same forest nursery, seedlings were treated with either propiconazole, fluazinam. or azoxystrobin, and the proportion of needles with ascocarps of L. seditiosum and the number of ascocarps per needle were recorded over the following 2 yrs. Seedlings treated with azoxystrobin already appeared healthier than control seedlings in September of the first year, and by November all azoxystrobin-treated seedlings had fewer ascocarps per needle compared with control seedlings. In autumn of the second year, there were no ascocarps on seedlings treated with fluazinam or azoxystrobin, whereas seedlings treated with propiconazole had similar numbers of ascocarps to non-treated control seedlings.

  8. In vitro and in vivo screening of azole fungicides for antiandrogenic effects

    DEFF Research Database (Denmark)

    Taxvig, Camilla; Vinggaard, Anne; Hass, Ulla

    and antiandrogenic effects both in vitro and in vivo. Two other azole fungicides, tebuconazole and epoxiconazole, have now been investigated for antiandrogenic effects in vitro and in vivo as well. The fungicides were screened in two well-established cell assays, including testing for agonistic and antagonistic...... effects on AR in transfected CHO cells, using an AR reporter gene assay. The compounds were also analyzed for effects on steroidogenesis in H295R cells, a human adrenocorticocarcinoma cell line, used to detect effects on steroid production. In vitro tebuconazole and epoxiconazole proved to be antagonists...... signs of feminization of the male offspring were investigated. Tebuconazole caused an increase in testicular 17alfa-hydroxyprogesterone and progesterone levels, and a decrease in testosterone levels in male fetuses. Epoxiconazole had no effect on any of the mesured hormonelevels. Furthermore...

  9. Evaluating the combined efficacy of polymers with fungicides for protection of museum textiles against fungal deterioration in Egypt.

    Science.gov (United States)

    Abdel-Kareem, Omar

    2010-01-01

    Fungal deterioration is one of the highest risk factors for damage of historical textile objects in Egypt. This paper represents both a study case about the fungal microflora deteriorating historical textiles in the Egyptian Museum and the Coptic museum in Cairo, and evaluation of the efficacy of several combinations of polymers with fungicides for the reinforcement of textiles and their prevention against fungal deterioration. Both cotton swab technique and biodeteriorated textile part technique were used for isolation of fungi from historical textile objects. The plate method with the manual key was used for identification of fungi. The results show that the most dominant fungi isolated from the tested textile samples belong to Alternaria, Aspergillus, Chaetomium, Penicillium and Trichoderma species. Microbiological testing was used for evaluating the usefulness of the suggested conservation materials (polymers combined with fungicides) in prevention of the fungal deterioration of ancient Egyptian textiles. Textile samples were treated with 4 selected polymers combined with two selected fungicides. Untreated and treated textile samples were deteriorated by 3 selected active fungal strains isolated from ancient Egyptian textiles. This study reports that most of the tested polymers combined with the tested fungicides prevented the fungal deterioration of textiles. Treatment of ancient textiles by suggested polymers combined with the suggested fungicides not only reinforces these textiles, but also prevents fungal deterioration and increases the durability of these textiles. The tested polymers without fungicides reduce the fungal deterioration of textiles but do not prevent it completely.

  10. Changes in antioxidants potential, secondary metabolites and plant hormones induced by different fungicides treatment in cotton plants.

    Science.gov (United States)

    Mohamed, Heba Ibrahim; Akladious, Samia Ageeb

    2017-10-01

    The use of fungicides for an effective control of plant diseases has become crucial in the last decades in the agriculture system. Seeds of cotton plants were treated with systemic and contact fungicides to study the efficiency of seed dressing fungicides in controlling damping off caused by Rhizoctonia solani under greenhouse conditions and its effect on plant growth and metabolism. The results showed that Mon-cut showed the highest efficiency (67.99%) while each of Tondro and Hemixet showed the lowest efficiency (31.99%) in controlling damping off. Rhizolex T, Mon-cut and Tondro fungicides caused significant decrease in plant height, dry weight of plant, phytohormones, photosynthetic pigments, soluble sugars, soluble proteins, total free amino acids but caused significant increases in total phenols, flavonoids, antioxidant enzymes, ascorbic acid, reduced glutathione, MDA and hydrogen peroxide as compared with untreated plants. On the other hand, the other fungicides (Maxim, Hemixet and Flosan) increased all the above recorded parameters as compared with untreated plants. Our results indicated that the fungicides application could be a potential tool to increase plant growth, the antioxidative defense mechanisms and decreased infection with plant diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Concentration levels of new-generation fungicides in throughfall released by foliar wash-off from vineyards.

    Science.gov (United States)

    Pérez-Rodríguez, P; Soto-Gómez, D; Paradelo, M; López-Periago, J E

    2017-12-01

    The presence of agricultural pesticides in the environment and their effects on ecosystems are major concerns addressed in a significant number of articles. However, limited information is available on the pesticide concentrations released from crops. This study reports losses of new-generation fungicides by foliar wash-off from vineyards and their potential impact on the concentrations of their main active substances (AS) in surface waters. Two experimental plots devoted to vineyards were treated with various combinations of commercial new-generation fungicide formulations. Then, up to sixteen throughfall collectors were installed under the canopy. Concentrations of sixteen different AS in throughfall were determined along nine rainfall episodes. Concentrations in throughfall far exceeded the maximum permissible levels for drinking water established by the European Union regulations. Dynamics of fungicide release indicated a first-flush effect in the wash-off founding the highest concentrations of AS in the first rain episodes after application of the fungicides. This article shows that foliar spray application of commercial formulations of new-generation fungicides does not prevent the release of their AS to soil or the runoff. Concentration data obtained in this research can be valuable in supporting the assessment of environmental effects of new-generation fungicides and modeling their environmental fate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Temporal analysis and fungicide management strategies to control mango anthracnose epidemics in Guerrero, Mexico

    OpenAIRE

    Monteon Ojeda, Abraham; Mora Aguilera, José Antonio; Villegas Monter, Ángel; Nava Diaz, Cristian; Hernández Castro, Elías; Otero-Colina, Gabriel; Hernández Morales, Javier

    2012-01-01

    The temporal progress of anthracnose (Colletotrichum gloeosporioides) epidemics was studied in mango (Mangifera indica) orchards treated with fungicides from different chemical groups, mode of action, and application sequences in two regions of contrasting climates (sub-humid and dry tropics) in Guerrero, Mexico. Full flowering, initial setting, and 8-15mm Ø fruits were identified as critical stages for infection. Epidemics started 20-26 days after swollen buds, and maximum severity was attai...

  13. Joint use of fungicides, insecticides and inoculants in the treatment of soybean seeds

    Directory of Open Access Journals (Sweden)

    Yara Cristiane Buhl Gomes

    Full Text Available ABSTRACT The interference of the joint application of pesticides with seed inoculation on the survival of Bradyrhizobium has been reported in the last years. So, the objective of this study was to evaluate the joint use of fungicides, insecticides and inoculant in the treatment of soybean seeds on various parameters of Bradyrhizobium nodulation in soybean as well as on crop productivity parameters. The experiment was conducted during the 2013/2014 crop in the experimental field of the Instituto Federal de Educação, Ciência e Tecnologia de Mato Grosso - Campo Novo do Parecis Campus. The seeds of TMG 133 RR variety were sown in pots. It was used a randomized block design in a 4 x 4 + 1 factorial, four fungicides (1: fludioxonil + metalaxyl-M, 2: carboxine + thiram, 3: difeconazole and 4: carbendazim + thiram, four insecticides (1: fipronil 250 SC, 2: thiamethoxam, 3: imidacloprid + thiodicarpe and 4: imodacloprid 600 FC and an inoculant (SEMIA 5079 and SEMIA 5080, common to all treatments, with three replications. The experiment was not repeated. The joint application of fungicide and insecticide with inoculant does not affect nodulation, foliar N content and vegetative growth of the plants as well as the masses of grains per plant and 100-grain mass. The use of the carbendazim + thiram mixed with fipronil and carbendazim + thiram mixed with imidacloprid provides less number of pods per plant and grains per plant, reflecting in reductions in the production of soybean grains. In this way, the fungicide carbendazim + thiram, regardless of the combined applied insecticide, is the most harmful to Bradyrhizobium spp.

  14. Determination of acid dissociation constants of triazole fungicides by pressure assisted capillary electrophoresis

    Czech Academy of Sciences Publication Activity Database

    Konášová, Renáta; Jaklová Dytrtová, Jana; Kašička, Václav

    2015-01-01

    Roč. 1408, Aug 21 (2015), s. 243-249 ISSN 0021-9673 R&D Projects: GA ČR(CZ) GA13-17224S; GA ČR GP13-21409P Institutional support: RVO:61388963 Keywords : triazole fungicides * acid dissociation constant * pK(a) * capillary electrophoresis * ionic mobility Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 3.926, year: 2015

  15. Potential demal exposure of florists to fungicide residues on flowers and risk assessment

    OpenAIRE

    Toumi, Khaoula; Joly, L.; Vleminckx, C.; Schiffers, Bruno

    2017-01-01

    Flowers are susceptible to many pests and diseases. Therefore, they can be sprayed several times during their growth considering that no MRL are set for flow-ers. High levels of pesticide residues potentially expose daily the florists who han-dle cut flowers and possibly could endanger their health. A study was carried out to evaluate the risk for florists exposed to fungicide residues during normal profes-sional tasks. Cotton gloves were distributed to 20 florists (two pairs to each florist)...

  16. Conventional and molecular assays aid diagnosis of crop diseases and fungicide resistance

    OpenAIRE

    Michailides, Themis J.; Morgan, David P.; Ma, Zhonghua; Luo, Yong; Felts, Daniel; Doster, Mark A.; Reyes, Heraclio

    2005-01-01

    For the past decade, we have been developing techniques for monitoring pre- and postharvest diseases of tree fruit, nuts and vines at the UC Kearney Research and Extension Center (KREC). We have also advanced new methods to monitor pathogen resistance to fungicides, which growers can now use to make decisions on disease management. Although accurate, the conventional techniques are time-consuming and only provide results after 5 to 21 days. Molecular methods offer the possibility of faster, m...

  17. Quality of soybean seeds treated with fungicides and insecticides before and after storage

    OpenAIRE

    Ferreira, Thaís Francielle; Oliveira, João Almir; Carvalho, Rafaela Aparecida de; Resende, Laís Sousa; Lopes, Cassiano Gabriel Moreira; Ferreira, Valquíria de Fátima

    2016-01-01

    Abstract: The timing of seed treatment application is important to keep soybean seeds quality. Therefore, the aim of this study was verify the effect of fungicides and insecticides treatment in soybean seeds quality before and after storage. Seeds of NS 7494, NS 8693 and NS 7338 IPRO were utilized and analyses separately, through a factorial scheme 3x6, with three application moments: treated and assessed; treated, stored and assessed; stored, treated and assessed; and six combination of fung...

  18. The effect of the fungicide captan on Saccharomyces cerevisiae and wine fermentation

    OpenAIRE

    Scariot Fernando J.; Jahn Luciane M.; Delamare Ana Paula L.; Echeverrigaray Sergio

    2016-01-01

    Fungicides, particularly those used during grape maturation, as captan, can affect the natural yeast population of grapes, and can reach grape must affecting wine fermentation. The objective of the present work was to study the effect of captan on the viability and fermentative behavior of S. cerevisiae. S. cerevisiae (BY4741) on exponential phase was treated with captan (0 to 40 μM) for different periods, and their cell viability analyzed. Cell membrane integrity, thiols concentration, and r...

  19. Translocation and degradation of tebuconazole and prothioconazole in wheat following fungicide treatment at flowering.

    Science.gov (United States)

    Lehoczki-Krsjak, Szabolcs; Varga, Mónika; Szabó-Hevér, Ágnes; Mesterházy, Ákos

    2013-11-01

    Prothioconazole and tebuconazole are among the most effective fungicides against Fusarium head blight (FHB) of wheat (Triticum aestivum L.). The translocation between the ears and the flag leaves and the kinetics of degradation may influence field efficacy of these active ingredients (AIs). In greenhouse experiments, only traces (tebuconazole. Cultivar and environmental effects influenced the degradation kinetics of these AIs, but a high level of protection against FHB was maintained. © 2013 Society of Chemical Industry.

  20. Triazole fungicides can induce cross-resistance to medical triazoles in Aspergillus fumigatus.

    OpenAIRE

    Snelders, E.; Camps, S.M.T.; Karawajczyk, A.; Schaftenaar, G.; Kema, G.H.; Lee, H.A.L. van der; Klaassen, C.H.; Melchers, W.J.G.; Verweij, P.E.

    2012-01-01

    BACKGROUND: Azoles play an important role in the management of Aspergillus diseases. Azole resistance is an emerging global problem in Aspergillus fumigatus, and may develop through patient therapy. In addition, an environmental route of resistance development has been suggested through exposure to 14alpha-demethylase inhibitors (DMIs). The main resistance mechanism associated with this putative fungicide-driven route is a combination of alterations in the Cyp51A-gene (TR(34)/L98H). We invest...

  1. Effects of the hydrogen potential and fungicide treatment on Pitaya seed germination

    Directory of Open Access Journals (Sweden)

    Thiago Alberto Ortiz

    2014-11-01

    Full Text Available The objective of the present study was to evaluate pitaya seed germination under different hydrogen potentials, with or without fungicide treatment. A completely randomized design was employed under a 3 x 13 x 2 factorial scheme, corresponding to three pitaya species (white pitaya, pitaya hybrid I, pitaya hybrid II, thirteen hydrogen potentials (3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5, and 9.0 and two fungicide conditions (presence and absence, with four replications. The percentage of germination, germination speed index and mean germination time were evaluated. The data were subjected to ANOVA, and the means were compared using the Scott-Knott test (p < 0.05. The pH influenced the germination speed index in white pitaya. The mean germination time was affected by the pH levels for white pitaya and pitaya hybrid II. The fungicide did not increase the germination percentage in the evaluated species.

  2. Modeling losses of copper-based fungicide foliar sprays in wash-off under simulated rain

    DEFF Research Database (Denmark)

    Pérez-Rodríguez, P.; Paradelo Pérez, Marcos; Soto-Gómez, D.

    2015-01-01

    Wash-off experiments of three Cu-based fungicides were conducted with a single raindrop simulator with known drop size and fall height. Losses were quantified as total Cu (CuT), in solution (CuL), and particulate (CuP). Cu wash-off time course was modeled for two different drop sizes using...... a stochastic model based on the cumulative detachment by random scattered raindrop impacts. In other set of experiments, the influence of raindrop size, fall height, and fungicide dose was analyzed statistically by means of a full factorial design. Most Cu was lost as particles sized from 0.3 to 1 lm...... area that exhaust non-rainfast fungicide (4.2 ± 3.0 small drops and 2.5 ± 0.5 large drops for the high performance level, low performance level needed 30 ± 10 large drops and 40 ± 88 small drops), and the mass washed-off by a single-drop impact (from 1.27 ± 0.2 lg Cu to 3 ± 1 ng Cu per impact...

  3. Retention of copper originating from different fungicides in contrasting soil types

    International Nuclear Information System (INIS)

    Komarek, Michael; Vanek, Ales; Chrastny, Vladislav; Szakova, Jirina; Kubova, Karolina; Drahota, Petr; Balik, Jiri

    2009-01-01

    This work described the retention of Cu from two different commonly used pesticides, the Bordeaux mixture (CuSO 4 + Ca(OH) 2 ) and Cu-oxychloride (3Cu(OH) 2 .CuCl 2 ), and from Cu(NO 3 ) 2 in contrasting soil types (Leptosol, Chernozem, Cambisol). Thermodynamic modeling showed that Cu speciation was similar in all fungicide solutions. However, the retention of Cu differed with the fungicide used (maximum retention from the Bordeaux mixture) which indicates that different retention processes occurred in the studied soils. The suggested mechanisms include: specific and non-specific adsorption (especially on soil organic matter), precipitation of newly formed phases, such as CuO, Cu(OH) 2 , Cu 2 (OH) 3 NO 3 , CuCO 3 /Cu 2 (OH) 2 CO 3 and in the case of the Bordeaux mixture, precipitation of various Cu-hydroxysulfates. These phases were identified by the speciation model. The retention of fungicide-derived Cu in the studied soil types followed well the Freundlich isotherm and was directly controlled by the chemical form of Cu. This fact should be taken into account for both environmental and practical applications.

  4. Fungicidal Drugs Induce a Common Oxidative-Damage Cellular Death Pathway

    Directory of Open Access Journals (Sweden)

    Peter Belenky

    2013-02-01

    Full Text Available Amphotericin, miconazole, and ciclopirox are antifungal agents from three different drug classes that can effectively kill planktonic yeast, yet their complete fungicidal mechanisms are not fully understood. Here, we employ a systems biology approach to identify a common oxidative-damage cellular death pathway triggered by these representative fungicides in Candida albicans and Saccharomyces cerevisiae. This mechanism utilizes a signaling cascade involving the GTPases Ras1 and Ras2 and protein kinase A, and it culminates in death through the production of toxic reactive oxygen species in a tricarboxylic-acid-cycle- and respiratory-chain-dependent manner. We also show that the metabolome of C. albicans is altered by antifungal drug treatment, exhibiting a shift from fermentation to respiration, a jump in the AMP/ATP ratio, and elevated production of sugars; this coincides with elevated mitochondrial activity. Lastly, we demonstrate that DNA damage plays a critical role in antifungal-induced cellular death and that blocking DNA-repair mechanisms potentiates fungicidal activity.

  5. [Effects of bio-organic fertilizer and fungicide application on continuous cropping obstacles of cut chrysanthemum].

    Science.gov (United States)

    Chen, Xi; Zhao, Shuang; Yao, Jian-jun; Ye, Yan-ping; Song, Ai-ping; Chen, Fa-di; Chen, Su-mei; Dong, Xue-na

    2015-04-01

    Abstract: Fusarium wilt is a soil borne disease caused by plant continuous cropping in monoculture Chrysanthemum morifolium 'Youxiang' monoculture not only declines plant quality and yield but also decreases soil enzymes and soil microbial diversity over successive cultivation. In this article, the effects of fungicide (Carbendazim MBC), antifungal enhanced bio-organic fertilizer (BOF), and their combined application on the quality and soil enzymes activities of Chrysanthemum morifolium 'Youxiang' in continuous cropping systems were investigated. The results showed that both bioorganic fertilizer (BOF) and fungicide (MBC) single application could effectively prevent the occurrence of Fusarium wilt disease of cut chrysanthemum. Bio-organic fertilizer application was more effective on root activity, soil enzymes activities and quality (shoot height, stem diameter, leaf SPAD value, ray floret number, shoot fresh mass) improvement of cut chrysanthemum, while fungicide single application was responsible for soil enzymatic activities suppression to some extent. The combined application treatment (MBC+BOF) showed the best effects on quality improvement and soil enzyme activities promotion.

  6. ENVIRONMENTAL RISK ASSESSMENT OF SOME COPPER BASED FUNGICIDES ACCORDING TO THE REQUIREMENTS OF GOOD LABORATORY PRACTICE

    Directory of Open Access Journals (Sweden)

    Marga GRĂDILĂ

    2015-10-01

    Full Text Available The paper presents data demonstrating the functionality of biological systems reconstituted with aquatic organisms developed under Good Laboratory Practice testing facility within Research - Development Institute for Plant Protection Bucharest for environmental risk assessment of four fungicides based on copper, according to Good Laboratory Practice requirements. For risk assessment, according to GLP were made the following steps: Good Laboratory Practice test facility was established, we have ensured adequate space for growth, acclimatization and testing for each test species, it was installed a complex water production instalation needed to perform tests, it was achieved control system for checking environmental conditions and have developed specific operating procedures that have been accredited according to Good Laboratory Practice.The results showed that biological systems model of the Good Laboratory Practice test facility in Research - Development Institute for Plant Protection meet the requirements of Organisation for Economic Co-operation and Development Guidelines regarding GLP, and after testing copper-based fungicides in terms of acute toxicity Cyprinus carpio and to Daphnia magna revealed that three of them (copper oxychloride, copper hydroxide and copper sulphate showed ecological efficiency, ie low toxicity. Metallic copper based fungicides showed a higher toxicity, resulting in fish toxicity symptoms: sleep, sudden immersion, faded, weakness, swimming in spiral, lack of balance, breathing slow and cumbersome, spasms and mortality.

  7. The Effect of Fungicides for Seed Treatment on Germination of Barley

    Directory of Open Access Journals (Sweden)

    Vesna Stevanović

    2009-01-01

    Full Text Available The application of chemicals, such as fungicides for seed treatment, is one of the most reliable and perhaps most efficient measures for integrated preservation of crops, and its practicing has become a legal obligation for all seed producers. This investigation was carried out in the laboratory for seed quality and phytopathology of the Small Grains Research Center in Kragujevac. The objective was to establish the effect of fungicides on germination energy and seed germinability (determined after treatments. Two varieties were tested due to a possibility of specific sensitivities of some varieties, so that the results acquired on one variety would not necessarily be valid for another one. Fungicides based on active ingredients from the triasol chemical group had different effects on the energy of germination of barley seeds. Applying Raxil S040-FS, the average germination of barley seeds was 79.3% for the variety Record, and 91.3% for the Grand variety. The variety Record achieved a lower value than the minimum for barley seed germination (88% stipulated by the Rules on Seed Quality of Agricultural Crops.Regardless of barley type, the product Raxil S040-FS showed a statistically significant effect on the number of atypical seedlings and increase in the number of non-germinated seeds, compared to the control.

  8. Late Blight of Potato (Phytophthora infestans I: Fungicides Application and Associated Challenges

    Directory of Open Access Journals (Sweden)

    Abdul Majeed

    2017-03-01

    Full Text Available Potato (Solanum tuberosum L. has been remained an important agricultural crop in resolving global food issues through decades. The crop has experienced enormous growth in terms of production throughout the world in recent decades because of improvement in agricultural mechanization, fertilizers application and irrigation practices. Nevertheless, a significant proportion of this valuable crop is still vulnerable to losses due to prevalence of different viral, bacterial, fungal and nematodes infestations. Late blight, caused by Phytophthora infestans (Mont. de Bary, is one of the most threatening pathogenic diseases which not only results in direct crop losses but also cause farmers to embrace huge monetary expenses for disease control and preventive measures. The disease is well known for notorious ‘Irish Famine’ which resulted in drop of Irish population by more than 20% as result of hunger and potato starvation. Globally, annual losses of crop and money spend on fungicides for late blight control exceeds one trillion US dollars. This paper reviews the significance of late blight of potato and controlling strategies adopted for minimizing yield losses incurred by this disease by the use of synthetic fungicides. Advantages and disadvantages of fungicides application are discussed.

  9. Influence of fungicides on occurence of Fusarium spp. and other stem base diseases on winter wheat

    Directory of Open Access Journals (Sweden)

    Václav Sklenář

    2008-01-01

    Full Text Available From 1999 to 2004 the occurence of fungi: Pseudocercosporella herpotrichoides (Fron. and Fusarium spp. was evaluated in small plot field trials on seven varieties of winter wheat. The efficacy of fungicide protection against stem base diseases and influence on yields was monitored in field conditions in Velká Bystřice near Olomouc.For diagnostic of casual fungi two methods were used: 1. Method of coloring mycelium in stems, 2. Method of cultivation of mycelim on agar.Results from detection of casual fungi are following: Pseudocercosporella herpotrichoides (Fron., Fusarium culmorum (W. G. Sm. Sacc. and Fusarium graminearum Schwabe.For high efficacy of protection against roots and stem base disease the following fungicide variants should be applied: Sportak Alpha 1.5 l . ha−1 (BBCH 30/Cerelux Plus 0.7 l . ha−1 (BBCH 51, Sportak HF 1 l . ha−1 (BBCH 30/Cerelux Plus 0.7 l . ha−1, Alert S 1.0 l . ha−1 (BBCH 30/Cerelux Plus 0.7 l . ha−1 (BBCH 51. The application of fungicides positively influenced yields. Yield increased at average by10–20 % after the aplication but the rise in yields was not in total correlation with the efficacy. These results can be possibly used in the system of integral control of winter wheat against stem base disease in wheat.

  10. Effect of Fungicide Applications on Grain Sorghum (Sorghum bicolor L. Growth and Yield

    Directory of Open Access Journals (Sweden)

    Dan D. Fromme

    2017-01-01

    Full Text Available Field studies were conducted in the upper Texas Gulf Coast and in central Louisiana during the 2013 through 2015 growing seasons to evaluate the effects of fungicides on grain sorghum growth and development when disease pressure was low or nonexistent. Azoxystrobin and flutriafol at 1.0 L/ha and pyraclostrobin at 0.78 L/ha were applied to the plants of two grain sorghum hybrids (DKS 54-00, DKS 53-67 at 25% bloom and compared with the nontreated check for leaf chlorophyll content, leaf temperature, and plant lodging during the growing season as well as grain mold, test weight, yield, and nitrogen and protein content of the harvested grain. The application of a fungicide had no effect on any of the variables tested with grain sorghum hybrid responses noted. DKS 53-67 produced higher yield, greater test weight, higher percent protein, and N than DKS 54-00. Results of this study indicate that the application of a fungicide when little or no disease is present does not promote overall plant health or increase yield.

  11. Soybean (Glycine max L. Response to Fungicides in the Absence of Disease Pressure

    Directory of Open Access Journals (Sweden)

    W. James Grichar

    2013-01-01

    Full Text Available Field studies were conducted during the 2010 and 2011 growing seasons along the Texas Upper Gulf Coast region to study the effects of fungicides on soybean disease development and to evaluate the response of four soybean cultivars to prothioconazole plus trifloxystrobin and pyraclostrobin. In neither year did any soybean diseases develop enough to be an issue. Only NKS 51-T8 responded to a fungicide treatment in 2010 while HBK 5025 responded in 2011. Prothioconazole plus trifloxystrobin increased NKS 51-T8 yield by 23% in 2010 while in 2011 the yield of HBK 5025 was increased 14% over the unsprayed check. No yield response was noted with pyraclostrobin on any soybean cultivar. Only prothioconazole + trifloxystrobin applied to either NKS 51-T8 or DP5335 in 2010 resulted in a net increase in dollars per hectare over the unsprayed check of the respective cultivar. In 2011, under extremely dry conditions, all fungicides with the exception of prothioconazole + trifloxystrobin applied to HBK 5025 resulted in a net decrease in returns over the unsprayed check.

  12. Assessment of Total Risk on Non-Target Organisms in Fungicide Application for Agricultural Sustainability

    Directory of Open Access Journals (Sweden)

    Ali Musa Bozdogan

    2014-02-01

    Full Text Available In Turkey, in 2010, the amount of pesticide (active ingredient; a.i. used in agriculture was about 23,000 metric tons, of which approximately 32% was fungicides. In 2012, 14 a.i. were used for fungus control in wheat cultivation areas in Adana province, Turkey. These a.i. were: azoxystrobin, carbendazim, difenoconazole, epoxiconazole, fluquinconazole, prochloraz, propiconazole, prothioconazole, pyraclostrobin, spiroxamine, tebuconazole, thiophanate-methyl, triadimenol, and trifloxystrobin. In this study, the potential risk of a.i. on non-target organisms in fungicide application of wheat cultivation was assessed by The Pesticide Occupational and Environmental Risk (POCER indicators. In this study, the highest human health risk was for fluquinconazole (Exceedence Factor (EF 1.798 for human health, whereas the fungicide with the highest environmental risk was propiconazole (EF 2.000 for the environment. For non-target organisms, the highest potential risk was determined for propiconazole when applied at 0.1250 kg a.i. ha-1 (EF 2.897. The lowest total risk was for azoxystrobin when applied at  0.0650 kg a.i. ha-1 (EF 0.625.

  13. Effect of foliar fertilizer and fungicidal protection against leaf spot diseases on winter wheat

    Directory of Open Access Journals (Sweden)

    Agnieszka Mączyńska

    2012-12-01

    Full Text Available Field experiments were carried out in the seasons 2000/2001 and 2001/2002 in Plant Protection Institute, Sooenicowice Branch to assess the influence of foliar fertilizers such as Ekolist PK 1, Ekolist Mg, Mikrosol Z and Urea on healthiness of winter wheat. Foliar fertilizers were mixed with fungicides. The fungicides were applied at full or half recommended doses. The effect of the disease on wheat leaves was evaluated three times in each vegetation season. Remaining green leaf area (GLA of leaves was also determined. GLA of the leaves F-1 was not significantly different for each combination with different fertilization and different levels of chemical treatment. The application of foliar fertilizer only had no effect on green leaf area (GLA. The results indicate that foliar fertilization of all experimental plots improved leaf condition and therefore halted the development of wheat leaf diseases. The increases of 1000 grain mass and yield was high for each plot where a fertilizer and a full or half dose of a fungicide was applied. Foliar fertilizing with no chemical control had no proven effect on studied parameters.

  14. Retention of copper originating from different fungicides in contrasting soil types.

    Science.gov (United States)

    Komárek, Michael; Vanek, Ales; Chrastný, Vladislav; Száková, Jirina; Kubová, Karolina; Drahota, Petr; Balík, Jirí

    2009-07-30

    This work described the retention of Cu from two different commonly used pesticides, the Bordeaux mixture (CuSO(4)+Ca(OH)(2)) and Cu-oxychloride (3Cu(OH)(2).CuCl(2)), and from Cu(NO(3))(2) in contrasting soil types (Leptosol, Chernozem, Cambisol). Thermodynamic modeling showed that Cu speciation was similar in all fungicide solutions. However, the retention of Cu differed with the fungicide used (maximum retention from the Bordeaux mixture) which indicates that different retention processes occurred in the studied soils. The suggested mechanisms include: specific and non-specific adsorption (especially on soil organic matter), precipitation of newly formed phases, such as CuO, Cu(OH)(2), Cu(2)(OH)(3)NO(3), CuCO(3)/Cu(2)(OH)(2)CO(3) and in the case of the Bordeaux mixture, precipitation of various Cu-hydroxysulfates. These phases were identified by the speciation model. The retention of fungicide-derived Cu in the studied soil types followed well the Freundlich isotherm and was directly controlled by the chemical form of Cu. This fact should be taken into account for both environmental and practical applications.

  15. Retention of copper originating from different fungicides in contrasting soil types

    Energy Technology Data Exchange (ETDEWEB)

    Komarek, Michael, E-mail: komarek@af.czu.cz [Department of Agro-Environmental Chemistry and Plant Nutrition, Czech University of Life Sciences Prague, Kamycka 129, 165 21, Prague 6 (Czech Republic); Vanek, Ales [Department of Soil Science and Soil Protection, Czech University of Life Sciences Prague, Kamycka 129, 165 21, Prague 6 (Czech Republic); Chrastny, Vladislav [Department of Applied Chemistry, University of South Bohemia, Studentska 13, 370 05, Ceske Budejovice (Czech Republic); Szakova, Jirina; Kubova, Karolina [Department of Agro-Environmental Chemistry and Plant Nutrition, Czech University of Life Sciences Prague, Kamycka 129, 165 21, Prague 6 (Czech Republic); Drahota, Petr [Institute of Geochemistry, Mineralogy and Mineral Resources, Charles University Prague, Albertov 6, 128 43, Prague 2 (Czech Republic); Balik, Jiri [Department of Agro-Environmental Chemistry and Plant Nutrition, Czech University of Life Sciences Prague, Kamycka 129, 165 21, Prague 6 (Czech Republic)

    2009-07-30

    This work described the retention of Cu from two different commonly used pesticides, the Bordeaux mixture (CuSO{sub 4} + Ca(OH){sub 2}) and Cu-oxychloride (3Cu(OH){sub 2}.CuCl{sub 2}), and from Cu(NO{sub 3}){sub 2} in contrasting soil types (Leptosol, Chernozem, Cambisol). Thermodynamic modeling showed that Cu speciation was similar in all fungicide solutions. However, the retention of Cu differed with the fungicide used (maximum retention from the Bordeaux mixture) which indicates that different retention processes occurred in the studied soils. The suggested mechanisms include: specific and non-specific adsorption (especially on soil organic matter), precipitation of newly formed phases, such as CuO, Cu(OH){sub 2}, Cu{sub 2}(OH){sub 3}NO{sub 3}, CuCO{sub 3}/Cu{sub 2}(OH){sub 2}CO{sub 3} and in the case of the Bordeaux mixture, precipitation of various Cu-hydroxysulfates. These phases were identified by the speciation model. The retention of fungicide-derived Cu in the studied soil types followed well the Freundlich isotherm and was directly controlled by the chemical form of Cu. This fact should be taken into account for both environmental and practical applications.

  16. Degradation and sorption of the fungicide tebuconazole in soils from golf greens.

    Science.gov (United States)

    Badawi, Nora; Rosenbom, Annette E; Jensen, Anne M D; Sørensen, Sebastian R

    2016-12-01

    The fungicide tebuconazole (TBZ) is used to repress fungal growth in golf greens and ensure their playability. This study determined the degradation and sorption of TBZ applied as an analytical grade compound, a commercial fungicide formulation or in combination with a surfactant product in thatch and soils below two types of greens (USGA and push-up greens) in 12-cm vertical profiles covered by three different types of turf grass. Only minor TBZ degradation was observed and it was most pronounced in treatments with the commercial fungicide product or in combination with the surfactant compared to the analytical grade compound alone. A tendency for higher TBZ sorption when applied as the formulated product and lowest sorption when applied as a formulated product in combination with the surfactant was observed, with this effect being most distinct on USGA greens. No correlation between occurrence of degradation and soil depth, green type or grass type was observed. Sorption seemed to be the main process governing the leaching risk of TBZ from the greens and a positive correlation to the organic matter content was shown. In light of these findings, organic matter content should be taken into consideration during the construction of golf courses, especially when following USGA guidelines. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Biosynthesis and metabolic pathways of pivalic acid

    Czech Academy of Sciences Publication Activity Database

    Řezanka, Tomáš; Kolouchová, I.; Čejková, A.; Sigler, Karel

    2012-01-01

    Roč. 95, č. 6 (2012), s. 1371-1376 ISSN 0175-7598 R&D Projects: GA ČR(CZ) GAP503/11/0215 Institutional support: RVO:61388971 Keywords : Pivalic acid * Isooctane * Biosynthesis Subject RIV: EE - Microbiology, Virology Impact factor: 3.689, year: 2012

  18. Combinatorial biosynthesis of medicinal plant secondary metabolites

    NARCIS (Netherlands)

    Julsing, Mattijs K.; Koulman, Albert; Woerdenbag, Herman J.; Quax, Wim J.; Kayser, Oliver

    2006-01-01

    Combinatorial biosynthesis is a new tool in the generation of novel natural products and for the production of rare and expensive natural products. The basic concept is combining metabolic pathways in different organisms on a genetic level. As a consequence heterologous organisms provide precursors

  19. Biosynthesis of silver nanoparticles synthesized by Aspergillus

    Indian Academy of Sciences (India)

    In the present study, biosynthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic activities were investigated. Silver nanoparticles were extracellularly synthesized using Aspergillus flavus and the formation of nanoparticles was observed after 72 h of incubation. The results recorded from colour ...

  20. Bile acid biosynthesis and its regulation

    Directory of Open Access Journals (Sweden)

    Areta Hebanowska

    2010-10-01

    Full Text Available Bile acid biosynthesis is the main pathway of cholesterol catabolism. Bile acids are more soluble than cholesterol so are easier to excrete. As amphipathic molecules they participate in lipid digestion and absorption in the intestine and they help to excrete free cholesterol with bile. They are also ligands for nuclear receptors regulating the expression of genes involved in cholesterol metabolism. Interconversion of cholesterol into bile acids is an important point of its homeostasis. Seventeen enzymes are engaged in this process and many of them are cytochromes P450. Bile acid synthesis initiation may proceed with the “classical” pathway (starting with cholesterol hydroxylation at the C7α position or the “alternative” pathway (starting with cholesterol hydroxylation at the C27 position. Two additional pathways are possible, though their quantitative significance is small (initiated with cholesterol hydroxylations of C24 and C25 positions. Oxysterols produced are not only intermediates of bile acid biosynthesis but also important regulators of metabolism. Bile acid biosynthesis takes place in the liver, but some enzymes are also present in other organs, where they participate in regulation of cholesterol metabolism. Those enzymes are potential targets for new drugs against cholesterol metabolism disturbances. This article is a brief description of the bile acid biosynthesis pathway and participating enzymes.

  1. Biosynthesis of polyhydroxyalkanotes in wildtype yeasts | Desuoky ...

    African Journals Online (AJOL)

    Biosynthesis of the biodegradable polymers polyhydroxyalkanotes (PHAs) are studied extensively in wild type and genetically modified prokaryotic cells, however the content and structure of PHA in wild type yeasts are not well documented. The purpose of this study was to screen forty yeast isolates collected from different ...

  2. Unedoside derivatives in Nuxia and their biosynthesis

    DEFF Research Database (Denmark)

    Jensen, Søren Rosendal; Ravnkilde, Lene; Schripsema, Jan

    1998-01-01

    isolated, while from N. oppositifolia 2 "-acetyl-3 "-benzoyl-nuxioside was obtained. Both plants contained verbascoside. The biosynthesis of unedoside in N. floribunda was investigated and deoxyloganic acid was found to be a precursor, similar to wh;lt was found for the eight-carbon iridoids in Thunbergia...

  3. Biosynthesis of furanochromones in Pimpinella monoica

    Indian Academy of Sciences (India)

    polyketide origin of their aromatic and pyrone rings while the furan ring originates via an acetate-mevalonate pathway. The plant also utilises glycine and leucine as substrate via acetate. Biotransformation of 3-H-visnagin to (6) but not to (2) was also observed. Keywords. Biosynthesis; furochromones; polyketide origin; ...

  4. Biosynthesis of silver nanoparticles synthesized by Aspergillus ...

    Indian Academy of Sciences (India)

    In the present study, biosynthesis of silver nanoparticles and its antioxidant, antimicrobial and cytotoxic activities were investigated. Silver nanoparticles were extracellularly synthesized using Aspergillus flavus and the formation of nanoparticles was observed after 72 h of incubation. The results recorded from colour ...

  5. Efeito de fungicidas na germinação in vitro de conídios de Claviceps africana Fungicides effect on conidia germination of Claviceps africana in vitro

    Directory of Open Access Journals (Sweden)

    Sônia Regina Nogueira

    2002-10-01

    Full Text Available A cultura do sorgo não enfrentava problemas sérios de doenças nas condições de cultivo no Brasil, até o ano de 1995, quando se registrou a ocorrência da doença-açucarada, causada por Claviceps africana, que afeta as panículas e reduz a quantidade e a qualidade dos grãos; os conídios constituem a principal fonte de inóculo fúngico. Este trabalho teve como objetivo estudar o efeito dos fungicidas tebuconazole, propiconazole, triadimenol, triadimefon, flutriafol e mancozeb na inibição in vitro da germinação dos conídios. Os fungicidas mancozeb, triadimenol e propiconazole foram os mais eficientes na inibição da germinação dos conídios.The sorghum crop did not face serious problems with diseases in Brazil, until occurrence of sugary disease (sorghum ergot, caused by Claviceps africana, was recorded in 1995 in Brazilian sorghum fields. The pathogen infects panicles reducing the quantity and quality of the produced grains. Conidia are the main fungus inoculum. This work aimed to study the potential of fungicides tebuconazole, propiconazole, triadimenol, triadimefon, flutriafol and mancozeb in inhibiting conidia germination in vitro. The fungicides mancozeb, triadimenol and propiconazole were the most effective to inhibit the in vitro germination.

  6. Evidence for synergistic control of glutamate biosynthesis by glutamate dehydrogenases and glutamate in Bacillus subtilis.

    Science.gov (United States)

    Stannek, Lorena; Thiele, Martin J; Ischebeck, Till; Gunka, Katrin; Hammer, Elke; Völker, Uwe; Commichau, Fabian M

    2015-09-01

    In the Gram-positive bacterium, Bacillus subtilis glutamate is synthesized by the glutamine synthetase and the glutamate synthase (GOGAT). During growth with carbon sources that exert carbon catabolite repression, the rocG glutamate dehydrogenase (GDH) gene is repressed and the transcription factor GltC activates the expression of the GOGAT encoding gltAB genes. In the presence of amino acids of the glutamate family, the GDH RocG is synthesized and the enzyme prevents GltC from binding to DNA. The dual control of glutamate biosynthesis allows the efficient utilization of the available nutrients. Here we provide genetic and biochemical evidence that, like RocG, also the paralogous GDH GudB can inhibit the transcription factor GltC, thereby controlling glutamate biosynthesis. Contradictory previous observations show that high level of GDH activity does not result in permanent inhibition of GltC. By controlling the intracellular levels of glutamate through feeding with exogenous arginine, we observed that the GDH-dependent control of GltC and thus expression of the gltAB genes inversely correlates with the glutamate pool. These results suggest that the B. subtilis GDHs RocG and GudB in fact act as glutamate sensors. In conclusion, the GDH-mediated control of glutamate biosynthesis seems to depend on the intracellular glutamate concentration. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Competition between ethanol clearance and retinoic acid biosynthesis in the induction of fetal alcohol syndrome.

    Science.gov (United States)

    Shabtai, Yehuda; Fainsod, Abraham

    2018-04-01

    Several models have been proposed to explain the neurodevelopmental syndrome induced by exposure of human embryos to alcohol, which is known as fetal alcohol spectrum disorder (FASD). One of the proposed models suggests a competition for the enzymes required for the biosynthesis of retinoic acid. The outcome of such competition is development under conditions of reduced retinoic acid signaling. Retinoic acid is one of the biologically active metabolites of vitamin A (retinol), and regulates numerous embryonic and differentiation processes. The developmental malformations characteristic of FASD resemble those observed in vitamin A deficiency syndrome as well as from inhibition of retinoic acid biosynthesis or signaling in experimental models. There is extensive biochemical and enzymatic overlap between ethanol clearance and retinoic acid biosynthesis. Several lines of evidence suggest that in the embryo, the competition takes place between acetaldehyde and retinaldehyde for the aldehyde dehydrogenase activity available. In adults, this competition also extends to the alcohol dehydrogenase activity. Ethanol-induced developmental defects can be ameliorated by increasing the levels of retinol, retinaldehyde, or retinaldehyde dehydrogenase. Acetaldehyde inhibits the production of retinoic acid by retinaldehyde dehydrogenase, further supporting the competition model. All of the evidence supports the reduction of retinoic acid signaling as the etiological trigger in the induction of FASD.

  8. Griseorhodins D-F, neuroactive intermediates and end products of post-PKS tailoring modification in Griseorhodin biosynthesis.

    Science.gov (United States)

    Lin, Zhenjian; Zachariah, Malcolm M; Marett, Lenny; Hughen, Ronald W; Teichert, Russell W; Concepcion, Gisela P; Haygood, Margo G; Olivera, Baldomero M; Light, Alan R; Schmidt, Eric W

    2014-05-23

    The griseorhodins belong to a family of extensively modified aromatic polyketides that exhibit activities such as inhibition of HIV reverse transcriptase and human telomerase. The vast structural diversity of this group of polyketides is largely introduced by enzymatic oxidations, which can significantly influence the bioactivity profile. Four new compounds, griseorhodins D-F, were isolated from a griseorhodin producer, Streptomyces sp. CN48+, based upon their enhancement of calcium uptake in a mouse dorsal root ganglion primary cell culture assay. Two of these compounds, griseorhodins D1 and D2, were shown to be identical to the major, previously uncharacterized products of a grhM mutant in an earlier griseorhodin biosynthesis study. Their structures enabled the establishment of a more complete hypothesis for the biosynthesis of griseorhodins and related compounds. The other two compounds, griseorhodins E and F, represent new products of post-polyketide synthase tailoring in griseorhodin biosynthesis and showed significant binding activity in a human dopamine active transporter assay.

  9. Dephosphorylated NPr of the nitrogen PTS regulates lipid A biosynthesis by direct interaction with LpxD.

    Science.gov (United States)

    Kim, Hyun-Jin; Lee, Chang-Ro; Kim, Miri; Peterkofsky, Alan; Seok, Yeong-Jae

    2011-06-10

    Bacterial phosphoenolpyruvate-dependent phosphotransferase systems (PTS) play multiple roles in addition to sugar transport. Recent studies revealed that enzyme IIA(Ntr) of the nitrogen PTS regulates the intracellular concentration of K(+) by direct interaction with TrkA and KdpD. In this study, we show that dephosphorylated NPr of the nitrogen PTS interacts with Escherichia coli LpxD which catalyzes biosynthesis of lipid A of the lipopolysaccharide (LPS) layer. Mutations in lipid A biosynthetic genes such as lpxD are known to confer hypersensitivity to hydrophobic antibiotics such as rifampin; a ptsO (encoding NPr) deletion mutant showed increased resistance to rifampin and increased LPS biosynthesis. Taken together, our data suggest that unphosphorylated NPr decreases lipid A biosynthesis by inhibiting LpxD activity. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. Evidence of low dose effects of the antidepressant fluoxetine and the fungicide prochloraz on the behavior of the keystone freshwater invertebrate Gammarus pulex.

    Science.gov (United States)

    De Castro-Català, N; Muñoz, I; Riera, J L; Ford, A T

    2017-12-01

    In recent years, behavior-related endpoints have been proposed as rapid and reliable ecotoxicological tools for risk assessment. In particular, the use of detritivores to test the toxicity of pollutants through feeding is currently becoming a well-known method. Experiments combining feeding with other behavioral endpoints can provide relevant information about direct and indirect toxicological effects of chemicals. We carried out a feeding experiment with the shredder Gammarus pulex in order to detect indirect (through leaf conditioning) and direct effects (through water exposure) of two pollutants at environmentally relevant concentrations: the fungicide prochloraz (6 μg/L) and the antidepressant fluoxetine (100 ng/L). Prochloraz inhibited fungal growth on leaves, but it did not affect either the microbial breakdown rates or the C:N ratio of the leaves. Individuals of G. pulex that were fed with treated leaves presented lower consumption rates, not only those fed with prochloraz-treated leaves, but also those fed with fluoxetine-treated leaves, and those fed with the mixture-treated leaves. Mixed-effects models revealed that the swimming velocity of the amphipods after the experiment was modulated by the exposure to fluoxetine, and also by the exposure to prochloraz. We demonstrate that both the antidepressant and the fungicide may cause significant sublethal effects at low concentrations. The combination of behavioral endpoints together with the application of mixed models provided a useful tool for early detection of the effects of toxicity mixtures in freshwater ecosystems. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. PROCHLORAZ INHIBITS TESTOSTERONE PRODUCTION AT DOSAGE LEVELS BELOW THOSE THAT AFFECT ANDROGEN-DEPENDENT ORGAN WEIGHTS OR THE ONSET OF MALE RAT PUBERTY

    Science.gov (United States)

    Prochloraz (PCZ) is an imidazole fungicide that has several endocrine modes of action. In vitro, PCZ inhibits steroidogenesis and acts as an androgen receptor (AR) antagonist. We hypothesized that pubertal exposure to prochloraz would delay preputial separation and growth of an...

  12. Metabolic modeling of polyhydroxybutyrate biosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Leaf, T.A.; Srienc, F. [Univ. of Minnesota, St. Paul, MN (United States)

    1998-03-05

    A mathematical model describing intracellular polyhydroxybutyrate (PHB) synthesis in Alcaligenes eutrophus has been constructed. The model allows investigation of issues such as the existence of rate-limiting enzymatic steps, possible regulatory mechanisms in PHB synthesis, and the effects different types of rate expressions have on model behavior. Simulations with the model indicate that activities of all PHB pathway enzymes influence overall PHB flux and that no single enzymatic step can easily be identified as rate limiting. Simulations also support regulatory roles for both thiolase and reductase, mediated through AcCoA/CoASH and NADPH/NADP+ ratios, respectively. To make the model more realistic, complex rate expressions for enzyme-catalyzed reactions were used which reflect both the reversibility of the reactions and the reaction mechanisms. Use of the complex kinetic expressions dramatically changed the behavior of the system compared to a simple model containing only Michaelis-Menten kinetic expressions; the more complicated model displayed different responses to changes in enzyme activities as well as inhibition of flux by the reaction products CoASH and NADP+. These effects can be attributed to reversible rate expressions, which allow prediction of reaction rates under conditions both near and far from equilibrium.

  13. Biosynthesis of the Peptide Antibiotic Feglymycin by a Linear Nonribosomal Peptide Synthetase Mechanism.

    Science.gov (United States)

    Gonsior, Melanie; Mühlenweg, Agnes; Tietzmann, Marcel; Rausch, Saskia; Poch, Annette; Süssmuth, Roderich D

    2015-12-01

    Feglymycin, a peptide antibiotic produced by Streptomyces sp. DSM 11171, consists mostly of nonproteinogenic phenylglycine-type amino acids. It possesses antibacterial activity against methicillin-resistant Staphylococcus aureus strains and antiviral activity against HIV. Inhibition of the early steps of bacterial peptidoglycan synthesis indicated a mode of action different from those of other peptide antibiotics. Here we describe the identification and assignment of the feglymycin (feg) biosynthesis gene cluster, which codes for a 13-module nonribosomal peptide synthetase (NRPS) system. Inactivation of an NRPS gene and supplementation of a hydroxymandelate oxidase mutant with the amino acid l-Hpg proved the identity of the feg cluster. Feeding of Hpg-related unnatural amino acids was not successful. This characterization of the feg cluster is an important step to understanding the biosynthesis of this potent antibacterial peptide. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Action of radiation on biosynthesis of hemoglobin and some of its electrophoretic fractions

    International Nuclear Information System (INIS)

    Starodub, N.F.; Kriklivyj, I.A.; Shur'yan, I.M.

    1976-01-01

    Biosynthesis of hemoglobin and some of its electrophoretic fractions in red cells of peripheral blood and spleen of irradiated (650 R) rats has been studied. Hemoglobin synthesis is found to be most drastically inhibited in the first and second fractions on the first and eighth days after irradiation and in the fifth and sixth fractions on the eighth day (less expressed). The synthesis is restored on the twelfth day, the process under study proceeding more slowly in the above-mentioned fractions than in others. In the course of radiation sickness, the biosynthesis of certain hemoglobin fractions varies differently in the hemoglobin-synthesizing cells of peripheral blood than in the cells of spleenic erythroid series

  15. Waterborne toxicity and diet-related effects of fungicides in the key leaf shredder Gammarus fossarum (Crustacea: Amphipoda).

    Science.gov (United States)

    Zubrod, J P; Englert, D; Wolfram, J; Wallace, D; Schnetzer, N; Baudy, P; Konschak, M; Schulz, R; Bundschuh, M

    2015-12-01

    Animals involved in leaf litter breakdown (i.e., shredders) play a central role in detritus-based stream food webs, while their fitness and functioning can be impaired by anthropogenic stressors. Particularly fungicides can affect shredders via both waterborne exposure and their diet, namely due to co-ingestion of adsorbed fungicides and shifts in the leaf-associated fungal community, on which shredders' nutrition heavily relies. To understand the relevance of these effect pathways, we used a full 2×2-factorial test design: the leaf material serving as food was microbially colonized for 12 days either in a fungicide-free control or exposed to a mixture of five current-use fungicides (sum concentration of 62.5μg/L). Similarly, the amphipod shredder Gammarus fossarum was subjected to the same treatments but for 24 days. Waterborne exposure reduced leaf consumption by ∼20%, which did not fully explain the reduction in feces production (∼30%), indicating an enhanced utilization of food to compensate for detoxification mechanisms. This may also explain the reduced feces production (∼10%) of gammarids feeding on fungicide-exposed leaves. The reduction may, however, also be caused by a decreased nutritious quality of the leaves indicated by a reduced species richness (∼40%) of leaf-associated fungi. However, compensation for these effects by Gammarus was seemingly incomplete, since both waterborne exposure and the consumption of the fungicide-affected diet drastically reduced gammarid growth (∼110% and ∼40%, respectively). Our results thus indicate that fungicide mixtures have the potential for detrimental implications in aquatic ecosystem functioning by affecting shredders via both effect pathways. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Comparative hygienic assessment of active ingredients content in the air environment after treatment of cereal spiked crops by combined fungicides.

    Science.gov (United States)

    Kondratiuk, Mykola; Blagaia, Anna; Pelo, Ihor

    2018-01-01

    Introduction: The quality of the air environment significantly affects the health of the population. Chemical plant protection products in the spring and summer time may be the main pollutants of the air environment in rural areas. Chemical plant protection products are dangerous substances of anthropogenic origin. If applying pesticides in high concentrations, the risk of poisoning by active ingredients of pesticide preparations in workers directly contacting with it increases. The aim: Comparative hygienic assessment of active ingredients content in the air environment after treatment of cereal spiked crops by combined fungicides was the aim of the work. Materials and methods: Active ingredients of the studied combined fungicides, samples of air, and swabs from workers' skin and stripes from overalls were materials of the research. Methods of full-scale in-field hygienic experiment, gas-liquid chromatography, high-performance liquid chromatography, as well as statistical and bibliographic methods were used in the research. Results and conclusions: Active ingredients of the studied combined fungicides were not detected in the working zone air and atmospheric air at the levels exceeding the limits of its detection by appropriate chromatography methods. Findings confirmed the air environment safety for agricultural workers and rural population if studied combined fungicides are applied following the hygienically approved suggested application rates and in accordance of good agricultural practice rules. However the possible complex risk for workers after certain studied fungicides application may be higher than acceptable due to the elevated values for dermal effects. The complex risk was higher than acceptable in еру case of aerial spraying of both studied fungicides, meanwhile only one combination of active ingredients revealed possible risk for workers applying fungicides by rod method of cereal spiked crops treatment.

  17. Trypanosoma cruzi response to sterol biosynthesis inhibitors: morphophysiological alterations leading to cell death.

    Directory of Open Access Journals (Sweden)

    Rafael Luis Kessler

    Full Text Available The protozoan parasite Trypanosoma cruzi displays similarities to fungi in terms of its sterol lipid biosynthesis, as ergosterol and other 24-alkylated sterols are its principal endogenous sterols. The sterol pathway is thus a potential drug target for the treatment of Chagas disease. We describe here a comparative study of the growth inhibition, ultrastructural and physiological changes leading to the death of T. cruzi cells following treatment with the sterol biosynthesis inhibitors (SBIs ketoconazole and lovastatin. We first calculated the drug concentration inhibiting epimastigote growth by 50% (EC(50/72 h or killing all cells within 24 hours (EC(100/24 h. Incubation with inhibitors at the EC(50/72 h resulted in interesting morphological changes: intense proliferation of the inner mitochondrial membrane, which was corroborated by flow cytometry and confocal microscopy of the parasites stained with rhodamine 123, and strong swelling of the reservosomes, which was confirmed by acridine orange staining. These changes to the mitochondria and reservosomes may reflect the involvement of these organelles in ergosterol biosynthesis or the progressive autophagic process culminating in cell lysis after 6 to 7 days of treatment with SBIs at the EC(50/72 h. By contrast, treatment with SBIs at the EC(100/24 h resulted in rapid cell death with a necrotic phenotype: time-dependent cytosolic calcium overload, mitochondrial depolarization and reservosome membrane permeabilization (RMP, culminating in cell lysis after a few hours of drug exposure. We provide the first demonstration that RMP constitutes the "point of no return" in the cell death cascade, and propose a model for the necrotic cell death of T. cruzi. Thus, SBIs trigger cell death by different mechanisms, depending on the dose used, in T. cruzi. These findings shed new light on ergosterol biosynthesis and the mechanisms of programmed cell death in this ancient protozoan parasite.

  18. Different biosynthesis patterns among flavonoid 3-glycosides with distinct effects on accumulation of other flavonoid metabolites in pears (Pyrus bretschneideri Rehd..

    Directory of Open Access Journals (Sweden)

    Rui Zhai

    Full Text Available Flavonoid biosynthesis profile was clarified by fruit bagging and re-exposure treatments in the green Chinese pear 'Zaosu' (Pyrus bretschneideri Rehd. and its red mutant 'Red Zaosu'. Two distinct biosynthesis patterns of flavonoid 3-glycosides were found in 'Zaosu' pear. By comparison with 'Red Zaosu', the biosynthesis of flavonoid 3-galactosides and flavonoid 3-arabinosides were inhibited by bagging and these compounds only re-accumulated to a small degree in the fruit peel of 'Zaosu' after the bags were removed. In contrast, the biosynthesis of flavonoid 3-gluctosides and flavonoid 3-rutinosides was reduced by bagging and then increased when the fruits were re-exposed to sunlight. A combination of correlation, multicollinearity test and partial-correlation analyses among major flavonoid metabolites indicated that biosynthesis of each phenolic compound was independent in 'Zaosu' pear, except for the positive correlation between flavonoid 3-rutincosides and flavanols. In contrast with the green pear cultivar, almost all phenolic compounds in the red mutant had similar biosynthesis patterns except for arbutin. However, only the biosynthesis of flavonoid 3-galactosides was relatively independent and strongly affected the synthesis of the other phenolic compounds. Therefore, we propose a hypothesis that the strong accumulation of flavonoid 3-galactosides stimulated the biosynthesis of other flavonoid compounds in the red mutant and, therefore, caused systemic variation of flavonoid biosynthesis profiles between 'Zaosu' and its red mutant. This hypothesis had been further demonstrated by the enzyme activity of UFGT, and transcript levels of flavonoid biosynthetic genes and been well tested by a stepwise linear regression forecasting model. The gene that encodes flavonoid 3-galacosyltransferase was also identified and isolated from the pear genome.

  19. Synthesis and biological evaluation of novel fluorine-containing stilbene derivatives as fungicidal agents against phytopathogenic fungi.

    Science.gov (United States)

    Jian, Weilin; He, Daohang; Xi, Pinggen; Li, Xinwei

    2015-11-18

    The rising development of resistance to conventional fungicides is driving the search for new alternative candidates to control plant diseases. In this study, a series of new fluorine-containing stilbene derivatives was synthesized on the basis of our previous quantitative structure-activity relationship analysis results. Bioassays in vivo revealed that the title compounds exhibited potent fungicidal activities against phytopathogenic fungi (Colletotrichum lagenarium and Pseudoperonospora cubensis) from cucumber plants. In comparison to the previous results, the introduction of a fluorine moiety showed improved activities of some compounds against those fungi. Notably, compound 9 exhibited a control efficacy against C. lagenarium (83.4 ± 1.3%) comparable to that of commercial fungicide (82.7 ± 1.7%). For further understanding the possible mode of action of the stilbene against C. lagenarium, the effects on hyphal morphology, electrolyte leakage, and respiration of mycelial cell suspension were studied. Microscopic observation showed considerably deformed mycelial morphology. The conductivity of mycelial suspension increased in the presence of compound 9, whereas no significantly inhibitory effect on respiration was observed. Taken together, the fungicidal mechanism of this stilbene is associated with its membrane disruption effect, resulting in increased membrane permeability. These results provide important clues for mechanistic study and derivatization of stilbenes as alternative sources of fungicidal agents for plant disease control.

  20. Occurrence of fungicide resistance in populations of Botryotinia fuckeliana (Botrytis cinerea) on table grape and strawberry in southern Italy.

    Science.gov (United States)

    De Miccolis Angelini, Rita Milvia; Rotolo, Caterina; Masiello, Mario; Gerin, Donato; Pollastro, Stefania; Faretra, Francesco

    2014-12-01

    Botryotinia fuckeliana (Botrytis cinerea) is a pathogen with a high risk of development of resistance to fungicides. Fungicide resistance was monitored during 2008-2011 in B. fuckeliana populations from both table-grape vineyards and greenhouse-grown strawberries in southern Italy. Isolates showing different levels of resistance to anilinopyrimidines (APs) were detected at high frequency (up to 98%) in fields treated intensively with APs (4-7 sprays season(-1) ). A slight decrease in sensitivity to fludioxonil, always combined with AP resistance, was generally found at lower frequencies. The repeated use of fenhexamid on grapevine (3-8 sprays season(-1) ) led to a strong selection of highly resistant isolates (up to 100%). Boscalid-resistant mutants were detected at very variable frequencies (0-73%). Occurrence of resistance to quinone outside inhibitors (QoIs) was also ascertained. Multiple fungicide resistance to 2-6 different modes of action were frequently recovered. Single nucleotide polymorphisms (SNPs) in the target genes Erg27, SdhB and cytb were associated with resistance to fenehexamid, boscalid and QoIs respectively. Resistance to the fungicides commonly used against grey mould on table grape and strawberry is quite common in southern Italy. This is an outcome of the incorrect use of fungicides, often because of the maximum number of detectable residues of plant protection products imposed by big international retailers, and underlines the crucial role of antiresistance strategies in integrated pest management. © 2013 Society of Chemical Industry.